摘要:

AbstractThe present study was carried out to examine the role of reactive oxygen species in mediating the melanogenic effects of UVR. B16 mouse melanoma cells responded to a single dose of UVR by showing increases in their melanin content. Although there was a small increase in melanin at 48‐72 hours, which was associated with a rise in tyrosinase activity at 48 h, the greatest change occurred at 3 h and this was not associated with an increase in tyrosinase activity. This short‐term response, unlike the more delayed melanogenic response, was reduced by superoxide dismut‐ase (SOD). Xanthine oxidase (XO), which generates the superoxide anion (O2). also increased the melanin content of B16 melanoma cells with effects at 3 h and 48 h. As with UVR, the delayed response was accompanied by an increase in tyrosinase activity but no such association was evident at 3 h. In addition, the short‐term effect, like that seen with UVR, was reduced with SOD and to a lesser extent with catalase. In contrast to the effects found with XO, glucose oxidase, which generates hydrogen peroxide, had no effect on the melanin content or tyrosinase activity of the B16 cells. These results confirm previous observations that UVR is able to act directly on cells to bring about delayed increases in melanogenesis. They further demonstrate that UVR also stimulates melanogenesis through a more rapid action that is not associated with an activation of tyrosinase. This effect could be mediated by the O2which, rather than activating tyrosinase, could act by serving as a substrate for the

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1994.tb00266.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIt has been postulated that patients withMalassezia furfurassociated dermatoses have a deficient cell‐mediated immune response toM. furfur. This study examined the cell‐mediated immune responses toM. furfurserovars A, B and C of 10 patients with pityriasis versicolor and 10 age‐ and sex‐matched controls; and 10 patients with seborrheic dermatitis and 10 age‐ and sex‐matched controls. The responses to each serovar ofM. furfurwere assessed using the lymphocyte transformation assay and the leukocyte migration inhibition assay. The lymphocyte transformation responses of the patients with pityriasis versicolor toM. furfurserovars A, B and C (O/10, 6/10 and 5/10 respectively) were not significantly different from those of controls (0/10, 2/10 and 1/10). However, for patients with seborrheic dermatitis, significantly more patients lymphocytes responded to serovars B and C (6/10 and 6/10 respectively) than those of controls (1/10 and 1/10). No patient or control responded to serovar A. In the leukocyte migration inhibition assay, the leukocytes from a greater proportion of patients with pityriasis versicolor (5/7) responded to serovar B than controls (2/10); and the leukocytes from a greater proportion of patients with seborrheic dermatitis (4/10) responded to serovar C than controls (0/9). Thus, this data did not indicate the presence of any cell‐mediated immune deficiency toM. furfurin patients with pityriasis versicolor or seborrheic dermatitis, as measured by the lymphocyte transformation assay or the leukocyte migration inhibition assay. The greater responsiveness of T lymphocytes from patients may indicate that T lymphocytes might be involved in the pathogenesis of t

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1994.tb00267.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIn inflammatory dermatoses. activated T cells produce inter‐feron‐gamma (IFN‐γ), which interacts with keratinocytes and contributes to the direct activation of these cells by inducing, among other factors, the expression of HLA‐DR antigens and intercellular adhesion molecule‐1. However, the action of IFN‐γ on epidermal cell cytokine production is not known. Our aim was to assess the effect of IFN‐γ on the production of IL‐1 by normal human keratinocytes cultured in low calcium medium (MCDB153). In comparison with controls, the addition of nontoxic IFN‐yγ concentrations (50‐500 U/ml) to cell cultures induced a significant increase of IL‐1α and IL‐1β production predominantly after 100 U/ml treatment in the cell extracts as well as in the supernatants at 24h and 48h. The production of the antagonist. IL‐1RA, was also enhanced and the effect of the critical concentration (100 U/ml) was more evident. However, the absence of a characteristic dose response could not be explained by an antiproliferative effect of high IFN‐γ concentrations (250 and 500 U/ml) on cultured keratinocytes or by the induction of the nuclear stress protein, Hsp72. two phenomena known to down‐regulate IL‐1 biosynthesis. In conclusion, the modifications in keratinocyte IL‐1 production under IFN‐γ stimulation can contribute to activate the epidermal cells and thu

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1994.tb00268.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1994.tb00269.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1994.tb00270.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY