摘要:

This bibliography is produced in association withCurrent Opinion in Cardiology(Gower Academic Journals Ltd, UK) and is compiled from over 150 journals (theses are listed at the end of the bibliography in this issue). Each issue of theJournal of Hypertensionwill list papers relevant to hypertension, published over a one-month period. A cumulative bibliography, covering 12 months and arranged under subject headings, will appear in the first issue (January) each year. A complete, updated list of the journals scanned will be published at the same time as the cumulative bibliography.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Calcium blockers may reduce contractility of vascular smooth muscle as well as that of myocardial cells. Therefore, falls in both total peripheral vascular resistance (TPR) and cardiac output (CO) might be responsible for a fall in blood pressure (BP) caused by calcium blockers in essential hypertension. We have studied the acute and chronic haemodynamic effects of nisoldipine (a new calcium blocker) in 19 patients with essential hypertension at rest in the supine and sitting positions and during 100-W dynamic exercise to investigate whether CO might be compromized by acute and chronic calcium blockade. Intra-arterial pressure, CO (by Cardiogreen), stroke volume, heart rate and TPR were measured hourly after the first dose of 10 mg nisoldipine (acute study) and then after 1 year of nisoldipine treatment (mean dose 25 mg; chronic study). The maximal first dose response was seen after 1 h, i.e. a fall in intra-arterial pressure (9%) and TPR (19%) and a reflex rise in heart rate (9%) and CO (12%). The effects levelled off during the next 2 h. After 1 year of treatment there was a more marked reduction in BP: at rest intra-arterial pressure fell (14% supine, 16% sitting) due to fall in TPR (19%) but without significant changes in heart rate or CO; during 100-W exercise, intra-arterial pressure fell (14%) due to reduction in both TPR (7%) and CO (6%). In conclusion, nisoldipine lowers BP by reducing TPR, both acutely and chronically. The initial reflex tachycardia and rise in CO disappear during long-term treatment, probably due to resetting of the baroreceptors. After chronic treatment a small reduction in CO contributes to the hypotensive effect during exercise. Since the filling pressure was not measured it is not known whether this is due to a small negative inotropic effect or to other mechanisms.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Angiotensin converting enzyme (ACE) activity was examined in large arteries and veins of rats and found to be present in most of the arteries and to a lesser extent in the veins, except for the femoral vessels which showed higher ACE activity in the vein than in the artery. For the aorta and all its branches, ACE activity was higher in the aorta and its branches in spontaneously hypertensive rats (SHR) than in age-matched normotensive Wistar-Kyoto rats (WKY), with the exception of the hepatic, pulmonary and basilar arteries where the levels were similar for SHR and WKY. For the vena cava and brachial vein, ACE activity was also higher in SHR than WKY but for most other veins the activity was the same with the exception of the pulmonary vein where ACE activity was higher in WKY. The acute treatment of SHR with cilazapril, an ACE inhibitor (0.3 and 3 mg/kg orally, for 4 h) decreased aortic blood pressure and ACE activity in arterial and venous mesenteric and renal vessels in a dose-dependent fashion. Cilazapril, at the threshold hypotensive dose, markedly decreased ACE activity in each pair of aortic segments, carotid, pulmonary, subclavian, brachial and femoral vessels to a degree which was equivalent to that caused by the high dose. The effect outlasted a fall in blood pressure 24 h later. This was associated with a marked decrease in plasma angiotensin II and III and accumulation of angiotensin I at 4 h. No increase in plasma bradykinin or kallidin levels was detected. These findings suggest that the pronounced and prolonged decrease in ACE activity in major vessels may be related to an increase in distensibility rather than to a fall in blood pressure.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

A low-cost ambulatory blood pressure measuring device has been developed from a commercially available stationary apparatus. The device, which has been compared for accuracy with a mercury manometer, has functioned satisfactorily as an ambulatory monitor for 4 years. To minimize errors, blood pressure readings were made in the sitting position at half-hourly intervals over the waking day. The utility of the device in clinical trials has been investigated. On repeated readings no placebo effect on blood pressure was detectable and the mean difference between two readings in 42 subjects was 1.9/ −0.33 mmHg. The standard deviation of the difference were 8.1/5.6 mmHg. This should make it possible to detect differences of 8/5 mmHg between two treatments in about 16 subjects. There was no detectable tendency for blood pressure to change during the day but the variability between readings was substantially increased if the observation periods were reduced to 4 h.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Blood pressure was measured indirectly (using the tail-cuff method) and intra-arterially in conscious rats following one of three experimental procedures carried out in order to determine which resulted in the most marked and reproducible form of adrenal regeneration hypertension (ARH). All rats were unilaterally adrenalectomized and given NaCI solution (1%). In some rats, the remaining adrenal gland was either enucleated (AE rats) or compressed (AC rats) but both kidneys were left intact. During the fourth week after surgery, indirectly measured systolic blood pressure was higher in AE and AC rats than in sham-operated (SO) rats but, when measured intra-arterially, the magnitude of the developed hypertension was small (AC rats) or was absent altogether (AE rats). However, when a kidney was removed at the time of enucleation (AEN rats), the levels of systolic blood pressure, measured indirectly or intra-arterially, were markedly and consistently higher than in the corresponding group of uninephrecto-mized SO rats. The magnitude of the developed hypertension was similar in mature male and immature female AEN rats. We conclude that mature male rats, unilaterally nephro-adrenalectomized and given NaCI solution (1 %), provide a marked and reproducible model of ARH.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Previous investigations have shown that an excitotoxic lesion of the medial prefrontal cortex (MPFC) in normotensive Sprague-Dawley rats results in a reduction in the sensitivity of the baroreceptor heart rate reflex. The aim of this study was to examine the importance of the MPFC in regulation of the heart rate reflex in conscious, unrestrained spontaneously hypertensive rats (SHR). The MPFC was lesioned by bilateral microinfusions of the excitotoxin N-methyl-D-aspartic acid (NMDA). Baroreceptor heart rate reflex testing was performed by measuring reflex heart rate changes in response to blood pressure alterations induced by nitroprusside and phenylephrine with subsequent computerized sigmoidal curve-fitting of the data. Lesion of the MPFC did not significantly alter resting, systolic and diastolic blood pressure, heart rate or baro-reflex parameters (gain, thresholds, range or plateaus). These observations suggest that the putative descending facilitatory influence from the MPFC to brainstem areas, involved in baroreceptor reflex regulation observed in normotensive rats, may be defective in SHR.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The aim was to investigate the contribution of the kidneys and the extrarenal tissues to the concentration of inactive renin in the circulation. Renin was determined in plasma from normal, conscious, male mice in strains with low (BALB/c) and high (Theiller) renin content in the submandibular glands. In untreated, conscious males, inactive and active renin concentration in plasma was 24.9 GU/I (range 13.6–40.1 GU/I) and 4.2 GU/I (0.6–8.8 GU/I), respectively in the BALB/c strain (n = 28). These values were not significantly different from the concentrations of inactive (29.2 GU/I, range 15.6–88.3 GU/I) and active (5.1 GU/I, range 1.9–10.4 GU/I) renin in Theiller's strain (n = 10). Thus, inactive renin comprised 80–90% of the total renin in plasma from normal, conscious, male mice of both strains. The percentage of inactive renin was similar to that found in humans. Following sialoadenectomy and bilateral nephrectomy, the plasma concentration of inactive renin was unchanged.The effect ofin vivoinhibition of the protein synthesis by intraperitoneal injection of emetine was also investigated. After 6 h of inhibition, inactive renin in plasma declined from 21.0 to 9.9 GU/I in normal mice. In contrast, inactive renin was unchanged in sialo-adenectomized and nephrectomized mice (29.1 versus 28.6 GU/I).Our findings suggest that the kidneys are the main source of inactive renin in the circulation. The data also indicate that the kidneys simultaneously secrete and remove inactive renin from the blood at approximately the same rate. The results do not lend support to the concept of activation of inactive renin in the blood, nor to the postulated substantial uptake of inactive renin by extrarenal tissues.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The relative importance of salt intake and psychosocial stimulation in the development of high blood pressure has been studied in colonies of CBA/USC mice. Approximately 50 males were observed for 3–4 months in five population cages which successfully induced chronic psychosocial interaction, resulting in chronic hypertension. Under these conditions, progressive arteriosclerosis develops together with myocardial hypertrophy, increased catecholamine synthesis and increased angiotensin sensitivity. Previous work indicates that this condition shows the characteristics of renin dependent human hypertension. A special grain based diet was used which included 0.014% sodium. This resulted in the ingestion of the equivalent of 40 mmol/l sodium or 3.0 g NaCl in a 70-kg man. This, and an even more stringent synthetic diet containing < 0.01 % NaCl, i.e. < 2 g NaCl per day in man, were contrasted with the standard chow which contains 0.4% sodium.Over 4 months of social interaction the psychosocial stimulation proved to be the critical factor and, despite the low-salt intake, blood pressure rose to the same levels as those of control groups on a normal diet containing 1 % salt. Hypertension occurs in the absence of kidney failure as assessed by blood urea. Plasma renin levels on the low-salt grain based diet were double those on standard chow, showing that the diet was sufficiently low in salt to activate the renin-angiotensin system.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The effects of essential fatty acid deficiency (EFAD) on vascular reactivity to vasoconstrictor stimuli were studied in rat autoperfused hindquarters. Weanling male Sprague-Dawley rats (aged 21 days) were fed diets containing 8% (weight/weight) of stearax plus 2% safflower oil (control diet) or 10% stearax (EFAD diet) for 8 weeks. There was no difference in systemic blood pressure or body weight between the two groups. Basal production of immunoreactive 6-keto-PGF1αby aortic segments was much less in EFAD aortae than in control aortae. In contrast, immunoreactive 6-keto-PGF1αproduced by incubating aortic segments with exogenous arachidonic acid (12 μmol/l) was much greater in EFAD aortae than in control aortae. Moreover, conversion of [14C]-arachidonate to [14C]-6-keto-PGF1αwas more pronounced in EFAD aortae than in control aortae. Vasoconstrictor responses to noradrenaline (0.01–1.0 μmol/l) and angiotensin II (0.001–1.0 μmol/l) infused into the blood perfused hindquarters were then examined. The rats on the EFAD diet were more sensitive to both noradrenaline and angiotensin II than rats on the control diet (P< 0.05, two-way ANOVA). Thus, a deficiency of essential fatty acids can lead to increased vascular sensitivity to vasoconstrictor stimuli. Deficiency of arachidonic acid in phospholipid stores is also accompanied by augmented cyclo-oxygenase activity in the vessel wall, similar to that observed previously in spontaneously hypertensive rats (SHR) and rats with one kidney renovascular hypertension.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID