bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiologic aspects of microwave irradiation of mammals
Authors: Michaelson Sol M. , Thomson Roderick A. E. , Howland Joe W.
Published: December 2017

Dogs, rabbits, and rats exposed under controlled conditions to pulsed 2800 Mcycle/sec microwave (radar) radiation display characteristic physiologic responses, some of which are related to heating of superficial tissues. Specific changes in leukocyte levels occur which are independent of hematocrit or temperature increase. Postexposure lymphocytopenia and eosinopenia appear related to duration of exposure. Anesthetization of the dog results in an increased thermal susceptibility which is not evident in the rabbit or rat. Consumption of water during exposure depresses the thermal response. Exposure at increased ambient temperature results in a synergism of thermal effect reducing the tolerance to microwaves. Vasomotor integrity appears to be a critical factor in regulating the thermal response to microwaves. No specific long-term effects such as cataracts have been observed in animals held for more than 1 yr postexposure.
Effect of acidity on blood coagulation
Authors: Crowell Jack W. , Houston Bobby
Published: December 2017

Various methods were used to determine the effect of decreasing the pH on the coagulation of whole blood. It was found that injection of lactic acid into the slowly moving blood of an A-V shunt caused death in dogs much faster than the same rate of acid injection into the fast-moving blood of the aorta. Also, it was found that lowering the pH of withdrawn heparinized blood made it toxic upon reinjection, whereas blood withdrawn and not treated, treated with the neutralized acid-base mixture, or to which a larger amount of heparin had been added was not toxic upon reinjection. Heparinized blood withdrawn from a dog and to which various amounts of lactic acid were added showed a decrease in its clotting time as the pH became lower and lower. Below a pH of approximately 6.7, the heparinized blood coagulated almost as rapidly as nonheparinized blood. Finally, it was found that there was clotting in ligated vascular tubes of dogs after lowering the pH of the blood, whereas no clotting occurred in vascular tubes ligated before the acid was given or after the pH of the dog blood had returned to normal. Emphasis is placed on the fact that the decrease in pH in dogs subjected to circulatory arrest is associated with intravascular clotting.
Electrical activity of the isolated nerve-urinary bladder strip preparation of the rabbit
Authors: Ursillo R. C.
Published: December 2017

The electrical activity of single cells of the smooth muscle of the isolated pelvic nerve-bladder strip preparation of the rabbit has been recorded by means of KCl-filled glass capillary microelectrodes. It was found that increasing the tension on the muscle either by stretching or by the addition of carbachol (3 µg/ml) to the bathing fluid causes a concomitant depolarization of the cell membrane. Spontaneous electrical activity and that elicited by stimulation of the nerve were similar and consisted of slow waves of depolarization of a 3–5 sec duration and spikes superimposed upon the depolarization phase of the slow wave. The spikes varied from 5 to 35 mv with no overshoot. Excitability of cells varied from one in which no response to tetanic stimulation of the nerve was seen to one which exhibited a series of spikes to a single shock. It was shown that slow waves and spikes could occur out of phase with the dominant activity of the whole muscle. Latency to a single shock to the nerve was found to be quite consistent for the same cell. However, a marked variation in latency was found among different cells of the same preparation.
Effect of hemorrhage on cardiac output of sympathectomized dogs
Authors: Chien Shu , Billig Stuart
Published: December 2017

Blood volume, cardiac output (C.O.), and arterial pressure were measured in unanesthetized, sympathectomized dogs before and after various degrees of hemorrhage. The posthemorrhage cardiac output, expressed as a percentage of the control, showed a linear relationship with the per cent reduction in blood volume (Vr), (C.O. = 107 – 2.51 Vr). After a moderate hemorrhage, the per cent decrease in the arterial pressure was less than that of the cardiac output, indicating a rise of peripheral resistance. This is attributed mainly to the distensibility of the vascular wall. After more severe hemorrhages, the peripheral resistance tended to decrease, due probably to the reduction in hematocrit and the accumulation of metabolic products. By analyzing the volume-flow-pressure relationship in sympathectomized dogs, one can quantify the various compensatory adjustments to hemorrhage. When the blood volume is reduced by less than 10%, the arterial pressure is maintained primarily by the nonneural factors. With a volume reduction between 10 and 25%, the sympathetic activity, the inhibition of vagi, and the nonneural factors are of about equal importance. When the reduction of blood volume is greater than 25%, the sympathetic activity becomes the most significant compensatory factor.
Hyperplasia after unilateral nephrectomy and role of excretory load in its production
Authors: Simpson David P.
Published: December 2017

Using P32 uptake in DNA nucleotides as an index of mitoses, hyperplasia in the kidney has been studied in rats both after unilateral nephrectomy and after transplantation of one ureter into the peritoneal cavity. In the latter group, in which the excretory load on each kidney was increased without removing any kidney tissue, no increase in P32 uptake was present 48 hr after operation, whereas in unilaterally nephrectomized animals the P32 uptake was doubled at this time, compared to control animals. These results are interpreted as indicating that the increased work load on the remaining kidney after unilateral nephrectomy is not responsible for stimulating cell division. It is suggested that hyperplasia under these conditions is probably a result of the decrease in the number of kidney cells per se.
Serum enzyme changes in dogs exposed repeatedly to severe altitude hypoxia
Authors: Highman Benjamin , Altland Paul D.
Published: December 2017

Blood values were determined on dogs exposed to a simulated altitude of 32,000 ft for 4 hr five times weekly for 7 weeks. Serum glutamic oxalacetic transaminase and serum lactic dehydrogenase values showed a gradual increase during the 7 weeks, while serum glutamic pyruvic transaminase values stabilized by the 2nd week at slightly above initial normal values. Serum alkaline phosphatase and serum aldolase values stabilized after the 3rd week at two to three times the initial values. After cessation of exposures, values dropped sharply during the first 2 weeks and slowly approached normal values at the end of 6 weeks. A subsequent single 4-hr exposure to 32,000 ft evoked the usual transient sharp rise in serum enzyme values, but not the typical hyperglycemic response, observed before the acclimatization. Terminal pathologic studies revealed minor residual lesions, attributable to the repeated exposures, which may account in part for the slow restoration of normal values after cessation of exposures.
Glucose biokinetics in sheep
Authors: Kronfeld D. S. , Simesen M. G.
Published: December 2017

The transfer rate of the glucose pool in sheep was estimated by methods using labeled glucose. Transfer rates ranged from 0.28 to 0.39 g/hr/kg3/4 when estimated 1 or 16 hr after feeding, but were only 0.18 and 0.20 g/hr/kg3/4 when estimated 96 hr after feeding. Comparable values calculated from data in the literature for rats, dogs, and man range from 0.25 to 0.40 g/hr/kg3/4 at 16 hr after feeding, although they are higher for rats only 4 hr after feeding (0.89 g/hr/kg3/4). Comparison of postabsorptive values (4 hr in rats, 16 hr in sheep) or fasting values (16 hr in rats, dogs, and man, 96 hr in sheep) suggests that the over-all rate of glucose metabolism is lower in sheep.
Dopa uptake and catecholamine content in heart and spleen
Authors: Wegmann A. , Kako K. , Chrysohou A.
Published: December 2017

dl-Dopa has been infused in mongrel dogs under various conditions in order to study its uptake and its influence on the storage of norepinephrine and epinephrine in the heart and spleen. Catecholamines and dopa were estimated with the trihydroxyindole method after separation with Amberlite. No increase in norepinephrine and epinephrine content in the heart and spleen could be detected after dopa infusion. Apparently, the rate of conversion of dopa into norepinephrine does not depend on the supply of the substrate.
Cardiovascular effects of radioprotective compound beta-aminoethylisothiuronium Br-HBr (AET)
Authors: Knott David H. , Overman R. R.
Published: December 2017

The radioprotective compound beta-aminoethylisothiuronium Br-HBr (AET) produces marked cardiovascular changes in various mammals. This problem was investigated in the dog by the slow intravenous infusion and the rapid intravenous injection of AET. Blood pressure, electrocardiogram, and cardiac output were measured, and peripheral resistance, plasma and blood volumes, stroke volume, and modal circulation time were subsequently determined. A dominant response noted in this study was a marked hypertension induced by the slow infusion and rapid injection of AET. This alteration was due to an increased peripheral resistance. In addition, a rapidly developing hypotension following a hypertensive peak was observed in animals which were rapidly injected with AET. It was also noted that the myocardium was refractory to vagal stimulation after AET administration. The action of this compound appears to be a direct one on the peripheral vasculature and the myocardium.
Myocardial creatine phosphate and nucleotides in anoxic cardiac arrest and recovery
Authors: Benson Ellis S. , Evans Gerald T. , Hallaway Ben E. , Phibbs Clifford , Freier Esther F.
Published: December 2017

In isolated perfused dog hearts, myocardial concentrations of creatine phosphate (CrP) and adenosine triphosphate (ATP) decreased following a 45-min period of anoxia. After partial resuscitation by perfusion of oxygenated blood for 30 min, CrP had risen again to approximately control values but ATP concentration had fallen lower. Increased concentrations of deaminated derivatives of ATP, chiefly inosine, were found in the myocardium and in the perfusion effluent after anoxia. The myocardial inosine was still elevated after resuscitation. We conclude that the dynamic equilibrium involving breakdown and resynthesis of ATP through deamination and reamination is disturbed by periods of anoxia as carried out in these experiments and, in addition, inosine is lost by diffusion into extracellular compartments.
Development of renal tubular transports of TEA and PAH in the puppy and piglet
Authors: Rennick Barbara , Hamilton Byron , Evans Robert
Published: December 2017

Simultaneous accumulations in renal cortical slices of tetraethylammonium and p-aminohippurate were studied. Slices were obtained from fetal puppies and newborns. Newborns were sacrificed at intervals from birth to 9 weeks. Slice-to-medium ratios (S/M) were compared for adult, pregnant, and postpartum dog renal slices. Newborn piglets' kidneys were studied similarly. It was found that these two transport systems developed independently in the fetal and newborn puppy. The transport of TEA was low at birth and progressively rose to the adult value at 9 weeks. The PAH transport system was active in fetal and newborn tissues. Transports of both TEA and PAH were absent under anaerobic conditions. Acetate stimulated TEA and PAH slice uptakes to the same extent as in the adult. In the piglet the surface slice of the kidney showed low transports of TEA and PAH for the first 2 weeks. At 4 weeks both transport systems increased to equal those in the slices of the lower cortex. The lower cortical slices accumulated TEA and PAH from birth to 8 weeks of age at a fixed rate. The TEA S/M in the piglet at birth was more than twice that in the dog. PAH was accumulated in a predominantly conjugated but unidentified form in the piglet kidney slice.
Absorption of inhaled water in experimental pulmonary edema and embolism
Authors: Starzecki B. , Halmagyi D. F. J.
Published: December 2017

The effect of pulmonary edema and pulmonary embolism on the rate of absorption of standard amounts of inhaled fluids was investigated in rats. Relative lung weight (= lung weight in per cent of body wt.) was used as an index of the fluid content of the lung. α-Naphthylthiourea (ANTU) was used to induce lung edema; intravenous barium sulfate was used as embolic material. Fresh water (.1 ml/100 g/body wt.) saline, and other fluids were introduced intratracheally; the animals were sacrificed 5 min (fresh water), 5, and 15 min (physiological saline) subsequently. The rate of fluid absorption from the lungs was not affected by ANTU lung edema but was significantly delayed after pulmonary embolism. The implication of these findings is discussed.
Comparative indexes of thyroid function in sheep
Authors: Hoersch T. M. , Henderson H. E. , Reineke E. P. , Henneman H. A.
Published: December 2017

The effects of light and temperature on thyroid activity of sheep were assessed by four methods: thyroid secretion rate, zero time per cent uptake of I131, I131 output half-time, and measurement of the thyroid epithelial cell height. Increased ambient temperature inhibited thyroid activity as evaluated by all methods. Reduced temperatures consistently resulted in a depressed uptake of I131. I131 output half-time had no relationship with actual hormone secretion. Light alterations imposed the same trend on thyroid function when activity was assessed by secretion rate and cell height measurement. As evaluated by these two methods the lowest thyroid activity was observed at 12 hr of illumination per day and increased with both increasing and decreasing light beyond this 1:1 light-to-dark ratio. When the three isotopic measures of thyroid activity were correlated with the histological method the highest correlation was found between cell height and thyroid secretion.
Effects of sex hormone manipulation on audiogenic seizures
Authors: Werboff Jack , Corcoran John B.
Published: December 2017

Albino rats of the Sprague-Dawley strain exhibited an unusual sex incidence to audiogenic seizures, with females more susceptible than males. It was predicted that altering the sex hormone balance by means of surgical intervention or hormonal injection would alter their seizure susceptibility. Male rats were castrated and then received injections of estradiol (100 RU) and progesterone (0.5 mg). Female rats received testosterone (1.0 and 2.0 mg) and were later ovariectomized. Audiogenic seizure tests under two threshold conditions were conducted prior to and during the respective hormonal treatments. Each group was used as its own control. The results indicated that castration of the males had little effect on seizure responses. Estradiol administration resulted in an increase in seizure responses. In the females, testosterone administration and ovariectomy resulted in a decrease in seizure responses. It was concluded that sex hormones either exert a direct effect or mediate the control of audiogenic seizure responses in rats of the Sprague-Dawley strain.
Oxygen metabolism and oxygen debt repayment after myocardial ischemia
Authors: Coffman Jay D. , Gregg Donald E.
Published: December 2017

Coronary blood flow, myocardial oxygen usage, and coronary venous lactate and pyruvate concentrations before and after release of left coronary or left circumflex artery occlusions (10–120 sec) were studied in anesthetized, open-chest dogs. Flow and oxygen theoretical debts were calculated from control blood flow and oxygen usage and compared to the repayments. Flow debts were usually overpaid for all durations of occlusion. Oxygen debts were repaid with an average excess of 1.0 and 3.5 cc after 15 and 30 sec but with a deficit of 0.4 cc for 10-sec left coronary artery occlusions. Excess lactate, as a measure of oxygen debt, was present after 50% of the 30-sec left coronary artery occlusions and after all of the 120-sec circumflex artery clampings. It was demonstrated that ischemia stimulates blood flow and myocardial oxygen consumption and increases oxygen availability. Results indicate that the myocardium can tolerate only brief periods of arterial occlusion but can develop and repay small oxygen debts.
Evidence favoring a cardiac mechanism in irreversible hemorrhagic shock
Authors: Crowell Jack W. , Guyton Arthur C.
Published: December 2017

Shock was induced in 55 dogs by removing blood until the arterial pressure had fallen to 30 mm Hg. The pressure was kept at this level for as long as 10 hr by constantly adding additional blood to the reservoir. The hematocrit was kept constant to prevent large variations in the viscosity. Mean pressures of the right and left atrium, the pulmonary artery, and the systemic arterial system were recorded as well as oxygen consumption and A-V oxygen difference. Total peripheral resistance and cardiac output were calculated. That period of time during which the animal passed from a reversible stage of shock to an irreversible stage of shock was studied. It was found that no significant change occurred in oxygen consumption, cardiac output, or peripheral resistance during this transition phase. However, changes did occur in the operating parameters of the heart. The left atrial pressure began rising with the transition from reversible to irreversible shock and continued rising until death of the animal. It is suggested that irreversible hemorrhagic shock is due to acute cardiac failure.
Virtual absence of turnover in cadmium metabolism: Cd109 studies in the mouse
Authors: Cotzias G. C. , Borg D. C. , Selleck B.
Published: December 2017

Following injection, radioisotopes of physiologically occurring elements are excreted at rates that increase upon metabolic loading with stable carrier. In contrast, Cd109 showed negligible total-body turnover in the mouse regardless of challenges with Cd or Zn, and alimentary absorption occurred irrespective of the body's Cd burden. As opposed to certain bone-seeking nonphysiological radioisotopes which also show this behavior, Cd109 concentrated primarily in nonosseous soft tissue. Intracellularly the distribution of Cd109 resembled that of Zn65, except for a lower uptake of Cd109 by the nuclear fraction. Other dissimilarities between Cd and Zn metabolism included the presence of a well-defined excretory pathway only for Zn and different effects of Cd and Zn carriers upon the organ distribution of Cd109. These findings suggest the following: a) Cd does not obey homeostatic control; b) similarities between Cd and Zn metabolism imply that Cd may function, in part, as an antimetabolite of Zn; c) significant physiological discrimination between Cd and Zn exists, at least at the level of excretory processes.
Red cell and albumin circulations in the ileum
Authors: Swann H. G. , Stegall H. F. , Collings W. D. , Miles N. A.
Published: December 2017

A method for investigating the compartments in an organ through which labeled materials circulate has recently been refined. This was applied to the ileum. Radioactive red cells left the tissue as if they were circulating through a single compartment: its turnover time was 9.5 sec and its apparent volume was 3.7 ml/100 g tissue. But radioactive albumin left the tissue as if it was circulating through three compartments. They lay in parallel. Their turnover times were 10.3, 42, and 370 sec, and their apparent volumes were 6.7, 3.7, and 3.8 ml/100 g. Because the time constants for the red cell compartment and the first albumin compartment are the same, it is thought that this is an intravascular compartment. Its hematocrit ratio is the same as that in systemic blood, indicating that blood flows through the compartment in the same way that it flows through large vessels. The other two albumin compartments, neither of which is penetrated by red cells, are postulated to be interstitial and/or lymphatic-lacteal in nature. This hypothesis is harmonious with the porous character, recently revealed by electron microscopy, of the membranes in these regions.
Effect of amphetamine on food intake in rats with brain-stem lesions
Authors: Carlisle Harry J. , Reynolds Robert W.
Published: December 2017

An examination was made of the role of the area postrema in the regulation of food intake and in mediating the anorexigenic effect of amphetamine. Rats with area postrema lesions lost 13–20% of preoperative weight, and tended to regain only a slight amount of this lost weight. Control lesions in the hippocampus and dorsolateral thalamus produced no significant effect on food intake. It was concluded that the area postrema has a facilitatory effect on food intake. The anorexigenic effect of amphetamine was exaggerated in the area postrema group with 50% or greater damage to the target area only. This area is not, therefore, a primary receptor for amphetamine, but is somehow implicated, since its destruction results in greater drug action.
Plasma free fatty acids in dogs treated with Triton WR-1339
Authors: Scanu Angelo , Szajewski Janusz M.
Published: December 2017

Dogs fed a regular diet were given intravenously 250 mg of Triton WR-1339 (a nonionic surface active agent) every 4th day. When sustained lipemia developed, their plasma free fatty acid (FFA) response to epinephrine and glusose was studied and compared with that of normal animals. The time course of the rise (epinephrine) or fall (glucose) of the plasma FFA was similar in the two groups of animals. The Triton-treated dogs had, however, plasma FFA levels twice as high as normals. Plasma FFA, which in control dogs were bound principally to albumin, were mostly associated in the Triton-treated animals with the low-density ß-lipoproteins. A partial shift of FFA from albumin to ß-lipoproteins could be produced in vitro by addition of Triton to normal canine serum.
Weight gains and fat accumulation in rats subjected to periods of caloric restriction
Authors: Heggeness F. W.
Published: December 2017

It was previously observed that weanling rats subjected to several days of caloric intake just sufficient to maintain weight and then fed ad libitum developed enhanced rates of lipid accumulation. Animals so treated gained weight and accumulated fat at a rate greater than did animals fed ad libitum from weaning. The objective of the present study was to determine the conditions of restricted intake that resulted in the greatest stimulation of lipogenesis and to evaluate the effect of an initially elevated rate of fat accumulation on later body composition. Maximal stimulation of lipogenesis was found to follow 6 days of caloric restriction on a diet high in carbohydrate. Differences in body weight and fat content previously observed after 6 days were not maintained. By the 12th day of ad libitum feeding, body weight and fat content of control animals and those with elevated lipogenesis were the same. Animals subjected to periods of caloric restriction alternating with periods of ad libitum intake showed, during unrestricted feeding, rates of weight gain and fat accumulation greater than that of animals fed ad libitum continuously.
Inhibitory effect of hydrocortisone and analogues on adrenocortical secretion in dogs
Authors: Black William C. , Crampton Richard S. , Verdesca Arthur S. , Nedeljkovic Relja I. , Hilton James G.
Published: December 2017

An isolated perfused adrenal gland preparation in the dog was used to study the effect of perfusion of exogenous steroids on endogenous adrenal secretion. ACTH was infused throughout each experiment to ensure maximal endogenous steroidogenesis. It was found that hydrocortisone and two of its analogues (Δ1-hydrocortisone and Δ1, 9α-fluoro, 16-methyl hydrocortisone) when perfused at concentrations of 100, 200, and 400 µg/ml inhibit the endogenous secretion of hydrocortisone and corticosterone. Corticosterone at the same concentrations inhibited only corticosterone secretion.
Effects of d-mannoheptulose and d-sedoheptulose on blood glucose and ketone bodies in the rat
Authors: Simon Ernst , Scow Robert O. , Chernick Sidney S.
Published: December 2017

The effects of mannoheptulose and its isomer, sedoheptulose, were studied in fasting rats. Mannoheptulose, 400 mg injected subcutaneously, increased blood glucose to 200 mg/100 ml and ketone bodies to 21 mg/100 ml in 1 hr. These effects began to disappear in 2 hr when the blood concentration of mannoheptulose was less than 40 mg/100 ml. Administration of glucose with the heptulose increased the degree of hyperglycemia. Glucose, given alone, lowered the blood ketone bodies in fasting rats; this effect was delayed by mannoheptulose until the concentration of the latter was less than 40 mg/100 ml. Insulin, 1 unit injected subcutaneously, decreased the amounts of glucose and ketone bodies in the blood of fasting rats. Mannoheptulose did not alter the effects of insulin. Mannoheptulose had no effect on blood glucose or ketone bodies in "totally" pancreatectomized rats. The findings suggest that mannoheptulose may act in the pancreas by blocking or suppressing release of insulin. Sedoheptulose did not have any diabetogenic or ketogenic activity; its effect on lowering blood ketone bodies was similar to that after glucose administration.
Time-concentration curves and dilution spaces of T-1824 and I131-labeled proteins in dogs
Authors: Baker Carleton H. , Wycoff H. D.
Published: December 2017

Five-hour time-concentration curves were obtained after injection of T-1824, I131-labeled human albumin, and I131-labeled dog fibrinogen. The albumin and fibrinogen curves can be roughly divided into 3 segments (0–20 min, 20–70 min, and 70–310 min), each showing a different mean slope. The T-1824 curves show only one change in slope, at 20 min. After at least 70 min the dye left the circulation at a much greater rate than either of the iodinated proteins. Thoracic duct lymph return indicated that 12.9% of the injected iodinated albumin, 8.3% of the T-1824, and 6.3% of the iodinated fibrinogen was returned over the 310-min period. The spaces measured by the T-1824 and the iodinated albumin were not significantly different, whereas the fibrinogen measured a significantly smaller space than either of the former. It is inferred that the dye-protein complex might be broken within the vascular system. Also, the loss of fibrinogen from the capillary is less han for the iodinated albumin.
Fate of tritium-labeled carnitine administered to dogs and rats
Authors: Yue Kenneth T. N. , Fritz Irving B.
Published: December 2017

dl-Carnitine hydrochloride, tritiated nonspecifically, was purified and shown to have the same chemical and biological properties as the original compound (ß-hydroxy, γ-trimethylammonium butyrate). About one-third of administered material was excreted in urine during a 7-hr period following the intravenous injection of carnitine HCl (2 mg/kg) to dogs. Tritium not excreted appeared primarily in the trichloroacetic acid (TCA)-soluble fraction of various tissues, with approximately half that administered being found in skeletal muscle. The concentrations of tritium in TCA-soluble fractions of all organs examined except brain were 4–30 times higher than plasma concentrations. No evidence of carnitine degradation was found. The tritiated material in TCA-soluble extracts moved as single peaks in three different chromatographic systems, having the same RF values as those of known samples of carnitine. Tritium in chloroform-soluble fractions accounted for less than 1% of that administered. Of the organs examined, liver had the highest relative amount of incorporation of tritium into lipids, with all activity being found in unidentified phospholipids, chiefly in the lecithin fraction. The possible physiological significance of carnitine in muscle is briefly discussed.
Arterial muscle contraction and potassium movement in vitro
Authors: Headings Verle E. , Rondell Paul A.
Published: December 2017

Rings of dog carotid 2–3 mm in width were placed in a physiological salt solution, equilibrated, under 1 g of tension, at 37 C for 2 hr and were then stimulated electrically or with epinephrine, or norepinephrine. Tension development was recorded. At given time intervals following stimulation, rings were removed and analyzed for potassium content. Maximum loss of potassium, averaging 10% of original content, occurred 5–15 min after electrical stimulation. After stimulation by either epinephrine or norepinephrine a consistent slight increase in potassium content occurred. Thus net potassium efflux (and membrane depolarization?) is not an essential part of vascular muscle contraction in response to catecholamine stimulation. The reported loss of potassium from artery wall following catecholamine stimulation in vivo suggests another, perhaps indirect, action of these agents.
Influence of plasma amino acid level on urine volume in the alligator
Authors: Coulson Roland A. , Hernandez Thomas
Published: December 2017

Growth hormone, hydrocortisone, and a mixture of the two were injected daily into small alligators for periods up to 2 weeks. Although plasma amino acid levels increased only slightly after either growth hormone or hydrocortisone, injection of the combined hormones doubled the concentrations. In all cases increases in plasma amino acids were associated with an augmented renal ammonia synthesis and an increased urine volume. When the degree of hydration was maintained at a nearly constant level, the urine volume was directly related to the quantity of amino acids available for renal deamination. Insulin, a hormone which lowers the concentration of extracellular amino acids, decreased the rate of renal ammonia synthesis and therefore the rate of urine flow. The oliguria produced by insulin could be counteracted by the injection of glycine, a known precursor of urinary ammonia. Evidence is presented which suggests that in the "diabetes" caused by a combined injection of growth hormone and hydrocortisone, protein catabolism is enhanced and fat catabolism is inhibited. A negative nitrogen balance occurred as a result of the delivery of more amino acids for renal deamination.
Cardioaccelerator action of angiotensin
Authors: Nishith S. D. , Davis L. D. , Youmans W. B.
Published: December 2017

Effects of synthetic angiotensin II on heart rate and blood pressure were determined in dogs under the influence of morphine (3 mg/kg) and chloralose (90 mg/kg). Angiotensin in total doses of 2.5–20 µg, rapidly injected intravenously in intact dogs, caused an initial decrease in heart rate followed by a rise above the control level, despite the continued elevation of arterial blood pressure. When the degree of rise in arterial pressure was buffered by a mechanical compensator connected with the abdominal aorta, rapid intravenous angiotensin injection produced no initial cardioinhibitory phase, and the magnitude of the accleration of heart rate was much greater than in the unbuffered animal. Slow intravenous infusion of angiotensin in some cases caused only a rise in heart rate. In sinoaortic denervated animals both blood pressure and heart rate were greatly increased when a total dose of 10 µg angiotensin was rapidly injected intravenously. Thus, it is demonstrated that the cardioinhibitory response to angiotensin depends largely or exclusively on reflex effects from sinoaortic pressoreceptors, and that angiotensin has a strong cardioaccelerator action which is exerted through the efferent nerves to the heart.
Protein composition of denervated muscle
Authors: Stewart Doris M.
Published: December 2017

The protein composition of normal and denervated rat gastrocnemius muscles was determined. In addition, denervated muscles subjected to rhythmical stretching and electrically stimulated denervated muscles were analyzed. In the normal right gastrocnemius 5.33% of the total protein is connective tissue, 29.65% is sarcoplasmic protein, and 65.02% is contractile protein. Fifteen days after denervation, untreated muscles had lost 55.8% of the initial weight and distribution of the protein fractions was different from normal. Connective tissue and sarcoplasmic protein represented larger percentages of the total and contractile protein less of the total protein than in the normal muscle. Rhythmical stretching had no effect on the change in percentage composition which occurred after denervation, but atrophy was significantly retarded. Electrical stimulation was more effective than stretching. By 15 days, the stimulated muscles had lost only 28.3% of the initial weight and protein distribution was more nearly normal than in the stretched muscles.
Calcium homeostatic mechanisms and uptake of radioisotopes in the lobster
Authors: Hayes Dora K. , Singer Leon , Armstrong W. D.
Published: December 2017

Hemolymph calcium levels were decreased by one-half by placing lobsters in artificial sea water containing less than 1 mEq/liter calcium ion. In these animals sodium and phosphate content of dry shell was increased but the shell calcium content was not detecsably altered. Calcium appearing in the bathing medium was apparently derived from two sources. While control animals exhibited a significant ability to select calcium in preference to strontium only in gill and mandible tissue, almost all tissues of hypocalcemic animals showed significant uptake of Ca45 over Sr85. Claw shell acquired more isotope per gram of dry weight than did other calcified tissue. Cesium (Cs134) was not taken up to any great extent by internal soft tissues. Gills contained two to three times as much Cs134 relative to bathing solution as did gills from animals exposed to solutions containing Ca45 and Sr85.
Gonadotropic activity of neonatal pituitary glands implanted in the rat brain
Authors: Knigge Karl M.
Published: December 2017

Pituitary glands of neonatal rats were implanted by stereotaxic methods in various hypothalamic areas of the brains of adult, hypophysectomized male rats. Of 58 implantations, 44 viable grafts composed of pars distalis, intermedia, and epithelioid-like nervosa were found 3 months later. In none of the graft-bearing animals was there any evidence of thyrotropic or corticotropic activity as judged by thyroid or adrenal weight, I131 uptake, or plasma free corticosteroids. In 18 graft-bearing animals, testicular weights ranged from 831 to 2,118 mg, compared to mean testis weight of 165 mg for hypophysectomized, nonimplanted animals. Histological sections of testes from these graft-bearing animals revealed active spermatogenesis. In each implanted animal with testicular maintenance, the pituitary graft was situated in the floor of the hypothalamus, encroaching upon or interrupting fibers of the supraopticohypophyseal tract. Adenohypophyseal cells which appeared to be nearest or more intimately related to these fibers were large (12–20µ), vacuolated, and contained abundant fuchsinophilic granules typical of castration cells. Other chromophil types were not present. In all nonfunctional grafts (situated in preoptic area, septum, anterior hypothalamus, and mammillary region) adenohypophyseal cells were uniformly small and chromophobic.
Influence of age on plasma adrenocorticosteroids in rats, rabbits, and guinea pigs
Authors: Thornton Mary , Hughes Edwin R. , Kelley Vincent C. , Ely Robert S.
Published: December 2017

Circulating concentrations of free 17-hydroxycorticosteroids (17-OHCS) and "cortisol" and "corticosterone" were determined in rats, guinea pigs, and rabbits. (Quotation marks indicate that fluorescence present in plasma of these species has identical column chromatographic mobility of cortisol and corticosterone in human plasma.) In rats, "corticosterone" was present in greater amounts in adult than in young rats. Fluorescent material was also found in the "cortisol" fraction in both age groups but the 17-OHCS values were very low. In baby guinea pigs the fluorescent values for "cortisol" and "corticosterone" were about equal and were very high, as were the 17-OHCS values. During maturation all three values declined. In the younger age groups 17-OHCS values were two to three times greater than the "cortisol" values. In the two age groups of rabbits observed no 17-OHCS and only low "corticosterone" values were obtained. Instead, an unidentified, presumably steroidal, fluorescent material was found in the cortisol fraction.
Pulmonary and ductus arteriosus circulation in the fetal lamb before and after birth
Authors: Assali N. S. , Sehgal N. , Marable S.
Published: December 2017

Pulmonary and ductus arteriosus circulation was studied in lambs before and after delivery. Flows were measured with electromagnetic flowmeters and pulmonary and systemic pressures with strain gauges. Before interrupting the umbilical circulation and expanding the lungs, pulmonary artery pressure was higher than system pressure and the direction of flow in the ductus was from right to left. Flow in the pulmonary artery varied from 154 to 258 ml/kg/min, of which about 60% passed through the ductus and the remaining through the lungs. After cutting the umbilical cord and expanding the lungs, systemic pressure rose and pulmonary pressure fell. This reversed the direction of flow in the ductus. Pulmonary artery flow fell temporarily after cord occlusion but increased when respiration was established. Ductus flow decreased progressively until the end of the experiment. Total flow to the lungs increased by four- to sixfold after respiration had been established and the increase was due to reduction in pulmonary vascular resistance.
A study of renal phosphate excretion in the dog
Authors: Handler Joseph S.
Published: December 2017

Experiments were performed in 25 dogs in an attempt to demonstrate renal tubular secretion of inorganic phosphate. Clearances were obtained as plasma concentrations of phosphate were varied from normal to as high as 20 µm/ml. In addition, several manipulations were employed in various combinations with the presumption that they would facilitate the demonstration of secretion. The manipulations were the infusion of glucose, infusion of p-aminohippurate, administration of parathyroid extract, mannitol diuresis, loading with sodium phosphate intravenously for 3 days prior to study, and reduction of glomerular filtration rate. Despite the manipulations, no evidence of net secretion was obtained. The estimated filtered load of phosphate exceeded the rate of excretion of phosphate in every experiment. Furthermore, review of the literature indicates that secretion of phosphate in mammalian species has not been clearly established.
Renin content and excretory function of the kidney in rats with experimental hypertension
Authors: Brunner H. , Desaulles P. A. , Regoli D. , Gross F.
Published: December 2017

To determine relationship between kidney renin content and excretory function, rats with renal hypertension induced by unilateral clamping of the renal artery were given an oral load of 3 ml of 0.9% saline/100 g body wt. Excretion of the saline load was accelerated in rats with renal hypertension as well as in animals with hypertension due to overdosage with cortexone and salt, provided that the loading experiment was made 3–4 weeks after hypertension was established, but not when animals had been hypertensive for 11–14 weeks. Renin concentration was markedly reduced in the unclamped kidney and also in the kidney of the rats overdosed with cortexone and salt. Excreting capacity of the clamped kidney was compared with that of the unclamped kidney, after removal or after functional elimination of the contralateral kidney, by ligation of the ureter, 3, 24, and 48 hr after the operation. In all experiments excretion of saline load by the unclamped kidney was more rapid than by the clamped kidney, but the highest values were reached in the presence of a functional clamped kidney. Only in rats with elevated blood pressure was the load more rapidly excreted than in normal rats, but hypertension alone cannot be the only factor responsible, the excretion not being accelerated in unilaterally nephrectomized hypertensive rats. Although these hint at a connection between the renin concentration and renal function the nature of this relationship remains uncertain.
Effect of restraint on gastric acidity in the rat
Authors: Brodie David A. , Marshall Richard W. , Moreno Oscar M.
Published: December 2017

Chronic gastric fistula rats were prepared by implanting stainless steel cannulas in the rumen portion of the stomachs of male Holtzman rats and gastric content was collected in both the unrestrained and restrained state. Gastric secretion in acute pylorus-ligated rats, unrestrained and restrained, was studied at the same time. Volume of gastric content, free and total acidity, and free acid output were significantly lower in the chronic fistula rats as compared to the pylorus-ligated rats in the initial 4-hr collection period. A study of 24-hr gastric content in chronic fistula rats showed that restraint produced a significant decrease in volume, a significant increase in free and total acid concentration, and no change in free acid output, while the restrained pylorus-ligated rats had a significant decrease in volume, no change in free or total acid concentration, and a significant decrease in free acid output as compared with control values. This suggests that an increase in acid concentration is an important change produced in gastric secretion by restraint stress.
Induced renal vasomotion in the intact dog
Authors: Voudoukis Ignatios J. , Boucek Robert J.
Published: December 2017

X-ray viewing of the opacified artery at a preselected interval before and after the administration of a pressor substance permits the study of induced vascular motion. This technique applied to the renal arteries of the dog demonstrated their extreme sensitivity to the catecholamines. With certain of these drugs, the effect persisted even after the return of the blood pressure to the control level. Two types of renal vascular responses occurred. One was characterized by an apparent increased resistance in the arteries distal to the third division and followed the administration of short-duration pressor compounds. The second type of response, occurring after the use of long-acting pressor compounds, was more general affecting all sizes of arteries, the divisions of the renal arteries being extraordinarily sensitive. Spinal cord damage, producing paraplegia, apparently reduced the renal vascular tone as the runoff of the radiopaque substance into the kidney was enhanced. This improved the clarity of the arteriograms. The induced vasodilation of the paraplegic animal was returned to the control state by the administration of epinephrine or norepinephrine.
Force-velocity relations in mammalian heart muscle
Authors: Sonnenblick Edmund H.
Published: December 2017

Force-velocity relations were studied in the cat papillary muscle. As with skeletal muscle, a characteristic relation has been demonstrated between the velocity of shortening (V) and the force developed (Po). Two generalities have been shown to pertain. First, increasing initial muscle length increases the maximal developed force (Po) without a change in the maximal velocity of shortening (Vmax). Secondly, at any one muscle length, changes in frequency of contraction and chemical environment (increased calcium and norepinephrine) increase Vmax with a variable change in Po. Changes in Vmax thus help to characterize an inotropic intervention (altered contractility). Work and power, at any one muscle length, are functions of afterload, with maxima when the load is approximately 40% of isometric tension. With increasing initial muscle length, the work and power at any one afterload as well as the maximal work and power of the muscle are both increased. At constant initial length, positive inotropic interventions (increased frequency, increased calcium, and norepinephrine) increase the work at any one afterload as well as shift the maximal work potential to a higher afterload. Work performance thus depends on muscle length, the prevailing force-velocity curve, and the afterload at which the muscle is operating.
Relationship between blood pressure and organ weight in the rat
Authors: Fregly Melvin J.
Published: December 2017

A relationship exists between systolic blood pressure and the organ to body weight ratios of heart, thyroid, adrenals, and kidneys. In the cases of heart, thyroid, and adrenals, the relationship is sigmoid in character, with the fast-rising portion of the curve beginning at a systolic blood pressure range of 150–159 mm Hg. Beginning at this same blood pressure range, kidney weight ratio increases linearly with increases in blood pressure. It is of interest that these changes occur at a blood pressure range which is generally considered to lie either at the high range of normotension or the low range of hypertension. The only organ weight ratio apparently unrelated to systolic blood pressure level is that of the testis. Some interrelationships among weight ratios of these organs were observed and are discussed.
Transfer of carbon from formate to amino acids of milk protein in the intact cow
Authors: Black A. L. , Kleiber M. , Luick J. R. , Kaneko J. J.
Published: December 2017

C14-formate was injected intravenously into two lactating cows or infused into the cistern of a quarter of the udder in a third cow. Several amino acids were recovered from milk protein collected at intervals during a 36-hr period after the C14-formate was injected. The amino acids were assayed for C14 and, in the case of serine and methionine, degraded to establish the intramolecular C14 distribution. The C14 was found to be confined largely to the hydroxymethyl carbon of serine and to the methyl carbon of methionine. Relatively little C14 was present in other positions of these amino acids or in the other amino acids normally synthesized by the lactating cow, showing that formate carbon was confined to a very limited pool during utilization. The incorporation of formate carbon into amino acids apparently takes place largely outside the udder, presumably in the liver.
Passage of heterologous serum proteins from mother into fetal compartments in the rabbit
Authors: Kulangara Abraham C. , Schechtman A. M.
Published: December 2017

Dutch rabbits were injected with human or bovine serum albumin or human gamma globulin at 19, 24, and 28 days of gestation. Fetal serum, stomach contents, and exocoel, amniotic, and allantoic fluids were collected at intervals from 1 to 48 hr later and titrated with specific antisera. The presence of injected protein in fetal samples was confirmed by electrophoresis and absorption of rabbit protein, followed by the precipitin test. The three nonantibody proteins were detected in fetal serum and exocoel fluid after day 19 and in all fetal compartments after day 22, as soon as 1 hr after injection into the mother and after a maternal dose as low as 10 mg/kg., About 1 mg was found in the entire fetus 24 hr after a maternal dose of 62.5 mg/kg. The proteins passed from maternal circulation to uterine lumen, to exocoel, to allantois and amnion, and from amnion to stomach. They passed from mother to fetal circulation via the vessels of the yolk sac splanchnopleure and not through the allantoidean placenta.
Effect of hypertonic NaCl on cardiac arrhythmias
Authors: Nahas G. G. , Roebuck M. J. , Mark L. C.
Published: December 2017

Rapid CO2 washout with 100% oxygen after a period of severe hypercapnic acidosis produces in dogs a marked elevation of plasma K+ and ventricular fibrillation. The administration of 1.5 m NaCl to five dogs during CO2 washout prevented fibrillation, and all the animals survived. This procedure, which markedly diluted extracellular fluid, corrected hyperkalemia and prevented a fall in Na concentration. The plasma Na/K ratio, which dropped to 20 during acidosis, was restored to normal—42. In 15 additional animals, when the acidosis was corrected by intravenous administration of hypertonic THAM [tris(hydroxymethyl)aminomethane] or mannitol-glucose, asystole or arrhythmia occurred instead of fibrillation. The plasma Na concentration fell from 143 to 98 mEq/liter and the Na/K ratio was about 10 at asystole. A single injection of hypertonic NaCl, sufficient to raise Na levels above normal and thereby to increase the Na/K ratio despite an elevated K, produced resumption of systole. Similar results can be obtained with one-tenth the amount of calcium chloride.