The distinctive mechanical and structural signatures of residual force enhancement in myofibers.

In muscle, titin proteins connect myofilaments together and are thought to be critical for contraction, especially during residual force enhancement (RFE) when steady-state force is elevated after an active stretch. We investigated titin's function during contraction using small-angle X-ray diffraction to track structural changes before and after 50% titin cleavage and in the RFE-deficient, titin mutant. We report that the RFE state is structurally distinct from pure isometric contractions, with increased thick filament strain and decreased lattice spacing, most likely caused by elevated titin-based forces.

Mavacamten facilitates myosin head ON-to-OFF transitions and shortens thin filament length in relaxed skeletal muscle.

The first-in-its-class cardiac drug mavacamten reduces the proportion of so-called ON-state myosin heads in relaxed sarcomeres, altering contraction performance. However, mavacamten is not completely specific to cardiac myosin and can also affect skeletal muscle myosin, an important consideration since mavacamten is administered orally and so will also be present in skeletal tissue. Here, we studied the effect of mavacamten on skeletal muscle structure using small-angle X-ray diffraction.

Titin governs myocardial passive stiffness with major support from microtubules and actin and the extracellular matrix.

Myocardial passive stiffness is crucial for the heart's pump function and is determined by mechanical elements, including the extracellular matrix and cytoskeletal filaments; however, their individual contributions are controversially discussed and difficult to quantify. In this study, we targeted the cytoskeletal filaments in a mouse model, which enables the specific, acute and complete cleavage of the sarcomeric titin springs. We show in vitro that each cytoskeletal filament's stiffness contribution varies depending on whether the elastic or the viscous forces are considered and on strain level.

Fast myosin binding protein C knockout in skeletal muscle alters length-dependent activation and myofilament structure.

In striated muscle, the sarcomeric protein myosin-binding protein-C (MyBP-C) is bound to the myosin thick filament and is predicted to stabilize myosin heads in a docked position against the thick filament, which limits crossbridge formation. Here, we use the homozygous Mybpc2 knockout (C2) mouse line to remove the fast-isoform MyBP-C from fast skeletal muscle and then conduct mechanical functional studies in parallel with small-angle X-ray diffraction to evaluate the myofilament structure. We report that C2 fibers present deficits in force production and calcium sensitivity.

Remodeling of skeletal muscle myosin metabolic states in hibernating mammals.

Hibernation is a period of metabolic suppression utilized by many small and large mammal species to survive during winter periods. As the underlying cellular and molecular mechanisms remain incompletely understood, our study aimed to determine whether skeletal muscle myosin and its metabolic efficiency undergo alterations during hibernation to optimize energy utilization. We isolated muscle fibers from small hibernators, and and larger hibernators, and .

Myosin-binding protein C regulates the sarcomere lattice and stabilizes the OFF states of myosin heads.

Muscle contraction is produced via the interaction of myofilaments and is regulated so that muscle performance matches demand. Myosin-binding protein C (MyBP-C) is a long and flexible protein that is tightly bound to the thick filament at its C-terminal end (MyBP-C), but may be loosely bound at its middle- and N-terminal end (MyBP-C) to myosin heads and/or the thin filament. MyBP-C is thought to control muscle contraction via the regulation of myosin motors, as mutations lead to debilitating disease.

Titin-based force regulates cardiac myofilament structures mediating length-dependent activation.

The Frank-Starling law states that the heart's stroke volume increases with greater preload due to increased venous return, allowing the heart to adapt to varying circulatory demands. Molecularly, increasing preload increases sarcomere length (SL), which alters sarcomere structures that are correlated to increased calcium sensitivity upon activation. The titin protein, spanning the half-sarcomere, acts as a spring in the I-band, applying a SL-dependent force suggested to pull against and alter myofilaments in a way that supports the Frank-Starling effect.

Remodelling of Skeletal Muscle Myosin Metabolic States in Hibernating Mammals.

Hibernation is a period of metabolic suppression utilized by many small and large mammal species to survive during winter periods. As the underlying cellular and molecular mechanisms remain incompletely understood, our study aimed to determine whether skeletal muscle myosin and its metabolic efficiency undergo alterations during hibernation to optimize energy utilization. We isolated muscle fibers from small hibernators, Ictidomys tridecemlineatus and Eliomys quercinus and larger hibernators, Ursus arctos and Ursus americanus.

Fast myosin binding protein C knockout in skeletal muscle alters length-dependent activation and myofilament structure.

In striated muscle, some sarcomere proteins regulate crossbridge cycling by varying the propensity of myosin heads to interact with actin. Myosin-binding protein C (MyBP-C) is bound to the myosin thick filament and is predicted to interact and stabilize myosin heads in a docked position against the thick filament and limit crossbridge formation, the so-called OFF state. Via an unknown mechanism, MyBP-C is thought to release heads into the so-called ON state, where they are more likely to form crossbridges.

Myosin-binding protein C forms C-links and stabilizes OFF states of myosin.

Contraction force in muscle is produced by the interaction of myosin motors in the thick filaments and actin in the thin filaments and is fine-tuned by other proteins such as myosin-binding protein C (MyBP-C). One form of control is through the regulation of myosin heads between an ON and OFF state in passive sarcomeres, which leads to their ability or inability to interact with the thin filaments during contraction, respectively. MyBP-C is a flexible and long protein that is tightly bound to the thick filament at its C-terminal end but may be loosely bound at its middle- and N-terminal end (MyBP-C).

Predominant myosin superrelaxed state in canine myocardium with naturally occurring dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is a naturally occurring heart failure condition in humans and dogs, notably characterized by a reduced contractility and ejection fraction. As the identification of its underlying cellular and molecular mechanisms remain incomplete, the aim of the present study was to assess whether the molecular motor myosin and its known relaxed conformational states are altered in DCM. For that, we dissected and skinned thin cardiac strips from left ventricle obtained from six DCM Doberman Pinschers and six nonfailing (NF) controls.

Effectiveness of rehabilitation for working-age patients after a total hip arthroplasty: a comparison of usual care between the Netherlands and Germany.

Background: Postoperative rehabilitation after primary total hip arthroplasty (p-THA) differs between the Netherlands and Germany. Aim is to compare clinical effectiveness and to get a first impression of cost effectiveness of Dutch versus German usual care after p-THA.

Methods: A transnational prospective controlled observational trial.

The distinctive mechanical and structural signatures of residual force enhancement in myofibers.

In muscle, titin proteins connect myofilaments together and are thought to be critical for contraction, especially during residual force enhancement (RFE) when force is elevated after an active stretch. We investigated titin's function during contraction using small-angle X-ray diffraction to track structural changes before and after 50% titin cleavage and in the RFE-deficient, titin mutant. We report that the RFE state is structurally distinct from pure isometric contractions, with increased thick filament strain and decreased lattice spacing, most likely caused by elevated titin-based forces.

[Need for Action and Research in Psychosomatic and Orthopaedic Rehabilitation from the Point of View of Rehabilitants and Individuals who work in Rehabilitative Care].

Purpose: The aim of this study was to assess the need for practical action and research in psychosomatic and orthopaedic rehabilitation from the perspective of rehabilitants and individuals who work in rehabilitative care.

Methods: The project was divided into an identification and a prioritization phase. In the identification phase, 3872 former rehabilitants, 235 employees from three rehabilitation clinics and 31 employees of the German Pension Insurance Oldenburg-Bremen (DRV OL-HB) were invited to participate in a written survey.

Impact of Cancer Care Regionalization on Patient Volume.

Background: Cancer centers are regionalizing care to expand patient access, but the effects on patient volume are unknown. This study aimed to compare patient volumes before and after the establishment of head and neck regional care centers (HNRCCs).

Methods: This study analyzed 35,394 unique new patient visits at MD Anderson Cancer Center (MDACC) before and after the creation of HNRCCs.

Titin force in muscle cells alters lattice order, thick and thin filament protein formation.

Skeletal muscle force production is increased at longer compared to shorter muscle lengths because of length-dependent priming of thick filament proteins in the contractile unit before contraction. Using small-angle X-ray diffraction in combination with a mouse model that specifically cleaves the stretch-sensitive titin protein, we found that titin cleavage diminished the length-dependent priming of the thick filament. Strikingly, a titin-sensitive, length-dependent priming was also present in thin filaments, which seems only possible via bridge proteins between thick and thin filaments in resting muscle, potentially myosin-binding protein C.

Factors predicting pharyngocutaneous fistula in patients after salvage laryngectomy for laryngeal malignancy - A multicenter collaborative cohort study.

Objectives: Pharyngocutaneous fistula (PCF) is a major morbidity of salvage total laryngectomy (TL). Understanding the factors predicting PCF is fundamental to managing laryngeal cancer. We aim to assess factors associated with PCF following salvage TL in a multicenter, international retrospective cohort study of academic centers in the US and Canada.

[Occupational and Health Strains of Pensioners with Reduced Earning Capacity Due to Mental or Physical Illnesses - Implications for the Health Care System].

Objective: Demographic changes with an increasing number of people receiving pensions and a decreasing number of working people paying into the pension system represent major challenges for the German social security system. In particular, it is important to support people to continue working so that there is no (premature) reduction in their earning capacity and pensioners with reduced earning capacity (disability pensioners) should be helped to return to gainful employment. The aim of this study was to investigate the differing needs of two kinds of disability pensioners, namely those with mental illness and those who were physically ill.

Human NLRP1 is a sensor of pathogenic coronavirus 3CL proteases in lung epithelial cells.

Inflammation observed in SARS-CoV-2-infected patients suggests that inflammasomes, proinflammatory intracellular complexes, regulate various steps of infection. Lung epithelial cells express inflammasome-forming sensors and constitute the primary entry door of SARS-CoV-2. Here, we describe that the NLRP1 inflammasome detects SARS-CoV-2 infection in human lung epithelial cells.

Functional control of a 0.5 MDa TET aminopeptidase by a flexible loop revealed by MAS NMR.

Large oligomeric enzymes control a myriad of cellular processes, from protein synthesis and degradation to metabolism. The 0.5 MDa large TET2 aminopeptidase, a prototypical protease important for cellular homeostasis, degrades peptides within a ca.

Receptive and expressive vocabulary development in children learning English as an additional language: Converging evidence from multiple datasets.

Children learning English as an additional language (EAL) are a diverse and growing group of pupils in England's schools. Relative to their monolingual (ML) peers, these children tend to show lower receptive and expressive vocabulary knowledge in English, although interpretation of findings is limited by small and heterogeneous samples. In an effort to increase representativeness and power, the present study combined published and unpublished datasets from six cross-sectional and four longitudinal studies investigating the vocabulary development of 434 EAL learners and 342 ML peers (age range: 4;9-11;5) in 42 primary schools.