[Left hemifacial flushing and sweating].
Explore the source record for details and available documents.
Autonomic Fibers, Preganglionic↗
Biomedical subjects
A Wilczek
Publications and source records attributed to A Wilczek.
Penicillin G does not alter collagen type I metabolism of dermal fibroblasts in culture.
BACKGROUND: Penicillin G (PenG) has successfully been used for therapy of dermal fibrosis in patients suffering from systemic sclerosis (SSc). However, there is little knowledge on the mechanism of the antifibrotic action of PenG. OBJECTIVE: We studied the effects of PenG on dermal fibroblasts by analysing the influence of various amounts of PenG on the proliferation, synthesis and degradation of collagen by human dermal fibroblasts from healthy donors and 1 SSc patient (collagen high producer). METHODS: Collagen metabolism of cultured dermal fibroblasts was studied by Northern hybridisation for mRNA of collagen I, proline-4-hydroxylase, lysyl hydroxylase, matrix metalloproteinase I and determination of collagen content in culture supernatants. RESULTS: PenG did not alter the expression of the investigated mRNA, independently of the dosage and the incubation times used. The amount of collagen I protein was not influenced. CONCLUSION: There is no evidence of a direct antifibrotic effect of PenG on dermal fibroblasts; therefore, other mechanisms might be responsible for its effect in the treatment of SSc patients.
Cell Division↗
Symptoms and character traits in patients selected for long-term psychodynamic psychotherapy.
In this naturalistic study of 55 outpatients selected for long-term psychodynamic psychotherapy, two Swedish assessment instruments are presented (the Karolinska Psychodynamic Profile and the Karolinska Scales of Personality), and the significance of psychodynamic criteria for the selection of patients is discussed. Thirty patients (55%) fulfilled criteria for a DSM-III-R diagnosis. The most prominent psychodynamically defined character pathology was found in the areas of coping with aggressive affects; dependency and separation; frustration tolerance; and impulse control. Some psychodynamically defined character traits, particularly poor frustration tolerance, were related to symptomatic suffering.
Adult↗
Composition of mammalian eumelanins: analyses of DHICA-derived units in pigments from hair and melanoma cells.
The proportions in which two eumelanin monomers, namely 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI), compose the eumelanin polymer are believed to determine properties of the pigment including its color. These proportions are, however, not well elucidated for naturally occurring eumelanins, largely because of methodological difficulties. In this study we estimate the content of DHICA-derived units in mammalian eumelanins using a combination of two analytical techniques: 1) quantitation of DHICA-derived eumelanin by measuring the yield of pyrrole-2,3,5-tricarboxylic acid (PTCA index) and 2) spectrophotometrical quantitation of total (DHI + DHICA) eumelanin at 350 nm (A350 index). The ratio of PTCA/A350 measured for melanins synthesized from DHI and DHICA mixed in various molar proportions correlates well with the content of DHICA in synthetic polymers. Using this relationship as a standard curve we estimated the proportion of DHICA-derived units in mammalian eumelanins from hair and melanoma cells and found it to be much higher in rodent pigments (58.8%-98.3%; two species, mouse and hamster were examined) as compared to human eumelanins (19.2%-41.8%; one Caucasian and one Oriental individual were examined). No relationship between proportion of DHICA-derived units in eumelanin and hair color is found. The latter seems to be determined predominantly by the ratio of pheo- to eumelanin synthesis.
Animals↗
Mouse fibroblast expressing human tyrosinase with DHICA-oxidase activity produces predominantly pheomelanin deposit in lysosome.
The melanogenic gene-transfected cell system serves as a useful tool for the study of the symphonic relation between melanin synthesis and intracellular organelles such as melanosomes in melanocytes. We constructed melanin-producing mouse fibroblasts by transfection of human tyrosinase cDNA to investigate the intracellular changes caused by tyrosinase expression. DHICA-oxidase (5,6-dihydroxyindole-2-carboxylic acid oxidase) activity without TRP-1 (Tyrosinase Related Protein-1) expression in the cells suggested that human tyrosinase also possesses a DHICA-oxidase activities different from mouse tyrosinase. Electron microscopic observation indicated that melanin-deposit organelles have some lysosomal features. These properties of melanin-deposit organelles in tyrosinase expressing fibroblasts provide one evidence for the hypothesis that melanosome is the specialized lysosome in melanocytes.
Animals↗
Inhibitory effects of melanin monomers, dihydroxyindole-2-carboxylic acid (DHICA) and dihydroxyindole (DHI) on mammalian tyrosinase, with a special reference to the role of DHICA/DHI ratio in melanogenesis.
DOPAchrome tautomerase (DCT) is known to control the ratio of DHICA/DHI formed within the melanocyte, but physiologic significance of this activity is not yet fully elucidated. In this study the two melanin monomers are shown to inhibit with different efficacy the initial, tyrosinase-controlled, melanogenic reaction, namely conversion of L-tyrosine to DOPAchrome (2-carboxy-2,3-dihydroindole-5,6-quinone). This is demonstrated in the test tube assay system whereby formation of DOPAchrome is catalyzed by i) isolated premelanosomes (PMS), ii) tyrosinase-rich PMS glycoproteins, or iii) tyrosinase purified from fibroblasts transfected with human tyrosinase gene. Both DHI and DHICA suppress the conversion of L-tyrosine to DOPAchrome when added to reaction mixture but the inhibitory effect is far more strongly pronounced by DHI. DHI inhibits both activities of tyrosinase--tyrosine-hydroxylation and DOPA-oxidation--more strongly than DHICA. The different extent of inhibition is shown to reflect i) the ability of the two monomers to compete with tyrosinase substrates for the enzyme's active center and ii) the rate of interaction between melanin monomers and DOPAquinone. Consequently, we demonstrate that the tyrosinase-catalyzed DOPAchrome formation can be modulated by the ratio of DHICA/DHI among melanin monomers with the increased proportion of DHICA resulting in more efficient DOPAchrome formation. These results raise the possibility that DOPAchrome tautomerase plays a role in positive control of the tyrosinase-catalyzed early phase of melanogenesis.
Animals↗
Electrophoretic heterogeneity of pigmented hamster melanoma cells.
Pigmented hamster melanoma tumors growing in situ contain two subpopulations of melanoma cells that have different electrophoretic mobilities (EPM). A mild neuraminidase treatment, which removes sialic acid residues from the cell surface glycoproteins, reduces the EPM of both groups of melanoma cells yielding an electrophoretically uniform population. This shows that the differences in the EPM between the subpopulations of pigmented melanoma cells stem from the different content of sialic acid residues on the cell surface. The relationship between the different EPM melanoma cell subpopulations was, therefore, examined during tumor growth, development, and formation of metastases. The relative content of cells having high electrophoretic mobility, the "fast moving" cells, increases as the tumors grow larger. However, tumors of the same diameter contain nearly the same fraction of "fast moving" cells despite their age. The proportion of the "fast moving" cells is significantly higher in the central part than in the outermost layer of pigmented melanoma tumors. These data suggest that the development of "fast moving" cells is promoted by some size-dependent changes in the intratumor environment. In vivo selection of melanoma cells for their ability to colonize lungs renders tumors that reveal elevated metastatic potential and contain a significantly higher fraction of cells possessing high electrophoretic mobility than the parent tumor. Moreover, the metastatic nodules contain a remarkably elevated fraction of the "fast moving" cells. The reported correlation between the "fast moving" cell fraction and the metastatic potential suggests that the relative content of cells having high electrophoretic mobility may determine the metastaticity of pigmented hamster melanoma.
Animals↗
Regulatory factors for polymerization of melanin monomers within coated vesicles and premelanosomes in melanoma cells.
Coated vesicles (CV) and premelanosomes (PMS) differ in the amount of melanin monomers produced from 2-carboxy-2,3-dihydroindole-5,6-quinone (dopachrome) in vitro. CV convert dopachrome preferentially to 5,6-dihydroxy-indole-2-carboxylic acid (DHI2C) and PMS mainly to 5,6-dihydroxyindole (DHI). We examined the effect of CV and PMS on in vitro spontaneous polymerization of DHI and DHI2C. The polymerization of DHI is accelerated by addition of extracts from both CV and PMS, while polymerization of DHI2C is suppressed. Factors associated with these two regulatory activities have been separated on concanavalin A-Sepharose. The ConA-adhesive glycoproteins isolated from PMS enhance polymerization of not only DHI but also DHI2C. The latter effect is stimulated by dopa. Both accelerating activities can be inhibited by phenylthiourea (PTU). In contrast to glycoproteins, the non-glycoprotein subfraction suppresses spontaneous polymerization of both melanin monomers. Our data suggest that the absence of in vivo melanin polymer formation within CV can be explained by formation by these organelles of relatively stable DHI2C rather than easily polymerizing DHI.
Animals↗