bluuebunny/crossref_metadata_2025_split huggingface dataset:
Absorption and Metabolism of Allopurinol and Oxypurinol by Rat Jejunum in Vitro: Effects on Uric Acid Transport
Authors: Shaw M. I. , Parsons D. S. 
Published: August 2015

1. The transport and metabolism of allopurinol and oxypurinol have been examined in a preparation of adult rat jejunum in vitro. When present in the lumen (50–500 μmol/l) allopurinol appeared in the serosal secretions at lower concentrations, together with its metabolite oxypurinol and an unidentified substance. Oxypurinol in the lumen (1.4–430 μmol/l) was transported into the serosal secretions and at luminal concentrations below approximately 150 μmol/l was concentrated in the secretions. The transport of oxypurinol into serosal secretions was greater than that of allopurinol.
2. Allopurinol and oxypurinol decreased the appearance of urate, in the serosal secretions and the luminal fluid, by an amount which was greater than the concomitant increase in oxypurines; they increased the rate constant of the mono-exponential washout of endogenous urate and induced purine secretion into the lumen.
3. The transport of uric acid from the lumen into the serosal secretions was inhibited by allopurinol and oxypurinol. With allopurinol the specific radioactivity (14C) of urate in the serosal secretions approached that in the lumen; with oxypurinol the specific radioactivity was approximately 70% that in the lumen. There was no evidence for the uphill movement of urate from the lumen.
The Stimulation of Na+, K+-ATPase Activity in the Medulla of the Rat Kidney by [arginine] Vasopressin and Its Analogues
Authors: Pippard Corinna , Baylis P. H. 
Published: August 2015

1. Total and Na+,K+-ATPase activities have been measured in sections (10 μm thick) from blocks of rat kidney cultured for 5 h at 37°C, pH 7.5, in Glasgow Eagle's Minimum Essential Medium.
2. Synthetic [arginine]vasopressin ([Arg]VP) stimulated ATPase activity in the thick tubular cells of the renal outer medulla over the concentration range 0.01-10 fmol/l, but failed to affect ATPase activity in the proximal and distal convoluted tubules of the cortex.
3. The increase in medullary total ATPase activity induced by [Arg]VP and its analogues was wholly due to stimulation of Na+,K+-ATPase activity.
4. Stimulation of medullary ATPase activity was blocked by [Arg]VP antiserum.
5. The [Arg]VP analogues desmopressin, [lysine]vasopressin, [arginine]vasotocin and oxytocin stimulated medullary Na+,K+-ATPase activity, the three last-named analogues being considerably less potent than [Arg]VP.
A Method for the Study of Cation Transport in vivo: Effects of Digoxin Administration and of Chronic Renal Failure on the Disposition of An Oral Load of Rubidium Chloride
Authors: Boon N. A. , Aronson J. K. , Hallis K. F. , White N. J. , Raine A. E. G. , Grahame-Smith D. G. 
Published: August 2015

1. In order to study cation transport in vivo we have measured the changes in plasma and intra-erythrocytic rubidium concentrations following an oral load of rubidium chloride. The changes in plasma rubidium concentration are related to the distribution of rubidium to all the body tissues and the changes in intra-erythrocytic rubidium concentrations provide an example of rubidium uptake by one particular tissue.
2. In eight healthy volunteers pretreatment with a loading dose of digoxin (20 μg/kg) enhanced the rise in plasma rubidium concentrations and attenuated the rise in intra-erythrocytic rubidium concentrations after the oral load of rubidium chloride.
3. Ten patients with chronic renal failure, compared with a well-matched control group, were found to have changes similar to, but more marked than, those caused by digoxin, i.e. a much greater rise in plasma rubidium concentrations and a much smaller rise in intra-erythrocytic rubidium concentrations, after the oral load of rubidium chloride.
4. These findings are consistent with widespread reduction in Na+,K+-ATPase activity in subjects who have taken a loading dose of digoxin and patients with chronic renal failure. They are, therefore, consistent with the findings of previous studies in vitro and show that it is possible to demonstrate changes in cation transport in vivo.
Slowly digested carbohydrate food improves impaired carbohydrate tolerance in patients with cirrhosis
Authors: Jenkins D. J. A. , Thorne M. J. , Taylor R. H. , Bloom S. R. , Sarson D. L. , Jenkins A. L. , Blendis L. M. 
Published: August 2015

1. To test whether impaired carbohydrate tolerance in cirrhosis could be modified by dietary means ten cirrhotic patients, five of them taking insulin, took as breakfast either lentils or whole-meal bread and cottage cheese containing the same amount of carbohydrate and protein.
2. Lentils resulted in significantly diminished blood glucose, insulin (in those not on insulin) and gastric inhibitory peptide responses.
3. Enteroglucagon and neutrotensin levels were high with lentils, suggesting that absorption of lentil carbohydrate continued into the ileum with perhaps some malabsorption, so confuming the results of earlier studies in vitro.
4. However, breath hydrogen studies on a separate group of eight healthy volunteers indicated that the difference in carbohydrate malabsorption between lentil, and wholemeal bread was insignificant.
5. It is suggested that slowly digested carbo-hydrate foods, such as leguminous seeds, may minimize carbohydrate intolerance in patients with cirrhosis.
Receptors for angiotensin I1 on platelets from man
Authors: Ding Yuan , Kenyon Christopher J. , Semple Peter F. 
Published: August 2015

1. Platelets were prepared from peripheral venous blood on iso-osmotic density gradients of Percoll, resulting in a good recovery of cells (50–80%) which were relatively free of contaminating blood cells (erythrocyte &lt;0.1%, leucocyte &lt;0.1%).
2. At 22°C, specific binding of 125labelled angiotensin II (300 pmol/l) was time and temperature dependent, saturable, reversible and linear with cell concentration.
3. Scatchard analysis of saturation curves revealed a single class of binding sites with Kd 1.5 ± 0.4 × 10−10 mol/l and total binding capacity 6.3 ± 1.2 receptorslplatelet. Similar values (Kd 2.4 ± 0.7 × 10−10 mol/l and binding capacity 6.5 ± 1.0 receptors/cell) were obtained by displacement analysis. From kinetic studies the forward and reverse rate constants were 3.1 × 108 mol min−1 1−1 and 3.6 × 10−2/min giving a Kd of 1.2 × 10−10mol/l.
4. The relative binding potencies for angiotensin I1 and analogues were: [Sar1, Thr8]ANC II &gt; ANG II &gt; ANG III &gt; [Sar1, Ala8]ANG II &gt; ANG I.
5. Incubation with an extracellular marker (51Cr-labelled EDTA) demonstrated that binding of angiotensin II to platelets was not due to free fluid endocytosis.
Forearm Arterial Compliance: The Validation of a Plethysmographic Technique for the Measurement of Arterial Compliance
Authors: Fitchett D. , Bouthier J. D. , Simon A. Ch. , Levenson J. A. , Safar M. E. 
Published: August 2015

1. Arterial compliance was determined in eight normal subjects and 23 patients with hypertension and vascular disease by two independent techniques: (a) with a plethysmographic strain gauge (to measure pulsatile forearm volume changes as representing intra-arterial volume changes) and an automated sphygmomanometric system (to measure pulse pressure) and (b) calculation from the local pulse wave velocity and dimension of the brachial artery measured by pulsed wave Doppler ultrasound.
2. Arterial compliance measured both by the plethysmographic technique and calculated from the pulse wave velocity was reduced in subjects with hypertension and vascular disease as compared with normal subjects.
3. The regression equation between the compliance determined by the plethysmographic technique (x) and that calculated (y) from the pulse wave velocity and brachial arterial diameter was y = 3.35x + 1.53, r = 0.77, P &lt; 0.001. The good correlation appears to validate the plethysmographic technique as a method of determining arterial compliance.
Whole Body Cellular and Collagen Nitrogen in Healthy and Wasted Man
Authors: James H. M. , Dabek J. T. , Chettle D. R. , Dykes P. W. , Fremlin J. H. , Hardwicke J. , Thomas B. J. , Vartsky D. 
Published: August 2015

1. The classical literature shows that wasting of body protein takes place mainly from the cellular compartment leaving high proportions of extracellular collagen. Whole body nitrogen (WBN) is proportional to whole body protein (cellular + extracellular) while whole body potassium (WBK) is almost entirely intracellular. WBK might be an adequate index of cellular wasting.
2. WBN was measured by neutron activation and WBK by counting 40K in 29 healthy males and 131 male and female patients with wide ranges of body composition.
3. Our wasted patients with Crohn's disease or ulcerative colitis, had higher WBN/WBK ratios than matched healthy controls and the difference between the two groups was in the cellular ratio (23.6 mol of N/mol of K, 0.33 g of N/mmol of K, 3 mmol of K/g of N). A multiple regression model for all the subjects represented cellular nitrogen by a term in WBK and extracellular nitrogen by simple anthropometric measurements. The partial regression coefficient of WBN on WBK was 22.6 ± 1.1 (se) mol of N/mol of K; this was also similar to the cellular ratio.
4. Our results were compatible with extracellular protein (mainly collagen, which is 35% of normal whole body protein) remaining resistant to wasting even when severe loss of cellular protein occurs. The high ratios of WBN/WBK in wasted patients can be explained by this disproportionate wasting of cellular substances and they do not imply alterations in the cellular N/K ratio.
5. We suggested that the stable ratio of WBK to cellular protein makes it an effective index of cellular wasting. The resistance of collagen to wasting and the preponderance of extracellular mass in the fat-free mass of wasted subjects, make WBN and fat-free mass unreliable guides to the extent of wasting.
Effect of Intraluminal Hydrocortisone on Solute and Water Absorption in the Human Jejunum
Authors: Crake T. , Crisp A. J. , Shearing M. , Record C. O. , Sandle G. I. 
Published: August 2015

1. To compare the effects of intravenous and intraluminal hydrocortisone on jejunal transport, the proximal jejunum was perfused with glucose (28 mmol/l) in saline in two groups of normal subjects.
2. In the first group of seven subjects, compared with the control period results there were no changes in sodium, water and glucose absorption during the intravenous administration of hydrocortisone. In contrast, intraluminal hydrocortisone (100 mg/l) increased sodium, water and glucose absorption by 169%, 223% and 81% respectively (P &lt; 0.001 in each case) above the control values, when peripheral plasma cortisol levels were similar to those achieved with intravenous hydrocortisone.
3. In the second group of three subjects, intraluminal hydrocortisone (10 mg/l and 30 mg/l), followed by an intravenous infusion of hydrocortisone, had no effects on sodium, water and glucose absorption.
4. In a third group of six normal subjects perfused with fructose (28 mmol/l) in saline and bicarbonate (28 mmol/l) in saline intraluminal hydrocortisone (100 mg/l) had no effect on solute and water absorption.
5. These results suggest that intraluminal hydrocortisone stimulates glucose-coupled sodium transport by exerting a topical effect on the apical membrane of the jejunal mucosa.
The Relationship between Human Adipocyte and Monocyte Insulin Binding
Authors: Taylor Roy , Proctor Steven J. , James Oliver , Clark Frederick , Alberti K. George M. M. 
Published: August 2015

1. The assumption that insulin binding to monocytes reflects that of insulin binding to adipocytes has been examined.
2. In normal, diabetic, thyrotoxic and cirrhotic subjects no correlation was observed between monocyte and adipocyte insulin binding.
3. Extrapolation is not justified from monocyte binding data to conclusions about insulin-sensitive tissues.
The effect of Fasting and Hypocaloric Diets on the Functional and Metabolic Characteristics of rat Gastrocnemius Muscle
Authors: Russell David McR. , Atwood Harold L. , Whittaker J. Scott , Itakura Takeo , Walker Paul M. , Mickle Donald A. G. , Jeejeebhoy Khursheed N. 
Published: August 2015

1. Previous observations have shown that in human subjects with malnutrition and after prolonged fasting, there are characteristic changes in the force-frequency response, relaxation rate and power of muscle during a 30 s stimulus (fatigue). In order to characterize these findings under carefully controlled conditions, in different types of muscle and to correlate them with changes in muscle structure, composition and biochemical status, we developed an animal model in rats.
2. In this model, nutrient restriction, both after an acute fast and after chronic hypocaloric feeding, resulted in: (a) loss of force during high frequency stimulation but preservation of contraction-relaxation characteristics during low frequency stimulation; (b) slower muscle relaxation rate at high frequency stimulation; (c) increased muscle fatiguability at high frequency stimulation.
3. Measurements of muscle enzymes showed that acute fasting resulted in a reduced content of glycolytic enzymes, but preservation of oxidative enzymes, while chronic hypocaloric dieting resulted in a reduction in both classes of enzyme.
4. There was no significant change in ATP, AMP or energy charge, or in intracellular sodium, potassium and magnesium levels. Creatine phosphate was normal in acutely fasted animals but low in those fed hypocalorically. By contrast, increased intracellular calcium and ADP levels were seen in both fasted and hypocalorically fed animals. These findings suggest that subtle disturbances of intracellular energy states with altered calcium flux may be of importance in the genesis of muscle dysfunction caused by malnutrition.
Factors affecting Potassium Balance During Frusemide Administration
Authors: Wilcox Christopher S. , Mitch William E. , Kelly Ralph A. , Friedman Paul A. , Souney Paul F. , Rayment Carolyn M. , Meyer Timothy W. , Skorecki Karl L. 
Published: August 2015

1. We investigated the effects of Na+ intake, the renin-angiotensin-aldosterone system and antidiuretic hormone (ADH) on K+ balance during 3 days of frusemide administration to six normal subjects. Subjects received 40 mg of frusemide for 3 days during three different protocols: Na+ intake 270 mmol/day (high salt); Na+ intake 20 mmol/day to stimulate the renin-angiotensin-aldosterone system (low salt); Na+ intake 270 mmol/day plus captopril (25 mg/6 h) to prevent activation of the renin-angiotensin-aldosterone system. In a fourth protocol, a water load was given during high salt intake to prevent ADH release and then frusemide was given.
2. During high salt intake, frusemide increased K+ excretion (UKV) over 3 h, but the loss was counterbalanced by subsequent renal K+ retention so that daily K+ balance was neutral.
3. During low salt intake, the magnitude of the acute kaliuresis following the first dose of frusemide and the slope of the linear relationship between UKV and the log of frusemide excretion were increased compared with that found during the high salt intake. In addition, low salt intake abolished the compensatory renal retention of K+ after frusemide and cumulative K+ balance over 3 days of diuretic administration was uniformly negative (−86 ± 7 mmol/3 days; P &lt; 0.001).
4. Captopril abolished the rise in plasma aldosterone concentration induced by frusemide. The acute kaliuresis after frusemide was unchanged compared with that observed during high salt intake. The compensatory reduction in UKV occurring after the diuretic was slightly potentiated. In fact, captopril given without the diuretic induced a small positive K+ balance.
5. When a water load was given concurrently with frusemide, the acute kaliuresis was &gt;30% lower compared with that seen with frusemide alone, even though the natriuretic response was unchanged.
6. We conclude that: (a) K+ balance is maintained when frusemide is given during liberal Na+ intake because acute K+ losses are offset by subsequent renal K+ retention; (b) this compensatory K+ retention can be inhibited by aldosterone release which could account for the negative K+ balance seen during salt restriction; (c) the short-term kaliuretic response to frusemide is augmented by release of both ADH and aldosterone whereas changes in K+ balance over 3 days of frusemide are dependent on plasma aldosterone concentration.
Changes in Gastric Emptying Rates with Age
Authors: Horowitz Michael , Maddern Guy J. , Chatterton Barry E. , Collins Peter J. , Harding Philip E. , Shearman David J. C. 
Published: August 2015

1. A dual isotope technique which measures simultaneously the emptying of solids and liquids by the stomach was used to study gastric emptying in 35 subjects in the age range 21-84 years, who were all fit, mobile volunteers and were not taking any drugs.
2. Solid and liquid emptying were significantly slower in older subjects, but this finding is unlikely to be of clinical significance because the changes were small and emptying rates were usually within the normal range for younger subjects.
Inhibitor Binding Assay of rat Serum Angiotensin Converting Enzyme
Authors: Tikkanen Ilkka , Fyhrquist Frej , Forslund Terje 
Published: August 2015

1. Based on a specific binding of labelled inhibitor to the enzyme active centre, a new principle of enzyme assay, inhibitor binding assay (IBA), was developed and applied to measurement of rat serum angiotensin converting enzyme (ACE).
2. Serum diluted 1:50 was incubated with 125I-labelled ACE inhibitor, 351A, at pH 7.0, 37°C, for 2 h. Inhibitor bound to ACE was separated with coated charcoal and results were calculated from a standard curve.
3. The advantages offered by the novel inhibitor binding assay include simplicity, specificity, absence of interference by other enzymes or immunological cross-reactions, and great sensitivity enabling measurement of ACE in concentrations less than 0.1 units/ml.
4. This principle of enzyme assay will not only have potential new applications for research involving ACE but may also be extended to other enzymes.
Ascending Brain-Stem Noradrenergic Pathways Modulate the Renin Response to Haemorrhage
Authors: Lightman S. L. , Todd K. , Everitt B. J. , Brown M. J. , Causon R. C. 
Published: August 2015

1. Ventral noradrenergic projections (VNAB) from lateral tegmental (A1, A2) and dorsal noradrenergic projections (DNAB) from the coeruleal (A6) as well as A1 cell groups in the brain-stem of the rat were lesioned by intracerebral injection of 6-hydroxydopamine.
2. A marked increase in plasma renin activity and adrenaline concentrations followed haemorrhage (0.5 ml/100 g body weight) in the sham-operated rats. VNAB-lesioned rats showed a similar response to the sham-operated controls, but in DNAB-lesioned animals the rise of plasma renin was markedly attenuated.
The Basal Levels of Active and Inactive Plasma Renin Concentration in Infancy and Childhood
Authors: Fiselier T. , Derkx F. , Monnens L. , Van Munster P. , Peer P. , Schalekamp M. 
Published: August 2015

1. Basal plasma renin activity, active and inactive plasma renin concentration were measured in 89 healthy recumbent children aged between 1 week and 16 years.
2. A significant (P&lt;0.001) age-related decrease for active (r = −0.60), inactive (r = −0.59) and total renin concentration (r = −0.66) was observed.
3. After correction for the influence of age, active renin concentration correlated with plasma renin activity (r = 0.81), but not with inactive renin concentration (r = 0.18).
4. The proportions of active and inactive renin were not related to age, and the overall percentage of inactive renin was 79%.
Differences in the Effect of Mediastinal Radiotherapy on Lung Function and the Ventilatory Response to Exercise
Authors: Jones P. W. , Al-Hillawi A. , Wakefield J. M. , Johnson N. McI. , Jelliffe A. M. 
Published: August 2015

1. To examine the effect of lung inflammation on lung volumes and carbon monoxide transfer and their relationship to the ventilatory and gas exchange responses to exercise, a prospective study was performed in patients having Hodgkin's disease, with no evidence of intrathoracic involvement, who received prophylactic mantle-field radiotherapy to the chest.
2. From 6 weeks to 6 months from the start of therapy, vital capacity (FVC) was on average 10.4% lower than during the baseline period and the total transfer of carbon monoxide (TLCO) was 10.5% lower. Minute ventilation (V̇E) at any given work load during an incremental exercise test was on average 10.5% higher than baseline. The stimulation of ventilation after radiotherapy was present at all work rates, but greater at high work rates.
3. A number of other changes in the ventilatory and gas exchange responses to exercise were also seen. Most of these lay outside the range of variability observed in a group of normal subjects tested concurrently with the patients.
4. There was a poor, but statistically significant, positive correlation between reduction in FVC and increase in V̇E after radiotherapy and between reduction in carbon monoxide transfer and increase in V̇E.
5. A significant correlation between reduction in FVC and change in respiratory rate was also seen after radiotherapy, together with a significant inverse correlation between increase in respiratory rate and fall in tidal volume.
6. The ratio of V̇E to oxygen consumption, the ventilatory equivalent for oxygen, was calculated at each work rate. There was a negative correlation between the mean increase in this parameter, averaged over all work rates, and the reduction in FVC and TLCO, i.e. the greatest stimulation of breathing relative to metabolic demand occurred in those patients with the least change in lung volume.
7. In the period after 6 months lung volumes and carbon monoxide transfer fell further, or remained the same, but V̇E returned towards pretreatment levels.
8. It is suggested that changes in ventilatory response to work after lung inflammation, are the result of a balance between an increased drive to breathe and changes in the mechanical properties of the lungs.
Correlation between Platelet Behaviour and Cold-Induced Vasoconstriction in Man, and the Effects of Epoprostenol Infusion
Authors: Cowley A. J. , Stainer Karen , Cockbill S. , Heptinstall S. 
Published: August 2015

1. Drugs that cause vasodilatation tend to inhibit platelet behaviour whereas compounds that cause vasoconstriction stimulate platelet behaviour. Thus there appears to be a similarity between platelet behaviour and vascular tone. To investigate this relationship we have compared the maximum vasoconstrictor response in the forearm induced by cold stimulation with some aspects of platelet behaviour.
2. In 26 normal volunteers there was a close correlation between the maximum vasoconstrictor response to cold and the threshold concentration of sodium arachidonate that was needed to induce platelets from each individual to aggregate and to undergo a release reaction (r = 0.774, P&lt;0.001).
3. Infusion of epoprostenol (prostacyclin) in five volunteers altered both the maximum vasoconstrictor response to cold and the threshold concentration of sodium arachidonate needed to induce platelet aggregation in a manner parallel to this relationship.