bluuebunny/crossref_metadata_2025 huggingface dataset:
Alterations and mobilization of lipids in acute ethanol-treated rats
Authors: Elko E. E. , Wooles W. R. , Di Luzio N. R.
Published: December 2017

The hypothesis of augmented peripheral lipid mobilization as a factor in the development of the acute ethanol-induced fatty liver was evaluated. Rats received by oral intubation a single dose of either ethanol, isocaloric glucose, or sodium chloride and were killed 2–16 hr later. Indices of lipid mobilization were changes in the triglyceride content of epididymal fat depots and alterations in plasma free fatty acids (FFA). Acute ethanol-treated rats displayed a significant increase in hepatic triglycerides 4–16 hr after intubation. The body weight loss, plasma FFA, and depletion of triglyceride from epididymal fat pads were similar in all groups. Thus, by these parameters, acute ethanol intoxication does not enhance lipid mobilization.
Secretion by salivary glands deficient in acini
Authors: Schneyer C. A. , Schneyer L. H.
Published: December 2017

Rat submaxillary and parotid glands deficient in acini were obtained by selecting normal early postnatal animals or by ligating gland excretory ducts in adult animals. Acinar deficiency under these conditions was histologically confirmed for submaxillary and demonstrated for parotid glands. Glands with pronounced acinar deficiency secreted in response to pilocarpine. Flow rate, in the early postnatal state, approximated that from normal adult glands, whereas from ligated glands, flow was frequently reduced. In the two experimental conditions, potassium levels of the secretions from both glands were uniformly high (about 50 mEq/liter), approximating normal adult submaxillary levels. Sodium concentration was altered from normal only in parotid secretion of early postnatal animals where it was reduced, and in submaxillary secretion of ligated gland where it was elevated. These results, while not establishing the extent of secretory activity in the normal adult condition, demonstrate the capacity of ductal elements to secrete water, sodium, and potassium at rates frequently approaching those of normal adult glands.
Intestinal vascular permeability changes induced by radiation or nitrogen mustard
Authors: Sullivan Maurice F.
Published: December 2017

The appearance of an I131-labeled plasma protein substitute, polyvinylpyrrolidone (PVP), in the gastrointestinal tract was increased following X-irradiation or nitrogen mustard treatment of rats. Previous work suggests that leakage of PVP into the intestine may be used as an index of capillary permeability to large molecules. On this basis radiation and nitrogen mustard appear to act by a common mechanism on vascular permeability, as indicated by the similarity in the magnitude and duration of response to them. Partial-body irradiation showed that the upper small intestine was probably the principle site of leakage, and that the effect was caused by direct action on the intestinal epithelium. It was not caused by an increased excretion in the bile nor by an accumulation of secretions which were not reabsorbed because of impaired mucosal function. Treatment of X-irradiated animals with hesperidin-ascorbic acid, diisopropylfluorophosphate, or serotonin had no effect on PVP excretion but prophylactic administration of cysteine did decrease leakage.
Lipogenesis in adipose tissue of rats fed different diets
Authors: Khanade J. M. , Nath M. C.
Published: December 2017

Lipogenesis and glucose uptake by epididymal fat pads of rats fed different diets have been investigated. Lipogenesis was found to be depressed in rats fed high fat, high fat and high protein, thyroid, thiouracil, and thiamine-deficient diets. The same dose of insulin causes varying degrees of lipogenesis in the tissues, depending on the type of diet fed previously. Lipogenesis is above normal in hydrolyzed glucose-cycloacetoacetate-fed rats but glucose uptake is not appreciably affected. The glucose uptake of adipose tissue is significantly depressed in rats fed high fat, high fat with high protein, and vitamin B1 deficient diets, and in rats with hypothyroidism. Both hyperthyroidism and hydrolyzed glucose-cycloacetoacetate feeding increase glucose uptake by the tissue. Alloxan diabetes reduces lipogenesis as well as glucose uptake.
Adrenocorticosteroid hormones and manganese metabolism
Authors: Hughes Edwin R. , Cotzias George C.
Published: December 2017

An effect of two glucocorticosteroids on the transport of the essential trace element, manganese, is described. Mice receiving high doses of prednisolone or cortisol accumulated more radiomanganese in their carcasses and retained less in their livers than did untreated controls. In some respects this effect was similar to that seen when manganese salts were administered as significant metabolic loads. It was brought on regardless of whether the injected isotope was in the divalent ionic form or in the plasma-bound form. Treatment with mineralocorticosteroids alone did not affect manganese metabolism as tested here. Furthermore, Zn65 did not respond to the glucocorticoid effects exhibited by Mn54.
Direct adrenocortical stimulatory effect of serotonin
Authors: Verdesca Arthur S. , Westermann Coenraad D. , Crampton Richard S. , Black William C. , Nedeljkovic Relja I. , Hilton James G.
Published: December 2017

By means of direct arterial perfusion of the adrenal glands of the hypophysectomized dog, it was found that serotonin stimulated the secretion of hydrocortisone to a degree comparable to that seen during ACTH stimulation. Neither 5-hydroxytryptophan nor reserpine had this stimulatory effect. Physiologic mechanisms to explain the serotonin effect are discussed.
Regulation of amino acid activating enzymes of guinea pig tissues by androgens
Authors: Kochakian Charles D. , Tanaka Ryo , Hill John
Published: December 2017

Castration of adult male guinea pigs produced a gradual decrease in the specific activity of the amino acid activating enzymes (ATP-pyrophosphate 32 exchange) of the seminal vesicles to approximately 40% of the normal in about 40 days. The administration of testosterone, testosterone propionate, or androstan-17ß-ol, 3-one gradually restored the specific activity of the enzymes, but a higher dose of the androgen was needed than that required to restore the tissue weight. The enzyme activities of the prostate and temporal muscles were not altered by castration or androgen administration. The use of grouped or individual amino acids as substrate in the exchange reaction yielded the same pattern of responses as when a mixture of 17 amino acids was used as substrate.
Electrocardiogram and vectorcardiogram of Macaca mulatta in various postures
Authors: Hamlin Robert L. , Robinson F. R. , Smith C. Roger
Published: December 2017

Electrocardiograms and vectorcardiograms of 11 normal monkeys placed in dorsal-supine, right lateral, left lateral, and sitting positions were analyzed. Initial forces were directed cephalad, dextrad, and ventrad. Intermediate forces were directed caudad and slightly sinistrad, and either dorsad or ventrad. Terminal forces were directed cephalad, dextrad, and dorsad.
Action potential of amphibian single auricular muscle fiber: a dual response
Authors: Wright Ernest B. , Ogata M.
Published: December 2017

The intracellular recording of a single auricle fiber of frog or toad shows a spike-dip-plateau contour, suggesting two depolarizations are involved and two deflections comprise the action potential contour. Low oxygen reduces the plateau phase. Acetylcholine applied locally by microejection (or by vagal stimulation) acts specifically to cause plateau phase to be diminished or abolished and simultaneously affects the mechanical response in a like manner. The Q10 of the spike exposed alone by the acetylcholine effect is significantly different (1.2) from the Q10 value of the normal prolonged response (2.4) or the mechanogram (2.5). The evidence supports the idea that two ion carrier systems exist in the excitable membrane: one which reacts rapidly, the other more slowly. In cardiac muscle the fast one causes the spike depolarization, which itself is adequate to trigger the slow response. The slow system must react not specifically with potassium but with sodium also and causes the prolonged depolarization or plateau. Recovery is probably due to slow inactivation of this second process.
Blood pressure lowering action of adenosine diphosphate and related compounds
Authors: Gordon David B. , Hesse Donald H.
Published: December 2017

It was found upon intravenous injection of adenosine and its mono-, di-, and triphosphate in the rat that ADP produced the greatest fall in arterial blood pressure. At low dose levels ADP was about 147 times as potent as adenosine and about 45 times as potent as AMP or ATP on an equimolar basis. The rat is more sensitive to the blood pressure lowering action of the adenosine compounds than other species thus far tested.
Dynamic performance and stability of cerebral ischemic pressor response
Authors: Sagawa Kiichi , Taylor Aubrey E. , Guyton Arthur C.
Published: December 2017

A servoanalytic dynamic performance analysis of the cerebral ischemic pressor response has been made by the frequency response method applied to a linearized ischemic response system. Using an isolated perfused head preparation, the cerebral perfusion pressure was changed sinusoidally with a fixed amplitude of 5 mm Hg, but with varied periods ranging from 320 to 20 sec. The systemic arterial pressure waves caused by these input sinusoidal pressure waves were compared with the latter in terms of amplitude ratio and phase shift relationships. As the mean cerebral perfusion pressure was lowered toward zero, the response increased both in gain and phase lag. When these data were plotted as a vector locus on polar coordinates, the locus encircled the –1 point at 180° clockwise in 10 of 16 dogs. In two others, the locus approached very close to the –1 point. Thus, the nature of the cerebral ischemic pressor response was found to be unstable enough to go into self-oscillation under proper closed-loop conditions.
Innervation and reinnervation of cricothyroid muscle in the rabbit
Authors: Harreveld A. Van , Tachibana S.
Published: December 2017

The m. cricothyroideus of the rabbit is innervated by two motor nerves (n. laryngeus superior and n. laryngeus medius). No indication of extensive polyneuronal innervation was found in gold stained isolated muscle fibers and groups of fibers. Double end plates were found on about 2.5% of the fibers. It could not be ascertained whether they were supplied by different motor fibers or by branches of the same fiber. Intracellularly recorded spike potentials were observed in the same muscle fiber by stimulation of the two motor nerves in 6% of the fibers examined. The use of intracellular recording as a criterion for polyneuronal innervation was discussed. After resection of the n. laryngeus medius a fargoing reinnervation of the muscle by the n. laryngeus superior takes place.
Effect of hyperoxia, hypercapnia, and hypoxia on blood-cerebrospinal fluid barrier
Authors: Lending Miriam , Slobody Lawrence B. , Mestern Joan
Published: December 2017

Page 959: Miriam Lending, Lawrence B. Slobody, and Joan Mestern, "Effect of hyperoxia, hypercapnia, and hypoxia on blood-cerebrospinal fluid barrier." Line 3 from bottom of abstract should read: Hyperoxia alone did not cause significant changes.
Significance of sodium ions in active intestinal transport of nonelectrolytes
Authors: Csáky T. Z.
Published: December 2017

The active transport of 3-O-methylglucose, l-tyrosine, dl-phenylalanine, and uracil was studied in the surviving isolated frog small intestine suspended in Ringer's solution of varying ionic compositions. The rate of active transport of each nonelectrolyte was significantly reduced if Li or K was substituted for Na as the principal cation in the nutrient medium surrounding both surfaces of the intestine.
Histamine as a factor in tolerance to levarterenol
Authors: Coppola J. A. , Di Palma J. R.
Published: December 2017

Tolerance to levarterenol was developed in 18 dogs. It was observed that at the end of 3 hr the mean dose received by these animals was 13.3 µ/kg/min; initially, only a dose of 1–2 µ/kg/min was necessary to maintain an induced arterial pressure of 30–40 mm Hg above the normal. Using the fluorometric assay devised by Shore, the blood level of histamine was found to increase from an initial level of 47.8 ± 5.9 (se) µ/liter to a concentration of 89.6 ± 7.5 (se) µ/liter at the end of the 3-hr infusion of levarterenol. Levarterenol tolerance was also developed in animals whose histamine content had been previously depleted by 48/80. These dogs required an initial average dose of 3.97 µ/kg/min and a final average dose of 6.26 µ/kg/min. In another series of investigations, levarterenol was administered simultaneously with 48/80, and it was found that the dose of levarterenol was directly related to the blood level of histamine. The evidence indicates that levarterenol release histamine and that this release histamine exerts an influence on tolerance development to this pressor amine.
Absorption of bile salts from the small intestine in vivo
Authors: Weiner I. M. , Lack Leon
Published: December 2017

The absorption of bile salts from the small intestine of the guinea pig was studied in vivo by determining the biliary excretion of bile salts injected into isolated regions of the small bowel Taurocholate, glycocholate, and cholate appeared in bile in significant amounts only when they were introduced into the distal part of the small intestine (ileum), indicating that there is little, if any, absorption by diffusion through the proximal mucosa. Allowing animals to eat a relatively high fat diet before the experiments did not alter the pattern of intestinal absorption of bile salts. The results confirm previous in vitro studies on the active transport of bile salts by the ileum.
In vivo transport of calcium from healed Thiry-Vella fistulas in dogs
Authors: Cramer Carl F. , Dueck John
Published: December 2017

Calcium transport was studied in vivo in dogs by perfusing solutions of various calcium concentrations through healed jejunal Thiry-Vella fistulas. The method is simple, quantitative, and it avoids a number of difficulties of interpretation inherent in tracer and in vitro studies. At quite low concentrations the rate of Ca absorption was approximately proportional to Ca concentration, but at higher concentration the rate fell off continuously. Above 12.5 mm/liter the absorption rate remained constant at approximately 0.5 mm/hr. There was some variation from week to week in the same dog and between different dogs. However, in 30 runs on 10 dogs this maximum absorption rate averaged 18.5 ± 1.1 mg Ca/hr. Simultaneous administration of magnesium depressed maximum Ca absorption of 9.3 mg Ca/hr. The calcium absorption data conformed to the Michaelis-Menten equation. The approach to a maximal absorption rate with increasing Ca concentration, the Mg competition, and the conformity to the Michaelis-Menten kinetics all suggest that Ca is absorbed by a carrier system which may involve either active or facilitated transport. The method lends itself to studies of physiological factors which may affect calcium absorption.
Amino group requirement for in vitro intestinal transport of amino acids
Authors: Spencer Richard P. , Bow Ted M. , Markulis Mary Anne
Published: December 2017

The amino group requirement for transintestinal transport of amino acids against a concentration gradient was investigated using hamster everted intestinal sacs. Although glycine (5 x 10–3 m) was transported against a concentration gradient, acetic acid was not. Similarly, l-phenylalanine was transported, whereas phenylpyruvic acid, phenylpropionic acid, phenyllactic acid, and cinnamic acid were not. l-Tryptophan was transported, but indolyllactic acid was not. The amino group was thus essential for transport by this system. n-Methylglycine and l-proline were accumulated from mucosa to serosa against a concentration gradient. Hence, one hydrogen of the amino group can be replaced. However, n-phenylglycine was not accumulated across these preparations, suggesting that the moiety replacing the amino hydrogen can not be sterically bulky. α-l-Alanine was transported against a concentration gradient from mucosa to serosa, but ß-alanine was not. This is in contrast to other systems which accumulate ß-alanine against a concentration gradient. Anthranilic acid, with the amino group in a relative ß position, was also not accumulated across everted intestinal sacs.
Removal of decapacitation factor from seminal plasma by high-speed centrifugation
Authors: Bedford J. M. , Chang M. C.
Published: December 2017

The fertilizing ability of capacitated rabbit sperm is inhibited by mixing with seminal plasma; this is termed "decapacitation." The decapacitation factor was not destroyed or removed by freezing, heating to 65 C, or by prolonged dialysis, and was retained in the precipitate produced by the treatment of seminal plasma with 100% ethanol at –30 C. However, following centrifugation of seminal plasma for 3 hr or more at 105,000 g, the decapacitation activity disappeared. The disappearance of activity was not due to denaturation. Using spectrophotometry and moving boundary electrophoresis, no change could be detected in the protein components of the supernatants to account for the change in biological activity. It is concluded that the decapacitation effect of seminal plasma is related to a discrete molecule of large size. This may be protein, or conjugated with protein of a relatively heat-stable nature, which interacts with the active surface of the capacitated sperm head.
Localization of central cardiovascular control mechanism in lower brain stem of the cat
Authors: Chai C. Y. , Wang S. C.
Published: December 2017

The lower brain stems of 42 vagotomized, midcollicular decerebrate cats under chloralose anesthesia were explored for vasomotor and cardiac responses by means of the stereotaxic technique. When a stimulus was given through bipolar coaxial electrodes with minute exposures at the tips, it was found possible to localize these responses in very discrete areas in the dorsal reticular formation and the adjacent periventricular gray. With current of slightly higher intensity, comparable responses could also be obtained in the ventrolateral reticular formation. It is suggested that the latter constitutes the hypothalamic efferent pathways, while responses from the dorsal medulla signal the activation of the bulbar pressor and cardioaccelerator mechanism. Further, pressor responses from the medulla on the right side are very often accompanied by marked cardioacceleration and only slight or moderate augmentation of cardiac contractions, whereas those from the left are accompanied by marked augmentation and moderate cardioacceleration. This finding suggests that the medullary sympathetic system descends predominately in the spinal cord of the homolateral side.
Central control of sympathetic cardioacceleration in medulla oblongata of the cat
Authors: Wang S. C. , Chai C. Y.
Published: December 2017

Under chloralose, as well as under pentobarbital anesthesia, stimulation of the dorsal medulla elicited after decerebration a cardioacceleration comparable to that before decerebration. Similar increases in the heart rate were also obtained after additional ablation of the remaining midbrain and portion of the pons. In addition, it is possible in these decerebrate animals to elicit cardioaccelerator reflexes by occluding the common carotid arteries or by stimulating the central end of the sciatic nerve. Our findings are contrary to those reported by Peiss ( J. Physiol., London 151: 225, 1960) and do not support his contention that the dorsal medulla constitutes only an afferent cardioaccelerator pathway to the hypothalamus. Our results support the concept that an important integrative mechanism for cardioacceleration, as well as for vasomotor reaction, resides in the dorsal medulla, and that higher neural structures such as the hypothalamus serve a regulatory function.
Depolarizing-electrode monophasic curves and myocardial infarction ST shift
Authors: Dower Gordon E. , Ziegler William G. , Geddes Margaret A. , Osborne John A.
Published: December 2017

The in vivo monophasic curves of the potential variations between an intracellular microelectrode and a remote reference electrode show irregular upstrokes. These can be removed by subtracting from them the ECG recorded from a wire loop surrounding the microelectrode. Since similar irregularities are present in the upstrokes of monophasic curves obtained from potassium-ion depolarizing electrodes, the effect of a similar subtraction technique was tried. Again, sigmoid upstrokes were obtained. The role of the potassium ion is to render the membrane inexcitable at the electrode. The result is that the electrode follows the potential changes of the cell interior with a lag determined by a time constant due to the membrane resistance and the capacitance of the electrode to the rest of the animal. Since the ST changes in myocardial infarction can be considered low amplitude monophasic patterns superimposed on the ECG, and it has been found that the release of potassium from damaged muscle can produce monophasic patterns, it now seems possible to present a satisfactory explanation of such changes.
Recovery of cerebral cortex from asphyxiation
Authors: Harreveld A. Van , Tachibana S.
Published: December 2017

Cerebral asphyxiation causes, after a latency of 2–3 min, a marked increase in cortical impedance, a transport of chloride (probably accompanied by sodium) into apical dendrites and a swelling of these structures. The reversibility of these changes was investigated by reoxygenating the brain for 15 min after periods of asphyxiation ranging from 15 to 75 min. All the asphyxial changes were in part of the experiments completely reversed by reoxygenation after circulatory arrests up to 60 min in duration. The course of the impedance changes showed this active removal to occur during the first 5–10 min of reoxygenation. Even after asphyxiations of long duration electrolytes can thus be removed actively from cellular elements. In part of the experiments abnormal amounts of chloride were found after reoxygenation in the apical dendrites although the cortical impedance and the dendritic diameter had reverted to preasphyxial values, indicating that in these experiments sodium had been removed in combination with an anion other than chloride.
Renal hypertrophy and function in irradiated and nephrectomized rats fed a high protein diet
Authors: Konishi Frank , Brauer R. W.
Published: December 2017

Male rats exposed to a total of 740 rad X-irradiation were fed a high protein diet and unilaterally nephrectomized to investigate functional and compensatory regenerative capacity of the kidney as probable indices of residual radiation injury. The extent of compensatory hypertrophy after nephrectomy showed a significantly greater increase due to the high protein diet but no effect due to irradiation. Estimates of maximal tubular excretions of p-aminohippurate (PAH), however, were significantly greater in irradiated groups than in control groups when determined 3 weeks postnephrectomy. Renal clearances of CIn and CPAH were significantly depressed after nephrectomy but not after radiation. Histological studies of the kidneys did not indicate renal damage by radiation except for an isolated instance of a renal neoplasm in an irradiated, nephrectomized rat fed a high protein diet. The results indicate that radiation does not modify compensatory hypertrophy after unilateral nephrectomy but appears to increase the apparent functional capacity of the tubules.
Adrenal medullary and adrenal cortical response to stimulation of diencephalon
Authors: Goldfien Alan , Ganong William F.
Published: December 2017

Epinephrine and norepinephrine secretions were measured before, during, and after electrical stimulation of 66 points in the hypothalamus and adjacent parts of the brain in 19 dogs anesthetized with pentobarbital. The 17-hydroxycorticoid response to stimulation of 21 points in 11 dogs was also measured. Catecholamines increased with I–V stimulation of 18 points in the region of the dorsomedial and posterior nuclei of the hypothalamus and in a band extending laterally, inferiorly, and caudally from them. Blood pressure rose during the stimulation of one of these points, fell during stimulation of six, and was unchanged during stimulation of eight. Catecholamine secretion increased during stimulation of 12 of 19 points stimulated at 3–10 v. Selective increases in norepinephrine secretion were not observed. Output of 17-hydroxycorticoids increased without a change in catecholamine secretion when 4 points in the ventral hypothalamus and orbital frontal lobe were stimulated. Increased adrenal medullary secretion was not associated with increased adrenocortical secretion.
Relationship of blood flow to pressure in the intestinal vascular bed of the dog
Authors: Texter E. Clinton , Merrill Steven , Schwartz Melvin , Derstappen Guido Van , Haddy Francis J.
Published: December 2017

The relationship of pressure in the superior mesenteric artery, mesenteric small artery, mesenteric small vein, and portal vein to the rate of blood flow in the superior mesenteric artery was studied in eight dogs. Total bed resistance to blood flow decreased as a function of flow over the range 20–60 ml/min but increased as a function of flow over the range 90–270 ml/min. The onset and cessation of the resistance increase were associated with pressures in the superior mesenteric artery of 64 and 205 mm Hg, respectively. These resistance changes resulted mainly from change of resistance to flow through vessels less than 0.5 mm diameter. The findings suggest that the intestinal vascular bed, like the renal vascular bed, has a local mechanism which antagonizes changes of flow rate produced by variation of arterial pressure.
Hepatic production of serum alpha2 and beta globulins in rats after injury
Authors: Neuhaus Otto W. , Balegno Hector F. , Milauskas Albert T.
Published: December 2017

Changes produced in the distribution of serum glycoproteins in rats following partial hepatectomy and chemical hepatic necrosis were studied, using paper electrophoresis. Elevations in concentrations of the α2 and ß-globulins usually resulting from injury were abolished by partial hepatectomy. Chemical hepatic necrosis, carbon tetrachloride, reduced the control level of the α2 globulins in serum but did not abolish the response usually elicited by sponge implantation. The concentration of ß-globulins was elevated by treatment with carbon tetrachloride. Subsequent trauma by sponge implantation caused a further increase in these proteins. It is concluded that the liver is a major site of synthesis of the α2 and ß-globulins which are produced in response to trauma.
Uptake of lactate and pyruvate by intact kidney of the dog
Authors: Levy Matthew N.
Published: December 2017

In dogs anesthetized with pentobarbital, mean renal blood flow was 312 ml/min/100 g kidney wt., and mean renal O2 consumption was 6.46 ml/min/100 g. Under control conditions mean net uptake of lactate was 20.7 µM/min/100 g. The precise metabolic fate of lactate could not be ascertained from these studies. If it were completely oxidized, it would account for 21.6% of the total O2 consumption. When blood lactate levels were raised by infusion of L(+)lactate, there was a progressive increase in rate of uptake. Under control conditions, the net handling of pyruvate delivered to the kidney was negligible. When blood levels were elevated by pyruvate infusions, there was significant net uptake; when pyruvate levels increased as the result of lactate infusions, there was no augmentation of net uptake. Similarly, elevated levels of lactate occurring during pyruvate infusions did not elicit significant acceleration of lactate uptake. When renal blood flow was acutely reduced, renal extraction of oxygen, lactate, and pyruvate remained remarkably constant. Thus, a decrease in net uptake of oxygen and lactate was proportional to the rate of blood flow, and pyruvate uptake was negligible over the entire range of blood flows.
Reserpine and adrenocortical function in chickens
Authors: Newcomer W. S.
Published: December 2017

Single injections of reserpine into young cockerels produced an increased concentration of free Δ4-3-keto-corticosteroids (particularly corticosterone) in both the adrenal glands and plasma in 3 hr; the increase subsided thereafter. Single injections of reserpine, promazine, or serotonin produced an acidophilia within 6 hr.
Insulin stimulus of leucine incorporation in rat liver protein
Authors: Penhos J. C. , Krahl M. E.
Published: December 2017

Slices were prepared from livers of partially pancreatectomized rats and incubated 2 hr in Krebs bicarbonate solution at 37 C. Incorporation of leucine-1-C14 into protein decreased progressively as severity of diabetes increased during 1–6 months after operation; at 2–4 months insulin (0.01 U/ml of medium) plus glucose (200 mg/100 ml) added in vitro stimulated incorporation 62–78%; stimulation was not significant at 6 months. Neither insulin nor glucose was effective separately. Alkali-inactivated insulin was ineffective, even with glucose. Liver slices from sham-operated rats responded similarly to insulin under the present experimental conditions, although the maximum percentage stimulation was smaller than in the partially pancreatectomized series. It is concluded that insulin can act directly on the liver to stimulate amino acid incorporation in protein by a mechanism dependent on the presence of glucose.
Uptake and metabolism of amino acids by the dog liver perfused in situ
Authors: McMenamy Rapier H. , Shoemaker William C. , Richmond Jonas E. , Elwyn David
Published: December 2017

Dog livers were perfused in situ for periods up to 6 hr with dog blood recycled through a pump-oxygenator. An amino acid mixture was administered for 90 min. Concentrations of amino acids were determined at intervals of 30 min or more. Rates of uptake and metabolism were calculated. After the start of perfusion, there is a fall in most plasma amino acid concentrations and a reciprocal rise in liver amino acids. Addition of amino acids causes a sharp rise in plasma amino acids. There is a rapid uptake of most of the amino acids by liver, although the concentrations of amino acids in liver fail to rise appreciably. Notable exceptions are valine, leucine, and isoleucine. Uptake of amino acids stimulates: a) an increase in the rate of synthesis of urea which ultimately accounts for 90% of the metabolized amino acids; b) a net synthesis of ornithine; and c) net noncatabolic metabolism of amino acids which may in part be protein synthesis. The results support the view that the liver temporarily stores a part of ingested amino acids as proteins, and subsequently makes them available to other organs.
Effects of acetazolamide and metabolic acidosis and alkalosis upon gastric acid secretion
Authors: Byers Frank M. , Jordan Paul H. , Maren Thomas H.
Published: December 2017

The gastric H+ secretory responses to i.v. HCl, NaHCO3, and acetazolamide were studied in Heidenhain-pouch dogs that had been stimulated to secrete by feeding. Acetazolamide in low doses (5 mg/kg) gave a 65% reduction in H+ output for 2–4 hr, after which H+ secretion increased above normal, coincident with renal HCO3– loss and metabolic acidosis. Higher doses produced a greater systemic acidosis and resulted in less initial reduction of H+ and greater augmentation. Doses of 75–100 mg/kg, given 17 hr before feeding to produce a systemic acidosis, resulted in increased secretion, even though sufficient drug remained in the plasma to inhibit tissue carbonic anhydrase. Metabolic acidosis (i.v. HCl) initially suppressed but later augmented gastric H+. Acetazolamide had no suppressive effect in the presence of either an HCl- or acetazolamide-induced acidosis. Metabolic alkalosis (i.v. NaHCO3) reduced gastric H+ in regular feeding experiments and in dogs made acidotic by acetazolamide.
Microelectrode study of accessory optic tract in the rabbit
Authors: Hamasaki Duco , Marg Elwin
Published: December 2017

Microelectrodes were used to study the physiological properties of single units from the posterior accessory optic tract-transpeduncular tract in the rabbit. Both on and on-off elements were isolated in the nucleus of the transpeduncular tract. Only one off element was isolated. Intermittent photic stimulation was found to evoke a unique sequence of responses from the accessory optic system. The units gave a good response to the low rates of stimulation, decreased or stopped firing at the intermediate rates, and resumed firing at still higher rates of stimulation. The nucleus of the transpeduncular tract was found to receive its activation from elements in the central part of the retina. Recordings from elements of the nucleus of the posterior accessory optic tract showed that their physiological properties were very similar to those of the nucleus of the transpeduncular tract.
Hypertension induced in rats by small doses of cadmium
Authors: Schroeder Henry A. , Vinton William H.
Published: December 2017

Female rats on a cadmium-free diet exhibited fluctuating systolic hypertension when given cadmium in drinking water at subtoxic levels (5 ppm) from the time of weaning for 180–240 days. Relatively small accumulations of cadmium in kidney and liver were present, and hypertension was the only sign of toxicity. Male rats failed to show more than a tendency to hypertension when treated similarly. When rats were given choices of sodium chloride in drinking water, females took more water and two to three times as much salt as did males. Animals exposed to sodium chloride drank more water than did those not exposed, whether given cadmium or not. The presence of cadmium and/or hypertension at these concentrations did not affect the intake of salt or water.
Quantitative studies of protein and water shifts during inflammation
Authors: Aschheim Emil , Zweifach B. W.
Published: December 2017

A study was made of the dose-response relationship after injury induced by histamine, an antigen-antibody reaction, and serotonin. The intensity of the inflammatory reaction, as measured by the local clearance of albumin-I131, was found within a certain range to be related to the logarithm of the dose. The relative movements of water and protein were studied by comparing the water increment calculated on the basis of radioactive protein accumulation with the actual increment in the water content of the tissue. At threshold doses of histamine and at the beginning of xylene inflammation, the skin gains more water than protein. Subsequent to this stage and at higher histamine doses, protein is transiently retained by the inflamed skin. After these changes, the ratio of the increments of tissue water and protein approaches that of plasma. Possible mechanisms responsible for these phenomena are examined.
Effect of strophanthidin on electrolyte content and PAH accumulation of rabbit kidney slices
Authors: Burg Maurice B. , Orloff Jack
Published: December 2017

The cardiac aglycone strophanthidin interferes with cation transport and p-aminohippurate (PAH) accumulation in slices of rabbit renal cortex. Incubation of cortical slices with 3 x 10–5 m strophanthidin results in a depression in slice potassium content, an increase in slice sodium content, and a decrease in the slice to medium ratio for PAH without significantly affecting oxygen consumption. These effects are prevented by increasing the concentration of potassium in the bathing medium. The interference with PAH accumulation is apparently secondary to the associated potassium depletion and does not represent a specific effect of the cardiotonic steroid on PAH transport. No evidence for mineralocorticoid antagonism of the aglycone effect was obtained. The former compounds exert no effects on either the electrolyte composition or PAH accumulation of cortical slices nor do they prevent the response to added strophanthidin.
Effect of progesterone on plasma luteinizing hormone activity
Authors: McCann S. M.
Published: December 2017

The luteinizing hormone (LH) activity of ovariectomized rat plasma was estimated by the ovarian ascorbic acid depletion technique. A single subcutaneous injection of 25 mg of progesterone produced a slight decrease in this LH activity which was first demonstrable 2 days after injection of progesterone. If a second injection of 25 mg of progesterone was given 2 days after the first, a marked decrease in LH activity was found on testing a day later. Three daily subcutaneous injections of 5 mg of progesterone failed to significantly depress the LH activity in ovariectomized rat plasma. Pretreatment of these ovariectomized rats with estradiol benzoate rendered them more sensitive to the effects of progesterone in that 4 mg progesterone/day was then able to significantly depress the LH activity in their plasma. It was concluded that progesterone alone has a feeble inhibitory effect on the secretion of LH but that estrogen pretreatment sensitizes the animal to this inhibitory action of progesterone.
Hypoxia and reproduction in Swiss mice
Authors: Baird Bernard , Cook S. F.
Published: December 2017

Swiss albino mice were maintained in closed decompression chambers: 1) continuously at simulated altitudes of 14,200 and 18,000 ft; 2) intermittently, 6 hr/day, at 20,000, 21,500, and 25,000 ft; 3) continuously at sea level with atmosphere of 12% oxygen, 88% nitrogen. All animals were acclimatized before exposure. In all cases mating behavior was normal, and there was no functional impairment of male fertility. Impregnation was observed with all mated, adapted females in almost all experiments. Exceptions were considered due to early resorption of embryos. No significant effect of hypoxia was noted on implantation, placentas, vascularization, gestation time, or parturition. Adverse effects of hypoxia were manifested primarily in resorption of fetuses when they had attained a critical size (about 7 mm). The incidence of resorption correlated directly with stress level, expressed as duration and intensity of hypoxia, and is considered to be contingent on the critically respiring mass of fetal tissue.
Coronary vasomotor tonus in atherosclerotic dogs
Authors: Cross Cecil E. , Oblath Robert W.
Published: December 2017

The atherogenic regimen imposed upon the animals studied here resulted in several distinct abnormalities of the coronary circulation. The structure of the coronary arteries was modified by extensive atheromatous deposits. During control states before the administration of vasoactive drugs, coronary flow per unit of net propulsive force and heart weight was unvaried or increased. The ability of the atheromatous coronary tree to increase or decrease its vasomotor tonus was markedly curtailed. The abnormalities mentioned here were proportional with the severity of the atherogenic regimen.
Mechanical properties of the living dog aorta
Authors: Evans Robert L. , Bernstein Eugene F. , Johnson Evelyn , Reller Carl
Published: December 2017

The variation of living dog aortic cross sections with volemic pressure changes is given for states before and after thoracotomy. The relationship of vessel cross section to pressure is approximately linear, does not follow Hooke's law, and is roughly the same for both dynamic and relatively static changes. The implied and directly measured propagation velocities are comparable to each other.
Postextrasystolic potentiation in the isolated rat heart
Authors: Meijler F. L. , Bogaard F. v. d. , Tweel L. H. v. d. , Durrer D.
Published: December 2017

"Postextrasystolic potentiation" of isotonic contractions of the intact isolated rat heart was studied. It was found that the Frank-Starling mechanism does not participate in the increase of the contraction following a premature beat and a compensatory pause. A linear relationship could be demonstrated between the prematurity of the extra beat and the amplitude of the postcompensatory contraction. The increase of amplitude of the postcompensatory contraction was found to counterbalance the decrease of the premature beat. At a constant net rate, whether the rhythm was regular or not, the average contraction height was constant. Postextrasystolic potentiation pattern following an interpolating premature beat was different from postextrasystolic potentiation following a premature beat and a compensatory pause. Postextrasystolic potentiation following an interpolating premature beat could not be distinguished from poststimulation potentiation. It was therefore concluded that postextrasystolic potentiation does not exist as a specific phenomenon.
Staircase, rest contractions, and potentiation in the isolated rat heart
Authors: Meijler F. L.
Published: December 2017

Variation in amplitude of isotonic contractions of intact isolated rat hearts, following changes in cycle length, were studied. It was found that a staircase-like phenomenon resembling the original Bowditch effect cannot be evoked in a intact mammalian heart without special measures, such as adding acetylcholine to the perfusion fluid. A steady state relation of rate to amplitude of isotonic contractions was demonstrated. Potentiation of contractility can be originated by sudden changes in stimulation rate. A rest period preceding the changes in stimulation rate does not change the potentiation found originally. At a constant rate the amplitude of a contraction is determined by the preceding cycle length. This relation has been called restitution. Theoretical evidence is presented in an attempt to demonstrate that restitution and potentiation are due to the same process. It can be concluded that Bowditch's staircase does not play a role in the relationship between cycle length and contractility in intact hearts and the statement that restitution and potentiation are due to the same process offers an opportunity to describe all effects of changes in cycle length on isotonic contractions as one phenomenon.
Calcium effect on performance of the heart
Authors: Feinberg H. , Boyd E. , Katz L. N.
Published: December 2017

Calcium, as the 10% gluconate, was rapidly infused into the venous circulation of the dog "coronary flow" preparation. It was also infused into the aortic circulation perfusing the heart of the "isovolumic" preparation, in which an otherwise empty, beating left ventricle was filled with a known volume of fluid contained within a slack latex balloon. In the coronary flow preparation, calcium was found to: a) increase heart rate, b) leave aortic blood pressure unchanged, c) increase the velocity of the left ventricular pressure rise, d) decrease the circumference of the left ventricle, and e) increase the coronary flow and myocardial oxygen consumption per beat in relation to the existing mean aortic pressure. In the isovolumic preparation calcium increased the peak ventricular pressure at a given balloon volume, but had no effect on the ratio relating myocardial O2 consumption to heart rate and left ventricular pressure developed. In both preparations O2 extraction was decreased. In addition, indirect evidence for the Fenn effect in the contraction of the intact heart is presented.
Effects of angiotensin on pulmonary and systemic hemodynamics
Authors: Chimoskey John E. , Blaquier Pedro C. , Taquini A. C. , Bohr David F.
Published: December 2017

In ten morphine-urethan anesthetized dogs single injections of 2.0 µg/kg of synthetic valine 5 angiotensin II amide elevated systemic and pulmonary arterial pressures and depressed heart rate. Thirty-minute intravenous infusions of angiotensin (0.4 and 1.0 µg/kg/min) in eight dogs elevated systemic arterial pressure and diminished heart rate. Pulmonary arterial, pulmonary wedge, left ventricular end-diastolic, and right atrial pressures were all slightly elevated; mean cardiac output did not change. Calculated total pulmonary resistance and pulmonary arterial resistance were diminished; central blood volume was elevated. These findings suggest that elevated systemic pressure and resistance increase myocardial work and induce reflex bradycardia, thereby elevating left ventricular end-diastolic, pulmonary wedge, and pulmonary arterial pressures. Systemic vasoconstriction also contributes to the elevated right atrial pressure and distention of the pulmonary vascular bed, which diminishes total pulmonary and pulmonary arterial resistance. These findings are not incompatible with the theory that the renin-angiotensin system is active in essential hypertension.
Sodium, potassium, chloride, and water in frog gastric mucosa
Authors: Davenport Horace W. , Alzamora Fernando
Published: December 2017

In fresh mucosas Na is 45–52, K 52–60, and Cl 39–41 mEq/kg. In mucosas incubated 4 hr at 25 C in salt solution, equilibrium volume of radio-iodinated serum albumin (RISA) is 231 ± 7 ml/kg. Other volumes are: inulin 383 ± 14, mannitol 515 ± 22, arabinose 550 ± 22. During incubation with or without 0.1 mm histamine, mucosal Na remains constant at 72 ± 2, K rises from 51 ± 1 to 63 ± 1, and Cl falls from 50 ± 3 to 32 ± 4 mEq/kg. With 0.1 mm 2,4-dinitrophenol, Na and Cl rise while K falls. When [Na]0 is constant, mucosal Na remains constant, but K and Cl are direct linear functions of [K]0 and [Cl]0. When [K]0 replaces [Na]0 mole for mole, mucosal Na falls and K rises. Mucosas stripped of surface epithelial cells have the following volumes: RISA 336 ± 13, inulin 500 ± 23, arabinose 629 ± 38 ml/kg. On incubation Na and K are approximately constant, but Cl falls.
Differential changes in permeability of mesentery to rubidium and phosphate
Authors: Berndt W. O. , Gosselin R. E.
Published: December 2017

The transfer of Rb86 cations and of P32-orthophosphate anions across isolated rabbit mesentery exhibited kinetic patterns that are usually associated with passive diffusion. Because loading with unlabeled phosphate did not reduce the P32 flux, one infers that no carrier mechanism was operative in this transfer, in accordance with prior conclusions about Rb86. An elevation of temperature from 28 to 38 C speeded the transport of both substances, but the effect on the P32 flux was significantly greater (Q10 = 2.1 for P32, 1.6 for Rb86). Similarly, the addition of atropine promoted the contemporaneous movements of both tracers, with the P32 flux showing a significantly greater rise. The effect of atropine was blocked by prior treatment of the membrane with acetylcholine, but acetylcholine alone was generally inactive. Histamine and 5-hydroxytryptamine produced a distinctive response; both increased the Rb86 flux without affecting the migration of P32. These drug and temperature effects could not be duplicated with cellulose membranes. The results are discussed in relation to pinocytosis and to diffusion through pores as possible modes of transport, but no adequate explanation of mechanisms is yet available.
Relative roles of glomerular filtration and tubular reabsorption in denervation diuresis
Authors: Blake William D.
Published: December 2017

Experiments have been carried out on anesthetized, laparotomized dogs in which urine samples were collected from both kidneys after acute denervation of one. Renal functions were estimated by standard procedures with creatinine clearance (CCr) as an index of glomerular filtration rate. Urine flow and solute excretion were greater from the denervated kidney (D) than from the innervated kidney (I) under all conditions of solute diuresis. The magnitude of denervation diuresis, D/I for urine flow, was directly related to the relative excess of electrolyte excretion on the denervated side, D/I for electrolyte excretion rate. D/I for electrolyte excretion was not correlated with D/I for CCr and remained above 100% in all experiments despite a fall of D/I for CCr below 100% in 10 of 30 comparisons. Since excessive electrolyte excretion by the denervated kidney could not be explained by greater total filtration rate, it was reaffirmed that denervation caused a defect in proximal tubular reabsorption of sodium, either by decreased reabsorptive activity of all tubules or by redistribution of filtration toward tubules of lesser reabsorptive capacity.