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Biomedical subjects

T Omae

Publications and source records attributed to T Omae.

At least 163 records · Page 9Linked to original sources

Prognosis and outcome of elderly hypertensives in a Japanese community: results from a long-term prospective study.

A long-term prognosis and outcome study of elderly hypertensives (aged 60 years or over) was made based on the 20-year prospective population survey conducted in a Japanese rural community (Hisayama) and the results were compared with those for younger subjects (aged 40-59 years). The risk of cardiovascular mortality related to blood pressure level increased with the elevation of either systolic or diastolic pressure in both younger and elderly groups. Cardiovascular mortality increased markedly at a systolic pressure of greater than or equal to 160 mmHg, or a diastolic pressure of greater than or equal to 100 mmHg for those aged 40-59 years. There was no cut-off level for increased risk of cardiovascular mortality for either systolic or diastolic pressures for those aged 60 years or over. Stroke mortality was seven times higher in systolic, and 10 times higher in diastolic hypertensives than in normotensives (P less than 0.01) for the group aged 40-59 years. However, deaths due to stroke and heart disease were more frequently associated with borderline (relative risk 2.3 and 2.3, respectively; P less than 0.01), systolic (relative risk 3.2 and 3.7, respectively; P less than 0.01) and diastolic hypertension (relative risk 2.1 and 4.8, respectively; P less than 0.01), compared to normotension for those aged 60 years or over. Intracerebral hemorrhage and cerebral infarction occurred more frequently in diastolic hypertensives for both young (relative risk 9.8 and 4.8, respectively; P less than 0.01) and elderly subjects (relative risk 3.4 and 1.5, respectively; P less than 0.01) than in normotensives.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Renal actions of atrial natriuretic peptide on the postischemic kidney.

The objective of this study was to evaluate the renal actions of atrial natriuretic peptide (ANP) in the unilateral postischemic kidney of anesthetized dogs with a severe reduction in glomerular filtration rate. The dose of atrial natriuretic peptide (50 ng.kg-1.min-1) we gave did not alter the mean systemic arterial pressure, renal blood flow, and glomerular filtration rate in the normal kidney, as determined in foregoing studies. ANP was infused into the intrarenal artery continuously for 60 min after the release from 45 min of complete renal artery occlusion. In the vehicle-infused group, the glomerular filtration rate fell dramatically (6% of control), the renal blood flow decreased (60% of control), and the mean systemic arterial pressure tended to increase (136% of control). The urine flow rate and urinary excretion of sodium decreased significantly (25 and 25%, respectively) at 30 min after reflow in the postischemic period. Continuous renal artery infusion of ANP resulted in a marked increase in urine flow rate (246% of control) and the urinary excretion of sodium (286% of control). The administration of ANP led to an improvement in renal blood flow (99% of control) and glomerular filtration rate (40% of control), and attenuated the rise in mean systemic arterial pressure (109% of control), compared with findings in the vehicle-infused group. Plasma renin activity and prostaglandin E2 concentration in the renal venous blood were elevated after the release from complete renal artery occlusion in both groups. These results indicate that the vascular effects of ANP on the postischemic kidney were enhanced and that the peptide maintained the natriuretic effect.

Animals↗

Intracerebral hemorrhage in a Japanese community, Hisayama: incidence, changing pattern during long-term follow-up, and related factors.

The incidence of intracerebral hemorrhage over 13 years is compared between two Hisayama cohorts. Among men aged 40 years or older, the annual incidence declined significantly from 3.1/1,000 in the early cohort (1961-1970) to 1.2/1,000 in the recent cohort (1974-1983). Massive ganglionic hemorrhage decreased, while small or medium-sized intracerebral hemorrhage increased in the recent cohort on pathologic or computed tomographic examination. These trends could be due to the reduced prevalence of hypertension in the Hisayama population. The association of serum total cholesterol with intracerebral hemorrhage is discussed based on the results during a 22-year follow-up period.

Adult↗

Autopsy study of incidence and distribution of cerebral amyloid angiopathy in Hisayama, Japan.

The incidence of cerebral amyloid angiopathy in a general population was evaluated in brains of 400 consecutive autopsies of residents of Hisayama, Japan (November 1971-October 1983). Six samples taken from frontal lobe, parietal lobe, temporal lobe, occipital lobe, hippocampus, and basal ganglia of the same side of each brain were stained with both hematoxylin and eosin and Congo red. The specimens were surveyed microscopically with polarized light for deposition of amyloid in the vascular wall. In 26 cases with brain hemorrhage, the region surrounding the hemorrhagic sites was further examined to study the probable causal relation between cerebral amyloid angiopathy and brain hemorrhage. Cerebral amyloid angiopathy was found in 40 of 218 men (18.3%) and 51 of 182 women (28.0%). The incidence increased with age in both sexes. The frontal lobe was most frequently affected (66 cases), followed by parietal lobe (65), occipital lobe (49), temporal lobe (44), and hippocampus (32); the putamen was never affected. The incidence of cerebral amyloid angiopathy did not correlate with blood pressure or with the severity of cerebral atherosclerosis. Among the 26 cases in which there was brain hemorrhage, only one cerebellar hemorrhage, in an 85-year-old man, was attributed to cerebral amyloid angiopathy. This case showed four microaneurysms in vessels, with cerebral amyloid angiopathy surrounding the hemorrhagic site. Thirty similar lesions were observed in eight cases without brain hemorrhage. Cerebral amyloid angiopathy may play an etiologic role in the development of brain hemorrhage through formation of angionecrosis and microaneurysm.

Adult↗

Treatment of acute cerebral infarction with a choline precursor in a multicenter double-blind placebo-controlled study.

A multicenter double-blind placebo-controlled study of cytidine 5'-diphosphocholine (CDP-choline) was conducted to evaluate possible clinical benefits of the drug in patients with acute, moderate to severe cerebral infarction. The patients included also suffered from moderate to mild disturbances of consciousness, and all were admitted within 14 days of the ictus. Patients were allocated randomly to treatment with either CDP-choline (1,000 mg/day i.v. once daily for 14 days) or with placebo (physiological saline). One hundred thirty-three patients received CDP-choline treatment, and 139 received placebo. The group treated with CDP-choline showed significant improvements in level of consciousness compared with the placebo-treated group, and CDP-choline was an entirely safe treatment.

Acute Disease↗

Comparative double-blind study of ketanserin versus propranolol in the treatment of essential hypertension.

To clarify the antihypertensive effect, safety and clinical usefulness of ketanserin, a comparative double-blind study was carried out in 277 patients with essential hypertension using propranolol as a control drug. Ketanserin 10 to 30 mg twice daily and propranolol 20 to 40 mg 3 times daily were administered for 12 weeks. The results showed no difference in antihypertensive effect and clinical usefulness between the drugs. In the ketanserine group, plasma concentration of total cholesterol was decreased significantly, and the reduction in heart rate was less than in the propranolol group. These findings suggest that ketanserin may satisfactorily control blood pressure.

Adult↗

Increases in renal angiotensin II content and tubular angiotensin II receptors in prehypertensive spontaneously hypertensive rats.

To examine the role of the intrarenal renin-angiotensin system in the development of hypertension in spontaneously hypertensive rats (SHR), we measured angiotensin II contents and tubular 125I-angiotensin II binding sites in the kidney of SHR and age-matched Wistar-Kyoto rats (WKY). In prehypertensive (4-week-old) SHR, not only the kidney angiotensin II content but also the angiotensin II receptor density in brush border membranes were significantly higher than in the WKY. In contrast, angiotensin II levels in the 20-week-old SHR kidneys were significantly lower than in the WKY. Acceleration of the intrarenal renin-angiotensin system and the increased density of tubular angiotensin II receptors in young SHR may therefore play an important role in the development of high blood pressure in SHR.

Angiotensin II↗

Quantitative estimation of dietary intake in patients on hemodialysis.

A simple method to calculate the amount of dietary (protein, sodium and potassium) intake in hemodialyzed patients was developed. In 8 nutritionally stable patients, the amount of dietary intake was monitored conventionally by a dietary record method. In contrast, assuming that the amount of dietary intake was equal to the amount of accumulation in the body, the former was calculated as the change in the product of serum concentrations and total body fluid volume, which was estimated based on the sex and body build of each patient. The urea accumulation was converted to the protein intake. The interdialytic dietary protein and sodium intake calculated by this method, 120 +/- 10 g and 240 +/- 40 mEq, respectively, was not significantly different from that obtained by the dietary record, while the interdialytic potassium accumulation, 60 +/- 7 mEq, was significantly smaller than the dietary intake, 110 +/- 9 mEq, obtained by the record method, though the correlation was significant. Thus, the amount of protein and sodium intake can be calculated simply without diet research or body fluid volume measurements. Although potassium intake can not be calculated exactly because of intestinal loss, this simple method gives us a rough estimate. In addition, multiple regression analysis showed that the amount of energy intake obtained by the record method may be explained by the protein and sodium intake estimated by simple calculation.

Blood Urea Nitrogen↗

Effect of ramipril, a new angiotensin converting enzyme inhibitor, on diurnal variations of blood pressure in essential hypertension.

The effect of ramipril on diurnal variations of blood pressure was studied in patients with mild to moderate essential hypertension in groups given once- (n = 18) and twice-daily (n = 21) administration with daily dosages ranging from 2.5 to 10 mg. After ramipril treatment, the blood pressure of patients in both groups was significantly reduced, and no significant differences in diurnal variation of blood pressure were observed between the 2 groups. The pulse rate did not change after administration of ramipril and no serious side effects were observed. In consideration of patient compliance, once-daily administration of ramipril seems to be optimal for the treatment of essential hypertension.

Adult↗

Efficacy and safety of ramipril (HOE 498) in the treatment of hypertension: dose finding study.

An open-label, prospective multicenter trial of ramipril was performed. The agent was administered once daily at an initial dosage of 1.25 mg and this was increased, when necessary, up to 10 mg with intervals of 2 weeks for 8 weeks. Effectiveness in 46 patients with mild to moderate essential hypertension was 28.1% at a dosage of 1.25 mg, 52.2% at 2.5 mg, 69.6% at 5 mg and 78.3% at 10 mg of ramipril alone. In 27 patients receiving baseline therapy with a thiazide diuretic, a subsequent administration of ramipril showed effectiveness in 11.1% for 1.25 mg, 48.1% for 2.5 mg and 70.4% for 5 mg. Adverse effects occurred in 11.7% of patients overall and were not serious. One patient was withdrawn because of severe headache; the other patients tolerated the treatment well. A dosage of 2.5 to 10 mg of ramipril will probably be appropriate for further evaluation of the effectiveness of this agent in a double-blind study.

Adult↗

Thyroid disorders in the general population of Hisayama Japan, with special reference to prevalence and sex differences.

Serum triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) and thyroid autoantibodies (TAA) to either microsome or thyroglobulin were measured in 1251 samples from the general population, 546 males and 705 females, aged 40 or over in Hisayama, a Japanese rural town. TAA was positive in 7.7% of men and 15.0% of women, and the male/female ratio was 1:2. This ratio was markedly different from those in hospital patients with thyroid disorders where ratios such as 1:8 for chronic thyroiditis and 1:4 for Graves' disease were found. Among the study subjects, definite hyperthyroidism was found in 0.2%, borderline hyperthyroidism in 0.7%, overt hypothyroidism in 0.3%, latent hypothyroidism in 4.2%, and non-thyroid illness in 2.4%. Overt thyroid dysfunction was more evident in women, while latent thyroid dysfunction or non-thyroidal illness was equally prevalent in men and women. These results indicate that the incidence of immunologically or functionally latent thyroid disorders is rather higher than expected, in both women and men. Some unknown factor(s) might act as a trigger to manifest thyroid dysfunction, mainly in females.

Autoantibodies↗

Severe disability related to cerebral stroke: incidence and risk factors observed in a Japanese community, Hisayama.

To elucidate the incidence of severe disability due to cerebral stroke and its related factors, prospective data of 1,621 Hisayama residents aged 40 and over were examined. Severe disability resulting from stroke was defined as patients who were unable to dress, take care of their toilet needs, and feed themselves without assistance, or who required a wheel chair for ambulation three months after the most recent episode. During 20 years of follow-up 255 stroke patients were observed among the sample population. The annual incidence of stroke per thousand was 9.8, and rate of severe disability was 2.8 for men and 6.4 and 2.0 for women, respectively. Of the 74 cases with severe disability, approximately 92% were attributed to cerebral infarction. Related factors to severe disability due to cerebral infarction were recurrent attacks, hypertension, changes in ocular fundi and diabetes mellitus among predispositions and quadriplegia or muscular contraction, and intelligent or mental disorders among inhibiting factors for functional recovery. Furthermore, in 59 autopsy cases with multiple cerebral infarctions, the frequency of disability increased as the number of infarcts increased. Hypertension and diabetes mellitus, as risk factors for cerebral infarction and factors inhibiting post-ictal functional recovery were discussed.

Adult↗

Plasma concentrations of immunoreactive-atrial natriuretic polypeptide in patients on hemodialysis.

Plasma concentrations of immunoreactive (IR)-atrial natriuretic polypeptide (ANP) were measured before and after hemodialysis (HD) as well as isolated ultrafiltration (UF) in 9 patients with end-stage renal disease. There were significant falls in plasma concentrations of IR-ANP during both UF (from 78.6 +/- 109.7 to 45.4 +/- 56.8 pg/ml; mean +/- SD; p less than 0.025) and HDs (from 84.7 +/- 48.6 to 35.0 +/- 28.4 (p less than 0.01) on first HD; from 73.7 +/- 74.2 to 31.8 +/- 21.8 pg/ml (p less than 0.01) on later HD). There were distinct positive correlations between blood pressures and plasma concentrations of IR-ANP. These results support the view that ANP is secreted mainly by the expansion of blood volume. The fall in plasma concentrations of IR-ANP after HD seems to be caused by the decrease of blood volume, but not by removal due to dialysis of the peptide. However, the physiological role of ANP in patients with end-stage renal disease remains unknown.

Atrial Natriuretic Factor↗

Regulation of plasma atrial natriuretic peptide and the cardiopulmonary baroreflex in the rat.

To study the physiological regulation of atrial natriuretic peptide (ANP), we examined the effects of volume expansion and depletion and the influence of cardiopulmonary baroreflex on plasma ANP levels in pentobarbital-anesthetized male Wistar rats. The volume expansion by acute intravenous saline infusion (2% of body weight) increased central venous pressure (CVP) and decreased heart rate (HR) in rats with intact baroreflex. The plasma ANP level in the volume expanded group was significantly higher than that in the control rats (453 +/- 100 vs 170 +/- 40 pg/ml, p less than 0.01). Conversely the plasma ANP level decreased from 214 +/- 15 to 125 +/- 13 pg/ml (p less than 0.01) accompanied by a fall in CVP and an increase in HR after nonhypotensive hemorrhage (0.8% of body weight). Hypotensive hemorrhage (2% of body weight) caused a progressive decrease in CVP while plasma ANP did not decrease further (141 +/- 25 pg/ml). Bilateral vagotomy did not modify either the basal plasma ANP level or the plasma ANP responses to volume expansion and depletion, though it inhibited HR response. These results indicate that in the rat, plasma ANP responds not only to volume expansion but also to moderate volume depletion suggesting that ANP may have a physiological role in body fluid homeostasis. The ANP response to changes in blood volume appears to be independent of the cardiopulmonary baroreflex with vagal afferent.

Animals↗