bluuebunny/crossref_metadata_2025 huggingface dataset:
PHOSPHOLIPID METABOLISM IN LIVER SLICES: LABELLING OF PHOSPHOLIPIDS WITH ACETATE-1-C14
Authors: Kline Dorothy L. , DeLuca H. A.
Published: December 2009

A study has been made of the labelling of the phospholipids, the fatty acids from the acetone-soluble lipid, and the non-esterified cholesterol in slices of rat and guinea pig liver respiring in a suitably buffered Krebs–Ringer medium containing acetate-1-C14. The time course of the reactions and the effects of the concentration of potassium ion and the pH of the incubating medium have been defined. For phospholipid and fatty acids of the acetone-soluble lipid, the optimum pH was in the range 6.8–7.4, whereas for cholesterol there was a much sharper optimum at pH 6.6–6.8. When the oxygen of the gas phase was replaced with nitrogen, the labelling of all three lipid fractions was abolished. The addition of glucose to the incubating medium slightly increased the labelling of the phospholipids and the fatty acids of the acetone-soluble lipid, but had no consistent effect on the labelling of the non-esterified cholesterol. Purification of the cholesterol by the method of bromination and debromination caused only a slight change in specific activity, indicating that the cholesterol was not contaminated with large amounts of companion substances with specific activities greatly different from that of the cholesterol itself. The addition of cyanide, fluoride, iodoacetate, or 2,4-dinitrophenol to the incubating medium caused a great decrease in the labelling of all fractions studied. With the exception of 2,4-dinitrophenol, the inhibitors were used in concentrations that inhibit the oxygen consumption. Malonate inhibited the incorporation of acetate-1-C14into cholesterol, but did not affect the labelling of the phospholipids. When the acetate-1-C14was replaced with other C14-labelled precursors, good labelling of phospholipids was observed with glycine-2-C14, glycerol-1-C14, and fructose-C11, but not with formate-C14, lactate-1-C14, or glucose-C14. The cholesterol was not significantly labelled from any of the precursors other than acetate-1-C14.
THE CAUSE OF REFLEX AFTERDISCHARGE IN THE FROG'S SPINAL CORD
Authors: Burns B. Delisle
Published: December 2009

It is usually assumed that spinal reflex afterdischarge in the decerebrate or spinal animal is due to functional circuits of interneurons around which excitation can "chase its own tail" until fatigue brings the process to an end. This hypothesis has been tested in the frog. Reflex afterdischarge of motoneurons innervating the biceps femoris was produced by electrical stimulation of the ipsilateral foot. After the end of reflex stimulation, but during the afterdischarge, a direct single stimulus was applied to the animal's spinal cord. A strength of stimulus (of duration greater than five milliseconds) could always be found which would terminate the afterdischarge abruptly. This strong stimulus did not halt the afterdischarge by producing transient damage to the neurons of the cord, for when the stimulus was given during stimulation of the foot, there was no interruption of either reflex response or afterdischarge. Such experimental results are consistent with Forbes' hypothesis of reverberatory circuits.
A THEORETICAL TREATMENT OF GLUCOSE REABSORPTION IN THE KIDNEY
Authors: Burgen A. S. V.
Published: December 2009

The equations for solute reabsorption in the proximal kidney tubule are derived, assuming Michaelis–Menten type kinetics and linear water reabsorption. Application of the equations to glucose shows that the transport system has a high affinity for glucose, being half saturated at less than 5 mgm. 100 ml. Most of the departure from ideal behavior of the human glucose saturation curve cannot be attributed to an unsaturated transport system. A dispersal of tubule absorptive capacity in a log-normal distribution can account for the curvature of the saturation curve.
THE EFFECT OF PITRESSIN ON THE RENAL RESPONSE TO SALT LOADING IN THE RAT
Authors: Friedman Sydney M. , Webber W. A. , Friedman Constance L.
Published: December 2009

The effect of Pitressin on the renal response to a salt load was studied in normotensive and hypertensive rats. Hypertension was induced by DCA, Compound F, or renal compression. Renal function under load was studied by administering inulin together with a salt load. The effect of 2 I.U. of Pitressin given subcutaneously was studied at two periods, 45 min. and three hours after injection. The first phase of Pitressin action was characterized, as before, by an increase in the excretion of sodium and water. While this was qualitatively similar in all experiments, the degree of response varied greatly, being least evident in rats with Compound F hypertension. The data indicate that a large increase in excretion involves a decrease in the tubular reabsorption of sodium and water. The second phase of Pitressin action was characterized, as before, by conspicuous sodium and water retention. This retention can be explained as a reflection of changes in the filtered load which might in turn be due to a change in renal hemodynamics or to a minor decrease in plasma sodium and water.
CREATINE PHOSPHOKINASE ACTIVITY OF MAMMALIAN ERYTHROCYTES
Authors: Solvonuk P. F. , McRae Sheila C. , Collier H. B.
Published: December 2009

Creatine phosphokinase activity was demonstrated in hemolyzates of rabbit and rat erythrocytes, but it was not present in significant amounts in human erythrocytes. Activity of the enzyme was followed by photometric estimation of the creatine liberated in the transfer of phosphate from creatine phosphate to adenosine diphosphate. The enzyme was inhibited by mercurials, heavy-metal ions, and iodoacetate, and evidently possesses free thiol groups. It required for its activation a divalent cation, such as Mg++ or Ca++, but neither Na+ nor K+ had any effect.
THE MECHANISM OF DEGRADATION OF A CELLODEXTRIN BY MYROTHECIUM CELLULASE
Authors: Whitaker D. R.
Published: December 2009

A cellodextrin with a number-average degree of polymerization (D.P.) of 24 was hydrolyzed by Myrothecium cellulase in the presence of C14-labelled cellobiose. The specific activities of cellotriose and cellotetraose isolated at various stages of the hydrolysis were less than 20% of that of cellobiose isolated at the same time. It is concluded that transfer reactions involving cellobiose contributed little to the formation of cellotriose and cellotetraose. The ratio moles of cellotriose formed/mole of cellobiose formed was at least 0.7 and the corresponding ratio for cellotetraose at least 0.4. The number-average D.P. of the substrate decreased slightly during the hydrolysis. The results exclude a degradation of the substrate by cleavage of cellobiose units from the ends of its chains but are consistent with degradation by random cleavage.
POLYHYDRIC ALCOHOL PRODUCTION BY OSMOPHILIC YEASTS: STUDIES WITH C14-LABELED GLUCOSE
Authors: Spencer J. F. T. , Neish A. C. , Blackwood A. C. , Sallans H. R.
Published: December 2009

D-Glucose was dissimilated aerobically by a strain of osmophilic yeast producing glycerol, D-arabitol, ethanol, carbon dioxide, and a small amount of succinic acid. Glucose-1-C14 gave glycerol labeled in the terminal carbons, D-arabitol labeled in carbon-1 and carbon-5, methyl labeled ethanol, and succinic acid with 30% of the labeling in the carboxyl carbons and 70% in the methylene carbons. Glucose-2-C14 gave glycerol labeled in carbon-2, D-arabitol labeled in carbon-1, carbon-2, and carbon-4, carbinol labeled ethanol, and succinic acid having 70% of the labeling in the carboxyl carbons and 30% in the methylene carbons. Labeled carbon dioxide was produced from both carbon-1 and carbon-2 labeled glucose but the specific activity of carbon dioxide from glucose-1-C14 was higher than that from glucose-2-C14. The distribution of radioactive carbon in the products is explained by assuming that glucose is dissimilated via a combination of the Embden–Meyerhof and the phosphogluconate oxidation pathways, with transketolase-catalyzed reactions playing an important part in D-arabitol formation.
C14O2 ASSIMILATION IN LILIUM REGALE WITH REFERENCE TO γ-METHYLENEGLUTAMIC ACID
Authors: Wickson Margaret E. , Towers G. H. N.
Published: December 2009

It was found that γ-methyleneglutamic acid, γ-methylglutamic acid, and their keto-acid analogues are natural constituents of Lilium regale. These compounds were not present in the seed but appeared soon after germination. It was shown that, in seedlings, these compounds are not formed from atmospheric carbon dioxide either in the light or in the dark. This was shown also for excised leaves under a variety of conditions. In entire young plants a synthesis of γ-methyleneglutamic acid was demonstrated in the bulbs and roots. The keto-acid analogue was synthesized in all parts of the plant including the leaves. The results suggest that the accumulation of γ-methyleneglutamic acid in leaves is through transport from the subterranean organs of the plant where it is synthesized.
STUDY OF ADRENOCORTICAL PHYSIOLOGY IN JET FLYING
Authors: Murphy C. W. , Cleghorn R. A.
Published: December 2009

A statistically significant eosinopenia occurred on days on which jet aircraft were flown in the mornings. The difference between experimental and control days was more marked in the early part of the afternoon than in the later part. The absolute values for urinary corticoid excretion were not shown to be significantly different on experimental days by comparison with control days, but when expressed in terms of corticoid excretion/body surface area they were seen to be significantly greater on the mornings of experimental days by comparison with control days. Corticoid/body surface area was not constant for different individuals. Salivary electrolyte concentration did not differ significantly on experimental days as compared with control days, but the late afternoon hour at which the single specimen was collected may have missed any change occurring earlier.
PHOSPHORUS METABOLISM OF THE ADRENAL GLAND OF THE RAT: EFFECT OF EXPOSURE TO A COLD ENVIRONMENT FOR EIGHT DAYS ON THE AMOUNTS AND P32-LABELLING OF PHOSPHOLIPID AND RIBONUCLEIC ACID
Authors: Nicholls Doris , Heagy F. C. , Rossiter R. J.
Published: December 2009

The incorporation of inorganic phosphate labelled with P32 into the lipid P and ribonucleotide P of the adrenal glands of rats exposed to cold (3 ± 1 °C.) for eight days was measured 16 hr. after the P32 injection. In the cold-exposed animals, there was a decrease in the specific activity of both the lipid P and the ribonucleotide P and also a decrease in the specific activity of the lipid P and the ribonucleotide P relative to that of the inorganic P of the adrenal. The cold exposure caused an increase in the amounts of lipid P, ribonucleic acid (RNA), and desoxyribonucleic acid (DNA) per pair of adrenals. There was an increase in the ratio lipid P: DNA-P, but no change in the ratio RNA-P: DNA-P. Calculation showed that the cold exposure caused a decrease in the percentage renewal rate of both lipid P and ribonucleotide P, most of which could be attributed to the increased amounts of lipid P and ribonucleotide P present at the beginning of the isotope experiment. However, when allowance for this was made by calculating the renewal rates of the P of the phospholipid and RNA per pair of adrenals, the values remained slightly less in the cold-exposed animals.
THE EFFECT OF DIHYDROSTREPTOMYCIN ON THE FORMATION OF BETA-GALACTOSIDASE BY ESCHERICHIA COLI
Authors: Polglase W. J.
Published: December 2009

In confirmation and extension of previous observations on the effect of dihydrostreptomycin on adaptive enzyme formation, it was observed that the formation of the enzyme β-galactosidase was inhibited by dihydrostreptomycin in a strain of Escherichia coli which could not multiply in the presence of this antibiotic. Formation of β-galactosidase was not inhibited in E. coli variants which could multiply in the presence of dihydrostreptomycin or which required the antibiotic for multiplication.
ADAPTIVE ENZYME FORMATION BY DIHYDROSTREPTOMYCIN- DEPENDENT ESCHERICHIA COLI
Authors: Polglase W. J. , Peretz Susan , Roote Susan M.
Published: December 2009

An apparent requirement for dihydrostreptomycin for the formation of adaptive enzymes has been demonstrated in a strain of E. coli which requires this antibiotic for cell multiplication. The effect of dihydrostreptomycin on the formation of adaptive enzymes by E. coli has been shown to be consistent with the effect of the antibiotic on bacterial multiplication.
STUDIES ON THE EFFECTS OF PHAGOCYTIC STIMULATION ON MICROBIAL DISEAS: VI. SOME FACTORS DECREASING PHAGOCYTIC ACTIVITY OF MONOCYTES AGAINST TUBERCLE BACILLI, STRAIN BCG
Authors: Kátó László , Gözsy Béla
Published: December 2009

An antihistamine if present in a concentration of 0.1 to 100 μgm. per ml. decreased considerably the in vitro phagocytic activity of normal monocytes. The stimulated phagocytic activity of monocytes by histamine or 1,4-dimethyl-7-isopropyl-bicyclo-decapentane was antagonized by the antihistamines. Monocytes withdrawn from antihistamine treated animals showed a markedly lesser phagocytic activity than monocytes from untreated animals. The results are discussed from the point of view of the mechanism of action of 1,4-dimethyl-7-isopropyl-bicyclo-decapentane in experimental tuberculosis.
COMPARATIVE BIOCHEMICAL STUDIES ON NORMAL AND ON POLIOMYELITIS INFECTED TISSUE CULTURES: III. ENZYME ASSAYS ON HOMOGENATES OF SURVIVING NORMAL RHESUS KIDNEY. EFFECT OF SYNTHETIC NUTRIENT MIXTURES
Authors: Kovacs Ernest
Published: December 2009

Investigation of enzyme systems in normal tissues is the main subject of this communication. The activity of phosphatases, nucleotidases, and nucleases was explored in "brei" prepared with water, physiological salt mixtures, and synthetic media used for tissue cultivation, to compare the influence of these diluents. The depression of acid phosphatase by medium 597, noted previously in cells growing in vitro, was confirmed in fresh tissue and definitely proved on purified enzyme. Alkaline phosphatase was activated by the same synthetic medium. Differences in kinetics were observed when the effect of medium 597 was examined on 5-nucleotidase concentrate of Russel's viper venom and on pentanucleotidase of fresh kidney. Crystalline RNA-se was inhibited, in a manner similar to the nucleases of kidney extracts. Both phosphomonoesterases were enhanced by the less complex nutrient 697. The deterioration of DNA-se in medium 199 upon storage was striking. Significant observations were gathered on enzymes of concentrated and very diluted (1: 1600) tissue homogenates, on extracts, and on isolated enzymes of various grades of purity.
KINETIC STUDIES ON THE HYDROLYSIS OF BENZOYLCHOLINE BY HUMAN SERUM CHOLINESTERASE
Authors: Kalow W. , Genest K. , Staron N.
Published: December 2009

Benzoylcholine stands out from other known substrates of serum cholinesterase because of its high apparent affinity for this enzyme combined with a rapid rate of destruction. The reaction kinetics of the hydrolysis of benzoylcholine can be studied by ultraviolet spectrophotometry, since the absorbance decreases in proportion to the concentration of substrate. Kinetic data obtained by measuring initial reaction rates, and by analyzing continuous hydrolysis curves, are the same within the range of experimental error. The enzymatic data are compatible with the assumption that in the presence of high substrate concentrations a complex consisting of esterase and two substrate molecules is formed. This complex is hydrolyzed more slowly than the complex containing one molecule of substrate which is formed at low concentrations of benzoylcholine. Alkaline hydrolysis of benzoylcholine follows the kinetics of a first order reaction.
THE EFFECT OF THE SARINASE LEVELS OF LIVER ON THE SURVIVAL OF RABBITS INJECTED WITH SARIN
Authors: Adie Peter A.
Published: December 2009

The effect in rabbits of the sarinase levels of liver and plasma, and of cholinesterase levels of plasma on survival after repeated intraperitoneal or subcutaneous doses of sarin has been investigated. When the intraperitoneal route was used a significant correlation was found between liver sarinase and survival. Survival after subcutaneous injection was not affected by the liver sarinase. No correlation was found between plasma sarinase or plasma cholinesterase and survival for either the intraperitoneally or subcutaneously injected rabbits.
THE METABOLISM OF γ-HYDROXYGLUTAMIC-α-C14 ACID IN THE INTACT RAT
Authors: Benoiton Léo , Bouthillier L. P.
Published: December 2009

Synthetic γ-hydroxyglutamic-α-C14 acid was found to be extensively catabolized in the intact rat and to give rise to both labelled glutamic and aspartic acids. The results obtained are in agreement with a previously proposed theory that γ-hydroxyglutamic acid may be converted to glutamic and aspartic acids by two distinct metabolic routes. The fact that only a small amount of radiocarbon was found in the tissue hydroxyproline suggests that the conversion of γ-hydroxyglutamic acid to hydroxyproline, if it does occur, is of minor importance.
THE ACTION OF FACTOR I ON CERTAIN INVERTEBRATE ORGANS
Authors: Florey Ernst
Published: December 2009

Factor I, prepared from beef brain, has been applied to a number of invertebrate organs and physiological preparations. It was found to antagonize the effect of acetylcholine in some preparations while it imitated it in others. The discussion of the results of this investigation as well as of previous findings leads to the assumption that factor I may be classified with the many pharmacological agents which affect cholinergic mechanisms and that it is likely to be a transmitter substance of inhibitory neurons.
PAROTID SECRETION OF IODIDE
Authors: Ferguson Marion H. , Naimark A. , Hildes J. A.
Published: December 2009

Parotid juice from normal human subjects was collected by means of suction cups over the parotid papillae. The iodide content of the secretion was determined at various flow rates with and without the oral administration of potassium iodide, ammonium thiocyanate, and methimazole (Tapazole, Lilly), as these drugs are known to influence iodide metabolism in the thyroid gland. An inverse curvilinear relationship was found between the concentration of iodide and the rate of parotid secretion. Potassium iodide by mouth increased the concentration of parotid juice iodide in the same proportion as the increase in blood level of iodide. The amount of iodide secreted by the parotid glands was depressed by the administration of thiocyanate but was not influenced by the administration of methimazole.
THE EFFECTS OF CONVULSANT AGENTS ON PARTIALLY ISOLATED REGIONS OF THE CENTRAL NERVOUS SYSTEM
Authors: Drake C. G. , Seguin J. J. , Stavraky G. W.
Published: December 2009

The effects of removal of one motor cortex, a frontal lobe, or a complete cerebral hemisphere on the action of various convulsant agents were studied in chronic cats and in spinal preparations. In both sets of experiments, previously decentralized neurons responded to smaller quantities of convulsant drugs than did the intact ones, and pentylenetetrazol, camphor, and picrotoxin, as well as strychnine and acetylcholine, evoked greater and more prolonged responses from these neurons when sufficient time was allowed for sensitization due to partial isolation to take place (in the majority of experiments two to eight months).This was ascertained in myographic recordings and in studies of the electrical activity of the anterior horn cells in high spinal cats and white rats, as well as in photographic and statistical analyses of convulsions induced in chronic animals. The latter study revealed that the convulsions were asymmetrical in the operated cats, the muscular contractions being exaggerated and prolonged contralaterally to the cerebral ablation. The median convulsant dose (CD50) of pentylenetetrazol for the control cats was 7.8 mgm./kgm. (95% confidence limits 7.4–8.1) while that for the operated group was 6.8 mgm./kgm. (95% confidence limits 6.3–7.2). The latent period following the injection of pentylenetetrazol was significantly shorter for the operated group than for the control one, and the convulsions lasted longer in the operated cats than in intact animals. The longer duration of convulsions in the operated group depended on a significantly longer tonic and terminal clonic phase of the convulsion. Two patterns of convulsions could be elicited—a clonic and a more severe clonic–tonic–clonic (CTC) one. In the control group clonic convulsions were more frequent at low dosages of pentylenetetrazol while CTC convulsions pre-dominated at high dosages. In the operated group CTC convulsions were prevalent throughout the range of doses used and occurred in a greater percentage of animals than in the control group. Chemically induced convulsions play a prominent part in the study of epilepsy and in the treatment of some mental derangements, and it is felt that this investigation may contribute to the understanding of the mechanism of action of convulsant agents on the nervous system in which abnormal conditions prevail.
LIPOTROPIC DOSE–RESPONSE STUDIES IN RATS: COMPARISONS OF CHOLINE, BETAINE, AND METHIONINE
Authors: Young R. J. , Lucas C. C. , Patterson Jean M. , Best C. H.
Published: December 2009

Dose–response curves have been obtained showing the effects, in weanling rats, of graded doses of choline, betaine, and methionine, respectively, when added to a hypolipotropic diet. A comparison of the lipotropic activity made on the steep portions of the dose–response curves showed that at all liver fat values from normal to 27%, the ratio of betaine to choline necessary to produce a given level of fat was 3: 1. Essentially similar ratios were observed in the prevention of hemorrhagic kidney lesions and in the stimulation of growth. Methionine, at the lower doses, was as effective as betaine, on a molar basis, in maintaining a given level of liver fat. However, the higher levels of methionine were not as efficient. Methionine at the highest dosage used did not bring the liver fat entirely within the normal range.
CARDIOVASCULAR EFFECTS OF PENTOLINIUM BITARTRATE IN DOGS
Authors: Spoerel W. E. G. A. , Gowdey C. W.
Published: December 2009

Pentolinium (5 mgm./kgm.) injected intravenously into dogs anesthetized with pentobarbital caused the pulse rate to approach that of dogs with surgical cardiac denervation. The higher the initial pulse rate, the greater the decrease after the drug; rates under 100/min. were increased. Changes in arterial pressure followed a similar pattern, and the changes in both systemic and pulmonary arterial pressures were correlated with the changes in pulse rate. The cardiac output was decreased. Pressor responses to injected adrenaline and noradrenaline were greater after pentolinium. Total peripheral resistance, respiratory rate, respiratory minute volume, and oxygen consumption were not changed significantly, but local (hind-leg) resistance was decreased in two of three experiments. Pentolinium abolished or reduced markedly the cardiovascular responses to reduced carotid sinus pressure, tilting, acute hypoxia, large doses of acetylcholine, and hemorrhage. The cardiac vagus and the cardiovascular part of the sympathetic nervous system are blocked, but the experiments suggest that the adrenal medulla may not be completely blocked by 5 mgm./kgm. pentolinium.
THE EFFECT OF INSULIN ADMINISTRATION ON ARTERIOVENOUS GLUCOSE DIFFERENCES IN THE ALLOXAN-DIABETIC DOG
Authors: Gray Doris E. , DeLuca H. A.
Published: December 2009

It has been reported by others and confirmed by the present workers that following the intravenous administration of insulin in the normal animal, the glucose concentration in venous blood may exceed that of arterial blood giving rise to a negative arteriovenous difference. The simultaneous administration of glucose enhances this effect. The present investigators have extended this work to the alloxan-diabetic animal (dog) and have shown that large negative arteriovenous blood glucose differences are obtained following administration of insulin and glucose. These differences are too great and too consistent to allow the contention that negative arteriovenous differences are simply the result of analytical errors.
STUDIES OF LIGNIN BIOSYNTHESIS USING ISOTOPIG CARBON: V. COMPARATIVE STUDIES ON DIFFERENT PLANT SPECIES
Authors: Brown Stewart A. , Neish A. C.
Published: December 2009

Seven species of higher plants have been tested for their ability to convert radioactive tyrosine to lignin in vivo. A total of 11 species representing 10 families have now been compared and only Triticum vulgare and Calamagrostis inexpansa, both members of the Gramineae, have given positive results. It is suggested that lack of a specific enzyme system may prevent lignin formation from tyrosine in the other species. The metabolic differences appear to be restricted to tyrosine utilization, for both wheat and maple have similar abilities to use a number of labelled cinnamic acid derivatives, as well as phenylalanine. Further evidence is presented that each type of lignin polymer has a corresponding aromatic monomer. Sinapic acid, ferulic acid, and probably p-hydroxycinnamic acid are preferentially transformed to syringyl, guaiacyl, and p-hydroxyphenyl lignins respectively.
REGIONAL DIFFERENCES IN THE GLUCAGON CONTENT OF PANCREAS FROM ALLOXANIZED DOGS
Authors: Bencosme Sergio A. , Mariz S.
Published: December 2009

The uncinate process of the dog pancreas is devoid of A cells. Pancreatic extracts from the uncinate process of alloxanized dogs showed neither hypernor hypo-glycemic activity. These findings suggest that the lack of hyperglycemic effect of extracts from the uncinate process of the normal dog pancreas (11) simply indicates absence of glucagon and is unrelated to the presence of insulin. These results are in agreement with the hypothesis that glucagon is originated by the A cells of the pancreas. Neither the D nor X cells showed any sign of damage following alloxan injection during the period of observation.
FURTHER STUDIES ON THE METABOLISM OF UROCANIC-α-C14 ACID
Authors: Kraml M. , Bouthillier L. P.
Published: December 2009

The existence of radioactive metabolites in the liver extracts of rats a short time after injection of urocanic-α-C14 acid has been investigated. Glutamic acid, N-formiminoglutamic acid, and an unknown compound that yields glutamic acid on hydrolysis were the major urocanic acid catabolites found therein. These three substances accounted for as much as 75% of the total radiocarbon in the extracts. The sole catabolic pathway of importance for urocanic acid, in the rat, is the formation of glutamic acid. Since formylglutamic acid could not be detected in these extracts, the role of this substance as an obligatory urocanic acid catabolite becomes questionable.
HEMODYNAMIC CHANGES FOLLOWING AORTIC CONSTRICTION IN NORMAL AND IN HYPOPHYSECTOMIZED RATS
Authors: Beznák Margaret
Published: December 2009

Systolic and diastolic blood pressures were measured electrically, during ether anesthesia, in the carotid and femoral arteries at different times after subdiaphragmatic aortic constriction in normal and hypophysectomized rats. In normal rats there is a rise in both systolic and diastolic pressures above the stricture, followed by a transitory drop, then a gradual increase to hypertensive levels. Below the constriction the pressure falls sharply with a great reduction in pulse pressure, but rises to values above normal in a few days. In hypophysectomized rats the initial changes parallel those in normal rats, but the rise of the blood pressure to hypertensive levels both above and below the stricture is absent. Left ventricular hypertrophy develops from about the second day on in normal but not in hypophysectomized rats. After constriction there is a small decrease in heart rate followed by a pronounced tachycardia in normal but not in hypophysectomized rats. There is some indication of an increased subdiaphragmatic peripheral resistance in hypophysectomized rats.
HEPARINASE: III. PREPARATION AND PROPERTIES OF THE ENZYME
Authors: Cho M. H. , Jaques L. B.
Published: December 2009

The extraction of heparinase from beef and rabbit liver has been studied. Optimal conditions for precipitation of the enzyme were 33% ammonium sulphate, pH 7.0; 7% ethanol, pH 5.0–5.5; 40–70% acetone, pH 8.0; with 0.1% NaCl for ethanol and acetone. A new method of preparation of the enzyme is described, using extraction with 0.15 M KCl, precipitation with 33% ammonium sulphate, isoelectric precipitation at 6.0, elution at 37 °C, and precipitation at 5.0. This preparation gave a 50% destruction of heparin in three hours. The optimum pH was 4.8, substrate concentration, 0.2 mgm./ml. Higher concentrations inhibited the enzyme. A linear relation was not obtained between enzyme concentration and velocity of the reaction. The enzyme was inhibited by mercuric chloride, magnesium chloride, lithium chloride, iodoacetate, glutathione, methionine, versene, and citrate. In liver homogenates, the enzyme activity was associated with all fractions (microsomes, mitochondria, etc.). Active preparations were obtained from liver of man, ox, pig, rabbit, guinea pig, rat, gopher; kidney of ox, pig, rabbit, guinea pig, and rat; muscle of rabbit and guinea pig. No activity was obtained from dog liver, ox testis and thymus, human placenta. Difficulties in assaying heparinase in tissue extracts are discussed.
THE INFLUENCE OF THIOURACIL ON THE RESPONSES OF SERUM PROTEIN AND SERUM CALCIUM OF THE IMMATURE PULLET TO ESTROGEN, WITH SOME OBSERVATIONS ON THE RESPONSES OF OVIDUCT, LIVER, AND KIDNEY
Authors: Wright L. A. , Maw W. A. , Common R. H.
Published: December 2009

Thiouracil at a level of 0.75% of the diet depressed the serum calcium and serum protein levels of sexually immature pullets that had received 0.5 mgm. estradiol benzoate (ODB) intramuscularly each day for nine days or 14 days. When the level of estrogen dosage was raised to 1.0 mgm. ODB each day, then in one experiment thiouracil did not appreciably affect the responses of serum calcium and serum protein at nine days but did enchance both responses at 14 days. In a second experiment thiouracil again exerted a depressant effect on responses of serum calcium and serum protein at nine days but this effect had disappeared at 14 days. Thiouracil tended in both experiments to reduce the serum protein level in unestrogenized pullets. The effects of thiouracil on responses of serum calcium and serum protein are dependent, therefore, on both the level and duration of estrogen treatment. Thiouracil did not modify the effect of either 0.5 mgm. or 1.0 mgm. ODB per diem on oviduct weight. Estrogen increased liver weight per kgm. live weight and liver protein per kgm. live weight and thiouracil produced similar effects. These effects of estrogen and thiouracil were approximately additive. Estrogen increased kidney weight per kgm. live weight. Thiouracil increased kidney weight per kgm. live weight both of itself and in presence of estrogen. Kidney protein per kgm. live weight was affected by thiouracil and by estrogen in the same ways as was kidney weight.
IMMEDIATE EFFECTS OF RAPID HEMORRHAGE ON HEMODYNAMICS IN THE DOG
Authors: Waud Russell A. , Waud Douglas R.
Published: December 2009

Dogs were anesthetized by the intravenous injection of sodium pentobarbital. Viscosity, hematocrit, blood pressure, cardiac index, stroke output, cardiac output, heart rate, peripheral resistance, red blood cell count, blood volume/body surface area, cell volume/area, plasma volume/area, plasma protein, hemoglobin, specific gravity of whole blood, cell size, color index, and sedimentation rate were determined in 16 dogs, before and following hemorrhage, and in seven controls. The following points were demonstrated: following hemorrhage the viscosity, hematocrit, blood pressure, stroke output, minute output, blood volume, and cell volume were markedly decreased. The decrease in blood volume, by limiting the venous return, was probably the cause of the decreased minute output and fall in blood pressure; this, by reducing the capillary flow, deprived the tissues of an adequate supply of oxygen. There was no significant change in the heart rate. The total peripheral resistance (T.P.R.) was greatly increased. The fall in hematocrit indicates a hemodilution which was probably the main factor in reducing the viscosity. It would appear that the decreased blood volume was the primary cause of the fall in blood pressure following hemorrhage and that a lowering of viscosity was not a large factor. There was no significant change following hemorrhage in the cardiac index, color index, cell size, white cell count, specific gravity of plasma, or sedimentation rate.
ELECTROLYTE METABOLISM IN THE RAT EXPOSED TO IONIZING RADIATION
Authors: Baker D. G. , Sellers E. A.
Published: December 2009

Some observations concerning electrolyte metabolism in rats subjected to single doses of X irradiation and to prolonged exposure to gamma irradiation are described. Blood electrolyte changes were slight even when severe radiation damage was present. During prolonged exposure to gamma irradiation at 60 roentgens per 24 hr. the adrenal glands first increased in weight then decreased to the pre-exposure values. This may represent a type of adaptation to slowly administered irradiation. Balance studies on rats exposed to gamma irradiation at a dose rate of 60 roentgens per 24 hr. showed a small loss of sodium, potassium, and chloride during the initial period of the exposure. During the remainder of the exposure period the sodium and chloride remained nearly in balance although the body weights decreased. Potassium balance remained negative during the exposure. The stability of the electrolyte composition of the blood and of electrolyte balance, in the presence of widespread damage which results from irradiation, is considered highly significant.
FATTY ACID INHIBITION OF CHOLESTEROL SYNTHESIS
Authors: Wood J. D. , Migicovsky B. B.
Published: December 2009

Fatty acids inhibit cholesterol synthesis by rat liver homogenates. Inhibition occurs with acids containing either an even or an odd number of carbon atoms in the chain, and with saturated and unsaturated acids, the inhibition increasing with the degree of unsaturation of the acid. In the case of acids with an even number of carbon atoms the inhibition increases with chain length to a maximum at 12 carbons after which a rapid decrease occurs. The presence of fatty acid during cholesterol synthesis increases the acetate incorporated into fatty acids to a slight extent. This increase is small compared with the decrease in the amount incorporated into cholesterol. A possible mechanism for the inhibition is discussed.
RESIDUAL AIR DETERMINATION
Authors: Kovach John C. , Baker Earl , Etebar Hamid
Published: December 2009

A simple method is presented of revealing and calculating any "switch-over" error in the determination of the residual lung volume. Our method is shown of avoiding the possibility of error in the alveolar nitrogen sample caused by the creation of a negative pressure in a patient with a low expiratory capacity. Through the use of tables a simplified method of accurately calculating residual volumes is presented.
THE POTASSIUM UPTAKE AND RATE OF OXYGEN CONSUMPTION OF ISOLATED FROG SKELETAL MUSCLE IN THE PRESENCE OF INSULIN AND LACTATE
Authors: Manery J. F. , Gourley D. R. H. , Fisher Kenneth C.
Published: December 2009

Insulin (5.0 × 10−2 units per ml.) and lactate (5.0 × 10−3 M) caused an uptake of potassium by intact frog skeletal muscles in vitro, and a concomitant loss of potassium from the medium surrounding the muscles; this fluid was Ringer's solution containing 2.1 meq. of potassium per liter. Thus a movement of potassium against a high concentration gradient has been demonstrated. In general, the conditions under which potassium uptake occurred stimulated the oxygen consumption of the muscles. Monoiodoacetic acid (2.5 × 10−4 M) abolished the effect of insulin on the potassium uptake and greatly reduced its effect on the oxygen consumption.
EXPERIMENTAL EVALUATION OF DIURETICS IN THE RAT
Authors: McColl J. D. , Parker J. M. , Ferguson J. K.W.
Published: December 2009

The diuretic response of the male and the female rat to aminophylline has been studied when these animals were pretreated with various concentrations of sodium chloride solution. A linear log dose – response curve was obtained over the dose range employed with male rats pretreated with 0.45% and 2% saline. Male rats exhibited a diuresis with 4% saline which was not increased by aminophylline. Female rats showed diuresis but the responses were more variable for almost all combinations of electrolyte load and xanthine dose. When they were pretreated with 0.45% and 2% saline, aminophylline caused some additional production of urine but this was much less regular than that observed with males. The variation in response to aminophylline after 4% saline was very marked but the trend suggested that the xanthine had a diuretic effect at the high dose. The diuretic responses to a xanthine, a mercurial, and a carbonic anhydrase inhibitor type of diuretic were compared in the male rat. Peak responses were smallest after the mercurial diuretic and greatest with the carbonic anhydrase inhibitor.
METABOLISM OF ADRENAL STEROIDS IN THE MOUSE: 1. OBSERVATIONS ON 20α-DIHYDROCORTICOSTERONE AND CORTICOSTERONE IN THE PLASMA OF MICE TREATED WITH CORTICOTROPIN
Authors: Southcott C. M. , Bandy H. E. , Newsom S. E. , Darrach Marvin
Published: December 2009

Plasma levels of corticosterone and 20α-dihydrocorticosterone increase in the mouse following the administration of corticotropin. These are the two most abundant C21Δ4-3-keto adrenal steroids in mouse plasma. The evidence indicates that some, if not all, of the circulating 20α-dihydrocorticosterone represents a tissue metabolite of corticosterone. A procedure is outlined for the synthesis of 20α-dihydrocorticosterone.
THE METABOLISM OF THE ERYTHROCYTE: XIV. METABOLISM OF NUCLEOSIDES BY THE ERYTHROCYTE
Authors: Rubinstein David , Denstedt Orville F.
Published: December 2009

Adenosine, added to blood, undergoes deamination in the red cells with the formation of inosine. The latter undergoes phosphorolysis to yield hypoxanthine and presumably ribose-1-phosphate. The pentose phosphate is metabolized to lactate yielding ATP in the process. The adenosine deaminase and the purine riboside phosphorylase of the red cell occur in the stroma-free hemolyzate. No adenine is formed from adenosine in the blood, nor is adenine metabolized by the erythrocyte. Xanthosine, guanosine, and inosine, added to blood, follow the same metabolic pathway as adenosine and their metabolism brings about a comparable degree of resynthesis of ATP and other organic phosphate esters and formation of lactate. The experimental evidence indicates that the phosphorolysis of the nucleoside is not the rate-limiting reaction in the metabolism of these compounds in the red blood cell.
BLOOD GLOBULINS REDUCING THE ANTICOAGULANT ACTIVITY OF HEPARIN
Authors: Triantaphyllopoulos Demetrios C.
Published: December 2009

The effect of serum and plasma pseudoglobulins on the prolonged thrombin and prothrombin time of heparinized plasma was studied. It was found that pseudoglobulins are able to shorten thrombin time and to a lesser degree prothrombin time. Experiments suggest that the following mechanism is involved: Pseudoglobulins replace heparin cofactor from heparin – heparin cofactor complex and, because the new complex acts as a weak antithrombin, the pseudoglobulins seem to possess antiheparin activity. Since euglobulins too have a weak antiheparin effect, no specificity can be ascribed to this phenomenon. Serum pseudoglobulins shorten also the prolonged thrombin time of incubated plasma, but not the prolonged prothrombin time. Plasma pseudoglobulins, however, because of their content in labile factor shorten both thrombin and prothrombin time.
HEMATOLOGICAL AND BODY FLUID ADJUSTMENTS DURING ACCLIMATION TO A COLD ENVIRONMENT
Authors: Deb C. , Hart J. S.
Published: December 2009

Body fluid volumes and hematological values have been compared in rats exposed to 6 °C. for various periods of time and in rats at 30 °C. for comparable periods. Absolute blood and plasma volumes (T1824 space) decreased with time of exposure to 30 °C, while extracellular fluid volume (sodium space), total body water, and body weight increased. Rats transferred from the warm to the cold environment had larger plasma and blood volumes than those of rats at 30 °C. after the first week of exposure. After five weeks, blood volume was 22% greater on an absolute basis and 30% greater relative to total body water than that of the larger rats at 30 °C. There were no differences in extracellular fluid volumes between warm and cold exposed rats at comparable intervals. Total water and intracellular water tended to be greater in rats at 30 °C. on an absolute basis but they were much greater per unit body weight in rats at 6 °C. No differences were observed in red blood cell counts, in hemoglobin concentration, or in plasma specific gravity between warm and cold exposed rats, but there was an increased hematocrit, increased corpuscular volume, and decreased corpuscular hemoglobin content in rats kept at 6 °C. Hemoglobin, red cells, and plasma specific gravity increased with time in both groups.
HYDROLYSIS OF GLYCEROLPHOSPHATIDES BY PLASTID PHOSPHATIDASE C
Authors: Kates Morris
Published: December 2009

Studies of the influence of structural variation in the glycerolphosphatide molecule on the hydrolysis of this class of compounds by plastid phosphatidase C showed that the presence of both fatty acid ester groups is necessary for enzymatic reaction; that release of nitrogenous bases occurred, in the presence of ethyl ether, from phosphatidyl cholines, phosphatidyl ethanolamine, and phosphatidyl serine; and that a phosphatidyl choline was hydrolyzed more rapidly than the corresponding phosphatidyl ethanolamine or phosphatidyl serine. The rate of hydrolysis of phosphatidyl choline was influenced greatly by the chain length and degree of unsaturation of the fatty acids. The corresponding phosphatidic acid formed in the hydrolysis of (dipalmitoyl)- or (dipalmitoleyl)-lecithin by carrot phosphatidase C was isolated. Studies on the hydrolysis of crude soybean phosphatide by phosphatidase C showed that both choline and ethanolamine were liberated in the absence of ethyl ether, at an optimum pH of 4.8; in the presence of ether, the rate of liberation of each base was increased, and the pH optimum was between 4.8 and 6. Soybean phosphatide probably contains a substance that stimulates the enzymatic hydrolysis.
THE EFFECT OF ORAL AND INTRAVENOUS ADMINISTRATION OF VITAMINS K ON THE PROTHROMBIN AND PROCONVERTIN LEVELS OF CHOLECYSTNEPHROSTOMIZED DOGS
Authors: Fisher L. M. , Millar G. J. , Jaques L. B.
Published: December 2009

Six dogs were prepared with permanent biliary fistulae by cholecystnephrostomy. Chronic bile lack in these animals led to the development of a bleeding tendency and to a significant drop in the levels of proconvertin and prothrombin. A comparison was made of the relative effectiveness of the K-vitamins administered orally and intravenously in restoring the plasma levels of prothrombin and proconvertin. Vitamin K3 (2-methyl-1,4-naphthoquinone, menadione) and Synkavite (2-methyl-1,4-naphthohydroquinone diphosphoric ester tetrasodium salt) were found to be more effective and rapid in returning prothrombin and proconvertin values to normal than vitamin K1 (2-methyl-3-phytyl-1,4-napthoquinone) when given orally on an equimolar basis. Intravenously vitamins K1, K2 (2-methyl-3-difarnesyl-1,4-naphthoquinone), K3, and Synkavite had approximately the same molar biological activity in the immediate correction of prothrombin and proconvertin levels but the effect was less prolonged in the case of vitamin K3, and was only transient with Synkavite. Observations were made of pathological changes in the livers of these animals.
FACTORS AFFECTING THE POTASSIUM CONTENT OF INCUBATED BRAIN SLICES
Authors: Pappius Hanna M. , Elliott K. A. C.
Published: December 2009

When rat cerebral cortex slices are incubated in glucose–saline medium in the presence of oxygen, the slices lose half of their potassium almost immediately and then reconcentrate it to some extent. Uptake of potassium proceeds further if glutamate is added to the medium but, since the apparent intracellular space is also increased by glutamate, the intracellular potassium concentration is not increased by glutamate. The difference between the potassium concentrations in the incubated slice and in the medium reaches a maximum when the medium contains about 5 mM potassium. In the absence of oxygen, under ordinary conditions, slices lose potassium rapidly but the final concentration reached remains higher than that of the medium and this difference is marked if the concentration in the medium is high. The greatly depleted potassium content of slices which have been incubated anaerobically can be largely restored by subsequent aerobic incubation. The rate and extent of this restoration decreases with the length of time during which the slices have been deprived of oxygen. If the medium contains pyruvate or if the slices have been subjected to a previous period of aerobiosis, anaerobic glycolysis is stimulated and concomitantly the potassium concentration in the slices increases. The effects of pyruvate and previous aerobiosis are additive. The sum of sodium and potassium in slices incubated under various conditions does not vary greatly but the sum is significantly increased in the presence of glutamate, in phosphate instead of bicarbonate-buffered medium, and, especially, in medium containing a high potassium concentration. The fluid taken up in swelling has approximately the same total cation content as that of the medium.
THE PURIFICATION OF SARINASE FROM BOVINE PLASMA
Authors: Adie P. A.
Published: December 2009

The purification of bovine plasma sarinase has been carried out using alcohol precipitation methods and ultracentrifugation. A protein solution was obtained which was 1250 times more active per unit weight of protein than the original plasma. Sixty per cent of this activity was lost on freeze-drying. The electrophoretic pattern of the preparation showed that the material was apparently homogeneous.
THE ENZYMATIC REDUCTION OF TETRAZOLIUM SALTS BY AMINES
Authors: Lagnado J. R. , Sourkes T. L.
Published: December 2009

An enzyme system effecting the dehydrogenation of amines has been detected in rat brain and liver suspensions by the use of tetrazolium dyes as terminal electron acceptors. Kinetic data on this system are presented and the evidence for requirement of a cofactor is described. Thus, after washing or dialysis, rat brain suspensions have a considerably lowered tetrazolium reducing activity, which can be restored by addition of boiled extracts of rat liver, rat brain, pig liver, or baker's yeast. The heat-stable cofactor in pig liver and rat brain which is necessary for the activity of the tetrazolium reducing system is dialyzable. Pig liver extracts lose their cofactor activity on ashing. The nature of the electron transporting system active in amine dehydrogenation is discussed and the properties of the tetrazolium reducing and the amine oxidase systems are compared.
SIZE, STABILITY, AND HETEROGENEITY OF APURINIC ACID
Authors: Wood G. C. , Smith David B.
Published: December 2009

Apurinic acid prepared by mild acid treatment of sodium desoxyribonucleate and of fractions of sodium desoxyribonucleate was sufficiently stable to permit estimations of molecular weight and polydispersity. Apurinic acid from unfractionated desoxyribonucleate had a weight-average molecular weight of 25,000 and was very polydisperse. Preparations from fractionated desoxyribonucleate representing about half the original nucleic acid were much less polydisperse and had molecular weights of about 10,000.