| 1. |
|
|
| 2. |
|
|
| 3. |
- Lahti, A-M, 1959, et al.
(författare)
-
Effect of alpha-trinositol on secretion induced by Escherichia coli ST-toxin in rat jejunum.
- 2003
-
Ingår i: Acta physiologica Scandinavica. - : Wiley. - 0001-6772. ; 179:4, s. 373-9
-
Tidskriftsartikel (refereegranskat)abstract
- d-myo-inositol-1,2,6-trisphosphate (alpha-trinositol, PP56), is a synthetic isomer of the intracellular second messenger, d-myo-inositol-1,4,5-trisphospahate. The pharmacological actions of alpha-trinositol include potent anti-inflammatory properties and inhibition of the secretion induced by cholera toxin and obstructive ileus. In the present study, we investigated whether alpha-trinositol was able to influence the secretion induced by heat-stable ST-toxin from Escherichia coli in the rat jejunum.
|
|
| 4. |
- Malm, Christer, et al.
(författare)
-
Immune system alteration in response to two consecutive soccer games.
- 2004
-
Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 180:2, s. 143-55
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: Changes in leucocyte and monocyte subpopulations were investigated in 10 elite male soccer players aged 16-19 years. The purpose was to perform a descriptive study of immunological alterations in elite soccer players in response to two consecutive games separated by 20 h. It was hypothesized that in response to two games the players would show signs of short-term immunosuppression. METHODS: Blood samples were taken before the first soccer game, immediately after the second game and after 6, 24, 48 and 72 h. Cell surface antigens, testosterone and cortisol were investigated. RESULTS: During the first 6 h after the second game there was a significant increase in number of circulating neutrophils, mature (CD20+ CD5+) B cells and CD4/CD8 ratio. A significant decrease was observed in the number of natural killer (NK) cells, monocytes and adhesion on lymphocytes and monocytes. In a delayed phase, 48 h after the second game the expression of both adhesion and signalling molecules increased on lymphocytes and monocytes. Changes in adhesion and signalling molecules at 48 h correlated negatively to the subjects VO2max, suggesting larger immunological response to similar exercise in subjects with lower aerobic exercise capacity. CONCLUSION: In response to competitive soccer exercise some immunological variables are enhanced while others are depressed. Observed changes may serve a purpose in adaptation to exercise by signalling via adhesion.
|
|
| 5. |
|
|
| 6. |
- Tesch, Per A, et al.
(författare)
-
Muscle hypertrophy following five wk resistance training a non-gravity dependent loading principle
- 2004
-
Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 1748-1708 .- 0001-6772 .- 1365-201X. ; 180:1, s. 89-98
-
Tidskriftsartikel (refereegranskat)abstract
- The efficacy of a mechanical, gravity-independent resistance exercise (RE) system to induce strength gains and muscle hypertrophy was validated. Designed for space crew in orbit, this technique offers resistance during coupled concentric and eccentric actions by utilizing the inertia of a rotating flywheel(s), set in motion by the trainee. Methods: Ten middle-aged (30–53 years) men and women performed four sets of seven maximal, unilateral (left limb) knee extensions two or three times weekly for 5 weeks. Knee extensor force and electromyographic (EMG) activity of the three superficial quadriceps muscles were measured before and after this intervention. In addition, with the use of magnetic resonance imaging (MRI), volume of individual knee extensor and ankle plantar flexor muscles was assessed. Results: Over the 12 training sessions, the average concentric (CON) and eccentric (ECC) force generated during exercise increased by 11% (P < 0.05). Likewise, maximal isometric strength (maximal voluntary contraction, MVC) at 90 and 120 knee angle increased by (P < 0.05) 11 and 12% respectively, after training. Neither individual quadriceps muscle showed a change (P > 0.05) in maximal integrated EMG (iEMG) activity. Quadriceps muscle volume increased by 6.1% (P < 0.05). Although the magnitude of response varied, all individual quadriceps muscles showed increased (P < 0.05) volume after training. As expected, ankle plantar flexor volume of the trained limb was unchanged (P > 0.05). Likewise, MVC, CON and ECC force, iEMG and knee extensor and plantar flexor muscle volume were unaltered (P > 0.05) in the right, non-trained limb. Conclusion: The results of this study show that the present RE regimen produces marked muscle hypertrophy and important increases in maximal voluntary strength and appears equally effective as RE paradigms using gravity-dependent weights, in this regard. Keywords concentric and eccentric muscle actions, exercise countermeasures, flywheel technology, muscle strength and volume, spaceflight.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Zhang, Qiuxia, 1960, et al.
(författare)
-
Muscle blood flow in response to concentric muscular activity vs passive venous compression
- 2004
-
Ingår i: Acta Physiol Scand. - : Wiley. - 0001-6772 .- 1365-201X. ; 180:1, s. 57-62
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: To measure muscle blood flow (MBF) using photoplethysmography (PPG) following concentric muscular activity of the leg (active treatment) or passive venous compression (passive treatment) with or without venous obstruction. METHODS: In study A, blood flow in the anterior tibial muscle was measured in 15 healthy subjects with a mean age of 30 years. In study B, blood flow in the gastrocnemius muscle was measured in nine healthy subjects with a mean age of 34 years. Subjects performed concentric muscular activity in one leg. Passive venous compression by a venous foot pump was applied in the contralateral leg. RESULTS: MBF increased significantly following concentric muscular activity, but not following passive venous compression. MBF decreased in both legs when venous obstruction, induced by a thigh tourniquet, was applied. However, MBF was significantly higher following concentric muscular activity than passive venous compression. CONCLUSION: We conclude that concentric muscular activity produces higher MBF values than passive venous compression.
|
|
| 10. |
- Abdul-Rahman, A, et al.
(författare)
-
Local cerebral blood flow in the rat during severe hypoglycemia, and in the recovery period following glucose injection
- 1980
-
Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 109:3, s. 307-314
-
Tidskriftsartikel (refereegranskat)abstract
- In order to assess the influence of severe hypoglycemia on local cerebral blood flow (1-CBF) artificially ventilated rats, maintained on 70% N2O, were injected with insulin to provide either an EEG pattern of slow-wave polyspikes, or cessation of spontaneous EEG activity for 5, 15 or 30 min ("coma"). In other animals, glucose was injected at the end of a 30 min period of "coma" and 1-CBF was measured after recovery periods of 5, 30, 90, or 180 min. Local CBF was measured autoradiographically with 14C-iodoantipyrine as the diffusible tracer. In the slow-wave polyspike period 1-CBF was increased in most of the structures studied, and reached values that were 1.4 to 3.2 times greater than control. In many structures, cessation of EEG activity was accompanied by a further increase in 1-CBF, with some structures (thalamus, hypothalamus, pontine gray, and cerebellar cortex) showing flow rates of 400--500% of control. The increase in 1-CBF was unrelated to arterial hypertension, hypercapnia, or hypoxia. 5 min after glucose injection the hyperemia persisted in only some of the structures studied; in others, the 1-CBF were close to, or below, control values. During the subsequent recovery period 1-CBF was markedly reduced with some structures (cerebral cortical areas, hippocampus, and caudate-putamen) showing flow rates of only 20--35% of control. In others, notably pontine gray and cerebellar cortex, secondary hypoperfusion was never observed. The hypoperfusion was unrelated to arterial hypertension, hypocapnia, or increase in intracranial pressure. It is concluded that, like hypoxia and ischemia, substrate deficiency due to hypoglycemia is accompanied by vasodilatation in the brain. Furthermore, like long-lasting ischemia, severe hypoglycemia is followed by a delayed hypoperfusion syndrome that, by restricting oxygen supply, may well contribute to the final cell damage incurred.
|
|
| 11. |
- Abletshauser, C, et al.
(författare)
-
Biosensing of arteriosclerotic nanoplaque formation and interaction with an HMG-CoA reductase inhibitor
- 2002
-
Ingår i: Acta Physiologica Scandinavica. - 0001-6772 .- 1365-201X. ; 176, s. 131-146
-
Tidskriftsartikel (refereegranskat)abstract
- Proteoheparan sulphate can be adsorbed to a methylated silica surface in a monomolecular layer via its transmembrane hydrophobic protein core domain. As a result of electrostatic repulsion, its anionic glycosaminoglycan side chains are stretched out into the blood substitute solution, thereby representing one receptor site for specific lipoprotein binding through basic amino acid-rich residues within their apolipoproteins. The binding process was studied by ellipsometric techniques suggesting that high-density lipoprotein (HDL) has a high binding affinity and a protective effect on interfacial heparan sulphate proteoglycan layers with respect to low-density lipoprotein (LDL) and Ca2+ complexation. Low-density lipoprotein was found to deposit strongly at the proteoheparan sulphate-coated surface, particularly in the presence of Ca2+, apparently through complex formation 'proteoglycan-LDL-calcium'. This ternary complex build-up may be interpreted as arteriosclerotic nanoplaque formation on the molecular level responsible for the arteriosclerotic primary lesion. On the other hand, HDL bound to heparan sulphate proteoglycan protected against LDL deposition and completely suppressed calcification of the proteoglycan-lipoprotein complex. In addition, HDL was able to decelerate the ternary complex deposition. Therefore, HDL attached to its proteoglycan receptor sites is thought to raise a multidomain barrier, selection and control motif for transmembrane and paracellular lipoprotein uptake into the arterial wall. Although much remains unclear regarding the mechanism of lipoprotein depositions at proteoglycan-coated surfaces, it seems clear that the use of such systems offers possibilities for investigating lipoprotein deposition at a 'nanoscopic' level under close to physiological conditions. In particular, Ca2+-promoted LDL deposition and the protective effect of HDL even at high Ca2+ and LDL concentrations agree well with previous clinical observations regarding risk and beneficial factors for early stages of atherosclerosis. Considering this, the system was tested on its reliability in a biosensor application in order to unveil possible acute pleiotropic effects of the lipid lowering drug fluvastatin. The very low-density lipoprotein (VLDL)/intermediate-density lipoprotein (IDL)/LDL plasma fraction from a high risk patient with dyslipoproteinaemia and type 2 diabetes mellitus showed beginning arteriosclerotic nanoplaque formation already at a normal blood Ca2+ concentration, with a strong increase at higher Ca2+ concentrations. Fluvastatin, whether applied to the patient (one single 80 mg slow release matrix tablet) or acutely in the experiment (2.2 μmol L-1), markedly slowed down this process of ternary aggregational nanoplaque complexation at all Ca2+ concentrations used. This action resulted without any significant change in lipid concentrations of the patient. Furthermore, after ternary complex build-up, fluvastatin, similar to HDL, was able to reduce nanoplaque adsorption and size. These immediate effects of fluvastatin have to be taken into consideration while interpreting the clinical outcome of long-term studies.
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
- Al-Khalili, L, et al.
(författare)
-
Human skeletal muscle cell differentiation is associated with changes in myogenic markers and enhanced insulin-mediated MAPK and PKB phosphorylation
- 2004
-
Ingår i: Acta Physiologica Scandinavica. - : Wiley-Blackwell. - 0001-6772 .- 1365-201X. ; 180:4, s. 395-403
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: We hypothesized that myogenic differentiation of HSMC would yield a more insulin responsive phenotype.METHODS: We assessed expression of several proteins involved in insulin action or myogenesis during differentiation of primary human skeletal muscle cultures (HSMC).RESULTS: Differentiation increased creatine kinase activity and expression of desmin and myocyte enhancer factor (MEF)2C. No change in expression was observed for big mitogen-activated protein kinase (BMK1/ERK5), MEF2A, insulin receptor (IR), hexokinase II, and IR substrates 1 and 2, while expression of glycogen synthase, extracellular signal-regulated kinase 1 and 2 (ERK1/2 MAP kinase) and the insulin responsive aminopeptidase increased after differentiation. In contrast to protein kinase B (PKB)a, expression of (PKB)b increased, with differentiation. Both basal and insulin-stimulated PI 3-kinase activity increased with differentiation. Insulin-mediated phosphorylation of PKB and ERK1/2 MAP kinase increased after differentiation.CONCLUSION: Components of the insulin-signalling machinery are expressed in myoblast and myotube HSMC; however, insulin responsiveness to PKB and ERK MAP kinase phosphorylation increases with differentiation.
|
|
| 16. |
|
|
| 17. |
- Alkner, Björn, et al.
(författare)
-
Efficacy of a gravity-independent resistance exercise device as a countermeasure to muscle atrophy during 29-day bed rest.
- 2004
-
Ingår i: Acta Physioloogica Scandinavica. - 0001-6772. ; 181:3, s. 345-357
-
Tidskriftsartikel (refereegranskat)abstract
- This study determined changes in knee extensor and plantar flexor muscle volume during 29 days of bed rest with or without resistance exercise using a gravity-independent flywheel ergometer. METHODS: Seventeen men (26-41 years) were subjected to 29 days of bed rest with (n = 8) or without (n = 9) resistance exercise; Supine Squat (SS) and Calf Press (CP) performed every third day. Quadriceps and triceps surae muscle volume was determined before and after bed rest and force and power were measured during training. Prior to these interventions, reproducibility of this device for training and testing was assessed in 23 subjects who performed bilateral maximal concentric, eccentric and isometric (MVC) knee extensions and plantar flexions over repeated sessions with simultaneous measurements of force, power and electromyographic (EMG) activity. RESULTS: Quadriceps and triceps surae muscle volume decreased (P < 0.05) 10 and 16%, respectively, after 29 days bed rest. Exercise maintained quadriceps volume and mitigated triceps surae atrophy. Thus, either muscle showed different response across subject groups (P < 0.05). Force and power output during training were either maintained (P > 0.05) or increased (P < 0.05). EMG amplitude in the training mode was similar (SS; P > 0.05) or greater (CP; P < 0.05) compared with that elicited during MVC. Peak force and power test-retest coefficient of variation (CV) ranged 5-6% and 7-8% for SS and CP, respectively. CONCLUSION: The present data suggest that this resistance exercise paradigm counteracts quadriceps and abates the more substantial triceps surae muscle atrophy in bedridden subjects, and therefore should be an important asset to space travellers.
|
|
| 18. |
|
|
| 19. |
- ANDERSSON, B, et al.
(författare)
-
Angiotensin and the brain
- 1995
-
Ingår i: Acta physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 155:2, s. 117-125
-
Tidskriftsartikel (refereegranskat)
|
|
| 20. |
|
|
| 21. |
- Andersson, Eva A, et al.
(författare)
-
Intramuscular EMG from the hip flexor muscles during human locomotion.
- 1997
-
Ingår i: Acta Physiologica Scandinavica. - 0001-6772 .- 1365-201X. ; 161:3, s. 361-70
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose was to investigate the activation pattern of five major hip flexor muscles and its adaptation to changing speed and mode of progression. A total of 11 healthy subjects performed walking and running on a motor-driven treadmill at speeds ranging from 1.0 to 6.0 m s-1. Intramuscular fine-wire electrodes were used to record myoelectric signals from the iliacus, psoas, sartorius, rectus femoris and tensor fascia latae muscles. The basic pattern, with respect to number of activation periods, remained the same irrespective of speed and mode of progression. However, differences in the relative duration and timing of onset of activation occurred between individual muscles. Over the speed range in walking, a progressively earlier onset was generally seen for the activation period related to hip flexion. Changes in EMG amplitude were measured in the iliacus and psoas muscles and showed a marked increase and difference between walking and running at speeds above 2.0 m s-1. Thus, the alternating flexion-extension movements at the hip during locomotion appear to be governed by a rather fixed 'neural program' which normally only needs minor modulations to accomplish the adjustments accompanying an increase in speed of progression as well as a change from walking to running.
|
|
| 22. |
- Andersson, Irene, 1978, et al.
(författare)
-
Reduced sympathetic responsiveness as well as plasma and tissue noradrenaline concentration in growth hormone transgenic mice
- 2004
-
Ingår i: Acta Physiol Scand. - 0001-6772. ; 182:4, s. 369-78
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: Acromegaly [overproduction of growth hormone (GH)] and GH deficiency have both been associated with alterations in autonomic nervous system function. The aim of this study was to investigate autonomic nervous system influence on heart rate (HR) in transgenic mice overexpressing bovine GH (bGH). METHODS: HR and HR variability (HRV) were measured in conscious young (8-13 weeks) and old (5-6 months) female bGH and control mice using telemetry. HR control was studied using antagonists and an agonist of adrenergic and muscarinic receptors. Noradrenaline was measured in plasma, heart and kidney using high performance liquid chromatography. RESULTS: Average 24 h resting HR did not differ between bGH and control mice. After saline injection and after muscarinic blockade with methylscopolamine HR increase was blunted (in old) or absent (in young) bGH mice compared with control mice (P < 0.05). Phenylephrine caused a baroreflex mediated decrease in HR from around 550 to 300-350 beats min(-1), not different between bGH and control mice. Time- and frequency-domain measures of HRV were reduced in old bGH compared with control mice (P < 0.05). Noradrenaline concentrations were reduced by 25-49% in plasma and tissue of bGH compared with control mice (P < 0.05). CONCLUSION: The current study suggests reduced autonomic modulation of HR in bGH transgenic mice. Thus, GH appears to have marked effects on autonomic tone, reducing sympathetic nervous system function possibly via reduced noradrenaline stores.
|
|
| 23. |
|
|
| 24. |
- Andersson, R. M., et al.
(författare)
-
Modulation of Na+,K+-ATPase activity is of importance for RVD
- 2004
-
Ingår i: Acta Physiologica Scandinavica. - 0001-6772 .- 1365-201X. ; 180:4, s. 329-334
-
Tidskriftsartikel (refereegranskat)abstract
- Aim: This study was performed to examine the role of Na+,K+-ATPase activity for the adaptive response to cell swelling induced by hypoosmoticity, i.e. the regulatory volume decrease (RVD). Methods: The studies were performed on COS-7 cells transfected with rat Na+,K+-ATPase. To study changes in cell volume, cells were loaded with the fluorescent dye calcein and the intensity of the dye, following exposure to a hypoosmotic medium, was recorded with confocal microscopy. Results: Ouabain-mediated inhibition of Na+,K+-ATPase resulted in a dose dependent decrease in the rate of RVD. Total Rb-86(+) uptake as well as ouabain dependent Rb-86(+) uptake, used as an index of Na+,K+-ATPase dependent K+ uptake, was significantly increased during the first 2 min following exposure to hypoosmoticity. Since protein kinase C (PKC) plays an important role in the modulation of RVD, a study was carried out on COS-7 cells expressing rat Na+,K+-ATPase, where Ser23 in the catalytic alpha1 subunit of rat Na+,K+-ATPase had been mutated to Ala (S23A), abolishing a known PKC phosphorylation site. Cells expressing S23A rat Na+,K+-ATPase exhibited a significantly lower rate of RVD and showed no increase in Rb-86(+) uptake during RVD. Conclusion: Taken together, these results suggest that a PKC-mediated transient increase in Na+,K+-ATPase activity plays an important role in RVD.
|
|
| 25. |
- Andersson, Sven
(författare)
-
Cardiovascular responses to intravenous calcitonin gene-related peptide (CGRP) in the albino rabbit
- 1989
-
Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 137:2, s. 279-290
-
Tidskriftsartikel (refereegranskat)abstract
- The regional sensitivity of different vascular beds to i.v. CGRP was investigated in the albino rabbit by using the microsphere method. Experiments were performed without pre-treatment on both conscious and pentobarbital-anaesthetized animals. In addition, in one series on conscious animals, rabbits were pre-treated with indomethacin in order to reduce the formation of prostaglandins. In another series, anaesthetized rabbits were subjected to ganglionic blockade with hexamethonium bromide in order to abolish reflexes involving the autonomic nervous system. 120 pmol kg-1 of CGRP was given to all the animals, the conscious animals receiving the peptide in one infusion lasting 4 min. In the anaesthetized animals, the dose was divided into first a 5-min infusion of 30 pmol kg-1 followed some minutes later by a 3-min infusion of 90 pmol kg-1. The most pronounced vasodilatory effects were seen in the pancreas, gallbladder, stomach, duodenum, tongue, teeth and the conjunctiva/nictitating membrane. In some series marked effects were also seen in the dura mater, choroid plexus and some parts of the brain. In the anaesthetized animals almost no statistically significant effects on local blood flows were seen following the first, smaller, dose, but following the larger dose more pronounced effects were observed. Pre-treatment with indomethacin did not to any great extent affect the responses, which contradicts the involvement of prostaglandins. The pattern of the responses was unaffected by the ganglionic blockade, but the variability of response was reduced. In conclusion there are great regional variations in the sensitivity to circulating CGRP. The patterns shows a resemblance to that obtained in other species, but there are some marked differences, The tissues most susceptible to the peptide are those easily exposed to noxious stimuli and containing CGRP in the sensory nerve endings, observations in agreement with the proposed role for the peptide in neurogenic defence mechanisms.
|
|
