Biomedical subjects

W Usui

Publications and source records attributed to W Usui.

6 recordsLinked to original sources

PubMed1996

The Postpartum Support Questionnaire: reliability and validity.

Support has been found to be related to perinatal health, resulting in the development of the Postpartum Support Questionnaire based on the four categories of support (informational, material, emotional and comparison) identified by House (1981) and Cronenwett (1985). Data from four studies (N = 207) provided evidence of the psychometric properties of the instrument. Internal consistency reliability was demonstrated (alpha = .90 to .94 for total instrument). Test-retest reliability ranged from .69 to .79 for total scores and .30 to .79 for for categories of support. Measures of concurrent validity with the Personal Resource Questionnaire .85 were .42 and .48 at 6 and 8 weeks postpartum. Confirmatory factor analysis using LISREL 7 supported the four categories of support, but the use of these factors separately remains to be demonstrated.

Adult↗

PubMed1995

Effects of chemical stimulation of the rostral and caudal ventrolateral medulla on cerebral and renal microcirculation in rats.

We investigated the effects of neurons in the rostral and caudal ventrolateral medulla (RVL and CVL) on cerebral and renal microcirculation in rats. Rats were anesthetized with chloralose, paralyzed with tubocurarine, and artificially ventilated. Cerebral and renal blood flows (CBF and RBF) were measured simultaneously using laser-Doppler flowmetry. Chemical stimulation of the RVL neurons by microinjection of the excitatory amino acid L-glutamate increased arterial pressure (AP), whereas that of the CVL neurons decreased AP. Stimulation of the RVL neurons also elicited a stimulus-locked increase in CBF and a decrease in RBF. The percent change in CBF and RBF was dose-dependent as stimulus intensity was increased. Cerebral and renal vascular resistance (CVR and RVR) levels were calculated from changes in CBF or RBF and changes in mean AP. The percent reduction in CVR and percent elevation in RVR were also dose-dependent. Chemical stimulation of the CVL neurons elicited a stimulus-locked decrease in CBF and an increase in RBF. The percent reduction in CBF and percent elevation in CVR were dose-dependent. The percent reduction in RVR was also dose-dependent, while the percent elevation in RBF was not significant. Blood withdrawal reduced AP by a similar degree to CVL stimulation, but did not significantly decrease CBF. The results suggest that RVL and CVL neurons integrate cerebral and systemic microcirculation.

Animals↗

PubMed1994

[Effect of calcium antagonist (benidipine) and alpha 1 blocker (urapidil) on renal hemodynamic responses to two acute environmental stresses in spontaneously hypertensive rats (SHR)].

Renal hemodynamic responses were studied in spontaneously hypertensive rats (SHR) and Wistar-Kyoto Rats (WKY) to two acute stresses: environmental stress (foot shock (FS) and air jet (AS)). The effects of calcium channel blocker (benidipine) and alpha 1 blocker (urapidil) on these responses were studied using an ultrasonic pulsed Doppler flowmeter. The increments in mean arterial pressure (MAP) and renal vascular resistance (RVR) were greater in SHR during both stresses. On the other hand, the decrease in the renal blood flow (RBF) with these stresses almost disappeared with renal denervation. These renal hemodynamic responses in SHR disappeared with alpha 1 blocker (urapidil), but not with calcium channel blocker (benidipine). The sympathetic nervous system became hyperactive in SHR under environmental stress, Which induced specific renal hemodynamic change. These results suggest that investigations on essential hypertension should focus on clarifying not only systemic hypertensive reaction, but also changes in renal hemodynamics. Furthermore, it is necessary for antihypertensive therapy to take these hemodynamic changes into consideration.

Acute Disease↗

PubMed1993

Differential regional hemodynamic changes produced by L-glutamate stimulation of the locus coeruleus.

The locus coeruleus (LC) exerts an inhibitory influence on the cardiovascular system. Microinjection of the excitatory amino acid, L-glutamate, into the LC elicits a decrease in arterial pressure as a result of a decrease in total peripheral resistance (TPR). The aim of the present study was to examine the role of the LC in the regulation of the regional hemodynamics. Employing anesthetized rats, the blood flow to the renal, mesenteric and hind-limb vascular beds was measured with an electromagnetic flowmeter. The changes in regional blood flow and vascular resistance evoked by chemical stimulation of the LC were examined separately in each region. During the depressor response elicited by LC stimulation, the hind-limb and renal vascular resistance was significantly decreased, while the mesenteric resistance was unchanged. The vasodilatation appeared to be more prominent in the hind-limb muscle than in the systemic circulation. Renal nerve denervation attenuated the decrease in renal vascular resistance elicited by LC stimulation. However, a small part of this response still remained in the denervated kidney. The present results suggest therefore that: (1) LC neurons exert differential hemodynamic effects on the hind-limb muscle, renal and mesenteric vascular beds; (2) the largest contribution to the decrease in TPR is related to vasodilatation in the hind-limb muscles; and (3) the renal vasodilation elicited by LC stimulation is not mediated solely by the renal innervation.

Animals↗

PubMed1992

Altered basal firing pattern and postactivation inhibition of locus coeruleus neurons in spontaneously hypertensive rats.

We compared the spontaneous unit activity and inhibition of impulse activity following antidromic activation (postactivation inhibition, PAI) of locus coeruleus (LC) neurons in spontaneously hypertensive rats (SHR) with those of LC neurons in Wistar-Kyoto rats (WKY). Spontaneous spikes of the LC were analyzed by interspike time histograms. The basal unit activity and variation coefficient of the interspike interval were decreased in SHR. The duration of the PAI which was yielded by antidromic activation from the dorsal noradrenergic bundle was shortened in SHR. These findings suggest that SHR LC neurons possess an altered basal firing pattern and inhibitory mechanism.

Action Potentials↗

PubMed1992

The effect of manidipine on renal hemodynamics in essential hypertensive patients: responses to acute stress.

The effects of the calcium antagonist manidipine 20 mg/day on changes in blood pressure and renal hemodynamics in response to acute stress by the mental arithmetic test (MAT) and the cold pressor test (CPT) were investigated in 14 patients with essential hypertension (median age: 50 +/- 2, WHO stage I-II). During the drug-free period, acute stress by both MAT and CPT caused an increase in the renal vascular resistance index (RVRI) [% change in RVRI, 17% for MAT (p < 0.05) and 26% for CPT (p < 0.01)] and an increase in blood pressure [% change in mean blood pressure (MBP): 17% for MAT (p < 0.001) and 16% for CPT (p < 0.001)]. CPT stress resulted in a reduction in RAFV (% change in RAFV: -12%, p < 0.05). Oral administration of manidipine resulted in hypotensive effects at rest [MBP: from 116 to 99 mmHg, p < 0.001], no change in RAFV (31.3 to 32.9 cm/sec, p = ns), and reduced RVRI (from 3.9 to 3.2 mmHg.sec/cm, p < 0.02). Manidipine inhibited the hypertensive response to acute stress by both MAT and CPT [% change in MBP: from 17% to 11% for MAT (p < 0.02) and from 16% to 11% for CPT (p < 0.01)] and also inhibited the increase in RVRI [% change in RVRI: from 17% to -1% for MAT (p < 0.05) and from 26% to 8% for CPT (p < 0.01)]. Manidipine has beneficial effects on blood pressure and renal hemodynamics at rest in patients with essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗