bluuebunny/crossref_metadata_2025 huggingface dataset:
High altitude tolerance of normal dogs and dogs with myocardial infarcts
Authors: Maling Harriet M. , Highman Benjamin
Published: December 2017

Normal dogs, sham-operated dogs and dogs with large myocardial infarcts produced by coronary artery ligation were exposed to simulated altitudes of 34,000–38,000 feet for 3–3 1/2 hours. Twelve of thirteen normal dogs and all eight dogs with 3–14-day infarcts survived exposure to 34,000 feet. Five of six dogs with 2-day infarcts and three of six sham-operated dogs died during an exposure to 34,000 feet. There were no deaths among eight normal dogs and two deaths among four dogs with 7–18-day infarcts during exposure to 38,000 feet. Respiratory and heart rates increased markedly in all dogs at high altitudes. Throughout the exposures, ectopic ventricular beats were recorded frequently in most of the dogs with infarcts, less frequently in sham-operated dogs and rarely in normal dogs. Deaths among normal and sham-operated dogs and some of the deaths among dogs with infarcts were from respiratory failure. Two deaths from ventricular fibrillation were recorded in dogs with infarcts. Exposure to high altitudes did not modify significantly either the gross or histologic appearance of the infarcts.
Elastance and resistance of lungs-chest of dogs
Authors: Goodheart Clyde R. , Haddy Francis J. , Grodins Fred , Ebert Richard V.
Published: December 2017

Static elastance of the lungs-chest of seven curarized dogs averaged 15.2 ± 4.9 cm H2O/l. Elastance decreased with time probably because of stress relaxation. The expiratory volume flow rate for five different initial inflations was recorded as a function of time. Nondimensionalized plots were nonlinear, especially with the larger initial inflations, and shifted to the right as a function of initial inflation. A resistance which increases with flow rate because of a turbulent component is the most probable explanation for the complexity of a single free recovery curve. Either an increase in resistance, a decrease in elastance or both could account for the observation that the curves shift to the right with increasing initial volume.
Effects of acute elevation of blood CO2 tension on renal excretion of chloride and sodium by the anesthetized dog
Authors: Wesson Laurence G.
Published: December 2017

Ten per cent carbon dioxide was administered acutely to anesthetized 15–20-kg dogs which had been loaded with varying quantities of hypertonic NaCl, hypertonic NaHCO3 and, in some experiments, urea. In animals with low blood concentration and excretion rates of bicarbonate, CO2 had no effect on sodium chloride reabsorption as measured at constant creatinine clearance. In animals with normal or elevated blood concentration together with significant excretion rates of bicarbonate, CO2 resulted in a 5–7% increase in sodium chloride reabsorption. The effect on reabsorption was greater than predicted on the assumption that bicarbonate had depressed chloride reabsorption by acting as a simple osmotic diuretic and that CO2, by enhancing bicarbonate reabsorption, had removed some of this osmotic diuretic agent.
Renal handling of glucose in dogs
Authors: Chinard Francis P. , Taylor W. Rowland , Nolan Mary F. , Enns Theodore
Published: December 2017

Evidence has been obtained that glucose is transported across renal tubule cells with the 6-carbon chain intact and that glucose does not contribute significantly to renal carbon dioxide production. Injection is made rapidly into a renal artery of solutions containing T-1824 (assumed not to leave the circulation), creatinine and glucose appropriately labeled with C14. Relative to T-1824, creatinine recovery in renal vein blood averaged 74%; glucose recovery averaged 98%. Differences were apparent in the time-concentration curves of glucose and of creatinine; these disappeared after phlorizin and are considered to represent reabsorbed glucose. That little or none of the injected glucose was converted to nonvolatile carbon compounds was shown by paper chromatograms and radioautographs. That the carbon chain was not broken down and resynthesized was shown by the nonrandomization of C14 injected as glucose-1-C14 and as glucose-6-C14 in glucose recovered from renal venous blood. Analysis for C14O2 of renal venous blood samples, collected anaerobically, showed that less than 0.2% of the injected glucose was converted to carbon dioxide. Urinary excretion patterns of glucose and creatinine were symmetrical, except for a slight delay in the appearance of glucose, during glucosuria from glucose loading and after phlorizin administration. Glucose does not appear to enter the tubule cells from the lumen and subsequently to return to the urine. The transit time of reabsorbed glucose across the tubule cells averages 10 seconds.
Service of urea in renal water conservation
Authors: Crawford John D. , Doyle Antoinette P. , Probst Jan H.
Published: December 2017

Rats allowed water ad libitum were injected with vasopressin tannate in oil to insure formation of maximally concentrated urine. Low protein diet was fed to which were added varying amounts of sodium chloride with or without urea. Through a wide range of urinary excretion rates of nonurea solute the feeding of urea resulted in formation of lesser volumes of more highly concentrated urine. This reduction of the renal water requirement in the urea-fed rats was most marked when the ratio in urine between urea and nonurea solutes had a value of 0.3–0.5. When present in urine in amounts equal to or greater than osmoles of nonurea solute, urea increased the renal water requirement.
Uptake of cortisol in vitro by rat liver mitochondria
Authors: Ulrich Frank
Published: December 2017

The uptake of cortisol by isolated rat liver mitochondria was studied with the aid of the C14-labeled hormone. Evidence is presented which indicates that the hormone enters the mitochondria by diffusion and that the process is extremely rapid. Following incubation, 95% of the cortisol and its metabolites could be removed from the mitochondria by two washings with 0.25 m sucrose. Although submitochondrial particles prepared by disrupting mitochondria either sonically or with desoxycholic acid also accumulated cortisol-4-C14, the uptake was considerably less than that of intact mitochondria. Radioautograms of chromatographed mitochondrial extracts showed that mitochondria metabolized cortisol primarily to compounds more polar than cortisol and that this process was inhibited by 2,4-dinitrophenol and sodium cyanide but not by p-chloromercuribenzoate.
Adenohypophysial corticotrophin and plasma free corticosteroids during regeneration of the enucleated rat adrenal gland
Authors: Fortier Claude , De Groot Jack
Published: December 2017

From planimetric measurements of the total gland and its components, at progressively later intervals following unilateral adrenalectomy and contralateral enucleation in the rat, full regeneration of the cortex was observed to occur within 6–8 weeks. Free corticosteroids disappeared from the plasma within 6–8 hours of the enucleation procedure. Their subsequent rise, already detectable on the 4th day, culminated in a transient and slightly supernormal peak on the 16th day. From a correlation of the plasma free corticosteroid levels to the corresponding amounts of cortex, the secretory activity of the regenerating gland per unit of cortical tissue was estimated at 570% of the paired-weight control base line after 16 days, and at slightly above 200% after 7 weeks, when it leveled off. The pituitary ACTH response to the procedure was characterized by a transient rise within the first 15 minutes, followed by a fall to 35% of the control level after 4 hours, and to 22% after 12, subsequent rise to a crest of 330% on the 16th day, and regression thereafter to near-normal values, recorded on the 184th day. The concomitant rises and falls of pituitary ACTH, cortical secretory index and plasma free corticosteroids, observed in association with cortical deficiency and regeneration, reinforce the conclusion, reached from previous studies, that both release and synthesis of ACTH are accelerated by hypo- and depressed by hypercorticoidism, and that, furthermore, the regulatory effect of steroids is predominantly exerted on synthesis.
Effects of acute and chronic protein depletion and of repletion on serum glycoprotein levels
Authors: Weimer Henry E. , Nishihara Hisako
Published: December 2017

Adult, male, Sprague-Dawley rats weighing approximately 400 gm were fed either a protein-free or a 2% protein diet until they had lost 25% of their weight. Animals from each group were then killed. The remainder were repleted with a diet containing 25% protein. When they had regained their original weight, the rats were exsanguinated. The protein-bound carbohydrates and proteins of whole serum, and of the seromucoid, albumin and globulin fractions, as well as the hemoglobin and hematocrit values of blood were determined. Both acute and chronic depletion caused significant decreases in all serum constituents with the exception of the bound-carbohydrate of the albumin fractions. Upon repletion, significant increases over depletion levels occurred in total serum glycoprotein and protein concentrations due primarily to the elevation of the globulin fractions. Quantitative differences were observed between the response of the acute and chronically depleted groups to repletion but the pattern of change for the major serum fractions was similar for both groups.
Electrocardiographic studies on rats before and after cardiac arrest induced by hypothermia and asphyxia
Authors: Willard Paul W. , Horvath Steven M.
Published: December 2017

Eighteen rats were induced into hypothermia by the closed container technique to determine the effect of extreme reduction of body temperatures on the electrocardiogram. Complete cardiac arrest was obtained for an average time of 44 minutes with periods of ‘suspended animation’ averaging over 90 minutes. Thirty nine per cent of the animals were successfully resuscitated and survived for periods of at least 2 weeks. Andjus ( J. Physiol. 128: 547, 1954.) employing a similar technique for induction of hypothermia was able to secure 50% survival with similar periods of suspended animation but the duration of cardiac arrest in his studies was not stated. Survival could not be predicted from the electrocardiographic record. The ventricular activation time showed an inverse relationship to the temperature. The QTc decreased with cooling and increased with warming. The heart rate decreased exponentially when the rats were cooled and apparently also increased exponentially when warmed.
Effects of intracarotid injections of hypertonic solutions on the neurohypophyseal milk-ejection mechanism
Authors: Holland Robert C. , Cross Barry A. , Sawyer Charles H.
Published: December 2017

A study was made of the effects of elevating the osmotic pressure of the blood flow to the brain by injecting hypertonic solutions into the carotid artery. Stimulation of the release of neurohypophyseal hormone was shown by the occurrence of milk ejection (intramammary pressure rise) corresponding to the effects of intravenous injection of Pitocin (2–20 mu) or Pitressin (10–50 mu). The most favorable conditions for detecting and estimating endogenous hormone release were obtained by transecting the thoracic spinal cord. If the spinal cord was intact the hypertonic injections evoked a sympathetic discharge evidenced by a rise in arterial pressure (eliminated by spinal section), a uterine contraction resembling the response to intravenous injection of 5 µg epinephrine, and an inhibition of the milk ejection response to injected Pitocin. It is concluded that the hypertonic solutions activated nervous mechanisms leading to a release of neurohypophyseal hormone and to a discharge from sympathetic centers in the brain.
EEG correlates of osmotic activation of the neurohypophyseal milk-ejection mechanism
Authors: Holland Robert C. , Cross Barry A. , Sawyer Charles H.
Published: December 2017

A study was made in unanesthetized rabbits immobilized with curare of electroencephalographic (EEG) changes accompanying activation of the neurohypophysis by intracarotid injections of hypertonic saline. The release of neurohypophyseal hormone was monitored by recording the milk-ejection response (intramammary pressure). EEG recordings were obtained from concentric bipolar electrodes placed stereotaxically in various cortical and deep regions of the brain. Every milk-ejection response induced by injection of hypertonic saline was preceded by a brief burst of fast EEG activity in certain areas of the brain. This distinctive EEG activity was recorded most consistently from the deep portion of the olfactory tubercle, and it preceded the calculated time of release of neurohypophyseal hormone by about 10–15 sec. Injections of isotonic saline failed to elicit either the EEG change or the milk-ejection response. It is proposed that osmosensitive elements may lie in or closely related to the olfactory tubercle.
Effect of various psychotomimetic drugs on rate of appearance of carbon-14 in the brains of mice after administration of C14 glucose
Authors: Greig Margaret E. , Gibbons Anna J.
Published: December 2017

The psychotomimetic drugs, bulbocapnine, bufotenine, mescaline, N-methyl-3-piperidyl benzilate, as well as physostigmine and chlorpromazine, decreased the rate of appearance of radioactivity in the brains of mice after either i.v. or i.p. injection of C14 glucose. LSD·25 behaved similarly but the effects were somewhat variable. Atropine, phenobarbital, meprobamate (Miltown), pipradol hydrochloride (Meratran), methylphenidate (Ritalin), hydroxyzine hydrochloride (Atarax), iproniazid and adrenolutin had little or no inhibitory effect. Atropine and amphetamine reversed the inhibitory effects of physostigmine but not of other drugs tested. The psychotomimetic drugs as well as chlorpromazine inhibited pseudo cholinesterase. The possibility that the inhibition of transport is related to inhibition of this enzyme is discussed.
The pH of K-deficient muscle
Authors: Eckel Robert E. , Botschner Andrew W. , Wood Don H.
Published: December 2017

The acid-base balance of muscle from control and K-deficient rats was studied. From the measured buffering capacity, 8–11 mEq excess of anions or deficit of cations would be required to acidify 100 gm fat-free dry weight of muscle, 0.5 pH units. No evidence of increased organic acids, increased anionic equivalence of muscle proteins, or of decreased concentrations of weak bases which are potential cations in cell acidosis was found. This evidence, supplemented with data in the literature, fails to account for the cell acidosis reported in the literature. Reliability of the ‘chloride space’ as a measure of the extracellular phase of muscle in K deficiency has been confirmed by showing its agreement with the ‘raffinose space.’ The cell pH has then been calculated from the distribution of CO2 in muscle (indirect method) and from the pH of muscle homogenates (direct method) in control and K-deficient animals. Control and K-deficient muscle pH's are, respectively, 6.89 and 6.83 by the direct method, and 7.11 and 7.05 by the indirect method.
Thiocyanate space in growing domestic fowl
Authors: Medway William , Kare M. R.
Published: December 2017

The thiocyanate ion was used to measure the extracellular space of the growing chicken. The interstitial space and the intracellular space were calculated. The thiocyanate space was found to be 61.0% of body weight in the 1-week-old chick and 26.2% of body weight in the 32-week-old bird. The interstitial space was 52.3% of body weight in the 1-week-old bird and 21.7% of body weight in the mature hen. The intracellular space was 11.4% of body weight in the 1-week-old bird and 31.1% of body weight in the 32-week-old hen. The thiocyanate space and the interstitial space decreased with age. The intracellular space increased within the age range studied.
Comparative effects of dietary fatty acids and triglycerides on lymph lipids in the rat
Authors: Vahouny George V. , Treadwell C. R.
Published: December 2017

The influence of fatty acids and corresponding triglycerides on the intestinal absorption of cholesterol has been studied in lymph-fistula rats. Butyric and lauric acids, given with bile salt and cholesterol as the free acids or the triglycerides, had little effect on total lymph lipids or on absorption of exogenous cholesterol. Palmitic acid gave a marked increase in lymph lipids which was due entirely to a rise in neutral fat, and a simultaneous depression of cholesterol absorption. The administration of stearic, oleic or linoleic acids produced large increases in the lymph levels of neutral fat and phospholipids. Oleic acid was most efficient, with linoleic and stearic acids somewhat less effective, in promoting cholesterol absorption. The increases in total lymph lipids after tristearin or triolein were less marked than with the free fatty acids, while in the case of trilinolein, total lipids, neutral fat, and phospholipid levels were comparable to the levels after linoleic acid. Of the triglycerides studied, only trilinolein caused a significant elevation of total lymph cholesterol.
Lipid composition of Kupffer cells
Authors: Di Luzio N. R.
Published: December 2017

The St. George procedure was modified to permit the isolation of large quantities of viable, highly purified Kupffer cells and parenchymal cells. Phagocytic cells were isolated from normal dogs and rats by magnetic means following the acute injection of 3-micron spherical iron particles. The phospholipid, total, free and ester cholesterol and total lipids were determined in Kupffer and parenchymal cells. In contrast to the noniron-containing or parenchymal cells, the Kupffer cells of both the dog and rat were characterized by an elevated cholesterol concentration. This difference in cholesterol concentration is due to elevation in both the free and ester fractions. However, the ratio between free, ester and total cholesterol was identical in both the RE cell and the parenchymal cell. These findings suggest a specialized role of reticuloendothelial cells in cholesterol metabolism.
Transmembrane potentials in the rat myometrium during pregnancy
Authors: Thiersch John B. , Landa Jorge F. , West Theodore C.
Published: December 2017

Isolated segments of the uteri of pregnant and nonpregnant Long-Evans rats were studied by the microelectrode technique of intracellular recordings. Both action and resting membrane potentials were recorded in the following states: nonpregnant; 12, 15 and 21 days pregnant; and 24 hours postpartum. The results indicated that the magnitude of the resting membrane potential increased with advancing pregnancy when observed from areas exclusive of the sites of placental attachment. However, resting potentials from placental sites were maximum at 12 and 15 days pregnancy. The frequency of spontaneous spike discharge was greatest in nonpregnant uteri and in early pregnancy declining to a minimum at 24 hours postpartum. Oxytocin increased the frequency of spike discharge and increased the duration of repetitive action potential trains. This effect was greatest in early pregnancy and in the nonpregnant uterus.
Use of levarterenol in treatment of irreversible hemorrhagic shock
Authors: Fozzard H. A. , Gilmore J. P.
Published: December 2017

The effectiveness of levarterenol in the treatment of shock resulting from prolonged oligemia was studied in the dog. The survival time of animals receiving levarterenol and whole blood therapy was significantly greater than that of animals receiving a placebo and whole blood. The results of the experiments indicate that levarterenol is an effective adjunct to whole blood therapy in the treatment of shock resulting from prolonged hemorrhagic hypotension.
Drug-induced changes in blood pressure and in blood sodium as measured by glass electrode
Authors: Friedman Sydney M. , Jamieson James D. , Hinke J. A. M. , Friedman Constance L.
Published: December 2017

By means of a glass-to-silver sodium electrode, the pattern of change in plasma sodium concentration following the administration of pressor and depressor drugs was recorded as a continuous function in a series of seven dogs. The electrode was connected into the femoral artery and its output fed into a Cary vibrating reed electrometer recording through a Grass Polygraph. The pressor response to norepinephrine, epinephrine and angiotonin was regularly accompanied by a fall in electrode potential, indicating a fall in sodium concentration. In terms of degree of change, time course, and duration of effect, each agent produced its own characteristic pattern. The depressor response to acetylcholine, histamine and isopropylnorepinephrine was accompanied by oscillations in the electrode tracing which, in general, tended to be inverse to those observed with pressor agents. The experiments demonstrate that shifts in blood pressure accompany shifts in sodium as recorded by the electrode and thus complement previous observations using blood sampling procedures.
Relation of sympathetic nervous system to blood pressure of bone marrow
Authors: Herzig Edward , Root Walter S.
Published: December 2017

Pressures in the femoral artery and in the marrow of the femur of adult cats anesthetized with Nembutal were measured, using 16 gauge needles and Stratham strain gauge transducers. Records were obtained by means of a Sanborn twin viso, model 60. Bone marrow pressures varied between 24 and 114 mm Hg in different animals. Occlusion of the arterial supply caused a fall in marrow pressure. Stimulation of the cut peripheral end of either vagus reduced both systemic and marrow pressures. Stimulation of the cut peripheral end of the splanchnic nerve, or intravenous injection of epinephrine or norepinephrine, increased systemic arterial pressure and decreased marrow pressure. Stimulation of the peripheral end of the abdominal sympathetic trunk reduced marrow pressure. The increase in systemic arterial pressure produced by occlusion of both carotid arteries is associated with an increase in marrow pressure. Marrow pressures are decreased after a large hemorrhage or when amyl nitrite is inhaled. Unilateral denervation of the blood vessels supplying the femur of a decerebrate cat produces a higher marrow pressure as compared with that present in the contralateral innervated femur.
Latencies of the electroretinogram and optic tectum evoked potentials in the chicken
Authors: Crampton George H. , Boggs Nathaniel
Published: December 2017

The effects of test flash luminance and adaptation level on the latencies of the b-wave and the evoked optic lobe potential are described. There is a striking parallelism between the two activities. The b-wave arises shortly before the evoked potential for all but the very high test-flash luminances where the b-wave follows the tectal response by a narrow margin. The a-wave always precedes any optic lobe activity. Adaptation level, although influencing response amplitudes, has no appreciable effect on latencies.
Stress-relaxation in mammalian gastrocnemius muscle
Authors: Thomson J. D.
Published: December 2017

Rat whole gastrocnemii (ML) and their medial (M) and lateral (L) heads separately, when stretched 5 mm over resting length at rates of 0.29, 1.16 and 4.71 mm/sec., reach slightly higher levels of passive tension with faster stretches, because the faster the stretch the less is ‘give’ able to keep pace with the stretch. Attained tension of L is less than that of M at all stretch speeds, because ‘give’ occurs more readily in L than in M. The faster the stretch the greater the amount of ensuing fast SR, because the less the amount of tension lost by ‘give’ during stretch the greater the amount of tension left to be lost during ensuing fast SR. The faster the stretch the more residual tension left at 180 seconds; the slower the stretch the less residual tension left at 180 seconds. Slow SR appears to be affected very little by speed of stretch. Fast stretch → high attained tension → more fast SR; slow stretch → low attained tension → less fast SR. There is some ‘give’ at fast stretches in both M and L, with M showing more than L. In attained tension and amount of fast SR, M's behavior is modified more by the presence of L than L's behavior is by the presence of M. It is suggested that the contractile component is responsible for fast SR and noncontractile component for slow SR.
Autoregulation of flow in isolated rat kidney in the absence of red cells
Authors: Weiss Christoph , Passow Hermann , Rothstein Aser
Published: December 2017

A method was devised for the perfusion of isolated rat kidney without interruption of flow. The flow pattern obtained with cell-free dextran at a constant pressure showed a stable period of maximal flow for about 15–30 minutes. Thereafter the flow resistance of the kidney increased continuously. Autoregulation was maximal during the period of maximal flow, but thereafter deteriorated until it disappeared completely. The autoregulation was diminished by Priscoline and completely but reversibly abolished by procaine. It was concluded that autoregulation involves a physiological rather than a ‘cell separation’ mechanism.
Urinary excretion by nonionic diffusion
Authors: Scribner B. H. , Crawford M. A. , Dempster W. J.
Published: December 2017

Certain aspects of excretion of some basic amines by a pH-dependent diffusion mechanism have been studied. Dimethylaminoisocamphane, aminoisocamphane, and a new hypotensive agent, pentamethylpiperidine, have been shown to have pH-dependent clearances which are high in acid urine and low in an alkaline urine. If these amines are excreted by a diffusion mechanism their clearances should be independent of the plasma amine level. If pH is kept constant the amine clearance should be increased by an osmotic diuresis. Experimental results conform to these predictions. Taken together, the results make it unlikely that the excretion of these basic amines is carried out by a pH-sensitive transport system. Results are presented which suggest that the amine carried in the red cells may be cleared by the kidney.
Modification of radiation injury in rats through gastrointestinal tract shielding and bone marrow therapy
Authors: Taketa S. Tom , Swift Marguerite N. , Bond Victor P.
Published: December 2017

The efficacy of postexposure administration of isologous bone marrow in preventing mortality was compared in whole-body x-irradiated rats and in animals exposed with three grossly different amounts of the gastrointestinal tract exteriorized and lead shielded. Survival was not enhanced by the therapy in animals which sustained severe intestinal radiation injury and died during the first postexposure week. However, significant protection was afforded by the treatment in animals in which the incidence of acute intestinal radiation deaths was reduced or virtually eliminated by intestinal shielding and deaths in the untreated controls occurred predominantly during the second postexposure week from bone marrow injury. The data demonstrate that bone marrow therapy is effective primarily in preventing deaths associated with radiation-induced damage to the hematopoietic tissue and not to the intestine, and hence its therapeutic value becomes limited as the prominence of intestinal injury increases with increasing radiation dosage in the whole-body irradiated animal.
Statistical properties of spontaneous electrical activity in the MES auditory cortex of the anesthetized dog
Authors: Tunturi Archie R.
Published: December 2017

The spontaneous electrical activity was sampled at 2-second intervals from 50 electrodes on the MES area. Chi-square tests indicated normality for the amplitude values of potential obtained at each electrode. The range for standard deviations was 43–113 µv but averaged between 77 and 85 for three animals. Correlation coefficients greater than 0.7 were obtained between electrodes 2 mm apart in the anterior-posterior direction with a decrement to 0.4 at a separation of 4 mm. Dorso-ventrally, correlations greater than 0.7 were obtained between electrodes 4–6 mm apart, suggesting a strip-like character. Low values of correlation were obtained between an electrode in the MES area and an electrode on the AES or PES area. Assuming independence of the true response and spontaneous electrical activity the mean curve and standard deviation curve of the true response were computed. The standard deviation curve of the true response increased during the positive component gradually decreasing toward the end of the negative component.
Fluid and electrolyte changes of thyroidectomized rats in a cold environment
Authors: Boatman Joseph B. , Walsh John M. , Epstein Leonard I. , Rabinovitz Marvin J.
Published: December 2017

Groups of adult male albino rats were thyroidectomized or sham-operated, and later subjected to 10 day, 5°C cold exposure or else maintained at 22°C room temperatures. Tissues were examined for total water, sodium, potassium, Na24 and I131-thyroxine distribution. Thyroidectomized animals in the cold showed significantly greater amounts of water and Na24 specific activity in muscle and brain. Sham-operated animals in the cold showed significantly reduced brain Na24 specific activity. Thyroxine I131/Na24 ratios in tissue were greater at room temperature in thyroidectomized animals and were decreased with cold. Sham-operated animals showed no differences in brain thyroxine I131/Na24 ratios after equilibration and small differences in muscle ratios, with cold. It was concluded that a cold environment imposed on thyroidectomized animals resulted in changes in the animal's capacity to readjust body fluids and electrolytes when compared with intact animals exposed to cold. These differences were attributable to greater tissue water content and increased sodium flux into the tissues.
Stimulation of cholesterol biosynthesis from acetate in rat liver and adrenals by whole body X-irradiation
Authors: Gould R. Gordon , Bell Virginia L. , Lilly Edith H.
Published: December 2017

Whole body x-irradiation resulted in an increased cholesterol biosynthesis in rat liver and adrenal glands, as measured by the rate of incorporation of either acetate-1-C14 or H3OH in intact animals. The effect was significant 24 hours postirradiation but was much larger at 48 hours, and was proportional to dosage over the range 300–2400 r. In liver the increase in rate was about 100%/100 r. Intestine showed no effect and carcass only a slight increase. Mice showed a small increase in hepatic cholesterol biosynthesis but rabbits and guinea pigs no significant change. Rats injected with both acetate-1-C14 and H3OH gave reasonably constant ratios of C14 and H3 in liver and carcass cholesterol in control and irradiated animals, supporting the hypothesis that the use of acetate-1-C14 in whole animals under standard conditions is a reliable measure of cholesterol biosynthetic rate. The proximate cause of the increased rate of cholesterol synthesis is postulated to be the decreased concentration; in liver a decrease of 0.12 mg/gm was correlated with a doubling of the synthetic rate.
Structural specificity of hexose penetration of rabbit erythrocytes
Authors: Hillman Robert S. , Landau Bernard R. , Ashmore James
Published: December 2017

The penetration of washed rabbit erythrocytes by deoxy and O-alkyl hexoses present at an initial concentration of 20 mm in a phosphate buffer saline solution was tested in vitro. Equilibration of hexoses with intracellular water was calculated from changes in hexose concentration in the medium during incubation. Analysis of cells plus medium indicated no utilization of deoxy and O-alkyl hexoses by red cells. Alterations in the structure of glucose at individual carbon atoms by the preparation of O-methyl and deoxy derivatives was found to have little effect on the permeability of the rabbit red cells to the molecule. The entrance of such compounds was found to be temperature dependent and all of the sugars tested compete with glucose for entrance. Increasing the chain length of the aliphatic substituent on carbon 3 of glucose from methyl to butyl greatly accelerates the rate of penetration. 3-Hydroxyethyl glucose showed the most rapid rate of equilibration with intracellular water of all of the glucose derivatives tested.
Nature of the depressor agent in extracts of rabbit kidneys
Authors: Gordon David B.
Published: December 2017

The nature of the depressor substance in extracts of rabbit kidneys was investigated. In addition to lowering blood pressure the extracts were found to inhibit motility of isolated rabbit intestine, stimulate isolated uterus, cause blanching of rabbit and rat kidney, cause slowing of the heart and prolongation of the P-R interval. These same effects are produced by adenosine and its nucleotides. The depressor substance was shown not to be acetylcholine, choline, histamine or kallikrein. Analysis of the kidney tissue extract by means of column chromatography and measurement of ultraviolet absorption revealed the presence of approximately equal amounts of adenosine mono-, di- and triphosphate as well as lesser amounts of other nucleotides. The amounts of the adenosine derivatives present are sufficient to account for the degree of blood pressure lowering produced by the unfractionated kidney extract. On the basis of this quantitative agreement and the pharmacological effects noted it is concluded that the depressor action of rabbit kidney extract is due to its content of adenosine nucleotides.
Contrasting effects of stress and cortisol overdosage in the rat
Authors: Hall C. E. , Hall O.
Published: December 2017

Page 947: C. E. Hall and O. Hall, "Contrasting effects of stress and cortisol overdosage in the rat." Figure 1 is upside down—and reversed left to right.
Blood corticosteroids and anterior pituitary ACTH and cytology of dogs exposed to hypocapnia and/or hypoxemia
Authors: Biddulph Clyde , Finerty J. C. , Ellis J. P.
Published: December 2017

The concentration of 17-hydroxycorticosterone and a corticosterone-like fraction in peripheral venous blood was not elevated significantly following 15- or 30-minute exposure of dogs to hypocapnia induced by hyperventilation, to hypoxemia induced by breathing 5% oxygen, or to the combination of these conditions. Neither were there significant differences between control and exposed animals in ACTH content of anterior pituitary tissue, or in ascorbic acid content of adrenals. Cytological study of sections of anterior pituitaries revealed somewhat greater than normal acidophilia in all dogs, with the greatest acidophilia being observed in the hypocapnic animals. The concentration of 17-hydroxycorticosterone was higher than that of the corticosterone-like fraction, the 17-hydroxycorticosterone to corticosterone-like ratio varying from 1.3:1 to 1.7:1.
Response of rats with experimental diabetes insipidus to water and salt loading
Authors: Alexander Carl S.
Published: December 2017

Water and salt loading experiments were carried out on normal male rats and rats with chronic diabetes insipidus (DI). The effect of two additional variables has been studied, i.e. that of withholding food and water prior to loading and that of the route of administration of the load (oral or intraperitoneal). Water deprivation prior to water loading reduced the excretion of water by DI animals far below that of normal rats regardless of the route of administration. Salt loading, on the contrary, obviated the influence of prior water deprivation and in every instance DI animals excreted more of the load as compared to controls. The quantitative but not qualitative excretion of both a water and saline load was affected when the intraperitoneal route was used. In both normal and DI rats potassium excretion far exceeded the output of sodium and chloride during water loading regardless of prior food and water deprivation. Desoxycorticosterone acetate (DCA) enhanced sodium excretion in saline loaded hydropenic normal rats but failed to influence sodium excretion in DI rats. Pitressin failed to produce an antidiuretic effect during saline diuresis; however, there was a marked increase in the excretion of salt and potassium in both DI and normal animals.
Oxygen consumption in skeletal muscle during reactive hyperemia
Authors: Yonce Lloyd R. , Hamilton W. F.
Published: December 2017

The surgical technique of isolation of the blood supply of the gracilis muscle of the dog has been developed for analysis of the oxygen consumption during reactive hyperemia. The time course of the blood flow, A-V oxygen difference and the oxygen consumption follow the same pattern. Immediately after the release of the arterial occlusion, there is an increase in all three values which decay and go below the control level that existed just prior to the occlusion. The increased oxygen consumption during reactive hyperemia is possible primarily by the increased blood flow, although the A-V oxygen difference is increased also. A theoretical oxygen deficit is overpaid by the oxygen consumption during the period of increased blood flow but essentially repaid if the period of decreased blood flow is included.
Effect of infusion of rubidium chloride on plasma electrolytes and the electrocardiogram of the dog
Authors: Kunin Arthur S. , Dearborn Earl H. , Relman Arnold S.
Published: December 2017

Infusion of rubidium chloride solutions into anesthetized dogs resulted in rapid cellular uptake of most of the rubidium in apparent exchange for intracellular potassium. Plasma concentrations and renal excretion of potassium rose and there was a progressive fall in plasma bicarbonate. The resultant sequence of changes in the electrocardiogram could be best correlated with the increased plasma concentrations of rubidium plus potassium, and in many respects was indistinguishable from the effects produced by equivalent rises in potassium alone. In half the experiments, however, ventricular irritability seemed to be increased by rubidium, suggesting that this ion does have effects of its own which are different from those of potassium. It is suggested that the greater irritative action of rubidium may be due to a depolarizing effect of intracellular rubidium on the cell membrane.
Atrioventricular transmission in young mammals
Authors: Preston James B. , McFadden Samuel , Moe Gordon K.
Published: December 2017

The hearts of young anesthetized goats, pigs and puppies were exposed for electrical stimulation and recording. Bipolar electrodes were attached to the right atrium and right ventricle. The sinus node was crushed. The heart was driven by stimuli applied to the atrial appendage. At intervals, one or two atrial ‘premature’ responses were induced to assess the time relations of A-V transmission. In all experiments with goats and pigs the earliest possible premature responses, on transmission to the ventricle, yielded electrograms of bizarre configuration. In some preparations multiple responses and ventricular fibrillation were repeatedly induced by early re-excitation of the atrium. Studies of the transmission times of premature responses in the normal and retrograde directions suggested that the refractory period of the A-V transmission system was shorter than that of the ventricle. It is postulated that early premature atrial responses reached the ventricle during its vulnerable period.
C14 studies in carbohydrate metabolism. IV. Characteristics of bicarbonate pool system in the rat
Authors: Shipley Reginald A. , Baker Nome , Incefy Genevieve E. , Clark Richard E.
Published: December 2017

Specific activity curves of expired air were obtained after the injection of NaHC14O3 into normal and alloxan diabetic rats in the postabsorptive and fasted state. The curves were analyzable into three constituent simple exponential functions. This suggested a pool system with three conjoined compartments. The rate of CO2 output being known, pool sizes and rates of carbon movement could be calculated by mathematical treatment of slopes and intercepts. The primary space within which injected C14 equilibrated very rapidly was treated as a single complex pool. Its size was compatible with that of extracellular fluid. Two side-pools were included in the model. The slower moving one had a rate of turnover and size which were greater in the fasted than in the postabsorptive state. This suggests that organic carbon participates in the HCO3– interchange and that CO2 fixation is increased during fasting. No systematic differences between normal and diabetic animals were encountered.
Blockade of hyperkalemia and hyperglycemia induced by epinephrine in frog liver and in cats
Authors: Craig Albert B. , Mendell Philip L.
Published: December 2017

Dihydroergotamine (DHE) and Dibenamine are both known to block the hyperkalemic response to intravenously injected epinephrine. By simultaneously sampling blood from the hepatic vein and from the carotid artery it was possible to demonstrate that these blocking agents act directly on the liver. DHE is also known to decrease the hyperglycemic response to epinephrine, an observation confirmed in the present work. Although Dibenamine is said by some to be ineffective in this respect, we found that it significantly decreased the hyperglycemia. Various dosage combinations of DHE were ineffective in changing the potassium or glucose losses induced by different concentrations of epinephrine administered to the isolated perfused frog liver. Dibenamine also exhibited no effect on the response of the frog liver.
Preparation of chronic denervated gastric pouches in the rat
Authors: Alphin R. S. , Lin T. M.
Published: December 2017

A method is described for the surgical preparation, feeding and care of a chronic denervated gastric pouch in the rat. The basal secretion of the denervated pouch is approximately 0.24 ml/hr. and the hourly free HCl output is nearly zero after a fast of 12 hours. The volume of secretion and the free HCl output both increased after feeding with 3–5 gm of canned dog food. Insulin, 0.5 u, stimulated the output of free HCl from the innervated total gastric fistula but failed to stimulate the volume flow or the acid output of the denervated pouch. A denervated pouch prepared from the squamous or nonglandular portion of the stomach was also described. This portion of the stomach never secreted any free acid at any time over a period of 6 months postoperatively. This is the first physiologic proof that the white portion of the rat stomach is nonacid secreting. The advantages of using a denervated gastric pouch for physiologic and pharmacologic studies are discussed.
Intestinal ischemic shock and the protective role of the liver
Authors: Selkurt Ewald E.
Published: December 2017

A study has been made of the effects of intestinal ischemia of 2 hours' duration on hemodynamics and survival time of mongrel dogs. When the arterial supply to the liver was kept intact during ischemia of the remainder of the splanchnic bed, circulatory collapse ensued at an average time of 7 hours after release of the ischemic compression. When the blood supply to the liver was virtually eliminated, survival was reduced to an average of less than 3 hours ( P = <0.02). The view is favored that the anoxic intestine elaborates a vasotoxic substance, which in the absence of normal liver function invades the systemic circulation with deleterious consequences on the cardiovascular system. The nature of this substance or substances is unknown, as is its specific mode of action.
Incorporation of exogenous choline into liver and biliary phospholipids
Authors: Nakayama Fumio , Johnston Charles G.
Published: December 2017

Since choline is an essential part of biliary phospholipid which has a definite effect on holding cholesterol in solution in bile, the incorporation of exogenous choline into liver and biliary phospholipid has been studied using choline-methyl-C14 and silicic acid column chromatography. Exogenous choline is demonstrated to be rapidly incorporated into liver lecithin, sphingomyelin and biliary lecithin. Indirect evidence is presented showing bacterial degradation of choline in the intestine is not likely responsible for the urinary excretion of large amounts of trimethylamine after oral administration of choline. The choline portion of ingested lecithin is metabolized similar to free choline; ingested lecithin which is absorbed as such from the intestine will remain in general circulation for a considerable length of time.
Effects of physiological levels of thyroxine in vivo on respiration and phosphorylation in rat liver fractions
Authors: Fairhurst Alan S. , Roberts Jane C. , Smith Robert E.
Published: December 2017

Liver mitochondrial systems of varying heterogeneity with respect to microsomal-soluble components were isolated from thyroidectomized and normal rats given l-thyroxine at various dose levels (0, 3, 10, 30, 100, 500 and > 500 µg daily) for 14 days. Degree of homogeneity of fractions was checked by electron and light microscopy. Determinations were made as functions of fraction and thyroxine dose on respiration, phosphorylation, TPNH- and DPNH-cytochrome c reductase activities, DPN content and optical densities. With well washed, homogeneous mitochondrial preparations, stimulation of respiration was obtained without concurrent reduction in P/O ratios, whereas in the more heterogeneous fractions, the qO2OO2 was not elevated, and P/O ratios decreased with increasing dose levels. DPNH- and TPNH-cytochrome c reductase levels were respectively decreased and increased with increasing hormone dosages; the extent of mitochondrial swelling increased, and the DPN content of the mitochondria decreased with dose. The striking change effected by thyroxine on the cytochrome c reductases is at variance with current theory on the regulatory role assigned to the TPNH-DPNH shunt in this respect. Results indicate that thyroxine controls respiration in the mitochondrion directly but that this agent may exert its effects on the phosphorylating activities of the cell by action primarily at some extramitochondrial site.
Significance of the callicrein-callidinogen-callidin system in shock
Authors: Webster Marion E. , Clark William R.
Published: December 2017

Previous investigators have shown that intravenous infusion of partially purified urinary callicrein would reproduce the many features of the shock syndrome. However, infusion of either pancreatic or urinary callicrein prepared by an ethanolic fractionation procedure failed to kill the dogs even when it was given in amounts nine times that previously reported to be toxic. Investigations directed towards the identification of the toxin as measured by earlier studies suggested that a combination of endotoxin and callicrein may have been responsible for the reported lethality. Callicrein is presumed to exert its hypotensive effect by enzymatic action on callidinogen, present in normal plasma, by effecting the release of a polypeptide called callidin. Measurement of the callidinogen content of plasma of dogs killed with endotoxin or by irreversible hemorrhagic shock indicated that small amounts of callicrein may have been released and that these quantities might thus contribute to the death of the animal. The possible synergistic effect and relationship between endotoxin, callicrein and plasmin are discussed.