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Biomedical subjects

V Brabec

Publications and source records attributed to V Brabec.

At least 163 records · Page 9Linked to original sources
PubMed1976

Filtrability of erythrocytes in "hypersplenic" rats.

The values of haemoglobin, reticulocytes and half-times of the filtrability of non-washed and washed erythrocytes were examined in male albino rats, Wistar strain, after i.p. injections of methylcellulose (MC) and compared with controls. In individual experiments the rats received 2 to 32 injections of MC. In injected animals, the filtrability of non-washed erythrocytes was altered. The filtrability half-times of the washed erythrocytes did not differ from the controls. Thus, the filtrability is altered for extracorpuscular reasons. "Hypersplenism" being completely developed, (after 32 MC injections), the filtrability of non-washed erythrocytes repaired when the application of MC had been discontinued, the reticulocyte values remained however increased. Problems of the mechanism of anaemia in experimental "hypersplenism" after MC injections in rats and relations between the altered filtrability of the erythrocytes and the haemolysis are discussed.

Animals↗
PubMed1975

Erythropoietin formation in rats with experimental hypersplenism.

Splenomegaly accompanied by anaemia, increased reticulocyte and decreased thrombocyte counts, was induced in Wistar rats by a long-term intraperitoneal administration of methylcellulose. Compared to controls, hypersplenic rats showed significantly enhanced utilization of 59-Fe by red cells and increased titre of erythropoietin. After the exposure of rats to hypoxic hypoxia corresponding to an altitude of 7,000 m for 6 h, no difference in the erythropoietin titre was found in either group. The results suggest that experimental hypersplenism alone does not affect the production of erythropoietin and does not stimulate the formation of an inhibitor of erythropoietin or erythropoiesis. The increased titre of erythropoietin and enhanced utilization of radioiron by red cells in rats with hypersplenism were found to be due to haemolytic anaemia leading to the stimulation of erythropoiesis.

Anemia, Hemolytic↗
PubMed1975

Blood volume changes in "hypersplenic" rats.

Blood volume in "hypersplenic" and normal rats was assessed by a simultaneous measurement of erythrocyte and plasma volumes by means of 59Fe-labelled erythrocytes and 131I-labelled human serum albumin, respectively. The "hypersplenic" condition was induced by prolonged intraperitoneal application of methylcellulose. Mean blood volume in normal rats was 6.3 ml/100 g body weight, the venous haematocrit being 48%. Mean blood volume in "hypersplenic" rats was 7.5 ml/100 g body weight, and the venous haematocrit lower by 22% than in normal animals. Compared with normal animals, the erythrocyte volume in "hypersplenic" rats was lower by 15% only. Plasma volume in "hypersplenic" rats exceeded the compensation in response to the reduction in erythrocyte mass. In addition to haemolysis, haemodilution due to plasma expansion seemed to be responsible for the anaemia in "hypersplenic" rats.

Animals↗
PubMed1975

Interaction of nucleic acids with electrically charged surfaces. VI. A comparative study on the electrochemical behaviour of native and denatured DNAs at graphite electrodes.

Adsorption and electrochemical oxidation of deoxyribonucleic acid (DNA) at a pyrolytic graphite electrode (PGE) and a paraffin wax-impregnated spectroscopic graphite electrode (WISGE) were studied using differential pulse voltammetry. DNA is adsorbed at the surface of the graphite electrodes in a broad range of potentials including the potentials of electrochemical oxidation of DNA. Both native and denatured DNAs yield two single, well-defined and separated peaks, G and A, on the differential pulse voltammograms at the PGE and WISGE. The more negative peak, G, corresponds to electrochemical oxidation of guanine residues, whereas the more positive peak, A, corresponds to electrochemical oxidation of adenine residues. Peaks G and A of native DNA occur at the same potentials as peaks G and A of denatured DNA. However, electrochemical oxidation of adenine and guanine residues at graphite electrodes is markedly suppressed in native DNA. The heights of the peaks G and A represent a sensitive indicator of the helix-coil transition of DNA. An analysis of the product of interaction of a sample of native DNA with a large pyrolytic graphite electrode in the presence of formaldehyde at approximately neutral pH did not prove changes in the secondary structure of native DNA due to its interaction with the graphite electrode. It is suggested that the decreased differential pulse-voltammetric activity of native DNA is connected with its decreased flexibility.

Journal Article↗