Search results for "ACTIVATION"

Muscle-Tendon Interaction During Human Dolphin-Kick Swimming

2019

Without high impact forces, it is not clear how humans can utilize tendon elasticity during low-impact activities. The purpose of the present study was to examine the muscle-tendon behavior together with the electromyographic (EMG) activities of the vastus lateralis (VL) muscle during the human dolphin-kicking. In a swimming pool, each subject (n = 11) swam the 25 m dolphin-kicking at two different speeds (NORMAL and FAST). Surface EMGs were recorded from the VL and biceps femoris (BF) muscles. Simultaneous recordings of the knee joint angle by electro-goniometer and of the VL fascicle length by ultrasonography were used to calculate the muscle-tendon unit and tendinous length of VL (LMTU a…

Autoimmune endocrine ophthalmopathy and retrobulbar antigens.

1995

Endocrine Ophthalmopathy (EO) is based on autoimmune processes that lead to lymphocyte infiltration of the retrobulbar space. In this study, antigenic character of retrobulbar adipose, connective and muscle tissue as well as of cultured fibroblasts and myoblasts were examined. Samples were obtained from EO patients (n = 13, 8 fem., age 26-82 years, median 47 years) undergoing orbital decompression surgery. Retrobulbar and abdominal tissue from 7 controls (4 fem., 48 - 74 y) was investigated, too. Tissues were homogenized and the proteins were separated by SDS-PAGE according to molecular weight. In order to recover the separated proteins in soluble form, an electroelution technique was emplo…

Dépendance de la fatigue à la longueur musculaire : approche mécanique et neurophysiologique

2006

The objective of this work is to evaluate the fatigue dependency on the knee extensor muscles length. Exercises varying the type of contraction (isometric and eccentric) and intensity of contraction (maximal and sub-maximal) are performed in order to disrupt the neuromuscular system by different factors of fatigue: central and peripheral. These exercises are performed at two muscular lengths (S and L, corresponding respectively to 40 and 100° of knee flexion). Neuromuscular parameters (maximal torque, muscular twitch, voluntary activation level, electromyographic activity, etc.) are analyzed in pre- and post-fatigue conditions in the type of contraction required by the fatiguing exercise. I…

Friend retrovirus infection of myeloid dendritic cells impairs maturation, prolongs contact to naïve T cells, and favors expansion of regulatory T ce…

2007

AbstractRetroviruses have developed immunmodulatory mechanisms to avoid being attacked by the immune system. The mechanisms of this retrovirus-associated immune suppression are far from clarified. Dendritic cells (DCs) have been attributed a decisive role in these pathogenic processes. We have used the Friend retrovirus (FV) mouse model in order to acquire further knowledge about the role of infection of DCs in virus-induced immunosuppression. About 20% of the myeloid DCs that were generated from the bone marrow of FV-infected mice carried FV proteins. The infection was productive, and infected DCs transmitted the virus in cell culture and in vivo. FV infection of DCs led to a defect in DC …

Defective stromal remodeling and neutrophil extracellular traps in lymphoid tissues favor the transition from autoimmunity to lymphoma

2013

Abstract Altered expression of matricellular proteins can become pathogenic in the presence of persistent perturbations in tissue homeostasis. Here, we show that autoimmunity associated with Fas mutation was exacerbated and transitioned to lymphomagenesis in the absence of SPARC (secreted protein acidic rich in cysteine). The absence of SPARC resulted in defective collagen assembly, with uneven compartmentalization of lymphoid and myeloid populations within secondary lymphoid organs (SLO), and faulty delivery of inhibitory signals from the extracellular matrix. These conditions promoted aberrant interactions between neutrophil extracellular traps and CD5+ B cells, which underwent malignant …

SIRT1 prevents genotoxic stress-induced p53 activation in acute myeloid leukemia

2014

SIRT1 is an important regulator of cellular stress response and genomic integrity. Its role in tumorigenesis is controversial. Whereas sirtuin 1 (SIRT1) can act as a tumor suppressor in some solid tumors, increased expression has been demonstrated in many cancers, including hematologic malignancies. In chronic myeloid leukemia, SIRT1 promoted leukemia development, and targeting SIRT1 sensitized chronic myeloid leukemia progenitors to tyrosine kinase inhibitor treatment. In this study, we investigated the role of SIRT1 in acute myeloid leukemia (AML). We show that SIRT1 protein, but not RNA levels, is overexpressed in AML samples harboring activating mutations in signaling pathways. In FMS-l…

Insights on Kawasaki disease and multisystem inflammatory syndrome: relationship with COVID-19 infection.

2021

At the beginning of coronavirus disease 2019 (COVID-19) children seemed to be less affected and with milder symptoms than adults. Afterward, however, a warning was released regarding the possible association between COVID-19 and Kawasaki disease (KD) or Kawasaki-like disease. Thereafter, labels of Paediatric Inflammatory Multisystem Syndrome Temporally associated with SARS-CoV-2 (PIMS-TS) in Europe and Multisystem Inflammatory Syndrome in Children (MIS-C) in the USA were coined to refer to this new disease entity. The reality is that PIMS-TS/MIS-C resembles certain KD complications such as toxic shock syndrome and macrophage activation syndrome than to classic KD. PIMS-TS/MIS-C and KD share…

Treatment of chronic pain associated with bruxism through Myofunctional therapy

2017

<p> </p><p><span> </span>Temporomandibular disorders such as bruxism may cause painful clinical conditions and over time lead to chronic facial pain. A combination of therapeutic strategies that are usually undertaken by dentists and gnathologists to reduce bruxism episodes and consequently pain, are myofunctional therapy, pharmacological treatment, intraoral interventions and behavioural treatments. The aim of this work was to understand if myofuntional therapy alone can be a useful therapy for the reduction of chronic facial pain. 24 patients, 9 male and 15 female, age ranging between 25 and 45, were treated with a myofunctional therapy for 9 month. Each pati…

2019

Post-activation potentiation (PAP) is a well-described phenomenon with a short half-life (~28 s) that enhances muscle force production at submaximal levels of calcium saturation (i.e., submaximal levels of muscle activation). It has been largely explained by an increased myosin light chain phosphorylation occurring in type II muscle fibers, and its effects have been quantified in humans by measuring muscle twitch force responses to a bout of muscular activity. However, enhancements in (sometimes maximal) voluntary force production detected several minutes after high-intensity muscle contractions are also observed, which are also most prominent in muscles with a high proportion of type II fi…

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2020

Intracellular acid stress inhibits plant growth by unknown mechanisms and it occurs in acidic soils and as consequence of other stresses. In order to identify mechanisms of acid toxicity, we screened activation-tagging lines of Arabidopsis thaliana for tolerance to intracellular acidification induced by organic acids. A dominant mutant, sbt4.13-1D, was isolated twice and shown to over-express subtilase SBT4.13, a protease secreted into endoplasmic reticulum. Activity measurements and immuno-detection indicate that the mutant contains less plasma membrane H+-ATPase (PMA) than wild type, explaining the small size, electrical depolarization and decreased cytosolic pH of the mutant but not orga…