| 1. |
- Blomquist, L., et al.
(författare)
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Microdialysis of 5-S-cysteinyldopa from interstitial fluid in cutaneous human melanoma transplanted to athymic mice
- 1991
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Ingår i: Melanoma Research. - 0960-8931. ; 1:1, s. 23-32
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Tidskriftsartikel (refereegranskat)abstract
- 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 probes in situ showed 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 microliter/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 characteristics in vitro we 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 tested in vitro and 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.
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| 2. |
- Dizdar (Dizdar Segrell), Nil, et al.
(författare)
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A high-sensitivity fluorometric high-performance liquid chromatographic method for determination of glutathione and other thiols in cultured melanoma cells, microdialysis samples from melanoma tissue, and blood plasma.
- 1991
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Ingår i: Melanoma Research. - 0960-8931. ; 1:1, s. 33-42
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Tidskriftsartikel (refereegranskat)abstract
- 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 with N-(7-dimethylamino-4-methyl-3-coumarinyl) maleimide (DACM) and subjected to chromatography. 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.
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| 3. |
- Stierner, Ulrika, 1952, et al.
(författare)
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Regional distribution of common and dysplastic naevi in relation to melanoma site and sun exposure. A case-control study.
- 1992
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Ingår i: Melanoma research. - 0960-8931. ; 1:5-6, s. 367-75
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Tidskriftsartikel (refereegranskat)abstract
- The frequency of melanoma (CMM), and of common and dysplastic naevi (CN and DN) in areas of skin chronically, intermittently and rarely exposed to UV light was investigated in 121 melanoma patients (30-50 years) and 310 controls. Both cases and controls had significantly more CN in intermittently exposed areas than in areas chronically or rarely exposed. The ratio of observed to expected number of CMM was also highest in intermittently exposed skin (1.3 compared to 0.8 in chronically exposed and 0.5 in rarely exposed areas). Thus, intermittent UV exposure seems to have the most potent 'naevogenic' as well as carcinogenic effect on melanocytes. Nineteen per cent of controls and 56% of cases had naevi fulfilling the clinical criteria for DN. The distribution pattern of DN was clearly different from that of CN and does not accord with the idea that UV light is a major aetiological factor for DN. The probability of CMM significantly increased with the degree of relative clustering of CN (p less than 0.05) and of DN (p less than 0.01). This co-variation of naevi and CMM over the body surface might be the result of the local insults to the melanocyte system caused by UV light and/or to the fact that naevi are precursor lesions of CMM.
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