bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue distribution of electrolytes, Ca47, and Mg28 in acute hypercalcemia
Authors: Wallach Stanley , Bellavia Josephine V. , Schorr Jack , Reizenstein David L.
Published: December 2017

The in vivo effects of acute hypercalcemia on plasma and tissue distribution of electrolytes, radiocalcium, and radiomagnesium were studied in acutely renal-ligated dogs. Hypercalcemia abruptly increased plasma potassium and phosphorus concentrations but had no significant effect on plasma concentrations of other electrolytes. Skeletal muscle and myocardial sodium decreased 15%, skeletal muscle chloride decreased 22%, and pancreatic and aortic potassium increased 12%. Tissue phosphorus concentrations were unchanged. Total cellular calcium increased 40–70% in liver, myocardium, nerve, and aorta, was suggestively increased in skeletal muscle, and was unchanged in pancreas, brain, and bone. Exchangeable cellular calcium increased 35–75% in liver, skeletal muscle, myocardium, nerve, and aorta and was unchanged in pancreas and brain. Bone exchangeable calcium increased 260%. Exchangeable cellular magnesium of skeletal muscle and pancreas decreased 28% but total cellular magnesium concentrations were unaltered. The changes noted in individual tissues were reflected by 50% increases in exchanged able body and over-all tissue calcium pools and in unchanged exchangeable body and over-all tissue magnesium pools. No significant changes in fractional rates of calcium and magnesium turnover occurred. These data indicate that hypercalcemia causes 1) cellular accumulation of calcium by many but not all tissues, 2) inhibition of magnesium uptake by certain cells, and 3) changes in tissue sodium and potassium distribution which are compatible with known in vitro inhibitory effects of calcium on cellular electrolyte transport.
Electrolyte changes in rat stomachs following instillation of acid solutions
Authors: Lindner Arthur E.
Published: December 2017

An isotonic solution containing 55 mEq/liter hydrogen, 100 mEq/liter sodium, and 155 mEq/liter chloride was instilled into pylorus- and cardia-ligated stomachs of intact and vagotomized anesthetized rats for 2-hr periods. Two patterns of change were observed in the solution. In all vagotomized rats and some intact animals, there was a modest increase in volume with reduction in acidity, decrease in chloride concentration and osmolality, rise in sodium concentration, and increase in potassium concentration. In some animals with intact vagi there was a larger increase in volume, an increase in acidity, rise in chloride concentration and osmolality, fall in sodium concentration, and increase in potassium concentration. Changes are compared with those previously observed in human stomachs and differences interpreted in terms of possible persistent vagal activity in the rat. Appreciable volumes of fluid were added to the gastric contents. Net gain of sodium greatly exceeded net loss of hydrogen during most periods. Both dilution-neutralization and diffusion mechanisms may operate when there is reduction in acidity of instilled acid solutions.
Responses elicited from orbital cortex of cats: overt activity and related pathways
Authors: Ward James W. , Back James B.
Published: December 2017

Electrical stimulation of the cortex adjacent to the presylvian sulcus in unanesthetized cats through implanted electrodes yields inhibition of walking but not of tone or other activities. Alerting appears to be the common denominator for elicited responses which include alteration in respiration, sniffing, licking, chewing, staring, skin hypersenstivity, alerting, tail wagging, and the like. Results suggest that this cortical area functions in part in claboration of alerting and/or protective behavior initiated by a wide variety of sensory modalities (more than the "oral senses"). Olfactory bulb stimulation did not yield the alerting pattern. Pathways were traced by evoked potentials from the fixed points of the known "function" described above. Localized activity initiated through different fixed electrodes was recorded in the internal capsule, basis pedunculi, pyramid, substantia nigra, reticular formation of mesencephalon and medulla, caudate nucleus, thalamus except anterior nucleus, hypothalamus except mamillary bodies, anterior sylvian and ectosylvian gyri, cingulate gyrus, and the cerebellum. Projection via internal capsule to the reticular formation seems to be the most likely route for inhibition.
Paper chromatographic identification of angiotensins
Authors: Wisenbaugh Paul E. , Wills Noah E. , Hill Robert W.
Published: December 2017

The separation of angiotensin I and angiotensin II by paper chromatography using an acid NaCl solution is described. When the pressor material recovered from the blood of dogs infused with renin was analyzed by this method, significant quantities of angiotensin I as well as angiotensin II were found in those infused at rates above 1 Goldblatt U/min. At infusion rates below 1 U/min, only angiotensin II was present. In each of six dogs with malignant experimental renal hypertension, significant increases in circulating pressor material were found 48 hr or more after renal artery constriction. Analysis of the material recovered from the blood of five of these dogs revealed only angiotensin II in four instances, and a mixture of angiotensin I and II in one instance.
Effect of temperature on metabolism of glucose in vitro
Authors: Fuhrman Geraldine J. , Fuhrman Frederick A.
Published: December 2017

We recently showed that hypothermic rats fail to remove glucose from the extracellular phase. This information led to these studies on the uptake of glucose at low temperatures by rat diaphragm and red blood cells and its phosphorylation by hexokinase. It is shown here that rat diaphragm and red blood cells utilize glucose at all temperatures from 1 to 38 C. Both processes follow the Arrhenius equation and give µ equal to 18,000 and 21,900, respectively. The velocities of the phosphorylation of glucose by hexokinase from yeast and from rat muscle both yield straight lines on an Arrhenius plot with µ equal to 13,300 and 14,900. The temperature coefficient of the velocity of action of hexokinase is consistent with the effects of temperature on other enzymes. Penetration of glucose into cells at low temperatures apparently equals or exceeds the rate of phosphorylation. Thus the abnormal metabolism of glucose in hypothermia is not caused by failure of glucose to penetrate cells, and there is no unusual sensitivity of hexokinase to changes in temperature.
Importance of noradrenaline in cold adaptation
Authors: Leblanc Jacques , Pouliot Marcel
Published: December 2017

Noradrenaline (300 µg/kg) was injected daily for 45 days in a group of 15 rats. At the end of this period O2 consumption and rectal temperature responses to noradrenaline (200 µg/kg) were measured at 30 C in these animals as well as in cold-acclimated and control groups. Noradrenaline-treated and cold-acclimated animals have a larger O2 and rectal temperature increase than the control. At –20 C the noradrenaline-treated and cold-adapted rats maintained a higher rectal temperature and survived longer than the control group. These results indicate that repeated injections of noradrenaline to animals at room temperature can produce some cold acclimation and suggest that noradrenaline may be of importance in acquiring acclimation in rats exposed to cold.
Effects of fibrinolytic agents and heparin on blood coagulation in dogs
Authors: Lewis Jessica H. , Shirakawa Mitsuru
Published: December 2017

In vitro experiments demonstrated that incubation of dog plasma with Thrombolysin or Actase caused marked falls in factors I, VIII, and IX, a moderate fall in factor V, and the appearance of a heat-labile clot inhibitor. Incubation of dog plasma with streptokinase (SK), staphylokinase, trypsin, bromelain, or dog fibrinolysin in amounts similar to those used in in vivo studies had little effect on these coagulation factors. If the streptokinase concentration were increased 10- to 15-fold results similar to those found with Thrombolysin were observed. Intravenous infusions of Thrombolysin or Actase resulted in marked depressions of factors I, VIII, and V, minimal depressions of factors II, VII, and IX, and the development of a clot inhibitor. Seven dogs who received SK showed no coagulation changes, while three showed moderate fibrinogenolysis and inhibitor formation.
Influence of water temperature on heart rate and rectal temperature of swimming rats
Authors: Baker Mary Ann , Horvath Steven M.
Published: December 2017

The heart rate and rectal temperature of 12 adult male hooded rats were studied during 10-min swims in water of 37, 20, and 42 C. Both the heart rate and the rectal temperature stabilized in water of 37 C, suggesting that swimming in thermoneutral water is a submaximal exercise for rats. In water of 20 C, rectal temperature and heart rate of swimming animals fell exponentially to 28 C and 251 beats/min, respectively. The relationship of heart rate to rectal temperature in these swimming, cooling animals was not different from that reported in the literature for unanesthetized, inactive, hypothermic rats. It appeared that exercise had no effect on the heart rate of rats when the body temperature was dropping. In water of 42 C the rectal temperature rose exponentially to 42.2 C. The heart rate rose to 521 beats/min at the 8th min of swimming and remained stable thereafter. It is suggested that inadequate cardiac output resulting from severe changes in body temperature may be one factor which limits swimming capacity of small animals in hot and cold water.
Esophagus in rumination
Authors: Winship Daniel H. , Zboralske F. Frank , Weber William N. , Soergel Konrad H.
Published: December 2017

Esophageal motility studies of deglutition and rumination were performed in two sheep, two goats, and one calf. The esophageal motor response to balloon distention was investigated in the two sheep. Deglutition and rumination were studied cinefluorographically in the two sheep and one goat. All animals had a ruminoesophageal pressure difference of from 3 to 8 mm Hg, but none exhibited an inferior esophageal sphincter. Primary peristalsis progressed at a rate of 23.5–27.5 cm/sec. Secondary peristalsis was present only in the distal 10 cm of the esophagus, and only distal to the distending balloon. Rumination, unrelated to respiration, produced an initial pressure plateau interpreted as ruminoesophageal reflux, terminating in a contraction wave which was frequently of retrograde peristaltic character in the sheep and calf, traveling at rates averaging 42.5 and 53.8 cm/ sec in the sheep, 112.5 cm/sec in the calf. Rumination begins with ruminoesophageal reflux, facilitated by the ruminoesophageal pressure difference and absence of the inferior esophageal sphincter. The bolus is frequently carried toward the mouth by retrograde peristalsis.
Absorption and excretion of Cu64-labeled copper by the rat
Authors: Owen Charles A.
Published: December 2017

Varying doses of Cu64-labeled cupric acetate were given orally or intravenously to adult male rats. The urinary and fecal excretion of Cu64 was measured in intact rats and in rats with obstruction of the common duct. In addition, the biliary Cu64 was assayed in rats with biliary fistula. Only about half to two-thirds of doses up to 1 µg of copper were absorbed; the site of absorption seemed to be the upper portion of the small intestine. With larger doses, the percentage absorbed fell, but the absolute amount increased. Much less copper was excreted in the feces when the rat had a biliary fistula, the difference being accounted for by the biliary Cu64. Fecal excretion was not prevented by duodenostomy below the pancreatic and biliary ducts and therefore presumably reflects excretion through the gut mucosa. Significantly more copper was excreted in the bile and in the urine when the Cu64 was given intravenously. Very little of the biliary Cu64 was absorbed from the gut of intact rats when it was given by stomach tube.
Metabolic influences on enzymes of glycogen synthesis and breakdown in adipose tissue
Authors: Gutman Alisa , Shafrir Eleazar
Published: December 2017

Rat adipose tissue from different body sites was shown to contain uridine diphosphoglucose (UDPG)-transglucosylase activity, which on the basis of protein content was comparable to or higher than that reported for muscle or liver. In epididymal adipose tissue, the activity of UDPG-glycogen transglucosylase and phosphorylase, as well as the content of glycogen per wet weight, decreased with increasing age of the animals in parallel with the decrease of tissue protein content. On prolonged fast the activity of UDPG-glycogen transglucosylase and phosphorylase per milligram protein dropped by 25–50% of the control value. On refeeding, the extent of changes was variable but, in general, at 24 hr control or higher levels of activity were reached and at 48 hr the activities were elevated. The ratio of glucose 6-phosphate independent activity of UDPG-glycogen transglucosylase to total activity was not affected by fasting and refeeding or by the administration of glucose with insulin. In adrenalectomized rats, with high adipose tissue glycogen, no change in UDPG-glycogen transglucosylase was found, whereas the levels of phosphorylase were elevated. Epinephrine in vivo and in vitro did not affect the activity of UDPG-glycogen transglucosylase of adipose tissue.
Effect of lactic acid on plasma free fatty acids in pancreatectomized dogs
Authors: Miller H. I. , Issekutz B. , Paul P. , Rodahl K.
Published: December 2017

Sodium lactate infusions into unanesthetized pancreatectomized dogs, with indwelling arterial and venous catheters, markedly decreased the plasma free fatty acid (FFA) level. Infusions of palmitate-1-C14 at constant rates showed that the rate of release of FFA was considerably reduced by the lactate. There was an inverse correlation between the logarithm of the plasma FFA concentrations and the logarithm of the blood lactate levels. Glucose infusion alone had no significant effect on the plasma FFA of the pancreatectomized dog. When both lactate and glucose were infused into the pancreatectomized dog, the plasma FFA was inversely correlated with the blood lactate level but not with the blood sugar. When the plasma FFA was elevated in normal dogs by norepinephrine infusion, the FFA-lowering effect of sodium lactate was not prevented. Neither acetylcholine nor nitroglycerine infusions had any marked effect on the plasma FFA. It is concluded that lactic acid has a direct effect on the release of FFA which does not require the presence of insulin and is independent of the blood glucose concentration.
CO2 formed from endogenous and exogenous substrates in perfused rat heart
Authors: Shipp Joseph C. , Matos Otsenre E. , Knizley Homer , Crevasse Lamar E.
Published: December 2017

Measurements of total CO2 and C14O2 production by the isolated, perfused rat heart showed the extent of respiration dependent on endogenous and exogenous substrates. Glucose, acetate, and palmitate, but not glutamic acid or leucine, contributed appreciably to respiration. With optimal glucose and palmitate oxidation endogenous substrates accounted for over half of CO2. Endogenous substrates were adequate to maintain respiration for 30 but not for 60 min. Dependence of respiration on lipids was suggested by the similarity of metabolic CO2 in glycogen-depleted hearts perfused with no added substrate, with palmitate-1-C14, and with glucose-U-C14 plus palmitate. A reduction in C14O2 and in total CO2 formation with glucose-U-C14 in the presence of palmitate provided further support for the preferential oxidation of fatty acids. The Vo2, estimated from the total and C14O2, and an assumed respiratory quotient, indicated adequate oxygenation of the heart in the closed recirculated system. The necessity of maintaining an adequate coronary artery flow rate was indicated by an altered pattern of cell metabolism in hearts with reduced coronary perfusion.
Series elastic and contractile elements in heart muscle: changes in muscle length
Authors: Sonnenblick Edmund H.
Published: December 2017

Isometric force generation, the result of the interaction of an actively shortening contractile element (CE) with a passive series elastic component (SE), has been analyzed in heart muscle using the cat papillary muscle. The stiffness of the SE (Δ load/Δ extension or d p/d l) was shown to be a linear function of developed force of contraction or load ( P). The load-extension curve of the SE was thus exponential in form, the SE being stretched an amount equivalent to 8–10% of initial muscle length during the development of maximum isometric force (600 g/cm2). The load-extension curve of the SE was also obtained from the curve relating initial velocity of shortening to time after stimulation. This latter relation and the linear relation of SE stiffness to force were found to be independent of initial muscle length. These results were interpreted to suggest that increases in muscle length bring about an increase in the number of series elastic components as well as contractile elements arranged in parallel. The series elastic component thus cannot be relegated entirely to external attachments of the muscle (e.g., tendon), but must be closely associated with the contractile element system itself.
Preparation of vesicular relaxing factor from bovine heart tissue
Authors: Inesi Giuseppe , Ebashi Setsuro , Watanabe Shizuo
Published: December 2017

A particulated fraction, consisting mainly of protein and phospholipid, was prepared from bovine heart muscle by differential centrifugation. This microsomal suspension was found to inhibit superprecipitation of myosin B and to have a strong calcium-binding capacity. Although the preparation appeared to be very labile, a constant degree of activity was obtained by adding α-tocopherol before the homogenization of cardiac tissue. Evidence was gained for an interaction of calcium ions with synthetic lecithin in water suspensions. However, this interaction was competitively inhibited by the presence of magnesium and ATP, which are required cofactors for calcium binding by microsomes. It is proposed that in cardiac muscle, sarcoplasmic reticulum plays essentially the same role as in skeletal muscle.
Cardiac output in hibernating ground squirrels
Authors: Popovic Vojin
Published: December 2017

After chronic cannulation of the aorta and right ventricle with polyethylene tubes, ground squirrels re-entered hibernation and were used for cardiac output determinations (Fick principle). The cardiac output of a 210- to 220-g hibernating ground squirrel at a body temperature of 7 C was about 1.0 ml/min, about 65 times smaller than in the active state. A similar decrease occurred in the oxygen consumption of the hibernating animals. The arteriovenous difference of oxygen contents of the blood was unchanged in hibernation despite somewhat decreased oxygen content of arterial blood. The hematocrit ratio was 57 vol % in euthermic ground squirrels and only 40 in hibernating animals.
Hematology of the bottlenose dolphin (Tursiops truncatus)
Authors: Medway William , Geraci Joseph R.
Published: December 2017

The hematology of six bottlenose dolphins, kept in an aquarium filled with simulated sea water, has been studied. Blood samples were easily collected from a branch of the brachial vessels. With the exceptions of the low total red cell count, larger mean corpuscular volume, and the high normal eosinophil count, the other hematological parameters are comparable to those of the common domestic animals.
Learning and extinction during chemically induced disturbance of hippocampal functions
Authors: Grossman S. P. , Mountford H.
Published: December 2017

Potassium chloride was introduced into the hippocampi of rats to study the effects of a persisting but reversible disturbance of hippocampal functions on the acquisition, performance, and extinction of a black-white discrimination habit in a T maze apparatus. Acquisition and retention, as measured by the percentage of correct choices, were not affected by the disruption of hippocampal functions. However, an analysis of the temporal parameters of the discrimination response (start, running, choice, and total response speed) demonstrated significant performance deficits during acquisition as well as at the asymptote of performance. The correct choice as well as the latency measures reflected this impairment during extinction. The results are interpreted to suggest that an interference with hippocampal functions may affect performance variables such as motivation rather than associative mechanisms specifically related to acquisition or retention.
Effect of ketone bodies on cardiac metabolism
Authors: Bassenge E. , Wendt V. E. , Schollmeyer P. , Blümchen G. , Gudbjarnason S. , Bing R. J.
Published: December 2017

The effect of acetoacetate infusion on myocardial metabolism was studied in 13 dogs at varying concentrations of acetoacetate. Acetoacetate was extracted by the myocardium at arterial levels of from 1 to 54 mg/100 ml. At arterial levels of above 60 mg/100 ml, extraction of acetoacetate by the heart was very small. Considerable amounts of the infused acetoacetate were reduced to beta-hydroxybutyrate. Acetoacetate inhibited the utilization of free fatty acids by the heart, resulting in a rise in the respiratory quotient of the heart. An increase in the myocardial extraction of lactate occurred at arterial acetoacetate levels of below 34 mg/100 ml. Between 34 and 80 mg/100 ml of acetoacetate levels, myocardial lactate extraction declined; the ketone became the preferred fuel of the myocardium at arterial acetoacetate levels between 34 and 54 mg/100 ml. Arterial glucose levels fell gradually during the experiment, leading to severe hypoglycemia. The negative myocardial balance of pyruvate significantly increased throughout the experiment. Coronary blood flow, heart rate, left ventricular pressure, myocardial contractility, and EKG were not affected significantly by arterial acetoacetate levels ranging from 1 to 80 mg/100 ml.
Iron transport after injection of endotoxin in rats
Authors: Kampschmidt Ralph F. , Upchurch Herbert F. , Johnson Herman L.
Published: December 2017

The injection of Escherichia coli lipopolysaccharide produces a rapid decline in plasma iron concentration of normal rats. To understand the mechanism of this decrease, combinations of acetylphenylhydrazine and endotoxins were given and measurements of rates of iron transfer from Fe59-labeled damaged red blood cells to the plasma were made. Shortly after giving endotoxin there was an inhibition of the movement of iron from catabolized red blood cells to the plasma transferrin. This inhibition can be partially overcome by increasing the number of erythrocytes which are phagocytized in a given period of time. The major reason for the decrease in plasma iron after an injection of endotoxin was found to be an inhibited reutilization of iron from recently destroyed erythrocytes.
Active sodium transport in toad bladder despite removal of serosal potassium
Authors: Essig Alvin
Published: December 2017

Previous studies have demonstrated that removal of potassium from sodium-Ringer solution bathing the serosal surface of the toad badder depressed net sodium transport to some 5% of control value, whereas with choline-Ringer solution as serosal medium removal of serosal potassium depressed net sodium transport only to some 55% of control value. Although transport is down a chemical potential gradient in the latter situation, it appears to be an active process, for it is depressed by anaerobiosis, and persists against an electrochemical potential gradient. The data suggest that the concentration of potassium at the serosal aspect of the sodium pump is not in itself the rate-determining factor for active sodium transport following removal of serosal potassium.
Microcirculatory effects of whole-body X-irradiation and radiomimetic procedures
Authors: Zweifach Benjamin W. , Kivy-Rosenberg Evelyn
Published: December 2017

Whole-body X-irradiation (WBR) was administered to young adult, unanesthetized rats. Terminal vascular beds of the exteriorized mesocecum of these rats (most of which had received relatively high doses of X-rays) were observed (under anesthesia) at selected periods between 1 hr and 48 days postirradiation. Thirteen experimental categories were utilized to determine the status of reactivity and of the microvascular barrier. These included topical application of epinephrine, norepinephrine, histamine, and Versene; and injection of heparin, cortisone, nitrogen mustard, bacterial endotoxin, and carbon. Results indicate that by the 3rd–4th day after WBR, response of terminal arterioles and precapillaries to epinephrine and norepinephrine are exaggerated and by the 2nd week, activity is up tenfold over threshold levels. With regard to venular and capillary walls, Versene had a dramatic disruptive effect. The character of the lesion suggests that it is due to an undermining and weakening of the basement membrane, and/or forces which hold the endothelial cells together. There is no evidence, however, that the endothelial cell has been damaged.
Enhancement of fibrinolysis in the dog by injection of vasoactive drugs
Authors: Holemans Rudolf
Published: December 2017

Intravenous injection of epinephrine into the dog produces an increase in fibrinolytic activity of plasma euglobulins. This increase appears to be unrelated to the following epinephrine-induced effects: splenic contraction, stimulation of the lymph circulation, increase in blood glucose, lactic acid, or free fatty acids. A specific involvement of either alpha or beta adrenotropic receptors is ruled out since norepinephrine and isopropylnorepinephrine are equally effective in enhancing fibrinolysis. Intravenous injection of each of a number of vasoactive drugs with different modes of action, and with either hypertensive or hypotensive properties, induces an increase in fibrinolytic activity. Hence, it appears that there is a direct relationship between appearance of increased fibrinolytic activity and vasoactive changes. For all the drugs tested except methoxamine, the maximal fibrinolytic effect is present 5 min after the injection and in general the fibrinolytic activity returns to the preinjection level within 30 min. Repeated injections of a powerful inducer of increased fibrinolytic activity, such as histamine, results in a progressive decrease of the fibrinolytic response.
Kinetics of intestinal active transport of five neutral amino acids
Authors: Matthews D. M. , Laster Leonard
Published: December 2017

Rates of transport against a concentration gradient by everted segments of hamster small intestine were determined for five monoaminomonocarboxylic acids. Values varied considerably from animal to animal. A graph of reciprocal of transport rate as a function of reciprocal of initial amino acid concentration revealed a linear relationship for each amino acid. Values for Kt, the concentration at which half-maximal transport is observed, diminished with increasing length of side chain for glycine, l-alanine, l-valine, and l-leucine. The Kt for α-aminoisobutyric acid was much higher than the others. Values for Vmax, the apparent limiting transport rate, decreased as chain length increased. With increasing initial amino acid concentration transport rate rose to a maximum and then declined. At concentrations producing this decline no gross mucosal damage was noted. The apparent inhibitory effect of these high concentrations was not a permanent one.
Active transport of quaternary ammonium compounds by the choroid plexus in vitro
Authors: Tochino Yoshihiro , Schanker Lewis S.
Published: December 2017

The quaternary ammonium compounds, hexamethonium, decamethonium, and N1-methylnicotinamide (NMN) are taken up by the rabbit choroid plexus in vitro (Krebs-Ringer phosphate glucose solution, pH 7.4, 37 C, oxygen) by a process showing all the characteristics of active transport. Uptake against a concentration gradient occurs by a saturable process that is inhibited by low temperature, by anaerobic conditions, and by low concentrations of ouabain, reserpine, and certain metabolic inhibitors. Decamethonium and NMN act as competitive inhibitors of hexamethonium uptake, suggesting that the three cations share a common transport process. Hexamethonium uptake is dependent on levels of Na, K, Mg, and phosphate in the incubation medium. Hexamethonium and decamethonium, but not NMN, are bound to homogenates of choroid plexus. The characteristics of the binding are such that binding would not account for the bulk of drug accumulation seen in the intact tissue. High concentrations of p-aminohippurate do not inhibit the uptake of hexamethonium. No evidence could be obtained for active uptake of hexamethonium by subcellular particles of plexus homogenates. The transport process for quaternary ammonium compounds appears to be present in the choroid plexus of the dog, cat, and guinea pig as well as in that of the rabbit.
Variation of cerebral cortex fluid spaces in vivo as a function of species brain size
Authors: Bourke Robert S. , Greenberg Edward S. , Tower Donald B.
Published: December 2017

Sizes of cerebral cortex fluid spaces accessible to chloride, thiocyanate-C14, sucrose-C14, and inulin-C14 were investigated in nine mammalian species. Indicator solutes were injected intracisternally, and after suitable intervals subarachnoid CSF and subadjacent cerebral cortex were sampled. Factors of site, time, and reproducibility of sampling were studied in detail. Despite influences of nonhomogeneous distribution in CSF of injected solutes and other factors on space measurements, appropriate attention to experimental conditions provided consistent, reproducible results. For a given species, there was identity of cortical chloride and thiocyanate spaces and identity of sucrose and inulin spaces, with the latter slightly but significantly smaller than the former. From smaller to larger species, all spaces exhibited parallel, significant increases (e.g., average sucrose-inulin spaces for guinea pig: 20.8%; cat: 27.4%; chimpanzee: 39.4%), varying as a function of the logarithm of the average, species brain weight. Findings are discussed relevant to CSF solute distribution and efflux and to electron microscope observations, glial and extra-cellular distribution of solutes, and abnormal conditions such as edema following circulatory arrest.
Quantitative synthesis of head and foreleg arterial pulses in the dog
Authors: Remington John W.
Published: December 2017

The carotid and the subclavian arterial-systems were treated as though composed of a series of homogeneous distensible tubes joined in series or in parallel. With minor corrections, the contour of the aortic arch pulse was taken as that of a single transient incident wave entering the proximal end of these systems. Pulse height changes were localized to the junctions between coupled tubes of dissimilar wave impedance values. The amount of pressure change at these junctions was calculated by comparing arterial pulses recorded from various sites in these systems with the aortic pulse. An attempt was made to keep a strict accounting of all reflected waves arising either from the junction points or from peripheral drainage beds. The pulse constructions provided evidence for appreciable junctional positive reflections which alter the contour of the peripheral pulses. Because returning reflected waves from these sites were reflected negatively at each junction, their amplitude on entering the aorta was relatively small. The good-to-excellent reconstructions of the actual pulse contours suggest that the method of analysis used has promise, and that the basic assumptions on which the calculation of reflection coefficients was based did not impose errors of critical importance.
Role of semicircular canals in positional alcohol nystagmus
Authors: Money K. E. , Johnson W. H. , Corlett B. M. A.
Published: December 2017

Following unilateral labyrinthectomy or inactivation of one horizontal semicircular canal in cats, a horizontal positional nystagmus was observed when the cat, after ingesting alcohol, was held with the head up or with the head down. This nystagmus was toward the operated ear in the head-up position and away from the operated ear in the head-down position. It disappeared following inactivation of the horizontal canal of the other ear. In cats with both horizontal canals discretely inactivated, there was no horizontal alcohol nystagmus in any position, but the vertical and rotary components of positional alcohol nystagmus were still present. It was concluded that positional alcohol nystagmus is initiated by the action of gravity on receptors of the semicircular canals. No conclusion could be drawn concerning the site or mechanism of the action of alcohol.
Renal tubular reabsorption of trace alkaline earths compared with calcium
Authors: Rahill W. Joseph , Walser Mackenzie
Published: December 2017

Simultaneous clearances of inulin, calcium, and either Be7, Ba140, or Ra226, given by constant infusion, were measured in salt-depleted dogs or dogs undergoing mild saline, mannitol, or sulfate diuresis. Urine-to-plasma ratios of all three cations less than 0.5 were noted, suggesting that all can be actively reabsorbed. Clearances of barium and radium were correlated with calcium clearance, but the clearance of beryllium was unpredictable. Protein binding of beryllium was shown to be of the same order of magnitude as other alkaline earths when errors due to adsorption of Be7 onto containers were minimized. Protein binding of barium averaged 54%. The excreted-to-filtered ratio for barium was a constant power (.54) of the ratio for calcium. The data do not exclude the possibility that these cations are reabsorbed by a common transport mechanism with calcium.
Role of metabolism in K-induced tension changes in guinea pig taenia coli
Authors: Pfaffman M. , Urakawa N. , Holland W. C.
Published: December 2017

Further insight into the underlying mechanism(s) of the K-induced phasic and tonic contractions of the taenia coli of the guinea pig was obtained by examining the effects of various metabolic intermediates, inhibitors of metabolism and active transport, on these responses. Evidence is presented to support the thesis that the tonic response is dependent on the aerobic breakdown of carbohydrates and is abolished by substrate removal, a decrease of temperature, DNP, lithium, and ouabain. These same factors have little or no effect on the phasic response. From the evidence presented, it is concluded that the phasic response is a passive process, whereas the tonic contracture is an active one depending on metabolism and possibly linked to active Na transport.
Thoracic duct lymph and lymphocytes during primary hypoxia and rebound
Authors: Evans D. A. , Garnett R. A. F. , Yoffey J. M.
Published: December 2017

Thoracic duct lymph flow and lymphocytes were first studied in 18 normal guinea pigs. Similar studies were then made on a) 25 guinea pigs placed in a decompression chamber at a simulated altitude of 14,000 ft for times ranging from 1 to 5 days, this being the period of "primary hypoxia" during which erythropoiesis is stimulated and polycythemia develops, and b) 25 guinea pigs exposed to primary hypoxia for 5 days, then kept in room air for times ranging from 1 to 5 days, this period of posthypoxic polycythemia being known as "rebound." By the end of rebound the polycythemia had almost disappeared. The flow of thoracic duct lymph increased significantly from a control level of 0.86 ± 0.21 ml/hr to 1.23 ± 0.1 ml/hr by the 5th day of primary hypoxia, and to a peak of 1.89 ± 0.23 ml/hr by the 3rd day of rebound, falling slightly to 1.56 ± 0.14 ml/hr by the 5th day of rebound, when it was still markedly above control level. The total cell content of the lymph also rose significantly, from 34.5 ± 10.3 x 106 lymphocytes/hr in the control animal to 59.1 ± 8.9 x 106 /hr on the 5th day of primary hypoxia, and to a peak of 93.8 ± 23.0 x 106 on the 3rd day of rebound.
Subcellular site of porphyrin biosynthesis in nucleated erythrocytes
Authors: Sardesai Vishwanath M. , Doehr Sally A. , Orten James M.
Published: December 2017

The activity of hemolysates, prepared by several different methods from nucleated (chicken) erythrocytes, and of their subcellular fractions in forming porphyrins from glycine plus acetate or succinate or from δ-aminolevulinic acid (ALA) was studied. In general, hemolysates were less active than intact cells in porphyrin biosynthesis from glycine and acetate but were more active with ALA as the substrate. The supernatant fraction formed coproporphyrin from ALA but not from glycine and acetate. Protoporphyrin was not formed from either precursor by the supernatant fraction. The particulate fraction alone was devoid of porphyrin-forming activity, and also of ALA- and porphobilinogen- (PBG) forming activity. The combined particulate-supernatant fractions, however, synthesized both copro- and protoporphyrins from either glycine and acetate or ALA, but of course more from the latter. Dialysis or heating to 60 C destroyed the activity of the supernatant. These results indicate that "compartmentation" of porphyrin biosynthesis occurs in the nucleated erythrocyte much as in the liver cell, the step from ALA to coproporphyrinogen being carried out in the soluble, "nonparticulate" cellular fraction and the remaining steps in the "particulate" fraction.
Bulbar gustatory responses to anterior and to posterior tongue stimulation in the rat
Authors: Halpern Bruce P. , Nelson Linda M.
Published: December 2017

Amplitudes of neural responses in the nucleus of the fasciculus solitarius to stimulation of the tongue with quinine hydrochloride were analyzed using the response to NaCl as a reference standard. Three distinguishable areas were observed within the gustatory response zone of the nucleus. One area, responsive only to stimulation of the anterior region of the tongue, was at the anterolateral limit of the active zone. A second area, caudal and medial to the first, responded to both anterior and posterior tongue-region stimulation, the latter region yielding larger responses. Medial to both of the other areas was a third, highly responsive area, which responded only to posterior tongue-region stimulation.
Inhibition of absorption of d-xylose by phlorizin in the anesthetized rat
Authors: Salem Antoun A. , Cocco Arthur E. , Hendrix Thomas R.
Published: December 2017

The effect of phlorizin on d-xylose absorption was studied in jejunal and ileal segments of anesthetized rats at different concentrations of the sugar. There was an inhibition of d-xylose absorption (79–92%) at sugar concentrations of 2.5 and 5.0 g/liter. A significant but less striking inhibition was demonstrated at a sugar concentration of 10 g/liter, but no significant inhibition could be demonstrated at a concentration of 50 g/liter. It is postulated that a specific "phlorizin-sensitive" transport mechanism is involved in d-xylose absorption and is the major pathway for absorption at low sugar concentrations. As the sugar concentration increases this mechanism becomes saturated and the amount of sugar transported through it becomes constant, while the fraction transported through a "phlorizin-insensitive" mechanism becomes greater. This would explain why at a relatively high concentration of 50 g/liter no significant inhibition could be demonstrated.
Pressure studies of the ileocolonic junctional zone of dogs
Authors: Kelley Maurice L. , Gordon Elizabeth A. , DeWeese James A.
Published: December 2017

This investigation was undertaken to define the pressure profile of the canine ileocolonic junctional segment and to determine whether a zone of increased pressure exists between the ileum and colon. In four adult dogs, the area was made accessible by bringing ileal and colonic stomas to the abdominal wall. An open-tipped, water-filled polyethylene tube and miniature balloons, 5 x 10 and 7 x 7 mm, tied over identical tubes and connected to pressure transducers were withdrawn at 0.5-cm intervals from the colon into the ileum of the fasted, conscious animals. In many instances, a zone of elevated pressure was encountered. Mean pressures at the center of the junctional area by the open-tipped tube were 19.7 (sem ± 1.43) cm H2O above ambient, 5 x 10 mm balloon 37.7 (sem ± 2.16) and 7 x 7 mm balloon 47 (sem ± 1.73). Similar pressures were recorded at this site when units were withdrawn from ileum to colon. Length of the zone was usually 1 cm. Simultaneous cinefluorographic pressure studies showed that the zone of increased pressure was located in the cone-shaped configuration indicating the ileocolonic junction.
Action of epinephrine on muscle glucose uptake depending on Ca++ and phosphate
Authors: Ui Michio
Published: December 2017

Studies have been made of the involvement of inorganic phosphate (Pi) and Ca++ in the mechanism by which epinephrine-induced inhibition of muscle glucose utilization was abolished during either alkalosis in vivo or incubation of the isolated rat diaphragm in vitro at a higher pH level. An increase in the concentration of Pi in muscle tissues was closely associated with prevention of the inhibitory action of epinephrine on glucose uptake. The interrelationship of Ca++ and Pi in aqueous solutions, and the additional observations that glucose uptake by rat diaphragm was accelerated in anaerobiosis only in the absence of Ca++, indicate a significance of Ca++ in muscle glucose metabolism. Assay of hexokinase activity in cell-free muscle preparations revealed that the inhibition of the enzyme activity by glucose 6-phosphate was profoundly influenced by the presence of Ca++ and Pi and was dependent on the concentration of ATP. It is suggested that Ca++ may provide the primary point of influence of epinephrine on glucose metabolism of the muscle.
Selective effect of insulin on glucose-U-C14 metabolism in rabbit liver slices
Authors: Snyder Peter J. , Cahill George F.
Published: December 2017

Insulin increased by 39% the recovery of carbon-C14 from uniformly labeled glucose in glycogen in rabbit liver slices incubated in a high-potassium buffer, but did not affect the recovery of glucose carbon in CO2 or total lipid. Since the pathways to CO2 and lipid were not relatively more saturated than that to glycogen in livers incubated under conditions identical to those in which the insulin effect was observed, the insulin effect is assumed to be specific for glycogen synthesis. Insulin had no effect on glucokinase activity in incubated rabbit liver slices during the time observed (1 hr), nor on the recovery of labeled glucose as any of the measured metabolic products after incubation in Krebs-Ringer buffer.
Insensitivity of cultured chick heart cells to autonomic agents and tetrodotoxin
Authors: Sperelakis Nick , Lehmkuhl D.
Published: December 2017

Trypsin-dispersed cells from heart (ventricles) of 7- to 8-day chick embryos and 6-day posthatched chicks were cultured 2–15 days. The isolated single cells became attached to the bottom of the culture dish and reassembled into various monolayer communities; the cells of one community usually contracted synchronously. By means of a bridge circuit, one microelectrode was used for simultaneously passing current and recording membrane potentials. The following chemical agents were electrophysiologically inactive at or below the concentrations indicated (in g/ml): acetylcholine (1.1 x 10–4), epinephrine (2 x 10–4), norepinephrine (3 x 10–4), and tetrodotoxin (1.3 x 10–5). In contrast, 2–7 mm Ba++ (used as a control) was very effective in partially depolarizing the cells, initiating spontaneity, and increasing the frequency of action potentials. Thus, cultured chick ventricular cells, both pacemaker and nonpacemaker, are insensitive to the autonomic agents. The data also suggest that acetylcholine is not necessarily involved in the electrogenesis of pacemaker potentials. The lack of effect of tetrodotoxin is unexplained.
Screen filtration pressure and pulmonary hypertension
Authors: Hissen Wolfgang , Swank Roy L.
Published: December 2017

A series of experiments was devised to test the resistance to flow through the lungs of blood samples with different screen filtration pressures (SFP). The pulmonary artery and left atrial presures were measured in dogs rendered acutely hypotensive by rapid bleeding, and in others subjected to severe soft tissue trauma. Following acute hypotension the SFP always increased before and more markedly in the pulmonary artery than it did in femoral artery or vein blood. In other dogs similar measurements were made in normotensive dogs perfused with blood having a high screen filtration pressure. In each of these series of experiments the pulmonary artery pressure and difference between it and the left atrial pressure increased when the blood of the animal developed a high SFP (during hypotension and after trauma), or when high SFP blood was infused into the animal. It was suggested that the high SFP was due to adhesive and aggregated blood cells, especially platelets and leukocytes, and that these aggregates had occluded numerous blood conduits of the lungs.
Erythrokinetics in the horse
Authors: Marcilese N. A. , Figueiras H. D. , Valsecchi R. M. , Fraga A. H. , Camberos H. R. , Varela J. E.
Published: December 2017

Erythrokinetics in 34 adult horses of three different breeds was studied by means of Fe59 tracing technique. The differences observed between the mean erythrokinetic values of the Thoroughbred English race horses and the draft horses were statistically significant. The Thoroughbred showed a greater erythropoietic activity. The erythropoietic activity parallels the total red cell mass of the three breeds, being highest in the Thoroughbred, intermediate in the saddle horse, and lowest in the draft horse.
Bone metabolism and regulation of the blood calcium level in rats
Authors: Bronner Felix , Aubert J. -P.
Published: December 2017

Combined kinetic (Ca45) and balance (Ca40) studies of young male Sprague-Dawley rats placed on three different levels of calcium intakes (0.05, 0.5, 1.0% Ca) showed that the blood plasma calcium level, as determined by atomic absorption spectrophotometry, remained constant and invariant over a range of absorption from 4.5 to 83.4 mg Ca/day and that the pool, i.e., all the exchangeable calcium in the body, did not increase with increased absorption. Hence no direct regulatory role can be attributed to the size of the pool. Measurement of the calcium deposition and resorption rates in bone showed that the former changed only little with increasing absorption, whereas the latter decreased nearly linearly under the same conditions. Calcium resorption from bone therefore appears to play the major role in regulating the blood calcium level.
Effects of large intravenous electrolyte infusions on rat gastric secretion
Authors: Baume Peter E. , Meng H. C. , Law David H.
Published: December 2017

Gastric secretion was studied in pylorus-ligated rats following single large intravenous injections of electrolyte solutions of varying composition, volume, and tonicity. Single large injections of isotonic sodium chloride led to a volume-related increase in the volume and acid output of gastric secretion without any alteration in the acidity of the gastric juice. The tonicity of the injected fluid was a critical controlling factor and in one experiment marked alterations in tonicity exerted more effect on the subsequent secretory response than did simultaneous large alterations in the volume of fluid injected. The solute load per se was not as critical a factor as was the tonicity of the fluid containing it. It was shown that neither the sodium nor the chloride ion was specifically required in the injected fluid for production of this response and that injections of extremely anisotonic solutions caused profound gastric secretory depression. In view of these findings, it is suggested that care be taken to select appropriate control solutions for intravenous injection in experiments involving the pylorus-ligated rat.