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Biomedical subjects

S Hirata

Publications and source records attributed to S Hirata.

At least 181 records · Page 10Linked to original sources
PubMed1988

Two-dimensional echocardiography in acute myocardial infarction--relationship between left ventricular wall thickness and wall motion abnormalities.

An attempt was made to examine left ventricular wall thickness and wall motion using two-dimensional echocardiography from the acute phase to 1 month after onset of myocardial infarction. Motion abnormalities and thinning of the wall were observed from immediately after the onset. Few areas that were akinetic or dyskinetic and had a wall thickness of 7 mm or less during the acute phase showed improvements in wall motion 1 month later. However, some areas with a wall thickness of 8 mm or more did reveal improved wall motion even if they were akinetic or dyskinetic during the acute phase. Since the akinetic or dyskinetic areas with a wall thickness of 7 mm or less during the acute phase demonstrated a positive correlation with the peak CPK and nQ, and a negative correlation with the left ventricular ejection fraction 1 month after the onset, they were considered to be necrotic zones of myocardial infarction. The area of abnormal wall motion, on the other hand, was considered to correspond to a wider area including the ischemic as well as the necrotic zones. Evaluation of the necrotic and ischemic areas of infarction separately from the acute phase appears to be useful not only for the selection of treatment during the acute phase but also for predicting the cardiac function 1 month later and for determining the time of initiation and method of cardiac rehabilitation.

Adult↗
PubMed1988

[Enzyme immunological measurement of estrogen receptors in the human endometrium by the use of monoclonal antibody].

The concentrations of cytosol (ERc), nuclear (ERn), and total (ERc+n) estrogen receptors were determined by Enzyme Immunoassay using Monoclonal Antibody, in normal endometrium freshly obtained from 13 cases, and were compared with those determined by a conventional ligand binding assay on LH-20 (LH-20 assay). There was good correlation between EIA and LH-20 values. The correlation coefficients for ERc, ERn and ERc+n were 0.960, 0.980 and 0.950, respectively. Regression lines were as follows; Ec = 1.22Lc-4.07, En = 1.18Ln+37.7 and Ec+n = 1.27 Lc+n-158.4. These results clearly demonstrate the applicability of the ER-EIA for the determination of estrogen receptors in the endometrium. Particularly for clinical laboratory purposes, the enzyme immunoassay has some advantages over the conventional binding assay in terms of non-radioactivity and simple procedure.

Adult↗
PubMed1987

Modulation of brain progestin and glucocorticoid receptors by unsaturated fatty acid and phospholipid.

In an attempt to learn how nonsteroidal factors modulate brain progestin and glucocorticoid receptors, the effects of saturated and unsaturated fatty acids, and phosphatidylinositol on the binding of [3H]R5020 or [3H]dexamethasone, determined by sucrose density gradient and gel filtration on LH20, were examined in the cerebral cortical cytosol from 10-day-old female rats which contain a considerable amount of progestin and glucocorticoid receptors. Unsaturated fatty acids such as oleic (C18:1), arachidonic (C20:4) and docosahexaenoic acid (C22:4) depressed the [3H]R5020 or [3H]dexamethasone binding in increasing order, but saturated fatty acids had no effect. Arachidonic and docosahexaenoic acids, which were strong inhibitors, lowered the binding dose dependently. The fatty acid inhibition on brain progestin and glucocorticoid receptors was thus a function of acid dose and degree of acid unsaturation. Interestingly, prostaglandin D2 did not show any effect. Among phospholipids tested the inhibitory effect of phosphatidylinositol on the [3H]R5020 binding was evident, but no significant effect was found with phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine or sphingomyelin. The phosphatidylinositol inhibition was dose dependent. Analysis on kinetics and Scatchard plot have revealed the noncompetitive type of inhibition by arachidonic acid and phosphatidylinositol. From these results it is suggested that the unsaturated nonestrified fatty acid, arachidonic acid, and phosphoinositides modulate the brain progestin and, possibly, glucocorticoid receptors through their binding at sites different from steroid binding sites on the respective receptor molecules.

Animals↗
PubMed1987

[V1P-terminal force evaluated by left ventricular inflow velocity patterns in pulsed Doppler echocardiography].

The relationship between V1P-terminal force (V1-PT) and the characteristics of left ventricular (LV) diastolic filling and atrial contraction were evaluated using LV inflow velocity patterns obtained by pulsed Doppler echocardiography. Subjects consisted of 54 patients with old myocardial infarction, 56 with essential hypertension, 48 with angina pectoris, 19 with dilated cardiomyopathy, and 16 with miscellaneous disease other than of mitral valve lesions. The patients were classified as the positive group: V1-PT less than or equal to -0.04 mmsec, intermediate group: 0 greater than V1-PT greater than -0.04 mmsec, and negative group: V1-PT greater than or equal to 0 mmsec. The following were the results obtained: 1. In the positive group, the rapid filling wave (R) had reduced velocity, the prolonged deceleration time and the decreased acceleration and deceleration ratios. 2. In the positive group, velocity of the atrial contraction wave (A) was increased and the atrial contraction time was prolonged compared to the other groups. 3. In the positive group, the A/R was greater than in the other groups. 4. In the positive and intermediate groups, V1-PT correlated significantly with the A/R (r = 0.83, p less than 0.01), R (r = -0.58, p less than 0.01) and A (r = 0.48, p less than 0.01). In the positive group, LV inflow volume was decreased in the rapid filling phase. In the atrial contraction phase, the inflow volume was increased to compensate for loss of inflow volume in the rapid filling phase. These findings suggested that LV diastolic filling was disturbed in the positive group. In conclusion, the value of V1-PT is influenced by any disturbance of LV diastolic filling.

Adult↗
PubMed1985

Characteristics of growth and palatal shelf development in ICR mice after exposure to methylmercury.

A single dose of 25 mg/kg methylmercuric chloride (MeHg) was given orally to gravid ICR mice. Cleft palate was induced in 100% of the offspring, with the critical treatment period ranging from day 10/8 hours (10/8) to 12/16 of gestation. Dose-dependent body weight reduction was observed in day 18 fetuses from both the day 10/8 and 12/16 groups. However, fetal weight reduction was greater in the day 12/16 group for all the MeHg treatments investigated. The relative potency of the induction of cleft palate by MeHg was slightly but significantly higher in the fetuses of the day 12/16 group (1.044-1.197-fold in 95% limits) than in the day 10/8 group. The results showed that when 25 mg/kg of MeHg was given to the fetuses in the day 10/8 group, palatal shelf growth was delayed at a more primitive stage than in the day 12/16 fetuses. Moreover, disharmony of development between the overall fetus and palatal shelf was noticed. Furthermore, in the day 12/16 fetuses, a delay of palatal shelf growth occurred just prior to shelf elevation. Prior to shelf elevation, coordination was probably lost in the development between the fetus and the palatal shelves. Normal palatal closure in ICR fetuses occurs about 1 day and 10 hours earlier (P less than 0.05) than in the A/J fetuses (Biddle, '80). Normal palatal shelves in ICR fetuses moved rapidly, with 3.0 to 5.7 hours (in 95% limits) required for all fetuses to achieve elevation, while, in MeHg-treated groups, palatal shelf elevation did not occur. The results suggest that the cause of the failure in palatal shelf elevation may be understood by examining the disharmonious development of the fetus after exposure to MeHg.

Animals↗
PubMed1985

[Neovascularization around tumors in esophageal carcinoma].

We studied neovascularization around tumors in correlation with other histological findings in 54 resected esophageal carcinomas. The resected materials were divided into positive (more marked) and negative (less marked) vascularization groups according to the degree of neovascularization. So classified, the carcinomas were equally divided. There were significantly more advanced cases of depth of tumor invasion (a-factor) in the positive than in the negative group, and the grade of neovascularization around the tumor tended to increase with the depth of invasion (a-factor). In the a1-3 cases, the rates of nodal metastasis and lymphatic vessel invasion in the positive group were significantly higher than in the negative group. The two-year survival rate of the former appeared to be inferior to the latter. We concluded that neovascularization around a tumor in esophageal carcinoma is an index of tumor malignancy and prognosis.

Adult↗
PubMed1984

[Non-invasive estimates of hemodynamics in normal pregnancy].

Pregnancy provides excellent opportunities for observing the hemodynamic alterations in cardiac function occurring during the physiologic stress imposed on the normal myocardium. Hemodynamically, the most important change in the maternal circulation during pregnancy is an increase in the circulating blood volume and cardiac output. In the average woman, the cardiac output at rest rises 30-50% above the normal non-gestational resting value. Echocardiography was performed for 25 normal pregnant women, ranging in age from 21 to 36 years (mean age of 28.7 years). Echocardiography was performed periodically through out pregnancy, at the gestational ages of the 10th, 24th, 32nd, 36th, and the 3rd postpartal weeks. Tracings were obtained in the left lateral and supine positions. All pregnancies were uncomplicated, and there was no twin pregnancy. The heart rate increased throughout gestation. However, the systolic and diastolic blood pressures did not change significantly throughout pregnancy. End-diastolic left ventricular dimension (LVDd) increased throughout gestation, with the peak at the 36th week of gestation. Left atrial dimension (LAD) and mVCF increased at the 36th week of gestation. Throughout gestation, the ejection fraction (EF) showed no significant change. There were no measurable differences in the cardiac size and function in the left lateral and supine positions. Increased LVDd and LAD throughout gestation were thought the reflexion of the increased blood volume and venous return which had its peak in the 36th week of gestation. The slightly larger cardiac size and end-diastolic volume seemed to induce the increased myocardial fiber stretch and, in turn, the increased mVCF. Our results indicated that chronic volume overload with increased circulating blood volume occurs in normal pregnancy, resulting in the large cardiac size and increased contractility of myocardial fiber.

Adult↗
PubMed1983

Heart rate-independent energetics and systolic pressure-volume area in dog heart.

Left ventricular (LV) systolic pressure-volume area (PVA), a new measure of total mechanical energy for the contraction, linearly correlates with its oxygen consumption per beat (VO2) regardless of contraction mode in a canine heart with stable chronotropism and inotropism. PVA is the area in the pressure-volume (PV) diagram circumscribed by the end-systolic and end-diastolic PV relation curves and the systolic segment of the PV loop and has dimensions of energy. We investigated whether primary changes in heart rate would affect the VO2-PVA relation. In the excised cross-circulated canine heart with left ventricular load controlled with a servo pump, we changed heart rate by pacing to compare the VO2-PVA relations at low [124 +/- 17 (SD) min-1] and high (193 +/- 23) heart rates. In 15 left ventricles, VO2 (ml O2 X beat-1 X 100 g LV-1) was (1.75 +/- 0.57) X 10(-5) PVA (mmHg X ml X beat-1 X 100 g LV-1) + 0.031 +/- 0.011 (ml O2 X beat-1 X 100 g LV-1). The VO2-PVA relation was virtually independent of heart rate in individual hearts. We conclude that the load-independent VO2-PVA relationship is not affected by chronotropism in a given canine left ventricle.

Animals↗