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Biomedical subjects

K Jobst

Publications and source records attributed to K Jobst.

At least 73 records · Page 4Linked to original sources
PubMed1979

Postnatal development of renal sodium handling in premature infants.

To estimate the contribution of the specific defect in proximal and distal tubular reabsorption of sodium to renal salt wasting, fractional sodium excretion, distal tubular sodium delivery, and distal tubular sodium reabsorption were determined in 11 healthy premature infants. The study was performed on the seventh day and at weekly intervals thereafter up to the sixth week of life. Sodium clearance and fractional sodium excretion decreased significantly with increasing postnatal age (P less than 0.001). There was no significant alteration in either osmolar or free-water clearances. Distal tubular sodium delivery steadily decreased from 4.96 +/- 0.66 (mean +/- SE) in the first week to 3.3 +/- 0.41 ml/minute/dl GFR in the sixth week of life (P less than 0.05). Distal tubular sodium reabsorption was 69.5 +/- 2.36% in the first week, then rose significantly to reach a value of 83.7 +/- 1.85% in the second week (P less than 0.001) and remained practically unchanged thereafter. It is suggested that the rapid improvement of distal tubular sodium reabsorption in premature infants might result from forced stimulation by the excessively activated renin-angiotensin-aldosterone system.

Age Factors↗
PubMed1979

Electrokinetic behaviour of cord blood platelets in acidosis: an in vitro study.

The effect of acidosis on platelet surface potential was studied in vitro in samples obtained from newborn infants. It was found that acidosis induced by CO2 and lactic acid decreased the electrophoretic mobility of platelets in the presence of plasma. It is suggested that the changed electrokinetic properties of platelets in acidosis may be an additional factor contributing to bleeding manifestations and thrombotic complications often seen in babies with perinatal asphyxia.

Acidosis↗
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

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 lanthanum ion on platelet electrophoretic mobility.

The effect of trivalent La ions on the elctrophoretic mobility of washed human platelets has been studied. The mobility of the human platelet in 0.145 M sodium chloride at pH 7.2 was -0.84 +/- 0.06 micron per sec per volt per cm with an isoelectric point approximately at pH 3.4 La3+ at a concentration corresponding to the physiological level of Ca2+ changed the sign of the electrophoretic mobility of the platelets at pH 5.5 and pH 4.0, but had only a faint or practically no effect at pH 3.0 and pH 2.0. It is assumed that La 3+ exerts its effect when bound to the phosphate groups on the surface.

Animals↗
PubMed1977

Infrared spectrometric analysis of urinary calculi.

The composition of urinary calculi was studied by means of infrared spectroscopy. Analysis of 150 calculi has shown that their infrared spectrum offers quick and reliable results and the method helps to plan the therapy. Organization of a central laboratory for calculus analysis is recommended.

Apatites↗
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↗
PubMed1976

Lanthanum Trichloride induced blood coagulation defect and liver injury.

The rare earth metals have anticoagulant and hepatotoxic effects, among others. In view of the connection between liver and blood coagulation, the character of the coagulation defect developing in rabbits treated with lanthanum trichloride (La) was studied and in connection with it, the role of the liver injury described earlier. The results showed the effect to depend primarily on the dose of the drug administered; acute and prolonged treatments produce coagulation defects different in type. The effect of a single large dose is characterized by a severe disturbance of thrombin formation: Prothrombin activity is decreased, PTT is prolonged, native blood does not coagulate but may be coagulated with thrombin, and its fibrinogen content is high. The effect cannot be regarded as a result of the liver injury. On giving La in repeated smaller doses, a disturbance of intrinsic thromboplastin (or thrombin) formation develops, as indicated by a decrease in prothrombin consumption. This might be due to an alteration of some serum factor or of the thrombocyte lipid factor (factor 3) and is probably connected with the liver injury.

Animals↗
PubMed1976

An extended protein coat of some cells in tissue cultures.

A proteinlike substance attached to the surface of separate or marginal cells in coverslip cultures (HeLa, HEp2, RK, M7) has been found by interference and also light microscopy after Fast-green staining. The size, concentration and refractive index of this cell coating, for which the authors have suggested the term "extended cell coat", were measured. Its possible role in the regulation of cell growth and a broader interpretation of the cell border are also discussed.

Animals↗
PubMed1975

Cytoplasmic protein network in HeLa cells.

Monolayer HeLa culture nuclei isolated in situ with nonionic detergents remained attached to the glass as a "nuclear monolayer". Searching for nuclear fixing structures a fine continuous protein network was revealed around the isolated nuclei with fluorescence microscope after acridine orange staining.

Cell Nucleus↗
PubMed1975

Electrophoretic mobility of the fetal red blood cell.

The electrophoretic mobilities of fetal and adult red blood cells have been examined. The mean mobility values for intact fetal and adult erythrocytes were the same, and there was no difference in mobility between the fetal and adult red blood cells treated with neuraminidase. However, a significant difference was observed after trypsin digestion. This may be due to a difference in composition between the fetal and adult red cell membranes.

Adult↗