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Biomedical subjects

H Rorsman

Publications and source records attributed to H Rorsman.

At least 91 records · Page 5Linked to original sources
PubMed1979

Electron spin resonance studies on phaeomelanins.

ESR spectra of synthetic melanins formed from dopa and from 5-S-cysteinyldopa and of melanins isolated from human melanomas were studied. Alkali-soluble melanin synthesized from cysteinyldopa showed a signal similar to that of insoluble melanin synthesized from dopa, but also a simple fine structure. Trichochromes C and F synthesized from 5-S-cysteinyldopa had a broader signal than dopamelanin, and in addition a hyperfine structure that could be explained by the presence of manganous ions. An insoluble eumelanin from a human melanoma with a sulphur content of 5% showed an ESR spectrum consisting of one line like dopamelanin. An alkali-soluble phaeomelanin from a human melanoma with a sulphur content of 10% showed a very broad signal with a hyperfine structure that could be explained by the presence of manganous ions.

Chemical Phenomena↗
PubMed1979

Diffuse melanosis and trichochromuria in malignant melanoma.

A previous finding of pronounced excretion of trichochromes in a patient with metastasizing melanoma and diffuse melanosis prompted this study on trichochromes in another patient with these two features. The patient now reported also excreted large amounts of trichochromes. Iit is suggested that diffuse melanosis in metastatic melanoma patients is due to deposition of trichochromes in the tissue.

Adult↗
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↗
PubMed1978

Trichochromes in the urine of melanoma patients.

The urine of patients with melanoma metastases and increased urinary excretion of 5-S-cysteinyldopa was examined for trichochromes. Five of 16 patients showed urinary excretion of trichochromes B and C. None excreted trichochromes E or F. All patients showing trichochrome excretion had very large amounts of cysteinyldopa in their urine.

Adult↗
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↗
PubMed1978

5-S-cysteinyldopa and trichochromes in red feathers.

Red cock feathers (Rhode Island) were found to contain dopa and cysteinyldopa, trichochromes B and C, and two unidentified trichochromes. Trichochromes E and F were not found. Previous findings of trichochromes E and F may be explained as artifacts.

Animals↗
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↗
PubMed1978

Trichochromes in red human hair.

The presence of trichochromes B and C in red human hair was confirmed with an analytical procedure which does not give rise to the formation of these compounds as artifacts. The trichochrome precursor 5-S-cysteinyldopa previously demonstrated in red guinea-pig hair was not detected in red human hair.

Adolescent↗
PubMed1978

Trichochromes in human malignant melanoma.

Decarboxytrichochromes B and C were isolated from a melanoma metastasis in a red-haired man, indicating the presence of trichochromes B and C in the tissue. Trichochromes E and F were not detected.

Adult↗
PubMed1977

Fluorescence histochemical demonstration of dopa thioethers by condensation with gaseous formaldehyde.

The usefulness of the formaldehyde (FA) and glyoxylic acid (GA) methods for the fluorescence histochemical demonstration of dopa thioethers has been tested using protein droplet models. Similar fluorescence intensities were recorded from these compounds after either FA or GA treatment. Cysteinyldopa gave a high fluorescence yield similar to that obtained from dopamine and dopa in the FA reaction, whereas gluatitodopa showed a lower, although clearly visible fluorescence. Since the FA method seemed to be the most useful one for demonstration of catechol thioethers, the FA-induced fluorophores of these compounds were further characterized by microspectrofluorometry. The spectral characteristics of the thioether fluorophores (excitation maxima at 420 nm and emission maxima at 480-485 nm) distinguish these substances from dopa and other compounds fluorogenic in the Falck-Hillarp method. Dopa thioethers are proposed to form fluorophores with FA in a manner analogous to that of the primary catecholamines i.e. via low-fluorescent tetrahydroisoquinolines, along two different pathways, to strongly fluorescent 3,4-dihydroisoquinolines and 2-methyl-dihydroisoquinolinium compounds. These dihydroisoquinolines are in a pH-dependent tautomeric equilbrium with their quinoidal forms as reflected by a characteristic spectral shift upon acidification. The results of this study provide the guide-lines for the characterization of fluorogenic compounds in pigment-forming cells.

Cysteinyldopa↗
PubMed1977

Metabolism of 5-S-cyteinyldopa by O-methylation.

5-S-cysteinyldopa is metabolized by O-methylation on incubation with a liver extract and S-adenosyl methionine. O-methylated 5-S-cysteinyldopa isolated from melanoma urines by ion exchange and paper chromatography was identified by gas chromatography-mass spectrometry and NMR.

Animals↗
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↗
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↗