bluuebunny/crossref_metadata_2025 huggingface dataset:
STUDIES ON ALDOSTERONE: III. CHRONIC EFFECT ON THE BLOOD PRESSURE OF RATS
Authors: Gornall A. G. , Grundy H. M. , Koladich C. J.
Published: October 2017

A rise in systolic blood pressure due to the administration of 0.4 or 0.5 μg of aldosterone per 100 g body weight to young male rats, over a period of 3 to 6 months, has been confirmed in two separate experiments. This effect was observed whether the aldosterone was given 3 days a week or 6 days a week, and whether dissolved in aqueous ethanol or in oil. Equal doses of 9-α-fluorohydrocortisone and of 2-methyl-9-α-fluorohydrocortisone produced similar though somewhat less consistent effects. When 4 or 5 μg of reserpine was administered along with aldosterone there was no clear evidence of a protective effect. Reserpine alone at these low dose levels was somewhat toxic in the rat and led to a rise in blood pressure.
THE TAC METHOD OF TRYPTIC ENZYME ACTIVITY DETERMINATION
Authors: Ronwin Edward
Published: October 2017

A new, practical, and quantitative method for the determination of tryptic enzyme activity is reported. The method is based on measurements of the U.V. absorption of the complex formed between cupric ion and Nα-p-toluenesulphonyl-L-arginine, the latter being the product of the reaction between the tryptic enzymes (thrombin, trypsin, plasmin) and the corresponding methyl ester. Comparisons with the null point titration procedure demonstrate the new method's superiority when dealing with enzyme–substrate reactions in concentrated buffer solutions. Under certain conditions, it could also be superior in dilute buffer situations. The effects of pH and cupric ion concentration on complex formation are discussed along with other characteristics of the U.V. absorption curves of the complex.
PREPARATION AND PROPERTIES OF TRANSKETOLASE FROM PORK LIVER
Authors: Simpson F. J.
Published: October 2017

Transketolase of pork liver has been purified 90-fold and separated from ribulose 5-phosphate 3-epimerase. The transketolase is most stable between pH 7.5 and 8.5 and below 40 °C. The pH range for optimum activity is between 7.6 and 8.1. Activation by magnesium ions or thiamine pyrophosphate could not be demonstrated, but thiamine pyrophosphate increased the stability of the enzyme. Sulphydryl agents, such as p-chloromercuriphenyl sulphonic acid and N-ethylmaleimide, and heavy metal ions, such as cupric, mercuric, and zinc, at relatively high concentrations inhibited the enzyme.
ELECTROLYTE METABOLISM IN THE RAT EXPOSED TO A LOW ENVIRONMENTAL TEMPERATURE. II
Authors: Baker D. G.
Published: October 2017

Rats acclimatized to cold (2 °C) have lower subcutaneous tissue and superficial muscle temperatures than comparable animals living at 25 °C. The total water content of the skin is significantly increased after acclimatization to cold. This increase is due to an increase in the chloride space. The total water content of muscle was decreased in the rats acclimatized to cold although the chloride space (extracellular water) was increased. The intracellular sodium of muscle was decreased by exposure to cold.
ANTIFUNGAL ACTION OF SALICYLANILIDE. II
Authors: Baichwal R. S. , Baxter R. M. , Kandel S. I. , Walker G. C.
Published: October 2017

The fungistatic activities of certain compounds structurally related to salicylanilide suggest the possible involvement of hydrogen bonding of the anilide hydrogen atom and chelation by the phenolic and amidic oxygen atoms with an enzyme(s)/enzyme system of the fungus. The inhibition of enzymes has been followed through the development of specific color reactions on salicylanilide assay plates. The participation of sulphydryl groups in the mechanism of action is suggested by these tests.
THE AMINO ACID CONTENTS OF HORSE GLOBIN AND OF ITS COMPONENT POLYPEPTIDES
Authors: Habeeb A. F. S. A. , Smith David B.
Published: October 2017

Horse globin and its component polypeptide chains obtained by fractional precipitation and column chromatography have been analyzed for their constituent amino acids. The principal difference between the two chains is that the valyl-leucyl chain is rich in serine and threonine and poor in glutamic acid and tryptophan compared to the valyl-glutaminyl chain.
THE SULPHYDRYL CONTENT OF β-LACTOGLOBULIN
Authors: Habeeb A. F. S. A.
Published: October 2017

The reaction of sulphydryl groups of β-lactoglobulin with N-ethylmaleimide, p-chloromercuribenzoate, and iodoacetic acid has been studied. Using N-ethylmaleimide with native and sodium dodecyl sulphate denatured protein, a value of 2.3 groups of sulphydryl per mole of protein was obtained. A value of 2.15 moles of sulphydryl per mole of protein was obtained from reaction with p-chloromercuribenzoate but lower values were obtained after urea denaturation. The reaction of iodoacetic acid was followed by the determination of residual sulphydryl by the p-chloromercuribenzoate method.
AN ELUTER FOR PAPER CHROMATOGRAMS
Authors: Saffran M. , Sharman D. F.
Published: October 2017

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PAPER ELECTROPHORESIS OF SERA AND PLASMA FROM CHICKS AFFECTED WITH ERYTHROBLASTOSIS
Authors: Darcel C. le Q.
Published: October 2017

Plasma and sera from normal and leukemic (erythroblastosis) chickens have been studied with the aid of paper electrophoresis. Differences are more easily demonstrable with pH 6.4 phosphate buffer than with barbiturate buffer. There is a relative depression in serum albumin and an apparent 'shift' in the positions normally occupied by the α- and β-globulins. The latter regularly appear to move as one band in electropherograms of sera from leukemic birds. It has been possible to induce this 'shift' in normal sera by storage or incubation.
STUDIES ON THE NUTRITIONAL VALUE OF DEFATTED FISH FLOUR
Authors: Morrison A. B. , Campbell J. A.
Published: October 2017

In studies on the nutritional value of defatted fish flour, groups of male weanling rats were given otherwise adequate diets containing 7%, 10%, or 15% protein supplied by fish flour or casein. After 4 weeks, protein efficiency ratio (P.E.R.) values found for 7% and 10% fish flour were significantly higher than those for comparable levels of casein, but similar values were found for both proteins at the 15% level. The kidneys of the animals given diets containing 15% protein were significantly heavier than those of the animals fed the other diets, but level or source of dietary protein had no significant effects on liver and adrenal weights, or liver lipid levels.In further studies, fish flour was added to whole wheat flour or to white bread prior to baking, and the resulting mixtures were fed to growing male rats at the 10% protein level. Addition of 2, 4, or 6 lb of fish flour per 100 lb of whole wheat flour increased the P.E.R., in a stepwise manner, from 1.49 to 2.80 but had no effect on organ weights or liver lipid levels. Addition of 10% fish flour to white bread made with or without 4.2% milk solids increased the P.E.R. values by 82%, and 198% respectively, and significantly decreased liver lipid levels. The P.E.R. values for bread and flour diets were found to be a direct function of the lysine content of the protein.It was concluded that defatted fish flour is an excellent source of high quality protein, and should be of particular value in supplementing diets deficient in lysine.
STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: XII. UTILIZATION OF SERINE-C14WITH SPECIAL REFERENCE TO GLYCINE LABELLING
Authors: Nath R. , McConnell W. B.
Published: October 2017

Serine-C14(uniformly labelled) was injected into the top internode of wheat plant stems and the distribution of carbon-14 in the mature plants (harvested 24 days after injection) was studied. Fifty-six per cent of the carbon-14 injected was found in upper plant parts but only trace amounts occurred below the top internode. The kernels contained 48% of the tracer injected while only 4% remained in the stem. Gluten had the highest specific activity of any major kernel component, serine and glycine accounting for one third of the total carbon-14 of the protein. The high specific activity of serine in gluten indicates its direct incorporation into kernel proteins. The specific activity of the glycine was almost equal to that of serine. Since similar experiments with glycine-1-C14have yielded gluten with highly radioactive serine-1-C14, the ready interconvertibility of these two amino acids is demonstrated. The results indicate that interconversion takes place, at least in part, by the reversible condensation of "active" formate with carbon-2 of the glycine but that alternate pathways may also operate.
OXIDATION OF SULPHYDRYL GROUPS IN DENATURED EGG ALBUMIN
Authors: Tsen C. C. , Tappel A. L.
Published: October 2017

The oxidation of dry denatured egg albumin and dry myosin by molecular oxygen indicates that the direct oxidation of dry proteins containing free sulphydryl groups is a general reaction. Cupric ion was the most effective catalyst for the oxidation of denatured egg albumin in solution. The rate of the oxidation was measured as a function of cupric ion concentration, pH, and temperature. Since the catalytic oxidations of denatured egg albumin, glutathione, and cysteine have very similar activation energies, the mechanism of copper-catalyzed sulphydryl oxidation may be the same for the three compounds. Under the conditions studied, only sulphydryl groups of denatured egg albumin were oxidized. The oxidation of these groups proceeded beyond the disulphide stage.
THE ACTION OF NORMAL AND ATYPICAL CHOLINESTERASE OF HUMAN SERUM UPON A SERIES OF ESTERS OF CHOLINE
Authors: Davies R. O. , Marton A. V. , Kalow W.
Published: October 2017

The results of a comparison of the actions of individual human sera support evidence previously obtained for the existence of two different types of pseudocholinesterase in man. Maximum rates of hydrolysis of choline esters by human sera containing the normal type of cholinesterase were two to four times greater than the maximum rates obtained with sera containing atypical esterase. Human sera with the normal type of cholinesterase hydrolyzed butyrylcholine at a considerably faster rate than pentanoylcholine; atypical esterase hydrolyzed pentanoylcholine at approximately the same rate as butyrylcholine. All Michaelis constants for the normal enzyme were lower than those for the atypical enzyme by a factor which varied from 1.4 to 6.4. The data were compatible with the assumption of a linear relationship between the log of the Michaelis constants and the number of acyl carbons in the choline esters, but the slopes differed significantly for the two enzymes. For a homologous series of choline esters, there was no correlation between rates of hydrolysis and Michaelis constants.
BIOSYNTHESIS OF QUERCETIN IN BUCKWHEAT: PART III
Authors: Watkin J. E. , Neish A. C.
Published: October 2017

The effect on the conversion of carbon14 to quercetin by a buckwheat plant caused by variation in the dose rate of a carbon 14-labelled precursor in μmoles over a 100-fold range has been studied. The results expressed as dilution of carbon14 varied over a 200-fold range for the same precursor with most of the variation being found at low dose rates. When expressed as the percentage of administered carbon14 converted to quercetin the results for acetate, D-glucose, and L-phenyllactic acid were mostly constant over this range but L-phenylalanine had a maximum percentage conversion or an optimal dose rate. An explanation of the results in metabolic terms has been attempted.It is recommended that the "percentage of C14 converted" be used to express results in plant biosynthetic work.
A MICROMETHOD FOR THE DETERMINATION OF SULPHATE BY FLAME PHOTOMETRY
Authors: Robinson G. A.
Published: October 2017

A micromethod for the determination of 0.1 to 3.5 μg of sulphate is described. Acidified barium chloride solution is added to samples containing free and esterified sulphate, and the resultant mixtures are dried at 95 °C. Soluble materials are redissolved with a 90% solution of acidified ethanol, 0.1 N for hydrochloric acid, containing 250 μg lithium per milliliter. After addition of the ethanol solution, approximately eight hours are required for the establishment of equilibrium (as indicated by a radiosulphur label) between solid and dissolved barium sulphate. Barium present in solution is then determined quantitatively by flame photometry, with the ethanol–lithium medium increasing the primary emission of the barium by 15 times. The sulphate content of the sample is read from a standard curve. Estimations on microgram quantities of some organic and inorganic sulphur-containing compounds are given.
ACETYLASPARTIC ACID AND AMMONIA POISONING
Authors: Ruisseau Jean-Paul Du
Published: October 2017

Acetylaspartic acid has been followed in nine tissues of normal and ammonia-poisoned rats. This acetylated amino acid is present at high concentrations in normal brain and remains unchanged in ammonia-poisoned brain. Acetylaspartic acid is absent or present in trace amounts in normal liver. It increases appreciably in ammonium acetate poisoning, reaching a peak at death. No change in concentration was detectable in the other tissues examined. There is a correlation between aspartic and acetylaspartic acid in the liver. But no correlation was observed between acetylaspartic acid on the one hand and ammonia and urea on the other. The possible origins of acetylaspartic acid are discussed.
EFFECTS OF INTRAVENOUS INJECTIONS OF THE ANTICOAGULANT FRACTION OF INCUBATED FIBRINOGEN ON BLOOD COAGULATION
Authors: Triantaphyllopoulos D. C.
Published: October 2017

AFIF (Anticoagulant Fraction of Incubated Fibrinogen precipitated between 25 and 50% ammonium sulphate saturation) prepared from Armour's incubated bovine fibrinogen was injected in a dosage of 46–106 mg (mean: 66.5 mg) tyrosine per kilogram body weight in the external jugular vein of 10 rabbits. Blood samples were withdrawn at [Formula: see text]- or 1-hour intervals until the aspirated blood began showing signs of coagulation. The anticoagulant effect was manifested immediately and lasted for [Formula: see text] to [Formula: see text] hours in the animal. Although the blood aspirated during this time remained unclotted even after 24 hours, the surgical wound in the neck of the animal did not bleed and autopsies revealed no sign of internal haemorrhage. The bleeding time, however, was found prolonged when tested by cutting the marginal vein of the ear. The level of the coagulation factors was determined both in oxalated specimens and in specimens with no anticoagulant added. Both kinds of sample showed: (1) clottable fibrinogen content normal, thus excluding fibrinolysis as the cause of the anticoagulant effect; (2) thrombin clotting time of infinity; (3) one-stage prothrombin time longer than 60 seconds; (4) no correction of the infinite thrombin clotting time of oxalated specimens following the addition of 0.25 mg protamine per ml. This makes unlikely any appreciable release of heparin by the animal. However, oxalated and non-oxalated specimens differed in the following respects: (1) prothrombin time determined after adsorption and mixing of the eluate with adsorbed plasma was found to be normal for the oxalated blood but variably increased for the non-oxalated specimen (10–34.5 seconds); (2) the plasma precursors of plasma thromboplastin were normal in oxalated but very low in native specimens. The serum precursors of plasma thromboplastin were normal.
WATER AND ELECTROLYTE CHANGES IN AGING PROCESS WITH SPECIAL REFERENCE TO CALCIUM AND MAGNESIUM IN CARDIAC MUSCLE
Authors: Mori Kanaka , Duruisseau Jean-Paul
Published: October 2017

Concentrations of six electrolytes in seven tissues were determined in rats, the ages of which varied from 1 to 36 months, to demonstrate any changes in the electrolyte pattern during the aging process. Of the tissues studied, the electrolyte pattern of cardiac muscle showed the greatest change with age. There was a general decrease in the concentration of all cations and also of one anion, chloride, in this tissue; phosphate was the only ion to remain constant. The electrolyte pattern of the liver also changed considerably with age; the concentration of all cations decreased with the exception of calcium, which showed no variation. The electrolyte concentration of skeletal muscle changed little with age; only potassium and calcium diminished in concentration. The kidney showed an increase in the amount of calcium and phosphorus and a decrease in the level of potassium in the oldest group of animals. The aorta revealed a striking decrease in the magnesium level and a progressive increase in the amount of calcium with age. The electrolyte pattern of serum and brain was constant, except for the concentration of chloride, which was elevated in the serum of the oldest rats. The concentration of water in tissues was generally found to decrease with age.
THE DISTRIBUTION OF RADIOACTIVE PHOSPHORUS IN THE BLOOD AND TISSUES OF RABBITS TREATED WITH TAGGED ISOPROPYL METHYLPHOSPHONOFLUORIDATE (SARIN)
Authors: McPhail M. K. , Adie P. A.
Published: October 2017

By using sarin (isopropyl methylphosphonofluoridate) tagged with P32 it has been possible to determine the distribution of the P32 in the tissues after injection of sarin solutions or after cutaneous application of sarin vapor. In rabbits the percentage of P32 per gram of tissue after injection of sarin P32 was found to be higher in lung and kidneys than in other organs. The ratio of the P32 in blood to that in the body as a whole was found to decrease with the time after injection. The ratio also varied with the time after cutaneous application of vapor but in this case the results were complicated by the relatively long exposure times compared with the injection times. Cholinesterase determinations carried out on rabbit erythrocytes showed that the Cholinesterase levels dropped precipitously as the P32 concentration in the blood increased.
THE PROTECTIVE ACTION OF TOCOPHEROL AGAINST HEMOLYSIS OF RAT ERYTHROCYTES BY DIALURIC ACID
Authors: Tsen C. C. , Collier H. B.
Published: October 2017

Erythrocytes from rats on tocopherol-deficient and tocopherol-supplemented diets gave similar low values for lipid peroxides by the thiobarbituric acid test. Treatment of the cells from tocopherol-deficient rats with dialuric acid caused a marked increase in lipid peroxides and this closely paralleled the degree of hemolysis. Shaking of the red cells from tocopherol-deficient animals in an atmosphere of oxygen also resulted in a slow lipid peroxidation which again paralleled the degree of hemolysis. Addition of α-tocopherol to a suspension of erythrocytes from tocopherol-deficient rats decreased or completely prevented (depending upon concentration) hemolysis by dialuric acid and also decreased lipid peroxide formation.It is concluded that dialuric acid probably acts by catalyzing the formation of lipid peroxides in the unsaturated lipids of the membrane of erythrocytes from tocopherol-deficient animals. Tocopherol presumably inhibits peroxide formation, and therefore hemolysis, by virtue of its antioxidant action.
THE RELATIONSHIP BETWEEN THE GLUTATHIONE CONTENT OF RAT ERYTHROCYTES AND THEIR HEMOLYSIS BY VARIOUS AGENTS IN VITRO
Authors: Tsen C. C. , Collier H. B.
Published: October 2017

Erythrocytes from rats on tocopherol-deficient diets are susceptible to hemolysis by dialuric acid or by shaking in an atmosphere of oxygen, whereas the erythrocytes from rats on tocopherol-supplemented diets are relatively insusceptible. The erythrocytes from the tocopherol-deficient and tocopherol-supplemented rats initially showed identical levels of free glutathione as determined by the alloxan "305" method; treatment with dialuric acid or exposure to oxygen reduced the glutathione levels in both groups of cells, yet in no case did the extent of hemolysis parallel the decrease in glutathione.Treatment of rat erythrocytes with selenite or iodoacetate or N-ethylmaleimide decreased the glutathione content of the cells to very low levels, yet there was little hemolysis. Silver nitrate, mercuric chloride, or p-chloromercuribenzoate, on the other hand, could cause complete hemolysis with little or no decrease in the levels of erythrocyte free glutathione. There were no significant differences between the erythrocytes from tocopherol-deficient and tocopherol-supplemented animals in these experiments.It is concluded that the susceptibility to hemolysis, under our experimental conditions, is not related to the level of erythrocyte glutathione. The heavy-metal sulphydryl reagents probably cause hemolysis by a direct action upon the erythrocyte membrane.
A SIMPLE CAPACITOR TRANSDUCER FOR MEASURING BLOOD PRESSURE IN SMALL EXPERIMENTAL ANIMALS
Authors: Dowd Gerald F. , Crevier Marc
Published: October 2017

A simple capacitor transducer for measuring blood pressure in small experimental animals has been constructed. A hypodermic needle closed at its collar end by a brass diaphragm was used as the cell of the transducer. A thin plastic sheet was used as the dielectric, inserted between the diaphragm and a slightly convex brass rod serving as the other plate of the capacitor. The whole assembly constitutes a capacitor whose capacity varies inversely with the pressure as the space between the two plates changes. The transducer can be coupled directly to a conventional R. F. generator, preamplifier, and pen-writing oscillograph assembly. Results show that this simple transducer is very rugged and has a high degree of zero stability. Its sensitivity is very great, accompanied by a very small resolution time. Its accuracy is well demonstrated by the detailed recordings of the central pulse contour in normal and hydralazine-treated rats.
MARINE STEROLS: VI. STEROL BIOSYNTHESIS IN MOLLUSCS AND ECHINODERMS
Authors: Fagerlund U. H. M. , Idler D. R.
Published: October 2017

The in vivo incorporation of 2-C14-acetate into digitonin-precipitable material has been demonstrated in two molluscs, mussel (Mytilus californianus) and clam (Saxidomus giganteus). Clams are able to convert 11,14-C14-squalene into digitonin-precipitable material. When the azoylester of the material isolated from clams is chromatographed, the major portion of the radioactivity follows the least polar zone, which has previously been found to contain mainly monounsaturated Δ5-sterols.A starfish (Pisaster ochraceus) has been shown in vivo to convert ingested 4-C14-cholesterol to 7-cholestenol.
PRODUCTION OF CARBON DIOXIDE AND VOLATILE ACIDS BY MUSCLE FROM ASCARIS LUMBRICOIDES
Authors: Harpur R. P. , Waters W. R.
Published: October 2017

Under anaerobic conditions the production of carbon dioxide by chopped ascaris muscle is enhanced by the presence of carbon dioxide. This effect is not due to a lowering of the pH since raising the pH actually increases the effect. In addition to manometric measurements changes in the volatile acids were studied. Since the chromatographic procedure employed did not distinguish between isomers, the acid fractions have been designated by the number of carbon atoms contained by the acid normally eluted in each specific fraction. When minced or chopped muscle is incubated in an atmosphere of N2/CO2, 93/7, there is an increase in the C5and C4acid fractions in addition to a small but significant increase in the C2acid fraction. The ratio of C5produced to CO2evolved is 1:3. On the other hand the C3and C2acid fractions are increased under aerobic conditions.
OXIME MIXTURES AND ATROPINE IN THE PROTECTION OF MICE AND RATS FROM SARIN POISONING
Authors: Coleman I. W. , Little P. E. , Grant G. A.
Published: October 2017

The protection provided by oral administration of mixtures of oximes prophylactically in conjunction with intramuscular atropine given therapeutically against sarin poisoning in the rat and mouse is reported. N-Methylpyridinium-2-aldoxime methane sulphonate (P-2-S) in combination with diacetylmonoxime (DAM) demonstrated a synergistic action in protecting rats from sarin which raised the protection to double the value obtained from DAM alone. A similar synergism was found for P-2-S and monoisonitrosoacetone in the rat. This combination raised the protection obtainable from either partner by a factor of 8. Both oxime mixtures were less effective in the mouse than in the rat.
CHANGES IN HEPATIC ENZYME LEVELS AFTER ADRENALECTOMY: I. PHOSPHORYLASE, PHOSPHOGLUCOMUTASE, AND PHOSPHOGLUCOSEISOMERASE
Authors: Willmer J. S.
Published: October 2017

The effect of adrenalectomy upon the enzymes phosphorylase, phosphoglucomutase, and phosphoglucoseisomerase has been studied. Adrenalectomy reduces the activity of these enzymes in the liver by approximately 30%. The glucogenic steroids cortisone, hydrocortisone, and corticosterone are capable of maintaining an elevated level of phosphorylase and phosphoglucoseisomerase. The two former hormones and progesterone exert a similar effect upon phosphoglucomutase. A comparison has been made between the influence of starvation and adrenalectomy upon these enzymes. The results indicate that anorexia is not the cause of lowered enzyme levels in adrenalectomized rats.
PAPER CHROMATOGRAPHY OF COMPLEX BIOLOGICAL MATERIALS BY SOLVENT REDEVELOPMENT WITHOUT PRIOR REMOVAL OF SALTS OR PROTEINS
Authors: Pasieka Arthur E.
Published: October 2017

A solvent redeveloping technique has been devised by which amino acids, peptides, and sugars can be separated from complex mixtures in the presence of high concentrations of salts and proteins. The separations are effected by two to four successive 18-hour solvent developments with drying between each 18-hour period before subsequent staining of the chromatograms. Better separations and resolutions are obtained by such successive 18-hour solvent developments than by one continuous solvent development for an equivalent time. The effect of these redevelopments on the separations and resolutions of biological compounds is illustrated at various stages by photographs of one- and two-dimensional chromatograms. The redevelopment technique requires filter paper sheets up to 4 ft in length for one-dimensional analytical and preparative types of chromatograms.
BIOSYNTHESIS OF TWO STEROID GLYCOLS FROM 17α-HYDROXYPROGESTERONE BY SURVIVING HUMAN OVARIAN SLICES
Authors: Sandor Thomas , Lanthier André
Published: October 2017

Surviving human ovarian slices were incubated with 17α-hydroxyprogesterone in a Krebs–Ringer phosphate medium (pH 7.4), at 37 °C under an oxygen atmosphere. The substrate was partially transformed to two steroid glycols, designated as X1and X2. Chromatographic mobility studies, derivatization, and spectra in 95% ethanol and in concentrated sulphuric acid suggested that X1might be identical with Δ4-pregnene-17α,20α-diol-3-one, and X2with Δ4-pregnene-17α,20β-diol-3-one. Synthetic Δ4-pregnene-17α,20β-diol-3-one was prepared from 17α-hydroxyprogesterone. It was found identical with X2by the above-mentioned criteria.In addition to normal human ovarian tissue, slices of human Stein–Leventhal type ovaries were also incubated with the precursor and the transformation rates to X1and X2calculated for both types of tissues.Experiments were performed using as substrate Δ5-pregnene-3β-ol-20-one and progesterone in order to study the reaction with biosynthetic 17α-hydroxyprogesterone. The transformation to X1and X2seemed to follow the same course as with synthetic 17α-hydroxyprogesterone.
A MOLECULAR MECHANISM FOR ENZYMATIC DEHYDROGENATIONS INVOLVING PYRIDINE NUCLEOTIDES
Authors: Krupka Richard M. , Laidler Keith J.
Published: October 2017

The main kinetic results obtained with the dehydrogenases are briefly summarized. It is shown that the mechanism must involve a ternary enzyme–substrate–coenzyme complex, that acidic and basic groups on the enzyme surface must be involved in the reaction, and that there appears to be a transfer of the substrate from one site to another in the rate-determining step. It is suggested that this step is the actual hydrogen-transfer process. When the substrate is undergoing oxidation, this transfer is brought about by a nucleophilic attack by a basic group B−at the enzyme's active center. This attack may be on a hydroxyl hydrogen atom, and is considered to lead to the transfer of H−from the substrate to the coenzyme. The product is held to the enzyme by hydrogen bonding between the group BH (formed by the addition of a proton to the basic group B−) and the carbonyl group on the substrate.
RESPIRATORY RATE (Qo2) OF ISOLATED LIVER OF WHITE RATS EXPOSED TO SUMMER OR WINTER OUTDOOR ENVIRONMENTAL CONDITIONS
Authors: Héroux O. , Willmer J.
Published: October 2017

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NEUTRALIZATION OF COD INSULIN WITH ANTISERUM: PRECIPITATION OF INSULIN–ANTI-INSULIN COMPLEX WITH ETHANOL–WATER
Authors: Moloney P. j. , Aprile M. A.
Published: October 2017

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ISOMERIZATION OF 11-cis VITAMIN A IN VIVO
Authors: Stainer D. W. , Murray T. K. , Campbell J. A.
Published: October 2017

Single oral doses of all-trans and 11-cis vitamin A acetate were given to young, vitamin A deficient rats and the proportion of cis isomer in the intestinal tract and liver measured. Some conversion of 11-cis to all-trans occurred in the stomach and intestine, and a mixture of the two isomers was absorbed and stored in the liver. The high proportion of cis isomer found in the liver stores 5 hours after a dose of 11-cis vitamin A disappeared completely in 23 days. Oral doses of both all-trans and 11-cis vitamin A produced greater liver stores than the same doses given subcutaneously. The relative biological potency of the 11-cis isomer was the same by either route, which indicated that the low potency of this isomer was not due only to poor absorption from the intestine.
THE ACTIVATION OF VARIOUS TYPES OF UTERINE MUSCLE DURING STRETCH-INDUCED CONTRACTION
Authors: Daniel Edwin E.
Published: October 2017

The electrical and mechanical activity of uterine strips from human beings, cats, rats, and rabbits was studied using glass pore surface electrodes and isometric recording of tension. Uterine strips from animals treated with estrogen, or with estrogen and progesterone, were compared with those from pregnant animals. Marked differences in both electrical and mechanical activity were found among the various strips studied. Strips from estrogen or pregnant cats were activated primarily by propagated "ail-or-none" action potentials. Propagated action potentials were recorded from rat uterine strips of all types, but they originated from several sites during the same burst, and did not spread over the entire uterus or even a few millimeters in some strips. Mechanical strain appeared to play a role in activation in rat uterus. In strips from uteri of nonpregnant rabbits, action potentials were small, and propagation was slow and limited in extent. Action potential conduction played a minor role in activation in these tissues. Uterine strips from pregnant rabbits resembled those from cats and rats. Action potentials similar to those of animal uteri were recorded from strips of pregnant human uterus. Progesterone pretreatment and pregnancy increased the number of action potentials and duration of contraction. Progesterone pretreatment reduced the sensitivity of cat uterus to stretch. The effect of reduction of external sodium concentration on propagation of uterine action potentials was studied. The results are discussed in relation to the mechanisms underlying electrical activity and to the question of whether electrical activity is a determinant of mechanical activity in the uterus.
MODIFICATIONS OF THE ASSAY FOR SMALL AMOUNTS OF ANTIDIURETIC HORMONE
Authors: Gordon Ellen R. , Kalant H.
Published: October 2017

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A COMPARISON OF THE EFFECTIVENESS OF INTRAVENOUS, AS OPPOSED TO SUBCUTANEOUS, INJECTION OF PROGESTERONE FOR THE INDUCTION OF ESTROUS BEHAVIOR IN THE RAT
Authors: Lisk R. D.
Published: October 2017

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CHANGES IN HEPATIC ENZYME LEVELS AFTER ADRENALECTOMY: II GLUCOSE-6-PHOSPHATASE, GLUCOSE-6-PHOSPHATE DEHYDROGENASE, AND 6-PHOSPHOGLUCONATE DEHYDROGENASE
Authors: Willmer J. S.
Published: October 2017

Adrenalectomy caused a decrease in the hepatic levels of glucose-6-phosphatase and glucose-6-phosphate dehydrogenase. Restoration to normal levels in rats which had been fasted for 18 hours was obtained by treatment with cortisone or corticosterone. In fed animals hydrocortisone and progesterone were also capable of maintaining an elevated level of glucose-6-phosphatase. Cortisone and corticosterone raised the level of this enzyme in fed sham-operated animals, but none of the other steroids showed this effect. The activity of 6-phos-phogluconate dehydrogenase did not change significantly under the influence of adrenalectomy or individual steroid hormones.A comparison is made between the effects of adrenalectomy and starvation upon the level of these enzymes in the liver during a 7-day period.
CATALASE LEVELS AND RADIOSENSITIVITY OF LIVER CELLS
Authors: Myers D. K.
Published: October 2017

Following exposure of regenerating liver to 580 r X radiation at a time when the average amount of DNA per cell nucleus has reached 1.6 times the normal value, the usual increase in number of cell nuclei was retarded while the average amount of DNA per cell nucleus continued to rise until it approached twice the normal value. Cell division was delayed for an unusually long period following irradiation at this stage of development. On the other hand, there was no corresponding increase during liver regeneration in the effects of high doses of X radiation on diphosphopyridine nucleotide concentrations in the liver. Although the liver catalase concentration decreased during liver regeneration, inhibition of catalase activity failed to increase the radiosensitivity of liver cells.
COMPOSITION OF EPIPHYSEAL CARTILAGE: II. DIFFERENCES IN COMPOSITION OF EPIPHYSEAL AND ARTICULAR CARTILAGE OF RACHITIC CHICKS
Authors: Cipera J. D.
Published: October 2017

The results of comparative analyses of epiphyseal and articular cartilages from the tibiae of rachitic chicks indicate a relationship between the amounts of mucopolysaccharides and of mineral constituents of these tissues, as evidenced by significantly close epiphyseal/articular ratios of hexosamine, uronic acids, and ash values. While the amount of collagen appears to be higher in articular cartilage, the amounts of mucopolysaccharide constituents, hexosamines and uronic acids, and of ash are greater in the epiphyseal cartilage.
THE LIPID COMPOSITION OF BACILLUS CEREUS AS INFLUENCED BY THE PRESENCE OF ALCOHOLS IN THE CULTURE MEDIUM
Authors: Kates M. , Kushner D. J. , James A. T.
Published: October 2017

Cells of Bacillus cereus grown in an alcohol-free medium (control cells) had a lipid content of 2.6 ± 0.4%, on a dry weight basis. About half of the lipids consisted of phosphatides, including phosphatidyl ethanolamine (40%), phosphatidyl glycerol (28%), lecithin (6%), lyso compounds (10%), and three acidic phosphatides of unknown structure. The fatty acids of the total lipids were predominantly saturated, the major components being branched-chain C13, C15, and C17acids. The neutral lipids consisted mostly of diglycerides, with a small amount of triglycerides. Five to ten per cent of the lipids was obtained as unsaponifiable material, consisting chiefly of long-chain (n-C16and n-C18) alcohols, and having traces of long-chain aldehydes (derived from plasmalogens).Cells grown in the presence of alcohols usually had a higher phosphatide content, a correspondingly lower non-phosphatide content, and a higher non-saponifiable content than control cells. Total lipid content or relative proportions of the phosphatide components in alcohol-grown cells did not differ significantly from those of control cells.
RENAL CLEARANCE OF SODIUM AND POTASSIUM IN HYPOTHERMIA
Authors: Kanter G. S.
Published: October 2017

The handling of sodium and potassium by the renal tubules at various levels of hypothermia was studied. Fourteen dogs were anesthetized with 30 mg/kg sodium pentobarbital. After suitable control clearance measurements, the rectal temperature was lowered progressively by ice-packing to about 25 °C while renal clearances were continuously measured. Artificial respiration was not used. No change in plasma sodium was detected but plasma potassium fell significantly from a control value of 4.1 ± 0.09 meq/1. at 38 °C to 3.4 ± 0.12 meq/1. at 25 °C. Urine sodium concentration fell during exposure to cold while potassium concentration increased slightly. In spite of the marked fall in glomerular nitration rate (69.0 ± 3.1 ml/minute control to 17.0 ± 3.6 ml/minute at 25 °C) the final urine flow at 25 °C was slightly greater than that of control. The clearance ratios (in percentage) increased significantly, reflecting the marked decrease in tubular reabsorption: water, 0.49 ± 0.05 at 38 °C to 2.02 ± 0.25 at 25 °C; sodium, 0.47 ± 0.12 to 1.13 ± 0.27; potassium, 18.0 ± 2.6 to 54.0 ± 12.0. The difference in clearance ratio alterations is a reflection of the dissimilar effect of hypothermia on particular renal regulations.
A CHROMATOGRAPHIC STUDY OF SOME CONVERSION PRODUCTS OF ESTRONE-16-C14IN THE URINE AND FECES OF THE LAYING HEN
Authors: Ainsworth L. , Carter A. L. , Common R. H.
Published: October 2017

Estrone-16-C14was administered intravenously to a laying hen. The urine excreted during the succeeding 24 hours contained, on the basis of chromatographic evidence, the following radioactive conversion products of estrone: estriol, 16-epiestriol, 17-epiestriol, 16-oxoestradiol-17 β, estradiol-17 β, and 16-oxoestrone. Three other minor conversion products were not identified. 16-Oxoestradiol and 16-oxoestrone were characterized more fully by chromatographic examination of their sodium borohydride reduction products.In a second experiment, urine and feces excreted during the first two 24-hour periods after administration of estrone-16-C14were examined separately for radioactive conversion products. Of the radioactivity injected, 24.5% was recovered in the estrogen-containing extracts of the excreta. The urinary extracts contained 69% of the recovered radioactivity and the fecal extracts contained 31%.In a third experiment, recoveries of urinary metabolites after enzymatic and after acidic hydrolysis were compared. The recovery after acidic hydrolysis was approximately two-thirds of that recovered after enzymatic hydrolysis. Most of this loss could be accounted for by destruction of 16-oxoestrone and a minor unidentified metabolite during acidic hydrolysis. The distribution of the conversion products on the urinary chromatogram confirmed the results of the previous experiments.None of the experiments gave any evidence for the presence of 2-methoxyestrone, estradiol-170α, equilin, or equilenin.
THE CONSTRUCTION OF AN ULTRAFILTRATION UNIT TO MEASURE THE BINDING OF CERTAIN NITROGEN MUSTARDS TO SERUM PROTEIN
Authors: Linford J. H. , Legal J. , Zacharias E.
Published: October 2017

An ultrafiltration unit has been designed, and constructed to contain a 10-ml volume. The unit is leakproof, is self-contained, and can be operated inside a small refrigerator or oven. It has been used with "Visking" cellulose acetate membrane to separate the colloidal protein phase of human blood serum from the aqueous dispersing phase, and to study the distribution of certain nitrogen mustards between these phases. The results indicate that these drugs are adsorbed to the protein to a high degree and that the presence of the benzene rings in the nitrogen mustards is mainly responsible for this adsorption.
THE PRESENCE IN NORMAL HUMAN URINE OF A SUBSTANCE OR SUBSTANCES ANTAGONIZING HISTAMINE, 5-HYDROXYTRYPTAMINE, AND ACETYLCHOLINE (PRELIMINARY REPORT)
Authors: Kovacs B. A. , Melville K. I.
Published: October 2017

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THE INCORPORATION OF TRYPTOPHAN ANALOGUES INTO RAT PLASMA PROTEINS
Authors: Berecz Anita , Godin C.
Published: October 2017

When 7-azatryptophan and 5-methyltryptophan are fed to protein-depleted rats, the animals lose weight more rapidly than control rats. Protein-depleted rats fed a diet containing tryptophan gain weight. 7-Azatryptophan is incorporated in vivo into rat plasma proteins, whereas 5-methyltryptophan is not incorporated.
BLOOD PRESSURE BEFORE, DURING, AND AFTER OVIPOSITION IN THE HEN
Authors: Hunsaker W. G. , Sturkie P. D.
Published: October 2017

The central arterial pressure was recorded continuously in eight hens before, during, and after oviposition. Blood pressure remained relatively stable for the 2-hour period prior to oviposition. Approximately 30 seconds prior to oviposition, there was a marked change in the pressure pattern. While there was no marked increase in the maximum level of systolic pressure or decrease in the minimum level of the diastolic pressure, there were large fluctuations within this range. Immediately after oviposition there was a decrease in pressure in seven of the eight birds studied. The average decrease in systolic pressure was 17.6 mm Hg and in diastolic pressure 7.6 mm Hg. There were indications of an increase in pressure within about 15 minutes after oviposition.
PHOSPHORYLATION OF DIGLYCERIDES BY RAT BRAIN
Authors: Strickland K. P.
Published: October 2017

The addition of D-α,β-dimyristin was observed to stimulate by three to six times the labelling of phospholipids from radioactive inorganic phosphate (Pi32) by glycolysing homogenates and respiring mitochondria of rat brain. The increase in labelling was confined to the glycerophosphate (GP) isolated by two-dimensional chromatography from the water-soluble hydrolysis products obtained on weak alkaline treatment of the labelled phospholipids. The GP formed under these conditions is presumed to be derived mainly from phosphatidic acid formed by the phosphorylation of the diglyceride. A similar effect was observed for D-α,β-dipalmitin, D-α,β-diolein, and natural diglycerides prepared from either egg lecithin or spinal cord lecithin, but not for D-α-β-distearin. L-α,β-Diolein was much less effective than the D-isomer, suggesting a stereospecificity on the part of the enzymic phosphorylation of diglyceride. Experiments on the effects of the omission of Mg++and the addition of glycolytic inhibitors on the stimulation of the labelling from Pi32caused by D-α,β-dimyristin and D-α,β-diolein in the anaerobic homogenate system suggested that the increased phosphorylation caused by added diglycerides was closely coupled to active glycolysis. A comparison of the relative specific activity of the lipid P, following incubation of Pi32and ATP32in the anaerobic homogenate system inhibited by fluoride with and without D-α,β-diolein added, showed that the phosphate of the newly formed phosphatidic acid was derived from ATP, suggesting the presence of a D-α,β-diglyceride kinase.
STUDIES ON THE IN VITRO PRODUCTION OF CORTICOSTEROIDS BY ADRENAL GLANDS FROM NORMOTENSIVE INDIVIDUALS AND HYPERTENSIVE PATIENTS
Authors: Davignon Jean , Koiw Erich , Nowaczynski Wojciech , Tremblay Gilles , Genest Jacques
Published: October 2017

The production of aldosterone and other corticosteroids by adrenal glands surgically removed from 5 normotensive subjects with renal disease of various types, 11 patients with arterial hypertension, and 2 with Cushing's syndrome was investigated in vitro by the incubation chromatographic technique. The rate of steroid formation per unit weight of tissue was markedly lower in severe and malignant hypertension and slightly higher in benign hypertension as compared with the rate in normotensive controls. The amount of steroid released varied widely from one gland to the other and showed marked overlapping between the various groups; these variations were most prominent in benign hypertension, less in the normotensive group, and least evident in severe and malignant hypertension. The response of steroidogenesis to ACTH stimulation in vitro was slightly reduced in severe and malignant hypertension. The mean output of aldosterone by adrenal glands from hypertensives was slightly above the mean value obtained with normotensive control glands. The percentage of aldosterone formation in respect to total steroid production was roughly correlated with the severity of hypertension. In four hyperplastic adrenals obtained from two cases of Cushing's syndrome, the in vitro formation of steroids per unit weight of tissue and the response to ACTH did not differ significantly from that found in glands obtained from the other patients under study. The value of in vitro studies for the assessment of the functional capacity of the adrenal cortex is discussed.
THE DISSOCIATION OF α- AND β-LIPOVITELLIN IN AQUEOUS SOLUTION: PART I. EFFECT OF pH, TEMPERATURE, AND OTHER FACTORS
Authors: Burley R. W. , Cook W. H.
Published: October 2017

The effect of pH, temperature, ionic strength, and lipoprotein concentration on the reversible dissociation of α- and β-lipovitellin in aqueous solutions above pH 6 has been examined by ultracentrifugal measurements. Under otherwise similar conditions α- and β-lipovitellin are 50% dissociated at pH 10.5 and 7.8, respectively. Both lipovitellins undergo an irreversible aggregation above about pH 11; β-lipovitellin is sometimes converted to a non-dissociable form upon aging. Dissociation of both lipovitellins decreases with increasing ionic strength and increasing temperature. Although the ultracentrifugal method has limitations, provisional equilibrium constants and thermodynamic data were obtained from it that are comparable with those obtained for certain protein systems.
THE DISSOCIATION OF α- AND β-LIPOVITELLIN IN AQUEOUS SOLUTION: PART II. INFLUENCE OF PROTEIN PHOSPHATE GROUPS, SULPHYDRYL GROUPS, AND RELATED FACTORS
Authors: Burley R. W. , Cook W. H.
Published: October 2017

Removal of protein phosphate groups from α- and β-lipovitellin by means of a phosphatase has shown that these groups do not take part in the dissociation–association process. They appear, however, to be responsible for a difference in their ease of complex formation with calcium ions, and also for their different chromatographic behavior on columns of hydroxyapatite.Both lipovitellins contain about 26 μmoles/g of sulphydryl groups. Sulphydryl group reagents had no effect on the dissociation of α-lipovitellin but markedly changed the behavior of β-lipovitellin. N-Ethylmaleimide and p-chloromercuribenzoate displaced the equilibrium towards the associated form at all pH values below pH 10, but iodoacetamide tended to stabilize the dissociated form against pH changes. The different behavior of these reagents indicates that the sulphydryl groups are not directly involved in the dissociation but their substitution probably causes other changes in β-lipovitellin that affect its dissociation.
DETERMINATION OF GLUTAMINE AND GLUTAMIC ACID IN THE BLOOD PLASMA OF CHICKS BY A COMBINED CHROMATOGRAPHIC AND MICROBIOLOGICAL METHOD
Authors: Olsen Ellen M. , Hill D. C. , Branion H. D.
Published: October 2017

Glutamine was separated from glutamic acid by chromatographing deproteinized plasma on a 10-cm column of Dowex 1X8 and by eluting with acetate buffer, pH 4.2. The first portion of eluate, which contained the glutamine but no glutamic acid, was subjected to microbiological assay using Lactobacillus plantarum as a test organism. Recovery of glutamine added to plasma was satisfactory and the precision of the assays conducted was within 4%. Several substances were found to interfere with the microbiological assay but these were eliminated by the chromatographic procedure. The method was extended to the determination of glutamic acid by continued elution of the column with acetate buffer, pH 4.2, fractionation of the eluate, and determination with ninhydrin. Average glutamine and glutamic acid contents of plasma of normal non-fasting chickens were 12.8 and 3.4 mg per 100 ml respectively.
STUDIES ON THE NUMBER AND VOLUME OF FAT CELLS IN ADIPOSE TISSUE
Authors: Zingg W. , Angel A. , Steinberg M. D.
Published: October 2017

The changes in number and volume of fat cells accompanying changes in the size of the perirenal fat depots of rats induced by dietary and other means have been investigated by direct histological examination and by estimation of the total desoxyribonucleic acid (DNA) and fat content. With both methods, an increase in cell volume and in cell number was found to accompany an increase in depot volume.