bluuebunny/crossref_metadata_2025 huggingface dataset:
THROMBOLYTIC THERAPY WITH CA-7 (FIBRINOLYTIC ENZYME FROM ASPERGILLUS ORYZAE) IN THE DOG
Authors: Roschlau Walter H. E. , Tosoni Anthony L.
Published: April 2011

The lysis of occluding arterial thrombi in dogs with intravenous injections of CA-7 (fibrinolytic enzyme from Aspergillus oryzae) is described. The treatments were conducted over a 3-day period and resulted in lysis of 75% of the arterial thrombi. This is compared with the results of an earlier study in which dogs received massive single doses of the enzyme. The therapeutic effectiveness is similar in both series. The 3-day treatment has advantages in reduced toxicity and increased safety.
NATURAL PROTEASE RESISTANCE TO CA-7 (FIBRINOLYTIC ENZYME FROM ASPERGILLUS ORYZAE) IN THE DOG
Authors: Roschlau Walter H. E.
Published: April 2011

Protease resistance, a term applied to the inhibitory effect of all circulating inhibitors of CA-7 (fibrinolytic enzyme from Aspergillus oryzae), was determined in 95 dogs. The frequency distribution of normal protease resistance in this population is shown. From the pretreatment value of protease resistance one can predict in the dog a safe but adequate thrombolytic dose of the enzyme. An evaluation of this dose prediction and its value in the control of thrombolytic therapy with CA-7 are discussed.
DIETARY RESTRICTION AND THE ENDOCRINE TESTIS; SIMULATION OF THE SYSTEMIC EFFECTS OF SEVERE COLD(−5 °C)
Authors: Perrault M. J. , Dugal L. P.
Published: April 2011

Previous work has suggested that the degeneration of the male reproductive system caused by severe cold (−5 °C; 18–32 days) represents the sum of the following factors: (a) systemic, or metabolic alterations in various structures of the entire organism; (b) endocrine, or neurohumoral events, especially androgenic.Observation of changes in weight of the accessory sex organs, prostate and seminal vesicles, as indicators of androgenic function, permits a demonstration of the two separate effects of cold. A restricted diet given to animals at room temperature results in a loss of body weight (percentage of control) almost identical in rate and in level with the loss caused by cold, and simulates the systemic component of the action of cold; the observed loss of weight of the accessories follows the proportionality (nonlinear) between body weight and organ weight. The further loss observed in the accessories of the cold-exposed rat may then be taken to represent the endocrine component, that is, the true androgenic depression; testosterone treatment in the "starved" castrate at room temperature shows the dissociation between the two components.
THE CHRONIC ORAL TOXICITY OF SODIUM CHLORIDE AT THE RANGE OF THE LD50(0.1L)
Authors: Boyd Eldon M. , Abel Miriam M. , Knight Lois M.
Published: April 2011

The chronic toxicity of sodium chloride was studied in young male albino rats given 2.57–6.14 g/kg in water by stomach tube once daily for 100 days or until half the animals had died, whichever occurred first. The LD50(0.1 L) or daily dose which killed 50% of the animals after administration for 100 days, i.e. 1/10 the animal's normal lifespan (0.1 L), was 2.69 ± 0.12 g/kg. It is suggested that the LD50(0.1 L) expressed as a percentage of the acute LD50 would provide a useful index of chronic toxicity; this is termed the C/A LD50(0.1 L) index, C meaning chronic and A acute. The value of this index was 72 for sodium chloride, 62 for benzylpenicillin, and 13 for atropine. Rats which survived doses of the order of the LD50(0.1 L) had no change in food intake but lost some body weight as daily dose increased. They had a dose-dependent polydipsia and polyuria. In the initial month of drug administration the rats developed a slight fever, proteinuria, and alkalinuria, and in the terminal month a slight hypothermia and aciduria, all of which were statistically significant but not dose-dependent. When deaths occurred within the first week or two, they were similar clinically and pathologically to those seen in studies on the acute oral toxicity of sodium chloride. Other deaths followed a period of hypothermic cachexia and were due to bronchopneumonia, associated with hepatitis, nephritis, arteriolitis, and occasionally encephalopathy, and accompanied by degeneration of the thymus, adrenals, and testes. Animals which survived for 100 days had developed a hypertrophied gastrointestinal mucosa but most other organs had lost weight, and there was some arteriolitis, myocarditis, pulmonary edema, and nephritis.
THE PROXIMAL TUBULAR HANDLING OF AMINO ACIDS AND OTHER NINHYDRIN-POSITIVE SUBSTANCES
Authors: Wright L. A. , Nicholson T. F.
Published: April 2011

The proximal tubular handling of a number of endogenous ninhydrin-positive substances in the dog was assessed by comparing the clearances of these substances following the injection of an area-specific nephrotoxin into one kidney, with the contralateral uninjected kidney serving as the control.The upper portion of the proximal tubule was primarily responsible for the reabsorption of most of the amino acids and certain other ninhydrin-positive substances. The lower portion of the proximal tubule seems to possess some secretory function (for cystine, lysine, glutamic acid, glutamine, and an unknown substance) and a fair degree of reabsorptive capacity for most of the amino acids.
THE PLASMA LEVELS, FILTERED LOADS, EXCRETION RATES, AND CLEARANCES OF A NUMBER OF NINHYDRIN-POSITIVE SUBSTANCES BY NORMAL FASTING DOGS
Authors: Wright L. A. , Nicholson T. F.
Published: April 2011

Studies of the plasma levels, filtered loads, and excretion rates of 30 endogenous ninhydrin-positive substances in 10 normal female dogs were carried out to assess more accurately the renal clearances of these compounds under abnormal circumstances.The more prominent amino acids in the plasma, which account for 90% of the total amino acids measured, were glutamine, alanine, lysine, threonine, valine, glycine, serine, asparagine, proline, arginine, isoleucine, leucine, and histidine, in order of decreasing concentration. In the urine, glycine, alanine, glutamine, histidine, 1-methylhistidine, asparagine, threonine, serine, and 3-methylhistidine formed 90% of the total output.The percentage reabsorption by the tubules from the glomerular filtrate of β-alanine was 94.5, 1-methylhistidine 95.4, 3-methylhistidine 96.2, histidine 97.6, and glycine 98.4. Except for hydroxyproline, proline, citrulline, methionine, valine, phenylalanine, isoleucine, leucine, tryptophane, and ornithine, the reabsorption of which was complete or almost complete, the amino acids were reabsorbed by the tubules at a level generally greater than 99%.The renal clearances for most of the amino acids measured in the dog were between 0.5 and 0.2 ml per minute, except for β-alanine, 1-methylhistidine, 3-methylhistidine, histidine, taurine, and glycine, whose clearances ranged in decreasing order from 2.3 to 0.7 ml per minute, and also for those amino acids which were almost completely reabsorbed and whose clearances would therefore be rather low.
DIETARY CONTROL OF SERUM CHOLESTEROL LEVELS IN RATS FED HIGH-FAT, CHOLATE-CONTAINING DIETS
Authors: Wilson R. B. , Martin J. M. , Hartroft W. S.
Published: April 2011

In a series of experiments, rats were fed semisynthetic atherogenic diets containing variable amounts of cholesterol (from 0 to 5%) with 40% of either cocoa butter, dairy butter, corn oil, or linseed oil as the source of fat, and 2% sodium cholate. It was found that serum cholesterol levels increased as the amount of dietary cholesterol increased to the 1% level, but raising the dietary cholesterol above this level did not provoke a proportional change in serum cholesterol during the first 3 months of the experiment.
QUANTITATIVE ASPECTS OF GLUTAMATE UTILIZATION BY RAT ADIPOSE TISSUE AND LIVER IN VITRO: EFFECT OF PERIODICITY OF EATING
Authors: Leveille Gilbert A. , Hanson Richard W.
Published: April 2011

The activity of two pathways supplying substrate for lipogenesis was enhanced in adipose tissue of meal-fed rats. One of these pathways, the forward pathway, involves the entry of α-ketoglutarate into the mitochondria, and metabolism via the Krebs cycle; the second pathway involves the backward flow of α-ketoglutarate to citrate in the cytoplasm, and cleavage of citrate to supply acetyl-CoA. Meal feeding increased fatty acid synthesis via the forward and backward pathways, but the relative amount of glutamate incorporated into lipid via the backward pathway decreased as a result of meal eating. The relative importance of the backward and forward pathways to the incorporation of α-ketoglutarate into fatty acid appeared to be similar for liver and adipose tissue. Lipogenesis from glutamate was significantly greater in adipose tissue incubated in bicarbonate than in phosphate buffer; however, the relative differences between tissues from meal-fed rats and from those fed ad libitum were similar in the two buffers. The possible importance of the backward pathway in the supply of precursors for fatty acid synthesis is discussed.
ELECTRON MICROSCOPY OF THE NEURON MEMBRANE SYSTEMS AND FILAMENTS
Authors: Sandborn Edmund B.
Published: April 2011

In spite of the difficulty in interpreting areas of contact in electron microscopy, the similarities in morphological appearance and the repeated suggestions of continuity of structure between the microtubules and other organelles indicate that the necessary structural requirements for a continuous system of membranes might exist within both neurons and glial cells. A membrane system in continuity with the plasma membrane of the cell would greatly increase the available surface area of any cell.
EFFECT OF PLASMA PROTEINS ON THE FRAGILITY OF ERYTHROCYTES
Authors: Triantaphyllopoulos D. C. , Krikke E. H.
Published: April 2011

Addition of fibrinogen or of the anticoagulant fraction of incubated fibrinogen (AFIF) to fresh blood in vitro decreases both the osmotic and the mechanical fragility of the erythrocytes. This suggests that these proteins contribute to the structural integrity of the red cells. On the other hand, addition of albumin does not affect significantly the fragility. Overnight incubation of the blood–protein mixtures abolishes the protective effect of fibrinogen on both kinds of fragility and that of AFIF on the osmotic type. The increased resistance of the red cells, however, to mechanical trauma in the presence of AFIF remains unaffected by incubation.
EFFECT OF FOOD AND WATER CONSUMPTION, LIVER FUNCTION, AND THYROID FUNCTION ON THE SPONTANEOUS RUNNING ACTIVITY OF WHITE RATS
Authors: Smith Lorraine C. , Dugal L. Paul
Published: April 2011

The spontaneous running activity of male white rats was recorded in standard revolving activity cages under constant conditions of light and temperature. There was no correlation between spontaneous activity and voluntary food and water consumption or body weight gain. Furthermore, spontaneous activity could not be correlated either with liver function or with thyroid function.
HEMODYNAMIC RESPONSE TO EXERCISE AFTER PROPRANOLOL IN NORMAL SUBJECTS
Authors: Cumming Gordon R. , Carr W.
Published: April 2011

Supine exercise after beta-adrenergic blockade with propranolol in six normal subjects caused (a) a mean decrease of 13% in resting heart rate; (b) a mean decrease of 20% in resting cardiac output; (c) a mean reduction of 17% in exercise cardiac output and a mean reduction of 21% in exercise pulse rate; (d) a decrease in the elevation of arterial systolic pressure produced by exercise; (e) an increase in exercise end-diastolic pressures in the left ventricle and in exercise pulmonary artery pressures; (f) more rapid recovery of circulatory function after exercise. There was no consistent change in pulmonary vascular resistance. Even though the normal cardiac response to exercise would seem to be dependent on intact beta-adrenergic receptors, the exercise loads chosen were completed just as easily after the blockade as before.
LEUKOCYTE MOTILITY: I. METHOD OF STUDY, NORMAL VARIATION, EFFECT OF PHYSICAL ALTERATIONS IN ENVIRONMENT, AND EFFECT OF IODOACETATE
Authors: Carruthers Bruce M.
Published: April 2011

A method for the study of random and directed motility of human leukocytes obtained from small amounts of peripheral venous blood is presented in which the cells are studied in vitro under standardized conditions and the results are expressed quantitatively. A small population of subjects in varying states of health was studied. Considerable variation in the amount of leukocyte motility was found. Small variations in the physical environment (direction of motility in relation to gravity, and the presence of currents) had little if any influence on motility. No motility was observed in the presence of iodoacetate at a concentration of 10−4 M. These results suggest that the motility observed is active and metabolism dependent.
DIFFERENCES IN GASTRIC ACID OUTPUT IN RESPONSE TO HISTAMINE BETWEEN MALE AND FEMALE GUINEA PIGS
Authors: Voith K. , Kovacs B. A.
Published: April 2011

Gastric acid secretion in response to graded doses of histamine was determined in 32 male and 50 female guinea pigs. The findings were as follows, (a) The subcutaneous injection of 0.1 mg histamine per kg brought about an identical response in both sexes, (b) Following the administration of 0.2 mg of histamine per kg, both the volume and the acidity were found to be higher in the male than in the female guinea pigs, (c) The subcutaneous injection of 0.4 mg histamine per kg induced a maximal secretory response in both sexes. Under these circumstances, the secretory response (volume, free and total acidity) was found to be significantly higher in the male guinea pigs, (d) Similar results could be obtained after the subcutaneous injection of 0.8 or 1.2 mg histamine per kg. It is concluded that the 'maximum' response to histamine of gastric acid secretion is significantly greater in the male than in the female guinea pig.
RESOLUTION OF BALLISTOGRAPHIC RECORDS INTO CARDIAC AND RESPIRATORY COMPONENTS
Authors: Rautaharju Pentti M. , Josenhans William T.
Published: April 2011

The feasibility of average transient computing (ATC) for elimination of respiratory interference and random variations of the ballistocardiogram (BCG) was investigated. It appears that at least one half of the low-frequency interference in the BCG is not random with respect to the cardiac cycle.If noise is periodic there is an ostensible rapid improvement in the ratio of signal to noise when relatively few transients have been summed, and little or no improvement with increasing number of transients.The behavior of non-random noise in ATC was further studied with the aid of simulation experiments. It was observed that the computed average can be considerably biased if noise is periodic. The error was smallest when the number of transients averaged was a multiple integer of the least common factor of the fundamental frequencies of the signal and periodic noise.Several other potential sources of errors in ATC were discussed. With proper consideration for these limitations, the ATC methods can be used for separation of cardiac and respiratory components of the ballistogram with adequate accuracy for some applications. At the same time, the importance of developing other and more sophisticated ways to eliminate respiratory interference is emphasized. A mechanical device for compensating the effect of respiration was devised.
THE EFFECT OF ADRENALINE ON THE SECRETION AND AMYLASE CONTENT OF PAROTID SALIVA IN MAN
Authors: Newberry P. D. , Burton A. C.
Published: April 2011

The effect of slow intravenous injection of adrenaline on the volume flow and amylase content of parotid saliva in man was studied in three subjects. Saliva was collected by suction cups. Rate of salivary flow and amylase concentration varied widely between individuals and in any one individual from day to day. Adrenaline, at rates of injection of 6 and 3 μg per minute, consistently decreased the volume flow, but increased the concentration of amylase, in parotid saliva. The rate of secretion of amylase (the product of rate of salivary flow and concentration of amylase) remained relatively constant.
ERYTHROCYTE SODIUM TRANSPORT IN HEREDITARY ELLIPTOCYTOSIS
Authors: Peters John C. , Rowland Marlene , Israels Lyonel G. , Zipursky Alvin
Published: April 2011

The active and passive efflux of sodium from erythrocyte membranes was studied in 13 subjects with hereditary elliptocytosis and in 15 normal adult controls. The results indicate that the elliptocytic red ceil membrane is not abnormally permeable to sodium. The active sodium efflux is, however, significantly greater in elliptocytic erythrocyte membranes and suggests that a primary membrane abnormality is responsible for the increased sodium transport.
COMPARATIVE BLOOD PRESSURE AND ELECTROCARDIOGRAPHIC CHANGES INDUCED BY PROSCILLARIDIN AND OUABAIN
Authors: Melville K. I. , Shister H. E. , Klingner B.
Published: April 2011

Femoral arterial blood pressure and electrocardiograms (ECG, lead II) were recorded concurrently in artificially respired cats anesthetized with pentobarbital, and responses to the new squill glycoside, proscillaridin (Talusin), and to ouabain were compared. All drugs were injected intravenously, in groups of five cats for each dose level. Following single injections, it was observed that doses of 150 μg of proscillaridin/kg produced only slight increases in blood pressure and slight bradycardia, but no change in the ECG pattern. In contrast, similar doses of ouabain or doses of 500 μg of proscillaridin/kg produced bradycardia, ventricular arrhythmias, and fibrillation in all experiments. Whereas striking pressor effects were noted with ouabain those due to proscillaridin were slight. With continuous infusions, proscillaridin and ouabain in doses of 5 μg/kg per minute led to similar qualitative and quantitative changes (bradycardia, arrhythmias, and ventricular fibrillation), but these developed more slowly with proscillaridin. Infusions of proscillaridin in doses of 2.5 μg/kg per minute also produced similar but still more delayed changes. Doses of 15 μg/kg per minute of proscillaridin, on the other hand, produced all the effects more rapidly than 5 μg/kg per minute of ouabain, but the pressor response was again less pronounced. It is concluded that (a) proscillaridin exerts characteristic digitalis-like effects; (b) when single intravenous doses are compared, proscillaridin is approximately one-third as toxic to the heart as ouabain; (c) when continuous intravenous infusions are compared, proscillaridin shows variable onset of action depending on dosage and is approximately one-half as toxic as ouabain; and (d) in all experiments proscillaridin exerts less marked pressor effects than ouabain. The drug is being further studied.
LIPOGENESIS IN ADIPOSE TISSUE OF MEAL-FED RATS: A POSSIBLE REGULATORY ROLE OF α-GLYCEROPHOSPHATE FORMATION
Authors: Leveille Gilbert A.
Published: April 2011

The incorporation of acetate-1-14C into fatty acids by isolated epididymal adipose tissue of fed and fasted rats adapted to a single daily 2-hour meal (meal eaters) or fed ad libitum (nibblers) was investigated. Fasting (22 hours) markedly depressed lipogenesis whereas fatty acid synthesis increased linearly with time of refeeding in meal-fed but not in nibbling rats. The activities of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and NADP-malic dehydrogenase in adipose tissue of meal-fed or nibbling rats were not altered as a consequence of a 22-hour fast or of subsequent feeding for 2 hours. The incorporation of acetate-1-l4C into fatty acids by adipose tissue of fasted meal-eating or nibbling animals was markedly enhanced by the addition of unlabeled pyruvate or oxaloacetate to the incubation medium. This stimulatory effect was not observed with adipose tissue front fed meal-eating rats. The addition of unlabeled glucose and insulin to the incubation medium markedly enhanced acetate-1-14C incorporation into fatty acids by isolated adipose tissue and completely overcame any effect of fasting. Adipose tissue converted pyruvate-1-14C, -2-14C, or -3-14C to fatty acids and glyceride-glycerol. The results obtained are consistent with the functioning of a pathway in adipose tissue involving mitochondrial carboxylation of pyruvate to oxaloacetate, and equilibration of the newly formed oxaloacetate with malate and fumarate, followed by cytoplasmic conversion of oxaloacetate to phosphoenol pyruvate. The data are interpreted to support a control mechanism in which fatty acid synthesis is inhibited by tissue fatty acids and fatty acyl-CoA derivatives. The inhibition could in turn be reduced by the availability of α-glycerophosphate, for the esterification of fatty acids. This control mechanism is proposed as the explanation for the refeeding response observed in adipose tissue of meal-fed rats.
PARASYMPATHETIC ACTION ON GASTRIC BIOELECTRIC POTENTIAL IN RATS
Authors: Ridley H. Allan , Vaughan Burton E. , Cummins Joseph T.
Published: April 2011

The gastric bioelectric potential in vitro was consistently lower in stunned rats than in rats anesthetized with ether, or decapitated. This depressed potential was prevented by vagotomy and by atropine either subcutaneously injected or directly instilled. Similarly, transmural potential and short-circuit current were sharply reduced, by one-half, when the solution bathing the mucosal surface was made 10−2 M in acetylcholine (ACh). There was no detectable effect on transmural conductance (dI/dE). Inhibition of potential was proportional to ACh concentration from 10−5 M to 10−2 M. Partial recovery was demonstrated by rinsing and replacing solutions; atropine at 10−4 M irreversibly blocked such inhibition. Tubocurarine at 10−3 M did not change the response, when added prior to ACh, while physostigmine at 10−4 M enhanced the effect of ACh. The ACh analogues acetyl-β-methylcholine, acetylthiocholine, and carbamylcholine, at 10−3 M, reduced potential, as did ACh at 10−3 M. Carbamylcholine, which is not appreciably hydrolyzed by acetylcholinesterase, showed only slightly greater effect than ACh. In these studies, bioelectric potential was altered without any change in the acid secretion rate. This supports other studies demonstrating independence in the isolated rat stomach of electrical and acid secretion parameters.
AFFERENT DISCHARGE PRODUCED BY MUSCLE COOLING IN MICE MAINTAINED AT NORMAL AND LOW ENVIRONMENTAL TEMPERATURES
Authors: Banet M. , Séguin J. J.
Published: April 2011

Muscle receptors in the mouse were shown to discharge in response to cooling of the muscle. Afferent activity was recorded in vitro from the whole nerve of the soleus muscle of 20 male white mice. These animals were maintained at a constant temperature of 22 °C for at least 15 days. In muscles cooled from 37 °C, receptors first showed activity at 32.9 ± 0.89 °C. With further cooling, there was an increase in the number of receptors firing and in the frequency of their discharge. The temperature at which maximum afferent response to cooling (TMA) occurred was 26.6 ± 0.83 °C. Similar experiments were carried out on 61 mice which had been exposed to a constant temperature of 6 °C for periods ranging from 6 hours to 32 days. Sensitivity of the receptors to cooling was significantly decreased following 24 hours' cold exposure (TMA 22.5 ± 1.02 °C) and was lowest after 12 hours' exposure. In animals exposed to cold for 3 days, sensitivity returned to a norma! level (TMA 25.4 ± 1.02 °C), but there was again a decrease in the sensitivity of the receptors to cooling in mice exposed for 5 to 6 days (TMA 22.1 ± 1.13 °C) and in those exposed for 8 to 10 days (TMA 22.4 ± 0.94 °C). Following exposure for 14 to 20 and 30 to 32 days, the sensitivity of the receptors returned to normal levels (TMA 26.3 ± 1.48 °C and 24.6 ± 2.04 °C respectively). At present the mechanisms underlying these changes in sensitivity of muscle receptors to cooling are not known.
WEIGHT GAINS, NITROGEN METABOLISM, AND BODY COMPOSITION OF RATS FED ONE OR FIVE MEALS DAILY
Authors: Friend D. W.
Published: April 2011

Three paired-feeding experiments were conducted to determine the effect on growth, metabolism, and body composition of rats fed one or five meals daily. Each experiment, with six littermate pairs of castrated male rats, lasted 30 days including an 11-day metabolism trial. Rats fed five meals ("multiple-feeders") gained weight at a faster (P < 0.05) rate and yielded heavier (P < 0.05) dry body weights than did those fed one meal daily ("single-feeders"). A higher percentage of fat in the single-feeders resulted in little difference in the weight of carcass fat. A heavier weight of body protein in the multiple-feeders was consistent with their greater (P < 0.001) retention of nitrogen. Water intake and the urinary losses of water and nitrogen were greater (P < 0.001) for the single-feeders.
EFFECTS OF 48/80 OR RESERPINE ON TISSUE ANTIHISTAMINE EXTRACTS
Authors: Stotland M. , Francis L. E. , Melville K. I.
Published: April 2011

An antihistamine principle (AHP) occurs in many animal tissues. The concentration of this principle was studied in extracts of brain, lung, and blood of guinea pigs treated with compound 48/80 or reserpine. After 48/80, the AHP decreased in brain, increased in blood, and did not change in lung. It is postulated that 48/80 might act on the brain or other tissues to release the AHP into the circulation. Reserpine did not influence the AHP levels in these tissues.
THE EFFECTS OF TEMPERATURE ON THE RELEASE OF MATERIAL WITH ACETYLCHOLINE-LIKE ACTIVITY FROM BRAIN SUBCELLULAR PARTICLES
Authors: Hosein E. A. , Levy Robert
Published: April 2011

It was observed that when rat brain subcellular particles were cooled to 0 °C, there was little or no release of materials with acetylcholine-like activity from within the particles into the incubation fluid. When these experiments were conducted at elevated temperatures, there was gradual enhancement of release of these materials, until at about 43 °C, there was a relatively large release. We suggest that extreme hypothermia (below 20 °C) in animals results in the failure of transmission in nerve and brain partly because of the concomitant failure of release of the transmitter substance(s).
THE PHARMACOLOGY OF THE CARDIAC MUSCLE OF THE GREAT VEINS OF THE RAT
Authors: MacLeod Don P. , Hunter E. G.
Published: April 2011

Preparations of rat superior and inferior vena cava and pulmonary vein behave essentially as preparations of atrial and ventricular muscle in response to electrical stimulation and a variety of drugs. In addition, rat inferior vena cava has spontaneous rhythmic activity. Epinephrine, norepinephrine, isoproterenol, and phenylephrine had positive inotropic effects in all three preparations and a positive chronotropic effect in inferior vena cava. All these responses were blocked by propranolol but unaffected by tolazoline. Acetylcholine and carbachol produced a negative inotropic effect in all three preparations and a negative chronotropic effect in inferior vena cava. These responses were blocked by atropine but unaffected by hexamethonium. Angiotensin, histamine, serotonin, and pitocin were without effect on the three preparations studied although slight positive inotropic effects were observed from time to time with angiotensin and serotonin. Transmembrane action potentials of the pulmonary vein and inferior vena cava were compared with those of rat ventricular strips and isolated atria in their response to acetylcholine. The response of preparations of vein was similar to that of atrial muscle in that acetylcholine reduced the duration of the action potentials.
THE EFFECT OF REPEATED HEAT AND COLD EXPOSURE ON SERUM PROTEIN COMPOSITION IN MAN
Authors: Blatt W. F. , Kerkay J.
Published: April 2011

Total protein, serum protein, and lipoprotein electrophoretic distribution and hematocrit values were determined in two groups of men during acclimatization to 6 weeks of cold and 11 days of heat respectively. After 3 weeks of cold exposure total serum protein and albumin content decreased, while the globulin fractions increased; thus, the calculated albumin/globulin ratio was significantly depressed. During the last 2 weeks, these parameters gradually returned to control values. Overall, the protein changes during heat acclimatization were minimal, although the globulins decreased slightly, yielding a small increase in the albumin/globulin ratio. The hematocrit levels were significantly lowered during both environmental exposures, whereas the lipoprotein distribution remained essentially unchanged.
MODEL EXPERIMENTS WITH GADDUM'S PUSH-PULL CANNULAS
Authors: Szerb John C.
Published: April 2011

Push–pull cannulas of various sizes were placed in an agar gel containing 10 μg/ml of quinine sulfate and were perfused at various rates. The quinine content of the outflow was determined fluorometrically. The amount of solute extracted by the cannula depended on the size of the contact area between the perfusion fluid and the gel but not on the rate of perfusion. From data obtained in these model experiments, the diffusible fraction of some of the suspected transmitters in the central nervous system was calculated.
HEMODYNAMIC RESPONSE TO EXERCISE AFTER BETA-ADRENERGIC AND PARASYMPATHETIC BLOCKADE
Authors: Cumming Gordon R. , Carr W.
Published: April 2011

Cardiac responses to supine bicycle exercise were studied in six normal subjects after the intravenous administration of 5 mg of propranolol and again after the additive effect of 0.03 mg/kg of atropine. Mean resting heart rate was decreased 15 beats/min by propranolol and then increased by 38 beats/min after atropine. Mean exercise heart rate was 157 for control exercise, 119 after propranolol and 143 after propranolol + atropine. The resting cardiac index was reduced 21% by propranolol and restored to control values after atropine. The mean control exercise cardiac index was 7.2 l/min per m2; this was reduced to 5.8 after propranolol and increased to 6.2 after atropine. The mean stroke index was not altered by control exercise, increased 3 ml/beat per m2 with exercise after propranolol and increased 6 ml/beat per m2 with exercise after propranolol + atropine. Resting pulmonary artery, aortic and left-ventricular end-diastolic pressures were not altered by propranolol or by propranolol + atropine. The mean control exercise left-ventricular end-diastolic pressure was 9 mm Hg, increased to 19 mm Hg after propranolol and fell to 12 mm Hg after propranolol + atropine. The mean exercise aortic systolic pressure was 10 mm Hg below the value for control exercise after propranolol and 8 mm Hg below control after propranolol + atropine. Atropine lessens the inhibition of the cardiac response to exercise with beta adrenergic inhibition, possibly by increasing the heart rate.
TETRAETHYLAMMONIUM-INDUCED CONTRACTIONS OF FROG'S SKELETAL MUSCLE: I. GENERAL CONSIDERATIONS
Authors: Beaulieu G. , Frank G. B.
Published: April 2011

The mechanism for the production of the 'twitching' response induced by tetraethylammonium (TEA) of the frog's sartorius muscle was investigated. A linear relation was found between the log TEA concentration and the log of the latent period for the onset of the muscle response. The minimum latent period was 5 to 10 sec. Previously it was suggested that TEA caused the release of acetylcholine from intramuscular nerve endings to produce this response (13). The findings that blocking neuromuscular transmission by d-tubocurarine, by reduced extracellular calcium concentrations, or by repetitive indirect stimulation in the presence of hemicholinium also prevented the TEA-induced muscle 'twitching' response support the above suggestion. Exposing the preparation to procaine concentrations too low to block neuromuscular transmission blocked the TEA-induced response, indicating that this response was due to an effect of TEA on the unmyelinated nerve endings.
CONTROL OF THE SALT-SECRETING GLAND OF THE DUCK: I. OSMOTIC REGULATION
Authors: Lanthier André , Sandor Thomas
Published: April 2011

The osmotic regulation of the salt gland secretion was studied in the domestic duck. The response to the intravenous infusion of 5% sodium chloride (850 meq Na per liter) was established in unanesthetized ducks. Sodium bicarbonate (892 meq Na/l) produced a salt gland secretion similar to that after 5% sodium chloride, except that it was accompanied by a moderate diuresis. Mannitol and sucrose had similar effects. On the other hand, urea, ammonium chloride, dextran, and meralluride produced only a small amount of salt-gland secretion of low electrolyte concentration. Antidiuretic doses of Pitressin did not induce secretion of the salt gland.
EFFECT OF INCREASED METABOLISM AND OF HYPERPHAGIA ON DIETARY AMINO ACID IMBALANCE IN THE RAT
Authors: Beaton John R.
Published: April 2011

In male Wistar rats, the effects of cold exposure (6 °C) on dietary amino acid imbalances were investigated. In agreement with the previous observation of Klain et al., exposure to cold throughout the experimental period (28 days) prevented the decreased food intake and body weight gain observed at 24 °C in rats fed a 6% fibrin diet supplemented with 0.4% DL-methionine and 0.6% DL-phenylalanine. It was also observed that subsequent exposure to cold eliminated these effects of an existing- imbalance previously induced at: 24 °C. With a 10% fibrin diet supplemented with 0.6% DL-methionine and 0.9% DL-phenylalanine, no pronounced effect attributable to an amino acid imbalance was observed at 24 °C. It is concluded that exposure to cold prevents the deleterious effects of an amino acid imbalance superimposed on a 6% protein diet, and subsequent exposure to cold eliminates these effects of an existing imbalance, L-Thyroxine, injected daily at a level of 30 μg/100 g body weight, simulated cold exposure in that it caused an increased food intake in rats fed a 6% fibrin – unbalanced diet. In hypothalamic-hyperphagic rats, a deleterious effect of a 6% fibrin – imbalanced diet was apparent initially; after 10 days' feeding, lesioned rats fed a 6% fibrin diet ceased to gain weight whereas those fed the imbalanced diet continued to do so.
Renal–adrenal interrelationships in experimental hypertension
Authors: Ostrovsky D. , Papsin F. R. , Gornall A. G.
Published: April 2011

For several weeks after partial constriction of one renal artery, the fate of this "clipped" kidney seems to exert a determining influence on blood pressure. Rats that remained hypertensive throughout the experiment almost invariably had clipped kidneys averaging 0.16 to 0.22% of body weight. Below 0.1%, this kidney was usually quite atrophic, and its presence was consistent with falling or normal blood pressure. The untouched kidney in such rats was, on the average, heavier in the hypertensive than in the normotensive animals. Since the latter also had less renal tissue on the clipped side, it appears that factors leading to high blood pressure stimulated hypertrophy beyond the level provoked by renoprival factors. In rats on a high salt intake, 5 μg/day of D-aldosterone for 3 months stimulated significant true renal hypertrophy in the absence of a rise in blood pressure. Such hypertrophy was more pronounced in similar rats that had been getting 250 μg DOCA/day for 3 months but were also normotensive. Rats that developed hypertension on this latter regimen had still heavier kidneys. Renal hypertrophy appears to be a prehypertensive phenomenon which persists and can become even more pronounced in hypertension. The highest levels of renal hypertrophy were usually associated with significant adrenal hypertrophy. Endocrine functions may be involved in renal hypertrophy. This concept is discussed in relation to a phospholipid "renin inhibitor" recently isolated from dog and hog kidneys.
Inhibition of purine biosynthesis by analogues of 4(5)-aminoimidazole-5(4)-carboxamide
Authors: Peters D. A. , McGeer P. L.
Published: April 2011

Twenty-three compounds were synthesized as possible antimetabolites of 4(5)-aminoimidazole-5(4)-carboxamide (AIC). The activity of the new compounds was compared with that of 4(5)-diazoimidazole-5(4)-carboxamide, 4(5)-amino-1,2,3-triazole-5(4)-carboxamide, 4(5)-diazo-1,2,3-triazole-5(4)-carboxamide, and 6-mercaptopurine, all of which have been tested by other investigators against nucleic acid synthesis or neoplasms. Activity was judged by retardation of E. coli growth, inhibition of conversion of glycine-14C to hypoxanthine by pigeon liver homogenates, and prolongation of survival of mice following injection of Ehrlich ascites cells. Although none of the new analogues was highly active in the test systems, a number showed comparable or superior activity to the four previously tested inhibitors which were used as standards in this study. 4(5)-Nitroimidazole-5(4)-carboxyhydrazide, 4(5)-acetylamino-1,2,3-triazole 5(4) carboxamide, 4(5)-diazo-1,2,3,-triazole-5(4)-carboxyhydrazide, and 4(5)-diazo-1,2,3-triazole-5(4)-nitrile showed >50% inhibition of glycine-14C conversion at 3 × 10−3 M or less, while 4(5)-nitroimidazole-5(4)-carboxyhydrazide, 4(5)-amino-1,2,3-triazole-5(4)-carboxamidine, 4(5)-amino-1,2,3-triazole-5(4)-nitrile, and 1-benzyl-5-amino-1,2,3-triazole-4-carboxyhydrazide showed >50% inhibition of E. coli growth at 10−3 M. None of the nine compounds of which there was sufficient quantity to be tested against growth of Ehrlich ascites tumor appreciably prolonged the survival of mice following intraperitoneal injection of the cells.
Optical density changes of single muscle fibers in sodium-free solutions
Authors: McLaughlin S. G. A. , Hinke J. A. M.
Published: April 2011

The optical density, O.D., of single striated muscle fibers from the giant barnacle, Balanus nubilus, was measured at 50-mμ intervals between 450 and 850 mμ. At all wavelengths, the O.D. decreased markedly when the normal Ringer bathing solution was replaced by sodium-free sucrose Ringer solution. For example, at 850 mμ the O.D. of the fibers, relative to the initial value in normal Ringer solution, decreased from 1 to 0.21 ± 0.06 in 25 min. The corresponding increase in the transmittance, T, (O.D. = −log T) was from 5% to 55%. This change in O.D. could be reversed by returning the normal Ringer bathing solution to the bath. Large, reversible decreases in O.D. were also observed when potassium and Tris were used as substitutes for sodium. These changes in O.D. are explained by the theory of light scattering if it is assumed that sodium is bound to macromolecules in the myoplasm. This assumption is supported by experiments with cation-sensitive microelectrodes, which indicate that most of the sodium in the muscle fibers is not free in the myoplasm. When the fibers were bathed in sodium-free, lithium-substituted Ringer solution, a small reversible increase in the O.D. was observed, which may indicate that lithium is complexed more strongly than sodium by macromolecules in the myoplasm. This conclusion is compatible with the known affinities of carboxylate ion exchange resins for the alkali metal cations.
The intrarenal distribution of urea-14C as shown by autoradiography
Authors: Baynton Robert D. , Mercer Paul F.
Published: April 2011

By use of an autoradiographic technique sodium and chloride were reported to be distributed in two separate regions in the mammalian kidney, the outer medulla and the papillary tip. Since urea is thought to be the other major component contributing to the overall osmotic pressure of the medulla, a similar pattern to that of sodium and chloride might be expected. Autoradiograms with urea-14C were made from kidneys of rats given a constant infusion of radioactivity and inulin (for the determination of GFR). The urea-14C autoradiograms showed an elevated region of radioactivity in the outer medulla adjacent to a region of lowered deposition in the outer zone of the inner medulla. This latter region was then followed, in the inner medulla, by an increasing deposition of urea-14C towards the papillary tip. This pattern is identical with that previously reported for sodium and chloride, suggesting a similar pattern for the osmotic pressure in the kidney.
Uricolytic enzymes in cod sperm
Authors: Mounib M. S. , Eisan J. S.
Published: April 2011

Cod sperm produced 14C-uric acid when incubated in the presence of 14CO2, suggesting a de novo biosynthesis of purine by fish sperm. Extracts of the acetone powder of cod sperm showed activities of uricase, allantoinase, and allantoicase.
Studies on the relation between plasma antithrombin and heparin-cofactor
Authors: Monkhouse F. C. , Milojevic Susan
Published: April 2011

A method for the preparation of purified plasma antithrombin and heparin-cofactor is described. The method involves adsorption by aluminium hydroxide, separation on a DEAE-cellulose column by means of a graded salt concentration, and vertical curtain electrophoresis. A 100-fold increase in the specific activity of antithrombin and a 30-fold increase in the specific activity of heparin-cofactor have been achieved. In spite of the increased purification, no separation of the two activities was achieved. When a highly purified fraction was subjected to starch-gel electrophoresis for 16–18 h and then eluted from the gel, there was significant loss of heparin-cofactor activity but not of antithrombin activity. The electrophoretic patterns of the recovered proteins were not altered.
Studies in phospholipid metabolism. 2. Incorporation of metabolic precursors of phospholipids in choline deficiency
Authors: Blumenstein J.
Published: April 2011

The incorporation of metabolic precursors of lipids was followed in the livers of rats fed a semisynthetic diet supplemented with, or deficient in, choline. In the early stages of choline deficiency no change was observed in the net incorporation of palmitic acid into liver lipids. Experiments with labelled ethanolamine, choline, and methionine showed that during choline deficiency the direct incorporation of choline into liver lecithins is unchanged, whereas the incorporation of the methyl group of methionine into lecithin, and ethanolamine into cephalins is decreased.
The effect of serum from multiple sclerosis patients on the free fatty acid output of rat brain slices
Authors: Clarke D. W. , Gittens B.
Published: April 2011

Slices of rat cerebral cortex were incubated in a buffered medium containing human sera. If sera from normal persons were used, there was only a very slight net increase in free fatty acid in the medium, but if sera from persons suffering from multiple sclerosis were used, there was a considerable increase in the free fatty acid concentration. This effect is probably not completely specific for multiple sclerosis.
Phosphonolipids. XV. Synthesis of a dihydroceramide aminoethylphosphonate
Authors: Baer Erich , Pal Bimal C.
Published: April 2011

The first chemical synthesis of a dihydroceramide aminoethylphosphonate is described. It is a saturated representative of a new class of recently discovered, naturally occurring complex lipids derived from phosphonic acid. The compound, viz. erythro-N-palmitoyl-DL-dihydrosphingosyl-1-(2-aminoethyl)-phosphonate, was obtained by two procedures: phosphonylation of erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosine with (2-N,N-dibenzylammoethyl)phosphonic acid chloride (hydrochloride) and triethylamine, or with (2-phthalimidoethyl)phosphonic acid monochloride and triethylamine, and freeing the reaction products of both procedures, viz. erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosyl-1-(2-N,N-dibenzylaminoethyl)phosphonate and erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosyl-1-(2-phthalimidoethyl)phosphonate, from their protective benzyl or phthaloyl group by hydrogenolysis or hydrazinolysis, respectively, followed in both cases by removal of the benzoyl group by saponification.The (2-N,N-dibenzylaminoethyl)phosphonic acid was obtained by treating (2-bromoethyl)phosphonic acid with N,N-dibenzylamine and converting the reaction product, viz. the dibenzylammonium salt of (2-N,N-dibenzylaminoethyl)phosphonic acid, into the free acid by steam distillation.
Action potentials in the nerve from the posterior semicircular canal of the cat
Authors: Smith L. M. , Marshall K. C. , Scott John W.
Published: April 2011

A method is described to implant electrodes for recording the electrical activity in the branch of the vestibular nerve from the posterior semicircular canal of the cat. A tungsten electrode eroded to a point is inserted into the nerve through the internal auditory meatus and held in position with dental cement. Satisfactory observations have been obtained for more than 4 weeks from such a preparation. There is a continuous discharge observed in the nerve, when the head is stationary. With the posterior semicircular canal in the plane of rotation the resting discharge increases when the head is given an angular acceleration in the ampulla-leading direction, and decreases if the acceleration is in the ampulla-trailing direction. Blocking the canal does not alter the resting discharge but abolishes the responses to acceleration.
Role of erythropoietin and placental lactogen in the control of erythropoiesis during pregnancy
Authors: Jepson Joanne H. , Lowenstein Louis
Published: April 2011

As pregnancy progressed in the mouse, the time required to clear radioiron from the plasma decreased; incorporation of radioiron into erythrocytes and the 24-h plasma iron turnover rate (PITR) increased. Exposure of pregnant mice to hyperoxia, to suppress endogenous erythropoietin, markedly prolonged the time required for clearance of 50% of the injected radioiron from the plasma [Formula: see text], but this time was significantly faster than that observed in normal mice so exposed. Placental lactogen, which had previously been shown to augment erythropoietin, increased the plasma iron [Formula: see text] clearance time and the incorporation of radioiron into erythrocytes. In pseudopregnant mice, where there is a physiologically balanced ratio of hormones necessary for the maintenance of pregnancy, in the absence of increased erythropoietin the [Formula: see text] and incorporation of radioiron into erythrocytes were normal. The data suggest that during pregnancy the major factor controlling erythropoiesis is erythropoietin. The inhibitory effect of increased concentrations of estrogens during pregnancy is balanced by an increased production of erythropoietin and the presence of such ancillary hormones as placental lactogen. The latter hormone, with erythropoietin, may be responsible for the increased red cell mass during pregnancy.
The utilization of ethanol by the isolated perfused rat liver
Authors: Gordon Ellen R.
Published: April 2011

A series of experiments has shown that the mechanisms by which the metabolism of ethanol occurs are strongly influenced by the partial pressures of the oxygen present in the aerating medium. For the most frequently used gas mixture, 95% O2 + 5% CO2, the ethanol consumption was abnormally large, and proportional to the concentration of ethanol in the perfusate. However, when the system was aerated with 18% O2 + 5% CO2 + 77% N2 the consumption of ethanol was similar to that found in the intact rat. The perfusate concentration of glucose, acetone, and acetic, pyruvic, and lactic acids was measured in all experiments. When ethanol was consumed at these two different rates, increases in the lactic: pyruvic ratio and acetate levels of the perfusate were noted in both types of experiments. However, the utilization of glucose by isolated perfused liver was inhibited, and acetone levels increased markedly, when ethanol was consumed at abnormally rapid rates, although no effect was noted in the perfusate levels of these metabolites when ethanol was consumed at normal rates.