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Biomedical subjects

T Hata

Publications and source records attributed to T Hata.

At least 559 records · Page 31Linked to original sources
PubMed1983

[Ocular and auditory organs of Ochotona rufescens].

Ochotona rufescens is an animal species native to Afghanistan, and is among many new animal species currently being raised for use in experimental research in Japan. In the present paper, we report morphological findings on ocular and auditory character of Ochotona rufescens examined first under normal conditions and then under the influence of various agents, and the results were compared with those on other experimental animals used in this study. On histological examination, the cochlear portion of the labyrinth was found to consist of a coiled canal making two and one half turns from its basal end to the upper turn, and was identical to those of cats and rabbits. Moreover, triple rows of outer sensory hair cells and a single row of inner sensory hair cells were observed. Kanamycin and furosemide (Lasix), a diuretic, were administered 10 min. apart to determine the effects of these drugs on pinna reflex, however, as a result of these administration, none of the Ochotona rufescens tested showed any appreciable depression of this reflex. By funduscopic observation with photographic records, principal retinal arteries were hardly demonstrable except for extremely vague chorioidal vessels, in the layer of the pigmented epithelium which had a puce-like color. Ay contrast, retinal veins were seen in the fundus oculi, as well as whitish optic nerves. The amplitude of the "a" wave in the electroretinogram (ERG) of Ochotona rufescens was only 1/6 that of albino rats or albino rabbits, but the "b" wave was similar in amplitude for all these three species.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

[Calcification of the tricuspid annulus in association with pulmonary stenosis: report of a case].

A 51-year-old woman was admitted to our hospital because of palpitation, dyspnea and anterior chest discomfort. She had had a heart murmur since childhood. On physical examination, a rough grade 6/6 ejection systolic murmur was maximally audible at the second left intercostal space with a systolic thrill. The chest X-ray film showed the cardiothoracic ratio of 54% and the electrocardiogram demonstrated right ventricular hypertrophy. Calcification of the tricuspid annulus was recognized by chest X-ray films (anteroposterior and lateral views), M-mode and cross-sectional echocardiograms and the computed tomogram (CT) of the chest. Cardiac catheterization revealed the presence of valvular pulmonary stenosis and atrial septal defect. These findings were confirmed by surgical operation. Since the first description of Paktovskii in 1960, nine cases of calcification of the tricuspid annulus were reported, but no case has been described in the Japanese literature. Contrary to the mitral annulus, the echocardiographic and computed tomographic features of the calcification of the tricuspid annulus has not been reported previously. In this paper, we reported a middle aged patient with circumferential calcification of the tricuspid annulus in association with severe pulmonary stenosis and atrial septal defect, and the features of the echocardiogram and CT images were illustrated.

Calcinosis↗
PubMed1983

[Correlation between the movement of trophoblast cells invading the implantation site and the microfilament system--with special reference to the nidation site on day 15 post-coitus].

Trophoblast cells invading into decidual tissue of implantation sites of 21 cases in early stage of gestation were morphologically studied in order to clarify the correlation between integrity of the microfilament system and the various biological statuses. Especially, trophoblast cells of ovum at 15 day post coitus were mainly analyzed, since the migrating direction of the cells could be easily identified. 1. Syncytiotrophoblast cells migrating to maternal vessel were in slender shape toward the vessel. Thin and thick filaments connecting to dense body in tip of the cell run parallel with the cell axis. Thus, it is suggested that trophoblast cell migrates in decidual tissue by the joint work of its own actin and myosin in the tip of the cell. 2. Trophoblast cells making close contact with maternal cell such as endothelial cell, decidual cell and gland cell were relatively stable. The cells mainly put into action to project the cytoplasmic processes by thin filament, beneath the cytomembrane, running parallel with the cytomembrane and by thin filament, in the cytoplasmic process, running parallel with the axis of the cytoplasmic process in order to exchange information with maternal cell or to destroy the maternal cell.

Cell Movement↗
PubMed1982

Effect of three angiotensin II antagonists, [Sar1, Thr8]-, [Sar1, Ile8]- and [Sar1, Ala8]angiotensin II on blood pressure and endocrine factors in normal subjects.

The biological effects of 1-Sarcosine, 8-Threonine angiotensin II ([Sar1, Thr8]ANG II) on blood pressure, plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were investigated in six normal subjects on an unrestricted diet, and compared with those of 1-Sarcosine, 8-Isoleucine ANG II ([Sar1, Ile8]ANG II) and 1-Sarcosine, 8-Alanine ANG II ([Sar1, Ala8]ANG II). All three ANG II analogues (AIIA) showed agonistic pressor activity, that of [Sar1, Ile8]ANG II being greater than that of [Sar1, Thr8]ANG II or [Sar1, Ala8]ANG II. The antagonistic effect of [Sar1, Thr8]ANG II on blood pressure was less than [Sar1, I1e8]ANG II or [Sar1, Ala8]ANG II. Both [Sar1, Ile8]ANG II and [Sar1, Ala8]ANG II increased PAC and blocked the steroidogenic action of ANG II, while [Sar1, Thr8]ANG II showed little effect on PAC. All three AIIA caused similar suppression of PRA and showed no inhibitory effect on the decrease in PRA produced by ANG II. These results indicate that [Sar1, Thr8]ANG II is an AIIA with weak agonistic pressor action and that it has vascular selective properties. It is also suggested that ANG II receptors in a variety of target organs are heterogeneous.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1982

Responses of active and inactive plasma renin and changes in urinary kallikrein and plasma prekallikrein to various conditions in normal subjects.

Little is known about changes in inactive plasma renin in various conditions or the in vivo activation mechanism of inactive renin. The effects of various factors known to stimulate or suppress renin release on active and inactive PRA were examined in normal subjects. Inactive PRA was determined as the difference between the total PRA after trypsin activation and active PRA. Concurrent measurements of urinary kallikrein excretion and plasma prekallikrein activity were performed to assess the possible role of renal or plasma kallikrein in in vivo activation of inactive renin. Short term stimulation with iv furosemide and ambulation, infusion of isoproterenol, and administration of captopril increased active PRA, but had little or no effect on inactive PRA. Sodium restriction and sodium loading, each for 4 days, induced parallel changes in active and inactive PRA. The administration of propranolol for 4 days decreased active PRA but did not change inactive PRA. There were no significant correlations between the changes in urinary kallikrein excretion and those in active PRA or in the proportion of active to total PRA after any short term treatments, except furosemide administration. Plasma prekallikrein activity was correlated with the proportion of active renin only during the long term sodium balance study. The present data suggest that the mechanisms ofr the control of inactive and active renin are different. Neither renal nor plasma kallikrein seems to be consistently involved in the in vivo activation of inactive renin.

Adult↗
PubMed1982

[Changes of blood pressure and regional blood flow in SART rats and drug actions on these changes (author's transl)].

In order to investigate the function of the circulatory system in SART rats, systolic blood pressure and regional arterial blood flow were examined. It was found in SART stressed rats that the blood pressure was about 10 mmHg lower than that of the non-stressed group on the 6th day of stressing and after stressing, and such low blood pressure was maintained for several days. SART rats showed a decrease in the average blood flow value in the common carotid artery, increases in the average and instantaneous maximum blood flow values in the superior mesenteric artery, and the instantaneous maximum blood flow value in the abdominal aorta had a tendency to increase, though little changes were observed in the renal and the femoral arteries. It was suggested by flow contours that there was hardening in the vessel walls of the common carotid artery and the abdominal aorta, and softening in the superior mesenteric artery. SART stress-induced hypotension was further decreased by a single dose of guanethidine, clonidine, or hydralazine, but not by neurotropin. Continuous preadministration of neurotropin prevented the SART stress-induced hypotension and changes in blood flow. From the above mentioned results, the sympathetic nerve may be thought to be decreased in tension, or be depressed, in the circulatory system of SART rats.

Animals↗
PubMed1982

[Changes of the function of the heart of SART stressed (repeated cold stressed) mice and the action of neurotropin on these changes].

Electrocardiography (ECG) was performed for SART stressed (repeated cold stressed) mice which had changes in blood pressure and blood flow to examine the effects of this treatment on heart function. In the ECG of mice subjected to SART stress for 5 days, potentiations of the R and T voltage, a shortening of the PQ interval, a prolongation of the QRS interval, and a slight increase of the heart rate were observed; and such changes in the ECG were maintained for several days. Recovery from all these changes was observed after a single dose or consecutive administration of propranolol. From these results, it is considered that sympathetic nerve activity may be increased in the function of the heart in SART stressed mice, as contrasted to the partial vagotonia in the duodenum. Neurotropin (NSP), a nerve sedative, was then administered to mice once daily for 5 days during the sart stress. NSP prevented the changes of the PQ and QRS interval in SART stressed mice, but could not prevent the potentiation of the R and T voltage and the heart rate increase. In particular, the potentiations of the R and T voltages were thought to be induced by the increase of sympathetic nerve activity; therefore, it is thought that NSP may not have direct actions at least on the sympathetic nerve sites in autonomic nervous systems.

Animals↗
PubMed1982

Teratological studies on collagen wound dressing (CAS) in mice.

We subcutaneously injected collagen wound dressing (CAS) extracts equivalent to the area covering human body surface by 35 and 70%, respectively, into mouse dams from days 6 to 15 of pregnancy. No toxicity was observed in dams and no external, skeletal and visceral anomalies related to CAS treatment were observed in fetuses. It is, therefore, concluded that CAS extracts produces no teratogenesis after subcutaneous injection during organogenesis in mice.

Abnormalities, Drug-Induced↗
PubMed1982

The seasonal variation of blood pressure in patients with essential hypertension.

We examined the role of dietary electrolytes and humoral factors in causing seasonal changes in blood pressure. Normal subjects had no seasonal difference in blood pressure, although urinary sodium and norepinephrine were significantly higher in winter than in summer. In patients with essential hypertension blood pressure, urinary sodium and norepinephrine excretion and plasma norepinephrine concentration were significantly higher in winter. Plasma renin activity, plasma and urinary aldosterone and urinary kallikrein excretion were not significantly different between the two seasons in both normal subjects and hypertensive patients. In conclusions, the blood pressure of patients with essential hypertension has a seasonal variation with higher pressures in the winter than in the summer. Increased sympathetic nervous activity and an increased load of sodium presented to the kidney for excretion may be contributing factors in the rise in blood pressure in winter in patients with essential hypertension.

Adult↗
PubMed1982

Familial Bartter's syndrome.

Two sisters were found to have Bartter's syndrome. Both had hypokalemia, hyperreninemia, normal BPs, and decreased pressor responses to angiotensin II. During a water diuresis, patient 1 had an abnormally low distal tubular fractional reabsorption of chloride initially, but this normalized after hypokalemia was corrected for one year. Patient 2 had no demonstrable defect in chloride transport. Hypokalemia in Bartter's syndrome may be caused by some hereditary mechanisms other than defective reabsorption of chloride in the distal tubules.

Absorption↗