An agent-based modelling approach to optimization of culture medium for generating muscle cells.

Methodologies for culturing muscle tissue are currently lacking in terms of quality and quantity of mature cells produced. We analyse images from experiments to quantify the effects of culture media composition on mouse-derived myoblast behaviour and myotube quality. Metrics of early indicators of cell quality were defined.

Online solid phase extraction high-performance liquid chromatography - Isotope dilution - Tandem mass spectrometry quantification of organophosphate pesticides, synthetic pyrethroids, and selected herbicide metabolites in human urine.

Analytical methods to quantify pesticide biomarkers in human population studies are critical for exposure assessment given the widespread use of pesticides for pest and weed control and their potential for affecting human health. We developed a method to quantify, in 0.2 mL of urine, concentrations of 10 pesticide biomarkers: four organophosphate insecticide metabolites (3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-6-methyl-4-pyrimidinol, para-nitrophenol, malathion dicarboxylic acid); five synthetic pyrethroid insecticide metabolites (4-fluoro-3-phenoxybenzoic acid, 3-phenoxybenzoic acid, cis and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (DCCA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid); and the herbicide 2,4-dichlorophenoxyacetic acid.

Generating fast-twitch myotubes in vitro with an optogenetic-based, quantitative contractility assay.

The composition of fiber types within skeletal muscle impacts the tissue's physiological characteristics and susceptibility to disease and ageing. In vitro systems should therefore account for fiber-type composition when modelling muscle conditions. To induce fiber specification in vitro, we designed a quantitative contractility assay based on optogenetics and particle image velocimetry.

Muscle is a stage, and cells and factors are merely players.

The incredible ability of satellite cells to regenerate muscle has captivated much of the research field's attention over the past decades. Versatile, enigmatic, vigorous, and skillful, the satellite cell is the optimal actor to cast in a regenerative epic, grabbing contracts and making headlines. However, the scenarios that play out during normal muscle usage, such as during exercise and aging, diverge from the experimental setup staged to spotlight satellite cells.

Muscle repair after physiological damage relies on nuclear migration for cellular reconstruction.

Regeneration of skeletal muscle is a highly synchronized process that requires muscle stem cells (satellite cells). We found that localized injuries, as experienced through exercise, activate a myofiber self-repair mechanism that is independent of satellite cells in mice and humans. Mouse muscle injury triggers a signaling cascade involving calcium, Cdc42, and phosphokinase C that attracts myonuclei to the damaged site via microtubules and dynein.

mRNA distribution in skeletal muscle is associated with mRNA size.

Skeletal muscle myofibers are large and elongated cells with multiple and evenly distributed nuclei. Nuclear distribution suggests that each nucleus influences a specific compartment within the myofiber and implies a functional role for nuclear positioning. Compartmentalization of specific mRNAs and proteins has been reported at the neuromuscular and myotendinous junctions, but mRNA distribution in non-specialized regions of the myofibers remains largely unexplored.

A flagellate-to-amoeboid switch in the closest living relatives of animals.

Amoeboid cell types are fundamental to animal biology and broadly distributed across animal diversity, but their evolutionary origin is unclear. The closest living relatives of animals, the choanoflagellates, display a polarized cell architecture (with an apical flagellum encircled by microvilli) that resembles that of epithelial cells and suggests homology, but this architecture differs strikingly from the deformable phenotype of animal amoeboid cells, which instead evoke more distantly related eukaryotes, such as diverse amoebae. Here, we show that choanoflagellates subjected to confinement become amoeboid by retracting their flagella and activating myosin-based motility.

An In Vitro System to Measure the Positioning, Stiffness, and Rupture of the Nucleus in Skeletal Muscle.

Nuclear positioning plays important roles for certain cellular functions. This is particularly relevant in skeletal muscle cells also known as myofibers in which nuclear positioning defects were shown to hinder muscle function. Myofibers are multinucleated cells with nuclei equally distributed at the periphery of the cell.

Local Arrangement of Fibronectin by Myofibroblasts Governs Peripheral Nuclear Positioning in Muscle Cells.

Skeletal muscle cells (myofibers) are rod-shaped multinucleated cells surrounded by an extracellular matrix (ECM) basal lamina. In contrast to other cell types, nuclei in myofibers are positioned just below the plasma membrane at the cell periphery. Peripheral nuclear positioning occurs during myogenesis and is driven by myofibril crosslinking and contraction.

Nuclear positioning in skeletal muscle.

Skeletal muscle cells possess a unique cellular architecture designed to fulfill their contractile function. Muscle cells (also known as myofibers) result from the fusion of hundreds of myoblasts and grow into a fiber of several centimeters in length. Cellular structures gradually become organized during muscle development to raise a mature contractile cell.

Myofibril contraction and crosslinking drive nuclear movement to the periphery of skeletal muscle.

Nuclear movements are important for multiple cellular functions, and are driven by polarized forces generated by motor proteins and the cytoskeleton. During skeletal myofibre formation or regeneration, nuclei move from the centre to the periphery of the myofibre for proper muscle function. Centrally located nuclei are also found in different muscle disorders.

The effect of compression socks worn during a marathon on hemostatic balance.

Introduction: Marathon running evokes parallel increases in markers of coagulation and fibrinolysis (i.e. hemostatic activation) immediately following strenuous, endurance exercise such that hemostatic balance is maintained.

N-WASP is required for Amphiphysin-2/BIN1-dependent nuclear positioning and triad organization in skeletal muscle and is involved in the pathophysiology of centronuclear myopathy.

Mutations in amphiphysin-2/BIN1, dynamin 2, and myotubularin are associated with centronuclear myopathy (CNM), a muscle disorder characterized by myofibers with atypical central nuclear positioning and abnormal triads. Mis-splicing of amphiphysin-2/BIN1 is also associated with myotonic dystrophy that shares histopathological hallmarks with CNM. How amphiphysin-2 orchestrates nuclear positioning and triad organization and how CNM-associated mutations lead to muscle dysfunction remains elusive.

Translation initiation factor eIF4F modifies the dexamethasone response in multiple myeloma.

Enhanced protein synthesis capacity is associated with increased tumor cell survival, proliferation, and resistance to chemotherapy. Cancers like multiple myeloma (MM), which display elevated activity in key translation regulatory nodes, such as the PI3K/mammalian target of rapamycin and MYC-eukaryotic initiation factor (eIF) 4E pathways, are predicted to be particularly sensitive to therapeutic strategies that target this process. To identify novel vulnerabilities in MM, we undertook a focused RNAi screen in which components of the translation apparatus were targeted.

Changes in muscle strength in patients with statin myalgia.

Statins can produce myalgia or muscle pain, which may affect medication adherence. We measured the effects of statins on muscle strength in patients with previous statin myalgia. Leg isokinetic extension average power at 60° per second (-8.

Treating adult attention deficit hyperactivity disorder in hospitalized psychiatric patients.

Objectives: We intend to review the importance of appropriately recognizing and managing attention deficit/attention deficit hyperactivity disorder (ADD/ADHD) in the acute psychiatric hospital setting.

Methods: We demonstrate the management of three patients with associated ADD/ADHD diagnosis in the hospital setting. This case series is followed by a review of the literature on the treatment of ADD/ADHD with particular focus on inpatient treatment.