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Biomedical subjects

T Matsubara

Publications and source records attributed to T Matsubara.

At least 523 records · Page 29Linked to original sources
PubMed1982

[Study on tricuspid regurgitation in Ebstein's anomaly using pulsed Doppler technique combined with two-dimensional echocardiography].

To investigate the localization of tricuspid regurgitant flow in Ebstein's anomaly, pulsed Doppler echocardiography (PDE) was performed on nine patients with or without associated cardiac lesions. The equipment used was characterized by the real time frequency analysis of Doppler signals obtained from the sampling sites confirmed on the cross-sectional images. We employed the apical four-chamber view or right ventricular inflow view in order to facilitate the sampling of Doppler signals from the three-sided heart chambers of this lesion. Doppler signals were recorded from several points in the functional right ventricle, atrialized right ventricle and right atrium. The PDE recording was made in conjunction with M-mode echocardiography at a paper speed of 50 mm per second. In eight of the nine patients, a systolic disturbed flow of wide band pattern was maximally located in the atrialized right ventricle in the vicinity of the tricuspid valve leaflets and had a delayed onset, which were seemed to be the findings characteristic of tricuspid regurgitation in Ebstein's anomaly. In the remaining one, a turbulent flow due to this lesion was obscured by a systolic jet of the associated ventricular septal defect in the vicinity of the tricuspid valve leaflet. In the right atrium, no disturbed flow of wide band pattern existed or only a faint abnormal blood flow was observed during systole. In the functional right ventricle, a smooth blood flow of the right ventricular inflow was recognized in diastole. In contrast, 15 patients with secondary tricuspid regurgitation revealed a holosystolic disturbed flow of wide band pattern maximally in the right atrium in the vicinity of the tricuspid valve leaflets. In eight healthy subjects, there was no systolic disturbed flow in the right atrium. Pulsed Doppler technique combined with two-dimensional echocardiography is thought useful to detect the localization of the disturbed flow in Ebstein's anomaly, thus contributing to the differentiation of various causes of tricuspid regurgitation.

Adult↗
PubMed1981

pH-dependent interaction of microsomal cytochrome P-450 with substrates. I. Effect of pH upon the interaction of exogenous substrates with membrane-bound cytochrome P-450.

The interaction of microsomal membrane-bound cytochrome P-450 with substrates was studied spectrophotometrically at various pH-values. The binding of type I compounds, hexobarbital and androstanedione, with cytochrome P-450, as determined by the magnitude of the type I spectral change of microsomes, was markedly enhanced at alkaline pH compared to that at acid pH. The pH-dependent spectral change could be reversed by changing the pH. The maximum absorption change (delta Amax) increased with increasing the pH, while the spectral dissociation constant (Ks) decreased. A similar pH-dependent binding reaction was also observed using a non-dissociative type I compound, cyclohexane. On the contrary, the absorbance magnitude between peak and trough in the aniline- or alcohol-induced difference spectrum of microsomes was enhanced by decreasing the pH, indicating easy complex formation of type II and reverse type I compounds with cytochrome P-450 in the acid rather than the alkaline region.

Aniline Compounds↗
PubMed1981

Structural studies on glycolipid of shellfish. III. Novel glycolipids from Turbo cornutus.

Five kinds of sphingoglycolipids were isolated from Turbo cornutus. Four of them were a series of novel glycolipids consisting only of galactose. The structures of these glycolipids were studied by methylation analysis, periodate oxidation, enzymatic degradation, and proton magnetic resonance spectroscopy. Three glycolipids were characterized as galactosyl(beta 1 leads to 1)ceramide, galactosyl(beta 1 leads to 6)galactosyl(beta 1 leads to 1)ceramide, and galactosyl(beta 1 leads to 6)galactosyl(beta 1 leads to 6)galactosyl(beta 1 leads to 1)ceramide. Data indicating that the 4th glycolipid might be the tetragalactosyl derivative of this series were obtained. The carbohydrate moiety of the 5th glycolipid, in contrast, was composed of fucose, galactose, glucose and N-acetylglycosamine in a molar ratio of 1 : 2 : 1 : 1.

Carbohydrates↗
PubMed1981

Difference in fenitrothion-inhibited rat plasma cholinesterase activities determined by delta pH-method and DTNB-method, due to spontaneous reactivation.

Rat cholinesterase (ChE) activities were measured by DTNB-method after an oral administration of fenitrothion, and the following facts were observed. The inhibited plasma ChE (pseudo ChE) obtained within several hours after the administration was spontaneously reactivated at 10 degrees C or over, whereas no reactivation was observed at 1 degree C. Neither red blood cell nor brain ChE (true ChE) was spontaneously reactivated. In vitro, the spontaneous reactivation was also observed in rat plasma ChE inhibited by oxon-type of fenitrothion. In case the activity of plasma ChE obtained 30 min after administration was determined by delta pH-method, the activity was higher than the actual value, because of the spontaneous reactivation taking place during an incubation for 1 h at 37 degrees C. It is suggested from these results that an utilization of delta pH-method is unsuitable for the measurement of the activity of inhibited ChE which is spontaneously reactivated.

Animals↗
PubMed1981

Hepatic aminopyrine N-demethylase system: interaction of aminopyrine with microsomal cytochrome P-450.

Interaction of aminopyrine with microsomal membrane-bound cytochrome P-450 was studied spectrophotometrically at various pH. Aminopyrine-induced type I spectral change in untreated rat microsomes was observed in neutral and alkaline media, and the absorption magnitude between peak and trough in the spectra increased markedly by increasing pH. On the other hand, an anomalous spectral change (lambda max, 425 nm; lambda min, 410 nm) was obtained in acid medium, and the absorption magnitude of the anomalous spectral change was enhanced by decreasing pH. The spectral dissociation constant for the anomalous aminopyrine-binding reaction at pH 6.32 was about one order of magnitude greater than that for the type I binding reaction at pH 8.22. The type of aminopyrine-induced spectral change differed depending upon the age and pretreatment of animals. Neonatal microsomes elicited only the anomalous spectral change in all pH media. Liver microsomes from 3-methylcholanthrene-pretreated rats showed a reverse type I spectral change. Antipyrine produced only a reverse type I spectral change in all microsomes tested, and the absorption magnitude was enhanced by decreasing the pH. In the presence of a saturated concentration of a reverse type I compound, i.e., ethanol or antipyrine, aminopyrine induced the type I spectral change, even in acid medium. The binding mechanism of cytochrome P-450 with aminopyrine is discussed on the basis of these results.

Aminopyrine↗
PubMed1980

Purification, properties and formation of arginine-alpha-ketoglutarate transaminase in Arthrobacter simplex.

Arginine-alpha-ketoglutarate transaminase was purified 460-fold with 1.4% yield from Arthrobacter simplex grown on arginine as a carbon source. The preparation was more than 90% pure on polyacrylamide gel electrophoresis, and the molecular weight of the enzyme was calculated to be 110 000. The enzyme exhibited absorption maxima at 280, 330 and 370 nm. The 370 nm peak decreased with increase in the 330 nm peak on addition of arginine Km values for arginine, alpha-ketoglutarate, glutamate and alpha-keto-delta-guanidinovalerate were 2.9, 8.1, 25 and 0.30 mM, respectively. Those for pyridoxal 5'-phosphate and pyridoxamine 5'-phosphate were 0.25 and 0.57 microM. The enzyme reacted optimally at pH 8.0--8.5. The synthesis of arginine-alpha-ketoglutarate transaminase was inducible by arginine and alpha-keto-delta-guanidinovalerate.

Arthrobacter↗
PubMed1979

Altered bile acid metabolism in alloxan diabetic rats.

Changes of cholesterol, phospholipid, triglyceride or bile acid levels in serum liver, bile and feces after the treatment with alloxan were examined in Wistar strain male rats. Serum cholesterol, phospholipid and triglyceride levels and liver cholesterol level markedly increased but liver phospholipid and triglyceride levels remained unchanged. The lipid levels in serum very low density and low density lipoproteins were elevated but those in high density lipoprotein were not. Bile flow was not changed but biliary secretion of cholesterol, phospholipid and bile acids markedly increased. Among the biliary bile acid components, cholic acid markedly increased but the amount of chenodeoxycholic acid was similar to that of normal rats. Fecal excretion of deoxycholic acid increased but that of lithocholic and hyodeoxycholic acids decreased, and alpha, beta- and omega-muricholic acids did not change, thus, the total amount of fecal bile acids remained unchanged. Hepatic cholesterol synthesis was markedly depressed, while cholesterol 7 alpha-hydroxylase activity did not change and cytochrome P-450 content was elevated by about 40%. From such evidence, it was apparent that synthesis of cholic acid increased while that of chenodeoxycholic acid decreased and the total amount of bile acids synthesized did not change in the diabetic rats. Furthermore, marked increase of the pool size of cholic acid and hepatic secretion of cholic acid stimulated the absorption of lipids and produced a hyperlipidemia in the diabetic rats.

Alloxan↗
PubMed1978

Structural studies on glycolipid of shellfish. II. Occurrence of 3-O-methylgalactosamine in oyster glycolipid.

3-O-Methyl hexosamine was found for the first time and characterized as one of the sugar components of oyster glycolipid. The alditol acetate of this sugar was identified as 3-O-methyl-N-acetylgalactosaminitol acetate by comparing its retention time on gas chromatography and mass spectrum with those of the authentic sample synthesized in this laboratory. The new sugar, 3-O-methylgalactosamine, occupied the non-reducing terminal position of the carbohydrate moiety of the lipid and was linked to the penultimate hexose by a (1 leads to 3) bond.

Animals↗