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Biomedical subjects

Y Mishima

Publications and source records attributed to Y Mishima.

At least 343 records · Page 19Linked to original sources
PubMed1979

Measurement of local blood flow of the intestine by hydrogen clearance method; experimental study.

Local blood flow of the bowel wall was measured by hydrogen clearance method both in the muscular and submucosal layers in the mongrel dog, separately and concurrently. A platinum wire electrode with a bare tip of 0.5 mm in length and 0.2 mm in diameter was inserted into the each layer. About 10 per cent hydrogen gas was inhalated directly through the side hole attached to the endotracheal tube for 1-2 minutes and the obtained clearance curves were plotted on the semi-logarithmic scale, which was almost monoexponential. The results obtained were as follows: 1) Mean basal perfusion rate of the muscular layer of the intestine was 0.81-0.92 ml/min/gm, whereas that of the submucosal layer was 1.29-1.31 ml/min/gm, respectively. There was little difference of perfusion rates between the small and the large intestine. The results showed good correlationship with those reported by other authors. 2) The effect of vasoactive substances such as vasoconstrictor and vasodilator on the local blood flow in the bowel wall was confirmed. 3) This method is repeatedly applicable for measurement and also renders the information on the distribution of blood flow in the splanchnic area.

Animals↗
PubMed1979

Cumulative effect of surfactants on cutaneous horny layers: lysosome labilizing action.

In order to analyze the role of various surfactants in the abnormal desquamation process of the epidermis in keratodermia type hand dermatitis, the lysosome labilizing effect of surfactants has been investigated by measuring the release of enzymes from lysosomes in vitro using spectrophotometric and gel chromatographic techniques. It has been found that the labilizing effect of surfactants decreases in the order of cationic, anionic, and nonionic surfactants and varies with its alkyl chain length. The relationship of the labilization and skin roughness inducing effect is also discussed.

Acid Phosphatase↗
PubMed1979

Cumulative effect of surfactants on cutaneous horny layers: adsorption onto human keratin layers in vivo.

An attempt has been made to determine the adsorption ability of surfactants by the human horny layers in vivo. For this purpose, a technique utilizing an acidic dye such as indigo carmine was applicable and convenient. Our in vivo study estimating adsorbing residual amounts of surfactants has revealed that there is a positive correlation between adsorbing and roughening effects. It is suggested that the pathogenesis of hand roughness is primarily related to the cumulative injury of the stratum corenum by adsorbing residual surfactant molecules.

Detergents↗
PubMed1979

The mechanism of decrease in nucleolar RNA synthesis by protein synthesis inhibition.

When protein biosynthesis is inhibited by either cycloheximide of puromycine, the nucleolar RNA synthesis of Ehrlich ascites tumor cells decreases by approximately 70% within 1 h, while the removal of these protein synthesis inhibitors causes a rapid recovery of nucleolar RNA synthesis, largely within 1 h. A similar pattern of decrease and recovery of endogenous RNA polymerase activity in isolated nucleoli or in nuclei (in the presence of alpha-amanitin) may be demonstrated after addition and removal of these drugs. Analysis of the molecular species of RNA polymerase I on a phosphocellulose column indicates that only the IB form of the enzyme decreases in the nucleoli of drug-treated cells and recovers quickly after resumption of protein synthesis. The finding that the activity of the IB form enzyme remains unchanged in the whole nuclei indicates that during cessation of protein synthesis RNA polymerase IB is either released from the nucleoli into the extranucleolar compartment or becomes so loosely bound to the nucleoli that it is leached out from the nucleoli during their isolation. By using a system of assaying free, nucleolar-template bound and total RNA polymerase I activities, data supporting the above interpretation have been obtained. Namely, in isolated nuclei free enzyme activity increases with a concomitant decrease in bound enzyme activity during protein synthesis inhibition, while the total enzyme activity remains unchanged. In isolated nucleoli, both total and bound enzyme activities decreases on protein synthesis inhibition but recover quickly on its resumption. The putative bound enzyme, fractionated with the aid of actinomycin D, is exclusively IB form, whereas the unbound enzyme consists of both IA and IB forms as previously demonstrated (1). No conversion of IB form polymerase to IA form was noted on prolonged sonication in our system. The levels of ATP and GTP in the cell did not change appreciably either during cessation or resumption of protein synthesis in these cells. The data support the previous conclusion that some short-lived protein(s) is required to maintain the normal level of ribosomal RNA transcription (2) and further suggest that the protein is required to facilitate reinitiation of the transcription by RNA polymerase IB in the nucleolus.

Adenosine Triphosphate↗