| 1. |
- Elcadi, Guilherme H., 1966-, et al.
(författare)
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Shoulder and forearm oxygenation and myoelectric activity in patients with work related muscle pain and healthy subjects
- 2013
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Ingår i: European Journal of Applied Physiology. - New York : Springer. - 1439-6319 .- 1439-6327. ; 113:5, s. 1103-1115
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Tidskriftsartikel (refereegranskat)abstract
- We tested hypotheses of (i) reduced oxygen usage, oxygen recovery, blood flow and oxygen consumption; and (ii) increased muscle activity for patients diagnosed with work related muscle pain in comparison to healthy controls. Oxygenation was measured with near infrared spectroscopy (NIRS), and muscle activity with EMG for the extensor carpi radialis (ECR) and trapezius descendens (TD) muscles. Eighteen patients with diffuse neck-shoulder-arm pain and seventeen controls (matched in age and sex) were equipped with NIRS and EMG probes. After determining an individual’s maximum voluntary contraction (MVC) force, short term (20 sec) isometric contractions for the ECR and TD of 10%, 30%, 50% and 70% MVC generated ∆StO2% and StO2% recovery (Rslope) from NIRS, and RMS%max from EMG signals. In addition, upper arm venous (VO) and arterial (AO) occlusions generated slopes of total hemoglobin (HbTslope) and deoxyhemoglobin (HHbslope) for the resting ECR as surrogates of blood flow and oxygen consumption, respectively. Mixed Model analyses, t-tests, and Mann-Whitney test were used to assess differences between groups. There was no significant difference in MVC between groups for either muscle. Also, ∆StO2%, Rslope for either muscle, and ECR-HbTslope were not different between groups, thus our hypotheses of reduced oxygen use, recovery, and blood flow for patients were not confirmed. However, patients had a significantly lower ECR-HHbslope confirming our hypothesis of reduced consumption. Further, there was no difference in RMS%max during contractions meaning that the hypothesis of increased activity for patients was not confirmed. When taking into account the number of NIRS variables studied, differences we found between our patient group and healthy controls (i.e. in forearm oxygen consumption and shoulder oxygen saturation level) may be considered modest. Overall our findings may have been impacted by the fact that our patients and controls were similar in muscle strength, which is in contrast to previous studies.
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| 2. |
- Eriksson, Anders, et al.
(författare)
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Skeletal muscle morphology in power-lifters with and without anabolic steroids
- 2005
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 124:2, s. 167-175
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Tidskriftsartikel (refereegranskat)abstract
- The morphological appearance of the vastus lateralis (VL) muscle from high-level power-lifters on long-term anabolic steroid supplementation (PAS) and power-lifters never taking anabolic steroids (P) was compared. The effects of long- and short-term supplementation were compared. Enzyme-immunohistochemical investigations were performed to assess muscle fiber type composition, fiber area, number of myonuclei per fiber, internal myonuclei, myonuclear domains and proportion of satellite cells. The PAS group had larger type I, IIA, IIAB and IIC fiber areas (p<0.05). The number of myonuclei/fiber and the proportion of central nuclei were significantly higher in the PAS group (p<0.05). Similar results were seen in the trapezius muscle (T) but additionally, in T the proportion of fibers expressing developmental myosin isoforms was higher in the PAS group compared to the P group. Further, in VL, the PAS group had significantly larger nuclear domains in fibers containing > or = 5 myonuclei. The results of AS on VL morphology in this study were similar to previously reported short-term effects of AS on VL. The initial effects from AS appear to be maintained for several years.
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| 3. |
- Huttunen, Piritta, et al.
(författare)
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Leaf trichome production and responses to defoliation and drought in Arabidopsis lyrata (Brassicaceae)
- 2010
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Ingår i: Annales Botanici Fennici. - Helsinki : Finnish Zoological and Botanical Publishing Board. - 0003-3847 .- 1797-2442. ; 47:3, s. 199-207
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Tidskriftsartikel (refereegranskat)abstract
- Leaf trichomes can protect plants against herbivory and drought, but can be costly to produce. Theory suggests that selection for reduced costs of resistance may result in the evolution of inducible defences. We quantified variation in tolerance to drought and defoliation, and tested the hypotheses that (a) tolerance is associated with cost, (b) leaf trichome production increases tolerance to drought, and (c) trichome production is increased in response to defoliation and drought stress in Arabidopsis lyrata (Brassicaceae). Eight maternal half-sib families were exposed to two watering regimes and four defoliation treatments in a factorial design. Tolerance to drought varied among families and was inversely related to leaf size, but was not related to trichome density. Family mean performance in the low-watering treatment tended to correlate negatively with that in the control treatment. Trichome production was not induced by defoliation or drought stress. The results suggest that there is genetic variation in tolerance to drought in the study population, that tolerance to drought is associated with a cost, and that trichome production does not increase tolerance to drought in A. lyrata.
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| 4. |
- Hadrévi, Jenny, 1977-, et al.
(författare)
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Comparative metabolomics of muscle interstitium fluid in human trapezius myalgia: an in vivo microdialysis study
- 2013
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Ingår i: European Journal of Applied Physiology. - : Springer Verlag (Germany). - 1439-6319 .- 1439-6327. ; 113:12, s. 2977-2989
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms behind trapezius myalgia are unclear. Many hypotheses have been presented suggesting an altered metabolism in the muscle. Here, muscle microdialysate from healthy and myalgic muscle is analysed using metabolomics. Metabolomics analyse a vast number of metabolites, enabling a comprehensive explorative screening of the cellular processes in the muscle. less thanbrgreater than less thanbrgreater thanMicrodialysate samples were obtained from the shoulder muscle of healthy and myalgic subjects that performed a work and stress test. Samples from the baseline period and from the recovery period were analysed using gas chromatography-mass spectrometry (GC-MS) together with multivariate analysis to detect differences in extracellular content of metabolites between groups. Systematic differences in metabolites between groups were identified using multivariate analysis and orthogonal partial least square discriminate analysis (OPLS-DA). A complementary Mann-Whitney U test of group difference in individual metabolites was also performed. less thanbrgreater than less thanbrgreater thanA large number of metabolites were detected and identified in this screening study. At baseline, no systematic differences between groups were observed according to the OPLS-DA. However, two metabolites, l-leucine and pyroglutamic acid, were significantly more abundant in the myalgic muscle compared to the healthy muscle. In the recovery period, systematic difference in metabolites between the groups was observed according to the OPLS-DA. The groups differed in amino acids, fatty acids and carbohydrates. Myristic acid and putrescine were significantly more abundant and beta-d-glucopyranose was significantly less abundant in the myalgic muscle. less thanbrgreater than less thanbrgreater thanThis study provides important information regarding the metabolite content, thereby presenting new clues regarding the pathophysiology of the myalgic muscle.
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| 5. |
- Flodgren, Gerd, 1961-, et al.
(författare)
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Changes in interstitial noradrenaline, trapezius muscle activity and oxygen saturation during low-load work and recovery
- 2009
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 107:1, s. 31-42
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Tidskriftsartikel (refereegranskat)abstract
- Both physical as well as mental demands result in an increased activity in the sympathetic nervous system (SNS) with changes in blood-pressure and heart-rate. Through local release of catecholamines, e.g. noradrenaline (NAd) SNS exerts various actions at the muscle level. The aims of this study were to investigate the effects of low-load repetitive work alone and in combination with mental demands on local muscle interstitial noradrenaline concentration [NAd]i, muscle activity and oxygenation, assessed with microdialysis, surface electromyography, and near-infrared spectroscopy, respectively. Healthy females (n = 15) were exposed to (1) 30 min repetitive work (RW) and (2) 30 min repetitive work with superimposed mental load (RWML) on two different occasions. Muscle [NAd]i and muscle activity increased significantly in response to RW, but did not increase further during RWML. For RW, [NAd]i was found to be inversely correlated to muscle activity. Oxygenation decreased significantly during work, independently of occasion. Our findings indicate that low-load work causes significantly increased trapezius muscle [NAd]i in healthy females, and short periods of superimposed mental load do not add to this increase and further, that both muscle activity and oxygenation were unaffected by the superimposed mental load.
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| 6. |
- Samsioe, Annika, et al.
(författare)
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Intrauterine death, fetal malformation, and delayed pregnancy in Ljungan virus-infected mice
- 2006
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Ingår i: Birth defects research. Part B. Developmental and reproductice toxicology. - : Wiley. - 1542-9733 .- 1542-9741. ; 77:4, s. 251-256
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A picornavirus (Ljunganvirus [LV]) has recently been associated with disease during pregnancy in its natural rodent reservoir and in humans. A study of laboratory mice infected under controlled conditions was therefore undertaken. METHODS: CD-1 female mice were infected gestational day two and subjected to varying regimes of stress. RESULTS: LV infection in combination with stress resulted in uterine resorptions, malformations, and neonatal death. A short delay in time to first pregnancy and births was observed in pairs infected in utero. CONCLUSIONS: LV is found in different species of native animals in both Europe and the United States and human epidemiological evidence connects LV and human reproduction, while the observations here indicate that LV is responsible for reproductive problems in a laboratory mouse model. The current findings suggest that the hypothesis that LV also causes disease in pregnant women and their offspring deserves further study.
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| 7. |
- Hadrévi, Jenny, 1977-, et al.
(författare)
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Multivariate Modeling of Proteins Related to Trapezius Myalgia, a Comparative Study of Female Cleaners with or without Pain
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:9, s. e73285-
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Tidskriftsartikel (refereegranskat)abstract
- The prevalence of chronic trapezius myalgia is high in women with high exposure to awkward working positions, repetitive movements and movements with high precision demands. The mechanisms behind chronic trapezius myalgia are not fully understood. The purpose of this study was to explore the differences in protein content between healthy and myalgic trapezius muscle using proteomics. Muscle biopsies from 12 female cleaners with work-related trapezius myalgia and 12 pain free female cleaners were obtained from the descending part of the trapezius. Proteins were separated with two-dimensional differential gel electrophoresis (2D-DIGE) and selected proteins were identified with mass spectrometry. In order to discriminate the two groups, quantified proteins were fitted to a multivariate analysis: partial least square discriminate analysis. The model separated 28 unique proteins which were related to glycolysis, the tricaboxylic acid cycle, to the contractile apparatus, the cytoskeleton and to acute response proteins. The results suggest altered metabolism, a higher abundance of proteins related to inflammation in myalgic cleaners compared to healthy, and a possible alteration of the contractile apparatus. This explorative proteomic screening of proteins related to chronic pain in the trapezius muscle provides new important aspects of the pathophysiology behind chronic trapezius myalgia.
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| 8. |
- Sandberg, Camilla, et al.
(författare)
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Slower Skeletal Muscle Oxygenation Kinetics in Adults With Complex Congenital Heart Disease
- 2019
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Ingår i: Canadian Journal of Cardiology. - : Elsevier. - 0828-282X .- 1916-7075. ; 35:12, s. 1815-1823
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Tidskriftsartikel (refereegranskat)abstract
- Background: Adults with complex congenital heart disease (CHD) show reduced aerobic exercise capacity and impaired skeletal muscle function compared with healthy peers. Peripheral muscle factors are presumed to be important contributors to the aerobic capacity, but the mechanisms are poorly understood. The aim of the present study was to investigate differences between adults with CHD and controls in muscle oxygenation kinetics at rest, and during and after exercise.Methods: Seventy-four patients with complex CHD (mean age 35.6 ± 14.3 years, female n = 22) were recruited. Seventy-four age- and sex-matched subjects were recruited as controls. Muscle oxygenation was successfully determined on the anterior portion of the deltoid muscle using near-infrared spectroscopy in 65 patients and 71 controls. Measurements were made at rest, during isotonic shoulder flexions (0-90°) to exhaustion, and during recovery.Results: The patients with CHD performed fewer shoulder flexions (40 ± 17 vs 69 ± 40; P < 0.001), had lower muscle oxygen saturation (StO2) at rest (58 ± 18% vs 69 ± 18%; P < 0.001), slower desaturation rate at exercise onset (−9.7 ± 5.9 vs −15.1 ± 6.5% StO2 × 3.5 s−1, P <0.001), and slower resaturation rate post exercise (4.0 ± 2.7 vs 5.4 ± 3.6% StO2 × 3.5 s−1; P = 0.009) compared with the controls. Conclusions: In comparison with age- and sex-matched controls, adults with complex CHD had slower oxygenation kinetics. This altered skeletal muscle metabolism might contribute to the impaired skeletal muscle endurance capacity shown and thereby also to the reduced aerobic capacity in this population.
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| 9. |
- Wiesinger, Birgitta, et al.
(författare)
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Jaw-opening accuracy is not affected by masseter muscle vibration in healthy men
- 2014
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Ingår i: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 232:11, s. 3501-3508
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Tidskriftsartikel (refereegranskat)abstract
- There is a functional integration between the jaw and neck regions with head extension–flexion movements during jaw-opening/closing tasks. We recently reported that trigeminal nociceptive input by injection of hypertonic saline into the masseter muscle altered this integrated jaw–neck function during jaw-opening/closing tasks. Thus, in jaw-opening to a predefined position, the head–neck component increased during pain. Previous studies have indicated that muscle spindle stimulation by vibration of the masseter muscle may influence jaw movement amplitudes, but the possible effect on the integrated jaw–neck function is unknown. The aim of this study was to investigate the effect of masseter muscle vibration on jaw–head movements during a continuous jaw-opening/closing task to a target position. Sixteen healthy men performed two trials without vibration (Control) and two trials with bilateral masseter muscle vibration (Vibration). Movements of the mandible and the head were registered with a wireless three-dimensional optoelectronic recording system. Differences in jaw-opening and head movement amplitudes between Control and Vibration, as well as achievement of the predefined jaw-opening target position, were analysed with Wilcoxon’s matched pairs test. No significant group effects from vibration were found for jaw or head movement amplitudes, or in the achievement of the target jaw-opening position. A covariation between the jaw and head movement amplitudes was observed. The results imply a high stability for the jaw motor system in a target jaw-opening task and that this task was achieved with the head–neck and jaw working as an integrated system.
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| 10. |
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