bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of Urine-Concentrating Ability in Man: Effect of Fludrocortisone and Urea in Enhancing Response to Vasopressin
Authors: Goonaratna C. de F. W. , Wrong O. M. 
Published: August 2015

1. Healthy subjects, given a long-acting preparation of vasopressin intramuscularly, excreted a significantly less concentrated urine than when subjected to fluid deprivation for 28 h.
2. When fludrocortisone, a potent mineralocorticoid, was given in addition to vasopressin the urine was not significantly less concentrated than after fluid deprivation.
3. Oral urea-loading also enhanced the urine-concentrating power of vasopressin but its effect was less marked than that of fludrocortisone. Oral urea did not increase further the urine concentration achieved by combined fludrocortisone and vasopressin.
4. Renal concentrating power was assessed in fourteen patients with renal disease and impaired concentrating ability. Fludrocortisone significantly enhanced the urine concentration achieved by vasopressin alone and the resultant urine was not significantly less concentrated than that achieved by fluid deprivation.
5. The action of fludrocortisone in enhancing the urine-concentrating effect of vasopressin is similar to that of aldosterone and is probably due to the increased sequestration of solute in the renal medulla, caused by increased reabsorption of sodium chloride in the ascending limb of the loop of Henle.
6. In the clinical assessment of renal concentrating power, the combined use of fludrocortisone and vasopressin has potential advantages over established methods.
Effect of Bile-Duct Ligation on Organelle Marker Enzymes in the Liver and Serum of Rats
Authors: Peters T. J. , Neale G. , Heath J. R. 
Published: August 2015

1. Marker enzymes for the principal subcellular organelles of rat liver were asayed in the liver of rats 1 day and 8 days after bile-duct ligation or after laparotomy as a control procedure.
2. The microsomal enzymes in liver tissue showed complex changes. Benz[α]pyrene hydroxylase activity, predominantly found in the smooth endoplasmic reticulum, was decreased. Glucose 6-phosphatase activity and ribonucleic acid, which are localized predominantly in the rough endoplasmic reticulum, were increased.
3. The plasma membrane enzyme, alkaline phosphatase, increased in activity after bile-duct ligation.
4. No changes in mitochondrial enzyme activities were noted after 1 day but there was a 50% reduction 8 days after ligation. Lysosomal enzyme activities did not change in the liver tissue.
5. Liver catalase and d-amino acid oxidase activities showed a slight increase at 1 day post-ligation but a significant fall by 8 days.
6. Lactate dehydrogenase, a cytosol enzyme, showed a decrease in activity after 1 day but an increase in tissue activities 8 days after ligation.
7. Serum activities of mitochondrial, plasma membrane, microsomal, lysosomal and cytosol marker enzymes tended to increase post-ligation, particularly at 8 days.
8. Monoamine oxidase, a predominantly mitochondrial enzyme, was greatly elevated in the serum after 1 day but had returned to normal activities by 8 days.
Postural Fluid Retention in Patients with Idiopathic Oedema: Lack of Relationship to the Phase of the Menstrual Cycle
Authors: Edwards O. M. , Bayliss R. I. S. 
Published: August 2015

1. Water and electrolyte excretion was measured in the follicular and luteal phases of the menstrual cycle in seven patients with idiopathic oedema and in four post-menopausal patients with this condition.
2. In contrast to previous findings in healthy women, the reduction in urinary flow and sodium excretion on being tilted to the upright position was not significantly different in the follicular and luteal phases in pre-menopausal patients and there were no significant differences between pre- and post-menopausal patients.
3. The percentage increase in packed cell volume on standing was significantly greater in patients with idiopathic oedema than in normal subjects in the luteal phase of the menstrual cycle.
4. It is postulated that the enhanced retention of electrolytes and water in response to tilting in patients with idiopathic oedema is a compensatory mechanism for the decreased effective blood volume at that time.
Effect of Immunization against Angiotensin II on Blood Pressure and on Plasma Aldosterone in the Rabbit
Authors: Beckerhoff R. , Kappeler M. , Vetter W. , Armbruster H. , Siegenthaler W. 
Published: August 2015

1. Rabbits were actively immunized against angiotensin II (AII).
2. Basal plasma aldosterone concentration was 0.058 ±0.027 pmol/ml (20.7±9.6 pg/ml) (mean±SD) in immunized and 0.056±0.021 pmol/ml (20.2±7.5 pg/ml) in control animals during suppression of adrenocorticotrophic hormone by dexamethasone. When the endogenous formation of AII was stimulated by frusemide, by haemorrhage or by feeding with low sodium diet, a significant increase of plasma aldosterone was observed with no difference between immunized and non-immunized animals.
3. In non-immune rabbits, the average mean arterial blood pressure rose 13 mmHg during the infusion of AII (5 pmol min−1 kg−1) and 27 mmHg during the infusion of 50 pmol min−1 kg−1. In contrast, there was no clear increase in blood pressure in the immunized animals. The blood pressure rose in immune animals (15 mmHg) and in non-immune animals (36 mmHg) during the infusion of 200 pmol min−1 kg−1 AII. Plasma aldosterone rose in all animals in response to each of the three infusions with no significant difference between the two groups.
4. It is concluded that the immunization against AII blocked only the pressor effect of the peptide but had no clear influence on the response of plasma aldosterone to increased AII. Differences between the affinities of the adrenal and vascular AII receptors may explain these findings.
The Pressor Role of Angiotensin in Salt Deprivation and Renal Hypertension in Rats
Authors: Coleman T. G. , Guyton A. C. 
Published: August 2015

1. Angiotensin may influence arterial pressure either by direct vasoconstriction or by more slowly developing effects on thirst and renal function. The importance of direct vasoconstriction was estimated in rats during salt deprivation and renal hypertension by observing the fall in blood pressure that immediately followed injection of converting-enzyme inhibitor.
2. Chronically salt-deprived rats had normal arterial pressure, cardiac output and total peripheral resistance before inhibition. However, inhibiting the formation of angiotensin II caused marked decreases in arterial pressure (−47 mmHg) and total peripheral resistance (−30%).
3. Animals made hypertensive by renal artery constriction showed large decreases in arterial pressure when angiotensin formation was inhibited only during the first few days after constriction. In the chronic, benign phase of hypertension, animals with both clamp plus contralateral nephrectomy and with unilateral clamp only, showed decreases in pressure after inhibition (−12 to 16 mmHg) that were only slightly greater than decreases observed in normotensive control animals.
4. These results indicate that total peripheral resistance and the activity of the renin-angiotensin system can change separately. In salt deprivation, even though an increased fraction of resistance was due to angiotensin, total peripheral resistance was normal. In chronic renal hypertension, total resistance was undoubtedly elevated, but only partially because of the vasoconstrictor effect of angiotensin.
Secretion of Inorganic Phosphate in the Rat Nephron
Authors: Boudry J.-F. , Troehler U. , Touabi M. , Fleisch H. , Bonjour J.-P. 
Published: August 2015

1. The existence of tubular secretion of inorganic phosphate (Pi) in the mammalian kidney has been investigated by studying the renal response of rats infused with sodium phosphate by three different techniques.
2. Clearance studies indicate that, in anaesthetized rats, the net tubular reabsorption decreases markedly in response to Pi infusion. In conscious rats, the clearance of Pi slightly exceeded that of inulin at high plasma Pi concentration.
3. Free-flow micropuncture in control rats showed a net tubular reabsorption of Pi along the proximal tubule, and probably between the end of the distal tubule and the ureteral urine. In phosphate-loaded rats, whether receiving parathyroid hormone or not, an apparent net secretion of Pi was observed between the end of the distal tubule and the ureteral urine. In the phosphate-loaded group receiving parathyroid hormone, net secretion was also observed very early in the proximal tubule followed by a predominant reabsorption along this segment. Thus the early proximal tubule and probably also the terminal nephron can be the site of either net reabsorption or net secretion.
4. Microperfusions of proximal tubules show a fall in the specific radioactivity of the perfused radioactive Pi solution, indicating entry of Pi into the lumen.
Methionine Adenosyltransferase, Cystathionine β-Synthase and Cystathionine γ-Iyase Activity of Rat Liver Subcellular Particles, Human Blood Cells and Mixed White Cells from Rat Bone Marrow
Authors: Allsop Jennifer , Watts R. W. E. 
Published: August 2015

1. Methionine adenosyltransferase (ATP:l-methionine-S-adenosyl transferase, EC 2.5.1.6), cystathionine β-synthase [l-serine hydro-lyase (adding homocysteine), EC 4.2.1.22] and cystathionine γ-lyase [l-cystathionine cysteine-lyase (deaminating), EC 4.4.1.1] activities were found only in the cytosol fraction of rat liver cells. None was found in the mitochondrial or endoplasmic reticulum fractions as judged by the distribution of marker enzymes on a density gradient after centrifugation of the cytoplasmic fraction of a liver homogenate, or in a preparation of liver cell nuclei.
2. Polymorphs, lymphocytes (with admixed monocytes) and mixed bone marrow white cells contained no methionine adenosyl transferase, cystathionine β-synthase or cystathionine γ-lyase activities.
3. The possible bearing of these results on the problem of abnormal cystine storage in cystinosis is briefly discussed.
Changes in Protein-Bound Calcium in the Serum of Haemodialysis Patients
Authors: Gosling P. , Robinson B. H. B. , Sammons H. G. 
Published: August 2015

1. Ionized calcium, protein-bound calcium and total calcium in serum were measured in patients receiving haemodialysis treatment.
2. During dialysis, the ionized calcium fraction decreased and the bound calcium increased. The blood pH also increased.
3. Studies in vitro suggested that the fall in ionized calcium and rise in protein-bound calcium were larger than could be explained by the redistribution of calcium fractions due to the pH change.
4. An explanation could be that haemodialysis increases calcium binding by serum proteins. Such an effect may be implicated in the aetiology of hyperparathyroidism and bone disease in patients undergoing haemodialysis.
A Comparison of Propranolol and Compound R03-4787 in the Treatment of Arterial Hypertension in Man
Authors: George C. F. , Lewis P. J. , Steiner J. A. , Dollery C. T. 
Published: August 2015

1. The effects of propranolol and R03-4787, a new beta-adrenoceptor antagonist with a partial agonist activity, have been studied in a blind, cross-over comparison with placebo.
2. In ten patients who completed the study, the two drugs produced a similar reduction in blood pressure; the reduction in heart rate with propranolol was significantly(P0.001)greater than that produced by R03-4787.
3. Plasma renin activity averaged 4.13 ± 1.37 ng h−1ml−1 on placebo, fell to 3.64 ± 1.47 ng h−1ml−1 on propranolol and to 2.50 ± 1.39 ngh−1ml−1 on R03-4787.
4. No correlation was demonstrable between the log plasma concentration of either propranolol or R03-4787 and change in blood pressure.
Changes in Plasma Renin Activity and Blood Pressure after Acute and Chronic Administration of β-Adrenergic Receptor-Blocking Drugs
Authors: Morgan T. , Carney S. , Roberts R. 
Published: August 2015

1. Prindolol and propranolol chronically cause a fall in mean blood pressure and mean plasma renin activity, but no correlation was observed between the two variables.
2. The response of blood pressure to prindolol and propranolol was not predicted by the basal plasma renin activity.
3. Propranolol administered acutely caused the plasma renin activity to fall with no acute change in blood pressure, whereas prindolol caused the blood pressure to fall with no change in plasma renin activity.
4. The effects of β-adrenergic-blocking drugs on plasma renin activity and blood pressure can be dissociated and it is unlikely that their hypotensive action is mediated through the renin-angiotensin system.
5. Basal plasma renin activity does not identify the patients who will respond to β-adrenergic-blocking drugs.
Some Haemodynamic Effects of Compound AH 5158 Compared with Propranolol, Propranolol plus Hydrallazine, and Diazoxide: The Use of AH 5158 in the Treatment of Hypertension
Authors: Prichard B. N. C. , Thompson F. O. , Boakes A. J. , Joekes A. M. 
Published: August 2015

1. Intravenous administration of compound AH 5158, which possesses alpha- and beta-adrenergic receptor-blocking properties, produces haemodynamic effects similar to those seen from the combined effects of propranolol and hydrallazine.
2. Chronic oral administration has demonstrated that compound AH 5158 is an effective hypotensive agent capable of controlling the blood pressure in patients previously requiring large doses of drugs such as methyldopa. Some postural and exercise hypotension may be seen with larger doses.
Plasma Renin Activity and Cardiovascular Disease
Authors: Hickler R. B. , Lauler D. P. , Gleason R. E. , Christlieb R. 
Published: August 2015

1. A group of patients with essential hypertension was divided into three categories on the basis of the plasma renin activity.
2. There was no correlation between the plasma renin activity categorized as high, normal or low and the duration of hypertension, the incidence of left ventricular enlargement, the blood urea nitrogen, serum creatinine, cholesterol or uric acid respectively.
3. Analysis of data showed that the incidence of cardiovascular events in the hypertensive population correlated with the plasma renin activity only in combination with known risk factors.
Technique for Rapid Control of Hypertension with Oral Minoxidil
Authors: O'Malley K. , McNay J. L. 
Published: August 2015

1. Twelve patients with essential hypertension were treated aggressively with minoxidil in order to achieve blood pressure control as rapidly as possible.
2. After an initial dose of 5 mg, dose increments were administered 6 hourly until a fall in blood pressure was observed.
3. The size of additional doses was determined by the magnitude of and response to the lowest effective dose and the therapeutic objective.
4. Over a time-interval of 24–42 h blood pressure was reduced to normal or near normal in each case.
5. Analysis of the relationship between blood pressure response and cumulative dose indicates that at sub-optimum blood pressure responses it is safe and efficacious to give half the antecedent cumulative dose as a single dose in arriving at the therapeutic objective.
Central Sympathetic Transmitters and Hypertension
Authors: Henning M. 
Published: August 2015

1. The aim of this presentation has been to review the current status of some central neurotransmitter mechanisms in the control of arterial blood pressure and in experimental hypertension. In addition, anti-hypertensive drugs with centrally mediated actions have been considered.
2. There is ample evidence for a role of central noradrenaline mechanisms in central cardiovascular regulation. The catecholamine precursor, l-3,4-dihydroxyphenylalanine, lowers blood pressure by activating sympatho-inhibitory noradrenergic mechanisms in the lower brain stem. The receptors mediating this effect conform to the α-adrenergic type in peripheral tissues. Central noradrenaline receptors also appear to influence blood pressure at suprabulbar levels in the brain. Evidence is accumulating that central adrenergic receptors of the β type are also implicated in cardiovascular control. Central dopamine, 5-hydroxytryptamine and acetylcholine neurons are possibly involved in circulatory regulation but their precise role is less clear at present.
3. Considerable work has been done attempting to relate alterations in central neurotransmitter function to arterial hypertension. Central noradrenaline neurons appear to participate in the origin and maintenance of neurogenic hypertension. This may also be the case for other types of experimental hypertension but the results are less conclusive.
4. Anti-hypertensive drugs may act by interfering with central neurotransmitter function. The action of l-α-methyl-3,4-dihydroxyphenylalanine (methyldopa) is largely mediated through an activation by its metabolite, methylnoradrenaline, of noradrenaline mechanisms in the lower brain stem. The central noradrenaline agonist, clonidine, probably acts in an analogous way although some evidence indicates that this drug may influence blood pressure at several levels of central cardiovascular control.
Spinal Sympathetic Reflexes in the Cat and the Pathogenesis of Arterial Hypertension
Authors: Malliani A. , Lombardi F. , Pagani M. , Recordati G. , Schwartz P. J. 
Published: August 2015

1. In vagotomized anaesthetized cats with both common carotid arteries occluded, stretch of the thoracic aorta induced reflex increases in arterial blood pressure, heart rate and left ventricular dP/dtmax.. Similar responses were obtained in cats with spinal transection at the level of the first cervical nerve roots.
2. The hypothesis is advanced that sympathetic excitatory reflexes may contribute to the maintenance of hypertension through positive feedback.
Electrical and Dynamic Responses of the Human Hyperkinetic Heart to Sympathetic Stimuli
Authors: Bartorelli C. , Polese A. , Fiorentini C. , Magrini F. , Olivari M. T. , Guazzi M. 
Published: August 2015

1. The elevated beta-receptor responsiveness to adrenergic stimuli makes subjects with the primary hyperkinetic cardiac syndrome ideal for studying the electrical and dynamic responses of the heart to sympathetic activation.
2. In twelve men presenting with the syndrome, the effects of mental arithmetic and painful (cold) stress on the cardiac inotropic state were tested and correlated with the concomitant electrocardiographic changes.
3. Arithmetic and cold evoked responses opposite and divergent from the base-line state: The former induced vasodilatation, enhancement of cardiac rate, output, contractility and deep T wave inversion; the latter caused vasoconstriction, cardiac depression and full restoration of repolarization.
4. The sympathetic outflow elicited by stress is not generalized, but selectively directed to different circulatory levels in relation to the stimulus at work; cardiac sympathetic stimulation or inhibition has opposite effects on the repolarization phase.
Differential Effect of Prostaglandin A1 in Hypertensive Patients with Low, Normal and High Renin
Authors: Krakoff L. R. , Vlachakis N. , Mendlowitz M. , Stricker J. 
Published: August 2015

1. Eighteen hypertensive in-patients were studied during a period of controlled electrolyte intake and, on the basis of determinations of mid-day plasma renin activity (PRA), were classified into low, normal and high renin sub-groups.
2. The responses of systemic arterial pressure, urine sodium excretion rate and PRA to infusion of prostaglandin A1 (PGA1) at a rate of 0.4 μg min−1 kg−1 for 60 min differed among the renin sub-groups.
3. The low renin sub-group displayed the greatest fall in arterial pressure and the greatest increase in sodium excretion rate during infusion of PGA1; PRA was unaffected. The normal renin group demonstrated a lesser reduction of arterial pressure and lesser rise in sodium excretion rate during infusion of PGA1 compared with the low renin group; PRA rose significantly during infusion of PGA1. No significant change in arterial pressure occurred in the high renin group during infusion of PGA1; sodium excretion rate rose less than that observed in the other two groups. Infusion of PGA1 caused striking increases in PRA in the high renin group.
4. The changes in PRA during infusion of PGA1 may explain the differences in arterial pressure and sodium excretion rate observed in the three renin sub-groups. The results also suggest that the role of the vasodilating prostaglandins may differ in the pathogenesis of low, normal and high renin hypertension.
Micromethods for the Simultaneous Measurement of Intracellular Potassium and Corticosterone Output of Isolated Adrenal Cortical Cells
Authors: Mendelsohn F. A. O. , Warren R. L. 
Published: August 2015

1. A technique is described for the measurement of potassium and water spaces in less than 1 μ1 of packed cells.
2. The total potassium content of cell pellets is measured in a perchloric and nitric acid extract by flame spectrophotometry. The potassium in trapped medium is estimated from the distribution space of hydroxy[14C]methylinulin and subtracted from the total potassium content to give intracellular potassium content. Corticosterone output was measured by radioimmunoassay.
3. The simultaneous measurement of total water from the [3H]water space allows calculation of the intracellular water space.
4. Values obtained for intracellular potassium content, intracellular water space and calculated intracellular potassium concentration are presented for different preparations of isolated adrenal cortical cells.
Effect of Ethanol on the Ventilatory Responses to Oxygen and Carbon Dioxide in Man
Authors: Sahn S. A. , Lakshminarayan S. , Pierson D. J. , Weil J. V. 
Published: August 2015

1. Hypoxic and hypercapnic ventilatory drives were measured in eight healthy male subjects before and after ingestion of ethanol, in a dose of 17 mmol/kg body weight.
2. A significant decrease in hypoxic ventilatory drive was observed at 20 min after ethanol (P < 0.05). A significant depression in hypercapnic drive was observed at 70 min after ingestion of ethanol (P < 0.05). The mean peak blood ethanol (24 mmol/l) occurred at 20 min, at which time the lowest mean hypoxic drive was recorded.
3. Ethanol in moderate doses produced a depression of both hypoxic and hypercapnic ventilatory drives in normal subjects. This suggests that ethanol may play a role in the precipitation of acute respiratory failure in certain patients in whom the ventilatory drive is already impaired, as in chronic airways obstruction.
Liposomes as Vehicles for the Local Release of Drugs
Authors: Segal A. W. , Gregoriadis G. , Black C. D. V. 
Published: August 2015

1. The rat testicle was used in studying the release of radio-labelled compounds from locally injected liposomes of various sizes, charge and lipid composition.
2. Large unsonicated liposomes markedly delayed the release of entrapped 125I-labelled albumin. Delay was due to liposomal entrapment rather than the presence of lipid per se and it was greater with neutral than charged liposomes. The albumin left the testis after release from, and not in association with, liposomal lipid.
3. Large unsonicated liposomes also delayed the release of entrapped actinomycin D and 5-fluorouracil. The former retained its cytotoxic activity and resulted in focal, dose-dependent tissue necrosis.
4. Small sonicated liposomes did not delay the release of entrapped 125I-labelled albumin, and enhanced release of actinomycin D, producing high concentrations of these compounds, which were released in association with liposomal lipid, in draining lymph nodes.