bluuebunny/crossref_metadata_2025 huggingface dataset:
Maximal acid secretory response to histamine and its relation to parietal cell mass in the dog
Authors: Marks I. N. , Komarov S. A. , Shay Harry
Published: December 2017

Gastric secretion in response to graded doses of histamine was obtained from the whole stomach in five trained dogs, and the animals were sacrificed to determine the total number of parietal cells in the stomach. Histamine was administered by single s.c. injection (Hsc) and continuous i.v. infusion (Hiv). Maximal histamine response (MHR) was determined, and studies permitting the construction of dose-response curves were carried out in three of the five dogs. Dose-response curves for acidity and for acid output and volume during the entire duration of secretory response to Hsc were also established. The MHR was found to be a linear function of both the total number of parietal cells ( P < .01) and the fundic mucosal volume ( P < .05). The magnitude of the MHR and the PCM in the five dogs was within the respective ranges reported in man, but the mean MHR per billion cells (9.8 ± 0.44 mEq/30 min.) and the mean MHR per 100 cc fundic mucosal volume (58.2 ± 5.12 mEq/30 min.) were both about 30% less than the respective ratios in man.
Role of the kidney in erythropoiesis
Authors: Suki Wadi , Grollman Arthur
Published: December 2017

There was a marked reduction in erythropoiesis and hemoglobin synthesis in the nephrectomized dog as compared to the normal intact animal even when azotemia was reduced to a low level by intermittent peritoneal lavage. Dogs with a ureterovenous anastomosis maintained in a similar manner showed a normal rate of erythropoiesis, as measured by radioiron uptake. It is concluded, therefore, that the kidney is the site of formation of an erythrocyte stimulating factor essential for the maintenance of normal erythropoiesis. That this factor is of humoral nature was demonstrated by the erythropoietic stimulating action of renal extracts.
Relation of leukocyte and fever responses to bacterial endotoxin
Authors: Herion John C. , Walker Richard I. , Palmer Jeffress G.
Published: December 2017

Administration of typhoid vaccine or purified bacterial endotoxin produced leukopenia maximal at 50–60 minutes, followed by a second drop or plateau at 120–140 minutes. These changes were parallel to the known biphasic response and were noted in both capillary and venous blood. The initial decrease affects both granulocytes and lymphocytes; subsequent leukocytosis was due to granulocytosis. Anesthesia abolished the febrile response but did not affect the leukocyte changes. Repeated daily administration of endotoxin produced febrile tolerance characterized predominantly by loss of the second peak with shortening of duration of fever. A similar shortening of duration of leukopenia was noted with development of tolerance. Brief monophasic fever and leukopenia also was noted when a second dose was given 6 hours after the first. These observations support the concept of the central role of leukocytes in endotoxin fever, and suggest that changes in the ability of leukocytes to release pyrogen are concerned with the mechanism of febrile tolerance.
Interrelations between actions of parathyroid hormone and estrogens on bone and blood in avian species
Authors: Urist Marshall R. , Deutsch Nancy M. , Pomerantz George , McLean Franklin C.
Published: December 2017

The level of calcium was measured in whole serum and ultrafiltrates of serum of roosters and laying hens following parathyroidectomy or after treatment with parathyroid extract, and in the presence or absence of the effects of endogenous or exogenous estrogens. The results were correlated with changes in: a) the weight of various endocrine organs influencing calcium metabolism in avian species, and b) microradiographic and histologic sections of the bones. The parathyroid hormone and estrogen had an additive effect upon the serum calcium, rather than a synergistic action. The effect of each hormone was readily distinguished by the interpretation that while ultrafilterable calcium was under parathyroid control, the large increase in the nonultrafilterable fraction under the influence of estrogen depended upon the formation of a calcium phosphoproteinate complex the liver. Under all conditions, the interrelations between the ultrafilterable and the nonultrafilterable fractions of the serum calcium were those dependent upon a mass-law equilibrium.
Transport of monovalent cations by the isolated small intestine of the rat
Authors: Clarkson T. W. , Rothstein A.
Published: December 2017

Everted segments of the small intestine of the rat, taken from both jejunal and ileal regions, were able to transport sodium against an electrochemical gradient by a highly specific mechanism. Other monovalent cations (cesium, potassium, lithium and triethylammonium) moved across the tissue much more slowly than sodium and always in the direction of the electrochemical gradient. Water movement appeared to be passive following the osmotic forces set up by active solute transfer. Both the electrical potential difference across the tissue and the net water transfer fell rapidly when the sodium concentrations in the media were reduced below 120 mm/l. Glucose transport was also responsive to the cation composition of the media; low concentrations of sodium were inhibitory, lithium at 25 mm/l. produced a stimulatory effect, and potassium at 25 mm/l. was inhibitory.
Flow rate of urine as a determinant of renal countercurrent multiplier system
Authors: Abbrecht Peter H. , Malvin Richard L.
Published: December 2017

The mathematical treatment of the renal countercurrent multiplier system predicts that the rates of flow of urine and blood through the medullary loops are determinants of the maximal osmolarity which may be established in the medullary interstitium. It was found that acute increases in the urine flow rate resulted in a concomitant increase in the sodium concentration of the urine. The relation between urine flow rates and urine osmolarity was studied more closely. During osmotic diuresis the GFR of one kidney was reduced independently of the renal plasma flow by partially occluding one ureteral catheter. This resulted in an increase in urine osmolarity from that kidney. The increase in urine osmolarity correlated with an increase in the medullary sodium gradient. A smooth curve was obtained relating urine osmolarity to percent reduction of GFR. Urine osmolarity increased as the GFR was reduced, reaching a maximum at 70% reduction in GFR. Greater reductions of GFR resulted in decreasing osmolarities.
Body glucose as fuel for thermogenesis in the white rat exposed to cold
Authors: Depocas Florent , Masironi Roberto
Published: December 2017

Various parameters of glucose metabolism were measured with C14-glucose in unanesthetized warm- and cold-acclimated rats at 30° and 6°C. Exposure of warm-acclimated rats to cold was associated with a decrease in turnover time of plasma glucose, no change in glucose pool size and space, an increase in rates of turnover and oxidation of body glucose, an increase in the ratio of the oxidation rate to the turnover rate, no change in percentage of respiratory CO2 derived from glucose oxidation, and a decrease in liver glycogen content. Approximately reversed changes were observed in cold-acclimated rats transferred from a cold to a warm environment except in the values of turnover time of plasma glucose and terminal liver glycogen content which underwent smaller changes. It is concluded that cold-induced thermogenesis in white rats, whether acclimated to warm or cold environments, is associated with an increase in carbohydrate catabolism proportionate to the increase in energy metabolism.
Effects of chlorpromazine on mammary glands of rats
Authors: Talwalker P. K. , Meites J. , Nicoll C. S. , Hopkins T. F.
Published: December 2017

The effects of chlorpromazine were determined on mammary growth and initiation of milk secretion in virgin rats, and on maintenance of mammary structure and secretion in postpartum rats after litter removal. When chlorpromazine was administered in doses of 5 or 15 mg/kg body weight for 5 days, only the higher dose was effective in inducing lobulo-alveolar growth and initiating milk secretion in rats initially primed with 10 µg estradiol daily for 10 days. The higher dose of chlorpromazine also maintained mammary lobulo-alveolar structure and secretion in post-partum rats for 10 days after litter removal. Chlorpromazine produced a significant increase in adrenal weight and decrease in thymus weight, indicating adrenal stimulation. In estrogen-primed rats neither prolactin nor ACTH alone could initiate mammary secretion; however they were effective when given in combination. The present data indicate that chlorpromazine promotes the secretion of both prolactin and ACTH. Hypophysectomy following estradiol treatment prevented chlorpromazine from initiating mammary secretion, showing that its effects are mediated through the anterior pituitary and not directly on the mammary gland.
Tubular secretion of urate in the dog
Authors: Yü Ts'ai Fan , Berger Lawrence , Kupfer Sherman , Gutman Alexander B.
Published: December 2017

Clearance studies under appropriate conditions of urate loading and osmotic diuresis yielded Curate/GFR ratios > 1.10 in both Dalmatian and non-Dalmatian dogs, indicating tubular secretion of urate. In the purebred Dalmatian, stop-flow studies (U/Purate: U/Pcreatinine ratios) localized peak net urate secretion to the proximal segment, with a second, lesser peak in the distal segment. Both peaks were abolished by probenecid and, in massive dosage, by PAH, yielding ratios < 1. In the mongrel dog, stop-flow studies showed maximal net tubular reabsorption of urate in the proximal segment, peak net tubular secretion of urate in the distal segment. Proximal urate secretion was not demonstrated but may have been masked by preponderant urate reabsorption. It is suggested that, as in man, renal regulation of urate excretion in the dog involves glomerular filtration, tubular reabsorption (deficient but still demonstrable in the Dalmatian) and tubular secretion (ordinarily masked by preponderant reabsorption in the non-Dalmatian). Both reabsorption and secretion of urate in the dog appear to be effected largely by ‘active’ processes.
Serum enzyme rise after hypoxia and effect of autonomic blockade
Authors: Highman Benjamin , Altland Paul D.
Published: December 2017

Dogs exposed for 4 hours to a simulated altitude of 32,000 feet showed hyperglycemia and a sharp rise in serum glutamic oxalacetic transaminase (SGO-T), serum glutamic pyruvic transaminase (SGP-T), serum lactic dehydrogenase (SLD), and serum alkaline phosphatase (SAk-P). Hyperglycemia reached a peak in about 6 hours and subsided within 24 hours. Other elevations reached a peak in 6–24 hours and subsided in 3–7 days. The increases in SGO-T, SGP-T and SLD were diminished by the adrenergic blocking agent phenoxybenzamine (Dibenzyline) and the hyperglycemia by the ganglionic blocking agent chlorisondamine dimethochloride (Ecolid). These findings support the view that high altitude hypoxia causes hyperglycemia by releasing catecholamines from the adrenal medulla and increases certain serum enzyme values by increasing selectively cellular permeability to such enzymes. Pretreatment with epinephrine-in-oil before an exposure greatly increased the serum enzyme rise at 24 hours but diminished the 6-hour rise of SGO-T; this suggests partial inactivation of some serum enzymes by an excess of metabolites associated with hypoxia and/or epinephrine.
Free fatty acid metabolism in fetal and newborn sheep
Authors: Duyne C. M. Van , Parker H. R. , Havel R. J. , Holm L. W.
Published: December 2017

The metabolism of free fatty acids (FFA) was studied in the term ewe, sheep fetus and newborn lamb. The concentration of FFA is about 10 times greater and the concentration of triglyceride fatty acids (TGFA) 2 1/2 times greater in maternal than in fetal plasma. After intravascular administration of palmitic acid-1-C14 complexed to homologous albumin, the initial rates of disappearance of FFA radioactivity from maternal and fetal circulations were similar, with half-times of approximately 2 minutes. Radioactivity appeared in the opposite circulation as FFA indicating that the syndesmochorial placenta is permeable to palmitic acid. Survival of the newborn lamb is associated with a fivefold increase in plasma concentration of FFA and no significant change in glucose or fructose during the first 30 minutes after birth. Failure to survive is associated with lack of increase in plasma FFA concentrations, while glucose concentrations do not differ from those found in surviving lambs. These data suggest that sympathetic nervous system activity is responsible for the FFA elevation and that increased activity of the sympathetic nervous system or FFA mobilization is closely related to survival of the newborn lamb.
Biochemical changes and increased liver weight in bone marrow chimeras
Authors: Kretchmar A. L. , Congdon C. C.
Published: December 2017

Female mice of two different strains were x-irradiated (950 or 900 r total-body) and then given 40 x 106 bone marrow cells from the same or a different strain of female donor mice. Irradiated mice lost weight during the 1st week after treatment. Mice given bone marrow cells showed good recovery except that when the cells were from a different strain there was a second weight loss persisting to the 35th day. The liver weight increased after treatment. The maximum was noted at 12 days. Glutamine and glutathione concentration in livers of treated mice was reduced at 12 days and the concentration of ß-aminoisobutyric acid and of ß-alanine was increased. The changes were greatest in animals given bone marrow cells of a different strain.
Separation of cardioaccelerator and coronary vasomotor fibers in the dog
Authors: Juhasz-Nagy A. , Szentivanyi M.
Published: December 2017

In the dog the preganglionic ‘B’ fibers in the accelerator nerve that synapse with intracardiac adrenergic or cholinergic neurons are the vasomotor fibers of the coronaries. Stimulation of the coronary constrictors produces a reduction of flow, but the O2 consumption of the heart does not change. The A-V O2 difference and the A-V lactate difference increase proportionately indicating that no change takes place in the metabolic pattern. Stimulation of the postganglionic cardioaccelerator fibers increases blood pressure, coronary flow and O2 consumption, the A-V lactate difference increases or decreases. The metabolic pattern is also altered. A true vasomotor dilatation (no change in the metabolic pattern) can also be induced in the dog. These fibers are cholinergic in nature. The vagus plays no role in the innervation of the coronaries in the dog.
TAMe esterase activity resulting from blood thromboplastin formation
Authors: Koppel J. L. , Hough Dorothy Mueller , Arscott Phyllis M. , Olwin John H.
Published: December 2017

TAMe esterase activity levels have been determined on a) purified coagulation factors essential for thromboplastin (TPN) formation, b) various intermediate products formed in the presence of calcium and phospholipid, and c) complete blood thromboplastin. The level of esterase activity was found to increase as TPN formation proceeded through various intermediate stages to the final active product. The esterase activities of intermediate products I and II were practically completely inhibited by soybean trypsin inhibitor (SBTI), whereas that of blood thromboplastin was inhibited only partially. Interaction of product II with plasma Ac-globulin resulted in the most marked increase in esterase activity. The observations made suggest that this increased and SBTI-insensitive activity is not due to the presence of either thrombin or serum Ac-globulin (factor VI). It has been concluded that the observed TAMe esterase activity is due to blood thromboplastin itself and that the latter resembles Milstone's thrombokinase.
Renal action of acetazolamide in extracellular alkalosis of K+ deficiency
Authors: Maren Thomas H. , Sorsdahl Oliver A. , Dickhaus Alfred J.
Published: December 2017

Acetazolamide was tested in the extracellular alkalosis of K+ depletion, a metabolic situation which presumably elicits a general intracellular acidosis, demonstrated for both muscle and kidney. The renal effect of drug on HCO3– excretion was markedly less than normal despite elevated plasma HCO3– concentration. These experiments, together with those on metabolic and respiratory acidosis, suggest that with decreased intracellular renal pH, the role of carbonic anhydrase in renal acidification and HCO3– reabsorption is reduced.
Oxidative metabolism of incubated cerebral cortex slices from pyridoxine-deficient kittens
Authors: McKhann Guy M. , Mickelsen Olaf , Tower Donald B.
Published: December 2017

Pyridoxine deficiency was produced in weanling kittens by dietary means. Clinically, the deficient animals showed failure to gain weight, ataxia, and, if left on the diet, seizures and death. In vitro study of isolated cerebral cortex slices from the deficient animals showed decreased formation of γ-aminobutyric acid and decreased oxygen uptake when glucose was the substrate. Addition of pyridoxal phosphate to the incubation media corrected both of these defects toward the levels found in normal littermate controls. The decreased oxygen uptake was also corrected by the addition of γ-aminobutyric acid to the media. It is suggested that in pyridoxine deficiency, cerebral oxidative metabolism is impaired by blockage of the γ-aminobutyric acid ‘shunt’ pathway at the glutamic decarboxylase step. The role of this shunt pathway in normal neuronal metabolism is discussed.
Effect of thiouracil on liver enlargement in tumor-bearing rats
Authors: Girkin Gene , Kampschmidt Ralph F.
Published: December 2017

It is well known that the liver of animals bearing the Walker carcinosarcoma 256 enlarges during tumor growth. The effect of thiouracil administration and thyroidectomy on this hypertrophy was studied. Thiouracil administration prevented the usual liver enlargement in animals bearing the Walker tumor as well as the enlargement produced by toxohormone prepared from this tumor. Thyroidectomy also prevented an increase in liver mass in tumor-bearing animals. The effect of thiouracil on liver enlargement in tumor-bearing rats could be largely overcome by thyroxine supplementation. Liver regeneration was strikingly inhibited in partially hepatectomized tumor-bearing rats treated with thiouracil. A significant inhibition of regeneration was also noted in control animals receiving thiouracil.
Cholinergic-like effects of hypertonic solutions
Authors: Read Raymond C. , Vick J. A.
Published: December 2017

A consideration of the physiological effects of hypertonic solutions suggested that certain aspects might be cholinergic. This hypothesis has been investigated. Concentrated urea, glucose or salt solutions were rapidly injected intravenously into 25 anesthetized dogs. Systemic and pulmonary vascular pressures were monitored and compared with those obtained with acetylcholine. Data were collected before and after cervical vagotomy or treatment with physostigmine or atropine. The effects of hyperosmotic media and acetylcholine were similar. Both, in lower concentrations, produced transitory vasodilatation; bradycardia and cardiac irregularities became superimposed with stronger solutions. However, the hypertonic phenomena were ameliorated by vagotomy, unaffected by atropine and only partially potentiated by Eserine. Vasodilatation required a latent period of about 10 seconds beyond the circulation time. The evidence suggests that hypertonic materials evoke release of acetylcholine as a result of reflex and central nervous excitation. In addition, they exert a direct cholinergic-like action, mediated possibly through depolarization of cholinergically innervated effector cells from osmotic dehydration.
Effects of adrenergic blocking agents on plasma free fatty acid concentrations
Authors: McElroy William T. , Spitzer John J.
Published: December 2017

To blockade tonic sympathetic influences on FFA (free fatty acids) plasma concentrations, or responses by adipose tissue to administered amines, dogs received Dibenzyline, Dibenamine, ergotamine or trimethaphan. Plasma FFA and glucose in femoral vessels and hepatic and portal veins were determined. Estimated hepatic plasma flow (EHPF) and mean blood pressures were recorded. Unanesthetized, untreated dogs often showed FFA responses to injected amines that were quantitatively different from previous testing. FFA responses in anesthetized animals were more reproducible. Dibenzyline elevated FFA and glucose levels and lowered blood pressure. Trimethaphan elevated FFA concentrations and decreased EHPF, glucose and blood pressure. Ergotamine decreased FFA, blood pressure and EHPF. Dibenzyline or Dibenamine failed to block glucose or FFA responses to injected catecholamines, but ergotamine usually decreased hyperglycemic and occasionally FFA responses. Trimethaphan did not prevent FFA or glucose changes in dogs made hypercapnic. Like the hyperglycemic response, FFA release by adipose tissue is difficult to block even with large doses of blocking agents.
Pyridine nucleotide oxidases and transhydrogenase in acclimatization to high altitude
Authors: D. Baltazar Reynafarje
Published: December 2017

Activities of pyridine nucleotide oxidases and transhydrogenase have been examined in heart, liver and rectus femoris muscle of guinea pigs native to sea level and high altitude. There was found an enhanced reduced form of diphosphopyridine nucleotide oxidase (DPNH-oxidase) and transhydrogenase activity in heart and muscle from animals adapted to high altitude. In muscle the higher activity at altitude was due solely to increase in ratio of red to white portions. Both groups showed the pigmented portion twice as active as the white one. In liver, neither the DPNH-oxidase system nor the transhydrogenase were significantly changed in their activities on a fresh weight basis. Nevertheless, the DPNH-oxidase is higher at altitude when the activity is expressed per gram of nitrogen. The reduced form of triphosphopyridine nucleotide oxidase activity was not appreciably changed in any of the studied tissues. It was concluded that adaptation to high altitude is associated with apparent changes in the magnitude of the electron transport pathway. Increased activity in skeletal muscle is probably related to the tissue pigment content.
Interactions of amino acids in renal tubular transport
Authors: Webber W. A. , Brown J. L. , Pitts R. F.
Published: December 2017

The effects of intravenous infusions of l-lysine, l-arginine, l-histidine, l-ornithine and l-cysteine at three rates on the plasma levels and excretions of naturally occurring amino acids were studied in dogs. Conventional clearance techniques were used, and the amino acid concentrations in both plasma and urine were determined by column chromatography. A number of changes were observed in plasma amino acid concentrations, the most striking of which was a 20-fold increase in ornithine following arginine infusion. This increase is probably the result of conversion of arginine to ornithine via the Krebs-Henseleit cycle. Lysine, ornithine, arginine and cystine or cysteine showed marked mutual inhibition of tubular reabsorption. Histidine modestly inhibited reabsorption of these amino acids, and in turn its reabsorption was modestly depressed by them. The basic amino acid infusions also caused modest depression of the reabsorption of glycine and slight depression of that of several other amino acids. The reabsorptive mechanisms for lysine, arginine, ornithine and cystine are closely related and may be identical. There is, however, minor reabsorptive competition between these amino acids and certain others, suggesting that the mechanisms are not completely specific.
Pressure-flow relationships in isolated canine cerebral circulation
Authors: Sagawa Kiichi , Guyton Arthur C.
Published: December 2017

As a result of anatomic studies on the cerebral arteries and veins in the dog using vascular cast preparations, a surgical procedure was developed by which a) the cerebral arterial circulation can be completely isolated from the systemic circulation and b) the perfusion blood will flow only to the intracranial regions. Also devised was a servomechanism which controls the donor dog's body weight and thus prevents a blood volume shift between the donor and recipient dogs, within ± 5 cc of the original value. The cerebral perfusion pressure (C.P.P.) was controlled by a Starling's resistance and was altered stepwise from 140 to 0 mm Hg. At each C.P.P. level the cerebral blood flow (C.B.F.) was measured by a stromuhr. The mean and the standard deviation of C.B.F. values at 100 mm Hg C.P.P. in 10 dogs was 67.1 ± 19.5 cc/100 gm brain/min. Pressure-flow relationship over the C.P.P. range from 140 to 0 mm Hg did not show any evidence of autoregulation of the cerebral vessels, but instead suggested a linear proportional relationship.
Mechanism of renal potassium secretion studied by a modified stop-flow technique
Authors: Walker W. Gordon , Cooke C. Robert , Payne John W. , Baker C. Richard F. , Andrew David J.
Published: December 2017

The distal K-secreting mechanism of the kidney was studied by the stop-flow technique. With the original technique, maximal K secretion was demonstrated in the first 3 ml collected after occlusion. In adjacent proximal samples K and Na declined to minimum values and then returned to free-flow values. To study the relation between K secretion and luminal Na concentration at the K secretory site, the technique was modified by collecting only 3 ml after the first occlusion and then reoccluding. This permitted urine containing maximum K concentration to escape and allowed fluid quite low in sodium to move down to the K secretory site. Samples collected following the second occlusion regularly failed to show any distal K peak. If 8 ml were collected between occlusions, the fluid containing the Na and K minima was also collected, and Na concentration once again was raised at the K secretory site. This resulted in peak K concentrations following the second occlusion that were indistinguishable from the first. These are the findings expected for a K-for-Na ion exchange mechanism for distal K secretion. Coincidence of Na and K minima may be explained on this basis.
Micropuncture study of net transtubular movement of water and urea in nondiuretic mammalian kidney
Authors: Lassiter William E. , Gottschalk Carl W. , Mylle Margaret
Published: December 2017

Anesthetized, nondiuretic rats and hamsters were infused with C14-labeled inulin-carboxylic acid or urea, and fluid was subsequently collected by micropuncture from surface tubules in the rats and from loops of Henle and collecting ducts in the hamsters. Osmolality and radioactivity of tubular fluid, ureteral urine, and plasma were determined. There was net loss of both water and solute from all segments of the nephron. In the loop of Henle, water loss occurred primarily from the descending limb and solute loss from the ascending limb. Urea was reabsorbed from the proximal and distal convolutions and collecting ducts but was added to the tubular fluid in the descending limb of the loop of Henle. These results lend support to the countercurrent theory of urine concentration and indicate that the osmotic gradient in the medulla is established by active transport of solute out of the ascending limb of the loop of Henle. The results are compatible with passive movement of water and urea, but the possibility of active transport of urea is not excluded.
Quantitative importance of plasma glucose for synthesis of milk fat glycerol
Authors: Luick Jack R. , Kleiber Max
Published: December 2017

A study was made of the relationship between plasma glucose and milk fat glycerol following the injection of U-C14 glucose into four lactating cows. We have shown that plasma glucose contributes more than 70% of the C required for glycerol synthesis. The metabolic pathways by which circulating glucose C might be incorporated into glycerol were discussed.
Liver injury in isolated perfused rat liver preparation exposed to chloroform
Authors: Brauer R. W. , Leong G. F. , Holloway R. J.
Published: December 2017

Page 548: R. W. Brauer, G. F. Leong and R. J. Holloway, "Liver injury in isolated perfused rat liver preparation exposed to chloroform." Through an unfortunate oversight, throughout the text and figures, chloroform concentrations are referred to in terms of milligrams per liter instead of the correct unit of grams per liter. Thus, the chloroform levels employed and illustrated, for instance, in figure 2 should read 0.016 g/liter, etc.
Pharmacological evidence for active reflex dilatation
Authors: Sakuma Akira , Beck Lloyd
Published: December 2017

Pharmacological evidence for the existence of active reflex dilatation has been obtained by the use of agents which prevent the release of norepinephrine. Similar conclusions have been reached using an amine oxidase inhibitor to slow the rate of degradation of norepinephrine. The contribution of the active and passive components to the total reflex dilatation has been assessed. It is concluded that active reflex dilatation occurs in response to the intravenous injection of epinephrine or norepinephrine and that the reflex may be principally active even when a high level of sympathetic tone exists.
Hemodynamic effects of angiotensin, norepinephrine, and bradykinin continuously measured in unanesthetized dogs
Authors: Page Irvine H. , Olmsted Frederick
Published: December 2017

Cardiac output, arterial pressure, heart rate and the derived functions, peripheral resistance and stroke volume, were registered continuously from intact, unanesthetized, unrestrained dogs. Isoleucyl5- or valyl5-angiotensin octapeptide caused output, heart rate and stroke volume to fall sharply when peripheral resistance rose. When infused for an hour, systolic and diastolic pressure remained elevated with unchanged infusion rate. Heart rate decreased in most animals, stroke volume and cardiac output fell, while peripheral resistance rose. Pentobarbital anesthesia increased somewhat the pressor response and decreased the bradycardia. Norepinephrine elicited, first, an abrupt rise in pressure and peripheral resistance, slight rise in heart rate and stroke volume. Arterial pressure then tended to stabilize, followed by a slow decrease associated with continued depression of cardiac output. Bradykinin caused fall in pressure, partial recovery, then further fall. Heart rate slowed, then rose. Cardiac output rose sharply during the initial fall in arterial pressure and remained elevated during the hypotensive response. Stroke volume was reduced during the initial fall but was reduced less during the rest of the response. Peripheral resistance was decreased sharply.
Active transport of C14-d-glucose by turtle small intestine
Authors: Fox Sister Alice Marie
Published: December 2017

An in vitro preparation was used to demonstrate that C14-d-glucose is taken up at the mucosal surface of turtle small intestine at 30 C. Movement of the sugar across the intestinal tissues and its release into the serosal fluid against an apparent concentration difference was shown. The source of the sugar entering the medium on the serosal side appeared to be, in part, the glucose taken up from the mucosal fluid, and, in part, some stored carbohydrate. Tissue analysis indicated the presence of a glycogenlike polysaccharide in the intestinal wall of both active and cold-torpid turtles. It was concluded that, during intestinal transport in Chrysemys picta, some of the glucose absorbed is converted to endogenous carbohydrate, or metabolized, and some is translocated.
Plasma free fatty acid turnover during insulin-induced hypoglycemia
Authors: Armstrong D. T. , Steele R. , Altszuler N. , Dunn A. , Bishop J. S. , de Bodo R. C.
Published: December 2017

Plasma free fatty acid (FFA) concentration falls when an infusion of glucagon-free insulin is initiated in the normal unanesthetized dog in the postabsorptive state. Using C14 palmitate it was shown that the lowered FFA concentration is caused by decreased FFA production. This decreased FFA production accompanies increased glucose uptake by the tissues as demonstrated using C14 glucose. During slow insulin infusion, when plasma glucose concentration remains above 75 mg%, FFA production and concentration remain low. However, during more rapid insulin infusion, when plasma glucose concentration falls below 50 mg%, the initially lowered FFA production rebounds and FFA production and concentration exceed the preinsulin level. Glucose uptake always remains elevated during insulin infusion. Dibenzyline or guanethidine pretreatment blocks the rebound in FFA production. Thus decreased FFA production, due presumably to decreased FFA release by adipose tissue because of insulin-stimulated glucose uptake, can be overpowered by a sympatho-adrenal response to hypoglycemia during a continued infusion of insulin and a resulting continued increased glucose uptake.
Seasonal changes in avian blood pressure related to age, sex, diet, confinement, and breed
Authors: Weiss Harold S. , Fisher Hans , Giminger Paul
Published: December 2017

Systolic arterial blood pressure was measured four times on 219 "outdoor" adult chickens at 6-month intervals which coincided with midwinter and midsummer. Both sexes, seven diets, three types of confinement, and several breeds, strains, and ages were represented. Marked and reproducible seasonal changes in systolic pressure were observed (higher in winter, lower in summer) in essentially every group and subgroup including animals in which huddling was possible and in a selected hypertensive line. Allowance for seasonal changes permitted the following evaluation of the change of pressure with age: 12 mm Hg or 6%/year in the male, 13 mm Hg or 9%/year in the female. The observed seasonal changes were as follows: a) uncorrected for age: 10% decrease from winter to summer, 20% increase from summer to winter, both sexes; b) corrected for age: male, 29 mm Hg, and female, 22 mm Hg change, either season, or a 15% change, both sexes, either season. The average monthly environmental temperature ranged between 1.6 and 21.1 C, and within these limits, the change in systolic pressure/degree Centigrade (age corrected) was 1.6 mm Hg in the male and 1.2 mm Hg in the female.
Autonomic response to cerebellar stimulation in the decorticate cat
Authors: Bruhn John M. , Foley J. O. , Emerson Geraldine M. , Emerson J. D.
Published: December 2017

The cerebral cortex and basal nuclei were removed under intravenous thiopental anesthesia in 63 cats. Beginning 2–3 hr after the final injection of thiopental, the cerebellar cortex was stimulated with bipolar stainless steel electrodes, with isolation of current to the cortex immediately beneath the electrodes. Parameters of the biphasic square wave stimulus were: current density 1.0–3.71 ma/mm2, pulse duration 1.0 msec, frequency 200 cycle/sec, train duration 7–15 sec. Elevation and depression of bladder pressure, constriction and dilatation of the pupil, elevation of blood pressure, and retraction of the nictitating membrane were obtained at P values of <10–7 to <10–10. Responsive areas included lobus simplex, ansiform lobule, paramedian lobule and vermis.
Subcommissural organ and water metabolism
Authors: Upton Peter D. , Dunihue Fred W. , Chambers Wilbert F.
Published: December 2017

The subcommissural organ (SCO) of white rats was destroyed by the use of discrete (1–1.5 mm) lesions. Water intake, urine output, and urine Na and K were measured, and the kidneys examined for changes in the granular cell index. Water intake following complete SCO destruction was reduced for 1 day and then returned to preoperative levels. This change was no different from that observed in rats with no destruction or only partial destruction of the SCO. Urine output fell following SCO destruction and slowly returned toward normal. Rats with partial or no destruction of the SCO showed no change in urine output. All the rats showed a postoperative drop in urine Na and K. There was no change in the granular cell index. Our evidence indicates that the SCO plays no role in water metabolism through control of thirst or through control of aldosterone secretion.
Reduction of increased sensitivity to renin by cross circulation
Authors: Gross F. , Buschor O. , Zeugin H.
Published: December 2017

Cross circulation between pairs of rats was established in order to modify the humoral environment for pressor action of injected renin. Blood exchange with normal rats led to a definite diminution of the increased sensitivity to renin usually seen in the nephrectomized or cortexone-treated animal. The humoral factor reducing renin hypersensitivity is rather stable and exerts its influence not only during, but even after, the duration of cross circulation. It is suggested that normal plasma contains a humoral substance of unknown, possibly renal, origin capable of either antagonizing or inactivating renin. This substance may be renin itself, a factor formed under its influence, or a principle produced by the kidney simultaneously with renin. In animals made hypertensive by an overdose of cortexone and salt, the increased and protracted response to exogenous renin is partly determined by an alteration of the cardiovascular system.
Simultaneous excretion of thiamine and thiamine phosphates by the dog
Authors: Malnic Gerhard , E Silva Maurício Rocha , De Angelis Rebecca C. , Da Silva Alberto Carvalho
Published: December 2017

The fate of intravenously infused thiamine phosphates was studied in the dog. The degree of dephosphorylation by blood, tissue perfusion, and by the kidney was measured. Clearance determinations showed smaller values for these substances than those for creatinine. Concentrated glucose infusions did not change these clearances significantly, but they were increased by inorganic phosphate infusion. Extraction-ratio determinations on unanesthetized dogs showed considerable dephosphorylation by the kidney itself and suggested the possibility of tubular reabsorption. The influence of phosphates was shown to be mainly a protection against dephosphorylation. Perfusion of isolated dog kidneys confirmed these observations and the absence of active tubular excretion of thiamine phosphates, in opposition to active tubular excretion of free thiamine.
Phosphate uptake by isolated rabbit heart
Authors: Omachi Akira , Ginski John M. , Macey Robert I.
Published: December 2017

Isolated rabbit hearts were perfused with Locke Ringer's fluid to which P32 was added. Cellular uptake of P32 was determined by analyzing ventricles from which a rapidly exchangeable extracellular P32 fraction had been removed. In studies on concentration dependence, a plot of phosphate uptake during 1 hr of perfusion against perfusate phosphate concentration revealed that the early phase of uptake follows saturation kinetics. In studies on time course with high external phosphate, i.e., at a level where the uptake mechanism is apparently saturated, relative specific activity (RSA) of total acid-soluble phosphate attained a plateau in 2 hr. RSA is the ratio of specific activities of a tissue fraction to perfusate inorganic phosphate (IP). The plateau was reached at a level corresponding to 10% of the equilibrium value, and it appears that early uptake of phosphate may be confined to a single, rapidly exchanging compartment. This pool appears to contain high-energy and inorganic phosphate since 90% of tissue P32 was found in adenosine polyphosphate, phosphocreatine, and IP fractions. Perfusion with low phosphate led to a decrease in tissue IP with relatively little variation in organic phosphates. This depletion of IP seemed to be accompanied by the emergence of a second compartment as revealed by the RSA data.
Effects of reserpine on circulation of the rat after microwave irradiation
Authors: Cooper Theodore , Pinakatt Teresa , Jellinek Max , Richardson Alfred W.
Published: December 2017

Hyperthermia of 40.5 C was induced in anesthetized white rats by microwave exposure (2,450-Mc continuous wave, .08 w/cm2). Thermal response was accompanied by increased cardiac output, stroke volume, cardiac work, and heart rate. Blood pressure and total peripheral resistance decreased. Administration of reserpine as a single dose of 2.5 mg/kg body wt. 1 day before the experiment depleted the myocardial norepinephrine, but did not eliminate the accelerated heart rate and increase of cardiac output during hyperthermia. Hyperthermia after reserpine did not alter significantly the stroke volume and blood pressure, and the peripheral resistance decreased. These data suggest that the circulatory adaptation to microwave hyperthermia is mediated not only through the sympathetic nervous system, but by other mechanisms such as direct cardiac response to the increased tissue temperature.
Measurement of rapidly and slowly circulating red cell volumes in hemorrhagic shock
Authors: Shoemaker William C.
Published: December 2017

Equilibration of injected Cr51-labeled red cells and Evan's blue dye (T-1824) in dogs occurred usually within 10 min in control conditions. Delayed equilibration of labeled red cells but not T-1824 was observed after hemorrhage and retransfusion of the withdrawn blood. Delayed equilibration of injected labeled red cells may be not only evidence for the presence of a slowly circulating red cell volume, but also may be used as a measurement of this volume. If a two-compartment system is assumed, then the initial volume of dilution of labeled red cells represents a relatively uniform mixing within a volume of rapidly circulating cells. The final volume of dilution of labeled red cells, beyond which no further dilution occurs, is assumed to represent total circulating red cell volume. The difference between these two volumes may represent a slowly circulating red cell volume. It is postulated that the so-called "sequestered" blood volume may, in part, be reflected in this slowly moving red cell volume. If so, the proposed approach under certain conditions may provide an index to its quantitation.
Rheology of blood
Authors: Cerny L. C. , Cook F. B. , Walker C. C.
Published: December 2017

The non-Newtonian flow properties of resuspended red cells were determined in vitro by means of a capillary viscometer. In order to evaluate the rheological effect of the suspending medium, viscosity measurements were made over a wide range of shearing stresses using both plasma and an acid-citrate-dextrose solution as diluents. At low shearing stresses, the plasma exhibited non-Newtonian flow behavior. Using a technique of treating the data to obtain rate-of-shear versus shearing-stress curves without prior assumption of a flow equation showed that whole blood over a wide range of shear stresses and a twofold range of capillary radii did not show any dependence of the viscosity on the capillaries employed. This procedure was also used to examine the data of other workers. In an attempt to determine the shape factor for the red cell, an extrapolation to infinite dilution and zero rate of shear was made. The shape factor can be estimated to be 2.5±1.5 for red cell.
Rhinencephalic spikes and beta waves in the cat under pentobarbital
Authors: Brooks Dana C.
Published: December 2017

Spontaneous electrical activity of the rhinencephalon was studied in the cat under varying depths of pentobarbital anesthesia. Under light anesthesia a distinctive electrical pattern, characterized by an amplitude of over 50 µv and a predominant frequency of 15–50 cycles/sec, has been localized to three structures—the hippocampus, prepyriform cortex, and ventromedial nucleus of the hypothalamus. With increasing depth of anesthesia this pattern is replaced, in each of these structures, by a low-frequency spikelike one. The frequency of both the light and deep anesthesia patterns is highest in the prepyriform cortex, and the deep anesthesia spikes of the hippocampus and ventromedial nucleus are synchronous with prepyriform spikes. Light and deep anesthesia patterns of the prepyriform cortex and hippocampus have their maximum potential gradient in the region of the pyramidal cell layer. Although the spike pattern is not bilaterally synchronous, with very deep levels of anesthesia flat intervals appear between trains of spikes, and these intervals are bilaterally synchronous.
Changes in plasma phospholipids after intravenous phosphatidase A injection in the rabbit
Authors: Klibansky Chaja , Condrea Eleanor , Vries Andre De
Published: December 2017

Intravenous injection of snake venom phosphatidase A into rabbits produced rapid and marked changes in the plasma phospholipids. Five to fifteen minutes after injection there was a marked decrease in plasma lecithin and an increase in plasma lysolecithin. At the same time red blood cell sphering had occurred and lysolecithin was found attached to the red blood cells. Within 2 hr after injection the plasma lysolecithin dropped toward normal, whereas plasma lecithin remained low. The decrease in plasma lysolecithin was paralleled by reversion of the spheric red cell shape to normal bidiscoid. Evidence was obtained for disappearance of plasma phospholipids from the blood stream after phosphatidase injection.
Hexose transport by hamster intestine in vitro
Authors: Landau Bernard R. , Bernstein Leonard , Wilson T. Hastings
Published: December 2017

The ability of everted sacs of hamster intestine to concentrate 18 glycosides and 5-deoxyglucose was determined. It was concluded that most of the glycosides were actively transported, but the nature of the aglycone is an important determinant in the extent of transport. A pyranose configuration is required of a sugar if it is to be transported. Evidence was also obtained which indicates that the carbon-to-hydrogen bonds of carbon 1 and 6 of glucose are transported intact. Therefore, the occurrence during transport of a reaction in which either of these bonds is cleaved appears unlikely.
Bradykinin and cardiovascular system: estimation of half-life
Authors: Saameli Konrad , Eskes T. K. A. B.
Published: December 2017

Synthetic bradykinin in postpartal women produced a decrease in systolic and diastolic blood pressure, reduction of pulse pressure, and increased heart rate and respiration. The threshold dose for single intravenous injections was approximately 0.1 µg/kg, and that for intravenous infusions approximately 0.125 µg/kg/min. For the change in diastolic blood pressure, a linear dose-response curve was found in the semilogarithmic system in the range of 0.125– 1.25 µg/kg/min. In intravenous infusions, the maximal effect appeared, regardless of the dose, after 2–3 min. The time interval between starting the infusion and the onset of effect was distinctly dependent on the dose. These observations indicate exponential elimination or inactivation. Using a formula applicable to exponentially eliminated substances, a threshold level of 0.1 µg/kg and a half-life shorter than 0.5 min were estimated.
Arterial and venous pressure-resistance relationships in perfused leg and intestine
Authors: Hinshaw Lerner B.
Published: December 2017

Pressure-resistance relationships in the kidney have been previously characterized in this laboratory. The purpose of the present investigation was to extend the scope of these previous studies to include tissues other than the kidney. A series of 16 experiments was carried out on the isolated leg and intestine. Organs were perfused at constant pressure by means of a Starling shunt device. Small-vein pressures were determined, and changes in organ weight were continually monitored. Care was taken to achieve an adequate experimental preparation by meticulous ligation of severed vessels and tissues other than the orifice vein. Arterial pressure was increased in a stepwise manner through a wide range. Resistances fell as a function of a rise in perfusion pressure in all instances in leg and intestine preparations. Elevations in small-vein pressure were significantly less than those previously found in the kidney under identical experimental conditions. Results emphasize the similarity of resistance changes in the leg and intestine in contrast to those observed in the kidney.