Hypertension research : official journal of the Japanese Society of Hypertension
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The object of this study is to evaluate the long-term effects of olmesartan on hypertension and the renin-angiotensin-aldosterone system in hypertensive patients. This study evaluated 26 hypertensive male and female outpatients, 38-69 years of age, with a systolic blood pressure > or = 160 mmHg and/or a diastolic blood pressure > or = 95 mmHg. Oral doses of 5 to 40 mg olmesartan were administered once daily. ⋯ Angiotensin II levels decreased significantly from a baseline of 20.4+/-3.2 pg/ml to a mean of 8.6+/-2.1 pg/ml and 6.8+/-1.8 pg/ml after 6 months and 1 year of treatment, respectively. The plasma aldosterone level also decreased significantly after 6 months of treatment. In hypertensive patients, the long-term administration of olmesartan, a novel AT1 receptor antagonist, decreased both blood pressure and plasma angiotensin II levels.
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The aim of this study was to examine the roles of muscle fiber composition, capillary density and muscle blood flow in insulin resistance (IR) and the effect of cilnidipine, a calcium channel blocker in fructose-fed rats (FFR). Six-week-old male Sprague-Dawley rats were fed either normal rat chow or fructose-rich chow for 6 weeks. For the last 2 weeks, the rats were treated by gavage with a vehicle (Control and FFR groups) or with cilnidipine (FFR+Cil group). ⋯ There were no intergroup differences in capillary density. Muscle blood flow in the FFR+Cil group was higher than that in the Control or FFR groups. These results suggest that muscle fiber composition is linked to IR and that cilnidipine may improve IR in FFR either by modulating muscle fiber composition or by increasing muscle blood flow.
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Accurate measurement of blood pressure (BP) is essential in the diagnosis and treatment of hypertension, but neither auscultatory nor oscillometric methods measure intra-arterial BP accurately in all circumstances. Algorithms for automatic BP-measuring devices differ from manufacturer to manufacturer, and no clear authorized algorithm criteria have yet been established. We have devised a double-cuff sphygmotonometer to measure BP on the basis of clear algorithms, and investigated the accuracy of this new method by comparing it with the photo-oscillometric method, which is the most accurate method for non-invasive measurement of intra-arterial BP. ⋯ The comparison based on procedures of AAMI-protocol was performed in 136 hypertensive patients and 54 normotensive subjects. The difference in systolic BP between the photooscillometric and double-cuff methods was -2.26+/-2.31 mmHg (89% under 5 mmHg), and the corresponding difference in diastolic BP was 1.9+/-2.50 mmHg (94% under 5 mmHg). In conclusion, we have devised a new double-cuff method which improves on the photo-oscillometric method, and although it seems to be less accurate than the photo-oscillometric method, the clarity of its algorithm makes it superior to the conventional oscillometric and auscultatory methods employing only one cuff.
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We examined the Ca2+-buffering function of the sarcoplasmic reticulum (SR) in the resting state of arteries from spontaneously hypertensive rats (SHR) at a prehypertensive stage. Differences in the effects of cyclopiazonic acid (CPA) and thapsigargin, agents that inhibit SR Ca2+-ATPase, and of ryanodine, which depletes SR Ca2+, on tension and cellular Ca2+ level were assessed in endothelium-denuded strips of femoral arteries from 4-week-old SHR and normotensive Wistar-Kyoto rats (WKY). Addition of CPA, thapsigargin or ryanodine to the resting state of the strips caused an elevation of cytosolic Ca2+ level and a contraction in both WKY and SHR. ⋯ The resting Ca2+ influx in arteries measured by a 5-min incubation with 45Ca was significantly larger in SHR than in WKY. This influx was decreased by 10 microM CPA or 10 microM ryanodine in both WKY and SHR. These results suggest that in the resting state of the femoral artery from 4-week-old SHR, the greater part of the increased Ca2+ influx via L-type Ca2+ channels is buffered by Ca2+ uptake into the SR, while some Ca2+ reaches the myofilaments, resulting in the maintenance of resting tone.
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Clinical Trial
Influence of night shift work on psychologic state and cardiovascular and neuroendocrine responses in healthy nurses.
Night shift work has often been associated with increasing degree and frequency of various psychologic complaints. The study examined whether psychologic states after night work are related to adaptive alterations of the cardiovascular and neuroendocrine systems. We studied 18 healthy nurses (age 29+/-2 years) engaged in a modified rapid shift rotation system (day work, 8:15-17:15; evening work, 16:00-22:00; night work, 21:30-8:30). ⋯ Plasma ACTH and cortisol concentrations did not correlate with any psychologic scores. We conclude that psychologic disturbances after night work were associated with altered cardiovascular and endocrine responses in healthy nurses. Some of the psychologic complaints may be attributable to lower waking blood pressure.