bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of urinary pH on the renal concentrating mechanism
Authors: Goodman Alvin , Levitin Howard
Published: December 2017

The influence of an alkaline urine on the maximum concentrating ability of the rat during antidiuresis and the Tch2o of dogs during osmotic diuresis was examined under conditions of alkali loading. In the rat, alkali loading induced an acute and reversible decrease in the maximum concentrating ability which could not be attributed to potassium deficiency or an associated increase in solute output. During osmotic diuresis in the dog, no change in the Tch2o accompanied alkalinization of the urine. It is suggested that the pCO2 of the urine plays an important role in determining the observed changes.
Resting potential dependency on external potassium in Amphioxus muscle
Authors: Geduldig Donald S.
Published: December 2017

The resting potential of Amphioxus muscle was determined by using an internal micropipet electrode. The effect of external potassium concentration was studied. From the curvature of the semilogarithmic plot of membrane potential versus external potassium concentration, an estimate can be made of the relative permeability of the membrane (in the resting state) to Na+ and K+. The permeability to sodium is 0.03 of the permeability to potassium. Structural features which may be responsible for this permeability difference are noted.
Effects of dietary lipids on hepatic protein synthesis and lipid metabolism in the rat
Authors: Saito Shiro , Fillios Louis Charles
Published: December 2017

The effects of dietary cholesterol, cholic acid, or high fat on hepatic protein synthesis were studied in rats. The feeding of 1.5% cholesterol or 20% corn oil in the diet caused significant inhibition of leucine-C14 incorporation into protein in vitro; the effect of 0.5% cholic acid was less striking. The feeding of a diet containing all three factors (cholesterol, cholic acid, and high fat) resulted in the greatest inhibition of hepatic protein synthesis in vitro. This dietary effect was confirmed in vivo when methionine-S35 incorporation into liver proteins was measured in male and female rats. Comparison between the control purified diet and laboratory chow showed no differences. Appropriate experiments in vitro employing 105,000- g cell sap fractions and microsomes ruled out any apparent effect of diet on the activation and transfer of leucine-C14 to the microsomal templates. Furthermore, no effect was noted in leucine-C14 incorporation into soluble RNA in vitro. It appears that the changes in protein synthesis are consistently associated with a "defect" in the microsomal fraction.
Hepatic blood supply and control of deoxyribonucleic acid synthesis in liver
Authors: Lieberman Irving , Short John
Published: December 2017

Permanent ligation of the branch of the hepatic portal vein supplying a portion (67%) of the liver causes, in the nonligated lobes, increases in the rate of RNA synthesis, in the electrophoretic mobility of the nuclei, and in DNA formation that are indistinguishable from those that follow partial hepatectomy. Temporary ligation of the branch vessel causes some or all of these changes in the nonligated lobes depending on the length of the ligation time. Thus, a ligation period of 0.5–2 min produces the alterations in RNA formation and in the nuclear membrane, but hepatic DNA synthesis is unaffected. Ligation of the branch vessel for 10 min yields, in addition, a marked increase in DNA formation. The possibility is considered that the changes in RNA synthesis and in the nuclear membrane result directly from the vascular disturbance caused by partial hepatectomy or the ligation of the portal vein branch. At least some of the alterations required to stimulate DNA formation, however, appear to have a different etiology, possibly related to a loss of liver function.
Ventricular function in the newborn lamb
Authors: Downing S. Evans , Talner Norman S. , Gardner Thomas H.
Published: December 2017

The present study was initiated with the objective of evaluating in the newborn those aspects of ventricular mechanics which form the basis of the Frank-Starling relation, and which permit a determination of changes in the inotropic state of the heart. Left ventricular function was studied in lambs, 12 hr to 5 days old, utilizing a preparation designed to permit control and measurement of systemic arterial pressure (AP), cardiac output, heart rate (HR), and temperature. Continuous measurements of arterial Po2 and pH were made. These data permitted the construction of ventricular function curves relating stroke volume, mean ejection rate, and stroke work and power to left ventricular end-diastolic pressure, at constant AP and HR. In all preparations the Frank-Starling relation was found to be operative. Norepinephrine infusion, 1–2 µg/kg per min, resulted in a substantial increment of both force and speed parameters, thereby demonstrating the ability of the newborn heart to alter its inotropic state. Severe metabolic acidosis did not inhibit the response of the myocardium to norepinephrine.
Hemodynamic alterations produced by intra-arterial gas emboli
Authors: Bond Robert F. , Durant Thomas , Oppenheimer Morton J.
Published: December 2017

Hemodynamic alterations in the femoral arterial bed after experimental gas emboli are manifested as a primary phase of increased resistance followed by a more prolonged phase of decreased resistance. The purpose of this study was to determine the site of the resistance changes and to observe other physiological variations which occur in the femoral bed as a direct result of the emboli. Capillary blood flow in skeletal muscle was studied by Na24 clearance and a-v O2 difference methods. The responses to gases with different solubility coefficients were compared. Large-vessel responses were observed cinefluorographically. The influence of preinjection vascular tone was studied by infusion of norepinephrine and acetylcholine during the gas injection. Analysis of the data suggests that the emboli within the resistance vessels initiate a stimulus to the smooth muscle of these vessels which results in an initial phase of constriction and probably obstruction followed by decreased resistance which was interpreted as an ascending wave of relaxation.
Reninlike activity in kidneys of dogs with neurogenic and nephrogenic hypertension
Authors: Bliddal J. , Masson G. M. C. , McCubbin J. W.
Published: December 2017

Reninlike activity in dog kidneys was measured using a simple but reliable procedure that involved injection of saline extracts of portions of renal cortex into nephrectomized assay rats. In dogs with neurogenic hypertension the amount of pressor material in the renal cortex was within the normal range. In dogs with one kidney wrapped in cellophane the opposite untouched kidney became almost completely depleted of pressor material despite no appreciable rise in arterial pressure. Both findings support the hypothesis that a humoral factor, presumably of renal origin, is more important than systemic arterial pressure in determining the amount of pressor material in the kidney. As groups, dogs made hypertensive by cellophane perinephritis, or by constricting a renal artery and contralateral nephrectomy, showed an increase in reninlike activity in the manipulated kdiney, but in individual experiments there was no correlation between the amount of pressor activity and the level of the arterial pressure.
Electrolyte secretion from rabbit pancreas in vitro
Authors: Rothman S. S. , Brooks F. P.
Published: December 2017

A technic has been developed permitting direct collection of undiluted rabbit pancreatic secretion in vitro without vascular perfusion. The rates of secretion and output of electrolytes were comparable to those obtained in situ. When secretin was added, flow and bicarbonate concentration increased. Secretion in vitro ceased when inhibitors of glycolysis and aerobic metabolism were added to the bathing solution. The sodium concentration of the secretion exceeded that of the bathing solution in all but one observation. Potassium concentrations in secretion were linearly related (slope = 0.93) to the potassium concentration in the bath over a range of 5.8–12.0 mm. After 4–5 hr in vitro, the total carbon dioxide concentration of secretion had decreased while chloride concentration increased with no significant change in the rate of secretion. When secretory rate changed over a range of approximately 30–600 µliters/hr, chloride and carbon dioxide output varied directly with the rate of secretion. The osmolarity of the bathing solution and secretion were always equivalent. These results are incompatible with direct plasma filtration and bicarbonate-chloride exchange as the main mechanisms of pancreatic secretion.
Skeletal response of rats exposed to reduced barometric pressure
Authors: Hunt Roger A. , Schraer Harald
Published: December 2017

The response of the rat skeleton to hypoxia (380 mm Hg) has been investigated. The femur images in calibrated radiographs taken at 2-week intervals were analyzed photodensitometrically. Femurs were also excised from other rats to obtain density and volume measurements by displacement methods. Hematocrit values and body weights were recorded. Differences between femur densities and between femur dry weights (hypoxic group 13 and 20% less, respectively) developed during the first 31 days. Differences between femur volumes, between body weights, and between hematocrit values (hypoxic group 8% less, 16% less, and 60% more, respectively) developed during the first 15 days. However, the difference between marrow cavity volumes (hypoxic group 22% more) developed between days 15 and 31. The interpretation is that during the first 15 days when marrow cavity volumes did not differ, the large hematocrit value was caused by increased hemopoietic activity of marrow present at the onset of hypoxia. Subsequently, marrow cavities become 22% larger than normal, facilitating production of blood at a more nearly normal activity.
Heart rate of the preweanling rat and its autonomic control
Authors: Wekstein David R.
Published: December 2017

The heart rate of the rat at birth is about 300 beats/min, increases to 360 beats/min within 3 days, and remains there until the animal is about 10 days old. From 10 to 21 days the heart rate again increases to a maximum of about 500 beats/min. When reserpine is used to selectively block adrenergic sympathetic function the rise in heart rate that occurs during the first 3 days is only slightly modified, but the rise in heart rate from 10 days onward is completely prevented. Atropine, however, has no effect on heart rate at all ages tested. When newborn rats are kept at a body temperature of 37 C and then at 40 C, the average heart rate increases 7%. Three-day-old animals have a 19% increase, whereas 6-day-old animals show a 46% increase. When nerve-growth-factor antiserum is used to destroy sympathetic function, the expected hyperthermic tachycardia does not appear. It is concluded that in the first 6 days of the rat's life sympathetic control over the heart rate is minimal, but from then on the sympathetic nervous system continuously exerts a positive chronotropic effect. The parasympathetic nervous system does not seem to be involved.
Effect of deoxycorticosterone on sodium appetite of intact and adrenalectomized rats
Authors: Wolf George
Published: December 2017

The effect of DOC on sodium chloride (saline) intake was studied in intact and adrenalectomized rats under "two-bottle" self-selection conditions. It was found that in adrenalectomized rats low doses of DOC produced a decrease in saline intake (restoration of sodium-retaining ability), whereas high doses produced an increase in saline intake (stimulation of sodium appetite). At high doses, however, intact rats consumed more saline and manifested a greater preference for it than did similarly treated adrenalectomized rats. Treatment with corticosterone increased both absolute saline intake and saline preference of DOC-treated adrenalectomized rats.
Cytological basis of decrease in muscle strength during starvation
Authors: Goldspink Geoffrey
Published: December 2017

The effect of partial starvation on the mouse biceps brachii was to cause muscle fibers existing in a "large phase" of diameter 42 µ to revert back, in an "all-or-nothing" manner, to a "small phase" of 23 µ diameter. During a subsequent recovery period the reverse change took place at the same rate as during starvation. The time for one phase to be converted into the other phase was in the region of 1–2 days. When a large-phase fiber reverts back to the small phase there is a disproportionately large decrease in its myofibril content due to a decrease both in the number and in the size of its myofibrils. This results in a difference in the packing of the myofibrils in these two phases. Measurements of muscle strength were made and these could be directly related to the changes in the myofibril content of the fibers. The tension that a single small-phase fiber and a single large-phase fiber could develop was calculated to be 2.8 mg and 17 mg, respectively.
Blood chemistry of the bottlenose dolphin (Tursiops truncatus)
Authors: Medway William , Geraci Joseph R.
Published: December 2017

The blood chemistry of six adult bottlenose dolphins ( Tursiops truncatus) kept in an artificial environment (simulated sea water) has been studied. Whole blood, plasma, and serum constituents are compared to those of the dog and horse. The plasma sodium, plasma chloride, and serum albumin levels appear to be higher while the α1, α2, and ß-globulin levels appear to be lower than those found in dogs and horses. The blood urea nitrogen values (mercury-combining capacity) are considerably higher than those found in dogs and horses.
Effects of zinc on cardiac muscle contraction
Authors: Nayler Winifred G. , Anderson Juliet E.
Published: December 2017

The effect of 0.001–5 mm Zn++ on the contractions of dog, rabbit, and monkey papillary muscles, rat atria, isolated rat hearts, and toad and tortoise ventricular muscle was investigated. Zn++ depressed the contractions of all cardiac muscle preparations tested; the negative inotropic response was associated with an unchanged duration of contraction and a prolonged action potential. Zn++ > 0.5 mm caused mechanical arrest; perfusion of Zn++-arrested amphibian preparations with 100 mm K+ solution resulted in contractures equal in magnitude to that evoked by similar perfusion with 100 mm K+ in the absence of Zn++. It is concluded that the action of Zn++ on cardiac muscle differs essentially from that described for skeletal muscle.
Vascular volume changes resulting from vasodilation of the dog forelimb
Authors: Baker Carleton H.
Published: December 2017

In an isolated dog forelimb preparation, perfusion pressure, venous outflow pressure, and blood flow were determined. Vascular volume changes were estimated by arterial injections of red cells-Cr51 and albumin-I131 and by changes in limb weight. Measurement of the recovery of the above two indicators as well as the diffusible indicator Rb86Cl was made. Net capillary filtration of fluid was also determined from changes in weight of the limb. Measurements were made: 1) under control conditions, 2) during vasodilation with acetylcholine, 3) following 25 ml/min increment in flow rate through the dilated bed, 4) following another 25 ml/min increment in flow rate. Following vasodilation, the increase in vascular volume determined by weight change was significantly smaller than that measured by the indicators, recovery of Rb36Cl was significantly less than during the control, and the net transfer of fluid was increased. Each time flow was increased, the red cells-Cr51, albumin-I131, and weighing device measured similar increases in vascular volume.
Thrombelastographic patterns produced by fibrinolytic agents incorporated in fibrin
Authors: Astrup Tage , Egeblad Klas
Published: December 2017

Lysis of clots produced from bovine fibrinogen and bovine thrombin in the presence of fibrinolytic agents was followed by thrombelastography in order to obtain information about the mechanism of clot lysis in a standardized, purified system, which simulated physiological clot lysis. A characteristic difference in the thrombelastographic patterns was found between lysis of clots produced by preformed plasmin and by activators of plasminogen. With activator plasmin formation occurred at a late stage of the total period of clot lysis; plasmin was then produced in large quantities and the resulting lysis was extremely rapid. A correlation curve between concentration and lysis time yielded in all instances a straight line in a double logarithmic graph. There was a characteristic difference between the slopes obtained with plasmin and with activator, indicating different mechanisms of reaction.
Trapping of urea by red cells in the kidney
Authors: Chinard Francis P. , Goresky Carl A. , Enns Theodore , Nolan Mary F. , House R. Winifred
Published: December 2017

Outflow patterns of T-1824, urea, thiourea, and creatinine have been determined in the dog kidney in vivo and in situ as a function of the arterial hematocrit by means of the multiple indicator-dilution technique. The mean transit times of T-1824, urea, and creatinine decrease and converge as the hematocrit decreases. The outflow patterns of urea are anomalous: a) there is precession of urea over creatinine and thiourea; b) the transit times of urea are shorter than those of creatinine and thiourea; c) the recoveries of urea are greater than those of creatinine at normal and high hematocrit values. Thiourea has a longer equilibration time with red cells than urea. Prior incubation of thiourea with red cells results in precession of thiourea over urea. These results are considered evidence of transient trapping of urea in red cells during their passage through the glomerular capillaries. The similarity of the urea outflow curves to curves of substances known to participate in a membrane carrier transport system by the tubule cells from the antiluminal side suggest that urea may participate in a similar system.
Lateral cervical nucleus of the dog: anatomical and microelectrode studies
Authors: Kitai S. T. , Ha H. , Morin F.
Published: December 2017

The lateral cervical nucleus (LCN) of the dog ( Canis familiaris) was investigated by histological and microelectrode technique. The LCN extends from the obex to the upper C3 and is located ventrolateral to the dorsal horn. Cell counts showed over 6,000 cells in the nuclei on both sides and the cell size varied from 20 to 45 µ. Single-unit analysis of the 220 neurons showed that the majority of cells responded to touch, some to pressure, some to pressure and touch, and an extremely limited number to joint movement. All responses were recorded from the ipsilateral half of the body. More than half of these neurons had small peripheral receptive fields located mostly in the distal parts of the limbs. The rest, with large receptive fields, were located mainly in the proximal parts of the limbs and the trunk. The peripheral receptive fields were almost equally distributed among the forelimb, trunk, and hindlimb for touch. The prominence of the hindlimb representation over the forelimb was found for pressure and for touch and pressure. The results indicate that the organization of the afferent input to the LCN has some similarity to that of the medial lemniscus system.
Effect of vasopressin infusion and sciatic nerve stimulation in isolated dog hindlimb
Authors: Diana John N. , Masden Ronald R.
Published: December 2017

Measurements of changes in peripheral venous pressure in digital and muscle veins, arterial pressure, leg weight, and venous outflow were made under conditions of constant arterial inflow during vasopressin infusion into the isolated dog hindlimb. Evidence is given to show that vasopressin exerts a constrictor effect on the peripheral veins of the dog and that this constrictor activity is present after adrenergic blockade with phenoxybenzamine and after norepinephrine depletion with reserpine. It is also shown that exogenous levarterenol can cause additional vascular constrictor activity after a maximum pressor response has been obtained with vasopressin, thus demonstrating either separate sites of action for the different hormones or a limiting action to the excitatory activity of vasopressin by the same effector cell. Peripheral vascular refractoriness to subsequent doses of vasopressin can be decreased by sciatic nerve stimulation and the decrease in refractoriness is more pronounced if stimulation is performed after administration of levarterenol.
Dietary production and dissolution of cholesterol gallstones in the mouse
Authors: Caldwell Fred T. , Levitsky Katherine , Rosenberg Barbara
Published: December 2017

Groups of animals fed lithogenic diets were sacrificed at intervals, with serum and bladder bile obtained. Bile was analyzed for bile acids, lecithin, free fatty acids, and cholesterol concentrations, serum for cholesterol and free fatty acids. Gall bladders were also examined for histological change. The chemical response to the diets was a prompt increment in serum and bile cholesterol concentrations. After an initial rise, bile acid content of bile decreased, resulting in a fall in bile acid-to-cholesterol ratios to the point of cholesterol precipitation. Stones once formed dissolved when animals harboring stones were fed Purina laboratory chow. Histological changes appeared in the gall bladder after 2 weeks on the diets and were progressive.
Systolic pressure gradients across the aortic valve and in the ascending aorta
Authors: Driscol Thomas E. , Eckstein Richard W.
Published: December 2017

Left ventricular and aortic pressure pulses and the pressure gradient across the aortic valve were recorded in anesthetized and unanesthetized dogs. Aortic pressure recorded immediately above the valve increased 5–15 msec before it was exceeded by left ventricular pressure. The maximum systolic pressure gradient occurred in early systole and remained positive throughout the ejection period. When aortic pressure was recorded 1–3 cm distal to the valve, these pressure pulse relationships were altered so that 1) the rise in aortic pressure was delayed, 2) the early systolic maximum pressure gradient was increased, and 3) aortic pressure exceeded ventricular pressure during the latter half of systole. The changes in early systole are due to a delay in the pulse wave reaching the more distal recording site. The mean systolic pressure gradient between two sites within the ascend-ing aorta was found to be negative, i.e., opposite to the direction of forward flow. The negative pressure gradient probably accounts for the reversal of the transvalvular pressure gradient in late systole when aortic pressure was recorded distal to the valve.
Effect of hemoglobin type on the cardiorespiratory system of sheep
Authors: Dawson T. J. , Evans J. V.
Published: December 2017

In domestic sheep there exist two genetically determined types of hemoglobin which have considerably different oxygen affinities. Under most conditions sheep with either of these hemoglobins exist together, apparently sheep with one type being at no gross disadvantage compared to those with the other. Theoretical considerations suggested that the tissues of sheep with the higher oxygen affinity hemoglobin (Hb-A) should be hypoxic relative to those of sheep with the lower oxygen affinity hemoglobin (Hb-B). The data obtained showed that the cardiovascular and respiratory systems of animals with different hemoglobins differed in many respects. It was concluded that the nature of these differences was such that they could be viewed as being due to adjustments by animals with Hb-A to alleviate the potential hypoxia of their tissues relative to the tissues of animals with Hb-B.
Effects of prolonged centrifugation on growth and organ development of rats
Authors: Oyama Jiro , Platt William T.
Published: December 2017

Mature and weanling Sprague-Dawley female rats were centrifuged at 2.5, 3.5, and 4.7 g for periods of time ranging up to 1 year. The growth rates and final body weights of weanling rats were significantly lower than those of noncentrifuged control rats. Both mature and weanling rats experienced initially a temporary loss in body weight due to inanition and reduced food consumption. Comparison of organ-to-body weight ratios of 4.5-month and 1-year centrifuged rats with corresponding control rats indicated that prolonged exposures caused only a few changes. Relative weights of the adrenals of 4.5-month centrifuged rats were reduced, whereas the livers of 1-year centrifuged rats were increased. There was an apparent decrease in red blood cells and a significant decrease in hematocrit values of centrifuged rats. No histopathology was found in any of the centrifuged groups of rats which could be attributed to the exposure treatment. Results of this study show that rats are able to tolerate prolonged periods of simulated high-gravity environments with little, if any, serious deleterious effects.
Some effects of autologous and homologous blood or plasma overtransfusions in the dog
Authors: Huggins R. A. , Smith E. L. , Deavers S.
Published: December 2017

Plasma volume, protein concentration, mean arterial pressure, urticaria, and survival rates were observed in morphine-pentobarbitalized dogs overtransfused with either dextran, homologous blood, reconstituted homologous blood, autologous frozen stored, homologous frozen stored, or fresh plasma. The principal reaction and only difference between responses with autologous plasma and homologous blood and plasma was the development of urticaria with homologous blood (10%), homologous plasma (70–90%), and reconstituted homologous blood (100%). Significant amounts of fluid and protein were lost with all overtransfusions; this loss was not correlated with the urticaria. Of five dogs developing urticaria, three had an increased plasma histamine level. Diphenhydramine hydrochloride reduced the incidence of urticaria from 100 to 20%. Blood group incompatibility was not involved. There was a direct relationship between handling of blood and urticaria, and it is postulated that, during handling, a substance is activated which causes the release of endogenous histamine and production of urticaria.
Krypton 85 myocardial blood flow: precordial scintillation versus coronary sinus sampling
Authors: Klein Michael D. , Cohen Lawrence S. , Gorlin Richard
Published: December 2017

Myocardial blood flow in human subjects was assessed by comparative simultaneous measurement of krypton 85 radioactive decay from coronary sinus and precordial scintillation. Empirical correction of postclearance background from precordial curves yielded a high degree of correlation between flows derived from the two sampling sites (r = .889, P < .001). Comparison of left and right coronary flows in nine subjects revealed similarity in flow through the two vessels over a wide range of actual flow values (r = .945, P < .001).
Tissue lactic dehydrogenase isozymes: variation in rats during prolonged cold exposure
Authors: Blatt William F. , Walker John , Mager Milton
Published: December 2017

Total lactic dehydrogenase (LDH) activity as well as the relative distribution of heart- and muscle-type subunits was assayed in tissues of rats chronically exposed to cold (6 weeks, 5 C). A depression of LDH activity was noted in heart and liver following 1 week at 5 C; restoration to normal levels occurred in weeks 2, 3, and 4 which persisted for heart tissue; liver values fell below normal limits for the final 2 weeks of study. No significant changes in total activity or in subunit distribution were seen in kidney, muscle, plasma, or red blood cells. A progressive increase in the ratio of heart to muscle type was noted in heart muscle with a final level almost twice that of the control value. The changes in total activity as well as the relative distribution of the subunits may be related to substrate availability, tissue oxygen supply, or hormone action; the study did not permit assessment of any of these parameters as the causative factors. The adaptive change observed in heart muscle affords a possible example of the modification of genic expression by environmental stress.
Corticosteroids for reversal of hemorrhagic shock in rats
Authors: Weil Max Harry , Whigham Howard
Published: December 2017

Corticosteroids administered in amounts more than 100 times those required to sustain a fully adrenalectomized animal were highly effective in increasing survival following hemorrhagic shock. In rats with intact adrenal glands, hemorrhagic shock was produced by maintaining arterial blood pressure at 35 mm Hg for 240 min. Glucocorticoids and aldosterone were administered only after blood was reinfused. The therapeutic benefit is due to a pharmacological action of the adrenocortical hormone. Aldosterone had a lesser and relatively narrow dosage range of effectiveness.
Uterine response to nerve stimulation; relation to hormonal status and catecholamines
Authors: Miller Mary D. , Marshall Jean M.
Published: December 2017

Immature Dutch rabbits were treated as follows: group 1, 70 µg estradiol-17ß every other day for 4 days; group 2, 70 µg estradiol-17ß every other day for 4 days, then 5 mg progesterone daily for 5 days; group 3, untreated controls. Uterine muscles with their hypogastric nerves attached were isolated, and the responses of the uterus to hypogastric nerve stimulation were recorded. Nerve stimulation (5–50 pulses/sec) contracted uteri from untreated and estrogen-treated rabbits. Nerve stimulation inhibited the spontaneous contractions of estrogen + progesterone-treated animals. These effects were unchanged by atropine or hexamethonium but were abolished by the adrenergic blocking agents phentolamine (estrogen-treated uteri) and propranolol (estrogen + progesterone-treated uteri). Uterine catecholamine content was unaltered by hormonal treatment. Pretreatment with reserpine greatly diminished uterine catecholamine content as well as the response to nerve stimulation in all animals. The hypogastric nerves therefore contain predominantly postganglionic adrenergic fibers, and the effects of their stimulation on uterine activity depend on the hormonal status of the myometrium.
Electromyography of chickens with inherited muscular dystrophy
Authors: Holliday T. A. , Van Meter J. R. , Julian L. M. , Asmundson V. S.
Published: December 2017

In affected muscles of dystrophic chickens, electromyography with needle electrodes revealed hyperexcitability to mechanical stimuli such as electrode movement (prolonged "insertion activity"), spontaneous potentials, and polyphasic motor unit potentials. In agreement with pathological findings in this and previous studies, the light breast muscles exhibited more extensive electromyographic abnormalities than the more distally placed light muscles of the wings, whereas the dark muscles of the legs showed little or no electromyographic abnormality. Electrode movement in the muscles of 5-day-old chickens evoked a discharge of high-frequency, low-amplitude potentials which continued for several seconds. In normal chickens the duration of this discharge diminished with age and reached the adult level, 1 sec, at 30 days of age. Breast muscles of dystrophic chickens first exhibited distinct electromyographic abnormalities at I6 days of age. It is possible that onset occurred earlier but was obscured by the high-frequency discharges normally observed during this period of life.
Physiologic and electrocardiographic correlations in experimental left heart failure
Authors: Salisbury Peter F. , Cross Cecil E. , Rieben P. Andre , Sodi-Pallares Demetrio
Published: December 2017

Left ventricular failure was reproduced in dogs with open chest and closed pericardium in two ways: a) by overloading the heart, the resulting rise of LVDP being manifested electrocardiographically by evidence of injury to the subepicardial layers of LV wall: the elevations of R-ST segments being proportional to the magnitude of LVDP. This type of heart failure was not considered to leave residual injury because coronary flow and myocardial oxygen consumption returned to normal when the work of the heart was returned to control levels; b) by decreasing the perfusion pressure in the left coronary tree, the ECG revealing consecutive states of subendocardial ischemia, subendocardial injury, subendocardial injury plus subepicardial ischemia, and subepicardial injury. This typical ECG sequence changed simultaneously with increases of LVDP and of the acidity of coronary venous blood. After periods of "coronary insufficiency," physiologic, but not electrocardiographic, variables remained abnormal for prolonged periods.
Effect of epinephrine on stress relaxation and distensibility of the isolated cat heart
Authors: Leach John K. , Alexander Robert S.
Published: December 2017

To investigate the cause of the rapid relaxation observed in the epinephrine-stimulated heart, stress relaxation and distensibility have been measured in the isolated perfused cat heart and in isolated papillary muscles. During epinephrine stimulation, distensibility was slightly increased but there was no change in the rate of stress relaxation. This would suggest that the action of epinephrine is confined to the contractile elements without any direct effect on the viscoelastic elements responsible for stress relaxation. The rapid diastolic relaxation observed in these hearts therefore relates to the dynamics of the contraction process rather than to lowered myocardial viscosity.
Carbon dioxide dissociation curve and buffer capacity of dog heart muscle
Authors: Benson E. S. , Freier Esther F. , Vijums Regina
Published: December 2017

The carbon dioxide dissociation curve of dog heart muscle was found to be higher than of dog skeletal muscle. The slope of this dissociation curve in the range of Pco2 20–55 and the buffer capacity of dog heart muscle with respect to Pco2 appear to be approximately equal to those of dog skeletal muscle. Seemingly, in the dog, heart muscle is at least as well buffered against the pH-lowering effect of increasing CO2 tension as is skeletal muscle and is more effectively buffered than has previously been realized.
Determination of CRF activity in rats treated with Monase, dexamethasone, and morphine
Authors: Schally Andrew V. , Carter Weldon H. , Hearn Ina C. , Bowers Cyril Y.
Published: December 2017

The effects of Monase (3-(2-aminobutyl)-indole acetate) on adrenocortical function were studied in rats with the aim of developing a new assay for corticotropin-releasing (CRF) activity. Administration of Monase and Nembutal led, after a 3-hr period, to inhibition of the increase in plasma levels of corticosterone which normally follows the stress of injection into jugular vein and laparotomy. Monase does not interfere with formation and secretion of corticosterone, but acts by suppressing secretion of ACTH. Monase inhibited the increased corticosterone secretion normally produced by administration of 5–15 mU of lysine vasopressin, 50 µg histamine, and 5 µg epinephrine, but did not block the response to 500 µg histamine or 30 mU vasopressin. Peptides such as lysine and arginine vasopressin, "natural" dimer of lysine vasopressin, angiotensin II, and α1- and ß-CRF were tested at several dose levels in groups of rats treated with morphine-Nembutal, dexamethasone-Nembutal, or Monase-Nembutal, and the responses are reported.
Relationship of current parameters to hyperpnea produced by brain polarization
Authors: Davies Richard O. , Yamamoto William S.
Published: December 2017

The phenomenon of synchronized hyperpnea, produced by applying biased sinusoidal currents to a circumscribed area of the rat brain stem, was characterized in terms of some stimulus parameters. Ventilation was increased when the amplitude of the sinusoidal component was increased; at 1 cycle/sec and negative bias, V = 851 + 123. The magnitude of the hyperpnea was frequently dependent. Of the frequencies tested (0, 1, 2, 3, and 4 cycles/sec), a stimulus of 2 cycles/sec elicited the largest ventilatory response. In the absence of a sinusoidal component, the effect of cathodal current on ventilation was given by the equation V = .421 + 134. As an anode, the electrode exerted no significant effect on ventilation.
Ion transport in isolated cornea of the rabbit
Authors: Green K.
Published: December 2017

When the isolated rabbit cornea is bathed with well-stirred normal Ringer solution, only a low potential difference (PD) exists across the tissue; the initial value of 2 mv rises to 6 mv (endothelium positive) 1 hr after excision from the animal. In sodium-free Ringer solution the PD becomes negative before becoming negligible, while in chloride-free Ringer the PD rises to triple the value in normal Ringer. Flux measurements of sodium 22 show that there is an initial inequality between the net flux and the measured short-circuit current (SCC), the values of which become equal 1 hr after removal of the cornea from the animal Flux measurements of chloride 36 during this 1st hr indicate an active transport of chloride inward across the cornea, but after 1 hr the fluxes are equal in each direction. The differences of the net currents generated by the sodium and chloride transports equal the measured SCC, and the two transports have been shown to be able to exist independently.
Transmitter release and vascular responses in skin and muscle of hypertensive dogs
Authors: Zimmerman et al. B. G.
Published: December 2017

Page 798: B. G. Zimmerman et al., "Transmitter release and vascular responses in skin and muscle of hypertensive dogs." Page 801: the values of 9.1 and 12.9 cm2 for the areas of the vasoconstrictor responses in Table 3 were indicated previously as not being significantly different. These values differ significantly at the P < 0.05 level.
Effects of cardiac tamponade on myocardial performance, blood flow, and metabolism
Authors: Frank M. J. , Nadimi M. , Lesniak L. J. , Hilmi K. I. , Levinson G. E.
Published: December 2017

Page 179: M. J. Frank, M. Nadimi, L. J. Lesniak, K. I. Hilmi, and G. E. Levinson. "Effects of cardiac tamponade on myocardial performance, blood flow, and metabolism." Page 183, legend to Fig. 3 should read, "Effect of cardiac tamponade on left ventricular performance." Page 183, legend to Fig. 4 should read, "Effect of caval obstruction on myocardial contractility. Abbreviations as in Fig. 2. MRPR and end-diastolic fiber length are significantly reduced, while MIP is unchanged. Contractility is same as that during control state."
Natriuretic effects of vaso-pressin and cyclic AMP: possible site of action in the nephron
Authors: Martinez-Maldonado M. , Eknoyan G. , Suki W. N.
Published: December 2017

Page 2013: M. Martinez-Maldonado, G. Eknoyan, and W. N. Suki. "Natriuretic effects of vaso-pressin and cyclic AMP: possible site of action in the nephron." Page 2016, the second sentence of the legend to Fig. 4 should read, "Control kidney (◯); experimental kidney (○)." Page 2018, Table 6, Dog I, last column: on line 20, the value 705 should read 205; on line 21, the value 703 should read 203.
Pressure-flow relations in the vessels of the canine aortic arch
Authors: Cox RH , Pace JB
Published: December 2017

Simultaneous measurements of pressure and flow have been made in the vessels of the aortic arch in chloralose-anesthetized dogs under three conditions; control, cardiac sympathetic (SS), and vagal nerve stimulation (VS). The specific sites studied include ascending aorta (AA), descending thoracic aorta (DTA), and brachiocephalic (BCA), left subclavian (LSC), and common carotid arteries (CA). Recorded data were analyzed by Fourier series methods and were used to calculate vascular impedance spectra, pressure and flow propagation characteristics, and hydraulic power. The distribution of cardiac output was found to be 70% to DTA, 22.2% to BCA, and 6.5% to LSC. The fraction of cardiac output to the BCA, LSC, and CA was increased by both SS and VS. The hydraulic power was distributed to the arch vessels nearly the same as the cardiac output. Hydraulic power dissipated in the arch vessels averaged 6% of the total AA hydraulic power and was increased by SS and decreased by VS. The results suggest that viscous losses in the arterial walls represent a considerable portion of the power dissipation. A similarity found in the vascular impedance spectra at the various sites for all three conditions was also observed for the transmission characteristics of pressure and flow harmonics between the sites. The results suggest that major reflections do not occur in the proximal aorta.
Effect of age on transvascular fluid movement
Authors: Rosenthal SM , LaJohn LA
Published: December 2017

Swellings of the mouse tail and ear were produced by subjecting them to subatmospheric pressures of minus 40 to minus 80 mmHg for 15-60 min. Increase in volume was measured volumetrically in the tail and gravimetrically in the ear. Blood volume increases in the tail, as measured with 51Cr erythrocytes, contributed a minor part of the fluid increase. Comparison of mice from 3 to 36 wk in age showed a large decrease of fluid movement with age, with major changes during the growth period. Study of permeability of the ear under decreased pressure,to intravenously administred Evans blue, showed no influence of age on permeability to the protein-bound dye. Measurement of transmission of the applied negative pressure through the skin, and of compliance of the tissues of the ear and tail in mice of different age groups, indicated that these factors were not responsible for the observed changes with age.
Localized myocardial responses to stimulation of small cardiac branches of the vagus
Authors: Armour JA , Randall WC , Sinha S
Published: December 2017

Direct electrical excitation of small cardiac branches from the thoracic vagus elicited highly localized and differential responses from individualized segments of the myocardium. For example, small nerves from the vagus at the level of the superior pulmonary veins frequently induced moderate inhibition in contractile force of the ipsilateral atrium with little or no influences elsewhere. Branches from more rostral levels of the thoracic vagus induced changes in atrial contractility, with or without changes in sinoauricular (SA) nodal discharge rates, and often with partial or complete artioventricular (AV) nodal blockade.Excitation of individual, small vagal branches sometimes initiated acceleration in artrial rate and augmentation in atrial contractile force concurrently with complete AV nodal blockade. The negative dromotropic response was eliminated by atropine, leaving only the positive chronotropic and inotropic changes, thus revealing the intermingling of both sympathetic and parasympathetic components even in these small branches. There are frequently in excess of 20 small branches from the vagal trunk between the level of the caudal cervical ganglion and the superior pulmonary vein on each side which will induce highly selective changes in cardiac function upon stimulation. Inhibitory branches are particularly concentrated in the region of the recurrent laryngeal nerve on either side.
Vasopressin release during nonhypotensive hemorrhage and angiotensin II infusion
Authors: Shade RE , Share L
Published: December 2017

These experiments were designed to determine whether angiotensin II (AII) could potentiate the increase in plasma vasopressin (ADH) concentration produced by continuous, nonhypotensive hemorrhage in nephrectomized dogs. Infusion of AII (10 ng/kg.min) into a common carotid artery in nonbled dogs did not increase plasma ADH levels, suggesting that increases in carotid arterial plasma AII concentration alone do not stimulate an increase in ADH release. Subsequently, nephrectomized dogs subjected to nonhypotensive hemorrhage (0.44 ml/kg.min) were infused as follows: 0.9% saline intravenously, AII (10 ng/kg.min) intravenously, or AII (10 ng/kg.min) into the carotid. The Plasma ADH concentration increased in all three groups of dogs during hemorrhage. Although the AII-infused dogs demonstrated significant increases in plasma ADH levels earlier during hemorrhage, these changes were small; there were no statistically significant differences in plasma ADH concentrations among the three groups. These results suggest that increases in plasma AII concentration have little or no significant effect on the volume control of ADH release.
Comparison of transport mechanisms in isolated ascending and descending rat colon
Authors: Yau WM , Makhlouf GM
Published: December 2017

The mechanisms of water and ion transport in ascending and descending rat colon were compared using an everted open mucosal sac preparation. Net water flux, measured gravimetrically, was similar in both segments (15.3 plus or minus 1.2 and 13.7 plus or minus 1.3mul h(-1) mg(-1), NS). Net catonic flux J(Na+K),net anionic flux J(Cl-HCO3), and net solute flux Josm were also similar; but the constituents of these flux , namely JNA, JK, and JHCO3, were significantly different. The descending colon absorbed significantly less Na and secreted significantly more HCO3. Only the descending colon absorbed K, whereas net JK across the ascending colon was zero. The PD across either segment ranged from 3 to 7 mV, mucosal side negative. Consideration of net flux and electrochemical gradient indicated that in both segments Na was absorbed actively. The nature of Cl transport could not be ascertained. Assuming transmural movement, HCO3 was secreted (or H ion absorbed) actively. Only the descending colon absorbed K actively. Across the ascending colon K was distributed close to electrochemical equilibrium.The compostion of the absorbates was calculated from Ji/Jv after correction of Jv for filtered water. Both absorbates were equally hypertonic (448.5 plus orminus 9.3 and 421.7 plus or minus 13.2; NS.)The ascending colon absorbate contained a significantly higher Na concentration and no K. The descending colon absorbate contained 15 mM K, about 3 times the K concentration in the bathing solution. It was concluded that the ascending colon and descending colon displayed quantitative differences in Na absorption and HCO3 secretion and a qualitative difference in K transport.
Ferritin and intestinal iron absorption: pancreatic enzymes and free iron
Authors: Linder MC , Dunn V , Isaacs E , Jones D , Lim S , Van Volkom M , Munro HN
Published: December 2017

Rat intestinal mucosa gave low yields of ferritin purified by standard procedures. The resulting ferritin had less protein relative to iron and migrated faster electrophoretically than ferritin from other rat tissues. Pancreatic duct ligation reduced these differences, suggesting digestive enzyme attack during ferritin isolation. Even in ligated rats, ferritin accounted for only 5-10% of mucosal iron. However, shortly after giving 59FeCl3 orally, 50% of mucosal radioactivity occurred in cell sap, about equally distributed between ferritin and low-molecular-weight (chelated?) iron. No other cell sap components were 59Fe labeled. Iron may thus be transported as a chelate with which ferritin is in rapid equilibrium. Mucosal ferritin content increased with age and iron treatment and decreased with iron deficiency. The iron-deficient rats showed accelerated 59Fe uptake into blood with little mucosal retention. One day after administering parenteral iron to deficient rats, 59Fe transfer to blood became retarded but 59Fe now accumulated excessively in the mucosa, suggesting that iron status affects transport more rapidly at the serosal than at the mucosal cell surface. A scheme for control of iron absorption is presented.