bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanism of histamine release in endotoxin shock
Authors: Hinshaw Lerner B. , Jordan Margaret M. , Vick James A.
Published: December 2017

Reports from this laboratory have dealt with hemodynamic changes after injection of endotoxin and the role of histamine in endotoxin shock. This study relates to the mechanism of histamine release. Anesthetized dogs were administered lethal doses of E. coli endotoxin. During the course of the subsequent hypotension, simultaneous increases of blood histamine, histamine-histidine ratio(H/Hd), and circulating hematocrit were observed. Results suggest that a conversion from histidine to histamine occurs at an accelerated rate following endotoxin administration. These findings give further evidence for the active role of histamine in endotoxin shock and support a hypothesis recently proposed by Schayer.
Interdependence of urea and electrolytes in production of a concentrated urine
Authors: Schmidt-Nielsen Bodil , O'Dell Roberta , Osaki Humio
Published: December 2017

In most mammals, ability to concentrate urea in the urine exceeds that for electrolytes; this was not found in beaver, pig, and the desert rodent Psammomys. When these animals were exposed to water deprivation, Pitressin administration, urea, and salt loading, the urine osmotic concentration was constant regardless of which solute dominated in the urine. When the urea concentration was high, total electrolyte concentration was low, and vice versa. In salt-loaded animals, urea and electrolyte concentrations in the papilla nearly equaled urea and total electrolyte concentrations in the urine. In urea-loaded animals, urea concentration in the papilla was markedly lower than in urine and electrolyte concentration was correspondingly higher, so that calculated osmolarity in the tissue still equaled the osmolarity in the urine. It is possible that the permeability of the collecting ducts to urea changes with the loading solute. This could explain the inverse relationship between the urea and electrolyte concentrations in the urine.
Short-circuit current measurements in proximal tubule of Necturus kidney
Authors: Eigler Friedrich Wilhelm
Published: December 2017

A modified short-circuit method, which requires only one pair of electrodes, was applied to the proximal tubule of the Necturus kidney for determination of the short-circuit current as a measure of active ion transport across the tubular wall. The indifferent electrode was placed on the surface of the exposed kidney and the tubular lumen was punctured with a microelectrode. After injection of oil into the glomerulus of the same nephron, a marked increase in electrical resistance between the electrodes during oil passage at the puncture site indicated the proper position of the electrode tip in the tubular lumen. The largest area effectively short-circuited (12.5 x 10–4 cm2) was determined by changing the position of two oil droplets between which measurements were made. Thirteen measurements of the short-circuit current in anesthetized normal Necturi averaged 4.8 x 10–6 amp/cm2, which corresponds to an active monovalent ion transport of 4.6 x 10–11 Eq/cm2 x sec.
Relationship of antral and fundic vagal denervation to gastric secretion
Authors: Oberhelman Harry A. , Johnson Alstrup N. , Dragstedt Lester R.
Published: December 2017

Vagus-denervated Heidenhain pouches were prepared in 11 dogs. After control observations were made, the effect was determined of vagal denervation of the antrum, followed by bilateral vagotomy, on the 24-hr output of gastric secretion, the response to histamine, and the response to a standard test meal. The effect of vagal denervation of the body and fundus of the stomach was studied in two additional dogs. Vagal denervation of the antrum produced a reduction in the 24-hr output of HCl, with a significant increase in secretion when followed by bilateral vagotomy. Fundic denervation produced a significant increase in secretion from the Heidenhain pouch. The results suggest that the denervated antrum is less responsive to stimuli than the innervated antrum; that antral denervation does not produce gastric stasis; that the increased secretion following vagotomy probably results from fundic denervation, rather than antral denervation; and that the increased secretory response to histamine following vagotomy suggests the presence of an antral inhibitory hormone.
Electrical activity of intestine recorded with pressure electrode
Authors: Bortoff Alex
Published: December 2017

The effects of certain autonomic and metabolic drugs on the electrical activity of the small intestine have been investigated, using the pressure electrode. Epinephrine inhibits spike activity and increases the membrane potential, without apparently altering the size of the slow waves. Acetylcholine has the reverse effect. The hyperpolarization produced by epinephrine is followed by a gradual depolarization which exceeds that of the membrane prior to its addition; this is not accompanied by the reappearance of spike activity. Large concentrations of epinephrine produce a waxing and waning of the amplitude of the slow waves. During inhibition by dinitrophenol, both acetylcholine and epinephrine can initiate slow wave activity. An explanation of naturally occurring waxing and waning is suggested, together with a mechanism relating the activity of the two muscle layers during normal intestinal motility.
Mitochondrial oxidative enzymes and phosphorylations in cold exposure and hibernation
Authors: Chaffee Rowand R. J. , Hoch Frederic L. , Lyman Charles P.
Published: December 2017

Oxidative enzyme activities and oxidative phosphorylations of the liver mitochondria of a hibernating species, the golden hamster, and a nonhibernating species, the albino Wistar rat, were examined for changes in response to prolonged cold exposure. Succinic and glutamic oxidase, succinic-triphenyltetrazolium reductase, and cytochrome oxidase activities were measured. The mitochondria from cold-exposed rats showed no major changes (except for a high succinic-triphenyltetrazolium reductase activity), and normal P:O ratios (moles of phosphate esterified per gram atom O2 consumed). In both active and hibernating cold-exposed hamsters, all oxidative enzymes measured at 37 C were increased in activity, and the P:O ratios were normal. The mitochondria of hibernators contain a temperature-sensitive succinic oxidase system; when measured at 7 C, this activity is lower in the hibernators than in active cold-exposed animals or control animals. On the basis of the criteria used here hibernation does not involve a loss of oxidative capacity.
Regulation of plasma free fatty acid turnover
Authors: Armstrong D. T. , Steele R. , Altszuler N. , Dunn A. , Bishop J. S. , De Bodo R. C.
Published: December 2017

Plasma free fatty acid (FFA) turnover rates have been estimated in dogs by a technique involving measurement of FFA specific activities during constant intravenous infusion of trace amounts of C14-labeled palmitic acid. In order to determine the relationship between FFA concentration and turnover, variations in plasma FFA levels ranging from 0.081 to 3.31 µEq/ml were induced by a variety of physiological and pharmacological treatments. Calculated FFA turnover rates ranged from 2.1 to 58.8 µEq/kg/min, with a highly significant linear regression of FFA turnover on FFA level. It is concluded that under a variety of conditions changes in FFA concentration are brought about by changes in FFA production rate and that changes in FFA uptake are simple mass-action effects of changes in FFA concentration. Respiratory C14O2 data are presented indicating that about one-fourth of the total expired CO2 is derived from FFA in the postabsorptive state. This accounts for the immediate fate of about one-fourth of the total FFA leaving the plasma.
Physiological disposition of D- and l-triiodothyronine in rats
Authors: Hatfield W. B. , Ross J. E. , Herz R. , Tapley D. F.
Published: December 2017

The physiological disposition in the rat of d- and l-triiodothyronine has been compared. Following intravenous injection, the two isomers were removed from the circulation at similar rates but were taken up by different tissues. d-Triiodothyronine was concentrated in the liver and kidney to a greater extent than the l-isomer. On the other hand, higher concentrations of l-triiodothyronine were found in all other tissues, especially brain and muscle. With the d-isomer, a greater fraction of the radioactivity was excreted in the urine, presumably as the result of a more rapid deiodination. As in previous studies with thyroid hormones, the disposition observed seemed to correlate well with the known functions of the two isomers in vivo. The results emphasize how meaningless is the calculation of a "space" or "volume of distribution" of any particular compound on the basis of blood levels alone.
Competitive inhibition of renal transport of p-aminohippurate by analogues of chlorothiazide
Authors: Essig Alvin
Published: December 2017

Competitive inhibition of p-aminohippurate (PAH) transport by analogues of chlorothiazide has been demonstrated with slices of rabbit kidney cortex. Although analogues of low pK1 are better inhibitors of PAH transport than are analogues of higher pK1, no clear dependence of inhibitory capacity on degree of ionization at physiological values of pH was demonstrable. In contrast to earlier findings with phenolsulfonphthaleins and m- and p-substituted hippurates, no relation was noted between rate of transport and molecular weight or capacity to inhibit PAH transport. Similarly, no relation was noted between rate of transport and pK1. None of the analogues affected potassium content or uptake of K42.
Physiological effects of deuterium on dogs
Authors: Czajka Dorice M. , Finkel Asher J. , Fischer Conrad S. , Katz Joseph J.
Published: December 2017

The physiological consequences of the deuterium isotope effect in large mammals were studied in two dogs, one of which was maintained at 20% concentration of D2O in the body fluids for 50 days, and the other at the toxic range of 33–35% for a brief period. Deuteration of the dogs was effected by replacement of ordinary water with deuterium oxide in both food and drink. Hemoglobin, hematocrit, and red blood cell count dropped but the white blood cell count was essentially unaffected although there was a progressive lymphopenia and granulocytosis. Serum glucose was decreased, especially at higher deuterium levels. Total serum cholesterol values were also diminished although the esters were essentially unchanged. Serum sodium and both NPN and BUN were within normal limits except for a terminal elevation of the latter. Serum potassium was slightly lowered for a brief period after 3 weeks. Electrocardiograms showed ST segment coving and elevation and an increase in the QT ratio that suggested nonspecific myocardial damage; these changes reverted to normal while the dog was still deuterated at a level of 20%. Both dogs exhibited neuromuscular disturbances, in one case definite weakness of the hind legs and in the other, fine muscle tremors.
Granulocyte release by endotoxin in normal and irradiated mice
Authors: Smith Willie W. , Alderman Ilo M. , Cornfield Jerome
Published: December 2017

Granulocyte mobilization brought about by S. typhosa endotoxin was studied in normal and irradiated mice in which initial counts ranged from 100 to 5,000/mm3 in tail blood and 100 to 1,800/ mm3 in orbital sinus blood. In irradiated mice, 4–11 days after exposure, late occurrence of granulocytosis and absence of a peak at beginning of mobilization are presumably related to marrow aplasia. A transitory increase in percentage of young forms and a thinning of cellular population density in femoral marrow indicates an early contribution from this source. Although counts from tail blood during peak mobilization were extremely high compared to counts from orbital sinus blood, a few hours later mobilization ratios in both tail and sinus blood were the same for irradiated and nonirradiated mice, without regard to initial count. (Mobilization ratios were about twice as high in tail blood as in sinus blood.) A multicompartment system is proposed which is compatible with constant mobilization ratios. Under this model, when rate of delivery from marrow is slow relative to rates of transfer between compartments, ratios of compartment sizes become a constant independent of time and initial conditions and dependent only on magnitude of rate constants.
Secretion of calcium and phosphate by the dog parotid gland
Authors: Langley L. L. , Grimes O. R. , Cockrell D. F.
Published: December 2017

In dog parotid saliva, calcium is two to three times more concentrated than it is in the plasma. Phosphate in the saliva is less than one-fifth that of the plasma. Increasing the plasma phosphate level by a factor of 7 increases the saliva phosphate only twice. Salivary calcium varies almost proportionately with plasma calcium. After parotid secretion begins, the concentrations of both calcium and phosphate progressively decrease until a steady state is reached. Calcium and phosphate concentrations increase slightly in the saliva as the secretion rate decreases. At very slow rates there is a more marked increase. During the stop-flow procedure both calcium and phosphate concentrations increase, but to a strikingly different degree and at different sites in the gland. The increase in phosphate is almost exclusively the organic fraction. It is concluded that water and electrolytes are transferred from plasma to saliva by processes that are not coupled, and that proceed at varying and independent rates. The site of these transfers is distal, probably at the level of the ducts.
Disappearance of depot fat in rats fed extremely hydrogenated oils
Authors: Horst Antoni , Kaganowicz Izydor , Zagórska Irwina , Rożynkowa Danuta
Published: December 2017

Male adult albino rats fed ad libitum diets containing 50% extremely saturated vegetable fats (rape seed oil, iodine value 4 and soya bean oil, iodine value 9) showed marked weight reduction, with disappearance of body fat within a period of 6 weeks. The depot fat was not restored after 10 weeks of refeeding a control diet. The mechanism by which extremely saturated fats cause depletion of body fat cannot yet be clearly defined. Further investigations concerning the caloric balance, digestibility, and utilization of fats and carbohydrates are necessary. A possible explanation of the results is that extremely hydrogenated fats may inhibit lipogenesis from carbohydrates.
Effect of Na and impermeant anions on renal K transport during stopped flow
Authors: Sullivan Lawrence P.
Published: December 2017

The influence of increased urinary concentrations of NaCl and Na2SO4 upon the stop flow concentration patterns for potassium has been studied. Hypertonic NaCl and Na2SO4 solutions were infused into the renal artery of dogs before and during a period of stopped flow. The NaCl infusions increased the maximum concentration of potassium achieved during stopped flow but had no effect on the minimum concentrations reached. Na2SO4 infusions shifted the locus of the maximum concentrations of potassium to a more proximal location in the stop flow patterns whereas NaCl infusions did not. It is concluded that the minimum concentrations of potassium in the stop flow patterns are the result of increased reabsorption rather than decreased secretion due to a lack of sodium. The alteration in the pattern produced by Na2SO4 is due to the presence of the impermeant anion rather than increased sodium concentrations.
Effect of Triton WR-1339 on thyroid activity of normal guinea pigs
Authors: Leahy William V. C. , Janicki Bernard W. , McNickle Thomas F.
Published: December 2017

The effect of treatment with Triton WR-1339 on thyroid function was investigated in normal guinea pigs by using the thyroxin turnover technique. In addition, various other parameters such as the total distribution space (TDS), protein-bound iodine (PBI), and extrathyroidal organic iodine (ETOI) were investigated. It was found that in animals treated with Triton there was a more rapid disappearance of thyroxin, while the TDS, PBI, and ETOI were not significantly different from controls. It is concluded that the unchanged levels of plasma hormone suggest that Triton WR-1339 does not stimulate the thyroid gland directly. The increased rate of thyroxin disappearance could be explained by an indirect stimulation of the gland resulting from increased activity of a hormone-degrading enzyme system at the tissue level.
Electrophysiological studies of feeding and satiety centers in the rat
Authors: Morgane P. J.
Published: December 2017

Bipolar stimulating electrodes were implanted in the hypothalamus of rats to study the neural organization of the feeding and satiety "centers." Far-lateral hypothalamic stimulation provoked feeding in satiated animals and "motivated" crossing of electrical barriers to lever-press for food reward on several reinforcement schedules. Midlateral hypothalamic stimulation resulted in feeding in sated animals but never motivated grid crossing to lever-press. Medial forebrain bundle (MFB) lesions or stimulations anterior and posterior to the level of the feeding centers did not alter basic feeding behavior. Following MFB lesions, however, far-lateral hypothalamic stimulation never resulted in animals crossing an electrified grid to lever-press for food reward. Concomitant far-lateral hypothalamic and posterior periventricular stimulation inhibited grid crossing to lever-press, and, instantly suppressed this activity if already in progress. Simultaneous far-lateral hypothalamic and ventromedial (VM) hypothalamic stimulation only provoked basic feeding in sated animals. In animals feeding or lever-pressing in response to far-lateral stimulation, addition of VM stimulation slowed but did not completely suppress either activity. VM stimulation alone never provoked feeding or grid crossing, but "rebound" feeding in the sated state and nonelectrified grid crossing to lever-press resulted when this stimulation was turned off.
Prepotentials and unidirectional propagation in myocardium
Authors: Hoshiko T. , Sperelakis Nick
Published: December 2017

In frog ventricular strips bathed in Ca-free Ringer's solution containing 6–30 mm/liter Mg and treated with conditioning current pulses, propagation became impaired. An exaggerated foot, or prepotential, was consistently more prominent when the conditioned strip was stimulated from one end than from the other. Occasionally a prepotential in isolation alternated with a prepotential plus action potential response. After further treatment with current pulses, propagation failed in the direction of negative current flow. Thresholds of impaled cells were identical. Bidirectional propagation was restored in Ringer's solution. Conditioning pulses of reversed polarity induced unidirectional propagation in the reverse direction. Propagation in frog sartorius muscle was not blocked under similar conditions. Prepotentials and unidirectional propagation may be explained by junctional transmission from cell to cell.
Effect of lysergic acid diethylamide and its brom analogue on arterial hypertension in the rat
Authors: Sugaar Stephen , Fried George H. , Kalberer John , Antopol William
Published: December 2017

Subcutaneous administration of d-lysergic acid diethylamide (LSD) or 2-brom- d-lysergic acid diethylamide (BOL) markedly lowered the blood pressure of renal hypertensive rats. Drops of 50–120 mm Hg below established hypertensive blood pressure levels occurred within 48 hr after drug administration. For the following 10–14 days the pressure fluctuated, and then returned to original hypertensive levels. In normotensive control rats fluctuations of lesser absolute magnitude occurred within normal blood pressure ranges.
Exchange of inulin and dextran between blood and cerebrospinal fluid
Authors: Rothman Arthur R. , Freireich Emil J. , Gaskins James R. , Patlak Clifford S. , Rall David P.
Published: December 2017

C14-labeled inulin (mol. wt. 5,000) and C14-labeled dextran (mol. wt. 12,800 and 77,700) were studied for entry rate into CSF and steady state ratio of drug in cerebrospinal fluid (CSF) to drug in plasma, in nephrectomized dogs. For all three of these compounds the entry rates and steady state ratios were very similar. Exit rates of C14-inulin and C14-dextran (mol. wt. 77,700) were studied in nephrectomized and nonnephrectomized dogs. The exit rates were rapid and very similar for the two compounds. Acetazolamide increased the steady state ratio and decreased the exit rates significantly. These data suggest the presence of leaks in the blood CSF barrier of at least 60 A in diameter and indicate that bulk flow of CSF from the subarachnoid spaces to the venous system is an important means of exit of substances present in the CSF. Compounds which enter the CSF slowly fail to achieve diffusion equilibrium because of their relatively rapid exit by means of bulk flow.
Neurogenic factors and angiotensin in etiology of hypertension
Authors: Taquini Alberto C. , Blaquier Pedro C. , Bohr David F.
Published: December 2017

Destruction of the central nervous system by pithing produced a much greater fall in pressure in the renal hypertensive than in the normal rat. The average postpith pressures in the two groups were identical. If pithing was done while angiotensin was being infused into a normotensive rat the pressure fell more slowly and did not reach as low a level as it did following pithing in the hypertensive rat. Although it is not reasonable to interpret these findings as indicating that renal hypertension is caused by an increase in neurogenic tone, it appears unlikely that renal hypertension can be due to the direct pressor action of circulating angiotensin.
Oxygen and carbon dioxide permeability of subcutaneous pockets
Authors: Van Liew Hugh D.
Published: December 2017

Uptake rate of a gas from a rat's subcutaneous gas pocket was divided by the surface area and by the apparent pocket-to-tissue tension difference to yield an exchange coefficient, K'. Values in (ml x 10–4)/(min cm2 atm) were O2, 6.6; CO2, 150; and N2, 2. Blood flow in adjacent tissue appeared to have little influence on uptakes of O2 and CO2, since the K'co2:K'o2 ratio indicated that the uptakes were governed by diffusion alone, and drastic alteration of blood flow (death of the animal) decreased K'o2 by only 10%. In contrast, blood flow apparently affected N2 uptake. Because O2 and CO2 uptakes were not blood flow limited, K'o2 and K'co2 are estimates of true permeability coefficients; the calculated permeability coefficient for N2 is 3.3 (ml x 10–4)/(min cm2 atm). Comparison shows the pocket surface to be 1/50–1/150 as effective for O2 transfer as the lung. Finally, corrections are calculated for pocket-to-tissue pO2 and pCO2 differences in gas pockets used for tissue tonometry.
Evidence that induced histamine is an intrinsic regulator of the microcirculatory system
Authors: Schayer Richard W.
Published: December 2017

Evidence is presented that mammals possess an inducible form of histidine decarboxylase, associated anatomically with the microcirculation, which synthesizes histamine at a rate determined by the needs of the tissues for blood under various environmental conditions. Some supporting evidence is: a) microcirculatory changes and histidine decarboxylase activation follow the same stimuli, occur at the same anatomical sites, have parallel time relationships, and are both essentially autonomous; b) histamine can reproduce all the microcirculatory changes of the slow phase of inflammation; c) the inducible enzyme has been found in every tested vascular tissue of the mouse; d) such diverse stimuli as increased room temperature, infection, and injection of reticuloendothelial system activators elicit changes in histidine decarboxylase activity consistent with microcirculatory homeostasis; e) certain poorly understood observations on the glucocorticoids, e.g., their vasoconstrictive action and the increased need for them during inflammation or infection, are compatible with the existence of a vasodilator substance, associated with small blood vessels, which may be produced at an increased rate either locally or systemically.
Mechanisms of edema in experimental nephrosis
Authors: Kalant N. , Gupta D. Das , Despointes R. , Giroud C. J. P.
Published: December 2017

In a study of nephrosis induced experimentally by antiserum or by the aminonucleoside of puromycin, it was demonstrated that edema in the former type was transitory, was not associated with endogenous hyperaldosteronism, and could be induced in adrenalectomized animals. The onset of sodium retention, leading to the edema, preceded marked proteinuria. It was associated with a profound reduction in inulin clearance, inability to excrete a sodium load, and an increase in plasma volume. The disappearance of edema was associated with recovery of ability to excrete a sodium load and with a return of inulin clearance almost to normal. It is concluded that the edema was primarily due to temporary renal impairment of Na excretion. In aminonucleoside nephrosis, edema was normally dependent on increased aldosterone production. High Na intake, however, led to edema in the absence of aldosterone, probably because of the presence of a relatively mild degree of impairment of Na excretion, which alone was insufficient to result in edema when Na intake was at a normal level.
Effects of ether anesthesia on myocardial metabolism in dogs
Authors: Galla Stephen J. , Henneman Dorothy H. , Schweizer Hans J. , Vandam Leroy D.
Published: December 2017

Following the insertion of polyvinyl catheters into the aorta, pulmonary artery, and coronary sinus of dogs, metabolic studies of the heart were performed on intact, fasting animals. During ether anesthesia there was an increase in the arterial concentrations of glucose, lactate, and pyruvate, but a decrease in the concentration of unesterified fatty acids (UFA). Myocardial extraction of lactate, pyruvate, and UFA was a linear function of their arterial concentrations, but the extraction of glucose varied considerably. A rise in the myocardial RQ was associated with the increased extraction of carbohydrates. The decrease in the arterial concentration and myocardial extraction of UFA was thought to result from the greater availability of carbohydrate substrates. Ether anesthesia produced alterations in the pattern of myocardial metabolism, but did not seem to impair the over-all extraction of carbohydrates or UFA.
Electrotonic and chemical effects on minimal gradient requirements for cardiac muscle
Authors: Ushiyama Junji , Brooks Chandler McC.
Published: December 2017

The thresholds to rectangular pulses and the minimal gradient requirements for excitation of trabecular muscles from dog hearts were determined. Catelectrotonus lowered thresholds and shortened the minimal gradient or lambda (λ). Anelectrotonus raised thresholds and greatly prolonged lambda. Low calcium lowered threshold and increased lambda, whereas high calcium raised the threshold and shortened lambda. Quinidine and dinitrophenol had little effect on threshold but prolonged lambda. Cyanide also had little effect on threshold but shortened lambda. Urethan and cocaine slightly raised thresholds and shortened lambda. There is thus no correlation between changes in threshold and changes in minimal gradient (λ). The significance of lambda is not known.
Adrenocortical response during corrected and uncorrected hypercapnic acidosis
Authors: Mittelman Arnold , Dos Serge J. , Barker Harold G. , Nahas Gabriel G.
Published: December 2017

Adrenal venous flow rate and cortisol synthesis have been measured in dogs subjected to hypercapnic acidosis before and after intravenous administration of 0.34 mm/kg of tris (hydroxymethyl) amino methane (THAM). A comparison was made of adrenal venous, peripheral venous, and arterial blood, pH, pCO2 and O2 saturation. During uncorrected hypercapnic acidosis the concentration of cortisol increased while adrenal venous flow rate decreased, but there was a significant increase in the minute output of cortisol. With the concomitant administration of 0.34 mM/kg THAM, adrenal venous flow rate doubled. However, since this enhanced flow rate was accompanied by a sharp reduction in cortisol secretion, the minute output of cortisol returned to control levels. The possibility of a direct effect of THAM on the adrenal vascular bed and synthetic processes is discussed. Throughout all the above experiments adrenal venous blood resembled arterial blood rather than peripheral blood in its pCO2, O2 saturation and pH.
Hypotensive mechanisms of pulmonary insufflation in dogs
Authors: Maulsby Robert L. , Hoff Hebbel E.
Published: December 2017

To differentiate between the mechanisms which have been proposed to account for the hypotensive effect of pulmonary insufflation, cyclic volume changes of the right ventricle were qualitatively monitored by means of a variable resistance strain gauge sutured to the right ventricular wall. Artificially created decreases in venous return as well as cardiac tamponade of a degree sufficient to produce hypotension for brief periods were found to decrease the volume of the right ventricle. Increased right ventricular outflow resistance, however, produced a marked increase in right ventricular volume. With brief periods of hypotensive levels of pulmonary insufflation, right ventricular volume was found to increase in the animal with a wide-open chest; the volume decreased with the chest closed. It is concluded that in the open-chest condition the hypotensive mechanism of pulmonary insufflation is an increase in pulmonary vascular resistance, whereas in the closed-chest condition decreased venous return, cardiac tamponade, or both are predominantly responsible for the hypotension.
Effects of extracorporeal oxygenation of venous return on pulmonary artery pressure
Authors: Chadduck William M.
Published: December 2017

Pulmonary arterial hyperoxemia was produced in anesthetized, open-chest dogs by means of an extracorporeal oxygenator with an inflow system which prevented right atrial pressure from exceeding 7–10 cm of blood. No significant changes in pulmonary artery pressure were found when pulmonary arterial oxygen saturation was elevated to 80–99%. The elevated pulmonary artery pressure associated with systemic arterial hypoxemia was reduced by extracorporeal oxygenation of venous return. The use of such a system for attainment of tolerable levels of systemic arterial oxygen saturation in patients with acute disorders of pulmonary alveolar-capillary gas exchange is discussed.
Localization of radiomagnesium in puppies: radioautographic study of heart and bone
Authors: Glaser Warren , Gibbs William D.
Published: December 2017

Densitometer scans were made of radioautographic images of puppies' hearts and bones produced by magnesium 28. The puppies' renal pedicles were ligated prior to intravenous injection of radioactive magnesium. The puppies were killed 15–20 hr after injection. The densitometer scanning of the heart radioautographs showed the highest densities present in the interventricular septum followed by the left and right ventricular walls. These data are in agreement with those reported for radioassay of magnesium 28 in the heart. The radioautographic images of femurs of puppies showed highest densities produced by magnesium 28 present in the epiphyseal line. Assays for magnesium 28 confirmed that the epiphyseal line contained higher concentrations of the radioisotope than did the diaphyses or epiphyses. There was no statistically significant difference between concentrations of radiomagnesium in epiphyses and diaphyses. Binding of magnesium to protein was found to be 16.3% when determined by ultrafiltration through cellophane.
Influence of venous and arterial pressures on loudness of dog heart sounds
Authors: Sloan A. W. , Jarvis J. F.
Published: December 2017

With heart-lung preparations of ten large dogs, heart sounds were recorded from the exposed right ventricle simultaneously with records of venous pulsation, electrocardiogram, and arterial blood pressure. Arterial pressure readings were corrected to allow for the drop in pressure which occurs in the preparation between the aorta and external circuit. Venous pressure was altered by raising or lowering the venous reservoir, arterial pressure by altering resistance to flow through the external circuit. Heart rates were very constant except for gradual slowing during the experiment. Increasing the venous pressure increased the cardiac output and the amplitude of the first heart sound; the amplitude of the second sound usually diminished. Increasing the arterial pressure from low to hypertensive levels increased the amplitude of the first heart sound; the amplitude of the second sound increased to an aortic pressure of 120–140 mm Hg, beyond which it diminished. The third and fourth heart sounds were not recorded sufficiently frequently to merit analysis.
Effect of sympathectomy on pulmonary embolism-induced lung edema
Authors: Kabins S. A. , Fridman J. , Kandelman M. , Weisberg H.
Published: December 2017

A localized pulmonary infarction was produced by injecting a starch suspension into the pulmonary artery wedge position of one lung lobe in pentobarbitalized dogs, and the effect of bilateral surgical removal of the sympathetic chain was determined. Edema is significantly inhibited in ipsilateral and contralateral lung lobes of sympathectomized dogs. It is concluded that the sympathetic nervous system plays a major role as an efferent path in reflex production of pulmonary edema by starch emboli in the dog. There is, incidentally, evidence that sympathectomy lowers the pressure gradient between the pulmonary artery and pulmonary arterial wedge position in the dog.
Inhibition of cephalic and antral phases of gastric secretion by antral chalone
Authors: Thompson James C. , Lerner Harvey J. , Tramontana Jorge A.
Published: December 2017

The effect of antral acidification on the antral and cephalic phases of gastric secretion has been studied. Cross-transfusions were carried out between pairs of dogs in which blood from the portal vein of one dog was administered to another dog with a denervated fundic pouch. Transfusion of blood collected during acidification of the antrum resulted in a diminution of Heidenhain pouch acid secretion in response to food and to topical acetylcholine of 64% and 83%, respectively. The effect of antral acidification on gastric secretion stimulated by insulin hypoglycemia was studied in dogs prepared with Pavlov and isolated antral pouches (innervated and denervated). Irrigation of the antral pouch with .1 n hydrochloric acid resulted in a 92% decrease in Pavlov pouch acid output.
Phosphate release from dog erythrocytes
Authors: Ginski John M. , Thomson John F. , Omachi Akira
Published: December 2017

P32 release from dog erythrocytes previously incubated with radioactive inorganic phosphate was investigated. Under both aerobic and anaerobic conditions, apparent activation energies of similar magnitude, 25,000 cals/mole, were obtained. However, P32 release was lower in the absence of oxygen and greater in the presence of iodoacetate. These results suggest that the cellular pool from which P32 is released is accessible to glycolytic enzymes and that the rate of P32 release is related in some manner to the orthophosphate concentration in the precursor pool.
Carbohydrate metabolism and electrolyte content of rabbit diaphragm in vitro: effect of Na pyruvate
Authors: Young Ho Lee , Edelman I. S.
Published: December 2017

Effects of carbohydrate intermediates on conservation of electrolyte gradients in muscle were studied by incubating segments of rabbit diaphragm in substrate-free media or media containing either 5.6 mm glucose, fructose-1, 6-diphosphate, pyruvate, or α-ketoglutarate. These were without effect on Na+-K+ gradient in glycogen-rich diaphragm. Loss of K+ and gain of Na+ were slightly greater in pyruvate- than in glucose-fortified media. Glycogen-poor diaphragm, however, lost considerably less K+ and gained less Na+ in glucose than in substrate-free media. Other substrates did not reduce decay of electrolyte gradients. Loss of K+ was 19% greater with α-ketoglutarate, 33% with fructose-1,6-diphosphate, and 51% with pyruvate than with glucose. Sodium gain was accelerated by 8%, 16%, and 49% with α-ketoglutarate, fructose-1,6-diphosphate, and pyruvate, respectively. Only pyruvate facilitated chloride accumulation in muscle. Although the ability of glucose to decelerate loss of K+ and gain of Na+ in glycogen-poor diaphragm agrees with the hypothesis that Na+-K+ transport is ATP dependent in muscle, inhibitory effects of pyruvate and fructose-1,6-diphosphate remain to be explained.
Determination in vivo of regional circulatory dynamics in intact intestine
Authors: Bacaner Marvin B. , Pollycove Myron
Published: December 2017

A radioisotope technique employing a specially designed and critically shielded detector positioned in the gut lumen is utilized to monitor in vivo beta particle radioactivity in the circulation. The short range of the P32 beta in tissue (0.8 mm half thickness) is suited for this procedure because, with appropriate shielding, detected activity is limited to that contained in the blood perfusing the intestine surrounding the counter, with adjacent loops excluded. Regional blood volume is calculated from the regional counting rate of circulating P32-labeled red blood cells; regional blood flow is estimated from the local blood dilution curve. The effects of a variety of experimental maneuvers on circulatory dynamics are presented. Acetylcholine decreases regional blood flow but increases regional blood volume while cardiac output is increased. In contrast, l-norepinephrine appears to decrease both regional blood flow and regional blood volume with cardiac output relatively unchanged. This technique can be used in human subjects to evaluate the relation of regional intestinal circulation to regional function and pathology.
Comparison of rates at which albumin enters walls of small and large aortas
Authors: Duncan Leroy E. , Buck Katherin
Published: December 2017

The rate of entrance of albumin into the inner layer of aortic wall is known to correlate directly with aortic width when the variation in aortic width depends on the regions of the aorta considered. In the present study albumin was found to enter the inner layer of large aortas no faster than it enters that of small aortas. Thus the entrance of albumin into the inner layer of aortic wall does not correlate directly with aortic width when the variation in aortic width depends on the over-all aortic size.
Anticlotting activity of phosvitin on chicken blood in vitro
Authors: Sato Koji , Homma Kazutaka , Gotoh Jiro
Published: December 2017

Phosvitin, a phosphoprotein isolated from the vitellin of egg yolk, prolonged the whole blood clotting time in the chicken blood in vitro. The degree of phosvitin's inhibition of coagulation was inversely related to the level of egg-yolk-like material in plasma induced by estrogen.
Analysis of clearance of intra-arterially administered labels from skeletal muscle
Authors: Hyman Chester , Lenthall Jim
Published: December 2017

Clearance of isotope from muscle has been determined after labeling by intra-arterial infusion. If the labeling is done with normal circulation through the muscle, subsequent vasodilatation does not increase clearance. However, if muscle is labeled when dilating procedures have opened the vascular bed, subsequent dilatation or modification in effective blood flow is reflected in the clearance. Conditions for effective labeling are discussed. It is concluded that each capillary serves a limited domain of tissue fluid and that capillaries outside this domain cannot contribute to the exchange of solutes there. The findings are also consistant with the argument that blood flow in a single capillary is almost all-or-none and that, in resting muscle, nutritional blood flow is restricted to specific preferential capillary channels which remain open at all times. These findings explain some earlier paradoxes in clearance of intra-arterially administered labels.
Rate of disappearance of arginine vasopressin from circulating blood in the dog
Authors: Share Leonard
Published: December 2017

The half-life of arginine vasopressin was determined in dogs anesthetized with sodium pentobarbital. The rate of disappearance of the hormone from the circulating blood could be best described by a single exponential function during the time period studied. The average half-life of antidiuretic hormone (ADH) in eight dogs was 5.9 min with a standard error of 0.8. It appeared to be independent of the total amount of ADH administered and of whether the ADH was given as a 30-min infusion or as a single short injection. The volume of distribution of ADH, estimated in three dogs, was appreciably greater than blood volume.
Increased rubidium uptake by red cells during pregnancy
Authors: Lowenstein Jerold M.
Published: December 2017

The avidity of red cells for Rb86, a tracer of potassium in biological systems, was measured before, during, and after pregnancy. There was a gradual rise in rubidium uptake throughout pregnancy. The average uptake at 8 months' gestation was 50% higher than control levels; 6 weeks postpartum the uptake had decreased, but not to the control value.
Localization of blood pressure regulating and erythropoietic functions in rat kidney
Authors: Sokabe Hirofumi , Grollman Arthur
Published: December 2017

The cortex and medulla were removed separately from the kidneys of rats in order to localize the site of the blood pressure regulating and erythropoietic functions of this organ. The medulla was also destroyed by injecting vinylamine and by occlusion of the renal vein. The effects of these operations suggest that the blood pressure and erythropoietic functions of the kidney reside in the cortex and not in the medulla as has been claimed.
Role of abdominal viscera in the hyperkalemia produced by hypercapnia
Authors: Long David M. , Clancy Richard L. , Brown E. B.
Published: December 2017

The changes in plasma potassium concentration during and following breathing of high CO2 mixtures were determined in dogs subjected to 1) enterectomy, 2) pancreatectomy, 3) hepatectomy, and 4) abdominal evisceration. Plasma potassium increased during the hypercapnia and increased still further in the immediate posthypercapnic period. The direction of these changes was the same as those in the control animals although some quantitative differences were observed. It was concluded that the hyperkalemia was not supplied by the liver, pancreas, or stomach and intestines since it appears in the absence of any or all of these organs.
Effect of caffeine on cardiac contractile activity and radiocalcium movement
Authors: Nayler Winifred G.
Published: December 2017

Caffeine induced a positive inotropic response in toad ventricular muscle. The magnitude of the inotropic response was influenced by the concentration of Na+ and Ca++ in the perfusate and by the rate of stimulation. Caffeine abolished poststimulation potentiation and the "staircase" phenomenon, and evoked an increase in the inward and outward movement of Ca45. The positive inotropic activity of caffeine can be related to the changed movement of Ca++.
Effect of norepinephrine on plasma free fatty acids in dogs treated with reserpine
Authors: Abboud Francois M. , Wendling Michael G. , Eckstein John W.
Published: December 2017

Some adrenergic blocking drugs reduce the mobilization of free fatty acids (FFA) in response to administration of catecholamines. The present experiments were done to see if potentiation of the pressor effect of norepinephrine by reserpine is accompanied by a greater increase in plasma FFA. Norepinephrine was infused intravenously into 16 anesthetized dogs. Eight of them had been treated with reserpine, 0.25 mg/kg daily, intraperitoneally for 2 days; the others were not treated. Arterial blood samples were drawn before, during, and after norepinephrine for determination of plasma FFA concentrations. Systemic arterial blood pressure was measured continuously. In the treated animals the maximal increase in arterial blood pressure as well as the progressive increments in FFA concentration were greater than in the untreated dogs. The experiments indicate that potentiation of the pressor response to norepinephrine after reserpine is accompanied by a greater FFA response.
Mechanism of bilirubin excretion by avian kidney
Authors: Williamson I. , Robinson R. R. , Owen E. E.
Published: December 2017

Renal mechanisms of bilirubin excretion were evaluated during an infusion of either nonconjugated (crystalline bilirubin suspension) or conjugated bilirubin (human bile) into one leg vein of the chicken according to the technique of Sperber ( Nature 158: 131, 1946). Progressive elevation of the systemic plasma concentrations of total and direct-reacting bilirubin was always associated with the prompt appearance of bilirubinuria. Urine bilirubin consisted solely of the direct-reacting component, and neither plasma nor urine bilirubin was ultrafilterable. Despite the production of dissimilar peritubular plasma concentrations of the two test substances, unilateral differences of bilirubin excretion were not observed. Changes of bilirubin excretion directly paralleled those of estimated "filtered" load in all instances. Although the exact mechanism is unclear, the results indicate that the excretion of direct-reacting bilirubin is determined by glomerular function alone. Evidence of a tubular secretory system was not obtained.
Effect of high spinal section on established lactation in the rabbit
Authors: Mena Flavio , Beyer Carlos
Published: December 2017

Disconnection of nerve pathways between the mammary glands and the brain was performed in rabbits by means of high spinal transection (T2) and anterior mammectomy. These procedures resulted in cessation of lactation. However, if oxytocin was administered, lactation continued, though at a reduced level. Administration of ACTH or prolactin had a clearly beneficial effect on the postoperative milk yields. It is concluded that milk synthesis continues, though at a lesser rate, in the absence of neural connections between the mammary glands and the brain.
Sodium and potassium in canine gastric mucosa and smooth muscle
Authors: Davenport Horace W.
Published: December 2017

Sodium content of unstimulated canine gastric mucosa of the body area measures 71 ± 1 mEq, of pyloric gland area, 75 ± 1 mEq, and of gastric smooth muscle, 73 ± 1 mEq/kg wet wt. Potassium content of these tissues is 65 ± 1, 58 ± 1, and 72 ± 2 mEq/kg wet wt., respectively. Volume of distribution of radioiodinated serum albumin (Risa) is 71 ± 8, 104 ± 16, and 45 ± 10 ml/kg wet wt. Erythrocyte content is 13 ± 1, 7 ± 1, and 8 ± 1 ml/kg wet wt. Tissues also were analyzed after 150 min of stimulation with histamine and methacholine, the only significant changes being a fall in sodium content of body mucosa and pyloric gland area. Values for extravascular sodium and potassium were calculated by subtracting amounts in Risa space and erythrocytes from total tissue values. On stimulation, values for extravascular sodium tend to fall and those for potassium tend to rise. Sodium of all the tissues comes to within 90% of equilibrium with radiosodium (Na24) in plasma within 5 min, and only 3–5 mEq/kg wet wt. of sodium in the tissues fails to equilibrate with plasma Na24 in 150 min.
Stop-flow analyses of mepiperphenidol and mecamylamine in the dog
Authors: Pilkington Lou Ann , Keyl M. Jack
Published: December 2017

The renal tubular excretion of mepiperphenidol was studied in dogs utilizing the stop-flow technique. Secretion of mepiperphenidol was shown to be localized in the proximal part of the nephron. The tubular excretion of mecamylamine was studied by this technique during acidification and alkalinization of the urine. Secretion of mecamylamine was shown to occur in the proximal area of the nephron irrespective of the urinary pH. The distal area of the tubule was shown to be the site of reabsorption of the base when the urine was alkaline. It was also shown that the secretion and the reabsorption of mecamylamine can occur simultaneously in the separate areas of the nephron.