Influenza Infection has Fiber Type-Specific Effects on Cellular and Molecular Skeletal Muscle Function in Aged Mice.

Skeletal muscle myopathies represent a common non-pulmonary manifestation of influenza infection, leading to reduced physical function and hospitalization in older adults. However, underlying mechanisms remain poorly understood. Our study examined the effects of influenza virus A pulmonary infection on contractile function at the cellular (single fiber) and molecular (myosin-actin interactions and myofilament properties) levels in soleus and extensor digitorum longus muscles of aged (20 months) C57BL/6 male mice that were healthy or flu-infected for 7 (7-days post-infection; 7-DPI) or 12 days (12-DPI). Cross-sectional area (CSA) of myosin heavy chain (MHC) IIA and IIB fibers was reduced at 12-DPI relative to 7-DPI and healthy. Maximal isometric force in MHC IIA fibers was also reduced at 12-DPI relative to 7-DPI and healthy, resulting in no change in specific force (maximal isometric force divided by CSA). In contrast, MHC IIB fibers produced greater isometric force and specific force at 7-DPI compared to 12-DPI or healthy. The increased specific force in MHC IIB fibers was likely due to greater myofilament lattice stiffness and/or an increased number or stiffness of strongly bound myosin-actin cross-bridges. At the molecular level, cross-bridge kinetics were slower in MHC IIA fibers with infection, while changes in MHC IIB fibers were largely absent. In both fiber types, greater myofilament lattice stiffness was positively related to specific force. This study provides novel evidence that cellular and molecular contractile function is impacted by influenza infection in a fiber type-specific manner, suggesting potential molecular mechanisms to help explain the impact of flu-induced myopathies.

Treating ischemia via recruitment of antigen-specific T cells.

Ischemic diseases are a leading cause of mortality and can result in autoamputation of lower limbs. We explored the hypothesis that implantation of an antigen-releasing scaffold, in animals previously vaccinated with the same antigen, can concentrate TH2 T cells and enhance vascularization of ischemic tissue. This approach may be clinically relevant, as all persons receiving childhood vaccines recommended by the Centers for Disease Control and Prevention have vaccines that contain aluminum, a TH2 adjuvant. To test the hypothesis, mice with hindlimb ischemia, previously vaccinated with ovalbumin (OVA) and aluminum, received OVA-releasing scaffolds. Vaccinated mice receiving OVA-releasing scaffolds locally concentrated antigen-specific TH2 T cells in the surrounding ischemic tissue. This resulted in local angiogenesis, increased perfusion in ischemic limbs, and reduced necrosis and enhanced regenerating myofibers in the muscle. These findings support the premise that antigen depots may provide a treatment for ischemic diseases in patients previously vaccinated with aluminum-containing adjuvants.

The Danger Signal Extracellular ATP Is Involved in the Immunomediated Damage of α-Sarcoglycan-Deficient Muscular Dystrophy.

In muscular dystrophies, muscle membrane fragility results in a tissue-specific increase of danger-associated molecular pattern molecules (DAMPs) and infiltration of inflammatory cells. The DAMP extracellular ATP (eATP) released by dying myofibers steadily activates muscle and immune purinergic receptors exerting dual negative effects: a direct damage linked to altered intracellular calcium homeostasis in muscle cells and an indirect toxicity through the triggering of the immune response and inhibition of regulatory T cells. Accordingly, pharmacologic and genetic inhibition of eATP signaling improves the phenotype in models of chronic inflammatory diseases. In α-sarcoglycanopathy, eATP effects may be further amplified because α-sarcoglycan extracellular domain binds eATP and displays an ecto-ATPase activity, thus controlling eATP concentration at the cell surface and attenuating the magnitude and/or the duration of eATP-induced signals. Herein, we show that in vivo blockade of the eATP/P2X purinergic pathway by a broad-spectrum P2X receptor-antagonist delayed the progression of the dystrophic phenotype in α-sarcoglycan-null mice. eATP blockade dampened the muscular inflammatory response and enhanced the recruitment of forkhead box protein P3-positive immunosuppressive regulatory CD4+ T cells. The improvement of the inflammatory features was associated with increased strength, reduced necrosis, and limited expression of profibrotic factors, suggesting that pharmacologic purinergic antagonism, altering the innate and adaptive immune component in muscle infiltrates, might provide a therapeutic approach to slow disease progression in α-sarcoglycanopathy.

Sodium 4-phenylbutyrate reduces myofiber damage in a mouse model of Duchenne muscular dystrophy.

We performed a placebo-controlled pre-clinical study to determine if sodium 4-phenylbutyrate (4PB) can reduce contraction-induced myofiber damage in the mdx mouse model of Duchenne muscular dystrophy (DMD). At 72 h post-eccentric contractions, 4PB significantly increased contractile torque and reduced myofiber damage and macrophage infiltration. We conclude that 4PB, which is approved by Health Canada (Pheburane) and the United States Food and Drug Administration (Buphenyl) for urea cycle disorders, might modify disease severity in patients with DMD.

Benidipine prevents oxidative stress, inflammatory changes and apoptosis related myofibril damage in isoproterenol-induced myocardial infarction in rats.

OBJECTIVE: The effects of benidipine on oxidative stress and myocardial apoptosis were assessed in isoproterenol (ISO)-induced myocardial infarction (MI) in wistar rats. MATERIALS AND METHOD: Animals were pretreated with benidipine (1, 3, 10 µg/kg/day Body weight) intravenously for a period of 28 days. After pretreatment, ISO (85 mg/kg Body weight, subcutaneous) was injected in rats at an interval of 24 h to induce MI. Myocardial oxidative stress, cardiac biomarkers, apoptosis, inflammatory mediators, and ultrastructural architecture of the cardiac tissue were assessed in ISO-induced MI in rats. RESULT: Significant variation in the level of TBA, antioxidant enzymes (GSH, CAT, SOD, GPx, GRx, GST) in myocardium, cardiac biomarkers (CK-MB, LDH) in serum, Caspase-3, C-reactive protein (CRP), and alteration in ultrastructural architecture of cardiac tissue confirmed the cardiotoxicity induced by ISO. Pretreatment with benidipine preserved the lipid peroxide and antioxidant enzymes, and furthermore showed maintained levels of myocardial biomarker, CRP and caspase-3. Ultrastructure architecture of cardiac tissue was also found to be well preserved. CONCLUSION: The present study suggested cardioprotective effect of benidipine which may possibly be due to its antioxidant activity and antiapoptotic nature.

Pathogenic aspects of dermatomyositis, polymyositis and overlap myositis.

Inflammatory myopathies (IMs) often have distinct histopathologic features suggesting humorally mediated involvement of the microcirculation in dermatomyositis (DM), including early capillary deposition of the complement C5b-9 membranolytic attack complex (MAC) and secondary ischaemic changes; and CD8 T-cell-mediated and MHC1-restricted autoimmune attack of myofibers in polymyositis (PM) and inclusion body myositis. Novel insights in these specific diseases include emerging evidence that capillary loss involves whole microvascular units in DM, and that regulatory T-cells strongly protect myofibers from experimental autotoxic attack in PM. However, all IMs do not exhibit pathophysiology-relevant histopathologic features of DM or PM. Autoimmune necrotizing myopathies (AINM) occur in the absence of endomysial inflammatory cells and may be specifically associated with anti-SRP autoantibodies. Moreover, IM histopathological features may be scarce, unspecific and overlapping. Therefore, increasing attention is paid to features shared by IMs regardless of their type, relevant to the innate immune response and to non-immune mechanisms. Innate immune responses to myodamage (and/or as yet unknown stimuli), involves release of chemokines, activation of specific Toll-like receptors (TLRs) and complex Th-1, Th-17 and other cytokine interplays; it triggers DC recruitment and maturation, and is associated with type 1 IFN signature (especially in DM where type 1 IFN-producing cells called plasmacytoid DCs are mainly detected). Non-immune mechanisms mainly include endoplasmic reticulum (ER) stress induced in myofibers by up-regulation of MHC-class I antigens (as typically observed in PM with a diffuse pattern and in DM with perifascicular predominance). ER stress may favour autoimmune reactions but may also be associated with myofiber damage and dysfunction in the absence of lymphocytes. Overlap myositis (OM) may be associated with other connective tissue diseases and a variety of autoantibodies, such as those directed against tRNA synthetase. Myositis specific autoantibodies are mainly expressed by regenerating myofibers, that may also express MHC-1 and endogenous ligand-binding TLRs, thus drawing a picture in which the regenerating myofiber plays a central pathophysiologic role.

[Myofibrillar protein tropomyosin and allergic cross-reactivity].

Myofibrillar protein tropomyosin (TM) is a normal physiological protein participating in regulation of muscular contraction. It is widely prevalent among living organisms. This explains cross-reactivity of allergic patients to home dust, sea fish, cockroaches, etc. The presence of similar IgE-binding epitopes in TM of different origin is a key factor in development of cross-reactivity (CR). CR to TM is a general biological phenomenon. We consider modified TM as a basic component in design of allergovaccines of a new generation.

Determination of slow-tonic MyHC immunoreactivity is an important step in the evaluation of muscle spindles in porcine extraocular muscles.

We have tested our hypothesis suggesting (i) that for the reliable determination and counting of muscle spindles (Msp) at the light microscopy level in extraocular muscles (EOM), analysis of the spindle specific myosin heavy chain (MyHC) immunoreactivity of intrafusal fibers, especially after staining with anti-slow-tonic MyHC antibodies, is the most convenient tool, (ii) that the number of Msp determined by the slow-tonic MyHC immunoreactivity of intrafusal fibers in EOM is much lower than that based on histological examination and (iii) that the previously reported numbers of Msp based on histological examination of EOM could be overestimated. In order to determine the number and distribution of Msp and to analyze the MyHC isoform immunoreactivity of intrafusal fibers in porcine EOM, paraffin sections of three 9-month-old pig medial (MR) and lateral rectus (LR), levator palpebrae (LP) and retractor bulbi (RB) muscles were stained histologically or using specific monoclonal antibodies (mAbs) against MyHC isoforms. Msp in recti and LP muscles studied by immunocytochemistry contained nuclear bag (NB) fiber(s) reacting with mAbs against slow-tonic, slow-twitch, alpha-cardiac and neonatal MyHCs, but not with the mAb against fast-twitch MyHC, which, on the contrary, stained nuclear chain (NC) fibers. Based on determination of spindle specific slow-tonic MyHC isoform immunoreactivity we have found 72 Msp in the MR and 68 Msp in the LR and 12 Msp in LP muscles, which was only 62, 55 and 32% of the Msp total counts according to histological examination, respectively. In the RB muscle, we have even found only 15 spindle-like-structures composed of encapsulated thin muscle fibers, which possessed only a reaction with anti-fast-twitch MyHC mAb, but lacked slow-tonic, slow-twitch or alpha-cardiac MyHCs immunoreactivity. Our analysis of porcine EOM confirmed the above suggestions, demonstrating, for the first time in the pig, the presence of "false Msp" mimicking encapsulated muscle fibers on histological sections that lack spindle specific MyHC immunoreactivity. In analogy with other muscles we suggest that "false Msp" are not innervated by sensory axons and therefore do not contribute to the physiological sensation of the muscle length changes. Our results thus show that the reliable identification of functionally effective Msp in EOM must involve immunohistochemical analysis of spindle specific MyHC isoforms of intrafusal fibers, as "false" spindles appearing on histologically stained sections as encapsulated muscle fibers could be regarded as "true" Msp and thus increase the spindle number counts in earlier studies.

[Ultrastructural peculiarities of heart of rats of various ages at different levels of antigen load].

The aim of the research was to investigate electron-microscopic peculiarities of heart at different levels of antigen loading using adult and old aged gnotobiont rats, conventional rats and rats with experimental autoimmune cardiomyopathy. The results of investigations showed that the ultrasrtuctural characteristics of heart greatly depend on microbiological status and age of experimental animals. The ultrasrtucture of heart of adult rats mostly depend on the level of intensity of antigen loading. In all experimental groups of old rats the subcellular differences had the same directions. Although, it must be mentioned that there was not significant correlation between the level of heart damage and intensity of antigen loading. According to this, age-related changes depend not only on microbiological status of organism, but on genetically determined peculiarities of internal regulative processes taking place during the ontogenesis. Thus, the received results may be used to identify age-related changes, which give us the possibility for the differentiation between age-related and pathological peculiarities.

Dermatitis herpetiformis and partial IgA deficiency.

Although the specific IgA autoantibody responsible for the pathogenesis of dermatitis herpetiformis (DH) is unknown, the presence of IgA is considered essential in the pathogenesis of DH. To date, no cases of IgA deficiency have been reported in DH. In contrast, IgA deficiency is found in 2% to 3% of patients with celiac disease, a rate 10 to 15 times higher than the normal population. We report 2 patients with DH who also have partial IgA deficiency. We evaluated the sera of these patients for the presence of IgA autoantibodies to endomysium, tissue transglutaminase, epidermal transglutaminase, and gliadin. Both patients were found to have IgA endomysial and tissue transglutaminase antibodies, and serologic markers for DH. Corresponding IgG autoantibodies were not useful serologic markers of DH in the setting of IgA deficiency, as they often are in celiac disease. We then screened 98 DH sera for total IgA levels and identified 1 additional case with IgA deficiency. In conclusion, DH may develop in patients with partial IgA deficiency, indicating that pathogenically directed IgA antibodies are likely sufficient for cutaneous IgA deposition in this disease.

The prevalence of celiac disease among family members of celiac disease patients.

INTRODUCTION: Celiac disease (CD) is more common in certain risk groups. Family members of known celiac patients represent the most important group. Serological screening enables us to detect patients before they develop serious complications. HLA typing has also proven to be a valuable diagnostic tool, especially in excluding the disease. METHODS: To assess the prevalence of CD among family members, we screened 106 first-degree relatives (73 parents, 33 siblings; mean age 27.9 years) of 45 celiac patients in NE Slovenia. We analysed antigliadin (AGA) and antiendomysium (EMA) antibodies. Levels of IgG and IgAAGA were determined using the ELISA method, and EMA using indirect immunofluorescence. Serologically positive patients were recalled for intestinal biopsy and were HLA typed. Intestinal biopsy was performed by peroral aspiration capsule or during upper GI endoscopy. Biopsy specimens were examined histologically. RESULTS: Six family members (5.67%) were both AGA IgG and EMA positive, and one (0.94%) was only EMA positive. All were either HLA DQ2 or DQ8 positive. Nine family members (8.49%) were only AGA IgG positive, two of them lacked the HLA DQ susceptibility alleles. Intestinal biopsy was performed in six family members, and the diagnosis of CD confirmed in five. All were both AGA IgG and EMA positive. They were either symptom-free or had only mild gastrointestinal symptoms, and carried the known HLA DQ risk alleles. The minimum prevalence of CD among family members in NE Slovenia can therefore be estimated at 4.72%. DISCUSSION: The prevalence of CD among first-degree relatives is much higher than the prevalence of the disease in the general population. Most of these patients have an atypical form of the disease and would therefore be overlooked without an active search. Serological testing is recommended for all first-degree relatives of CD patients; they should also undergo HLA typing to detect those whose HLA phenotype is consistent with CD. This approach can also help in excluding individuals who do not need further diagnostic procedures for CD.

Proteasomal expression, induction of immunoproteasome subunits, and local MHC class I presentation in myofibrillar myopathy and inclusion body myositis.

Inclusion body myositis (IBM) and myofibrillar myopathy (MM) are diseases characterized by the abnormal accumulation of proteins in muscle fibers, including desmin, alphaB-crystallin, gelsolin, actin, kinases, and phospho-tau, along with ubiquitin in muscle fibers, suggesting abnormal protein degradation as a possible cause of the surplus myopathy. Since the ubiquitin-proteasome system plays a crucial role in non-lysosomal protein degradation, the present study has examined by immunohistochemistry the expression of components of the catalytic core of 20S proteasomes and its regulators: 19S and PA28alpha/beta, and the expression of immunoproteasome subunits LMP2, LMP7, and MECL1 in 8 patients with MM and 10 patients with IBM. The patients with MM were from 6 unrelated families, 2 sporadic cases, I with autosomal recessive and 5 with autosomal dominant inheritance. One sporadic patient had a de novo R406W mutation in the desmin gene, and 1 patient with autosomal dominant MM had a single amino acid deletion at position 366 in the desmin gene. Increased immunoreactivity to 20S, 19S, and PA28alpha/beta colocalizing abnormal protein deposits, as revealed in consecutive serial sections, was seen in all cases with MM and IBM. In all cases, the subunits of the immunoproteasome LMP2, LMP7, and MECL1 colocalized with proteasomal immunoreactivity and abnormal protein accumulation. Immunohistochemistry revealed focal MHC class I immunoreactivity in the cytoplasmic membrane of muscle fibers in IBM and in association with protein aggregates in IBM, and to a lesser degree, in MM. The present findings provide a link between abnormal protein accumulation and altered proteasomal expression in IBM and MM.

Effectiveness of the sorbitol H2 breath test in detecting histological damage among relatives of coeliacs.

BACKGROUND: Small intestinal lesions have a wide severity in coeliac disease (CD), and early diagnosis is important in preventing neoplastic and non-neoplastic disorders related to CD. The aim of this study was to compare the effectiveness of the sorbitol H2 breath test (H2-BT) and serological tests (antigliadin (AGA), antiendomysium (EMA) and anti-tissue transglutaminase (anti-tTG)) as screening tests in the detection and estimation of CD prevalence in 1st-degree relatives. METHODS: Screening was performed in 111 1st-degree relatives of 37 coeliac families. Sorbitol H2-BT, AGA, EMA and anti-tTG antibodies were used to select the candidates for small-bowel biopsy. Relatives with abnormal serological tests and/or with sorbitol H2-BT positivity underwent a small-bowel biopsy. Small-bowel biopsy was also performed in relatives negative in all tests but with clinical complaints or suspected of having CD, and intestinal lesions were expressed according to the Marsh classification. RESULTS: CD was diagnosed in 49/111 screened relatives (44.14%): 5 showed Marsh IIIc, 8 Marsh IIIb, 16 Marsh IIIa, 13 Marsh II and 7 Marsh I lesions. Nineteen relatives showed the classical form of the disease, while the subclinical and silent forms were recorded in 20 and 10, respectively. AGA, EMA and anti-tTG showed strong positivity only in severe intestinal damage (Marsh IIIb-c lesions) (but overall positivity was 36.73%, 38.78% and 44.89% for AGA, EMA and anti-tTG, respectively), while sorbitol H2-BT showed strong positivity also in patients with slight histological damage (Marsh I-IIIa) (overall positivity was 83.67%). CONCLUSIONS: A significant proportion of coeliacs may be missed if relatives are screened by serology only, while the efficacy of sorbitol H2-BT in screening relatives is confirmed. This study confirms that neither a breath test nor serology can replace intestinal biopsy, which remains the gold standard for the diagnosis of CD.

Prevalence of coeliac disease: unexplained age-related variation in the same population.

BACKGROUND: The aims of this work were (a) to evaluate the prevalence of coeliac disease (CD) in a large sample of the Brazilian general population and (b) to compare CD prevalence between children and adults. METHODS: The study group comprised 4405 subjects (2629 F and 1776 M). Age distributions were 2034 (1-14 years), 848 (15-29), 584 (30-44), 667 (45-59) and 272 above 60. The immunoglobulin A antiendomysial antibody (IgA-EMA) test was used as the serological screening tool. All sera were submitted to turbidimetric measurement of IgA levels and those with IgA deficiency to the IgG antigliadin (IgG-AGA) test. The small intestinal biopsy was recommended for subjects showing either (a) IgA-EMA positivity or (b) selective IgA deficiency (SigAD) and IgG-AGA positivity. RESULTS: There were 16 EMA positive out of 4405 sera tested. SigAD was found in five cases (one adult and four children). Two of these children tested positive for IgG-AGA and underwent jejunal biopsy that, in both cases, disclosed a normal mucosa. Overall, 17 out of 18 eligible subjects performed the small intestinal biopsy. The prevalence of biopsy-proven CD in this study group was 3.41 per 1000 individuals. If all 18 EMA-positive patients were included, the overall prevalence would become 3.63 per 1000. The prevalence in adults and children was 2.11 per 1000 and 5.44 per 1000, respectively. CONCLUSION: This work supports previous findings showing that CD is not a rare disorder in Brazil and that there is an unexplained difference in the prevalence of CD between adults and children.

Better dietary compliance in patients with coeliac disease diagnosed in early childhood.

BACKGROUND: In coeliac disease (CD) there is a permanent gluten intolerance requiring life-long adherence to a strict gluten-free diet (GFD). An inadequate diet increases the risk for long-term complications. Coeliac patients often have great difficulty in maintaining a strictly GFD. We aimed to study whether young adults with CD diagnosed before the age of 4 years have a better dietary compliance than patients diagnosed later in life. METHOD: Twenty-nine adults with CD diagnosed in childhood were studied. They had had CD for 17-24 (mean 20) years. Their compliance to GFD was assessed using a questionnaire and serological markers (IgA and IgG anti-endomysium antibodies and IgA anti-tissue transglutaminase antibodies). RESULTS: At least 80% of the coeliac patients who had been diagnosed before the age of 4 years complied with the GFD compared to 36% of the CD patients older than 4 years at diagnosis (P < 0.05). CONCLUSION: This is the first study to show that patients with CD diagnosed before 4 years of age keep to a GFD significantly better than patients diagnosed after 4 years. It is thus important to diagnose childhood CD as early as possible in order to minimize the risk for reduced well-being and other potentially serious complications in coeliac individuals on an inadequate diet.

Association between anti-endomysial antibody and total intestinal villous atrophy in children with coeliac disease.

BACKGROUND: There is growing evidence to suggest that detection of anti-gliadin antibody (AGA) and anti-endomysial antibody (EmA) can serve as sensitive markers of the degree of histological abnormalities in patients with coeliac disease. AIM: To evaluate the association between the presence of AGA and EmA and villous atrophy in intestinal biopsies of children with suspected coeliac disease. SETTINGS AND DESIGN: Intestinal samples of 46 children with failure to thrive, chronic diarrhoea, malabsorption and short stature with either AGA and/or EmA positivity were evaluated, retrospectively. The diagnosis of coeliac disease was based on ESPGHAN criteria. METHODS AND MATERIAL: Patients with total villous atrophy who fulfilled the ESPGHAN criteria for the diagnosis of coeliac disease were diagnosed to have coeliac disease. Nine patients without villous atrophy were taken as negative controls for this study. AGA-IgA was measured both by immunoflourescence (IF) and ELISA and EmA-IgA by IF while patients were on normal diet. Relationship between autoantibody positivity and intestinal total villous atrophy was evaluated. RESULTS: Overall positivity for AGA IgA was 85% (39/46) by IF+ELISA and EmA positivity was 85% (39/46) by IF within the study group. Histological examination revealed total villous atrophy with lymphocyte infiltration and crypt hyperplasia in 37 (80%) patients. AGA IgA was positive in 14 (38%) and 31 (84%) of these children by ELISA and IF, respectively. EmA positivity was detected in 35/37 (95%) cases with atrophy and 4/9 (44%) without atrophy (p=0.002). Thirty out of 37 (81%) patients with villous atrophy had both AGA IgA (IF) and EmA positivity (p=0.186). All of the sixteen patients that had both positive AGA IgA (ELISA+IF) and EmA had total villous atrophy (p=0.037). CONCLUSION: A significant association between total villous atrophy and EmA positivity has been documented in this study.

Prevalence of celiac disease in Down syndrome in the United States.

BACKGROUND: Numerous studies in Europe have documented a high prevalence of celiac disease in Down syndrome. This study was undertaken to estimate the prevalence of celiac disease in Down syndrome in the southeastern United States. METHODS: Seventy-five patients with Down syndrome were screened using immunoglobulin (Ig)A-anti antiendomysium antibodies, IgA-antigliadin antibodies, and total IgA level. When either antiendomysium or antigliadin antibodies produced positive findings, patients were referred to a pediatric gastroenterologist for consideration of a duodenal biopsy. RESULTS: Thirteen percent (10/75) were positive for antiendomysium antibodies. Half of these patients were also positive for antigliadin antibodies. Six of 10 patients positive for antiendomysium antibodies underwent intestinal biopsy. Changes consistent with celiac disease were documented in five. Histologic findings ranged from focal to total villous atrophy. None had IgA deficiency. CONCLUSIONS: There was a high prevalence of positivity to antiendomysium antibody in Down syndrome. Antiendomysium antibody was a more sensitive screening test than antigliadin antibody. The prevalence of celiac disease in Down syndrome in the southeastern United States was 1 in 14 cases. Screening with antiendomysium antibody and IgA for all children with Down syndrome is recommended, even if there are no gastrointestinal symptoms.

Endomysium antibodies are superior to gliadin antibodies in screening for coeliac disease in patients presenting supposed functional gastrointestinal symptoms.

OBJECTIVE: To study the accuracy of IgA- and IgC-gluten antibodies and endomysium antibodies as screening tools for endoscopy with small bowel biopsy for histologic diagnosing of coeliac disease. DESIGN: Comparing serology with histologic examination--the "gold standard" for diagnosing coeliac disease. SETTINGS: 1. The municipality of Osthammar, Sweden. 2. The catchment area of the University Hospital, Uppsala, Sweden. PATIENTS: 1. A random subsample (50 with dyspepsia, 50 with irritable bowel syndrome and 50 symptomless) of a representative sample from an adult Swedish general population (20-80 years; n = 1260). 2. All patients with a diagnosis of coeliac disease admitted to the University Hospital in Uppsala, Sweden during the course of 10 months. MAIN OUTCOME MEASURES: The accuracy of IgA- and IgG-gluten antibodies and endomysium antibodies. RESULTS: There were no significant correlations between IgA-gluten antibodies and IgG-gluten antibodies, on the one hand, and symptoms or symptom severity, on the other. Using duodenal biopsy results as the gold standard, IgA-gluten antibodies had a low specificity and IgG-gluten antibodies a low sensitivity, whereas endomysium antibodies had an excellent accuracy. CONCLUSION: Endomysium antibodies seem to be the screening test of choice. The load of diagnostic upper endoscopies would be considerably decreased compared to using gluten antibodies.

Satellite cell regulation following myotrauma caused by resistance exercise.

It is generally accepted that the primary mechanisms governing skeletal muscle hypertrophy are satellite cell activation, proliferation, and differentiation. Specific growth factors and hormones modulate satellite cell activity during normal muscle growth, but as a consequence of resistance exercise additional regulators may stimulate satellite cells to contribute to gains in myofiber size and number. Present knowledge of the regulation of the cellular, biochemical and molecular events accompanying skeletal muscle hypertrophy after resistance exercise is incomplete. We propose that resistance exercise may induce satellite cells to become responsive to cytokines from the immune system and to circulating hormones and growth factors. The purpose of this paper is to review the role of satellite cells and growth factors in skeletal muscle hypertrophy that follows resistance exercise.