bluuebunny/crossref_metadata_2025 huggingface dataset:
SECRETORY AND STRUCTURAL EFFECTS OF 6‐HYDROXY‐DOPAMINE ON NORMAL PAROTID GLANDS OF RATS, AND AT DIFFERENT TIMES AFTER SURGICAL SYMPATHECTOMY
Authors: Thulin A. , Garrett J. R.
Published: December 2014

The effects of i.v. 6‐hydroxydopamine (6‐OHDA), 100 mg/kg, have been studied on parotid glands of rats at 12, 24, 48, 72 hr and 3 weeks after avulsion of the right superior cervical sympathetic ganglion. The salivary flow from normal left control glands and from right glands 12 hr after ganglionectomy were similar, but at longer times after ganglionectomy the secretory response from the test glands was greatly reduced.

Morphological assessment showed that 6‐OHDA induced a massive depletion of secretory granules from all control glands and also at 12 hr after ganglionectomy but at 48 and 72 hr there was considerably less depletion of granules on the ganglionectomized side.

It is thought that at the longer times after ganglionectomy the secretion from the test glands is caused by circulating catecholamines released by the action of 6‐OHDA on adrenergic nerves elsewhere, plus a possible small direct secretogogue effect of 6‐OHDA. The additional effects on the normal side and at 12 hr after ganglionectomy are thought to be attributable to the release of catecholamines from adrenergic nerves within the gland.
THE EFFECT OF CHOLESTEROL OLEATE TREATMENT OF MICE ON THE ROSETTE FORMING CELL RESPONSE AGAINST SHEEP ERYTHROCYTES
Authors: Smith I. I. , Dewar A. Edna , Ramage Elizabeth F. , Stuart A. E. , Adams W.
Published: December 2014

Mice injected with a single dose of 60 mg cholesterol oleate emulsion showed substantial blockade of the mononuclear phagocyte system, measured by the rate of vascular clearance of radio‐labelled sheep erythrocytes. The labelled erythrocytes, in lipid treated mice, localized mainly in the spleen, contrasting with control mice in which localization was mainly in the liver.

Treatment with this lipid, 24 hr before the intravenous injection of two different doses of sheep erythrocytes, resulted in significant depression of the rosette forming cell response in the spleen, whereas the responses in the lymph nodes of both control and lipid treated mice were at a low level and not significantly different. Intravenously administered cholesterol oleate emulsion is known to localize mainly in the Kupffer cells and in splenic red pulp macrophages. Cultured macrophages treated with this lipid show inhibition of antigen‐binding and depressed phagocytosis of heterologous erythrocytes. The lipid does not affect lymphocytes.

These findings are in keeping with the hypothesis that macrophages play a direct role in the induction of an immune response against a particulate antigen.
CHANGES IN URINARY WATER AND ELECTROLYTE EXCRETION IN SODIUM‐LOADED SHEEP IN RESPONSE TO INTRAVENOUS INFUSION OF ARGININE VASOPRESSIN
Authors: Scott D. , Morton J. J.
Published: December 2014

Mature sheep receiving supplements of sodium chloride into the rumen were given intravenous infusions of arginine vasopressin at rates varying from 4·6–23 pmol/min (2–10 mU/min). Infusion of the hormone led to an increase in urine flow and to increases in the amounts of sodium and chloride excreted, the effect on flow was, however, the greater so that the osmolality of the urine fell during the infusions.

In sheep given intravenous infusions of a hypertonic sodium chloride solution addition of vasopressin to the infusate led to the formation of a larger volume of urine containing a higher proportion of the infused salt load compared to when the salt solution alone was given. As before the effect on flow was the greater and hence the osmolality of the urine was lower when the hormone was given.

In other experiments intravenous infusion of a hypertonic sodium chloride solution at rates providing 2—8 mmol NaCl/min led to increases in urine flow and increases in sodium and chloride excretion, the size of these increases being proportional to infusion rate. Plasma vasopressin levels markedly increased during these infusions, the levels seen being similar to those seen in sheep given vasopressin in amounts which increased both urine flow and electrolyte excretion. This suggests that during hypertonic salt loading vasopressin probably contributes directly to the increases in urine flow and the increases in electrolyte excretion which are seen. Further evidence in support of this was obtained in experiments in which a greater natriuretic response was seen in sheep given a hypertonic sodium chloride solution into the carotid artery as opposed to the jugular vein and where it was shown that plasma vasopressin levels were indeed higher when the solution was given into the artery.
UNCHARTED CHOLINERGIC NERVES IN THE RABBIT PAROTID GLAND
Authors: Alm P. , Ekström J.
Published: December 2014

Cholinergic nerves are shown to be left in the rabbit parotid gland after avulsion of the auriculo‐temporal nerve: a cholinesterase inhibitor injected through the duct caused secretion, thereby revealing leakage of acetylcholine from cholinergic nerve endings, and acetylcholinesterase positive nerves were found histochemically. The incomplete cholinergic denervation offers an explanation to the fact that some choline acetyltransferase activity remains in the ‘denervated’ glands.
PROPERTIES OF THE CALCIUM‐ACTIVATED ADENOSINE TRIPHOSPHATASE FROM L‐CELL MEMBRANES
Authors: Lindsay R.
Published: December 2014

Preparation of surface membranes from mouse L‐cells using a technique previously described in the literature [Perdue & Sneider, 1970] allowed characterization of a Ca‐activated ATPase apparently separate from the mitochondrial ATPase also dependent on calcium. This enzyme is associated with the Na‐K‐ATPase, a marker for surface membranes, and not with alkaline phosphatase, a mitochondrial enzyme. In temperature sensitivity, pH dependence and inhibition by ethacrynic acid, the partially purified enzyme has properties similar to those previously described for active calcium efflux from these cells. For maximal activity of the enzyme system magnesium and sodium are required, although the calcium transport from whole cells was apparently independent of both. Adenosine triphosphate only was metabolized by the enzyme system, whereas CTP could be utilized for calcium transport from ‘ghost’ cells, probably as a result of intracellular conversion to ATP. It is suggested that the active calcium transport from cultured L‐cells is closely linked to the calcium dependent ATPase, and that the method of calcium extrusion is similar to that described for red blood cells.
RESPONSE OF THE REGIONAL LYMPHATIC SYSTEM OF THE SHEEP TO ACUTE STRESS AND ADRENALINE
Authors: Shannon A. D. , Quin J. W. , Jones M. A. S.
Published: December 2014

An acute pain stimulus resulted in elevated lymph flow and output of cells from the popliteal lymph node of the sheep in the first 15 min after the stress. Efferent lymph flow increased by an average of 93% above the mean resting flow and cell output rose by an average of 170% during this period, but by 30 min after the stress, values for both lymph flow and cell output had returned to normal. The cell content of the efferent lymph was significantly higher in the first 15 min after the acute stress and it is suggested that there is a sizeable pool of lymphocytes within the resting popliteal node which can be mobilized into the lymph by an acute stress. A single intravenous injection of 1 mg adrenaline increased the efferent lymph flow in all the sheep examined but gave rise to an increased cell output in only 50% of the sheep. This indicated that there may be other factors, possibly hormonal, involved in the movement of the pool of lymphocytes out of the regional lymph node following acute stress.

Both acute pain stress and adrenaline resulted in an increased afferent popliteal lymph flow and output of cells from the regional tissues in the first 15 min after administration. The results are suggestive of a small pool of lymphocytes in the regional tissues which may be readily mobilized by either acute stress or adrenaline.

Part of the increases in efferent and afferent lymph flow observed following acute stress and adrenaline appeared to be due to an increased lymph formation, presumably as a result of an increased capillary pressure. Nevertheless, it is considered that the greater part of the increased flow of lymph from both regions resulted from an accelerated movement of performed lymph.
CHANGES IN ARTERIAL BLOOD PRESSURE, HEART RATE AND HAEMATOCRIT DURING ACUTE HYPERKALAEMIA IN CONSCIOUS SHEEP
Authors: Beal A. M.
Published: December 2014

The systolic, diastolic and mean arterial blood pressures, heart rate and haematocrit were measured at 15 minute intervals before, during and after 2 hour infusions of 0·4 mol.l‐1 NaCl at 2·2 ml min‐1 into conscious intact sheep and of 0·4 mol.l‐1 KCI at 2·2 ml. min‐1 into conscious sheep which were either intact or adrenalectomized. The haematocrit was also measured in splenectomized sheep receiving 0·4 mol.l‐1 KCI. The NaCl infusion had no significant effect on blood pressure (BP), heart rate and haematocrit. Both intact and adrenalectomized sheep were able to withstand an increase in plasma potassium concentration in excess of 50% of the preinfusion concentration before any substantial fall in BP occurred. In intact and adrenalectomized sheep, heart rate and haematocrit increased rapidly and progressively throughout the potassium infusions and at maximum plasma potassium concentration the mean increments in these parameters for both groups of sheep were 21·6±2·69 beats/min and 7·5±0·47% respectively. Heart rate and haematocrit were more closely correlated with the plasma potassium concentration than with any other variable measured in these experiments. Adrenalectomy did not reduce the ability of the sheep to maintain their BP or to increase their heart rate and haematocrit. As the mean increase in haematocrit during potassium infusion into splenectomized sheep was 1·3±0·45% most of the increase in haematocrit observed in the potassium‐infused intact and adrenalectomized sheep was caused by ejection of red cells from the spleen into the circulation.
VARIATIONS IN THE DISTRIBUTION OF CALCIUM, MAGNESIUM AND INORGANIC PHOSPHORUS WITHIN CHRONICALLY CATHETERIZED SHEEP CONCEPTUSES DURING THE LAST EIGHT WEEKS OF PREGNANCY
Authors: Mellor D. J. , Matheson I. C.
Published: December 2014

The concentrations of calcium, magnesium and inorganic phosphorus were higher in foetal arterial plasma than in maternal jugular plasma in sheep examined between 90 and 145 days of gestation. During the same period the calcium and magnesium concentrations of foetal urine were usually less than amniotic fliud values which in turn were less than maternal plasma concentrations. In allantoic fluid, calcium concentrations were usually less and magnesium concentrations greater than maternal and foetal plasma values. A 2—5 fold increase in the calcium concentrations of allantoic fluid after superficial uterine surgery and in amniotic fluid from a group of foetuses that were exposed during operation, were considered to be artefacts of technique. Inorganic phosphorus concentrations in foetal urine, amniotic fluid and allantoic fluid were variable.
THE EFFECTS OF VASOPRESSIN ON RENAL SODIUM EXCRETION IN PIGS GIVEN INTRAVASCULAR HYPERTONIC SALT LOADS
Authors: Scott D. , Morton J. J.
Published: December 2014

Young pigs of about 25–30 kg liveweight were given intravenous infusions of a hypertonic sodium chloride solution (4·6 mol.l–1) at rates varying from 2–6 mmol. min–1. Such infusions resulted in a marked increase in urine flow and in urinary sodium excretion, the size of these increases being proportional to infusion rate. Circulating vasopressin levels were also markedly increased, the size of these increases being the same as those seen in other pigs given exogenous vasopressin in amounts which were shown to increase urinary sodium excretion. This suggests that vasopressin was probably contributing to the increase in renal sodium excretion seen in those pigs given the intravenous salt loads.

Further evidence for this was obtained in experiments in which a greater natriuretic response was found to accompany infusion of a hypertonic salt solution into the carotid artery as opposed to the jugular vein and in which it was shown that circulating vasopressin levels were much higher when the solution was given into the artery. Furthermore, addition of exogenous vasopressin to a hypertonic sodium chloride solution greatly increased the amount of sodium excreted during an infusion compared with when the salt solution alone was given.
THE REPEATABILITY OF THE MEASUREMENT OF AEROBIC POWER IN MAN AND FACTORS AFFECTING IT
Authors: Thompson J.
Published: December 2014

The repeatability of measuring man's aerobic power was tested with regard to the influences from the following; 1. The immediate repeatability of the test. 2. The time sequences in which the progressive load increments are applied. 3. The subject's personal activities in the eighteen hours prior to the test. 4. The temperature of the laboratory during the test. 5. The time of day at which the test is carried out. 6. The day of the week on which the test is carried out. 7. The nervous state of the subject during the test produced by drugs affecting the autonomic nervous system. It was considered that aerobic power can be consistently measured in man as a standard control measurement if the following criteria are taken into account. The subject should be tested: 1. during the first few hours of his working day, 2. in an ambient temperature of not more than 4°C above that of his normal working environment, 3. when he has been normally active during the previous 24 h, 4. when he is systematically free from drugs, particularly those affecting the nervous system, 5. when free from a previous severe stress, 6. at least 1 h after a cigarette or contact with a smoke aerosol.
THE STIMULATION OF SHEEP MONOCYTE MITOSIS IN VITRO BY AUTOLOGOUS PLASMA TAKEN AFTER SURGERY AND THE IMPLANTATION OF FOREIGN MATERIAL
Authors: Greenwood B.
Published: December 2014

When blood monocytes from sheep are grown upon glass in 100% autologous plasma they divide with low mitotic indices, but if the plasma is taken from the sheep three or four days after the implantation of a small Teflon or stainless steel cylinder, the maximum mitotic indices of the monocytes cultured in that plasma rise. Plasma collected from the sheep in the first two days after operation is often toxic to cultured autologous monocytes. An equivalent sham operation increases the mitogenicity of the plasma, but without a preceding toxic period. No consistent effects upon the numbers of circulating blood monocytes were noted following implantation operations. A hypothesis is presented which suggests that blood monocyte multiplication in vivo and in vitro is dependent upon (a) a lesion which causes cell attachment, and (b) a humoral component of the plasma which stimulates mitosis. Surgery, and the implantation of foreign materials will increase the concentration of such a substance in plasma.
EFFECTS OF CHRONIC HYDROCHLORIC AND LACTIC ACID ADMINISTRATIONS ON FOOD INTAKE, BLOOD ACID‐BASE BALANCE AND BONE COMPOSITION OF THE RAT
Authors: Upton P. K. , L'Estrange J. L.
Published: December 2014

In experiment 1, weanling rats were given, for 7 weeks, a commercial rat diet supplemented with hydrochloric acid at levels up to 560 mmol.kg‐1 dry matter. The supplement increased water intake but did not significantly affect food intake, live‐weight gain, blood haemoglobin and haematocrit values or acid‐base balance. In experiment 2, adult rats were given, for 9 weeks, a commercial rat diet supplemented with hydrochloric acid at levels up to 1250 mmol.kg‐1 dry matter. Food intake and liveweight gain were not affected by hydrochloric acid concentration up to 625 mmol but at 938 and 1250 mmol.kg‐1 they were considerably reduced and there was 100% mortality of the rats. In experiment 3, weanling rats were given, for 12 weeks, a commercial rat diet supplemented with hydrochloric or lactic acid each at 300, 600 and 900 mmol.kg‐1 dry matter. Lactic acid at the three levels and hydrochloric acid at the two lower levels did not affect food intake or liveweight gain and had only a slight effect on blood acid‐base balance. At a dietary concentration of 900 mmol.kg‐1 dry matter, hydrochloric acid decreased food intake, induced a mild degree of metabolic acidosis and resulted in 30% mortality of the rats. In the three experiments, the acid treatments did not directly affect the length or composition of the femur of the rats.
THE ABSORPTION OF PHENFORMIN AND ITS EFFECTS ON GLUCOSE AND WATER ABSORPTION IN ISOLATED PERFUSED RAT SMALL INTESTINE
Authors: Gardner M. L. G. , Langslow D. R.
Published: December 2014

The effects of phenformin on glucose and water absorption from isolated perfused rat small intestine were studied. Luminal phenformin inhibited glucose and water absorption progressively as its concentration was increased from 0·1–1·0 mg.ml‐1. At 0·5 mg phenformin ml‐1, inhibition increased with time of exposure to phenformin up to 15 min and thereafter remained constant. Arterial infusion of phenformin (1·0 mg.ml‐1) produced less inhibition of glucose and water absorption. The site of phenformin's action appeared to be intracellular.

Phenformin absorption from a luminal perfusate (0·5 mg.ml−1) was measured. Although it was rapidly absorbed (224 µg.cm intestine−1.h−1) from the lumen, less than 2 µg.cm−1.h−1 appeared at the serosal surface of the intestine. In subsequent phenformin‐free perfusion, only 25% of the absorbed phenformin was recovered in the luminal and serosal effluents.
POST‐PRANDIAL DRINKING BY DOGS
Authors: Golob P. , O'Connor W. J. , Potts D. J.
Published: December 2014

When dogs were kept in metabolism cages with each drink recorded, drinking occurred after the single daily meal when the dogs were quiet in their cages. The drinking in the 10 hours after the meal is termed ‘post‐prandial’ and together with the water contained in the food forms the post‐prandial intake of water. Post‐prandial drinking, and water intake, were approximately doubled when the animal ate meals in which all items were doubled. Adding carbohydrate to the meal as dry biscuit or glucose caused post‐prandial drinking to increase by approximately 1 ml per g of added carbohydrate. Adding fat to the meal in the form of suet, had no significant effect on post‐prandial drinking. Meat added to the meal had no significant effect on post‐prandial drinking but the water intake was increased by the water in the meat. Since the water in the meat did not decrease drinking, as when water is given by stomach tube, it is concluded that protein and other solids of the meat provided a stimulus for the intake of 3·7 g water per g of protein. Post‐prandial water intake was apparently determined solely by the amount of carbohydrate and protein in the meal. The intermediary metabolism of both carbohydrate and protein, but not fat, requires water. Deposition of carbohydrate or protein in the tissues requires water; water accompanies the urinary excretion of urea produced by deamination of protein. These requirements were approximately matched by the observed post‐prandial water intake.
THE ENERGY COST OF LOCOMOTION ON THE LEVEL AND ON GRADIENTS FOR THE RED DEER (CERVUS ELAPHUS)
Authors: Brockway J. M. , Gessaman J. A.
Published: December 2014

The oxygen consumption (Vo2) of three castrated male red deer was measured while they walked on a treadmill at 7° and 14° slopes and on the level at speeds varying from 44·3 to 172·9 m.min‐1. The energy cost of horizontal locomotion in excess of standing was 2·6 J kg‐1.m‐1. The cost of maintenance of posture when walking was the same as that of standing. The energy cost of walking up gradients was 21·5 J kg‐1.vertical m‐1. These results are discussed in relation to values reported for other species.
POST PRANDIAL CHANGES IN PAROTID SALIVARY SECRETION AND PLASMA OSMOLALITY AND THE EFFECTS OF INTRAVENOUS INFUSIONS OF SALINE SOLUTIONS
Authors: Carr D. H. , Titchen D. A.
Published: December 2014

Parotid salivary secretion, reticular (gastric) contractions and blood osmolality were examined in conscious sheep prepared with re‐entrant parotid duct cannulae and given 1000 g of lucerne chaff daily. Osmolality of blood (portal, carotid and jugular) rose by 2–4 mosmoles. kg‐1 within 5 min of fresh food being given, continued to rise (up to 12–30 mosmoles. kg‐1) over the next 3 h and remained above levels detected before fresh food was given for up to 10 h. The greatest changes were in portal blood which was characteristically hyperosmolal to jugular and carotid blood; a difference which disappeared on fasting for 36 h. Parotid saliva which was 5–20 mosmoles. kg‐1 hyposmolal to jugular blood, increased to up to 6 ml. min—1 within 30 sec of the sheep starting to eat and although they continued to do so for some hours remained at these high levels for only about 30 min.

Attempts were made to see whether parotid salivary secretion was affected by changing the osmolality of the blood. Reductions in the rate of parotid salivary secretions and sometimes in the rate of reticular contractions were produced in conscious, anaesthetized and decerebrate preparations by making intravenous infusions of hyperosmolal solutions. The effects were stronger, and the latency shorter, when the infusions were made into the portal vein than when made into the posterior vena cava or a jugular vein. They were reduced by vagotomy and splanchnotomy although not abolished by both.

Increases in parotid salivary secretion and frequently, but not invariably, in the rate of reticular contractions followed intravenous infusions of isosmolal and hyposmolal solutions. In 6 experiments (of a total of 12) increases in parotid salivary secretion followed the intravenous injection of arginine vasopressin (0·06 mU.kg‐1), in none was saliva reduced by antidiuretic hormone.

The possible involvement of peripheral osmoreceptors in the inhibitory effects, and of receptors sensitive to changes in blood volume in the excitatory effects, is raised in relation to post‐prandial changes which occur in blood composition.
THE EFFECTS OF UREA INFUSION ON GLOMERULAR FILTRATION RATE AND RENAL PLASMA FLOW IN SHEEP FED LOW AND HIGH PROTEIN DIETS
Authors: Ergene N. , Pickering E. C.
Published: December 2014

Reducing the dietary N intake of sheep resulted in a significant fall in GFR with no change in RPF. Intravenous infusion of urea for 19—46 h had no effect on the high protein diet but on the low protein diet GFR and FF were increased to values approaching those observed on the high protein diet. On the low protein diet GFR was unaffected by infusion of urea for 4 h or of saline alone for 30 h. It is suggested that the observed changes in GFR are associated with changes in the quantity of protein passing to the abomasum and small intestine.
EFFECT OF HIGH FLUORIDE INTAKE ON HAEMATOLOGICAL ASPECTS OF THE MOUSE
Authors: Mehdi A. W. R. , Ridha M. T. , Al-Kafawi A. A. , Injidi M. H.
Published: December 2014

The effect of feeding adult Swiss albino mice of both sexes a diet supplemented with O, 125, 250 and 500 parts/106 of fluoride for four and eight week periods on haemoglobin concentration (Hb), packed cell volume (PCV) and mean corpuscular haemoglobin concentration (MCHC) was investigated. Values of the three parameters were significantly lowered at both periods in the treated groups as compared with the controls. The extent of reduction in these values was, in general, dependent on the dose of supplemented dietary fluoride. Clinical symptoms were not observed before the end of the sixth week. However, appearance of the symptoms did not change the trend of variations in Hb, PCV and MCHC values. The reduced values could be the result of lowered haemoglobin synthesis and erythropoiesis. It was suggested that these haematological indices could serve to detect preclinical effects of high fluoride intake with an added dose of as low as 125 parts/106, or even less, for a period of four weeks or probably earlier.
EFFECT OF SUB‐DIAPHRAGMATIC VAGOTOMY ON GASTRIC MUCOSAL MAST CELL POPULATION IN PYLORUS LIGATED RATS
Authors: Ganguly A. K. , Sathiamoorthy S. S. , Bhatnagar O. P.
Published: December 2014

Gastric mucosal mast cell population was studied following sub‐diaphragmatic vagotomy in albino rats, 6 and 12 h after pylorus ligation. Sub‐diaphragmatic vagotomy significantly increased the gastric mucosal mast cell population in both 6 and 12 h groups, the increase being more in the latter. The results suggest that the vagal impulses act on the gastric mucosal mast cells causing their degranulation. Following vagotomy the contents stay bound within the mast cells. Increase in mast cell population with the longer experimental situation was possibly due to the continuation of normal turnover of the mast cells in the gastric mucosa. The present study, however, does not lead to a conclusion that the vagal influence on mast cell population is similar throughout the gastro‐intestinal tract.
THE EFFECTS OF INTRAVENOUS PHOSPHATE LOADING ON SALIVARY PHOSPHATE SECRETION AND PLASMA PARATHYROID HORMONE LEVELS IN THE SHEEP
Authors: Scott D. , Beastall G.
Published: December 2014

Adult sheep were given intravenous infusions of a solution of Na2HPO4 and the effects on parotid salivary composition and on plasma parathyroid hormone levels were studied. Infusion of the phosphate solution resulted in increases in the concentration of inorganic phosphate in the plasma and to proportional increases in the concentration and amount of phosphate secreted in the saliva. There was, however, no evidence that the salivary response was dependent upon a change in endogenous parathyroid hormone release. In other studies infusion of bovine parathyroid hormone or stimulation of endogenous hormone release through infusion of EDTA both led to a fall in the concentration of inorganic phosphate in the plasma and to a fall in the concentration and amount of phosphate secreted in the saliva. Taken together these results suggest that the major factor affecting salivary phosphate secretion in these studies was the concentration of inorganic phosphate in the plasma. Parathyroid hormone does not appear to have any direct effect on salivary phosphate secretion in the sheep though it may indirectly influence phosphate secretion through its effects on plasma inorganic phosphate level.
MECHANISM OF HYPOTHALAMIC CONTROL OF CARDIAC COMPONENT OF SINUS NERVE REFLEX
Authors: Lopes O. U. , Palmer J. F.
Published: December 2014

The modulatory influence of hypothalamic structures on sinus nerve induced bradycardia was investigated in anaesthetized cats. Stimulation of the hypothalamic defence area inhibits the bradycardia produced by sinus nerve stimulation both in intact animals and also in animals with the spinal cord sectioned at C1 or C6. This inhibition was accompanied in the normal animal by an increased sympathetic discharge and by a sustained inspiration or tachypnoea. The same respiratory effects were noted in a spontaneously breathing C6 spinal animal, while an artificially ventilated C1 spinal animal still displayed a powerful central inspiratory drive in its recurrent laryngeal electroneurogram. The presence of central inspiratory activity was found to be an absolute impediment to the development of bradycardia. If this activity was eliminated by simultaneous stimulation of the superior laryngeal nerve, it was possible to obtain bradycardia during combined sinus nerve and hypothalamic defence area stimulation, though this bradycardia was modified by the presence of sympathetic discharge. The level of sympathetic neural discharge affects the magnitude of the bradycardia produced by sinus nerve stimulation. The bradycardia was less with a normal or augmented level of sympathetic activity and was greater if this activity was reduced or absent. A lesion just caudal to the mammillary bodies disclosed a tonic hypothalamic influence both on respiration and on sympathetic discharge; stimulation of the sinus nerve produced a much more powerful bradycardia after the lesion. The existence of a respiratory ‘gate’ through which afferent stimuli pass on their way to the nucleus ambiguus, and which can be operated by the hypothalamic defence and depressor areas, is postulated and discussed.
CARDIAC OUTPUT DURING SUBMAXIMAL EXERCISE IN NEW GUINEANS: THE RELATION WITH BODY SIZE AND HABITAT
Authors: Patrick J. M. , Cotes J. E.
Published: December 2014

Cardiac performance in moderate bicycle exercise has been measured in five groups of New Guineans (N = 161). Men and women in both coastal and highland (2000 m) locations were studied, as well as a group of highland men after migration to the coast. The results have all been standardized to an oxygen consumption of 1 l.min−1.

Cardiac output values are similar to those previously quoted for Europeans; a significant positive correlation with body size is found, and resident highlanders appear to have slightly larger cardiac outputs (+4%) and larger stroke volumes (+10%) after adjustment for body size, but this is not because they have larger hearts. The highland migrants at sea‐level share none of the ‘altitude’ characteristics of the highland residents and, after size‐adjustment, correspond with the lowlanders. The cardiac frequencies of the lowland women are higher than the other groups (+15 beats. min−1) after adjustment for differences in body size. Their values are close to those found previously for moderately active Europeans, while all the other New Guinean subjects have lower cardiac frequencies probably because of their greater habitual activity.
THE EFFECTS OF CHANGES OF THE TONICITY OF THE BATHING FLUID UPON THE TENSION GENERATED BY ATRIAL TRABECULAE ISOLATED FROM THE HEART OF THE FROG, RANA PIPIENS
Authors: Chapman R. A.
Published: December 2014

Raising the tonicity of the fluid bathing frog atrial trabeculae has three effects: an initial sustained relaxation, which depends on muscle length and probably originates from structures other than the contractile apparatus; an increase in contractility, which takes the form of a transient contracture if the muscle has previously undergone a high‐potassium or a low‐sodium contracture, and a further rise in contractility on return to isotonic fluid (off response). The hypertonic contractures, in high‐potassium or sodium‐free fluids, are antagonized by local anaesthetics and in Na‐free media they are unaffected by removal of extracellular Ca2+, whereas the ‘off responses’ are insensitive to both experimental manoeuvres. Hypotonic fluids applied in Na‐free solutions evoke a phasic and a tonic contracture, neither of which are sensitive to local anaesthetics. The tonic response is reduced by lowering the [Ca]o, and occurs at tonicities where the permeability of the cell membrane is likely to have increased. The phasic part of the hypotonic contracture resembles the ‘off response’ which follows exposure to hypertonic solution. The effects of hypertonic fluids and of caffeine on frog heart are alike, and are also similar to the responses induced by the same experimental manoeuvres in skeletal muscle. The results can be interpreted by assuming that the intracellular relaxing system in frog heart is sensitive to changes in tonicity, and could be functionally divided.
THE EFFECTS OF ANTIDIURETIC HORMONE ON URINE FLOW AND COMPOSITION IN THE CHRONICALLY‐CANNULATED OVINE FETUS
Authors: Lingwood Barbara , Hardy K. J. , Horacek I. , McPhee M. L. , Scoggins B. A. , Wintour E. Marelyn
Published: December 2014

The fetuses of nine pregnant ewes were chronically cannulated between 86 and 130 days with cannulae in one carotid artery, one jugular vein, the fetal bladder and the amniotic cavity. The effects of infused AVP on fetal urine flow rate and composition were studied. A dose of 35 pmol.h‐1 always caused an increase in urine osmolality and a decrease in flow rate and free water clearance without change in blood pressure. Higher doses (140 pmol. h‐1) were significantly pressor and caused increased excretion of sodium, chloride, urea and creatinine. Although this dose always caused an increase in urine osmolality, in five experiments the flow rate also rose. It is concluded that the ovine fetus has the ability to control its own urine flow and composition, and possibly also amniotic fluid volume and composition.
THE EFFECT OF INTRAVENOUS HYPERTONIC SALINE INFUSION ON RENAL FUNCTION AND VASOPRESSIN EXCRETION IN SHEEP
Authors: Yesberg Nancy E. , Henderson Myrna , Budtz‐Olsen O. E.
Published: December 2014

Conscious Merino ewes were given an intravenous hypertonic sodium chloride load of 4 mmol. min−1 for 100 min. This resulted in increases in urine flow, sodium and potassium excretion and plasma sodium concentration and osmolality. Urinary vasopressin output and solute‐free water reabsorption increased and plasma renin activity declined. Renal plasma flow and glomerular filtration rate (GFR) rose, as did the solute clearance. The change in urinary osmolality was related to the initial urine osmolality such that when the initial urine osmolality was high the urine became more dilute, and vice versa. Tubular sodium reabsorption increased but the fractional reabsorption rate fell.

It is suggested that the increase in GFR was at least partly due to the increase in AVP and that the electrolyte loss can be accounted for by the increase in GFR without necessarily involving AVP or other hormonal effects at the tubular level.
PORTAL CIRCULATIONS AND THEIR RELATION TO COUNTERCURRENT SYSTEMS
Authors: Henderson J. R. , Daniel P. M.
Published: December 2014

We have reviewed the distribution of portal circulations throughout the animal body; they are commoner than is generally supposed. Most portal circulations consist of two serial capillary beds connected by one or more larger vessels. We have called these ‘convergent’ portal circulations: examples are hepatic portal, placental, hypophysial, renal, ovarian and testicular circulations, as are parts of the lymphatic circulation. A second type of portal circulation, which is less common, consists of two serial capillary beds that are not connected by larger vessels. These we have called ‘continuous’ portal circulations: adrenal and pancreatic circulations are examples of this type.

When a countercurrent concentrating mechanism exists in the body it is always part of the primary or secondary bed of a convergent portal circulation, though some convergent portal circulations are not associated with countercurrent mechanisms.
SERUM ENZYME LEVELS DURING EXPERIMENTAL HYPOTHERMIA IN MAN
Authors: Marcus P. , Edwards R.
Published: December 2014

Deep surgical and accidental hypothermia cause elevations in serum enzyme levels, probably because of ultrastructural cell damage. Many variables hinder work on this problem in the clinical situation and the mechanism is obscure. Accordingly, enzymes and other physiological parameters were monitored in four subjects cooled four times, under controlled conditions in the labotarory, to a mean auditory canal temperature of 35·0°C. Mild hypovolaemia and acidosis occurred.

Serum enzyme levels did not change significantly and it is concluded that elevations due to hypothermia cannot be studied in laboratory experiments on heathly volunteers who can only safely be cooled to 35°C.
Vagus Nerves and the Gastric Tissue Histamine Concentration in Pylorus Ligated Albino Rats
Authors: Ganguly A. K. , Gopinath P.
Published: December 2014

Gastric tissue histamine concentration was determined, 6 and 16 hours after pylorus ligation in vagus intact and vagotomized albino rats and the results were compared with those of respective control animals, sacrificed, 6 and 16 hours after ether anaesthesia alone. The gastric tissue histamine concentration of rats subjected to none of the experimental situations was also determined and taken into comparison.

The results show that the stress of pylorus ligation reduced the gastric tissue histamine concentration, the reduction being more with increased duration of stress. On the other hand, subdiaphragmatic vagotomy preserved the histamine concentration of gastric tissue irrespective of the duration to which the animals were exposed following pylorus ligation. It appears that increase in vagal discharges during stress leads to increased liberation of histamine from the gastric wall, thereby, reducing the gastric tissue histamine concentration; the reduction being proportional to the duration of stress and increase in vagal discharges, whereas, in the absence of vagal impulses following subdiaphragmatic vagotomy, the gastric tissue histamine concentration is preserved in spite of the stress to which the animals were exposed.
Effect of Hyperammonaemia on Blood Glucose and Plasma Insulin Levels in Sheep
Authors: Barej W. , Harmeyer J.
Published: December 2014

The effects of continuous intravenous infusions (6 h) of ammonium chloride (5·6; 11·2; and 16·8 µmol.kg‐1) on plasma glucose and immunoreactive insulin (I.R.I.) levels were studied in three adult sheep. Infusions of 5·6 and 11·2 µmol.kg‐1.min elevated ammonia levels in circulating blood from 100 to 150 and 300, µg. 100ml‐1, respectively, but showed no appreciable effect on plasma glucose and I.R.I. concentrations. Infusion of 16·8 µmol kg‐1.min‐1 resulted in a blood ammonia concentration of about 400 µg.100ml‐1 after six hours of infusion. Blood ammonia returned to normal 1 to 2 hours after the end of infusion. Plasma glucose concentration tended to increase slightly from 65 to 75 mg. 100ml‐1 when 16·8 µmol of NH4Cl were infused kg‐1.min‐1 and remained at the elevated level at least for two additional hours when ammonia infusions were stopped. Plasma I.R.I. tended to decrease from 48 to 38 µU.ml‐1 during the time of the NH4Cl infusion and increased continually to 82µU.ml‐1 when NH4Cl infusions were stopped. It is concluded from the time courses of plasma glucose and plasma I.R.I. that the effect of ammonia infusion on these parameters cannot entirely be explained by a regulatory release of adrenaline.
Parasympathetic Degeneration Secretion of Saliva in Rats
Authors: Delfs Ursula , Emmelin N.
Published: December 2014

In rats under chloralose anaesthesia saliva was found to flow from the submandibular and parotid glands previously subjected to (partial) postganglionic parasympathetic denervation. Secretion started in the submandibular glands 8·8–11·8 hours, and in the parotid glands 14·0–21·6 hours after the denervation and lasted about 7 hours in both glands. It was not abolished by sympatholytic drugs but by atropine. It is regarded as an example of the “degeneration activity” described in many organs and species and provides a method for prolonged stimulation of salivary glands in rats.
The Relation Between Structure and Function of Bile Ducts in Man, Some Laboratory Animals and the Adelie Penguin
Authors: Andrews C. J. H. , Andrews W. H. H.
Published: December 2014

The biliary trees of man, dog, cat, rabbit, rat, guinea pig and penguin were examined in histological sections and by latex casts. The trees of man, dog and cat were similar with only minor differences. Tubulo‐alveolar glands were present in all three species around large intrahepatic ducts and in large portal tracts there were zones of ductules (areas with many small bile ducts), surrounded by small vessels with no apparent relation to hepatocytes. Both these features were present in the guinea pig and tubulo‐alveolar glands were present in the penguin liver. The biliary epithelium of the rat was comparatively simple but that of the rabbit appeared to be highly specialized. An estimation of the complexity of the biliary tree was obtained in the mammals by comparing the circumference of small portal venous branches with the circumference of the accompanying bile ducts, and obtaining a ratio. Man, dog and cat had fewer and smaller bile ducts than the other species. The literature on the rate of formation and composition of bile in the species studied here was reviewed and it appears that the physiology of bile secretion can be related to the morphology of the biliary tree.
Effect of the Canadian Air Force Training Programme on a Submaximal Exercise Test
Authors: Kappagoda C. T. , Linden R. J. , Newell J. P.
Published: December 2014

Validation of the submaximal heart rate/oxygen consumption relationship as an index of ‘cardiorespiratory fitness’ requires the demonstration of systematic alterations in this relationship concomitant with interventions designed to alter physical fitness. To fulfil those criteria a longitudinal training/de‐training study was undertaken. Previously sedentary adult subjects undertook the Canadian Airforce 5BX–XBX exercise programme. Submaximal exercise tests were performed before and after training, and following several weeks cessation of training. A regression line of submaximal heart rate on submaximal oxygen consumption was calculated from the data of each submaximal exercise test. Alterations in the regression lines were examined for each subject individually by testing statistically for difference in slope and elevation between any pair of lines. Subjects who undertook the training/de‐training study demonstrated significant systematic alterations in the elevation of the regression lines concomitant with periods of training and de‐training. The reproducibility of the submaximal heart rate/oxygen consumption relationship was examined in two additional groups of subjects. Group A repeated a submaximal test on 3 or 4 successive days; Group B were tested before and after 16 weeks of normal activity. Subjects in Group A demonstrated non significant, random alterations in the regression lines on repeated testing and subjects in Group B demonstrated random, though on occasion significant, alterations in the regression lines. The elevation of the submaximal heart rate/oxygen consumption relationship is therefore a valid index for detecting sequential changes in ‘cardiorespiratory fitness’ in individual subjects.
A Comparison of the Oxygen Consumption/Body Weight Relationship Obtained During Submaximal Exercise on a Bicycle Ergometer and on a Treadmill
Authors: Kappagoda C. T. , Linden R. J. , Newell J. P.
Published: December 2014

It is widely accepted that the relationship between oxygen consumption and body weight obtained during exercise on a bicycle ergometer differs from that obtained during treadmill walking. Experimental evidence to support this claim is lacking. To examine this difference a group of subjects (body weight 41—81 kg) undertook a predetermined level of submaximal exercise on a bicycle ergometer and on a treadmill. Oxygen consumption was measured in a steady state at rest (i.e. sitting on the bicycle ergometer and standing on the treadmill) and during the two modes of exercise. A significant positive correlation between oxygen consumption and body weight was obtained under all four conditions of measurement. At rest the two regression lines did not differ in slope or elevation. During exercise the slope and the elevation of the line obtained from treadmill walking were significantly greater than from bicycle ergometer exercise. The ‘metabolic cost’ of bicycle ergometer exercise, (Vo2 during exercise—Vo2 at rest), showed no significant correlation with body weight. In contrast, there was a significant positive correlation during walking. It is suggested that these differences have arisen due to a different proportion of the total body weight supported by the subject in the two forms of exercise.
Repetitive Responses in Squid Giant Axons and Their Premature Annihilation by Additional Brief Depolarizing Currents
Authors: Chapman R. A.
Published: December 2014

The repetitive responses induced in squid giant axons by the application of sustained depolarizing currents under space clamp conditions are described. The relationships between membrane current, and a number of features of the repetitive response of the living axon are compared to computations made for the Hodgkin‐Huxley equations. The comparison suggests that these equations adequately predict the form of the repetitive response, even so far as the ability of a brief additional depolarization to cause a premature end to the repetitive response.
An Analysis of the Choleretic Effects of Infusions of Sodium Cholate in the Guinea‐pig
Authors: Rutishauser Sigrid C. B.
Published: December 2014

The choleretic effects of infusions of sodium cholate, with and without the simultaneous infusion of taurine was compared with the choleretic effect of infusions of sodium taurocholate at rates ranging from 20–70 nmole/min. g. liver in anaesthetized guinea‐pigs. Sodium cholate was secreted in bile mainly conjugated with taurine and with glycine. 10% was secreted unconjugated. Not more than 10% of the total bile salts secreted may have undergone reduction at C‐3. The increase in bile flow with sodium cholate was generally greater than that with sodium taurocholate. The additional flow could not be correlated with the presence of glycocholate or free cholate in bile, and may be due to an action of cholate on biliary secretory mechanisms before the bile salt is secreted into the canaliculi.
A New Technique for Maintaining and Monitoring Conscious, Stress‐free Rabbits in a Steady State: Its Use in the Determination of Glucose Kinetics
Authors: Atkins Gordon L.
Published: December 2014

1. A new technique is described for maintaining and monitoring conscious rabbits in a steady state. Solutions were infused and blood samples were withdrawn without major surgery and without causing stress. Cannulation, for infusion and blood sampling, was via the ear veins and arteries.

2. The validity of the technique is discussed with special reference to: the amount of blood removed from the animal; the use of a plasma substitute solution; the use of heparin; and assessing whether the animal was in a steady‐state with respect to glucose.

3. The technique was used to determine glucose kinetics in the fasted rabbit after an injection of [2–3H] glucose with subsequent blood sampling over 2 h. A two compartment model was used to calculate certain physiological values, the two principal ones being the glucose uptake rate (3·30±0·24 (13) mg.kg–1. min–1) and the initial volume of distribution (74·8±7·8 (13) ml.kg–1).

4. The accuracy and precision of the results obtained from this study are discussed and shown to be more reliable than other published values.
Active Intestinal Transport of Methyl Red Isomers
Authors: Fisher R. B.
Published: December 2014

Transport across the wall of rat jejunum of two isomers of methyl red has been studied. These isomers, meta‐methyl red (MMR) and para‐methyl red (PMR), are absorbed against a concentration gradient. Uptake consists of three components: rapid adsorption on to the mucosa, a steady uptake proportional to lumen concentration and a reflux which increases exponentially to a limiting value. A substantial part of the uptake is stored in the mucosa, and some of it is metabolized to colourless derivatives. If methyl red is washed out of the lumen after the mucosa has been loaded, there is some reflux into the lumen, but most of the stored methyl red passes into the secretion. The rate of this transport on to the serosal surface is not noticeably diminished until the adverse concentration gradient exceeds 13–14:1. Once the methyl red has been washed out of the lumen there is no further metabolism of methyl red to colourless derivatives. Shifting the lumen pH from 7·4 to 6·4 whilst keeping the tissue fluid pH constant increases the rate of uptake from the lumen by a factor of only 1·68 although the concentration of unionized methyl red is increased approximately 10‐fold. It seems that at pH 7·4 about 90% of the uptake is of the ionized form, and that at pH 6·4 this percentage falls to 50. It is concluded that the methyl reds form fresh examples of foreign organic compounds which can be transported actively by the small intestine and that they can be taken up from the lumen into the mucosa in both ionized and unionized states.