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Biomedical subjects

Yutaka Imai

Publications and source records attributed to Yutaka Imai.

At least 55 records · Page 3Linked to original sources
PubMed2005

Efficacy and duration of action of the four selective angiotensin II subtype 1 receptor blockers, losartan, candesartan, valsartan and telmisartan, in patients with essential hypertension determined by home blood pressure measurements.

Our objective was to compare the efficacy and duration of action of 4 angiotensin II receptor blockers (ARBs)--losartan (25-100 mg), candesartan (2-12 mg), valsartan (40-80 mg), and telmisartan (10-40 mg)-in patients with essential hypertension using self-measurement of blood pressure at home (home BP) and to examine the differential effect of the four ARBs on home pulse pressure (home PP). After a 2-week run-in period, each of the 4 ARBs was assigned to subjects who were diagnosed as having hypertension on the basis of home BP and who were over 30 years old. The subjects were asked to take the ARB once daily in the morning and to measure home BP once in the evening and in the morning. We compared the efficacy of each ARB on home BP and home PP and assessed the duration of the BP-lowering effect using the morning effect versus evening effect ratio (M/E ratio). The antihypertensive effects of telmisartan on home systolic BP (SBP) both in the evening and in the morning and on home diastolic BP (DBP) in the morning were significantly greater than those of losartan. The effect of each ARB on home BP in the morning and in the evening was expressed as a ratio (M/E ratio). The M/E ratios of SBP/DBP in patients treated with losartan, candesartan, valsartan, and telmisartan were 0.49/0.16, 0.69/1.01, 0.82/0.88, and 0.88/0.88, respectively. The home PP-lowering effect was greater for valsartan and telmisartan than for losartan and candesartan in the morning. Among the 4 ARBs, the duration of the BP-lowering effect of losartan did not persist throughout 24 hr. The effects of the other 3 ARBs, in particular telmisartan, persisted over 24 hr when they were administered once daily in the morning. In addition, the duration of the PP-lowering effect was similar to that of the BP-lowering effect. Such long-acting property of several ARBs is essential for the modern antihypertensive treatment, and home BP measurements are useful for determining the duration of action of antihypertensive drugs. Losartan, 25 mg a day, which is usually used as an initial dose in Japan, is apparently insufficient to obtain adequate antihypertensive effect and sufficient duration of action.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2005

Prevalence of masked uncontrolled and treated white-coat hypertension defined according to the average of morning and evening home blood pressure value: from the Japan Home versus Office Measurement Evaluation Study.

OBJECTIVE: To evaluate the prevalence of masked uncontrolled and treated white-coat hypertension defined according to the average of morning and evening home blood pressure values. METHODS: The study population consisted of 3303 essential hypertensive outpatients receiving antihypertensive treatment in Japan. Information on the characteristics of the patients was collected by a physician's self-administrated questionnaire. The office blood pressure value was calculated as the average of the four readings in two visits. All patients were asked to measure their blood pressure once every morning and once every evening. In the study, we included patients with at least three measurements in the morning and in the evening, respectively. The average of all home blood pressure values was taken as the home blood pressure value. RESULTS: The mean value of home systolic/diastolic blood pressure was 136.8/79.3 mmHg, and the mean value of office systolic/diastolic blood pressure was 142.8/80.6 mmHg. Of the 3303 patients, 758 (23.0%) had controlled hypertension (home <135/85 mmHg and office <140/90 mmHg), 628 (19.0%) had masked uncontrolled hypertension (home > or =135/85 mmHg and office <140/90 mmHg), 640 (19.4%) had treated white-coat hypertension (home <135/85 mmHg and office > or =140/90 mmHg), and 1277 (38.7%) had uncontrolled hypertension (home > or =135/85 mmHg and office > or =140/90 mmHg). CONCLUSIONS: Treated white-coat hypertension and masked uncontrolled hypertension were often observed in clinical settings. Physicians need to understand the prevalence of such patients to prevent inadequate diagnosis and treatment in them.

Adult↗
PubMed2005

Isolated uncontrolled hypertension at home and in the office among treated hypertensive patients from the J-HOME study.

OBJECTIVES: To evaluate the current status of blood pressure (BP) control as measured at home and in the office, as well as to clarify and compare the prevalence and characteristics of isolated uncontrolled hypertension as measured at home (home hypertension) and in the office (office hypertension). DESIGN: A cross-sectional study. SETTING: Primary care offices in Japan. PARTICIPANTS: A sample of 3400 patients with essential hypertension (mean age, 66 years; males, 45%) receiving antihypertensive treatment. RESULTS: Overall, the mean home systolic BP (SBP)/diastolic BP (DBP) was 140/82 mmHg, and the mean office SBP/DBP was 143/81 mmHg. Of the 3400 subjects, 19% had controlled hypertension (home SBP/DBP < 135/85 mmHg and office SBP/DBP < 140/90 mmHg), 23% had isolated uncontrolled home hypertension (home SBP/DBP >/= 135/85 mmHg and office SBP/DBP < 140/90 mmHg), 15% had isolated uncontrolled office hypertension (home SBP/DBP < 135/85 mmHg and office SBP/DBP < 140/90 mmHg), and 43% had uncontrolled hypertension (home SBP/DBP >/= 135/85 mmHg and office SBP/DBP >/= 140/90 mmHg). Compared to controlled hypertension, factors associated with isolated uncontrolled home hypertension included obesity, relatively higher office SBP, habitual drinking, and the use of two or more prescribed antihypertensive drugs. Compared to uncontrolled hypertension, factors associated with isolated uncontrolled office hypertension included female gender, lower body mass index, and relatively lower office SBP. CONCLUSIONS: The use of all four, three of four, or all three predictive factors might be useful for the clinician to suspect isolated uncontrolled home or office hypertension.

Aged↗
PubMed2005

[The relationships between autonomic function and heart rate in essential hypertension].

The circadian variation of blood pressure (BP) may be mediated at least in part by circadian variation of autonomic nervous system activity. In the present study power spectral analysis of hourly R-R intervals for 24 hours was done to obtain the low frequency variability (LF: 0.04 to 0.15Hz) and high frequency variability(HF: 0.15 to 0.40Hz) in 93 patients with untreated essential hypertension. LF/HF ratio and HF were considered to be an index of sympathetic nervous activity and parasympathetic nervous activity, respectively. The relationship between heart rate (HR) and systolic blood pressure (SBP), diastolic blood pressure (DBP), HF, and LF/HF was examined. Both SBP and DBP were correlated positively with HR(r = 0.28, p < 0.05 and r = 0.27, p < 0.05, respectively) in the daytime. HF was correlated negatively and significantly with HR in both daytime and nighttime (r = -0.40, p < 0.05, and r = -0.38, p < 0.05 respectively). After averaging for SBP of 24 hours, HR in the patients whose SBP was 135mmHg or more was significantly higher than that in the patients whose SBP was less than 135mmHg. These results suggest that the decreased parasympathetic nervous activity seems to be responsible for the rise in BP.

Aged↗
PubMed2005

Efficacy of combination antihypertensive therapy with low-dose indapamide: assessment by blood pressure self-monitoring at home.

We examined the effects of the addition of low-dose indapamide to antihypertensive drugs of other classes, as well as its duration of action, using blood pressure (BP) self-monitoring at home. Seventy-six patients undergoing monotherapy with a calcium channel blocker (CCB), angiotensin converting-enzyme inhibitor (ACEI), or angiotensin AT1-receptor blocker (ARB), but had an average morning home systolic BP (SBP) > or =135 mmHg or diastolic BP (DBP) > or =85 mmHg, were studied. Indapamide (1 mg) was added to their existing treatment once daily for 4 weeks. The additional hypotensive effects of indapamide were evaluated by casual and home BPs, and the results were compared among the three groups of subjects classified according to their initial drug treatment classes. The morning/evening (M/E) ratio of BP reduction was calculated to assess the duration of the effect. Overall, indapamide significantly (P < 0.001) lowered morning home BP (147 +/- 12/87 +/- 9 mmHg to 135 +/- 12/81 +/- 9 mmHg), evening home BP (138 +/- 15/79 +/- 10 mmHg to 126 +/- 12/73 +/- 9 mmHg), and casual BP (145 +/- 21/86 +/- 14 mmHg to 136 +/- 17/81 +/- 13 mmHg). All groups showed significant indapamide-induced home SBP/DBP decreases, whereas only the ACEI and ARB groups, but not the CCB group, showed a home pulse pressure (PP) reduction. Evening SBP and PP decreases were significantly greater in the ARB group than in the CCB group. The mean M/E ratio with indapamide was 0.95 for SBP and 0.85 for DBP. Low-dose indapamide used in combination can provide additional anti-hypertensive efficacy lasting for 24 h. The added effect of indapamide may be more prominent on ARBs than on CCBs.

Aged↗
PubMed2005

[Clinical significance of home blood pressure measurements for diagnosis of hypertension in the elderly].

Systolic blood pressure elevates with increase in age. The frequency of white-coat hypertension and masked hypertension also increase with increase in age. Elderly persons tend to have abnormal circadian rhythm of blood pressure. Home blood pressure measurements are very useful to determine such pathophysiological conditions. Home blood pressure is useful not only for diagnosis of hypertension but also for treatment and management of hypertension; i.e. choice and titration of antihypertensive drugs. A minimal antihypertensive effect and duration of action of antihypertensive drugs are determined by home blood pressure measurements: the latter is established by the comparison of the antihypertensive effect of the drug in the morning with that in the evening, i.e. morning-evening ratio (ME ratio).

Aged↗
PubMed2005

[Continuous speech recognition system for radiological reporting: comparison with experience of dictation].

PURPOSE: To compare rates of accuracy of recognition between experienced dictators and inexperienced ones in using an enrollment-less continuous speech recognition (CSR) system of radiological reporting, and to evaluate the usefulness of the system. MATERIALS AND METHODS: Twenty board-certified radiologists were classified into 2 groups: a group of 10 members with more than 6 years' experience of conventional dictation by transcriptionist (group A) and a group of 10 members with no experience of dictation (group B). All radiologists created fresh radiological reports on sets of images using free-style dictation in the reports. We counted errors and total words in the reports individually, and compared the rates of accuracy of word recognition in the two groups. We used a CSR system AmiVoice (Advanced Media, Inc., Tokyo, Japan). RESULTS: The average rate of accuracy of word recognition was 96.42 +/- 1.68% in group A and 95.92 +/- 1.15% in group B. There was no significant difference in accuracy rate between the two groups. CONCLUSION: The accuracy of word recognition was independent of the experience of dictation, and the enrollment-less CSR system of radiological reporting was considered convenient and useful.

Humans↗
PubMed2005

Treatment of infantile hepatoblastoma and related complications.

Hepatorblastoma is an uncommon childhood malignant tumor of hepatic origin and recent progress of treatment strategy resulted in improved prognosis of patients with hepatoblastoma. Although patients within one year of age were considered to have better prognosis than those over that age, the treatment related deaths have been reported to be the only cause of the treatment failure of the infantile hepatoblastoma. We have successfully treated 4 infants including one with spontaneous rupture and the other with recurrence. Treatment protocol was preoperative chemotherapy using cisplatin and THP-ADR, doses of which were modified according to the age, with optional radiological interventions followed by resection of the primary tumor. This report would describe their clinical courses and experienced side effects of the treatment in order to demonstrate its risk. Trans-arterial embolizations were beneficial to stop bleeding due to rupture and to reduce intraoperative blood loss. In spite of dose modifications high hematological side effects were inevitable and cisplatn-induced hearing loss persisted in one case. In conclusion, for small infants with hepatoblastoma, controlling the inevitable side effects and active but strategic surgical and radiological interventions are essential for successful treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Short- and long-term incidence of stroke in white-coat hypertension.

White-coat hypertension (WCH) has been associated with a low risk for stroke, but long-term data are scanty. We analyzed individual data from 4 prospective cohort studies from the United States, Italy, and Japan that used comparable methodology for 24-hour noninvasive ambulatory blood pressure monitoring (ABPM). Overall, 4406 subjects with essential hypertension and 1549 healthy normotensive controls who were untreated at the time of initial ABPM were followed for a median of 5.4 years up to censoring or occurrence of a first stroke. At entry, mean age of subjects was 56 years (range 18 to 97). Prevalence of WCH was 9%. During follow-up, there were 213 new cases of stroke. Stroke rate (x100 person years) was 0.35 in the normotensive group, 0.59 in the WCH group, and 0.65 in the group with ambulatory hypertension. In a multivariate analysis, the adjusted hazard ratio for stroke was 1.15 (95% confidence interval [CI], 0.61 to 2.16) in the WCH group (P=0.66) and 2.01 (95% CI, 1.31 to 3.08) in the ambulatory hypertension group (P=0.001) compared with the normotensive group. After the sixth year of follow-up, the incidence of stroke tended to increase in the WCH group, and the corresponding hazard curve crossed that of the ambulatory hypertension group by the ninth year of follow-up. In conclusion, WCH was not associated with a definitely increased risk of stroke during the total follow-up period. However, WCH might not be a benign condition for stroke in the long term.

Adult↗
PubMed2004

Ambulatory blood pressure and 10-year risk of cardiovascular and noncardiovascular mortality: the Ohasama study.

The objective of this study was to elucidate the long-term prognostic significance of ambulatory blood pressure. Ambulatory and casual blood pressure values were obtained from 1332 subjects (872 women and 460 men) aged >or=40 years from the general population of a rural Japanese community. Survival was then followed for 14 370 patient years and analyzed by a Cox hazard model adjusted for possible confounding factors. There were 72 cardiovascular deaths during the 10.8-year follow-up. The relationship between 24-hour systolic blood pressure and the cardiovascular mortality risk was U-shaped in the first 5 years, then changed to J-shaped over the rest of the 10.8-year follow-up. After censoring the first 2 years of data, the risk flattened until it again increased for the fifth quintile of 24-hour systolic blood pressure for the 10.8-year follow-up period. For 24-hour diastolic blood pressure, the J-shaped relationship remained unchanged, regardless of follow-up duration and censoring. Ambulatory systolic blood pressure values consistently showed stronger predictive power for cardiovascular mortality risk than did casual systolic blood pressure in the 10.8-year follow-up data, whereas such relationships became more marked after censoring the first 2 years. When nighttime and daytime systolic blood pressure values were simultaneously included in the same Cox model, only nighttime blood pressure significantly predicted the cardiovascular mortality risk for the 10.8-year follow-up data. We conclude that the relationship between ambulatory systolic blood pressure and cardiovascular mortality is not U-shaped or J-shaped, and that nighttime blood pressure has better prognostic value than daytime blood pressure.

Aged↗
PubMed2004

Prediction of stroke by self-measurement of blood pressure at home versus casual screening blood pressure measurement in relation to the Joint National Committee 7 classification: the Ohasama study.

BACKGROUND AND PURPOSE: To compare the predictive power of self-measured home blood pressure (HBP) and casual blood pressure (CBP) for stroke risk in relation to the Joint National Committee 7 (JNC-7) classification. METHODS: HBP and CBP measurements were taken in 1702 subjects (> or =40 years) without a history of stroke, who were followed up for an average of 11 years. Subjects were classified into 4 groups on the basis of either HBP or CBP, according to the JNC-7 criteria: group 1 (HBP <115/75 mm Hg; CBP <120/80 mm Hg); group 2 (115/75< or =HBP<135/85 mm Hg; 120/80< or =CBP<140/90 mm Hg); group 3 (135/85< or =HBP<150/95 mm Hg; 140/90< or =CBP<160/100 mm Hg); and group 4 (HBP> or =150/95 mm Hg; CBP > or =160/100 mm Hg). Groups 2, 3, and 4 were further divided into 2 subgroups (a and b): those without and with cardiovascular disease risks, respectively. The risk of the first stroke in these groups was examined by the Cox hazards model adjusted for age and sex. RESULTS: The stroke risk in groups 3b and 4b (defined by HBP and CBP) was 2 to 5x higher than that in group 1 with significant differences. The risk in groups 2a, 3a, and even 4a was not significantly different from that in group 1 by the CBP-based classification, but the risk in group 4a was significantly higher than that in group 1 by the HBP-based classification, which also showed a stepwise increase in risk from groups 2a to 4a. CONCLUSIONS: The JNC-7 classification had a stronger predictive power using HBP-based classification compared with CBP-based classification, suggesting the usefulness of HBP in the management of hypertension.

Aged↗
PubMed2004

Prognostic value of home heart rate for cardiovascular mortality in the general population: the Ohasama study.

BACKGROUND: Recently, the advantages of self-measurement of blood pressure (BP) at home have been recognized. The same advantages could also be applicable to resting heart rate (HR) values assessed at home using a device designed for home BP measurement. However, there have been no studies investigating whether home HR values predict the risk of cardiovascular disease mortality. We therefore investigated the usefulness of HR values in predicting cardiovascular mortality using a device that allowed self-measurement of BP and HR at home. METHODS: The association between the home-measured resting HR and the 10-year risk of cardiovascular mortality was examined in 1780 Japanese individuals >/=40 years of age who had no significant arrhythmias. A Cox proportional hazards model that adjusted for major risk factors was used. RESULTS: An increase of 5 beats/min in the morning home HR measurement was associated with a 17% increase in the risk of cardiovascular mortality (95% confidence interval 5% to 30%). This relationship was also statistically significant after adjustment for home BP values. Even when home-measured systolic BP was within the normal range (<135 mm Hg), subjects with HR >/=70 beats/min had a higher risk of cardiovascular mortality (relative hazard 2.16, 95% confidence interval 1.21 to 3.85) than those with normal systolic BP and HR values. CONCLUSIONS: Self-measurement of HR at home, together with self-measurement of BP, is a simple method of providing useful clinical information for assessing cardiovascular risk.

Adult↗
PubMed2004

Elevated plasma levels of immunoreactive urotensin II and its increased urinary excretion in patients with Type 2 diabetes mellitus: association with progress of diabetic nephropathy.

Urotensin II (UII) is the most potent vasoconstrictor peptide ever identified. In order to clarify the pathophysiological role of UII in diabetes mellitus, we examined plasma immunoreactive UII levels and urinary excretion of immunoreactive UII in 10 control subjects and 48 patients with Type 2 diabetes mellitus. The patients were divided into three groups according to the renal function: Group I with Ccr > or = 70 ml/min, group II with 30 < or = Ccr <70 ml/min and group III with Ccr <30 ml/min. Plasma immunoreactive UII levels were elevated in the three diabetic groups compared with normal controls (P <0.05). Group III patients had significantly higher plasma immunoreactive UII levels (15.9 +/- 2.2 fmol/ml, mean +/- S.E.M., n=6) by approximately 1.6-fold than did group I (10.9 +/- 0.9 fmol/ml, n=17) and group II (10.8 +/- 0.8 fmol/ml, n=25) (P <0.05). Urinary excretion of immunoreactive UII was significantly increased in group III patients (52.4 +/- 14.8 pmol/day) by more than 1.8-fold compared with control subjects, groups I and II (P <0.005). Fractional excretion of immunoreactive UII significantly increased as renal function decreased. Presence of diabetic retinopathy or neuropathy had negligible effects on plasma immunoreactive UII levels and urinary immunoreactive UII excretion. Reverse phase HPLC analyses showed three immunoreactive peaks in normal plasma extracts and multiple immunoreactive peaks in normal urine extracts. Thus, Type 2 diabetes mellitus itself is a factor to elevate plasma immunoreactive UII levels, and accompanying renal failure is another independent factor for the increased plasma immunoreactive UII levels in Type 2 diabetic patients. Increased urinary immunoreactive UII excretion in Type 2 diabetic patients with advanced diabetic nephropathy may be due not only to the elevated plasma immunoreactive UII levels but also to increased UII production and/or decreased UII degradation in the diseased kidney.

Adult↗
PubMed2004

Clear cell adenocarcinoma of the tongue.

A firm, ulcerated tumor formed on the left side of the tongue of an elderly woman. Histopathological analysis showed that this unusual neoplasm was composed of monomorphic polygonal cells that exhibited a clear cytoplasm containing large amounts of periodic acid Schiff (PAS)-positive, diastase-digestive material. Most of the tumor cells stained immunohistochemically for Cytokeratin, high-molecular, CAM5.2, and epithelial membrane antigen (EMA), but were negative for alpha-smooth muscle actin, vimentin, glial fibrillary acid protein (GFAP), and S-100 protein. These findings supported a diagnosis of clear cell adenocarcinoma. Although patients with this type of tumor generally have a favorable prognosis, the tumor in our patient was fast-growing and contained a large number of Ki-67 positive cells, which are known to be highly proliferative. Thus, this case highlights the fact that even clear cell adenocarcinomas that are usually slow-growing should be investigated by conventional morphological techniques and their proliferative activity quantified in order to select the most appropriate treatment strategy.

Adenocarcinoma, Clear Cell↗
PubMed2004

Endorectal MRI for prediction of tumor site, tumor size, and local extension of prostate cancer.

OBJECTIVES: To assess the value of endorectal magnetic resonance imaging (MRI) for detecting the tumor site, tumor size, and disease extent in patients with localized prostate cancer. METHODS: The MRI findings were compared with the histopathologic findings of radical prostatectomy specimens in 95 patients. RESULTS: The histologic examination revealed 186 cancer foci. Endorectal MRI detected 109 cancer foci. The accuracy, sensitivity, and positive predictive value of endorectal MRI for detecting tumor foci greater than 1.0 cm in diameter was 79.8%, 85.3%, and 92.6%, respectively; the corresponding value for detecting tumor foci smaller than 1.0 cm was 24.2%, 26.2%, and 75.9%, respectively. The maximal tumor diameter on endorectal MRI correlated with that shown by histologic examination for tumors larger than 1.0 cm in diameter. However, it did not correlate significantly with the histologic diameter of tumors smaller than 1.0 cm. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of endorectal MRI was 74.7%, 57.1%, 82.1%, 57.1%, and 82.1%, respectively, for the detection of extracapsular extension and was 75.8%, 62.1%, 81.8%, 60.0%, and 83.1%, respectively, for local staging. CONCLUSIONS: The results of the present study suggest that endorectal MRI is useful for predicting local extension, as well as tumor site and tumor size, of cancer foci greater than 1.0 cm in diameter.

Adenocarcinoma↗
PubMed2004

Protective effects of neuronal nitric oxide synthase inhibitor in mouse brain against MPTP neurotoxicity: an immunohistological study.

We recently reported that neuronal nitric oxide synthase (nNOS) inhibitor, 7-nitroindazole, can protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity in mice. It protected against both dopamine depletions and tyrosine hydroxylase (TH) positive neuron decreases in the mouse brain. In the present study, we further examined whether 7-nitroindazole can also protect against the alterations of TH-, microtubule-associated protein 2a,b (MAP2)-, glial fibrillary acidic protein (GFAP)-, parvalbumin (PV)-, dopamine transporter (DAT)-, nNOS- or endothelial NOS (eNOS)-positive cells, in comparison with pargyline as a relatively selective inhibitor of the monoamine oxidase-B (MAO-B). The present study showed that nNOS inhibitor as well as MAO-B inhibitor has a dose-dependent protective effect against MPTP-induced striatal dopamine and DOPAC depletion in mice. Furthermore, the present study revealed that 7-nitroindazole and pargyline can protect the alterations of immunohistochemical changes in the striatum and substantia nigra after MPTP treatment. These protective effects may be, at least in part, produced by the reduction of neuronally derived NO and peroxynitrite caused by MPTP. Our results also demonstrate that MPTP can cause functional damage of interneurons in the substantia nigra. These results suggest the possibility that nNOS inhibitors as well as MAO-B inhibitors may be therapeutically useful in neurodegenerative diseases such as Parkinson's disease. Thus our present results provide valuable information for the pathogenesis of degeneration of the nigrostriatal dopaminergic neuronal pathway.

3,4-Dihydroxyphenylacetic Acid↗