bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of chlortetracycline and neomycin on digestion and absorption of fat in rats
Authors: Krondl A. , Vokáč V. , Vavřínková H.
Published: December 2017

Effects of chlortetracycline (CTC) and neomycin on the rate of lipolysis and alimentary lipemia in rats, after the introduction of 1 ml of olive oil or a suspension of 1/10 of the ld50 doses of antibiotics in oil, were determined after 1 and 3 hr. Presence of CTC or neomycin did not affect the rate of gastric emptying. A similar finding was obtained concerning the amount of fat left in the intestine after these periods. In the presence of CTC the lipolysis was significantly inhibited after 1 as well as after 3 hr; alimentary lipemia was slowed down in the 1st hr, and after 3 hr a return to normal levels was achieved. Administration of neomycin did not influence the rate of lipolysis, but was followed by a lower level of alimentary lipemia not only after 1 hr but also after 3 hr.
Effect of acetoacetate on blood coagulation in rabbits and its prevention
Authors: Nath M. C. , Brahmankar D. M.
Published: December 2017

The effect of Na-acetoacetate injections on blood coagulation factors was studied. No change in blood coagulation factors occurred in 4 weeks, but continued treatment of acetoacetate for 8 weeks was found to cause hastening of blood coagulation. The hydrolyzed product of glucose cycloacetoacetate was found to prevent the acceleration of blood coagulation in acetoacetate-treated animals.
Experimental evaluation of a pulse contour method for calculation of cardiac output
Authors: Bernstein Eugene F. , Evans Robert L.
Published: December 2017

A method of estimating cardiac output which depends on the analysis of a single propagated pressure wave and the relationship between pressure change and velocity change: Δ p = ρ c0 Δ v, has been evaluated experimentally in 84 almost simultaneous comparisons with dye dilution method measurements and 22 almost simultaneous comparisons with direct Fick measurements. A deviation of 13.4 ± 22.9% between the dye and pulse contour measurements was observed. In comparison with direct Fick measurements, the deviation was 19.1 ± 33.0%. The ability of this pulse contour method to follow changes in cardiac output was better than its ability to estimate absolute output, as indicated by these deviations. The usefulness of this pulse contour technique in estimating cardiac output in clinical and laboratory situations, with a beat-to-beat indication of changes in output, is discussed. In general, this method appears to have a useful degree of accuracy and offers a relatively simple approach to an important problem.
Experimental biliary obstruction: effect of Thorotrast on lymph and serum bilirubin levels
Authors: Dumont Allan E. , Stertzer Simon H. , Mulholland John H.
Published: December 2017

Conversion of heme to bilirubin is believed to occur in the cells of the reticuloendothelial system (RES). Use of RES blocking agents in experiments designed to confirm this hypothesis has resulted in data that are equivocal. Determination of bilirubin in thoracic duct lymph provides a more sensitive guide to bilirubin production, in the presence of extrahepatic biliary obstruction, than studies of serum bilirubin alone. In the present report the effect of Thorotrast on bilirubin levels in the thoracic duct lymph and sera has been determined in dogs with experimental biliary obstruction. The results indicate that Thorotrast stops the production of bilirubin and support the view that the normal site of bile pigment production is the RES.
Effect of unreabsorbed anions on proximal and distal transtubular potentials in rats
Authors: Clapp James R. , Rector Floyd C. , Seldin Donald W.
Published: December 2017

Proximal and distal transtubular potential differences (ET) were measured in Na-fed and Na-depleted rats given infusions of 5% glucose in water, 0.9 m NaCl, 0.5 m NaHCO3, 0.5 m Na2SO4, and 0.25 m Na4Fe(CN)6. Proximal ET was –23.8 ± 0.8 mv and was uninfluenced by intravenous infusions of various Na+ salts. Distal ET was –53.8 ± 1.9 mv and rose sharply with infusions of Na+ salts of nonreabsorbable anions; the maximum rise was –31 mv in salt-depleted rats given Na2SO4. The rise in distal ET associated with polyvalent anions was attributed to both higher cation concentrations and lower Cl– concentrations in distal tubular fluid produced by infusions of these salts. It was suggested that the rise in distal ET is responsible for the known augmentation of K+ and H+ excretion produced by these salts.
Body glucose as fuel in white rats exposed to cold: results with fasted rats
Authors: Depocas Florent
Published: December 2017

Concentration of glycogen in liver and muscle of warm- and cold-acclimated rats was measured during fasting at 30 or 6 C. The biokinetics of glucose were then studied by priming and continuous infusion with C14-labeled glucose in 24-hr-fasted rats exposed to 30, 18, and 6 C. In warm-acclimated rats at 18 and 6 C there were higher rates of turnover and oxidation of glucose than at 30 C and the ratio of rates of oxidation to turnover increased, but glucose concentration in plasma, volume of distribution of glucose, and proportion of respiratory CO2 derived from glucose remained constant in the three environments. Cold-acclimated rats at 6 C had higher values of glucose concentration in plasma, of volume of distribution of glucose, and a slightly higher rate of turnover of glucose than warm-acclimated rats at 6 C. Gluconeogenesis thus can satisfy the elevated glucose requirement in the cold, and the fasted rat increases its heat production by an increase in glucose oxidation proportionate to the increase in energy metabolism as does the nonfasted animal.
Influence of connective tissue on swelling exhibited by muscles in vitro
Authors: Calhoon Thomas B. , Gadsden Richard H.
Published: December 2017

Analysis of rat skeletal muscle was made before and after immersion in a slightly hypo-osmotic solution. Similar studies were made on pieces of subcutaneous connective tissue. Total sodium, potassium, chloride, nitrogen, water, and weight were determined. The amount of connective tissue space within the whole muscle was estimated by determining thiocyanate space. From these studies calculations were made to determine the contribution of connective tissue within the whole muscle to electrolyte and water shifts exhibited by the whole muscle on immersion in a solution. It was found that almost all weight and water gained by whole muscle could be attributed to its contained connective tissue. However, muscle cells did exhibit an intracellular dilution because of a slight inward movement of water, a loss of cation and of cellular protein. Connective tissue itself appeared to be only diluted on immersion. The cause of this dilution is discussed.
Myofibrillar adenosine triphosphatase activity in congestive heart failure
Authors: Alpert Norman R. , Gordon Michael S.
Published: December 2017

Myofibrillar adenosine triphosphatase (ATPase) activity from seven failing and nine control hearts was studied. The failing hearts came from patients with a clinical and pathological diagnosis of congestive heart failure following benign essential hypertension. Normal hearts were obtained following traumatic death in otherwise normal subjects with no evidence of pathology. As the MgCl2 concentration was increased, the myofibrillar ATPase from the failing hearts exhibited a significantly lower rise in activity than that from the normal hearts. Increasing the substrate concentration to 5 mm adenosine triphosphate (ATP) increased the myofibrillar ATPase activity to an optimum of .95 µm/mg/15 min in the normal group and .69/µm/ mg/15 min in the failing group. Further increases in substrate concentration decreased the ATPase activity in both groups. It was concluded that myofibrils from a heart in congestive failure following benign essential hypertension hydrolyze ATP at a slower rate than those from normal hearts. Since myofibrillar ATPase activity and tension development go hand in hand, the decrease in ATPase activity in the failing heart may account for its inability to meet the work load imposed upon it. Thus these experiments offer evidence that a lesion in congestive heart failure may reside in the contractile protein itself.
Interactions of dietary sodium and potassium and their influence on energy metabolism
Authors: Smith J. D. , Meyer J. H.
Published: December 2017

A factorial design consisting of sodium (0.23 and 0.004%) superimposed on three levels of dietary potassium (0.002, 0.02, and 0.44%) was used. Energy utilization, body composition, activity, basal metabolism, body water compartments, and concentrations of sodium and potassium therein were studied in rats fed these rations. A large number of interactions between dietary Na and K were shown; the effect of either Na or K deficiency is dependent on the level of the other in the diet. Efficiency of energy utilization was lowered by a deficiency of either mineral. A slight reduction of basal energy metabolism was found in rats fed the low-sodium rations, whereas low-potassium rations had no significant effect. The decreased efficiency of energy utilization with low-sodium rations were attributed, at least partly, to increased activity. The multiple regression of basal metabolic rate on the concentrations of plasma Na, plasma K, intracellular Na, and intracellular K was found to be highly significant but no causative relationship is inferred.
A technique of studying salivary gland function
Authors: Henriques Basil L.
Published: December 2017

With the stop-flow method an approximate duct volume of 0.2 ml was determined for 12–15-kg dogs. Gross verification of the duct volume was made by comparing X-rayed glands injected with 0.2 ml BaSO4 with vinyl acetate models made of the entire acinar duct system. Microscopic comparison of the control and experimental specimens indicated damage, limited to the inner cells of the ducts. Functional tests were used to determine inhibition of transductal transport of Na+ by the duct cells. The Na+ and K+ concentration in saliva from both treated and untreated glands, collected utilizing the t0, time course, and stop-flow techniques, were assayed. The results showed that those duct cells previously treated with 0.05% solution of HgCl2 did not resorb Na+ or K+, nor did they store K+. Thus injection of HgCl2 solution does significantly inhibit the transductal transport mechanisms of the gland for Na+ and K+ and is well suited as an experimental technique in the study of the dog submaxillary salivary gland.
Central effect of epinephrine and norepinephrine on the palmar sweat index
Authors: Harrison J. , MacKinnon P. C. B.
Published: December 2017

An investigation is reported into the effect and site of action of systemically administered epinephrine and norepinephrine on numbers of active sweat glands in an area 4 mm sq over the central whorl of a middle finger pad (palmar sweat index). Both epinephrine and norepinephrine depressed the index. Although 20 mg phenoxybenzamine, an adrenergic blocking agent, had no effect itself on the index, it prevented the decrease which follows administration of epinephrine; this was probably due to a central effect, as experiments designed to eliminate local effects of the hormones on either the sweat glands themselves or their blood supply suggested that depression of the index was mediated through central nervous mechanisms.
Renal utilization and excretion of α-ketoglutarate in dog: effect of alkalosis
Authors: Cohen Julius J. , Wittmann Evelyn
Published: December 2017

Net renal transport (Tα-kg) and renal utilization (Qα-kg) of infused α-KG have been studied by renal clearance, stop-flow, and in vivo metabolic techniques in anesthetized (pentobarbital) dogs. The kidney is a major and specific site of α-KG dissimilation. Tα-kg sums brisk reabsorptive (–Tα-kg) and sluggish secretory (+Tα-kg) phenomena, localized to the proximal tubule. –Tα-kg is markedly decreased or reversed to +Tα-kg during either acute metabolic or respiratory alkalosis, indicating that extracellular fluid (ECF) pH and not intracellular fluid (ICF) pH is the common determinant. Changes in direction or magnitude of Tα-kg can occur independently of changes in Qα-kg, indicating that metabolism and transtubular transport of α-KG may be separate: Tα-kg changes spontaneously while Qα-kg remains relatively stable; probenecid reduces Qα-kg while not affecting Tα-kg; alkalosis causes parallel decreases in both Tα-kg and Qα-kg, but of differing magnitudes in each. It is suggested that alkalosis alters extrarenal metabolism resulting in accumulation of substrate ions in blood which compete with α-KG for transtubular transport, and independently, with α-KG for renal utilization.
Effect of fatty acid structure on esterification by the small intestine in vitro
Authors: Gelb Alvin M. , Kessler Jacques I.
Published: December 2017

The effect of chain length and degree of unsaturation of fatty acids (FA) on in vitro esterification by slices of hamster small intestine was observed in a medium containing C14-labeled FA. After incubation, lipids were extracted and separated and the radioactivity in the esterified lipids was measured. Comparative experiments, in which results were expressed as per cent of substrate esterified per 100 mg tissue, indicate that for saturated FA, maximal esterification occurred with myristic acid, 14 carbons. As chain length was either increased or decreased, percentage esterification decreased. FA with 8 carbons or less were only minimally esterified. Among 18-carbon FA, two unsaturated bonds significantly decreased percentage esterification, although one unsaturated bond did not. These results suggest that, at least in vitro, the small bowel esterifies FA at varying rates depending upon chain length and degree of unsaturation. These differences are in the same direction as differences in absorption and partition of FA in vivo previously reported by others.
Effect of 2-deoxyglucose on glucose turnover in normal and adrenalectomized dogs
Authors: Altszuler N. , Dunn A. , Steele R. , Bishop J. S. , De Bodo R. C.
Published: December 2017

C14 glucose, administered intravenously by a priming injection along with a continuous infusion, was used to measure the effects of 2-deoxyglucose infusion on glucose production and glucose uptake in unanesthetized normal or adrenalectomized dogs. Infusion of 2-deoxyglucose, 200 mg/kg in 30 min, produced a marked hyperglycemia in intact dogs. The development of the hyperglycemia was accompanied by an increase in glucose production. The over-all glucose uptake failed to increase above values in control state despite the hyperglycemia, thus reflecting a relative inhibition of glucose uptake. Infusion of 2-deoxyglucose did not diminish the effectiveness of administered insulin to increase glucose uptake, nor did it impair the disposition of a glucose load. Pretreatment of normal dogs with the adrenergic blocking agent, dihydroergotamine, prevented the usual hyperglycemia induced by 2-deoxyglucose. Similarly in the adrenalectomized dog, maintained on deoxycorticosterone acetate and cortisol, infusion of 2-deoxyglucose failed to produce hyperglycemia, or to increase glucose production, or alter glucose uptake. The possible role of epinephrine as the mediator of the effects of 2-deoxyglucose in the intact animal is discussed.
Effect of heparin on leukocyte response to hydrocortisone injections
Authors: Paluska Donald J. , Hamilton Lyle H.
Published: December 2017

A subcutaneous injection of heparin (100 IU and 500 IU/100 g body wt.) produced a panleukocytosis in rats. The lymphocyte response was greater with 500 than with 100 IU/100 g body wt. The leukocyte count returned toward control levels 8 hr after the injection. The magnitude of the leukocyte response to heparin was unaffected by the blood sampling site, the sex of the animal, or the preparation of heparin used to elicit the response. Hydrocortisone (3 mg/100 g body wt.) produced a lymphopenia 4 and 8 hr after its subcutaneous injection. It produced no significant change in the neutrophil count at either of these times. When the two drugs were given to rats simultaneously, heparin antagonized the effect of hydrocortisone on the lymphocyte count and hydrocortisone inhibited the effect of heparin on the neutrophil count.
Inhibition of endotoxin-induced pulmonary vasoconstriction in dogs by alpha-methyl dopa
Authors: Koehler J. Albrecht , Tsagaris Theofilos J. , Kuida Hiroshi , Hecht Hans H.
Published: December 2017

The demonstration in a previous study of the effectiveness of an antihistaminic drug in blocking some of the systemic but not the pulmonary vascular effects of endotoxin led to the study of the effect of an inhibitor of serotonin synthesis, alpha-methyl 3,4-dihydroxyphenylalanine (α-m dopa). One group of seven dogs was pretreated with a single dose of 250 mg, and a second group of six animals with three doses of 250 mg, each given at 10-min intervals. Results in these two groups were compared with those in six control animals. Purified E. coli endotoxin, 1 mg/kg, was administered intravenously in all 19 experiments. Intravenous administration of α-m dopa alone had no effect on measured physiologic parameters. Compared with the endotoxin response in control animals, pretreatment with either dose level appeared to have no effect on the magnitude or duration of systemic arterial hypotension, portal venous hypertension, or drop in cardiac output. However, pretreatment with 250-mg and 750-mg doses was associated with significant reduction and abolition, respectively, of pulmonary arterial hypertension. The results are consistent with the interpretation that the pulmonary vasoconstrictive response to endotoxin is mediated through the release of serotonin and that α-m dopa blocks this response by interfering with the synthesis of this intermediary.
Inhibition of distal tubular sodium reabsorption by angiotensin II
Authors: Vander Arthur J.
Published: December 2017

Angiotensin II or norepinephrine was infused directly into the left renal artery of anesthetized dogs undergoing mannitol diuresis, and the right and left kidneys were compared for GFR (Ccr or Cin), RPF (Cpah), sodium excretion, and distal stop-flow sodium and inulin patterns. Both angiotensin and norepinephrine caused similar reductions of GFR and RPF on the left, as compared with the right, but only angiotensin prevented normal lowering of left distal stop-flow sodium concentration, even when length of occlusion was 14 min. The minimum effective dose was 6–12 mµg/kg min, and maximal differences between left and right sodium minima occurred with 50 mµg/kg min. Distal inulin patterns were not altered by angiotensin, nor were "postocclusive" inulin patterns. Clearance data demonstrated that when GFR changes were taken into account angiotensin caused a relative increase in sodium excretion compared to control or norepinephrine-infused dogs. These stop-flow and clearance data support the hypothesis that angiotensin inhibits distal sodium reabsorption by a direct tubular effect. No attempt was made to evaluate possible effects of angiotensin on proximal tubular sodium reabsorption.
Alloxan-diabetic rats during acclimation to cold
Authors: Poe Robert H. , White Joseph W. , Davis Thomas R. A.
Published: December 2017

The survival rate of alloxan-diabetic rats at 5 C was found to be related to the pre-exposure nonfasting blood sugar level. The majority of deaths occurred within the first 2 weeks of cold. Once cold acclimation had been accomplished, the survival rate was 100%. A significant decrease in skeletal muscle glycogen, and the highest percentage of weight loss were found after 2 weeks of cold exposure. A quantitative relationship between survival in the cold and available insulin is suggested. An augmented ability to utilize carbohydrate, related in part to an increased insulin sensitivity, is hypothesized to account for the postacclimation findings.
Effect of thyroparathyroidectomy on uterine sensitivity to estrogen in ovariectomized rats
Authors: Liu Frank T. Y.
Published: December 2017

Evidence has been presented previously indicating that uterine sensitivity of ovariectomized rats to estrogen increased with age up to about 46 days when the animals, if intact, would have reached puberty. With further increase in age, uterine sensitivity to estrogen decreased markedly. The present experiments demonstrate that thyroparathyroidectomy of ovariectomized immature rats did not affect maximal uterine sensitivity to estrogen at about the age of expected puberty. However, thyroparathyroidectomy of ovariectomized rats prevented the marked decrease in uterine sensitivity to estrogen with further increase in age (66–156 days), possibly by decreasing metabolism of administered estrogen after complete depletion of the thyroid hormone.
Role of calcium in initiation of contraction in smooth muscle
Authors: Isojima Chotaro , Bozler Emil
Published: December 2017

Extracellular Ca is not essential for the responses of depolarized aortic muscle of the turtle and the stomach muscle of the frog to acetylcholine. The drug caused contractions after the muscles were washed in KCl or K2SO4 solutions for many hours. Muscles became unresponsive in Ca-free Ringer's solution but they gave responses again after being transferred into Ca-free K solutions. These responses were temporarily increased by a brief treatment with solutions of Na salts. A net uptake of Ca by the fibers under most conditions did not induce contraction. Ca induced a contraction in muscles immersed only in K, but not in Na solutions, although Ca has been found to penetrate equally well in both types of solutions. Therefore, the responses of depolarized muscle to acetylcholine and Ca appear to depend on an increase in sensitivity of the myoplasm produced by K solutions. It is concluded that unresponsiveness in Ca-free Na solutions is mainly due to an interference with electrogenic processes. The presence of Ca in low concentrations diminished responses to acetylcholine and, vice versa, acetylcholine depressed Ca contractions.
Metabolism of palmitic acid in perfused rat heart
Authors: Evans John R. , Opie Lionel H. , Shipp Joseph C.
Published: December 2017

Metabolism of fatty acid was studied in the isolated rat heart perfused with albumin-bound palmitate-C14. Uptake of fatty acid by the heart was related to the concentration of fatty acid present and the molar ratio of fatty acid to albumin in the perfusion fluid. Disappearance of lipid-bound radioactivity from the perfusion fluid (palmitate-C14 uptake) was consistently greater than disappearance of titratable fatty acid. This was attributed to failure of equilibration of unlabeled "endogenous" fatty acid on albumin with added palmitate-C14 and possibly to release of unlabeled fatty acid from the heart to the perfusion fluid. The principal fates of palmitate-C14 were C14O2 and saponifiable tissue lipid. The maximal rate of recovery of palmitate-C14 as C14O2 was equivalent to 83% of total CO2 production of the isolated perfused heart in 30 min.
Rates of biosynthesis of plasma and liver proteins
Authors: Richmond Jonas E. , Shoemaker William C. , Elwyn David H.
Published: December 2017

The rates of synthesis of plasma and liver proteins have been measured in the perfused dog liver and intact rat liver by following the rate of incorporation, over short time intervals, of carbon 14-labeled amino acids of known specific activity. The amino acid compositions of the subcellular fractions of dog liver have been determined. The perfused dog liver synthesized plasma albumin at the rate of 12 mg/min per kg liver, and plasma glycoprotein at the rate of 8 mg/min per kg liver. The rate of albumin synthesis is in reasonable agreement with studies using prelabeled albumin. Liver proteins of both rat and dog appear to contain one or more rapidly turning over fractions. Total rates of synthesis of liver proteins were found to be approximately 200 mg/min per kg liver in both species.
Magnesium exchange between blood and cerebrospinal fluid
Authors: Oppelt W. W. , MacIntyre I. , Rall D. P.
Published: December 2017

Magnesium exchange between plasma and cerebrospinal fluid (CSF) was studied in dogs using Mg28Cl2 and MgCl2. Normal CSF/plasma magnesium ratio in this animal is 1.34. In face of a plasma magnesium concentration 300–400% of normal, the CSF magnesium only rose to a maximum of 21% above control at the end of 5.5 hr. Intravenously injected Mg28Cl2 enters the CSF rapidly, reaching equilibrium within 2–3 hr. The exit rate of magnesium from the CSF has a half time of about 70 min when CSF magnesium levels are close to normal or they are greatly elevated. This rate is not affected by increasing plasma magnesium concentrations. It is concluded that an active transport mechanism is involved in transporting magnesium from blood to CSF, and that diffusion and bulk filtration are responsible for the removal from the CSF.
Effects of prolonged infusion of angiotensin II in normal dogs
Authors: Urquhart John , Davis James O. , Higgins James T.
Published: December 2017

Intravenous infusion of angiotensin II into normal dogs at rates of 20 or 80 µg/kg day for 4–11 days produced elevated urinary excretion of aldosterone without tachyphylaxis. In five of the six animals studied, angiotensin infusion had little or no effect on arterial pressure; in the sixth dog, which received angiotensin at the higher rate, arterial pressure was elevated by 30 mm Hg. Most of the effects of angiotensin II on water and electrolyte metabolism were similar to those of mineralocorticoids: initial transient sodium retention, polyuria, increased fecal potassium excretion, initially negative potassium balance, and diminished plasma potassium concentration. These effects were not observed when angiotensin II was infused into each of three adrenalectomized dogs, which received daily maintenance doses of desoxycorticosterone acetate and cortisone acetate. In addition, however, angiotensin II had a natriuretic action in intact animals, which was more pronounced at the higher rate of infusion. The data suggest that an increase in filtered sodium load was the basis of the natriuresis.
Diverting renal and adrenal vein blood into liver and renal hypertension in dogs
Authors: Kubicek W. G. , Thal A. P.
Published: December 2017

The objectives of this investigation were: 1) To study the effect of diverting renal vein blood flow into the portal vein system upon renal function and hypertension produced by Goldblatt clamps. 2) To study the effects of passing the adrenal vein blood directly into the liver via the portal vein upon arterial blood pressure and upon Goldblatt hypertension. Renal vein blood was diverted into the portal vein by either a reverse Eck fistula or a direct renal to portal vein anastomosis. Clearance rates of p-aminohippurate and creatinine were used to measure renal blood flow and glomerular filtration rate. Goldblatt clamps on the renal arteries of four control dogs resulted in an average blood pressure elevation of 45/28 mm Hg. After a reverse Eck fistula in four dogs, average renal blood flow values indicated a fall of approximately 27% with no change in arterial blood pressure. Subsequent application of Goldblatt clamps resulted in an elevation in arterial blood pressure similar to the control animals. In two dogs, a direct renal to portal vein anastomosis yielded similar results. Diverting adrenal vein blood directly into the liver produced a small rise in the control arterial blood pressure and an apparent increase in the Goldblatt hypertension in two dogs.
Factors affecting acetoacetate production rates by normal and ketotic pregnant sheep
Authors: Bergman E. N. , Kon K.
Published: December 2017

The effects of the administration of insulin, growth hormone, glucose, propionic acid, and butyric acid on endogenous acetoacetic acid (AcAc) production rates and plasma AcAc concentrations were studied in 15 experiments on 12 unanesthetized normal or ketotic pregnant ewes. AcAc production was measured by the isotope-dilution method involving a constant intravenous infusion of AcAc-3-C14. Insulin, glucose, and propionic acid injection markedly reduced AcAc production rates and plasma AcAc concentrations within 1/2 hr. Butyric acid produced opposite effects; about one-fifth was converted to ketone bodies. Growth hormone produced no consistent effects. In all experiments, the plasma AcAc concentration increased or decreased with concomitant changes in AcAc production. It is concluded that, up to a plasma AcAc concentration of about 10 mg/100 ml, ketone-body concentrations in the bloodstream merely are a reflection of the rate of ketone-body production and that utilization, in turn, is dependent upon blood ketone concentrations. It was shown previously that a steady maximal rate of AcAc utilization occurs at plasma AcAc concentrations greater than about 10 mg/100 ml.
Investigation of behavioral performance during urine reinfusion in the male primate
Authors: Teschan P. E. , Murphy G. P. , Sharp J. C.
Published: December 2017

A method employing continuous urine infusion is presented for an experimental study of uremia in primates conditioned to a behavioral schedule requiring modes of performance analogous to those which appear to be deficient in uremic man. The preparation is completely reversible on cessation of infusion, permitting repeated studies in individual animals. Behavioral performance deficits correlated with elevated plasma-urea nitrogen concentrations at or above 95 mg/100 ml, but not with plasma potassium concentrations between 2.0 and 8.5 mEq/liter, sodium concentrations between 135 and 170 mEq/liter, nor with the mechanics of infusion itself.
Hypothalamic temperature in unanesthetized albino rats during feeding and sleeping
Authors: Abrams Robert , Hammel H. T.
Published: December 2017

Stainless steel and polyethylene reentrant tubes were implanted permanently in the brain and abdominal cavity of male albino rats. Thermocouples were placed in the tubes and the leads were counterweighted over the rat cage. Temperatures were recorded continuously for up to 4 hr in unanesthetized, unrestrained rats. A decrease in temperature of the preoptic area usually accompanied sleep. Feeding was consistently associated with a rapid increase in the temperature of the preoptic area, piriform cortex, and abdominal cavity. A significant increase in metabolic rate occurred simultaneously with the rise in temperature of the preoptic region. The caloric content of the diet was not important in determining the degree of temperature rise. The activity associated with eating was postulated to account for the increase in brain and other body temperatures.
Electrophysiological study of renal papilla of golden hamsters
Authors: Windhager Erich E.
Published: December 2017

Electrical potential differences across the tubular epithelium of loops of Henle and of collecting ducts were measured by microelectrode techniques. In a separate series of experiments concentrations of Na22 and of chloride were estimated in fluid collected from Henle's loop and in vas rectum plasma at corresponding cross-sectional levels of the papilla. The lumen of thin ascending limbs of Henle's loop was found electrically more negative (mean: –11 mv), with respect to interstitial fluid, than the lumen of thin descending limbs (–3 mv). No chemical driving force for reabsorptive net diffusion of sodium chloride was found across the wall of thin limbs of Henle's loop. The magnitude of the electrical potential differences observed across the collecting duct epithelium (mean: –14 mv) indicates the existence of active transport of both sodium and chloride across this part of the terminal nephron.
Changes in contractility of frog muscle due to fatigue and inhibitors
Authors: Brust Manfred
Published: December 2017

Continuous activity in excised and curarized frog sartorius muscles reduced twitch tension, contraction rate, and half-relaxation rate, and increased contraction and half-relaxation times. These changes are essentially the same as those reported by others for single fibers. 0.05 mm 2,4-dinitrophenol (DNP), 1 mm NaN3, and 1 mm KCN reduced twitch and tetanus tension in rested muscles. DNP and KCN shortened contraction and half-relaxation times, but NaN3 induced a late prolongation. DNP and NaN3 reduced contraction and half-relaxation rates, but KCN enhanced them. DNP and NaN3 accentuated fatigue declines in tension output. KCN consistently induced twitch treppe, while tetanus tension declined as in unpoisoned fatigue. All the agents enhanced fatigue prolongations of contraction and half-relaxation times. DNP and NaN3 accelerated the fatigue declines of contraction and half-relaxation rates, but KCN retarded them. All inhibitor effects were at least partially reversible. These results differ in many respects from equivalent results obtained with mouse muscles. Known inhibitor mechanisms do not as yet account adequately for the present findings.
Fatty acid synthesis from glucose-1-H3 and glucose-1-C14 in obese-hyperglycemic mice
Authors: Shigeta Yukio , Shreeve Walton W.
Published: December 2017

One or two hours after intraperitoneal injection of trace amounts of glucose-1-H3 and glucose-1-C14 obese-hyperglycemic mice of the Bar Harbor strain converted five to ten times as much of both radioisotopes to total fatty acids of the liver and two to four times as much to total fatty acids of the remaining carcass as their lean siblings. The obese mice generally oxidized glucose-1-C14 to C14O2 and glucose-1-H3 to H3OH at rates equal to those of the lean mice. At 2 hr, 40–45% of the glucose-C14 had been converted to C14O2 and 75–80% of the glucose-1-H3 to H3OH. The maximum conversion of tritium to liver fatty acids was about .4% of the dose at 1 hr and of C14 about .25% of the dose at 1 hr, while for the carcass fatty acids the highest conversion were at 2 hr with about 2.0% of the dose of glucose-1-H3 and 1.8% of the dose of glucose-1-C14.
Renal concentration in the normal dog: effect of an acute reduction in salt excretion
Authors: Goodman Berney , Cohen Jay A. , Levitt Marvin F. , Kahn Melvin
Published: December 2017

In normal anesthetized hydropenic dogs, the TcH2O-Cosm relation generated by infusing hypertonic solutions was variable. In ten dogs TcH2O rose as Cosm increased, attaining a maximum of 3.7–6.3 ml/min ("high curve"). In seven dogs a maximum TcH2O of only 1.4–2.5 ml/min was observed at low Cosm and CH2O was often generated at moderate Cosm ("low curve"). The acute reproducibility of this TcH2O-Cosm relation was examined by allowing Cosm to return to low levels and again infusing the same hypertonic solution. The TCH2O-Cosm relation was duplicated only in dogs initially exhibiting a high curve. Therefore, the effects on TcH2O of acutely reduced sodium excretion were examined only in dogs with an initial high curve relation. After the first diuresis, a phlebotomy or prolonged infusion of 10% mannitol was utilized to induce salt retention. If sodium excretion was reduced to less than 40 µEq/min at low Cosm, TcH2O was decreased during the subsequent diuresis. This impairment in TcH2O generation is attributed to decreased availability of salt for transport into the medulla.
Effect of plasma sodium elevation on renal sodium reabsorption
Authors: Kamm Donald E. , Levinsky Norman G.
Published: December 2017

The effect of elevation of the plasma sodium concentration (PNa) on the tubular reabsorption of sodium (TNa) was studied in 38 dogs infused with hypertonic saline or Ringer's solution. An aortic clamp was used to regulate the glomerular filtration rate (GFR), so that several comparable levels of GFR could be obtained in one dog before and after hypertonic loading. It was found that TNa increases progressively as PNa is elevated, independently of changes in GFR. These results are not due to changes in the plasma bicarbonate-to-chloride ratio; nor to "saturation" of previously "unsaturated" distal tubules; nor influenced by altered aldosterone or antidiuretic hormone activity. Although the mechanism of the increase in TNa is not definitely established by the present experiments, a possible explanation is that it is simply the result of the increased filtered sodium which occurs when PNa is elevated.
Hemodynamics of kangaroos and wallabies
Authors: Maxwell G. M. , Elliott R. B. , Kneebone G. M.
Published: December 2017

Kangaroos and wallabies were anesthetized and cardiac output (Fick) and intravascular pressures were measured. These animals were found to be similar to other mammals with respect to serum electrolytes, hemoglobin, and blood volume. Intravascular pressures are largely comparable with other mammals; there is, however, a significantly higher systemic pressure and vascular resistance in the wallaby than in the kangaroo. There is also a difference in heart rate between the two species. Cardiac output, when corrected for surface area, is similar in the two marsupials and, on a weight basis, resembles that of the dog.
Effects of hypoxia and hyperthermia on hepatic tissue of the dog
Authors: Reed William A. , Manning Robert T. , Hopkins Lenly T.
Published: December 2017

This work was done to evaluate the effects of hepatic hypoxia and hyperthermia in the dog. Hepatic temperature changes were produced by portal vein perfusion and hypoxia by hepatic arterial inflow occlusion. The extracorporeal circuit consisted of a heat exchanger, plastic tubing, pump, and heating jacket. Blood passed from the femoral artery or jugular vein through the extracorporeal circuit and returned to the portal vein. Forty-two animals were studied. Simple arterial inflow occlusion for 1 hr caused death in three of five animals. Perfusion of the liver with venous blood during hepatic artery occlusion was followed by death in all animals while survival was obtained when arterial blood perfusate was utilized. Death occurred if hepatic temperature exceeded 43 C, with one exception. Portal vein infusion without hepatic anoxia resulted in survival of animals following short periods of hepatic hyperthermia up to 46 C. The greatest increase in serum transaminase and alkaline phosphatase followed hepatic hyperthermia or anoxia, or both. Enzyme values gradually returned to normal within 21 days. It is concluded that hepatic anoxia augments the toxic effect of hepatic hyperthermia. The cause of death was not definitely identified.
Stop-flow analysis of the influence of pCO2 on renal tubular transport of K and H
Authors: Ramsay A. G.
Published: December 2017

The stop-flow procedure was used to study the transport of H and K ions in the renal tubule during conditions of high and low pCO2. The increased rate of K excretion during respiratory alkalosis was due primarily to marked increase of K secretion at a distal site. The interrupted stop flow showed that K reabsorption was decreased at a site just proximal to the secretory area. This made a smaller contribution to the increased K excretion. The reciprocal relationship between tubular transport of K and H was demonstrable. CO2 tension appeared to influence HCO3 reabsorption and H secretion in both the distal and proximal tubule, whereas its effect on K transport was confined to the distal tubule. Hypercapnia never completely obliterated the distal secretory site. It is suggested that a pCO2-dependent H carrier is not shared with K. The increased K secretion of hypocapnia is more likely the result of increased K within the distal tubular cells.
Click-evoked potential map from the superior olivary nucleus
Authors: Biedenbach M. A. , Freeman W. J.
Published: December 2017

Potential distributions in the superior olivary nucleus were mapped in response to ipsilateral and contralateral click stimulation. From the medial segment of the superior olivary nucleus a dipole field was recorded which reversed polarity and slightly shifted the zero isopotential on contralateral stimulation. On the basis of the anatomic arrangement the potentials of the lateral segment of the superior olivary nucleus are discussed in terms of a closed field.
Incorporation of l-lysine-U-C14 into proteins of cryptorchid testis slices
Authors: Davis Joseph R. , Morris Robert N. , Hollinger Mannfred A.
Published: December 2017

The incorporation of l-lysine-U-C14 into protein of slices of experimentally induced cryptorchid testes of the rat has been studied at various time periods ranging from 4 to 40 days after abdominal transplantation. Comparisons of protein labeling from radioactive lysine into slices of adult scrotal testes, immature testes, and an interstitial-cell testicular tumor of the mouse have also been carried out. In addition, the effects of temperature and of exogenous glucose on protein labeling of these tissues have been investigated. The data obtained indicate that the incorporation of labeled lysine into protein of slices of cryptorchid testes is markedly greater than that observed for slices of scrotal testes obtained from the same animal. It is suggested that of the various cell types found in the rat testis, the spermatogonia and primary spermatocytes demonstrate the highest degree of protein labeling from radioactive lysine and that the enzymatic systems involved in the incorporation of radioactive lysine into protein of the spermatids display the most susceptibility to elevated temperatures and the greatest sensitivity to the addition of exogenous glucose.
Interaction between CO2 and citrate ions in medullary reticular formation
Authors: DeHaven K. E. , Carpenter F. G.
Published: December 2017

Ventilation was recorded in anesthetized rats during the injection of small quantities of Na citrate solution near the obex and during the application of electric pulses to the same region. Increases in Ve or ventilatory arrest were typical responses to these stimuli. Observations were made to determine whether either response could be altered by the inhalation of 10% CO2 or 7% O2 gas mixtures. Responses to 1.8 µl 2.8 mm Na citrate injections were diminished from controls while the animals were hyperventilating during CO2 administration. In contrast, ventilatory responses to 1.4 mm Na citrate injections were potentiated during hyperventilation resulting from 7% O2. Thus, hypercapnia depressed and hypoxia enhanced the excitability of those neurons of the medullary reticular formation which respond to citrate. The stabilizing action of calcium on the neurons is almost certainly removed by citrate. Several other carbohydrate intermediates besides citrate bind calcium ions as well. It is proposed that CO2 under certain conditions might thereby regulate the repetitive discharge of certain groups of neurons in the medullary reticular formation.
Effect of lysine vasopressin dimers on blood pressure and some endocrine functions
Authors: Schally Andrew V. , Bowers Cyril Y. , Kuroshima Akihiro , Ishida Yuichi , Carter Weldon H. , Redding Tommie W.
Published: December 2017

Some biological properties of lysine vasopressin dimers, derived by polymerization from natural lysine vasopressin or made synthetically, were studied and compared to those of natural lysine and arginine vasopressin or USP posterior pituitary standard. "Natural" and synthetic dimers caused patterns of blood pressure responses different from those obtained with vasopressin. In the urethane-Dibenzyline-treated rat, the rise in blood pressure obtained with dimers developed more slowly and lasted much longer than that given by vasopressin or angiotensin II. The dimers also caused long-lasting blood pressure responses in the anesthetized dog. In the anesthetized chicken the dimers caused a prolonged fall in blood pressure clearly different from the effect of vasopressin. The antidiuretic responses to the dimers in the rat was of slightly shorter duration than that to USP posterior pituitary standard. The dimers also had significant corticotrophin-releasing factor (CRF) activity at the level of 30 mU pressor activity, as evidenced by the release of ACTH in the rat treated with morphine and Nembutal. Both "natural" and synthetic dimer caused depletion of ovarian ascorbic acid in the rat pretreated with gonadotrophin. "Natural" but not synthetic dimer increased the release of I131 from the mouse thyroid.
Effects of surfactants on the twitch tension of frog sartorius muscle
Authors: Webb George D.
Published: December 2017

Many types of cells show permeability increases to ions and to various uncharged molecules when exposed to surface-active agents (surfactants). Nonionic surfactants are less effective than ionic surfactants in increasing permeability and in depolarizing nerve and muscle cells. In the present experiments the strength of isometric twitch responses of directly stimulated frog sartorius muscles was measured. Ionic surfactants generally produced an irreversible decrease in the twitch response, whereas nonionic surfactants (at equimolar concentrations) had little effect. Aerosol OT conditioned muscles so that curare or neostigmine appeared to produce a decrease in the twitch tension of directly stimulated fibers. Possibly the Aerosol OT treatment increased the permeability of the conducting membrane, allowing curare and neostigmine to interact with the acetylcholine system proposed by Nachmansohn. The above observations could be accounted for by increases in permeability caused by the ionic surfactants. Two observations suggested additional actions of ionic surfactants: low concentrations of cetyltrimethylammonium produced a reversible decrease in twitch tension; low concentrations of anionic surfactants caused an increase in contractile tension.
Thioglycollate-stable luteinizing hormone and corticotrophin-releasing factors
Authors: Ramirez V. D. , McCann S. M.
Published: December 2017

Crude acidic extracts of beef stalk-median eminence tissue depleted ovarian ascorbic acid on injection into immature rats pretreated with gonadotrophins. They also elevated plasma luteinizing hormone (LH) activity in ovariectomized rats which had been pretreated with both estrogen and progesterone. This activity could not be explained by possible LH contamination of the extracts. Since cerebral cortical extracts prepared similarly possessed little or no activity, it is concluded that beef stalk-median eminence tissue contains a specific LH-releasing factor (LH-RF). These same extracts possessed an ACTH-releasing action, as judged by adrenal ascorbic acid depletion induced in rats with median eminence lesions, which could not be accounted for by the minimal contamination of the extract with ACTH itself. Thioglycollate failed to alter either the LH or ACTH-releasing activities of these extracts under conditions which markedly reduce the activity of Pitressin. It is concluded that the LH-RF and corticotrophin-releasing factor resident in beef hypothalamic tissue are dissimilar from the known neurohypophysial polypeptides.