bluuebunny/crossref_metadata_2025 huggingface dataset:
PURIFICATION BY ULTRAFILTRATION OF A FAT-MOBILIZING SUBSTANCE EXTRACTED FROM THE URINE OF FASTING RATS
Authors: Beaton J. R. , Szlavko A. J. , Stevenson J. A. F.
Published: April 2011

A substance (FMS IB) that mobilizes fat in vivo and in vitro can be extracted from the urine of fasting rats and other species. A threefold increase of lipolytic activity in vitro of rat FMS IB was accomplished by ultrafiltration of an aqueous solution through regenerated cellulose tubing (pore size 24 Å) under vacuum (10–15 mm mercury). This procedure removed a large proportion of the protein. Fat-mobilizing activity in vivo also appeared to be increased. Millipore filtration and carboxymethylcellulose treatment were without significant effect on the activity of FMS IB. Sephadex G25 fractionation of the ultrafiltrate indicated three active fractions, the first of which was not associated with protein but coincided with the presence of a small amount of carbohydrate. None of the ultrafiltrate, the residue after ultrafiltration, or a mixture of the two showed evidence of the hypoglycemic property in vivo possessed by original FMS IB. From these observations it is apparent that the fat-mobilizing activity of FMS IB can be dissociated from protein material and from the hypoglycemic property.
CHANGES IN THE RESTING POTENTIAL OF SKELETAL MUSCLE IN RATS WITH COLD ACCLIMATION
Authors: Sherebrin M. H. , Burton A. C.
Published: April 2011

The resting potential of single cells in the flexor thigh muscles of rats was measured in an attempt to find a change in the electrical properties of the cell membrane with cold acclimation, in order to identify and relate metabolic changes occurring with non-shivering thermogenesis. The mean resting potential of cells in cold-acclimated rats was found to be slightly but significantly higher than in the controls. A larger temperature gradient with depth was measured in the cold-acclimated animals than in the controls. If the Q10 of resting potential with temperature is as great as 1.16, the higher potential in the cold-acclimated rats may be accounted for by this temperature difference. The resting potential was also found to vary with depth in both groups of rats. This could not be attributed to temperature gradients, and change from red to white muscle cells with depth is thought to be the main factor for the increase of potential with depth.
SODIUM AND WATER BINDING IN SINGLE STRIATED MUSCLE FIBERS OF THE GIANT BARNACLE
Authors: McLaughlin S. G. A. , Hinke J. A. M.
Published: April 2011

Cation-sensitive glass microelectrodes were inserted into single striated muscle fibers of the giant barnacle, Balanus nubilus, to measure the activity of sodium and potassium in the myoplasm. These measurements, combined with a knowledge of the total cellular water and sodium and potassium content (flame photometry), permitted the minimal percentage of bound sodium and water to be calculated. These values were 84% and 42% respectively. When muscle fibers were soaked in sucrose Ringer solution, about 30% of the total sodium was removed proportionally from the bound and the free fractions. Potassium replaced sodium in the cellular bound fraction. In some experiments the chloride content of muscle fibers was determined. Assuming no binding and a passive distribution of this ion, the results predict 65% binding of the fiber water. This value for water binding was used with the previous data to calculate that 91% of the intracellular sodium and 38% of the intracellular potassium were bound.
CONCENTRATION AND TURNOVER OF CYTOCHROMEcIN SKELETAL MUSCLES OF WARM- AND COLD-ACCLIMATED RATS
Authors: Depocas Florent
Published: April 2011

Cytochrome c concentration in ventrolateral abdominal muscles of cold-acclimated rats was significantly higher than in corresponding muscles of warm-acclimated rats, but concentration of this protein in gastrocnemius muscle was similar in both groups of animals. Average concentration of cytochrome c in all skeletal muscles was higher in cold- than in warm-acclimated rats. Total amount of skeletal muscle cytochrome c per rat, calculated as the product of estimated total muscle mass and average concentration of cytochrome c, was similar in both groups. The fractional rates of turnover of skeletal muscle cytochrome c, labelled by administration of 1-14C-acetate to warm- and cold-acclimated rats, were, respectively −0.050 ± 0.003 and −0.047 ± 0.005 per day, corresponding to half-lives of 13.8 and 14.8 days. The rate of turnover of cytochrome c was 0.5 mg cytochrome c per rat per day at both acclimation temperatures. A value of 14 days for the half-life of sarcosomes is suggested.
VOLUME–PRESSURE RELATIONSHIPS OF THE TURKEY AORTA
Authors: Speckmann Elwood W. , Ringer Robert K.
Published: April 2011

This experiment was an attempt to define the volume–pressure relationships of the untreated turkey aorta and to evaluate the effect on these relationships of treatment with beta-aminopropionitrile (BAPN) and ascorbic acid. Distensibility values (ΔV/ΔP) were calculated for each of three linear segments of the volume–pressure curve for treated and untreated thoracic and abdominal aortas. In general, the distensibility of the thoracic aorta was greater than that of the abdominal aorta. In both aortic segments addition of BAPN to the ration tended to increase, whereas the addition of ascorbic acid tended to decrease distensibility. The volume–pressure curve of the thoracic aorta was sigmoid in nature and demonstrated the greatest distensibility in the normal physiological systolic blood pressure range of the male Broad Breasted Bronze turkey. Both aortic segments exhibited hysteresis and an isobaric volume change upon successive loading. These phenomena decreased in magnitude with successive loadings.
THE EFFECT OF INSULIN ON THE DISTRIBUTION SPACE OF GALACTOSE IN EVISCERATED NORMAL AND DIABETIC RATS AND THEIR SELECTED ORGANS
Authors: Waterman Fern K. , Hetenyi Jr. G.
Published: April 2011

The distribution space of galactose has been determined in normal and diabetic eviscerated–nephrectomized rats and in their hearts, gastrocnemius muscles, and adipose tissues at different levels of plasma glucose, by a method not dependent on the assumption of non-utilization of galactose. Insulin was found to increase the galactose space in the whole carcass, the heart, and in muscle, but not in adipose tissue in both normal and diabetic preparations. This increase after the injection of insulin was found to be smaller in diabetic preparations than in normal ones. NaHCO3partially restored insulin sensitivity in diabetic preparations. There was a negative correlation between the plasma glucose level and the galactose space in the whole carcass and in the heart, and a similar relation in muscle, in the insulin-injected rats. Dinitrophenol and puromycin did not interfere with the effect of insulin on the expansion of the galactose space in the carcass, heart, or muscle.
FURTHER STUDIES ON THE EFFECT OF OCTANOATE ON GLUCOSE METABOLISM IN DOGS
Authors: Sanbar Shafeek S. , Evans John R. , Lin Boniface , Hetenyi Jr. Geza
Published: April 2011

Studies were carried out in anesthetized dogs to elucidate the mechanism of action of octanoate on glucose metabolism.Octanoate infusion in intact healthy dogs significantly decreased plasma glucose concentration, and in four out of seven dogs it raised plasma insulin concentration in peripheral blood. In contrast, intravenous administration of octanoate in four totally pancreatectomized dogs produced only small changes in plasma glucose concentration. These data suggest that the hypoglycemic action of octanoate may be mediated by increased secretion of insulin.The mean k value ([Formula: see text] of plasma glucose concentration) of intravenous glucose tolerance tests was significantly higher (2.38/minute) in healthy dogs that received an infusion of octanoate than in dogs that did not (1.2/minute). Octanoate also produced in healthy dogs greater increases in plasma insulin concentrations of peripheral blood during the tolerance tests. Furthermore, when delivered during a continuous intravenous administration of glucose (about 8 mg/kg per minute), octanoate infusion had no effect on either plasma glucose concentration or the rate of disappearance of glucose-U-14C from plasma to tissues. These findings indicate that octanoate does not impair glucose utilization in healthy dogs but actually improves tolerance of an intravenous glucose load, probably by stimulating greater release of insulin. These findings in vivo are discussed in the light of opposite effects of octanoate in vitro, to be described elsewhere, on glucose metabolism in the isolated heart and fat pad of rats.
EFFECTS OF QUATERNARY BASES AND INORGANIC CATIONS ON ACETYLCHOLINE SYNTHESIS IN NERVOUS TISSUE
Authors: Bhatnagar S. P. , MacIntosh F. C.
Published: April 2011

A number of quaternary bases were tested for their ability to inhibit the synthesis of acetylcholine (ACh) by incubated minced mouse brain. Tetramethyl-, tetraethyl-, tetrapropyl-, and tetrabutyl-ammonium were moderately active as inhibitors, the strongest being the tetraethyl base (TEA), which was 1–2% as active as the hemicholinium HC-3. Weaker activity was exhibited by hexamethonium, d-tubocurarine, and tolazoline; NH4Cl and N-methylnicotinamide were inactive at concentrations up to 10−2 M. Except in high concentrations, none of the bases significantly affected the release of ACh from the tissue into the eserinized medium. The addition of choline to the medium somewhat increased the rate of ACh formation when the bases were absent and strikingly antagonized the inhibitory action of HC-3 and TEA. TEA also resembled HC-3 in that (i) it reduced the ACh content of the preganglionically excited superior cervical ganglion of the cat, though neither stimulation alone nor the drug alone has such an effect; (ii) it killed mice by paralyzing respiration, and this effect was antagonized by choline; (iii) its inhibitory effect on ACh synthesis by intact nervous tissue was not due to direct inhibition of choline acetylase. The finding of Birks and Quastel that extracellular Na+is essential for the synthesis and storage of ACh by perfused sympathetic ganglia was confirmed for incubated brain tissue. Neither the action of HC-3 and TEA in inhibiting ACh synthesis, nor that of Na+in promoting it, has as yet been clarified.
LEUKOCYTE MOTILITY: II. EFFECT OF ABSENCE OF GLUCOSE IN MEDIUM; EFFECT OF PRESENCE OF DEOXYGLUCOSE, DINITROPHENOL, PUROMYCIN, ACTINOMYCIN D, AND TRYPSIN ON THE RESPONSE TO CHEMOTACTIC SUBSTANCE; EFFECT OF SEGREGATION OF CELLS FROM CHEMOTACTIC SUBSTANCE
Authors: Carruthers Bruce M.
Published: April 2011

The random and directed motility of human leukocytes was studied in vitro. Motility was found not to be dependent upon glucose in the medium. 2-Deoxyglucose was found to inhibit all motility completely. Dinitrophenol had a minor suppressive effect on both random and directed motility. Puromycin at 10−3 M and actinomycin D at 10 μg/ml had a disproportionately great inhibitory effect on directed motility, when compared with minor inhibitory effects on random motility. Actinomycin D at 20 μg/ml and trypsin at 0.1 mg/ml were found to inhibit both types of motility almost completely. Segregation of starch from the field of leukocyte motility was found to abolish its chemotactic effect. Restoration of some chemotactic influence was seen if both starch and leukocytes were present in the segregated area.
INITIAL RESPONSE OF HUMAN THYROID, ADRENAL CORTEX, AND ADRENAL MEDULLA TO ACUTE COLD EXPOSURE
Authors: Suzuki Mitsuo , Tonoue Teiichiro , Matsuzaki Shigeru , Yamamoto Kiyoshi
Published: April 2011

Human subjects were exposed nude to a mild cold of 10 to 15 °C for 1 hour in summer. Free catecholamine excretion in the urine increased markedly during cold exposure. The level of plasma cortisol rose slightly but significantly at the end of cold exposure. Plasma PBI did not change significantly. A rise in blood pressure, a decrease in heart rate, a rise in rectal temperature, cold diuresis, and an increase in urinary electrolyte excretion and hemoconcentration were observed as the initial responses to cold exposure. The physiological role played by endocrine glands in these initial responses is discussed. A preliminary experiment of the same type carried out in winter is described, and some differences in the experimental results from those obtained in summer are noted.
FEEDING FREQUENCY AND LIPOGENESIS IN UNDERNUTRITION
Authors: Cohn Clarence , Joseph Dorothy
Published: April 2011

Rats were fed either normal or subnormal amounts of a 60% carbohydrate (sucrose) diet for 12–14 days. Food was available to the control animals at all times and was presented to the undernourished rats either all at once, under which conditions it was eaten in 1–2 hours, or hourly in 24 small aliquots. When lipogenesis by epididymal fat pads of the animals was evaluated, by measuring acetate-1-14C incorporation into lipid in vitro, it was found, compared with the controls, that (a) the rats eating the limited amount of food in a short time period demonstrated increased lipogenesis and (b) those eating 1/24 of the restricted diet every hour exhibited decreased fat formation. It is concluded that when measuring the dynamics of intermediary metabolism, both the amount and the timing of food ingestion require strict control.
EFFECTS OF VAGOTOMY AND RENAL DENERVATION ON RENAL RESPONSE TO BLOOD VOLUME EXPANSION
Authors: Pearce J. W. , Lichardus B.
Published: April 2011

In anesthetized dogs infusion of "artificial blood" caused an initial natriuresis associated with increased glomerular filtration and solute diuresis often supplemented later by an abrupt decrease of free-water reabsorption. A second infusion produced a larger response of similar pattern except for an earlier increase in solute output and often a concurrent decrease in free-water reabsorption. In other dogs with chronic unilateral renal denervation, cervical vagotomy was carried out between successive infusions. The renal responses on the innervated side were not different, before or after vagotomy, from those in intact dogs, implying that vagal afferents did not contribute essentially to the reaction to this type of blood volume expansion. The increase in glomerular filtration rate observed in the denervated kidney after the first infusion could not have been due to a withdrawal of renal sympathetic tone. The patterns of response to infusions, before and after vagotomy, were also not different in innervated and denervated kidneys, but the magnitude of the second diuresis and natriuresis was less on the denervated side. It is suggested that a reduced vascular reactivity of the denervated organ to a humoral effector mechanism could account for its depressed response to a second infusion in relation to that on the innervated side.
THE ROLE OF GROWTH HORMONE AND THYROXINE IN NEPHROGENIC HYPERTENSION AND CARDIAC HYPERTROPHY IN HYPOPHYSECTOMIZED RATS
Authors: Beznak Margaret
Published: April 2011

There was no indication of slowly developing hypertension and cardiac hypertrophy in hypophysectomized rats upon treatment with desoxycorticosterone and salt loading following unilateral nephrectomy. This was the case in both younger (less than 100 g) and older (220–260 g) male rats. However, the weight of the heart and kidney, the blood pressure, and the rate and output of the heart of normal and hypophysectomized rats following unilateral nephrectomy and treatment with desoxycorticosterone and salt loading were not too different when the hypophysectomized rats were given growth hormone and thyroxine. This agrees with the earlier conclusion that thyroxine and growth hormone are required in hypophysectomized rats for the development of hypertension and any significant enlargement of the heart, whether from aortic constriction or from nephrogenic causes.
AN EAR OXIMETER USING D-C. OPERATIONAL AMPLIFIERS
Authors: Paul W. , Woolf C. R.
Published: April 2011

An ear oximeter was constructed with d-c. operational amplifiers and a conventional two-channel earpiece. The amplifiers are required to provide the necessary signal level for continuous computation of the current ratio, corresponding to an estimate of percentage oxygen saturation.Calibration was effected by analysis of 69 arterial blood samples from 23 patients, the values ranging from 60 to 99% oxygen saturation. With the assumption of a linear relationship between recorder currents (or ratio of two currents, one in each color channel), a regression equation for a straight line was calculated, the points having a standard deviation of ± 3.9% from the regression line. Simple inspection, however, revealed a curvature in the arrangement of calibration points. Cornwall, Marshall, and Boyes assert that this is due to an error in the oximeter equation and propose that an equation in the form of a power function be substituted. The experimental data were recalculated to show that the calibration points fit a power curve best when the exponent is equal to two.
BIOASSAY OF ACETYLCHOLINE ON THE SINUS VENOSUS OF THE FROG
Authors: Zapata P. , Eyzaguirre C.
Published: April 2011

Electrocardiographic changes induced by the application of acetylcholine (ACh) to the sinus venosus of the frog in situ are described as simple and accurate for the detection of minute amounts of ACh in small sample volumes. The sensitivity and reactivity of the sinus to ACh are increased by pretreatment with eserine, which also prolongs ACh effects. Cardio-inhibitory responses to ACh are either abolished or reversed by atropine, the latter effect revealing the so-called 'sympathomimetic' effect of ACh on the heart. ACh induces a marked increase in the R–P interval of the electrocardiogram which occurs concomitantly with a decrease in the P–R interval. It is suggested that the R–P interval, as opposed to the P–P interval, provides a better estimate for the bioassay of ACh. Changes in temperature of the sinus venosus (induced by application of solutions) must be controlled for meaningful results.
EXTRACTION, ISOLATION, AND SOME PHARMACOLOGICAL CHARACTERISTICS OF RABBIT RENAL MEDULLARY EXTRACTS
Authors: Kadar D. , Cooper P. D. , Sunahara F. A.
Published: April 2011

The ethanol-soluble long-chain fatty acids present in the rabbit renal medulla were extracted with ethanol, partitioned with diethyl ether, and separated by column and thin-layer chromatography. Six vasoactive substances were isolated; five lowered and one raised the blood pressure of the rat. Their stimulatory effects on isolated rabbit duodenum and guinea pig ileum varied, but differed from those of acetylcholine or histamine. Prostaglandins E and F were detected in the extract by their chemical and pharmacological properties. The other substances could also be related to the biologically active long-chain fatty acids.
The influence of diet on toxicity of the antioxidant 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline
Authors: March B. E. , Biely Jacob , Coates Viona
Published: April 2011

Toxicity for the chick of 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline (EQ) was significantly greater when the diet was low in protein. When fat supplementation of the diet enhanced EQ toxicity the effect appeared to result from an increase in the energy:protein ratio of the diet rather than from the fat itself. The concentration of EQ in the livers of chicks fed 0.25% EQ for 6 weeks was significantly higher when the dietary level of protein was 17% than when the level was 23%.
Factors affecting the retention of 59Fe, 125I, and 51Cr by mice
Authors: Vittorio P. V. , Dziubalo-Blehm S. , Watkins E. A.
Published: April 2011

The effect of fasting and whole-body exposure to radiation on the retention of 59Fe (ferrous citrate), 51Cr (sodium chromate), and 125I (radioiodinated serum albumin (human)), was studied in mice by means of a whole-body counter. The labelled compounds were administered orally, intraperitoneally, and intravenously. The present study indicates that fasting increases the rate of retention of the labelled compounds studied, and the extent of the increase is dependent upon the type of isotopic compound and the route of administration. Whole-body exposure to radiation (500 R) can also affect the retention of these labelled compounds and when affected there is always a decreased retention (increased excretion). The extent of the decrease is influenced by the type of tagged compound and the mode of administration.
Subcellular localization and drug-Induced changes; of rat liver and kidney esterases
Authors: Schwark W. S. , Ecobichon D. J.
Published: April 2011

The subcellular distribution of the esterases of rat liver and kidney was examined by differential centrifugation followed by quantitative titrimetric analysis, starch-gel electrophoresis, and electron microscopy of the subcellular fractions. The esterases were found primarily in the microsomal fraction of the cell. Soluble or cytoplasmic forms of esterases were also found. These conclusions were substantiated by induction studies with DDT and sodium phenobarbitone. Both drugs were capable of inducing liver esterase activity, DDT being more potent. In contrast to the liver, increased kidney esterase activity was not induced by these compounds.
Relation of emotional status to spontaneous hemorrhage in rats
Authors: Biem H. B. , Jaques L. B.
Published: April 2011

Bilateral septal or amygdaloid lesions were produced in rats with an electrode placed by stereotaxis. Equal numbers of the following groups of rats, amygdaloid lesion, septal lesion, amygdaloid sham, septal sham, unoperated, were randomized for examinations. All animals were evaluated preoperatively and postoperatively with emotionality ratings by four independent observers. The animals then received phenylindanedione in their diet for 10 days, at the end of which prothrombin times were determined and autopsy examinations performed. Three observers independently rated the degree of spontaneous hemorrhage, and the location of the brain lesion was confirmed histologically. A positive correlation was found between the degree of observed spontaneous hemorrhage and the emotionality rating in animals receiving anticoagulants (r = 0.85). In animals not receiving anticoagulants, less evidence of spontaneous hemorrhage was observed in animals with amygdaloid lesions than in other groups.
The effect of atropine on the gastroesophageal sphincter
Authors: Lind J. F. , Crispin J. S. , McIver D. K.
Published: April 2011

Pressure characteristics of the stomach, gastroesophageal sphincter, and esophagus were studied in 14 normal subjects to assess the effect of atropine, under resting conditions and during abdominal compression. The investigations were carried out in two parts. In part I manometric recordings from each subject were made on two separate days. On the control day, two separate injections of saline were given and pressures were recorded with and without abdominal compression following each injection. On the test day, the procedure was identical except that atropine (0.015 mg/kg) was substituted for the second injection of saline. In part II of the investigation, pressures from each subject were recorded on one day only. An initial injection of saline was given, followed by pressure recordings. Atropine was then given at a dosage of 0.025 mg/kg and the recordings were repeated. The pressure characteristics of the stomach, sphincter (maximum), and esophagus did not significantly vary at different times on the same day, or subsequent days. The higher dosage of atropine caused a significant reduction in the mean maximum pressure in the sphincter both under resting conditions and during abdominal compression but did not affect pressures in the stomach or esophagus. The drug had a more pronounced effect on the response of the sphincter to abdominal compression than on the resting pressure of the sphincter. From these observations it is concluded that a cholinergic mechanism is partly responsible for the pressure maintained in the gastroesophageal sphincter under resting conditions. This vagal influence is also an important component involved in maintaining the functional integrity of the gastroesophageal sphincter during abdominal compression.
Hormonally maintained high blood pressure following adrenalectomy in rats with adrenal-regeneration hypertension and its possible significance in the etiology of that disorder
Authors: Hall C. E. , Holland O. B. , Hall O.
Published: April 2011

Rats were caused to develop adrenal-regeneration hypertension, and attempts were made to reproduce in them after adrenalectomy the same rate of blood pressure rise as occurred in animals allowed to retain enucleated adrenals, by using aldosterone, corticosterone, or a mixture of the two. Corticosterone at 2.5 mg/day caused a somewhat greater rate of blood pressure increase than occurred in rats retaining regenerating glands, but whereas the latter did not manifest thymus involution, hormone-treated animals did. At 1 mg/day there was a drop in blood pressure following adrenalectomy in rats with adrenal-regeneration hypertension, although not always to normotensive levels, and the characteristic hypotension of adrenalectomized rats was prevented. Rats given 100 μg/day of aldosterone following adrenalectomy maintained a continued rise of blood pressure, the rate not differing significantly from that seen in rats with continuing adrenal-regeneration hypertension. Such rats did not display thymus involution, and the blood pressure response was no greater when 1 mg/day of corticosterone was added to the regimen. It is concluded that if the profile of hypertension and failure to cause thymus involution are valid criteria for establishing the identity of the hormone(s) which cause adrenal-regeneration hypertension, aldosterone appears to qualify. Some reasons for doubting the reliability of these criteria and some of the difficulties encountered in attempting to compare quantitatively the effects of endogenously secreted hormone with exogenously administered hormone are given.
Regulation of sodium reabsorption by the proximal tubules in the dog
Authors: Dirks John H.
Published: April 2011

Micropuncture studies of the proximal tubules suggest that fractional reabsorption is maintained at a constant level by the mechanism of glomerular–tubule balance, best explained at present by changes in intratubular volume which are proportional to and result from changes in the glomerular filtration rate. The precise role of the macula densa renin–angiotensin system in intrarenal regulation of sodium reabsorption has not been critically defined. The important factor in determining the value of fractional reabsorption in the proximal tubule appears to depend upon changes in body fluid volume balance, volume depletion enhancing the rate of reabsorption and volume expansion depressing it. Aldosterone may be an additional regulator of sodium reabsorption in the proximal tubules.
The source and chemical nature of the natriuretic activity of plasma evoked by saluretic "volume reflexes"
Authors: Cort J. H.
Published: April 2011

The evidence that the natriuresis in response to such hemodynamic alterations as infusion of saline or blood and carotid occlusion is related to the appearance of a natriuretic activity in the plasma was reviewed. This activity, which can be assayed by tubular rejection of sodium in the hydrated ethanol-anesthetized rat or chloralosed cat, or by the zero potential current method in frog skin, was most prominent in blood from the internal jugular vein and then the femoral artery; no such activity was found in blood from the renal or femoral veins. It was therefore postulated that this activity is of cerebral origin. Extracts of posterior bovine hypothalamus when treated with proteolytic enzymes first showed an antinatriferic action, which disappeared on longer incubation. This activity is presumably contained in a polypeptide which is present in a larger "hormonogen" molecular form in the posterior hypothalamus; destruction of the posterior hypothalamus results in renal loss of sodium. Some questions remain: are the natriuretic and antinatriferic activities properties of the same substance; and do the activities that have been obtained from the posterior hypothalamus and plasma represent the same substance?
Effect of hypothermia on the secretion of immunoreactive insulin in response to glucose
Authors: Lin B. J. , Hunter J. , Weldon R. , Haist R. E.
Published: April 2011

Insulin levels in the serum of peripheral venous blood samples from normothermic (37 °C) and hypothermic (24.5 ± 0.5 °C) dogs were estimated by immunoassay before and after the intravenous injection of glucose. In contrast to the rapid rise and fall of glucose levels and insulin levels in normothermic dogs following glucose injection, in most of the hypothermic dogs blood sugar levels rose and were sustained above normal levels throughout the test. These changes were accompanied by elevations in blood insulin levels which were sustained or progressively increased. Several hypothermic animals showed a reduced insulin response despite similar changes in blood glucose.
Changes in DNA and RNA in the rat adenohypophysis following bilateral adrenalectomy, sham adrenalectomy, and the chronic injection of cortisol
Authors: Kraicer Jacob , Cheng Su Chiau
Published: April 2011

Changes in adenohypophyseal DNA and RNA content were determined as a function of time following adrenalectomy, sham adrenalectomy, and the chronic injection of cortisol. The stess of operation resulted in a transient increase in adenohypophyseal nucleic acid content, whereas the increase in secretion of ACTH induced by feedback control did not. An attempt is made to correlate the changes in nucleic acid content with the concurrent changes in the intensity of biosynthesis of ACTH.
Dietary protein and chronic intoxication with ethanol
Authors: Lucas Colin C. , Ridout Jessie H. , Lumchick G. L.
Published: April 2011

The nature of the dietary protein was found to affect the degree of inebriation of rats force-fed alcohol. Young adult males, fed diets differing in the protein moiety (6%), were given increasing doses of dilute alcohol by stomach tube, four times per week until, with 5.5 ml 40% v/v, about half of the rats became moderately intoxicated. This amount, which provided about 10% of the total calorie intake, was given until most of the rats in the three more susceptible groups had died. Rats on the other regimens still appeared in good health after 500 days and after more than 200 intubations with alcohol.A slightly improved tolerance for alcohol developed initially but after about 100 intubations tolerance began to decrease, more rapidly in rats fed some diets than in others. Protection decreased in the order (1) egg, (2) a protein mixture derived from seven natural foodstuffs, (3) milk, (4) oats, (5) rye, and (6) a mixture of peanut meal plus soy protein.
The effect of X-irradiation and thermal burn on the intestinal mucosa
Authors: Baker D. G. , Valeriote F. A.
Published: April 2011

A 1-min thermal burn combined with 700 rads whole-body X-irradiation resulted in an increased mortality in the time period associated with death from intestinal injury. However, these conditions failed to produce a significant depression of intestinal mucosa mass or crypt cell population beyond that following X-irradiation alone. The increase in early mortality following the combined injuries must therefore be due to either a functional impairment in the regenerating tissue or in some other critical system.
Studies with chronically isolated rats: Tissue levels and urinary excretion of catecholamines and plasma levels of corticosterone
Authors: Moore Kenneth E.
Published: April 2011

Rats were maintained in individual cages (isolated) or were housed six per cage (community) for 15–17 weeks. There were no significant differences between the body or organ weights or in the tissue content of catecholamines in the two groups. Isolated animals exhibited an increased sensitivity to the toxicity of isoproterenol. The resting plasma levels of corticosterone and the urinary excretion of noradrenaline and adrenaline were the same for both groups. However, when subjected to a mild stress (a new cage and other animals) only isolated rats responded with increased plasma levels of corticosterone and increased urinary excretion of catecholamines.
Central and peripheral anticholinergic potency of some drugs antagonistic to anticholinesterase poisoning
Authors: Madill H. D. , Stewart W. C. , Savoie M. L.
Published: April 2011

The central and peripheral anticholinergic potency of nine drugs together with their therapeutic effectiveness in treating sarin poisoning was measured and compared with atropine. There was a direct relationship between the anticholinergic potencies of these drugs as measured by tests indicative of activity in the central nervous system and their therapeutic effectiveness in treating sarin poisoning. One exception to this was shown by the drug caramiphen, which showed significantly higher therapeutic protection than the drug atropine at equimolar dosages, yet was less active as a peripheral or central anticholinergic drug. High levels of therapeutic protection were directly related to high levels of central anticholinergic potency.
The hypophyseal–adrenocortical response to various different stressing procedures in ACTH-treated rats
Authors: Stark E. , Ács Zs. , Makara G. B. , Mihály K.
Published: April 2011

Twenty-four hours after the last of 14 daily injections of ACTH, the administration of ether, histamine, 1% formalin, or lysine-8-vasopressin produced no rise in the plasma corticosterone level in rats but raised it significantly in saline-treated control animals. As assayed by the plasma corticosterone concentration, ACTH release was found to be inhibited when hypophyseal–adrenocortical responsiveness was not impaired and the peripheral corticosterone level was normal or less than normal. Endotoxin induced nearly the same statistically significant elevation in the ACTH-treated and saline-treated animals. It would appear that it is the high corticosterone level produced by the last ACTH injection that suppresses the corticotrophin-releasing factor (CRF) 24 h later (feedback action) when this level returns to normal or less than normal; and that certain stressors liberate CRF whereas others do not. An explanation for the latter assumption may be found either in the difference in intensity between the stimuli or, more probably, in that the high corticosterone level inhibits the ACTH release mechanism for certain individual stressors, but not for others.
Opposite effect of harmaline on serotonin and on dopamine and its metabolites, homovanillic acid and norepinephrine, in the brain of the cat
Authors: Poirier L. J. , Singh P. , Boucher R.
Published: April 2011

A comparison between the effects of a single injection and of several injections (24 h) of harmaline on the concentrations of serotonin, dopamine, homovanillic acid (HVA), and norepinephrine in different structures of the brains of normal cats gave the following results. Treatment during a 24-h period caused a somewhat higher increase of serotonin in the thalamus and in the striatum than after a single injection but neither treatment affected the concentration of norepinephrine in the hypothalamus. Under the same conditions, a single injection of harmaline produced a slight decrease of HVA but not of dopamine in the striatum whereas the 24-h treatment caused a significant decrease of dopamine and almost complete depletion of HVA in the same structure. A single dose of harmaline (15 mg/kg) injected before L-DOPA (30 mg/kg) prevented the marked increase of dopamine and HVA that normally occurs in the striatum after the injection of L-DOPA alone. Harmaline injected before 5-HTP did not prevent the marked increase of serotonin in the thalamus and in the striatum. Harmaline appears to have a trapping effect on dopamine in the striatum by inhibiting its conversion to homovanillic acid and by simultaneously preventing its formation from L-DOPA This peculiar effect of harmaline is considered in relation to its effect on extrapyramidal syndromes which are known to be associated with a metabolic imbalance of the monoamines in extrapyramidal structures.
Fecal excretion of thyroxine in warm- and cold-acclimated rats
Authors: Magwood S. G. A. , Heroux O.
Published: April 2011

The daily excretion rate of fecal thyroxine was determined in warm- or cold-acclimated rats. Fecal thyroxine and dietary thyroxine were measured directly by a competitive protein binding analysis technique. An analysis of the Master laboratory chow diet confirmed that one-third of the iodine content was in the form of thyroxine. When fed this diet, cold-acclimated rats ingested 70% more thyroxine and excreted 75% more thyroxine than warm-acclimated rats. On the other hand, rats fed a thyroxine-free diet supplemented with iodine in the drinking water, while showing no significant increase in fecal excretion of thyroxine upon cold acclimation, developed a similar degree of cold resistance as those fed the Master laboratory chow containing 0.58 μg/g of thyroxine. Rats on a thyroxine-free diet showed a significantly lower fecal thyroxine excretion rate at both temperatures than did those on the Master laboratory chow. The results indicate that the greater fecal clearance of thyroxine usually found in cold-acclimated rats is not an essential feature of cold acclimation and depends either on the increased fecal bulk or the increased ingestion of dietary thyroxine.
The Elastic Properties of the Human Great Saphenous Vein in Relation to Primary Varicose Veins
Authors: Booking J. Kenneth , Roach Margot R.
Published: April 2011

Simultaneous measurements of pressure and volume were made on nine great saphenous veins obtained at autopsies and nine great saphenous veins that were stripped during surgery from patients with primary varicose veins. Similar measurements were also made on six great saphenous veins obtained at autopsy before and after they were held at 100 cm H2O for 4 h. Circumferential tensions were calculated from Laplace's law (tension = pressure × radius).The great saphenous veins from patients with primary varicose veins had significantly greater radii and were more distensible than the normal great saphenous veins. After being held at 100 cm H2O for 4 h, the normal great saphenous veins became less distensible and their radii at distending pressures increased.Due to the great difference in radii, the circumferential tension on a great saphenous vein from a patient with primary varicose veins is much greater than that on a normal great saphenous vein at the same distending pressure. However, the physical stresses exerted on the great saphenous veins during the stripping operations may influence our results in some unknown way.
Cardiac Output Distribution in Rats Measured by Injection of Radioactive Microspheres via Cardiac Puncture
Authors: Rakušan Karel , Blahitka John
Published: April 2011

A modification of the microsphere method for the measurement of the cardiac output distribution in small experimental animals is described. The method is suitable for use in both anesthetized and unanesthetized animals. Radioactive microspheres are injected into the left ventricle by cardiac puncture through the closed thorax, which eliminates the need for the cannulation of the left ventricle. The results obtained by this modified method in rats agree with those based on the injection of microspheres through the left ventricular cannula. The described method is suitable for the detection of changes in cardiac output distribution as demonstrated by comparing the results in anesthetized and unanesthetized animals. The cardiac output distribution measured by the microsphere method differs significantly from that based on the rubidium method. The main feature is the fact that the rubidium method tends to overestimate the fractional blood flow to organs with two systems of capillary bed.
The Effect of a Single Large Dose of Cyclophosphamide on Erythropoiesis and Iron Metabolism in Mice
Authors: Aggio Mario Carlos , Fernández Luis María , Bruzzo María Teresa , Alperin Mario
Published: April 2011

The effects of a single large dose (350 mg/kg) of cyclophosphamide on erythropoiesis and iron metabolism was studied in BALB/ep mice. These effects include erythropoietic depression lasting 7–10 days followed by a phase of recovery. The depressant action of the drug on erythrocyte production is accompanied by other metabolic effects on iron and hemoglobin metabolism.The erythroid aplasia develops faster and is more profound in spleen than in bone marrow. Radioactive iron injected 8 h after cyclophosphamide is cleared by bone marrow and liver with values above normal and released very slowly. These effects were not observed in the spleen. Differences in iron handling among the diverse sectors of iron stores suggest interference by this drug on the mechanism of hemoglobin breakdown and iron metabolism and an inhomogeneity of the reticuloendothelial system.
Ontogenesis of Sympathetic Fibers after Neonatal 6-Hydroxydopamine Treatment in the Rat
Authors: Singh B. , Champlain J. De
Published: April 2011

The ontogenesis of peripheral sympathetic neurones was studied in the rat following subcutaneous injections of 6-hydroxydopamine (6-OH-DA), 100 mg/kg, 1, 3, and 5 days after birth. This treatment caused severe and long-lasting depletions of noradrenaline (NA) in various peripheral organs. Thirteen months after treatment, the endogenous NA content of the submaxillary gland and the spleen was 85% lower than in age-matched control animals, 70% lower in the duodenum, 60% lower in the heart, and 25% lower in the large intestine, while the catecholamine content in the adrenal glands was totally unaffected. The adrenergic cell population of the sympathetic ganglia was greatly diminished following treatment, but a few morphologically normal cells survived. These were probably responsible for the partial growth of fibers in all organs studied.Neonatal 6-OH-DA treatment also caused marked alterations in the ontogenesis of central noradrenergic neurones. The results suggest that 6-OH-DA crosses the blood–brain barrier when administered during the first week after birth, thereby causing an important impairment of terminal fiber growth in the anterior portion of the brain and spinal cord. The cell bodies localized in the brain stem are unaffected by this treatment.Although the neonatal treatment with 6-OH-DA greatly affected the ontogenesis of both peripheral and central adrenergic fibers, it did not cause a complete and permanent sympathectomy.
Renal Cortical Slice Uptake and Runout of N-methylnicotinamide and p- Aminohippurate after Potassium Dichromate Treatment
Authors: Hirsch G. H. , Pakuts A. P.
Published: April 2011

Administration of 40 mg/kg potassium dichromate to adult male rats produced a significant enhancement of N-methylnicotinamide (NMN) uptake by renal cortical slices when measured 24 h after a single subcutaneous injection. Incubation under nitrogen or in the presence of dinitrophenol reduced NMN accumulation by kidney slices from control and treated rats to the same level. The rate of NMN runout was slower in renal cortical slices from rats treated with 40 mg/kg potassium dichromate, while p-aminohippurate (PAH) runout was significantly greater than control.
Actions of Atropine, Hemicholinium-3, and Physostigmine on Chlorpromazine-Induced Changes in Rat Brain Monoamines
Authors: Bhatnagar Satya P.
Published: April 2011

The influence of atropine, hemicholinium-3 (HC-3), and physostigmine on the accumulation of monoamines after monoamine oxidase inhibition with pargyline, and on their disappearance after synthesis inhibition with α-methyl-p-tyrosine (α-MT), was investigated in whole brain of normal and chlorpromazine (CPZ)-treated rats. The results disclosed that the accumulation of dopamine (DA) and serotonin (5-HT) is significantly inhibited by atropine and HC-3, as is the loss of DA. None of these drugs affected the noradrenaline (NA) accumulation except for HC-3, which produced a small but statistically significant potentiation. Both atropine and HC-3 increased while physostigmine inhibited the disappearance of NA. These drugs, however, had no effect on the normal cerebral concentrations of monoamines. CPZ substantially increased the accumulation of DA and 5-HT and the loss of DA and NA without affecting their normal concentrations. HC-3, and to some extent atropine, inhibited the action of CPZ on the accumulation of DA and 5-HT. These drugs also inhibited the CPZ-induced accentuation of DA loss but enhanced that of NA. Physostigmine produced the opposite effects. In both normal and CPZ-treated animals, choline, which by itself was ineffective, partly reversed the actions of HC-3 but not that of atropine. These results support the hypothesis of cholinergic–aminergic interaction at the cerebral level and demonstrate the usefulness of HC-3 as a tool in such investigations.
The Additive Effects of Tranquilizers and Dopamine on Smooth Muscle
Authors: Muller P. , Seeman P. , Spero L.
Published: April 2011

(1) The carbachol-contracted ileum was inhibited 50% by 3.5 × 10−6 M dopamine, 7 × 10−8 M chlorpromazine, and 4 × 10−7 M haloperidol.(2) The electrically contracted ileum was inhibited 50% by 2.5 × 10−6 M dopamine, 10−7 M chlorpromazine, and 3.5 × 10−6 M haloperidol.(3) The two neuroleptics did not increase the dopamine mean inhibitory dose (ID50), nor did dopamine alter the ID50 for the neuroleptics. The evidence does not support the receptor–blockade theory of neuroleptic action, since the neuroleptic and dopamine actions in the ileum were additive. The evidence provides some support for the excitability–blockade hypothesis of neuroleptic action.
Effect of Acetaldehyde on the Isolated, Non-working Guinea-Pig Heart: Independence of the Coronary Flow Increase from Changes in Heart Rate and Oxygen Consumption
Authors: Nguyen Minh-Hau , Gailis L.
Published: April 2011

Guinea-pig hearts were perfused at constant pressure with Krehs–Henseleit bicarbonate buffer equilibrated with 95% O2 – 5% CO2. Acetaldehyde at 1 and 5 mM increased coronary flow, oxygen consumption, and heart rate. At 0.2 mM, it increased coronary flow and oxygen consumption only. In the rapidly paced heart, 1 mM acetaldehyde increased coronary flow, but not heart rate or oxygen consumption. Acetaldehyde increased coronary flow and oxygen consumption of the potassium-arrested heart. Acetaldehyde increased all parameters of the hypoxic heart (25% O2 gas phase), but the anoxic heart was not affected (coronary flow was already maximal).Reserpine (in vivo) and catecholamine β blockers (dichloroisoproterenol and propranolol) (in vitro) blocked the heart rate increases and moderated the rise in oxygen consumption. Dichloroisoproterenol plus phentolamine blocked the increases of both heart rate and oxygen consumption. None of the compounds affected the increase of coronary flow produced by acetaldehyde. Epinephrine, norepinephrine, and tyramine increased the heart rate and oxygen consumption, but not the coronary flow. Theophylline increased all three parameters. Neither tranylcypromine nor atropine modified the acetaldehyde effect. We conclude that the increase in heart rate is mediated by catecholamine β receptors. The increase in coronary flow is independent of the increase in heart rate or oxygen consumption and is not mediated by catecholamines.
The Capillary Endothelium in the Rete Mirabile of the Swimbladder of the Eel (Anguilla anguilla): Functional and Ultrastructural Aspects
Authors: Bendayan M. , Sandborn E. B. , Rasio E.
Published: April 2011

The rete mirabile of the swimbladder of the eel is a network of straight capillaries, one against the other, in which an arterial capillary alternates with a venous capillary. The function of these capillaries is to allow the swimbladder to concentrate oxygen by a hairpin countercurrent multiplication mechanism.Electron microscopy shows a very large number of channels in the endothelial cells and most of the channels have alternating dilatations and constrictions as though fixed in a condition of peristalsis. The findings suggest that there is a continuity between the organelles and indicate that the hairpin countercurrent multiplication mechanism may be dependent upon a continuous active return system composed of the membrane-bound channels.