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At least 19 recordsLinked to original sources
PubMed1988

Plasma 5-S-cysteinyldopa differentiates patients with primary and metastatic melanoma from patients with dysplastic nevus syndrome and normal subjects.

To determine whether plasma 5-S-cysteinyldopa levels are useful in following up patients at risk for melanoma, we measured plasma 5-S-cysteinyldopa in patients with dysplastic nevus syndrome and/or malignant melanoma and in control subjects. In patients with dysplastic nevus syndrome, plasma 5-S-cysteinyldopa levels did not differ from those in control subjects. Conversely, patients with malignant melanomas had significantly higher plasma 5-S-cysteinyldopa levels than did controls. Those with localized cutaneous malignant melanoma and no distant metastases (Stage I and II disease) had 5-S-cysteinyldopa levels twofold greater than those of control subjects, whereas the levels of those with regional lymph node involvement (Stage III disease) were fourfold greater than those of control subjects. Levels of those with extraregional metastases (Stage IV disease) were 7- to 450-fold higher than those of control subjects. Moreover, plasma 5-S-cysteinyldopa levels correlated with the spread of disease and were useful in distinguishing primary melanoma and Stages III and IV melanoma. We conclude that plasma 5-S-cysteinyldopa may be an important tool for identifying melanoma at an earlier, more curable stage and for following up patients at risk for the development of melanoma, for example, those with dysplastic nervus syndrome.

Adult↗
PubMed1975

Urinary excretion of 5-S-cysteinyldopa in patients with primary melanoma or melanoma metastasis.

Urinary excretion of 5-S-cysteinyldopa was studied in 9 patients with primary melanoma. All had 5-S-cysteinyldopa excretion in the normal range. In 8 of the patients excretion values decreased after removal of the tumour. Twenty-four patients with clinical signs of melanoma metastasis were examined for 5-S-cysteinyldopa and dopa+dopamine in the urine. 16 of the 24 had pathologically increased excretion of 5-S-cysteinyldopa and 7 of the 24 had pathological excretion of dopa+dopamine. Six of the latter belonged to the group with increased 5-S-cysteinyldopa excretion and one patient had a borderline value of 5-S-cysteinyldopa. Determination of 5-S-cysteinyldopa seems to be of value in the follow-up of patients operated on for primary melanoma.

Adult↗
PubMed1978

The urinary melanogen cysteinyldopa in melanoma and in suntanning: Australian experience.

Determination of urine cysteinyldopa excretion is the most sensitive chemical test for the detection of melanoma metastases and has been successfully applied during the Scandinavian winter, when sun irradiation is low. The value of this determination, under Australian conditions of greater sun irradiation, has been assessed by comparing the cysteinyldopa excretion of patients with that of normal subjects exposed to sunlight. Cysteinyldopa is an intermediate in the biosynthesis of the red-brown phaeomelanin. Of 20 patients without known secondary melanoma, the cysteinyldopa concentration of "spot" urines ranged from 0 to 190 (mean 48) microgram/ml; of six known to have local metastases, 0 to 80 (mean 19) microgram/ml; and of four known to have extensive metastases 80 to 1350 (mean 330) microgram/ml. The effect of sun irradiation alone was assessed in nine healthy subjects followed one to 11 weeks before and after recorded periods of sun exposure. The cysteinyldopa concentrations of 24-hour urines ranged from 40 to 3100 microgram/ml. Increases occurred three to 10 days following sun exposure and were greatest following multiple small exposures in an individual with "Celtic" complexion. It is concluded that measurement of cysteinyldopa concentration would be of value in the follow-up of melanoma patients in Australia only if patients could be persuaded to live under conditions free of all direct sun-irradiation.

Adolescent↗
PubMed1976

On the occurrence of cysteinyldopa and dopa in melanocytes and benign nevi cells.

Previous studies have demonstrated a specific cytoplasmic fluorescence in human melanocytes, as well as in pigmented nevi and in malignant melanomas, when the formaldehyde histofluorescence method for visualization of certain catechol and indole derivatives was used. In malignant melanoma two fluorogenic substances, dopa and cysteinyldopa, were found previously. In human melanocytes and benign nevi cells the fluorogenic catechols have so far not been characterized, since chemical analyses are difficult to perform on skin, due to the small amounts of catechols present. However, using split thickness skin quantitative determinations are possible by sensitive fluorometric methods. The chemical analyses of cysteinyldopa showed that in human adult skin most or all was located in the superficial layers. The only specific fluorescence in the thin skin was found in dendritic melanocytes. The findings leave little doubt that cysteinyldopa is stored in melanocytes although the possibility of a concomitant occurrence of other thioethers is not excluded. Nevi and giant nevi were also similarly studied and we found considerable amounts of cysteinyldopa in the nevi. It seems as if the cysteinyldopa is stored in the fluorescent nevi cells. There was no consistent difference in the content of the catechol derivatives between intradermal and compound nevi.

Adolescent↗
PubMed1978

The quantitative determination of 5-S-cysteinyldopa and dopa in normal serum and in serum from patients with malignant melanoma by means of high-pressure liquid chromatography.

A method is described for quantitative determination of 5-S-cysteinyldopa and Dopa in serum involving high-pressure liquid chromatographic analysis (HPLC) and electrochemical detection. The chromatographic system allows estimation of injected amounts corresponding to 25 pg of 5-S-cysteinyldopa and Dopa. In normal subjects the mean serum 5-S-cysteinyldopa concentration was 2.8 ng/ml (range 0.4--12 ng/ml) and the mean serum Dopa 6.3 ng/ml (range 4--10 ng/ml). Patients with melanoma metastases showed increased serum concentrations of 5-S-cysteinyldopa.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Microdialysis of 5-S-cysteinyldopa from interstitial fluid in cutaneous human melanoma transplanted to athymic mice.

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.

Animals↗
PubMed1979

5 years' experience of 5-S-cysteinyldopa in melanoma diagnosis.

Determinations of the urinary excretion of 5-S-cysteinyldopa were performed in 571 patients previously treated by surgery for melanoma or melanoma metastasis. 90% of the 161 patients with metastases showed values exceeding 0.15 mg/24 h, and 9% of the 410 patients without metastases had such values. The increase in 5-S-cysteinyldopa excretion was generally more pronounced in men with metastases than in women, 98% of the men and 77% of the women with metastases showing values exceeding 0.15 mg/24 h. High levels of 5-S-cysteinyldopa are of grave prognostic significan4% died within one month, and only 3% survived for more than a year. In Sweden, determination of 5-S-cysteinyldopa in patients operated on for melanoma gives maximum information in the winter (October--March), when sun exposure does not influence the excretion levels.

Adult↗
PubMed1975

Formation of cysteinyldopa from glutathionedopa in melanoma.

Glutathionedopa injected intravenously into mice is metabolized and excreted in the urine as a compound with the fluorescence characteristics of cysteinyldopa. Glutathionedopa incubated with a guinea-pig kidney homogenate is metabolized to a compound with the fluorescence characteristics of cysteinyldopa. Boiling of the kidney homogenate prevents the metabolism of glutathionedopa. Incubation of glutathionedopa with a homogenate of a melanoma metastasis led to the formation of a compound with the fluorescence characteristics of cysteinyldopa. Boiling of the melanoma homogenate prevented the metabolism of glutathionedopa. Large amounts of glutathione added to the incubate inhibited the reaction. Lung tissue and blood plasma had no detectable ability to metabolize glutathionedopa. The results show that human melanoma contains one or several enzymes capable of metabolizing glutathionedopa to a smaller dopathioether, probably cysteinyldopa. Such enzymes seem to be normally present in mice and guinea-pigs and have been demonstrated in the guinea-pig kidney.

Animals↗
PubMed1977

A facile one-step synthesis of cysteinyldopas using mushroom tyrosinase.

A convenient one-step procedure, based upon the tyrosinase co-oxidation of dopa and cysteine, is reported for the synthesis of 5-S-cysteinyldopa (I) in 74% yield. Secondary products of the reaction turned out to be 2-S-cysteinyldopa (II, 14%), 2,5-S, S-dicysteinyldopa (iv, 5%), and the hitherto unknown 6-S-cysteinyldopa (III, approximately 1%).

Cysteinyldopa↗
PubMed1978

5-S-cysteinyldopa excretion after treatment with 8-methoxypsoralen and UVA light.

The excretion of the specific melanocytic metabolite 5-S-cysteinyldopa was studied in patients with psoriasis treated by 8-methoxypsoralen and UVA light. A pronounced increase was found after only 2 days treatment, although no increase in pigmentation could yet be observed. Peak values for urinary 5-S-cysteinyldopa were noted after 1 or 2 weeks treatment. Increase in pigmentation persisted after the excretion maxima for 5-S-cysteinyldopa.

Adult↗
PubMed1985

Plasma 5-S-cysteinyldopa concentrations in oculocutaneous albinism.

5-S-cysteinyldopa concentrations were determined by high-pressure liquid chromatography and electrochemical detection in plasma from normally pigmented patients and patients with oculocutaneous albinism, both tyrosinase-positive and tyrosinase-negative. The plasma 5-S-cysteinyldopa concentrations were similar in all three groups, suggesting that 5-S-cysteinyldopa can be produced by mechanisms which do not involve tyrosinase.

Albinism↗
PubMed1977

5-S-cysteinyldopa in the urine of melanoma patients.

A newly discovered amino acid, 5-S-cysteinyldopa, present in the urine of healthy subjects is excreted in pathological amounts in many patients suffering from melanoma metastases. Increased excretion of 5-S-cysteinyldopa may be observed before metastases become clinically evident. Determination of 5-S-cysteinyldopa is superior to determination of dopa+dopamine in the diagnosis of melanoma metastases.

Adult↗
PubMed1978

Free and bound 5-S-cysteinyldopa and dopa in human malignant melanomas.

Free dopa and 5-S-cysteinyldopa were extracted from two human melanomas. Subsequent hydrolysis of carefully washed melanoma tissue released dopa and 5-S-cysteinyldopa, indication the presence of these catechol amino acids in proteins. Cysteinyldopa-containing proteins may represent the antigens previously demonstrated in human melanomas.

Cysteinyldopa↗
PubMed1979

Intracellular distribution of dopa and 5-S-cysteinyldopa in pigment cells with minimal pigment formation.

The hypothesis that only melanosomal catecholic amino acids contribute to melanin formation was tested by studying adult bovine eyes in which pigment synthesis is considered to be low or absent. Dopa and 5-S-cysteinyldopa were investigated in different cell fractions of the choroid and retinal pigment epithelium of cattle. Most of the dopa and 5-S-cysteinyldopa was found in the cytoplasm and very little in the large granule fraction. The presence of cysteinyldopa in the adult eye is evidence of tyrosinase activity, but the catechol amino acids in the cytoplasm probably do not give rise to melanin formation. It is assumed that they instead are excreted from the cells.

Animals↗
PubMed1992

The stability of 5-S-cysteinyldopa and 6-hydroxy-5-methoxyindole-2-carboxylic acid in human urine.

5-S-cysteinyldopa and 6-hydroxy-5-methoxyindole-2-carboxylic acid are important intermediate metabolites in the formation of cutaneous melanin pigment. Since they both are serious candidates as markers of melanoma progression, their stability in urine has been investigated during storage at various conditions. The results show that storage at -20 degrees C is necessary. Both compounds are nonstable at room temperature, particularly if the urine was not acidified to pH 4-5. Reference levels were obtained from analysis of urine from 31 men and 40 women. The mean (SD) excretion of 5-S-cysteinyldopa was 32 (12.5) mumol/mol creatinine (women). Corresponding figures for 6H5MI2C were 23 (10.3) and 24 (8.1) mumol/mol creatinine for men and women respectively.

Adult↗
PubMed1977

Intracellular distribution of dopa and 5-S-cysteinyldopa in Harding-Passey melanoma.

The concentrations of dopa and 5-S-cysteinyldopa were determined in the various cell fractions of Harding-Passey melanomas. Dopa was present in larger amounts than was 5-S-cysteinyldopa in all cell fractions, but the dopa/5-S-cysteinyldopa ratio was lower in the soluble fraction and in the small-granule fraction than in the large-granule fraction. The soluble fraction contained the greatest amount of catechols. These findings are compatible with high tyrosinase activity not only in the melanosomes but also in the small-granule and soluble fractions.

Animals↗
PubMed1975

Differentiation of melanocytes in cultures of primary malignant melanoma indicated by 5-S-cysteinyldopa formation.

The dedifferentiation of cultured primary human malignant melanocytes was not accompanied by disappearance of 5-S-cysteinyldopa formation. The addition of conditioned medium from undifferentiated fibroblast-like cells brought about the reappearance of pigmented melanocytes and the increase of the metabolite in the cells and culture medium. The presence of 5-S-cysteinyldopa in cultured cells indicated the melanocytic origin of undifferentiated cells, and the increase of this metabolite was characteristic of differentiation.

Cell Differentiation↗