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Biomedical subjects

N Sakurai

Publications and source records attributed to N Sakurai.

At least 181 records · Page 10Linked to original sources
PubMed1983

[Functional tricuspid regurgitation and its relation to the morphology of the tricuspid valve and annulus: pulsed doppler echocardiography and two-dimensional echocardiography].

The mechanism for the development of functional tricuspid regurgitation (TR) was studied by an ultrasonic method. Thirty-five examinations were performed in 31 patients who were expected to have functional TR, and the severity was classified into 4 grades according to the extension of the regurgitant signals by pulsed Doppler echocardiography. The satisfactory horizontal section of the tricuspid valve was obtained by two-dimensional echocardiography (2DE) to measure the tricuspid annular diameter and to observe systolic configuration of the tricuspid valve in 22 examinations. The tricuspid annular diameter was well correlated with the severity of TR, and "lack of coaptation" of the valve was recognized on 2DE in some cases of severe TR with the markedly dilated annulus, indicating that this dilatation was an important trigger of functional TR. Additionally, in the majority of patients with severe TR, "anterior displacement" of the tips of tricuspid leaflet(s) (6 mm or more from the tricuspid annulus towards the right ventricle) was observed, which was thought to be due to the chordal traction secondary to the right ventricular dilatation, and contributed to the development of functional TR by disturbing sufficient coaptation. In one particular case, severe TR was associated with " malaligned coaptation" caused by the anterior displacement confined to the septal leaflet, indicating that asymmetrical dilatation of the right ventricle and/or disorientation of chordae-valve system may contribute to TR.(ABSTRACT TRUNCATED AT 250 WORDS)

Dilatation, Pathologic↗
PubMed1982

[Pulsed Doppler echocardiography in a case of coronary artery-pulmonary artery fistula: analysis of flow pattern within the main pulmonary artery and detection of a small shunt].

Flow pattern within the main pulmonary artery was analysed by pulsed Doppler echocardiography in a case of coronary artery-pulmonary artery fistula. An asymptomatic 32-year-old female was referred to our hospital for evaluation of a continuous murmur in the second interspace at the left sternal border. Other physical findings, chest roentgenograms and electrocardiograms were normal. Two-dimensional echocardiography did not play an important role in the diagnosis. However, pulsed Doppler echocardiography revealed an antegrade turbulent flow along the antero-lateral wall of the main pulmonary artery from early diastole to early systole. The direction and distribution of this abnormal flow was judged to be different from that of patent ductus arteriosus. Coronary arteriography showed a fistula from the both coronary arteries to the proximal portion of the main pulmonary artery. However, its shunt was so small that it could not be detected by oxymetry or by hydrogen-platinum electrode method. This case suggests that Doppler method is very sensitive in shunt detection and possibly useful for non-invasive diagnosis of coronary artery-pulmonary artery fistula.

Adult↗
PubMed1980

Change of the reactivity of sulfhydryl groups of the membrane proteins in response to amino acids in Chang liver cells.

Intensity of fluorescence induced by reaction of a SH-directed fluorogenic reagent with whole Chang liver cells or their plasma membrane preparations which were previously treated with 0.5 mM N-ethylmaleimide (NEM) plus 5 mM leucine was enhanced by 30% or more in the presence of 5 mM leucine or valine in assay medium consisting of Tris-Hepes buffer, pH 6.85, compared with the control. The dissociation constant for binding of leucine to the membrane protein(s) was estimated to be approximately 3 mM from the increments of fluorescence intensity with increasing leucine concentration. On the other hand, the amount of [14C]NEM bound to the membrane preparations pretreated with NEM plus leucine was significantly reduced in the presence of leucine in the reaction medium. A decrease of reactivity of SH groups near the binding sites of the membrane proteins and of mobility of the fluorescent adducts on binding leucine was suggested to explain all these results consistently.

Amino Acids↗