Biomedical subjects
Publications and source records attributed to S Kitamura.
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To establish the measurement method of right ventricular (RV) volume by two-dimensional (2-D) echocardiography, a comparative study was performed in respect to the quantitative evaluations of the RV areas or volumes obtained by biplane 2-D echographic and angiographic methods. At first, a preliminary investigation was performed to define the optimum tracing of the endocardial surface on the 2-D echogram by using a fresh mongrel dog heart. It was revealed that the 2-D echographic views of the ventricular surface contained some artifact echoes inside the true echo of the endocardium. As a result, the optimum line for tracing was considered to be in external margin of the echo which seemed to represent the endocardium. This technique was then applied to 10 patients with congenital heart disease who were followed by cardiac catheterization. Ages ranged from 9 months to 5 years with an average of 2 years and 4 months. The RV was imaged by a subxiphoid approach. The RV apex, pulmonary valve (PV) and mid-portion of the tricuspid valve were showed in a frontal view, which allowed to measure the frontal RV area (f). In a sagittal plane, the RV wall and the PV were imaged, and then the lateral area (l) and the RV long axis (d) were measured. From the biplane cineangiography, the frontal RV area (f') lateral area (l'), RV long axis (d') and RV end-diastolic volume (EDV) by arealength method were calculated. The f and l were correlated with the f' (r = 0.90) and with the l' (r = 0.86), respectively. However, the values by the echocardiographic measurement were smaller than those by the cineangiographic ones. The f was also well correlated with the RVEDV (r = 0.94). The f.l/d, considered to represent a variable of echography measurement of the RV volume by area-length method, was well correlated with the RVEDV (r = 0.84). Although there are still some problems related to the imaging technique and sharpness of the echogram, further improvement to establish a echocardiographic measurement of RV volume is expected with the advance of the techniques.
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Vasoactive intestinal polypeptide (VIP) increased the cyclic AMP content of guinea pig lung and tracheal tissues. Combinations of the peptide with prednisolone or with phenoxybenzamine potentiated the effect of VIP on cyclic AMP. The trachea-relaxant effect of VIP also was reinforced by the addition of prednisolone or phenoxybenzamine. At the same time, cyclic GMP content in these tissues changed little in response to these agents. The results provide a biochemical basis for the tracheal-relaxant action of these agents, and for the potentiation of bronchodilation by prednisolone and by alpha-receptor blockade. The findings are also consistent with the view that relaxation of airway smooth muscle is mediated by an elevation of intracellular cyclic AMP.
With use of biplane cineangiocardiograms, ventricular cavity volume measurements were determined in 17 patients with single ventricle, before total correction. There were 4 patients with a single left and 13 with a single right ventricle. Atrioventricular (A-V) valve regurgitation was evident in 6 of 13 patients with a common A-V valve. End-diastolic volume index ranged from 72 to 282 ml/m2 (average 131 ml/m2), and these values ranged from 71 to 206 percent (average 110 percent) of the sum of the normal left and right ventricular end-diastolic volumes. Ejection fraction averaged 0.55. There was no significant difference in ventricular cavity volume characteristics and ventricular function between patients with single and and single right ventricle. The single ventricle ejects blood to both the systemic and the pulmonary circulatory beds. There was a high correlation of end-diastolic volume index with pulmonary to system flow ratio (r = +0.89, p less than 0.001). This observation indicates that the major factor affecting ventricular cavity volume in single ventricle is pulmonary blood flow and a systemic to pulmonary arterial shunt should increase the ventricular cavity volume. Ventricular function of single ventricle was depressed. The ejection fraction of patients with A-V valve regurgitation averaged 0.49, which was significantly lower than that (0.58) of patients without regurgitation (p less than 0.05). A-V valve regurgitation was also a factor that increased ventricular cavity volume, although the ventricular function became more depressed.
Five patients with tetralogy of Fallot associated with aortic insufficiency were studied. They ranged from 6 to 34 years old (mean, 14 years), and 2 patients had a history of subacute bacterial endocarditis. Four patients had a bulboventricular type of ventricular septal defect. Prolapse of the right coronary cusp was the main cause of aortic insufficiency. Deformed valve secondary to subacute bacterial endocarditis and severe dilatation of the aortic annulus were the other causes. In addition to repair of the tetralogy defect, aortic valvuloplasty was performed in 2 patients. In the remaining 3 patients, the ventricular septal defect was closed with a relatively small-sized patch and no aortotomy was made. Four patients survived the operation, and no residual aortic insufficiency was observed in 3 of them. The etiology and the method of operation are discussed.
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The sulfoxide reduction of sulindac (cis-5-fluoro-2-methyl-1-[p-(methylsulfinyl)-benzylidenyl]indene-3-acetic acid), an anti-inflammatory agent, was demonstrated in vitro by cell-free preparations of guinea pig liver. The sulfoxide reductase activity was located in both fractions of microsomes and 105000X g supernatant. The microsomal reductase was NADPH- or NADH-dependent, and required the factor present in the soluble fraction for its activity. The factor was heat-labile and non-dialyzable. Furthermore, a partial purification of the microsomal NADPH-cytochrome c reductase resulted in a paralleled increase of the sulfoxide reductase activity. The present observations suggest that the soluble factor described above functions as an electron transfer component coupled with NADPH-cytochrome c reductase.
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The uptake of amino acids and glucose by microfilariae of Dirofilaria immitis maintained for 8 days in vitro was studied. The quantity of glutamic acid, histidine, lysine, alanine, tryptophan, and cystine in the medium did not change. Isoleucine, serine, valine, phenylalanine, tyrosine, methionine, and cystathionine decreased slightly; both asparatic acid and leucine decreased considerably. Glutamine, threonine, and proline decreased markedly, while glycine increased to some extent. Ornithine increased and arginine decreased; however, their changes were smaller than the changes of respective amino acids in the control medium free of microfilariae. Glucose decreased markedly.
The effect of 2-[N-(n-butyloyl)homopiperazin-N'-yl]-4-amino-6,7-dimethoxy quinazoline hydrochloride (E-643), a new alpha-adrenergic receptor blocking agent, on the relaxing responses and on the change of cyclic AMP and cyclic GMP contents in guinea pig tracheal (GPT) tissues induced by various bronchodilators was examined. The relaxing responses and the cyclic AMP and cyclic GMP contents in GPT induced by isoprenaline, adrenaline, prostaglandin E2 and chlorprenaline were markedly enhanced with continuous infusion of E-643. These results may suggest that E-643 can be used together with various bronchodilators for the treatment of chronic obstructive pulmonary diseases.
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