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Biomedical subjects

H Oku

Publications and source records attributed to H Oku.

At least 163 records · Page 9Linked 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

Factors affecting biventricular function following surgical repair of tetralogy of Fallot.

Right and left ventricular functions were assessed in children following surgical repair of tetralogy of Fallot. The results were analyzed with regard to the relative contribution of preoperative, perioperative and postoperative factors to postoperative functional abnormalities. Pulmonary regurgination of our Grade 3 or more depressed right and left ventricular ejection fractions and enlarged right ventricular end-diastolic volume. Right and left ventricular ejection fractions in patients with residual right ventricular outflow pressure gradients over 30 mmHg were significantly lower than those in patients with pressure gradients of 30 mmHg or less. The majority of those pressure gradients were at the pulmonary annulus or central pulmonary artery. Right and left ventricular ejection fractions were significantly lower in patients with a preoperative aortic oxygen saturation of less than 80% than in patients with one of 80% or more. The 3 variables of pulmonary regurgitation, residual pulmonary stenosis, preoperative aortic oxygen saturation were statistically independent. Left ventricular ejection fraction and end-diastolic volume correlated with the right ventricular ejection fraction and end-diastolic volume, respectively (r = 0.63, r = 0.68). These results show that severe pulmonary regurgitation, significant annular or central pulmonary stenosis and preoperative hypoxia are major contributing factors to right ventricular dysfunction after surgical repair of tetralogy of Fallot. The postoperative left ventricular dysfunction can be largely attributed to dysfunction of the right ventricle.

Cardiac Catheterization↗
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↗
PubMed1988

[Detection of left ventricular thrombi after acute myocardial infarction using Ga-67-DFO-DAS-fibrinogen].

Ga-67-DFO-DAS-fibrinogen (Ga-fbg) scintigraphy, a new radiopharmaceutical method, was performed for detecting intraventricular thrombi following acute myocardial infarction in five patients. The thrombi in four of them were detected by two-dimensional echocardiography (2DE) and that in the fifth patient was suspected during magnetic resonance imaging. Imaging of the heart was performed using a scinticamera with a medium energy collimator and multiple views (anterior, LAO 30 degrees, LAO 45 degrees, and lateral) three and four days after the intravenous administration of Ga-fbg. By Ga-fbg scintigraphy, intraventricular thrombi were detected in four patients. The size of the thrombi visualized by Ga-fbg appeared larger than those by 2DE. In one patient examined again after anticoagulant therapy, a thrombus was missed by 2-DE, but it was detected by Ga-fbg, though the radioactivity of the thrombus decreased. We concluded that Ga-fbg scintigraphy is a very simple method and sufficiently useful for detecting active left ventricular thrombi and for monitoring the effect of anticoagulant therapy. It could be more sensitive than 2DE for determining the extent of an active intraventricular thrombus.

Adult↗
PubMed1987

Alterations in myocardial systolic and diastolic function in patients with active systemic lupus erythematosus.

Echocardiographic studies were performed to evaluate myocardial function in active patients with systemic lupus erythematosus (SLE). Fourteen patients were studied in the active stage before corticosteroid therapy (active SLE); 10 of them were reexamined after therapy (inactive SLE). Computer-assisted analysis of digitized echoes of the left ventricular dimension was performed. The peak rate of change in dimension during systole (-dD/dt) was reduced in active SLE compared with normal control subjects (2.57 +/- 0.15 cm/sec vs 3.37 +/- 0.14 cm/sec, p less than 0.01). The peak rate of change in dimension during diastole (+dD/dt) was also reduced in active SLE compared with normal control subjects (3.16 +/- 0.19 cm/sec vs 4.41 +/- 0.20 cm/sec, p less than 0.01). After therapy, -dD/dt in inactive SLE was improved compared with active SLE (from 2.56 +/- 0.20 cm/sec to 3.13 +/- 0.19 cm/sec, p less than 0.001). Positive dD/dt in inactive SLE was also improved compared with active SLE (from 3.29 +/- 0.22 cm/sec to 4.23 +/- 0.23 cm/sec, p less than 0.01). No significant differences were found between inactive SLE and normal control subjects as to -dD/dt and +dD/dt. Significant correlations were found between anti-DNA antibody titers and both -dD/dt and +dD/dt (r = -0.97 p less than 0.0001, and r = -0.71 p less than 0.05, respectively). These results suggest that active SLE patients have left ventricular dysfunction that may be caused by an immunopathologic mechanism in SLE.

Adolescent↗
PubMed1987

Identification method for twelve oligomannose-type sugar chains thought to be processing intermediates of glycoproteins.

A mixture of the pyridylamino (PA) derivatives of 12 oligomannose-type sugar chains was fractionated into five fractions (mannose5N-acetylglucosamine2-PA approximately mannose9N-acetylglucosamine2-PA) by size-fractionation HPLC with a MicroPak AX-5 column. Each fraction thus obtained was then analyzed by reversed-phase HPLC with a Cosmosil 5C18-P column. In this way, the 12 PA-oligomannose-type sugar chains were completely separated from each other. The method was used to identify the structures of oligomannose-type sugar chains of human C3, the third component of human complement.

Carbohydrate Sequence↗
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

Postoperative long-term results in total correction of tetralogy of Fallot: hemodynamics and cardiac function.

Late results were assessed in 63 patients who underwent complete repair of tetralogy of Fallot. These patients were divided into four groups. Group I-A included 13 who had a transannular patch with a monocusp, and whose cross-sectional area index (CSAI) was less than 2.5 cm2/m2; group I-B included 11 with the patch and with a CSAI greater than 2.5 cm2/m2. Group II included 27 patients who underwent pulmonary valvotomy. Group III included 9 who had not undergone valvotomy and 3 who had undergone pulmonary valve replacement. Late death occurred in 1 patient, and reoperation was done on 3. Mild pulmonary stenosis (PS) was present in 73%, moderate PS in 17%, and severe PS in 10% of the patients. A significant pulmonary regurgitation (PR) of grade 3 or 4 was present in 33% of the patients in group I-A, and in 87% of group I-B, 17% of group II, and 0% of group III. Right ventricular end-diastolic volume was normal in patients with a PR of grade 2 or less, and it was higher in patients who had a significant PR. The ejection fraction was generally decreased, regardless of the grade of PR. Left ventricular function was normal in those with a PR of grade 3 or less and was impaired in those with a PR of grade 4. Thus, late postoperative hemodynamics and ventricular function were excellent in patients with a mild PS and a PR of grade 2 or less and it was poor in those with a moderate PS and a significant PR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Decreased water and potassium content in erythrocytes in essential hypertension.

The water content in erythrocytes of subjects with borderline or established essential hypertension was measured by using gas-liquid chromatography and was found to be lower than that in normotensive controls (p less than 0.01). The water content in erythrocytes of normal controls (n = 14), borderline hypertensive subjects (n = 18), and established essential hypertensive subjects (n = 23) was (mean +/- SE) 71.0 +/- 0.2%, 69.9 +/- 0.2%, and 69.3 +/- 0.1% (vol/vol), respectively. A definite negative correlation was found between water content of erythrocytes and mean arterial pressure in normotensive and hypertensive subjects (n = 60, r = -0.59, p less than 0.001). Although there was no statistically significant between-group difference in the sodium content, the potassium content of erythrocytes from subjects with essential hypertension was significantly lower than that of normotensive controls (0.205 +/- 0.003 vs 0.222 +/- 0.004 mumol/mg dry red blood cells; p less than 0.01). There was no between-group correlation of sodium and water content in erythrocytes, but the potassium content correlated with the water content (n = 46, r = 0.49, p less than 0.001).

Blood Pressure↗
PubMed1986

Postoperative long-term results in total correction of tetralogy of Fallot: with special reference to method and degree of relief of right ventricular outflow tract obstruction.

Late results were studied in 63 patients who underwent complete repair of tetralogy of Fallot. Mild pulmonary stenosis (PS) was present in 73%, moderate PS in 17% and severe PS in 10% of the patients. When a transannular patch was used, wider enlargement of the pulmonary annulus did not always relate to a decrease in right ventricular pressure and right ventricular to pulmonary artery pressure gradient in the late postoperative period. Pulmonary regurgitation (PR) of grade 2 or less did not relate to the late postoperative hemodynamics and cardiac function. PR of grade 3 or over led to right ventricular and pulmonary artery hypertension, and to increases in right ventricular end-diastolic volume and CTR. PR of grade 4 impaired left ventricular function. PR of grade 3 or over with moderate PS led to elevation in right ventricular end-diastolic pressure. In patients with mild PS and PR of grade 2 or less, late postoperative hemodynamics and cardiac function were excellent. To maintain excellent postoperative hemodynamics and cardiac function, it is imperative to obtain PR of grade 2 or less and to use a procedure which will lead to excellent development of the pulmonary annulus. In conventional procedures using a transannular patch, a CSAI of less than 2.5 cm2/m2 and precise coaptation between the original pulmonary cusp and the cusp mounted on the patch will aid in avoiding significant PR.

Adolescent↗