bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chloride Depletion and Hypochloraemia as a Cause of Renal Sodium and Water Loss in the Rat
Authors: Khanh B. T. , Luke R. G. 
Published: August 2015

1. To study the effects of chloride depletion, without sodium depletion or change in plasma tonicity, on renal excretion of sodium and water, a single exchange peritoneal dialysis was performed in rats against a solution of glucose (15 g/l) containing either NaCl (150 mmol/l, control) or NaHCO3 (150 mmol/l, experimental); KHCO3 (4 mmol/l) was added to both solutions. All rats were prepared before dialysis by a low NaCl diet for 10 days.
2. Peritoneal dialysis against NaHCO3 consistently produced a negative sodium and water balance compared with dialysis against NaCl. Despite this, subsequent electrolyte balance for 3 days showed that chloride-depleted rats excreted significantly more sodium and water and had a reduced urinary osmolality as compared with control animals. Increased sodium and water loss were unexplained by osmotic or bicarbonate diuresis. Kaliuresis was seen in the chloride-depleted rats but muscle potassium was not significantly depressed.
3. With sodium and water loss and continued renal chloride conservation, plasma chloride rose on the average from 88 mmol/l after dialysis against NaHCO3 to 100 mmol/l (control 104 mmol/l) at 72 h. Concomitant with this increase in plasma [Cl−], on the third day after dialysis, during hydropenia, urinary osmolality and papillary [Na+] were not different from control concentrations.
4. It is postulated that chloride depletion and/or hypochloraemia leads to diminished chloride transport in the loop of Henle and that this causes reduced sodium transport into the medulla, impaired concentrating ability and inappropriate urinary sodium loss.
Importance of Hypertension and Genetic Factors for Atherogenesis in Rats
Authors: Yamori Y. , Horie R. , Handa H. , Nara Y. , Ohtaka M. , Fukase M. 
Published: August 2015

1. A new experimental system has been used to analyse factors involved in the initiation of atherosclerosis in rats.
2. Arterial fat deposition in the cerebral arteries was affected by blood pressure, serum cholesterol concentrations, strain difference and age, of which high blood pressure was the most important.
3. A genetic factor independent of hypertension was shown to be involved in acute arterial fat deposition in spontaneously hypertensive rats.
Bone Blood Flow in the Rat Determined by the Uptake of Radioactive Particles
Authors: Tothill P. , McCormick J. St C. 
Published: August 2015

1. Two different suspensions of radioactive particles, 99Tcm-labelled microspheres and 59Felabelled resin particles, were injected into the rat central circulation in order to study the distribution of blood flow to the skeleton.
2. Measurements of particle uptake showed that the mean proportion of cardiac output flowing to the skeleton was 3·1%, a figure much lower than the value of 27% found by Brookes (1970) in a similar experiment.
3. The blood flow per unit mass to individual bones covered a wide range.
Some Factors Influencing the Damaging Effect of Acute Arterial Hypertension on Cerebral Vessels in Rats
Authors: Johansson B. B. 
Published: August 2015

1. Abrupt increase of arterial blood pressure can give rise to multifocal areas of protein extravasation in the brain due to overstretching of the vessels.
2. The vascular tone of the resistance vessels is of importance for the occurrence of the increased permeability.
3. Vasodilatation aggravates the damaging effect of acute hypertension whereas vasoconstriction induced by hyperventilation reduces the incidence of areas of increased permeability.
4. Ligation of a carotid artery prevents lesions in the ipsilateral hemisphere.
The Mechanism for Small-Bowel Adaptation in Lactating Rats
Authors: Elias Elwyn , Dowling R. H. 
Published: August 2015

1. To study the relative contributions of luminal nutrition, bile and pancreatic secretions and hormonal factors in intestinal adaptation, lactation hyperphagia was chosen as a model for increased luminal nutrition, either alone (intestinal transection control group) or in combination with (i) exclusion of bile and pancreatic secretions from the jejunum (by transposition of the jejunum above the Ampulla of Vater) or (ii) exclusion of bile, pancreatic secretions and exogenous luminal nutrition from the jejunum (proximal Thiry—Vella by-pass group).
2. The results confirm that in lactation there is mucosal hyperplasia with increases in villus height and crypt depth, and in small-bowel wet and defatted dry-tissue weights per unit length of intestine.
3. There are corresponding changes in absorptive function with increased glucose and water absorption per unit length of intestine.
4. These structural and functional adaptive changes are proportionately greater in ileum than in jejunum.
5. The exclusion of exogenous luminal nutrition, bile and pancreatic secretions from the jejunum did not diminish the degree of intestinal mucosal hyperplasia and functional adaptation seen in lactation.
6. Diversion to the ileum of greater than normal amounts of bile, pancreatic secretions and luminal nutrition did not further increase the degree of mucosal hyperplasia and enhanced absorption seen in the lactating intestinal transection control group.
7. Unlike other models of intestinal adaptation, the changes in small-bowel mucosal structure and function seen in lactation are problaby due to hormonal factors.
The Metabolism in Vivo and in Vitro of Plasma Low-Density Lipoprotein from a Subject with Inherited Hypercholesterolemia
Authors: Myant N. B. , Reichl D. , Thompson G. R. , Higgins M. J. P. , Galton D. J. 
Published: August 2015

1. The metabolism in vivo and in vitro of an abnormal low-density lipoprotein (LDL) obtained from a patient with an inherited form of hypercholesterolaemia was compared with that of LDL obtained from a normal subject.
2. The rates of turnover of the apoprotein of the two types of LDL in a normal subject, and their uptake and catabolism by normal lymphocytes in vitro, were similar.
3. It is concluded that the abnormal behaviour of the patient's LDL may not be due to an abnormality in the apoprotein component.
Inverse Relationship in Jamaica between Plasma High-Density Lipoprotein Cholesterol Concentration and Coronary-Disease Risk as Predicted by Multiple Risk-Factor Status
Authors: Miller G. J. , Miller N. E. , Ashcroft M. T. 
Published: August 2015

1. The relation between plasma high-density lipoprotein (HDL) cholesterol concentration and multiple coronary-risk factor status has been assessed in fifty-two middle-aged clinically healthy men from urban and rural Jamaica.
2. Rural hill-farmers had a superior exercise performance (assessed by the responses to submaximal test exercise), less body fat, and lower fasting levels for plasma total cholesterol, low-density lipoprotein (LDL) cholesterol, total triglyceride and blood glucose than urban businessmen. Mean plasma HDL cholesterol was considerably higher in farmers then businessmen.
3. Multilinear regression analysis showed HDL cholesterol concentration to be independently and inversely correlated with plasma triglyceride, LDL cholesterol and diastolic blood pressure and that these relationships applied across the urban and rural sub-groups. There was also some evidence that HDL cholesterol concentration increased with stature. When these factors were taken into account, age, ethnic group, adiposity, weight, exercise performance, smoking history and blood glucose made no further significant contribution to the prediction of HDL cholesterol concentration.
4. Thus plasma HDL cholesterol concentration was highest in those subjects with the lowest coronary-risk as predicted by their multiple risk-factor status, an observation which supported other evidence that coronary-risk is inversely related to plasma HDL concentration.
5. The results raise the possibility that coronary-risk can be more simply estimated from the plasma HDL cholesterol concentration than from a consideration of other major lipid risk factors and blood pressure.
Carbon Monoxide in Alveolar Air as an Index of Exposure to Cigarette Smoke
Authors: Rawbone R. G. , Coppin Catherine A. , Guz A. 
Published: August 2015

1. A rapid method for the analysis of CO in expired air has been developed, which is suitable for use in studies of smoking.
2. The Bohr equation has been used to calculate the mean alveolar CO partial pressure (Pa,co).
3. The values of Pa,co obtained are highly correlated with direct measurements of venous carboxyhaemoglobin (r = 0·96).
4. The method will distinguish between populations of smokers and non-smokers, and can allow the changes of CO in a smoker throughout a 12 h period to be followed. It provides a measure of the dose of cigarette smoke (vapour phase) that results from smoking a single cigarette.
Effects of Noradrenaline on Consecutive Vascular Segments at Low or Normal Calcium Concentrations in Control and Spontaneously Hypertensive Rats
Authors: Folkow B. , Hallbäck M. , Jones J. V. , Sutter M. 
Published: August 2015

1. An ‘isogravimetric’ technique, plus measurement of pressure in a small artery, was used to investigate the responses of upstream and downstream precapillary and postcapillary resistance vessels in the hindquarters of spontaneously hypertensive rats (SHR) and normal control rats perfused at constant flow.
2. Dose—response curves to noradrenaline were constructed under conditions of low or normal calcium.
3. In both control rats and SHR the dependence on external calcium during contraction increased peripherally, with the smaller pre- and post-capillary resistance vessels being most dependent and larger arteries least dependent.
4. There may be differences between SHR and control rats in regard to the handling of calcium, particularly in the small pre- and post-capillary resistance vessels.
Diminished Albumin Binding of Zinc in Serum of Pregnant Women
Authors: Giroux E. , Schechter P. J. , Schoun Josiane 
Published: August 2015

1. Distribution of zinc between the metalloprotein α2-macroglobulin and albumin was determined in samples of serum obtained from twenty-three women in their third trimester of pregnancy and eighteen women who were not pregnant.
2. The decrease observed in total serum zinc in the group of pregnant women could be accounted for in large part by a decreased concentration of albumin-bound zinc.
3. The concentration of serum albumin was lower in the pregnant women, thus hypoalbuminaemia, which is often invoked to explain hypozincaemia in pathological situations, may in part account for hypozincaemia in pregnancy.
4. The affinity of albumin for zinc added to serum from pregnant women was less than that of albumin from non-pregnant women. This was determined by competition experiments between albumin and glycine for zinc. Decreased affinity of serum albumin for zinc may also contribute to the hypozincaemia associated with pregnancy.
Assessment of Autonomic and Non-Autonomic Components of Resting Hindlimb Vascular Resistance and Reactivity to Pressor Substances in Renal Hypertensive Rabbits
Authors: Angus J. A. , West M. J. , Korner P. I. 
Published: August 2015

1. Hindlimb vascular resistance (HVR) was measured before and after pharmacological autonomic blockade in unanaesthetized renal cellophan-wrap hypertensive or normotensive rabbits with previously implanted Doppler ultrasonic flowmeters.
2. When the blood pressure was restored to resting values after autonomic block, the elevated resting HVR in the hypertensive rabbits was entirely accounted for by an increased non-autonomic component (i.e. HVR after block). If the pressure was not restored after block the autonomic component (i.e. resting HVR minus non-autonomic HVR) was overestimated and the non-autonomic component was underestimated.
3. During maximum vasodilatation the minimum HVR was significantly higher in the hypertensive rabbits than in the normotensive group, probably due to structural differences of resistance vessels.
4. Reactivity of the hindlimb bed to noradrenaline, angiotensin II and vasopressin injections was approximately twice as great in the hypertensive rabbits as in the sham-operated group, probably as a consequence of the structural changes.
Influence of Severe Potassium Depletion and Subsequent Repletion with Potassium on Muscle Electrolytes, Metabolites and Amino Acids in Man
Authors: Bergström J. , Alvestrand A. , Fürst P. , Hultman E. , Sahlin K. , Vinnars E. , Widström A. 
Published: August 2015

1. Two women with severe hypokalaemic alkalosis were investigated by means of muscle biopsy before and at the end of 2 and 3 weeks respectively of intense therapy with potassium chloride.
2. The muscle biopsy material was analysed for water, electrolytes, adenine nucleotides, phosphocreatine, free creatine, pyruvate, lactate, glycogen and free amino acids. The extra- and intra-cellular distribution of water, electrolytes and amino acids was calculated by the chloride method.
3. Both patients showed a marked loss of intracellular potassium and an increase in intracellular sodium concentration. The muscle magnesium content was also slightly decreased. After repletion with potassium chloride, muscle sodium and potassium became normal.
4. The contents of creatine phosphate, ATP, ADP, AMP, lactate and pyruvate were within normal limits, but the phosphocreatine/total creatine ratio was reduced. After repletion, a small change in the apparent creatine—phosphokinase equilibrium had occurred, suggesting a minor increase in intracellular pH.
5. The concentrations of the basic amino acids, lysine, arginine and ornithine were increased far above normal. The intracellular accumulation of arginine was much higher than the increase in lysine concentration and the histidine concentration was normal. This differs from findings in potassium-depleted rats, where the intracellular lysine concentration is much higher than arginine concentration and histidine is high as well. After potassium repletion the intracellular concentration of ornithine, lysine and arginine became normal in one case and decreased considerably in the other. An increased intracellular concentration of glutamate and glutamine was also observed after potassium repletion.
Changes in Vascular Smooth Muscle Sensitivity to Vasoconstrictor Agents induced by Corticosteroids, Adrenalectomy and Differing Salt Intake in Rats
Authors: Schömig A. , Lüth B. , Dietz R. , Gross F. 
Published: August 2015

1. Isolated hind limbs of rats were perfused and vascular smooth muscle sensitivity to noradrenaline, methoxamine and potassium chloride was measured and dose-response curves were obtained.
2. The sensitivity of vascular smooth muscle to noradrenaline is attenuated by adrenalectomy and low sodium diet; it is enhanced by corticosterone. High sodium diet or administration of deoxycorticosterone did not alter the dose—response curve significantly.
3. The increased sensitivity of vascular smooth muscle after corticosterone treatment is not related to changes in the contractile protein or alterations in the neuronal uptake and extraneuronal metabolism of noradrenaline.
4. These results suggest that the increased sensitivity in corticosterone-treated rats may be due to the number of receptors, receptor affinity to noradrenaline, or changes in the functional link between receptor and contractile apparatus.
Lowering of Blood Pressure, Plasma Renin Substrate, Cholesterol and Triglyceride by Portacaval Anastomosis in Rats Fed on a 60% Sucrose/5% Lard Diet
Authors: Edwards K. D. G. , Herz R. , Sealey J. E. , Bradley S. E. 
Published: August 2015

1. Portacaval anastomosis was carried out in ten rats fed on a 60% sucrose/5% lard diet, which induced moderate hypertriglyceridaemia, mild hypercholesterolaemia and normotension.
2. Plasma triglyceride was decreased to 45% of concentrations observed in ten pair-weighed control rats.
3. Plasma cholesterol concentrations were reduced to 58%, renin substrate to 70% and aortic blood pressure to 80% of control values by portacaval shunt surgery.
4. Individual blood pressures were directly related to plasma renin substrate concentrations.
Humoral Response and Blood Pressure Regulation during Hypercapnia and Haemorrhage in Dogs
Authors: Dusting G. J. , Staszewska-Barczak Janina 
Published: August 2015

1. The blood-bathed organ technique was used to study the release of catecholamines, angiotensin II and prostaglandin-like (PL) substances into the circulation during hypercapnia and after haemorrhage in anaesthetized dogs.
2. Elevated blood concentrations of noradrenaline, angiotensin II and prostaglandin-like substances have been detected during both experimental conditions.
3. The rise of arterial blood pressure during hypercapnia and after haemorrhage was associated with elevated concentrations of angiotensin II in the blood and could be abolished by inhibition of the angiotensin I-converting enzyme with SQ 20881.
4. The compensation of arterial pressure during both stresses was significantly impaired by release of prostaglandin-like substances; it could be restored by inhibition of prostaglandin biosynthesis with indomethacin.
5. The results indicate that activation of the renin—angiotensin system represents the major humoral mechanism for the maintenance of arterial pressure during hypercapnic acidosis and after haemorrhage.
Solitary Kidney and Ageing as Causes of Low Renin and Aldosterone Concentrations: Relevance to ‘Low-Renin’ Essential Hypertension
Authors: Gordon R. , Doran Freda , Thomas M. , Thomas Frances , Cheras P. 
Published: August 2015

1. As experimental models of reduced nephron population in man, (a) twelve men aged 15–32 years who had one kidney removed 1–13 years previously and (b) fourteen normotensive men aged 70–90 years were studied. Results were compared with those in eighteen normotensive men aged 18–28 years and eleven men aged 19–33 years with essential hypertension.
2. While the subjects followed a routine of normal diet and daily activity, measurements were made, after overnight recumbency and in the fasting state, of plasma volume and renin activity on one occasion in hospital and of blood pressure on five to fourteen occasions in the home. Blood pressure was also measured after standing for 2 min and plasma renin activity after 1 h standing, sitting or walking. Twenty-four hour urinary aldosterone excretion was also measured.
3. The measurements were repeated in the normotensive subjects and subjects in (a) and (b) above after 10 days of sodium-restricted diet (40 mmol of sodium/day).
4. The mean plasma renin activity (recumbent) in essential hypertensive subjects was higher than in normotensive subjects. In subjects of (a) and (b) above, it was lower than normotensive subjects, and was not increased by dietary sodium restriction in subjects of (a).
5. The mean aldosterone excretion level was lower in old normotensive subjects than in the other groups, and increased in each group after dietary sodium restriction.
6. Mean plasma volume/surface area was not different between the four groups and in normotensive, essential hypertensive and nephrectomized subjects but not subjects aged 70–90 years was negatively correlated with standing diastolic blood pressure.
Determination of Renin-Dependency and Sodium-Dependency in the Three Renin Sub-Groups of Essential Hypertension
Authors: Gavras H. , Ribeiro A. , Brunner H. R. , Gavras I. 
Published: August 2015

1. In all three renin sub-groups of essential hypertension, the state of sodium balance determines the degree of participation of the renin-angiotensin system in sustaining high blood pressure.
2. Even the low-renin type can become renin-dependent when sufficient sodium depletion has been achieved.
3. The main difference between patients of these sub-groups appears to be their variable capacity to become depleted of sodium under standard dietary regimens.
Increased Central Blood Volume: A Possible Pathophysiological Factor in Mild Low-Renin Essential Hypertension
Authors: Julius S. , Esler M. 
Published: August 2015

1. Patients with mild low-renin hypertension characteristically have increased central blood volume. The total blood volume is normal; the larger central blood volume reflects a shift of the blood from peripheral to central (cardiopulmonary) segments of the capacity system.
2. A relationship between central blood volume and plasma renin activity is demonstrable during tilting in normal and hypertensive subjects. In thirteen individuals there was a strong correlation between the decrease of the central blood volume and the increase in plasma renin activity in response to 12 min of 35° head-up tilt.
3. We propose that the elevated central blood volume causes greater stretch of cardiopulmonary mechanoreceptors and this in turn depresses renin release in mild low-renin hypertension.
The Haemodynamic Response to Salt and Water Loading in Patients with End-Stage Renal Disease and Anephric Man
Authors: Kim K. E. , Onesti G. , Delguercio E. T. , Greco J. , Fernandes M. , Swartz C. 
Published: August 2015

1. Patients with end-stage renal disease and anephric patients underwent expansion and depletion of body fluids with salt and water. This resulted in four different sequential haemodynamic patterns: (i) no significant increase in blood pressure; (ii) increase in blood pressure associated with a rise in cardiac output and no effect on total peripheral resistance; (iii) increase in cardiac output followed by a rise in blood pressure and total peripheral resistance; (iv) increase in total peripheral resistance and blood pressure without significant changes in cardiac output.
2. It is concluded that an initial rise in cardiac output is not necessary to increase blood pressure in either anephric man or patients with end-stage renal disease.
Renal Urinary Kallikrein in Normotensive and Hypertensive Rats during Enhanced Excretion of Water and Electrolytes
Authors: Croxatto H. R. , Albertini R. , Arriagada R. , Roblero J. , Rojas M. , Rosas R. 
Published: August 2015

1. Urinary kallikrein excreted by normal rats is significantly increased (P < 0·001) 2 h after: (a) water loading, (b) water loading plus frusemide, 0·27 mmol (10 mg) per rat, (c) salt loading. In water-loaded rats, 5 i.u. of renin strikingly reduced kallikrein excretion (P < 0·01) but considerably increased sodium excretion (P < 0·001).
2. Renal kallikrein, measured by its kininogenase activity within 2 h of water loading, was significantly increased (P < 0·05); after water loading and frusemide it was 40% decreased (P < 0·001) and after salt loading it was reduced by approximately 50% (P < 0·02). Renin did not change renal kallikrein.
3. Severely hypertensive (one-kidney) rats (blood pressure >150 mmHg) showed no increase of urinary kallikrein after water loading, although there was a marked natriuresis; in moderately hypertensive rats (blood pressure <150 mmHg) urinary kallikrein was only one-third of that observed in control normotensive rats, after an equal degree of water loading.
Urinary Kallikrein and Plasma Renin during the Reversal of Renovascular Hypertension in Rats
Authors: Gulati O. P. , Carretero O. A. , Morino T. , Oza N. B. 
Published: August 2015

1. Urinary kallikrein, sodium, potassium and water excretion, and plasma renin activity were measured before and during the reversal of experimental hypertension produced by unclamping the renal artery in rats.
2. Kallikrein excretion decreased significantly after unclamping, suggesting that it does not play a significant role in the reversal of hypertension.
3. A decrease in plasma renin activity coupled with a slight increase of sodium excretion was observed, indicating that these might participate in the reversal of hypertension.