bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of X-Ray Dose on the Protective Action and Persistence of Rat Bone Marrow in Irradiated, Penicillin-Treated Mice
Authors: Santos George W. , Cole Leonard J. , Roan Patricia L.
Published: December 2017

Rat bone marrow cell suspensions injected together with penicillin into mice a few hours following exposure to low lethal (ld20) dose of x-rays (600–680 r) elicited no deleterious effect on percentage of survivors at 30 days, or on mean survival times, when compared to irradiated controls treated with penicillin only. Following ld70–ld100 x-rays (720–770 r), the injection of rat bone marrow plus penicillin resulted in marked increases in percent survival at 30 days, as well as later survival. Thus, at 770 r (ld100), 40% of the treated mice were still alive at 150 days. The single injection of penicillin (3840 u/mouse) together with rat marrow following 870 r exposure, significantly decreased the 30-day mortality, as compared to irradiated mice receiving rat bone marrow alone. In general, rat granulocytes in the peripheral blood, as determined by the alkaline phosphatase histochemical technique, persisted longer at the higher doses of x-radiation. The data indicate that LAf1 mice exposed to x-rays in the midlethal dose range are able to ‘recognize’ and dispose of injected foreign rat cells within a few weeks without suffering an enhanced mortality.
Acute Effect of Organic Binding of Iodine on the Iodide Concentrating Mechanism of the Thyroid Gland
Authors: Wollman Seymour H. , Reed Franklin E.
Published: December 2017

The organic binding of radioiodine by the thyroid gland of the mouse was blocked within 1 minute by the intravenous injection of 1 mg of propylthiouracil (PTU). In mice fed a very low iodine diet the ratio of the radioiodide concentration in the thyroid gland to that in the serum (T/S) was reduced significantly by injection of 1.5 µg of iodide 15 minutes before intravenous PTU injection. The amount of iodine bound prior to PTU injection was only a small percentage of the total iodine in the thyroid gland. This reduction did not occur in mice with less active thyroid glands. However, in the latter mice, doses of 22.5 µg of iodide or more injected 90 minutes before PTU caused a small but systematic decrease in the T/S when compared at fixed serum iodide concentration with mice given PTU before the iodide. In addition, in these mice given both PTU and iodide the T/S was greater than in mice given iodide but no PTU. It is concluded that the organic binding of iodine causes a decrease in the T/S in mice with active thyroid glands. In addition, PTU increases the T/S in mice in which organic binding of iodine is blocked by iodide.
Effect of Low Iron Intake on Hepatic Vasodepressor Material, Plasma Iron and Adrenaline Thresholds of Mesocecal Vessels in Rats
Authors: Crismon J. M. , Dryer Ruth L.
Published: December 2017

Dietary manipulation of iron in rats was accomplished by means of iron-deficient and iron-rich diets. Rats fed the low iron diet developed moderate anemia and had low plasma iron concentrations. Livers from animals kept on low Fe 28–60 days were low in iron content and yielded, under anaerobic incubation, extracts that had none of the vasodepressor effect found in similar extracts from livers of normally fed rats. Rats subsisting on diets containing 2.0 mg of Fe/gm of diet (10 times the Fe of stock ration) had high plasma iron concentrations, high hemoglobin levels and yielded liver extracts with potent vasodepressor action. The iron contents of crude, anaerobic extracts of livers from iron-supplemented rats were higher than those from livers of animals on stock or low iron diets. Vascular beds, in rats kept on low iron diets, had fewer open blood vessels and showed spontaneous vasomotion. Adrenaline thresholds were from 0.12 to 0.20 µg adrenaline/ml while those of the animals on stock diet or iron-supplemented diet were in the normal range, between 0.30 and 0.50 µg/ml. Chronic depletion of iron apparently interfered with the ability of the liver to elaborate or release vasodepressor material under anaerobic conditions; blood vessels of these iron-depleted animals have increased responsiveness to adrenaline as judged from lowered adrenaline thresholds.
Variations in Cardiovascular Sudanophilia With Changes in the Dietary Level of Protein
Authors: Fillios Louis C. , Naito Chikayuki , Andrus Stephen B. , Portman Oscar W. , Martin Robert S.
Published: December 2017

Previous reports indicate that both dietary protein and carbohydrate influence cholesteremia in rats. Therefore, experimentally induced incipient atherosclerosis was studied in rats offered diets containing five different levels of dietary protein. The protein level was altered at the expense of either sucrose or starch. Although there was a greater hypercholesteremia in rats fed sucrose as compared to starch with each level of protein at the end of 3 weeks, this difference was not maintained during the 17-week study. However, inadequate or excessive levels of dietary protein were found to contribute to an increased degree of cardiovascular sudanophilia in both males and females, irrespective of the kind of carbohydrate in the diet.
Function of Ac-Globulin Utilizing TAMe Synthetic Substrate Assay Method For Determination of Prothrombin
Authors: Glueck Helen I.
Published: December 2017

Studies employing a synthetic substrate tosyl arginine methyl ester (TAMe) for the measurement of plasma prothrombin have been utilized to study the function of Ac-globulin. In aged plasmas grossly deficient in this factor, most of the prothrombin initially present in the plasma before storage can be recovered, provided that the thrombin evolving slowly from prothrombin is protected from destruction by antithrombin. The presence of dilute TAMe in the activation mixture appears to perform this function. In stored plasma deficient in Ac-globulin, the efficiency of a specific quantity of accelerator can be increased 10-fold, provided that dilute TAMe, serving to inhibit antithrombin, is present in the activation mixture. Species differences in accelerators, observed with clotting studies, can be largely eliminated, provided that dilute TAMe is present while thrombin is evolving from prothrombin. Experiments with purified prothrombin, free of accelerators and inhibitors, confirm the observations obtained with Ac-globulin-deficient plasma. The activation of purified prothrombin is inhibited by serum. Dilute TAMe effectively blocks this inhibiting effect, allowing for normal activation of the prothrombin. The evidence presented indicates that Ac-globulin acts as a true accelerator, which does not enter into stoichiometric combination with prothrombin.
Movements of Sodium, Potassium and Water in Rat Diaphragm in Vitro
Authors: Rixon R. H. , Stevenson J. A. F.
Published: December 2017

Rat diaphragm was incubated for varying periods in Krebs-Ringer media of different osmolarities and in isotonic sucrose media under oxygen at 37°C and 0°C and under nitrogen at 37°C. The importance of metabolic activity on the regulation of water was reestablished for this tissue. In all conditions studied the movements of water were related to the distribution of Na and K. In isotonic media the water content was directly and linearly related to the sum of Na and K in the tissue: for every change of 35.2 mEq Na + K/kg dry weight there was a parallel movement of 1 gm water/100 gm of wet weight. Incubation in the sucrose media caused an immediate and continuous decrease in water under all metabolic conditions. This evidence indicates that the cell is isosmotic to its normal environment and that the regulation of water in diaphragm tissue is direct and passively related to the regulation of the normal tissue electrolytes, or to the distribution and regulation of the solutes present.
Turnover Rates of Fatty Acids of Plasma Triglyceride, Cholesterol Ester and Phospholipid in the Postabsorptive Dog
Authors: Bates Margaret W.
Published: December 2017

The half-life times of plasma phospholipid and nonphospholipid fatty acids were determined in postabsorptive dogs using C14-carboxyl-labeled palmitic acid. Labeled plasma lipids were introduced into the blood of a recipient dog by cross-circulation with a donor dog that had been fed the radioactive palmitic acid 24 hours previously. Blood samples were taken at various time intervals after the cross-circulation was completed. When the specific activity of the nonphospholipid fatty acids was plotted against time, a semilogarithmic curve was obtained that was resolved into two exponential components with mean half-life times of 22.3 ± 21.9 (S.D.) and 905 ± 182 (S.D.) minutes. A half-life time of 327 ± 81 (S.D.) minutes was found for the phospholipid fatty acids. In one experiment the nonphospholipid fat was further fractionated chromatographically into triglycerides and cholesterol esters. The half-life times of the fatty acids of these two fractions were comparable to the values obtained for the fast and slow components, respectively, found in the preceding experiments. The turnover rate of the triglyceride fatty acids was 1502 ± 505 (S.D.) mg/hr. The rate of appearance of the cholesterol ester fatty acids into the plasma was 29.0 ± 32.7 (S.D.) mg/hr.; the rate of disappearance, 63.4 ± 38.0 (S.D.) mg/hr. A turnover rate of 125.2 ± 49.2 (S.D.) mg/hr. was found for the phospholipid fatty acids in the earlier experiments. The large turnover rate of the plasma triglyceride fatty acids strongly suggests that this fraction is important in the transport of fatty acids in the postabsorptive dog.
Effects of Withdrawal of Growth Hormone and Cortisone Treatment on the Blood Picture of Hypophysectomized Rats
Authors: Gerstner Robert , Gordon Albert S.
Published: December 2017

Peripheral red cell counts of hypophysectomized rats were largely unaffected by chronic treatment with either cortisone or growth (STH) hormone. However, upon withdrawal of treatment, red cell counts tended to rise in the STH-treated rats and to fall in those administered cortisone. The values at this time mirrored the alterations observed in the bone marrows of the treated rats. The postinjection shifts in peripheral red cell numbers were probably the result of oppositely occurring alterations in plasma volume. Leucocytic values induced by prolonged cortisone treatment tended to return to normal levels at approximately 2 weeks after stoppage of injections.
Movement of Substance Proximo-Distally in Nerve Axons as Studied With Spinal Cord Injections of Radioactive Phosphorus
Authors: Ochs Sidney , Burger Emil
Published: December 2017

Small volumes of radioactive phosphorus (P32) were injected into the lumbar 7th (L7) spinal cord of cats by means of fine glass capillaries to study the movement of substance down the motor axons. A gradient of flow over a period of days was indicated when the ventral roots were divided into portions proximal and distal from the cord and each measured for its content of P32 activity. The ratio of P32 activity of the lower to upper portions increased exponentially when plotted as a function of the number of days after injection. The possibilities of a) intra-axonal distal flow following an uptake of P32 by the cell body and dendrite, and b) an adventitious interaxonal (endoneural) distal flow was examined. Activity in the ventral roots was always greater than that in the dorsal roots. The asymmetry supports the concept of an intra-axonic movement since interaxonic flow should be equally possible in the ventral and dorsal roots. A group of animals had the L7 segments of their cords asphyxiated by means of local pressure which destroyed the motoneurons. In these animals, P32 was injected 1 week later. There was a greatly diminished P32 content in the ventral roots of animals so treated when sampled 1 week after injection. This evidence also supports the concept of an intra-axonic movement of substance distally in the axons.
Comparative Study of Blood Volume in Representative Aquatic and Nonaquatic Birds
Authors: Bond Charles F. , Gilbert Perry W.
Published: December 2017

Plasma volume (T-1824 dye method), hematocrit value, hemoglobin concentration and erythrocyte count were measured in several species of aquatic and nonaquatic birds, and from these data total blood and erythrocyte volumes were calculated. Total blood, plasma and erythrocyte volumes, relative to body weight, were greater in aquatic than in nonaquatic birds. Hemoglobin concentration was generally higher in the aquatic group, but pigeons had the highest mean concentration. No significant differences in hematocrit value or erythrocyte count between aquatic and terrestrial birds were observed. Male white leghorns had higher hemoglobin concentrations than hens and male ring-necked pheasants had larger total blood volumes than females, but no other sex differences in blood composition were observed. The essentially identical blood pictures in diving and dabbling ducks indicate that differences in habits of underwater progression between these two groups cannot be explained by differences in blood composition. Of the terrestrial birds studied, the pigeon, a strong flier, had a blood picture comparable to that found in typical aquatic birds. Similar vascular adaptations may suffice for this type of flight and for underwater swimming.
Comparison of Ammonium Sulfate Fractionation of Proteins and of Protein-Bound Mercury in Kidney Soluble Fraction of Chow-Fed and Sucrose-Fed Rats
Authors: Yagi Koichi , White H. L.
Published: December 2017

Most rats fed on sucrose and vitamins for 3 weeks or more survive intravenous injection of mercuric chloride (3 mg/kg), which is uniformly lethal for normal rats. With this increased mercury tolerance a higher percentage of the total kidney mercury is found in the soluble fraction of kidney homogenate. In an attempt to demonstrate qualitative differences in the soluble fraction proteins of sucrose-fed rats as compared with normal, salting-out curves by ammonium sulfate fractionation were obtained. No change in the protein salting-out curves was seen on sucrose feeding, but a shift in protein-bound mercury to the ‘albumin-like’ proteins was observed. The excess soluble fraction mercury of sucrose-fed rats is found in the ‘albumin-like’ proteins. Serial slicing of the kidney showed the mercury largely in the cortex in both types of rat.
Total Capillary Bed in Striated Muscle of Guinea Pigs Native to the Peruvian Mountains
Authors: Valdivia Enrique
Published: December 2017

The total capillary bed in skeletal muscle of guinea pigs has been determined by perfusion with India ink and counting capillaries in cross sections of gelatin embedded muscle. Comparative studies have indicated the importance of age, the muscle studied and the site where counts were performed. Capillaries were more evently distributed in the red than the white areas of the muscle. Free exercise or restriction in cages during the life span did not materially effect the results, although in cross sections some gross enlargement of the red areas was observed in the free exercise group. A significantly greater number of capillaries per square millimeter of muscle tissue were observed in the red area of muscles from animals native to the Peruvian mountains. The red area of these muscles was also more extensive than in the sea level born controls. The possible adaptive significance of these characteristics has been indicated.
Renal Tubular Chloride Reabsorption in the Dog During Rapidly Changing Plasma Chloride Concentration
Authors: Wesson Laurence G.
Published: December 2017

Rates of renal tubular reabsorption of chloride were measured in saline-loaded dogs while plasma chloride concentration was rising or falling. These values were compared with rates of reabsorption measured under conditions of relatively stable plasma concentration. Reabsorption during rising plasma concentration was never more than 3% greater than during stable concentration and usually was not significantly greater. Reabsorption during falling plasma concentration was regularly significantly lower than the stable values by 3–17%, depending upon the rate of concentration fall. When plasma concentration was lowered acutely, approximately 45 minutes were required for depressed rate of reabsorption to return to control levels.
Serum Lipoprotein and Cholesterol Changes in Nephrectomized Dogs Maintained by Peritoneal Dialysis
Authors: Lewis Lena A. , Page Irvine H. , Kolff Willem J.
Published: December 2017

The serum lipoproteins and cholesterol were studied in dogs after bilateral nephrectomy. In most cases the animal's life was prolonged by dialysis. Cholesterol and the lower density lipoproteins increased and remained elevated while the high density –S 1–10 fraction usually decreased moderately. Dogs fed a high protein diet exhibited similar but more pronounced lipid changes and arteriolar necrosis, and no correlation was found between elevation of blood pressure and lipid concentration. Ureteral ligation elicited qualitatively similar lipid changes to arenal dogs fed raw kidneys. As one control, well nourished dogs unfed for 5 days showed no significant serum lipid changes. It is suggested that, by analogy, the postnephrectomy lipid pattern may be in part due to action of products of adrenal cortical stimulation.
Effect of Diet on Rate of Choline Oxidation in the Hyperthyroid Rat
Authors: Boldt R. E. , Harper A. E. , Elvehjem C. A.
Published: December 2017

The rate of choline oxidation by liver homogenates from rats fed diets containing casein plus iodinated casein for 2–3 weeks was markedly lower than that of their euthyroid controls. Feeding pork in place of casein resulted in an increased rate of choline oxidation, although it was still somewhat below the normal level. In vitro addition of large amounts of DPN to liver homogenates from hyperthyroid rats increased the rate of choline oxidation to within the range of the control values. The significance of these results is briefly discussed.
Source of Excess Plasma Cholesterol in Phosphatide-Induced Hypercholesteremia
Authors: Friedman Meyer , Byers Sanford O.
Published: December 2017

To investigate the tissue source of the excess cholesterol appearing in plasma during phosphatide infusion, various tissues of the rat were analyzed for their cholesterol content during phosphatide induced hypercholesteremia. In rats prefed a sterol-free diet, phosphatide-induced hypercholesteremia did not lead to any discernible change in the cholesterol content of any organ or tissue analyzed except liver and adrenal. The cholesterol content of the liver was increased and that of the adrenal, decreased at the height of the induced hypercholesteremia. In rats prefed excess cholesterol, a decline in liver as well as adrenal cholesterol occurred with no discernible change in any other tissue studied. It was postulated that induced hyperphospholipidemia appears capable of mobilizing only stored or excess cholesterol from any tissue.
Effect of Amphenone on Gastric Secretory Activity
Authors: Manrique Jorge , Paredes Raul , Arabehety Julian , Gray Seymour J.
Published: December 2017

A single subcutaneous injection of amphenone to pyloric ligated rats produced a significant decrease in gastric secretory volume, free acid and potassium content, with an increase in pH, gastric juice sodium and pepsin concentration. Cortisone, corticosterone, DCA or ACTH administered with amphenone did not alter the amphenone effect. Aldosterone alone produced a reduction in gastric juice sodium. When amphenone was injected with aldosterone, the amphenone effects, including an increased sodium, were again observed. When amphenone was administered with histamine, the amphenone effects relating to pH and free acid concentration were not observed. Adrenalectomy produced a decrease in gastric secretory volume, acidity and pepsin secretion, and an increase in sodium and pH. In previously adrenalectomized rats the amphenone inhibitory effects on gastric secretion were absent. An increase in adrenal gland weight was observed 4 hours after amphenone administration, but was not seen when cortisone, corticosterone, DCA, aldosterone or histamine were administered with amphenone. ACTH alone or with amphenone produced an increase in adrenal weight. Amphenone caused a considerable increase in thymus weight, which could be prevented by the simultaneous injection of corticosterone, aldosterone or histamine, but not by DCA or adrenalectomy. ACTH or cortisone alone or in combination with amphenone decreased thymus weight.
High Energy Phosphates During Hibernation and Arousal in the Ground Squirrel
Authors: Zimny Marilyn L. , Gregory Roy
Published: December 2017

Biochemical levels of inorganic phosphate, adenosine triphosphate, phosphocreatine and glycogen were determined on cardiac muscle, skeletal muscle and liver samples from hibernated 13-striped ground squirrels and those allowed to awaken for intervals of 7.5, 15 and 30 minutes. Cardiac muscle glycogen increases during hibernation apparently at the expense of skeletal muscle and liver glycogen. Glycolysis occurs in these tissues during early arousal, followed later by glycogenesis. Adenosine triphosphate is maintained in both cardiac and skeletal muscle during hibernation and is used as an energy source during arousal. It appears that glycolysis is important in resynthesizing phosphocreatine. From this study of periods of relatively low and high metabolic demands we conclude that phosphocreatine is a ‘transport’ form of high-energy phosphate forming adenosine triphosphate from the phosphate pool when and where needed in the cycle of intermediary metabolism.
Ventricular ‘Echoes’
Authors: Rosenblueth Arturo
Published: December 2017

In dogs anesthetized with pentobarbital, with the heart denervated; the adrenals ligated, and the S.A. node crushed, stimuli were applied to the ventricle. Whenever the V-A delay lengthens sufficiently there is an additional ventricular impulse that returns from the auricle; these impulses are designated as ‘echoes.’ If the stimulated ventricular impulse is blocked before reaching the auricle no echo ensues. The V-A lengthenings were obtained by stimulation at appropriate rates, by the application of pairs of stimuli with short delays, and by vagal stimulation. Adrenaline may cancel echoes by shortening the V-A interval. Ventricular or auricular stimulation may give rise to automatic discharges of the A.V. node. Echoes are not automatic discharges. They are similar to the ‘re-entrant’ or ‘reciprocating’ discharges. The hypothesis usually accepted for the mechanism of these discharges is shown to fail to account for the time relations between the ventricular and auricular impulses in the responses followed by echoes. An alternative explanation is suggested, based on the hypothesis that A-V and V-A propagation follow different paths.
Competition Between Human Plasma Albumin and Globulins for Estradiol and Sodium Estrone Sulfate
Authors: Bischoff Fritz , Turner John G. , Bryson George
Published: December 2017

Equilibrium ratio determinations of estradiol and sodium estrone sulfate distributed between human red cells and solutions of human plasma albumin, fraction IV-1, or fraction IV-4 of Cohn were made at 38°C and ionic strength of 0.155. The albumin contents of the IV-1 and IV-4 fractions were analyzed by 26% sodium sulfate fractionation. When the influence of the albumin in fractions IV-1 and IV-4 was estimated on the basis of the performance of pure albumin solution, the influence of the globulins was small even on a molar basis. The red cell:albumin ratio, using a physiologic albumin concentration, was nearly the same as the endogenous ratio previously obtained for last trimester human red cells: serum. It is concluded that albumin is responsible for 90% or more of the orientation in human plasma of the estrogens studied.
Effect of Sodium Intake Level on Hypertensive Disease in Rats
Authors: Sturtevant F. M.
Published: December 2017

A group of metacorticoid (post-DCA) hypertensive rats drinking normal saline was compared to a group drinking tap water over a period of 44 weeks. The two groups did not differ appreciably in their blood pressures or survival rates. When the tap water group was offered only saline 1 day a month, the rats tended on the average to have lower intakes and outputs of sodium and water than the rats accustomed to drinking saline.
Role of Food Consumption in the Mortality Response of Irradiated Rats Subjected to Prolonged Cold Exposure
Authors: Newsom Bernard D. , Kimeldorf Donald J.
Published: December 2017

Prolonged exposure to a low ambient temperature increases the 30-day mortality rate of irradiated rats. To determine if the increased mortality is due to a failure of the irradiated rat to adapt to the higher metabolic demands of a cold environment, the food consumption of irradiated (500r, 600r, 250 kv x-rays) animals was measured during 30 days of exposure at normal (23°C) or lowered (6°C) environmental temperature. The food consumption of irradiated animals was increased by exposure to cold; however, this increase was not sufficient to maintain body weight at a level comparable to nonirradiated animals. When the food consumption of nonirradiated animals was limited to that of irradiated animals during exposure to a 6°C environment, the mortality observed among nonirradiated animals was comparable to the increase in mortality induced by cold exposure of irradiated animals. These results suggest that the increased mortality rate of irradiated animals in a cold environment is related to an inadequate food intake.
Surface Activation of Guinea Pig Ventricle Determined by Intracellular Electrodes
Authors: Dower Gordon E. , Osborne John A.
Published: December 2017

Intracellular micro-electrodes have been used to detect the arrival of the activation process in myocardial fibers lying near the epicardial surface of the intact guinea pig ventricle. Arrival of excitation was indicated by the steepest part of the upstroke of the transmembrane action-potential curve obtained. The times of arrival of the activation process at various points on the surface of the ventricles were measured with respect to selected points on the simultaneous ECG, which served as a standard of reference. The scale on the time axis was greatly magnified (paper speed = 75 cm/sec.) in order to determine these times with precision. The ‘relative activation times’ thus obtained indicated that the right ventricle tended to be activated earlier than the left, except on their dorsal aspects, where there was little difference. There were, however, many exceptions to this general pattern, and rather large differences in relative activation times were frequently observed between contiguous regions. The high paper speeds used revealed three different types of upstroke in the monophasic records. An association was observed between the relative activation time of a region and the type of upstroke. An explanation of these findings is offered and a supporting experiment described.
Effect of Anesthetization of A-V Node on Ventricular Fibrillation Following Acute Coronary Arterial Occlusion
Authors: Webb Watts R. , Field S. E.
Published: December 2017

Anesthetization of the A-V node with procaine to produce complete atrioventricular dissociation was found to reduce the incidence of ventricular fibrillation following left coronary artery ligation, which in all control animals resulted in ventricular fibrillation in less than 150 seconds. Of 14 dogs in which idioventricular rhythms were produced, three fibrillated at 30 seconds, 7 minutes and 18 minutes, respectively, while the remaining 11 hearts gradually slowed and stopped after periods up to 45 minutes without fibrillation or other arrhythmia. Of the two dogs which developed an atrioventricular nodal rhythm following procainization, one fibrillated at 9 minutes after coronary ligation, while the other gradually slowed to asystole in 11 minutes.
Effect of Interruption of Coronary Circulation on Metabolism of the Arrested Heart
Authors: Michal G. , Beuren A. , Hogancamp C. E. , Bing R. J.
Published: December 2017

The experiments deal with the effect of complete myocardial anoxia on the oxygen usage and carbohydrate metabolism of the heart. Work was performed on heart muscle slices and on the whole heart in the closed chest dog. In experiments on the whole heart, arrest of the coronary circulation resulted in a gradual decline in myocardial oxygen usage after 2 hours. After 4 hours, the myocardial oxygen usage was negligible. Severe alterations in carbohydrate metabolism were observed, such as a significant increase in myocardial lactate production. In experiments on tissue slices, myocardial oxygen usage declined more rapidly. After 1 hour, only 40% of the initial Qo2 remained. Aerobic glycolysis takes place in heart muscle slices as indicated by a significant increase in the RQ of this preparation.
Failure of Change in Extracellular Volume to Alter Plasma Potassium Concentration
Authors: Scribner Belding H. , Kleinberg Henry , Burnell James M.
Published: December 2017

Changes in the plasma potassium concentration have been attributed to changes in extracellular space volume. The extracellular space of dogs was increased by 53%; the plasma potassium concentration fell only during the transient disequilibrium state. It is concluded that the plasma potassium concentration is independent of the size of the extracellular space.
Filtration Coefficient of the Capillaries of the Brain
Authors: Coulter N. A.
Published: December 2017

The Monro-Kellie doctrine was used as the basis for determination of the filtration coefficient of the capillaries of the cat's brain. An average value of 10.3 x 10–8 ml/sec/cm H2O/cm2 was found. A linear relation was observed between filtration rate and filtration pressure. The fact that the filtration coefficient of brain capillaries is somewhat higher than that of muscle capillaries suggests that lipoid insoluble molecules actually penetrate the brain capillary membranes readily, but are pumped back by a secretory process.
Binding and Transport of Serotonin in Rabbit Blood Platelets and Action of Reserpine
Authors: Sano I. , Kakimoto Y. , Taniguchi K.
Published: December 2017

Evidence for the occurrence of bound serotonin was not demonstrated by various physicochemical procedures using rabbit blood platelets. Thus, when serotonin was separated completely from the platelet proteins, the ultrafiltrate of a platelet homogenate contained the same concentration of serotonin as the unfiltered homogenate and, at equilibrium after dialysis of the platelet homogenate, the concentration of serotonin outside the bag was practically equal to that on the inside. The absorption of serotonin by platelets was stimulated by glucose and this stimulation was inhibited by inhibitors of glucose oxidation and by an uncoupler of oxidative phosphorylation. ATP seemed to be the principal substance stimulating absorption. Reserpine inhibited the absorption stimulated by glucose or ATP. The mechanism of the transport and release are discussed and it is suggested that enzymatic processes may participate in both reactions.
Single Proximal Tubules of the Necturus Kidney. Methods for Micropuncture and Microperfusion
Authors: Shipp Joseph C. , Hanenson Irwin B. , Windhager Erich E. , Schatzmann Hans J. , Whittembury Guillermo , Yoshimura Hisato , Solomon A. K.
Published: December 2017

Procedures for the collection of tubular fluid and for stopped flow perfusions of the single proximal tubule of the kidney of Necturus maculosus are described. The method used in collection experiments is essentially the same as that developed by Richards and Walker ( Am. J. Physiol. 118: 111, 1937). The method used for stopped flow perfusion is a modification of the method of these authors. A proximal tubule in vivo is blocked with oil at both ends and the intervening space is filled with a perfusion fluid. After a suitable period (for instance, 20 min.), the fluid is withdrawn. By this method perfusion fluids of any desired composition are allowed to remain within the tubular lumen for an arbitrary period of time prior to collection and analysis. Water movement in the tubule is measured using C14 inulin. 27 samples of ureteral urine collected from 10 animals had a Na concentration of 2.8 ± 1.7 mEq/l. Data on the electrolyte composition of Necturus blood are presented, consistent with values given by other authors.
Distribution of Injected Adrenaline and Noradrenaline in Plasma and Muscle of the Rat
Authors: Taylor Joan N.
Published: December 2017

The Weil-Malherbe and Bone fluorimetric method of determining adrenaline and noradrenaline was adapted for measuring these hormones in small samples of blood plasma and muscle in the rat. The endogenous levels of adrenaline and noradrenaline, respectively, for rat plasma are 6.7 ± 0.08 and 17.7 ± 0.06 µg/l.; for the rectus femoris muscle 0.020 ± 0.002 and 0.149 ± 0.011 µg/gm tissue. Ten micrograms l-adrenaline and 20 µg d,l-noradrenaline/100 gm body weight were injected intraperitoneally, and plasma and muscle samples analyzed for these hormones at timed intervals thereafter. The injection of adrenaline effects a prompt increase in both plasma and muscle noradrenaline; a significant increase in adrenaline level was found 6 minutes after injection in the plasma, and at 60 minutes in the muscle tissue. A return to initial levels occurred at approximately 10 minutes and 90 minutes, respectively. The injection of noradrenaline resulted in an immediate increase in the plasma and muscle levels of this hormone; coincidently the adrenaline levels remained relatively unchanged.
Effect of DL-Ethionine and S-Ethyl-L-Cysteine on Rat Liver Regeneration
Authors: Gershbein Leon L.
Published: December 2017

The administration of diets containing 0.05–0.40% dl-ethionine to partially hepatectomized rats decreases the extent of liver regeneration over a period of 10.5 days. Body weight losses and definite liver pathology are noted for animals of either sex fed the rations with 0.30% or 0.40% ethionine. The effect is neutralized by the simultaneous feeding of methionine but not by choline, thereby reflecting definite amino acid antagonism. S-ethyl-l-cysteine, a homolog of ethionine, at a dietary level of 0.40% is without effect on the rate of liver regeneration.
Effect of Adrenocortical and Hypophyseal Hormones on Uptake of Fat by Isolated Perfused Liver
Authors: Heimberg Murray , Meng H. C. , Bradley D.
Published: December 2017

The effect of adrenocortical and anterior pituitary hormones on the uptake of neutral fat by the perfused rat liver has been investigated. It was observed that adrenalectomy increased the rate of fat uptake. Cortisone treatment of adrenalectomized animals reduced the rate of fat uptake to that of the normal fed state. Cortisone and hydrocortisone administered in vivo, or added to the perfusion fluid in vitro, reduced the rapid rate of fat uptake resulting from 48 hours of fasting. Hydrocortisone administered to normal fed rats did not depress the rate of fat uptake. The administration of crude anterior pituitary extracts to the normal fed animal significantly increased fat uptake. Hypophysectomy increased the rate of fat uptake. Administration of growth hormone to the normal fed animal 3–8 hours prior to killing, or added to perfusion fluid in vitro, increased the rate of fat uptake.
Anti-Inflammatory Effects of Counterirritants
Authors: Laden C. , Blackwell R. Quentin , Fosdick L. S.
Published: December 2017

Experimental inflammatory edema was induced by injecting an irritant solution into the pleural cavity of rats. The volume of fluid found in the pleural cavity after a specified time interval was used as a measure of the degree of inflammation produced. The effect of counterirritants on reducing pleural inflammation was studied. Injection of irritants into the knee joint of the rat was found to reduce the amount of pleural inflammation formed. The anti-inflammatory effect observed could not be explained by loss of fluid into the injected knee, nor by stimulation of the pituitary-adrenal axis. The effect was still present in hypophysectomized rats and adrenalectomized rats. The use of plaster casts to prevent fluid loss into the injected leg did not block the reduction in pleural inflammation. It was suggested that counterirritants release some substance or substances from the tissues which they damage, which is carried by the blood and can exert an anti-inflammatory effect in another part of the animal.
Metabolic Responses to Thermal Stressors of Altitude-Acclimated Rats
Authors: Hale Henry B. , Mefferd Roy B.
Published: December 2017

Fasting 24-hour exposures of altitude-acclimated rats (380 mm Hg, 18,000 ft. simulated) to ground level pressure (750 mm Hg) at either cold (3°C), neutral (24°C), or hot (35°C) temperatures seldom resulted in return of their metabolic functions to preacclimative ‘normalcy.’ Although the control and altitude-acclimated groups both were accustomed to neutral temperatures (24° and 26°C), quantitative differences at ground level and altitude occurred in various indices of water, mineral and nitrogen metabolism. Of the 32 physiologic variables studied, only 4 (ratio of urine volume/ water intake, and urinary excretion of potassium, creatinine and glycine) failed to differentiate the responses of the altitude- and ground-accustomed rats. The temperature response curves of the altitude group tended to parallel the corresponding ones for the control group, but most variables were on higher or lower planes. The difference in plane resulted either from the effects of the return to ground level pressure, or from nonreversible effects of acclimation to altitude per se.
Whole Body Lipid Metabolism of Rats After Chronic Exposure To Adverse Environments
Authors: Mefferd Roy B. , Nyman M. A. , Webster W. W.
Published: December 2017

Specific activities of the total nonsaponifiable lipids, cholestrol, total fatty acids, solid fatty acids and liquid fatty acids, and the liver succinic dehydrogenase activities were determined for adult male Sherman strain rats following chronic exposure (2 months) to cold (2°C), neutral (24°C), or hot (35°C) environments or to discontinuous (4 hr. daily) simulated altitude (18,000 ft., 24°C). By all indices lipid metabolism was elevated in the cold, and by most it was depressed in the heat and altitude. In the latter, however, succinic dehydrogenase activity was elevated. Cholesterol, liquid fatty acids, succinic dehydrogenase activity and the cholesterol/total nonsaponifiable lipid ratios decreased linearly with temperature. The solid/liquid fatty acids ratio was elevated in the heat. The solid fatty acid/cholesterol ratio was temperature independent but was depressed in the altitude group.
Chylomicron Metabolism: Alterations of Absorbed Labeled Lipid
Authors: Burr William W. , McPherson James C. , Tidwell Herbert C.
Published: December 2017

Palmitic acid-1-C14 in olive oil was fed to rats, and after absorptive periods of 1 1/2, 4 and 5 hours the animals were exsanguinated. Chylomicron-free plasma or blood diluted with urea solution was prepared by high speed centrifugation. Radioactive assay of the plasma or diluted blood before and after centrifugation indicates that an increasing percentage of the total radioactivity no longer resides in the chylomicrons. When particulate-free plasma was subjected to trichloroacetic acid precipitation, between 71 and 95% of the radioactivity was in the precipitate. Attempts to extract the lipids from the precipitate demonstrated that only a portion of the radioactivity resided in the lipid fraction. The relationships of these observations to the current concepts of lipid transport are discussed.
Effect of growth hormone on carbohydrate metabolism in normal and hypophysectomized dogs; studies with C14 glucose
Authors: Altszuler N. , Steele R. , Wall J. S. , Dunn A. , de Bodo R. C.
Published: December 2017

Using trace amounts of C14 glucose, introduced intravenously by a priming injection along with a continuous constant infusion, the effect of a growth hormone regimen on the size of body glucose pool and on the rate of glucose utilization as well as production was studied in unanesthetized normal and hypophysectomized dogs. In both types of animals the growth hormone regimen increased the size of the body glucose pool. More significantly the growth hormone regimen increased the rate of glucose utilization as well as the rate of glucose production. It is proposed that the inhibitory effect of injected growth hormone on glucose uptake observed in isolated diaphragm is overcome in vivo by an increased endogenous insulin secretion evoked by the extra glucose produced as a result of the growth hormone treatment.
Relationship of adrenocortical and anterior pituitary function to fecal excretion of sodium and potassium
Authors: Davis James O. , Ball Wilmot C. , Bahn Robert C. , Goodkind M. Jay
Published: December 2017

The relationship of aldosterone excretion in urine to Na and K output in feces was studied. In dogs with thoracic inferior vena cava constriction and ascites, a high rate of urinary aldosterone output was associated with a very low fecal Na/K excretion. Following bilateral adrenalectomy and in the absence of hormone therapy, aldosterone was no longer detectable in urine and fecal electrolyte excretion returned to within normal limits. Hypophysectomy of dogs with thoracic caval constriction and ascites was followed by a decrease in urinary aldosterone and a concurrent rise toward or to normal of the fecal Na/K ratio. The data suggest that increased circulating aldosterone influences the intestinal mucosal transport of Na and K. Also, the effects of hypophysectomy on fecal electrolyte and renal Na excretion were observed in otherwise normal dogs. Fecal Na and K excretion increased following hypophysectomy in the majority of these animals; the increase in fecal Na output was progressive and more pronounced than that in fecal K excretion. Renal Na excretion was low during the early posthypophysectomy period but, subsequently, increased sufficiently for Na balance to be achieved in all but one dog.
Ventricular coupling induced by anodal or cathodal polarization during continuous direct currents in dog ventricle
Authors: Walker Sheppard M.
Published: December 2017

Ventricular ectopic beats coupled with preceding normal beats occur during the delivery of direct current when the anode or cathode is on the ventricular epicardium of the dog. These ectopic beats are induced within the T-wave or immediately thereafter during the application of threshold direct current when the anode is on the epicardium. When anodal current is begun in the ST segment of a given cycle, an ectopic beat is induced within or near the T-wave of the same cycle. When the cathode is on the epicardium, coupled ventricular ectopic beats are induced within the PR interval during the application of threshold direct current. Under these conditions marked slowing of sinus rate by vagal stimulation does not alter the interval of coupling between the ectopic beat and the preceding normal beat. Thus it is shown that the abnormal ventricular beat, falling within the PR interval, is ectopic and independent of the auricular impulse.
Electrical and mechanical responses of uterine smooth muscle during anaphylaxis in vitro
Authors: Katsh Seymour , Marshall Jean M.
Published: December 2017

Female guinea pigs were injected with antigen (homologous sperm or ovalbumin) and 14–28 days later ileal segments and both uterine horns were removed. The ileal segments and one of the uterine horns from each animal were tested for responses to drugs, as well as to nonspecific and specific antigen; responses were recorded by means of a kymograph and muscle lever. The contralateral cornua were tested with nonspecific and with specific antigen as well as with drugs; responses were detected and recorded with intracellular electrodes and a mechanotransducer. The notable findings relative to the electronic studies were: within 1–2 minutes following exposure of the sensitized uterus to specific antigen there occurred a) a diminution in resting membrane potential; b) a sudden burst of action potential spikes; c) a contraction of the musculature which was of greater amplitude and of longer duration than those of the spontaneous contractions; d) during the sustained contracture phase, the rate of discharge of action potential spikes was higher than that accompanying spontaneous contractions. After desensitization, specific antigen was without effect. No effect of nonspecific antigen was observed in any of the preparations. After stimulating with specific antigen or with drugs, additional action potentials arose before repolarization from the previous action potential was completed.
Transport of p-aminohippurate from cell to lumen in kidney tubule
Authors: Foulkes Ernest C. , Miller Benjamin F.
Published: December 2017

Intracellular accumulation of various anions in the rabbit kidney tubule has been well documented. The present experiments were designed to test the hypothesis that in the rabbit no further concentration step is required for the transfer of these materials from the cells into the tubular lumen. In such a case PAH should be accumulated in the cells to the same concentration as in the proximal tubular urine. The maximum active uptake in vivo was determined by measurement of intracellular PAH in kidney cortex rapidly removed from freshly killed animals with high plasma levels of PAH. A value of about 10 µmoles/ml cell water was obtained. The concentration of PAH in the tubular urine was estimated during massive osmotic diuresis on the assumption that bladder urine under these conditions approaches proximal tubular urine in composition. With simultaneous PAH and mannitol loading, a PAH concentration not exceeding 10 µmoles/ml proximal tubular urine was observed. The same value was calculated from results obtained by the stop-flow technique.
Steps in p-aminohippurate transport by kidney slices
Authors: Foulkes Ernest C. , Miller Benjamin F.
Published: December 2017

The existence of two intracellular fractions of PAH was demonstrated in renal cortical slices of the rabbit on incubation with C14-labeled PAH. One of these fractions is rapidly diffusible and rapidly equilibrates with extracellular PAH. The other fraction, in contrast, diffuses and equilibrates slowly; it is responsible for the high slice to medium concentration ratio of PAH. On the basis of these results a model of the PAH transport system in slices is proposed. This consists of step I, the diffusion of PAH from the medium into the extracellular space in the tissue; there follows step II, a facilitated diffusion step at the peritubular cell membrane; within the cell step III builds up a high tissue concentration of PAH; finally step IV transfers PAH across the luminal border of the cell into the tubular lumen from which it may diffuse back into the medium. Experiments were designed in which each of these steps could be measured individually and their rate constants determined. Alteration of the value of these rate constants by specific drugs localizes the action of such compounds at the peritubular cell membrane (Benemid, 9-alphafluorohydrocortisone) or at the level of both steps II and III in the case of DNP, octanoate and Diodrast. An explanation is also offered for the effect of cold on PAH influx and efflux. It can be calculated that the contribution of step IV to the turnover of PAH in slices is not quantitatively significant.
A method for simultaneous catheterization of major hepatic vessels in a chronic canine preparation
Authors: Shoemaker William C. , Walker William F. , Van Itallie Theodore B. , Moore Francis D.
Published: December 2017

A feasible method for measuring concentration changes of various substances as they enter and leave the liver is described together with the operative technique. This preparation allows simultaneous sampling of blood from all major hepatic vessels in the in vivo, unanesthetized dog under chronic experimental conditions. A modification of this technique is described whereby liver biopsies may be obtained at the same time as the blood sampling.