British Journal of Dermatology

WELLER, R.

doi: 10.1046/j.1365-2133.1997.19332063.xpmid: N/A

SummaryNitric oxide (NO) is synthesized by many cells in the body. Low concentrations of NO have homeostatic roles in the circulation and nervous system, whereas high concentrations are biocidal, cytocidal and have immunomodulatory roles. The place of NO in the skin has recently become the focus of much attention, and this review highlights studies on the part played by NO in health and disease.

CURCÓ, N.; SERVITJE, O.; LLUCIA, M.; BERTRAN, J.; LIMÓN, A.; CARMONA, M.; ROMAGOSA, V.; PEYRÍ, J.

doi: 10.1046/j.1365-2133.1997.19342049.xpmid: N/A

SummaryThe diagnosis of early cutaneous T‐cell lymphoma (CTCL) is a difficult point in dermatology. Recently, Southern blot analysis (SBA) and polymerase chain reaction (PCR) have been used to detect clonality in initial lesions in which clinical and histological findings are unspecific. Forty‐one, samples from 25 patients with CTCL were investigated for the presence of T‐cell receptor‐γ gene rearrangement using a nested PCR technique and analysed by polyacrylamide gel electrophoresis (PAGE). Conventional SBA was also performed on 28 samples from 20 of these patients. In addition, 20 samples corresponding to patients with large plaque parapsoriasis (LPP), cutaneous B‐cell lymphoma (CBCL) and eczema were analysed by PCR in the same way as were the CTCL specimens. Most of the CTCL specimens (81%) showed clonality on PCR analysis. Among patients with mycosis fungoides, 71% of initial patch lesions and 100% of plaques and tumours showed clonal disease. Clonality could be detected in three of four histologically negative post‐treatment lesions. Clonal rearrangement was detected in one of three patients with LPP and in three of 10 patients with CBCL. None of the samples corresponding to patients with eczema showed positive results. SBA was significantly less sensitive than PCR in detecting clonality in CTCL patients (42% among early disease and 60% among advanced cases). The results indicate that this PCR/PAGE technique is a reliable and useful method for the detection of clonality in early skin lesions of CTCL patients and probably in the identification of silent extracutaneous involvement.

HERBST, H.; SANDER, C.; TRONNIEK, M.; KUTZNER, H.; HÜGEL, H.; KAUDEWITZ, P.

doi: 10.1046/j.1365-2133.1997.19352050.xpmid: N/A

SummaryThe prevalence of the t(2:5)(p23;q35) and/or anaplastic lymphoma kinase (ALK) gene products in cutaneous anaplastic large cell (ALC) lymphomas and a potential precursor lesion, lymphomatoid papulosis (LyP). is controversial. ALK gene products, which are absent from normal lymphohae‐matopoietic cells, are a phenotypic marker of lymphomas carrying the t(2:5). We used in situ hybridization and immunohistology to screen 14 cutaneous ALC lymphomas, 21 cases of LyP, and one nodal ALC lymphoma associated with LyP for ALK gene products. ALK gene products were not detectable in these cases. In contrast, ALK gene products were found in a lymphonodal ALC lymphoma with subsequent extension to the skin and in t(2:5)‐positive cell lines. Detection of the Epstein‐Barr virus (EBV)‐encoded small nuclear transcripts (EBER), and of immunoglobulin light chain transcripts served to check for the presence of cellular RNA in the tissue sections. EBER transcripts were found in scattered reactive lymphoid cells, but not in atypical or tumour cells. ALK gene expression and EBV infection seem to be a rare finding in cutaneous ALC lymphomas and LyP. This points to a molecular aetiology of primary cutaneous ALC lymphomas and LyP distinct from that of extracutaneous CD30+ lymphoproliferative disease. Detection of the t(2;5) or ALK gene products in cutaneous lymphoproliferative lesions therefore requires exclusion of extracutaneous ALC lymphoma in such patients.

WOOLLONS, A.; CLINGEN, P.H.; PRICE, M.L.; FARLETT, C.; GREEN, M.H.L.

doi: 10.1046/j.1365-2133.1997.19362051.xpmid: N/A

SummaryThere is increasing concern about the adverse health effects associated with the use of sunbeds, particularly with respect to skin photocarcinogenesis. The induction of mutagenic DNA damage is a prerequisite for the development of skin tumours, and it is well established that direct types of damage such as cyclobutane pyrimidine dimers (CPDs) give rise to mutations in tumour suppressor genes and oncogenes. In addition, ultraviolet radiation may induce indirect types of DNA damage, including oxidative products, which are also potentially mutagenic. By using specific DNA repair enzymes (T4 endonuclease V and endonuclease III) and the comet assay we have been able to detect the induction of CPDs, oxidized or hydrated pyrimidine bases and single‐strand breaks in cultured human fibroblasts (MRC‐5) alter exposure for between 15s and 20 min on two different commercial sunbeds containing Philips ‘Performance’ 100W‐R or Philips TL80W/10R lamps. The ratio of endonuclease III to T4 endonuclease V sensitive sites varied substantially between the two lamps and was 3.3% and 18%, respectively. The sunbed containing the ‘Performence’ 100W‐R lamps was as potent at inducing CPDs as was natural sunlight in fine weather. These results establish that commercial tanning lamps produce the types of DNA damage associated with photocarcinogenesis in human cells, and complement epidemiological evidence Indicating the potential risk of using sunbeds.

MITSUI, S.; OHUCHI, A.; HOTTA, M.; TSUBOI, R.; OGAWA, H.

doi: 10.1046/j.1365-2133.1997.19372052.xpmid: N/A

SummaryThe mRNA expressions of various growth regulatory molecules in single human anagen hair follicles were analysed by reverse transcription and polymerase chain reaction. Approximately 370 hair follicles were isolated from 20 normal individuals, and 0.90 ± 0.34 μg (mean ± SD) total RNA was extracted per whole hair follicle. The mRNAs of fibroblast growth factor (FGF)‐l, FGF‐2, FGl‐5. FGF‐7, transforming growth factor (TGF)‐α. TGF‐β1. hepatocyte growth factor, insulin‐like growth factor (IGF)‐I. tumour suppressor gene p53 and high sulphur protein were detected in most or all of the examined hair follicles per target gene. In contrast, none of the mRNAs of FGF‐3, FGF‐4, FGF‐6, FGF‐9 and IGF‐II was detected, and those of TGF‐β2 and TGF‐β3 were detected in only a limited number of the examined hair follicles. Among cyclin‐dependent kinase inhibitors, the mRNAs of p2lwaf1/cip1 and p27kipl were expressed in almost all the hair follicles, while those of p15INK4B and p161NK4A were not detected. These results suggest that both positive and negative factors for the proliferation and differentiation of follicular epithelial cells coexist in a human anagen hair follicle.

DE BROUWER, B.; TÉTELIN, C.; LEROY, T.; BONFILS, A.; VAN NESTE, D.

doi: 10.1046/j.1365-2133.1997.19382053.xpmid: N/A

SummaryHuman hair growth can be monitored for several months after the transplantation of scalp samples from men with androgen‐dependent alopecia on to female nude mice. Hair production from balding sites has been shown to be inhibited in testosterone‐conditioned nude mice. We used this recently reported model to study the effect of a new non‐steroidal antiandrogen – RU 58841 – on human hair growth. Twenty productive scalp grafts from balding men were maintained for 8 months after grafting on to nude mice, and hair production was monitored monthly for 6 months. All mice were conditioned by the topical application of testosterone (testosterone propionate. 300 μg in 10μL; 5 days/week) on the non‐grafted flank. The scalp samples were divided equally according to the estimated hair production potential, which was based on the amount of hair present on the scalp samples before grafting. Each of the two equal groups of grafts was further allocated at random to be treated topically (5 days/week) with blinded solutions of either RU 58841 1% in ethanol, or ethanol as a control.Twenty‐eight active follicles appeared on the 10 control grafts. Among them only two follicles (7%) initiated a second hair cycle. However, the 10 RU58841‐treated grafts bore a total of 29 active follicles, and eight of them (28%) showed a second cycle. The values for the linear hair growth rates (LHGR) were significantly (P<0.04) higher in the RU58841‐treated group. Recycling and increased LHGR indicate a positive action for RU58841 on human hair growth from balding samples grafted on to testosterone‐conditioned nude mice, and encourage a clinical trial to evaluate its potential in the treatment of androgen‐dependent alopecia.

TOMKOVÁ, H.; FUJIMOTO, W.; ARATA, J.

doi: 10.1046/j.1365-2133.1997.19392054.xpmid: N/A

SummaryBak (bel‐2 homologous antagonist/killer) is a proapoptotic member of the ever‐expanding bel‐2 gene family, a recently described category of oncogenes that is critical for the regulation of programmed cell death. We investigated the expression of bak in several inflammatory and neoplastic skin diseases in comparison with normal skin. Immunohistochemical analysis revealed positive bak staining in epidermal keratinocytes of normal skin, with the granular layer being stained slightly more strongly than the basal and spinous layers, and in psoriasis vulgaris, lichen planus, actinic keratosis, keratoacanthoma and squamous cell carcinoma. We demonstrated the expression of bak in the follicular infundibulum in contrast to the outer root sheath of the lower follicle, which showed only negative to weak bak expression. Seventeen of 20 basal cell carcinomas examined showed negative immunostaining for bak, and the remaining three basal cell carcinomas showed only partial weak positivity, mainly in the palisadin g layers of some tumour formations. Immunoblot analysis using cultured normal human epidermal keratinocytcs revealed the presence of bak protein in both undifferentiated and differentiated keratinocytes. The results of our study suggest that the loss of bak expression, in conjunction with the previously reported overexpression of bcl‐2, might contribute to the pathogenesis of basal cell carcinoma.

YAMAMOTO, T.; KATAYAMA, I.; NISHIOKA, K.

doi: 10.1046/j.1365-2133.1997.19402055.xpmid: N/A

SummaryStem cell factor (SCF) distribution in basal cell carcinomas (BCCs) was examined by immunohisto‐chemistry. Eighteen BCCs (11 nodular, three superficial, two cystic, one adenoid and one morphoeic type) showed positive expression of SCF in the tumour islands. The centre of the tumour island was strongly positive in nodular, superficial and morphoeic types. In cystic BCCs. SCF‐positive tumour cells were also located in the peripheral lesion around the cystic space. SCF was also detected on fibroblast‐like cells and mast cells in the stroma. SCF was positively stained within the upper keratinocytes in the overlying epidermis, more strongly as compared with normal skin. The mast cell number (mean ± SD)) was significantly increased in the peritumoral stroma (85.7 ± 28. 3/mm2) compared with normal skin (32.1 ±4.2/mm2) (P<0.005). SCF was also positive in the tumour nests of four cases of trichoepithelioma, in which fibrosis of the surrounding stroma was found histologically. This study demonstrates that abundant SCF produced by the tumour cells may account for the increased number of stromal mast cells, which induce fibroplasia of the surrounding stroma.

FAYYAZI, A.; SORURI, A.; RADZUN, H.J.; PETERS, J.H.; BERGER, H.

doi: 10.1046/j.1365-2133.1997.19412056.xpmid: N/A

SummaryPilomatrixoma is a benign tumour of the cutaneous adnexa. Histologically. pilomatrixoma comprises masses of immature basophilic cells, small numbers of polygonal squamoid cells, few transitional cells, and clusters of ‘shadow cells’. The mechanism leading to the formation of shadow cells is still unknown. Skin biopsy specimens of pilomatrixoma (n= 15) were studied histologically, immuno‐hislologically, and by applying the in situ end‐labelling technique. The basal layer of the basophilic cells included most of the proliferating cells with high expression of bcl‐2 and cytokeratin 19. The overlying basophilic cells showed a negligible mitotic activity, a high significant accumulation of p53 protein, and a heterogeneous, but progressive loss of bcl‐2 and cytokeratin 19. They developed either into squamoid cells or into transitional cells. The squamoid cells were characterized as differentiated cells resembling mature keratinocytes of stratified mucosa. The transitional cells could be shown to represent apoptotic cells proceeding to shadow cells. The data suggest that apoptosis is the main mechanism leading to the development of the dead shadow cells and is most probably responsible for the banal biological behaviour of pilomatrixoma. Apart from that, pilomatrixoma represents a suitable biological model to study apoptosis in humans.

BENATHAN, M.

doi: 10.1046/j.1365-2133.1997.19422057.xpmid: N/A

SummaryThe cellular concentration of reduced glutathione (GSH) modulates the sensitivity of human melanoma cells to alkylating drugs in vitro. To investigate whether the membrane‐associated enzyme γ‐glutamyl transpeptidase (γ‐GTP) involved in GSH breakdown was expressed in melanoma cells. the enzymatic activity of γ‐GTP as well as the secretion of GSH were measured in human melanoma cells from four different cell lines (Me8. JUSO, GLL19. Swift). All the cells showed low γ GTP activities (0–1 mU/mg protein) and released GSH in culture supernatants at significant rates. After incubation for 24 h in growth medium containing 0.1 mmol/L cystine, the levels of GSH in supernatants ranged from 56 to 111 nmol GSH/mg protein. The GSH metabolism of melanoma cells was also evaluated by measuring the levels of the melanogenesis intermediate 5‐S‐cysteinyldopa under different experimental conditions. The results of these experiments suggest that melanoma cells have a low ability to metabolize the tripeptide GSH. which appears to be responsible for GSH secretion and accumulation in culture supernatants.