bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Iodoacetic Acid on Oxygen Consumption and Survival of Newborn Mice
Authors: Fitzgerald Laurence R.
Published: December 2017

When newborn mice are given injections of iodoacetic acid (IAA), it is found that doses of 10 mg/kg have little effect upon oxygen consumption. Doses of 60 mg/kg block all oxygen uptake within 1 hour. The animals given 10 mg/kg will survive, in air, for nearly 24 hours, while those given 60 mg/kg all die within 1 hour. If exposed to nitrogen after the injection, animals given 10 mg/kg survive as well as uninjected mice, while those given 50–60 mg/kg show the rapid death (within 3 min.) that has been reported by others. Calculations, based on probable oxygen content of the blood and other tissues of the newborn mouse, and on the minimum rate of oxygen utilization which will permit survival, show that the oxygen stores within the animal are sufficient to maintain the minimal rate of metabolism for extended periods in the absence of an external source of oxygen. Failure of the mice to survive exposure to nitrogen after IAA injection appears to depend on blocking the use of these oxygen stores as well as blocking glycolysis.
Effect of Ammonium Intoxication on Metabolism of ß Hydroxybutyrate
Authors: Neptune Edgar M.
Published: December 2017

During a constant infusion of sodium d,l ß hydroxybutyrate there is a fall in blood glucose. There is, however, a marked rise in blood glucose when ammonium carbonate is injected during the infusion of ß hydroxybutyrate. Except for a decrease in hepatic vein ß hydroxybutyrate and a rise in hepatic vein acetoacetate, there is no marked disturbance of peripheral ketone metabolism. These observations suggest that glucose participates in ketone metabolism at the level of the citric acid cycle.
Response of Single Medial Geniculate Units to Repetitive Click Stimuli
Authors: Vernier Vernon G. , Galambos Robert
Published: December 2017

The capacity of single units isolated in the medial geniculate of unanesthetized, paralyzed cats to respond to clicks delivered to the ear at rates between 1 and 200/sec. is described. Most units respond one-to-one at low click rates. When the interval between stimuli is shortened some stimuli fail to evoke response, and when it is made very brief the unit may respond only to the first click in the train. The click frequency at which a unit responds to 50% of the stimuli is reasonably stable, but can be modified by the administration of morphine.
Steroidal Aspects of Pregnane Inhibition of Progesterone in Decidual Development
Authors: Velardo Joseph T.
Published: December 2017

Previously, Hisaw, Velardo and Ziel (1954) reported that several of the pregnanediols inhibited decidual development in progesterone-treated, ovariectomized pseudopregnant rats. The present report is an attempt to ascertain the modus operandi of this decidual inhibition. Utilizing three experimental designs, it has been ascertained that both pregnane 3 α, 20 ß diol, and pregnane 3 ß, 20 ß diol modify the response of the traumatized uterus of the ovariectomized rat to progesterone; consequently, a reduction in decidual tissue results. These experiments further show that the initial estradiol-17 ß action is not opposed, nor is the growth response of the uterus of the ovariectomized rat interfered with by the concurrent administration of estradiol-17 ß and either one of the two pregnane compounds under investigation. These data indicate that 1) the inhibition of decidual tissue is the result of the action of these pregnanes on progesterone activity, and 2) these compounds do not alter the response of the uterus and the vagina of the ovariectomized rat to estradiol-17 ß
Reflectance Spectra and Some Respiratory Reactions of Bovine, Equine and Human Thrombocytes
Authors: Goucher Charles R. , Kocholaty W.
Published: December 2017

Reflectance spectra of human, bovine and equine thrombocytes reveal the existence of pigments which absorb in the visible region of the spectrum. The chromatic properties of these pigments change with the redox potential of the cell. These spectra alterations suggest the existence of a cytochrome system, but the position of the absorption bands does not permit their identification with known mammalian cytochromes. However, platelet homogenates contain a cytochrome oxidase which oxidizes mammalian cytochrome c and which is inhibited by sodium azide. Platelet extracts also contain a DPNH oxidase system which is inhibited by sodium azide.
Effect of Electrolyte Disturbances in the Pregnant Rabbit on the Fetus
Authors: Dancis Joseph , Worth Melvin , Schneidau Peter B.
Published: December 2017

The possibility that the placenta may protect the fetus against electrolyte disturbances in the mother was investigated in rabbits. Hyperosmolarity of the blood of the doe was induced with intravenous infusions of hypertonic sucrose. The osmotic pressure of the fetal blood approximated that of the mother within an hour and possibly considerably sooner. Acidosis was induced with ammonium chloride. The maternal plasma chlorides were in creased for roughly 3 hours before the fetal chlorides showed similar increases. However, after prolonged acidosis the fetal electrolyte changes paralleled the maternal with a lowered ph and CO2 content and elevated plasma chlorides.
Recovery of Blood Neutrophils After Acute Peripheral Depletion
Authors: Patt Harvey M. , Maloney Mary A. , Jackson Eugenia M.
Published: December 2017

Blood neutrophil recovery in the dog appears to be qualitatively similar whether leucopenia is achieved by injection of leucocyte antiserum to remove the cells in vivo or by exchange transfusion with leucocyte-depleted blood. Return to the control level after antiserum injection occurs within 3–5 hours with neutropenias in excess of about 50% and is followed by neutrophilia of variable degree with restoration of the normal count usually by 24 hours. There is reason to think that recovery is accomplished in large part by an accelerated release of cells from marrow. This conclusion, which is based mainly upon the appearance of numerous band cells in the periphery, is supported by the results obtained in x-irradiated animals and is consistent with related observations by others and with theoretical considerations of neutrophil balance. The extent of release of nonsegmented cells is related more to the relative (percentage) change than to the absolute decrease in neutrophils. These observations can be interpreted to mean that the number of mature cells available for release from the marrow reservoir is a function of the normal steady state level in blood. Possible mechanisms of compensation for the decline in cells in the periphery are discussed and exploratory studies are reported. It is suggested that the control system may include a suppressor feedback between mature neutrophils and blood-forming sites.
Effect of Splenectomy, Nephrectomy and Other Procedures on Epinephrine-Induced Pulmonary Edema
Authors: Polli John F. , Luisada Aldo A.
Published: December 2017

The effect of various operative procedures and tissue extracts on epinephrine-induced pulmonary edema (EPE) was studied in 338 rabbits. Anesthesia and laparotomy with manipulation of the viscera had a definite protective effect against EPE. Similar effects were obtained with the intraperitoneal injection of a foreign substance or pretreatment with ACTH or adrenal cortex steroids. This protection is believed to be the result of adrenal cortical activation by stress. Splenectomy had a protective effect against EPE which was greater than that of sham operations. The injection of splenic extract in splenectomized animals decreased survival time and increased the severity of the edema, whereas injection of hepatic extract had a less marked effect. Both unilateral and bilateral nephrectomy had a protective effect against EPE.
Alteration of Contractile Response of Artery Strips by a Potassium-Free Solution, Cardiac Glycosides and Changes in Stimulation Frequency
Authors: Leonard Edward
Published: December 2017

Electrical stimulation of helically cut strips of rabbit carotid artery, mounted so as to allow development of tension isometrically, causes a contraction-relaxation cycle which remains reproducible for many hours, after an initial period of rising contractile response. If the strip is equilibrated in a potassium-free Krebs solution, or if a cardiac glycoside is added, the tension developed on electrical stimulation increases, the time required for relaxation is prolonged and contracture may also be observed. Desoxycorticosterone or progesterone decrease the contractile response of the strip. The arterial smooth muscle strip also exhibits the staircase phenomenon, a stepwise increase in tension on repeated stimulation after a period of rest. It is suggested that the changes in contractile response induced by a potassium-free medium, addition of glycosides, or repetitive stimulation are related to a loss of muscle fiber potassium. The action of the glycosides on the artery strip is discussed from the viewpoint of a model mechanism for altering vascular smooth muscle activity by affecting intracellular electrolytes.
Response of Single Nerve Fibers at Different Hydrostatic Pressures
Authors: Spyropoulos Constantine S.
Published: December 2017

The effects of high hydrostatic pressure upon isolated single nerve fibers were investigated. Single nerve fibers were isolated from the nerve innervating the sartorius or semitendinosus muscle of the toad ( Bufo marinus). The responses of single nerve fibers were recorded using the ‘bridge-insulator,’ the ‘interface’ and the ‘three-compartment’ methods. Hydrostatic pressures up to 16,000 psi were developed with a hand operated hydraulic pump. The most striking effect of high pressures was the prolongation of the duration of the response. At 10,000 psi the duration was 4.5–5.0 times the duration at atmospheric pressures. The duration of prolonged responses (by previous tetanization) was not appreciably altered by high pressures. The amplitude, rheobase and shock-response interval were only slightly affected. At 5000 psi the shock-response interval increased by 5–15% and the rheobase by 10–15%.
Food Drive and Satiety in Yellow Mice
Authors: Hollifield Guy , Parson William
Published: December 2017

Spontaneous running activity during ad libitum feeding, fasting and refeeding was studied in inbred yellow mice. These studies suggest that the yellow gene per se is not associated with reduced activity and that inbred yellow mice have intact hypothalamic feeding centers. The relationship of these findings to obesity in yellow mice is discussed.
Mechanism of the Protective Action of Magnesium in Mechanical Trauma Involving Epinephrine and Norepinephrine
Authors: Gray Irving , Jordan William J. , Goldberg Nelson D. , Cash William D.
Published: December 2017

Pretreatment of animals subjected to tumbling trauma with MgSO4·7H2O injected intraperitoneally brings about a significant decrease in the mortality and a concomitant decrease in the concentration of the circulating epinephrine and norepinephrine. The pretreatment also prevents as large a decrease in blood volume as is seen in the untreated animals. In the treated animals, the small decrease that is seen soon returns to normal. It is proposed that the protective action of the Mg++ lies in its ability to maintain the blood volume and thereby prevent the increase in circulating catechol amines seen in the untreated animals.
Measurement of Regional Sodium Turnover Rates and Their Application to the Estimation of Regional Blood Flow
Authors: Dobson Ernest L. , Warner George F.
Published: December 2017

It has been possible to estimate the regional blood flow through quantitative analysis of the sodium wash out curve obtained by a method which involves the injection of sodium 24 into an artery and the subsequent monitoring of the region (limb) supplied by this artery with external counters. The normal resting sodium turnover rate in the human forearm was found to be 10%/min. corresponding to a blood perfusion factor of 0.040 liters of blood per liter of tissue per minute. In addition to these quantitative values this method has given qualitative information on the pattern of the vascular bed. Analysis of the manner in which the removal rate changes with time has indicated that there are regions of widely differing vascularities in the area seen by the counter. Measurements following epinephrine administration have demonstrated not only a quantitative change in flow but a qualitative one as well. The subcutaneous administration of 1 mg epinephrine caused a doubling of the average total sodium turnover rate indicating a twofold increase in blood flow. The observed changes in the shape of the clearance curves could not be explained by a simple increase in linear flow rate and therefore must have involved some change in the character of the vascular bed, i.e. the conversion of some regions of low vascularity to regions of high vascularity.
Interaction of Estrogens on the Vaginal Smear of Spayed Rats
Authors: Edgren Richard A. , Calhoun David W.
Published: December 2017

Employing the vaginal smear as an index of effect, combinations of various estrogenic substances were tested for interaction. Studies were concentrated at the approximate 50% response level. In a single experiment ED50 doses of the two estrogens in pure form were administered to two groups of spayed rats and a third group was injected with a mixture of one-half of each ed50; in one experiment three intermediate doses were employed. In all of the studies a given proportion of the ED50 of one compound was replaced by the same proportion of the ED50 of the other without mensurable change in biological response. These data are interpreted as indicating simple additive relationships among the compounds tested. Pairs studied were: estradiol-17ß with estriol; and estrone in combination with estradiol-17ß, estriol, methallenestril (Vallestril) and stilbestrol. The additive relationships described here are of particular interest in view of literature reports that indicate an interference between certain pairs of these compounds when uterine growth rather than vaginal cornification was used as an index of activity. This target organ differentiation suggests that various end points of estrogenic action differ in their responses to varying hormonal balances.
Biliary Excretion and Metabolism of Radioactive L-Triiodothyronine
Authors: Flock Eunice V. , Bollman Jesse L. , Grindlay John H.
Published: December 2017

Dogs with biliary fistulas metabolized triiodothyronine rapidly to inorganic iodide, as did normal dogs. The amount and distribution of I131 compounds in the urine were not greatly altered by withdrawal of the bile, which contained about one-fourth of the I131 administered. Dogs with biliary obstruction excreted more of compounds b, iodide and the conjugate than normal dogs. The absence of enterohepatic circulation of metabolic products of triiodothyronine usually excreted in the bile did not appreciably alter the products or rate of metabolism of triiodothyronine. Some of the same products of triiodothyronine appeared in both bile and urine but there was very little inorganic iodide in the bile and much more of the glucuronide and the water-soluble, column residual fraction.
CO2 Output and Energy Balance of Hereditary Obese Mice
Authors: McClintock Ruth , Lifson Nathan
Published: December 2017

The total CO2 outputs of young adult hereditary obese-hyperglycemic mice were measured over 2-day periods by means of the D2O18 method, and were found to be significantly higher than those of litter-mate controls. Since it had previously been postulated that the development of obesity in these animals was related in large part to a decreased total energy output, the energy balance of growing obese and normal mice was then studied. Food consumption, weight gains, and total CO2 outputs were determined at the ages of 6, 9 and 12 weeks. The CO2 outputs, which reflect the energy outputs, were of approximately the same magnitude for the two groups at 6 and 9 weeks of age, but were greater for the obese at 12 weeks. Food consumption remained nearly constant for both groups. An energy balance from these data is contrasted with one previously postulated by another group for similar mice.
Effect of Dose Rate on Iron Incorporation Into Newly Formed Erythrocytes of Rats Exposed to Gamma Radiation
Authors: Baum Siegmund J. , Kimeldorf Donald J.
Published: December 2017

Rats were subjected to 240 r gamma radiation at several dose rates (10 r/hr., 30 r/hr., 60 r/hr. and 120 r/hr.). At various days postradiation the animals were injected with radioactive iron and the appearance of the isotope in newly formed erythrocytes was measured in the circulation until it reached a maximum. Lowest Fe59 uptake was noted in animals injected with the isotope 24 hours postradiation. It was observed that dose rate influenced inversely the extent of iron incorporation during the recovery phase.
Water Metabolism of the Domestic Fowl From Hatching to Maturity
Authors: Medway W. , Kare M. R.
Published: December 2017

The total evaporative water loss, total body water by the direct method and the basal metabolic rate were determined on domestic fowl at various stages of growth. The trials were conducted on a total of 440 birds. The combined respiratory and cutaneous water loss was high on the 1st day of life, dropped to a minimum between 1 and 2 weeks of age, rose sharply at 2–4 weeks of age, then gradually tapered off to the value observed in the adult. The total body water and the total body water on a fat-free basis was quite high on the 1st day of life, then gradually decreased to that of the adult. The basal metabolic rate was low on the 1st day, rose sharply to a maximum at 2–4 weeks of age and then gradually tapered off to that of the adult.
Capillary Permeability to Macromolecules: Stretched Pore Phenomenon
Authors: Shirley H. H. , Wolfram C. G. , Wasserman K. , Mayerson H. S.
Published: December 2017

Radioactive iodinated serum albumin and dextran fractions of average molecular weights of 51,000– 255,000 are injected into nembutalized dogs, and concentration changes of these substances are followed in plasma and thoracic and right duct lymphs for 4–6 hours. At this time, when a ‘steady state’ has been established between plasma and lymph, the plasma volumes of the dogs are increased by the infusion of 40 ml/kg of 5% serum albumin in 0.9% saline solution. This results in a significant and striking increase in the concentration of the injected radioactive iodinated albumin and dextrans in right duct and thoracic duct lymph in spite of increased lymph flows. The increase in dextran lymph/plasma concentration ratios occurs with all molecular weight fractions. These results are interpreted as reaffirming our previously formulated concept that infusions producing plasma volume expansion decrease the resistance of the capillary wall to the passage of macromolecules or increase the size of the capillary ‘pores.’ The concept of capillary permeability as a function of ‘pore’ size must, therefore. be modified to include a labile capillary ‘pore’ size, subject to change with variations in plasma volume as well as other factors.
Diffusion of Aldolase From Rat Skeletal Muscle An Index of Membrane Permeability
Authors: Zierler Kenneth L.
Published: December 2017

It was shown previously that a protein, aldolase, flows from excised rat diaphragm incubated in a variety of media. Because muscle fibers are cut in this preparation there was some question about the absolute values of permeability of the diaphragm. These experiments have been repeated using a small muscle with two tendinous insertions, the peroneus longus. In addition to confirming increased permeability during anoxia, glucose lack, altered metabolism produced by transferring muscle to fresh media, and probable membrane depolarization by potassium, it was shown that there is no greater permeability in phosphate buffer than in bicarbonate buffer and that the aldolase in the effluent (as percentage of total muscle aldolase) decreases as the weight of muscle increases. The latter relation is predicted approximately from surface/volume ratio of cylindrical fibers which decreases as volume increases.
Volume and Electrolyte Homeostasis During Antidiuresis
Authors: Schlegel J. U. , Stone H.
Published: December 2017

Normal rats were were given a 60-cc water load over a period of 12 hours. Antidiuresis due to administration of Pitressin tannate could be overcome by substituting the 60-cc water load with a 60-cc 2% sodium chloride solution or 4.2% urea solution. In animals with sodium retention resulting from previous sodium chloride restriction or short-term adrenalectomy, or both, antidiuresis with maintenance of homeostasis in regard to sodium chloride and water during a 60-cc volume load could be overcome only by making the volume load an approximate 4.2% urea solution. Administration of 60 cc of 2% sodium chloride solution to such animals resulted in pronounced increase in serum sodium and chloride concentrations, often with fatal outcome. Adrenalectomized rats have a decreased ability to perform tubular work in regard to reabsorption of water, as well as of solutes.
Cardiovascular Functions Under Chloralose-Urethane and 21-Hydroxypregnane-3,20 Dione Sodium Succinate (Viadril)
Authors: Greisheimer Esther M. , Ellis Dorothy W. , Stewart George H. , Makarenko Lydia , Oppenheimer M. J.
Published: December 2017

Fifty-five determinations of cardiovascular functions were made on eight dogs under chloralose-urethane anesthesia and forty-one on six dogs under 21-hydroxypregnane-3,20 dione sodium succinate (Viadril). No preanesthetic medication was used. Cardiac output was determined by the dye dilution technique, using the cuvette oximeter. Blood pressure was determined by strain gauge. The mean values found under chloralose-urethane were: cardiac index 4.08, mean blood pressure 146 mm Hg, peripheral resistance 5709 dynes/sec/cm–5, heart rate 149 beats/min. and stroke index 27 cc. The mean values found under 21-hydroxypregnane-3, 20 dione sodium succinate were: cardiac index 5.15, mean blood pressure 104 mm Hg, peripheral resistance 3997 dynes/sec/cm–5, heart rate 172 beats/min. and stroke index 29 cc. When successive determinations were made within a short period of time, the cardiac index and stroke index increased, peripheral resistance decreased and blood pressure and heart rate remained fairly steady.
Pulmonary Ventilation Studies on Pontile and Medullary Cats
Authors: Ngai S. H.
Published: December 2017

Oxygen consumption, arterial blood ph, CO2 tension and O2 saturation were determined in pontile decerebrate cats with normal respiration and apneustic respiration and in medullary cats with rhythmic respiration. Respiratory acidosis is observed regularly during apneustic respiration. In medullary animals, respiratory acidosis also occurs if the respiration is slow or shallow. The O2 consumption is not changed and a reasonable arterial blood O2 saturation is maintained. This is probably attributable to the fact that these animals are breathing oxygen-rich mixtures. Ten per cent CO2 inhalation increases the amplitude of the inspiratory spasm and accelerates the apneustic cycle. This response persists after carotid denervation. Stimulation of the carotid chemoceptors with intracarotid injection of sodium cyanide also accelerates the apneustic cycle. It is concluded that although the afferent impulses from the carotid receptors can modify the activity of the apneustic center, they are not to be considered essential for the production of the apneusis. The underlying mechanism for the cycling in apneustic respiration is not clear from the present study. It appears that this cycling is probably not related to the low O2 tension but rather to the increased CO2 tension in the arterial blood.
Respiratory and Circulatory Vagal Reflexes in Rabbits Exposed to High Explosive Shock Waves
Authors: Clemedson Carl-Johan
Published: December 2017

Changes in respiration and heart rate were studied in rabbits which were exposed to high explosive shock waves in a detonation chamber after bilateral cervical vagotomy, or after pulmonary vagal denervation with the innervation of the sinoaortic region and heart left intact. The rapid shallow breathing occurring after the detonation in nondenervated animals was almost completely absent after cervical vagotomy or pulmonary vagal denervation. Sometimes an often very long period of apnea preceded the tachypnea after the detonation in the control animals. In the denervated animals, especially in the pulmonary vagally denervated ones, apnea was rare or of only very short duration. The bradycardia that can be prevented by bilateral cervical vagotomy, was not elicited by reflexes from the lungs, as the heart rate was lowered to the same extent in the lung vagus denervated as in the control animals. A cardiac standstill or severe distortions of the ECG waves during the first 1–3 seconds after the detonation were common in the nondenervated and in the lung vagus denervated animals but were rare in animals in which bilateral cervical vagotomy had been made.
Effects of Repeated Bleedings on Serum Glycoprotein Concentrations in the Guinea Pig
Authors: Weimer Henry E. , Quinn Frances A. , Nishihara Hisako
Published: December 2017

Effects of repeated bleedings on the serum concentrations of total glycoprotein, seromucoid, albumin polysaccharide, globulin polysaccharide, total protein, albumin and globulin and on the hematocrit and hemoglobin values of blood were investigated in adult male guinea pigs. Significant increases occurred in the seromucoid fraction and in the carbohydrate and protein moieties of the globulin fraction. Significant decreases occurred in albumin polysaccharide, hemoglobin and hematocrit values. Statistical comparisons of the final values of the experimental group with those of a control group subjected to the same experimental procedures but without major blood loss were significant for total protein, albumin, hemoglobin and hematocrit. The conclusion was drawn that the alterations which occurred in the serum glycoprotein concentrations were not due primarily to blood loss.
Heart Rate of Chickens as Influenced by Age and Gonadal Hormones
Authors: Ringer Robert K. , Weiss Harold S. , Sturkie Paul D.
Published: December 2017

The average heart rate of the chick increases from 286 beats/min. at 1 day to 475 at 1 week, with the greatest change occurring during the first 3 days. Heart rate continues to increase slowly to a maximum of approximately 500 beats at 3–4 weeks, then declines gradually to a stable adult level between 280 and 350 at about 6 months. Between the 12th and 17 weeks, the heart rate of the male dropped 10–12% below that of the female, approximating the sex difference found in adults. Heart rate measurements on gonadectomized and gonadotrophin treated birds failed to indicate the role, if any, of gonadal hormones in the development of the sex difference in heart rate.
Pancreatectomy Diabetes in the Rat as Influenced by Strain, Age and Sex
Authors: Beach Eliot F. , Cullimore Owen S. , Bradshaw Phoebe J.
Published: December 2017

Partial pancreatectomy was performed on young and adult rats of the Wistar and the Osborne-Mendel strains. All operations were done by the same operator to minimize effects of variation in technique. Observation of the resulting alterations in glucose metabolism revealed: a) strain difference. Osborne-Mendel animals were frequently made diabetic but Wistar animals never; b) sex difference. Males developed diabetes with four times the frequency of the females, a sex difference opposite to that found in alloxan diabetes production; c) age difference. Surgery in the immature animal was much more often successful in producing diabetes than it was in the adult.
Aphagia in Chickens
Authors: Feldman S. E. , Larsson S. , Dimick M. K. , Lepkovsky S.
Published: December 2017

Aphagic chickens have been produced with electrolytic lesions placed stereotaxically in the diencephalon. These chickens were maintained by introducing food into their crops through a tube. They were inactive and lost much of the ‘nervous’ temperament of White Leghorn chickens. One or more of these chickens showed additional disturbances: impaired gastrointestinal motility, temperature regulation, adipsia and abnormal body composition.
Acid-Base Balance and Removal of Injected Calcium From the Circulation
Authors: Freeman Smith , Jacobsen Anne B. , Williamson Billy James
Published: December 2017

A study was made of the effect of acute disturbances in acid-base balance in otherwise healthy adult dogs, on the rate of removal from the circulation of injected calcium (15 mg/kg). A marked increase in the rate of removal of injected calcium was observed to occur in all animals having high plasma bicarbonate values, except those with respiratory acidosis. The most rapid removal of injected calcium, approximately five times the normal rate, occurred in animals with alkali excess compensated by the inhalation of high concentrations of carbon dioxide. The accelerated removal of injected calcium could not be accounted for by increased excretion in the urine. These animals had essentially normal blood ph values. The calcium space was reduced in ammonium chloride acidosis, but the slope of the disappearance curve for calcium was normal. Carbon dioxide excess was accompanied by an elevation of the plasma concentration of inorganic phosphate.
Ventilatory Responses of Rats to Electrical Stimulation in CO2 Containing Atmospheres
Authors: Yamamoto William S.
Published: December 2017

Steady state measurements of metabolic gas exchange, ventilation and body temperature were made in anesthetized (urethane) Wistar rats breathing gas mixtures in compositions ranging from 20 to 30% oxygen, 0 to 10% carbon dioxide, and nitrogen. Metabolic rate was caused to vary by interrupted electrical stimulation of limb muscles. From 218 such determinations a regression was calculated, Vcoco2 = 0.00843 V (0.999Fe – Fi) – 0.091. It is concluded that the coco2 exchange of rats is similar to those reported in man and dog. Particular care was taken to assure a steady (constant) state at the time of measurement. Homeostatic defense against internally produced CO2 is good, whereas that against environmental CO2 changes is poor.
Water Flux Rates Across Dog Gallbladder Wall
Authors: Grim Eugene , Smith Grafton A.
Published: December 2017

Net and one-way flux rates of water across the dog gallbladder wall were measured by filling the organ with D2O enriched sodium chloride solutions of different osmotic activities and observing changes in volume and isotope concentration. Net flux rates out of the organ were found to be inversely proportional to the sodium concentration of the lumenal fluid, being 86 µl/min. at 70 mEq/l., zero at 220 mEq/l. and –121 at 421 mEq/l. One-way outflux rates decrease with increasing sodium concentration but not linearly; values of the order of 200–260 µl/min. were found. One-way influx rates are equal for hypotonic and isotonic solutions, but nearly double for hypertonic fluid. Comparison was made of water flux rates across the gallbladder wall with published data on dog ileum and urinary bladder, all appropriately corrected for mucosal surface area. On this basis, gallbladder mucosa seems to have the greatest absorptive capacity, and gallbladder and urinary bladder both seem to have greater permittivity to water than the ileum. The apparent higher water permittivity and absorptive capacity of ileum must be attributed to a much greater total mucosal surface area.
Effects of Glucagon on External Secretion of the Pancreas
Authors: Necheles H.
Published: December 2017

In acute experiments with anesthetized dogs, the intravenous injection of medium and large doses of glucagon produced a triple modification in pancreatic juice secretion. The secretion rate was first transiently augmented, then was distinctly and persistently depressed, then finally returned to control values. The initial acceleration in secretion corresponded to the greatly increased arteriovenous blood sugar differences produced by the glucagon. The subsequent depression in secretion usually began while the A-V differences were still elevated. Return of secretion to control values coincided with return of A-V blood sugar differences to control values.
Body and Organ Weights of Rats During Acclimatization to an Altitude of 12,470 Feet
Authors: Timiras Paola S. , Krum Alvin A. , Pace Nello
Published: December 2017

Body and organ weights of sea level control rats were compared with those of rats (P) born at sea level and then exposed to 12,470 feet, and with those of rats (F2) of the second filial generation born and maintained at altitude. Body weight was significantly lower from the fifth day of age in the F2 rats than in either control or P animals. The P rats exhibited normal weight gains in the period from 1 week to 6 months at altitude; however, they showed weight loss 72 hours after reaching altitude and again after 7–10 months of exposure. Elevated hemoglobin and hematocrit values were accompanied by marked cardiac hypertrophy in all F2 rats. In the P animals hemoglobin and hematocrit values were elevated after 2 months of exposure and reached a plateau after 6 months; moderate cardiac hypertrophy was present only after 10 months at altitude. Adrenal weight was markedly increased in all P animals but not in the F2 rats. In the P rats at altitude for 24 and 72 hours adrenal enlargement was accompanied by thymic and lymphatic atrophy. Significant changes were not observed in the liver, kidneys, hypophysis, thyroid, testes and preputial glands.
Effect of Low Electrolyte Feeding on Development of Potassium Deficiency
Authors: Holliday Malcolm A. , Segar William E.
Published: December 2017

Rats fed a diet deficient in sodium, potassium and chloride were observed for 3, 6, 12, 28, 60 and 110 days. Urine excretion of these ions was observed during the initial adjustment to the diet. Serum and muscle electrolyte composition was determined at the end of each interval. Initially the loss of sodium and chloride constituted a loss of extracellular volume without change in concentration. The loss of potassium in this period resulted in a decrease in the intracellular concentration of potassium. Subsequent conservation of all three substances was very effective. No alkalosis developed during the first 28 days on the deficient diet despite an 18% reduction in muscle potassium concentration. A minimal increase in muscle sodium concentration was observed at this level of potassium deficiency. Evidence indicates that this minimal increase was not a function of the low sodium intake per se but rather was characteristic of the magnitude of potassium deficiency, since a similar minimal increase in muscle sodium occurs when an adequate sodium intake is provided.
Effect of Hypothermia on the Cellular Respiration of Ventricular Tissue
Authors: Hannon John P. , Covino Benjamin G.
Published: December 2017

The respiration of ventricular slices and homogenates in the presence of various substrates was studied in control normothermic and experimental hypothermic rats. The Qoo2 of the slices prepared from rats cooled to a rectal temperature of 15°C was significantly higher than that of control normothermic animals. No difference in the rate of oxidation of ventricular homogenates was observed between the two groups except when no substrate was used or when pyruvate was added as the test substrate. In the absence of substrate, there was a tendency toward higher rates in the hypothermic group, whereas addition of pyruvate caused a significant depression in the oxygen consumption of this group. Addition of malate to the pyruvate containing medium produced a marked increase in respiratory rate. The data obtained indicate that hypothermia does not have any adverse irreversible effect on the function of the tricarboxylic acid cycle and its associated enzyme systems. The results do suggest a possible alteration in membrane permeability, an accumulation of reduced intracellular intermediates, or both as a result of the hypothermic episode.
The Steroid Feedback Mechanism
Authors: Schapiro Shawn , Marmorston Jessie , Sobel Harry
Published: December 2017

The mechanism whereby high blood levels of the adrenal cortical hormones inhibit the secretion of ACTH following stress has been investigated. The 4-hour change in circulating eosinophils was used as criterion for ACTH secretion. DCA administration into intact rats prevented the endogenous mobilization of ACTH following stress. When the venous brain blood from the stressed hypophysectomized rat was injected into these DCA-treated intact rats, a discharge of ACTH occurred in the recipients as indicated by a pronounced 4-hour eosinopenia. Carotid artery blood from stressed hypophysectomized rats was relatively inactive in provoking ACTH secretion when injected into intact DCA-treated recipients. If DCA is administered to the hypophysectomized donor rat, its brain blood contains no, or only slight, pituitary stimulating activity. It is concluded that at least one mechanism whereby high levels of the adrenal cortical hormones inhibit the release of ACTH following stress is by blocking the secretion from a cerebral structure, presumably the hypothalamus, of a pituitary stimulating substance (s).
Functional Studies of the Calf Adrenal Cortex Following Total-Body Exposure to a Single Lethal Dose of γ-Radiation
Authors: Rosenfeld George
Published: December 2017

The influence of a lethal dose of whole-body γ-radiation (600 r) on adrenocortical function was investigated by removing the adrenals of irradiated calves at various intervals after exposure, and perfusing the exposed and control glands with an oxygenated artificial medium containing either steroid substrates or ACTH. The functional capacity derived from the ACTH studies was evaluated in three ways: 1) maximum 2-hour corticoid output, 2) maximum output/gm adrenal tissue and 3) maximum output/kg body wt. Within 24 hours after exposure, the irradiated glands revealed increases in these indices of 64, 48 and 71%, respectively. Following this initial rise, their biosynthetic capacity declined to normal levels by about the 4th day before increasing again preterminally. However, the preterminal maximum output per gram tissue (253 µ/gm) was substantially less than the 24-hour postirradiation value (313 µ/gm). A marked terminal depletion occurred prior to death, as evidenced by the mean decrease of 49% in the maximum output per gram tissue of the exposed glands. At this time, their maximum corticoid output and output per kilogram body weight were diminished only 23 and 6%, respectively. The absence of an abnormal biogenetic pattern in response to maximal corticotrophic stimulation (ACTH studies) and of a differential depletion in any of the specific biosynthetic enzymatic systems examined (steroid substrate studies) demonstrated that adrenocortical dysgenesis did not occur despite the development of generalized sepsis, toxemia, hemorrhage, anemia and the other severe disturbances associated with radiation sickness death.
Iodine Metabolism in Pregnancy
Authors: Feldman Joseph D.
Published: December 2017

The metabolism of I131 was studied in 6–8, 13–15, and 19–21 day gestating rats. During pregnancy renal excretion of I131 was significantly increased and thyroidal accumulation of the isotope was significantly depressed, compared with control values. Radiochromatographic studies of nonhydrolyzed and hydrolyzed thyroids and of serum from pregnant and control animals revealed no qualitative or quantitative differences among the radioactive compounds isolated. The metabolism of radiothyroxine (Tx*) and radiotriiodothyronine (Trit*) was studied in 10–15 day gestating thyroidectomized and control animals. The disappearance rate of Tx* from serum was significantly faster in pregnant rats than in controls. The disappearance rate of Trit* from serum was the same in pregnant and control animals. During pregnancy in the rat there is a depletion of iodine and iodine-containing compounds and no evidence for enhanced thyroidal function was found to compensate for this depletion. The situation in rat pregnancy is not applicable to that in human pregnancy.
Salivary Glucose Threshold
Authors: Langley L. L. , Gunthorpe C. H. , Beall W. A.
Published: December 2017

There is no glucose in the parotid saliva of normal, untreated dogs. Glucose appears in the saliva when the blood sugar is elevated to about 512 mg%. If insulin is given along with the infusion of glucose, the threshold is elevated to approximately 1235 mg%. Conversely, in alloxan diabetic dogs there is glucose in the saliva at the fasting blood sugar level. In this series that level averaged 269 mg%. Apparently the passage of glucose from the blood to the saliva is more than a simple permeability function. Glandular intracellular carbohydrate metabolism may be involved.
Metabolism of Insulin-I131 in the Extrahepatic Tissues
Authors: Drury Douglas R. , Karasek M. A. , Britton B. , Wick Arne N.
Published: December 2017

Insulin-I131 is rapidly degraded after injection in the intact animal. The process is also rapid in the eviscerated animal with kidneys. Degradation is relatively slow in the eviscerated-nephrectomized preparation, so that it can be used to study the manner of distribution of injected insulin-I131. It takes about an hour for this compound to become evenly distributed in the body and then it appears to be contained within the extracellular compartment. In the eviscerated animal biological activity of injected insulin-I131 parallels the concentration of the compound in the plasma except during the 1st hour while it is still passing from plasma to tissue fluid.
Enhancement of Phosphatide-Induced Hypercholesteremia by Prior Ingestion of Cholesterol and Triglyceride
Authors: Friedman Meyer , Byers Sanford O.
Published: December 2017

Rats fed stock diet enriched with 2% cottonseed oil and 2% cholesterol for 3 days prior to intravenous infusion with phosphatides showed a hypercholesteremic response to the infusion which was significantly greater than that of rats fed a diet enriched in cottonseed oil only. The latter animals showed the same hypercholesteremic response as rats maintained on a fat and sterol-free diet. During infusions, the average plasma phospholipid concentrations of the three groups was the same.
Hematopoietic Recovery Induced by Bacterial Endotoxin in Irradiated Mice
Authors: Smith Willie W. , Alderman Ilo M. , Gillespie Ruth E.
Published: December 2017

Mice given an intraperitoneal injection of Salmonella typhosa endotoxin 24 hours before irradiation showed an advance in the recovery of granulocytes, platelets and hemoglobin, with the effect on lymphocyte counts relatively small. Differences in bone marrow cellularity and in ability to mobilize granulocytes were particularly striking. Effects of an injection given after irradiation although significant were less pronounced. The induction of hemopoiesis is thought to be responsible for the increase in survival previously observed with this treatment. It is not known whether the action of endotoxin upon the precursor cells is direct or indirect.
Relationship Among Recovery Oxygen, Oxygen Missed, Lactate Production and Lactate Removal During and Following Severe Hypoxia in the Unanesthetized Dog
Authors: Alpert Norman R. , Kayne Herbert , Haslett Winona
Published: December 2017

An experiment was designed to test the ‘O2debt’ hypothesis. Oxygen consumption and plasma lactate were measured before, during and following hypoixa in unanesthetized spinally transected dogs. The O2 consumption was depressed during hypoxia and returned toward control levels during recovery. Lactate levels increased during the hypoxia and returned to the control during recovery. Oxygen missed was correlated with the excess consumption of recovery. A highly significant relationship was found which indicated that the larger the depression in O2 consumption during hypoxia, the greater was the depression during the recovery period and the more prolonged the return to control levels. Oxygen missed during hypoxia was compared to lactate production. A significant relationship was found. Lactate removal was compared to excess consumption of recovery. No correlation existed between lactate removal and recovery O2 consumption. The authors postulate the presence of a metabolic governor which controls the rate of O2 uptake.
Characteristics of Acidic Urine After Loading With Weak Organic Acids in Dogs
Authors: Brodsky William A. , Miley John F. , Kaim John T. , Shah Nareshchandra P.
Published: December 2017

Hydropenic, anesthetized dogs were given loading infusions of 0.5 m lactic acid and beta-hydroxybutyric acid with and without mannitol. In some experiments blood was collected from the femoral artery, and urine from the bladder. In other experiments, blood was collected from the renal vein, and urine from the renal pelvis. In serum, pH and CO2 content fell to values as low as 6.7 and 4 mm/l., respectively. Urine flow reached maximal levels of 1.5–2.5 cc/min. after lactic acid alone, and 4.0–6.0 cc/min. after mannitol plus lactic acid. The pattern of osmotic activity versus urine flow was characteristic of a nonspecific type of osmotic diuresis. Titratable acid excretion increased to levels of 9–72 µm/min. Loading solute contributed to the bulk of the observed titratable acid even though its pKa was 1–2 u below the usual urinary pH. In urine, pH and CO2 content were reduced to levels of 4.76 and 0.64 mm/l., respectively. Calculated value of CO2 tension of urine was greater than that of plasma in 106 observations; was less than that of plasma in 33 observations; and was equal to that of plasma in 25 observations. Tonometric measurements were made on standard solutions and on samples of urine and plasma of two dogs during lactic acid acidosis. Tonometrically determined values of pCO2 agreed (to within 1 mm of Hg) with calculated values of pCO2.
Occurrence of Phosphate Exchanges in Muscular Contraction
Authors: Dixon Glen J. , Sacks Jacob
Published: December 2017

No change in the concentrations of ATP and ADP was found to result from 30 seconds of tetanus of the cat gastrocnemius muscle under essentially anaerobic conditions. Tracer data obtained indicate that there is no redistribution of phosphate between the terminal P of ATP and phosphocreatine, such as would be anticipated if resynthesis of ATP took place by transfer of the phosphate group of phosphocreatine. No evidence was found for equilibration of the isotope between the terminal and middle P's of ATP and the terminal P of ADP, such as would be expected if the myokinase reaction played any significant part in the synthesis of ATP. Little or no AMP was found in either resting or tetanized muscles. The specific activities of the terminal P of ATP and of glucose-6-phosphate remained significantly different at the end of the contraction period. If the formation of lactic acid took place by way of the classical Embden-Meyerhof pathway, then a redistribution of the tracer, with resulting equality of specific activities between these two P groups, would be anticipated. From all these results it is concluded that the energy for contraction is furnished by some other means than the dephosphorylation of ATP.