| 1. |
- Larsson, Britt, et al.
(författare)
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Blood supply and oxidative metabolism in muscle biopsies of female cleaners with and without myalgia
- 2004
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Ingår i: The Clinical Journal of Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0749-8047 .- 1536-5409. ; 20:6, s. 440-446
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Pathomechanisms of work-related myalgia are poorly understood. Myalgia is thought to be caused by excitation of nociceptors present in the muscular tissue but not in the muscle fiber itself. Muscle contraction in combination with hypoxia is known to excite nociceptors. Morphologic analysis can contribute to the knowledge of the excitation of nociceptors. This study thoroughly examines the morphology of the trapezius muscle's capillary supply and signs of disturbed oxidative metabolism to understand their role in work-related myalgia. METHODS: Surgical trapezius muscle biopsies were obtained from 25 female cleaners with long-standing work-related myalgia, 25 female cleaners without trapezius myalgia, and 21 healthy teachers. Enzyme and immunohistochemical stainings were performed to highlight fibers with aberrant intermyofibrillar patterns, indicating a disturbed oxidative metabolism (also known as moth-eaten fibers) and a disturbed capillary supply of different fibers. RESULTS: A significantly lower number of capillaries per fiber area in cleaners suffering from myalgia compared with cleaners without trapezius myalgia was found. Moth-eaten fibers were found in the 3 groups, but these fibers were significantly more prevalent in the groups of cleaners than in the healthy teacher group. CONCLUSION: This work indicates that the capillary supply of trapezius is affected in work-related trapezius myalgia. More studies are needed to understand possible mechanisms that would explain the occurrence of moth-eaten fibers.
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| 2. |
- Larsson, Barbro, 1952-, et al.
(författare)
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Surface electromyography and peak torque of repetitive maximum isokinetic plantar flexions in relation to aspects of muscle morphology
- 2006
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Ingår i: Journal of Electromyography & Kinesiology. - : Elsevier BV. - 1050-6411 .- 1873-5711. ; 16:3, s. 281-290
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the relationships between surface electromyography (EMG [Mean frequency of the power spectrum (MNF)]) and peak torque variables obtained during 100 maximum concentric plantar flexions with the right limb at 60 degrees s(-1) and different muscle morphological variables. Surface EMG was recorded from the right gastrocnemius lateralis and muscle biopsies were taken from the same site as the EMG electrodes were positioned. Muscle fibre area and fibre type composition were determined on serial muscle cross sections using both histochemistry (myofibrillar adenosine triphosphatase) and immunohistochemistry (monoclonal antibodies against specific myosin heavy chain isoforms). Forty-three female and nine male students participated in the study. Gastrocnemius lateralis contained predominantly type I fibres (50%) and type IIA fibres (40%) in both sexes and large individual differences were found. Principal component analysis (PCA) was used for the intercorrelation analyses, and projection to latent structures (PLS) was used for the multivariate regression analysis. MNF correlated positively with different fibre areas and with the proportion of type I fibres. Fibre areas and sex were the most important factors in the regression of maximum peak torque. High proportion of type I fibres and sex were the most important regressors of peak torque endurance normalised for lean body mass. More studies are needed to understand the complex interrelationships between intrinsic muscle properties and the frequency content of the surface EMG before theoretical models can be formulated that incorporate both fibre areas and fibre type proportions.
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| 3. |
- Dyverfeldt, Petter, 1980-, et al.
(författare)
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Quantification of intravoxel velocity standard deviation and turbulence intensity by generalizing phase-contrast MRI
- 2006
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Ingår i: Magnetic Resonance in Medicine. - : Wiley. - 0740-3194 .- 1522-2594. ; 56:4, s. 850-858
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Tidskriftsartikel (refereegranskat)abstract
- Turbulent flow, characterized by velocity fluctuations, is a contributing factor to the pathogenesis of several cardiovascular diseases. A clinical noninvasive tool for assessing turbulence is lacking, however. It is well known that the occurrence of multiple spin velocities within a voxel during the influence of a magnetic gradient moment causes signal loss in phase-contrast magnetic resonance imaging (PC-MRI). In this paper a mathematical derivation of an expression for computing the standard deviation (SD) of the blood flow velocity distribution within a voxel is presented. The SD is obtained from the magnitude of PC-MRI signals acquired with different first gradient moments. By exploiting the relation between the SD and turbulence intensity (TI), this method allows for quantitative studies of turbulence. For validation, the TI in an in vitro flow phantom was quantified, and the results compared favorably with previously published laser Doppler anemometry (LDA) results. This method has the potential to become an important tool for the noninvasive assessment of turbulence in the arterial tree.
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| 4. |
- Ebbers, Tino, 1972-
(författare)
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Flow Imaging: Cardiac Applications of 3D Cine Phase-Contrast MRI
- 2011
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Ingår i: Current Cardiovascular Imaging Reports. - : Springer Science and Business Media LLC. - 1941-9074 .- 1941-9066. ; 4:2, s. 127-133
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Forskningsöversikt (refereegranskat)abstract
- Global and regional blood flow dynamics are of pivotal importance to cardiac function. Fluid mechanical forces can affect hemolysis and platelet aggregation, as well as myocardial remodeling. In recent years, assessment of blood flow patterns based on time-resolved, three-dimensional, three-directional phase-contrast MRI (3D cine PC MRI) has become possible and rapidly gained popularity. Initially, this technique was mainly known for its intuitive and appealing visualizations of the cardiovascular blood flow. Most recently, the technique has begun to go beyond compelling images toward comprehensive and quantitative assessment of blood flow. In this article, cardiac applications of 3D cine PC MRI data are discussed, starting with a review of the acquisition and analysis techniques, and including descriptions of promising applications of cardiac 3D cine PC MRI for the clinical evaluation of myocardial, valvular, and vascular disorders.
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| 5. |
- Elmberg, Viktor, et al.
(författare)
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Reference equations for breathlessness during incremental cycle exercise testing
- 2023
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Ingår i: ERJ Open Research. - : European Respiratory Society. - 2312-0541. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Exertional breathlessness is commonly assessed using incremental exercise testing (IET), but reference equations for breathlessness responses are lacking. We aimed to develop reference equations for breathlessness intensity during IET.METHODS: A retrospective, consecutive cohort study of adults undergoing IET was carried out in Sweden. Exclusion criteria included cardiac or respiratory disease, death or any of the aforementioned diagnoses within 1 year of the IET, morbid obesity, abnormally low exercise capacity, submaximal exertion or an abnormal exercise test. Probabilities for breathlessness intensity ratings (Borg CR10) during IET in relation to power output (%predWmax), age, sex, height and body mass were analysed using marginal ordinal logistic regression. Reference equations for males and females were derived to predict the upper limit of normal (ULN) and the probability of different Borg CR10 intensity ratings.RESULTS: 2581 participants (43% female) aged 18-90 years were included. Mean breathlessness intensity was similar between sexes at peak exertion (6.7±1.5 versus 6.4±1.5 Borg CR10 units) and throughout exercise in relation to %predWmax. Final reference equations included age, height and %predWmax for males, whereas height was not included for females. The models showed a close fit to observed breathlessness intensity ratings across %predWmax values. Models using absolute W did not show superior fit. Scripts are provided for calculating the probability for different breathlessness intensity ratings and the ULN by %predWmax throughout IET.CONCLUSION: We present the first reference equations for interpreting breathlessness intensity during incremental cycle exercise testing in males and females aged 18-90 years.
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| 6. |
- Zhu, Changlian, 1964, et al.
(författare)
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X chromosome-linked inhibitor of apoptosis protein reduces oxidative stress after cerebral irradiation or hypoxia-ischemia through up-regulation of mitochondrial antioxidants.
- 2007
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Ingår i: The European journal of neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 26:12, s. 3402-10
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that X chromosome-linked inhibitor of apoptosis protein (XIAP) counteracts oxidative stress in two essentially different disease-related models of brain injury, hypoxia-ischemia and irradiation, as judged by lower expression of nitrotyrosine (5-fold) and 4-hydroxy-2-nonenal (10-fold) in XIAP-overexpressing compared with wild-type mice. XIAP overexpression induced up-regulation of at least three antioxidants residing in mitochondria, superoxide dismutase 2, thioredoxin 2 and lysine oxoglutarate reductase. Cytochrome c release from mitochondria was reduced in XIAP-overexpressing mice. Hence, in addition to blocking caspases, XIAP can regulate reactive oxygen species in the brain, at least partly through up-regulation of mitochondrial antioxidants. XIAP-induced prevention of oxidative stress was not secondary to tissue protection because although XIAP overexpression provides tissue protection after hypoxia-ischemia, it does not prevent tissue loss after irradiation. This is a previously unknown role of XIAP and may provide the basis for development of novel protective strategies for both acute and chronic neurodegenerative diseases, where oxidative stress is an integral component of the injury mechanisms involved.
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| 7. |
- Östman-Smith, Ingegerd, 1947, et al.
(författare)
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Electrocardiographic amplitudes : a new risk factor for sudden death in hypertrophic cardiomyopathy.
- 2010
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Ingår i: European Heart Journal. - : Oxford University Press. - 0195-668X .- 1522-9645. ; 31:4, s. 439-449
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Assessment of ECG-features as predictors of sudden death in adults with hypertrophic cardiomyopathy (HCM).METHODS AND RESULTS: ECG-amplitude sums were measured in 44 normals, 34 athletes, a hospital-cohort of 87 HCM-patients, and 29 HCM-patients with sudden death or cardiac arrest (HCM-CA). HCM-patients with sudden death or cardiac arrest had substantially higher ECG-amplitudes than the HCM-cohort for limb-lead and 12-lead QRS-amplitude sums, and amplitude-duration products (P = 0.00003-P = 0.000002). Separation of HCM-CA from the HCM-cohort is obtained by limb-lead QRS-amplitude sum >or=7.7 mV (odds ratio 18.8, sensitivity 87%, negative predictive value (NPV) 94%, P < 0.0001), 12-lead amplitude-duration product >or=2.2 mV s (odds ratio 31.0, sensitivity 92%, NPV 97%, P < 0.0001), and limb-lead amplitude-duration product >or=0.70 mV s (odds ratio 31.5, sensitivity 93%, NPV 96%, P < 0.0001). Sensitivity in HCM-patients <40 years is 90, 100, and 100% for those ECG-variables, respectively. Qualitative analysis showed correlation with cardiac arrest for pathological T-wave-inversion (P = 0.0003), ST-depression (P = 0.0010), and dominant S-wave in V(4) (P = 0.0048). A risk score is proposed; a score >or=6 gives a sensitivity of 85% but a higher positive predictive value than above measures. Optimal separation between HCM-CA <40 years and athletes is obtained by a risk score >or=6 (odds ratio 345, sensitivity 85%, specificity 100%, P < 0.0001).CONCLUSION: Twelve-lead ECG is a powerful instrument for risk-stratification in HCM.
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| 8. |
- Sjörs, Anna, 1981-, et al.
(författare)
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Salivary cortisol response to acute stress and its relation to psychological factors in women with chronic trapezius myalgia-A pilot study
- 2010
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Ingår i: Psychoneuroendocrinology. - : Elsevier BV. - 1873-3360 .- 0306-4530. ; 35:5, s. 674-685
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated differences in HPA axis function, measured as salivary cortisol concentrations, between 18 women with chronic trapezius myalgia (MYA) and 30 healthy female controls (CON). In addition, the interactions between HPA axis reactions to psychosocial stress and aspects of pain, health and psychological symptoms were analyzed. Salivary cortisol was measured both in daily life, to assess the circadian profile, and in the laboratory during light repetitive work and standardized psychosocial stress (Trier Social Stress Test, TSST). MYA and CON exhibited similar circadian rhythms and comparable salivary cortisol response magnitudes after TSST. In subjects defined as responders to the TSST, the mean peak time point of the cortisol response after TSST differed significantly between MYA and CON. Furthermore, negative psychological states and higher pain intensity were related to a slower HPA axis response to TSST. Low circadian variations in cortisol and smaller cortisol responses to TSST were found among subjects scoring high on anxiety sensitivity. Thus, a relatively favorable sample of female chronic trapezius myalgia patients exhibited normal circadian rhythm and normal salivary cortisol response magnitudes after a psychosocial stress test. In the subgroup of responders, the MYA group showed indications of a slower salivary cortisol response to psychosocial stress. Further studies are needed to elucidate the possibility of altered HPA axis activity in terms of a slower salivary cortisol response. (c) 2009 Elsevier Ltd. All rights reserved.
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| 9. |
- Olsson, Max, et al.
(författare)
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Factors most strongly associated with breathlessness in a population aged 50-64 years
- 2024
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Ingår i: ERJ Open Research. - : European Respiratory Society. - 2312-0541. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Breathlessness is a troublesome and prevalent symptom in the population, but knowledge of related factors is scarce. The aim of this study was to identify the factors most strongly associated with breathlessness in the general population and to describe the shapes of the associations between the main factors and breathlessness.METHODS: A cross-sectional analysis was carried out of the multicentre population-based Swedish CArdioPulmonary bioImage Study (SCAPIS) of adults aged 50 to 64 years. Breathlessness was defined as a modified Medical Research Council breathlessness rating ≥2. The machine learning algorithm extreme gradient boosting (XGBoost) was used to classify participants as either breathless or nonbreathless using 449 factors, including physiological measurements, blood samples, computed tomography cardiac and lung measurements, lifestyle, health conditions and socioeconomics. The strength of the associations between the factors and breathlessness were measured by SHapley Additive exPlanations (SHAP), with higher scores reflecting stronger associations.RESULTS: A total of 28 730 participants (52% women) were included in the study. The strongest associated factors for breathlessness were (in order of magnitude): body mass index ( SHAP score 0.39), forced expiratory volume in 1 s (0.32), physical activity measured by accelerometery (0.27), sleep apnoea (0.22), diffusing lung capacity for carbon monoxide (0.21), self-reported physical activity (0.17), chest pain when hurrying (0.17), high-sensitivity C-reactive protein (0.17), recent weight change (0.14) and cough (0.13).CONCLUSION: This large population-based study of men and women aged 50-64 years identified the main factors related to breathlessness that may be prevented or amenable to public health interventions.
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| 10. |
- Pesonen, Ida, et al.
(författare)
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High prevalence of interstitial lung abnormalities in middle-aged never-smokers
- 2023
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Ingår i: ERJ Open Research. - : European Respiratory Society. - 2312-0541. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Interstitial lung abnormalities (ILA) are incidental findings on chest computed tomography (CT). These patterns can present at an early stage of fibrotic lung disease. Our aim was to estimate the prevalence of ILA in the Swedish population, in particular in never-smokers, and find out its association with demographics, comorbidities and symptoms.METHODS: Participants were recruited to the Swedish CArdioPulmonary BioImage Study (SCAPIS), a population-based survey including men and women aged 50-64 years performed at six university hospitals in Sweden. CT scan, spirometry and questionnaires were performed. ILA were defined as cysts, ground-glass opacities, reticular abnormality, bronchiectasis and honeycombing.FINDINGS: Out of 29 521 participants, 14 487 were never-smokers and 14 380 were men. In the whole population, 2870 (9.7%) had ILA of which 134 (0.5%) were fibrotic. In never-smokers, the prevalence was 7.9% of which 0.3% were fibrotic. In the whole population, age, smoking history, chronic bronchitis, cancer, coronary artery calcium score and high-sensitive C-reactive protein were associated with ILA. Both ILA and fibrotic ILA were associated with restrictive spirometric pattern and impaired diffusing capacity of the lung for carbon monoxide. However, individuals with ILA did not report more symptoms compared with individuals without ILA.INTERPRETATION: ILA are common in a middle-aged Swedish population including never-smokers. ILA may be at risk of being underdiagnosed among never-smokers since they are not a target for screening.
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