bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microvascular Flow Velocity in Cat Omental Adipose Tissue as Affected by Sympathetic Nerve Stimulation
Authors: Rosell Sune , Intaglietta Marcos , Tuma Ronald F. , Arfors Karl‐E. 
Published: December 2008

AbstractThe effect of sympathetic nerve stimulation on the microvascular red blood cell flow velocity was measured in cat omental adipose tissue. Electrical impulses of 10 V, 0.5–6 Hz were utilized to stimulate the appropriate branch of the splenic nerve. Microvascular velocities were measured in the transilluminated omental bursa in arterioles, capillaries and venules, on‐line, by means of a dual window television system. The responses noted were: 1) decrease in flow (75% of vessels); 2) no response (7%); and 3) increase (18%). The magnitude of the responses were in proportion to the stimulatory frequency. The disparity of responses may be related to previous morphologic observations on the non‐uniformity of innervation of canine subcutaneous adipose tissue. It is proposed that the various vascular reactions reflect the presence of compartments, in the same tissue, endowed with different sympathetic controls. Indexable words. Sympathetic activity, adipose tissue, capillary flow, lipolysis, television microscopy.
Potentiation and Inhibition of Noradrenaline Induced Contractions of the Rat Portal Vein in Anion Substituted Solutions
Authors: Wahlström Bo A. , Svennerholm Bo 
Published: December 2008

AbstractThe effect of anion substitution on spontaneous mechanical activity and noradrenaline induced excitation of the rat portal vein was studied. When chloride was substituted by nitrate and bromide the spontaneous activity was increased, while pyruvate, isethionate and benzenesulphonate decreased it. When noradrenaline was given initially the response was potentiated in all solutions. The order of potency was benzenesulphonate > isethionate > pyruvate ≥ Br−≥ NO−3. When dose‐response curves for noradrenaline were made in normal solution and in anion‐substituted solutions it was found that NO−3 and Br− increased the sensitivity of the muscle cells to noradrenaline, while in isethionate and benzenesulphonate solutins the responsivenss was reduced. Stepwise substitution of CI− by NO−3 or Br− showed that the effect of noradrenaline was inversely related to [C1−]0. When the membrane was depolarized by solutions with excess [K.+]0 the response to noradrenaline gradually fell, although about 15 % was still present in high K+solution. It is concluded from the experiments that the distribution and permeability of anions greatly influence the excitatory effect of noradrenaline on the rat portal vein.
Transfer of TRH through the Placenta and Metabolism in the Fetus of the Guinea‐Pig
Authors: Lybeck Harry , Virkkunen Pekka 
Published: December 2008

AbstractThe permeability of the placenta to thyrotropin‐releasing hormone (TRH) and the fetal metabolism of this hormone were studied by giving iodine‐labelled synthetic TRH to pregnant guinea‐pigs during the first trimester. The radioactivities of various tissue fluids (serum, urine, amniotic fluid and maternal bile) and tissue samples (kidney, liver, small intestine, muscle and cortex) of both mother and fetus were counted. The biological activity of the transferred synthetic TRH was measured in fetal serum by bioassay. Direct measurements of placental permeability to TRH is presented. In the mother the metabolism seems to be the same as in mice and rats (Redding and Schally 1971, Virkkunen, Leppaluoto and Lybeck 1972). In the fetus the main elimination route of TRH is through the liver to bile, in contrast to the rapid urinary excretion in the mother. The half‐life of TRH in the fetal serum is about ten times as long as in the mother, reflecting a different elimination mechanism. Fetal tissue concentrations of TRH are comparable to those of the mother, and so may trigger the endocrine development of the fetal thyroid‐adenohypophyseal system.
The Variation with Age of Tissue Zinc Concentrations in Albino Rats Determined by Atomic Absorption Spectrophotometry
Authors: Bergman Bo , Sjoström Rolf , Wing Kenneth R. 
Published: December 2008

AbstractAn atomic absorption spectrophotometry method for the determination of zinc concentrations in biological tissue samples has been refined. All samples are ashed for 16 hours at 550° C and each determination on a mineralized tissue sample is corrected for the absorption due to the high calcium concentration by subtracting a further absorption measurement at a second wavelength. The method is without detectable systematic error, except for 15–20 % losses of zinc from serum samples, and the random error is less than 2 %. The method was compared with neutron activation analysis on duplicate tissue ash samples and the agreement of the determinations was very good. The method was used to determine the zinc concentrations in samples of serum, heart and selected viscera, teeth and bones from albino rats at various ages during growth. Of these, only the zinc concentration in heart is stable. In pancreas and incisor crowns the concentrations are correlated to the serum concentration and those in the bone samples are correlated to the total mineral (ash) content in each. The ash weight zinc concentrations in bones, the fresh weight concentrations normalized to the total mineral content, are correlated to the serum zinc concentrations.
Relationship between Perivesical and Intravesical Urinary Bladder Pressures and Intragastric Pressure
Authors: Bjerle Per 
Published: December 2008

AbstractThe intragastric pressure and the perivesical and intravesical urinary bladder pressures were measured in the supine and sitting positions immediately after micturition in 9 healthy men. The intragastric pressure was measured with an air‐filled rubber balloon, the perivesical pressure with an open liquid‐filled catheter inserted above the pubic bone into the space of Rezius and the intravesical pressure of the almost empty bladder with a catheter inserted supra‐pubically. There was no difference between the intragastric pressure level and the peri‐ and intravesical pressure levels in the supine position, but in the sitting position the peri‐ and intravesical pressure levels were higher than the intragastric pressure levels due to the pressure effect of the viscera. There was no difference between perivesical and intravesical pressure levels in either the supine or sitting position. Rapid pressure change produced by straining or coughing produced a smaller pressure increase peri‐ and intravesically than intragastrically due to delayed pressure equilibration because of inhomogeneity of the abdominal contents.
The Hypothalamus and Vagally Mediated Gastric Relaxation
Authors: Lisander Bjorn 
Published: December 2008

AbstractExperiments, with recording of gastric volume, were performed in chloralosed cats. Topical hypothalamic stimulations produced vagally mediated increases in volume by two mechanisms. One type of response, due to central inhibition of vagal excitatory tone was induced from the defence area and eliminated by atropine or vagotomy. The other type of response, far less commonly encountered, remained after atropine and spinal cord section, but was abolished by vagotomy. The latter type was not induced from any well defined hypothalamic region, and had a high stimulation threshold. While sham feeding in conscious cats with esophagostomy and gastrostomy induced prompt, marked and longlasting gastric volume increases in connection with swallowing, such responses were not evoked as “anticipatory” reaction to food intake. The relaxations could be prevented by vagotomy but not by guanethidine nor atropine. It is concluded that the vagally mediated relaxation in connection with sham feeding occurs mainly from activation of mechanoreceptors and that the hypothalamic control over the vagal relaxatory fibres is probably minor.
Disappearance of 3H‐Corticosterone from the Serum of Obese‐Hyperglycemic Mice (Gene Symbol ob)
Authors: Naeser Peter 
Published: December 2008

AbstractThe disappearance of 3H‐corticosterone from the serum was measured in obese‐hyperglycemic mice and their lean litter mates of various ages. At 1 month of age the serum half‐life of the injected tracer was the same in the obese and lean animals. In the 2, 5 and 12 months old mice the tracer hormone disippeared faster in the obese mice than in their lean controls. The present results confirm that the previously observed enlargement of the adrenal cortex and the increased secretion of corticosteroids by adrenal glands in vitro in fact indicate a considerably hyperadrenocorticism in the obese mouse. Furthermore, the difference in disappearance rate of corticosteroids in vivo between obese and lean mice approximately parallels the age variation of the other metabolic abnormalities of the syndrome suggesting that the hyperadrenocorticism is part of the multiendocrine disturbance which manifests itself as the obese‐hyperglycemic syndrome.
Prostaglandin Release and Mechanical Performance in the Isolated Rabbit Heart during Induced Changes in the Internal Environment
Authors: Wennmalm Ake 
Published: December 2008

AbstractThe isolated rabbit heart was perfused according to the Langendorff technique. Prostaglandins in the effluent from the organ were identified by use of thin layer chromatography and assayed on the rat stomach strip, The effect of alterations of the physical and chemical conditions of the perfusion medium on the overflow of prostaglandins from the heart was studied. In addition, the capacity of noradrenaline and acetylcholine to release prostaglandins was tested. Acidosis, hyperthermia. hypothermia, hypotension, hyperosmolarity and increased [K+] or [Ca++] levels, while all inducing marked changes in the mechanical activity of the heart, did not induce prostaglandin release. Hypoxia, on the other hand, stimulated the liberation of prostaglandins. Noradrenaline was a potent agent for stimulation of prostaglandin release, in the absence of alpha‐ and betaadrenergic receptor blockade. Acetylcholine was also found to liberate prostaglandins, by activation of muscarinic receptors. The prostaglandin releasing capacity of acetylcholine was about 3 times weaker than that of noradrenaline. It is concluded that the release of prostaglandins from the rabbit heart is not dependent on the mechanical activity of the organ. Furthermore, it is suggested that prostaglandins released by hypoxia may play an important role in the development of reactive hyperemia. Finally it is stated that the release of prostaglandins from the heart caused by acetylcholine may constitute the negative link in an endogenous prostaglandin mediated feed‐back inhibition of the release of acetylcholine from parasympathetic nerve endings.
Role of the Symphato‐Adrenal System in Hemorrhagic Hyperglycemia
Authors: Järhult Johannes 
Published: December 2008

AbstractArterial and venous plasma glucose concentration was determined at intervals in cats subjected to hemorrhagic hypotension at 50 mm Hg. The rapid rise of arterial plasma glucose after hemorrhage could be. attributed to an increased release of glucose from the liver. This hyperglycemia could not be eliminated by bilateral adrenalectomy or by sectioning of the hepatic sympathetic nerves, although the response was somewhat depressed by the latter procedure. On the other hand the hyperglycemia was virtually abolished after adrenalectomy when combined with bilateral sectioning of the major and minor splanchnic nerves. The level of plasma glucagon during hemorrhage increased in cats with an intact sympatho‐adrenal system, but was unchanged in animals with combined splanchnic sympathectomy and adrenalectomy. It is concluded that, during hemorrhage, the sympatho‐adrenal system influences the glucose output from the liver by three different reflex mechanisms: (a) release of catecholamines from the adrenal glands; (b) direct sympathetic nerve influence on the liver; and (c) release of glucagon from the pancreas.
Some Metabolic Consequences of the Anaphylactic Reaction in the Rabbit
Authors: Fredholm Bertil B. , Strandberg Kjell 
Published: December 2008

AbstractThe administration of egg albumin to rabbits sensitized to this antigen caused marked increases in the arterial concentration of lactate, glucose and glycerol, but no change in the arterial FFA level. Antigen administration had no effect in non‐sensitized rabbits. Phentolamine (3 mg/kg) or propranolol (1 mg/kg) did not significantly alter the responses to egg albumin in sensitized rabbits. Noradrenaline or sympathetic nerve stimulation decreased blood flow but caused no significant change in lipolysis in rabbit epigastric adipose tissuein situ. It is therefore questionable if catecholamines are the major cause of the observed metabolic consequences of the anaphylactic reaction in the rabbit. These metabolic events,i.e. increased lactate levels, lipolysis, and reesterification of fatty acids, are similar to those reported during hemorrhagic or endotoxin shock in dogs, in spite of species‐differences and the difference in the genesis of the shock.
Effect of Substance P on Various Vascular Beds in the Dog
Authors: Hallberg Dag , Pernow Bengt 
Published: December 2008

AbstractUsing the electromagnetic flowmeter technique, the blood flow in the aorta, carotid, hepatic, superior mesenteric, renal and femoral arteries and portal vein was recorded during continuous i.v. infusion of synthetic Substance P (SP) in 8 dogs. Systemic and portal blood pressures were recorded. A significant decrease in mean arterial blood pressure was recorded at infusion of SP in the femoral vein at a rate of 2.5 ng × min‐1× kg b.w.‐1 or higher. Portal venous blood pressure increased. A rapid increase in the carotid, hepatic, mesenteric and portal blood flow was obtained at infusion rates of 1.2 ng × min‐1× kg b.w.‐1 or higher. The femoral artery responded with a late, transient increase in flow, with a return to the base level while the infusion was still in progress. The renal artery blood flow decreased slightly at low infusion rates and increased at higher. At SP infusions in the portal vein the infusion rate had to be increased to 20 ng × min‐1× kg b.w.‐1 or higher before any general vascular reactions were recorded, indicating that the liver has a high capacity for inactivating SP.
Mitochondrial Respiration in the Ventricular Myocardium and in the White and Deep Red Myotomal Muscles of Juvenile Tuna Fish (Thunnus thynnus L.)
Authors: Modigh M. , Tota B. 
Published: December 2008

AbstractThe respiratory activity of mitochondria isolated from the outer and inner layers of the ventricular myocardium and from the white and deep red myotornal muscles of juvenile Thunnus thynnus has been compared. The highest values for the succinate oxidase and succinate cytochrome c reductase activities have been found in the mitochondria of the outer myocardial layer, followed by mitochondria of the deep red muscle, the inner myocardial layer and the white muscle in that order. Differences in mitochondrial NADH‐cytochrome c reductase activity run parallel, in a lower order of magnitude, to the differences in the oxidation of succinate. This finding is discussed in relation to the different metabolic attitudes of the muscle tissues towards anaerobic glycolysis. The outer myocardial layer of the juvenile tuna ventricle has been shown to have a higher metabolic activity than the inner layer, in contrast to the situation in adult ventricular myocardium.
Detection of Natural Complex Sounds by Cells in the Primary Auditory Cortex of the Cat
Authors: Sovijärvi Anssi R. A. 
Published: December 2008

AbstractThe neural mechanisms involved in the detection of natural complex sounds were studied by recording single‐neuron responses from 132 cells in the primary auditory cortex of the cat. The cats were paralyzed and under neuroleptanalgesia (NLA). The cells were first stimulated with pure tones; the responses were then compared with those evoked by many different types of complex sounds, most of which were animal vocalizations. Per‐stimulus‐time (PST) histograms constructed from the responses to repetitive stimuli were compared with the corresponding sound spectrograms formed from the sounds used as stimuli. Of 100 cells 68 per cent gave predictable responses to complex sounds on the basis of their responses to different pure tone frequencies. In 32 per cent of the cells the responses were unpredictable. Half of these cells did not react to pure tones at all but responded to one or more animal vocalizations or generator sounds with different patterns. Some cells reacted to pure tones in quite a different way than to certain complex sounds, e.g. with inhibition instead of excitation. These results indicate that cells in the primary auditory cortex of the cat reacting in an unpredictable way to sounds with a complex structure have a more or less specialized function, in detecting and analyzing natural and other complex sound patterns. Cells reacting phasically to pure tones seem to be involved in the detection of transient sound elements.
Clearance of Some Quaternary Amines from the Spinal Subarachnoid Space*
Authors: Aquilonius S.‐M. , Winbladh B. , Zillén S. 
Published: December 2008

AbstractThe spinal subarachnoid space was perfused with artificial cerebrospinal fluid (CSF) from the low lumbar level to the middle thoracic level or to the cisterna magna in anesthetized rabbits. 3H‐choline, 3H‐methyl‐atropine or 3H‐decamethonium with carrier in different concentrations was added to the perfusate together with 14C‐inulin, the latter serving as a marker of the dilution of the perfusate by original CSF. Choline was eliminated from the perfusate partly by a saturable mechanism probably by an uptake into the spinal cord. About 15 per cent of the radioactivity of the choline infused was recovered from the spinal cord mainly as phosphorylcholine, betaine, and phospholipids. Amphetamine decreased the elimination of choline from ventriculocisternal perfusates and partly inhibited the uptake of choline in rabhit choroid plexus in vitro. In contrast, amphetamine did not influence the saturable elimination of choline in the lumbothoracic perfusion. Neither methylatropine nor decamethonium was eliminated from the perfusate by a saturable mechanism in the lumbothoracic perfusions. However, in perfusions including the cisterna magna methylatropine was partly eliminated by such a mechanism. The concentration of radioactivity in fourth ventricular choroid plexa suggested this structure to be responsible for the saturable part of the elimination. In conclusion, there is no active removal of quaternary amines in general from spinal CSF like the choroid plexus mediated clearance from ventricular CSF.
Brain Carbonic Acid Acidosis after Acetazolamide
Authors: Heuser Dieter , Astrup Jens , Lassen Niels A. , Betz Eberhard 
Published: December 2008

AbstractIn cats in barbiturate anesthesia extracellular pH and potassium were continuously recorded from brain cortex by implanted microelectrodes. Implantation of the electrodes preserved the low permeability of the blood‐brain‐barrier to HCO3and H+ions as indicated by the development of brainacidosisby i.v. injection of HCO3. Acetazolamide (25 mg/kg) i.v. was followed by a marked brain acidosis which after 10 min had progressed to a drop in pH of 0.203 ± 0.046 (x ± S.D., n = 8). The slowness of the development of acidosis points to a direct effect of the carbonic anhydrase inhibition on the brain tissue. As a further support for this conclusion was considered the finding of a prolonged responsetime of brain pH to HCO3i.v., to CO2inhalation, and to hyperventilation after the acetazolamide inhibition. No changes in brain extracellular potassium were found.
The Metabolism of Acetate in the Perfused Hind‐Quarter of the Rat
Authors: Karlsson N. , Fellenius E. , Kiessling K.‐H. 
Published: December 2008

AbstractThe elimination kinetics of acetate, the main end product of ethanol metabolism in the liver and the influence of acetate oxidation on the redox‐ and energy state of the isolated perfused hind‐quarter of the rat were studied. The rate of acetate uptake increased with increasing initial concentration of acetate in the perfusion medium, suggesting that the plasma level of free acetate may be one factor in the regulation of acetate uptake in the skeletal muscle. Addition of acetate as a single dose did not affect the net production of lactate or the uptake of glucose. In continuous infusion experiments at a constant concentration of 2 mM of acetate in the medium, the lactate/pyruvate ratio was unaffected in the medium and in the muscle tissue. Addition of acetate did not affect the oxygen uptake. Experiments with 14C‐acetate showed that about 50% of added radioactivity was found in form of 14CO2, accounting for 25 to 45% of the oxidative metabolism in the muscle tissue. It was calculated that about 25% of the acetate produced in the liver during ethanol oxidation can be consumed in the resting, perfused hind‐quarter of the rat. The tissue content of high‐energy phosphate compounds was not significantly affected by acetate
Incorporation of Leucine into Human Skeletal Muscle Proteins: A Study of Tissue Amino Acid Pools and their Role in Protein Biosynthesis
Authors: Lundholm K. , Scherstén T. 
Published: December 2008

AbstractThe in vitro incorporation of labelled leucine into human skeletal muscle proteins was studied with the aim to elucidate the relationship between the amino acid tissue pools and protein biosynthesis. The distribution volumes of leucine and cycloleucine in skeletal muscle tissue were similar but the equilibration time was shorter for leucine than for cycloleucine. The cellular uptake of leucine and cycloleucine was competitively inhibited by increased concentration of amino acids in the medium indicating an active transport. Optimal stimulation for incorporation of leucine into proteins was obtained at an amino acid concentration in the medium corresponding to 10 times that of normal human plasma. The incorporation of 14C‐leucine into skeletal muscle proteins was linear before the total pool of free intracellular 14C‐leucin had reached an equilibrium. The regression coefficients for the semilogarithmic plots of the labelling rate of proteins with 14C‐leucine and the incorporation rate of leucine calculated from the specific activity in the medium versus the amino acid concentration in the medium were different in the same experiment indicating a re‐utilization of amino acids released at protein degradation. The results are compatible with the hypothesis that the proteolytically released amino acids have a competitive advantage for incorporation as compared with extra‐ and intracellular free amino acids. It is concluded that the amino acid pool which is in the immediate continuity with the protein biosynthesis sites equilibrates rapidly with the extracellular amino acid pool.