bluuebunny/crossref_metadata_2025 huggingface dataset:
MODIFICATION OF DRUG-INDUCED HYPOTHERMIA
Authors: Lettau H. F. , Sellers E. A. , Schönbaum E.
Published: April 2011

Male albino rats, acclimated to 23 °C, were exposed to 2 °C and hypothermia was induced by means of reserpine, chlorpromazine, or noradrenaline. Pretreatment with imipramine, iproniazid, pargyline, or l-triiodothyronine of rats receiving reserpine resulted in better maintenance of metabolic rate and body temperature, and decreased mortality compared with animals receiving reserpine alone. In the case of chlorpromazine and noradrenaline the reverse occurred. Pretreatment with hydrocortisone reduced the hypothermic effect of reserpine, and to a lesser extent that of noradrenaline, but was ineffective with chlorpromazine.The findings are consistent with the hypothesis that noradrenaline is intimately involved with thermogenesis; when tissue stores are depleted, adrenotropic drugs exert a beneficial action but when large amounts of noradrenaline are injected or released endogenously the same drugs increase toxicity. It is suggested that pretreatment with hydrocortisone produces its beneficial effect by altering the pattern of metabolic pathways involved in heat production.
THE LIPOTROPIC ACTION OF COLD: 1. THE INFLUENCE OF COLD AND CHOLINE DEFICIENCY ON LIVER LIPIDS OF RATS AT DIFFERENT INTAKES OF DIETARY METHIONINE
Authors: Radomski M. W. , Wood J. D.
Published: April 2011

The effect of cold exposure and choline deficiency on the levels of liver lipids of male albino rats was studied at four dietary intakes of methionine (20–100 mg per rat per day). After exposure of the animals to cold (2–3 °C) for a 10-day period, the liver lipids were analyzed for total and free cholesterol, phospholipid, and triglyceride.In choline-fed animals, cold exposure did not affect triglyceride or total cholesterol levels but elevated phospholipid and free cholesterol and decreased ester cholesterol. The increase in phospholipid levels occurred at all methionine intakes with the changes in the cholesterol fractions occurring only at methionine intakes >40 mg per day.In choline-deficient rats, there was evidence that the lipotropic action of cold exposure was related to dietary methionine intake. At methionine intakes <60 mg per rat per day, fatty infiltration of the livers of the choline-deficient cold-exposed rats occurred, as evidenced by the accumulation of triglyceride and ester cholesterol. Concomitantly, phospholipid levels decreased. The data suggest that cold increases the capacity of the animal to synthesize choline from endogenous sources.
THE ROLE OF THE SEMICIRCULAR CANALS IN CAUSATION OF MOTION SICKNESS AND NYSTAGMUS IN THE DOG
Authors: Money K. E. , Friedberg J.
Published: April 2011

The discrete surgical inactivation of all six semicircular canals was found to be equivalent to bilateral labyrinthectomy in eliminating motion sickness in dogs, even though the otolith organs remained functional. Inactivation of fewer than six of the canals reduced the susceptibility of dogs to motion sickness, but to a lesser degree than did inactivation of all six canals. These findings are consistent with the theory that stimulation of the semicircular canals causes motion sickness.Rotatory tests of the horizontal and vertical semicircular canals and tests of an otolith reflex, preoperatively and postoperatively, yielded information about the basic functions of the semicircular canals and confirmed that the surgical procedures had accomplished their objectives without unintended damage to other vestibular receptors.
THE VASOCONSTRICTOR AND VASODILATOR EFFECTS OF PROCAINE
Authors: Sanders H. D.
Published: April 2011

Procaine hydrochloride (15 mg/kg) administered intravenously raises the systemic arterial pressure in spinal cats but lowers it in cats anaesthetized with pentobarbital. The rise in blood pressure is not due to release of adrenaline or noradrenaline since a pressor response to procaine still occurs after phenoxybenzamine. Procaine also increases the blood pressure in pentobarbital-anaesthetized cats after the administration of phenoxybenzamine or reserpine. The perfusion pressure in the isolated hind limb perfused at a constant flow was increased by procaine given intra-arterially in spinal cats. In contrast, procaine lowered the perfusion pressure in the hind limb of pentobarbital-anaesthetized cats. The results are consistent with a direct vasoconstrictor effect of procaine on peripheral vessels which is masked when sympathetic vasomotor tone is high. The fall in blood pressure after procaine in pentobarbital-anaesthetized cats may be due to an effect of the drug on terminal nerve endings.
THE INOTROPIC EFFECT OF l-NORADRENALINE IN EXPERIMENTAL CARDIOGENIC SHOCK
Authors: Cronin Robert F. P. , Tan Eng H.
Published: April 2011

The hemodynamic effects of noradrenaline infusion (1 μg/kg min) were studied in five normal dogs and in five dogs in whom cardiogenic shock had been produced by closed-chest coronary embolization.Noradrenaline infusion caused a significant increase in arterial blood pressure, cardiac output, and mean left-atrial pressure in all animals. In the shocked group, the observed increase in cardiac output was significantly less than in the control group.The inotropic effect of infused noradrenaline was quantitated in each animal by comparing the increase in left-ventricular stroke work evoked by noradrenaline with the increase in stroke work which occurred when the mean left-atrial pressure was elevated by autologous transfusion to the level previously attained during noradrenaline infusion. In the control animals, noradrenaline increased left-ventricular stroke work an average of 91% for an average increase in mean left-atrial pressure of 5.6 mm Hg while transfusion increased left-ventricular stroke work 72% for a similar rise in left-atrial pressure. In the shocked animals, noradrenaline increased left-ventricular stroke work 120% but transfusion increased it only 35% for a similar increase in mean left-atrial pressure.It is concluded that the inotropic effect of noradrenaline is enhanced in experimental cardiogenic shock.
INSULIN HYPERPHAGIA IN RATS FED A LOW-PROTEIN DIET
Authors: Beaton J. R. , Feleki V. , Stevenson J. A. F.
Published: April 2011

This investigation was undertaken to ascertain if daily treatment with insulin, known to increase lipogenesis, fat deposition, and food intake on a normal diet, could overcome or prevent, the hypophagia of rats fed a low-protein (5% casein) diet. Male Wistar rats on 20 or 5% casein diets were injected subcutaneously daily for 25 days with 2 units/100 g body weight of protamine zinc insulin (PZI) or saline. PZI increased the food intake and weight gain on both diets but not linear growth. It increased body fat markedly and protein slightly on the low-protein diet and body fat only on the normal diet. In a second similar experiment, in which treatment was continued for 17 days, PZI caused no change in resting oxygen consumption from that of the controls on either diet but did prevent the increase in running activity that rats on a low-protein diet show. In both experiments, although the insulin-treated rats on low-protein diet ate as many calories as the saline-treated controls on the normal diet, they gained significantly less weight. This paradox remains unexplained.The rebound increase in blood sugar following injection of PZI was relatively much faster in the low-protein animals. This was associated with a more immediate and greater food intake suggesting a "meal-eating" pattern of food intake in these animals which may have also enhanced lipogenesis.
THE ANTICOAGULANT ACTION OF POLYBRENE
Authors: Zipursky A. , Wodzicki A. M. , Russet J. I. , Israels E. D. , Israels L. G.
Published: April 2011

The anticoagulant action of the heparin antagonist Polybrene has been studied in vitro. Polybrene was found to interfere with the formation of intrinsic blood thromboplastin. On examination of the steps in the formation of thromboplastin, there was no interference with the production of the intermediate, product I. As this intermediate product is formed by the interaction of aluminium hydroxide adsorbed plasma, serum, and calcium, Polybrene does not appear to interfere with the interaction of factors VIII, IX, XI, or XII. It was noted, however, that the further reactions of product I with phospholipid were inhibited by this agent. It is suggested that the anticoagulant action of Polybrene is exerted at this point and is dependent on its capacity to neutralize the surface charge of the phospholipid particles.
THE RELATION BETWEEN ACUTE TOXICITY AND CRITICAL RATE OF DISPOSAL OF SEVERAL LOCAL ANESTHETICS
Authors: Cahill Joan F. , Aldous J. G. , Wenning A. S.
Published: April 2011

The maximum rate at which several local anesthetics may be administered intravenously and just fail to elicit clonic convulsions in unanesthetized rabbits has been compared to the acute LD50's reported in the literature. The exceptionally good agreement between the two sets of data suggests that the processes which remove active drug molecules from the blood operate equally well at high and low rates of administration.
INFLUENCE OF DIETARY FACTORS ON CERTAIN BLOOD PARAMETERS AND THE PRODUCTION OF ENDOTOXIN-INITIATED PHLEBOTHROMBOSIS IN RAT
Authors: Renaud S. , Allard C.
Published: April 2011

Provided rats were fed lipid-rich low-protein diets containing sodium cholate, a high incidence of large hepatic vein thrombosis could be initiated by the injection of E. coli or S. typhosa lipopolysaccharides. Although hyperlipemia seemed to be a necessary prerequisite for the induction of these phlebothromboses, no definite relationship could be found between the tendency to thrombosis and the level of glucose, uric acid, cholesterol, and triglycerides in the serum. The value of the percentage of alpha-lipoproteins in this respect awaits further confirmation.In contrast to the thrombotic tendency, the susceptibility to shock seems to have some connection with the serum cholesterol and more certainly with the triglyceride levels. The more saturated the dietary fats utilized, the higher were the triglycerides in the serum, and the more susceptible were the animals to shock, but not to thrombosis.
CHANGES IN ANTIGENICITY OF THE BRAIN OF THE CHICK EMBRYO
Authors: McCallion D. J. , Trott J. C.
Published: April 2011

Antiserum against 9-day chick embryo brain was obtained in rabbits. After absorption on chicken serum this antiserum was used in immunoelectrophoretic analysis of the brain of the developing chick. Several embryonic antigens common to all tissues that disappear at hatching were detected. Three adult neural-specific antigens were revealed. At least one neural-specific antigen, present in embryonic brain, disappears before hatching.
THE EFFECT OF GLUCAGON ON PREGNANCY IN THE RAT
Authors: Holloway S. A. , Stevenson J. A. F.
Published: April 2011

Pregnant Sprague–Dawley rats were given glucagon during the first, second, or third week of gestation. The effects on maternal and fetal physiology were studied and were compared with those of adrenaline. At all dose levels (0.5–2.0 mg/kg twice daily), glucagon significantly reduced maternal and fetal weights when given from day 13 to day 20 of gestation. Placenta weights were reduced, and there was a high incidence of premature and postmature deliveries, the latter associated with a high stillbirth rate. Glucagon (1.0 mg/kg twice daily) had little or no effect on maternal nitrogen balance or on fetal weight when given from day 0 to day 7 or from day 7 to day 13 of gestation. When administered from day 13 to day 20 there was a significant reduction in fetal weight compared with that of the controls, pair fed or fed ad libitum. Less nitrogen and probably more water were retained than in the controls. No significant increase in resting oxygen consumption was detected after injection of glucagon. The results indicate that the effect of excess glucagon on the fetus is mediated partly by a reduction in maternal food intake and partly by increased maternal protein catabolism. It seems unlikely to be due to an increase in resting expenditure of maternal energy or to the liberation of endogenous adrenaline. The increase in glucagon sensitivity in late pregnancy may be related to an increase in insulin resistance, known to occur at this time.
PERIPHERAL VASCULAR EFFECTS OF THE INSECTICIDE ENDRIN
Authors: Emerson Jr. Thomas E. , Hinshaw Lerner B.
Published: April 2011

The peripheral vascular actions of insecticides are relatively unexplored. The effects of the chlorinated hydrocarbon insecticide endrin on vascular resistances were investigated in forelimbs of anesthetized dogs. Total arterial, small-vessel, and venous segmental resistances were determined in innervated and denervated limbs following lethal infusions of endrin. Limb weight was recorded continuously in some experiments. Endrin administration resulted in large increases in total limb vascular resistance, most of which were due to an increase in small-vessel (small artery to small vein) resistance. Arterial and venous segmental resistances also increased. Early responses of innervated and denervated limbs were similar. Limb blood flow decreased markedly, and when measured, limb weight fell progressively. These effects appear to result primarily from an increased level of circulating catecholamines. Hyperexcitability to noise, bradycardia, and hypertension preceded the development of systemic hypotension.
FACTORS INFLUENCING THE NET CONSUMPTION OF GLUCOSE BY THE ISOLATED PERFUSED RAT LIVER
Authors: Gordon Ellen R.
Published: April 2011

Several factors have been found to influence the ability of the isolated rat liver to achieve and maintain a steady-state condition when receiving glucose at a constant rate. The net glucose consumed could be altered by starving the experimental animal for 72 hours, by changes in the blood of donor rats produced by starvation, by lowering of the pH of the perfusate, and by injury to the liver itself. In cases in which the net glucose consumption by the liver was lowered by starvation of the donor rats for 24 hours, the addition of insulin to the perfusate doubled the net consumption of glucose. These experiments demonstrate that insulin has an effect on the net consumption of glucose by the liver.
THE INFLUENCE OF RESERPINE ON CARDIOVASCULAR RESPONSES TO NORADRENALINE, TYRAMINE, AND PITRESSIN DURING RESPIRATORY ACIDOSIS
Authors: Nash Charles W. , Shivak Robert J. , Engelhardt Eva M.
Published: April 2011

The responses of vascular smooth muscle (VSM) to noradrenaline are depressed during respiratory acidosis, but it has not been reported whether the depression is effected at the adrenergic receptor or distal to it in the contractile mechanism. This paper reports an attempt to make that determination. As respiratory acidosis has been shown to cause an increase in circulating catecholamines, the assumption was tested that the depression is due to partial occupancy of the adrenergic receptor sites by endogenous noradrenaline released by the hypercapnia. Hind limbs of reserpine-treated and untreated dogs and cats were perfused and the responses of the VSM to intra-arterial doses of noradrenaline and pitressin were tested before and during hypercapnia. Hypercapnia was induced by respiring the animals with 30% CO2 in O2. The responses of isolated rabbit aorta strips to noradrenaline were also tested before and during treatment with a high concentration of CO2 in the aerating gas mixture. Tyramine was used to test for depletion of the noradrenaline stores by reserpine treatment.The following observations were made: (a) The maximum responses of VSM to noradrenaline were not depressed during high-CO2 treatment. Therefore, the observed depression of responses to submaximal doses is probably due to an influence on the drug–receptor or coupling reactions rather than the contractile mechanism, (b) The depressive action was not confined to adrenergic drug–receptor reactions, as the responses to pitressin were also depressed by hypercapnia. Therefore, the depression was probably located between the drug–receptor reaction and the contractile mechanism in some coupling reaction common to the two drugs. Partial occupancy of the adrenergic receptors did not appear to be the cause of the depression, (c) Tyramine appeared to have a direct effect on the VSM of reserpine-treated dogs, (d) Reserpine potentiated the responses of the VSM of dogs to tyramine and pitressin as well as to noradrenaline, (e) Reserpine reversed the effects of hypercapnia on the responses of the cats to noradrenaline. During hypercapnia in reserpine-treated cats the responses to noradrenaline were potentiated. It is proposed that hypercapnia may depress the responses of VSM to noradrenaline by influencing the availability of calcium for the contractile reaction.
THE EFFECT OF TRI-o-CRESYL PHOSPHATE INTOXICATION ON PHOSPHOLIPID SYNTHESIS IN CAT SPINAL CORD
Authors: Taylor J. D.
Published: April 2011

Demyelination was produced in cats by the intramuscular administration of 0.4 ml/kg of tri-o-cresyl phosphate (TOCP), and spinal cord was removed and assayed for lipid phosphorus. Spinal cord mince was incubated with choline bromide-1,2-C14, ethauolamine. HCl-1,2-C14, or L-serine-3-C14, and the incorporation of these substrates into the alkali-labile fraction was measured. A significant difference in the lipid phosphorus content of the caudal and cervical sections of spinal cord was observed in both normal and TOCP-treated animals. The lipid phosphorus and the percentage of the lipid phosphorus present as phosphatidyl ethanolamine was significantly increased in the cervical cord of the TOCP-injected cats. No differences were found in the incorporation of the labelled substrates into the phosphatides of the alkali-labile, alkali-stable acid-labile, or alkali-stable acid-stable phospholipids, or into the total lipid phosphorus of minced spinal cord from normal or TOCP-treated cats.
MECHANISMS OF HEMOCONCENTRATION IN THE DOG DURING ACUTE ENDRIN INSECTICIDE POISONING
Authors: Emerson Jr. Thomas E.
Published: April 2011

Hemoconcentration following intravenous administration of the chlorinated hydrocarbon insecticide endrin was investigated in sham-operated, splenectomized, and abdominal-eviscerated dogs. Isolated perfused lung preparations and those in which total venous return to the heart was monitored were also utilized. By 30 minutes after endrin the hematocrit had increased 14% in sham-operated animals but only 8% in splenectomized and eviscerated dogs. Blood pH fell to low levels in all groups. Pulmonary artery pressure increased in the constant flow perfused lungs after endrin; an early increase preceded a loss of lung weight. Pulmonary vascular resistance and left atrial and pulmonary artery pressures increased after endrin in the venous return studies. Hemoconcentration appears to result in part from addition of cell-rich blood from the spleen, and an increase in mean corpuscular volume secondary to the severe acidemia as observed in several experiments may also be involved. Loss of plasma fluid in the hepatosplanchnic area does not seem to occur, but pulmonary venous pressure was elevated, and loss of vascular volume from the lungs cannot be excluded.
EFFECT OF ENDRIN ON VENOUS RETURN AND CATECHOLAMINE RELEASE IN THE DOG
Authors: Reins D. A. , Rieger Jr. J. A. , Stavinoha W. B. , Hinshaw L. B.
Published: April 2011

Previous reports have shown that dogs treated with the insecticide endrin develop marked changes in blood pressure and heart rate accompanied by convulsions terminating in death. The present study was designed to determine the relationship between venous return (cardiac output), total peripheral vascular resistance, and hypertension seen in succinylcholine-treated dogs after a lethal dose of endrin. Experiments were performed on "intact" (viscera intact) and eviscerated dogs under conditions of total body perfusion. Results indicate that the rise in systemic arterial blood pressure depends primarily on increased cardiac output due to an elevated venous return. Total peripheral resistance does not change significantly in either group of animals. The abdominal viscera were the primary source of the increase in venous return after endrin. Adrenal glands were partially depleted of adrenaline, and increased levels of adrenaline and noradrenaline found in blood plasma may explain the marked alterations in systemic hemodynamics.
THE EFFECT OF X-IRRADIATION ON THE CELL SIZE DISTRIBUTION OF THYMUS LYMPHOCYTES
Authors: Vittorio P. V. , Blehm S. , Linkletter D.
Published: April 2011

The effect of X-irradiation on the cell size distribution of thymus lymphocytes was studied with the aid of an electronic Coulter cell counter.In the thymus the small lymphocytes were the most radioresistant and the large lymphocytes were repopulated before the medium-sized lymphocytes. As the radiation dose was increased from 50 to 400 r, there was a decrease in the large to small thymocyte ratio, and a longer time period was required for a return to the normal ratio. Single and repeated doses of X-irradiation produced much the same type of effect on the large to small ratio of both thymus and spleen lymphocytes, and it was concluded that the effects of X-irradiation on the cell size distribution of lymphocytes in the thymus and spleen were similar.
THE TEMPERATURE RESPONSE OF ACCLIMATIZED AND UNACCLIMATIZED RATS TO EXERCISE IN THE COLD
Authors: Thompson G. E. , Stevenson J. A. F.
Published: April 2011

Colonic and tail-skin temperatures of cold-acclimatized (4 °C for 4 weeks) and unacclimatized (4 °C for 1 day) rats were measured while they were being exercised on a treadmill (4.6 m/minute) in the cold (4 °C). In unacclimatized animals the colonic temperature increased to the same level as when they were previously exercised at 24 °C, but the changes in tail-skin temperature indicated only a small vasodilatation. In cold-acclimatized animals the colonic temperature increased to a significantly higher level than in unacclimatized animals before peripheral vasodilatation appeared, and this higher colonic temperature was maintained as exercise continued. In addition, the cold-acclimatized animals showed a higher tail-skin temperature during rest and a greater vasodilatation during exercise than the unacclimatized controls. Rats treated for 6 days at room temperature (24 °C) with a mixture of thyroxine (25 μg/100 g body weight per day) and cortisone (1 mg per rat per day) were exercised at 4 °C after being exposed to this temperature for only 1 day. The colonic temperature was controlled at a higher level in these animals than in saline-injected controls but peripheral vasodilatation was not greater.
EFFECT OF PHOSPHATES UPON EXPERIMENTAL SKIN CALCINOSIS
Authors: Gabbiani G.
Published: April 2011

Soft tissue calcinosis is produced at the site of subcutaneous injection of polymyxin in rats treated intravenously with lead acetate. This phenomenon is inhibited by ATP and pyro- and meta-phosphate, but is aggravated by mono- and di-basic orthosphosphate.
TISSUE CULTURE AND THE STUDY OF ANTICANCER AGENTS
Authors: Tolnai Susan
Published: April 2011

In a quest for potential antitumor agents, more than 100 fatty acids and their derivatives were tested against transplantable mouse tumors with both in vivo and in vitro methods. Three compounds, 2,3-decenoic acid, linoleic acid, and linolenic acid, were found to arrest the growth of three types of ascites tumor cells, while 2-nonenoic, 10-undecenoic, oleic, and arachidonic acids were effective to a varying degree. The cytotoxic effects of these unsaturated fatty acids on monolayer cultures of Ehrlich ascites tumor cells and of normal mouse embryos were evaluated in experiments in which graded concentrations of the test materials incorporated in the culture medium were used.
EFFECTS OF ALDOSTERONE, VASOPRESSIN, AND CORTICOSTERONE ON SALT AND WATER DISTRIBUTION IN THE NEUROHYPOPHYSECTOMIZED ADRENALECTOMIZED RAT
Authors: Friedman Sydney M. , Gustafson Brigid , Hamilton Dorothy
Published: April 2011

The separate effects of aldosterone, vasopressin, and corticosterone on salt and water distribution were examined in the neurohypophysectomized adrenalectomized rat with conventional partition methods for plasma and skeletal muscle. In the absence of countering hormones, even small amounts of aldosterone suffice to produce a gain in muscle sodium. This is usually associated with some degree of potassium loss and a tendency for the extracellular space to expand at the expense of cell water. Small doses of vasopressin, when not hormonaily opposed, suffice to produce a loss of muscle sodium, usually associated with a tendency for the extracellular space to contract in favor of an increase in cell water. Corticosterone, when not hormonally countered, produces effects similar to those of vasopressin and acts as a desalting agent.
THE DISTAL TUBULAR HANDLING OF NINHYDRIN-POSITIVE SUBSTANCES
Authors: Wright L. A. , Nicholson T. F.
Published: April 2011

The possible handling of ninhydrin-positive substances by the distal tubule was assessed by comparing the excretion of these substances from a kidney with damaged distal tubules with that from the undamaged contralateral kidney, which served as the control. The studies reveal that the distal tubule reabsorbs to a very limited extent alanine, asparagine, glutamic acid, glutamine, glycine, hydroxyproline, proline, possibly serine, and two unknown substances, all compounds which may take part in ammonia production.
THE EFFECT OF NUTRITIONAL STATE ON ABILITY OF THE RAT TO SWIM TO EXHAUSTION
Authors: Beaton John R. , Feleki V.
Published: April 2011

Following 9 days' provision of a high-protein (HPD), high-fat (HFD), or high-carbohydrate (HCD) diet (isocaloric), rats were made to swim to exhaustion in water at a temperature of 25–26 °C. Lead weight was strapped to the base of the tail at a level of 6% of body weight to increase the work load and decrease the exhaustion time. Under both ad libitum and restricted feeding conditions, animals fed the HPD had the longest exhaustion time, there being no apparent difference between exhaustion times of animals fed the HFD or HCD. Restriction of food intake increased the time to exhaustion. Provision of a meal just before swimming exercise decreased the time to exhaustion. Daily swimming for 15 minutes (training) prior to the test increased and decreased exhaustion time in HCD- and HPD-fed rats respectively with no significant effect on exhaustion time of HFD-fed rats.
METABOLIC EFFECTS OF HYPERPHAGIA IN THE HYPOTHALAMIC-HYPERPHAGIC RAT
Authors: May K. K. , Beaton J. R.
Published: April 2011

Metabolic effects of hyperphagia have been investigated in male rats in which hyperphagia was induced by bilateral, electrolytic lesions in the region of the ventromedial nuclei of the hypothalamus. In the early dynamic phase of hyperphagia, it would appear that increased body weight gain is a direct effect of increased energy intake not balanced by the observed increased spontaneous activity. In these animals increased lipogenesis (14C-acetate and 14C-glucose) and decreased lipolysis in vitro were evident with no evidence of altered thyroid function. Further, as determined by 35S incorporation in costal cartilage, the hyperphagia did not elicit an increased rate of skeletal growth. In the static phase, spontaneous activity was not increased, metabolic patterns were significantly altered in the direction of increased lipogenesis and decreased lipolysis, and there appeared to be a decreased uptake and release of 131I by the thyroid, which is suggestive of thyroid hypofunction.
SOME ELECTRICAL CHARACTERISTICS OF SUCROSE-WASHED FROG SARTORIUS MUSCLE
Authors: Mainwood G. W.
Published: April 2011

Transmembrane potential measurements were carried out with microelectrodes in frog sartorius muscles washed in buffered sucrose solution. After an initial fall the potential returns to a level determined by the extracellular potassium concentration. After about 20 minutes of washing, the cells develop a response to carbon dioxide dissolved in the surrounding medium. Increasing the extracellular carbon dioxide concentration leads to a reversible fall in transmembrane potential. This appears to be a specific effect of carbon dioxide since lowering the pH in the absence of CO2does not cause a significant potential change. It is postulated that this effect may be due to an efflux of bicarbonate ions.
AN ATTEMPT AT ESTIMATING EXTRAFIBER FLUID IN SMALL SKELETAL MUSCLES BY A SIMPLE PHYSICAL METHOD
Authors: Goldspink G.
Published: April 2011

Estimation of the extrafiber fluid volume in the biceps brachii muscle of the mouse was attempted by pressing the fibers into a thin layer. This caused the fluid from the spaces between the fibers to be displaced to the periphery of the fiber mass. As the thickness of the layer was known, the volume of the extrafiber fluid and the fibers was determined from their areas. The technique consisted of gently pressing the muscle between two glass plates. The thickness of the layer was controlled by plastic film spacers placed between the plates. The optimum thickness for mature mouse biceps muscle was found to be 125 μ. Measurements were carried out on muscles of different sizes, and it was found that the proportion of extrafiber fluid did not change very markedly during postembryonic growth. Investigations were also undertaken to ascertain the effects of starvation and deprivation of water. Starvation was found to increase the percentage of intrafiber water. Deprivation of water was found to result in a considerable decrease in the extrafiber fluid volume but to cause no dehydration of the fibers themselves.
THE EFFECT OF LOCAL TEMPERATURE ON INDIRECT VASODILATATION IN THE FEET
Authors: Gaskell Peter , Bray Garth M.
Published: April 2011

Lewis and Pickering reported in 1933 that warming occurred later in cool than in warm fingers in response to body heating. Factors which may be responsible were investigated. Measurement of rate of blood flow in the feet by venous occlusion plethysmography during body heating showed that vasodilatation in the feet occurred at the same time in a cool foot (18 to 23 °C) as in a warm (30 to 35 °C) but that warming of the cooler foot might be delayed for some time until the increase in flow was 0.5 ml/100 ml of foot per minute or more. In control experiments, with both feet in cool water or both in warm, the increase in blood flow during body heating started at the same time in both feet. Warming also began at the same time in both feet, but in the cool control experiments, warming often began later than did increase in flow. It is suggested that precooling of arterial blood may account for the delay in warming when the extremity is initially cool and the increase in blood flow is at first small during indirect vasodilatation.
THE EFFECT OF LOCAL TEMPERATURE ON THE REACTIVITY TO NORADRENALINE OF DIGITAL VESSELS
Authors: Gaskell Peter , Hoeppner David L.
Published: April 2011

The effect of local temperature on the in vivo reactivity of vascular smooth muscle was studied. Reactivity was measured as the increase in critical opening pressure (COP) of digital vessels caused by intravenous infusion of 5 μg of noradrenaline per minute. With one hand cool (22 °C) and the other warm (34 °C) in test experiments or both hands either cool or warm in control experiments, simultaneous measurements were made of the increase in COP of vessels in both middle fingers in response to the noradrenaline. In control experiments the mean increase in COP was similar in right and left fingers, but in test experiments the mean increase was greater in the warm finger than in the cool one. Warm vessels were more reactive to noradrenaline than cool ones (p < 0.01). Because a short period of ischemia is involved in the measurement of COP, other experiments were performed in which the effect of duration of ischemia on the COP, with and without a continuous intravenous infusion of noradrenaline, was ascertained. They suggested that the estimated COP would, in most cases, be about 3 mm Hg less than the COP existing just before the measurement. These results also indicated that although the rate of fall of COP during ischemia was slightly greater for a higher initial COP, the ischemia involved did not invalidate the comparison of the increases in COP caused by noradrenaline in warm and cool fingers, as an index of relative arteriolar reactivity in the test reactivity experiments.
UPTAKE OF51Cr AS AN INDICATOR OF METABOLIC CHANGE IN WHEAT ROOT TIPS
Authors: Bourque Geneviève , Vittorio P. , Weinberger Pearl
Published: April 2011

A consistent pattern of51Cr incorporation was observed in serial sections of the roots of two varieties of wheat, both vernalized and unvernalized. The changed metabolic state attendant on vernalization was reflected by a higher level of51Cr incorporation. A clear indication was given that51Cr uptake can be used as a sensitive indicator of metabolic change in wheat root tips.The mode of entry and binding of the trivalent and hexavalent forms of chromium was also investigated.
THE EFFECTS OF PERIODIC CHALLENGE ON THE RESPONSE OF α2-AP GLOBULIN AND OTHER ACUTE-PHASE REACTANTS OF RAT SERUM TO TISSUE INJURY
Authors: Weimer Henry E. , Humelbaugh Constance
Published: April 2011

The effects of periodic challenge with turpentine on the concentration of the acute-phase reactants of serum were studied in young, adult, male Sprague–Dawley rats. The initial injection of the phlogogenic agent was followed by rapid and significant increases in the concentrations of plasma fibrinogen, total serum glycoprotein, serum complement, and the α2-AP globulin and seromucoid fractions. Variable response patterns were observed on subsequent challenges and in the intervals between. The conclusion was drawn that the acute-phase reactants of serum do not respond in a uniform manner to repeated challenge with a phlogogenic agent, and by inference their synthesis must be regulated by several different mechanisms.
EFFECT OF ANGIOTENSIN ON THE RELEASE OF ACETYLCHOLINE FROM PREGANGLIONIC AND POSTGANGLIONIC NERVE ENDINGS
Authors: Panisset J. -C.
Published: April 2011

Angiotensin is known to stimulate the synaptic transmission of the cat superior ganglion and the contraction of the isolated guinea pig ileum; to determine whether these effects could be mediated by a cholinergic mechanism, both preparations were tested for the possible release of acetylcholine by angiotensin. The right cervical ganglion of 12 anesthetized cats was perfused with heparinized cat plasma, and the preganglionic sympathetic trunk was electrically stimulated supramaximally at 10-min intervals. After each stimulation, the acetylcholine content of the effluent was determined by bioassay. Angiotensin, injected intraarterially toward the ganglion in amounts ranging from 0.1 to 100 ng immediately before a stimulation period induced a 30 to 50% increase in acetylcholine output. Most effective doses ranged from 0.5 to 20 ng. Comparable experiments were carried out on coaxially stimulated strips of guinea pig ileum in Krebs solution. The addition of angiotensin, 1 ng/ml, was followed by a 4.3-fold increase in acetylcholine release during the period of contractile stimulation. From these two sets of data, it is concluded that angiotensin exerts a cholinergic action at the preganglionic level in the ganglion and at a postganglionic site in the ileum.
HISTAMINE-LIBERATING ACTIVITY OF SERUM PROTEIN EXPOSED TO DEAE-CELLULOSE
Authors: Levy M. , Bliss J. Q.
Published: April 2011

Dog serum protein fractions prepared by chromatography on DEAE-cellulose produced an increase in local small-vessel permeability with distinct wheal formation when injected intracutaneously into the animal from which the whole serum was obtained. This permeability activity also appeared when the serum was left unseparated by simple passage through a DEAE-cellulose column in terminal buffer. Bovine serum albumin also developed permeability activity when treated this way. Neither whole autologous serum nor bovine serum albumin left untreated, showed any permeability activity. The whealing responses to active material were always reduced or abolished (a) after the test animal was given 2 mg/kg of the antihistamine mepyramine, and (b) in areas of skin depleted of their endogenous histamine by local treatment with compound 48/80. It is suggested that simple exposure of some protein molecules to the DEAE grouping converts them into histamine liberators.
ON THE RHYTHMICAL ELECTRICAL ACTIVITY OF CERTAIN RHINENCEPHALIC STRUCTURES
Authors: McLennan H. , Graystone P. , Desautels Laurette
Published: April 2011

The bursts of electrical activity with a dominant frequency near 40 cycles/sec which characterize the records obtained from the amygdala, pyriform cortex, and olfactory bulb of cats, have been analyzed and yield the following results. (i) The frequency of the waves composing any single burst was constant, but varied widely from one burst to another. (ii) The bursts appeared earliest in the pyriform cortex, and subsequently in the olfactory bulb and various nuclei of the amygdala. (iii) A burst could originate in the cortex of either hemisphere, and thereafter appeared in the contralateral pyriform cortex earlier than in the olfactory bulb or amygdala of either side.
OXYGEN SUPPLY AND PERFORMANCE IN PEROMYSCUS: METABOLIC AND CIRCULATORY RESPONSES TO EXERCISE
Authors: Segrem Neri P. , Hart J. S.
Published: April 2011

Adult mice, Peromyscus leucopus novaboracensis, were exercised on a treadmill at various running speeds up to the highest obtainable at levels of oxygen ranging from 60 to 196 mm Hg. Oxygen consumption was not directly proportional to work rate as found in man and dog, and declined with a fall in the partial pressure of oxygen [Formula: see text] at the same work rate. As noted in other species, dependence of oxygen consumption on oxygen supply in Peromyscus varied with the level of exertion. The uptake at the highest speed was reduced by a relatively small fall in [Formula: see text] below normal air pressure whereas the uptake in resting mice was relatively insensitive to a reduction in [Formula: see text]. Heart rates varied in proportion to running speed and to oxygen consumption and were increased by a fall in [Formula: see text] at the same running speed.
DIVERGENT RESPONSES OF SERUM GLYCOPROTEIN FRACTIONS TO TISSUE INJURY IN ADRENALECTOMIZED RATS
Authors: Weimer Henry E. , Coggshall Vally
Published: April 2011

The effects of cortisol administration on the humoral response to turpentine challenge were investigated in adrenalectomized, sham-adrenalectomized, and intact rats. Qualitative and quantitative differences in response to challenge were observed for protein-bound hexose, total serum protein, and the α2-AP (acute-phase) globulin, fibrinogen, and seromucoid fractions. Adrenalectomy caused a pronounced reduction in the response of α2-AP globulin to tissue injury. A significant but less marked decline was observed for the seromucoid fraction, and the plasma fibrinogen response was not affected. The responses of seromucoid and α2-AP globulin were restored by replacement therapy with cortisol. Pharmacologic dosages of the hormone caused reduced levels of all three fractions irrespective of the surgical status of the recipient. It was concluded that the observed differences in response to challenge were related to the selective action and dosage of the hormone and to the state of the recipient.
A MODIFIED METHOD FOR THE COLORIMETRIC DETERMINATION OF HEPARIN
Authors: Jaques L. B. , Wollin A.
Published: April 2011

A sensitive accurate quantitative colorimetric assay for heparin with Azure A using the Beckman DK-2 spectrophotometer is described. Limits for the presence of impurities and precautions are given.
REPEATED MEASUREMENTS OF AEROBIC CAPACITY DURING A WEEK OF INTENSIVE TRAINING AT A YOUTHS' TRACK CAMP
Authors: Cumming Gordon R. , Goodwin A. , Baggley G. , Antel Jack
Published: April 2011

The maximal oxygen uptake of six boys and six girls, 18 to 16 years of age, showed no change with twice daily measurements over a 6-day period at a track camp where intensive physical training was carried out. Over the 6 days, submaximal pulse rate declined 6 beats/min for a constant load, and maximal pulse rate declined 7 beats/min. Boys and girls 13 to 16 years of age may run up to 45 miles daily without producing measurable declines in maximal oxygen uptake. Submaximal exercise pulse rates were higher in the evening compared with the morning. There was a tendency for submaximal exercise pulse rates to decline during training before any increase in aerobic capacity occurred. A prediction of aerobic capacity from submaximal tests based on pulse rate did not give a true indication of changes in aerobic capacity.
TETRAETHYLAMMONIUM-INDUCED CONTRACTIONS OF FROG'S SKELETAL MUSCLE: III. MECHANISM OF ACTION BY CALCIUM RELEASE
Authors: Beaulieu G. , Frank G. B.
Published: April 2011

The effects of changes in the extracellular calcium concentration on the muscle 'twitching' response induced by tetraethylammonium of the frog's sartorius muscle were investigated. Decreasing the calcium concentration of a solution bathing the muscle increased the sensitivity of the muscle to TEA stimulation. However, with a sufficient calcium reduction (to 0.108 mM in most preparations) the muscles became completely insensitive to TEA stimulation. In contrast, calcium reduction resulted only in an increased muscle sensitivity to carbachol stimulation. Increasing the calcium concentration greatly decreased TEA sensitivity, and at 2.16 mM calcium a TEA-induced muscle 'twitching' response no longer could be produced. At this calcium concentration carbachol sensitivity was reduced but not eliminated and neuromuscular transmission was essentially unmodified. In studies with the toe muscle, it was found that TEA could restore the potassium-induced contracture that had been eliminated by soaking the muscle in a calcium-free solution. This effect of TEA was dependent upon the presence of a store of bound calcium in the muscle. These results are consistent with the hypothesis that TEA acts by releasing calcium from binding sites on the nerve endings, leading to an increased excitability and instability of these structures and resulting in the muscle twitching response. Other effects of TEA similar to those of increases in calcium are due to an increased level of ionized calcium at nerve and muscle membranes which also results from the release by TEA of calcium from membrane sites.
THE EFFECT OF STORAGE ON THE COMPOSITION OF PLASMA PROTEINS
Authors: Baker D. G. , McFadyen D. M. , Carsten A. L.
Published: April 2011

Rat plasma was stored at 22 °C, 4 °C, or −20 °C for periods up to 16 days. The experimental design made it possible to resolve the influence of temperature and duration of storage on the protein stability as measured by the electrophoretic mobility on starch gels, concentration, and esterase activity of the protein components. Among the various protein components, both increases and decreases in concentration were found. Evidence was presented indicating that storage time rather than temperature contributed most to the alterations in protein stability. The possibility that the instability during storage might be related to conformational changes was suggested and the physiological significance of this relationship was indicated.
HEMATOLOGY OF THE INDIAN ELEPHANT (ELEPHAS MAXIMUS)
Authors: Nirmalan G. , Nair S. G. , Simon K. J.
Published: April 2011

Blood samples from 11 baby elephants, 14 tuskers, and 16 females comprising 5 pregnant and 11 nonpregnant nonlactating elephants (Elephas maximus) were analyzed to assess the hematological values and the influence of age, sex, and pregnancy on these. The results obtained show that, compared with other mammals, the erythrocyte count in the blood of elephants is low and the mean corpuscular volume (m.c.v.), mean corpuscular hemoglobin (m.c.h.), and erythrocyte sedimentation rate (e.s.r.) are high. The very high values for m.c.v. and m.c.h. and the low erythrocyte count seen in elephants suggest that in the evolution of blood though they are more advanced than reptiles and birds in having eliminated the nuclei from the erythrocytes, they are still in the primitive state compared with the other mammals in as much as their erythrocytes have not attained the efficiency in the transportation of blood gases that results from a reduction in size to facilitate numerical increase. A low erythrocyte count and packed cell volume, a high e.s.r., an increase in neutrophils, and a decrease in the percentage of lymphocytes and eosinophils characterize pregnancy. In baby elephants there is an increase in the total leucocyte and lymphocyte counts and a decrease in eosinophils.
CHANGES IN BLOOD LIPID CONCENTRATION AND CELL COUNTS FOLLOWING DECOMPRESSION SICKNESS IN RATS AND THE INFLUENCE OF DIETARY LIPID
Authors: Philp R. B. , Gowdey C. W. , Prasad M.
Published: April 2011

The effects were studied of dietary fat, alimentary lipemia, and a lipemia-clearing agent (partially depolymerized hyaluronic acid) upon decompression sickness by means of a standardized technique which produces a high incidence of "bends" in rats of suitable weight. Hematological changes were studied in rats fed meals of different fat contents and in rats with bends of different severities. The results indicated that alimentary lipemia increased susceptibility to bends; that this trend could be reversed partially with a lipemia-clearing agent; and that platelet counts decreased (i) after a fatty meal, (ii) after decompression, and (iii) after an attack of bends. In rats which were severely affected with aeroembolism both platelet counts and plasma lipids (as indicated by the plasma optical density) were greatly reduced and marked hemoconcentration was observed. It is postulated that intravascular bubbles triggered the aggregation of platelets and that lipemia, which increases platelet adhesiveness, exaggerated this effect. The obstruction of small vessels by thrombi composed of bubbles, platelets, and lipids could cause a loss of fluid from the vascular bed with subsequent hemoconcentration.
Determination of bradykinin in blood and bradykininogen in tissues
Authors: Sardesai Vishwanath M.
Published: April 2011

The rat uterus preparation was used to determine bradykinin and bradykininogen in blood. The use of an internal standard has permitted the quantitative estimation of the amount of bradykinin in the unknown samples. The effects of histamine, serotonin, catecholamines, and UML 491 (methyl sergide) on the assay of this polypeptide were studied. The results indicate that histamine in higher concentrations makes the uterus preparation insensitive to bradykinin. Serotonin and catecholamines increase the response of the uterus preparation to this polypeptide, and this effect can be blocked by UML 491. Normal human blood was found to contain bradykinin in the range 0.001 to 0.004 μg/ml and bradykininogen in the range 6 to 8 μg/ml. Bradykininogen was determined in different tissues from five species. Heart tissue had the highest bradykininogen content followed by liver, kidney, and brain.
Potentiation of toxicity of Sumithion by phosphamidon in the rat
Authors: Braid P. E. , Nix M.
Published: April 2011

Acute oral dosing of male rats with mixtures of Sumithion and phosphamidon produces a marked potentiation of toxicity as evidenced by increased mortality. While potentiation also occurs with female rats dosed with mixtures containing relatively low concentrations of Sumithion, the effect diminishes as the Sumithion concentration is increased. It is concluded that this potentiation is associated with a nonlinear thiophosphate conversion reaction.