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Biomedical subjects

T Nishikimi

Publications and source records attributed to T Nishikimi.

101 records · Page 6Linked to original sources
PubMed1988

Physiological significance of atrial natriuretic peptides in essential hypertension.

To investigate the significance of atrial natriuretic peptides (ANP) in essential hypertension, plasma ANP concentrations in 43 essential hypertensives, 16 borderline hypertensives and 17 normotensive controls were measured. Furthermore, effects of high-sodium and low-sodium intakes on plasma ANP concentration were examined in "salt-sensitive" [SS] and "nonsalt-sensitive" [NSS] patients with essential hypertension. Plasma ANP concentration was significantly higher in hypertensives than in borderline hypertensives and in normotensive controls. No significant difference in plasma ANP concentration was observed between borderline hypertensives and normotensive controls. Plasma ANP concentration increased with the high-sodium diet in both the SS and NSS patients, but the mean increment was significantly greater in the SS than the NSS patients. Urinary excretion of sodium was lower in the SS patients taking the high-sodium diet than the corresponding value in the NSS patients. These findings suggest that an increased level of circulating ANP in hypertensive patients represents a compensatory mechanism to offset further elevation of blood pressure and sodium retention.

Atrial Natriuretic Factor↗
PubMed1988

[Regional left ventricular diastolic dysfunction in patients with apical hypertrophy].

Differences in cardiac function between the apical and the chordal parts of the left ventricle in apical hypertrophy (APH) were investigated by M-mode echocardiography. The subjects consisted of 10 patients with APH (APH Group) and 10 normal controls (N Group). The M-mode echocardiograms of the interventricular septum (IVS) and left ventricular posterior wall (LVPW), both in the apical and chordal parts were simultaneously recorded with the electrocardiogram and phonocardiogram. There were no significant differences in the blood pressures, heart rates, left ventricular end-diastolic internal diameters, and left ventricular end-systolic internal diameters between the APH Group and the N Group. The hypertrophy was localized to the IVS and LVPW of the apical part in the APH Group. In the chordal part, there were no significant differences in the peak negative dD/dt (-dD/dt) and the time to the peak filling rate (TPFR) between the APH Group and N Group. In the apical part, -dD/dt of the APH Group tended to increase compared with that of the N Group. The TPFR of the APH Group was significantly longer than that of the N Group (APH Group: 167 +- 33 msec and N Group: 126 +- 19 msec, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Cardiac function of patients with essential hypertension during exercise and isoproterenol infusion.

The left ventricular function of patients with essential hypertension was examined during exercise and isoproterenol (ISP) infusion echocardiography. Twenty-eight hypertensive patients without cardiac hypertrophy (Group NH), 20 patients with cardiac hypertrophy (Group HH), 7 patients with cardiac dilatation (Group D), and 13 normotensives (Group N), were studied during multistage exercise using a supine bicycle ergometer. In addition, 23 hypertensives (Group NH: 13 patients, Group HH: 10 patients) and 10 normotensives were studied during ISP infusion (0.005 microgram/kg/min, and 0.01 microgram/kg/min, respectively, for 5 min). To assess the left ventricular function, an M-mode echocardiogram was utilized at rest and during exercise and ISP infusion. At rest, the isovolumic relaxation time (IRT) of each hypertensive group was significantly longer than that of Group N. IRT of Group HH and Group D was significantly longer than that of Group NH. Only the shortening fraction (SF) of Group D was significantly smaller than that of Group N. During exercise the SF increased in all groups, and only the SF of Group D was significantly smaller than that of Group N at a load of 75 W as well as at rest. The SF of Group HH tended to be smaller. There was no significant difference in peak negative dD/dt (-dD/dt) between any of the groups at rest; however, the -dD/dt of Group HH was significantly smaller than that of Group N during ISP infusion. We concluded that left ventricular diastolic function was disturbed in each hypertensive group at rest. Diastolic dysfunction worsened in Group HH and Group D. Only the left ventricular systolic function of Group D was already depressed at rest. Furthermore, unmanifested systolic dysfunction of the left ventricle seemed to be present in Group HH, because SF during exercise tended to be smaller and -dD/dt during ISP infusion was significantly smaller than that of Group N.

Adult↗
PubMed1986

Circulating atrial natriuretic polypeptide during exercise in patients with essential hypertension.

We studied the relationship between haemodynamic measurements and plasma atrial natriuretic peptide (ANP) levels during exercise in patients with essential hypertension. The exercise protocol consisted of three fixed work loads (25, 50 and 75 W) using a supine bicycle ergometer. Plasma ANP levels and haemodynamic indices were measured before and during each stage of exercise. Plasma ANP levels and pulmonary artery wedge pressure (PAWP) significantly increased at the maximum work load. Significant correlations of PAWP and mean arterial pressure (MAP) to plasma ANP levels were observed at four points obtained before and during each stage of exercise (PAWP, r = 0.83, P less than 0.001; MAP, r = 0.48, P less than 0.01). Furthermore, a significant inverse correlation between shortening fraction (SF), estimated by M-mode echocardiography, and plasma ANP levels at 75 W work load was also observed (r = -0.66, P less than 0.01). These results suggest that the increase of circulating ANP levels during exercise in essential hypertensive subjects may be associated with elevated left atrial pressure and arterial pressure, or left ventricular systolic dysfunction.

Adult↗
PubMed1986

[Left ventricular wall motion abnormalities evaluated by factor analysis as compared with Fourier analysis].

Factor analysis was applied to multigated cardiac pool scintigraphy to evaluate its ability to detect left ventricular wall motion abnormalities in 35 patients with old myocardial infarction (MI), and in 12 control cases with normal left ventriculography. All cases were also evaluated by conventional Fourier analysis. In most cases with normal left ventriculography, the ventricular and atrial factors were extracted by factor analysis. In cases with MI, the third factor was obtained in the left ventricle corresponding to wall motion abnormality. Each case was scored according to the coincidence of findings of ventriculography and those of factor analysis or Fourier analysis. Scores were recorded for three items; the existence, location, and degree of asynergy. In cases of MI, the detection rate of asynergy was 94% by factor analysis, 83% by Fourier analysis, and the agreement in respect to location was 71% and 66%, respectively. Factor analysis had higher scores than Fourier analysis, but this was not significant. The interobserver error of factor analysis was less than that of Fourier analysis. Factor analysis can display locations and dynamic motion curves of asynergy, and it is regarded as a useful method for detecting and evaluating left ventricular wall motion abnormalities.

Adult↗
PubMed1985

Pseudo-coarctation of the abdominal aorta associated with renovascular hypertension.

A case of pseudo-coarctation of the abdominal aorta associated with renovascular hypertension has been reported. The abdominal aorta of the patient was kinked at the level of L1-L2 without a pressure gradient, which was consistent with pseudo-coarctation of aorta. Both renal arteries arose from the aorta at the level of lower T12 and had severe multiple stenoses. We have discussed the possible etiology of the developmental abnormalities of the arterial system in this patient.

Adult↗
PubMed1985

[Left ventricular function in essential hypertension during isoproterenol infusion].

The left ventricular function of 23 patients with essential hypertension was investigated during infusion of isoproterenol (ISP). These patients consisted of 13 without cardiac hypertrophy (Group NH) and 10 with cardiac hypertrophy (Group HH). Ten normotensive subjects served as normal controls. To assess left ventricular functions, M-mode echocardiograms were recorded at rest and after ISP infusion for 5 minutes (0.005 and 0.01 microgram/kg/min). There were no significant differences in peak negative dD/dt in all groups at rest. But peak negative dD/dt of Group HH significantly decreased after an infusion of 0.005 microgram/kg/min ISP (Group N: 3.43 +/- 0.69, Group NH: 3.15 +/- 0.61, and Group HH: 2.49 +/- 0.48 cm/sec, respectively). The peak negative dD/dt of Group HH was also significantly decreased after a dose of 0.01 microgram/kg/min. Among all patients with hypertension, peak negative dD/dt correlated inversely with left ventricular mass (LVM) after the infusion of ISP (0.005 microgram/kg/min: r = -0.64, p less than 0.001, 0.01 microgram/kg/min: r = -0.68, p less than 0.001). The peak positive dD/dt of Group HH was significantly decreased only when compared with that of Group N at rest (Group N: 3.15 +/- 0.75, Group NH: 3.02 +/- 0.86, and Group HH: 1.92 +/- 0.68 cm/sec, respectively). The difference between the peak positive dD/dt of Group HH and that of Group N was more prominent after the infusion of ISP than at rest. Among all patients with hypertension, the peak positive dD/dt was inversely related to LVM at rest (r = -0.64, p less than 0.002). There was a similar relation between the two indexes after the infusion of ISP. Peak positive dD/dt was related to peak negative dD/dt after a dose of 0.01 microgram/kg/min in Group HH (r = 0.67, p less than 0.05). There was no significant difference in heart rate, change in blood pressure, or total peripheral vascular resistance after the infusion of ISP. It is concluded that diastolic left ventricular dysfunction and latent systolic left ventricular dysfunction are related to increased LVM in Group HH. It seems that after the infusion of ISP severe diastolic left ventricular dysfunction is related to latent systolic left ventricular dysfunction.

Adult↗