bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of parathyroid extract on metabolism of sulfate in immature rats
Authors: Bronner Felix
Published: December 2017

Administration of parathyroid extract to immature rats that had been given S35 24 hours earlier resulted on the average in a 30% increase in the level of S35 in the plasma, a 25% higher output of S35 in the urine, a 17% increase in the pelt content of S35, and a 14% increase in the ratio (S35 in humerus ends:S35 in humerus shafts), as compared with litter mates treated with an inactive control solution. The findings are interpreted as indicating that calcium mobilization induced by the action of parathyroid hormone proceeds by removal of both organic and inorganic portions of bone. Concomitant histological observations confirmed the inference drawn from the chemical analyses, namely, that administration of parathyroid extract induced a higher than normal metabolic activity in the ends of the long bones and resulted in increased bone formation and resorption.
Incorporation of C14 from C14-labeled sugars into CO2, nucleic acids and protein by isolated rat diaphragm
Authors: Wool Ira G.
Published: December 2017

The metabolism by isolated rat diaphragm of the following C14-labeled sugars was investigated: d-glucose, d-xylose, d-galactose, d-mannose, d-fructose, d-ribose, l-sorbose, l-arabinose and d-arabinose. Three (d-glucose, d-mannose and d-fructose) were oxidized to C14O2 in significant amounts. C14 from only these same three sugars was incorporated into nucleic acids by isolated rat diaphragm. C14 from d-glucose, d-mannose, d-galactose and d-ribose was incorporated into diaphragm protein. The results provide no clue to the nonenergetic mechanism by which d-glucose, d-mannose, l-sorbose, d-xylose and d-ribose stimulate protein synthesis; they do emphasize the metabolic versatility of muscle.
Effect of ethanol administration on brain and liver enzyme activities
Authors: Kinard F. W. , Hay M. G.
Published: December 2017

Rats receiving daily administrations of ethanol for 10–12 weeks became demonstrably resistant to intoxicating effects of the alcohol by the 9th week. The increased resistance to the effects of alcohol was not accompanied by increased oxidation of alcohol in the intact animal or by increased oxidation of ethanol in liver homogenate. Brain AChE activity is reduced to a statistically demonstrable but functionally insignificant degree by administration of alcohol whether the rat is receiving its first dose or whether it has become tolerant to the intoxicating effects of alcohol. The development of tolerance to ethanol appears to be unrelated to the rate of oxidation of alcohol in either the intact animal or in liver tissue and does not appear related to changes in brain AChE activity.
Transient and long-lasting electrical responses to direct hippocampal stimulation
Authors: Kandel E. R. , Spencer W. A. , Brinley F. J.
Published: December 2017

Widely accepted use of the direct cortical response (DCR) for the study of neocortical apical dendrites prompted this study of the response of the surface of hippocampal pallium to direct electrical stimuli in rabbits anesthetized with Dial or Evipal. The hippocampus was directly exposed by radical decortication. The most typical response to direct hippocampal stimulation (DHR) is a monophasic 20–25 msec. negative wave. The DHR is linearly graded throughout the early part of its input-output curve, shows no refractoriness, exhibits long lasting (400 msec.) potentiation of a previously conditioned test response, is rapidly (3–5 sec.) inverted by GABA and is associated with two types of d.c. shifts: a) d.c. shift without concomitant loss of the DHR and b) a variant of spreading hippocampal depression. From these properties the DHR would appear to be quite similar to the DCR. However, different bioelectric generators must be postulated since the hippocampal neural geometry is different from neocortex with respect to the orientation of its predominant neurons.
Amylase in rat serum, submaxillary gland and liver following pilocarpine administration or normal feeding
Authors: Schneyer C. A. , Schneyer L. H.
Published: December 2017

Amylase levels have been determined for serum, submaxillary gland and liver of unstimulated and stimulated 48-hour fasted rats. Stimulation was by subcutancous administration of pilocarpine or by ad libitum feeding. Without stimulation, amylase levels of both liver and submaxillary gland were lower than that of serum. After stimulation by either means, amylase levels rose, but not proportionately, in serum, liver and submaxillary gland. The rise in liver amylase can be accounted for by increased amylase level of extracellular fluid. Rise in submaxillary gland amylase greatly exceeds that of serum and in this tissue may reach a value three to six times that of serum. An active process of amylase accumulation by submaxillary gland, possibly as a result of new synthesis, must be considered to account for this accumulation.
Effect of acetylcholine on nitrogen excretion in normal rats
Authors: Granitsas A. N.
Published: December 2017

Under certain conditons acetylcholine can produce a decreased nitrogen and creatinine excretion in normal rats. This effect is comparable, but not identical, to the action of 2.5 u of growth hormone under the same conditions.
K42 and Cl36 fluxes during ACh- and Ca-induced atrial fibrillation
Authors: Briggs Arthur H. , Holland William C.
Published: December 2017

K42 and Cl36 fluxes are compared in fibrillation induced by ACh and Ca in isolated rabbit atria. An increased Na ion movement appears to be important in the initiation and maintenance of both types of arrhythmias. Inactivation of this Na movement could be the result of an increased K efflux and/or an increased Cl influx. Potassium appears to make the predominant contribution to Na inactivation initially in ACh-induced fibrillation. Data are presented which show that in Ca-induced fibrillation Cl influx is markedly increased over that seen in the ACh-induced arrhythmia. Potassium efflux is also increased in Ca-induced fibrillation but to a much less degree than in ACh-induced fibrillation. It was concluded that Cl plays a major role in Na inactivation in the Ca-induced arrhythmia and that Cl movement is extremely important in initiating and maintaining both arrhythmias.
Influence of elevated venous pressure on flow and composition of renal lymph
Authors: LeBrie S. J. , Mayerson H. S.
Published: December 2017

Lymph was collected from renal capsular lymphatics in anesthetized dogs before, during and after periods of raised venous pressure produced by partial occlusion of the inferior vena cava. Renal lymph flow increased about five times during the period of elevated pressure. Electrolytes and protein flows changed proportionately except at high venous pressure (30–35 cm H2O) when disproportionately high levels of protein were found in renal lymph. Urine flow and sodium excretion decreased during the periods of elevated venous pressure. With increased venous pressure, lymph flow in one lymphatic may equal or exceed urine flow from the ureter of the same kidney. The results are interpreted as supporting the countercurrent hypothesis of urine formation and as indicating a possible role of the renal lymphatics in renal diseases and in the retention of sodium and water found in congestive heart failure.
Glomerular filtration and renal plasma flow during hyperthermia
Authors: Kanter G. S.
Published: December 2017

The purpose of this study was to investigate the factors that determine the direction and magnitude of the alteration in GFR (glomerular filtration rate) and RPF (renal plasma flow) in hyperthermia. The investigation was conducted on anesthetized dogs. Creatinine clearance was used as a measure of GFR and para-aminohippuric acid clearance was used as a measure of RPF. The GFR in 12 mildly dehydrated dogs went from a control value of 68.4 ± 4.5 ml/min. at RT (rectal temperature) of 38.9°C to a GFR of 25.1 ± 8.5 ml/min. at a RT of 42.1°C at the end of 5 hours of exposure to heat. Final dehydration averaged –2.0% body weight. The fall in GFR and RPF was not due to dehydration for in a group of six hydrated dogs (+4% body wt. at end) similar results were obtained. No decrease in GFR or RPF occurred in either hydrated or dehydrated dogs until severe hyperthermia (> 41.2°C) was present. Though there was a decline in blood pressure towards the end of each experiment, in both groups, the decrease in GFR and RPF preceded any marked fall in pressure. Both groups showed an increase in hematocrit and a decrease in plasma volume (measured by T-1824 dilution) which became marked at the end of 5 hours of exposure to heat. The decrease in GFR and RPF appears directly related to the hyperthermia for upon rapid cooling GFR and RPF increases towards normal in spite of the persisting decreased blood pressure and plasma volume and increased hematocrit.
Lipid changes in the perfusates of isolated rabbit hearts
Authors: Miller Harvey I. , Roheim Paul S. , Spitzer John J.
Published: December 2017

Rabbit hearts were perfused with different media using the Langendorff technique. Concentrations of the different lipid components were determined before and after perfusion. In experiments using hypercholesterolemic serums to perfuse normal hearts the concentrations of unesterified fatty acids (UFA) in the perfusates were above control levels, and esterified fatty acids were decreased. Total cholesterol did not change, free cholesterol increased, thus esterified cholesterol decreased. In about 50% of the experiments in which oleic acid-loaded albumin was used to perfuse normal hearts, an uptake of UFA occurred. Triglycerides were apparently not removed by rabbit hearts even when hypertriglycerolemic serum was the perfusion medium.
Responses of smooth muscles to quick stretch; relation of stretch to conduction
Authors: Burnstock Geoffrey , Prosser C. L.
Published: December 2017

Quick stretches applied to isolated strips of visceral muscles elicit contractions and electrical responses, similar stretches elicit no responses from blood vessels and nictitating membrane. Highly excitable muscles gave repetitive responses. Spontaneously active taenia coli relaxed in response to stretch and electrical activity diminished correspondingly. The membrane potential (sucrose gap measurement) decreased during stretch; spikes appeared at a critical level of depolarization. A single initial spike sometimes occurred before membrane depolarization. The membrane potential of spontaneously active muscle increased during stretch. Strips of smooth muscle mechanically immobilized in the center showed conduction from one side to the other; signals for both activation and relaxation were conducted. It is concluded that conduction can occur in absence of stretch, that quick stretch can alter membrane potential and thus alter excitability of smooth muscle.
Relationship of induced histidine decarboxylase activity and histamine synthesis to shock from stress and from endotoxin
Authors: Schayer Richard W.
Published: December 2017

The activity of histidine decarboxylase of various mouse tissues is increased by stress, by epinephrine and by endotoxins. Enzyme activity reaches a maximum in about 6 hours following a stimulus and returns essentially to normal within 1 day. In mice given a lethal dose of endotoxin, enzyme activity is at its highest observed level when the animals become moribund. Evidence is presented that the elevated enzyme activites reflect an increased rate of histamine synthesis in the living animal. The hypothesis of a homeostatic relationship between newly synthesized histamine and the catecholamines, which during intense stress can suffer imbalance, affords a reasonable explanation for the events observed in the small blood vessels during development of shock, for the damaging effects of epinephrine in endotoxin-treated animals and for a number of other phenomena related to shock.
Intestinal electrolyte absorption by parallel determination of unidirectional sodium and water transfers
Authors: Vaughan Burton E.
Published: December 2017

Plasma-to-lumen, lumen-to-plasma and net transfer rates for both sodium and water have been determined on dogs with Thiry-Vella loops, using a single transit perfusion. The net and lumen-to-plasma transfer rates of sodium are proportional to the concentration of sodium in the intestinal perfusate; net absorption of sodium ion occurs at all luminal sodium concentrations above 32 mEq/l. Water net transfer rate is inversely proportional to luminal osmolality; net absorption of water takes place at all luminal osmolalities up to 400 mOs/l. Hence, water must be actively transported and not transported exclusively as a passive osmotic consequence of sodium movement. Lumen-to-plasma water-transfer rates do not show a clear-cut osmotic dependency, owing to correlated sodium and water transfers. The regression slope of sodium on water transfer rates indicates the one-way transfer of an extremely dilute solution (42 mEq/l.), and this is true regardless of the composition of solution in the lumen. Such a phenomenon is a clear description of a fluid circuit mechanism.
Effect of acceleration on cerebellar potentials in birds and its relation to sense of direction
Authors: Gualtierotti T. , Schreiber B. , Mainardi D. , Passerini D.
Published: December 2017

T. Gualtierotti, B. Schreiber, D. Mainardi and D. Passerini, "Effect of acceleration on cerebellar potentials in birds and its relation to sense of direction." Page 473: The authors feel that there might be some misunderstanding in the interpretation of some of the data in table 1. The terms ‘mixed hybrids’ or generally ‘hybrids’ were not intended in the strict genetic sense, but in natural populations possibly inbred at random with homing pigeons. Therefore, the reported fifty-fifty distribution is not to be intended as a genetically valid datum concerning the inbreeding of controlled pure breeds: genetic work recently performed by the authors showed that the character studied (rotatory after discharges) has at last a partial dominance.
Cutaneous and muscle vascular responses to electrical stimulation of lumbar sympathetic trunk in the dog
Authors: Rawson Robert O. , Randall Walter C.
Published: December 2017

Simultaneous vascular responses in three cutaneous (thigh, calf, footpad) and one muscle (gastrocnemius) bed of the dog's hind leg were recorded during stimulation of the ipsilateral lumbar sympathetic trunk, and correlated with the vertebral level of stimulation. Changing patterns of vascular response with successively lower stimulations was interpreted to indicate the levels of preganglionic entry of vasomotor fibers into the sympathetic trunk. Significant variations in the anatomic patterns of vasomotor pathways were found. In a few animals vasoconstrictor fibers innervating only the proximal portions of the extremity were found in the more rostral portions (L2-L3) of the trunk. In others, however, these same segments of the trunk carried rich innervation to the most distal regions of the extremity. In a majority of animals, the most effective cutaneous vasomotor innervation entered the trunk between L3 and L5. There were notable instances of entry as low as the L6–L7 interganglionic segment. Both vasoconstrictor and vasodilator responses were elicited in the gastrocnemius muscle, frequently by stimulation at different levels of the trunk in a given animal. The dilator responses were readily abolished by intravenous administration of atropine, leaving constrictor reactions relatively unaffected.
Combined lethal effect of desoxyribonucleic acid injection and cholesterol feeding
Authors: Savitsky J. Philip
Published: December 2017

Highly purified, undenatured desoxyribonucleic acid (DNA) was prepared from homologous and heterologous tissues. One milligram of this DNA was injected into each of 21 rabbits, producing a lowered mean serum cholesterol and decreasing variation of the cholesterol levels. Four months after the DNA injection, the rabbits received a 0.5% cholesterol diet. The animals lost their appetite, lost weight, became debilitated, infected and died. One hundred per cent of the DNA-injected rabbits died within 3 months after starting the cholesterol diet compared to 5% of the cholesterol-fed controls. Gross autopsies revealed only debilitated animals with terminal infections. The nature and cause of the lethal effect are undetermined.
Acute effects of quinidine on K exchange and distribution in the dog ventricle
Authors: Conn Hadley L. , Wood John C.
Published: December 2017

Some of the effects of quinidine on potassium metabolism and gas exchange were studied in the isolated perfused dog heart. The major changes found were an increase in cell K and transcellular K exchange, and a decrease in oxygen consumption and respiratory quotient. The increase in K exchange was apparently due to an increased resting potential potassium exchange with little or no alteration in exchange during the action potential. The accumulation of cell K seemed to be dependent mainly on an initial resting phase increase in potassium influx.
Induction of hypertension in the frog by bilateral nephrectomy
Authors: Grollman Evelyn Frances , Grollman Arthur
Published: December 2017

Bilateral nephrectomy in the frog ( Rana pipiens, clamita and catesbiana) resulted in an elevation in systolic and diastolic blood pressure comparable to that observed in the mammal. These observations afford further evidence for the basic role of the kidney in the maintenance of the normotensive state.
Stop-flow analysis of ionic transfer in the dog parotid gland
Authors: Langley L. L. , Brown R. S.
Published: December 2017

Radioisotopes of K, Na, I, Ca and P were used. In the first series, saliva flow was stopped by closing the outlet valve. The isotope was then injected into the ipsilateral artery. Saliva was collected serially in two-drop samples. In the second series, a constant blood level of isotope was maintained. Saliva flow was stopped for 90 seconds. The first series shows that each isotope has a specific area for maximum transfer. This is most distally in the duct for calcium and least distally for iodine with the others falling between these two extremes. Because these transfers occur in the first few drops collected, and because autoradiographs have shown iodine to be most concentrated in the duct it is concluded that all of the ions studied in this series are transferred to the saliva by the duct cells. The second series shows that during flow stoppage, sodium and chloride concentration in the ducts usually decreases while potassium, calcium, iodine and phosphorus concentration increases. The fact that all of these changes are limited to the duct further supports the conclusion that ionic transfer takes place exclusively in the ducts. A recirculation of sodium and chloride between the plasma and saliva is postulated.
Site of absorption of Co60-labeled vitamin B12 in the male albino rat
Authors: Moertel Charles G. , Scudamore Harold H. , Owen Charles A. , Bollman Jesse L.
Published: December 2017

This study was undertaken to determine the site of maximal absorption of Co60-labeled vitamin B12 in the small intestine of the male albino rat. Animals were sacrificed at intervals after ingestion of the labeled vitamin. The highest concentration of radioactivity was found in the wall of the upper and mid-ileum 1/2–3 hours after ingestion. Accordingly, the absorption of tagged vitamin B12 was estimated by fecal and urinary excretion methods in animals with resections of portions of the small intestine, including the portion containing the ileocecal valve, and in normal controls. Resection of the middle half of the small bowel (the upper and mid-ileum) was found to produce significant impairment of vitamin B12 absorption. It is concluded that in the male albino rat the upper and mid-ileum is specifically adapted to most efficient absorption of vitamin B12.
Mechanism of mast-cell disruption induced by a principle extracted from Ascaris suis
Authors: Uvnäs Börje , Diamant Bertil , Högberg Bertil , Thon Inga Lisa
Published: December 2017

A mast-cell disrupting factor was obtained from Ascaris suis. The ground material was extracted with 50% ethyl alcohol, concentrated in vacuo, washed with ether, dialyzed and kept in 50% alcohol. Further purification could be obtained on Amberlite IRC-50 column or charcoal. The influence of pH, temperature, ionic milieu and enzyme inhibitors on the disrupting action of the Ascaris factor on rat mesentery mast cells in vitro suggested that the cell disruption involves the activation of an enzymatic process localized to the mast cell. The possibility that the activation of a phospholipase triggers an energy requiring disruption process is discussed. The mechanism seems to be the same as for mast-cell disruption due to polymer amines (such as compound 48/80) and antigens.
Thermogenic and adaptive mechanisms in hibernation and arousal from hibernation
Authors: Mokrasch L. C. , Grady H. J. , Grisolia S.
Published: December 2017

The process of arousal from hibernation is begun by a temperature rise in the foreparts of the gopher which precedes any rise in oxygen consumption. This is followed by a rapid change of the R.Q. from values near 0.7–1.0 and an acceleration of O2 consumption. The rate of heat production appears to exceed that calculated from the O2 consumption until the arousal process is more than half complete. The probable source of this heat is the store of energy rich compounds in the body. The P/O ratio of liver particles was shown to be identical for the normal and hibernating hamster contrary to what would be predicted from current theory. Perfusion experiments with isolated hearts of rat, normal and hibernating hamster reveals no detectable humoral activity in the blood of hibernating hamster.
Net absorption of water, chloride and hexose from the intestine of dogs
Authors: Annegers John H.
Published: December 2017

Hexose and/or NaCl solutions were perfused at about 100 cm H2O pressure through small intestinal loops in unanesthetized dogs. The rate of glucose absorption increased in curvilinear fashion as the glucose concentration of the infusate ranged from 1% to 30% and did not differ between jejunal and ileal loops. Net chloride secretion rates were independent of perfusate hexose concentrations and were greater for jejunal than for ileal loops when nonchloride solutions were infused. Net chloride absorption rates increased with infusate concentrations ranging from 0.2% to 1.8% NaCl, and were greater for ileal than for jejunal loops. However, this difference may be due to the greater chloride secretion of jejunal loops. The curvilinear relationship between moles of glucose or chloride absorbed and lumen concentrations of these substances was rectified by plotting absorption rates against log concentration. The resulting Δ mm absorbed per hour/Δ log mm per liter concentration of the perfusate averaged 10.1 and 8.7 for chloride and glucose, respectively, in 6 dogs. Net fluid absorption rate decreased in curvilinear fashion with increasing perfusate osmolar concentration when NaCl or hexose was given. Net fluid absorption at given osmolar perfusate concentrations was greater from NaCl than from glucose or sorbose solutions.
Considerations of oxygen-hemoglobin equilibrium in the physiological state
Authors: Gomez Domingo M.
Published: December 2017

A formulation is presented, which applies to the oxygen-hemoglobin equilibrium under physiological conditions. This formulation fits with excellent accuracy the experimental data obtained by various authors in man and in several animal species. The marked difference in the comportment of intracellular and dilute hemoglobin is emphasized. It is indicated that Adair's four compounds hypothesis does not apply in its simplest form to intracellular hemoglobin, unless different values for different O2 partial pressures are given to the association ‘coefficients’ and in particular to that of the fourth hemoglobin compound.
Conditions affecting rate of development of anoxic block in C fibers
Authors: Crowley W. J. , Thomson M. A.
Published: December 2017

The isolated splenic nerve of sheep conducted impulses for an average of 10 minutes in the complete absence of oxygen at 37.5°C. If, immediately following conduction failure, the nerve was allowed to recuperate for 2 hours in oxygen it became able to conduct impulses as long during a repeated period of anoxia as it had initially. If the initial period of anoxia was prolonged beyond 28 minutes the nerve sustained irreversible damage and its ability to conduct impulses during subsequent periods of anoxia was shortened proportionally. For recuperation periods shorter than 2 hours the conduction block during the course of the second period of anoxia appeared earlier. Temperatures below 37.5°C or CO2 concentrations above 10% prolonged the time to conduction block during anoxia; temperatures above 37.5°C or frequencies of stimulation greater than 1/sec. shortened the time to conduction block during anoxia.
Responses of cardiac tissue to certain stimulants and inhibitors
Authors: Merrick Arthur W.
Published: December 2017

Rat heart slices were incubated in variable concentrations of 1) epinephrine, 2) iodoacetic acid, 3) sodium fluoride, 4) 2,4-dinitrophenol and 5) insulin. The acid-soluble ( A) and acid-insoluble ( B) glycogen fractions, as affected by these drugs, were investigated. Degradation of A was observed with all concentrations of 1 and 4 but occurred only in the stronger solutions of 2 and 3. Glycogenolysis was noted in B in both concentrations of 4, only in the stronger dosage of 3, and a glycogenolytic trend was observed in 1. The concentrations of 5 used in these experiments had no effect on A and B of rat ventricular slices. Parameters associated with the design of an experiment influence markedly the effects these drugs have on the functional vacillations of tissue glycogen.
Variations in serum lipids with fibrinolytic and proteolytic activity in dogs and rabbits
Authors: Bang Nils U. , Cliffton Eugene E.
Published: December 2017

It was observed in dogs and rabbits that the infusion of high doses of plasminogen-activator-plasmin mixtures, resulting in a potent proteolytic and fibrinolytic state, was accompanied by a striking decrease in serum total cholesterol and phospholipid. This effect has been observed in 6 fasting dogs, in 7 dogs during alimentary lipemia, and in 11 rabbits rendered lipemic through the addition of 2% cholesterol to their diet for 5 weeks prior to the experiments. In the dogs cholesterol and phospholipid values remained constant during a 3-hour control period; during a 5-hour period of infusion of streptokinase and diluted human plasma the mean percentage decrease was 42% for cholesterol and 44% for phospholipid. Diluted human plasma without streptokinase had no effect on serum cholesterol and phospholipid levels. In rabbits the infusion of the inactive protease precursor plasminogen had no effect on lipid levels, while the infusion of streptokinase-activated plasmin resulted in an average decrease of 24% for cholesterol and 17% for phospholipid.
Metabolism of C14- labeled substrates in kidney cortical slices from normal and alloxan-diabetic rats
Authors: Flinn Robert B. , Leboeuf Bernard , Cahill George F.
Published: December 2017

The metabolism of C14-labeled glucose, fructose, mannose and pyruvate was studied in kidney slices from normal and alloxan-diabetic rats. Labeled carbon was recovered in CO2, glycogen and fatty acids. The rate of mannose metabolism was consistently slightly less than that of glucose, and on the other hand, the rate of fructose metabolism was consistently greater. In slices from alloxan-diabetic animals the metabolism of glucose and mannose was markedly reduced; that of fructose was only slightly decreased. No effect of insulin added in vitro could be demonstrated on glucose metabolism. Pyruvate oxidation to CO2 was slightly increased in slices from diabetic animals. Furthermore, glucose production was increased sixfold by diabetes and, as calculated, 75% of this glucose production could be accounted for by glucose synthesized from labeled pyruvate. The similarity between carbohydrate metabolism in liver and kidney was pointed out.
Differences in cholesterol oxidation and biosynthesis in liver of male and female rats
Authors: Kritchevsky David , Staple Ezra , Rabinowitz Joseph L. , Whitehouse Michael W.
Published: December 2017

Female rat liver mitochondria oxidized cholesterol-26-C14 and sodium pyruvate-2-C14 to C14O2 to a much greater extent (per mg N) than did male rat liver mitochondria. Mitochondrial preparations from livers of castrated, estrogenized or castrated-estrogenized male rats all oxidized cholesterol-26-C14 to a greater extent than did liver preparations from normal male rats. No differences were observed in the oxidation of sodium octanoate-1-C14. The serum and liver cholesterol levels of the feminized rats were higher than those of the intact males. Biosynthesis of cholesterol from sodium acetate-2-C14 by male rat liver homogenates was significantly lower than biosynthesis by liver homogenates from normal female rats or gonadectomized rats of both sexes. The rate of biosynthesis from mevalonic acid-2-C14 by liver homogenates from castrated male rats was much higher than in homogenates of oophorectomized females or intact males or females. Differences in sex or gonadectomy had no effect on biosynthesis of fatty acids from sodium acetate-2-C14.
Central effects of succinylcholine and decamethonium on monosynaptic reflexes
Authors: Fujimori Bunichi , Eldred Earl
Published: December 2017

Observations have been made in cats upon central mechanisms responsible for reduction in monosynaptic responses of triceps surae motoneurons following intravenous injection of decamethonium or succinylcholine. Two-thirds of extensor motoneurons show an increase in random firing under the influence of these drugs. Interference by this enhanced discharge with potentials induced in the ventral root and horn by stimulation of the ventral root was demonstrated. Monosynaptic responses are reduced in some motoneurons which are not caused to fire randomly with SCh injection. Depression of the monosynaptic reflex by SCh is attenuated in animals treated with dihydro-beta-erythroidine or strychnine, suggesting the presence of inhibition in the SCh effect. Monosynaptic reflexes of flexor muscles are reduced by SCh. This indicates that inhibition by the enhanced discharge of flower-spray afferents is not requisite. Supraspinal levels are not essential for appearance of the SCh effect.
Vascular responses to catecholamines during respiratory changes in pH
Authors: Nash C. W. , Heath C.
Published: December 2017

The influences of hypercapnia and hyperventilation on peripheral vascular responses to adrenaline and noradrenaline were observed in lightly anesthetized dogs. Changes in the carotid artery blood flow and pressure induced by intra-arterial doses of these amines were measured before, during and after the respiratory changes. During hypercapnia and low blood pH there was a reduced peripheral vascular response, while during hyperventilation and a high pH the vascular response to these drugs increased. However, a fall in blood pressure and flow, and a reflex elevation of the peripheral resistance occurred during both the hyperventilation and the posthypercapnic periods. It appeared that the elevated responses to the amines during those periods of high vasomotor tone may have been produced, in part at least, by the geometric factors involved in resistance, and not entirely by an increased response of the vascular smooth muscle.
Effects of cold acclimation on lipid metabolism in adipose tissue
Authors: Patkin Judith K. , Masoro E. J.
Published: December 2017

Cold acclimation is known to alter hepatic lipid metabolism. Liver slices from cold-acclimated rats have a greatly depressed capacity to synthesize long-chain fatty acids from acctate-1-C14. Since adipose tissue is the major site of lipogenic activity in the intact animal, its fatty acid synthetic capacity was studied. In contrast to the liver, it was found that adipose tissue from the cold-acclimated rat synthesized three to six times as much long-chain fatty acids per milligram of tissue protein as the adipose tissue from the control rat living at 25°C. Evidence is presented indicating that adipose tissue from cold-acclimated and control rats esterify long-chain fatty acids at the same rate. The ability of adipose tissue to oxidize palmitic acid to CO2 was found to be unaltered by cold acclimation. The fate of the large amount of fatty acid synthesized in the adipose tissue of cold-acclimated rats is discussed.
Collagen metabolism of rats in various hormonal and dietary conditions
Authors: Smith Q. T. , Armstrong W. D.
Published: December 2017

Injections of glycine-2-C14 into male rats were followed by determination of specific activity of femur and tail tendon collagen glycine and free plasma glycine. Hydroxyproline contents of bones were used to calculate total collagen glycine radioactivities. Although part of the femur collagen was relatively metabolically stable, a slow replacement appeared to take place. Specific activities of tail tendon collagen glycine, in contrast to femur collagen glycine, increased from 3 to 7 days after isotope administration. This difference appeared to be related to specific activities of free plasma glycine. Animals on an inadequate diet presented a different pattern of isotope content than animals on a complete diet. Results with hypophysectomized animals indicated turnover of femur collagen. Hypophysectomy resulted in a differential effect on femur and tail tendon collagen. Parathyroid-extract treatment increased the total collagen content of femurs. During certain experimental periods, specific activities of femur and tail tendon collagen glycine of parathyroid-treated animals approached the specific activity of free plasma glycine more rapidly than normal animals.
Effect of bacterial endotoxemia on succinic dehydrogenase of liver and kidney of rabbit
Authors: Cascarano J. , Rubin A. D. , Neumann A. K. , Zweifach B. W.
Published: December 2017

The in vivo inhibition of liver and kidney succinic dehydrogenase by administration of lethal doses of bacterial endotoxin ( Escherichia coli and Salmonella typhosa) was investigated. Quantitative determinations conducted on tissue homogenates revealed significant inhibition of activity only in liver of rabbits injected with E. coli lipopolysaccharide. The histochemical distribution of succinic dehydrogenase in fresh frozen sections of kidney was the same in both control and experimental animals. However, the centrolobular areas of liver appeared considerably depressed in activity in both E. coli and S. typhosa endotoxin-treated animals. These data, along with those presented by other studies in the literature, suggest that the action of endotoxin appears to be restricted to certain cells.
Effect of normal microbial flora on intestinal surface area
Authors: Gordon Helmut A. , Bruckner-Kardoss Edith
Published: December 2017

The mucosal surface area of the small intestine was determined in young adult, germfree and conventional rats. On the average, the germfree values were found to be 30% lower than those of conventional animals. This reduction was pronounced in the mid- and lower parts of the small intestine and relatively slight in the upper segment. It is assumed that the higher surface area values of conventional rats are due to the "physiologic" stimulation by the normal microbial flora.
Effects of dihydroergotamine in athyroid and thyroxinized rats
Authors: Sawyer Horace K. , Lipner H. J.
Published: December 2017

Athyroid and athyroid-thyroxinized rats showed an increase in oxygen consumption that was linear with the log of the dose of thyroxine. Epinephrine elevated the level of O2 consumption, but the response was still linear with respect to the log of the thyroxine dose. Dihydroergotamine had a slight depressant effect on the O2 consumption of all groups, but did not affect the linearity of response. Epinephrine plus dihydroergotamine caused a response similar to that seen when no drugs were administered. The effects of the various treatments on blood sugar levels were exactly parallel to those obtained with O2 consumption measurements. The data do not support the concept that the action of thyroxine on tissues of the organism is mediated via epinephrine.
Renal tubular transport of nitrofurantoin
Authors: Buzard James A. , Bender Raymond C. , Nohle Esther G. , Humphrey Donald T. , Paul Mary F.
Published: December 2017

Tubular secretion of nitrofurantoin has been demonstrated in the dog and the chicken. This secretion has been localized in the proximal tubule and has been shown to be due to the action of the weak acid transport system. Reabsorption of nitrofurantoin by passive, nonionic diffusion has also been illustrated.
Influence of monoamine oxidase inhibitor on contractility of isolated rat hearts
Authors: Meijler F. L. , Durrer D.
Published: December 2017

Following the suggestion that monoamine oxidase inhibitor might interfere with potentiation of cardiac contractions, the influence of 1-iso-nicotinyl-2-isopropyl-hydrazide and 1-pivaloyl-2-benzyl-hydrazine on postextrasystolic increase of isotonic contractions in isolated perfused rat hearts was studied. It was found that monoamine oxidase inhibitor did not change the increase in contractility following an interpolated or a noninterpolated premature beat. The metabolic process by which cardiac muscle varies its contractility with varying cycle length remains unknown.
Heart rate and blood lactic acid concentration during experimental diving of water snakes
Authors: Murdaugh H. V. , Jackson Joseph E.
Published: December 2017

Bradycardia in response to submersion occurs in Natrix sipedon and Natrix cyclopion. Atropine will prevent this diving bradycardia. Blood lactic acid concentration does not increase during submersion, indicating the presence of an arterial constrictor response in these species of water snake. The diving phenomenon of the water snake appears similar to the diving phenomenon of the seal in that both diving bradycardia and arterial constrictor response occur.
Effect of infused epinephrine after ganglionic block on histamine depressor response
Authors: Hilton James G.
Published: December 2017

The effects of infusion of epinephrine to a fixed maintained blood pressure level, after blockade of the ganglia by the administration of hexamethonium, on the blood pressure responses to histamine have been studied in the dog anesthetized by the intravenous injection of 30 mg/kg of pentobarbital sodium. The blood pressure levels maintained by the infusion of epinephrine were 100, 130, and 160 mm Hg. The doses of histamine tested were 1.0, 5.0, and 10.0 µg/kg. Blood pressure was measured from the carotid artery by means of a mercury manometer. Following each dose of histamine during the control period and at each infusion-maintained blood pressure level the blood pressure responses were analyzed in terms of minimum attained blood pressure, actual fall in blood pressure (depressor response), and duration of fall in blood pressure. The results of these experiments have shown that the depressor response to histamine is not affected by the blockade of the ganglia or the infusion of epinephrine. The minimum attained blood pressure is directly related to the level of the blood pressure at the time of the histamine administration and therefore a function of the quantity of epinephrine infused. From these results it has been concluded that epinephrine is not antagonistic to the histamine depressor response, but will alter the minimum blood pressure through its effects on the preinjection control blood pressure.
Effect of cadmium on renal tubular sodium transport
Authors: Vander Arthur J.
Published: December 2017

The discovery of a cadmium-containing protein, metallothionein, in renal cortex prompted these experiments, performed on anesthetized dogs undergoing saline diuresis. Both ureters were catheterized, and standard clearance techniques were employed. After completion of at least three control clearance periods, cadmium (as CdCl2), 0.35–4.46 µm/kg, was infused i.v. over 10 min. Cysteine was also infused to prevent or minimize blood pressure, glomerular filtration rate (GFR), and renal plasma flow decreases induced by cadmium. After all 17 injections, sodium excretion decreased, (UNaV)cont – (UNaV)Cd = 46–275 µm/min. The dose-response curve appeared to be hyperbolic; peak effect was usually 30 min after injection; range was 15–50 min. There was no change in GFR during these same periods; the average GFR ratio (Cd/control) for all experiments was 1.01 ± 0.03. Plasma sodium also was unchanged. Direct left renal artery infusion of cadmium produced increased sodium reabsorption, either limited to the left or greater than that on the right. These experiments establish the ability of cadmium to increase tubular sodium reabsorption by a direct renal effect.
Local effects of various anions and H+ on dog limb and coronary vascular resistances
Authors: Molnar J. I. , Scott J. B. , Frohlich E. D. , Haddy F. J.
Published: December 2017

The effect of intra-arterial infusion of an isosmotic solution of various sodium salts and acids on pressure gradients in the forelimb and heart was studied during constant rate blood perfusion. Forelimb resistance was reduced by Na pyruvate, Na acetate, Na nitrite, and Na citrate, by hydrochloric, nitric, lactic, pyruvic, acetic, and citric acids, and unchanged by NaCl, NaHCO3, NaNO3, and Na lactate. The molecular activity of Na acetate or Na nitrite exceeded that of Na pyruvate. All changes resulted mainly from fall of small vessel resistance. Na acetate also increased venous resistance, probably by a remote mechanism, and limb weight; the latter was more pronounced in the absence of artificial blood perfusion. Coronary resistance was decreased by Na acetate, Na nitrite, and Na citrate, increased slightly by NaHCO3, and unchanged by NaCl and Na lactate. Hence, the local effect of slight excess blood pyruvate, acetate, nitrite, citrate, or hydrogen is active arteriolar dilation, the activity of acetate or nitrite exceeds that of pyruvate, and acetate greatly increases tissue water storage.
Frequency arrangement in anterior ectosylvian auditory cortex of dog
Authors: Tunturi Archie R.
Published: December 2017

The anterior ectosylvian (AES) area was studied with local applications of strychnine and stimulation of the ear with known frequencies. The threshold spikes for various frequencies were determined to locate the connections to the area. It was found that low frequencies produced spikes ventrocaudally and higher frequencies produced spikes dorsocephalically. Each patch responded to a wider band of frequencies than observed in other areas. The same general arrangement, although less distinct, was obtained for both AES and MES (middle ectosylvian) areas in the lightly anesthetized dog, using only the evoked potentials as indicators. Considerable variation was found between animals and this variation was thought to be due to development of the nervous system. It was found that a sulcus generally separated the AES and MES areas. Other branch sulci of the ectosylvian sulcus penetrated the MES area, distorting the frequency pattern for sounds. The threshold data for the anesthetized dog in the AES and MES areas agree in absolute values to the minimum audible pressure levels for human hearing.
Effects of ethanol on cellular membrane potentials and contractility of isolated rat atrium
Authors: Gimeno Alvaro L. , Gimeno Martha F. , Webb J. Leyden
Published: December 2017

The simultaneous effects of ethanol on the contractility and electrical characteristics of atrial cells were examined. Single cell membrane potentials were determined using microelectrodes; the mechanical activity was recorded from a sensitive strain gauge. Ethanol at concentrations between 24 and 192 mm (110–880 mg/100 ml) depresses the contractility of the rat atria, the relationship between contractile depression and concentration being essentially linear. The effects are reversible in all cases. A definite shortening of the action potential, simultaneous with the reduction in contractility, is the most characteristic change in the electrical properties. This results from a more rapid rate of repolarization. The magnitude of the action potential is decreased slightly, whereas the resting potential and the depolarization rate are unaffected by ethanol. The depression of the contractility can be partially attributed to the shortening of the action potential but, in addition, there would appear to be some more direct action on the contractile mechanism. The decrease in the duration of the action potential may predispose the atria to dysrhythmias, such as ectopic beats and fibrillation.
Effects of Escherichia coli endotoxin on rat platelets
Authors: Roy Albert J. , Djerassi Isaac , Neitlich Harvey , Farber Sidney
Published: December 2017

Administration of E. coli endotoxin to normal rats results in a gradual and profound decrease of the levels of circulating platelets. In vitro incubation of fresh platelet-rich rat plasma with this endotoxin does not affect the platelet count. The osmotic fragility of the platelets, determined by release of acid phosphatase is, however, increased. The survival of endotoxin-treated platelets, estimated by their ability to circulate in thrombocytopenic rats, is markedly reduced.
Diencephalic placement of estradiol and sexual receptivity in the female rat
Authors: Lisk Robert D.
Published: December 2017

Behavioral receptivity, as indicated by the presence of the lordosis reflex, could be elicited from spayed rats after implantation of estradiol in the medial-basal preoptic and anterior hypothalamic regions. Hormone implants elsewhere in the hypothalamus or blank tubing implants throughout the hypothalamus did not produce this effect. Subcutaneous implants were equally ineffective for producing behavioral receptivity.
Effect of Dibenzyline on the metabolic actions of epinephrine and thyroxine
Authors: Schwartz Neena B.
Published: December 2017

Several investigators have attempted to use Dibenzyline to block the metabolic effect of thyroxine as a test of the "epinephrine hypothesis" of thyroxine function. The assumption underlying the use of the drug is that it blocks the hypermetabolism which follows epinephrine administration. This has been tested experimentally and found not to be justified. Dibenzyline does not block specifically the metabolic rate response as measured at 30 C to epinephrine, thyroxine, or a combination of the two hormones. Dibenzyline, thyroxine, and epinephrine show numerous interactions on rate of metabolism, blood glucose, and rectal and surface temperatures, but the Dibenzyline experiments are probably not meaningful in elucidating the role of epinephrine in the peripheral effects of thyroxine.
Gastric mucus production in Rana pipiens
Authors: Mizell Sherwin
Published: December 2017

The production of gastric mucus in vitro by Rana pipiens was studied using histamine stimulation. The frogs were kept at a constant temperature (21 C) both prior to and during experimentation. Quantitative determinations of mucoproteose, mucoprotein, and mucoid of the visible mucus were performed over a 13-month period, utilizing 340 animals in terminal experiments. Mucoproteose constituted one-half of frog gastric mucus, the rest being divided almost equally between mucoprotein and mucoid. No significant differences in this ratio or in the total amount of gastric mucus could be attributed to the change of seasons or to the addition of glucose or inosine triphosphate as substrates. A statistically significant negative correlation exists between both total mucus and mucoproteose and total acid produced. The mucoproteose fraction of gastric mucus may contain the inhibitor found by other investigators in human gastric juice. However, until further information is available on its physiological significance in situ, gastric mucus cannot be considered responsible for the seasonal variation of gastric HCI secretion in Rana pipiens.