ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Plasma and intra-erythrocytic magnesium concentrations were determined in 27 patients with pre-eclampsia and in 22 healthy pregnant women. In the pre-eclamptic women, the Mg2+concentrations were measured before and after treatment with Mg2+salts and after delivery. The plasma Mg2+concentration was not significantly different in the pre-eclamptic and the healthy pregnant women. The intra-erythrocytic Mg2+concentration before treatment with Mg2+was significantly lower in the pre-eclamptic patients than in the healthy pregnant women [1.33± 0.29 versus 1.01± 0.16mmol/l (means± s.d.);P< 0.05] and increased after treatment with Mg2+to 1.19± 0.24mmol/l. Lowered cellular Mg2+concentrations in pre-eclampsia may contribute to the development of hypertension in this disorder.

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

A 3 kilobase (kb)EcoRl fragment cloned from the genome of the spontaneously hypertensive rat (SHR) displayed restriction fragment length polymorphism (RFLP) compared with the genome of the Wistar-Kyoto rat (WKY) when total genomic Southern blot analysis was performed for two restriction enzymes,PstlandPvull. Sequencing of the DNA fragment cloned from genomic SHR and WKY libraries revealed that this 3 kbEcoRI fragment harbours three point mutations. Two of them (C to T and A to T) are situated in the middle of the restriction sites forPstlandPvull, thus disrupting the recognition sites for these enzymes in the SHR genome. Southern blot analysis using total complementary (c) DNA obtained from cDNA libraries of aortic smooth muscle cells from SHR and a whole WKY kidney, with this 3 kbEcoRI fragment as a probe, showed polymorphic bands suggesting that these point mutations are reflected in the sequences of messenger (m) RNA transcribed from the gene encoded in this 3 kb fragment. Detection of two bands by a Northern blot analysis for RNA from various SHR tissues indicates that this 3 kb fragment is actively transcribed in vivo.

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The regional brain and spinal cord concentrations of calcitonin gene-related peptide (CGRP) were measured in age-matched (22–23-week-old) spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto (WKY) rats. The highest concentration of CCRP in the WKY rats was in the spinal cord (172 ± 9pmol/g), followed by the medulla oblongata/pons (88 ± 5 pmol/g). The relative order of distribution in the remaining regions was: hypothalamus (12.6 ± 0.8 pmol/g) = striatum > thalamus > midbrain = hippocampus > cortex (2.1 ± 0.3 pmol/g). The concentration of CCRP in the cerebellum was at the level of the assay's sensitivity (0.5 pmol/g). The relative order of distribution in the SHR strain was essentially the same. However, in comparison with the WKY rats, the SHR had significantly lower levels of CGRP in the hippocampus (−47%), striatum (−49%) and medulla oblongata/pons (−24%), and in the spinal cord (−24%). In younger age-matched (16–17-week-old) rats, the spinal cord and medulla oblongata/pons concentrations of CGRP were also lower in SHR than in WKY rats. CCRP is a putative neurotransmitter which, when administered centrally or peripherally, has potent cardiovascular effects. The reduced levels of this peptide may be an important factor in the cardiovascular and/or behavioural abnormalities of the SHR strain.

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We investigated the reliability of calculating the mean blood pressure (MBP) in spontaneously hypertensive rats (SHR) from the systolic and diastolic blood pressures (SBP; DBP), using a form factor, calculated as: (MBP – DBP)/(SBP – DBP). The mean values of this form factor, as determined by blood pressure curve integration, were 0.459 and 0.450 in awake and anaesthetized SHR, respectively. There was no change in the form factor with pulse frequency. When direct femoral artery MBP measurements (x) were compared with MBP values (y) calculated from tail-cuff measurements of SBP and DBP using the form factor, the linear relationship between the two parameters was: y = 0.91x + 1.5 mmHg (r = 0.98). Actually, direct measurements confirmed that the tail artery MBP was 6–7% lower than the femoral artery MBP. In awake Wistar–Kyoto (WKY) rats, the form factor was 0.468. We therefore concluded that an approximate form factor value of 0.46 could be used in rats to estimate the MBP from known values of SBP and DBP. We further suggest that, because pulse pressure in any given rat remains relatively constant with time, SBP and DBP can be estimated in experiments by initially measuring the pulse pressure; thus, only the MBP need be recorded thereafter.

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The role of dietary calcium and magnesium in the development of hypertension was studied in nine groups, each consisting of nine spontaneously hypertensive rats aged 8–31 weeks. The animals were fed AIN 76A semi–purified diets varying in calcium (0.075, 0.5 and 2.5%) and magnesium (0.01, 0.05 and 0.75%) concentrations according to a 3 × 3 factorial design. Dietary calcium and systolic blood pressure were inversely related, significantly (P< 0.05) after 12 weeks. Total and ultrafilterable serum calcium concentrations were also significantly negatively correlated with blood pressure (r = –0.46;P= 0.001 and r = –0.57;P= 0.001, respectively). Repeated measures analysis of variance indicated that dietary magnesium had no effect on systolic blood pressure, and no calcium × magnesium interaction on blood pressure was observed. Signs of magnesium deficiency, calcium deposits in the kidneys, and histological lesions were observed in groups on a high–calcium diet receiving normal and low levels of magnesium. Thus a lowering of blood pressure by calcium supplementation, without concomitant magnesium supplementation, was accompanied by biochemical and histological abnormalities in this animal model.

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Fish and fish oils have been reported to reduce blood pressure in normotensives and untreated hypertensives. The present study examined the effect of dietary supplementation with fish oil on blood pressure in 20 treated hypertensives with controlled blood pressures who continued their usual antihypertensive drug treatment throughout. A double-blind, randomized crossover design was used, with two phases, each of 8 weeks' duration. In one phase, subjects took fifteen 1 g fish oil capsules (Lipitac; Reckitt and Colman Pharmaceuticals, Sydney, Australia) daily, and in the other, 15 capsules of identical appearance containing 1 g olive oil daily. There was no difference between the treatment phases for any blood pressure parameter, heart rate or body weight, but blood pressure was lower in both phases compared with pretreatment values. The fasting plasma triglyceride concentration was 30% lower in the fish oil phase (P< 0.001), but there was no difference between the phases for plasma concentrations of total or high-density lipoprotein (HDL) cholesterol. We conclude that, in treated hypertensives with controlled blood pressures, any additional fall in blood pressure produced by dietary supplementation with fish oil is so small that the requirement for antihypertensive drug therapy is unlikely to be reduced.

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

In this paper we describe a routine method of measuring inactive renin in rat plasma. The activation was performed by trypsin, at optimal concentration and incubation conditions. The trypsin treatment formed an interfering and high-performance liquid chromatography-verified tetradecapeptide-like material, which was removed before the assay by a simple batchwise use of a cation-exchange resin. The concentration of activated inactive renin was measured by an antibody-trapping method after the addition of exogenous angiotensinogen. Angiotensinogen was added in order to compensate for the trypsin destruction of angiotensinogen and in order to measure the parameter of renin concentration. The inactive renin concentration in plasma of conscious male rats was 0.48 ± 0.13 Coldblatt units (GU) per litre (n = 38). This corresponds to 66% (range 42-92%) of the total renin concentration. Physiological experiments in conscious rats were initiated, demonstrating that nephrectomy decreased the inactive renin concentration from 0.45 ± 0.14 to 0.27 ± 0.05 CU/l after 24 h (n = 21;P< 0.01). Submandibular sialoadenectomy decreased the plasma inactive renin concentration from 0.45 ± 0.11 to 0.34 ± 0.06 GU/I (n = 12;P< 0.05) after 7 days. Combined sialoadenectomy and nephrectomy decreased the plasma inactive renin concentration from 0.45 ± 0.11 to 0.24 ± 0.06 (n = 12;P< 0.01).

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The aim of this study was to determine whether the renin inhibitor CP-71362 (Pfizer Central Research, Groton, Connecticut, USA) is capable of inducing sustained reductions in arterial pressure in sodium-depleted dogs and to examine the changes in renal function associated with chronic renin inhibition. In addition, we also examined the chronic effects on renal function and blood pressure of the angiotensin converting enzyme (ACE) inhibitor enalaprilat. Infusion of CP-71362 (1.1 µg/kg per min, intravenously) for 7 days decreased mean arterial pressure from 87 ± 3 to 75 ± 2 mmHg, while causing no significant changes in sodium excretion, the glomerular filtration rate, or effective renal plasma flow. Plasma renin activity was suppressed to undetectable levels throughout the 7 days of CP-71362 infusion. Infusion of enalaprilat (4 mg/kg per day) for 7 days in sodium-depleted dogs decreased mean arterial pressure (from 85 ± 2 to 64 ± 3 mmHg) and renal vascular resistance, and increased effective renal plasma flow and sodium excretion, but caused no significant changes in the glomerular filtration rate. Thus CP-71362 is a potent inhibitor of dog plasma renin, and we observed no waning of this inhibitory effect or CP-71362's hypotensive actions over 7 days. The mechanisms responsible for the differences in the blood pressure and renal responses to CP-71362 and ACE inhibition are not clear, but may be dose-related or due to differences in the distribution of these compounds to various tissues, including the kidney.

ISSN:0263-6352    

出版商:OVID    

年代:1990

数据来源: OVID