bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation and Binding of Histamine by Rat Tissues In Vitro
Authors: Schayer Richard W.
Published: December 2017

Several rat tissues decarboxylate C14 l-histidine and bind the resulting histamine in stable form. The pyloric portion of the stomach is by far the most active. Pretreatment of the rats with cortisone appears to reduce the histamine-binding activity of most tissues while prior adrenalectomy increases it. The stomach is the exception; here the reverse is true. Using rat lung as a test tissue, it was found that prednisone, prednisolone and 9-α-fluorohydrocortisone appear to be more active than cortisone or hydrocortisone in inhibition of histame bininding. The mechanism of this reduction of histamine-binding activity of rat lung involves the loss of extractable histidine decarboxylase activity.
Succinoxidase and Gastric Acid Secretion
Authors: Davenport Horace W. , Chavré Virginia J.
Published: December 2017

The participation of succinoxidase in gastric acid secretion and in renal transport of p-aminohippurate (PAH) was studied in mice and frogs using antimycin A and sodium malonate as inhibitors. Antimycin A inhibits both gastric acid secretion and renal PAH accumulation in both species in vitro, but when given intraperitoneally it inhibits acid secretion and PAH accumulation in the frog but neither function in the mouse. Malonate given subcutaneously inhibits renal PAH accumulation in both species but has no effect on gastric acid secretion. The effect of antimycin A is interpreted in terms of inhibition of electron transport systems essential for acid secretion, and the failure of malonate to affect acid secretion is not taken to be conclusive evidence of the absence of participation of succinic dehydrogenase.
Comparison of Enzyme Distribution in Liver of Normal, Fasted and Hypoxic Guinea Pigs
Authors: Klein Peter D. , Thomson John F.
Published: December 2017

Intermittent hypoxia (16 hr/day for 3 days) resulted in decreases in the succinic dehydrogenase, uricase and catalase activities of guinea pig liver. In the controls fasted to duplicate the weight loss of the hypoxic group, decreases in uricase and catalase but not in succinic dehydrogenase were seen when the activities were expressed on a wet weight basis. Decreases in the enzyme activities per unit nitrogen in fasted animals are attributable to enzyme inactivation with subsequent accumulation of nonenzymatic nitrogen which diluted the existing enzymatic protein. In the hypoxic animals, there was a true loss of liver protein nitrogen. No differences in sedimentation characteristics were found for the particles containing succinic dehydrogenase activity in the normal, fasted or hypoxic livers. Uricase, in the hypoxic liver alone, showed a greatly increased sedimentability, apparently as a result of a change in the physical state of the uricase-containing particles.
Relationship Between Ambient Temperature and the Spontaneous Running Activity of Normal and Hypertensive Rats
Authors: Fregly Melvin J.
Published: December 2017

When daily illumination is held constant, lowering ambient temperature increases spontaneous running activity of both normal and hypertensive rats in a sigmoid fashion. The spontaneous activities of normal and hypertensive rats were similar in the range of ambient temperatures from 25–30°C. At all temperatures lower than 25°C, viz. 20, 15 and 10°C, the activity of normal rats was significantly higher than that of hypertensive rats. Hence, hypertension appeared to limit the increased running activity normally observed in cold air.
Heart Rate During Short Periods of Apnea in Curarized Dogs
Authors: Nahas Gabriel G.
Published: December 2017

Under light Pentothal anesthesia, 11 dogs were fitted with catheters in the right atrium and femoral artery. An electrocardiogram was taken in the standard leads. Arrest of ventilation was induced by intravenous injection of d-tubocurarine and mechanical breathing installed. Photokymographic records of heart rate, right atrial pressure and femoral artery pressure were taken during mechanical ventilation and at the end of a 90-second period of ‘apneic oxygenation’ which is a period of arrest of ventilation following partial denitrogenation of the animal. Arterial blood samples were collected before, during and after the apneic period for measurement of ph and samples of end expiratory air were withdrawn for measurement of pCO2. A significant bradycardia was noticeable after 60 seconds of ‘apneic oxygenation;’ after 90 seconds it amounted to a 7% fall of the control heart rate which averaged 148/min. This bradycardia was accompanied by a significant rise in systemic pressure averaging 5.6 mm Hg, and a significant fall in central venous pressure averaging 2.1 mm Hg. During the same time end expiratory pCO2 increased by 16 mm Hg and blood arterial ph dropped by 0.02. Similar changes were observed after bilateral cervical vagotomy, and when apnea was associated with moderate hypoxia. These results indicate that respiratory acidosis is the main factor responsible for the bradycardia of apnea observed under the present experimental conditions.
Transmembrane Potentials and Contractility in the Pregnant Rat Uterus
Authors: West Theodore C. , Landa Jorge
Published: December 2017

Surviving segments from the uteri of pregnant Long-Evans rats were studied. The rats were within 12 hours prepartum. Spontaneous contractility was measured by use of a strain gauge transducer. By means of the microelectrode technique of intracellular recording, transmembrane potentials were observed simultaneously. It was observed that trains of transmembrane action potentials appeared during rhythmic contraction. The frequency was low at the onset, increased to a maximum averaging greater than one per second and then diminished before cessation of firing. The average duration of impulse trains was 35 seconds at 30°C, less than the duration of the total contraction. Slow depolarization between action potentials often appeared after the first several cycles in a train of impulses. This phenomenon resembled the cardiac pacemaker prepotential. In light of similar experimental observations on stretch receptors by other investigators, it was considered possible that interfiber spread of excitation in uterus might be mediated by stretch.
Effect of Estrogen on Thyroidal and Renal Clearance of I131 in the Rat
Authors: Feldman Joseph D.
Published: December 2017

The administration of estrogen for 3 days to castrate and hypophysectomized rats markedly increased thyroidal clearance. The administration of estrogen for 15 and 30 days doubled thyroidal clearance in hypophysectomized rats but was without effect in castrate rats. Renal clearance was slightly decreased by the injection of estrogen. I131 space and serum I131 levels were not significantly influenced by estrogen. A direct action of estrogen on the thyroid is indicated.
Succinic and Malic Oxidase in Gastric Hydrochloric Acid Production
Authors: Vitale Joseph J. , Jankelson Oscar M. , Connors Patricia , Hegsted D. Mark , Zamcheck Norman
Published: December 2017

Effect of histamine on the activity of succinic oxidase and malic dehydrogenase was studied in guinea pig and human gastric mucosa. Human tissue was obtained through the surgical services of the Boston City Hospital. Control value for the succinic oxidase system of the proximal half of the guinea pig stomach was approximately 480 ( Qo2 (N) (µl O2/mg nitrogen/hr.)). After histamine, this value rose to 550 in 30 minutes with a simultaneous rise in titratable acidity of the stomach contents. Animals fasted for 72 hours had a Qo2 (N) of approximately 500 and after histamine a Qo2 (N) of 700 was observed. Spectrophotometric analysis of succinic dehydrogenase and cytochrome oxidase activities, two of the major components of the succinic oxidase system, revealed that both components are increased following histamine administration. Malic dehydrogenase, however, was not affected by histamine treatment. Succinic dehydrogenase was demonstrated by histochemical localization and was concentrated below the superficial mucous layer where parietal cells were abundant. Succinic oxidase activity of human gastric mucosa was demonstrable only in those specimens containing abundant parietal cells. This study confirms the view that HCl production by parietal cells is associated with aerobic metabolism and is perhaps under enzymatic control. The study suggests that the succinic oxidase system may be involved in the production or secretion of HCl.
Effect of Complete Portalization of the Renal Effluent Blood on Arterial Pressure
Authors: Maluf N. S. R.
Published: December 2017

Evidence has accumulated that the kidneys release a substance which tends to prevent arterial hypertension. This study was to find principally whether complete portalization of the renal effluent blood results in hypertension and thus point to an antipressor agent inactivated by the liver. Chronic complete portalization of the renal effluent blood of dogs did not alter arterial pressure. Furthermore, such portalization did not prevent onset of hypertension after renal arterial constriction with clamps.
Distribution of Fluid and Electrolytes and Concentration of Actomyocin and Other Proteins in the Myocardium of Dogs With Chronic Congestive Heart Failure
Authors: Benson Ellis S. , Freier Esther Fay , Hallaway Ben E. , Johnson Marlene J.
Published: December 2017

In 17 dogs with chronic heart failure due to surgically produced pulmonary stenosis and tricuspid insufficiency and 13 control dogs, myocardial concentrations of water, potassium, sodium, chloride, calcium, magnesium, total and alkaline soluble protein, actomyosin, myoglobin and collagen were measured. In 11 of the dogs with heart failure and in 7 control dogs, psoas muscle was also analyzed and in these dogs intracellular and interstitial concentrations of water and electrolytes were calculated by assuming a restricted distribution of chloride. In the dogs with heart failure the following were noted: a 20–33% increase in myocardial and psoas interstitial fluid mass; a slight increase in intracellular sodium concentration but essentially no change in the intracellular concentrations of other electrolytes or of water; decreased myocardial concentration of actomyosin per unit of fat-free solids as judged by the viscosity response of extracted actomyosin to the addition of adenosinetriphosphate; no change in the concentration of actomyosin in psoas muscle. Ratios of intracellular magnesium to actomyosin and of the sum of intracellular sodium and potassium to actomyosin were increased to a variable extent in the myocardium in heart failure.
Effects of Low-Level X-Irradiation on Oxygen Consumption of Bullfrog Erythrocytes
Authors: Martin W. S. , Grubbs R. C. , Lessler M. A.
Published: December 2017

The respiration of nucleated erythrocytes from bullfrogs ( Rana catesbiana) was determined following exposure to either 25 r or 60 r x-irradiation. Using the Warburg technique, the rate of oxygen consumption of 50% cell suspensions was studied at either 25°C or 30°C. A decrease of 5°C in the incubation temperature produced a marked decrease (approximately 20%) in oxygen consumption of both nonirradiated and irradiated erythrocytes. There was a 10–15% inhibition in oxygen consumption at an incubation temperature of 30°C following both 25 r and 60 r. At 25° there was a 14% depression following 60 r but no significant change after 25 r. The radiation effect was modified by both time and temperature factors indicating that these factors are related to the expression, rather than to the extent, of radiation injury. Consistent correlations between dose and radiation effect have been established.
Osmotic (Mannitol) Diuresis in the Anesthetized Rat Effectiveness of Water Conserving Mechanisms
Authors: Corcoran A. C. , del Greco F. , Masson G. M. C.
Published: December 2017

During mannitol osmotic diuresis, the rat shows a dependence of urine flow on solute load and a rough proportion between solute load and electrolyte output. In terms of body weight, the rat's renal ability for water conservation during osmotic diuresis is to that of dog and man, respectively, as 6 is to 2.5 and to 1; this ability to conserve water may be a factor in the survival capacity of this species. Mercurial diuresis in the rat, as in other species, is apparently an osmotic diuresis. The procedure permits partial characterization of the mechanisms of action of test materials with renal and urinary effects.
Increase in Serum Ribonuclease Activity After Bilateral Nephrectomy
Authors: Rabinovitch M. , Dohi S. R.
Published: December 2017

Serum ribonuclease activity increased after bilateral nephrectomy or hydronephrosis in the rat. This increase could be shown to occur 40 minutes after bilateral nephrectomy and was not abolished by either simultaneous adrenalectomy, pancreatectomy, evisceration or cortisone administration in single or repeated doses. As a similar enzyme was found in the urine, it is suggested that the increased serum activity is due to nonexcretion by the kidneys. The results also indicate that the increased activity did not originate from the digestive tract, pancreas or lymphoid tissues, and that stress did not play a major role in the phenomenon.
Effect of Localized Brain Stem Lesions and Supradiaphragmatic Vagotomy on X-Irradiation Emesis in the Monkey
Authors: Brizzee Kenneth R.
Published: December 2017

Bilateral ablation of area postrema by thermal coagulation resulted in loss of the normal early emetic response to total body x-irradiation in three monkeys ( Macaca irus). Similar lesions in the lower descending vestibular nucleus with some damage to area postrema eliminated the vomiting reaction in one animal, but failed to do so in two others. Bilateral lesions in the dorsal sensory vagal nucleus without involvement of area postrema or other structures failed to inhibit vomiting to the standard dose of x-irradiation. In two other animals with similar lesions, but with extensive damage to area postrema or the nucleus of the tractus solitarius on one side, no vomiting occurred. Two animals with bilateral lesions in the superficial (ventricular) portion of the hypoglossal nuclei vomited during x-irradiation or in the usual interval following radiation. Supradiaphragmatic vagotomy resulted in complete inhibition of vomiting in five animals.
Alteration in Mammalian Nerve Metabolism by Soluble and Gaseous Anesthetics
Authors: Carpenter F. G.
Published: December 2017

A variety of anesthetics (chloretone, phenobarbital, cyclopropane, nitrous oxide and xenon) in sufficient quantities will reversibly abolish excitation and conduction in isolated rat sciatic nerve. Under these conditions, in parallel experiments certain aspects of the resting respiration (O2 consumption) and carbohydrate metabolism (pyruvate utilization) of mammalian nerve have been measured. The rate of O2 uptake in resting nerve may be significantly diminished by at least four of these agents under conditions which do not alter excitation and conduction. Blockade concentrations or partial pressures were found to inhibit the resting respiration of nerve from 50–85%. Pyruvate utilization by nerve was not always diminished by anesthetics in a manner parallel to the alteration in the resting respiration. An equivalent depression of electrical activity produced in nerve by each substance was by no means accompanied by the same pattern of alteration in nerve metabolism. These results are similar to those of Larrabee and Edwards (1955) obtained with rat autonomic ganglia although quite different anesthetic agents were employed.
Urinary Recovery of 3-Methylglucose Administered to Rats
Authors: Csáky T. Z. , Glenn J. E.
Published: December 2017

The fate of 3-methylglucose in rats was studied in view of previous findings that this sugar is actively absorbed from the intestine. Unchanged 3-methylglucose was identified in the urine following the administration of the sugar. The recovery is essentially quantitative provided that bacterial growth is inhibited during collection. E. coli can utilize 3-methylglucose as sole source of carbon.
Hematocrit and Erythrocyte Volume Determinations in the Goat as Related to Spleen Behavior
Authors: Anderson Rubert S. , Rogers Earl B.
Published: December 2017

Studies on the blood and circulation in the goat show that they possess some features which, while common to other species, are present in the goat to an exaggerated degree. The fraction of plasma retained among the erythrocytes in hematocrit determinations made in the usual manner was much larger than in other species. The percentage increase in the hematocrit immediately following intravenous injections of adrenaline was larger in some animals than reported values for dog and man. The concentration of erythrocytes in the venous blood of goats was frequently variable even in the same animal under different experimental conditions. The time-concentration curves obtained during erythrocyte volume determinations by means of Cr51-labeled cells were often anomalous and suggested that mixing of the labeled cells with total body cells was slow under some circumstances. This was confirmed by determinations associated with adrenaline injections. Also, experiments in which counts were determined in the splenic region of an intact animal following injections of Cr51-labeled cells showed slow accumulation. The spleen was found to be quantitatively responsible for most of the adrenaline response since the effect was very small in splenectomized animals. It is probable that the spleen is also responsible for much of the slow mixing of labeled cells and the variability of the hematocrit.
Changes in Electrical Activity of the Medulla on the Intravenous Injection of Hypertonic Solutions
Authors: Clemente Carmine D. , Sutin Jerome , Silverstone J. Trevor
Published: December 2017

Electric recording with insulated steel electrodes in the dorsal part of the medulla of the cat has revealed an area which responds to changes in the tonicity of the blood stream. Hypertonic saline solutions injected intravenously resulted in a response characterized by increased electrical activity in the floor of the fourth ventricle at the level of the obex. The region involved is in juxtaposition to the area postrema overlying the vagal nuclei and may represent a central site of osmoreception.
Localized Response in the Posterior Hypothalamus Following Intravenous Administration of Pitressin
Authors: Sutin Jerome , Clemente Carmine D.
Published: December 2017

Electrical recording experiments performed on adult cats have revealed an area in the hypothalamus, lateral and slightly rostral to the mammillary bodies, which responds characteristically to intravenous injections of Pitressin. Spike activity at a frequency of 4–10/sec. was observed in this area and generally started 4–8 minutes after the injection of 1 or 2 pressor units of Pitressin. The electrical discharge was observed to last for periods of up to 35 minutes and commenced well after the blood pressure response returned to normal. Epinephrine and other vasopressor drugs did not elicit the hypothalamic response observed with Pitressin.
Differential Permeability of the Rabbit Placenta to Various Sugars
Authors: Davies J.
Published: December 2017

The permeability of the rabbit placenta at term has been studied by following maternal and fetal blood sugar curves during a controlled intravenous infusion of the following sugars: disaccharides (sucrose, lactose, maltose); hexoses (glucose, mannose, galactose, sorbose, fructose); pentoses (arabinose, xylose, ketoxylose) and the trisaccharides dihydroxyacetone and glyceraldehyde. The disaccharides were almost completely blocked by the placenta. Among the hexoses, and possibly among the pentoses, there was a clear differential permeability on the part of the placenta to the aldo-sugars on the one hand and the keto-sugars on the other. Results with the trisaccharides were inconclusive. The results were held to furnish added proof for the complex character of the placental transfer mechanism for sugars. No evidence was put forward for the possible mechanism involved.
Role of the Thyroid in Metabolic Response to Low Temperature
Authors: Hsieh A. C. L. , Carlson L. D.
Published: December 2017

Cold-adapted rats, kept at 5°C, and warm-adapted rats, kept at 28°C, were curarized and oxygen consumption; heart rate; muscular activity; rectal, foot and room temperatures recorded during a period at 30°C and during exposure to cold. The experiments were performed before and at varying intervals after thyroidectomy. Oxygen consumption measured at 30°C reached a minimum 8 days after thyroidectomy in the rats kept at 5°C and 12 days after thyroidectomy in the rats kept at 28°C. The half-time for the decline was twice as long for the rats kept at 28°C, indicating that thyroxin stores were being utilized twice as fast by the rats kept at 5°C. Upon exposure to cold the rats responded by an increase in oxygen consumption. Since the response persisted after thyroxin stores had been depleted it is concluded that the metabolic response to cold is not directly dependent upon the amount of circulating thyroxin. Rats kept at 5°C reduced their food intake and lost weight following thyroidectomy, but maintained a high metabolic rate. The significance of these findings are discussed.
Comparison of the Absorption and Destruction of the Lactone and Salt Form of Glucuronic Acid by Dogs
Authors: Buckeridge F. A. , Freeman Smith
Published: December 2017

Comparative studies were made on the fate of d-glucuronolactone and d-glucuronate in dogs. The studies included: a) measurement of the rate of conversion of the lactone into the salt form at various ph values ranging from 2.0 to 7.4; b) measure of the rate of absorption from isolated loops of small intestine; c) determination of the blood plasma concentration in relation to intestinal absorption of the two forms of glucuronic acid in normal, Eck fistula and nephrectomized animals; d) the stability and magnitude of the plasma values were determined following the intravenous injection of the lactone or salt form of glucuronic acid into nephrectomized dogs. From the foregoing studies, it was determined that: a) glucuronolactone is rapidly converted into glucuronate at the ph of plasma; b) glucuronolactone is absorbed from the small intestine much more rapidly than is glucuronate; c) absorbed glucuronolactone is metabolized rapidly while glucuronate appears to be relatively inert in the body and to occupy a space similar to that of inulin. The limiting factor in the metabolism of glucuronolactone is the rate of its conversion into the salt form.
Impairment of Triglyceride Absorption by the Exclusion of Pancreatic Juice in the Rat
Authors: Karvinen Esko , Lin T. M. , Ivy A. C.
Published: December 2017

A fat balance study was conducted on 12 rats with and 12 without exclusion of the pancreatic juice, using tripalmitin, trielaidin, triolein, tallow and corn oil, or fats varying in regard to melting point, saturation, and cis and trans isomerism. Exclusion of pancreatic juice decreased the utilization of these fats. The decrement ranged from 14 to 18% of the intake of the different fats when fed at a level of 8% of the dry weight of the diet. The extent of impairment expressed as millimols could not be correlated with the physical and chemical characteristics of the fats; but if expressed as percentage of fat absorbed, the impairment was related to the melting point of the fat. The fecal elimination of soap was increased significantly by the exclusion of pancreatic juice in the case of corn oil, triolein and tallow; was not significantly increased in the case of trielaidin; and was decreased in the case of tripalmitin, due probably to decreased hydrolysis. Exclusion of pancreatic juice increased the elimination of endogenous total lipid and of soap. Fat utilization was correlated more closely with the melting point of the fats than with their saturation, suggesting that the melting point is concerned in determining utilization more than any other characteristic of the fat.
Effect of Whole Body X-Irradiation on Plasma and Intestinal Cholinesterase and on Drug Responses of Isolated Intestinal Loops in the Rhesus Monkey, Rat and Guinea Pig
Authors: French Arthur B. , Wall Patricia E.
Published: December 2017

Cholinesterase activity and responses to pressure, acetylcholine, histamine and eserine were studied in isolated intestinal loops from 15 rhesus monkeys, 4 rats and 31 guinea pigs subjected to whole body x-irradiation, and in loops from paired control animals. Ileal and jejunal nonspecific cholinesterase levels were reduced in rats 48 hours after 650 r, and in guinea pigs 48 hours after 250 r, but not in rhesus monkeys 48 hours and 7–9 days after 800 r. Monkey plasma cholinesterase levels showed only a small preterminal decrease when measured daily after 800 r. The peristaltic responses of monkey and guinea pig intestinal loops to intraluminal pressure were normal at the above intervals after radiation. In monkeys, rats and guinea pigs the dose of acetylcholine required to elicit a contraction was unchanged by radiation regardless of whether threshold dose or the dose which produced 50% of the calculated maximal response was measured. The height of the maximum contractile response of monkey ileal and jejunal loops to acetylcholine was greater at both time intervals after radiation than in control loops. This difference was not found in rats or guinea pigs or in monkeys after histamine or eserine. These observations cast doubt on the idea that changes in intestinal cholinesterase activity or in the sensitivity of intestinal muscle to acetylcholine play a significant part in the vomiting and the changes in intestinal motor activity which follow x-irradiation.
Response of Dogs to Long-Term Cholesterol Feeding
Authors: Shull Kenneth H. , Mann George V.
Published: December 2017

Hypercholesteremias averaging 495 and 570 mg % were maintained in two female dogs for periods of 4 and 3 1/2 years, respectively, by cholesterol feeding. The serum beta-lipoprotein levels were also grossly elevated throughout these periods. Neither the level of fat calories nor the calorie balance appeared to affect significantly these serum lipid levels. Gross and microscopic examinations performed at autopsy on these two dogs failed to reveal any abnormalities in the cardiovascular system or liver.
Δ Protein, a New Fibrous Protein of Skeletal Muscle: Preparation
Authors: Amberson William R. , White John I. , Bensusan Howard B. , Himmelfarb Sylvia , Blankenhorn Brigitte E.
Published: December 2017

Δ protein, a previously unreported fibrous protein with an electrophoretic mobility greater than that of myosin, is extracted from rabbit muscle by solutions of high ionic strength. This protein forms a complex with myosin, designated as Δ-myosin. Partial purification of Δ protein is achieved by two independent methods. In the first method alcohol fractionation is used. In the second, a solution of Salyrgan is used to dissociate the precipitated Δ-myosin complex. In each method further purification is obtained by preparative electrophoresis. Neither method yields a product which is entirely homogeneous. Tropomyosin is present as a contaminant in alcohol-fractionated preparations, and has been isolated and crystallized. All efforts to derive Δ protein from the previously known fibrous proteins of muscle have failed.
Δ Protein, a New Fibrous Protein of Skeletal Muscle: Complex Formation With Myosin
Authors: Bensusan Howard B. , White John I. , Himmelfarb Sylvia , Blankenhorn Brigitte E. , Amberson William R.
Published: December 2017

A complex, Δ-myosin, is formed by the union of myosin with Δ protein. This complex may be demonstrated in several ways: a) it appears as a separate peak on the patterns of descending boundaries in electrophoresis, and has a mobility intermediate between the mobilities of myosin and D protein. b) It may be detected in the patterns of the ascending boundaries by the increase in the area of the myosin peak and the decrease in the area of free D protein. c) It may be seen in ultracentrifuge diagrams, and is best demonstrated in the synthetic boundary cell. In the mixtures of the three fibrous proteins, myosin, actin and Δ protein, it can be shown that Δ-myosin exists in the presence of an excess of actin. When isoviscous solutions of Δ protein and actomyosin are mixed, there is a rapid fall in viscosity. This fall indicates that some of the actomyosin has been dissociated. The Δ protein then unites with the free myosin to form Δ-myosin. Since Δ-myosin sediments more slowly than does the free myosin, and since the viscosity falls slightly when isoviscous solutions of Δ protein and myosin are mixed, we suggest that the myosin molecule is split during formation of the complex.
Metabolism of C13-Carboxyl-Labeled Propionate by the Isolated, Perfused Dog Gastrocnemius
Authors: Lifson Nathan
Published: December 2017

The metabolism of C13-carboxyl-labeled propionate was studied in the isolated perfused dog gastrocnemius muscle, both resting and contracting. Under the conditions employed, 9–13% of the respiratory CO2 was derived from the carboxyl carbon of propionate in the resting skeletal muscle preparation, and only 3–5% in the repetitively contracting gastrocnemius. Thus, during muscle activity, the carboxyl carbon of propionate contributed proportionally less to the metabolic mixture giving rise to CO2 than during rest. Evidence was obtained for the conversion of carboxyl-labeled propionate to carboxyl-labeled lactate by isolated skeletal muscle, but not for its incorporation into muscle glycogen. When acetate and propionate are administered simultaneously to resting muscle, the rate of conversion of the carboxyl carbon of propionate to CO2 is reduced to a much greater extent than that of the carboxyl carbon of acetate.
Afferent Projections to Posterior Lobe of the Cerebellum and Their Spinal Pathways in the Cat and in the Monkey
Authors: Morin F. , Lindner D. , Catalano J.
Published: December 2017

The projections to the receiving areas of the posterior cerebellar lobe (the paramedian lobule of the cat and the tonsil of the monkey) have been studied by the evoked potential method following stimulation of skin muscle and articular nerves of the hindleg. By means of acute cord incision an attempt was made to identify the spinal tracts responsible for the conduction of the different impulses. Results emphasize the prominence of cutaneous over muscle afferents and the fact that spinocerebellar pathways are functionally aspecific. The possible tracts involved in the transmission of those impulses are discussed.
In Vitro Conversion of Desoxycortisol to Cortisol by Adrenal Tissues in Ascorbic Acid Deficiency
Authors: Bacchus Habeeb
Published: December 2017

The influence of ascorbic acid nutrition on the ability of adrenal tissue to convert 11-desoxycortisol (compound S) to cortisol was studied. It was shown that this process of 11-beta-hydroxylation of desoxycortisol was decreased in ascorbic acid deficiency. Addition of ascorbate to preparations of normal adrenals with desoxycortisol enhanced the conversion. Ascorbate addition corrected the decreased 11-beta-hydroxylation ability of the adrenals of animals on the deficient fare for 13–25 days, but failed to affect the ability of the adrenals of animals on the fare for 35 days. Ascorbate decreased ( P < 0.01) the spontaneous formation of 17-OH,20,21-ketol corticosteroids by normal adrenals. The decreased spontaneous formation of these substances by the ascorbic acid deficient adrenal is corrected by ascorbate.
Metabolic and Acid-Base Changes Following Acute Cholinesterase Inhibition
Authors: Gold Armand J. , Weller John M. , Freeman Gustave
Published: December 2017

Dogs acutely intoxicated with the cholinesterase inhibitors, Parathion or Sarin, develop both respiratory and metabolic acidosis. The former results from respiratory failure and the latter probably from tissue oxygen deprivation secondary to circulatory failure aggravated by an accelerated oxygen demand due to cholinergic stimulation. Accumulation of lactic acid accounts for about half of the metabolic acidosis. Plasma inorganic phosphorus, potassium and glucose become elevated but only the phosphorus rise persists during concomitant artificial respiration. Hypoxia resulting from circulatory insufficiency appears to be a major factor in the shift of phosphorus and potassium from the cells. Excessive release of adrenaline is probably primarily responsible for hyperglycemia.
Nature of Serum Protein Changes in the X-Irradiated Dog
Authors: Goldwater William H. , Entenman Cecil
Published: December 2017

Serum protein, lipoprotein and glycoprotein patterns have been studied in irradiated dogs, using paper electrophoresis techniques. Alpha-1 globulin lipid decreases in the terminal stages following fatal doses of x-radiation, this change reflecting a loss of lipoprotein. Considerably increased levels of alpha-2-3 globulin lipid and polysaccharide in extremely sick or dying dogs results from increased concentrations of lipoproteins and glycoproteins. Decreased alpha-4 globulin polysaccharide is a function of a loss of glycoprotein, while slight increases of beta globulin lipid reflect gains of beta lipoproteins. The loss of alpha-4 and gain of alpha-3 glycoproteins, have been found as early as 10 days prior to irradiation death, and in the absence of lipoprotein or body temperature abnormalities. In dogs surviving irradiation doses near the ld50, transitory lipoprotein changes are slight, while glycoprotein derangements are more pronounced. Mechanisms underlying these various changes are discussed.
Metabolism of Chrysemys picta During Fasting and During Cold Torpor
Authors: Rapatz G. L. , Musacchia X. J.
Published: December 2017

Chrysemys picta Schneider, a fresh water turtle, is capable of withstanding lengthy periods of fasting and cold torpor. An investigation was made of the biochemical differences between specimens in cold torpor, 4° ± 2°C, for 4–8 weeks, fasting specimens at room temperature, 22° ± 4°C, for 6–8 weeks and fed controls at the same room temperatures. Respiratory quotients of controls, torpid and fasting turtles were: 0.814 ± 0.019, 0.744 ± 0.029, 0.719 ± 0.025. The specimens in cold torpor showed marked decreases in oxygen consumption, heat production and metabolic rate. The fasted turtles showed characteristic biochemical properties of decreased liver total fatty acids, decreased blood glucose, and increased urine uric acid levels. The specimens in cold torpor had increased liver total fatty acids, a significant increase in liver glycogenolysis and increased urine uric acid levels. It was concluded that fundamental metabolic and biochemical differences exist between turtles in cold torpor and fasting turtles, and that both experimental types differ from the fed controls.
Urea Excretion in the Camel
Authors: Schmidt-Nielsen Bodil , Schmidt-Nielsen Knut , Houpt T. R. , Jarnum S. A.
Published: December 2017

The nitrogen excretion was studied in the one-humped camel, Camelus dromedarius. When a growing camel was maintained on a low N intake (dates and hay) the amount of N excreted in the form of urea, NH3 and creatinine decreased to 2–3 gm/day. This decrease was caused by a drop in urea excretion from 13 gm to 0.2–0.5 gm/day. Urea given intravenously during low N intake was not excreted but was retained. (The camel like other ruminants can utilize urea for microbial synthesis of protein.) The renal mechanism for urea excretion was investigated by measuring urea clearance and glomerular filtration rate during a period of 7 months. During normal N intake about 40% of the urea filtered in the glomeruli were excreted in the urine while during low N intake only 1–2% were excreted. The variations in urea clearance were independent of the plasma urea concentration and of glomerular filtration rate, but were related to N intake and rate of growth. No evidence of active tubular reabsorption of urea was found since the urine urea concentration at all times remained higher than the simultaneous plasma urea concentration. The findings are not in agreement with the current concept for the mechanism of urea excretion in mammals. It is concluded that the renal tubules must either vary their permeability to urea in a highly selective manner or secrete urea actively.
Inhibition of Renal Tubular Function by Cold
Authors: Hernandez Thomas , Coulson Roland A.
Published: December 2017

In an attempt to inhibit the renal tubular production of NH3 and CO2, alligators were exposed for long periods of time to temperatures as low as 5°C. Cold increased the concentration of the urinary Na, Cl, Ca, Mg and glucose while it decreased the excretion of NH3, CO2 and phosphate. When the effect was maximal the composition of the urine closely resembled that of the plasma except for a decreased protein and somewhat elevated CO2 content. The fact that the injection of Diamox into cold alligators was necessary to reduce the CO2 to the plasma level would seem to indicate that carbonic anhydrase was not totally inhibited by cold. Although cold reduced the clearances of both thiosulfate and creatinine, their U/P ratios of about 6/1 were not affected by temperature changes. Since PO4 is normally excreted by the tubules of the alligator, this ion was injected to test the effect of cold on tubular excretion. With the decrease in temperature the PO4 U/P ratio fell from 30/1 to 5/1. It was concluded that cold almost eliminates renal tubular activity in the alligator. Several experiments were also performed on turtles with similar results.
Sodium and Potassium Distribution in Isolated Thymus Nuclei
Authors: Itoh Shinji , Schwartz Irving L.
Published: December 2017

Calf thymus nuclei isolated in nonaqueous media contained 238 µEq of sodium and 661 µEq of potassium/gm dry weight; calf thymus nuclei isolated in sucrose solution contained 87 ± 4.8 (S.E.) µEq of sodium and 244 ± 12.2 µEq of potassium/gm dry weight. In a series of experiments designed to survey the influence of various factors on the sodium and potassium contents of thymus nuclei isolated in sucrose, sodium proved to be the more stable constituent. Potassium was lost easily from the nuclei on prolonged standing at low temperature, on repeated washings, after incubation in potassium free media, particularly in the presence of pyridoxal, Hg++, phenol, m-cresol and urea. Chloroform extracts and TCA precipitates of the nuclei contained 7% and 30%, respectively, of the nuclear sodium, but no potassium.
Effect of Hyperthyroidism on Glycogen Content of the Isolated Rat Liver
Authors: Burton Stanley D. , Robbins Edward , Byers Sanford O.
Published: December 2017

A method is described for determining net changes in glycogen content of the isolated rat liver after 6 hours of perfusion using the glycogen content of the caudate lobe of the liver as a control value. A series of experiments was performed in which livers obtained from normal and hyperthyroid rats were perfused at low and high perfusate glucose levels and the glycogen content of the livers was determined before and after perfusion. It was found that the isolated liver from the untreated rat under artificial perfusion neither increases nor decreases appreciably in glycogen concentration during a period of six hours at either low or high glucose perfusate concentrations. In contrast, the isolated hyperthyroid rat liver, which is uniformly low in glycogen concentration, effects a marked increase in its glycogen concentration by the end of perfusion at high perfusate glucose concentration (above 600 mg.%). It was concluded that the data confirm the effect of thyroxine in depleting the liver of its glycogen content, and establishes that thyroxine-influences the metabolism of the hyperthyroid liver and its enzyme systems in promoting glycogen storage even in the presence of increased glucose metabolism.
Ascites Formation Without Sodium Intake in Dogs With Thoracic Inferior Vena Cava Constriction and in Dogs With Right-Sided Congestive Heart Failure
Authors: Ball Wilmot C. , Davis James O. , Goodkind M. Jay
Published: December 2017

Dogs were subjected to constriction of the thoracic inferior vena cava or main pulmonary artery and were deprived of food for a period of 4 days thereafter. In association with a high venous pressure, 60% of the dogs formed ascites despite the absence of Na intake. Measurements of T-1824 dye space provided evidence that plasma volume was not increased. An increase in urinary excretion of aldosterone was associated with a markedly reduced urinary Na excretion. The data are interpreted as supporting the concept that elevated venous pressure initiates edema formation in congestive heart failure and that renal Na retention occurs as a secondary phenomenon.
Effects of Central Excitant and Depressant Drugs on Locomotor Activity in the Monkey
Authors: Davis George D.
Published: December 2017

The effects of reserpine, chlorpromazine, phenidylate, amphetamine and meprobamate have been evaluated by highly quantitative spontaneous activity testing coupled with visual observation of rhesus monkeys. Normal monkeys and monkeys with inherent or induced locomotor hyperactivity were used. Reserpine and chlorpromazine produced a marked reduction in all activity when administered in quantities significantly smaller than those required to produce ‘taming.’ Phenidylate and amphetamine had a rather selective effect in drastically reducing the stereotyped pacing of the hyperactive animals. Meprobamate had no effect on the amount of spontaneous activity in any of the animals until dosages were employed which produced locomotor incoordination. No drug has been found to increase the amount of spontaneous locomotion in the monkey.
Factors Influencing Diuresis in Rats Following Total-Body X-Irradiation
Authors: Pentz E. Irene , Hasterlik Robert J.
Published: December 2017

An immediate diuresis has been observed in rats exposed to total-body x-irradiation ranging between 100 and 400 r. Since the highest dosage produced more consistent results, it was used in conjunction with extirpation of various glands and other organs in an effort to determine the mechanism that responds so promptly to x-irradiation. The anterior pituitary and the adrenal cortex are of prime importance in this reaction. Removal of the anterior lobe of the pituitary or removal of the adrenal glands is sufficient to completely inhibit diuresis following 400 r x-irradiation. This diuretic response is not dependent upon the presence of the posterior pituitary since animals having only this gland removed became diuretic following exposure to 400 r. The evidence suggests that the release of antidiuretic substances from tissues other than the posterior pituitary is under anterior pituitary-adrenal cortical control.
Projection of Fast Afferents to the Cerebral Cortex of Monkey
Authors: Gardner E. , Morin F.
Published: December 2017

The projection of fast afferents to the cerebral cortex of the monkey was studied in acute experiments, in which various lesions were made in the cervical cord, and chronic experiments, in which similar lesions were made under aseptic conditions. By stimulating various peripheral nerves and recording evoked potentials from sensory and motor cortex, it was found that section of dorsal funiculi generally causes no significant change in latency or threshold of evoked potentials. The paths still available include the spinothalamic tract contralaterally and an ipsilateral path the nature of which is still uncertain. These additional paths are available for several modalities. As in the cat, muscle afferents do not reach the medulla directly by way of dorsal funiculi. Chronic lesions of these funiculi cause little deficit in animals observed for several weeks or months. Latency of potentials recorded from motor cortex is longer than that of postcentral potentials. The former apparently use different thalamocortical projections. The predominant projection to both motor and sensory cortex is cutaneous.
Bacterial Factor in Traumatic Shock in the Rat
Authors: Friedman E. W. , Schweinburg F. B. , Yashar J. , Fine J.
Published: December 2017

Prophylactic antibiotic therapy prolongs the rat's tolerance of hemorrhagic shock and considerably increases the survival rate. This is evidence that a bacterial factor is involved in the failure to respond to transfusion. Four and one-half-hour tourniquet shock differs from hemorrhagic shock in the rat. It remains reversible even if the fluid therapy is withheld for as long as 18 hours, whereas hemorrhagic shock becomes irreversible after some 3 1/2 hours. This may be because 4 1/2-hour tourniquet shock is essentially dehydration shock and, therefore, less damaging than shock due to whole blood loss. This is indicated by the fact that the average survival rate in 4 1/2-hour tourniquet shock is 70% with saline therapy alone. Hence, there is less need to protect the rat with antibiotic therapy. Aureomycin increases the survival rate from 70% to 88%. The antibacterial defense is damaged in both types of shock; but, with the techniques employed to date, we have not been able to show that it is damaged to a greater extent in hemorrhagic than in tourniquet shock. Although the patterns of response to shock are in general the same in the rat as in the dog, the rat displays greater antibacterial resistance than the dog during the early hours of shock.
Effects of Epinephrine and Insulin on Glucose Disappearance in Eviscerated Dogs
Authors: Fritz Irving B. , Shatton Jennie , Morton John V. , Levine R.
Published: December 2017

Epinephrine infusions inhibited glucose disappearance in insulinized eviscerated dogs at both normoglycemic and hyperglycemic blood levels. In contrast, administration of epinephrine had no acute effects on glucose disappearance in noninsulinized preparations, regardless of whether the animals were mainted at low or high blood sugar levels. The action of insulin on the final distribution volume of galactose was not affected by the simultaneous infusion of epinephrine. These data, in conjunction with various findings in the literature, were interpreted to signify that the metabolic fate of glucose after the administration of insulin was different from that occurring at hyperglycemic blood levels in the absence of insulin.
Effect of Food Administration on Lipogenesis in Normal and Adrenalectomized Rats
Authors: Cohn Clarence , Joseph Dorothy
Published: December 2017

Normal and adrenalectomized rats were either force fed or allowed to eat ad libitum a high carbohydrate diet for 3–4 weeks. The food intake of the force-fed groups was adjusted so that the rate of weight gain of the normal animals was equal to that of normal rats eating ad libitum. During the last 2 days of life, C14-labeled sodium acetate was included in the diet and its rate of incorporation into body fat was measured. The results reveal that under these conditions, the force-fed adrenalectomized rat gained weight at the same rate as normal force-fed controls. Furthermore, the adrenal steroid deficient animal fed in this manner contained amounts of body fat and incorporated C14 into the lipid moiety in quantities that did not differ from those of force-fed normal rats. By contrast, the adrenalectomized rat eating ad libitum gained less weight, contained less body fat but incorporated more C14 into his fat fraction than normal controls. We conclude that in the well nourished state, no deviation from normal in lipogenesis exists in the animal lacking his adrenal glands.
Metabolism of Testosterone by Guinea Pig Liver and Kidney Homogenates
Authors: Kochakian Charles D. , Raut V. , Nall D. M.
Published: December 2017

Homogenates of adult male guinea pig liver and kidney are able to metabolize testosterone to androstenedione. No other metabolites were detected. Optimum conditions for the action of the enzyme(s) have been determined in regard to amount of tissue, preparation of homogenate, cofactor, ph, duration of incubation and amount of steroid. The kidney differed from the liver in its response to the addition of nicotinamide and requirements of DPN. The activity of the tissues was quite high; 12 gm of either tissue under optimum conditions was able to convert approximately 50% of 50 mg of testosterone to androstenedione.