bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bronchial Effects of Some Prostaglandin E and F Analogues
Authors: Strandberg Kjell , Hedqvist Per 
Published: December 2008

AbstractThe effects of some analogues of PGE1, PGE2and PGF2α, rendered less accessible to the action of prostaglandin dehydrogenase by having methyl groups at carbons 15 and/or 16, or a phenyl group at carbon 17, on the tracheobronchial insufflation pressure in guinea pigs and on the tone of isolated human bronchi were investigated. Regardless of route of administration, i.v. injection or aerosol administration, PGE1,16,16‐dimethyl‐PGE1, PGE2, the methyl esters of 15(R)15‐methyl‐PGE2and 15(S)15‐methyl‐PGE2, 16,16‐dimethyl‐PGE2and its methyl ester, and 17‐phenyl PGE2all produced a dose‐dependent inhibition of the histamine‐induced increase in insufflation pressure and a fall in systemic blood pressure in the anesthetized guinea pig. Although the duration of action of the PGE‐analogues was longer than that of the parent compounds, none of them was more potent with regard to the peak effect produced on insufflation pressure. Of the PGF2αanalogues studied, 16,16‐dimethyl‐PGF2αwas the most potent compound, in decreasing rank order followed by 15(S)15‐methyl‐PGF2α, 17‐phenyl‐PGF2αand PGF2α, in eliciting an increase in insufflation pressure on i.v. injection. On aerosol administration, only 16,16‐dimethyl‐PGF2αcompound was more potent than PGF2αOn isolated human bronchi, PGE1and PGE2were consistently relaxant, although in some expts. the relation to PGE2was followed by constriction. The 16,16‐dimethyl analogues of PGE1and PGE2were consistently bronchoconstrictor whereas the effects of the other PGE–analogues were weak and inconsistent. In comparison with the bronchorelaxant β2‐adrenoceptor stimulating compounds, the PGEs and PGE‐analogues studied do not have any outstanding features and may even imply a risk in clinical practice.
Muscle Spindle Activity in Man during Standing
Authors: Burke David , Eklund Göran 
Published: December 2008

AbstractIn standing human subjects, muscle spindle activity was recorded from peroneal nerve fascicles innervating anterior compartment muscles. Provided that the receptor‐bearing muscle remained relaxed, the basal activity and responses to stretch seen in multi‐unit and single unit afferent recordings were stable and not altered by eye‐closure or assistance to balance. The discharge frequencies of single afferent fibres were similar to those recorded at comparable muscle lengths in relaxed reclining subjects. By analogy to findings in reclining subjects, these results suggest that, during standing, the background fusimotor drive to relaxed muscles is negligible. Backward body sway can induce a sway‐stabilizing reflex contraction in the muscles of the anterior compartment. Such reflex contractions were accompanied by increased muscle spindle activity, the intensity of which appeared to be related to the intensity of the skeletomotor contraction. When balance was assisted by holding a support, swaying movements of similar or greater amplitude and velocity did not produce reflex activity, and the spindle response was of low frequency. It is concluded that the sway‐stabilizing reflex contraction operates in alpha‐gamma linkage, and that these contractions are not generated by segmental stretch reflex pathways.
Glycogen Synthetase and Phosphorylase Activity in Slow and Fast Twitch Skeletal Muscle Fibres in Man
Authors: Piehl Karin , Karlsson Jan 
Published: December 2008

AbstractGlycogen synthetase (I + D) and phosphorylase (á+b) activity was determined in human skeletal muscle biopsies with different muscle fibre composition and in dissected and pooled batches of the two main muscle fibre types: slow twitch (ST) and fast twitch (FT), respectively. Glycogen synthetase (I + D) activity remained unchanged as the per cent of FT fibres increased, but phosphorylase (á+b) activity was found to increase. A similar activity pattern was found in dissected and pooled FT fibres as compared to ST fibres, i.e. the same glycogen synthetase activity but heightened phosphorylase activity.
Comparative Effects of Adrenaline and Felypressin (Oetapressin) on Consecutive Sections of the Vascular Bed in Canine Adipose Tissue
Authors: Burcher Elizabeth , Olgart Leif , Gazelius Bertil 
Published: December 2008

AbstractBlood flow and tissue volume were recorded in the isolated canine subcutaneous adipose tissue, enclosed in a plethysmograph. Adrenaline and felypressin (oetapressin) were infused intra‐arterially at doses producing a blood flow reduction of approximately 60%. Adrenaline (4.6–23 ng/min) caused an initial reduction in tissue volume, indicating a constriction of capacitance vessels. Octapressin (0.46–9.2 ng/min) had no effect on tissue volume. Neither adrenaline or octapressin caused appreciable filtration or absorption, suggesting that the pre‐ to postcapillary resistance ratio remained unchanged. In contrast to sympathetic stimulation and noradrenaline, adrenaline significantly reduced the capillary filtration coefficient (CFC) by 34%, the change in CFC being related to the flow reductions, while octapressin did not reduce CFC significantly. On the basis of these results it is suggested that the constrictor effect of adrenaline on precapillary sphincter sections and on capacitance vessels is greater than that of octapressin in doses producing similar flow reductions.
Muscle Adaptation to Extreme Endurance Training in Man
Authors: Jansson E. , Kaijser L. 
Published: December 2008

AbstractTo evaluate the effect of extreme endurance training on muscle fibre composition and activities of oxidative enzymes in different fibre types biopsies were taken from vastus lateralis, gastrocnemius and deltoideus of elite orienteers. Comparisons were made between the (trained) leg muscles and the (relatively untrained) arm muscles, and with leg muscles of 16–18 years old boys. The orienteers had the same percentage type I fibres in vastus lateralis and gastrocnemius as in deltoideus, but higher percentage type I fibres in vastus lateralis compared with the controls. The similarity between trained and untrained muscle in the orienteers suggests that training had not caused the high percentage type I fibres which rather might be the result of selection of individuals with the best prerequisites for high oxidative capacity. However, the distribution of type II subgroups in the leg muscles of the orienteers differed from both their own deltoideus and leg muscles of the controls, the relationship IIA/IIB being altered in favour of the more oxidative IIA. The leg muscles of the orienteers also showed an increased occurrence of the normally rare IIC fibre. These latter findings point at the possibility of a training induced alteration in the subgroup pattern. Unlike in the controls there was no significant difference in succinate dehydrogenase activity, measured in single fibres, between type I and II fibres in gastrocnemius of the orienteers. Thus, type II fibres have the ability metabolically to adapt to high oxidative demands. This might to some extent be mediated by a conversion from IIB to IIA form.
Absence of Restricted Diffusion in Cutaneous Capillaries
Authors: Paaske William P. 
Published: December 2008

AbstractCapillary permeability in cutaneous tissue for57Co‐cyanocobalamin (57Co‐B12) was determined by the single injection, external registration method. The capillary diffusion capacity, CDC (the permeability‐surface area product, PS) was 2.3 ml/100 g·min. Capillary extraction was 0.48 at a plasma flow of 4.1 ml/ 100 g·min. Results were compared to51Cr‐EDTA data from a previous study with identical method and preparation. As CDC(51Cr‐EDTA)/CDC(51Co‐B12) was 1.61 and as D(51Cr‐EDTA)/D(51Co‐B12), the ratio between the free diffusion coefficients in water at 37deg;C, was 1.79 it is concluded that restricted diffusion does not occur in cutaneous tissue for57Co‐B12 as compared to51Cr‐EDTA,i.e.51Cr‐EDTA and57Co‐B12 diffuse across the capillary membrane of cutaneous tissue at rates proportional to their respective free diffusion coefficients in water. The Pappenheimer equivalent pore radius estimate of 30 Å and the Karnovsky interendothelial 40 Å slit width are both defective in explaining the experimental data. The transendothelial patent channel system of fused vesicles (Simionescu, Simionescu and Palade 1975) is a possible structural equivalent for the present findings. The results support the hypothesis that capillaries of continuous type exhibit similar permeation characteristics regardless of the tissue in which they are located.
Responses of Reindeer to Water Loading, Water Restriction and ADH
Authors: Valtonen Maija , Eriksson Lea 
Published: December 2008

AbstractTwo female reindeer were hydrated by administration of (10% of b.wt.) water into the rumen. The diuretic response was very fast and strong but the urea and electrolyte excretion were little affected. Dehydration was carried out by not giving the reindeer water for 48 h. This water deprivation caused a loss of up to 20% of their body weight. The urine osmolality did not exceed 840 mosm/kg H2O, although the plasma osmolality rose from 300 to 346 and 368 mosm/kg H2O respectively. The plasma and urine urea concentrations were elevated during dehydration, while the urine urea excretion did not increase. Urine sodium concentration did not increase. When the urine flow rate, after two days of water deprivation, decreased to half of the original, the urine Na+ concentration, instead of increasing, went down to half of the original. So did the potassium excretion. When ADH was injected intravenously into hydrated animals a dose of 30 mU of ADH was needed to induce antidiuresis or increased excretion of potassium. The resistance to ADH and the low relative thickness of the medulla confirm the limited capacity of reindeer kidney to concentrate urine or to excrete a solute load. On the other hand, reindeer is able rapidly to excrete surplus water without affecting the electrolyte or nitrogen balance.
Suppression of the Excitatory Adrenergic Neurotransmission; a Possible Role of Cholinergic Nerves in the Retractor Penis Muscle
Authors: Klinge Erik , Sjöstrand Nils O. 
Published: December 2008

AbstractThe excitatory adrenergic response to transmural nerve stimulation of the isolated retractor penis (rp) of dog, rat, cat, horse, boar, elk, bull, ram and goat, as well as the evoked release of 3H from dog rp preloaded with 3H‐noradrenaline were studied. In untreated preparations a low concentration of scopolamine could markedly increase the excitatory adrenergic response. On the contrary, physostigmine per se suppressed this response and so did acetylcholine. Scopolamine or atropine totally prevented these suppressions. They also immediately restored the suppressed responses in spite of continuous presence of physostigmine and/or acetylcholine. In the rat rp there was no suppression of the response by physostigmine. Physostigmine decreased the evoked release of 3H and this effect was counteracted by scopolamine. The rp of dog, gelding, boar, hog, bull and ram contained considerable amounts of noradrenaline and also of acetylcholine. It is suggested that one action of cholinergic nerves in the rp is muscarinic suppression of the excitatory adrenergic neurotransmission.
Electrical Activity of the Rat Uterus during Early Pregnancy and Abortion
Authors: Talo A. , Kärki A. E. 
Published: December 2008

AbstractElectrical activity of the rat uterus was recorded for 1 h daily on days 2–9 of pregnancy with 6 electrodes chronically implanted in the left uterine horn. In 10 untreated and 7 ergocornine treated rats, activity decreased in frequency and intensity during the first days of pregnancy. After day 3 activity was present in only about 30 % of electrodes as compared to 85 % on day 2. Abortion was induced by ergocornine injected on day 5. In these rats the frequency of bursts increased on days 8 and 9. During the peak of activity the majority of bursts spread in the cervical direction.
Evidence of Decarboxylation of Lysine by Mammalian Ornithine Decarboxylase
Authors: Persson Lo 
Published: December 2008

AbstractIn enzymic preparations from mouse kidney stimulated with the anabolic steroid Durabolin (nandrolone phenpropionate) lysine and ornithine were shown to inhibit the decarboxylation of each other competitively. The Michaelis constants for the decarboxylations were approximately equal to the inhibition constants of the two amino acids. The pH optima of the decarboxylation of lysine and ornithine were found to be identical. Chromatographic studies of the enzyme preparation on a Sephadex G‐150 Superfine column did not bring about a separation of the two enzyme activities. The ratio of the decarboxylating activities was practically the same during the elution. Lysine decarboxylating activity was also shown to be present in growth hormone stimulated rat liver. The results are in agreement with the assumption that the decarboxylation of lysine and ornithine is carried out by the same enzyme.
In Vitro Studies of Frog Mucous Glands
Authors: Skoglund C. R. , Sjöberg E. 
Published: December 2008

AbstractThe ionic outflow, mainly consisting of Na+ and Cl‐, from the mucous glands in an excised nerve‐skin preparation of frog has been determined by recording the conductance changes occurring in a fluid layer covering a small area of the skin surface. In the main series of experiments the glands were activated by stimulation of sympathetic nerve fibers in the skin nerve. The relationship between the ionic outflow and the number of nerve volleys was studied over a wide range. The outflow per impulse was found to be fairly constant during the first tens of impulses but diminished gradually with increasing number of stimuli up to a certain maximum value—varying in different preparations—after which the outflow ceased completely. During the initial phase of stimulation the outflow is most likely caused by an ejection of preformed secretion due to the contractions of the glandular myoepithelium. The continued outflow in the later stages of the stimulation periods must be due to production of new secretion. Since the glandular epithelium is devoid of nerve terminals a nervous control of the ionic secretion can only be explained by an indirect influence mediated either by transmitter diffusion from the myoepithelial nerve endings or by a close electric coupling between the contractile and the secretory gland cells. Adrenaline and noradrenaline induce ionic outflows which like those evoked by nerve stimulation are inhibited by the β‐adrenoreceptor blocker propranolol, α‐adrenoreceptor blockers being without effect. A serendipitous finding of tonus changes in the frog skin during nerve stimulation is also described.
Capillary Permeability in Skeletal Muscle
Authors: Paaske William P. 
Published: December 2008

AbstractCapillary permeability in skeletal muscle was investigated by applying the single injection, external registration method to the autoperfused cat gastrocnemius preparation.51Cr‐EDTA (MW: 341.2) and57Co‐B12 (MW: 1353.5) served as simultaneously injected indicators. At a plasma flow of 7 ml/100 g×min and an assumed capillary surface area, S, of 70 cma/g the permeability coefficients Pd(51Cr‐EDTA) and Pd(57Co‐B12) were 0.74 × 10‐5cm/s and 0.45×10‐6cm/s, respectively. However, correction for the recruitment of perfused capillaries yields Pd(51C‐EDTA)‐ 1.5 × 10‐5cm/s and Pd(57Co‐B12) = 0.9 × 10‐5cm/s. The results indicate that the permeability of a muscle capillary for hydrophilic solutes is similar to that of continuous capillaries in other tissues. The Pappenheimer pore radius estimate of 30 Å, the Karnovsky 40 Å interendothelial slit width, and pinocytotic transport are defective in accounting for the results as51Cr‐EDTA and57Co‐B12 diffuse across the capillary membrane at rates proportional to their free diffusion coefficients in water (CDC(51Cr‐EDTA)/CDC(57Co‐B12) = D(51Cr‐EDTA)/D(57Co‐B12)= 1.79). The intraendothelial patent channel system of fused vesicles might be the pathway for transcapillary exchange of hydrophilic molecules as this system alone could account for the experimental results. Only 1–2 open channels per μm capillary length are necessary to account for the observed permeabilities. For both indicators CDC was a linear function of plasma flow and CDC increased 3‐3.5 fold when plasma flow increased from 4 to 52 ml/100 g× min. Assuming constant permeability coefficients, the CDC increase with plasma flow reflects an increase in capillary surface area indicating a 3‐3.5 fold recruitment of capillaries. A constant ratio of CDC(51Cr‐EDTA)/CDC(57Co‐B12) within the perfusion range indicates that51Cr‐EDTA and57Co‐B12 can be employed at plasma flow > 4 ml/100 g× min without risk of early back‐diffusion resulting in underestimation of permeability.
Release of Thiamine and Formation of a Methylthiamine‐Like Substance in the Phrenic Nerve‐Diaphragm Preparation of the Rat
Authors: Waldenlind Lennart 
Published: December 2008

AbstractAn increased formation of a radioactive methylthiamine‐like substance (MTLS) in the end plate region of the rat diaphragm muscle and a release of radioactivity chromatographed as thiamine into the bath medium after a subcutaneous injection of35S‐thiamine were found after stimulation of the phrenic nerve. There was also an increased formation of the radioactive methylthiamine‐like substance in the denervated diaphragm preparation incubated with radioactive acetylcholine (ACh) in comparison with the innervated diaphragm.
Plasma Protein Dynamics: Albumin and IgG Capillary Permeability, Extravascular Movement and Regional Blood Flow in Unanesthetized Rabbits
Authors: Bill Anders 
Published: December 2008

AbstractThe turnover rate constants for extravascular albumin and immunoglobulin‐G (IgG) and the turnover rates and extravascular spaces for the proteins and regional blood flow were determined in different tissues in unanesthetized rabbits. The turnover rate constant in percent per minute for extravascular albumin was 1.9 in the kidney cortex and 1.4 in the kidney medulla, about 0.8‐1.4 in the lung, small intestine, choroid plexus and heart muscle and about 0.2‐0.6 in the skeletal muscle, stomach wall and gall bladder. The turnover rate constants for IgG were similar or lower. The plasma equivalent extravascular albumin space was 145 μl/g in the kidney medulla, about 100 μ1/g in the gall bladder, heart muscle, choroid plexus and small intestine, 30–70 μl/g in the kidney cortex, lung, stomach wall and triceps muscle. The extravascular IgG spaces were similar or smaller. In the liver, spleen and adrenals where extravascular spaces could not be determined, the ratios total IgG space/total albumin space were about 1.3‐1.5. Extraction of albumin defined as turnover rate of extravascular albumin/regional plasma flow could not be determined in the liver, spleen and adrenals. It was zero in the brain cortex, about 0.001 % in the lung and around 0.01‐0.05 % in most other tissues. The results suggest that in the walls of the capillaries of the kidney cortex, stomach wall, skeletal muscle and gall bladder there was convection of the proteins with pinocytosis and/or through large pores, diffusion playing little role. The albumin and the IgG passed through the tissues and were drained essentially by bulk flow. In the heart muscle, choroid plexus, lung and small intestine there seemed to be some diffusion of albumin through the capillary wall in addition to convection. Accumulation of IgG in the liver, spleen and adrenals was probably caused by adsorption to cells belonging to the RES.
Influence of Age on Sensitivity and Effector Mechanisms of the Carotid Baroreflex
Authors: Lindblad Lars Erik 
Published: December 2008

AbstractIn 30 healthy subjects aged 20–48 years the hemodynamic response to carotid sinus stimulation (neck suction ‐40 mmHg) was studied. Heart rate, arterial pressure and cardiac output (dye dilution technique) were measured. In order to evaluate the effect of age on carotid sinus function the material was subdivided into two arbitrary subgroups, aged up to 30 years (n = 15) respectively 30 years and above (n = 15). Carotid sinus stimulation induced a significantly greater reduction in mean arterial pressure in the younger group compared to the older group. The heart rate reduction was, on the average, slightly greater in the younger group though the difference was not significant. In both groups a significant decrease in cardiac output contributed to the demonstrated reduction in mean arterial pressure. As the decrease in cardiac output was, on the average, slightly smaller in the younger group, the results indicate that the greater blood pressure response in the younger group was due to a greater reduction in peripheral vascular resistance. This is further supported by the finding of a significant correlation between changes in total peripheral vascular resistance, elicited by carotid sinus stimulation and age.
Choline Acetyltransferase Activity in the Denervated Urinary Bladder of the Rat
Authors: Ekström Jörgen , Elmér Mats 
Published: December 2008

AbstractAfter extirpation of the pelvic ganglia the choline acetyltransferase activity decreased markedly indicating that most of the postganglionic cholinergic neurones of the bladder take this route. A small decrease in the activity of this enzyme was found after section of the hypogastric nerves, showing that these nerves contribute to some extent to the cholinergic innervation. The residual enzyme activity found after a combination of the two surgical procedures suggests that neurones relay distal to the level of the section of the hypogastric nerves and pass outside the pelvic ganglia and (or) that neurones pass the pelvic ganglia and relay distal to them. Electrical stimulation of the hypogastric nerves after extirpation of the pelvic ganglia and the use of blocking drugs showed on the existence of cholinergic neurones passing outside the pelvic ganglia, some of them relaying distal to the point of stimulation.
Capillary Permeability to Albumin in Normotensive and Spontaneously Hypertensive Rats
Authors: Rippe Bengt , Folkow Björn 
Published: December 2008

AbstractTranscapillary passage of plasma proteins is enhanced in man's primary hypertension and it is debated whether this reflects increased permeability or merely a raised capillary pressure. To elucidate this problem, maximally vasodilated hindquarters of spontaneously hypertensive rats (SHR) and normotensive controls (NCR) were perfused in parallel at constant flow with dextran, horse serum or mixtures of the two, using labelled albumin as indicator of capillary permeability to macromolecules. By equal increases of venous pressure modest filtration was maintained during one hour, after which the edema and its albumin content were determined. — There was less edema in SHR, reflecting a slightly lower postcapillary resistance and a much higher precapillary resistance compared with NCR, which here resulted in a lower capillary pressure in SHR. In both SHR and NCR the presence of dextran slightly enhanced the capillary filtration coefficient but increased albumin permeability up to tenfold, also after antihistamine drugs. However, for each perfusate the SHR capillaries were, if anything, slightly less permeable to albumin than the NCR ones. — The results suggest that the enhanced transcapillary passage of plasma proteins in primary hypertension reflects an increased capillary pressure in some circuit(s), probably mainly skeletal muscle, resulting from the functional balance in vivo between the pre‐ and postcapillary resistances.