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Biomedical subjects

M Kellermayer

Publications and source records attributed to M Kellermayer.

At least 55 records · Page 3Linked to original sources
PubMed1983

Ionic milieu and volume adjustments in detergent-extracted thymic nuclei.

Detergent-extracted isolated thymic lymphocyte nuclei were incubated in buffers containing 3 mM Ca++ and Mg++ and varying concentrations of Na+ and K+. Nuclei in 15 mM K+, 15 mM Na+ had a smaller size, smaller interchromatin spaces, and less packed chromatin than nuclei in the absence of these ions, but their water content relative to dry mass was not significantly different. NMR relaxation properties of water protons in these different nuclei were different, and nuclei in 15 mM K+, 15 mM Na+ contained twice as much K and Na as in the buffer solution. These findings indicate that the hydration of chromatin bodies and the size of the interchromatin spaces are sensitive to the free monovalent ion concentrations. When isolated nuclei were exposed to solutions containing 150 mM total concentration of K + Na, the nucleoplasm became disrupted and the hydration index was greater. The results are discussed in regard to possible mechanisms of nuclear volume control in cells.

Animals↗
PubMed1981

Low-molecular-weight zinc-binding proteins in liver cytosol of the allylisopropylacetamide (AIA) treated rats.

Rats maintained on a normal diet supplemented with 10 microCi 65Zn/day for a period of 10 days were given allylisopropylacetamide (AIA), 400 mg/kg body weight: 24 h later they were killed. Cytosol was prepared from liver cells and analysed by gel filtration on a Sephadex G-75 column. The AIA treatment caused an alteration in the chromatographic pattern of Zn-binding proteins, and a low-molecular-weight fraction appeared.

Acetamides↗
PubMed1980

ADP induced surface charge changes of adult and newborn platelets.

In experiments reported here electrophoretic mobility of washed platelets and platelets suspended in diluted plasma obtained from adults and newborns was practically the same. No significant difference was observed in the pH-mobility relationship of the two types of platelets. These comparative studies indicate that the actual charge density, i.e. the number and sign of the charged groups at the newborn and adult platelet surfaces are essentially identical. However, a significant difference was found between the two platelet populations in the mobility changes induced by ADP. On the basis of cross over experiments between the platelets and plasma of adults and newborns it seems likely that the different behaviour of neonatal platelets arises from a difference between adult and newborn plasma. Preliminary results indicate that this may be due to the presence in adult plasma of a component with molecular weight about 10 000.

Adenosine Diphosphate↗
PubMed1980

Metal content of rat liver cell organelles.

Zn2+, Fe2+, Cu2+, Ca2+, and Mg2+ were determined by means of atomic absorption techniques in tetramethylammonium hydroxide digests of cell organelles isolated from normal rat liver tissue. The metal content of the cell organelles was expressed with reference to their protein content. The results showed that digestion with tetramethy la ammonium hydroxide can be applied for the determination of metal to protein ratios in the cell organelles and that these ratios appear to be suitable for the characterization of cell organelles.

Animals↗
PubMed1980

Zn-binding protein profile of rat liver cytosol. Chromatographic and electrophoretic study.

65Zn2+ was given to rats per os and intraperitoneally for in vivo labelling of Zn2+-metalloproteins of cytosol. At the chromatographic analysis of the cytosol, two 65Zn2+-containing protein peaks were found in per os, while an additional low molecular weight third peak appeared in the intraperitoneal dosing samples. The chromatographic fractions were further separated by a non-denaturing gradient polyacrylamide electrophoresis technique. At the electrophoretic analysis of the chromatographic fractions the recovery of 65Zn2+ was the highest in samples taken from a second chromatographic peak (88%), which indicates the presence of proteins with exceptionally strong Zn2+-binding character in the 30-40 000 molecular weight fraction of the cytosol.

Animals↗
PubMed1980

Swelling of nuclei and decondensation of chromatin in a multinuclear model.

Rat liver nuclei were isolated in the presence of a nonionic detergent, and the soluble proteins were extracted from them using low-salt solution. The isolated nuclei were then embedded in a fibrin clot which was cut into 4 to 5 mm3 pieces and placed into an AMICON pressure cell in the presence and absence of the soluble nuclear proteins. When the soluble nuclear proteins were present and when their concentrations reached 40 mg/ml, the nuclei were significantly larger and their chromatin more decondensed than in the absence of added proteins. Our findings suggest that the soluble nuclear proteins play a role in the regulation of nuclear volume and the hydration of chromatin.

Animals↗
PubMed1979

Dynamic inorganic ion-protein interactions in structural organization of DNA of living cell nuclei.

Staining polarization optical techniques showed differences in the structural organization of DNA of chromatin in interphase nuclei and in mitotic chromosomes. The DNA was non-birefringent in intact interphase cell nuclei, but birefringent in chromosomes and in isolated nuclei incubated in a physiological electrolyte solution. The birefringence of DNA appears to be related to an unfolding of DNA filaments induced by free cations and to the oriented binding of dye molecules to DNA phosphates. We propose that the actual concentration of free cations inside the living cell nuclei is regulated by a dynamic interaction between nuclear proteins and ions.

Animals↗
PubMed1978

Study of DNA metabolism of lymph-node cells by direct lymphatic administration of tritiated thymidine.

A method for studying DNA metabolism in lymph-node cells by injecting tritiated thymidine intralymphatically is described. The administration of [3H]thymidine through a lymph vessel enabled a high concentration to be attained with only a small quantity of the precursor in close proximity to the cells. The significance of the method is that it may also be used in studies of metabolic processes in human lymph-nodes.

Animals↗
PubMed1978

Inhibition of internuclear transport of SV40-induced T antigen in heterokaryons.

Internuclear migration of tumour specific nuclear T antigen has been analysed in SV40-induced H-50 tumour and chick erythrocyte heterokaryons. Thirty hours after cell fusion the incorporated and enlarged erythrocyte nuclei were invariably T antigen-positive. When treated with colchicine at 10(-4) or 10(-7) M concentration, the erythrocyte nuclei incorporated into the heterokaryons did not swell and remained T antigen-negative. The results strongly suggest the involvement of a colchicine sensitive contractile protein matrix in the internuclear transport of T antigen and other proteins.

Animals↗
PubMed1978

A fluid mechanical hypothesis for macromolecular transport in living cells: I.

A fluid mechanical process generating controllable steady streaming is introduced as a model for explanation of specific molecular transport processes in living cells. Intracellular organelles, attached to contractile cytoplasmic fibrils and executing simultaneous oscillations and volume pulsations, are envisioned as the driving mechanisms for this transport system.

Biological Transport↗
PubMed1978

The amount of Zn, Fe, Cu, Mg and Ca in rat liver and their relation to cytosol proteins.

The amount of Zn, Fe, Cu, Mg and Ca in rat liver samples was analysed by atomic-absorption spectrophotometry and the association of Zn, Fe and Mg to cytosol proteins was studied by ultrafiltration. Nearly all of the Zn and Fe attached tightly to the protein molecules, while more than 30% of Mg was found to be "free" (ultrafilterable) in the cytosol.

Animals↗
PubMed1977

Effect of divalent cations on the extraction of nuclear proteins.

TSCM-(0.01 M Tris-HCl, 0.25 sucrose, 3.8 mM CaCl2, 12 mM MgCl2, pH 7.2) and TS-(0.01 M Tris-HCl, 0.25 M sucrose, pH 7.2)-soluble proteins of isolated rat liver nuclei were analyzed by a two-dimensional polyacrylamide gel electrophoresis method. Light microscopy showed that treatment with the TSCM solution did not alter the morphology of isolated nuclei. After treatment with the divalent cation-free TS solution, the isolated nuclei were swollen; some were disrupted and clumped together. The TSCM solution extracted 20 additional proteins including histones. These results suggest that Ca++ and Mg++ play an intracellular role in the interactions between nuclear proteins and chromatin.

Animals↗
PubMed1977

Sodium and potassium content of cataractous human lenses.

The sodium and potassium content of human senile cataractous lenses was investigated by flame photometry. A parallelism was found between the severity of the senile cataractous disorder and the increase of sodium and decrease of potassium content of lenses. The changes in ion concentration were not entirely continuous; gaps were found for both cations in a certain concentration range. The involvement of lens proteins in maintaining the gradients for sodium and potassium is also discussed.

Aged↗
PubMed1976

DNA synthesis in cells of human tuberculous lymph nodes.

DNA metabolism of cells of tuberculous lymph nodes was studied autoradiographically with 3H-thymidine injected directly into one of the afferent lymph vessels. The undifferentiated mononuclear cells showed the most intensive DNA synthesis, but a large number of epitheloid cells had also become labelled. The nuclei of the giant Langhans cells took no label.

Autoradiography↗