bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Changes in Sodium Balance on Potassium/Aldosterone Dose-Response Curves in the Dog
Authors: Nicholls M. G. , Tree M. , Livesey J. H. , Fraser R. , Morton J. J. , Robertson J. I. S. 
Published: August 2015

1. Potassium was infused intravenously in an incremental fashion and the plasma aldosterone responses were measured in conscious beagle dogs at five different intakes of dietary sodium.
2. Potassium/aldosterone dose—response curves were constructed for each dietary sodium regimen.
3. The rate of increase of plasma potassium during graded potassium infusion became progressively greater with increasing sodium depletion.
4. Regression lines of plasma aldosterone on plasma potassium were progressively elevated and steepened with increasing sodium depletion.
5. The alteration of these dose-response curves could in part have been the result of chronic elevation of plasma potassium and angiotensin II, and depression of plasma sodium, with sodium deprivation.
6. By contrast, acute changes in plasma angiotensin II or sodium concentrations across incremental infusions of potassium did not explain the progressive changes in the potassium/aldosterone dose—response curves.
7. The steepest part of the plasma aldosterone response curve was in the plasma potassium range 4–6 mmol/l.
8. Maximum achieved aldosterone levels were similar to or greater than those attained during angiotensin II infusion in previous studies in beagle dogs.
9. Potassium, like angiotensin II and adrenocorticotropic hormone, becomes a more effective stimulus to aldosterone with sodium depletion, thereby facilitating the preservation of sodium homoeostasis.
A Biochemical and Immunological Investigation into the Physiological Basis of the Increased Albumin Filtration Induced in Hyperalbuminaemic Female Wistar Rats
Authors: Lawrence Gillian M. , Brewer D. B. 
Published: August 2015

1. The level of proteinuria induced in female Wistar rats after bovine albumin injection intraperitoneally was highly dose dependent.
2. The proteinuria remained highly selective, with albumin constituting approximately 90% of the total protein excreted, even in the most severely affected rats.
3. Calculations relating the amount of bovine albumin available in the serum for filtration to the amount excreted in the urine indicated that complete saturation of the reticuloendothelial and tubular protein reabsorption systems-5-have occurred during the course of the 5 day injection period in rats given more than 3.5 mg of bovine albumin day−1 g−1 body wt.
4. When this situation was attained there appeared to be no further increase in glomerular permeability to either rat or bovine albumin and an equilibrium state seemed to exist where, when serum albumin levels were raised above the normal level, all the excess albumin passed across the glomerular filter to be excreted in the urine.
5. The passage of these large quantities of albumin across the glomerular filter-5-have resulted not from ultrastructural damage to the filter itself but rather from the generation of vastly increased concentration gradients across the glomerular basement membrane, which were sufficiently large to overcome the electrostatic repulsive forces which normally severely restrict albumin filtration.
Inhibitory Activity of Human Urine on Calcium Oxalate Crystal Growth: Effects of Sodium Urate and Uric Acid
Authors: Fellström B. , Backman U. , Danielson B. G. , Holmgren K. , Ljunghall S. , WikströM B. 
Published: August 2015

1. Freshly voided urine from healthy subjects was pooled and ultrafiltered (10 000 daltons). The ultrafiltrable and the macromolecular portions were preincubated with calcium oxalate, uric acid and sodium urate crystals and the effects on the inhibitory activity of calcium oxalate crystal growth assessed by monitoring the disappearance of [14C]oxalate from the solution.
2. The inhibitory activity of the ultrafiltrate was higher than that of the urinary macro-molecular fraction. Both uninhibited and inhibited crystal growth processes followed second-order kinetics.
3. Calcium oxalate crystals adsorbed almost all the urinary macromolecular inhibitors whereas sodium urate or uric acid crystals adsorbed only 10–20%.
4. In the presence of a metastable solution of calcium oxalate, the incubation of the urinary macromolecular fraction with sodium urate crystals caused a pronounced reduction in the inhibitory activity. A similar effect was seen with uric acid crystals, but to a lesser degree.
5. We conclude that the effect of sodium urate or uric acid crystals alone on naturally occurring urinary macromolecular inhibitors of calcium oxalate crystal growth is weak, but that in the presence of metastable calcium oxalate this is greatly enhanced. A substantial adsorption of the inhibitors on to the crystals is suggested, possibly secondary to epitaxial growth of calcium oxalate on the surface of the urate crystals.
Maximal Biliary Secretion of Bilirubin in the Anaesthetized Rat: Dependence on UDP-glucuronosyltransferase Activity
Authors: Van Steenbergen W. , Fevery J. 
Published: August 2015

1. Hepatic bilirubin UDP-glucuronosyl transferase activity in heterozygous Gunn rats (Jj) was only two-thirds of that in the parent Wistar rats (JJ). The former excreted only 30% of their bilirubin conjugates into bile as diglucuronide in contrast to 48% in the Wistar rats. As similar changes have been observed in Gilbert's syndrome, heterozygous Gunn rats can be used as a model for this disorder.
2. Treatment for 2 weeks with phenobarbitone or glutethimide produced a 2.6- and a 1.3-fold increase in hepatic glucuronosyltransferase activity in Wistar and heterozygous Gunn rats respectively. Bilirubin apparent maximal biliary secretory capacity (Tm) was enhanced in all animals pretreated with the enzyme inducing agents. A relationship was found between the transferase activity and the Tm value. At low transferase activities (Jj rats) a small increase in enzyme activity was accompanied by a marked enhancement of the Tm; at higher enzyme activities (Wistar rats) the increase in Tm. was less pronounced. These data suggest that the maximal biliary secretion of bilirubin is dependent on conjugation capacity, and that the currently used assay of the digitonin-activiated glucuronosyltransferase yields physiologically meaningful data.
3. In general, bilirubin diglucuronide excretion in bile increased in parallel with higher hepatic glucuronosyltransferase activities, as previously documented in man. However, this relationship was not present in glutethimide-pretreated animals. A high bilirubin load decreased the diglucuronide output in heterozygous Gunn rats. These observations demonstrate that the ratio of mono- to di-glucuronide in bile is mainly but not solely determined by the transferase activity.
Urea, Glucose and Alanine Kinetics in Man: Effects of Glucose Infusion
Authors: Royle G. T. , Molnar J. A. , Wolfe Marta H. , Wolfe R. R. , Burke J. F. 
Published: August 2015

1. The simultaneous effects of an intravenous glucose infusion on plasma urea, glucose and alanine kinetics were investigated in normal post-absorptive man.
2. The primed constant intravenous infusion of compounds labelled with stable isotopes, [15N2]urea, [6-2H]glucose and [3-13C]alanine, was used.
3. The rate of appearance of glucose and urea in the plasma was rapidly reduced by the 17.7 μUmol min−1 kg−1 glucose infusion.
4. In contrast, during the glucose infusion there was an increased rate of appearance of alanine in the plasma, and an increased percentage of glucose carbon atoms derived from alanine.
5. Reduced production of glucose and urea during the glucose infusion was not due to decreased gluconeogenesis from alanine.
Tubular Function in Glycerol Induced Acute Renal Failure in Rats: Effect of Saline Loading and Prior Acute Renal Failure
Authors: Westenfelder C. , Crawford P. A. , Hamburger R. K. , Baranowski R. L. , Kurtzman N. A. 
Published: August 2015

1. Chronic saline loading and prior induction of acute renal failure are manoeuvres which have been reported to protect against the development of acute renal failure. The underlying mechanisms are unclear. The purpose of the present study was to examine the effect of these protective manoeuvres on glomerular filtration rate (GFR) and proximal and distal tubular function in the glycerol-induced model of acute renal failure.
2. Acute renal failure was induced (50% glycerol, 10 ml/kg body wt. intramuscularly) in three groups of rats: group 1, water drinking; group 2, saline loaded (1% NaCl as drinking fluid for 5 weeks); group 3, rechallenged 7–15 days after a first dose of glycerol, when blood urea nitrogen levels had returned to normal. Control animals in group 3 received only the first glycerol injection, then, like the controls in groups 1 and 2, they were given 0.9% NaCl solution (10 ml/kg body wt. intramuscularly). All animals were then studied 24 h after glycerol or saline injection.
3. Glycerol caused a significant fall in GFR in all three groups (78% group 1; 64% group 2; 59% group 3); blood urea nitrogen levels rose significantly. Saline-loaded animals with acute renal failure (group 2) exhibited glycosuria with normal blood-sugar levels and a striking depression in maximal tubular glucose reabsorption. The capacity to reabsorb HCO−3 was depressed both before and during HCO−3 loading. Distal acidification as assessed by the urine to blood gradient of Pco2 (U—B Pco2) was normal during HCO−3 loading (urine pH 7.8). The presence of hyperchloraemic metabolic acidosis demonstrated that these animals developed proximal renal tubular acidosis. Glycerol-reinjected rats with acute renal failure (group 3) reabsorbed glucose and HCO−3 normally and exhibited normal distal tubule acidification.
4. We conclude from these data that a prior episode of acute renal failure protects proximal tubules against a second glycerol challenge, whereas chronic saline loading is without this protective effect. Both the underlying mechanism for this tubular cell resistance (against a second glycerol challenge) and the role of proximal tubular function in the pathogenesis of acute renal failure remain unclear.
Evidence of Altered Structure of the Erythrocyte Membrane in Spontaneously Hypertensive Rats
Authors: Orlov S. N. , Gulak P. V. , Litvinov I. S. , Postnov YU. V. 
Published: August 2015

1. The membrane structure of erythrocytes of rats with different forms of arterial hypertension was studied by means of two hydrophobic fluorescent probes (diphenylhexatriene and pyrene).
2. Microviscosity of hydrophobic areas of erythrocyte membrane of spontaneously hypertensive rats was found to be increased compared with that of membranes from normotensive control rats.
3. No alterations of membrane structure of erythrocytes of deoxycorticosterone-treated rats and renal hypertensive rats were found.
Influence of Respiratory Heat Transfer on Thermogenesis and Heat Storage after Cold Immersion
Authors: Morrison J. B. , Conn M. L. , Hayes P. A. 
Published: August 2015

1. Ten male subjects were cooled on three occasions to a rectal temperature of 35°C by immersion to the neck in water at 11·3°C. The subjects were rewarmed for 60 min, once by metabolic heat production alone (shivering), once by inhalation rewarming with spontaneous breathing of saturated air at 47°C (control) and once by inhalation rewarming with ventilation regulated at 40 litres/min by respiring a controlled fraction of CO2 (hyperventilation).
2. Metabolic heat production was substantially reduced by inhalation rewarming (P &lt; 0·05), from 913 kJ when shivering to 766 kJ (control) and 613 kJ when hyperventilating. The fall in metabolic heat production was greater than the corresponding respiratory heat gain, which increased from a loss of 41 kJ when shivering to gains of 85 kJ (control) and 169 kJ (hyperventilation).
3. As differences in mean skin temperatures were small (&lt;1·0°C), it is concluded that the lower metabolic heat production in response to increased respiratory heat input must result from more rapid central temperature gains. This conclusion is supported by the relative values of rectal and tympanic temperatures. It was calculated that the percentage of the total heat supply which was donated to the core increased from 13% during shivering to 16% for the control and 23% in hyperventilation. Results imply that respiratory heat input is more efficient than metabolic heat production in elevating central temperature.
An Estimate of the Endogenous Secretion Rate of Calcitonin in Man
Authors: Kanis J. A. , Heynen G. , Cundy T. , Cornet F. , Paterson A. , Russell R. G. G. 
Published: August 2015

1. The metabolic clearance rate (MCR) of human calcitonin was measured in 12 normal subjects and four patients with Paget's disease by the infusion of synthetic human calcitonin (15–40 μg/h for 2–24 h), and in 10 additional patients with Paget's disease from the disappearance rate of immunoreactive calcitonin from plasma after the intravenous injection of large doses of synthetic human calcitonin (0·5–1·0 mg).
2. The estimated MCR during the infusion studies (range 531–1224 litres/day) was similar to that calculated from the disappearance of large doses of synthetic human calcitonin injected intravenously in patients with Paget's disease (mean = 1035 litres/day; range = 593–1408 litres/day).
3. An eightfold range in the basal values of plasma immunoreactive calcitonin, in spite of the presence of a relatively constant MCR, suggests that the variation in basal plasma calcitonin was due principally to variation in the endogenous secretion rate for calcitonin.
4. The results suggest that the endogenous secretion rate for calcitonin is low in normal subjects (mean 124 ± sem 24 μg/day), and give a basis for selecting the doses of calcitonin which can be considered physiological.
Interpretation of Tracer Studies on Plasma Protein Turnover: Comparison of Methods and Optimization of Techniques
Authors: Reeve J. , Pussell B. , Gibbs G. P. , Peters D. K. 
Published: August 2015

1. A comparison of several published methods for analysing plasma protein turnover data has been undertaken, with particular reference to rapidly metabolized proteins such as members of the complement series.
2. With the exception of the equilibrium time method, most methods proved adequate for the determination of overall fractional catabolic rates. A further exception is that the renal clearance method becomes invalid when the fractional catabolic rate approaches the renal iodide clearance, but this may be the method of choice for slowly metabolized proteins if accurate urine collections can be ensured.
3. For the measurement of the ratio of extra-to intra-vascular protein pool size a clear preference emerged for the method of C. M. E. Matthews (1957, Physics in Medicine and Biology, 2, 36–53). For rapidly metabolized proteins the calculations must be preceded by a correction for the non-protein bound iodide retained in the intra- and extra-vascular spaces.
4. The accurate calculation of fractional catabolic rate in the extravascular pool generally requires more experimental data than are commonly collected as well as an accurate correction for non-protein bound label that remains unexcreted. Only two techniques hold promise of accurate results: Nosslin's rate equations method and a development of Vitek's deconvolution method described herein. Nosslin's integrated rate equations method is particularly affected by systematic errors in renal iodide clearance estimates and should probably not be further used for this purpose.
Relation of Arterial Pressure with Body Sodium, Body Potassium and Plasma Potassium in Essential Hypertension
Authors: Beretta-Piccoli C. , Davies D. L. , Boddy K. , Brown J. J. , Cumming A. M. M. , East B. W. , Fraser R. , Lever A. F. , Padfield P. L. , Semple P. F. , Robertson J. I. S. , Weidmann P. , Williams E. D. 
Published: August 2015

1. Exchangeable sodium (NaE), plasma electrolytes and arterial pressure were measured in 121 normal subjects and 91 patients with untreated essential hypertension (diastolic &gt;100 mmHg), 21 of whom had low-renin hypertension. Plasma concentrations of renin, angiotensin II and aldosterone were measured in all hypertensive patients, total body sodium, total body potassium and exchangeable potassium (KE) in some patients.
2. Mean NaE was not different in normal and hypertensive subjects provided the two groups were matched for leanness index. In the subgroup of young hypertensive patients aged 35 years or less mean NaE was below normal. NaE was not related to arterial pressure in normal subjects but in hypertensive patients there were positive and significant correlations of arterial pressure with NaE and with total body sodium.
3. NaE and total body sodium increased with age in hypertensive but not in normal subjects. Partial regression analysis suggested that the correlation of NaE with arterial pressure was not explained by an influence of age.
4. Mean NaE was not increased and mean KE was not decreased in patients with low-renin hypertension.
5. Plasma potassium concentration, KE and total body potassium correlated inversely and significantly with blood pressure in hypertensive patients. These correlations were more marked in young than in old patients.
6. Multiple regression analysis showed that the combination of NaE and plasma potassium concentration ‘explained’ more of the variation of systolic blood pressure in hypertensive patients than it did in normal subjects. Plasma potassium concentration ‘explained’ more of the variation in young hypertensives and NaE ‘explained’ more in older patients.
7. Our findings suggest that changes of plasma and body potassium are important in the earlier stages of essential hypertension and that changes of body sodium become important later.
Mechanism of Pressor Effects of Intraventricular Injection of Angiotensin II in the Rat: Role of Vasopressin and Renal Nerves
Authors: Suzuki Hiromichi , Kondo Kazuoki , Handa Michiko , Kawabe Hiroshi , Saruta Takao 
Published: August 2015

1. The role of the kidney and vasopressin in the increase of blood pressure obtained when angiotensin II is injected intraventricularly into rats has been investigated.
2. Intraventricular injection of angiotensin II led to a significant increase in blood pressure in the control and all sham-operated rats compared with that in unilaterally nephrectomized, one-kidney denervated rats and bilaterally nephrectomized rats. The degree of increase in blood pressure in unilaterally nephrectomized, one-kidney denervated rats was equal to that in bilaterally nephrectomized rats.
3. The increase in blood pressure in the bilaterally nephrectomized rats lasted significantly longer than that in the control and unilaterally nephrectomized, one-kidney denervated rats.
4. In the bilaterally nephrectomized rats plasma vasopressin was still higher 30 min after the intraventricular injection of angiotensin II than that of the control and unilaterally nephrectomized, one-kidney denervated rats.
5. These results suggest that the rise in blood pressure observed after intraventricular injection of angiotensin II is due partly to stimulation of the renal sympathetic nervous system and partly to increase in plasma vasopressin concentration.
Absence of Production of Natriuretic Factor following Acute Saline Expansion in Nephrotic Rats
Authors: Favre H. , Gourjon M. 
Published: August 2015

1. The natriuretic activity of an extract from the kidneys was studied in control and nephrotic rats following acute saline expansion.
2. The natriuretic effect of a known natriuretic material prepared from human urine was evaluated in control and nephrotic rats.
3. After actute saline expansion, natriuretic activity was obtained only from the fractions extracted from the kidneys of the control rats.
4. Injection of natriuretic material produced a equal natriuretic response in both control and nephrotic rats.
Vascular Smooth Muscle Membrane Potential and a Ouabain-Like Humoral Factor in One-Kidney, One-Clip Hypertension in Rats
Authors: Pamnani Motilal B. , Harder David R. , Huot Stephen J. , Bryant Howard J. , Kutyna Francis A. , Haddy Francis J. 
Published: August 2015

1. Transmembrane potentials (Em) of vascular muscle cells in caudal arteries in vitro from one-kidney, one-clip hypertensive and one-kidney, sham-clipped normotensive rats were measured.
2. The Em recorded in hypertensive rats was significantly lower (depolarized) than that recorded in normotensive control rats.
3. Boiled plasma supernatants from hypertensive rats depolarized the muscle cells in normotensive caudal artery but had no effect on muscle cells in arteries from hypertensive rats.
4. Boiled plasma supernatants from normotensive control rats had no effect on the Em of either animal.
5. Ouabain depolarized muscle cells of the normotensive artery only and the magnitude of depolarization induced was nearly the same as that produced by the supernatant from the hypertensive animals.
6. These data suggest that a ouabain-like humoral substance may play a role in the pathophysiology of one-kidney, one-clip hypertension through a voltage-dependent mechanism.
Dependence of Renal Vasodilator Effect of Captopril on Prevailing Plasma Renin Level in the Dog: Influence of DOCA–Salt Treatment
Authors: Wong P. C. , Zimmerman B. G. 
Published: August 2015

1. The blood pressure and renal blood flow response to captopril (0·2 mg/kg, intravenously) was studied in low salt, normal, and high salt fed conscious dogs, and in a group of DOCA-salt treated dogs.
2. Mean arterial blood pressure was decreased and renal blood flow increased most in the low salt group, but significant changes were also obtained in the normal group. The high salt and DOCA-salt groups were only marginally affected by captopril.
3. When the data from all four groups of dogs were subjected to regression analysis, there was a significant relationship (r = 0·68) between the prevailing plasma renin activity and the increase in renal blood flow caused by captopril.
4. The results suggest that renal vasodilatation resulting from converting enzyme inhibition is mainly due to a decrease in the level of circulating angiotensin II, and that even in the normal conscious dog the prevailing plasma renin activity can affect blood pressure and renal blood flow.
Purine Synthesis De Novo in Lymphocytes from Patients with Gout
Authors: Gordon R. B. , Counsilman A. C. , Cross S. M. C. , Emmerson B. T. 
Published: August 2015

1. Variables that affect the measurement of purine synthesis de novo in human lymphocytes were studied and a reliable method of measurement of purine synthetic activity in these cells was established.
2. Purine synthesis de novo was measured as the rate of incorporation of [14C]formate into α-N-formylglycinamide ribonucleotide when further steps in the biosynthetic pathway had been blocked by azaserine. Incubation was carried out in a synthetic medium with a high phosphate concentration (25 mmol/l).
3. Purine synthesis de novo was measured in lymphocytes obtained on several occasions both from control subjects and from patients with gout, particularly those who tended to overproduce urate as suggested by high values of urinary urate.
4. Lymphocytes obtained from each individual on different occasions showed considerable variations in purine biosynthetic activity. This variation was such that there was no difference between the mean values obtained for the gouty subjects and the control subjects.
5. No correlation was obtained between the mean purine synthetic activity de novo in lymphocytes and either the serum urate concentration or the 24 h urinary urate excretion on a purine-free diet.
6. Apart from those with recognized enzyme mutations, no subgroup of the gouty population has been demonstrated in whom isolated lymphocytes demonstrate an intrinsic abnormality of purine synthesis de novo.