bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebral free energy and viability: ATP in rats under nitrogen and iodoacetate with the effects of temperature
Authors: Samson Frederick E. , Balfour William M. , Dahl Nancy A.
Published: December 2017

The survival times and the cerebral ATP concentrations during anoxia have been determined. Rats were subjected to anoxia for a measured time, returned to air and survival determined. For ATP determinations, rats were frozen in liquid nitrogen following the anoxia, and the brain analyzed by the firefly luminescence method. The survival time (ST50) in anoxia is 63 seconds. During the first 20 seconds, the ATP remains at 2µM/gm; it then falls to 1.0 µM/gm at 65 seconds. When glycolysis is inhibited by sodium iodoacetate the ST50 decreases to 10 seconds; the ATP remains unchanged for 5 seconds and then decreases rapidly (0.14 µM/gm/sec.) to 1.0 µM/gm at 10 sec. Cooling the animal to 25, 20 or 15°C for 10 minutes increases the ST50 and decreases the rate of ATP disappearance. The ATP concentration at the corresponding ST50 increases with decreasing body temperature.
Organization of cerebral cortex. IV. Posttetanic potentiation of hippocampal pyramids
Authors: Campbell Berry , Sutin Jerome
Published: December 2017

The response of hippocampal pyramidal cells following single and repetitive stimulation of ascending fornical and commissural afferents has been studied in anesthetized rabbits and cats. Low intensity single pulse stimulation evokes a response of 10–15 msec. duration. The region of the apical dendrites is positive and the region of the cell body, basal dendrites and axon negative with respect to a distant electrode. Single stimuli did not produce a detectable efferent discharge in the alveus or fimbria. Following repetitive stimulation at 5–20/sec., a 3–5-mv potential with a duration of 3 msec. is superimposed upon the response seen following a single stimulus. This large spike shows both a tetanic and posttetanic potentiation characterized by an increased amplitude and a decreased latency. Minimal latency occurs 1–2 seconds following the termination of repetitive stimulation while maximum amplitude is attained during the repetitive stimulation. During potentiation the spike may decrease its latency up to 8 msec. When the high amplitude spike is present an efferent volley may be recorded from the alveus and fimbria. Isopotential contour mapping of these responses indicates that the spike which displays potentiation is a reflection of depolarization of the cell body and stem of the apical dendrites of hippocampal pyramidal cells.
Deep hypothermia in the cat
Authors: Battista Arthur F.
Published: December 2017

Sixteen adult cats were cooled, using the method of hypercapnia and hypoxia. Seven cats died during the cooling or warming period due to irreversible ventricular fibrillation or cardiac arrest. Nine cats survived and the lowest body temperature obtained was 12.5°C. The rate of body cooling and the oxygen and carbon dioxide concentrations were critical parameters difficult to control in a large animal such as the cat.
In vitro synthesis of coagulation factors by rat liver slices
Authors: Pool Judith G. , Robinson Jean
Published: December 2017

Rat liver slices prepared from a perfused liver were incubated in a bicarbonate-buffered salt medium; both tissue and medium were assayed for coagulation factors after various incubation periods. Although only traces of these substances were found in the freshly-excised tissue, large quantities of factor VII accumulated during the incubation. About 80% of this was in the tissue and 20% in the medium. Much smaller quantities of prothrombin were produced in the tissue but none could be detected in the incubation medium. Inhibition of both syntheses was caused by addition of NaCN, DNP, Dicumarol, warfarin, tromexan or CHCl3 to the flask, by incubation in the cold, or by substitution of a nitrogen atmosphere for oxygen. These syntheses apparently require intact cells since they did not occur in homogenized tissue nor in a system containing liver mitochondria and a protein-containing substrate. There was suggestive evidence that PTC production occurred but none that factor V or AHG was produced. It was concluded that further study of liver and other isolated tissues might provide a solution to the problem of the site of AHG synthesis.
Effect of DCA on development of renoprival hypertension
Authors: Langford Herbert G. , Snavely J. R.
Published: December 2017

The administration of DCA (desoxycorticosterone acetate) to nephrectomized dogs drinking 1% saline speeds the development of hypertension. Studies on nephrectomized rats given 0.9% saline intraperitoneally show that this is not due to increased sodium intake or overhydration.
Relationship between lymphatic and venous pressure in leg of dog
Authors: Irisawa Aya , Rushmer Robert F.
Published: December 2017

In resting, anesthetized dogs the lymphatic pressure has a value close to, but a little below, peripheral venous pressure. Contrary to previous observations the lymphatic pressure in the resting hind leg is measurable and even small fluctuations in pressure can be detected with the techniques employed. Changes in peripheral lymphatic and venous pressures are neither simultaneous nor equal. Even large changes of pressure in one system were not reflected in the other. A definite rise in lymphatic pressure was observed during spontaneous muscle movements. Fluctuation in lymphatic pressure was recorded during normal and forced abdominal respiration.
Relation of glucose tolerance factor to impaired intravenous glucose tolerance of rats on stock diets
Authors: Mertz Walter , Schwarz Klaus
Published: December 2017

Intravenous glucose tolerance tests were made on male Sprague-Dawley rats, raised on different diets. Two natural diets (McCollum's wheat-casein ration and table scraps) produced glucose removal rates of around 4%/min. or more. In rats raised on three commercial pelleted stock rations (Purina, Hunt Club, Rockland) as well as on a semipurified Torula yeast diet, low glucose removal rates of 2.5–2.8%/min. were consistently detected after 20 or more days of feeding. The results are related to the contents, in the investigated diets, of the glucose tolerance factor (GTF), a recently described, water soluble dietary agent of low molecular weight. Development of low glucose removal rates is prevented by dietary supplementation with brewer's yeast, or with GTF concentrates from brewer's yeast or pork kidney powder. The fully developed impairment is cured within 1–2 weeks by the addition of GTF concentrates to the diet. It is also reconstituted to normal within 18 hours after stomach tubing of GTF fractions of widely different degrees of purification. This curative procedure is being used as a 24-hour test for GTF.
Metabolism of iron in the duck
Authors: Klein J. Raymond
Published: December 2017

In the duck, intravenously injected labeled iron, in amounts that did not exceed 0.1 of the plasma iron, mixed initially with about five times the amount of iron in plasma. The highest level of labeled iron in erythrocytes corresponded to about 0.75 of the injected iron. Loss of labeled iron from erythrocytes following the maximum level indicated an average red-cell lifetime of around 40 days. The loss of labeled iron from the erythrocytes was reflected by some increase in the labeled iron of other tissues and increased loss of tagged iron by excretion. Excretion of iron was of the order of 8 x 10–4 of the total body iron per day. The appearance of the labeled iron in the cytochrome c of skeletal muscle was slow compared to the entry of the iron into the muscle and into erythrocytes.
Blocking interactions between brain-stem reflex facilitation and sympathetic reflex enhancement
Authors: Kelly H. B. , Bach L. M. N.
Published: December 2017

In cats anesthetized with Nembutal the integrity of the lumbar sympathetic chain is necessary for the maintenance of the normal basal height of the patellar reflex. The centrally activated sympathetic component of brain stem enhancement of the patellar reflex is consistently and totally abolished by either surgical or chemical interference with the sympathetic supply to the hind leg. Although the use of sympatholytic drugs does not affect (presumably) synaptic facilitation of reflex activity resulting from brain stem reticular stimulation, mechanical stimulation of either the lumbar sympathetic or splanchnic nerves will cause a temporary but marked depression of this facilitation. Simultaneous stimulation of either the lumbar sympathetic or splanchnic nerves completely and consistently blocks the facilitatory effects of brain stem reticular stimulation. Conversely, simultaneous stimulation of the brain stem reticular formation consistently and totally blocks the enchancement of the patellar reflex which results from stimulation of the peripheral lumbar sympathetic or splanchnic nerves. The former phenomenon does not result from any peripheral locus of interaction between adrenaline and the innervation of the quadriceps muscle. Cross perfusion experiments indicate that the locus of interaction may involve the brain stem reticular formation.
Effects of bulbar stimulation and decerebration on visceral afferent responses in the spinal cord
Authors: Tolle Alan , Feldman Shaul , Clemente Carmine D.
Published: December 2017

In a series of adult cats immobilized with Flaxedil, the splanchnic nerve was stimulated and visceral afferent responses were recorded in the cervical spinal cord. Simultaneous stimulation of the ventromedial reticular formation (2 volts, 100/sec., 1 msec.) caused an inhibition of the visceral afferent evoked responses central to the first relay station in the cord. Following decerebration, an extinction of evoked visceral afferent responses recorded in the spinal cord was constantly observed upon successive, single-shock, splanchnic nerve stimuli. This latter phenomenon is probably due to a removal of suprabulbar influences on brain stem reticular systems modulating sensory pathways.
Role of splanchnic and lumbar sympathetic nerves in physiologic responses to fever and hypoxia in dogs
Authors: Kubicek W. G. , Geber W. F. , Geiger J. W. , Johnson E. A.
Published: December 2017

Induced fever up to 42°C rectal temperature produced an increase in oxygen consumption rate, plasma creatinine, blood lactic acid, hematocrit, blood oxygen content, blood pH, pulse rate, a decrease in blood sugar and a fall in blood CO2 content. Hypoxia superimposed upon the fever tended to produce an increase in blood pressure, hematocrit and pulse rate. Hypoxia probably depressed cerebral cortical activity in the unanesthetized febrile dogs. The most important function of the splanchnic and lumbar sympathetic nerves was apparently the control of the circulatory system and secondly the partial regulation of blood glucose probably through liberation of epinephrine from the adrenal medulla. A reduction in heat tolerance of the animals was observed after sympathectomy. The effects of anesthesia were apparently a reduced sensitivity of the respiratory centers and chemoreceptors. When compared to the unanesthetized experience, lower values were observed for oxygen consumption rate, blood pH, blood oxygen content, hematocrit, plasma creatinine and blood lactic acid, and in higher values for pulse rate, blood pressure, blood CO2 content and blood glucose.
Simultaneous determination of blood volume with Cr51 and T-1824 during hypothermia and rewarming
Authors: Fedor E. J. , Fisher B.
Published: December 2017

Dogs lightly anesthetized with ether, maintained between 23–24°C for 2 hours and rewarmed, were subjected to simultaneous determinations of red cell volume (Cr51) and plasma volume (T-1824). Red cell volume values were unchanged during the course of the experiment. Plasma volumes were significantly decreased during hypothermia and were transiently elevated during rewarming. Twenty-four hours after rewarming, total blood volume and plasma volume values were not significantly different from control values. It would seem that circulatory failure (‘rewarming shock’) is not a usual feature of rewarming following hypothermia of 2 hours duration.
Effect of niacinamide on cardiac output, cardiac excitability and membrane action potential of single cardiac muscle fibers
Authors: Huang Ting-Fei
Published: December 2017

The actions of niacinamide on cardiac output and cardiac excitability of the dog heart and on the action potentials of individual frog ventricle cells were recorded. Cardiac output was increased. The duration of the action potentials of frog heart cells and the refractory period of the dog heart were shortened significantly. This drug increases respiratory and circulatory action chiefly through a stimulatory action on the heart.
Effects of sodium nitroprusside on blood pressure responses to epinephrine
Authors: Hilton James G.
Published: December 2017

The effects of decrease in tone produced by sodium nitroprusside on the blood pressure responses to epinephrine were studied in dogs anesthetized with sodium pentobarbital. A series of graded doses of l-epinephrine bitartrate was given before and during the infusion of sodium nitroprusside and the blood pressure responses to each dose of the administered epinephrine were recorded. Four different levels of sodium nitroprusside infusion were used; 2, 5, 8 and 10 µg/kg/min. Blood pressure records were analyzed in terms of maximum blood pressure attained, actual rise in blood pressure and duration of blood pressure rise before and during the infusion. The results showed that there is a significant reduction in the maximum attainable blood pressure, but no significant change in the actual rise in blood pressure or in the duration of blood pressure responses. The amount of change in maximum attainable blood pressure was directly related to the decrease in control blood pressure resulting from the sodium nitroprusside infusion. A three-dimensional dose response curve, including dose of sodium nitroprusside, dose of epinephrine and blood pressure, has been derived.
Cardiac output and its distribution in the chicken
Authors: Sapirstein Leo A. , Hartman Frank A.
Published: December 2017

The cardiac output of the chicken has been measured by the indicator dilution technique and its distribution determined by the indicator distribution technique. The cardiac output is 218 ml/kg/min. The coronary flow fraction is 4.9% of the cardiac output, the renal flow fraction, 15.2% of the cardiac output, and the splanchnic flow fraction, 17.4% of the cardiac output. The perfusion rates of the thyroid and adrenal glands are similar to those found in the rat.
Miniature responses under ‘voltage-clamp’
Authors: Spyropoulos C. S.
Published: December 2017

A number of the properties of the giant axon membrane of Loligo pealii were studied under ‘voltage-clamp.’ Inward surges of current of such properties as are characteristic of the action potential were demonstrated following short depolarizing pulses. With an exploring microelectrode inserted into the ‘clamped’ portion of the membrane, evidence was obtained showing that this inward surge was the result of activity restricted in a small area of membrane. The inward surges of current were demonstrated to add quantally. The experiments described are consistent with the concept of the existence in the membrane of two stable potential states. Such states are also encountered in metals in contact with oxidizing agents.
Role of parotid ducts in secretion of hypotonic saliva
Authors: Brusilow Saul W. , Cooke Robert E.
Published: December 2017

A technique is described whereby intraglandular concentration patterns of saliva are developed in the resting dog parotid gland between periods of maximum stimulation. The period of rest was varied from 5 to 70 seconds. The gland was stimulated maximally following this rest period and each drop of saliva (averaging 20 mg) was separately collected and analyzed. This fluid thus represented saliva that was within the gland during the rest period until saliva newly formed in the acinus replaced it. It was found that sodium and chloride concentrations were lowered in a relatively distal segment of the gland and were raised in a more proximal segment. The depth of fall of sodium and chloride was related to the length of time the fluid remained in the gland. No change was noted in the potassium concentration until it rose in a relatively proximal portion. The results suggest that there are at least two sites within the gland which transfer electrolyte; a distal locus which reabsorbs sodium chloride and a proximal locus which elaborates relatively isotonic fluid. The suggestion is made that the former represents the ducts and the latter represents the acinus.
Biochemical response to trauma. IV. Corticosteroid levels in plasma of rats subjected to tumbling trauma
Authors: McLaughlin Joseph , Gray Irving
Published: December 2017

The effect of tumbling trauma on the concentration of corticosterone (CS) and other corticosteroids (X-steroids) in the plasma of rats has been followed using a fluorimetric method for the analyses of the corticosteroid. Sprague-Dawley rats weighing 225–275 gm were used. The animals were tumbled for 300, 400, 500, 600 and 700 turns giving a 24-hour mortality ranging from 0 to 100%. The corticosterone levels immediately after the tumbling were increased 2–5 times while the X-steroid concentrations increased 5–10 times. When followed in time after tumbling, the corticosterone remained elevated for 1–2 hours and returned toward normal within 24 hours whereas the X-steroids rose to a peak about 1 hour and then fell to near zero between 1 and 2 hours after which a secondary rise occurs which rises about 8 hours and then returns toward normal within 24 hours.
Effects of intravenous administration of a fat emulsion on blood coagulation in dogs
Authors: Shoulders Harrison H. , Hartmann Robert C. , Meng H. C.
Published: December 2017

A fat emulsion prepared for intravenous administration has been studied with regard to its effect upon blood coagulation in dogs. The most characteristic effects found during intravenous infusion of this material at a rate of 1 ml/min. were thrombocytopenia and marked shortening of clotting time. These effects were invariably observed in animals which had not previously received the emulsion. When subsequent infusions were given within 3 hours, no significant changes were observed. When the interval was extended to 1–13 days, variable responses occurred, at times characterized by pronounced hypocoagulability. If the repeat infusion was given 2 weeks or more after the initial one, the effects were similar to those observed during the first infusion. The prothrombin and thrombin clotting times and plasma fibrinogen concentration were not greatly altered during the infusion. Abnormal bleeding time, ‘prothrombin utilization’ and clot retraction accompanied the thrombocytopenia.
Effects of phosphoethanolamine and phosphoserine on blood coagulation mechanism
Authors: Koppel J. L. , Mueller D. A. , Novak L. V. , Olwin J. H.
Published: December 2017

Phosphoethanolamine and phosphoserine were studied for their in vitro effects on various phases of the blood coagulation mechanism. When added to freshly drawn, normal human blood both substances exhibit marked anticoagulant characteristics. When added to normal human plasma in the presence of either brain extract thromboplastin or Russell viper venom they produce an inhibition of clot formation which becomes more pronounced with increasing concentration. The effects observed appear to be due to an interference with thrombin formation rather than to an inhibition of the thrombin fibrinogen reaction. Evidence has been obtained which suggests that, depending upon their concentration, phosphoethanolamine and phosphoserine may inhibit either the formation of a prothrombin-converting principle only or inhibit, in addition, the activity of this principle as well.
Effect of norepinephrine and 5-hydroxytryptamine on the pulmonary circulation of the spinal dog
Authors: Nahas Gabriel G. , MacDonald I.
Published: December 2017

One microgram of norepinephrine per kilogram of body weight injected in a 1-ml volume into the right atrium had little direct effect on the mean pulmonary artery pressure of dogs with intact nerve supply. The changes observed occurred simultaneously with systemic changes. In the spinal vagotomized dog, a similar dose produced a rise in mean pulmonary artery pressure which preceded any other pressure change. The isolated pulmonary hypertension produced in the intact animal by an identical dose of 5 HT is not modified after vagotomy or spinal section.
Tissue pressure and critical closing pressure in the dog kidney
Authors: Hinshaw Lerner B. , Day Stacey B. , Carlson Curtis H.
Published: December 2017

The study was undertaken to investigate a possible relationship between renal tissue pressure and the arteriovenous pressure difference at zero flow in the dog kidney. Experiments were performed on the isolated blood perfused kidney and on the kidney in situ in the eviscerated dog. Continuous strain gauge recordings of the arterial pressure, tissue pressure and rates of weight loss (venous outflow) were obtained after cessation of the renal arterial inflow. Results indicate a positive arterial pressure intercept at zero flow, but provide evidence for the absence of a general critical closing pressure in the dog kidney. After arrest of the renal arterial inflow the arteriovenous pressure difference fell to a mean value of 1.7 mm Hg as tissue pressure declined to a mean of 2.9 mm Hg and the venous outflow approached zero. It is suggested that the existing renal tissue pressure acts as a collapsing force on renal blood vessels producing a positive arteriovenous pressure difference at zero flow. A general ‘critical closing pressure’ need not be postulated to account for these findings.
Renal concentrating operation in hypothermic dogs
Authors: Hong Suk Ki , Boylan John W.
Published: December 2017

The renal concentrating operation during hydropenia and during constant infusion of 2 m urea in isotonic saline was studied in 10 anesthetized dogs. PAH, exogenous creatinine and osmolal clearances were determined, as well as rates of Na and Cl excretion. Following two to four control periods body temperature was lowered to approximately 25°C by the use of an ice-water bath. The above measurements were then repeated during this steady state of hypothermia. PAH and creatinine clearances are reduced to approximately one-third of control values, while urine flow is not significantly changed. Thus, proportionately less filtered water is reabsorbed. Osmolal clearance is reduced, but this reduction is less than that of GFR so that a decrease in the tubular reabsorption of filtered osmotic particles occurs in hypothermia. This reduction in tubular reabsorption of solute is revealed further in a two to threefold increase in the percentage excretion of filtered NaCl and total osmotic substance. A greater decrease in the process which removes free water (TcHH2O) from the supposedly isotonic tubular fluid results in a reduction to one-third to one-fourth of the control values for TcHH2O. There would appear to be a dissociation of water and solute reabsorptions in hypothermia which indicates a decrease in the renal concentrating process.
Development of an isolated perfused mammalian kidney
Authors: Rosenfeld Sheldon , Sellers Alvin L. , Katz Joseph
Published: December 2017

This study describes the development and functional evaluation of an artificial heart-lung perfusion system in which whole blood is used to perfuse the isolated rabbit kidney. Data are presented which indicate that this preparation is capable of attaining normal or near normal function at some time during the course of the experiment in at least 40% of the last 26 experiments. Functional evaluation of the perfused kidney is made by measuring the observed renal blood flow, rate of urine flow, and extraction ratios and clearances of creatinine and PAH. In a limited number of experiments, it has been shown that in the isolated perfused kidney, there is considerable active reabsorption of glucose and sodium. Furthermore, the same response to drugs and hormones, known to affect kidney function in the intact animal (papaverine, renin and Pitressin), has been demonstrated.
Abdominal compression reaction: causes and characteristics
Authors: Gilfoil T. M. , Youmans W. B. , Turner J. K.
Published: December 2017

In most dogs which receive sodium pentobarbital in doses of 30–40 mg/kg a strong contraction of the abdominal muscles begins just after the termination of expiration and persists until just before the next inspiration. When the reaction does not appear following injection of an initial does of 30 mg/kg of sodium pentobarbital, which is the result in about half of the experiments, the injection of an additional 6–10 mg/kg frequently will cause its appearance. The reaction regularly can be elicited or intensified by injection of nitroglycerin in dogs anesthetized with sodium pentobarbital. The abdominal compression reaction (ACR) shows variations in amplitude independent of changes in rate or amplitude of breathing. It is a coordinated, interrespiratory activity of the abdominal muscles which is controlled separately from breathing. It is postulated that the ACR is of importance in maintaining the return of blood to the heart.
Effects of epinephrine on lactic and keto-acid production, phosphate balance and pH changes in the isolated perfused frog liver
Authors: Craig Albert B.
Published: December 2017

The study of the isolated perfused frog liver has been extended to show that epinephrine will cause an increase in lactic acid and keto-acid production. This reaction is brief and corresponds to the period of potassium loss. A decrease in the pH of the effluent was noted. The duration of this change mimics the course of increased glucose production. No change in the phosphate balance could be detected. These results are discussed as they relate to the present views of epinephrine action.
Effect of glucose and inosine triphosphate on seasonal variation of gastric acid production in Rana pipiens
Authors: Mizell Sherwin
Published: December 2017

The production of acid in vitro by the gastric mucosa of 375 Rana pipiens was studied over a period of 13 months. The frogs were kept at 21°C and histamine was used to induce secretion. Four conditions were studied: a) control, no substrate added to the nutrient solution; b) 10 mm glucose added; c) 0.6 µm inosine triphosphate (ITP) added and d) 10 mm glucose and 0.6 µm ITP added. For each mucosa the change in hydrogen ion concentration (ΔpH), titrable acidity and total chloride produced were measured. The results indicate that the seasonal variation in gastric acid production is due, in part, to a variation in the availability of substrate normally present.
Effect of pH on norepinephrine-induced contractions of isolated arterial smooth muscle
Authors: Tobian Louis , Martin Stephen , Eilers William
Published: December 2017

Isolated muscle strips, spirally cut from the rat aorta, were suspended in various Krebs solutions which simulated conditions of respiratory and metabolic acidosis. The contraction of these strips following exposure to norepinephrine was found to be maximal in states of relative alkalosis and minimal in states of acidosis. In ‘respiratory acidosis,’ the inhibition of the norepinephrine-induced contraction averaged 43%. In a comparable ‘metabolic acidosis,’ the inhibition was markedly less but still averaged 26%. In a more severe ‘metabolic acidosis,’ the inhibition was 32% when compared to a solution with a ‘normal’ pH. In solutions with a ‘normal’ pH, the combination of a high CO2 tension and a high bicarbonate concentration will also inhibit a norepinephrine-induced contraction when compared to a solution of the same pH with the combination of a low CO2 tension and a low bicarbonate concentration. The observations suggest that correction of the acidosis which often accompanies shock should make the shock more amenable to treatment.
Statistical properties of near threshold responses to brief sounds in the MES auditory cortex of the anesthetized dog
Authors: Tunturi Archie R.
Published: December 2017

Evoked responses to near threshold p pulses recorded with a 50-channel cathode ray oscilloscope from the MES auditory cortex were analyzed statistically. Observations were taken at 3-msec. epochs for approximately 180 msec. Density functions of the evoked potential at these epochs were essentially normal. The average potential from a single electrode consisted of an initial positive followed by a negative component. The correlation coefficient between the positive and negative components was zero suggesting independence. Standard deviation increased during the positive component of a response decreasing to the zero crossing or was followed by a secondary component. Spatially, in the anterior-posterior direction, the average potentials decremented to approximately zero in 2–4 mm. The decrement was less prominent dorso-ventrally. Spatially, the standard deviation showed the same pattern as the mean.
Response of a parasympathetic neuroeffector system to motor nerve stimulation
Authors: Carpenter F. G. , Tankersley J. C.
Published: December 2017

The pressure response of the feline urinary bladder to motor nerve stimulation was measured by a strain gauge connected to a urethral catheter. In lightly anesthetized cats the magnitude of the responses produced was a hyperbolic function of the stimulation frequency within the range of .5–20 impulses/sec. Blockade of the ChE system by the administration of 1 mg/kg of prostigmine with or without arrest of the bladder circulation failed to alter the characteristics of this response. Our findings suggest that these graded responses of bladder smooth muscle at different stimulation frequencies is dependent upon a mechanical summation of individual ‘twitch’ responses. The response magnitude is in a way proportional to the concentration of ACh. Contractions resulting from repetitive stimulation at rates of 10–15/sec., achieved optimal summation. At stimulation frequencies below 5/sec. the efficiency of mechanical summation in the bladder smooth muscle diminished. When the interval between stimuli was increased to 200 msec. (5/sec.) the summated response of the smooth muscle established a lower plateau. It is suggested that the smaller responses found at the lower frequencies may be related in part to the tendency of smooth muscle units to restore themselves to the resting state independently of high ACh concentrations.
Diurnal body temperature variations and hibernation in the birchmouse, Sicista betulina
Authors: Johansen Kjell , Krog John
Published: December 2017

Body temperatures, oxygen consumption and electrocardiograms were recorded in the birchmouse. The diurnal body temperature cycle ranged from 5° to 18°C during a regular 24-hour sequence. The highest body temperatures (37–38°C) are present around midnight, coinciding with the time of maximal activity. Body temperatures and oxygen consumption were studied at various ambient temperatures. With decreasing temperature the oxygen consumption commonly followed two successive patterns: first, a period of compensatory increase after which body temperature and oxygen consumption decreased; the compensation lasted from 5 minutes to 4 hours. At low ambient temperatures the animals went into a state of dormancy similar to seasonal hibernation in other mammals. The reduction in heart and respiratory rate as well as in oxygen consumption and body temperature confirmed those values reported earlier. Arousal from hibernation in the birchmouse is unique in the great speed of reaction with which the awakening takes place. Body temperature may increase as much as 1°C/min. and, within a period of 30 minutes, the oxygen consumption may increase 25 times.
Experimental induction of hypercholesteremia and its subsequent effects on plasma phospholipid and triglyceride
Authors: Byers Sanford O. , Friedman Meyer
Published: December 2017

A sustained rise in plasma cholesterol concentration, brought about by intravenous infusion of cholesterol suspension (11 rats) or of cholesterol-rich intestinal lymph (5 rats), was not followed by a significant rise in phospholipid above control values. Neither was any tendency to prolongation of triglyceridemia observed as a consequence of cholesterol rise. Nine rabbits fed a diet containing 2% cholesterol and 2% cottonseed oil showed progressive increase of plasma cholesterol concentration each month for 3 months. Plasma phospholipid, however, was the same at the end of each of the 3 months. These results suggest that excess cholesterol in plasma does not act as a hyperphospholipidemic agent. Even when cholesterol and triglyceride are fed chronically, plasma phospholipid level does not seem to be closely related to the observed rise of cholesterol.
Transmembrane potentials and fluxes in isolated rabbit atria
Authors: Klein R. L. , Holland W. C.
Published: December 2017

Data are presented from a study of transmembrane potentials and unidirectional fluxes of K42 under identical conditions in isolated rabbit atria. The effects of acetylcholine and varying extracellular concentrations of Na, K and Ca were investigated. Particular emphasis has been placed on the role of Ca and on the terminal phase of repolarization of the action potential, namely the negative after potential. Data are given which support the contention that the duration of the negative after potential depends on an active transport of K or Na, or both.
Small vessel responses of the rabbit ear
Authors: Davis D. L. , Hamilton W. F.
Published: December 2017

Blood pressures were recorded continuously from small arteries and veins of the rabbit ear by inserting 0.1 mm o.d. glass cannulae through the dorsal skin into the lumen of 0.3–0.5 mm diameter vessels. The cannulae did not occlude the lumen of the vessels. Stimulation of the third cervical nerve produced an elevation in small artery pressure, and an abrupt fall in small vein pressure with little evidence of increased small vein resistance. Stimulation of the cervical sympathetic trunk produced a marked decrease in small artery pressure. Pulsations ceased and the small arteries became bloodless. The small vein pressure exhibited an evanescent rise followed by a gradual fall. Mechanical occlusion of the macroscopically visible small veins enhanced the initial elevation in small vein pressure in response to stimulation of the sympathetic trunk. With reduced body temperature and the same degree of mechanical occlusion a maintained elevation of small vein pressure occurred throughout the entire stimulation period. This can be interpreted as the result of constriction of the small vein walls upon a column of blood held static in the occluded vein.
Hormonal factors influencing postirradiation creatinuria and polyuria in the rat
Authors: Krise G. M. , Williams C. M.
Published: December 2017

Normal albino rats exposed to 1500 r of whole-body Co60 gamma radiation were found to have a significant increase in urinary creatine excretion for the first 3 postirradiation days. Adrenalectomized rats, irradiated at 8 days postoperatively, did not show a creatinuria significantly greater than nonirradiated controls. Thyroparathyroidectomized rats, irradiated at 8 days postoperatively, did not have a significant increase in urinary creatine excretion over that of nonirradiated fasted controls. There were no significant increases in polyuria or polydipsia on the 1st postirradiation day in either the adrenalectomized or thyroparathyroidectomized rats. The intramuscular injection of 500 mu of the antidiuretic hormone vasopressin (Pitressin tannate) in oil inhibited postirradiation polydipsia and polyuria in normal rats but significantly increased the urinary excretion of creatine over that of irradiated noninjected controls.
Transport of radioiodide between thyroid gland and blood in mice and rats
Authors: Wollman Seymour H. , Reed Franklin E.
Published: December 2017

Page 117: Seymour H. Wollman and Franklin E. Reed, "Transport of radioiodide between thyroid gland and blood in mice and rats." Column 1, the introductory line to equation 2 was omitted. Should read: If IB is constant, integration of equation 1 yields:
Effect of population density on adrenal glands and reproductive organs of CFW mice
Authors: Southwick Charles H. , Bland Vivian P.
Published: December 2017

Young mice of the CFW albino strain were subjected to fixed population densities of 1, 4, 8 and 16 animals/cage after a 3-week period of isolation. After 1 week of such groupings, the animals were sacrificed, the adrenal glands, testes and seminal vesicles were weighed and histological preparations were made of the adrenal glands. The increased adrenal weights and decreased reproductive organ weights reported by Christian ( Am. J. Physiol. 181: 477, 1955; 182: 292, 1955) did not occur in the group means of male populations. Increased relative adrenal weights (mg adrenal weight/gm body weight) did occur in wounded animals of these populations, however. Increased relative adrenal weights of males also occurred in populations containing 50% females. Increased adrenal weight was usually, but not consistently, associated with increased cortical width. Testes weights were unaffected by population density. Seminal vesicle weights declined with increasing population density. Crowding increased fertility in groups of 4 and 8, whereas, it impaired fertility in groups of 16.
Utilization of blood urea in ruminants
Authors: Houpt T. Richard
Published: December 2017

Utilization of injected urea and urea transfer from blood to rumen were investigated. First, urea ( ca. 5 mmole urea-N/kg body weight) was injected intravenously into mature sheep receiving a low-protein, carbohydrate-supplemented ration. Part of the injected urea was recovered in urine as excess over basal excretion. 52% (S.D. = 10) of injected urea was not recovered in urine nor remained in body fluids and presumably was utilized in rumen protein synthesis. Without dietary carbohydrate supplements utilization decreased to 22% (S.D. = 5). Second, ingesta of the rumeno-reticular cavity were replaced with saline; and accumulation of ammonia, representing a hydrolytic product of urea, was measured. Concurrent absorption of ammonia was estimated using arteriovenous urea and ammonia concentration data. Total urea-N transfer, the sum of ammonia-N accumulation and absorption plus salivary urea-N, for sheep was 5.2 mmole urea-N/hr. (S.D. = 0.8), of which 0.3 mmole/hr. was in saliva. Similar results were obtained in the goat.
Influence of androgens on the transaminases and glutamic dehydrogenase of tissues
Authors: Kochakian Charles D. , Endahl Barbara R. , Endahl Gerald L.
Published: December 2017

Aspartic-glutamic and alanine-glutamic transaminase activities of the kidney and heart of the rat and mouse change in direct proportion with the changes in weight produced by castration and testosterone. The transaminase activities of the rat but not the mouse liver are decreased by castration and restored to normal by testosterone propionate administration. The glutamic dehydrogenase activity of the liver and kidney of the rat and the mouse is not altered by castration or androgen administration. An increase of the kidney weight above normal size by androgen, however, is accompanied by a proportionate increase in the enzyme.
Effects of lung collapse on pulmonary blood volume, flow and resistance
Authors: Barrios Alceo , Fell Colin , Hamilton W. F.
Published: December 2017

Pulmonary blood flow, pressures, volume and vascular resistance were measured when the lungs occupied an expiratory position in the closed chest and when they were collapsed by introducing air into the thorax. Circulation and innervation were intact. Variations due to respiratory movements or asphyxia were ruled out. Mongrel dogs were used, anesthetized with morphine and sodium pentobarbital. Pressures were measured from pulmonary artery, left atrium, aortic arch and intrapleural space. Pulmonary flow was evaluated utilizing the dye dilution method and the pulse contour method. Vascular volume was estimated by the product of mean circulation time and flow. When the lungs were collapsed there was an immediate elevation of intraluminal left atrial pressure but not a comparable rise in pulmonary arterial pressure. However, the direct records of arteriovenous pressure drop suggest that there was a delayed rise in pulmonary artery pressure. Flow, aortic pressure, heart rate and pulmonary vascular resistance showed no consistent changes. In 8 of 11 cases the pulmonary blood volume decreased when the lungs were collapsed.
Chronic effects of carotid sinus denervation, cervical vagotomy and aortic depressor nerve section on aldosterone and sodium excretion
Authors: Davis James O. , Yankopoulos Nicholas A. , Holman John
Published: December 2017

Carotid sinus denervation in dogs and aortic depressor nerve section in rabbits were without effect on urinary aldosterone and sodium (Na) excretion. Also, adrenal vein aldosterone output following both acute and chronic carotid sinus denervation was unaltered. Constriction of the thoracic inferior vena cava in dogs with carotid sinus denervation resulted in hyperaldosteronuria, marked Na retention and ascites, a response in no way different from that occurring in intact dogs. Subsequent unilateral cervical vagotomy had no detectable influence on the hyperaldosteronism and Na retention. Section of the remaining vagus resulted in a slight increase in Na excretion, but Na balance remained positive and ascites continued to accumulate. Since the increase in Na excretion was meager and the continued high rate of aldosterone output occurred in two of three dogs, it seems unlikely that the vagus constitutes an appreciable part of an afferent nervous limb. The data offer no support for the concept that receptors concerned with the control of aldosterone secretion or Na excretion are located in the aortic arch or carotid sinus.
Active transport of epinephrine into blood platelets
Authors: Sano I. , Kakimoto Y. , Taniguchi K. , Takesada M.
Published: December 2017

An active transport of serotonin was demonstrated in a previous report from this laboratory on rabbit blood platelets. Epinephrine is known to be taken up by the blood platelets as serotonin when the cells are suspended in plasma. In this paper evidence of an active transport of epinephrine is presented. The absorption of this amine is the movement into the cell against a concentration gradient. Epinephrine added to the suspending medium accumulated in the cells, after 1 hour's incubation at 37°C, when glucose or its metabolites were present. The concentration of the amine rose to 1 or 2 µg from about 0.005 µg/mg dry weight of platelets. Glucose, pyruvate, acetate, α-ketoglutarate and fumarate were the effective stimulators. The effect of glucose was diminished by the presence of sodium fluoride, iodoacetate, 2,4-dinitrophenol and reserpine. Competitive inhibitions of the active transport by aromatic compounds containing ethylamine groups might suggest the participation of the amine group of epinephrine in its transport. In contrast, serotonin transport was inhibited by a 5-hydroxyindol compound.
Transfer of radioactive iron via the placenta and accessory fetal membranes in the rabbit
Authors: Davies J. , Brown E. B. , Stewart D. , Terry C. W. , Sisson J.
Published: December 2017

The distribution of radioactivity in the fetus and placental structures was studied at different stages of gestation in the rabbit following the intravenous injection of radioactive iron as Fe59 sulphate. The following general results were obtained: a) A steady increase in the uptake of radioiron by the fetus and fetal placenta took place with advancing gestation. The rate of uptake showed a sharp increase at about the 20th day. b) The rate of iron transport across the placenta increased during gestation, especially in the last third of pregnancy. c) Radioiron was concentrated in the yolk sac in the early stages and in the fetal liver in the later stages of gestation. No change in the pattern of accumulation of radioiron by the fetus took place when the vessels of the yolk sac were ligated before injection. These results suggest that the yolk sac has no role in iron transport and that early in gestation it may carry on some of the functions of the fetal liver with respect to iron. d) Alternative sites of transport for iron were investigated by the injection of radioiron into the uterine cavity. The results indicate that if iron gains access to the uterine cavity, e.g. via the uterine mucosa or via the chorion and periplacental decidua, it is rapidly absorbed by the yolk sac and enters the fetus. However, such a pathway for iron transfer to the fetus does not seem to be important physiologically.
Relation of the metabolism of sulfobromophthalein sodium to its blood clearance in the rat
Authors: Krebs John S.
Published: December 2017

Chromatographic analysis of BSP (sodium phenoltetrabromphthalein disulfonate) excreted into the bile of the rat showed that the BSP had undergone transformation into similarly colored but chemically different compounds. Injection of purified samples of these derived compounds into the rat showed that the compounds were less effectively removed from plasma than BSP but were excreted into bile at almost the same rate as when pure BSP was injected. Chromatographic analysis of bile following injection of the isolated bile-type derivatives of BSP showed that the derivatives were formed, one from the other, in a chain sequence, starting with BSP. Chromatographic analysis of the blood following injection of BSP showed that bile-type derivatives of BSP appeared in the blood and became progressively more predominant with increasing time after injection of the BSP.
Electrolyte and lipid composition of skeletal and cardiac muscle in mice with hereditary muscular dystrophy
Authors: Young Ho Lee , Young Wei , Edelman Isidore S.
Published: December 2017

Skeletal and cardiac muscle from strain 129 mice with hereditary muscular dystrophy and from their normal littermates were analyzed for sodium, potassium, total lipids and the separate lipid components. Dystrophic skeletal muscle contained 12–23% less potassium and 68–107% more sodium than the normal anatomical counterparts when referred to fat-free dry weight. Cardiac muscle from dystrophic mice did not differ from the normal in potassium content and had only 20% more total lipid. Fat content was substantially greater in dystrophic skeletal muscle than in normal muscle by the following percentages: 92% for total lipids, 168% for triglycerides, 140% for total cholesterol and 87% for nonesterified fatty acids assayed by infrared analysis. The phospholipid content of dystrophic and normal skeletal muscle, however, was approximately the same. The lack of information concerning interstitial connective tissue content of these tissues bars any precise interpretation of the electrolyte or lipid changes in this genetic myopathy.
Body fluid shifts in the dog during hypothermia
Authors: Farrand Richard L. , Horvath Steven M.
Published: December 2017

The rectal temperature of dogs was reduced to 27°C and stabilized at this level for a period of at least 3 hours. The heart rate, blood pressure, respiration rate, blood volumes, extracellular volume (thiocyanate space), and total body water (antipyrine space) were recorded during the reduction in temperature and the period of stable body temperature. No change was observed in the mean arterial pressure during any period of hypothermia; the heart rate decreased exponentially during the reduction in body temperature but remained constant during the stable period. Blood volume increased during the initial stages of hypothermia (33°C to 36°C) and remained at this level. Hematocrit and erythrocyte volume followed the same pattern as total blood volume, with no alteration in the plasma volume. There were no shifts in the extracellular or intracellular volumes at any time during the hypothermic state.