bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of vasopressin structural modifications on rat renal excretion of Na, K, and water
Authors: Barnafi L. , Rosas R. , Pereda T. , Croxatto H.
Published: December 2017

Lys8-vasopressin was incubated with trypsin, chymotrypsin, and sodium thioglycollate, and the resultant modification of the effect of the hormone on sodium, potassium, and water excretion was studied. These agents, which destroy the antidiuretic-pressor activity of the hormone, also bring about a loss of its natriuretic and kaliuretic effects. The action of Arg8-vasopressin, Phe2-Lys8-vasopressin, and His2-Lys8-vasopressin on sodium, potassium, and water excretion was studied; comparisons were made with the effects of equivalent pressor doses of Lys8-vasopressin. No significant differences between Arg8- and Lys8-vasopressin were obtained. Phe2-Lys8-vasopressin had nearly ten times the antidiuretic effect and four times the natriuretic and kaliuretic effect. Even though His2-Lys8-vasopressin has an antidiuretic effect, it lacks activity with regard to blood pressure or electrolyte excretion.
Effect of temperature and ouabain on resting tension and Ca45 entry in rabbit atria
Authors: Briggs Arthur H. , Holland William C.
Published: December 2017

The effect of temperature on the action of ouabain on resting tension and Ca45 entry in isolated quiescent and stimulated left atria from rabbits was measured. In quiescent preparations a change of temperature from 27 C to 37 C did not affect Ca entry or resting tension. At 27 C ouabain increased Ca influx and resting tension when compared with either quiescent or stimulated atria. A 10 C increase in temperature enhanced the effect of stimulation and ouabain. The estimated Q10 values for the action of ouabain on Ca entry and resting tension were 6.6 and 4.2, respectively. It was concluded that, since the Q10 values for the effect of ouabain on resting tension and Ca entry are much greater than for Ca entry in quiescent nontreated preparations, ouabain affects a Ca transport mechanism distinctly different from that responsible for resting exchange. The former mechanism is probably related to the excitation contraction coupling system in the myocardium.
Vascular volume and blood level of antidiuretic hormone
Authors: Share Leonard
Published: December 2017

The role of vascular volume in regulation of the blood level of antidiuretic hormone (ADH) was investigated utilizing a chemical procedure for extraction, isolation, and concentration of ADH in blood. The antidiuretic material recovered from blood was identified as ADH on the basis of its biological activity and the results of a number of chemical tests. Reduction in extracellular fluid volume by peritoneal lavage with hypertonic solution produced a fourfold increase in the blood titer of ADH within 20 min. Expansion of vascular volume at that time by the intravenous infusion of isotonic dextran solution resulted in a 50% reduction in the blood level of ADH. This reduction was maintained for the 30-min period of observation, although the blood level of ADH rose progressively when the lavage procedure was uninterrupted by infusion of dextran solution. It is concluded that blood volume is an important factor in regulation of blood concentration of ADH.
Effect of iproniazid on metabolism of noradrenaline in man
Authors: Rosen Lawrence , Goodall McC.
Published: December 2017

Adult males were infused with dl-noradrenaline-2-C14 and the radioactive urinary catabolites were analyzed. At the end of 24 hr, 78% of the infused dose was recovered. The recovered urinary radioactivity was distributed as follows: noradrenaline, 5%; 3-O-methylnoradrenaline, 5%; 3-O-methylnoradrenaline sulfate, 19%; 3-methoxy-4-hydroxymandelic acid, 36%. The remaining radioactivity was distributed among other catabolites, known and unknown; these catabolites have been described. After treatment with iproniazid, the distribution of the urinary radioactivity between the two major catabolites, 3-O-methylnoradrenaline sulfate and 3-methoxy-4-hydroxymandelic acid, was significantly altered. For the 24-hr period, 3-O-methylnoradrenaline sulfate was greatly increased and accounted for 46% of the total radioactivity recovered; conversely, 3-methoxy-4-hydroxymandelic acid was greatly decreased and accounted for only 10% of the total radioactivity recovered. Significant increases were also noted for noradrenaline and 3-O-methylnoradrenaline during the first 6 hr. These results demonstrate that iproniazid alters the metabolism of noradrenaline by inhibiting the action of monoamine oxidase. The neutral and acidic catabolites have been described. Vanillic acid has been identified as a metabolite of noradrenaline.
Partial analysis of segmental resistances in intestinal vessels after endotoxin
Authors: Meyer Maurice W. , Visscher Maurice B.
Published: December 2017

Hemodynamic responses of intestinal vascular segments of the dog to intravenous administration of a lethal dose (1 mg/kg) of E. coli endotoxin were investigated. Pressures were measured in large and small vessels of the intestinal and mesentery (small veins 30–60 µ in radius). Vascular radii of submucosal vessels and blood flow were determined. Changes in total resistance in the intestinal circulation after endotoxin were not uniform during the first few minutes, but there was a significant decrease at 10 min and a subsequent rise to the control value after 1 hr. At both 50 and 60 min, the resistance was increased over control in the arterial segment by 50%, increased 500% in the venous segment, and decreased 40% in the segment from small artery to venule. These circumstances would increase capillary pressure and filtration of edema fluid. Increased wall tension at reduced diameter developed in the venous segment during the secondary shock state, whereas relaxation of wall tension occurred in the arteriolar segment.
Behavior of radiozinc in rat plasma
Authors: Okunewick J. P. , Pond B. , Hennessy T. G.
Published: December 2017

This series of studies was undertaken to determine the behavior of Zn65 when injected intravenously as the inorganic ion. A clearance curve for Zn65 similar to those of other workers was obtained. It was found that the decrease in clearance and distribution of Zn65 was not in direct proportion to the decrease in specific activity. Upon extraction of loosely bound zinc from plasma with dithizone-acetone virtually all of the injected Zn65 could be removed up to 1 hr after intravenous injection. However, extraction of the unbound zinc ion demonstrated that more than 90% of the Zn65 is bound to protein within the first 3 min after addition of Zn65. Dialysis of Zn65 against plasma protein showed the Zn65 ion is removed by plasma from solution by direct binding to nondialyzable plasma components. Irradiation of rats with supralethal dosages of X ray followed by subsequent injection of Zn65 demonstrated that clearance of Zn65 from plasma is unaffected by this major alteration of the metabolic state of the animal.
Hydrostatic pressure on vagal effects and heart contraction
Authors: Young Wei , Upham Frank
Published: December 2017

Vagal inhibitory effects are readily observed in isolated vagal heart preparations of Rana pipiens. The normal effect was partially blocked by raising the hydrostatic pressure to about 2,000 psi. There was a complete block of vagal effects at about 5,000 psi or more. When the preparation was subjected to low pressure, the vagal inhibitory effect again occurred. This process could be repeated several times. Physostigmine raised the critical pressure limit by about 2,000 psi. The observed phenomena are discussed in particular with respect to the kinetics of acetylcholinesterase under the high pressure. Work done per contraction of the heart is increased under high pressure by about 25%. The total work done, however, in a definite period, e.g., 1 min, is decreased because the rate of the contraction is decreased.
Renal and hepatic excretions of phenol red and Bromsulphalein in the dog
Authors: Woo Tai Ha , Hong Suk Ki
Published: December 2017

Effects of acetate, 2,4-dinitrophenol (DNP), Diodrast, dehydrocholic acid, and Na taurocholate on the urinary and biliary excretions of phenol red (PSP) and Bromsulphalein (BSP) were studied in 36 anesthetized dogs. Acetate increased the urinary excretion of both dyes as well as the biliary excretion of PSP whereas it had no effect on the biliary excretion of BSP. 2,4-DNP suppressed the urinary excretion of both dyes while it greatly increased the biliary excretion of PSP which was accompanied by an increase in the bile flow. However, the biliary excretion of BSP was increased only slightly by 2,4-DNP even though bile flow increased greatly. Diodrast, dehydrocholic acid, and Na taurocholate uniformly reduced both urinary and biliary excretions of PSP and BSP. Although some of these effects could be related to a corresponding change in bile flow, there was no consistent parallelism between the changes in dye excretion and in urine or bile flow. On the basis of these results, it is postulated that both the kidney and liver secrete PSP and BSP through a similar transport system. The energy dependence of this system could not be clearly ascertained from the present study.
Control of bile flow in the cholecystectomized dog
Authors: Fritz Michael E. , Brooks Frank P.
Published: December 2017

Rate of flow and composition of bile were measured in three unanesthetized, cholecystectomized dogs. One of these animals and one other dog were also studied after bilateral vagotomy. Bile flow and output of solids were increased by intravenous insulin and feeding. Tolbutamide had a similar choleretic effect. The anticholinergic drug, pipenzolate methylbromide blocked the choleretic effect of insulin. After bilateral vagotomy, the choleretic effect of both feeding and insulin-hypoglycemia was lost. Commercial pancreozymin had a choleretic action which may indicate a role of intestinal hormones in the response to feeding. Intraduodenal injection of hydrochloric acid was followed by an increase in only the volume of bile. Glucagon produced a hydrochloresis and an increase in bilirubin output. The results suggest that normal bile production in the dog after eating may be controlled in part by a mechanism involving the vagus nerves. The data also show that the insulin-hypoglycemia-induced choleresis differs from that of secretin. The composition of hepatic bile obtained from the common duct is consistent with an absorptive function of the ductal epithelium in the dog without a gallbladder.
Electrical parameters of smooth muscle cells
Authors: Nagai T. , Prosser C. L.
Published: December 2017

Spikes in circular intestinal muscle fibers show volume-conductor shapes and conduct faster in low resistance medium than in air. Longitudinal space constant is 1.0 mm (20 cell lengths if 50% overlap); transverse space constant is 0.27 mm or 50 cell widths. The membrane time constant measured intracellularly is 31 msec, between two cells by double microelectrodes 7 msec. Cell membrane resistance is 70 megohms, between two cells 17 megohms, cell capacitance 4.5 x 10–4µf. For a surface area of 8 x 10–6 cm2, membrane resistance is 560 ohms cm2, capacitance 56 µf/cm2; because of surface folding and intercellular shunting, specific resistance is probably higher and capacitance lower. Membrane resistance in longitudinal muscle is two-thirds that in circular. Interfiber resistance rises, extracellular space increases, and velocity decreases in hypertonic solutions. Voltage-current curves show normal rectification. Depolarizing or polarizing pulses initiate 24/sec oscillations; depolarization can cause instability and spikes. Amplitude of conducted spikes is reduced by both depolarization and hyperpolarization. No change in membrane resistance occurs during a spike, probably because of parallel conducting fibers in different planes. Interfiber membranes are nonreactive, show no oscillations and no rectification, are of lower resistance than normally reactive membranes, and may represent labile zones of contact. Threshold current is about 0.2 x 10–9 amp which corresponds to that normally crossing the relatively low-resistance interfiber junctions.
Electrolyte changes in blood, urine, and tissues after lipid and other test meals
Authors: Swank Roy L. , Jackson Lavelle
Published: December 2017

Hamsters were fed large (8 g/kg) test meals of cream, cod liver oil, carbohydrate, and protein and the Ca, Na, and K levels in red blood cells, serum, urine, and tissues were determined. 1) Urinary changes consisted of a decrease in Ca and Na 4–7 hr after both cream and cod liver oil meals. These changes were most marked after cream. Potassium excretion also decreased after cod liver oil meals, but increased after cream meals. 2) Seven hours after lipid meals both Ca and K were decreased in red blood cells. At the same time Ca and Na decreased in serum after cod liver oil meals, and the K initially increased after both lipid meals. 3) Cation changes in the heart 7 hr after feeding consisted of a reduction in Ca and Na, and a possible increase in K after cream. These changes did not occur after test meals of water, protein, carbohydrate, or cod liver oil. 4) In the brain, Ca, Na, and K were all decreased 7 hr after cream meals, and increased by all other meals. 5) Significant dehydration of all tissues was present 7 hr after cream meals. This was not observed after any other test meals.
Enhancement of renal concentrating ability in the dog by urea and related compounds
Authors: Rabinowitz Lawrence , Kellogg Ralph H.
Published: December 2017

Experiments were performed on vasopressin-infused dogs to test the effect on renal concentrating ability of acute administration of urea and seven other organic nonelectrolytes. In each experiment a control assessment of concentrating ability was obtained during administration of mannitol. This was followed by administration of a test compound in an amount designed to maintain the previous rate of solute excretion. When compared to control values, urine osmolality was significantly higher during administration of urea, methylurea, acetamide, 1,2-propanediol and 1,3-dimethylurea, but not during administration of thiourea, glycerol, or hexamethylenetetramine. Others have suggested that the enhancement of concentrating ability by urea is related to the unique ability of urea to diffuse through the collecting-duct membranes. In the present study, there appeared to be no simple correspondence between the degree to which urine osmolality increased and the physical properties generally recognized to affect membrane permeation: oil:water partition coefficient, molecular size, or specific chemical groups.
Utilization of glucose by the hypothermic rat
Authors: Fuhrman Geraldine J. , Fuhrman Frederick A.
Published: December 2017

Hyperglycemia of several hours duration was shown to occur in fasted rats given a small glucose load at a body temperature of 18 C. To eliminate the possibility that continued formation of glucose from glycogen produced the hyperglycemia, carbohydrate balance studies were made. The glycogen in the livers of cooled rats was the same with and without a glucose load, indicating a failure in ability to store glycogen. After injection of C14-labeled glucose into hypothermic rats, the specific activity of glucose in the plasma remained constant for 2 1/2 hr. This is further evidence that endogenous glucose is not added to the extracellular phase during hypothermia. The rate of uptake of glucose by muscle was measured at 38 and 18 C, and these results compared with those obtained in the whole animal. Removal of glucose from the blood is far slower than expected from physical chemical effects of temperature. Failure to convert glucose to glycogen may be the cause of the hyperglycemia in hypothermia.
Increased aldosterone secretion by tumor-bearing rats
Authors: Millar Florence K. , Toal Jane Nicolet , Brooks Robin H. , Davis James O. , White Julius
Published: December 2017

Sprague-Dawley rats, bearing the Walker carcinosarcoma 256 subcutaneously, retain more of their daily sodium intake than do normal (nontumor-bearing) growing rats. In the present study, secretion of aldosterone and corticosterone has been determined in 16 such tumor-bearing rats and in 8 normal controls. The left renal vein was cannulated and effluent blood from the left adrenal collected. Blood flow rate and hematocrit were measured. Aldosterone and corticosterone were determined in the collected plasma by the double-isotope derivative method. Aldosterone secretion rate and concentration in effluent plasma, effluent plasma flow rate, adrenal size, and width of the zona glomerulosa were all significantly higher in the tumor-bearing group than in the normal. Aldosterone secretion rate was elevated 250%. Corticosterone secretion rate and concentration in plasma were not significantly different in the two groups. These results, in which a tumor provides the primary stimulus for sodium retention, are similar to results reported by others in sodium-deficient rats. A similar mechanism for sodium control is probably operative in both cases.
Gastric secretogogues in postprandial thoracic duct lymph
Authors: Kelly Keith A. , Ikard Robert W. , Nyhus Lloyd M. , Harkins Henry N.
Published: December 2017

Fasting and postprandial thoracic duct lymph was collected from Heidenhain pouch dogs. When autogenous lymph was returned intravenously, postprandial samples stimulated pouch acid output, whereas fasting ones did not. The gastric secretogogues were more active in lymph collected 2–4 hr postprandially than 0–2 hr. After ultracentrifugal separation, both fatty and clear fractions of postprandial lymph contained gastric secretogogues. These stimulatory factors were not present in either clear or fatty fractions of lymph after antrectomy. Histamine was not the gastric secretogogue involved here. The gastric secretogogue present in postprandial lymph may be antral gastrin.
Volume distribution of Evans blue dye and iodinated albumin in the dog
Authors: Huggins R. A. , Smith E. L. , Deavers S.
Published: December 2017

Three hundred seventy-two morphine-pentobarbitalized dogs were divided into groups according to the sampling time after injections of T-1824, I131, or both simultaneously. The data were programmed for digital computer analysis. In dogs receiving the tags separately the mean plasma volume was 50.0 ± 0.63 and 49.8 ± 0.72 ml/kg for dye and I131, respectively. Three simultaneous T-1824 and I131-tagged albumin injections were made with samples taken at 5, 10, 15, 20, 30, 45, and 60 min after each injection. Mixing was complete at approximately 5 min. Mean plasma volumes were 52.5 ± 2.24 ml/kg for the dye and 49.3 ± 1.69 ml/kg for the I131. The difference was not significant. In this group there was a good agreement between plasma volumes when calculated from the seven point curve or from three points only, indicating that all points were part of the same straight line. Therefore, a shorter time period with fewer samples is advantageous. Furthermore, when maximum accuracy is not required, the 5-min sample gives a reasonable estimate of plasma volume.
Influence of microbial flora on xylose absorption in rats and mice
Authors: Heneghan James B.
Published: December 2017

The absence of a microbial flora produced a twofold increase in the absorption of d-xylose in germfree mice as determined by the everted sac technique. The existence of a similar increase was confirmed in germfree rats by using one in vitro and two in vivo techniques. Monocontamination of germfree mice with pure cultures of microorganisms also produced changes in xylose absorption. Studies on water, Na+, and K+ absorption in germfree mice indicated that the flora produces no significant change in the absorption of Na+ or in the movement of water and K+.
Handling of urea and related compounds by the renal tubules of the frog
Authors: Schmidt-Nielsen Bodil , Shrauger Carolyn Ruth
Published: December 2017

A high arginase activity is found in the kidney of the adult frog Rana catesbeiana which actively secretes urea. Urea accumulates in the kidney in concentrations around seven to eight times the blood concentration. To test whether the kidney arginase causes significant formation of urea in tubular cells at normal plasma arginine levels, C14 urea, chemical urea, and creatinine clearances were measured. C14 urea and chemical urea clearances were identical, both being about seven times the GFR. 2,4-Dinitrophenol (DNP) inhibited the active secretion of urea, but C14 and chemical urea clearances remained identical to each other. When arginine was administered, urea was formed in the kidney and excreted in the urine at the rate of 35 µm/g kidney hr. The chemical urea clearance was then about twice the C14 urea clearance. DNP administered with arginine caused the C14 urea clearance to fall below the GFR but did not inhibit the formation of urea as shown by the chemical urea clearance being three times the GFR. Compounds chemically related to urea were handled in different ways by the frog kidney. Acetamide and methylurea were not secreted and did not accumulate in the kidney. DNP had little or no affect on their excretion. Thiourea was found to be actively secreted and to accumulate in the kidney. DNP inhibited thiourea secretion. It is concluded that urea is normally actively transported across the tubular wall and that formation of urea in the tubular cells is insignificant.
Influence of venous injection sites on evolution of dilution curves in dogs
Authors: Lange Ramon L. , Botticelli James T.
Published: December 2017

The role of venous passage of indicator from different venous injection sites on the genesis of right heart and pulmonary artery dilution curves was examined. Right heart and pulmonary artery thermodilution curves were recorded after injection of cool dye into commonly used portals—superior vena caval, right atrial, and inferior vena caval—and the contour compared with the subsequent femoral artery dye dilution curve. With superior vena caval or right atrial injection, the contour and disappearance slopes of the pulmonary artery curve bore an extremely variable relationship to those of the femoral artery curve. In sharp contrast, inferior vena caval injection yielded pulmonary artery curves with disappearance slopes which were highly correlated with the femoral artery slope ( r = .99). With inferior vena caval injection, considerable temporal dispersion and spatial dispersion of indicator is found at the right atrial level. With superior vena caval injection distribution mainly occurred beyond the right atrium and even beyond the pulmonary artery in eight out of ten animal studies. The geometry of the venous system may explain this difference. Inaccuracies in flow calculation from right heart dilution curves in dogs would seem to be minimized by inferior vena caval injection.
Allocation of cardiac output to limb and kidney during hypotensive procedures
Authors: McGiff John C.
Published: December 2017

Cardiac output, and renal and femoral venous outflows were measured simultaneously and continuously by rotameters during hemorrhage and inferior vena caval obstruction. Acute reductions in cardiac output resulted in an immediate increased femoral and renal fraction of the cardiac output, the femoral increasing more than the renal. Further augmentation of the femoral flow fraction with reduction of the renal flow fraction was accomplished by baroreceptor area denervation or guanethidine. Following guanethidine-induced reduction of sympathetic vasoconstrictor activity of the femoral bed, the femoral flow pattern was converted to a renal flow pattern. The partition of cardiac output during acute hypotensive procedures in this experimental setting was determined by differential vasoconstrictor activity, possibly by neurohumoral agents which selectively influence certain vascular beds, and by an intrinsic property of the blood vessel wall which determines in part its response to acute reduction in flow.
Distribution and exchange of calcium in connective tissue and smooth muscle
Authors: Bozler Emil
Published: December 2017

Ca exchange of the frog's stomach muscle was rapid and much larger than in skeletal muscles. More than half of the fiber Ca exchanged and was lost in Ca-free solutions in 10 min. To evaluate extracellular Ca in these experiments exchange and binding of Ca in tendon and fascia were studied. The amount of extracellular Ca was estimated from the loss of Ca in isosmotic sucrose solution. In high Ca solutions the Ca concentration in muscle increased several times, but remained much lower than the Ca concentration in the medium. A large increase in Ca i appears to be associated with a loss of Na and K. The question of how the unequal distribution of Ca is maintained is discussed. Because of the rapid exchange and because of the large difference in concentration of Ca ions the energy requirement of a Ca pump would be prohibitively high. The distribution of Ca can be understood as an equilibrium if Ca enters the fibers bound to a diffusible carrier and if bound Ca competes with monovalent ions for binding sites.
Effect of urea loading on urine osmolality during osmotic diuresis in hydropenic rats
Authors: Koike Thomas I. , Kellogg Ralph H.
Published: December 2017

Osmotic diuresis was induced in hydropenic female rats by intravenous infusion of urea with and without vasopressin. The relationship between urine osmolality and total solute excretion rate was qualitatively similar to that observed during mannitol loading, but the maximal urine osmolalities achieved were markedly higher during urea loading and were unaffected by the simultaneous administration of probenecid or para-aminohippurate. Simultaneous inulin and urea clearances indicated net tubular reabsorption of 23–55% of the urea filtered. The results do not support the view that enhancement of concentrating ability by urea depends upon its active tubular transport.
Relationship of age to pituitary TSH levels and PTU-induced goitrogenesis in the rat
Authors: Levey Harold A.
Published: December 2017

Thyroid weights, adenohypophysial and serum thyroid-stimulating hormone (TSH) levels, and thyroid: serum (T/S) radioiodide concentration ratios were determined in control rats and in PTU-treated littermates of various ages. Adenohypophysial TSH levels were low in the immature control rats and increased progressively with age. Some of the weanlings showed little or no thyroid hypertrophy after treatment with PTU, although others displayed the standard goitrous response. Such variability was not observed in adults. In the goiter-resistant rats, adenohypophysial TSH levels were equivalent to the control values, and serum TSH was below the bio-assay threshold concentration of 0.5 mU/ml, indicating lack of significant release of adenohypophysial TSH. In the goitrous rats, adenohypophysial TSH declined and serum TSH increased, indicating that TSH was discharged from the adenohypophysis. Increases in both T/S ratio and thyroid weight occurred in adult rats treated with PTU for 1 week; but in comparably treated immature rats there was a dissociation of these responses in that the T/S ratio increased without a concomitant elevation in thyroid weight. The low endogenous level of adenohypophysial TSH in the immature rats and failure of TSH release in response to PTU tentatively are considered to result from the absence of physiological maturation of the hypothalamic-pituitary pathway involving control of TSH production and/or release.
Inhibition of intestinal epithelial cell renewal and migration induced by starvation
Authors: Brown H. Oliver , Levine Milton L. , Lipkin Martin
Published: December 2017

Following starvation in mice, the rate of cell renewal of intestinal epithelium was measured. Injection of thymidine-H3 and microautoradiography, and thymidine-C14 and chemical extraction procedure were utilized. Cell renewal was reduced to about one-half the normal rate following extreme starvation. Morphological changes and impaired differentiation of the epithelial cells accompanied this change. The rate of migration of the epithelial cells to the villus tips was also reduced.
Effect of restraint on fasting gastric content of spider monkeys
Authors: Brooks Frank P. , Ridley Peter , Attinger Francoise , Neff Kent
Published: December 2017

The effect of restraint in a chair, compared to conditions permitting free movement, on the fasting gastric content was studied in spider monkeys during 3- and 24-hr experiments. In the 3-hr experiments, the volume and "free" and total acid concentrations were significantly reduced during restraint. The pepsin concentration was increased but not to a statistically significant level. In the 24-hr experiments, there was little change noted in volume and acid concentration throughout the study when the animals were restrained. In contrast the freemoving animals showed a greater volume during the period of daytime activity than when they were restrained, but exhibited a marked decrease in volume and acid concentration during the night. The pepsin concentration during the first 9 hr was significantly greater in the restraint experiments.
Effect of lung-inflating pressure on pulmonary blood pressure and flow
Authors: De Bono E. F. , Caro C. G.
Published: December 2017

In ten dogs the widely exposed left lower lobe of the lung was inflated to different static pressures over the range 5–20 cm H2O while being perfused with blood from a constant-flow source over a range of flows up to 300 ml/min. Left atrial pressure was kept below 3–4 cm H2O. The relationship between perfusion pressure and inflating pressure was linear and the slope independent of perfusion flow rate except at very low rates of flow. The Δ perfusion pressure-to-Δ inflating pressure ratio, with one exception, varied from 0.6 to 1.0, indicating that the major part of alveolar pressure was transmitted to the capillaries. At normal rates of flow the relationship between perfusion pressure and flow was linear. The findings, together with results obtained on a model, suggest that: 1) Calculation of pulmonary vascular resistance from the pulmonary artery-left atrial pressure gradient is misleading where inflating pressure exceeds left atrial pressure. In such circumstances the precapillary resistance can be measured. 2) At normal rates of flow the dominant resistance in the pulmonary vascular bed is precapillary. Despite the distensibility of pulmonary vessels this resistance does not vary with perfusion pressure or flow.
Determinants of stroke work in the dog heart-lung preparation
Authors: Pieper Heinz P. , Ogden Eric
Published: December 2017

The left ventricle in a dog heart-lung preparation was subjected to slowly oscillating changes in arterial pressure load and/or end-diastolic pressure. Classical work curves were obtained when end-diastolic pressure changes were made cyclically and the arterial pressure held constant. When the arterial pressure was oscillated and the end-diastolic pressure held constant, left ventricular stroke work was found to be a function of the arterial pressure. Hence, it is shown that stroke work is a function of both the end-diastolic pressure and the arterial pressure. The performance of the heart was further examined by studying the dependence of the basic quantity stroke output on the two independent variables, arterial pressure and end-diastolic pressure. The relationship between these two independent variables and stroke power was also determined, and it was found that, at low end-diastolic pressure, arterial pressure changes had little effect on stroke power, but that at high end-diastolic pressure, the effect of arterial pressure changes became rather more marked.
DPN- and TPN-C19-steroid dehydrogenases and reductases in accessory sex tissues
Authors: Kinson Gordon A. , Kochakian Charles D.
Published: December 2017

Homogenates of the seminal vesicles and prostate of the rat and guinea pig and the prostate of the dog and man (benign hyperplasia) interconverted testosterone and androstenedione with the use of DPN (DPNH) and TPN (TPNH) as coenzymes. The activity of the enzymes was so small that detection was possible only after the use of the C14-labeled steroids as substrate. The oxidase activity of the prostate of the dog and the prostate and seminal vesicles of the guinea pig was greater with DPN than with TPN. The tissues of the human and rat demonstrated essentially similar activities with either DPN or TPN. The reductase activity of the TPNH system was more effective than the DPNH system for all animal species. Androsterone and small amounts of epiandrosterone also were formed by dog prostate by the DPNH and TPNH systems, respectively.
Cysteine effect on toad bladder response to vasopressin, cyclic AMP, and theophylline
Authors: Handler Joseph S. , Orloff Jack
Published: December 2017

The increase in permeability to water and in short-circuit current of the toad's urinary bladder in response to 1 mU/ml of neurohypophyseal hormone was inhibited by 1 mm cysteine. The response to 10 mm theophylline was inhibited by as little as 0.1 mm cysteine. Cysteine or thioglycollate had no effect on the response to 1–4 mm cyclic-3',5'-AMP. The inhibitory effect of cysteine was evident under circumstances that would not be expected to cause appreciable reduction of hormone or theophylline; namely, low concentrations of cysteine were used, all solutions were well oxygenated, and there was no preincubation of hormone or theophylline with cysteine. The results are interpreted as indicating that cysteine acts at least in part by directly affecting intracellular processes rather than solely by chemical reduction of the hormone or theophylline in the bathing medium.
Effects of atrial and ventricular tachycardias on the cardiovascular dynamics
Authors: Nakano Jiro
Published: December 2017

In anesthetized dogs, the effects of tachycardia on the cardiovascular dynamics were studied. It was observed that atrial and ventricular tachycardias decrease mean arterial pressure, stroke volume, cardiac output, and regional arterial blood flows, and depress ventricular function curves. Moreover, the tachycardias increase myocardial contractile force, pulmonary arterial pressure, left and right atrial pressures, and total pulmonary and regional peripheral resistances. The magnitude of these hemodynamic changes observed in atrial or ventricular tachycardia of the same focus increases in proportion to increases in heart rate. Furthermore, the magnitude of the hemodynamic changes observed in ventricular tachycardia of a given rate is much greater than that observed in atrial tachycardia of an equivalent rate. The mechanisms responsible for the hemodynamic changes observed in tachycardia are discussed.
Influence of kallidin-10 on renal function
Authors: Webster Marion E. , Gilmore Joseph P.
Published: December 2017

The intrarenal infusion of kallidin-10 at 1–3 µg/min in the dog produces an increase in directly measured renal blood flow with no alteration in systemic blood pressure. Concomitant with the increase in blood flow, a diuresis is observed which is associated with substantial increases in sodium and chloride excretion but smaller increases in total solute and potassium excretion. Neither urinary pH nor free water changed consistently. The pattern of water and electrolyte secretion suggests that the observed changes are secondary to an increase in glomerular filtration rate, although an increase in endogenous creatinine or inulin clearance could not be detected. The contralateral kidney showed no changes during infusion of the decapeptide indicating the rapidity with which it is destroyed in vivo. The renal responses to acetylcholine mimic those produced by kallidin-10. These data, together with earlier observations showing that the kidney excretes both the proteinase, urinary kallikrein, and its hypotensive polypeptides, suggest that this enzyme system may contribute to renal blood flow regulation and to salt and water homeostasis.
Effect of anterior and posterior hypothalamic lesions on precocious sexual maturation
Authors: Schiavi Raul C.
Published: December 2017

The comparative effect of anterior and posterior hypothalamic lesions on the development of sexual maturation of prepubertal female rats was investigated. Lesions by electrocoagulation were made in the medial hypothalamus of 45 rats at 25–26 days of age. Thirty-nine animals of the same age constituted the sham-operated and nonoperated controls. A hastened appearance of vaginal opening and first estrus, a significant increase in uterine weight, precocious ovarian luteinization, and premature sexual cycles were observed following both types of lesions. Sham-operated rats and animals with lesions in other parts of the brain did not show evidence of precocious sexual maturation.
Tissue carbon dioxide stores: magnitude of acute change in the dog
Authors: Sullivan S. F. , Patterson R. W. , Papper E. M.
Published: December 2017

Carbon dioxide washout curves were determined in hyperventilated dogs. Direct measurement of mixed venous carbon dioxide tension allowed calculation of changes in whole-body CO2 stores. The average whole-body CO2 dissociation constant in ten studies was 3.73 ml/kg mm. The limiting factor in reaching a new steady-state value was represented by a slow compartment in the washout curve. The average rate constant for this compartment was 0.062 min–1. The slowest compartment in this analysis has a 98% change in 1 hr, therefore the experimentally determined whole-body dissociation constant should closely approximate actual changes in tissue CO2 stores, excluding bone and fat.
Drug action on pulmonary circulation of unanesthetized dogs
Authors: Rudolph Abraham M. , Scarpelli Emile M.
Published: December 2017

A preparation is described which overcomes most of the difficulties previously encountered in the assessment of vasomotor responses of the pulmonary vessels to pharmacologic agents. The use of electromagnetic flow transducers on the main and left pulmonary arteries allows for the observation of immediate local effects following unilateral drug administration before general systemic effects occur. The opposite lung serves as a control, since it is subjected to the same changes of left artrial pressure, pulmonary arterial pressure, and pulmonary blood flow as the test lung. Our studies have demonstrated a direct pulmonary vasoconstrictor response to 5-hydroxytryptamine and acetylcholine in both the conscious and anesthetized dog. Epinephrine was also shown to have a direct pulmonary vasoconstrictor activity, but this could be elicited in only three of the eight dogs studied. Isoproterenol, methoxamine, aminophylline, phenylephrine, γ-amino butyric acid and pentobarbital had no apparent direct pulmonary vasomotor effect.
Marrow transplantation measured by uptake of Fe59 by spleen
Authors: Smith L. H.
Published: December 2017

Transplantation of isologous (syngeneic) bone marrow into lethally X-irradiated mice has been quantified in terms of the degree to which the spleen incorporates Fe59. Spleen uptake of Fe59 is linear with bone marrow cell dose and reflects the erythropoietic integrity of the transplanted cells. Parameters of the assay were investigated including X-ray exposure to the recipient, time of assay, Fe59 uptake time and plasma clearance of the isotope. The following protocol was adopted: (C3H x C57BL) F1 male mice are a) exposed to 850 r of X rays, b) injected with bone marrow 24 hr later, c) given Fe59 8 days later, and d) killed 6 hr after isotope injection to obtain spleens for Fe59 analysis. The assay was used to determine radiosensitivity of the erythropoietic compartment of marrow and to determine integrity of marrow cells after short-term culture as a means of studying in vitro recovery from radiation damage. Results showed that the in vitro radiation exposure required to reduce the surviving cells to 37% (D37) was 75 r. Studies of normal cells in short-term culture showed that cell integrity could be maintained for at least 6 hr in Tyrode's solution with calf serum at 22 C but that integrity was reduced after 6 hr at 37 C in all media tested.
Mechanism of platelet plug formation and role of adenosine diphosphate
Authors: Spaet Theodore H. , Zucker Marjorie B.
Published: December 2017

Traumatized rat omentum was used to demonstrate the development of "platelet plugs" following agitation in platelet-rich plasma. In the absence of divalent cation there was only platelet adhesion to connective tissue fibers; in the presence of divalent cation masses of platelets formed (cohesion) even in plasma adequately anticoagulated with heparin. Exposure of these platelet masses to thrombin produced greater compactness and stability. Human and rat platelets behaved alike with the traumatized rat omentum; platelets from two patients with von Willebrand's disease gave normal reactions whereas platelets from a patient with thrombasthenia showed adhesion only. Exposure of human platelets to washed connective-tissue fragments or to thrombin elicited clumping accompanied by release of serotonin and of adenine nucleotides (AN) of which about one-third was adenosine diphosphate. Intermediate concentrations of connective tissue and thrombin also caused clumping but no liberation of AN or serotonin. ADP caused intense clumping but failed to liberate serotonin or additional ADP. It is suggested that cohesion reaction is mediated by release of ADP. The traumatized omentum appears to be a suitable model for studying the hemostatic process.
Total body water in farm animals
Authors: Hansard Sam L.
Published: December 2017

Dilution procedures with tritium and labeled and unlabeled pyrazolones were used to measure total body water in 89 swine, 99 cattle, and 170 sheep, grouped for convenience of presentation into two age-weight groups. Mean plasma disappearance rates for injected antipyrine were 45, 23, and 28%/hr, and loss of antipyrine reversibly bound to plasma protein was 35, 22, and 32% for swine, cattle, and sheep, respectively. Greatest loss of the test substances was via the urine. Total body-water values were significantly higher ( P < 0.05) in ruminant animals than in swine, and observed age differences were greater ( P < 0.01) than differences between methods. Results favored tritium as the indicator of choice because of its rapid equilibration with body water, slow plasma protein binding, and decreased metabolic breakdown. Concurrent use of two or more indicators having different volume distributions offer advantages for use in ruminant animals over monogastric animals for the correction of body composition data for gastrointestinal water.
Arterial hematocrit and separation of cells and plasma in the dog kidney
Authors: Chinard Francis P. , Enns Theodore , Nolan Mary F.
Published: December 2017

With the indicator-dilution technique, the mean transit times of cells (tr) labeled with Cr51 and of plasma (tpl) labeled with T-1824 or as human albumin-I131 decrease as the arterial hematocrit (Hct) decreases. The regression equations are: tr = 0.0388 Hct + 1.73 and tpl = 0.0596 Hct + 1.69. The separation of cells and plasma labels, as measured by the difference of the mean transit times (Δt), is also related to the hematocrit. Δt = 0.00895 Hct + 0.269. There is an excess plasma label volume of distribution per 100 g kidney, ΔVpl, which may be intra- or extravascular. ΔVpl = QrΔt (1 - Hct), where Qr is blood flow per 100 g kidney. ΔVpl is independent of tr and of Hct. However, ΔVpl increases with Qr. ΔVpl = 0.127 Qr + 1.79. The hypothesis that the separation of cells and plasma results from transcapillary passage of the plasma labels is consistent with but is not established by the data.
Genesis of Korotkoff sounds
Authors: Chungcharoen D.
Published: December 2017

Korotkoff sounds were produced in anesthetized dogs and studied in detail. The change in the pattern of blood flow was demonstrated by cinefluorographic technique. Various mechanisms producing Korotkoff sounds are discussed. It was demonstrated that heart sounds and Korotkoff sounds are distinct and separate entities since they are separable in time and are differently influenced by changing the site of the sensing element. These experiments demonstrate that turbulence occurred in flow (corresponding with Korotkoff sounds) despite the fact that the calculated Reynolds numbers were low. The vessel wall is not necessary to the production of Korotkoff sounds.
Effects of ouabain on tissue calcium and calcium exchange in pacemaker of turtle heart
Authors: Govier William C. , Holland William C.
Published: December 2017

The effects of ouabain in positive inotropic (10–7 m) and toxic (10–6 m) concentrations on the tissue calcium content and exchange in the sinus venosus or pacemaker, atrium, and ventricle of the spontaneously beating, in situ, perfused turtle heart were compared. Tissue calcium was measured with a flame photometer, and calcium exchange was determined by the use of Ca45. Solutions were prepared in a cold-blooded animal Ringer's solution. Heart rate remained constant during perfusion with 10–7 m ouabain, but the 10–6 m concentration produced varying arrhythmias. The toxic concentration produced an increase in tissue calcium in all chambers. 10–7 m Ouabain produced an increased calcium exchange in all chambers and a drop in tissue calcium in the pacemaker. The calcium content of the atrium and ventricle remained unchanged at this concentration. The decrease in pacemaker calcium is interpreted as a release of calcium by ouabain allowing the calcium to pass down a concentration gradient into the medium.
Uptake of cholesterol by segments of small intestine of rat
Authors: Shamma'a Munir H. , al-Khalidi Usama
Published: December 2017

A modification of Agar's technique for tissue accumulation was adapted to the study of cholesterol uptake. This technique demonstrated a significant uptake of radioactive cholesterol by segments of the small intestine. The reduction of this uptake to about one-third its initial value by 2,4-dinitrophenol and potassium cyanide suggests that in addition to simple diffusion an energy-requiring mechanism is possibly involved in cholesterol uptake by the small intestine. In the colon such a mechanism was not demonstrated. The degree of uptake at different levels of small intestine, as well as the effect of temperature and concentration of cholesterol are reported.
Tissue glycogen fractions of the hypothermic rat, hamster, and turtle
Authors: Platner W. S. , Shields J. L. , Purdy F. A.
Published: December 2017

Hypothermia in fasted rats caused reduction of both glycogen fractions in liver and heart but did not affect skeletal muscle. Forced respiration during hypothermia prevented the reduction of residual glycogen in heart, but did not otherwise alter the tissue glycogen response to hypothermia. Bilateral adrenalectomy did not prevent the loss in hypothermia of either glycogen fraction from heart or liver. Prevention of shivering by curare during hypothermia failed to maintain control levels of liver or heart glycogen fractions. Incorporation of intraperitoneal glucose-C14 into tissue glycogen of hypothermic rats was increased in soluble and residual fractions of heart, but not in liver or muscle. It was concluded that disappearance of hepatic glycogen in hypothermia may be due to an accelerated glucose utilization by myocardium, and furthermore, that soluble glycogen is the more labile fraction. The same tissues of hamsters and turtles showed no changes in either glycogen fraction due to hypothermia.