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Hamstring muscle injury is highly prevalent in sports involving repeated maximal sprinting. Although neuromuscular fatigue is thought to be a risk factor, the mechanisms underlying the fatigue response to repeated maximal sprints are unclear. Here, we show that repeated maximal sprints induce neuromuscular fatigue accompanied with a prolonged strength loss in hamstring muscles. The immediate hamstring strength loss was linked to both central and peripheral fatigue, while prolonged strength loss was associated with indicators of muscle damage. The kinematic changes immediately after sprinting likely protected fatigued hamstrings from excess elongation stress, while larger hamstring muscle physiological cross-sectional area and lower myoblast:fibroblast ratio appeared to protect against fatigue/damage and improve muscle recovery within the first 48 h after sprinting. We have therefore identified novel mechanisms that likely regulate the fatigue/damage response and initial recovery following repeated maximal sprinting in humans.

A general occurrence of the phenomenon of priming effect (PE) across varying land use and soil types has not been established so far, particularly on a large geographical scale. Moreover, the impacts of soil properties and soil organic matter (SOM) distribution among physical fractions on the magnitude of PE are still unclear. We addressed these knowledge gaps by incubating thirty five soils with or without addition of C-13 labeled cellulose for 262 days. The soils were sampled from different land uses and depths of contrasting soil types from five continents (Asia, Europe, America, Australia and Africa). Results showed positive PE in all soils including grassland, cropland, forest, savannah and orchard. On average, the cumulative PE represented 27.0 +/- 28.7% of the CO2 efflux in control soils and 28.48 +/- 21.08% of the remaining/unrespired cellulose-C. The PE was 72.1% higher in surface than deep soils suggesting that surface soils are more prone to PE induced by cellulose addition. Variations in PE were mainly explained by soil characteristics and not by land use. We found that the PE increased with the relative abundance of SOM not associated with minerals and rich in nitrogen (N). The observation of systematic positive PE in all soils suggested that microbial co-metabolism to decompose SOM is a widespread microbial strategy. Our results also support the idea that microorganisms use co-metabolism to mine nutrients in SOM since they target N-rich fractions. However, other mechanisms are also at play since positive PE was maintained despite the high availability of mineral nutrients. Overall, PE is a worldwide process playing a major role for soil C dynamics, especially in N-rich soils.

In autoimmune thyroid disease, thyroid epithelial cells (TEC) express major histocompatibility complex (MHC) class II molecules, potentially enabling them to present thyroid self-antigens to CD4-positive T cells. However, despite this, TEC may fail to present endogenous antigen as a result of limited processing or MHC class II loading capacity, or inadequate MHC class II levels. We addressed these issues using the cloned rat TEC line, Fischer rat thyroid cell line (FRTL5), which was transfected using an adenoviral expression vector that expressed ovalbumin (OVA) as an integral membrane protein. OVA-expressing FRTL5 cells very efficiently activated a panel of OVA-specific, class II-restricted T-cell hybridomas. This response was dependent on induction of MHC class II molecules by interferon-gamma (IFN-gamma) and was blocked by anti-MHC class II antibodies. Poor responses were seen to exogenously added OVA or OVA peptides. These results provide the most direct evidence to date that TEC can form MHC class II-peptide complexes derived from self-antigen in sufficient quantities to activate T cells.

Purpose. Explore compliance with occlusion treatment of amblyopia in the Monitored and Randomized Occlusion Treatment of Amblyopia Studies (MOTAS and ROTAS), using objective monitoring.\ud \ud Methods. Both studies had a three-phase protocol: initial assessment, refractive adaptation, and occlusion. In the occlusion phase, participants were instructed to dose for 6 hours/day (MOTAS) or randomized to 6 or 12 hour/day (ROTAS). Dose was monitored continuously using an occlusion dose monitor (ODM).\ud \ud Results. One hundred and fifty-two patients (71 male, 81 female; 122 Caucasian, 30 non-Caucasian) of mean ± SD age 68 ± 18 months participated. Amblyopia was defined as an interocular acuity difference of at least 0.1 logMAR and was associated with anisometropia in 50, strabismus in 44, and both (mixed) in 58. Median duration of occlusion was 99 days (interquartile range 72 days). Mean compliance was 44%, mean proportion of days with no patch worn was 42%. Compliance was lower (39%) on weekends compared with weekdays (46%, P = 0.04), as was the likelihood of dosing at all (52% vs. 60%, P = 0.028). Compliance was lower when attendance was less frequent (P < 0.001) and with prolonged treatment duration (P < 0.001). Age, sex, amblyopia type, and severity were not associated with compliance. Mixture modeling suggested three subpopulations of patch day doses: less than 30 minutes; doses that achieve 30% to 80% compliance; and doses that achieve around 100% compliance.\ud \ud Conclusions. This study shows that compliance with patching treatment averages less than 50% and is influenced by several factors. A greater understanding of these influences should improve treatment outcome. (ClinicalTrials.gov number, NCT00274664.)