| 1. |
- Molin, Carl Johan, et al.
(författare)
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High-resistance strength training does not affect nerve cross sectional area – An ultrasound study
- 2017
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Ingår i: Clinical Neurophysiology Practice. - : Elsevier BV. - 2467-981X. ; 2, s. 163-169
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThe aim was to study the effect of high-resistance strength training on peripheral nerve morphology, by examining properties of peripheral nerves as well as distal and proximal muscle thickness with ultrasound, comparing healthy individuals who perform and do not perform high-resistance strength training.MethodsNeuromuscular ultrasound was used to examine cross sectional area (CSA) of the median and musculocutaneous nerves, and muscle thickness of the abductor pollicis brevis muscle, biceps brachii muscle, quadriceps muscle and extensor digitorum brevis muscle, in 44 healthy individuals, of whom 22 performed regular high-resistance strength training.ResultsNo difference in nerve CSA was found between trained and untrained individuals although trained individuals had thicker biceps brachii muscles. The CSA of the median nerve in the forearm correlated with participants’ height and was significantly larger in men than women.ConclusionsIn this cohort, CSA of the median and musculocutaneous nerves was not affected by strength training, whereas gender had a prominent effect both on CSA and muscle thickness.SignificanceThis is the first study to examine the effect of high-resistance strength training on peripheral nerves with neuromuscular ultrasound.
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| 2. |
- Molin, Carl Johan, 1989-
(författare)
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New Biomarkers for Neuromuscular Function and Myasthenia Gravis
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Myasthenia gravis (MG) is an autoimmune disorder, which is caused by autoantibodies against the acetylcholine receptor (AChR). The cardinal symptom is muscle fatigue, which can range from slight weakness of the extraocular muscles (causing droopy eyelids or double vision), to paralysis of the respiratory muscles. Antibodies towards other muscle proteins have been discovered, and MG is now considered a very heterogeneous disease with several subgroups. The severity of symptoms in MG patients is often fluctuating, and the antibody titers do not correlate with disease severity or treatment response. Therefore, there is a great need for reliable biomarkers in MG, both for assessing neuromuscular function, but also for clinical aspects such as disease progression and subgrouping.In Study I, the use of compound motor action potential (CMAP) as a biomarker for muscle status was examined in trained and untrained individuals. We found that trained individuals have a higher CMAP in proximal muscles, and the CMAP value in the biceps correlate with muscle strength in these individuals, indicating that CMAP can be used as a biomarker for muscle function. In Study II, subjects from study I were examined with ultrasound to assess the effect of high-resistance strength training (HRST) on peripheral nerves, and to compare muscle thickness. We did not find a difference in nerve cross-sectional area between the two groups. Trained individuals had thicker biceps muscles. The results from study I and II has led to CMAP and ultrasound being used to evaluate the result of physical exercise as an intervention in MG patients.In Study III, the expression of inflammatory proteins in the sera of MG patients was compared to healthy controls, in search for possible biomarkers. We found eleven proteins to be elevated, which provide new insight to the inflammatory response in MG and have possible functions as new biomarkers of inflammatory activity.In Study IV, the effect of thymectomy on the potential microRNA MG biomarkers miR-150-5p and miR-21-5p was examined. A decrease in miR-150-5p was seen 24 months after thymectomy, which further validate the use of miR-150-5p as a disease-specific biomarker for clinical outcome in AChR positive MG patients.
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| 3. |
- Westerberg, Elisabet, 1971-, et al.
(författare)
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The impact of physical exercise on neuromuscular function in Myasthenia gravis patients : A single-subject design study
- 2018
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Ingår i: Medicine. - : Lippincott Williams & Wilkins. - 0025-7974 .- 1536-5964. ; 97:31
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for tailored exercise recommendations to patients with Myasthenia Gravis (MG). A few pilot studies have recently shown that physical exercise in accordance with general recommendations to healthy adults can be applied safely to patients with mild MG symptoms. How physical exercise affects muscle parameters and risk factors for life-style diseases in patients with MG is, however, only poorly known. We evaluated functional skeletal muscle parameters in 11 MG patients, before and after conducting a 12-week supervised physical therapy regimen of aerobic and high-resistance strength training. After the training program, parameters of the proximal leg muscle rectus femoris improved: compound motor action potential (from 4.5 ± 2.6 to 5.3 ± 2.8 mV, p=0.016), isometric muscle force (from 25.2 ± 4.4 to 30.2 ± 3.8 kg; p=0.014) and ultrasound muscle thickness (from 19.6 ± 5.6 to 23.0 ± 3.9 mm, p=0.0098) all increased. Further, physical performance-based measures improved, including the 30-Second Chair Stand Test (median change +2, p=0.0039) as well as the clinical MG composite score (from 3[2-5] to 2 [0-4], p=0.043). These findings indicate that MG patients can improve their functional muscle status as a result of aerobic and high-resistance strength training, especially in proximal leg muscles. This is important knowledge when physical therapy is considered for this patient group, for whom no guidelines on physical exercise currently exist.
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| 4. |
- Stålberg, Erik, et al.
(författare)
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Reference values for jitter recorded by concentric needle electrodes in healthy controls : A multicenter study.
- 2016
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 53:3, s. 351-362
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The aim of this study was to create reference values for jitter measured with concentric needle electrodes.METHODS: Operators worldwide contributed recordings from orbicularis oculi (OO), frontalis (FR), and extensor digitorum (ED) muscles in healthy controls. Criteria for acceptable signal quality were agreed upon in advance. Fifteen or 20 recordings of acceptable quality from each muscle were required for voluntary and electrical stimulation recordings, respectively.RESULTS: Recordings from 59 to 92 subjects were obtained for each muscle and activation type. Outlier limits for mean consecutive difference and individual jitter data for voluntary activation were: OO, 31 and 45 µs; FR, 28 and 38 µs; ED, 30 and 43 µs; and for electrical stimulation they were: OO, 27 and 36 µs; FR, 21 and 28 µs; ED, 24 and 35 µs.CONCLUSION: Reference jitter values from concentric needle electrode recordings were developed from signals of defined quality while seeking to avoid creating supernormal values.
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| 5. |
- Widenfalk, Johan, 1972-, et al.
(författare)
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Treatment of transected peripheral nerves with artemin improved motor neuron regeneration, but did not reduce nerve injury-induced pain behaviour.
- 2009
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - : Informa UK Limited. - 0284-4311 .- 1651-2073. ; 43:5
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Tidskriftsartikel (refereegranskat)abstract
- Incomplete recovery of function and neuropathic pain are common problems after peripheral nerve injury. To develop new treatment strategies for peripheral nerve injuries we investigated whether the neurotrophic factor artemin could improve outcome after sciatic nerve injuries in rats. Artemin is a member of the glial cell line-derived neurotrophic factor (GDNF) family and exerts neuroprotective effects on sensory neurons as well as influencing behavioural thermal sensitivity. We additionally evaluated if fibrin sealant, which is sometimes used as a nerve glue, had any effects on neuropathic pain-related behaviour. After the sciatic nerve had been transected, 30 animals were randomised to one of three groups: treatment with a fibrin sealant that contained artemin in conjunction with sutures; fibrin sealant with no artemin (sham) in conjunction with sutures; or sutures alone (n=10 in each group). Motor function, sensory function, and autotomy were evaluated from 1 to 12 weeks after injury. Retrograde flourogold tracing 12 weeks after injury showed that the addition of artemin increased the number of regenerating motor neurons. However, it did not improve their performance, as measured by the Sciatic Function Index, compared with sham or suture alone. Animals treated with artemin had a non-significant increase in motor nerve conduction velocity compared with sham. However, artemin did not reverse nerve injury-induced pain behaviour such as cold or heat hypersensitivity. Fibrin sealant in itself did not ameliorate motor performance, or regeneration of motor neurons, or give rise to nerve injury-induced pain behaviour. The results indicate that artemin is of value as a treatment for peripheral nerve injuries, although the effects were limited. As the artemin high-affinity receptor GFRalpha-3 is present in Schwann cells and not in motor neurons, the effect on motor neuron axon regeneration may result from an indirect effect through Schwann cells in the injured nerve.
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