bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzyme Activities in Human Liver Biopsies: Assay Methods and Activities of Some Lysosomal and Membrane-Bound Enzymes in Control Tissue and Serum
Authors: Seymour Carol A. , Peters T. J. 
Published: August 2015

1. Highly sensitive techniques are described for the assay of plasma membrane (5′-nucleotidase, alkaline phosphatase), microsomal (neutral α-glucosidase, leucyl-2-naphthylamidase) and biliary canalicular (γ-glutamyltransferase) enzymes and for nine acid hydrolases (acid phosphatase, phosphodiesterase, β-glucosidase, α-glucosidase, α-galactosidase, β-galactosidase, α-mannosidase, N-acetyl-β-glucosaminidase, β-glucuronidase) in human liver.
2. Optimum and specific assay systems have been developed which give linear kinetics for all enzymes.
3. The range of enzyme activities in samples of human liver, obtained by closed needle biopsy, and in sera have been determined.
Factors affecting angiotensin II concentrations in the human infant at birth
Authors: Pipkin Fiona Broughton , Symonds E. M. 
Published: August 2015

1. A radioimmunoassay for the measurement of angiotensin II in 1 ml of plasma has been developed and used to measure angiotensin II in maternal peripheral, cord venous and cord arterial blood in 45 patients at delivery.
2. In babies delivered vaginally, cord venous and cord arterial concentrations of angiotensin II were significantly higher than maternal venous blood concentrations. There was a significant relationship between both cord venous and cord arterial concentrations and maternal concentrations of angiotensin II.
3. Cord venous concentrations of angiotensin II were significantly greater than those in cord arterial blood in babies delivered vaginally but not in those delivered by lower-segment Caesarean section. This suggests the possibility that, during labour, the placenta may contribute to foetal concentrations of angiotensin II.
4. Maternal and cord venous concentrations of angiotensin II were significantly higher in patients with hypertensive disease of pregnancy than in those who had remained normotensive throughout pregnancy.
5. Cord venous concentrations of angiotensin II increased significantly with increasing duration of the second stage of labour.
Intrarenal Distribution of Plasma Flow in Cirrhosis as Measured by Transit Renography: Relationship with Plasma Renin Activity, and Sodium and Water Excretion
Authors: Wilkinson S. P. , Smith I. K. , Clarke M. , Arroyo V. , Richardson J. , Moodie H. , Williams R. 
Published: August 2015

1. The intrarenal distribution of plasma flow was determined with a technique based on the analysis of the transit time of sodium o-[131I]-iodohippurate through the kidney in 43 patients with cirrhosis with near-normal total renal perfusion.
2. Twenty-five of the patients had an abnormal pattern of transit times, suggesting a redistribution of plasma flow from outer cortical to juxtamedullary nephrons.
3. Plasma renin activity ranged from below normal to six times normal and high values were found only in patients showing an abnormal pattern of transit times. The latter was also found to be related to sodium retention and a reduced renal capacity to excrete free water.
Protein Metabolism in Human Neonates: Nitrogen-Balance Studies, Estimated Obligatory Losses of Nitrogen and Whole-Body Turnover of Nitrogen
Authors: Pencharz P. B. , Steffee W. P. , Cochran W. , Scrimshaw N. S. , Rand W. M. , Young V. R. 
Published: August 2015

1. Aspects of nitrogen metabolism in the human neonate were assessed in one full-term infant and six premature infants by means of nitrogen-balance measurements, estimates of obligatory nitrogen losses and determinations of whole-body nitrogen turnover.
2. Our data indicate that the mean protein requirement for maintenance is 1·1 g of protein day−1 kg−1 and that 3·8 g of protein day−1 kg−1 should be sufficient for adequate growth in healthy premature babies.
3. The mean obligatory urinary, faecal and total nitrogen losses were estimated to be 24, 106 and 145 mg day−1 kg−1 respectively. These figures are compared with published values for older infants, and the possible metabolic basis for changes in nitrogen losses during growth and development is discussed.
4. Mean values for whole-body protein synthesis and breakdown were 26·3 ± 7·0 and 23·8 ± 7·4 g of protein day−1 kg−1 respectively. Dietary nitrogen intake accounted for 6–18% of the nitrogen flux through the metabolic pool; urea excretion accounted for 2% of the nitrogen flux.
5. The net protein gain, estimated from nitrogen-balance data, accounted for 9·6% of total daily protein synthesis.
6. These results are discussed in relation to published estimates of whole-body protein synthesis and breakdown at various ages. Their possible significance in the assessment of a ‘maintenance’ requirement for protein and amino acids during the period of rapid growth and development is also considered.
Prostaglandin Activity in Sustained Inflammation of Human Skin before and after Aspirin
Authors: Plummer N. A. , Hensby C. N. , Black A. Kobza , Greaves M. W. 
Published: August 2015

1. Pharmacologically active mediators of inflammation were obtained from suction bullae raised on normal and inflamed human abdominal skin. These contained a clear inflammatory exudate, which was analysed for known mediators of inflammation.
2. The exudates were examined for smooth muscle-contracting activity by a superfusion cascade bioassay, for prostaglandin F2α by radioimmunoassay and by Lipidex 5000 gel-partition chromatography for other prostaglandins and related compounds.
3. Tetrahydrofurfuryl nicotinate (Trafuril) was applied topically before and after systemic administration of aspirin. Trafuril alone caused a sustained inflammatory response within minutes of application, which was reduced by prior administration of aspirin (a known prostaglandin synthetase inhibitor).
4. Exudate from inflamed skin showed increased prostaglandin activity compared with exudate from contralateral non-inflamed skin. However, aspirin prevented this increase in prostaglandin activity. Analysis by thin-layer and gas—liquid chromatography further suggested that Trafuril-induced inflammation was mediated by certain prostaglandins and related compounds.
5. No evidence was obtained to suggest any change in histamine or bradykinin after Trafuril. We suggest that the response caused by Trafuril is mediated by increased synthesis of prostaglandins. Aspirin, by blocking prostaglandin synthesis, prevents or reduces the erythema.
Effect of Warfarin on the Metabolism of Phylloquinone (Vitamin K1): Dose—Response Relationships in Man
Authors: Shearer M. J. , McBurney A. , Breckenridge A. M. , Barkhan P. 
Published: August 2015

1. The dose—response relationship between the oral anticoagulant, warfarin, and its effect on the metabolism of phylloquinone (vitamin K1) has been examined in normal male volunteer subjects.
2. In each study the subject received a single, oral dose of warfarin and, 2 h later, an intravenous injection of [1′,2′-3H2]phylloquinone. Changes in the metabolism of phylloquinone were assessed by the fractionation and chromatographic separation of labelled phylloquinone and its metabolites in plasma and urine samples.
3. Increasing doses of warfarin did not affect the rate of disappearance of injected phylloquinone from the plasma but caused the accumulation of increasing amounts of the metabolite, phylloquinone epoxide.
4. Increasing doses of warfarin were found to decrease the proportion of labelled conjugates excreted in the urine as glucuronides and to block progressively the excretion of the normal aglycones of phylloquinone. At the same time there was a progressive increase in the excretion of at least three abnormal aglycones of phylloquinone.
5. The doses or plasma concentrations of warfarin were related to the increase in phylloquinone epoxide in the plasma and to the decrease in the proportion of normal aglycones of phylloquinone in urine by typical log dose—response curves, which were linear over the therapeutic range.
6. The nature of the metabolites detected suggested that the dose—response curves reflected the progressive inhibition by warfarin of the enzyme, phylloquinone epoxide reductase.
7. The results are consistent with the hypothesis that the pharmacological action of oral anticoagulants is closely linked to their ability to inhibit the cyclic interconversion of vitamin K and vitamin K epoxide.
Renal Handling of Dibasic Amino Acids and Cystine in Cystinuria
Authors: Kato Tomoaki 
Published: August 2015

1. The effect of intravenous infusion of l-lysine and l-arginine on the tubular reabsorption of dibasic amino acids and cystine was studied in normal individuals and in homozygous and heterozygous subjects with cystinuria.
2. The control subjects reabsorbed almost all filtered lysine and arginine until the filtered load was elevated about fourfold. With further increased loads the tubular reabsorption began to fall and tended to approach a maximum reabsorption rate. By contrast, the homozygous subjects could not reabsorb the elevated amino acid beyond the endogenous capacity until the filtered load was increased seven- to ten-fold. When the filtered load was further increased, tubular reabsorption proceeded at the normal rate in the cystinuric patients.
3. These findings may be explained by a low-capacity transport system, which acts at low substrate concentrations, being defective in the cystinuric subjects, while a high-capacity transport system, which predominates at high substrate concentrations, remains intact.
4. Lysine and arginine infusion depressed the percentage tubular reabsorption of other dibasic amino acids and cystine both in the control and the cystinuric subjects. In the control subjects the amino acid infusion caused a gradual linear fall in the fractional reabsorption of the dibasic amino acids and cystine, whereas the depressed reabsorption of the dibasic amino acids in the cystinuric patients returned to that observed under the endogenous condition when the filtered load was high. The amino acid load caused only a gradual decrease in cystine reabsorption in the cystinuric patients.
5. In the heterozygous subjects the slope of the titration curves and the depression of the tubular reabsorption were intermediate between those of the control and homozygous subjects.
The Variable-Pressure Neck-Chamber Method for Studying the Carotid Baroreflex in Man
Authors: Ludbrook J. , Mancia G. , Ferrari A. , Zanchetti A. 
Published: August 2015

1. The variable-pressure neck-chamber method was analysed in ten healthy volunteer subjects to determine its suitability for the study of the carotid baroreceptor reflex in man.
2. Positive and negative pressures applied to the neck (range ± 60 mmHg) were always transmitted linearly to a tissue catheter outside the carotid sinus, but only 86% of positive pressure, and 64% of negative pressure. Tissue pressures were confirmed by simultaneous measurement in the internal jugular vein adjacent to the carotid sinus.
3. Positive and negative pressure changes within the above range did not alter Po2 of internal jugular venous blood, suggesting that cerebral blood flow was unaltered.
4. Positive pressure changes induced reflex pressor responses of similar magnitude at arterial Po2 12·8 and 70·1 kPa (96 and 527 mmHg), suggesting that the carotid chemoreceptors were not involved.
5. It is concluded that the variable-pressure neck chamber is a valid method for selectively studying the carotid baroreceptor reflex in man. However, transmission of external pneumatic pressure to the carotid sinus is imperfect and greater for positive than for negative pressure. This must be recognized to avoid underestimation of gain and distortion of shape of the reflex.
Control of Renal Tubular Phosphate Reabsorption by Parathyroid Hormone in Man
Authors: Walker D. A. , Davies S. Joyce , Siddle K. , Woodhead J. S. 
Published: August 2015

1. The maximum tubular reabsorption capacity for phosphate relative to glomerular filtration rate (Tm,P/GFR) was found to range from 0·8 to 1·5 mmol/l in 32 normal fasting subjects. In 14 patients with primary hyperparathyroidism and five patients with hyperparathyroidism secondary to vitamin D deficiency or malabsorption values ranged from 0·2 to 0·8 mmol/l.
2. Plasma parathyroid hormone concentrations measured by an immunoradiometric technique ranged from <0·15 to 0·9 ng/ml in the normal subjects and from 0·5 to 10 ng/ml in the patients with hyperparathyroidism. There was no correlation, however, between plasma parathyroid hormone and Tm,P/GFR in either normal or abnormal groups.
3. Plasma parathyroid hormone was lower in 11 out of 13 patients with primary hyperparathyroidism 3 or 4 weeks after tumour removal than immediately before the operation. In all cases there was a rise in Tm,P/GFR, though not all values were normalized.
4. Changes in plasma parathyroid hormone, Tm,P/GFR and plasma and urinary cyclic AMP concentrations were measured during infusion of bovine parathyroid hormone into normal fasting subjects. Phosphate reabsorption fell markedly in response to low doses of parathyroid hormone (0·5 i.u. h−1 kg−1), higher doses (4 i.u. h−1 kg−1) producing little additional change in Tm,P/GFR despite large changes in cyclic AMP excretion. At the highest doses used (8 i.u. h−1 kg−1) apparent saturation of the renal adenylate cyclase occurred. During an infusion of hormone, 0·25 i.u. h−1 kg−1 over 3 h, a fall in Tm,P/GFR was recorded at concentrations of immunoreactive parathyroid hormone within the normal range for endogeneous hormone. At such concentrations it was not possible to detect significant changes in either plasma or urine cyclic AMP.
5. It is concluded that parathyroid hormone is an important regulator of renal phosphate handling under normal physiological conditions. Such a regulatory process has been implicated in the control of vitamin D metabolism.
The Effect of α-Adrenoreceptor Stimulation on the Airways of Normal and Asthmatic Man
Authors: Snashall P. D. , Boother Frances A. , Sterling G. M. 
Published: August 2015

1. The bronchial response to α-adrenoreceptor stimulation has been investigated in normal and asthmatic subjects with a specific α-receptor agonist, methoxamine hydrochloride, after atropine and β-adrenergic blockade.
2. No significant changes in forced expiratory volume in 1 s (FEV1·0) were seen in normal subjects.
3. Methoxamine inhalation caused mild symptomatic wheezing and significant falls in FEV1·0 in asthmatic subjects. No change in FEV1·0 occurred after inhalation of distilled water as control.
4. It therefore appears that methoxamine causes bronchoconstriction in asthmatic subjects through its α-adrenergic-stimulating properties, since we were not able to detect any β-receptor-blocking activity of methoxamine on the airways.
Evidence of Increased Oxalate Absorption in Patients with Calcium-Containing Renal Stones
Authors: Hodgkinson A. 
Published: August 2015

1. The possible roles of the diet and of intestinal absorption in the increased excretion of oxalate by patients with renal calcium stones have been studied.
2. Dietary surveys showed that the mean daily intake of oxalic acid by stone-formers was not significantly different from that of non-stone-formers.
3. The mean urinary excretion of oxalate, expressed as an oxalate/creatinine molar ratio, was significantly reduced by fasting, the change being more marked in the stone-formers than in the normal subjects. Moreover, fasting abolished the difference in mean oxalate/creatinine ratios between stone-formers and control subjects.
4. These results are compatible with the hypothesis that the small increases in urinary oxalate excretion which occur in some idiopathic calcium oxalate stone-formers are due to increased absorption of oxalate from the intestine, which may be due to a reduction in intraluminal calcium concentration.
Lecithin—Cholesterol Acyltransferase and the Lipoprotein Abnormalities of Obstructive Jaundice
Authors: Agorastos J. , Fox C. , Harry D. S. , McIntyre N. 
Published: August 2015

1. We have studied the plasma lipoprotein abnormalities in obstructive jaundice to test the hypothesis that the abnormalities would correlate with plasma lecithin—cholesterol acyltransferase activity.
2. Very-low-density lipoproteins (VLDL) were normal in composition and had a normal pre-β electrophoretic mobility when lecithin—cholesterol acyltransferase activity was high. When it was low VLDL had abnormal composition and ran in the β position.
3. With high lecithin—cholesterol acyltransferase activity, low-density lipoprotein (LDL) was normal and cholestatic LDL (LP-X) was not found. With low lecithin—cholesterol acyltransferase activity up to three LDL fractions were found: (i) large triglyceride-rich particles, (ii) LP-X and (iii) a triglyceride-rich cholesteryl ester-poor particle of normal dimensions.
4. High-density lipoprotein (HDL) concentrations correlated with lecithin—cholesterol acyltransferase activity and HDL were normal in composition and electron-microscopic appearance when the activity was high. When lecithin—cholesterol acyltransferase activity was low HDL was abnormal in composition and ‘stacked discs’ were seen on electron microscopy as well as normal spherical particles.
5. These results suggest that low lecithin—cholesterol acyltransferase activity may cause at least some of the lipoprotein changes of obstructive jaundice.
Effect of Carbamazepine on Plasma and Urine Arginine-Vasopressin
Authors: Thomas T. H. , Ball S. G. , Wales J. K. , Lee M. R. 
Published: August 2015

1. Five normal subjects were studied before and during treatment with carbamazepine.
2. Plasma sodium, plasma and urine arginine-vasopressin and urine osmolality were measured during a day of water deprivation, before and during drug treatment.
3. During treatment with carbamazepine plasma sodium increased whereas plasma and urine arginine-vasopressin and urine osmolality decreased. Plasma and urine arginine-vasopressin were significantly correlated with urine osmolality. However, carbamazepine did not affect the osmolality of urine produced by the kidney, in response to endogenous arginine-vasopressin.
4. Plasma and urine arginine-vasopressin were significantly correlated with plasma sodium on both control and drug-treatment days, but the relationships of plasma and urine arginine-vasopressin to plasma sodium were different during carbamazepine treatment, as compared with the control period.
5. It is suggested that the threshold of the hypothalamic osmoreceptors for release of arginine-vasopressin is modified by carbamazepine, and that this may be either a direct action or secondary to another action of the drug.
Effect of Antitonin on Blood Pressure in the One-Kidney Hypertensive Rat
Authors: Garcia R. , Boucher R. , Gutkowska J. , Kondo K. , Demassieux S. , Genest J. 
Published: August 2015

1. The tonin concentration of saliva and submaxillary glands was studied in one-clip hypertensive rats with or without the contralateral kidney.
2. Salivary tonin concentration was elevated in one-kidney hypertensive rats, but not in one-kidney normotensive or two-kidney, one-clip hypertensive rats. In contrast, an elevated submaxillary gland tonin concentration was found only in uninephrectomized animals, whether normotensive or hypertensive.
3. A single intravenous administration of rabbit tonin antiserum into one-kidney hypertensive rats restored blood pressure to normal in seven out of ten animals. There was little change in blood pressure in two-kidney, one-clip hypertensive, uninephrectomized or sham-operated rats.
4. These findings suggest a connection between the physiology of the kidney and of the submaxillary gland in the rat, and indicate that tonin may play a significant role in maintaining high blood pressure in one-kidney hypertensive animals.
Determination of Human Leg Blood Flow: A Thermodilution Technique Based on Femoral Venous Bolus Injection
Authors: Jorfeldt L. , Juhlin-Dannfelt A. , Pernow B. , Wassén E. 
Published: August 2015

1. A thermodilution method was developed for the determination of human leg blood flow. The method is based on bolus injection of an indicator distally into the femoral vein, at room temperature, and recording of the dilution curve in the same vessel at the level of the inguinal ligament. The blood flow was computed automatically with two thermistors and an integrator.
2. The leg blood flow determined by this method at rest and during exercise at work loads of 50, 100 and 150 W in six healthy subjects was found to agree closely with measurements by an intraarterial indicator-dilution technique. A linear relationship was found between leg blood flow and work. The reproducibility of the blood flow determinations, expressed as the coefficient of variation for a single determination, was 12·9 at rest and 5·3 or less during exercise.
3. The method was used in two patients with occlusive arterial disease of the leg. Extremely low leg blood flows were found in these patients when they were forced to interrupt the exercise by severe calf pain.
Effect of Varying Pco2 on Intracellular pH and Lactate Consumption in the Isolated Perfused Rat Liver
Authors: Baron P. G. , Iles R. A. , Cohen R. D. 
Published: August 2015

1. The effects of varying Pco2 on lactate uptake and intracellular pH (pHl) were studied in the isolated rat liver perfused with differing concentrations of lactate.
2. In general, pHl and lactate uptake are inversely related to Pco2, and pHl and lactate uptake are directly related to each other, but the quantitative aspects and significance of these relationships vary with the availability of lactate. A model of hepatic lactate metabolism is proposed which may account for the quantitative variation.
3. The metabolism of lactate within the hepatocyte exerts a destabilizing effect on hepatocyte cell pH, in contrast to the buffering effect seen in predominantly glycolytic tissues.
4. An attempt is made to relate the findings to the disturbances of lactate metabolism in clinical respiratory failure.
Mechanism of the Effect of Varying Pco2 on Gluconeogenesis from Lactate in the Perfused Rat Liver
Authors: Iles R. A. , Baron P. G. , Cohen R. D. 
Published: August 2015

1. The effects of varying Pco2 on glucose output and the intracellular concentrations of lactate, pyruvate, phosphoenolpyruvate, 2-phosphoglycerate and 3-phosphoglycerate were studied in the isolated rat liver perfused with differing concentrations of lactate.
2. When the perfusate lactate concentration is above 1.5 mmol/l respiratory acidosis (simulated by high perfusate Pco2) inhibits gluconeogenesis from lactate, whereas respiratory alkalosis stimulates gluconeogenesis.
3. In general there were significant positive correlations between intracellular pH (pHl) and hepatocyte phosphoenolpyruvate, 2-phosphoglycerate and 3-phosphoglycerate concentrations, and negative correlations between pHl and lactate and pyruvate concentrations; there were usually significant correlations in the opposite sense between these metabolites and log Pco2.
4. The results suggest that CO2 exerts an inhibitory effect on gluconeogenesis at a step between pyruvate and phosphoenolpyruvate; however, this is not the only effect of CO2 on the gluconeogenic sequence. CO2 probably acts by changing pHl, but direct effects of CO2 and HCO−3 cannot be excluded.
5. Except at low lactate concentrations, non-ionic diffusion probably does not play a major role in the entry of lactate into the hepatocyte.