bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biliary Excretion of Dibromosulphthalein in the Freely Moving Unanaesthetized Rat: Circadian Variation and Effects of Deprivation of Food and Pentobarbital Anaesthesia
Authors: Vonk R. J. , Scholtens E. , Strubbe J. H. 
Published: August 2015

1. In unanaesthetized, freely moving rats, which displayed a circadian rhythm in bile flow, hepatic transport of dibromosulphthalein was investigated at midnight when bile flow was high and at noon when bile flow was lower. The influence of pentobarbital anaesthesia and starvation on hepatic transport of dibromosulphthalein was also studied. The influence of bile salts on the hepatic transport process was investigated by interruption of the enterohepatic circulation.
2. Maximal biliary transport of dibromosulphthalein was subject to circadian variations: the biliary transport maximum at night was 25% higher than at noon, although maximal biliary concentration was not significantly altered. The distribution volume was increased by 21% during the night, but the primary hepatic clearance constant was not changed.
3. Pentobarbital anaesthesia decreased the maximal biliary concentration and the maximal biliary excretion rate of dibromosulphthalein, but the primary hepatic clearance constant was not changed.
4. Starvation for 48 h changed the primary hepatic clearance constant as well as the biliary excretion of dibromosulphthalein.
5. Interruption of the enterohepatic circulation of bile did not change the primary hepatic clearance constant of dibromosulphthalein, but decreased biliary excretion of the drug.
6. This study clearly indicates that time of the day, feeding conditions, the use of anaesthetics and interruption of the enterohepatic circulation of bile are important determinants in biliary excretion of cholephilic dyes.
Analytical Subcellular Fractionation Studies on Different Cell Types Isolated from Normal Rat Liver
Authors: Selden Clare , Wootton A. M. , Moss D. W. , Peters T. J. 
Published: August 2015

1. Parenchymal, Kupffer and biliary tract cells were isolated from normal rat liver by perfusion with collagenase solution.
2. The specific activities (munits of enzyme activity/mg of protein) of marker enzymes for the principal subcellular organelles were determined in the isolated cell homogenates and compared with whole liver homogenates.
3. The cells were disrupted and the extracts subjected to analytical subcellular fractionation by sucrose-density-gradient centrifugation. Lysosomal integrity was determined by assaying latent β-N-acetylglucosaminidase in the extracts.
4. Similar subcellular distributions were found for lysosomal, endoplasmic reticulum and plasma membrane marker enzymes in the whole liver and in parenchymal and biliary tract cells. In Kupffer cells, the proportion of these enzymes in the cytosol was significantly increased compared with the other fractions. In addition the equilibrium densities of the various organelles in these cells were lower than those from parenchymal cells.
Comparison of Cardiac Output Determined by a Carbon Dioxide-Rebreathing and Direct Fick Method at Rest and during Exercise
Authors: Reybrouck T. , Amery A. , Billiet L. , Fagard R. , Stijns H. 
Published: August 2015

1. To study the validity of a CO2-rebreathing method at rest and during graded exercise, cardiac output was measured simultaneously on 59 occasions in 16 subjects with normal pulmonary function with the CO2-rebreathing method and the direct Fick method for oxygen. The correlation coefficient between the results of both methods was significantly higher during exercise than at rest.
2. No systematic difference was shown between (a-v̄)CO2 content difference determined on whole blood and end-tidal gas, which justified the exclusion of a correction factor for blood to alveolar gas Pco2 gradients.
3. In the calculation of cardiac output by the direct Fick method for CO2 and by CO2 rebreathing, a standard CO2 dissociation curve was preferred to a synthetic CO2 dissociation curve, constructed by allowance for changes in haemoglobin concentration, pH and oxygen saturation. The latter curve tended to increase values for cardiac output and induced a large dispersion around the line of identity, when compared with simultaneous cardiac output estimates by the direct Fick method for oxygen.
The Nature of Hepatic Cytochrome P-450 Induced in Hexachlorobenzene-Fed Rats
Authors: Blekkenhorst G. H. , Eales L. , Pimstone N. R. 
Published: August 2015

1. The effect of feeding with a diet containing 0.2% (w/w) hexachlorobenzene on hepatic and urinary porphyrins and hepatic cytochrome P-450 was studied at various time intervals in female Wistar rats.
2. Hexachlorobenzene administration for 45 days resulted in the development of porphyria in rats, which biochemically closely resembles symptomatic porphyria in humans, with elevation of urinary uroporphyrin excretion, hepatic uroporphyrin content, and hepatic cytochrome P-450 content, in addition to appearance of porphyrins of the isocoproporphyrin (P1) series in the faeces.
3. Spectral studies of the induced hepatic cytochrome P-450 at 45 days with carbon monoxide and ethyl isocyanide as ligands indicated the presence of a greater admixture of a haemoprotein distinct from cytochrome P-450.
4. Study in vitro of the kinetics of two reactions, namely aminopyrine N-demethylation and 3,4-benzpyrene hydroxylation, catalysed by the hepatic microsomal cytochrome P-450-dependent enzyme system, suggested that hexachlorobenzene induced a form of cytochrome P-450 with different catalytic properties from those of forms induced by either phenobarbital or 3-methylcholanthrene.
The Physical Properties of Human Pulmonary Arteries and Veins
Authors: Banks J. , Booth F. V. McL. , MacKay E. H. , Rajagopalan B. , De J. Lee G. 
Published: August 2015

1. We have studied the extensibility of circumferential strips of main pulmonary artery and large pulmonary veins obtained at post mortem from patients of all ages, dying from conditions other than heart and lung disease.
2. The vessel strips were submitted to increasing loads in a tension balance. The pulmonary arteries were found to be readily extensible. This extensibility became less with increasing age. The pulmonary veins were virtually inextensible at all ages.
3. It is postulated that the large extraparenchymal pulmonary veins have a capacitative role in supplying blood from the lungs to the left atrium. This may be accomplished by their collapsible nature, as they have little capability of distension.
The Retention of Lung Secretions during the Night in Normal Subjects
Authors: Bateman J. R. M. , Pavia D. , Clarke S. W. 
Published: August 2015

1. Mucociliary clearance has been measured over a 6 h period by using the radioaerosol technique in seven normal male subjects lying supine, both during the day when awake, and during the night when asleep.
2. The percentage of radioaerosol cleared during the night, when asleep, was significantly less than during the day when awake (P < 0.02).
3. A comparison of radioaerosol clearance before and after the time of onset of sleep demonstrates that reduced clearance occurred during sleep, indicating that this is probably a sleep-related phenomenon and not merely a result of diurnal variation.
4. This finding has important implications for patients with chronic bronchitis or asthma, in whom early morning cough or wheeze may be a predominant feature.
The Role of Prostaglandins in the Pathogenesis of Hypertension
Authors: Markov C. M. 
Published: August 2015

1. Biosynthesis of PGE2 from [14C]arachidonic acid has been found to be lower and PGF2α higher in the renal medulla of spontaneously hypertensive (SH) rats than in normal Wistar (NW) rats.
2. Biosynthesis of prostacyclin (PGF1α) from [14C]arachidonic acid was decreased in lungs, aorta and heart of SH rats.
3. Metabolism of [3H]PGF1α was decreased in renal cortex and lungs and PGE2 increased in SH rats in comparison with NW rats. Thus the lungs of SH rats let more PGF and less PGE enter the systemic circulation.
4. Emotional stress decreased the metabolism of [3H]PGF1α in lungs of SH and NW rats, the effect being less in SH rats.
The Natural History of Hypertension in Turkeys
Authors: Pagnan A. , Pessina A. C. , Thiene G. , Dal Palù C. 
Published: August 2015

1. Variables involved in the genesis of hypertension in male broad-breasted white turkeys include social environment, obesity and high salt intake.
2. The hypertension is characterized by low plasma renin activity and, with increasing age, normal to high plasma aldosterone.
3. Medionecrosis of the abdominal aorta is a common pathological finding.
4. The absence of atherosclerotic plaques is probably related to the high concentrations of alpha-lipoproteins.
Results of a National Therapeutic Trial Conducted in 10 000 Hypertensive Patients by 2000 General Practitioners
Authors: Jouve A. , Goldet L. , Mathieu M. 
Published: August 2015

1. 10 294 hypertensive patients were treated and followed by 2200 general practitioners under the supervision of 130 cardiologists and nephrologists.
2. The treatment groups, randomly allocated, were designated to use three distinct antihypertensive drugs, administered alone, and combined two-by-two.
3. Some 75% of patients had a supine diastolic blood pressure of less than 95 mmHg after 4 months treatment.
4. A total of 12% of patients had dropped out by 4 months from entry; no clear relationship was established between side effects and drop out.
Muscle–Nerve Sympathetic Activity in Man. Relationship to Blood Pressure in Resting Normo- and Hyper-Tensive Subjects
Authors: Sundlöf G. , Wallin B. G. 
Published: August 2015

1. Simultaneous recordings of multi-unit muscle nerve sympathetic activity and arterial blood pressure were made in 29 subjects, 17 healthy and 12 hypertensive. The neural activity, quantified by counting the number of pulse-synchronous sympathetic bursts in the mean voltage neurogram (burst incidence), was plotted against blood pressure. The effect of spontaneous temporary blood pressure fluctuations was studied by correlating different pressure parameters of individual heart beats to the occurrence of a sympathetic burst.
2. Between subjects there were marked differences in burst incidence but no correlation was found to interindividual differences in blood pressure level.
3. When for each heart beat the occurrence of a burst was correlated to different pressure parameters there was a close negative correlation to diastolic, a low correlation to systolic, and an intermediate negative correlation to mean blood pressure.
4. In a given subject, when comparing heart beats with the same diastolic pressure, the occurrence and the amplitudes of the sympathetic bursts were higher during falling than during rising pressure. This directional dependence of the muscle—nerve sympathetic activity was slightly more pronounced in the hypertensive group, but this was considered secondary to the hypertension.
5. The findings of an intimate correlation with dynamic variations in blood pressure and the absence of correlation to the static blood pressure suggest that the sympathetic outflow to skeletal muscle is of importance for buffering acute blood pressure changes but has little influence on the long-term blood pressure.
Metabolism of p-aminobenzoic Acid in the Perfused Livers of Chronically Uraemic Rats
Authors: Howie M. B. , Bourke E. 
Published: August 2015

1. Chronic renal failure was induced in rats by surgical removal of thirteen-sixteenths of renal tissue.
2. The metabolism of p-amino[14C]benzoic acid was studied in the isolated perfused livers of control and chronically uraemic rats. There was a slower rate of clearance and decreased overall metabolism of the compounds in the uraemic rats.
3. Conjugation of p-amino[14C]benzoic acid with glycine and the formation of p-aminobenzoic acid glucuronide were both significantly decreased in the uraemic rats, but there was a significant increase in acetylation of both p-aminobenzoic acid and its glycine conjugate.
Regulation of Glomerular Capillary Pressure and Filtration Rate in Young Kyoto Hypertensive Rats
Authors: Azar S. , Johnson M. A. , Scheinman J. , Bruno L. , Tobian L. 
Published: August 2015

1. Single nephron pressures, flows and resistances were studied in 17–18 week old genetically hypertensive and normotensive Kyoto rats resembling one another in renal weight, total filtration rate, morphology and number of glomeruli in the kidney.
2. Glomerular capillary pressures were similar in the two groups; however, the hypertensive rats had lower pressures at the end of the efferent arteriole than did the normotensive animals. Nephron filtration rates were similar in both groups. At the same time, the hypertensive rats had higher nephron filtration fractions, and their glomerular blood flow was lower than that of the normotensive rats. These changes in the hypertensive animals were due to their higher afferent and efferent arteriolar resistances. Despite their high blood pressure, the glomerular ultrafiltration forces in hypertensive rats were almost identical with those in normotensive rats.
3. We conclude that the regulation of glomerular capillary pressure and filtration rate in young Kyoto hypertensive rats is due to a balance of afferent—efferent arteriolar tonus. The normal glomerular capillary pressures and low efferent arteriolar pressures of these animals are most likely the functional basis for the lack of structural changes at these sites. These results suggest that the Kyoto animal's renal response to hypertension resembles that of most essential hypertensive patients, both in function and morphology.
Effects of ‘Elemental’ Diets on Absorptive and Enzymic Activities and on 5-Fluorouracil Toxicity in Rat Small Intestine
Authors: Gardner M. L. G. , Heading R. C. 
Published: August 2015

1. Water absorption and cytoplasmic dipeptidase activities were determined in isolated rat small intestine after animals had fed on various ‘elemental’ diets or a standard rat diet and after a single injection of 5-fluorouracil.
2. Vivonex diets were associated with a decrease in dry weight of the small intestine and an increase in glucose and water absorption in vitro.
3. The nature of the dietary nitrogen profoundly affects the activities of intestinal peptidases.
4. Water absorption was severely depressed 3 days after 5-fluorouracil administration: the extent of depression was independent of the diet. Thus, any ameliorative effects of ‘elemental’ diets on 5-fluorouracil toxicity are unlikely to be mediated by direct protection of intestinal absorption.
Plasma and Urine Dopamine in Man Given Sodium Chloride in the Diet
Authors: Oates N. S. , Ball S. G. , Perkins C. M. , Lee M. R. 
Published: August 2015

1. Plasma and urine free dopamine were measured daily for 5 days in six normal subjects maintained on a low sodium diet. The subjects were then given dietary supplements of sodium chloride for 5 days and the measurements repeated.
2. Throughout the experiment the 24 h free dopamine excretion rates for all the subjects were higher than could be accounted for by renal clearance. Dopamine excretion increased significantly in response to the added sodium chloride whereas plasma dopamine remained unchanged. The rise in dopamine excretion preceded that of sodium excretion.
3. It is concluded that free dopamine is formed within the kidney in response to increased dietary sodium and may have a role in the control of sodium excretion.
The Relationship between Concentrations of Glycosylated Haemoglobins and of Serum High-Density-Lipoprotein Cholesterol in Diabetic Patients
Authors: Yudkin J. S. , Boucher B. J. , France M. W. , Welch S. G. , Swindlehurst C. 
Published: August 2015

1. Concentrations of high-density-lipoprotein cholesterol and of glycosylated haemoglobins [HbA1(a+b+c)] were measured in non-fasting blood samples taken from 171 diabetic patients.
2. Mean concentrations of high-density-lipoprotein cholesterol were lower in men, and in patients not requiring insulin.
3. There was no correlation between concentrations of high-density-lipoprotein cholesterol and of HbA1(a+b+c) in the patients as a whole, but a significant positive correlation was found between these values in male diabetics not requiring insulin.
4. Changes in the concentrations of HbA1(a+b+c) were not correlated with changes in concentrations of high-density-lipoprotein cholesterol.
Synthetic Detergents in Bile-Salt-Deficient Steatorrhoea
Authors: King R. F. G. J. , Howdle P. D. , Kelleher J. , Losowsky M. S. 
Published: August 2015

1. Fat malabsorption caused by bile-salt deficiency is not easily corrected by standard therapy. It has been shown in rats with bile-salt deficiency that non-ionic detergents can replace bile salts and improve fat absorption. A careful assessment of the place of synthetic detergents such as Tween in human therapy has not been reported.
2. The effects of Tween were studied in 13 patients with bile-salt-deficient steatorrhoea, eight of whom received Tween 80 and five Tween 20.
3. Tween therapy reduced steatorrhoea in 10/13 patients; a mean decrease in faecal fat of 33% was achieved with best effect seen in patients with severe steatorrhoea.
4. In the five patients given Tween 20, duodenal/jejunal intubation was conducted using meals with or without added Tween. Jejunal bile salt concentrations were low in all subjects and Tween had no effect on bile-salt output.
5. With Tween addition micellar free fatty acids and phospholipids were increased in four out of the five patients (mean increases 100% and 260% respectively). The mean ratio of fatty acid to bile salt increased from 1·26 to 3·53 and of phospholipid to bile salt from 0·09 to 0·21 in the presence of Tween.
6. The results suggest that in steatorrhoea due to bile-salt deficiency Tween causes increased micellization of ingested fat and improvement in fat absorption.
7. Tween and other non-ionic detergents may, therefore, find a place in therapy of bile-salt deficiency.
Prolactin in Primary Aldosteronism
Authors: Düsing R. , Gill J. R. , Bartter F. C. 
Published: August 2015

1. This study was done to examine the possibility that escape from the sodium retention produced by aldosterone may be associated with an inhibition of prolactin secretion. Plasma prolactin concentrations were determined in seven patients with adrenal adenoma and aldosteronism, before and after unilateral adrenalectomy, at a time when they were in balance on a sodium intake of 109 mmol/day.
2. After operation, plasma aldosterone was normal [before operation, 52·7 ± 12·1 (supine), 64·6 ± 9·1 ng/dl (upright); after operation, 6·8 ± 1·5 (supine), 11·1 ± 3·0 ng/dl (upright)], while plasma prolactin remained unchanged [before operation, 19·6 ± 2·8 (supine), 15·5 ± 3·3 ng/ml (upright); after operation, 23·8 ± 2·3 (supine), 11·1 ± 3·0 ng/ml (upright)].
3. Our results do not support a role for prolactin in the renal response to aldosterone in man.
Effect of Acid—Base Changes on the Intracellular Sodium, Potassium and Water Content of Human Leucocytes in Vitro
Authors: Jones R. B. , Johnson Valerie E. , Patrick J. , Hilton P. J. 
Published: August 2015

1. Leucocytes were isolated from blood of healthy volunteer subjects and incubated in media of which the bicarbonate, Pco2 and pH composition were varied.
2. The intracellular sodium, potassium and water content of leucocytes were virtually unaffected by the acid—base composition of the media used.
Absorption of Inorganic Phosphate in the Human Small Intestine
Authors: Walton J. , Gray T. K. 
Published: August 2015

1. Intestinal phosphate absorption in human subjects was studied by the technique of triple lumen intestinal perfusion in vivo.
2. Ileal phosphate absorption increased as the intraluminal phosphate concentration was increased.
3. Ileal rates of phosphate absorption were lower at any given intraluminal phosphate concentration than previously described jejunal rates. Acidification of the ileal lumen did not increase phosphate absorption.
4. Phosphate absorption was shown in the jejunum to be dependent on the intraluminal sodium concentration.
5. Phosphate absorption in the human small intestine consists of at least two components, one directly proportional to water movement and the second apparently independent of water movement.
The Rate of Change of Mouth Occlusion Pressure during Exercise
Authors: Siafakas N. , Morris A. J. R. , Prime F. J. 
Published: August 2015

1. The initial rate of change of pressure at the mouth (dP/dt) during a brief occlusion of the airways at the beginning of inspiration has been estimated in nine healthy subjects at rest, during exercise and during the first 2 min of recovery. Exercise was carried out with progressively increasing loads to the maximum tolerated (progressive exercise) and also for a period of 6 min at a constant load of 60% of the maximum (steady-state exercise).
2. A highly significant linear relationship was found between work loads and dP/dt during progressive exercise in all our subjects.
3. A highly significant linear relationship was found between ventilation and dP/dt in both forms of exercise, but the slope of the regression line was steeper during progressive than during steady-state exercise in six out of nine subjects.
4. The pattern of breathing (VT, f, VT/Tinsp., Tinsp./Ttot.) did not account for the difference in the relationship between dP/dt and ventilation during the two forms of exercise.
5. These results are in agreement with the hypothesis that dP/dt is an index of central inspiratory drive.
Long-Term versus Short-Term Effects of Hydrochlorothiazide on Renal Haemodynamics in Essential Hypertension
Authors: Van Brummelen P. , Woerlee M. , Schalekamp M. A. D. H. 
Published: August 2015

1. Renal blood flow, glomerular filtration rate, renal vascular resistance and filtration fraction were studied in ten patients with essential hypertension, during placebo, and after 1 week, 3, 6 and 9 months of hydrochlorothiazide. Plasma renin concentration and urinary excretion of vanillylmandelic acid were also measured.
2. Mean arterial pressure was lowered significantly during hydrochlorothiazide, the long-term effect being slightly more pronounced than the short-term effect.
3. The decrease in renal blood flow during the first week (P &lt; 0·01) was followed by a progressive rise. After 9 months renal blood flow was above placebo level in eight of the ten patients. After an initial decrease, glomerular filtration rate returned gradually to its original value. Renal vascular resistance and filtration fraction increased during the first week and declined thereafter. After 3, 6 and 9 months renal vascular resistance was significantly lower compared with placebo values.
4. Plasma renin concentration and urinary excretion of vanillylmandelic acid increased significantly during the first week of hydrochlorothiazide. Subsequently, vanillylmandelic acid fell to below pretreatment amounts (P &lt; 0·05), whereas plasma renin concentration remained elevated.
5. Long-term treatment of essential hypertension with hydrochlorothiazide has a favourable effect on abnormal renal haemodynamics. Besides the influence of blood pressure reduction per se, humoral and neural factors may be involved.