| The sun and the
Photoprotection./ El sol y la Fotoproteccion. Data-Medicos
Dermagic/Express No. 66
21 Julio 1.999. 21 July 1.999.
~ El sol y la fotoprotección ~
~ The sun and the photoprotection ~
EDITORIAL ESPANOL
=================
Hola amigos Dermagicos. Nuestro Astro rey el sol es motor de nuestra vida y planeta, sin el no existiria nada sobre nuestra bella tierra, pero tambien debemos cuidarnos de sus efectos dañinos cuando nos exponemos excesivamente a la luz solar. El Dr Rolando Hernandez (Venezuela) me pidio una revisión sobre fotoproteccion y protectores solares. Encontre 67 interesantes referencias sobre el tema SOL Y FOTOPROTECCION, espero las disfruten.
Saludos a todos !!!
Dr. Jose Lapenta R.,,,
===========================MAIL -CORREO =========================
From: "Rolando Hernández" <[email protected]>
X-Mailer: Mozilla 4.03 [es] (Win95; I)
To: [email protected]
Subject: PERSONAL.Fotoprotección-Dermatología Tropica.
Amigo JJ Lapenta: permitame saludarle y felicitarle una vez más por su excelente trabajo de busqueda bibliografica en favor de la Dermatología Venezolana.
Amigo, estoy muy interesado y necesito con cierta urgencia información sobre:
a) Fotoprotección (fotoprotectores, nuevos fotoprotectores, fotoprotección oral (betacarotenos), vestimenta (tipo de trama en los tejidos, color, etc) y cualquier otra información relacionada con la "Prevención del Fotoenvejecimiento"
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EDITORIAL ENGLISH
=================
Hello friends Dermagicos. Our Star king the sun is motor of our life and planet, without him
anything would not exist on our beautiful earth, but we should also take care of their harmful effects
when we expose ourselves excessively to the solar light. The Dr Rolando Hernandez (Venezuela) requested a revision about photoprotection and sunscreens. I found 67 interesting references
on the topic THE SUN AND PHOTOPROTECTION. I wait enjoy it.
Greetings to ALL, !!
Dr. Jose Lapenta R.,,,
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REFERENCIAS BIBLIOGRAFICAS / BIBLIOGRAPHICAL REFERENCES
===================================================================
===================================================================
1.) Sun Smart Day: a pilot program for photoprotection education.
2.) The influence of sunscreen type on photoprotection.
3.) Sunburn and sun protection among young children.
4.) Immunosuppression induced by acute solar-simulated ultraviolet exposure
in humans: prevention by a sunscreen with a sun protection factor of 15 and high UVA protection.
5.) Trends in sun exposure knowledge, attitudes, and behaviors: 1986 to 1996.
6.) Chemoprevention of ultraviolet radiation-induced skin cancer.
7.) Percutaneous absorption of sunscreen agents from liquid paraffin: self-association of octyl salicylate and effects on skin flux.
8.) Skin cancer prevention: a time for action.
9.) Skin type and optimistic bias in relation to the sun protection and suntanning behaviors of young adults.
10.) Broad-spectrum sunscreens provide greater protection against ultraviolet-radiation-induced suppression of contact hypersensitivity to a recall antigen in humans.
11.) Summer sun exposure: knowledge, attitudes, and behaviors of Midwest adolescents.
12.) Immunologic protection afforded by sunscreens in vitro.
13.) Sunscreen lotions prevent ultraviolet radiation-induced suppression of antitumor immune responses.
14.) Multiple chemical sensitivities, including iatrogenic allergic contact
dermatitis, in a patient with chronic actinic dermatitis: implications for management.
15.) Sun-protection behaviour and self-assessed burning tendency among sunbathers.
16.) Skin penetration and sun protection factor of ultra-violet filters from two vehicles.
17.) The sunscreening effect of urocanic acid.
18.) Mexoryl SX protects against solar-simulated UVR-induced photocarcinogenesis in mice.
19.) Sunscreens offer the same UVB protection factors for inflammation and immunosuppression in the mouse.
20.) High-performance liquid chromatographic assay for common sunscreening agents in cosmetic products, bovine serum albumin solution and human plasma.
21.) Oral carotenoid treatment in polymorphous light eruption: a cross-over comparison with oxychloroquine and placebo.
22.) Risk of subsequent basal cell carcinoma and squamous cell carcinoma of the skin among patients with prior skin cancer. Skin Cancer Prevention Study Group.
23.) Topical photoprotection for hereditary polymorphic light eruption of American Indians.
24.) Efficiency of opaque photoprotective agents in the visible light range [see comments]
25.) Photoprotective effect of topically applied superoxide dismutase on sunburn reaction in comparison with sunscreen.
26.) Photoprotective effect of topical anti-inflammatory agents against ultraviolet radiation-induced chronic skin damage in the hairless mouse.
27.) Systemic photoprotective agents.
28.) A mode of action for butylated hydroxytoluene-mediated photoprotection.
29.) In vivo evaluation of photoprotection against chronic ultraviolet-A irradiation by a new sunscreen Mexoryl SX.
30.) Systemic photoprotection.
31.) Evaluation of the photoprotective effect of oral vitamin E supplementation.
32.) Evidence for the photoprotective effects of vitamin E.
33.) Photochemistry and photobiology of urocanic acid.
34.) Determination of UVA protection factors by means of immediate pigment darkening in normal skin.
35.) Broad-spectrum photoprotection: the roles of tinted auto windows, sunscreens and browning agents in the diagnosis and treatment of photosensitivity.
36.) Protective role of butylated hydroxytoluene and certain carotenoids in photocarcinogenesis.
37.) Persistent light reaction. Successful treatment with cyclosporin A.
38.) Comparison of methods for assessing photoprotection against ultraviolet A in
39.) Canthaxanthin.
40.) Disposition and metabolism of topically administered alpha-tocopherol acetate: a common ingredient of commercially available sunscreens and cosmetics.
41.) Synergistic topical photoprotection by a combination of the iron chelator 2-furildioxime and sunscreen.
42.) Topical or oral administration with an extract of Polypodium leucotomos prevents acute sunburn and psoralen-induced phototoxic reactions as well as depletion of Langerhans cells in human skin.
43.) Effectiveness of antioxidants (vitamin C and E) with and without sunscreens as topical photoprotectants.
44.) A review of sunscreen safety and efficacy.
45.) Inhibition of UVB induced DNA photodamage in mouse epidermis by topically applied alpha-tocopherol.
46.) Photoprotection: sunscreens and the immunomodulatory effects of UV irradiation.
47.) Photoprotective and antiinflammatory effects of topical glycolic acid.
48.) Sunscreens used at the beach do not protect against erythema: a new definition of SPF is proposed.
49.) Normal vitamin D levels can be maintained despite rigorous photoprotection: six years' experience with xeroderma pigmentosum.
50.) Decreased p53 expression in chronically sun-exposed human skin after topical photoprotection.
51.) Trends in photoprotection in American fashion magazines, 1983-1993. will fashion make you look old and ugly?
52.) Sunscreens offer the same UVB protection factors for inflammation and immunosuppression in the mouse [see comments]
53.) Microfine zinc oxide (Z-cote) as a photostable UVA/UVB sunblock agent.
54.) Potentials and limitations of the natural antioxidants RRR-alpha-tocopherol, L-ascorbic acid and beta-carotene in cutaneous photoprotection.
55.) Photoprotective actions of natural and synthetic melanins.
56.) Topical melatonin in combination with vitamins E and C protects skin from ultraviolet-induced erythema: a human study in vivo.
57.) Novel function of metallothionein in photoprotection: metallothionein-null mouse exhibits reduced tolerance against ultraviolet B injury in the skin.
58.) The photoprotective effect of 1,25-dihydroxyvitamin D3 on ultraviolet light B-induced damage in keratinocyte and its mechanism of action.
59.) Phototoxic lysis of erythrocytes from humans is reduced after oral intake of ascorbic acid and d-alpha-tocopherol.
60.) Furocoumarin-induced epidermal melanogenesis does not protect against skin photocarcinogenesis in hairless mice.
61.) Melanin.
62.) Photoprotective effect of calcipotriol upon skin photoreaction to UVA and UVB.
63.) [Photosensitizing and photoprotective properties of extracts from groups of medicinal plants].
64.) Electron transfer and photoprotective properties of melanins in solution.
65.) New actions of melatonin and their relevance to biometeorology.
66.) Disposition and metabolism of topically administered alpha-tocopherol acetate: a common ingredient of commercially available sunscreens and cosmetics.
67.) [Polymorphic light dermatitis. Photobiology and photoprotection].
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===================================================================
1.) Sun Smart Day: a pilot program for photoprotection education.
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Buller MK; Goldberg G; Buller DB
Behavioral Sciences Section, Arizona Cancer Center, Tucson 85719, USA.
Pediatr Dermatol (UNITED STATES) Jul-Aug 1997 14 (4) p257-63 ISSN:
0736-8046
Contract/Grant No.: CA23074--CA--NCI
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9711
Subfile: INDEX MEDICUS
Excessive exposure to the sun's ultraviolet radiation (UVR) contributes
to the
etiology of melanoma and nonmelanoma skin cancers. Many behaviors that
increase
lifetime risk of skin cancer--sun exposure, sunburn, and lack of sun
protection--
occur early in childhood. A 1-day school-based skin cancer prevention
effort--Sun
Smart Day--was implemented and evaluated in three elementary schools to
improve
fourth-graders' knowledge, attitudes, and behaviors related to skin cancer
prevention.
A classroom-based skin cancer prevention lesson was compared to an
interactive sun
safety fair was vehicles for promoting comprehensive photoprotection. Sun
Smart Day
interventions had their greatest impact on fourth-graders' awareness and
knowledge of
skin cancer and children's increased knowledge persisted through the summer
break.
While both the classroom curriculum and the health fair boosted awareness and
knowledge of sun safety among fourth graders, the classroom curriculum
demonstrated a
slight immediate advantage over the health fair on these outcomes. Also the
curriculum was less difficult to implement, but the health fair was more
engaging. A
Sun Smart Day program may be an important first step in increasing public
awareness
and understanding of skin cancer and its prevention.
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2.) The influence of sunscreen type on photoprotection.
===================================================================
Diffey BL; Grice J
Regional Medical Physics Department, Dryburn Hospital, Durham, U.K.
Br J Dermatol (ENGLAND) Jul 1997 137 (1) p103-5 ISSN: 0007-0963
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9711
Subfile: INDEX MEDICUS
Twenty-five volunteers took part in this study whose aims were to
determine whether
there was any difference between the applied amounts of a chemical and
physical
sunscreen of the same sun protection factor (SPF); whether the SPF of a
chemical
sunscreen influenced the quantity applied; and whether individuals who
burnt easily
in sunlight tended to apply more sunscreen than those who tolerated sun
exposure. We
found that most subjects choose to apply about two-thirds the quantity of
physical
compared with chemical sunscreen. This reduction in amount applied is
likely to
lead, in practice, to the physical sunscreen providing a SPF of about
one-half of
that achieved with the chemical sunscreen. In sunscreens in which the only
variation
was the concentration of the active organic chemical absorbers (and hence
SPF), there
was no difference in the amount of sunscreen applied and so the protection
afforded
can be assumed to increase in line with the SPF. While there was no
statistically
significant difference between the amounts applied by subjects of different
skin
types, there was a tendency for subjects with the lower skin types to apply
more
sunscreen than those who burnt less easily.
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3.) Sunburn and sun protection among young children.
===================================================================
McGee R; Williams S; Glasgow H
Department of Preventative and Social Medicine, University of Otago
Medical School,
Dunedin, New Zealand.
J Paediatr Child Health (AUSTRALIA) Jun 1997 33 (3) p234-7 ISSN:
1034-4810
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9711
Subfile: INDEX MEDICUS
OBJECTIVE: To examine the extent of sun exposure, sun protection and
experience of
sunburn among young New Zealand children on summer weekends. METHODS: In a
telephone
survey of 1243 respondents, those with children in the household were asked
about sun
exposure and protection for the youngest child in the family. Information
was
obtained for 285 children aged from infancy to 10 years. RESULTS: Over 90%
of the
children were reported to be outside on the preceding Saturday and/or
Sunday; 7% of
those outside experienced some degree of sunburn. The worst burning was on
the face,
head, neck or ears. On either day about half the children were wearing
sunscreen and
60% were wearing a hat. Parental use of sun protection was the strongest
predictor
of sun protection among the children. CONCLUSIONS: While reports of sun
protection
among young children were encouraging, many children in the community are
still at
high risk of sunburn. Efforts to promote sun protection as a family
responsibility
may reduce the experience of burning among the young.
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4.) Immunosuppression induced by acute solar-simulated ultraviolet exposure in humans: prevention by a sunscreen with a sun protection factor of 15 and high UVA protection.
===================================================================
Serre I; Cano JP; Picot MC; Meynadier J; Meunier L
Laboratory of Drug Toxicology, University of Montpellier, France.
J Am Acad Dermatol (UNITED STATES) Aug 1997 37 (2 Pt 1) p187-94 ISSN:
0190-9622
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9711
Subfile: INDEX MEDICUS
BACKGROUND: Cutaneous exposure to UVB radiation impairs the induction of
contact
hypersensitivity (CHS). Variable results have been found among studies
examining the
use of sunscreens to prevent UV-induced immunosuppression. OBJECTIVE: Our
purpose
was to determine whether solar-simulated exposure of human skin resulted in
an
impairment of CHS responses and whether the preapplication of an
intermediate sun
protection factor (SPF) sunscreen could prevent this locally UV-induced
immunosuppression. METHODS: Irritant and CHS responses to
dinitrochlorobenzene
(DNCB) were randomly assessed in 160 human volunteers with or without UV
exposure and
with or without prior application of an SPF 15 sunscreen with high UVA
protection.
DNCB sensitization was performed 3 days after acute UV irradiation
corresponding to 3
minimal erythema doses. RESULTS: After solar-simulated UV exposure, the
percentage
of positive responses to DNCB sensitization dropped from 95% to 50% (p =
0.003).
Prior application of the sunscreen formulation did not modify the
percentage of
positive responses (90%) and maintained the immunization rate at 85% among
volunteers
exposed to UV. CONCLUSION: A localized sunburn can impair the afferent arm
of CHS
reactions in humans. The use of intermediate SPF sunscreens with high UVA
protection
adequately protects from the suppression of CHS responses that occurs after
acute
solar-simulated UV exposure.
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5.) Trends in sun exposure knowledge, attitudes, and behaviors: 1986 to 1996.
===================================================================
Robinson JK; Rigel DS; Amonette RA
Northwestern University Medical School, Department of Dermatology,
Chicago, IL
60611, USA.
J Am Acad Dermatol (UNITED STATES) Aug 1997 37 (2 Pt 1) p179-86 ISSN:
0190-9622
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9711
Subfile: INDEX MEDICUS
BACKGROUND: The American Academy of Dermatology's national program
Melanoma/Skin
Cancer Detection and Prevention, developed in response to the rising
incidence of
invasive melanoma in the United States, has annually during the past decade
produced
extensive print, radio, and television coverage about the dangers of sun
exposure and
benefits of sun protection. OBJECTIVE: We measured the progress achieved in
increasing the awareness and knowledge of skin cancer and changing the
attitudes,
beliefs, and behaviors that affect skin cancer risk. We also describe
current sun-
related behavior including sunburning, assess the likelihood of practicing
sun
protection strategies, and provide a baseline against which future changes
in sun
protection behavior may be evaluated. METHODS: A 1996 telephone survey
repeated
questions used in 1986 to evaluate change and used classifying questions to
better
define attitudes and behaviors. RESULTS: From 1986 to 1996, the knowledge
of the
perceived harmful effects of the sun significantly broadened, but the UV
exposure
behavior as measured by sunburning (30% to 39%) and regular use of a
tanning booth
(2% to 6%) also increased. There was a decline in the attitude that having
a tan was
healthy; however, in 1996 having a tan was still considered to enhance
appearance,
particularly by men. Sunscreen use increased (35% to 53%). Women, younger
persons,
persons residing in areas with fewer sunny days, and whites were more
likely to tan
intentionally, but men who lived in the South were more likely to sunburn.
CONCLUSION: During the past decade, the early process of change involving
cognitive
and emotional activities began. With this study, high-risk population
subsets
performing specific adverse behavior were identified. In the future, they
can be
targeted with messages that promote attitudinal and behavioral change.
===================================================================
6.) Chemoprevention of ultraviolet radiation-induced skin cancer.
===================================================================
Ley RD; Reeve VE
Photomedicine Program, Lovelace Institutes, Albuquerque, New Mexico
87106, USA.
[email protected]
Environ Health Perspect (UNITED STATES) Jun 1997 105 Suppl 4 p981-4
ISSN: 0091-
6765
Language: ENGLISH
Document Type: JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL
Journal Announcement: 9711
Subfile: INDEX MEDICUS
The use of chemical and physical sunscreening agents has increased
dramatically
during the last two to three decades as an effective means of preventing
sunbum. The
use of high sunprotection factor sunscreens has also been widely promoted
for the
prevention of skin cancer, including melanoma. Whereas sunscreens are
undoubtedly
effective in preventing sunbum, their efficacy in preventing skin cancer,
especially
melanoma, is currently under considerable debate. Sunscreens have been
shown to
prevent the induction of DNA damage that presumably results from the direct
effects
of ultraviolet radiation (UVR) on DNA. DNA damage has been identified as an
initiator of skin cancer formation. However, both laboratory and
epidemiological
studies indicate that sunscreens may not block the initiation or promotion of
melanoma formation. These studies suggest that the action spectrum for
erythema
induction is different than the action spectrum for the induction of
melanoma.
Indeed, recent reports on the wavelength dependency for the induction of
melanoma in
a fish model indicate that the efficacy of ultraviolet A wavelengths
(320-400 nm) to
induce melanoma is orders of magnitude higher than would be predicted from
the
induction of erythema in man or nonmelanoma skin tumors in mice. Other
strategies
for the chemoprevention of skin cancer have also been reported. Low levels
and
degree of unsaturation of dietary fats protect against UVR-induced skin
cancer in
mice humens. Compounds with antioxidant activity, including green tea
extracts
(polyphenols), have been reported to inhibit UVR-induced skin
carcinogenesis. (50
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7.) Percutaneous absorption of sunscreen agents from liquid paraffin: self-association of octyl salicylate and effects on skin flux.
===================================================================
Jiang R; Roberts MS; Prankerd RJ; Benson HA
School of Pharmacy, University of Queensland, St. Lucia, Brisbane,
Australia.
J Pharm Sci (UNITED STATES) Jul 1997 86 (7) p791-6 ISSN: 0022-3549
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9711
Subfile: INDEX MEDICUS
This study provides an investigation of the availability of octyl
salicylate (OS),
a common sunscreen agent, from liquid paraffin and the effect of OS on skin
permeability. A model membrane system to isolate the vehicle effect from
membrane
permeability has been developed. Partitioning of OS between liquid
paraffin and
aqueous receptor phases was conducted. Partition coefficients increased with
increase in OS concentration. A range of OS concentrations in liquid
paraffin was
diffused across human epidermis and synthetic membranes into 4% bovine
serum albumin
in phosphate-buffered saline and 50% ethanol. Absorption profiles of OS
obtained
from silicone and low-density polyethylene (LDPE) membranes were similar to
each
other but higher than for the high-density polyethylene [HDPE (3 times)]
membrane and
human epidermis (15 times). The steady state fluxes and apparent
permeability
coefficients (Kp') obtained from the diffusion studies showed the same
trends with
all membranes, except for the HDPE membrane which showed greater increase
in flux and
Kp' at concentrations above 30%. IR spectra showed that several bands of
OS were
shifted with concentrations, and the molecular models further suggested
that the main
contribution to the self-association is from non-1,4 van der Waals
interactions.
===================================================================
8.) Skin cancer prevention: a time for action.
===================================================================
Everett SA; Colditz GA
Harvard Center for Cancer Prevention, Harvard School of Public Health,
Boston, MA,
USA.
J Community Health (UNITED STATES) Jun 1997 22 (3) p175-83 ISSN:
0094-5145
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9710
Subfile: INDEX MEDICUS
Skin cancer is the most common malignancy in the United States accounting
for more
than 840,000 cases and 9,400 deaths annually. It is estimated that 90% of
non-
melanoma skin cancers and much of melanoma incidence can be attributed to sun
exposure. The evidence suggests that regular use of sunscreen (Sun
Protective Factor
(SPF) of 15 or higher), wearing protective, tightly woven clothing and wide
brimmed
hats, and avoiding sun exposure when the ultraviolet rays are strongest
(between
11:00 a.m. and 3:00 p.m.) can dramatically reduce the risk of skin cancer.
Interventions to promote sun-protection behaviors that target children and
adults are
necessary to reduce the growing incidence rate of skin cancer in the United
States.
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9.) Skin type and optimistic bias in relation to the sun protection and suntanning behaviors of young adults.
===================================================================
Clarke VA; Williams T; Arthey S
School of Psychology, Deakin University, Geelong, Victoria, Australia.
J Behav Med (UNITED STATES) Apr 1997 20 (2) p207-22 ISSN: 0160-7715
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9710
Subfile: INDEX MEDICUS
The study examined the roles of general and personal beliefs and skin
type in
relation to suntanning and sun protection, by assessing various perceptions
of risk
of skin cancer both for the self and for the average person. A sample of
355 people
aged 16 to 25 years was selected randomly from the telephone directory of a
coastal
provincial city. Highly structured interviews were conducted over the
telephone.
The findings were presented in relation to three research questions.
First, skin
type, classified as burn only, burn then tan, or tan without burning,
influenced both
general and personal beliefs. Compared to the tan-only group, the
burn-only group
perceived earlier age at onset, greater number of years of life lost, and
greater
severity of skin cancer, for both the average person and the self, and
greater
susceptibility to skin cancer for the average person. Second, differences
were found
between personally relevant and population-relevant beliefs on
susceptibility to skin
cancer, time of onset, and years of life lost due to skin cancer but not for
perceptions of severity and curability. Finally, skin cancer beliefs were
poor
correlates of tanning and protecting behaviors. The factor explaining the
greatest
proportion of variance in both behaviors was skin type.
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10.) Broad-spectrum sunscreens provide greater protection agains tultraviolet-radiation-induced suppression of contact hypersensitivity to a recall antigen in humans.
===================================================================
Damian DL; Halliday GM; Barnetson RS
Department of Medicine (Dermatology), University of Sydney at Royal
Prince Alfred
Hospital, Australia.
J Invest Dermatol (UNITED STATES) Aug 1997 109 (2) p146-51 ISSN:
0022-202X
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9710
Subfile: INDEX MEDICUS
This study investigates the extent to which sunscreens protect humans from
ultraviolet (UV)-radiation-induced immunosuppression. In the presence of
solar-
simulated UV, three sunscreens with differing UVA transmission were
assessed for
their ability to protect the contact hypersensitivity (CHS) response to
nickel of 16
nickel-allergic subjects. The sunscreens contained 2-ethylhexyl para-
methoxycinnamate (cinnamate), cinnamate with oxybenzone, or cinnamate with
zinc
oxide, respectively. All had sun protection factors of 10 and hence
inhibited UV
erythema to similar extents. Volunteers were irradiated on their backs with
suberythemal UV daily for 5 d after application of the sunscreens and their
base
lotion to different sites. Nickel-containing patches were then applied to
both UV-
treated sites and adjacent, unirradiated control sites. Erythema caused by
nickel
CHS at each site was quantitated 72 h later with a reflectance erythema
meter. In
comparison of the nickel reactions of irradiated and unirradiated skin,
there was 35%
mean immunosuppression in unprotected UV-treated skin. Significant
immunosuppression
also occurred at sites irradiated through the narrow-spectrum cinnamate-only
sunscreen but was prevented by the two broad-spectrum sunscreens. To
determine
whether UV-induced suppression of the nickel response is specific for
cell-mediated
immunity or reflects suppression of nonspecific inflammation, a further 16
subjects
were patch-tested with a skin irritant, sodium lauryl sulfate (SLS),
following a
sunscreen and irradiation protocol identical to that of the nickel
volunteers. UV
had no significant effect on SLS responses. We conclude that nickel patch
testing is
a valid means of assessing UV-induced immunosuppression in humans and that
even with
suberythemal UV, immune protection was provided only by sunscreens
filtering both UVA
and UVB.
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11.) Summer sun exposure: knowledge, attitudes, and behaviors of Midwest
adolescents.
===================================================================
Robinson JK; Rademaker AW; Sylvester JA; Cook B
American Cancer Society, Illinois Division, Inc., Chicago 60603, USA.
Prev Med (UNITED STATES) May-Jun 1997 26 (3) p364-72 ISSN: 0091-7435
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9709
Subfile: INDEX MEDICUS
BACKGROUND: Extensive print, radio, and television coverage about the
dangers of
sun exposure and benefits of sun protection occurred over the past decade.
Illinois
teen knowledge and attitudes about sun exposure/protection,
sun-exposure/protection
behavior, and information sources were determined by a summer telephone
survey.
METHODS: Telephone interviews with 658 teenagers between ages 11 and 19
included
African-American, Asian, Hispanic, Native American, and white teenagers.
RESULTS:
Teens knew that too much sun was harmful as it caused skin cancer and
sunburn.
Sunburn was mentioned more often by those with skin types that burned
easily and
tanned poorly (I,II) (P < 0.001), was better known to girls than to boys (P
< 0.001),
and was recognized more by those with higher socioeconomic status (P <
0.001) but was
not associated with age. Widely held sun exposure attitudes were
socializing with
friends and feeling better when outdoors. On weekdays, boys averaged 5.3
hr (SD,
1.65 hr) outside compared with 3.9 hr (SD, 0.75 hr) for girls (P < 0.001).
Teenage
boys were more likely to obtain occupational sun exposure, and girls
sunbathed.
Subjects with skin types I and II reported an average of 3.3 sunburns in
the past
year. During unprotected sun exposure, extensive numbers of teens with
moderate-risk
skin type experienced at least 1 sunburn per year. Indoor tanning use was
more
prevalent among older girls and those with skin types I and II. Sunscreen
use was
associated with water recreational activities (swimming, water sports, and
going to
the beach) by girls slightly more than by boys (P < 0.001). Hat-wearing
was more
common among boys than among girls. CONCLUSIONS: Teen knowledge that
excessive sun
exposure causes skin cancer and sunburns and that wearing sunscreens and
hats were
sun-protective methods did not enable sun protection that prevented
burning. This is
particularly troublesome because severe sunburns in youth are associated
with an
increased risk of melanoma. Existing teen sunscreen use could be broadened
by
educating teens to use adequate quantities of sunscreen prior to daily sun
exposure
to prevent painful burns. Messages to teens that emphasize the short-term
consequence of painful sunburns because of inadequate protection during
outdoor
occupational and non-water-related recreational exposure would increase the
relevance
of the message and may enable behavioral change. Parents and physicians
need to be
included in messages that are directed to teens and to become part of their
education.
Parents could ensure an adequate sunscreen supply for daily use by the
family,
encourage teens not to deliberately tan, and serve as role models for the
use of
protective clothing.
===================================================================
12.) Immunologic protection afforded by sunscreens in vitro.
===================================================================
Davenport V; Morris JF; Chu AC
Department of Medicine, Royal Postgraduate Medical School, London, UK.
J Invest Dermatol (UNITED STATES) Jun 1997 108 (6) p859-63 ISSN:
0022-202X
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9709
Subfile: INDEX MEDICUS
Several studies have suggested a lack of correlation between sunscreen sun
protection factor and protection of the skin immune system, potentially
allowing
greater damage to the skin by removing the natural protective erythemal
response to
sun exposure. Despite this, routine testing of immune protection afforded by
sunscreens is not performed by industry. Current laboratory methods for
investigating the efficacy of sunscreen protection of epidermal immune
function use
the induction of contact hypersensitivity or epidermal cell alloantigen
presentation.
Animal models, cell culture systems, and in vivo human studies are commonly
employed,
but all these systems have significant drawbacks for use in routine
testing. The
purpose of this study was to develop an in vitro system for testing the
immunologic
protection afforded by sunscreens in human skin. Five test sunscreens plus
a vehicle
control were tested in a "blind" fashion for their in vitro level of immune
protection. Creams were applied in a standard manner to human whole skin
explants
and were irradiated over a range of physiologic doses using an Oriel solar
simulator.
A mixed epidermal lymphocyte reaction was used to quantify epidermal
alloantigen-
presenting capacity, in the presence or absence of test cream, for five
explants.
Results consistently demonstrated that all the test sunscreens protected
beyond their
designated sun protection factors, whereas the vehicle conferred no
protection. The
explant-mixed epidermal lymphocyte reaction system gave consistent,
reproducible
results and may prove useful for the allocation of an immune protection
factor to all
sunscreens.
===================================================================
13.) Sunscreen lotions prevent ultraviolet radiation-induced suppression of
antitumor immune responses.
===================================================================
Roberts LK; Beasley DG
Department of Research and Development, Schering-Plough HealthCare
Products,
Memphis, TN 38151, USA. [email protected]
Int J Cancer (UNITED STATES) Mar 28 1997 71 (1) p94-102 ISSN: 0020-7136
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9707
Subfile: INDEX MEDICUS
Exposure to subcarcinogenic doses of ultraviolet (UV) radiation
suppresses tumor
immunity, thus permitting the emergence and growth of highly immunogenic
skin cancers
in mice. Sunscreens prevent UV carcinogenesis; however, there are
conflicting
reports regarding their ability to block UV-induced tumor immune
suppression. In
this study we critically evaluated the effects of UV spectrum and dose on
the tumor
immune protective capacity of 4 marketed sunscreen lotions with labeled sun
protection factors (SPF) 8-45. Effective tumor immune suppression doses
(TISD),
i.e., the lowest dose tested to induce outgrowth of transplanted
nonmelanoma skin
tumors in 100% of UV-exposed C3H mice, were established for 3 different UV
sources.
TISD were significantly lower for unfiltered (FS) and Kodacel-filtered
(KFS) UVB-type
FS20 sunlamps compared with a filtered xenon arc lamp solar simulator.
Sunscreen
tumor immune protection levels matched those predicted by their labeled SPF
when
sunscreen-protected mice were exposed to a fixed TISD of solar simulator UV
radiation.
SPF 30 and 45 sunscreens also blocked activation of tumor antigen-specific
suppressor
T-lymphocytes in mice exposed to solar simulator UV radiation. In
comparison,
sunscreens with SPF > or = 15 provided partial to complete protection, as
measured by
tumor incidence, for mice exposed to UV radiation from KFS. All sunscreens
tested
reduced tumor growth rates in KFS UV-exposed mice. None of the sunscreens
tested
provided measurable tumor immune protection for mice exposed to FS UV
radiation.
Thus, sunscreen lotions provide an extent of tumor immune protection
consistent with
their labeled SPF when appropriate testing conditions are employed.
===================================================================
14.) Multiple chemical sensitivities, including iatrogenic allergic contact
dermatitis, in a patient with chronic actinic dermatitis: implications
for management.
===================================================================
Stitt WZ; Scott GA; Martin RE; Gaspari AA
Department of Dermatology, University of Rochester School of Medicine and
Dentistry, NY, USA.
Am J Contact Dermat (UNITED STATES) Sep 1996 7 (3) p166-70 ISSN:
1046-199X
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9706
Subfile: INDEX MEDICUS
BACKGROUND: Chronic actinic dermatitis represents a spectrum of
photosensitive
dermatoses. Phototesting and photopatch testing are necessary to elucidate
the
specific subtype. Such patients may have multiple cutaneous allergies and
photoallergies. OBJECTIVE: This is a case report of a patient with chronic
actinic
dermatitis whose condition was worsened by certain sunscreens and
corticosteroids.
Our purpose was to identify the specific subtype of chronic actinic
dermatitis and
cutaneous allergens. METHODS: Phototesting to UVB and UVA was performed.
Photopatch
testings to standard photoallergens and to Photoplex sunscreen ingredients
was
performed. Patch testing to standard allergens and proprietary
corticosteroids was
performed. RESULTS: Positive photoallergies to Photoplex sunscreen and the
UVA
screen within Photoplex, Parsol 1789
(4-tert-butyl-4'-methoxydibenzoyl-methane), were
identified. Positive allergies to Aclovate (alclometasone dipropionate)
cream and
ointment and Locoid (hydrocortisone butyrate) ointment were identified.
The patient
showed increased UVB sensitivity. CONCLUSION: This is a case report of a
patient
with chronic actinic dermatitis. A relevant photoallergy to Parsol 1789 and
corticosteroid sensitivities to aclometasone and hydrocortisone butyrate were
identified. Multiple cutaneous allergens may be identified in patients
with chronic
actinic dermatoses, and avoidance of known allergens may result in
significant
improvement of the chronic dermatitis.
===================================================================
15.) Sun-protection behaviour and self-assessed burning tendency among
sunbathers.
===================================================================
Stender IM; Lock-Andersen J; Wulf HC
Department of Dermatology, National University Hospital, Rigshospitalet,
Copenhagen, Denmark.
Photodermatol Photoimmunol Photomed (DENMARK) Aug 1996 12 (4) p162-5
ISSN: 0905-
4383
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9706
Subfile: INDEX MEDICUS
A total of 805 sunbathing Caucasians were interviewed about sunprotection
behaviour
and self-assessed burning tendency. Sixty-seven percent of the interviewed
sunbathers used one or more sunscreen factors. Sunscreen-users and
nonusers were
exposed to the sun 206 min and 197 min (P = 0.186), respectively. The
sunscreen
users were exposed to a marginally higher UV dose than non-sunscreen users,
4.8 SED
versus 4.5 SED (P = 0.0348). The rate of sunscreen users was significantly
higher
among subjects who stated that they always were sunburnt in the spring when
not using
a sunscreen than subjects who stated that they never were sunburnt in the
spring when
not using a sunscreen (P = 0.0001). However, when comparing subjects that
always
burn in the spring and subjects that never burn in the spring, we found no
significant difference between level of the sun-protection factor (P =
0.11) nor the
duration of sun exposure (P = 0.967), nor to which UV doses the subjects
were exposed
(P = 0,562). Furthermore we found that the interviewed sunbathers
interpreted to "be
sunburnt" as more severe than "to turn red". Public campaigns recommend
the use of
sun protection cream when sunbathing without using other sun protective
strategies;
however, the use of sun protection cream is inadequate among sunbathers.
More
education is required to persuade those with more sun-sensitive skin to use
a higher
protection-factor, to reduce sun exposure at times when UV radiation is
most intense,
and to reduce the duration of exposure.
===================================================================
16.) Skin penetration and sun protection factor of ultra-violet filters from two
vehicles.
===================================================================
Treffel P; Gabard B
Department of Biopharmacy, Spirig AG, 4622 Egerkingen, Switzerland.
Pharm Res (UNITED STATES) May 1996 13 (5) p770-4 ISSN: 0724-8741
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9705
Subfile: INDEX MEDICUS
PURPOSE. In order to improve our knowledge on the efficacy and safety of
sunscreen
products, we measured the skin penetration profiles of ultra-violet (UV)
filters in
vitro and in vivo, and the corresponding sun protection factors (SPF) from
two
vehicles (an O/W emulsion-gel and petroleum jelly). METHODS. The UV
filters tested
were oxybenzone (5%, A), 2-ethylhexyl 4-methoxycinnamate (7.5%,B), and 2-
ethylhexylsalicylate (3%,C). Two mg/cm(2) were applied for 2 min to 6 h.
In vitro
penetration measurements were performed with static diffusion cells. In
vivo, horny
layer concentrations were measured after stripping and the SPF evaluated as
recommended by the COLIPA-guidelines. RESULTS. Significant differences
between
vehicles were noticed in vitro as well as in vivo. In vitro, the
emulsion-gel
generated higher epidermal concentrations than petroleum jelly. Values at
6 h,
expressed as percent of the applied dose for A, B, and C were 4, 9, and 7%
for the
emulsion-gel and 2, 1, and 2% for petroleum jelly. An opposite trend was
noticed,
mainly for A, in the deeper skin layers with concentrations of 2% in the
dermis and
5% in the receptor fluid for petroleum jelly and 0.6% and 1% for the
emulsion-gel
respectively. In vivo, for each UV filter, maximal stratum corneum levels
(15
strips) were obtained at 0.5 h with percentages of the applied doses of 50%
for the
emulsion-gel and 15 percent for petroleum jelly. SPFs, measured 0.5 h after
application amounted to 14 for the emulsion-gel and 5 for petroleum jelly,
and
decreased in both cases by a factor 2.2 after removal of non penetrated
product.
CONCLUSIONS. These preliminary results demonstrated that UV filters
penetration and
retention as well as expected SPF could be optimized by a suitable vehicle.
===================================================================
17.) The sunscreening effect of urocanic acid.
===================================================================
de fine Olivarius F; Wulf HC; Crosby J; Norval M
Department of Dermatology, Rigshospitalet, University Hospital, Copenhagen,
Denmark.
Photodermatol Photoimmunol Photomed (DENMARK) Jun 1996 12 (3) p95-9
ISSN: 0905-
4383
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9705
Subfile: INDEX MEDICUS
Urocanic acid (UCA), present in the stratum corneum, is a major absorber of
ultraviolet (UV) radiation and, on UV exposure, is induced to isomerize
from the
naturally occurring trans-isomer to the cis-isomer. Cis-UCA has been shown
to have
immunosuppressive properties, while trans-UCA may act as a natural
sunscreen due to
its UV-absorbing properties. The photoprotective capacity of UCA was
investigated in
this study. Minimal erythema dose (MED) was determined on normal buttock
skin in 36
healthy subjects and the concentration of UCA isomers was measured on the
skin
adjacent to the test site. On the contralateral buttock. MED was
determined 20 min
after application of trans-UCA 5% in a cream base. The UCA cream gave a sun
protection factor of 1.58. The amount of UCA applied was, however, 20-200
times
higher than the amount of UCA found in normal skin, making a sunscreening
effect of
naturally occurring UCA very low. This was further supported, by a lack of
correlation between naturally occurring UCA and the UV sensitivity of each
subject
determined by the MED.
===================================================================
18.) Mexoryl SX protects against solar-simulated UVR-induced
photocarcinogenesis in mice.
===================================================================
Fourtanier A
L'Oreal, Centre de Recherche Charies Zviak, Recherche Avancee, Clichy,
France.
Photochem Photobiol (UNITED STATES) Oct 1996 64 (4) p688-93 ISSN:
0031-8655
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9704
Subfile: INDEX MEDICUS
The aim of this study was to determine, for regulatory purposes, the
potential of
Mexoryl SX, a broad UVA absorber that also absorbs to some extent in the
UVB, to
modify the UV radiation (UVR)-induced murine skin tumor development and
growth. Skh-
hr1 mice were exposed to solar-simulated UVR 5 days per week for 40 weeks.
Two
control groups were irradiated without topical application, three groups
received a
sunscreen preparation containing either the UVA absorber, Mexoryl SX at 5
or 10%
concentration, or a filter that absorbs principally in the UVB,
2-ethylhexyl-p-
methoxycinnamate (2-EHMC) at 5% concentration, introduced as a comparator
test
article. Sunscreen application was performed before UVR exposure 3 days
per week and
after UVR exposure on the other 2 days (consistent with the design of a
standard
photocarcinogenesis safety test). Two different weekly UVR doses were
administrated:
the lower dose was given to one group of unprotected animals, whereas the
higher dose
was administrated to the other unprotected group and to the three
sunscreen-treated
groups. The two UVR control groups demonstrated a UVR-dependent response for
cumulative tumor prevalence, tumor yield and median latent period. Neither
concentration of Mexoryl SX increased the probability of tumor development;
consistent with the principles for safety testing, this provides evidence
in that it
is safe for use in sunlight. Although this study was explicitly designed
as a safety
test, the results also provide some clues about the efficacy of Mexoryl SX in
decreasing the probability of tumor development. Topical administration of
Mexoryl
SX, at both concentrations, resulted in a 6 week delay in the median latent
period
compared to high UVR controls, whereas 5% 2-EHMC delayed the median latent
periods
only by 2 weeks. Tumor prevalence and yield show the same efficacy
differences
between the two sunscreen ingredients. Tumor protection factors were
calculated from
these results and found to be equal to 2.4 for the two preparations
containing
Mexoryl SX and to 1.3 for the 5% 2-EHMC preparation. These findings
illustrate the
efficacy of Mexoryl SX in preventing UVR-induced carcinogenesis.
===================================================================
19.) Sunscreens offer the same UVB protection factors for inflammation and
immunosuppression in the mouse.
===================================================================
Walker SL; Young AR
Department of Photobiology, St. John's Institute of Dermatology, United
Medical and
Dental Schools of Guy's and St Thomas's Hospital, University of London, U.K.
J Invest Dermatol (UNITED STATES) Feb 1997 108 (2) p133-8 ISSN:
0022-202X
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9704
Subfile: INDEX MEDICUS
Many studies report that sunscreens effective against UVR-induced
inflammation
afford poor protection against immunosuppression. We have studied the
relationship
between photoprotection of inflammation and immunosuppression with
monochromatic UVB
(Philips TL01 tubes, lambda max = 311 nm) to remove possible confounding
effects of
differences in end point action spectra. Dose-response curves for edema
and systemic
suppression of contact hypersensitivity (CHS) in HRA.HRII-c/+/Skh mice
showed that
suppression of CHS was more sensitive to UVB irradiation by a factor of 2.
The UVB
dose-response curve for murine edema was similar to that for human
erythema, with
threshold doses of 773 mJ x cm(-2) and 632 mJ x cm(-2), respectively. The
protection
afforded by two UVB filters, octyl dimethyl para-aminobenzoic acid and
2-ethylhexyl-
4'-methoxycinnamate, prepared in an identical vehicle, each with the same
optical
density at 311 nm, was tested in mice. We applied sunscreen to all exposed
skin or
to transpore tape above the irradiation cages, prior to exposure with 2.8
minimal
edema doses. Topical or tape application of both sunscreens protected
totally
against edema but only partially against immunosuppression, with no
significant
difference in protection between the two application techniques (p > 0.4). A
sunscreen protection factor of 4 in vivo was determined for 2-ethylhexyl-4'-
methoxycinnamate for both edema and immunosuppression. Failure of the
sunscreens to
protect completely against immunosuppression was due to the ability of
subedemal
doses of UVB to induce substantial immunosuppression and not, as previously
suggested, to any skin interaction.
===================================================================
20.) High-performance liquid chromatographic assay for common sunscreening
agents in cosmetic products, bovine serum albumin solution and human plasma.
===================================================================
Jiang R; Hayden CG; Prankerd RJ; Roberts MS; Benson HA
Department of Pharmacy, University of Queensland, St. Lucia, Australia.
J Chromatogr B Biomed Appl (NETHERLANDS) Jun 28 1996 682 (1) p137-45
ISSN: 0378-
4347
Language: ENGLISH
Document Type: JOURNAL ARTICLE
Journal Announcement: 9704
Subfile: INDEX MEDICUS
This paper reports the development of a reversed-phase high-performance
liquid
chromatographic assay for quantifying five of the most common sunscreen
agents,
namely 2-ethylhexyl-p-dimethyl aminobenzoate (Escalol 507), 2-ethylhexyl-p-
methoxycinnamate (Parsol MCX); 4-tert.-butyl-4'-methoxydibenzoylmethane
(Parsol
1789), 2-hydroxy-4-methoxybenzophenone-3 (oxybenzone) and
2-ethylhexyl-salicylate
(octylsalicylate). The assay permits analysis of the sunscreen agents in
formulations and in biological fluids, including bovine serum albumin (BSA)
solution,
a common additive to in vitro skin diffusion cell receptor fluids, as well
as human
plasma. Separation was achieved using an ODS C154 column with a
methanol-water
(88:12) mobile phase. The analytes were detected by ultraviolet light
absorption at
a wavelength of 315 nm. The assay was linear with minimum detectable limits,
calculated as greater than 3-times the baseline noise level: for oxybenzone
and
Escalol 507, 0.05 microgram/ml; for Parsol 1789 and Parsol MCX, 0.1
microgram/ml; for
octylsalicylate, 1 microgram/ml. Recoveries from both plasma and 2% BSA
were within
the range 89-107%. The inter- and intra-day coefficients of variation for
the five
agents were not more than 4% at the upper end of the linear range and not
more than
10% at the lower end. Preliminary stability studies of the sunscreen
agents in a
commercial product and in two diffusion cell receptor fluids were also
conducted.
===================================================================
21.) Oral carotenoid treatment in polymorphous light eruption: a cross-over comparison with oxychloroquine and placebo.
===================================================================
ARTICLE SOURCE: Photodermatol (Denmark), Jun 1985, 2(3) p166-9
AUTHOR(S): Jansen CT
ABSTRACT: During 3 consecutive summers, patients from a total group of 40 persons with polymorphous light eruptions (PMLE) participated in a randomized, double-blind, cross-over study comparing the sun-protective effect of placebo capsules, a chloroquine derivative (200 mg daily of oxychloroquine), and a carotenoid preparation (betacarotene and canthaxanthine in a daily total dose of 100 mg). A total of 35 carotenoid, 38 chloroquine, and 27 placebo treatment periods were registered. Full freedom from sun sensitivity was obtained during 6 carotenoid and 8 chloroquine periods, but never with placebo treatment. In addition, a partial sun tolerance was induced in 17 carotenoid periods, 15 chloroquine periods, and in 14 placebo treatment periods.
===================================================================
22.) Risk of subsequent basal cell carcinoma and squamous cell carcinoma of the skin among patients with prior skin cancer. Skin Cancer Prevention Study Group.
===================================================================
ARTICLE SOURCE: JAMA (United States), Jun 24 1992, 267(24) p3305-10
AUTHOR(S): Karagas MR; Stukel TA; Greenberg ER; Baron JA; Mott LA; Stern RS
PUBLICATION TYPE: CLINICAL TRIAL; JOURNAL ARTICLE; RANDOMIZED CONTROLLED TRIAL
ABSTRACT: OBJECTIVE--The primary aims of this study were to assess risk of subsequent basal and squamous cell skin cancer among patients with a prior history of these tumors and to examine these risks in relation to patient characteristics and life-style factors. DESIGN--Follow-up of participants in a randomized trial of betacarotene as a possible skin cancer preventive agent. SETTING--Clinical centers in Los Angeles, Calif, San Francisco, Calif, Minneapolis, Minn, and Hanover, NH. PARTICIPANTS--Patients (n = 1805) who were diagnosed as having a basal or squamous cell skin cancer between January 1980 and February 1986 and were free of skin cancer at study entry. MAIN OUTCOME MEASURE--Time from study entry to first new occurrence of basal and squamous cell skin cancer. RESULTS--The estimated risk of developing one or more new skin cancers was 35% at 3 years and 50% at 5 years. New skin cancers tended to be of the same cell type as the previous skin cancers. For both basal and squamous cell skin cancer, risk was higher among patients who were male, were over the age of 60 years, had more prior skin cancers, had severe actinic skin damage, or who burned easily with sun exposure. Compared with those who had never smoked, the rate of subsequent squamous cell skin cancer was higher among current smokers (rate ratio, 2.01; 95% confidence interval, 1.21 to 3.34) and former smokers (rate ratio, 1.62; 95% confidence interval, 1.07 to 2.47) and increased with both duration and amount smoked. There was no clear relationship between smoking and basal cell skin cancer; the rate appeared lower among heavy smokers but was unrelated to duration of smoking. CONCLUSIONS--Persons with a prior nonmelanoma skin cancer had a substantial 5-year risk of developing another tumor of the same histologic type. Number of previous skin cancers, solar damage, and skin sensitivity to sun exposure were particularly related to this risk. The increased risk of squamous cell skin cancer associated with cigarette smoking merits further study.
===================================================================
23.) Topical photoprotection for hereditary polymorphic light eruption of American Indians.
===================================================================
SO - J Am Acad Dermatol 1991 May;24(5 Pt 1):744-6
AU - Fusaro RM; Johnson JA
PT - JOURNAL ARTICLE
AB - We evaluated the photoprotective efficacy of a broad-spectrum sunscreen containing a UVA screen (butyl methoxydibenzoylmethane) and a UVB screen (octyl dimethyl p-aminobenzoic acid) in patients with hereditary polymorphic light eruption. At least 18 of the 30 patients who enrolled in the study were sensitive to sunlight through window glass, an indication of UVA sensitivity. Of the 21 patients who completed the clinical trial, the physician's evaluation was that 18 (86%) obtained good to excellent results. Self-evaluation by the patients revealed that 16 (76%) noted more photoprotection than from previous treatments.
===================================================================
24.) Efficiency of opaque photoprotective agents in the visible light range [see comments]
===================================================================
CM - Comment in: Arch Dermatol 1992 Mar; 128(3):409
SO - Arch Dermatol 1991 Mar;127(3):351-5
AU - Kaye ET; Levin JA; Blank IH; Arndt KA; Anderson RR
PT - JOURNAL ARTICLE
AB - "Opaque" physical sunscreens are important for photoprotection of individuals with visible light and UV-A photosensitivity such as those with porphyria, drug photoallergy, and polymorphous light eruption. Diffuse spectral transmittance of various thicknesses of opaque sunscreen formulations were measured from 350- to 800-nm range using a spectrophotometer equipped with an integrating sphere. Transmission through 20% zinc oxide paste was high and decreased minimally despite large increases in the sunscreen layer thickness. Adding a visible light absorber such as iron oxide to scattering sunscreens, however, substantially lowered transmittance below that predicted by the product of the transmittances for each component alone. Opaque sunscreens protected against hematoporphyrin derivative photosensitization of albino guinea pig skin; these results were quantitatively consistent with the in vitro findings. Poor photoprotection against visible light is obtained with white paste sunscreens, even if thick layers are applied. The addition of pigments to such sunscreens, however, greatly enhances photoprotection and cosmetic acceptability.
===================================================================
25.) Photoprotective effect of topically applied superoxide dismutase on sunburn reaction in comparison with sunscreen.
===================================================================
SO - J Dermatol 1990 Oct;17(10):595-8
AU - Hamanaka H; Miyachi Y; Imamura S
PT - JOURNAL ARTICLE
AB - Photoprotective effect of topically applied superoxide dismutase (SOD) to guinea pig skin was compared with a commercially available sunscreen agent after a single exposure to UVB. While cutaneous SOD activity was remarkably decrease in non-treated control animals, both topical SOD and sunscreen agent significantly reduced the decrease in skin SOD activity after UVB irradiation. However, only the sunscreen agent successfully reduced erythema reaction 24h after irradiation but topical SOD failed. These findings suggest that topical SOD protects skin from photo-oxidative damage without affecting erythema response, and thus, from a practical standpoint, sunscreen agents, when compared with topical antioxidants, seem better at present for daily photoprotection.
===================================================================
26.) Photoprotective effect of topical anti-inflammatory agents against ultraviolet radiation-induced chronic skin damage in the hairless mouse.
===================================================================
SO - Photodermatol Photoimmunol Photomed 1990 Aug;7(4):153-8
AU - Bissett DL; Chatterjee R; Hannon DP
PT - JOURNAL ARTICLE
AB - Albino hairless mice (Skh:HR-1) exposed chronically to suberythemal doses of ultraviolet (UV) radiation display visible and histological alterations in the skin. One alteration is an increase in dermal cellularity, including inflammatory cells. This suggested a role for inflammation in chronic photodamage. We evaluated the photoprotective effect of topical hydrocortisone, ibuprofen, and naproxen against photodamage. All 3 agents protected against UVB radiation-induced visible wrinkling, tumor formation, and histological alterations. Hydrocortisone and naproxen were also evaluated for protection against UVA radiation-induced visible skin sagging and histological alterations. Both were very effective. These data indicate that chronic topical application of anti-inflammatory agents provides broad solar UV spectrum photoprotection.
===================================================================
27.) Systemic photoprotective agents.
===================================================================
SO - Photodermatol 1987 Aug;4(4):187-95
AU - Black HS
PT - JOURNAL ARTICLE; REVIEW (67 references); REVIEW, TUTORIAL
AB - The concept of an effective, safe systemic photoprotectant circumvents many of the shortcomings associated with the use of topical agents as a modality preventive of actinic damage. On the other hand, difficulties resulting from systemic metabolism and toxicity complicate this approach. The problems are exemplified by the fact that some agents such as the antimalarials, psoralens, and carotenoids have been successfully employed in the treatment of specific photosensitive diseases but, aside from any potential toxicities, their ameliorative effects appear to be related to the particular pathomechanisms of the responding disease rather than general photoprotection. The complexity of systemic approaches is further demonstrated by the fact that agents possessing protective properties, e.g. butylated hydroxytoluene and carotenoids, inhibit UV carcinogenesis, while others, e.g., 8-methoxypsoralen, potentiate this process. Nevertheless, from this ostensible disorder of responses, it seems apparent that those agents holding the greatest promise for future investigation are those capable of enhancing natural defense mechanisms, i.e., melanization and antiradical activity. Thus, while none of the agents reviewed here are deemed suitable as general photoprotectants, the fact that only a modest, measured protective effect can elicit a dramatic decrease in actinic damage (particularly with respect to cancer) upholds this concept as an important goal.
===================================================================
28.) A mode of action for butylated hydroxytoluene-mediated photoprotection.
===================================================================
SO - J Invest Dermatol 1986 Sep;87(3):343-7
AU - Koone MD; Black HS
PT - JOURNAL ARTICLE
AB - Dietarily administered butylated hydroxytoluene (BHT) has previously been shown to inhibit UV radiation induction of carcinogenesis, erythema, and ornithine decarboxylase (ODC) activity. Butylated hydroxytoluene feeding also resulted in significant increases in epidermal absorption and it was suggested that BHT's photoprotective properties might be attributable to a diminution of UV radiation dose reaching respective target sites. To explore this possibility, the contribution of stratum corneum to BHT's photoprotective action was examined. SKH-Hr-1 hairless mice were fed diets containing 0.5% (w/w) BHT for 2 weeks prior to experimentation. Control animals received the unsupplemented ration. Stratum corneum from both groups was isolated and spectral transmission recorded. Transmission, between 280-320 nm, was approximately 65% greater through stratum corneum obtained from control animals compared with that of BHT-treated animals. Further evidence of the biologic significance of this BHT effect upon stratum corneum absorption was obtained when stratum corneum was first removed by tape-stripping, the animals irradiated with 0.45 J/cm2 of UVB, and epidermal ODC activity determined. BHT provided the usual inhibition of ODC activity induction in nonstripped animals, but ODC activity induction in BHT-treated, tape-stripped animals was restored to levels that did not significantly differ from controls. The protective effect exhibited by the stratum corneum could not be attributed to BHT-induced alteration of physical dimension, as neither the thickness of stratum corneum nor the number of stratum corneum layers, as determined from measurement of NaOH-distended frozen sections, differed from controls. Although the mechanism remains obscure, these data support the contention that systemically administered BHT results in diminished levels of UV radiation reaching potential epidermal target sites and delimits a large component of the photoprotective effect to the stratum corneum.
===================================================================
29.) In vivo evaluation of photoprotection against chronic ultraviolet-A irradiation by a new sunscreen Mexoryl SX.
===================================================================
SO - Photochem Photobiol 1992 Apr;55(4):549-60
AU - Fourtanier A; Labat-Robert J; Kern P; Berrebi C; Gracia AM; Boyer B
PT - JOURNAL ARTICLE
AB - In a previous study on the hairless mouse it was shown that sub-erythemal doses of pure UV-A enhanced the numerous changes normally observed during chronological aging. A new sunscreen (a bis-benzylidene campho sulfonic acid derivative) has been synthesized in our research laboratory (lambda max: 345 nm, epsilon: 47,000). Its photoprotective properties against UV-A induced damages were assessed in our mouse model. Three month old albino hairless mice were exposed for 1 y to suberythemal doses (35 J/cm2) of UV-A obtained from a xenon source filtered through a WG 345 filter. One group of animals was exposed untreated, the other received a formulation containing 5% of the sunscreen prior to irradiation. At the end of the study the cutaneous properties of protected mice were compared to those of unprotected animals and to 3 and 15 month old unirradiated controls. We found that the visible changes induced by UV-A irradiation were mainly sagging and wrinkling. Histological and electron microscopic alterations consisted of hyperkeratosis, increased density of elastic fibers with alteration of fiber orientation and increased glycosaminoglycan deposits. Biochemical changes consisted of decreases in total collagen and collagen hydroxylation and increases in both collagen III/I + III ratio and fibronectin biosynthesis. All these changes were reduced or abolished by the sunscreen.
===================================================================
30.) Systemic photoprotection.
===================================================================
SO - Dermatol Clin 1986 Apr;4(2):335-9
AU - Mathews-Roth MM
PT - JOURNAL ARTICLE
AB - At present, three classes of compounds are used as systemic photoprotective agents, but only for specific indications, not for general use in healthy individuals. Beta-carotene prevents or lessens photosensitivity in most patients with erythropoietic protoporphyria and in some patients with other photosensitivity diseases. The antimalarial drugs can clear up skin lesions in patients with polymorphous light eruption and solar urticaria who cannot obtain relief with topical sunscreens and in some patients with porphyria cutanea tarda. Oral psoralens and controlled exposure to sunlight or artificial sources of UVA radiation can increase tolerance to sunlight in fair-skinned individuals and in certain patients with vitiligo or polymorphous light eruption.
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31.) Evaluation of the photoprotective effect of oral vitamin E supplementation.
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SO - Arch Dermatol 1994 Oct;130(10):1257-61
AU - Werninghaus K; Meydani M; Bhawan J; Margolis R; Blumberg JB; Gilchrest BA
PT - CLINICAL TRIAL; JOURNAL ARTICLE; RANDOMIZED CONTROLLED TRIAL
AB - BACKGROUND AND DESIGN: Solar-induced cutaneous damage is mediated partly via oxidative pathways. Some evidence exists for a photoprotective role of antioxidants. In a double-blind, placebo-controlled study, we examined the effect of a long-term, orally administered antioxidant against UV-induced epidermal damage. Healthy human subjects supplemented their usual diet daily with either 400 IU of oral vitamin E (alpha-tocopherol acetate) or placebo over a 6-month period. Minimal erythema dose and histologic response to threefold minimal erythema dose exposure were determined at baseline, 1 month, and 6 months. RESULTS: The minimal erythema dose did not vary substantially at the three time points within each treatment group or in the vitamin E-supplemented group vs the placebo group. The number of sunburn cells produced by a threefold minimal erythema dose exposure was also not significantly different between the two groups. Of note, however, vitamin E levels in plasma increased only modestly and in skin biopsy specimens were unchanged following 1 month and 6 months of supplementation. CONCLUSIONS: No clinical or histologic difference in the response to UVB could be detected between the placebo and vitamin E-supplemented groups. In this small study, daily ingestion of 400 IU of oral alpha-tocopherol daily does not provide meaningful photoprotection.
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32.) Evidence for the photoprotective effects of vitamin E.
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SO - Photochem Photobiol 1993 Aug;58(2):304-12
AU - Fryer MJ
PT - JOURNAL ARTICLE; REVIEW (110 references); REVIEW, ACADEMIC
AB - The antioxidant vitamin E (alpha-tocopherol) may protect both animal and plant cell membranes from light-induced damage. The various biochemical and biophysical modes of protection are considered. An examination is made of the evidence that vitamin E plays an important prophylactic role against a number of serious light-induced diseases and conditions of the eye (cataractogenesis and retinal photodeterioration) and skin (erythrocyte photohemolysis, photoerythema, photoaging and photocarcinogenesis) that are mediated by photooxidative damage to cell membranes.
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33.) Photochemistry and photobiology of urocanic acid.
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SO - Photodermatol 1985 Jun;2(3):158-65
AU - Morrison H
PT - JOURNAL ARTICLE; REVIEW (60 references)
AB - E-Urocanic acid is a metabolite of histidine which accumulates in the skin and is excreted in sweat. It has been of interest to photobiologists and photodermatologists because of its intense absorption band at approximately 270 nm, a feature suggestive of a role as a natural photoprotecting agent for DNA. Early work concentrated on the E----Z isomerization resulting from UV excitation. Recent studies have revealed additional, potentially significant, photobiological properties, i.e. photochemical binding to DNA and an apparent involvement of the Z isomer in the phenomenon of photoimmunosuppression.
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34.) Determination of UVA protection factors by means of immediate pigment darkening in normal skin.
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SO - J Am Acad Dermatol 1991 Aug;25(2 Pt 1):262-6
AU - Kaidbey KH; Barnes A
PT - JOURNAL ARTICLE
AB - A method is described for screening potentially useful photoprotective agents against UVA radiation by the use of immediate pigment darkening as an end point. Threshold doses of immediate pigment darkening showed a log normal distribution and the response was found to obey dose-reciprocity at irradiance levels below 50 mW/cm2. With this procedure, several marketed sunscreens containing benzophenone-3 as the only UVA absorber were found to have poor UVA protection factors, whereas those containing combinations of benzophenone-3 and butyl methoxydibenzoyl methane or melanin were more effective. There was no correlation between the sun protection factor cited on the label and the calculated immediate pigment darkening-protection factor.
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35.) Broad-spectrum photoprotection: the roles of tinted auto windows, sunscreens and browning agents in the diagnosis and treatment of photosensitivity.
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SO - Dermatology 1992;185(4):237-41
AU - Johnson JA; Fusaro RM
PT - JOURNAL ARTICLE; REVIEW (14 references); REVIEW, TUTORIAL
AB - Since window glass absorbs sunlight below 320 nm, it provides a means of assessing sensitivity to longer wavelengths, i.e. UVA and visible radiation. Positive responses to the query of whether symptoms develop in the auto with the windows up must now be interpreted with regard to the possible presence of tinted plastic film on side and rear windows. These films block nearly all UVA radiation, as does the plastic interleaf of windshields. Thus, occupants of an auto equipped with plastic film receive photoprotection from UVB radiation and well into the UVA region. We define three classes of topical sunscreens: (1) conventional UVB screens, (2) broad-spectrum preparations containing a UVB screen and a UVA absorber and (3) browning agents such as dihydroxyacetone (DHA) that produce a skin coloration that absorbs in the low end of the visible region, with overlap into long-wavelength UVA. By considering responses of photosensitive persons in autos with tinted or untinted windows, coupled with efficacy of appropriate sunscreens, we produced an algorithm defining three photosensitivity subsets. Persons sensitive to long-wavelength UVA and/or visible radiation will benefit from tinted auto windows. In particular, patients with lupus erythematosus (LE) have actively promoted legislation allowing tinted windows. Support for their position is documented by recent reports of induction of lesions in LE patients by exposure to UVA and visible radiation. The brown color produced by DHA is a useful adjunct to the screening action of broad-spectrum sunscreens. Development of a durable color overnight allows application of the DHA preparation in the evening, thus eliminating possible interference with sunscreen use during the day.
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36.) Protective role of butylated hydroxytoluene and certain carotenoids in photocarcinogenesis.
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SO - Photochem Photobiol 1991 May;53(5):707-16
AU - Black HS; Mathews-Roth MM
PT - JOURNAL ARTICLE; REVIEW (71 references); REVIEW, TUTORIAL
AB - Butylated hydroxytoluene (BHT) and certain carotenoid pigments have been found to inhibit photocarcinogenesis in animal models. In addition, BHT protects against UV-B-induced erythema and UV-B induction of ornithine decarboxylase. Studies on the photoprotective mechanism(s) of BHT suggested that changes in the physico-chemical properties of the keratin of the stratum corneum layer of skin occurred, leading to increases in UV absorption of that tissue. These changes might be exerted via the anti-radical action of BHT that retards oxidation and prevents cross-linking of the keratin chains, resulting in a diminution of UV-B radiation reaching potential target sites. The carotenoids beta-carotene, canthaxanthin and phytoene also inhibit UV-B carcinogenesis. beta-Carotene and canthaxanthin are excellent quenchers of singlet oxygen, and all three pigments can quench free radicals. beta-Carotene and canthaxanthin have been shown to quench singlet oxygen/free radical reactions in the skin of porphyric mice, and these two pigments as well as phytoene have been found to quench excited species formed on irradiation of mouse skin by UV-B.
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37.) Persistent light reaction. Successful treatment with cyclosporin A.
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SO - Acta Derm Venereol 1988;68(2):176-8
AU - Duschet P; Schwarz T; Oppolzer G; Gschnait F
PT - JOURNAL ARTICLE
AB - A 53-year-old male patient who had suffered for several years from severe persistent light reaction possibly due to tribromsalan photosensitivity was treated with cyclosporin A after long-term low-dose administration of corticosteroids which had to be discontinued. PUVA therapy was impracticable due to the extraordinarily high UVA sensitivity. When cyclosporin A blood concentrations between 100 and 200 ng/ml were reached, the patient was nearly free from symptoms; the excellent clinical response was also documented by phototesting performed prior to and during therapy. Cyclosporin A may be a valuable therapeutic alternative to systemic corticosteroids for severe cases of persistent light reaction which cannot be controlled by photoprotective measures.
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38.) Comparison of methods for assessing photoprotection against ultraviolet A in ===================================================================
vivo.
SO - J Am Acad Dermatol 1987 Feb;16(2 Pt 1):346-53
AU - Kaidbey K; Gange RW
PT - JOURNAL ARTICLE
AB - Photoprotection against ultraviolet A (UVA) by three sunscreens was evaluated in humans, with erythema and pigmentation used as end points in normal skin and in skin sensitized with 8-methoxypsoralen and anthracene. The test sunscreens were Parsol 1789 (2%), Eusolex 8020 (2%), and oxybenzone (3%). UVA was obtained from two filtered xenon-arc sources. UVA protection factors were found to be significantly higher in sensitized skin compared with normal skin. Both Parsol and Eusolex provided better and comparable photoprotection (approximately 3.0) than oxybenzone (approximately 2.0) in sensitized skin, regardless of whether 8-methoxypsoralen or anthracene was used. In normal unsensitized skin, Parsol 1789 and Eusolex 8020 were also comparable and provided slightly better photoprotection (approximately 1.8) than oxybenzone (approximately 1.4) when pigmentation was used as an end point. The three sunscreens, however, were similar in providing photoprotection against UVA-induced erythema. Protection factors obtained in artificially sensitized skin are probably not relevant to normal skin. It is concluded that pigmentation, either immediate or delayed, is a reproducible and useful end point for the routine assessment of photoprotection of normal skin against UVA.
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39.) Canthaxanthin.
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SO - Int J Dermatol 1985 Oct;24(8):528-32
AU - Gupta AK; Haberman HF; Pawlowski D; Shulman G; Menon IA
PT - JOURNAL ARTICLE
AB - Canthaxanthin is used as a food-coloring agent, a photoprotective agent in certain photodermatoses, a tan-simulating agent, and a pigment to darken vitiliginous skin. This article reviews the current literature on canthaxanthin and reports the evaluation of oral canthaxanthin as an artificial pigment for the management of vitiligo. Fifty-six patients were studied, using serum canthaxanthin levels, pre- and post-treatment photographs with standard conditions, physician assessment, and patient questionnaires evaluating treatment results. Canthaxanthin was rated "very satisfactory" by 10%, "satisfactory" by 35%, and "unsatisfactory" by 54% of patients. In light-skinned individuals, self-reports were "very satisfactory" in 27%, "satisfactory" in 45%, and "unsatisfactory" in 27%. In dark-skinned individuals, the treatment was less effective. Women were happier with the results than men. Major side effects were red stools and orange palms and soles. Canthaxanthin can be taken orally, is easy to use, and can be a cosmetically acceptable therapy in selected cases of vitiligo.
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40.) Disposition and metabolism of topically administered alpha-tocopherol acetate: a common ingredient of commercially available sunscreens and cosmetics.
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Author
Alberts DS; Goldman R; Xu MJ; Dorr RT; Quinn J; Welch K; Guillen-Rodriguez J; Aickin M; Peng YM; Loescher L; Gensler H
Address
Arizona Cancer Center, College of Medicine, University of Arizona, Tucson 85724, USA.
Source
Nutr Cancer, 26(2):193-201 1996
Abstract
Skin cancers are a serious health problem in the United States. One common method of skin cancer primary prevention is use of sunscreens. Research has been conducted to ascertain the role of active ingredients of sunscreen products in photoprotection and possible carcinogenesis. In contrast, little is known about the "other ingredients", listed or unlisted, on sunscreen product labels. One such ingredient is vitamin E. usually in the form of alpha-tocopherol acetate. Results of recent studies of skin carcinogenesis in an ultraviolet (UV) B mouse carcinogenesis model suggest that topically applied alpha-tocopherol acetate does not prevent and, under some conditions, enhances skin cancer development and growth, whereas the free unesterified from of alpha-tocopherol significantly reduces experimental UVB carcinogenesis. We have performed a Phase II cancer prevention study to evaluate whether topically applied alpha-tocopherol acetate is absorbed in human skin and metabolizes to the free or other forms. In this double-blind study, 19 men and women > 30 years of age who had at least three actinic keratoses on their forearms were randomly assigned to apply alpha-tocopherol acetate (125 mg/g) or difluoromethylornithine cream to their arms twice daily for three months. Blood samples and photographs and punch biopsies of actinic keratoses were obtained before and at the end of the study (Month 4). Plasma and skin concentrations of free alpha-tocopherol, alpha-tocopherol acetate, and gamma-tocopherol were analyzed by high-performance liquid chromatography at Month 4. The results of this report focus only on data obtained from the 11 participants randomized to the alpha-tocopherol acetate arm of the study. Topically applied alpha-tocopherol acetate was substantially absorbed in skin, with no evidence of conversion within skin to its unesterified form (i.e., free alpha-tocopherol). There was no evidence of systemic availability or biotransformation of topically applied alpha-tocopherol acetate. In summary, we have determined that alpha-tocopherol acetate is not metabolized to the free form of alpha-tocopherol in plasma or skin.
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41.) Synergistic topical photoprotection by a combination of the iron chelator 2-furildioxime and sunscreen.
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Author
Bissett DL; McBride JF
Address
Miami Valley Laboratories, Procter & Gamble Company, Cincinnati, OH 45253-8707, USA.
Source
J Am Acad Dermatol, 35(4):546-9 1996 Oct
Abstract
BACKGROUND: Iron is a factor in skin photodamage, apparently by way of its participation in oxygen radical production. Certain topical iron chelators are photoprotective. OBJECTIVE: Our purpose was to determine the level of topical photoprotection provided by the iron chelator 2-furildioxime (FDO) in combination with sunscreen in short- and long-term photoprotection models. METHODS: Guinea pigs were treated topically with FDO, sunscreen, and a combination of the two and were then exposed to varying doses of UV radiation to determine the sun protection factor (SPF). Hairless mice were treated topically with FDO, sunscreen, and a combination of the two and then subjected to long-term exposure to a suberythemal dose of UV radiation. The mice were evaluated for skin wrinkling and skin tumors. RESULTS: In guinea pigs, topical FDO combined with sunscreen provided more than additive protection; 5% FDO alone provides approximately SPF 4, whereas 5% FDO combined with an SPF 4 sunscreen product yielded an SPF of more than 30. In hairless mice exposed long term to UV radiation, 5% FDO and sunscreen delayed tumor onset by a mean of 8 and 12 weeks, respectively. The combination of FDO and sunscreen delayed tumor onset by a mean of 58 weeks. A similar more than additive level of protection was observed for 1skin wrinkling. CONCLUSION: Topical FDO combined with sunscreen is a potent photoprotection system against both short- and long-term UV radiation exposure.
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42.) Topical or oral administration with an extract of Polypodium leucotomos prevents acute sunburn and psoralen-induced phototoxic reactions as well as depletion of Langerhans cells in human skin.
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Author
Gonz´alez S; Pathak MA; Cuevas J; Villarrubia VG; Fitzpatrick TB
Address
Department of Dermatology, Massachusetts General Hospital, Boston 02114, USA.
Source
Photodermatol Photoimmunol Photomed, 13(1-2):50-60 1997 Feb-Apr
Abstract
Sunburn, immune suppression, photoaging, and skin cancers result from uncontrolled overexposure of human skin to solar ultraviolet radiation (UVR). Preventive measures, including photoprotection, are helpful and can be achieved by topical sunscreening agents. Polypodium leucotomos (PL) has been used for the treatment of inflammatory diseases and has shown some in vitro and in vivo inmunomodulating properties. Its beneficial photoprotective effects in the treatment of vitiligo and its antioxidant properties encouraged us to evaluate in vivo the potentially useful photoprotective property of natural extract of PL after topical application or oral ingestion. Twenty-one healthy volunteers [either untreated or treated with oral psoralens (8-MOP or 5-MOP)] were enrolled in this study and exposed to solar radiation for evaluation of the following clinical parameters: immediate pigment darkening (IPD), minimal erythema dose (MED), minimal melanogenic dose (MMD), and minimal phototoxic dose (MPD) before and after topical or oral administration of PL. Immunohistochemical assessment of CD1a-expressing epidermal cells were also performed. PL was found to be photoprotective after topical application as well as oral administration. PL increased UV dose required for IPD (P < 0.01), MED (P < 0.001) and MPD (P < 0.001). After oral administration of PL, MED increased 2.8 +/- 0.59 times and MPD increased 2.75 +/- 0.5 and 6.8 +/- 1.3 times depending upon the type of psoralen used. Immunohistochemical study revealed photoprotection of Langherhans cells by oral as well as topical PL. The observed photoprotective activities of oral or topical PL reveal a new avenue in examining the potentially useful field of systemic photoprotection and suggests that PL can be used as adjunct treatment and can make photochemotherapy and phototherapy possibly safe and effective when the control of cutaneous phototoxicity to PUVA or UVB is a limiting factor in such phototherapies.
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43.) Effectiveness of antioxidants (vitamin C and E) with and without sunscreens as topical photoprotectants.
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Author
Darr D; Dunston S; Faust H; Pinnell S
Address
North Carolina Biotechnology Center, Raleigh, N.C., USA.
Source
Acta Derm Venereol, 76(4):264-8 1996 Jul
Abstract
Considerable interest has been recently generated concerning the use of natural compounds, anti-oxidants in particular, in photoprotection. Two of the best known anti-oxidants are vitamins C and E, both of which have been shown to be somewhat effective in different models of photodamage. Very little has been reported, however, on the effectiveness of a combination of the two (known to be biologically the more relevant situation); nor have there been detailed studies on the ability of these antioxidants to augment commercial sunscreen protection against UV damage. We report that (in swine skin) vitamin C is capable of additive protection against acute UVB damage (sunburn cell formation) when combined with a UVB sunscreen. A combination of both vitamins E and C provided very good protection from a UVB insult, the bulk of the protection attributable to vitamin E. However, vitamin C is significantly better than vitamin E at protecting against a UVA-mediated phototoxic insult in this animal model, while the combination is only slightly more effective than vitamin C alone. When vitamin C or a combination of vitamin C and E is formulated with a commercial UVA sunscreen (oxybenzone), an apparently greater than additive protection is noted against the phototoxic damage. These results confirm the utility of anti-oxidants as photoprotectants but suggest the importance of combining the compounds with known sunscreens to maximize photoprotection.
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44.) A review of sunscreen safety and efficacy.
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Author
Gasparro FP; Mitchnick M; Nash JF
Address
Department of Dermatology & Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA. [email protected]
Source
Photochem Photobiol, 68(3):243-56 1998 Sep
Abstract
The use of sunscreen products has been advocated by many health care practitioners as a means to reduce skin damage produced by ultraviolet radiation (UVR) from sunlight. There is a need to better understand the efficacy and safety of sunscreen products given this ongoing campaign encouraging their use. The approach used to establish sunscreen efficacy, sun protection factor (SPF), is a useful assessment of primarily UVB (290-320 nm) filters. The SPF test, however, does not adequately assess the complete photoprotective profile of sunscreens specifically against long wavelength UVAI (340-400 nm). Moreover, to date, there is no singular, agreed upon method for evaluating UVA efficacy despite the immediate and seemingly urgent consumer need to develop sunscreen products that provide broad-spectrum UVB and UVA photoprotection. With regard to the safety of UVB and UVA filters, the current list of commonly used organic and inorganic sunscreens has favorable toxicological profiles based on acute, subchronic and chronic animal or human studies. Further, in most studies, sunscreens have been shown to prevent the damaging effects of UVR exposure. Thus, based on this review of currently available data, it is concluded that sunscreen ingredients or products do not pose a human health concern. Further, the regular use of appropriate broad-spectrum sunscreen products could have a significant and favorable impact on public health as part of an overall strategy to reduce UVR exposure.
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45.) Inhibition of UVB induced DNA photodamage in mouse epidermis by topically applied alpha-tocopherol.
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Author
McVean M; Liebler DC
Address
Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson 85721-0207, USA.
Source
Carcinogenesis, 18(8):1617-22 1997 Aug
Abstract
Ultraviolet B (UVB, 290-320 nm) exposure results in a variety of cellular insults including induction of cyclobutane pyrimidine dimers in DNA. Accumulation of these lesions can lead to mutations in critical genes and contribute to the development of nonmelanoma skin cancer. Topically applied alpha-tocopherol (vitamin E) has previously been shown to prevent the induction of skin tumors in UVB irradiated female C3H/HeNTac mice. We hypothesized that alpha-tocopherol, which absorbs strongly in the UVB, may act as a sunscreen to prevent photodamage. To explore possible mechanisms of photoprotection, we topically applied alpha-tocopherol dispersed in a neutral cream vehicle to the dorsal epidermis of female C3H/HeNTac mice and exposed them to 2.5 J/m2/s of UVB for 60 min. Immediately after exposure, we analyzed thymine dimer levels in DNA by capillary gas chromatography with electron capture detection. Epidermal DNA from mice receiving this UVB dose contained 247 +/- 42 pmol thymine dimers/micromol thymine. Topical application of alpha-tocopherol inhibited dimer formation in a dose-dependent manner. A 1% alpha-tocopherol dispersion inhibited the formation of thymine dimers to 43% of levels in vehicle controls. Several vitamin E compounds, including alpha-tocopherol acetate, alpha-tocopherol methyl ether, gamma-tocopherol, and delta-tocopherol also inhibited thymine dimer formation, but were five- to ten-fold less potent than alpha-tocopherol. A variety of commercially available sunscreens were also less potent than alpha-tocopherol in their ability to reduce dimer formation. These results suggest that DNA photoprotection is an important mechanism by which topically applied alpha-tocopherol can inhibit UVB induced skin cancer. Alpha-Tocopherol acetate, the most common form of vitamin E in commercial skin care products, conferred less protection, perhaps due to its lower absorptivity in the UVB. Our results further underscore the importance of determining which forms of vitamin E can inhibit specific lesions involved in photocarcinogenesis.
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46.) Photoprotection: sunscreens and the immunomodulatory effects of UV irradiation.
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Author
Finlay-Jones JJ; Hart PH
Address
Department of Microbiology and Infectious Diseases, School of Medicine, Flinders University of South Australia, Adelaide, Australia. [email protected]
Source
Mutat Res, 422(1):155-9 1998 Nov 9
Abstract
UV-B irradiation (UVR) of the host, in both humans and animal models, induces dose-related acute and chronic changes in skin which include erythema and photoageing, and induction of cancer. It can also induce modulation of immune responses of the host to antigens presented following irradiation. Commercially-available, broad-spectrum, high SPF (15, 15 + ) sunscreens protect against most effects of UV irradiation. An exception is the effects of UVR on immune responsiveness, with varying degrees of protection having been reported. We examined a system of UV-induced systemic suppression of contact hypersensitivity (CHS) responses in BALB/c mice. A range of commercially-available, broad spectrum, high SPF (15 + ) sunscreens demonstrated at best partial protection against systemic immunosuppression, yet were able to protect against two hallmarks of acute UVR-induced damage: skin oedema and keratinocyte proliferation. Two major models have been identified for the induction of immunosuppression following UVR, one identifying trans-urocanic acid (trans-UCA; deaminated histidine, located in the stratum corneum) as the critical photoreceptor, the other featuring DNA. UVR of trans-UCA produces cis-UCA, which itself is immunomodulatory. There was some abrogation of trans to cis isomerisation of urocanic acid in UV-irradiated, sunscreen-protected mice. However, the majority of the immunomodulation seen in these mice was abrogated by pretreatment with a monoclonal antibody to cis-urocanic acid. It is possible to induce formation of cis-urocanic acid in BALB/c skin in the absence of immunosuppression, using lower doses of UV radiation, indicating that formation of cis-urocanic acid in the stratum corneum is not necessarily sufficient to induce immunosuppression in the UV-irradiated host. The mechanisms of induction of the immunomodulated state in the UV-irradiated host are potentially diverse and the subject of ongoing debate. Our studies maintain a role for cis-UCA, and form the basis for further studies on its involvement in immunomodulation by UVR in sunscreen-protected hosts.
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47.) Photoprotective and antiinflammatory effects of topical glycolic acid.
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Author
Perricone NV; DiNardo JC
Address
Department of Dermatology, Yale Medical School, New Haven, Connecticut, USA.
Source
Dermatol Surg, 22(5):435-7 1996 May
Abstract
BACKGROUND: Concerns about photosensitizing potential of alpha hydroxy acids have been expressed. A previous study, however, reported topical glycolic acid showing the opposite potential, that is, photoprotective. This study was designed to test the antiinflammatory and photoprotective capabilities of glycolic acid. OBJECTIVE: The effects of short-wave ultraviolet light (UVB) on skin treated with glycolic acid were evaluated in two different studies at two different locations. METHODS: In the first study the antiinflammatory potential of topical glycolic acid was tested on erythematous templates on the backs of human volunteers. Erythema was induced by exposure to three times the minimum erythema dose (MED) of UVB. Glycolic acid cream in an oil-in-water vehicle at 12% partially neutralized with ammonium hydroxide to a pH of 4.2 was applied to the template beginning 4 hours postirradiation four times a day. A second template on the same subject was used as a vehicle control. After 48 hours a marked reduction of erythema was noted when compared with the vehicle control site. In the second study, four test sites were exposed to UVB light in the following manner. Site 1 was a nontreated control site and was used to establish the MED for the subjects being tested; site 2 was also exposed to a MED series but was treated 24 hours postirradiation for 7 days with two glycolic acid-based products (cleanser and oil-free moisture lotion, both containing 8.0% glycolic acid at a pH of 3.25); site 3 was treated first with the two glycolic acid-based formulas for 3 weeks prior to being exposed to UVB light; and site 4 was treated as outlined in site 3, with the inclusion that the site was chemically peeled for 6 minutes (with a 50% glycolic solution at a pH of 2.75) 15 minutes prior to UVB exposure. RESULTS: When UVB-burned skin was treated with glycolic acid daily for 7 days (site 2), a 16% reduction in irritation was observed compared to nontreated skin (site 1), implying that skin healed sooner when treated with glycolic acid. When a comparison of nontreated skin was made to skin treated with glycolic acid for 3 weeks prior to UVB exposure (site 1 vs site 3), a sun protection factor (SPF) of 2.4 was achieved. When a comparison of skin treated for 3 weeks was made to skin treated for 3 weeks and chemically peeled (site 3 vs site 4) the data implied that the chemical peel reduced the SPF value of skin treated with glycolic by approximately 50%, however, an SPF trend of 1.7 was still obtained when compared with untreated skin. CONCLUSIONS. The studies demonstrated that topical glycolic acid provides a photoprotective effect to pretreated skin yielding an SPF of approximately 2.4. In addition, when glycolic acid is applied to irradiated skin, it accelerates resolution of erythema. The data obtained from both studies support the hypothesis that glycolic acids acts as an antioxidant.
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48.) Sunscreens used at the beach do not protect against erythema: a new definition of SPF is proposed.
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Author
Wulf HC; Stender IM; Lock-Andersen J
Address
Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Denmark.
Source
Photodermatol Photoimmunol Photomed, 13(4):129-32 1997 Aug
Abstract
Since sunscreens are recommended by doctors and used all over the world to protect against sun induced erythema, it is important to evaluate if sunscreens are used as recommended and if the intended effect is achieved. We refer to the findings of several studies performed on people at risk of sun-burning at beaches in the vicinity of Copenhagen, Denmark. On a sunny day at the beach 65% of the sunbathers used one or more sunscreens. Of these, 46% used the sunscreen all over the body and a median sun protection factor (SPF) of 5-6 was used. The sunbathers used 0.5 mg/cm2 of sunscreen independent of skin type. Of the sunscreen users, 43% applied the sunscreen after arriving at the beach and 43% reapplied the sunscreen after swimming. The sun exposure time and the sun exposure dose were almost identical among sunscreen users and non-users. Self-assessed redness of the skin demonstrated that more sunscreen users than non-users reported to be red the day after sun exposure, 42 and 34%, respectively. Theoretical calculations support this findings and show a drastic reduction in the achieved photoprotection if a thinner layer than in the test situation is used. Sunscreens do not protect against erythema if not used as intended. Instead of changing people's habits, we suggest modifying the test method by adjusting the amount of sunscreen to that used in real life situations, 0.5 mg/cm2.
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49.) Normal vitamin D levels can be maintained despite rigorous photoprotection: six years' experience with xeroderma pigmentosum.
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Author
Sollitto RB; Kraemer KH; DiGiovanna JJ
Address
Dermatology Clinical Research Unit, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Source
J Am Acad Dermatol, 37(6):942-7 1997 Dec
Abstract
BACKGROUND: Although sun protection is advocated for skin cancer prevention, sunlight is also important in generation of vitamin D in the skin. There is concern that sun protection may result in an abnormally low level of vitamin D. OBJECTIVE: To assess the risk of vitamin D deficiency in a sunlight-deprived population, we studied eight ambulatory patients with xeroderma pigmentosum (XP) who practiced intensive sun protection during a chemoprevention study of oral isotretinoin. METHODS: We surveyed the patients to determine the extent of sun protection and vitamin D intake and measured the serum levels of two vitamin D metabolites (25-hydroxyvitamin D [25-OHD] and 1,25-dihydroxyvitamin D [1,25-(OH)2D]), calcium, and parathyroid hormone during 6 years. RESULTS: The patients all wore protective clothing and sunscreens when outdoors. Estimated mean vitamin D intake was normal. The mean values of serum 25-OHD were low normal, but 1,25-(OH)2D, calcium, ionized calcium and parathyroid hormone levels were normal. Lack of seasonal variation in serum 25-OHD indicated rigorous photoprotection. CONCLUSION: Despite rigorous sun protection normal vitamin D levels can be maintained in ambulatory patients with XP.
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50.) Decreased p53 expression in chronically sun-exposed human skin after topical photoprotection.
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Author
Berne B; Pont´en J; Pont´en F
Address
Department of Dermatology, University Hospital, Uppsala, Sweden.
Source
Photodermatol Photoimmunol Photomed, 14(5-6):148-53 1998 Oct-Dec
Abstract
UV-induced DNA damage appears to play an essential role in skin carcinogenesis. Following acute UV irradiation, there is an overexpression of normal p53 protein in epidermal keratinocytes, representing a physiological response to DNA damage. Sun protection through topical sunscreens or clothing is believed to reduce the hazardous effects of UV irradiation and subsequently the risk of skin cancer. We have examined the effect of an SPF 15 topical sunscreen and blue denim fabric (SPF 1700) in chronically sun-exposed human skin after sun exposure during a normal summer. Skin biopsies from sun-protected and sun-exposed skin were compared with respect to immunohistochemically detectable p53. This method provides a model for assessing the significance of different degrees of UV protection under physiological conditions. Our results show a significant reduction of p53-positive cells in sun-protected skin as compared with sun-exposed skin. The reduction of p53-positive keratinocytes differed between topical sunscreen (33% reduction) and blue denim fabric (66% reduction). Interindividual variations were large, possibly because of variations in sun exposure. These variations also suggest that mechanisms determining UV damage at the cellular level are complex. The role of residual p53-positive keratinocytes after 2 months of total sun-protection (i.e., SPF 1700) is discussed.
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51.) Trends in photoprotection in American fashion magazines, 1983-1993. will fashion make you look old and ugly?
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Author
George PM; Kuskowski M; Schmidt C
Address
University of Minnesota, Department of Dermatology, Minneapolis, USA.
Source
J Am Acad Dermatol, 34(3):424-8 1996 Mar
Abstract
BACKGROUND: During the past 50 years recreational sun exposure has greatly increased in the United States. OBJECTIVE: The purpose of this study was to examine the photoprotecion message of American fashion magazines and to identify recent trends. METHODS: We evaluated models for tan, skin exposure, and other sun-related criteria in six leading fashion magazines between 1983 and 1993. We also recorded the number of sunscreen advertisements and sun awareness articles. RESULTS: We evaluated 3031 models. Adult models had darker tans and greater skin exposure than adolescents and children. Men had darker tans than women. We noted trends toward lighter tans, more women wearing hats, more sunscreen advertisements, and sun awareness articles. Many sunscreen advertisements glorified tanning. Their models had darker tans and more skin exposure, and fewer wore a hat than did nonadvertisement models. CONCLUSION: The fashion industry and especially sunsreen manufacturers promote excessive sun exposure. Although we found encouraging trends, gains were modest, especially in men's magazines.
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52.) Sunscreens offer the same UVB protection factors for inflammation and immunosuppression in the mouse [see comments]
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Author
Walker SL; Young AR
Address
Department of Photobiology, St. John's Institute of Dermatology, United Medical and Dental Schools of Guy's and St Thomas's Hospital, University of London, U.K.
Source
J Invest Dermatol, 108(2):133-8 1997 Feb
Abstract
Many studies report that sunscreens effective against UVR-induced inflammation afford poor protection against immunosuppression. We have studied the relationship between photoprotection of inflammation and immunosuppression with monochromatic UVB (Philips TL01 tubes, lambda max = 311 nm) to remove possible confounding effects of differences in end point action spectra. Dose-response curves for edema and systemic suppression of contact hypersensitivity (CHS) in HRA.HRII-c/+/Skh mice showed that suppression of CHS was more sensitive to UVB irradiation by a factor of 2. The UVB dose-response curve for murine edema was similar to that for human erythema, with threshold doses of 773 mJ x cm(-2) and 632 mJ x cm(-2), respectively. The protection afforded by two UVB filters, octyl dimethyl para-aminobenzoic acid and 2-ethylhexyl-4'-methoxycinnamate, prepared in an identical vehicle, each with the same optical density at 311 nm, was tested in mice. We applied sunscreen to all exposed skin or to transpore tape above the irradiation cages, prior to exposure with 2.8 minimal edema doses. Topical or tape application of both sunscreens protected totally against edema but only partially against immunosuppression, with no significant difference in protection between the two application techniques (p > 0.4). A sunscreen protection factor of 4 in vivo was determined for 2-ethylhexyl-4'-methoxycinnamate for both edema and immunosuppression. Failure of the sunscreens to protect completely against immunosuppression was due to the ability of subedemal doses of UVB to induce substantial immunosuppression and not, as previously suggested, to any skin interaction.
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53.) Microfine zinc oxide (Z-cote) as a photostable UVA/UVB sunblock agent.
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Author
Mitchnick MA; Fairhurst D; Pinnell SR
Address
sunSmart Inc, Wainscott, New York, USA.
Source
J Am Acad Dermatol, 40(1):85-90 1999 Jan
Abstract
BACKGROUND: Microfine zinc oxide (Z-Cote) is used as a transparent broad-spectrum sunblock to attenuate UV radiation (UVR), including UVA I (340-400 nm). OBJECTIVE: Our purpose was to assess the suitability of microfine zinc oxide as a broad-spectrum photoprotective agent by examining those properties generally considered important in sunscreens: attenuation spectrum, sun protection factor (SPF) contribution, photostability, and photoreactivity. METHODS: Attenuation spectrum was assessed by means of standard spectrophotometric methods. SPF contribution was evaluated according to Food and Drug Administration standards. Photostability was measured in vitro by assessing SPF before and after various doses of UVR. Photoreactivity was evaluated by subjecting a microfine zinc oxide/organic sunscreen formulation to escalating doses of UVR and determining the percentage of organic sunscreen remaining. RESULTS: Microfine zinc oxide attenuates throughout the UVR spectrum, including UVA I. It is photostable and does not react with organic sunscreens under irradiation. CONCLUSION: Microfine zinc oxide is an effective and safe sunblock that provides broad-spectrum UV protection, including protection from long-wavelength UVA.
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54.) Potentials and limitations of the natural antioxidants RRR-alpha-tocopherol, L-ascorbic acid and beta-carotene in cutaneous photoprotection.
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Author
Fuchs J
Address
Department of Dermatology, School of Medicine, J.W. Goethe University, Frankfurt, Germany.
Source
Free Radic Biol Med, 25(7):848-73 1998 Nov 1
Abstract
Sun exposure has been linked to several types of skin damage including sun burn, photoimmunosuppression, photoaging and photocarcinogenesis. In view of the increasing awareness of the potentially detrimental long term side effects of chronic solar irradiation there is a general need for safe and effective photoprotectants. One likely hypothesis for the genesis of skin pathologies due to solar radiation is the increased formation of reactive oxidants and impairment of the cutaneous antioxidant system. Consequently, oral antioxidants that scavenge reactive oxidants and modulate the cellular redox status may be useful; systemic photoprotection overcomes some of the problems associated with the topical use of sunscreens. Preclinical studies amply illustrate the photoprotective properties of supplemented antioxidants, particularly RRR-alpha-tocopherol, L-ascorbate and beta-carotene. However, clinical evidence that these antioxidants prevent, retard or slow down solar skin damage is not yet convincing. The purpose of this review is to provide the reader with current information on cutaneous pathophysiology of photoxidative stress, to review the literature on antioxidant photoprotection and to discuss the caveats of the photo-oxidative stress hypothesis.
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55.) Photoprotective actions of natural and synthetic melanins.
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Chem Res Toxicol 1998 Dec;11(12):1434-40
Krol ES, Liebler DC
Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, P.O. Box 210207, Tucson, Arizona 85721, USA.
Melanins are thought to be important modulators of photochemistry in skin. Eumelanin, a black-brown pigment, is believed to protect against UV-induced photodamage, whereas pheomelanin, a red-yellow pigment, is believed to possess photosensitizing properties. To investigate the hypothesized dichotomy of melanins as both photoprotectants and photosensitizers, we examined the effects of melanins on UV-induced liposomal lipid peroxidation. Sepia melanin, a representative eumelanin, and both red hair pheomelanin and synthetic pheomelanin were employed in these studies. Both eumelanin and pheomelanin inhibited UVA/B- and UVA-induced liposomal lipid peroxidation in a concentration-dependent manner as measured by inhibition of conjugated diene formation. No change in protective properties of the melanins was observed in the presence of saturating levels of O2 during UVA irradiation. Pheomelanin irradiated with UVA/B or UVA induced superoxide-catalyzed reduction of nitroblue tetrazolium, whereas eumelanin did not. Melanins are known to bind various metals, and we examined the effect of iron on the photoproperties of melanins. Eumelanin complexed with Fe(III) did not inhibit UVA/B-induced lipid peroxidation, whereas pheomelanin complexed with Fe(III) stimulated UVA/B-induced lipid peroxidation. Thus, complexation with iron reversed the antioxidant effect of eumelanin and converted pheomelanin into a prooxidant. Analysis of lipid peroxidation products indicated that the oxidation was mediated by free radicals rather than by singlet oxygen. These data indicate that both eumelanin and pheomelanin exert antioxidant effects against UV-induced lipid peroxidation but that the prooxidant activities of pheomelanin result from pheomelanin-metal complexation.
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56.) Topical melatonin in combination with vitamins E and C protects skin from ultraviolet-induced erythema: a human study in vivo.
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Br J Dermatol 1998 Aug;139(2):332-9
Dreher F, Gabard B, Schwindt DA, Maibach HI
University of California, School of Medicine, Department of Dermatology, Box 0989, Surge 110, San Francisco, CA 94143, USA.
In this randomized, double-blind human study, the short-term photoprotective effects of different antioxidants and their combinations were evaluated in vivo. Vitamin C (ascorbic acid), vitamin E (alpha-tocopherol) and melatonin (N-acetyl-5-methoxytryptamine) were topically applied, alone or in combination, 30 min before ultraviolet-irradiation of the skin. The erythemal reaction was evaluated visually and non-invasively using different bioengineering methods (skin colour and skin blood flow). The results showed a modest protective effect of the vitamins when applied alone and a dose-dependent photoprotective effect of melatonin. Topical application of combinations of both vitamins, or of melatonin with vitamins, enhanced the photoprotective response. Better protection was obtained by using the combination of melatonin with both vitamins. The role of reactive oxygen species and oxygen-derived free radicals, as well as potential sunscreening properties of the employed antioxidants, are discussed in view of possible mechanisms to explain this elevated photoprotective effect.
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57.) Novel function of metallothionein in photoprotection: metallothionein-null mouse exhibits reduced tolerance against ultraviolet B injury in the skin.
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J Invest Dermatol 1998 Oct;111(4):582-5
Hanada K, Sawamura D, Tamai K, Baba T, Hashimoto I, Muramatsu T, Miura N, Naganuma A
Department of Dermatology, Hirosaki University School of Medicine, Japan.
We have shown previously that injection of cadmium chloride (Cd2+) depletes the number of ultraviolet B (UVB)-induced sunburn cells in the mouse skin in vivo, and that Cd2+ treatment enhances UVB resistance in cultured keratinocytes in vitro, indicating the photoprotective role of Cd2+-induced metallothioneins (MT) with antioxidant property against UVB injury; however, there has been no direct evidence for the role of MT in UV protection. To improve our understanding of MT in photoprotection, MT-null mouse deficient in its MT-1 and MT-2 genes was studied. Skin explants were preliminarily exposed to medium alone, Cd2+ and Cd2+ plus buthionine S,R-sulfoximine, an inhibitor of glutathione synthesis. We then compared the number of UVB-induced sunburn cells and apoptotic cells in the epidermis of MT-null mice with that of control mice using organ culture systems. The skin of MT-null mice developed a greater number of sunburn cells and apoptotic cells than did that of normal mice in all experimental conditions. These findings indicate that the skin of MT-null mouse is readily injured by UVB irradiation. MT-null mouse provided direct evidence of the photoprotective effect of cellular MT in the skin.
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58.) The photoprotective effect of 1,25-dihydroxyvitamin D3 on ultraviolet light B-induced damage in keratinocyte and its mechanism of action.
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J Dermatol Sci 1998 Sep;18(1):11-8
Lee J, Youn JI
Department of Dermatology, Inha University Medical School/Hospital, Incheon, South Korea.
We investigated the photoprotective effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) both in vivo and in vitro, revealing its relationship with glutathione, a well-known antioxidant. We also probed into the possible mechanism of photoprotection of 1,25(OH)2D3 through immunohistochemical study for metallothionein (MT). At the same time, endogenous antioxidant effect of 1,25(OH)2D3 was examined. Survival of cultured human keratinocytes was decreased when the cells were irradiated with ultraviolet light-B (UVB) at doses above 30 mJ/cm2. But in the presence of 1,25(OH)2D3 (12 nM), the decrease of survival of keratinocytes by UVB was diminished. The formation of sunburn cells by UVB irradiation in the skin of ICR mice was inhibited by topical application of 1,25(OH)2D3, regardless of prior glutathione depletion. Immunohistochemical staining revealed that 1,25(OH)2D3 induced the expression of MT, a potent radical scavenger, mainly in the basal layer of ICR mice skin. 1,25(OH)2D3 neither inhibited peroxidation of plasma lipids nor interacted with superoxide, nor removed hydrogen peroxide as an antioxidant. These findings suggest that 1,25(OH)2D3 has photoprotective effect not related with glutathione or its endogenous antioxidant property. Rather, it could be attributed to 1,25(OH)2D3-induced MT and its capacity to prevent radical-related damage in UVB irradiation.
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59.) Phototoxic lysis of erythrocytes from humans is reduced after oral intake of ascorbic acid and d-alpha-tocopherol.
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Photodermatol Photoimmunol Photomed 1997 Oct-Dec;13(5-6):173-7
Eberlein-Konig B, Placzek M, Przybilla B
Dermatologische Klinik und Poliklinik, Ludwig-Maximilians-Universitat Munchen, Germany.
Ultraviolet (UV) radiation causes hemolysis of human erythrocytes in the presence of photosensitizers. This can be used as an in vitro model for evaluating photosensitizing properties of substances. Antioxidants such as ascorbic acid (vitamin C) and d-alpha-tocopherol (vitamin E) have been found to be photoprotective in such test systems. We assessed the effect of combined systemic intake of both ascorbic acid and d-alpha-tocopherol by human volunteers on phototoxic in vitro lysis of their erythrocytes. In a double-blind placebo-controlled study, 10 subjects took daily 2 g ascorbic acid combined with 1000 IU d-alpha-tocopherol, and 10 took a placebo. Blood was taken before and after 7 days of treatment, erythrocytes were prepared and then incubated with 10(-3) mol/l fenofibrate, a photosensitizer acting in the UVA and UVB region. The suspensions were exposed to radiation rich in UVA (up to 40 J/cm2 UVA) or to radiation rich in UVB (up to 1.6 J/cm2). Photohemolysis of the samples was calculated as a percentage of complete hemolysis. At the end of the treatment phase, in the placebo group photohemolysis was not significantly reduced compared with the initial values at all irradiation doses except for 1.6 J/cm2 UVB (96% vs 79%; P < 0.01). In the group taking vitamins, photohemolysis was significantly reduced at nearly all UV doses, most impressively after moderate UVA irradiation (20 J/cm2 UVA: 86.5% vs 14.5%; P < 0.01). It is concluded that the results of the photohemolysis test are influenced by the antioxidative status of the cell donor and that ascorbic acid and d-alpha-tocopherol also may protect against phototoxic damage in vivo.
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60.) Furocoumarin-induced epidermal melanogenesis does not protect against skin photocarcinogenesis in hairless mice.
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Photochem Photobiol 1998 Jan;67(1):126-32
Kipp C, Lewis EJ, Young AR
Department of Photobiology, St. John's Institute of Dermatology, University of London, St. Thomas' Hospital, UK. [email protected]
Topical 6,4,4'-trimethylangelicin (TMA) plus UVA was used to induce intense epidermal pigmentation in inbred HRA.HRII-c/+/Skh hairless pigmented mice over a 13 day period. Subsequent UVB/UVA exposure was used to assess the photoprotective properties of this tan using skin tumors as an endpoint. Comparisons were always made with sibling albino mice. The TMA/UVA treatment was shown to be not carcinogenic when treated mice were compared with untreated control mice over 25 weeks. The tan faded despite daily exposure to UVB/UVA and did not afford any protection when TMA/UVA-treated mice with subsequent UVB/UVA were compared with pigmented mice treated with UVB/UVA only. In one group, the TMA-induced tan was maintained by application of TMA three times a week prior to UVB/UVA for the duration of the experiment. This treatment was associated with a significant increase in tumor risk in both pigmented and albino mice compared to groups treated with UVB/UVA alone. Although pigmented mice had a significant photoprotective advantage, it was shown to be outweighed by the carcinogenic risks of the TMA maintenance treatment when they were compared with mice that did not have this treatment. Nonpretanned pigmented mice developed mild pigmentation during UVB/UVA treatment that was shown to have no protective effect when those mice were compared with albinos. We conclude that induced epidermal tanning with or without furocoumarin enhancement is not an effective way to prevent skin cancer in the HRA.HRII-c/+/Skh mouse model.
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61.) Melanin.
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Int J Biochem Cell Biol 1997 Nov;29(11):1235-9
Riley PA
Department of Molecular Pathology, University College London Medical School, U.K.
Melanin is an irregular light-absorbing polymer containing indoles and other intermediate products derived from the oxidation of tyrosine. Melanin is widely dispersed in the animal and plant kingdoms. It is the major pigment present in the surface structures of vertebrates. The critical step in melanin biogenesis is the oxidation of tyrosine by the enzyme tyrosinase. In vertebrates this enzyme is active only in specialized organelles in retinal pigment epithelium and melanocytes. In mammals melanin is formed as intracellular granules. Melanin granules are transferred from melanocytes to epithelial cells and form the predominant pigment of hair and epidermis. Melanin has many biological functions. Reactive quinone intermediates in the melanin biosynthetic pathway exhibit antibiotic properties and the polymer is an important strengthening element of plant cell walls and insect cuticle. Light absorption by melanin has several biological functions, including photoreceptor shielding, thermoregulation, photoprotection, camouflage and display. Melanin is a powerful cation chelator and may act as a free radical sink. Melanin is used commercially as a component of photoprotective creams, although mainly for its free radical scavenging rather than its light absorption properties. The pigment is also a potential target for anti-melanoma therapy.
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62.) Photoprotective effect of calcipotriol upon skin photoreaction to UVA and UVB.
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Photodermatol Photoimmunol Photomed 1997 Jun;13(3):109-14
Youn JI, Park BS, Chung JH, Lee JH
Department of Dermatology, Seoul National University College of Medicine, Korea.
It has been shown that 1,25-dihydroxyvitamin D3 has a photoprotective effect against UVB injury in mouse skin and cultured rat keratinocytes by induction of metallothionein (MT). Calcipotriol is a synthetic analogue of 1,25-dihydroxyvitamin D3 with equipotent cell regulating properties, but with a lower risk of calcium-related side effects. The aim of the present study was to see whether calcipotriol has a photoprotective property both in vitro and in vivo. We examined the effect of calcipotriol on UV-induced damage of cultured human keratinocytes through a cell viability assay, and measurement of DNA synthesis by cultured keratinocytes, on UV-induced damage of mouse skin and on minimal erythema dose (MED). We found that calcipotriol was protective against UVB-induced reduction in DNA synthetic activity of cultured keratinocytes in relatively low doses (20 and 40 mJ/cm2) of UVB. With phototesting following application of calcipotriol, five subjects among 10 healthy volunteers and three among six psoriasis patients showed an increase in MED compared with the vehicle-treated site. These findings imply that calcipotriol may be photoprotective and that more extensive studies with various doses of UV irradiation and modes of calcipotriol delivery are required.
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63.) [Photosensitizing and photoprotective properties of extracts from groups of medicinal plants].
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Biofizika 1997 Jul-Aug;42(4):926-32
Bol'shakova IV, Lozovskaia EL, Sapezhinskii II
Investigation of photosensitization and photoprotection induced by plant extracts was carried out. A group of plants affected human central nervous system was studied in detail. Efficiency of plants as photoprotectors and photosensitizers was tested in the frame of the influence of their extracts on the yield of photochemiluminescence of Gly-Trp solutions. Photosensitization was studied under irradiation with light lambda > 280 nm and lambda > 320 nm, as well as with monochromatic light lambda=313, 365, 405 and 436 nm. All of the plants studied acted as photoprotectors in low concentration and as photosensitizers in high concentration. The efficiency of photoprotection and photosensitization was evaluated with regard to single dose of plant extracts and their concentration in human organism. The effect decreases in the following consequence of plants: Leonurus > Hypericum > Aralia > Schizandra > Echinopanax > Eleutherococcus > Valeriana > Panax ginseng. Photosensitization is due to the components of plant extracts which have strong absorbtion at the high wavelength range. The mechanism of photosensitization was suggested. Singlet oxygen generated by photoexcited compounds is the main species resulted in chemiluminescence. Superoxide radicals does not contribute significantly to the chemiluminescence formation.
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64.) Electron transfer and photoprotective properties of melanins in solution.
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Pigment Cell Res 1997 Aug;10(4):214-7
Menter JM, Willis I
Department of Medicine, Morehouse School of Medicine, Atlanta, GA 30310-1495, USA.
The polyquinoid nature of eumelanin(s) enables them to couple oxidation of electron donors with the reduction of electron acceptors. We have studied the ability of synthetic (Sigma) and "biological" (cuttlefish sepia) melanins to mediate electron transfer between hydroxybenzene donors (tyrosine, dopa, chemical depigmenters) and model acceptors (ferricyanide, tyrosinase). 1) Depending on the reductant, melanin either retards or accelerates ferricyanide reduction. Reaction kinetics are consistent with a mechanism involving non-interactive binding of both hydroxybenzene and ferricyanide to melanin prior to coupled electron transfer. 2) Melanins also act as an electron conduit in markedly accelerating the tyrosinase-catalyzed oxygenation of p-hydroxyanisole (MMEH). The active species appears to be a complex between melanin and MMEH. The magnitude of both effects depend on the type of melanin as well as its oxidation state. Sepia (eu)melanin appears to protect against UV-induced damage to acid-soluble collagen, as judged by irreversible loss of intrinsic collagen fluorescence. Photoprotection against this type of damage appears primarily to involve optical absorption/scattering by the pigment.
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65.) New actions of melatonin and their relevance to biometeorology.
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Int J Biometeorol 1997 Nov;41(2):47-57
Hardeland R
I. Zoologisches Institut, Universitat Gottingen, Germany.
Melatonin is not only produced by the pineal gland, retina and parietal but also by various other tissues and cells from vertebrates, invertebrates, fungi, plants, multicellular algae and by unicells. In plants, many invertebrates and unicells, its concentration often exceeds that found in vertebrate blood by several orders of magnitude. The action of melatonin is highly pleiotropic. It involves firstly, direct effects, via specific binding sites in various peripheral tissues and cells of vertebrates, including immunomodulation; secondly, systemic influences on the cytoskeleton and nitric oxide formation, mediated by calmodulin; and thirdly, antioxidative protection, perhaps also in the context of photoprotection in plants and unicells. In some dinoflagellates, melatonin conveys temperature signals. On the basis of these comparisons, melatonin appears to mediate and modulate influences from several major environmental factors, such as the photoperiod, radiation intensity and temperature.
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66.) Disposition and metabolism of topically administered alpha-tocopherol acetate: a common ingredient of commercially available sunscreens and cosmetics.
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Nutr Cancer 1996;26(2):193-201
Alberts DS, Goldman R, Xu MJ, Dorr RT, Quinn J, Welch K, Guillen-Rodriguez J, Aickin M, Peng YM, Loescher L, Gensler H
Arizona Cancer Center, College of Medicine, University of Arizona, Tucson 85724, USA.
Skin cancers are a serious health problem in the United States. One common method of skin cancer primary prevention is use of sunscreens. Research has been conducted to ascertain the role of active ingredients of sunscreen products in photoprotection and possible carcinogenesis. In contrast, little is known about the "other ingredients", listed or unlisted, on sunscreen product labels. One such ingredient is vitamin E. usually in the form of alpha-tocopherol acetate. Results of recent studies of skin carcinogenesis in an ultraviolet (UV) B mouse carcinogenesis model suggest that topically applied alpha-tocopherol acetate does not prevent and, under some conditions, enhances skin cancer development and growth, whereas the free unesterified from of alpha-tocopherol significantly reduces experimental UVB carcinogenesis. We have performed a Phase II cancer prevention study to evaluate whether topically applied alpha-tocopherol acetate is absorbed in human skin and metabolizes to the free or other forms. In this double-blind study, 19 men and women > 30 years of age who had at least three actinic keratoses on their forearms were randomly assigned to apply alpha-tocopherol acetate (125 mg/g) or difluoromethylornithine cream to their arms twice daily for three months. Blood samples and photographs and punch biopsies of actinic keratoses were obtained before and at the end of the study (Month 4). Plasma and skin concentrations of free alpha-tocopherol, alpha-tocopherol acetate, and gamma-tocopherol were analyzed by high-performance liquid chromatography at Month 4. The results of this report focus only on data obtained from the 11 participants randomized to the alpha-tocopherol acetate arm of the study. Topically applied alpha-tocopherol acetate was substantially absorbed in skin, with no evidence of conversion within skin to its unesterified form (i.e., free alpha-tocopherol). There was no evidence of systemic availability or biotransformation of topically applied alpha-tocopherol acetate. In summary, we have determined that alpha-tocopherol acetate is not metabolized to the free form of alpha-tocopherol in plasma or skin.
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67.) [Polymorphic light dermatitis. Photobiology and photoprotection].
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Med Cutan Ibero Lat Am 1976;4(1):45-52
Corrales Padilla H
It is possible in the majority of patients with polymorphic light eruption to produce lesions experimentally. Only the reproduction of the clinical reaction is significant for the diagnosis. Irradiation is carried out in the same test area two or three times with a dose of up to eight times the minimal erythema dose. Sunlight is the best agent for the evaluation of this protocutaneous disorder. A localised area of the skin can be exposed to midday sunshine about half an hour on three consecutive days. But sunlight has the disadvantage of having a variable ultraviolet emission at different times. It is necessary to differentiate lupus erythematosus and photocontact dermatitis, which may produce identical reactions. Other light sources are the hot quartz lamp, fluorescent tube "sun lamp", solar simulator and the monochromater. Patients with polymorphic light eruption are sensitive to light in the range 300 to 320 nm. but some of them are sensitive to savelengths shorter or longer than this range. The methods of protection against solar radiation which have been tried include: 1) Avoidance of sunlight; 2) Promotion of melanin hyperpgimentation and thickening of the stratum corneum-by controlled exposure to sunlight; 3) Application of a film of a chemical compound that will act as a physical screen and absorb, scatter or reflect damaging radiation; 4) Chemical modification of the stratum corneum by topically applied substances which can conjugate chemically or be absorbed onto the stratum corneum and filter the damaging rays. Many authors at present consider the use of alcoholic solutions of para-aminobenzoic acid (PABA) to be the most effective method of preventing reactions from exposure to sunlight. Pathak and Fitzpatrick showed that 5 % PABA in 70 % ethanol and 2,5 % Escalol 506 in 65 % ethanol is the most effective sunscreen against radiation of the sunburn spectrum. A dihydroxyacetone (DHA) and naphthaquinone (lawsone) sunscreen provides photoprotection for all types of photosensitivity throughout the whole UV spectrum even into the visible region. Systemic photoprotection: The administration of beta-carotene to patients with erythropoietic protoporphyria has resulted in amelioriation of their photosensitivity. Antimalarials are valuable therapeutic agents and are highly effective in controlling cutaneous lupus erythematosus, polymorphic light eruption and occasionally solar urticaria.
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DATA-MEDICOS/DERMAGIC-EXPRESS No (66) 21/07/99 DR. JOSE LAPENTA R.
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