bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnesium Reduces Calcium Oxalate Crystal Formation in Human Whole Urine
Authors: Hallson P. C. , Rose G. A. , Sulaiman S. 
Published: August 2015

1. A low urinary magnesium was induced in normal volunteer subjects by giving cellulose phosphate; magnesium was added in vitro to yield urine samples of normal and high magnesium concentrations
2. After rapid evaporation of these urine samples at pH 5.3 to standard osmolality the calcium oxalate crystals were measured by microscopy and isotopic methods
3. There was a clear inverse correlation between magnesium concentration and calcium oxalate crystal formation
4. The case for treating calcium oxalate urolithiasis with magnesium is strengthened.
Factors affecting Excretion of Human Urinary Tamm—Horsfall Glycoprotein
Authors: Lynn K. L. , Shenkin A. , Marshall R. D. 
Published: August 2015

1. Tamm—Horsfall glycoprotein was determined, by radioimmunoassay, in samples of urine from normal individuals under a variety of physiological conditions
2. The amount of glycoprotein excreted in 24 h by our population (39 ± 13 mg, corrected for body surface area) was found not to be influenced by sex, age (19–60 years) or amounts of Ca2+, Mg2+ and Na+ excreted
3. Urine samples collected at 2 h intervals over 24 h from individuals drinking in response to thirst, contained quantities of the glycoprotein which showed high positive correlations with urine volumes, but not with Ca2+, Mg2+ or Na+ excretion
4. The amounts of urine and of the glycoprotein were correlated for individuals in anti- diuresis, induced by restriction of water intake. Relatively small amounts of glycoprotein were excreted by individuals in states of water-induced diuresis
5. The amounts of glycoprotein excreted after exercise were positively correlated with the small volumes of urine voided, but they were uninfluenced by the degree of proteinuria or of hyaline cast formation
6. The half-life for turnover of the glycoprotein in a given individual is highly variable, from a minimum of 3–7 to a maximum of 168 h.
Effects of Meclofenamate and Captopril on Renal and other Regional Vascular Beds after Mild Haemorrhage in Conscious Rabbits
Authors: Banks R. A. , Beilin L. J. , Soltys J. , Davidson L. 
Published: August 2015

1. The role of prostaglandins and angiotensin II in blood flow regulation was studied in conscious rabbits subjected to mild haemorrhage.
2. Haemorrhage caused a 13% fall in arterial pressure and a 21% fall in cardiac output, responses which were unchanged by sodium meclofenamate, an inhibitor of prostaglandin synthesis, or captopril, an inhibitor of the angiotensin converting enzyme.
3. Haemorrhage doubled plasma adrenaline and noradrenaline levels. Plasma renin activity trebled after haemorrhage and was further elevated by captopril.
4. Renal blood flow was maintained after haemorrhage alone. Meclofenamate given immediately after haemorrhage caused a 31% fall in renal blood flow. Captopril given immediately after haemorrhage caused renal vasodilation, but when given after meclofenamate augmented renal vasoconstriction.
5. Splenic vasoconstriction was seen after haemorrhage and meclofenamate, and subsequently was augmented by captopril.
6. Results suggest that prostaglandins variably modulate regional blood flow in conscious rabbits subjected to mild haemorrhage. Enhanced sympathc—adrenal activity increases reno-vascular and splenic dependence on vasodilator prostaglandins, but not that of coronary, cerebral, hepatic or adrenal circulations. Renal and splenic vasoconstriction seen with meclofenamate are not due to circulating angiotensin II.
Isolation and Characterization of a Pancreatic Elastase from Plasma of Patients with Acute Pancreatitis
Authors: Toki Naotika , Takasugi Sumiyoshi , Sumi Hiroyuki 
Published: August 2015

1. An elastase-like enzyme in plasma of patients with acute pancreatitis was purified by DEAE-cellulose column chromatography and polyacrylamide-gel disc electrophoresis.
2. In this way 0.24 mg of purified enzyme with a specific activity of 3.94 succinyl-l-alanyl-l-alanyl-l-alanyl-p-nitroanilide units/mg of protein was obtained from 10 ml of plasma.
3. The purified material was homogeneous as ascertained by sodium dodecyl sulphate/polyacrylamide-gel disc electrophoresis and had an apparent molecular weight of 24 000 as measured by gel filtration on Sephadex G-100.
4. This enzyme hydrolysed denatured casein and Congo Red—elastin as well as succinyl-l-alanyl-l-alanyl-l-alanyl-p-nitroanilide. Its amidolytic activity was inhibited by soya bean trypsin inhibitor, but not by aprotinin.
6. We propose that an elastase-like enzyme, probably different from elastase 1 or elastase 2, is liberated from the pancreas into blood during acute pancreatitis and becomes combined with α2-macroglobulin.
Effect of Acute Unilateral Renal Denervation on Intrarenal Haemodynamics and Urinary Excretion in Rats before and during Hypervolaemia
Authors: Veressa A. T. , Chong C. K. , Sonnenberg H. 
Published: August 2015

1. The possible involvement of renal nerves in the diuresis and natriuresis of blood volume expansion was studied in anaesthetized rats. Acute unilateral renal denervation caused increased excretion of fluid, sodium and potassium.
2. Renal blood and plasma flows were elevated without change in filtration rate. Intracortical blood flow distribution was not affected by the denervation.
3. Blood infusion caused diuresis, natriuresis and kaliuresis in both denervated and shamdenervated kidneys, associated with comparable initial increases in filtration and decreases in renal blood flow. No change in flow distribution was found, whether or not renal nerves were intact.
4. Although the magnitude of the excretory response to hypervolaemia was greater in denervated kidneys, the temporal pattern was identical with that of sham-operated kidneys. Our data thus do not show an effect of efferent renal nerve activity on volume natriuresis.
Sodium Balance, Fluid Homeostasis and the Renin–Aldosterone System during the Prolonged Exercise of Hill Walking
Authors: Milledge J. S. , Bryson E. I. , Catley D. M. , Hesp R. , Luff N. , Minty B. D. , Older M. W. J. , Payne N. N. , Ward M. P. , Withey W. R. 
Published: August 2015

1. The effect of 5 consecutive days of hill walking on electrolyte balance, fluid homeostasis, plasma renin activity and plasma aldosterone concentration was studied in five male subjects.
2. The 5-day exercise period was preceded by a 4-day control period and followed by a 4-day recovery period. Throughout the 13-day study subjects ate a fixed diet.
3. After 5 days of exercise subjects had retained a mean of 264 mmol (sd 85) of sodium. Plasma sodium concentration remained constant at 142.0 mmol/l (sd 5.4). This indicates an expansion of the extracellular space by 1.84 litres.
4. By the end of the exercise period there was a positive water balance of about 0.9 litre. Thus there was a net movement of 0.94 litre of fluid from the intracellular to the extracellular space.
5. Packed cell volume decreased from a mean of 43.5% to 37.9% after 5 days of exercise, indicating that about 0.9 litre of the extracellular fluid entered the vascular compartment. The remaining fluid may be responsible for the significant increase in lower leg volume.
6. During the exercise period plasma aldosterone concentration and plasma renin activity rose, and there was a highly significant correlation between these values and the sodium retention. There was also a significant correlation between sodium retention and the increase in leg volume, which suggests that oedema may be the result of prolonged exercise of this type.
Activation by Exercise of Human Skeletal Muscle Pyruvate Dehydrogenase In Vivo
Authors: Ward G. R. , Sutton J. R. , Jones N. L. , Toews C. J. 
Published: August 2015

1. The activity of pyruvate dehydrogenase in its active and inactive forms was measured in biopsy samples obtained from the vastus lateralis muscle of healthy subjects before and after exercise.
2. At rest, 40 ± 4% (mean ± sem) of the enzyme was in the active form.
3. After progressive aerobic exercise to exhaustion (n = 5), 88 ± 2·3% was in the active form.
4. After intermittent supramaximal short-term exercise (1 min exercise, 3 min rest) to exhaustion (n = 6), 60 ± 2·2% was in the active form.
5. After isometric maximal exercise of 65 ± 3·6 s duration (n = 3), only 39 ± 1% of the enzyme was in the active form.
6. Muscle glycogen depletion was greatest with intermittent exercise and least with isometric maximal exercise; in contrast, the increase in muscle lactate was least with progressive exercise (1·3 to 9·4 μmol/g), intermediate in intermittent maximal exercise (1·2 to 13·1 μmol/g) and greatest after isometric exercise (1·8 to 17·6 μmol/g). There were no significant differences between the three studies in the changes in lactate/pyruvate ratios.
7. In three subjects who exercised with one leg, activation of the enzyme was twice as great in the exercised as in the inactive leg.
8. The ratio of active to total enzyme in biopsies of resting muscle was greater in four well-trained athletes than in four untrained control subjects (70% compared with 41% respectively).
9. The activation of pyruvate dehydrogenase appears to play an important part in regulating the use of glycogen and glucose during exercise in man.
Cardiac Output Measured by Transthoracic Impedance Cardiography at Rest, during Exercise and at Various Lung Volumes
Authors: Edmunds A. T. , Godfrey S. , Tooley Marion 
Published: August 2015

1. Cardiac output measured by transthoracic impedance cardiography has been compared with simultaneous measurements made by the indirect Fick CO2 rebreathing method in nine adults and 14 children. All were healthy normal volunteers. Sixty-six comparisons were made at rest and during steady exercise at work loads up to 100 W.
2. Impedance measurements of cardiac output were consistently higher than indirect Fick measurements of cardiac output, but after application of a correction factor related to packed cell volume there was close correlation between the results obtained by the two methods (r = 0·94).
3. The mean coefficient of variation of impedance measurements of cardiac output was 13% at rest and 5% during steady-state exercise.
4. Changes of lung volume due to breath holding or resulting from addition of an expiratory resistance did not affect the measurement of cardiac output by impedance.
5. Transthoracic impedance cardiography is a rapid, non-invasive technique for measurement of cardiac output. It requires very little active co-operation from the subject. The method would probably give reliable results for patients with respiratory illnesses such as acute asthma or bronchiolitis, during which changes of lung volume may be expected to occur.
Effects of Inhalation of β-Sympathomimetic and Atropine-Like Drugs on Airway Calibre in Normal Subjects
Authors: MacNee W. , Douglas N. J. , Sudlow M. F. 
Published: August 2015

1. Bronchodilatation was produced in eight normal subjects by inhalation, on separate occasions, of the atropine-like drug ipratropium bromide (0·16 mg by pressurized inhaler; 1 mg nebulized) and the β-sympathomimetic salbutamol (0·8 mg by pressurized inhaler; 5 mg nebulized).
2. Mean specific airways conductance (sGaw) increased from a mean value of ·185 ± se 0·002 to 0·292 ± 0·023 s−1 kPa−1 after ipratropium bromide, and from 0·184 ± 0·020 to 0·303 ± 0·026 s−1 kPa−1 after salbutamol. These increases in sGaw were not significantly different from each other.
3. During both maximal and partial expiratory flow volume manoeuvres similar increases in flow rates were produced by each drug, at all lung volumes, from 40 to 20% of vital capacity.
4. Changes in maximal and partial flow volume curves after washout of lung air with helium/oxygen (4:1) were measured before and after each drug. Flow rates increased in all subjects and the percentage increase in maximum flow when helium was breathed was not significantly different, when repeated after each drug.
5. Thus our results suggest that salbutamol and ipratropium have similar sites of action, both affecting both large and small airways, and produce similar degrees of bronchodilatation. This is supported by our results after the helium/oxygen breathing, where the lack of change in density dependence of maximal flow suggests that there was no change in the distribution of airways resistance after the drugs.
Hyperoxaluria in Idiopathic Calcium Stone Disease: Further Evidence of Intestinal Hyperabsorption of Oxalate
Authors: Marangella M. , Fruttero B. , Bruno M. , Linari F. 
Published: August 2015

1. Seventeen healthy controls and 63 patients with idiopathic calcium stone disease of the urinary tract were investigated for urinary calcium and oxalate excretion and for [14C]oxalate intestinal absorption.
2. Under comparable controlled dietary intake a significant increase in calcium excretion was found in patients with stone disease. Oxalate excretion and [14C]oxalate intestinal absorption were mildly but not significantly increased. When patients with stone disease were subdivided into normocalciuric and hypercalciuric subjects, oxalate excretion and [14C]oxalate absorption were significantly increased in the latter. There was a significant direct relationship between calcium excretion and both oxalate excretion and [14C]oxalate absorption.
3. [14C]Oxalate absorption increased significantly in 22 stone-formers when dietary calcium was changed from normal to low.
4. The kinetics of [14C]oxalate intestinal absorption showed that the main difference between normocalciuric and hypercalciuric subjects occurred within the first 6 h after the oxalate-labelled meal.
5. These results confirm that mild hyperoxaluria is a frequent feature of idiopathic calcium stone disease even when patients and controls are studied under controlled dietary conditions. Our data are consistent with the hypothesis that hyperoxaluria is secondary to calcium hyperabsorption and is upper intestinal in origin.
Regulation of Brain Renin: Evidence for an Independent Brain Renin
Authors: Dzau Victor J. , Sands Kenneth E. 
Published: August 2015

1. We examined the effects of various physiological states on systemic and brain renin activities. Activation of the systemic renin-angiotensin system (RAS) by renal ischaemia, captopril or continuous renin infusions had no effect on whole brain or pituitary renin activities. Suppression of circulating renin by bilateral nephrectomy or antirenin antibody injection did not influence brain renin.
2. Brain or pituitary renin activities remained unchanged with various endocrine-metabolic disorders such as hypo- or hyper-thyroidism, diabetes and hypophysectomy.
3. Treatment with reserpine or propranolol resulted in significant decrease in brain and pituitary renin levels.
4. We conclude that brain renin activity appears to be generally independent of the systemic RAS. Inhibition of sympathetic activity, however, resulted in suppression of brain renin, suggesting a close interaction between the two systems.
Brain Angiotensin II Does Not Mediate the Cardiovascular Response to Cerebroventricular Administration of Hypertonic Sodium Chloride Solution in Dogs
Authors: Takishita Shuichi , Ferrario Carlos M. 
Published: August 2015

1. A possible interaction between an osmotic stimulus and brain angiotensin II was studied in anaesthetized dogs by measuring the changes in arterial pressure, heart rate and renal sympathetic nerve activity during a brain ventricular injection of hypertonic NaCl solution before and after pretreatment with either captopril or [Sar1, Ile8]angiotensin II.
2. Mild pressor responses accompanied by a reflex decrease in renal sympathetic nerve activity were a characteristic before pretreatment, but after baroreceptor denervation the cardiovascular response to hypertonic NaCl solution doubled and the activity increased. These changes were prevented by intravenous pretreatment with hexamethonium chloride.
3. Brain ventricular injection of captopril slightly augmented pressor and tachycardia effects of hypertonic NaCl solution.
4. Blockade of central angiotensin II receptors with [Sar1, Ile8]angiotensin II was without effect.
5. It is concluded that central administration of hypertonic NaCl solution in baroreceptor-denervated dogs produces marked pressor responses due to increased sympathetic nerve activity via mechanisms not related to the brain renin-angiotensin system.
Interaction of Metoprolol, Propranolol and Atenolol with Cimetidine
Authors: Kirch W. , Spahn H. , Köhler H. , Mutschler E. 
Published: August 2015

1. Pharmacokinetics of metoprolol, propranolol and atenolol were investigated in six healthy volunteers after 7 days of oral monotherapy with these drugs and after 7 days concurrent administration, with each of these β-adrenoceptor antagonists with cimetidine.
2. Cimetidine did not interact with atenolol, whereas mean peak plasma concentrations of metoprolol were increased by 70%, and those of propranolol by 95% with concurrent administration of cimetidine (P &lt; 0.05).
3. The area under the plasma concentration-time curve for propranolol and metoprolol was similarly increased (P &lt; 0.05).
Effect of Long-Term, Once-Daily Administration of Atenolol, Metoprolol, Pindolol and Slow-Release Propranolol on Ambulatory Blood Pressure and its Variability
Authors: Floras J. S. , Jones J. V. , Hassan M. O. , Sleight P. 
Published: August 2015

1. Twenty-four-hour intra-arterial blood pressure recordings were made before and after chronic β-receptor blockade in 34 patients with essential hypertension.
2. Subjects were randomized in double blind fashion to either atenolol, metoprolol, pindolol or slow-release propranolol.
3. Drugs were administered in a once-daily variable dose regimen for a period of 3–8 months (mean 5.0 ± sd 1.4).
4. All four drugs reduced blood pressure significantly 24 h after the last dose but there were considerable differences in control when each intervening hour was assessed separately.
5. Not all β-receptor blockers in conventional formulations are equally effective as antihypertensive agents over 24 h when taken once daily.
Erythrocyte Sodium and Potassium in Patients with Hypokalaemia
Authors: Cumberbatch M. , Morgan D. B. 
Published: August 2015

1. The erythrocyte content of sodium and of potassium were measured in 231 unselected patients with hypokalaemia, and together with net ouabain-sensitive sodium efflux in patients with severe hypokalaemia, before (20 patients) and during potassium repletion (14 patients).
2. The erythrocytes of the patients with hypokalaemia compared with control subjects had on average an increase in sodium content, a decrease in potassium content and a reduction in the rate constant of ouabain-sensitive sodium efflux. All three changes had a similar curvilinear relation to the concentration of potassium in plasma with relatively little change in the measured variable unless the plasma potassium was very low.
3. There was a similar curvilinear relation between the final sodium and potassium content of normal erythrocytes and the potassium concentration of the medium in which they were incubated for 48 h in vitro.
4. These results suggest that the changes in the sodium and potassium content of erythrocytes in hypokalaemia are due to a direct inhibiting effect of the hypokalaemia on the activity of the sodium pump.
5. In many patients with hypokalaemia of moderate degree the increase in erythrocyte sodium content was less than expected from the effect in vitro of a low extracellular potassium concentration. This finding suggests that a compensatory change, presumably an increase in the number of sodium pumps, is a common event even in moderate hypokalaemia.
Reversible Acid Activation of Amniotic Fluid Inactive Renin
Authors: Franks Robert C. , Bodola Francis , Renthal Robert D. , Hayashi Robert H. 
Published: August 2015

1. Inactive renin was isolated from human amniotic fluid by chromatography with DEAE-cellulose, pepstatin-aminobutyl-agarose, octylagarose and Cibacron Blue F3GA columns.
2. Before and after isolation from amniotic fluid, inactive renin could be activated by incubation with pepsin and by dialysis to pH 3.3, and the acid activation could be reversed by subsequent incubation at pH 7.4 and 37°C.
3. Inactive renin was not activated by procedures expected to dissociate renin from an inhibitor.
4. The results suggest a pH-dependent conformational change as the mechanism of reversible acid activation of inactive renin in amniotic fluid.
5. There are chromatographic and activation similarities of inactive renin from human plasma, kidney and amniotic fluid.
Lactic Acidosis and the Cardiovascular System in the Dog
Authors: Arieff Allen I. , Gertz Edward W. , Park Robert , Leach Will , Lazarowitz Virginia C. 
Published: August 2015

1. Lactic acidosis is a clinical syndrome characterized by metabolic acidaemia (pH &lt; 7.25) and hyperlactaemia (lactate &gt;5 mmol/l). Many patients with type B lactic acidosis have no evidence of tissue hypoxia or myocardial dysfunction when first evaluated. Although it is considered that cardiac dysfunction is secondary to the systemic effects of lactic acidosis, the reverse may sometimes be true. To evaluate this possibility, studies were carried out in 43 dogs consisting of a control group and three groups which had hyperlactataemia and metabolic acidaemia related to either: (1) phenformin infusion; (2) hepatectomy; (3) lactic acid infusion. Serial studies of cardiac function, as well as measurements of GFR (glomerular filtration rate) and hepatic portal vein (HPV) blood flow, were carried out.
2. in dogs infused with phenformin for 99 min, the arterial pH, lactate, bicarbonate, heart rate and mean blood pressure (BP) were normal. However, there was significant deterioration (P &lt; 0.01) in several indices of cardiac function, including the peak positive dP/dt, cardiac output, LVEDP (left ventricular end-diastolic pressure) and percentage extraction of oxygen and lactate by the heart. After 3 h of phenformin, the blood lactate exceeded 5 mmol/l and there were further significant decrements (P &lt; 0.01) in cardiac output, LVEDP and dP/dt, as well as BP and heart rate. in dogs subjected to hepatectomy, the decrement in cardiac output was similar to that with phenformin infusion. However, in animals infused with lactic acid, despite a similar blood pH and lactate, cardiac output was unaffected. Although percentage myocardial oxygen extraction declined in phenformin-infused animals, there was a concomitant increase in coronary sinus blood flow such that myocardial oxygen utilization was probably unaltered.
3. Thus, in certain types of experimental type B lactic acidosis, myocardial dysfunction may be a primary event, with other associated systemic manifestations being secondary.
The Use of 4-Aminobenzoic Acid as a Marker to Validate the Completeness of 24 H Urine Collections in Man
Authors: Bingham Sheila , Cummings J. H. 
Published: August 2015

1. At the present time there is no method whereby the completeness of 24 h urine collections can be accurately assessed when clinical studies are undertaken. The suitability of 4-aminobenzoic acid (PAB) given with meals as a marker for completeness of urine collections was therefore investigated.
2. When a single dose of 80 mg of PAB was given to four volunteers 93% was recovered in the urine in 5 h.
3. Eight volunteers living in a calorimeter, where complete urine collection could be guaranteed, were given various doses of PAB divided up throughout the day. 88 ± 5% was excreted in the urine over a 24 h period. Urine excretion and oral dose were directly related.
4. Thirty-three reliable free-living volunteers eating their normal diet took 80 mg of PAB with meals (240 mg/day). Mean urine recovery over the 24 h period was 223 ± 9 mg, or 93 ± 4% of the administered dose. The range in individual recovery from maximum to minimum was 15%, compared with 75% for creatinine excretion per kg fat-free mass.
5. PAB is a safe marker of the completeness of 24 h urine collections. Any collection containing less than 205 out of 240 mg (85%) of PAB, given as 80 mg with each of three meals, is probably incomplete.