bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blood Pressure Effects of Endogenous Brain Angiotensin in Rats are Increased by Inhibition of Prostaglandin Biosynthesis
Authors: Schölkens B. , Steinbach R. , Ganten D. 
Published: August 2015

1. In Sprague—Dawley rats experiments were carried out to evaluate the influence of prostaglandins (PG) on the local generation of angiotensin (ANG) from brain angiotensinogen in cerebrospinal fluid and on the blood pressure effects of brain ANG.
2. In rats, pretreated with the PG biosynthesis inhibitor indomethacin (5 mg/kg subcutaneously every other day for 10 days), hog kidney renin was injected in doses of 0·001, 0·01 and 0·1 unit into the lateral brain ventricle.
3. At 15 min after the renin injections cerebrospinal fluid concentrations of ANG I and ANG II were markedly increased in a dose-dependent manner in the indomethacin-treated and in the untreated groups. At 60 min after the injection of renin ANG I concentrations decreased in both groups. However, the fall in ANG I in cerebrospinal fluid was more marked in indomethacin-pretreated animals.
4. Renin in doses of 0·001, 0·01 and 0·1 unit was injected into the lateral brain ventricles of unanaesthetized normotensive rats. A dose-dependent, long-lasting (&gt; 2 h) increase in blood pressure of 9, 15 and 20% was observed. In conscious rats pretreated with indomethacin the blood pressure effects of the renin were greater (12, 23, 27%) when compared with results for untreated controls.
5. Intracerebroventricular injection into conscious rats of the ANG II antagonists [Sar1, Val5, Ala8]ANG II and [NSuc1, Val5, Phg8]ANG II in doses of 1 and 10 μg/kg reduced or abolished the renin-induced increases in blood pressure.
6. The results demonstrate that ANG I as well as ANG II are generated from brain angiotensinogen. The endogenously formed ANG II increases arterial blood pressure. This effect can be inhibited by brain intraventricular administration of specific ANG II antagonists, but it can be increased by inhibition of prostaglandin biosynthesis.
Effect of Isometric Exercise on the Renal Excretion of Sodium and Potassium in Mild Hypertension
Authors: Parfrey P. S. , Wright P. , Ledingham J. M. 
Published: August 2015

1. Basal levels of pulse rate, blood pressure and rates of sodium and potassium excretion were observed in eight white male patients with mild hypertension and eight age-, sex- and colour-matched controls during an initial rest period of 90 min and then for 5 h after a 1 h period of isometric exercise involving all four limbs in rotation. The studies were repeated on another day with the subjects resting instead of exercising for 1 h.
2. Changes in systolic pressure after exercise were similar in the hypertensive and control groups, whereas the rise in diastolic pressure was higher and the rise in pulse rate lower after exercise in the hypertensive group compared with the control group.
3. The changes in the rate of salt excretion were significantly different in the two groups, the hypertensive group retaining proportionately more sodium and potassium over several hours.
Mechanism of the Haemodynamic Interaction between Atenolol, a Cardioselective β-Adrenoreceptor-Blocking Agent, and Chlorthalidone in Hypertensive Patients
Authors: Velasco M. , Guevara J. , Morillo J. , Ramírez A. , Urbina-Quintana A. , Hernández-Pieretti O. 
Published: August 2015

1. The effect of the cardioselective β-adrenoreceptor antagonist atenolol on blood pressure, heart rate, systolic time interval, limb blood flow and limb vascular resistance was studied, both when the drug was used by itself, and also when combined with chlorthalidone. Plasma renin activity and plasma atenolol concentration were also measured.
2. After the administration of atenolol alone, there was a decrease in mean blood pressure from 131·8 ± sem 2·88 mmHg to 119·0 ± 4·05 mmHg (P &lt; 0·001), in heart rate from 76·4 ± 3·58 beats/min to 57·0 ± 2·55 beats/min (P &lt; 0·001), in calf blood flow from 9·23 ± 1·39 ml min−1100 g−1 to 5·05 ± 0·89 ml min−1 100 g−1 (P &lt; 0·001), and an increase in calf vascular resistance from 16·54 ± 1·90 (mmHg min−1100 g−1)/ml to 28·53 ± 3·40 (mmHg min−1 100 g−1)/ml) (P &lt; 0·005). Atenolol did not alter the pre-ejection period index significantly (P &gt; 0·1). In atenolol-treated patients, upon addition of chlorthalidone there was a further decrease in mean blood pressure from 119·0 ± 4·05 mmHg to 105·9 ± 4·12 mmHg (P &lt; 0·001). There was no further significant alteration in heart rate, pre-ejection period index, calf blood flow or calf vascular resistance.
3. Atenolol decreased plasma renin activity from 4·69 ± 0·87 to 2·85 ± 0·68 ng h−1 ml−1 (P &lt; 0·05), and the addition of chlorthalidone increased it from 2·85 ± 0·68 to 3·81 ± 0·98 ng h−1 ml−1 (P &lt; 0·05).
4. There was a 7·8 fold-interindividual variability in the relationship between plasma atenolol concentration and the dose of atenolol after a single oral dose of 100 mg of the drug.
An Evaluation of Tienilic Acid, a New Diuretic Uricosuric Agent, in the Therapy of Arterial Hypertension
Authors: Lechi A. , Covi G. , Danti G. , Riva A. Dalla , Pedrolli E. , Pomari S. 
Published: August 2015

1. Tienilic acid and hydrochlorothiazide were evaluated in a double-blind trial in order to investigate their antihypertensive and metabolic effects.
2. After 5 weeks, the decreases in blood pressure and the changes in plasma or serum electrolytes, urea, creatinine, glucose, cholesterol and triglycerides, and in creatinine clearance, did not differ in the two groups of patients.
3. In patients taking tienilic acid a significant decrease in serum uric acid and an increase in urate clearance was observed, whereas in patients receiving hydrochlorothiazide a slight increase in serum uric acid, with no modification of urate clearance, occurred.
4. The diuretic and antihypertensive actions of tienilic acid and hydrochlorothiazide are very similar. The uricosuric/hypouricaemic effect of tienilic acid could assume clinical relevance in long-term therapy of hypertensive patients.
Serum Testosterone Depression Associated with Hypoxia in Respiratory Failure
Authors: Semple P. D'A. , Beastall G. H. , Watson W. S. , Hume R. 
Published: August 2015

1. We have measured serum testosterone and arterial blood gas values in men with chronic obstructive airways disease.
2. Depression of serum testosterone concentrations was found.
3. The degree of testosterone depression was related to the severity of arterial hypoxia.
Creatinine Metabolism in Chronic Renal Failure
Authors: Mitch W. E. , Collier V. U. , Walser M. 
Published: August 2015

1. Creatinine metabolism was studied in nine patients with severe chronic renal failure who were nevertheless in a nearly steady state with respect to their creatinine pool. Labelled creatinine was injected intravenously and the specific radioactivity of creatinine in urine was measured during the ensuing 5–7 days.
2. In each patient, the decline in specific radioactivity with time was a single exponential function after 12 h. The volume of distribution of creatinine averaged 49.1 ± 2.8% body weight. The average rate of creatinine production was 148 μmol day−1 kg−1, which is similar to predicted values for normal subjects of the same age, weight and sex. Creatinine metabolism rate/kg body weight, estimated as the difference between production rate/kg body weight, determined radioisotopically, and creatinine appearance rate (excretion plus accumulation), averaged 42 μmol day−1 kg−1.
3. Total creatinine metabolism rate/kg body weight was correlated with serum creatinine. Thus, as serum creatinine rises, an increasing fraction of the produced creatinine was metabolized rather than excreted. This relationship could account for the diminished creatinine excretion commonly seen in patients with chronic renal failure.
4. Extrarenal clearance (metabolism/serum creatinine) of this magnitude (approximately 31% of renal clearance in these patients) would be an undetectably small fraction of normal renal clearance. This could explain the absence of demonstrable creatinine metabolism in normal subjects.
5. Two pathways of metabolism were identified: a recycling of creatinine to creatine and an irreversible degradation of creatinine to products other than creatine.
Parathyroid Hormone- and Deoxycorticosterone Acetate-Induced Hypertension in the Rat
Authors: Berthelot A. , Gairard A. 
Published: August 2015

1. Hypertension induced by treatment with deoxycorticosterone acetate and sodium chloride was studied in male Sprague-Dawley rats and related to parathyroid hormone secretion.
2. Lack of parathyroid hormone (due to parathyroidectomy) or decreased parathormone secretion (due to a high-calcium diet) partially inhibited the development of arterial hypertension.
3. In contrast, in thyroparathyroidectomized rats supplemented with thyroxine, the administration of parathyroid hormone rapidly elevated arterial blood pressure.
4. Maintaining a physiological concentration of serum calcium in the absence of parathyroid hormone (by feeding a high-calcium diet to parathyroidectomized rats) was not sufficient to establish mineralocorticoid hypertension.
5. These results show that parathyroid hormone is necessary for the complete development of mineralocorticoid hypertension.
Effect of Phalloidin on Biliary Lipid Secretion in Rats
Authors: Dubin Marta , Erlinger S. 
Published: August 2015

1. The effect of phalloidin on bile acid, phospholipid and cholesterol secretion into bile was studied in rats with bile fistulae.
2. Phalloidin, when given for 7 days, induced a significant decrease in biliary cholesterol concentration and cholesterol saturation index. Bile acid and phospholipid concentration in bile remained unchanged. This effect was less marked in animals receiving the drug for 3 days, and not detectable in animals treated for 1 day.
3. These results provide circumstantial evidence for the hypothesis that microfilament dysfunction may lead to alterations in cholesterol secretion into bile.
Metabolic Aspects of Hypothermia in the Elderly
Authors: Stoner H. B. , Frayn K. N. , Little R. A. , Threlfall C. J. , Yates D. W. , Barton R. N. , Heath D. F. 
Published: August 2015

1. Plasma concentrations of glucose, lactate, amino acids, non-esterified fatty acids, glycerol, ketone bodies, insulin and cortisol were measured in 43 elderly patients with hypothermia. In 15 of these patients forearm arteriovenous differences were also measured. Core temperatures ranged from 25.9 to 35.5°C.
2. The metabolic state was of mobilization of glycogen and triacylglycerol stores, with high plasma concentrations of lactate and lipid metabolites. The plasma concentration of glucose was raised in those with hypothermia of a short duration (&lt;6 h). In other patients it was low in those with core temperatures around 30°C, but below this temperature it was variable and often high. Concentrations of other metabolites or hormones were not related to core temperature.
3. Plasma concentrations of cortisol were high and positively correlated with those of lactate and glycerol, suggesting active involvement in stimulation of muscle glycogenolysis and of lipolysis.
4. Plasma concentrations of insulin ranged from very low to very high and appeared to depend on the concentrations of both glucose and alanine.
5. Arteriovenous differences were generally small. There was peripheral release of lactate and of amino acids but no overall peripheral uptake of glucose. In nine out of 15 patients there was a significant peripheral release of glucose.
6. No differences in metabolism were observed between patients where the hypothermia appeared accidental and those with an obvious precipitating illness, despite a significantly lower mortality in the former group.
7. It was concluded that therapy should primarily involve rewarming of patients by physical means, without metabolic intervention.
Plasma Renin Activity in Normal Human Pregnancy and in Pregnancy-Associated Hypertension, with Reference to Cryoactivation
Authors: Gallery E. D. M. , Stokes G. S. , Györy A. Z. , Rowe J. , Williams J. 
Published: August 2015

1. Because hypertension is the central feature of pre-eclampsia, and because plasma renin activity is known to be elevated in normal pregnancy (with conflicting results published for pre-eclampsia), a prospective study of plasma renin activity was conducted in pregnancy, under conditions of a fixed sodium intake, in 178 initially normotensive volunteer subjects. Thirty of these women developed pregnancy-associated hypertension (pre-eclampsia) in the third trimester.
2. There was a significant elevation of plasma renin activity from the published values for non-pregnant women, throughout gestation in normotensive women. There was no significant difference, at any stage of gestation, between the values for normal women and those who developed pregnancy-associated hypertension.
3. The extent of cryoactivation of renin, produced by usual collection procedures, was investigated in a subgroup of the total population. It was highly significant and quite variable, but was similar in those who developed pregnancy-associated hypertension and in normal pregnant women. The mean increase in plasma renin concentration in maximally cryoactivated samples was 16-fold.
4. Neither measurement of peripheral plasma renin activity nor of cryoactivatable plasma renin concentration is of value in distinguishing between normal pregnant women and those destined for, or with pregnancy-associated, hypertension.
Changes in Lung Volume, Perfusion, Ventilation and Airway Diameter in Dogs with Pulmonary Oedema
Authors: Snashall P. D. , Keyes S. J. , Morgan B. , Rawbone R. G. , McAnulty R. , Mitchell-Heggs P. 
Published: August 2015

1. In dogs that were supported in the upright position and that were breathing spontaneously acute pulmonary oedema was induced either by extracellular fluid volume expansion (n = 5) or by increasing pulmonary microvascular permeability with alloxan (n = 5).
2. Before oedema was induced, the bronchi of the right lung were outlined with tantalum powder.
3. During a baseline period, standard chest radiographs were taken at inflation pressures from 0 to 2 kPa and the distributions of perfusion (with radioactive microspheres) and ventilation (with 133Xe) were measured. Arterial and mixed venous blood samples were taken to estimate the degree of venous admixture (physiological shunt) and pulmonary arterial and wedge pressures were measured.
4. After oedema had developed the radiographs and observations were repeated at a time when the pulmonary vascular pressures were insignificantly different from the baseline state.
5. With induction of oedema, particularly when due to volume expansion, the lower-lung zones decrease in volume. There were no significant changes in the upper zones.
6. Abnormal venous admixture occurred only in dogs with &gt;20% loss of lower-zone volume; volume loss and physiological shunt were significantly correlated.
7. The distribution of perfusion changed little with induction of oedema. Volume-expanded dogs showed a slight diversion of perfusion away from the bases and towards the upper zones.
8. There was an approximately 30% reduction of ventilation to the lung bases and a corresponding increase to the upper zones.
9. With induction of oedema, bronchi were narrowed when there was a reduction of lung volume. There was a significant linear correlation between volume change and narrowing.
The Relationship between the Production of Thromboxane B2 and Malondialdehyde by Human Blood Platelets
Authors: Best L. C. , Jones P. B. B. , Russell R. G. G. 
Published: August 2015

1. The formation of thromboxane B2 and malondialdehyde was studied in human platelet-rich plasma, in gel-filtered platelets and in bovine platelet microsomes.
2. Exogenous sodium arachidonate was converted into thromboxane B2 and malondialdehyde in a concentration-dependent manner. Pre-incubation of platelets with aspirin inhibited the production of both thromboxane B2 and malondialdehyde, although malondialdehyde could apparently be detected in the absence of thromboxane B2.
3. The aggregating agents, thrombin, collagen and the ionophore A23187 also caused production of thromboxane B2 and malondialdehyde. ADP and adrenaline produced a smaller rise whilst the endoperoxide analogue U 46619 had only a slight influence on thromboxane and malondialdehyde, even though they all induced aggregation.
4. Pre-incubation of platelets with imidazole or 1-N-butylimidazole, which inhibit thromboxane synthetase, resulted in an inhibition of both thromboxane B2 and malondialdehyde formation in response to collagen.
5. The results indicate that thromboxane B2 and malondialdehyde are formed in parallel, in comparable quantities. However, under the conditions used in these studies, the apparent amounts of malondialdehyde exceed those of thromboxane B2, especially in the presence of exogenous arachidonate. Thus the thiobarbiturate reaction used to assay malondialdehyde may detect other products of lipid peroxidation.
6. Platelet thromboxane B2 concentrations did not always relate to the extent of aggregation. In particular, platelet aggregation could occur in the absence of detectable thromboxane B2 production.
Conventional Haemodialysis and Ultrafiltration: Effects on Erythrocyte 2,3-Diphosphoglycerate and Oxygen Affinity in Patients with Uraemia
Authors: Severini G. , Giuliani A. , Maffi D. , Cerulli N. 
Published: August 2015

1. The relationship between erythrocyte 2,3-diphosphoglycerate (2,3-DPG) and changes in blood pH and in oxygen affinity were studied in six patients treated with two dialysis techniques: conventional haemodialysis and ultrafiltration followed by conventional haemodialysis.
2. The decrease in erythrocyte 2,3-diphosphoglycerate and increase in pH after conventional haemodialysis may significantly increase the affinity of haemoglobin for oxygen and consequently result in inadequate oxygenation of tissue.
3. Ultrafiltration followed by conventional haemodialysis, on the contrary, is more beneficial for oxygenation of tissue and post-dialysis symptoms may be reduced.
The Effect of Age on the Pharmacokinetics of Diazepam
Authors: MacKlon A. F. , Barton M. , James O. , Rawlins M. D. 
Published: August 2015

1. After intravenous administration to 19 subjects, aged 18–95 years, plasma diazepam concentrations were measured over 160 h. Plasma protein binding of diazepam was also measured in each subject.
2. The terminal plasma half-life of diazepam ranged from 15.0 to 125 h and was positively correlated with age (r = 0.797). Total plasma diazepam clearance was not correlated with age (r = −0.017).
3. The free fraction of diazepam ranged from 0.0137 to 0.0386 and was significantly correlated with age (r = +0.863). Free diazepam clearance, which ranged from 432 to 1870 ml/min, was also correlated with age (r = −0.717).
4. It is concluded that the increased sensitivity of the elderly to diazepam is, at least in part, due to pharmacokinetic factors.
Altered Blood Pressure and Renin Responses to Converting Enzyme Inhibition after Aprotinin-Induced Kallikrein-Kinin-System Blockade
Authors: Overlack A. , Stumpe K. O. , Kuhnert M. , Heck I. 
Published: August 2015

1. The effect of aprotinin-induced blockade of the kallikrein-kinin system on haemodynamic and biochemical responses to converting enzyme inhibition by SQ 14 225 was evaluated in 26 patients with essential hypertension.
2. SQ 14 225 lowered blood pressure in high, normal and low renin hypertension. In low and normal renin patients, but not in high renin patients, the acute blood pressure-lowering effect of SQ 14 225 could be overcome by aprotinin. Aprotinin infusion produced small vasopressor effects in all groups of patients.
3. Aprotinin lowered the level of circulating active renin but not that of inactive renin.
4. It is concluded that in low and normal, but not in high, renin hypertensive patients activation of the kallikrein-kinin system is responsible for the acute blood pressure reduction observed with converting enzyme inhibition.
5. With long-term converting enzyme inhibition kallikrein-kinin system activation seems to play only a minor role.
6. The kallikrein-kinin system may be involved in the regulation of blood pressure.
7. There is no direct evidence of a participation of kallikrein in the activation of prorenin in vivo.
Role of Prostaglandin in the Antihypertensive Mechanism of Captopril in Low Renin Hypertension
Authors: Abe Keishi , Ito Toru , Sato Makito , Haruyama Toshiaki , Sato KO , Omata Ken , Hiwatari Masao , Sakurai Yutaka , Imai Yutaka , Yoshinaga Kaoru 
Published: August 2015

1. The role of endogenous prostaglandins in the antihypertensive mechanism of the angiotensin converting enzyme inhibitor, captopril, was investigated.
2. An unequivocal reduction in blood pressure and significant increase in plasma renin activity and urinary prostaglandin E excretion were found after the captopril administration.
3. The changes in blood pressure, plasma renin activity and urinary prostaglandin E excretion induced by captopril were reversed after the inhibition of endogenous prostaglandin synthesis by indomethacin. However, the responses in low renin hypertension were different from those in normal renin hypertension.
4. In low renin hypertensive patients who responded to captopril, the hypotensive effect was abolished after the addition of indomethacin, whereas no marked change in blood pressure was induced by indomethacin in normal renin hypertensive patients. In contrast, plasma renin activity was markedly increased after captopril administration in normal renin hypertension, and no significant change was found in low renin hypertension.
5. Potentiation of the prostaglandin system seems to be a principal factor in the antihypertensive mechanism of captopril in low renin hypertension, and inhibition of the renin-angiotensin system is important in normal renin hypertensives.
6. The increase in renin release after the administration of captopril was inhibited by indomethacin, suggesting that an endogenous prostaglandin system may contribute to the short feedback mechanism of renin release.
Cyclic AMP Generation in Hypothalamus of Hypertension-Prone and -Resistant Rats
Authors: Kobrin I. , Ebstein R. , Ben-Ishay D. 
Published: August 2015

1. The noradrenaline-induced accumulation of cyclic AMP is decreased in both the anterior and the posterior hypothalamus of hypertension-prone as compared with resistant rats, but is similar in the cortex.
2. The nonadrenaline-induced accumulation of cyclic AMP is decreased in the posterior hypothalamus as compared with the anterior hypothalamus of both strains.
3. The decreased sensitivity to phosphodiesterase inhibitor in the hypothalamus of hypertension-prone as compared with resistant rats suggests that strain differences in phosphodiesterase activity may exist.
4. Since differences in cyclic AMP were found in the hypothalamus and the medulla oblongata, regions involved in blood pressure control, but not in the cortex, they may be relevant to the diverse susceptibility to hypertension of hypertension-prone and resistant rats.
Systemic and Regional Haemodynamics in Anterior Hypothalamic Hypertension in Spontaneously Hypertensive and Wistar-Kyoto Rats
Authors: Suarez D. H. , Pegram Barbara L. , Frohlich E. D. 
Published: August 2015

1. Systemic and regional haemodynamics were determined in conscious Wistar-Kyoto and spontaneously hypertensive rats with the radioactive microsphere technique after sham lesion or bilateral electrolytic lesion of the nuclei of the anterior hypothalamus.
2. Anterior hypothalamic lesions produced an increase in blood pressure, heart rate and cardiac output.
3. In the rats with lesions there were changes in regional haemodynamics: heart and skeletal muscle flow increased; renal, skin and splanchnic flow decreased.
4. The haemodynamic consequences of ablation of the anterior hypothalamus were similar in both normotensive Wistar-Kyoto and spontaneously hypertensive rats. The haemodynamic pattern resembles that seen during fighting and exercise.