bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Stimulation-Length Sequence on Shape of Length-Tension Diagram
Authors: Schottelius B. A. , Senay L. C.
Published: December 2017

Length-tension diagrams have been obtained from rat gastrocnemii stimulated under various stimulation-length sequences. The sequences were selected in an attempt to discover the origin of a secondary maximum on active and total length-tension curves, when these were derived by a commonly accepted technique. Two working hypotheses were advanced. The results indicate that several length-tension characteristics are dependent upon stimulation-length sequence, and that under the conditions examined the most important of these characteristics are extensibility and equilibrium length. As a consequence, neither working hypothesis appeared entirely satisfactory.
Effects of 3-Amino-1,2,4-Triazole (AT) on Catalase and Other Compounds
Authors: Heim Werner G. , Appleman David , Pyfrom H. T.
Published: December 2017

Rat liver and kidney, but not blood, catalase activity decreases profoundly within the first 3 hours after the intraperitoneal or intravenous injection of AT. AT administered orally to mice causes a reduction of liver catalase activity. The liver and kidney catalase activity of rats returns to normal about 7 days after a single intraperitoneal injection. Liver cytochrome c content, hemoglobin level and urinary urobilinogen excretion are not affected by AT administration. Liver peroxidase activity is decreased slightly 3 hours after injection of AT but returns to normal within 24 hours. Prolonged AT administration has no effect on the growth rate of young rats. AT reduces the catalase activity of plant tissue homogenates, liver homogenates and crystalline catalase in vitro but only at high concentrations. AT causes a reduction of chlorophyll content and catalase activity of plants when administered in vivo but the relative effect against these two constituents varies with species, physiological state and concentration.
Temperature Gradients in the Hypothermic Dog
Authors: Spurr G. B. , Horvath Steven M. , Hamilton L. H. , Hutt B. K.
Published: December 2017

Temperature gradients have been studied in 15 dogs subjected to hypothermia. In six of these experiments it was possible to maintain the rectal temperatures at approximately 25°C for from 4.5–34 hours. The results obtained indicate that there was little extraction of heat from the skin during progressive hypothermia. Initially the greatest amount of heat lost to the environment was from the muscular tissue. As the hypothermia progressed a greater and greater flow of heat came from the deep central regions and less and less of the heat lost to the environment originated in the muscular tissues. Throughout the period of stable hypothermia the temperature gradient between the core (rectum) and the muscular tissue of the thigh was significantly greater than during the control period, suggesting that the flow of heat depended primarily on conduction. The values for the ‘thermal circulation index’ of the hind footpad, thigh and foreleg were found to decrease as a result of hypothermia while the index for the ear and chest showed no significant change. These results, together with the evidence on the temperature gradients indicate that the induced hypothermia resulted in an increased volume of the ‘shell’ and a consequently reduced volume of the ‘core’. Since there was no appreciable change in the index for the chest, a relatively greater proportion of the heat lost to the environment must have occurred from the surface of the trunk.
Adjustments of the Circulatory System in Normal Dogs to Massive Transfusions
Authors: Huggins R. A. , Smith E. L. , Seibert R. A.
Published: December 2017

On the basis of the amount of blood transfused in cubic centimeters per kilogram the dogs were arranged into five groups: group I, 0.0–49.0 cc/kg, group II, 50.0–99.0 cc/kg, group III, 100.0–149.0 cc/kg, group IV, 150.0– 199.0 cc/kg and group V, 200.0–249.0 cc/kg. The determinations made in each group were plasma volume, plasma proteins, hematocrit and hemoglobin. Plasma including protein escaped rapidly from the vascular system even with the smallest transfusion and in the last two groups the plasma lost exceeded that infused. Thus, any method of determining blood volume based on measurement of plasma volume must be in error. The loss of plasma protein became progressively greater as the amount of transfusion increased. The apparent increase in measured red cell volume over the expected in groups I, II and III was probably the result of loss of dye from the circulation, giving an overestimate of plasma and red cell volume. There was no evidence that cells leave the circulation until the transfusion volume became very large ( groups IV, V) and hemorrhage supervened.
Fatty Acid Utilization by Adrenalectomized Rats
Authors: Perry W. F. , Bowen Helen F.
Published: December 2017

The production of radioactive CO2 by intact and adrenalectomized rats given 1 C14 octanoic acid and the production of radioactive CO2 and radioactive acetoacetic acid by surviving liver slices from adrenalectomized and unoperated rats using 1 C14 octanoic acid as substrate have been studied. It was found that the CO2 production and acetoacetic acid production in vitro and CO2 production in vivo did not differ in the two types of animals. These results suggest that the adrenalectomized rat does not utilize fatty acids at a higher than normal rate and that the previously reported decreased incorporation of acetate into fatty acids by the liver slices from adrenalectomized rats is a reflection of decreased hepatic lipogenesis.
Effect of Histaminase Inhibitors on Gastric Secretion
Authors: Ivy A. C. , Lin T. M. , Ivy Emma K. , Karvinen Esko
Published: December 2017

1-Isonicotinyl-2-isopropylhydrazine, ‘Marsilid,’ and isonicotinylhydrazine, ‘Rimifon,’ stimulate gastric secretion in a Heidenhain and Ivy transplanted pouch dog when given intravenously during the fasting basal state. The secretory threshold for these compounds, especially ‘Rimifon,’ is close to a toxic dose. Aminoguanidine given intravenously stimulates gastric secretion in the anesthetized dog and cat in doses which do not reduce blood pressure and do not give rise to evidences of toxicity. In the Heidenhain and Ivy transplanted pouch dog an intravenous threshold dose of aminoguanidine, an inhibitor of histaminase or histamine metabolizing enzyme I, decidedly augments the gastric secretory response to a small test-meal, even when the test-meal contains little or no histamine. Assuming on the basis of evidence published by Schayer and his colleagues (13–16) that aminoguanidine does not act directly on the parietal cell, it is concluded that histamine (or a substance inactivated by diamine oxidase) acts directly and physiologically to stimulate gastric secretion either by being released into the blood stream or by being released in the region of the parietal cell by a nonhistamine gastrin.
Enzymatic Activity of Radiated Exteriorized Salivary Glands
Authors: English James A.
Published: December 2017

It was previously determined that when salivary glands of rats were radiated in situ with 3–5000 r of 200-kv x-ray there was a significant increase in specific activity of the glucose-6-phosphate and isocitric dehydrogenases. At the same time it was observed that there were other more general effects from this localized radiation. The present study was designed to determine what effect radiation (2000 r) would have upon the enzyme systems of exteriorized salivary glands of rats under conditions wherein the rest of the animal was completely shielded. Under these conditions we observed no general effects upon the animals and even the weights of the radiated salivary glands were not significantly altered, whereas in the previous study this was not the case. The values for glucose-6-phosphate dehydrogenase were higher for radiated salivary glands in 17 out of 18 groups of animals, the average values in arbitrary units being 3.36 ± 0.71 for the nonradiated glands and 3.83 ± 0.67 for the radiated glands when all groups of rats were considered (probability 0.05). During the 2nd week following radiation, the increase in activity of this enzyme was greater, the values being 3.04 ± 0.48 and 3.80 ± 0.42, respectively (probability 0.01). There was not a significant change in isocitric dehydrogenase following radiation of the exteriorized salivary glands.
Effects of Sodium Fluoride on Nerve-Muscle Transmission
Authors: Koketsu K. , Gerard R. W.
Published: December 2017

Anticurare action of NaF at the neuromuscular junction is demonstrated and analyzed for various stages of impulse transmission from nerve to muscle. The e.p.p. of preparations blocked by d-tubocurarine is augmented by 0.5–10 mm NaF. The e.p.p. amplitude is increased about 2.5 times by 0.5–1 mm, nearly three times by 3 mm or higher concentrations, and some prolongation occurs. The e.p.p. of a preparation blocked by tetanization is also augmented promtly by NaF, and transmission is restored. In this case, the threshold voltage for propagated muscle responses is lowered. NaF has no effect on the normal muscle membrane potential, even in the end-plate region —nor has it any effect on the electrical threshold. The end-plate depolarization produced by acetylcholine is considerably increased by NaF; and the curve of NaF concentration against the increase of depolarization is identical with that of the increase of e.p.p. The time course of acetylcholine depolarization, when augmented by small concentrations of NaF produce some prolongation of the falling limb, but the curve is still quite different from one augmented by eserin. NaF has no effect on the frequency of spontaneous e.p.p.s, but it considerably augments the height of each individual miniature e.p.p. The augmentation of the e.p.p. produced by NaF is not explained by an anticholinesterase action; it is mainly due to an increased sensitivity of the end-plate to acetylcholine induced by the fluoride ion.
Effect of Certain Cations on Relaxation of the Glycerol-Extracted Heart Muscle of Frogs
Authors: Hawkins Lee W. , Smith John R.
Published: December 2017

Hearts of large bullfrogs ( Rana catesbiana) were extracted in 50% glycerol at –10 to –20°C. These hearts were then perfused with solutions of desired molarity, and contractions were measured by a compound lever attached to the ventricles. Perfusion was carried out with solutions containing magnesium, sodium, potassium or calcium chloride (using the molarities of these ions in Ringer's solution); the solutions were adjusted to ph 7.5 at room temperature. The salts were perfused singly or in various combinations. Ventricular contraction was induced by ATP (0.016 m, adjusted to ph 7.5) added directly to the perfusate. The data indicate that, following contraction of the hearts with ATP, the perfusion of Na, Mg and K cations enhance relaxation of the glycerinated hearts. Of these cations, the Na ion may be of particular importance in relaxation of the ATP-contracted muscle, for Na perfused alone caused a more rapid rate of muscle elongation. However, when the hearts were previously irrigated with Mg ion, perfusion with Na then provoked strikingly rapid relaxation of the glycerinated hearts. Ca ion was not observed to recontract the hearts after original ATP-contraction and relaxation by Na-Mg irrigation.
Effect of Several Cations on Transmembrane Potentials of Cardiac Muscle
Authors: Hoffman Brian F. , Suckling E. E.
Published: December 2017

The effects of changes in the extracellular concentrations of Ca, K and Mg on the transmembrane resting and action potentials of single fibers of the auricle, ventricle and specialized conducting system of the dog heart have been studied by means of intracellular microelectrodes. With respect to Ca, the three tissues exhibit quite different sensitivities. Changes in concentration of this ion alter the time course of the action potential recorded from auricle and ventricle but have little effect on the action potential configuration of the Purkinje fiber. In the latter tissue, on the other hand, pacemaker activity is most strongly enhanced by Ca depletion and excitability is lost at Ca concentrations permitting normal propagation in papillary muscle. The effect of K on the resting transmembrane potential is dependent on the simultaneous Ca concentration. The interrelationship is such that the depolarizing effect of high K is decreased by elevated Ca and the depolarization produced by low K is diminished by low levels of Ca. Changes in the concentration of Mg have little effect on the transmembrane potentials of cardiac muscle unless the level of Ca is low. Under this condition a simultaneous decrease in Mg gives rise to a marked prolongation of the action potential duration of both auricle and ventricle. Some evidence for the basic similarity of the processes underlying repolarization in these three tissues is presented and it is thought the normally encountered differences in their action potentials may be related to the sensitivity of each tissue to extracellular Ca.
Renal Function and Water Metabolism in Nutritional Deficiencies
Authors: Guggenheim K.
Published: December 2017

Excretion of a combined load of water and inulin is significantly delayed in rats suffering from lack of either pantothenic acid, pyridoxine and riboflavin. In view of the fact that treatment of the deficient animals with either ACTH or cortisone increased the excretion of both water and inulin, in contrast to normal control rats, it is concluded that the depressed glomerular filtration rate of these two substances is due to an adrenal insufficiency. In rats suffering from either protein or choline deficiency, as well as in normal rats treated with Pitressin, the excretion of inulin remains normal, whereas the water diuresis is delayed. These results, confirming previous findings, would appear to indicate an impaired hepatic inactivation of the posterior pituitary hormone in these nutritional deficiencies. Thiamine deficient rats also exhibit a delayed diuretic response to a combined inulin-water load, which cannot, however, completely be restored to normal by ACTH or cortisone.
Inactivation of Glucagon by Tissues in Vitro
Authors: Kenny A. J.
Published: December 2017

A series of experiments are described in which glucagon was first incubated with a tissue preparation, then recovered by an acid-alcohol extraction, and, finally, assayed by rabbit liver slices. Failure to recover added glucagon was interpreted as loss by inactivation. Boiled tissue regularly yielded a complete recovery of added glucagon. Numerous tissues from the rabbit inactivated glucagon, as did dog and rat liver. Rabbit blood and plasma produced relatively little inactivation of glucagon. The inactivating system was studied further in rabbit liver homogenates. The effect was enzymic in nature, the enzyme system being present in the supernatant after subcellular fractionation. Inhibition of the system by p-chloromercuribenzoate and cupric ions suggests that sulphydryl groups may be necessary for activity of the enzyme system. Insulin and a crude ACTH preparation also inhibitied the inactivation of glucagon. The insulin effect was one of competitive inhibition. However, a comparison of the properties of the enzyme system in rat liver with published characteristics of insulinase revealed several differences between the two systems.
Inhibition of Estradiol-17ß-Induced Uterine Growth by Δ1, 9α Fluoro-17 Hydroxycorticosterone
Authors: Velardo Joseph T.
Published: December 2017

Adult, albino rats of the Charles River strain, 100 days of age, weighing 190–210 gm, were bilaterally ovariectomized, and 1 week later were placed on experiments to ascertain the influence of Δ1, 9α fluoro-17-hydroxycorticosterone (ΔFF) on estradiol-17ß-induced uterine growth. The results indicate that ΔFF when administered in a daily dosage up to 0.20 mg for 3 days did not modify the weight of the uterus of the ovariectomized rat, whereas 3 daily dosages of 0.10 µg estradiol-17ß effected an increase of approximately 85% in uterine weight. When 0.05–0.20 mg ΔFF was injected daily, but at different sites, with 0.10 µg estradiol-17ß for the 3-day period, the response of the uterus to estradiol-17ß was markedly reduced from the estradiol-17ß-induced increase of 85% to 52% on the lowest dosage of ΔFF down to 24% on the highest dose (0.20 mg) of ΔFF. These experiments further indicate that the inhibition of estradiol-17ß-induced uterine growth could be partially reversed by increasing the dosage of estradiol-17ß. Comparatively, data at hand suggest that ΔFF > 9αFlF > compound F > compound E > Δ1E and Δ1F in inhibiting 0.10 µg estradiol-17ß on the uterus and the vagina of the ovariectomized rat. Moreover, the incorporation of an additional double bond in ring A (Δ1) and flourine atom in the 9α position of compound F enhances the uterine growth inhibiting activity of compound F. Of the numerous glucocorticoids and mineralocorticoids tested for ability to inhibit estradiol-17ß, ΔFF is by far the most efficacious.
Reappraisal of Ventricular Thresholds in Hypothermia
Authors: Hegnauer A. H. , Covino B. G.
Published: December 2017

Data presented elsewhere ( Am. J. Physiol. 181: 362; 553, 1955), purporting to show that the ventricular threshold is radically reduced during systole in acidotic hypothermic dogs, were obtained with an experimental stimulating technique now known to be inadequate for the purpose. The conclusions based on these experiments are therefore invalid. The problem of ventricular thresholds in hypothermia is currently being reinvestigated with results which indicate relatively slight deviations from the normal.
Contractile Properties of Actomyosin Threads and Bands Prepared From Dogs' Hearts
Authors: Dettli L. , Bing R. J.
Published: December 2017

The experiments deal with the results obtained on the contraction of actomyosin from dogs' hearts, using a newly developed ‘null-seeking’ device for measuring and recording ATP-induced isometric, isontonic and afterloaded contractions. A comparison was made of the relative shortening of actomyosin a) when the relative shortening of actomyosin threads was plotted against the load, b) when relative shortening of the threads was expressed as a function of their specific nitrogen content, c) when this relationship was determined for compressed actomyosin bands rather than threads. In several experiments, the tension developed during isometric contraction was related to specific nitrogen content. Results demonstrate that the scatter of observation was reduced by compression of the fibers to bands and by mounting the bands in a horizontal position when recording their contractions. Using afterloaded contractions, a definite inverse relationship was found in bands between shortening and load/unit of nitrogen.
Effect of Cortisone on Lipid Metabolism of Plasma, Liver and Aorta and on Retrogression of Atherosclerosis in the Rabbit
Authors: Dury Abraham
Published: December 2017

This study was made to assess the relative metabolic effects of cortisone in rabbits on a normal or high cholesterol diet. Cortisone was administered daily for 14 days to normal and atherosclerotic rabbits. Determinations were made of lipid distribution and phospholipid metabolism of plasma, liver and aorta of these groups compared with that of untreated, normal and cholesterol-fed animals. Aortas were examined and judged for severity of atherosclerosis. The most notable effects of administered cortisone on lipid distribution were the extent of mobilized neutral fat to the liver and the elevated level in the plasma. Cholesterol metabolism appeared to be differently affected by cortisone administration to animals on the two types of diet; in cholesterol-fed rabbits the plasma ester cholesterol was significantly depressed while in normal animals cortisone appeared to have promoted a hypercholesterolemia. Plasma lipid interrelationships of cholesterol-fed, cortisone injected rabbits were more like normal and different from that of untreated, atherosclerotic rabbits. The radioactivity data showed that plasma phospholipid turnover rate was increased while specific activity of aortic phospholipid was decreased in rabbits administered cortisone compared with that of the untreated groups. The Sf 12–400 classes of serum lipoproteins were increased in amount in normal and cholesterol-fed rabbits subsequent to administered cortisone. The metabolic findings are discussed with regard to their association with a marked degree of retrogression of the severity of atherosclerosis observed in the cortisone-treated rabbits.
Water and Electrolyte Exchanges Between Excised Rabbit Tissues and Plasma
Authors: Gaudino Mario
Published: December 2017

Freshly excised rabbit tissues did not maintain their water and electrolyte composition when immersed in vitro in plasma obtained from blood of the same animal. All gained water, chloride and sodium and, in general, lost potassium. Changes occurred with varying speed and degree for each tissue. Increases in skin appeared to be due to entrance of plasma or plasma filtrate. In tendon there were indications of a selective water imbibition, although similarities existed with skin changes. In muscle, liver and brain, chloride and sodium entered in larger proportion than explained by a plasma filtrate entrance. More sodium entered than potassium was lost with a resulting cation gain. In muscle and liver there was some evidence that sodium gain in excess of potassium loss could have been due to plasma or plasma filtrate entrance. In brain, all water and electrolyte movements seemed to be independent of each other. A relatively large proportion of the potassium content of muscle seemed to be readily exchangeable with plasma. The opposite was true for liver and brain. Control chloride and sodium tissue spaces of skin and tendon in most instances were greater than total water, a fact which made calculations of spaces of doubtful value for determining cellular and interstitial tissue fractions. Different sizes of radioactive sucrose, chloride and sodium spaces in muscle, liver and brain left the question of which was a true indicator of extracellular volume unanswered. Endogenous reductase activity measured with a tetrazolium salt was fairly well maintained after immersion in all tissues except brain, but no relationship between this activity and electrolyte composition could be ascertained. No activity was detected in tendon.
Effects of Induced Cold Torpor on Blood of Chrysemys Picta
Authors: Musacchia X. J. , Sievers Mary Louise
Published: December 2017

Effects of induced cold torpor on the blood concentration of the turtle, Chrysemys picta (Schneider) were studied. Hematocrits, specific gravity of whole blood and plasma, and plasma protein concentrations were estimated in a total of 163 control and experimental specimens. Turtles in cold torpor for 1, 2 and 3 months at 2° ±4°C showed a hemodilution. Three experiments with short term rapid induced cold torpor (up to 1 week at 0°C) also resulted in hemodilution. All the significant differences, between controls and experimentals, were in hematocrit and whole blood specific gravity. There were no real alterations of plasma protein and plasma specific gravity levels. The conclusion was reached that in the turtle corpuscles leave the circulating blood, and there is no significant disturbance in circulatory water balance during periods of cold torpor.
Inhibition of Gastric Secretion in Vivo by Iodoacetamide and N-Ethyl Maleimide
Authors: Hollander Franklin
Published: December 2017

The present investigation is an attempt to confirm and amplify in vivo the observation of Davenport that HCl secretion by mouse stomachs in vitro is blocked ‘nearly to zero’ by the irreversible enzyme inhibitors iodo acetamide (IAA) and N-ethyl maleimide (NEM). Aqueous solutions of the inhibitor, in various concentrations, were applied topically to canine Heidenhain pouches for a half-hour. In each such experiment, secretory capacity was measured directly before and after such treatment in terms of the output of free HCl ( Qhcl, expressed as mEq/2 hr.) following subcutaneous injection of histamine (0.1 mg/kg). In 13 such experiments, the posttreatment Qhcl was zero for at least 4 hours, thus demonstrating inhibition of acid formation in the living pouch dog. Contrary to the results in vitro, secretory response to histamine was complete; also, it recovered markedly within 24 hours, and probably completely within 48 hours following withdrawal of the inhibitor. In these experiments, and also in others in which histamine administration was withheld following application of the inhibitor to the mucosa, there was formed a nonacid viscous fluid (ph above 7.0) which contains hexosamine, other reducing substances, and much protein, and which has a variable buffering power. This material is suspected of being a mixture of gastric mucus, the still hypothetical ‘mucoid secretion’ and serous transudate formed in response to mucosal initiation.
Responses of Smooth and Striate Muscle to Alterations in Extracellular Electrolytes
Authors: Daniel Edwin E. , Bass Paul
Published: December 2017

Alterations in plasma electrolyte concentrations were produced by potassium deficiency, by adrenalectomy and by administration of cortisone and Adrenalin. The effect of these procedures on thigh and stomach muscle electrolytes was compared. Differences in response of the two types of muscle were analyzed and the conclusion drawn that different mechanisms control electrolyte composition of smooth and skeletal muscle. Implications of this are discussed. Calculations are presented which suggest that cortisone and Adrenalin enhance the potassium concentrating ability of skeletal muscle cells and that Adrenalin, in addition, restores the ability of muscle cells from adrenalectomized animals to exclude sodium.
Influence of Sodium, Potassium and Adrenal Hormones on Gastrointestinal Motility
Authors: Daniel Edwin E. , Bass Paul
Published: December 2017

The hypothesis that a negative potassium balance decreases gastrointestinal propulsive motility by depletion of intestinal potassium has been examined. Simple dietary deficiency in rats depleted intestinal potassium but did not increase gastrointestinal propulsion. Potassium deficiency accompanied by sodium restriction diminished gastrointestinal motility as well as potassium concentration in both the small intestine and lower bowel. Administration of excess cortisone or depletion of electrolytes by intraperitoneal sucrose solution decreased propulsion without depletion of intestinal potassium, though cortisone induced severe hypokalemia. Depletion of intestinal potassium apparently is not the common factor leading to decreased propulsion even when a negative potassium balance and/or hypokalemia are present. Dehydration and sodium depletion of the small intestine generally accompanied decreased propulsion, but the significance of these changes was not obvious. The gastrointestinal tract resists potassium depletion and the mechanisms controlling electrolyte distribution in it probably differ from those in skeletal muscle.
Effects of Total Body X-Irradiation and Plutonium Injection on the Cholinesterase of Erythrocytes and Brain
Authors: Sabine Jean C.
Published: December 2017

Both total body x-irradiation (25–300 r) and injected plutonium (0.63 µc Pu+6) produce an increase in the cholinesterase activity of erythrocytes of mice on the 4th day. In mice receiving 300 r, high values were found on the 3rd–5th days. Subsequently there was a sharp fall in this titer to values far below normal at the end of the 1st week. During the 2nd week recovery began and was apparently complete by the end of the 3rd week. The reticulocyte count was significantly depressed during the 1st week, and there was a small but significant reticulocytosis during the 3rd. In the plutonium-injected mice, the same early peak was observed and the same fall to values well below normal. There was no recovery during 63 days of observation. Data are presented for the 4th day following doses of x-rays from 15–300 r. From 25 r upwards there is a significant increase in the mean cholinesterase titer. There appears to be a relationship between the proportion of high individual titers and the dose, and the highest individual values were observed at 300 r. Data are presented on a large series of control mice, and these are shown to conform well to the normal distribution as evaluated by k-statistics.
Effects of Small Daily Doses of Growth Hormone on Nitrogen Output in Normal and Depancreatized Dogs
Authors: Gaebler O. H. , Liu C. H. , Zuchlewski A.
Published: December 2017

Storage of nitrogen was readily detected in normal bitches which received daily subcutaneous injections of 1.0 mg of purified growth hormone, and was very large after daily doses of 2.5–5.0 mg. In depancreatized bitches, receiving constant amounts of food and insulin, 2.5–5.0 mg daily doses of the same growth hormone preparations either failed to induce nitrogen storage, or caused nitrogen loss. Nitrogen storage was readily induced in depancreatized bitches by large single doses of purified growth hormone preparations, if the dose of insulin was adequately increased during the following days; a small daily dose of growth hormone, accompanied by an even greater increase in insulin dosage, was less effective. Failure to induce nitrogen storage in depancreatized animals with growth hormone alone occurred in experiments in which glucosuria was not increased; with growth hormone and additional insulin, nitrogen storage was induced despite a large increase in glucosuria. These findings suggest: that growth hormone and insulin are both involved in induction of nitrogen storage, that the function of growth hormone is not merely one of stimulating insulin output, and that the function of insulin in this connection is not purely one of counteracting the unfavorable effect of growth hormone on carbohydrate utilization.
Reserpine, Chlorpromazine and the Hypothalamus in Reactions to Oxygen at High Pressure
Authors: Bean John W.
Published: December 2017

Experiments were carried out on Sprague-Dawley rats to determine what effect reserpine and chlorpromazine might have on the toxic action of O2 at high pressure (OHP). Serpasil (Ciba) administered intramuscularly in 10 daily doses of 0.075 mg/kg before the animal's exposure to O2 at 85 lb. conferred some degree of protection against the O2 toxicity as manifest by a less extensive pulmonary hemorrhage and edema and a lesser lung weight than that of the controls. Single doses of 0.35 mg/rat were less effective. Chlorpromazine administered in single doses of from 13–35 mg/kg body weight gave a more pronounced protection; it delayed the onset of minimal and severe neuromuscular reactions and diminished their severity. It prevented or diminished the severity of pulmonary hemorrhage congestion and edema; prevented or markedly diminished the increase in lung weight usually seen in OHP and lowered the mortality. It diminished vasoconstriction in the mesentery; lessened congestion in the heart and liver and diminished the severity of intestinal hypotonia and hypomotility as compared with that of the controls. The protective influence of these agents is ascribed to their reportedly suppressive action at the hypothalamic level and the consequential inhibition of the augmentative influence of a) the adrenal cortex and medulla and b) of the sympathetic nervous outflow. The greater effectiveness of chlorpromazine may be attributed to its additional strong antiepinephrine action and that it possibly lowers metabolism. The data support the view that the increased hypothalamic activity in OHP augments the O2 toxicity through its influence on the hypophysis and adrenal cortex and through the sympathetic outflow to the adrenal medulla and adrenergic nerve endings; they also are in accord with the finding previously reported that peripheral sympathetic blocking agents afford some protection against the toxic action of OHP.
Metabolism of Glucose and Fructose in Liver of the Rat Subjected to Whole-Body X-Irradiation
Authors: Hill R. , Kiyasu J. , Chaikoff I. L.
Published: December 2017

Metabolism of glucose and fructose in the liver of the rat exposed to 1,000 r of whole-body x-irradiation was studied. Liver slices prepared from normal rats and from irradiated rats were incubated with C14-glucose and C14-fructose, and the conversion of the C14 to CO2, glycogen and fatty acids was measured. The recoveries of C14 in these products from the labeled glucose were greatly reduced in the experiments carried out 24, 48 and 72 hours after irradiation. The C14 recoveries in the corresponding experiments with C14-fructose were in the normal range. A single intravenous injection of glucose on the 3rd day after the irradiation was followed by no increase in liver glycogen. The same treatment with fructose doubled the glycogen content of the liver. The continuous intravenous administration of glucose, begun immediately after the irradiation and maintained for 3 days, resulted in liver glycogen values of 0.7–1.9%. The same course of treatment with fructose resulted in glycogen values of 4.2–5.0%. Fasting was ruled out as an explanation of the defective glucose utilization observed in the liver of the irradiated rat. Possible sites of action of ionizing radiations on the paths of hexose metabolism are discussed.
Quantitative Changes in Foot Blood Flow in the Dog Following Sympathectomy and Motor Denervation
Authors: Ederstrom H. E. , Vergeer T. , Rohde R. A. , Ahlness Paul
Published: December 2017

In dogs with unilateral lumbar sympathectomy blood flows were higher in the operated foot for about 3 days; later this foot had lower flows under anesthesia. Vasodilator drugs given intravenously or intra-arterially increased blood flow in the chronically sympathectomized foot, indicating that anatomical narrowing was not significant in the vessels. Temperature studies showed that the normal foot became warmer under anesthesia, but this was not true of the operated foot. Similar results were found following chronic motor denervation of the foot. These experiments suggest that the sympathectomized or denervated foot vessels were constricted by some circulating substance that was less effective on normal vessels.
Renal and Arterial Effects of Serotonin in the Anesthetized Rat
Authors: del Greco F. , Masson G. M. C. , Corcoran A. C.
Published: December 2017

Serotonin infused intravenously in anesthetized rats brought into osmotic diuresis with mannitol is antidiuretic in doses of more than 5 µg/kg/ min. This effect is dependent on decreased glomerular filtration and is largely independent of the changes in blood pressure. The renal and arterial pressure effects of serotonin are prevented, but not reversed by intravenously injected lysergic acid diethyl-amide and bromo-lysergic acid diethyl-amide.
Kinetics of Change in Spike Height During Anodal Polarization of Isolated Single Nerve Fibers
Authors: Schoepfle Gordon M.
Published: December 2017

The time dependent change in magnitude of the nodal action potential was analyzed as a function of time and of change in membrane potential during brief intervals of anodal polarization. The time course of this function involves an exponential term whose time constant decreases to a limiting value as extent of membrane hyperpolarization is progressively increased. While the time course of change in spike height cannot be correlated with any change in membrane potential induced by the polarization, the kinetics suggest that the sodium inactivation mechanism of Hodgkin and Huxley is sufficient to account for the results obtained. Brief direct current pulses elicit changes of membrane potential during activity which indicate that an augmented change in resistance of the hyperpolarized node is sufficient to account for the time dependent increase in spike height. These findings are consistent with the Hodgkin-Huxley scheme in that hyperpolarization of the squid axon membrane at constant membrane potential inhibits ‘sodium inactivation’ thereby allowing sodium conductance and sodium current to attain greater than normal values at peak time of activity. It is concluded that no change in emf of the membrane need be postulated in order to account for the time dependent increase in spike height during hyperpolarization of normal or depressed nodes.
Effect of Volume and Rate of Inflation and Deflation on Transpulmonary Pressure and Response of Pulmonary Stretch Receptors
Authors: Davis Harry L. , Fowler Ward S. , Lambert Edward H.
Published: December 2017

Action potentials of single vagal afferent nerve fibers from slowly adapting pulmonary stretch receptors, transpulmonary pressure and rate of air flow were recorded in anesthetized cats with open thoraxes during varied volumes and rates of inflation and deflation of the lungs. Both discharge frequency and total transpulmonary pressure varied with lung volume and also with its rate and sign of change. Effects of acceleration of volume on discharge frequency were not observed. The receptors provide signals related to the work of breathing.
Role of Carbonic Anhydrase in Anion Excretion in the Alligator
Authors: Coulson Roland A. , Hernandez Thomas
Published: December 2017

The influence of carbonic anhydrase inhibition on the excretion of exogenous sulfate, phosphate, bicarbonate and chloride was studied by injecting large amounts of salts both with and without Diamox. Renal carbonic anhydrase is necessary for the conservation of chloride by the alligator. Diamox had no effect on the excretion of sulfate or phosphate, therefore it is unlikely that carbonic anhydrase is normally involved in excretion of these ions. Although urinary CO2 after NaHCO3 injection was decreased by Diamox, it is improbable that this represents any influence on the excretion of filtered bicarbonate. It is postulated that this decrease is due to the inhibition of tubular production of CO2. Carbonic anhydrase inhibition leads to a slight but probably significant increase in K excretion.
Effect of Estrogen on the Peripheral Utilization of Thyroid Hormones
Authors: Feldman Joseph D.
Published: December 2017

The effect of estrogen on the peripheral utilization of exogenous and endogenous radiothyroxine and exogenous radiotriiodothyronine was studied in thyroidectomized castrate and in castrate rats. Estrogen did not affect the disappearance rate of these hormones from serum nor their space of distribution. Estrogen increased urinary excretion and decreased fecal excretion of radioactive products compared with controls following the administration of radiotriiodothyronine, but it did not influence the excretion of radioactive products after the injection of radiothyroxine or I131. Radiotriiodothyronine was utilized more rapidly than radiothyroxine.
Apparent Volumes of Distribution of Water, Electrolytes and Hemoglobin Within the Lung
Authors: Fishman A. P. , Becker E. Lovell , Fritts H. W. , Heinemann H. O.
Published: December 2017

The virtual volumes of distribution of water, sodium, chloride and hemoglobin have been measured in the fat-free wet lung of the dog. Even after correction for the red cell content of the lung, it appears that the virtual volumes of distribution of sodium and chloride in the lung are large as compared with other tissues. It is inferred that the sodium and chloride ‘spaces’ include a substantial quantity of fluid lining the alveolar membranes.
Sexual Development in Male Rats Treated With Cortisone
Authors: Hanson Russell O. , Blivaiss Ben B. , Rosenzweig Robert E.
Published: December 2017

Immature male rats were treated with 1.0 mg cortisone acetate daily for 2 or 4 weeks starting at 23 days of age and were maintained on paired or ad libitum feeding regimes. Body, adrenal and thymus weights were reduced as compared to control animals. Actual testes weights were usually reduced less than body, liver or kidney weights. The ratios of testicular to body weight were significantly increased in the animals autopsied at the end of treatment. Histological examination of the testes revealed no significant alterations from normal. The ratios of seminal vesicle and ventral prostate weight to body weight were significantly decreased in all groups of ad libitum-fed animals and in pair-fed group autopsied at the end of 2 weeks of treatment. There were no significant changes in the other pair-fed groups. No modifications were observed in the histology of these organs. Pituitary glands removed from pair-fed animals at end of treatment with cortisone for 2 weeks appeared to have a higher GTH content than in the controls as indicated by the growth of the ovaries of immature rats injected with suspensions of these glands. Pituitary glands taken from other pair-fed groups and from all ad libitum-fed groups usually showed a lesser GTH content than in controls.
Evidence for a Medullary Inspiratory Pacemaker
Authors: Brodie David A. , Borison Herbert L.
Published: December 2017

Experiments on central respiratory regulation were performed with unanesthetized cats which were both decerebrated and decerebellated. Electrical stimulation of a circumscribed area in the floor of the fourth ventricle in the medullary preparation consistently produced an increase in the rate of gasping. In the decerebrate animal, stimulation of this area converted the respiration into a gasping form of breathing which varied in rate and amplitude according to changes in stimulus parameters. Electrical stimulation of the medial reticular formation in the medullary animal revealed a functional separation of gasping and sustained inspiratory responses. Cauterization of the medullary tegmentum in the decerebrate preparation produced gasping. In the medullary preparation it was necessary to destroy the dorsal half of the medulla in order to abolish gasping. Surface cauterization of the medullary tegmentum prevented the rate-stimulating effect of cyanide which is regularly evocable in the animal with intact medulla. Because of the increasing need for revised terminology in central respiratory physiology, a new set of terms, namely, oscillator, modulator, integrator, and pacemaker, was incorporated in a functional concept of the central control of respiration.
Role of Autonomic Nervous System in Maintenance of Cerebral and Renal Hypertension
Authors: Rothman Sol , Drury Douglas R.
Published: December 2017

The blood pressure responses to various drugs were investigated in renal hypertensive, cerebral hypertensive and normotensive rabbits. Hexamethonium bromide and Dibenamine reduced the blood pressures of renal and cerebral hypertensives. Effects in the normal were insignificant. The cerebral hypertensive's blood pressure was slightly affected by benzodioxane. Blood pressure was not reduced at all in the other groups. Blood pressure of the renal hypertensive rabbit was greatly reduced by Veriloid and dihydroergocornine. Blood pressures of cerebral and normal animals were affected to a lesser degree. The results suggest that maintenance of hypertension in the cerebral hypertensive rabbit depends on an overactive sympathetic nervous system, possibly due to the release of medullary pressor centers from inhibitory impulses originating in higher centers; whereas, the maintenance of hypertension in the renal hypertensive rabbit may be attributed to an increased reactivity of the peripheral vasculature to a normal sympathetic tone.
Development of the Sex Difference in Blood Pressure of the Chick
Authors: Weiss Harold S. , Ringer Robert K. , Sturkie Paul D.
Published: December 2017

In order to establish the age and manner in which the sex difference in blood pressure of the adult white leghorn chicken develops, periodical blood pressure measurements were made on chicks between 3 and 34 weeks of age. There were no consistent differences in pressure between the sexes under 8 weeks of age. Between the 8th and 13th weeks, pressures began to diverge, and within 4–8 weeks a 26–30-mm sex difference in systolic pressure developed. Significant divergences occurred also in diastolic and pulse pressure. The sex divergence was due primarily to a rise in male pressure, the female level remaining comparatively stable. Net changes in male parameters during the period of rapid development of the sex difference in pressure were: body weight + 219 gm, systolic pressure + 26 mm, diastolic pressure + 16 mm and heart rate –22/ min. The age at which the sex difference in pressure begins and its rate of development appear to be related to sexual maturation in the male. However, no significant correlation between the rising male pressure and testes or comb size could be shown. Normal chick blood pressure values prior to the sex divergence differ within strains of white leghorns and for the two groups used here, between 7 and 9 weeks of age, were 150/130 and 162/136 mm Hg.
Capacity of Muscle Fiber Membrane
Authors: Tasaki I. , Hagiwara S.
Published: December 2017

Using two or three microelectrodes inserted into single muscle fibers of the toad sartorius, the electric impedance of the muscle fiber membrane was measured with a.c. between 25 and 1500 cps. It was found that the capacity of the muscle fiber membrane is practically independent of the frequency of the measuring a.c. The membrane capacity determined from the time constant of potential rise in the foot of a propagated muscle action potential agrees with the value determined by a.c. impedance measurement. It was emphasized that the a.c. method of determining the cable constants of the muscle fiber (based on eq. 1 under methods) is simple and gives satisfactory results.
Effects of Temperature on Minimal Metabolism of the Hypothyroid and the Normal Rat
Authors: Leidig Raymond , Gray Gary M.
Published: December 2017

The oxygen consumption and rectal temperature of thyroidectomized and intact white rats were measured at 23°C, 28°C and 33°C. The oxygen consumption of the thyroidectomized rats was minimal at 33°C while that of the controls was minimal at 28°C. Rectal temperatures were consistent with the hypothesis that the critical temperature for the thyroidectomized rat is significantly higher than that for the intact animal.
Reduction of Febrile Response to Bacterial Polysaccharide Following Incubation With Serum
Authors: Rall David P. , Gaskins James R. , Kelly Margaret G.
Published: December 2017

Effect of incubation of fresh rabbit serum with a bacterial polysaccharide from S. marcescens on pyrogenicity was examined in normal and tolerant rabbits. In contrast to a number of other reports, no evidence of augmentation of pyrogenicity was obtained; in fact, inhibition of pyrogenicity was frequently seen, particularly in the tolerant animals. Increasing the time of incubation or the amount of serum resulted in further reduction of pyrogenicity. Heating the serum to 68–70°C, but not to 58°C altered this effect on pyrogenic action.
Differentiation Between Two Forms of Angiotonin by Means of Spirally Cut Strips of Rabbit Aorta
Authors: Helmer O. M.
Published: December 2017

By means of a spirally cut strip of rabbit thoracic aorta, it has been shown that angiotonin exists in two forms. One form, angiotonin II, causes a contraction of the strip. The other, angiotonin I, is inactive. They are equally pressor when injected intravenously in animals. An enzyme in plasma converts the inactive form to the active form. The identical pressor activity can be explained by the excess of the converting enzyme in the plasma of the intact animal which rapidly converts angiotonin I to angiotonin II. Some patients with hypertension have a greater content of the converting enzyme in their plasma than is found in plasma of normotensive subjects. In addition to the converting enzyme, other factors in plasma enhance the ability of angiotonin and catechol amines to induce constriction of the strip of aorta. These factors may sensitize the mechanisms in the muscle which set up the process of contraction.