bluuebunny/crossref_metadata_2025 huggingface dataset:
Respiratory centers in the albino rat
Authors: Ondina D. M. , Yamamoto W. S. , Masland W. S.
Published: December 2017

The organization of the central nervous system mechanisms involved in respiration in the albino rat as shown by electrical stimulation and surgical transection is similar to that in other species previously studied. Areas of the medulla producing inspiratory or expiratory movements on stimulation are distinct and separated. The inspiratory center occupies about 1.1 cu mm on each side and overlies the rostral one-third of the inferior olive. The expiratory center is somewhat more diffuse and lies dorsal and caudal to the inspiratory center. Serial transections produce the usual phenomena which lead to the identification of the pneumotaxic center and apneustic center. In the medullary rat ataxic breathing shows a dissociation of the inspiratory-expiratory sequence in breathing.
Mechanism of action of thiosemicarbazide and Metrazol on cerebellar and cerebral activity in the cat
Authors: Dunlop C. W. , Adey W. R. , Killam K. F. , Brazier M. A. B.
Published: December 2017

Neocortical wave activity during thiosemicarbazide (TSC) induced seizures was less regular and lower in amplitude than cerebellar wave activity. The regular progression of slow activity seen with TSC in successive seizures was not encountered with Metrazol. Following TSC injection, dendritic and subcellular d.c. potential gradients became increasingly negative up to the first seizure discharge. Following the first seizure discharge the d.c. level decreased in negativity. Examination of the neocortical d.c. gradient after TSC injection failed to reveal a predictable and sustained shift. Purkinje and cortical cells which had responded to repetitive sciatic stimulation became inaccessible to such stimulation following TSC injection and the positive phase of individual cells decreased about 30% in amplitude and almost doubled in duration. Pyridoxine hydrochloride gradually arrested TSC induced seizures. Metrazol had little effect on the cerebellar and neocortical d.c. gradients and unit action potentials. Following TSC injection, thresholds for both hyperpolarization and depolarization effects observed in the cerebellar cortex were markedly raised.
Carbonic anhydrase inhibition and brain electrolyte composition
Authors: Koch Alan , Woodbury Dixon M.
Published: December 2017

The effects of acetazolamide on cellular electrolyte composition and acid-base status in the brain of rats were compared with the effects of carbon dioxide and diphenylhydantoin. In addition, the effects of acetazolamide on radiosodium turnover in the brain was determined. Acetazolamide decreased intracellular sodium concentration, increased intracellular potassium concentration, and had little effect on intracellular pH. The drug reduced the rate of turnover of radiosodium in the brain. The observations that acetazolamide reduced intracellular sodium concentration and reduced the rate of sodium turnover are interpreted to indicate that the drug decreases the permeability of the neuronal membrane to sodium ion. The reduction in permeability of the neuronal membrane to sodium ion is considered to be a possible mechanism for the anticonvulsant action of this agent.
The QRS electrocardiogram, epicardiogram, vectorcardiogram and ventricular excitation of swine
Authors: Hamlin Robert L.
Published: December 2017

The ventricular activation process of normal pigs as estimated qualitatively from body surface potentials and epicardial electrograms is similar to that accurately described for the dog. Ventricular excitation may be divided sequentially into three components: interventricular septal from left to right, ventricular free-wall from endocardium to epicardium, and septal and ventricular basilar in an apico-basilar direction. The differences between the body surface potentials recorded from the dog and from the pig lies in the greater dorsal magnitude of the terminal basilar forces in the pig.
Bioelectric responses in situ of mammalian nerves exposed to X-rays
Authors: Bachofer C. S. , Gautereaux M. E.
Published: December 2017

X-irradiation of ventral caudal nerves of rat in vitro produces an increase in spike amplitude and in conduction velocity of the propagated impulse. In order to determine to what extent these results are due to the artificial environment in which the nerve was placed, a series of experiments was carried out in which the bioelectrical effects of x-rays on the ventral caudal nerve in situ were investigated. Immediately upon x-irradiation there was a considerable increase in spike amplitude and a somewhat lesser increase in conduction velocity. Following the increase there was a deterioration with ultimate block of conduction. At equal doses the in situ preparations were slightly more radiosensitive. There was a remarkable similarity in the responses of nerves irradiated in vitro and in situ. The effect cannot be attributed to such environmental factors as a change in temperature of the preparation or to alterations in the blood supply. The effect is apparently due to an altered condition of the nerve fiber itself, since the x-rays do not act synergistically to produce the enhancement here reported.
Evidence for the independence of K- and HCl-efflux into gastric secretion
Authors: Hollander Franklin , Colcher Henry
Published: December 2017

Further evidence is presented that the concentration of K in gastric secretion varies extensively (0.3–12.3 mEq/L.) with time following histamine injection—in refutation of the previously reported constancy. Interrelations among the concentrations of major electrolytes and volume rate following single subcutaneous injections were analyzed for individual experiments (7 dogs) and also statistically. Concentrations of neutral Cl, Na, and Na plus K varied inversely with total acidity, according to the usual rectilinear relation. K was wholly uncorrelated with acidity ( r = –0.13) and volume rate ( r = 0.08). The only regularity in K behavior was in relation to time following histamine administration. The characteristics of these concentration-time curves suggest that histamine triggers the efflux of K into gastric secretion by some mechanism which is independent of HCl efflux and, therefore, of the formation of parietal secretion. The two processes may be initiated simultaneously, but proceed thereafter in wholly independent manner. Several different explanations suggest themselves, but the data are still inadequate for preferential acceptance of any one of them.
Placental transfer of phosphorus in sows maintained on high and low levels of dietary manganese
Authors: Newland H. W. , Davis G. K. , Wallace H. D.
Published: December 2017

Placental transfer of phosphorus was studied in 16 young sows which had been maintained on high and low levels of dietary manganese during their first gestation. Radiophosphorus absorption and the concentration of total phosphorus were found to be directly related to the weight of the fetus. Also, the absorption of P32 and the concentration of phosphorus was essentially the same in fetuses from sows on different levels of dietary manganese. Fetal femurs metabolized P32 more rapidly than did maternal femurs, fetal hearts and fetal livers, while maternal livers showed more activity than any other maternal or fetal organ. Small fetuses at the 60th and 80th day of gestation had a higher specific activity than larger fetuses of the same age. Radiophosphorus placental transfer rate increased steadily during the last half of pregnancy.
Modification of BSP metabolism by bile stasis and liver injury
Authors: Krebs John S. , Brauer Ralph W.
Published: December 2017

Excretion of BSP into bile by the liver of the rat was prevented or reduced by temporary bile stasis, carbon tetrachloride intoxication, or whole-body x-ray. BSP was injected, bile was collected for a standard period of time and the BSP excreted into bile was analyzed for distribution among its metabolic products. An increase was found in the compound representing the apparent terminus of the metabolic sequence, indicating that metabolism of BSP had continued during the delay in excretion. The results suggest that an immediate consequence of bile stasis is an arrest of the net secretion of BSP, whether fluid continues to be secreted or not. The possible relationship of the effects of the delay in excretion of BSP to the apparent concentration of BSP in plasma is pointed out.
Significance of changes in blood glucose specific activity following insulin administration
Authors: Landau Bernard R. , Leonards Jack R.
Published: December 2017

Galactose-1-C14 was administered to dogs receiving a continuous nonradioactive glucose infusion. A rapid rise followed by a gradual decline in plasma glucose specific activity and total activity was observed. However, following insulin administration, while there was an increased disappearance of total counts from the plasma, felt to be a reflection of increased glucose utilization, there was for long periods either a constancy of glucose specific activity, or even a rise in specific activity above preinsulin values. These changes are felt to be consonant only with the entry of glucose of higher specific activity into the circulating blood than that already present. Such glucose presumably could arise from the outer tiers of glycogen formed from galactose during the preinsulin period. The experiments provide experimental proof that cessation of a decline in circulating glucose specific activity following insulin administration need not be interpreted as a cessation of hepatic glucose production.
Effects of insulin on glucose and palmitate metabolism by resting and stimulated rat diaphragms
Authors: Fritz Irving B.
Published: December 2017

The metabolic fate of glucose in isolated muscle after addition of insulin was shown to be dependent upon the functional state of the tissue. While nonstimulated muscle responded primarily with an increased incorporation of glucose into glycogen, stimulated muscle showed predominantly an increased conversion of labeled glucose to CO2 following insulin addition. The oxidation of palmitic-1-C14 acid by muscle was not influenced by the presence of insulin. Ryanodine, used as a chemical agent for inducing contraction of diaphragm, resulted in stimulation of oxygen consumption, fatty acid oxidation and glucose oxidation to an extent comparable to that previously achieved with electrical stimulation of muscle. The conclusion was reached that insulin increased the oxidation of glucose but not of palmitate, and that the specific metabolic fate of intracellular glucose is not influenced by insulin. The data are discussed in relation to the prevailing theory that insulin acts by increasing permeability of muscle cell membranes to certain substrates.
Role of anions in the fibrillatory process
Authors: Holland William C. , Sekul Antonio A.
Published: December 2017

Replacement of Cl in Ringer's solution with SCN, I, Br and NO3 prevents or diminishes the incidence of acetylcholine-induced atrial fibrillation. The relative order of effectiveness being SCN > I > Br > NO3. The thesis is developed that maintenance of fibrillation depends upon the rate of entry of Cl into a thin barrier, probably the cell membrane. The antiarrhythmic properties of foreign anions result from their adsorption in this barrier, thereby impeding the entry of Cl.
Ferritin and antiferritin serum treatment of dogs in irreversible hemorrhagic shock
Authors: Rothstein David A. , Rosen Seymour , Markowitz Abraham , Fuller John B.
Published: December 2017

A classic explanation for the development of irreversibility of transfusion therapy in hemorrhagic shock has been the so-called ‘VDM’ theory, which postulates that ferritin (VDM) is released from the anoxic liver during shock and adversely affects the vasculature, leading to irreversibility. In the present experiment, several groups of dogs, subjected to standardized procedure for producing hemorrhagic shock, were treated with either antiferritin serum, purified ferritin, normal rabbit serum or saline. Neither vascular compensatory mechanisms nor survival rates were affected by any of the treatments. The experiment has thus failed to indicate that circulating ferritin is a major factor in the genesis of irreversible hemorrhagic shock, and it is concluded that ferritin is a concomitant and not a cause of irreversible hemorrhagic shock in dogs.
State of creatine in mammalian heart muscle
Authors: Lee Y. C. P. , Dewall R. A. , Visscher M. B.
Published: December 2017

Studies were performed on the total creatine, phosphocreatine and inorganic phosphate content of rabbit ventricular muscle from animals sacrificed under various conditions. The highest values of phosphocreatine, averaging 59.6% of the total creatine, were found in hearts arrested by intra-aortic infusion of alkaline potassium citrate solutions. Approximately the same values were found after sodium citrate arrest. Potassium chloride arrest resulted in a finding of only half as much phosphocreatine. Hearts removed without previous arrest likewise showed phosphocreatine values far below those found after citrate arrest. Acetylcholine arrest did not yield high values. Animals sacrificed by stunning, followed immediately by artificial respiration with 100% O2 showed the lowest quantities of cardiac phosphocreatine. Adrenaline administration to the animal prior to potassium citrate arrest was followed by very low phosphocreatine levels. The inorganic phosphate content of rabbit heart muscle is in general inversely proportional to the phosphocreatine, and directly proportional to the free creatine levels. Assuming a linear correlation one finds that there appears to be 75 mg% of free creatine in the rabbit ventricular muscle at the time of instantaneous arrest under optimal conditions.
Hepatic clearance of indocyanine in the dog
Authors: Stekiel William J. , Kampine John P. , Banaszak Edward F. , Smith James J.
Published: December 2017

The clearance and extraction by the liver of the dye, indocyanine green, was studied in dogs anesthetized with sodium pentobarbital (30 mg/kg). A simultaneous comparison ‘ in vivo’ indicated that within experimental error indocyanine space equals Evans blue space. Additional in vitro experiments suggest that indocyanine space is a reasonably satisfactory measure of plasma volume. Adequate mixing of the injected dye occurs within 2–3 minutes after injection. From 2 to 20 minutes after injection, the peripheral arterial and hepatic venous decay slopes are logarithmic and easily analyzable. Right hepatic vein concentrations of indocyanine were consistently higher (3.3%) than those of the left. Most of the assumptions made in the clearance-extraction principle of measuring hepatic flow are valid. At least two factors, the obtaining of representative hepatic venous samples and determination of true extraction ratio (because of hepatic circulatory time) represent ill-defined sources of error. The soundness of the clearance-extraction principle and unique characteristics of indocyanine make the single injection method a potentially useful tool for study of hepatic blood flow.
Effects of sodium ion and solution tonicity on reactivities of hypertensive rat aortic strips
Authors: Mallov Samuel
Published: December 2017

Rats were rendered hypertensive by injecting DCA and feeding 1% NaCl solution in place of drinking water. Isometric tensions developed by strips of aorta from these rats, when exposed to a low concentration of epinephrine, were compared with tensions developed by strips from normotensive controls, under conditions of varying Na ion concentration and solution tonicity. Solutions with high Na ion concentrations (hypertonic), and normal solutions rendered equivalently hypertonic by the addition of sucrose, increased the reactivities of strips from normotensive rats, but decreased the reactivities of strips from hypertensive rats, to added epinephrine. The hypertensive rat strips manifested increases in tension in these solutions even prior to the addition of epinephrine, so that the subsequent smaller responses to epinephrine may have been related to these initial tension increases. Low sodium ion concentrations in hypotonic solutions, but not in isotonic solutions, decreased the reactivities of both hypertensive and normotensive rat strips. These results are interpreted to mean that aortas from hypertensive rats are so changed structurally and functionally, that they respond differently than do normal aortas to increased sodium ion concentrations and/or hypertonic solutions, as well as to epinephrine in such solutions.
Urea permeability of alveolar membrane; hemodynamic effects of liquid in the alveolar spaces
Authors: Cross Cecil E. , Rieben P. Andre , Salisbury Peter F.
Published: December 2017

The blood flow through isolated lungs, excised or in situ, was measured while air or isotonic lavage solution was injected into and withdrawn from the lobar bronchus under variable pressures. Lavage of isolated lobes, intubated via the lobar bronchus with cuffed endotracheal tubes, was also performed in closed-chest experiments while certain hemodynamic parameters were recorded. Urea equilibration between the blood and the alveolar fluid could be expressed as an asymptotic line; the urea concentration of the alveolar fluid reached 30% and 55% of the blood urea concentration when the lavage solution remained in the alveoli for 5 and 15 minutes, respectively. Regardless of the presence or absence of liquid in the alveoli, vascular resistance in the isolated lobe was determined by airway pressure. In closed-chest experiments the hemodynamic effects of pulmonary lavage were minimal as long as low positive and negative pressures were used to inject and withdraw the lavage solution.
Pulmonary venular responses to anoxia, 5-hydroxytryptamine and histamine
Authors: Aviado Domingo M.
Published: December 2017

In anesthetized dogs, the inhalation of 5% oxygen causes a rise in pulmonary arterial pressure but no rise in venular pressures measured by catheters with outside diameters of 0.4 mm and 1.0 mm. The venular pressure measured by the 0.4-mm catheter showed a consistent rise to 5-hydroxytryptamine. This venular constrictor response to 5-hydroxytryptamine is encountered even when pulmonary blood flow is kept constant by perfusion. The venular response to histamine is variable.
Hyperglycemic substances orginating in the pancreatoduodenal area
Authors: Galansino Giorgio , D'Amico Giuseppe , Kanameishi Doris , Berlinger Fred G. , Foà Piero P.
Published: December 2017

Glucagon, serotonin, deserpidine and the diethanolamine salt of p-tolymethyl carbinol camphoric acid ester (DTCE) were injected into the pancreatic, mesenteric or femoral artery, or into the portal or femoral vein of anesthetized normal dogs and dogs pretreated with dihydroergotamine (DHE) or with SA-97, a serotonin-blocking agent. Intraportal glucagon causes a fleeting, but a marked and significant elevation of plasma potassium and a marked and significant hyperglycemia. DHE blocks glucagon hyperkalemia, but not glucagon hyperglycemia. These effects are similar to the effects of glucagon injected into a peripheral vein and suggest that glucagon hyperkalemia may be mediated by a sympathomimetic amine. Serotonin causes a marked hyperglycemia which is not seen in animals pretreated with DHE or SA-97. Deserpidine causes an immediate and marked hyperglycemia when injected into the pancreatic artery, and a mild and delayed hyperglycemia if injected elsewhere. DTCE also causes hyperglycemia only when injected into the pancreatic artery. DHE blocks the effect of serotonin and of DTCE, but not that of deserpidine. It is suggested that more than one type of hyperglycemic substance may be produced in the area supplied by the pancreatic artery: one type which, like serotonin or the catecholamines, is blocked by DHE, and another type which, like glucagon, is unaffected by it.
Metabolism of C14-labeled acetone, acetate and palmitate in fasted pregnant and nonpregnant guinea pigs
Authors: Bergman E. N. , Sellers A. F. , Spurrell F. A.
Published: December 2017

Metabolism of acetone-2-C14, Na acetate-2-C14, and Na palmitate-1-C14 was compared in normal and pregnant ketotic guinea pigs. Expired CO2, lipids, urine, liver tissue and acetone bodies were quantitated and assayed for radioactivity. After acetone-C14 injections, pregnant ketotic, as well as nonpregnant guinea pigs injected with carrier acetone, metabolized markedly less C14 as the blood concentration of acetone was progressively elevated. The data showed that the actual milligrams of free acetone utilized remained fairly constant regardless of the size of the body acetone pool. After acetate-C14 injections, pregnant fasted guinea pigs utilized less C14 for CO2 excretion and more C14 for biosynthesis than the nonpregnant fasted group. The difference in CO2 specific activity with regard to size of the body acetate pool is discussed. After palmitate-C14 injections, the mean specific activity of the CO2 was greater in the pregnant fasted than in the nonpregnant fasted animals. Since the liver fat content of the former was lower, the data indicate a faster turnover rate of a smaller fatty acid pool.
Stabilization and rectification of muscle fiber membrane by tetrodotoxin
Authors: Narahashi Toshio , Deguchi Takehiko , Urakawa Norimoto , Ohkubo Yoshio
Published: December 2017

The mode of action of tetrodotoxin on the frog muscle fiber membrane has been analyzed with the aid of intracellular microelectrodes. Tetrodotoxin of 10–7 concentration made the applied cathodal current ineffective in producing action potential, whereas the resting potential and resting membrane resistance underwent little or no change. With 10–8 tetrodotoxin the muscle fibers responded with the small action potentials at high critical depolarizations. These results can be explained on the basis of the membrane being stabilized by inactivation of the sodium-carrying mechanism. Although delayed rectification was not observed in normal muscle fibers, it became apparent in the fibers rendered inexcitable by tetrodotoxin. This finding, together with other evidence in the existing literature, supports an applicability of the sodium theory to the frog muscle fibers.
Supersensitivity of denervated superior cervical ganglion to acetylcholine
Authors: Chien Shu
Published: December 2017

The supersensitivity of denervated superior cervical ganglion to acetylcholine was studied in cats at 2 weeks after the section of cervical sympathetic trunk on one side, with the other side as a control. The control ganglion required about four times as much of acetylcholine as the denervated side, in order to release the same amount of norepinephrine at the postganglionic endings. The relative quantity of norepinephrine released on acetylcholine administration to ganglia was determined indirectly by using the in vivo nictitating membrane as an indicator, whose responses to various doses of norepinephrine had been calibrated. The validity of such indirect determination of norepinephrine was shown by experiments in which the eyeballs were removed or the lever magnifications were made unequal. With control cats in which both cervical sympathetic trunks were cut acutely, the sensitivity of the ganglia on two sides to acetylcholine was almost equal.
Dynamic basis for sympathetic cardiac augmentation
Authors: Randall Walter C. , Kelso Albert F.
Published: December 2017

Analysis of optically recorded cardiovascular pressure pulses during sympathetic stimulation of the heart reveal a multiplicity of direct influences on the myocardium. An increased rate of pressure rise and pressure fall along with a shortened duration of contraction and relaxation indicates more synchronous myocardial contraction and a direct sympathetic influence on conductile and contractile tissues. Heart rate changes denote the well known action on nodal tissue. A decreased duration of contraction and relaxation significantly increases time available for cardiac filling, and thus permits augmented cardiac ejection without necessitating change in end-diastolic volume. The increased force and shortened duration of contraction and relaxation during sympathetic stimulation may be present even in the absence of increased ejection and augmentation of arterial pressure pulses.
True transmembrane potential curve from the surface of guinea pig ventricle: its relation to intrinsic deflection
Authors: Dower Gordon E. , Geddes Margaret A.
Published: December 2017

The monophasic curves of the potential variations between an intracellular microelectrode and a remote reference electrode when recorded at sufficiently high speed show irregular upstrokes which are made up of a steep rise and one, or more, gentle rises; the relationships between these rises vary with position on the surface of the (guinea pig) ventricle. By subtracting, electronically, the local ECG obtained from a wire-loop electrode surrounding the microelectrode the irregularities can be removed: the subtractor output yields monophasic curves with even, sigmoid upstrokes. Such curves represent the true transmembrane potential. The use of the subtractor brings out the relationship between the intrinsic deflection of the local ECG and the upstroke of the transmembrane potential curve. Because these coincide and because the latter marks the influx of sodium ions into the cell, a direct relationship between the intrinsic deflection and the entry of sodium is revealed. This adds to the significance of the intrinsic deflection and permits a more rigorous definition of it.
Factors affecting bronchial collateral flow in the dog
Authors: Auld Peter A.M. , Rudolph Abraham M. , Golinko Richard J.
Published: December 2017

A preparation is described in which the pulmonary and systemic circulations were perfused separately. The only connection between the two circulations was by way of the bronchial collateral vessels. The volume of collateral flow could be measured by recording the rise and fall in the pulmonary drainage reservoir. A ‘forward’ bronchial collateral flow and a ‘reverse’ bronchial collateral flow is described and their existence has been confirmed by radioactive iodinated serum albumin studies. Increases in systemic arterial and venous pressures have been demonstrated to cause an increase in bronchial collateral flow. Independent increases of pulmonary arterial and left atrial pressures resulted in a decrease in bronchial collateral flow, and at suitable pressures a reversal of flow was demonstrable. The data suggest the presence of two bronchial circulations with drainage into the pulmonary arterial and venous systems separately.
Lymphatics in genesis of ascites in the rat
Authors: Raybuck Harry E. , Weatherford Tim , Allen Lane
Published: December 2017

Almost total obliteration of the peritoneal lymphatic drainage in rats produced no increase in peritoneal fluid. The problem was extended to observe the effect of peritoneal lymphatic obstruction with superimposed infrahepatic portal hypertension on peritoneal fluid dynamics. For controls infrahepatic portal hypertension was produced by partial obstruction of the portal vein with an aluminum clip. In animals with peritoneal lymphatic obliteration and portal hypertension serous fluid accumulation was three times as great as in those with portal hypertension alone and resembled clinical ascites. Such findings indicate that subtotal peritoneal lymphatic obstruction alone does not appreciably affect serous fluid dynamics. However, in the presence of altered physiological mechanisms involved in serous fluid production, obstruction of the lymphatic system may play a significant role in the genesis of ascites.
Potassium flux in the isolated perfused rabbit heart
Authors: Humphrey E. W. , Johnson J. A.
Published: December 2017

The exchange kinetics of potassium in the isolated, perfused rabbit heart have been studied in relation to changes in heart rate, extracellular potassium and temperature. The intracellular potassium appeared to exist in at least two compartments, the relative size varying with the extracellular concentration of potassium. The change in the potassium flux between heart rates of 100 and 200 beats/min. was compared to a change in flux calculated on the basis of the theory proposed by Hodgkin and co-workers and electrical constants taken from the literature. The change in flux estimated from the experimental curves was somewhat smaller than that required by theory and a discussion of this result is given. The activation energy calculated for the total potassium flux into and from the cells was estimated to be from 3000 to 8000 cal/ mole and found to be a function of the potassium concentration in the perfusate.
Thermoregulatory effects of abdominal air sacs on spermatogenesis in domestic fowl
Authors: Herin Reginald A. , Booth Nicholas H. , Johnson Robert M.
Published: December 2017

In an attempt to determine if the posterior abdominal air sacs exert a cooling effect on the testes of the domestic rooster, thereby facilitating normal spermatogenesis, the air sacs were surgically removed and the testes insulated with surgical cotton. No significant difference was found in the semen quality between the control and experimental groups. Comparison of the testicular, air sac and rectal temperatures showed no significant differences. It is suggested that the air sacs do not cool the testes of the rooster and that the germinal epithelium of the rooster has adapted to the high body temperatures and produces normal spermatozoa at this temperature.
Induction of tolerance to skin homografts in rat littermates
Authors: Evans D. H.L. , Hamlyn L. H. , Hogarth Maureen
Published: December 2017

The possibility of inducing mutual tissue tolerance between pairs of rat littermates has been studied. Following splenectomy at 2–4 days extrauterine life, saline suspensions of homogenized splenic tissue were exchanged between pairs. The total amount of splenic tissue available was suspended in 0.1 ml of saline which was injected into the peritoneal cavity. Tolerance was tested by exchanging skin grafts at the age of 6 weeks. In some litters the spleens were pooled and the resulting suspension injected into all members with a view to producing a mutually tolerant group. Exchange of splenic tissue between pairs produced complete tolerance in nearly all cases where the animals survived. In cases where the spleens had been pooled only minimal evidence of tolerance was observed. The principal difficulty in these experiments was a very high mortality which was not reduced by any of the precautions taken.
Deficient synthesis of factor VII by liver tissue of fetal and newborn rats
Authors: Grodsky Gerold M. , Kropatkin Mona , Pool Judith G.
Published: December 2017

The deficiency of circulating factor VII in the newborn human being was confirmed for the newborn rat and its etiology studied. The ability of liver slices from fetal, newborn and adult rats to synthesize factor VII in vitro was compared under standard conditions. Fetal tissue had about 1/20 and newborn tissue about 1/3 the capacity of adult tissue to form this factor. Although a deficiency of vitamin K has been considered the cause of the clotting factor deficiencies at birth, supplementation of the rat tissue, either with vitamin K added to the liver slices in vitro or vitamin K given to prepartum mother rats in vivo, resulted in only minor improvement of the synthetic rate. Extracts of fetal liver were studied for the presence of an inhibitor of factor VII synthesis and extracts of adult tissue for the presence of a stimulator, but neither could be detected. It was concluded that a functional immaturity of liver enzyme systems involved in synthesis of factor VII exists at birth.
Relation of coronary flow to oxygen supply
Authors: Guz Abraham , Kurland George S. , Freedberg A. Stone
Published: December 2017

Coronary flow, heart rate, myocardial oxygen consumption and Walton strain gauge tension were determined in the isolated rabbit heart perfused with hemoglobin solutions of varying oxygen content. Perfusion was carried out under constant pressure and with the hemoglobin solution in equilibrium with 3% CO2 and 97% air under atmospheric tension. Oxygen content was varied from 2 to 18 vol. % by diluting hemoglobin with Ringer-Locke solution. Change from a higher to lower oxyhemoglobin concentration resulted in increased coronary flow; the reserve led to decreased flow. Heart rate, myocardial tension and oxygen consumption were constant at oxygen capacity above 2 vol. %.
Increase in aldosterone secretion by acute denervation of the thyrocarotid arterial junction
Authors: Gann Donald S. , Bartter Frederic C.
Published: December 2017

Dogs in which the adrenal veins had been cannulated were subjected to acute bilateral denervation of the thyrocarotid arterial junctions. Aldosterone secretion was determined before and after denervation. Denervation resulted in increased secretion of aldosterone, which was observable within 30 minutes. Dogs in which the thyrocarotid arterial junctions had been denervated 1–3 weeks previously showed resting levels of aldosterone secretion comparable to those of unoperated controls. The evidence is consistent with the hypothesis that aldosterone secretion is stimulated by reducing nerve impulse traffic in the nerves arising from the thyrocarotid arterial junctions. The return of levels of aldosterone secretion to normal 1–3 weeks after denervation suggests the presence of another system inhibiting secretion of aldosterone, such as that mediated by the vagus nerves.
Epinephrine action on glucose uptake by rat diaphragm; effect of ionic composition
Authors: Herman Marta Szabo , Ramey Estelle R.
Published: December 2017

The in vitro inhibitory effect of epinephrine on glucose uptake by the isolated rat diaphragm was reinvestigated under various experimental conditions. This effect of epinephrine was manifest only in the Krebs-Ringer phosphate incubating medium and did not occur in the Krebs-Henseleit bicarbonate medium or in the phosphate medium in which the concentration of Mg++ was increased twofold. A change in the concentration of Ca++ ions in the phosphate incubating medium did not affect the inhibition produced by epinephrine. An increase in H+ ion concentration in the phosphate medium diminished control glucose uptake as well as the inhibitory effect of epinephrine. It is suggested that the absence of in vitro inhibition of glucose uptake by epinephrine in the bicarbonate and high Mg phosphate media is due to the normal functioning of the phosphofructokinase enzyme system in these two media only. This in turn produces a faster rate of removal of glucose-6-phosphate, the product of glucose phosphorylation and glycogen breakdown. The accumulation of glucose-6-phosphate would inhibit the enzyme hexokinase, as is the case in the phosphate medium. An explanation for the conflicting reports in the literature regarding the in vitro effect of epinephrine on glucose uptake in muscle is suggested.
Effect of AET on sodium, potassium and esterases of the alimentary tract of irradiated mice
Authors: Maisin Jean R. , Popp Raymond A.
Published: December 2017

A study was made of the effect of S,2-aminoethylisothiuronium bromide hydrobromide (AET) on the changes in sodium and potassium concentrations in the walls and contents of the gastrointestinal tracts of mice exposed to 1500 r. Mice were given AET and were then irradiated. At intervals thereafter, portions of the gastrointestinal tract and its contents were analyzed for sodium and potassium in a flame spectrophotometer. In mice given AET before exposure to 1500 r, the following radiation-induced abnormalities were completely or partially corrected: decrease in potassium and increase in sodium in the wall of the small intestine; decrease in potassium in the colon wall; and increase in sodium and potassium in the contents of the stomach, small intestine and colon. Extracts from the walls of the small intestines of AET-treated or nontreated, irradiated mice were analyzed chemically for esterase activity. In AET-treated, irradiated mice, complete recovery of esterase activity was observed by day 7 after 900 r, and partial recovery occurred after 1500 r. Since AET reduces radiation damage and thereby allows recovery, the beneficial effects of the compound on the correction of electrolyte imbalance and esterase activity are ascribed to recovery of the tissues of the gastrointestinal tract.
Cellular site for prothrombin synthesis
Authors: Barnhart Marion I.
Published: December 2017

The cell type responsible for synthesis of any of the trace plasma proteins concerned in blood coagulation has not been identified before. In this study the fluorescent antibody technique was used to find out the cellular site for prothrombin synthesis. Fluorescent antiprothrombin precipitated out on bovine liver parenchymal cells containing adequate concentrations of prothrombin. The specificity of the reaction was established using various absorptive and blocking techniques. The antiprothrombins produced were species specific. Not all parenchymal cells reacted uniformly with fluorescent antiprothrombin so that groups of brilliantly fluorescing cells were seen among cells displaying dim natural fluorescence. This may mean that only a certain type of parenchymal cell produces prothrombin or that there is cyclic production of prothrombin.
Conduction in smooth muscle: comparative structural properties
Authors: Prosser C. L. , Burnstock Geoffrey , Kahn Joseph
Published: December 2017

The individual fibers of smooth muscle of high propagation velocity (e.g. esophagus) are longer and more closely packed than in those of low velocity (e.g. cat intestine). The space between fibers and within bundles calculated from electron micrographs is 4.4% for pig esophagus muscularis mucosae, 9.0–12.5% for taenia coli and cat intestine, 18.2% for the slow dog retractor penis and 39% for the nonconducting carotid artery. Predominant intercellular separation for esophagus and taenia is 700 A°, for cat longitudinal intestinal 1600 A°, dog retractor 3000 A° and carotid artery 10,000 A°. Two types of interfiber ‘bridges’ both crossed by membranes were observed. These may represent relatively low resistance pathways between fibers during conduction or they may serve a mechanical function. Vesicles are abundant beneath cell membranes and are arranged in longitudinal ridges, some 20 rows/cell. Among the myofilaments are found dark bodies which appear to be composed of noncontractile protein.
Effects of protamine and strophanthin on mitochondrial potassium, sodium and water
Authors: Share Leonard
Published: December 2017

A study was made of the effects of certain agents, which inhibit potassium transport in intact cells, on the potassium, sodium and water metabolism of isolated mitochondria. Protamine (4 mg/100 ml) induced swelling in rat liver and kidney mitochondria and impaired the ability of these mitochondria to concentrate potassium. These actions appeared to be associated with the uncoupling of oxidative phosphorylation. Protamine was without effect on the mitochondrial sodium concentration. Strophanthin at extremely high concentrations (1 gm/100 ml) was also found to induce swelling of rat liver, kidney and heart mitochondria and to interfere with the ability of the mitochondria to concentrate potassium. There was a tendency for mitochondrial sodium concentration to be elevated. It is concluded that the actions of protamine and strophanthin on mitochondria are qualitatively and quantitatively different from the actions of these substances on intact cells and that there are basic differences between the potassium concentrating mechanisms in mitochondria and in intact cells.
Experimental production of intra-arterial and intravenous thrombi in the rabbit and rat
Authors: Friedman Meyer , Byers Sanford O. , Pearl Felix
Published: December 2017

Small special segments of alloy wire (98% magnesium and 2% aluminum) were pretreated by immersion in 0.5% zinc chloride for 15–25 minutes. Such wires disintegrate by focal electrolysis when inserted in the aorta or inferior vena cava of rabbits or rats and in so doing cause the formation of relatively uniform white thrombi. In the artery of the rabbit such thrombi were quickly overgrown by intimal fibroblastic tissue which also penetrated each thrombus. In the artery of the rat, this reaction was much less luxuriant and slower than in the artery of the rabbit. It is emphasized that the late arterial sequel to this thrombus resembles a pearly plaque.
Effect of Triton on rate of removal of palmitate-i-C14 from serum
Authors: Byers Sanford O. , Cady Paxton , Friedman Mayer
Published: December 2017

The rate of clearance of injected palmitate-iC14 from the serum of hepatectomized-viscerectomized rats was measured in four animals previously treated with Triton and in four animals not so treated. The effect of Triton was to increase the rate of disappearance of the injected palmitate. A possible mechanism for this effect is discussed.
Effect of water restriction on urinary concentrating ability of K-depleted rats
Authors: Blythe William B. , Newton Margaret , Lazcano Fernando , Welt Louis G.
Published: December 2017

In order to test the possibility that the urinary concentrating defect associated with potassium depletion results from excessive water intake that accompanies potassium depletion, water intake was restricted in one half of a group of rats undergoing potassium depletion. The other one half of the group was allowed to drink ad libitum After 14 days, ability to concentrate the urine was tested in both groups as well as in two groups of control rats, one of which was allowed to drink ad libitum and the other having water intake restricted. Although both potassium-depleted groups concentrated urine less than the control groups, there was no difference in urine-concentrating ability between the two potassium-depleted groups. It is concluded that the urinary concentrating defect in potassium depletion is not due to excessive water intake.
Effect of alloxan-induced diabetes on magnesium metabolism in rabbits
Authors: Aikawa Jerry K.
Published: December 2017

In six rabbits external balance studies for magnesium were performed for 11 days after diabetes had been induced by the injection of alloxan. The only significant change observed was a decrease in mean body weight. The exchangeable magnesium content, determined with Mg28, also showed a significant decrease. In another group of 16 rabbits the relative radioactivity of Mg28 in muscle, skin, appendix, lung, liver, heart, kidney and bone was not altered by the administration of alloxan to half the group. The magnesium content of the skin was decreased, and that of the bone increased. Alloxan diabetes is associated with changes in the dynamics of magnesium metabolism which may not be demonstrable by the external balance technique.
Characteristics of cardiac tissue from adrenalectomized rats
Authors: Ullrick William C. , Brennan Betsy B. , Whitehorn William V.
Published: December 2017

In vitro measurements of strength-duration curves, refractory periods, isometric developed and passive length-tension diagrams, and active and resting respiratory rates were made on left ventricular muscle columns from 18 normal and 17 bilaterally adrenalectomized rats. The adrenalectomized rats were given saline for 5–7 days following adrenalectomy, and sacrificed after an additional 6–8 days without saline. Electrocardiograms, growth curves, heart-body weight ratios and nitrogen content of heart tissue were recorded for all control and experimental animals. Strength-duration curves, refractory periods, and developed and passive length-tension diagrams of heart columns from adrenalectomized animals did not differ statistically from normal, but resting respiratory rates were significantly increased. Results indicate that adrenal insufficiency lowers the in vitro efficiency of cardiac function by greatly increasing the metabolism of the myocardium without altering its contractility.
Sodium retention by rats bearing the Walker carcinosarcoma 256
Authors: Toal Jane Nicolet , Millar Florence K. , Brooks Robin H. , White Julius
Published: December 2017

Sprague-Dawley rats bearing the Walker tumor and remaining in nitrogen balance, during the later stages of tumor growth invariably excreted less than normal amounts of their Na and Cl intake. Potassium excretion during tumor growth remained essentially unaltered. Sodium retention occurred when the tumor was 10% or more of the body weight. Extirpation of the tumor from a rat during a period of Na retention resulted in a prompt return of the Na and Cl excretions to normal. Tumor-bearing rats that have retained Na for prolonged periods have hypertrophied adrenals with enlarged sinusoids; and such rats ingesting a basal diet containing 20% casein also show zona glomerulosa enlargement. Balance studies showed that the amount of Na found in the tumor accounted for almost all of the total Na retained during the study. Changes in concentration of Na, Cl, K, N and water in the carcasses of tumor-bearing rats were similar to concentration changes reported for undernourished rats (Na, Cl and N increased, K and water decreased).
Estimation of material balance of totally fasted rats by doubly labeled water
Authors: Lifson Nathan , Lee J. S.
Published: December 2017

A test has been carried out of the possibility of estimating, with the aid of D2O18, the CO2 and water output of six rats in a severely nonsteady state, that resulting from complete deprivation of food and water. The data used for the estimation were a) isotopic concentrations in initial and final blood water, b) initial and final body weights and c) final percentage body water. In addition, O2 consumption was calculated from the CO2 output and the R.Q. The isotopically computed values were compared with those observed in an open-circuit metabolic train which were taken to be correct. Despite a number of simplifying assumptions, the average errors under the conditions of the test were 4, 3 and 5% for CO2 output, water output and O2 consumption, respectively.
Active chloride transport during intestinal secretion
Authors: Tidball C. S.
Published: December 2017

Characteristically water and chloride ion are absorbed from isotonic saline solutions placed in the in situ jejunal loop of the anesthetized dog. The direction of the water and chloride movement can be reversed by the administration of a cholinergic drug or by the addition of substituted phenols to the isotonic solution bathing the mucosal surface. During such secretion the movement of chloride occurs against a concentration gradient. The transmural electrical potential difference indicates that the lumen is negative with respect to the serosal surface during secretion; thus chloride is also moving against an electrical potential gradient. The calculated concentration of chloride in the fluid moving through the membrane during secretion is higher than the chloride concentration in extracellular fluid which indicates that solvent drag is not responsible for the chloride movement. Therefore active transport of chloride occurs during intestinal secretion.
Role of catecholamine release in morphine hyperglycemia
Authors: Vassalle Mario
Published: December 2017

The mechanism of morphine hyperglycemia was studied in intact and chronically adrenalectomized dogs. Adrenergic blocking agents were used to provide a further analysis of the hyperglycemic action of morphine. Venous hematocrit and plasma specific gravity were measured on the assumption that catecholamines released by morphine could elicit a contraction of the spleen. Morphine administration caused a rise in both sugar and hematocrit; after adrenalectomy, blood sugar and hematocrit showed a much smaller increase. Morphine hyperglycemia was antagonized by dihydroergotamine and dichloroisoproterenol but not by Dibenamine. Since this is the pattern of epinephrine hyperglycemia it was concluded that morphine hyperglycemia is mediated by the release of catecholamines, mainly from the adrenal medulla. Atropine and Artane failed to counteract morphine hyperglycemia. Thus these experiments, as far as the blood sugar is concerned, do not favor the hypothesis that morphine acts through an anticholinesterase mechanism.