bluuebunny/crossref_metadata_2025 huggingface dataset:
Hematocrit value of blood expressed from the isolated perfused kidney
Authors: Morgan Donald P.
Published: December 2017

Isolated dog kidneys were perfused with blood supplied from the carotid artery and returned to the jugular vein. The kidneys were enclosed in a rigid fluid-filled box. When the circulation was temporarily interrupted, about half the estimated total volume of intrarenal blood could be expelled by forcing fluid into the box. Hematocrits of the expressed blood were only slightly lower than hematocrits of arterial and venous blood samples taken during perfusion.
Nature of the thrombin-inhibiting effect of incubated fibrinogen
Authors: Triantaphyllopoulos D. C.
Published: December 2017

This study investigated the effect of a number of factors on the inhibition of thrombin by the anticoagulant fraction of incubated fibrinogen (AFIF). Heating above 46°C reduces and at 55°C completely abolishes the thrombin-inhibiting activity of AFIF. The prolongation of the thrombin time of fibrinogen by AFIF is proportional to the pH of the reaction mixture, while that of plasma tends to level off beyond pH 7.5. Calcium and magnesium up to a concentration of 10 mm shorten the thrombin time of both plain fibrinogen and fibrinogen mixed with AFIF in a proportional manner. AFIF partially inhibits the thrombin time reducing property of protamine on fibrinogen. Related probably to this is the observation that AFIF and serum protect purified fibrinogen from precipitation by protamine. The inhibitory effect of AFIF on the action of thrombin on fibrinogen was found to be competitive in nature. The hydrolysis of tosylarginine methylester by thrombin was shown to be unaffected by AFIF. The properties of the anticoagulant studied did not allow its identification with heparin.
Comparison of effects of acidosis and alkalosis on the renal action of Diamox
Authors: Brodsky William A. , Satran Richard
Published: December 2017

Diamox was given to anesthetized hydropenic dogs by single intravenous injection in doses of 10–1000 mg/kg in order to establish a dosage-response pattern. Increments of urine bicarbonate excretion were 60 µm/min. after doses of 10 mg/kg, 400–500 µm/min. after doses of 100 mg/kg, 700–1000 µm/min. after doses of 300 mg/kg and 600–1180 µm/min. after doses of 500–1000 mg/kg. Urine flow was dependent predominantly on effective osmotic load, indicating that the diuretic action of Diamox did not affect the distal mechanism for water transport. Bicarbonate accounted for 30% of the urinary solutes. Alkalinizing effects of Diamox, similar to those of NaHCO3, were found in dosages of over 300 mg/kg. Hence, the dosage used for evaluation of drug effect was restricted to the range 20–200 mg/kg. The action of Diamox was reduced to one half to one sixth of that expected when given to dogs under conditions of both metabolic and respiratory acidosis. For example, the increment of bicarbonate excretion was no more than 200 µm/min. after doses of 20–200 mg/kg. Such suppression of a drug action during acidosis was independent of glomerular clearance as well as of serum levels of HCO–3 and Na+. The action of Diamox under conditions of metabolic alkalosis or under normal conditions was greater than that observed under acidotic conditions. The relation of a postulated carrier-anhydrase molecule to Diamox inhibition under different conditions of plasma and urinary acidity is discussed.
Localization of urate transport in the nephron of mongrel and Dalmatian dog kidney
Authors: Kessler Richard H. , Hierholzer Klaus , Gurd Ruth S.
Published: December 2017

Localization of urate transport within the nephrons of mongrel and Dalmatian dogs was studied by stop-flow analysis. In mongrel dogs urate concentrations and clearance ratios were lowest in the segment in which PAH was secreted. Urate clearance ratios of 0.7 in free-flow samples were reduced to about 0.3 in stop-flow samples from the proximal segment. In the distal segment urate clearance ratios did not differ significantly from ratios obtained in free-flow. Probenecid, in doses sufficient to block PAH secretion, inhibited urate reabsorption thereby increasing urate clearance. In contrast to these findings with mongrel dogs, the Dalmatians exhibited weak but definite urate secretion within the proximal segment. The action of probenecid in this strain of dogs was to stop all proximal secretory activity for urate thereby reducing urate clearance. It was suggested that mongrel and Dalmatian dogs transport urate by systems that are identical except for direction of urate movement.
Influence of free blood exchange between two animals on some body fluid compartments
Authors: Greenfield Wilbert , Horvath Steven M.
Published: December 2017

The changes in systolic, diastolic and mean arterial pressures, heart rate, cardiac output, pulmonary and peripheral vascular resistances, respiratory and metabolic processes, extracellular volume and hematocrit have been studied in a total of 44 dogs before, during and after cross circulation. Free flow of blood from the carotid artery of one animal to the external jugular vein of the other animal was allowed for 60 minutes. The mean arterial pressure and cardiac output findings confirmed previously reported findings but were based on the results obtained from a larger number of animals. A significant decrease in the systolic, diastolic and mean pressures which followed the same pattern for both members of the pair were observed during the open shunt phase. During the 60 minutes of the post shunt period, the arterial pressures returned toward control levels. A slight but insignificant increase in pulmonary and peripheral vascular resistance occurred. Cross circulation does not alter significantly the oxygen consumption, carbon dioxide production, heat production, respiratory quotient and minute volume of either of the pair. A significant decrease in the extracellular space, blood and plasma volumes was observed consequent to cross circulation.
Oxidation to C14O2 and conversion to fatty acids of C14-glucose in livers of normal, fasted and x-irradiated rats
Authors: Coniglio John G. , Cate Deborah L. , Benson Bryant , Hudson Granville W.
Published: December 2017

Oxidation of glucose-1-C14 and of glucose-6-C14 to C14O2 was greater in slices and homogenates of livers of rats given 1000 r total-body x-irradiation and fasted 24–48 hours than in their nonirradiated fasted controls. The ratio: C14O2 from glucose-6-C14/C14O2 from glucose-1-C14 was not altered in homogenates either by fasting or by x-irradiation. In liver slices, the ratio was increased by fasting, per se, but was not affected by x-irradiation. In rats weighing 350–400 gm, hepatic conversion of glucose-1-C14 and of glucose-6-C14 to fatty acids was greater in the irradiated fasted animals than in nonirradiated fasted controls although the ratio: C14-fatty acids from glucose-6-C14/C14-fatty acids from glucose-1-C14 was not affected by irradiation. In rats weighing 160–200 gm, no difference in lipogenesis from either glucose-1-C14 or glucose-6-C14 was apparent between irradiated and control rats.
Changes in liver function and structure due to experimental passive congestion under controlled hepatic vein pressures
Authors: Brauer R. W. , Holloway R. J. , Leong G. F.
Published: December 2017

The effect of various hepatic vein pressures on hepatic hemodynamics, on fluid shifts within the liver, and on certain indices of liver function were studied in the isolated rat liver preparation. In general, venous pressures are scarcely perceived by the hepatic parenchyma unless they exceed the hydrostatic pressures acting at the liver surface, more particularly at the hilum of the liver. Venous pressures exceeding this value appear to distend the liver vasculature so that it acts like a system of rigid conduits; there is great expansion of the sodium space and of the colloid distribution spaces, and some evidence of partial sequestration of blood in the congested liver. All these changes impair oxygen supply to the tissue. To a lesser extent they interfere with the transfer of other substances from blood to parenchyma, and place considerable stress upon the mechanical framework of the liver. The resulting strain in turn tends to limit the extent of intrahepatic changes in passive congestion, and possibly the rate of fluid leakage from blood via parenchyma to transudate at the liver surface.
Responses to phenethylamines and nicotine and histology of turtle atria
Authors: Dimond Sister Marie Therese
Published: December 2017

Epinephrine (E), norepinephrine (NE), tyramine (T) and nicotine were tested at various dosage levels on different atrial regions of the heart of the eastern painted turtle, Chrysemys picta picta (Schneider), and the median effective dose determined. The three phenethylamines acted according to the following pattern in their effect on rate increase, amplitude increase, and inhibition of tonus waves: E > NE > T, except for amplitude increase in the left atrium and tonus wave inhibition in both atria, where E and NE were equal. The right sino-atrium and left atrium differed in sensitivity to the drugs. The various responses, including treppe, are consonant with the theory of the release from the tissues of a potentiating substance and a depressing substance. Histological stains for chromaffin tissue, a possible source of potentiating substance, were negative, but a differentially stained type of cardiac muscle, a possible conducting tissue, is present in regions of the sinus venosus and both atria and at the base of the interatrial septum.
An adrenergic basis for bulbar inhibition
Authors: Cranmer J. I. , Brann A. W. , Bach L. M. N.
Published: December 2017

Evidence has been obtained showing that intravenous infusion of Diebenzyline in cats anesthetized with Nembutal will consistently and completely abolish inhibition of the patellar reflex induced by direct stimulation of the bulbar reticular formation. The inhibition can always be restored by subsequent infusion of epinephrine. Parallel vasopressor effects can also be observed. Various techniques, including direct injection of Dibenzyline and epinephrine into the medulla through hollow electrodes, provided evidence that these drugs exerted depressant and enhancing effects, respectively, on the thresholds for bulbar inhibition. There appear to be regional differences in epinephrine sensitivity in the medulla. The area corresponding to the nucleus reticularis gigantocellularis appears to be more sensitive to epinephrine than surrounding reticular nuclei. The results suggest that locally released epinephrine activates the gigantocellularis nucleus which, in turn, develops a pattern of discharges leading to an inhibitory effect mediated by spinal projections. This mechanism may explain immobilization which frequently occurs in highly emotional situations.
Some local factors affecting iridic lipid infiltration in hypercholesteremic rabbits
Authors: Friedman Meyer , Byers Sanford O.
Published: December 2017

The influence of various factors affecting the deposition of lipid and cholesterol in the iris of rabbits fed cholesterol and cottonseed oil was studied. It was observéd that this deposition could be increased by the intraocular implantation of either normal aortic tissue or polyethylene discs. In an additional study, it was found that intermittent exposure of the eyes of cholesterol-fed rabbits to intense light also provoked an earlier and more intense iris deposition of lipid and cholesterol than was observed in the eyes of similarly fed rabbits kept either in absolute darkness or under ordinary laboratory conditions. It was postulated that the factor responsible for the greater iridic deposition observed in all these experimental animals was the iridic vasodilatation effected by these experimental measures.
Effect of diet on distribution of urea and electrolytes in kidneys of sheep
Authors: Schmidt-Nielsen Bodil , O'Dell Roberta
Published: December 2017

In sheep and other mammals on normal protein intake, the kidney urea concentration showed an increase from cortex to papilla, and the urine urea concentration was usually higher than in the tissue. In sheep on low-protein diet, the highest urea concentration was found in the inner stripe of the outer zone of the medulla, where it was 5–15 times the urine urea concentration. At the tip of the papilla, it was only slightly higher than in the urine. The electrolyte distribution in kidneys of sheep on normal and low protein diet differed in one important respect. In normal protein sheep, the electrolyte concentration in the papilla was usually higher than in the urine. In contrast, in low protein sheep, it was lower in all zones of the kidney than in the urine. However, because of the accumulated urea in the outer zone of the medulla, the osmotic concentration in this zone equaled the osmotic concentration of the urine.
Source and function of urinary ammonia in the alligator
Authors: Coulson Roland A. , Hernandez Thomas
Published: December 2017

The rate of renal deamination of 18 amino acids was determined by injecting them into alligators and measuring the ammonia excreted. Not only did glycine, alanine, glutamine and leucine account for nearly half of the plasma amino acids, they were also deaminated more rapidly than any of the others. In view of this it was concluded that these four amino acids are the natural precursors of urinary NH3 in the alligator. Increased NH3 and CO2 excretion following glycine injections resulted in increased renal reabsorption of Na and Cl when NaCl was injected and increased Na reabsorption when NaHCO3 or Na phosphate solutions were injected. The fact that excess NH4HCO3 excretion enhances salt reabsorption independent of plasma pH makes it probable that the excretion of N is the chief function of the ammonia mechanism and that salt conservation is incidental. Insulin decreased the plasma amino acid level and drastically reduced the NH3 excretion. With the decrease in ammonia, NaCl and NaHCO3 were excreted in increased amounts.
Possible associations of dietary residues with growth of the large gut
Authors: Moinuddin Jessie Fischer , Lee Helen Wing-Tsit
Published: December 2017

Diets containing 67% cornstarch, or 42% cornstarch plus 25% lactose, agar, cellulose or raw potato starch, were fed to rats. Dimensions of the cecum and colon plus rectum and many characteristics of large intestinal and fecal residues were recorded. Possible relationships of these dimensions and characteristics to the diet-produced differences in weights of the cleaned cecum and colon plus rectum were sought by correlation and covariance methods. The following possible associations were found. The cecal dry weight was possibly associated with the length and maximum width of the cecum (containing its fill) and also with the weights of cecal fill. The dry weight and the weight:length ratio of the colon plus rectum were possibly associated with the fresh weight/fecal pellet and with other weights and dimensions of colonic fill and of feces. Despite these findings, in most cases we could not decide what relationship the residues might have to large intestinal growth and function. Nor could we decide how certain diets stimulate cecal or colonic growth.
Some species differences in the intrinsic factor stimulation of B12 uptake by small intestine in vitro
Authors: Wilson T. Hastings , Strauss Elliott W.
Published: December 2017

Sacs of everted small intestine from a variety of animals were incubated in bicarbonate-saline containing vitamin B12 with and without intrinsic factor (IF). B12 uptake by rat intestine was stimulated only by its own intrinsic factor. Guinea pig ileum responded to all intrinsic factors tested (guinea pig, rat, hog, hamster, human being and rabbit). The intestines of hamster and rabbit were intermediate in specificity, responding to some, but not all, of the IF preparations. Species differences occur in both the intestine and intrinsic factor preparations. The guinea pig ileum was suggested as a possible assay for both hog and human IF.
Mechanisms of immediate respiratory responses to chlorpromazine
Authors: Schopp Robert T.
Published: December 2017

Following the intravenous injection of chlorpromazine (5 mg/kg) in dogs anesthetized with Pentothal-chloralose, respiratory inhibition occurs followed by stimulation. A fall in arterial blood pressure accompanies the respiratory responses. The evidence indicates that a reflex is involved with receptors for the inhibitory response and at least the major portion of the stimulation located in the thorax with afferent pathways in the vagus nerves. The inhibition and stimulation persist when the arterial blood pressure is compensated. The inhibition and most of the stimulation are eliminated by vagotomy. It is suggested that the respiratory responses are primarily due to the activation of chemical-sensitive receptors. A portion of the stimulation may be related to the fall in blood pressure.
Myocardial extraction of Rb86 in the rabbit
Authors: Mack Robert E. , Nolting David D. , Hogancamp Charles E. , Bing Richard J.
Published: December 2017

An investigation of the myocardial extraction of Rb86 was carried out using the Langendorff preparation in the isolated rabbit heart. Extraction was found to be related exponentially to both the rate of flow and the length of time of the flow. In the determination of coronary blood flow based upon the myocardial uptake of Rb86, an average value for myocardial extraction must be assumed in order to avoid coronary sinus catheterization. The data in these rabbit experiments suggest that when coronary blood flow is increased or decreased 50% the error which results from assuming a constant value for myocardial extraction is of the order of 20%.
Glycogen and phosphorus in skeletal muscle of the lizard, Anolis cristatellus
Authors: Rodriguez-Trias Helen
Published: December 2017

Total and trichloroacetic acid extractable glycogen, total and acid soluble phosphorus were determined in two types of skeletal muscle of the lizard, Anolis cristatellus. Glycogen was assayed by the anthrone method and phosphorus by a modification of the Fiske and SubbaRow method. The total and trichloroacetic acid soluble glycogen was found to be higher in concentration in mixed muscles than in agranular ones, and the difference is statistically significant. The concentration of total and acid soluble phosphorus was also found to be higher in mixed muscles than in agranular ones, but the differences are not statistically significant. Whether the difference in the glycogen concentration between the two types of muscle is related to functional differences is still unknown.
Neural limitations of visual excitability: II. Retrochiasmal interaction
Authors: Wagman I. H. , Battersby W. S.
Published: December 2017

Binocular visual excitability changes were obtained from two trained observers by presenting a "conditioning" flash of light to one eye and a brief "test" flash to a homologous retinal position in the other. Interval between flashes ranged from –200 msec. (test flash preceding conditioning) to +600 msec. (test following onset of conditioning flash). Results showed that threshold rose when test preceded conditioning flash, reaching a maximum increment of 0.5 log ml at –25 msec. separation. When test was superimposed upon conditioning flash in time, threshold dropped sharply to reach a relatively constant but elevated value for the duration of the conditioning flash. No excitability changes were obtained, however, if the test and conditioning flashes were displaced so as to stimulate adjacent rather than "corresponding" retinal points. These findings indicate that central (retrochiasmal) factors can influence visual sensitivity, the magnitude of this influence varying with the spatial and the temporal relations between successive light flashes. This conclusion is compatible with recent electrophysiological data on excitability changes in the cerebral visual system.
Plasma corticosterone and adrenal ascorbic acid levels in adeno- and neurohypophysectomized rats given epinephrine postoperatively
Authors: Fisher J. D. , De Salva S. J.
Published: December 2017

Studies in female Sprague-Dawley rats have shown that 24 hours after surgery, total and adenohypophysectomy blocks increased plasma corticosterone and adrenal ascorbic acid depletion responses following epinephrine. Neurohypophysectomy did not inhibit the increased plasma corticosterone changes, but did block adrenal ascorbic acid depletion response following epinephrine. In the intact animals, epinephrine elicited the elevation of plasma corticosterone and adrenal ascorbic acid depletion.
Mechanism controlling entry of ova into rabbit uterus
Authors: Black D. L. , Asdell S. A.
Published: December 2017

A mechanism is present at the lower end of the rabbit oviduct which prevents the entry of ova into the uterus until the reproductive organs come under the influence of progesterone. In normal rabbits, distention of the oviduct caused by ligating the infundibular end, recedes between the 60th and 72nd hour post coitum. Estrogen injections prolong distention. Progesterone does not markedly speed up ovum transport and is effective only when it can overcome the effect of endogenous estrogen. Circular muscle activity was recorded at three levels of the oviduct. Activity in the ovarian end greatly exceeded that in the lower sections of the tube. At the uterine end activity was very slight or not present at all. Several attempts to demonstrate the presence of edema in the tubo-uterine junction were unsuccessful.
Long-term effects of diencephalic lesions on the ovary of the hen
Authors: Ralph C. L. , Fraps R. M.
Published: December 2017

Small lesions produced electrolytically in the median diencephalon of actively ovulating hens caused most of them to cease ovulation regardless of the site of lesions. The duration of the nonovulating period thus induced, however, tended to vary with position of the lesions. When in the preoptic hypothalamus, supraoptico-hypophyseal tract, or dorsocaudal thalamus, the mean periods of interruption were about twice that found when lesions were in the central diencephalon. Considerable variability was encountered, however. A possible explanation is offered for the differing rates of functional recovery which occur following the placement of lesions.
Effect of epinephrine on relation of acetylcholine to intestinal tonus
Authors: Tidball M. E.
Published: December 2017

Isolated segments of rabbit intestine were subjected to epinephrine in order to depress intestinal tonus. The acetylcholine concentration of the fluid surrounding the rabbit intestine was assayed on guinea pig ileum which had been pretreated with dichlorophenyl-2-isopropylaminoethanol which blocked the action of epinephrine on the ileum without altering the response to acetylcholine. In the 21 tests performed, acetylcholine concentration of the rabbit bath fluid was found to be directly proportional to intestinal tonus. This indicates that epinephrine influences intestinal tonus indirectly through its ability to alter acetylcholine metabolism. Statistical tests showed that these data could be combined with data from earlier experiments in which it was found that acetylcholine concentration is directly proportional to the tonus of spontaneously contracting isolated intestinal segments. It is therefore concluded that both under control conditions and in the presence of epinephrine, acetylcholine is the principal factor responsible for the regulation of tonus in isolated intestinal segments.
Interruption of the enterohepatic circulation and its effect on rat bile
Authors: Light Harry G. , Witmer C. , Vars H. M.
Published: December 2017

The effects of anesthesia, trauma and starvation upon the composition of bile collected immediately after operation were obviated by preparing an external enterohepatic circulatory system. After 4–7 days the cannulas were separated, bile collected in various fractions of the 1st day and analyzed for total cholic acid and cholesterol. Cholate concentration in the first 3-hour collection was high, approximately 47% of the first day's total output. Cholate concentration in hours 3–6 was about 15% of the initial period, then gradually increased to a plateau on day 3 or 4. There was little change in cholesterol concentration in the 1st day's samples, but it about doubled by day 3 or 4. Cholic acid/cholesterol ratio rapidly decreased during the first 6 hours and remained low throughout the 1st day. The initial changes occurred earlier than observed by Eriksson in samples collected immediately following operation. Changes of bile composition following interruption of the enterohepatic circulation must be considered in evaluating bile excretion studies.
Change in regulation of serum cholesterol induced by homologous and heterologous desoxyribonucleic acid
Authors: Savitsky J. Philip
Published: December 2017

Desoxyribonucleic acid (DNA) was carefully prepared in a highly purified, undenatured form from beef brain, beef liver and rabbit liver. One milligram of DNA was injected into each rabbit. Over a period of 2–6 months the mean serum cholesterol declined significantly below normal control levels. This change in the mean largely reflected the decline in cholesterol levels of those animals with high normal values. Concomitantly, the standard deviation and coefficient of variation of the serum cholesterol levels decreased to one-third the normal control values. The serum phospholipids and neutral fat showed similar lower mean levels and decreasing variation. Evidence is presented that the injected DNA is the active material producing these changes. Homologous and heterologous DNA were equally effective. An hypothesis is suggested relating the DNA-induced changes in the serum lipids to polygenic regulatory systems.
Effects of atropine on synthesis and secretion of pepsinogen in the rat
Authors: Hirschowitz Basil I. , O'Leary D. K. , Marks I. N.
Published: December 2017

Simultaneous measurements of gastric juice pepsin and stomach mucosal pepsinogen were made in groups of pylorus-ligated rats at intervals from 2 to 24 hours to examine the effects of atropine sulfate (20 mg/100 gm/8 hrs.) on pepsinogen secretion and synthesis. Animals given subcutaneous injections of water served as controls. Atropine caused a marked reduction in pepsinogen secretion and a concomitant accumulation of pepsinogen in the mucosa which increased with time to a plateau; pylorus ligation had the opposite effect, indicating that atropine effected the reduction in secretion of pepsinogen by blocking the release of pepsinogen from peptic cells. In untreated rats the hematocrit increased proportionately to presumed body water loss, but in the atropine-treated rats the hematocrit failed to increase to the same degree for equivalent body water loss. Indirect evidence is presented to suggest that the rate of water secretion may be one of the rate-limiting factors in pepsinogen secretion. Although synthesis of pepsinogen can proceed without secretion, correlation of the rates of synthesis with those of secretion suggested that the rate of synthesis could be increased by an increased rate of secretion.
Effect of atropine and of chronic A-V block on coronary blood flow in the dog
Authors: Scott J. C. , Balourdas T. A.
Published: December 2017

Coronary sinus blood flow was measured by the nitrous oxide desaturation method in mongrel dogs under several experimental conditions. Observations were made in each of these conditions before and after the administration of atropine. Intravenous atropine markedly increases coronary sinus blood flow and heart rate in normal dogs but has no effect following acute bilateral cervical vagotomy. Atropine increases the coronary sinus blood flow to a moderate degree with no change in ventricular rate, in chronic A-V block dogs. Chronic A-V block does not change coronary sinus blood flow but increases calculated left ventricular efficiency. Chronic A-V does not produce congestive heart failure under conditions of somewhat restricted physical activity. Effects of atropine on coronary sinus flow are believed to be mediated through vagal fibers controlling heart rate. In the case of A-V block animals where the ventricular rate is constant the increased coronary flow may be due in part to the increase in atrial rate.
Effect of mercuric chloride on some kidney enzymes in chow-fed and sucrose-fed rats
Authors: Shore V. , Shore B.
Published: December 2017

Rats given a diet of sucrose and vitamins for 3 weeks or more develop a tolerance to mercuric chloride greater than that of chow-fed rats. Comparison of several enzyme systems (tricarboxylic acid cycle, succinic dehydrogenase, cytochrome oxidase, α-ketoglutarate dehydrogenase, alkaline phosphatase, cathepsins and ß-glucuronidase) in chow-fed and sucrose-fed rats indicated no significant differences in activities. After 3 mg HgCl2/kg i.v., notable differences in the extent of inhibition of tricarboxylic acid enzyme systems were observed. Twenty-four hours after such an injection, kidneys of chow-fed rats were seriously hampered in their ability to perform biological energy transformations. Oxidation and phosphorylation by sucrose-fed rat kidneys were considerably less inhibited.
Stimulation of C14-histidine incorporation into protein of isolated diaphragm by nonutilized sugars
Authors: Wool Ira G.
Published: December 2017

The effect of various sugars on protein synthesis was studied by measuring the incorporation of C14-histidine into the protein of the isolated diaphragm. In diaphragms from rats fasted 48 hours, histidine-2-C14 incorporation into muscle protein is directly proportional to the glucose concentration in the incubation medium over the range 0–600 mg %. The ability of other sugars to reproduce this effect of glucose on C14-histidine incorporation into diaphragm protein was tested. The following were found to be as effective as glucose: d-mannose; d-xylose; d-ribose; l-sorbose. The following were without effect: d-galactose; d-fructose; 3-methyl glucose; d-arabinose; l-arabinose; l-xylose. Only 2-deoxy-d-glucose was inhibitory. The results indicate that sugars not appreciably utilized by muscle (i.e. d-xylose, d-ribose and l-sorbose) can increase protein synthesis. The findings do not support the theory that the positive influence of carbohydrate on protein metabolism derives solely from its ability to increase the energy available for protein synthesis.
Red cell repopulation in irradiated mice treated with plethoric homologous bone marrow
Authors: Goodman Joan Wright , Owen Ray D.
Published: December 2017

Marrow from normal homologous donors injected into heavily irradiated recipients results in a fast and permanent replacement of host- by homologous donor-type erythrocytes. Plethoric marrow, produced by artificial polycythemia, was capable of red cell repopulation of an irradiated homologous host. Repopulation was slower from plethoric than from normal marrow but reached 100% donor type and remained permanently at that level in all chimeras tested. There was a large decrease in hematocrit within the first 2 weeks after X-ray and bone marrow treatment in some, but not all, homologous combinations tested. In the combination studied most extensively, lethally irradiated (C3H x 101)F1 receiving (C57L x A)F1 marrow, the early anemia was considerably ameliorated by the use of plethoric in place of normal marrow. Possible mechanisms for these effects are discussed. It is suggested that plethoric marrow has a potential greater than that of normal marrow for producing blood platelets and can rapidly effect repair of capillary walls and thus reduce early red cell loss.
Coexisting mechanical and electrical alternation in drug-induced pulsus alternans in dogs
Authors: Ellis Charles H.
Published: December 2017

Alternation can be evoked in the dog heart by i.v. injections of moderately large doses of methoxamine hydrochloride. In a study of responses to 123 doses in 50 dogs, ‘true’ pulsus alternans without measurable electrical alternation occurred most frequently. Coexisting electrical alternation was present in only one-fourth of the cases in which mechanical alternans was induced by the drug. Only once did electrical alternans develop in the absence of mechanical alternans. Electrical alternation, when present, was usually limited to changes in amplitude of T; more rarely, of R. The usual pattern was one in which the electrogram associated with the weaker ventricular contraction showed greater negativity than that for the stronger heart beat. The mechanism of mechanical alternans is probably independent from that of electrical alternation. When T wave changes are the only electrical evidence of alternation, beat-to-beat changes in time of onset of repolarization in localized areas of the myocardium are thought to be involved. Changes in R probably indicate that conductional delays have also contributed, but since alternation in R was rare in drug-induced alternans, it is doubtful that delayed conduction is of great general significance.
Effect of antecedent diet and of cortisone treatment on cholesterol-4-C14 metabolism in rabbits
Authors: Dury Abraham , Swell Leon
Published: December 2017

Metabolic behavior of a test meal containing cholesterol-4-C14 (10 µc C14; 1 gm cholesterol) was observed through 2 days in rabbits previously fed for 35 days a normal diet ( A), and high-cholesterol diet alone ( B) and concurrent cortisone treatment ( C). In the early postprandial period the relative incorporation of cholesterol-4-C14 in the plasma-free and ester cholesterol differed markedly in the three groups. In group C the activity in the plasma cholesterol fractions increased precipitously and maxima specific activities were reached with the 24-hour blood sample while in groups A and B activity in the plasma increased much slower. C14-cholesterol was not incorporated in aorta ester cholesterol of groups A and C 2 days following the labeled cholesterol meal while in aortas of group B a definite amount of ester cholesterol-4-C14 was found. Free and ester cholesterol-C14 quantities in the liver, the plasma and the ileum were greater in group B than that present in respective tissues of group A. On the other hand, larger quantities of liver ester cholesterol-C14 and plasma free cholesterol-C14 were present in group C than in B. The results indicated that metabolic handling of a cholesterol meal was influenced by type of previous diet regimen and that cortisone treatment modified dietary cholesterol behavior in the cholesterol-fed rabbit.
Some effects of fasting on rats fed a choline-deficient diet
Authors: Rees E. Douglas , Winternitz William W. , Lattanzi William F.
Published: December 2017

The blood ketone body concentrations of fasted and nonfasted rats fed a diet deficient in choline were determined and found to be similar to the concentrations obtained from a control group fed the same diet supplemented with choline. However, the animals on the choline-deficient diet had an 18–20% greater mean liver mass, and this could account for the failure to demonstrate the depressed level of blood ketone bodies which was anticipated on the basis of previous in vitro studies. Other possible explanations of this discrepancy are discussed. Despite a high hepatic fat content, the choline-deficient group had a normal concentration of liver glycogen. The nonfasting blood glucose concentration of the choline-deficient group (91.5 ± 5 mg %) was lower than that of the control group (102 ± 3 mg %). After 24 hours of fasting, the values were 52 ± 3 mg % and 61 ± 5 mg % for the choline-deficient and control group, respectively. The 72-hour fasting values were 43 ± 2 mg %, and 49 ± 2 mg %, respectively. Data showing the effect of diet composition on ketonemia, liver glycogen and blood glucose are presented and are in accord with previous studies.
Effect of prolonged cold exposure on the glycolytic enzymes of liver and muscle
Authors: Hannon John P. , Vaughan David A.
Published: December 2017

Liver and muscle tissue from male Sprague-Dawley rats, exposed to 5 ± 1°C for 3–4 weeks, were assayed for the activities of selected glycolytic enzymes. When compared to control animals maintained at 25 ± 1°C, the cold-exposed animals showed an increase in liver glucose-6-phosphatase, an increase in liver and muscle glucokinase, a decrease in glucose-6-phosphate and 6-phosphogluconic dehydrogenase in both liver and muscle, and an increase in the rate of pyruvate formation from 3-phosphoglycerate in liver tissue. Assays of liver and muscle phosphoglucomutase, total liver and muscle phosphorylase and phosphorylase a and b in muscle failed to show any cold effect. The results indicate the cold-exposed rat has the enzyme capacities for: an increased utilization of free glucose, an increased glycogenolysis either to free glucose to pyruvate and an increased gluconeogenesis. They also indicate a decreased hexose monophosphate shunt activity. Little evidence could be found to indicate an epinephrine-induced activation of phosphorylase in the cold-exposed animals.
Hibernation, temperature and rates of oxidative phosphorylation by heart mitochondria
Authors: South Frank E.
Published: December 2017

The effect of temperature on rates of oxidative phosphorylation (pyruvate substrate) by heart mitochondria obtained from hibernating hamsters, control hamsters and rats was studied. Apparent energies of activation ( Ea) determined between 5° and 24°C were, respectively, 20.4, 20.8 and 28.3 Kcal. for the rates of oxygen consumption and 20.6, 21.4 and 29.5 Kcal. for the rates of phosphorylation. The difference between the rats and either group of hamsters were significant statistically. The slope of the regression line fitted to the data obtained from hibernating animals did not differ significantly from that of the control hamsters. However, a parallel vertical displacement of the lines indicated a probable increase in these oxidative enzymes upon preparation for, or during, hibernation. No significant alterations in the efficiency of oxidative phosphorylation with variations in the incubation temperature were noted in any of the preparations.
Potentiation and hysteresis induced by stretch and subsequent release of papillary muscle of the dog
Authors: Walker Sheppard M.
Published: December 2017

Isolated papillary muscle of the dog was placed in an oxygenated Ringer's solution bath maintained at 36°C, and isometric recordings of resting tension and developed tension were obtained for stretched muscle and for subsequently released muscle. The hysteresis loop produced by stretch and subsequent release of resting papillary muscle resembles closely the hysteresis loop obtained by stretch and subsequent release of skeletal muscle. This means that the length-resting tension curve obtained by release of papillary muscle falls considerably below the similar curve obtained by stretch of this muscle. A comparison of the length-developed tension curves for stretched and subsequently released papillary muscle shows that developed tension is potentiated in released muscle at all observed lengths, the range of length being 100–148% of equilibrium length. The average of maximum developed tension was 164.7 gm/cm2 in 20 experiments with stretched papillary muscles and 228.8 gm/cm2 in 20 experiments with the same muscles released immediately after stretch.
Inorganic sulfate and thiosulfate: transport and competition in renal tubules of the dog
Authors: Berglund Fredrik , Helander Carl-Gustaf , Howe Robert B.
Published: December 2017

In the renal tubules of the dog sulfate and thiosulfate are reabsorbed, and thiosulfate is secreted. Secretion of thiosulfate is maximally inhibited by carinamide at plasma levels as low as 20 µg/ml; sulfate transport is not affected. Sulfate and thiosulfate mutually inhibit each other's reabsorption. Simultaneous measurement of sulfate and thiosulfate reabsorption at varying concentration ratios of the two ions indicates that this mutual inhibition is of ‘competitive’ type. At normal sulfate levels, thiosulfate reabsorption increases in a semilogarithmic fashion with rising thiosulfate levels. By using a Lineweaver-Burk plot, thiosulfate Tm (transfer maximum) was estimated at 0.65 of sulfate Tm. Assuming this ratio to be identical with the ratio between the equilibrium constants for S2O3-carrier and SO4-carrier, theoretical reabsorption rates were calculated for thiosulfate and sulfate in each other's presence. The urinary excretion of thiosulfate at low plasma levels indicates that the site of tubular secretion is not distal to the site of reabsorption. Thiosulfate secretion is inhibited by sulfate. A common carrier is suggested for reabsorption of sulfate and thiosulfate and secretion of thiosulfate.
Effects of d-tubocurarine on the submandibular salivary gland
Authors: Elwell Leonard H.
Published: December 2017

First injections of d-tubocurarine in doses of 0.3–1.5 mg (2–10 u) into the arterial blood supply, limited to acutely denervated submandibular salivary glands of anesthetized dogs, resulted in a prompt and large transient increase in the blood flow through the gland and, when the dose was sufficient, initiation of a transient secretion of saliva. Both the vascular and secretory responses diminished progressively with repeated administrations of the drug. Preadministration of diphen-hydramine (Benadryl) reduced the vascular and secretory responses to ‘first’ injections of d-tubocurarine, suggesting that histamine released from the glandular tissue might be an intermediary for the observed effects. Increased levels of histamine in the effluent blood plasma after administration of d-tubocurarine, as determined by biological assay, supported this role for histamine. Systemic administration of d-tubocurarine, with the gland normally innervated, but vascularly isolated and perfused, yielded no evidence for a possible centrally initiated vasodilatation and salivation.
Effect of an insulin infusion on hepatic output of glucose
Authors: Fine Melwyn B. , Williams Robert H.
Published: December 2017

Catheters were placed in the hepatic vein and portal vein of normal dogs and were maintained for varying periods of time. With these animals in an unanesthetized state and recovered from the acute effects of the catheter implantations, small amounts of insulin were slowly infused into the portal vein and the hepatic output of glucose was determined. It was concluded that under the experimental conditions insulin did not significantly depress the hepatic output of glucose but that it did inhibit the hepatic response to hypoglycemia. The hepatic glucose output during the infusion was similar to the control values but there was a marked rise in glucose output following the cessation of the infusion.
Inhibition of spermatozoan metabolism by pCO2, pH, K ion and antibacterial compounds
Authors: Salisbury G. W. , VanDemark N. L. , Lodge J. R. , Cragle R. G.
Published: December 2017

The effect of increasing partial pressure of carbon dioxide (pCO2) on fructose disappearance, lactate accumulation, and CO2 evolution from bicarbonate, after correction for retention, of bovine spermatozoa was studied. In a diluent composed primarily of the sodium salts of citrate and bicarbonate, the metabolism was maximum with a gas phase of N2 and decreased with each increase in pCO2 to a minimum, about 10% of that under N2, with a pCO2 of 100%. The inhibition was reversible upon aeration of the sperm cells. After inhibition under 100% CO2 for 24 hours, the recovery of glycolytic function under 5% CO2, 95% N2 was nearly complete during an additional 4-hour period. In the sodium diluent all the hexose which disappeared was recovered as lactate. However, when the sodium was replaced by potassium, hexose disappearance was inhibited only slightly by CO2 and very little of the hexose was converted to lactate. Hexose disappearance was depressed by sulfanilamide at low pCO2 and acid end-products other than lactic may be formed.
Monosynaptic activation of different portions of the motor neuron membrane
Authors: Fadiga Ettore , Brookhart John M.
Published: December 2017

Using isolated frog spinal cords, treated with pentobarbital to silence internuncial discharge, intracellular recordings from motor neurons reveal differences in dendritically initiated EPSP evoked by dorsal root stimulation and somatically initiated EPSP evoked by lateral column stimulation. Under these conditions, dorsal root EPSP never reached motor neuron threshold whereas threshold was easily reached by lateral column EPSP. EPSP's initiated by dorsal root volleys were slower in their time course and smaller in their amplitude than those initiated by lateral column volleys. EPSP's initiated by lateral column volleys reduced the amplitude of antidromic spikes, while those produced by dorsal root stimulation did not. Lateral column induced EPSP was also capable of reducing the amplitude of orthodromic spikes. Some observations on duration of transmitter action are reported. It is concluded that dendritic excitation following a dorsal root volley influences the level of polarization of the cell body by electrotonic propagation of the resulting EPSP.
Intragastric pressures in pylorus-ligated mice
Authors: McArthur W. , Michel A.
Published: December 2017

The relationship between circulation, intragastric pressure and ulcer formation, was investigated in the pylorus-ligated mouse. Eight hours after pyloric ligation, the animals were etherized and intragastric pressures measured. The stomach contents were aspirated and determined. The stomach was opened and number and location of ulcers noted. In another series of animals, India ink was injected into the stomach through the aorta. Injected stomachs of normal and pylorus-ligated mice were cleared with the Spalteholtz method and examined with a dissecting microscope. In the stomachs of normal and of pylorus-ligated mice, areas of lesser vascularity were seen, and in these areas most ulcers appeared to occur.
Effect of parathyroidectomy on content and availability of skeletal sodium in the rat
Authors: Nichols George , Nichols Nancy
Published: December 2017

The effect of parathyroidectomy on the composition of plasma and bone has been examined in rats with and without sodium depletion. Parathyroidectomy caused a marked fall in calcium and a slight decrease in chloride in the plasma and a 7.9% increase in bone mineral sodium concentration. Sodium depletion by intraperitoneal dialysis of normal animals lowered bone mineral sodium 4% while plasma sodium and pH remained at almost normal levels. In contrast, sodium depletion following parathyroidectomy failed to lower bone sodium significantly but produced a significant acidosis and a slight decrease in plasma sodium. These findings suggest that the ability of bone to release sodium ions to protect extracellular fluid pH in acute sodium depletion is dependent on the presence of the parathyroid glands. Possible mechanisms by which parathyroid activity might influence bone sodium metabolism by changes in bone cell metabolism, changes in the Na:Ca ratio of extracellular fluid, or actual bone destruction are discussed.
Effects of intravenous steroids on seminal vesicle contractions of castrated rats
Authors: Grunt Jerome A. , Walker Joseph E. , Higgins James T.
Published: December 2017

Young adult castrated male rats were used in a study of the effects of four intravenous steroids on seminal vesicle contractions. One lobe of each animal's seminal vesicle was exteriorized and recordings of the rhythmic contractions were made with a muscle lever attached to a kymograph. Following two periods of control recordings, each of the animals was injected intravenously with either 300 µg water soluble testosterone, 200 µg water-soluble estrogen (Premarin), 300 µg hydrocortisone hemisuccinate or 300 µg methyl prednisolone sodium succinate. The administration of androgen was followed by an inhibition of the frequency of contraction in 8 of the 11 animals. Four of the sixteen animals injected with intravenous estrogen showed a decrease in frequency of contractions. There was no seminal vesicle slowing following administration of either corticoid. An intravenous technique here described, allowed the administration of steroid at any time during the experiment without interrupting the preparation.