bluuebunny/crossref_metadata_2025 huggingface dataset:
Ovarian hormones and resting potential of rabbit uterine smooth muscle
Authors: Kao C. Y. , Nishiyama A.
Published: December 2017

Myometrial strips isolated from uterus of rabbits under either estrogen or progesterone domination were impaled with glass capillary microelectrodes for measurement of resting potential. This was found to be 49.81 ± 0.34 mv for estrogen-dominated myometrium (mean ±se of 616 samples), and 48.86 ± 0.43 mv for progesterone-dominated myometrium (514 samples), the difference between the resting potentials being insignificant. Therefore, the validity of the so-called "progesterone-block" hypothesis is questioned. Collagen was present in 14 g/kg of wet tissue in both hormonal states. These amounts did not hold sufficient chloride to appreciably lower the intracellular chloride concentrations, which were high enough to suggest either a complex distribution pattern or some active uptake for chloride. The relative cation permeabilities (Pna/Pk) were estimated as 0.11 for the estrogen-dominated myometrium, and 0.17 for the progesterone-dominated myometrium.
Ca45 uptake and tissue calcium in K-induced phasic and tonic contraction in taenia coli
Authors: Urakawa N. , Holland W. C.
Published: December 2017

High-K medium produces a tonic contraction in guinea pig taenia coli. If muscle strips are preincubated in glucose-free medium, K produces only a phasic contraction. A comparison of Ca45 entry and tissue Ca changes in the two responses were made. Both responses are accompanied by an enhanced uptake of Ca45. In addition to an increased Ca45 uptake, a significant rise of tissue Ca was observed during the tonic contraction. No detectable changes in tissue Ca were noted in the phasic contraction. In light of modern theories of muscle contraction, it was proposed that in the phasic contraction, sufficient Ca is released from a cellular site to initiate contraction, whereas in the tonic contraction enough Ca crosses the membrane to initiate contraction. The transmembrane Ca transport involved in the latter response appeared to be dependent on metabolism.
Effect of correction of catheter distortion on calculated liver sinusoidal volumes
Authors: Goresky Carl A. , Silverman Melvin
Published: December 2017

The use of a collecting system to obtain samples in the multiple indicator-dilution technique produces delay in and distortion of the dilution curves. A method for removing these is described and the method is applied, using an analog computer, to previously published hepatic venous dilution curves ( Am. J. Physiol. 204: 626, 1963). This correction increases with the rate of change of concentration and so is greatest for the labeled red cell dilution curves. The effect of the distortion on the previously described linear method for determining liver sinusoidal and extravascular volumes is described. Extravascular volumes of distribution of rapidly diffusible, completely recovered indicators (equivalent to transit-time volumes) are found to be unaffected, whereas catheter distortion is found, with the system used, to produce an increase in estimated sinusoidal blood volume of an average magnitude of 15%. These results suggest that the value obtained after removal of distortion of the collecting system is still in error by some amount of approximately the same order of magnitude because of the effect of portal and hepatic veins.
Specificity of mammalian kallidinogen
Authors: Fasciolo J. C. , Halvorsen K.
Published: December 2017

Hog pancreas kallikrein does not cause a blood pressure drop in the rat, but lowers the blood pressure in the dog. Since this lack of effect could be due to the inability of hog pancreas kallikrein to act upon rat plasma, the in vitro release of kallidin with the plasma of different species was studied. Human, dog, swine, rat, guinea pig, and ox plasmas were incubated for different periods of time with hog pancreas kallikrein, and the bradykininogen (kallidinogen) consumed and the kallidin released were measured. It was found that hog pancreas kallikrein does not release any kallidin with rat and guinea pig plasma; it releases small amounts with pig plasma and greater amounts with bovine, dog, and human plasma. The bradykininogen consumption showed the same sequence.
Absence of conduction of spreading depression through cortical region damaged by asphyxiation
Authors: Hull C. D. , Harreveld A. Van
Published: December 2017

An area of cerebral cortex was asphyxiated for 30–35 min by application of a weight exerting a pressure on the tissue greater than the blood pressure. Three days later the asphyxiated region showed in most experiments a marked loss of nerve cells. The glia seemed to be better preserved. Spreading depression could not be made to pass through the area when asphyxiation had caused substantial neuronal destruction. These observations do not support a possible involvement of the glia in the propagation of spreading depression.
Participation of sympathoadrenal system in endotoxin shock
Authors: Hinshaw L. B. , Brake C. M. , Emerson T. E. , Jordan M. M. , Masucci F. D.
Published: December 2017

Experiments have been carried out on dogs, cats, and monkeys to determine the role of the sympathoadrenal system in endotoxin shock. It was found that hepatosplanchnic pooling in the dog after endotoxin is not dependent on an intact nerve supply to the abdominal viscera or the presence of the adrenals. Splanchnic denervation and adrenalectomy did not prevent portal hypertension, systemic hypotension, or intestinal hemorrhagic necrosis after endotoxin in the dog. Increases in foreleg vascular resistance and leg weight were found to be independent of the presence of the adrenals. Humorally induced vasoconstriction after endotoxin in cat and monkey preparations was found to be minimal. Hemoconcentration did not occur and net losses in weight were observed in cat and monkey perfused foreleg preparations. No evidence was obtained assigning detrimental roles to the sympathoadrenal system in the dog, cat, or monkey in this form of shock. Findings underscore the view that the primary mechanisms causing death from endotoxin may vary with the species.
Influence of fibrinogen on flow properties of erythrocyte suspensions
Authors: Wells Roe E. , Gawronski Thomas H. , Cox Paul J. , Perera Richard D.
Published: December 2017

The influence of fibrinogen on the flow properties of red cell suspensions (hematocrit 41) was studied by viscometry at low rates of shear (0.1–20 sec–1). These findings were correlated with sedimentation rates and photomicrographical studies of cell aggregation. Fibrinogen concentration was varied from 0.3 to 2.0 g/100 ml. The viscosity of the pure solutions of fibrinogen was independent of shear rate, ranging from 0.87 to 1.7 centipoise (cp) at 37 C. The viscosity of the cell suspensions at 10 sec–1 varied from 4.3 cp in 0.3 g/100 ml fibrinogen to 14 cp in 2 g/100 ml fibrinogen. All suspensions were markedly dependent on shear rate, viscosity increasing in exponential-like fashion as shear rate decreased. Extrapolation of plots of shear stress1/2 versus shear rate1/2 revealed the suspensions to sustain a finite stress without deformation or flow, the "yield value" increasing as fibrinogen concentration increased. Photomicrographs of dilute cell suspensions revealed the formation of cell aggregates and rouleaux, increasing in size and descent velocity as fibrinogen concentration increased.
Mechanisms of hemodynamic control of secretion of aldosterone in the dog
Authors: Gann Donald S. , Travis Randall H.
Published: December 2017

Changes in aldosterone and cortisol secretions were measured in response to constriction of the thoracic inferior vena cava and of the carotid arteries in intact and nephrectomized dogs. Aldosterone and cortisol secretions increased and decreased normally in response to caval constriction and release in nephrectomized animals. Carotid constriction in intact animals increased aldosterone secretion to the same extent as caval constriction, but without increasing cortisol secretion. Cortisol secretion rose after carotid constriction in vagotomized dogs. Nephrectomy led to transient low rates of aldosterone secretion in otherwise intact animals and prevented the increase of aldosterone secretion following carotid constriction in most, but not all, animals in which there was no evidence for ACTH release. Since carotid constriction decreases renin secretion, this effect of nephrectomy is probably independent of the renin-angiotensin system. The data suggest the presence of a mechanism involving the central nervous system, not mediated through ACTH release or the renin-angiotensin system, which is important in the physiologic control of aldosterone secretion, and which may involve an inhibitor of aldosterone secretion.
Specificity of insulin or oxytocin stimulation of protein synthesis in adipose tissue
Authors: Krahl M. E.
Published: December 2017

Insulin stimulates glucose uptake, fat synthesis, and incorporation of amino acids into protein of rat adipose tissue. Other agents having insulinlike effects on glucose metabolism have now been tested for their ability to promote protein synthesis in this in vitro system. Rat epididymal fat pads were incubated in Krebs bicarbonate medium containing glucose or pyruvate, acetate-1-C14 as precursor for lipids, or (in separate experiments) histidine-2(ring)-C14 as precursor for protein. Glucose uptake was measured by the glucose oxidase method, and radioactivity of lipid and protein fractions was estimated. Synthetic oxytocin (Sandoz), 0.1–10 U/ml, stimulated glucose uptake, acetate incorporation into lipid, and histidine-C14 incorporation into protein when glucose was present; unlike insulin, oxytocin did not enhance protein synthesis when pyruvate replaced glucose in the medium. RNA (1 mg/ml), nicotinic acid (0.001 m), and protamine sulfate (1 mg/ml) each stimulated glucose uptake and acetate incorporation into lipid, but did not enhance histidine-C14 incorporation into protein. It is concluded that in adipose tissue insulin has a specific effect on protein synthesis which cannot be mimicked by other agents which stimulate glucose uptake or lipid synthesis.
Effect of acetylcholine on urinary electrolyte excretion
Authors: Pinter G. G. , O'morchoe C. C. C. , Sikand R. S.
Published: December 2017

Acetylcholine was infused into the aorta of unanesthetized dogs above the origin of the renal arteries. It produced a statistically significant increase in Na, Cl, and K excretion rates and in renal plasma flow with respect to control values in the same experiments and to results obtained in separate control experiments on the same animals. No consistent change was found in glomerular filtration rate, urine flow, and osmolality. In similar experiments Pitressin was also infused. The renal effects of acetylcholine were slightly enhanced by Pitressin. It was concluded that the antidiuretic hormone was not an important mediator in the production of renal effects during acetylcholine infusion. The possible roles of increased medullary blood flow and of increased angiotensin production are discussed.
Effect of fasting on esterification of fatty acids by the small intestine in vitro
Authors: Gelb Alvin M. , Davidson Morton I. , Kessler Jacques I.
Published: December 2017

Fasting for periods up to and including 12–13 hr produced no significant change in esterification of myristic acid-1-C14 by the small intestine of hamsters in vitro. However, fasting for 18–19 hr, 22–24 hr, and 46–48 hr produced a significant decrease. This was partially reversed by feeding 1 hr prior to sacrifice, but was not altered by the ingestion of an inert substance. Esterification in fasted animals was significantly increased by glucose, parenterally prior to sacrifice, and when added in vitro. Intragastric administration of glycerol also increased esterification in fasted animals, although in vitro addition had no effect. An intermediate of glucose metabolism, dl-α-glycerophosphate, did not influence esterification. After a 46- to 48-hr fast no change in per cent protein in intestinal segments was noted.
White blood cell counts in bursectomized birds
Authors: Glick Bruce , Sato Koji
Published: December 2017

Birds were bursectomized before 3 days of age. Bursectomy did not significantly influence the total or absolute number of leukocytes at 12, 19, or 41 days of age. The bursectomized birds contained significantly fewer small lymphocytes at 5 and 41 days of age than medium lymphocytes. A single intravenous injection of 4 IU or 6 USP units of ACTH/100 g body weight significantly increased the absolute heterophil counts of both sham and bursectomized birds. However, only the bursectomized birds showed a significant decline in the absolute count of lymphocytes. The results suggest that the bursa of Fabricius is necessary for an optimum level of circulating lymphocytes. The bursa may influence the lymphocyte count by releasing specific cells or elaborating a humoral factor.
Influence of cerebral cortex in inhibition of oxytocin release induced by stressful stimuli
Authors: Taleisnik S. , Deis R. P.
Published: December 2017

Weight increase of a litter of rats during the course of 1 hr of suckling, after a 9-hr separation from their mothers, was taken as a measure of the amount of oxytocin released. The opening in the mother of an orifice in the cranium, on each side of the midline (bilateral trauma), or the fracture of one femur (unilateral trauma) caused a marked decrease in the litter's weight gain. Milk ejection so depressed was restored to the normal level by administration of oxytocin (20 mU/100 g). Stimuli arising from the traumatized area, therefore, exert a central inhibition on oxytocin release. In hemimammectomized animals, femoral fracture on the side with intact mammary glands has a greater inhibitory effect than the fracture on the opposite side. Topical application of 25% KCl on the cerebral cortex, in order to induce cortical spreading depression, caused the disappearance of the inhibition of oxytocin secretion. The influence of corticofugal systems on the reticular formation as a possible mechanism responsible for the suppression of the inhibitory action of stimuli on the release of oxytocin is discussed.
Localization for penile erection in medical frontal lobe
Authors: Dua Sushil , MacLean Paul D.
Published: December 2017

In extending a previous study the medial part of the frontal lobe of squirrel monkey was explored with respect to positive loci for penile erection. Strongly positive loci were found in precallosal cingulate gyrus and subcallosal region and in caudal part of gyrus rectus. Optimum stimulus parameters were moderately long pulses (1 msec) applied at a frequency of 20–30/sec. Mean latency of response was 4.9 sec for the precallosal cingulate region and 5.0 sec for the subcallosal region and gyrus rectus. Stimulation at positive loci evoked potential changes in the hippocampus. With pregenual cingulate stimulation a correlation was found between the appearance of erection and the recruitment of high-voltage slow hippocampal potentials. Associated behavioral effects included urination, cardiac slowing, respiratory acceleration, vocal changes, defecation, and salivation. Urination and cardiac slowing were the most frequent, with a respective incidence of 40 and 20%. Stimulation in ventral part of frontal lobe resulted in sneezing, head shaking, licking, chewing, and cardiac changes which might be associated with hippocampal evoked potentials and afterdischarges when electrodes were in or near olfactory bulb and tract. The findings are discussed in relation to preceding studies.
Relationship of depolarization to phosphorus metabolism and transport in excitable tissues
Authors: Abood L. G. , Koyama I. , Thomas Virginia
Published: December 2017

In the presence of Ringer solution containing a high concentration of potassium ions, the incorporation of orthophosphate-P32 into ATP and other organophosphates of the desheathed sciatic nerve or spinal ganglia of bullfrog was inhibited over 75%. The inhibition in calcium-free Ringer solution containing EDTA was somewhat less. With increasing external K+ there was a good correlation between the decrease in the resting potential of spinal ganglion cells and the inhibition of P32 incorporation into ATP and phosphocreatine. Since oxidative phosphorylation or carbohydrate metabolism was not inhibited by high K+, it was concluded that the K+ interfered with the transport mechanisms involved in orthophosphate-P32 exchange across the nerve membrane. Pi transport was believed to involve the following three chain-linked reactions: 1) carrier + P ⇌ carrier P; 2) carrier P ⇌ carrier + Pi; 3) Pi + ADP ⇌ ATP, where the first two reactions occurred in the membrane and the third within mitochondria. Reaction I or II was presumed to be K+ sensitive. The possible mechanisms involved in such an inhibition are discussed in terms of present-day theories relating to bioelectric phenomena.
Properties of axon membrane as affected by cobra venom, digitonin, and proteases
Authors: Narahashi Toshio , Tobias Julian M.
Published: December 2017

Electrical excitability and electrical constants of the lobster axon membrane have been measured under the influence of externally applied cobra venom, digitonin, or proteases in an attempt to gain insight into the molecular nature of membrane excitation. After the cobra venom which contained phospholipase A or after digitonin, resting potential, action potential, threshold potential, and membrane resistance decreased, while membrane capacity increased at least temporarily. After a mixture of trypsin and α-chymotrypsin, all of the parameters were kept almost unchanged. The results are in favor of the view that membrane phospholipid integrity is essential for the maintenance of membrane potential and excitability.
Separation of pepsin I, pepsin II A, pepsin II B, and pepsin III from human gastric mucosa
Authors: Seijffers Max J. , Segal Harry L. , Miller Leon L.
Published: December 2017

Page 1099: Max J. Seijffers, Harry L. Segal, and Leon L. Miller. "Separation of pepsin I, pepsin II A, pepsin II B, and pepsin III from gastric mucosa." Title in abstract, in issue table of contents, and in volume table of contents printed in error as title of companion paper which begins on page 1106. Should read the same as above title.
Separation of pepsinogen I, pepsinogen II, and pepsinogen III from human gastric mucosa
Authors: Seijffers Max J. , Segal Harry L. , Miller Leon L.
Published: December 2017

Page 1106: Max J. Seijffers, Harry L. Segal, and Leon L. Miller. "Separation of pepsinogen I, pepsinogen II, and pepsinogen III from human gastric mucosa." Title in abstract, in issue table of contents, and in volume table of contents printed in error as title of companion paper which begins on page 1099. Should read the same as above title.
Obesity from eating elicited by daily stimulation of hypothalamus
Authors: Steinbaum Eric A. , Miller Neal E.
Published: December 2017

Rats who were forced to overeat wet mash by electrical stimulation of the lateral hypothalamus 2 hr/day for 31 days became obese by maintaining an intake and rate of weight gain far greater than nonstimulated animals or animals similarly stimulated without food present. The rats stimulated without food present gained less weight over the 31-day period, ate less in the hour after each stimulation, but were not significantly different from the nonstimulated rats in total daily intake. In a second experiment, using a high-fat diet instead of wet mash, rats stimulated to eat varying fractions (0, 33, 66, 100%) of their normal daily intake in a short time each day were found abruptly to reduce their intake the rest of the day so that total daily intake remained normal.
Stimulus-response relationship in dog ventricle in vivo
Authors: Moulopoulos S. D. , Kardaras N. , Sideris D. A.
Published: December 2017

Electrical pulses of short duration were applied to the ventricular myocardium of 50 dogs. Several phenomena were observed in left ventricular pressure tracings and electrograms. Synchronization and desynchronization points between the heart and the stimulator (determined for stimuli of different frequency and strength) formed a curve which may be considered a "frequency-response" curve of the heart, thus indicating its "natural frequency." Transient phenomena appearing at the time of synchronization and desynchronization and during periodic synchronization may also indicate a similarity between the heart-stimulator system and a pair of coupled oscillators.
Dipole moment of isolated rabbit heart
Authors: Nelson C. V. , Waggoner W. C. , Gastonguay P. R.
Published: December 2017

The spatial dipole moment, M, of the isolated perfused rabbit heart at the center of a spherical container was determined during the cardiac cycle from three sets of bipolar voltage measurements. Average peak values for 12 experiments were 72,355, and 128 µa-cm for P, QRS, and T waves, respectively. Rates of change of M and spatial angle were also calculated. Successive excitation vectors are described by a sequence of numbers indicating directions in space. Comparisons between frontal plane vectors of in vivo and isolated hearts showed that, in QRS, average mean values of αf were 51° and 57°; for T these angles were 73° and –137°, indicating a reversal of direction. For P, the angles were 67° and –33°. The hypothesis is advanced that the spread of excitation in the atria is faster along the endocardial surface due to the relatively low resistivity of intracardiac blood; this results in a substantial dipole component perpendicular to the atrial wall.
Vascular effects of angiotensin and norepinephrine in the dog, cat, and monkey
Authors: Emerson Thomas E. , Hinshaw Lerner B. , Brake Charles M.
Published: December 2017

The direct effects of angiotensin and norepinephrine on forelimb vessels were compared in the dog, cat, and monkey in constant-flow forelimb preparations. Equiweight and equimolar injections and in some instances equiweight infusions were carried out. Brachial artery pressure (BAP), small vein pressure (SVP), and limb weight changes were continuously recorded. In some instances, intact, natural-flow preparations were employed. With equimolar injections in constant-flow limbs, angiotensin increased limb BAP and SVP more than norepinephrine in the dog and cat, and caused a significantly greater loss of limb weight in the dog. With equiweight doses, angiotensin caused a greater increase of cat forelimb BAP and SVP and monkey SVP; norepinephrine injection resulted in a greater increase of dog limb BAP and SVP and approximately the same increase of monkey BAP as angiotensin. Limb weight loss was not significantly different in any species. The initial SVP elevations produced by angiotensin and norepinephrine infusion were about equal, but the small veins became unresponsive to angiotensin after several minutes of infusion.
Hemodynamic alterations in left ventricular function consequent to ventricular pacing
Authors: Finney J. O.
Published: December 2017

Mongrel dogs were used to quantify left ventricular function (LVF) in response to subendocardial electrical pacing from three left ventricular sites and one right ventricular site (RVO). Ventricular pacing sites were compared with atrial pacing at constant heart rates. LVF was significantly diminished with ventricular pacing when left ventricular pressure, maximal rate of left ventricular pressure rise, cardiac output, stroke work, and stroke power were considered. Left ventricular pacing values were significantly greater than RVO pacing values. Developed tension (DT) and maximal rate of tension development (max. dT/dt) were recorded from a strain-gauge arch; max. dT/dt decreased disproportionately greater than the decrease in DT with ventricular pacing. The reduced LVF was shown to be independent of myocardial contractility, heart rate, end-diastolic fiber length, previous tension, and resistance to shortening. Temporal dyssynergy of left ventricular contraction was shown to be an important determinant of LVF in addition to the above variables. Left ventricular synergism must be taken into account when assessing myocardial contractility in the intact left ventricle.
Experimental diabetes mellitus induced by diet in the sand rat
Authors: Haines Howard , Hackel D. B. , Schmidt-Nielsen Knut
Published: December 2017

The sand rat ( Psammomys obesus), a rodent from the Near East and North Africa, becomes diabetic when raised on standard laboratory feeds. Animals collected in their natural habitat, on the other hand, show no signs of diabetes mellitus. Twelve animals were raised in the laboratory on Purina laboratory chow supplemented with fresh vegetables. Most of these animals developed severe diabetes mellitus as indicated by hyperglycemia, glucosuria, and pathological lesions including cataracts, obesity, and ß-cell degranulation and vacuolization of the pancreatic islet tissue. Ten animals raised entirely on fresh vegetables remained healthy with no signs of diabetes. Plasma and urine glucose concentrations, body weights, and the occurrence of cataracts are reported.
Effect of intestinal resection on bile salt absorption in dogs
Authors: Playoust M. R. , Lack Leon , Weiner I. M.
Published: December 2017

The efficiency of intestinal absorption of bile salts was evaluated by studying the rate of disappearance of radioactivity from the bile of dogs after the intravenous administration of sodium taurocholate-24-C14. Bile was sampled through an indwelling tube in the gall bladder. One day after a high-fat meal normal dogs retained 48% of the radioactivity; dogs with resection of the jejunum retained 48%, whereas those with resection of the ileum retained only 3% in the bile. This is consistent with previous observations that the ileum is the site of bile salt absorption in vitro and in anesthetized animals. Animals with resection of the ileum exhibited significant steatorrhea; however, three-fourths of the ingested fat was absorbed in spite of almost complete failure to absorb bile salts. This indicates that fat and bile salts are not normally absorbed together. Elimination of enterohepatic circulation of bile salts by resection of the ileum contributes to the observed steatorrhea.
Efflux of chloride through cell surfaces of frog gastric mucosa
Authors: Villegas Leopoldo
Published: December 2017

Concentration, effluxes, and exchangeable chloride were studied in the isolated frog gastric mucosa. The tissue chloride, 51.6 ± 0.7 (se) mm/kg wet wt, is totally exchangeable. The tissue chloride concentration increases to 68.0 ± 2 2 (se) mm/kg wet wt after incubation between two chloride solutions. Using sulfate secretory solution this value became 66.9 ± 1.3 (se) mm/kg wet wt. Using sulfate nutrient solution a decrease to 126 ± 1.1 (se) mm/kg wet wt was observed. Tissue chloride effluxes were described by two exponentials; one (extracellular chloride) had a time constant of 117 ± 04 (se) hr–1; the other (cellular chloride) had a time constant of 1.13 ± 0.07 (se) hr–1. The ratio of the effluxes through both surfaces, ΔAm/ΔAs was 1.59 ± 0.16 (se) in mucosae maintained between sulfate solutions. This ratio increases to 2.13 ± 0.10 (se) by the use of histamine in both solutions or decreases to 0.51 ± 0.05 (se) by the use of chloride solutions. It is proposed that a) there exists chloride passive diffusion through both surfaces of the cellular membrane, b) the barrier sensitive to histamine is close to the mucosal surface, where the active transport of chloride is located, and c) a barrier requiring exchange of chloride is located close to the serosal face of the cells.
Inhibition of rat intestinal and rat kidney mutarotase by actively transported sugars
Authors: Bailey J. Martyn , Pentchev P. G.
Published: December 2017

Properties of an enzyme isolated from rat intestine and rat kidney and which catalyzes mutarotation of sugars are described. Mutarotation of d-xylose, d-glucose, d-galactose, and l-arabinose was accelerated by the enzyme. Interaction of a number of sugars with the active site was examined by measuring inhibition of enzyme-catalyzed mutarotation of α-d-glucose. Based on this criterion, two sugars with no mutarotable hydroxyl (α-methylglucoside and 1-deoxyglucose) interacted strongly with the enzyme protein. Hexose sugars actively transported by intestine (d-glucose, d-galactose, 6-deoxy-d-galactose, α-methylglucoside, and 1-deoxy-d-glucose) inhibited the enzyme strongly. A number of hexoses and hexitols reportedly not actively transported (d-mannose, d-glucosamine, 2-deoxy-d-glucose, 2-deoxy-d-galactose, d-sorbitol, galactitol, and d-fructose) showed only alight inhibition. Pentoses with the same configuration at carbon 2 as d-glucose (l-arabinose and d-xylose) were good inhibitors of the enzyme; those differing at carbon 2 (d-lyxose and d-arabinose) were not. The enzyme possesses certain of the qualities of the hypothetical carrier or "permease" postulated for sugar transport. Possible significance of some inconsistencies with this hypothesis is discussed.
Urine and papilla concentrations during transition from hypotonic to hypertonic urine
Authors: White H. L. , Rolf Doris
Published: December 2017

Dogs in water diuresis, with high urine flow and low urine osmolality and sodium concentration, had papilla fluid osmolality of 398 milliosmols/kg H2O and papilla fluid sodium concentration of 116 millimolal. At 5.5 min after laparotomy and 100 mU of vasopressin intravenously, papilla fluid osmolality and sodium concentration showed no significant rise, but urine osmolality and sodium concentration had risen greatly. At longer intervals, up to 13 min, papilla osmolality rose to above 600 mM with a further rise in urine osmolality; osmotic equilibration between urine and papilla fluid was attained at about 10 min Papilla fluid sodium concentration rose after 5.5 min Cortex fluid remained isosmolal with plasma.
Carotid sinus reflex in cat: effect of prior external carotid artery clamping
Authors: Abraham G. J. S. , Share N. N. , Wang S. C.
Published: December 2017

Intrasinusal and systemic arterial pressure changes resulting from occlusion of the common carotid arteries (CCO) in vagotomized cats were recorded and compared with those in which the external carotid arteries were previously clamped. The CCO responses were similar under chloralose and pentobarbital anesthesia, and were unaltered by positive-pressure respiration. Prior bilateral external carotid artery clamping (ECC) significantly reduced the initial fall in intrasinusal pressure and the reflex pressor response. Injections of acetic acid into the sinus region reduced the reflex pressor response despite a greater fall in intrasinusal pressure after CCO. Following acid treatment, prior ECC generally reduced the reflex pressor response to a lesser degree than before treatment. It is concluded that in vagotomized cats, there is no difference between chloralose and pentobarbital anesthesia or positive-pressure and spontaneous respiration on the CCO response. The magnitude of the reflex pressor response apparently depends on the degree of baroreceptor deactivation and chemoreceptor activation. The results are discussed further in terms of differences between the cat and the dog.
Influence of sex hormones on thrombosis of left atrium in Syrian (golden) hamsters
Authors: Sichuk George , Bettigole Richard E. , Der Bela K. , Fortner Joseph G.
Published: December 2017

Spontaneous thrombosis of the left atrium is common in aged male and female Syrian (golden) hamsters in our laboratory and occurs at a younger age in females. At necropsy, the thrombus almost completely occludes the swollen atrium and is widely attached to the endocardium Endocrine manipulations unexpectedly influenced the occurrence of these thrombi. Following gonadectomy, development of such thrombi was hastened in male hamsters but was uninfluenced in female hamsters. Testosterone propionate given subcutaneously inhibited left atrial thrombosis in male and female gonadectomized hamsters. Norethynodrel with mestranol given subcutaneously to adult male hamsters was followed by an increased incidence of left atrial thrombosis. This increase may have been due to suppression of endogenous androgen production or action, or both. Microbiological studies of left atrial thrombi were negative. There was no correlation between the occurrence of left atrial thrombi and platelet numbers, prothrombin time, glass-tube clotting time, plastic-tube clotting time, or Russell viper-venom time. Partial thromboplastin time was lengthened in female but not in male hamsters with a left atrial thrombus.
Sulfobromophthalein sodium (BSP) conjugation and excretion in fetal guinea pigs
Authors: Schenker Steven , Goldstein Joe , Combes Burton
Published: December 2017

Unconjugated and conjugated S35-labeled BSP were administered to viable fetal guinea pigs with intact placental circulation. Guinea pig placenta was virtually impermeable to unconjugated and conjugated BSP, thus permitting a comparison of the disposition of both dye compounds in the fetus, and additional comparison with adult guinea pigs receiving comparable weight-adjusted doses of BSP. Although conjugated BSP disappeared more slowly from plasma than unconjugated BSP in fetal and adult animals, it was delivered more rapidly into bile, indicating a shorter hepatic phase for conjugated BSP. The rate of delivery of both dye compounds into bile was considerably decreased in fetal guinea pigs when compared with values in adult animals. Biliary excretion of administered unconjugated BSP was disproportionately depressed, however, indicating that conjugation of BSP was impaired. Excretion of conjugated BSP into bile was also impaired in the fetus. Since conjugation appears to be impaired to a greater extent than excretion of conjugated and unconjugated BSP into bile in near-term fetal guinea pigs, conjugation, rather than excretion, is rate limiting in BSP delivery into bile in these animals.
Fever produced by microinjection of typhoid vaccine into hypothalamus of cats
Authors: Villablanca J. , Myers R. D.
Published: December 2017

In unanesthetized cats, 1 or 2.5 µliters typhoid vaccine were injected into several areas of the hypothalamus, the lateral cerebral ventricle, and other areas of the brain. The concentrations of the pyrogen used ranged from 1/8 to 1/16,000 of the dose required to produce fever by the intravenous route. Fever was obtained in all experiments in which the vaccine was applied to the anterior hypothalamus or to the lateral cerebral ventricle. No significant rise in temperature occurred following injections into other brain areas unless extremely high doses were employed. The short latency and the rapid rise in temperature following the injection of typhoid vaccine into the anterior hypothalamus suggest that pyrogens act on the cells of this diencephalic structure when fever is produced.
Phase portraits of dystrophic and nondystrophic mouse muscle-fiber action potentials
Authors: Evans Titus C. , Schottelius Byron A.
Published: December 2017

Intracellular action potentials from normal, control nondystrophic and dystrophic mouse soleus muscle fibers were recorded in both voltage-time and phase-portrait plots. Flattening of a normally curved portion in certain dystrophic muscle-fiber phase portraits suggested a greater than usual secondary entry of sodium ions after the peak of the action potential. Low-chloride studies excluded an abnormal chloride current as the cause of the flattening. It appears that inactivation of sodium ion conductance may be delayed or reduced, or both, in certain fibers of mice with hereditary muscular dystrophy. This is consistent with a general increase in membrane permeability. No definite negative afterpotential was noted in most mouse muscle-fiber action potentials.
Vasopressin potentiation of catecholamine actions in dog, rat, cat, and rat aortic strip
Authors: Bartelstone Herbert J. , Nasmyth Peter A.
Published: December 2017

This study was undertaken to determine whether arginine vasopressin, infused or injected in doses within known physiological ranges, can alter pressor responses to injected or endogenously liberated catecholamines. In 8 pentobarbital-anesthetized dogs, 14 pithed rats, and 7 spinal cats, the pressor responses to catecholamine injections were definitely potentiated by administration of nonpressor doses of vasopressin. In eight dogs anesthetized with N2O-O2, readily reproducible pressor responses to bilateral carotid artery occlusion were subsequently potentiated by infusions of vasopressin. Vasopressin also potentiated both isometric and isotonic responses of 37 rat aortic strip preparations to norepinephrine or epinephrine added to the Krebs-bicarbonate bath. Vasopressin, in physiological dose ranges, potentiates pressor responses to catecholamines by a direct rather than a central action. Endogenously liberated vasopressin may play a role in the responsiveness of vascular smooth muscle to endogenously liberated catecholamines in dog, rat, and cat.
Blood viscosity and in vitro anticoagulants
Authors: Mayer George A. , Kiss Odon
Published: December 2017

The viscosity of whole blood is not affected by the addition of 5 units of purified heparin in dry form or 1.2 mg EDTA (Na2) to 1 ml of blood, but it is decreased by potassium oxalate in a concentration of 2.5 mg/1 ml.
Effect of hypoxia on secretion of ACTH in the rat
Authors: Marks B. H. , Bhattacharya A. N. , Vernikos-Danellis Joan
Published: December 2017

Body weights, organ weights, and blood and pituitary ACTH concentrations were determined in rats exposed continuously to 20.9, 15.0, or 10.0% O2 atmospheres at normal barometric pressure for periods ranging from 3 to 120 hr. Hypoxia resulted in some loss of body weight, and loss of weight of the thymus and the ovary. The weight of the adrenals increased. Blood ACTH rose rapidly after exposure to hypoxic conditions, remaining elevated for the duration of the experiment. Control animals (20.9% O2) placed in the same chamber had detectable blood ACTH only at the 3-hr sampling time. Pituitary ACTH also rose rapidly during hypoxia, the elevation being greatest with the most severe hypoxic state. The rate of ACTH synthesis and secretion in the resting state and during the stress of hypoxia is discussed.
Effect of metal ions on in vitro gluconeogenesis in rat kidney cortex slices
Authors: Rutman Julia Z. , Meltzer Lawrence E. , Kitchell J. Roderick , Rutman Robert J. , George Philip
Published: December 2017

The effect of metal ions on glucose formation from amino acids and glycolytic and tricarboxylic acid cycle intermediates has been examined in rat kidney cortex slices in vitro. Of the metals tested, only Mn++ and Ca++ have been shown to be stimulatory, while Zn++, Cu++, and Cd++ are inhibitory. The case of Mn++ activation is of particular interest because Mg++ ions are inactive in this system, despite the similarities usually observed in the in vitro systems. The stimulation of gluconeogenesis from α-keto acids is comparable for both Ca++ and Mn++, in contrast to the lack of a Mn++ effect with the homologous l-α-amino acids. Evidence is presented as to the possible significance of metal ions in regulating carbohydrate metabolism.
Effect of low pO2 on Qo2, Na22 efflux, and contractility of muscles
Authors: Whalen William J. , Bosch Priscilla , Dimants Andrejs
Published: December 2017

Previous experiments suggested that the in vivo consumption of O2 by the cell is normally limited by the pO2 in the cellular environment. We suggested that if the pO2 exceeds a certain minimal level, some or all of the energy from the "extra" respiration may be directly converted to heat. To further test the hypothesis, 39 isolated frog sartorii were placed in respirometers containing Ringer-bicarbonate solution (at 22 or 27 C) equilibrated with gas mixtures of various oxygen tensions. (All gases contained 2% CO2.) The Qo2 of muscles exposed to 98% O2 for 6–7 hr reached a stable value which was about 200% of the stable value for muscles exposed to 25% O2 for the same period of time. In other experiments the depression of the Qo2 in 25% O2 was shown to be reversible. The ability to develop tension, as judged by occasional test contractions, was not impaired in 25% O2. The amount of lactic acid liberated from the muscles was small and was independent of the pO2. In additional experiments with similar muscles exposed to either 25% O2 or 98% N2 for 5–7 hr, neither the Na22 efflux nor resting membrane potential differed significantly from the values obtained in 98% O2. The data are consistent with the hypothesis.
5-Hydroxytryptamine bradykinin and histamine as mediators of inflammatory hyperesthesia
Authors: Gilfoil Thomas M. , Klavins Inese
Published: December 2017

Changes in threshold to pressure and volume were measured in rat paws injected with 5-HT, bradykinin, or histamine separately and in combination to find out if one or more of these agents mediate hyperesthesia of experimentally inflamed rat paws, and also to assess the role of the mechanical factors imposed by the attendant edema. Subcutaneous perfusates obtained at the time of maximal hyperesthesia from yeast-inflamed paws were bioassayed for 5-HT, bradykinin, and histamine content. Intensity of hyperesthesia correlated well with dose of 5-HT or bradykinin, but not with the degree of accompanying edema. Hyperesthesia induced by 10 µg 5-HT was potentiated in paws injected simultaneously with 10 µg bradykinin. However, a 30- to 45-min delay in appearance of maximal hyperesthesia induced by 5-HT and bradykinin injected alone or in combination suggested an indirect rather than a direct effect. Perfusates from yeast-inflamed paws contained no 5-HT or histamine and only infrequently a bradykinin-like substance. We concluded that the hyperesthesia of experimentally inflamed rat paws was not mediated by a direct action on subcutaneous nerve endings of 5-HT, bradykinin, or histamine separately or in combination, and that its intensity was not indicated by the degree of attendant edema.
Conversion of acetate to lipids and CO2 by liver of rats exposed to acceleration stress
Authors: Feller D. D. , Neville E. D.
Published: December 2017

Male Sprague-Dawley rats in age groups from 1 to 20 weeks were centrifuged at 4.5 g for periods of 0.5 hr-14 days. Slices of liver, kidney, and inguinal adipose tissue were incubated with C14-labeled acetate, and the resulting isotopic CO2 and lipids were measured. When compared with tissues from control rats, liver and adipose tissue from nonfasted centrifuged rats showed increased formation of C14-labeled lipids while kidney showed a decrease. Liver from fasted centrifuged rats also showed increased formation of C14-labeled lipids when compared to fasted noncentrifuged controls. The increase in acetate conversion to lipids varied with age of animal and duration of exposure to acceleration. No significant change in acetate-C14 oxidation to C14O2 by liver was noted in either fed or fasted centrifuged animals as compared to their corresponding controls. The total lipid content of liver from rats that were exposed to centrifugation was lower than that from control animals.
Potassium, sodium, and iodide transcapillary exchange in the dog heart
Authors: Yudilevich David , de Julián Pablo Martín
Published: December 2017

Simultaneous first-passage dilution curves of the electrolytes were performed in the blood-perfused isolated dog heart. Quantification of transcapillary exchange was accomplished by means of the parameters "fractional extraction" from the blood, E, and "fractional turnover rate of exchange" of the interstitial compartment with the blood, k. The results show that E for Rb86+ and K42+ is 0.69 ± 0.08, for Na22+ 0.74 ± 0.12, and for I131– 0.54 ± 0.03. The values of k for Na22+ ranged between 0.11 and 3.00 min–1 and for I131 between 0.76 and 3.54. The k's varied with the blood flow but apparently the E's did not. There was a high linear correlation between the plasma clearance of the ions and the flow. From the data the heart interstitial fluid volume was calculated as 0.15 ± 0.04 ml/g. In some experiments various ions were studied simultaneously and the E's used to compute permeability-surface products, PS. The PS ratios for sodium and potassium were not significantly different from the ratio of free diffusion in water constants.
Postural stability in the dog
Authors: Brookhart J. M. , Parmeggiani P. L. , Petersen W. A. , Stone S. A.
Published: December 2017

Positional stability in quietly standing dogs has been evaluated in terms of force records from individual feet and the position of the center of gravity. All four dogs carried approximately 60% of their total weight on their anterior feet and roughly 50% of their weight on each side. Within-trial variations from the mean of the fraction of total weight borne on any one foot ranged from 0.3 to 4.5% with a mean of 1.4%; between-trial variability ranged from 1.1 to 2.7%. Continuous movement of the center of gravity occurred within an area measuring approximately 1.5 cm on a side. Shifts in weight distribution within and between trials occurred in a variety of patterns which could be described in terms of the behavior of pairs of transverse, longitudinal, and diagonal couples. Preliminary observations of the reactions to a sudden disturbance confirm the hypothesis that quiet stance is accomplished through central nervous regulation. It is concluded that the trained dog behaves with a sufficient level of predictability to permit its use as a subject in a further examination of the postural control system.
Short-term salt preference of potassium-deprived rats
Authors: Zucker Irving
Published: December 2017

Short-term selection of salts was studied in young rats maintained on a potassium-free diet. When offered a choice between a KCl solution and one of five NaCl solutions, these animals showed a greater preference than controls for four of the five NaCl solutions. Moreover, they preferred the NaCl solutions over the KCl solution for four of the five concentrations of NaCl tested. Control animals preferred NaCl over KCl at only one of the NaCl concentrations. The initial choice of NaCl by the potassium-deprived rats is, by definition, independent of taste and postingestional factors, and is in part, perhaps, under the control of olfactory stimuli emanating from the salt solutions. The preference for NaCl over KCl was diminished by maintaining potassium-deficient rats on a diet high in sodium content. It was tentatively concluded that the increased preference for NaCl by rats fed diets low in potassium content but adequate in all other respects reflected an increased utilization of sodium.
Reflex changes in heart rate and ventilation induced by central blood pressure changes
Authors: Kinnison G. L. , Breeden C. J. , Carmack R. M. , Ballard B. M. , Mel P. J. , Hemingway A.
Published: December 2017

To determine the existence and assess the importance of reflex mechanoreceptor areas other than carotid and aortic baroreceptor sites in dogs, balloon and monitoring catheters were placed in the pulmonary artery proximal to the bifurcation, in the inferior vena cava, and in the thoracic aorta above the diaphragm. Inflation of these balloons made it possible to produce a variety of pressure distribution patterns in the circulation. Pressures were recorded from the bifurcation of the pulmonary artery, right and left atria, aortic arch, and intrathoracic esophagus to obtain evidence for the existence of blood pressure reflexes originating above the diaphragm. The results contain quantitative evidence for the following reflexes in dogs anesthetized with chloralose, and breathing normally with closed chest: 1) the Bainbridge "effect;" 2) the well-known barostatic reflexes, except that respiration rate was found to be independent of arterial pressure; 3) a previously unreported reflex: when the pulmonary artery pressure is lowered (the right atrial and aortic pressures being maintained constant) there results an immediate increase in respiration rate and depth without a concomitant change in heart rate.