Determinants of skin sensitivity to solar irradiation

The impact of sunlight exposure on brain structural markers in the UK Biobank

Sunlight is closely intertwined with daily life. It remains unclear whether there are associations between sunlight exposure and brain structural markers. General linear regression analysis was used to compare the differences in brain structural markers among different sunlight exposure time groups. Stratification analyses were performed based on sex, age, and diseases (hypertension, stroke, diabetes). Restricted cubic spline was performed to examine the dose-response relationship between natural sunlight exposure and brain structural markers, with further stratification by season. A negative association of sunlight exposure time with brain structural markers was found in the upper tertile compared to the lower tertile. Prolonged natural sunlight exposure was associated with the volumes of total brain (β: - 0.051, P < 0.001), white matter (β: - 0.031, P = 0.023), gray matter (β: - 0.067, P < 0.001), and white matter hyperintensities (β: 0.059, P < 0.001). These associations were more pronounced in males and individuals under the age of 60. The results of the restricted cubic spline analysis showed a nonlinear relationship between sunlight exposure and brain structural markers, with the direction changing around 2 h of sunlight exposure. This study demonstrates that prolonged exposure to natural sunlight is associated with brain structural markers change.

Skin biophysical properties including impaired skin barrier function determine ultraviolet sensitivity

BACKGROUND

The levels of burning susceptibility to ultraviolet (UV) radiations are affected by various factors, including Fitzpatrick skin types, skin color, sex, and ethnicity. However, studies on the relationship between skin biophysical properties and erythemal responses to UV radiations are rare.

OBJECTIVE

This study aimed to investigate biophysical properties of the skin that determined individual skin sensitivity to UV radiation.

METHODS

As an indicator of skin sensitivity to UV radiation, Korean women were subjected to minimal erythema dose (MED) testing. The skin biophysical properties, such as skin hydration, transepidermal water loss (TEWL) were measured. MED were also evaluated in further variations in the skin, including barrier disruption.

RESULTS

A significant negative correlation was observed between TEWL and MED. With an increase in TEWL, that represents reduced skin barrier function, skin UV sensitivity also increased. Artificial alteration of skin conditions also changed erythemal response to UV radiation. When the skin barrier was disrupted, MED significantly decreased, indicating increased skin UV sensitivity. It is hypothesized that the altered penetration of UV radiation into the stratum corneum under the respective skin conditions caused different erythema reactions.

CONCLUSION

For the first time in a clinical study, the skin biophysical properties, including skin barrier function, were found to have significant effects on skin sensitivity to UV radiation. This finding could help predict individual susceptibility to UV damage. Therefore, skincare products that improve skin conditions associated with UV sensitivity, as well as sunscreen are important for protection against the hazards of UV radiation.

A pilot study evaluating the efficacy and tolerability of a comprehensive, hydrating topical antioxidant developed specifically for men

Introduction

There is growing interest in skincare products designed for men. This pilot study evaluated the efficacy and tolerability of a comprehensive antioxidant product in men.

Methods

This 12‐week study evaluated improvements from baseline in erythema, lines/wrinkles, skin tone, texture, brightness, dryness/flaking and pores (6‐point scale), global improvements (5‐point scale), and sebum levels following daily application in males with mild to moderate photodamaged skin. Subject self‐assessments and adverse events (AEs) were captured.

Results

Twenty‐two subjects completed the study. Early mean percent improvements from baseline were demonstrated in all categories at week 4 with visible improvements in skin tone (29%; p = .0001) and pores (28%; p < .0001). Reductions in skin surface sebum levels (forehead region) from baseline were demonstrated at 8 (p < .0001) and 12 (p < .0003) weeks. Ninety‐six percent of subjects reported overall visible improvement of their skin and that the study product calmed/soothed skin, reducing redness and irritation after shaving. One subject reported mild dryness.

Conclusion

Once daily application of a comprehensive topical antioxidant designed for men led to significant improvements in skin appearance, substantial reductions in skin surface sebum levels, and was well tolerated with a high level of subject satisfaction over 12 weeks.

The effect of Vitamin C on melanin pigmentation - A systematic review

Vitamin C, also known as ascorbic acid, is used as a treatment modality in depigmentation of hyperpigmented spots on the skin and gingiva. This systematic review discusses the studies conducted to assess the effect of Vitamin C on melanin pigmentation. The primary objective was to evaluate the effect of Vitamin C on melanin pigmentation. The secondary objective was to analyze the effect of Vitamin C administration on melanin pigmentation. An electronic database search was conducted from the following databases: PubMed, EBSCOhost, ScienceOpen, EMBASE and Google Scholar. Randomized controlled trials, experimental studies, case-control studies and cohort studies published in peer-reviewed journals in English language were included. Case reports, case series, animal model studies, in vitro studies, studies where Vitamin C was used along with other agents and unpublished research were excluded. Out of 22,580 studies, only 7 studies satisfied the selection criteria. Data extraction sheet was prepared, and the studies were analyzed. Out of the 7 studies analyzed, 1 was a randomized controlled trial and 6 were experimental studies. Vitamin C has been used widely as a depigmenting agent in dermatology. However, there are limited studies conducted on the use of Vitamin C for gingival depigmentation.

Gender differences in cutaneous melanoma: Demographics, prognostic factors, and survival outcomes

Several recent studies have reported a considerably higher overall survival (OS) rate in females in various geographic regions This study further investigates the characteristics of melanoma that contribute to OS of women residing in the United States. Chi-square, Kaplan-Meier, and Cox regression models were used to analyze differences in demographics, treatment, and survival of invasive cutaneous melanoma in men and women diagnosed from 2004 to 2016 in the National cancer database. In 316 966 patients met inclusion criteria. Men had a significantly higher median age of diagnosis at 61 years (interquartile range or IQR: 51-72) in comparison to women where the median age of diagnosis was 55 years (IQR: 43-68) (P < .0001). The most common primary site for men was the trunk (35.5%), whereas the lower extremities were the most common primary site for women (30.3%). Women had a higher 5 year (82.6%) and 10 year (73.1%) OS compared to 5 year and 10 year OS of 72.2% and 58.7%, respectively, in men (P < .0001). When adjusting for confounders, female gender was independently associated with improved OS (ref: male HR = 0.791; 95% confidence interval 0.773-0.809; P < .0001). Overall, we conclude that female gender is an independent favorable prognostic factor for melanoma survival.

Ultraviolet Radiation Exposure and the Risk of Herpes Zoster in Three Prospective Cohort Studies

OBJECTIVE

To examine the association between ultraviolet radiation (UVR) exposure and the risk of herpes zoster (HZ) in 3 prospective cohorts.

PATIENTS AND METHODS

We included 205,756 participants from the Health Professionals Follow-up Study (HPFS; 1986-2008), Nurses' Health Study (NHS; 1996-2012), and Nurses' Health Study II (NHS II; 1991-2013). Ambient UVR exposure was based on updated geocoded address histories linked with a high-resolution spatiotemporal ultraviolet model. Incident HZ cases were identified by self-reported clinician diagnosis. Sunburn history and medical, lifestyle, and dietary factors were assessed using biennial questionnaires. Multivariable Cox proportional hazards models were used.

RESULTS

A total of 24,201 cases of HZ occurred during 3,626,131 person-years. Ambient UVR exposure was associated with a higher risk of HZ in men (HPFS: multivariable-adjusted hazard ratio [MVHR] comparing highest vs lowest quintiles, 1.14; 95% CI, 1.02-1.29; P=.03 for trend) but not in women (NHS: MVHR, 0.99; 95% CI, 0.93-1.05; NHS II: MVHR, 0.96; 95% CI, 0.90-1.03). A higher lifetime number of severe sunburns was associated with a higher risk of HZ in all cohorts (HPFS: MVHR for ≥10 sunburns vs none, 1.08; 95% CI, 0.96-1.20; P=.02 for trend; NHS: MVHR, 1.14; 95% CI, 1.05-1.22; P=.01 for trend; NHS II: MVHR, 1.13; 95% CI, 1.00-1.28; P<.001 for trend).

CONCLUSION

Ambient UVR exposure was associated with a higher risk of HZ in men but not in women. A history of severe sunburn was associated with a modest increased risk of HZ in men and women, possibly because of immunosuppression from overexposure to the sun.

Characteristics of keratinocyte carcinomas in Hispanics compared to non-Hispanic whites: A retrospective 5-year study

BACKGROUND

Hispanics are one of the fastest growing populations in the United States. Few studies have characterized the patterns of keratinocyte carcinoma presentation in Hispanics.

OBJECTIVE

The study aimed to compare the clinical and histologic characteristics of keratinocyte carcinomas in Hispanics and non-Hispanic whites.

MATERIALS AND METHODS

A five-year retrospective chart review was conducted at a single academic center to identify all histologically-confirmed cases of keratinocyte carcinomas. Tumor characteristics were then compared between Hispanics and non-Hispanic whites.

RESULTS

A total of 197 tumors were identified of which 76% occurred in non-Hispanic whites and 24% in Hispanics. Tumor diameter was not larger and histologic subtype was not more aggressive in Hispanics compared to non-Hispanic whites. Age of diagnosis of basal cell carcinoma was younger among Hispanics compared to non-Hispanic whites (P < .05).

CONCLUSION

Hispanics were not more likely to present with more high-risk keratinocyte carcinomas compared to non-Hispanic whites in terms of tumor diameter, differentiation and subtype.

Sex differences in the association of cutaneous melanoma incidence rates and geographic ultraviolet light exposure

BACKGROUND

Cutaneous melanoma (CM) incidence rates continue to increase, and the reasons are unknown. Previously, we reported a unique age-specific sex difference in melanoma that suggested additional causes other than solar ultraviolet (UV) radiation.

OBJECTIVE

This study attempted to understand whether and how UV radiation differentially impacts the CM incidence in men and women.

METHODS

CM data and daily UV index (UVI) from 31 cancer registries were collected for association analysis. A second dataset from 42 US states was used for validation.

RESULTS

There was no association between log-transformed female CM rates and levels of UVI, but there was a significant association between male rates and UVI and a significant association between overall rates and UVI. The 5-year age-specific rate-UVI association levels (represented by Pearson's coefficient ρ) increased with age in men, but age-specific ρ levels remained low and unchanged in women. The significant rate-UVI association in men and nonassociation in women was validated in a population of white residents of the United States.

LIMITATIONS

Confounders, including temperature and latitude, are difficult to separate from UVI.

CONCLUSIONS

Ambient UVI appears to be associated with melanoma incidence in males but not in females.

A case-control study of occupational sunlight exposure and renal cancer risk

Epidemiological evidence of a relationship between vitamin D and kidney cancer risk has been inconsistent despite experimental data indicating that vitamin D and its metabolites may inhibit carcinogenesis. Previously we reported an inverse association between renal cell carcinoma (RCC) risk and occupational ultraviolet (UV) exposure among European men. In this study, we examined the association between occupational UV exposure and RCC risk among US residents and investigated whether this association varied by race and sex. Lifetime occupational data for 1,217 RCC cases and 1,235 controls in a population-based case-control study, conducted from 2002 to 2007, were assessed for occupational UV exposure. We evaluated exposure metrics in quartiles based on control exposure levels and calculated associations between RCC risk and occupational UV exposure using unconditional logistic regression adjusted for sex, race, body mass index, smoking, hypertension, center, education, family history of cancer and dietary vitamin D intake. A general pattern of decreasing RCC risk with increasing UV exposure was observed. Cases had significantly lower cumulative occupational UV exposure than controls (fourth quartile vs. first: odds ratio = 0.74 [95% confidence interval = 0.56-0.99], p-trend = 0.03). Similar results were observed for other UV exposure metrics. The association with occupational UV exposure was stronger for women than for men, but did not differ by race. Our findings suggest an inverse association between occupational UV exposure and RCC, particularly among women. Given the sex finding discrepancies in this study versus our previous study, additional research is need to clarify whether the protective effects of occupational UV exposure and RCC risk are real.

Brazilian consensus on photoprotection

Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is located between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the south certainly makes Brazil one of the countries of the world with greater extent of land in proximity to the sun. The Brazilian coastline, where most of its population lives, is more than 8,500 km long. Due to geographic characteristics and cultural trends, Brazilians are among the peoples with the highest annual exposure to the sun. Epidemiological data show a continuing increase in the incidence of non-melanoma and melanoma skin cancers. Photoprotection can be understood as a set of measures aimed at reducing sun exposure and at preventing the development of acute and chronic actinic damage. Due to the peculiarities of Brazilian territory and culture, it would not be advisable to replicate the concepts of photoprotection from other developed countries, places with completely different climates and populations. Thus the Brazilian Society of Dermatology has developed the Brazilian Consensus on Photoprotection, the first official document on photoprotection developed in Brazil for Brazilians, with recommendations on matters involving photoprotection.

Effects of ultraviolet radiation, visible light, and infrared radiation on erythema and pigmentation: a review

The effects of ultraviolet radiation, visible light, and infrared radiation on cutaneous erythema, immediate pigment darkening, persistent pigment darkening, and delayed tanning are affected by a variety of factors. Some of these factors include the depth of cutaneous penetration of the specific wavelength, the individual skin type, and the absorption spectra of the different chromophores in the skin. UVB is an effective spectrum to induce erythema, which is followed by delayed tanning. UVA induces immediate pigment darkening, persistent pigment darkening, and delayed tanning. At high doses, UVA (primarily UVA2) can also induce erythema in individuals with skin types I-II. Visible light has been shown to induce erythema and a tanning response in dark skin, but not in fair skinned individuals. Infrared radiation produces erythema, which is probably a thermal effect. In this article we reviewed the available literature on the effects of ultraviolet radiation, visible light, and infrared radiation on the skin in regards to erythema and pigmentation. Much remains to be learned on the cutaneous effects of visible light and infrared radiation.

Relationship between skin parameters (darkness or thickness) and photoreaction of Chinese Han skin

BACKGROUND

Skin pigmentation and the stratum corneum are the two primary natural factors that protect against UV damage. Although several classification systems exist to quantify the ability of the skin to protect itself from damaging UV radiation, few reports have assessed skin parameters and photoreaction in persons of Han Chinese descent.

AIMS

To understand the relationship between skin darkness, skin thickness, and photoreaction in Chinese Han subjects.

METHODS

Thirty-one subjects were exposed to UVA and UVB. Minimal persistent pigment darkening dose (MPPD) and minimal erythema dose (MED) were obtained. Before the UV irradiation, the test sites were measured by the Mexameter MX 16, Chromameter CR400, and Skin B-ultrasonic to determine skin color and thickness>. Using the ratio of J(MPPD)/J(MED), we classified the subjects into four energy skin phototypes (ESPTs) and the skin parameters for each of these groups were analyzed.

RESULTS

Skin color and skin thickness were significantly different among the ESPTs. There was also a significant positive correlation between skin group and the skin color and thickness parameters (b*, melanin index [MI], thickness). As the ESPTs increased from ESPT A to ESPT D, the mean dose to achieve MED increased, while the MPPD decreased.

CONCLUSION

As the ESPTs increased from type A to type D, there was a proclivity to tan rather than burn. Similarly, the skin became darker and thicker as the phototype increased from A to D.

Gender differences in UV-induced inflammation and immunosuppression in mice reveal male unresponsiveness to UVA radiation

Immunosuppression attributed mainly to the UVB (290-320 nm) waveband is a prerequisite for skin cancer development in mice and humans. The contribution of UVA (320-400 nm) is controversial, but in mice UVA irradiation has been found to antagonise immunosuppression by UVB. In other studies of photoimmune regulation, protection mediated via oestrogen receptor-β signalling was identified as a normal endogenous defence in mice, and was shown to depend on UVA irradiation. A gender bias in photoimmune responsiveness was thus suggested, and is tested in this study by comparing the UV-induced inflammatory and immune responses in male and female hairless mice. We report that male mice, which show greater skin thickness than females, developed a less intense but slower resolving sunburn inflammatory oedema, correlated with reduced epidermal expression of pro-inflammatory IL-6 than females following solar simulated UV (SSUV, 290-400 nm) exposure. On the other hand, the contact hypersensitivity reaction (CHS) was more severely suppressed by SSUV in males, correlated with increased epidermal expression of immunosuppressive IL-10. Exposure to the UVB waveband alone, or to cis-urocanic acid, suppressed CHS equally in males and females. However, whereas UVA irradiation induced immunoprotection against either UVB or cis-urocanic acid in females, this protection was significantly reduced or abrogated in males. The results indicate that males are compromised by a relative unresponsiveness to the photoimmune protective effects of UVA, alone or as a component of SSUV. This could explain the known gender bias in skin cancer development in both mice and humans.

Occupational sunlight exposure and risk of renal cell carcinoma

BACKGROUND

Recent findings indicate that vitamin D obtained from ultraviolet (UV) exposure may reduce the risk of several different cancers. Vitamin D is metabolized to its active form within the kidney, which is the major organ for vitamin D metabolism and activity. Because both the incidence of renal cell carcinoma (RCC) and the prevalence of vitamin D deficiency have increased over the past few decades, in the current study, the authors explored whether occupational UV exposure was associated with RCC risk.

METHODS

A hospital-based, case-control study of 1097 patients with RCC (cases) and 1476 controls was conducted in 4 Central and Eastern European countries. Demographic and occupational information was collected to examine the association between occupational UV exposure and RCC risk.

RESULTS

A significant reduction (24%-38%) in the risk of RCC was observed with increasing occupational UV exposure among men who participated in the study. No association between UV exposure and RCC risk was observed among women who participated. When the analyses were stratified by latitude as another estimate of sunlight intensity, a stronger reduction (71%-73%) in the risk of RCC was observed between UV exposure and cancer risk among men who resided at the highest latitudes.

CONCLUSIONS

The current results suggested that, among men, there is an inverse association between occupational UV exposure and the risk of RCC. Replication studies are warranted to confirm these results.

Neutron activation analysis and X-ray Rayleigh and Raman scattering of hair and nail clippings as noninvasive bioindicators for Cu liver status in Labrador Retrievers

The heritability of chronic hepatitis in the Labrador Retriever is studied with the aim of identifying the related gene mutation. Identification of cases and controls is largely based on instrumental neutron activation analysis (INAA) Cu determination in liver biopsies. The burden for these companion animals may be reduced if nail clippings and hair (fur) could serve as a noninvasive indicator for the hepatic Cu concentrations. No correlation was found between hepatic Cu concentrations and Cu concentrations in hair and nail samples. However, hair and nail samples were also analyzed by X-ray tube excitation, taking advantage of the X-ray Compton, Rayleigh, and Raman scattering which reflects the organic components such as the type of melanin. Principal component analysis provided first indications that some differentiation between healthy and sick dogs could indeed be obtained from hair and nail analysis.

Figure

[Behaviors related to sunlight exposure versus protection in a random population sample from 15 Brazilian State capitals and the Federal District, 2002-2003]

This article examines region-specific relations between prevalence of protection against sunlight and socio-demographic and behavioral variables in Brazil. Data were derived from a cross-sectional population-based random sample. Information on sunlight exposure was available for a total of 16,999 individuals 15 years and older. Comparing the North and South of Brazil, crude differences between women and men in the use of "sunscreen" and "protective headwear" were +10.9% (95%CI: 7.1; 14.6) and -11.6% (95%CI: -17.0; -6.3) in the North and +21.3% (95%CI: 17.7; 24.9) and -16.0% (95%CI: -20.2; -12.5) in the South. Adjusted differences by selected variables confirmed that women use more sunscreen protection and less headwear protection as compared to men in both the North and South, but the difference was not homogeneous by region (interaction term p value < 0.05).

Grading of Iris Color with an Extended Photographic Reference Set

Purpose

To present a new iris pigmentation classification system based on comparison of iris pigmentation to a set of 24 standard eye photographs, with the aim of gaining on accuracy and on applicability for retinal straylight studies.

Methods

A reference set of 24 eye photographs was established by ranking the photographs from least (number 1) to most (number 24) iris pigmentation. Reproducibility was tested by grading a sample of 67 eye photographs with this reference set.

Results

The overall variation between observers was 1.46 on a scale of 0 to 25.

Conclusion

The new method is promising to be more accurate than existing iris color classification systems in clinical situations where objective colorimetry-based systems are not available. The method may be useful to assess iris translucency and fundus reflectance as sources of variation in retinal straylight.

Studies of associations between disability in multiple sclerosis, skin type, gender and ultraviolet radiation

Recent studies suggest ultraviolet radiation (UVR)/vitamin D is protective against the development of multiple sclerosis (MS). We determined if outcome in MS is associated with the surrogate for host pigmentation, skin type, and parameters of UVR exposure. We used a validated questionnaire to determine skin type and UVR exposure during childhood (0-16 years), and early adult life (17-40 years), in 448 Caucasians with MS. Outcome was assessed using the Kurtzke Expanded Disability Status Score (EDSS) and Multiple Sclerosis Severity Scale (MSSS). We studied the association of skin type and exposure with dichotomized values of EDSS (< and ≥6) and MSSS (continuous variable) using logistic and linear regression analyses, respectively. Sex, onset age and MS duration were significantly associated with outcome in all patients. In 169 females with established disease (≥10 years), sun sensitive skin types 1 and 2 were associated with reduced risk of EDSS ≥6 (odds ratio =0.50; 95% CI = 0.26-0.97), and higher MSSS values (coefficient = -0.86; 95% CI = -1.67 to -0.05). Parameters of UVR exposure were not significantly associated with outcome. These preliminary data show an association between skin type and disability in female MS patients. They are compatible with independent studies suggesting that exposure mediates MS pathogenesis via vitamin D. Further studies are required to properly assess these potentially important findings. Multiple Sclerosis 2007; 13: 369-375. http://msj.sagepub.com

Preventive effects of phosphorylated ascorbate on ultraviolet-B induced apoptotic cell death and DNA strand cleavage through enrichment of intracellular vitamin C in skin epidermal keratinocytes

Mortality of mouse keratinocytes Pam212 that were irradiated with ultraviolet-B (UVB) was shown to be repressed by pre-irradiated administration with L-ascorbic acid (Asc) or more markedly with Asc-2-O-phosphate (Asc2P), but not with dehydroascorbic acid (DehAsc) or Asc-2-O-alpha-glucoside (Asc2G), although not repressed by post-irradiated administration. The cytoprotection by Asc2P was restricted against UVB below 5-20 mJ/cm2, and exhibited markedly by administration for a period over 2 h, which may be caused by intracellular Asc that was accumulated via dephosphorylation of Asc2P and was increased, 6-24 h after, to levels above twice as abundant as those of Asc-administration. Pre-irradiated Asc2P-administration slightly repressed a DNA ladder-like electrophoretic pattern for UVB-irradiated keratinocytes, containing the histone-bound DNA fragments as shown by ELISA assay, and appreciably repressed the DNA-3'OH cleavage terminals as shown by terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) stain. Thus, prevention of UVB-induced cell death by Asc2P was shown to occur concurrently with inhibition of DNA cleavages and enrichment of intracellular Asc.

Inhibitory effect of piperlonguminine on melanin production in melanoma B16 cell line by downregulation of tyrosinase expression

Tyrosinase is a key enzyme for melanin biosynthesis, and hyperpigmentation disorders are associated with abnormal accumulation of melanin pigments, which can be improved by treatment with depigmenting agents. In the present study, piperlonguminine from Piper longum was discovered to inhibit melanin production in melanoma B16 cells stimulated with alpha-melanocyte stimulating hormone (alpha-MSH), 3-isobutyl-1-methylxanthine or protoporphyrin IX, where the compound exhibited stronger depigmenting efficacy than kojic acid. However, piperlonguminine did not affect 1-oleoyl-2-acetyl-sn-glycerol-induced melanogenesis and did not affect protein kinase C-mediated melanin production. Surprisingly, piperlonguminine did not inhibit the catalytic activity of cell-free tyrosinase from melanoma B16 cells but rather suppressed tyrosinase mRNA expression. This effect was attributed to the inhibitory action of piperlonguminine on alpha-MSH-induced signaling through cAMP to the cAMP responsive element binding protein that in turn regulates the expression of the microphthalmia-associated transcription factor, a key activator of the tyrosinase promoter. This study demonstrates that piperlonguminine is an efficient depigmenting agent with a novel mechanism of action.

Cytogenetic alterations in nonmelanoma skin cancer: a review

Since the advent of cytogenetic analysis, knowledge about fundamental aspects of cancer biology has increased, allowing the processes of cancer development and progression to be more fully understood and appreciated. Classical cytogenetic analysis of solid tumors had been considered difficult, but new advances in culturing techniques and the addition of new cytogenetic technologies have enabled a more comprehensive analysis of chromosomal aberrations associated with solid tumors. Our purpose in this review is to discuss the cytogenetic findings on a number of nonmelanoma skin cancers, including squamous- and basal cell carcinomas, keratoacanthoma, squamous cell carcinoma in situ (Bowen's disease), and solar keratosis. Through classical cytogenetic techniques, as well as fluorescence-based techniques such as fluorescence in situ hybridization and comparative genomic hybridization, numerous chromosomal alterations have been identified. These aberrations may aid in further defining the stages and classifications of nonmelanoma skin cancer and also may implicate chromosomal regions involved in progression and metastatic potential. This information, along with the development of newer technologies (including laser capture microdissection and comparative genomic hybridization arrays) that allow for more refined analysis, will continue to increase our knowledge about the role of chromosomal events at all stages of cancer development and progression and, more specifically, about how they are associated with nonmelanoma skin cancer.

Modulation of light-induced skin tumors by N -acetylcysteine and/or ascorbic acid in hairless mice

The light emitted by halogen quartz bulbs contains a broad spectrum of UV wavelengths, is strongly genotoxic and is a potent inducer of skin tumors in hairless mice. By using a UVC filter, this light mimics solar radiation and induces a variety of genomic and transcriptional alterations in mouse skin. UV-related carcinogenesis involves depletion of antioxidants and glutathione in skin cells. On this basis, we evaluated modulation of carcinogenicity of UVC-filtered halogen lamps in SKH-1 hairless mice by the antioxidants N-acetyl-l-cysteine (NAC) and ascorbic acid (AsA). Both agents were given in the drinking water, either individually or in combination. The earliest skin lesions were detected after 300 days' exposure to light and became confluent in a number of mice after 480 days. NAC administration prolonged the latency time by 90 days. Moreover, NAC considerably and significantly decreased both incidence and multiplicity of light-induced skin tumors, prevented the occurrence of malignant lesions (squamocellular carcinomas) and reduced the tumor size. In contrast, AsA, which may behave as a prooxidant rather than an antioxidant, increased the multiplicity of total skin tumors, carcinomas in situ and squamocellular carcinomas. Co-administration of NAC with AsA significantly attenuated the negative effect of AsA, presumably due to the ability of this thiol to maintain a reduced environment. Therefore, in agreement with our previous in vitro findings, oral NAC is able to attenuate the detrimental effects of AsA.

Decreased carotenoid concentrations due to dietary sucrose polyesters do not affect possible markers of disease risk in humans

Excessive consumption of energy and fat increases the risk for obesity. Snacks containing sucrose polyesters (SPE) as a dietary fat replacer are on the market in the United States. SPE products have been shown to lower concentrations of serum carotenoids in short-term studies. Experimental studies on the longer-term effects on health of decreased carotenoid concentrations are lacking. A 1-y randomized, double-blind, placebo-controlled parallel trial was performed. Subjects (n = 380) with a habitual low or high fruit and vegetable intake were assigned to the treatments (0, 7, 10 or 17 g/d SPE). SPE was given in the form of spreads, chips or both. The groups were compared for serum carotenoids, vitamins and markers of oxidative damage, eye health, cardiovascular health and immune status. After 1 y, serum lipid-adjusted carotenoids showed the largest decrease in the SPE chips and spread group (17 g/d) compared with the control group [alpha-carotene 33%; beta-carotene 31%, lycopene 24%, beta-cryptoxanthin 18%, lutein 18% (all P < 0.001) and zeaxanthin 13% (P < 0.05)]. Consumption of SPE spread (10 g/d SPE) decreased carotenoid concentrations by 11-29% (all P < 0.05). SPE chips (7 g/d SPE) decreased zeaxanthin (11%), beta-carotene (12%) and alpha-carotene (21%; all P < 0.05). Serum lipid adjusted alpha-tocopherol decreased significantly by 6-8% (all P < 0.001) in all SPE groups. No negative effects were observed on markers of oxidation, eye health, cardiovascular health or immune status. This study shows that decreases in serum carotenoid concentrations do not affect possible markers of disease risk.