bluuebunny/crossref_metadata_2025 huggingface dataset:
Localization of the Site of Action of Mercurial Diuretics by Stop Flow Analysis
Authors: Vander Arthur J. , Malvin Richard L. , Wilde Walter S. , Sullivan Lawrence P.
Published: December 2017

Experiments utilizing the new technique of ‘stop flow’ analysis have been performed to localize the renal site of action of mercurial diuretics. Control ureteral occlusions were done on dogs after stabilization of mannitol osmotic diuresis. After release of occlusion and collection of samples, either thiomerin or meralluride (4–8 mg Hg/kg) was administered and a second occlusion performed forty minutes later. The mercurials caused at least a 50% reduction in the mass of water and sodium reabsorbed by the proximal tubule during the brief period of occlusion. These reductions were equivalent so that the sodium concentration of the proximal reabsorbate always remained plasma-like. The mercurials did not interfere with the ability of the distal tubule to lower urinary sodium concentration during the period of ureteral occlusion.
Analysis of Vagal and Cholinesterase Effects on the Heart of Chelydra serpentina
Authors: Yonce Lloyd R. , Brassfield Charles R.
Published: December 2017

Cholinesterase, applied to the isolated turtle heart, caused a decreased inotropic and chronotropic inhibition when the vagus nerve was stimulated with multiple shocks, but caused an increased inotropic inhibition when the vagus was stimulated with a single shock. The beating of the atrium is an active force in modifying the effect of endogenous acetylcholine on inotropic inhibition. This is indicated by: a) cholinesterase will not decrease the amount of inhibition caused by a single shock; b) when different ambient solutions are used, the amount of inhibition from a single shock to the vagus varies, but the number of beats required to obtain the lowest amplitude of contraction remains the same; c) at the end of a multiple stimulation which causes complete chronotropic inhibition, the atrium must still pass through the phase of decreasing amplitude before recovering; d) during cholinesterase, the inotropic and chronotropic inhibition during multiple stimulation allowed the recovery to start at a higher rate than before cholinesterase. Velocity constants were obtained from the recovery curves before, during and after cholinesterase. Computed curves based on the velocity constants and a geometric progression closely approximate the experimental data showing temporal summation of inotropic inhibition from submaximal stimulation of the vagus nerve before and during cholinesterase application.
Relation Between Body Fat and Glycogen Levels of Inbred Strains of Mice
Authors: Lyon John B.
Published: December 2017

Previous studies suggested that an inverse relation existed between concentrations of body fat and muscle glycogen among inbred strains of mice. Of six strains, one, the I strain, was resistant to obesity, and the levels of muscle glycogen were 3–6 times greater than those of the other five strains. Because the tentative proposal was based on data from only one lean strain, mice of the DBA strain were studied as another possible lean strain. Although small animals, sublines 1 and 2 of this strain became obese when fed a 50% fat diet, and the levels of muscle glycogen were in the range of the other five obese strains. It was also found that concentrations of body fat up to 25% could be induced in 4–5-month-old mice of the I strain, and by dietary means alone. The concentrations of muscle glucogen in these mice were not lower than those of I strain mice exhibiting concentrations of body fat of 11%. It was concluded, therefore, that an inverse relation between carbohydrate and fat stores does not exist among inbred strains of mice. The unusually high levels of muscle glycogen in the I strain appear to be unique, and are most likely genetically determined.
Factors Influencing Movement of Calcium in Vertebrate Striated Muscle
Authors: Cosmos Ethel
Published: December 2017

Stimulation of isolated frog muscles at a frequency of one shock per second increases at first the rate of exchange of Ca40 with Ca45 but after 3 hours the total exchange is the same as in the unstimulated control muscles, only about 44% of the calcium being radioactive. Subsequent stimulation of the control muscles does not increase the specific activity. When Ca45 is injected i.p. in frogs the muscles exchange 26% of their Ca in 30 minutes and this level is not further increased for 8 hours. When the frog is stimulated at 15 shocks/min. the exchange becomes 100% in 400 minutes. With higher frequency of stimulation the complete exchange is achieved more rapidly. Repeated daily injection of Ca over a period of 6 days results in 80% exchange without stimulation. Stimulation of one leg only results in greater exchange in the stimulated leg. If the Achilles tendon is cut on one side and both sides are stimulated the exchange is more rapid on the operated side. Young rats injected with Ca45 exchange all their muscle Ca in 100 minutes without artificial stimulation.
Effects of Abrupt Temperature Changes on Excretion Characteristics of Rats Acclimated to Cold, Neutral or Hot Environments
Authors: Mefferd Roy B. , Hale Henry B.
Published: December 2017

The responses of acclimated rats (heat, 35°C; neutral, 24°C; or cold, 3°C) to abrupt temperature changes (24-hr. exposure with fasting) are compared. Variables studied include weight loss, rate of fasting weight loss regain, water intake, urine volume, urinary Na, K, Ca, Mg, PO4, urea, uric acid, creatinine, creatine, taurine, ß-alanine, glycine, α-alanine, valine + methionine, serine, threonine, tyrosine, glutamic acid, aspartic acid, lysine, arginine and histidine. As compared to the neutral controls, most of the variables of the heat- and cold-acclimated rats were different under all conditions tested. Despite adaptive changes induced by the prior treatments, however, the changes directly attributable to abrupt environmental shifts were somewhat similar for the majority of the variables to those of the controls. Other variables in the cold-acclimated group tended toward nonresponsiveness, while the the heat-acclimated group tended toward overresponsiveness. Return to the neutral environment did not always result in a normalization, though the tendency was often in this direction.
Effect of Bone Marrow-Spleen Injection After Fast Neutron Irradiation in Mice
Authors: Cole Leonard J. , Ellis Marie E.
Published: December 2017

Page 17: Leonard J. Cole and Marie E. Ellis, "Effect of Bone Marrow-Spleen Injection After Fast Neutron Irradiation in Mice." Corrected table 1.

(See PDF for Table)
Mechanisms of Respiratory Inhibition Produced by Sudden Aortic Obstruction
Authors: Gilfoil Thomas M. , Schopp Robert T. , Norris Gail R. , Youmans W. B.
Published: December 2017

Page 158: Thomas M. Gilfoil, Robert T. Schopp, Gail R. Norris and W. B. Youmans, "Mechanisms of Respiratory Inhibition Produced by Sudden Aortic Obstruction." Legend for figure 5 should read: Breathing virtually uninfluenced by sudden sharp rise in arterial pressure following internal occlusion of the descending aorta in animal with sino-aortic mechanism eliminated (tracings same as in fig. 1).
Diminution of insulin effect by growth hormone in hypophysectomized dogs; studies with C14 glucose
Authors: Altszuler N. , Steele R. , Dunn A. , Wall J. S. , de Bodo R. C.
Published: December 2017

The mechanism whereby growth hormone diminishes the hypoglycemic effect of insulin was investigated in hypophysectomized dogs using a C14 glucose dilution technique. An intravenous injection of insulin into the normal dog increased the rate of glucose utilization, and the resulting hypoglycemia was promptly abolished by an increased rate of glucose production. In the hypophysectomized dog prior to growth hormone administration, the insulin injection increased the rate of glucose utilization to a greater extent than in the normal animal, while the ability to increase the rate of glucose production was shown to be limited. In the hypophysectomized dog, a growth hormone regimen (1 mg/kg/day for 4 days) increased the rate of glucose production and utilization. The intravenous injection of insulin during the growth hormone regimen resulted in a lesser increase in the rate of plasma glucose utilization than observed prior to the growth hormone regimen. Furthermore, the growth hormone regimen improved the animal's limited ability to increase glucose production in response to the insulin-induced hypoglycemia. These effects of growth hormone contribute to the decreased effectiveness of insulin. The relationship of the ‘anti-insulin’ effect of growth hormone to its influence on glucose turnover is discussed.
Localization of magnesium-28 in the myocardium
Authors: Glaser W. , Brandt J. L.
Published: December 2017

The finding of an unusual concentrating ability of cardiac muscle for magnesium-28 compared to skeletal muscle was confirmed. An extension of this observation showed that the interventricular septum had an even greater ability to concentrate magnesium-28 as compared to the left and right ventricular walls. Studies of isolated Purkinje system in two calves made it unlikely that the distribution of this specialized tissue was the explanation for the distribution of magnesium-28 in the different portions of the ventricles.
Mechanics of pulmonary circulation in isolated rabbit lungs
Authors: Engelberg Joseph , DuBois Arthur B.
Published: December 2017

A new method has been devised for measuring the compliance (volume change ÷ pressure change) of the pulmonary arterial tree (down to the capillaries), in isolated, Krebs-Ringer-perfused rabbit lungs. The lungs were suspended in a plethysmograph and inflated with N2O. Fluid was introduced into the pulmonary artery by a motor driven syringe and the volume injected was recorded. The capillary flow was deduced from the plethysmograph pressure change which resulted from N2O uptake. Vascular volume change equaled arterial inflow minus outflow into capillaries. The compliance of the venous tree was similarly measured by retrograde perfusion. Mean compliance of the pulmonary arterial tree was 0.17 (S.E. 0.02) ml/cm H2O in six rabbits, mean weight, 4.4 kg. Mean compliance of the pulmonary venous tree was 0.41 (S.E. 0.03) ml/cm H2O in five rabbits, mean weight, 4.3 kg. Compliance of the whole bed (not including the left atrium) was 0.69 (S.E. 0.06) ml/ cm H2O in six rabbits, mean weight, 4.4 kg. Equations were derived relating the length, diameter and number of vessels in the vascular bed. From these the inertance of the blood in the pulmonary arterial tree was estimated to be 8 gm cm–4 in rabbit lungs and 1 gm cm–4 in human lungs. The flow response to sinusoidal pressure waves of different frequencies was calculated, assuming a system with lumped compliance, inertance and resistance. The input impedance of the pulmonary vascular bed, in the rabbit and in man, was minimum for a frequency midway between the fundamental frequency and the second harmonic of the resting heart rate.
Changes in blood of dogs and rabbits by high fat intake
Authors: Swank Roy L.
Published: December 2017

The effect of large butter-fat meals on the blood of rabbits and dogs has been studied. Marked distortion of the red blood cells with adhesiveness and aggregation was observed. This was accompanied by slowing of the circulation and by changes in the surface tension of the plasma. In addition changes in the platelet counts, white blood counts, hematocrit and erythrocyte sedimentation rates were observed. Changes were also noted in the buffy coat, in the clotting time and in the nature of the clot.
Changes in composition of the urine in ureter and bladder at low urine flow
Authors: Levinsky Norman G. , Berliner Robert W.
Published: December 2017

The movements of water and solutes across the ureter and bladder have been studied under conditions approximating those routinely used in physiological experiments at low urine flows. When the ureter and bladder are perfused at flows of less than 1 ml/ min. movements of water, urea, sodium, potassium, chloride, creatinine and hydrogen ion occur. The magnitude of these changes increases as the rate of perfusion is decreased or when urine is allowed to pool in the bladder. All movements of water and solute are in the direction of their concentration gradients. The movements are not affected by changes in antidiuretic activity, anaesthesia or surgical manipulation. Fluid collected from an indwelling Foley catheter draining continuously at a rate of 0.1 ml/min. may have an osmolality approximately 10% lower than that of the fluid entering the ureter and a urea concentration about 15% lower. When urine is allowed to accumulate in the bladder during 30-minute periods at the same flows, the changes may be 50–100% greater. At low urine flows, the composition of urine collected from the bladder does not accurately represent the composition of the urine as it leaves the kidney.
In vitro and in vivo adrenal corticosteroid secretion following stress
Authors: Knigge Karl M. , Penrod Chloe H. , Schindler William J.
Published: December 2017

Sprague-Dawley rats were ssressed by scalding or by physical immobilization. Several aspects of the pituitary-adrenal response after these stresses were examined by: a) in vivo adrenal vein cannulation with chromatographic identification and estimation of the rate of secretion of corticosterone; b) measurement of the in vitro steroidogenesis by adrenal gland slices; c) determination of adrenal ascorbic acid concentration, and d) determination of the pituitary ACTH content. After the stresses of either scalding or physical immobilization, there was an initial biphasic response consisting of a brief elevated secretion of hormone followed by a period of lower or less than normal output. After this initial response, the expected high, sustained rate of hormone secretion was observed. The low level of hormone secretion during this initial biphasic response was not due to secretory exhaustion of the adrenal, and the pituitary contained approximately a twice-normal concentration of ACTH. The low level of hormone secretion was replaced by very high levels by treatment of the stressed rat with reserpine or by placement of hypothalamic lesions. At a variable time after stress, corresponding to time of least corticosteroid secretion, there appears to exist an inability of the pituitary to release ACTH, which may be due to cessation of the initial hypothalamic stimulation or to a neural mechanism which temporarily suppresses or inhibits the secretion of endogenous ACTH.
Role of the adrenal in ethionine mobilization of fat
Authors: Brownell Katharine A. , Hartman Frank A.
Published: December 2017

We have shown that ethionine increases the liver lipid in normal fasted mice but this effect is not accentuated by epinephrine. Likewise ethionine increases lipid in the liver of fasted mice with demedullated adrenals while epinephrine produces no significant increase. In the adrenalectomized mouse epinephrine did augment deposition of lipid in the liver when combined with an amount of cortisone too small to be effective per se. A somewhat larger dose of cortisone was just as effective as these two substances combined. Still greater amounts failed to increase the effect. A dose of adrenal extract sufficient to maintain normal behavior and a satisfactory weight gain, proved inadequate for the normal response to ethionine probably due to the absence of an essential hormone. However it was as effective as any dose of cortisone.
Cause of hypoglycemia in dogs exposed to heat
Authors: Kanter G. S.
Published: December 2017

When unanesthetized dogs are exposed to heat (120°F) for 4 hr. with no water available for drinking, hypoglycemia results. One would expect that the dehydration, which also occurs, should physically cause an increase in blood glucose concentration as is usually found in man. The tendency is present in dogs but the utilization of glucose is sufficiently rapid to offset the hemoconcentration and cause a fall in glucose levels even when exogenous glucose is given at the rate of 1% body wt/hr. of 11% glucose by stomach tube. This increased utilization has been demonstrated to be mainly due to involvement of the respiratory muscles which are used in the panting mechanism for no fall in blood glucose occurs under similar conditions when the animal is curarized. The evidence indicates that the hypoglycemic mechanism present in dogs is not a species phenomenon but is probably also present in man under appropriate conditions. In both man and the dog whether hypoglycemia occurs will depend upon the degree of involvement of the respiratory apparatus.
Stimulus factors in septal self-stimulation
Authors: Ward Henry P.
Published: December 2017

The parameters of electrical stimuli effective in producing sustained self-stimulation behavior were studied in the septal region in rats. Constant current sine wave stimuli were effective over a wide, but specific, range of frequencies, 40–1000 cps, suggesting that the proper choice of stimuli might separate effects essential to the self-stimulation phenomenon from any concomitant but unrelated effects having different frequency sensitive characteristics. The interrelation of current, pulse duration, and frequency using a modified rectangular wave form at low frequencies was explored by threshold measurements. The quantity of electricity delivered for each bar press was more important than either the frequency or pulse current per se, but this in turn depended on the pulse duration used. The longer the pulse duration the more coulombs were required to achieve threshold. Single pulses were ineffective in producing sustained self-stimulation.
Relation between spinal level and peripheral location of afferents in calf muscles of the cat
Authors: Swett John E. , Eldred Earl
Published: December 2017

The relationship between the location of sensory endings in the medial gastrocnemius or soleus muscles of the cat and the level of entrance into the cord of their afferents has been studied. The hind legs were denervated except for the medial gastrocnemius or soleus muscle and the lumbosacral cord bathed in an oil pool. Afferent rootlets in the dorsal roots of L7 and S1 were examined in cranio-caudal sequence in search of filaments coming from the muscle under study. Indirect stimulation of the muscle permitted identification of the afferent as a muscle spindle or tendon organ, and distinction between annulospiral and flower-spray afferents was made on the basis of conduction rates. The position of the afferent ending in the muscle was found by probing the surface lightly with a blunt instrument. Results indicate that: a) since only one sensitive focus in the muscle is detectable for an isolated dorsal root filament, only one spindle or Golgi organ is innervated by an afferent fiber; b) the regions of inflow of annulospiral, flower-spray and Golgi afferents coincide; c) the relation between position of the afferent within the muscle and exact level of entrance in the cord is largely a random one.
Relationships between contraction and membrane electrical activity in the isolated uterus of the pregnant rat
Authors: Landa Jorge F. , West Theodore C. , Thiersch John B.
Published: December 2017

Isolated uterine segments from 21-day pregnant rats of the Long-Evans strain were studied by the microelectrode technique in conjunction with force of contraction measurements. Dual recording from large segments showed gross discoordination in onset, frequency and duration of action potential trains. Dual recording from small (2 mm in width) segments resulted in coordination of onset, frequency and duration of spike discharge, but subtle phase shifts between recordings from closely adjacent electrodes still were evident. In the small segments, each action potential accounted for a separate deflection on the contraction curve, indicating the tetanic nature of the uterine contraction. A ‘precontraction’ was regularly observed in the small segments, preceding both fast contraction and the appearance of the spike discharge. Possible mechanisms to explain the nature of impulse conduction are discussed.
Effect of Diamox on plasma and urine acid-base composition during chronic respiratory acidosis
Authors: Carter Norman W. , Seldin Donald W. , Teng H. C.
Published: December 2017

Diamox, administered during experimental chronic respiratory acidosis in an amount sufficient to inhibit completely renal carbonic anhydrase, resulted in marked increase in plasma pCO2 and bicarbonate concentration. Inhibition of red blood cell carbonic anhydrase was probably responsible for the very high plasma pCO2 observed. The high pCO2, in turn, was capable of so accelerating the uncatalyzed formation of carbonic acid in the renal tubular cell that sufficient secretion of hydrogen ion occurred to accomplish reabsorption of even increased amounts of filtered bicarbonate in the face of complete inhibition of renal carbonic anhydrase. Despite accelerated bicarbonate reabsorption, hyperchloremia and potassium deficiency supervened in blood, ammonia excretion increased, and renal glutaminase was activated.
Oxygen transport in hemorrhagic shock as a function of the hematocrit ratio
Authors: Crowell Jack W. , Ford Robert G. , Lewis Virginia M.
Published: December 2017

The oxygen consumption, arterial and venous oxygen concentration, and the arterial blood pH were measured, and the cardiac output, peripheral resistance and maximum oxygen transport capacity determined in 75 dogs with different hematocrit ratios in which the blood pressure had been maintained at 30 mm Hg for 15 minutes. The O2 consumption increased as the hematocrit ratio increased until the hematocrit ratio reached 42. However, an increase in the hematocrit ratio above 42 caused a decrease in O2 consumption. This optimal hematocrit ratio occurs because of the dual role of the hematocrit ratio in determining O2 content of blood and blood viscosity. A curve obtained by multiplying cardiac output times arterial O2 showed that when the hematocrit ratio is 42 the O2 transport is maximal. The oxygen consumed by the animal was determined by the oxygen available. Arterial blood pH was highest in those dogs with the greatest oxygen consumption, but the pH was below limits compatible with life in the anemic animals. Total peripheral resistance increased greatly as the hematocrit ratio increased. Analysis of the data showed that the rate of maximum resistance to hemorrhagic shock coincides with the hematocrit ratio range of maximum O2 transport. Also, the rate of development of an oxygen debt determines how long the animals can remain hypotensive without developing irreversible shock and indicates that, regardless of the hematocrit ratio, a fixed oxygen deficit must occur before irreversible shock develops.
Effect of time and volume of blood overtransfused on the loss of plasma and protein in the dog
Authors: Smith E. L. , Deavers S. , Huggins R. A. , Stolzoff G.
Published: December 2017

The effects of the duration of a transfusion and the volume of blood transfused on the loss of plasma volume and protein was investigated in the dog. Plasma volume was measured with radioactive I131-tagged albumin and plasma protein by the falling drop method. When dogs are transfused above their initial blood volume with 10 cc/kg of blood in a mean of 10 minutes there is no significant loss of plasma volume or protein, whereas if the same volume is given in 20 minutes there is a significant loss of both. An initial transfusion of 20 cc/kg would appear to be a physiologic transition point for the loss of plasma volume and protein compared to initial transfusions of 10, 30, 40 or 50 cc/kg.
Responses at cerebral somatosensory I and peripheral nerve evoked by graded electrocutaneous stimulation
Authors: Rosner Burton S. , Schmid Ethel , Novak Stanley , Allison J. Truett
Published: December 2017

Evoked potentials were recorded with macroelectrodes from peripheral nerve and cerebral somatosensory I of anesthetized cats following graded electrocutaneous stimulation. The sizes of the peripheral and cortical responses increased according to multiple-limbed functions as stimulus intensity grew. Each negatively accelerated limb of the cortical function began and reached asymptote at the same intensities as did the companion limb of the nerve function. The cortical response grew less rapidly than the response of nerve at high intensities and more rapidly at low intensities. Within each limb of the nerve function, however, the cortical response linearly followed the nerve response. Cortical potentials evoked by stimulation of a fixed cutaneous locus displayed lower thresholds and higher amplitudes in the central region than out towards the perimeter of the cortical representation of that locus. The high-threshold responses did not reverse polarity upon intracortical recording, did not potentiate upon application of strychnine or Metrazol, and disappeared following ablation of the central part of the representation which yielded potentiated responses upon strychninization. The high-threshold responses thus seem due to volume conduction.
Effects of temperature on function of mammalian (rat) muscle
Authors: Doudoumopoulos Alexander N. , Chatfield Paul O.
Published: December 2017

Results are reported on the effects of local cooling on the function of a mammalian muscle (rat gastrocnemius) stimulated with supramaximal shocks both through its nerve and directly after complete curarization of the animal. By varying the two parameters of muscle temperature and stimulus frequency, complex, though reproducible, curves relating the amount of tension developed as a function of temperature at any given stimulus frequency were obtained. In general, the muscle developed more tension when cooled between certain temperature limits and when stimulated between certain frequency limits. The results were the same on both indirect and direct stimulation, indicating that the effects of temperature at the neuromuscular junction were not the critical elements in the phenomena observed. These rather unexpected observations suggest that perhaps in such diseases as myasthenia gravis it might be profitable to reexamine the role of the neuromuscular junction as contrasted with a possible primary disorder of the contractile mechanism.
Protective effect of artificially induced ‘hibernation’ against lethal doses of whole body x-irradiation in CF1 male mice
Authors: Kuskin Sondra M. , Wang S. C. , Rugh Roberts
Published: December 2017

Hypothermia induced by the use of neuroplegic drugs such as Hydergine, chlorpromazine or promethazine, followed by refrigeration, does not significantly enhance the protective action afforded by refrigeration alone against the lethal dose of whole body x-irradiation in CF1 male mice. The neuroplegic drugs, without refrigeration, provide a slight degree of protection, probably due to the slight reduction in the body temperature. It appears that the action of hypothermia as a protective mechanism depends not on depression of metabolism alone, but on a general depression of bodily processes. Urethane, in conjunction with refrigeration, appears to augment the lethal effect of x-irradiation in the CF1 strain of male mice.
Relationship between potassium, acid secretion and bioelectric potentials of frog gastric mucosa in the presence of histamine and thiocyanate
Authors: Harris John B. , Edelman Isidore S.
Published: December 2017

The transmucosal potential difference (PD), the rate of H+ secretion and the net flux of potassium from nutrient to secretory phases (JnsK) of the frog gastric mucosa were studied in vitro by the chamber method. Histamine produced a fall in PD, a sustained increase in H+ production and an equivocal rise in JnsK. Increasing the nutrient potassium concentration (Kn) to 8.5 mEq/l. in the presence of histamine induced a depression in PD, although the rate of acid secretion was unchanged. Hydrogen ion secretion decreased when the nutrient potassium concentration was decreased to 1 mEq/l. despite the continued presence of histamine. The response of JnsK to alterations in nutrient potassium concentration was unaffected by the presence of either histamine or thiocyanate. Thiocyanate produced almost complete inhibition of H+ secretion and a rise in PD. Raising the nutrient potassium concentration in the presence of thiocyanate produced a prompt and sustained fall in PD, followed by a transient rise when Kn was lowered. Alterations of the nutrient potassium concentration in the presence of thiocyanate had no effect on the rate of acidification. The data indicate that under certain circumstances PD and H+ secretion can be uncoupled and that the inverse relationship between Kn and PD is substantially independent of the rate of H+ secretion.
Pressure-flow relationships in the isolated perfused rabbit heart
Authors: Day Stacey B. , Johnson John A.
Published: December 2017

The present study was undertaken to investigate the relationship between pressure and flow in the isolated mammalian Ringer's fluid-perfused rabbit heart. Results indicate that in the isolated euthermic rabbit heart the pressure-flow relationship, including observations for very low ranges of pressure and flow, is curvilinear with the curve convex to the pressure axis and tending to pass through the origin. These studies have presented no evidence for a generalized critical closing pressure in the isolated heart at normal temperature.
Apparent sodium space of the dog
Authors: Neely William A.
Published: December 2017

After the intravenous injection of 2 gm/kg of sodium chloride in 20% solution in dogs whose total urine output was reinfused intravenously, sodium spaces were found to be 80 ± 2.8% of total body weight. The chloride space was found to be 58 ± 1.6% of the total body weight. Urine flow increased markedly. Plasma potassium concentration fell. The large sodium space was thought to be due to large total body water spaces in our animals or to the presence of a nonaqueous sodium space.
Localization of action of chlorothiazide in the nephron of the dog
Authors: Kessler Richard H. , Hierholzer Klaus , Gurd Ruth S. , Pitts Robert F.
Published: December 2017

Localization of the actions of chlorothiazide in dogs has been studied by the ‘stop-flow’ technique. The compound interfered with the reabsorption within the proximal segment of a portion of the filtered sodium chloride. In this activity it exhibited effects qualitatively similar to those of chlormerodrin, an organic mercurial diuretic. In addition, chlorothiazide diminished H+ and NH4+ excretion while augmenting K+ secretion within the distal segment. These are typical of the carbonic anhydrase inhibitory effects observed previously with acetazoleamide and presented in this study with dichlorphenamide. Probenecid blocked the proximal secretion of chlorothiazide but did not alter its actions on ion transport.
A rhinencephalic feeding center in the cat
Authors: Morgane P. J. , Kosman A. J.
Published: December 2017

Lesions of the rhinencephalon, primarily restricted to the pyriform lobe and amygdaloid complex, modifies the eating behavior of cats so that their food intakes and body weights are significantly increased. Neodecortication has no significant effect on either food intake or body weight whether done before or after the amygdalectomy. The amygdaloid cats eat significantly more than their controls and gain weight at a significantly more rapid rate when on an ad libitum feeding regimen. It is concluded that the amygdaloid complex constitutes some type of feeding center in the cat probably exerting its effects on more primitive lower brain stem feeding mechanisms.
Voltage field effects on muscle fiber intracellular potential form
Authors: Easton Dexter M.
Published: December 2017

Intracellularly recorded action potentials in narrow strips of frog m. adductor longus and sartorius were decreased as much as 40 mv when the external conducting volume was reduced by recording in oil. The decrease could be attributed to increased voltage effect from nearby active fibers. The field effect was simulated by means of external electrodes that provide, like the adjacent fibers, a pseudohyperpolarization during outward current through the impaled cell membrane. The typical end-plate spike form is considered to be mainly a result of field effects from nearby fiber impulses summing with the transmembrane potential of the impaled cell.
Potential difference across the pyloric antrum
Authors: Dennis Warren H. , Canosa Cipriano , Rehm Warren S.
Published: December 2017

Previous work has shown the presence of a potential difference (PD) across the fundic portion of the stomach and a smaller PD across the pyloric antrum. All of the reported measurements on the pylorus have been performed with in vitro techniques. The magnitude of the PD across the pyloric antrum was determined when its blood supply was intact. Isoelectric electrodes were placed opposite each other across the wall with isotonic saline agar making contact with the surfaces. The PD's were measured with a recording potentiometer. The average PD (mucosa negative) across the fundus, pyloric antrum and duodenum was 64 mv, 48 mv and 11 mv, respectively. There was a steep gradient of PD at the duodenal-pyloric junction. The PD of the pylorus arises from its own inherent electromotive forces. The PD like that of the fundus declines rapidly following interruption of the blood supply. The injection of Mecholyl results in a reversible decrease in the fundic potential and relatively little change in the pyloric PD.
Does a glucose load inhibit hepatic sugar output? C14 glucose studies in eviscerated dogs
Authors: Steele Robert , Bishop Jonathan S. , Levine Rachmiel
Published: December 2017

A sequence of changes in plasma glucose specific activity is observed in intact dogs when a large amount of C12 glucose is injected intravenously following the tagging of the circulating glucose by injection of a minute amount of C14 glucose. Similar changes are observed when the same procedure is applied to eviscerated dogs in which the plasma glucose concentration is being maintained by a continuous infusion of C12 glucose, this infusion being continued unchanged after the C12 glucose load is given. These results show that inhibition of hepatic glucose output is not the only or the necessary explanation for the cessation in the exponential fall of plasma glucose specific activity which is seen in the intact dog following an intravenous C12 glucose load. An alternative explanation of the effect is offered which is based on the slowness of mixing of the injected C12 glucose load with a part of the body glucose pool.
Action of carnitine on long chain fatty acid oxidation by liver
Authors: Fritz Irving B.
Published: December 2017

The addition of dl-carnitine to various types of particulate liver preparations resulted in augmented oxidation of labeled palmitate and stearate. In contrast, carnitine exerted little if any effects upon the degradation of octanoate or laurate. The oxidation of palmityl-1-C14 CoA by liver particulates was not affected by the presence of carnitine, suggesting that carnitine action is at a stage prior to the formation of this intermediate. Since carnitine addition consistently induced an increase in long chain fatty acid oxidation by slices and by subcellular particulates but did not enhance fatty acid degradation by various soluble systems, it was concluded that an intracellular structure is probably required for carnitine action. A carnitine effect on the long chain fatty acid activating enzyme could not be demonstrated. It was concluded tentatively that the site of carnitine action is independent of direct influence on the known enzymes required for fatty acid oxidation. Palmitic acid oxidation by particulate preparations was inhibited by added serum albumin or calcium, and this inhibition was in large part relieved by the addition of carnitine.
Intestinal absorption of cobalt60-labeled vitamin B12 in the normal male albino rat
Authors: Moertel Charles G. , Scudamore Harold H. , Owen Charles A. , Bollman Jesse L.
Published: December 2017

Urinary-excretion and fecal-recovery methods were employed in the study of intestinal absorption of cobalt60-labeled vitamin B12 in the normal male albino rat. a) The logarithm of the fecal excretion, as well as of the urinary excretion augmented by an intraperitoneal flushing dose of unlabeled vitamin, increased linearly with the logarithm of the oral dose. This same relation of fecal excretion to oral dose is also apparently true in man. b) Increasing the intraperitoneal flushing dose over a wide range brought about a progressive increase in the percentage of the labeled oral dose excreted in the urine, but this increase was of small magnitude. c) The optimal time for administration of the intraperitoneal flushing dose in the rat appeared to be about 2 hours after administration of the labeled oral dose. d) The male albino rat seems to be an excellent experimental animal for use in the study of vitamin B12 absorption.
Early effects of estradiol and cortisol on water and electrolyte shifts in the uterus of the immature rat
Authors: Spaziani Eugene , Szego Clara M.
Published: December 2017

The influences of estradiol on the uptake of water and radioactive electrolytes in the uterus of the immature rat were studied in short term experiments to determine the earliest manifestations of estrogen stimulation and to ascertain whether differential accumulation of these constituents occurred in the presence of the steroid. Immature rats were given a single i.v. dose of estradiol and sacrificed at intervals of 1 hour or less. Analyses of uteri for Na24 revealed: a) a short period of equilibrium followed by a gradual rise above control levels beginning at 1 hour and, b) a marked increase in the rate of uptake between the 2nd and 3rd hours, reaching a maximum 2 3/4 hours after estrogen injection. A fluid uptake occurred parallel in time and proportional in magnitude to the net accumulation of Na24. No significant change could be detected in uterine K or in the content of Na or of water in extrauterine tissues up to 6 hours following estrogen treatment. In longer term experiments, changes in uterine Na were observed and interpreted as reflecting increases in intracellular water. Cortisol blocked the increases in uterine water and Na produced at 4 hours by estradiol alone. The relationship of the results of these studies to the vascular changes induced in the uterus by estrogen is discussed.
Effect of prolonged convulsions on the blood-cerebrospinal fluid barrier
Authors: Lending Miriam , Slobody Lawrence B. , Mestern Joan
Published: December 2017

The effect of prolonged convulsions (induced by Metrazol or electroshock) on the blood-cerebrospinal fluid barrier of puppies was evaluated with the use of radioiodinated human serum albumin by measuring its rate of passage from the plasma into the cerebrospinal fluid. Albumin I131 was injected intravenously and convulsions were induced immediately by intravenous Metrazol or the application of electroshock. A marked increase in the concentration ratio (cerebrospinal fluid radioactivity/ plasma radioactivity) occurred when seizures were maintained for 30 minutes or longer. The slope of cerebrospinal fluid albumin I131 concentration as a function of time was about 25 times as great in the convulsed puppies as in the controls. It is concluded that marked alteration in the permeability of the blood-cerebrospinal fluid barrier to albumin I131 was produced by prolonged seizures.
‘Fatty acid peroxide’ formation in tissue homogenates from mice with hereditary myopathy (dystrophia muscularis)
Authors: Baker Nome , Bloom Alice , Blahd William H.
Published: December 2017

The formation of oxidation products of unsaturated fatty acids in homogenates of muscle, heart, kidney, brain and liver was studied by means of the thiobarbituric acid assay. Tissues from mice having a hereditary myopathy did not show a regular, significant increase in the formation of ‘fatty acid peroxides’ over that of normal tissues.
Effect of short-term vitamin E deficiency on guinea pig skeletal muscle myoglobin
Authors: Bender A. D. , Schottelius D. D. , Schottelius B. A.
Published: December 2017

Myoglobin concentration was determined in gastrocnemius and masseter muscles of guinea pigs maintained up to 15 days on vitamin E-deficient and vitamin E-supplemented diets. A statistically significant increase in myoglobin was noted in muscles of animals on the deficient diet for 15 days. That the increase was real and not apparent was attested by studies of total nitrogen, noncollagen nitrogen, percentage of solids and muscle wet weight, all of which were the same in control and experimental muscles. Histological sections and creatine excretion studies confirmed the impression of mild, incipient nutritional dystrophy.
Conditioned response of middle ear muscles
Authors: Simmons F. Blair , Galambos Robert , Rupert Allen
Published: December 2017

Simple and differentially conditioned responses of the middle ear muscles to visual stimuli were produced in awake cats with electrodes implanted chronically on the round windows. Muscle contractions were observed indirectly through their effects on the cochlear microphonic. These CRs are easily produced and have very short latencies (80 msec.) under optimal conditions. Somewhat longer minimal latencies (150 msec.) were measured in the differential learning situation. The stapedius was shown to play the dominant role in those conditioning experiments where only one of the two middle ear muscles was left intact.
Influence of hypoproteinemia on bile proteins
Authors: Katsuki Taketo , Johnston Charles G. , Koucky Charles
Published: December 2017

Plasmapheresis was performed in dogs to change the serum protein and bile protein. A low caloric diet and plasmapheresis resulted in a diminished plasma albumin, slightly increased α-globulin, and definitely increased ß- and γ-globulins. Simultaneously, B-fraction (albumin-containing-fraction of bile) decreased while the C-fraction (α-globulin-containing-fraction of bile) and D-fraction (ß- and γ-globulin-containing-fraction of bile) increased. When the plasmapheresis was discontinued and a normal caloric diet supplied, there was a gradual reversal of these changes toward the original levels. This is further indication that B-, C- and D-fraction of bile proteins arise from blood proteins. It is apparent that this is not by simple transudation of proteins from capillaries to bile canaliculi because the smallest protein molecular B-fraction comprises a smaller proportion of bile proteins than of serum proteins, whereas the larger molecular D-fraction comprises a larger proportion of bile proteins than of serum proteins, and yet the total bile protein concentration is always much less than the total serum protein concentration. There must be some mechanism regulating the occurrence of the bile proteins, and this may be an additional function of the hepatic cells.
Cerebrospinal fluid production and its relationship to cerebral metabolism and cerebral blood flow
Authors: Bering Edgar A.
Published: December 2017

The cerebrospinal fluid production has been studied in the dog under conditions of maximum obtainable flow rates from the cisterna magna. Under these conditions the fluid had constant composition and was assumed to represent the cerebrospinal fluid in the intact state. Cerebral blood flow and cerebral oxygen consumption were measured by the method of Kety and Schmidt. The only significant correlations found were with oxygen consumption when the CSF flow rate was in terms of brain weight and with cerebral blood flow and cerebral vascular resistance when CSF flow was in terms of choroid plexus weight. A combined regression equation was calculated which satisfactorily accounted for the observed CSF flow: CSF cu mm/min. = .128 x CMRO2 x brain wgt. + 0.15 x CVR x choroid plexus wt. This suggested separate physiological processes, one correlated with oxygen metabolism and one with hydrodynamic factors of the cerebral blood flow. The data demonstrated that the choroid plexus alone could not have accounted for the entire CSF flow and some must have come from another source, presumably the brain.
Role of medullary emetic chemoreceptor trigger zone (CT zone) in postnephrectomy vomiting in dogs
Authors: Borison H. L. , Hebertson L. M.
Published: December 2017

Latencies for vomiting following bilateral nephrectomy in control dogs, after gut denervation by transthoracic vagotomy and spinal cord transection at T4, and after ineffective ablation of the CT zone, were all within a range of 16–48 hours. By contrast, in dogs with effective lesions of the CT zone, the latency for vomiting after nephrectomy was prolonged to a range of 54–147 hours and two dogs died after 5 and 6 days, respectively, without vomiting. Chlorpromazine and morphine did not prolong the latency for vomiting after nephrectomy. Guanidine hydrochloride, 75 mg/kg i.v., evoked vomiting in all of seven control dogs, but only in one of nine dogs with effective lesions of the CT zone. Except for a more rapid decline of serum chloride in control dogs, serum sodium, potassium, bicarbonate and blood urea nitrogen followed the same pattern after nephrectomy in control and CT-zone ablated dogs.
Inhibition of anaphylactoid edema in the rat by 2-deoxyglucose
Authors: Goth Andres
Published: December 2017

The glucose analogue 2-deoxyglucose was found to inhibit the anaphylactoid reaction of rats to dextran and ovomucoid. A dose of 200 mg/kg of 2-deoxyglucose was sufficient to antagonize the effects of 60 mg/kg of dextran or 10 mg/kg of ovomucoid when these compounds were injected by the intravenous route. The reaction of rats to compound 48/80 was not inhibited. In rats pretreated with insulin larger doses of 2-deoxyglucose were required to obtain the same inhibition of anaphylactoid edema. These results and the previously demonstrated effects of insulin point to an important role of glucose permeability in certain inflammatory processes.
Variability of potassium concentration in gastric secretion
Authors: Colcher Henry , Hollander Franklin
Published: December 2017

The work of Gray and Bucher ( Am. J. Physiol. 133: 542, 1941), which led them to the conclusion that the concentration of K in histamine-stimulated gastric secretion from canine vagotomized pouches is constant around 7.4 mEq/l., was repeated with only minor modification. The stimulus was administered either in a series of small subcutaneous doses repeated every 10 minutes, or in a single larger dose injected after termination of the former. Regardless of procedure, the experiments revealed a range in [K]-values of considerable magnitude, extending both above and below the level characteristic of normal canine serum; for the entire study, the lowest concentration observed was 1.6, the highest 11.2 mEq/l. Although these variations were systematic, they were not definitively correlated with acidity, [Na] or [Cl]. Hence, the inference that 7.4 mEq/l. characterizes the [K] of both the primary acid secretion and the non-acid mucous secretion is likewise invalidated. This conflict between our data and those obtained by Gray and Bucher is shown to result from two defects in their experimental design: a) they discarded all secretion collected during the first 60-minutes—an interval which gives rise to many of the [K] values well above 7.4 mEq/l.; and b) they used pooled specimens, regardless of experiment and—in most cases—of dog. The significance of these variations in [K] will be considered in a subsequent publication.