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Biomedical subjects

T Higa

Publications and source records attributed to T Higa.

135 records · Page 8Linked to original sources
PubMed1981

Metabolic detoxication of bis-(2-hydroxy-3, 5-dichlorophenyl)-sulfoxide in man.

The metabolic detoxication of bis(2-hydroxy-3, 5-dichlorophenyl)sulfoxide (BTS) in man was investigated. Bis(2-hydroxy-3, 5-dichlorophenyl)sulfide (BT) was identified in beta-glucuronidase treated urine following the administration of BTS by thin-layer chromatography, gas chromatography, ultraviolet spectrum and quantitative analysis. No other metabolites were detectable. BT-glucuronide was also identified in urine. It was assumed that BTS was reduced to BT and successively conjugated with glucuronide in man, and excreted as BT-glucuronide in the urine.

Antiplatyhelmintic Agents↗
PubMedDate not supplied

Suppressive effect of captopril on platelet aggregation in essential hypertension.

Effects of captopril on platelet aggregation were studied in 12 essential hypertensive subjects. At the same time, the effects of captopril and angiotensin II on platelet aggregation in vitro were examined in 20 volunteers. A 50-mg oral dose of captopril was administered daily to hypertensive subjects for 2 weeks; the dose was then increased to 100 mg daily for the next 2 weeks. Values of platelet aggregation induced by ADP, epinephrine, collagen, and arachidonic acid before captopril treatment were 71.9 +/- 4.5, 77.3 +/- 4.2, 72.4 +/- 4.1, and 70.8 +/- 4.3% (mean +/- SE), respectively. Two weeks after daily administration of 50 mg captopril, these values were 56.7 +/- 4.5, 50.8 +/- 7.6, 64.0 +/- 4.6, and 60.9 +/- 3.9%, respectively, with significant reduction of platelet aggregation (p less than 0.001, p less than 0.01, p less than 0.01, and p less than 0.005, respectively). Daily administration of 100 mg captopril also had a significant suppressive effect on platelet aggregation. Changes of platelet count and serum lipids were not significant. In vitro, captopril and angiotensin II added to platelet-rich plasma had no effect on platelet aggregation. These results show that the suppressive effect of captopril on platelet aggregation is a secondary action in vivo.

Aged↗
PubMedDate not supplied

Haemodynamic and hormonal effects of prazosin on head-up tilt in essential hypertensive patients: comparison with those of propranolol.

To evaluate the haemodynamic and hormonal effects of prazosin, head-up tilt was performed in 10 essential hypertensive patients, and these effects of prazosin on the tilt were compared with those of propranolol. The tilts were performed in control phase and the last days of treatment for two weeks with propranolol (90 mg/day) or prazosin (3-6 mg/day). Each drug significantly lowered the mean blood pressure at rest, and also suppressed its rise on the tilt. Heart rates were significantly increased by the tilt in the control phase, in the propranolol phase and in the prazosin phase. Cardiac index was significantly reduced by the tilt from 2.66 (s.e.m. = 0.22) 1/min per m2 to 2.08 (s.e.m. = 0.20) in the propranolol phase. However, there were not significant changes in other phases. Total peripheral resistance indices were significantly increased by the tilt in all three phases. Plasma renin activity and plasma aldosterone were significantly increased by the tilt from 2.14 (s.e.m. = 0.47) ng/ml per h to 2.46 (s.e.m. = 0.54) and from 50.6 (s.e.m. = 12.9) pg/ml to 74.9 (s.e.m. = 14.9) respectively, in the control phase. And they were also significantly increased from 1.06 (s.e.m. = 0.29) to 1.65 (s.e.m. = 0.45) and from 41.4 (s.e.m. = 16.3) to 54.0 (s.e.m. = 17.4) in the prazosin phase. There were no significant increases during the administration of propranolol. We observed that prazosin did not alter heart rate and cardiac index, but suppressed the renin-angiotensin system at rest. It is suggested that prazosin did not influence haemodynamic and hormonal responses to the tilt.

Aged↗
PubMedDate not supplied

Distribution of the blood flow supplied by the vertebral artery in humans as assessed by emission CT.

Though unilateral blood distribution of the vertebral artery has not been studied in humans, it is significant when considering the ischemic events especially embolic occlusion in vertebrobasilar system. To clarify the blood distribution, Krypton-81m was continuously infused into the vertebral arteries of 10 patients. Radioactivity was recorded by a rotating gamma camera. The perfusion images, reconstructed by computer in the transaxial plane, were classified according to whether the distribution was equal, or predominantly unilateral. Overlapping of blood supply from each vertebral artery was studied. In addition, the perfusion from one of the vertebral arteries revealed four distribution patterns with respect to laterality. A) ipsilateral; B) contralateral; C) bilateral; D) mosaic. Images obtained following perfusion of the vertebral artery show less uniformity compared to that of the internal carotid artery, suggesting a complicated vascular supply of the vertebral basilar territory. This complex distribution can be classified by the use of continuous infusion of Krypton-81m.

Adult↗
PubMedDate not supplied

A study of regional cerebral blood flow and hemodynamics in cerebrovascular diseases by selective continuous infusion of Kr-81m.

A tomographic study of regional cerebral blood flow and hemodynamics was performed on 25 patients with cerebrovascular diseases by selective continuous infusion of krypton-81m (Kr-81m). Kr-81m single photon emission computed tomograms were superimposed on X-ray computed tomograms to assess topographically the perfusion of the entire brain. Study of cerebrovascular diseases using this method showed: (1) regional cerebral blood flow change; (2) perfusion distribution change; (3) the route by which blood reached the brain or the obstructed artery proximal to the circle of Willis; (4) development of a collateral system and its actual function; and (5) efficacy of surgical bypass after extracranial-intracranial anastomosis. This method is especially useful in hemodynamic assessment in patients with ischemic cerebrovascular disease.

Adult↗