bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in inorganic phosphate excretion induced by renal arterial infusion of calcium
Authors: Lavender A. R. , Pullman Theodore N.
Published: December 2017

Calcium chloride in varying concentrations was infused at a slow and constant rate into the renal artery of one kidney in the dog. The opposite kidney served as a control. In 20 experiments, the mean glomerular filtration rate and effective renal plasma flow diminished in the infused relative to the noninfused kidneys. Mean phosphate excretion was decreased in the infused relative to the control kidneys by both a fall in filtered phosphate and a rise in the net tubular reabsorption of phosphate. Mean calcium, sodium, and water excretion did not change in the infused relative to the control kidneys during calcium infusion. The data indicate that hypercalcemia acts directly on the kidney to decrease phosphate excretion by decreasing glomerular filtration rate and increasing net tubular reabsorption of phosphate.
Compensatory adaptation of renal functions in the unanesthetized rat
Authors: Peters G.
Published: December 2017

In normal male rats infused intravenously with 0.1–0.9 ml/kg min 0.15 m NaCl, urine flow increased with the rate of infusion, and CIn increased as a linear function of urine flow. After functional exclusion of one kidney, "compensatory hyperfunction," defined as a permanent increase in glomerular filtration rate ( GFR), began during the 2nd week. Changes in the functions of the remaining kidney occurring earlier than any increase in GFR are termed "compensatory adaptation." The main change noted in compensatory adaptation was a decrease in tubular sodium reabsorption followed by a nearly doubled rate of urine flow and large increases in sodium and potassium excretion. The fall in hematocrit value was the same as in controls. Compensatory adaptation began during the 1st hr, and was complete 2 hr after removing one kidney or ligating one ureter. Changes in renal functions after both types of operation were indistinguishable. Maximum urinary concentration in dehydrated rats treated with vasopressin was not depressed during compensatory adaptation, although urine flow per kidney was doubled.
Relation of fatty acid structure to release and esterification of free fatty acids
Authors: Hollenberg C. H. , Angel A.
Published: December 2017

After incubation of rat adipose tissue with corticotrophin in buffer-albumin, the composition of the free fatty acids (FFA) in the tissue and in the medium was determined; the medium contained proportionately more myristic, palmitoleic, linoleic, and linolenic acids. The ratio of the amount of each free acid in the medium to that in the tissue increased with decreasing chain length and increasing unsaturation. Free acids produced in adipose tissue by corticotrophin stimulation were esterified by subsequent exposure of the tissue to glucose and insulin. Among the saturated and monoenoic acids the shorter chain components were esterified to a greater extent, while at a given chain length the more unsaturated acids were more readily esterified. Thus the more polar FFA were more readily released from and esterified in adipose tissue. These results could have been produced by a variety of processes including differences between the acids in aqueous solubility or the presence of tissue-binding sites with varying affinities for the different acids.
Acid lipase and phospholipase activity in homogenates of rabbit polymorphonuclear leukocytes
Authors: Elsbach Peter , Rizack Martin A.
Published: December 2017

In homogenates of rabbit polymorphonuclear leukocytes from peritoneal exudates, three different lipid splitting activities have been found by measuring the release of fatty acids using the following lipid substrates: 1) a commercial coconut oil suspension indicating lipase activity, 2) synthetic dipalmitoyllecithin or purified brain phospholipid demonstrating phospholipase activity, and 3) lysolecithin prepared from egg lecithin indicating lysophospholipase activity. Both lipase and phospholipase activity manifested a sharp pH optimum at pH 6.0. The lysophospholipase activity exhibited a distinctly alkaline pH optimum. Most activity was found in the 8,200 x g supernatant fraction of the homogenate, but considerable lipase and phospholipase activity was also associated with the granules of the leukocytes. However, little lysophospholipase activity was present in the granule fraction. Freezing and thawing increased lipase activity of the whole homogenate and the granules, but destroyed phospholipase activity. Since phagocytosis is accompanied by a fall in intracellular pH, the possibility exists that the lipid splitting activities with acid pH optima play a role in the events that occur during phagocytosis.
Central cardiovascular responses to submersion asphyxia in the duck
Authors: Johansen Kjell , Aakhus Trygve
Published: December 2017

Pressure recordings from the central systemic veins, the aorta, the left ventricle, as well as intratracheal pressure, have been obtained during simulated dives of domestic ducks. Upon submersion a conspicuous bradycardia gradually developed. The systemic arterial pressure did not change significantly during the profound bradycardia. There was a distinct increase in the central venous pressure and in the diastolic pressure of the left ventricle. The pressure increase surpassed a concomitant intratracheal pressure rise. The circulation time from the right atrium to the base of the aorta was prolonged four to five times during profound bradycardia. The data suggest that the stroke volume remains unchanged or decreases in spite of an increased filling pressure. The increased transit time through the lungs is suggestive of an increased resistance to flow in the pulmonary bed. The data also indicate an increased resistance to outflow from the larger systemic arteries. It is suggested that a marked change in the activity of the autonomic innervation to the myocardium takes place during submersion.
Effect of thyroxin on assay of thyroid-stimulating hormone
Authors: Saatman R. R. , Tienhoven A. Van
Published: December 2017

The per cent colloid in the thyroid of the 3-day-old cockerel provides a sensitive measure of exogenous thyroid-stimulating hormone (TSH) potency. The smallest detectable dose of TSH is 0.5 mU; the log dose-response relation is linear between 5–500 mU of TSH, with a slope of –19.09 ± 0.90% colloid per unit log dose (mU) TSH, and an index of precision (λ) of 0.21. The assay method shows good repeatability. Statistically, no interaction was detected in a 5 x 5 factorial experiment in which TSH was administered (5 times at 12-hr intervals in doses of 0, 3, 9, 27, or 81 mU) with dl-thyroxin (in doses of 0, 0.04, 0.16, 0.64, or 2.56 µg/injection). No TSH could be detected in the pituitaries of starved or fed 3-day-old cockerels when the equivalent of a total of five pituitaries per assay chick was administered.
Reaction of isolated pig iris sphincter to electrical stimulation and acetylcholine
Authors: Schaeppi U. , Koella W. P.
Published: December 2017

The isolated iris ring of the pig irrigated with Tyrode's solution was suspended on two platinum hooks which served as stimulating electrodes. Isometric contractions of the iris sphincter were elicited by injections of acetylcholine (ACh) into the bathing medium or by short periods of electrical stimulation. The results obtained with atropine, Prostigmine, diisopropylfluorophosphate and Xylocaine suggested that electrical stimulation produced sphincter contractions indirectly, i.e., via activation of postganglionic nerve fibers and release of ACh. The effects of electric stimulation or of administration of ACh differed in many respects from those induced by stretch. A dose of atropine or iodoacetate which prevented the effect of the former two procedures did not attenuate the latter. Stretch enhanced the reactivity to injections of ACh and electrical stimulation; continuous administration of ACh initially increased and then decreased the contractile responses to strong electrical stimuli or single superimposed injections of ACh. Prolonged electrical stimulation usually decreased the effect of superimposed administration of ACh.
Oxygen deficit and irreversible hemorrhagic shock
Authors: Crowell Jack W. , Smith Elvin E.
Published: December 2017

A device was constructed to record continually the oxygen consumption of a dog and to summate as the oxygen deficit the difference between normal oxygen use and oxygen use during hypotension. Dogs were subjected to hypotension of 30 mm Hg and various oxygen deficits were allowed to accumulate. It was found that oxygen deficits of 100 mg/kg or less were not lethal. Oxygen deficits of 120 ml/kg produced an ld50, and oxygen deficits of 140 ml/kg or greater were invariably fatal. Digitalization was beneficial to the dogs. Dibenzylene and conditioning of the animals to periods of hypotension proved to be of no value when the animals were subjected to a definite oxygen deficit equal to that in control animals. Neither epinephrine nor norepinephrine changed the mortality rate for a given oxygen deficit.
Parathyroid hormone and release of calcium 45 from bone
Authors: Jeffay Henry , Bayne Harold R.
Published: December 2017

An attempt was made to determine from which compartment of bone the calcium is released under the influence of parathyroid hormone. To do this, rats were raised on a homogeneous diet containing calcium 45. When the calcium of the bones and blood had the same specific activity as the diet, the rats were maintained on a normal nonradioactive diet until the specific activity of the different compartments were grossly different. Parathyroid hormone was then administered intraperitoneally, and the changes in specific activity of bones and serum were measured. The results show the increase in serum calcium following hormone treatment does not come entirely from the rapidly exchangeable compartment, but rather that parathyroid hormone also affects the slower exchanging fraction bone.
Implications of urine pO2 for renal medullary blood flow
Authors: Aperia Anita C. , Liebow Averill A.
Published: December 2017

The pO2 of ureteral urine under osmotic diuresis responds inversely to changes in renal arterial and venous pO2. With a rise in arterial pO2 there is only a transient increase but then a rapid fall in urinary pO2, usually to lower than the initial levels in both anesthetized and unanesthetized dogs. Opposite changes occur when the arterial pO2 is diminished. The renal blood flow falls as arterial pO2 rises with transfer of the animal from air to 100% O2, but the total O2 consumption of the kidney remains unaltered. The most simple and reasonable explanation of these findings postulates the existence of a mechanism sensitive to arterial pO2 for redistribution of medullary blood flow. This does not, however, rule out the possibility that an increase in arterial pO2 might be accompanied by an augmentation of O2 utilization so large as to diminish tissue pO2, and vice versa. If this is true there is, to our knowledge, no analogue in biology and there are several points of evidence against the metabolic hypothesis.
α-Glycerophosphate metabolism in muscle under aerobic and hypoxic conditions
Authors: Peterson Ruth D. , Gaudin David , Bocek Rose Mary , Beatty Clarissa H.
Published: December 2017

A significant amount of α-glycerophosphate (α-GP) was present in voluntary skeletal muscle of rats when the hind limb was frozen in situ. Ischemia of this muscle in situ caused a 7-fold increase in α-GP concentration and a 12-fold increase in lactate concentration. In vitro experiments with diaphragm muscle from rats and adductor fiber groups from rats and monkeys also demonstrated that hypoxic conditions caused a 2.5- to 4-fold rise in α-GP levels. The α-GP concentration in hypoxic red muscle was higher than that in hypoxic white muscle from rats. Lactate diffused into the medium from all types of muscle preparations. However, under aerobic conditions no measurable amount of α-GP appeared in the medium surrounding the fibers and only a small amount diffused out of the diaphragm muscle. Even when incubation was carried out under hypoxic conditions little α-GP was present in fiber medium. Although the diaphragm released ten times as much α-GP as the fiber groups, this amount was small in relation to lactate production. These data indicate that under anaerobic and hypoxic conditions dihydroxyacetone phosphate can compete with pyruvate for the cytoplasmic NADH in diaphragm and voluntary skeletal muscle.
Micropuncture study of hypertonic sodium chloride loading in the rat
Authors: Giebisch Gerhard , Klose Ruth M. , Windhager Erich E.
Published: December 2017

The proximal and distal tubular sodium transport systems were studied under conditions of an increased sodium load. Fluid was collected by micropuncture from various sites along the nephron of rats receiving a 4% sodium chloride infusion. Samples were analyzed for sodium and inulin-C14, and compared with those obtained from a nondiuretic control group. Inulin clearances were higher in the sodium chloride-loaded rats while their over-all fractional sodium reabsorption was significantly reduced. In animals in which the urinary excretion rate of sodium remained below 12% of the filtered load, fractional sodium and water reabsorption within the proximal tubule were not different from the control group. Under these conditions, no proximal maximal tubular transfer rate for sodium could be observed. Only when urinary excretion rates of sodium exceeded 12% of the filtered load was fractional proximal tubular sodium reabsorption depressed. During sodium chloride loading fractional sodium reabsorption was always reduced in the distal tubule and the collecting duct when compared with the control group. Since this distal tubular transfer capacity does not substantially increase, the natriuretic and diuretic response to an elevation of the plasma sodium concentration is effected by surpassing a distal tubular transport maximum for sodium.
Characteristics of potassium conservation by the dog kidney
Authors: Lemieux Guy , Warren Yves , Gervais Marc
Published: December 2017

During simultaneous restriction of sodium and potassium to 1 and 2 mEq/day, respectively, it has been demonstrated that the dog kidney has a remarkable capacity to conserve potassium, the urinary excretion of this ion decreasing rapidly to equal the intake within 4–5 days. Subsequent administration of sodium 100 mEq/day in the form of chloride failed to influence renal conservation of potassium. Equivalent administration of sodium in the form of sulfate or neutral phosphate resulted in a transient but unequivocal increase in urinary excretion of potassium. When desoxycorticosterone 1 mg/kg day was given while high sodium intake and potassium restriction was continued, significant increase in urinary excretion of potassium was observed regardless of the anionic form in which sodium was given. It is suggested that chloride, a readily permeant anion, may prevent significant tubular sodium-potassium exchange. This effect would appear to be overcome when large amount of mineralocorticoid is acting on the renal tubules.
Differences in specific activity of calcium in blood and urine of dogs
Authors: Miller E. J. , Neuman W. F. , Bazerque P. M.
Published: December 2017

Following intravenous administration of radioactive calcium, no differences were observed between blood and urine calcium specific activities even at early time periods. Following intraperitoneal administration of similar isotope solutions, however, a considerable discrepancy was noted between the specific activity in the two compartments, the urine specific activity remaining lower than that of the blood for as long as 5 hr. This same phenomenon was apparent after intravenous administration of radioactive calcium if a solution were injected intraperitoneally at the time of isotope administration. Blood/urine specific activity ratios exceeding unity were associated with periods of low calcium excretion. Adrenergic drugs, injected intravenously, were found to mimic intraperitoneal injections of isotope solutions. The response to intraperitoneal injections could not be blocked by atropine, but was absent in the presence of Dibenamine. It was concluded that an intraperitoneal injection had altered renal hemodynamics through a neural response which appeared to be sympathetically mediated. No evidence was found for a nonhomogeneous distribution of exogenous labeled calcium among the plasma calcium fractions. It is suggested that kidney tissue calcium is the source of the disproportionate amount of stable calcium appearing in the urine.
Hyperlipemia and ketosis in the pregnant rat
Authors: Scow Robert O. , Chernick Sidney S. , Brinley Marlene S.
Published: December 2017

Pregnant rats fasted on the 18th or 19th day of gestation developed hypoglycemia, severe ketosis, and hyperlipemia. The latter, which consisted primarily of triglycerides, was accompanied by increased plasma free fatty acids and accumulation of fat in the liver and kidneys. The effects of fasting were diminished by starting the fast earlier in pregnancy or by hysterectomy. Both ketosis and hyperlipemia were corrected by administration of insulin, tolbutamide, or glucose. The findings indicate that increased fat mobilization and ketosis in fasting pregnant rats are the result of insulin lack. It is suggested that the high priority of the fetuses for glucose reduced the maternal blood glucose concentration to a level too low to stimulate insulin secretion during fasting. Fasting did not alter the rapid growth of the fetuses. Pregnant rats fed ad libitum also developed hypertriglyceridemia if the diet contained fat. This hyperlipemia, unlike that in the fasted rats, was not due to increased fat mobilization and was unaffected by insulin administration. It is concluded that the fractional clearance of blood triglycerides is greatly reduced during late pregnancy.
Function of each lung of dogs during intermittent positive-pressure breathing
Authors: Rehder Kai , Theye Richard A. , Fowler Ward S.
Published: December 2017

The distribution of tidal air and nonshunted blood flow to each lung, the elimination of CO2 from each lung, and Paco2 were measured in ten anesthetized and paralyzed dogs during intermittent positive-pressure breathing in the supine position and before and after thoracotomy in the lateral decubitus position. Ventilation via a divided tracheal airway (Wright-Lategola) at a constant rate and a constant volume (±5%) with 65% oxygen in nitrogen was provided by a Bird ventilator. Reduction of total CO2 elimination and increase of ratio of total physiologic dead space to tidal volume were observed after thoracotomy. Mean percentages of total ventilation and blood flow to, and CO2 elimination from, the right lung were about 58% in the supine position. When the right or left lung became dependent in the lateral decubitus position, its proportional ventilation and CO2 elimination decreased. After thoracotomy was made on the superior nondependent side, further reductions were noted and blood flow to the dependent lung also decreased. Proportional CO2 elimination was more dependent on alveolar ventilation than on the ratio of ventilation to perfusion.
Separation of pepsinogen II and pepsinogen III from human urine
Authors: Seijffers Max J. , Segal Harry L. , Miller Leon L.
Published: December 2017

Human urine has been fractionated on diethylaminoethyl cellulose to yield two pepsinogens. They have been called pepsinogen II and pepsinogen III on the basis of chromatographic behavior identical to that of fundic mucosal pepsinogens II and III. Pepsinogen I has been found absent from 23 urine specimens of 12 individuals. Results suggest a gross qualitative and quantitative correlation between pepsinogen II-pepsinogen III ratio (in terms of total proteolytic activity) in urine and gastric mucosa.
Neural limitations of visual excitability. VII. Nonhomonymous retrochiasmal interaction
Authors: Battersby W. S. , Oesterreich R. E. , Sturr J. F.
Published: December 2017

Visual excitability changes were obtained from two trained observers by measuring threshold with a brief test flash of light at varying temporal intervals from the onset of a longer, supraliminal conditioning flash. The test target was either a 1°20' or a 5°20' solid disc, and was exposed to the right eye at 6°40' along the horizontal meridian in the temporal half field. The conditioning target was a 6°40' disc containing central masks of various angular subtenses, and was so placed in the left eye that the resulting annuli surrounded the test target in the binocularly fused field of view. For all conditions, threshold rose when test preceded conditioning flash in time, reaching a maximum at about o-msec interval between onsets. As the test flash was progressively delayed in time, thresholds fell to an asymptote, returning to resting level after termination of the conditioning flash. The smaller the mask diameter in the center of the conditioning target, i.e., the tighter the fit around the binocularly fused test target, the greater the maximum rise in threshold in the other eye. With small test targets, greater threshold changes were produced by conditioning targets with small masks than by those without a mask (solid targets). Observations on a third observer indicate that similar findings obtain when conditioning stimuli are equated for total luminous flux. These data indicate that retrochiasmal interaction is greater at target borders, and are compatible with recent unit studies on the cortical receptor field.
Trigger mechanism of endotoxin shock
Authors: Vick James A.
Published: December 2017

Studies were carried out utilizing an isolated saphenous vein in an effort to define the substances active in the "trigger" mechanism of endotoxin shock. Data presented indicate that plasma, platelets, and endotoxin are involved in this mechanism. The plasma factor is dializable, heat labile, and has a molecular weight of from 10,000 to 20,000. The product of this combination resembles histamine in that it is blocked by antihistaminics and its effect on vessel contraction is similar, with the exception of an initial lag period. The fact that platelets are a rich source of histamine adds weight to the thesis that histamine may be the factor involved in the trigger mechanism of endotoxin shock.
Role of oxygen in autoregulation of blood flow in isolated vessels
Authors: Carrier Oliver , Walker James R. , Guyton Arthur C.
Published: December 2017

The role of oxygen in control of local blood flow was investigated in isolated arterial segments 1 cm in length and 0.5–1.0 mm in diameter by perfusion with blood of various Po2 levels. A decrease in vascular resistance always occurred when the Po2 was lowered and an increase occurred when it was raised. In 20 vessels, using constant-pressure perfusion, an average increase in conductance of 2.38 times normal level was obtained when the Po2 was lowered from 100 to 30 mm Hg. When this datum was plotted according to initial flow, the smaller vessels gave the greatest response to low oxygen (2.73 times normal; sem ± 0.15), whereas the largest gave the least (1.76 times normal; sem ± 0.10). Forty-three vessels perfused under constant-flow conditions gave results which were consistent with and confirmed the constant-pressure results. In all of these experiments pH, Pco2, and temperature were monitored and kept at physiological levels. The results indicate that oxygen could well be a factor in the autoregulation of blood flow.
Acidosis and blood epinephrine levels in hemorrhagic hypotension
Authors: Darby Thomas D. , Watts Daniel T.
Published: December 2017

Dogs were anesthetized with pentobarbital 30 mg/kg. Cannulas were placed for measurement of arterial and central venous blood pressures. The left femoral artery was cannulated and attachment was made to a reservoir set to maintain arterial blood pressure at 40 mm Hg. Blood pH, pCO2, and pO2 were obtained concomitantly with measurements of blood epinephrine levels utilizing the rat uterus assay method. Rapid hemorrhage to 40 mm Hg blood pressure elicited increments in blood epinephrine levels that closely followed the development of uncompensated acidosis. Correction of the acidosis by intravenous administration of tromethamine or sodium bicarbonate at a blood pressure of 40 mm Hg reduced the blood epinephrine levels by at least 50%, markedly improved cardiac function, increased hemorrhage volume, reduced respiratory rate, and, paradoxically, increased arterial pO2. In vitro studies showed that acidosis did not inhibit destruction of epinephrine added to blood. It was concluded that the adrenal gland is stimulated by acidosis to secrete epinephrine. This stimulation is an important source of blood epinephrine during periods of hypotension associated with shock.
Immediate responses of collateral vessels to abrupt arterial occlusion
Authors: Roy Albert J. , Lambert Peter B. , Frank Howard A.
Published: December 2017

The vascular bed of the hamster cheek pouch was observed in vivo under the microscope as a major artery within the field was occluded. Two changes were noted: 1) an alteration in pattern of blood flow and 2) the opening of previously unseen branches on each side of the ligature. Both responses were immediate and persisting. Besides providing for new flow patterns, the newly opened arterial branches preserve additional length of the ligated artery which becomes obliterated on each side of the ligature to the nearest open branch. Comparison of in vivo with postmortem observations indicated that latent and open branches of the artery under observation were about equal in number, and that about half of the latent branches opened in response to the ligation. Induced vasoconstriction delayed the opening of latent branches, cold prevented it. Priscoline opened all latent vessels, with or without arterial ligation. In connection with Burton's data on "critical closing pressure" of fine vessels, the ligation of a large artery appears to establish a "critical opening pressure" within latent branches.
Effects of cyanide, Q0, and dinitrophenol on renal sodium reabsorption and oxygen consumption
Authors: Fujimoto M. , Nash F. D. , Kessler R. H.
Published: December 2017

Effects on sodium reabsorption and oxygen consumption of the renal arterial injection of three metabolic inhibitors were studied by unilateral clearance techniques in anesthetized dogs. In control studies, 21.5 ± 2.3 mEq sodium were reabsorbed per millimole oxygen consumed within a range of sodium reabsorption of from 2 to 9 mEq/min. A total dose of 10–4 m cyanide depressed both sodium reabsorption and oxygen consumption in the injected kidney. Administration of 10–4 m Q0, the quinone nucleus of coenzyme Q, reduced sodium reabsorption and had a variable effect on O2 consumption. Dinitrophenol, in a total dose of 10–3 m, increased oxygen consumption without affecting the per cent of filtered sodium that was reabsorbed. The resultant Na:O2 ratios were 12:1. We conclude that the major fraction of O2 consumption energizes sodium reabsorption in the kidney perhaps via the classic route of ATP synthesis and hydrolysis. However, all three compounds used in this study would be predicted to decrease renal ATP concentrations. Yet only cyanide and Q0 decreased sodium reabsorption. Energy for sodium movement may come directly from oxidative metabolism bypassing synthesis and breakdown of ATP.
Na transport by isolated turtle bladder during anaerobiosis and exposure to KCN
Authors: Klahr Saulo , Bricker Neal S.
Published: December 2017

The isolated urinary bladder of the fresh-water turtle is lined with a single layer of epithelium, and in common with other polar epithelial cell tissues, actively transports sodium from mucosa to serosa in oxygenated Ringer's solutions. This transport is associated with a spontaneous potential gradient (serosa positive to mucosa). Of unusual biologic interest is the fact that Na transport is maintained under anaerobic conditions; and in contrast to frog skin and toad bladder, net rates of anaerobic transport averaged over 90% of aerobic values. Under aerobic conditions, the short-circuit current exceeded net sodium transport by approximately 15%. However, in deoxygenated Ringer's, net transport appreciably exceeded short-circuit current. With 10–3 m KCN, net transport not only persisted, but increased, and in common with the response in deoxygenated Ringer's, net Na flux to short-circuit current ratios increased. The isolated turtle bladder presumably is capable of providing energy for electrolyte transport via anaerobic metabolism. Because anaerobic glycolysis is less complex than oxidative metabolic pathways this structure could provide a valuable model for investigating energetics of active transport.
Behavioral thermoregulation in response to local cooling of the rat brain
Authors: Satinoff Evelyn
Published: December 2017

Local cooling of the anterior hypothalamic-preoptic area in rats, at environmental temperatures of 5 and 24 C, caused their rectal temperatures to increase as much as 3.1 C, as well as vigorous shivering. When the animals were allowed to press a bar to turn on a heat lamp directly overhead, they pressed more at both ambient temperatures when their brains were cooled than when they were not, although they worked harder in the cold. They shivered continuously during brain cooling at either temperature. The behavioral and physiological temperature regulations appeared to be complementary, since the same temperature levels were reached whether or not heat could be obtained voluntarily. Central cooling produced, in addition to the usual reflex mechanisms of increased body temperature and shivering, the behavioral motivation for heat.
Unit activity during polarization of the optic tract and lateral geniculate body
Authors: Vastola E. F. , Rosen A. D.
Published: December 2017

Records of activity in single cells of the optic tract and lateral geniculate body during prolonged anodal and cathodal polarization with a large extracellular electrode indicate that both kinds of polarization applied to fiber tracts or in the nuclear region can interrupt the transmission of action spikes at strengths as low as 0.15 ma; cathodal polarization was more effective than anodal polarization. Both kinds of polarization were also found to elicit repetitive propagated activity which varied in frequency with the strength of polarizing current; anodal polarization was much more effective in this regard. Repetitive activity was generated when the polarizing electrode was placed among fibers many millimeters from their cell bodies and axonal endings and when the polarizing electrode was placed in a nuclear region. Repetitive activity during anodal polarization is believed to originate in regions of induced depolarization accompanying the outward flow of polarizing current across the membrane at some distance from the polarizing electrode.
Effect of aldosterone and cortisol on sodium and water content of the rat kidney
Authors: Kessler Edward , Allen Royal L. , Kirman David , Strauss Herbert
Published: December 2017

The present studies were undertaken to determine the effect of aldosterone and cortisol on the sodium content of the kidney. Rats were injected intraperitoneally with 50 µg of d-aldosterone or 100 µg of d, l-aldosterone, or with 2 mg of cortisol. Three to four hours later the kidneys were removed and analyses of sodium and water in the papilla, medulla, and cortex were performed. Aldosterone in both normal and adrenalectomized animals and cortisol in adrenalectomized animals increased the sodium concentration in the wet tissue, tissue water, and tissue solids in all areas of the kidney. Papillary sodium and cortical water were reduced in the adrenalectomized animals. Cortisol, in addition to its effects on sodium, restored cortical water to levels observed in normal control animals, while aldosterone had no influence on water in any area of the kidney. The magnitude of increase of sodium in the tissue solids of the cortex was greater with aldosterone than with cortisol.
Effect of hydrogen ion changes on vascular resistance in isolated artery segments
Authors: Carrier Oliver , Cowsert Meredith , Hancock John , Guyton Arthur C.
Published: December 2017

Isolated arterial segments, 1 cm in length and 0.5–1.0 mm in diameter, were perfused with Tyrode's solution titrated to various levels of pH. Po2, Pco2, and temperature were held at physiological levels; the perfusion pressure was held at 100 mm Hg, and flow was measured by a drop counter. There was a linear increase in flow as the pH was decreased from 7.4, 0.05 units at a time, with an increase of 87% obtained at pH 7.15. As the pH was further decreased, the flow dropped until at pH 6.8 it leveled off slightly above control level. When the pH was raised, there was an initial 35% decrease in flow by the time pH 7.50 was reached, followed by an increase, reaching 50% above control level at 7.65. At still higher pHs a precipitous decrease in conductance occurred, flow leveling off slightly below control level at pH 7.80. Consistent results were obtained on 45 vessels using Tyrode's solution titrated to the desired pH with lactic acid, hydrochloric acid, acetic acid, sulfuric acid, nitric acid, sodium hydroxides, or sodium bicarbonate. These results indicate that vessels have a very narrow pH range in which they maintain physiological tone.
Changes in shunt flow, compliance, and volume of lungs during apneic oxygenation
Authors: Anthonisen Nicholas R.
Published: December 2017

Open-chested denitrogenated cats were studied during 30-min periods of apneic oxygenation. Two lung volumes were selected, one about 25% of total lung capacity (TLC), and the other one about 55% of TLC. Serial measurements were made during apnea of pulmonary shunt flow (Qs/Qt) and static pulmonary compliance (Cl). Lung volumes were measured at the beginning and end of the period of apnea. Apneic oxygenation at 25% TLC regularly was associated with increasing Qs/Qt, decreasing Cl, and loss of lung volume signifying atelectasis. None of these phenomena were observed at 55% TLC. These results are discussed as they relate to time-dependent changes in the surface characteristics of the alveolar lining.
Electrical changes in brain and eye of developing chick during hyperthermia
Authors: Peters Joseph J. , Vonderahe Alphonse R. , McDonough John J.
Published: December 2017

As the body temperature of chicks between the day of hatching and the 3rd week after hatching was raised from normal to approximately 44.5 C, the eye was subjected to periodic photic stimulation while electrical recordings were taken from the eye and cerebral and optic lobes. As body temperature rose, the cerebrum showed an increased percentage of low-voltage fast waves mainly in the older birds, then sequences of slow waves of large amplitude, and finally a disappearance of spontaneous electrical activity, even though an electrocardiogram persisted for several minutes longer. During photic stimulation and hyperthermia, at the optic lobes the "flash-for-flash" response disappeared first, and then the "on" response, followed by a loss of the electroretinogram at the eye. Under the influence of hyperthermia, electrical activity of brain and eye persisted longest in the newly hatched chicks, and in them there appeared a slow spike and wave pattern probably associated with brain damage.
Adrenergic innervation of cat iris sphincter
Authors: Schaeppi U. , Koella W. P.
Published: December 2017

Isometric tension changes of the iris sphincter of the cat were investigated in vitro. Electrical stimulation resulted in contraction followed by relaxation. Elimination of the cholinergic component by chronic parasympathetic denervation or by atropine, or both, markedly reduced electrically induced contraction, but had little influence on relaxation. Norepinephrine produced contraction, relaxation, or slight relaxation followed by contraction. Isoproterenol elicited virtually pure relaxation. The actions of dichloroisoproterenol and phentolamine indicated that relaxation induced electrically or by drug was due mainly to activation of beta receptors and contraction was due to activation of alpha receptors. Proper choice of electrical stimulus parameters (high versus low stimulus rate) allowed activation predominantly of relaxing beta adrenergic, or of contractile alpha adrenergic mechanisms, respectively. These studies also confirm earlier observations that electrical stimuli act indirectly, i.e., via excitation of nerve terminals and release of transmitter, and that the sphincter muscle is not directly excitable by electrical shocks.
Effect of electrical stimulation of telencephalon on ovulation and oviposition in the hen
Authors: Juhasz L. P. , Tienhoven A. Van
Published: December 2017

Electrical stimulation of the archistriatum and paleostriatum primitivum leads to a 2- to 4-hr delay of ovulation and generally to a delay of 2–48 hr of oviposition in White Leghorn hens. The optimal time for stimulation for obtaining these effects is 13–16 hr before ovulation. Electrical stimulation of the neostriatum, area septalis, or of the paleostriatum augmentatum affects neither ovulation nor oviposition. Possible explanations are offered for the effects observed.
Analysis of QRS complex recorded through a semiorthogonal lead system in the horse
Authors: Hamlin Robert L. , Smetzer David L. , Smith C. Roger
Published: December 2017

A semiorthogonal lead system for recording electrocardiograms from horses was designed. The X, Y, and Z axes of the body were monitored by leads I, aVF, and V10 (the unipolar lead taken from the dorsal spinous process of the seventh thoracic vertebra), respectively. Records were taken from 15 standing horses. Ventricular premature beats were elicited by pricking foci on the right and left ventricular epicardium. For normally conducted beats, two major vectors represented forces generating the QRS complex. Vector 1, probably representing excitation of the apical third of the interventricular septum from left to right, was relatively low in magnitude, and was oriented dextrad, ventrad, and craniad. Vector 2, probably representing depolarization of the basilar third of the interventricular septum from left to right and in an apicobasilar direction, was of greater magnitude and was oriented ventrad, sinistrad, and craniad. Occasionally a vector intermediate between vectors 1 and 2 was oriented caudad and dorsad. The origin of this vector is equivocal. Left ventricular premature beats generated vectors of great magnitude oriented dextrad and craniad. Right ventricular premature beats generated vectors of magnitude between those of sinus or left ventricular origin, and directed predominantly sinistrad.
Metabolic effects of ouabain in the perfused rat heart
Authors: Kreisberg Robert A. , Williamson John R.
Published: December 2017

Ouabain increased the uptake and oxidation of glucose-U-C14 by perfused guinea pig and rat hearts by 50%. Cardiac glycogen content remained constant and no change in glycogen specific activity was observed. The metabolic changes produced by ouabain were dependent on the calcium concentration of the perfusate. Reduction of the calcium content of the perfusate by 50% abolished the increase in C14O2 production by ouabain. The C14O2 production of hearts perfused with buffer containing twice the physiological calcium concentration was similar to that of hearts perfused with buffer containing the normal calcium concentration and ouabain. The effect of the high calcium concentration combined with ouabain was not different from that produced by either one alone. Steady-state levels of glycolytic intermediates after a 30-min perfusion period were elevated in the absence of glycogenolysis and free glucose did not accumulate intracellularly. In so far as the changes in glucose metabolism are concerned the findings are consistent with the concept that the effects of glycosides on cardiac muscle are dependent on changes in calcium transport or concentration at the site of the contractile elements.
Serum enzyme activities in endotoxin shock
Authors: Konttinen A. , Rajasalmi M. , Paloheimo J.
Published: December 2017

The glutamic oxalacetic transaminase (GOT), lactic dehydrogenase (LDH), α-hydroxybutyric dehydrogenase (HBD), and creatine phosphokinase (CPK) activities in the serum of 13 rabbits have been studied upon intravenous Escherichia coli endotoxin administration. The systolic blood pressure and the rectal temperature of the animals were recorded at each blood sampling. A prompt rise of the serum GOT, LDH, and HBD activities occurred, that of the serum GOT being the most marked. No increase of serum CPK activity during the shock was noted. The observed elevations subsided within 48 hr after endotoxin administration. The liver is suggested as the most likely point of enzyme release into the blood; the effect might be caused by tissue hypoxia coupled with catecholamine leakage.
Serum enzymes and lactic dehydrogenase isoenzymes after exercise and training in rats
Authors: Garbus Joel , Highman Benjamin , Altland Paul D.
Published: December 2017

After 16 hr exercise, untrained rats, in contrast to exercise-trained rats, show a marked rise in serum lactic dehydrogenase, aldolase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, and urea nitrogen. Electrophoretic studies reveal abnormal serum isoenzyme patterns indicating that excess lactic dehydrogenase is derived not only from muscle, but also from heart and probably other organs. Histopathologic studies and serum transaminase ratios support this conclusion. These findings are correlated with necrosis in muscle fibers and fatty changes in muscle, heart, and other organs of untrained rats after prolonged exercise and the absence of such changes in similarly exercise-trained animals. Alterations in cellular permeability best explain the rise in serum enzymes. However, exercise training does not prevent pathologic and serum enzyme and isoenzyme changes induced by epinephrine in oil. Moreover, the adrenergic blocking agent, Dibenamine, which ameliorates such changes induced by epinephrine or hypoxia, does not mitigate the effects of prolonged exercise in untrained rats. These findings suggest that the permeability changes induced by prolonged exercise are not due merely to the effects of hypoxia or of catecholamines released from the adrenal medulla, but are different and perhaps specific.
Comparison of permeability of different layers of the primate placenta to d-arabinose and urea
Authors: Battaglia Frederick C. , Bruns Paul D. , Behrman Richard E. , Seeds A. Elmore , Hellegers Andre E.
Published: December 2017

The permeability of the amnion, chorion, and chorioamnion of the rhesus monkey placenta to urea and to d-arabinose has been studied in vitro. The chorion and chorioamnion were found to be less permeable per unit area than the amnion. No change in permeability with gestational age was found in each of the three tissue layers. Comparison with permeability data for the human chorion laeve revealed the permeability of the rhesus chorion to be similar in magnitude. All three tissue layers studied were more permeable to urea than to d-arabinose.
Binding of calcium ions to cell membrane isolated from bullfrog skeletal muscle
Authors: Koketsu K. , Kitamura R. , Tanaka R.
Published: December 2017

The membrane fragments of bullfrog skeletal muscle fibers were isolated by a modification of the method of Kono and Colowick (1961). Radiocalcium ions were bound to these isolated membrane fragments, and the binding of calcium ions was impeded by both sodium and potassium ions. The extractable portion of the isolated membrane fragments with chloroform-methanol mixture bound calcium ions whereas no appreciable binding of calcium ions was observed with the extracted residue. The results suggested that the binding of calcium ions takes place on the lipid or lipoprotein of the so-called cytoplasmic membrane which plays an important role in regulating the membrane permeability and the membrane potential.
Effect of acute changes in left atrial pressure on urine flow in unanesthetized dogs
Authors: Lydtin Helmut , Hamilton William F.
Published: December 2017

The effect of an acute rise in left atrial pressure on urine flow, urine specific gravity, and sodium excretion was studied in chronic preparations with and without anesthesia and at different hydration levels. Left atrial pressure was changed by an exteriorized purse string about the mitral annulus. In 56 of 58 experiments (including each of the above conditions) a transient increase of urine flow was found during atrial distention, accompanied by an increase in sodium excretion and a fall in urine specific gravity. Absolute volume and percentage increase of the diuresis varied directly with the degree of prehydration. Vasopressin infusions modified the response only in prehydrated animals. Arterial pressure and renal blood flow (electromagnetic flowmeter) were increased during atrial distention. At least two mechanisms interplay in the diuretic response: 1) hemodynamic and 2) humoral (ADH or Jahn's "diuretic factor"). The degree of prehydration seems to determine the threshold of the ADH mechanism. Our data speak against homeostatic fluid volume control by stretch receptors in the left atrium or its inflow tract.
Stimulation of sodium transport in toad bladder by acidification of mucosal medium
Authors: Leaf Alexander , Keller Albert , Dempsey Eleanor F.
Published: December 2017

The short-circuit current, sodium flux, and electrical potential across the isolated urinary bladder of the toad were stimulated by acidification of the medium bathing the mucosal or urinary surface of the bladder. By contrast the transport of chloride, potassium, urea, and water across the bladder was unaffected by similar acidification. The pH optimum for this action was approximately 5.5. The tissue pH, as determined by the distribution of DMO-C14, was not detectably affected by mucosal acidification.
Serum cholesterol levels of inbred rats
Authors: Kritchevsky David , Tepper Shirley A.
Published: December 2017

Changes in serum cholesterol levels with age have been studied in male and female rats of three inbred strains (BN, DA, and Lewis) and one random-bred strain (Wistar). The mean serum cholesterol levels at each age differed among strains. Serum cholesterol levels (mg/100 ml) for male rats at 30, 60, and 90 days were: BN-65, 46, and 47; DA-105, 85, and 101; Lewis-79, 76, and 57; and Wistar-64, 63, and 73. For female rats the values were: BN-56, 45, and 47; DA-86, 74, and 91; Lewis-77, 83, and 67; and Wistar-59, 71, and 83. The variation of serum cholesterol with age was different between strains, but similar for males and females within each strain. There was no correlation between body weight and serum cholesterol. Liver cholesterol levels (mg/100 g) determined at 90 days were, for the males, BN-187, DA-233, Lewis-247, and Wistar-300, and for the females, BN-188, DA-244, Lewis-216, and Wistar-249. No correlation with body weight or serum cholesterol was observed.
Effect of osmolar loading on stimulated gastric secretion in the dog
Authors: Powell Don W. , Hirschowitz Basil I.
Published: December 2017

A study was made of the effects of intravenous infusions of 100-ml hypertonic (ca. 2,400 mosmoles/kg) solutions of NaCl, mannitol, and glucose on blood and gastric juice of five dogs during histamine stimulation. These were compared to control studies in the same dogs in which no infusion was given or in which isotonic NaCl was infused. Hypertonic solutions, regardless of chemical nature, acutely elevated plasma osmolality by 18–24 mosmoles/kg, raised gastric juice [H+] by 7–10 mEq/liter and [Cl–] by 6–9 mEq/liter. The output of volume, H+, Cl–, and pepsin, however, was unaffected. In the light of these findings the osmolality of the gastric mucosa is judged to be isotonic with plasma and extremely sensitive to external osmotic changes.