Yuji Sato

Bio: Yuji Sato is an academic researcher from University of Tsukuba. The author has contributed to research in topics: Blood pressure & Plasma renin activity. The author has an hindex of 9, co-authored 17 publications receiving 325 citations.

Role of sympathetic nervous system in hypotensive action of taurine in DOCA-salt rats.

Abstract: We tested the hypothesis that the antihypertensive effects of dietary taurine supplementation in deoxycorticosterone acetate (DOCA)-salt rats may be attributed to the suppression of sympathetic nervous system activity. In uninephrectomized rats treated with DOCA while receiving 1% NaCl solution for 2 weeks, systolic blood pressure was significantly increased as compared with that in control rats treated with vehicle suspension and tap water. Sympathetic nervous system activity was assessed by tissue norepinephrine turnover, which was determined from the rate of decline of tissue norepinephrine concentration after the administration of alpha-methyl-p-tyrosine, a potent inhibitor of the rate-limiting step of catecholamine synthesis. Cardiac and splenic norepinephrine turnover during either normal conditions or cold exposure (4 degrees C, 8 hours) were markedly increased in DOCA-salt rats as compared with control rats. Also, DOCA-salt rats had increased depressor response to hexamethonium bromide, a ganglion blocker. In contrast, supplementation of 1% taurine in DOCA-salt rats attenuated the development of the hypertension associated with the normalization of both the increased depressor response to ganglionic blockade and the accelerated cardiac and splenic norepinephrine turnover during either normal conditions or cold exposure. Taurine supplementation in control rats, however, had no effect on blood pressure or norepinephrine turnover during cold exposure. These results suggest that taurine supplementation suppresses sympathetic overactivity in DOCA-salt rats, thus leading to inhibition of the development of hypertension.

Salt sensitivity in hypertensive rats with angiotensin II administration.

Abstract: We examined the salt sensitivity of blood pressure in angiotensin II (ANG II)-induced hypertension. Wistar rats, salt loaded (0.66, 2, or 8% salt-containing diet) for 4 or 12 days, were infused intravenously with 15 or 60 ng/min of ANG II. Systolic blood pressure (SBP) was not increased by long-term (12 days) salt loading, and SBP was unchanged with ANG II and normal-salt (0.66%) diet. However, when combined with salt loading, ANG II produced hypertension in a dose-dependent fashion; compared with control (120 +/- 2 mmHg), SBP was increased with 15 ng/min of ANG II and 8% salt diet (145 +/- 5 mmHg, P less than 0.05) and with 60 ng/min of ANG II and either 2 or 8% salt diet (149 +/- 8 and 174 +/- 8 mmHg, P less than 0.05, respectively). Na space (exchangeable Na) was increased in a roughly similar pattern and correlated significantly (r = 0.531, P less than 0.05) with SBP. However, with 15 ng/min of ANG II, Na space was not different among rats on either level of salt loading, although the 8% salt diet elevated SBP. Data obtained with short-term (4 days) treatment indicate that an elevated Na space preceded development of hypertension. With 15 ng/min of ANG II and 8% salt diet for 4 days, Na space was markedly (P less than 0.05) increased, but SBP was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence, incidence, prognosis, and predisposing conditions for atrial fibrillation : population-based estimates

Abstract: Atrial fibrillation (AF) is the most common of the serious cardiac rhythm disturbances and is responsible for substantial morbidity and mortality in the general population. Its prevalence doubles with each advancing decade of age, from 0.5% at age 50-59 years to almost 9% at age 80-89 years. It is also becoming more prevalent, increasing in men aged 65-84 years from 3.2% in 1968-1970 to 9.1% in 1987-1989. This statistically significant increase in men was not explained by an increase in age, valve disease, or myocardial infarctions in the cohort. The incidence of new onset of AF also doubled with each decade of age, independent of the increasing prevalence of known predisposing conditions. Based on 38-year follow-up data from the Framingham Study, men had a 1.5-fold greater risk of developing AF than women after adjustment for age and predisposing conditions. Of the cardiovascular risk factors, only hypertension and diabetes were significant independent predictors of AF, adjusting for age and other predisposing conditions. Cigarette smoking was a significant risk factor in women adjusting only for age (OR = 1.4), but was just short of significance on adjustment for other risk factors. Neither obesity nor alcohol intake was associated with AF incidence in either sex. For men and women, respectively, diabetes conferred a 1.4- and 1.6-fold risk, and hypertension a 1.5- and 1.4-fold risk, after adjusting for other associated conditions. Because of its high prevalence in the population, hypertension was responsible for more AF in the population (14%) than any other risk factor. Intrinsic overt cardiac conditions imposed a substantially higher risk. Adjusting for other relevant conditions, heart failure was associated with a 4.5- and 5.9-fold risk, and valvular heart disease a 1.8- and 3.4-fold risk for AF in men and women, respectively. Myocardial infarction significantly increased the risk factor-adjusted likelihood of AF by 40% in men only. Echocardiographic predictors of nonrheumatic AF include left atrial enlargement (39%/ increase in risk per 5-mm increment), left ventricular fractional shortening (34% per 5% decrement), and left ventricular wall thickness (28% per 4-mm increment). These echocardiographic features offer prognostic information for AF beyond the traditional clinical risk factors. Electrocardiographic left ventricular hypertrophy increased risk of AF 3-4-fold after adjusting only for age, but this risk ratio is decreased to 1.4 after adjustment for the other associated conditions. The chief hazard of AF is stroke, the risk of which is increased 4-5-fold. Because of its high prevalence in advanced age, AF assumes great importance as a risk factor for stroke and by the ninth decade becomes a dominant factor. The attributable risk for stroke associated with AF increases steeply from 1.5% at age 50-59 years to 23.5% at age 80-89 years. AF is associated with a doubling of mortality in both sexes, which is decreased to 1.5-1.9-fold after adjusting for associated cardiovascular conditions. Decreased survival associated with AF occurs across a wide range of ages.

Call to action on use and reimbursement for home blood pressure monitoring: a joint scientific statement from the American Heart Association, American Society Of Hypertension, and Preventive Cardiovascular Nurses Association.

Abstract: Home blood pressure monitoring (HBPM) overcomes many of the limitations of traditional office blood pressure (BP) measurement and is both cheaper and easier to perform than ambulatory BP monitoring. Monitors that use the oscillometric method are currently available that are accurate, reliable, easy to use, and relatively inexpensive. An increasing number of patients are using them regularly to check their BP at home, but although this has been endorsed by national and international guidelines, detailed recommendations for their use have been lacking. There is a rapidly growing literature showing that measurements taken by patients at home are often lower than readings taken in the office and closer to the average BP recorded by 24-hour ambulatory monitors, which is the BP that best predicts cardiovascular risk. Because of the larger numbers of readings that can be taken by HBPM than in the office and the elimination of the white-coat effect (the increase of BP during an office visit), home readings are more reproducible than office readings and show better correlations with measures of target organ damage. In addition, prospective studies that have used multiple home readings to express the true BP have found that home BP predicts risk better than office BP (class IIa; level of evidence A). This call-to-action article makes the following recommendations: (1) It is recommended that HBPM should become a routine component of BP measurement in the majority of patients with known or suspected hypertension; (2) Patients should be advised to purchase oscillometric monitors that measure BP on the upper arm with an appropriate cuff size and that have been shown to be accurate according to standard international protocols. They should be shown how to use them by their healthcare providers; (3) Two to 3 readings should be taken while the subject is resting in the seated position, both in the morning and at night, over a period of 1 week. A total of >or=12 readings are recommended for making clinical decisions; (4) HBPM is indicated in patients with newly diagnosed or suspected hypertension, in whom it may distinguish between white-coat and sustained hypertension. If the results are equivocal, ambulatory BP monitoring may help to establish the diagnosis; (5) In patients with prehypertension, HBPM may be useful for detecting masked hypertension; (6) HBPM is recommended for evaluating the response to any type of antihypertensive treatment and may improve adherence; (7) The target HBPM goal for treatment is <135/85 mm Hg or <130/80 mm Hg in high-risk patients; (8) HBPM is useful in the elderly, in whom both BP variability and the white-coat effect are increased; (9) HBPM is of value in patients with diabetes, in whom tight BP control is of paramount importance; (10) Other populations in whom HBPM may be beneficial include pregnant women, children, and patients with kidney disease; and (11) HBPM has the potential to improve the quality of care while reducing costs and should be reimbursed.

Autopsy findings in the acquired immune deficiency syndrome.

Abstract: The medical records, premortem biopsy specimens, and autopsy materials from 36 patients with acquired immune deficiency syndrome (AIDS) were reviewed. The majority of the patients were homosexual men. Widely metastatic Kaposi's sarcoma was seen in eight patients, while tumor was confined to the skin in an additional ten. Four patients had high-grade lymphomas. Thirty-five of the 36 patients had at least one opportunistic infection at some point in the course of their illness. Many patients had multiple infectious agents. The most consistent and striking autopsy finding was a severe depletion of lymphoid tissues. Death in the majority (83%) of the patients was attributable to opportunistic infections affecting most commonly the respiratory tract (64%) and meninges (11%). Three patients (9%) died with widely metastatic Kaposi's sarcoma and secondary hemorrhage. ( JAMA 1984;252:1152-1159)