bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of cardiac cooling on coronary vascular resistance in normothermic dogs
Authors: Hardin Robert A. , Scott Jerry B. , Haddy Francis J.
Published: December 2017

Coronary vascular resistance was observed while the temperature of the heart was lowered to 25°C. The heart was beating but performing no external work. This was accomplished by shunting the blood around the heart and lungs, clamping the arch of the aorta and perfusing cold or warm blood at a constant rate into the ascending aorta. In most instances, coronary perfusion pressure decreased during perfusion with cold blood. The pressure suddenly fell further as perfusion with warm blood was restarted and then gradually returned to the control level. The heart spent an increased proportion of time in systole during perfusion with cold blood. These findings indicate that local cardiac cooling by the method utilized causes active dilatation of the coronary vascular bed of the dog. This dilatation may result from some direct effect of temperature change upon vascular smooth muscle.
Effect of pericoronary denervation on coronary hemodynamics
Authors: Brachfeld Norman , Monroe R. Grier , Gorlin Richard
Published: December 2017

In a series of 15 dogs, the procedure of pericoronary neurectomy resulted in a relative increase in coronary flow and decrease in oxygen extraction. This was best illustrated by a decrease in coefficient of oxygen extraction (A-V)OO2/AOO2 and was suggested by an increase in coronary flow/oxygen extraction ratio relative to oxygen consumption. It is concluded that at rest the net result of neurogenic impulses (both sympathetic and parasympathetic) is some degree of coronary vasoconstriction. Following denervation, this constrictor tonus is lost and there is a concomitant increase in coronary flow for a given myocardial oxygen consumption.
Altered acceptance and rejection of NaCl in rats with diabetes insipidus
Authors: Titlebaum Libby F. , Falk John L. , Mayer Jean
Published: December 2017

Groups of normal rats and animals with diabetes insipidus were tested on their relative acceptance and rejection of various concentrations of NaCl solution. Rats with diabetes inspidus drank more than normal rats in the hypotonic range. Their acceptance was maximal at a lower solution concentration than in the case of normal animals and relative rejection began at concentrations where normals ingested maximally. The results are discussed in relation to such factors in the internal environment as serum sodium level and extracellular fluid volume.
Sodium and potassium movement in the excised rat aorta
Authors: Dawkins Oswald , Bohr David F.
Published: December 2017

When the rat aorta is excised and placed in a bath of Krebs' solution it loses over two-thirds of its potassium and gains roughly an equivalent amount of sodium within the first 15 seconds. If the aorta is placed in rat plasma instead of Krebs' solution, a similar change occurs. These rapid changes in aorta electrolyte composition do not occur when the whole rat is perfused with Krebs' solution. It is concluded that in the handling involved in the removal of the aorta its cell membrane barriers are altered in such a way that they no longer maintain the normal transmembrane gradients of these cations. After 2 minutes in the bath the potassium in the aorta gradually increases and its sodium decreases suggesting that the cell membrane has regained its characteristics as a barrier and is capable of maintaining sodium and potassium gradients established by an active transport system.
Vascular resistance changes produced by hyperosmotic solutions
Authors: Harvey Rodney B.
Published: December 2017

Isolated dog kidneys were perfused with cold solutions containing electrolytes and colloid. These solutions, when made hyperosmotic by adding mannitol or glucose, produced an increase in perfusate flow. The addition of urea or thiourea to the perfusate had little effect. Epinephrine produced no changes in flow resistance when injected into the renal artery at temperatures below 10°C. The vascular resistance changes produced by mannitol were unaffected by ureteral occlusion and distension of the nephrons. Hyperosmotic mannitol solutions also produced large changes in urine flow and glomerular filtration rate which were opposite to vascular flow changes, suggesting that a large resistance change occurred on the efferent side of the glomerulus. It is suggested that hyperosmotic mannitol and glucose solutions produce a fluid shift across some barrier. This shifting fluid alters flow resistance by lumen restriction. This barrier does not have the characteristics usually ascribed to the glomerular membrane nor is it likely that these changes are due to changes in nephron volume.
Purification and mode of action of a sodium-retaining stimulating factor
Authors: Orti Eduardo , Ralli Elaine P.
Published: December 2017

A method is described for the purification from urine and blood of a substance capable of inducing sodium retention when injected into intact hydrated rats. This procedure includes the following steps: a) dialysis, b) extraction of the nondialyzable fraction with 80–85% ethanol, c) precipitation from the ethanol solution by the addition of ether, d) electrophoresis in polyvinyl blocks of the ether precipitant at pH 4.2, and e) partition chromatography. A bio-assay on intact hydrated rats to determine the presence of the activity was used throughout the purification procedures. The active material was recovered from the urines of hypophysectomized animals and of adrenalectomized animals. The sodium-retaining effect could not be demonstrated in the adrenalectomized animals. The significance of these findings is discussed.
Experimental enlargement of submandibular salivary glands of rats
Authors: Wells Herbert , Munson Paul L.
Published: December 2017

An increase of 12% in fresh and dry weight of the submandibular salivary glands was observed 24 hours after a single amputation of the lower incisor teeth. The effect of repeated amputations was increased by increasing the frequency of amputations and by lengthening the period of amputations. After cessation of a series of amputations, the weight of the hypertrophied salivary glands decreased gradually to approach the control level. Repeated amputation of only one lower incisor tooth was much less effective than amputation of both, and the effect was largely but not entirely restricted to the ipsilateral glands. Ulceration of the adjacent mucosa without amputation of the incisors had no detectable effect on the salivary glands. After amputation of the tips of the incisor teeth without exposure of the pulp or after half-amputations with minimum exposure, the salivary glands increased in weight significantly but much less than after amputation at the gingival margin. It is concluded that the data support the reflex neurological explanation of the phenomenon previously offered by the authors.
Strontium-calcium interrelationships in the mature rat
Authors: Thompson Roy C. , Palmer Ray F.
Published: December 2017

The comparative metabolic behavior of strontium and calcium was studied in mature, female rats exposed both chronically and acutely to Sr90 and Ca45, while on diets of various total calcium contents. When orally administered, there is a discrimination against Sr90 relative to Ca45, apparent in the isotope levels in both blood and bone. This discrimination becomes smaller in magnitude as the level of calcium intake is increased. On all levels of calcium intake there is extensive exchange of calcium and strontium between bone and blood. On low-calcium diets the calcium moving from bone to blood is almost completely reutilized; as the level of dietary calcium is increased, this reutilization becomes less efficient and the rate of net removal of calcium from bone increases. In contrast, the rate of net removal of strontium from bone was relatively insensitive to changes in dietary calcium level, and on all diets was similar to the rate of net removal of calcium on the highest calcium diet.
Cause of hypophosphatemia in hyperthermic dogs
Authors: Kanter G. S.
Published: December 2017

The plasma inorganic phosphate (P) fell from 3.9±0.4 mg % to 1.6±0.3 mg % in eight unanesthetized dogs exposed to an air temperature of 48°C for 2 hours. It was shown previously that this alteration in P was not due to renal excretion. There appeared to be an inorganic-organic P shift in hyperthermia. Dehydration in the absence of hyperthermia and panting did not cause hypophosphatemia. Induction of hyperthermic hypophosphatemia was not inhibited by anesthesia. Hyperthermia was eliminated as the causative agent in three anesthetized, hyperthermic dogs which were curarized and artificially ventilated so as to maintain normal pH. With panting absent, no fall in inorganic P occurred. The effect of the altered pH on phosphate was tested in five anesthetized, curarized, normothermic dogs which were hyperventilated with a respiratory pump. The pH was elevated to an average value of 7.61. In all cases hypophosphatemia occurred. It therefore appears that the increase in pH, due to panting, is the major factor in causing the fall in plasma inorganic P observed in dogs exposed to heat.
Absorption of water, sodium and potassium in small intestine of dogs
Authors: Code Charles F. , Bass Paul , McClary George B. , Newnum Raymond L. , Orvis Alan L.
Published: December 2017

The rates of movement of isotopically labeled water, sodium and potassium from the contents of segments of duodenum and ileum into the blood (insorption) and from blood to the contents (exsorption) were determined in dogs. The insorption of labeled water and sodium from the duodenal and ileal segments was exponential in character. Calculation of insorption and exsorption using the exponential rate and the Visscher formulation gave similar values. Anesthesia produced by pentobarbital sodium had no effect on the insorption of water and sodium from the intestinal segments, but it caused a small decrease in exsorption into the duodenum. Acidification of the contents of the intestinal segments decreased insorption of water, sodium and potassium, whereas it increased the exsorption of sodium and potassium without altering that of water. The results indicate that the mucosa of the duodenum fulfills the function of equilibrating its contents by maintaining nearly equal and large movements of water and sodium in both directions, while that of the ileum is fixed to serve absorption (a net gain to the body) of water and sodium.
Mechanism of the cardiac output reduction by hexamethonium
Authors: Zimmerman B. G. , Brody M. J. , Beck L.
Published: December 2017

The action of ganglionic blocking agents on the cardiac output has been studied in intact, closed-chested animals whose cardiac filling pressure was maintained constant by means of a pressure-stabilizer operating through a jugular catheter introduced into the right heart. Under these conditions cardiodynamic consequences of venous pooling are negated. Hexamethonium produces a fall in cardiac output and blood pressure comparable to that observed in animals without controlled venous pressure. In cardiac sympathectomized animals the cardiac output increases slightly following the administration of hexamethonium. These observations indicate that the ganglion blocking agents reduce cardiac output primarily by blocking tonic sympathetic activity to the heart. The decrease in cardiac output is brought about by a reduction in both stroke volume and heart rate. Sympathetic tone to the blood vessels is reduced by a low dose of hexamethonium before a significant depression in cardiac output occurs.
Unexplained features of the left ventricular pressure pulse
Authors: Remington John W.
Published: December 2017

An accurate record of the left ventricular pressure pulse in the dog is difficult to register, and often cannot be recognized unless a comparison with a simultaneously recorded pulse from the ascending aorta is made. What seem reliable records usually indicate a transient pressure excess over the aortic level when ejection presumably is beginning. Hence, there is a lag of some 5 msec. between the time when the ventricular pressure reaches the aortic diastolic pressure level and the start of the aortic pulse. The timing of the latter is coincident with an inflection on the slope of ventricular pressure rise. The start of the pulse requires little, if any, transmission lag for the first part of the ascending aorta, but does for the descending aorta. The incisura, in contrast, shows a propagation delay from the very mouth of the aorta. The initial steep slope of the aortic pulse, and the height of the inflection, are not necessarily related to the slope of the ventricular pulse, or the excess ventricular pressure height-initiating ejection.
A vasopressor lipid in incubated plasma
Authors: Khairallah Philip A. , Page Irvine H.
Published: December 2017

The presence of a new factor, vasopressor in rats and oxytocic on rats' uteri, has been demonstrated in plasma of dogs, cats, pigs and human beings incubated at 37°C for 24 hours. It is different from the adrenergic amines and the pressor polypeptides and is probably a lysophosphatide produced by an enzymatic reaction in plasma. This enzyme has a broad pH optimum of 8–9, and requires both calcium and phosphate ions for activity. The phosphate ions can be replaced by arsenate, and the enzyme is inhibited by ethylenediaminetetraacetic acid and pyrophosphate. Similar vasopressor and oxytocic effects can be produced by the action of rattlesnake venom on lecithin (animal, impure) dissolved in ether. The plasma factor and the snake venom factor cannot be separated by countercurrent distribution or silicic acid chromatography.
Effect of changes in blood CO2 level on coronary flow and myocardial O2 consumption
Authors: Feinberg H. , Gerola A. , Katz L. N.
Published: December 2017

The effect of hypo- and hypercapnia—induced by changing the respiratory gas mixture—on coronary flow and myocardial oxygen consumption was observed at constant cardiac output and over a broad range of pressure-loads in open-chested, anesthetized dogs. The correlation of cardiac effort (as indexed by the product of heart rate and mean aortic blood pressure) with myocardial oxygen consumption was not altered by increasing or decreasing the arterial CO2 content. Coronary blood flow was observed to be increased relative to the cardiac effort during hypercapnia but not during hypocapnia. The coronary arteriovenous oxygen difference and the percentage of oxygen extracted decreased during hypercapnia pari passu with the increase in venous oxygen content.
Distribution of contractile forces in the iris of cats and dogs
Authors: Apter Julia T.
Published: December 2017

By means of a newly devised technique, the irides of cats and dogs were dissected into segments usually containing only one of the three alleged intraocular muscles. Slits centered in the segments were oriented sometimes radially and sometimes circumferentially. Isometric tensions developed by muscle fibers parallel to the central slits were measured. Graded concentrations of autonomic drugs or graded intensities of electrical current stimulated responses in the sphincter pupillae and in the ciliary muscles. The dose-response curve had an exponential form, reaching an asymptote at maximal response. The strength of the sphincter was markedly greater circumferentially than radially. The ciliary muscles contracted equally and moderately in both directions tested. On the other hand, the ‘dilator pupillae’ never developed tension in either direction to any stimulus. The distribution of contractile forces were, therefore, consistent with the arrangement and density of histologically identifiable muscle fibers, the ‘dilator’ not resembling muscle in either appearance or behavior.
Phase shifting of liver-glycogen rhythm in intact mice
Authors: Halberg Franz , Albrecht Paul G. , Barnum Cyrus P.
Published: December 2017

After the abrupt inversion of a regimen providing for alternating 12 hours of light and darkness the liver-glycogen rhythm of mice feeding ad libitum shifted gradually, rather than suddenly. This progressive shift of liver-glycogen rhythm was slow during the first 4 days after reversal of lighting regimen and faster thereafter. It was completed within 9 days, in intact mature male C mice. Shift-time and shift-rate change are physiologic characteristics of theoretical and applied interest. Phase shifting of rhythms by environmental means proceeds within temporal bounds set by internal phase controls. The interdependence of superficially related periodic functions can be analyzed by phase shifting through study of their shift times.
Radioiodide transport in an iodide-concentrating tumor of thyroid gland
Authors: Wollman Seymour H. , Reed Franklin E.
Published: December 2017

The accumulation of radioiodide in an iodide-concentrating tumor was measured as a function of the time interval after radioiodide injection. From the data, the one-way clearance of serum radioiodide and the fraction of the tumor radioiodide transferred to blood per minute were estimated. The ability of the iodide-concentrating tumor to maintain a radioiodide concentration elevated above that of serum was less than that of normal thyroid. The decrease seems to be related to the low one-way clearance of radioiodide by the tumor as compared with normal thyroid gland.
Secretion of I131 into milk by lactating rat mammary glands
Authors: Grosvenor Clark E.
Published: December 2017

The amount of I131 secreted in 8 hours into milk of lactating rats was determined on the 14th day of lactation using a technique which effected almost complete removal of milk from all 12 mammary glands. The mammary glands and kidneys each trapped 35–40% of the injected I131 dose when the isotope was injected after the mammary glands of the rats had been emptied of milk. The amounts of I131 eliminated via milk and urine were not affected by the dietary level of iodide. Milk from these animals contained twice as much as I131 and four to five times more per gram of milk as milk from glands which were partially full at the time of I131 administration. A significant reduction in thyroidal I131 uptake accompanied the increased loss of I131 via the milk from the previously empty mammary glands. These data indicate that lactating rat mammary glands are powerful iodide traps which, in cooperation with the kidneys, reduce the amount of iodide available for thyroxine synthesis.
High respiratory quotient of dog kidney in vivo
Authors: Cohen Julius J.
Published: December 2017

The R.Q. of the dog kidney was determined in vivo in unilaterally nephrectomized dogs during the infusion of a) NaCl, b) α-keto acids, c) during acute lactate alkalosis and d) during acute acidosis (HCl or H2SO4). The mean (± S.E.) R.Q.'s observed and their statistical significance above unity respectively were a) 1.33 ± 0.07, P < 0.05 ( n = 17); b) 1.27 ± 0.08, P < 0.05 ( n = 19); c) 1.18 ± 0.08, 0.05 < P < 0.10 ( n = 34); and d) 1.14 ± 0.11, P > 0.10 ( n = 32). The excess in renal CO2 production over O2 consumption is interpreted to indicate that a portion of the kidney utilizes substrates by coupled anaerobic oxidation-reductions yielding CO2. The two experimental conditions in which maximal (NaCl infusion) and minimal (acidosis) medullary counter-current multiplier activity should occur were also those with the highest and lowest mean renal CO2 production rates. None of the experimental groups showed any significant changes in O2 consumption. A relationship between renal anaerobic metabolism as manifested by excess CO2 production and renal excretory function is postulated.
Pressure events in bovine esophagus and reticulorumen associated with eructation, deglutition and regurgitation
Authors: Stevens C. E. , Sellers A. F.
Published: December 2017

From 30 experiments on eight adult cows it was found that the peristaltic wave of esophageal contraction associated with the swallowing of saliva traveled down the esophagus at a velocity of approximately 42 cm/sec. During rumination, the marked drop in intrapleural pressure appeared to contribute the primary force for the regurgitation of ingesta into the thoracic esophagus. This aspiratory movement was then followed by an antiperistaltic wave of esophageal contraction which traveled at a velocity of approximately 107 cm/sec. Eructation was accompanied by an esophageal pressure wave of two components. The characteristics of the first component could be explained by the filling of the esophagus with gas driven by the intraruminal/intraesophageal pressure differential and dilation of the pharyngeal esophageal sphincter early in this process. Contributing to the intraruminal/intraesophageal pressure difference were rumen contraction, a small superimposed abdominal press component, and the negative pressure in the thoracic esophagus. The second component of the esophageal pressure wave accompanying eructation was recorded as an antiperistaltic wave of contraction traveling at a mean velocity of 227 cm/sec.
Mechanism of myocardial edema in dogs with chronic congestive heart failure
Authors: Yankopoulos Nicholas A. , Davis James O. , Cotlove Ernest , Trapasso Mary
Published: December 2017

The mechanism of myocardial edema was studied by measuring the changes in the water and electrolyte content of the myocardium of dogs with chronic congestive heart failure and of dogs with other experimental lesions producing chronic ascites. Adrenocortical tissue was also studied for comparison with the changes observed in heart muscle. A marked increase in the water content and in the Na and Cl per gram of fat free tissue solids of the myocardium occurred in congestive heart failure; the K content was unaltered. Assuming that the increment in Cl was distributed extracellularly, this increase in water and electrolytes was extracellular. Chronic passive congestion of the myocardium secondary to elevated right atrial pressure seems to be a major pathogenic factor in myocardial edema formation although hyperaldosteronemia and hypoproteinemia may also play a role.
Ontogenesis of K and Na fluxes in embryonic chick heart
Authors: Klein Richard L.
Published: December 2017

Cation analyses showed that ventricular and atrial K increased gradually during early embryogenesis, reached a plateau by 13 days, and then decreased at hatching. Myocardial Na was extremely high at 2 days, fell markedly by 7 days, and then more gradually through hatching. K influx and efflux in isolated ventricles were relatively high at 7 days, fell at 13 days, and then increased shortly after hatching. Intracellular K exchangeability was relatively constant throughout development at 70%. Na exchange was more complex than K. Intracellular Na exchangeability was only 7% at 7 days, but rose gradually during development to 73% shortly after hatching. The presence of an active transport mechanism in the embryo heart by at least 2 days of incubation was suggested. Enzymatic and electrophysiological correlates were discussed.
Afferent initiation of shivering
Authors: Blatteis Clark M.
Published: December 2017

The activation of shivering was investigated in 30 lightly Nembutalized dogs by surface cooling of the left rear leg amputated at the hip, excepting the bone, the femoral and sciatic-peroneal nerves and the femoral artery and vein. The onset of shivering, although variable, was evidently not dependent on afferent impulses returning from the cooled leg because nerve section before or during cooling did not affect its occurrence; whereas it appeared to be dependent on an effect of the cooled blood entering the truncal circulation because occluding the femoral vessels abolished shivering. There was not any apparent relation of the onset of shivering to deep body, mean skin and/or brain temperatures. The locus of action of the cooled blood in initiating shivering remained undetermined.
Pressure-flow relationships in the coronary vascular bed of the dog
Authors: Scott Jerry B. , Hardin Robert A. , Haddy Francis J
Published: December 2017

The relationship of pressure to flow was studied in the coronary vascular bed of the dog heart. This was accomplished by shunting the blood around the heart and lungs, clamping the arch of the aorta and perfusing arterial blood at known rates into the ascending aorta. Various relationships were observed. Calculated resistance almost always decreased as flow was raised from 25 to 75 ml/min. However resistance decreased, remained constant or increased when flow was increased over the range 75–220 ml/min. An increasing resistance was encountered both in fibrillating hearts and in beating hearts with low initial resistance to flow.
Concentration of renin in kidneys and angiotensinogen in serum of various species
Authors: Schaffenburg Carlos A. , Haas Erwin , Goldblatt Harry
Published: December 2017

In a study of the renin-angiotensinogen interaction, under various conditions of time, temperature and concentration of renin and angiotensinogen, an indirect method for the quantitative determination of renin in the kidneys and of angiotensinogen in the serum of nine species was developed. This method involves the bioassay of the angiotensin formed as a result of the incubation in vitro of purified renal extracts with homologous serum or plasma. Renin and angiotensinogen, at the concentrations of the latter existing in the serum of the various species, were both found to be rate-determining in the process of angiotensin formation. There were striking differences in the concentration of renin in normal kidneys of the various species, with rabbit kidney having more than 70 times as much renin as human kidney. A pronounced increase of renin was found in the ischemic kidney of dogs with experimental renal hypertension. An exceptionally high concentration of angiotensinogen was present in normal human serum compared to that of the eight other species investigated. The results of the previous and present determinations of the renin concentration in the kidneys of various species differ considerably because the former method depended upon a heterologous renin-angiotensinogen reaction, in vivo, while the present evaluation is based on a homologous renin-angiotensinogen reaction in vitro.
Erythrocyte sedimentation rate and blood viscosity as modified by fat emulsions
Authors: Hartwig Quentin L. , Cohn Isidore
Published: December 2017

The effect of lecithin and lecithin-free intravenous fat emulsions on erythrocyte sedimentation and blood viscosity was investigated. Lecithin-emulsified cottonseed oil markedly depressed erythrocyte sedimentation and increased blood viscosity of human and dog blood. This effect was only temporary and the erythrocyte sedimentation rate returned to normal within 24 hours as determined by an in vivo study with dogs. The erythrocyte sedimentation rate of human and dog erythrocytes incubated in cottonseed oil emulsified with polyethylene glycol stearate, more closely resembled that of whole blood. Blood viscosity decreased in the presence of this emulsifier. It is conclude that the influence of lipemia on erythrocyte sedimentation and blood viscosity is due to the emulsifier rather than the oil component of the chylomicron.
Fat deficiency and the calorigenic action of L-thyroxine
Authors: DeMartinis Frederick D. , Paschkis Karl E.
Published: December 2017

The influence of a fat-deficient diet on the calorigenic action of l-thyroxine was investigated. The BMR, endogenous and substrate respiration (succinate) of liver slices and hemidiaphragms were determined. The increase of BMR in fat-deficient animals was confirmed. Furthermore, both endogenous and ‘substrate’ respiration of liver and diaphragm were higher than in controls. When thyroxine was administered, the fat-deficient animals demonstrated a greater BMR response than did controls. Substrate respiration of liver and diaphragm indicated that both fat deficiency and thyroxine treatment increase succinate utilization and that these effects are additive in these tissues.
Freezing point depression of rat kidney slices during water diuresis and antidiuresis
Authors: Bray George A.
Published: December 2017

The freezing point depression of slices of rat kidney removed during water diuresis or antidiuresis has been investigated with a microcryoscopic method. The osmotic pressure gradient in the inner medulla first demonstrated by Wirz has been confirmed. The inner medulla was found to be hypertonic to plasma during water diuresis. Hypotonic tubules were present throughout the cortex and outer stripe of the outer medulla.
Effect of adrenergic blockade with Hydergine on hyperglycemia accompanying hypothermia in dogs
Authors: Kilburn Kaye H.
Published: December 2017

Adrenergic blockade or bilateral adrenalectomy was performed in mongrel dogs to test the hypothesis that the hyperglycemia elicited by immersion hypothermia might be due to epinephrine release. Reduction of body temperature to 27°–30°C raised serum glucose levels from 122 ± 9.8 mg/100 ml standard error (S.E.) to 174 ± 14.8 mg/100 S.E. Whereas treatment with 1.5 mg/kg of Hydergine failed to block hyperglycemia, 4 mg/kg of this drug eliminated hyperglycemia during hypothermia (control 129 ± 4.4 mg/100 ml S.E., hypothermia 120 ± 1.2 mg/100 ml S.E.). Bilateral adrenalectomy less effectively blocked hyperglycemia, and was associated with an intermediate level of serum glucose during hypothermia. Retention of sympathetic tissue outside of the adrenals may have produced the lesser effect of adrenalectomy. It is concluded that hyperglycemia, during immersion hypothermia in dogs, may occur because of intrinsic epinephrine release due to the stress of exposure to cold.
Distribution of some blood constituents in fishes from the Gulf of Mexico
Authors: Sulya L. L. , Box B. E. , Gunter Gordon
Published: December 2017

Several constituents of the plasma of families and species of fishes from Gulf Coast marine waters were studied. Values for sodium, potassium and chloride were found to be higher in elasmobranchs than in teleosts, in agreement with previous work. High salinity teleosts and euryhaline teleosts had a closely similar total electrolyte content, which was somewhat higher than the low salinity teleosts. The value for hemoglobin in several species is recorded for the first time. Highest values were found in the sharks. Cholesterol in primitive species, the sharks and gars, is comparable to the values observed in higher vertebrates but in the higher fishes it is much higher, achieving a level of 1440 gm% in the ten-pounder. The percentage of cholesterol esters is relatively low in the primitive species, but in some of the more highly developed fishes it makes up virtually the entire total cholesterol component. The analogy between the abnormalities observed in nephrotic sera and the apparent normal distribution of plasma proteins and lipids in many species of fishes is discussed.
Effects of acute transitory urinary obstruction in the dog
Authors: Jaenike John R. , Bray George A.
Published: December 2017

A defect in urinary concentrating ability has been produced in the normal hydropenic dog by means of acute ureteral obstruction. This defect is unassociated with changes in urinary solute excretion, and appears to be independent of alterations in glomerular filtration rate. Detailed study of this phenomenon indicates that some functional change in the distal tubular system, related to the ability to concentrate the urine maximally, is produced in the obstructed kidney. The precise nature of this change remains undetermined.
Movement of radioactive tracers across squid axon membrane
Authors: Tasaki I. , Teorell T. , Spyropoulos C. S.
Published: December 2017

Radioactive tracers of potassium, sodium, water, chlorine, sulfate, phosphate and calcium were injected into squid giant axons and the movement of these tracers across the surface membrane was traced either by the standard isotope technique or by the method of gamma-ray spectrometry. The time constants of loss of these tracers through the axon at rest were found to be approximately 8 hours for K42, approximately 3 hours for Na24, 0.7–2 minutes for tritiated water, 25–55 hours for Cl36, 50–85 hours for radioactive sulfate, approximately 50 hours (at the onset) for radioactive phosphate and 20–30 minutes (at the onset) for Ca45. The time constants for the last two tracers were found to increase during experiments, suggesting chemical binding of these tracers with the substance of the membrane and the axoplasm. The effects of repetitive stimulation, potassium depolarization, calcium and magnesium deficiency, etc., upon the movement of the tracers were investigated. Expressed in terms of Krogh's permeability, the ratio of the sodium permeability to the potassium permeability varied under different experimental conditions within the range of 2:1–1:5. The existence of negative fixed charges in the squid axon excitable membrane complex was suggested.
Extralemniscal activation of auditory cortex in cats
Authors: Galambos Robert , Myers Ronald E. , Sheatz Guy C.
Published: December 2017

Unanesthetized cats exhibit a complex pattern of evoked activity at the cortex lasting up to a second or longer following click stimulation to the ear. Transection of the classical auditory pathway at the level of the brachium of the inferior colliculus does not in any significant way alter this pattern of response. Most important, the onset of the response, if affected at all by the section, is delayed only up to 2 or 3 msec. A more medial pathway of prime importance paralleling the classical auditory projection must therefore be postulated. Conduction in this extralemniscal system is completely blocked by deep barbiturate anesthesia while it is left intact by chloralose anesthesia.
Poststimulatory inhibition of galvanic skin reflex in anesthetized cats
Authors: Wang G. H.
Published: December 2017

A galvanic skin reflex is elicited in an anesthetized cat by stimulation of one sensory or mixed nerve and, 10 seconds later, another galvanic skin reflex is elicited by stimulation of a second sensory or mixed nerve with current of the same parameters. The amplitude of the second reflex is reduced just as it is by restimulation of the first nerve at the same interval. This fact indicates that the decrease in amplitude of the second reflex is not due to the fatigue or subnormality of the afferent branch of the arc of the galvanic skin reflex.
Ammonia production in the isolated working rabbit heart
Authors: Feinberg H. , Alma Sister Mary
Published: December 2017

Ammonia production, oxygen consumption, heart rate and blood pressure were observed in the isolated working rabbit heart perfused with Krebs-Ringer solution and with Krebs-Ringer solution containing dog hemoglobin. Oxygen consumption and an index to cardiac effort (heart rate x blood pressure) were shown to be correlated. There was a lesser correlation between ammonia production and cardiac effort. The ratio, ammonia production/oxygen consumption, when both are expressed as micromoles/minute/ gram of heart weight, averaged 0.064 ± .006. Perfusate pH was altered by alternately exposing the perfusate to 95%O2– 5%CO2 and 90%O2–10%CO2. No effect on the ratio ammonia production/oxygen consumption was noted. l-Epinephrine, 0.1–1.0 µg/ml, was continuously infused and resulted in an increase in cardiac effort, oxygen consumption, ammonia production and the ratio of ammonia production/ oxygen consumption.
Effect of ovarian hormones on water and electrolytes in the cow uterus
Authors: Hawk H. W. , Bitman Joel , Cecil Helene C. , Wiltbank J. N. , Bond J. , Sykes J. F.
Published: December 2017

Water and electrolyte characteristics of the uterus varied among groups of estrous, luteal-phase and ovariectomized cows. In the endometrium, estrous cows had highest water content, highest extracellular and lowest intracellular water volumes, and highest Na and lowest K concentrations; ovariectomized cows were at the opposite extreme and luteal-phase cows intermediate for each factor. In myometrium, water content was also highest in estrous cows and lowest in ovariectomized ones. Relative to the other groups, luteal-phase cows had myometrium low in extracellular and high in intracellular water volumes, low in Na and high in K. Ovarian hormones given to ovariectomized cows partially reproduced the characteristics of intact animals.
Metabolic and renal effects of acute hypercalcemia in dogs
Authors: Wallach Stanley , Carter Anne C.
Published: December 2017

The acute metabolic and renal effects of exogenously produced hypercalcemia were studied in hydrated dogs ingesting high- and low-calcium diets, in parathyroidectomized dogs and in dogs receiving vitamin D2. Under all these conditions, elevation of the plasma calcium concentration to 18 mg/100 ml resulted in solute diureses containing all major cations and in hyperphosphatemia. No change in free water clearance or net tubular transport of phosphorus occurred. Further elevation of levels of the plasma calcium caused marked reductions of glomerular filtration, renal plasma flow, and solute excretion and an increase in free water clearance. The increment in cation excretion exceeded the quantity of calcium retained. Less than 50% of the calcium load could be located in the extracellular space and urine at the end of the infusions. Erythrocyte calcium content increased two- to fourfold but erythrocyte concentrations of magnesium and acid-soluble phosphorus did not change. These data suggest that the solute diuresis of hypercalcemia is primarily renal in origin. Displacement of cations from osseous and intracellular sites by calcium may also occur and contribute to the solute diuresis. The hyperphosphatemia is independent of changes in parathyroid function, glomerular filtration and tubular transport of phosphorus and constitutes an unexplained consequence of induced hypercalcemia.
Effect of strophanthidin on the renal tubules of dogs
Authors: Cade J. R. , Shalhoub R. J. , Canessa-Fischer M. , Pitts R. F.
Published: December 2017

The nature and mechanism of the diuresis produced in the dog by strophanthidin was investigated by infusion of the drug into one renal artery. Saline-loaded dogs respond to strophanthidin infusion with a prompt fall in glomerular filtration rate (GFR) and a delayed saluresis and diuresis. The effect on electrolyte transport can be blocked by loading with potassium salts but the fall in GFR can be only partially prevented. Strophanthidin given to adrenalectomized dogs produces the same effect as in the intact animal. The ability to maintain a steep transtubular hydrogen ion concentration gradient is severely impaired. The data are best interpreted as inhibition of the potassium arm of a linked Na-K exchange across the peritubular cell membrane, with diuresis occurring secondary to this block. Impairment of the ability to maintain a steep hydrogen ion concentration gradient indicates an additional effect on linked exchange occurring at the luminal surface of the cell.
Renal activity of vasopressin in anesthetized dogs
Authors: Perlmutt Joseph H.
Published: December 2017

Conventional clearance techniques were used to study the renal response to vasopressin (5–100 mu/hr.) infused for 2 1/2 hours into anesthetized (pentobarbital), surgically traumatized dogs elaborating a dilute urine. Decreased urine flow, a concomitant sustained increase in Na+ excretion, increased urine osmolality, negative free-water clearance and an increased osmolal U/P ratio (>1, <2) consistently occurred during the infusion of 50 mu/hr. Urinary pH rose and HCO3–, rather than Cl–, was the predominant anion excreted. Tubular rejection of HCO3–, however, is not essential for vasopressin activity under the conditions of this investigation since antidiuresis occurred in an acidotic dog. Usually some increase in glomerular filtration rate and effective renal plasma flow were apparent during vasopressin infusion; the former change could account for the increased Na+ excretion, but it is difficult to ascribe the peculiar anion behavior to this factor. Maximum urinary concentration was not attained even with 100 mu vasopressin/hr.
Ammonia toxicity and cerebral oxidative metabolism
Authors: McKhann Guy M. , Tower Donald B.
Published: December 2017

Effects of NH4Cl on oxidative metabolism of cat cerebral cortex slices and mitochondria incubated in vitro were studied. In slices, addition of 10 mm NH4Cl to the incubation medium resulted in significant (16%) reduction of O2 uptake, doubling of lactic acid production and marked increase of glucose utilization compared to control slices. Mitochondria showed a 30–40% decrease of O2 consumption in the presence of 15 mm NH4Cl when pyruvate or α-ketoglutarate were substrates, but little if any difference from controls with succinate, glutamic acid or γ-aminobutyric acid as substrates. Pyruvate utilization by ammonia-treated mitochondria was inhibited to the same degree as O2 consumption and was not increased by supplementing the incubation medium with excess succinate. Additions of α-lipoic acid, thiamine pyrophosphate or DPN to such preparations failed to reverse the NH4Cl effect. Satisfactory P/O ratios were obtained for all mitochondrial preparations. It is concluded that a primary toxic effect of ammonia on the brain may be direct interference with oxidative decarboxylation of pyruvic and α-ketoglutaric acids.
Metabolic changes of excitable tissues in sodium-free hydrazinium solution
Authors: Abood L. G. , Koketsu K. , Barbato L. , Dobbs B.
Published: December 2017

Phosphorylation was measured by means of P32 in various excitable tissues immersed in sodium-free hydrazinium solution. Despite the fact that phosphorylation was inhibited as much as 80%, the electrical properties were essentially unchanged. In hydrazine solution, the PCr content decreased over 50% while ATP and other nucleotides showed relatively little change, suggesting that the bioelectric potentials are not related to PCr content. Hydrazine (Hz) was found to be a potent inhibitor of oxidative phosphorylation of rat brain mitochondria at concentrations comparable to the intracellular concentration needed for excitability. Hz was found to greatly stimulate the enzymatic reaction pyruvate + DPNH → lactate + DPN. The reverse reaction was increased as much as fivefold by Hz. The conclusion was reached that excitability of frog spinal ganglia and other excitable tissues was not dependent on active metabolism, even after many hours in Hz solution.
Respiration of liver slices from normal and altitude-acclimatized rats
Authors: Frehn John L. , Anthony Adam
Published: December 2017

Analyses were made of the respiratory rates of liver tissue slices from normal rats and from rats continuously exposed to simulated altitudes of 21,000 ft. for periods varying from 1 to 56 days. Seventy-one rats were used. Oxygen uptake was measured in 100%, 20% and 1% oxygen. There was no difference in tissue respiration between the control and experimental animals, either with no added substrate or with glucose or succinate as added substrates. It was concluded from these data that alterations in cellular respiration do not constitute an important feature of altitude acclimatization.
Mercaptide conjugation in the uptake and secretion of sulfobromophthalein
Authors: Philp J. R. , Grodsky G. M. , Carbone J. V.
Published: December 2017

Sulfobromophthalein (BSP) was injected into rats, and the livers were excised at timed intervals. The ratio of free to mercaptide-conjugated BSP in the liver was determined after extraction and chromatographic separation. After 2 minutes, 12.5% of the total dose was concentrated in the liver; of this, 65% was free BSP. At 5 minutes, 33% of the total dose appeared in the liver, of which approximately 50% was still in the free form. Increasing concentrations of BSP were infused or administered as a single injection, and free and conjugated pigment appearing in the bile was measured. The maximum secretion rate for free BSP was 3–7 µg/ min/gm liver. Maximum capacity for secretion of conjugates was not reached, even when 60 mg BSP/kg body weight was administered. When purified metabolites were injected, they were rapidly secreted into the bile. It was concluded that uptake of BSP from the blood is a dynamic process which precedes and is relatively independent of the conjugation step. In contrast, conjugation may be the rate-limiting step in determining the secretion rate of the pigment from the hepatic cell.
Water and sodium exchange in renal tubule fluid
Authors: White H. L. , Rolf D. , Tosteson D. C.
Published: December 2017

The entry and exit of water into and out of the renal tubular fluid of dogs was measured by infusing tritium-labeled water (THO) into the renal artery either during (entry) or before (exit) a period of stopped urine flow. The results show that THO moves more slowly between urine lying in the most distal nephron segments (presumably collecting ducts) than between urine lying in more proximal segments and blood plasma. From the reduced rate of labeling of renal medullary, as compared with cortical, tissue with THO and Na22 infused during stopped urine flow, it is concluded that the slow exchange of collecting duct with plasma water is partly due to a slow rate of labeling of the renal medullary extratubular water and Na by the blood stream. From the failure of collecting duct water and Na to come into isotopic equilibrium with medullary water and Na either during a 5-minute period of stopped urine flow or during the subsequent collection of a few stop-flow urine samples, it is concluded that the collecting duct wall offers significant resistance to diffusion of THO and Na22 and thus also contributes to the slow exchange of these substances between plasma and collecting fluid. The bearing of these results on present theories about the way in which the kidney handles water and Na is discussed.
Reflex stimulation of heart induced by partial occlusion of pulmonary artery
Authors: Taquini Alberto C. , Aviado Domingo M.
Published: December 2017

In anesthetized dogs, partial occlusion of the pulmonary artery causes increased pulmonary blood flow which is dependent on an intact sympathetic innervation of the heart. Neither the vagi nor the medullary centers participate in the increase in pulmonary blood flow. The most probable explanation is that the increase in pulmonary blood flow is due to reflex cardiac stimulation initiated by a rise in right ventricular systolic pressure and mediated entirely by the cardiac sympathetic nerves.
Electrolytes and osmotic balance of muscle in solutions of nonelectrolytes
Authors: Bozler Emil
Published: December 2017

In Ringer's solution to which urea or glycerol was added the stomach muscle and sartorius of the frog lost K and Na and a corresponding amount of water. Under the same conditions sucrose produced a greater loss of water, but had no effect on cations. In isosmotic solutions of erythritol stomach muscle swelled more than in sucrose solutions, but swelling could be prevented by adding 1 mm CaCl2/l. In such solutions the fibers lost about half of their cations. Osmotically this loss was approximately balanced by the amount of erythritol which entered. In solutions of sucrose the fibers lost less K and Na and took up a correspondingly smaller amount of the nonelectrolytes.
Vasodilation in skeletal muscle during activation of patellar reflex
Authors: Sonnenschein R. R.
Published: December 2017

The muscular hyperemia accompanying the patellar reflex was studied in decerebrate cats with and without sympathetic block, and compared with the vascular response resulting from equivalent muscle activation through stimulation of the intact or centrally blocked motor nerve. No obvious differences were seen in the vascular responses under these conditions, except possibly in the latency and pattern of onset of the response. It is concluded that, with the possible exception of the latter feature, the vasodilation accompanying the patellar reflex is independent of the central nervous system.