bluuebunny/crossref_metadata_2025 huggingface dataset:
Intracellular hydrogen ion changes and potassium movement
Authors: Brown E. B. , Goott Bernard
Published: December 2017

Intracellular hydrogen ion concentration was determined on skeletal muscle by the DMO technique in dogs subjected to various acid-base alterations. The data verified the fact that a given alteration in Pco2 produces a larger hydrogen ion change in intracellular fluid than in extracellular fluid. In spite of this, however, the ratio (See PDF) decreased. On the basis of this change in ratio, the Donnan equilibrium would predict that potassium would move from intracellular to extracellular compartment and not in the reverse direction as had been assumed previously. Using the change in plasma potassium as the criterion of direction of movement of potassium between intracellular and extracellular fluids, the movement of potassium produced by any of the acid-base alterations which were studied was usually that which would be predicted by the Donnan equilibrium.
Feeding frequency and protein metabolism
Authors: Cohn C. , Joseph D. , Bell L. , Oler A.
Published: December 2017

Normal young adult male rats were allowed to eat a diet of a specified protein content ad libitum, or were pair-force-fed the same diet twice a day. At the end of 14 days of controlled feeding, the animals were killed and analyzed for total body lipids. These analyses showed that the fat content of the force-fed animals, relative to those that ate ad libitum, became progressively greater as the dietary protein was increased in quantity from 0 to 67% of the diet. Furthermore, it was observed that force-fed animals excreted about 37% more urea nitrogen over a 7-day period than pair-fed animals eating ad libitum. Abruptly reversing the feeding habits of the rats immediately reversed the relative amounts of urinary nitrogen they excreted. The results of both types of experiments suggest that the intermediary metabolism of protein is related to feeding frequency (or load of absorbed nutrients to be metabolized per unit time). With fewer feedings but with total 24-hr intake constant, less dietary protein appears to participate in protein anabolic reactions since larger amounts of nitrogen are lost in the urine.
Influence of analogues of phenylbutazone on renal transport of 4-aminohippurate
Authors: Despopoulos Agamemnon , Pendergrass Lloyd H. , Stoeckinger John M.
Published: December 2017

Analogues of phenylbutazone were tested for inhibitory potency in the renal transport mechanism for 4-aminohippurate. In a series of ten compounds examined by an in vitro technique, no correlation could be demonstrated between inhibitory potency and acidic strength of the inhibitor either in rabbit or in dog tissues. In a further series of 16 paired analogues, the hydroxylated member of each pair was 3–4 times less potent than its unhydroxylated counterpart. Correlations between molecular structure and pharmacological activity are suggested. In contrast to these observations, each of three selected phenylbutazone analogues (phenylbutazone, metabolite II, and sulfinpyrazone) depressed the maximum tubular excretory rate for 4-aminohippurate in intact dogs, but apparent inhibitory potencies by the clearance technique were unrelated to inhibitory potencies in dog kidney slices. Differences in relative potencies thus obtained are attributed to differences in metabolic alteration of each compound at extrarenal sites in intact dogs.
Hemodynamic effects of altering the timing of atrial systole
Authors: Skinner N. Sheldon , Mitchell Jere H. , Wallace Andrew G. , Sarnoff Stanley J.
Published: December 2017

The use of heart block dog preparations allowed an investigation at constant ventricular rates of the hemodynamic effects which resulted when the timing of atrial systole was altered relative to ventricular systole. Ganglionic blockade and vagotomy precluded sympathetic reflex compensation in these animals. Lengthening or shortening the interval between left atrial and left ventricular systole (As-Vs interval) produced a decrease in left ventricular end-diastolic pressure (LVEDP), mean aortic pressure, and aortic flow. Mean left atrial pressure (MLAP) increased as did the relation of MLAP to LVEDP. The absence of atrial systole produced similar changes. Lengthening or shortening the As-Vs interval while holding aortic pressure and stroke volume constant resulted in an increase in MLAP and the relation of MLAP to LVEDP. The changes observed in the left atrial pressure tracings suggested and a platinum electrode technique demonstrated that mitral regurgitation can occur with improper timing of atrial systole. The data indicate that properly timed, effective atrial activity can enhance ventricular filling and can preclose the atrioventricular valve.
CO2 dissociation curve of dog brain
Authors: Kazemi Homayoun , Mithoefer John C.
Published: December 2017

The CO2 dissociation curve of canine brain has been determined in vitro immediately after death, as well as the CO2 solubility coefficient, water content, and density of brain. The slope of the CO2 dissociation curve of brain is .36 ml CO2/100 g brain per mm Hg at 37 C over the range of pCO2 from 5 to 60 mm, .23 from 60 to 150 mm, and .15 at pCO2 values above 150 mm Hg. Problems of measurement of CO2 dissociation curve of brain are discussed and evidence presented which justifies the acceptance of the CO2 dissociation curve presented here as nearly representing that which exists in the dog in vivo. It is shown that postmortem acid formation by the brain is dependent upon hypoxia and can be prevented by high O2 tensions. The previous observation that it can also be prevented by rapid cooling is confirmed.
Uptake of plasma free fatty acids by the isolated rat liver: effect of glucagon
Authors: Aydin Abdullah , Sokal Joseph E.
Published: December 2017

The uptake of oleate by the isolated perfused rat liver was studied over the range of plasma free fatty acid (FFA) concentration from 100 to 1,800 µEq/liter. Hepatic removal of FFA could be described as a linear function of the FFA concentration in blood entering the liver. When appropriate correction was made for the difference in metabolic rates of the two species, it was found that the isolated rat liver removed FFA from its perfusing blood at rates quite comparable to those reported for the dog liver in vivo. An effect of glucagon on FFA uptake rates could not be demonstrated, either with fasted or with glycogen-containing livers. This experimental system, which offers the advantages of relatively easy control of many variables and of exclusion of the effects of other organs, appears well suited for studies of fatty acid metabolism in the liver.
Mechanisms of intrarenal hemodynamic changes following acute arterial occlusion
Authors: Hinshaw Lerner B. , Page Barbara B. , Brake Charles M. , Emerson Thomas E.
Published: December 2017

The hemodynamic response of the kidney to acute arterial occlusion is poorly understood. The purpose of the present study was to determine intrarenal hemodynamic changes in intact and isolated kidneys following arterial occlusion. The relative roles of metabolic, myogenic, and tissue pressure influences on the postocclusion response were evaluated. The response of the kidney to occlusion was found to be complex, depending on the interaction of a variety of physical and humoral forces. Increases in renal resistance appeared to be due, in part, to adrenergic agents and were enhanced by extending time of occlusion and lowering the arterial pressure. The combined effects of prevenous dilatation and diminished tissue pressure resulted in a decreased resistance following shorter periods of occlusion. Prevenous dilatation was accounted for by depressed vascular sensitivity to pressor agents and the presence of vasodilator substances. Changes in venous segment resistance were found to be of primary importance in both the autoregulatory phenomenon and the postocclusion hyperemic response to short (15-sec) occlusion periods.
Effect of exercise and lactic acid infusion on individual free fatty acids of plasma
Authors: Gold Martin , Miller Harvey I. , Issekutz B. , Spitzer John J.
Published: December 2017

The effect of exercise and lactic acid infusion was studied in nonanesthetized dogs. Both procedures decreased the plasma free fatty acid level (FFA) as well as the concentration of the major individual fatty acids (palmitic, palmitoleic, stearic, oleic, and linoleic acids) of FFA. The percentage contribution of oleic and frequently of linoleic acid to the total FFA was also diminished after exercise or lactic acid infusion. Similar alterations in FFA were also observed due to Nembutal or morphine-chloralose anesthesia. The changes observed during exercise, or lactic acid infusion were similar to those produced by the administration of insulin or glucagon and opposite to those produced by epinephrine or norepinephrine.
Dim light vision of Squilla mantis L
Authors: Schiff H.
Published: December 2017

The anatomy of the eye of Squilla mantis and the geometrical optics derived from it are briefly described. The shape and size of the electroretinogram (ERG) are dependent on a) position where it is picked up, b) the light intensity, and c) the change of intensity. Single-fiber analysis confirms the results obtained by the anatomy and the ERG of the eye. Frequency of response of a single secondary fiber to intensity changes of light is proportional to the derivate dI/dt ( I = intensity; t = time). The Squilla sees a moving object as the sum of the intensity changes caused by that object, varied in time and space. The eyes have a maximum of sensitivity for light of 535–555 mµ wavelength, and a second maximum in the near ultraviolet light, the latter partly seen as green fluorescence due to an eye pigment. Anatomy, physiology, and the environmental conditions have been combined to explain the vision of this animal, adapted to his life in the blue-violet twilight of the deeper Mediterranean sea.
Inhibition induced by forebrain stimulation in the monkey
Authors: Rubinstein Eduardo H. , Delgado José M. R.
Published: December 2017

Eleven monkeys were equipped with fixed or with movable intracerebral electrodes and some of these animals were stimulated by radio control. Several types of inhibitory effects were observed: 1) Specific inhibition of the approaching, taking up, and consummatory phases of alimentary reaction was induced by stimulation of the rostral caudate nucleus and medial septum. Aggressiveness was also inhibited, while other individual and social responses were not modified. The participation of a caudate-septal system in the regulation of food intake is suggested by these experiments. 2) General inhibition of behavior was evoked by caudate stimulation at the commissural level. 3) Partial inhibition of alimentary reactions was elicited by stimulation of amygdala and thalamus. 4) Autonomic inhibition affecting heart rate and respiration followed excitation of the central caudate with single shocks or with frequencies up to 100 cycles/sec. 5) Inhibition of conditioned avoidance was observed during caudate stimulation. However, the same caudate excitation could be used as a cue if the response was reinforced. In self-stimulation experiments the rostral caudate proved to be neutral.
Defect in glucose metabolism in aortic tissue from alloxan diabetic rabbits
Authors: Yalcin Saliha , Winegrad Albert I.
Published: December 2017

The glucose, raffinose, and inulin spaces in tubular sections of rabbit thoracic aorta were compared. The glucose space exceeded the raffinose and inulin spaces in tissue from normal rabbits. Insulin in vitro did not alter the relative sizes of the glucose and raffinose spaces in tissue from normal animals. In aortic tissue from alloxan diabetic rabbits, the glucose space exceeded the raffinose space, and the ratio of these spaces was unaltered by insulin in vitro. Hexokinase activity was significantly reduced in tissue from diabetic rabbits. Aortic hexokinase activity was inhibited by glucose 6-phosphate, and no activity resembling hepatic glucokinase was detected. Phosphohexose isomerase and phosphohexokinase activities were not significantly different in normal and diabetic tissues. Transport into cells does not appear to be a rate-limiting step in glucose utilization by aortic tissue from normal or diabetic rabbits incubated in vitro. The impaired glucose utilization previously observed in tissue from diabetic rabbits appears to be related to decreased glucose phosphorylation which may be localized at the hexokinase reaction.
Effect of dietary sucrose and starch on oral glucose tolerance and insulin-like activity
Authors: Cohen A. M. , Teitelbaum A.
Published: December 2017

Substituting sucrose for starch, while keeping the fat, protein, salts, and vitamins of the diet constant, resulted in impaired oral glucose tolerance in rats. The time needed to develop impaired tolerance varied with the percentage of sucrose in the diet. In animals fed a diet containing 67% sucrose this took 21–40 days, whereas in rats fed diets with 40 or 33% sucrose, it took 40 and 100 days, respectively. This impairment was reversible if the animals were put back on starch diets, but only a few days were then required to redevelop the impaired tolerance when they were refed the sucrose diet. No difference was found between animals fed carbohydrates as starch and those fed the animal stock diet. Sucrose-fed animals showing an impaired tolerance had more fat in the liver and reduced insulin-like activity in the serum.
Mechanism of action of pancreatic stimuli studied by means of atropinelike drugs
Authors: Thomas J. Earl
Published: December 2017

The anticholinergic drugs isopropamid iodide (Darbid) and propantheline bromide (Probanthine) were found to decrease the volume, amylase and lipase concentration, and enzyme output in dog's pancreatic juice secreted in response to various stimuli. The volume response to intravenous secretin was affected less than the response to HCl and soap solution in the intestine. This was taken to indicate that the latter two stimuli utilize cholinergic mechanisms not involved in the response to secretin. The volume response to peptone was depressed moderately by the drugs, the enzyme concentration somewhat more. Usually the volume response was depressed proportionately more than the enzyme concentration but always less than the enzyme output.
Effects in vitro of bovine and human antihemophilic globulins on substrate plasmas
Authors: Geisler Philip H. , Eichman Mary F. , Tocantins Leandro M.
Published: December 2017

Greater clot-promoting activity has been claimed for antihemophilic globulin ( AHG) preparations from bovine plasma than for those from normal human plasma. This has been attributed to an actual higher amount of the globulin in bovine plasma. A comparison was made of the effects of bovine and human antihemophilic globulins, collected and prepared in the same manner, on the rate of clotting of not only normal and hemophilic human plasmas but on bovine plasma as well. AHG was prepared from citrated plasma by dilution, acidification, and solution of the washed precipitate in normal saline. While bovine AHG is more effective than human AHG in accelerating the clotting of normal and hemophilic human plasmas, human AHG has a greater effect on bovine plasma than does bovine AHG. Moderate dilution of the plasma substrate enhances the clot-accelerating action of the homologous AHG. The response of a plasma substrate to AHG preparations suggests the presence in plasma of species-specific antagonists which reduce the clot-promoting activity of the homologous AHG, but which are less effective against preparations from heterologous sources.
Effect of certain drugs on cerebrospinal fluid production in the dog
Authors: Oppelt W. W. , Patlak C. S. , Rall D. P.
Published: December 2017

Cerebrospinal fluid (CSF) production rates were measured in the dog by ventriculocisternal perfusion with inulin containing buffer. Normal CSF production rate was found to be about 0.05 ml/min which represents a turnover of 0.4%/min. After intravenous administration of the carbonic anhydrase inhibitors, acetazolamide and methazolamide, a 40–50% decrease in CSF production occurred. An increase in plasma pCO2, by allowing the animals to inhale 95% oxygen, 5% CO2, did not result in any significant change in CSF production. Both intravenous and intrathecal administration of varying doses of the cardiac glycoside, ouabain, did not cause any significant change in CSF production rates. It is concluded that CSF production, in part, is controlled by a carbonic anhydrase system.
Diodrast (I131) whole blood clearance as an index of renal blood flow
Authors: Fozzard Harry A.
Published: December 2017

The whole blood clearance of Diodrast (I131) following a single intravenous injection was used to estimate renal blood flow. This method was compared to renal blood flow simultaneously determined by the PAH constant infusion technique. A correlation coefficient of 0.930 was found. The Diodrast clearance method is recommended because it is simple and rapid, and it avoids the necessity for urine collection.
Effect of cationic amino acid infusion on potassium metabolism in vivo
Authors: Dickerman Herbert W. , Walker W. Gordon
Published: December 2017

The infusion of the cationic amino l-lysine, l-arginine, or l-ornithine into dogs regularly increases potassium excretion to levels that exceed the filtered load of potassium. Hyperkalemia occurs during the amino acid infusion as a result of displacement of the intracellular potassium by the cationic amino acids. This rise in plasma K is not necessary for the stimulation of K secretion since infusion of the lysine directly into the renal artery produces K secretion without significant change in plasma K. This increased potassium excretion is promptly suppressed by the administration of thiomerin. The effects upon renal K handling in these experiments appear to be the result of facilitation of tubular secretion of K rather than inhibition of reabsorption.
Tranquilizer action on thalamic and midbrain escape behavior
Authors: Olds Marianne E. , Hogberg D. , Olds J.
Published: December 2017

Drug tests were made on a behavior pattern which alternated between escape from midbrain stimulation and escape from thalamic stimulation. As the behavior and testing procedures were the same, and as the alternated tests were made intercurrently during the same drug session, the differences in effect depended entirely on the differences between the two points of stimulation. The mesencephalically stimulated escape behavior was regularly far more vulnerable to both chlorpromazine and meprobamate than the thalamically stimulated escape behavior.
Effects of ovariectomy and of hormones on collagenous framework of the uterus
Authors: Cullen Beulah M. , Harkness R. D.
Published: December 2017

Alterations in the size of the collagenous framework of the uterine horns of the rat under different physiological conditions have been examined by mechanical tests in which they were distended in vitro with Locke's solution, containing papaverine to prevent muscular activity, under pressure which was increased progressively until they burst. This framework was found to show large and rapid changes in size related to the endocrine state of the animal. It was larger in estrus and diestrus and reduced by ovariectomy. Its size was increased by relaxin in combination with progesterone and estradiol and by the latter substance alone.
Micropuncture study of renal potassium excretion in the rat
Authors: Malnic Gerhard , Klose Ruth M. , Giebisch Gerhard
Published: December 2017

Samples of proximal and distal tubular fluid were collected from rats maintained on a control, a low-K, or a high-K, low-Na diet. All animals received inulin-C14. Plasma (P) and tubular fluid (TF) were analyzed for Na and K by dual-channel microflame photometry and assayed for radioactivity. Transtubular electrical potential differences were measured by means of glass microelectrodes. Mean TF/P ratios for potassium in the proximal tubule were slightly below unity in all groups of animals. A comparison of the relative increase in K and inulin-C14 along the distal tubule indicates: 1) net movement of potassium into the tubular lumen in most control animals; 2) net movement of K into the tubular lumen of high-K, low-Na, sulfate-loaded animals, and in dichlorphenamide-treated animals on a control diet; and 3) the possibility of continued net reabsorption of potassium along the distal tubule and, particularly, the collecting duct in animals kept on a low-K diet. Distal tubular entry of potassium occurs down an electrochemical potential gradient.
Effects of inhibitors on contractions of normal and dystrophic mouse muscles
Authors: Brust Manfred
Published: December 2017

Exposure to 0.05 mm 2,4-dinitrophenol (DNP), 1 mm NaN3, and 1 mm KCN reveals the following differences between normal and dystrophic excised, curarized gastrocnemius muscles of mice of strain 129. DNP briefly enhances twitch but not tetanus tension in rested dystrophic mice before depressing both tensions. In rested normal mice these tensions decline immediately. NaN3 reduces tensions in rested normal mice for 30 min; slow recovery follows. Half-relaxation rate is also reduced. In rested dystrophic mice tension does not recover from depression in NaN3, and the relaxation rate increases. During fatigue, tension output in dystrophic declines less rapidly than in normal mice, regardless of inhibitors. NaN3 accentuates fatigue-associated increases of contraction rate in dystrophic mice, but accelerates the usual reduction of this rate in normal ones. The two muscle groups also show quantitative differences in their responses to the inhibitors. Except for some DNP effects, all changes are reversible. Known actions of the inhibitors account only inadequately for these observations, and no clearly identifiable metabolic lesions of dystrophic muscles emerge.
Evidence of injury to tissues after hyperthermia
Authors: Burger F. J. , Fuhrman Frederick A.
Published: December 2017

Two criteria of injury by heat were used to ascertain whether hyperthermia produced changes that were detectable in tissues subsequently removed from the animals and incubated at 43 C. These criteria were: decrease in Qo2 below controls and increase in production of ammonia. Pentobarbital and other anesthetics increased the production of ammonia by excised liver and it was therefore necessary to use tissues from animals heated without anesthesia. All experiments were therefore brief, acute, and terminal. Heating rats until there were marked signs of air hunger at rectal temperatures of 43.5– 44.5 C produced a significant increase in the production of ammonia by the excised liver at 43 C. Heating rabbits to a body temperature of 43 C for 1 hr produced a significant decrease in Qo2 of liver at 43 C, compared with controls from unheated rabbits at 38 C, and significant increase in production of ammonia by cerebral cortex at 43 C.
Metabolism and distribution of autologous and homologous albumin-I131 in the dog
Authors: Takeda Y.
Published: December 2017

Using autologous albumin labeled with I131, studies of the metabolism and distribution of plasma albumin were made in 11 healthy dogs maintained in nutritional balance. The average value for the transcapillary transport of plasma albumin ( k1 x) was 2.59 g/day kg; for catabolic rate of plasma albumin ( k3 x), 0.183 g/day kg; for the extravascular albumin ( y), 1.48 g/kg; and for the intravascular albumin ( x), 1.47 g/kg. The estimates of the foregoing with homologous albumin-I131 did not significantly differ. Results are also reported of the passage time distribution of the albumin flux through the interstitial fluids.
Potassium exchange in frog sartorius muscle
Authors: Gourley D. R. H.
Published: December 2017

Under normal conditions, the fibers of frog sartorius muscle contain two K compartments. About two-thirds of the muscle K is in a compartment which readily exchanges with K in the extracellular fluid; the remainder of the muscle K is relatively nonexchangeable. Compartmentalization of the muscle K is not a result of high phosphate or low [K] in the Ringer's solution or previous equilibration at low temperature, but occurs also in vivo. By means of K42, the average muscle K influx and efflux in 2.5 K-Ringer's solution at 20 C were found to be (in µEq g–1 hr–1) 6.41 and 5.81, respectively (different muscles). In the steady state, K moves into the exchangeable compartment of muscle K by a process that can be described by a single exponential equation, but this mechanism fails when the energy stores of the muscle become low. K influx increases with the [K] of the Ringer's solution but reaches a maximum at high external levels of K. It is inferred from these results that the influx of K in frog muscle involves a saturable intermediate, or carrier, system.
Control of aldosterone secretion by change of body potassium in normal man
Authors: Gann Donald S. , Delea Catherine S. , Gill John R. , Thomas J. Picton , Bartter Frederic C.
Published: December 2017

Seven normal subjects were subjected to depletion and repletion of body potassium on balance regimen. Aldosterone excretion, plasma volume, and arterial pressure were measured. Potassium depletion decreased and potassium repletion consistently increased aldosterone excretion. Changes in sodium balance were prevented by restricting dietary sodium or replacing lost sodium. The effects on aldosterone excretion were thus shown to be independent of reciprocal changes in sodium balance of intravascular volume or of arterial pressure. The results suggest that changes in body potassium influence aldosterone secretion by mechanisms independent of those responsive to changes in body sodium or fluid volume.
Effect of sodium lactate on urate clearance in the Dalmatian and in the mongrel
Authors: Reem Gabrielle H. , Vanamee Parker
Published: December 2017

Sodium lactate was infused and urate clearance was measured under conditions of osmotic diuresis alone, as well as during simultaneous urate infusion. Urate clearance in the Dalmatian was not depressed by the administration of sodium lactate of 1.2–9.3 mEq/kg dl-sodium lactate, indicating that sodium lactate has no inhibitory effect on tubular secretion of urate. dl-Sodium lactate, 0.54–11.8 mEq/kg, was administered to four mongrel dogs in five experiments. In three experiments a significant drop of urate clearance in relation to filtration rate was observed. In two experiments in which urine flows exceeded 10 ml/min no significant decrease in urate clearance was recorded following dl-sodium lactate administration. The depression of urate clearance in the mongrel under conditions of moderate urine flow where reabsorption of solutes is more easily accomplished, and the absence of this effect in the Dalmatian as well as in the mongrel under conditions of vigorous diuresis where reabsorption of solutes is greatly diminished, lends support to the belief that sodium lactate depresses urate clearance by facilitating urate reabsorption in the mongrel.
5-Hydroxytryptamine (serotonin) in acute hypotensive shock
Authors: Swank Roy L. , Hissen Wolfgang , Fellman J. H.
Published: December 2017

Alterations in the circulating 5-hydroxytryptamine (5-HT), platelet counts, and the degree of blood cell aggregation were studied before and during acute hypotensive "shock," induced either by bleeding or by histamine injections in anesthetized and heparinized dogs. Although marked aggregation of blood cells was observed during shock only slight increases in 5-HT and platelet counts were found. Since earlier studies in vitro had indicated a direct relationship between aggregation of blood cells and 5-HT the reliability of the fluorometric determination of 5-HT was questioned. Subsequent experiments with C14-labeled 5-HT showed increases up to 600% in circulating radioactivity during hypotension, representing 5-HT, or its metabolites. Radioactivity increased earlier and was greatest in portal blood. Glass-wool filtration experiments showed that adhesive platelets were important in the mechanism of blood cell aggregation. UML-491, a 5-HT and blood aggregation inhibitor in vitro, was shown to prevent or lower the tendency of blood cells to aggregate in vivo during hemorrhage. These experiments indicate the importance of 5-HT in the development of blood cell aggregation during shock, and its prevention by a 5-HT antagonist.
Influence of anterior pituitary on avoidance learning and escape behavior
Authors: De Wied D.
Published: December 2017

Adenohypophysectomized rats were subjected to an avoidance learning procedure. Only 6 of 21 adenohypophysectomized rats achieved the conditioning criterion against 14 of 18 sham-operated controls. The treatment with a long-acting ACTH preparation (ACTH(A1)Zn) during avoidance training resulted in an improvement in the rate of conditioning, which was most optimal following the administration of 1.5 IU. The injection of replacement therapy with cortisone, testosterone, and thyroxine also improved the ability of adenohypophysectomized rats to acquire an avoidance response. The speed with which adenohypophysectomized rats escaped a noxious stimulus in a runway was significantly lower than that of sham-operated controls, indicating that the motor and sensory capacities of this animal were seriously impaired. Administration of ACTH (A1)Zn or of the replacement therapy restored the escape speed toward normal. Accordingly, the deficiency in learning capacity of adenohypophysectomized rats does not seem to depend on the absence of ACTH but on a general debilitation of the adenohypophysectomized organism.
Effect of ionic environment on metabolism and structure of rat kidney slices
Authors: Gordon Edwin E. , Maeir David M.
Published: December 2017

The ionic composition of isoosmotic incubation media exerts a profound effect on the net uptake of glucose, on metabolism of glucose to CO2, and on net water content in rat kidney slices. Substitution of the principal cation, sodium, of the standard incubation medium with potassium, choline, lithium, or guanidine results in characteristic alterations. Sodium is not essential for glucose penetration into the slices. Substitution of the principal anion, chloride, has relatively little effect on metabolism and net water content. A reduction in net glucose uptake and metabolism to CO2 is seen in the high-potassium and choline media. In the potassium medium, there is a striking uptake of water and histological examination reveals marked disruption of tubular cells. In the choline medium, as in the standard medium, there is a net water loss and cellular architecture is well preserved. Under anaerobic conditions, the marked water uptake is partially inhibited in the choline medium.
Chromatographic separation of pepsins from human gastric juice
Authors: Seijffers Max J. , Segal Harry L. , Miller Leon L.
Published: December 2017

Acid gastric juices have been fractionated on DEAE (diethylaminoethyl)-cellulose to yield three pepsin fractions, which have the same chromatographic mobility as the three pepsin fractions previously described in acidified whole gastric mucosal extracts. The acid gastric juices included specimens obtained from healthy individuals and from patients with peptic ulcer and gastritis. Gastric juice from one patient with pernicious anemia was shown to contain only pepsinogen I. A satisfactory chromatographic separation of pepsins is possible from as little as 4 ml of gastric juice.
Hemodynamic response to hypoxia in dogs with chronic pulmonary hypertension
Authors: Kentera Dusan , Wallace Charles R. , Hamilton William F. , Ellison Lois T.
Published: December 2017

Control dogs showed a clear increase in pulmonary resistance, in cardiac output, and in pulmonary arterial pressure when artifically ventilated with 10% O2 under sodium pentobarbital anesthesia. Dogs with pulmonary hypertension from Dirofilariasis showed the same increase in pulmonary arterial resistance but no statistically significant change in pulmonary arterial pressure or in cardiac output when ventilated in the same manner and under the same anesthesia. The anoxia produced a greater lowering of arterial saturation in the hypertensive dogs but this is not enough to explain the clear differences in the response of cardiac output and pulmonary arterial pressure to the anoxic stimulus. It is hypothesized that failure of blood flow and pressure to increase significantly in the hypertensive animals is due to the inability of the chronically overloaded heart to increase its performance in response to anoxia and the accompanying sympathetic stimulation.
Nonuniform distribution of blood flow and gradients of oxygen tension within the heart
Authors: Kirk Edward S. , Honig Carl R.
Published: December 2017

Myocardial tissue pressure increases from epicardium to endocardium, and in the deeper layers exceeds ventricular blood pressure during one-third of the cardiac cycle (21). The effect of this tissue pressure gradient on local blood flow was studied using the depot clearance technique. Blood flow was found to be at least 25% lower in the deep regions as compared with superficial ones. With total coronary inflow held constant, vagal arrest of the heart removed the tissue pressure gradient, and simultaneously redistributed flow from superficial to deeper layers. We conclude that the gradient in tissue pressure, and hence in the extravascular component of coronary resistance, is at least in part, the cause of the nonhomogeneous blood flow across the wall. By use of the oxygen cathode, a gradient of oxygen tensions was observed which paralleled the blood flow gradient; mean oxygen tension in the subepicardium averaged twice that in the subendocardium. The gradient in oxygen tension appears to be of sufficient magnitude to determine a transmural gradient in aerobic metabolism.
Increase in mean circulatory pressure in Goldblatt hypertension
Authors: Richardson Travis Q. , Fermoso Jose D. , Guyton Arthur C.
Published: December 2017

Ten dogs were made hypertensive by the Goldblatt technique. The mean arterial pressure increased from an average control value of 117 mm Hg up to 161 mm Hg. After the animals had become hypertensive, the mean circulatory pressures were measured. These averaged 9.03 (±0.31 SEM) mm Hg, compared with measurements of mean circulatory pressure in ten normal dogs which averaged 7.0 (±0.17 SEM) mm Hg. The increase in mean circulatory pressure was highly significant ( t = 5.75).
Changes in distribution of blood produced by sympathomimetic drugs
Authors: Fell Colin
Published: December 2017

Changes in the distribution of blood produced by sympathomimetic drugs in cats were followed by measuring changes in the distribution of total body weight. Doses of epinephrine and levarterenol (1 µg/kg) produced initial increases in thoracic weights and decreases in abdominal weights, followed by decreases in thoracic weights and increases in abdominal weights significantly beyond control levels. Doses of 8 µg/kg produced responses approximately twice as large, and significant reductions in hindquarter weights. Responses to isopropylarterenol were of doubtful significance, statistically, and were never biphasic. Infusion of drugs at 0.5 µg/kg min produced responses similar to the first phase of responses to 1 µg/kg. Biphasic responses to single doses of epinephrine and levarterenol were seen after sectioning the vagi and carotid sinus nerves. Carotid artery occlusion produced no changes in weight distribution. Responses to epinephrine at 8 µg/kg were estimated to amount to an increase of 11% in thoracic blood content, and decreases of 12, 7, and 9% in blood contents of the head, abdomen, and hindquarters, respectively.
Transplacental passage of gamma globulin-I131 in the rat
Authors: Quinlivan Leslie G.
Published: December 2017

Nineteen rats between the 19th and 21st day of gestation were injected with gamma globulin-I131 after half the feti had been removed from their sacs and the membranes resected to the placental edge. There was no difference at the 1% level between the recovery from the feti with resected membranes and those with intact membranes. Similar results were obtained for three rats in which half the feti were removed from their sacs, the membranes resected, and the vitelline vessels ligated. In three additional rats, half the feti were removed from their sacs, the membranes resected, the vitelline vessels ligated, and the mouths of the feti ligated. The results were again similar. This study shows that gamma globulin-I131 is transferred from the maternal blood stream to the allantoic circulation within the placenta. Passage may or may not be through the trophoblast.
Relationship of input of ACTH to secretion of corticosterone in rats
Authors: Porter John C. , Klaiber M. S.
Published: December 2017

The rate of secretion of corticosterone from the left adrenal during the first 2 hr after hypophysectomy of adult male rats was determined for various rates of infusion of ACTH. The average rate of secretion of corticosterone in the first through the eighth 15-min collection period was 14, 11, 5.6, 2.4, 1.1, .88, .79, and .70 µg/15 min when the infusion rate of ACTH was o µU/min; 8.7, 10, 4.5, 2.1, 1.4, 1.5, 1.3, and 1.2 µg/15 min when the input of ACTH was 26 µU/min; 10, 12, 6.8, 3.5, 3.0, 3.3, 3.1, and 3.0 µg/15 min when the input of ACTH was 52 µU/min; 17, 17, 14, 12, 12, 12, 12, and 11 µg/15 min when the input of ACTH was 78 µU/min; and 17, 20, 18, 16, 15, 15, 15, and 14 µg/15 min when the input of ACTH was 104 µU/min. Sham-hypophysectomized rats secreted 7.1, 12, 15, 17, 16, 16, 15, and 15 µg corticosterone/15 min from the left adrenal in the first through the eighth 15-min collection period.
Relaxing effects of formamide on glycerinated muscle fibers and on myosin B suspension
Authors: Watanabe Shizuo , Maruyama Kosack
Published: December 2017

Acetone induces a reversible relaxation of glycerinated muscle fibers (1). We found that formamide is equally effective. Since the dielectric constant of formamide is larger and that of acetone is smaller than that of water, the change in the dielectric constant of the fiber medium after adding organic solvents has little to do with the mechanism of this organic solvent-induced relaxation. That ITP can substitute for ATP in this relaxation suggests that organic solvents, when they induce a relaxation, act on the contractile protein rather than on ATP. Comparing the relaxing effect of 11 different organic solvents, the authors propose a working hypothesis based on the assumption of a specific interaction between organic solvents and the contractile protein. Formamide induces a "clearing" response of myosin B suspensions which is an in vitro model of muscle relaxation. Effects of Mg, Ca, and ionic strength (KCl) on this clearing response are studied in comparison with the effects of these on EDTA-induced relaxation. It is then shown that the formamide-induced clearing response is less specific than the EDTA-induced clearing response with regard to the requirements for ATP and Mg.
Action current of striated muscle in heavy water
Authors: Jenerick Howard
Published: December 2017

The propagating spike potential of frog sartorius fibers recorded in H2O- and D2O-Ringer's fluids were compared. Negligible changes in the resting, spike, and afterpotential were seen. However, excitability was decreased and apparently caused a slowing of the conduction velocity. A differential effect on the inward and outward current was also observed. Whereas the inward current and conductance appeared completely independent of the solvent, the outward current was quite sensitive to D2O. It was reasoned that such behavior was more indicative of an ion exchange process for the action current in contrast to the conventional mechanism of parallel Na and K conductances.
Equilibration between tissue calcium and injected radiocalcium in the rat
Authors: Mulryan B. J. , Neuman M. W. , Neuman W. F. , Toribara T. Y.
Published: December 2017

The exchange of calcium in soft tissues was studied in normal and slightly hyperparathyroid, adult rats. Both chemical and radiocalcium assays were performed on a variety of tissues at periods from 10 min to 1 hr and also 1 to 4 days after Ca45 injections. Bone, brain, tendon, and muscle were found to exchange quite slowly, requiring from several hours to several days to equilibrate with the circulation. On the other hand, skin, lung, heart, liver, uterus, and kidney showed specific activities equal to or greater than that of the circulating blood within 10 min. Thereafter, the specific activities of these tissues fell rapidly, approximating the rapidly decreasing specific activity of serum. No significant alterations in these patterns were caused by parathyroid extract. The general significance of this rapid exchange of calcium in many soft tissues is discussed.
Fibrinogen breakdown products
Authors: Lewis Jessica H. , Wilson John H.
Published: December 2017

Enzymatic degradation of fibrinogen or fibrin produces two products termed D and E, and perhaps a third E', which have immunological determinates similar to the mother proteins. On electrophoresis (pH 8.6), D remains at the origin and E moves toward the anode. Fibrinogen, but not fibrin, breakdown results in the appearance of a thrombin-fibrinogen clot inhibitor. This inhibitor appears to be identical to fibrinogen-D as both are heat labile and both are found in the same electrophoretic and gel filtration fractions. Fibrin-D is heat stable. Continuous-flow electrophoresis of incoagulable fibrinogen-enzyme mixtures results in the separation of D, E, and a third immunologically similar fragment called E'. Gel filtration suggests that the molecular weight of D is 200,000 or greater and that of E is 100,000 or greater.
Blood pH, O2, and CO2 tensions in exercised control and emphysematous horses
Authors: Gillespie J. R. , Tyler W. S. , Eberly V. E.
Published: December 2017

Horses with clinical signs of spontaneous pulmonary emphysema were demonstrated to have blood-oxygen tensions significantly lower than those of control horses before exercise and declining further with exercise. The pHa of these horses was significantly lower than that of the control horses following exercise, but no difference could be demonstrated in the carbon dioxide tensions of the two groups. The diseased horses showed severe dyspnea with moderate exercise whereas control horses showed few signs of fatigue. The response to exercise of the emphysematous horses varied and probably depended upon the degree and extent of pulmonary pathology present.
Acute effects of ovariectomy on pituitary LH, uterine weight, and vaginal cornification
Authors: Schwartz Neena B.
Published: December 2017

In the cyclic rat, uterine weight increases at proestrus, pituitary LH content drops from a maximum at proestrus to a minimum at estrus, and ovulation and vaginal cornification then occur. To investigate the timing of the ovarian secretion presumably responsible for these changes, ovariectomy or sham ovariectomy was performed at increasing intervals before the day of estrus. Results in both 4- and 5-day cyclers indicate that the ovary must be in situ between diestrus 4 pm (day before proestrus) and proestrus 10 am in order for estrous vaginal cornification to occur; it must be in situ between diestrus 10 am and 4 pm (day before proestrus) for the uterine weight increase and pituitary LH discharge to occur. In some rats sham ovariectomy, when performed at diestrus 10 am, delayed the proestrous-estrous changes by at least 24 hr. The "extra" day which occurs in normal 5-day cycles results at least partly from a delay in the steroid discharge necessary to cause release of the ovulating surge of LH.
Stop-flow analysis of tubular transport of uric acid in rabbits
Authors: Beechwood E. C. , Berndt W. O. , Mudge Gilbert H.
Published: December 2017

Various physiological and pharmacological aspects of the renal handling of uric acid have been investigated. In the majority of rabbits the free-flow urate-to-inulin clearance ratio was found to be less than 1, although some animals (about 20%) demonstrated net secretion. Despite the predominance of net reabsorption under free-flow conditions, the usual stop-flow pattern showed only a proximal secretory peak. No distal tubular activity was evident under any of the experimental circumstances studied. The administration of chlorothiazide, lactic acid, creatinine, or pyrazinoic acid caused a pronounced increase in the proximal secretory peak. Probenecid produced a depression of the secretory peak resulting in a net reabsorptive dip. This reversal of proximal tubular activity is taken as evidence for the presence of both secretory and reabsorptive mechanisms. The following phenomena have been found to be involved in the renal handling of uric acid by the rabbit: 1) filtration of urate at the glomerulus; 2) proximal reabsorptive and secretory transport systems which are drug sensitive; and 3) relative impermeability of the distal tubule to urate.
Acute chloride depletion alkalosis: effect of anions on its maintenance and correction
Authors: Lemieux Guy , Gervais Marc
Published: December 2017

Dogs were made alkalotic and hypochloremic by peritoneal dialysis using an isoosmotic, chloride-free, bicarbonate-rich solution. No potassium deficit was induced by the procedure. Following dialysis, the animals voided large quantities of bicarbonate, sodium, and potassium with partial correction of alkalosis. Subsequently chloride was restricted while sodium and potassium were given as phosphate or sulfate. Plasma bicarbonate rose by 4 mEq/liter while renal excretion of acid increased slightly above control values and sodium was retained. Upon readministration of chloride, retention of chloride and potassium was associated with prompt correction of alkalosis. Chloride space returned to control values while renal excretion of acid did not change. In two experiments, chloride replacement was undertaken during potassium restriction. Again prompt correction of alkalosis was observed while potassium deficit remained unchanged. Renal excretion of acid decreased moderately. The data suggest that the renal tubules are limited in their capacity to reabsorb bicarbonate following acute chloride depletion alkalosis. The administration of impermeant anions favors the maintenance and progression of alkalosis. In the absence of significant reduction in renal excretion of acid, re-expansion of extracellular compartment could be viewed as an important factor in the correction of alkalosis.
Cardiovascular changes associated with thermal polypnea in the chicken
Authors: Whittow G. C. , Sturkie P. D. , Stein G.
Published: December 2017

The effect of hyperthermia on the respiratory rate, cardiac output, blood pressure, arterial hematocrit, and the skin temperatures of the extremities of unanesthetized hens has been investigated. During hyperthermia, the respiratory rate increased to a maximal value and then declined. There was also an increase in cardiac output, followed by a decrease, but the peak cardiac output occurred at a rectal temperature which was significantly higher than that at which the peak respiratory rate was recorded. The increase in cardiac output was the result of an increase in both stroke volume and heart rate. The diminution of cardiac output seemed to be related to a decrease in the stroke volume at high levels of heart rate. The decrease in blood pressure and total peripheral resistance was attributed partly to an increased blood flow through the extremities.