bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inter-Relationships of Carbonate, Phosphate, Monohydrogen Phosphate, Calcium, Magnesium and Sodium in Uraemic Bone: Comparison of Dialysed and Non-Dialysed Patients
Authors: Pellegrino E. D. , Biltz R. M. , Letteri J. M. 
Published: August 2015

1. Chemical and morphological features of uraemic bone disease were studied by comparison of bone composition in 44 patients with uraemia (12 dialysed and 32 non-dialysed) and 36 control subjects. The significant changes included decreased bone mineral carbonate associated with calcium, a concomitant increase in phosphate, and an increase in magnesium. There was also an increase in osteoid and a reduction in the specific gravity of the compact bone.
2. The most marked changes in bone composition were observed in patients with uraemia of more than 1 year's duration, who had been dialysed. Bone mineral sodium concentrations were not significantly altered in any group.
3. The changes in bone mineral composition appeared to be the result of several simultaneous and/or successive mechanisms: (i) loss of fixed base, calcium carbonate; (ii) replacement of carbonate by phosphate; (iii) the addition of immature bone mineral, which contains high concentrations of phosphate and relatively low concentrations of carbonate.
4. These observations are consistent with earlier views of the bone salt as an indefinite calcium/phosphate/carbonate complex. Variations in bone composition may arise from a reciprocal relationship between phosphate and carbonate. The bone mineral analogue that best explains these variations in bone composition is octacalcium phosphate carbonate [Ca4(PO4)2(HPO4)x(CO3)1-x,zH2O].
Circulating Inhibitor of Sodium—Potassium-Activated Adenosine Triphosphatase after Expansion of Extracellular Fluid Volume in Rats
Authors: Gonick H. C. , Kramer H. J. , Paul W. , Lu E. 
Published: August 2015

1. Serum was collected from normal rats and from rats volume-expanded with isotonic sodium chloride solution.
2. The serum was fractionated by gel filtration on Sephadex G-25 and each fraction was tested for inhibitory activity against sodium—potassium-activated adenosine triphosphatase prepared from rat kidney homogenate.
3. A single low-molecular-weight fraction, eluting after the salts and after exogenously added lysine-vasopressin, had significantly greater enzyme inhibitory activity when obtained from serum of volume-expanded animals than from control serum.
4. As this fraction has been shown in previous independent studies to contain a natriuretic factor, it may be concluded that one property of this factor is the ability to inhibit sodium—potassium-activated adenosine triphosphatase.
Alterations in the Activity of Enzymes of Haem Biosynthesis in Lead Poisoning and Acute Hepatic Porphyria
Authors: Campbell B. C. , Brodie M. J. , Thompson G. G. , Meredith P. A. , Moore M. R. , Goldberg A. 
Published: August 2015

1. The activities of six of the enzymes of haem biosynthesis have been assayed in peripheral blood from patients with lead poisoning, acute intermittent porphyria or hereditary coproporphyria.
2. Compared with normal subjects the lead-poisoned subjects had highly significant depression of δ-aminolaevulinate dehydratase, coproporphyrinogen oxidase and ferrochelatase.
3. Lead-poisoned subjects had highly significant elevation of δ-aminolaevulinate synthase activity.
4. δ-Aminolaevulinate synthase activity was inversely related to the haemoglobin concentration.
5. Increased δ-aminolaevulinate synthase and decreased δ-aminolaevulinate dehydratase activity are also found in acute intermittent porphyria.
6. Increased δ-aminolaevulinate synthase, normal porphobilinogen deaminase and uroporphyrinogen decarboxylase and decreased coproporphyrinogen oxidase are found in both lead poisoning and hereditary Coproporphyria.
7. These enzyme changes explain the recognized patterns of porphyrins and porphyrin precursors in blood and urine in these conditions.
Leg Blood Flow and Central Circulation at Various Blood Volumes: A Peroperative Study of Nine Patients with Varicose Veins
Authors: Brismar B. , Cronestrand R. , Jorfeldt L. , Juhlin-Dannfelt A. 
Published: August 2015

1. In a group of nine middle-aged patients undergoing varicose vein surgery, cardiac output, right atrial, pulmonary arterial and capillary pressures, and leg blood flow were measured after induction of general anaesthesia but before operation, and also during operation before and after blood substitution.
2. Under anaesthesia, the mean preoperative blood flows in the superficial and common femoral arteries were 160 ml/min and 280 ml/min respectively. These flows are comparable with those obtained in other studies under similar conditions but lower than values obtained in conscious subjects. During the operation the leg blood flow decreased by 24%. As cardiac output remained unchanged, the fractional leg blood flow fell. After transfusion of 900 ml of blood the leg blood flow doubled.
3. It is concluded that anaesthesia, surgical trauma and variations in blood volume greatly influence the leg blood flow and that an adequate substitution of operative blood loss is of utmost importance to achieve an optimum peripheral circulation.
Effect of 30% Oxygen on Local Matching of Perfusion and Ventilation in Chronic Airways Obstruction
Authors: Eiser Noemi M. , Jones Hazel A. , Hughes J. M. B. 
Published: August 2015

1. Sixteen patients with chronic bronchitis and airways obstruction were given radioactive nitrogen (13N) by intravenous injection and by inhalation, while breathing air and after 10–20 min breathing 30% oxygen. The clearance of 13N from four zones of each patient's whole lung field was monitored.
2. The 13N clearance of each region in these patients with chronic bronchitis was much slower than in normal subjects. Oxygen breathing produced a significant delay in the clearance of intravenously administered 13N in 23 zones in 10 patients but no systematic change in clearance after inhaled 13N.
3. With inhalation of 30% oxygen there was no significant change in the mean minute ventilation, tidal volume or arterial Pco2.
4. The results suggest that local hypoxic vasoconstriction is present in some patients on breathing air and that this is relieved by 30% oxygen, resulting in a diversion of local blood flow from well-ventilated to more poorly ventilated areas. The fall in V̇A/Q̇ on 30% oxygen is insufficient to increase arterial Pco2.
Effect of α-Methyldopa on the Pulmonary Vascular Changes Induced by Chronic Hypoxia in Rats
Authors: Suggett A. J. , Herget J. 
Published: August 2015

1. Groups of young rats were kept in a hypoxic chamber or in air as control animals for 28 days.
2. Hypoxic and control animals were treated with either α-methyl-3,4-dihydroxyphenylalanine (α-methyldopa) or distilled water.
3. α-Methyldopa significantly reduced the increase in pulmonary artery pressure and right ventricular hypertrophy induced by chronic hypoxia and partially prevented the histological changes in the small pulmonary vessels.
Decreased Plasma Renin Activity and Renin Release in Rats with Phaeochromocytoma
Authors: Fray J. C. S. , Mayer P. V. H. 
Published: August 2015

1. We have examined the response of renin to chronic low and high sodium chloride intake in rats with transplanted phaeochromocytoma.
2. Phaeochromocytoma suppressed the usual elevated plasma renin activity observed during sodium deprivation.
3. Studies in isolated perfused kidneys indicated that sodium-deprived phaeochromocytoma rats released substantially less renin than sodium-deprived control rats despite an almost identical renal renin content in both sets of animals. In addition, low perfusion pressure (50 mmHg) failed to stimulate renin release in kidneys from these phaeochromocytoma rats.
4. Additional experiments demonstrated that chronic sodium chloride loading suppressed plasma renin activity, renin content and renin release in both phaeochromocytoma and control rats. Both sodium-loaded phaeochromocytoma and sodium-loaded control rats were unresponsive to low perfusion pressure.
5. We conclude that noradrenaline-secreting phaeochromocytoma impairs the response of plasma renin activity in the rat by inhibiting renin release. We also conclude that chronic sodium chloride loading has a similar effect, but the mechanisms remain to be determined.
Protein Turnover, Synthesis and Breakdown before and after Recovery from Protein-Energy Malnutrition
Authors: Golden M. H. N. , Waterlow J. C. , Picou D. 
Published: August 2015

1. Rates of total protein turnover, synthesis and breakdown were measured in five children before and after recovery from severe protein-energy malnutrition and while receiving 0·6 g of protein and 397 kJ day−1 kg−1.
2. These rates were calculated after giving doses of [15N]glycine every 2 h along with the feeds and measuring the rate of excretion of [15N]urea in urine.
3. Malnourished children had significantly lower rates of protein turnover, synthesis and breakdown than after they had recovered.
4. During recovery from protein-energy malnutrition, two children on a daily intake of 1·2 g of protein and 605 J/kg body weight, had rates of protein turnover, synthesis and breakdown that were twice as great as those found on admission and higher than after recovery.
5. On the study diet the malnourished children maintained their weight while the recovered children lost weight; the apparent nitrogen balance was more positive in the malnourished children.
6. In recovered children, the rate of protein synthesis was unchanged over a wide range of protein intake, whereas the rate of protein breakdown appeared to rise with a reduction in protein intake.
Effects of Analgesics and Related Compounds on Renal Metabolism in Rats
Authors: Tange J. D. , Ross B. D. , Ledingham J. G. G. 
Published: August 2015

1. The metabolic effects of p-aminophenol have been compared with those of paracetamol and other analgesics in studies of rat liver and kidney in vitro.
2. p-Aminophenol injected into rats inhibited gluconeogenesis from lactate in renal cortical tubules, but not in isolated hepatocytes, and reduced kidney ATP content without affecting the ATP content of liver. Perfused kidneys from rats previously injected with p-aminophenol showed a 50% reduction of ATP content, severe inhibition of Na+ reabsorption and reduction of inulin clearance without significant inhibition of gluconeogenesis from lactate.
3. Paracetamol, p-phenetidine, phenazone and aspirin, when given intravenously to rats, had no effect on renal tubular glucose synthesis from lactate or pyruvate. Paracetamol and aspirin both slightly inhibited renal glucose synthesis from several different substrates when added directly to tubules.
4. Paracetamol (4 mmol/l) inhibited glucose synthesis from lactate and other substrates by 50% or more in isolated hepatocytes. Glucose synthesis from lactate was inhibited 30% by concentrations of paracetamol as low as 0–5 mmol/l.
5. These results indicate that p-aminophenol is a potent inhibitor of proximal tubular function, with its main site of action the inhibition of ATP synthesis and energy production, and they confirm the primary hepatotoxic effect of paracetamol.
Abnormalities in Enzymes Involved in Catecholamine Synthesis and Catabolism in Phaeochromocytoma
Authors: Jarrott B. , Louis W. J. 
Published: August 2015

1. The activities of the enzymes involved in catecholamine synthesis, tyrosine hydroxylase, aromatic amino acid decarboxylase and dopamine β-hydroxylase, were markedly enhanced in homogenates of phaeochromocytoma compared with human adrenal medulla homogenates measured under optimum substrate concentrations.
2. It was demonstrated in fresh tumour slices that the rate of formation of dopamine (3,4-dihydroxyphenethylamine) from tyrosine was much slower than the rate of formation of dopamine from dopa (3,4-dihydroxyphenylalanine) (suggesting that tyrosine hydroxylase was the rate-limiting enzyme in noradrenaline synthesis in phaeochromocytoma) and that the tyrosine hydroxylation step was still susceptible to end-product inhibition by catecholamines.
3. It is suggested that catecholamine overproduction in phaeochromocytoma is due to the increased activities of catecholamine synthetic enzymes rather than to an insensitivity of tyrosine hydroxylase to end-product inhibition.
4. The activities of the enzymes involved in catecholamine catabolism, monoamine oxidase and perhaps catecholamine O-methyltransferase, were reduced in phaeochromocytoma. This finding provides a biochemical basis for the previous published observations of nonexocytotic release of catecholamines in these tumours. Thus excess amounts of newly synthesized noradrenaline which cannot be stored in the filled catecholamine storage vesicles may not be degraded owing to the reduced monoamine oxidase activity and could diffuse from the phaeochromocytoma into the circulation.
Subcellular Localization of Enterokinase in Human Duodenal Mucosa
Authors: Lobley R. W. , Franks Ruth , Holmes R. 
Published: August 2015

1. Specimens of human duodenal mucosa were obtained at duodenotomy. Superficial mucosal scrapings were homogenized in isotonic sucrose solution and fractionated by differential centrifugation. The distribution of organelles among the subcellular fractions was monitored by assay of suitable marker enzymes.
2. Enterokinase was recovered predominantly in the nuclear + brush-border fraction and 80% of the total activity was found to be particulate; approximately 20% of the enzyme was present in the soluble fraction, compared with 1% of the brush-border markers sucrase and alkaline phosphatase.
3. The brush-border-containing fraction was subfractionated by treatment with hypertonic Tris followed by differential and density gradient centrifugation. Enterokinase was distributed among the subfractions in parallel with brush-border markers and was concentrated in a subfraction which was highly enriched in microvillous membranes.
4. It was concluded that enterokinase is localized primarily to the microvillous membrane of the epithelial cell brush border in man, but that in addition a proportion of the enzyme may be present in a soluble or easily released form in the duodenal mucosa.
Role of Cyclic AMP in the Natriuresis of Extracellular Fluid Volume Expansion in the Dog
Authors: Friedler R. M. , Descoeudres C. , Kurokawa K. , Kreusser W.-J. , Massry S. G. 
Published: August 2015

1. The effect of extracellular volume expansion (ECVE) on renal production of cyclic AMP was evaluated in 19 thyroparathyroidectomized dogs. ECVE was produced by the infusion of Ringer bicarbonate solution at a rate of 2 ml min−1 kg−1 body weight; cyclic AMP was measured in plasma obtained from the aorta and renal vein and in the urine.
2. During the natriuresis of ECVE urinary excretion of cyclic AMP, the clearance of cyclic AMP, net nephrogenous cyclic AMP added both to urine and to the renal vein and hence total nephrogenous cyclic AMP increased significantly.
3. This rise in net production of cyclic AMP and a significant natriuresis by the kidney persisted for 60–90 min after discontinuation of active ECVE and return of renal plasma flow to normal.
4. The results support the notion that an increase in the production of cyclic AMP by the kidney may play a role in the natriuresis of ECVE.
The Renin-Aldosterone System in Exaggerated Natriuresis of Essential Hypertension
Authors: Pedersen E. B. , Kornerup H. J. 
Published: August 2015

1. The effect of intravenous loading with 500 ml of sodium chloride solution (50 g/l) on plasma renin concentration, plasma aldosterone concentration, urinary sodium excretion and mean blood pressure was studied in 15 young patients with mild essential hypertension and 10 healthy normotensive control subjects.
2. Plasma renin concentration and plasma aldosterone concentration were suppressed to the same degree during loading in both the hypertensive and normotensive groups. Urinary sodium excretion was significantly higher in the hypertensive patients than in the normotensive subjects. Mean blood pressure increased slightly in both groups.
3. Plasma renin concentration and plasma aldosterone concentration were significantly correlated in both groups before sodium loading. The increase in urinary sodium excretion was significantly correlated to the suppression of plasma aldosterone concentration in the hypertensive, but not in the normotensive, group. No correlation was found between changes in urinary sodium excretion and changes in plasma renin concentration or mean blood pressure.
4. The results indicate that the suppressibility of the renin—aldosterone system by hyperosmotic sodium chloride solution is normal in young patients with mild essential hypertension. It is suggested that the changes in plasma aldosterone concentration induced by sodium loading might be involved in the regulation of exaggerated natriuresis in essential hypertension.
Increase in Serum Ionized Calcium during Exercise
Authors: Nielsen S. Pors , Christiansen T. Falch , Hartling O. , Trap-Jensen J. 
Published: August 2015

1. Normal subjects showed an average increase in serum ionized calcium (Ca2+) concentration of 0·11 mmol/l in peripheral venous blood 10 min after onset of bicycle exercise at 70% of maximum aerobic capacity. The corresponding mean rise in serum total calcium concentration was 0·21 mmol/l.
2. The change in serum Ca2+ as result of acidification was studied in 20 normal subjects by carbon dioxide equilibration in vitro followed by measurement of serum Ca2+. The log serum Ca2+ was inversely proportional to serum pH.
3. The Δlog serum Ca2+/ΔpH in vitro was similar to the Δlog serum Caa+/ΔpH in vivo during exercise, this ratio, however, being somewhat greater during the first minute of exercise.
4. Serum Ca2+ returned to normal values about 20 min after stopping exercise as the pH returned to normal, but the fall immediately after stopping exercise was more pronounced than that due to the change in pH, as predicted from the studies in vitro.
5. Blood lactate concentration rose from 0·86 to 8·41 mmol/l after 10 min exercise, but the rise in blood lactate during exercise was slower than the rise in serum Ca2+. Also the fall during the recovery period was delayed compared with the fall in serum Ca2+.
6. It is suggested that the rise in serum Ca2+ during severe muscular exercise might be important for the physiological adaptations during work, and for bone metabolism.
Pulmonary Blood Volume in Chronic Bronchitis
Authors: Raffestin B. , Valette H. , Hebert J. L. , Duhaze P. , Lockhart A. 
Published: August 2015

1. Pulmonary blood volume was measured in 39 patients with severe chronic bronchitis, of whom 29 had recently recovered from an acute exacerbation. Pa,o2 was below 10·3 kPa in all but five patients, Pa,co2 was above 5·6 kPa in 26 cases, and pulmonary artery mean pressure was above 20 mmHg in 29 cases. Pulmonary blood volume was measured with the double-injection—single-sampling technique using Indocyanine Green and pulmonary wedge injection.
2. Pulmonary blood volume in the 39 patients was significantly lower (343 ± 95 ml) than in a group of 16 normal subjects (469 ± 117 ml) studied previously by the same method. There was no correlation between pulmonary blood volume and driving pressure across the pulmonary circulation, or between pulmonary blood volume and Pa,o2.
3. Breathing 26–29% oxygen in 19 patients caused no significant changes in either pulmonary blood volume or pulmonary vascular resistance. Therefore the reduced pulmonary blood volume could not be attributed to hypoxic pulmonary vasoconstriction.
4. The finding of a diminished pulmonary blood volume in chronic bronchitis is best explained by a loss of pulmonary vessels. Pulmonary blood volume was not correlated with total lung capacity nor with the residual volume/total lung capacity ratio, nor was it significantly higher in the 16 patients with normal total lung capacity (352 ± 73 ml) than in the 23 patients with a total lung capacity greater than 110% of normal (331 ± 110 ml). There was therefore no correlation between the amount of emphysema and the reduction in pulmonary blood volume.
Intracellular Free Amino Acids in Muscle Tissue of Patients with Chronic Uraemia: Effect of Peritoneal Dialysis and Infusion of Essential Amino Acids
Authors: Bergström J. , Fürst P. , Norée L.-O. , Vinnars E. 
Published: August 2015

1. Free amino acids were determined in the plasma and in the muscle tissue of 14 patients with chronic uraemia; eight were not on dialysis and six were having regular peritoneal dialysis. The concentration of each amino acid in muscle water was calculated with the chloride method.
2. In both groups of patients there were low intracellular concentrations of threonine, valine, tyrosine and carnosine, and high glycine/valine and phenylalanine/tyrosine ratios. Both groups of patients had increased amounts of 1- and 3-methylhistidine in plasma and in muscle water.
3. The non-dialysed patients had low intracellular concentrations of lysine, and the dialysed patients had high intracellular concentrations of lysine, isoleucine, leucine and of some of the non-essential amino acids.
4. After peritoneal dialysis for 22 h, the plasma concentration of several amino acids decreased but the intracellular concentrations of most amino acids did not change significantly.
5. Intravenous administration of essential amino acids and histidine during the last 4 h of dialysis increased in muscle the total free amino acids, the ratio of essential to non-essential amino acids and the valine and phenylalanine concentrations.
6. The results demonstrated that the plasma and muscle concentrations of several amino acids are grossly abnormal in chronic uraemia. Non-dialysed and dialysed patients exhibit important differences, especially in the intracellular amino acid patterns. Infusion of essential amino acids may result in enhancement of protein synthesis.
Hypertension Induced by Prolonged Intracoronary Administration of Dobutamine in Conscious Dogs
Authors: Liard J.-F. 
Published: August 2015

1. In order to determine if a sustained increase in cardiac output can lead to hypertension, seven conscious dogs were given a continuous infusion of dobutamine, a powerful stimulant of cardiac inotropism, into the left coronary artery for a 7 day period while arterial pressure, cardiac output (electromagnetic flowmeter) and heart rate were measured.
2. The infusion technique (1·5 × 10−8 mol min−1 kg−1, intracoronary) was selected after short-term experiments showed that it increased cardiac output more effectively than intravenous infusion at the same rate.
3. The rise in cardiac output elicited by intracoronary infusion of dobutamine was largest during the first 6 h of the 7 days administration, at which time calculated peripheral resistance was decreased. Subsequently, cardiac output returned progressively toward its control value whereas mean arterial pressure remained elevated (by an average of 20–25 mmHg) and peripheral resistance increased significantly.
4. Measurements of blood and extracellular fluid volumes as well as plasma renin activity indicated that these factors were not involved in the blood pressure increase.
5. When the infusion was ended, arterial pressure fell rapidly but peripheral resistance remained elevated during the first 6 h. Cardiac output fell after 2 and 6 h to a value below that of the pre-infusion control. After 1 day and subsequently, blood pressure became normal, as did the peripheral resistance and cardiac output.
6. Both at the onset and offset transients of this model of hypertension, changes in cardiac output preceded changes in peripheral resistance. These experiments may give experimental support to the concept of cardiogenic hypertension.