bluuebunny/crossref_metadata_2025 huggingface dataset:
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.
THE INFLUENCE OF CHRONIC ADMINISTRATION OF PENTAGASTRIN ON THE RAT PANCREAS
Authors: Mayston P. D. , Barrowman J. A.
Published: December 2014

Chronic administration of pentagastrin to rats results in hypertrophy of the acinar cells of the pancreas. This hypertrophy is accompanied by a decrease in the specific activities of pancreatic enzymes of the tissue in terms of protein content, and an increase in the RNA : DNA ratio of the tissue. An increase in weight of a duodenal segment has also been observed. The suggestion is put forward that the tetrapeptide, Try‐Met‐Asp‐Phe‐NH2, the sequence occurring at the carboxyl terminus of gastrin and cholecystokinin, may exert a trophic influence upon several tissues of the upper gastrointestinal tract.
ACTION POTENTIAL MODIFICATIONS IN RAT MYOCARDIAL CELLS DURING VITAMIN A DEFICIENCY
Authors: Rindi G. , Ventura U. , Ceriani T. , Zelaschi F.
Published: December 2014

In volume 55 of this Journal (1970), page 334, delete first three lines and substitute:
MECHANICAL AND CHEMICAL CONTROL OF BREATH HOLDING
Authors: Kelman G. R. , Wann K. T.
Published: December 2014

The relationship between the maximum duration of a voluntary breath hold (BHT) and the alveolar Pco2 at the start and finish of the period of apnoea has been investigated in six subjects over a wide range of CO2 tensions, for breath holds made at VC, 60 per cent VC, and FRC. Alveolar Po2 was maintained above the level at which hypoxia is a significant factor in stimulating pulmonary ventilation. The results suggest that the relationship between BHT and Pco2 at breaking point may be approximated by two straight line segments: for short breath holds (with a high initial Pco2), BHT and breaking point Pco2 are linearly related; for long breath holds (with a low initial Pco2) final Pco2 is independent of the duration of the breath hold. These results suggest that the mechanical component of the drive to resume breathing saturates during long breath holds, the level of saturation depending on the lung volume at which the breath is held.
ACTION POTENTIAL MODIFICATIONS IN RAT MYOCARDIAL CELLS INDUCED BY HYPERVITAMINOSIS A
Authors: Ventura U. , Ceriani T. , Zelaschi F. , Rindi G.
Published: December 2014

Ventricular cell action potentials were measured in situ using intracellular microelectrodes in the hearts of hypervitaminotic A rats, both at the spontaneous rate and at rates externally increased to various higher levels. The action potentials were much modified (decrease in amplitude, in depolarization rate, in fast and slow repolarization rate, and increase in partial and total duration). Excess of vitamin A also appeared to bring about a rise in spontaneous heart rate. Ion fluxes in myocardial cells at high levels of vitamin A seemed to be somewhat uncoupled from cardiac metabolism. The results obtained indicate that the changes in cardiac electrogenesis may be specifically related to the effects of an excess of vitamin A on cell membrane structure and consequently on permeability and ion fluxes through the membranes.
FETAL‐MATERNAL PLASMA CALCIUM RELATIONSHIPS IN THE RABBIT
Authors: Graham R. W. , Porter G. P.
Published: December 2014

Plasma total calcium levels have been studied in pregnant rabbits and their fetuses from 16 days gestation to term. Between 16 and 21 days gestation the observed fetal plasma calcium level falls from the maternal level or above to 1·6 mg/100 ml. below the maternal level. Thereafter, the fetal plasma calcium rises and at 30 days gestation exceeds the maternal level by 1·9 mg/100 ml. There is a high correlation between fetal and maternal levels at 21 days which is lost by 30 days. Fetal skeletal calcification was studied using an alizarin stain technique. The earliest centres of calcification were present in the clavicle and mandible at 16 days. It is concluded that the observed fall in fetal plasma calcium near mid‐gestation may be due to the onset of skeletal calcification and the increase after 21 days to one or more of a variety of factors. Five 21 days pregnant animals were infused with 1 per cent calcium chloride solution (1 g anhydrous calcium chloride in 100 g aqueous solution) for up to 2½ hr. The maternal plasma calcium concentration was elevated by 7·7 mg/100 ml. during the infusion but the fetal level was only raised by 2·0 mg/100 ml. The correlation between fetal and maternal levels was lost during the infusion. These findings are compatible with either slow calcium transfer across the placenta or fetal calcium homeostasis.
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.
CONTRACTION OF CHICKEN RECTUM TO NERVE STIMULATION AFTER BLOCKADE OF SYMPATHETIC AND PARASYMPATHETIC TRANSMISSION
Authors: Bartlet A. L. , Hassan T.
Published: December 2014

The longitudinal muscle of an isolated Remak nerve‐rectum preparation from the chicken responded to nerve stimulation with a contraction or, when the tone of the preparation was raised by acetyl‐β‐methylcholine (11·0 mM), with a contraction followed by a relaxation. The relaxation of the preparation was unaffected by hexamethonium, antagonized by bretylium, blocked by a combination of propranolol and phentolamine at specific concentrations and was absent or diminished in reserpinised preparations. The contraction was abolished by hexamethonium or tubocurarine and was partially antagonized by hyoscine.
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.
RECEPTORS, ACTIVATED BY ACID, IN THE DUODENAL WALL OF RABBITS
Authors: Andrews C. J. H. , Andrews W. H. H.
Published: December 2014

In anaesthetized rabbits, the effect of introducing acid into the lumen of the duodenum on the frequency of action potentials in the afferent nerves was investigated. Hydrochloric acid, 0·1 and 0·05 M, and acid sodium citrate, buffered with hydrochloric acid to a pH of less than 2, induced action potentials in the distal portions of cut mesenteric nerves coming from the part of the duodenum exposed to the acid. Two types of response were noted from the upper part of the duodenum. One consisted of an intense volley of action potentials beginning almost immediately and lasting for about 15 sec. The other response was less intense; it reached its maximum in about 30 sec and lasted for periods of at least 90 sec. It is postulated that there are two types of nerve receptor in the wall of the duodenum of rabbits which may be stimulated by acid in the lumen, and evidence is presented in favour of the suggestion that the concentration of hydrogen ions is the important factor. The relationship of acid in the duodenum to inhibition of gastric secretion is discussed.
EVAPORATIVE COOLING IN THE RAT: INTERACTION WITH HEAT LOSS FROM THE TAIL
Authors: Stricker Edward M. , Hainsworth F. Reed
Published: December 2014

There are two major thermolytic responses of rats to inescapable heat stress: cutaneous vasodilatation and grooming behavior. The former response increases heat loss by radiation, conduction, and convection, primarily from vascularized exposed surfaces such as the tail, and depends upon the positive thermal gradient between the rat and its environment that occurs at ambient temperatures of 32–40°C. The latter response increases heat loss by evaporation of saliva groomed onto body surfaces and becomes increasingly important as ambient temperatures approach 40–41°C and the positive thermal gradient diminishes. These two mechanisms are not independent of one another. For example, rats develop more pronounced hyperthermia following surgical removal of salivary function, thereby increasing the positive thermal gradient and facilitating heat loss. Similarly, rats increase evaporative cooling by salivary grooming following amputation of the tail. Removal of either saliva or the tail impairs the rat's ability to regulate body temperature, while removal of both leaves the rat most vulnerable to heat stress.
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 OXYGEN CONSUMPTION OF THE UTERUS AND ITS TISSUE CONTENTS IN LATE GESTATION: A COMPARISON OF SIMULTANEOUS MEASUREMENTS USING TWO DIFFERENT TECHNIQUES
Authors: Clapp James F. , Abrams Robert M. , Caton Donald , Cotter Julian R. , Barron Donald H.
Published: December 2014

The oxygen consumption (ml./kg/min) of the pregnant uterus and its contents has been estimated in near term ewes by two methods based on different assumptions and techniques: (1) by equating it with the decrease in the oxygen consumption of the ewe which followed occlusion of the uterine circulation, and (2) as the product of the (A‐V)O2 across the uterus and the rate (ml./kg/min) of uterine blood flow estimated by the diffusion equilibrium method. The results obtained by these two methods are in good agreement. The mean value obtained by each method was 9·2 ml./kg/min.
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.
PROPERTIES OF FAST AND SLOW MOTOR UNITS IN HIND LIMB AND TAIL MUSCLES OF THE RAT
Authors: Andrew B. L. , Part N. J.
Published: December 2014

The nerve conduction velocities and motor unit contraction properties of forty‐one hind limb motor units (soleus, 37; extensor digitorum longus, 4) and twenty‐nine motor units from the mid‐tail lateral segmental muscles of the rat were measured. The motor units of the soleus were found to form an homogeneous group as judged by contraction time with just one particularly slowly contracting unit. In the soleus muscle a negative correlation between conduction velocity of the nerve fibre and contraction time of the motor unit was found but no significant correlation between conduction velocity of the nerve fibre and the tetanic tension of the motor unit. The motor units of the tail muscleswere found to form two distinct groups, one of fast units and the other of slow units. In the tail muscles, the slowly conducting motor nerves innervated the slowly contracting units and the fast conducting nerves the fast contracting units. A relationship between the tetanic tension of the tail muscle motor units and nerve conduction velocity was demonstrated.
THE VELOCITY OF ERYTHROCYTES IN A HEPATIC SINUSOID, AND THE EFFECT OF INTRAPORTAL INJECTION OF ADRENALINE
Authors: Cheng Kwok‐kew , Ho Margaret Suet‐lee , Ma Ying‐ping
Published: December 2014

A method for measuring the velocity of erythrocytes in the hepatic sinusoids of the rat is described. The liver is immobilized by the use of a diaphragmatic screen and a cover glass over the anterior edge of the liver which adheres by surface tension. The liver is transilluminated by light transmitted through a flexible optical fibre guide. Erythrocyte velocity is measured by continuous photometry of the magnified microscopic image of a hepatic sinusoid; two adjacent phototransistors generate signals as the images of red cells pass them, and the erythrocyte velocity is determined from the time difference in the two signals. Intraportal injection of adrenaline caused a significant increase in the velocity.
THE TIME COURSE OF THE DIURETIC RESPONSE TO LEFT ATRIAL DISTENSION
Authors: Lawrence M. , Ledsome J. R. , Mason J. M.
Published: December 2014

Distension of the left atrium for a 30 min period causes an increase in urine flow, osmolal clearance and free water clearance. The present experiments examine in detail the changes in urinary excretion during a 90 min distension of the left atrium. The experiments demonstrate that in anaesthetized dogs when distension of the left atrium is continued for a 90 min period the increases in urine flow, solute excretion, and free water clearance are transient. Urine flow, free water clearance, and urine osmolality returned completely to control values only after release of left atrial distension. In contrast, solute excretion returned to control values 40 min after the start of left atrial distension and was independent of any concurrent changes in the dilution of the urine. The results support the hypothesis that the diuretic response to left atrial distension is dependent upon two mechanisms: a decrease in the rate of release of antidiuretic hormone from the neurohypophysis, which may be prolonged; and a haemodynamic mechanism which under the conditions of the present experiments appears to be short lived.
FATTY ACID COMPOSITION OF TISSUE LIPIDS IN CHOLINE DEFICIENT RATS
Authors: Chahl J. S. , Kratzing C. C.
Published: December 2014

Rats fed a choline deficient diet for three weeks had up to 38% of their liver weight in lipids, compared with 6·5% in choline supplemented controls. This large increase in liver lipids was due to an accumulation of triglycerides, whose fatty acid composition was not altered in choline deficiency although the plasma triglyceride concentration of stearic acid was increased and that of oleic acid was decreased. In choline‐deficient rats, the concentration of arachidonic acid was decreased in liver phospholipids while that of docosapolyenoic acids was increased. There were more widespread changes in the cholesterol ester fatty acids of liver and plasma in choline deficient rats. It is proposed that selective impairment of transport of lipid species, depending on fatty acid composition, occurs in choline deficiency.
AN ASSESSMENT OF THE PHYSIOLOGICAL IMPORTANCE OF THE LARGE HEPATIC VENOUS SLUICES IN THE DOG
Authors: Andrews W. H. H. , Ritcme H. D. , Maegraith B. G.
Published: December 2014

Experiments were carried out on isolated canine livers perfused through the hepatic artery and portal vein with blood diluted with Ringer‐Locke solution. Part of the out‐flow was collected from a stiff‐walled catheter which had been wedged in a small tributary of the hepatic venous vein tree and the rest of the outflow was collected from the vena cava. These two collections were measured separately, and it was shown by the injection of histamine, the injection of acetylcholine or by the production of anaphylaxis that an injection which decreased one outflow decreased the other by the same proportional amount. Since the main outflow passed the ostia and would therefore have been impeded had the ostial sphincters constricted strongly it appears that, contrary to reports, the ostial sphincters do not contribute materially to canine hepatic venous resistance. Further experiments in vivo were also carried out where the flow from a wedged hepatic venous catheter was measured. Intraportal injections of acetylcholine and histamine reduced the catheter outflow and it is thought that the small hepatic veins therefore may regulate hepatic venous outflow. It is suggested that the large hepatic veins may function as a small, labile hepatic blood reservoir.
THE EFFECT OF INTRAVASCULAR INJECTIONS OF VERATRINE ON LARYNGEAL RESISTANCE TO AIRFLOW IN CATS
Authors: Szereda‐Przestaszewska Malgorzata , Widdicombe J. G.
Published: December 2014

Changes in laryngeal resistance to airflow have been measured in cats during spontaneous breathing through the larynx, and while the larynx was isolated in situ with constant airflow. Intravenous injections of veratrine resulted in apnoea with a large increase in laryngeal resistance, followed by expiratory increases in laryngeal resistance. These responses were abolished by cutting the vagi in the chest and were absent on injection of veratrine into the left atrium, which established the pulmonary nerves as the main afferent pathway for the reflex. It is concluded that stimulation of pulmonary receptors constricts the larynx.
THE EFFECTS OF PROSTAGLANDINS E2, A2 AND F2α ON CAROTID BARORECEPTORS AND CHEMORECEPTORS
Authors: McQueen D. S. , Belmonte C.
Published: December 2014

The actions of prostaglandins E2, A2 and F2α on the sensory receptors of the carotid bifurcation have been investigated. Electrical activity of baroreceptor and chemoreceptor fibres was recorded from the sinus nerve of anaesthetized cats. Prostaglandins elicited alterations in blood pressure which were accompanied by changes in baroreceptor activity. Chemoreceptor spontaneous activity was modified by the injection of prostaglandins; such variation did not occur in vitro and thus appears to be secondary to changes in carotid blood flow. We have been unable to demonstrate any action of the prostaglandins at the concentrations studied on baroreceptors or chemoreceptors of the carotid bifurcation, apart from changes secondary to vascular effects.
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.
ORIGIN AND FORMATION OF LYMPH LIPIDS IN THE SHEEP
Authors: Leat W. M. F. , Harrison F. A.
Published: December 2014

3H and 14C‐labelled palmitic, stearic, oleic, linoleic and linolenic acids introduced into the duodenum of sheep were recovered in thoracic duct lymph, and the specific radioactivities of the fatty acids in the various lipid fractions were determined. Lymph fatty acids were transported mainly as triglycerides (77%) and phospholipids (18%), probably mostly in the form of very low density lipoproteins rather than as chylomicrons. Lymph triglycerides transported most of the palmitic, stearic and oleic acids (74–79%) whereas phospholipids were important in the transport of the essential fatty acids, linoleic and linolenic acids (54% and 38% respectively). Specific radioactivity measurements indicated that part of the lymph cholesteryl ester and phospholipid fatty acids were of a non‐radioactive origin. In lymph phospholipids 52% of the linoleic acid, 81% of the linolenic acid and more than 88% of the palmitic, stearic and oleic acids were derived from endogenous esterified sources. Evidence is presented to indicate that the major part of lymph phospholipids could be derived from biliary phospholipid. The possible roles of bile and pancreatic juice in fat absorption in the ruminant are discussed.
REGULATION OF BILE FORMATION IN RABBITS AND GUINEA PIGS
Authors: Shaw H. M. , Heath T. J.
Published: December 2014

Despite interruption of the enterohepatic circulation of bile salts, bile flow in conscious rabbits and guinea pigs remained constant for several hours when saline was infused to compensate for loss of water and electrolytes in bile. Thus it appeared that biliary flow in these species is not as highly dependent on bile salt secretion as it is in dogs and man. The effects of other stimulants known to play an important role in regulating bile formation in other species were tested in rabbits and guinea pigs. Secretin, cholecysto‐kinin‐pancreozymin (CCK‐PZ) and gastrin proved to be ineffective choleretics in rabbits although the doses of these exogenously‐administered hormones were sufficient to significantly increase either pancreatic or gastric secretion. Trivial choleretic responses were recorded after administration of secretin and CCK‐PZ to guinea pigs. Attempts were then made to elicit a choleresis by release of endogenous hormones. Again no changes in bile formation were recorded in rabbits although pancreatic secretion was stimulated. Bile flow in guinea pigs increased slightly, but the degree of duodenal acidification necessary to produce all of these responses to endogenous secretin release was probably unphysiological. Attempts to stimulate the release of endogenous CCK‐PZ by infusing peptone were unsuccessful. It was concluded that if these herbivores do elaborate secretin and CCK‐PZ, the factors responsible for their release may differ from those in other species. The present findings provide further evidence that the control of bile formation in rabbits and guinea pigs differs from that in other species, and it is possible that these differences could be related to the temporal pattern of their eating habits.
ARTERIAL BLOOD PRESSURE IN THE UNANAESTHETIZED FETAL LAMB AFTER CHANGES IN FETAL BLOOD VOLUME AND HAEMATOCRIT
Authors: Faber J. Job , Green Thomas J. , Thornburg Kent L.
Published: December 2014

Fourteen sheep fetuses in the third trimester of gestation were surgically prepared with intravascular catheters and five were nephrectomized. All experiments were done on unanaesthetized fetuses in utero, 3 to 9 days after surgery. Mean arterial blood pressure was recorded while fetal blood volume was changed by injection or withdrawal of blood, or infusion of Ringer's or dextran solutions. Fetal arterial blood gases and pH changed little during the experiments and were shown not to have affected the results. Arterial blood pressure was strongly influenced by changes in fetal blood volume and was also found to depend on haematocrit. There were no detectable differences between the responses of normal and nephrectomized fetuses or between normal fetuses and fetuses treated with hexamethonium. In all preparations central venous pressure depended on blood volume. Heart rate did not depend on blood volume in normal fetuses, but an increase in heart rate with an increase in blood volume was seen after hexamethonium. The open loop gain of baroceptor control of arterial blood pressure could not be proved to differ significantly from zero. Venoconstrictor responses and heart rate responses of reflex origin did not occur when arterial blood pressure was changed. The absence of detectable baroceptor control appears to explain the great sensitivity of arterial blood pressure to blood volume in the unanaesthetized fetal lamb.
THE DIVISION OF CONTROL OF MUSCLE SPINDLES BETWEEN FUSIMOTOR AND MIXED SKELETOFUSIMOTOR FIBRES IN A RAT CAUDAL MUSCLE
Authors: Andrew B. L. , Part N. J.
Published: December 2014

The segmental caudal muscles of the rat, which contain two or three muscle spindles, usually have a single γ fibre. Fourteen γ fibres have been stimulated in isolation and produced a static effect during 3 Hz sinusoidal stretching of the muscle. There are usually two oi three slowly contracting (contraction time 36–56 msec) motor units in each muscle; one or two of the efferents to these in each muscle have been shown to be β dynamic fibres. Twenty four dynamic β fibres have been studied in isolation. Rapidly contracting motor units (contraction time 10–22 msec) have been examined but no dynamic β fibres innervating them have been detected. The efferent innervation of a typical caudal segmental muscle in the mid‐tail region has been shown to be 1 static γ, 1 dynamic β with slow intrafusal unit, 1 α fibre innervating a slow unit, and five to eight α fibres innervating fast units.
THE PHOSPHOLIPASE ACTIVITY OF SHEEP PANCREATIC JUICE
Authors: Arienti G. , Leat W. M. F. , Harrison F. A.
Published: December 2014

Sheep pancreatic juice was found to contain at least two enzymes which hydrolysed biliary lecithin. One enzyme was heat and acid labile and hydrolysed the fatty acid from position 1 (phospholipase A1); the other was heat and acid stable hydrolysing the fatty acid at position 2(phospholipase A2). Lysophospholipase activity was also present. The phospholipases were active at pH values greater than 4·2, and would therefore function in the acid conditions (pH 3–6) of the sheep small intestine. The activity of the pancreatic phospholipases, and A2 in particular, was dramatically stimulated by the presence of the secretions of Brunner's glands which could be important in accelerating the hydrolysis of biliary lecithin in the lumen of the intestine. Phospholipase A1 was sensitive to acid in the range pH 2·5—3·5 and could therefore be partially inactivated by abomasal digesta; but phospholipase A2 was resistent to acid treatment.
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.
LACTOFERRIN IN RABBIT BILE: ITS RELATION TO IRON METABOLISM
Authors: Van Vugt H. , Van Gool J. , Ladiges N. C. J. J. , Boers W.
Published: December 2014

The relation of biliary lactoferrin concentration and the iron status of the body was studied in normal, anaemic and iron‐loaded rabbits. In anaemic rabbits lactoferrin concentrations rose to two to three times the original values. Loading with iron resulted in a return to normal values. Mobilization of iron with desferrioxamine also gave a rise in lactoferrin concentration in bile. Lactoferrin may have a regulatory function in situations of enhanced iron absorption or mobilization of iron from depots.
THE ACUTE EFFECTS OF INTRAVENOUS INFUSION OF PARATHYROID HORMONE ON URINE, PLASMA AND SALIVA IN THE SHEEP
Authors: Clark R. C. , French T. J. , Beal A. M. , Cross R. B. , Budtz‐Olsen O. E.
Published: December 2014

Following an intravenous loading injection of 75 U.S.P. Units of Para‐Thor‐Mone (Eli Lilly and Co.), seven conscious, non‐pregnant, non‐lactating Merino ewes were infused with a maintenance dose of the hormone at a rate of 4·75 U.S.P. units/min for 2 hr. The classical hypercalcaemia and hypophosphataemia of the non‐ruminant was observed, but the hypercalcaemia was only small. Plasma potassium concentration decreased, while there were no changes in plasma sodium, chloride or magnesium. The classical phosphaturic effect of the hormone was not observed, only trace amounts of phosphate being excreted throughout the experiment. Urinary excretion of calcium and magnesium decreased, urine flow and urinary excretion of sodium, potassium, chloride, bicarbonate and urine pH increased. Glomerular filtration rate was unaffected, but renal plasma flow increased. The concentration and secretion rate of salivary phosphate increased markedly. Changes in the other important salivary electrolytes (sodium, potassium, chloride, bicarbonate and hydrogen ion) also occurred, but it was difficult to separate primary from secondary effects of the hormone. Saliva flow rate increased transiently following hormone injection, but the effect was not sustained by the maintenance infusion.
CHANGES IN RENAL HAEMODYNAMICS AND ELECTROLYTE EXCRETION DURING ACUTE HYPERKALAEMIA IN CONSCIOUS ADRENALECTOMIZED SHEEP
Authors: Beal A. M. , Budtz-Olsen O. E. , Clark R. C. , Cross R. B. , French T. J.
Published: December 2014

The p‐aminohippurate (PAH) clearance, inulin clearance and the excretion of electrolytes by 10 adrenalectomized sheep were measured before, during and after the infusion of 0·43 M‐KCl at 2 ml./min for 2 hr. The PAH clearance increased as the plasma potassium concentration increased up to approximately 6·0 m‐mole/l. Further increases in plasma potassium were associated with a progressive return of the PAH clearance to or below the pre‐infusion levels. At its maximum the PAH clearance was 1·228±0·032 (S.E. of mean) times the pre‐infusion levels. The inulin clearance increased to reach a maximum coincident with or subsequent to the maximum PAH clearance. The maximum level of inulin clearance during the hyperkalaemia was 1·158±0·020 times the pre‐infusion clearance. The increments in the clearance of potasium and of bicarbonate rose rapidly to exceed the increment in inulin clearance during the hyperkalaemia in all experiments. The increments in the clearance of sodium and of chloride exceeded the increment in inulin clearance in more than half the experiments. It was concluded that although hyperkalaemia was associated with increased glomerular filtration much of the increased excretion of sodium, chloride and bicarbonate was derived from depressed tubular reabsorption of the ions. When the infusion experiments were repeated on the same animals the sheep demonstrated an improved ability to control the rise in plasma potassium concentration which was similar to potassium adaptation described in other species. There were no apparent differences between sheep maintained on 1·5 mg and 5 mg deoxycorticosterone acetate daily in their adaptation to potassium loading and the effect was tentatively attributed to the level of steroid maintenance being chronically high. The toxicity of hyperkalaemia was not lessened by this adaptation to potassium loading.
THE COMPOSITION AND FLOW OF PAROTID SALIVA DURING ACUTE HYPERKALAEMIA IN SODIUM‐DEFICIENT SHEEP
Authors: Beal A. M. , Clark R. C. , Budtz‐Olsen O. E.
Published: December 2014

Sheep were infused intravenously with 0·43 M‐KCl at 2 ml/min for 2 hr while they were either sodium‐replete or sodium‐deficient after the unilateral loss of parotid saliva for 18 hr or 3 days. Salivary flow was depressed during potassium infusion and the flow rates observed at maximum hyperkalaemia were similar in all three states of sodium balance despite the large differences in flow rate before potassium infusion. The fall in salivary Na/K ratio during potassium administration was diphasic, the initial decline being slow and followed by a more rapid fall in the ratio. The duration of the initial period of slow decline in this ratio ranged from 75–105 min, 45–60 min, and about 15 min in the sodium‐replete, mildly sodium‐deficient and severely sodium‐deficient states respectively. The decline in salivary flow during sodium depletion was associated with decreasing salivary bicarbonate concentration and increasing salivary phosphate and hydrogen ion concentrations with the concentration of chloride showing no consistent trend. During acute hyperkalaemia the chloride and phosphate concentrations were negatively correlated with salivary flow, the bicarbonate concentration was positively correlated with flow and the hydrogen ion concentration was unaltered. The sodium concentration of the saliva showed a statistically significant correlation with flow only when the sheep were severely sodium‐deficient.
DIVERGENT CHANGES IN THE RATE OF DEVELOPMENT OF PRESSURE IN THE LEFT VENTRICLE AND IN THE PERFORMANCE OF THE HEART AS A PUMP
Authors: Kane Kathleen A. , Ungar A.
Published: December 2014

Dog hearts were prepared in situ so that heart rate (HR), left ventricular end diastolic pressure (LVEDP) and mean aortic pressure (MAP) could be controlled separately during computation of left ventricular dP/dt max and external stroke work (sw). Progressive increases in HR consistently raised dP/dt max over a wide range, and consistently lowered sw except at low rates. Progressive increases in LVEDP or MAP consistently raised both dP/dt max and sw. Infusion of noradrenaline consistently raised both dP/dt max and sw, except at very high HR when only dP/dt max was consistently raised. Our results lead us to question the validity of equating changes in pre‐ejection measurements with changes in performance of the heart as a pump under abnormal conditions and in the assessment of inotropic agents.
TAURINE TRANSPORT RATES BETWEEN PLASMA AND TISSUES IN ADULT AND 7‐DAY‐OLD MICE
Authors: Oja S. S. , Lehtinen I. , Lähdesmäki P.
Published: December 2014

Transport rates for taurine from plasma to liver, kidney, heart, spleen and femoral muscle were evaluated in adult and 7‐day‐old mice in vivo. The mice were injected with [35S]taurine and the specific radioactivity of taurine was determined in the above tissues at varying intervals from 10 min up to 48 hr after the injection. A multicompartment model was fitted to the data and the transport rates with their confidence limits were estimated using a digital computer. The tissue‐plasma exchange rate was generally faster in adult mice than in 7‐day‐old mice. The transport rates between the plasma and the brain or muscle were low, while taurine penetrated into the liver and kidneys very rapidly. There was no distinct correlation between the calculated transport rates and the tissue taurine concentrations. The metabolic breakdown of taurine in the tissues was slow, since only negligible amounts of radioactivity were recovered in the metabolites of taurine, isethionic acid and inorganic sulphate. It seems unlikely that either the magnitudes of the transport rates between the plasma and the tissues or taurine breakdown rates in situ act as the primary factor determining the taurine levels in tissues.
ROUTES OF CALCIUM MOVEMENT ACROSS THE CHICK CHORIOALLANTOIS
Authors: Crooks Jane R. , Kyrlakdes Christine P. M. , Simkiss K.
Published: December 2014

The mechanism of calcium transport across the chick chorioallantois has been studied in vivo. The 15 day old membrane contains no calcium binding protein (CaBP) and attempts to stimulate transport by adding this protein or vitamin D metabolites did not enhance the normal transport process. The mitochondrial and microsomal fractions of transporting cells contain only a small percentage of the 45Ca actually moved across the epithelium and simultaneous measurements of 45Ca and 3H inulin indicate that the bulk movement of fluid is not involved in calcium transport Calcium appears to be moved after being bound to a protein since strontium and PCMBS both interfere with transport and the membrane shows saturation kinetics. It is suggested that none of the existing theories provides an adequate explanation for the mechanism of calcium transport and some support is given to the possibility that intercellular routes are involved in part of the process.
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.
BODY TEMPERATURE REGULATION AND THERMONEUTRALITY IN RATS
Authors: Poole S. , Stephenson J. D.
Published: December 2014

Various concepts of thermoneutrality were considered for a proposed study of the role of hypothalamic amines in temperature regulation of rats. The classic definition, the ambient temperature over which metabolic rate is minimum and constant, gave a range of approximately 28 to 32°C. However, within this temperature range rats were inactive, the inactivity apparently representing a behavioural response to heat stress and itself responsible for the reduced metabolic rate; certain thermoregulatory effectors were also activated to increase heat loss. Therefore an alternative range, 18·0±1·9 (mean ± S.D.) to 28·1±1·°C, was defined in which rats displayed normal activity, behavioural thermoregulation being absent.
THE INFLUX OF ISOLEUCINE INTO THE CEREBRAL HEMISPHERES AND CEREBELLUM: CARRIER‐MEDIATED TRANSPORT AND DIFFUSION
Authors: Daniel P. M. , Pratt O. E. , Wilson Penelope A.
Published: December 2014

The influx of L‐isoleucine from the blood into the cerebral hemispheres, and into the cerebellum, of the living rat was studied. When various raised levels of L‐isoleucine were maintained in the circulation, influx did not increase in proportion to the raised blood levels, which showed that a carrier‐mediated transport was being saturated. It was found that the values for influx could not be explained precisely by Michaelis‐Menten kinetics. The divergence of the observed values for influx, from those which were obtained by the application of Michaelis‐Menten kinetics, could be explained if part of the influx was due to a small, non‐saturable component. This minor component of influx may be due to diffusion or to a second carrier‐mediated transport system that is not readily saturated.
INTESTINAL LYMPH FLOW AND LYMPHATIC TRANSPORT OF PROTEIN DURING FAT ABSORPTION
Authors: Turner S. G. , Barrowman J. A.
Published: December 2014

A substantial increase in intestinal lymph flow and protein content follows fat ingestion. The effect of intraduodenal feeding of fats was studied in the rat to define the mechanisms responsible. The change appears to be largely independent of the route of fat absorption, that is, whether by the portal venous route or, alternatively, by the lymphatic route. It must be presumed that it is related to events unconnected with the route taken by absorbed fat leaving the intestinal cell.
PHYSIOLOGICAL STUDIES ON FACIAL REFLEXES IN THE RAT
Authors: Martin Michael R. , Biscoe T. J.
Published: December 2014

Experiments were performed on 36 male albino rats anaesthetized with pentobarbitone sodium and paralyzed with gallamine triethiodide. Recordings were made with single and multibarrel glass microelectrodes in the facial nucleus and monopolar silver wire electrodes on the lingual, facial, glossopharyngeal and hypoglossal nerves. The absolute refractory period for facial motoneurones is 2–3 ms, the relative refractory period has a duration of 26–34 ms and the range in axonal conduction velocities is from 15 to 45 m.sec‐1. No evidence for afferent fibres in the muscle branches of the facial and hypoglossal nerves could be found. The lingual and glossopharyngeal nerves show reflex connexions with both the facial and hypoglossal nerves. The time courses of the potentiations and depressions of test facial antidromic field potentials following lingual and glossopharyngeal conditioning stimuli are given. Evoked synaptic activity and the distribution of field potentials in the facial nucleus following lingual and glossopharyngeal nerve stimulation are also described. The observed lingual and glossopharyngeal‐facial reflexes are discussed with respect to blink reflexes.