bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Prolonged Strenuous Exercise on the Concentration of Triglycerides, Phospholipids and Glycogen in Muscle of Man
Authors: Fröberg Sven O. , Mossfeldt Folke 
Published: December 2008

AbstractMuscle tissue from the lateral vastus of the femoral muscle was taken by needle biopsy technique in 7 male subjects before and after strenuous exercise by skiing for about 7 hrs. The mean muscle triglyceride concentration decreased from 17 to 8 μmoles/g wet weight during the exercise. No change was observed in the phospholipid concentration. The mean glycogen concentration in the muscle decreased from 16 to 7 mg/g sswet weight during the exercise. The results indicate that not only muscle glycogen but also muscle triglycerides are of importance for the energy metabolism in man during exercise.
Effect of Prolonged Physical Training on the Catecholamine Levels of the Heart and the Adrenals of the Rat
Authors: ÖStman Ingegerd , Sjöstrand Nils O. 
Published: December 2008

AbstractThe effect of prolonged physical training on the noradrenaline content of the heart and the catecholaniine content of the adrenal glands was studied on rats. the trained rats showed a moderate but highly significant cardiac hypertrophy (heart weight of controls: 1.32±0.01, trained rats: 1.41 ±0.01, heart ratio (g heart weight/100 g b.w.) of controls: 0.29 ± 0.003, trained rats: 0.34 ± 0.003). There was no difference in cardiac noradrenaline concentration between trained and untrained rats (controls: 0.69±0.04 μg/g, trained rats: 0.73±0.03 μg/g). There was a highly significant increase in adrenaline content of the adrenal glands espressed as μg adrenaline/kg b.w. (Controls 93±5 μg/kg, trained rats: 122 ± 5 μg/kg). It is concluded that prolonged physical training does not lower the amounts of synipatlictic trans mitter of the heart. It is further suggested that an increased adrenaline content in the adrenal glands might be a manifestation of an adaptation to the increased demands upon the rardio vascular system in rats subjccted to prolonged physical training.
Efflux of Prostaglandin E, from Cat Paws Perfused with Compound 48/80
Authors: ÄNggård Erik , Strandberg Kjell 
Published: December 2008

AbstractEffluents from cat paws perfused with compound 48/80 contained histamine and lipid‐soluble smooth muscle stimulating principles. Fractionation of the lipid‐soluble material on silicic acid resulted in a separation into two major components with different biological properties. One component was of polar character and elicited a slow, sustained contraction of the isolated guinea‐pig ileum. These are effects associated with “slow reacting substance” (SRS) by definition. The other component being less polar was examined by a variety of chromatographic procedures in combination with bioassay. In silicic acid chromatography with linear gradient elution and in reversed phase partition chromatography all biological activity followed the radioactivity due to added 3H‐labelled prostaglandin E2 (PGE2). On thin layer chromatography the smooth muscle stimulating compound cochromatographed with reference PGE2. When the spasmogenic compound isolated by silicic acid chromatography was incubated with 15‐hydroxy prostaglandin dehydrogenase from swine lung in the presence of NAD+ complete biological inactivation occurred. Determination of ester‐bound C20 fatty acids in cat skin by gas chromatography revealed that arachidonate, precursor of PGE2, was the most abundant prostaglandin precursor acid. When 3H‐PGE2 was infused into cat paws the parent compound as well as two metabolites, 13,14‐dihydro‐PGE2 and 15‐keto‐13,14‐dihydro‐PGE2, appeared in the effluent. It is concluded that PGE2 constitutes part of the lipid‐soluble spasmogenic material appearing in connection with histamine release in the cat paw induced by compound 48/80.
The Quantitative Inhibition of Triton Lipemia with Heparin in Rats
Authors: Haikonen Matti , Räsänen Toimi , Räsänen Vesa , Taskinen Eero 
Published: December 2008

AbstractThe effect of exogenous heparin on triton lipemia induced in rats was studied in 2 expts. 5×25 mg of Triton WR‐1339 injected at intervals of 12 hrs caused an abrupt increase in the blood cholesterol and fat levels. They were both lowered distinctly by 50 IU of heparin injected concomitantly with triton. In the second experiment, 3×25 mg of triton provoked a smaller but significant elevation in the lipemia of rats. 3 × 250 IU of heparin nullified the hypercholesterinemia and the lipemia completely. Smaller doses of heparin caused a gradually diminishing inhibition of triton induced lipemia. The results of these two experiments and one of our earlier experiment suggest that Triton WR‐1339 inhibits the release of heparin especially from the mucosal mast cells of gastrointestinal tract. Triton does not inhibit the activation of the clearing factor with exogenous heparin. Under these circumstances, it is possible to measure the shortage of endogenous heparin by replacing it with exogenous heparin using the level of lipemia as indicator.
Purification and Properties of the Slow Reacting Substance Formed in the Cat Paw Perfused with Compound 48/801
Authors: Strandberg Kjell , Uvnäs Börje 
Published: December 2008

AbstractCat paws were perfused with a physiological salt solution containing compound 48/80. In addition to histamine, a principle producing a slow sustained contraction of the isolated guinea‐pig ileum appeared in the effluent. This slow reacting substance (SRS) was purified by ethanol extraction, solvent partition, silicic acid and anion exchange chromatography. The overall recovery was 10–20 per cent, calculated from the non‐histamine smooth muscle stimulating activity of the ethanolic extract. The purification calculated from the crude lipid extract was about 200‐fold. The purified material was dialysable, thermostable at neutral pH and more labile in acid than in alkaline milieu. It behaved homogenously on thin layer chromatography in several systems. The most marked biological effects were contraction of the isolated guinea‐pig ileum and the human bronchus, increases in the bronchial resistance in guinea‐pigsin vivo, in the colouration (Evan's blue dye i.v.) of guinea‐pig skin after intradermal injection and in the blood flow in the cat hindlimb after intraarterial injection. Treatment of the purified material with N, N'‐carbo‐di‐p‐tolylimide, phenyl isocyanate, iodine monobromide, potassium permanganate or acetic anhydride abolished or greatly reduced the biological activity. Incubation of SRS with 15‐hydroxy prostaglandin dehydrogenase in the presence of NAD+resulted in no loss of biological activity. Together the results indicate that SRS is a biologically active carboxylic acid with hydroxyl groups and one or more double bonds but probably of non‐prostaglandin nature.
Hyperosmolarity and Pulmonary Vascular Capacitance
Authors: Bø G. , Nicolaysen G. 
Published: December 2008

AbstractSince plasma osmolarity rises during general muscle exercise and the lung is thought to have a function as a blood depot we have investigated the effect of plasma hyperosmolarity on pulmonary vascular capacitance. Hyperosmolar solutions of sodium chloride, urea and ethylene‐glycol (listed in order of potency) were infused into the pulmonary artery of an isolated rabbit lung preparation perfused with plasma at constant volume pulsatile inflow and ventilated by positive pressure. All the test‐substances caused dose‐dependent reductions in the weight of the preparations, which was followed continuously by the use of a force transducer. The effect was not related to change in bronchomotor tone or pulmonary vascular pressures. Nor could the weight reductions be explained solely as a result of loss of water from the lungs. The capacitance vessels of the lung appear to constrict when exposed to increased plasma osmolarity, a response which is in direct contrast to the effect of this stimulus on the resistance vessels of the lung. The finding strengthen the concept of the lung as a blood depot.
Ultrastructural Studies of the Alveolar‐Capillary Barrier in Isolated Plasma‐Perfused Rabbit Lungs. Effects of EDTA and of Increased Capillary Pressure
Authors: Hovig T. , Nicolaysen Anne , Nicolaysen G. 
Published: December 2008

AbstractThe ultrastructure of lung capillaries and of lung interstitiuni has been studied in isolated. ventilated and plasma‐perfused rabbit lung preparations at different levels of perfusate [Ca++] and [Mg++] (achieved by EDTA additions). A perfusion fixation niethod was applied, and situations where net fluid transfer over the capillary wall was taking place could therefore be studied with some confidence. No morphological changes were found which could explain the increased capillary permeability to proteins during EDTA‐induced edema development. Ultra‐structural alterations of the capillary walls were similarly not observed during periods of increased hydraulic conductivity of the lung capillaries caused by lower concentrations of EDTA than those releasing edema. In all experiments where net outward flux of fluid from the capillaries had taken place at the moment of fixation, one could observe electron lucent zones (laminae rarae) of the basement membranes which were much more distinct than in control specimens. This phenomenon could be related to the process of capillary fluid leakage, which thus may take place also in the regions of the vessel wall wheie the alveolar‐capillary barrier is at its thinnest.
Stability of [Mg2+] in Cerebrospinal Fluid during Plasma Changes and during Hypercapnia in Young and in Adult Rats
Authors: Olsen O. M. , Sørensen S. C. 
Published: December 2008

AbstractThis investigation was undertaken to examine whether the rat, like other mammals that have been studied, maintains a stable concentration of Mg2+ in cerebrospinal fluid (CSF) when the plasma Mg2+ concentration is changed. CSF was sampled from the cisterna magna in adult rats made hypomagnesemic by being fed a magnesium‐free diet. The [Mg2+] in CSF did not decrease significantly during hypomagnesia, in disagreement with previous findings in the rat. The disagreement could have been due to a difference in the age of the animals when they were studied, cation transport processes possibly being incompletely developed in young rats, but we found that rats 3 to 4 weeks old also maintained a stable [Mg2+] in CSF during hypo‐niagnesemia. The effect of 4 hrs of hypercapnia on the [Mg2+] in CSF was examined in normal hypomagnesemic adult rats. Hypercapnia did not affect the [Mg2+] in CSF in either group.
Ca++ Dependence of Histamine Release and Formation of Slow Reacting Substance in the Cat Paw
Authors: Strandberg Kjell 
Published: December 2008

AbstractThe influence of divalent cations on the release of histamine and the formation of slow reacting substance (SRS) in the perfused cat paw induced by compound 48/80 was studied. Ca++ was found to have a stimulatory effect on both processes. Ca++ had no releasing effects per se. When the paws were perfused for 1 or 2 hrs with Ca++‐free salt solution, prior to compound 48/80, the release was depressed. Histamine release and formation of SRS were inhibited by disodium ethylene diamine tetraacetate (EDTA). In both instances the EDTA‐blockade could be reversed by Ca++, whereas Ca++, Mg++, Mn++ and Ni++ were ineffective substitutes. The EDTA‐blockade of histamine release but not that of the formation of SRS was also reversed by Sr++ and in some experiments by Ba++. The stimulatory effect of Sr++ on the release of histamine was weaker than that of Ca++. No significant stimulatory effect of Sr++ on the formation of SRS was observed. It is concluded that the release of histamine and the formation of SRS in the cat paw are Ca++‐dependent processes although in the case of histamine release Ca++ can partially be replaced by Sr++.
Changes in Cerebral Blood Volume of Mice at Various Time‐Periods after Superior Cervical Sympathectomy
Authors: Edvinsson L. , Owman Ch. , West K. A. 
Published: December 2008

AbstractThe relative blood volume in the brain of mice was estimated after distribution in the blood stream of intravenously administered131I‐labelled human serum albumin. The alterations in the blood volume was studied at various time‐periods after bilateral excision of the superior cervical ganglia. The blood volume was found to remain unchanged during the first 6 hrs post‐operatively. At 12 hrs it was reduced by 28 per cent, whereas after 24 hrs it had increased to a level 34 per cent above that in the unoperated control animals. The volume then normalized at 4 days after sympathectomy, and even tended to be subnormal after 2 weeks. It is suggested that the initial reduction in blood volume is caused by vasoconstriction as a result of the leakage of noradrenaline from the vascular adrenergic nerve terminals starting a few hours after sympathectomy. The resulting degeneration activation of the smooth muscle receptors is known to subside within about 24 hours at which time a vasodilatation was found to occur. It is probable that the vascular tone then returned to the preoperative or an even more pronounced degree due to the progressive development of supersensitivity of the denervated vascular receptors to normally circulating catecholamines.
The DC Potential between CSF and Plasma in Respiratory Acidosis
Authors: Messeter Kenneth , Siesjö Bo K. 
Published: December 2008

AbstractThe electrical DC potential between cisternal cerebrospinal fluid and jugular venous blood was measured in rats during respiratory acidosis and alkalosis. In one of the main series studied, respiratory acidosis and alkalosis was upheld for 5, 15, 45 and 180 min in animals anesthetized with nitrous oxide. In the other main series, sustained hypercapnia was induced by exposing unanesthetized rats to about 5 or about 11% CO2 for 3, 24 and 48 h, respectively. In this series, the animals were anesthetized during the last 30–45 min of the hypercapnia. In acute respiratory acidosis and alkalosis, the CSF‐plasma potential difference varied linearly with the plasma pH with a slope of about ‐27 mV/pH unit. The CSF‐plasma potential differences measured in sustained hypercapnia did not deviate significantly from the mean regression line calculated from the acute experiments. The results thus showed that the CSF‐plasma potential difference was not only increased during acute respiratory acidosis, but also remained increased as long as the plasma pH was acid.
Changes in Continuously Recorded Intracranial Pressure of Conscious Rabbits at Different Time‐Periods after Superior Cervical Sympathectomy
Authors: Edvinsson L. , Owman Ch. , West K. A. 
Published: December 2008

AbstractThe intracranial pressure, measured as the ventricular fluid pressure (VFP), was recorded continuously during about 2 days via a cannula inserted into the left lateral ventricle of the brain of conscious rabbits. The effect of bilateral removal of the superior cervical ganglia on the VFP was studied at various time‐periods after operation, and the results were compared with those from unoperated control animals. The pressure changes attributed to the sympathectomy are referred to as the net VFP. The operation ultimately caused a disappearance of noradrenaline from intracranial sympathetic nerves. The net VFP was not affected during an 8‐hr period of the recording starting 5–8 hrs after sympathectomy. During the following 35 hrs it was reduced by approximately 25 mm physiological saline followed by a return to initial or somewhat higher levels. Four days after sympathectomy the net VFP was significantly increased throughout the recording period. Two weeks after the operation the pressure had returned to the same, or even lower level compared with the non‐sympathectomized control animals. The variations in the net VFP at different time‐periods after sympathectomy are considered to reflect mainly changes in the intracranial vascular bed due to the leakage and disappearance of the noradrenaline transmitter from the degenerating nerve terminals followed by denervation supersensitivity. The results are discussed in terms of a sympathetic influence on the intracranial pressure mediated through the volume of the intracranial vascular bed, and/or the cerebrospinal fluid production in the choroid plexuses.
Nervous Influence on the Pulmonary Capacitance Vessels in the Rat
Authors: Aarseth Petter 
Published: December 2008

AbstractIt has previously been shown in experiments on rats that the pulmonary capacitance vessels play an important role as a blood depot in this species. In the present experiments one has attempted to evaluate the vasomotor nervous influence on this depot. Pulmonary blood volume was estimated from measurements of 128I‐tagged albumin and 51Cr‐tagged erythrocytes in the excised lungs of rats which had been rapidly frozen in liquid nitrogen. Partial pulmonary denervation was achieved beforehand in two groups of animals by cutting the left thoracic vago‐sympathetic nerve trunk. Animals from one of these groups were frozen without further treatment, whereas those from the other group were exposed to a standardized blood loss immediately before being immersed in liquid nitrogen. When compared to the situation in control animals the left lung from animals of both the above groups contained relatively more blood than did their right lung. Furthermore the total pulmonary blood volume was found to be increased in animals with such partly denervated lungs. The reduction in pulmonary blood volume observed subsequent to a blood loss, was less marked in animals where the left vago‐sympathetic nerve trunk had been cut than in animals with intact pulmonary innervation. It is concluded that the pulmonary blood volume in the rat is influenced through vasomotor nerves both when a blood loss has taken place and during normal circulatory conditions.
Effect of Reduced Perfusion Pressure on Intrarenal Distribution of Blood Flow in Dogs
Authors: Løyning E. W. 
Published: December 2008

AbstractExperiments by Barton et al. (1968) and Hollenberg et al. (1968) suggested that renal sodium excretion may be regulated by the distribution of blood flow within the kidney. Such a mechanism might account for the reduction in sodium excretion during lowering of arterial perfusion pressure, despite constant glomerular filtration rate and total renal blood flow (RBF). In the present study, renal blood flow in the outer half of the cortex (OCF) and inner half of the cortex (ICF), and in outer medulla (MBF), was examined during reductions of mean renal arterial pressure (RAP). RAP was reduced in steps by a clamp on the aorta or the renal artery, and at each pressure reduction OCF and ICF (cortex group, 7 dogs) and MBF (medulla group, 11 dogs) were measured by polarographic recording of hydrogen gas clearance with platinum electrodes inserted in the cortex, 2–3 mm and 6–7 mm respectively, and in outer medulla. RBF was measured by an electromagnetic flowmeter. At control pressure, OCF averaged 3.26 ml/min · g and ICF 3.45 ml/min · g, the difference between them being insignificant. An average decrease in RAP from 131 mm Hg to 76 mm Hg caused a 1% decrease in RBF and decreases in OCF and ICF to 89% (range 77–98%) and 87% (range 75–94%) respectively, both in per cent of control. The difference between OCF and ICF during clamping was not significant. At an average decrease in RAP from control of 126 mm Hg to 88 mm Hg, RBF decreased to 96% of control; MBF was not reduced (range 81–116%). The difference between changes in MBF and RBF was not significant. Atropinization did not change the pressure‐flow relationship of outer medulla.
Studies of Monosaccharide Permeability of Arterial Tissue and Intestinal Smooth Muscle; Effects of Insulin
Authors: Arnqvist Hans J. 
Published: December 2008

AbstractThe permeability of C14‐labelled D‐xylose and the accumulation of D‐glucose‐C14 were studied in rat and rabbit aorta and rabbit colon smooth muscle. C14‐labelled sucrose and sorbitol were used to estimate the extracellular space. In rabbit colon the distribution of sucrose‐C14 and sorbitol‐C14 reached an equilibrium after 30 min and were confined to about 40–50% of wet tissue weight. The initial distribution of D‐xylose‐C14 and D‐glucose‐C14 was the same as that of sucrose‐C14 and sorbitol‐C14 but reached no equilibrium after 30 min, instead there was a gradual increase which persisted for at least 150 min. The same results were obtained in rat and rabbit aorta. These findings indicate that D‐glucose and D‐xylose can penetrate the smooth muscle cell membrane, while sorbitol and sucrose are confined to the extracellular space. When rabbit colon was incubated for 60–180 min in D‐glucose‐C14 there was a continuous rise of tissue activity which exceeded a distribution in the extracellular space. The tissue concentration of unlabelled D‐glucose determined by an enzymatic method was constant during the same incubation times and corresponded to a distribution in the extracellular space. It seems probable therefore that the membrane permeability of D‐glucose is rate limiting for the metabolism of glucose in the smooth muscle cells.Insulin (0.1 U/ml) increased moderately the accumulation of C14‐labelled D‐glucose in rat aorta and rabbit colon and the accumulation of D‐xylose‐C14 in rabbit colon.
The Action of Progesterone Derivatives and Other Steroids on the Sodium Transport of Isolated Frog Skin
Authors: Tomlinson R. W. S. 
Published: December 2008

AbstractThe ability of certain progesterone derivatives to inhibit the sodium transport of isolated frog skin has been compared relative to progesterone. Small changes in the steroid molecular structure reduces or abolishes its ability to cause inhibition. Cortisol produces similar effects to those already reported for aldosterone. Desoxycorticosterone exhibits the effects of both progesterone and aldosterone. 17B‐estradiol produced a stimulation and cortisone, pregnenolone, testoterone and estrone had no obvious effect.
On the Mechanism of Chlorpromazine‐Induced Histamine Release from Rat Mast Cells
Authors: Frisk‐Holmberg Marianne 
Published: December 2008

AbstractOn exposure to chlorpromazine in concentrations above 20 μM, histamine was released by rat mast cellsin vitro.Histamine release was unaffected by metabolic inhibitors, but was reduced by tetrodotoxin, elevated extracellular K+and Ca++concentrations. The cellular ratio of Na+and K+was changed, after treatment with chlorpromazine; sodium entered and potassium left the mast cells. It is concluded that chlorpromazine‐induced histamine release is secondary to permeability changes in the mast cell membranes and that Na+plays an important part in the release mechanism.
Adrenergic Innervation and Drug Responses of the Oval Sphincter in the Swimbladder of the God (Gadus morhua)1
Authors: Nilsson Stefan 
Published: December 2008

AbstractThe effects of drugs and of electrical stimulation of nerves on the circular and radial smooth muscles of the oval sphincter in the cod swimbladder have been studied. Opening of the oval seems to be caused by liberation of noradrenaline from vagal fibres in the muscularis mucosae. The noradrenaline relaxes the circular muscles by a beta effect, and contracts the radial muscles by an alpha effect. Acetylcholine contracts both circular and radial muscles, but no definite evidence for the existence of cholinergic fibres have been obtained. Closing of the oval may occur due to lack of adrenergic impulses. Adrenergic varicose nerve fibres have been observed running in both circular and radial muscle bundles, by use of a fluorescent histochemical method.