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Yutaka Imai

Publications and source records attributed to Yutaka Imai.

At least 37 records · Page 2Linked to original sources

[Morning surge].

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Antihypertensive Agents↗

[The Ohasama study].

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Blood Pressure Monitoring, Ambulatory↗

[HOMED-BP].

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Adult↗

Prognostic significance for stroke of a morning pressor surge and a nocturnal blood pressure decline: the Ohasama study.

There is continuing controversy over whether the pattern of circadian blood pressure (BP) variation that includes a nocturnal decline in BP and a morning pressor surge has prognostic significance for stroke risk. In this study, we followed the incidence of stroke in 1430 subjects aged > or =40 years in Ohasama, Japan, for an average of 10.4 years. The association between stroke risk and the pattern of circadian BP variation was analyzed with a Cox proportional hazards model after adjustment for possible confounding factors. There was no significant association between total stroke risk and the nocturnal decline in BP (percentage decline from diurnal level) or between total stroke risk and the morning pressor surge. The cerebral infarction risk was significantly higher in subjects with a <10% nocturnal decline in BP as compared with subjects who had a > or =10% nocturnal decline in BP (P=0.04). The morning pressor surge was not associated with a risk of cerebral infarction. On the other hand, an increased risk of cerebral hemorrhage was observed in subjects with a large morning pressor surge (> or =25 mm Hg; P=0.04). Intracerebral hemorrhage was also observed more frequently in extreme dippers (those with a > or =20% nocturnal decline in BP) than dippers (those with a 10% to 19% decline; P=0.02). A disturbed nocturnal decline in BP is associated with cerebral infarction, whereas a large morning pressor surge and a large nocturnal decline in BP, which are analogous to a large diurnal increase in BP, are both associated with cerebral hemorrhage.

Aged↗

Immunocytochemical localization of adrenomedullin 2/intermedin-like immunoreactivity in human hypothalamus, heart and kidney.

Adrenomedullin 2/intermedin (AM2/IMD) is a novel member of the calcitonin/calcitonin gene-related peptide (CGRP) peptide family. AM2/IMD has a vasodilator action, and antidiuretic and antinatriuretic effects in mice. The aim of the present study is to clarify immunolocalization of AM2/IMD in human hypothalamus, heart and kidney obtained at autopsy. Immunocytochemistry showed AM2/IMD-immunoreactive cell bodies in the paraventricular and supraoptic nuclei of human hypothalamus. Both parvocellular and magnocellular cells in the paravetricular nucleus are immunostained with AM2/IMD. Immunostaining of serial sections showed co-localization of AM2/IMD-like immunoreactivity and vasopressin in the paraventricular nucleus. Myocardial cells of the heart and renal tubular cells were positively immunostained with AM2/IMD, whereas neither renal glomeruli nor vasculature in the heart and kidney were immunostained. Reverse-transcriptase polymerase chain reaction confirmed expression of AM2/IMD mRNA in the brain, pituitary, heart and kidney. The present study has shown the wide expression of AM2/IMD in human hypothalamus, heart and kidney, raising the possibility that this novel peptide may be related to the central and peripheral regulation of the circulation and water-electrolyte metabolism.

Adrenomedullin↗

[Influence of respiratory motion in body diffusion weighted imaging under free breathing (examination of a moving phantom)].

Diffusion weighted imaging (DWI) theoretically aims to detect random motion over small distances, such as Brownian motion. Therefore, breath-hold scanning has been considered the only way to acquire DWI in the body without artifacts from bulk motion. Recent reports suggest that non-breath-hold scanning is feasible. The purpose of this study was to evaluate the influence of respiratory motion on DWI using a moving phantom model. Our results showed that the difference in apparent diffusion coefficient (ADC) was less than 10% between a static phantom and a moving phantom. There was no relation between the speed and stroke of the moving phantom and the calculated ADC. The results indicate that stable motion such as calm respiration does not cause signal loss on DWI, in contrast to intra-voxel incoherent motion (IVIM). The images obtained using this method showed high resolution and signal-to-noise ratio (SNR), suitable for three-dimensional display of the lesion.

Diffusion Magnetic Resonance Imaging↗

Expression of urocortin 3/stresscopin in human adrenal glands and adrenal tumors.

Urocortin 3 (Ucn 3)/stresscopin (SCP) is a novel peptide of the corticotropin-releasing factor (CRF) family and is a specific ligand for the CRF type 2 receptor. In the present study, we studied expression of Ucn3/SCP in the normal adrenal and adrenal tumors by radioimmunoassay and reverse transcriptase-polymerase chain reaction (RT-PCR). High concentrations of immunoreactive (IR)-Ucn3 were present in the normal portions of adrenal glands (4.2+/-0.51 pmol/g wet weight, mean+/-S.E.M., n = 14), and the levels were higher than those in the brain. IR-Ucn3 was also detected in the tumor tissues of aldosterone-secreting adenomas (6.2+/-0.6 pmol/g wet weight, n = 10), cortisol-secreting adenomas (5.0+/-1.2 pmol/g wet weight, n = 4), and pheochromocytomas (1.9+/-0.4 pmol/g wet weight, n = 7). Reverse phase high performance liquid chromatography showed that IR-Ucn3 in normal portions of adrenal glands and aldosterone-secreting adenomas was eluted mainly in the positions of Ucn3 and SCP with several minor peaks eluting earlier. The RT-PCR showed expression of Ucn3 mRNA in normal portions of adrenal gland (positive ratio; 4/4), aldosterone-secreting adenomas (3/4), cortisol-secreting adenomas (1/3) and pheochromocytomas (6/7). These findings indicate that Ucn3 is produced in normal adrenal and adrenal tumors (both adrenocortical tumors and pheochromocytomas), and suggest that Ucn3 acts as an autocrine or paracrine regulator in normal adrenal and adrenal tumors.

Adenoma↗

Prognosis of "masked" hypertension and "white-coat" hypertension detected by 24-h ambulatory blood pressure monitoring 10-year follow-up from the Ohasama study.

OBJECTIVES: We sought to investigate the prognosis in subjects with "white-coat" hypertension (WCHT) and "masked" hypertension (MHT), in which blood pressure (BP) is lower in clinical measurements than during ambulatory monitoring. BACKGROUND: The prognostic significance of WCHT remains controversial, and little is known about MHT. METHODS: We obtained 24-h ambulatory BP and "casual" BP (i.e., obtained in clinical scenarios) values from 1,332 subjects (872 women, 460 men) > or =40 years old in a representative sample of the general population of a Japanese community. Survival and stroke morbidity were then followed up for a mean duration of 10 years. RESULTS: Composite risk of cardiovascular mortality and stroke morbidity examined using a Cox proportional hazards regression model for subjects with WCHT (casual BP > or =140/90 mm Hg, daytime BP <135/85 mm Hg; relative hazards [RH])1.28; 95% confidence interval [CI] 0.76 to 2.14) was no different from risk for subjects with sustained normal BP (casual BP <140/90 mm Hg, daytime BP <135/85 mm Hg). However, risk was significantly higher for subjects with MHT (casual BP <140/90 mm Hg, daytime BP > or =135/85 mm Hg; RH 2.13; 95% CI 1.38 to 3.29) or sustained hypertension (casual BP > or =140/90 mm Hg, daytime BP > or =135/85 mm Hg; RH 2.26; 95% CI 1.49 to 3.41) than for subjects with sustained normal BP. Similar findings were observed for cardiovascular mortality and stroke morbidity among subgroups by gender, use of antihypertensive medication, and risk factor level (all p for heterogeneity >0.2). CONCLUSIONS: Conventional BP measurements may not identify some individuals at high or low risk, but these people may be identifiable by the use of ambulatory BP.

Anxiety↗

White-coat hypertension as a risk factor for the development of home hypertension: the Ohasama study.

BACKGROUND: White-coat hypertension is a condition characterized by elevated blood pressure (BP) in medical settings combined with normal ambulatory-recorded BP or self-measured BP at home (home BP). However, it is unknown whether this condition represents a transient state in the development of hypertension outside medical settings. METHODS: We followed up 128 subjects with white-coat hypertension (home BP <135/85 mm Hg and office BP > or = 140/90 mm Hg) for 8 years and compared the risk of progression with home hypertension (home BP > or = 135/85 mm Hg or start of treatment with antihypertensive medication) with 649 sustained normotensive subjects (home BP <135/85 mm Hg and office BP <140/90 mm Hg) using data from population-based home BP measurement projects in Japan. RESULTS: During the 8-year follow-up period, 60 subjects (46.9%) with white-coat hypertension and 144 (22.2%) with sustained normotension progressed to home hypertension. The odds ratio of subjects with white-coat hypertension for progression to home hypertension (adjusted for possible confounding factors) was significantly higher than for subjects with sustained normotension (odds ratio, 2.86; P<.001). This association was observed independent of baseline home BP levels. CONCLUSION: The results from the present 8-year follow-up study demonstrate that white-coat hypertension is a transitional condition to hypertension outside medical settings, suggesting that white-coat hypertension may carry a poor cardiovascular prognosis.

Adult↗

Use of 2003 European Society of Hypertension-European Society of Cardiology guidelines for predicting stroke using self-measured blood pressure at home: the Ohasama study.

AIMS: To evaluate the predictive power of the risk stratification system proposed in the 2003 European Society of Hypertension-European Society of Cardiology (2003 ESH-ESC) guidelines and to compare self-measured blood pressure at home (HBP) with casual-screening blood pressure (CBP) for prediction of first stroke among a general Japanese population. METHODS AND RESULTS: HBP and CBP were measured in 1702 subjects (> or = 40 years) who had no history of stroke and who were followed for an average of 11 years. The subjects were assigned to one of five groups with differential risk stratification according to the 2003 ESH-ESC criteria: average risk, low added risk, moderate added risk, high added risk, and very high added risk. Even in the low risk group a significantly high risk for stroke was observed, and there was a linear step up of stroke risk based on HBP, as well as on CBP. On the basis of HBP classification, a higher stroke incidence was observed in the high and very high groups compared with CBP classification. CONCLUSION: The risk stratification system proposed in the 2003 ESH-ESC guidelines is valid for the prediction of stroke in this Japanese study population, and has a stronger predictive power when based on HBP than on CBP. The results indicate the usefulness of HBP for the prediction of stroke risk in individuals.

Blood Pressure↗

Determinants of the second derivative of the finger photoplethysmogram and brachial-ankle pulse-wave velocity: the Ohasama study.

BACKGROUND: We examined different characteristics of the second derivative of the finger photoplethysmogram (SDPTG) and brachial-ankle pulse wave velocity (BAPWV) for assessing arterial function in a large general population, along with the alteration of SDPTG in hypertension. METHODS: Finger SDPTG and BAPWV were measured in 848 (544 normotensive and 304 untreated hypertensive) subjects 34 to 88 years of age. For assessing SDPTG, we calculated the B:A and D:A ratios and the aging index (AGI), based on the height of the wave components. Using univariate and multivariate analyses, determinants of SDPTG indices and BAPWV as well as differences between normotensive and hypertensive subjects were evaluated. RESULTS: We found that BAPWV was independently and positively correlated with age, blood pressure (BP), heart rate (HR), and hemoglobin A1c. The D:A ratio and AGI showed a positive and the B:A ratio a negative independent correlation with age and BP. In contrast, the D:A ratio and AGI showed a negative and the B:A ratio a positive correlation with HR. The SDPTG indices, but not BAPWV, were independently associated with gender. The multivariate-adjusted D:A ratio, AGI, and BAPWV were significantly higher and the adjusted B:A ratio was lower in hypertensive than in normotensive subjects, and hypertensive subjects showed two-fold greater adjusted risks of having high D:A and low B:A ratios. The SDPTG indices and BAPWV were mildly correlated with each other in normotensive but not in untreated hypertensive subjects. CONCLUSION: Although the SDPTG depends on various factors in a manner different from BAPWV, it may be useful for detecting vascular aging accelerated by hypertension.

Adult↗

Factors affecting home-measured resting heart rate in the general population: the Ohasama study.

BACKGROUND: We recently demonstrated that a home-measured resting heart rate (HR) can predict cardiovascular disease mortality, and it is possible that the determinants of home HR are different from casual HR. Therefore, clarifying the determinants of home HR should be useful. METHODS: Home HR was obtained using a self-monitored blood pressure (BP) measuring device. The impact of factors including home-measured BP and lifestyle on home HR was examined in 1275 members of the general Japanese population aged > or =40 years. RESULTS: Multivariate linear regression analysis demonstrated that younger age (beta = -0.08, P < or = .01), current smoking (beta = 3.22, P < or = .01), female gender (beta = 2.07, P < or = .01), and sedentary lifestyle (walking for < or =1 h/day) (beta = 2.43, P < or = .01) were determinants of elevated morning home HR. No significant association was observed between home HR and home systolic BP, whereas casual HR was significantly and positively associated with casual systolic BP. The difference between casual and home HR was also significantly and positively associated with the difference between casual and home systolic BP, suggesting that positive association between BP and HR obtained in clinic settings would be a reflection of the so-called white-coat effect. CONCLUSIONS: We observed that, with the exception of BP, most determinants of home HR were consistent with the determinants observed in previous studies using casual HR. These results suggest that reduction of home HR through modification of smoking habit or sedentary lifestyle may have a potential to decrease cardiovascular risk in addition to decreasing in these modifiable risk factor per se.

Age Factors↗

Effect of angiotensin-converting enzyme inhibitor perindopril on interneurons in MPTP-treated mice.

We examined the effects of perindopril on the dopaminergic system in mice after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment. The mice received four intraperitoneal injections of MPTP at 1-h intervals. Administration of perindopril showed dose-dependent neuroprotective effects against striatal dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) depletion 3 days after MPTP treatment. Our immunohistochemical study showed that MPTP can severe damage in tyrosine hydroxylase (TH)-immunoreactive neurons after MPTP treatment. The administration of perindopril significantly attenuated MPTP-induced substantia nigra and striatal damage. The present study also showed that the immunoreactivity of parvalbumin (PV)- or neuronal nitric oxide synthase (nNOS)-positive cells in the substantia nigra was decreased 7 days after MPTP treatment, whereas no significant changes were observed in these cells of the striatum throughout the experiments. The administration of perindopril significantly attenuated MPTP-induced decrease of the PV- or nNOS-immunoreactivity in the nigral cells. In double-labeled immunostaining with anti-PV and anti-nNOS antibody, PV-immunoreactive cell bodies and fibers were not double-labeled for nNOS-immunoreactive cell bodies and fibers in both the striatum and substantia nigra after MPTP treatment. Furthermore, PV- or nNOS-immunoreactive cell bodies and fibers in both the striatum and substantia nigra were not double-labeled for TH-immunoreactive cell bodies and fibers. These results demonstrate that the ACE inhibitor perindopril has a dose-dependent protective effect against MPTP-induced striatal dopamine, DOPAC and HVA depletion in mice. The present study also demonstrates that perindopril is effective against MPTP-induced degeneration of the nigral neurons and interneurons. Furthermore, our immunohistochemical study suggests that PV-immunoreactive cells and nNOS-immunoreactive cells are different interneurons in both the striatum and substantia nigra. Thus, our results provide further evidence that the ACE inhibitor perindopril may offer a novel therapeutic strategy for Parkinson's disease (PD).

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

Characterization of patients with disc displacement without reduction unresponsive to nonsurgical treatment: a preliminary study.

PURPOSE: Arthrocentesis and arthroscopic lysis and lavage have been described as effective treatment modalities for temporomandibular joint (TMJ) disc displacement without reduction (DDw/oR). More commonly, nonsurgical intervention is offered as the desired first-line treatment; however, a certain group of DDw/oR patients receiving nonsurgical treatment may remain unresponsive, thereby prolonging suffering and treatment dissatisfaction. The purpose of this study is to characterize these nonresponders by evaluating the characteristic pretreatment findings peculiar to this group. PATIENTS AND METHODS: This retrospective study was based on the review of pretreatment clinical and magnetic resonance imaging (MRI) findings of 52 DDw/oR patients who were treated with stabilization appliance, jaw-stretching exercise, and nonsteroidal anti-inflammatory medication. On the last treatment visit, each patient was classified as either a responder (R) or nonresponder (NR) based on the satisfaction or dissatisfaction with the treatment received, respectively. Pretreatment data were then examined and analyzed by logistic regression to identify which clinical and MRI findings were specifically related to the NR group. RESULTS: Logistic regressions indicated that NR had significantly higher odds ratio for pretreatment pain-free mouth opening of less than 30 mm (odds ratio [OR] = 7.385), "stuck" disc (OR = 4.521), and unchanged disc shape during mouth opening (OR = 4.050). Multiple logistic regression analyses revealed that these factors combined gave the highest likelihood ratio of 15.90 ( P = .001), indicating a strong possibility that these factors are associated with the NR group. CONCLUSIONS: Nonresponders can be characterized by their pretreatment pain-free mouth opening (<30 mm) in combination with MRI confirmation of "stuck" disc and unchanged disc shapes during mouth opening.

Adult↗