bluuebunny/crossref_metadata_2025_split huggingface dataset:
RENAL TUBULAR REABSORPTION OF UREA IN SHEEP
Authors: Scott D. , Mason G. D. 
Published: December 2014

Renal tubular reabsorption of urea was studied in sheep fed diets containing either 2·7 or 0·88 per cent nitrogen but which were equal in the proportions of roughage to concentrate components and in energy.As the amount of urea filtered at the glomerulus increased through the range 54–1347 µmole/min the amount reabsorbed by the tubule increased proportionately. This relationship was not influenced by urine flow rate within the range 1·0–9·2 ml./min. At urine flow rates less than 1·0 ml./min percentage reabsorption of filtered urea increased as urine flow rate diminished, an effect which was more marked when the low‐N diet was fed compared to when the high‐N diet was fed. This difference did not appear to be related to differences in the absolute amount of urea filtered but rather to differences in nitrogen intake or metabolism. The mechanism by which reabsorption is increased is as yet uncertain.
THE CONTRIBUTION OF EFFUSED BLOOD TO THE PROTEIN CATABOLIC RESPONSE TO FRACTURE
Authors: Campbell Rosa M. , Cuthbertson D. P. 
Published: December 2014

Although injuries such as fracture of a long bone may lead to the effusion of a considerable amount of blood in the area of trauma, organization of the haematoma can play but a minor role in the increased urinary excretion of nitrogen and other catabolites which constitute the normal response to moderate or severe injuries in the well nourished man or lower animal at normal environmental temperatures (20–22°C) for the following reasons:(1) adrenalectomy but without supporting corticosteroid abolishes the catabolic response;(2) protein deprivation before injury also abolishes it;(3) an environmental temperature of 30°C reduces the normal response;(4) additional non‐protein sources of energy in the diet reduce the catabolic response;(5) infused blood is apparently not rapidly catabolized.If the organization of a haematoma in the fracture site was the main source of the extra nitrogen found in the urine, then conditions 1–4 should likewise have demonstrated the effect. The fact that they did not supports the view that the organization of the haematoma or the presence of infused whole blood play but a relatively small and/or slow part in the characteristic protein catabolic response to fracture.
RENAL REGULATION OF ACID EXCRETION IN THE RED DEER (CERVUS ELEPHUS)
Authors: Scott D. 
Published: December 2014

Hydrochloric acid was infused into the rumens of two red deer in experiments designed to study renal control of acid excretion. The deer were fed roughage diets and in control periods the urine was alkaline and was rich in bicarbonate and poor in phosphate. Infusion of HCl led to a fall in urine pH and to the disappearance of bicarbonate from the urine. Excretion of acid in the urine increased and nearly all of this was due to the increased excretion of ammonium ions. Excretion of calcium in the urine increased appreciably during acid infusion and was correlated with urine pH. Excretion of sodium in urine was slightly increased during acid infusion and that in faeces was slightly reduced. Faecal excretion of calcium, phosphorus and potassium were unaffected.These results indicate that renal control of acid excretion in the red deer is similar to that of sheep and calves.
RENAL EXCRETION OF ACID AND BASE IN THE PIG
Authors: Scott D. 
Published: December 2014

Pigs fed a meal diet excreted between 100 and 200 m‐equiv/day of acid in the urine and about one‐third of this acid was present as titratable acid phosphate and the remainder as ammonium ions.Acidosis, produced by giving NH4Cl in the food or infusing HCl intravenously, increased the urinary excretion of acid, and nearly all of this increase appeared as ammonium ions without increased excretion of phosphate.Acidosis also increased urinary excretion of calcium and sodium but excretion of potassium was not affected. Few changes in faecal mineral excretion occurred during acidosis although sodium excretion was reduced.Ingestion of sodium bicarbonate increased urine pH and urinary excretion of bicarbonate but reduced the excretion of calcium in urine.These results suggest that renal control of acid and base excretion in the pig is similar to that in man and the dog.
CARDIOVASCULAR RESPONSES IN RABBITS OF DIFFERENT AGES TO HYPERTENSIN AND ADRENALINE
Authors: Pipkin Fiona Broughton 
Published: December 2014

In intact rabbits from birth to maturity, the rise of arterial pressure on intravenous injection of hypertensin, adrenaline and vasopressin (doses calculated per kg body weight) was used as an index of cardiovascular sensitivity. On this basis, sensitivity to hypertensin fluctuated with age but was similar at birth and in adults; in contrast, sensitivity to adrenaline and vasopressin decreased progressively with age.The ganglion and adrenal medullary blocking agent presidal caused a progressively greater increase in sensitivity to injected hypertensin in older than in younger rabbits. Baroreceptor nerve section caused proportionately similar increases in sensitivity at all ages.Acute nephrectomy caused a fall of 54 per cent in resting arterial blood pressure in newborn rabbits, but only 16 per cent in adults; this contrasted with falls of 1 per cent and 10 per cent respectively in dummy operations.These observations are consistent with the view that the autonomic nervous system is not fully developed in the newborn rabbit. At this age the renin‐angiotensin system appears to be of relatively greater importance than in the adult.
A COMPARISON OF DIGESTION IN RED DEER AND SHEEP UNDER CONTROLLED CONDITIONS
Authors: Maloiy G. M. O. , Kay R. N. B. 
Published: December 2014

Three red deer hinds and three sheep were given rations of chopped or pelleted hays. The deer apparently digested dry matter and cellulose a little less well than the sheep. Digestibility of nitrogen did not differ.In two pairs of animals fitted with rumen cannulas the volume and outflow of rumen fluid was greater in the deer than in the sheep. The pH and the concentrations of total and individual volatile fatty acids and of ammonia in the rumen fluid varied during the feeding cycle in much the same way in the deer and sheep. The rumen fluid of the deer seemed to be a little less well buffered than that of the sheep.It is concluded that digestive processes in the deer, as far as revealed in these experiments, quite closely resemble those in the sheep, though certain small differences may exist.
THE EFFECTS OF ENDOGENOUS AND ADDED INSULIN ON THE TIME‐COURSE OF GLUCOSE UPTAKE BY THE ISOLATED PERFUSED RAT HEART
Authors: Fisher R. B. , 'me>O'Brien J. A. 
Published: December 2014

A new method for measurement at short intervals of uptake or production of metabolites by a perfused heart has been applied to the study of the time‐course of glucose utilization. In the presence of high concentrations of insulin (100 mU/ml.) glucose utilization was constant from the beginning of perfusion at all concentrations of glucose. In the absence of added insulin, when the perfusate glucose concentration was greater than 1 mM, glucose utilization decreased by more than 20% to reach a constant rate after up to one hour of perfusion. At glucose concentrations below 0·5 mM, glucose utilization without insulin was constant, or nearly so, throughout perfusion. These results suggest that endogenous insulin, which may be relatively ineffective in promoting glucose utilization at low glucose concentrations, influences the properties of the isolated heart longer than is generally supposed.By choice of a suitable infusion rate it is possible to use the new method to study metabolic rates at substrate concentrations which it was not previously feasible to use.
AMINO ACID AND GLUCOSE UPTAKE BY THE ISOLATED PERFUSED GUINEA‐PIG MAMMARY GLAND
Authors: Davis S. R. , Mepham T. B. 
Published: December 2014

A technique has been developed for perfusion of the isolated guinea‐pig mammary gland. Perfusate flow rates per unit weight of tissue were similar to in vivo mammary blood flow in lactating rats and 2–3 times mammary blood flow in the lactating cow and goat.Amino acid uptake was measured by the arterio‐venous difference technique. The uptake of ‘essential’ amino acids correlated with their relative content in guinea‐pig milk protein, but uptake of ‘non‐essential’ amino acids was insufficient to account for the predicted rate of protein synthesis. Uptake of most amino acids was dependent on the rate of supply of exogenous substrates. Glucose uptake was variable but mean uptake during perfusion correlated with the rate of substrate infusion and gland weight. After addition of [U‐14C]glucose to the perfusate in one experiment, alanine, serine, glutamic acid, aspartic acid and proline residues in milk casein became significantly labelled.The maintenance of high perfusate flow rates was found to depend on the attention paid to filtration of the perfusate, but the rate of amino acid uptake was probably dependent on the availability of tryptophan.
THE OXYGEN CONSUMPTION, FATTY ACID AND GLYCEROL UPTAKE OF THE LIVER IN FED AND FASTED SHEEP DURING COLD EXPOSURE
Authors: Thompson G. E. , Gardner J. W. , Bell A. W. 
Published: December 2014

The effect of a short period (3—4 hr) of exposure to cold on the liver's circulation and metabolism has been studied in sheep fed 6 hr or 21 hr before experiment.In the cold the animals had a significantly increased heart rate, cardiac output, hepatic portal blood flow, mean arterial blood pressure and pulse pressure. Total peripheral resistance fell in the fasted animals when they were exposed to cold, but not the more recently fed animals. Exposure to cold significantly increased the total body oxygen consumption and oxygen consumption of the liver, but not that of the portal‐drained viscera (gut, spleen, pancreas, omental adipose tissue). Recent feeding significantly increased the net rate of release of volatile fatty acids from the portal‐drained viscera, and significantly increased their net rate of uptake by the liver. In the recently fed animals, exposure to cold further increased the visceral release, portal plasma concentration, and hepatic uptake of volatile fatty acids. Exposure to cold, and fasting, both significantly increased the circulating (arterial) plasma level of free fatty acids and glycerol, and increased their net rate of uptake by the liver, significantly in cold exposure but not in fasting.The results show that the liver makes a small contribution to the total increase in oxygen consumption in the cold. The liver also has an increased uptake of fatty acids and glycerol during cold exposure.
CHANGES IN BLOOD COMPOSITION AND IN URINARY MINERAL EXCRETION IN THE PIG IN RESPONSE TO ACUTE ACID‐BASE DISTURBANCE
Authors: Scott D. , Mcintosh G. H. 
Published: December 2014

Young pigs (about 25 kg) were given intravenous infusions of hydrochloric acid or sodium bicarbonate to produce acute variations in blood pH. Infusion of acid resulted in increased excretion of calcium, magnesium, sodium, potassium, chloride and ammonia in the urine. The concentrations of potassium and chloride in the plasma were increased while those of calcium and phosphorus were reduced. Infusion of alkali produced few changes in urinary mineral excretion: potassium being increased and ammonia reduced. Changes in the plasma in response to alkali infusion included an increase in sodium concentration and a fall in the concentrations of potassium and chloride.Normal values for blood pH, pCO2 and base excess found in the pigs used in these studies were all higher than those considered to be normal in both man and dog. Renal bicarbonate threshold in the pig was also higher than in those other species in that little or no bicarbonate appeared in the urine until the concentration of bicarbonate in the plasma exceeded 31—32 mmol/l.
THE EFFECT OF THE ANIONS, PHOSPHATE AND SULPHATE, ON NORMAL RATES OF EXCRETION OF POTASSIUM IN DOGS
Authors: Baylis Christine , O'Connor W. J. 
Published: December 2014

Small doses of (NH4)2HPO4 or KH2PO4 by stomach tube caused increase in plasma PO4 and PO4 excretion. Above a threshold of 0·8 mmol.l–1, increase of plasma PO4 by 0·5 mmol.l–1 caused PO4 excretion to increase by about 35 µmol.min.–1 After KH2PO4 this relationship was not altered by the concurrent increases in plasma K and K excretion. After doses of (NH4)2SO4 or K2SO4, excretion of SO4 was similarly related to plasma SO4 and was independent of plasma K and K excretion.An effect of PO4 on K excretion was observed after doses of (NH4)2HPO4, when increased excretion of PO4 was accompanied by increased excretion of K without change in plasma K. There was also increased excretion of NH4 and a small increase in Na excretion. The changes were similar to those produced by (NH4)2SO4 [O'Connor and Summerill, 1976].KH2PO4 and K2SO4 produced increase in plasma K and increased excretion of K not significantly different from the changes produced by KCI or KHCO3 [Baylis and O'Connor, 1976]. After KH2PO2 or K2SO4, the urinary anion was PO4 or SO4, instead of Cl and HCO3. Any effect of anions on K excretion was much less than the effect of increase in plasma K.At low rates of excretion of K, increased urinary excretion of impermeant anion can determine increased excretion of K. However, the effect of anion is small in comparison with the effect of increase in plasma K.
THE EFFECT OF HYPOXIA ON MUSCLE GLYCOGEN RESYNTHESIS IN MAN
Authors: Milledge J. S. , Halliday D. , Pope C. , Ward P. , Ward M. P. , Williams E. S. 
Published: December 2014

The effect of hypoxia and muscle fibre type on the resynthesis of muscle glycogen was studied in three healthy subjects by means of needle biopsies. Biopsies were taken before and after exercise and after 5 h recovery. In control experiments subjects breathed air during the recovery phase whereas in the test experiments they breathed 10% oxygen in nitrogen during this time. Diet was controlled throughout the experiments and provided an excess of carbohydrate. Biopsies were assayed for total muscle glycogen and were studied histochemically, using microdensitometry on PAS stained sections as a measure of glycogen in individual fibres.Exercise depleted muscle glycogen to a mean of 26% of control values. After 5 h recovery the mean values had risen to 62% breathing air and 51% on 10% oxygen breathing but this difference was not significant. In biopsies taken after 5 h recovery breathing either air or 10% oxygen, there was a marked contrast in PAS staining between muscle fibre Type I and II, the Type II fibres being more heavily stained. This difference was confirmed by microdensitometry. The contrast was increased by hypoxia in all subjects but this effect did not reach levels of statistical significance.It is concluded that under these experimental conditions the overall resynthesis of muscle glycogen is not significantly affected by hypoxia. It is shown that Type II fibres resynthesise significantly more rapidly than Type I under both normoxic and hypoxic conditions. Hypoxia may enhance this difference in rate of resynthesis.
THE MITOTIC ACTIVITY OF BLOOD MONOCYTES CULTURED IN AUTOLOGOUS WOUND FLUID
Authors: Greenwood B. 
Published: December 2014

Wound fluid was obtained from the subcutaneous tissue of sheep by implanting a perforated Teflon sampling chamber. A catheter from this chamber was brought to the surface.The types and numbers of cells in this fluid were recorded. Cell free fluid was used at either 100% concentration, or 25% concentration in plasma, as a medium for the culture of autologous blood monocytes. Its ability to support mitosis was compared with that of 100% autologous plasma. Wound fluids taken upon consecutive post‐implantation days were compared.Cultured monocytes survived in small numbers in wound fluid collected on the days immediately following operation. When mitosis occurred the mitotic indices remained low. The wound fluid did not exhibit that mitogenicity which is apparent in autologous plasma taken on the third or fourth days following implantation.The results suggest that, following the implantation of Teflon, the wound fluid contains a component which is toxic for blood monocytes cultured upon glass.
IRON METABOLISM IN PIGEONS
Authors: Ramis J. , Planas J. 
Published: December 2014

Several haematological parameters such as haemoglobin concentration, haematocrit, erythrocyte number, reticulocyte concentration, plasma iron and total iron binding capacity were determined in 118 urban pigeons of both sexes. No statistically significant sex differences among these parameters were found. In 36 specimens (23 males and 13 females), the plasma iron turnover was determined using 59Fe. The results obtained in this species, expressed per 100 ml−1 blood. day−1 and Kg−1 body weight. day−1, were compared with those of turkeys, ducks and chickens calculated from earlier papers. The highest values versus body weight were observed in pigeons.Organ (liver, spleen, tibia, heart, leg muscle, ribs, sternal keel, gonads and blood) distribution of 59Fe intravenous injection was analyzed during a period from 5 min up to 120 days (19 different times) in groups of 4 pigeons. At the 6 h period, the organs retained the highest dose (20% of total Fe injected), but by the 2nd day period, the radioiron in the blood represented about 98% of the total injected. A fast iron uptake by the circulatory blood was checked and compared with that of other species (domestic fowl, ducks and turkeys). The reticulocyte count in pigeons normally ranged from 4 to 12%, which was consistent with these results. A linear decreasing radioactivity in blood, with an inflexion point on the 40th day was observed. An inverse correspondence between blood and liver was found. Content in other organs decreased uniformly with time, except the heart where the iron content was practically constant during the whole time. Ribs and sternal keel are erythropoietic organs in young pigeons.
Oxygen Consumptions and Potassium Contents of Slices of Rat Renal Cortex
Authors: Cooke K. R. 
Published: December 2014

An oxygen electrode respirometer for determining the oxygen consumption of slices of mammalian renal cortex is described and assessed.Though rat renal cortical slices incubated in potassium‐free medium for one hour lost 102 + 14 mmol of potassium/kg dry weight, there was only a small, nonsignificant fall in oxygen consumption. In contrast the oxygen consumption of slices incubated in potassium‐free medium with 10 mmol.l–1 ouabain was markedly reduced ( by 32 ± 6%), while such slices lost 180+15 mmol of potassium/kg dry weight. These disproportionate effects on potassium loss and inhibition of oxygen consumption suggest that in renal cortical slices the loss of potassium in low potassium medium is not primarily due to inhibition of the conventional sodium pump.
The Effects of Colchicine on Milk Secretion, Mammary Metabolism and Blood Flow in the Goat
Authors: Henderson A. J. , Peaker M. 
Published: December 2014

Mammary function in the conscious goat was studied during colchicine‐induced depression of milk secretion in one mammary gland. Milk yield of the treated gland was reduced to approximately a quarter of previous, while where were significant increases in afternoon milk yield from the untreated glands on the 2nd and 3rd days after treatment in goats in late lactation. Milk composition in the untreated glands was not significantly affected. In the treated gland, milk [Na+], [Cl+], [citrate] amd [protein] increased while [K+] and [lactose] decreased, although the time course of these changes differed; milk [fat] was unaffected.Mammary extractions ((A‐V)/A) of glucose, acetate and most amino acids were significantly decreased during the period of maximal inlibition of secretion. There were no significant changes in arterial plasma concentrations of glucose, acetate or any essential amino acids. In another series of experiments, mammary blood flow increased and then returned to normal after colchicine treatment even though milk yield and mammary glucose uptake decreased markedly; oxygen uptake was not significantly affected.The results are discussed in relation to the actions of colchicine on the mammary secretory cell, to the normal control of mammary blood flow and to the mechanism of compensation by the untreated gland.
REPRODUCTIVE BEHAVIOUR IN THE PIG AFTER AUTOTRANSPLANTATION OF THE OVARY BY VASCULAR ANASTOMOSES
Authors: Harrison F. A. 
Published: December 2014

Orthotopic autotransplantation of the left ovary with vascular anastomoses to the aorta and vena cava on the right side of the abdomen of a gilt, in which the right ovary had been removed, was followed by normal cyclic activity ofthe transplanted ovary and the successful establishment, maintenance and completion of pregnancies of normal gestational length, with apparently normal lactation.Heterotopic autotransplantation of the left ovary with vascular anastomoses to major vessels in the neck in two sows, in which the other ovary had been removed, was also followed by cyclic ovarian activity of normal length with normal sexual behaviour. The observations suggest that, in the pig, the uterine luteolysin is capable of acting by a vascular route independent of local connexions.
THE DENSITY AND DISTRIBUTION OF CAPILLARIES AROUND A SYNOVIAL CAVITY
Authors: Knight A. D. , Levick J. R. 
Published: December 2014

The interpretation of trans‐synovial fluxes requires a knowledge of the number of capillaries present around the joint cavity, and their depths below the surface of the joint lining. Measurements of capillary numbers, depths and dimensions were therefore carried out by light microscopy on synovial tissue sections from five rabbit knees. In addition the surface area of synovial tissue lining the joint was estimated, and the thickness of the synovium measured. Synovial capillary density was found to be uneven, with respect to both anatomical location in the joint cavity and depth below the synovial surface. The large area of synovium over areolar or adipose tissue was highly vascular (67000–83000 capillaries.cm−2 section; mean intercapillary distance 35–55, µm; 228–329 cm2 endothelium.cm−3 synovium). The small area of synovium over tendons was of very low vascularity (2000 capillaries.cm−2 section). From these data and a previous estimate of net filtration capacity, mean synovial endothelial conductivity was estimated as ∼ 16 x 10−7 cm.s−1.mmHg−1. The depth distribution of the capillaries was extremely skewed, with a sharp peak at 6–11 µm depth. The rapid decay in capillary density at depths 〉 6–11 µm was partly due to an uneven density of capillaries within the synovium itself; and partly due to a lower density in subsynovial tissues.It was concluded that most synovium has a rich capillary bed which is very superficially located and that the depth of periarticular tissue which is effective in exchange processes with the joint cavity is less than 25 µm.