Biomedical subjects

Naoto Fujiwara

Publications and source records attributed to Naoto Fujiwara.

4 recordsLinked to original sources

PubMed2005

Nocturnal blood pressure decrease is associated with increased regional cerebral blood flow in patients with a history of ischemic stroke.

BACKGROUND: It remains controversial whether there is a J-shaped relationship between blood pressure and recurrent stroke among patients with a recent history of ischemic stroke. OBJECTIVE: To investigate the relationship between regional cerebral blood flow (rCBF) and the dipping of nocturnal blood pressure in patients receiving antihypertensive treatment after ischemic stroke. METHODS AND RESULTS: Forty-seven patients with a previous history of ischemic stroke and 37 patients with a history of non-ischemic stroke underwent 24-h ambulatory blood pressure monitoring and rCBF measurement with single photon emission computed tomography. Of the 47 patients with ischemic stroke, 30 were diagnosed as having suffered atheromatous or embolic stroke, and 37 had an ischemic lesion in the territory of the carotid artery. Systolic and diastolic blood pressures during daytime and night-time were controlled at less than 140/90 mmHg by a low-salt diet or long-acting antihypertensive agents, or both. In patients with ischemic stroke, there were significant negative correlations between the percentage change in nocturnal blood pressure and rCBFs in the thalamus (r = -0.33, P = 0.02), putamen (r = -0.34, P = 0.02) and cerebral cortex (r = -0.31, P = 0.03). Multivariate analysis revealed that only the percentage change in nocturnal blood pressure was related to rCBF. There was a significant positive correlation between rCBFs in the thalamus and the cerebral cortex (r = 0.74, P < 0.05). In patients with non-ischemic stroke, there was no significant correlation between the percentage change in nocturnal blood pressure and rCBFs. CONCLUSIONS: These findings indicate that the decrease in nocturnal blood pressure is associated with the increase in rCBF in patients with a history of ischemic stroke in the territory of the carotid artery.

Adult↗

PubMed2003

Circulating coupling factor 6 in human hypertension: role of reactive oxygen species.

OBJECTIVE: Coupling factor 6 is an endogenous inhibitor of prostacyclin synthesis and might function as an endogenous vasoconstrictor in the fashion of a circulating hormone in rats. We investigated the role of coupling factor 6 in human hypertension. METHODS AND RESULTS: The patients with essential hypertension (EH) (n = 30) received a series of normal salt diet (12 g salt/day) for 3 days, low salt diet (2 g salt/day) for 7 days, and high salt diet (20-23 g salt/day) for 7 days. Normotensive control subjects (n = 27) received normal and low salt diets. The plasma level of coupling factor 6, measured by radioimmunoassay, during normal salt diet was higher in patients with EH than in normotensive subjects (17.6 +/- 1.7 versus 12.8 +/- 0.5 ng/ml, P < 0.01). Whereas the plasma level of coupling factor 6 was unchanged after salt restriction in normotensive subjects, it was decreased after salt restriction (from 12 g/day to 2 g/day) and was increased after salt loading (from 2 g/day to 20-23 g/day) in patients with EH. This increase in plasma level of coupling factor 6 was abolished by oral administration of ascorbic acid, but the level of blood pressure was unaffected. The percentage changes in plasma coupling factor 6 level after salt restriction and loading were positively correlated with those in mean blood pressure (r = 0.57, P < 0.01), and negatively correlated with those in plasma nitric oxide level (r = -0.51, P < 0.05). CONCLUSION: These indicate that circulating coupling factor 6 is elevated in human hypertension and modulated by salt intake presumably via reactive oxygen species.

Antioxidants↗

PubMed2002

Effect of losartan on nocturnal blood pressure in patients with stroke: comparison with angiotensin converting enzyme inhibitor.

BACKGROUND: Treatment of nocturnal hypertension has been reported to be beneficial for primary and secondary prevention of stroke. We compared the effects of angiotensin II antagonist (losartan) and angiotensin converting enzyme inhibitor (quinapril) on nocturnal blood pressure (BP) and sympathetic nervous activity in patients with hypertension and stroke. METHODS: According to a prospective, randomized, cross-over design, 30 hypertensive patients with a previous history of stroke (25 hemorrhage, 5 infarction) were assigned randomly to receive losartan (50 mg) or quinapril (10 mg) once daily for 4 weeks. The patients were switched to the alternative regimen for an additional 4-week period. In the last week of each treatment, 24-h ambulatory BP monitoring was performed every 30 min, and 24-h urine was collected for the measurement of catecholamine. RESULTS: Neither systolic nor diastolic BP during daytime differed between losartan and quinapril treatments, but those during nighttime were lower with losartan treatment than with quinapril treatment. The nocturnal decreases in systolic and diastolic BP were both greater with losartan treatment than with quinapril treatment (systolic BP: 6.1% +/- 5.9% v 2.5% +/- 6.9%, diastolic BP: 6.4% +/- 6.5% v 3.3% +/- 7.8%, both P <.05). The nocturnal decrease in urinary norepinephrine excretion was greater with losartan treatment than with quinapril treatment (52.8% +/- 9.7% v 42.8% +/- 17.2%, P <.05). CONCLUSIONS: Losartan enhances the nocturnal decrease in ambulatory BP compared with that of quinapril in patients with a previous history of stroke presumably by way of the suppression of nocturnal sympathetic nervous activity.

Adult↗

PubMed2002

Relationship between salt intake, nitric oxide and asymmetric dimethylarginine and its relevance to patients with end-stage renal disease.

Patients with essential hypertension (n = 24) were administered a low-salt diet (2 g NaCl/day), a high-salt diet (20-23 g) and then a low-salt diet for 7 days, and plasma levels of nitrate and nitrite (NOx) and asymmetric dimethylarginine (ADMA) were examined. There was a negative correlation between the percent changes in mean blood pressure and the plasma NOx concentration after salt loading and restriction. The percent change in plasma ADMA concentration was negatively correlated with that in the plasma NOx concentration after salt loading and restriction. In patients with end-stage renal disease (n = 51), the plasma ADMA concentration was positively correlated with the duration of dialysis treatment. The frequency of cardiovascular events was greater in patients with a plasma ADMA level of >/=3 microM than in those with a plasma AMDA level of <3 microM. The results indicate that ADMA is not only a modulator of salt sensitivity in hypertension but also a cardiovascular risk factor in end-stage renal disease.

Arginine↗