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Biomedical subjects

A Stoklasová

Publications and source records attributed to A Stoklasová.

At least 19 recordsLinked to original sources

Evaluation of the antineoplastic activity of mitoxantrone-L-carnitine combination therapy on an experimental solid form of ehrlich tumour in mice.

We have commenced a series of experiments to evaluate the effect of carnitine derivatives on the antineoplastic activity of mitoxantrone (MX) on various animal cancers. This report describes the therapeutic effect of MX in combination with l-carnitine (LCAR) on the growth of a solid form of Ehrlich tumour inoculated into mice. LCAR was administered subcutaneously at doses of either 200 or 100mgkg(-1) on day 6 and 13 after tumour inoculation, 1h prior to the treatment with MX. Mitoxantrone was administered intravenously at doses of 3 or 6mgkg(-1). We found that LCAR had no potentiating effect on the efficacy of MX, in terms of either slowing tumour growth or increasing the survival of mice. Nevertheless, therapeutic effects can be assumed at higher doses of both drugs based on values calculated from an index of relative hazards.

Algorithms↗

Reactive oxygen metabolites in inflammation.

The functions of professional phagocytes depending on oxygen are briefly discussed. After appropriate stimulation, membrane-bound enzyme systems are activated--phospholipase C, protein-kinase C and NADPH-oxidase complex--and superoxide anion is produced. This process is called respiratory burst and is essential for killing of microorganisms but it may cause tissue damage and inflammation. The influence of superoxide anion on metabolism is reviewed. More attention is paid to modulating effects of superoxide anion in connection with the development inflammatory process.

Animals↗

Soluble elastins, their preparation and characterization.

We followed amino acid composition, sugar content, immunological reactivity and thermal coacervation of elastin-derived peptides in order to show whether the preparation procedure influenced the properties. Insoluble elastin was prepared by alkaline hydrolysis (N-elastin) or cyanogen bromide cleavage (C-elastin) of bovine ligamentum nuchae. The insoluble elastins were solubilized in oxalic acid, phosphoric acid or trifluoroacetic acid. The differences in properties were found in the case of trifluoroacetic hydrolysis only in comparison with soluble elastin-derived peptides prepared by oxalic or phosphoric acids hydrolysis. Trifluoroacetic acid probably breaks down the structure markedly including the antigenic determinants, which results in a low reactivity with antibodies. The ability of these peptides to form coacervates is also decreased.

Animals↗

Superoxide dismutase activity in radioresistant tissues of irradiated rabbits.

The activities of Cu, Zn-containing superoxide dismutase were studied in radioresistant tissues (liver, brain, erythrocytes) of whole-body irradiated rabbits with 6.0 Gy and 24.0 Gy with local shielding. No significant changes were observed after irradiation with 6.0 Gy. Both the changes in Cu, Zn-SOD activity and the protein concentrations were more pronounced after exposure to 24.0 Gy with local shielding of the head and abdominal region. The dose on the shielded regions was about 6.0 Gy. Local shielding of rabbits irradiated with a lethal dose 24.0 Gy influenced positively the survival of animals. However, the decrease in SOD activity on 60th day after irradiation seems to be unfavourable for further survival of rabbits, if we accept that SOD content in tissue is maintained at a rather constant level.

Animals↗

Activity of superoxide dismutase isoenzymes in the bone marrow of irradiated rabbits.

The activities of total, Cu,Zn- and Mn-containing superoxide dismutase were studied in the bone marrow of whole-body irradiated rabbits with 6.0 Gy or 24.0 Gy with local shielding. Irradiation with 6.0 Gy depressed the activities of total and Cu,Zn-SOD on the 8th and 15th days, whereas the activity of Mn-SOD did not change. The exposure to 24.0 Gy with local shielding of head and abdominal region decreased Cu,Zn-SOD activity on the 4th and 60th days after irradiation, Mn-SOD activity was lower nearly at all time intervals investigated. The exposure to 24.0 Gy with shielding of whole body without head region increased markedly Cu,Zn-SOD activity, whereas Mn-SOD activity was diminished on the 8th and 15th days after irradiation in comparison with control group. Mn-SOD activity (U per 10(6) of bone marrow cells) was increased at early time intervals, the changes were not so striking after irradiation of rabbits with 24.0 Gy with shielding of whole body without head region.

Animals↗

[Soluble elastin and antibody formation].

In the present study, we have obtained antibodies in rabbits to peptides prepared by digestion of elastin with either oxalic acid or phosphoric acid. By Elisa assay, we have shown the lowest production of antibodies against elastin-derived peptides prepared by digestion of N-elastin with phosphoric acid. We have found a strong cross-reactivity between antibodies obtained to peptides prepared by different digestion of insoluble elastin from bovine ligamentum nuchae or aorta and these antigens. A less pronounced cross-reactivity was observed in case of elastin-derived peptides from porcine aorta.

Animals↗

Activities of blood glutathione peroxidase in schizophrenic and depressive patients.

Glutathione peroxidase activity was determined in the blood of healthy individuals and schizophrenic and depressive patients. No significant changes in enzyme activity were observed between the groups of patients. A slight decrease in glutathione peroxidase activity was found in the group of schizophrenic men and in the groups of depressive patients. The treatment with neuroleptics did not influence enzyme activity with an exception--the group of depressive men.

Adolescent↗

Erythrocyte superoxide dismutase activity in patients with pernicious anemia and chronic lymphocytic leukemia.

Superoxide dismutase activity was determined in the erythrocytes of healthy individuals and patients suffering from pernicious anemia, chronic lymphocytic leukemia and dyserythropoetic anemia type II. Enzyme activity was significantly decreased in the group of patients with chronic lymphocytic leukemia treated with cytostatic drugs. Most pronounced decreased occurred in erythrocytes of patients with dyserythropoetic anemia.

Aged↗

[The effect of a diet containing long-chain fatty acids on the formation of insoluble elastin in the rat aorta].

The paper deals with the influence of long-chain fatty acids on the formation of insoluble elastin in vivo. Oil isolated from the sea fish named flounder has been chosen as the source of those long-chain fatty acids. The diet containing the flounder oil was administered to pregnant rat females. The influence of fatty acids on the formation of insoluble elastin was evaluated according to the percentage changes of insoluble elastin in the aortas of newborn rats and to the changes of the amount of desmosine cross-links in isolated elastin. The administration of the diet with long-chain fatty acids causes no changes in the content of elastin in the aortas of the new-born rats, meanwhile the amount of desmosine increases considerably. The results on the aortas of new-born rats shown here are in good agreement with the changes on the aortas of 3-month-old rats published in a previous paper.

Animals↗

Defence against the toxic action of oxygen.

Oxygen is a Yanus-faced molecule, it conditions life but it also exerts toxic effects. In the present survey, the oxygen activation, biological effects of oxygen-derived metabolites and the possible protection of living organisms have been reviewed. Superoxide and hydroxyl radicals together with hydrogen peroxide and singlet oxygen are believed to be responsible for oxygen toxicity. It is supposed that free radical mechanism is participated in inflammatory diseases, myocardial infarction, carcinogenesis, in effect of ionizing radiation or in aging. Living organisms are equipped with a variety of antioxidant agents. There are the enzymes - superoxide dismutase that dismutases superoxide radicals to hydrogen peroxide and catalase or glutathione peroxidase that detoxify hydrogen peroxide. The low molecular substances are also involved in the protection, e. g. glutathione, ascorbate, vitamins A and E. In following part of our review the knowledge on the activities of above mentioned enzymes under pathological conditions has been reported. The attention is directed to inflammation, hemolytic states, neurologic and psychiatric disorders, carcinogenesis, the effect of ionizing radiation, aging, autoimmune disease and hypoxia-reperfusion injury.

Animals↗

Superoxide dismutase levels in various radioresistant and radiosensitive tissues of irradiated rats.

The activity of superoxide dismutase (E.C. 1.15.1.1; SOD) was determined in male Wistar rats in order to evaluate the possible relationship between both the enzyme content in tissue and the resistance of this tissue to ionizing radiation (8,0 Gy, 60Co). Our results showed that some non-irradiated radioresistant organs (liver) had a high SOD activity and on the contrary, in some radiosensitive tissue (bone marrow) the SOD content was low. In spite of this observation it is not possible to generalize the statement that the radiosensitivity is directly conditioned by the SOD level without any exception. The SOD content in the spleen was higher than in the brain, but the spleen is remarkably radiosensitive, whereas the brain is not. The radiosensitivity of individual tissues probably reflected the changes of SOD activity after the irradiation.

Animals↗