bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Determining Stroke Volume during Intracoronary Adminstration of Calcium‐Gluconate and Isoproterenol
Authors: Bugge‐Asperheim B. 
Published: December 2008

AbstractBugge‐Asperheim, B. FACTORS DETERMINING STROKE VOLUME DURING INTRACORONARY ADMINISTRATION OF CALCIUM‐GLUCONATE AND ISOPROTERENOL. ACTA PHYSIOL. SCAND. 1973. 89. 249–259.The stroke volume (SV) response to inotropic stimulation of the heart has been studied in open‐chest dogs after implantation of an aortic flowmeter, pressure recording equipment, and piezo‐electric ceramics for measuring myocardial chord length (MCL) in the left ventricle. Following rapid injections of 1 fig isoproterenol or 100 mg calcium‐gluconate into the left coronary artery, myocardial contractility rose markedly, as evidenced by increases of 50–70 % in the rate of rise of left ventricular pressure (dP/dt) and aortic flow (dF/dt). The SV response was dependent upon left ventricular filling. At small ventricular volumes induced by reducing venous return, SV remained unchanged during inotropic stimulation. In dilated ventricles similar stimulation effected marked increases in SV. There was little difference in the increase in SV whether the left ventricle was dilated by increasing preload or afterload. End‐diastolic MCL decreased regularly during inotropic stimulation, but the decrease was smaller in a large than in a small ventricle. On the other hand, myocardial shortening (end‐diastolic MCL minus end‐systolic MCL) increased less in a small ventricle. It is concluded that the SV response to inotropic stimulation of the heart is primarily dependent on the end‐diastolic dimension of the left ventricle.
An Autoradiographic Study of the Intestinal Absorption of Palmitic and Oleic Acid
Authors: Haglund By Ulf , Jodal Mats , Lundgren Ove 
Published: December 2008

AbstractHaglund, U., M. Jodal and O. Lundgren. An autoradiographic study of the intestinal absorption of palmitic and oleic acid. Acta physiol. scand. 1973. 89. 306–317.The distribution of intraluminally incubated long chain fatty acids (LFA; ;3H‐palmitic acid, :3H‐oleic acid) within the intestinal villi were studied during in vivo conditions with an autoradiographic technique which prevented tracer losses from the tissue. The results show that LFA are fairly diffusely localized throughout the whole epithelial cell and, to some extent, also in the lamina propria after 1 or 20 min incubation. Intense vasodilatation or a 7% albumin solution administered intraluminally after the tracer incubation is able to “extract” a large amount of the absorbed LFA from the epithelial cells. These observations strongly suggest that LFA enter the epithelial cells faster than they are reesterified into triglycerides, resulting in a pool of diffusible LFA within the cells. Although the cells are in close contact with the subepithelial capillary network, any subsequent rapid absorption via the blood stream does not occur. It is proposed that the hindrance to net blood absorption of the lipid soluble LFA is a “short circuiting” of the easily diffusible LFA in the mucosal countercurrent exchanger.
Recurrent Control from Motor Axon Collaterals of la Inhibitory Pathways to Ventral Spinocerebellar Tract Neurones
Authors: Gustafsson B. , Lindström S. 
Published: December 2008

AbstractThe effects of impulses in recurrent motor axon collaterals on transmission in different inhibitory pathways to ventral spinocerebellar tract (VSCT) neurones were investigated in the cat by conditioning of IPSPs evoked in intracellularly recorded VSCT cells. Disynaptic IPSPs from large muscle spindle (la) afferenls were depressed in many but not all VSCT cells following an antidromic stimulation of ventral roots. The effect was found in VSCT neurones which themselves did not receive recurrent inhibition from motor axon collaterals. In cells with affected la IPSPs also some polysynaptic IPSPs evoked from ipsi‐ and contralateral group II muscle afferents and low threshold cutaneous afferents were depressed by a ventral root volley as well as disynaptic IPSPs from fibres descending on the ipsilateral side of the spinal cord. In unanesthetized preparations recurrent facilitatory potentials similar to those in motoneurones were evoked in VSCT neurones with la IPSPs. The findings indicate that some VSCT neurones receive collateral connexions from the interneurones which mediate la recipiocal inhibition to motoneurones and support the hypothesis that the VSCT conveys information about transmission in inhibitory reflex pathways to motoneurones (Lundberg 1971).
Projections to the Cat's Cerebral Cortex from Low Threshold Joint Afferents
Authors: Clark F. J. , Landgren S. , Silfvenius H. 
Published: December 2008

AbstractThe projections to the cerebral cortex from the contralateral low threshold afferents of the musculocutaneous branch to the elbow joint (Ejt) and the posterior knee joint nerve (Kjt) were investigated in cats anesthetized with chloralose. Graded electrical stimulation of the nerves was used to evoke the cortical potentials. Three discrete joint projection areas were found in the cytoarchitectonic area 3 of the posterior sigmoid gyrus, i.e. one Ejt and two Kjt loci. These loci overlapped with the projections from group I muscle afferents. One Ejt and one or two Kjt loci were observed in positions corresponding to cytoarchitectonic areas 1 and 2. They did not receive input from group I muscle afferents. A separate locus with overlap between forelimb joint and muscle afferents was located in area 4 y. Components 1 and II of the joint nerve volley evoked short latency potentials in all cortical loci. Low threshold cutaneous afferents evoked responses in all joint loci. The spinal course of the ascending Ejt path was mainly located in the dorsal column. Kjt component I afferents travelled mainly in the dorsal columns and component I and II afferents in the dorsolateral fascicle. The Kjt path in the dorsolateral fascicle ascended uncrossed to the level of Ci.
LDH Isozymes in Skeletal Muscles of Endurance and Strength Trained Athletes
Authors: Karlsson J. , Sjödin B. , Thorstensson A. , Hultén B. , Frith K. 
Published: December 2008

AbstractMuscle biopsy samples were obtained from arm and leg muscles of endurance and strength trained athletes, respectively. Total LDH activity as well as occurrence and activity of LDH isozymes were determined. Comparing the results from the athletes with those from non‐trained subjects with corresponding fibre compositions, it was found that the endurance athletes had a lower total LDH activity, a higher relative activity of the most heart‐specific isozymes, LDH (1 + 2), and, on electrophoretic separation, a complete absence of LDH (4 + 5) in both arm and leg muscles. As compared to the untrained material the strength trained athletes tended to have a higher total LDH activity, a similar distribution of relative isozyme activities, and, in the leg muscles, a strong electrophoretic band corresponding to LDH 5, the most skeletal muscle specific isozyme.
A Comparison between Direct and Indirect Measurements of Blood Flow in the Follicular Ovary of the Rabbit
Authors: Janson Per Olof , Selstam Gunnar 
Published: December 2008

AbstractA comparison was carried out between direct and indirect measurements of blood flow in follicular ovaries of anaesthetized laparotomized rabbits: Direct measurements by timed quantitative sampling of ovarian venous blood yielded blood flow values 3 times higher than those found with the use of 15 μm radioactive microspheres. However, when simulating the surgical trauma associated with direct measurements, the microsphere technique gave the same high ovarian flow values, indicating that this type of trauma caused ovarian hyperemia. It is concluded that direct measurements of blood flow, as performed in the present study, are unsuitable for investigations of circulatory events in the ovary. Mechanically induced ovarian vasodilatation is probably a factor which helps to explain the diverging data on blood flow obtained with direct and indirect methods. The radioactive microsphere technique appears to provide a means for reasonably reliable ovarian blood flow measurements in laboratory animals.
Regional and Single Glomerular Blood Flow in the Rat Kidney Prepared for Micropuncture. A Methodological Study
Authors: Källskog Ö. , Lindbom L. O. , Ulfendahl H. R. , Wolgast M. 
Published: December 2008

AbstractRegional renal and single glomerular blood flow was investigated in rats using 141‐Ce and 85‐Sr labelled microspheres. The kidneys were prepared for micropuncture and also the artery was catheterized with a steel cannula in order to make injections of 133‐Xenon and vasoactive substances selectively into one kidney. The microspheres were first separated by sedimentation into a narrow fraction and then injected as a plasma suspension into the carotid artery; the two batches were infused at half an hour intervals. Single glomeruli were sampled from kidney sections with the aid of silicon rubber casts allowing the identification of the glomeruli both with respect to their localisation and their postglomerular appearance. The results showed a relatively high blood flow in the superficial and juxtamedullary glomeruli of above 100 nl/min per 100 g rat whereas in the other glomeruli the blood flow was about 70 nl/min per 100 g rat. No differences could be observed between the right untouched kidney and the left prepared for micropuncture. Furthermore no discrepancies between the results from the two injections could be found. The data on the total renal blood flow obtained by the 133‐Xenon wash‐out method agreed well with the microsphere method.
Quantitative Studies of the Capillary Structure in the rete mirabile of the Eel, Anguilla vulgaris L.
Authors: Stray‐Pedersen Sverre , Nicolaysen Anne 
Published: December 2008

AbstractThe capillaries of the counter‐current capillary organ, rete mirabile, have been studied by light microscopy and electron microscopy. The vasculature of this rete was found to have a cross‐sectional area of about 5.25 mm2, and it consisted of 34000 efferent(= arterial)and 22 000 afferent(= venous) capillaries. The total surface area was the same for the two types of capillaries. The capillary endothelial cells showed numerous pinocytotic vesicles, scattered giant vacuoles and cytoplasmic extrusions (microvilli) at the luminal surface. The majority of the intercellular junctions appeared to have patent gaps with a width of 110–120 Å. The arterial capillaries appeared in many ways to be morphologically similar to skeletal muscle capillaries of mammals, whereas the fenestrated venous capillaries resembled those in the intestinal mucosa of mammals. Measurements of the ionic composition of the rete tissue indicated that the endothelial cells contained much less K+ than other cells, the rete containing approximately equimolar amounts of K+ and Na+. The functional significance of the structural and chemical observations are discussed.
The Effect on Total Renal and Tubular Function and Plasma Renin of a Moderate Isotonic Saline Load in Rats Anesthetized with Amytal and Inactin
Authors: Leyssac Paul P. , Frederiksen Ole , Skinner Sandford L. 
Published: December 2008

AbstractThe renal effects of i.v. saline loading equal to 1% body weight (b.wt.) were studied in 2 groups of rats:group Iwas anesthetized with Amytal (15 mg/100 g b.wt. plus supplementary doses),group IIwith Inactin (12.5–15.0 mg/100 g b.wt).In group Ithe saline load caused an increase in urine flow (+ 92%), solute excretion (+ 67%), inulin clearance (CIN) (+ 24%), PAH clearance (+ 31%) and absolute proximal reabsorption rate (+ 27%). Proximal fractional reabsorption and filtration fraction (FF) remained unchanged, while plasma oncotic pressure (COP) decreased by 10%. Plasma renin fell and there was an inverse relationship between renin concentration and proximal reabsorption rate. Ingroup IIurine flow and solute excretion increased after saline (+ 85% and 110%, respectively); CINand absolute proximal reabsorption rate was lower than in group I and failed to increase after saline. Proximal fractional reabsorption was also lower and decreased after saline. COP as well as renin decreased as in group I, but no relationship between renin concentration and proximal reabsorption rate could be demonstrated. The data indicate that Inactin depresses both resting proximal tubular reabsorptive capacity and the tubular response to a physiological volume expansion. The results are compatible with the hypothesis that the renin‐angiotensin system is significantly involved in regulation of proximal tubular function, while they are incompatible with the idea that peritubular COP plays any major role in this adjustment.
The Permeability of Fish Gills with Comments on the Osmotic Behaviour of Cellular Membranes
Authors: Steen Johan B. , Stray‐Pedersen Sverre 
Published: December 2008

AbstractThe permeability of eel gills to ions, lipid‐soluble and ‐insoluble substances has been measured under steady‐state conditions. The results obtained support the multi‐pathway model for transcapillary transport (Stray‐Pedersen and Steen 1975). The gills are 7.5 times more permeable to THO than to Na+ or K+. Metabolic inhibitors do not affect the transfer of substances across the gills. Exposure to EDTA or MS‐222 changes the permeability properties to resemble those of an aquous barrier. The gills are 10 times less water permeable than the capillaries of the rete mirabile.
Effects of Catecholamine‐Infusions and Hypoxia on Pulmonary Blood Volume and Extravascular Lung Water Content in Cats
Authors: Aarseth P. , Karlsen J. , Bø G. 
Published: December 2008

AbstractThe effects of catecholamine‐infusions and of hypoxia on lung blood volume and on extravascular lung water content have been studied in anesthetized cats with opened chests. To this end a biopsy technique, with isotope labelling of blood and with successive removal of the smaller lung lobes, was employed. Mean pulmonary arterial pressure increased by 30–75% upon infusing catecholamines or upon inducing general hypoxia, the latter stimulus being the more powerful one. Pulmonary blood volume did not increase during these procedures, where an active constriction of pulmonary vessels thus apparently took place. The extravascular lung water content was found to be reduced in animals infused with noradrenaline or ventilated by hypoxic air, whereas a small increase was observed in the animals receiving adrenaline. This difference might reflect domination of precapillary vasoconstriction in the former groups, whereas post‐capillary vasoconstriction could be more pronounced with adrenaline.
The Importance of Asphyxia for the Development of Diving Bradycardia in Ducks
Authors: Blix Arnoldus Schytte 
Published: December 2008

AbstractUpon submersion, the domestic duck normally displays a prompt but modest cardiac retardation, which, after a short delay, is reinforced into a pronounced state of bradycardia. The present study has revealed that arterial asphyxia is a prerequisite for the reinforcement of the initial slight bradycardia.
Metabolic Characteristics of Fibre Types in Human Skeletal Muscle
Authors: Essén B. , Jansson E. , Henriksson J. , Taylor A. W. , Saltin B. 
Published: December 2008

AbstractMuscle biopsy samples were obtained from healthy subjects in order to evaluate quantitative differences in single fibres of substrate (glycogen and triglyceride) and ion concentrations (Na+ and K+) as well as enzyme activity levels (succinate‐dehydrogenase, SDH; phosphofructokinase, PFK; 3‐hydroxyacyl‐CoA‐dehydrogenase, HAD; myosin ATPase) between human skeletal muscle fibre types. After freeze drying of the muscle specimen fragments of single fibres were dissected out and stained for myofibrillar‐ATPase with preincubations at pH's of 10.3, 4.6, and 4.35. Type I (“red”) and II A, B, and C (“white”) fibres could then be identified. Glycogen content was the same in different fibres, whereas triglyceride content was highest in Type I fibres (2–3 × Type II). No significant differences were observed for Na+ and K+ between fibre types. The activity for the enzymes studied were quite different in the fibre types (SDH and HAD, Type I ≊ 1.5 × Type II; PFK Type I ≊ 0.5 × Type II; Myosin ATPase Type I ≊ 0.4 × Type II). The subgroups of Type II fibres were distinguished by differences in both SDH and PFK activities (SDH, Type II C > A > B; PFK, Type II B > A ≊ C). It is concluded that contractile and metabolic characteristics of human skeletal fibres are very similar to many other species. One difference, however, appears to be that no Type II fibres have an oxidative potential higher than Type I fibres.
The Influence of Rheological and Collapse Factors on Pre‐ and Post‐Capillary Flow Resistances in the Skeletal Muscle Vascular Bed of the Cat
Authors: ÖBerg Bengt , Little Rod , Rippe Bengt , Folkow Björn 
Published: December 2008

AbstractThe importance of passive‐elastic changes of vascular dimensions and shifts in regional effective viscosity for the pre‐/postcapillary resistance ratio (RA/RV), and hence mean capillary pressure (PC), was analyzed in cat calf muscles. Reductions of mean venous distending pressure below 6–8 mm Hg induced marked R, increases due to escalating venous collapse. This mechanism tends to delimit the PC reductions and rate of transcapillary fluid absorption during intense precapillary vasoconstriction. Comparisons of RA/RVfor erythrocyte suspensions (Hct 40–50) and cellfree perfusates at identical vascular dimensions showed that RA/RV was considerably higher, and P, correspondingly lower, for the erythrocyte suspension except at very low flows. This RA/RV difference increased with increasing flow and at very high flows P, was about 10 mm Hg lower during perfusion with the erythrocyte suspension. These findings apparently diverge from the known influence of tube radius and linear flow velocity on effective in vitro viscosity of blood. Since distal precapillary and proximal capillary sections, both having smaller diameters than the erythrocytes, are located upstream to the point of filtration‐absorption equilibrium, they contribute in this respect to RA. It is therefore suggested that the increasing RA/RV with erythrocyte perfusion, particularly at higher flows, is not due to genuine viscosity factors but to friction losses when cells in “bolus flow” are squeezed through the narrowest precapillary sections.
Kinetics of the Glomerular Ultrafiltration in the Rat Kidney. A Theoretical Study
Authors: Källskog Ö. , Lindbom L. O. , Ulfendahl H. R. , Wolgast M. 
Published: December 2008

AbstractThe glomerular filtration process was evaluated theoretically from micropuncture data obtained from Sprague‐Dawley rats. The hydrostatic pressures in the glomerular capillaries and Bowman's space minus the oncotic pressure in systemic plasma gave the net driving force at the proximal end of the glomerular capillary. From the single nephron filtration fraction the mean net driving force over the glomerular membrane was calculated to be 20 mm Hg during normotension, decreasing to 12 mm Hg during a perfusion pressure of 80 mm Hg. The hydraulic permeability for one glomerulus was 0.7‐0.8 nl/min. 100g b. wt. mmHg. The pressures at the distal end of the glomerular capillaries were 13 and 6 mm Hg under the above two conditions, indicating non‐equilibrium of the filtration process at the end of the glomerular capillary. It was shown that the glomerular filtration rate is mainly influenced by the driving pressures. During hypotension an increased plasma flow dependency was evident. Brenner et al. found a filtration equilibrium and a plasma flow dependent glomerular filtration rate in a mutant Wistar rat strain. The discrepancy between their results and ours is due to the low glomerular plasma flow and hydrostatic pressures in the Wistar rats. It is concluded from our results that both pre‐ and postglomerular resistances may influence the glomerular filtration rate and glomerular plasma flow independently.
Quantitative Aspects of the Vagal Control of Gastrin Release in Cats
Authors: Uvnäs‐Wallensten K. , Uvnäs B. , Nilsson G. 
Published: December 2008

AbstractGastrin concentrations were measured in the gastric blood of eviscerated cats. Blood flow was recorded concomitantly thus enabling quantitative determination of the gastrin output. Electrical vagal stimulation within the “physiological” frequency range (0.5–3 Hz) did not regularly result in any detectable changes in the peripheral gastrin level but an increase in this level was always observed on stimulation with frequencies above 3 Hz. A constant gastrin release per stimulus was then obtained, as long as the total number of vagal stimuli did not exceed 2000–3000. A larger number of impulses resulted in rapid fatigue of the release mechanism, indicating either a rapid and sustained fatigue of the neural control mechanism or the existence of a rather small pool of gastrin for immediate release—amounting to less than one per cent of the total antral store of immunoreactive gastrin. The rate at which such a releasable pool was refilled would suffice to compensate for the depletion induced by vagal stimuli at physiological frequencies, i.e. < 3–4 Hz only. The two vagi innervate separate gastrin pools, which behave independently as far as release and refilling are concerned.
The Effect of Progesterone and of Insulin Administration on Regional Adipose Tissue Cellularity in the Rat
Authors: Krotkiewski Marcin , Björntorp Per 
Published: December 2008

AbstractFemale rats were given progesterone in a high and a low dose or insulin by injection. Both hormones caused hyperinsulinemia and an elevated body weight, explainable by increased fat tissue weight, which in turn was due to an increased fat cell size. There was a regional specificity of these effects for both procedures. It was therefore concluded that adipose tissue does not react as a homogenous tissue to different stimuli. Although not definitely conclusive because of difference in the degree of hyperinsulinemia the results also indicate that the effects of insulin are primarily exerted on the small fat cells of the subcutaneous region while progesterone increased the size of the larger parametrial fat cells.
Effects of pressure on fast axoplasmic flow. An in vitro study in the vagus nerve of rabbits
Authors: Hahnenberger Rudolph W. 
Published: December 2008

AbstractBy using a radially directed stream of fluid it is possible to compress a section of a nerve in vitro by known pressures without interrupting the supply of oxygen and nutrients to the nerve. Motor neurons of the vagus nerves of rabbits labelled with SH‐leucine were used at room temperature. When a nerve was subjected to 20 mmHg pressure fast axoplasmic flow was not altered, but at 30 mmHg there was a slight but consistent inhibition, which was even more marked at 60 mmHg and still more at 90 mmHg. The pressure induced block of axoplasmic flow was reversible when 60 mmHg pressure was applied for as long as 4 h, when the nerves were compressed for 15 h there was reversibilkty in only 5 out of 8 cases.