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Biomedical subjects

M Katoh

Publications and source records attributed to M Katoh.

At least 379 records · Page 21Linked to original sources
PubMed1982

Neural pathway involved in the excitation of motoneurones to jaw-opening muscles by stimulation of the orbital cerebral cortex in the cat.

The pathway and synaptic basis for the efferent discharge in the digastric nerve evoked by stimulation of the orbital cortex were studied in cats anesthetized with alpha-chloralose. Transection of the brain stem at the boundary between the pons and the medulla oblongata abolished discharge. Intracellular recording from anterior digastric motoneurones revealed that the orbital cortical stimulation evoked excitatory post-synaptic potentials with a latency that was longer by one synaptic delay than that of spike potentials evoked in medial bulbar reticular neurones making a direct excitatory projection to anterior digastric motoneurones. It was concluded that the excitatory effects was mediated by the medial bulbar reticular formation.

Animals↗
PubMed1982

Effect of malotilate (diisopropyl 1,3-dithiol-2-ylidenemalonate) on the protein synthesis in rat liver.

The effect of malotilate (diisopropyl 1,3-dithiol-2-ylidenemalonate) on the protein synthesis in rat liver was studied in vivo and in vitro. Oral administration of malotilate to rats caused an increase in the protein and RNA contents of the liver and lef to an acceleration of 14C-leucine incorporation into microsomal and cytosol proteins. In a cell-free system, the protein synthesis was enhanced by treatment with malotilate, and an unknown factor(s) which participates in the protein synthesis was found in the cytosol fraction prepared from malotilate treated livers. These results suggest that malotilate is a new type of inducer for protein synthesis. On the basis of the observations obtained in the present study, a hypothesis can be formulated that malotilate enhances liver protein synthesis by accelerating RNA synthesis and/or increasing the transport of RNA from nuclei to cytosol in rat liver.

Animals↗
PubMed1982

[Effect of malotilate (diisopropyl 1,3-dithiol-2-ylidenemalonate) on the synthesis and movement of RNA in rat liver (author's transl)].

The effects of malotilate (diisoporpyl 1,3-dithiol-2-ylidenemalonate) on the synthesis and movement of RNA in rat liver were studied in order to elucidate the mechanism of protein synthesis induced by this drug. Incorporation of 3H-cytidine into various RNAs was followed to determine the rates of their synthesis. Oral administration of malotilate to rats enhanced the total RNA synthesis, which reached to maximum level 3 hr after administration. At that time, the increases in the incorporation of radioactivities into the total RNA and the nucleotide pool were closely related to the dosages. Malotilate significantly increased the polyribosomal and t-RNA synthesis as well as nuclear RNA, but not the movement of RNA from the nuclei to the cytosol. It is not likely that malotilate activates specific genes in chromatin because only about 0.1 nmole of malotilate and its metabolites per mg DNA was found in chromatin. From these results, a possible mechanism of protein synthesis induced by malotilate can be proposed as follows: malotilate primarily affects the post-transcription process, promoting the RNA synthesis in the nuclear fraction without any changes of DNA synthesis, and these consequent increases of the polyribosomal RNA and t-RNA synthesis result in the enhancement of protein synthesis.

Animals↗
PubMed1982

[Effects of intravenous infusion of amikacin. Intraperitoneal administration to rats before and in the early stage of pregnancy. Segment 1].

Fertility study on amikacin sulfate (AMK) was carried out in Wistar rats. AMK was administered intraperitoneally at the doses of 0, 25, 100 mg/kg/day and 200 mg/kg/day in males for 60 days prior to mating and mating period and in females for 14 days prior to mating, mating period and day 0-7 of gestation. The drug induced no significant changes or signs in parent animals, except that soft feces was occasionally found at the 100 mg/kg/day and 200 mg/kg/day and the impairment in kidneys was recognized only at the 200 mg/kg/day. There were no adverse effects on mating, fertility or reproduction indices in males and females. And there were no evidences of teratogenic or embryotoxic effects in at any doses of AMK.

Amikacin↗
PubMed1982

[Effect of malotilate (diisopropyl 1, 3-dithiol-2-ylidenemalonate) on chronic liver injury caused by carbon tetrachloride].

Effect of malotilate on chronic liver injury induced by carbon tetrachloride (CCl4) was studied in rats. Rats were intraperitoneally injected with CCl4 dissolved in olive oil at a rate of 0.5 ml/kg, twice a week for 10 weeks. Malotilate mixed with a laboratory chow diet at a concentration of 0.2% was fed to the rats for 10 weeks, the increases of liver triglycerides (TG), malonedialdehyde (MA), and 4-hydroxyproline contents, and decrease of liver protein content were observed at 5, 8, and 10 weeks after initiation of CCl4-injection. In the histopathological study, vacuolation at 5 weeks, vacuolation and fibrosis at 8 weeks, and extreme fibrosis at 10 weeks were observed in rat liver with CCl4-injection. In the rats fed the diet containing malotilate for 10 weeks, these changes of biochemical parameters and histopathological findings were not observed at any time and only slight increase of liver TG and slight vacuolation at 10 weeks was observed. When rats were fed the diet containing malotilate for the last 5 or 2 weeks, these changes of biochemical parameters and histopathological findings caused by CCl4 were improved thereafter. Although the covalent bindings of the radioactivity from 14CCl4 to liver microsomal phospholipids were slightly depressed by malotilate feeding, it is difficult to explain the protective effect of malotilate on the liver injury only by this phenomenon. Other probable mechanisms for this effect were discussed.

Animals↗