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Biomedical subjects

T Omae

Publications and source records attributed to T Omae.

At least 91 records · Page 5Linked to original sources
PubMed1993

Effect of reduced alcohol consumption on blood pressure in untreated hypertensive men.

Fifty-four untreated, mildly hypertensive men whose daily alcohol consumption was > or = 28 ml ethanol and who drank at least 4 times per week took part in a randomized, controlled crossover trial. The purpose of the trial was to test the effects of alcohol reduction on blood pressure. After a 2-week familiarization period, the participants were assigned to either a reduced alcohol drinking group or a usual drinking group for 3 weeks (experimental period 1). The situation was then reversed for the next 3 weeks (experimental period 2). The participants were requested to limit their daily alcohol consumption to zero or reduce it as much as possible for the reduced alcohol consumption period. The self-reported alcohol consumption was 56.1 +/- 3.6 (SEM) ml/day during the usual alcohol drinking period and 26.1 +/- 3.0 ml/day during the period of reduced alcohol consumption. Systolic and diastolic blood pressures in the intervention group were found by analysis of variance to be significantly lower (2.6-4.8 and 2.2-3.0 mm Hg, respectively) than those in the control group during experimental period 2 for systolic blood pressure and experimental period 1 for diastolic blood pressure. Significant (3.6 mm Hg) and nonsignificant (1.9 mm Hg) decreases in systolic and diastolic blood pressure, respectively, were observed. The method of Hills and Armitage was used, reducing ethanol in daily alcohol consumption by 28 ml. The lowering effect of reduced alcohol consumption on blood pressure was independent of changes in salt consumption, which were estimated by 24-hour urine collection and body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Clinical features of recurrent embolization in acute cardioembolic stroke.

BACKGROUND AND PURPOSE: Recurrent embolization is a serious problem in acute cardioembolic stroke. However, the clinical features and predisposing factors of recurrent embolization have not been fully elucidated. METHODS: Subjects were 227 consecutive patients (128 men and 99 women, aged 68.6 +/- 13.2 years) with acute cardioembolic stroke who did not receive anticoagulant therapy during the first 14 days after stroke onset. We assigned the subjects to two groups according to the occurrence or nonoccurrence of recurrent attacks within 14 days of the stroke onset. We assessed their clinical features, coagulation study results, and underlying heart disease. RESULTS: Recurrent brain or systemic embolization during the first 14 days after onset was noted in 46 patients (20.3%, group A) but not in the other 181 (group B). Recurrent embolization was more frequently noted at an early phase than at a late phase during the initial 14 days. Mortality was higher in group A (19.6%) than in group B (8.8%). The mean plasma level of antithrombin III (77.8 +/- 19.5%) at admission in group A patients was significantly lower than that in group B patients (87.9 +/- 15.5%). After admission, hematocrit decreased in group B patients but slightly increased in group A patients, in whom diuretics were more commonly used. Rheumatic heart disease and prosthetic valves, in addition to the presence of intracardiac thrombi, were seen more commonly in group A patients, whereas atrial fibrillation without organic heart disease and myocardial infarction were more frequent in group B patients. CONCLUSIONS: Low plasma levels of antithrombin III, dehydration, the use of diuretics, and the presence of rheumatic heart disease, prosthetic valves, and intracardiac thrombi seem to be predisposing factors for recurrent embolization. Immediate anticoagulation may be considered in acute cardioembolic stroke patients if such predisposing factors are demonstrated.

Aged↗
PubMed1993

The J-curve phenomenon in stroke recurrence.

BACKGROUND AND PURPOSE: The relation of poststroke blood pressure to stroke recurrence remains undetermined, and the optimal control of blood pressure has not been established. We performed the present study to resolve these issues. METHODS: We analyzed 368 stroke patients with a history of hypertension (mean age, 62 years) who were admitted within 3 months after stroke onset and observed for 6 months or more. We determined stroke recurrence rate in relation to baseline (or initial) blood pressure, mean values of poststroke blood pressure, stroke subtypes, age, antihypertensive treatment, and other clinical features. RESULTS: The recurrence rate had a J-curve relation to poststroke diastolic blood pressure but not to poststroke systolic blood pressure and baseline diastolic and systolic blood pressures. The stroke recurrence rate was 3.8% per patient-year in 94 patients who had a poststroke diastolic blood pressure of 80 to 84 mm Hg, significantly lower than the rates of 9.2% per patient-year (P < .05) and 11.4% per patient-year (P < .01) in those with a lower and higher poststroke diastolic blood pressure, respectively. The range of poststroke diastolic blood pressure accompanying the lowest stroke recurrence rate was higher in patients with atherothrombotic (85 to 89 mm Hg) than in those with lacunar infarction (80 to 84 mm Hg). Neither antihypertensive therapy nor patients' age affected this phenomenon. CONCLUSIONS: The present study suggests that lower blood pressure does not always result in favorable effects on stroke recurrence. The effects of poststroke blood pressure and antihypertensive therapy on stroke recurrence may be complicated by the J-curve phenomenon.

Aged↗
PubMed1993

Effects of dihydropyridines on cerebral blood vessels.

AIM: To evaluate the effects of dihydropyridine calcium antagonists on the cerebral circulation in stroke patients. DESIGN OF STUDIES: Mean cerebral circulation parameters were studied in chronic stroke patients with hypertension and treated acutely or chronically (2 weeks) with nicardipine or nifedipine retard. The effects of nicardipine on local cerebral blood flow were also studied in patients with a subacute brain infarction. RESULTS: Mean cerebral blood flow was significantly increased after a single oral administration of nicardipine but not after nifedipine retard. Both calcium antagonists reduced mean arterial pressure. Nifedipine retard acted mainly by reducing blood pressure and nicardipine mainly by reducing cerebrovascular resistance. CONCLUSION: Dihydropyridines have a beneficial effect in the control of hypertension in stroke patients.

Administration, Oral↗
PubMed1992

Glucagon-glucose (GG) test for the estimation of the insulin reserve in diabetes.

The residual B-cell function was examined by means of the plasma C-peptide response 6 min after a combined injection of glucagon and glucose (GG test) or conventional glucagon test (G test) in four insulin-dependent diabetic patients (IDDM group), in 18 diabetic patients treated with insulin (Insulin group), 31 treated with oral hypoglycemic agents (SU group) and 27 treated with diet only (Diet group) and in 22 borderline cases. By GG test, 6-min C-peptide values of the IDDM group were 0.27 +/- 0.05 nM (n = 4) and were significantly lower than those of the Insulin group (0.89 +/- 0.09 nM, n = 12), the SU group (1.42 +/- 0.10 nM, n = 13), the Diet group (2.47 +/- 0.22 nM, n = 11) and the borderline cases (3.38 +/- 0.22 nM, n = 11). Patients with a 6-min C-peptide concentration below 0.75 nM by GG test appeared to be insulin-requiring patients. In the G test, plasma C-peptide concentrations at 6 min were 0.35 +/- 0.08 nM in the IDDM group (n = 2), 0.72 +/- 0.20 nM in the Insulin group (n = 7), 1.08 +/- 0.09 nM in the SU group (n = 20), 1.40 +/- 0.19 nM in the Diet group (n = 17) and 2.05 +/- 0.21 nM in the borderline cases (n = 12). Some of the Diet group patients showed extremely low C-peptide responses. When comparing the GG test and G test in individual cases, a greater C-peptide response was seen with the GG test in all cases except for IDDM patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Alcohol drinking and high blood pressure: data from a 1980 national cardiovascular survey of Japan.

Many epidemiological cross-sectional studies have confirmed that alcohol drinking is related to high blood pressure. However, the impact of alcohol drinking on high blood pressure in the general population including older people has only been reported on in a few studies. The association between alcohol drinking and blood pressure or the prevalence of hypertension was examined using cross-sectional data of 4795 men and 6102 women aged 30-94, randomly selected from the Japanese population in 1980. The response rates were 74 and 84% for men and women, respectively. The prevalence of hypertension adjusted for body mass index (BMI, kg/m2) was significantly higher in everyday male drinkers than in male non-drinkers from the youngest age group (30-39 years) to oldest age group (70 years and over). A relationship between alcohol and blood pressure was found only in the youngest age group (30-39 years) of female drinkers. In each 10-year age-group of men, the BMI-adjusted systolic and diastolic blood pressures in everyday drinkers were 7-10 and 4-6 mmHg higher than those in non-drinkers. The relationship between alcohol and blood pressure in men was confirmed by multiple regression analysis adjusting for age and BMI in both younger (30-59 years) and older (60-94 years) people. The impact of alcohol drinking on blood pressure in men should be taken into account in the primary prevention of blood pressure related diseases and in the treatment of hypertension in both younger and older people.

Adult↗
PubMed1992

Angiotensin II does not increase renal prostaglandin E2 in response to pressure reduction.

Whether angiotensin II (Ang II) stimulates renal secretion of prostaglandin E2 (PGE2) synthesized in response to pressure reduction was examined. PGE2 and Ang II in aortic and renal venous plasma were measured before and during renal arterial constriction in anesthetized dogs, with or without an intrarenal arterial infusion of an Ang II antagonist, losartan potassium (1 mg/min), or saralasin (3 micrograms/min). In other anesthetized dogs, two doses of Ang II (30 and then 300 ng/min) were infused into the renal artery, and plasma Ang II levels and renal PGE2 secretion were measured. When renal perfusion pressure was reduced to 75 and 45 mm Hg by constriction, the renal secretion of PGE2 increased seven- and fourfold, respectively. Ang II levels in the renal venous plasma increased from 6.6 +/- 1.8 to 21.7 +/- 7.4 and then 48.1 +/- 15.3 pg/ml (both P less than 0.05) as the pressure decreased. Neither losartan nor saralasin suppressed the response of renal PGE2 secretion to the pressure reduction. The intrarenal infusion of Ang II (30 ng/min) elevated the Ang II level in the renal venous plasma from 9.8 +/- 4.6 to 33.7 +/- 4.2 pg/ml (P less than 0.01), but did not increase PGE2 secretion. The higher dose (300 ng/min) of Ang II increased it, but the Ang II level in the renal venous plasma was 166 +/- 63 pg/ml. These results suggest that the greater part of the increased renal synthesis of PGE2 in response to pressure reduction is not mediated by Ang II.

Angiotensin II↗
PubMed1992

Insulin insensitivity in nonobese, nondiabetic essential hypertension and its improvement by an alpha 1-blocker (bunazosin).

To investigate insulin insensitivity and its reversibility, we performed an insulin sensitivity test using the steady state plasma glucose (SSPG) method in 10 lean hypertensive subjects with normal glucose tolerance before and after treatment with alpha 1-blocker bunazosin, and 14 age body mass index-adjusted healthy control subjects. Steady state plasma glucose was significantly higher in the hypertensive subjects compared with the control group (182 +/- 10 mg/dL v 104 +/- 7, P < .01, mean +/- standard error of the mean (SEM). Steady state plasma glucose significantly decreased to 136 +/- 12 mg/dL (P < .01) after the treatment with alpha 1-blocker bunazosin, with a decrease of blood pressure. Hypertensive subjects had shown an increased area under the curve of glucose and insulin during the oral glucose tolerance test compared with normal controls. The glucose area decreased significantly, but the insulin area did not change after the treatment. There was no difference in plasma epinephrine, norepinephrine, and fractional excretion of Na between normal and hypertensive subjects both before and after treatment with bunazosin at basal and during insulin sensitivity tests (2 h). Serum total cholesterol level decreased and HDL cholesterol increased significantly after treatment with bunazosin. A significant correlation was observed between SSPG and blood pressure, but not between insulin level and blood pressure. The results indicate that insulin sensitivity is better related than hyperinsulinemia to hypertension and that this insensitivity is partially reversible by alpha 1-blocker, bunazosin.

Adrenergic alpha-Antagonists↗
PubMed1992

Effects of dietary salt on sodium-calcium exchange and ATP-driven calcium pump in arterial smooth muscle of Dahl rats.

AIM: To compare the effects of dietary salt on sodium-calcium exchange and the ATP-driven calcium pump in arterial smooth muscle between Dahl salt-sensitive (DS) and salt-resistant (DR) rats. METHODS: Aortic rings freshly excised from 16 DS rats and 16 DR rats on a low- (0.3%) or high- (8%) NaCl diet for 4 weeks were superfused with physiological saline and isometric tension was measured. In the presence of 10 mumol/l phentolamine, 10 mumol/l verapamil and 5 mmol/l caffeine, relaxation of a low-Na+ contraction was promoted by external calcium removal. RESULTS: On the high-salt diet, the rate of relaxation at 1.2 mmol/l extracellular sodium (calcium extrusion by calcium ATPase) was significantly lower in aortic rings from DS rats than from DR rats. The increase in the rates of relaxation from 1.2 mmol/l to normal (139.2 mmol/l) extracellular sodium (calcium extrusion by sodium-calcium exchange) was significantly greater with the high-salt diet than with the low-salt diet in rings from DR rats, but it was not different between the high- and low-salt diets in DS rats. The rate of increase in tonic tension by reducing extracellular Na+ from normal to 1.2 mmol/l in the presence of verapamil, caffeine and phentolamine (calcium entry by sodium-calcium exchange) was significantly lower in rings from DS rats than in those from DR rats on the high-salt diet. CONCLUSIONS: These observations suggest that the effects of dietary salt on the sodium-calcium exchange system in arterial smooth muscle differ between DS and DR rats and that calcium extrusion by the calcium pump is decreased in DS rats compared with DR rats. The lack of an increase in sodium-calcium exchange in salt-fed DS rats might lead to an elevation in cellular calcium and contribute to the mechanism of hypertension.

Adenosine Triphosphate↗
PubMed1992

Intracellular free magnesium of red blood cells in patients with renal disease.

While serum magnesium (Mg) level is increased in patients with end-stage renal disease (ESRD), it is decreased in renal transplant recipients (TR) receiving ciclosporin. This study was performed to examine the cation metabolism of red blood cells (RBC) in these patients. Intracellular free Mg was measured with 31P-nuclear magnetic resonance spectrometry, and ouabain-sensitive sodium (Na) efflux rate (Eos) was measured from the increase in RBC-Na concentration when RBC were incubated in the presence of ouabain. The ouabain-sensitive Na efflux rate constant (ERCos) was obtained by dividing Eos by RBC-Na concentration. RBC free Mg and ERCos were significantly higher in the TR group than in the ESRD group. There was a significant correlation between RBC free Mg and ERCos (r = 0.474, p less than 0.01). These results support the views that the regulation mechanism for intracellular free Mg is different from that for extracellular Mg in patients with renal disease, and intracellular free Mg modulates Na pump activity of RBC.

Adenosine Triphosphate↗
PubMed1992

Acute depressor effect of alcohol in patients with essential hypertension.

To investigate the time course of the effects of alcohol on blood pressure, we studied the response of ambulatory blood pressure, neurohumoral variables, and hemodynamics to a single moderate dose of alcohol in hypertensive patients. Sixteen Japanese men (22-70 years old) with essential hypertension who were habitual drinkers were examined under standardized conditions. On the alcohol intake day, they ingested 1 ml/kg ethanol (vodka) at dinner, and on the control day they consumed a nonalcoholic beverage. The order of the two periods was randomized. Mean ambulatory blood pressure was lower in the alcohol intake period than in the control period (125 +/- 3/74 +/- 2 versus 132 +/- 4/78 +/- 2 mm Hg, p less than 0.05), and the significant depressor effect of alcohol lasted for up to 8 hours after drinking. Blood pressure on the next day did not differ with or without alcohol intake. The acute hypotensive effect of alcohol was associated with an increase in heart rate and cardiac output and with a decrease in systemic vascular resistance as determined by echocardiography. Plasma catecholamine levels and renin activity rose significantly at 2 hours after dinner, whereas vasopressin and potassium levels fell on the alcohol day. Blood glucose and serum insulin levels were comparable between the two periods. Three patients with marked alcohol-induced flush had greater hypotensive and tachycardiac responses than those who did not show an alcohol-induced flush. The change in mean blood pressure induced by alcohol was negatively correlated with age, the baseline blood pressure, and the change in plasma norepinephrine. These results indicate that the major effect of acute alcohol intake is to lower blood pressure through systemic vasodilatation in hypertensive subjects. Ambulatory blood pressure monitoring may be useful for assessing blood pressure in habitual drinkers.

Adult↗
PubMed1992

Ultrasonic evaluation of the site of carotid axis occlusion in patients with acute cardioembolic stroke.

PURPOSE: We performed the present study to determine whether the site of cardioembolic occlusion in the carotid axis could be identified by end-diastolic velocity measurements of the common carotid arteries. SUMMARY OF REPORT: Using duplex carotid ultrasonography, we measured the flow velocity in the common carotid arteries and calculated the side-to-side ratios of the end-diastolic velocity (ED ratio; the end-diastolic velocity of the nonaffected side divided by that of the affected side) in 46 patients with acute cardioembolic stroke. The velocity on the faster side was divided by the slower velocity to obtain the normal values of ED ratio in 30 controls. The ED ratios were compared with the angiographic findings, in which unilateral intracranial internal carotid artery occlusion was present in 20 patients (IC group), occlusion of the horizontal segment of the middle cerebral artery was present in 16 patients (M1 group), and branch occlusion of the middle cerebral artery was present in 10 patients (MBr group). The ED ratios of the control group were less than 1.3; those of the MBr group generally less than 1.3; the IC group greater than 4.0, except in two patients with severe cerebral edema; and those of the M1 group between 1.3 and 4.0. Therefore, the IC group was easily distinguished from the other groups by an ED ratio greater than or equal to 4.0, with an accuracy of 97%, and the M1 group by an ED ratio greater than or equal to 1.3 and less than 4.0, with an accuracy of 93%. CONCLUSIONS: We found the ED ratio useful to identify internal carotid artery and middle cerebral artery occlusion in patients with cardioembolic stroke unless severe cerebral edema was present.

Arterial Occlusive Diseases↗
PubMed1992

Cheiro-oral syndrome due to lesions in the corona radiata.

BACKGROUND AND PURPOSE: We describe three patients with cheiro-oral syndrome caused by a small lesion in the corona radiata confirmed by high-resolution magnetic resonance imaging. CASE DESCRIPTIONS: Case 1: A 56-year-old hypertensive man who developed hypesthesia and paresthesia in the left perioral area and hand was found to have a small hematoma just lateral to the right internal capsule. Case 2: A 67-year-old man noticed hypesthesia around the left mouth angle and thumb and index finger. Magnetic resonance imaging revealed a lesion in the right corona radiata. Case 3: A 45-year-old hypertensive man developed numbness in his perioral region and left hand that later spread to his shoulder. Magnetic resonance imaging revealed a recent small infarct in the lower lateral aspect of the right corona radiata. CONCLUSIONS: A small lesion in the corona radiata can cause cheiro-oral syndrome, whose pathogenetic mechanism in such patients may be explained by the somatotopical location or by the differing vulnerability of the neuropils in the corona radiata.

Aged↗
PubMed1992

Critical degree of renal arterial stenosis that causes hypertension in dogs.

The minimum degree of renal arterial stenosis needed to cause hypertension was identified by renal arterial angiography of anesthetized dogs. The effects of renal nerves and prostanoids on the critical stenosis were also examined. The left renal artery was constricted concentrically by a radiolucent constrictor device, and the stenosis of the artery was evaluated by cineangiography with the kidney either innervated or denervated. At this time, renal blood flow, renal perfusion pressure, and systemic blood pressure were serially monitored. In another group of dogs, renal venous and aortic blood samples were taken as the stenosis increased; these were assayed for prostaglandin E2 and plasma renin activity. The same experiments were done again after treatment with a cyclooxygenase inhibitor, aspirin DL-lysine (54 mg/kg). With the kidney either innervated or denervated, systemic blood pressure began to increase when the stenosis was more than 70% of the diameter of the renal artery; the renal blood flow decreased when the stenosis was more than 75% of the diameter. Aspirin treatment attenuated the increase in blood pressure but did not affect the autoregulation of the renal blood flow when stenosis was 70% or less. Prostaglandin E2 production increased in the stenotic kidney when the stenosis was more than 70%; aspirin inhibited prostaglandin synthesis and suppressed the stimulation of renin release. These results suggest that whether there is innervation or not, the critical degree of renal arterial stenosis that causes hypertension is more than about 70% of the diameter in the presence of renal prostaglandins; in their absence, the critical point above which hypertension occurs is 75% or more.

Animals↗
PubMed1992

'Spectacular shrinking deficit': rapid recovery from a major hemispheric syndrome by migration of an embolus.

We studied the clinical features of a major hemispheric stroke syndrome with rapid recovery ("spectacular shrinking deficit" [SSD]) compared with stroke patients with the same major initial manifestations but without rapid recovery (non-SSD). There were 118 patients with an initial major hemispheric syndrome; 14 patients (12%) had SSD. All but one SSD patient met criteria for cardiogenic brain embolism. Angiographic examination within 24 hours after stroke onset demonstrated that the occlusion sites in SSD differed from those in non-SSD and suggested that rapid embolus migration had occurred in all SSD patients but in only five of 39 non-SSD. Infarcts in SSD were smaller and often scattered over the cortices and deeper structures. Hemorrhagic transformation was less frequent in SSD. In patients with a potential cardiac source of emboli, SSD was more likely to occur in nondiabetic men less than 60 years of age.

Aged↗
PubMed1992

Changes in coagulation factors by passage through a dextran sulfate cellulose column during low-density lipoprotein apheresis.

To determine the extent of adsorption of coagulation factors by a dextran sulfate cellulose column used for selective removal of low-density lipoprotein (LDL), various coagulation factors were measured before and after application to the column during LDL apheresis. The column almost completely adsorbed many coagulation factors. Although the bradykinin concentration was markedly increased by passing the plasma through the column, this increment was suppressed by nafamostat mesilate which inhibits the initial contact phase of the intrinsic coagulation pathway. The von Willebrand factor, which forms a complex with factor VIII in plasma, is reduced in apheresis with nafamostat mesilate to the same extent as in apheresis without nafamostat mesilate. Thus, coagulation factors seem to be adsorbed by different mechanisms which include activation of the initial contact phase by the negative charges of dextran sulfate and concomitant adsorption with the phospholipid portion of lipoproteins containing apolipoprotein B or with von Willebrand factor.

Adolescent↗