bluuebunny/crossref_metadata_2025 huggingface dataset:
High-fidelity electrocardiograms of normal rabbits
Authors: Nelson C. V. , Waggoner W. C. , Gastonguay P. R.
Published: December 2017

Normal rabbit electrocardiograms were taken using high sensitivity, recording speed, and frequency response. The signals were recorded on magnetic tape and replayed with a time expansion of 32 to 1. Bipolar and augmented unipolar limb leads and two unipolar chest leads were recorded. Mean values, ranges, and standard deviations for the P, QRS, and T voltages were obtained, as well as mean frontal plane vectors. Similar data for durations were found. The ranges of mean axes were 44° to 86° for P, 55° to 103° for T, and –79° to +156° for QRS. The wide range in ventricular electrical axis may be due to changes in heart position. Notching of P and QRS complexes was due to the high resolution used.
Effect of Pitressin on lipolysis and on phosphorylase activity in rat adipose tissue
Authors: Vaughan Martha
Published: December 2017

Pitressin, a mixture of arginine and lysine vasopressins, stimulates the release of glycerol and of free fatty acids from rat epididymal fat pads in vitro. This effect is inhibited by prostaglandin E1, which has previously been shown to interfere with the analogous effects of catecholamines, ACTH, TSH, and glucagon. Like these latter hormones, Pitressin, added for a few minutes after tissues have been incubated in the absence of hormones, significantly increases the activity of phosphorylase and of the hormone-sensitive lipase. (The activity of both of these enzymes declines during the period of incubation before the hormone is added.) No effects of synthetic oxytocin at similar concentration on glycerol release or on phosphorylase activity were demonstrated.
Physiological disposition of C14-labeled rumen gases in sheep and goats
Authors: Dougherty R. W. , Allison M. J. , Mullenax C. H.
Published: December 2017

Transfer of radioactive carbon from rumen gases to blood, milk, and saliva was studied in sheep and goats following intraruminal insufflation of C14O2 and C14H4. In four sheep allowed to inspire eructated gas, radioactive carbon was detected in blood from the carotid artery 4–5 sec after the first rumen eructation contraction following C14O2 insufflation. In one sheep and one goat, which were not allowed to inhale eructated gas, there was eventual absorption of radioactive carbon from the digestive tract, but at a much lower level and without the marked fluctuations. In three sheep radioactivity gradually increased in the saliva samples until it was more than double that of blood samples collected simultaneously. In one lactating goat (two experiments) dissolved C14O2 appeared in milk within 3 min following the first eructation and reached maximum values within 15 min. Radioactivity was present in milk solids, primarily in the lactose fraction, 20 min after intraruminal insufflation of C14O2. In one sheep and two goats radioactivity in blood resulting from C14H4 insufflation was much less than after intraruminal insufflation of C14O2.
Renal vascular response to angiotensin and other vasoactive agents in endotoxin shock
Authors: Emerson Thomas E. , Brake Charles M. , Hinshaw Lerner B.
Published: December 2017

Renal vascular responsiveness to angiotensin, epinephrine, norepinephrine, and histamine was investigated before and after endotoxin shock in 25 anesthetized dogs. Drugs were injected into the renal artery inflow tubing in constant-flow, isolated kidney preparations. Mean renal vascular responses were compared for both peak elevation of renal artery pressure (RAP) and area under the RAP curve. In situ kidney preparations in which angiotensin and norepinephrine were infused intravenously after endotoxin were utilized in several experiments. Renal blood flow (RBF) and the dog's arterial blood pressure (ABP) were measured in both groups. Renal vascular responsiveness to angiotensin was virtually abolished within 1 hr after endotoxin. The RAP elevation produced by epinephrine and the decreased RAP following histamine injections were not significantly altered. In the in situ kidney studies, angiotensin was initially effective in elevating ABP after endotoxin, but RBF was further depressed; by approximately 1 hr after endotoxin, angiotensin infusion was ineffective. Norepinephrine infusion maintained the animal's ABP at a normotensive level and did not seriously reduce RBF.
Ventilatory response to transient perfusion of carotid chemoreceptors
Authors: Fitzgerald Robert S. , Zajtchuk Joan Tracz , Penman Robert W. B. , Perkins John F.
Published: December 2017

Properties of carotid chemoreceptors were evaluated in anesthetized dogs by measuring transient change in breath-by-breath minute ventilation (Ve) produced by brief (15–60 sec) infusion into common carotid arteries of blood of known Po2, Pco2, and pH while stopping blood flow from below. Evidence is presented that the preparation permits studying behavior of carotid chemoreceptors alone, no response to infusion of hypercapnic blood occurring after carotid body denervation. The carotid bodies reacted to infusion of hypercapnic blood as promptly as to cyanide, and responded significantly to increments in Pco2 of only 2 mm Hg. Ventilatory response curves to increments in Pco2 were obtained. Approximate magnitude of carotid chemoreceptor drive was evaluated by infusion of hyperoxic, hypocapnic blood (Po2 > 500, Pco2 < 10 mm Hg) which did not reduce Ve during O2 breathing, reduced it 24% during air breathing, and from 62 to 100% (apnea) during hypoxia.
Innervation of cat iris dilator
Authors: Schaeppi U. , Koella W. P.
Published: December 2017

Isometric tension changes of radially oriented iris strips of the cat were investigated in vitro. Electrical stimulation, norepinephrine (NE), and tyramine elicited contraction whereas isoproterenol elicited relaxation. Phentolamine reduced electrically and NE induced contractions and, in large doses, converted them to relaxation. Dichloroisoproterenol decreased this relaxation and the relaxation induced by isoproterenol. After chronic sympathetic denervation, electrical stimuli induced mainly relaxation and tyramine had no effect. These results indicate that contractions and relaxations in normal preparations are preponderantly mediated via excitation of adrenergic nerve terminals and release of adrenergic transmitter acting upon alpha and beta adrenergic receptors, respectively. Neostigmine and atropine had little effect on the electrically induced effects of normal preparations. In chronically denervated dilator strips, neostigmine increased and atropine decreased the relaxations and occasional slight contractions produced by electrical stimuli. These observations are interpreted that cholinergic relaxation mechanisms are also involved in the control of the dilator muscle, and that cholinergic contractions are due to activation of aberrant sphincter fibers contaminating the dilator muscle.
Adrenergic mechanisms in rabbit olfactory bulb
Authors: Salmoiraghi G. C. , Bloom F. E. , Costa E.
Published: December 2017

Antidromic stimulation of mitral cell axons in the lateral olfactory tract (LOT) produces inhibition of mitral cells in the ipsilateral olfactory bulb, presumably through activation of recurrent axon collaterals. In decerebrate rabbits, electrophoretic administration of norepinephrine (NE), acetylcholine (ACh), or serotonin (5-HT) to individual mitral cells decreases their discharge rate. By means of electrophoretic administration of known antagonists of ACh, NE, and 5-HT as well as of intravenous administration of drugs that deplete brain stores of NE, 5-HT, and dopamine, evidence was obtained favoring a close functional correlation between NE or a related substance and the LOT inhibitory response.
Collateral circulation after coronary artery constriction
Authors: Levy Matthew N. , Chansky Moris
Published: December 2017

The extent and distribution of the collateral circulation to the ventricular myocardium which develops after partial constriction of the left circumflex coronary artery for 1 week were investigated by means of the Rb86-clearance technic. Interarterial communications were distinguished from anastomoses occurring at lower levels of the vascular tree by comparing the Rb86 clearances obtained while the retrograde-flow tubing was clamped with clearances obtained while the tubing was patent. In the central region of the ischemic myocardium, there was a two- to threefold increase in the total collateral flow after coronary artery narrowing. The collateral vessels to this region were predominantly interarterial communications. The data suggested, however, that non-interarterial anastomoses to the central zones must also have proliferated. In the marginal zones of the ischemic region, the predominant communications were non-interarterial.
Activation of rabbit plasminogen by streptokinase
Authors: Chattopadhyay Dhurjati P. , Cliffton Eugene E.
Published: December 2017

When streptokinase was injected into whole rabbits the fibrinolytic and proteolytic activity of the plasma increased and antifibrinolytic and antiproteolytic activity and fibrinogen level fell. In vitro treatment of rabbit plasma with streptokinase produced strong fibrinolytic activity, but proteolytic activity was not observed unless trace amounts of human plasma were added. However, the euglobulin fraction of rabbit plasma also became proteolytic after streptokinase had been added to the system. A trace amount of human plasma was required for complete activation of rabbit plasminogen by streptokinase. Addition of rabbit plasma to streptokinase-bovine euglobulin mixture produced a strong fibrinolytic activity but failed to produce any proteolytic activity. This indicates the presence of proactivator in rabbit plasma. Rabbit plasma and the euglobulin supernatant fraction contain an inhibitor of proteolytic activity.
Localization of phosphaturic effect of parathyroid hormone in nephron of the dog
Authors: Samiy A. H. , Hirsch Philip F. , Ramsay A. G.
Published: December 2017

The renal mechanism and tubular site of the phosphaturic action of parathyroid hormone were investigated by clearance and stop-flow techniques in one intact and seven thyroparathyroidectomized dogs. Administration of hormone caused a significant increase in the excretion of phosphate without increasing the filtered load. Stop-flow analysis indicated that in the absence of parathyroid hormone most of the filtered phosphate was reabsorbed in the proximal tubule, and that the hormone increased the rate of phosphate excretion by inhibiting this reabsorptive mechanism. P32 injected during stopped flow showed no significant transport across the renal tubule despite the presence of excess parathyroid hormone. Significant P32 activity appeared in the stop-flow collections simultaneously with the appearance of new filtrate. There was no evidence that parathyroid hormone mediated a secretory process for phosphate excretion.
Kinetic characterization of the terminal vascular bed during inflammation
Authors: Aschheim Emil
Published: December 2017

A mixture of small- and large-molecular weight substances (Rb86 and albumin-I131) was injected intravenously into anesthetized rats at measured times after the topical application of a phlogogen. Blood and skin specimens obtained I min later were analyzed for their isotope content. It was found that at every stage of the inflammatory reaction studied the skin uptake of radioalbumin was linearly related to the uptake of Rb86. This relationship was positive and, in contrast to the normal skin, statistically significant. The various parameters of the regression equations are interpreted in terms of nutritional blood flow, intravascular plasma content, rate of plasma extravasation, and fractional blood-tissue clearance of albumin. These parameters are shown to change in a characteristic manner with the progress of inflammation.
Induction of milk secretion in the rabbit by removal of the telencephalon
Authors: Beyer Carlos , Mena Flavio
Published: December 2017

Extirpation of the telencephalon resulted in mammary growth and milk secretion in intact and in ovariectomized estrogen-primed rabbits. These effects were apparent within I week after the operation. More restricted lesions in the neocortex and olfactory bulbs did not induce these changes. From these results it is suggested that removal of the telencephalon causes release of prolactin and possibly ACTH from the adenohypophysis.
Experimentally induced variations in canine gastric blood flow and its distribution
Authors: Delaney John P. , Grim Eugene
Published: December 2017

Total gastric blood flow and its distribution between antrum and corpus, and to the mucosa, submucosa, and muscularis of the corpus were measured in dogs under the influence of several agents known to affect gastric secretion. Histamine, infused intravenously or administered chronically in beeswax intramuscularly, produced increases in cardiac output, the fraction of the output going to the stomach and, hence, gastric tissue perfusion Epinephrine infusions also caused significant increases in cardiac output and gastric perfusion. Norepinephrine was the only agent that raised gastric vascular resistance; despite an increase in cardiac output, blood flow to the stomach fell. Neither intravenous secretin nor inspired 10% CO2 affected gastric perfusion. All agents except histamine increased the antrum/corpus perfusion ratio. Only norepinephrine altered the distribution of flow to the several tissues of the corpus; it caused a shift of flow from mucosa to muscle. The results provide no support for the frequently stated conclusion that gastric blood flow and secretion are closely related.
Combined effects of nitrate and caffeine on contractions of skeletal muscles
Authors: Brust Manfred
Published: December 2017

Joint action of 1 mm caffeine and NO3– after exposure to NO3– alone did not increase tension output of excised, curarized gastrocnemius muscles of healthy mice beyond NO3– values. In dystrophic mouse muscles, twitch tension increased further and 1.5 times as much as in 1 mm caffeine alone. In both muscles caffeine pretreatment permitted NO3– further to enhance twitch tension as though it were acting alone. Caffeine enhancement of tetanus tension disappeared in normal and rose further in dystrophic muscles. In both muscles jointly evoked maximal twitch tensions were the same regardless of pretreatment. Neither agent alone could duplicate jointly elicited tension increases. In excised, curarized frog sartorius muscles jointly produced twitch tensions after NO3– pretreatment were the sum of individual NO3– and caffeine enhancements. Caffeine pretreatment reduced the subsequent NO3– alone. These results suggest defects in NO3–-susceptible Ca++ sites of dystrophic membranes, and greater sensitivity to caffeine-induced Ca++ mobility in frog than in mouse muscles.
Intrinsic innervation of the heart
Authors: Napolitano Leonard M. , Willman Vallee L. , Hanlon C. Rollins , Cooper Theodore
Published: December 2017

Electron microscopy of the normal canine heart reveals neural elements in the intercellular spaces of the atria and ventricles, including the papillary muscles. These neural elements are C fibers containing vesicles and electron dense granules. After total extrinsic cardiac denervation some C fibers remain in the atria and ventricles. These must arise from ganglion cells within the heart, and are thus by definition intrinsic and postganglionic. Whether the activity of such nerve fibers is related to adrenergic, cholinergic, or other neurohumoral substances is uncertain.
Variability of the anticoagulant fraction of incubated fibrinogen
Authors: Triantaphyllopoulos E. , Triantaphyllopoulos D. C.
Published: December 2017

The spontaneous breakdown of human fibrinogen or the lysis of Laki's fibrinogen by purified human fibrinolysin and streptokinase involves at least two different reactions. Clottability by thrombin and precipitability at 25% ammonium sulfate saturation are gradually lost but although clottability disappears completely at a fairly early stage, precipitability is still retained by 4–12% of the original protein even during advanced stages. Both the amount and the antithrombic activity of the anticoagulant fraction of incubated fibrinogen (AFIF) produced vary throughout fibrinogenolysis. The changing quality of AFIF is further evidenced by changes in the electrophoretic patterns which indicate variations in concentration, mobility, and number of components. Strip electrophoresis of fractions isolated by continuous-flow paper electrophoresis showed the presence of two components in the largest fraction but only of a single one of different mobility in a second, smaller fraction. The last finding makes it unlikely that the antithrombic effect exerted by the latter fraction could be due to contamination by components of the former.
Early increase of plasma potassium in hyperventilation
Authors: Blesa Enrique S. , González Norberto C. , Cingolani Horacio E.
Published: December 2017

Plasma potassium concentration was determined in arterial and in portal, hepatic, and peripheral venous blood during acute respiratory alkalemia. It was found that passive hyperventilation produces an increase in plasma potassium, reaching peak values after 15 min. The hyperkalemia is due to potassium release in the prehepatic splanchnic territory. The liver apparently plays no part in producing it, while muscular territories take up potassium.
Urea and inulin clearances in undisturbed, unanesthetized rats
Authors: Kleinman Leonard I. , Radford Edward P. , Torelli Giorgio
Published: December 2017

Inulin and urea clearances were determined simultaneously on unanesthetized, undisturbed rats with catheters permanently inserted in the abdominal aorta, jugular vein, and urinary bladder. The rats were fed a) a normal Purina chow diet; b) a high-protein diet with normal salt content; or c) a high-protein diet with 2% NaCl added. Some rats on the high-protein, high-salt diet were given additional infusions of either urea or 5% amino acid solution. In the control animals, inulin clearances averaged 0.59 ml/min per 100 g body wt, and urea clearances averaged 0.39 ml/min per 100 g body wt. Significantly higher urea and inulin clearances were obtained on the other diets. Of 79 clearances determined on normal rats given the high-protein, high-salt diet, a total of 17 urea-to-inulin clearance ratios greater than one were obtained No urea-to-inulin clearance ratios greater than one were obtained with any of the other diets. Reasons are given in support of urea production or active secretion by the kidneys as the probable explanations for these results.
Influence of inorganic electrolytes and ouabain on uric acid transport
Authors: Berndt W. O. , Beechwood E. C.
Published: December 2017

The importance of certain inorganic electrolytes in the transport of some organic acids by the kidney has been demonstrated. The present study was undertaken to evaluate further the transport characteristics for uric acid. Slices of rabbit kidney cortex were found to accumulate urate with a dependency on the medium potassium concentration. At 5 mm potassium the urate uptake was about 50% of maximum, with optimal accumulation above 10–40 mm potassium. Rubidium or cesium were found to substitute successfully for potassium; both substances permitted better uric acid accumulation than did potassium. Removal of sodium from the medium to concentrations as low as 65 mm did not influence urate uptake. At 15 mm sodium the urate accumulation was markedly depressed. Ouabain was found to depress urate uptake. The inhibition produced by this substance could be reversed by elevation of the medium potassium. Stop-flow analysis on the rabbit indicated that ouabain increased the proximal secretory peak for uric acid. On the basis of experiments where ouabain and probenecid were administered together, it was possible to attribute the action of ouabain to blockade of urate reabsorption.
Phase portraits of normal mouse muscle-fiber action potentials in high calcium
Authors: Evans Titus C. , Schottelius Byron A.
Published: December 2017

Action potentials were obtained from normal mouse soleus fibers immersed in high-calcium Ringer solutions and were recorded on a dual-beam oscilloscope as simultaneous voltage-time and phase-portrait plots. High calcium produced alterations resembling those noted in action potentials from mice with muscular dystrophy. Additional changes due to altered sodium activation and potassium activation were also present; since they occurred after the dystrophic-like alterations during the action potential and were not present in dystrophic mouse fiber records, it was concluded that a delayed potassium activation and current could not be responsible for the dystrophic-like changes. The data support a previously proposed hypothesis that dystrophic muscles have an increased secondary sodium influx during activity.
Rate of the reaction of carbon dioxide with human red blood cells
Authors: Constantine H. P. , Craw Margot R. , Forster R. E.
Published: December 2017

A CO2 electrode was adapted for use in a continuous-flow rapid-reaction apparatus to measure the kinetics of the hydration-dehydration reactions of CO2. The dehydration constant of the reaction was found to be 80 sec–1 at 37 C. Red blood cell suspensions were mixed with bicarbonate solutions to alter suddenly the Pco2 around the cells from 42 to 57, and from 3 to 37 mm Hg. The velocity constants for the hydration of CO2 inside the cell were 236 and 772 sec–1, respectively, as compared with the uncatalyzed rate of 0.11 sec–1. These uninhibited rates are 0.16 and 0.54 the potential catalyzed rate in the cell, suggesting that some other process is rate limiting. In the presence of 0.25 g/liter acetazolamide, the velocity constants decreased to 28 and 65 sec–1, respectively.
Inorganic phosphate and Na+ increases in liver after partial hepatectomy
Authors: Lieberman Irving , Gingold James L. , Kane Patricia , Short John
Published: December 2017

After removal of two-thirds of the liver, no changes occur in the hepatic content of K+, Ca++, Mn++, but liver P1 and Na+ rise. The increase in P1 (20–30%) is more than half maximal 5 min after the operation, and with Na+ (about 30%) the rise is complete at this time. These increases appear to represent intracellular rather than extracellular changes. They are related to the amount of liver removed and, judging by the inability of puromycin to affect the ion rises, they are not dependent on prior protein synthesis. Permanent ligation and ligation for 10 min of the portal branch to the 67% portion of the liver causes an early increase in the P1 content of the 33% part of the liver, but the Na+ rise occurs only after a delay of about 4.5 hr. Neither the P1 nor the Na+ rise appears to be causally related to the changes in hepatic RNA synthesis and nuclear electrophoretic mobility that result from partial hepatectomy or ligation of the portal branch vessel.
Relationship of pNH3 of tubular cells to renal production of ammonia
Authors: Pilkington Lou Ann , Welch John , Pitts Robert F.
Published: December 2017

Renal excretion of ammonia, addition of ammonia to renal venous blood, and total renal production of ammonia were measured in acidotic dogs before and during the intravenous infusion of ammonium chloride at rates of 0.5 and 1.0 mmole/min. Infusion of ammonium chloride increased urinary excretion of ammonia, reversed the direction of diffusion of ammonia between tubular cells and blood, i.e., induced the extraction of ammonia from blood, and reduced cellular production of ammonia. Production of ammonia was an inverse function of pNH3 of tubular cells. The infusion of ammonium lactate-N15 into one renal artery increased total ammonia excretion but decreased production of ammonia-N14 from normal blood-borne precursors. The intravenous infusion of ammonium chloride reduced extraction of glutamine from renal blood, yet increased the concentration of free glutamine in renal cortical cells. Our data suggest that an increase in pNH3 of tubular cells results in competitive inhibition of the glutaminase-1 reaction. We further suggest that the pNH3 of tubular cells is one factor governing renal production of ammonia; i e., the higher the cellular pNH3, the lower is the renal production of ammonia.
Erythropoietin in vitro. III. Perfusion of a lung-kidney preparation
Authors: Erslev Allan J. , Solit Robert W. , Camishion Rudolph C. , Amsel Sheldon , Ilda Junzo , Ballinger Walter F.
Published: December 2017

A critical review of six studies of perfused kidneys suggests that the methods used do not quite justify the common conclusion that an isolated kidney is capable of generating erythropoietin in response to hypoxia. In a repeat study, the gas tensions and pH were adjusted carefully in a perfused isolated dog lung-kidney preparation and the erythropoietin assays were carried out on standardized polycythemic rats or mice. In all of 13 technically successful experiments no generation of erythropoietic material could be demonstrated after 4 hr of perfusion with normal, hypoxic, or anemic blood. This unexpected result is discussed and it is suggested that erythropoietic material is released only from injured and disintegrating renal tissue but not from well-preserved and metabolically active kidneys.
Nitrate, thiocyanate, and perchlorate clearance in relation to chloride clearance
Authors: Walser MacKenzie , Rahill W. Joseph
Published: December 2017

Simultaneous clearances of inulin, chloride, and nitrate, thiocyanate, or perchlorate were measured in salt-depleted dogs and/or dogs undergoing diuresis induced by mannitol, saline, or sulfate. A method for perchlorate determination in body fluids using methylene blue is given. Plots of excreted/filtered NO3, SCN, or ClO4 against excreted/filtered Cl were made for the present data and for data taken from the literature. All of the available nitrate data conform to a power function between these two variables with an exponent of .36–.38. Thiocyanate clearance was nearly equal to chloride clearance; during infusion of other foreign anions it was usually higher than chloride clearance. Perchlorate clearance was much higher than chloride clearance but varied with it. It is concluded that all of these anions may be reabsorbed passively and noncompetitively in the same portions of the nephron; distal active reabsorption may also play a role.
Effect of hypoxemia and hypercapnia on regional distribution of myocardial blood flow
Authors: Love William D. , Tyler Myra D.
Published: December 2017

The effect of hypoxia and hypercapnia on regional coronary blood flow and vascular resistance (CVR) was studied in dogs without thoracotomy. Gas tensions were varied by ventilation at controlled rates with gas mixtures containing 4–100% O2 and 0–24% CO2. After 10 min intravenous infusion of Rb86, the animals were killed and the heart isotope content determined. Blood flow to the left ventricle was calculated by the Fick principle from the isotope uptake and the mean difference in radioactivity of arterial and coronary sinus blood. Patterns of flow elsewhere were estimated from the rates of regional Rb86 clearance. Myocardial Rb86 clearance in the right and left ventricles has been previously shown to be closely related to the rate of coronary blood flow. Hypoxemia and severe hypercapnia (pCO2 above 100 mm Hg) both produced a profound fall in CVR. With hypoxemia this decrease was more marked in the right ventricle. Elevation of pCO2 exaggerated the normal difference in Rb86 uptake between inner and outer thirds of the wall of the left ventricle, while hypoxemia reversed the normal gradients. Hypercapnia did not affect these gradients in the right ventricle, but hypoxemia significantly reduced them.
Effect of acetazolamide on gastric mucosa in canine vivo-vitro preparations
Authors: Werther J. Lawrence , Hollander Franklin , Altamirano Mario
Published: December 2017

Segments of canine gastric fundus with intact blood supply were studied in acute experiments using the chamber preparation of Altamirano et al. Solutions of varying acidity were placed in the chamber in contact with the mucosal surface, and the effect of intravenous acetazolamide observed and compared with controls. Acetazolamide resulted in gross and microscopic damage to the surface mucosa in both secreting and nonsecreting preparations, provided the mucosal bathing solution had an acidity of 30 mEq/liter or greater. The apparent inhibition of acid secretion after acetazolamide was greater when mucosal bathing solutions of 160 mEq/liter of HCl were used than with solutions of lesser acidity. This relationship appears to result from the acceleration of H+ loss from the luminal fluid through the surface mucosa following acetazolamide. These effects of acetazolamide are not dependent on the presence of acid secretion per se, and occur in preparations in which acid secretion was not detected as well as in those actively secreting acid in response to histamine administration.
Bile salt absorption in the irradiated rat
Authors: Sullivan Maurice F.
Published: December 2017

Measurements of radioactivity in bile secreted by bile duct-cannulated rats after intraluminal injection of the labeled bile salt indicated bile salt absorption rates in the duodenum, ileum, and large intestine in the ratio of 1:30:2. Three days after exposure of the abdomen to 1,000 or 1,500 R of X-irradiation, absorption from the ileum was decreased by 14 and 53%, respectively. Five days after exposure to 1,500 R, absorption from the ileum was decreased by 70%. The radiomimetic nitrogen mustard, HN2, also decreased absorption. This was shown to be a radiation-induced absorption defect which probably resulted in increased excretion of bile salts, rather than an impaired secretion of bile by the liver, by injecting labeled bile salts intravenously or parenterally. At 4 days after 1,500 R and 1 day after intravenous injection of C14-labeled cholic acid, the accumulation of labeled bile salt in the lower bowel was almost twice the unirradiated value. The level of radioactivity secreted in the bile at that time was one-half control value and that present in the small intestine only one-sixth the unirradiated level, suggesting a dilution of the labeled bile salt as a result of de novo synthesis and a substantial accumulation of bile salts in the lower small intestine and large bowel.
Tracer microinjection studies of effect of ADH on renal tubular diffusion of water
Authors: Morel François , Mylle Margaret , Gottschalk Carl W.
Published: December 2017

The tracer microinjection technique was utilized to study the effect of vasopressin (ADH) on transtubular water diffusion in rats with diabetes insipidus. Inulin-C14 and tritiated water (HTO) were simultaneously injected into the same distal convolutions before and after intravenous administration of ADH, and their recovery in the urine of the injected kidney measured. Urine flow was maintained constant by intravenous infusion of mannitol. ADH had no effect on inulin recovery, but delayed and reduced HTO excretion. Total HTO recovery averaged 19% before and 11% after ADH, and direct HTO recovery averaged 8% before and 1% afterward. A theoretical treatment of the data is presented which leads to the conclusion that ADH increases the permeability to water diffusion of the luminal surface of the cellular membranes of the distal convolutions and/or collecting ducts, but has no effect on permeability to water diffusion of their basal surfaces.
Renal excretion of ascorbic acid by dogs
Authors: Kleit Stuart , Levin Daniel , Perenich Theresa , Cade Robert
Published: December 2017

The renal excretion of ascorbic acid was evaluated in dogs by clearance experiments and stop-flow analyses. After stimulation of the distal sodium-potassium exchange mechanism with deoxycorticosterone acetate, clearance experiments revealed ascorbic acid-to-creatinine clearance ratios as high as 1.54. Stop-flow analyses revealed a distal secretory peak in the area of sodium-potassium exchange with U/P-to-U/P ratios as high as 1.3. These experiments demonstrate that secretion of ascorbic acid occurs in the distal tubule. Linkage with the distal sodium-potassium exchange and an effect of urine pH on tubular handling of ascorbic acid are postulated.
Release of vasopressin from isolated guinea pig posterior pituitaries
Authors: Haller E. W. , Sachs H. , Sperelakis N. , Share L.
Published: December 2017

Isolated guinea pig posterior pituitaries, incubated in a modified Krebs-Ringer solution at 37 C, released vasopressin at a relatively constant basal rate. Electrical stimulation at a voltage gradient of 3–9 v/cm (200-msec pulses of 60 cycles/sec ac every 2 sec) resulted in an elevation of vasopressin output. Stimulation at lower field strengths was not effective and maximal vasopressin release was produced by stimulation at any voltage gradient between 3 and 9 v/cm. Vasopressin secretion was augmented at rest and during electrical stimulation by the presence of 2 mm Ba++ in the incubation medium (increase of Ca++ by 2 mm had no effect). Tetracaine (0.5 mm) blocked the response to electrical stimulation. Chemical, biological, and enzymic tests indicated that the pressor material secreted by the tissue was identical with arginine vasopressin. The experimental findings support the hypothesis that conduction of action potentials along the hypothalamo-neurohypophysial tract releases vasopressin from the posterior pituitary.
Ammonium excretion during stopped flow: a hypothetical ammonium countercurrent system
Authors: Sullivan Lawrence P.
Published: December 2017

Successive ureteral occlusions were performed on chronically acidotic animals infused first with HCl and then with NaHCO3. Peak ammonium concentrations developed in very distal samples of each occlusion were compared with urine pH. In successive occlusions on any one dog, the line relating peak ammonium concentration to urine pH closely followed the slope predicted by the theory of nonionic diffusion when urine pH was above 6.0. When urine pH was below 6.0 in successive occlusions, the slope was significantly less than the theoretical. In these latter experiments, doubling occlusion time resulted in small increases in ammonium concentration. Glutamine infusions raised ammonium concentrations and tended to shift the slope towards the theoretical at urine pH's down to 5.6. In alkalotic animals, the ratio [NH4]u/ [NH4]b was much greater than predicted by theory, and urine concentrations of the free base NH3 were as much as fourfold greater than renal venous blood concentrations. A counter-current mechanism for ammonium is proposed to explain the ability of the kidney to concentrate NH3 in alkaline urine.
Skeletal marrow volume in dog
Authors: Gong Joseph K. , Arnold J. S.
Published: December 2017

A method for determining dog marrow volume was described. The skeletal bone was considered to be of three parts: trabecular and cortical bones and marrow, all containing water and nonfatty organic material. Fat and mineral fractions were considered to be exclusively of the marrow and bones, respectively. The marrow water and nonfatty organic fraction (each obtained by taking the difference in its amounts found in the trabecular plus cortical and skeletal bones) and all of the fat equals the marrow volume. The vertebrae were the major contributors to the total marrow, containing half of the over-all marrow water and nonfatty organic fractions. The long bones contained most of the fat. A large amount of fat was also found in the vertebrae, skull, and the pelvic girdle. The marrow content in individual skeletal bones ranged from 23.9% for the mandibles to 65.9% for the sternum. About 49% of the skeleton was marrow.
Blockage of epinephrine-induced hyperglycemia during exposure to simulated altitudes
Authors: Ui Michio
Published: December 2017

Hyperglycemia elicited by subcutaneous injection of epinephrine (10 µg/rat) was completely abolished during the exposure of the rat to a simulated high altitude (220–250 mm Hg). Addition of 5–7% CO2 to the inspired gas during the altitude stress restored the hyperglycemic activity of epinephrine, suggesting that the alkalosis or hypocapnia provoked by hyperventilation, but not hypoxia itself, would be involved in the prevention of the hyperglycemic action of epinephrine. Glucose tolerance tests and in vitro experiments using isolated rat diaphragm showed that the inhibitory action of epinephrine on peripheral glucose utilization was abolished by shifting the pH of body fluids or incubation media toward higher levels. It was concluded that alkalosis, either directly or indirectly, abolished the hyperglycemic action of epinephrine as a consequence of the release of the inhibitory action of epinephrine on muscle glucose utilization.
Effects of denervation on normal and dystrophic muscle: DNA and nucleotide enzymes
Authors: McCaman M. W. , McCaman R. E.
Published: December 2017

The activities of five enzymes associated with nucleotide metabolism, as well as values for protein and DNA-P, in homogenates from normal, dystrophic, and denervated (3–46 days) normal and dystrophic mouse gastrocnemii have been reported. When the data were expressed per muscle, the following observations were made: protein was much lower in dystrophic than in normal muscle and decreased in both muscles after denervation; DNA-P values remained relatively constant in normal muscle after denervation whereas the values in dystrophic muscle were slightly lower; adenylic deaminase activity decreased rapidly and profoundly after denervation of normal muscle, approaching values found in dystrophic muscle; purine nucleoside phosphorylase and 5-nucleotidase activities were similar in normal and dystrophic muscle and remained relatively constant after denervation; Ca- and Mg-ATPase activities were considerably lower in dystrophic muscle and decreased in both normal and dystrophic muscle after denervation. The different interpretations of the same data which are possible by expressing data per unit protein versus per muscle were discussed. These results confirm earlier studies which demonstrated the striking biochemical similarity between dystrophic and denervated muscle.
Heat production of tropical snakes in relation to body weight and body surface
Authors: Galvão Paulo Enéas , Tarasantchi Jacob , Guertzenstein Pedro
Published: December 2017

The heat production of 50 tropical adult snakes weighing from 11 to 21,900 g was determined by measuring the O2 consumption. The relation between heat production in gram-calories per hour ( C) to body weight in grams ( W) for all 50 snakes was found to be C = 0.34 W0.86 The equation for 16 Boidae (weighing from 920 to 21,950 g was C = 0.04 W1.09 and that for 34 Colubridae (weighing from 11 to 3,774 g) was C = 0.21 W0.98. Any of these equations shows that metabolism of tropical snakes is not proportional to body surface. The proportionality of heat production to the metabolically active weight is discussed. The results are confronted and discussed with those obtained by European and American authors who have found proportionality of metabolism of poikilotherms to body surface or to W0.67–0.75
Pharmacologic properties of antihistamines in relation to vascular reactivity
Authors: Altura Burton M. , Zweifach Benjamin W.
Published: December 2017

Experiments were designed to gain further insight into the vasoconstrictor action of antihistamines and to assess further the validity of using antihistamine constrictor action to implicate the presence of "intrinsic" histamine in the terminal vascular bed of normal animals. Experiments with adrenergic blockers eliminate endogenous epinephrine as the sole mechanism responsible for the observed vasoconstriction with antihistamines. Furthermore, experiments with antiserotonin compounds indicate that the constriction cannot be attributed to endogenous 5-HT. In addition, experiments with a cholinergic blocking agent as well as with a local anesthetic eliminate cholinergic or local anesthetic mechanisms as being responsible for the observed antihistamine constriction. The local action of antihistamines likewise clearly rules out a central nervous system pathway which might operate in animals given antihistamines systemically. Experiments with bilateral adrenalectomized animals reveal heightened antihistamine constrictor action which is greatly exacerbated when these animals are given Dibenzyline. These findings are discussed in relation to recent work with antihistamines on ion transport. The present study questions the use of antihistamine constrictor action, to validate the presence and contribution of intrinsic histamine in microcirculatory regulation of normal animals.
Absence of direct chronotropic action of angiotensin infused into the sinus node artery
Authors: James Thomas N.
Published: December 2017

Angiotensin was shown to have no significant direct chronotropic action when perfused into the canine sinus node through its artery in situ. A slight cardiac acceleration which occurs during the systemic effect (aortic hyper-tension) from angiotensin is not due to sensitization of the sinus node to norepinephrine. Since it can be reversed and blocked with naphthylisoproterenol, this sinus tachycardia is presumably mediated by catecholamines delivered to the heart from an extracardiac source. Slowing of the sinus node during hypertension from angiotensin in the nonatropinized dog is due to a vagal reflex and is not caused by a direct negative chronotropic effect on the sinus node.
Appearance of excess lactate in anesthetized dogs during anemic and hypoxic hypoxia
Authors: Cain Stephen M.
Published: December 2017

Ten anesthetized, splenectomized dogs were made progressively anemic by replacement of blood with warmed dextran to approximate hematocrits of 30, 20, 15, and 10%. A second group of 10 dogs was made progressively hypoxic by having them inspire 11.4, 9.5, 8.0, and 5.9% O2 in N2. Blood gas contents, pH, and gas tensions were measured in arterial and mixed venous bloods. Cardiac output was calculated from the arteriovenous O2 difference and the O2 uptake. Excess lactate was calculated from measured levels of lactate and pyruvate in blood water. Excess lactate appeared at higher mixed venous Po2 in anemic animals than in hypoxic, 40 mm Hg versus 20 mm Hg. When related to total oxygen transport, however, excess lactate appeared at about the same point (12 ml/kg per min) in both groups. Because liver has been shown to reduce its oxygen uptake with any lowering of perfusate oxygen content, it was suggested that the excess lactate measured during both anemic and hypoxic hypoxia in anesthetized dogs is largely the result of liver dysfunction with respect to lactate.
Cardiac output determinations by the dye-dilution method in Squalus acanthias
Authors: Murdaugh H. Victor , Robin Eugene D. , Millen J. Eugene , Drewry William F.
Published: December 2017

A dye-dilution technique has been adapted for the measurement of cardiac output in the elasmobranch, Squalus acanthias. Cardiac output averaged 1.60 ± 1.00 liter/kg per hr in 26 fish. Small fish showed a relatively high cardiac index (liters/kg per hr) as compared with large fish. The use of this technique permits sequential cardiac output measurements with the maintenance of an intact physiological status. This technique should permit quantitation of exchange of a variety of substances across the gill membranes.
Immunochemical detection of an acute-phase protein in rat serum
Authors: Weimer Henry E. , Benjamin David C.
Published: December 2017

A new protein designated α2-AP (acute phase) globulin, not present in normal rat serum, has been detected by immunochemical methods in a wide variety of pathologic states. The protein is a carbohydrate-containing euglobulin and migrates with the mobility of an α2-globulin in filter paper and agar gel. In acrylamide and starch gels it exhibits a very low mobility suggestive of a macroglobulin. It is not related antigenically to C-reactive protein or Cx-reactive protein. Possible factors responsible for the production of the protein were discussed. It was concluded that the appearance of the protein in the circulation represents a systemic manifestation of the acute inflammatory response, and that the synthesis of the protein is stimulated by substances released from injured or necrotic cells.
Composition of canine renal hilar lymph
Authors: Keyl M. J. , Scott J. B. , Dabney J. M. , Haddy F. J. , Harvey R. B. , Bell R. D. , Ginn H. E.
Published: December 2017

Lymph was collected from a vessel in the hilar region of the kidney in 33 dogs. Care was taken to leave other renal lymphatics undisturbed. Renal lymph and urine were collected continuously and arterial blood periodically. The renal lymph-to-arterial plasma ratios of all endogenous substances measured were essentially unity except urea, total protein, and calcium, whose ratios were less than one. Intravenously infused PAH and inulin appeared in renal lymph in concentrations of 58 and 80%, respectively, of their concentrations in arterial plasma. In five dogs, both hilar and capsular lymph was collected simultaneously. Sodium concentrations were similar in these samples and in neither was sodium more concentrated than in arterial plasma.
Changes in type of hemoglobin during experimental hemorrhagic anemias in sheep
Authors: Blunt M. H.
Published: December 2017

A new hemoglobin was produced in sheep with Hb A during experimental anemias. This hemoglobin, called Hb Aα, had different electrophoretic characteristics and denatured with alkali at a faster rate than normal Hb A. It also showed electrophoretic differences to Hb B and Hb F. Hb Aα was located almost entirely in the reticulocytes produced during the anemia. The reticulocytes produced in anemic sheep with Hb B contained a hemoglobin which showed only minor differences from the normal hemoglobin on electrophoresis. However, it denatured at a faster rate than the normal hemoglobin. It is postulated that Hb Aα is a relatively unfinished hemoglobin associated with the immature erythrocytes produced after a severe anemic stress. It did not appear to be fetal hemoglobin.
Effect of lactic acid on free fatty acids and glucose oxidation in dogs
Authors: Issekutz B. , Miller H. I. , Paul P. , Rodahl K.
Published: December 2017

Palmitate-1-C14 or glucose-C14(U) was infused intravenously for 4 hr at a constant rate in unanesthetized dogs with indwelling arterial and venous catheters. O2 uptake and CO2 output were measured. Specific activity of CO2 and of plasma FFA or plasma glucose was determined. Infusion of Na-l(+)-lactate greatly reduced the rate of release and uptake and the rate of oxidation of FFA in normal as well as in pancreatectomized dogs. Lactate decreased also the oxidation of plasma sugar but to a lesser degree. The elevated blood lactate seems to have a glucose-sparing effect in the resting dog. This may lead to accumulation of α-glycerophosphate and may explain the FFA-lowering effect of lactate. Na-d(–)-lactate infused in comparable concentration had no similar effect.
Periodicities in efferent discharge of splanchnic nerve of the cat
Authors: Cohen M. I. , Gootman P. M.
Published: December 2017

Page 1092: M. I. Cohen and P. M. Gootman. "Periodicities in efferent discharge of splanchnic nerve of the cat." Page 1099, column 1, line 5: references should read (27, 28, Fig. 7 in ref 45).