bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blood Pressure Response to Central and Peripheral Injection of Angiotensin II and 8-C-Phenylglycine Analogue of Angiotensin II in Rats with Experimental Hypertension
Authors: Schoelkens B. A. , Jung W. , Steinbach R. 
Published: August 2015

1. We have compared the effect of central and peripheral administration of angiotensin II and (1-succinamoyl-5-valine-8-phenylglycine)angiotensin II on blood pressure of male conscious unrestrained rats with normal blood pressure, and with spontaneous hypertension or chronic renal hypertension.
2. After central and peripheral injection of angiotensin II all rats exhibited a significant dose-related increase in blood pressure.
3. Administration of the analogue was without effect in normotensive rats. Ten-weeks-old rats with spontaneous hypertension showed a significant blood pressure decrease after central injection, but an increase after peripheral injection. This centrally induced decrease could not be observed in spontaneously hypertensive rats 14 weeks old. In these animals the analogue increased the blood pressure. In rats with chronic renal hypertension in contrast to peripheral injection, central administration decreased the pressure significantly.
4. Plasma renin activity was not changed after central injection of the analogue in normotensive rats.
5. These observations suggest the participation of the intrinsic brain isorenin-angiotensin system in central blood pressure regulation in these forms of experimental hypertension.
The Role of α- and β-Presynaptic Receptors in the Regulation of Noradrenaline Release Elicited by Nerve Stimulation
Authors: Langer S. Z. 
Published: August 2015

1. Two presynaptic mechanisms appear to be involved in the regulation of noradrenaline release during nerve stimulation. The first one, mediated by β-adrenoceptors, operates at low frequencies of nerve stimulation, leading to an increase in transmitter release. The second one, mediated through α-adrenoceptors, is triggered when higher concentrations of the transmitter are reached in the synaptic cleft, leading to inhibition of transmitter release, probably through a restriction in the availability of calcium for the secretory process.
2. It is postulated that part of the anti-hypertensive effects of drugs like clonidine, α-methyldopa and β-receptor-blocking agents may be related to their long-term effects on presynaptic adrenoceptors.
The Role of Noradrenaline and other Transmitter Hormones in the Pathogenesis of Hypertension
Authors: Louis W. J. , Jarrott B. , Doyle A. E. 
Published: August 2015

1. Studies with a sensitive radioenzymatic assay for plasma noradrenaline suggest there is a selective overactivity of the sympathetic nervous system in essential hypertension.
2. Serotonin turnover in the mesenteric vessels is approximately twice that of noradrenaline and it is suggested that serotonin may interact with noradrenaline to maintain vascular resistance.
3. Methodology which allows the study of local sympathetic turnover in nuclei of the central nervous system and in peripheral blood vessels is described. This approach has been used to study non-innervated sympathetic turnover observed in phaeochromocytoma.
Serum Dopamine β-Hydroxylase Activity in Essential Hypertension
Authors: Aoki K. , Tazumi K. , Yoshida T. , Kato S. , Sato I. , Takikawa K. 
Published: August 2015

1. Serum dopamine β-hydroxylase activity was determined in normotensive control subjects and patients with labile or established essential hypertension. The enzyme activity was 25·9 ± 1·9 (sem), 29·6±2·5 and 25·1 ± 1·9 μmol min—1 1—1, for control, labile and established hypertensive subjects respectively.
2. Neither blood pressure nor serum dopamine β-hydroxylase activity was changed in normotensive control subjects by administration of phentolamine; however, in patients with essential hypertension blood pressure was significantly decreased (P < 0·01) and serum dopamine β-hydroxylase activity was slightly increased. With propranolol administration, blood pressure and the serum enzyme activity were not significantly changed in normotensive or hypertensive subjects.
3. Our results suggest that there is no correlation between serum dopamine β-hydroxylase activity and blood pressure.
Haemodynamic Responses to Exercise and Acute β-Receptor Blockade in Renin Sub-Types of Essential Hypertension
Authors: Burkart F. , Bühler F. R. , Pfisterer M. , Lütold B. E. , Küng M. 
Published: August 2015

1. Haemodynamic and renin responses to dynamic exercise before and after intravenous β-adrenoreceptor blockade with propranolol were compared in twenty-one patients with essential hypertension and either high (n = 7), normal (n = 7) or low plasma renin activity (n = 7).
2. Renin and heart-rate responses to exercise and β-receptor blockade diminished from high-renin to normal and to low-renin patients, effects which were blunted with increasing age.
3. Among the renin groups cardiac output, stroke volume, diastolic pulmonary artery pressure, systemic pressure and peripheral vascular resistance as well as their changes produced by exercise and acute β-receptor blockade were not significantly different.
4. Long-term anti-hypertensive propranolol effects correlated with the pre-treatment renin status, renin stimulation and its suppression by acute β-receptor blockade as well as with the exercise tachycardia and the patient's age.
5. The results suggest different adrenergic control mechanisms in renin sub-types of essential hypertension, age being a modulating factor.
Effects of Intravenous Labetalol on Blood Pressure, Angiotensin II and Aldosterone in Hypertension: Comparison with Propranolol
Authors: Rosei E. A. , Trust P. M. , Brown J. J. , Fraser R. , Lever A. F. , Morton J. J. , Robertson J. I. S. 
Published: August 2015

1. Labetalol, a compound with both α- and β-adrenoreceptor-blocking actions, was given intravenously (1·5–2·0 mg/kg) in twenty recumbent hypertensive patients.
2. There was a rapid reduction in systolic and diastolic pressures in all, maintained up to 24 h in some subjects.
3. Severe hypotension was not seen in recumbent subjects, but postural hypotension was common.
4. Labetalol caused significant lowering of heart rate.
5. Labetalol induced significant and related lowering of plasma angiotensin II and aldosterone concentrations, most obviously when these were initially high.
6. In a cross-over comparison in five patients against 10 mg of propranolol intravenously, labetalol was more effective in lowering blood pressure, but less effective in lowering pulse rate or plasma angiotensin II.
Combined α- and β-Adrenoreceptor Blockade in Hypertension: A Controlled Trial of Labetalol (AH 5158) Compared with Propranolol and Placebo
Authors: Pugsley D. , Armstrong B. , Nassim M. , Beilin L. J. 
Published: August 2015

1. Labetalol (AH 5158) is a new drug which has both α- and β-adrenoreceptor antagonist activity. Labetalol has been compared with propranolol and placebo for the treatment of mild to moderate hypertension (150/100 to 189/114 mmHg), in a double-blind cross-over trial with three 10 week treatment periods.
2. Both drugs reduced blood pressures in nine of the ten patients who have completed the trial. Relative to placebo labetalol caused decreases in supine pressures similar to those caused bypropranolol (average −10/ −10 and −10/ −9 mmHg respectively), with a greater effect on standing (labetalol −20/ −19; propranolol −8/−12 mmHg; P < 001) and after exercise (labetalol −27/−18 and propranolol −16/−14 mmHg).
3. Labetalol and propranalol caused a similar fall in supine pulse rate (−11/min and −13/min respectively), but there was less bradycardia on standing (labetalol −11/min; propranalol −18/ min; P < 0001) and after exercise (labetalol −17/min; propranolol −23/min; P < 0·001).
4. The average dose ratios of labetalol to propranolol was 2·4:1 (w/w).
5. These results suggest that the effect of labetalol on blood pressure involves both α- and β-adrenoreceptor antagonist properties.
6. Further evaluation of labetalol is warranted as it may have some advantages in respect of producing less bradycardia, improved peripheral blood flow and less effect on airways resistance than ‘pure’ β-receptor-blocking agents.
The Anti-Hypertensive Efficacy of Combined α- and β-Adrenoreceptor Blockade with Phentolamine—Oxprenolol or with Labetalol (AH 5158)
Authors: Johnson B. F. , Labrooy J. , Munro-Faure A. D. 
Published: August 2015

1. The interaction of phentotamine with the β-receptor blocker oxprenolol was studied in a controlled trial.
2. The combination was generally well tolerated.
3. Oxprenolol alone produced modest but significant reductions in supine, standing and post-exercise blood pressures. Small reductions were seen only with sustained phentolamine administration.
4. The combined effect of the two drugs appeared to be additive only at the lower doses of oxprenolol.
5. Labetalol produced significantly greater reductions in supine and standing blood pressure than combined oxprenolol—phentolamine. At a daily dose of 400 mg, postural hypotension was not seen, though transient symptoms were frequent.
Comparative Anti-Hypertensive Effectiveness of β-Adrenoreceptor Antagonists with Different Pharmacological Properties: Dose—Response Studies during Acute and Chronic Administration
Authors: Taylor S. H. , Davidson C. , Singleton W. , Thadani U. 
Published: August 2015

1. Immediate and long-term blood pressure-lowering activity of five β-adrenoreceptor antagonists with different ancillary pharmacological properties were compared in a randomized double-blind placebo controlled factorial trial in twenty-five previously untreated patients with stable uncomplicated essential hypertension.
2. In doses which produced similar reductions in exercise tachycardia, all drugs exerted similar antihypertensive activity, which was greater on systolic than diastolic pressure and greatest during exercise.
3. These effects were maximum within an hour and lasted for over 8 h after a single oral dose.
4. Blood pressure-lowering activity, particularly the reduction in exercise systolic pressure, was significantly related to the logarithm of the dose of each drug.
5. Anti-hypertensive activity was maximally enhanced after 4 weeks of sustained treatment at any given dose. There was no short-term habituation to treatment and substitution with placebo resulted in a return of the blood pressure to pretreatment values within 4 weeks without subsequent overshoot.
6. The blood pressure-lowering activity of these drugs was predominantly related to their common property of competitive antagonism of cardiac β-adrenoreceptors; their ancillary pharmacological properties, with the exception of intrinsic vasodilator activity, played little part in this response.
Comparison of a Slow-Release Formulation of Oxprenolol with Conventional Oxprenolol in the Treatment of Hypertension
Authors: O'brien K. P. , Stephens E. J. W. 
Published: August 2015

1. Patients with moderate to severe hypertension were studied during a 12 weeks period, while taking a slow-release formulation of oxprenolol once daily, in a dose equal to their previous total daily dose of oxprenolol given in divided doses.
2. There were no significant differences between blood pressure at the beginning and end of the 12 weeks period.
3. Once-daily dosage offers advantages of patient compliance.
Vasodilating Drugs: Contrasting Haemodynamic Effects
Authors: Tarazi R. C. , Dustan H. P. , Bravo E. L. , Niarchos A. P. 
Published: August 2015

1. We investigated the haemodynamic effects of intravenously administered hydrallazine, diazoxide and nitroprusside and orally administered minoxidil to determine whether vasodilators (such as nitroprusside) which do not increase cardiac output might be better treatment for hypertensive complications associated with, or caused by, myocardial failure than those that do.
2. Hydrallazine and diazoxide caused increases in heart rate, cardiac output, cardiopulmonary blood volume, the ratio of cardiac output to cardiopulmonary volume, and pulmonary artery pressure. Nitroprusside, although decreasing pressure and vascular resistance, caused no significant change in the other functions except for reducing pulmonary artery pressure. Minoxidil, when given orally, had the potential for causing pulmonary hypertension. This seemed explained by increased flow (hyperdynamic type) in some but by congestive cardiac failure in others; the latter condition was probably intensified by the marked fluid retention that the drug can cause.
3. On the basis of these results a classification of vasodilators was constructed which depends on the presence or absence of a venodilating effect. Vasodilators which produce no (or little) venodilatation, increase heart rate, cardiac output, cardiopulmonary blood volume and pulmonary artery pressure. In this class are diazoxide, hydrallazine and minoxidil. Those that cause venodilatation do not stimulate the heart nor do they cause pulmonary hypertension. Nitroprusside and nitroglycerine are drugs of this type.
4. These results suggest that drugs producing both venodilatation and arteriolar dilatation may be more specific therapy for hypertensive complications associated with cardiac failure than those that cause only arteriolar dilatation.
Cardiovascular Effects of Prazosin in Dogs
Authors: Cavero I. 
Published: August 2015

1. In pentobarbitone-anaesthetized dogs, prazosin (2×1·3 μmol day—1 kg—1; 2×0·5 mg day—1 kg—1) administered orally for 3 days reduced resting aortic blood pressure as well as the pressor response to bilateral carotid occlusion. Prazosin neither affected resting heart rate nor the tachycardia induced by intravenous isoprenaline, noradrenaline and electrical stimulation of preganglionic and postganglionic sympathetic nerve fibres. Prazosin significantly attenuated the fall in perfusion pressure in a perfused hind leg resulting from the section of the ipsilateral sympathetic lumbar chain. Furthermore, the drug inhibited by about 50% the hind-leg pressor responses elicited by intra-arterial administration of α-adrenoreceptor agonists and by stimulation of the lumbar sympathetic chain, without altering the effects of angiotensin II.
2. Acute administration of prazosin into the innervated hind leg provoked a dose-related reduction in vascular resistance. However, after spinal anaesthesia no such an effect was observed even when vascular tone was increased by infusion of vasopressin. Under the same experimental conditions administration of papaverine induced a vasodilatation.
3. This study confirms that prazosin impairs the function of vascular α-adrenoreceptors, and strongly challenges the claim that this compound produces a directly mediated vasodilatation of the leg vascular bed.
A Study of the use of Prazosin in Hypertensive Patients in Korea
Authors: Kim J. S. 
Published: August 2015

1. The effects of prazosin administered alone or in combination were studied in thirty patients between August 1974 and March 1975.
2. All patients had previously received treatment for hypertension with other agents, for from 2 months to 10 years. All thirty patients had refractory hypertension which had not responded satisfactorily to other treatment.
3. Patients were treated initially with prazosin; polythiazide, or polythiazide plus tolamolol, were added when necessary.
4. A satisfactory blood pressure response to prazosin alone, or prazosin in dual or triple combination therapy, occurred in all thirty patients.
5. Prazosin was well tolerated.
Alcohol use, Hypertension and Coronary Heart Disease
Authors: Mathews J. D. 
Published: August 2015

1. Male death rates from hypertension and stroke in England and Wales in 1949–53 were highest in those socio-economic and occupational groups with the highest death rates for cirrhosis of the liver (and presumably with highest alcohol intake).
2. In prevalence data from the Busselton population in Western Australia in 1969, there was a significant association between hypertension and a history of heavy drinking.
3. Together with other data, these observations suggest that up to 30% of hypertension in affluent countries may prove to be attributable to the use of alcohol.
A 40 Years' Follow-up Study of 1000 Untreated Hypertensive Patients
Authors: Bechgaard P. 
Published: August 2015

1. This study includes 1038 patients (325 men and 713 women) who consulted the medical out-patient clinic, Rigshospitalet, Copenhagen, during the years 1932–38. All these patients had a blood pressure of 160/100 mmHg or 180 mmHg or more.
2. The average age at the first examination was 54 years; 97% were followed at intervals of 10 years until 1975, when sixty patients were still alive. Treatment was minimal until 1970.
3. Sixty per cent of the men and 76% of the women reached an age of 65 years or more. Nine per cent of the total patients lived to 85 years or more. Excess mortality was far higher in men than in women.
4. Causes of death were stroke in 17%, heart failure in 24%, coronary occlusion in 16%, uraemia in 4% and other diseases in 39%. At the first examination thirteen cases of malignant hypertension were registered, none at later sessions.
Thrombolysis by Ultrasound
Authors: Trübestein G. , Engel C. , Etzel F. , Sobbe A. , Cremer H. , Stumpff U. 
Published: August 2015

1. A new method of destroying thrombi in blood vessels by ultrasound and simultaneously removing them is reported.
2. Experiments were performed in twenty dogs with artificial thrombi in the iliac and femoral arteries and veins. The length of the thrombi ranged from 4 to 5 cm and the age from 12 h to 10 days. The unit used consisted of a generator, a frequency counter, an ultrasonic transducer with the hollow waveguide and a vacuum pump. For protection of the vessel wall the guide is surrounded by a plastic tube. The ultrasonic frequency is 26·5 kHz, the amplitude 25–30 μm. The time needed to destroy the thrombus by ultrasound and suck out the thrombotic material ranged from 2·5 to 5 min.
3. To check side effects, experiments were performed in forty-four dogs. No significant changes were seen in the fibrinolytic system or microscopic structure of the vessel wall after ultrasound.
Increased Renal Function in Patients with Acute Left Ventricular Failure: A Possible Homeostatic Mechanism
Authors: Bennett E. D. , Brooks N. H. , Keddie J. , Lis Y. , Wilson A. 
Published: August 2015

1. Creatinine clearance and urine excretion have been measured in fifty-five patients admitted with suspected myocardial infarction. Patients were grouped on the basis of their radiological report on the first day, irrespective of their diagnosis. The first group consisted of twenty-six patients with normal chest X-rays, the second group of twenty-two patients with radiological evidence of upper zone vessel dilatation and the third group of seven patients with radiological evidence of pulmonary oedema, who were significantly older.
2. The mean creatinine clearance on the first day in patients with upper zone vessel dilatation was significantly higher than the creatinine clearance in patients with normal radiographs. By the third and fourth days the clearances were similar in both groups. The patients with pulmonary oedema had low creatinine clearances on all 4 days.
3. Glomerular filtration rate was measured with 51Cr-labelled EDTA on twenty occasions, and the results correlated well with the creatinine clearance values obtained on the same day.
4. The mean urine volumes on day 1 (2245 ± 286 ml/24 h) and day 2 (2219 ±232 ml/24 h) in patients with upper zone vessel dilatation who had not received diuretics, were significantly higher (P < 001) than the urine volumes on day 1 (1652 ± 145 ml/24 h) and day 2 (1713 ± 118 ml/24 h) in patients with normal radiographs. All the patients with pulmonary oedema had received diuretics during the study and were therefore excluded from this analysis.
5. It is concluded that patients with radiological evidence of upper zone vessel dilatation show an elevation of glomerular filtration rate and an increase in urinary output. It is suggested that these responses are mediated via the stimulation of receptors in the left side of the heart and fulfil a homeostatic function, to unload an overdistended heart.
The Development of a Radioimmunoassay Procedure for the Estimation of Tamm—Horsfall Glycoprotein in Human Serum
Authors: Avis P. J. G. 
Published: August 2015

1. A quantitative radioimmunoassay was developed for the measurement of nanogram amounts of Tamm—Horsfall (TH) glycoprotein in the presence of serum proteins at concentrations above 30 mg/ml.
2. Specific anti-(TH-glycoprotein) antibodies were labelled with 125I and these were usable for a period of 8 weeks.
3. Agarose beads (Sepharose 4B), to which TH-glycoprotein had been coupled via cyanogen bromide activation of the Sepharose, were used as the solid phase in the assay. This proved stable upon storage at 4°C for periods in excess of 4 months.
4. The dissociation of the glycoprotein in the presence of serum proteins that was necessary for quantification was achieved by subjecting the sample to ultrasonication.
5. Assays conducted on a small sample of normal serum produced evidence that normal serum contained amounts (50–180 ng/ml) of a substance that reacted similarly to TH-glycoprotein in the assay procedure and in a series of experiments conducted to confirm the presence of this substance in human serum.
Effect of Nephrectomy and Enterectomy on Plasma Clearance of Intravenously Administered Dipeptides in Rats
Authors: Adibi S. A. , Krzysik B. A. 
Published: August 2015

1. Sham-operated and bilaterally nephrectomized rats were injected intravenously with glycyl-l-leucine, glycylglycine and glycylsarcosine, and the concentrations of these dipeptides in plasma and muscle, liver, renal cortex (in the sham-operated rats) and intestinal mucosa at various intervals were determined.
2. Initially the plasma concentrations of glycyl-leucine and glycylglycine were higher in nephrectomized than in control rats but later the concentrations were similar in both groups of rats. The disappearance of these two dipeptides from plasma was almost complete within 20 min, and their plasma half-lives were not changed remarkably by nephrectomy. In contrast, nephrectomy markedly impaired disappearance of glycylsarcosine from plasma and prolonged its half-life from 7·6 min to 52·0 min.
3. Glycyl-leucine and glycylglycine were not detected in tissues of control rats injected with these dipeptides, but glycylsarcosine was recovered from all four tissues examined. Nephrectomy resulted in greater accumulations of glycylsarcosine in tissues and the appearance of glycylglycine in the remaining three tissues and glycyl-leucine in muscle.
4. Enterectomy did not have a remarkable effect on plasma half-life of glycylglycine but it allowed recovery of this dipeptide from renal cortex, liver and muscle.
5. It is concluded that kidneys and small intestine are involved in the disposition of circulating dipeptides, but in their absence other tissues may assume a greater role in this regard. However, renal clearance appears to be an important route for the disposition of dipeptides which are poorly hydrolysed by body tissues.