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PubMed1999

Determination of 5-S-cysteinyldopa in plasma and urine using a fully automated solid-phase extraction--high-performance liquid chromatographic method for an improvement of specificity and sensitivity of this prognostic marker of malignant melanoma.

5-S-Cysteinyldopa (5-SCD) in plasma and urine was determined by means of a newly developed method. This method incorporates optimized conditions for blood collection and storage, as well as a new extraction and separation technique, required for the strong oxidation and light sensitive 5-SCD. The new aspects of the method are the following: immediate centrifugation and freezing of the samples after blood collection, fully automatical solid-phase extraction (SPE) with phenylboronic acid (PBA) cartridges and immediate HPLC injection of the eluate, nearly complete exclusion of light and air-oxygen during extraction, constant sample cooling, use of the more suitable internal standard 5-S-D-cysteinyldopa and easy, sensitive and selective HPLC conditions (RP18-column with isocratic separation and electrochemical detection). The method has a linear range from 0.25 to 50 microg l(-1) and 25 to 5000 microg l(-1) for plasma and urine samples, respectively, a limit of detection of 0.17 microg l(-1), intra-assay variabilities from 1.7 to 3.6%, inter-assay variabilities from 4.0 to 18.3% and an average relative recovery of 103.5% for plasma and 105.4% for urine samples. In our study the measured 5-SCD concentrations of patients with melanomas at various stages correlated better with their clinical pictures than described in literature up to date. The results were obtained in comparison to patients with other skin tumors and in comparison to healthy control persons.

Automation↗
PubMed2004

Improved method for analysis of cysteinyldopa in human serum.

5-S-L-Cysteinyl-L-dopa is a well-known pigment intermediate and analysis of its serum concentration is well suited for evaluation of treatment and follow-up of stage III and IV malignant melanoma. A simplified analytical method is described using organic extraction followed by clean-up on a boronate gel to capture the compound containing vicinal hydroxyls. Weak acid solution elutes the 5-S-cysteinyldopa suitable for high-performance liquid chromatography (HPLC). The absolute recoveries of cysteinyldopa and its diastereomer 5-S-D-cysteinyl-L-dopa (used as an internal standard) were 81.5 +/- 2.8% and 81.3 +/- 2.7%, respectively, and use of the internal standard for the whole procedure gave an analytical recovery of 101 +/- 0.8%. The limit of quantitation was 1.5 nmol/L and the imprecision of the method was < 5.0% over the analytical range 1.5-500 nmol/L. The method is cheap and easy to perform and compares well with other described techniques. The use of the method is illustrated by results obtained during treatment of a patient with metastatic malignant melanoma.

Aged↗
PubMed1997

Effects on interstitial glutathione, cysteine and 5-S-cysteinyldopa of buthionine sulphoximine in human melanoma transplants.

Using microdialysis of human melanoma transplants in athymic mice we have shown that interstitial glutathione levels decreased during treatment with buthionine sulphoximine (BSO) and recovered after cessation of treatment. The cysteine concentrations also decreased, while 5-S-cysteinyldopa tended to increase during BSO treatment. Restoration of the glutathione levels was not seen after either N-acetylcysteine (NAC) or L-2-oxothiazolidine-4-carboxylate (OTC) injections, given on the third day of BSO treatment. These results were to be expected since NAC and OTC were given during the BSO treatment, and BSO is a specific and potent inhibitor of glutathione synthesis. Cysteine levels, however, increased after the NAC injection but remained unaltered after the OTC injection, while 5-S-cysteinyldopa remained unaltered after both the NAC and the OTC injections.

Acetylcysteine↗
PubMed2003

Comparison of phaeomelanin and its precursor 5-S-cysteinyldopa in the serum of melanoma patients.

5-S-Cysteinyldopa (5-S-CD) has been used as a biochemical marker of melanoma progression. Recently we have shown that the serum level of 5-S-CD is a sensitive and specific marker in predicting distant metastases. In melanocytes and melanoma cells, cysteinyldopa isomers are oxidized to phaeomelanin, the yellow to reddish melanin pigment. In this study we have developed a new method to measure levels of phaeomelanin in serum samples and have evaluated its clinical significance. The method is based on the production of 4-amino-3-hydroxyphenylalanine (4-AHP) and 3-amino-4-hydroxyphenylalanine (3-AHP) on reductive hydrolysis of phaeomelanin with hydriodic acid. 3-AHP is also derived from 3-nitrotyrosine-containing proteins. The isomeric 4-AHP and 3-AHP can be separated by high performance liquid chromatography. The mean +/- SD serum levels of 5-S-CD in control subjects (n = 36), in melanoma patients without recurrence (n = 92) and in melanoma patients with metastases (n = 24) were 2.7 +/- 1.2 nM (median 2.3 nM), 4.0 +/- 1.6 nM (median 3.8 nM) and 72 +/- 105 nM (median 35 nM), respectively. The serum levels of 4-AHP in these three groups were 45 +/- 21 nM (median 31 nM), 80 +/- 75 nM (median 53 nM) and 306 +/- 627 nM (median 133 nM), respectively. The serum levels of 4-AHP in patients with metastases (100 samples from 15 patients with progressive disease) correlated well (r = 0.887) with serum levels of 5-S-CD, while serum levels of 3-AHP did not (r = 0.240). The serum 5-S-CD and 4-AHP levels were serially analysed in the 15 patients with progressive disease. In two patients (13%), serum 4-AHP levels were elevated to abnormal levels before the serum 5-S-CD levels exceeded the cut-off value of 10 nM. In five patients (33%), the serum 4-AHP levels rose concurrently with the serum 5-S-CD levels. In the remaining eight patients (54%), serum 4-AHP levels were of less diagnostic value. Thus, the serum phaeomelanin level appears to be less sensitive than the serum 5-S-CD level in detecting distant metastases.

Adult↗
PubMed1984

Characterization of melanogenesis in mouse and guinea pig hair by chemical analysis of melanins and of free and bound dopa and 5-S-cysteinyldopa.

This study examined how various genotypes of coat color in mice and guinea pigs are related to the type and content of melanin and to the levels of free and protein-bound dopa and 5-S-cysteinyldopa in hair. In analysis of black, yellow, and white areas of tortoiseshell guinea pigs, the melanogenesis type was in parallel to the type and content of melanin and was correlated fairly well with the levels of melanin precursors. In mouse hair, substitution of the brown allele (bb) for black (BB) reduced the eumelanin content to 1/2 to 1/3, while it significantly increased the dopa level. The dilution (dd) gene of mice reduced the eumelanin content only slightly, while the gene for pink-eyed dilution (pp) reduced the content of eumelanin and the level of dopa to as much as 1/10. From the eumelanin/pheomelanin ratio, the melanin of brown and dilute brown mice was found to be eumelanic, while the melanin of pink-eyed dilution mice appeared to be a mixed type because of an extremely low content of eumelanin. The levels of bound dopa and 5-S-cysteinyldopa in hair were found to largely reflect the tyrosinase activity.

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↗
PubMed1997

Insulin inhibits tyrosinase activity and 5-S-cysteinyldopa formation in human melanoma cells.

The effects of insulin on melanogenesis were examined in human Swift melanoma cells. When these cells were grown in a chemically defined culture medium containing insulin (5 microg/ml), they showed a low pigmentation in association with a high activity of glutathione peroxidase (GPO) and a low activity of tyrosinase. In Eagle's minimum essential medium supplemented with foetal calf serum (EMEM-FCS), the Swift cells showed an intense pigmentation in association with a low GPO activity and a high tyrosinase activity. Modulation of GPO activity with sodium selenite had no effect on melanogenesis variables. In contrast, addition of insulin (5 microg/ml) to the EMEM medium led to a marked decrease in tyrosinase activity (p<0.001) and to a concomitant reduction in the levels of 5-S-cysteinyldopa (p <0.01). These results indicate that insulin inhibits the formation of 5-S-cysteinyldopa and that of melanin via the inhibition of tyrosinase activity.

Calcium↗
PubMed1980

5-S-cysteinyldopa, dopa, and dopamine in the kidney and some other tissues.

5-S-Cysteinyldopa, dopa, and dopamine levels were determined by HPLC and electrochemical detection in serum, urine, kidney, spleen, heart, and sympathetic ganglion of guinea-pig. The kidney showed high levels of 5-S-cysteinyldopa, but also of dopa and dopamine, thus demonstrating the role of the renal ti-sue in the excretion of these substances. The concentrations found in spleen and heart may indicate specific catechol-containing structures in these organs.

Animals↗
PubMed1980

Dopa and 5-S-cysteinyldopa in the serum of albino, black, and red guinea pigs.

Dopa and 5-S-cysteinyldopa levels in serum of albino, red, and black guinea-pigs were quantified. The levels of both amino acids were lower in the albino than in the pigmented animals. It is suggested that the serum levels of dopa and 5-S-cysteinyldopa in pigmented animals reflect tyrosine and dopa oxidation activity in the melanocytes.

Animals↗
PubMed1983

5-S-cysteinyldopa and pigment response to UVA light.

5-S-Cysteinyldopa concentrations in serum were studied in healthy individuals exposed to daily high-intensity UVA radiation. A marked increase in 5-S-cysteinyldopa was found after 3 days, and in some individuals concentrations were still higher after 7 to 10 days. The immediate pigment darkening (IPD) and delayed tanning (DT) were weak or absent at pressure sites, i.e. in skin with a low concentration of oxygen.

Adult↗
PubMed1983

[5-S-cysteinyldopa determination in the urine. Its value for monitoring in melanoma patients].

In case of uncharacteristic patient complaints or slightly pathologic BSR or liver enzyme levels in patients, suffering from melanoma, the determination of 5-S-cysteinyldopa in the 24-h-urine may be of great diagnostic value. If the complaints and the pathologic values are early symptoms and signs of generalized metastases being clinically not yet manifest, the excretion of 5-S-cysteinyldopa in the urine is often increased. In such cases, a thorough and possibly invasive search for metastases is indicated.

Cysteinyldopa↗
PubMed1984

[A newly established melanoma cell line (GAK) with 5-S-cysteinyldopa phenotype].

The production of 5-S-cysteinyldopa by a newly established melanoma cell line GAK is reported. The cell line was derived from a metastatic inguinal lymph node of vulvar malignant melanoma. The cell line grew well without interruption for over 4 years, GAK cells were proved to have melanin granules and tyrosinase activity in their cytoplasma by Masson's staining and dopa reaction, respectively. Melanin granules were ultrastructually identified as melanosomes in various maturing stages. The chromosomal number varied widely and showed aneuploidly, but the modal chromosomal number was stable in the hypotriploid range. GAK cells were transplanted to nude mice and produced tumors resembling the original. Because glucose-6-phosphate dehydrogenase of GAK revealed a type B (slow) mobility pattern on electrophoresis, the possibility of Hela cell contamination could be completely excluded. High performance liquid chromatography revealed "5-S-cysteinyldopa", a new tumor marker of malignant melanoma, in culture media of GAK cells. The cell line described may serve as a representative model system for basic and clinical studies on malignant melanoma.

Aged↗
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↗
PubMed1975

Excretion of 5-S-cysteinyldopa in the urine of healthy subjects.

Seventy-six Caucasians, 30 men and 46 women, were investigated for the 24-hour excretion of 5-S-cysteinyl dopa in the urine during the months of September to November, 1973. No subject had had strong sun exposure for at least 4 weeks prior. A preliminary finding of a variation of 5-S-cysteinyldopa with season necessitated this precaution. The excretion varied between 9.0 and 242 mug/24 hours. The mean value in men was 100 mug/24 hours and in women 77.8 mug/24 hours. Subjects with white hair had lower values than those with pigmented hair, but there was no other difference between the excreted amounts in subjects with differing hair colour. There was no variation with age when the subjects with white hair were excluded. No variation with weight or body surface was found. Excretion of dopa and dopamine determined together did not correlate with the excretion of 5-S-cysteinyldopa.

Adolescent↗
PubMed1999

Increased serum levels of 5-S-cysteinyldopa and intercellular adhesion molecule-1 in a patient with a uterine amelanotic metastasis from a primary vaginal malignant melanoma.

A 75-year-old Japanese woman, who had an enlarged uterus and two nodules on the anterior vaginal wall, underwent wide excision of the anterior vaginal wall, bilateral inguinal lymphadenectomy, modified radical hysterectomy, and pelvic lymph node dissection. Her serum level of 5-S-cysteinyldopa (5-S-CD) was elevated, but her serum intercellular adhesion molecule-1 (ICAM-1) level was within normal limits. Histologic examination of the vaginal wall revealed atypical melanocytes at the dermoepidermal junction and numerous melanin-containing granules in the cytoplasm of the tumor cells. The tumor in the uterus consisted of sheets of anaplastic cells with evidence of diminished melanization. Five months after her initial presentation, she developed a recurrence and expired. The serum level of ICAM-1 was beyond the normal limit at the time of recurrence. Both the serum 5-S-CD and the ICAM-1 levels became elevated after recurrence and appeared to be correlated with disease progression.

Aged↗
PubMed1996

Cysteine-dependent 5-S-cysteinyldopa formation and its regulation by glutathione in normal epidermal melanocytes.

Recent evidence suggests that the melanogenesis intermediate 5-S-cysteinyldopa (5-S-CD) could display antioxidative activity. In the present study, the synthesis of 5-S-CD was examined in human epidermal melanocytes isolated from dark skin type VI (MT) and from white skin type III (GT). The MT melanocytes showed the higher melanin content and dopa oxidase activity. In addition, they produced eumelanin as shown by their ultrastructure, and the solubility and UV/visible absorption of the isolated pigment. Both MT and GT cells showed high levels of 5-S-CD (5.5-6.9 nmol/mg protein). 5-S-CD was also detected in culture supernatants from MT cells; the secretion rate was estimated to be 2.5 nmol/mg protein per 24 h. The role of cysteine and glutathione in 5-S-CD formation was investigated by exposing the melanocytes to the gamma-glutamylcysteine synthetase inhibitor L-buthionine sulfoximine (BSO). A strong reduction in glutathione levels (4-8% of the untreated controls) associated with an increase in cysteine levels (152-154%) was observed. In addition, BSO induced a moderate increase in the cellular levels of 5-S-CD (114-129%) and a decrease in dopa oxidase activity (75-83%). Our results indicate that the direct addition of cysteine to dopaquinone is the main source of 5-S-CD in human epidermal melanocytes. It is proposed that the synthesis of 5-S-CD is a mechanism regulating dopaquinone levels during pigment formation and/or a defence mechanism against oxidative stress.

Buthionine Sulfoximine↗