bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Experimental Hypertension and of Aging on the Spontaneous Running Activity of Rats
Authors: Fregly Melvin J. , Cook Cynthia S.
Published: December 2017

Under conditions of constant temperature at 25°C and controlled illumination, the spontaneous running activities of separate groups of experimentally hypertensive rats were measured at graded periods of time after bilateral kidney encapsulation. The activity of hypertensive rats was greater than that of controls from 3–8 weeks after kidney encapsulation; i.e., during the time blood pressure was increasing. When blood pressure became maximally elevated (8–9 weeks after kidney encapsulation), activity of hypertensive rats decreased to that of control rats and thereafter the activities of both groups decreased in the same fashion with increasing age. Under these conditions hypertensive disease did not impose a limitation on spontaneous activity despite the increased work load of the heart and the elevated mean blood pressure. Comparable results were also observed when hypertensive and normal rats were kept continuously in activity cages. Unrestricted activity did not affect either the time course of development or the severity of the elevated blood pressure.
Effect of Hyper- and Hypothyroidism on Intestinal Absorption of Cholesterol in Rats
Authors: Rosenman Ray H. , Friedman Meyer
Published: December 2017

Thoracic duct lymph was collected from normal and hyper- and hypothyroid rats following administration of a test dose of cholesterol dissolved in olive oil. The data indicate that such deranged thyroid function does not significantly alter the intestinal absorption of cholesterol.
Basic Oscillating Mechanism of Cheyne-Stokes Breathing
Authors: Guyton Arthur C. , Crowell Jack W. , Moore John W.
Published: December 2017

Cheyne-Stokes breathing has been induced in 30 dogs by inserting a circulatory delay system between the heart and the brain to prolong the transit time of blood from the lungs to the brain. The duration of each cycle of Cheyne-Stokes breathing increased proportionately with the volume of the delay system and decreased as the perfusion pressure to the brain was increased. Periodic variations in oxygen and carbon dioxide concentrations in the blood were found to be in appropriate phase to stimulate the respiratory centers at the time of maximal ventilation. This supports the theory that Cheyne-Stokes breathing is due to oscillation of the respiratory control system.
Acute Dynamic Effects of a Shunt Between a Systemic Artery and the Left Atrium
Authors: Rodbard S. , Krause S. , Lowenthal M. , Katz L. N.
Published: December 2017

A communication was established between the left subclavian artery and left atrium in dogs to assess the acute dynamic effects of a diastolic input load on the left heart. Sudden diastolic pressure loading, produced by opening the shunt abruptly was followed by acute ventricular dilatation and fibrillation, and pulmonary congestion and edema. Gradual opening of the shunt provided time for cardiac adjustments to the increased ventricular output, and acute failure did not occur. These data suggest that adjustments in myocardial function can take place quickly in response to a markedly enhanced input load. On opening the shunt the aortic pressure fell in consonance with the decreased total peripheral resistance, while the left atrial pressure increased sharply. The pulmonary arterial pressure remained unchanged. Systemic vasoconstriction produced by adrenalin, strophanthin or asphyxia enhanced the flow through the shunt.
Thoracic Duct Lymph and Lymphocytes in the Guinea Pig
Authors: Reinhardt W. O. , Yoffey J. M.
Published: December 2017

The guinea pig is a suitable animal for the collection of thoracic and cervical duct lymph. Values have been ascertained for lymph flow and lymphocyte output in the anesthetized male guinea pig under various experimental conditions. Evidence is presented which suggests the existence of a diurnal rhythm in level of thoracic duct output of lymphocytes. Effects of fasting and of hypoxia have been observed as examples of stimuli operating within a physiological range. Effects of interventions such as evisceration, biliary obstruction and fistulation, and treatment with adrenaline have also been observed. As compared with normal values, hypoxia was found to be an adequate stimulus to produce an increase in lymph flow and lymphocyte output. Fasting and treatment with adrenaline produced decreased lymphocyte output by the thoracic duct. Evidence provided by study after evisceration suggests that about 95% of the cells in the thoracic duct are derived from the lymphatic tissues associated with the gastroenteric tract and related tissues, residual thoracic duct lymph flow after evisceration being of the same order of magnitude as for the cervical lymph ducts. Obstruction of the common bile duct increased thoracic duct lymph flow as compared with the decrease produced by biliary fistulation. Removal of the thymus was associated with a marked decrease in the output of thoracic duct lymphocytes in both normal and splenectomized guinea pigs. Splenectomy was not associated with such a decrease in thoracic duct lymphocyte output.
Influence of Decreased Ambient Oxygen on Susceptibility of Rats to Audiogenic Seizures
Authors: Mitchell Walter G. , Hitchcock Fred A.
Published: December 2017

Male Wistar rats were tested for audiogenic seizure susceptibility at various levels of decreased ambient oxygen. At 15.9% and 12.3% oxygen, the number of seizures occurring were approximately the same as the controls. Enhancement of seizure susceptibility occurred at 14.5% ambient oxygen, indicating a preliminary excitatory effect. Oxygen levels of 9.6% and below resulted in inhibition of seizures. The over-all picture was that of a biphasic effect of oxygen lack on audiogenic seizure susceptibility.
Blood Oxygen Capacity of Albino Rats
Authors: Burke Jack D.
Published: December 2017

The oxygen capacity of the blood of 64 albino Rattus norvegicus (Sherman strain) was determined by the microgasometric syringe method. Data were obtained showing the relationship of blood oxygen capacity to weight and sex of the animals. It was found that blood oxygen capacity in volumes per cent increased as the weight of the rats increased. Statistically, there was no difference in the blood values in either male or female rats as analyzed in different weight groups and ranges. Also, the oxygen capacity of the blood per unit of body weight decreased as the weight of the rats increased.
Heparin Content of Thoracic Duct Lymph Following Shock in Dogs
Authors: White Richard P. , Woodard Parke H.
Published: December 2017

Anaphylactic or peptone shock causes a release of heparin which is present in greater concentrations in lymph obtained from the thoracic duct than in either arterial or hepatic venous blood. Frequently heparin is present only in thoracic duct lymph following such shock. The evidence indicates that the source of this heparin is the liver and that during shock its passage from liver to blood is mainly by means of the thoracic duct. Heparin is not released into thoracic duct lymph or blood during a histamine or hemorrhage induced shock.
Effects of Prolonged Optic Nerve Tetanization on Lateral Geniculate Potentials
Authors: Evarts Edward V. , Hughes John R.
Published: December 2017

Tetanization of the optic nerve at 500/sec. for periods varying from 5 seconds to 6 minutes produced a long lasting (hours) second subnormality of the postsynaptic lateral geniculate response in nembutalized cats. Optic nerve tetanization for 10 minutes or longer did not produce a second subnormality. When such a prolonged tetanus was applied during previously induced second subnormality, this subnormality was abolished. Tetanization for 10 minutes or longer did not prevent the occurrence of second subnormality produced by a subsequently applied shorter (0.5 min.) tetanus. Second subnormality did not occur following tetanization of the optic nerve in unanesthetized decerebrate cats. This finding suggests that the metabolic changes associated with Nembutal anesthesia were of importance in the occurrence of second subnormality.
Olfactory Sensitivity in the Domestic Pigeon
Authors: Calvin Allen D. , Williams Clarence M. , Westmoreland Nelson
Published: December 2017

Olfactory sensitivity in the domestic pigeon was investigated using an instrumental conditioning procedure. The pigeons were trained to move from one section of a compartment to another by using light and odor paired together as the conditioned stimulus with electric shock acting as the unconditioned stimulus. After the pigeons had learned to cross from one section to the other at the presentation of the light and odor together, the light was removed and only the odor presented. The pigeons were unable to learn to use odor acting alone as a cue; thus these findings gave no indication of highly developed olfactory sensitivity in the domestic pigeon.
Interrelation of Insulin Activity and Thyroid Function
Authors: Cohen Aharon M.
Published: December 2017

The effect of variation in thyroid status on insulin metabolism and glycogen synthesis has been studied in rats. In vitro incubation of rat diaphragm with 0.1 mg triiodothyronine or 0.1 mg thyroxine for 30 and 45 minutes had no effect on I131 insulin uptake of the diaphragm. Daily intraperitoneal injections of 50 γ triiodothyronine increased the oxygen consumption and had an increasing effect on in vitro insulin diaphragm uptake, beginning after 2 days, reaching a maximum of 32% over controls on the 5th day. With continued administration of triiodothyronine diaphragm insulin uptake declined to control levels on the twelfth day of triiodothyronine administration. During the first 2 minutes after intravenous administration of I131 insulin in triiodothyronine treated animals (50 γ daily, i.p. for 5 days) muscle showed an increased uptake of insulin. There was a subsequent progressive fall in tissue uptake to approximately levels found in control animals. Blood radioactivity disappeared more rapidly after injection in the thyrotoxic animal than in the control or hypothyroid rats. Glycogen deposition (insulin-glycogen effect) in the thyrotoxic animals was greater than in controls. However, while tissues from control animals continued to deposit glycogen at the same rate, the diaphragm from thyrotoxic rats showed after 30 minutes of incubation a marked fall in glycogen synthesis. Glycogen synthesis by diaphragm from triiodothyronine treated animals incubated in glucose alone without insulin equilibration was the same as control diaphragm.
Effects of Hyper- and Hypothyroidism on Hepatic Lymph Cholesterol in Rats
Authors: Friedman Meyer , Rosenman Ray H.
Published: December 2017

Hepatic lymph was obtained from normal, and hyper- and hypothyroid rats and analyzed for its content of cholesterol and total lipid. The hyperthyroid rat exhibited an increased volume flow of hepatic lymph with normal lymph cholesterol concentration, and the hypothyroid rat a normal volume flow of lymph but with an increased concentration of lymph cholesterol. The data indicate that the rise of plasma cholesterol occurring in the hypothyroid state cannot be ascribed to any decrease in its ability to diffuse passively out of the plasma.
Factors Facilitating Cholesterol Absorption From the Intestine Via Lymphatic Pathways
Authors: Vahouny George V. , Fawal Isa , Treadwell C. R.
Published: December 2017

The lipid fractions of thoracic duct lymph in unanesthetized rats were determined following intragastric administration of saline-albumin emulsions containing various combinations of cholesterol, taurocholate and oleic acid. Sodium taurocholate or oleic acid alone produced significant increases in the total lipid, neutral fat and phospholipid fractions, but had no effect on the level of free and ester cholesterol. Administration of cholesterol alone was without effect on any of the fractions. The combination of taurocholate and oleic acid gave the same levels of lipid fractions as when they were administered singly except that there was an elevation of ester cholesterol indicating increased absorption of endogenous cholesterol. Cholesterol plus taurocholate or oleic acid produced the same increases in the fractions as the salt or acid alone except that with both combinations there were highly significant increases in the total and ester cholesterol fractions. Administration of the three factors together gave further increases in all fractions except neutral fat and free cholesterol. The amount of free cholesterol was constant throughout all groups, even in those in which there was absorption of exogenous cholesterol. The percentage of ester cholesterol in the total cholesterol of lymph ranged from 66 to 81 with the higher percentages in the groups where cholesterol absorption occurred. The esterification of the ‘extra’ cholesterol in lymph due to cholesterol absorption ranged from 86 to 92%. It is suggested that essentially all of the cholesterol transferred from the intestinal lumen to the lacteals is esterified.
Effect of Body Temperature on Pulmonary Gas Exchange
Authors: Otis A. B. , Jude James
Published: December 2017

Measurements were made of the arterial-alveolar carbon dioxide gradient in anesthetized dogs at body temperatures ranging from normal down to 16°C. Pulmonary diffusing capacity was determined by a steady-state carbon monoxide method in anesthetized dogs at normal body temperatures and at 25°C. From the results it is concluded that although diffusing capacity is reduced at low body temperatures, it is still adequate for transfer of both CO2 and O2 because the metabolic requirements for gas exchange are also reduced.
Effect of Pentobarbital Anesthesia on the Blood Values of Rat Organs and Tissues
Authors: Rieke William O. , Everett Newton B.
Published: December 2017

Effect of pentobarbital anesthesia on the erythrocyte, plasma and true blood volumes of organs and tissues of male albino rats has been determined. The isotopic dilution method was applied utilizing Fe59-labeled cells for the red cell determinations and I131 serum albumin for the plasma determinations. Animals were frozen in liquid nitrogen and organs were removed and assayed without blood loss. Redistribution of body blood occurred with anesthesia so that great increases in blood volume and hematocrit were found in splanchnic organs and in the kidney. These changes are discussed in relation to postanesthetic renal and intestinal dysfunction. Pentobarbital decreased significantly the blood volume of central nervous system tissue, of skeletal and cardiac muscle, and of bone. It increased the blood volume of skin and reproductive organs. Respective tissue hematocrit changes were noted and an interpretation of some of the changes is offered. The total body change produced by pentobarbital was an increase in both cellular and plasma constituents of blood in such a ratio that the total body hematocrit fell. The ratio of body hematocrit to venous hematocrit also declined. It is pointed out that these changes may result from an opening of many capillaries allowing low hematocrit blood to enter the general circulation. Passage of tissue fluid into the vascular system may also account for part of the increased total plasma volume.
Stressor Effect of Hypothermia in the Rat
Authors: Fisher Edwin R. , Fedor E. J. , Fisher B.
Published: December 2017

The effect of hypothermia upon the adrenal cortex of the rat was evaluated by comparing the weights, histochemical and morphological appearance and ascorbic acid content of adrenals from cooled animals under ether and Nembutal anesthesia with normothermic controls. Hypothermia with ether narcosis for 2 hours resulted in a statistically significant decrease in adrenal weight related to loss of water and solids. Histologically, a decrease of adrenal cortical sudanophilia and cholesterol and/or esters was noted in approximately one-half of these animals and the ascorbic acid content of these glands was significantly decreased. The adrenals of rats subjected to hypothermia with ether for 6 hours however, were similar to those of normothermic controls. Similarly, short and long term hypothermia with Nembutal anesthesia failed to reveal any alteration in the adrenal cortex. These findings have been interpreted as indicating that in the rat an initial stress is attendant with hypothermia when ether anesthesia is employed.
Lack of Influence of the Sympathetic Nervous System on the Calorigenic Response to Thyroxine
Authors: Surtshin A. , Cordonnier James K. , Lang S.
Published: December 2017

Normal rats as well as thyroparathyroidectomized rats concurrently given thyroxine and an adrenergic blocking dose of Dibenzyline show the expected rise in rate of oxygen consumption. After bilateral adrenal demedullation the resting rate of oxygen consumption is not significantly different from normal, and injection of a large dose of thyroxine either with or without concurrent administration of adrenergic blocking doses of Dibenzyline is followed by a significant rise in the rate of oxygen consumption. Our data and other pertinent published data lend support neither to the claim that the calorigenic effect of exogenous thyroxine is dependent upon the presence of normally acting adrenal medullary hormones nor to the claim that the metabolic changes of thyrotoxicosis are due to the physiological effects of epinephrine and norepinephrine as augmented by the thyroid hormones.
Effect of Adrenalectomy on Production and Excretion of Ammonia by the Kidneys
Authors: Wilson Jean D. , Seldin Donald W.
Published: December 2017

The rate and magnitude of ammonia excretion and renal glutaminase adaptation is normal in adrenalectomized rats given moderate (up to 4 mEq/day) amounts of NH4Cl. The administration of large amounts of NH4Cl (5 mEq/day or more) invariably kills adrenalectomized rats. Shortly before death, renal glutaminase adaptation was normal. Survival of adrenalectomized rats on large amounts of NH4Cl could be prolonged if potassium was eliminated from the diet. Notwithstanding the prevention of hyperkalemia by restricting potassium intake and salt depletion by the provision of adequate amounts of sodium chloride, ammonia excretion is impaired in rats given large doses of NH4Cl despite normal adaptation of renal glutaminase. It is suggested that adrenal steroids are not involved in either the maintenance or activation of the glutaminase enzyme system in the kidneys of rats. In adrenalectomized rats given large doses of NH4Cl, the diminished excretion of ammonia appears to be a consequence of a diminished Na+–H+ exchange resulting from two disturbances: a) reduced delivery of Na+ to distal tubular exchange site, owing to peripheral circulatory insufficiency arising from salt depletion or potassium intoxication; b) a specific impairment of tubular reabsorption of Na+ owing to the absence of adrenal steroids.
Alterations in Cardiovascular and Renal Hemodynamic Function Following Hypophysectomy in the Dog
Authors: Goodkind M. Jay , Davis James O. , Ball Wilmot C. , Bahn Robert C.
Published: December 2017

In studies of unanesthetized dogs, hypophysectomy resulted in a decrease in cardiac output, oxygen consumption, and stroke volume. No appreciable change in arteriovenous oxygen difference, mean femoral arterial pressure, or heart rate was observed. Glomerular filtration rate, renal plasma flow and renal fraction of cardiac output were markedly reduced in the hypophysectomized animals. Renal vascular resistance increased two- to threefold in contrast to a 24% increase in total peripheral vascular resistance. Although a marked reduction in cardiovascular and renal hemodynamic function resulted following hypophysectomy, there was no correlation between the degree of functional change and either the amount of anterior pituitary tissue remaining or the degree of atrophy of the adrenal cortex.
Analysis of the Chemical Sucrose Determination of Extracellular Fluid Volume Using C14-Labeled Sucrose
Authors: Harrison Charles S. , Faler Kenneth T.
Published: December 2017

An isotope method is presented which allows the disappearance rate of sucrose to be followed for 4 hours. The disappearance slope was found to be an ever changing one over this period of time. Extracellular fluid volume determinations based upon extrapolation of the disappearance rates of sucrose are questioned.
Effect of Sympathetic Blocking Agents on the Toxic Action of O2 at High Pressure
Authors: Johnson Paul C. , Bean John W.
Published: December 2017

The effects of sympathetic blocking agents were studied on rats exposed to O2 at 80 lb. gauge pressure. The ganglionic blocking agents TEAC and hexamethonium reduced the usual convulsive response, lung damage and mortality to a significant degree. On the other hand, the peripheral sympatholytic agents dibenamine, Dibenzyline, and SKF 501 (N-(9-fluorenyl)-N-ethyl-ß-chlorethylamine) lacked a notable effect on the somatic seizure but definitely reduced the pulmonary pathology and mortality. The drug SKF 501 was also found to protect animals exposed to O2 at 80 lb. 80 mm Hg pCO2. But this protection was seen only in the lungs, mortality was about the same as the normals simultaneously exposed. These experiments suggest that hyperactivity of the sympathetic nervous system is the factor primarily responsible for the pulmonary edema and congestion resultant from OHP. It is further indicated that this system also contributes significantly to the hyperoxic seizure and the incidence of mortality.
Effect of Chronic Hemorrhage on Urinary Aldosterone-Like Activity and Sodium Excretion in Dogs
Authors: Goodkind M. Jay , Ball Wilmot C. , Davis James O.
Published: December 2017

Chronic hemorrhage in normal dogs resulted in increased urinary aldosterone-like activity and a reduction in renal sodium excretion which was approximately equivalent to the sodium content of the blood removed. Glomerular filtration rate either increased or did not change. A comparable increase in aldosterone-like activity was observed in urine from normal dogs fed a low sodium diet equivalent to the net sodium intake of dogs subjected to hemorrhage.
Circulatory Reaction of Tolerant and Nontolerant Dogs to Polyvinylpyrrolidone and of Rats to Dextran
Authors: Marshall L. H. , Hanna C. H.
Published: December 2017

In dogs the decrease in mean arterial blood pressure and appearance of gross signs after rapid intravenous injection of 350 mg PVP/kg became less severe after pretreatment with the colloid. When the same dosage was injected 1 hour previously, the reaction was completely absent in 9 dogs out of 12, and the remainder were relatively refractory. Refractoriness in rats to a second injection of dextran (600 mg/kg) was demonstrated in the same manner. The blood pressure pattern, erythema and edema with extravasation of dye indicate that both colloids produce in the sensitive species an initial vasodepressor action followed by capillary permeability changes. No vasodepressor reaction occurred in relatively tolerant dogs given dialyzed PVP.
Anemia in Relation to Survival Following Thermal Injury in the Rat
Authors: McCarthy M. D. , Amrein M. B. , Cobb M. , Neerhout R. , Blackburn V.
Published: December 2017

Hematocrits, erythrocyte and reticulocyte counts were determined in rats receiving burns of 20%, 32% and 50% of the body surface and in three unburned control groups. All burned rats showed an immediate precipitous depression of hematocrits and erythrocyte counts. These were considerably lower at 24 hours postburn than the values in the control group which was bled. Erythrocyte depression during the 1st week postburn was directly related to extent of injury in the animals surviving for 24 weeks. No such correlation existed for those rats that died. No correlation was found between the immediate degree of anemia and death or survival. A secondary erythrocyte depression occurred in those animals that survived 24 weeks following burns of 32% and 50% of the body surface but did not develop in the 20% body surface burned animals surviving for 24 weeks. The erythrocyte counts in all control groups were above base line values at the end of the 24-week observation period. Elevated reticulocyte counts which were inversely related to the erythrocyte counts occurred in all burned animals surviving 24 weeks. The reticulocyte counts in all unburned groups were below base line at the end of the 24-week observation period.
Electrolyte Transfer During Hypothermia and Anoxia in Dogs
Authors: Gollan Frank , Rudolph Guilford G. , Olsen Norman S.
Published: December 2017

Electrolyte changes were studied during artificial respiration and hypothermia in dogs which had been equilibrated with K42, Na24 or B82. In the hypothermic animals potassium in plasma, potassium and sodium in skeletal muscle and potassium in auricle decreased, whereas bromide in the auricle increased. In normothermic animals anoxia produced an increase of bromide in the skeletal muscle and of sodium in the auricle; potassium increased in the plasma and decreased in the myocardium. Anoxia during hypothermia resulted in a loss of potassium from the contracting heart as the only significant change. Potassium to sodium ratios decreased more in the auricle than in the skeletal muscle in both hypothermia and anoxia. Thus, increased myocardial irritability during hypothermia and anoxia is caused or accompanied by a loss of potassium and an inability to extrude sodium.
Role of Hemoglobin Affinity and Concentration in Determining Hypoxia Tolerance of Mammals During Infancy, Hypoxia, Hyperoxia and Irradiation
Authors: Barker J. N.
Published: December 2017

The affinity of hemoglobin for oxygen is a major factor in determining the hypoxia tolerance of various species, and the increased hypoxia tolerance characteristic of infants and altitude-exposed animals. Modifications of affinity of hemoglobin, and probably hemoglobin type, occur in both young and adult animals of some species when exposed to alterations of O2 tension or irradiation. These modifications are not dependent upon splenic activity nor changes in oxygen capacity, but may be induced by intraperitoneal injection of serum from altitude-acclimatized rats. Maximal increases in tolerance are achieved only under optimal conditions of O2 tension, duration and frequency of exposure to hypoxia. No significant effect upon hypoxia tolerance due to alterations of O2 capacity could be demonstrated during growth, acclimatizations or blood loss and transfusion.
Micropuncture Study of Pressures in Proximal and Distal Tubules and Peritubular Capillaries of the Rat Kidney During Osmotic Diuresis
Authors: Gottschalk Carl W. , Mylle Margaret
Published: December 2017

A method is described for the identification of proximal and distal tubules on the surface of the living rat kidney. In 32 anesthetized rats, under control conditions, the hydrostatic pressure in the proximal tubules averaged 12.5 ± 2.2 mm Hg and 6.7 ± 1.6 mm Hg in the distal tubules. During infusion of hypertonic solutions of mannitol, glucose, urea and sodium chloride, the lumina of the proximal and distal tubules dilated and the intratubular pressures and rate of urine flow increased. Also during diuresis, the clear-cut difference between proximal and distal intratubular pressures disappeared and, in general, there was a linear relation between distal intratubular pressure and rate of urine flow. These results are interpreted to mean that the collecting system is a limiting factor in the outflow of urine from the kidney, and is an important determinant of the intratubular pressure, particularly at high rates of urine flow.
Relation of Secretin to the Parasympathetic Mechanism for Pancreatic Secretion
Authors: Lin T. M. , Ivy A. C.
Published: December 2017

By injecting 20 U of secretin intravenously into the anesthetized pancreatic fistula dog every 20 minutes for 2–5 hours, a basal condition is reached in which reproducible amylase and volume outputs are obtained in response to secretin and certain drugs. During the response to large doses of secretin given as a single dose or by continuous intravenous infusion, the administration of pancreozymin, methacholine, Urecholine (bethanacol) or acetylcholine caused an increase in amylase concentration with no increase in volume output. The parasympathomimetic agents produced a slight increase in volume output only when given with small doses of secretin. With large doses of secretin, peripheral stimulation of the vagus above the diaphragm caused either a decrease or no change in the total volume output; amylase concentration was always increased with an adequate stimulus. The same holds for acetylcholine. The record of drops of pancreatic secretion does not always accurately reflect the actual change in volume output. In the pentobarbitalized dog weighing 10 kg 1 µg of methacholine or Urecholine consistently increased the concentration of amylase. Urecholine given alone had only an ecbolic effect.
Role of Serotonin in Blood Coagulation
Authors: Milne W. L. , Cohn S. H.
Published: December 2017

Effects of serotonin (5HTA) were studied a) in whole blood ( in vitro) from both normal and x-irradiated animal, and b) in isolated clotting systems of plasma and purified fibrinogen. 5HTA was found to play an active role in blood coagulation in addition to its previously demonstrated role as a vasoconstrictor. In whole blood from normal and irradiated animals, and in platelet-deficient plasma, 5HTA acts in a manner similar to platelet factor 2 in accelerating the conversion of fibrinogen to fibrin. In a purified fibrinogen solution, 5HTA inhibits the fibrinogen-fibrin reaction, and thus differs from platelet factor 2. This may be due to the absence of an antithrombin in the purified fibrinogen solution. Serotonin appears to have a therapeutic effect on the postirradiation coagulation defect in that it decreases the prolonged heparin clotting time. This increased sensitivity to heparin during the postirradiation thrombocytopenia may be due to a deficiency of serotonin, which acts as an antagonist to heparin (an antithrombin). The action of 5HTA is postulated as an antagonist of an antithrombin which blocks the fibrinogen to fibrin reaction.
Effects of l-Epinephrine and l-Norepinephrine on the Splanchnic Bed of Intact Dogs
Authors: Farrand E. Allbaugh , Larsen R. , Horvath Steven M.
Published: December 2017

The changes in splanchnic blood flow and related metabolic functions which occurred as the result of the infusion of 0.1 µg/kg/min. of l-epinephrine and l-norepinephrine for 10 minutes were measured in anesthetized dogs. l-Epinephrine elicited a marked increase in estimated splanchnic blood flow and no change in mean arterial pressure. While a significantly increased mean arterial blood pressure was observed following the administration of l-norepinephrine, no change in estimated splanchnic blood flow occurred. Arterial oxygen content was increased significantly with both drugs. Utilization of oxygen by the splanchnic bed was not changed during the infusion of either drug but was increased during the postepinephrine infusion period.
Liver Function Changes in Hemorrhagic Hypotension
Authors: Manfredi Roland A. , Ingraham Raymond C.
Published: December 2017

Hemorrhagic hypotension was induced in a series of 10 animals by reducing the mean arterial blood pressure to 40 mm Hg for 90 minutes producing a mean bleeding volume of 57.5 cc/kg. The urinary excretion of galactose, the Rose Bengal clearance and the serum alkaline phosphatase show a definite alteration of liver function in these animals. In the animals that survived, this depression of liver function was reversible and returned to normal by the 10th day.
Isolation of Platelet Cofactor I From Plasma and Some Properties of the Preparation
Authors: Seegers Walter H. , Landaburu Ricardo H. , Fenichel Richard L.
Published: December 2017

A method for the purification of platelet cofactor I is described. Platelet cofactor II is first removed from plasma by adsorption on barium salts. The plasma is brought exactly to ph 6.3 for adsorbing the platelet cofactor I on kaolin, from which it is eluted at ph 7.5 with phosphate buffer. The activity is concentrated by precipitation with cold alcohol and further purified by salt fractionation. The isoelectric point of platelet cofactor I is ph 6.3–6.4. The activity is quite stable within the ph range 6–7.5 and can be preserved for many months in 50% glycerol solutions kept in a deep freeze. The protein contains less than 0.2% tyrosine, about 3.6% carbohydrate, and hexosamine. The activity is easily destroyed by heating near 30°C and above heat inactivation of solutions occurs.
Effect of Fasting on Protein Release by Liver Slices
Authors: Kaufmann Elisheva , Wertheimer E.
Published: December 2017

The release of total nitrogen from rat tissue slices into an artificial medium was investigated under different experimental conditions. Protein was found to be the main nitrogeneous component released. Liver slices from fed rats release much less total nitrogen into the medium than those from fasted rats. This fasting effect is specific for liver tissue. A protein-free diet lowers total nitrogen release from liver slices, whereas a protein-rich diet raises it. Refeeding either the stock diet or a protein-free diet for one night after a 5-day fast, lowers total nitrogen release to the level of that in fed animals. However, this is not the case after refeeding a low-ration diet. The fasting effect does not exist in rats fed a fat-rich, carbohydrate-free diet; it is lower than usual in rats fed a protein-rich, carbohydrate-free diet. The administration of glucose by stomach tube to fasted rats lowers total nitrogen release to normal fed levels in 2 hours.
Lipogenesis From Carbohydrate in the Negative Caloric Balance State Induced by Exposure to Cold
Authors: Masoro E. J. , Asuncion Carmen L. , Brown Richard K. , Rapport David
Published: December 2017

The ability of rats exposed to 0–2°C for 1 or 2 days to incorporate dietary glucose isotopic carbon into fatty acids was studied. Under these circumstances, in spite of a large intake of food, there is a loss in body weight and fatty acids. Whether calculated on a percentage or an absolute basis, there is under the conditions a considerable incorporation of the label into fatty acids. It is concluded that not only in the steady state, but also in a state of negative caloric balance, lipogenesis is one of the obligatory pathways of carbohydrate metabolism.
Changes in Blood, Plasma and Red Cell Volume in the Male Rat, as a Function of Age
Authors: Garcia Joseph F.
Published: December 2017

Using the Fe59-labeled cell dilution technique, the blood, plasma and red cell volume and total circulating hemoglobin have been determined on 259 male rats varying in age from 1 to 340 days. An anemic period exists in the male rat which is maximal between 15 and 20 days of age. This anemia is observed in terms of a decrease in the volume of red blood cells per gram of rat as well as in hematocrit and hemoglobin concentration values. However, throughout this anemic period there is a continual increase in total red cell volume and, in fact, the daily gain of red blood cells per gram of rat is greater during this period than at any time thereafter. In spite of the very high rate of erythropoiesis occurring at this time the growth of the body mass as a whole exceeds it and so for a time anemia results.
Radioiron Time-Distribution Studies at Various Ages in the Normal Male Rat
Authors: Garcia Joseph F.
Published: December 2017

The distribution of radioiron with time has been studied in the plasma, red cells, liver, spleen, marrow, muscle and kidney in rats 15, 50, 150 and 250 days of age. The plasma clearance of Fe59 is very rapid in the two youngest ages studied and much slower in the 150- and 250-day-old rats. Fe59 enters the red cell most rapidly in the 15- and most slowly in the 250-day-old rats. Plasma and red cell iron turnovers were calculated. Approximately equal values for total red cell iron turnover were obtained for rats of 50, 150 and 250 days of age regardless of wide differences in body weight. The red cell iron turnover, relative to body weight was highest in the 15-day-old rats, being approximately three times that calculated for the 150- and 250-day-old rats.
Hypothermic Myocardial Oxygenation
Authors: Jude James R. , Haroutunian L. M. , Folse Roland
Published: December 2017

Coronary blood flow together with corollary functions were determined in 11 anesthetized dogs at normal body temperature and in 9 of these animals after cooling to 20°C. The arterial ph was kept in the normal range by controlled ventilation. At 20°C coronary blood flow/100 gm left ventricle decreased to 29% of the normothermic control value. Myocardial oxygen consumption decreased to 24%, coronary A-V oxygen difference to 82%, total body oxygen consumption to 24%, cardiac output to 21%, and calculated left ventricular work to 10.7%. Systemic A-V oxygen difference did not vary significantly. Pulmonary vascular resistance increased to 306% of the normothermic control, peripheral resistance to 304% and coronary vascular resistance to 193%. Coronary blood flow appeared to be sufficient to maintain an adequate supply of oxygen to the myocardium for the work performed by it at 20°C.
Actions of Diethylstilbestrol in the Albino Rat
Authors: Hartsook E. W. , Magruder N. D.
Published: December 2017

Four experiments were conducted utilizing either weanling or young adult normal male albino rats. These animals were fed either stock diets or semi-synthetic diets, containing either 0, 0.15, 0.3, 0.6 or 2.4 µg of diethylstilbestrol/gm, either by the trio or ad libitum feeding technique for periods of 6–15 weeks. It is concluded that diethylstilbestrol feeding in the albino rat induces statistically significant decreases in body weight gain, feed efficiency, body length, and testes size; it induces statistically significant increases in basal metabolic rate and in pituitary, thyroid and adrenal sizes.
Protective Effect of a Sucrose Diet in Mercuric Chloride Poisoning
Authors: Surtshin A.
Published: December 2017

Rats fed only sucrose and vitamins for 3 weeks or more usually survive intravenous injection of 3 mg/ kg of mercuric chloride, a dose lethal for rats on a normal diet. Survivors returned to a normal diet grow rapidly and appear grossly normal. Survival occurs in the presence of a diminished rate of excretion of radiomercury and a renal concentration and content of radiomercury higher in sucrose-fed protected rats than in unprotected rats on a normal diet. Sucrose feeding itself causes slower excretion of mercury; evidence indicates that the renal binding of mercury in protected rats is greater than in the unprotected. Some sucrose-fed rats surviving an initial dose of mercuric chloride, survive additional doses after return to a normal diet. The excretion and renal content of mercury is not altered by ammonium chloride acidosis in chow-fed rats given mercuric chloride.
Significance of Innervation in the Function of the Gastric Antrum
Authors: Oberhelman Harry A. , Rigler Stanley P. , Dragstedt Lester R.
Published: December 2017

The antrum of the stomach in dogs was excluded by constructing a membrane of gastric mucosa separating the cavity of the antrum from that of the corpus. A fistula was made of the pylorus and intestinal continuity re-established by anastomosing the corpus of the stomach to the open end of the duodenum. A vagus denervated Heidenhain pouch was also prepared. With this type of preparation it was found that insulin hypoglycemia produced a marked stimulation of gastric secretion from the Heidenhain pouch. Furthermore, with the antrum excluded from contact with the gastric contents but with its innervation preserved, the secretory response of the Heidenhain pouch to the ingestion of food was not only not reduced but was actually prolonged. These effects can be accounted for by peristaltic activity in the antrum induced by the peristalsis of digestion in the main stomach and enhanced by the absence of the usual inhibitory effect of acid gastric content on the release of gastrin. Insulin hypoglycemia produced vigorous contractions in the isolated antrum with intact vagus innervation.
Relative Potencies of Thyroxine and Triiodothyronine Based on Various Criteria in Thiouracil-Treated Chickens
Authors: Newcomer W. S.
Published: December 2017

Relative sensitivities of various criteria, which were found to be suitable qualitative indicators of thyroxine and triiodothyronine, were determined by calculating and comparing the amounts of each hormone necessary to maintain the control level of each criterion in thiouracil-treated chicks. Relative sensitivities of the criteria used for determining action of thyroxine were: feather length > rectal temperature > weight of the thyroid > oxygen consumption rate > heart rate > suffocation time; of triiodothyronine: feather length > rectal temperature > suffocation time > thyroid weight > oxygen consumption rate > heart rate. Relative potencies of thyroxine and triiodothyronine were determined by comparing the magnitudes of responses of each of the above criteria to equal or equivalent quantities of these two hormones. Thyroxine and triiodothyronine exhibited equal potency in affecting the above criteria in thiouracil-treated chicks except for a) antigoiterogenic action in which case thyroxine was more potent than triiodothyronine and possibly b) elevation of rectal temperature for which action triiodothyronine appeared to be the more potent hormone.
Ineffectiveness of Carnitine as a Choline Substitute in the Prevention of Fatty Livers of Rats Maintained on a Choline-Deficient Diet
Authors: Fritz Irving B. , DuPont Phil
Published: December 2017

Carnitine supplementation of choline-deficient diets did not prevent fatty liver formation of rats maintained on this regimen.
Phosphate Exchange in Marrow-Filled and Pneumatized Bones of Birds
Authors: Smith Arthur H. , Reck D. Glenn , Luick Jack R.
Published: December 2017

Uptake of radiophosphate in the 24 hours after its intravenous injection is much greater in the avian femur (marrow-filled) than in the avian humerus (‘pneumatized’). In animals in which both bones contain marrow, the work of others indicates no difference in the phosphate exchange of these bones. It is concluded that the presence of bone marrow (and perhaps only its vascularity) has a great influence on the phosphate exchange of bone.
Cardiovascular Changes of the Burned Dog Following the Infusion of Intravenous Solutions
Authors: Gilmore J. P.
Published: December 2017

Cardiovascular responses of the burned dog to infusions of dextrose-saline, dextran, plasma and gelatin have been studied using changes in cardiac output as well as in plasma volume as a measure of therapeutic effectiveness. The experimental results demonstrate that restoration of plasma volume does not necessarily indicate good restoration of cardiac output, nor does restoration of cardiac output necessarily indicate restoration of plasma volume. Of the infusions studied, plasma and dextran appear to be equally effective, dextrose-saline least effective and gelatin intermediate.
Oxidation of Carbon14-Labeled Glucose, Pyruvate and Succinate by Isolated Contracting Myocardium
Authors: Hood James E. , Saunders Paul R.
Published: December 2017

Oxidation of C14-labeled glucose, pyruvate and succinate at ph 6.2 and 7.4 by isolated contracting and resting rat ventricular strips which had become hypodynamic after prolonged contraction in substrate-free medium was studied; in addition, the effects of these substrates upon the force of contraction of the strips were investigated. The inability of succinate at ph 7.4 and of glucose at ph 6.2 to maintain contractile activity was found to be associated with failure of these substances to be oxidized at appreciably greater rates by contracting than by resting muscle. However, substantial recovery together with greater utilization by contracting than resting strips occurred with succinate at ph 6.2 and glucose at ph 7.4. On the other hand, the oxidation of pyruvate and its effect upon the force of contraction of the myocardium were not significantly different at these two ph values; in both cases substantial recovery of activity together with an increased rate of oxidation by contracting strips occurred.
Phosphate Transfer in Chicken Erythrocytes
Authors: Gourley D. R. H.
Published: December 2017

Chicken erythrocytes centrifuged at 1300 g for 1 hour trap plasma to the extent of 7.8% of their apparent volume. The rate of P32 transfer is not directly proportional to the cell volume in chicken blood but an empirical formula is given for correcting observed rates to a standard hematocrit of 30%. P32 transfer is slower in chicken blood than in human blood although glucose utilization is higher in chicken blood. P32 transfer in chicken blood has the characteristics of a first-order process and a study of the rates at different temperatures suggested that the process is chemical in nature but different from the corresponding process in human blood. P32 transfer in chicken erythrocytes is inhibited, but not completely, by monoiodoacetate, sodium fluoride, sodium azide, sodium orthoarsenate, or lack of oxygen. Dinitrophenol has no effect. Complete inhibition was not observed when inhibitors were combined to block both aerobic and anaerobic metabolism. It is concluded that energy for phosphate transfer in chicken erythrocytes is provided by glycolysis as well as oxidative reactions and possibly other metabolic pathways.
Weight and Composition of Organs During the Reproductive Cycle in the Rat
Authors: Souders Helen J. , Morgan Agnes Fay
Published: December 2017

Observations of 11 organ and gland weights in 40 parturient, 38 lactating, 26 resting and 79 unmated female rats were statistically analyzed for significant changes. One day after parturition there was an increase in absolute and relative weights of the liver and uterus and absolute weight of the ovaries compared with those of unmated littermate controls. Adrenal and thymus weights were decreased relative to body weight. After 3 weeks of lactation the pregnancy changes in liver, adrenal and thymus weights persisted. In addition, there was an increase in the relative and absolute weights of the heart, kidneys, and empty washed intestine. All organ and gland weights except that of the heart returned to the control levels 21 days after weaning a litter of seven or eight. These increases in weight of liver, kidneys and intestine were not accompanied by appreciable changes in moisture, fat or total nitrogen except for a significant increase in fat and decrease in nitrogen in the heart following lactation.
Effect of Fasting and Realimentation With Diets High in Carbohydrate or Protein on Blood Pressure and Heart Rate of Sympathectomized Dogs
Authors: Wilhelmj C. M. , Carnazzo A. J. , McCarthy H. H.
Published: December 2017

Six dogs were studied following bilateral paravertebral ganglionectomy and denervation of the adrenal glands. After the operation systolic pressure and pulse rates were within the normal range while diastolic pressure tended to be at the lower limits of normal. During fasts of from 3 to 6 weeks duration blood pressure did not show the fall characteristic of normal dogs but remained the same, or more often, rose above the control level. The pulse rate decreased. When fasted normal dogs were fed a luxus consumption high carbohydrate diet, systolic pressure and pulse rate rose significantly above fasting and control values while diastolic pressure was normal or low. When fasted sympathectomized dogs were similarly realimented the blood pressure remained at the fasting level but the pulse rate rose. When luxus consumption diets of horse meat or casein were fed to sympathectomized dogs the blood pressure remained at or below the fasting value.