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Biomedical subjects

J Kobayashi

Publications and source records attributed to J Kobayashi.

At least 487 records · Page 27Linked to original sources
PubMed1985

Ninety consecutive corrective operations for tetralogy of Fallot with or without minimal right ventriculotomy.

Eighty-eight patients with tetralogy of Fallot and two patients with ventricular septal defect and pulmonary atresia underwent repair without right ventriculotomy (n = 43) or with a minimal right ventriculotomy (n = 47) of 10 to 15 mm. The ventricular septal defect was closed through the tricuspid valve in 75 patients. The pulmonary valve was either preserved or reconstructed to maintain its competence. The age at operation was 1 or 2 years in 51 patients. There was one operative death and there were no late deaths. The results of postoperative cardiac catheterization in the present series of patients (n = 34) were compared with those of control patients (n = 21) who had repairs with a conventional right ventriculotomy in the preceding period. There was no significant difference in right ventricular/left ventricular systolic pressure ratio or in cardiac index either at rest or during isoproterenol infusion between the two groups. The incidence of significant pulmonary regurgitation (Grade greater than or equal to 2/4) was less (p less than 0.05) in the present patients (47%, n = 34) than in the control patients (81%, n = 21). The right ventricular end-diastolic volume index (ml/m2) was smaller in the present patients than in the control patients both at rest (91 +/- 37 versus 142 +/- 28, p less than 0.01) and during isoproterenol infusion (81 +/- 21 versus 109 +/- 30, p less than 0.01). The right ventricular ejection fraction was higher in the present patients than in the control patients during isoproterenol infusion (57% +/- 4% versus 49% +/- 6%, p less than 0.01). The incidence of ventricular arrhythmias (Lown's grade greater than or equal to 2) was less in the present patients (6/35) than in the control patients (36/65) (p less than 0.005). This method of repair for tetralogy of Fallot carries no more risk than the conventional method, and the results are better with respect to postoperative right ventricular function and ventricular arrhythmia.

Adolescent↗
PubMed1984

Ambulatory electrocardiographic study of the frequency and cause of ventricular arrhythmia after correction of tetralogy of Fallot.

Ambulatory 24-hour electrocardiographic monitoring with a Holter recording system was performed in 100 patients after repair of tetralogy of Fallot. The incidence and severity of ventricular arrhythmia (VA) were studied relative to operative age, follow-up period after corrective surgery, hemodynamic data, ventricular function and operative method. Significant VA (Lown grade 2 to 4) was detected in 41 patients. Patients with significant VA (group I) were older (11.7 +/- 10.0 years old) at operation than those without VA (group II) (5.5 +/- 5.8 years, p less than 0.001). The follow-up period after operation in group I (9.5 +/- 4.8 years) was significantly (p less than 0.001) longer than that in group II (5.5 +/- 4.3 years). The incidence of elevated right ventricular (RV) systolic pressure was significantly (p less than 0.005) higher in group I (43%) than in group II (7%). RV ejection fraction in group I (48 +/- 6%) was significantly (p less than 0.001) lower than that in group II (56 +/- 5%). The new operative method for tetralogy of Fallot without or with minimal right ventriculotomy was more frequently performed in group II (49%) than in group I (15%, p less than 0.005). Pulmonary regurgitation, RV and left ventricular size, and left ventricular ejection fraction were not related to severity of VA. Thus, serious VA was related to higher age at operation, longer interval after surgery, elevated RV systolic pressure, depressed RV ejection fraction and RV scar.

Adolescent↗
PubMed1984

Nuclear magnetic resonance analyses of side chain conformations of histidine and aromatic amino acid derivatives. Solvent and pH dependence.

Stereoselectively beta-deuterated species were synthesized of Ac-His-NHMe, Ac-His-OEt, Ac-His-OH and H-His-NHMe, which are useful as models of histidine residues in peptides. From the spectral comparison of 1H n.m.r., the beta-proton resonances of the normal species were unambiguously assigned. In (C2H3)2SO, C2(2)H5O2H, C2H3O2H, and C5(2)H5N solution and in aqueous solution, the lower-field and higher-field components of beta-proton resonances of the four histidine derivatives are assigned to the pro-R and pro-S protons, respectively. The alternative assignments apply for Ac-His-NHMe, Ac-His-OEt and Ac-His-OH in non-polar solvents such as C2HCl3. Vicinal coupling constants 3J alpha beta S and 3J alpha beta R were obtained for calculating the fractional populations of rotamers about the C alpha-C beta bond. The rotamer populations depend little on the ionization states of the alpha-amino and carboxyl groups or the imidazole ring. The rotamer populations depend significantly on the solvent polarity, similar to those of Phe, Tyr and Trp derivatives. For the two beta-proton resonances of His, Phe, Tyr, and Trp derivatives in a variety of solvents, linear relationships are found between the differences in chemical shifts and the differences in vicinal coupling constants.

Histidine↗
PubMed1984

Alpha-adrenoceptor blocking action of aaptamine, a novel marine natural product, in vascular smooth muscle.

In the rabbit isolated aorta and renal artery, aaptamine (3 X 10(-5)M), a novel heteroaromatic substance isolated from a sea sponge Aaptos aaptos produced a parallel, rightward shift of the dose-response curve for noradrenaline, whereas that for histamine or KCl was not affected. But, the derivatives of aaptamine, demethylaaptamine, demethyloxyaaptamine, dihydroaaptamine and dihydrodemethylaaptamine at concentrations of 10(-5) to 10(-4)M had no effect on the dose-response curve for noradrenaline. These results suggest that aaptamine is a competitive antagonist of alpha-adrenoceptors in vascular smooth muscles.

Adrenergic alpha-Antagonists↗
PubMed1984

[Noninvasive and quantitative evaluations of the severity of isolated pulmonary valvular stenosis using two-dimensional pulsed Doppler echocardiography].

The severity of isolated pulmonary valvular stenosis (PS) was evaluated noninvasively and quantitatively using two-dimensional pulsed Doppler echocardiography (2D-PDE). The subjects consisted of 17 patients with PS diagnosed by cardiac catheterization (3 to 15-year-old with a mean age of 7.9 years) and 28 healthy children (3 to 12-year-old with a mean age of 7.2 years). Flow signals by 2D-PDE were recorded in the right ventricular outflow tract just below the pulmonary valve and in the main pulmonary artery. The following three parameters were measured from the flow signals in the right ventricular outflow tract: the right ventricular pre-ejection period (RPEP) from the onset of the QRS in the electrocardiogram to the beginning of RV ejection in 2D-PDE, the acceleration time from the onset of RV ejection to peak velocity (AcT), and the right ventricular ejection time (RET) from the onset to the end of right ventricular (RV) ejection. Acceleration time index (AcT/RET), and systolic time intervals including RPEP/RET, RPEP/square root RR and RET/square root RR in PS were compared with those of the controls. The correlations between the above-mentioned parameters and pressure gradients and RV systolic pressures in PS were examined. Data were expressed as mean value +/- SD. AcT/RET ranged from 0.37 to 0.53 (0.45 +/- 0.04) in the controls and from 0.54 to 0.76 (0.62 +/- 0.07) in PS. The mean AcT/RET was significantly greater in PS than in the controls (p less than 0.001). There was a highly positive correlation of AcT/RET with pressure gradients (r = 0.94) and RV systolic pressures (r = 0.93). RPEP/RET ranged from 0.32 to 0.47 (0.37 +/- 0.04) in the controls and from 0.24 to 0.35 (0.29 +/- 0.03) in PS, and the mean was significantly lower in PS than in the controls (p less than 0.001), and this was caused by the short RPEP and prolonged RET. RPEP/square root RR ranged from 102 to 160 msec (122 +/- 16 msec) in the controls and from 86 to 136 msec (107 +/- 16 msec) in PS, and the mean was significantly shorter in PS (p less than 0.05). RET/square root RR ranged from 300 to 345 msec (323 +/- 13 msec) in the controls and from 308 to 417 msec (363 +/- 27 msec) in PS, and the mean was significantly longer in PS (p less than 0.001). The pressure gradient and RV systolic pressure in PS did not correlate with RPEP/RET, RPEP/square root RR and RET/ square root RR.4+ 102 to 160 msec (122 +/- 16 msec) in the controls and from 86 to 136 msec (107 +/- 16 msec) in PS, and the mean was significantly shorter in PS (p less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗