bluuebunny/crossref_metadata_2025 huggingface dataset:
Homograft-reactive large mononuclear leucocytes in peripheral blood and peritoneal exudates
Authors: Cole Leonard J. , Garver Richard M.
Published: December 2017

Two criteria have been employed for demonstrating the presence of homograft-reactive cells in peripheral blood and peritoneal exudates: a) production of a lethal wasting syndrome in sublethally x-irradiated (500 r) (LxA)F1 hybrid mice following injection of cells from parental strain (A-strain) donor mice; b) abrogation of protection by injected bone marrow in lethally x-irradiated mice by these cells. Injection of 8 x 106 peritoneal exudate granulocytes does not elicit the wasting syndrome, whereas 2.1 x 106 mononuclear cells obtained from peritoneal exudates 8 days after mineral oil administration are reactive. When peritoneal mononuclear cells from isoimmunized A-strain donors were administered, reactivity of cells was enhanced. Prior treatment of A-strain donor mice with cortisone did not abolish homograft reactivity of injected blood (1.1 x 106 nucleated cells). Under these conditions of cortisone treatment, there was a relative increase in frequency of large mononuclear cells (9 µ diameter or larger), disappearance of essentially all small lymphocytes (5 µ diameter). Data are presented that indicate the capacity of large mononuclear cells in peripheral blood to transform into cells of plasma cell series. It is concluded that circulating blood contains a mobile pool of large mononuclear cells capable of division, and potentially able to initiate immunological reactions, i.e. homograft reactions, analogous to that possessed by lymphoid tissue cells.
Metabolic rate and lipogenesis in weanling rats fed high carbohydrate diets
Authors: Heggeness F. W.
Published: December 2017

Weanling rats fed a 60% carbohydrate diet were observed to have a self-limiting elevation in oxygen consumption persisting for 6–9 days. This phenomenon was associated with a diminished food utilization during this interval. The calorigenic response was abolished by feeding the 60% carbohydrate diet in amounts just sufficient to maintain body weight for several days before ad libitum ingestion was permitted. Animals so treated develop some type of adaptation and are referred to as adapted animals. Further studies of this metabolic response were carried out on rats fed the high carbohydrate diet ad libitum at weaning and in other animals after such a period of adaptation. Unadapted weanling rats fed 60% carbohydrate diets ingest calories in excess of their capacity for efficient utilization. During ad libitum feeding, adapted animals were found to accumulate fat at a faster rate than unadapted animals. The evidence obtained is consistent with the conclusion that in the weanling rat lipogenesis is below achievable limits and becomes limiting with regard to food utilization when a high carbohydrate diet is fed. The calorigenic response appears to dissipate ingested calories above those utilizable for energy, including weight gain, and thus maintain a balance between caloric intake and expenditure.
State of oxidation of nonprotein sulfhydryl compounds in vitamin B12 deficiency
Authors: O'Dell B. L. , Erickson B. A. , Newberne P. M. , Flynn L. M.
Published: December 2017

A vitamin B12 deficiency in weanling rats, which reduced their average weight to one-half that of controls, decreased liver concentration of nonprotein sulfhydryl (NPSH) compounds about 10% but had no effect on concentration of disulfide compounds. Fasting did not accentuate the effect of the deficiency. Dams severely depleted of B12 produced offspring whose livers contained significantly less NPSH and correspondingly more nonprotein disulfide (NPSS) compounds than controls. Thus the decreased concentration of NPSH on the B12-deficient liver was accounted for as NPSS. Vitamin B12 deficiency had no effect on the rate of anaerobic glycolysis in liver and brain tissues.
Iodopyracet (Diodrast) transport by the rabbit eye
Authors: Becker Bernard , Forbes Max
Published: December 2017

Iodopyracet is accumulated by the rabbit ciliary body in vitro and transported out of the living rabbit eye. Both processes resemble the analogous accumulation and active transport by the renal tubules and demonstrate similar competitive and metabolic inhibition. With increasing amounts of iodopyracet in the eye, saturation of the secretory system is demonstrated with a secretory maximum of approximately 1.2 x 10–8 moles/min.
Blood volume changes in rodents exposed to simulated high altitude
Authors: Anthony Adam , Kreider Judy
Published: December 2017

Blood volume measurements were made in rats and mice exposed to a simulated altitude of 20,000– 22,000 ft. for periods of 1–4 weeks. The noncapillary blood volume (which includes arteries, veins, arterioles and venules) was determined from plastic-corrosion preparations of the circulatory system. The plasma volume and total blood volume were measured using the T-1824 dye dilution method and capillary volume was calculated by subtracting noncapillary volume from total blood values. The increase in volume of the noncapillary vessels of rats and mice was about 1–2 ml/100 gm body weight after 1–4 weeks of altitude exposure. It was also shown that the total blood volume of acclimatized rats is about 40% greater than that of control animals whereas the plasma volume decreases by about 57%. It was concluded that altitude exposure resulted in a greater increase in the capacity of the noncapillary vessels ( ca. 60%) than in that of the capillary bed ( ca. 25%).
Liver injury in isolated perfused rat liver preparation exposed to chloroform
Authors: Brauer R. W. , Leong G. F. , Holloway R. J.
Published: December 2017

Exposure of the isolated rat liver preparation to CHCl3 at concentrations of 0.016–0.056 mg/l. O2/CO2 results in decreased bile flow, increased glucose concentrations in the perfusate, increased tissue sodium space and early histological changes similar to those seen in vivo. These changes are associated with slight vasodilatation and increased rates of blood flow through the liver. Withdrawal of CHCl3 does not result in reversal of any of the above changes except for the vasodilatation over a period of 3 hours after termination of the chloroform exposure. The effect of differences in CHCl3 dosage is presented. The data are interpreted as a) confirming the view that a biochemical lesion rather than circulatory events initiates the chloroform injury to the liver and b) underscoring the vulnerability of the tissue during the protracted period of recovery from the damage inflicted by this agent.
Interaction of central and peripheral factors in physiological temperature regulation
Authors: Fusco M. M. , Hardy J. D. , Hammel H. T.
Published: December 2017

To evaluate the relative importance of central and peripheral factors in physiological temperature regulation, calorimetric measurements of thermal and metabolic responses in the unanesthetized dog to localized heating of the supraoptic and preoptic regions were made at various environmental temperatures. At all temperatures, heating the hypothalamus caused an imbalance in the over-all heat exchange, and lowered core temperature by 0.8°–1.0°C. In a neutral environment, this was effected by a 30–40% depression of the resting rate of heat production. In a cool environment, heating inhibited shivering so that heat production, relative to heat loss, was low. In a warm environment, vigorous panting and vasodilatation were elicited, thereby increasing heat loss. On cessation of heating, shivering occurred in response to the lowered core temperature, but differed in intensity depending upon the peripheral thermal drive. Reapplication of heating suppressed shivering in all cases. From these data some quantitative estimates were made of the sensitivity of the hypothalamic thermoregulatory ‘centers’, and of the interaction and relative contributions of central and peripheral control.
pCO2 in regulating ammonia excretion by renal tubules of dogs
Authors: Cade Robert , Shalhoub Robert J. , Hierholzer Klaus
Published: December 2017

The importance of urine pH, urine flow, availability of substrate and activity of cellular enzymes on the production and excretion of ammonia have been investigated in several species. Little information concerning the effect of intracellular pH on ammonia excretion is available. To investigate this problem we have altered intracellular pH by inducing respiratory acidosis and alkalosis in dogs. An elevated pCO2 uniformly depresses excretion of ammonia while a fall in pCO2 is associated with increased ammonia excretion at any given urine pH. When animals are depleted of potassium, the degree of depression by 10% CO2 is far greater than in the same animals studied before potassium depletion. The data are interpreted in the context of the passive diffusion theory of ammonia transport.
Spreading depression using chronically implanted electrodes
Authors: Ochs S. , Hunt K. , Booker H.
Published: December 2017

Spreading depression (SD) was elicited from the cortex of rabbits in which an electrode assembly was implanted. A repetitive train of stimuli was used to elicit the phenomena. The presence of SD was shown by slow potential changes and diminution of direct cortical responses characteristic of SD in acute studies. A number of SD's could be produced on successive days, up to 2 weeks. These experiments show that exposure of the cortex is not a prerequisite for elicitation of the phenomena.
Paraventricular nuclei, neurohypophysis, and parturition
Authors: Nibbelink D. W.
Published: December 2017

A quantitative determination of oxytocic activity in the neurohypophysis and hypothalamus of the adult cat and dog was performed, using the rat uterus contraction method. Stereotaxically placed lesions in the paraventricular nuclei of the adult cat produced a marked depletion of oxytocic activity in the neurohypophysis. Experimental lesions in these nuclei in the pregnant cat resulted in marked dystocia at the end of the gestation period.
Some endocrine factors in regulation of fatty acid mobilization during fasting
Authors: Goodman H. M. , Knobil E.
Published: December 2017

In the rat, hypophysectomy, adrenalectomy, or thyroidectomy do not abolish the increase in lipid mobilization normally observed during fasting as evidenced by an increase in the concentration of free (nonesterified) fatty acids (FFA) in the plasma. The magnitude of this response, however, is reduced following the ablation of these glands. In adrenalectomized animals, cortisol administration returns the response to normal. These findings lead to the conclusion that increased secretion by the pituitary, thyroid, or adrenal glands does not initiate FFA mobilization during fasting, but that optimal function of these glands is requisite for the normal metabolic response to food deprivation.
Effect of endotoxin on kidney function and renal hemodynamics in the dog
Authors: Hinshaw Lerner B. , Spink Wesley W. , Vick James A. , Mallet Edmund , Finstad Joanne
Published: December 2017

The effect of endotoxin on kidney function and renal hemodynamics in the intact dog has not been reported. The present study is a logical extension of previous work completed in eviscerated dogs and its purpose was to study the effects of lethal and sublethal injections of endotoxin on the kidney of the intact dog. PAH and creatinine clearance procedures were carried out in adult anesthetized animals. Findings show that administration of lethal doses of endotoxin results in impaired renal function which may be attributed to the effects of systemic hypotension, renal vasoconstriction, and a possible action of endotoxin on renal tubular activity. However, with sublethal doses of endotoxin, in which the systemic arterial blood pressure does not fall to hypotensive levels, a temporary increase in renal plasma flow may be observed which appears to be due to an effect of endotoxin on the kidney or to extrarenal influences.
Relation of body weight to excretion of endogenous sterol in rat
Authors: Ivy A. C. , Janecek H. M. , Wojciech R.
Published: December 2017

Five groups of 10, 31, 49, 11 and 10 female rats, weighing on the average 110, 148, 195, 252, and 297 g, respectively, were fed a synthetic sterol free diet for 14 days, the feces being discarded for the first 7 and retained for the next 7 days. The total lipids of the feces were analyzed for unsaponifiable (UM) and digitonin-precipitable material (DM). At the end of the 14 days the length and weight of the small intestine and weight of the liver were determined when the total body weights were those indicated above. It was found that the weight and length of the intestine and weight of the liver regressed curvilinearly on the body weight, whereas the combined weight of the intestine and liver regressed linearly on the body weight. The daily endogenous excretion of sterol, calculated from the DM in the UM, regressed linearly on the body weight, on the combined weight of the liver and small intestine, and on the calories required for maintenance. The intraspecies relationships found in this study on the rat confirm those for the interspecies relationships when the data on the rat, chicken, dog, and man were analyzed and compared.
Effects of fasting and alloxan diabetes on albumin synthesis by perfused rat liver
Authors: Marsh Julian B.
Published: December 2017

The net synthesis of plasma albumin by the rat liver perfused with a red cell suspension has been studied by a quantitative immunochemical method. Albumin synthesis was decreased by an average of 29% after a 24-hr fast in normal rats. It was also decreased by 41% in alloxan diabetic rats.
Specificity of zinc pathway in the rabbit: zinc-cadmium exchange
Authors: Cotzias G. C. , Borg D. C. , Selleck B.
Published: December 2017

Marked perturbations of Zn65 clearance curves and subsequent blood and tissue radioactivity levels were produced in rabbits by the injection of either ZnSO4 or of CdSO4 carriers. The responses to challenge with cadmium loading, although not identical, were sufficiently similar to those obtained with zinc to suggest that cadmium may be an antimetabolite for zinc. In contrast, no deviations from control experiments were produced by injections of CuSO4, Ga(C2H3O2)2, or HgCl2. Hence, those segments of the physiological pathway of zinc through the body that were tested by these experiments proved to have sufficient specificity to discriminate completely against these latter elements.
Exchange diffusion and runout of Diodrast-I131 from renal tissue in vitro
Authors: Kinter William B. , Cline Allen L.
Published: December 2017

Runout of preaccumulated Diodrast-I131 from isolated goldfish kidneys was investigated with particular attention to metabolic inhibition, competition by related organic acids, and low temperature. Addition of metabolic inhibitors, such as cyanide, to medium bathing the tissue increased Diodrast runout, i.e., rate of net movement into medium. In conjunction with these same inhibitors, competitors either decreased or further increased runout, e.g., probenecid exhibited the former and p-aminohippurate (PAH) the latter action. In the absence of metabolic inhibition, increasing medium concentration of a given competitor first increased and then decreased runout. Low temperature decreased control runout as well as actions of competitors and metabolic inhibitors. Differences in lipid solubility correlate with differences in action of particular competitors. These results are interpreted as evidence for a complex membrane process mediating outward Diodrast movement, e.g., a carrier cycle which exhibits characteristics of both exchange and facilitated diffusion. Speculatively, such a process could be the basis for both active secretion and reabsorption, i.e., bidirectional tubular transport of organic acids.
Ion movements in isolated rabbit aortic strips
Authors: Briggs Arthur H. , Melvin Suzanne
Published: December 2017

Ca45, K42, and Na24 exchanges were compared with tension changes induced by epinephrine (1.5 x 10–5 m) and by lowering the extracellular sodium concentration (Na)0 in normal and glycerol-extracted isolated spiral strips of rabbit aortas. Contractions induced by epinephrine and lowering the (Na)0 to one-fifth of normal resulted in an increased Ca influx of 107 and 225%, respectively. Epinephrine had no effect on tension or Ca influx in glycerol-extracted preparations. Ca45 efflux was not affected. Epinephrine in normal Ringer's solution had no effect on Na24 net entry, but increased K efflux 486% and K influx 107% with the development of 1.467 g of tension. K efflux and influx increased 215 and 30%, respectively, when the aortas were placed in Ca-free Ringer's solution, whereas tension decreased 0.158 g. These data were interpreted to suggest that Ca, not Na or K, was directly involved in contraction in isolated rabbit aortic strips. Na appears to act through an antagonism with Ca.
Effect of temperature on reactive hyperemia in skeletal muscle
Authors: Yonce Lloyd R.
Published: December 2017

Circulatory reactivity to vascular occlusion for periods of 30, 60, and 120 sec was determined on eight isolated canine gracilis muscles under normothermic and hypothermic conditions (approx. 37.5 C, 25 C, 18 C, and 7 C). Control blood flow either increased or decreased when the temperature was lowered but was quite stable at each temperature step. The amount of reactive hyperemia always decreased with hypothermia and was statistically independent of effect from the control blood flow as the temperature was lowered. Recovery from reactive hyperemia required approximately the same time for the three periods of occlusion at each temperature step. The effect of hypothermia on control blood flow appears to determine the time required for recovery from reactive hyperemia.
Synthesis of canine seromucoid before and after total hepatectomy
Authors: Kukral John C. , Pancner Ronald J. , Louch June , Winzler Richard J.
Published: December 2017

The incorporation rate of S35 DL-methionine into the perchloric acid-soluble (seromucoid) fraction of serum was studied in the same four dogs before and after a one-stage total hepatectomy. This incorporation rate was used as an index of seromucoid synthesis. In all dogs before hepatectomy there was a rapid incorporation rate reaching a maximum synthesis in approximately 6 hr after injection. After hepatectomy the average incorporation rate was reduced to about one-third of prehepatectomy levels. It is concluded that in the dog most of the perchloric acid-soluble (seromucoid) fraction is of hepatic origin whereas a smaller part is synthesized by extrahepatic tissues.
Effect of chlorothiazide on electrolyte excretion in intact and adrenalectomized rats
Authors: Kahn Melvin
Published: December 2017

The acute effects of the oral administration of chlorothiazide on electrolyte and water excretion were studied in adrenalectomized and intact male Sprague-Dawley rats. After the administration of a sodium chloride and sodium bicarbonate load, urine for analysis was collected anaerobically for two consecutive 4-hr periods. Half of the intact and adrenalectomized animals received chlorothiazide, 200 mg/kg; the others served as controls. The diminished ability of adrenalectomized rats to excrete ammonia and sodium chloride was confirmed. In both the intact and adrenalectomized animals receiving chlorothiazide there was a significant and equivalent increase in urine pH, sodium, chloride, bicarbonate, total solute, and water excretion during the first 4 hr after administration of the drug when compared to the untreated controls. During the second 4 hr, there was no apparent response to chlorothiazide in either group. It is concluded that the diuretic effect of chlorothiazide is not a consequence of mineralocorticoid antagonism as has recently been proposed.
Hemorrhagic shock in the monkey
Authors: Einheber Albert , Cerilli G. James
Published: December 2017

African green monkeys were subjected to varying degrees and durations of hemorrhagic hypotension (arterial reservoir technique) and the shed blood returned. Seven monkeys bled to a mean arterial blood pressure of 50 mm Hg for 5.0 or 6.5 hr, 40 mm Hg for 5.5 hr, or 35 mm Hg for 4.5, 5.0, 5.5, or 6.0 hr survived. Of five monkeys bled to 35 mm Hg for 7.0 hr, three survived and two died. Two monkeys bled for 8 or 9 hr against 35 mm Hg died. Deaths occurred 6–24 hr postreinfusion. Maximum bleeding volumes (MBV) averaged 3.7% of body weight. During hypotension, self-transfusion volumes ranged from 1% to 34% of the MBV, rectal temperature declined 4.9 C, and plasma lactic dehydrogenase activity increased markedly. The intestinal pathology of the nonsurviving monkeys, which is minimal, contrasts sharply with that of dogs that die of hemorrhagic shock. These monkeys give evidence of a greater tolerance for hemorrhagic hypotension than the commonly studied mammalian nonprimate, but they too become unresponsive to transfusion if hypotension is sufficiently severe and prolonged.
Effect of pure oxygen at reduced pressures on metabolic changes in mice
Authors: Berry L. Joe , Smythe Dorothy S.
Published: December 2017

The gravimetric "equivalence" between protein catabolized and carbohydrate synthesized in response to cortisone was determined in mice exposed for periods of 3 weeks to air at simulated 14,000-ft or 20,000-ft altitude or to pure oxygen at simulated 30,000-ft or 34,000-ft altitude. For control mice and those exposed to pure oxygen at 30,000 ft and 34,000 ft the equivalence was, respectively, 92%, 90%, and 98%. Animals on air at 14,000 ft and at 20,000 ft had, respectively, 46% and 37% equivalence. In all mice, protein catabolism was the same, statistically, but carbohydrate synthesis varied. Mice exposed to air at 14,000 ft or 20,000 ft show 35% and 46% survival after a dose of endotoxin survived by 84% of control animals and 86% of those kept for 3 weeks on pure oxygen at simulated 34,000 ft. Other effects of low barometric pressure are described.
Osmotic phenomena in smooth muscle
Authors: Bozler Emil
Published: December 2017

Anomalous osmotic phenomena observed in the frog's stomach muscle bathed in certain solutions were analyzed. It is suggested that intracellular hydrostatic pressure is an important factor in the exchange of water in these situations. In very dilute solutions of CaCl2 and MgCl2 (2–8 mm) the muscle maintains a large difference in the concentration of solutes between the fibers and its medium; it swells only moderately, remains semipermeable, can contract, and becomes rigid. Osmotic balance probably is determined largely by hydrostatic pressure arising from elastic tension in internal structures, as it is in a strongly cross-linked gel. Swelling in isosmotic KCl solution is slow; the addition of 2 mm CaCl2 causes shrinking. Uptake of water in these solutions probably is opposed by internal hydrostatic pressure produced by a sustained contracture. The force produced under various conditions correlates well with the volume changes. Shrinking in isosmotic sugar solutions to which 2 mm CaCl2 or MgCl2 is added probably has the same cause. The role of the cell membrane under conditions of increased hydrostatic pressure within the fibers is discussed.
Role of the liver in calorigenic action of epinephrine and norepinephrine
Authors: Skarin Arthur T. , Lockwood Marilyn A. , Griffith Fred R.
Published: December 2017

Intravenous infusion of epinephrine and norepinephrine into eviscerated cats at rates of 4 µg/kg/min for 5 min results in an increase in oxygen consumption to an average 121% and 123% of control, respectively, with return to control level in the 15-min period after infusion. A similar response is obtained in normal cats during epinephrine infusion, but only in this group is a secondary or delayed rise to an average 110% of control noted in the 15-min period after infusion. It is suggested that the calorigenic action of epinephrine might be separated into an immediate effect occurring during intravenous infusion, independent of the presence of the liver, and a delayed or secondary effect occurring after infusion, requiring the presence of the liver. Both drugs change lung volume and thus introduce artifacts that interfere with measurement of oxygen consumption by conventional methods. This is overcome by use of a thermostat-controlled compensating body chamber which frees the oxygen consumption record from any dependence on lung volume.
Excretion of nitrogen compounds by perfused frog liver
Authors: Antonijevič M. , Lebez D.
Published: December 2017

The differences in excretion of nitrogen compounds in the perfused livers of summer and winter frogs ( Rana esculenta) are related to temperature change of environment. From the results obtained it was established that in summer (over 15 C) the nitrogen metabolism was about five times more intensive than in winter (below 10 C).
Effects of norepinephrine on blood glucose and free fatty acids in cold-adapted rats
Authors: Rimmer Anne Davenport , Schönbaum E. , Sellers E. A.
Published: December 2017

Norepinephrine (0.5 mg) was given intraperitoneally to albino rats adapted to room temperature (23 C) and to cold (2 C). The rats were killed at selected time intervals thereafter, and the blood levels of free fatty acids (FFA) and glucose were estimated. Both groups showed an initial steep rise in blood FFA and a slight rise in blood glucose. After 1 hr the FFA levels were at their maximum in the 2 C rats but had fallen to nearly base-line levels in 23 C rats. Blood glucose levels remained slightly elevated for the whole 1-hr period in the 2 C rats, but in the 23 C rats a secondary greater rise took place toward the end of the period. Different metabolic responses follow the administration of a single dose of norepinephrine to 2 C and 23 C rats.
Permeability of lymphatic vessels
Authors: Mayerson H. S. , Patterson R. M. , McKee A. , LeBrie S. J. , Mayerson P.
Published: December 2017

Substances of various molecular sizes were infused through leg or mesenteric lymphatics of anesthetized dogs and their concentrations were followed in thoracic duct lymph and plasma for the subsequent 2 1/2 hr. An isolated in vivo popliteal lymph node preparation was also perfused with some of the same substances. Small molecules were found to diffuse rapidly into the blood stream but hindrance to free exchange between lymph and plasma becomes progressively greater as molecular size increases. Somewhere between molecular weights of 600 and 2,300 it increases significantly so that, at or above the latter level, larger molecules are retained in approximately the same amount, irrespective of molecular size. No evidence of trapping by the popliteal node was seen with the largest substance used, dextran, of average molecular weight of 412,000. Urea in high concentrations exerted a "toxic effect" on the lymphatic vessels and node, rendering them more permeable to albumin. Sodium thiocyanate also exerted a similar action.
Effect in dogs of various portal vein shunts on response to insulin
Authors: Starzl Thomas E. , Butz George W. , Meyer William H. , Torok Elizabeth E. , Dolkart Ralph E.
Published: December 2017

Surgical alterations of portal drainage patterns were made in dogs in order to determine the effect of redistribution of endogenous and injected insulin. With an Eck fistula, progressive diminution of hypoglycemic response to insulin was noted. With a reverse Eck fistula, the fall in venous blood sugar was comparable whether injection was given via the portal system or systemically. With portacaval transposition, in which the pancreatic drainage is diverted from the liver, no alterations in general health, fasting blood sugars, or insulin response were noted. The results are discussed in relation to recent concepts in which insulin is thought to regulate or be regulated by the liver.
Lipolytic activity in rat heart
Authors: Björntorp Per , Furman Robert H.
Published: December 2017

In homogenates of rat heart pronounced lipolytic activity was found which had a broad pH optimum between 7.5 and 8.5. In the presence of a high concentration of NaCl or protamine sulfate an activity peak persisted between pH 6.5 and 7. This activity was greatest when hearts from fasting animals were preincubated with epinephrine and subsequently assayed in the presence of albumin. The activity was least in heparin-incubated samples and was inhibited by NaF. When lipase activity was determined in the presence of NaF a pH optimum of 8.5 was found. This lipase required serum protein and ammonium sulfate for optimal activity and could be inhibited by high concentrations of NaCl and by protamine sulfate. The yield of this lipase was similar whether hearts were obtained from fasting or from fed rats. This lipase was considered identical with the lipoprotein lipase described by E. D. Korn. It was found only in small amounts in the medium after incubation, in the presence of heparin, of the whole heart but in greater amounts when minced or sliced heart was used. After differential centrifugation most of the activity of both lipases was found in the mitochondrial fraction and in the soluble fraction.
Neural limitations of visual excitability. IV: spatial determinants of retrochiasmal interaction
Authors: Battersby William S. , Wagman Irving H.
Published: December 2017

Visual excitability changes were obtained from two trained observers by measuring threshold with a test flash of light at varying temporal intervals from a supraliminal conditioning flash. In monocular observation the two flashes were presented to the same eye; in binocular observation the conditioning flash was exposed to one eye and the test to the homonymous location in the other eye. The conditioning target size was varied while the concentrically placed test flash was held constant. In all instances, threshold rose when test preceded conditioning flash in time, reaching a maximum at about a o-msec interval. As test flash was progressively delayed with respect to conditioning flash onset, thresholds fell to an asymptote, returning to resting level only after termination of the conditioning flash. Both monocularly and binocularly, an increase in the magnitude of threshold rise was produced by making the conditioning target smaller, the greatest proportionate effect being obtained binocularly. These findings indicate that central (retrochiasmal) processes are critical with respect to spatial interaction in the visual system, a conclusion compatible with recent studies on the cortical receptor field.
Peripheral neural paths mediating avoidance of radiation in rats
Authors: Barnes Charles D.
Published: December 2017

The number of seconds per minute that male rats electively spent in a chamber X-irradiated at 32 r/min was measured in four groups: normal animals, animals which had received an intraperitoneal injection of 1 ml of 0.5% procaine, animals which had undergone bilateral splanchnicotomy, and sham-operated animals which had undergone all procedures preparatory to splanchnicotomy and which received 1 ml of distilled water intraperitoneally just before a test. Normal and sham-operated animals exhibited avoidance of radiation within 5 min of exposure, whereas splanchnicotomized or procainized rats showed no avoidance during the first 20 min of a 40-min test. It is suggested that an early component of radiation avoidance is mediated by splanchnic impulses elicited by the breakdown of the mucosa of the duodenum, small intestine, and, possibly, the stomach; and that breakdown of more resistant portions of the gastrointestinal mucosa (in the mouth, esophagus, and rectum) contributes to a late component.
Pulmonary vascular response to acute hypoxia in normal, unanesthetized calves
Authors: Kuida Hiroshi , Brown Arthur M. , Thorne Joseph L. , Lange Ramon L. , Hecht Hans H.
Published: December 2017

The natural occurrence of altitude-dependent pulmonary hypertensive heart disease in cattle stimulated an investigation of the effect of experimentally induced acute hypoxia on the pulmonary vascular resistance of normal unanesthetized calves. Gas mixtures of 10–16% O2 in N2 were administered through an endotracheal tube, for periods averaging 7 min, 22 times during 19 studies in 15 animals. Cardiac catheterization and dye dilution techniques were used to measure arterial and mixed venous blood gas composition (Saoo2, Svoo2), pulmonary (PAP) and carotid arterial (CAP) pressures, and cardiac output (CI) before, during, and occasionally after hypoxia. Pulmonary artery wedge pressure was measured in some animals and did not change. Changes in calculated pulmonary vascular resistance (PVRI) were assessed to infer alterations in vascular tone. Mean changes ±se of various parameters were as follows: Saoo2, –30 ± 4%; CI, +1.57 ± 0.5 liters/min/m2; PAP, +12.7 ± 2 mm Hg; PVRI, +0.7 ± 0.3 mm Hg/liter/min/m2. All were statistically significant at the 5% level. The relative increment in PAP was three times greater than in CI. It is concluded that hypoxia produces pulmonary vasoconstriction in these animals. The magnitude of the response is greater than has been observed in previous studies on intact unanesthetized animals of other species.
Effect of temperature on erythropoiesis and red cell survival in the frog
Authors: Cline M. J. , Waldmann T. A.
Published: December 2017

The effect of environmental temperature on erythropoiesis and erythrocyte life span was studied in frogs maintained at 4 C or 24–26 C. The red cell incorporation of radioiron was used as an index of the rate of erythropoiesis and diisopropylfluorophosphate-P32 was used to measure red cell survival. The red cell life span in frogs kept at 24–26 C was approximately 200 days. The incorporation of Fe59 into circulating red cells during the first 10 days after isotope administration was significantly greater in frogs at 24–26 C than in frogs at 4 C. The peripheral hematocrit decreased in groups of frogs kept at 4 C during the period of observation. The inconstancy of the hematocrit and presumably of the total red cell volume did not permit any definite conclusions regarding the apparently longer erythrocyte life span at low environmental temperatures.
Cardiovascular receptors and blood titer of antidiuretic hormone
Authors: Share Leonard , Levy Matthew N.
Published: December 2017

Bilateral cervical vagotomy resulted in a threefold increase in the blood titer of antidiuretic hormone (ADH) in the dog. Occlusion of both common carotid arteries in dogs with vagi intact was without effect. However, after vagotomy, occlusion of the common carotid arteries resulted in an additional 2.5-fold increase in the blood level of ADH. This response was blocked by denervation of the carotid sinuses 1–2 weeks prior to the experiment. Baroceptors located at the junction of the thyroid and common carotid arteries do not appear to be of great importance in this response, since occlusion above the thyrocarotid junction was as effective as occlusion below this junction. It is concluded that there are at least two groups of receptors concerned with the regulation of the blood level of ADH within the vascular system: one group located in the carotid sinuses, and a second group with afferent nerve fibers in the vagi.
Cardiovascular actions of venom of the stonefish Synanceja horrida
Authors: Saunders Paul R. , Rothman Sol , Medrano Victor A. , Chin H. P.
Published: December 2017

Possible mechanisms of the hypotensive effect of small-to-moderate doses of stonefish venom in rabbits were investigated. Some decrease in blood pressure occurred in the absence of, or prior to, a decrease in force of contraction of the heart, suggesting that peripheral vasodilatation was at least in part responsible for the blood pressure fall after small doses of venom. A decreased force of contraction was associated with the greater decline in blood pressure produced by larger doses of venom. Vasodilatation did not occur in skeletal muscle after intra-arterial injection of venom, and possible effects on other vascular beds were not investigated. Adrenergic blockade was excluded as a mechanism of action of the venom, and evidence of a lack of effect on autonomic ganglionic transmission was obtained. The pressor responses to carotid artery occlusion and anoxia and the depressor responses to central stimulation of the cut right vagus and depressor nerves were unaffected by hypotensive doses of venom.
Toxic effects of ouabain on Purkinje fibers and ventricular muscle fibers
Authors: Vassalle Mario , Karis Johannes , Hoffman Brian F.
Published: December 2017

Toxic effects of ouabain on single Purkinje fibers and ventricular muscle fibers were investigated in vitro by microelectrode technique. Toxicity developed much earlier in the specialized conducting fibers and consisted of a progressively increasing rate of diastolic depolarization and a decrease of amplitude and duration of the action potential. The majority of Purkinje fiber preparations developed extrasystoles and rapid spontaneous rhythms. The resting potential was much decreased. The ouabain-induced changes in ventricular muscle fibers occurred much later than did changes in Purkinje fibers and consisted of a decrease in the plateau and in the amplitude of the action and resting potential. Spontaneous depolarization was not observed in muscle fibers. The effect of the rate of stimulation on the development of ouabain toxicity was studied in another series of experiments on driven and quiescent muscles. Signs of toxicity appeared earlier in the driven muscles than in duplicate quiescent muscles and, at faster rates of stimulation, the time required for the toxic changes was shortened.
Myocardial removal of free fatty acids under normal and pathological conditions
Authors: Scott John C. , Finkelstein L. J. , Spitzer John J.
Published: December 2017

Myocardial arteriovenous difference in free fatty acids (FFA) and coronary flow was determined in dogs under morphine-chloralose anesthesia. Fifteen minutes after the administration of insulin the A-V difference decreased. FFA uptake did not change significantly. Alloxan diabetes decreased the utilization per cent of FFA. Norepinephrine elevated myocardial uptake and arterial FFA. Hypoxia did not change FFA uptake. Hypothyroidism lowered myocardial uptake. Left ventricular O2 consumption increased after administration of atropine in both normal and hypothyroid animals, whereas hypothyroidism was associated with a decreased value. A significant correlation was found in normal dogs between arterial FFA concentration and myocardial uptake. A different relationship suggested itself in hypothyroid animals. A correlation was also shown between the per cent of myocardial O2 consumption calculated for complete oxidation of FFA and the myocardial R.Q.
Electrolyte and water transport by salivary gland slices
Authors: Schneyer L. H. , Schneyer C. A.
Published: December 2017

Net movements of water, electrolytes, and total solids were investigated in slices of rat submaxillary gland to delineate transport mechanisms of possible significance in normal salivary secretion. Gland slices gained weight in oxygenated Krebs-Ringer-phosphate from greater influx of water than efflux of solids. Most of the water gained entered cells. Tissue and cell K decreased, while Na and Cl increased. In KRP-N2, slices gained even more weight than in O2, from increased water influx; here more of the water remained in extracellular space. Gain of tissue Cl was comparable but Na gain and K loss by tissue and cells were greater than in oxygenated medium. Readmission of O2 after N2 incubation resulted in weight loss from further loss of solids with no change in total tissue water; however, a redistribution of water in the tissue, involving expansion of intracellular at the expense of extracellular space, was observed. Tissue and cell Cl further increased; K was reaccumulated, and Na left the cells. Net Na efflux and K influx against chemical and electrical gradients occurred consistently. Submaxillary gland cells can extrude Na and accumulate K by active transport.
Coagulation studies on the electrophoretic fractions of AFIF
Authors: Triantaphyllopoulos E. , Triantaphyllopoulos D. C.
Published: December 2017

Anticoagulant fraction of incubated fibrinogen (AFIF), obtained from human fibrinogen by simple incubation or from bovine fibrinogen (prepared by the method of Laki) after addition of streptokinase-activated human fibrinolysin and incubation for several days, was subjected to continuous flow paper electrophoresis in 0.02 m, pH 8.6 Veronal buffer, at 800 v and about 40 ma. Both kinds of AFIF separated into two components: a major one having the same electrophoretic mobility as the intact fibrinogen and a second more electronegative amounting up to 21% of the first. The latter migrated with a mobility intermediate between that of albumin and α-globulins or between the mobilities of α-and ß-globulin fractions of human plasma, depending on the origin of the preparation human or bovine, respectively. Further studies showed that if the incubation of human fibrinogen was interrupted before the sample became completely unclottable by thrombin, the AFIF obtained showed only the first component on electrophoresis. Both fractions of human AFIF were found able to inhibit the clotting of bovine fibrinogen by thrombin to the same extent as the original sample, however, only the second component inhibited the rate of formation of plasma thromboplastin when added to a thromboplastin generating system.
Renal excretion of magnesium in the rabbit
Authors: Raynaud C.
Published: December 2017

In rabbits, after rapid intravenous injection of Mg28, the plasma and urinary specific activities, corrected for transit time, are at all times in equilibrium. Injection of Mg28 during stop flow does not reveal any tubular zone permeable to magnesium. On the other hand, the magnesium behavior is in many ways comparable to that of a glomerular substance. These three arguments lead to the view that urinary magnesium is of essentially glomerular origin, and rule out any mechanism of tubular exchange or secretion.
Micropuncture study of renal excretion of water, K, Na, and Cl in the rat
Authors: Litchfield Judith B. , Bott Phyllis A.
Published: December 2017

Inulin, K, Na, and Cl were determined on identical samples of proximal tubule fluid, urine, and serum in nondiuretic rats. Tubule fluid-serum ratios for inulin showed that at least two-thirds of the filtered water was reabsorbed proximally. Potassium ratios remained at 1, suggesting incomplete reabsorption. Early proximal sodium and chloride ratios were close to 1, but more distal regions had ratios of approximately 1.1 and 1.4, respectively. pH measurements on tubule fluid of nondiuretic and diuretic rats demonstrated proximal acidification with values as low as 6.7. Under conditions of extreme mannitol diuresis further acidification was negligible, whereas in nondiuretic rats urine pH was below 6.
Biological actions of free and albumin-bound arachidonic acid
Authors: Ichikawa Shigetaka , Yamada Jiro
Published: December 2017

Smooth-muscle-stimulating and hypotensive actions of free and albumin-bound arachidonic acid were investigated. The jejunum and ileum of both guinea pigs and rabbits were most sensitive to the acid among the isolated small intestines of these two species and rats, and exhibited a submaximal contraction at the concentration of 1.5 x 10–7 g/ml in Tyrode's solution at 37.5 C. A dose of 3–6 µm of the acid produced a fall (40–80 mm Hg) in the rabbit's blood pressure. The dogs were quite refractory to the depressor action of the acid. Albumin-bound arachidonic acid exhibited the same activity as the free acid in regard to both smooth-muscle stimulation and hypotensive action. These results indicate that arachidonic acid could display its biological actions when the acid is released into the blood stream.
Abolition of ventilatory response to inhaled CO2 by neurological lesions
Authors: Masland William S. , Yamamoto William S.
Published: December 2017

Evidence is presented for the localization of central chemoreceptors. Respiratory minute volume was measured in rats after surgical procedures that removed known or presumed chemoreceptor areas in various combinations. In each case the control ventilation was measured during inhalation of 100% O2, and the test response was the steady state ventilation on breathing O2 with either 5% or 10% CO2 added. To test completeness of carotid chemoreceptor denervation, 6–8% O2 in N2 was employed. Our data show that ventilatory response to inhaled CO2 is abolished if three lesions are produced simultaneously. The lesions must destroy the carotid chemoreceptor, a region surrounding and including the area postrema in the medulla, and diencephalic tissue rostral to a line passing through the posterior commissure dorsally and just behind the optic chiasm ventrally. If any of the three remains intact the ventilatory response is indistinguishable from that of the anesthetized, unoperated control animal. Minute volume is not abnormally low in the CO2-insensitive animal, and superficially the respiratory pattern is of normal rate and depth. A speculative hypothesis regarding the mechanism of function of the non-neural tissue of the area postrema is proposed.
Calcium movements during potassium contracture in isolated rabbit aortic strips
Authors: Briggs Arthur H.
Published: December 2017

Ca movements and tissue Ca concentrations were determined during K2SO4-induced contractures in isolated rabbit aortic strips. The initiation and maintenance of the contractures were both dependent on the presence of Ca and associated with an increase Ca influx. There was a 2.8-fold increase in Ca influx in the initial period and a 1.9-fold increase during the sustained phase of the contracture as compared to controls in Ringer's solution. Furthermore, Ca influx during K2SO4 contracture was dependent on the extracellular Ca concentration up to approximately 0.3 mm and there was a linear relationship between the tension developed and the rate of entry of Ca. There was no significant difference in the tissue Ca concentration after K2SO4 contractures as compared to controls in Ringer's solution. The data were interpreted to suggest that contracture was initiated by an influx or release of Ca into the vicinity of the contractile elements of the aorta and that the maintenance of the contracture was dependent on a sustained level of ionized Ca in this region.
Formation of a reticuloendothelial-depressing substance in the ischemic intestine
Authors: Blattberg Benjamin , Levy Matthew N.
Published: December 2017

The phagocytic index of the reticuloendothelial system of normotensive assay dogs was determined by measuring the clearance of carbon particles from the blood. These animals were cross-transfused with portal venous blood from experimental dogs bled to a mean arterial pressure of 40 mm Hg for 90 min. The superior mesenteric artery of the experimental animal was perfused at a normal rate of 8.8 ml/kg/min in half of the experiments and at a rate of 3.2 ml/kg/min (equivalent to rates prevailing in hemorrhagic hypotension) in the remaining experiments. Statistical comparison showed a significantly greater ( P < 0.01) depression of reticuloendothelial activity in the group with lower flows. The results strongly suggest that a humoral reticuloendothelial-depressing substance is formed in the ischemic intestine of dogs subjected to hemorrhagic hypotension.