bluuebunny/crossref_metadata_2025 huggingface dataset:
Malonate and fluoride effects on metabolism and contraction of electrically stimulated heart strips
Authors: Rice Leslie I. , Berman David A.
Published: December 2017

The effect of malonate and fluoride on the oxidation of C14-labeled substrates by electrically stimulated rat heart strips was investigated in an apparatus which permitted simultaneous recording of oxygen consumption and contractile activity. Malonate stimulated the force of contraction when glucose was the substrate, but not in the presence of pyruvate. Malonate had no significant effect on the rate of oxidation of glucose-1-C14, glucose-6-C14 or pyruvate-2-C14, indicating that its effect on contraction was not related to a) stimulation of glucose metabolism, b) inhibition of the Kreb's cycle, or c) stimulation of the phosphogluconate pathway. Malonate-2-C14 was oxidized by the ventricle strips, and the possibility exists that utilization of malonate as a substrate may account, at least in part, for its stimulation of contraction. The stimulation of contraction by fluoride was accompanied by significant alterations in metabolism. The oxidation of glucose and acetate was inhibited, whereas pyruvate oxidation was stimulated; these findings were interpreted in terms of known actions of fluoride on enzyme systems.
Anticoagulant action of TAMe and AFIF
Authors: Triantaphyllopoulos D. C.
Published: December 2017

The effect of addition of the anticoagulant fraction of incubated fibrinogen (AFIF) or tosylarginine methylester (TAMe) into mixtures of fibrinogen and thrombin was studied. It was found that although TAMe was able to inhibit coagulation when added prior or shortly after thrombin, it acted as procoagulant when added later. These procoagulant properties seemed to depend on the concentration and time of addition of TAMe. The amount of fibrinogen clotted increased with the time interval between the addition of thrombin and that of TAMe. AFIF acted exclusively as anticoagulant, being effective when added during the first two-thirds to five-sixths of the expected thrombin time. Whenever TAMe was added to mixtures of fibrinogen, AFIF, and thrombin, its procoagulant effect was delayed or altogether abolished depending on the time of addition. When, however, TAMe was added to mixtures of fibrinogen and thrombin together with AFIF its procoagulant action appeared unimpaired. Although TAMe delayed only the beginning, AFIF seemed to delay both the beginning and general course of polymerization.
Effect of ovulation and early gestation on oviduct secretions in the rabbit
Authors: Mastroianni Luigi , Wallach Robert C.
Published: December 2017

A system for continuous, volumetric collection of oviduct secretions was applied to New Zealand White rabbits. After 3 or more days, animals were mated. The secretion rate decreased on the 2nd and 3rd days of pregnancy. It leveled off at about 50% of the estrous rate and then remained steady during the succeeding 7 days. A similar decrease in rate was observed in pseudopregnancy. No decrease was observed in animals that rejected the male or in one that mated but failed to become either pregnant or pseudopregnant. The sodium concentration was significantly lower in the first 3 days of pregnancy (mean 142.6 mEq/l.) than in estrus (mean 144.5 mEq/l.). A significant change in potassium (mean 6.2 mEq/l.) and chloride (mean 118.7 mEq/l.) levels was not demonstrated. The reducing sugar content (mean 6 mg %) displayed no variation in relation to ovulation. Glycine, glutamic acid, alanine, valine and leucine were consistently present. The lactic acid concentration varied widely among the animals (range 4.4–51.0 mg%). In the group, it was increased significantly in early pregnancy.
Protection of the fetus in experimental potassium depletion
Authors: Stewart Edwin L. , Welt Louis G.
Published: December 2017

Pregnant rats were provided with a potassium-deficient diet on the day of mating. One group was sacrificed at 12–13 days of gestation and another group at 21 days. A third group was depleted of potassium acutely by utilizing peritoneal dialysis with an isotonic NaHCO3 solution. In all groups maternal serum and muscle potassium were found to be significantly lower and maternal serum CO2 significantly higher in the experimental animals than in the controls. However no significant difference in total fetal potassium concentrations was found when experimental and control animals were compared. As late as 15–17 days of gestation the total fetal potassium concentrations were found to be nearly double those of maternal skeletal muscle, but on day 21 the total fetal and the maternal muscle values were roughly equivalent. The mean dry weight of the experimental 21-day fetuses was significantly lower than that of the control fetuses. The mechanism of fetal sparing in maternal potassium depletion cannot be determined from the present data.
Blood volume, corpuscular constants, and shell weight in turtles
Authors: Hutton Kenneth E.
Published: December 2017

In a group of 11 red-eared turtles, Pseudemys scripta elegans, ranging from 258 to 1827 gm, it was found that body size did not produce variations in packed cell volume, hemoglobin concentration, or in Wintrobe corpuscular constants derived from these values. A small inverse correlation of shell weight with body weight was noted. Blood volume, determined by cardiac injection of iodinated (I131) albumin and expressed as percentage of body weight, showed a strong inverse correlation with body weight.
Effect of chlorpromazine on blood level of alcohol in rabbits
Authors: Tipton Dale L. , Sutherland V. C. , Burbridge Thomas N. , Simon Alexander
Published: December 2017

It was previously observed in man that chlorpromazine elevated the blood alcohol level above that expected after a standard dose of ethanol. The present study shows a similar elevation of blood alcohol in rabbits; furthermore, this elevation occurs whether the ethanol is given orally or intravenously. The magnitude of the elevation is less with intravenously administered alcohol. Since an increased absorption rate might explain this difference in magnitude, a detailed analysis of factors influencing absorption was done. Since chlorpromazine inhibits the sympathetic nervous system centrally and the parasympathetic peripherally, other autonomic blocking agents were studied for their effects on the blood alcohol level: reserpine was used for central sympathetic inhibition, atropine for peripheral parasympathetic inhibition, and hexamethonium for dual inhibition. Since none of these agents affected the blood alcohol level, nor did chlorpromazine elevate the blood level of other substances absorbed in a manner similar to ethanol, it was concluded that no part of the effect was due to an increase in absorption but that the effect probably was due entirely to an inhibition of metabolism.
Changes in blood constituents in sheep after thyroidectomy
Authors: Hackett Patricia L. , George Lynn A. , Barnes Charles M. , Bustad Leo K.
Published: December 2017

Blood values for protein-bound iodine, creatinine, phosphorus, urea nitrogen, cholesterol, calcium, leukocytes, hemoglobin, and hematocrit in surgically thyroidectomized Suffolk sheep were compared with control animals' levels for 1 year. Serum protein-bound iodine values were found to decrease and creatinine to increase immediately after surgical thyroidectomy. Lymphopenia developed during the second postsurgical month, and inorganic phosphorus was elevated during the last part of the experimental period. No significant changes occurred in calcium, hemoglobin, hematocrit, or neutrophil values.
Age changes in blood of the golden hamster
Authors: House E. L. , Pansky B. , Jacobs M. S.
Published: December 2017

Studies were made on 500 male hamsters, ranging in age from 4 weeks to 1 year. Significant changes from the initial values of blood parameters established in the 4-week-old hamster were the following: a) neutropenia and lymphocytosis at 8 weeks with a return to the basic values by 1 year; b) sustained elevation of hematocrit values beginning at 8 weeks; c) a small increase in hemoglobin, persistent after 8 weeks; d) gradual decline in albumin during the 1st year; e) an elevation of the alpha-2 globulin by the 6th month; f) a decreased beta globulin beginning at 8 weeks; g) alternating increase, decrease, and increase of the gamma globulin-fibrinogen factor, at 8 weeks, 6 months, and 1 year, respectively; h) a decline in the A/G (albumin/globulin) ratio with increasing age; i) an increase in the albumin lipoprotein and a drop in the beta-gamma lipoprotein with advancing age. The fibrinogen of hamster plasma was linked to gamma globulin.
Biliary excretion of inulin, sucrose, and mannitol: analysis of bile formation
Authors: Schanker Lewis S. , Hogben C. Adrian M.
Published: December 2017

The transfer between blood and bile of three large, inert, water-soluble molecules was investigated in the rat. At the steady state, the bile:plasma concentration ratios were: inulin, 0.1; sucrose, 0.2; and mannitol, 1.2. Since these substances invade substantial hepatic spaces, 24–72% of the wet tissue weight depending on the size of the molecule, the permeability to large, lipid-insoluble molecules appears to be a feature of the hepatic parenchymal cell membrane. Kinetic analysis of the steady-state distribution of sucrose between liver, bile and plasma suggests that two boundaries of the hepatic parenchymal cell, the one which separates the cell interior from plasma, and the one which separates the cell interior from bile, may be equally permeable to sucrose.
Renal tubular transport of inorganic sulfate
Authors: Globus David L. , Becker E. Lovell , Thompson David D.
Published: December 2017

The urinary excretion of radiosulfate by the dog was investigated after a rapid injection into one renal artery. Radiosulfate appeared in the urine before simultaneously injected creatinine. After the plasma sulfate concentration had been elevated, the precession of sulfate over creatinine disappeared. Glucose infusion, which competes with sulfate reabsorption, decreased precession; phlorhizin, which blocks glucose transport, increased the precession. In the chicken, compounds injected into a leg vein perfuse only the tubules of the ipsilateral kidney on the first circulation. Before and after sulfate loading, precession of radiosulfate was seen, and the influx of sulfate increased after loading. There was no consistent relationship between the increase in the plasma sulfate concentration and the increase in influx. The proportion of excreted sulfate which entered the urine by transtubular flux decreased with the increase in the plasma sulfate concentration. This may explain the diminished precession of radiosulfate seen in the dog after loading with sulfate.
Effect of substrates on potassium accumulation by rabbit kidney cortex
Authors: Berndt William O. , LeSher Dean A.
Published: December 2017

Slices of rabbit renal cortex were depleted of potassium by leaching for 30 minutes in 0.15 m sodium chloride solution. The ability of various substrates to promote reaccumulation of potassium was studied by incubating the leached slices with substrate at 37.5 C in a K-rich medium. Of the ten substrates studied, glutamate, glutamine, and α-ketoglutarate supported K uptake best, permitting the tissue during 40 minutes of incubation to attain K concentrations almost equal to the concentrations in fresh tissue. Glucose was comparable to the above three substrates at 40 minutes, but the initial rate of uptake was slower. With fumarate, oxalacetate, malate, and succinate the K uptake was not significantly greater than in experiments where no substrate was employed. Citrate and aspartate supported K uptake better than no substrate, but not as well as glutamate, glutamine, and α-ketoglutarate. When α-ketoglutarate was used as the substrate the addition of magnesium improved the K uptake. The relationship between K uptake and Na extrusion is discussed.
Source of ammonia excreted by the gills of the marine teleost, Myoxocephalus scorpius
Authors: Goldstein Leon , Forster Roy P.
Published: December 2017

Measurement of ammonia concentration differences in blood entering and leaving gills showed that only about 12% of branchially excreted ammonia could be accounted for by the disappearance of blood ammonia. Gill tissue homogenates contained significant glutaminase I and glutamic acid dehydrogenase activities. The combined activity of both enzymes was more than sufficient to account for the branchially excreted ammonia. Furthermore, there was a significant deamination of blood glutamine by gill tissue. Thus, it is likely that the ammonotelism of teleosts is due to the enzymatic deamination of glutamine and other amino acids in the gill.
Humoral factors released from intracranial sources during stimulation of reticular formation
Authors: Sharpless Seth K. , Rothballer Alan B.
Published: December 2017

Previous work has suggested that catecholamines might function as transmitter substances in portions of the reticular activating system. In this study, we used classical autopharmacological methods in an effort to detect catecholamine release into the systemic circulation of the encéphale isolé preparation during stimulation of the reticular formation. Fluctuations of blood pressure and movements of the denervated nictitating membrane were observed after exclusion of effects mediated by the cranial nerves and sympathoadrenal discharge. Since these effects were not blocked by Dibenzyline, and could be reproduced by small doses of Pitressin, they were ascribed to the release of vasopressin from the neurohypophysis rather than to catecholamine release. Some preliminary data were obtained on the localization in the midbrain of a pathway that appears to influence the hypothalamoneurohypophysial system, and that may possibly be responsible for the antidiuretic effects of pain and emotional excitement.
Reflex chemoceptive excitation of diencephalic sham rage behavior
Authors: Bizzi E. , Libretti A. , Malliani A. , Zanchetti A.
Published: December 2017

In acute thalamic cats, excitation of the carotid body chemoceptors was induced by intrasinusal injection of lobeline (10 µg) or by administering low oxygen mixtures (5–12% O2 in N2). Bilateral section of the cervical vago-aortic trunks, preliminary to the experiment, permitted the exclusion of the aortic chemoceptive areas from our study. Stimulation of the carotid body chemoceptors was constantly capable of evoking sham rage outbursts identical in pattern and intensity to those induced by tactile or noxious stimulation or occurring spontaneously. When low-intensity stimulation was used (10–12% O2) the rage fits were preceded in time by signs of excitation of the medullary respiratory and vasomotor centers. Since lobeline and hypoxia became unable to evoke sham rage outbursts following selective inactivation of the carotid body chemoceptors it is concluded that the diencephalic mechanisms for rage behavior are within the sphere of influence of chemoceptive reflexes.
Electromyography of experimentally immobilized skeletal muscles in cats
Authors: Fudema John J. , Fizzell James A. , Nelson Edward M.
Published: December 2017

The hind limbs of ten cats were bilaterally immobilized by external fixation without altering skeletal muscle innervation. Bilateral immobilization was used to rule out the possible effects of reciprocal activation from a nonimmobilized contralateral limb. Limbs were fixed in a neutral position to minimize the effect of muscle spindle activation. An electromyograph with an integrator circuit was used to measure the maximum action-potential output of anterior tibial muscles of both sides. Recordings were made of the maximum integrating meter response of the muscles to a standardized supramaximal electrical stimulus applied percutaneously to the common peroneal nerve while the animals were uniformly anesthetized. Measurements were made every 4 days for a period of 101 days of immobilization. The control or normal response was represented by measurements made at the beginning of the experiment. A highly significant continuing decrease in electrical output of the skeletal muscles was seen during the course of the immobilization. No statistically significant difference was found between the response of the right and left sides.
Glycogen mobilization and work in the rat heart
Authors: Hazelwood Robert L. , Ullrick William C.
Published: December 2017

Glycogen mobilization was studied in isolated rat heart trabeculae carneae stimulated to contract isometrically. Glycogen content of stimulated and nonstimulated muscle preparations was determined, as was glucose content of the fluid bathing the muscles. Isometric twitch curves were integrated over periods of stimulation and the results, in milligram seconds of tension time, used as an index of work performance. Relationships between work performance, 48-hr fasting, hypophysectomy, and mobilization of glycogen were investigated. The amount of glycogen mobilized by the isolated tissue was correlated with initial glycogen content but not with work performance. There was no correlation between initial glycogen content and work done by the tissue. These experiments indicate that the isolated cardiac muscle preparation relies on substrate(s) other than carbohydrate as an immediate source of energy. Heart preparations from 48-hr fasted and from hypophysectomized animals showed significantly greater work performance than did preparations from normal animals, but depletion of glycogen stores again appeared to be related to initial glycogen content and not to work done.
Structure and concentrating mechanism in the mammalian kidney
Authors: Schmidt-Nielsen Bodil , O'Dell Roberta
Published: December 2017

In a number of mammalian kidneys a close correlation was found between renal medullary thickness and ability to concentrate electrolytes in the urine, indicating that both outer and inner zone of the medulla act as a countercurrent multiplier system. Further evidence for this assumption was furnished through studies of the distribution of urea and electrolytes in different kidney types during antidiuresis. The beaver with 100% short-looped nephrons, the rabbit with 44% long-looped nephrons, and the desert rodent Psammomys with 100% long-looped nephrons were studied. In all three kidney types sodium and urea concentrations increased to approximately the same level in the outer zone of the medulla. In the rabbit and Psammomys kidneys a considerable increase in sodium concentration was found through the inner zone of the medulla. This can best be explained if we assume that the sodium pump, which has been demonstrated in the thick ascending limb of the loop of Henle, functions in a similar manner in the thin limb.
Electrical and mechanical activity of myocardium in mice with muscular dystrophy
Authors: Kleinfeld Morris , Magin John , Murphy Bernard , Stein Edward
Published: December 2017

The intracellular potential and maximum tension output of the atrial and ventricular myocardium of dystrophic mouse, strain 129, developed at Jackson Memorial Laboratory, showed no significant differences from normal littermate. Histological sections of these tissues stained by hematoxylin and eosin revealed no morbid changes. By contrast, the gastrocnemius muscle of the dystrophic strain revealed a significantly decreased maximum tension output and marked prolongation of the relaxation period when compared to that of a normal mate. Histological sections of the gastrocnemius muscle of the dystrophic mate showed variable degrees of morbidity. The absence of significant differences in the electrical and mechanical parameters of the myocardium in the normal and genetically dystrophic littermate indicates that the myopathic process spares the cardiac muscle. This is at variance with the picture seen both in rats reared on a prolonged vitamin E deficient diet and in the progressive form of human muscular dystrophy where morbid changes involving the myocardium are rather frequent.
Vasotropic substances in blood in intestinal ischemia shock
Authors: Baez S. , Hershey S. G. , Rovenstine E. A.
Published: December 2017

Serial, simultaneous rat mesoappendix assays of portal, hepatic, and femoral vein plasma in dogs in SMA shock (temporary ligation of the superior mesenteric artery) indicated the elaboration of an epinephrine inhibiting (eI) substance which appeared first in the portal vein. In dogs protected by intraportal vein injection of Dibenzyline, after onset of intestinal ischemia, an eI response was observed only in the portal vein, from which it disappeared within 8 hr. In vitro incubation of eI plasma with antiferritin serum inactivated the vasoinhibitory effects of most samples. Assay of shock plasma on the isolated rat gastric muscle strip elicited contractile responses. Pre-exposure of the muscle strip to BOL-148, a serotonin antagonist, attenuated this response. These myogenic effects were not altered by antiferritin serum or atropine. A progressive fall in plasma-bound iron levels was found in SMA portal blood. These findings establish the intestinal origin of vasotropic material in SMA shock. This material exhibits the vasotoxic properties of ferritin and the myogenic properties of serotonin.
Physical and metabolic factors in diffusion of solutes into tissue slices
Authors: Cascarano Joseph , Zweifach Benjamin W.
Published: December 2017

Although the physical factors influencing the diffusion of solutes (such as oxygen) into tissue slices have been clearly defined, conflicting results obtained with this approach indicate that certain of the necessary considerations are not being satisfied. The application of histochemical procedures, such as the tetrazolium technique, to the study of fresh tissue slices provides a means of exploring directly some of the complexities involved since the actual depth of penetration of the solute can be determined by histological inspection. The penetration of tetrazolium salts was found to be influenced in a predictable manner by concentration and by tissue activity as could be anticipated from Warburg's formula governing the diffusion of solutes into tissue slices. The experiments demonstrate that the penetration of solutes (such as oxygen or tetrazolium salt) is frequently decreased under experimental conditions common to many metabolic processes and that quantitative measurements which do not take this factor into account could be in considerable error. In addition to illustrating the variables affecting the penetration of solutes, the tetrazolium salt studies demonstrate the usefulness of applying histochemical procedures to metabolic slice studies. An algebraic modification of Warburg's formula has been presented which provides a means of correcting quantitative data obtained on incompletely penetrated slices.
Failure of adrenergic and cholinergic blocking agents to block ovulation in the rat
Authors: Moore Ward W.
Published: December 2017

Mature Sprague-Dawley rats were used in a study of the mode of action of Dibenamine (30 mg/kg), Dibenzyline (10 mg/kg), and Pathilon (35 mg/kg) blockade of spontaneous ovulation-inducing hormone (LH) release. All three agents effectively blocked the release of LH if administered subcutaneously prior to the "critical period" on the day of proestrus (1:00 pm), but each failed to block the release of LH if administered at 5:00 pm on the day of proestrus. When each drug was administered daily at 5:00 pm, vaginal cycles were interrupted but returned to normal after 12–16 days' treatment. After such chronic treatment the animals were then treated with the drug at either 1:00 pm or 5:00 pm on the day of proestrus. A minimum of 80% of the animals released LH and ovulated normally in all six groups. Studies using adrenal ascorbic acid depletion indicate that the animals "adapt" to each drug within 9 days' treatment, and each drug retains its specific blocking properties. The results indicate that the drugs prevent LH release indirectly and not through their respective blocking properties. The findings suggest a reciprocal relationship between the release of LH in amounts which induce ovulation and the release of adrenocorticotrophic hormone (ACTH) following adequate stimulation.
Lipid transport and lipoprotein interconversions
Authors: Grundy Scott M. , Dobson Harold L. , Kitzmiller George E. , Griffin A. Clark
Published: December 2017

Serum lipoproteins were isolated from various sources including normal and hyperlipemic human, dog, and rabbit serum through preparative ultracentrifugation. These lipoprotein fractions were extracted with cold ether, and the ether-modified products were studied for sedimentation and flotation properties in an analytical ultracentrifuge. Results indicate that a relatively small number of ether-modified residues are obtained from the entire lipoprotein spectrum of all species studied. It is suggested that these moieties may be closely related to actual lipid-transporting components of the lipoprotein system. In addition, a fraction of lipoprotein-free human serum (probably closely related to beta globulin) has been identified, which will bind certain phospholipids. This protein-phospholipid complex may be separated from other serum proteins through ultracentrifugation and studied electrophoretically.
Metabolism of zinc-65
Authors: Rubini M. E. , Montalvo G. , Lockhart C. P. , Johnson C. R.
Published: December 2017

The absorption, deposition, and excretion of zinc65 was studied in mice, rats, and dogs. When zinc65 was fed to the animals it was poorly absorbed, but its long biologic half-life made even the small portion absorbed physiologically significant. Absorption was obviated by feeding large quantities of nonradioactive carrier zinc. Injected zinc65 chloride first was deposited, preferably in the pancreas, liver, and spleen, with only minor deposition in muscle and in the brain. Subsequently, a large proportion was transferred to bone. The chief means of excretion was in feces, presumably via pancreatic secretion. Injected nonradioactive zinc or treatment with 2,3-dimercaptopropanol (BAL), Versene, or cadmium ion failed to alter body burden significantly. Cadmium, however, decreased soft tissue zinc65 deposition and increased accretion by the skeleton. Blood activity fell rapidly and less than .01% of the dose injected remained in the blood after 1 day. Renal excretion of zinc65 rose as plasma concentration fell and clearance ratios in excess of 1.0 were noted, indicating probable renal secretion.
Brain electrolytes and cortical impedance
Authors: Harreveld A. Van , Hooper N. K. , Cusick J. T.
Published: December 2017

A 50% glucose solution was administered intravenously to rabbits at a rate of about 1 cc/min until death of the preparation. An analysis of the brain showed that besides water the tissue had lost a considerable amount of its chloride and sodium (20–25%). The amount of potassium in the brain remained practically constant. The cortical impedance increased markedly during the glucose infusion. These findings support the thesis that the compartment of the tissue containing the bulk of the chloride and sodium ions has a special significance for the cortical impedance.
Effect of serotonin, epinephrine, histamine, and hexamethonium on thoracic duct lymph
Authors: Shim Walton K. T. , Pollack Eugene L. , Drapanas Theodore
Published: December 2017

Serial studies of thoracic duct lymph flow rates and lymph proteins including albumin, globulin and fibrinogen were performed in 22 fasting unanesthetized dogs following intrathoracic cannulation of the thoracic duct with a polyethylene catheter. Serotonin given intravenously (20 µg/kg/min) produced a marked increase in lymph flow (115%) with a 20% decrease in total protein concentration. A single intravenous injection of epinephrine (1 mg) produced a 92% increase in lymph flow accompanied by a 12% increase in protein concentration. Histamine (1 mg) given intravenously also produced a significant increase in lymph flow (127%) but protein concentration remained constant. Hexamethonium chloride (2.5 mg/kg iv) markedly depressed lymph flow rate (50%) without significantly altering lymph protein concentrations. The possible mechanisms of action of each of these agents is discussed. Results indicate that serotonin markedly influences lymph production and lymph protein concentration by a probable selective alteration of capillary permeability rather than by increasing intestinal motility.
Ionic composition of red cells in fetal, newborn, and adult sheep
Authors: Blechner Jack N.
Published: December 2017

The concentrations of Na and K in the erythrocytes of the blood of adult, purebred Dorset ewes and their fetuses were determined by flame photometry. With respect to these cations, adult ewes can be divided into two groups; in one, Na is in higher concentration and, in the other, K concentration is higher. In every fetus studied, however, the K concentration exceeded the Na, and there was a higher K and a lower Na concentration than in the maternal erythrocytes. In lambs of mothers with a high Na concentration in their erythrocytes, the transition from the fetal to the adult electrolyte pattern was completed 7 or 8 weeks post partum. The relationship between the ionic composition of the red cells and the O2 dissociation curves in mothers and their fetuses, and in both groups of adult sheep, is discussed. Differences in the concentrations of Na and K in the erythrocytes do not appear to explain the differences in O2 dissociation curves observed among adult sheep.
Distensibility of the dog left ventricle
Authors: Hefner Lloyd L. , Coghlan H. Cecil , Jones William B. , Reeves T. Joseph
Published: December 2017

Left ventricular diastolic pressure-circumference curves were determined in 13 dogs, during stepwise hemorrhage and transfusion of blood. The linearity and small amount of scatter in the pressure-circumference curves obtained during control circumstances is evidence that elasticity rather than viscosity or inertia is the dominant determinant of the curve. Coincident with the slow infusion of epinephrine the distensibility increased. The importance of viscosity and inertial effects in the myocardial wall may also have increased, as evidenced by the increased scatter of the pressure-circumference graph. The magnitude of the change in distensibility observed was great enough to produce large changes in ventricular performance at a given filling pressure.
Effect of epinephrine and norepinephrine on coronary vascular resistance in dogs
Authors: Hardin Robert A. , Scott Jerry B. , Haddy Francis J.
Published: December 2017

The effects of intracoronary injection and infusion of epinephrine and norepinephrine have been studied in the beating and fibrillating dog heart. The heart performed no external work and coronary perfusion pressure was measured with the rate of blood flow through the coronary vascular bed held constant. Injection of both agents most often produced a fleeting rise in pressure followed by a prolonged fall in pressure. In the beating heart, the pressure rise preceded rise in heart rate. Slow infusion of norepinephrine often produced a small pressure rise whereas rapid infusion always produced a large pressure fall. Epinephrine sometimes produced similar changes but more often the pressure fell progressively as a function of the rate of infusion. The pressure rise frequently was unassociated with a change in heart rate or the proportion of a minute spent in systole. Both parameters, as well as oxygen consumption, increased with high rates of infusion. These findings suggest that the direct effect of these agents on coronary vessels is active constriction, whereas the indirect effect is active dilatation. In low concentrations the direct effect may predominate, resulting in a resistance increase, whereas in high concentrations the indirect effect always predominates, resulting in a decrease of resistance.
Creatine, creatinine, and creatine phosphate in normal and hypertrophied rat hearts
Authors: Gangloff E. C. , Hemmings I. L. , Krause R. F.
Published: December 2017

Cardiac hypertrophy was produced in adult, male, albino rats by exercise. A highly significant increase in creatine phosphate and percentage of creatine as creatine phosphate in cardiac hypertrophy was demonstrated. No significant differences were detected in creatine or creatinine concentrations.
Pulmonary and systemic blood pressure response to serotonin: role of chemoreceptors
Authors: Braun K. , Stern S.
Published: December 2017

Large doses of serotonin (200 µg/ kg) in the anesthetized open-chest dog, administered into the femoral vein, right heart, pulmonary artery, left heart, ascending aorta or common carotid arteries, caused a marked pressor response in the systemic circulation. The latent period became shorter with the shift of the site of the injection toward the ascending aorta. After injection into the descending aorta a "double peak" pressor response was obtained. These observations, together with the demonstration of a much less pronounced pressor effect after elimination of the aortic and carotid chemoreceptors, indicate participation of chemoreceptor stimulation in the systemic pressor response. In the pulmonary artery the pressure rose markedly and consistently. A rise in the pulmonary venous pressure without any significant change in the left atrial pressure was observed, indicating pulmonary venous constriction. Chemoreceptor stimulation was shown to play a part also in the rise of both the pulmonary arterial and pulmonary venous pressures.
Normal blood clotting of inbred mice
Authors: Meier Hans , Allen Robert C. , Hoag Warren G.
Published: December 2017

Normal values for a variety of coagulation tests were comparable regardless of strains of mice or sex, suggesting lack of physiologic variation in factors, e.g., "antithromboplastins," inhibitors, etc. Units of mouse prothrombin per milliliter are only about one-half those of man; prothrombin is rapidly destroyed after coagulation, and in order to obtain consistent clotting of recalcified plasma, admixture of platelet factor reagent is necessary.
Cardiovascular conditioning in dogs
Authors: Mack Robert L. , Davenport Othel L. , Dykman Roscoe A.
Published: December 2017

Comparative data on heart rate, blood pressure, and motor response in dogs, indicate that cardiovascular conditioning as exhibited by heart rate and blood pressure changes is more reliable than motor conditioning. While blood pressures obtained by the ausculatory method are equivalent to those obtained by the direct method in intact dogs, the former may lead to certain errors in the interpretation of conditioning results because of the time required to secure accurate readings.
Effect of hypoxia on sympathoadrenal activity in dogs with myocardial insufficiency
Authors: Toyooka Edward T. , Blake William D.
Published: December 2017

This study was undertaken to determine if a mild circulatory stress (hypoxia) caused a greater than normal activation of the sympathoadrenal system in dogs with cardiac insufficiency. Plasma concentration and urinary excretion of epinephrine and norepinephrine were used as indices of sympathoadrenal activity. Hypoxic stress (breathing 8–10% O2) was applied to normal dogs and to the same animals after myocardial damage (coronary embolization) and after myocardial damage plus anemia. Only coronary embolization plus anemia produced overt evidence for cardiac insufficiency. None of the animals, either before or after induction of cardiac insufficiency, showed any significant increase in catecholamine output in response to hypoxia. Ability of the method to detect increased catecholamine concentration was validated by responses to carbamylcholine injection and acute hemorrhage. These results suggest that although the method will detect increased adrenal medullary secretion, it may not detect release of small quantities of norepinephrine from postganglionic neuroeffector junctions. Further, increased sympathetic nervous system activity in these dogs was insufficient to provoke adrenal medullary secretion.
Effect of 2,4 dinitrophenol on electrical and mechanical activities of isolated heart
Authors: Kleinfeld Morris , Magin John , Stein Edward
Published: December 2017

DNP (2,4 dinitrophenol) in concentrations of 2–5 x 10–5 m produced a shortened action potential duration (APd), a decrease in the magnitude of the AP, and a depression of contractility in the isolated perfused frog heart and the mouse atrium. There was a close correlation between the shortened APd and depression of contractility. The membrane resting potential was unchanged even during the period of cardiac arrest. The following mechanisms are postulated to explain the changes in cardiac activity induced by DNP: a) the enhanced repolarization (shortened APd) is attributed to an increase in membrane permeability to K+ associated with an enhanced K+ efflux; b) the decrease in the magnitude of the AP is ascribed either to an impaired active extrusion of Na+ or to a depression of the Na+-carrying system resulting in a decrease in Na+ influx; c) the depression in contractility is due to an interference with the transport, conversion, or utilization of ATP.
Regional blood flow and vascular resistance during hypothermia in dog
Authors: Westin Bjorn , Sehgal N. , Assali N. S.
Published: December 2017

Changes in regional blood flow and regional vascular resistance during hypothermia in dogs with intact or abolished shivering mechanisms were measured with sine-wave electromagnetic flowmeters. In animals with shivering intact, cooling produced a fall in renal and carotid blood flows, despite a rise or no change in cardiac output. The fall was caused by an increase in renal and carotid vascular resistances. Femoral blood flow increased because of a decrease in vascular resistance. In animals with shivering abolished, cooling evoked a fall in the cardiac output and in renal and femoral blood flows, due to an increase in the vascular resistance. Upon rewarming, femoral flow immediately rose to values far above control. Carotid flow increased during cooling because of a decline in carotid resistance. Such a decline might have been related to the elevated blood Pco2 observed in the nonshivering animals.
Lymphatic transport of selected nitrofuran derivatives in the dog
Authors: Buzard James A. , Conklin John D. , Buller Robert H.
Published: December 2017

By comparing drug concentrations in dog plasma and thoracic duct lymph, it has been shown that orally or intravenously administered nitrofuran derivatives cross the blood-lymph barrier and are transported in the lymphatic circulation. Investigation of a group of nitrofurans with widely differing physical properties indicates that the extent of plasma binding is a major factor in determining the apparent rate of transfer of these drugs to the lymph.
Effect of thyroid on gastric secretion and metabolism
Authors: Nasset E. S. , Goldsmith Dale P. J.
Published: December 2017

The effect of administration of thyroid products on gastric acid secretion and metabolism was studied in dogs with gastric pouches and in gastric mucosa from rats and frogs. Whole thyroid, thyroxin, triiodothyronine, and iodinated casein generally reduced secretion in thyroidectomized dogs and in dogs with intact thyroids. The thyroid substances elevated BMR above euthyroid levels in normal dogs but not always in thyroidectomized dogs. In dogs with intact thyroids 2,4-dinitrophenol raised oxygen consumption but did not affect secretion. Whole thyroid elevated BMR in rats and frogs but did not change resting mucosal oxygen consumption. During spring and early summer thyroid feeding reduced histamine-stimulated acid secretion and mucosal oxygen consumption during secretion in frogs, but the acid-to-oxygen ratio was unaffected. These findings suggest that elevated tissue concentrations of thyroid hormones reduce the ability of the gastric mucosa to mobilize secretory energy in response to a stimulus. This effect of the thyroid hormones is apparently not directly correlated with their calorigenic properties.
Effects of diet on serum lipids of fetal, neonatal, and pregnant rabbits
Authors: Friedman Meyer , Byers Sanford O.
Published: December 2017

The serum phospholipid, cholesterol, and triglyceride values of the fetal rabbit were determined and found to be significantly higher than similar values in the maternal host. Moreover, these fetal serum values could not be changed by altering the maternal blood lipid levels. The rise in serum cholesterol and phospholipid usually observed in the suckling rabbit could be prevented by omission of both triglyceride and cholesterol from its diet. The omission of cholesterol appeared to be most responsible for this phenomenon, because the omission solely of cholesterol from the diet of slightly older rabbits appeared capable of reducing their blood cholesterol from a level which had been elevated previously by their ingestion of cholesterol rich natural milk from lactating dams.
Calcium and strontium secretion from blood to milk
Authors: Twardock A. R. , Comar C. L.
Published: December 2017

The mechanisms of Ca and Sr secretion from blood to milk in goats were studied using varying combinations of one radioisotope of Ca and two radioisotopes of Sr and continuous, long-term intravenous infusions as a means of maintaining desired blood levels of stable and radioisotopes of the two elements. Calcium and Sr secretion from blood to milk was the same whether radionuclides were given orally or intravenously; the same was true for radiostrontium excretion by the kidney. Stable Ca infusions gave plasma Ca levels as high as 36 mg %, causing marked decreases in blood and milk levels of ingested Ca45 and Sr85 and reduced renal Ca-Sr discrimination; these results are explainable in terms of a flooding of the renal tubule with stable Ca. Stable Sr infusion gave blood plasma and milk levels as high as 4.6 mg % and 39 mg %, respectively; it caused no change in blood and milk levels of ingested Ca45 but increased levels of ingested Sr89 by a factor of two. The relative movement of Ca and Sr from blood to milk was unaffected by infusions. After stable Ca infusions, plasma stable Ca consistently dropped below preinfusion levels; this may have been due to depression of the parathyroids by high blood Ca. After injection into the mammary gland via the teat canal, equal amounts of Ca45 and Sr85 moved into the blood stream, which indicated the existence of a unidirectional mechanism for preferential movement of calcium over strontium from blood to milk.
Autonomic response to chronic electrode stimulation of cerebellum
Authors: Emerson J. D. , Bruhn John M. , Emerson Geraldine M. , Foley J. O.
Published: December 2017

The cerebellum was stimulated with implanted chronic concentric stainless steel electrodes in ten cats, with isolation of current to the cortex immediately beneath the electrodes. Stimulus parameters were: current density 0.5–2.55 ma/mm2, pulse duration 1–2 msec., frequency 100 cycle/sec, stimulus train duration 10–15 sec. Elevation of bladder pressure, pupillary dilatation, and pupillary constriction were obtained at P values of 10–7–10–10; depression of bladder pressure at P < 10–5. Responsive areas included ansiform lobule and vermis.
Experimental hyperthyroidism in dogs and effect of salivariectomy
Authors: Piatnek Dorothy A. , Olson Robert E.
Published: December 2017

A hyperthyroid state was induced and maintained in 17 dogs for 2–10 months by the administration of massive amounts of thyroid hormone. The great tolerance of this species to such large doses was striking. The clinical signs characteristic of hyperthyroidism in other mammals were observed including significantly increased caloric intake, oxygen consumption, heart rate, and body temperature. The laboratory findings included polycythemia, markedly increased levels of protein-bound iodide (PBI), increased turnover rates of l-thyroxine, and a decreased urinary excretion of inorganic iodide. Unlike other species the hyperthyroid dogs did not demonstrate marked reductions in body weight or serum cholesterol. Salivariectomy neither hastened nor enhanced the onset of exogenous hyperthyroidism in the dog. Measurements of the rate of disappearance of I131 l-thyroxine from the plasma and the rate of appearance of radioactive iodide in the urine indicated that the salivary glands in the intact dog are effective sites of deiodination and iodide excretion. This activity, however, is not the sole regulator of the level of circulating thyroid hormone and thus of the thyroid state.
Ion association. VII. Dependence of calciuresis on natriuresis during sulfate infusion
Authors: Walser Mackenzie
Published: December 2017

Sulfate was infused intravenously into dogs as the salt of sodium, potassium, or the organic amine, "tris." Calcium clearance was more closely correlated with sodium clearance than with sulfate excretion. When sodium excretion was low, little calciuresis occurred. The clearance of free calcium ions was calculated, making allowance for the electrostatic association between calcium and sulfate ions in the urine. The relationship between free calcium ion clearance and sodium clearance closely resembled that previously observed during saline or mannitol diuresis. Thus, in the absence of hypercalcemia, calcium excretion in the dog, in these experiments, is dependent primarily on the simultaneous sodium excretion, which determines free calcium ion excretion, and secondarily on the concentration of complexing anions in the urine, which determines how much additional calcium is excreted in bound form.
Saluretic actions of neurohypophysial peptides in conscious dogs
Authors: Chan W. Y. , Sawyer Wilbur H.
Published: December 2017

The effects of arginine vasopressin, oxytocin and two synthetic analogues, arginine vasotocin (8-arginine oxytocin) and oxypressin (8-leucine vasopressin), on urinary electrolyte excretion were studied in conscious dogs. Arginine vasopressin, 0.25 mu/kg, evokes a consistent natriuretic response during water diuresis, while at low urine flows the natriuretic response is usually absent. Oxytocin, 6–7 mu/kg, produces consistent natriuresis only at low urine flows. In higher doses, however, both hormones produce natriuresis either during water diuresis or at low urine flows. When doses of equal antidiuretic activity are injected arginine vasotocin produces greater natriuresis than arginine vasopressin; in this respect, oxypressin is the least potent. The kaliuretic effects of these four peptides are inconsistent. These studies suggest that the 8-arginine of vasopressin is important to natriuretic activity. Substitution of isoleucine for 3-phenylalanine in the ring also increases natriuretic activity relative to antidiuretic activity. This implies that the oxytocin ring also contributes to the saluretic activity of neurohypophysial peptides.
Fluid shifts after hemorrhage
Authors: Baker C. H. , Remington J. W.
Published: December 2017

Fluid shifts were followed in acutely splenectomized dogs by recording changes in hematocrit, plasma specific gravity, total cell volume (Cr51), and plasma volume (T-1824). The dogs were subjected to two serial bleedings, not sufficient in amount to produce any consistent change in pressure, and then a third bleeding to lower the mean pressure to about 60 mm Hg. The first two bleedings produced small declines in plasma gravity in about half the dogs. The hematocrit changed less, which seemed to be evidence for a recruitment of red cells from some unknown locus. This recruitment was verified by total cell volume measurements. When the added cells were taken into account, the tagged cell technique followed the known loss of blood with an average error of but 1%. After the third hemorrhage most dogs showed a plasma gain of ultrafiltrate. Hematocrit and cell volume changes now often depicted a loss of red cells from the circulation. Agreement between expected and measured plasma volumes was not good. A large part of this discrepancy can be ascribed to a steepening of the disappearance slope, a result of the bleeding itself.