bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sodium Distribution in Mesenteric Arterial Wall of Rats with Hypertension Induced by Drinking Saline
Authors: Madden Jane A. , Smith G. A. , Llaurado J. G. 
Published: August 2015

1. Hypertension was induced in rats by substituting 2% (w/v) sodium chloride solution for drinking water. Sodium distribution in isolated mesenteric arterial wall was studied with the aid of 22Na, which was continuously washed out. Data were analysed by digital computer simulation without recourse to ancillary chemical measurements of extracellular space.
2. A three-compartment model consisting of (i) extracellular, (ii) intracellular and (iii) subcellular space was found to represent adequately the kinetics of 22Na. Transport rate constants were chosen as primary parameters describing intercompartmental sodium exchanges; the ratio of extra- to intra-cellular sodium compartments was calculated.
3. Results show the following significant changes in mesenteric arterial wall of salt-loaded hypertensive rats: (i) slowed sodium turnover; (ii) a decrease of the transport rate constant, which is presumed to reflect sodium movements from the intra- to the extra-cellular compartment; (iii) an increase of the transport rate constant, presumed to reflect sodium movements from the extra- to the intra-cellular compartment; (iv) a diminution of the extra- to intra-cellular compartment ratio for sodium.
4. The results suggest net movement of sodium into the cells; this change may be relevant to smooth muscle contraction and hence to the pathogenesis of blood pressure elevation in this model.
Kinetics of Uptake of An Amino Acid and a Dipeptide into Hamster Jejunum and Ileum: The Effect of Semistarvation and Starvation
Authors: Schedl H. P. , Burston D. , Taylor Elizabeth , Matthews D. M. 
Published: August 2015

1. This paper reports an investigation of the effects of semistarvation and starvation on the kinetics of uptake of an amino acid, l-leucine, and a hydrolysis-resistant dipeptide, Gly-Sar, by rings of everted hamster jejunum and ileum in vitro. The concentration range used was 0·1–100 mmol/l. Total uptake, non-mediated uptake and Kt and Vmax. for mediated influx were estimated.
2. At many concentrations, both semistarvation and starvation caused a decrease in uptake of the peptide and the amino acid. Uptake of the peptide was more severely depressed than that of the amino acid. In control animals, the jejunum was the site of maximal uptake of Gly-Sar, and the ileum the site of maximal uptake of leucine. In semistarved and starved animals, the ileum became the site of maximal uptake of Gly-Sar, as it was for leucine. The effects of semistarvation and starvation on uptake were similar whether this was expressed per unit wt. or per unit length, though they were accentuated when expressed per unit length, since the intestine lost weight per unit length.
3. The main effect of semistarvation and starvation on the kinetics of mediated influx of the amino acid and the peptide was to reduce Vmax. in both jejunum and ileum. This effect was compatible with a reduction in the number of mediated transport sites for both the amino acid and the peptide. The observation that mediated influx of the peptide was more severely affected than that of the amino acid supports the hypothesis of the independence of the mechanisms for intestinal uptake of peptides and amino acids.
Catabolic Effects of Adrenaline and Angiotensin II in the Perfused Liver of Normal and Genetically Obese (ob/ob) Mice
Authors: Ma G. Y. , Gove C. D. , Cawthorne M. A. , Hems D. A. 
Published: August 2015

1. Rapid effects of hormones on the metabolism of glycogen and fatty acids were studied in the perfused liver of normal and genetically obese (ob/ob) mice.
2. In livers from normal and obese mice adrenaline and angiotensin II stimulated glycogenolysis.
3. These hormones inhibited the synthesis de novo of long-chain fatty acids in livers from normal mice, but not in livers from obese mice.
4. The proportion of acetyl-CoA carboxylase in the active form was decreased by adrenaline but not by angiotensin II in livers from obese mice.
5. The potency of hormone effects on liver suggests that they could occur in the intact animal.
6. The results add to the evidence that hepatic fatty acid synthesis in genetically obese (ob/ob) mice is irreversibly resistant to inhibition by a range of hormones. Such resistance could be of primary significance in the pathogenesis of the obesity.
Histamine, Basophils and Eosinophils in Severe Asthma
Authors: Charles T. J. , Williams S. J. , Seaton A. , Bruce Christine , Taylor W. H. 
Published: August 2015

1. Arterial and venous whole blood and plasma histamine concentrations and eosinophil and basophil counts were determined in five patients with acute severe asthma who had not previously received steroid therapy, in five who had been maintained on steroid therapy and in a control group of nine patients with acute non-respiratory illnesses.
2. No significant arteriovenous differences were observed for any of these measurements in any of the groups of patients. Significant net loss of arterial histamine does not therefore occur peripherally in acute asthma.
3. When compared with the values for the controls, statistically significant increases were observed, in the group not receiving steroids, for arterial and venous whole blood histamine concentrations, eosinophil counts and basophil counts, and, in those receiving steroids, for the venous basophil counts.
4. When compared with the venous plasma histamine concentration of normal subjects, that of the asthmatic subjects not receiving steroids was significantly raised.
5. The venous plasma histamine concentration of the control group was also significantly higher than that of normal subjects, but less so than in the asthmatic subjects, suggesting that acute illness per se produces an increased plasma histamine concentration.
6. Both groups of asthmatic patients were treated similarly with hydrocortisone and bronchodilators. There was a striking fall in whole blood histamine concentration and in eosinophil and basophil counts, but plasma histamine fell more slowly, especially in those who had not previously received steroids.
7. The mean histamine content of the basophil cell is 0·01 pmol and significant differences in this value did not occur within the various groups or as a result of treatment. The approximate number of molecules of histamine per basophil cell is 6·0 × 109.
Studies on Porphyrin Biosynthesis and the Enzymes Involved in Bovine Congenital Erythropoietic Porphyria
Authors: Del Batlle Alcira M. , De Xifra Eva A. Wider , Stella Ana Maria , Bustos Norma , With T. K. 
Published: August 2015

1. Porphyrin biosynthesis and the enzymes succinyl-CoA synthetase (EC 6.2.1.5), δ-aminolaevulinate synthase (EC 2.3.1.37), δ-aminolaevulinate dehydratase (EC 4.2.1.24) and porphobilinogenase enzyme complex at 37°C and 45°C were studied in blood, bone marrow, spleen, liver and kidney of normal bulls and a bull with congenital erythropoietic porphyria (CEP).
2. Biosynthesis by erythrocytes and spleen was low and slightly lower in CEP than in the normal animals. In liver and kidney biosynthesis was somewhat higher and still lower in CEP than in normal animals. In bone marrow it was high and considerably higher in CEP than in normal animals. In all tissues biosynthesis was higher from porphobilinogen than from δ-aminolaevulinic acid.
3. The porphyrin biosynthesis pattern was 40% uroporphyrin, 15% heptacarboxylic porphyrin, 25% coproporphyrin and 20% suburoporphyrin in the normal animals, but in CEP it was 50% uroporphyrin I, 20–30% uroporphyrin III, 10–12% heptacarboxylic porphyrin and 10–20% suburoporphyrin.
4. In CEP gall-bladder bile contained 100 μmol of coproporphyrin/l and the fresh bladder urine 9 μmol/l, which on standing increased to 21 μmol/l, pointing to excretion of most porphyrin as porphyrinogen in the urine. The blood plasma contained only traces of porphyrin.
5. Enzyme determinations showed threefold increased succinyl-CoA synthase in CEP bone marrow as compared with normal animals, many-fold increase of aminolaevulinate synthase, normal aminolaevulinate dehydratase, sevenfold increase of porphobilinogenase activity on incubation at 45°C and threefold increase at 37°C. In blood, aminolaevulinate synthase and aminolaevulinate dehydratase were increased in CEP, whereas porphobilinogenase at 45 °C was reduced. In liver, aminolaevulinate synthase was normal and porphobilinogenase decreased.
6. Our results show that in this animal with CEP there was an increased porphobilinogen deaminase and a significant enhancement of aminolaevulinate synthase concomitant with a diminished activity of uroporphyrinogen III cosynthase.
Absence of Adrenergic Mediation of Agonist Response to [Sar1,Ala8]Angiotensin II in Conscious Normotensive and Hypertensive Dogs
Authors: Zimmerman B. G. 
Published: August 2015

1. In the conscious normotensive and two-kidney Goldblatt hypertensive dog a transient agonist response to the intravenous infusion of saralasin (1 μg min−1 kg−1) was manifested by a small increase in blood pressure (6–12 mmHg) and 28–30% increase in renal vascular resistance.
2. These increases in blood pressure and renal vascular resistance were unaffected by administration of either phentolamine or guanethidine.
3. The agonist response in the conscious dog is most likely accounted for by a direct action of saralasin on vascular angiotensin receptors.
Superficial or Membrane Digestion of Peptides in Dinitrophenol-Inhibited Rat Small Intestine
Authors: Gardner M. L. G. 
Published: August 2015

1. Hydrolysis of peptides has been measured in isolated rat small intestine perfused with a pancreatic digest of lactalbumin in the presence of 2,4-dinitrophenol.
2. Although transport of water and amino acids was severely inhibited by 2,4-dinitrophenol, peptide hydrolysis to free amino acids was apparently unimpaired.
3. Only a small fraction of the hydrolysis observed could be accounted for by leakage of enzymes into the lumen.
4. The results show that the brush-border enzymes proximal to the transport mechanism(s) can be an important site of hydrolysis of peptides to amino acids under conditions where the transport of unhydrolysed peptides is inhibited. The results are consistent with the concept of membrane (contact) digestion, although the significance of intracellular hydrolysis and of transmural transport of intact peptides is also discussed.
Sodium Excretion in Man, and Adaptation to a Low-Sodium Diet: Effect of Intravenous Sodium Chloride
Authors: Gordon D. , Peart W. S. 
Published: August 2015

1. The aim of this study was to test whether a postulated gastrointestinal or portal monitor of sodium intake plays any part in adjusting renal sodium excretion when dietary sodium is reduced.
2. Normal male subjects were given 50 mmol of sodium chloride intravenously three times daily for 3 days to replace or to supplement a constant oral intake of sodium chloride.
3. When oral sodium chloride was replaced with intravenous sodium chloride, renal sodium excretion remained constant.
4. When oral sodium chloride was kept constant, sodium administered as intravenous sodium chloride was promptly excreted in three out of four subjects. There was a delay in the increase in sodium excretion in the fourth subject.
5. Infusions containing 50 mmol of sodium chloride in 50 ml given intravenously over 22 min produced a rise in plasma sodium concentration and a fall in concentration of total plasma solids.
6. These results provide no evidence for a gastrointestinal or portal monitor of sodium intake, but do not disprove the existence of such a monitor.
Biochemical Discrimination of Hurler and Scheie Syndromes
Authors: Hopwood J. J. , Muller Vivienne 
Published: August 2015

1. Homogenates of cultured skin fibroblasts derived from patients with α-l-iduronidase-deficiency disorders (Hurler and Scheie syndromes) were capable of hydrolysing iduronosyl anhydro-[l-3H]mannitol 6-sulphate although at considerably reduced rates compared with normal controls.
2. The Vmax. values of α-l-iduronidase from patients with Hurler or Scheie syndromes and from normal controls were 11, 12 and 833 pmol min−1 mg−1 of protein respectively; the corresponding apparent Km values were 656, 50 and 53 μmol/l respectively. The α-l-iduronidases from normal and Scheie fibroblast homogenates were shown to exhibit pH optima at 3·6 and 4·1 and were competitively inhibited by both chloride and sulphate ions: Hurler α-l-iduronidase activity exhibited one pH optimum at 3·8 and was also inhibited by chloride and to a lesser extent by sulphate ions.
3. The thermal stability of Hurler, Scheie and normal α-l-iduronidase activities at 55°C gave half-lives of approximately 1·0, 2·5 and 1·0 h respectively.
4. These biochemical findings clearly demonstrate enzyme differences for these two clinically distinct phenotypes and provide biochemical evidence that the Hurler and Scheie syndromes result from different allelic mutations.
Muscle Relaxation Rate, Fibre-Type Composition and Energy Turnover in Hyper- and Hypo-Thyroid Patients
Authors: Wiles C. M. , Young A. , Jones D. A. , Edwards R. H. T. 
Published: August 2015

1. Quadriceps strength, relaxation rate, fibre-type composition and energy-turnover rate during a submaximal contraction have been measured in hypo- and hyper-thyroid patients and compared with findings in normal subjects.
2. Six out of eight hypothyroid patients had normal strength whereas four out of five hyperthyroid patients were weak.
3. Relaxation rate was decreased in all the hypothyroid patients but increased in only three out of five hyperthyroid patients.
4. In hypothyroidism there was a marked reduction in the percentage contributed by type II fibres to muscle cross-section, partly due to type II atrophy but also due to a decrease in the relative frequency of type II fibres. In hyperthyroidism both fibre types tended to atrophy.
5. The rate of ATP turnover during submaximal contraction held to fatigue was reduced in hypothyroidism. This was probably due to decreased ATP utilization rather than an impaired supply of energy-supplying substrates. In hyperthyroidism the rate of ATP turnover was increased.
6. Altered relaxation rate and ATP-turnover rate may be explained on the basis of changes in myosin ATPase activity with thyroid status. Changes in muscle-fibre-type composition, as determined histochemically, could not per se account for the functional abnormalities.
A Method for Standardizing Airway Resistance for Variations in Lung Volume
Authors: Higenbottam T. , Clark T. J. H. 
Published: August 2015

1. The inverse relationship between airway resistance and lung volume contributes to variation in measurement of resistance, as it is difficult to control precisely the lung volume at which resistance is determined each time. A correction for variation in lung volume was applied to measurement of airway resistance by using analysis of covariance with lung volume as a covariate. This method provides an assessment in each subject of degree of association between airway resistance and lung volume and uses the individual's unique slope, relating resistance to volume in order to correct resistance to a single lung volume. The corrected measurement of airway resistance was compared with conventional volume-standardized variables such as specific airway resistance, specific airway conductance and the logarithmic transformation of the latter.
2. Eight normal male subjects had airway resistance and lung volume measured in a body plethysmograph, a mean of seven measurements being made. They then inhaled histamine.
3. Airway resistance showed only a limited association with lung volume and the slopes relating the two measurements varied between subjects. Covariance-corrected airway resistance appeared more sensitive than other methods of volume standardization in detecting bronchoconstriction.
4. Analysis of covariance adequately corrects airway resistance for variations in lung volume but further studies are required to validate its precision and sensitivity.
Plasma 25-Hydroxy-Vitamin D in Normal Subjects and Patients with Terminal Renal Failure, on Maintenance Haemodialysis and after Transplantation
Authors: Eastwood J. B. , Daly A. , Carter G. D. , Alaghband-Zadeh J. , De Wardener H. E. 
Published: August 2015

1. Plasma 25-hydroxy-vitamin D concentration was measured in 40 normal subjects, 19 patients with terminal renal failure, 137 patients who had been on dialysis up to 11 years and in 17 renal transplant patients.
2. The mean plasma concentration of 25-hydroxy-vitamin D was below normal in patients with terminal renal failure and in patients who had been on maintenance haemodialysis for less than 1 year. The mean concentration in patients who had been on dialysis for more than 1 year and in renal transplant patients was normal.
3. The seasonal variation of plasma 25-hydroxy-vitamin D concentration found in the 58 patients on maintenance haemodialysis for more than 2 years is similar to that reported in normal subjects.
Interaction of Amino Acids with Glycyl-l-leucine Hydrolysis and Transport in Monkey Small Intestine
Authors: Ganapathy V. , Radhakrishnan A. N. 
Published: August 2015

1. There are two saturable transport processes in the monkey small intestine for glycyl-l-leucine, one with Kmax 1 μmol min−1 g−1 wet weight of tissue and an affinity constant (kt) of 5 mmol/l, and the other with Vmax. 3·9 μmol min−1 g−1 wet weight of tissue and kt 33 mmol/l.
2. Glycyl-l-leucine uptake is inhibited by a wide variety of amino acids, although to a variable extent. The inhibition was shown to be competitive with leucine used as the representative amino acid. Phenylalanine, methionine, alanine and leucine are the most potent in their inhibitory action.
3. The effect of various amino acids on the hydrolysis of glycyl-l-leucine by particulate and cytosol fractions of monkey small intestine was studied. All the amino acids, except glycine, proline, alanine and glutamic acid, inhibit both the particulate and cytosol glycyl-l-leucine hydrolase activities. In general, the cytosol enzyme is more susceptible to amino acid inhibition than the particulate enzyme.
4. There is no correlation between the effects of amino acids on glycyl-l-leucine uptake and hydrolysis of glycyl-l-leucine by either particulate or cytosol fraction.
Relationship between Exchangeable Sodium and Blood Pressure in Different Forms of Hypertension in Man
Authors: Davies D. L. , McElroy K. , Atkinson A. B. , Brown J. J. , Cumming A. M. M. , Fraser R. , Leckie B. J. , Lever A. F. , MacKay A. , Morton J. J. , Robertson J. I. S. 
Published: August 2015

1. Arterial pressure and exchangeable sodium (NaE) were measured in patients with Conn's syndrome, essential hypertension, renal artery stenosis and chronic renal failure. Comparison was made with a control group. Urine sodium excretion was measured separately from the two kidneys in patients with renal artery stenosis.
2. Compared with control, mean NaE was significantly increased in Conn's syndrome, and was normal in essential hypertension, renal artery stenosis and chronic renal failure.
3. The correlation of arterial pressure with NaE was positive and significant in Conn's syndrome, essential hypertension and chronic renal failure.
4. In contrast the correlation was significantly negative in unilateral renal artery stenosis. Patients with lowest NaE had hyponatraemia, hypokalaemia and secondary hyperaldosteronism.
5. Urinary sodium excretion from the unaffected kidney in unilateral renal artery stenosis correlated positively with arterial pressure, possibly reflecting the phenomenon of pressure-natriuresis. Patients subsequently responding least well to surgery excreted least sodium from the untouched kidney for a given arterial pressure.
6. The findings suggest important roles for arterial pressure in the regulation of sodium balance (predominant in renal artery stenosis), and for sodium balance in the regulation of arterial pressure (predominant in Conn's syndrome). The observations in essential hypertension are compatible either with an exact balance between these mechanisms or with the existence of some other mechanism raising blood pressure.
Baroreflex Control of Blood Pressure and Plasma Noradrenaline during Exericse in Essential Hypertension
Authors: Sleight P. , Floras J. S. , Hassan M. O. , Jones J. V. , Osikowska B. A. , Sever P. , Turner K. L. 
Published: August 2015

1. Twelve subjects (mean age 46·3 ± 12·5 years) with mild to moderate hypertension were studied before, during and after bicycle ergometer exercise.
2. Baroreflex sensitivity was determined by the Oxford phenylephrine method; sensitivity at rest was inversely related to intra-arterial pressure and age. Age and resting arterial pressure were not related.
3. Exercise for 5 min at 50 W and 5 min at 75 W raised the mean arterial pressure from 116·4 ± 18·0 to 150·0 ± 25·4 mmHg, the heart rate from 73·2 to 126·7 beats/min and the plasma noradrenaline from 541 ± 142·7 to 1309·8 ± 543·5 pg/ml (P &lt; 0·001).
4. The increase in noradrenaline during exercise and the maximum mean pressure achieved were inversely related to resting baroreflex sensitivity (r = −0·68 and −0·77 respectively). Resting values of noradrenaline were not related to baroreflex sensitivity, age, or resting blood pressure.
5. It is possible that the rise in both plasma noradrenaline and arterial blood pressure produced by exercise is controlled by the baroreceptor reflexes; these are less effective in hypertensive subjects and thus the increases in noradrenaline and arterial pressure during exercise are greater in subjects with raised blood pressure.
Uptake and Efflux of Noradrenaline from Platelets; a Model System for Neurogenic Mechanisms in Essential Hypertension
Authors: Mattiasson I. , Mattiasson B. , Hood B. 
Published: August 2015

1. The rate (k) of initial efflux of noradrenaline from platelets was determined in 63 individuals. A highly significant correlation was found between diastolic blood pressure and efflux rate.
2. When platelets are incubated in buffers with various Na+ concentrations in the range 110–170 mmol/l a higher Na+ concentration will give a faster efflux of noradrenaline for each concentration tested.
3. The value for k was determined in 41 normotensive first-degree relatives of hypertensive individuals and 21 persons with no family history of hypertension. Efflux rate of noradrenaline was significantly higher in the relatives and within this group was a subgroup with very high k values.
Inhibition of Urinary Kallikrein Excretion by Semi-Purified Renin in the Rat
Authors: Croxatto H. R. , Silva G. , Boric M. 
Published: August 2015

1. Rat kidney extracts obtained at successive stages of a purification procedure, which allows the separation of renin and kallikrein, were used in order to investigate their effect upon urinary excretion of kallikrein, sodium, potassium and water in hyperhydrated rats.
2. Only the purified fraction containing renin reduced kallikrein excretion. The decrease of kallikrein coincided with a considerable increase in sodium, potassium and water excretion.
3. The natriuretic effect of renin extract did not depend on the presence of kallikrein. The injection of a mixture of renin and kallikrein attenuated the effect of renin alone, indicating that both enzymes exert antagonistic actions on the excretion of electrolytes and water by the kidneys.
4. A purified fraction of kidney extract containing no kallikrein and only traces of renin activity, had a stimulatory effect on kallikrein, water and elctrolyte excretion.