bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Intrinsic Brain Iso-Renin-Angiotensin System in the Rat: Its Possible Role in Central Mechanisms of Blood Pressure Regulation
Authors: Ganten D. , Hutchinson J. S. , Schelling P. 
Published: August 2015

1. Angiotensin is produced by the intrinsic iso-renin-angiotensin system.
2. Angiotensin is secreted into the cerebrospinal fluid of nephrectomized rats.
3. Angiotensin in cerebrospinal fluid elevates systemic blood pressure.
4. Rats with hereditary diabetes insipidus are virtually non-responsive to intraventricular angiotensin.
5. Angiotensin II is elevated in the cerebrospinal fluid of spontaneously hypertensive rats.
6. An intraventricular perfusion of the angiotensin II receptor-blocking agent P 113 decreases blood pressure in spontaneously hypertensive rats.
Effect of Prostaglandins (E2 and A2) on the Enzymatic Reaction of Human Renin in Isolated Homologous System and with Added Normal and Hypertensive Plasma
Authors: Eggena P. , Barrett J. , Sambhi M. 
Published: August 2015

1. Prostaglandin E2 significantly inhibits the renin reaction in whole plasma as well as in the isolated system of semi-purified human renin and human renin substrate. The inhibitory effect of prostaglandin A2 was less marked in whole plasma and absent in the isolated system.
2. The inhibitory effect of prostaglandin E2 was more marked in normal than hypertensive plasma and was maximal at the lowest concentration used. In hypertensive plasma the maximal inhibitory effect was achieved at tenfold higher concentrations.
3. In normal plasma prostaglandin E2 does not affect the rate of product formation (k5 = k6), but inhibits the overall renin reaction by decreasing the total amount of available enzyme-substrate and enzyme-substrate modifier complex (K2K3).
4. In hypertensive plasma prostaglandin E2 acts as a potential accelerator of the rate of product formation (k6k5). In the range of substrate concentration employed, the apparent inhibitory effect is explained by an even greater lack of available complex (K2K3). This behaviour in hypertensive plasma is consistent with the presence of an additional modifier (? activator).
Renal Kallikrein Content of Spontaneously Hypertensive Rats
Authors: Favaro S. , Baggio B. , Antonello A. , Zen A. , Cannella G. , Todesco S. , Borsatti A. 
Published: August 2015

1. The kallikrein content of kidneys from spontaneously hypertensive and normal rats at birth and at age 37 days was determined.
2. Kallikrein values were significantly lower in the hypertensive rats.
3. It is suggested that the lowered kallikrein may be related to the development of hypertension.
The Actions of Bradykinin and Eledoisin in the Canine Isolated Kidney: Relationships to Prostaglandins
Authors: McGiff J. C. , Itskovitz H. D. , Terragno N. A. 
Published: August 2015

1. The effects of two vasodilator polypeptides, bradykinin and eledoisin, were studied in isolated blood-perfused canine kidneys before and after administration of indomethacin, an inhibitor of prostaglandin synthesis. Bradykinin, but not eledoisin, releases renal prostaglandins.
2. Before administration of indomethacin, bradykinin decreased urinary osmolality and increased free water clearance, whereas eledoisin did not affect the excretion of solute-free water. After administration of indomethacin, the renal vasodilator action of bradykinin was reduced but the vasodilator action of eledoisin was unaffected.
3. Fractional excretion of sodium was not affected by bradykinin before but was increased after administration of indomethacin. Reduction in glomerular filtration rate contributed to changes in sodium excretion produced by bradykinin and eledoisin.
4. The release of prostaglandins from the kidney by bradykinin amplifies the renal vasodilator action of the kinin and possibly mediates its effect on excretion of solute-free water.
Location of Aldosterone-Producing Adenomas by the Determination of Plasma Aldosterone in Adrenal Vein or Renal Vein Blood
Authors: Fukuchi S. , Takenouchi T. , Nakajima K. , Watanabe H. , Sugita A. 
Published: August 2015

1. Aldosterone-producing adenomas were located before operation in eighteen patients by comparison of aldosterone concentrations in blood obtained by percutaneous catheterization of the adrenal vein or renal vein. The concentration of aldosterone in the venous effluent from the adrenal glands containing adenomas was significantly greater than in the venous effluent from contralateral glands.
2. Catheterization of the adrenal vein is, however, technically difficult. The location of adrenal adenomas was also possible by analysis of blood from the renal vein.
3. If the concentrations of aldosterone in blood from the left renal vein were higher than those from the right, the existence of a left adrenal adenoma was suggested. A high value in plasma, obtained from the inferior vena cava above the entry of the right adrenal vein, showed a right adrenal adenoma. This procedure identified very small functional adenomas which could not be demonstrated radio-graphically, or seen or palpated at surgery.
4. It was concluded that differential aldosterone measurement after percutaneous bilateral adrenal vein or renal vein catheterization can be used as a definitive test for the location of an aldosterone-producing adenoma, where this is uncertain.
Pituitary-Adrenal Response to Static Exercise in Man
Authors: Few J. D. , Imms F. J. , Weiner J. S. 
Published: August 2015

1. Changes in plasma concentrations of catecholamines and Cortisol were measured before and after static exercise performed by the subject pushing with both legs against a strain-gauge bar. No marked changes in plasma catecholamine were observed but plasma Cortisol increased after the subject pushed for 3 min at 50% of maximum force.
2. Holding a 20 kg weight for 5 min in one hand caused a rise in plasma Cortisol and in plasma ACTH but no changes in growth hormone were observed.
Studies on the Nature of Complexes Formed by Copper with Human Alimentary Secretions and Their Influence on Copper Absorption in the Rat
Authors: Gollan J. L. 
Published: August 2015

1. Human gastrointestinal secretions formed soluble copper complexes when labelled in vitro with 64Cu.
2. Copper-binding substances of low molecular weight were demonstrated in the saliva, gastric juice and secretin-stimulated duodenal aspirate of normal subjects by dialysis and gel-chromatography studies.
3. The nature of the copper complexes formed by secretions obtained from patients with Wilson's disease was similar to that of complexes formed by secretions of normal subjects.
4. Bile contained a copper-binding fraction of high molecular weight which was more concentrated in gall-bladder than hepatic bile. Between pH 5 and pH 8, this component had a greater binding affinity for copper than the other alimentary secretions or EDTA at a concentration of 10 mmol/l.
5. Absorption of 64Cu from 64Cu-labelled saliva, gastric juice or l-histidine solution (100 mmol/l) administered intraduodenally into groups of rats was similar to that observed in a control series given [64Cu]cupric acetate in sodium chloride solution. In contrast, the absorption of 64Cu from labelled hepatic and gall-bladder bile was significantly reduced.
6. The results suggest that dietary copper forms soluble complexes with the alimentary secretions and that these complexes influence absorption of the metal according to their molecular size. The net uptake of ingested copper from the gut lumen may represent a balance between the influence of dietary chelates, low-molecular-weight ligands in the alimentary secretions and a macromolecular copper-binding complex of bile.
Intrarenal Platelet Consumption in the Diffuse Proliferative Nephritis of Systemic Lupus Erythematosus
Authors: Clark W. F. , Lewis M. L. , Cameron J. S. , Parsons V. 
Published: August 2015

1. Platelet survival and an index of the localization of platelets in the kidney were studied in patients with the proliferative nephritis of systemic lupus erythematosus, either focal or diffuse, and in control subjects. Platelet survival was reduced in patients with proliferative lupus nephritis, more in those with diffuse rather than focal renal involvement.
2. The index of renal platelet localization in patients with diffuse proliferative nephritis suggested an intrarenal platelet consumption not found in other groups.
3. A patient with the classical platelet autoantibody disease, idiopathic thrombocytopenic purpura, also showed reduced platelet survival but localization of platelets was in the spleen rather than the kidney.
4. Intrarenal platelet consumption in diffuse proliferative lupus nephritis may be an epiphenomenon of pre-existing scarring or platelet aggregation secondary to immune complex-formation, which contributes to the progressive sclerosing lesions of this form of nephritis.
Effect of Diazoxide on Renal Handling of Sodium in the Rat
Authors: Fine L. G. , Weber H. 
Published: August 2015

1. To assess whether diazoxide-induced sodium retention is due to a direct renal action of the drug, independent of its systemic haemodynamic effects, diazoxide was infused directly into one renal artery of hydropenic rats. During the infusion period there was a small fall in mean systemic arterial blood pressure. There were no significant changes in the clearances of inulin or p-aminohippurate by either kidney.
2. Absolute and fractional excretion of sodium were unchanged on the non-infused side. On the side of infusion, there was a significant increase in absolute and in fractional sodium excretion.
3. Thus natriuresis rather than sodium retention seems to be the direct renal effect of diazoxide and may be related to its vasodilator properties.
Plasma Catecholamines, Plasma Renin Activity and Plasma Aldosterone in Tetraplegic Man, Horizontal and Tilted
Authors: Mathias C. J. , Christensen N. J. , Corbett J. L. , Frankel H. L. , Goodwins T. J. , Peart W. S. 
Published: August 2015

1. Plasma catecholamines, plasma renin activity, plasma aldosterone and haematocrit were measured in four subjects with physiologically complete cervical spinal cord transections, before, during and after head-up tilt to 45° for 30 min. Plasma catecholamines were measured in five normal male volunteers in the supine position and after head-up tilt to 45° for 10 min.
2. After 10 min of head-up tilt, the plasma noradrenaline rose 14% in the tetraplegic patients and 115% in the control subjects. These findings indicate a failure of sympathetic activity in response to head-up tilt in the tetraplegic patients, probably caused by interruption of pathways by which the brain normally controls sympathetic outflow.
3. In the tetraplegic patients the resting plasma renin activities were above normal, and rose more quickly and greater on head-up tilt than in published studies of normal subjects. It is likely that the renal baroreceptors are important in the control of renin release.
4. In the tetraplegic patients, there was a late rise in plasma aldosterone which was probably due to the elevation in plasma renin activity.
Evidence for Active Transport of Tripeptides by Hamster Jejunum in Vitro
Authors: Addison Jill M. , Burston D. , Payne J. W. , Wilkinson S. , Matthews D. M. 
Published: August 2015

1. This paper describes the uptake by rings of everted hamster jejunum in vitro of three peptides with structural features making them resistant to hydrolysis, glycylsarcosylsarcosine, glycylsarcosylsarcosylsarcosine and β-alanylglycylglycine.
2. Glycylsarcosylsarcosine was taken up by a saturable mechanism and accumulated intact in the intracellular compartment of the intestinal wall, apparently against an electrochemical gradient. Its uptake was reduced by Na+-replacement, anoxia and metabolic inhibitors. It was concluded that uptake of this peptide was the result of Na+-dependent active transport.
3. Glycylsarcosylsarcosylsarcosine was very poorly taken up and its uptake did not appear to be the result of active transport.
4. β-Alanylglycylglycine appeared intact in the intracellular compartment of the intestinal wall on a substantial scale though it was not concentrated. No satisfactory evidence of uptake by a saturable mechanism was obtained. Uptake was, however, inhibited by anoxia, 2,4-dinitrophenol and Na+-replacement. Reasons are given for supposing that uptake of this peptide may be the result of Na+-dependent active transport by the same carrier as that utilized by glycylsarcosylsarcosine.
5. The results suggest that provided that they escape brush-border hydrolysis, tripeptides, like dipeptides, are actively transported into the absorptive cells of the intestinal mucosa, but that the ability of these cells to take up peptides by an active mechanism is unlikely to extend to tetrapeptides.
Effect of Intravenous Frusemide on Plasma Renin Concentration: Suppression of Response in Hypertension
Authors: Padfield P. L. , Allison M. E. M. , Brown J. J. , Lever A. F. , Luke R. G. , Robertson C. C. , Robertson J. I. S. , Tree M. 
Published: August 2015

1. Intravenous frusemide produced in normal subjects a prompt rise of plasma renin concentration which correlated with urinary sodium.
2. The renin response to frusemide was suppressed in patients with primary hyperaldosteronism.
3. In patients with low-renin hypertension and normal renin essential hypertension, the renin response to frusemide was similarly suppressed.
4. Suppression of the renin response to frusemide is therefore a feature of hypertension not confined to patients with primary hyperaldosteronism and low-renin hypertension.
5. Thus low-renin hypertension does not appear to constitute a distinct diagnostic entity.
6. It is suggested that suppression of the renin response is part of a long-term renal adaptation to high blood pressure.
The Effect of External Potassium Concentration on Leucocyte Cation Transport in Vitro
Authors: Hilton P. J. , Edmondson R. P. S. , Thomas R. D. , Patrick J. 
Published: August 2015

1. Sodium and potassium transport rates in human leucocytes were measured in vitro at different external potassium concentrations.
2. At nominally zero external potassium concentrations, the ouabain-sensitive sodium efflux was reduced to less than 20% of its maximum value. There was evidence that under these conditions a ouabain-sensitive sodium-sodium exchange occurs.
3. Both total and ouabain-insensitive potassium influx increased with increasing external potassium concentration. The ouabain-sensitive potassium influx showed saturation.
4. Ouabain-insensitive potassium efflux was also stimulated by increasing the external potassium concentration, suggesting significant potassium-potassium exchange at physiological external potassium concentrations.
A Comparison of Natriuresis after Oral and Intravenous Sodium Loading in Sodium-Depleted Man: Evidence for a Gastrointestinal or Portal Monitor of Sodium Intake
Authors: Lennane R. J. , Carey R. M. , Goodwin T. J. , Peart W. S. 
Published: August 2015

1. Dietary sodium reduction in man is followed by rapid conservation of sodium by the kidneys. The rapidity of this response suggests that the gastrointestinal tract is involved in early recognition of changes in sodium intake or in mediation of the compensatory response.
2. In order to test the hypothesis, 100 mmol of sodium was given to normal volunteers in balance on a low-sodium diet (5 mmol/24 h): the dose was given either orally or intravenously.
3. Those who received their sodium orally excreted it more rapidly than those who received it intravenously and the difference was most marked in the first 8 h after the dose.
4. This finding is consistent with the presence of an input receptor for sodium in the gastrointestinal tract.
Urinary Excretion of 17-Oxosteroids in Hereditary Coproporphyria
Authors: Paxton J. W. , Moore M. R. , Beattie A. D. , Goldberg A. 
Published: August 2015

1. Urinary 17-oxosteroid conjugates were measured by gas-liquid chromatography in five patients with hereditary coproporphyria.
2. Three patients were in an acute attack and showed significantly increased excretion of sulphate or glucuronide conjugates of aetiocholanolone. There was increased excretion of several other related steroids but no consistent pattern was apparent.
3. In the two patients in remission, excretion of urinary 17-oxosteroids was not increased.
4. The ratio of total urinary aetiocholanolone to androsterone (5β:5α) was found to be significantly elevated for the three patients in an acute attack. Serial measurements were made in two of these patients and showed a highly significant linear correlation between this ratio and the urinary content of δ-aminolaevulic acid and porphobilinogen.
5. These observations suggest the involvement of the 17-oxosteroids, especially aetiocholanolone, in the pathogenesis of hereditary coproporphyria.
The Role of Baroreceptors and Chemoreceptors in the Regulation of the Cerebral Circulation
Authors: James I. M. , MacDonell Lindsay A. 
Published: August 2015

1. Ten experiments, each using two dogs, were performed to evaluate the effect of chemoreceptor and baroreceptor activity on the cerebral circulation.
2. The carotid bifurcation areas were vascularly isolated bilaterally and perfused with arterial blood from a second animal.
3. Bilateral vagotomy interrupted stimuli from the aortic group of receptors.
4. Administration of 5% carbon dioxide to the donor animal resulted in an increase in cerebral (cortical) blood flow in the recipient.
5. A change in the arterial perfusion pressure from the donor resulted in a reciprocal change in the cerebral blood flow of the recipient. These changes were abolished by sectioning the sinus nerves.
The Influence of Potassium on the Renal Vasculature and the Adrenal Gland, and Their Responsiveness to Angiotensin II in Normal Man
Authors: Hollenberg N. K. , Williams G. , Burger B. , Hooshmand I. 
Published: August 2015

1. The effect of modifying potassium intake on arterial plasma renin activity, angiotensin II and aldosterone concentrations, renal blood flow and their responses to exogenous angiotensin II has been assessed in twenty-six normal subjects.
2. Reduced potassium intake was associated with a significant increase in circulating renin activity and angiotensin II concentration and a significant reduction in renal blood flow. Conversely, a high potassium intake was associated with a significant increase in plasma aldosterone concentration and renal blood flow without alteration in plasma renin activity or angiotensin II concentration.
3. Reduced potassium intake decreased both the renal vascular and the adrenal response to infused angiotensin II. Conversely, an increased potassium intake enhanced the responsiveness of both systems.
4. The results suggest an important influence of potassium-induced renin-angiotensin system responses on both the renal vasculature and adrenal glomerulosa cell in normal man.
The Early Effects of Intravenous Frusemide on Central Haemodynamics, Venous Tone and Plasma Renin Activity
Authors: Hesse B. , Nielsen I. , Lund-Jacobsen H. 
Published: August 2015

1. Nine patients with clinically unimportant heart disease or benign essential hypertension were given frusemide intravenously during right-heart catheterization.
2. Pressures in both atria decreased rapidly and in parallel. The magnitude of the pressure decrease was clearly related to decrease in plasma volume loss.
3. Plasma renin activity increased significantly after 5 min (P < 0·01), but did not correlate with plasma volume loss.
4. Venous tone in the forearm was unchanged.
5. It is concluded that the pressure reduction was secondary to plasma volume depletion through diuresis and that increased plasma renin activity was mainly caused by intrarenal changes.
The Meaning of Dopamine β-Hydroxylase in Essential Hypertension
Authors: Alexandre J. M. , London G. M. , Chevillard C. , Lemaire P. , Safar M. E. , Weiss Y. 
Published: August 2015

1. Resting plasma dopamine β-hydroxylase (DBH) activity and haemodynamic parameters were studied in untreated borderline (twenty-nine) and permanent (twenty-seven) essential hypertensive patients. DBH was also measured in sixty-three apparently healthy subjects.
2. Mean DBH values were not significantly different between the groups.
3. Cardiac output, cardiopulmonary blood volume and the cardiopulmonary blood volume/total blood volume ratio (CPBV/TBV) were significantly higher in borderline than in permanent hypertensive patients.
4. In borderline hypertensive patients, plasma DBH activity was directly correlated with diastolic arterial pressure and with values of cardiac output, cardiopulmonary blood volume and CPBV/TBV ratio. No such correlations could be observed in the permanent hypertensive group.
5. These results suggest that plasma DBH activities in borderline hypertension mainly depend on the sympathetic activity responsible for the haemodynamic variations. Contrariwise, plasma DBH activities in permanent essential hypertensive patients appear to reflect other factors.
The Stimulation of Renin Secretion by Non-Vasocontrictor Infusions of Adrenaline and Noradrenaline in the Isolated Rat Kidney
Authors: Vandongen R. , Greenwood Dianne M. 
Published: August 2015

1. The effect of adrenaline and noradrenaline on renin secretion in the isolated perfused rat kidney was examined. The doses of catecholamines used were such that renal vasoconstriction and therefore increases in renal perfusion pressure were avoided. Under these conditions adrenaline and noradrenaline significantly increased renin secretion rates, compared with control experiments in which no catecholamine was infused.
2. Mean renal perfusion pressure during both adrenaline and noradrenaline infusion paralleled the control study by showing a progressive fall.
3. Administration of phenoxybenzamine did not impair the stimulation of renin secretion by adrenaline whereas this was prevented by racemic propranolol.
4. These observations suggest that catecholamines stimulate renin secretion by an intrarenal effect which is largely independent of changes in renal perfusion pressure. It is postulated that the beta-adrenoceptors mediating renin secretion are an integral component of the renin-producing cell.
Variations in Thyroid Function and Sleep in Healthy Young Men
Authors: Johns M. W. , Masterton J. P. , Paddle-Ledinek J. E. , Patel Y. C. , Winikoff D. , Malinek M. 
Published: August 2015

1. The total serum thyroxine, tri-iodothyronine resin uptake, total plasma protein concentration and the free thyroxine index (FTI) were determined repeatedly, at 07.15, 13.00 and 22.30 hours over 4 days, in six healthy young men.
2. There was a significant diurnal variation in the total serum thyroxine concentration but this reflected changes in the binding capacity of serum proteins and in the total plasma protein concentration which could be explained by changes of posture. The FTI, and presumably therefore the free thyroxine concentration, varied very little with the time of day.
3. The FTI varied significantly from day to day in three of the six subjects, presumably as a result of changes in thyroxine secretion because the serum binding capacity did not vary.
4. The subjects' sleep at night was assessed by electro-encephalogram. On days when the FTI was highest for a particular subject his sleep was more fragmented by spontaneous awakenings, the amount of rapid-eye-movement sleep was reduced and that of delta-wave sleep was increased, implying that variations in thyroid function over a period of a few days in healthy subjects can be of physiological significance. The cause of these variations is uncertain.