bluuebunny/crossref_metadata_2025 huggingface dataset:
Potassium and Sodium Exchange in the Working Frog Heart Effects of Overwork, External Concentrations of Potassium and Ouabain
Authors: Schreiber Sidney S.
Published: December 2017

Potassium and sodium exchange was studied in vitro in the working frog heart with the use of the radioactive isotopes K42 and Na24. Measurement of loss or gain of radioactivity, and hence the outflux or influx of the cations, is accomplished by placing a test tube containing the continuously perfused preparation into the well of a scintillation counter. Intracellular potassium in the working ventricle exists in two phases or components which exchange at different rates. The slowly exchanging phase is sensitive to the amount of work performed, external concentrations of K and failure of the contractile mechanism. The digitalis glycoside, ouabain, causes an inhibition of entrance of potassium into the slowly exchanging phase, while the fast component exchanges freely. It is suggested that the two phases of potassium exchange exist in parallel within the cell, and that potassium exchanges freely across a nonlimiting membrane.
Effects of Heart Rate on Coronary Flow and Cardiac Oxygen Consumption
Authors: Laurent D. , Bolene-Williams C. , Williams F. L. , Katz L. N.
Published: December 2017

The effects of electrically-induced heart rate (up to 300 beats/min.) on coronary flow and cardiac oxygen consumption has been studied in an open-chested intact preparation. A significant correlation between heart rate, coronary flow and cardiac oxygen consumption has been found at each level of cardiac work. Coronary flow and cardiac oxygen consumption increase with a rise in heart rate and seem to approach a limit at extremely rapid heart rates. Nomograms relating heart rate, work and oxygen consumption of the heart have been constructed. From these it is seen that heart rate is an important factor in determining the myocardial oxygen consumption; this is true at each level of cardiac work. The significance of these findings have been discussed relative to the unanesthetized animal. Under conditions of excessive heart rate or cardiac load which presumably lead to unusually high energy requirements, a radical departure from the expected ‘normal’ values was found in coronary flow, coronary A-V oxygen difference and cardiac oxygen consumption. This confirms the presence of ‘spontaneous’ change previously described by us. Its meaning and significance is discussed. Under these conditions of ‘spontaneous’ change coronary flow was increased, oxygen consumption decreased and coronary venous oxygen was raised as the coronary A-V oxygen difference declined. This ‘spontaneous’ change shifted the relationship of coronary flow to oxygen consumption. Furthermore, it led to a rise in coronary flow despite an elevation in coronary venous oxygen. It would seem that at this time the energy metabolism of the heart must change in that less oxygen is extracted from the blood despite an increase in its availability. The heart may therefore operate anaerobically in part or may make use of other hydrogen acceptors in the blood. The fact that this kind of metabolism may last as long as an hour or more, excludes the ordinary type of ‘oxygen debt.’
Hematocrit Ratio of Blood Within Mammalian Kidney and Its Significance for Renal Hemodynamics
Authors: Pappenheimer J. R. , Kinter W. B.
Published: December 2017

Evidence is presented indicating that the dynamic hematocrit of intra-renal blood is normally about one-half that in blood entering or leaving the kidney. The hematocrit ratio of intrarenal blood, relative to that in arterial blood, varies with the corpuscular concentration in arterial blood and inversely with the renal arterial blood pressure. When the blood pressure is reduced from 140 to 50 mm Hg, the vascular volume of the kidney decreases from 24% to 19% of the kidney volume and the kidney weight decreases by a like amount (i.e. 5%). Owing to the increased intrarenal hematocrit, however, the absolute quantity of red cells in kidneys removed at low pressure is usually greater than in their contralateral controls removed at high pressure. A theory is advanced to take account of the low dynamic hematocrit ratio in intrarenal blood and its variations with arterial pressure and corpuscular concentration. The theory supposes that red cells are progressively separated from plasma by a process of plasma skimming in the interlobular arteries. The deeper glomeruli are supplied primarily with plasma, leaving a highly viscous, cell-rich component of the blood to supply the terminal arterioles. After traversing the efferent arterioles, the cell-rich moiety of the blood is presumed to pass through a short circulation (preferential channels for red cells) bypassing the peritubular capillary network. The energy for the separation process is presumed to be supplied by the kinetic energy of renal arterial blood; the separation process is therefore dependent upon velocity and cell concentration. Applications of the theory to the following topics in renal physiology are discussed: a) the dynamic hematocrit of intrarenal blood; b) autoregulation of the renal circulation as a function of arterial pressure and corpuscular composition; c) afferent and efferent arteriolar resistance and the mechanism of regulation of glomerular filtration rate; d) renal extraction of PAH and Diodrast; e) oxygen supply of the kidney and its variation with blood flow.
Anterior Pituitary Growth Hormone and Blood Sugar Levels of Normal and Diabetic Dogs
Authors: Sirek Otakar V. , Best Charles H.
Published: December 2017

In a study of blood sugar levels in 17 normal and 11 totally depancreatized dogs many experiments have been performed in an attempt to determine the mechanisms which cause the differences in response to a single injection of highly purified growth hormone preparations. The sugar level of the depancreatized but not of the normal dog is very sensitive to a single injection of growth hormone. When the hormone preparation is administered to a diabetic dog with a relatively low blood sugar level, i.e. well below 200 mg % an immediate rise is produced. At a preinjection level well above 200 mg % a temporary fall of the blood sugar occurs. The rise in blood sugar was prevented by blocking the adrenergic system with dihydroergotamine. It has therefore been concluded that growth hormone stimulates the adrenergic system and that the initial rise in blood sugar is probably the result of breakdown of glycogen in the liver. The initial fall in blood sugar due to growth hormone can be obtained in fasting depancreatized animals kept without insulin for 24 hours. The fall is less pronounced in animals kept without insulin for from 72–96 hours and is completely abolished when the dogs have been twice ‘pretreated’ with large doses of growth hormone. These results indicate as definitely as this indirect method of approach can that the blood sugar lowering effect of growth hormone preparations is intimately associated with the presence of insulin in the body.
Effects of Carbon Dioxide Inhalation on Potassium Liberation From the Liver
Authors: Fenn Wallace O. , Asano Tomoaki
Published: December 2017

Changes in the concentration in the blood plasma of potassium, phosphate, chloride, sodium bicarbonate and glucose were followed in anesthetized cats during the inhalation of different concentrations of CO2 in oxygen for periods of 30 minutes or more. The typical response consisted of a rapid elevation of K with a return to normal and a slow progressive increase in both glucose and phosphate. The adrenal-sympathico-hepatic system is involved since the response is largely abolished by cervical section of the spinal cord, by adequate doses of adrenergic blocking agents and by simultaneous clamping of the hepatic artery and portal vein, and is usually diminished by adrenalectomy. Estimates were made of the total absolute amounts of K, glucose and P so liberated and the molecular ratios were found to be approximately 4:13:1. This is relatively more K than is usually associated with glycogen storage in the liver. Further analyses in the blood indicated an increase in the density of both blood and plasma due to loss of water. At the same time there is a decrease in the concentration of both Na and Cl in the plasma as well as a decrease in bicarbonate as measured after equilibration with 5% CO2. This acidosis, due partly to lactic acid, occurs in spite of the fact that the gain in K and loss in Cl exceeds the loss in Na. The response of the liver to high CO2 has a threshold which is usually between 10 and 20%. At concentrations of CO2 below this threshold there is a small fall in plasma K which would be expected from the fact that whole blood is better buffered than tissues.
Natural Frequency, Damping Factor and Inertance of the Chest-Lung System in Cats
Authors: Brody Alfred W. , DuBois Arthur B. , Nisell Ove I. , Engelberg Joseph
Published: December 2017

A study of the local surface velocity of the chest and abdomen as a function of the frequency of sinusoidal pressure waves introduced into the airways via the trachea, was made in 15 cats. The study confirmed and extended the observations DuBois, Brody, Lewis and Burgess had previously made in human beings and demonstrated that the effects seen were not produced by any part of the airway above the trachea. Comparison is made of this data with the averaged data obtained by using a plethysmograph to integrate the surface responses of the cat. The natural frequency (9.6, S.E. = 0.6 cps), damping factor (2.0, S.E. = 0.25), resistance ( k1 = 13.5, S.E. = 2.3 cm H2O/(l/sec.); k2 = 76, S.E. = 21 cm H2O/(l/sec.)2, and elastance (230, S.E. = 26 cm H2O/l.) were measured and the inertance (.09, S.E. = .008 cm H2O/(l/sec.2)) was calculated. The implications of these concepts and measurements for respiratory mechanics and ballistocardiography are discussed.
Electrolytes and Acid-Base Balance in Hypothermia
Authors: Axelrod D. Robert , Bass David E.
Published: December 2017

Dogs were cooled in an ice-water bath, and plasma electrolytes were measured at heart temperatures of 38°C, 28°C and 25°C. A ‘cold acidosis’ occurred during hypothermia that is attributable largely to temperature-influenced physico-chemical factors related to the buffer systems. A slight respiratory depression is of greater importance in decreasing plasma ph at lower body temperature than at normal body temperature.
Effect of Environmental Temperature on Reaction of Mice to Parathion, an Anticholinesterase Agent
Authors: Baetjer Anna M. , Smith Raymond
Published: December 2017

Mice were exposed to three environmental temperatures, 60°, 73° and 96°F, for 3 days before and after intraperitoneal injection with an anticholinesterase, parathion. The onset of deaths, rate of dying and rate of recovery were more rapid, the survival time of the fatal cases was shorter, and the mortality was higher at 96° than at 73°F. At 60°F, the onset of deaths was delayed, and the final but not the early mortality exceeded that at 73°F. Somewhat similar, though less significant, differences occurred with intravenous injections. Experiments with different pre- and postinjection temperatures showed that mortality varied directly with pre- and inversely with postinjection temperatures and latent period varied inversely with preinjection temperatures. For comparison, acetylcholine and neostigmine were injected intraperitoneally in mice at these three temperatures. The rate of dying and mortality were only slightly greater at 96° than at 73°F. At 60°F the onset of deaths was delayed, the animals died more slowly and the mortality was significantly lower than at 73°F. The results cannot be attributed to acceleration of chemical reactions with changes in body temperature but appear to be due to variations in rate of absorption and other factors.
Collateral Circulation to the Brain of the Dog Following Bilateral Ligation of the Carotid and Vertebral Arteries
Authors: Whisnant Jack P. , Millikan Clark H. , Wakim Khalil G. , Sayre George P.
Published: December 2017

Ligation of various combinations of arteries in the neck in 21 dogs demonstrated that there is little clinical effect following ligation of three or less of the major arteries to the brain and that most dogs survive after all the major arteries to the brain are ligated in the neck. A procedure is described in which the collateral circulation is determined by injection of liquid vinyl acetate into the arterial tree in dogs immediately after death subsequent to one-stage ligation of all the major arteries to the brain. The main anastomotic channels are branches of the costocervical and omocervical arteries that join muscular branches of the vertebral arteries beyond the ligated points. No anastomotic channels were detected in the carotid systems.
Rate of Metabolism of Ethanol in the Rat
Authors: Aull J. C. , Roberts W. J. , Kinard F. W.
Published: December 2017

Rats, fasted 18 hours, were injected intraperitoneally with 2.85 or 3.0 gm/ kg of ethanol. Blood samples were obtained 1.5 and 4.5 hours later. The entire rat was ground and mixed. The ethanol concentration of blood and tissues was determined. The rate of metabolism was lower and the factor r higher when calculated from the declining blood values than when determined directly. The factor r did not bear a close relation to total body water or ether-extract. The rate of alcohol metabolism varied from animal to animal within the species despite efforts to maintain constant experimental conditions.
Seminal Vesicle Growth as a Function of Androgen Stimulation in Mice
Authors: Chai C. K.
Published: December 2017

One hundred fourteen mice castrated at weaning were given different dosages of testosterone propionate by daily subcutaneous injection for 20 days. The seminal vesicle weight was chosen as the quantitative indicator of growth response in secondary sex organ. Thirty-four noncastrates were used for comparison. The growth of the seminal vesicles in response to the different dosages of hormone stimulation was shown, as are population growths, to be well fitted with the logistic curve. It was found also that the point of inflection of the dose-response curve was at a seminal vesicle weight which was close to the seminal vesicle weight of the untreated controls.
Measurement of Size and Turnover Rate of Body Glucose Pool by the Isotope Dilution Method
Authors: Steele R. , Wall J. S. , de Bodo R. C. , Altszuler N.
Published: December 2017

Glucose uniformly labeled with C14 was administered intravenously in minute amounts to unanesthetized dogs in the postabsorptive state as an initial dose followed by a continuous infusion. The C14 content of the plasma glucose was determined at intervals. When the ratio of priming dose to infusion rate was suitable, the plasma glucose specific activity remained relatively constant during the 60–180-minute period of the infusion, whereas during the first 60 minutes it decreased in a manner indicating the presence of two compartments exchanging glucose with the plasma glucose compartment. For a typical experiment of this kind, the amounts of glucose in these compartments and the rates at which these bodies of glucose underwent mixing with the plasma glucose were calculated. It was then possible to determine the magnitude of the errors in body glucose pool size and inflow-outflow (i.e., turnover) rate which are made when measurements are carried out at various ratios of priming dose to infusion rate. These errors are incurred when the usual simplifying assumption is made that instantaneous mixing occurs throughout the body glucose pool. It was found that there is an extensive range of ratios of initial dose to infusion rate over which the errors are small enough (less than ± 5%) to be ignored; it is not necessary to carry out a preliminary experiment on each dog to establish a desirable ratio. Average values of body glucose pool size and glucose inflow-outflow rate obtained in 10 experiments with seven normal dogs are compared with values which have been reported by others. The physiological significance of these parameters measured by isotope dilution is discussed.
Effects of Repetitive Peripheral Stimuli on Evoked Potentials of Somatosensory Cortex
Authors: Rosner Burton S.
Published: December 2017

Evoked potentials were recorded with a macroelectrode at somatic area I of cerebral cortex of cats under pentobarbital sodium anesthesia. Repetition rate (interstimulus interval) of trains of brief electrical pulses to the skin varied from 0.30–3.00 seconds. Average amplitude of response did not reach a maximal, stable level until repetition rates of 2.00 seconds and longer were used. When repetition rate was fixed and responses were studied as a function of the serial number of a stimulus in a train, amplitude slowly declined to a stable level as more stimuli were given. Besides these monotonic effects, a cyclic component appeared in both the repetition rate and serial number functions. All results are explained by assuming that the recovery function set off by one stimulus in a train starts later, or is slower than, the recovery function produced by the preceding stimulus; this progressive slowing of recovery ceases when equilibration is reached. Temporal interaction between successive stimuli at somatosensory cortex clearly lasts for several seconds, as other workers find at visual cortex.
Fluid Movement Across the Wall of the Small Intestine in Vitro
Authors: Wilson T. Hastings
Published: December 2017

Small sacs of everted jejunum of the hamster were incubated in sugar free bicarbonate-saline solution in vitro. Both fluid and sodium chloride moved across the wall of the intestine from mucosal to serosal side. This movement of isotonic saline solution across the intestine was inhibited anaerobically. A small bicarbonate secretion was noted in the direction of serosal to mucosal side.
Endogenous Histamine Excretion in the Rat as Influenced by X-Ray Irradiation and Compound 48/80
Authors: Leitch James L. , Debley Virginia G. , Haley Thomas J.
Published: December 2017

Studies have been made on a spasmogen from rat urine. This material has been identified as histamine. It has been shown that both acute whole body x-ray irradiation and compound 48/80 significantly increase the quantity of endogenous urinary histamine. Endogenous histamine excretion in female rats is approximately 9–10 times greater than in male rats. Neither x-ray irradiation nor compound 48/80 elevate the amount of urinary histamine of the males to that of the female. Histamine liberation is of little or no importance insofar as lethality from acute whole body irradiation is concerned. The amount of histamine liberated by such irradiation is independent of radiation dosage within the range 600–1200 r. After radiation injury, significant levels of urinary histamine were detected only during the first 24 hours. Histamine depletion by chronic administration of compound 48/80 did not prevent further liberation of histamine by acute whole body irradiation. Irradiated animals are much more susceptible to the toxic effects of compound 48/80 than normal animals. Gonadectomy followed by α-estradiol injection did not increase the output of urinary histamine in male rats. Similar treatment of female rats with testosterone did not reduce their urinary histamine output, but a reduction was observed 140 days after surgery. Administration of cortisone acetate to male rats did not increase their excretion of endogenous histamine. Inactivation of diamine oxidase with aminoguanidine had little or no effect on urinary histamine output in male rats, but caused a threefold increase in females. Further elevation in urinary histamine was produced by irradiation or compound 48/80.
Effects of Irradiated and Reconstituted Uridine on Growth of a Neurospora Crassa Mutant and Synergism Between Uridine and Uracil
Authors: Canzanelli Attilio , Sossen Rhea , Rapport David
Published: December 2017

Solutions of uridine were irradiated with ultraviolet light for varying periods, resulting in a progressive loss of the selective ultraviolet absorption spectrum. Such absorption can be restored (‘reconstitution’) by treatment of the irradiated material with heat, acid, a combination of the two, and alkali, though the restored spectrum is not identical with spectrum of uridine. Further study of the ‘reconstituted’ material shows that both uridine and uracil were present in varying percentages, depending on the duration of irradiation, as was a small amount of ribose, and small amounts of two other unidentified U.V.-absorbing substances. The growth of a uridine-requiring mutant of Neurospora crassa is well supported by the ‘reconstituted’ material. Uracil will also support growth of the mutant, but only in much larger concentrations than is the case with uridine and after a latent period of several days. Uracil, in concentrations which alone are not adequate for immediate growth, will support growth if ‘catalytic’ amounts of uridine are added either simultaneously or previously. The possible mechanisms of this synergism are discussed.
Changes in Blood Glucose During Metabolism of ß Hydroxybutyrate
Authors: Neptune Edgar M.
Published: December 2017

Following the rapid intravenous infusion of sodium d,l ß hydroxybutyrate there is a consistent drop in blood glucose. This did not occur in animals receiving an equivalent amount of sodium as sodium bicarbonate. Following both the ketone and sodium bicarbonate infusion there is a rise in serum orthophosphate; these latter changes are considered to be caused by alkalosis. The fall in blood sugar suggests a possible participation of glucose in ketone metabolism.
Autonomic Control of Blood Flow in Hind Paw of the Dog
Authors: Green Harold D. , Howard William B. , Kenan Leroy F.
Published: December 2017

Blood flow was measured in the hind paw of the dog by directing blood from the femoral artery through an electromagnetic flowmeter and into the dorsalis pedis artery. The system was such that minimal flow was measured in skeletal muscle in the foot. Under the conditions of these experiments, epinephrine and arterenol, injected intra-arterially, exerted potent vasoconstrictor effects, the former being slightly but not significantly more potent than the latter when equimolecular doses were used. Isoproterenol and methacholine caused weak dilator responses. Ischemia did not induce any reactive vasodilation. Stimulation of the sympathetic chain at approximately the level of the first sacral vertebra induced potent vasoconstriction. All constrictor effects were blocked by 10 mg of phenoxybenzamine (Dibenzyline) given intra-arterially without affecting appreciably the dilator responses to either the methacholine or the isoproterenol. It is concluded that this vascular bed contains potent innervated alpha constrictor receptors but but that adrenergic and cholinergic dilator receptors are minimally present. No evidence was obtained for the presence of cholinergic autonomic dilator fibers.
Transmission in Ganglion-Free Circular Muscle From the Cat Intestine
Authors: Prosser C. Ladd , Sperelakis Nick
Published: December 2017

Rings and strips of circular muscle from cat intestine show bursts of fast potentials (each 0.05–0.1 sec. duration) in spontaneous or barium-induced activity or in response to shocks. Conduction in the long direction of the fibers is at 4 cm/sec.; there is some lateral conduction at about 3 cm/sec. which decrements, leaving an active band about 3 mm wide to spiral around a ring of muscle. If a ring is partly slit, forming two rings connected by a bridge, a wave of activity may cross from one side to the other; crossing depends on local excitability which may be enhanced by citrate or barium or may be depressed by high potassium, and conduction may go in one or both directions. If the slit is complete, similar crossing occurs if the two rings are in close contact for as little as one-fifth of their circumference. Crossing at a zone of contact is not stopped by saline shunt and resembles normal spiral conduction. Short-fibered muscle has higher resistance and shows a greater reactive component than long-fibered muscle although in intestinal muscle the cell membranes must impose relatively little resistance. Electron microscopy reveals no sarcoplasmic continuity from fiber to fiber. An ephaptic hypothesis of interfiber conduction is suggested.
Body Temperature of the Camel and Its Relation to Water Economy
Authors: Schmidt-Nielsen Knut , Schmidt-Nielsen Bodil , Jarnum S. A. , Houpt T. R.
Published: December 2017

The rectal temperature of normal healthy camels at rest may vary from about 34°C to more than 40°C. Diurnal variations in the winter are usually in the order of 2°C. In summer the diurnal variations in the camel deprived of drinking water may exceed 6°C, but in animals with free access to water the variations are similar to those found in the winter. The variations in temperature are of great significance in water conservation in two ways. a) The increase in body temperature means that heat is stored in the body instead of being dissipated by evaporation of water. At night the excess heat can be given off without expenditure of water. b) The high body temperature means that heat gain from the hot environment is reduced because the temperature gradient is reduced. The effect of the increased body temperature on heat gain from the environment has been calculated from data on water expenditure. These calculations show that under the given conditions the variations in body temperature effect a considerable economy of water expenditure. The evaporative heat regulation in the camel seems to rest exclusively on evaporation from the skin surface (sweating), and there is no apparent increase in respiratory rate or panting connected with heat regulation. The evaporation from isolated skin areas increases linearly with increased heat load. The critical temperature at which the increase sets in is around 35°C. The fur of the camel is an efficient barrier against heat gain from the environment. Water expenditure is increased in camels that have been shorn.
Renal Function During Hypothermia and Hibernation
Authors: Hong Suk Ki
Published: December 2017

The alterations of urine flow and composition during hypothermia were studied in unanesthetized rats and ground squirrels. One ureter or the urethra was cannulated in some animals for continuous urine collection. Within 5–10 minutes of the onset of cooling, the urine flow diminished to an almost immeasurable level and then recovered to a level lower than the precooling one. This diminution may be due to the stimulation of the sympathetic nervous system. As the body temperature was further lowered, urine flow progressively decreased. Both water and solute diuresis, if already under way before the onset of hypothermia, were also reduced during hypothermia without increase in solute concentration. However, any infusion of fluid during hypothermia augmented the urine flow. This augmented urine flow was not inhibited by injected Pituitrin. During hypothermia the renal blood flow was quantitatively greatly reduced, while the changes in the hematocrit ratio or in the refractive index of plasma were not consistent. These facts suggest that decrease in glomerular filtration rate, which follows the reduction in renal blood flow, may be the main cause for this great reduction in urine flow during hypothermia. The solute concentration of the urine formed during hypothermia was more independent of the urine flow, so that the normal volume-concentration relationship is upset, suggesting that water and solute reabsorptions are dissociated. When 0.50 m NaCl solution was infused during hypothermia, a large amount of dilute urine was excreted, probably due to the inability of tubules to reabsorb the water and chloride loads presented. The hypothermic animals also failed to concentrate urea in the urine. Reducing substances were excreted. The excretion of phenolsulfonephthalein (PSP), in terms either of the percentage return in the urine after intravenous administration or of the blood plasma clearance, was also lowered during hypothermia. Urine/plasma concentration ratio of chloride or PSP was lower during hypothermia. These suggest that tubular functions, both reabsorptive and secretory, are depressed during hypothermia. During hibernation the urine flow was similarly slow and the urine was dilute.
Effect of Dietary Pectin, ‘Protopectin’ and Gum Arabic on Cholesterol Excretion in Rats
Authors: Lin T. M. , Kim K. S. , Karvinen Esko , Ivy A. C.
Published: December 2017

The addition of pectin and a protopectin preparation containing galactose and arabinose to a noncholesterol-containing basal diet increased the fecal excretion of saponifiable lipids; the absorption of endogenous cholesterol and the excretion of nonsaponifiable lipids were uninfluenced. The addition of pectin to a basal diet containing cholesterol increased the excretion of fecal saponifiable and nonsaponifiable lipids and decreased the absorption of exogenous cholesterol. The addition of the protopectin preparation to the same diet had no significant effect on the excretion of saponifiable lipids, but the excretion of cholesterol was decidely reduced and, in two experiments out of three, there occurred an approximately equivalent increase in noncholesterol nonsaponifiable material. The addition of gum arabic or arabinose to this ration produced practically no changes in the amount of saponifiable and nonsaponifiable fecal lipids and in the recovery of exogenous cholesterol in the feces. Only very small quantities of noncolor-developing sterols were eliminated either on the cholesterol basal diet or when this diet was supplemented with pectin, protopectin, gum arabic or arabinose.
Effect of Hypoglycemia on Auditory Cortex and Cochlear Receptor in the Cat
Authors: Fernández César , Brenman Arnold
Published: December 2017

Effect of hypoglycemia induced by insulin and/or functional evisceration on auditory cortex and cochlear responses to sound stimuli was studied in cats. Both responses remained unchanged at blood sugar levels as low as 5 mg %. They diminished in size whenever blood pressure was allowed to fall to low values, and returned to nearly normal when it was restored. The observations suggest that carbohydrates are not essential for cochlear function or that the structure contains a large store of them. The presence of responses from auditory cortex during medullary stage of coma suggests that this area does not conform well to the concept of phyletic organization of the central nervous system.
Utilization of Exogenous Fat and Turnover Rate of Endogenous Fat in the Normal and Hypophysectomized Rat
Authors: Matthews LeRoy W. , Spector Samuel , Lemm Joy , Olynyk Paul
Published: December 2017

The utilization of C14-labeled trilaurin and tripalmitin administered by both oral and intravenous routes and the turnover rate of total body fat was studied in normal and hypophysectomized rats. The hypophysectomized rats were found to utilize significantly more fat per millimole of CO2 expired than normal rats. This increased utilization of exogenous fat varied from 14 to 97% for the various fats and routes of administration and was found in both fasting and fed rats. The turnover rate of endogenous total body fat was found to be almost twice as rapid in the hypophysectomized rats with the half-life of total body fat 9.0 ± 1.33 days as compared to 14.9 ± 0.15 days in the normal rats. The fat content of the hypophysectomized rats was 11.12 gm/100 gm body weight compared to 8.29 gm/100 gm body weight in the control rats. When both of these factors are taken into consideration, the hypophysectomized rats are found to utilize 0.86 ± 0.13 gm of endogenous fat/100 gm body weight/ day and the normal rats only 0.38 ± 0.04 gm of endogenous fat/100 gm body weight/day. In the presence of this marked increase in total fat metabolism in the hypophysectomized rats, there is only a slight hyperlipemia, which may be accounted for by an increased serum cholesterol, a decreased fat content of the liver and an increased total body fat.
Temperature Changes in the Blood of the Pulmonary Artery and Left Atrium of Dogs During Exposure to Extreme Cold
Authors: Good A. L. , Sellers A. F.
Published: December 2017

Polyethylene cannulae were surgically placed in the pulmonary artery and left atrium of dogs; thermistors mounted in polyethylene tubing and hypodermic needles, were passed through these cannulae and the temperature changes of the blood and rectum were recorded photographically. Continuous recordings of these temperature changes in unanesthetized dogs were made when the experimental animals were suddenly exposed to an ambient temperature of –35°C for 30 minutes. Shivering began immediately after exposure to cold; blood and rectal temperatures increased 0.4–0.5°C during the 30 minutes of exposure. It was found that the rectal temperature exceeded the left atrial blood temperatures from 0.2 to 0.3°C, and that in all experiments except one, the left atrial blood temperature exceeded that of the pulmonary artery from 0.01 to 0.15°C. Increased metabolism, along with cutaneous vasoconstriction probably explains the rise in blood and rectal temperatures during exposure to cold. Thermodynamic considerations of carbon dioxide and oxygen exchanges in the lungs lend support to the findings regarding the pulmonary artery-left atrial blood temperature gradient.
Utilization of Fructose, Galactose and Glucose by Diabetic Rabbits
Authors: Banerjee Sachchidananda , Divakaran Eswaramangalath Ramankutty
Published: December 2017

Fructose, galactose and glucose were fed to normal and alloxan-diabetic rabbits. Some of the animals received an intravenous injection of dihydroergotamine prior to the feeding of fructose. The levels of these sugars and true glucose were estimated in samples of blood collected for varying periods after the administration of these sugars. These sugars were also determined in the urine of the animals. Fructose and galactose were removed from the blood very rapidly in both the normal and diabetic rabbits and insignificant amounts of these sugars appeared in the urine. There was a considerable increase in the true blood glucose level and increased amount of glucose appeared in the urine of diabetic rabbits after fructose or galactose was fed. Dihydroergotamine partly suppressed this hyperglycemia after the administration of fructose. Alloxan-diabetic rabbits in spite of their normal ability to initiate the metabolism of fructose and galactose, either transform a considerable amount of these sugars into glucose or spare the utilization of blood glucose. Superiority of these sugars as alternate source of energy is questioned.
Effect of Bone Marrow Therapy on the Volitional Activity of Whole-Body X-Irradiated Rats
Authors: Jones D. C. , Kimeldorf D. J. , Castanera T. J. , Rubadeau D. O. , Osborn G. K.
Published: December 2017

Postirradiation injection of bone marrow suspension was used to test the hypothesis that the decrease in volitional activity seen during the 2nd and 3rd weeks after whole-body x-irradiation in the lethal range is related to damage of the hematopoietic system. The marrow preparation used was found to afford statistically significant protection in terms of lethality. Surviving irradiated animals treated with bone marrow suspension showed no decrease in activity during the 2nd and 3rd weeks postirradiation, even though the radiation dose used (650 r) was in excess of that required to produce such a decrease in the volitional activity of nontreated irradiated animals. Since the bone marrow treatment apparently affects hematopoiesis specifically, it appears that the volitional activity decrement during the 2nd and 3rd weeks after whole-body irradiation is related to hematopoietic damage. Further, it appears that a greater functional hematopoietic capacity is necessary to maintain normal volitional activity levels than is required to survive after x-irradiation.
Metabolism of C19 Steroids by Homogenates of Kidney, Heart, Testes and Prostate
Authors: Kochakian Charles D. , Carroll Betty R. , Uhri Barbara
Published: December 2017

The metabolism of ten C19 hydroxysteroids by kidney, heart, testes and prostate homogenates of male guinea pigs has been compared. The metabolites formed were isolated and characterized. A very wide variation not only in the metabolism of the steroids by the same tissues but also the different tissues was noted. Kidney contained the greatest activity, prostate showed practically no ability to oxidize any of the steroids and epitestosterone was not metabolized by any of the tissues.
Pulmonary and Systemic Vascular Response to Continuous Infusion of 5-Hydroxytryptamine (Serotonin) in the Dog
Authors: Rudolph Abraham M. , Paul Milton H.
Published: December 2017

The pulmonary and systemic vascular responses to continuous venous infusion of 5-hydroxytryptamine were studied in eight dogs. Chronic catheterization of the pulmonary artery, aorta, and in some animals, the left auricle, permitted repeated studies in the same animal. Infusion rates as low as 20 µg/kg/min. of serotonin creatinine sulfate resulted in a twofold increase of pulmonary arterial pressure. In 11 experiments with an infusion rate of 150 µg/kg/min. there was a 300% increase of mean pulmonary pressure, a 28% drop in systemic arterial mean pressure, and a 60% rise of cardiac output. Calculated pulmonary resistances markedly increased to 500% of control levels, but in contrast, systemic resistances decreased by 55%. 5-Hydroxytryptamine is a powerful vasoconstrictor of the pulmonary vessels and a vasodilator of peripheral vessels, when administered by continuous infusion, and these effects persist as long as the drug is administered. The possible role of 5-hydroxytryptamine in production of pulmonary hypertension in congenital heart disease is considered.
Glucose-6-Phosphate in Estronase Enzyme Systems
Authors: Bischoff Fritz , Torres Adolfo , Lopez Guillermo
Published: December 2017

The estronase activity (conversion of estrone to estradiol) of rabbit red cells is more than tripled by the substitution of glucose-6-phosphate for glucose. This augmentation with glucose-6-phosphate occurs with human red cells to a somewhat lesser degree and was not observed for 11 diverse mammalian tissues studied, including those with high estronase activity like rat lung, human glandular mucosa and human epidermoid carcinoma of the lung, and those with low estronase activity like human lymph nodes and human muscle. The addition of TPN to rabbit red cells accelerated the action of glucose but not glucose-6-phosphate with and without glucose-6-phosphate dehydrogenase.
Effects of Oxygen at High Pressure on the Transport of Potassium, Sodium and Glutamate in Guinea Pig Brain Cortex
Authors: Kaplan S. A. , Stein S. N.
Published: December 2017

Slices of guinea pig brain cortex were suspended in a medium containing inorganic ions (in concentrations similar to those present in plasma), glucose and glutamate. They were shaken for 90 minutes at 37°C in oxygen, the partial pressure of which was varied from 1 to 11 atm. absolute. Raising the pressure above 4 atm. absolute resulted in the slices losing considerable quantities of potassium. At 6 atm. absolute the slices accumulated considerably less glutamic acid than they did at 1 atm. These findings suggest that brain cells are unable to maintain their normal concentrations of these two substances when exposed to oxygen at high pressure and suggest a possible mechanism for the origin of the disturbances of function in the central nervous system of animals exposed to high pressures of oxygen.
Sodium, Potassium and Glutamate Content of Guinea Pig Brain Following Exposure to Oxygen at High Pressure
Authors: Kaplan S. A. , Stein S. N.
Published: December 2017

Intact animals exposed to 6.6 atm. absolute of oxygen showed a significant increase in brain sodium although the potassium content remained unchanged. There was also no change in glutamate content after exposure to OHP. The experiments seem to provide additional evidence that changes in brain electrolyte content or ‘binding’ are significant in the chain of events leading to increased brain excitability after exposure to OHP.
Microscopic Studies of Skin Blood Vessels in Relation to Sympathetic Nerve Stimulation
Authors: Lee J. S. , Visscher M. B.
Published: December 2017

Studies have been made of the diameters of microscopic and macroscopic blood vessels in the leg skin of 8 dogs and 13 cats, under pentobarbital anesthesia in parallel with observations on blood pressures in similar vessels, using two techniques, micro-cannulation and a recently described micro-chamber method. During stimulation of the homolateral sympathetic trunk, with or without curarization, there was a rise in venule and small vein pressure, associated with an initial decrease in venous vessel diameter. After cessation of stimulation the venous diameters returned to or exceeded control values while the arteriolar diameters were still markedly reduced. These observations provide direct evidence that even in the absence of mechanical obstruction to venous blood flow the pressures in venules, and therefore necessarily in capillaries when blood is flowing forward, may be elevated by sympathetic nerve stimulation which reduces the blood flow into the vascular bed in question. The possible importance of this mechanism in edema formation and in blood pooling is pointed out.
Development of Tolerance to Ozone in Reference to Pulmonary Edema
Authors: Matzen Richard N.
Published: December 2017

Massive pulmonary edema, varying degrees of alveolar hemorrhage and tracheo-bronchial inflammation occur in animals exposed to high concentrations of ozone. Initial exposures to low concentrations of ozone can prevent the formation of edema and death on subsequent severe exposures in mice. This tolerance was shown to be detectable in 24 hours and present for as long as 102 days. Protection is rendered against a challenging dose as high as 2 1/2 times the ld50. The signs caused by exposure suggest that the central nervous system may be affected as well as the lungs.
Response of the Chronic Gastric Fistula Rat to Histamine
Authors: Lane Ardelle , Ivy A. C. , Ivy Emma K.
Published: December 2017

The preparation of chronic gastric fistula rats, their care and how they may be used for physiological and pharmacological studies on gastric secretion is described. The rat has a large interdigestive secretion and secretes free acid (pH 4.5) after 48–72 hours of fasting. For controlled studies this requires the replacement of fluid and chlorides. Statistically significant differences between the control output of acid and the response to 1 mg of histamine diphosphate were obtained. The threshold dose of the diphosphate is approximately 0.1 for a 350-gm rat. The least amount of histamine diphosphate to yield an average maximum output of acid (10 mg/hr.) is 0.5 mg subcutaneously every 15 minutes. The body dose of histamine required to stimulate gastric secretion is about the same in man, dog, cat and the rat. On the basis of body weight, the amount of histamine base required to yield a maximum output of acid in the rat is 34.6 µg/kg/min. as compared with 1.6 µg/kg/min. in the dog.
Influence of Some Environmental Factors on Plasma and Urinary 17-Hydroxycorticosteroid Levels in the Rhesus Monkey
Authors: Mason John W. , Harwood C. Theresa , Rosenthal Nathan R.
Published: December 2017

Observations in the rhesus monkey are described suggesting a close relationship between emotional responses to environmental factors and pituitary-adrenal cortical activity, as judged by plasma and urinary 17-OH-CS levels. Substantial elevations of plasma 17-OH-CS levels occurred in a group of normal monkeys following their first experience with a handling and venipuncture procedure. This effect did not occur in subsequent experiments of the same type. Animals placed in a chair restraining apparatus for the first time showed a moderate rise in urinary and plasma 17-OH-CS levels during the first few days but thereafter stabilized at low levels for at least 3 weeks. It is concluded that the chair technique is, therefore, suitable for studies of ACTH regulation and perhaps many types of biological studies. Urinary 17-OH-CS levels were approximately 30% lower on weekends than weekdays in monkeys kept in a laboratory room, presumably reflecting the influence of the animal's interaction with the everyday environment on the pituitary-adrenal cortical system.
Inhibition by Anticholinesterases of the Electrical and Mechanical Activity of Isolated Rabbit Auricles in Vitro
Authors: Marshall Jean M. , Katsh Seymour
Published: December 2017

Effects of Carcholin, Mecholyl, neostigmine and strychnine on spontaneously beating isolated rabbit auricles were studied by recording the transmembrane potential changes with intracellular microelectrodes and the contractions by means of a sensitive mechano-transducer. Electrical recordings were taken in both pacemaker and nonpacemaker areas. Carcholin (10–5 m) and Mecholyl (10–4 m) consistently shortened the duration of the action potential and diminished the developed tension. At higher concentrations Carcholin (10–3 m) and Mecholyl (10–2 m) arrested all auricular activity. Atropine (10–3 m) and epinephrine (10–3 m) restored activity. Following atropine or epinephrine, the inhibitory capacity of the anticholinesterases was abolished. Neostigmine and strychnine had variable effects.
Increased Survival in Irradiated Animals Treated With Bacterial Endotoxins
Authors: Smith Willie W. , Alderman Ilo M. , Gillespie Ruth E.
Published: December 2017

A single injection of endotoxin derived from Gram negative bacteria caused an increased survival in lethally irradiated animals when given immediately after or 24 hours before irradiation. Mice responded better to the injection before irradiation and hamsters to the injection after irradiation. The effect was associated with a reduction in infection, very pronounced in the case of α-streptococcus or Proteus and still significant in the case of Pseudomonas infection. No beneficial effect was obtained when mice were given three endotoxin injections during 1 week or six injections during 2 weeks prior to irradiation. The beneficial effect is not necessarily associated with the granulocytosis which begins within a few hours after the endotoxin injection, or with the conditions under which nonirradiated animals show an increased resistance to bacterial challenge.
Changes in Volume of Cortical Neuronal Elements During Asphyxiation
Authors: Van Harreveld A.
Published: December 2017

Cortical electrical resistance increases considerably after cortical asphyxiation. After a latent period of about 3 minutes a sudden resistance change occurs during which one-third of the cortical conductivity may be lost. It was postulated that this drop in conductance is due to a transport of ions, accompanied by water, from the extracellular spaces into the cortical cells and fibers. A swelling of cortical elements must thus be expected. The cortex was quickly frozen either before or after the sudden conductivity drop. The frozen cortex was kept in alcohol for 1 week during which the alcohol dissolves the ice in the cortex and fixes the tissue. Histological preparations stained with gallocyanin and with silver for the investigation of cells and fibers respectively were made. In rabbit cortex the mean diameter of nerve cells after the sudden conductivity drop was more than 11% greater than before the resistance change, which represents a volume increase of about 40%. The apical dendrites increased in diameter about 30% implying a volume increase of about 70%. If one assumes that the combined perikaryal and dendritic volume is 30% of the total cortical volume, then the amount of fluid stored by the cortical neurons during the sudden resistance change would amount to about 16% of the cortical volume. Such fluid and ionic movements are ample to explain the resistance changes observed.