bluuebunny/crossref_metadata_2025 huggingface dataset:
Extensibility of Gastrocnemius Muscle at Rest and During Contraction
Authors: Thomson J. D.
Published: December 2017

The medial head of rat gastrocnemius shows greater static and semidynamic passive tension (per cm2 cross-section area) than the lateral head. Regarded as two resistances in parallel, resistance of lateral and medial heads together (1.16 and 4.71 mm/sec., 1–5 mm stretch) approximate resistance of whole muscle. Resting muscle shows a slow rise and low tension at 0.29 mm/sec., a rapid rise and higher tension at 1.16 mm/sec., and declining tension rise and level with faster stretches. The lateral head yields more readily than the medial head. The lateral head controls whole muscle's reaction to stretch at rest. Tetanized (15 cps) muscle shows a linear, faster tension rise with faster stretches. Excess (over isometric) tension, related to resting stretch tension, shows a decline with stretch (yielding). The amount of excess tension increases with speed of stretch. The lateral head shows less excess tension rise than the medial head. The medial head controls whole muscle's reaction to stretch during isometric tetanus.
Inhibition of Histamine Release in Experimental Diabetes
Authors: Goth Andres , Nash W. L. , Nagler Mary , Holman James
Published: December 2017

Alloxan diabetic rats failed to show the characteristic edema and elevated plasma histamine levels which follow the intravenous injection of dextran or egg white. Pretreatment with insulin restored the ability of these rats to respond in a normal fashion. Insulin in normal rats promotes edema formation and histamine release induced by dextran or egg white. In contrast to these findings, neither diabetes nor insulin pretreatment exerted an influence on the response of rats to intravenously injected compound 48/80. These results suggest a hitherto unrecognized role of insulin in certain types of inflammation and histamine release.
Failure of Chronic Adrenal Venous Congestion to Produce Sodium Retention and Increased Aldosterone Excretion in the Dog
Authors: Ball Wilmot C. , Davis James O.
Published: December 2017

Four dogs were studied before and after constriction of the inferior vena cava immediately above the entrance of the adrenolumbar veins. Despite a high venous pressure below the constricting ligature, the dogs failed to show increased aldosterone excretion, sustained sodium retention or ascites formation. These changes, which are observed regularly in dogs with constriction of the inferior vena cava in the thorax, are apparently related to hepatic venous congestion rather than elevated adrenal venous pressure.
Role of Essential Amino Acids in the Early Formation of Avian Liver Xanthine Dehydrogenase Activity
Authors: Litwack Gerald , Fisher Hans
Published: December 2017

Avian liver xanthine dehydrogenase (LXD) has been shown to be sensitive to dietary proteins and amino acids particularly when measured during the first 3 weeks of life. Feeding an adequate diet for the first 7 days of life produces a condition wherein LXD is very resistant to single essential amino acid deficiencies. When an amino acid-deficient regimen is fed directly, without prefeeding an adequate diet, a rapid and marked decrease is seen which is inversely proportional to the amount of available limiting amino acid. This mechanism has also been demonstrated by LXD depletion with low dietary protein and repletion with diets high in protein but limiting in a specific amino acid. In the case of l-threonine deficiency, a dietary level of threonine above that required to saturate a growth response produced a continuous rise in LXD specific activity similar to induction.
Ciliary Streaming in the Lower Respiratory Tract
Authors: Hilding A. C.
Published: December 2017

Ciliary streaming in the bronchial tree follows a definite system. Flow begins at the level of the respiratory bronchioles in a very wide stream-bed (meters in total width). The stream-bed narrows rapidly until, when the trachea is reached, it is only some 50 mm in width. A continuously increasing volume of mucus, furnished by the glands throughout the bronchial tree, is added to the stream as it flows toward the larynx. With the stream-bed becoming progressively and sharply narrower, this means that the depth of the mucous blanket or the velocity of flow must increase greatly. En route from the periphery toward the larynx, many obstructions are encountered in the form of tributary bronchial openings. At such obstructions, the mucous blanket passes to the margin of the opening and then divides into two parts that flow in almost opposite directions around the bronchial openings. The direction of ciliary beat changes where bronchial openings are encountered. Sometimes retardation of flow or actual stasis occurs in the center of the lip where division takes place. This may take the form of a whirlpool. Where several bronchi join very close together, the ciliary stream-bed may be reduced to a few millimeters. Islands of cells devoid of cilia occur in the tracheobronchial tree.
Hemodynamic Alterations Following Miliary Pulmonary Embolization in Relation to the Pathogenesis of the Consequent Diffuse Edema
Authors: Singer Donald , Saltzman Paul W. , Rivera-Estrada Carmen , Pick Ruth , Katz Louis N.
Published: December 2017

In an effort to further elucidate the pathogenesis of the severe, diffuse lung edema attendant upon unilobar miliary pulmonary embolization with starch, serial recordings of several hemodynamic variables were made during the course of the procedure. Of the animals studied, some were embolized without prior medication while the remainder were pretreated with a variety of drugs, some of which depressed edema formation to varying degrees. A small group of the control preparations were injected into the right ventricle, giving rise to a disseminated, rather than to a localized, starch distribution (without edema formation). Of the pressures measured, only the left atrial pressure remained essentially unchanged during the entire course of the procedure, both in the control and the premedicated groups. This serves to effectively exclude left ventricular failure as the cause of the edema formation in our experiments. Both pulmonary arterial wedge and pulmonary venous pressures exhibited a modest rise after embolization, the peak values of which did not exceed even the lower values for plasma oncotic pressure. Similar increments were recorded in both control and pretreated groups, regardless of whether edema had or had not formed. In the light of these findings, it is unlikely that the capillary hydrostatic pressure alterations reflected by the pressure changes could be held primarily responsible for the edema, although they may possibly play an ancillary role in its initiation and/or perpetuation. If the edema formation is independent of the capillary hydrostatic pressure changes produced by the starch, other mechanisms must be considered, particularly a primary alteration of the permeability of the pulmonary capillaries. In the light of our previous deduction on the basis of other data to the effect that a neurogenic or neuro-humoral mechanism may be involved, it is concluded that the neurogenic or neuro-humoral mechanism may act to regulate capillary permeability.
Effects of Unilateral Hypoxia and Hypercapnia on Pulmonary Blood Flow Distribution in the Dog
Authors: Borst Hans G. , Whittenberger James L. , Berglund Erik , McGregor Maurice
Published: December 2017

Effects of hypoxia and of hypercapnia on pulmonary blood flow distribution were examined in 19 dogs. The blood flow through each lung was continuously recorded; the test gas was administered to one lung, and the other lung was used as the control. Low oxygen gas mixtures were administered to one lung for periods of 2–47 minutes. When constriction occurred, it began within one-half minute after the gas administration was started and reached a plateau within 8–20 minutes. Vasodilation was never observed. In most animals no vasomotor effect of hypoxia was found early in the experiment (less than 6 hr. after induction of anesthesia), but seven of the early nonreactors became positive later in the experiment. After 6–8 hours from induction of anesthesia, all animals tested showed a vasoconstrictor response to hypoxia. The administration to one lung of 5 or 10% carbon dioxide for 2–10 minutes was always accompanied by vasoconstriction in that lung. In dogs that showed unilateral pulmonary vasoconstriction during hypoxia, further vasoconstriction was produced by adding 5% carbon dioxide. Some of the contradictory results of other investigators may be explained by the refractory period observed in these experiments.
Physiological Factors Influencing Pulmonary Artery Pressure During Separate Perfusion of the Systemic and Pulmonary Circulations in the Dog
Authors: Weil Peter , Salisbury Peter F. , State David
Published: December 2017

An open-chest dog preparation is described in which the systemic circulation is perfused by a heart-lung machine and the lesser circulation is perfused by a pump-reservoir circuit. In this preparation there is no connection between the two circulations other than the bronchial flow; the flow in the pulmonary vessels is known and controlled at all times. The influence of physiological variables on pulmonary artery pressure was investigated and the results of earlier investigations were confirmed with reference to pressure-flow relationships, the effect of changes in pulmonary ventilation (in part), the inhalation of CO2, pulmonary air embolism, the lack of effect of changes of systemic arterial pressure. Increases of systemic venous pressure caused simultaneous increases of pulmonary arterial pressure.
Effects of Increased Reflex Sympathetic Activity on Contractile Force of the Heart
Authors: Cotten Marion deV. , Moran Neil C.
Published: December 2017

Reflexly induced changes in cardiac contractile force and arterial pressure in vagotomized dogs were compared with those produced by direct postganglionic cardiac sympathetic nerve stimulation, by i.v. injections of l-norepinephrine and by elevation of the intracranial pressure. Bilateral carotid occlusion and central vagal and central sciatic nerve stimulation produced a marked rise in arterial pressure but only a moderate increase in right ventricular contractile force. In contrast, direct stimulation of the cardiac sympathetic nerves and selected doses of l-norepinephrine caused a marked increase in right ventricular contractile force with only moderate elevation of blood pressure. Further, reflex stimulation resulted in a moderate dilation of the left ventricle in contrast to a reduction in size produced by l-norepinephrine. Elevation of the intracranial pressure provoked marked increases in both blood pressure and right ventricular contractile force. Experiments with vagotomized cats gave comparable results. The moderate positive inotropic effect of carotid occlusion in dogs was mediated both through the cardiac sympathetic nerves and the adrenal glands since removal of either structure alone reduced the response while combined adrenalectomy and cardiac sympathectomy abolished the effect. These results indicate that the predominant effect of reflexly augmented sympathetic activity through the carotid sinus, vagus and sciatic nerves is on vasomotor tone with only moderate influence on cardiac contractile force.
Sodium Exchange in the Frog Heart Ventricle
Authors: Johnson John A.
Published: December 2017

The isolated frog heart ventricle was used to study the kinetics of uptake and release of radioactive sodium. Sucrose was used as an extracellular space indicator. A flux of sodium across the ventricle cell membranes of 15 x 10–12 m/cm2 sec. was calculated from the data.
Sympathetic Control of the Circulation in the Hind Leg of the Dog
Authors: Petkovic Dragoljub S. , Husni Elias A. , Simeone F. A.
Published: December 2017

Experiments were undertaken to test the effects of ablation or stimulation of the lumbar sympathetic nerves upon the circulation of the skin and skeletal muscle in the hind leg of the dog. Insulation of the skin was abolished by wetting the fur. Insulation of the muscles was abolished by incising and reflecting the skin which covered the part to be studied. As indices of circulation, the temperatures of skin and muscle were recorded by means of thermocouples, and the tensions of oxygen in skin and muscle were recorded as measured by the polarograph. Most of the experiments were conducted in a room in which temperature and humidity were controlled. After chronic sympathetic denervation, the temperature and oxygen tension of skeletal muscle were lower than in the contralateral control. Those of the skin were higher than in the control side. Electric stimulation of the lumbar sympathetic trunk consistently caused a rise in the tension of oxygen in muscle and a fall in skin. This was not attributable to hematometakinesia but to active vasodilation in muscle. Changes in temperature were always in the same direction as changes in oxygen tension.
Nitrogen and Electrolyte Excretion of Rats Chronically Exposed to Adverse Environments
Authors: Mefferd Roy B. , Hale Henry B. , Martens Herman H.
Published: December 2017

Urinary excretion patterns of adult male Wistar rats exposed for 11 weeks to control (25°C) or to adverse conditions (5°C, 35°C), or simulated altitude (equivalent to 18,000 ft.) were determined using 24-hour fasting urine specimens collected weekly during the final 4 weeks. Relative to metabolic body weight (kg3/4), fasting water intake tended to vary directly with temperature, but urinary sodium, potassium, magnesium, calcium, phosphate, urea, valine and alanine tended to vary inversely with temperature. Creatinine, uric acid, histidine, glycine, serine, methionine, glutamic acid and aspartic acid excretion tended to vary nonlinearly with temperature. Altitude induced reductions in the majority of the urinary constituents.
Cephalic Phase of Gastric Secretion in the Rat
Authors: Lin T. M. , Alphin R. S.
Published: December 2017

Nineteen sham-feeding tests were performed on eleven rats with a chronic gastric and esophageal fistula. As compared with man and the dog, a slight increase in acid output occurred in 17 tests, the increase being quite definite in 13 tests. Sham feeding had no effect on gastric secretion in 16 tests on rats when performed from 1 to 14 days after bilateral vagotomy. The vagotomy had a profound depressing effect on the interdigestive secretion, no free acid being found in the fasting secretion in any of the rats during the period of these tests. The vagi exert a marked secretory tone on the gastric glands, but the conditioned secretion of gastric juice is probably not of much physiological significance in the rats studied in these tests.
Carbohydrate Metabolism in Rats With Acute Uremia
Authors: Boucot Nancy G. , Guild Warren R. , Merrill John P.
Published: December 2017

To define areas of carbohydrate metabolism which might be altered in uremia, determinations of gastric and intestinal absorption of glucose and deposition of glycogen in the liver of 9 acutely uremic and 24 control rats were performed. Residual gastric and intestinal glucose contents and hepatic glycogen contents were determined 3 hours after glucose lavage in rats fasted for 24 hours. No statistically significant difference was observed in gastrointestinal absorption of glucose and in hepatic deposition of glycogen of the uremic and control animals.
Mouse Proteinuria
Authors: Finlayson J. S. , Baumann C. A.
Published: December 2017

Normal adult male mice of various strains excreted 0.6–3.1 mg of urinary protein N/day; females, considerably less. Electrophoretic measurements showed the protein to consist of three components, all having negative mobilities (–7.5 to –8.3 cm2/volt/sec x 10–5 at ph 8.5) greater than that of mouse serum albumin (–6.3 ± 0.1 cm2/ volt/sec. x 10–5 at ph 8.5). The most negative, amounting to approximately 32% of the total urinary protein, had an isoelectric ph of 4.3; the least negative, 4.5. During ultracentrifugation the urinary protein sedimented as a monodisperse system with a sedimentation coefficient of 2.28 S and a weight—average molecular weight of 17,800. Electrophoresis of mouse serum revealed a small fast-moving component which may be identical with the urinary protein.
Effect of Intramuscular Administration of Antibiotics on the Oxygen Consumption of Normal and Hyperthyroid Rats
Authors: Vogel G. R. , Hauge S. M. , Andrews F. N.
Published: December 2017

The oxygen consumption of normal and hyperthyroid albino rats was measured before and after the intramuscular injection of 1.2 mg (0.2 ml of solution) of procaine penicillin G, Aureomycin or Ilotycin. The final measurements were observed at either 1- or 3-hour intervals after the injection. The antibiotics caused a statistically significant decrease in the rate of oxygen consumption in both normal and hyperthyroid rats. This effect diminished with time. Similar effects were observed with procaine penicillin G after oral administration by stomach tube. It is suggested that antibiotics may somehow influence the endocrine system, possibly the level of circulating thyroxin. Such studies are in progress.
Mechanism of the ‘Anti-Insulin’ Action of 11,17-Oxycorticosteroids in Hypophysectomized Dogs
Authors: Altszuler N. , Steele R. , Wall J. S. , de Bodo R. C.
Published: December 2017

In studies employing the intravenous administration of minute amounts of C14 glucose to tag the body glucose pool, the uptake of glucose by the tissues and the output of glucose by the liver were measured in unanesthetized dogs in the postabsorptive state prior to and subsequent to a small intravenous dose of glucagon-free insulin. In this way hypophysectomized dogs treated with hydrocortisone acetate (1.2–1.5 mg/kg/day for 9–18 days) were compared with untreated hypophysectomized dogs, and three important differences were observed. The steroid regimen a) restored to normal the low glucose turnover rate and the low plasma glucose concentration seen in the untreated hypophysectomized dog prior to the administration of insulin, b) reduced the increased responsiveness of the tissues to insulin stimulation of glucose uptake which is characteristic of the untreated hypophysectomized dogs, and c) restored to near the level seen in the normal dog the decreased capacity of the hypophysectomized dog to respond to hypoglycemia with an increase in glucose output by the liver. The decreased insulin sensitivity brought about in the hypophysectomized dog by an 11, 17-oxycorticosteroid regimen is due partly to a reduced capacity of the insulin dose to lower the blood sugar concentration and partly to an increased capacity of the treated animal to restore its blood sugar concentration to the normal level. The decreased capacity of administered insulin to stimulate extra glucose uptake by the tissues is considered to be secondary to the increased glucose turnover and to a postulated increased endogenous insulin secretion existing in the steroid-treated animal prior to insulin injection. Thus all three of the observed effects of the steroid regimen may be ascribed to a single change, namely the increased capacity of the liver to put glucose into the blood.
Resistance to Experimental Infection and Mobilization of Granulocytes in Irradiated Mice Treated With Bacterial Endotoxin
Authors: Smith Willie W. , Alderman Ilo M. , Gillespie Ruth E.
Published: December 2017

The ability of mice to respond to an intraperitoneal injection of Salmonella typhosa endotoxin with increased resistance to experimental Pseudomonas infection was studied over a period of 3 weeks following just sublethal irradiation, with and without lead shielding of the hind legs. In general, the increase in resistance paralleled the ability to mobilize granulocytes. No increase in resistance was observed 3 days after irradiation in the unshielded mice, while in the shielded mice the increase was only slightly less than in nonirradiated mice. In nonirradiated mice given a series of endotoxin injections, increased resistance to the infection persisted in the absence of a granulocytic response. This effect could be abolished by an intervening exposure to sublethal radiation. An intraperitonial injection of zymosan also increased resistance to the infection without producing a granulocytosis. The rapidly developing resistance to infection following an endotoxin injection was transitory and apparently is not responsible for the recently reported increase in survival of lethally irradiated mice.
Renal, Cardiovascular and Respiratory Responses and Their Interrelations During Hypothermia
Authors: Blatteis Clark M. , Horvath Steven M.
Published: December 2017

The renal circulation and its relationship to cardiovascular and respiratory functions during progressive reduction of rectal temperature and during a period of low, stable temperature was studied in eight dogs. Hypothermia was induced by total immersion of the animals in an ice-bath. The results demonstrated an exponential reduction of the gomerular filtration rate, renal blood flow, urine volume, minimal tubular excretory capacity of PAH and heart rate with the fall in rectal temperature. Respiratory rate and oxygen consumption also fell exponentially with temperature, but tended to return towards control levels during the stable phase of reduced body temperature. The filtration fraction was increased upon cooling, but declined abruptly during the period of stabilized rectal temperature. The tubular reabsorption of water and the hematocrit remained unaltered during the experiments. Blood pressure changes were variable, although the over-all trend indicated a decrease upon cooling and a recovery during the stable period. This study suggested a direct, depressant effect of cold upon the kidney, accompanied by concomitant cardiovascular and metabolic changes. These effects, however, did not appear to be functionally correlated in every case; rather, they were the simultaneous result of the influence of cold on all body tissues in accordance with van't Hoff's law.
Renal Citric Acid Utilization in the Dog
Authors: Herndon Richard F. , Freeman Smith
Published: December 2017

The renal uptake, metabolism and excretion of endogenous and exogenous citrate have been determined in unilaterally nephrectomized London cannula preparations with and without the presence of the thyroparathyroid apparatus. The uptake of citrate by the kidney is related to total renal plasma flow and consistently exceeds the extraction of creatinine. Only a small fraction of endogenous citrate removed from the blood passing though the kidney is excreted in the urine. The capacity of the kidney to metabolize circulating citrates is several times the endogenous renal uptake. Thyroparathyroidectomy reduced the endogenous renal uptake of citrate, but not the uptake when the plasma concentration was elevated by citrate infusion.
Effects of Feeding Diets Containing Sucrose, Cellobiose or Glucose on the Dry Weights of Cleaned Gastrointestinal Organs in the Rat
Authors: Moinuddin Jessie Fischer , Lee Helen Wing-Tsit
Published: December 2017

Compared to feeding basal (67%) cornstarch or 25% glucose or 25% sucrose diets, feeding a 15% cellobiose diet to rats for 4–5 weeks resulted in diarrhea, smaller body weight gains, greater small gut weight relative to body weight, greater absolute and relative weights of the cecum and of the colon plus rectum, and several differences in stomach weight. In a separate 4–4 1/2-week feeding experiment, the absolute and relative weights of the stomach in three dietary groups were in the order: 67% glucose > 67% sucrose > 67% cornstarch. Also 67% sucrose exceeded 67% cornstarch in absolute and relative small gut weights and in small gut weight: length ratio.
Changes in Intestinal Absorption and Plasma Concentration of Various Lipids After Ileal Reimplantation of Bile Duct
Authors: Byers Sanford O. , Friedman Meyer
Published: December 2017

Reimplantation of the common bile duct into the ileum of the rat at a distance of 80–100 cm distal to its initial duodenal site did not significantly alter the intestinal absorption of cholesterol or total lipid. Such reimplantation at 100 cm however did interfere markedly with absorption of cholate. Rats subjected to chronic reimplantation of the bile duct into the ileum at a distance of 80–120 cm from the initial duodenal site exhibited a decreased plasma concentration of both cholesterol and total lipid despite the ingestion of a cholesterol-enriched diet. It is suggested that excess intestinal loss of bile acids may lead to a significant fall in plasma lipids.
Vitamin D and Citrate Metabolism
Authors: Harrison Helen C. , Harrison Harold E. , Park Edwards A.
Published: December 2017

Three-week-old rats fed a vitamin D-deficient diet adequate in calcium and phosphorus show biochemical evidences of vitamin D deficiency without the characteristic bone changes of rickets. The significant findings are hypocalcemia and reduction of the concentrations of citrate in serum and bone with normal serum phosphorus levels. Body weight gain and bone weight increments are reduced in the vitamin D-deficient rat. One hundred units of vitamin D increases the serum calcium and citrate levels and the concencentration of bone citrate. Vitamin D-deficient rats show no response to parathyroid extract unless primed with vitamin D before injection of parathyroid extract. Feeding of cortisol to the vitamin D-deficient rat reduces serum and bone citrate concentrations and blocks the enhancing effect of vitamin D upon citrate levels. There is no necessary correlation between the concentration of citrate and of calcium in serum and suppression by cortisol of the vitamin D effect upon citrate concentrations does not inhibit the vitamin D effect upon calcium levels in serum.
Effect of Various Substances On Survival Times of Mice Exposed to Different High Oxygen Tensions
Authors: Gerschman Rebeca , Gilbert Daniel L. , Caccamise Daniel
Published: December 2017

Mice were exposed to various pressures of oxygen up to 10 atm. Survival times decreased abruptly between 0.7 and 1 atm. of oxygen, and reached a minimum value of 19 minutes at 10 atm. Cysteamine, reduced glutathione and thiourea had a detrimental effect at 1 or 1.5 atm. but protected mice at 6 atm. of oxygen. Cystamine and oxidized glutathione did not protect at 1 atm. but gave protection at 6 atm. of oxygen. AET (ß-aminoethylisothiuronium) gave no protection at 1 or 10 atm. but increased the survival time of mice exposed to 2 and 2.5 atm. Cobalt increased the survival time of mice exposed to 1 atm. and either exerted no influence or had a slight detrimental effect at higher oxygen pressures. Ca EDTA (calcium salt of ethylenediamintetraacetic acid) did not change the survival time of mice exposed to 6 atm. of oxygen. DEDTC (diethyldithiocarbamic acid sodium salt) increased the survival time of mice in 6 atm. of oxygen. Trihydroxyphenone antioxidants showed some protective effect against oxygen toxicity in mice exposed to 6 atm. of oxygen. The results are not inconsistent with the notion of a possible common mechanism between oxygen poisoning and x-irradiation. The action of any given agent was found to depend upon the oxygen pressure used.
Post-Mortem Diagnosis of Hypoxia by Means of Brain Lactic Acid Concentration
Authors: Van Fossan Donald D. , Clark Robert T.
Published: December 2017

Simulated altitude exposure elevates the postmortem brain lactic acid concentration up to 98 mg/100 gm above controls depending on species used, duration, and intensity of exposure. The sharp difference in post-mortem brain lactic acid concentration between altitude exposed animals and controls remains demonstrable for the longest postmortem intervals studied (20 hr. in the dog, 30 hr. in the rabbit, and 6 hr. in the rat). Upon recovery from altitude exposure the brain lactic acid and/or precursors return toward pre-exposure levels in accordance with first order reaction kinetics during the first few minutes. The velocity constant is .32 and the half-life is 2.2 minutes. Elevated post-mortem brain lactic acid concentration is a constant finding in animals which were hypoxic at the time of death and appears to be a suitable criterion for establishing ante-mortem altitude exposure or other physiologically similar oxygen deficiency situations.
Extrarenal Salt Excretion in Birds
Authors: Schmidt-Nielsen Knut , Jörgensen C. Barker , Osaki Humio
Published: December 2017

Investigations on cormorants ( Phalacrocorax auritus) gave no evidence to support the hypothesis that sea birds must drink sea water in order to cover their normal needs for water. When the birds were fed fresh fish the water content of the fish was more than adequate for the renal elimination of salts and nitrogen (uric acid). However, it was found that when given a salt load cormorants also employ an extrarenal mechanism for electrolyte elimination. Whether the load is imposed orally or by infusion of hypertonic NaCl solution, cormorants excrete a highly hypertonic liquid that drips out from the internal nares and collects at the tip of the beak, from which the birds shake the drops with a sudden jerk of the head. The concentration (500–600 mn NaCl) and the rate of secretion (up to 0.2 ml/min. in a 1.5-kg bird) are so high that with continuous secretion the entire NaCl content of the body could be eliminated in roughly 10 hours. The secretion contains practically only sodium and chloride in nearly equivalent amounts. The production of the nasal secretion is stimulated also by a nonelectrolytic osmotic load (sucrose), which indicates that the mechanism responds to general osmotic conditions rather than specifically to the sodium or chloride concentration of the plasma. The nasal secretion has been observed only after an osmotic load and never in fasting birds or after ingestion of fish or fresh water.
Intestinal Weight Changes in Hemorrhagic Shock
Authors: Johnson Paul C. , Selkurt Ewald E.
Published: December 2017

The weight of a segment of small intestine was continuously measured in dogs during a standardized hemorrhagic shock procedure. In 11 of 17 experiments intestinal weight decreased during hemorrhagic hypotension, while in the remaining 6 an unequivocal increase occurred. The magnitude and the direction of these changes were not correlated with changes in portal venous pressure. In late stages of hypotension a small rise in intestinal weight and in portal pressure was observed. On transfusion, intestinal weight increased further and in 13 of 17 experiments exceeded control levels. There was a small continuing increase of intestinal weight in most of these preparations as shock developed. This weight increase was correlated with the accumulation of sloughed mucosal cells and blood in the lumen of the intestine. In the four experiments in which intestinal weight did not reach control levels with reinfusion, there was a further reduction of weight as the animals went into shock. It is concluded that intravascular pooling of blood in the intestine is not a necessary feature of hemorrhagic shock.
Effect of the Bicarbonate Ion on Gastric Potential Difference
Authors: Dennis Warren H. , Rehm Warren S.
Published: December 2017

The effects on the gastric potential difference (P.D.) produced by the application of isotonic and diluted sodium bicarbonate solutions to the nonsecreting and secreting gastric mucosa of the dog are reported. These experiments were performed on anesthetized dogs using the chambered gastric segment preparation and were designed to test the hypothesis that the P.D. originates as the result of a bicarbonate ion gradient across the mucosa. Reversal of the bicarbonate gradient by replacing the 0.16 m NaCl mucosal fluid by 0.16 m NaHCO3 did not result in a change in the P.D. in the nonsecreting or secreting stomach. With 0.16 m NaHCO3 in contact with the mucosa there is a small net absorption of fluid. Considerations based on the laws of diffusion indicate that under these conditions the bicarbonate concentration in the pit and tubular lumina will reach appreciable magnitudes within a few minutes, and hence the origin of the P.D. cannot be ascribed to a bicarbonate ion gradient in the nonsecreting stomach.
Depot Fat Depletion Following Thermal Trauma
Authors: Milstein Seymour W. , Coalson Robert E.
Published: December 2017

The effects of moderate to lethal thermal injury by water scalding on the degree of peripheral body fat depletion in the rat were studied by the direct measurement of changes in the fatty acid content of a characteristic depot. Following a nonlethal burn, loss of fat and body weight was consistently less than in pair-fed controls for about 1 week. Later phases of this postburn period indicate that the normal capacity to deposit fat is not restored in burned rats during the interval when pair-fed mates reach control levels. In a lethal burn, fat depletion is rapid and extensive despite a normal intake of food that permits pair-fed controls to resume normal lipid economy.
Paper Electrophoresis of Serum Proteins in Control and Diabetic Rats
Authors: Peterson Ruth D. , Beatty Clarissa H.
Published: December 2017

A comparison of serum protein fractions (electrophoretic separation) between fed female control and alloxan diabetic rats indicates a decrease in percentage albumin and an increase in percentage α2-, ß- and γ-globulins. Total protein also decreased and so did the grams percentage albumin and α1-globulin, while the grams percentage ß-globulin rose. In the depancreatized series there was a decrease in both percentage and grams percentage albumin and α1-globulin and an increase in the percentage and grams percentage ß- and γ-globulins. With the exception of a rise in γ-globulin, sham operated rats showed no change in any category. Control male rats have higher α1 and lower γ-globulin values than female rats, but both male and female rats show the same changes following the production of diabetes by either alloxan administration or partial pancreatectomy. Fasting control or diabetic rats 24 hours produces no change in the serum protein patterns despite the disappearance of observable lipemia during the fast.
Pressure Characteristics of the Esophagus and Its Sphincters in Dogs
Authors: Schlegel Jerry F. , Code Charles F.
Published: December 2017

The pressure in the esophagus and its sphincters in seven well-trained, intact, healthy dogs was studied using three small water-filled polyethylene tubes attached to pressure transducers. To obtain resting pressures these tubes were withdrawn at intervals of 0.5–2.0 cm through the gastroesophageal junction, the esophagus and the pharyngoesophageal junction. Swallowing was induced by injection of water into the mouth or pharynx of the animals, and responses were recorded from selected sites. At rest, bands of elevated pressure about 2 cm wide were detected at the pharyngoesophageal and gastroesophageal junctions. The mean maximal pressures in the two zones were 20 and 6.9 cm of water, respectively. Pressure in the esophagus at rest was less than that in the gastric fundus. When swallowing began, the elevated pressure in the junctional zones decreased promptly, rose to high values as the peristaltic wave of deglutition swept into them, and then declined to resting levels. A peristaltic wave of high pressure swept through the esophagus with each swallow. These findings indicate that the junctional zones act as sphincters. Their behavior is identical to that in healthy human beings. The pressure pattern in the esophagus itself with swallowing is also the same in the two species, but in the dog the peristaltic wave moves faster and the rise of pressure is briefer. These differences may reflect the fact that the muscle of the dog's esophagus is entirely skeletal.
Na24 and K42 Exchange in Atrial Fibrillation
Authors: Klein R. L. , Holland W. C.
Published: December 2017

Changes in transmembrane flux of Na24 and K42 during acetylcholine (ACh) induced fibrillation have been investigated. At a mean atrial rate of 160/min., the efflux of K was estimated to be 3.45 pmole/cm2sec. With the onset of fibrillation the efflux reached a mean value of 9.37 pmole/cm2sec. This rate was 50% greater than the combined effects of ACh (8.0 x 10–4 gm/ml) and stimulation (1200/ min.) alone. With the onset of fibrillation a momentary increase of influx followed by a decrease to 1/20–1/40 the control was observed. ACh alone produced comparable effects. The rate of Na influx was increased 10–15 times by both ACh and fibrillation. Similar changes in Na efflux were noted but of a smaller magnitude. The change in fluxes noted are transient in nature with the rate returning rapidly to that of the control even though fibrillation continues. Upon cessation of the arrhythmia a momentary increase of K efflux was again observed. It is concluded that ACh and fibrillation increase the transmembrane flux of Na and K. With the present method the onset of fibrillation is best correlated with an increase of K efflux above a critical rate. Since these changes are transient, it appears that the initiation and maintenance of the arrhythmia are governed by separate physicochemical processes.
Blood Volumes of Dairy Calves Comparing Cr51-Tagged Red Blood Cells and T-1824 Plasma Dilution Methods
Authors: Stahl Perry Ruth , Dale Homer E.
Published: December 2017

In a repeated study on 17 dairy calves, T-1824 dye plasma dilution showed significantly higher blood volumes than were found by any other technique or computation method using Cr51-tagged red blood cells. Five blood samples taken at 20-minute intervals after injection showed consistent decrease in radioactivity count from the first to the last sample, indicating greater accuracy in radioactivity dilution regressed to zero time figures than in average counts of several postinjection samples. In vitro studies suggest a loss of Cr51 from red blood cells to plasma after saline washings are Cr-free. Percentage blood volumes computed from whole blood samples of calves injected with Cr51-tagged red blood cells decreased in a straight line relationship with increase of body weight. Percentage plasma and whole blood volumes estimated with the T-1824 dye technique decreased regularly with body weight increase until a second determination was made when there was a rapid rise nearly to the level of the smallest calves, followed by another regular decrease with increase in weight. It is suggested that repeated dye injections do not always measure the same space. Regressed values of five whole blood samples taken at 20-minute intervals after injection of Cr51 tagged red blood cells gave more consistent blood volume determinations than either the weighed red cells or the plasma dye dilutions of the same samples.
Circulatory Phenomena During Anoxia in the Newborn Lamb
Authors: Harned Herbert S. , Brandt Ira K. , Cooke Robert E.
Published: December 2017

Newborn lambs were delivered by hysterotomy, their respiratory passages occluded, and their umbilical cords ligated. Lead II electrocardiographs and aortic blood pressures were taken during the increasing asphyxia. Precipitous fall in heart rate resulting from heart block occurred within two minutes of cord ligation. Thereafter progressive fall in heart rate, systolic blood pressure, and pulse pressure occurred. In sequence, the electrocardiogram revealed heart block, return of slow sinus rhythm, lowering of T wave and shortening of QT interval, and terminal loss of P wave with development of bizarre broad QRS complex, low ST takeoff and loss of definition of the QS endpoint.
A Screening Procedure for Substances Which Inhibit Dextran Edema in the Rat
Authors: Stucki Jacob C. , Thompson Charles R.
Published: December 2017

Determination of foot volume by mercury displacement before and after the intraperitoneal administration of dextran to rats demonstrated that pronounced edema occurs one-half to three-fourths of an hour after dextran, reaches a maximum in 1 1/2 hours, and gradually subsides over the next several hours. Inhibiting substances prevent the edema entirely, reduce its severity or delay its appearance. A method was presented for screening compounds for ability to inhibit dextran edema. A dose-response curve developed for chlorpromazine suggests that the technique might also be suitable for quantitative bioassay. It was found that strongly vasoconstrictor adrenergic agents inhibited edema while adrenergic drugs with other predominating activities did not. Atropine, Dibenamine, morphine, reserpine, hydroxyzine and meprobamate were inactive. Chlorpromazine, the antihistaminics and anesthetic doses of phenobarbital were active. Cortisone and phenylbutazine were inactive but the salicylates were moderately active.
Mechanism of Emesis Following X-Irradiation
Authors: Wang S. C. , Renzi A. A. , Chinn H. I.
Published: December 2017

It was shown previously by Chinn and Wang that dogs exposed to 800 r total body irradiation vomited within 2 hours after completion of exposure. After chronic destruction of the chemoceptive emetic trigger zone, no dogs vomited within 2 hours of radiation. It was observed that these operated animals would vomit later throughout their period of survival. Visceral deafferentation alone (abdominal vagotomy and sympathectomy) did not prevent dogs from vomiting soon after irradiation or within several days. On the other hand, both acute and delayed emesis due to irradiation was not observed in dogs with chronic destruction of the chemoceptive trigger zone and abdominal visceral deafferentation. It appeared, therefore, that delayed vomiting following lethal total body irradiation was mediated through two mechanisms; the centrally located trigger zone, and the peripheral visceral afferent receptors of the vagus and sympathetic trunks.
Hyperthyroidism and the Dynamics of Distribution and Renal Excretion of Epinephrine in the Dog
Authors: Jones Richard T. , Blake William D.
Published: December 2017

Several parameters related to the dynamics of distribution and renal excretion of epinephrine were studied in anesthetized dogs before and during oral administration of thyroid extract. These parameters include: a) plasma concentration and renal excretion of epinephrine during constant infusion of l-epinephrine bitartrate, b) the rate of disappearance from plasma and volume of distribution of epinephrine, and c) the resting excretion of endogenous epinephrine before and during thyroid feeding. Except for an increase in the percentage of infused epinephrine excreted in the urine, there were essentially no changes in these parameters after feeding thyroid.
Carbohydrate Metabolism in Fed and Fasted Rats Exposed to an Altitude of 12,470 Feet
Authors: Timiras Paola S. , Hill Robert , Krum Alvin A. , Lis Adam W.
Published: December 2017

Blood sugar levels and the glycogen content of liver, heart, skeletal muscle, diaphragm and kidney of both fed and fasted sea level control rats were compared with those of fed and fasted rats (P) born at sea level and then exposed to an altitude of 12,470 feet for various periods of time, and with those of fed rats (F2) of the second filial generation born and maintained at altitude. In the P animals after short-term (24 and 72 hr.) exposure, liver, heart, muscle and diaphragm glycogen was markedly decreased in the fed animals as compared with the fed sea level controls, and markedly increased in the fasted hypoxic animals as compared with the fasted sea level controls. In fed P animals after long-term exposure, liver, heart, muscle and diaphragm glycogen was the same as in fed controls after 2 and 6 months at altitude, and became markedly lower than in the controls after 10 months. In the F2 rats, liver and muscle glycogen was markedly decreased when compared with the controls; in contrast, cardiac glycogen content was significantly higher in these F2 rats than in the controls. Changes were not observed in kidney glycogen. Hyperglycemia was observed in all P rats after 24 hours, and hypoglycemia after 72 hours at altitude. In the long-term experiments glycemia was the same in experimental (P and F2) and control rats.
Enhanced Sugar Uptake Fails to Simulate the Insulin Effect on Lipogenesis in the Isolated Perfused Rat Liver
Authors: Haft David E. , Miller Leon L.
Published: December 2017

Large quantities of glucose and fructose were infused without insulin into isolated livers of fasted normal and fed diabetic rats as a test of the widely accepted theory that the single primary role of insulin is to speed the entry of glucose into the cell. The liver disposed of large quantities of hexose in most cases without simultaneously increasing, as with insulin, the rate of incorporation of acetate-1-C14 into fatty acids. Much of the sugar was transformed to glycogen and CO2 without entering the pathways of fatty acid or ketone body synthesis, or influencing the conversion of acetate to these products. With livers of fasted normal rats, massive fructose infusion significantly inhibited urea formation and reduced the incorporation of acetate into glucose and plasma protein. The dissociation between carbohydrate balance and lipogenesis suggests that insulin has some primary action other than making more sugar available in metabolism. It is suggested that there is an anatomic separation of metabolic pathways in the liver, and that insulin serves to facilitate glucose transport between them.
Role of Zinc in Fertility and Fecundity in the Rat
Authors: Gunn Samuel A. , Gould Thelma Clark
Published: December 2017

It has been previously shown that zinc is present in high concentrations in the dorsolateral prostate of the rat (Mawson, C. A. and M. I. Fischer. Nature, London 167: 859, 1951) and that administered Zn65 is selectively taken up by that accessory sex gland (Gunn, S. A., T. C. Gould et al. Proc. Soc. Exper. Biol. & Med. 88: 556, 1955). This paper demonstrates that Zn65 traverses the entire female reproductive tract after ejaculation. The removal of large amounts of zinc from the ejaculate, by dorsolateral prostatectomy, has no deleterious effect on either fertility or fecundity.
Obligatory Function of a Continuous Flow of Normal Bile for Cholesterol Absorption
Authors: Ivy A. C. , Suzuki R. , Prasad C. Ram
Published: December 2017

Cholesterol-4-C14 and cholesterol-4-C14 stearate are absorbed into the chyle of the rat to an average extent of approximately 44%. They are not absorbed except in traces when the bile is diverted externally by means of a fistula. The artificial means used to date for restoring bile to the upper intestine have not resulted in the absorption of cholesterol or its stearate.
Nature of the Secretory Activity of the Mast Cell
Authors: Smith Douglas E.
Published: December 2017

In the tissues of the peritoneal cavity the mast cell appears to be the only cell capable of releasing histamine. Protamine sulfate and toluidine blue in certain concentrations in Tyrode's solution when injected intraperitoneally elicit the liberation of measurable amounts of histamine into the peritoneal fluid. Repeated injections of these substances cause repeated liberation of histamine. No visible changes in the mesenteric mast cells follow this treatment. It is concluded that secretion by the mast cell does not require cell disruption and death as much of the literature indicates but is merocrine in nature. The mast cell appears to be an endocrine cell which can continuously elaborate and release histamine in in response to appropriate stimulation.