bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Concentration-Polarization on the Filtration of Proteins through Filters Constructed from Isolated Renal Basement Membrane
Authors: Cotter T. G. , Robinson G. B. 
Published: August 2015

1. Filters comprising multiple layers of rabbit renal tubular basement membrane were constructed with conventional pressure filtration chambers. The effects of concentration-polarization on the behaviour of these filters was assessed by studying the filtration of proteins and of serum under turbulent (stirred) and unstirred conditions.
2. With stirring bovine serum albumin was effectively rejected by the filter barriers (σ = 0.95) but rejection was diminished (σ = 0.18) without stirring. The hydraulic permeability of the filters also fell without stirring.
3. In the presence of horse immunoglobulin G, a wholly rejected protein, the rejection of cytochrome c was increased and hydraulic flux was reduced.
4. Filtration studies of serum showed that serum protein was effectively rejected with stirring (σ > 0.999) but rejection diminished when stirring ceased (σ = 0.98). Albumin was the only protein detected in the filtrate with stirring but α- and β-globulins appeared when stirring ceased.
5. These results show that concentration-polarization markedly affects the behaviour of these basement membrane filters in vitro, since without stirring a polarization layer of rejected protein is formed, which reduces hydraulic permeability and results in increased protein permeation through the filter.
Parallel Changes between Lipoprotein Lipase Activating Capacity and Lipid Concentrations in the Serum of Rats and Ferrets during Development and Dietary Manipulation
Authors: Cryer A. , Heather M. Jones 
Published: August 2015

1. The lipoprotein lipase activating capacity of serum from 5 to 22 day old rats and male ferrets fed on diets rich in either beef tallow or maize oil was significantly correlated with the triglyceride concentration in the serum.
2. These increases in activating capacity associated with increased serum triglyceride concentrations were similar to those reported for human serum.
Lack of Effect of Isometric Handgrip Exercise on the Responses of the Carotid Sinus Baroreceptor Reflex in Man
Authors: Ludbrook J. , Faris I. B. , Iannos J. , Jamieson G. G. , Russell W. J. 
Published: August 2015

1. The change in arterial pressure and heart rate resulting from alteration of carotid sinus transmural pressure by a median −34 mmHg and +33 mmHg by means of a variable-pressure neck chamber was tested in seven male volunteer subjects, at rest and during exertion of 35, 45 and 65% of maximum voluntary handgrip.
2. During 60 s of 35 and 45%, and during 30 s of 65%, of maximal voluntary handgrip there was virtually no alteration of the response of blood pressure to alteration in carotid sinus transmural pressure.
3. The bradycardic response to increase in carotid sinus transmural pressure was reduced at various times after the commencement of handgrip at 45 and 65% of maximum voluntary contraction.
4. It is concluded that a reduction in arterial baroreceptor reflex sensitivity does not play an important role in the initiation of the increase in arterial blood pressure and heart rate caused by isometric exercise.
5. The hypothesis is advanced that some of the cardiovascular changes in exercise may result from elevation of the central ‘set point’ for blood pressure.
A Comparison of Methods for Measurement of Rectal Potential Difference in Man: Effects of Rectal Infusion of Amiloride
Authors: Mohamed F. , McSorley P. , Warren D. J. 
Published: August 2015

1. Two methods for measurement of rectal potential difference in man were compared. A saline-filled catheter technique gave more reproducible results and was better tolerated by patients than the solid probe technique.
2. Infusion of amiloride at a concentration of 4 × 10−6 mol/l in saline produced a variable fall of potential difference in six normal subjects. Dose-response curves in two subjects showed that complete inhibition of rectal potential difference occurred at 4 × 10−5 mol/l and 4 × 10−6 mol/l respectively.
3. This finding provides additional evidence that rectal potential difference in man results from electrogenic ion transport across the mucosal epithelial cell.
Effect of Acute Ethanol Administration on Liver Oxidative Capacity in Rats
Authors: Videla L. A. 
Published: August 2015

1. The administration of a single oral dose of 2, 3, 4 or 5 g of ethanol/kg (43.5, 65.2, 87.0 or 108.7 mmol/kg respectively) to rats increases the rate of oxygen consumption by liver slices from animals killed 24–48 h later.
2. The increase in the rate of hepatic respiration can be blocked by incubation in a medium containing ouabain, an inhibitor of the sodium pump, or in a calcium-free medium.
3. The enhancement of oxygen uptake caused by a single dose of ethanol can be abolished by adrenalectomy or by prior administration of the α-adrenergic blocking agent phentolamine, and is markedly less in thyroidectomized animals.
4. It is suggested that the effect which is elicited by acute ethanol administration on respiration by liver slices is mediated by adrenaline and by thyroid hormones, both of which appear to exert a calorigenic effect by activation of the sodium pump. The results are discussed in relation to the changes in liver oxidative capacity induced by chronic alcohol ingestion.
A Study In Vitro of the Sodium Pump in Fulminant Hepatic Failure
Authors: Alam A. N. , Poston Lucilla , Wilkinson S. P. , Golindano C. G. , Williams R. 
Published: August 2015

1. The mechanism underlying the raised leucocyte sodium content in fulminant hepatic failure was studied by measurement of sodium fluxes, (Na+ + K+)-dependent adenosine triphosphatase activity, and leucocyte ATP content.
2. The rate constant for sodium efflux in the leucocytes was significantly reduced, and attributable to reduced activity of the enzyme (Na+ + K+)-ATPase. Leucocyte ATP content was not significantly different from that of control cells.
3. Incubation of cells from patients in the sera of normal subjects resulted in a reversal of these changes. Inhibition of the leucocyte sodium efflux rate constants and (Na+ + K+)-ATPase of normal cells was achieved by incubation in sera from patients.
4. We suggest that the raised sodium content of leucocytes in fulminant hepatic failure is attributable to a defective sodium pumping mechanism, possibly due to a circulating toxin.
Identification of a Delivery-Related Influence on Proximal Tubular Reabsorption during Expansion with Hyperoncotic Albumin in the Rat
Authors: Donohoe J. F. , Lefavour Gertrude S. , Cortell S. , Gennari F. J. 
Published: August 2015

1. Proximal tubular fluid flow rate was deliberately reduced to control values in rats after acute volume expansion with hyperoncotic albumin, to determine if the depression of reabsorption by albumin-induced expansion could be uncovered by preventing the associated increase in filtrate delivery. Tubular fluid flow was reduced either by reducing renal perfusion pressures or by diverting fluid from early proximal tubular sites.
2. In the absence of controlled delivery, expansion with hyperoncotic albumin increased nephron filtration rate, reduced the TF/P inulin ratio, but had no effect on absolute reabsorptive rate. When proximal tubular flow rate was returned to control values by a simultaneous early collection, fractional reabsorption remained depressed. By contrast, when tubular flow was maintained at control values by reducing renal perfusion pressure, the large fall in fractional reabsorption was blocked.
3. The results indicate that expansion with hyperoncotic albumin depresses proximal tubular reabsorption independently of delivery rate into the proximal tubule, but that this effect can be reversed by a reduction in renal perfusion pressure. These observations unify the results of previous studies and indicate the presence of a delivery-related influence on proximal reabsorption. The inability to detect a reduction in absolute reabsorption when nephron filtration rate is increased during expansion with hyperoncotic albumin is probably due to the countervailing influence of increased delivery rate, which raised reabsorptive rate.
Adenine and Adenosine Metabolism in Intact Erythrocytes Deficient in Adenosine Monophosphate-Pyrophosphate Phosphoribosyltransferase: A Study of Two Families
Authors: Dean B. M. , Perrett D. , Simmonds H. Anne , Sahota A. , Van Acker K. J. 
Published: August 2015

1. We have studied the metabolism of adenine and adenosine in intact erythrocytes from three children and four adults of two separate families. The children were homozygotes for a deficiency of AMP-pyrophosphate phosphoribosyltransferase (adenine phosphoribosyltransferase, EC 2.4.2.7), and the parents heterozygotes.
2. In this intact cell system at physiological concentrations of inorganic phosphate (Pi) and adenine heterozygote adenine phosphoribosyltransferase activity was normal, whereas at higher adenine concentrations (1.0–10 μmol/l) the four heterozygotes showed approximately 50% of control activity. At high concentrations of Pi (18 mmol/l) and adenine (10 μmol/l) and with extended incubation heterozygote activity was again indistinguishable from normal. Activity of the enzyme in homozygotes was negligible under all these conditions.
3. Formation of inosine 5′-monophosphate from [8-14C]hypoxanthine at high Pi concentrations was normal in both homozygotes and heterozygotes. Thus no abnormality of either of the enzymes IMP—pyrophosphate phosphoribosyltransferase (hypoxanthine phosphoribosyltransferase, EC 2.4.2.8) or phosphoribosyl pyrophosphate synthetase (ribose phosphate pyrophosphokinase, EC 2.7.6.1) was found.
4. To ascertain whether deficiency of adenine phosphoribosyltransferase was linked with enhanced conversion of adenosine into adenine nucleotides at the expense of its deamination pathways, the complete metabolism of [8-14C]adenosine was studied over the range 0.1–9.0 μmol/l. No such increase was observed for either heterozygotes or homozygotes.
5. Insignificant formation of either [8-14C]-adenine from [8-14C]adenosine or vice versa in the erythrocytes of homozygotes lacking adenine phosphoribosyltransferase but capable of forming hypoxathine from adenosine, supports the concept that adenine and adenosine are not directly interconvertible and do not utilize purine nucleoside phosphorylase (EC 2.4.2.1) in erythrocytes.
6. Measurement of erythrocyte nucleotide concentrations by high-performance liquid chromatography revealed no obvious abnormalities. ATP:ADP:AMP proportions were normal (approximately 10:1:0.1) and the total adenine nucleotide pool was at the lower limit of the normal range for both homozygotes and heterozygotes. These observations imply that deficiency of adenine phosphoribosyltransferase does not grossly affect adenine nucleotides synthesis in the erythrocyte.
Altered Activity of the Sodium-Potassium Pump in Arteries of Rats with Steroid Hypertension
Authors: Pamnani Motilal B. , Clough David L. , Haddy Francis J. 
Published: August 2015

1. Ouabain-sensitive uptake of 86Rb, a measure of the Na+—K+ pump activity, was studied in tail arteries of rats made hypertensive with deoxycorticosterone and saline.
2. Decreased activity of the ouabain-sensitive Na+—K+ pump supports the hypothesis that the activity of Na+—K+ pump is suppressed in volume-expanded hypertension.
The Effects of Prednisolone on the Rat Enterocyte at a Subcellular Level
Authors: Batt R. M. , Wells G. , Peters T. J. 
Published: August 2015

1. Enterocytes, isolated from the proximal jejunum and distal ileum of normal and prednisolone-treated rats, were homogenized and fractionated by isopycnic centrifugation on sucrose density gradients. The distributions of marker enzymes for the principal subcellular organelles, RNA and protein were determined and related to the activities per enterocyte.
2. In enterocytes from the jejunum and ileum of prednisolone-treated animals the activities of particulate brush-border enzymes and of both soluble and mitochondrial malate dehydrogenase were increased compared with those of the control system. The equilibrium density of the brush borders was enhanced in the prednisolone-treated jejunum. The modal densities of the other organelles were unaltered by prednisolone administration.
3. There was a large increase in the total RNA content of enterocytes from the jejunum and ileum of prednisolone-treated animals. This was predominantly associated with a distinct particulate component, indicative of a proliferation of the rough endoplasmic reticulum and consistent with an enhanced rate of protein synthesis.
4. Studies of latent brush-border enzyme activities, the mechanical fragility of isolated brush borders and electron microscopy suggest that steroid administration results in no marked alterations in the gross conformation of the brush- border membrane or in the orientation of the enzymes within the membrane.
Haemodynamics of Orally-Active Converting Enzyme Inhibitor (SQ 14225) in Hypertensive Patients
Authors: Cody R. J. , Tarazi R. C. , Bravo E. L. , Fouad F. M. 
Published: August 2015

1. The haemodynamic effects of oral converting enzyme inhibitor (SQ 14225) were assessed in eight patients with severe essential or renovascular hypertension.
2. Mean arterial pressure fell (149 ± 5 to 127 ± 8 mmHg, P < 0.02), because of a fall in total peripheral resistance (6.9 ± 0.53 to 5.7 ± 0.40 kPa 1-1 s m2) without a significant change in cardiac index. Two of the eight patients were non-responders without pressure reduction or a haemodynamic change. Sodium restriction (10 mmol/day) while the same dose of SQ 14225 was continued further lowered arterial pressure (137 ± 8 to 111 ± 12 mmHg, P < 0.05) through further resistance reduction (6.5 ± 0.53 to 5.2 ± 0.40 kPa l−1 sm2, P < 0.05).
3. Haemodynamic responses to head-up tilt (increased heart rate and resistance, decreased cardiac index) were unaffected by SQ 14225 regardless of sodium intake.
4. The pattern of reduction in peripheral resistance, with unchanged cardiac index, was similar to that produced by vasodilators acting at both arteriolar and venular levels.
Evidence for an Hepatic Anti-Ketogenic Effect of Insulin in Man
Authors: Elkeles R. S. , Chalmers R. A. , Hambley J. 
Published: August 2015

1. Infusion of a triglyceride emulsion (Intralipid) into overnight fasted normal subjects produced a rise in plasma free fatty acids (FFA) and blood ketones.
2. Glucose given orally 60 min after the start of the Intralipid infusion produced a sharp fall in blood ketones without much change in plasma FFA.
3. An infusion of glucagon given together with Intralipid did not alter the reduction in blood ketones produced by oral glucose in normal subjects.
4. Oral glucose given 60 min after the start of the Intralipid infusion in three insulin-requiring diabetic subjects produced no fall in blood ketones.
5. The results suggest that glucose prevents the increase in blood ketones after Intralipid through an increase in insulin secretion rather than through a suppression of glucagon or as a direct effect of glucose.
6. It is most likely that the effect of insulin is to inhibit hepatic ketogenesis.
Protective Effect of Prostaglandin [PGE2] in Glycerol-Induced Acute Renal Failure in Rats
Authors: Werb R. , Clark W. F. , Lindsay R. M. , Jones E. O. P. , Turnbull D. I. , Linton A. L. 
Published: August 2015

1. Acute renal failure was induced in female Sprague—Dawley rats by the subcutaneous injection of glycerol.
2. Four groups of rats were studied; all animals received a glycerol challenge. Group A (control) were sham-operated only, group B received an infusion of sodium chloride solution (150 mmol/l; saline) for 24 h, group C received an infusion containing prostaglandin E2 (PGE2, 1.7 μmol/l) in saline and group D a solution containing PGE2 (3.4 μmol/l) in saline.
3. All rats were killed 48 h after glycerol challenge. The degree of renal impairment was assessed by serum creatinine concentration, which did not differ in sham-operated animals and the group receiving saline alone. The group of rats receiving the lower dose of PGE2 has a significantly lower mean serum creatinine concentration than the saline-infused control rats (P < 0.0025). Creatinine concentration was further lowered by the higher dose of PGE2 but there was not a significant difference in the number of rats showing severe tubular necrosis histologically.
4. The study demonstrates that intravenous infusion of prostaglandin E2 has a protective influence on glycerol-induced renal failure in the rat; the protection afforded may be due to the vasodilator effect of PGE2 and/or an effect on glomerular permeability.
Plasma Noradrenaline and Adrenaline and β-Adrenoreceptor Responsiveness in Renin Subgroups of Essential Hypertension
Authors: Bühler F. R. , Bertel O. , Kiowski D. W. 
Published: August 2015

1. Plasma noradrenaline and adrenaline responses to graded exercise, reflecting sympathoneural and adrenal activity, were compared with β-adrenoreceptor-mediated renin and heart-rate responses in 33 patients with essential hypertension and either high (n = 13), normal (n = 15) or low (n = 5) renin—sodium index. β-adrenoreceptor responsiveness, was assessed using the chronotropic dose of isoprenaline which increased heart rate by 25 beats/min (CD25).
2. No significant differences in adrenaline were found among the renin subgroups either at rest or during equi-effective exercise stimulation, though values in the older low-renin patients tended to be lower.
3. Plasma noradrenaline at rest or exercise was similar in the renin subgroups. This contrasted with the normal exercise tachycardia and hyper-responsive renin in the high renin patients and the blunted exercise tachycardia and reduced renin response in the normal and low renin patients.
4. The CD25 of isoprenaline was 2·5 ± 2·2 sd μg/m2 in the high, 3·1 ± 4·4 in the normal and 4·5 ± 5·9 in the low renin group.
5. Older age and a longer history of hypertension may be associated with a transition from a high to a low and hyporesponsive renin—angiotensin system, with diminishing β-adrenoreceptor sensitivity. In the presence of deficient β-adrenoreceptors, a normal or slightly elevated sympathetic nerve activity may act predominantly via α-adrenoreceptor-mediated vasoconstriction, enhanced by structural vessel changes.
Noradrenaline Secretion by the Human Kidney
Authors: De Leeuw P. W. , Falke H. E. , Punt R. , Birkenhäger W. H. 
Published: August 2015

1. In 20 subjects with uncomplicated essential hypertension, 10 of whom were on propranolol treatment, several blood samples were drawn simultaneously from the renal artery and vein after angiographic studies. In these samples we determined concentrations of noradrenaline, active renin, aldosterone and cortisol.
2. Renal blood flow was measured in all patients by Hippuran-clearance and xenon-washout.
3. Despite marked variations in the arteriovenous difference of noradrenaline, it was apparent in both groups that the kidney is able to release noradrenaline.
4. In the propranolol-treated group noradrenaline secretion by the kidney was enhanced when compared with untreated hypertensive patients.
The Kinetics of Plasma Noradrenaline in Normal and Hypertensive Subjects
Authors: Ghione S. , Palombo C. , Pellegrini M. , Fommei E. , Pilo A. , Donato L. 
Published: August 2015

1. The kinetics of plasma noradrenaline have been determined in normal and essential hypertensive patients by intravenous injection of tritiated noradrenaline and serial mixed venous sampling.
2. The metabolic clearance rate of plasma noradrenaline in normal subjects was approximately 1·1 min−1 m−2, whereas in essential hypertensive patients it was significantly reduced to approximately 0·61 min−1 m−2.
3. Metabolic clearance rate was negatively correlated to mean arterial blood pressure and total peripheral resistances.
4. Particularly low values of metabolic clearance rate were found in two patients with congestive heart failure and one with phaeochromocytoma.
5. We propose that the access of plasma noradrenaline to the main removal mechanisms takes place in competition with the flow of unlabelled endogenous noradrenaline directly released by nerve endings. The slower removal of plasma noradrenaline in essential hypertension could then express a larger release of endogenous noradrenaline in this condition.
Activation of Inactive Plasma Renin: Evidence that Both Cryoactivation and Acid-Activation Work by Liberating a Neutral Serine Protease from Endogenous Inhibitors
Authors: Atlas Steven A. , Laragh John H. , Sealey Jean E. 
Published: August 2015

1. We have found that ‘acid’-activation of inactive human plasma renin is a two-phase process. About 30% of activation occurs during dialysis to pH 3·3; the remaining 70% occurs at alkaline pH.
2. The ‘alkaline phase’ of activation has a pH optimum between 7·5 and 8·4. It is inhibited by unacidified plasma and by soya-bean or lima-bean trypsin inhibitors.
3. ‘Cryoactivation’ of inactive plasma renin, which occurs at −4°C and alkaline pH, is also inhibited by soya-bean or lima-bean trypsin inhibitors and by the serine protease inhibitors di-isopropylphosphorofluoridate and benzamidine.
4. Thus endogenous neutral serine proteases participate in the activation of inactive plasma renin in vitro. Their action is prevented in the circulation by inhibitors which are inactivated by acid or cold.
Different Responses of Active and Inactive Plasma Renin to Various Stimuli
Authors: Rumpf K. W. , Schächterle B. , Schmidt S. , Becker K. , Scheler F. 
Published: August 2015

1. The response of active and inactive plasma renin to orthostasis and frusemide and to inhibition of prostaglandin synthesis by indomethacin was tested in normal human volunteers.
2. Active renin increased by orthostasis and frusemide and decreased by indomethacin. The latter also blunted the increase of active renin after stimuli.
3. Inactive renin was slightly increased by orthostasis, but was not significantly influenced by acute administration of frusemide or inhibition of prostaglandin synthesis by indomethacin.
4. The results show differences in the response of active and inactive renin to stimuli and suppression. Opposite changes of active and inactive renin were not observed in the experimental conditions studied.
Steroidogenic and Pressor Activity of Angiotensin Analogues in the Rat
Authors: Khairallah P. A. , Khosla M. C. , Bumpus F. M. , Tait J. F. , Tait S. A. S. 
Published: August 2015

1. A classical 6 point assay in vitro for measuring aldosterone stimulating activity has been developed.
2. The steroidogenic potency of Ile5-angiotensin II was 62% of that given by Val5-angiotensin II. Ile5-angiotensin III (Des-Asp1-Ile5-angiotensin II) was likewise 50% as active as Val5-angiotensin III (Des-Asp1-Val5-angiotensin II). Similar results were obtained in the pressor and myotropic assays.
3. Ile5-angiotensin III and Val5-angiotensin III had only 7% and 16% respectively of the steroidogenic activity of Val5-angiotensin II.
4. Sar1-Ile5-angiotensin II was 2·3 times as potent as Val5-angiotensin II in aldosterone-stimulating activity. The corresponding activities of Me2-Gly1-angiotensin II, Pro1-angiotensin II and Pro31-angiotensin II were 71%, 15% and 3% of Val5-angiotensin II respectively.
Changes in Cardiac Output during the Development of Renal Hypertension in Sodium-Depleted Dogs
Authors: Davis James O. , Stephens Gregory A. , Freeman Ronald H. , Deforrest Jack M. 
Published: August 2015

1. Chronic renovascular hypertension developed in uninephrectomized, sodium-depleted dogs in association with a decrease in cardiac output.
2. With sodium and volume repletion of these animals, cardiac output returned to normal but the high level of arterial pressure was unchanged; consequently, the peripheral arterioles dilated.
3. These observations provide evidence against the theory of whole-body autoregulation.