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PubMed1988

Sunlight, melanogenesis and radicals in the skin.

Melanocytes are cells of neural crest origin residing at the dermal-epidermal juncture. They produce specialized organelles called melanosomes within which the biochemical processes of melanization occurs. UV radiation is capable of inducing melanogenesis and, during the biosynthesis of melanins, several of the putative precursors "leak out" of the melanosome and can be detected in the skin, serum and urine of individuals undergoing active melanogenesis. Most notable are the cysteinyldopas (formed by nucleophilic addition of cysteine to dopaquinone) and several dihydroxyindoles (formed by intramolecular cyclization of dopaquinone). These catechols often are methylated in the melanocyte to afford a mixture of the monomethoxy derivatives and, in some cases, the dimethoxy species. Recent investigations in our laboratories have demonstrated that the cysteinyldopas, dihydroxyindoles, and their various methylated derivatives are photochemically unstable. Irradiation with biologically relevant ultraviolet radiation (i.e. wavelengths greater than 300 nm) results in the rapid destruction of the precursors/metabolites and the production of a variety of free radical species. The photochemistry and potential photobiological significance of melanogenic intermediates is discussed.

Free Radicals↗
PubMed2002

Hypovitaminosis D and hyperparathyroidism in physically inactive elderly Japanese living in nursing homes: relationship with age, sunlight exposure and activities of daily living.

BACKGROUND AND AIMS: The purposes of this study were to investigate the prevalences of hypovitaminosis D and hyperparathyroidism in physically inactive elderly people living in Japanese nursing homes and determine any correlations with demographic, environmental and/or life-style factors. METHODS: We targeted 220 elderly people living in nursing homes for the physically disabled in Japan. Of these, 133 (women, 113; men, 20) subjects who agreed and met our inclusion criteria were studied. The average age of the subjects was 84.6 years (SD 8.2). Serum 25-hydroxyvitamin D3 (25[OH]D3), intact parathyroid hormone (intact PTH), creatinine, and albumin concentrations were measured in each subject. Total hours of sunshine during the previous 5 weeks, activities of daily living (ADL) levels, and dietary vitamin D intake were also measured. ADL levels were evaluated using the Physical Self-Maintenance Scale (5-point scale). The examinations were performed between October and December, 1999. RESULTS: The average concentrations of serum 25(OH)D3 and intact PTH were 29.9 nmol/L (SD 13.1) and 5.04 pmol/L (SD 2.27), respectively. The prevalences of hypovitaminosis D (25[OH]D3<30 nmol/L) and hyperparathyroidism (intact PTH>6.90 pmol/L) were 77/133 (57.9%) and 21/133 (15.8%), respectively. Serum 25(OH)D3 concentrations were positively associated with hours of sunshine (R2=0.371, p<0.001) and serum albumin concentrations (R2=0.086, p<0.001), but not with age (p=0.075) or total ADL score (p=0.527). A negative association between serum intact PTH and 25(OH)D3 levels was found in subjects who were 80 years or older (p<0.001) but not in subjects under the age of 80 years. CONCLUSIONS: Hypovitaminosis D and hyperparathyroidism are commonly seen in elderly Japanese with low ADL levels. Hypovitaminosis D seems to adversely affect PTH levels, especially in the very elderly.

Activities of Daily Living↗
PubMed2005

[Sunlight-induced granulomatous reaction to permanent lip liner].

The demand for permanent make up and especially permanent lip liner has increased in recent years in Germany. Information about complications is not available in the medical literature, because tattooing is a trade whose results and problems are not monitored and documented, as is the case for medical procedures. A female patient with permanent lip liner experienced no complications for one year. Then, after intensive sun exposure she developed solid, linear papules along the outer margin of her lips. Histology revealed a granulomatous tissue reaction with a marked lymphohistiocytic infiltrate including epithelioid histiocytes. Treatment with topical steroids over three weeks led to a complete healing without relapse. To the best of our knowledge this is the first report on UV-light-induced granulomatous reaction to permanent lip liner.

Female↗
PubMed1999

Decreased serum levels of 1,25-(OH)2 vitamin D during 1 year of sunlight deprivation in the Antarctic.

French Antarctic territories harbor bases that are devoted to scientific and technical work. Living and working conditions during 1-year sojourns in such an environment are quite acceptable, but the confinement and the drop in ultraviolet B radiation exposure during winter months raise the problem of preservation of normal vitamin D status. Seasonal variations in 25-hydroxyvitamin D [25(OH)D] levels have been well documented, but the effect of sunshine deprivation on 1,25 dihydroxyvitamin D [1,25(OH)2D] levels is quite controversial. The aim of this study was to address this question under the exceptional conditions of lack of sunshine exposure. Fifteen male Caucasian subjects participating in a 1-year mission in Antarctica were investigated. They were subjected to seven blood samplings, one before and six during their sojourn. Serum levels of 25(OH)D, 1,25(OH)2D, osteocalcin, and ICTP were measured. We found that levels of 25(OH)D and 1,25(OH)2D significantly decreased in these subjects during the mission, minimum levels being observed 10 months after their departure from France. ICTP concentrations did not change throughout this study, but osteocalcin levels were found to be higher at the end of the sojourn than before departure, which could argue for the existence of bone remodeling changes. Further studies are now needed to fully investigate bone metabolism changes and to address the question of vitamin D supplementation during this kind of sojourn.

Adult↗
PubMed2006

UV, latitude, and spatial trends in prostate cancer mortality: all sunlight is not the same (United States).

OBJECTIVE: We showed previously that Caucasian mortality rates from prostate cancer for 1970-1979 are significantly inversely correlated with ultraviolet (UV) radiation. We now present the analysis of prostate cancer mortality data over a 45-year period (1950-1994) in order to examine the persistence of this pattern. Furthermore, because vitamin D synthesis does not occur during winter months at latitudes higher than 40 degrees N, we examined this relationship above and below 40 degrees N latitude. METHODS: We used trend surface and linear regression analyses to characterize the relationship between prostate cancer mortality and UV radiation for U.S. counties at northern and southern latitudes. RESULTS: For U.S. Caucasians, prostate cancer mortality rates at the county and SEA levels followed a significant north-south spatial trend that is the inverse of UV radiation. We found significant inverse correlations between UV radiation and prostate cancer mortality at all time points over this 45-year period. These correlations were significantly more pronounced at locations north of 40 degrees N latitude. CONCLUSIONS: Our analyses confirm and extend our findings that the geographic distribution of prostate cancer mortality is the inverse of that of UV radiation. This effect is strongest in counties north of 40 degrees N latitude, where vitamin D synthesis is limited to non-winter months. These findings add additional support for the hypothesis that vitamin D insufficiency increases risk for prostate cancer.

Humans↗