ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Cultured melanoma cells have been of great value in the study of pigment metabolism. IGR 1 human melanoma cells, established by Dr Christian Aubert, produce melanin in large quantities. These cells have been used for isolation of human tyrosinase which enzyme has not previously been obtained in a pure form. IGR 1 cells contain large amounts of 5-S-cysteinyl-dopa which is the quantitatively most important catecholic amino acid. This review deals with the metabolism of dopa, cysteinyldopa, glutathionyldopa, cysteine and glutathione, compounds of central importance in pigment metabolism. The information available on tyrosinase, catecholic compounds and on thiols in IGR 1 melanoma cells makes these cells most suitable for further investigation of the metabolism of human melanoma cells.

ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The effect of a number of L-tyrosine (L-Tyr) analogues on L-Tyr uptake by B16/F10 malignant melanocytes is reported. This amino acid can be taken up by two of the most ubiquitous transport systems found in animals cells, L and presumably ASC. L-Tyr analogues devoid of the amino group, likep-hydroxyphenyl pyruvic acid and related compounds, and L-Tyr analogues devoid of the carboxyl group, such as tyramine, do not affect L-Tyr uptake. The other aromatic amino acids, L-Phe and L-Trp, and the L-Tyr analogues DL-m-Tyr, L-diiodotyrosine and L-dopa, strongly inhibit the uptake of L-Tyr. This suggests that these chemicals are transported more efficiently than L-Tyr. The ASC system does not show stereospecificity, but the L system has greater affinity for L-Tyr than for D-Tyr. The ASC system also has greater affinity for tyrosine isomers with the hydroxyl group in theorthoandmetapositions. The presence of a methyl group at the α-carbon of L-Tyr and L-dopa also increases the affinity of the ASC system for these agents. In contrast, α-methylation decreases the affinity of the L system in comparison to L-Tyr. Finally, L-Tyr esters do not inhibit, but stimulate the transport of L-Tyr, mainly by the ASC system.

ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Microdialysis was investigated as a tool for the determination of the extracellular concentration of the pigment metabolite 5-S-cysteinyldopa in human melanoma transplanted to athymic mice. Histology of the tumour with the microdialysis probesin situshowed no tissue damage. With probes equipped with polycarbonate membranes (20 kD) extraction (relative recovery) was approximately 50% at pH 4.0 and flow rates of 1 μl/min, but at pH 7.0 recoveries were markedly lower, particularly from serum. In a first series of human melanomas transplanted to athymic mice low concentrations of 5-S-cysteinyldopa were detected in only two out of ten dialysates and were not detected in the other eight. Utilizing devices constructed for comparison of membrane characteristicsin vitrowe found about 4-fold higher recoveries with cuprophane and polyamide membranes than with polycarbonate membranes. Therefore newly constructed microdialysis probes (CMA/11) with cuprophane membranes were testedin vitroand gave recoveries of 38–48% from Ringer-Acetate solutions and 22–31% from serum, and the pH effects were low. When these probes were utilized in a second series of melanomas transplanted to athymic mice, 5-S-cysteinyldopa could easily be quantified in 10/10 experiments. A steady-state level of the dialysate 5-S-cysteinyldopa concentration was reached after 45 min.

ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

A high-performance liquid chromatographic method with fluorometric detection is described which is suitable for determination of glutathione in small samples. Reduced glutathione (GSH) and total glutathione obtained as GSH after reduction with glutathione reductase is derivatized withN-(7-dimethylamino-4-methyl-3-coumarinyl) maleimide (DACM) and subjected to chro-matography. The detection limit for the GSH-DACM derivative was 5–10 fmol/injection, and analytical recovery was quantitative. The method is suitable for determination of both reduced and total glutathione in samples from microdialysis of melanoma tumours, and cysteine can be quantified in the same chromatogram. Application is shown also for glutathione determinations in cultured melanoma cells, melanoma homogenates and plasma.

ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

A 48 h pretreatment of two malignant and invasive human melanoma cell lines with either swainsonine (an inhibitor of Golgi alpha-mannosidase II) or deoxymannojirimycin (a Golgi alpha-mannosidase I inhibitor) resulted in a dose-dependent decrease in the cells' ability to invade a reconstituted basement membranein vitro. This effect was reversible within 48 h of removing the drugs. Treatment with either drug resulted in both cell lines being more resistant to the cytotoxic effects of the lectin leukoagglutinin (PHA-L) and more sensitive to the lectin concanavalin A which indirectly indicated a change in the cell surface oligosaccharide composition and structure consistent with the known effects of these drugs on N-linked oligosaccharide processing. A 25–33% decrease was noted in the adhesion of treated cells to either a reconstituted basement membrane or human umbilical vein endothelial cell monolayer while no change was measured in the cells' proliferative rates. A correlative decrease was observed, however, in the expression of human type IV collagenase mRNA which was recovered within 48 h of removing the drugs. These results suggest that a correlation exists between the drug-induced changes in the cell surface oligosaccharide composition and structure with a concomitant decrease in the mRNA and secreted levels of type IV collagenase and the ability of these cells to invade.

ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Between 1983 and 1990, 59 patients with malignant melanoma were retrospectively reviewed to assess the safety, efficacy and the maximal tolerated dose of cisplatin used in hyperthermic isolated limb perfusion. The median follow-up was 29 months (range 3–54 months). The local recurrence rate was 12% in Stage I, 33% in Stage II and 30% in Stage III patients. The maximal tolerated dose of cisplatin in hyperthermic isolated limb perfusion was 3.2 mg/kg for forequarter perfusions and 6 mg/kg for hindquarter perfusions based on lean body weight. At these dosages, there is an 8% major complication rate and only one patient experienced long-term sequelae. Hyperthermic isolated limb perfusion using cisplatin in the dosages of 3–6 mg/ kg lean body weight is associated with low morbidity and appears to have efficacy comparable to L-phenylalanine mustard for the control of locally recurrent malignant melanoma.

ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

This is a study of factors associated with late recurrence (i.e. 10 or more years after definitive surgery) of cutaneous malignant melanoma (MM). Four factors were evaluated: Breslow thickness, site of the primary MM, age of the patient at initial treatment for MM, and gender. These factors were compared between two groups: (1) Stage I cases in the New York University Melanoma Cooperative Group (NYU-MCG) database that had ‘early recurrence’ (<10 years) of MM, and (2) cases in the literature with late recurrence of MM plus five new cases reported here. Compared to the group of patients with ‘early recurrence' of MM, the group of patients who had late recurrence of MM were found more likely to have thinner primary melanomas (p< 0.001), to be younger (p> 0.001), to be female (p=0.001), and, for females, to have the MM located on an extremity (p= 0.017). Because late recurrence does occur and because the risk of developing a new primary MM is increased in MM patients, any patient who has had a MM should be followed for life.

ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Two recently published case-control studies have highlighted the possibility of an association between the development of cutaneous malignant melanoma and exposure to sunlamps and sunbeds. Little is known about the behaviour patterns with regard to exposure to sunlamps and sunbeds in Western Europe. This descriptive study compares usage patterns of sunlamps and sunbeds of melanoma patients with the general population in Belgium. Evidence is given that melanoma patients are greater users of artificial ultraviolet sources than the general population, and that the incidence of melanoma in different geographical areas increases proportional to the percentage of people using tanning devices. Although this descriptive study may well be biased or refuted, it does advocate the need for further epidemiological research addressing specifically the issue of melanoma and exposure to artificial sources of ultraviolet radiation.

ISSN:0960-8931    

出版商:OVID    

年代:1991

数据来源: OVID