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  • 401.
    Yu, Ji-Guo
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Liu, Jing-Xia
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Carlsson, Lena
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Stål, Per S
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Re-evaluation of sarcolemma injury and muscle swelling in human skeletal muscles after eccentric exercise2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 4, article id e62056Article in journal (Refereed)
    Abstract [en]

    The results regarding the effects of unaccustomed eccentric exercise on muscle tissue are often conflicting and the aetiology of delayed onset muscle soreness (DOMS) induced by eccentric exercise is still unclear. This study aimed to re-evaluate the paradigm of muscular alterations with regard to muscle sarcolemma integrity and fibre swelling in human muscles after voluntary eccentric exercise leading to DOMS. Ten young males performed eccentric exercise by downstairs running. Biopsies from the soleus muscle were obtained from 6 non-exercising controls, 4 exercised subjects within 1 hour and 6 exercised subjects at 2-3 days and 7-8 days after the exercise. Muscle fibre sarcolemma integrity, infiltration of inflammatory cells and changes in fibre size and fibre phenotype composition as well as capillary supply were examined with specific antibodies using enzyme histochemistry and immunohistochemistry. Although all exercised subjects experienced DOMS which peaked between 1.5 to 2.5 days post exercise, no significant sarcolemma injury or inflammation was detected in any post exercise group. The results do not support the prevailing hypothesis that eccentric exercise causes an initial sarcolemma injury which leads to subsequent inflammation after eccentric exercise. The fibre size was 24% larger at 7-8 days than at 2-3 days post exercise (p<0.05). In contrast, the value of capillary number per fibre area tended to decrease from 2-3 days to 7-8 days post exercise (lower in 5 of the 6 subjects at 7-8 days than at 2-3 days; p<0.05). Thus, the increased fibre size at 7-8 days post exercise was interpreted to reflect fibre swelling. Because the fibre swelling did not appear at the time that DOMS peaked (between 1.5 to 2.5 days post exercise), we concluded that fibre swelling in the soleus muscle is not directly associated with the symptom of DOMS.

  • 402.
    Yu, Ji-Guo
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Malm, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Eccentric contractions leading to DOMS do not cause loss of desmin nor fibre necrosis in human muscle.2002In: Histochemistry and Cell Biology, ISSN 0948-6143, E-ISSN 1432-119X, Vol. 118, no 1, p. 29-34Article in journal (Refereed)
    Abstract [en]

    High force eccentric muscle contractions can result in delayed onset muscle soreness (DOMS), prolonged loss of muscle strength, decreased range of motion, muscle swelling and an increase of muscle proteins in the blood. At the ultrastructural level Z-line streaming and myofibrillar disruptions have been taken as evidence for muscle damage. In animal models of eccentric exercise-induced injury, disruption of the cytoskeleton and the sarcolemma of muscle fibres occurs within the first hour after the exercise, since a rapid loss of staining of desmin, a cytoskeletal protein, and the presence of fibronectin, a plasma and extracellular protein, are observed within the muscle fibres. In the present study, biopsies from subjects who had performed different eccentric exercises and had developed DOMS were examined. Our aim was to determine whether eccentric exercise leading to DOMS causes sarcolemmal disruption and loss of desmin in humans. Our study shows that even though the subjects had DOMS, muscle fibres had neither lost staining for desmin nor contained plasma fibronectin. This study therefore does not support previous conclusions that there is muscle fibre degeneration and necrosis in human skeletal muscle after eccentric exercise leading to DOMS. Our data are in agreement with the recent findings that there is no inflammatory response in skeletal muscle following eccentric exercise in humans. In combination, these findings should stimulate the search for other mechanisms explaining the functional and structural alterations in human skeletal muscle after eccentric exercise.

  • 403.
    Yu, Ji-Guo
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Sewright, Kimberly
    Hubal, Monica
    Liu, Jing-Xia
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Schwartz, Lawrence
    Hoffman, Eric
    Clarkson, Priscilla
    Investigation of gene expression in C(2)C(12) Myotubes following simvastatin application and mechanical strain2009In: Journal of Atherosclerosis and Thrombosis, ISSN 1880-3873, E-ISSN 1340-3478, Vol. 16, no 1, p. 21-29Article in journal (Refereed)
    Abstract [en]

    Aim: The 3-hydroxy-3methylgutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are the most effective prescribed drugs for lowering serum cholesterol; however, although statins are extremely safe medications and have brought significant benefits to patients with hypercholesterolemia, they have been shown to produce myalgia, cramps, exercise intolerance and fatigue. The aim of the study was to investigate the molecular mechanisms that may mediate statin myopathy.

    Methods: We used DNA microarray analysis to examine the changes in gene expression profiles induced by 1 hour and 6 hours of statin treatment on differentiated C(2)C(12) myotubes. Four genes were selected for analysis at the protein level using Western blot analysis on myotubes treated with statin with or without additional mechanical stretching.

    Results: Eighty-five genes exhibited more than a 2-fold up- or down-regulation in expression, of which 46 have known biological functions related primarily to transmembrane transport, signal transduction, cell growth/maintenance, protein metabolism, or apoptosis. At protein level, three of the four proteins were induced (Adrb1, Socs4 and Cflar) and one was repressed (Birc4). Changes in protein expression largely mirrored the changes in their corresponding transcripts, although the fold-change was less dramatic. The addition of imposed muscle fiber stretching did not exacerbate the expression of these genes at the protein level with the exception of Cflar, a pro-apoptotic protein.

    Conclusion: These data suggested that alterations in the expressions of some statin-regulated genes could be causative factors for statin toxicity in muscle. Repression of the anti-apoptosis gene (Birc4) and activation of the pro-apoptosis gene (Cflar) indicated that cell death may play an important role in statin-induced myopathy.

  • 404.
    Yu, Ji-Guo
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Desmin and actin alterations in human muscles affected by delayed onset muscle soreness: a high resolution immunocytochemical study.2002In: Histochemistry and Cell Biology, ISSN 0948-6143, E-ISSN 1432-119X, Vol. 118, no 2, p. 171-9Article in journal (Refereed)
    Abstract [en]

    Lack of staining for desmin in muscles in animal models of eccentric exercise has been suggested to reflect disruption of the desmin intermediate filament network and proposed to cause disruption of the myofibrillar apparatus and deterioration of muscle fibers. In a recent study, we examined muscle biopsies from persons who had performed different eccentric exercise protocols, which induced delayed onset muscle soreness (DOMS). We were unable to verify that loss of staining for desmin was a feature of sore muscles. Nevertheless, we observed changes in the desmin cytoskeleton, but the meaning of the observations was not conclusive. In the present study, a high resolution immunocytochemical method was used to investigate the changes of desmin and actin in human muscles following a bout of eccentric exercise that lead to DOMS 2-3 days post-exercise. Biopsies were taken before exercise and 1 h and 2-3 and 7-8 days after exercise. Phalloidin, a ligand that labels filamentous actin, and anti-desmin antibodies were used to stain semithin (approximately 0.5 micro m) cryosections. At 1 h post-exercise, the staining of actin and desmin did not differ from the controls, whereas in biopsies taken 2-3 and 7-8 days after exercise, 12.5% (SD 5.8%) and 6.1% (SD 2.3%) fibers showed areas of increased staining for actin. Corresponding values for fibers with increased staining for both actin and desmin were 8.7% (SD 3.9%) and 11.4% (SD 4.6%), respectively. We suggest that the increased staining of actin and desmin reflects an increased synthesis of these proteins as part of an adaptation process following the unaccustomed eccentric exercise.

  • 405.
    Zeisig, Eva
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Ljung, B-O
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Danielson, Patrik
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Immunohistochemical evidence of local production of catecholamines in cells of the muscle origins at the lateral and medial humeral epicondyles: of importance for the development of tennis and golfer's elbow?2009In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 43, no 4, p. 269-275Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Tennis elbow (TE) is a painful condition affecting the common extensor origin at the lateral humeral epicondyle. Colour Doppler examination has shown increased blood flow at this site and the sensory, and sympathetic innervation patterns have been delineated. However, it is not known whether there is local production of catecholamines and/or acetylcholine in this tissue, which is the case in patellar and Achilles tendinopathies. OBJECTIVE: To investigate the possible presence of local production of catecholamines and acetylcholine in non-neuronal cells (fibroblasts) in connective tissue at the muscle origin at the lateral humeral epicondyle in patients with TE. DESIGN: Immunohistochemical studies were performed on biopsies taken from the extensor origin in patients with TE and in pain-free controls. For reference purpose, biopsies from the flexor origin in patients with golfer's elbow (GE) were also studied. PATIENTS: Seven patients with TE and four patients with GE. Six healthy asymptomatic individuals served as controls. Method: Immunohistochemistry, using antibodies detecting synthesising enzymes for catecholamines (tyrosine hydroxylase; TH) and acetylcholine (choline acetyltransferase; ChAT). RESULTS: TH-like immunohistochemical reactions were seen in fibroblasts in four of the seven patients with TE and two of the four patients with GE. No such reactions were detected in controls (0/6). No ChAT reactions were seen in any of the investigated specimens. CONCLUSIONS: There is evidence of local, non-neuronal production of catecholamines, but not acetylcholine, in fibroblasts in the tissue at the muscle origin at the lateral and medial epicondyles in patients with TE and GE, respectively, which might have an influence on blood vessel regulation and pain mechanisms in these conditions.

  • 406.
    Zhang, Cheng-Gang
    et al.
    Umeå University, Faculty of Medicine, Integrative Medical Biology, Anatomy.
    Ma, Jian-Jun
    Terenghi, Giorgio
    Mantovani, Cristina
    Wiberg, Mikael
    Umeå University, Faculty of Medicine, Integrative Medical Biology, Anatomy. Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Hand Surgery.
    Phrenic nerve transfer in the treatment of brachial plexus avulsion: an experimental study of nerve regeneration and muscle morphology in rats.2004In: Microsurgery, ISSN 0738-1085, E-ISSN 1098-2752, Vol. 24, no 3, p. 232-240Article in journal (Refereed)
    Abstract [en]

    The regeneration of motor and sensory neurons and the morphological changes of the target muscle after phrenic nerve transfer were investigated in adult rats. Six months following nerve transfer, 326.0 +/- 16.31 phrenic motoneurons regenerated into musculocutaneous nerve, which is not different from the normal number of phrenic motoneurons. The regenerated motoneurons exhibited a 14% nonsignificant hypertrophy. Of the dorsal root ganglia (DRG) neurons, 255.8 +/- 45.26 regenerated, which was significantly lower than the number of normal phrenic DRG neurons. The regenerated phrenic DRG neurons showed a 24% close-to-significant atrophy. The target muscle fiber morphology changed considerably after reinnervation. The present results suggest that the phrenic nerve has very good regenerative ability in terms of its motoneurons and a relatively insufficient sensory neuronal regeneration.

  • 407. Zhang, Cheng-Gang
    et al.
    Terenghi, Giorgio
    Mantovani, Cristina
    Wiberg, Mikael
    Umeå University, Faculty of Medicine, Integrative Medical Biology, Anatomy.
    Neuronal survival, regeneration and musclemorphology after posterior C7 nerve transfer: an experimental study.2006In: J Plast Reconstr Aesthet Surg, ISSN 1748-6815, Vol. 59, no 7, p. 717-25Article in journal (Refereed)
    Abstract [en]

    C7 nerve transfer has been widely used in treating brachial plexus avulsion injuries. Little is known regarding the survival and regeneration of C7 motor and sensory neurons including their morphological changes after this procedure and also the possible change of muscle fibre phenotype. In this experimental study, the posterior division of C7 nerve was transferred to the musculocutaneous nerve ipsilaterally, and using fluorescent tracing techniques, the C7 spinal cord segment and dorsal root ganglion were found to contain 630.9 +/- 86.7 motor neurons and 3916.0 +/- 517.3 sensory neurons, respectively. Six months following transfer, 90% of the motor neurons and 78% of the sensory neurons survived and approximately 40% of them had regenerated and all displayed normal soma size. After posterior C7 transfer and reinnervation, the target muscles showed a percentage pattern of distribution and mean fibre diameters similar to those seen in normal biceps muscle. The present study suggests that the posterior C7 nerve transfer provides sufficient number of neurons and satisfactory results for regeneration to obtain an acceptable functional recovery.

  • 408. Zhang, Cheng-Gang
    et al.
    Welin, Dag
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Novikov, Lev
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Kellerth, Jan-Olof
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Wiberg, Mikael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Hart, Andrew McKay
    Motorneuron protection by N-acetyl-cysteine after ventral root avulsion and ventral rhizotomy2005In: British Journal of Plastic Surgery, ISSN 0007-1226, E-ISSN 1465-3087, Vol. 58, no 6, p. 765-773Article in journal (Refereed)
    Abstract [en]

    Motor recovery after proximal nerve injury remains extremely poor, despite advances in surgical care. Several neurobiological hurdles are implicated, the most fundamental being extensive cell death within the motorneuron pool. N-acetyl-cysteine almost completely protects sensory neurons after peripheral axotomy, hence its efficacy in protecting motorneurons after ventral root avulsion/rhizotomy was investigated. In adult rats, the motorneurons supplying medial gastrocnemius were unilaterally pre-labelled with retrograde tracer (true-blue/fluoro-gold), prior to L5 and 6 ventral root avulsion, or rhizotomy. Groups received either intraperitoneal N-acetyl-cysteine (ip, 150 or 750 mg/kg/day), immediate or delayed intrathecal N-acetyl-cysteine treatment (it, 2.4 mg/day), or saline; untreated animals served as controls. Either 4 (avulsion model) or 8 (rhizotomy model) weeks later, the pre-labelled motorneurons' mean soma area and survival were quantified. Untreated controls possessed markedly fewer motorneurons than normal due to cell death (avulsion 53% death; rhizotomy 26% death, P<0.01 vs. normal). Motorneurons were significantly protected by N-acetyl-cysteine after avulsion (ip 150 mg/kg/day 40% death; it 30% death, P<0.01 vs. no treatment), but particularly after rhizotomy (ip 150 mg/kg/day 17% death; ip 750 mg/kg/day 7% death; it 5% death, P<0.05 vs. no treatment). Delaying intrathecal treatment for 1 week after avulsion did not impair neuroprotection, but a 2-week delay was deleterious (42% death, P<0.05 vs. 1-week delay, 32% death). Treatment prevented the decrease in soma area usually found after both types of injury. N-acetyl-cysteine has considerable clinical potential for adjuvant treatment of major proximal nerve injuries, including brachial plexus injury, in order that motorneurons may survive until surgical repair facilitates regeneration.

  • 409.
    Zhang, Wei
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Chen, Jialin
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Backman, Ludvig J.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Malm, Adam D.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Danielson, Patrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Ophthalmology.
    Surface Topography and Mechanical Strain Promote Keratocyte Phenotype and Extracellular Matrix Formation in a Biomimetic 3D Corneal Model2017In: Advanced Healthcare Materials, ISSN 2192-2640, E-ISSN 2192-2659, Vol. 6, no 5, article id UNSP 1601238Article in journal (Refereed)
    Abstract [en]

    The optimal functionality of the native corneal stroma is mainly dependent on the well-ordered arrangement of extracellular matrix (ECM) and the pressurized structure. In order to develop an in vitro corneal model, it is crucial to mimic the in vivo microenvironment of the cornea. In this study, the influence of surface topography and mechanical strain on keratocyte phenotype and ECM formation within a biomimetic 3D corneal model is studied. By modifying the surface topography of materials, it is found that patterned silk fibroin film with 600 grooves mm(-1) optimally supports cell alignment and ECM arrangement. Furthermore, treatment with 3% dome-shaped mechanical strain, which resembles the shape and mechanics of native cornea, significantly enhances the expression of keratocyte markers as compared to flat-shaped strain. Accordingly, a biomimetic 3D corneal model, in the form of a collagen-modified, silk fibroin-patterned construct subjected to 3% dome-shaped strain, is created. Compared to traditional 2D cultures, it supports a significantly higher expression of keratocyte and ECM markers, and in conclusion better maintains keratocyte phenotype, alignment, and fusiform cell shape. Therefore, the novel biomimetic 3D corneal model developed in this study serves as a useful in vitro 3D culture model to improve current 2D cultures for corneal studies.

  • 410.
    Ängquist, Karl-Axel
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Human skeletal muscle fibre structure: effects of physical training and arterial insufficiency1978Doctoral thesis, comprehensive summary (Other academic)
  • 411.
    Åberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Ljungberg, Christina
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Edin, E
    Jenmalm, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Millqvist, H
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Nordh, Erik
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neurophysiology.
    Wiberg, Mikael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Considerations in evaluating new treatment alternatives following peripheral nerve injuries: a prospective clinical study of methods used to investigate sensory, motor and functional recovery.2007In: J Plast Reconstr Aesthet Surg, ISSN 1748-6815, Vol. 60, no 2, p. 103-13Article in journal (Refereed)
    Abstract [en]

    The current problem finding reliable and objective methods for evaluating results after peripheral nerve repair is a challenge when introducing new clinical techniques. The aim of this study was to obtain reference material and to evaluate the applicability of different tests used for clinical assessment after peripheral nerve injuries. Fifteen patients with a history of complete median nerve transsection and repair, and 15 healthy volunteers were included. Each subject was investigated using a battery of conventional and new tests for functional, sensory and motor recovery including questionnaires, clinical evaluations, neurophysiological and physiological findings. The results were statistically analysed and comparisons were made within the patient group and between patients and healthy volunteers using a 'per protocol' and an 'intention to treat' approach. Criteria for success were stipulated in order to be able to judge the usefulness of each method. The results showed that 19 of 34 variables, representing six of 16 methods, were not able to fulfil the criteria and were thus questionable for the evaluations of nerve repair in a clinical trial setting. However, 2pd, sensory recovery according to the non-modified British Medical Research Council, sensory neurography, manual muscle test, electromyography, questionnaires (i.e. DASH and the 4 question form) and performance tests (i.e. AMPS and Sollerman's subtests 4 and 8) did fulfil the criteria defined for being useful.

  • 412.
    Åberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Ljungberg, Christina
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Edin, Ellenor
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Millqvist, Helena
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Nordh, Erik
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neurophysiology.
    Theorin, Anna
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Terenghi, Giorgio
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Wiberg, Mikael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Clinical evaluation of a resorbable wrap-around implant as an alternative to nerve repair: A prospective, assessor-blinded, randomised clinical study of sensory, motor and functional recovery after peripheral nerve repair.2009In: Journal of plastic, reconstructive & aesthetic surgery : JPRAS, ISSN 1748-6815, Vol. 62, no 11, p. 1503-1509Article in journal (Refereed)
    Abstract [en]

    Peripheral nerve injures are common and often result in impaired functional recovery. The majority of injuries involve the arm and/or the hand. The traditional treatment for peripheral nerve injuries is repair by using microsurgical techniques, either by primary nerve suture or nerve graft, but research to find more successful methods that could improve recovery is ongoing. Tubulisation has been investigated by several authors and is suggested as an alternative to microsurgical techniques. The resorbable poly[(R)-3-hydroxybutyrate] (PHB) is one of the materials that has been previously tested experimentally. In this prospective, randomised, assessor-blinded clinical study, PHB was investigated as an alternative to epineural suturing in the treatment of peripheral nerve injuries at the wrist/forearm level of the arm. Twelve patients, with a complete, common, sharp injury of the median and/or ulnar nerve at the wrist/forearm level, were treated by either using PHB or microsurgical epineural end-to-end suturing. All patients were assessed using a battery of tests, including evaluation of functional, sensory and motor recovery by means of clinical, neurophysiological, morphological and physiological evaluations at 2 weeks and 3, 6, 9, 12 and 18 months after surgery. No adverse events or complications considered as product related were reported, and thus PHB can be regarded as a safe alternative for microsurgical epineural suturing. The majority of the methods in the test battery showed no significant differences between the treatment groups, but one should consider that the study involved a limited number of patients and a high variability was reported for the evaluating techniques. However, sensory recovery, according to the British Medical Research Council score and parts of the manual muscle test, suggested that treating with PHB may be advantageous as compared to epineural suturing. This, however, should be confirmed by large-scale efficacy studies.

  • 413.
    Österlund, Catharina
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Extra- and intrafusal muscle fibre type compositions of the human masseter at young age.: In perspective of growth and functional maturation of the jaw-face motor system.2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Muscles control body posture and movement by extrafusal and intrafusal (muscle spindle) fibres. The purpose of this thesis was to provide insight into the muscular basis for human jaw function at young age. Extrafusal and intrafusal fibres in the young masseter, and for comparison young biceps, were examined for composition of fibre types and myosin heavy chain (MyHC) isoforms by means of morphological, enzyme-histochemical, biochemical and immuno-histochemical techniques. For evaluation of plasticity during life span the data for young muscles were compared with previous reported data for adult and elderly muscles.

    The results showed significant differences in extrafusal fibre types and MyHC expression between young masseter and young biceps and between young masseter and masseter in adults and elderly. Compared with young biceps, young masseter was more intricate in composition of extrafusal MyHC expression. Muscle spindles were larger and more frequent in the masseter than in the biceps. Masseter and biceps muscle spindles showed fundamental similarities but also marked differences in MyHC expression.

    The results suggest that the young masseter is specialized in fibre types already at young age and shows a unique fibre type growth pattern. Whereas masseter extrafusal fibres display marked plasticity in fibre types and MyHC isoforms during life span muscle spindles/intrafusal fibres are morphologically mature already at young age and precede extrafusal fibres in growth and maturation. Results showed similarities in intrafusal MyHC expression between young masseter and biceps, but also differences implying muscle specific proprioceptive control. Differences in fibre types and MyHC expression between young masseter and young biceps extrafusal fibres are proposed to reflect diverse evolutionary and developmental origins and accord with the masseter and biceps being separate allotypes of muscle.

  • 414.
    Österlund, Catharina
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Lindström, Mona
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Eriksson, Per-Olof
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology.
    Remarkable heterogeneity in myosin heavy-chain composition of the human young masseter compared with young biceps brachii2012In: Histochemistry and Cell Biology, ISSN 0948-6143, E-ISSN 1432-119X, Vol. 138, no 4, p. 669-682Article in journal (Refereed)
    Abstract [en]

    Adult human jaw muscles differ from limb and trunk muscles in enzyme-histochemical fibre type composition. Recently, we showed that the human masseter and biceps differ in fibre type pattern already at childhood. The present study explored the myosin heavy-chain (MyHC) expression in the young masseter and biceps muscles by means of gel electrophoresis (GE) and immuno-histochemical (IHC) techniques. Plasticity in MyHC expression during life was evaluated by comparing the results with the previously reported data for adult muscles. In young masseter, GE identified MyHC-I, MyHC-IIa MyHC-IIx and small proportions of MyHC-fetal and MyHC-alpha cardiac. Western blots confirmed the presence of MyHC-I, MyHC-IIa and MyHC-IIx. IHC revealed in the masseter six isomyosins, MyHC-I, MyHC-IIa, MyHC-IIx, MyHC-fetal, MyHC alpha-cardiac and a previously not reported isoform, termed MyHC-IIx'. The majority of the masseter fibres co-expressed two to four isoforms. In the young biceps, both GE and IHC identified MyHC-I, MyHC-IIa and MyHC-IIx. MyHC-I predominated in both muscles. Young masseter showed more slow and less-fast and fetal MyHC than the adult and elderly masseter. These results provide evidence that the young masseter muscle is unique in MyHC composition, expressing MyHC-alpha cardiac and MyHC-fetal isoforms as well as hitherto unrecognized potential spliced isoforms of MyHC-fetal and MyHC-IIx. Differences in masseter MyHC expression between young adult and elderly suggest a shift from childhood to adulthood towards more fast contractile properties. Differences between masseter and biceps are proposed to reflect diverse evolutionary and developmental origins and confirm that the masseter and biceps present separate allotypes of muscle.

  • 415.
    Österlund, Catharina
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology.
    Liu, Jing-Xia
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Eriksson, Per-Olof
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology.
    Intrafusal myosin heavy chain expression of human masseter and biceps muscles at young age shows fundamental similarities but also marked differences2013In: Histochemistry and Cell Biology, ISSN 0948-6143, E-ISSN 1432-119X, Vol. 139, no 6, p. 895-907Article in journal (Other academic)
    Abstract [en]

    Muscle spindles are skeletal muscle mechanoreceptors that provide proprioceptive information to the central nervous system. The human adult masseter muscle has greater number, larger and more complex muscle spindles than the adult biceps. For a better knowledge of muscle diversity and physiological properties, this study examined the myosin heavy chain (MyHC) expression of muscle spindle intrafusal fibres in the human young masseter and young biceps muscles by using a panel of monoclonal antibodies (mAbs) against different MyHC isoforms. Eight MyHC isoforms were detected in both muscles-slow-tonic, I, IIa, IIx, foetal, embryonic, α-cardiac and an isoform not previously reported in intrafusal fibres, termed IIx'. Individual fibres co-expressed 2-6 isoforms. MyHC-slow tonic separated bag(1), AS-bag(1) and bag(2) fibres from chain fibres. Typically, bag fibres also expressed MyHC-I and α-cardiac, whereas chain fibres expressed IIa and foetal. In the young masseter 98 % of bag(1) showed MyHC-α cardiac versus 30 % in the young biceps, 35 % of bag(2) showed MyHC-IIx' versus none in biceps, 17 % of the chain fibres showed MyHC-I versus 61 % in the biceps. In conclusion, the result showed fundamental similarities in intrafusal MyHC expression between young masseter and biceps, but also marked differences implying muscle-specific proprioceptive control, probably related to diverse evolutionary and developmental origins. Finding of similarities in MyHC expression between young and adult masseter and biceps muscle spindles, respectively, in accordance with previously reported similarities in mATPase fibre type composition suggest early maturation of muscle spindles, preceding extrafusal fibres in growth and maturation.

  • 416.
    Österlund, Catharina
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology.
    Liu, Jing-Xia
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Eriksson, Per-Olof
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology.
    Muscle spindle composition and distribution in human young masseter and biceps brachii muscles reveal early growth and maturation2011In: Anatomical Record, ISSN 0003-276X, E-ISSN 1097-0185, Vol. 294, no 4, p. 683-693Article in journal (Refereed)
    Abstract [en]

    Significant changes in extrafusal fiber type composition take place in the human masseter muscle from young age, 3-7 years, to adulthood, in parallel with jaw-face skeleton growth, changes of dentitions and improvement of jaw functions. As motor and sensory control systems of muscles are interlinked, also the intrafusal fiber population, that is, muscle spindles, should undergo age-related changes in fiber type appearance. To test this hypothesis, we examined muscle spindles in the young masseter muscle and compared the result with previous data on adult masseter spindles. Also muscle spindles in the young biceps brachii muscle were examined. The result showed that muscle spindle composition and distribution were alike in young and adult masseter. As for the adult masseter, young masseter contained exceptionally large muscle spindles, and with the highest spindle density and most complex spindles found in the deep masseter portion. Hence, contrary to our hypothesis, masseter spindles do not undergo major morphological changes between young age and adulthood. Also in the biceps, young spindles were alike adult spindles. Taken together, the results showed that human masseter and biceps muscle spindles are morphologically mature already at young age. We conclude that muscle spindles in the human young masseter and biceps precede the extrafusal fiber population in growth and maturation. This in turn suggests early reflex control and proprioceptive demands in learning and maturation of jaw motor skills. Similarly, well-developed muscle spindles in young biceps reflect early need of reflex control in learning and performing arm motor behavior.

  • 417.
    Österlund, Catharina
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Eriksson, Per-Olof
    Umeå University, Faculty of Medicine, Department of Odontology.
    Differences in fibre type composition between human masseter and biceps muscles in young and adults reveal unique masseter fibre type growth pattern2011In: Anatomical Record, ISSN 0003-276X, E-ISSN 1097-0185, Vol. 294, no 7, p. 1158-1169Article in journal (Refereed)
    Abstract [en]

    The human jaw system is different from those of other primates, carnivores, ruminants, and rodents in temporomandibular joint and muscle anatomy. In adults, jaw muscles also differ markedly from limb and trunk muscles in composition and distribution of fibre types. It can be assumed that age-related changes between young age to adulthood in terms of craniofacial growth, teeth eruption, and improvement of jaw functions are paralleled by alterations also in composition and distribution of jaw muscle fibre types. To address this question, we have examined the fibre type composition of the human masseter, a jaw closing muscle, at young age. For comparison, the young biceps brachii was examined. The results were compared with previous data for adult masseter and biceps muscles. Young masseter and biceps were similar in that type I fibres outnumbered other fibre types and were of the same diameter. However, they differed in composition of other fibre types. Young masseter contained fibre types I, IM, IIC, IIAB, IIB, and scarce IIA, with regional differences, whereas young biceps showed types I, IIA, IIAB, and few IIB. Young masseter differed from young biceps also by smaller type II fibre diameter and by containing fetal MyHC. In addition, the masseter and biceps differed in age-related changes of composition and distribution of fibre types between young age and adulthood. We conclude that the human masseter is specialized in fibre types already at young age and shows a unique fibre type growth pattern, in concordance with being a separate allotype of muscle.

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