Biomedical subjects

Junichiro Hashimoto

Publications and source records attributed to Junichiro Hashimoto.

45 records · Page 3Linked to original sources

PubMed2004

Practical aspect of monitoring hypertension based on self-measured blood pressure at home.

Devices for home blood pressure (BP) measurement are produced worldwide at a rate of more than 10 million a year and 30 million such devices have already been distributed in Japan. The clinical significance of home BP measurement is obvious; patients can recognize the effects of antihypertensive treatment. Home BP measurements encourage medication compliance, follow-up clinic visits, and active participation in the medical treatment, thus resulting in improved management of hypertension. Home BP measurements more accurately reflect damage to target organs and the prognosis of cardiovascular diseases. The purpose of home BP measurements is to obtain information on the patient's inherent BP pattern using longterm, repetitive measurement under controlled conditions. Since home BP is measured under controlled condition, values are reproducible, and thus, useful in the diagnosis and treatment of hypertension. Blood pressures measured under standardized condition are indispensable when comparing data among individuals, among groups and among institutes. Working Group of Japanese Society of Hypertension (JSH) established JSH Guidelines for Self-Monitoring of Blood Pressure at Home in 2003. Standardization of the measurement procedure may elevate the position of home BP measurements for the purpose of diagnosing and treating hypertension. As a result, home BP measurements may improve the accuracy of screening for hypertension and assessment of BP control during treatment and encourage drug compliance. Home BP measurements, under such controlled conditions, should have a beneficial effect on the economics of diagnosing and treating hypertension.

Blood Glucose Self-Monitoring↗

PubMed2003

Therapeutic effects of evening administration of guanabenz and clonidine on morning hypertension: evaluation using home-based blood pressure measurements.

OBJECTIVE: To clarify the effects of bedtime administration of the centrally acting alpha(2)-agonists, guanabenz and clonidine, on morning hypertension. METHODS: Patients with morning hypertension were assigned to receive once-daily evening administration of guanabenz (2 mg/day, n = 81; 4 mg/day, n = 2) or clonidine (75 microg/day, n = 40; 150 microg/day, n = 10) for 4 weeks, and the blood pressure (BP)-lowering effects of these drugs in the morning and evening were evaluated by assessing self-monitored BP in the home environment. The subjects were then subdivided into different groups according to their evening BP, and the effects of guanabenz and clonidine on evening BP were evaluated further for each group. In addition, as a substitute for the trough/peak ratio, the evening/morning (E/M) ratio was calculated to assess the duration of action of the two alpha(2)-agonists. RESULTS: Evening dosing with guanabenz or clonidine lowered morning BP significantly. Both drugs decreased evening BP in the subgroup of subjects with a high evening BP, but not in those with a normal evening BP. The individual E/M ratios for guanabenz, but not for clonidine, were significantly greater in those with a high evening BP than in those with a normal evening BP. In the early treatment period, treatment with guanabenz resulted in a higher diastolic E/M ratio in those subjects with a high evening diastolic BP than did treatment with clonidine. CONCLUSION: The results suggest that evening administration of the central alpha(2)-agonists guanabenz and clonidine effectively suppresses the morning BP elevation in treated hypertensive patients.

Aged↗

PubMed2003

Heart rate measurement and outcome.

Previous studies on the predictive value of heart rate and heart rate variability for the risk of cardiovascular disease remains controversial. Since heart rate is known to be variable with several physical and mental stresses, the inconclusive nature of previous studies might reflect the difference in accuracy and reproducibility of the heart rate measurement. In the Ohasama study, which has been conducted since 1985 in the northern part of Japan, home measurements and ambulatory monitoring of heart rate as well as blood pressure were examined with special reference to cardiovascular mortality. Heart rate measured at home and averaged for 21 days was shown to be linearly associated with cardiovascular mortality, while heart rate variability (standard deviation of daytime ambulatory heart rate measured every 30 min) inversely correlated with cardiovascular mortality. In conclusion, heart rate and heart rate variability must not be overlooked when evaluating hypertension.

Blood Pressure↗

PubMed2002

Insufficient duration of action of antihypertensive drugs mediates high blood pressure in the morning in hypertensive population: the Ohasama study.

Blood pressure (BP) usually peaks in the morning. The circadian variation of the onset of cardiovascular disease mimics this circadian BP variation. To examine the determinants of the BP difference between the self-recorded BP in the morning (home BP) and daytime average ambulatory BP a cross sectional study was done in the general population of Ohasama, Japan. 1207 subjects > or = 20 years measured both home (more than 14 times) and ambulatory BPs (326 treated for hypertension and 881 untreated subjects), The prevalence of subjects with the systolic BP difference (home BP in the morning - daytime ambulatory BP) of > or = 10 mmHg (high morning BP) was 5.6% in untreated normotensives, 2.9% in untreated hypertensives, and 25.8% in treated hypertensives. This trend was also observed for diastolic pressure. Multiple regression analysis demonstrated that age, male sex, and use of antihypertensive drugs were positively associated and day-night difference of BP was negatively associated with the high morning BP, respectively. These results suggest an insufficient duration of antihypertensive action of widely used antihypertensive drugs in Japan from the 1980s to 1990s. The amplitude of the day-night difference of ambulatory BP in subjects with a high morning BP was lower (non-dipping) than that without high morning BP. The high morning BP is not necessarily accompanied by hypertension but might be mediated, at least in part, by an insufficient duration of action of antihypertensive drugs. The high morning BP accompanies so-called non-dipper pattern of circadian BP variation. An insufficient duration of action of drugs may partly mediate non-dipping in subjects with antihypertensive medication.

Adult↗

PubMed2002

Angiotensin-converting enzyme I/D polymorphism and hypertension: the Ohasama study.

OBJECTIVE: Angiotensin-converting enzyme (ACE) I/D polymorphism in intron 16 of the ACE gene was analyzed in a general Japanese population in relation to self-blood pressure (BP) measurement at home (home BP) and ambulatory BP monitoring (ABPM) to determine the association between genetic variants of this polymorphism and hypertension. DESIGN: A cross-sectional study. METHODS AND RESULTS: We genotyped the ACE I/D polymorphism in 1245 subjects with home BP and 803 subjects with ABPM in Ohasama, a rural community in Japan. All the subjects were 40 years of age and over, and gave written informed consent for the present genetic analysis. Hypertensive subjects were defined as those receiving antihypertensive drugs and those who had a home BP higher than 135 mmHg in systole and/or higher than 85 mmHg in diastole. The frequencies of the II, ID, and DD genotypes in these Japanese subjects were 0.45, 0.45, and 0.10, indicating a lower frequency of the D allele (0.33) than in Caucasians. There was no significant difference of BP level, prevalence of hypertension or nocturnal decline in BP among the genotypes. There were no differences in the prevalence of previous cardiovascular disease, age, body mass index, male gender, smoking, or biochemical and hormonal parameters among the three genotypes. CONCLUSION: The present results indicate the absence of direct effects of the ACE D-allele on BP level, prevalence of hypertension, prevalence of cardiovascular disease, and circadian BP variation. We conclude there is little association between ACE I/D polymorphism and hypertension in the general Japanese population.

Adult↗

PubMed2002

Prognostic significance of the nocturnal decline in blood pressure in individuals with and without high 24-h blood pressure: the Ohasama study.

OBJECTIVE: To examine the relationship between the normal nocturnal decline in blood pressure and the risk of cardiovascular mortality in individuals with and without high 24-h blood pressure values. METHODS: We obtained 24-h ambulatory blood pressure readings from 1542 residents of Ohasama, Japan, who were aged 40 years or more and were representative of the Japanese general population. We then followed up their survival for a mean of 9.2 years. The relationship was analysed using a Cox proportional hazards model adjusted for possible confounding factors. RESULTS: There was a linear relationship between the nocturnal decline in blood pressure and cardiovascular mortality. On average, each 5% decrease in the decline in nocturnal systolic/diastolic blood pressure was associated with an approximately 20% greater risk of cardiovascular mortality. There were no significant interactions for the risk between 24-h systolic/diastolic blood pressure values and continuous values for the nocturnal decline in blood pressure ( for interaction 0.6). Even when 24-h blood pressure values were within the normal range ( 135/80 mmHg, average 118/69 mmHg), diminished nocturnal decreases in systolic/diastolic blood pressure were associated with an increased risk of cardiovascular mortality. CONCLUSIONS: This is the first study to demonstrate that a diminished nocturnal decline in blood pressure is a risk factor for cardiovascular mortality, independent of the overall blood pressure load during a 24-h period, in the general population.

Aged↗

PubMed2002

Pulse wave velocity and the second derivative of the finger photoplethysmogram in treated hypertensive patients: their relationship and associating factors.

OBJECTIVES: To clarify the factors influencing two measures of arterial stiffness, pulse wave velocity (PWV) and the second derivative of the finger photoplethysmogram (SDPTG), and to evaluate their relationship in treated hypertensive subjects. SUBJECTS AND METHODS: The subjects were 294 hypertensive patients aged 32-91 years (mean, 61.4 +/- 10.5 years). After blood pressure (BP) was measured, carotid-femoral PWV and SDPTG were recorded with the subjects in the supine position, with the aid of an automatic device. For assessing SDPTG, we focused mainly on the ratios of the absolute value of the height of the early negative 'b' wave (B) and that of the late re-decreasing 'd' wave (D) to that of the initial positive 'a' wave (A), namely the B : A and D : A ratios, and the aging index (AGI). Factors influencing PWV and SDPTG indices, and the relationship between PWV and SDPTG indices were evaluated by bivariate and multivariate analyses. RESULTS: According to multiple linear regression analysis, age, systolic blood pressure (SBP), and heart rate (HR) were variables independently and positively correlated with PWV. The age and BP were significantly and independently related to SDPTG indices; there were positive correlations with the D : A ratio and AGI, and negative correlations with the B : A ratio. HR was correlated negatively with the D : A ratio and AGI, and positively with the B : A ratio. According to multiple logistic regression analysis, adjusted-odds ratios of high PWV, low B : A ratio, high D : A ratio, and high AGI were significantly elevated among the elderly and among the subjects with uncontrolled BP. Although PWV and the SDPTG indices were associated with common factors, including age and BP, bivariate analysis revealed that they were only weakly correlated with each other. CONCLUSIONS: The results suggest that in hypertensive patients, PWV and SDPTG provide different information about arterial properties at central and peripheral sites.

Aged↗

PubMed2002

Blood pressure control assessed by home, ambulatory and conventional blood pressure measurements in the Japanese general population: the Ohasama study.

To assess blood pressure control in the Japanese population, we analyzed previously obtained measurements of conventional, home and ambulatory blood pressures in 1,174 subjects aged > or =40 in a Japanese community. On the basis of conventional blood pressure values and the use of antihypertensive medication, participants were classified as normotensive, untreated hypertensive and treated hypertensive subjects. When 140/90, 135/85 and 135/85 mmHg were used as the hypertension criteria for conventional, home and ambulatory blood pressure measurements, respectively, all three blood pressure values were higher in untreated and treated hypertensive subjects than in normotensive subjects. Among the treated hypertensive subjects, approximately half were classified as hypertensive not only by conventional blood pressure, but also by home or ambulatory measurements. Approximately 10% of the subjects defined as normotensive by conventional blood pressure measurement were classified as hypertensive by home or ambulatory measurements, whereas 60% of the untreated hypertensive subjects as defined by conventional blood pressure measurement had normal home or ambulatory blood pressure values. Therefore, we concluded that 1) the poor blood pressure control in treated hypertensive subjects was attributable not only to the white coat effect but also to inadequate control of blood pressure; and 2) a certain percentage of subjects were misclassified as hypertensive or normotensive by conventional blood pressure measurement.

Adult↗

PubMed2002

[The autonomic nervous activity of hypertension].

Autonomic nervous function was evaluated by means of power spectral analysis of heart rate variability in hospitalized patients with different circadian blood pressure(BP) variation, i.e., dipper(n = 33), non-dipper(n = 37), extreme dipper(n = 26) and riser(n = 20). Ambulatory BP monitoring was performed by A & D TM2425 based on a cuff-oscillometric method. Circadian BP variation was defined in these subjects. The non-dipper, extreme dipper and riser subjects were defined as those whose nocturnal decrease in systolic BP was less than 10%, more than 20% and elevation of BP, as compared to the daytime BP, respectively. Power spectral analysis of hourly R-R intervals for 24 hours was done to obtain the low frequency power(LF, 0.04 to 0.15 Hz) and high frequency power(HF, 0.15 to 0.40 Hz). LF/HF ratio was considered to be an index of sympathetic nervous activity, and HF parasympathetic nervous activity, respectively. LF/HF was significantly lower in both riser and non-dipper than that in dipper subjects throughout the day. In non-dipper day-night difference of HF was smaller than in dipper and extreme dipper groups. These findings indicated that riser and non-dipper hypertensives were characterized by decreased physiological circadian fluctuation of autonomic functions when compared to dipper subjects. The circadian variation of BP may be mediated at least in part by circadian variation of autonomic nervous system activity.

Adult↗