bluuebunny/crossref_metadata_2025 huggingface dataset:
Presence of an Aldosterone Stimulating Substance in the Urine of Rats Deprived of Salt
Authors: Orti Eduardo , Ralli Elaine P. , Laken Bertram , Dumm Mary E.
Published: December 2017

These experiments are concerned with the study of a substance found in the urine of intact and adrenalectomized rats deprived of salt which when injected into intact hydrated rats caused a decreased excretion of sodium. As the substance was present in the urine of adrenalectomized rats, it obviously was not aldosterone. The substance responsible for sodium retention was thermolabile at pH 7, extractable with butanol and did not dialyze through a cellophane membrane. To determine whether the sodium retention by the assay rats was due to an increased excretion of aldosterone, the following experiment was done: feces of intact rats were collected during a control period. Feces were collected during a second period when the rats were injected daily with urine from adrenalectomized rats deprived of salt. Aldosterone was determined in the feces in each of these periods. The aldosterone excretion was greater during the period when the rats received the urines from the adrenalectomized rats deprived of salt. The authors conclude that the sodium-retaining activity of the urine of adrenalectomized rats deprived of salt was due to the presence of a substance capable of stimulating the adrenals of the intact rats to produce aldosterone. The substance was not present in purified ACTH.
Tracheal Constriction in the Dog
Authors: Loofbourrow G. N. , Wood William B. , Baird Irwin L.
Published: December 2017

Balloon and tambour recordings frequently revealed spontaneous, slow, rhythmic constrictions of tracheae in anesthetized dogs. Strong contractions were also induced in previously quiescent tracheae by asphyxia and, to a somewhat lesser degree, by rebreathing. Varying degrees of hypoventilation, achieved by regulation of the rate or stroke volume of a respiration pump (open-chest preparations) were, likewise, paralleled by corresponding degrees of tracheal constriction. Furthermore, a direct relation was demonstrated between the concentration of CO2 in the inspired air and the degree of tracheal constriction. The induced contractions could be prevented or, once produced, abruptly relaxed by sudden overinflation of the lungs. The significance of these mechanisms is briefly discussed.
Electrophoretic Study of Serum Proteins in Frog Red Leg Disease
Authors: Bucovaz Edsel , Kaplan Harold M.
Published: December 2017

Serum from frogs, Rana pipiens, was analyzed for quantitative changes in albumin and globulin fractions in red leg disease. Chemical fractionation plus dye elution and micro Kjeldahl analysis of the material obtained from the electrophoretic separations of the protein fractions, were used to determine the quantitative changes. Serum proteins significantly decreased in red leg disease, the globulin fractions showing a relatively greater decrease than that of albumin. The results are applicable to the diagnosis and management of an important and prevalent animal disease.
Effect of Chloride and Other Ions on the Activation of Bovine Plasminogen (Profibrinolysin)
Authors: Dalby Arthur , Mertz Edwin T.
Published: December 2017

Sodium chloride inhibits the activation of crude plasminogen (profibrinolysin) by streptokinase and human globulin, or urokinase. The plasmin yield obtained in the presence of sodium chloride is increased by the use of increased activator (streptokinase + human globulin) concentrations. Anions other than chloride ion produce smaller and varying amounts of inhibition. Calcium ions have either a stabilizing or activating effect. In the absence of salt, bovine plasminogen activates spontaneously. During chloroform-activation the time to the onset of activation is related to the concentration of salt present. Purified human plasminogen does not appear to be susceptible to sodium chloride inhibition.
Antagonism of Depressed Extracellular Potassium Levels Against Histamine Toxicity in Mice
Authors: Macmillan William H.
Published: December 2017

The lethality of histamine was studied in three groups of 110 CFw mice fed low, normal and high potassium content diets, respectively, for 5 weeks. The plasma potassium levels of the three groups on the 34th day were 3.2 ± 0.4 mEq K+/l. for the mice on the low potassium content, 5.7 ± 0.8 mEq K+/l. for the group on normal diet, and 5.4 ± 0.4 mEq K+/l. for the group on high potassium diet. The ld50's and 19/20 confidence limits for the respective groups to intravenous histamine were 240 (220.2–261.6) mg/kg, 189 (170.3–209.8) mg/kg, and 155 (142.5–168.6) mg/kg. These data indicate that a reduction in total body potassium offers a protective action against the production of histamine death in mice and confirm earlier reports that the presence of potassium in this species enhances the toxic effects of histamine. The results obtained cannot be explained on the basis of delayed circulation time, renal or adrenal pathology; however, they suggest a possible mechanism to explain the protective action of fasting against histamine toxicity in this species.
Effect of Local X-Irradiation on Albumen Formation by the Hen's Oviduct
Authors: Smith Arthur H. , Winget Charles M. , Hage Theodore J.
Published: December 2017

X-irradiation of the surgically exposed oviduct of the hen reduces the formation of albumen dry matter (which is composed essentially of protein). Over a dosage range of 0–4000 r, the irradiation effect is logarithmically related to the dose, with the albumen (dry basis) formation being reduced 40% at 4000 r. At higher doses (5000 r) irreversible changes apparently take place, since very few birds so treated return to egg production. Radioinhibition of albumen formation requires direct irradiation of the oviduct magnum tissue and, once established, appears to be more or less permanent. The functional status of the magnum tissue, relative to albumen secretion, at the time of irradiation does not appear to influence the result.
A New Explanation for the Osmotic Activity and Ionic Composition of Gastric Juice
Authors: Rehm Warren S. , Dennis Warren H. , Brodsky William A.
Published: December 2017

In an attempt to extend a previously proposed theory of gastric HCl production, the possibility is considered that the surface epithelial cells secrete H+ ions and the parietal cells Cl– ions and water. It is postulated that water is transported as a result of its chemical potential gradient between the interstitial fluid and the canalicular lumen of the parietal cells. It is shown that this scheme can quantitatively explain, without further postulates, the high normalities of secretion found in the glycine experiments of Teorell. However, the scheme predicts for pure gastric juice a higher osmotic pressure than that found. Furthermore, the scheme does not offer an explanation for the presence of the other inorganic ions of gastric juice. In an attempt to account for the observed osmotic pressure and the inorganic ion content of gastric juice, the implications are developed of the assumption that the Na+ ions, K+ ions and some of the secreted Cl– ions are transported across the mucosa in the direction of their electrochemical potential gradients. It is shown that the resulting scheme can account for the composition and osmotic pressure of gastric juice at least as well as any of the schemes proposed by other workers. The implications of the present scheme with respect to the problem of the production of hypertonic and hypotonic secretions are discussed.
Dibenzyline Protection Against Shock and Preservation of Hepatic Ferritin Systems
Authors: Baez Silvio , Srikantia S. G. , Burack Bernard
Published: December 2017

Pretreatment with Dibenzyline, an adrenergic blocking agent, markedly increased the survival rate of normal, arenal or adrenalectomized rats subjected to drum trauma, and of normal rats subjected to prolonged hemorrhagic hypotension. In the latter a larger residual circulating blood volume was not responsible for the increased survival since average maximal blood loss was equal in treated and control rats. Congestion of the liver and gut, regularly seen in the controls, was notably absent in the Dibenzyline-protected rats. Direct microscopic observation of the terminal vascular bed in the mesoappendix, throughout the hemorrhagic procedure, revealed earlier appearance of decompensatory changes and increased vascular fragility in the controls. In livers removed at the end of the hemorrhagic and traumatic procedures, ferritin systems were preserved in treated rats, in contrast to their deterioration in controls. It is suggested that the protection conferred by pretreatment with Dibenzyline may not be due solely to its adrenergic blocking properties, but in part to a direct cellular action in the liver, exemplified by its in vitro protection of the ferritin systems against hypoxic damage.
Acetylcholine Content in the Stretched Wall of Intestine
Authors: Ikeda M. , Hayama T. , Chujyo N. , Hoshi A.
Published: December 2017

Acetylcholine content of the guinea pig ileum and the effect on it of the circumferential stretching of the intestinal wall were studied. The total acetylcholine content decreased immediately after stretching, which effect was inhibited by eserine. Release of acetylcholine and its enzymatic destruction may be responsible for the decrease of acetylcholine. Changes in potassium content of the environmental fluid of the intestine were also studied. The results suggest that the circumferential stretching augments the loss of potassium from the tissue, and this effect of stretching was enhanced by eserine.
Effect of Surgical Trauma, ACTH and Adrenal Cortical Hormones on Electrolytes, Water Balance and Gluconeogenesis in Male Chickens
Authors: Brown Keith I. , Brown Dorothy J. , Meyer R. K.
Published: December 2017

Ten-week-old gray leghorn cockerels with ureters surgically exteriorized so that 24-hour samples of feces free urine could be collected were treated with DCA, cortisone acetate and ACTH. The stress of surgically exteriorizing the ureters produced reduction in weight gains and an increased excretion of electrolytes and nitrogenous wastes on days 3 and 4 following the surgery. In addition there was some adrenal hypertrophy. DCA treatment resulted in polyuria, polydipsia, sodium and potassium retention, and an increase in thiocyanate space. Cortisone acetate caused loss in weight, polyuria and increased excretion of sodium, potassium, total nitrogen and uric acid. There was a slight decrease in thiocyanate space and a temporary increase in liver glycogen. ACTH prevented normal weight gains and caused an increase in uric acid and total nitrogen excretion along with an increase in liver glycogen. Although there was no change in electrolyte excretion the sodium and potassium presumed to be released by tissue catabolism made it appear probable that there was retention of electrolytes by the kidneys. ACTH caused a small amount of adrenal hypertrophy. These data show that the hormones secreted by the adrenal of the bird produce effects similar to those in the mammal. The suggestion was made that the bird adrenal may be relatively autonomous and that it, therefore, functions at a relatively high level even in the absence of the anterior pituitary. It was also suggested that the ratio of adrenal steroids secreted, such as aldosterone, corticosterone, and dehydrocorticosterone, may vary according to the physiological needs of the animal.
Role of Bradycardia and Cold per se in Increasing Mechanical Efficiency of Hypothermic Heart
Authors: Badeer Henry , Khachadurian Avedis
Published: December 2017

The relative influence of bradycardia and of cold per se on the oxygen consumption and mechanical efficiency of the dog heart was investigated in the modified heart-lung preparation (11 experiments). Myocardial oxygen uptake was determined under constant arterial pressure and cardiac output in a) normothermia, b) normothermia with bradycardia induced by a cold thermode on the pacemaker, and c) hypothermia producing the same bradycardia as in ( b). At 36.8°C with a rate of 153 beats/min. the efficiency was 8.5% ± 0.3(S.E.), whereas with a rate of 110/min. efficiency was 9.1% ± 0.4(S.E.), a change that is statistically not significant. In hypothermia of 31.5°C with a rate of 110/min. the efficiency was 10.8% ± 0.3(S.E.), an increase that is statistically significant. Performing the same stroke work the hypothermic myocardium consumed less oxygen than the normothermic. It is concluded that the metabolic effect of cold per se is the chief factor responsible for increasing the mechanical efficiency of the hypothermic heart when pressure-volume work is kept constant.
Effects of Oral Chlortetracycline on Diarrhea and on the Dry Weights of Cleaned Intestinal Organs in Rats Fed Two Different Diets
Authors: Lee Helen Wing-Tsit , Moinuddin Jessie Fischer
Published: December 2017

Feeding chlortetracycline in the diet reduced the total number of fecal discharges both in rats fed a basal cornstarch diet and in rats fed a 25% lactose diet. Diarrhea occurred in many of the lactose-fed rats during the first 2 weeks, but neither the ratio of diarrheal discharges to total discharges nor recovery from the diarrhea was affected by chlortetracycline. Chlortetracycline did not significantly alter the absolute weight of the small intestine or of the colon plus rectum in rats fed either diet. However, it decreased the small intestine weight:body weight ratio in the lactose-fed rats and decreased the colon plus rectum weight:body weight ratio in rats fed both diets. It increased the absolute and relative weights of the cecum in the cornstarch-fed rats, but did not affect the enlarged cecum in the lactose-fed rats. The small gut length was not altered by chlortetracycline, but the length was increased by the lactose diet (with or without chlortetracycline) compared to the cornstarch diet without chlortetracycline.
Changes in the Diameter of Apical Dendrites During Spreading Depression
Authors: Van Harreveld A.
Published: December 2017

One of the concomitants of spreading depression is a considerable increase in the cortical electrical resistance. After cortical asphyxiation a similar resistance increase has been observed. It was postulated that these resistance increases are due to a transport of ions from the extracellular compartment into the cortical cells and fibers. To maintain osmotic equilibrium this has to be accompanied by water transport causing a swelling of cortical elements. A swelling of nerve cells and apical dendrites has been found to accompany the asphyxial resistance increase. In the present paper the diameters of apical dendrites during spreading depression were compared with the dendritic diameters in the contralateral hemisphere where no spreading depression was in progress. A mean increase in diameter of 17% was observed during spreading depression. No swelling of the apical dendrites was observed in the retrosplenial area which is not normally invaded by spreading depression. These findings support the notion that the resistance change during spreading depression is due to the same mechanism as that after cortical asphyxiation, namely to an ion transport accompanied by a water movement from extra- into intracellular spaces.
Atropine Depression of Food and Water Intake in the Rat
Authors: Schmidt H. , Moak S. J. , Van Meter W. G.
Published: December 2017

The effect of atropine upon food and water intake was investigated in the albino rat. Dosages up to approximately 7 mg/kg of atropine sulfate were used in two experiments upon water intake and an experiment upon food intake. Atropine depressed both food and water intake to some limiting value. Eating was reduced to a greater extent than was drinking relative to the control conditions. The experimental arrangements obviated the possibility that the depression of water intake, by atropine, is contingent upon reduced food intake, while the procedure used for studying food intake did not exclude the possibility of the observed reduction of eating being dependent upon reduced drinking. However, the relatively greater reduction of eating as compared with drinking suggests that such a dependency will not account for the total effect.
Increase in Amylase of Rat Submaxillary Gland in Response to Acetylcholine or Feeding
Authors: Schneyer L. H. , Schneyer C. A.
Published: December 2017

Acetylcholine, administered subcutaneously, or normal feeding following a period of food withdrawal leads to rapid and appreciable amylase accumulation in the submaxillary-sublingual gland of the rat. This effect does not appear to be contingent on prior depletion of gland enzyme stores and is completely prevented by administration of atropine prior to and during the period of stimulation. The effects of stimulation by acetylcholine or feeding thus appear comparable to that by pilocarpine and are consistent with the thesis that the parasympathetic nervous system, in the case of this gland complex at least, plays a role, independent of its effect on secretion, in regulating the process of enzyme synthesis.
Effects of l-Epinephrine and l-Norepinephrine on Foot Vasculature After Sympathectomy in Dogs
Authors: Ederstrom H. E. , Vergeer T. , Oppelt W. W.
Published: December 2017

The acutely sympathectomized foot of dogs was less responsive to intra-arterially infused l-epinephrine and l-norepinephrine than the opposite control leg, as indicated by blood flow in the saphenous veins. In chronically sympathectomized legs, blood flow methods failed to disclose any increased sensitivity to intra-arterially or or intravenously infused epinephrine and norepinephrine. The degree of vasoconstriction induced by the two drugs was about equal, as was the rise in mean blood pressure. Blood vessel strips removed from the operated and control legs and tested in vitro responded differently to epinephrine and norepinephrine in that chronically sympathectomized vessels were twice as responsive to the two amines as were the controls. Chronic lumbar sympathectomy undoubtedly produced sensitivity changes in the leg vasculature, and while this was not demonstrable in the intact preparation it could be shown by in vitro studies.
Regional Blood Flow by Fractional Distribution of Indicators
Authors: Sapirstein Leo A.
Published: December 2017

K42 Cl, Rb86Cl and iodoantipyrine (I131) were given in single intravenous injections to rats. The isotope content of the organs and the arterial blood concentrations were studied as a function of time. K42Cl and Rb86Cl reached a stable level in all organs other than the brain in 6–9 seconds and maintained this level until 64 seconds. The arterial concentration curves for the isotopes showed that the injected dose was almost completely transferred into the arterial system at about 6–8 seconds. The isotopes showed subsequent recirculation amounting to about 40% of the original dose between the first recirculation and 64 seconds. The organs which displayed stability during the period of recirculation must have had extraction ratios from zero time less than 1.00 but equal to that of the whole body. The fractional uptake of indicator by such organs must therefore have been equal to their blood flow fraction of the cardiac output. The brain reached its maximum content of Rb86 and K42 in 5–6 seconds; both isotopes then disappeared rapidly. The brain was thus shown to have a lower extraction ratio toward these isotopes than the body as a whole; its flow fraction could not therefore be measured by their use. Most organs failed to show stability of their iodoantipyrine content between 9 and 64 seconds; this indicator is not suitable for the measurement of the flow fraction of such organs. By combining values for the cardiac output and the fractional uptake of K42 in dog organs, regional blood flow values were obtained. For those other organs where flow values by other methods are available, the agreement was good. The following blood flow values were obtained in the major organs of the dog: Heart (coronary flow), 1.0 ml/gm/min.; kidney, 3.0 ml/gm/min.; liver, 1.2 ml/gm/min. (0.4 ml/gm/min. hepatic artery, 0.8 ml/gm/min. portal vein); skin, 0.07 ml/gm/min.
Force-Velocity Relationship of Vitamin E-Deficient Skeletal Muscle
Authors: Schottelius B. A. , Schottelius D. D.
Published: December 2017

Force-velocity curves were derived for gastrocnemius muscles from guinea pigs maintained on vitamin E-deficient and vitamin E-supplemented diets of 15 and 30 days duration. It was noted that the deficient diet even when supplemented with seemingly large amounts of vitamin E was not adequate to promote optimal growth. Velocities of contraction were diminished in gastrocnemii of animals on the deficiency regimen for 15 and 30 days, however, the differences from control values attained statistical significance at the longer duration. The constants of Hill's characteristic equation relating the rate of total energy production in isotonic contractions were calculated and compared. Although the absolute values of the thermal constant, a, and rate constant, b, of control and experimental muscles exhibited a statistically significant difference only in the 30-day studies, the relative values of the thermal constant in deficient muscles were significantly greater at both 15 and 30 days.
Role of the Anterior Pituitary in the Development of a Fatty Liver
Authors: Wool Ira G. , Goldstein M. S.
Published: December 2017

This study was undertaken to determine whether a fat mobilizing factor from the anterior pituitary is essential to the development of a fatty liver. The method employed was the administration of ethionine, an antimetabolite of methionine, to fasted female rats. Hypophysectomy led to a marked impairment in the ability to accumulate hepatic lipids. Cortisone alone or combined with thyroxine failed to restore this defect. Epinephrine administered to cortisone-maintained hypophysectomized rats led to the development of a fatty liver. While lipid accumulation in the liver can precede in the absence of a specific anterior pituitary fat mobilizing factor, the quantitative aspects do not exclude a possible physiological role for such a principle.
Effect of Vagotomy on Pancreatic Secretion
Authors: Tankel Henry I. , Hollander Franklin
Published: December 2017

This investigation was concerned primarily with the effect of vagotomy on the secretory responses of the canine pancreas. Quantitative collections of uncontaminated pancreatic juice were effected by use of chronic preparations, provided with a cannula-closed duodenostomy (Thomas technique) and a gastrostomy to prevent interference by the HCl-secretin mechanism. Vagotomy had no significant effect on the basal pancreatic secretion of water (volume-rate) or bicarbonate. When secretion was induced by administration of secretin or histamine, vagotomy was followed by an increase in both volume and HCO3, although the rises were statistically significant in only two of the four dogs studied. It is concluded that the vagus appears to play a considerable inhibitory role in the regulation of water and electrolyte outputs in exogenously stimulated pancreatic secretion, but not in the basal secretion.
Effect of a New Steroid on Phospholipid Metabolism of the Chick
Authors: Ranney R. E. , Weiss Sally E.
Published: December 2017

The incorporation of P32 into the phospholipid of plasma, liver, kidney and aorta of chicks treated with a synthetic steroid, methoxy-methyl-estratriene-diol (SC-6924), was measured. In the absence of the liver there was virtually no new plasma phospholipid formed and neither kidney nor aorta phospholipid synthesis was affected by the steroid treatment. Administration of SC-6924 enhanced incorporation of the isotope into the phospholipids of liver and plasma of treated birds. Specific activity-time curves confirmed the hypothesis that liver phospholipid is the precursor of plasma phospholipid. It was apparent that the induced modification of lipid metabolism involved not only hepatic synthetic mechanisms but also catabolic systems concerned with phospholopid metabolism.
Observations on Epinephrine and Glucagon-Induced Glycogenolysis and Potassium Loss in the Isolated Perfused Frog Liver
Authors: Craig Albert B.
Published: December 2017

In the isolated perfused frog liver, epinephrine and glucagon produced potassium and glucose losses. Potassium loss preceded the glucose loss and the potassium loss ceased as glucose loss reached a maximum rate. After stimulation and after glucose loss begins to decrease, the liver was able to regain potassium. Both the potassium and glucose losses were influenced by the potassium concentration of the perfusion medium. Potassium loss was accompanied by sodium loss. The dose response to epinephrine in this preparation was similar for both the potassium loss and glycogenolysis.
Increased Muscle Permeability to Aldolase Produced by Depolarization and by Metabolic Inhibitors
Authors: Zierler Kenneth L.
Published: December 2017

Aldolase leak from rat peroneus longus muscle is assumed to occur by diffusion and its magnitude is taken to be an index of membrane permeability. Aldolase efflux is increased by high external K concentration, presumably owing to membrane depolarization. Mg lack may be slightly effective. Metabolic inhibitors, iodoacetate, dinitrophenol or cyanide, markedly increase aldolase efflux. These observations, with earlier ones on the effects of anoxia and of glucose lack, suggest that muscle membrane is labile, its permeability linked to cellular metabolism. A dynamic model of muscle membrane is proposed in which sites through which diffusion can occur ripple over the cell surface.
Renal Response to Changes in Nitrogen Metabolism in Sheep
Authors: Schmidt-Nielsen Bodil , Osaki Humio
Published: December 2017

The camel has been found to be able to regulate the urea excretion on the renal tubular level. The same was demonstrated in sheep. Lactating or growing sheep, when placed on a low protein diet, decreased the fraction of filtered urea appearing in the urine to very low values. The low urea excretion was characterized by a urea U/P ratio not exceeding 5–7 even at low urine flows. The degree to which urea is concentrated in the urine over the plasma at low urine flows was found to be a good indicator of the regulatory state of the kidney. Changes in this regulatory state could be brought about within approximately one hour. A sudden lowering of the maximum urea U/P was found after a deficient protein-free diet was supplemented with grain. Conversely, a urea infusion raised the maximum urea U/P ratio abruptly in a sheep maintained on a low protein intake. The effect of administration of hydrocortisone or ACTH was studied to determine if these hormones could have a direct effect upon the regulatory state of the kidney. No acute effect was observed. Prolonged administration had in some instances a renal effect. The effect, however, was probably secondary to changes in nitrogen metabolism. The main results are that the excretion of urea is regulated by the renal tubule, that changes in the regulation can take place rapidly following a suitable stimulus, and that these changes are independent of plasma urea level.
Absence of a General Critical Closing Pressure in the Isolated Perfused Lung
Authors: Gilbert Robert P. , Hinshaw Lerner B. , Kuida Hiroshi , Visscher Maurice B.
Published: December 2017

Evidence for a critical closing pressure in the lung blood vessels is contradictory. Some of it is obscured by the use of a positive expiratory pressure during ventilation of the lungs. In the present study, the isolated lungs of dogs or cats were perfused with homologous blood or dextran, and the pressure gradient was measured while the lung weight was followed with a strain-gauge weighing device. Expiratory pressure was allowed to fall to atmospheric levels. Pressure-flow curves were obtained which included points for low flows. In addition, the pressure decay curve and rate of weight loss (venous outflow) were followed after arrest of the arterial inflow. It was found that at low flows the pressure-flow curve turned towards the origin. When the arterial inflow was completely stopped the pressure drop fell to zero (0.1 mm Hg) as the venous outflow approached zero. It was concluded that a general critical closing pressure is not evident in the isolated perfused dog or cat lung. The findings of previous workers concerning the general shape of the pressure-flow curve for the lung were confirmed.
Effects of Changes in Intraluminal Pressure on Inotropic and Chronotropic Responses of Isolated Mammalian Hearts
Authors: Pathak C. L.
Published: December 2017

The effect of increasing the intraluminal pressure in the right heart on the activity of isolated perfused dog hearts and the effect of increasing the intraluminal pressure on the activity of isolated right atria of dogs, rabbits, guinea pigs and albino rats have been studied. It has been observed that there is a direct relationship between the magnitude of intraluminal right atrial pressure and the inotropic and chronotropic responses of the whole heart and right atrium up to certain critical pressures (5–15 mm Hg). Some modifications in this behavior of the hearts due to repeated changes in the intraluminal pressure have also been described. It has been suggested that stretch of the cardiac tissue due to increased intraluminal pressure may cause alterations in membrane metabolism at the pacemaker.
Biochemical and Electroencephalographic Changes in the Brain of Rabbits Injected With 5-Hydroxytryptophan (Influence of Chlorpromazine Premedication)
Authors: Costa E. , Rinaldi F.
Published: December 2017

After the administration of 5HTP (75 mg/kg i.v.) to rabbits, the serotonin concentration increased significantly in the telencephalon, the hippocampus, the medulla-pons and most of all in the midbrain; in the cerebellum the increase was much less. The augmentation of serotonin concentration occurred during the first 2 hours after the injection of 5HTP and reached its maximum at the 2nd hour. At the 3rd hour a decline toward more normal values was observed. During the first 2 hours after the injection of 5HTP behavioral changes (excitation with unresponsiveness to alarming stimuli), as well as EEG changes (monorhythmic diffuse high voltage activity; disappearance of cortical fast rhythms and hippocampal theta waves followed by a generalized depression of voltage) occurred. The administration of chlorpromazine alone does not modify the serotonin content of the brain. But in the various brain parts of chlorpromazine pretreated animals the administration of 5HTP caused increases of serotonin concentration which were of greater magnitude and longer duration than those found in animals treated with only 5HTP. When animals were pretreated with chlorpromazine, the injection of 5HTP did not produce behavioral hyperexcitation and the animals did not arouse from chlorpromazine tranquilization.
Relative Resistance to the Hypertensive Effects of Desoxycorticosterone During Active Phase of Renal Compensatory Hypertrophy
Authors: Hall C. E. , Hall O.
Published: December 2017

An attempt was made to ascertain the circumstances under which unilateral nephrectomy maximally sensitized rats to hypertensive cardiovascular disease induced by desoxycorticosterone acetate in the presence of augmented NACl intake. The experiments showed that animals in which hormone treatment was delayed until 2 weeks after uninephrectomy were much more sensitive than animals in which hormone treatment was begun on the day of kidney removal. This was indicated by earlier onset and greater severity of hypertension; by a larger percentage of animals in such groups being affected, and by a greater incidence and severity of cardiovascular lesions in the former as compared with the latter. The much greater kidney size of the former clearly makes it difficult to ascribe the greater sensitivity to a reduction in renal mass as such. It is thought that during active compensatory renal hypertrophy the renal tubules are probably less responsive to the action of the hormone and therefore less prone to develop sodium retention and hence hypertension.
Effect of Hepatic Vitamin A and Carotene Concentration on the Biological Value of Carotene in the Bovine
Authors: Page H. M. , Erwin E. S. , Varnell T. R. , Roubicek C. B.
Published: December 2017

Steers were individually fed varying amounts of carotene in accord to body weight for 110 days. Hepatic carotene retention did not prove to be indicative of carotene intake. While 7.54 mg of dietary carotene was necessary to maintain initial hepatic vitamin A content, liver vitamin A storage was not a linear function of the amount of carotene consumed. All animals were then fed similar amounts of carotene based on body weight. While vitamin A retention was related to previous carotene intake as well as the initial liver vitamin A content, hepatic carotene retention was related only to the initial liver carotene content. In a second study, heifers were pretreated with varying amounts of preformed vitamin A and fed a carotene-vitamin A free ration for 61 days. The initial liver concentration of vitamin A greatly influenced the magnitude of liver vitamin A expenditure. However, all animals lost a similar percentage of their initial hepatic vitamin A content.
Effect of Large Doses of Head Irradiation in Dogs
Authors: Peng Ming-Tsung , Chien Shu , Gregersen Magnus I.
Published: December 2017

Dogs in which the head was x-irradiated with 23,500 r survived from 14 to 28 hours. The chief neurological signs were disturbance of equilibrium and extensor rigidity. Throughout the whole postirradiation course, the blood volume showed very little change. Arterial pressure, heart rate and respiratory rate remained essentially unchanged until about 1 hour before death. The carotid sinus reflex did not change until 30–60 minutes before death, but then deteriorated rapidly. Generally, the respiratory response to cyanide injection was still present after the disappearance of the carotid sinus reflex. At the terminal stage, the pressor response of the medullary vasomotor center to electrical stimulation decreased in parallel to that of the carotid sinus reflex. The vital centers in the medulla oblongata are directly damaged by large doses of x-irradiation. The failure of respiration is the cause of death.
Penetration of Anions Through Frog Skin
Authors: Mullins L. J.
Published: December 2017

A feedback amplifier-servomotor circuit is described for holding frog skins at short-circuit. Under conditions of zero potential difference across the skin, the rate of transfer of radioactive chloride and iodide ions have been compared. Chloride crosses the skin about 2.5 times as fast as iodide when both sides of the skin are bathed with Ringer's solution. Iodide appears to cross somewhat more rapidly if both sides of the skin are bathed with an iodide-Ringer's solution.
Electrical Properties of Wall of Endolymphatic Space of the Cochlea (Guinea Pig)
Authors: Misrahy George A. , Hildreth Kenneth M. , Shinabarger Edward W. , Gannon William J.
Published: December 2017

By measuring potential drop produced by a constant current across the partition between scala media and scala tympani the average resistance of this partition was found to be 4700 ohms at the round window, 3500 ohms at the first turn, 1200 ohms at the second turn and 600 ohms at the third turn. Just preceding or simultaneously with a drop in d.c. potential there was a drop in resistance in response to loud sound. Recovery of the resistance preceded recovery of d.c. potential. Anoxia first lowered d.c. potential, then resistance. Both appeared to recover at nearly the same time. Destruction of the fourth, third and second cochlear turns did not affect d.c. potential or microphonics in scala media recorded from the first turn through the round window. Both were abolished upon destruction of the first turn. No spread of current was found from one turn to another. Implications of these results are discussed.
Defects in Optokinetic Afternystagmus in Lesions of the Brain Stem
Authors: Shanzer S. , Teng P. , Krieger H. P. , Bender M. B.
Published: December 2017

Optokinetic afternystagmus (OKAN) was investigated in 50 rhesus monkeys. All had electrolytic lesions in the brain stem. Twenty-two of them showed a unilateral defect in OKAN. This defect was correlated with the location of the lesion in the oculomotor pathways. Twenty-eight monkeys showed no such defect. In absence of other measurable signs OKAN can serve as a sensitive index of a type of oculomotor dysfunction.
Motivational and Perceptual Aspects of Subcortical Stimulation in Cats
Authors: Nielson Harold C. , Doty Robert W. , Rutledge Lester T.
Published: December 2017

Reports of others that animals will seek electrical stimulation of certain regions of the central nervous system are confirmed. A method is presented whereby these ‘motivational’ aspects of central stimulation can be analyzed and shown to be capable of change by training and to have a different threshold from the animal's ‘perception’ of this stimulation. Cats were trained to press a bar to receive pellets of meat. When each bar-press was accompanied by stimulation through electrodes implanted in the caudate nucleus or anterior hypothalamus, the animals continued pressing. If the press was paired with stimulation of the septal or habenular regions, pressing was abolished. Foot-shock paired with pressing also produced avoidance but pairing with a startling buzzer did not. Caudatal stimulation of 0.2 ma, 50/sec., 2-msec. pulses, was adequate as conditional stimulus to establish conditioned foreleg flexions to avoid an electric shock. Subsequent to the latter training two animals would no longer press the bar if pressing resulted in caudatal stimulation. Other cats would press as often as 1000 times in a 20-minute period to obtain caudatal stimulation if it were allowed at rapid rates and intensities five times that required to evoke conditioned flexion reflexes. The evidence suggests that avidity develops for stimulation of certain neural structures only if the stimulus is adequate to initiate some form of excessive, seizure-like activity.
Role of Neurohumors in the Action of the Adrenal Cortical Steroids: Protein Mobilization
Authors: Wool Ira G. , Goldstein M. S.
Published: December 2017

Phlorhizin diabetes was induced in rats to promote nitrogen mobilization. Adrenalectomy reduced nitrogen excretion and small permissive amounts of cortical steroids restored this capacity. Because of the previously demonstrated functional relationship between the autonomic-medullary neurohumors and the adrenal cortical steroids, the sympathetic amines were examined for their possible role as the effector agents in protein mobilization. The results were uniformly negative, indicating that the adrenal steroids support some agency other than the epinephrines in promoting nitrogen mobilization.
Effect of Pentobarbital and Atropine on Arterial Pressure Response to Ganglion Blocking Agents
Authors: Page Irvine H. , McCubbin J. W.
Published: December 2017

Pentobarbital anesthesia produces an important change in the dog's arterial pressure response to TEAC. Without anesthesia, the response, instead of being sharply depressor, is characteristically pressor, or biphasic and mainly pressor. Only occasionally is it depressor. Small doses of TEAC more often elicited depressor responses than did large ones. Mecamylamine, hexamethonium and chlorisondamine usually also failed to cause appreciable lowering of arterial pressure in unanesthetized dogs, but did not show as much pressor activity as did TEAC. Responses to TEAC in hypertensive conscious man showed considerable variability, but the overall pattern of response tended more to resemble that of anesthetized than that of unanesthetized dogs. Atropine caused narrowing of pulse pressure, tachycardia, little change in mean pressure, and the response to TEAC to become mainly depressor—though not to the same degree as did pentobarbital. The greatly augmented depressor activity of ganglion blocking agents after pentobarbital anesthesia probably depends in large part upon nearly complete inhibition of parasympathetic cardioinhibitory activity by the anesthetic agent, and upon partial suppression of sympathetic compensatory reflexes by the ganglion blocking action of pentobarbital. Cardiovascular reactivity measurements are closely dependent on the conditions of the experiment and anesthesia is one of the most important of these conditions.
Cardiac Output in Early Phase of Blast Injury in Rabbits
Authors: Clemedson Carl-Johan , Hultman Holter
Published: December 2017

Changes in cardiac output measured by the direct Fick method were studied in rabbits which had been exposed to high explosive shock waves in a detonation chamber. The maximum reflection overpressure in the shock waves ranged between 3.5 and 11 atm. for the different weights of charge used. In all exposed animals there was a decrease in cardiac output already 5 minutes after the detonation. The degree of reduction of the output of the heart is directly proportional to the weight of charge used, i.e. of the force of the detonation. The cardiac output and the lung hemorrhages seem to be two parallel effects of the pressure of the shock wave with no mutual interference between the two. The cause of the reduction seem to be complex, but the direct action of the shock wave on the heart is supposed to play a significant role. The bradycardia existing during the 1st minute after the detonation was found to be of no importance for the reduction of the output of the heart.
Reticular Formation Interactions
Authors: Koizumi K. , Ushiyama J. , Brooks C. McC.
Published: December 2017

A comparison was made of the effects on the monosynaptic reflex and on unit discharge within the reticular formation of stimulating the reticular formation, the dentate nuclei, the paramedian lobe and crus I and II of the cerebellum, the caudate nucleus and the auditory cortex. Many reticular formation units were unaffected by the stimuli employed. The auditory cortex and caudate nucleus evoked activity in some reticular formation units without perceptible action on the monosynaptic reflex response. Stimulation of the cerebellum and dentate nuclei affected the reflex and was additive to the effects of reticular formation excitation. Cerebellar stimulation evoked activity in some reticular formation units, and inhibited that of others which were likewise inhibited by a variety of sensory stimuli. Some units were affected by one stimulus modality only but a few appeared to be under the influence of two centers, i.e. auditory cortex stimulation inhibited activity while caudate nucleus stimulation caused an augmentation of active firing. Direct stimulation of the reticular formation evoked shorter lasting activity of the elements in reticular formation than did stimulation of peripheral structures. The latencies of cerebellar effects on the reticular formation were often very long but the latencies of potentials evoked in the cerebellum by reticular formation stimuli were short.
Cortico-Spinal Responsiveness During EEG Arousal in the Cat
Authors: Zanchetti Alberto , Brookhart John M.
Published: December 2017

This study considers the possibility that the greater mobility of the mammal during aroused alertness is due to an elevation of excitability of cortical neurons giving rise to cortico-spinal fibers. Responsiveness of this neuronal population to electrical excitation of the cerebral cortex was measured during periods of spindle bursts in the EEG, during interspindle lulls, and during electrocorticographic arousal initiated by olfactory or by hypothalamic stimulation. Responsiveness during spindle waves varied widely; during interspindle lulls and during induced arousal responsiveness was stable. There were no significant differences between the central tendencies of responsiveness in these three conditions. It is concluded that the unknown cortical mechanisms activated by the change from the comatose to the aroused condition of the EEG do not involve an alteration in the state of corticospinal neurons or their associated cortical interneurons.
Utilization of Glucose, Fructose and Galactose by Scorbutic Guinea Pigs
Authors: Banerjee Sachchidananda , Divakaran Eswaramangalath Ramankutty
Published: December 2017

The utilization of glucose, fructose and galactose was studied in scorbutic and paired fed normal guinea pigs by performing tolerance tests with these sugars and by determining the glycogen contents of the liver and skeletal muscle of these animals. After feeding glucose the blood glucose of scorbutic guinea pigs attained a markedly higher peak and showed a delayed fall compared with that of normal guinea pigs. Ingestion of fructose was accompanied by an appreciable rise in the true blood glucose of scorbutic and normal guinea pigs. Administration of galactose did not elicit any such elevation of blood glucose. The amounts of fructose and galactose found in the blood of scorbutic guinea pigs at different intervals after administration of the respective hexoses were essentially the same as in normal guinea pigs. Ascorbic acid deficiency did not seem to disturb the utilization of fructose and galactose by guinea pigs. The glycogen contents of the liver and muscle of scorbutic guinea pigs were reduced markedly and did not differ significantly following ingestion of glucose, fructose or galactose. The disturbed carbohydrate metabolism in scurvy is attributed partly to diminished formation of glucose-6-phosphate from glucose.
Effectiveness of Levarterenol During Hemorrhagic Hypotension
Authors: Gilmore J. P.
Published: December 2017

When levarterenol was administered immediately following hemorrhage, the infusion continued for 1 hour, then stopped and the blood returned, the survival time of these animals was significantly longer than that of control animals which received a placebo infusion. During the hemorrhagic period 73% (11/15) of the untreated and only 20% (3/15) of the treated animals died. The results of the experiments indicate that levarterenol is an effective stopgap treatment for hemorrhagic hypotension pending whole blood transfusion.
Effect of Potassium on Ion Transport and Bioelectric Potentials of Frog Gastric Mucosa
Authors: Harris J. B. , Frank Heddy , Edelman I. S.
Published: December 2017

Ion transport of the isolated frog gastric mucosa was studied in vitro by the chamber method. The effects of modifications in the concentrations of potassium in nutrient (Kn+) and in secretory (Ks+) solutions on net potassium flux from nutrient to secretory phases (JnsKK+) on the rate of H+ production and on the transmucosal potential difference (PD) was studied in this system. Both the rate of H+ secretion and JnsKK+ increased when Kn+ was raised and decreased when Kn+ was lowered. Reduction of Kn+ to zero produced a striking depression of H+ secretion, which was reversed by adding K+ to the nutrient phase. Serial differences in H+ production (ΔH+) were approximately proportionate to the serial changes in Kn+. Transmucosal PD varied inversely with Kn+. Modification in Ks+ failed to alter H+ production or PD, although JKnsKns+ was decreased by raising Ks+.
Histamine Metabolizing Activity of Dog Stomach and Intestine
Authors: Kobayashi Yutaka , Ivy A. C.
Published: December 2017

The gastric mucosa of the dog was studied for histamine-metabolizing activity using only a microgram of C14-histamine. The intestinal mucosa which contains much diamine oxidase (histaminase) was used as a control tissue. No evidence of diamine oxidase was found in the cell-free extracts of the gastric mucosa though much diamine-oxidase activity was present in the cell-free extracts of the intestinal mucosa. A small amount of histamine destruction not inhibited by aminoguanidine and semicarbazide occurred in minced tissue digests of both the fundic and pyloric mucosa.