bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison between short-term Renal Haemodynamic Effects of Propranolol and Nadolol in Essential Hypertension: A Crossover Study
Authors: Danesh Boothur J. Z. , Brunton Joyce , Sumner David J. 
Published: August 2015

1. The effect of 4-6 weeks’ treatment with propranolol and nadolol on effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) was studied, in 14 patients with essential hypertension, in single blind, random and cross-over design.
2. Both drugs caused comparable effective lowering of pulse and blood pressure.
3. When taken as the first drug, propranolol caused significant reduction in ERPF and GFR and a rise in filtration fraction (FF) and renal vascular resistance (RVR), whereas nadolol caused distinct rise in ERPF and a fall in FF and RVR but GFR remained unchanged.
4. These haemodynamic effects were reduced when propranolol was given immediately after the withdrawal of nadolol and were obviated when nadolol followed propranolol therapy. This suggested a carry-over effect of the first drug into the second phase of treatment.
5. We conclude that with short term therapy in essential hypertension, propranolol has a renal vasoconstrictor and nadolol a vasodilator effect.
The Temporal Distribution of the 1α,25-Dihydroxycholecalciferol Receptor in the Rat Jejunal Villus
Authors: Chan S. D. H. , Atkins D. 
Published: August 2015

1. The distribution of the 1α,25-dihydroxycholecalciferol receptor was studied in enterocytes isolated from the upper, mid and lower villus and crypt cells of the jejunum of normal and rachitic rats.
2. In all cell fractions a high-affinity receptor (KD ⋍ 0.07 nmol/l) with a sedimentation coefficient of 3.5S was demonstrated.
3. In normal rats there was a 60% reduction in receptor numbers in crypt cells compared with the mid and upper villous cells.
4. Vitamin D deficiency led to a reduction in receptor numbers in all cell fractions (45% upper villus, 78% crypt cells).
5. The data are compatible with the concept of calcium absorption occurring in the differentiated villous cells and also account for the reduction in absorption in rachitic animals.
Glycogen Metabolism in Psoriatic Epidermis and in Regenerating Epidermis
Authors: Harmon C. S. , Phizackerley P. J. R. 
Published: August 2015

1. The observation that the glycogen content of epidermis from psoriatic lesions and from regenerating wound epithelium is increased has been confirmed by quantitative estimation.
2. In epidermis from psoriatic lesions, although the proportion of glycogen synthase in the I form is only about 5% of the total and similar to control values, total glycogen synthase activity is increased approximately 4-fold and hence glycogen synthase I activity is increased to the same extent. In contrast, total phosphorylase activity is only slightly increased and, since the proportion of the enzyme in the a form is reduced, phosphorylase a activity is similar to control values.
3. In epidermis from psoriatic lesions, the concentration of UDP-glucose is approximately doubled, and the concentrations of fructose 1,6-bisphosphate and of 6-phosphogluconate are increased approximately 5-fold. It is concluded that rates of glycogen synthesis, of glycolysis and of the pentose phosphate pathway are all enhanced in vivo and in consequence the rate of glucose uptake by psoriatic epidermis must be increased.
4. In the non-involved epidermis of psoriatic patients the glycogen content is within normal limits, and although total glycogen synthase activity is increased the ratio of glycogen synthase I to phosphorylase a is maintained at normal levels by the appropriate phosphorylation of both enzymes.
5. In regenerating wound epithelium in the pig, the changes in enzyme activity and in metabolite concentration closely resemble those found in epithelium from psoriatic lesions except that in wound epithelium the proportion of phosphorylase in the a form is increased relative to normal epithelium.
The Regulatory Roles of Liver and Kidney in Cobalamin (Vitamin B12) Metabolism in the Rat: the Uptake and Intracellular Binding of Cobalamin and the Activity of the Cobalamin-Dependent Enzymes in Response to Varying Cobalamin Supply
Authors: Scott J. S. D. , Treston A. M. , Bowman E. P. W. , Owens J. A. , Cooksley W. G. E. 
Published: August 2015

1. To examine possible regulatory roles of liver and kidney in cobalamin metabolism, specific activities of the two cobalamin-dependent enzymes, uptake in vivo of cyano[57Co]cobalamin ([57Co]CNCbl) and the binding of [57Co]Cbl to intracellular proteins were measured in normal, cobalamin-loaded and cobalamin-deficient rats. Cobalamin deficiency and cobalamin loading produced greater changes in cobalamin concentration in the kidney than in the liver.
2. Although cobalamin deficiency resulted in a decrease in total methylmalonyl-coenzyme A mutase (methylmalonyl-CoA mutase) in both organs, cobalamin loading had no effect. Neither deficiency nor loading altered total methyltransferase activity. The holoenzyme activities of both enzymes correlated with changes in tissue cobalamin levels.
3. Uptake of [57Co]Cbl indicated that the kidney, in contrast to the liver, increased its uptake during loading and reduced it during deficiency, suggesting a possible regulatory role for this organ.
4. In the normal rat, 24 h after injection of [57Co]CNCbl, 0.3% of the administered [57Co]Cbl was present in the liver as free cobalamin. By contrast, in the kidney, over 13% of the [57Co]Cbl was present in the free form. During deficiency free renal [57Co]Cbl was reduced to 0.6% of the administered [57Co]Cbl whereas in cobalamin-loaded rats it was increased to more than 27%.
5. It is concluded that alterations in tissue cobalamin levels resulting from differences in cobalamin supply are due to changes in the large pool of free cobalamin present in the kidney and not to changes in the intracellular binding.
Glucocorticoid Inhibition of Mineralocorticoid Action in the Rat
Authors: Kenyon C. J. , Saccoccio N. A. , Morris D. J. 
Published: August 2015

1. The mineralocorticoid activity of corticosterone based on acute changes in urinary Na+/K+ ratios in adrenalectomized rats was 1000 times less than that of aldosterone. However, corticosterone had only kaliuretic actions whereas aldosterone had both antinatriuretic and kaliuretic properties. Corticosterone inhibited the antinatriuretic actions of aldosterone.
2. Adrenalectomized rats infused continuously with a physiological dose of corticosterone (1 mg/day) were 5 times less sensitive to the antinatriuretic and 25 times less sensitive to the kaliuretic actions of aldosterone when administered acutely than were control adrenalectomized rats.
3. The long term effects of infusions of physiological doses of aldosterone and corticosterone were assessed in adrenalectomized rats maintained in metabolic cages. Aldosterone lowered plasma renin activity and reduced fluid (0.3% NaCl) intake; these effects were diminished when aldosterone and corticosterone were infused simultaneously. Plasma renin activity and fluid intake were correlated in long term infusion experiments. Both hormones had hypokalaemic effects but these were not additive. Corticosterone, but not aldosterone, increased systolic blood pressure and plasma sodium levels.
4. We conclude that glucocorticoid effects on water and electrolyte metabolism are different from those of mineralocorticoids, that glucocorticoids may antagonize mineralocorticoid effects and that interactions between mineralocorticoids and glucocorticoids may be important in long term blood pressure regulation.
Enzymatic Activity of Renin in Plasma of Normal and Uraemic Subjects
Authors: Kotchen Theodore A. , Guyenne Tam T. , Corvol Pierre , Menard Joel 
Published: August 2015

1. Plasma renin reactivity (PRR) is the rate of angiotensin I production after addition of renin to plasma, minus endogenous renin activity. PRR is increased in plasma of patients with renal failure compared with that of normal subjects. The present study was carried out to determine if increased PRR in uraemic plasma is related to differences of endogenous active or inactive renin, endogenous renin substrate, or pH of the incubation in vitro.
2. PRR in plasma of ten uraemic patients was greater (P&lt;0.02) than that in plasma of ten normal subjects in incubations carried out at pH 7.4 and 5.7.
3. Increased PRR was not accounted for by differences of endogenous active and inactive renin activity.
4. After addition of renin, renin concentration (measured by direct radioimmunoassay) did not differ in normal and uraemic plasma.
5. Renin substrate concentration, measured both indirectly and by direct radioimmunoassay, also did not differ in normal and uraemic plasma.
6. Increased PRR in uraemic plasma is not related to alterations of renin or renin substrate concentrations. These observations are consistent with our earlier hypothesis that there is a deficiency of a renin inhibitor in uraemic plasma.
Angiotensin Converting Enzyme Response to Hypoxia in Man: Its Role in Altitude Acclimatization
Authors: Milledge J. S. , Catley D. M. 
Published: August 2015

1. The response of serum angiotensin converting enzyme (ACE) activity to three grades of hypoxia was studied in two groups of human subjects. Hypoxic gas mixtures having oxygen concentrations of 14, 12.6 and 10.4% were breathed successively for a period of 10 min at each concentration. Venous blood was sampled at the end of each of the three periods and arterial oxygen saturation was recorded throughout the experiment.
2. The subjects were selected as being ‘good’ or ‘poor’ acclimatizers according to their history of acute mountain sickness. There were five subjects in each group.
3. Hypoxia resulted in a reduction in ACE activity in both groups, the reduction being linear with respect to arterial oxygen saturation.
4. The reduction in ACE activity was greater in the good acclimatizer group as shown by a significantly greater slope of the response line of ACE activity to arterial oxygen saturation.
5. The significance of this finding in relation to the mechanism underlying acute mountain sickness is discussed.
Distribution of Dead Space Volume in the Human Lung
Authors: Tatsis George , Horsfield Keith , Cumming Gordon 
Published: August 2015

1. The first four breaths from a multi-breath nitrogen wash-out have been analysed in 20 normal subjects by differentiation and data smoothing of phase II of the expired concentrations of nitrogen and carbon dioxide.
2. This procedure yields a distribution curve which is skewed to the right, the mode of which represents the usual value of dead space. The minimum and maximum values were found by excluding 2.5% of data points at each end of the distribution.
3. The values of minimum, mode and maximum in men were 67.6, 147 and 300 ml. For women the values were 55.4, 109 and 235 ml.
4. It is suggested that this distribution reflects the asymmetrical nature of the bronchial tree and comparison with anatomical data suggests that anatomy is the principal determinant of the distribution of dead space.
5. The contribution made by the spread of the stationary interface within individual bronchioles is evident but small.
Progression to Renal Failure after Nephrotoxic Nephritis in Rats Studied by Renal Transplantation
Authors: El Nahas A. M. , Lechler R. , Zoob S. N. , Rees A. J. 
Published: August 2015

1. We studied the relation between immunopathology and progressive renal failure after nephrotoxic nephritis (NTN) in rats.
2. Thirty days after induction of nephritis by injection of rabbit anti-rat nephrotoxic serum, pairs of kidneys from 13 nephritic rats were transplanted into separate syngeneic recipients, one of whom had been pre-immunized with rabbit immunoglobulin G (IgG) whilst the other was naive.
3. Progression to renal failure of the transplanted nephritic kidney was studied after removal of the recipient's own kidneys; results from right and left kidney from a single donor in pre-immunized and naive recipients were compared.
4. There were substantial differences in autologous anti-rabbit IgG titres in naive and pre-immunized recipients; despite this pairs of kidneys from the same donor had almost identical courses as assessed by proteinuria, serum creatinine and graft survival.
5. There was substantial variation in survival of kidneys from different donors. But there were very strong correlations of graft survival with proteinuria (r = 0.97, t = 4.443, P&lt;0.001) and reciprocal serum creatinine (r = 0.95, t = 4.32, P&lt;0.001) in donors shortly before transplantation.
6. We conclude that autologous antibody titres did not influence the progression to renal failure after nephrotoxic nephritis. The rate of progression was already determined at the time of transplantation.
Evidence of Parasympathetic Activity of the Angiotensin Converting Enzyme Inhibitor, Captopril, in Normotensive Man
Authors: Campbell B. C. , Sturani Alessandra , Reid J. L. 
Published: August 2015

1. Captopril (50 mg orally) produced a significant fall in systolic and diastolic blood pressure in six normotensive sodium replete subjects, without a rise in heart rate.
2. On captopril, there was no change in the expected normal increase in heart rate on standing. Supine plasma noradrenaline was not reduced by captopril and normal postural increases were maintained.
3. Atropine (0.04 mg/kg i.v.) reduced the difference in blood pressure change between captopril and placebo.
4. Facial immersion in water produced a bradycardia. This change was abolished by atropine and attenuated both by captopril and edrophonium (10 mg i.V.), a cholinesterase inhibitor.
5. Lying down after 6 min standing produced an immediate transient tachycardia, which was abolished by atropine and attenuated by captopril.
6. Blood pressure and heart rate rose after a cold pressor test on both captopril and placebo.
7. The tachycardia during the Valsalva manoeuvre was inhibited by edrophonium and to a lesser extent by captopril. The effects of captopril and edrophonium were additive.
8. Parasympathetic activity of captopril may contribute to its haemodynamic profile.
Optimal Conditions for Measurement of Na+, K+-ATPase Activity of Human Leucocytes
Authors: Baron D. N. , Khan F. A. 
Published: August 2015

1. The Na+, K+-ATPase activity of human leucocytes was assayed by measuring the release of inorganic phosphate (Pi) from ATP.
2. The maximum enzyme activity was achieved under the following conditions: concentration (mmol/l), Tris/HCl 50, Na 100, K 15, ATP 5, Mg 7, EDTA 1; pH 7.2 and temperature 37°C, were optimal. Ouabain showed maximal inhibition at a concentration of 10-100 μmol/l. Ethanol, the solvent for ouabain, had a dose-related inhibitory effect.
3. Heparin or citrate used as an anticoagulant gave similar results. Leucocyte samples could be stored at −20°C for up to 6 days without loss of activity. Hypotonic lysis had advantages over sonication as the technique for cell disruption.
4. The leucocyte Na+, K+-ATPase enzyme activity in healthy subjects was 186 μmol of Pi h−1 g−1 of protein (median) with a range 136-243 μmol of Pi h−1 g−1 of protein. The within-batch coefficient of variation was 6.4% and the between-batch precision was 9.6%.
Haemodynamic and Endocrine Responses of the Kidney to Frusemide in Mild Essential Hypertension
Authors: Mackay I. G. , Nath K. , Cumming A. D. , Muir A. L. , Watson M. L. 
Published: August 2015

1. Prostaglandin-dependent, frusemide-induced changes in renal plasma flow, glomerular filtration rate and plasma renin activity were measured in 14 patients with mild essential hypertension.
2. The renal haemodynamic responses to frusemide were the same as in 10 normal subjects.
3. Frusemide-induced changes in urinary PGE and kallikrein excretion were also the same as in normal subjects.
4. Impaired renal release of vasodilator prostaglandins in essential hypertension is likely to be secondary to the hypertension rather than an underlying factor in its development.
Lack of effect of Naloxone in a Moderate dosage on the Exercise-Induced Increase in Blood Pressure, Heart Rate, Plasma Catecholamines, Plasma Renin Activity and Plasma Aldosterone in Healthy Males
Authors: Bramnert Margareta , Bernt Hökfelt 
Published: August 2015

1. There is evidence that opioid peptides influence blood pressure and heart rate in animals and man. In the present investigation the effect of naloxone on the exercise-induced increase in blood pressure, heart rate, plasma catecholamines, plasma renin activity (PRA) and plasma aldosterone was investigated in nine healthy men. A submaximal work test was performed on two occasions. The test consisted of ergometer bicycling for 10 min on 50% of maximal working capacity immediately followed by 10 min on 80% of maximal working capacity. Ten minutes before exercise the subjects received in a randomized manner a bolus dose of naloxone (10 μg/kg) or a corresponding volume of saline followed by a slow infusion (15 ml/h) of naloxone (5 μ h−1 kg−1) or saline, respectively.
2. After exercise systolic blood pressure, heart rate, plasma catecholamines, PRA and plasma aldosterone increased during both saline and naloxone infusion. The changes were similar in both studies.
3. Accordingly, opiate receptors sensitive to naloxone in a moderate dosage seem not to be involved in the cardiovascular response and the increase in plasma catecholamines, PRA and plasma aldosterone induced by exercise.
The effect of Intravenous Sodium Cromoglycate on the Bronchoconstriction Induced by Sulphur Dioxide Inhalation in Man
Authors: Allistone Anne , Collier J. G. , Davidson R. N. , Fuller R. W. , Richardson P. S. 
Published: August 2015

1. Ten healthy subjects received, on separate occasions, intravenous infusions of 0.9% NaCl solution (saline) and of sodium cromoglycate given in a double-blind cross-over fashion.
2. After 20 min of infusion the specific airway conductance (sGaw) of each subject was measured in a body plethysmograph. The subject then breathed first a low (1-20 p.p.m.) and then a higher (4-40 p.p.m.) concentration of sulphur dioxide (SO2) for 2 min while the infusion continued. Measurements of sGaw were repeated after each inhalation of SO2.
3. Sodium cromoglycate infusion did not affect the sGaw measured before challenge with SO2.
4. During the infusion of sodium cromoglycate, the falls in sGaw in response to both concentrations of SO2 were significantly less than those which occurred during saline infusion.
5. Plasma concentrations of sodium cromoglycate were found to be 209 ± 22 nmol/l at the end of the drug infusion. This is about one-hundredth of lowest dose required to stabilize mast cells in vitro.
6. We conclude that sodium cromoglycate acted by a mechanism which did not involve mast cells. Other possible modes of action are discussed.
Effect of the Calcium Antagonist Verapamil on Human Leucocyte Sodium Transport in vitro
Authors: Gray H. H. , Poston L. , Johnson V. E. , Hilton P. J. 
Published: August 2015

1. Sodium efflux rate constants and intracellular sodium were measured in leucocytes from healthy volunteers in the presence and absence of the calcium antagonist verapamil hydrochloride.
2. Verapamil stimulated sodium pump activity and this effect was dependent on the presence of external calcium.
3. Verapamil has been reported to reverse the abnormality of sodium transport seen in leucocytes from patients with essential hypertension and the present study demonstrates that sodium pump activity in leucocytes from control subjects is also stimulated by exposure to verapamil in vitro. This direct cellular effect appears to be due to the calcium antagonist properties of the drug.
The Causative Agent in Atrial Receptor Diuresis in the dog is a Low Molecular Weight, Lipophilic and Weakly Acidic Substance
Authors: Pither J. M. , Knapp M. F. , Gregory H. , Linden R. J. 
Published: August 2015

1. Stimulation of atrial receptors by distension of a balloon in the left atrium of anaesthetized dogs results in a reflex diuresis mediated by a humoral agent of unknown identity.
2. In previous investigations, a substance was recovered in a low molecular weight fraction from Bio-Gel P-2 (100-1800 daltons) and shown to be related to the reflex diuresis.
3. In this investigation, the active Bio-Gel P-2 fraction was partitioned with ethyl acetate at pH 11.0, with subsequent partition of the aqueous phase with ethyl acetate at pH 7.4; the activity of the humoral agent was soluble in ethyl acetate at pH 7.4.
4. These investigations suggest that the humoral agent is a low molecular weight, lipophilic and weakly acidic substance.
5. The substance is not antidiuretic hormone (ADH) as vasopressin is insoluble in ethyl acetate at pH 7.4.
Splenic pooling of granulocytes
Authors: Peters A. M. , Saverymuttu S. H. , Keshavarzian A. , Bell R. N. , Lavender J. P. 
Published: August 2015

1. The intrasplenic kinetics of granulocytes, isolated in plasma and labelled in plasma with 111In-tropolonate, have been studied in normal subjects, patients with negative studies for inflammatory disease and patients with positive studies, with the aim of identifying the nature of splenic activity seen after 111In-labelled granulocyte administration.
2. Up to 40 min after injection, 111In activity was visible only in major blood vessels, liver and spleen, with slight, abnormal activity visible in most of those with positive scans. The time courses of uptake of hepatic and splenic activity were different, with liver activity rapidly reaching a plateau and splenic activity increasing mono-exponentially to a plateau achieved between 20 and 40 min.
3. The clear difference between the shapes of the hepatic and splenic uptake curves and the magnitude of the splenic uptake rate constant indicated that splenic activity represented reversible uptake.
4. The application of deconvolution analysis to the blood and splenic time-activity curves generated a splenic retention (or washout) curve consistent with dynamic exchange of granulocytes between blood and spleen. The slope of this curve indicated an intrasplenic granulocyte transit time of 9.3 (±se 0.6) min.
5. Taking splenic activity to be reversible, comparison of the 111In signal from the spleen 40 min after injection of 111In-labelled granulocytes with that given from the spleen after the injection of 111In-labelled erythrocytes (relative to their respective blood levels) indicated that intrasplenic granulocyte transit time was 14.4 (±se 1.1) times that of erythrocytes. Based on actual erythrocyte time, this corresponds to a granulocyte transit time of 8.6-11.5 min, in close agreement with the estimate based on deconvolution analysis.
6. The reversibility of splenic 111In activity after labelled granulocyte injection was confirmed by observing falls in splenic activity between 40 min and 24 h and between 3 and 24 h, which were greater in patients with inflammatory disease than those without. Furthermore, a significant correlation was recorded between this fall and the fraction of the dose of 111In excreted in the faeces in patients with inflammatory bowel disease (IBD).
7. We conclude that the normal spleen contains a reservoir of granulocytes which is in dynamic equilibrium with circulating granulocytes (CGP). This pool therefore is a major component of the body's marginating granulocyte pool (MGP). The mean transit time of granulocytes through the spleen, about 10 min, is remarkably similar to that of platelets.