bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective dietary potassium depletion and acid-base equilibrium in the rat
Authors: Girard Pierre , Brun-Pascaud Monique , Paillard Michel 
Published: August 2015

1. K+ depletion of two kinds was induced in two groups of rats by selective dietary restriction for up to 5 weeks. Complete metabolic studies for H+, K+, Na+ and Cl− were carried out daily during weeks 1, 3 and 5.
2. In control rats of group A (receiving K+ with sodium chloride), plasma pH (7.47) and HCO−3(25 mmol/l), as well TA (titratable acid) —- HCO−3 and NH+4 urinary excretion rates, were stable, while balances were nil for K+ and slightly positive for Cl−. In K+-deprived rats of group A receiving sodium chloride, a progressive metabolic alkalosis developed (plasma pH reached 7.57 and HCO−3 35.8 mmol/l by 5 weeks), and TA - HCO−3 and NH+4 urinary excretion rates were not different from controls. Plasma K+ fell progressively from 4.20 to 2.20 mmol/l, with negative K+ balance. Balances for Na+ and H2O were highly positive and plasma renin activity and aldosterone decreased by week 5. Hypochloraemia developed with positive Cl− balance.
3. In control rats of group B (receiving K+ with neutral sodium phosphate), a slight metabolic alkalosis developed, and TA - HCO−3 excretion rate was increased compared with control rats of group A. Balances were slightly negative for K+ and Cl−. In K+-deprived rats of group B receiving neutral sodium phosphate, a profound metabolic alkalosis developed (plasma pH reached 7.60 and HCO−3 42.6 mmol/l by 5 weeks), and TA-HCO−3 and NH+4 excretion rates were at no time different from those of control rats of group B. Plasma K+ fell progressively from 4.25 to 2.30 mmol/l, and K+ balance was more negative than that in control rats of group B. Hypochloraemia developed with a negative Cl− balance.
4. In both K+-restricted groups, a linear negative correlation was observed between plasma HCO−3 (or pH) and plasma K+. These results suggest that metabolic alkalosis does occur in sustained selective K+-depletion in rats. Metabolic alkalosis could be generated essentially by net transfer of H+ from extracellular fluid (ECF) into cells, probably in exchange for K+ in the reverse direction. Metabolic alkalosis could be maintained by an increase in tubular reabsorption of filtered HCO−3, probably via an enhanced Na+/H+ exchange in the proximal tubule in sodium chloride-loaded rats, which may account for the ECF volume expansion with low plasma renin activity and aldosterone, and via an enhanced Cl−/HCO−3 exchange in distal nephron in sodium phosphate-loaded rats.
An adenylate cyclase bioassay for parathyroid hormone: some clinical experiences
Authors: Seshadri M. S. , Chan Y. L. , Wilkinson M. R. , Mason R. S. , Posen S. 
Published: August 2015

1. An adenylate cyclase bioassay for parathyroid hormone (PTH) was evaluated in peripheral sera of ten normal subjects, 15 patients with various types of hypoparathyroidism, nine patients with malignancy-associated hypercalcaemia and 60 patients with primary or secondary hyperparathyroidism. The lower limit of detectability was 150 pg/ml in terms of synthetic human PTH (1-34).
2. PTH-like bioactivity was not detected in normal subjects, in patients with surgical hypoparathyroidism, in patients with idiopathic hypoparathyroidism or in patients with malignancy-associated hypercalcaemia. Serum from one untreated pseudohypoparathyroid patient consistently contained PTH-like bioactivity.
3. Bioactivity was detected in sera from 50% of patients with primary or secondary hyperparathyroidism. In two patients with secondary hyperparathyroidism calcium infusions suppressed this activity within 5 min.
4. Both in primary and in secondary hyperparathyroidism there was a significant positive correlation between levels of PTH-like bioactivity, PTH immunoreactivity and the histological severity of the disease.
Arterial oxygen desaturation during treadmill and bicycle exercise in patients with chronic obstructive airways disease
Authors: Cockcroft A. , Beaumont A. , Adams L. , Guz A. 
Published: August 2015

1. Nine men with severe chronic obstructive airways disease (COAD), known to desaturate on exercise, performed a 6 min self-paced walk on a treadmill, followed by a bicycle exercise with workloads adjusted to mimic the oxygen consumption achieved on the treadmill. During both exercises, ventilation, oxygen consumption, carbon dioxide production, Pao2, Paco2, pH and arterial lactate were measured and subjective breathlessness recorded.
2. A reasonable match of oxygen consumption between the two exercises was achieved. In all subjects Pao2 fell to a lower level during treadmill compared with bicycle exercise. Ventilation, carbon dioxide production and arterial lactate were higher during bicycle exercise. Subjective breathlessness was greater during bicycle exercise, in proportion to the higher ventilation on the bicycle.
3. The greater anaerobiosis occurring on the bicycle led to acidosis and an increased ventilation, minimizing the exercise fall in Pao2.
4. Bicycle testing may seriously underestimate exercise desaturation occurring during level walking in patients with severe COAD.
Effect of prolonged bile duct obstruction in the rat on hepatic transport of bilirubin
Authors: Kountouras Jannis , Scheuer Peter J. , Billing Barbara H. 
Published: August 2015

1. In order to investigate the effect of extra-hepatic biliary obstruction on bilirubin transport, bile flow was re-established after 5, 10, 15 and 28 days when the mean (±sem) plasma bilirubin concentrations of the four groups of five rats were 226 ± 17.9, 201 ± 22.4, 178 ± 8.1 and 145 ± 3.8 μmol/l, respectively.
2. After 12 h of bile drainage in the conscious animal, the mean plasma bilirubin concentrations of the four groups had decreased by 88, 86, 73 and 46%, respectively.
3. The bile flow rate increased with the duration of the obstruction and was maximal in the 28 day obstructed rats, although the bilirubin output in these animals was significantly less than in the other groups.
4. Histological evidence of biliary obstruction was apparent in the livers of the 5 and 10 day obstructed animals. After 15 days of obstruction cirrhosis developed.
5. In conclusion, the disposal of endogenous bilirubin in the bile duct obstructed rat appears to be influenced by the development of cirrhosis.
Sodium pentosan polysulphate as a polyanionic inhibitor of calcium oxalate crystallization in vitro and in vivo
Authors: Norman R. W. , Scurr D. S. , Robertson W. G. , Peacock M. 
Published: August 2015

1. Studies in vitro showed that sodium pentosan polysulphate (SPP) is an active inhibitor of calcium oxalate crystal growth and agglomeration and that it acts by increasing the negative zeta potential on the surface of calcium oxalate crystals.
2. Oral administration to human subjects resulted in an increase in the negative zeta potential, which is consistent with an increase in the polyanionic inhibitory activity of urine. SPP may offer a novel approach to the medical management of recurrent calcium oxalate stone disease.
Calmodulin levels in hypertensive rats
Authors: Higaki J. , Ogihara T. , Kumahara Y. , Bravo E. L. 
Published: August 2015

1. Intracellular calmodulin levels were measured by direct radioimmunoassay in spontaneously hypertensive rats (SHR) and Wistar—Kyoto rats (WKY).
2. Decreased calmodulin levels were demonstrated in the brain, heart, aorta and kidney of spontaneously hypertensive rats compared with those in Wistar—Kyoto rats.
3. Calmodulin levels in the brain were also decreased in deoxycorticosterone acetate (DOCA)-salt rats, but not changed significantly in the heart, aorta and kidney compared with those in Wistar—Kyoto rats.
4. These findings suggest that intracellular calcium-dependent regulatory systems are genetically disrupted in spontaneously hypertensive rats, but this is probably not an important factor in the development of hypertension.
Human mast cells recovered by bronchoalveolar lavage: their morphology, histamine release and the effects of sodium cromoglycate
Authors: Flint K. C. , Leung K. B. P. , Pearce F. L. , Hudspith B. N. , Brostoff J. , Johnson N. McI. 
Published: August 2015

1. Mast cells make up between 0.5 and 3% (mean 1.35%) of total cells recovered by bronchoalveolar lavage (BAL).
2. The majority of these cells have the morphological characteristics of mucosal mast cells in that they fail to stain in the alcian blue-safranin reaction after fixation in formol-saline but stain well after fixation in Carnoy's solution. Cells staining with berberine sulphate were seen in only four of the 26 lavages.
3. BAL cells released histamine in response to anti-human immunoglobulin E (IgE) in a dose-dependent manner that was optimal at a dilution of anti-IgE of 1:100. Maximum release was obtained by 2 min.
4. Histamine release was completely inhibited by a combination of 2-deoxyglucose (5 mmol/l) and antimycin A (1 μmol/l).
5. Disodium cromoglycate (DSCG) significantly inhibited this histamine release at 1 mmol/l (P&lt;0.02), 100 μmol/l (P&lt;0.002) and 10 μmol/l (P&lt;0.003), with maximum inhibition of 50.1% at 10 μmol/l.
Effects of dietary fish oil supplementation on the fatty acid composition of the human platelet membrane: demonstration of selectivity in the incorporation of eicosapentaenoic acid into membrane phospholipid pools
Authors: Galloway John H. , Cartwright Ian J. , Woodcock Barrie E. , Greaves Michael , Graham R. , Russell G. , Preston F. Eric 
Published: August 2015

1. The fatty acid composition of membrane phospholipids of stimulated and unstimulated platelets was studied in six normal volunteers given a daily dietary supplement of a fish oil rich in eicosapentaenoic acid (EPA) for 4 weeks. The supplement was equivalent to 1.8 g of EPA daily. Thromboxane synthesis and platelet aggregation responses to sodium arachidonate, thrombin and the ionophore A23187 were also investigated.
2. A marked increase in the relative EPA content of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was noted after 2 and 4 weeks fish oil supplementation. However, there was no incorporation into phosphatidylinositol (PI) or phosphatidylserine (PS). The relative arachidonic acid (AA) content of PC and PE was significantly reduced at 2 and 4 weeks but that of PI and PS remained unchanged. Significant reductions in the relative linoleic acid content of total phospholipids, PC and PE were also noted.
3. Stimulation of platelets obtained after 4 weeks fish oil supplementation by thrombin and A23187 was associated with a marked reduction in the AA content of PI and a minor reduction in that of PE. There was no change in the relative proportions of EPA in PI, PS, PC or PE after stimulation. Throughout the study there were no significant changes in platelet aggregation responses or in platelet thromboxane production.
4. Our results indicate that the incorporation of EPA into the platelet membrane phospholipids is selective and that if PI is the major source of AA for platelet prostaglandin biosynthesis then the reported beneficial effects of EPA on haemostasis cannot be explained on the basis of its incorporation into and mobilization from the platelet membrane phospholipid pool.
Mass and composition of the fat-free tissues of patients with weight-loss
Authors: Burkinshaw L. , Morgan D. B. 
Published: August 2015

1. An estimate of the mass of fat-free tissue in the body can be calculated from body weight and skinfold thickness; this estimate is called the ‘fat-free mass'. Total body potassium and nitrogen are alternative estimates. Factor analysis of data for healthy subjects has defined relationships between the true values of these three quantities and estimated the random component of the variance of each, i.e. the component independent of variations in the mass of fat-free tissue. The results indicated that all three were reliable measures of the mass of fat-free tissue. However, it is not known whether these findings are valid for patients who have lost weight.
2. We have measured the same three quantities in 104 wasted patients with heart disease or disorders of the gastrointestinal tract. The patients’ mean values were significantly less than corresponding values for healthy volunteers. The patients had a mean ratio of total body nitrogen to fat-free mass similar to that of healthy subjects, but lower mean ratios of potassium to fat-free mass and nitrogen. These findings suggest that the potassium content of the patients’ fat-free tissues was abnormally low.
3. Factor analysis of the patients’ data gave relationships between the true values of the three quantities similar to those for healthy subjects; however, total body potassium was 100-300 mmol lower in patients than in healthy subjects with the same fat-free mass or total body nitrogen.
4. Factor analysis also showed that the random components of variance of fat-free mass and total body nitrogen were similar to those in healthy subjects. Therefore, in the patients as in healthy subjects, fat-free mass was as valid a measure of fat-free tissue as the more complex measurement of total body nitrogen. The random component of total body potassium was twice as big as in healthy subjects; however, it formed no greater a proportion of total variance than did the random components of the other two quantities.
5. Total body nitrogen, and hence body protein, could be estimated from measured fat-free mass with a standard error of approximately 136 g (compared with 139 g for healthy individuals), and from total body potassium with a standard error of 129 g (compared with 91 g in healthy subjects).
Impaired baroreflex sensitivity in the aetiology of salt hypertension in the rabbit
Authors: Weinstock Marta , Schorer-Apelbaum Donna 
Published: August 2015

1. This study was designed to see whether normotensive rabbits with an impairment in baroreflex control of heart rate due to genetic factors are more susceptible to high salt or deoxycorticosterone acetate (DOCA)-salt hypertension. The baroreflex sensitivity of 27 conscious rabbits was assessed by both the ‘steady-state’ and ‘ramp’ methods in response to injections of phenylephrine (2.5-30 μg/kg).
2. Animals with differing baroreflex sensitivities were then given 4 weeks treatment with 8% NaCl and 1.3% KCl in food (treatment A), or DOCA (25 mg pellet, subcutaneously) with 0.5% NaCl and 0.13% KCl in drinking water (treatment B). A third group were maintained on a regular diet of food and water (controls).
3. A highly significant negative correlation (r = 0.91, P &lt; 0.01) was found between the increase in mean arterial pressure (MAP) produced either by treatment A or treatment B and the baroreflex sensitivity before treatment. There was no significant correlation between the increase in MAP and (a) initial MAP; (b) increase in body weight; (c) serum K+ after treatment; (d) baroreflex sensitivity before treatment, when assessed by the ‘ramp’ method.
4. It is concluded that animals with low baroreflex sensitivity due to a reduced ability to suppress cardiac sympathetic activity in response to a pressor stimulus, are more likely to develop hypertension as a result of salt loading. It remains to be determined whether the susceptibility to salt of rabbits with lower baroreflex sensitivity is also associated with a difference in the renal excretion of Na+ ions.
Salt-induced hypertension in the ‘Sabra’ rat strain: influence of nifedipine treatment
Authors: Garthoff Bernward , Ebsen Wolfgang , Luckhaus Georg , Kazda Stanislav , Ben-Ishay Drori 
Published: August 2015

1. The effects of chronic dietary salt-loading and nifedipine therapy on hypertension-prone (SBH), -resistant (SBN) and parental (SB) Sabra rats were investigated. Salt diet for 12 weeks resulted in a sustained hypertension and heart hypertrophy only in SBH.
2. Nifedipine therapy (300 p.p.m. = 300 mg/kg of food) introduced after week 7 on a salt diet, achieved small changes in salt-loaded SBN and SB rats, but resulted in a marked decrease in blood pressure in SBH rats within 1 week and in a regression of cardiac hypertrophy.
3. Plasma renin activity rose slightly in nifedipine treated SB and SBN rats, but decreased significantly in treated SBH rats.
4. Histopathological investigations revealed hypertensive vasculopathy in three out of nine untreated SBH rats, whereas there were no morphological changes in the treated rats.
Cation transport functions in vitro in patients with untreated essential hypertension: a comparison of erythrocytes and leucocytes
Authors: Boon N. A. , Harper C. , Aronson J. K. , Grahame-Smith D. G. 
Published: August 2015

1. We have measured intracellular sodium concentrations and specific 3H-labelled glycoside binding characteristics in the erythrocytes and leucocytes of patients with untreated essential hypertension, and have compared the results with those in well-matched normotensive control subjects.
2. Intracellular sodium concentrations were increased in the leucocytes, but not in the erythrocytes, of patients with untreated essential hypertension.
3. There were no differences in the 3H-labelled glycoside binding characteristics of either the erythrocytes or the leucocytes of hypertensive and normotensive subjects.
4. There was no difference in the ability of plasma samples from hypertensive and normotensive subjects to inhibit the binding of [3H]-ouabain to intact leucocytes from normotensive subjects.
5. These findings are not consistent with the presence of increased concentrations of a substance which behaves like a cardiac glycoside in the circulation of patients with untreated essential hypertension.
Adrenaline and ion flux in isolated human leucocytes
Authors: Baron D. N. , Green Rachel J. , Khan F. A. 
Published: August 2015

1. Hypokalaemia may be produced in man by intravenous adrenaline infusion, or as a result of pathological disturbances which have led to a high plasma adrenaline concentration.
2. With isolated human leucocytes used as a cellular model, adrenaline at concentrations at and above 9 nmol/l increases the influx of rubidium (a model for potassium flux) into cells, with a simultaneous efflux of sodium. There is no effect on Na+, K+-ATPase activity in lysed leucocytes.
3. Use of the adrenoceptor blockers timolol and atenolol shows that the demonstrated effect of adrenaline on coupled active transport of ions is mediated by β2-adrenoceptors.
Human Tamm-Horsfall glycoprotein: urinary and plasma levels in normal subjects and patients with renal disease determined by a fully validated radioimmunoassay
Authors: Thornley Carolyn , Dawnay Anne , Cattell W. R. 
Published: August 2015

1. A recently developed, simple and sensitive radioimmunoassay has been used to examine 24 h excretion and plasma levels of Tamm-Horsfall glycoprotein (THG) in normal subjects, stone formers and patients with stable chronic renal disease.
2. In normal subjects THG excretion ranged from 22 to 66 mg/24 h, with no sex difference and no correlation with creatinine clearance or body surface area. There was no correlation between 24 h THG excretion and urine volume, pH or osmolality, excretion of Na+, K+ or Ca2+ or free-water clearance. There was a small significant correlation between plasma THG concentration and urinary THG excretion.
3. A good correlation was obtained between the THG/creatinine ratio in 24 h and random samples. This made possible the use of random samples to establish a reference range for THG excretion of 0.15-0.50 μg/ml of creatinine clearance which did not depend on sex or age.
4. The excretion rate of THG in stone formers was generally within the reference range. It was not significantly different in those who were hypercalciuric or in those taking thiazides.
5. In patients with chronic renal disease there was a good correlation between 24 hTHG excretion, plasma THG concentration and creatinine clearance. The range of excretion of THG per ml of creatinine clearance was greater than in normal subjects, independent of the type of renal disease and unrelated to proteinuria.
6. In patients with glomerulonephritis the excretion of THG per ml of creatinine clearance was significantly higher in those with well-preserved tubules compared with those with tubular atrophy.
Antidiuretic hormone response to volume depletion in diabetic patients with cardiac autonomic dysfunction
Authors: Grimaldi André , Pruszczynski Wojciech , Thervet Francis , Ardaillou Raymond 
Published: August 2015

1. Thirty-three insulin-dependent diabetic patients were separated into two groups from the results of three different tests for cardiac vagal neuropathy: heart rate response to deep breathing, Valsalva manoeuvre and heart rate response to postural change. Seventeen patients were considered as without ('intact’ patients) and 16 as with ('denervated’ patients) cardiac autonomic dysfunction. One patient with a transplanted heart was also studied.
2. Plasma antidiuretic hormone (ADH), plasma aldosterone and plasma renin activity (PRA) were measured immediately before and 60 min after intravenous administration of frusemide and passage from lying to standing. The kinetics of hormonal responses were analysed more precisely (five blood collections) in six patients of each group who were studied again. Heart rate and blood pressure were recorded before each blood collection.
3. Volume depletion estimated from the rise in plasma protein (+ 11.9 and + 12.2% in ‘denervated’ and ‘intact’ patients respectively) and heart rate response (+ 10.6 and + 14.7%) were similar in both groups. Mean blood pressure was unchanged in the ‘intact’ patients whereas it fell in the ‘denervated’ patients (−13.5%). PRA (+ 161.5 and + 231.2% in ‘denervated’ and ‘intact’ patients respectively) and plasma aldosterone (+ 318.2 and 279%) increased in both groups whereas plasma ADH was stimulated only in ‘intact’ patients (+ 55.3%). The failure of ADH to respond significantly to the volume stimulus in ‘denervated’ patients was confirmed by the results of the time-course study. Plasma ADH remained at the same levels in ‘denervated’ patients whereas it increased significantly (+ 82.4%) in ‘intact’ patients. There was no ADH response in the transplanted patient.
4. These results suggest that, in humans, cardiac receptors and vagal pathways play a role in ADH response to volume depletion.
Superoxide radicals, immunodeficiency and xanthine oxidase activity: man is not a mouse!
Authors: Simmonds H. A. , Goday A. , Morris G. S. 
Published: August 2015

1. The importance of intact adenosine deaminase (ADA) activity in the generation of superoxide anion by xanthine oxidase has been disputed in studies using human neutrophils or mouse macrophages. The latter demonstrated a positive correlation between ADA activity and superoxide production during phagocytosis. The immunodeficiency in inherited ADA deficiency was related to a defect in this process.
2. Since there is considerable interspecies variation in the tissue distribution of xanthine oxidase, the metabolism of [8-14C]deoxyadenosine (dAR), the toxic metabolite which accumulates in inherited ADA deficiency, was investigated in human peritoneal macrophages.
3. Evaluation of the distribution of radiolabel in both cell and medium demonstrated that human macrophages with intact ADA metabolize dAR under physiological conditions to deoxyinosine and hypoxanthine exclusively. The hypoxanthine is further metabolized within the cell to ATP and GTP, via IMP.
4. No xanthine or uric acid could be detected, confirming that in human macrophages xanthine oxidase activity is insignificant, as it is in most other human cells and tissues, except liver and intestinal mucosa. Thus production of superoxide radicals in such cells via this route would be impossible, and consequently unaffected either by ADA deficiency or the xanthine oxidase inhibitor allopurinol.