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Biomedical subjects

M Tanabe

Publications and source records attributed to M Tanabe.

At least 379 records · Page 21Linked to original sources
PubMed1980

Pathophysiological significance of coronary collaterals for preservation of the myocardium during coronary occlusion and reperfusion in anaesthetised dogs.

The significance of pre-existing coronary collaterals for preservation of the myocardium during coronary occlusion and reperfusion was studied in anaesthetised open-chest dogs. The extent of myocardial ischaemic damage was assessed by the accumulation of calcium in the central zone of the ischaemic area and the size of myocardial infarct by the p-nitroblue tetrazolium staining method. Myocardial creatine kinase release was considered as an index reflecting both the extent of ischaemic myocardial damage and the size of the infarct. Reperfusion with the arterial blood of a main branch of the left coronary artery following the 60 min occlusion aggravated the ischaemic myocardial damage, as evidenced by exaggerated cardiac irregularity, myocardial calcium accumulation, and creatine kinase release. The myocardial calcium content and the logarithm of the creatine kinase release during reperfusion were linearly related to the infarct size. These parameters of myocardial damage were inversely related to the retrograde blood flow through the peripheral end of the occluded artery or the ratio of the retrograde-to-orthograde flow, indicating that the pre-existing collaterals influence preservation of the ischaemic myocardium. Thus, it is suggested that the collateral flow available during an ischaemic episode determines the viability of the myocardial cells during ischaemia, and in turn during reperfusion.

Animals↗
PubMed1980

Lethal effect of aclacinomycin A on cultured mouse L cells.

The effect of aclacinomycin A on the survival of cultured mouse L cells was studied. The drug showed a characteristic dose-survival response, i.e., an initial exponential responses followed by a sigmoidal inactivation characterized by a broad shoulder. With prolongation of the exposure time, the exponential response seen at a low concentration was remarkably intensified with a progressive decrease of the shoulder width. Two-dose fractional survival studies revealed that at least a portion of the shoulder region relation to an accumulation of sublethal damage which can be repaired during 12 hr after the first dose. The implication of these results for therapeutic scheduling is discussed.

Aclarubicin↗
PubMed1979

Enhancement of mammalian cell killing by 5-fluorouracil in combination with X-rays.

The enhanced cytocidal effect of a combination of X-rays and 5-fluorouracil was investigated by means of colony-forming ability in mouse L-cells. Cells were treated with 5-fluorouracil immediately preceding (preirradiation treatment) or following (postirradiation treatment) irradiation. In either pre- or postirradiation treatment with various concentrations of the drug for a fixed time, the enhanced effect was augmented with increasing concentrations of 5-fluorouracil up to 20 microgram/ml. When cells were subjected to postirradiation treatment with a fixed concentration of drug for varying times, the cytocidal effect was further enhanced with increasing duration of drug treatment. In preirradiation treatment, however, drug treatment for longer than 3 hr did not exhibit any further enhancement. Postirradiation treatment with 5-fluorouracil to synchronous cells at various ages demonstrated enhancement at all ages during the cell cycle. The greatest enhancement was observed in the DNA-synthetic phase. Postirradiation treatment with 5-fluorouracil (2.5 microgram/ml) for 24 hr markedly reduced the width of the shoulder of the X-ray survival curve without significantly altering the slope of the exponential portion of the curve. Recovery from sublethal radiation damage was not suppressed by 5-fluorouracil when cells were treated with drug between fractionated X-ray doses. These results indicate that damages caused by 5-fluorouracil and X-rays interact additively to induce cell killing.

Animals↗
PubMed1978

Arytenoid adduction for unilateral vocal cord paralysis.

The arytenoid adduction technique was devised and performed under local anesthesia on five patients with unilateral vocal cord paralysis. It is especially indicated for the case of a wide, glottal chink and a difference in the level of the two cords. The muscle process is pulled by two 3-0 nylon sutures in simulation of the functions of the lateral cricoarytenoid muscle and the lateral thyroarytenoid muscle. Improvement of voice after surgery was dramatic in all of the patients who were operated on. The surgical procedure is rather simple, easy, and allows adjustment of the degree of arytenoid adduction during surgery to produce the best voice obtainable.

Humans↗