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Biomedical subjects

T Hata

Publications and source records attributed to T Hata.

At least 577 records · Page 32Linked to original sources
PubMed1981

Hormonal responses to long-term converting enzyme inhibition in hypertensive patients.

Captopril was given alone and in combination with diuretics to 49 patients with hypertension for 1 to 12 mol Within 2 mo blood pressure reduction correlated with pretreatment plasma renin activity and response to the infusion of angiotensin II antagonist, but these effects were not present at 4 mo. Plasma and urinary aldosterone were suppressed but serum converting enzyme activity, plasma bradykinin, kallikren, and prostaglandins (E and F) were in the normal range effect of captopril. Despite sustained reduction of blood pressure, plasma catecholamines were not elevated and urinary catecholamines were suppressed in patients on captopril alone. It is concluded that another mechanism, such as enhancement of renal or local kinin-prostaglandin system, as well as suppression of the renin-angiotensin-aldosterone system may be involved in the long-term efficacy of captopril. Sympathetic activity may also be depressed and contribute to the hypotensive effect.

Adolescent↗
PubMed1981

Effect of age on active and inactive plasma renin in normal subjects and in patients with essential hypertension.

The effect of age on the levels of active and trypsin-activatable inactive plasma renin was examined in 41 normal subjects and 54 patients with essential hypertension, during recumbency and after stimulation with furosemide and ambulation. Active renin levels in supine subjects and patients decreased with age. Inactive renin levels did not change with age in normal subjects, whereas in hypertensive patients they decreased with age. Following stimulation with furosemide and ambulation, the levels of active renin increased but the responsiveness to stimulus decreased with age in both groups. In contrast, inactive renin levels slightly increased after furosemide administration and ambulation, resulting in increased proportion of active to total renin. These data show that an acute stimulation with furosemide and ambulation affects mainly the active form of plasma renin, and the effect of age on inactive plasma renin in normal subjects may be different from that in patients with essential hypertension.

Adult↗
PubMed1981

The effect of aging on urinary kallikrein excretion in normotensive subjects and in patients with essential hypertension.

The effect of aging on urinary kallikrein excretion (UkalV) was investigated in 54 normal subjects, 11-88 yr old, and 37 patients with essential hypertension, 17-82 yr old. Urinary sodium, potassium, and aldosterone excretion (U(Ald)V) were also measured in these subjects. Urinary sodium and potassium excretion in both normal subjects and hypertensive patients did not significantly change with aging. In normal subjects, U(kal)V (r = 0.45; P less than 0.001) and U(Ald)V (r = 0.58; P less than 0.01) significantly decreased with increasing age. U(kal)V was positively correlated with U(Ald)V (r = 0.44; P less than 0.001). In contrast, the hypertensive patients had a significant decrease with age in U(Ald)V (r = -0.36; P less than 0.05), but no significant age-related change in U(kal)V. No significant correlation between U(kal)V and U(Ald)V was observed in the hypertensive patients. In individuals less than 60 yr old, there was no significant difference in U(kal)V values between normal subjects and hypertensive patients. Hypertensive patients more than 60 yr old excreted more urinary kallikrein than normal subjects of the same age group (P less than 0.05). In conclusion, the age-related decrease of U(kal)V in normal subjects may be due to the reduced activity of the renin-angiotensin-aldosterone system. It remains to be elucidated whether the absence of the age-related decrease in U(kal)V in hypertensive patients is related to the pathogenesis or pathophysiology of essential hypertension.

Adolescent↗
PubMed1981

Experimental pharmacological study on partial sympathicotonia in restraint and water immersion stressed animals.

In order to obtain evidences supporting the previous suggestion that restraint and water immersion stressed (RWIS) animals are possibly in the state of partial sympathicotonia, further investigations have been carried out. 1) In the experiment on the influence from the adrenal, the preadministration of dexamethasone, spironolactone or metopirone did not affect the enhancement of response to acetylcholine (ACh) of the duodenum isolated from RWIS mice, while adrenalectomy inhibited both the enhancement of response to ACh and the reduction of response to noradrenaline (NA) of isolated duodenum and vas deferens of RWIS mice. The potentiation of the response to ACh of the duodenum isolated from the adrenalectomized RWIS mouse, on the other hand, was little affected by the pretreatment of dexamethasone. These results suggest that in the RWIS animal the influence from the adrenal medulla is greater than that from the adrenal cortex. 2) In the experiment on the influence from the autonomic nervous system, the treatment of RWIS mice with an adrenergic neuron degenerating agent to cause chemical denervation was found to suppress the potentiation of the response to ACh of isolated duodenum and vas deferens, suggesting the participation of the adrenergic neuron. A vagotomy showed little effect on responses either to ACh or NA of isolated duodenum and vas deferens from RWIS mice. A sympathectomy, however, suppressed these changes in responses, particularly reduction of response to NA was markedly inhibited to the normal level. These findings indicate that the excessive sympathicotonic state in the RWIS animal was remitted by sympathectomy. It may be concluded that the results of present investigations utilizing adrenalectomy, vagotomy and sympathectomy may present evidences for the previous suggestion that the RWIS animal might be in the state of partial sympathicotonia.

Adrenal Cortex Hormones↗
PubMed1981

The effect of age on active and cryoactivatable inactive plasma renin in normal subjects and patients with essential hypertension.

The effect of age on active and cryoactivatable inactive plasma renin levels was examined in 58 normal subjects and 58 patients with essential hypertension during recumbency and after stimulation with furosemide and ambulation. Active renin levels declined with age in both supine subjects and patients. Inactive renin levels did not change with age in normal subjects, while in hypertensive patients they decreased with age. Following stimulation with furosemide and ambulation, the levels of active renin increased but its responsiveness to the stimulus decreased with age in both groups. In contrast, inactive renin was not significantly influenced by furosemide administration and ambulation. These data show that an acute stimulation with furosemide and ambulation affects mainly the active form of plasma renin, and that the effect of age on inactive plasma renin in normal subjects may be different from that in patients with essential hypertension.

Adolescent↗
PubMed1981

Effects of exogenous stimuli and centrally acting drugs on galvanic skin responses in rats.

Effects of physical stimulus and psychic stimulus on the galvanic skin response (GSR) in rats were evaluated. A significant change in the GSR was observed after exposing the rat to the noise of hand-clapping, and introducing another rat into the cage. The latter stimulus had a much greater effect than the former. Changes in GSR were measured after various animals were introduced into the test cage. A shift in the GSR in intrusion of guinea pig or rabbit was significantly greater than that in intrusion of Wistar rat, but no difference was observed in intrusion of rat and mouse. Changes in GSR were studied by introducing another animal into the test cage containing a single rat (isolated state) or a pair of rats (grouped state). The change in the GSR in the grouped state was generally smaller than that in the isolated state, but there was no difference in the score between these states when a rabbit was introduced. When the effect of drugs on changing of GSR was investigated, we found that elevation of GSR value, as induced by exogenous stimuli, was inhibited by tranquilizers such as chlorpromazine, carpipramine and diazepam. These tranquilizers in a remarkably small dose had an apparent effect on the psychic, mutual relation in GSR test in rats.

Animals↗
PubMed1981

A case of normoreninemic, normotensive primary aldosteronism associated with essential hypertension and nephrocalcinosis.

A 36-year-old female case of normotensive normoreninemic primary aldosteronism with persistent hypokalemia and nephrocalcinosis is reported. She was referred to us for episodes of sudden muscle weakness during 8 years prior to admission. On the first day of admission, her blood pressure was 174/104 mmHg. On the second day of admission blood pressure normalized to 120/80 mmHg. Both of her parents were hypertensive. Arterial blood gas analysis showed metabolic alkalosis. Except an impaired urine concentration ability, renal functions were normal. Intravenous pyelogram showed numerous granular calcifications. Basal plasma renin activity was 1.0 approximately 1.5 ng/ml/hr and increased by sodium depletion. Plasma aldosterone concentration was 70 approximately 80 ng/dl and did not respond to various stimulations. Blood pressure was dependent on sodium balance. It fell on salt restriction and rose on salt loading. Blood pressure responses to vasoactive hormones were normal. Circulating plasma volume was within normal range. After removal of an adrenal adenoma, there was mild fall of blood pressure, serum potassium returned to normal level and plasma renin activity increased slightly. Histologically, there was renal tubular calcifications, and juxtaglomerular apparatus was normal. Blood pressure was elevated to 160/100 mmHg when patient was followed at out-patient clinic after discharge. We concluded that she had essential hypertension associated with primary aldosteronism. Although sodium loss and an increase in urinary kallikrein were found, they did not seem to be the cause of normoreninemic normotensive state of this patient, and the pathogenesis remains to be elucidated.

Adrenal Gland Neoplasms↗
PubMed1981

Methylation of 5'-5' confronting dinucleotides by vaccinia associated enzyme system.

Methylation of a series of the 5'-5' confronting dinucleotides containing various number of phosphates was examined by the use of virion enzyme system of vaccinia virus. Methylation was absolutely dependent on the number of interposed phosphate groups between 5'-5' confronting dinucleotides, showing maximum efficiency in the 3 phosphate compound corresponding to the blocked 5'-terminus (cap) of an eukaryotic mRNA. Methylation, if any, occurred only at the 7-position of guanine residue, but not at the 2' position of ribose moiety.

Dinucleoside Phosphates↗
PubMed1981

Contact patterns between cytotrophoblast and decidual cells in human implantation site.

To elucidate the mechanism of trophoblastic invasion, implantation sites removed from human uteri of early gestational stages of 7 to 10 week were investigated by electron microscopy. Almost all trophoblast cells which penetrated the fibrinoid layer and invaded into decidual tissue were cytotrophoblast cells, and abundant close-contacts between the cytotrophoblast and decidual cells were recognized in this site. The close-contact patterns which were composed of simple apposition, cytoplasmic projection from both cells and mixture of those without fusion were classified into five types. At the time of close-contact, the decidual cells showed the altered structures in various degrees, but never did they alter so strongly as to appear to have died completely. Thus, it is deduced that the influence from cytotrophoblast cells did not cause the destruction of the decidual cells but only biological inactivation of the cells. It is of great significance to the immunological problem between fetus and mother that the cytotrophoblast cells which are fetal epithelial cells can be in close-contact with decidual cells which are maternal stromal cells. Further confirmation relating to the production and transcellular transfer patterns of the information materials should be awaited in future.

Cell Communication↗
PubMed1981

[An ultrastructural study of penetration and replacement process by trophoblast cell into human maternal vessel (author's transl)].

To elucidate the mechanism of trophoblastic penetration into maternal vessels and the function of the trophoblast replacing the endothelium, feto-maternal junctional zone (FMJZ) removed from human uteri in early gestational stages of 4 to 11 weeks were morphologically investigated. The trophoblast cells which can approach to or penetrate the maternal vessels and can replace the endothelial cell were only syncytiotrophoblast cells. Since microfilaments aggregated in bundle in cytoplasm of the syncytiotrophoblast cells which are approaching to the maternal vessel inserted into dense bodies or dense patches, it is considered that the microfilaments are composed of thin filaments mainly like in smooth muscle cell. Degranulation of rER and lysosomal structure or aggregation of microfilaments are occurred in endothelial cells penetrated or closely contacted by field horsetail-like cytoplasmic processes of syncytiotrophoblast cell, respectively. It is possible that the syncytiotrophoblast cell and maternal endothelial cell have similar origin, since both cell can be in close contact with tight junction and simple apposition like intrinsic endothelial junction.

Blood Vessels↗
PubMed1981

Phagocytosis of human cytotrophoblast cell invading into decidual tissue in early stage of gestation.

To elucidate the mechanism of trophoblastic invasion, further electron microscopic observation of human implantation sites, described in a preliminary paper, were performed. The cytotrophoblast cells invaded decidual tissue have taken in many cells and absorbed many materials. In this paper, the authors specifically report the phagocytotic function of the cytotrophoblast cell. It was clarified by criteria, described in preliminary papers, for judgement of cells composing the feto-maternal junctional zone that almost all cells phagocytized by the cytotrophoblast cells were decidual cells which showed significant ultrastructural changes in various degrees; some cells still had intrinsic features by which the cells could be clearly identified as decidual cell, and some cells were considered as a strongly altered degenerated decidual cells. Moreover, even though these phagocytized cells had not so many lysosome that these cells can autolysis, the cytotrophoblast cells had many lysosome having strong activity of acid phosphatase. After the cytotrophoblast cells contact decidual cells by means of many patterns, the cytotrophoblast cells can phagocytized the inactivated cell and can intracytoplasmically digest the cell actively.

Decidua↗