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Black Skin (black + skin)
Selected AbstractsBlushing in black skinJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2003F I D Konotey-Ahulu [source] Melanin Offers Protection Against Induction of Cyclobutane Pyrimidine Dimers and 6,4 Photoproducts by UVB in Cultured Human Melanocytes,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2001Nico P. M. Smit ABSTRACT The goal of this investigation was to correlate the melanin content in human pigmentary cells with the generation of UVB-induced photoproducts and to examine the relationship between the melanin content and the removal of the photoproducts. Cultured melanocytes from light-skinned individuals synthesized less melanin and produced more cyclobutane pyrimidine dimers and 6,4 photoproducts upon UVB exposure than did melanocytes from black skin. Tyrosine-stimulated melanogenesis provided protection against DNA damage in both cell types. In another set of pigmented cell lines a ratio between eumelanin and pheomelanin was determined. The assessment of association between DNA damage induction and the quantity and quality of melanin revealed that eumelanin concentration correlated better with DNA protection than pheomelanin. Skin type,I and skin type,VI melanocytes, congenital nevus (CN)-derived cells and skin type,II melanocytes from a multiple-melanoma patient were grown in media with low or high l -tyrosine concentration. The cells were irradiated with 200 J/m2 UVB, and the levels of the photoproducts were determined immediately and after 6 and 24 h. Once again the induction of the photoproducts was mitigated by increased melanogenesis, and it was inversely correlated with the skin type. No significant differences were found for the removal of photoproducts in the cultures of skin types I and VI and CN cells. No indications of a delay in the removal of photoproducts in the melanocytes from the multiple-melanoma patient were found either. [source] Depigmenting Action of Phenylhydroquinone, an o -Phenylphenol Metabolite, on the Skin of JY-4 Black Guinea-PigsPIGMENT CELL & MELANOMA RESEARCH, Issue 6 2002Kuniaki Tayama The effects of o -phenylphenol (OPP) and its metabolite, phenylhydroquinone (PHQ) on the skin of JY-4 black guinea-pigs were studied. Topical application of 1 or 5% PHQ on the black skin of the back caused marked depigmentation and hypopigmentation of the skin after 5 weeks, whereas OPP applied at the same concentrations had little effect. Depigmented skin had an increased L* (lightness) value in the CIE-L*a*b* color system. This corresponded with a decreased number of melanocytes and melanosomes in the melanocytes and keratinocytes, the disruption of melanosomes in the melanocytes, and destruction of the membranous organelles of the melanocytes. These morphological and numerical changes in epidermal melanocytes indicate that selective melanocyte toxicity occurred. Furthermore, application of PHQ to the skin of white guinea-pigs caused skin irritation, as shown by a colorimetric increase in a* value (redness) and by histological observation of inflammation. This study confirmed that OPP, which is a reported depigmenter, has little depigmenting action, while its metabolite, PHQ, is a potent depigmenter preferentially affecting melanocytes. [source] The Impact of Preexisting or Acquired Kaposi Sarcoma Herpesvirus Infection in Kidney Transplant Recipients on Morbidity and SurvivalAMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2009C. Francès The impact of preexisting or acquired Kaposi sarcoma herpesvirus (KSHV) infection in kidney transplant recipients was evaluated in a prospective study. Serum collected from kidney donors and recipients before transplantation were tested for antibodies against KSHV latent nuclear antigen. Three groups of recipients were defined: group A (KSHV+), group B (KSHV,, KSHV+ donor) and group C (donor and recipient KSHV,). Blood was collected from recipients, every 3 months for 3 years, for KSHV viremia (groups A and B), quantitative (group A) and qualitative serology (group B). Data of group C recipients were extracted from a French database. The prevalence of KSHV antibodies was 1.1% in donors and 3.2% in recipients. There were respectively 161, 64 and 4744 recipients in groups A, B and C. In group A, 13% developed Kaposi's sarcoma (KS). Age >53.5 years (p = 0.025) and black skin (p = 0.0054) were associated with KS development. In group B, three recipients developed clinical manifestations related to KSHV infection. There was no difference in terms of survival and graft loss between the three groups. In conclusion, although kidney recipients should be aware of the additional risk of KSHV morbidity, KSHV+ recipients should not be systematically excluded from kidney transplantation. [source] Reliance on erythema scores may mask severe atopic dermatitis in black children compared with their white counterpartsBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2002M.A. Ben-Gashir SummaryBackground The prevalence of atopic dermatitis (AD) has been shown to be higher in London-born black Caribbean children than in their white counterparts, but little is known about the severity of the disease. Objectives To carry out a longitudinal survey to investigate potential risk factors for AD severity in children. We report our findings in relation to differences in disease severity between white and black children and the effect of inclusion and exclusion of erythema scores on this comparison. Methods The recruited children were identified by their general practitioners (GPs) as having presented with AD, and the U.K. diagnostic criteria for AD were used to verify the diagnosis. Interview and clinical examination of children took place up to four times, 6 months apart. Each time, the same observer assessed AD severity using the SCORAD (SCORe Atopic Dermatitis) index. Potential risk factors and confounders were evaluated with a five-page questionnaire. Non-parametric tests were used for statistical analysis and the study participant remained the unit of the analysis. Results In total, 137 children (82 urban and 55 rural) were recruited, and each seen up to four times. This gave 380 observations (69% of an expected 548). The urban population contained 42 (51%) white children, 26 (32%) black children and 14 (17%) from other races. The rural population was entirely white. The 14 children from other races were completely excluded from the statistical analysis. The black children were all born in the U.K. On crude analysis, children with black skin showed a non-significantly lower risk of severe disease when compared with white children (odds ratio, OR 0·84; 95% confidence interval, CI 0·4,1·76; P = 0·65), while a highly significantly increased risk was found after adjusting for erythema score (OR 5·93; 95% CI 1·94,18·12; P = 0·002). The difference remained significant even after controlling for other potential confounders. Conclusions Black children with AD are about six times more at risk of having severe AD than their white counterparts. GPs and dermatologists should note that erythema can be a misleading indicator of severity in black children. Difficulties of assessment due to skin pigmentation might mean that severe cases are not being detected and appropriately treated. [source] | |||||||||||||