The Experts below are selected from a list of 11643 Experts worldwide ranked by ideXlab platform
Hans Christian Wulf - One of the best experts on this subject based on the ideXlab platform.
-
application of Sunscreen theory and reality
Photodermatology Photoimmunology and Photomedicine, 2014Co-Authors: B. Petersen, Hans Christian WulfAbstract:Summary We present research on Sunscreen use with possible pitfalls and discuss theory vs. reality. A literature review in PubMed was conducted using the terms ‘Sunscreen application’, ‘Sunscreen use’ and ‘sun protection factor’. The sun protection factor (SPF) of Sunscreens are tested using a thickness of 2 mg/cm2, but investigations show that Sunscreen under natural conditions is applied insufficiently with amounts about 0.39 to 1.0 mg/cm2, which decreases the protection factor considerably. It has been shown that early reapplication or use of very high SPF (70–100) may partly compensate for the discrepancy between the amounts of Sunscreen applied during testing and in reality, and that Sunscreen application can be improved by education of consumers. Missing areas and ultraviolet radiation exposure before Sunscreen application are other pitfalls that reduce the protective effect of Sunscreens considerably. Current Sunscreen labelling overrates the protective effect of a given Sunscreen when the reality of Sunscreen use is taken into account. This may possibly mislead consumers to feel it is safe to extend sun exposure. Alternatively to educating people to use large amounts of Sunscreen, we suggest a simple teaching strategy: (1) Apply before sun exposure and (2) Reapply once within 1 h.
-
sun protection factor persistence during a day with physical activity and bathing
Photodermatology Photoimmunology and Photomedicine, 2008Co-Authors: Mette Bodekaer, Peter A. Philipsen, Annesofie Faurschou, Hans Christian WulfAbstract:Background/purpose: The persistence of Sunscreens during a day with physical activity and bathing is often debated. We wished to examine the durability of the protection achieved by one Sunscreen application. Methods: Seven areas were marked on the back of 24 volunteers. One area was phototested to determine UV sensitivity. Six areas were treated with either an organic or an inorganic Sunscreen (2 mg/cm2). The participants performed physical activities, were exposed to a hot environment and bathing during 8 h and were phototested with ultraviolet-B (UVB) radiation 30 min, 4 and 8 h after Sunscreen application. The minimal erythema dose (MED) was determined 24 h after irradiation. The sun protection factor (SPF) was calculated, as MED on protected skin/MED on unprotected skin. Results: The SPFs of the inorganic and organic Sunscreen, respectively, were reduced by 38% and 41% after 4 h and by 55% and 58% after 8 h. Conclusion: One application of either an inorganic or an organic Sunscreen reduced the erythema caused by UVB during a day with physical activity and bathing. After 8 h the Sunscreens still provided approximately 43% of the initial protective effect. This might simulate what happens during a day at the beach.
-
Sunscreen use related to uv exposure age sex and occupation based on personal dosimeter readings and sun exposure behavior diaries
Archives of Dermatology, 2005Co-Authors: Elisabeth Thieden, Peter A. Philipsen, Jane Sandbymoller, Hans Christian WulfAbstract:Objectives To examine during what behaviors people apply Sunscreen and to assess the relationship to UV exposure monitored by personal dosimetry and diaries. Design Open prospective observational study. Setting University hospital. Participants A convenience sample of 340 Danish volunteers: children, adolescents, indoor workers, sun worshippers, golfers, and gardeners (age range, 4-68 years). Intervention Subjects recorded Sunscreen use and sun-exposure behavior in diaries and carried personal, electronic UV dosimeters, measuring time-stamped UV doses continuously, during a median of 119 days covering 346 sun-years (1 sun-year equals 1 subject participating during 1 summer season). Main Outcome Measures Associations between Sunscreen use and age, sex, skin type, occupation, sunburn, UV exposure doses, and behavior; and adequate application density and sun protection factor required to prevent sunburn. Results There were great variations in Sunscreen use, which was highly correlated with risk behavior (sunbathing or exposing the upper body) ( r = 0.39; P P P P ≤.03) and on sunburn days ( P 2 . Conclusion Days with Sunscreen correlated not with days without risk behavior, but with days “sunbathing with the intention to tan,” indicating that Sunscreens were used as tanning aids to avoid sunburn.
-
systemic absorption of the Sunscreens benzophenone 3 octyl methoxycinnamate and 3 4 methyl benzylidene camphor after whole body topical application and reproductive hormone levels in humans
Journal of Investigative Dermatology, 2004Co-Authors: Nadeem Rezaq Janjua, Brian Mogensen, Mette Henriksen, Niels E Skakkebaek, Annamaria Andersson, Jorgen Holm Petersen, Hans Christian WulfAbstract:Recent in vitro and animal studies have reported estrogen-like activity of chemicals used in Sunscreen preparations. We investigated whether the three Sunscreens benzophenone-3 (BP-3), octyl-methoxycinnamate (OMC), and 3-(4-methylbenzylidene) camphor (4-MBC) were absorbed and influenced endogenous reproductive hormone levels in humans after topical application. In this 2-wk single-blinded study 32 healthy volunteers, 15 young males and 17 postmenopausal females, were assigned to daily whole-body topical application of 2 mg per cm2 of basic cream formulation without (week 1) and with (week 2) the three Sunscreens at 10% (wt/wt) of each. Maximum plasma concentrations were 200 ng per mL BP-3, 20 ng per mL 4-MBC, and 10 ng per mL OMC for females and 300 ng per mL BP-3, 20 ng per mL 4-MBC, and 20 ng per mL OMC for men. All three Sunscreens were detectable in urine. The reproductive hormones FSH, LH were unchanged but minor differences in testosterone levels were observed between the 2 wk. A minor difference in serum estradiol and inhibin B levels were observed in men only. These differences in hormone levels were not related to Sunscreen exposure.
-
Sunscreens used at the beach do not protect against erythema a new definition of spf is proposed
Photodermatology Photoimmunology and Photomedicine, 1997Co-Authors: Hans Christian Wulf, I M Stender, Jorgen LockandersenAbstract: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 finding 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.
Maxine J. Mccall - One of the best experts on this subject based on the ideXlab platform.
-
Long-term exposure to commercially available Sunscreens containing nanoparticles of TiO 2 and ZnO revealed no biological impact in a hairless mouse model
Particle and Fibre Toxicology, 2016Co-Authors: Megan J. Osmond-mcleod, Yalchin Oytam, Fariborz Sobhanmanesh, Gavin Greenoak, Elizabeth F. Mcinnes, Jason K. Kirby, Anthony Rowe, Maxine J. MccallAbstract:The application of Sunscreen is a critical component of a sun-safe strategy, however the possibility of unexpected, adverse outcomes resulting from long-term use of Sunscreens containing nanoparticles of titanium dioxide (TiO2) and zinc oxide (ZnO) has not yet been examined. Here, immune-competent hairless mice were exposed over a 36-week period to weekly topical applications of Sunscreens containing nanoparticles of ZnO or TiO2, or no metal oxide nanoparticles, with or without subsequent exposure to ultraviolet radiation (UVR). Control groups received no Sunscreen applications, with or without UVR. Mice exposed to UVR in the absence of Sunscreen developed statistically significant incidences of histologically-diagnosed malignant and benign skin neoplasms, whereas no statistically significant adverse biological outcomes were found in mice treated with the Sunscreens containing ZnO or TiO2 nanoparticles. Elevated levels of Ti were detected in the livers of mice treated with Sunscreen containing TiO2 nanoparticles compared to untreated control, but total Zn concentrations did not significantly alter in any major organs except for the skin of mice treated with ZnO Sunscreen. Exposure to UVR did not have a significant impact on examined tissue concentrations of Zn or Ti. Few to no transcriptional changes were found in ZnO or TiO2-treated groups, but mice treated with the Sunscreen containing only organic filters showed substantial gene disregulation. Taken together with previous work, this long-term study provided no basis to avoid the use of Sunscreens containing metal oxide nanoparticles.
-
dermal absorption and short term biological impact in hairless mice from Sunscreens containing zinc oxide nano or larger particles
Nanotoxicology, 2014Co-Authors: Megan J Osmondmcleod, Yalchin Oytam, Jason K. Kirby, Laura Gomezfernandez, Brent Baxter, Maxine J. MccallAbstract:Previous studies have shown no, or very limited, skin penetration of metal oxide nanoparticles following topical application of Sunscreens, yet concerns remain about their safety compared to larger particles. Here, we assessed the comparative dermal absorption of a traceable form of Zn ((68)Zn) from (68)ZnO nano-sized and larger particles in Sunscreens. Sunscreens were applied to the backs of virgin or pregnant hairless mice over four days. Control groups received topical applications of the Sunscreen formulation containing no ZnO particles, or no treatment. Major organs were assessed for changes in (68)Zn/(64)Zn ratios, (68)Zn tracer and total Zn concentrations. Short-term biological impact was assessed by measuring levels of serum amyloid A in blood, and by performing whole-genome transcriptional profiling on livers from each group. Increased concentrations of (68)Zn tracer were detected in internal organs of mice receiving topical applications of (68)ZnO (nano-sized and larger particles), as well as in fetal livers from treated dams, compared with controls. Furthermore, concentrations of (68)Zn in organs of virgin mice treated with Sunscreen containing (68)ZnO nanoparticles were found to be significantly higher than in mice treated with Sunscreen containing larger (68)ZnO particles. However, no ZnO-mediated change in total Zn concentration in any of the major organs was observed. Thus, despite (68)Zn absorption, which may have been in the form of soluble (68)Zn species or (68)ZnO particles (not known), Zn homeostasis was largely maintained, and the presence of ZnO particles in Sunscreen did not elicit an adverse biological response in the mice following short-term topical applications.
-
small amounts of zinc from zinc oxide particles in Sunscreens applied outdoors are absorbed through human skin
Toxicological Sciences, 2010Co-Authors: Yalchin Oytam, Maxine J. Mccall, Brian Gulson, Michael J Korsch, Laura Gomez, Philip S Casey, Alan Taylor, Malcolm T Mcculloch, Julie TrotterAbstract:Metal oxide nanoparticles are commonly used in personal-care formulations as protective agents against exposure to ultraviolet radiation. Although previous research has concluded that nanoparticles do not penetrate healthy skin, it remains contentious whether this conclusion holds under normal conditions of Sunscreen use. Humans (n = 20) were exposed to Sunscreens containing zinc oxide (ZnO) particles to determine if Zn from the particles was absorbed through skin over five consecutive days under outdoor conditions. Two Sunscreens were tested-"nano Sunscreen" containing 19-nm nanoparticles and "bulk Sunscreen" containing > 100-nm particles. Venous blood and urine samples were collected 8 days before exposure, twice daily during the trial, and 6 days post-exposure. As the first application in nanotechnology studies, stable isotope tracing was used where the ZnO, enriched to > 99% with the stable isotope (68)Zn, allowed dermally absorbed zinc to be distinguished from naturally occurring zinc. The overwhelming majority of applied (68)Zn was not absorbed, although blood and urine samples from all subjects exhibited small increases in levels of tracer (68)Zn. The amount of tracer detected in blood after the 5-day application period was ∼1/1000 th that of total Zn in the blood compartment. Tracer levels in blood continued to increase beyond the 5-day application phase in contrast to those in urine. Levels of (68)Zn in blood and urine from females receiving the nano Sunscreen appeared to be higher than males receiving the same treatment and higher than all subjects receiving the bulk Sunscreen. It is not known whether (68)Zn has been absorbed as ZnO particles or soluble Zn or both.
Antonio Tovarsanchez - One of the best experts on this subject based on the ideXlab platform.
-
repellency and mortality effects of Sunscreens on the shrimp palaemon varians toxicity dependent on exposure method
Chemosphere, 2020Co-Authors: Cristiano V M Araujo, Araceli Rodriguezromero, Marco Fernandez, Erica Sparaventi, Marina Marquez Medina, Antonio TovarsanchezAbstract:Abstract Contamination by Sunscreens has become a serious environmental problem due to the increasing use of these products in coastal regions. Their complex chemical composition supposes an input of different chemical compounds capable of producing toxic effects and repelling organisms. The aim of the current study was to experimentally check the repellency of three commercial Sunscreens [A (lotion), B (gel) and C (milk spray)] by assessing the escape (displacement towards areas with lower Sunscreen levels) of the estuarine shrimp Palaemon varians exposed (4 h) to a gradient (0-300 mg/L) of the Sunscreens in a heterogeneous non-forced exposure scenario. Additionally, mortality and immobility (72 h) were checked in a traditional forced exposure scenario. Considering that the toxicity of Sunscreens is a little controversial regarding their chemical availability in the medium, two different methods of Sunscreen solubilisation were tested: complete homogenization and direct immersion. Very low mortality was observed in the highest concentration of Sunscreens A and C applied by direct immersion; however, for Sunscreen B, the main effect was the loss of motility when homogenization was applied. Repellency was evidenced for two Sunscreens (A and B) applied by direct immersion. The homogenization in the medium seemed to lower the degree of repellency of the Sunscreens, probably linked to the higher viscosity in the medium, preventing the motility of shrimps. By integrating both short-term responses (avoidance and mortality/immobility), the PID (population immediate decline) calculated showed that avoidance might be the main factor responsible for the reduction of the population at the local scale.
Antony R Young - One of the best experts on this subject based on the ideXlab platform.
-
sub optimal application of a high spf Sunscreen prevents epidermal dna damage in vivo
Acta Dermato-venereologica, 2018Co-Authors: Antony R Young, Robert Sarkany, Graham I. Harrison, Karl P. Lawrence, J Greenaway, Thierry Douki, Goulven Josse, Emmanuel Questel, Christelle Monteil, Ana Beatris RossiAbstract:: The cyclobutane pyrimidine dimer (CPD) is a potentially mutagenic DNA photolesion that is the basis of most skin cancers. There are no data on DNA protection by Sunscreens under typical conditions of use. The study aim was to determine such protection, in phototypes I/II, with representative Sunscreen-user application. A very high SPF formulation was applied at 0.75, 1.3 and 2.0 mg/cm2. Unprotected control skin was exposed to 4 standard erythema doses (SED) of solar simulated UVR, and Sunscreen-treated sites to 30 SED. Holiday behaviour was also simulated by UVR exposure for 5 consecutive days. Control skin received 1 SED daily, and Sunscreen-treated sites received 15 (all 3 application thicknesses) or 30 (2.0 mg/cm2) SED daily. CPD were assessed by quantitative HPLC-tandem mass spectrometry (HPLC-MS/MS) and semi-quantitative immunostaining. In comparison with unprotected control sites, Sunscreen significantly (p ≤ 0.001-0.05) reduced DNA damage at 1.3 and 2.0 mg/cm2 in all cases. However, reduction with typical Sunscreen use (0.75 mg/cm2) was non-significant, with the exception of HPLC-MS/MS data for the 5-day study (p <0.001). Overall, these results support Sunscreen use as a strategy to reduce skin cancer, and demonstrate that public health messages must stress better Sunscreen application to get maximal benefit.
-
ultraviolet radiation and the skin photobiology and Sunscreen photoprotection
Journal of The American Academy of Dermatology, 2017Co-Authors: Antony R Young, Joel Claveau, Ana Beatris RossiAbstract:The efficacy of Sunscreens can be measured by different methods, involving in vitro, ex vivo, or in vivo techniques. There is a need for a worldwide standardization of these methods to avoid misunderstanding and confusion among Sunscreen users. The clinical benefits of Sunscreens have been demonstrated in randomized controlled trials that established the role of Sunscreens in the prevention of actinic keratoses, squamous cell carcinomas, nevi, and melanomas. Sunscreens also prevent photoimmunosuppression and signs of photoaging. Continued efforts in public education on the proper application of Sunscreens and the practice of photoprotection in general are needed.
-
Photoprotection and vitamin D status
Journal of Photochemistry and Photobiology B-biology, 2010Co-Authors: Peter Springbett, Surhi Buglass, Antony R YoungAbstract:The adverse effects of solar ultraviolet radiation on the skin are well documented, especially in fair-skinned people. These can be ameliorated by photoprotection strategies advocated by many public health bodies and typically include sun avoidance, Sunscreen use and clothing. The UVB waveband which is the main cause of all adverse effects investigated in the laboratory to date is also the waveband for vitamin D photosynthesis which is the only established benefit of solar exposure. This is especially important because solar UVB is the main source of vitamin D for most people. There is increasing evidence that vitamin D plays a much greater role in human health than was previously thought. This has given rise to concerns that photoprotection, especially Sunscreen use, could adversely affect vitamin D status and human health. Furthermore, it is stated that people with heavily pigmented skins often have poor vitamin D status because of photoprotection by melanin. In this paper we review the effect of photoprotection strategies and pigmentation on vitamin D status. Clothing can clearly be very effective at inhibiting vitamin D synthesis. Sunscreens are effective in theory and some limited human studies support this. However, most studies show little or no effect and the most likely reason for this is that Sunscreens have not been applied in the manner that was used to determine their labelled index of protection against sunburn. This could change in the future if public health campaigns and the Sunscreen industry are successful in encouraging the public to apply Sunscreens more liberally and/or use much higher levels of labelled protection. The role of melanin on vitamin D status is not clear and requires further investigation.
Steven Q Wang - One of the best experts on this subject based on the ideXlab platform.
-
current status of the Sunscreen regulation in the united states 2011 food and drug administration s final rule on labeling and effectiveness testing
Journal of The American Academy of Dermatology, 2011Co-Authors: Steven Q WangAbstract:ANPR: Advance Notice of Proposed Rulemaking CW: critical wavelength FDA: Food and Drug Administration MED: minimal erythema dose PPD: persistent pigment darkening SPF: sun protection factor TEA: Time and Extent Application INTRODUCTION On June 17, 2011, the US Food and Drug Administration (FDA) issued its long awaited final ruling on labeling and effectiveness testing of Sunscreen products in the United States. At the same time, the FDA published 3 other documents: (1) a Draft Enforcement Guidance for Industry document, further explaining the final rule, (2) a Proposed Rule on Sunscreens with sun protection factors (SPFs) greater than 50, seeking additional comments on its proposal to cap SPF at 501, and (3) an Advance Notice of Proposed Rulemaking (ANPR), requesting information about alternative dosage forms of Sunscreen products (ie, sprays), and proposing that certain dosage forms (wipes, towelettes, powders, body washes, and shampoos) to be considered not eligible for review under the Sunscreen monograph process. Only the final rule regarding labeling and testing of Sunscreens has been approved, whereas the regulations and suggestions in the other 3 documents, hence the Sunscreen monograph itself, have not been finalized. This announcement signals a recognition by the FDA of the clinical benefits of photoprotection, with Sunscreens as one of the measures. Furthermore, it provides a much anticipated standard for testing and labeling UVA protection in Sunscreens.
-
current Sunscreen controversies a critical review
Photodermatology Photoimmunology and Photomedicine, 2011Co-Authors: Mark E Burnett, Steven Q WangAbstract:Background/purpose: Sunscreens are believed to be a valuable tool in providing photoprotection against the detrimental effects of UV radiation, a known carcinogen. However, a number of controversies have developed regarding their safety and efficacy. This review summarizes the relevant studies surrounding these controversies. Methods: Evidence of the prevention of skin cancer, an oft-cited reason for Sunscreen use, was examined as it pertains to squamous cell carcinoma, basal cell carcinoma and melanoma. We also reviewed studies examining the effects of Sunscreen on the synthesis of vitamin D, an essential nutrient whose role in health and disease continues to grow. Lastly, we analyzed studies surrounding the safety and toxicity of oxybenzone, retinyl palmitate and nanoparticles of zinc oxide (ZnO) and titanium dioxide (TiO2). Results: The overwhelming majority of available data is drawn from studies conducted using antiquated Sunscreen formulations. Nonetheless, our research revealed that topical use of Sunscreen protects against squamous cell carcinoma, does not cause vitamin D deficiency/insufficiency in practice and has not been demonstrated to adversely affect the health of humans. Conclusion: Given the established benefits of UV protection, the use of Sunscreens remains an important part of an overall photoprotective strategy. Future Sunscreens with improved formulation should ideally offer superior protection. With increased usage of Sunscreen by the public, continuous and vigilant monitoring of the overall safety of future products is also needed.
-
in vitro assessments of uva protection by popular Sunscreens available in the united states
Journal of The American Academy of Dermatology, 2008Co-Authors: Steven Q Wang, Joseph W Stanfield, Uli OsterwalderAbstract:Background The importance of adequate ultraviolet A (UVA) protection has become apparent with improved understanding of the mechanism of UVA-induced damage to tissues. Currently in the United States, there is no regulation on testing and labeling of Sunscreens for UVA protection. In August 2007, the Food and Drug Administration (FDA) addressed this issue in a proposed rule. Objectives We sought to assess in vitro the degree of UVA protection provided by 13 popular Sunscreen products that are commercially available in the United States. Method Thirteen Sunscreen products were purchased. UVA protection of each product was measured and assessed with 3 in vitro UVA labeling indices: (1) the FDA Proposed Amendment of Final Monograph, August 27, 2007; (2) European Commission Recommendation—the Colipa and critical wavelength methods; (3) and United Kingdom's Boots star rating system. Results Based on the new FDA-proposed guidelines, 8 products achieved the medium protection category, and 5 products achieved high protection. The latter 5 products also fulfilled the UVA protection based on the Colipa guideline desired by the European Commission Recommendation. Nine products achieved the desired critical wavelength value of 370 or higher. Based on the United Kingdom's Boots star rating system, 6 products achieved a rating of 3 stars, and the remaining 7 products achieved no star rating. Limitations The study only evaluated a small number of Sunscreen products, and only in vitro methods were used to assess the degree of UVA protection. Conclusions The majority of the tested Sunscreens in this study offered a medium degree of UVA protection. Compared with the Sunscreens in the past, this study shows that UVA protection of Sunscreens has improved. Sunscreens with avobenzone and octocrylene provided a higher degree of UVA protection. Globally, there is no uniform standard on testing and labeling Sunscreens for UVA protection. In the United States, the FDA has just started to create a much-needed standard. This effort is necessary to educate the public better on how to choose products with adequate UVA protection
