bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood sugar response of dogs exposed to hypoxemia and/or hypocapnia
Authors: Biddulph Clyde , Van Fossan D. D.
Published: December 2017

Blood sugar levels of 93 dogs are reported. In animals in which respiration was controlled and hypoxemia or hypocapnia induced for 15 minutes, there was no change in blood sugar. However, there was an elevation when hypocapnia and hypoxemia were combined. Exposure for 30 minutes elevated blood sugar to a greater extent in the hypoxemic group than in the combined hypocapnic and hypoxemic group, whereas hypocapnia alone produced no change. Exposure of pentobarbital sodium-injected or uninjected dogs to 30,000 feet simulated altitude for 15 minutes failed to produce a statistically significant increase in blood sugar, although evidences were observed of a physiologically important increase.
Strain differences in urinary hydroxycorticosteroids in guinea pigs
Authors: Nadel E. M. , Young B. G. , Hilgar A. G.
Published: December 2017

Because of previously noted variations in the urinary excretion of corticosteroids when guinea pigs of different genetic background were utilized in various experimentally induced pathological conditions, a study of the daily excretion of three unconjugated, polar corticosteroids (6ß hydroxycortisol, 2α hydroxycortisol and cortisol) was undertaken over a 24-day period in noninbred (Hartley albino) as well as inbred (strain 2 and strain 13) guinea pigs, prior to and immediately following the administration of 10 u of ACTH using established methods. Prior to ACTH treatment the summed daily excretion of these three free corticosteroids was 40γ, 63γ and 48γ, while following ACTH the excretion was 285γ, 238γ and 166γ for Hartley, strain 2 and strain 13 animals, respectively. Prior to ACTH treatment the major corticosteroid excreted by all three animal groups (10 to a group) was 2α hydroxycortisol. Following ACTH the major polar corticosteroid excreted by noninbred Hartley animals was cortisol while the major polar corticosteroid excreted by the inbred Strains was 2α hydroxycortisol. Although the excretion of 2α hydroxycortisol as the major free normal polar corticosteroid was unanticipated, the high production of cortisol in this species is well known and has been offered as partial explanation for successful hetero and homoiotransplantation in this species.
Adrenal and blood Δ4-3-keto-corticosteroids following various treatments in the chick
Authors: Newcomer W. S.
Published: December 2017

A single injection of ACTH and acute stress (restraint) were followed in 6 hours by nonstatistically significant decreases in total Δ4-3-keto-corticosteroids in adrenals and plasma and a statistically significant ( P < .05) blood acidophilia. Chronic treatment (7 or 15 days) produced statistically significant changes in free Δ4-3-keto-corticosteroids in adrenals following ACTH (>); hexestrol (<); hydrocortisone (<); and o,p'-DDD (<) and in plasma following hexestrol (<). o,p'-DDD produced a statistically significant ( P < .025) decrease in total steroids of plasma. Possible physiologic explanations for these effects are discussed.
Role of gluco- and mineralocorticoids in salt and water metabolism of adrenalectomized dogs
Authors: Swingle W. W. , DaVanzo J. P. , Glenister D. , Crossfield H. C. , Wagle G.
Published: December 2017

Daily doses (5 mg) of 1-dehydrohydrocortisone reduces plasma Na and Cl of nonfasted adrenalectomized dogs to levels characteristic of severe insufficiency. The animals remain active and vigorous despite the distorted plasma electrolyte pattern. Blood pressure and plasma volume remain at or near control values. The glucocorticoid maintains a normal internal distribution of fluid and certain electrolytes between intra- and extracellular compartments. Aldosterone even in large doses apparently lacks those properties necessary to enable the fasted adrenalectomized dog exhibiting symptoms to shift fluids from one compartment to another hence is incapable of reviving animals from insufficiency and restoring activity and vigor. The data suggest that the primary action of aldosterone is on the kidney and through renal control of Na excretion serves to regulate the fluid and Na content of the extracellular compartment.
Thyroid status and embryonic mortality in swine
Authors: Brunstad George E. , Fowler Stewart H.
Published: December 2017

Three lots of 10 Palouse gilts each were used to test the effect of altered thyroid activity on embryonic mortality in swine. Two lots received 0.15% thiouracil and 0.0123% thyroprotein, respectively, in a basal ration; the third lot served as the control. All gilts were assigned to treatment groups at first estrus, bred to fertile boars at third estrus and slaughtered 38 days post coitum. An analysis of variance revealed no statistically significant differences among lots for: ovulation rate, embryonic mortality during the first 38 days of gestation, or number of normal embryos at 38 days post coitum. Crown-rump lengths of normal embryos carried by thyroprotein-treated and control gilts were longer than those of normal embryos carried by thiouracil-treated gilts ( P < 0.01). There was a trend toward lowered ovulation rate and reduced embryonic mortality in the gilts receiving thyroprotein. The significance of these results is discussed in relation to BMR and pregnancy in women.
Increase in histidine decarboxylase activity of rat skin following treatment with compound 48/80
Authors: Schayer Richard W. , Rothschild Zuleika , Bizony Piroska
Published: December 2017

Repeated injections of rats with compound 48/80, a histamine liberator, results in a marked increase in histidine decarboxylase activity of the skin. The increase is roughly proportional to the duration of treatment. This eliminates activation of pre-existing histidine decarboxylase as a probable mechanism. The increase can be demonstrated in intact rats; therefore, rat skin histidine decarboxylase is an adaptive enzyme. It seems probable that 48/80 treatment leads to the production of new, resistant mast cells which are particularly active in forming histamine. This speculation is compatible with reports from other laboratories of histological studies on rats given 48/80. Implications of this finding are discussed.
Effect of acute fasting in the rat on water and electrolyte content of serum and muscle and on total body composition
Authors: Huth E. J. , Elkinton J. R.
Published: December 2017

Thirteen acutely fasted male adult rats were compared with six fed controls in respect to serum electrolyte levels (7 rats), total carcass (7 rats) and skeletal muscle composition (13 rats). Of the serum electrolyte levels only potassium was mildly depressed; there was no evidence of hypochloremic alkalosis or of hyponatremia. The loss of weight ranged between 25 and 37% of the initial value (mean = 32%). Total body fat was decreased most (mean = –97%). Lean body mass was relatively increased from 90 to 99% of the final body weight, but was absolutely decreased by 25% of the initial value; the ratio of water to fat-free solids was unchanged. In the total fat-free carcass, chloride was increased more than sodium, potassium was decreased relative to the total wet tissue, to total water and to nitrogen. In fat-free skeletal muscle, chloride and the chloride/sodium ratio only were increased. Either the extracellular fluid taken as the chloride space was expanded or chloride was sequestered or both. On the former assumption, intracellular water, sodium and potassium concentrations were unchanged.
Some drug effects influencing barbiturate facilitation of water ingestion
Authors: Schmidt H. , Moak S. J.
Published: December 2017

Pentobarbital was studied in combination with chlorpromazine and a stimulant barbiturate (5 ethyl, 5, 1, 3, dimethyl-2-butenyl barbituric acid) with respect to water intake in the rat. Each depressed water intake when administered alone. Pentobarbital increased drinking in the dosage employed. Chlorpromazine blocked totally the usual pentobarbital facilitation so that the combined effect was the same as that for chlorpromazine alone. The stimulant barbiturate antagonized the pentobarbital effect so that a constant difference between the stimulant and its control was obtained. The effect of the sodium salts of barbital, pentobarbital and phenobarbital upon water intake in the 23 1/2-hour water-deprived rat was also studied. A significant parabolic relationship was found between water intake and dosage, with water intake rising at low dosages and falling at higher dosages. The dosage of the drugs investigated yielding maximum facilitation of water intake varied with the hypnotic dosage. Finally, the extent of facilitation of water intake was found to vary for the different drugs. Two major conclusions are drawn: first, there is a hypnotic dimension of action affecting water intake within the barbiturate family; second, there is another dimension of action which relates to the extent of facilitation.
Long-term observations of spontaneous electrical activity of the uterine smooth muscle
Authors: Kao C. Y.
Published: December 2017

The spontaneous electrical activity of uterine smooth muscle was rather variable when acute observations were made. Therefore, a series of chronic experiments was performed with implanted electrodes to monitor a group of myometrial cells under different physiological conditions for periods up to eight weeks. The results showed that consistent behavior of myometrial cells could be observed provided similar hormonal status was maintained. Action potentials were rare or absent in myometrium of oophorectomized animals but were caused to appear by estrogen. In the pregnant uterus, action potentials increased both in amplitude and frequency of discharge as parturition approached, reached a peak at that time, and then declined in the postpartum days. The results indicated that in estrogen treatment and in parturition activities of myometrial cells were more synchronous. There was suggestive evidence that there were central impulses initiating activity in the pregnant uterus, and that the responses of the myometrium were affected by the local conditions.
Plasma triglycerides and unesterified fatty acids in lymph-infused dogs
Authors: Spitzer John J. , Roheim Paul S.
Published: December 2017

Plasma triglyceride and UFA levels were studied in the femoral artery, femoral vein, portal vein and hepatic vein in the course of the infusion of lymph containing I131-labeled triglycerides. The liver and abdominal region removed triglycerides frequently. Marked disappearance of triglycerides was found in the leg during and shortly after infusion. The negative arteriovenous difference in UFA in the femoral vessels of normal dogs disappeared during the infusion and reappeared later in the experiments. The liver continued to remove and the abdominal region to mobilize UFA after the infusion.
Role of catecholamines on energetics of the heart and its blood supply
Authors: Gerola A. , Feinberg H. , Katz L. N.
Published: December 2017

The effects of continuously infused intravenous l-epinephrine and l-norepinephrine (5 gamma/ kg/min.) were determined in the open-chested anesthetized dog prepared for measurement of total coronary flow and myocardial oxygen consumption. When catecholamines were infused at any fixed cardiac output, cardiac oxygen consumption rose in association with increases in blood pressure and heart rate, while cardiac external mechanical efficiency declined. The significance of the product (blood pressure times heart rate) as an index of the total cardiac effort, as indicated by the myocardial oxygen requirement, is considered in view of the alterations brought about by catecholamines in this relationship. The decline in the coronary A-V oxygen difference, the percentage of oxygen extracted by the heart and the ratio (cardiac oxygen consumption/oxygen availability) and the rise in coronary venous oxygen, are all attributed to a direct action of catecholamines on the coronary vessels. Despite their new levels, the coronary venous oxygen, content and the coronary A-V oxygen difference remain fairly constant as the cardiac effort and its oxygen requirement vary during catecholamine infusion.
Succinate-cytochrome c reductase, cytochrome oxidase and aldolase activities of denervated rat skeletal muscle
Authors: Hearn George R.
Published: December 2017

Young adult male Wistar rats with an average beginning weight of 294 gm had a segment of the right sciatic nerve removed. The nonoperated left leg served as a control. Succinate-cytochrome c reductase, cytochrome oxidase and aldolase activities, total RNA-P, total DNA-P and total protein were determined for both the denervated and control gastrocnemii muscles. The results for the enzymatic activities were expressed in terms of unit activity and total activity. The denervated muscles had significantly less enzymatic activity, RNA-P, wet weight and protein content ( P <0.02). The losses apparently occurred in the cytoplasmic portion of the muscle fiber. However, this loss was not revealed histologically in the cross section of the muscle fiber. Expression of the results on the basis of unit protein, nitrogen or RNA-P did not significantly alter the results.
Tissue pressure and critical closing pressure in the isolated denervated dog foreleg
Authors: Hinshaw Lerner B. , Day Stacey B.
Published: December 2017

Experiments designed to obtain very low pressures and flows in the isolated leg were performed on the weighed, denervated dog foreleg perfused with homologous blood. Continuous strain gauge recordings of pressure decay curves and rates of weight loss (venous outflow) were obtained after arrest of the arterial inflow. In some instances tissue pressures were measured by a ‘null-point’ procedure. The results provide no evidence for a generalized critical closing pressure in the denervated, blood-perfused, nonedematous leg. After occlusion of arterial inflow the arteriovenous pressure difference fell to zero (0.0 mm Hg) as venous outflow approached zero. Evidence was obtained showing that if a pressure difference is found at zero flow in the isolated leg, it is produced by the existing tissue pressure. An elevated closing pressure is readily obtained in the dog foreleg when the tissue pressure is increased, and its magnitude is directly related to the extent of tissue edema.
Pressor effect of subcutaneous renin in dogs, and effect of reserpine, l-hydrazinophthalazine and hexamethonium on renin hypertension
Authors: Haynes Florence W. , Dexter Lewis
Published: December 2017

The pressor effect of series of subcutaneous injections of hog renin was studied in the dog, as well as the modification of the pressor effects of renin by reserpine, hydralazine ( l-hydrazinophthalazine) and hexamethonium. In 22 of 27 experiments, short series of subcutaneous renin injections (1–37 days) in doses of 550–1800 cat units/day were repeatedly followed by moderate elevations of systolic and diastolic blood pressure, whereas control injections of saline, ACTH or extracts of liver were without effect on the blood pressure. In a number of instances, but not in all, a definite increase in plasma renin could be demonstrated during the pressor effect of renin. The pressor effect of subcutaneous renin was still observed during oral administration of reserpine (0.25 mg/day) and hexamethonium (250–500 mg/day) but was often absent during the administration of hydralazine (25 mg/day). The pressor response to intravenous renin was increased in animals receiving reserpine and hexamethonium and decreased after hydralazine. In vitro experiments with these three drugs failed to indicate any significant effect on the formation or destruction of hypertensin.
Influence of long-term exposure to adverse environments on organ weights and histology
Authors: Hale Henry B. , Mefferd Roy B. , Vawter Gordon , Foerster G. Elizabeth , Criscuolo Dominic
Published: December 2017

A comparison was made of the morphological effects of cold, heat and simulated altitude on adult male rats given exposures of 24 weeks' duration. By the use of covariance analysis it was possible to determine the extent to which organ weights were dependent upon body weight and to adjust the values in order to remove body weight influences. For liver, heart and kidney, adjusted weights indicated temperature-dependency, while pressure-dependency was established for liver and kidney only. Histologically, temperature-dependency was indicated for liver, kidney, thyroid, adrenal and pituitary. Fur weight was reduced in heat but not altered in cold. Fasting in cold induced changes in adrenal and thymus weight and unusually high body weight loss; in heat, fasting caused a significant thymus weight loss without adrenal weight increase. The thymus-adrenal ratio was elevated during a 24-hour fast in all environments except cold, where it was decreased.
Renal excretion of phosphate following parathyroidectomy in the dog
Authors: Foulks James G. , Perry Florence A.
Published: December 2017

The renal excretion of inorganic phosphate in intact and in parathyroidectomized dogs was compared using several procedures for varying the filtered phosphate load. Parathyroid deficiency did not consistently modify the adjustment of renal tubular phosphate transport in response to fasting or to phosphate administration. Parathyroid hormone apparently is not involved in the mediation of these adjustments in tubular phosphate transport. Renal retention of phosphate does not appear to be responsible for the fasting hyperphosphatemia which accompanies parathyroid deficiency. Altered removal of inorganic phosphate from the extracellular fluid, presumably by the cells of soft tissues, offers a more reasonable explanation for the elevation in serum phosphate concentration after parathyroidectomy. However, parathyroid deficiency does not modify cellular uptake of phosphate following insulin and glucose administration.
Hydropenia in cat and dog. Ability of the cat to meet its water requirements solely from a diet of fish or meat
Authors: Prentiss Phoebe G. , Wolf A. V. , Eddy Hubert A.
Published: December 2017

The physiology of hydropenia was studied in cats and dogs placed on three regimens: 1) no water—no food; 2) water ad libitum—no food; and 3) no water—food. Animals deprived of water and food show elevations in plasma sodium, chloride, osmotic pressure and total solids, with progressive hydropenia. Tap water ad libitum prevents these changes in fasting and promotes slight decreases in plasma osmotic pressure; it also sustains life well beyond the period endured by animals with no access to fluid. That cats with no drinking fluid are able to maintain themselves well for long or indefinite periods on diets of cod, salmon and beefsteak, and are unable to do so on partly desiccated salmon and beef, is generally predictable by metabolic calculations and confirmed by measurements. The significance of these facts for the water metabolism of marine mammals which may not drink is broached.
Potability of sea water with special reference to the cat
Authors: Wolf A. V. , Prentiss Phoebe G. , Douglas Lillian G. , Swett Russell J.
Published: December 2017

Under certain conditions in which food provides an adequate caloric intake but too little water to sustain a cat or a rat in euhydration, these animals can be shown to depend for survival on their intake of sea water. They will generally drink enough sea water ad libitum to thrive, even overcoming thereby a previously induced water deficit; or, they will readily eat their food, mixed with sea water in amounts which can vary widely, with similar benefit. Without sea water they undergo progressive hydropenia and die. Along with experimental verification of the potability of sea water a theory of sea water drinking (mariposia) is presented, based upon the concept of urinary osmotic space.
Effects of short changes of environmental temperature and low atmospheric pressure on the ovulation of rats
Authors: Chang M. C. , Fernandez-Cano L.
Published: December 2017

In order to elucidate the external and internal factors that may effect the occurrence of ovulation, white rats were exposed to a higher (103 ± 1°F) or to a lower (26 ± 1°F) environmental temperature, or to a low atmospheric pressure (410 cm Hg) for 5 hours a day on 2 consecutive days. When the animals were caged with fertile males soon after such exposures it was found that estrus and ovulation was inhibited significantly for a period of two normal estrous cycles. The number of subsequent ovulations, the maintenance of pregnancy and the development of embryos, however were not affected. This inhibition is discussed in the light of a shift from gonadotropic hormone secretion to ACTH secretion in the anterior pituitary gland following a stressful condition.
Functional reactivation of the hypothermic heart after potassium arrest
Authors: O'Brien Larry J. , Guest M. Mason
Published: December 2017

Myocardial function in the dog heart-lung preparation was studied during essentially normothermic conditions and during hypothermia. With the circulating blood at between 26 and 28°C. ventricular fibrillation produced by faradic stimulation of the left ventricle was arrested by the retrograde injection of 2% potassium chloride. The administration of 50% fructose was found to be a highly effective means of reducing the circulating potassium levels and reestablishing normal cardiac irritability. Large amounts of potassium and glycogen were deposited in the myocardium. No gross indications of impairment were observed in the restored cardiac function as a result of fibrillation, arrest, or the transient alterations in potassium and fructose concentrations.
Hypothermia: alterations in cardiac and skeletal muscle electrolytes
Authors: Beavers W. Robert , Rogers J. T.
Published: December 2017

Analyses of sodium, potassium, chloride and water of cardiac and skeletal muscle were made in normal dogs, in animals cooled to rectal temperatures of 20°C, and in cooled animals receiving 25% glucose intravenously. Using these data and determinations of plasma electrolytes, muscle intracellular water was calculated. An increase in cardiac muscle potassium and in calculated intracellular water of both cardiac and skeletal muscle was noted in the cooled animals. Administering hypertonic glucose during cooling increased cardiac muscle potassium to even higher levels and calculated intracellular water of cardiac and skeletal muscle was similar to normal values.
Determination of rate of cross circulation in parabiotic rats with P32-labeled erythrocytes
Authors: Fleming David G. , Caldwell Laura , Jacobs Roberta
Published: December 2017

Litter-mate female rats parabiosed at 21 days by the Bunster-Meyer method were allowed to mature for several months. Volumes of blood obtained from donor animals were incubated at 37°C with P32, in the form of buffered isotonic sodium phosphate. A plasma-free suspension of labeled erythrocytes was prepared and a sample of known activity was injected into the femoral vein of one member of each parabiotic pair. Four pairs of 100 lambda blood samples, obtained by venipuncture, were taken at varying intervals, for the succeeding 150 minutes. Using the dye dilution principle, it was possible to determine the blood volume of the injected rat after the first sample, and that of the pair at the time of equilibrium. The average blood volume was 6.53% of body weight. The concentration of tagged cells reached equal values in both members of the pairs at an average time of 90 minutes. There was less than a 20% loss of total activity in all the pairs used for determinations. An equation was derived for the calculation of the rate of exchange. The average for 15 pairs was 2.09 blood volumes per hour. The range was from 3.95 bl. vol/hr. in the fastest pair to 0.74 bl. vol/hr. in the slowest.
Correlation of carotid blood pressure and isometric muscle tone under variable conditions
Authors: Hicks James Thomas , Leese Chester Elwood
Published: December 2017

A correlation between normal carotid blood pressure and isometric muscle tone over a 2-minute period of artificial stimulation was established. The blood pressure was lowered with histamine and Mecholyl with the correlation noted along with a decrease in muscle tone. The blood pressure was raised with epinephrine and Pitressin with the correlation noted along with an increase in muscle tone. All results were subjected to statistical analysis with significant results noted. No difference was noted between decerebrate and animals under sodium pentobarbital anesthesia.
Effects of an antihypertensive drug, pentolinium
Authors: Haas E. , Goldblatt H.
Published: December 2017

The action of pentolinium and of eight pressor agents, alone and in combination, on the blood pressure and pulse rate of normal, unanesthetized dogs was investigated. The slow, continuous infusion of the ganglionic blocking agent induced reactions considerably different from those of other investigators who administered single massive doses to animals subjected to anesthesia or to various surgical procedures. To elucidate the mechanism of the well known potentiation of pressor agents by ganglionic blocking agents, the effects were investigated of simultaneous ganglionic and adrenergic blockade, of acetylcholine and atropine and of nicotine and other ganglionic stimulating agents. The results of some of these experiments are at variance with previous concepts, and it appears that the potentiation phenomenon can be ascribed neither to a release of sympathomimetic amines nor to a blockade of compensatory, autonomic buffer reflexes by pentolinium. An alternate explanation is that pentolinium may be competing with the continuous ‘background’ dilating action of intrinsically liberated acetylcholine in the wall of the arterioles, thus inducing an increased responsiveness of these vessels to vasoconstriction.
Bone marrow function in perfused isolated hind legs of rats
Authors: Kuna Samuel , Gordon Albert S. , Morse Bernard S. , Lane Francis B. , Charipper Harry A.
Published: December 2017

Successful use has been made of a perfusion technique in the study of bone marrow in isolated hind legs of rats. With this method, legs of rats were perfused for a period of 4 hours without showing signs of rigor or edema. Except for a rise in inorganic phosphate in the perfusate, the physiologic, pharmacologic and biochemical aspects of the perfusate and marrow were essentially normal throughout the experimental period. The femoral marrows within isolated legs of rats showed significant increases in the nucleated red blood cell numbers when perfused with whole blood obtained from rats subjected to a) low barometric pressures, b) hemorrhage or c) phenylhydrazine treatment, thus indicating a direct action of the circulating ESF on the blood-forming tissues. Stimulatory effects upon erythropoiesis were also observed in legs of vitamin B12-deficient rats perfused with whole blood and in legs perfused with blood containing aminopterin.
Influence of the adrenal gland on hypothermic response of the rat to chlorpromazine, reserpine and serotonin
Authors: Hoffman Roger A.
Published: December 2017

This study was made to determine the influence of the adrenal gland on the temperature response of the rat to chlorpromazine, reserpine and serotonin. It was found that endogenous epinephrine does not enter into the thermoregulatory response to chlorpromazine. While the cortical factors do not prevent a hypothermia, they do inhibit this response from reaching excessive levels and in time permit a complete recovery. Both epinephrine and the cortical factors, however, play a role in the temperature response to serotonin and reserpine. The data indicate that either epinephrine or serotonin alone can cause a marked hypothermia. Injected together, however, a mutual antagonism is evident and the hypothermic response is inhibited or delayed. While the cortical factors are sufficient to prevent excessive hypothermia and mortality of serotonin-treated rats, these plus epinephrine are necessary to assure survival in the reserpine-treated animal. The data emphasize the marked influence which epinephrine might exert on other serotonin or reserpine-induced responses.
Effects of prenatal X-irradiation on testicular function and morphology in the rat
Authors: Ershoff Benjamin H.
Published: December 2017

Present findings confirm and extend previous observations that x-irradiation during certain stages of prenatal development results in testicular injury and infertility in the male rat. The effects were particularly marked in the offspring of rats irradiated on the 18th day of pregnancy. These rats also showed in addition to testes injury a significant reduction in seminal vesicle weight. Testicular injury also occurred in the offspring of rats irradiated on the 14th day of pregnancy but was less marked than in the 18-day series. No abnormalities in testicular function or morphology were observed in the offspring of rats irradiated on the 10th day of pregnancy.
An analysis of the metabolic responses of rats exposed to cold
Authors: Weiss A. Kurt
Published: December 2017

When young Holtzman rats (150 gm) were exposed to +5 ± 2°C for 10 days their metabolic rate (measured at 28°C) was elevated. Injection of sodium pentobarbital (30 mg/kg, i.p.) just prior to the metabolism determination lowered the metabolic rate of both control and cold-exposed animals, but did not alter the general pattern of the cold-induced elevation of the metabolic rate, so that the metabolism of the rats exposed to cold was still higher than that of the controls. When older rats (300 gm and more) were exposed to –5 ± 2°C for up to 10 days, the metabolic rate of the survivors was elevated also. In these animals, however, sodium pentobarbital administration lowered the metabolic rate of the cold-exposed animals to about the same level as that of the controls. This indicates that the older rats exposed to –5°C achieve protection against the cold environment primarily through changes which may be of neurogenic origin.
Inactivation of serum ribonuclease by the kidney
Authors: Dohi S. R. , Terzian J. F. , Widman A. , Brentani R. , Fausto N. , Liberman B. , Rabinovitch M.
Published: December 2017

The ureterovenous anastomosis preparation (U.V.A.) was used to study the inactivation of serum ribonuclease (RNase) by the kidneys. A significant increase was found in the enzyme activity 2 hours after the operation, with a return to levels close to the initial ones in succeeding periods up to 8 hours. This behavior contrasted with that of bilaterally nephrectomized dogs where activity steeply rose to high levels and was thereafter maintained. The behavior of serum creatinine was similar in both groups of animals. Infusion of urine did not influence the RNase activity increase of nephrectomized dogs. U.V.A. animals, when nephrectomized, were able to respond with increases in serum RNase. Athrocytosis of intravenously injected hemoglobin was observed in U.V.A. dogs. It is suggested that these findings agree with the hypothesis of a mechanism of glomerular filtration plus tubular reabsorption and destruction of part of the plasma RNase.
Strength-duration curves in the hypothermic dog heart
Authors: Torres J. C. , Angelakos E. T. , Hegnauer A. H.
Published: December 2017

Strength-duration curves were constructed from threshold measurements obtained with unipolar anodal and cathodal stimuli at various temperatures. Stimuli ranging in duration from .1 to 50 msec. were delivered during diastole via an electrode sutured to the left ventricular surface. Thresholds were measured at 37°, 29°, 23° and 19°C. Plotting thresholds against reciprocal of stimulus duration it was possible to transform the strength-duration curves into straight lines. All lines demonstrated a progressive increase in slope with low temperatures, the increase being greater for the anodal strength-duration lines. The changes in chronaxie were secondary to the slight changes in rheobase and the more important increases in slope of the strength-duration lines. It is concluded that cold causes a decrease in excitability to stimuli of short duration, this effect being greater for anodal than for cathodal stimuli.
Relative importance of venous and arterial resistances in controlling venous return and cardiac output
Authors: Guyton Arthur C. , Abernathy Berry , Langston Jimmy B. , Kaufmann Berwind N. , Fairchild Hilton M.
Published: December 2017

In dogs with cardiovascular reflexes completely blocked by total spinal anesthesia, the total peripheral resistance was increased five- or more fold in two ways: first, by injecting small plastic microspheres into the arteries, thereby increasing the arterial resistance, and, second, by inflating pneumatic cuffs around the major veins, thereby increasing venous resistance. A small increase in venous resistance decreased cardiac output eight times as much as an increase in arterial resistance of similar magnitude. This difference was caused principally by a) a marked rise in systemic arterial pressure when arterial resistance was increased; this maintained the cardiac output at almost normal levels and b) a fall in systemic arterial pressure when venous resistance was increased; this promoted even more fall in cardiac output than increased total peripheral resistance alone would have caused.
Effects of menadione on active sodium transport in isolated frog skin
Authors: Wang Dah-Hsi , Koblick Daniel C.
Published: December 2017

The effects of menadione (2-methyl-1, 4-naphthoquinone), a potent inhibitor of choline acetylase, were studied. It was found that a 4 x 10–5 m solution of the inhibitor causes a transient increase in short-circuit current and trans-skin potential followed by an exponential decrease in both variables. This pattern is observed on application of the inhibitor to either epidermal or dermal surface. Epidermal treatments are more effective as judged by the lag time of the decay phase.
Effect of nephrectomy on the minute renal circulation
Authors: Hartman Mary Ellen , Bonfilio Antoinette C.
Published: December 2017

By means of a technique determining the number of glomeruli patent to plasma flow in a 10-second interval it was established that unilateral nephrectomy was followed by a rise in glomerular count both immediately and 4–7 days after nephrectomy in the 50–125-gm animal. The glomerular count was greater in the 4–7-day postnephrectomy group. The 126–200-gm animals had no immediate response to nephrectomy but showed a rise in count in the 4–7-day postnephrectomy period. It is therefore inferred that under the stated experimental conditions in the normal animal all the glomeruli are not patent to the flow of plasma at any one time.
Renal tubular transport of Diodrast-I131 and PAH in Necturus: evidence for simultaneous reabsorption and secretion
Authors: Kinter William B.
Published: December 2017

Renal plasma clearances were determined in pithed Necturi from samples of cloacal urine and branchial arterial blood. Simultaneous clearance of creatinine and inulin carboxylic acid-C14 corresponded closely. Diodrast-I131 and/or para-aminohippurate (PAH) clearances were less than simultaneous creatinine clearances in about 80% of the Necturi. At low plasma concentrations of Diodrast and/or PAH, Diodrast/ creatinine and/or PAH/creatinine clearance ratios were independent of concentration and exhibited a seasonal variation, approximating 0.2 in ‘winter’ and 0.5 in ‘summer.’ In a random 20% of the animals, however, ratios were greater than unity, approximating 2.0. In both groups of animals the ratios generally approached unity at high plasma concentrations. However, under the conditions of high PAH and low Diodrast concentrations in the group with initial ratios less than unity, the Diodrast ratio approximated 2.0. These data are interpreted as evidence that in Necturus kidney over-all tubular transport of Diodrast and PAH is the net result of simultaneous reabsorption out of and secretion into tubular urine.
Gamma irradiation on rat whole blood cholinesterase
Authors: Williams Martin W.
Published: December 2017

Rat whole blood cholinesterase levels were followed electrometrically for 10 days following whole-body irradiation with 300 and 600 r gamma rays from a Co60 source. Cholinesterase activity was significantly depressed in both groups after the 3rd day, reaching its lowest observed levels on the 10th day. The toxicity of acetylcholine bromide was significantly greater to mice 9 days after 300 r of whole-body gamma irradiation than in nonirradiated controls as indicated by the intraperitoneal ld50 which was 294 mg/kg prior to, and 235 mg/kg after, irradiation.
Experimental modifications and changes with age in pineal succinic dehydrogenase activity
Authors: Quay W. B.
Published: December 2017

Pineal succinic dehydrogenase was determined by means of reduction of 2,3,5-triphenyl-2H-tetrazolium chloride and colorimetry. Studies employing over 3300 rats, primarily of the Long-Evans strain, demonstrate that: a) Al+++ and Ca++ promote and Cu++, malonate, iodine and hydroquinone inhibit enzyme activity in vitro; b) enzyme activity more than doubles in both sexes during the first 6 weeks postnatally with some reduction probable in about 1 year; c) pineal activity equals 50% of that of liver, 75% of tela chorioidea IV, 90% of cerebral cortex (area 18) and 160% of hypophyseal posterior lobe; d) norepinephrine or DOPA injection is usually followed (1–8 hours) by increased pineal activity; e) Dibenamine alone may depress activity after 18–19 hours but when followed by norepinephrine, DOPA, epinephrine, ephedrine, amphetamine or serotonin (4–6 hr. before autopsy) potentiates increased activity; f) Marsilid alone may stimulate activity (18 1/2–20 hr.) but when followed by norepinephrine, or DOPA potentiates decreased activity; g) extensive negative results with modifications in thyroid, adrenal cortical and gonadal endocrines do not support beliefs in pineal regulation by these pituitary-dependent systems. The hypothesis is advanced that the mammalian pineal is functionally involved with central mechanisms concerned with the metabolism and/or actions of certain neurohumoral amines.
Changes in body composition attendant on force feeding
Authors: Cohn Clarence , Joseph Dorothy
Published: December 2017

Normal young adult male rats were either force-fed or allowed to eat ad libitum a moderate carbohydrate diet for 3–4 weeks. The force-fed animals were given either the amount of diet consumed by the animals eating ad libitum (pair-fed) or 80% of this amount (underfed). After a 2-week period of observation, we found that the rats eating ad libitum gained 65 gm of body weight, the pair-fed, force-fed 62 gm and the underfed, force-fed 40 gm. On the basis of the water, fat and protein content of the skin, viscera and carcass of control animals killed at the beginning of the feeding regimen and of similar constituents of the experimental animals after 2 weeks of feeding, the composition of the newly formed tissues of the various groups of animals consisted of the following: a) the rat with free access to food—water = 67.8%, fat = 7.8% and protein = 22.4%; b) the pair-fed, force-fed animal—water = 55.5%, fat = 23.6% and protein = 17.7%; c) the underfed, force-fed animal—water = 64.4%, fat = 7.9% and protein = 20.0%. The ratio of calories retained in newly formed tissue to the calories ingested over the 2-week period was 11.9% for the animals eating ad libitum, 20.6% for the pair-fed, force-fed animals and 9.5% for the underfed, force-fed rats. Force feeding appears to change intermediary metabolic pathways in the direction of increased ‘efficiency’ with resultant greater fat deposition.
Gastric distensibility and age in the mouse
Authors: McArthur W. , Ogawa T. , Necheles H.
Published: December 2017

Gastric distention and age appear to play a role in ulcer formation in the pylorus-ligated mouse. For this reason, distensibility of the stomach of albino Swiss male Rockland R. A. P. mice was investigated. The excised stomach was ligated at the pylorus and saline was injected slowly through a tube in the esophagus. Pressure and maximum volume of saline used to reach the breaking point were determined. Most perforations occurred in the glandular stomach. Gastric perforations in young mice were produced with considerably less pressure and smaller volumes of saline than in older animals. These results may explain previous observations on age differences in ulcer formation and mechanical gastric perforation in the pylorus-ligated mouse. A possible relation between intragastric pressure, circulation and ulceration, is discussed.
Action of acetylcholine, choline and D-tubocurarine on the membrane of frog sartorius muscle fibers
Authors: Ochs S. , Mukherjee A. K.
Published: December 2017

Resting potentials of frog sartorius muscle fibers were taken with microelectrodes at different distances along the length of muscles before and after adding acetylcholine or choline. The mean membrane potential drop and scatter of the potentials recorded in the relatively nerve-free, and in the more densely innervated parts of the muscle, were similar. The loss of direct excitability to electrical and mechanical stimulation was correlated with the concentration of choline or acetylcholine presented. d-tubocurarine added beforehand protected against the depolarizing effect of acetylcholine and choline everywhere along the length of the muscle. A generalized action of acetylcholine and choline and also of d-tubocurarine all along the muscle fibers was inferred. This generalized action at higher concentrations of acetylcholine and choline is believed to be additional to a more specific end plate action.
Anti-inflammatory activity of some water-soluble bioflavonoids
Authors: Menkin Valy
Published: December 2017

The water-soluble citrus bioflavonoid mixture contained in the preparation C.V.P., without added vitamin C, is capable of inhibiting the increased capillary permeability referable in turn to an inflammatory exudate, irrespective of the pH of that exudate. The suppressing effect of these water-soluble bioflavonoids can be demonstrated in concentrations of 5 or 10 mg/0.25 ml of exudative material. They likewise inhibit the effect of leukotaxine that has been extracted from alkaline exudates. In this way they repress not only increased permeability of capillaries, but also the local emigration of leucocytes. Finally this water-soluble bioflavonoid mixture appears to behave as an anti-inflammatory agent over a larger pH range of exudates than either cortisone or corticotropin, (ACTH). Cortisone represses permeability increase and leucocytic migration of alkaline exudate. ACTH suppresses the activity of exudin in its ability to increase local capillary permeability induced by acid exudates. This bioflavonoid mixture is capable of inhibiting in this regard both alkaline and acid exudates. The possible potentials of C.V.P. are pointed out.
Inhibition of gastric secretion by thyroid preparations
Authors: Nasset E. S. , Logan V. W. , Kelley M. L. , Thomas Mary
Published: December 2017

Four dogs with Thomas gastric pouches and one dog with a Heidenhain pouch were stimulated to secrete gastric juice by feeding 100 gm of lean beef. Feeding whole desiccated thyroid ordinarily caused a significant fall in volume of gastric juice and in the total quantity of HCl secreted. Crystalline thyroxine yielded erratic results and one trial with triiodothyronine produced a significant increase in gastric secretion. Thyroidectomy in one dog resulted in a gradual decline in secretion, but hypothyroidism produced by administration of mercaptoimidazole in another animal lead to a significant increase in secretion.
Simultaneous flux of potassium into and out of the dog intestine
Authors: Berger Eugene Y. , Kanzaki Grace , Steele J. Murray
Published: December 2017

Potassium moves across the intestinal mucosa from the lumenal surface to the blood simultaneously with a stream in the opposite direction from blood to lumen. The net result of these two flows determines the amount of potassium appearing in the intestinal lumen. These two flows were measured across isolated loops of intestine in the dog with the use of radiopotassium. For a 20-cm length of intestine, potassium enters the lumen at 0.8–6.5 µEq/min., and simultaneously leaves the lumen at 0.7–5.2 µEq/min.
Effect of ß-sitosterol on serum cholesterol concentration in the rat
Authors: Nath Narindar , Harper A. E.
Published: December 2017

ß-Sitosterol added to a diet containing cholesterol alone or with cholic acid, diminished the accumulation of serum and liver cholesterol in the rat. This effect depended upon the quantity of ß-sitosterol added. Addition of ß-sitosterol to a diet containing corn oil enhanced the hypocholesteremic effect of corn oil. Calciferol and Q275 when fed to rats had no significant effect on serum cholesterol concentration, but calciferol caused an increase in the deposition of cholesterol in the liver.
Body composition and in vitro synthesis of lipids by adipose tissue of 11-dehydrocorticosterone-treated mice
Authors: Hollifield Guy , Parson William
Published: December 2017

Compound A (11-dehydrocorticosterone) pellets implanted subcutaneously produced increased carcass fat and decreased protein in older mice but not in young mice of the DBA strain. The increased carcass fat is not the result of increased food intake or weight gain since it occurs in the face of a decreased food intake and weight loss and is associated with a decrease in spontaneous running activity. Adipose tissue of mice treated with compound A pellet implants has a greater lipid synthesis from C14-labeled acetate than that from cholesterol-treated controls. These findings lend support to the idea that compound A causes increased gluconeogenesis and increased insulin production with a resultant stimulation of fat synthesis by adipose tissue.
Effect of carbon tetrachloride poisoning on potassium, sodium and water content of liver mitochondria
Authors: Share Leonard , Recknagel Richard O.
Published: December 2017

A physiological test of mitochondrial function, which measures the ability of the mitochondria to concentrate potassium in vitro, was employed in a study of carbon tetrachloride-induced hepatotoxicity. The force feeding of carbon tetrachloride resulted in a) a reduction in the potassium content of rat liver mitochondria, b) an impairment in the ability of potassium depleted mitochondria to reaccumulate potassium and c) an increased water content of the mitochondria. The changes could be demonstrated unequivocally at 10.5 hr. and became extensive at 20 hr. The results do not support the view that the increase in liver fat is the direct result of a lesion in the mitochondria since the time course of impairment in mitochondrial potassium and water metabolism lags behind the fatty changes of the whole liver.
Excitability changes in vasomotor areas of the brain stem following D-tubocurarine
Authors: Peiss Clarence N. , Manning John W.
Published: December 2017

Cardiovascular responses to electrical stimulation of the medulla and hypothalamus have been studied before and after administration of d-tubocurarine. The drug was administered intravenously (100–150 gamma/kg) intracarotid (100–150 gamma/kg) and by direct microinjection into the medullary vasomotor area (3–15 gamma total dose). The possibility of autonomic ganglia or effector blockade was ruled out. Excitability of the medullary vasomotor area to electrical stimulation was depressed following injection of d-tubocurarine by any of the three routes. Partial to total elimination of pressor responses has been observed, as well as reversal from a pressor to a depressor response. Cardiac slowing resulting from stimulation of the dorsal vagal nucleus is abolished or greatly decreased by intracarotid injection of 150 gamma/kg of d-tubocurarine. Doses of this drug which depress the medulla had relatively little effect on similar cardiovascular responses elicited by stimulation of the hypothalamus.