Search PubMed⌕ Search

Biomedical subjects

L Benes

Publications and source records attributed to L Benes.

At least 91 records · Page 5Linked to original sources
PubMed1982

Role of Ca2+ in non-cholinergic, non-adrenergic responses to nerve stimulation of the guinea-pig small intestine.

The effects of calcium channel blockers (D-600, verapamil), sodium nitroprusside, papaverine, indomethacin, local anaesthetics and blockade of sodium pump activity on the non-cholinergic, non-adrenergic transmission in the guinea-pig duodenum, jejunum, proximal and terminal ileum were analysed in the presence of atropine and guanethidine. A decrease of the extracellular Ca2+ concentration inhibited the primary and rebound contractions but only in Ca2+ -free solution was the primary relaxation diminished. D-600, verapamil, sodium nitroprusside and papaverine inhibited both the primary and rebound contractions to the same degree and their effects on the primary relaxation were less pronounced than on the contractions. Indomethacin dissolved in alkaline solution did not depress the non-cholinergic, non-adrenergic responses in any region of the small intestine, whereas indomethacin dissolved in ethanol antagonized both the primary and rebound contractions in the muscles. Local anaesthetics (procaine, trimecaine) in low concentrations inhibited only the primary contraction. Higher concentrations also inhibited both the rebound contraction and primary relaxation. Procaine in low concentrations did not markedly affect the non-cholinergic, non-adrenergic i.j.p.s and e.j.p.s, but did block the action potentials induced by e.j.p.s. Our findings indicate that the primary relaxation, and primary and rebound contractions are probably induced by different mechanisms and are not mediated by ATP. We confirmed that prostaglandins did not participate in the generation of the rebound contraction.

Adenosine Triphosphate↗
PubMed1982

Inhibition of entry into S phase and DNA synthesis in bone marrow cells of mice by repeated injections of gentamycin.

The effect of gentamycin on bone marrow cells in unirradiated and irradiated mice was investigated by 3H-dTh incorporation into DNA using microautoradiography. Gentamycin was injected in vivo at 20 mg base/kg body weight at 8-h intervals during three days. In mice exposed to 4.78 Gy the injections of gentamycin were started on the 7th day after irradiation. In granulopoietic and erythropoietic cells the inhibition of entry of cells into S phase and the retardation of DNA replication was about 20%. The roughly 30% inhibition of entry of cells into S phase observed when the bone marrow cell population has been evaluated as a whole is discussed in terms of increased sensitivity of the young blast-like cells.

Animals↗
PubMed1981

The effect of new local anaesthetics on tracheal and anococcygeal smooth muscle.

The effects of pentacaine and heptacaine were compared with that of procaine on the isolated tracheal smooth muscle of guinea-pigs and anococcygeal muscle of rats. Pentacaine increased the initial tone of the tracheal smooth muscle. In higher concentration however pentacaine and heptacaine induced smooth muscle relaxation. Pentacaine diminished the action of histamine on the tracheal smooth muscle and both pentacaine and heptacaine depressed the effects of noradrenaline and acetylcholine on anococcygeal muscle.

Anal Canal↗
PubMed1980

Chloramphenicol toxicity in radiation disease.

The effect of chloramphenicol given in high therapeutic doses, in the course of postirradiation syndrome in irradiated mice of C57Bl/10 strain, is reported. Chloramphenicol treatment increased postirradiation mortality of animals and intensified suppression of the proliferating and differentiating processes in hemopoietic organs of the irradiated animals. The results support the assumption that postirradiation depression of hemopoiesis is a contraindication to the therapeutic employment of this antibiotic.

Animals↗
PubMed1980

The effect of carbanilic acid derivatives with local anaesthetic action on concanavalin A-induced blastic transformation of lymphocytes.

We have examined the effect of six carbanilic acid derivatives (differing in the substitution of the aromatic ring, in the coupling chain or the basic moiety of the molecule) and trimecaine, i.e. agents with local anaesthetic action, on concanavalin A-induced blastic transformation of lymphocytes. We have found that these compounds differ in the ability to block blastic transformation and agglutination of lymphocytes when added to cell cultures at different concentrations simultaneously with Con A. At the minimal inhibitory concentrations, the derivatives exhibit a different degree of toxicity which, however, provides no explanation for the inhibitory effect of most of the compounds. The known effect of these compounds on the membranes together with observed inhibition of agglutination (a relatively early sign of activation), and their lower inhibitory activity, when added several hours after Con A, support the idea that they affect the early cell membrane-mediated processes during blastic transformation. In agreement with this finding is also the observed correlation between local anaesthetic activity and the ability of individual carbanilic acid derivatives to block the blastic transformation.

Agglutination↗
PubMed1980

Inhibition of bone marrow cell proliferation and DNA replication induced by chloramphenicol.

The effect of CAP on proliferations of bone marow cells from unirradiated and irradiated (4.78 Gy) C57BL/10 mice was investigated by 3H-dTh incorporation into DNA of individual cells using autoradiography. CAP was administered from day 7 to day 10 after irradiation. CAP decreases the rate of entry of cells into S phase and the rate of 3H-dTh incorporation into DNA during replication. Cells of the erythropoietic series are mainly involved in this decrease. CAP has roughly the same inhibitory effect on unirradiated and irradiated cell populations.

Animals↗
PubMed1977

Grain distribution in autoradiograms of nuclei of synchronized HeLa cells continuously labelled with 3H-thymidine.

Changes in distribution of silver grains were evaluated in autoradiograms of nuclei of synchronized HeLa cells that were continuously labelled with 3H-TdR. Synchronization was achieved by repeated blocking with cold thymidine. Three patterns of grain distribution were distinguished: uniform, non-uniform, and a special case of non-uniform distribution, the S.C. clustering. The kinetics of changes in the proportion of individual types of grain distribution indicate that uniform and non-uniform distribution patterns result from 3H-TdR incorporation into DNA replicating during the entire S-phase, whereas DNA responsible for clustered grain distribution takes up 3H-TdR only during the second half of the S-phase. The rate of the increase in grain counts per nucleus of labelled cell and the kinetics of the exhaustion of radioactive precursor from the culture medium suggest that replication of DNA in DNA in the S-phase is not merely a linear function of time.

Autoradiography↗