Biomedical subjects

T Ishimitsu

Publications and source records attributed to T Ishimitsu.

166 records · Page 10Linked to original sources

PubMedDate not supplied

Comparison of the effects of amlodipine and losartan on 24-hour ambulatory blood pressure in hypertensive patients.

Effects of amlodipine (AML), a long-acting calcium antagonist, and losartan (LOS), an angiotensin II receptor antagonist, on 24-hr blood pressure profile were compared in 15 patients with essential hypertension. After 4 weeks of placebo period, the patients were treated with AML or LOS in a random crossover design for 12-16 weeks each. Either drug was given once daily at 0800 and the doses were titrated so that the office blood pressure was reduced lower than 140/90mmHg. At the end of each period, 24-hr blood pressure was monitored. Average office blood pressure was lowered from 158 +/- 2/ 98 +/- 2 mmHg to 134 +/- 1/87 +/- 1 mmHg by AML and 134 +/- 2/88 +/- 1 mmHg by LOS. Average 24-hr blood pressure was also reduced from 144 +/- 3/ 92 +/- 2 mmHg to 131 +/- 2/84 +/- 2 mmHg by AML and 135 +/- 3/85 +/- 2 mmHg by LOS. The averaged 24-hr systolic blood pressure was significantly lower in AML than in LOS (p < 0.05). Then, the 24-hr blood pressure was analyzed for four segments; morning (0530-0900 h), daytime (0930-1800 h), evening (1830-2300 h) and night (2330-0500 h). Although the daytime blood pressure was comparable between AML and LOS, systolic blood pressure in the evening and morning hours were lower in AML than in LOS (133 +/- 2 vs. 138 +/- 3mmHg,p<0.01; 129 +/- 3 vs. 134 +/- 4,p<0.05). Troughtopeakratio of antihypertensive effect on systolic blood pressure was significantly greater in AML than in LOS (62 +/- 5% vs. 55 +/- 4%, p < 0.05). Either drug did not cause reflective increase in pulse rate over 24 hours. These results suggest that both AML and LOS are equally effective in lowering daytime blood pressure without eliciting reflex tachycardia, however, the antihypertensive effect of AML lasts longer than that of LOS. Such information seems important to achieve 24-hr blood pressure control using these drugs.

Adult↗

PubMedDate not supplied

Effects of amlodipine and nifedipine retard on autonomic nerve activity in hypertensive patients.

1. The effects of 1,4-dihydropyridine calcium antagonists with different biological half-lives, amlodipine and nifedipine retard on 24 h blood pressure (BP), heart rate (HR) and autonomic nerve activity in patients with essential hypertension were compared. 2. Twenty patients (six men and 14 women; mean (+/- SEM) age 63 +/- 2 years) with essential hypertension were enrolled in the present study. Their ambulatory BP and electrocardiograms were monitored for 24 h at intervals of 30 min with a portable recorder after a 4 week drug-free period, after a 4 week treatment period with amlodipine (2.5 or 5 mg once daily) and after a 4 week treatment period with nifedipine retard (10 or 20 mg twice daily). The order of the three periods was randomized. Autonomic nerve activity was evaluated by power spectral analysis of HR variability, using the high frequency (HF) component as an index of parasympathetic activity and the ratio of the low frequency (LF) to the HF component as an index of sympathovagal balance. 3. Amlodipine and nifedipine retard significantly lowered the 24 h BP to a similar extent (amlodipine: -12.7 +/- 2.6/-5.6 +/- 1.4 mmHg, P < 0.01/P < 0.01; nifedipine retard: -15.1 +/- 2.1/-6.9 +/- 1.5 mmHg, P < 0.01/P < 0.01). Amlodipine did not change the 24 h average HR, while nifedipine retard significantly increased it (+3.3 +/- 1.2 b.p.m., P < 0.05). Amlodipine also did not change the HF component or the ratio of the LF to the HF component. However, nifedipine retard significantly decreased the HF component (P < 0.01) and increased the ratio of the LF to the HF component (P < 0.05). 4. These results suggest that nifedipine retard caused a decrease in parasympathetic activity and an increase in sympathetic activity with reflex tachycardia in these patients with essential hypertension, while amlodipine did not produce such effects on the autonomic nervous system.

Amlodipine↗

PubMedDate not supplied

High potassium diets reduce macrophage adherence to the vascular wall in stroke-prone spontaneously hypertensive rats.

Our previous study demonstrated that high potassium (K) diets reduce stroke mortality in stroke-prone spontaneously hypertensive rats (SHRsp) even when the blood pressure is not lowered. On the other hand, macrophage infiltration into the vascular wall is known to play an important role in the development of arterial lesions. In this study, in vivo and in vitro experiments were performed to examine the effect of high K diets on macrophage adherence to the vascular wall in SHRsp rats. In the in vivo study, 51Cr-labelled macrophages, collected from the peritoneal cavity, were injected intravenously to SHRsp rats fed 6% high NaCl diets containing either normal 0.5% K or high 2.1% K, and, 45 min later, the rats were perfused with buffered saline to remove blood. Radioactivity from macrophages in the aorta was 40% lower in the high K SHRsp than in the normal K SHRsp (p < 0.002), and the brain of high K SHRsp also showed a 52% lower macrophage radioactivity than that of normal K SHRsp (p < 0.007). Although the mean blood pressure was slightly lower in the high K diet group than in the normal K diet group (167 vs. 184 mm Hg), these differences remained still prominent even when we compared groups with matching blood pressures; -33% for the aorta (p < 0.02) and -55% for the brain (p < 0.02). In the in vitro study, the aortas of SHRsp rats similarly fed on normal or high K diet were excised and mounted in a perfusion chamber. They were perfused with labelled macrophages at normotensive or hypertensive pressure. In normal K SHRsp, macrophage radioactivity remained in the washed aorta was 158% higher in high perfusion pressure group than in normal pressure (p < 0.002). However, they did not significantly differ between two perfusion pressures in high K SHRsp. These results indicate that high K diets reduce endothelial injuries which allow adherence and infiltration of macrophages into the vascular wall of hypertensive animals, and thereby contribute to the reduction of vascular lesions and stroke mortality.

Animals↗

PubMedDate not supplied

Computer simulation of optimum personnel assignment in hospital pharmacy using a work-sampling method.

A computer simulation of the dispensing work performed in a hospital pharmacy was undertaken, based on analysis data from a work-sampling method and utilizing a personal computer. As a result it was found to be possible to estimate the complete work volume of a day based on the number of prescriptions in the day, and hence to predict fairly precisely the number of pharmacists required to complete that work. The method also enables the users to assign the optimum number of staff for dispensing duties according to the estimated number of prescriptions and the optimum waiting time of patients. A correlation has been noted between the total residence time of prescriptions and the mean waiting time of patients. Using this simple and effective technique to efficiently assign personnel makes it possible to cope with an increasing workload and limited number of staff.

Computer Simulation↗