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Biomedical subjects

T Takada

Publications and source records attributed to T Takada.

At least 271 records · Page 15Linked to original sources
PubMed1986

[Antihypertensive effects of SA446, hydralazine and the combination on renal hypertensive rats and spontaneously hypertensive rats by long-term treatment].

SA446 [(2R, 4R)-2-(o-hydroxyphenyl)-3-(3-mercaptopropionyl)-4- thiazolidinecarboxylic acid] (30 mg/kg/day), an orally active angiotensin-converting enzyme inhibitor, lowered significantly indirect systolic blood pressure (SBP) of 2-kidney, 1-clip renal hypertensive rats (RHR) by consecutive oral administration over a 14 week period. Daily oral dosing of hydralazine (2 mg/kg/day) for 14 weeks had little or no effect on SBP, but potentiated the antihypertensive effect of SA446. One to two weeks after discontinuation of the drugs, SBP in SA446 and the combination groups returned to the control level. Survival rates were 64%, 30% in the control and hydralazine group, respectively, but no death was observed in the SA446 group and the combination group throughout the administration period. Twenty-four hour urine volume and water intake tended to increase in the hydralazine group through the administration period, but increased apparently in the SA446 group and the combination group after discontinuation of the drugs. Daily oral dosing of SA446 (45 mg/kg/day) for over 16 weeks completely prevented the development of hypertension in spontaneously hypertensive rats (SHR). Daily oral dosing of hydralazine (2 mg/kg/day) similarly prevented the development. The combined effect with SA446 and hydralazine on the development was also observed. SBP in the SA446 group and the combination group increased gradually after discontinuation of the drugs, but were maintained at a low level as compared with the control group 3 weeks after discontinuation, while hydralazine gave a rapid return. No influences were observed in 24 hr-urine volume and water intake during and after the administration period in SHR.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Mercaptopropionic Acid↗
PubMed1986

[Combined effect of (2R, 4R)-2-(o-hydroxyphenyl)-3-(3-mercaptopropionyl)-4-thiazolidinecarbo xyl ic acid (SA446) with hydrochlorothiazide or propranolol on development of hypertension in spontaneously hypertensive rats (SHR) by long-term administration].

Effect of long-term oral administration of the converting enzyme inhibitor (2R, 4R)-2-(o-hydroxyphenyl)-3-(mercaptopropionyl)-4-thiazolidinecarboxylic acid (SA446) in combination with hydrochlorothiazide or propranolol on the development of hypertension was examined in spontaneously hypertensive rats (SHR). The development of hypertension in SHR was markedly suppressed by the treatment with SA446 (45 mg/kg, p.o.) for 17 weeks from 8 weeks of age, the pre-stage of hypertension. Long-term administration of hydrochlorothiazide (20 mg/kg, p.o.) also showed an obvious antihypertensive effect, but the effect was less potent than that of SA446. On the other hand, propranolol (20 mg/kg, p.o.) showed a slight or little antihypertensive effect. The combined administration of hydrochlorothiazide and SA446 produced a more potent antihypertensive effect than the administration of SA446 alone. On the other hand, the combined use of propranolol had no influence on the antihypertensive effect of SA446 by long-term administration in SHR. Plasma renin activities measured after 17 weeks treatment of the drugs indicated that the renin-angiotensin system was activated by hydrochlorothiazide. These results suggest that the antihypertensive effect of long-term administration of SA446 in SHR is enhanced by the combined administration of diuretics such as hydrochlorothiazide, which activates the renin-angiotensin system.

3-Mercaptopropionic Acid↗
PubMed1986

Angiotensin converting enzyme (ACE) in the kidney: contribution to blood pressure regulation and possible role of brush-border ACE.

With regard to the concept of the local action of the renin angiotensin system (RAS) involved in blood pressure regulation, the presence of angiotensin converting enzyme (ACE) in a variety of organs suggests that locally produced angiotensin II (ANG II) shares, at least to some extent, the actions of this peptide on respective target organs of ANG II. However, renal ACE is less well understood for its relationship between blood pressure and enzyme activity. In our present studies, with a single oral administration of enalapril to spontaneously hypertensive rats, the inhibition of renal cortical and aortic ACE, but not plasma ACE, coincided with a reduction in blood pressure. Development of high blood pressure in stroke-prone, spontaneously hypertensive rats (SHRSP) from 7 to 22 weeks of age was accompanied by an increase in ACE activity in the renal cortex. Aortic and pulmonary ACE also tended to increase with age, but was less prominent. Isolated brush-border membranes contained abundant ACE, both in Wistar-Kyoto rats and SHRSP, and the levels of ACE in renal cortical homogenates closely correlated to the levels of brush-border ACE. Thus, changes in renal cortical ACE activity in response to the ACE inhibition and in cases of SHRSP in relation to aging are apparently associated with changes in blood pressure. It is likely that renal cortical ACE activity reflects the enzyme activity in the brush borders. Thus, brush-border ACE should probably be taken into account when discussing possible roles of renal ACE.

Aging↗
PubMed1985

A case of pericholecystic abscess diagnosed by ultrasonography.

Pericholecystic abscess is a serious complication of cholecystitis. Though preoperative diagnosis is easy by gray-scale ultrasonography, there has been no case reported in which the communication between pericholecystic abscess and the gallbladder was demonstrated ultrasonically. We experienced a case in which the communication route between a pericholecystic abscess and the gallbladder was successfully demonstrated by a real-time electric linear scanner. Furthermore, the abscess was successfully treated by percutaneous drainage following ultrasonically guided puncture. This success demonstrates that ultrasonography by a real-time scanner can be effective for diagnosis and treatment of acute cholecystitis and pericholecystic abscess.

Abscess↗
PubMed1985

Real-time analysis of the change in arterial oxygen tension during endotracheal suction with a fiberoptic bronchoscope.

An intra-arterial Clark-type polarographic oxygen electrode was used with a fiberoptic bronchoscope for real-time analysis of the PO2 change during 1 min of suction in patients spontaneously breathing oxygen. There was a strong correlation between values obtained from the intra-arterial electrode (PiO2) and those from blood samples (PaO2), before and at the end of suction; the PiO2/PaO2 ratio was close to one. Continuous PiO2 recordings during suction without supplemental oxygen showed little change in the early period of suction, followed by a steep drop continuing even after suction. This drop in PiO2 was partially attenuated by providing oxygen with high-frequency jet ventilation and was almost completely attenuated by the use of a suction adaptor. Changes in the inspired oxygen concentration indicated the importance of keeping this variable constant during suction to prevent hypoxemia.

Adult↗
PubMed1985

Effects of angiotensin I-converting enzyme inhibitor (SA-446) on renal function in dogs.

The effects of an orally active inhibitor of angiotensin-converting enzyme (SA-446) on systemic arterial pressure, renal function and renin release were examined in anesthetized dogs. Intrarenal infusion of the larger dose of SA-446 (0.1 mg/min) caused an increase in RBF, urine flow and renin release and caused a fall in blood pressure. The smaller dose of SA-446 (0.02 mg/min) did not affect the blood pressure, but it increased the urine flow. However, the same dose of SA-446 in combination with probenecid caused a significant fall in blood pressure. The potentiation of SA-446 with probenecid may be explained by the elevation in plasma SA-446 concentration via the inhibition of its tubular secretion by probenecid.

3-Mercaptopropionic Acid↗
PubMed1985

Plasma prolactin levels in patients with essential hypertension, malignant hypertension and secondary hypertension.

Plasma prolactin level and plasma renin activity were determined in normal subjects and patients with low and normal renin essential hypertension, renal hypertension, renovascular hypertension, primary aldosteronism, Cushing syndrome, pheochromocytoma and malignant hypertension. In both normal subjects and the normal renin essential hypertensives, plasma prolactin was significantly higher in females than in males. Plasma prolactin was also significantly higher in the normal renin essential hypertensives than in normal subjects of both sexes, while no significant difference was found between the low renin group and normal subjects of either sex. A significantly positive correlation was observed between plasma renin activity and the plasma prolactin level in male essential hypertensives, but not in females. Although no significant difference in plasma prolactin level could be detected between patients with secondary hypertension and normal subjects, this level was significantly higher in malignant hypertensives than in normotensives. From these results, it was shown that significant differences of plasma prolactin levels exist between normal renin essential hypertensives, and low renin essential hypertensives or normal subjects, and that these differences may partly depend on renin status which might be related to the central dopaminergic activity. In malignant hypertensives, the high level of plasma prolactin may be caused by diminished renal function, but the suppression of central dopaminergic activity cannot be excluded in the mechanism of plasma prolactin increment.

Adolescent↗
PubMed1985

The effect of blood volume changes accompanying isotonic circumstances on plasma antidiuretic hormone levels in normal subjects.

Changes in plasma ADH levels were investigated in human male subjects whose blood volume was altered under isotonic circumstances. Blood volume was reduced by ambulation and increased by isotonic saline infusion in an overnight dehydrated state, and determinations were made on plasma ADH levels, plasma osmolality and hematocrit values. Plasma ADH levels were clearly affected by the small changes in blood volume, and significantly negative correlation was found between plasma ADH levels and the percent changes in blood volume under isotonic circumstances. From these findings, it was concluded that ADH release in human subjects is also controlled by the changes of the blood volume factor in addition to osmotic stimuli.

Adolescent↗