bluuebunny/crossref_metadata_2025 huggingface dataset:
Excretion of d-malic acid in the chicken
Authors: Vishwakarma P. , Lotspeich W. D.
Published: December 2017

The excretion of the physiologically inert d-malic acid has been studied in the chicken. It is actively secreted by the renal tubule. There is no mutual interference between the capacity to secrete d-malic and PAH. Benemid does not inhibit d-malic secretion. N'-methylnicotinamide, cyanine no. 863 and Priscoline likewise have no effect on d-malic secretion. During secretion by the tubules d-malic acid retains its optical configuration. It is concluded that the renal tubular secretion of d-malic acid occurs by a mechanism different from the one for other organic acids or organic bases reported thus far.
Radioautography of the conduction system of the dog's heart with I131
Authors: Uhley Herman N. , Reich Stanley B. , Rivkin Laurence
Published: December 2017

The conduction system of most mammalian hearts has been difficult to visualize. This study demonstrates the affinity of superficially applied radioactive iodine for the conduction system of the dog and demonstrates the ventricular condition system by radioautography.
Influence of decreased vascular pressures on mechanics of ventilation in dogs
Authors: Lewin Richard J. , Cross Cecil E. , Rieben P. Andre , Salisbury Peter F.
Published: December 2017

In closed-chest and open-chest dogs the peak insufflation tracheal pressure during constant-volume, positive pressure ventilation increased whenever the systemic arterial pressure was lowered by bleeding. The tracheal pressure was also recorded in open-chest dog experiments, where the pulmonary and the systemic circulations were perfused by separate perfusion systems, the output of which was known. When the blood flow in one circuit was kept constant while the flow in the other was decreased, increases of the tracheal pressure were observed. The effect of systemic hypotension upon tracheal pressure disappeared after cooling or sectioning of the vagi. On the other hand, the effect of decreased pulmonary flow upon tracheal pressure persisted after denervation of the lungs and was observable even in dead dogs. We conclude that a) decrease of the systemic arterial pressure (bleeding) causes reflex increase of the peak insufflation tracheal pressure which is mediated by the vagus nerve. b) decrease of the pulmonary blood pressures and of the pulmonary blood volume below normal cause increased peak insufflation pressures, which are believed to represent decreased pulmonary compliance.
Serum factor in fasted rats inhibiting carbohydrate metabolism in the isolated diaphragm
Authors: Berman E. R. , Wertheimer E.
Published: December 2017

A factor has been found in the serum of fasted rats which inhibits glucose uptake and glycogen synthesis in the isolated rat diaphragm. It does not affect CO2 production or O2 uptake. It is nondialyzable, stable in the cold and also stable when heated to 58°C for 1 hour. It was found in Cohn fraction IV-V. Its action did not resemble any of the known hormones, nor could it be identified as one of the inhibitory factors found in diabetic serum.
Glucose and pyruvate metabolism in liver slices of chronically uremic rats
Authors: Cummings Nancy Boucot , Zottu Sylvia M.
Published: December 2017

The pathways of glucose and pyruvate metabolism in the liver of the chronically uremic rat were measured in vitro. Chronic uremia was produced in rats by an operative method preceding the experiments by 2–8 months. One gram of liver slices per flask was incubated for 90 minutes at 37°C in a high-potassium medium containing either uniformly labeled glucose-C14 or pyruvate-2-C14 as a substrate. Determinations of blood urea nitrogen and blood glucose, liver glycogen, lactic acid, and of C14 incorporation into carbon dioxide, fatty acids, medium glucose and glycogen were compared in liver slices from uremic and littermate control rats. No statistically significant difference in glucose or pyruvate metabolism as evaluated by these methods was found between the control and the uremic rats' liver slices. Contrary to data reported by other workers, no defect in hepatic glycogen metabolism was found. This discrepancy is attributed by the authors to the fact that other workers have studied their uremic animals within 12–36 hours after the anesthesia and surgery required to induce experimental uremia.
Muscle-stimulating fatty acid isolated from placenta
Authors: Ichikawa Shigetaka
Published: December 2017

A smooth-muscle-stimulating fatty acid has been isolated from the human placenta. The neutralization value, iodine value and results obtained from alkali-isomerization, biological assay and paper chromatography provided evidence indicating that the active substance is eicosatetraenoic acid (arachidonic acid). The active fraction manifested the following biological properties: a) delayed-slow-contracting action on the isolated intestine and uterus, which seemed to be a direct one on muscle fibers; b) hypotensive action on rabbit blood pressure in a dose of 5 µEq. The evidence considered in relation to the literature on smooth-muscle-activating, lipid-soluble acids, strongly indicates that eicosatetraenoic acid is more active than the previously studied fatty acids, and among the most active lipid-soluble smooth-muscle-activating substances.
Initiation of lactation in rats by nonspecific stresses
Authors: Nicoll Charles S. , Talwalker P. K. , Meites Joseph
Published: December 2017

Sixty mature, virgin female rats were divided into six groups of 10 each and injected subcutaneously for 10 days with 10 µg estradiol in 0.1 cc corn oil. For the following 5 days the groups were treated as follows: 1) controls, 0.1 cc saline injected subcutaneously once daily; 2) severe cold (0°C) 24 hr/day; 3) intense light and heat for 12 hr/day; 4) restraint, 12 hr/day; 5) starvation, no food or water for 5 days; 6) subcutaneous injection of 0.1 cc or 0.2 cc of 10% formaldehyde once daily. The mammary glands of the control rats regressed from a lobulo-alveolar system to a bare duct system during the period of saline injections. The stressed groups all showed variable degrees of lactation after treatment. It is concluded that nonspecific stresses can promote the secretion of prolactin and ACTH from the anterior pituitary in amounts adequate to induce lactation in estrogen-primed rats. The possible role of stresses in initiating lactation at parturition and under other circumstances is considered, and a common mechanism controlling the secretion of ACTH and prolactin is postulated.
Corticosteroids and incorporation of C14-phenylalanine into protein of isolated rat diaphragm
Authors: Wool Ira G. , Weinshelbaum Edward I.
Published: December 2017

Prior treatment of rats with cortisone (2 mg/day) decreased l-phenylalanine-U-C14 incorporation into protein of isolated diaphragm. This action was not affected by a 100-fold change in the phenylalanine concentration, indicating that the steroid depresses protein biosynthesis in muscle. Hydrocortisone (50 µg/ml) added in vitro did not alter C14-phenylalanine incorporation. Large changes in intracellular potassium concentration were without influence on phenylalanine incorporation into protein of diaphragms from normal, adrenalectomized or cortisone-treated rats.
Extraocular proprioception in electrically induced eye movements
Authors: Hyde Jane E. , Davis Lois M.
Published: December 2017

Ocular movements evoked by stimulation of brain-stem sites in the feline encéphale isolé have been analyzed in an attempt to demonstrate an extraocular proprioceptive mechanism. Procedures designed to reduce extraocular proprioceptive input to the central nervous system included tenotomy of the muscles of one eye, procaine block of one or both Gasserian ganglia, and acute cerebellectomy. None of these procedures resulted in a consistent alteration in accuracy of the induced oculomotor responses. Immobilization of one eye, however, significantly reduced the accuracy of the freely moving eye in assuming the same final position with repeated stimulation of one site. All procedures tested, including occipital lobectomy, resulted in a significant shift of the final position reached by the eyes in response to repeated stimulation of one site. While the shift, unlike the decrease in accuracy seen with immobilization, cannot be interpreted as evidence for an extraocular proprioceptive mechanism, it is discussed with reference to the significance of the ‘goal’ position obtained by repeated stimulation of one site at constant stimulus parameters.
Norepinephrine sensitivity of isolated rabbit aorta strips in solutions of varying pH and electrolyte content
Authors: Williamson A. W.R. , Moore Francis D.
Published: December 2017

Using a preparation of isolated vessel wall, observations have been made upon the sensitivity of the smooth muscle to 10 µg/l. of norepinephrine in various extracellular media. Varying the pH from 7.14 to pH 7.56 did not alter the sensitivity. More gross alterations in pH in either direction (pH 6.80 or 7.70) diminished the response equally. Lowering the sodium concentration and raising the potassium concentration both singly or together increased the sensitivity of the arterial strip. A rise in sodium concentration and a fall in potassium concentration either individually or in combination caused a lessened response to norepinephrine. Increasing the norepinephrine concentration to 100 µg/l. caused a greater contraction of the vascular smooth muscle, the degree of this response then being unaltered by pH and electrolyte changes in its environment within the range investigated. This strip of vessel wall from the largest vascular compartment outside of the heart appears to show a remarkable stability and regularity of reaction, despite wide variation in its extracellular environment, well beyond the limits of acid-base and electrolyte alteration commonly encountered in clinical medicine and surgery.
Renal excretion of thiamin by the dog
Authors: Malnic Gerhard , da Silva Alberto Carvalho , de Angelis Rebecca C. , Gomes Zulmira J.
Published: December 2017

Simultaneous thiamin and creatinine clearance determinations in unanesthetized dogs revealed a pattern of excretion characteristic of a substance actively excreted by the renal tubules. The maximum tubular excretory capacity per minute (Tm) calculated at high thiamin plasma levels was negative, unless a correction factor (FW) of 0.63, calculated from the clearance values, was applied. Under these conditions, the mean Tm value was 1463 µg/min. By means of perfusion experiments on isolated dog kidneys it was shown that there was very little or no protein binding of thiamin. In extraction-ratio determinations on unanesthetized dogs it was shown that thiamin was not destroyed by the kidney and that the extraction of thiamin and PAH were similar. At varying urine flows with high thiamin plasma levels, a correlation between water reabsorption and thiamin excretion could be observed, suggesting the occurrence of back-diffusion of thiamin under these conditions.
Effects of adrenalectomy, acute acidosis and adrenal corticoids on renal deamination enzymes
Authors: Boris Alfred , Gordon Edgar S.
Published: December 2017

The effects of adrenalectomy, acute acidosis and treatment with adrenal steroids upon the activities of renal glutaminase, asparaginase, guanase and adenosine deaminase were studied in the rat. None of the procedures or treatments employed affected significantly the in vitro activities of renal glutaminase, asparaginase and guanase. Pretreatment of rats with hydrocortisone or aldosterone resulted in the increased activity of renal adenosine deaminase.
Hypothalamus and respiratory minute volume
Authors: Redgate Edward S.
Published: December 2017

Minute volume of respiration was measured in 21 cats. Hypodermic tubing and electrodes were implanted in the hypothalamus. Minute volume of respiration was measured before and after depression of the hypothalamus by coagulation with high frequency current or by microinjection of 4% thiopental into sites in the hypothalamus. Depression of the hypothalamus was followed by a 20–30% decrease in minute volume. The results were statistically significant. Depression of the thalamus by coagulation or microinjection of thiopental was not followed by a significant change in minute volume. Intravenous injection of the amount of thiopental injected into the hypothalamus did not alter minute volume. Minute volume decrease was often associated with blood pressure and muscle tone decreases, but in several cases, minute volume decreases were independent of blood pressure and muscle tone. The evidence supports the argument that tonic discharges from the hypothalamus increase the excitability of respiratory reflex pathways and effect increased minute volume.
Effect of lethal doses of bacterial endotoxin (E. coli) on sympathetic neurohormones in the rabbit
Authors: Heiffer Melvin H. , Mundy Roy L. , Mehlman Benjamin
Published: December 2017

Lethal doses of E. coli endotoxin, administered intravenously, produced an immediate, precipitous fall in blood pressure, which returned to near normal levels over the next hour. Approximately 1 hour after endotoxin administration the blood pressure began to fall gradually and continued to fall until the death of the animal. During the period of immediate blood pressure fall there was no significant increase in the circulating catecholamines and no decrease in the adrenal content of these hormones. This suggests that the sympathetic nervous system may be depressed during the initial phases of endotoxin poisoning so that the sympathetic discharge which is seen during hypotension, produced by other means, is inoperative. When the pressure returned to near normal levels, the circulating catecholamine concentrations were elevated and the adrenal gland content of these materials was decreased. When the pressure dropped to levels below 60 mm Hg, 4–6 hours after endotoxin administration, the circulating catecholamine level was still statistically elevated and the adrenal content of catecholamines was further depressed. These experiments demonstrate that the blood pressure levels, during endotoxin administration, do not parallel expected peripheral catecholamine concentrations. During the late stages of endotoxin poisoning there is evidence that the animal becomes refractive to increased endogenous epinephrine and norepinephrine.
Absorption of iso-, hypo- and hypertonic solutions from small intestine of cats
Authors: Ullmann T. D. , Dikstein S. , Bergmann F. , Birnbaum D.
Published: December 2017

The movement of water, sodium and chloride through the intestinal membrane of the cat was investigated. Solutions of sodium chloride, sodium bicarbonate and ammonium chloride in iso-, hypo- and hypertonic concentrations were used. The changing concentration of added inulin was used as an indicator of the net movement of water. Net sodium penetration through the intestinal membranes from the outside into the lumen was more rapid than that of chloride, as shown by the rate of appearance and the final concentration of these ions in the loops which were initially free of them. These findings are explained by ascribing to the intestinal membranes the properties of cation exchanging systems. Water was found to move in the absence of, or against an osmotic gradient, indicating the existence of a separate, ‘active’ transport mechanism for water.
X-irradiation lethality aggravated by sexual activity of male mice
Authors: Rugh Roberts , Grupp Erica
Published: December 2017

Sixty CF1 mice were given 600 r whole body x-irradiation, a dose calculated to kill 30% in 30 days. Half were isolated as controls and the remaining half were provided with an adequate number of nonpregnant, mature females for daily matings for the next 30 days. The controls showed 33% lethality while the experimentals, aggravated by frequent sexual activity, showed 73% lethality. Sexual activity more than doubled the lethal effect of 600 r x-rays. Litters derived from x-irradiated, sexually active males mated during the 1st week resulted in an average of 3.1; matings during the 2nd week produced an average of 2.7 (normal control size is 9.6). Matings during weeks 3–7 were sterile. Fertility was recovered by some at 8 weeks (litter size, 6.9) and by some as late as 75 days. Control x-irradiated males, after resumption of fertility, produced litters of 7.3.
Hibernation and cold storage effects on phosphates in hamster blood
Authors: Brock Mary Anne
Published: December 2017

No significant changes from control levels were found in phosphate fractions of erythrocytes and plasma analyzed in cold-exposed golden hamsters ( Mesocricetus auratus). The effect of depressed temperature on red cells after 3 days of hibernation or storage was reflected in decreased easily hydrolyzable phosphate and increased difficultly hydrolyzable phosphate. These changes were interpreted as probably the result of diminished removal of triosephosphate followed by an increase in phosphorylated hexoses. ADP was not rephosphorylated at a rate equal to the esterification of hexoses by ATP, and a diminution of ATP occurred. Furthermore, significant increases in inorganic phosphate occurred in hibernator's erythrocytes and plasma. These were accounted for in the plasma as the result of phosphatase action on phospholipids. In erythrocytes, the other organic phosphate compounds must contribute to this fraction. Six hours following the initiation of arousal from hibernation, an almost complete return to control values for phosphate fractions was observed.
Glucose inhibition of fatty acid oxidation by rat diaphragm
Authors: Schwartzman Leonard I. , Brown Josiah
Published: December 2017

The effects of glucose on the uptake and oxidation of albumin-bound palmitate-1-C14 by the rat diaphragm in vitro were studied. The conversion of labeled palmitate to C14O2 was greater in diaphragms from fasted than fed rats. High concentrations of glucose or lower concentrations of glucose with insulin decreased the production of C14O2 by diaphragms from 24-hour-fasted rats. Glucose with insulin did not affect the uptake of palmitate. The glucose effect on palmitate oxidation in vitro seems dependent upon adequate glucose uptake and utilization.
Stop-flow analysis applied to the excretion of hemoglobin
Authors: Malmendier C. L. , DeKoster J. P. , Veiken F. Vander , Brauman H. , DeMyttenaere M. , Lambert P. P.
Published: December 2017

The stop-flow analysis has been applied to the study of the excretion of hemoglobin, in order to compare the physiological data with the morphological views. The study of the ratio U/P hemoglobin/U/P creatinine suggests that this protein penetrates the tubular lumen by diffusion during the ureteral occlusion and progressed slowly under influence of water reabsorption. During this migration, hemoglobin undergoes the effects of a double reabsorption: one in the middle part of the proximal convoluted tubule, the other more distally situated in a zone not distinguishable from the site of sodium reabsorption.
Distensible behavior of pulmonary artery
Authors: Frasher Wallace G. , Sobin Sidney S.
Published: December 2017

Pressure-volume determinations were made in a reproducible proximal segment of the pulmonary arterial system of swine using a known reciprocating volume at physiologic rates of cycling. The distensible response of vessels separated from normal supporting structures depended on extraneous mechanical influences. Antecedent freezing decreased distensibility and altered the pattern of response. At low inputs fresh specimens in continuity with supporting structures displayed pressure-volume curves of increased distensibility with increasing volume. At high inputs the curves were of sigmoid shape with a lower region of increased instantaneous distensibility and a higher region of decreased instantaneous distensibility. The findings differ from distensibility studies of large arteries by other methods.
Electroencephalogram during arousal from hibernation in the birchmouse
Authors: Andersen Per , Johansen Kjell , Krog John
Published: December 2017

In the birchmouse, Sicista betulina, electrical activity of the brain was recorded at an oral temperature as low as 2.5°C. At body temperatures below about 10°C the activity consisted of bursts of slow waves separated by silent intervals. On increasing body temperature during the arousal this pattern was gradually replaced by activity of higher frequency until a normal electroencephalogram was recorded at about 30°C. No typical desynchronization of the EEG in response to sensory stimulation was noted until the body temperature reached that same level. The vocalization at low body temperatures induced by faint stimulation therefore seems to be unrelated to EEG desynchronization. The increase of recorded muscle-action potentials during the arousal from hibernation paralleled the increase in oxygen consumption and body temperature described previously (1).
Effects of epinephrine and Ca on contractile strength and Ca45 exchange in rabbit atria
Authors: Briggs Arthur H. , Holland William C.
Published: December 2017

A comparison of the effects of Ca and epinephrine on contractile tension changes and Ca45 exchange in isolated rabbit atria was made. Dose response curves of Ca were determined with and without epinephrine (2.7 x 10–5 m) and dose response curves of epinephrine were determined with three concentrations of Ca in the media (0.3 mm, 2.4 mm and 9.6 mm) at both pH 6.9 and pH 7.75. Epinephrine enhanced the effect of a given concentration of Ca two to three times in a competitive manner. However, Ca acted as a noncompetitive inhibitor on the response of atria to epinephrine. Ca45 studies revealed that epinephrine decreased Ca influx. This effect was enhanced by increasing the extracellular Ca concentration. Ca45 efflux was not affected by epinephrine. Increasing the pH acted similar to epinephrine. These data suggest that epinephrine increases contractile strength of the heart by at least two mechanisms, one involving an increased binding of calcium in the membrane (competitive), the other involving a noncompetitive antagonism, perhaps of another essential component in the reaction, such as Mg++.
Comparison of direct cerebral and cerebellar cortical responses in the cat
Authors: Rhoton Albert , Goldring Sidney , O'Leary James L.
Published: December 2017

Surface-evoked cerebral and cerebellar responses were compared in 35 cats. Single stimuli and 1-second trains (6 and 20/sec.) were used. Effects of gamma aminobutyric acid (GAB) applied to the cortical surface and of Nembutal and procaine injected intravenously were studied. Response of cerebral cortex to a single shock shows at least four components: initial negative spike, second negative wave, after-positivity, and slow negativity. Cerebellum shows only the initial negative spike and the slow negativity, second negative and after-positivity components being absent. In both cerebrum and cerebellum slow negativity shows summation with serial stimulation. Application of GAB to the cerebellar surface causes replacement of the negative spike by a positive one and a concurrent reduction in amplitude of slow negativity. In cerebral cortex Nembutal produces a striking augmentation of singly or serially evoked slow negativity, but marked amplitude reduction or reversal to positive polarity of the serially evoked primary spikes. By contrast procaine abolishes summed slow negativity of cerebral cortex leaving serial spikes unaffected. In the cerebellum Nembutal and procaine have no effect upon the direct cortical response at dosage sufficient to produce cerebral alterations. Thus synaptic activity signaled by the responses studied appears to be more susceptible to Nembutal and procaine in cerebrum than in cerebellum.
Insulin and incorporation of radioactivity into nucleic acid fraction of isolated diaphragm
Authors: Wool Ira G.
Published: December 2017

Insulin in vitro stimulated the incorporation into the nucleic acid fraction of isolated rat diaphragm of radioactivity from d-glucose-U-C14, adenine-8-C14 and orotic acid-6-C14; insulin had no effect on the incorporation of thymine-2-C14 into muscle nucleic acids. Insulin enhanced the incorporation into nucleic acids of C14 from adenine and orotic acid in the absence of added glucose, and incorporation of adenine-8-C14 was not influenced by glucose concentration over the range 0–600 mg %.
Control circulatory values of morphinepentobarbitalized dogs
Authors: Deavers S. , Smith E. L. , Huggins R. A.
Published: December 2017

Mean control data on a series of 100 dogs are presented. Cell volume, measured with Cr51-tagged red cells and plasma volume determined simultaneously by T-1824 dye was 33.5 ± 0.74 cc/kg and 50.2 ± 1.11 cc/kg, respectively. The venous hematocrit was 45.2% and the circulatory/venous hematocrit ratio was 0.89 ± 0.01 for the group. The plasma protein concentration of these animals was 6.25 ± 0.07 gm/100 cc. No difference in blood volume per unit of body weight was found between large (12.6 kg) and small (5.8 kg) dogs. The femoral mean systolic pressure was 139.0 ± 2.53 mm Hg, the diastolic pressure 65.6 ± 1.46 mm Hg and the heart rate 85.9 ± 2.86/min.
Hormonal control of plasma and erythrocyte volumes of rat uterus
Authors: Davis James S.
Published: December 2017

The hyperemic response of rat uterus to estrogen was studied in spayed and intact animals by labeling plasma and erythrocytes with radioisotopes. Animals were frozen in liquid nitrogen and uteri dissected in the frozen state to prevent loss of blood. Volumes per 100 mg dry tissue were calculated from radioactivity measurements. Circulation time studies were done on spayed animals to determine the amount of plasma label lost to extravascular space before and after estrogen treatment. Volume determinations were also done on uteri at room temperature for comparison to values obtained from frozen uteri. Plasma volume increased 125% of the control value 3 hours after a single injection of 2 µg estradiol-17-ß after correction for plasma label located in extravascular space. Erythrocyte volume increased only 60% which resulted in a decrease in hematocrit from 37.68% to 28.40%. A similar decrease in hematocrit was found in intact animals just prior to stage 1 of the estrous cycle. Possible explanations for the decrease were considered.
Effects of adrenalectomy, aldosterone and dehydration on electrolyte metabolism of rat renal cortex slices
Authors: Crabbé Jean , Nichols George
Published: December 2017

An attempt has been made to study the action of aldosterone on tubular reabsorption of sodium using in vitro incubation of rat renal cortex slices. In normally hydrated animals neither adrenalectomy nor aldosterone, whether injected into the animal or added to the incubation medium, influenced significantly the rate and extent of slice sodium and water accumulation and potassium depletion. However, effects on other variables were found. After adrenalectomy, the oxygen consumption of the renal cortical tissue was decreased 10–13.5% and the ammonia production 27–33%. Unlike oxygen consumption, ammonia production was influenced by aldosterone; when the hormone was injected into rats the renal cortical ammonia production increased 27–65%. Ammonia concentrations in the incubation media could account for the progressive alkalinization observed with increasing time of incubation. Hydropenia resulted in an increased sodium accumulation and potassium depletion, and a decreased oxygen consumption and ammonia production by incubated slices from intact as well as adrenalectomized rats.
Glucose-induced delay in fat absorption and in appearance of Stypven clot accelerator
Authors: Tilden John H. , Shipley Robert E.
Published: December 2017

When oleic-1-C14 acid was fed to dogs, the plasma isotope, lactescence and Stypven accelerator activity (AA) appeared simultaneously 2–4 hours after ingestion. When either peanut oil or labeled oleic acid was preceded, accompanied and followed by glucose feeding, the appearance of lactescence, AA and plasma isotope was again simultaneous but markedly delayed until 8–10 hours after fat ingestion. Serial roentgenograms of dogs given radiopaque (iodinated) peanut oil plus glucose showed that the delay in absorption of fat was not attributable to delayed gastric emptying. Although the appearance of fat in the small intestine was evident within 1–3 hours after ingestion, plasma lactescence and AA were not seen for 9–12 hours. The delay in intestinal absorption of orally ingested fat caused by glucose was also demonstrated in rats and in human subjects.
Survival of strain 129 dystrophic mice in parabiosis
Authors: Pope R. S. , Murphy E. D.
Published: December 2017

Postweaning-age dystrophic mice were joined in parabiosis with normal and carrier partners of the same sex and strain. The parabionts and single dystrophic controls were fed a soft diet and received Terramycin in the drinking water. There was no significant difference in survival time or attained age among the groups of dystrophics. There was no evidence of amelioration of the dystrophic process by parabiosis in terms of survival time, weight gain, degree of muscular weakness, or histologic analysis at autopsy. The normal partners did not develop muscular weakness, nor was there histologic evidence of induction of the lesions of dystrophy. It is concluded that there is no evidence of a blood-borne substance present in sufficient concentration in the circulation of the normal partner which can influence the course of the disease, and that there is no indication of a blood-borne substance in the circulation of the dystrophic which can cause dystrophy.
Intracellular pH of isolated perfused turtle heart
Authors: Waddell William J. , Hardman Harold F.
Published: December 2017

Hearts from 15 painted turtles ( Chrysemys picta) were perfused for 30 minutes at 23°–26°C with a buffered salt solution. The pH of the perfusing solution was varied between 6.5 and 9.5. The intracellular pH values of the ventricles were calculated from the distribution of the weak acid, 5.5-dimethyl-2,4-oxazolidinedione (DMO). It was found that the extracellular pH (pH e) and the intracellular pH (pH i) under these conditions could be related by the equation: pH i = 0.617 pH e + 2.98.
Effects of hypocapnia and hypercapnia on myocardial contractility
Authors: Monroe R. Grier , French Gordon , Whittenberger James L.
Published: December 2017

Moderate elevations of pCO2 (61–75 mm Hg) did not consistently depress myocardial contractility as determined by standard ventricular function curves. With an altered preparation in which heart rate and left atrial pressure were held constant, a pCO2 of 60–75 mm Hg was accompanied by an average reduction in stroke work to 73.6% of its control value, while hypocapnia with an alveolar pCO2 of 6–13 mm Hg was unaccompanied by any consistent reduction in stroke work.
Effects of serotonin on circulation in the rat kidney
Authors: Dolcini Horacio A. , Zaidman Isidoro , Lichtenberg Franz , Gray Seymour J.
Published: December 2017

The effects of serotonin upon the circulation of the rat kidney were studied by a modified benzidine staining technique and by the intravascular injection of India ink. A marked vasodilation with increased filling of the glomeruli and peritubular capillaries was noted 15 minutes after the injection of 10 mg/kg of serotonin reaching a maximum at 30 minutes. At 90 and 180 minutes there was a striking change in the cortical zone where the glomeruli appeared bloodless, while the circulation of the juxtamedullary areas remained unaltered. These studies indicate that serotonin in the doses used produced a shunting effect at the juxtamedullary area, although no cortical or tubular necrosis was demonstrable by hematoxylin and eosin stain. Reproduction of the same vascular pattern with intra-arterial India ink and the benzidine staining of the red blood cells support the concept that both red blood cells and plasma are shunted away from the cortex at the juxtamedullary area.
Cross circulation at the small blood vessel level in the dog paw
Authors: Davis D. L. , Hamilton W. F.
Published: December 2017

Small vessel responses to maximal sympathetic stimulation have been studied by establishing a cross circulation, at the small blood vessel level, between the two hind legs of the dog. This technique permitted the differentiation between vascular responses occurring upstream and downstream from the level of the cross circulation. Sciatic nerve stimulation stopped flow in both upstream and downstream arterial segments. Lumbar sympathetic trunk stimulation (which did not include all nerves supplying the digital vasculature) stopped flow in the upstream arteries, but allowed a restricted flow to continue in the downstream segments. Both lumber and sciatic nerve stimulation produced intense constriction of dorsal metatarsal and digital veins. Establishment of a cross circulation at either the dorsal metatarsal or dorsal digital vein level proved that in unstimulated vessels a retrograde flow from small vein to small artery was possible. During maximal sympathetic stimulation, constrictive closure of small veins prevented flow from occurring either upstream or downstream in metatarsal and digital veins until perfusion pressures were increased to approximately 100 mm Hg. Thus, constrictive closure of the venules protected the capillaries from the high small vein pressures developed during maximal sympathetic stimulation.
Baroceptor reflex mechanisms in swine
Authors: Booth Nicholas H. , Bredeck Henry E. , Herin Reginald A.
Published: December 2017

In swine with intact vagi and carotid sinuses, occlusion of both common carotid arteries caused a significant rise in blood pressure, whereas desocclusion of these vessels was followed by an immediate and equally significant drop in blood pressure to preocclusion values. Sectioning both vagi did not abolish this pressor reflex. Denervation of either carotid sinus area abolished the pressor reflexes arising from that side while from the intact side the reflex could still be elicited. Bilateral vagotomy and denervation of the carotid sinuses failed to abolish completely the pressor response produced by carotid occlusion, which lends support to the existence of cephalic baroceptors. The results indicate that swine exhibit cardiovascular reflexes initiated by baroceptor stimulation in the carotid sinus area. However, the sensitivity of the receptors seemed to be below that in some other animal species, i.e. the magnitude of the responses was by no means as great in the pig as in the dog. In every instance, the pressor response elicited by carotid occlusion was accompanied by a significant increase in heart rate, which returned to normal following desocclusion of the artery. Heart rate was also significantly increased by bilateral vagotomy.
A common pathway for sugar transport in hamster intestine
Authors: Jorgensen Charles R. , Landau Bernard R. , Wilson T. Hastings
Published: December 2017

The competition between different sugars for the transport mechanism of hamster small intestine was tested with an in vitro method which allowed the use of a single segment of intestine for both control and experimental periods. The transport of the test sugar d-galactose was inhibited by other sugars known to be actively absorbed by the intestine; namely, d-glucose, α-methyl-d-glucoside, i-deoxy-d-glucose, 6-deoxy-d-glucose and 3-o-methyl-d-glucose. On the other hand d-mannose and d-xylose, two sugars not actively transported, did not inhibit d-galactose absorption. In addition, sugars known to be actively absorbed produced an inhibition of transport of d-glucose and 6-deoxy-d-glucose when these were selected as test sugars. The results of these experiments are consistent with the view that all transported sugars compete for a common pathway in hamster intestine. Various hypotheses of sugar transport are discussed in light of the present data.
Potassium efflux from isolated rabbit heart into a potassium-free solution
Authors: Humphrey E. W.
Published: December 2017

The efflux of potassium from the isolated perfused rabbit heart into a potassium-free solution has been calculated from the zero time slope of the washout curve and the initial potassium concentration. It was found that this efflux very closely approximated that calculated from the K42 equilibration curves. Increasing the calcium content of the perfusate twofold had no significant effect on the outflux of potassium.
Effect of insulin and poisons on glucose uptake of sheep and goat placenta
Authors: Battaglia Frederick C. , Meschia Giacomo , Blechner Jack , Barron Donald H.
Published: December 2017

The basal glucose uptake of the cotyledons of sheep and goats was found to be 1.44 ± 0.09 mg/gm/hr.; that of the fetal chorion to be 2.22 ± 0.11; and that of the maternal uterine mucosa to be 2.05 ± 0.16 mg/gm of tissue/hr. The tissue was obtained from pregnant animals between 45 and 55 days gestation. Insulin, at a concentration of 100 mu/ml, has no effect on net glucose utilization of any of these tissues. Nitrogen and cyanide both increased the basal uptake of cotyledons by approximately 70%. Phlorizin was shown to inhibit both the basal uptake of glucose and the cyanide-accelerated uptake of glucose.
Effect of exposure duration on selected enzyme indexes of cold acclimatization
Authors: Hannon John P. , Vaughan David A.
Published: December 2017

Relative liver mass and liver activities of glucokinase, glucose-6-phosphatase, malic dehydrogenase and rate of pyruvate formation from 3-phosphoglycerate were measured in rats exposed to cold (4° ± 1°C) for periods of 2 days, 4 weeks and 5 months. The resultant data indicated the metabolic, cold-acclimatization process, insofar as the liver was concerned, consisting of three consecutive, but overlapping, stages. The first (as indicated by glucose-6-phosphatase activity) was an increased capacity to form blood sugar. This was evident after 2 days in the cold and persisted throughout all exposures. The second stage was an elevated heat-producing capacity per unit of liver weight. This was reflected in 4-week cold-exposed animals by an increased glucokinase, malic dehydrogenase and pyruvate formation rate. The third stage appeared between 1 and 5 months after entrance into the cold. It consisted of a regression of certain of the elevated activities per unit weight of liver and their replacement, insofar as the animal as a whole was concerned, by an increase in relative liver mass.
Anemia of rabbits fed a cholesterol-containing diet
Authors: Pinter Gabriel G. , Bailey Robert E.
Published: December 2017

The anemia developed by rabbits fed a cholesterol-containing diet seems to be of the hemolytic type. A striking increase in reticulocyte count, the appearance of nucleated red cells of different maturity in the peripheral circulation, anisocytosis, anisochromia and erythrocytes with punctate basophilia are characteristic findings on stained films and are the first symptoms of the progressing anemia. The red cell count decreases and reaches the lowest level at about the 8th–12th week of exposure of the animals to cholesterol. Cr51 survival studies revealed a shortened T 1/2:3.7 days compared to 12 days, which is the established normal value under our conditions. The results of cross-transfusion studies are interpreted as the indication that the anemia is developed as the consequence of the production of red cells with decreased resistance.
Survival of transfused blood in rats
Authors: Thompson John S. , Gurney C. W. , Hanel Arno , Ford Elizabeth , Hofstra Diana
Published: December 2017

Using the survival of transfused radioactive hexavalent sodium chromate (Na2Cr51O4)-labeled red cells as a criterion, the survival of rat blood in autologous animals and in animals of the same and another strain of rats was studied. It was found that blood from the Long-Evans strain was rapidly destroyed in Sprague-Dawley recipients and that this accelerated destruction was dependent on the presence of Bartonella muris infestation endemic to the Long-Evans strain. The infestation does not appear to affect survival of autologous red cells in carrier Long-Evans rats. Although the survival of blood from either homologous Sprague-Dawley or Long-Evans rats free from Bartonella muris infestation was reduced in normal Sprague-Dawley rats, splenectomy of Sprague-Dawley recipients resulted in an increase of survival time to above normal levels. Splenectomy of the recipient was also found to minimize the rapid destruction of Bartonella-free Long-Evans blood in ‘hyperimmunized’ Sprague-Dawley rats. The importance of the spleen in determining the fate of a homologous transfusion is discussed.
Difference between plasma and red cell flow characteristics of pulmonary vascular bed
Authors: Parrish Daniel , Strandness D. E. , Bell John W.
Published: December 2017

In open-chested, anesthetized dogs the pulmonary artery and pulmonary vein were catheterized and simultaneous dye dilution curves were obtained for Cr51-tagged red cells and I131-tagged plasma. The curves were analyzed by electronic analogue computer techniques to obtain pulmonary transfer characteristics. Typical results are shown and a possible explanation of their significance is presented. Mean transit times for cells and plasma were calculated and the ratio cell/plasma transit time was found to be .91 ± .05 (P < .001), a value significantly lower than that usually reported for the ‘central circulation.’ The difference results from the more peripheral sampling sites used by other investigators.
Hypothermia and minimal gradient requirements for excitation of cardiac muscle
Authors: Ushiyama J. , Brooks C. McC.
Published: December 2017

A method is described for testing the stimulating-effectiveness of linearly rising current. It was found that cardiac muscle, like nerve fibers, spinal neurons and skeletal muscle has a minimal gradient requirement. Dog trabecular muscles showed great differences in their minimal gradients even at the same temperature but the requirements of individual muscles were rather constant. During hypothermia (24°–27°C) there was a reduction in threshold to stimulation by a rectangular pulse and a great prolongation of the minimal gradient requirement for stimulation as though a type of accommodative reaction present at normal temperatures had been suppressed. Determination of minimal gradient requirements by exponentially rising current gave the same results as obtained with linearly rising currents. Excitation occurred when the rheobasic strengths, as determined by rectangular pulses of long duration, were attained if stimuli satisfied the minimal gradient requirement. The likelihood that a number of accommodative processes occur in tissues subject to stimulatory forces is discussed.
Effect of stimulation on phosphorylase levels of excised anterior tibial muscles of the mouse
Authors: Rulon R. R. , Schottelius D. D. , Schottelius B. A.
Published: December 2017

The effect of electrical stimulation on the activation of phosphorylase in mouse muscle was investigated. Rapid interruption of chemical events was accomplished by simultaneously quick-freezing resting and stimulated paired muscles. Phosphorylase ( a/t) ratios (%) were found to be significantly increased after 1 1/2, 3, 15, and 30 sec of stimulation; the increase was not significant after 1/2 sec. The present study shows that phosphorylase is activated with sufficient priority to bring about increased rates of glycogenolysis relatively early during the tetanic contraction of mouse muscle.
Changing size, composition, and contraction strength of gastrocnemius muscle
Authors: Schwartz Neena B.
Published: December 2017

Gastrocnemius-soleus muscle weight, length, water and nitrogen content, active and passive length-tension curves, and twitch and tetanic tensions were measured in normal male rats 24–131 days old. Mathematical analyses of the data were performed in order to determine appropriate factors to correct these variables for increasing body size and also to detect changing relationships among variables within the course of normal growth. Muscle weight is an increasing proportion of body weight, whereas muscle length grows at an ever-decreasing rate. Water is a decreasing, and nitrogen an increasing, proportion of muscle weight during growth. Length-tension relationships are quite unchanging over the measured span. Contraction strength is in constant ratio to wet muscle weight throughout the age range, but is higher on the basis of dry weight or nitrogen content in younger than in older rats.
Absorption of thiamine from intestine of dog
Authors: Da Silva A. C. , Ivy A. C.
Published: December 2017

A chronic Thirty fistula of the jejunum and ileum was prepared which permitted repeated quantitative studies to be made on the absorption of various substances. Dogs weighing an average of 20 kg had an average intestinal capacity to absorb approximately 22 mg of thiamine per day, when the daily oral intake was 40 mg. Thiamine was not destroyed when incubated for 12 hr in vitro with the normal saline wash of a Thiry loop of the jejunum or ileum. It was mechanically possible to recover all the thiamine introduced into the Thiry loops within 30–60 sec after its introduction. The same amount of thiamine was absorbed from the jejunum and ileum, respectively, during 1 hr. In nine daily tests an average of 3.2 mg or 30% (range 18–40%) of 10 mg of thiamine in 20 ml of normal saline was absorbed in 1 hr, the loops being 25–30 cm long. When 20 ml of an aqueous solution containing 0.7% Na2SO4, 0.45% NaCl, and 0.1% glucose was introduced for 30 min, the ileal and jejunal loops absorbed all the glucose. The ileal loops absorbed 34 mg or 38% of chloride expressed as NaCl, whereas the jejunal loops apparently added chloride.
Adipose tissue metabolism of obese mice on standard and high-fat diets
Authors: Lochaya Serene , Leboeuf Nicole , Mayer Jean , Leboeuf Bernard
Published: December 2017

Adipose tissue metabolism in vitro was studied, after substitution for several weeks of synthetic low-carbohydrate, high-fat (saturated or unsaturated) diets for the standard chow diet, in obese hyperglycemic mice and in their nonobese littermates. In tissue from nonobese mice fed the high-fat diets, glucose metabolism to CO2 and to fatty acids was diminished in the absence of added hormone, while glucose carbon incorporation to glyceride-glycerol was increased. Under insulin (0.1 unit/ml) stimulation, total glucose uptake was relatively decreased by the diets, as was glucose metabolism to CO2, to fatty acids, and to glycogen; however, glucose carbon incorporation to glyceride-glycerol was unaltered. Under epinephrine stimulation, the sum of glucose carbon recovery was less after high-fat feeding. No effect of high-fat feeding was detected on base-line rates of free fatty acid release nor on the effects of insulin or epinephrine on this process. No differences were found between the effects of saturated- or unsaturated-fat diets on any parameters. The metabolism of adipose tissue from obese mice was slightly, if at all, affected by high-fat feeding. These results are discussed in reference to the normal adaptation to low-carbohydrate, high-fat diets and to the metabolic abnormalities present in obese hyperglycemic mice.