摘要:

SummaryTyrosinase is considered to be the rate‐limiting enzyme for the biosynthesis of melanin in epidermal melanocytes. and thus tyrosinase activity is thought to be a major regulatory step in melanogenesis. To determine whether the rate of pigment production was controlled at the level of tyrosinase gene expression. we developed a culture system capable of generating large populations of pure human melanocytes and then measured both melanin content as determined spectrophotometrically by absorption at 475 nm and mRNA levels as detected by hybridization with cloned cDNA level 34, encoding human tyrosinase. We examined the relationship between pigment content and tyrosinase mRNA levels among human melanoma and melanocyte lines with very different levels of basal pigmentation: between two clones of a single human melanoma line, one pigmented and one amelanotic, and sequentially in melanocytes before and after simulation with isoburylmethylxanthine to increase melanin content per cell. Using Northern blot analysis andin‐situhybridization we found no correlation between tyrosinase message levels and melanin content, suggesting that post‐transcriptional regulation of tyrosinase and/or other events determine the rate of pigment synthesis in human melano

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14161.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryAndrogen metabolism was investigated in normal human apocrine glands and in those isolated from age‐matched patients with hidradenitis suppurativa. Axillary glands were isolated by shearing and androgen interconverting enzyme activities were measured in cell‐free homogenates by incubation with [3H] dehydroepiandrosterone, [3H] androstenedione and [3H] testosterone. The activities (pmol/ mg protein/min: mean + SEM) of 3 β‐hydroxysteroid dehydrogenase δ4–5‐isomerase (10·0 ± 1·2 vs. 5·3±0.5:n= 5) and 17 β‐hydroxysteroid dehydrogenase (58·l±4·5 vs. 35·7±5·2:n= 5) were significantly lower (P<0–005) in hidradenitis suppurativa, whereas 5 α‐reductase activity (12·5±2·3 vs. 12·5±2·0:n= 5) was similar. This report suggests that hidradenitis suppurativa cannot be attributed to exaggerated activities of end‐

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14162.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThe effect of cyclosporin A (CyA) on the capacity of human epidermal Langerhans cells (LC) to stimulate allogeneic T cells or to present antigen to autologous T cells was investigated. Preparations of LC enriched by discontinuous density gradient centrifugation were pulsed for 2 or 16 h with graded doses (5–5000 ng/ml) of CyA prior to co‐culture with T cells. Pretreatment of LC with CyA resulted in a dose‐dependent decrease of the functional capacity of LC to stimulate T cells. This inhibition (up to 90%). already achieved after a pulse of 2 h, was not due to a cytotoxie effect of the drug and appeared to be reversible. The possibility that CyA exerted its effect indirectly on T cells via release of CyA from LC into the supernatant during co‐culture was excluded. The suppression of immunostimulatory function was a direct effect of the drug on LC. CyA did not affect the production by LC of IL‐1 or prostaglandin nor the expression of MHC class II products HLA‐D and RFDl or adhesion molecules ICAM‐1 and LFA‐3. These results suggest that inhibition of contact allergic skin reactions by CyA may be due in part to an impairment of the

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14163.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryUsing a direct immunogold technique, we studied the level of immunological events in the skin basement membrane in a patient with herpes gestationis during blister formation. Within the lamina lucida. IgG and C3 were localized bencath the basement membrane of basal keratinocytes, 30–40 nm above the lamina densa. In many areas of blister formation sub‐basal dense plates. but probably also the upper parts of the hemidesmosomes were separated from the roof of the blister. In the perilesional lamina lucida and in the blister. lgG and C3 containing amorphous grains. Most probably immunocomplex aggregates, were detected. They covered the basement membrane of keratinocytes and left free a 30–40 nm band above the lamina densa. Our study indicates that in herpes gestationis the cleavage, accompanied by IgG, C3 and immunocomplex deposition, occurs at the level of the subbasal dense plate, However, cleavage through upper hemidesmosomal structures can occur in parallel. These data further support the involvement of hemidesmosmes in the pathogenesis of the disease and therefore in its relationship to bullous pemph

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14164.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryA model of skin inflammation induced by reactive oxygen species has been established using the hydrogen‐peroxide‐producing enzyme glucose oxidase. As a means of increasing the half‐life of the enzyme and tissue retention polyethylene glycol (PEG) was attached. A rapid inflammatory response occurred consisting of an oedematous. non‐erythemic swelling lasting at least 48 h. Histologically. there was an infiltration of the dermis by monocytes and neutrophils. collagen matrix breakdown and damage to the vascular endothelium. This response was significantly inhibited by both catalase and superoxide dismutase attached to PEG (PEG‐CAT and PEG‐SOD, respectively). PEG alone produced no effects. PEG‐CAT was able to sustain an inhibitory effect for at least 12 h. whereas PHG‐SOD significantly reduced inflammation for up to 6 h. PEG‐SOD may have an exacerbatory effect ov

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14165.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThe intensity of the cutaneous response was assessed after application of a standard irritant to increasing areas of normal forearn skin. Twenty subjects were tested to determine the minimal irritant does (MID) to dilutions of aqueous sodium dodecyl sulphate. Each subject was then treated under occlusion for a period of 24 hours with different areas of filter paper (9.25,100, 225 and 400 mm2) soaked with the concentration required to give the individual's MID. At 25 and 48 hours the degree of erythema was assessed using a 0–4 arbitrary scale, a 10‐cm visual analogue scale (VAS) and an erythema meter. Cutaneous blood flow was measured with a laser‐Doppler device and cutaneous oedema measured by pulsed A‐scan ultrasound. The results at 25and 48hours were almost identical. Both forms of visual assessment (arbitrary scale and VAS) showed an increase in perceived erythema with increasing area and this was confirmed by the erythema meter. Further area‐related changes were noted with both cutaneous blood flow and ultrasound mea

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14166.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThe pattern of binding of two different types of IgA class pemphigus‐like antibodies was compared with that of the true IgG class pemphigus antibody. The IgG antibodies from pemphigus vulgaris (PV) and pemphigus foliaceus (PF) sera bound to the intercellular spaces in normal human epidermis, whereas only the PV antibody reacted with monolayers of keratinocytes derived from human foreskin. Both IgG and IgA antibodies from a patient with PF were found in the intercellular spaces of the epidermis and only the IgA antibody reacted with the cultured keratinocytes. The IgA antibody from a patient with a vesiculopustular eruption and whose serum contained IgA intercellular space antibody alone, bound to the upper epidermis but not to the monolayers of keratinocytes. These findings indicate that PV but not PF antigens can be expressed by monolayers of cultured human keratinocytes and that there are at least two distinct types of IgA intercellular antibodie

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14167.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryOne‐hundred and eight patients with psoriasis completed a questionnaire concerning their knowledge about the condition. This was carried out at two departments of dermatology, at Bridgend General Hospital and Leeds General Infirmary. There were no significant differences between the two centres, and the main source of the patients’information about psoriasis was from a dermatologist, hut several other sources such as newsletters were of h

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14168.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryA retrospective questionnaire was conducted as to the risk factors for facial skin cancer with emphasis on acne and past treatments for acne, in particular use of benzoyl peroxide preparations. The response rate was 90·9% for 964 cases and 79·9% for 3856 controls. There was no association between acne and the use of any acne medication for the risk of facial skin cancer. Cases of skin cancer were significantly more likely to have used phototherapy or sunbeds than the controls (P= 0·024), and more likely to have had radiotherapy prior to diagnosis (P= 0·001). The major risk factors as determined by generalized linear interactive modelling were family history of skin cancer (odds ratio 2·68; 95% confidence interval 2·15, 3·34), light skin (1·54; 1·25, 1·89), sunburning easily (1·43; 1·16, 1·76) and Irish, Scottish, Scandinavian or German mothers (1·33

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14169.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummarySix‐hundred and fifteen young healthy Italian males were examined for the number, localization and clinical features of melanocytic naevi. The data were correlated with the phenotype and skin type of the subjects. Eighty‐ eight per cent had melanocytic naevi, 7% congenital naevi and 21.3% atypical naevi with a diameter>5mm and indistinct or irregular borders and were variable in colour. Of the sample only 2.43% had more than 30 naevi. Those subjects with blond or red hair, fair skin, blue or green eyes and with a skin type of I and II had higher numbers of naevi which were more often atypical than those subjects with dark hair, brown eyes and who were skin types II

ISSN:0007-0963    

DOI:10.1111/j.1365-2133.1991.tb14170.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY