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Biomedical subjects

M Munakata

Publications and source records attributed to M Munakata.

232 records · Page 13Linked to original sources
PubMed1982

Relationship between enhancement of morphine analgesia and inhibition of enkephalinase by 2S, 3R 3-amino-2-hydroxy-4-phenylbutanoic acid derivatives.

The effects of nineteen AHPA* derivatives were examined on morphine analgesia by tail-flick test in rats and on enkephalinase inhibition which was based on the formation of tyrosyl-glycyl-glycine from met-enkephalin. The correlation between the enhancement of morphine analgesia in vivo and enkephalinase inhibition in vitro was analyzed. The different analogs varied considerably in the degree of enhancement of morphine analgesia and inhibition of enkephalinase. A close relationship between enkephalinase inhibition expressed by IC50 in vitro and enhancement of morphine analgesia in vivo was observed in thirteen out of nineteen AHPA derivatives examined. One of other six AHPA derivatives which showed weak effectiveness in potentiating on morphine analgesia but was highly potent as an enkephalinase inhibitor, caused potent analgesic action when it was applied intracisternally indicating poor penetration of the blood brain barrier. The possibility was discussed that some of other compounds excluded from the linear relationship might act on other enkephalin degrading enzymes such as aminopeptidase.

Aminopeptidases↗
PubMed1982

Is the oxygen atom of carbon monoxide coordinated to the copper of hemocyanin?

The carbon monoxide binding site of hemocyanins was studied by comparing the isotope shift of the CO-stretching frequencies in CO-hemocyanins with that of carbon monoxide diethylenetriaminecopper(I)tetraphenylboron in which the carbon atom of CO is coordinated to the copper. Coordination by the carbon atom of CO-hemocyanin is suggested.

Animals↗
PubMed1982

[Measurement of V/Q distribution by inert gas elimination method].

Wagner & West (1974) developed the new method for determination of ventilation-perfusion ratio (V/Q) distribution of the lung using multiple inert gases and multicompartmental computer analyses (inert gas elimination method), and attracted attention of researchers of pulmonary diseases. But there are some unsolved problems in this method, and its physiological value has not been completely determined. In this study, I evaluated mathematical methods and computer algorithm precisely and determined its limits on the clinical application by showing pattern reforming abilities using error-free data. Then I measured V/Q distributions of normal mongrel dogs and dogs with pulmonary fibrosis due to paraquat poisoning. 1). Pattern Reforming Error-free data were obtained by calculation based on some mathematical functions showing various distribution patterns. Using these error-free data, reforming abilities were examined. Unimodal and bimodal distributions were recovered well but trimodal ones were not recovered satisfactorily. 2). Appropriate Value of Smoothing Coefficient, Z With the changes of Z value (0.05-999), reforming patterns changed. When Z value was about 40, the recovered pattern was most similar to the original one. 3). Gas-chromatographic Analyses of Multiple Inert Gases In order to stabilize the baseline and to make the calculation more accurate, I changed the column packing from Porapak -K to Porapak -Q and calculated the peak areas. By these minor changes, more stable analytic values were obtained. 4). V/Q Distribution of Normal Mongrel Dogs 17 normal mongrel dogs were examined and 6 of them were proved normal by autopsy. They showed nearly log normal distribution pattern with mean V/Q of 0.5-1.0. Some of these dogs also showed faint blood flow to very low V/Q areas (V/Q less than 0.1), and very high V/Q areas (V/Q greater than 10.0). 5). V/Q Distribution of mongrel Dogs with Pulmonary Fibrosis Experimental models of pulmonary fibrosis were made by giving paraquat orally to the dogs. V/Q distributions were measured in 2 of pathologically proved fibrosis dogs. They characteristically showed increased blood flow to the low V/Q areas (V/Q less than 0.1) (about 10% of total blood flow).

Animals↗
PubMed1981

[Changes of oxytocin, progesterone, estradiol and CAP around the labor by prostaglandin F2 alpha (author's transl)].

In order to elucidate the mechanism of prostaglandin F2 alpha (PGF2 alpha) action to onset of labor, the author observed the changes in maternal peripheral plasma oxytocin, progesterone, estradiol and cystine-aminopeptidase (CAP) activity around the onset of labor by PGF2 alpha. For the investigation, 66 normal pregnant women from 6 to 10 gestational months and same numbers from 39 to 41 gestational weeks were chosen. The blood samples for the latter were drawn just before drip infusion of PGF2 alpha, 5-minutes interval, 3-minutes interval of pain and just after labor. PGF2 alpha administered for labor induction intravenously, and 55 pregnant delivered. 1) The maternal peripheral mean plasma concentrations of them showed increase during pregnancy. There were positive correlations between oxytocin and progesterone, estradiol, CAP. 2) During labor, oxytocin levels increased significantly (p less than 0.01) and progesterone levels decreased significantly (p less than 0.01). On the other hand estradiol levels did not change significantly. CAP levels showed irregular changes. Estradiol-progesterone ratio showed gradual increase. 3) Then during labor, progesterone levels showed negative correlation with oxytocin levels. From this study, the results indicate that significant changes in oxytocin and progesterone and gradual increase estradiol-progesterone ratio are concerned in the onset of labor caused by PGF2 alpha, so labor may progress dynamically.

Aminopeptidases↗
PubMed1976

The role of metal ions in the activation of arginase.

The role of metal ions as activators of arginase hydrolyzing arginine were studied. The metal ion is assumed to form a complex with arginine and to promote the enzymatic reaction. The activating ability of the metal ion appears to be governed by the chelating ability and/or the coordination numbers which determine whether the metal ion combines with the enzyme or the substrate (or both substrate and enzyme) and factors which influence the configuration of the resulting complexes.

Animals↗
PubMedDate not supplied

Myocardial metastasis from primary lung cancer: myocardial infarction-like ECG changes and pathologic findings.

Myocardial metastasis from neoplastic disease is often clinically unapparent, and very difficult to diagnose. Of 151 consecutive autopsies of lung cancer patients, cardiac metastases were found in 67 patients (44.4%). Myocardial metastasis was found in only 8 patients (11.9%). ECG of patients with myocardial metastasis revealed ST-T wave changes and various types of arrhythmia. ST-T wave changes were observed in 4 with myocardial metastasis, and in 6 without myocardial metastasis (pericardial metastasis alone). ST-T wave changes is not a specific finding of myocardial metastasis. Two very rare cases with myocardial metastasis showing progressive ST segment elevation with a QS pattern are presented. The appearance of ST segment elevation with a QS pattern in clinically stable lung cancer patients without cardiac symptoms suggestive of myocardial injury indicates the possibility of myocardial metastasis. Myocardial metastasis is often elusive, thus careful observation of ECG changes is of primary importance for the antemortem diagnosis.

Adenocarcinoma↗
PubMedDate not supplied

Purification and characterization of ouabain-binding protein in human plasma.

Ouabainlike factors are thought to be a kind of important modulators of salt and water metabolism in essential hypertension. We purified the binding-protein of ouabain (OBP) from human plasma. The amino-terminal sequence of OBP from human plasma, (NH2-TLGQPREPQVYTLPPXREEM-), indicated that OBP is the carboxy-terminal fragment (14.4 kDa by SDS-PAGE) from T218 of IgG2 heavy chain and from A221 of the IgG1 heavy chain constant region. Moreover, plasmin-cleaved Fc fragment (pFc) of IgG possessed the ouabain-binding activity by the gel-filtration method of pFc and authentic ouabain mixture, whereas neither intact, aggregate, nor papain-cleaved Fc fragment did. The amino-terminal sequence of pFc was NH2-THTXPPXPAPELLGGPXVFL-, and this sequence corresponded to the T105 to L125 fragment of the IgG1 heavy chain constant region. The growth of cultured THP-1 cells were arrested in the dose-dependent manner by ouabain, which was inhibited by the addition of 20 microg/mL of pFc. These results suggested that plasmin-cleaved Fc of human IgG is one of the binding protein of ouabain/ouabainlike factor(s) in human plasma.

Cell Division↗