bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extrarenal synthesis of 1,25-dihydroxyvitamin D: Sensitivity to glucocorticoid treatment
Authors: Adami Silvano , Graziani G. , Tartarotti D. , Cappelli R. , Casati S. , Cantaluppi A. , Braga V. , Cascio V. Lo 
Published: August 2015

1. The response of circulating 1,25-dihydroxyvitamin D [l,25-(OH)2D] to challenge with vitamin D treatment both before and after 7–10 days of prednisone therapy (25 mg/day) was investigated in five anephric subjects, six patients with chronic renal failure (CRF), two patients with vitamin D intoxication and four patients with hypoparathyroidism.
2. In anephric subjects serum 25-hydroxyvitamin D [25-(OH)D] rose from 58 ± 48 (sd) to 377±221 (sd) nmol/l after administration of 150 μg of 25-(OH)D3 for 1 month. Serum l,25-(OH)2D, which was barely detectable in only two out of five patients under basal conditions, rose to 30 ± 21 pmol/l after 2 weeks of therapy with 25-(OH)D3, but fell to 10 ± 5 pmol/l during prednisone treatment.
3. In CRF patients circulating l,25-(OH)2D rose from 37 ± 24 to 58 ± 24 pmol/l during 25-(OH)D3 therapy, but fell to 41 ± 31 pmol/l during prednisone treatment. In two patients with rheumatoid arthritis, hypercalcaemia due to vitamin D intoxication was associated with raised levels of 1,25-(OH)2D (288 and 317 pmol/l). Administration of prednisore resulted in suppression of l,25-(OH)2D levels (132 and 96 pmol/l respectively) and reduction of serum calcium to within the normal range.
4. In the hypoparathyroid patients prednisone therapy did not affect circulating 25-(OH)D levels but serum l,25-(OH)2D fell from 192 ± 42 to 117 ± 23 pmol/l and serum calcium from 2.41 ± 0.21 to 2.20 ± 0.05 mmol/l.
5. These findings indicate that a steroid sensitive extrarenal production of l,25-(OH)2D may occur in all subjects with a threshold serum concentration of the precursor 25-(OH)D.
A randomized controlled trial of the effect of dietary fibre on blood pressure
Authors: Margetts Barrie M. , Beilin Lawrence J. , Vandongen Robert , Armstrong Bruce K. 
Published: August 2015

1. Eighty-eight healthy omnivores with normal blood pressure participated in a randomized, controlled, cross-over trial of the effect on blood pressure of increasing dietary fibre intake. Subjects were randomly allocated to a control group eating a low fibre diet throughout, or to one of two experimental groups eating a high fibre diet for one of two 6-week experimental periods. Changes in body weight, other dietary constituents and lifestyle factors were avoided as far as possible.
2. Twenty-four hour diet records showed a substantial increase in dietary fibre when subjects were on the high fibre diet.
3. There was no consistent effect of change in dietary fibre intake on group mean systoloic or diastolic blood pressures. Adjusting blood pressures for changes in other dietary components, plasma lipids, electrolytes, body weight and other lifestyle variables did not alter this result.
4. These findings do not support the hypothesis that the blood pressure lowering effect of a vegetarian diet is solely due to an increase in fibre intake.
The effect of prostaglandin E1 upon the pressor and hormonal response to exogenous angiotensin II in human pregnancy
Authors: Pipkin F. Broughton , Morrison R. , O'Brien P. M. S. 
Published: August 2015

1. The effect of prostaglandin E1 (PGE1) on the pressor and hormonal response to angiotensin (ANG) II has been studied in 22 women in second trimester pregnancy. Three-point dose–response curves were initially determined for all women. Eleven then received an infusion of PGE1 while the remainder received an infusion of normal saline as controls. The dose–response curves to ANG II were re-studied after a period of stabilization.
2. Although assignation to treatment group was random, differences were found in age and basal blood pressure between the control group and those given PGE1. The pressor data from the PGE1 group were thus split by age for analysis.
3. The administration of ANG II alone was associated with significant (P&lt;0.001 at all doses) pressor effects without accompanying bradycardia. Plasma renin concentration (PRC) was suppressed (P&lt;0.001). Plasma aldosterone concentration rose (P&lt;0.001), the magnitude of the rise being directly associated with the plasma ANG II concentrations achieved (P&lt;0.05).
4. The infusion of PGE, had no significant effect on basal blood pressure, but evoked a sustained tachycardia in both age groups (P&lt;0.001). Basal hormone concentrations were unchanged.
5. The pressor response to ANG II was blunted in the presence of PGE1, in both age groups, the overall effect being greatest when the initial response had been large (P&lt;0.05). Measured plasma concentrations of ANG II were lower under these circumstances (P&lt;0.02). PRC fell (P&lt;0.05 for both groups) and plasma aldosterone concentrations rose (P&lt;0.005 for the treated and P&lt;0.001 for the control groups), but the magnitude of these changes did not differ significantly in the two groups.
6. These data support the hypothesis of a for the vasodilator prostaglandins in minimizing the potential pressor effects of the raised ANG II concentrations seen in pregnancy.
Amiloride inhibits the rise of urinary kallikrein excretion induced by frusemide administration in the rat
Authors: Obika L. F. O. , MARIN-GREZ M. 
Published: August 2015

1. The effect of amiloride administration on the urinary kallikrein response to the injection or continuous infusion of frusemide in normal Sprague–Dawley rats was investigated.
2. Injections of frusemide induced repeatedly an increase in urinary kallikrein excretion. This effect was suppressed by amiloride. Amiloride also blocked the response to mannitol injection. A continuous infusion of frusemide lasting 100 min also induced an increase in urinary kallikrein excretion which persisted throughout the experiment. This response was completely blocked by the injection of amiloride.
3. Urinary kallikrein excretion was directly and positively related to urine volume and urinary sodium excretion before and after amiloride injection. The regression lines had markedly decreased slopes after amiloride administration. The urinary kallikrein excretion was also positively related to the urine volume and urinary sodium excretion when frusemide was continuously infused. However, these relationships were abolished after amiloride injection.
4. In both the injection and the infusion experiments, there was a direct relationship of urinary kallikrein excretion to urinary potassium excretion. Although this relationship persisted after amiloride injection, the regression line was shifted to the left.
5. The suppression of the kallikrein stimulating effect of frusemide by the sodium channel blocker amiloride indicates that distal tubule sodium re-absorption is the triggering factor in urinary kallikrein excretion. The study suggests that the mechanism involved in the release of kallikrein by the distal tubular cells is linked to the renal mechanism affected by amiloride.
The effects of four β-adrenoceptor antagonists during modest exercise on plasma ammonia and heart rate
Authors: Hall P. E. , Smith S. R. , Kendall M. J. 
Published: August 2015

1. Plasma ammonia and heart rate were measured in normal volunteers before, during and after an exercise test following administration of placebo, propranolol, pindolol, metoprolol and nadolol.
2. Small changes in plasma ammonia occurred during exercise after placebo. However, all four β-adrenoceptor antagonists produced considerably greater rises. This effect was most marked after propranolol with the response to pindolol, metoprolol and nadolol being similar and intermediate between placebo and propranolol.
3. Resting heart rate was reduced by all the β-adrenoceptor antagonists except pindolol. Exercise induced changes in heart rate were significantly reduced to a similar degree by all the β-adrenoceptor antagonists.
Multiple forms of immunoreactive renin in human adrenocortical tumour tissue from patients with primary aldosteronism
Authors: Mizuno Kenji , Ojima Motoko , Hashimoto Shigeatsu , Tani Makio , Niimura Susumu , Kunii Nobuyasu , Yabe Ryuji , Watari Hiroaki , Inagami Tadashi , Fukuchi Soitsu 
Published: August 2015

1. There is increasing evidence which suggests that the adrenal gland contains the renin–angiotensin cycle. The localization of renin has been reported to be mainly in the zona glomerulosa rather than the fasciculata medullary portion. In the present study we have investigated extracts from aldosteronomas (n = 3), which are believed to derive from the zona glomerulosa cells. In addition, we have attempted to characterize the biochemical properties of the adrenal renin.
2. Sizable quantities of renin-like activity (32.0 ± 7.7 ng of angiotensin I generated h−1 mg−1 of protein, mean ± SEM) were detected in the extracts. This renin-like activity was inhibited by anti-renin antibody raised against pure renin (mean, 95% of the total renin-like activity), indicating that it was not due to the non-specific action of proteases such as cathepsin D.
3. The optimum pH of the tissue renin-like enzyme was 6.0 for rat plasma substrate. Differences were found, however, in the molecular mass (36000, 37000, 44000 and 48000), binding to concanavalin A and isoelectric points (4.40, 4.68 and 5.00).
4. These results confirm the existence of specific renin in aldosteronoma. Renin microheterogeneity could be evidence for local production of the enzyme.
The effect of insulin-induced hypoglycaemia on gastrointestinal motility in man
Authors: Fellows I. W. , Evans D. F. , Bennett T. , Macdonald I. A. , Clark A. G. , Bloom S. R. 
Published: August 2015

1. The effect of insulin-induced hypoglycaemia on gastro-jejunal motility was studied in five, healthy, male subjects using tethered, pressure sensitive, radiotelemetry capsules.
2. Thirty minutes after the intravenous injection of soluble insulin (0.15 unit/kg body weight), a significant reduction in blood glucose concentration (control: 5.26 ± 0.19 sem mmol/l; insulin: 1.48 ± 0.44 mmol/l; P &lt; 0.001) was associated with a rise in heart rate (mean peak rise 29 ± 8 beats/min, P &lt; 0.05), systolic arterial blood pressure (mean peak rise 28 ± 4 mmHg, P &lt; 0.01) and plasma pancreatic polypeptide concentration (control: 20 ± 7 pmol/l; insulin: 287 ± 66 pmol/l; P &lt; 0.01). These events coincided with a short period of jejunal motor activity, which was not associated with gastric motor activity nor with raised plasma motilin concentrations.
3. During the control study, there were no changes in blood glucose concentration, heart rate, arterial blood pressure or plasma pancreatic polypeptide concentrations, and there was no jejunal motor activity.
4. The interval between successive gastric migrating motor complexes (MMC) was not significantly different in the insulin and control studies (control: median interval 110 min, range 108–148 min; insulin: median interval 124 min, range 115–125 min), suggesting that the fasting gastro-jejunal MMC and jejunal motor activity arose independently.
5. Insulin-induced hypoglycaemia is accompanied by jejunal motor activity, which may underlie the abdominal symptoms associated with hypoglycaemia.
The influence of oral alkali citrate on intestinal calcium absorption in healthy man
Authors: Rüumenapf G. , Schwille P. O. 
Published: August 2015

1. The influence of citrate on intestinal calcium absorption (CaA) was studied in eight healthy males.
2. On separate occasions, either a load containing 5 mmol of calcium chloride and 21 mmol of citrate in the form of sodium potassium citrate or a citrate-free vehicle load corrected for pH and cations was ingested. CaA was measured over 3 h with a 47Ca–85Sr double tracer method.
3. After citrate administration, 10 min fractional CaA decreased significantly from 30 to 110 min post-load, and 3 h cumulative CaA dropped to 54.6 ± (sem)6.1% of the total dose as opposed to 76.3 ± 4.5% after vehicle administration (P &lt; 0.002). Citrate administration raised serum and urinary citrate, but had little effect on blood acid–base status. After both loads, urinary specific activity of 47Ca significantly correlated with 3 h cumulative CaA, while citrate administration decreased urinary calcium excretion only slightly as compared with vehicle.
4. The results suggest that, in man, higher doses of oral citrate inhibit CaA, probably by way of intraluminal complexation of calcium by citrate.
5. The finding might help explain the fall in urinary calcium excretion observed in patients treated with alkali citrate for recurrent calcium urolithiasis.
Permeability of the rat small intestine to carbohydrate probe molecules
Authors: Hamilton I. , Rothwell J. , Archer D. , Axon A. T. R. 
Published: August 2015

1. Absorption of carbohydrate probe molecules from ligated loops of rat small intestine was studied. Absorption was determined by measuring recovery of molecules in the urine, corrected for incomplete recovery after intravenous injection, and was examined for correlation with several parameters of molecular dimension.
2. Absorption depended on molecular volume rather than relative molecular mass, molecular radius or molecular area.
3. Molecules with a molecular volume below 225 × 10−3 nm3 were absorbed to a greater extent than larger molecules, and absorption was affected critically by molecular volume, small changes in volume producing considerable variation in absorption.
4. Absorption of larger molecules was not affected by changes in volume within the range 362 × 10−3–1128 × 10−3 nm3.
5. These findings support the concept that there are at least two aqueous diffusion pathways across the intestinal mucosa, small molecules diffusing through a small channel of finite dimension, compatible with a transcellular aqueous pore, whilst large molecules diffuse through a less frequent pathway of considerably larger dimensions.
Measurement of secretion in nasal lavage
Authors: Bisgaard Hans , Krogsgaard Ole W. , Mygind Niels 
Published: August 2015

1. The amount of admixture in nasal lavage fluids was determined by addition of 99mTc labelled albumin, providing a correction factor for measurements of cellular material and humoral substances in nasal lavage return as well as a quantitative measure of nasal secretions.
2. Albumin was chosen as marker molecule, since only negligible amounts were absorbed or adsorbed to the mucosa during the nasal lavage.
3. Labelling of the albumin with 99mTc ensured an accuracy of measurements only limited by the precision of the weighing. The isotope allowed for the determination of the amount of admixed secretion to be carried out on the whole sample of lavage fluid, thereby avoiding the necessity of complete admixture between marker and lavage fluid which would be pertinent to marker molecules measured chemically. The radiation from a nasal lavage is minimal and the procedure is fully acceptable for repeated use in humans.
4. The nasal lavage technique adopted allowed the return of 99.2% (median value) of the instilled volume. The area irrigated was visualized on a gamma-camera, and was demonstrated to cover an area larger than the area reached by challenge from a pumpspray, i.e. a large part of the nose, yet not the oropharynx.
5. A dose related increase in nasal secretion harvested by the nasal lavage in 10 persons challenged with histamine chloride could be demonstrated by this technique.
6. It is concluded that the use of 99mTc-albumin in a nasal washing provides a safe, simple and quick method for determination of the admixed nasal secretion with a remarkable degree of accuracy. The method is therefore suggested to improve determinations of admixture in nasal lavage fluid.
Erythrocyte cation fluxes during the menstrual cycle in normal female subjects
Authors: Monaghan J. C. , Willcocks D. A. , Sinosich M. J. , Stokes G. S. 
Published: August 2015

1. Studies of erythrocyte cation transport mechanisms in vitro were performed on eight normotensive, premenopausal female subjects at the mid-points of the follicular and luteal phases of their menstrual cycles. Concurrent plasma concentrations of 17β-oestradiol, progesterone, aldosterone and renin activity were measured.
2. Ouabain-resistant, frusemide-resistant rubidium influx (an index of passive potassium diffusion) was significantly lower in the luteal than the follicular phase.
3. In further studies in four of the eight subjects, the mean rate constant of the rubidium influx measurement was also lower in the luteal than in the follicular phase.
4. There were no changes in Na+-K+ co-transport, sodium pump activity or intracellular cation concentrations throughout the cycle.
5. There was a tenfold fall in the mean plasma 17β-oestradiol/progesterone ratio, as well as increases in plasma aldosterone concentration and renin activity between the mid-follicular and mid-luteal phases.
6. We conclude that changes in plasma oestrogen/progesterone ratio during the menstrual cycle may be associated with alterations in passive potassium diffusion.
Enhanced diurnal variation of blood pressure in the renal hypertensive rat: effect of angiotensin II suppression
Authors: Wallace E. C. H. , Balmforth A. J. , Morton J. J. 
Published: August 2015

1. Chronic two-kidney, one-clip hypertensive rats were infused with captopril for 5 days and the daily variability of blood pressure compared with that for both hypertensive rats infused with glucose and normotensive animals.
2. Blood pressure was measured continuously using a computer data collecting system.
3. Normotensive animals showed a stable level of arterial pressure throughout each 24 h period with troughs occurring when they slept during the daytime.
4. Hypertensive animals given glucose had an enhanced diurnal rhythm of blood pressure compared with normotensive rats, with peaks occurring during periods of activity at night as well as troughs when they slept during the day.
5. Hypertensive rats given captopril retained this enhanced pressure variability, in spite of the fact that blood pressure was significantly lower and angiotensin II was suppressed.
6. These results suggest that angiotensin II is not involved in the increased blood pressure variability of renal hypertension and that some other irreversible mechanism is responsible.
Loop-acting diuretics do not bind to Tamm–Horsfall urinary glycoprotein
Authors: Brunisholz M. C. , Lynn K. L. , Hunt J. S. 
Published: August 2015

1. Binding between the radiolabeled loop-acting diuretics ([14C]frusemide, [14C]ethacrynic acid and [3H]bumetanide) and human Tamm–Horsfall glycoprotein or human serum albumin in vitro was evaluated by equilibrium dialysis.
2. The diuretic action and binding to urinary Tamm–Horsfall glycoprotein of the radiolabeled diuretics in vivo, after intravenous administration, were examined in rabbits.
3. In vitro, all three radiolabeled diuretics bound strongly to human serum albumin, but not to Tamm–Horsfall glycoprotein.
4. Radiolabeled frusemide and bumetanide, but not ethacrynic acid, caused a diuresis in rabbits, but no binding between the drugs and Tamm–Horsfall glycoprotein was seen in vivo.
5. Binding to Tamm–Horsfall glycoprotein does not appear to be an important mechanism in the action of loop diuretics.
Detection of Hypercapnia by Normal Subjects
Authors: Schwartzstein R. M. , Hive K. La , Pope A. , Steinbrook R. A. , Leith D. E. , Weiss J. W. , Fencl V. , Weinberger S. E. 
Published: August 2015

1. To investigate whether changes in Paco2 can be detected independently of the CO2-induced changes in pulmonary ventilation, we tested five normal subjects for the ability to distinguish different levels of end-tidal Pco2 (PETco2) while holding minute ventilation constant.
2. Helped by a visual feedback system, the subjects maintained a constant ventilation targeted at a level that was higher than that dictated by the chemical drive at PETco2 = 50 mmHg (6.7 kPa). End-tidal Pco2 was held at 40 mmHg (5.3 kPa) during the first 2 min of each test trial ('control period'); then, for 4 min ('test period'), PETco2 was either elevated to 50 mmHg or kept at 40 mmHg. Twelve runs were performed by each subject.
3. In 24 out of the total 30 trials (80%) in which PETco2 was raised during the test period to 50 mmHg, the subjects detected the changes. There was one false positive result (3%), when PETco2 kept at 40 mmHg during the test period was reported as different from control. In four out of the five subjects the ability to detect the change in PETco2 from 40 to 50 mmHg was statistically significant.
4. We conclude that increases in PETco2 can be detected independently of changes in the absolute level of ventilation.
Changes in plasma renin, insulin, aldosterone and arginine vasopressin during plasmapheresis
Authors: Rainfray MUriel , Pruszczynski Wojciech , Bussel Annette , Ardaillou Raymond 
Published: August 2015

1. Nineteen patients with a spectrum of immunologically related disorders were studied before and immediately after plasmapheresis for changes in plasma aldosterone, insulin and arginine vasopressin (AVP). Renin was also measured in 11 of these patients by direct radioimmunoassay. 125% of the initial plasma volume was replaced, which corresponded to a predicted removal of 72% for any plasma constituent.
2. The intial, final (experimental) and final (predicted) concentrations (means ± sem) were 337 ± 50, 185 ± 23 and 100 ± 16 pg/ml respectively for renin, 465 ± 86, 146 ± 38 and 124 ± 22 pmol/l respectively for aldosterone, 218 ± 35, 69 ± 11 and 63 ± 11 pmol/l respectively for insulin, 7.2 ± 1.9, 6.1 ± 0.5 and 1.8 ± 0.2 pmol/l respectively for AVP. The predicted final concentration was calculated from the initial concentration and the fraction of plasma volume exchanged. The experimental final concentration was lower than the initial concentration for renin, aldosterone and insulin (P &lt; 0.001) but not for AVP. The predicted final concentration was lower than the experimental final concentration for AVP and renin (P &lt; 0.001) but not for aldosterone and insulin. Plasma volume, osmolality, glucose, sodium and potassium concentrations did not change significantly.
3. The concentrations of renin, aldosterone, insulin and AVP in the removed plasma were 84 ± 17 pg/ml, 179 ± 36, 98 ± 15 and 4.8 ± 0.7 pmol/l respectively. The amount subtracted expressed as percentage of the total amount present in plasma was markedly greater for AVP than for the three other plasma constituents.
4. These results demonstrate that the response of the releasing cells to the fall in the plasma concentration of their secretory product does not follow the same kinetics for all substances. There is probably for AVP a fast releasing pool stimulated by a negative feedback.
Substrate induction of bilirubin conjugation and biliary excretion in the rat
Authors: Muñoz Maria E. , Esteller Alejandro , González Javier 
Published: August 2015

1. The effect of high bilirubin loads (60 μmol/kg twice daily for 2 days) on glucuronosyltransferase activity and biliary excretion of bilirubin was studied in Wistar rats.
2. The concentration of bilirubin in serum increased from 1.1 μmol/l in controls to 5.5 μmol/l after bilirubin pretreatment.
3. Bilirubin pretreatment led to a 25% increase in hepatic UDP-glucuronosyltransferase activity. Bilirubin Tm, was increased by 22% and correlated positively with glucuronosyltransferase activity.
4. The output of conjugated bilirubin in bile was enhanced but no changes in the proportion of monoconjugates to diconjugates were observed.
5. Our data suggest that prolonged treatment with bilirubin can increase biliary bilirubin excretion by inducing glucuronosyltransferase activity.