摘要:

b1. The relation between workload and the antihypertensive effect of exercise therapy in hypertensive patients, and the mechanism of that effect, were investigated.2. Twenty‐six patients participated in the study and were randomly assigned to 10 weeks of either low or high workload exercise. In the low workload group, 16 mild hypertensive patients were treated with bicycle ergometer exercise at approximately 50% of their maximum oxygen consumption (V̇O2max) for 60 min three times a week for 10 weeks. In the high workload group, 10 mild hypertensive patients exercised on the same schedule, but at approximately 75% of V̇O2max.3. After 10 weeks of exercise, the low workload group had significantly lower systolic (9 mmHg), mean (6 mmHg) and diastolic (6 mmHg) blood pressures. In the high workload group, decreases in systolic (3 mmHg), mean (4 mmHg) and diastolic (5 mmHg) blood pressure were not statistically significant.4. In the low workload group, changes in haemodynamic and humoral variables were not significant, except for a reduction in plasma norepinephrine at week 7. Cardiac index and plasma norepinephrine tended to decrease. In the high workload group, plasma norepinephrine and the renin‐angiotensin system were transiently stimulated after 4 weeks of exercise. Stroke volume significantly increased (+26.4%) after 10 weeks of high workload exercise.5. Based on these results and better patient compliance with the exercise programme in the low workload group than in the high workload group, low workload exercise therapy was recommended to mild hypertensive pat

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00492.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

b1. The role of the presynaptic adrenoceptor subtypes in man was investigated based on observation of the changes in blood pressure (ΔBP) and plasma noradrenaline concentration (ANA) with the cold pressor test (CPT).2. The CPT was well reproducible for BP and NA when performed at a 2 week interval in patients with mild hypertension.3. After administration for 4 weeks, guanfacine (Gf; (α‐adrenoceptor agonist) decreased the ΔNA response to CPT.4. After administration for 2 or 4 weeks, bunazosin (Bu; α1‐adrenoceptor antagonist) atenolol (At; β1‐adrenoceptor antagonist) and nadolol (Nd; non‐selective β‐adrenoceptor antagonist) did not affect the ΔNA response to CPT.5. Both Gf and Bu decreased the systolic blood pressure response (ΔSBP) to CPT after 4 weeks of the administration. Neither At nor Nd significantly changed the ΔSBP response to CPT.6. It is likely that Gf stimulated the presynaptic α2adrenoceptors at the sympathetic nerve endings as well as the central α2adrenoceptors, inhibiting the release of noradrenaline. It is unlikely that Bu, At and Nd exerted any clearly defined action on the presynaptic adrenoceptors in human h

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00493.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

b1. The effects of acute bilateral superior cervical ganglionectomy on cerebral blood flow and metabolism were investigated in stroke‐prone spontaneously hypertensive rats (SHRsp), before and during cerebral ischaemia.2. The resting cerebral blood flow was comparable between the control and denervated animals.3. There was no significant difference in cerebral blood flow or concentration of tissue energy metabolites (adenosine triphosphate [ATP], lactate and pyruvate) between the sham‐operated control and denervated animals during ischaemia.4. The results suggest that sympathetic innervation of cerebral vessels originating from superior cervical ganglia may not play a major role in the progression of cerebral ischaemia in SH

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00494.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. Previous experiments have shown that the level of sialic acid in the epididymis is influenced by factors originating in the testis.2. To exclude interference from these factors, both orchidectomized and duct‐ligated rats were used to study the potential role of prolactin in the epididymis.3. When ovine prolactin was injected in orchidectomized rats, a dose‐related increase in the level of sialic acid was observed in the epididymis.4. That this action of prolactin is independent of androgen was confirmed by studies using bromocryptine, which decreases circulating endogenous prolactin.5. The physiological role(s) of epididymal sialic acid production in response to prolactin remain to be establis

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00495.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. Basal and haemorrhage‐stimulated erythropoietin (Epo) and ACTH levels were measured in the chronically cannulated immature ovine foetus (130 days) ovine foetus, but were lower than those observed in the neonatal lamb.3. In control foetuses (Protocol 1) the small degree of haemorrhage associated with the sampling procedure increased the plasma Epo values from 11.4 ± 3.0 (n= 5) mU/mL to 23.8±4.3 mU/mL at 24 h (mean ± s.e.m.). There was a significant monotonic increase with time (F= 16.4; d.f. 1,19;P= 0.001). An initial haemorrhage of approximately 10% blood volume (Protocol 2) increased plasma Epo values from 7.3±2.3 to 24.2 ± 7.1 mU/mL(n= 3).4. Haemorrhage of 20% fetal blood volume (Protocol 3) produced an increase in plasma Epo from 9.3±1.7 to 54.7 ± 15.5 mU/mL at 6 hand to 57.6 ± 7.3 mU/mLat24 hn= 5). By repeated measures ANOVA, the effect of the 20% haemorrhage was significant when compared with the control group (F= 7.32, d.f. 2, 16,P= 0.006). There was a significantly greater decrease in haematocrit (F= 6.7, d.f. 2, 20,P= 0.004) and haemoglobin (F= 5.0, d.f. 2, 20,P= 0.013) in animals of Protocol 3 than in those of Protocol 1.5. Fetal blood gases and plasma adrenocorticotropic hormone (ACTH) did not alter with haemorrhage, indicating the tolerance of the foetus to this degree of ha

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00496.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. To clarify the role of platelet‐activating factor (PAF) in the development of adult respiratory distress syndrome (ARDS), we performed bronchoalveolar lavage (BAL) in 19 patients with ARDS and examined cell populations, albumin concentrations and PAF levels. PAF levels were measured by a newly developed radioimmunoassay.2. In the BAL fluid of ARDS patients, neutrophil percentages and albumin concentrations markedly increased compared with control subjects.3. PAF was detected in 14 of 19 patients with ARDS, whereas it did not exist in the control subjects.4. Furthermore, we investigated the priming effect of recombinant human tumour necrosis factor‐α (TNFα), which is known to be one of the most important mediators in the development of ARDS, on PAF production induced by the calcium ionophore in neutrophils.5. Pre‐incubation with TNFαdose‐dependently increased both extracellular and intracellular PAF production in neutrophils.6. These results suggest that PAF might play an important role in the developme

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00497.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. The effects of dopamine and dobutamine on the pulmonary haemodynamic response to hypoxia were studied in nine anaesthetized dogs under hypoxaemia induced by ventilation with hypoxic gas mixture.2. From the present study, only dopamine infusion reduced arterial oxygenation during hypoxic hypoxaemia, whereas catecholamine maintained it at the same level during normoxaemia.3. A redistribution of perfusion to the pulmonary vasculature may be related to a reduction of arterial oxygenation with dopamine infusion during hypoxic hypoxaemia.4. It is presumed that an increase in pulmonary blood flow would emphasize an inhibition of hypoxic pressor response in the pulmonary vasculature, which may not be a direct effect of dopamine.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00498.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. The effect of inhibition of nitric oxide biosynthesis using N‐nitro‐l‐arginine (NOLA) was examined in conscious rabbits and rabbit isolated aortae.2. In autonomically blocked conscious rabbits intravenous infusion of NOLA (15 mg/kg) significantly increased arterial pressure and hindlimb vascular resistance but did not affect heart rate. Depressor and hindlimb vasodilator responses to acetylcholine (3–12 μg/kg per min) were significantly attenuated in the presence of NOLA. In contrast, NOLA significantly enhanced responses to intravenous infusion of glyceryl trinitrate (10–40 Mg/kg per min)in vivo.3. Infusion of noradrenaline (1–4 μg/kg per min) or the release of neuronal noradrenaline in response to the infusion of tyramine (80–320 Mg/kg per min) increased arterial pressure and hindlimb vascular resistance in autonomically blocked conscious rabbits. After the administration of NOLA, the vasoconstrictor responses to both noradrenaline and tyramine were significantly enhanced.4. In isolated rabbit aortae, NOLA (10 μmol/L) significantly impaired relaxant responses to acetylcholine but did not affect responses to glyceryl trinitrate. NOLA enhanced contractile responses to the adrenoceptor agonists noradrenaline and phenylephrine but did not affect the contractile responses to the thromboxane‐mimetic U46619.5. These data indicate that in autonomically blocked conscious rabbits, NOLA causes systemic vasoconstriction, impairs dilator responses to acetylcholine and enhances dilator responses to glyceryl trinitrate. In addition, NOLA enhances constrictor responses to both exogenous and neuronally‐released noradrenaline. These results suggest that nitric oxide is important in the regulation of normal vascular tone and in the modulation of vascular responses to vasodilator and va

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00499.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARYThe present study was designed to investigate the presynaptic α2‐adrenoceptor function to inhibit norepinephrine (NE) release in blood vessels of reduced renal mass salt hypertensive rats (Na‐loaded HT). Isolated perfused mesenteric vasculatures were prepared from Na‐loaded HT and normotensive control rats (NT‐control), and the NE release and vascular responsiveness were examined. Periarterial nerve stimulation caused a significantly greater release of NE and pressor responses in Na‐loaded HT than in NT‐control. Yohimbine, a potent α‐adrenoceptor antagonist, demonstrated the facilitatory effects on NE release during nerve stimulation. The effects were significantly attenuated in Na‐loaded HT compared with NT‐control.These results demonstrate that vascular sympathetic nervous activity might be enhanced in Na‐loaded HT. Furthermore, the increased NE release from vascular adrenergic neurons in Na‐loaded HT could partially depend on impaired presynaptic α2‐adrenoceptor‐mediated modulation, which might contribute to the pathogenesis and maintenance of this form of

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00500.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SUMMARY1. The hepatic reticuloendothelial cell population is generally assumed to increase in size, along with the liver, during ageing in rats. However, this has not been rigorously established.2. Using electron microscopy and stereological techniques, the present study has shown that the volume densities of hepatocytes and Kupffer cells (and probably also of endothelial cells, fat storing cells and the extracellular space) of the livers of female Sprague‐Dawley rats are the same at 2 and 24–25 months of age.3. This result indicates that the increase in size of the liver during ageing in the rat is associated with an equivalent increase in the volume of each cell population and the extracellular sp

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1992.tb00501.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY