Effect of environmental factors on solar UV measurements

For a correct understanding and interpretation of solar UV data sampled at ground level, several practical and theoretical problems of measurement are shown. In particular, the comparison between either different sites or instruments is thoroughly analysed, and the effects due to O3 level, albedo and cloudiness are discerned. The impact of clouds and their position with respect to the sun on the observation carried out both by spectral and broad-band instruments are also examined.

PCR-based methodology for the determination of the photoprotection afforded by sunscreen application

We have applied a PCR-based methodology to study the DNA damage induced by UV-A, UV-B and sunlight itself. Our results, employing a cell-free system, indicate that UV-B (310 nm) is approximately 30-fold more potent at inhibiting DNA synthesis than UV-A (365 nm). We were also able to show that 20 min of sunlight exposure on a summer day induced DNA damage capable of inhibiting DNA synthesis. Hence, this methodology has a sensitivity suitable to detect biologically relevant doses of UV light. In addition, we propose that this technique may be suitable to assess the relative photoprotection of commercially available sunscreens. We present here preliminary data on the photoprotection afforded by the topical application of sunscreen. This photoprotection was measured by a reduction in the subsequent UV-B- and UV-A-induced DNA damage when sunscreen was applied. Our results demonstrate that the particular sunscreen tested was effective against both UV-B and UV-A. However, the estimated photoprotective factor of the sunscreen (against both UV-A and UV-B) was approximately tenfold less than the stated Sun Protection Factor (SPF) of 25. This methodology may also be useful in identifying new photoprotective agents by assessing their relative value as UV-B and UV-A absorbing agents.

Reduction of minimal erythema dose by sweating

BACKGROUND/AIMS

Solar ultraviolet (UV) radiation is the most important environmental risk factor for melanoma and non-melanoma skin cancer. It is known that tap water and saltwater baths have a photosensitizing capacity in subsequent UV irradiation of the skin. The aim of the present study was to determine the influence of sweating from heat or from physical activity on the photosensitivity of the skin.

METHODS

Minimal erythema dose to ultraviolet B (MED/UVB) was determined on the inner forearms of 22 healthy volunteers with a Saalmann Multi-tester. Sweating had been provoked by heat (sauna for 10 min) and, on another occasion, physical exercise (jogging for 15 min) followed by MED/UVB testing in a similar way.

RESULTS

Compared to baseline MED/UVB there was a highly significant decrease in MED/UVB of up to 31.6% (median 15.8%, mean 15.9% +/- 10.0) after 10 min in the sauna and up to 40.9% (median 16.3%, mean 17.2% +/- 12.5) after 15 min jogging (P < 0.0001).

CONCLUSION

Sweat influences the hydration of the horny layer of the skin, resulting in a decrease in reflection and dispersion of UV light. Moderate physical activities such as jogging and/or heat may facilitate erythema reaction. By sweating, outdoor workers and people practicing outdoor sports who are exposed to considerable amounts of solar UV radiation further increase their risk of sunburn.

Photoaging of human skin

Chronic sun exposure causes photoaging of human skin, a process that is characterized by clinical, histological and biochemical changes which differ from alterations in chronologically aged but sun-protected skin. Within recent years, substantial progress has been made in unraveling the underlying mechanisms of photoaging. Induction of matrix metalloproteinases as a consequence of activator protein (AP)-1 and nuclear factor (NF)-KB activation as well as mutations of mitochondrial DNA have been identified recently. This has increased our understanding of photoaging significantly and has led to new prophylactic and therapeutic strategies aimed at the prevention and repair of the detrimental effects of chronic sun-exposure on the skin.

Sun Protection is Fun! A skin cancer prevention program for preschools

Children and their caregivers are prime candidates for intervention to curb the rising incidence of skin cancer in the United States. Preschools provide a unique opportunity to influence the sun protection practices of parents and teachers on behalf of young children. Sun Protection is Fun!, a comprehensive skin cancer prevention program developed by The University of Texas M. D. Anderson Cancer Center in collaboration with The University of Texas-Houston Health Science Center School of Public Health, was introduced to preschools in the greater Houston area. The program's intervention methods are grounded in Social Cognitive Theory and emphasize symbolic modeling, vicarious learning, enactive mastery experiences, and persuasion. Program components include a curriculum and teacher's guide, videos, newsletters, handbooks, staff development, group meetings designed to encourage schoolwide changes to support the program, and sunscreen. The intervention map, including objectives for program development, implementation, and evaluation, is discussed.

Skin cancer in heart transplant recipients: risk factor analysis and relevance of immunosuppressive therapy

BACKGROUND

The frequency of skin tumors of all types and specifically of squamous cell carcinoma (SCC) is increased in heart transplantation (HT), but the predisposing risk factors are controversial.

METHODS AND RESULTS

We studied 300 patients (age 49+/-15 years, 258 men, mean follow-up 4.6 years, follow-up range 1 month to 12 years) who were receiving standard double (cyclosporin plus azathioprine) or triple (cyclosporin plus azathioprine plus prednisone) therapy. The first-year rejection score was calculated for endomyocardial biopsy samples (International Society for Heart and Lung Transplantation grade 0=0, 1A=1, 1B=2, 2=3, 3A=4, 3B=5, and 4=6) and used as an indirect marker of the level of immunosuppression. Multivariate analysis (Cox regression) included age at HT, sex, skin type, first-year rejection score, presence of warts and solar keratosis, lifetime sunlight exposure, and first-year cumulative dose of steroids. The incidence of skin tumors of all types increased from 15% after 5 years to 35% after 10 years after HT according to life-table analysis. Age at HT of >50 years (P:=0.03, RR=5.3), skin type II (P:=0.05, RR=2.6), rejection score of 19 (P:=0.003, RR=5.7), solar keratosis (P:=0.001, RR=6.9), and lifetime sunlight exposure of >30 000 hours (P:=0.0003, RR=7.6) were risk factors for SCC.

CONCLUSIONS

Older age at HT, light skin type, solar keratosis, greater sunlight exposure, and high rejection score in the first year were independently associated with an increased risk of SCC. The progressive increase in cancer frequency during follow-up and the association with high rejection scores suggest that both the length and level of immunosuppression may be relevant. Because cumulative immunosuppressive load is cumbersome to calculate, a high rejection score in the first year may provide a useful predictor for patients at risk.

The conjunctivitis of solar (actinic) prurigo

Solar (actinic) prurigo (SP) is an abnormal reaction to sunlight that affects mostly the Indian and mestizo populations of America, and is well known in Canada and the United States. It is quite common in Mexico, Central, and South America, although rare in Europe. It usually starts in childhood in both sexes and in about 30-50% of cases involves the oral and ocular mucosa. In this study we present the clinical and histopathologic conjunctival findings in 11 of 105 children with SP. Clinically the most important features were photophobia, some degree of pterygium, and pinguecula, hyperemia, Trantas' dots, hyaline exudate, and follicles. Histopathologically the changes were epithelial, such as epidermoid metaplasia and absence of goblet cells, and stromal changes, which were the most diagnostically relevant. These consisted of lymphocytic inflammatory infiltrates, usually with eosinophils, melanosis, and solar elastosis. We believe this constellation of criteria will be useful for a better characterization of SP.

Persistent increase in children's sun protection in a randomized controlled community trial

BACKGROUND

Reducing sun exposure during childhood may prevent skin cancer later in life. Sun protection increased immediately following implementation of the SunSafe multicomponent, community-based intervention delivered in 1996 through schools, day care centers, primary care offices, and beach recreation areas. Whether sun protection levels would remain higher than preintervention levels the following summer was unknown.

METHODS

A randomized controlled trial based in 10 New Hampshire towns addressed children's use of protective clothing, shade, and sunscreen at freshwater beach areas. The intervention was provided initially between March and May 1996. A brief project follow-up contact was provided to schools, day care centers, beaches, and primary care offices between March and May 1997 to restock intervention materials and to answer questions. Observations of 1490 children during June through August of 1997 were compared with observations made prior to any intervention between June and August of 1995.

RESULTS

In intervention towns, the proportion of children using at least some sun protection increased by 0.15 from 0.58 in 1995 to 0.73 in 1997 while the proportion in control towns increased by 0.03 (P = 0.033). This increase was due to more use of sunscreen, but not more use of protective clothing or shade. In 1997, care-givers of children in intervention towns reported receiving more sun protection information from school and health care sources than control town caregivers (62% versus 33%, P < 0.006).

CONCLUSIONS

In intervention communities, a higher proportion of children used sun protection in 1997 than at baseline. Increases from 1995 to 1997 were similar in magnitude to short-term increases between 1995 and 1996 that we have been previously reported.

Photocarcinogenesis: UVA vs UVB

Ultraviolet B and A radiations (respective wavelength ranges 280-315 and 315-400 nm) are present in sunlight at ground level. The ultraviolet radiation does not penetrate any deeper than the skin and has been associated with various types of human skin cancers. The carcinogenicity of UVB radiation is well established experimentally and, to a large extent, understood as a process of direct photochemical damage to DNA from which gene mutations arise. Although UVA is generally far less carcinogenic than UVB radiation, it is present more abundantly in sunlight than UVB radiation (> 20 times radiant energy) and can, therefore, contribute appreciably to the carcinogenicity of sunlight. In contrast to UVB, UVA radiation is hardly absorbed by DNA. Hence, the absorption by other molecules (endogenous photosensitizers) becomes more important, thus radicals and, more specifically, reactive oxygen species can be generated that can damage DNA, membranes, and other cellular constituents. These photochemical differences between UVA and UVB radiations are reflected in differences in cellular responses and carcinogenesis.

Acneiform dermatoses

Acneiform dermatoses are follicular eruptions. The initial lesion is inflammatory, usually a papule or pustule. Comedones are later secondary lesions, a sequel to encapsulation and healing of the primary abscess. The earliest histological event is spongiosis, followed by a break in the follicular epithelium. The spilled follicular contents provokes a nonspecific lymphocytic and neutrophilic infiltrate. Acneiform eruptions are almost always drug induced. Important clues are sudden onset within days, widespread involvement, unusual locations (forearm, buttocks), occurrence beyond acne age, monomorphous lesions, sometimes signs of systemic drug toxicity with fever and malaise, clearing of inflammatory lesions after the drug is stopped, sometimes leaving secondary comedones. Other cutaneous eruptions that may superficially resemble acne vulgaris but that are not thought to be related to it etiologically are due to infection (e.g. gram-negative folliculitis) or unknown causes (e.g. acne necrotica or acne aestivalis).

Efficacy of short-course oral prednisolone in polymorphic light eruption: a randomized controlled trial

BACKGROUND

Polymorphic light eruption (PLE) is the most common so-called idiopathic photosensitivity disorder and affects up to 15% of the population in the U.K.; brief courses of systemic steroids have been tried and anecdotally have apparently been dramatically effective in the treatment of acute attacks.

OBJECTIVES

To assess the efficacy and safety of a short course of moderate-dose oral prednisolone used from the earliest onset of the eruption in the treatment of PLE.

METHODS

The study was double-blind placebo-controlled, all patients being given both prednisolone and placebo, but randomized to take either one or the other from the earliest sign of onset of rash; if within 48 h there was no improvement, they transferred to the other medication. Each participant also applied a broad-spectrum, highly protective sunscreen 2-hourly during sun exposure, continued his or her usual degree of exposure after any development of PLE, and kept a diary noting details of the eruption, amount of exposure, weather conditions and any adverse events. Statistical analysis was performed by means of the non-parametric log rank test based on Kaplan-Meier plots and bootstrapped confidence intervals (CIs) for the means, using the time in days for the itch and rash to clear as the end-points.

RESULTS

Twenty-one patients entered the study but only 10 required medication. Eight who took prednisolone first and remained on it or transferred to it from placebo all improved, with the itch settling fully within a mean 2.8 days of starting the prednisolone and the rash clearing by 4.2. In the two who took placebo first and remained on it, the itch took a mean 5.4 days to settle and the rash a mean 7.8. No patient who started with prednisolone changed to placebo. Thus, the prednisolone as randomized was better than placebo at settling both the itch (mean 2. 6 days less, CI 0.7-4.0, P = 0.015) and rash (mean 3.6 days less, CI 0.6-6.1, P = 0.036); only one patient experienced mild adverse effects of transient gastrointestinal upset and depressed mood.

CONCLUSIONS

The acute eruption of PLE is likely to respond rapidly to short courses of prednisolone therapy given from the earliest onset of the condition, and the treatment is safe.

Evaluation of primary prevention initiatives for skin cancer: a review from a UK perspective

To ensure effective primary prevention of skin cancer, aimed at changing behaviour in the sun, and ultimately at reducing the incidence and mortality rates from skin cancer, sufficient information needs to be known about the relationship between sun exposure and skin cancer, the effectiveness of sun protection measures, and the acceptability and uptake of protective measures by the general public. This review specifically addresses the quality and outcome of studies designed to evaluate the impact of primary prevention initiatives in the U.K. Four main areas of concern are highlighted: (i) teenage behaviour in the sun is difficult to change; (ii) fashion, in part, dictates adult and adolescent behaviour in the sun; (iii) there are practical problems related to response rates, follow-up and interpretation of self-reported behaviour; and (iv) a strategy for primary prevention in the U.K. may be falsely based on the experience and results of Australian and American programmes. Standardized methods for monitoring general population behaviour are needed in the U.K. Evaluation of interventions targeting specific groups, especially parents and young children, and the relative costs of different strategies should be reported. Primary prevention messages and strategies should be adapted to the type of ultraviolet radiation exposure experienced, and the overall low risk of melanoma, while addressing controversies on the health effects of sun exposure and sun screens.

Use of sunscreen is linked with elevated naevi counts in Israeli school children and adolescents

Epidemiological evidence indicates that a fair complexion and exposure to solar radiation in early years contribute to the proliferation of naevi and subsequent melanoma risk. To determine whether protection from sunlight is associated with lower naevi counts, we examined the prevalence and risk factors of naevi in a sample of Israeli school pupils. Whole body counts of naevi were recorded in 974 out of 1312 (74.2%) recruited pupils (7 and 12 year olds) from Ramat-Gan and Jerusalem. Host characteristics and habits of sun exposure were obtained using questionnaires. In each age group and geographic area, the mean whole body naevi counts, adjusted for confounders, were higher among males, pupils of European-American descent, and those susceptible to sunburn. The contributions to naevi risk of fair skin colour and frequent recreational sun exposure were higher among 7 year olds. Regular sunscreen use contributed to the naevi risk for both age strata in Ramat-Gan (at age 7, rate ratio [RR] = 1.7, 95% confidence interval [CI] = 1.3-2.2; at age 12, RR = 1.5, 95% CI = 1.1-2.1). Among the younger age group in Ramat-Gan, even seldom compared with no use of sunscreen was associated with higher naevi counts (RR= 1.5, 95% CI = 1.2-2.0). Similar patterns were noted with the pupils from Jerusalem. In conclusion, the elevated naevi count with increased sunscreen use indicates that sunscreens apparently do not modify the genetic predisposition to naevi proliferation. For better protection of children and adolescents, including those who use sunscreens, from the naevogenic effect of solar radiation, they should be encouraged to limit their exposure and wear protective clothing when in the sun.

Do forecasts of UV indexes influence people's outdoor behaviour?

OBJECTIVE

To investigate Australian adults' awareness of the ultraviolet (UV) indexes forecast in the media, and whether these UV forecasts influence their behaviour in the sun.

METHODS

A self-administered questionnaire was used on two occasions in 1997 to ask about knowledge of UV indexes shown in the media and about possible influence on outdoor behaviour.

SETTING AND PARTICIPANTS

Participants were 977 residents (423 men; 554 women) of Nambour originally randomly selected in 1986 from the electoral roll, who have been followed up subsequently.

RESULTS

The majority of people--92% of men and 86% of women--reported having seen or heard the UV indexes forecast during summer. Of these, significantly fewer men (107; 28%) than women (209; 46%) reported that their outdoor behaviour was influenced by knowledge of the forecast (p = 0.001). Neither age nor skin type, nor history of sunburns or skin cancer, affected knowledge of UV forecasts or their influence on behaviour.

CONCLUSIONS AND IMPLICATIONS

Although most people are aware of the forecasts of UV indexes in the media, the majority do not take them into account in their outdoor behaviour. Compared with women, men were more aware of, but less influenced by, forecasts of UV indexes. Better communication of the implications of the UV indexes is needed, particularly to men, if they are to adapt their outdoor behaviour to improve their sun protection.

Oral precancer and cancer: etiology, clinical presentation, diagnosis, and management

Oral and oropharyngeal cancers represent 3% of all cancers in the United States annually, with nearly 50% of people diagnosed with oral and oropharyngeal cancers dying as a result of the disease. Because the dental practitioner is in an ideal position for recognizing any abnormality of the oral mucosa, he or she is involved in the battle against oral cancer by helping establish the diagnosis at an early stage. This article presents the clinical appearance, explains the origins, and describes steps for the management of oral precancer and cancer.

Collagen loss in photoaged human skin is overestimated by histochemistry

It is well known that photoaged skin is characterized by increases in dermal matrix components that include glycosaminoglycans, proteoglycans and masses of abnormal elastic fibers accompanied by substantial collagen loss. Histochemical staining of such tissue gives the impression of "massive" loss of collagen and its replacement by these other matrix components. Early biochemical studies have lent support to this notion with a reported decrease in total collagen of approximately 45% compared to protected skin. More recent studies report considerably less, but varying, amounts of collagen loss. Rarely have the two approaches, histochemistry and biochemical analysis, been used in the same study to examine the same tissue. In this study, collagen loss was quantified biochemically in paired biopsies from sun-protected and sun-exposed arm skin of moderately photoaged female subjects (age 51-77 years). The values obtained were compared with histochemical and immunochemical findings. Quantitatively, collagen loss on a per mg protein basis was small compared to the histochemical appearance.