bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of pH on interaction of calcium ions with serum proteins
Authors: Peterson N. A. , Feigen G. A. , Crismon J. M.
Published: December 2017

A study has been made of the effect of pH on the dissociation of calcium proteinate in rabbit serum. Equations were derived from the experimental data which define a) the effect of serum pH on the McLean-Hastings dissociation constant for the dissociation of calcium proteinate; b) the relationship between the serum pH and the concentration of calcium which is ultrafiltrable; c) the effects of pH, total protein, and total calcium concentration on the change in calcium ion concentration (ultrafiltrable calcium) per unit change in pH. A simple, linear equation was derived from the data which gives serum ultrafiltrable calcium concentration in terms of pH, total protein, and total calcium concentration. A similar study on the dissociation of calcium proteinate was made on purified bovine serum albumin. The results obtained with this system were similar to those obtained on rabbit serum, but the scattering of the data in the case of the purified protein system was far less pronounced. The data on purified albumin was used to re-examine some of the relationships which were derived from the data on rabbit serum.
Effects of ethyl alcohol on EEG and avoidance behavior of chronic electrode monkeys
Authors: Hogans A. F. , Moreno O. M. , Brodie D. A.
Published: December 2017

The electro-encephalogram (EEG) and avoidance behavior of Rhesus monkeys with chronically implanted cortical electrodes, trained on a modified Sidman avoidance schedule, were studied following acute and chronic administration of ethyl alcohol. Acute intravenous administration of alcohol in doses of 0.5–2.0 g/kg produced blood alcohol levels of 50–250 mg/100 ml. As the blood alcohol level was raised, the impairment of avoidance responding was correlated with an increase in signs of central nervous system depression as measured by EEG patterns. A dose of 2.0 g/kg of alcohol was administered intravenously once daily until signs of behavioral deficit were minimal. Initially, avoidance behavior was abolished and spontaneous EEG activity was markedly slowed during the 30-min test period. When tolerance to the behavioral effects of alcohol occurred, the EEG pattern still showed high-voltage, slow-wave activity. This study suggests that tolerance to the behavioral effects of alcohol may be acquired more rapidly than central nervous system tolerance as measured by cortical EEG activity.
Circulation during exercise in normal dogs and dogs with cardiac valvular lesions
Authors: Barger A. C. , Metcalfe J. , Richards V. , Günther B.
Published: December 2017

Cardiac outputs, venous pressure gradients, and femoral A-V O2 differences have been measured at rest and during graded exercise in normal dogs, in dogs with mild valvular lesions, and in dogs with severe failure. In the normal animals a correlation was observed between the rise in cardiac output and the increase in venous gradient, with femoral A-V O2 difference increasing to approximately 14 vol %. In the dogs with mild valvular damage, resting output was not significantly reduced, with a normal venous gradient. Peak output was only one-half to two-thirds of normal, with a similar reduction in venous pressure gradient; femoral A-V O2 difference increased more rapidly than normal, and was significantly higher than normal at exhaustion. The dogs in failure had low outputs and gradients at rest, and were unable to increase them significantly in the mild exercise they were able to perform. Femoral A-V O2 difference at rest was as large as that measured in the normal dog at exhaustion. In both the normal dogs, and those with mild valvular damage, the increments in heart rate during exercise correlated closely with the rise in peripheral venous pressure.
Several relative biological activities of d(–) and l(+) triiodothyronine
Authors: Greenberg Cyrus M. , Bocher Carol A. , Kerwin James F. , Greenberg Samuel M. , Lin T. H.
Published: December 2017

d(–) 3,5,3'-Triiodothyronine administered subcutaneously to intact male rats for 10 days was found to be 0.25 as calorigenic as l(+) 3,5,3'-triiodothyronine. A dose of 15 µg/kg elevated the oxygen consumption of thyroidectomized rats to a level comparable to that obtained for the intact controls. When administered subcutaneously to thiouracil-treated rats d(–) 3,5,3'-triiodothyronine exhibited 0.08 the antigoitrogenic activity of l(+) 3,5,3'-triiodothyronine. A parallel regression analysis of the results obtained from plasma total cholesterol-lowering tests using cholesterol-fed rats or ethyl linoleate-fed mice indicates the need for considering the experimental design when interpreting cholesterol-lowering activity. d(–) 3,5,3'-Triiodothyronine was found to be 0.5 as active as its l(+) isomer in the rat plasma cholesterol-lowering test, while only 0.095 as active in the mouse procedure. Neither agent altered the liver cholesterol of treated mice.
Salt saving in the pregnant rat
Authors: Lichton I. J.
Published: December 2017

Pregnant rats of two strains showed average net accumulation of approximately 83 mEq of sodium/kg of weight gain throughout gestation. Of the total sodium retention, 15, 23, and 62% occurred in each successive third of gestation. Analysis of postpartum sodium balance and of fetal sodium content at term indicated that there was no net accumulation of sodium in the tissues of the dams. Near term, rats given isotonic saline solution showed diminished ability to excrete the administered water in the urine, but showed no impairment in sodium excretion. Serum sodium concentrations were slightly decreased and serum osmolalities were significantly decreased in comparison to values for nonpregnant rats. At term the pregnant rats had greater extracellular fluid volumes than did nonpregnant controls.
Absorption from gastrointestinal tract of the rat after x-irradiation
Authors: Sullivan Maurice F.
Published: December 2017

An in situ perfusion method was used to measure glucose absorption from the x-irradiated or nitrogen-mustard-treated rat. Inhibition was greatest 3 days after treatment and recovery had begun by the 6th day. The effect on absorption was not appreciably different after 900 r than after 1,500 r, although histologic damage was much greater after the higher dose. Pretreatment with cysteine or AET prevented the decreased absorption after 900 r but did not protect against 1,500 r nor against the effect of HN2. The absorption of d(+)-xylose was also decreased 3 days after irradiation of the intestine. Thus, both active and passive transport mechanisms involved in sugar absorption were decreased by irradiation of the intestine. The absorption of fat, on the other hand, was not decreased as a result of direct action by x-radiation on the intestinal epithelium, since oleic acid absorption was unaffected by exposure of the intestine to radiation.
Effect of thyroid hormone on myocardial catecholamine content of the guinea pig
Authors: Goodkind M. Jay , Fram David H. , Roberts Michael
Published: December 2017

Normal and thyroidectomized guinea pigs were subjected to treatment with either triiodothyronine or thyroid-stimulating hormone. Determinations of myocardial catecholamine content and serum protein-bound iodine revealed a significant increase in myocardial norepinephrine content in the markedly thyrotoxic animal, and a significant decrease in norepinephrine content of the myocardium of hypothyroid animals. The significance of these findings in defining the role of catecholamines in various states of thyroid function is discussed.
Leukocyte labeling with inorganic radiophosphorus
Authors: Walker Richard I. , Herion John C. , Palmer Jeffress G.
Published: December 2017

Plasma clearance of inorganic P32 given in a single intravenous injection has been evaluated. Significant levels of activity persist for at least 7 days following injection of only 2 µc/kg. Inorganic P32 uptake into various fractions of circulating leukocytes and into fractions of marrow cells has been studied. In marrow cells, equilibration of extracellular phosphate and intracellular acid-soluble organic and inorganic phosphates appears to be reached by 24 hr and probably occurs sooner. In leukocytes thought to be postmitotic at the time label is injected this equilibrium is not reached until 48 hr. In rabbits the postmitotic maturation pool is sufficient to replace circulating leukocytes for at least 48 hr; this defines the time required for cell passage through this pool under normal conditions. Significant deoxyribonucleic acid tagging from a single intravenous injection of P32 appears to proceed for several days.
Excitation of medullary neurons by chemical agents
Authors: Kim J. K. , Carpenter F. G.
Published: December 2017

Ventilatory responses and certain postural and autonomic responses were studied following injection of isotonic solutions of HCO3-, HPO4-, or citrate into the medullary reticular formation of decerebrated or anesthetized cats. In most respects the responses resulting from any of the three compounds are comparable to the effects of an electric stimulus applied in the same region. Attention was directed primarily to production of a state of ventilatory arrest (apneusis) and/or an alteration in minute volume of ventilation (Ve) by the compounds. Positive responses measured in this way were obtained in roughly 75% of trials. Apneusis in inspiration or expiration was usually followed by either an increase or decrease in Ve. Variations in the pH of the solutions from 6.5 to 8.2 by the addition of CO2 or by HCl failed to alter significantly the ventilatory responses. Also, 1.5% citrate was a less effective stimulus to produce apneusis than 3% citrate, 3.6% phosphate, or 1.3% bicarbonate. After the period of apneusis, ventilation was increased in 55% of trials when 1.5% citrate was used; however, with 3% citrate a decrease in ventilation was more frequently observed. It is proposed that this action of all three compounds is related to their property to reversibly bind calcium ions.
Kidney function, body fluid compartments, and water and electrolyte metabolism in the monkey
Authors: Sweet Avron Y. , Levitt Marvin F. , Hodes Horace L.
Published: December 2017

Standard techniques for measurement of inulin clearance, total body water, inulin space, sucrose space, and T-1824 space were demonstrated to be applicable to normal untrained cynomolgus monkeys. The average of the values obtained are more like man's than are those of any other experimental animal. Normal values were established for plasma sodium, potassium, and chloride concentrations and water, sodium, potassium, and chloride contents of muscle, bone, tendon, cerebrum, medulla, and spinal cord. As reported by others, tissues of low cellularity such as bone and tendon were found to have large quantities of sodium and chloride which could not be assigned to the interstitial fluid. In keeping with the decrease of cellularity of central nervous system tissues from above downward, there was a parallel decrease in potassium and an increase in sodium and chloride contents. These studies provide normal values for salt and water composition of various tissues and fluid compartments and demonstrate the applicability of physiological techniques to the monkey, which is teleologically and apparently physiologically closest to man.
Influence of pH, ionic strength, neutral ions, and thrombin on fibrin polymerization
Authors: Latallo Zbigniew S. , Fletcher Anthony P. , Alkjaersig Norma , Sherry Sol
Published: December 2017

A method for the study of fibrin polymerization as an isolated phenomenon, apart from the over-all reaction of fibrinogen-fibrin conversion by thrombin, is described. Highly purified fibrin monomer, stored at pH 5.3 in 1 m sodium bromide, will polymerize and gel on dilution and pH adjustment. Polymerization rates may be quantitated by serial absorbance determinations at 350 and 600 mµ in a spectrophotometer. The monomer preparation was shown to be free of contaminating fibrinogen or thrombin, and the influence of pH, ionic strength, and neutral ions on its polymerization was studied. The results confirmed the work of previous investigators using less specific methods and indicated that the purified monomer preparation was undenatured. In a recent communication ( Am. J. Physiol. 198: 173, 1960) Landaburu and Seegers reported that thrombin exerted an accelerating or "polymerase" action on polymerization. Polymerization rates determined with the present assay system were found to be uninfluenced by alteration of thrombin concentration and undiminished in its absence.
Carbohydrate requirement of immature nerve fibers during repetitive stimulation
Authors: Carpenter F. G.
Published: December 2017

The compound action potential recorded from chick sciatic nerves was measured at 25 C during 10/sec stimulation after suspension in Ringer's solution containing 3, 10, and 20 mm glucose. Nerves sustained 90–100 min of 10/sec responses after 3 mm glucose, 200–285 min after 10 mm glucose, and 420–510 min after 20 mm glucose. Control responses from paired resting nerves diminished less than 5%. When the nerves no longer conducted impulses (blockade), a 2-hr suspension in 5 mm glucose restored the spike to 90%. Glucose utilization and oxygen consumption by the resting nerves are temperature dependent, but conduction survival is not. Oxygen uptake and glucose disappearance from the nerves were not accelerated by stimulation. Nerves in substrate-free Ringer's which block after 2 hr contain less than 5 µ glucose/ 100 mg nerve, but their oxygen consumption is unchanged. After blockade the nerves studied at 25 C contained 10–25 µ glucose, while at 35 C less than 5 µ was recovered.
Direct adrenergic and cholinergic stimulation of hypothalamic mechanisms
Authors: Grossman S. P.
Published: December 2017

Double-walled cannulas, allowing repeated stimulation of the same site in unrestrained animals with crystalline chemicals, were implanted stereotaxically into the hypothalamus of 36 albino rats. Histological verification of the intended placements showed that the tips of the cannulas were located in an area between the fornix and the mammillothalamic tract, lateral and dorsal to the ventromedial nuclei. Placement of minute amounts of adrenergic substances (epinephrine and norepinephrine) into this area induced vigorous and prolonged eating in satiated animals. Placement of comparable quantities of cholinergic substances (acetylcholine and carbachol) into identical loci in the same animals induced vigorous and prolonged drinking in satiated rats. Adrenergic stimulation increased the food intake of normally hungry animals but decreased the water intake of normally thirsty rats. Similarly, cholinergic stimulation increased the water intake of normally thirsty animals but decreased the food intake of normally hungry animals. Control tests indicated that such side effects of norepinephrine and carbachol as nonspecific activation, osmotic stimulation, vasomotor effects, and changes in the local acid-base composition can be ruled out as potential explanations of the observed results.
Role of manganese and vitamin E deficiency in mouse paralysis
Authors: Lee Y. C. P. , Kuha K. T. , Visscher M. B. , King J. T.
Published: December 2017

Inbred C3H male mice in 20 groups of 10 each were studied to identify the trace mineral element essential to the prevention of "paralysis" in vitamin E deficiency. Cobalt, copper, manganese, and zinc were studied by employing several possible combinations of omissions and additions. Highly purified vitamin E-deficient diets were employed and α-tocopheryl acetate added as the source of vitamin E. It was found that in vitamin E deficiency a concomitant lack of Mn invariably resulted in 100% incidence of early paralysis. Lack of no other element had this effect. After onset of symptoms, additions of vitamin E or Mn, or both, did not reverse the damage, but life spans were increased. The mechanisms of the effect of Mn in protecting against early onset of paralysis in the mouse has not been explained. Body weights were higher in Mn-fed, E-deficient mice than in groups lacking Mn but receiving other minerals.
Oxygen consumption and active transport of ions by isolated frog gastric mucosa
Authors: Forte J. G. , Davies R. E.
Published: December 2017

Isolated bullfrog gastric mucosae were suspended between two glass chambers and bathed with physiological salt solutions equilibrated with 5% CO2 and 95% O2. The transmucosal potential difference, short-circuit current and membrane conductance were measured. Oxygen consumption was measured polarographically and the rate of acid secretion was determined by the pH stat method. Values for the ratio of hydrogen ions secreted to the total oxygen molecules consumed were calculated for 84 experiments and yielded a mean ratio of 1.86 ± 0.51 (sd) with none of the values above 3.5. The ratio of chloride ions transported (calculated as short-circuit current of chloride ions plus hydrochloric acid) to total oxygen consumed for 84 experiments was found to be above 4.0 in 40% of the cases measured (mean 3.80 ± 0.68). A simple redox-pump hypothesis, with molecular oxygen as the electron acceptor, and with one ion moved for each electron transmitted is ruled out as the only operating mechanism to account for active chloride transport by frog gastric mucosa.
Energy cost of work in aerobic and anaerobic turtle heart muscle
Authors: Reeves Robert B.
Published: December 2017

Aerobic rates of oxygen consumption and anaerobic rates of lactate production, each as a function of work rate at 23–25 C, were compared in 75 isolated perfused hearts from turtles ( Pseudemys scripta). Pressure-volume work at constant heart rate was varied over the range of 2–14 x 105 ergs/min. Control experiments established that turtle hearts are capable of sustained (greater than 15 hr) anaerobic work provided some plasma is present in the perfusion medium. Mechanical performance was unaffected by anoxia (pO2 < 2 mm Hg) except for some decrease in heart rate. Adenosine triphosphate (ATP) demand was the same at any given work rate whether the energy was supplied by oxidative phosphorylation or exclusively by anaerobic glycolysis. The efficiency of the heart, expressed as mechanical work divided by free energy consumed, was therefore independent of the metabolic pathways leading to production of ATP. If the Δ F' of ATP hydrolysis is taken to be 7.0 kcal/mole, the efficiency of the working turtle heart is 50 ± 3.4%.
Taste preferences for lithium chloride by adrenalectomized rats
Authors: Nachman Marvin
Published: December 2017

Previous findings had indicated that LiCl and NaCl were similar in taste to the rat. Sodium-deficient adrenalectomized rats were given two-bottle preference tests between the following pairs of solutions: LiCl and H2O, LiCl and KCl, LiCl and NH4Cl, and LiCl and NaCl. Ingestion measures taken during the first few minutes of contact with these solutions indicated that adrenalectomized rats preferred LiCl to H2O, KCl, or NH4Cl and showed no preference between LiCl and NaCl. Long-term measures of intake indicated that rats learned to avoid ingesting LiCl. It was concluded that the preferences of adrenalectomized rats are initially based on the taste of solutions but that the toxic effects of ingesting LiCl produce a learned aversion to this substance.
Transport of electrolytes and water across wall of rabbit gall bladder
Authors: Wheeler Henry O.
Published: December 2017

Gall bladders of rabbits were studied in vitro in an apparatus which permitted measurement of electrical potential difference, net flux of water, and changes in electrolyte concentrations in mucosal and serosal fluid. Net water flux (mucosa to serosa) was directly proportional to net solute transport (measured as sodium flux) and the transported solution was slightly hypertonic. When mannitol was added to the mucosal fluid, water movement occurred against osmotic gradients often exceeding 80 mosmol/kg. Electrical potential differences were small, but the lumen was invariably positive. Flux ratio determinations indicated active transport of both chloride and sodium but not potassium. When isethionate was substituted for chloride, active bicarbonate absorption was also evident. Anion and cation transport were not independent and no transport occurred when choline was substituted for sodium. The evidence suggests coupled active transport of sodium and the major anions. Water movement is dependent upon active solute transport by means of an undetermined coupling mechanism.
Chronic electrical activity of gastroduodenal area: effects of food and certain catecholamines
Authors: McCoy E. J. , Bass Paul
Published: December 2017

A method of implanting electrodes for long-term chronic studies in the gastrointestinal tract of dogs was developed. The electrodes are placed without disrupting bowel continuity, content flow, nerve, or blood supply. They record the two waveforms of electric activity of the gastrointestinal tract (basic electric rhythm (BER) and spike potentials), conduction patterns, and display interrelationships between various segments of the tract. The electrodes were used to evaluate the action of epinephrine, levarterenol, and feeding on the antral-duodenal region. Spike potentials which are associated with contractions were eliminated by the drugs in both antrum and duodenum. The catecholamines initially on infusion, produced arrhythmias in the antral BER and some distortion of the duodenal BER. With continued drug infusion, the frequency of the antral BER was either unchanged or slightly reduced, while the two drugs increased duodenal BER frequency. These differences in response to the drugs suggest that the basic mechanisms which control the electrical rhythms differ in the two organs.
CNS excitability changes during altitude acclimatization and deacclimatization in rats
Authors: Woolley D. E. , Herrero S. M. , Timiras P. S.
Published: December 2017

Electroshock convulsions in rats at sea level and at natural and simulated high altitudes demonstrated a central nervous system (CNS) excitation during acclimatization and depression during deacclimatization. Excitation, shown by decreased minimal seizure threshold and by increased duration of tonic extension during maximal seizures, was evident after 1 or 2 days exposure to 12,500 ft and after 2 hr to 20,000 ft. Changes in maximal seizures disappeared after 2 months at 12,500 ft, but seizure thresholds were significantly lower than in sea level controls even after 8 months. Recovery from maximal seizures remained prolonged and variable at altitude. During deacclimatization after 8 months at 12,500 ft or 6 days at 20,000 ft, CNS depression was shown by absence or shorter duration of tonic extension during maximal seizures and by a rapid rise in seizure thresholds. Increased excitability at altitude is probably due to hypoxia and hyperventilation-induced hypocapnia. The depression during deacclimatization is similar to that produced by hypercapnia and hyperoxia and suggests that CNS sensitivity to CO2 and O2 becomes altered during acclimatization.
Effects of cholinergic drugs on hypothalamic self-stimulation response rates of dogs
Authors: Stark Paul , Boyd Eugene S.
Published: December 2017

The administration of an anticholinesterase agent (physostigmine) which is capable of crossing the blood-brain barrier resulted in a marked and significant increase in threshold and depression of intracranial self-stimulation response rates in dogs with electrodes in the area of the medial mammillary nucleus of the hypothalamus. This effect was not manifested by an anticholinesterase agent (neostigmine) which does not penetrate the blood-brain barrier. The inhibitory action of physostigmine was blocked by the prior administration of an anticholinergic agent (atropine) capable of penetrating the blood-brain barrier, but not by an agent (methylatropine) incapable of penetrating the blood-brain barrier. The level of cholinesterase activity of the serum or red blood cells paralleled the degree of inhibition of self-stimulation response rates. Per cent inhibition of serum cholinesterase activity may be used as an index of per cent inhibition of "true" cholinesterase activity.
Effects of chelating agents on radioiron absorption and distribution in rats in vivo
Authors: Hopping J. M. , Ruliffson W. S.
Published: December 2017

Effects of ethylenediaminetetraacetate (EDTA), citrate, ascorbate, succinate, and sorbitol on the absorption and postabsorptive distribution of Fe59Cl3 in the rat were studied, using an isolated loop technique. Citrate most effectively promoted iron absorption, with ascorbate, EDTA, and succinate following in that order. Sorbitol seemed without effect. Control animals with access to food until time of experiment absorbed more radioiron than did fasted controls. Partial trypsin hydrolysis permitted demonstration that succinate-exposed gut cells most avidly retained iron, while EDTA led to least cellular retention. Postabsorptive distribution among blood, liver, spleen, long bones, kidneys, and urine was unremarkable except that EDTA promoted marked radioiron urinary excretion. EDTA may pass through the gut wall as an intact iron chelate. A pattern of actions during iron absorption is proposed for EDTA, citrate, ascorbate, and succinate.
Comparison of rat liver response to coumarin administered in vivo versus in vitro
Authors: Pool Judith G. , Borchgrevink C. F.
Published: December 2017

Warfarin added to incubated liver slices inhibits the synthesis of factor VII (proconvertin) in proportion to the log of its concentration; surprisingly, it has the same inhibitory effect on the transport and incorporation of amino acid into protein of the liver slices. This latter finding seems to support the frequently proposed concept that vitamin K has a role in oxidative phosphorylation and that coumarin compounds, by antagonizing vitamin K, uncouple oxidative phosphorylation and thus have a general effect on cell energy supply. However, when we studied the liver of rats depleted of vitamin K the same effect was not seen. Liver slices from such animals produced little factor VII but they incorporated amino acid at the normal rate. Furthermore, administration of warfarin in vivo had the same result as vitamin K depletion: a fall in circulating prothrombin complex but no decrease in either labeling of plasma proteins by intravenous C14-amino acid or incorporation of amino acid into subsequently excised liver slices. There is thus a striking discrepancy between the action of warfarin administered in vitro and that administered in vivo.
Alkalosis and renal p-aminohippurate transport in dog: relation to lactate uptake
Authors: Cohen Julius J. , Randall Evelyn W.
Published: December 2017

Does alkalosis per se or does the associated lactacidemia determine the rate of PAH or Diodrast transport? How is net renal uptake of lactate related to Tmpah? Tmpah, renal extraction of I131-Diodrast (Ediod) and net renal lactate uptake were studied in anesthetized (pentobarbital) dogs. In clearance experiments, Tmpah is elevated (facilitated) by isohydric increases in blood [lactate]; alkalosis has no further effect on the facilitated (by lactate) Tmpah. In contrast to the effects of alkalosis on Tmpah, no rise in Ediod occurs during alkalosis. However, when Ediod is depressed by [PAH] sufficiently high to achieve Tmpah, a rise in blood lactate does enhance Ediod. Thus, lactate enhances Ediod when the transport mechanism common to it and PAH is saturated. Net renal uptake of endogenous lactate is decreased during alkalosis; no net renal production of lactate has been observed. Therefore, the increases in Tmpah and Ediod are not related to a rise in net renal uptake of lactate but are probably more related to the blood [lactate]. It is postulated that Tmpah and Ediod may be more dependent on the metabolic mixture presented to the kidney, and thus on extrarenal metabolism, than on intrarenal distribution of blood flow or rate of renal blood flow.
Relationship of hepatic potassium efflux to phosphorylase activation induced by glucagon
Authors: Finder Anthony G. , Boyme Theodore , Shoemaker William C.
Published: December 2017

Hepatic biopsies were obtained from intact, anesthetized dogs before and at 6- to 15-sec intervals after intravenous administration of glucagon. Simultaneously, blood samples were taken from the hepatic vein at 3-sec intervals and the plasma potassium concentration measured. The time course of phosphorylase activation in hepatic biopsies was observed and compared with the time course of potassium release into the hepatic efflux. Measurements were made in normothermic (38 C) animals and in animals subjected to hypothermia (21–25 C). Maximum phosphorylase activation was reached in an average of 79 sec in normothermia and in 144 sec in hypothermia. Maximum hepatic venous potassium concentrations were observed in an average of 41 sec in normothermia and 108 sec in hypothermia. The increased hepatic potassium release which preceded the activation of phosphorylase suggested that electrolyte shifts may be involved in the primary action of glucagon upon hepatic glycogenolytic systems.
Respiration of mitochondria of red and white skeletal muscle
Authors: Blanchaer M. C.
Published: December 2017

Mitochondria of guinea pig red and white skeletal muscle were isolated in a medium containing 0.25 m sucrose, 1 mm ethylenediamine tetraacetate, and 1% fraction V bovine albumin. Oxidative phosphorylation with pyruvate-malate as substrate was tightly coupled in both types of mitochondria when oxygen uptake was measured over a 2- to 4-min period with a platinum electrode. The P/O ratios approached the theoretical value of 3. Oxygen consumption was also determined manometrically with the substrates 10 mm pyruvate—1 mm malate, 10 mm succinate, 6 mm reduced nicotinamide adenine dinucleotide (NADH2), 20 mm dl-lactate, and 12–20 mm dl-α-glycerophosphate. White muscle mitochondria had a higher rate of oxygen consumption with α-glycerophosphate than with lactate, succinate, and NADH2. Those of red muscle were less active with α-glycerophosphate than with the other substrates. These results indicate that an α-glycerophosphate shuttle may couple the reactions generating NADH2 in the cytoplasm of white muscle with the mitochondrial respiratory chain. The properties of the red muscle mitochondria suggest that the direct oxidation of NADH2 may be more important in this tissue than the α-glycerophosphate shuttle.
Action of surfactants on rubidium loss from frog sciatic nerves
Authors: Walsh Raymond R. , Webb George D.
Published: December 2017

Two cationic as well as two anionic and one non-ionized surfactants were examined for their actions in altering the loss of rubidium from frog sciatic nerves that had been previously incubated in buffered Ringer's solution containing a trace of Rb86. All four of the ionic surfactants greatly accelerated the desaturation of Rb86 as compared to the rate of loss from normal nerves which were not exposed to a surfactant. The non-ionic surfactant had very little effect on the Rb loss. There is excellent correlation between the relative effectiveness of the five surfactants in altering the Rb loss and their previously determined action in reducing the A-potential. The data support the hypothesis that cytolytically active surfactants exert disruptive effects on the functional status and molecular morphology of permeability barriers in a nerve trunk such as the frog sciatic.
Efflux of organic acids from rabbit kidney cortex
Authors: Despopoulos Agamemnon , Segerfeldt Åsa
Published: December 2017

Slices of rabbit kidney cortex were equilibrated with selected organic anions. Efflux of substrate from the slices was then observed as a function of time under conditions which emphasized diffusion and minimized energy-dependent reactions. Twenty compounds, including hippurates, benzoates, phenolsulfonphthalein dyes, and sulfonamides, were examined. Rates of diffusion of a variety of organic acids from kidney slices were of a single order of magnitude, ranging from 4 to 12 min. It is, therefore, unlikely that diffusion losses can contribute materially to differences in slice to medium concentration ratios for different substrates. No correlation was observed between the efflux of these compounds and their acidic dissociation constants, their participation in active renal transport, or their partition coefficients between organic solvents and water. Since diffusion of organic acids through renal cortical tissue appears to be independent of their partition coefficients, it is suggested that attempts to explain renal excretory phenomena by the application of the principles of nonionic diffusion should be re-evaluated.
Normal blood volumes in the horse
Authors: Marcilese N. A. , Valsecchi R. M. , Figueiras H. D. , Camberos H. R. , Varela J. E.
Published: December 2017

Blood volumes of 51 horses of three different breeds were determined by means of radioisotopes Cr51 and Fe59. The mean values obtained in 34 determinations for 31 Thoroughbred English race horses are as follows: total blood volume, 10.31; plasma volume, 6.33; and red cell volume 3.98 liters/100 kg body weight for a hematocrit of 42.7%. The results for 6 saddle horses are: 7.75, 5.25, and 2.53, respectively, for a hematocrit of 37.3%. The results in 14 draft horses are: 6.14, 4.35, and 1.82 for a hematocrit of 33.5%. The differences observed in the blood volume values of the three breeds are statistically significant. In our opinion, these differences are due to their physiological qualities, according to the breed.
Intestinal absorption of intrinsic factor and B12-intrinsic factor complex
Authors: Boass Agna , Wilson T. Hastings
Published: December 2017

Evidence is presented which suggests that the vitamin B12-intrinsic factor (B12-IF) complex is absorbed into the intestinal epithelial cell. Following incubation of sacs of hamster ileum with B12-IF complex, the tissue was washed, the mucosa was homogenized and assayed for the complex. The soluble fraction from such a mucosal homogenate was found to possess significant amounts of the B12-IF complex. The exit of vitamin B12 from the basal surface of the epithelial cells was investigated by studying its appearance in the intestinal lymphatics. In a series of rats it was found that 3–9% of the absorbed B12 entered the lymphatic capillaries while the remaining fraction (91–97%) passed into the blood capillaries. Vitamin B12 present in lymph, although not dialyzable, was not bound to intrinsic factor. It is inferred from these studies that B12-IF complex enters the intestinal epithelial cells where it is converted into some other B12-protein complex. Following the exit of this B12-protein complex from the epithelial cell, it enters both lymphatic and blood capillaries, the latter being a quantitatively more important route.
Impulse velocity and conduction pathways in rat myometrium
Authors: Melton Carlton E. , Saldivar Julian T.
Published: December 2017

Velocity of conduction of impulses in rat myometrium is graded with dosage of estradiol cyclopentyl propionate. A single dose of the hormone was given and allowed to act for various periods of time before the animals were killed. Uteri from castrate control animals did not conduct impulses. The earliest effect of the hormone was seen 2 hr after injection, at which time an impulse was conducted with a velocity of 1.25 cm/sec. Velocity increased until 72 hr postinjection when it was 4.65 cm/sec. Uteri from rats 9 weeks postinjcction still conducted impulses at 3.51 cm/sec. Impulses travel on pathways that may be functionally discrete, though one pathway can excite another. Impulses also travel at different velocities on different pathways and it appears that there are bundles of longitudinal muscle fibers directly opposite the mesometrium that conduct faster than adjacent bundles. Pathways must sometimes be facilitated in order for impulses to travel the full length of the uterine horn.
Carotid sinus depressor reflexes during hypothermia
Authors: Kendrick J. E. , Turner Kenneth A.
Published: December 2017

Reducing body temperature in dogs to 24 C caused a small reduction in the size of the carotid sinus depressor response. Along with this reduction the response also became more gradual at the lower body temperatures. Systematic studies demonstrated that the more gradual nature of the response appeared to result from changes in the vascular smooth muscle. Depression of the nervous elements of the baroreceptor reflex arc during hypothermia was not evident. The response to carotid sinus stimulation in the warm, perfused hindlimb was essentially unchanged by cooling the body to 24 C. Local cooling of the perfused hindleg did not reduce the size but did result in a more gradual response.
Heat loss as a factor in the fatal outcome from extensive burns
Authors: Horn Leif , Converse John Marquis
Published: December 2017

Full-thickness thermal injury to 40% of the skin of rats is associated with a homeostatic impairment resulting in fatal circulatory breakdown. Fluid-treated burned rats, given various drug combinations (chlorpromazine, procaine, epinephrine, digitalis, methylandrostenolone), were studied in terms of survival in an environment of 22 C and 40% relative humidity. Drug effects are not reported. Three-fourths of all animals died within 10 days. Irrespective of drug treatments, the most important single factor determining fatal outcome in this study was heat loss, related to the air turbulence in the cages, estimated from the evaporation of water from a calibrated porous surface. The experiments are interpreted to indicate that the caloric loss in these animals exceeds the compensatory capability of the body, and may constitute a major factor in the pathogenesis of burn death.
Differences in displacement of ribs and costal interspaces in rabbits exposed to air shock waves
Authors: Clemedson Carl-Johan , Jönsson Arne
Published: December 2017

The dynamic response of different parts of the chest wall of rabbits exposed to high-explosive shock waves has been recorded by means of a mechanoelectric motion transducer. The costal interspaces were found to be displaced inward with a greater amplitude and in a shorter time than the parts containing the ribs. The correlation of the "rib markings" in lung blast injury to these differences in amplitude are discussed.
Determinants of intramyocardial pressure in the cat
Authors: D'Silva J. L. , Mendel D. , Winterton M. C.
Published: December 2017

Determinants of intramyocardial pressure in the cat were investigated by means of a small latex tube inserted into the wall of the left ventricle. Maximal intramyocardial pressures were generally below carotid systolic pressures. Rhythmic variations in intramyocardial pressure occurred and were related to pulmonary ventilation. There was no evidence of efferent vagal activity on the left ventricle. Sympathetic stimulation increased and sympathetic blockade (with Pronethalol) decreased intramyocardial pressure. Intramyocardial pressure was increased by venous infusions and by constriction of the aorta.
Glucose metabolism and bicarbonate turnover in dystrophic mice
Authors: Baker Nome , Huebotter Robert
Published: December 2017

Hereditarily dystrophic and littermate control mice of the Bar Harbor strain 129 were injected with bicarbonate-C14 to compare rates of turnover of the body bicarbonate compartments. A separate group of dystrophic mice was also injected with glucose-U-C14 to study the turnover and oxidation to CO2 of body glucose. The total glucose pool size was also measured in four dystrophic mice and was found to be 50% greater per unit body weight than that of the previously published mean value for control mice. Since the plasma glucose concentration was the same in both groups, the increased glucose compartment size appears to reflect a relative increase in extracellular space. Specific activity-time curves of respiratory C14O2 were identical in both groups of mice after intravenous injection of bicarbonate-C14. Average values of plasma and whole body glucose specific activity 5–15 min after injection of glucose were lower than, but not significantly different from, those reported previously for control mice. The rate of formation of C14O2 from glucose-C14 was at least as fast in dystrophic mice as in controls. The data indicate that the enzymatic pathways involved in glycolysis, the citric acid cycle, glucogenesis, and gluconeogenesis are functionally active in this disease.
Canine ileal chloride absorption: effect of carbonic anhydrase inhibitor on transport
Authors: Kinney Venard R. , Code Charles F.
Published: December 2017

The rates of movement of chloride and water from ileal loops into blood (insorption) and from blood into ileal contents (exsorption) were determined in dogs by the use of radiochloride and deuterium. The transmural electrical potential was measured. The appropriate values then were applied to Ussing's equation. The data indicated that chloride is actively transported by the ileum of the dog. The addition of acetazolamide (Diamox) decreased the observed transport flux ratio of chloride to a value which was similar to the calculated value for passive transport. It was concluded that acetazolamide inhibited active transport of chloride. When acetazolamide was present, the insorption of chloride was decreased while the exsorption of chloride was not affected. Water transport was decreased in parallel with chloride transport. Determinations of carbon dioxide content of the luminal fluid during the tests suggested that the effect of acetazolamide on chloride and water insorption is not related to its carbonic anhydraseinhibiting action.
Effect of high intra-alveolar O2 tensions on pulmonary circulation in perfused lungs of dogs
Authors: Cropp G. J. A.
Published: December 2017

The resistance to blood flow in the pulmonary circulation of dogs (PVR) increased when their lungs were ventilated with 95–100% oxygen and were perfused with blood that recirculated only through the pulmonary circulation; the systemic circulation was perfused independently. This increase in PVR occurred even when nerves were cut or blocked but was abolished by inhaled isopropylarterenol aerosol. Elevation of intra-alveolar Po2 without increase in pulmonary arterial blood Po2 was sufficient to increase pulmonary vascular resistance. The pulmonary venules or veins were thought to be the likely site of the constriction. These reactions were qualitatively similar to those produced by injection of serotonin or histamine into the pulmonary circulation. The time course of the response and failure to obtain it when the blood was perfused through the remainder of the body before it re-entered the pulmonary circulation are compatible with a theory that high intra-alveolar O2 tension activates a vasoconstrictor material in the pulmonary parenchyma.
Physiologic differences in hemoglobin variants
Authors: Thompson Robert B. , Warrington Richard L. , Bell Warren N.
Published: December 2017

Studies were carried out on whole blood, concentrated hemoglobin solutions, and isolated hemoglobin fractions as related to oxygen association. In hemoglobins Ao, A1, Dalpha, GPhiladelphia, and C, no difference was found in the oxygen association curve. Hemoglobins A1, B2, and Lepore showed a 2½ fold increased oxygen association over normal Hb-A. Hemoglobin solutions from cord blood showed no difference from Hb-A, whereas cord blood showed a twofold increase. Hb-H and Hb-Barts showed identical oxygen association curves with a 10- to 12-fold increase over Hb-A; no heme-heme interaction and no Bohr was found with Hb-H or Barts. Hb-E and Hb-S showed a slight decrease in oxygen equilibria over hemoglobin A.
Potassium movement across serosal and mucosal surfaces of frog gastric mucosa
Authors: Davenport Horace W. , Abbrecht Peter H.
Published: December 2017

Frog gastric mucosa was formed into a sac, filled with 1 ml salt solution and incubated in a large volume of identical salt solution containing 3 mm potassium and K42. Total potassium and specific activities of tissue and fluid were measured at 5, 10, 20, 40, 80, and 160 min after start of incubation. The measurements were repeated on mucosas formed into sacs with the mucosal side out. Both types of sacs were also incubated in solutions containing 0.1 mm histamine. Results confirm observations of others that there is net movement of potassium from fluid bathing the serosal surface into the tissue and mucosal fluid and that histamine stimulates potassium movement from tissue into mucosal fluid. The data were used to calculate the ratio of the rate of movement of potassium across the serosal and mucosal surfaces, Rs/Rm. The numerical value of 4.72 was obtained without histamine and 7.16 with histamine.
An intense hypotensive response evoked by medullary stimulation in the pyramidal cat
Authors: Tuttle Richard S. , Connor Robert S.
Published: December 2017

In the pyramidal cat, point stimulation of the ventral medial portion of the dorsal medulla can result in an intense hypotensive response which may result in death of 10% of the trials or in a prolonged depression of systemic pressure in the remainder. This response was found to result from a cholinergically mediated vasodilatation in combination with a prolonged inhibition of vasoconstrictor tone. The dual hypotensive response does not result from random stimulus spread within the medulla but is rather a distinct vasomotor response. The intensity and duration of the phase of vasoconstrictor inhibition would appear to be a factor in determining the full development of the lethal response.
Renal mechanism for excretion and transformation of arsenic in the dog
Authors: Ginsburg Jack M.
Published: December 2017

Studies have been performed in female dogs on the renal tubular transport of arsenate and arsenite and on the intrarenal conversion of arsenate to arsenite. During the infusion of arsenate there is a net reabsorption of arsenate and a net secretion of arsenite. The rate of arsenite secretion varies directly with the rate of arsenate reabsorption. The transport of both ions is inhibited by phosphate and glucose. Renal arteriovenous concentration differences show a net production of arsenite from arsenate. Stop-flow studies localize the major site of arsenic transport in the proximal tubule. During arsenite infusion both arsenate and arsenite undergo net reabsorption. The data are interpreted as representative of a tubular reabsorption of arsenate with intracellular conversion of arsenate to arsenite and subsequent diffusion of arsenite across both luminal and antiluminal faces of the tubular cell.
Effect of imidazoles on active transport by gastric mucosa and urinary bladder
Authors: Alonso Darwin , Rynes Richard , Harris John B.
Published: December 2017

Studies were undertaken to determine whether the stimulatory effect of histamine and the methyl xanthines on the frog gastric mucosa in vitro could be ascribed to the imidazole component of these compounds. The actively transported ions of gastric secretion appear in the form of hydrochloric acid and of a nonacid chloride component that is responsible for the short-circuit current (Isc). At 10–2 m, imidazole reduced acid secretion (Jh) by 80%, which was somewhat greater than the reduction produced by thiocyanate. N-methylimidazole, 2-methylimidazole, 4(5)-methylimidazole, and benzimidazole abolished Jh. The Isc tended to rise as Jh fell. In stimulated mucosae, imidazole and N-methylimidazole promptly reduced oxygen consumption (qO2) by 25%; thiocyanate had a delayed and lesser effect. Pyrazole, 4-hydroxymethylimidazole, and tris had little or no effect on Jh, Isc, or qO2. Imidazole and N-methylimidazole reduced active sodium transport by the toad urinary bladder by 50%. The results indicate that the inhibitory effects of the imidazoles cannot be ascribed to their buffering capacity or to competitive inhibition of histamine. Instead the effects may result from depletion of tissue content of adenosine-3',5'-phosphate or from interference with protein-bound phosphohistidine in oxidative phosphorylation.