bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiovascular studies on normal calves
Authors: Kuida Hiroshi , Brown Arthur M. , Lange Ramon L. , Hecht Hans H.
Published: December 2017

Physiologic measurements of several circulatory parameters were made in 15 normal unanesthetized calves by cardiac catheterization. Fifty-four observations were made in the ‘resting’ state during 27 separate studies. The calves were restrained in the right lateral decubitus position in a calf chute. Oxygen consumption (Vo2) was measured by collecting expired air through a cuffed endotracheal tube. Cardiac output was determined by the direct Fick (Q·f) and/or the dye dilution (Q·d) techniques. Pulmonary artery (PAP), right heart and carotid artery (CAP) pressures were measured routinely while pulmonary artery wedge, left ventricular and central aortic pressures were obtained in a few animals. Under the conditions of the study, it is unlikely that the animals were in a truly resting state. However, absence of a statistically significant difference between two consecutive measurements of various parameters in 11 studies and good agreement between 17 paired Qf and Qd determinations suggests that the animals were in a reasonably steady state. Mean ± Sx values of the more important parameters measured were as follows: Qd 7.30 ± 0.23, Qf 7.10 ± 0.42 l/min/m2; Vo2 365 ± 29 cc/min/m2; PAP 21.6 ± 1.4, CAP 131 ± 4.5 mm Hg; pulmonary vascular resistance 2.34 ± 0.27 mm Hg/l/min/m2.
Effect of body temperature change on cerebral oxygen consumption of the intact monkey
Authors: Bering Edgar A.
Published: December 2017

The cerebral oxygen consumption of monkeys ( Macaca mulatta) has been measured with the animals' rectal temperatures varying from 19° to 37° C. The animals were allowed to remain at the experimental temperature for 1 hour before oxygen consumption studies were done. Cerebral oxygen consumption was calculated using the Kety-Schmidt nitrous oxide technique for measuring cerebral blood flow. A linear relationship was found between the logarithm of the cerebral oxygen consumption and the reciprocal of the absolute temperature (°K) of the body. This held over the entire temperature range studied with a standard deviation about equal to that of the method for measuring the cerebral oxygen consumption.
Effects of metabolic acidosis and alkalosis on coronary blood flow and myocardial metabolism in the intact dog
Authors: Goodyer A. V. N. , Eckhardt W. F. , Ostberg R. H. , Goodkind M. J.
Published: December 2017

Severe metabolic acidosis and alkalosis were induced in anesthetized dogs by the infusion of solutions of hydrochloric acid and sodium bicarbonate. Infusions of sodium chloride were administered to other dogs under the same experimental circumstances. Measurements were made of arterial blood pressure, heart rate, cardiac output and coronary blood flow, arterial blood pH, and the content of oxygen, total CO2, lactate, pyruvate and glucose in both arterial and coronary venous blood. The cardiac output and coronary blood flow were decreased by acidosis and increased by alkalosis, the changes induced by alkalosis. There were no significant changes of left ventricular efficiency. Acidosis increased blood glucose concentrations and interfered with the increased myocardial uptake of glucose expected at higher arterial glucose levels. Alkalosis increased blood lactate and pyruvate levels and, correspondingly, the myocardial uptake of these carbohydrate substrates. It is concluded that cardiac dynamic function (as indicated by measurements of cardiac efficiency and output and arterial pressure) is much less affected by severe metabolic acidosis in the intact animal than in the isolated perfused organ.
Nitrogenous substances in udder lymph and plasma of cattle
Authors: Heyndrickx G. V.
Published: December 2017

Urea and uric acid were determined chemically and 10 amino acids chromatographically in udder lymph and plasma of the udder veins of cattle. From the results, it appears that urea occurs in the same concentration in the two fluids while uric acid and each of the 10 amino acids are considerably higher in the lymph than in the plasma. As a percentage of total amino nitrogen however, glycine and tyrosine occur in a significantly ( P = 0.01) lower concentration in lymph than in plasma, while the reverse is true for the leucines, lysine and also for threonine, but only at P = 0.05 for the latter. Highly significant correlations have been established between glycine, leucines and valine in lymph and in plasma.
Age effect on cell-transit time in mouse jejunal epithelium
Authors: Fry R. J. M. , Lesher S. , Kohn H. I.
Published: December 2017

Epithelial cell renewal in the jejunum of CAF1 mice was studied by observing the time for cells labeled with tritiated thymidine (1.5–2.0 µc/g body wt.) to pass from the crypt to the extrusion zone at the tip of the villus. Mice of three ages were studied: 93, 372, and 940 days. The total observed transit times were 44, 52, and 53 hr, respectively. The increase with age was the result of increase in both the crypt and villus transit times. Structural changes could not be made to account for the differences. The increase may be the result of a decreased rate of cell production in the crypts.
Further evidence for the unimportance of renal autoregulation
Authors: Langston Jimmy B. , Guyton Arthur C. , Hull C. C. , Armstrong G. G.
Published: December 2017

Previous experiments from this laboratory indicated that normal kidneys may not have significant intrinsic ability to autoregulate their blood flow when renal arterial pressure is varied. However, in these earlier studies, the renal blood flow was less than that generally accepted as normal, and there was a possibility that the renal circulation had not been completely isolated. This could have resulted in extrarenal blood flow during the pressure-flow study. In the present experiments, renal blood flows were in the normal range at all pressure levels. This difference was achieved by rendering the animals areflex prior to the laparotomy. The pressure-flow relationship was studied under these conditions, and the resulting curves were slightly concave to the pressure axis in the lower pressure range, indicating only a mild degree of autoregulation, approximately the same degree as that found in other tissues. However, the renal blood flow still increased rapidly with each increase in perfusion pressure even in the range of so-called autoregulation. It was also shown that all the blood that passed through the perfusion system also passed through the kidney, eliminating the possibility of extrarenal blood flow.
Contents and distributions of potassium, sodium, and chloride in uterine smooth muscle
Authors: Kao C. Y.
Published: December 2017

For the immature uterus the water, potassium, sodium, and chloride (per kg wet tissue) are 838 g, 101 mEq, 87 mEq, and 67 mEq, respectively; for isolated myometrium under estrogen domination they are 799 g, 109 mEq, 79 mEq, and 67 mEq, respectively; for isolated myometrium under progesterone domination they are 792 g, 111 mEq, 83 mEq, and 72 mEq, respectively. Potassium contents are higher than those reported previously by other investigators, owing to a technique of preparation that avoided leaching of K from the tissues. Extracellular spaces estimated by distributions of inulin are 327 ml/kg for immature uterus, 322 ml/kg for estrogen-dominated myometrium, and 312 ml/kg for progesterone-dominated uterus. There is little statistically significant difference between extracellular spaces or ion content of the different hormonally affected uterus or myometrium. In estrogen-dominated myometrium, 14 mEq/kg of K and 29 mEq/kg of Na are unextractable in neutral isotonic sucrose. In progesterone-dominated myometrium, they are 4 and 9 mEq/kg, respectively. After correction for unextractable fractions, the sum of intracellular Na, K, and Cl in estrogen-dominated myometrium is in fair agreement with the total osmolar concentration of serum, but in progesterone-dominated myometrium it is still greater than the total osmolar concentration of serum.
Mitochondrial swelling during cold exposure of the rat and hamster
Authors: Boatman Joseph B. , Boucek Marie M. , Rabinovitz Marvin J.
Published: December 2017

Swelling of isolated liver mitochondria of hamsters and rats was measured in a Beckman DK ratio-recording spectrophotometer after 0, 1, 2, 5, 10, 15, and 20 days of cold exposure at 5 C. Swelling was determined by absorbance changes over 10-min intervals at 520 mµ at 37 C in 0.3 m sucrose with and without 1.5 x 10–7 m l-thyroxin added. Thyroid uptake and plasma content of 0.5 µc I131 was measured in additional animals at 2, 6, 18, 48, and 144 hr of cold exposure. Swelling rates of rat liver mitochondria increased with time, while hamster liver mitochondria showed no change during 20 days of exposure to cold. Added thyroxin increased swelling rates equally of both rat and hamster liver mitochondria, reducing the early refractory period of the swelling curve. Rat thyroid uptakes of I131 were higher at room temperature than the hamster. Cold exposure resulted in a severe reduction of hamster thyroid uptake of I131 while reduction of rat thyroid uptake was minor. Differences in mitochondrial response to swelling media between the cold-exposed hamster and rat paralleled the different functional levels of the thyroid during cold exposure.
Platelet size, ATP content, and clot retraction in relation to platelet age
Authors: Detwiler T. C. , Odell T. T. , McDonald T. P.
Published: December 2017

The in vivo aging of rat blood platelets has been studied by comparing the ability to promote clot retraction, size, and ATP content of young, old, and normal populations of platelets. Young platelets were obtained 2 days after injecting rats with antiplatelet serum. Old platelets were obtained by incubating fresh platelets for 2 days in rats made thrombocytopenic by 900 r of whole-body X irradiation. There was a decrease with age in the size of platelets of about 25% between young and old. There was no statistically significant age-related difference in the content of ATP when expressed as micromoles of ATP/1011 platelets or micromoles of ATP/ml of packed platelets. The clot-retracting ability of old platelets was about 10% less than that of young platelets. Constancy of ATP on the basis of both platelet number and platelet volume is not consistent with a change in platelet size. It seems probable that there was a decrease in micromoles of ATP/platelet, although it was not statistically significant. The reduction in clot retraction may be due to a small decrease in the size of the ATP pool or to an impairment of the platelet's ability to metabolize glucose for the production of the additional ATP necessary for clot retraction.
Mechanism of depression of reticuloendothelial system in shock
Authors: Blattberg Benjamin , Levy Matthew N.
Published: December 2017

Phagocytic activity of the reticuloendothelial system (RES) in anesthetized, splenectomized dogs was assessed by measuring clearance of carbon particles from the blood. Hemorrhagic hypotension for 90 min at 40 mm Hg resulted in a significant depression of RES activity. Autoperfusion of the liver with arterial blood at approximately normal flow rates during hypotension did not prevent depression of the RES. Therefore, decreased phagocytic activity cannot be ascribed entirely to ischemia of this tissue, and, by exclusion, it is likely that humoral factors may be involved. In hypotensive groups, liver perfusion did not significantly affect mortality rate. Furthermore, there was no apparent relationship between survival rate and degree of depression of the RES.
Salivary gland changes after isoproterenol-induced enlargement
Authors: Schneyer Charlotte A.
Published: December 2017

Salivary glands and cardiac ventricles were examined after chronic administration of pharmacological doses of isoproterenol (ISO) to young adult female rats. Enlargement of glands was observed, generally confirming previous reports. Enlargement of ventricles also occurred. Salivary glands were differentially affected, with parotid showing the most, and sublingual the least enlargement. Histological examination revealed increase in cell size sufficient to account for the increase in organ weight, although some mitotic activity was noted. Determination of water, electrolyte, and amylase content of glands indicated the hypertrophy is not due simply to water imbibition; changes in gland composition, when seen, were generally reminiscent, in magnitude and direction, of those occurring ordinarily during function activity. Function after chronic treatment with ISO was little affected; reduction in flow rate after pilocarpine was the major change observed in enlarged glands. Changes in gland and ventricle size and gland composition and function, induced by chronic ISO treatment, were largely reversible by withdrawal of the drug. It appears that in the adult, isoproterenol effects increases in organ size mainly by increase in cell size.
Phasic efflux of potassium from frog ventricle
Authors: Lorber Victor , Walker John L. , Greene Ernest A. , Minarik Margaret H. , Pak Moon Jae
Published: December 2017

A phasic effiux of K42 during the cardiac cycle, first described by Wilde in the turtle heart, has been observed in perfused strips of frog ventricle. This was shown to represent an actual increase in the outward movement of K, occurring during the action potential, and of approximately the same duration as the electrical transient. Perfusion with K-free Ringer's prolonged both events, and, within the limits of resolution of the method, appeared to do so to about the same extent. The level of K in the perfusion medium was found to have a pronounced effect on the K efflux, a result which may be interpreted in terms of an effect of extracellular [K+] on the permeability of the cell membrane to K. The finding that the increase in K efflux observed during the action potential is much smaller than that predicted from the increase in the voltage gradient (assuming the voltage gradient to be the only variable) is consistent with a diminished K conductance during the action potential.
Failure to show change in rat tissue histamine and serotonin after rapid decompression
Authors: Kindwall Eric P. , Boréus Lars Olof , Westerholm Barbro
Published: December 2017

Albino rats were subjected to rapid decompression from high ambient pressure (6 atm). The mean levels of histamine and 5-hydroxytryptamine in skin, ileum, lung, and brain were measured. They showed no significant change as compared to a nondecompressed control group even when decompression time was short enough to cause immediate death. The decompression also failed to produce any changes in the morphological appearance of the mesenteric mast cells.
Autocatalysis in prothrombin activation
Authors: Seegers Walter H. , Marciniak Ewa , Cole Edmond R.
Published: December 2017

Two enzymes, thrombin and autoprothrombin C, are derived from purified prothrombin by autocatalytic activation in 25% sodium citrate solution. The thrombin but not the autoprothrombin C activity is destroyed by diisopropylfluorophosphate. Autoprothrombin C is a procoagulant, which catalyzes the conversion of prothrombin to thrombin in a prothrombin-activating mixture consisting of calcium ions, Ac-globulin, and crude cephalin. Depending upon the amount of p-toluenesulphonyl-l-arginine methyl ester added to the prothrombin-activation mixture the thrombin generation may be retarded or inhibited completely. The view is expressed that all prothrombin activations are fundamentally autocatalytic. The end products of prothrombin activation involved are autoprothrombin C and thrombin, while the intermediate products of prothrombin activation are the autoprothrombins.
Diffusion of glucose through blood-cerebrospinal fluid barrier in normal dogs
Authors: Williams R. D. B. , McCord Augusta
Published: December 2017

Hyperglycorrachia was produced in anesthetized dogs by the administration of intravenous glucose. The glucose entered the lumbar subarachnoid space more rapidly than it entered the cisternal subarachnoid space. This finding is a reverse of the diffusion into the cisternal and lumbar regions in man after the administration of intravenous glucose. The pattern in dogs is different from that in man under normal circumstances, but follows the pattern present when radioactive sodium 24 is used as a diffusible substance. It is concluded that glucose diffuses directly into the spinal subarachnoid at a rapid rate in the dog. This may be due to anatomical differences in various species.
Blood flow from and oxygen uptake by muscle, during and after partial venous occlusion
Authors: Fales John T. , Heisey S. Richard , Zierler Kenneth L.
Published: December 2017

In dog gastrocnemius-plantaris muscle in situ, effects of partial venous occlusion and its release were compared to effects of arterial occlusion and release. During partial venous occlusion, blood flow decreases, arteriovenous oxygen difference is constant, and oxygen consumption is, therefore, reduced proportionately to blood flow. On release of partial venous occlusion, unlike release of arterial occlusion in which both blood flow debt and oxygen debt are repaid, there is little or no repayment of blood flow debt, arteriovenous oxygen difference remains constant, and there is, therefore, little or no repayment of oxygen debt. These effects of partial venous occlusion are reminiscent of those reported to occur during and after release of passive stretch of circulated muscle, and it is proposed that the stretch effect is secondary to venular occlusion. The observations are consistent with the hypothesis that, within limits, muscle oxygen consumption is dependent on or limited by blood flow.
Systemic oxygen transport in induced normovolemic anemia and polycythemia
Authors: Murray John F. , Gold Philip , Johnson B. Lamar
Published: December 2017

The hemodynamic effects of normovolemic anemia and polycythemia were studied in 14 dogs. Anemia (5 dogs) and polycythemia (5 dogs) were induced by bleeding and simultaneously infusing dextran or packed erythrocytes. Measurements included cardiac output, arterial oxygen saturation, peripheral vascular resistance, and systemic oxygen transport (cardiac output X arterial oxygen content). Cardiac output had a significant negative linear relationship to hematocrit ( r = –0.74, P < 0.01) over the range studied (13–74%). Peripheral resistance fell 46% in anemic animals and increased 152% in four of five polycythemic animals. Arterial saturation was significantly correlated to changes in hematocrit ( r = 0.62, P < 0.01) and cardiac output ( r = –0.55, P < 0.01); these values were due primarily to the linearity encountered in the anemia experiments and a reversal in these relationships tended to occur at high hematocrits. Systemic oxygen transport was maximum at normal hematocrits and decreased in anemia and polycythemia. The data indicate that hemodynamic adjustments in normovolemic anemia and polycythemia are insufficient to maintain normal oxygen delivery.
Effects of surfactants or fat solvent on static pressure-volume hysteresis of excised dog lung
Authors: Yoshida Seiichi
Published: December 2017

The static pressure-volume diagram of the lung was studied after the application of surface active agents to the airways of excised lobes of dog lungs. After rinsing of excised air-free lobes with saline or plasma, hysteresis obtained on air inflation and deflation was marked, but it was remarkably reduced after rinsing air-free lobes with surface active agents, 0.5% Tween-20 in saline, 0.5% octyl alcohol in plasma, or with petroleum ether. The reduced hysteresis was accompanied by a diminution in the amount of air remaining in the lobe on return to zero intrabronchial pressure level. The results of the surface tension-area relationship of lung extracts are consistent with those of the pressure-volume characteristics of lungs. These data indicate that the change in slope and position of the deflation curve resulting from fixing surface tension at about 25 dynes/cm, reduces hysteresis, in correspondence with the reduction of the volume of trapped air at zero intrabronchial pressure level.
Approach-escape interactions in rat brain
Authors: Olds M. E. , Olds J.
Published: December 2017

Animals with electrodes implanted at tegmental escape points and at hypothalamic approach points were tested for positive reinforcement during simultaneous negative stimulation, and for escape behavior during simultaneous positive stimulation. The test of positive reinforcement was made by presenting a correlated hypothalamic stimulus after each lever response, during a 2-min period, while a constant train of stimulation was being applied to a negative reinforcing point in tegmentum. The test of negative reinforcement was made by presenting repeated 1/2-sec trains of tegmental stimulation at a rate of 1/sec and interrupting this sequence for 4 sec after each lever response, during a 2-min period, while a constant train of stimulation was being applied to the positive reinforcing point in lateral hypothalamus. The constant negative train impeded and sometimes inhibited completely the positively reinforced behavior. The constant positive train, however, far from impeding the escape response, regularly facilitated the negatively reinforced behavior. The data were interpreted on the theory of a one-way inhibition from tegmental escape points to the hypothalamic approach one.
Course of deuteriation and some physiological effects of deuterium in mice
Authors: Katz Joseph J. , Crespi Henry L. , Czajka Dorice M. , Finkel Asher J.
Published: December 2017

The course of deuteriation was followed in mice given various concentrations of D2O in the drinking water. Equilibrium deuteriation in the body fluids is 95% attained by the 10th day, and from these values the experimental conditions leading to desired levels of deuteriation in mice are readily specified. The incorporation of deuterium into liver, kidney, and spleen reaches equilibrium by the 3rd week. Incorporation of deuterium into brain is much slower but eventually reaches approximately the same value. Median survival times for mice deuteriated at various D2O levels in the drinking water range from 60 days, for mice drinking 40% D2O, to 12 days for mice drinking 75% D2O.
Blood coagulation in fish
Authors: Doolittle Russell F. , Surgenor Douglas M.
Published: December 2017

Blood coagulation systems in cyclostome, elasmobranch, and teleost fish were studied and compared. The plasma of all these fish contained a fibrinogen molecule, capable of being clotted by human thrombin, and a prothrombin molecule, capable of being converted into thrombin which could hydrolyze p-tosyl l-arginine methyl ester. The prothrombin activity could be adsorbed on barium sulfate. Accurate assessment of prothrombin conversion factors is confounded by the "species specificity" of protein-protein interactions, but preliminary observations were made on both the extrinsic and intrinsic clotting schemes. Fish thrombocytes play a central role in the intrinsic conversion of prothrombin to thrombin, and are responsible for clot retraction. The plasma of the smooth dogfish exemplifies a clotting diathesis which can be overcome in vitro by the addition of large amounts of calcium. Under such conditions, other parts of the coagulation scheme become greatly exaggerated, and a very large thrombin generation ensues, subsequently followed by an intense fibrinolysis. A powerful serum inhibition occurs which was shown to be caused by the breakdown products of the fibrinolysis.
Circulating red cell volume in little brown bats in summer
Authors: Kallen Frank C. , Wimsatt William A.
Published: December 2017

Circulating erythrocyte (RBC) volumes were determined in the little brown bat, Myotis lucifugus, by using a Cr51-labeling procedure. In 5 min, mixing of labeled cells was 97% complete in active bats and remained so for up to 1 hr after injection, owing to RBC retention by the spleen. Mixing for 5 min appeared less complete when lactating bats were placed in a hibernating environment; the torpor induced in such bats differed from winter hibernation. From late pregnancy to postlactation, active bats averaged 4.4 ml RBC/ 100 g body wt. Blood volume calculated from RBC volume and plasma volume was 11.1 ml/100 g body wt. The per cent RBC in blood samples fell during lactation. High cell volume was associated with high body weight in postlactation bats, but not during late pregnancy or lactation. Some bats had a lower RBC volume after delivery, but a significant cell volume decrease in all bats was not evident until lactation had ceased. Cell volume in late pregnancy was only 17% above that of postlactation bats. No lactation polycythemia was noted.
Fibrinogen titer as an indicator of physiologic stability
Authors: McKenzie J. M. , Celander D. R. , Guest M. M.
Published: December 2017

A semimicro method was developed and used to determine the levels of fibrinogen in two groups of dogs. One group was obtained from the dog pound and their plasma fibrinogen levels were determined immediately. The other group was kept in the departmental animal quarters under conditions essentially free of environmental stress for 45 days before determining the plasma fibrinogen concentration. The concentration of fibrinogen was found to be significantly lower in the group which was housed in the departmental quarters. However, when representative individuals from the latter group were subjected to intermittent electrical stimuli of low intensity for periods of 3–11 days the plasma fibrinogen increased significantly. It thus appears that the concentration of plasma fibrinogen is directly related to the degree of stress to which animals have been subjected and the stress initiating the response need not cause overt tissue damage.
Extraction of amino acids from and their addition to renal blood plasma
Authors: Shalhoub R. , Webber W. , Glabman S. , Canessa-Fischer M. , Klein J. , deHaas J. , Pitts R. F.
Published: December 2017

Twenty paired samples of arterial and renal venous plasma, collected simultaneously from dogs in ammonium chloride acidosis, were analyzed by column chromatography for 23 α-amino acids. Fifteen additional paired samples from dogs in acute metabolic alkalosis were similarly analyzed. In ammonium chloride acidosis, glutamine plus asparagine, glycine, citrulline, tryptophan, and proline are extracted from renal blood plasma. Alanine, serine, glutamic acid, cystine, and ornithine are added to renal venous plasma. The addition of glutamic and aspartic acids amounts only to 4% of the extraction of glutamine plus asparagine. It is, therefore, probable that both α-amino and amide nitrogens are removed from the parent amide molecules. In acute metabolic alkalosis, the extraction of glutamine plus asparagine is halved, on an average. The extraction of glycine and the addition of alanine and serine are essentially unchanged. Therefore, only the extraction of glutamine plus asparagine varies to a quantitatively significant degree with changes in acid-base balance which markedly alter the rate of excretion of ammonia.
Cardiac nucleotides in hypoxia: possible role in regulation of coronary blood flow
Authors: Berne Robert M.
Published: December 2017

Experiments were performed on isolated cat hearts perfused with Tyrode's solution and intact hearts of open-chest dogs. Cardiac hypoxia resulted in a decrease in coronary vascular resistance and a release of significant amounts of inosine and hypoxanthine from the myocardium. From 3 to 27 times more inosine and hypoxanthine were released from the heart during myocardial hypoxia than were required to double the coronary blood flow when infused as adenosine into the left coronary artery. Based on the assumption that with hypoxia the nucleotide derivatives leave the myocardial cell as adenosine, an hypothesis is proposed for the metabolic regulation of coronary blood flow.
Eye movements induced by ampullary nerve stimulation
Authors: Cohen Bernard , Suzuki Jun-Ichi
Published: December 2017

Powerful neural pathways from semicircular canals to eye muscles were activated by double pulses delivered to ampullary nerves. The effectiveness of this stimulation was due to a facilitatory cycle which followed each ampullary nerve stimulus. Facilitation was maximum 2.5–3 msec after a particular stimulus and lasted for 15–20 msec. Successive stimuli which fell during maximum facilitation evoked extraocular muscle potentials which would follow pulse trains synchronously up to 250–300/sec. Eye movements followed pulse trains up to 100/sec. The amplitude of the induced eye movements could be increased by increasing the strength or number of pulses in a train. Longer lasting facilitation occurred with repetitive stimulation and alerting. Repetitive stimulation produced slow eye deviations. In the monkey and in some cats this deviation developed into nystagmus and was followed by an oppositely directed afternystagmus. Small doses of Nembutal decreased facilitation and abolished nystagmus and afternystagmus.
Micropuncture study of composition of proximal and distal tubular fluid in rat kidney
Authors: Ullrich Karl J. , Schmidt-Nielsen Bodil , O'Dell Roberta , Pehling Gundula , Gottschalk Carl W. , Lassiter William E. , Mylle Margaret
Published: December 2017

Fluid was collected by micropuncture from proximal and distal convolutions of anesthetized rats and analyzed for inulin, sodium, urea, and total osmotically active solute. The proximal fluid/plasma (F/P) sodium ratio was not significantly different from unity in antidiuretic animals, but was as low as 0.78 during mannitol diuresis. The distal F/P sodium ratio averaged 0.62 in antidiuresis, and 0.24 during osmotic diuresis. The data are interpreted to indicate active sodium transport by both proximal and distal convolutions. The F/P ratios for inulin, urea, and total osmotically active solute are in general agreement with previous studies.
Micropuncture study of composition of loop of Henle fluid in desert rodents
Authors: Gottschalk Carl W. , Lassiter William E. , Mylle Margaret , Ullrich Karl J. , Schmidt-Nielsen Bodil , O'Dell Roberta , Pehling Gundula
Published: December 2017

Using micropuncture techniques, fluid was collected from loops of Henle at the tip of the renal papilla in anesthetized hamsters and Psammomys, and its composition compared with that of collecting duct urine. The osmolalities of the two fluids were essentially the same. Sodium and attendant anions constituted 64% and urea 19% of the osmotically active solute in loop fluid. In collecting duct urine, urea was the major solute present, and sodium was present in low concentration. Inulin ratios indicated that 9% of the filtered water reached the tip of these loops at a time when 0.9% was in the final urine. The data support the countercurrent hypothesis for urine formation.
Effect of sound on the hypothalamic-pituitary-adrenal axis
Authors: Henkin Robert I. , Knigge Karl M.
Published: December 2017

In the rat, the stress of exposure to continuous, high intensity sound (130 db, 220 cycles/sec) evoked a pattern of adrenocortical response consisting of an initial, immediate high rate of hormone secretion (determined in adrenal venous blood by chromatographic techniques), a subsequent period of depression of corticosterone output to normal or subnormal levels, and eventual return of hormone secretion to high levels. The period of suppressed corticosterone secretion appeared dependent upon the continuous presence of the stressor for a period of 12 hr. The data suggest that the depression of corticosterone secretion is due to inhibition of secretion of ACTH. Bilateral surgical destruction of the middle ear of the animals abolished the response pattern. After placement of bilateral lesions in the posterior hypothalamus, the resting rate of corticosterone secretion was significantly greater than normal and the response pattern was markedly attenuated.
Inhibitory effects of cardiac glycosides and adrenal steroids on amino acid transport
Authors: Kostyo J. L. , Schmidt J. E.
Published: December 2017

The cardiac glycosides, ouabain, scillaren, and scilliroside, inhibit the transport of α-aminoisobutyric acid (AIB) into isolated intact rat diaphragm when present in the medium at a concentration of 10–3 m. Lower concentrations of the glycosides do not inhibit AIB uptake, but cause marked shifts in the distribution of sodium and potassium in the diaphragm. Decreasing or increasing the concentration of potassium in the medium does not markedly alter the ability of ouabain to inhibit amino acid transport, although high extracellular potassium alone causes inhibition of AIB uptake. Ouabain does not alter the ATP content of the diaphragm. For these and other reasons which are discussed, the inhibitory effects of cardiac glycosides on AIB transport appear to be independent of their effects on ion transport, and not related to a possible action on limiting the ATP supply of the cell. It is suggested that their action on amino acid transport may be related to their structural similarity to steroid hormones, which also inhibit amino acid transport. Corticosterone, deoxycorticosterone, and aldosterone inhibit AIB transport when present in vitro at concentrations in the micromolar range. The possible physiological significance of this in vitro effect of adrenal steroid hormones is discussed.
Potassium-induced contracture and calcium exchange in the guinea pig's taenia coli
Authors: Chujyo Nobuyuki , Holland William C.
Published: December 2017

High potassium (40 mm)-induced tension declined after calcium concentration in the medium (Ca0) was reduced below 1.25 mm, reaching equilibrium level which was dependent on Ca0. High K applied after reduction of Ca0 (0.156–0.94 mm) caused a transient tension rise followed by decline to the same equilibrium level as above. In the presence of 2,4-dinitrophenol (0.3 mm), a transient contraction occurred after high K followed by a decline to a low equilibrium tension which was not dependent on Ca0 (0.156–2.5 mm). Rate constants of Ca45 outflow were not markedly affected by high K. Ca45 uptake and exchangeable fraction of cellular Ca increased with high K. Results suggest the release of Ca during K contracture.
Activation of phosphorylase in toad bladder and mammalian kidney by antidiuretic hormone
Authors: Handler Joseph S. , Orloff Jack
Published: December 2017

An increase in phosphorylase activity has been demonstrated in the intact urinary bladder of the toad and in slices of rabbit renal medulla and dog renal cortex and medulla incubated in vitro with vasopressin. A similar response occurred in the toad bladder incubated with adenosine-3',5'-monophosphate (cyclic-3',5'-AMP). Phosphorylase activation in the bladder was also produced by incubation with oxytocin or protopituitrin, but not by incubation with ACTH or epinephrine. The metabolic significance of hormone-induced phosphorylase activation is unclear. However, since activation of phosphorylase is a characteristic tissue response to hormones that act through cyclic-3',5'-AMP, the present observations support the suggestion that vasopressin alters the permeability to water of the urinary bladder of the toad and mammalian kidney through a pathway involving stimulation of the production of cyclic-3',5'-AMP.
Lipoprotein lipase activity in human heart
Authors: Schnatz J. David , Ormsby John W. , Williams Robert H.
Published: December 2017

Human ventricular tissue was obtained 11–28 hr post mortem, homogenized in ammonium hydroxide, and tested for its ability to catalyze the hydrolysis of an "activated" cottonseed oil emulsion. Lipolysis, as indicated by a rise in fatty acids, occurred in the presence of a freshly prepared homogenate, but not in the presence of a boiled homogenate. Sodium chloride, 1 m, inhibited the reaction, but sodium fluoride, 0.2 m, did not. An activated cottonseed oil emulsion was more readily hydrolyzed than a "nonactivated" cottonseed oil emulsion. Approximately 50% of the activity of the homogenate sedimented at a gravitational force produced by centrifugation at 800 g for 10 min. The conclusion is that human heart tissue, like animal heart, contains lipoprotein lipase activity and that this activity is associated, in part, with the heavier cellular particles.
Effect of carbonic anhydrase inhibition on proximal tubular bicarbonate reabsorption
Authors: Clapp James R. , Watson John F. , Berliner Robert W.
Published: December 2017

Samples of fluid from the proximal tubule were collected for the measurement of pH and bicarbonate concentration before and after the administration of acetazolamide (Diamox). Samples collected before acetazolamide were consistently more acid than plasma with the most acid samples coming from the more distal portion of the proximal tubule. After the intravenous administration of acetazolamide, the pH and bicarbonate concentration were consistently higher than in plasma. Bicarbonate concentrations as high as 2.8 times that in plasma were observed. The rise in proximal tubular fluid bicarbonate concentration after acetazolamide is presumably due to a reduction in the rate of bicarbonate reabsorption out of proportion to any impairment in proximal tubular fluid volume reduction.
Sex difference in resting pituitary-adrenal function in the rat
Authors: Critchlow V. , Liebelt R. A. , Bar-Sela M. , Mountcastle W. , Lipscomb H. S.
Published: December 2017

Resting levels of plasma and adrenal corticosteroids, pituitary content of adrenocorticotropin, and circulating leukocytes were determined at intervals during controlled 24-hr light-dark cycles in intact, castrated, sham-castrated adult and prepubertal male and female rats. To study the influence of environmental lighting rhythms, corticosteroid levels were similarly followed in intact and blinded male and female rats and in ovariectomized females following a 9-hr shift in lighting regimen. All groups of animals showed evidence of cyclic pituitary-adrenal function, but the presence of mature ovaries was associated with marked facilitation of the diurnal excursions in corticosteroid levels. Furthermore, the results indicated that the mechanisms responsible for pituitary-adrenal rhythmicity are influenced by cyclic ovarian function, are sensitive to pentobarbital, and are synchronized by environmental lighting rhythms perceived through the eyes. Several of the features of pituitary-adrenal function under resting conditions resemble those associated with cyclic release of gonadotropin leading to ovulation. Similar or overlapping neural mechanisms may be responsible for these endocrine rhythms.
Antiphlogistic action of granuloma pouch exudates in intact or adrenalectomized rats
Authors: DiPasquale G. , Girerd R. J. , Beach V. L. , Steinetz B. G.
Published: December 2017

Injection of lyophilized granuloma pouch exudate inhibited the formation of cotton pellet granulomas in rats. In contrast, lyophilized serum, obtained from rats bearing granuloma pouches, did not exert measurable anti-inflammatory effects. The antiphlogistic activity was not dependent upon the time of pouch development at which the exudates were harvested, and thus did not appear to be derived from the systemic circulation. Unlike ACTH, the exudates failed to elevate plasma-corticosteroid levels in hypophysectomized rats. The exudates exerted significant anti-inflammatory activity in adrenalectomized rats, and these effects were enhanced by concomitant treatment with small doses of whole adrenocortical extract (ACE). The exudates themselves contained little or no corticosterone or cortisol. Thus, the anti-inflammatory properties of pouch exudates do not appear to depend upon contained ACTH or adrenalcorticoids. In contrast to glucocorticoids, anti-inflammatory doses of exudate had no adverse effect on body weight gain. This fact, together with the observed synergism of exudate and ACE in reducing inflammation, suggests that the mechanisms of action of exudate and glucocorticoids may be different.
Osmolality of brain tissue and its relation to brain bulk
Authors: Stern W. Eugene , Coxon R. V.
Published: December 2017

Changes in the osmolality of the blood plasma of guinea pigs were induced by peroral hydration, coupled with injections of Pitressin, by peritoneal dialysis, and by hypertonic intravenous infusions. Using freezing-point determinations on homogenates the effects of these changes upon the osmolality of the tissue fluids of the brain were investigated. The water content of the brain and its sodium and potassium content were also measured. It was found that a rise or fall in plasma tonicity exceeding about 45 mosmoles/kg water was accompanied by a change of osmolality of the tissue fluids of the brain in the same direction and by a corresponding loss or gain of water. The water movements were sufficient to produce variations in the bulk of the brain which might critically affect intracranial volume-pressure relationships. In untreated animals the osmolality of the brain fluids appeared to be somewhat greater than that of plasma.
Thermogenesis of brown adipose tissue in cold-acclimated rats
Authors: Smith Robert E. , Roberts Jane C.
Published: December 2017

Multilocular brown adipose tissue in the rat is shown to increase in both mass and respiratory rate, in vitro, during cold acclimation. By vascular convection the resulting heat is directly applied to the thoracocervical regions of the spinal cord, the heart, and other thoracic organs. The vasculature is so arranged as to exercise a fine order of thermogenic control over the brown fat and temperature of the peripheral venous returns to the thorax, facilitated in part by a "reverse" type of countercurrent heat exchange apparently not previously described.
Effect of bioflavonoids and methylprednisolone on collagen biosynthesis
Authors: Bavetta Lucien A. , Nimni Marcel E.
Published: December 2017

The administration of different citrus bioflavonoids to the rat failed to demonstrate anti-inflammatory effects when judged by their influence on the rate of collagen synthesis around subcutaneously implanted polyvinyl sponges. These compounds were administered orally, applied locally at the time of implantation, or injected either at the site of granulation or subcutaneously. Treatment with methylprednisolone (0.016 mg/day rat) retarded growth and inhibited collagen synthesis. However, bioflavonoids given to these animals were able to counteract partially or completely the inhibitory effects of the steroid on collagen formation. The efficacy of the bioflavonoid in this connection was related to its nature and route of administration.
Arterial Pco2 and cerebral hemodynamics
Authors: Reivich Martin
Published: December 2017

The effect of arterial Pco2 in the control of cerebral hemodynamics over the full range of responsiveness of the cerebral vasculature was studied in the rhesus monkey. Cerebral perfusion pressure and arterial O2 saturation were controlled so that they produced no significant effect on the cerebral circulation. Other possible sources of error, e.g., blood temperature, effect of anesthesia, development of metabolic acidosis, and validity of internal jugular measurements of cerebral blood flow were evaluated. Arterial Pco2 was varied from 5 to 418 mm Hg in eight animals. The minimum and maximum cerebral blood flows obtained were 18 and 140 ml/min 100 g, respectively. These values were approached when the arterial Pco2 was in the range of 10–15 mm Hg and 150 mm Hg, respectively. At these levels of arterial Pco2 the maximum and minimum cerebrovascular resistance occurred. These values were 4.78 and 0.63 mm Hg/ml/min per 100 g, respectively. A mathematical analysis of the data enabled equations relating arterial Pco2 to cerebrovascular resistance and to cerebral blood flow to be derived. Values predicted by these equations compare favorably with the actual measured data and with similar data in the literature.
Oxygen consumption following exercise in the anesthetized dog
Authors: Kayne Herbert L. , Alpert Norman R.
Published: December 2017

Oxygen consumption and plasma lactate and pyruvate were measured in normal, eviscerated, eviscerated-hepatectomized, and eviscerated-hepatectomized-insulin-treated dogs before and after 5 min of mild exercise (direct tetanic stimulation of the muscles of the hind limbs.) The excess consumptions of oxygen during recovery were the same in all four groups; however, lactate and pyruvate removal were markedly impaired in the operated animals. This indicates a complete dissociation between oxygen consumption and metabolite removal during recovery from exercise.
Blood flow, blood oxygen tension, oxygen uptake, and oxygen transport in skeletal muscle
Authors: Stainsby Wendell N. , Otis Arthur B.
Published: December 2017

The effect of changes in blood flow and of blood oxygen tension on oxygen uptake of the in situ gastrocnemius-plantaris muscle group of the dog was examined. Oxygen uptake by resting muscle was not altered by changes in blood flow or blood oxygen tension except when these parameters were reduced below critical values. When the muscle group was contracting once per second, changes in blood oxygen tension were similarly without effect until a critically low value was reached. Although the contracting muscle used eight times as much oxygen per minute as resting muscle, the critical oxygen tension was lower than that for resting muscle. In an attempt to explain this observation the blood-tissue oxygen tension difference was estimated and used in the Krogh equation to calculate capillary density. The capillary density in contracting muscle was found to be much greater than in resting muscle and was about the same as the capillary density measured by others by histological techniques.
Influence of plasma bicarbonate concentration and pH on citrate excretion
Authors: Simpson David P.
Published: December 2017

Citrate excretion has been studied in dogs under various conditions of acid-base balance in order to determine which factors are responsible for the increased citrate clearance present in metabolic alkalosis. A close relationship, significantly modified by systemic pH, was found between plasma bicarbonate concentration and citrate clearance. In the presence of an alkaline plasma pH, there was a linear relationship between changes in plasma bicarbonate concentration and changes in citrate clearance. Other experiments also demonstrated the influence of plasma bicarbonate concentration on citrate clearance at alkaline pH. Under acidotic conditions citrate clearances were low and changes in plasma bicarbonate concentration had little effect on citrate excretion. A change in plasma pH from an acidotic to an alkalotic state, with a constant plasma bicarbonate concentration, produced an increase in citrate clearance. Thus the coexistence in metabolic alkalosis of high plasma bicarbonate concentration and high plasma pH results in a markedly increased citrate clearance.