bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the Renin-Angiotensin System in a Kininogen-Deficient Individual
Authors: Wong Patrick Y. , Williams Gordon H. , Colman Robert W. 
Published: August 2015

1. The physiological responses of the renin-angiotensin system were studied in an individual with kininogen deficiency (patient 1) with absent plasma bradykinin and markedly impaired prekallikrein conversion into kallikrein. After sodium depletion, patient 1 had a low plasma renin activity (1.4 pmol of ANG I h−1 ml−1) and a low angiotensin II concentration (36 pg/ml) compared with values in 11 normal individuals (4.0 ± 0.94 pmol of ANG I h−1 ml−1) and 63 ±6 pg/ml respectively).
2. Unlike normal individuals, in the kininogen-deficient subject there was no significant fall of renin activity or angiotensin II after dietary sodium repletion. Intravenous sodium repletion also failed to further decrease plasma renin activity or angiotensin II.
3. The usual two- to three-fold rise in plasma renin activity and angiotensin II observed in normal subjects on assumption of the upright posture after ingestion of 200 mg of sodium/day failed to occur in the kininogen-deficient individual.
4. These data in vivo are in agreement with observations in vitro that once plasma kallikrein forms it may be important in converting prorenin into renin. In the absence of kininogen, activation of prekallikrein to kallikrein is grossly defective, which may in part account for the diminished response of the renin-angiotensin system to changes in sodium balance and posture.
Adrenaline Secretion during Exercise
Authors: Warren J. B. , Dalton N. , Turner C. , Clark T. J. H. , Toseland P. A. 
Published: August 2015

1. By studying six normal subjects during graduated treadmill exercise, we have confirmed that there is very little rise in venous plasma adrenaline levels during mild or moderate exercise.
2. During a second study, adrenaline was infused intravenously in six resting subjects at a rate of 0.025 μg min−1 kg−1. This elevated the basal plasma adrenaline level from 0.28 ± 0.04 nmol/l to 0.92 ± 0.16, 1.16 ± 0.20 and 1.28 ± 0.19 nmol/l at 3, 5 and 7 min after the start of the infusion.
3. The same adrenaline infusion was repeated in the same subjects 7 min after they started moderate exercise at a constant rate on a static exercise bicycle. Just before the start of the infusion, 7 min after the onset of exercise, plasma adrenaline had risen to 0.36 ± 0.07 nmol/l. This rose to 1.86 ± 0.30, 1.98 ± 0.26 and 2.19 ± 0.29 nmol/l at 3, 5 and 7 min after the start of this second infusion. Five minutes after the end of the infusion, while the subjects were still exercising, the mean level was 0.56 ± 0.04 nmol/l.
4. The venous plasma level of adrenaline is the result of a balance between the secretion of adrenaline by the adrenal medulla and the clearance of adrenaline from plasma. Our results suggest that the lack of any significant rise in plasma adrenaline during moderate exercise does not result from an accelerated clearance of adrenaline by exercising tissue. The clearance rate of adrenaline from plasma is reduced during exercise.
5. There is no significant increase in secretion by the adrenal medulla in response to the stimulus of mild or moderate exercise.
The Effect of Water Abstention on Milk Synthesis in Lactating Women
Authors: Prentice A. M. , Lamb W. H. , Prentice Ann , Coward W. A. 
Published: August 2015

1. The effects of dehydration on mechanisms of water balance and milk synthesis were investigated in ten lactating Gambian women who were fasting during Ramadan. Ten non-pregnant, non-lactating women acted as controls. Fasting consisted of total water abstention from 05.00 hours to 19.30 hours and was accompanied by high insensible water losses.
2. Lactating women lost 7.6% of their total body water between 07.00 hours and 19.00 hours. Control subjects lost significantly less.
3. Plasma indices of dehydration (osmolality, sodium, uric acid) showed a greater rise in the lactating women than in the control subjects over the period of fasting. However, the 19.00 hours values remained in the normal range obtained on non-Ramadan days.
4. During Ramadan the lactating women restricted their urinary output to a lesser degree than the controls, and for much of the day their urine was also less concentrated. The lactating women appeared to have adapted by superhydrating themselves overnight. This resulted in very low urine concentrations (osmolality, sodium, urea, creatinine) in morning samples. Urine concentrations approached, but did not exceed, non-Ramadan levels by late afternoon.
5. The daily water turnover of 6.4 litres in the lactating women was 2 litres greater than in the controls. This difference was much greater than that required for milk synthesis (500 ml) and may represent a further protective mechanism.
6. Fasting caused changes in milk osmolality, lactose, sodium and potassium concentrations indicative of a marked disturbance of milk synthesis. The results suggested that the normally tight junctions between the mammary secretory cells had become permeable to small ions and formed a paracellular pathway.
The Mechanism of Action of Guar Gum in Improving Glucose Tolerance in Man
Authors: Blackburn N. A. , Redfern J. S. , Jarjis H. , Holgate A. M. , Hanning I. , Scarpello J. H. B. , Johnson I. T. , Read N. W. 
Published: August 2015

1. Experiments were carried out in human volunteers to investigate the mechanism by which guar gum improves glucose tolerance.
2. Guar reduced both plasma glucose and insulin responses to an oral glucose load, and delayed gastric emptying. However, there was no correlation between changes in individual blood glucose responses and changes in gastric emptying rates induced by guar.
3. With a steady-state perfusion technique, glucose absorption was found to be significantly reduced during perfusion of the jejunum with solutions containing guar, but returned to control values during subsequent guar-free perfusions.
4. Preperfusing the intestine with guar did not affect electrical measurements of unstirred layer thickness in the human jejunum in vivo..
5. Experiments in vitro established that glucose diffusion out of a guar/glucose mixture was delayed under conditions of constant stirring.
6. We conclude that guar improves glucose tolerance predominantly by reducing glucose absorption in the small intestine. It probably does this by inhibiting the effects of intestinal motility on fluid convection.
Polymorphisms in the 5′-Flanking Region of the Insulin Gene and Non-Insulin-Dependent Diabetes
Authors: Hitman G. A. , Jowett N. I. , Williams L. G. , Humphries S. , Winter R. M. , Galton D. J. 
Published: August 2015

1. DNA insertions in the 5′-flanking region of the insulin gene have been studied by Southern-blot-hybridization techniques using a cloned gene probe in 159 unrelated Caucasians.
2. Subjects homozygous for a large DNA insertion at this locus were found to have a higher risk of concurrence of non-insulin-dependent diabetes (NIDD) than controls (P &lt; 0.01).
3. Analysis of a single large NIDD pedigree (n = 67 in four generations; 11 diabetic subjects) showed no linkage between the size of DNA inserts and diabetes (Lod score = −5.7), suggesting a separate diabetogenic locus (or loci) in this family.
A non-Invasive Technique for Continuous Monitoring of Left Ventricular Function Using a New Solid State Mercuric Iodide Radiation Detector
Authors: Lahiri A. , Crawley J. C. W. , Jones R. I. , Bowles M. J. , Raftery E. B. 
Published: August 2015

1. A miniature solid-state mercuric iodide (HgI2) nuclear probe detector has been developed in conjunction with a computerized nuclear probe (Nuclear Stethoscope) to enable continuous noninvasive monitoring of left ventricular function using 99Tc-labelled equilibrium blood pool techniques.
2. Left ventricular ejection fraction was measured in 54 patients undergoing radionuclide angiography with a gamma-camera and with the Nuclear Stethoscope and a good correlation was obtained between both techniques (r = 0.94, n = 54, P &lt; 0.001).
3. The prototype mercuric iodide detector was compared with the sodium iodide detector of the Nuclear Stethoscope and a study in 41 consecutive patients demonstrated a good correlation for the measurement of ejection fraction, ejection rate, peak filling rate and time to peak filling rate (r = 0.94, 0.89, 0.90 and 0.78 respectively).
4. It may be possible to adapt the mercuric iodide detector for continuous non-invasive monitoring of left ventricular performance in critically ill patients and during physiological or pharmacological interventions.
Urinary pH as a determinant of prostaglandin E2 excretion by the conscious rat
Authors: Haylor J. , Lote C. J. , Thewles A. 
Published: August 2015

1. The urinary excretion of prostaglandin E2 (PGE2) was measured in conscious rats under conditions which produced either acid or alkaline urine, but similar change in fluid and solute excretion.
2. Oral isotonic saline increased both urine flow and sodium excretion but did not alter urinary PGE2 output (which remained constant at 80 pmol/3 h per rat) or urine pH (6.2).
3. When the urine was made alkaline (pH 7.8) by oral sodium bicarbonate or carbonate, urinary PGE2 was approximately 3-fold greater (P&lt;0.00l) than the control (pH6.2). The urine flow and sodium output were also increased.
4. When the urine was made acidic (pH 5.7) by oral ammonium chloride, urinary PGE, excretion was reduced (P&lt;0.01) to approximately half the control output. The urine flow and sodium output increased.
5. Within a group of 12 rats receiving oral isotonic saline a positive linear correlation coefficient (P&lt;0.002) was established between urine pH and PGE2 excretion.
6. The results indicate that urine pH may be a determinant of PGE2 excretion in unrestrained, conscious rats. It seems likely that this effect of pH is mediated by a change in the passive reabsorption of PGE, in the distal nephron, although alternative explanations such as altered tubular secretion or synthesis cannot be categorically excluded.
Response to indomethacin and hydrochlorothiazide in nephrogenic diabetes insipidus
Authors: Monnens L. , Jonkman A. , Thomas C. 
Published: August 2015

1. Four boys with classical nephrogenic diabetes insipidus have been treated by indomethacin, by hydrochlorothiazide, and by the combination of indomethacin and hydrochlorothiazide.
2. Hydrochlorothiazide treatment was slightly more effective than indomethacin treatment in reducing the urine volume and increasing the urine osrnolality.
3. The combination of indomethacin and hydrochlorothiazide appeared to be additive and especially helpful in infants and young children before the autonomy of drinking.
Association of Secondary Hyperparathyroidism with Red Cell Survival in Chronic Haemodialysis Patients
Authors: Saltissi D. , Carter G. D. 
Published: August 2015

1. 51Cr red cell mass (RCM), 51Cr red cell survival (RCS) and plasma parathyroid hormone (PTH) levels were measured in 27 stable chronic haemodialysis patients with a variable degree of clinical secondary hyperparathyroidism. Included were five patients who had had total parathyroidectomy.
2. The results showed a strong negative correlation between PTH and RCS (r = −0.67, P&lt;0.001) and a positive correlation between RCS and RCM (r = + 0.53, P&lt;0.005). However, the negative correlation between PTH and RCM was weak (r = −0.45, P&lt;0.02). When the 13 patients with normal PTH levels (mean 0.18 ± 0.12 μg/l) were compared with the 14 patients with raised levels (mean 1.35 ± 0.71 μg/l), there was a marked difference in RCS (P&lt;0.005) but no difference in RCM.
Altered Neuropeptide Concentrations in Spontaneously Hypertensive Rats: Cause or Consequence?
Authors: Gaida W. , Lang R. E. , Kraft K. , Unger Th. , Ganten D. 
Published: August 2015

1. Changes in brain neuropeptide content in spontaneously hypertensive rats may be primarily related to the development of hypertension or may be secondary consequences of it.
2. We have measured brain concentrations of β-endorphin, Leu-enkephalin, arginine vasopressin (AVP) and oxytocin (OXT) in stroke-prone spontaneously hypertensive rats (SHRSP) and in age-matched normotensive Wistar Kyoto (WKY) controls, as well as in SHRSP with normalized blood pressure by chronic treatment with clonidine. Opioid peptide contents were measured in 12-, 18- and 24-week-old rats. β-Endorphin was measured in the neuro-intermediate and anterior lobes of the pituitary, the hypothalamus, midbrain and brain stem; Leu-enkephalin in the neuro-intermediate lobe of the pituitary, hypothalamus, mid-brain, brain stem, as well as in the spinal cord and adrenal glands. AVP and OXT were measured in the neuro-intermediate lobe of the pituitary, hypothalamus, brain stem and spinal cord.
3. β-Endorphin in the neuro-intermediate lobe of the pituitary was significantly higher in 12- and 18-week-old SHRSP. Adrenal gland Leu-enkephalin was lower in SHRSP as compared with the WKY.
4. OXT and AVP contents were markedly reduced in all brain regions of SHRSP except the neuro-intermediate lobe of the pituitary, where no significant changes were found.
5. In no case did long-term antihypertensive treatment with clonidine reverse the altered peptide content in the SHRSP.
6. We conclude that alterations in brain neuropeptide content in SHRSP are not secondary to hypertension. The blood pressure lowering activity of clonidine appears not to depend on major alterations of peptide concentrations. A genetic defect in the synthesis of adrenal enkephalins and hypothalamic OXT and AVP seems likely from these studies.
The contribution of the renin-angiotensin system to limb vasoregulation in patients with heart failure: observations during orthostasis and α-adrenergic blockade
Authors: Creager Mark A. , Faxon David P. , Rockwell Susan M. , Gavras Haralambos , Coffman Jay D. 
Published: August 2015

1. In patients with congestive heart failure, both the sympathetic nervous system and renin-angiotensin system are often stimulated. In order to assess the contribution of the renin-angiotensin system to limb vascular resistance, the forearm haemodynamic response to captopril was studied in 13 patients with heart failure.
2. Seven subjects were studied while supine and during 60° head-up tilt. To eliminate α-adrenergic effects, six additional patients with heart failure were pretreated with intra-arterial phentolamine and then given captopril. Venous occlusion plethysmography was used to determine forearm blood flew and forearm vascular resistance.
3. Tilt did not significantly increase pretreatment plasma renin activity or plasma noradrenaline concentration, nor did it decrease forearm blood flow. Furthermore, captopril did not alter forearm vascular resistance during supine or upright posture. During the phentolamine infusion, however, captopril reduced forearm vascular resistance by 19% (P &lt; 0.05).
4. Despite increased plasma renin activity, captopril did not cause forearm vasodilatation during supine or upright posture in these patients with heart failure. When the contribution of the sympathetic nervous system was eliminated, captopril decreased forearm vascular resistance. Therefore, in patients with congestive heart failure, the sympathetic nervous system is important in limb vasoregulation, and the contribution of the renin-angiotensin system is apparent only after α-adrenergic blockade.
The mechanisms of action of noradrenaline on ouabain-sensitive rubidium uptake in guinea-pig myocardium
Authors: Wanless Richard B. , Noble Mark I. M. , Drake-Holland Angela J. D. 
Published: August 2015

1. The mechanism by which noradrenaline stimulates ouabain-sensitive rubidium uptake in guinea-pig myocardial tissue has been studied.
2. The stimulatory action of low concentrations of noradrenaline was reversed by high doses of propranolol (10−5 mol/l) in atrial tissue, but was not reversed by α- or β-, or combined α- and β-adrenoceptor antagonists in ventricular tissue.
3. Rubidium uptake was also found to increase with increasing extracellular potassium concentration ([K]o). The percentage values of stimulation by noradrenaline decreased with increasing [K]o.
4. Noradrenaline had no effect on the rate of ATP splitting by an isolated membrane preparation of Na,K-ATPase.
5. It is proposed that noradrenaline stimulates active cation transport by either (a) an effect secondary to increased passive efflux of K ions, or (b) an action at a novel adrenergic receptor, distinct from the ATPase enzyme itself.
Effects of erythrapheresis on pulmonary haemodynamics and oxygen transport in patients with secondary polycythaemia and cor pulmonale
Authors: Wallis P. J. W. , Skehan J. D. , Newland A. C. , Wedzicha J. A. , Mills P. G. , Empey D. W. 
Published: August 2015

1. Reducing packed cell volume has been advocated as a therapeutic procedure in patients with polycythaemia secondary to hypoxic cor pulmonale. The aim of this investigation was to evaluate the effects of this manoeuvre on resting pulmonary haemodynamics and tissue oxygenation in 12 such patients.
2. The subjects were studied whilst they were breathing air (n = 12), after breathing 35% oxygen for 30 min (n= 11) and breathing air 30 min after isovolaemic reduction in packed cell volume, from 0.61 ±0.02 to 0.50 ±0.02 (mean ± sem), by erythrapheresis (n = 12). Initial values for the group were: Pao2 6.5 ± 0.3 kPa; red cell mass 152 + 12% predicted; mean pulmonary artery pressure (PAP) 41 ± 3 mmHg; cardiac index 3.1 ± 0.3 1 min−1 m−2.
3. Breathing 35% oxygen reduced PAP by 3.1 ± 1.0 mmHg (P &lt; 0.02), cardiac index by 0.28 ± 0.121 min−1 m−2 (P &lt; 0.05) and right ventricular stroke work by 0.05 ± 0.01 J (P &lt; 0.01). Systemic vascular resistance was unchanged. Systemic oxygen transport increased and peripheral oxygen consumption was unaltered.
4. Erythrapheresis reduced blood viscosity at shear rates 23 s−1 and 230 s−1. PAP fell by 2.4 ± 1.1 mmHg (P &lt; 0.05) and cardiac index increased by 0.32 ± 0.09 1 mm−1 m−2 (P &lt; 0.01), but right ventricular stroke work was unchanged. Systemic vascular resistance was reduced by 25 ± 7 kPa s l−1 (P &lt; 0.01). Systemic oxygen transport decreased but peripheral oxygen consumption was unchanged.
5. These results confirm the effect of oxygen in reducing PAP in patients with hypoxic cor pulmonale. Reducing blood viscosity by reversing polycythaemia also improved pulmonary haemodynamics but unlike oxygen its effects were not confined to the pulmonary circulation.
6. Although erythrapheresis reduced the oxygen carrying capacity of the blood, tissue oxygenation was not impaired at rest. However, oxygen transport during exercise was not assessed in this study.
Chronic effects of oral sulindac on renal haemodynamics and hormones in subjects with chronic renal disease
Authors: Swainson Charles P. , Griffiths Peter , Watson Michael L. 
Published: August 2015

1. The effects of oral sulindac, 600 mg daily, on renal function and plasma hormones were studied in eight subjects with chronic renal failure.
2. Renal function and plasma hormones were measured before drug administration and then after taking sulindac for 28 days.
3. Effective renal plasma flow was reduced in all subjects after 28 days but the glomerular filtration rate did not change.
4. Plasma renin activity, potassium and aldosterone concentrations and urinary sodium excretion did not change but urinary prostaglandin E2 excretion fell significantly.
5. Sulindac may be a relatively renal-sparing drug in its effects on the hormonal control of glomerular function.
The contribution of the autonomic nervous system, the renin-angiotensin system and vasopressin to the maintenance of arterial blood pressure in adrenalectomized Wistar rats
Authors: Gardiner S. M. , Bennett T. 
Published: August 2015

1. Factors contributing to the maintenance of resting arterial blood pressure in sham-operated and adrenalectomized rats were assessed 14 weeks after operation; some animals were given 1% NaCl to drink throughout, and some animals were given sodium-free water instead of 1% NaCl for 2 days before the experiment.
2. Inhibition of the renin-angiotensin (ANG) system (with captopril) and of the cardiovascular actions of vasopressin [with 1-(β-mercapto-β,β-cyclopentamethylenepropionic acid), 8-d-arginine vasopressin (d(CH2)5DAVP)] had no hypotensive effects in sham-operated rats under any conditions, but antagonism of nicotinic ganglionic transmission (with pentolinium) caused a prompt fall in blood pressure. During combined administration of captopril, d(CH2)5DAVP and pentolinium to sham-operated rats, there was no significant recovery of blood pressure.
3. Adrenalectomized rats drinking 1% NaCl showed a marked hypotension and tachycardia in response to captopril, but d(CH2)5DAVP had little effect, whether administered before or after captopril. Addition of pentolinium rendered these animals more hypotensive man the sham-operated rats.
4. Adrenalectomized rats drinking sodium-free water for 2 days were hypotensive and blood pressures were lowered further by d(CH2)5DAVP or captopril under these conditions; there was no accompanying tachycardia.
5. The results indicate that, in chronically adrenalectomized rats drinking 1% NaCl, blood pressure is maintained by autonomic nervous and renin-ANG systems with no discernible contribution from the peripheral cardiovascular actions of vasopressin. However, the latter contribute importantly to the support of blood pressure when the adrenalectomized rats are rendered hypovolemic and hypotensive by substitution of sodium-free water to drink.
Inhaled smoke volume, puffing indices and carbon monoxide uptake in asymptomatic cigarette smokers
Authors: Woodman G. , Newman S. P. , Pavia D. , Clarke S. W. 
Published: August 2015

1. Nine asymptomatic smokers each smoked one cigarette of their usual brand on four separate occasions.
2. The inhaled smoke volume was measured by tracing the smoke with the inert gas 81Krm. Puffing indices were recorded by using an electronic smoking analyser and flowhead/cigarette holder. The expired air carbon monoxide concentration was measured immediately before and within 5 min of finishing smoking.
3. The inhaled smoke percentage (total inhaled smoke volume/total puff volume) averaged 46% to 85% in different subjects.
4. Neither the mean inhaled smoke volume per puff nor the total inhaled smoke volume per cigarette was significantly correlated with any of the puffing indices.
5. Smokers took significantly smaller and shorter puffs, left longer between puffs and inhaled less smoke as the cigarette was smoked (P &lt; 0.01), although the proportion of the puff which was subsequently inhaled did not change significantly.
6. There was no significant intra-subject difference in any index from one visit to another.
Rod mediated retinal dysfunction in cats with zinc depletion: Comparison with taurine depletion
Authors: Jacobson S. G. , Meadows N. J. , Keeling P. W. N. , Mitchell W. D. , Thompson R. P. H. 
Published: August 2015

1. Cats fed for 4 months with a diet with less than 7 p.p.m. zinc developed tissue zinc depletion, as judged by reduced muscle zinc content.
2. Dark adapted electroretinogram (ERG) thresholds became elevated in zinc depleted cats. Electroretinograms and muscle zinc levels were reversed by zinc supplementation.
3. Rod ERG to suprathreshold stimuli became reduced in b-wave amplitude in cats with zinc depletion, but suprathreshold cone ERG were unchanged.
4. The ERG changes in zinc depleted cats were unlike those in cats fed on a taurine depleted diet.