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1.
Digit Health ; 9: 20552076231169826, 2023.
Article in English | MEDLINE | ID: mdl-37113255

ABSTRACT

Introduction: Ensuring that the health data infrastructure and governance permits an efficient secondary use of data for research is a policy priority for many countries. Switzerland is no exception and many initiatives have been launched to improve its health data landscape. The country now stands at an important crossroad, debating the right way forward. We aimed to explore which specific elements of data governance can facilitate - from ethico-legal and socio-cultural perspectives - the sharing and reuse of data for research purposes in Switzerland. Methods: A modified Delphi methodology was used to collect and structure input from a panel of experts via successive rounds of mediated interaction on the topic of health data governance in Switzerland. Results: First, we suggested techniques to facilitate data sharing practices, especially when data are shared between researchers or from healthcare institutions to researchers. Second, we identified ways to improve the interaction between data protection law and the reuse of data for research, and the ways of implementing informed consent in this context. Third, we put forth ideas on policy changes, such as the steps necessary to improve coordination between different actors of the data landscape and to win the defensive and risk-adverse attitudes widespread when it comes to health data. Conclusions: After having engaged with these topics, we highlighted the importance of focusing on non-technical aspects to improve the data-readiness of a country (e.g., attitudes of stakeholders involved) and of having a pro-active debate between the different institutional actors, ethico-legal experts and society at large.

2.
Macromol Biosci ; 23(8): e2200437, 2023 08.
Article in English | MEDLINE | ID: mdl-36459417

ABSTRACT

Imitation of cellular processes in cell-like compartments is a current research focus in synthetic biology. Here, a method is introduced for assembling an artificial cytoskeleton in a synthetic cell model system based on a poly(N-isopropyl acrylamide) (PNIPAM) composite material. Toward this end, a PNIPAM-based composite material inside water-in-oil droplets that are stabilized with PNIPAM-functionalized and commercial fluorosurfactants is introduced. The temperature-mediated contraction/release behavior of the PNIPAM-based cytoskeleton is investigated. The reversibility of the PNIPAM transition is further examined in bulk and in droplets and it could be shown that hydrogel induced deformation could be used to controllably manipulate droplet-based synthetic cell motility upon temperature changes. It is envisioned that a combination of the presented artificial cytoskeleton with naturally occurring components might expand the bandwidth of the bottom-up synthetic biology.


Subject(s)
Artificial Cells , Hydrogels , Water , Temperature , Cytoskeleton
3.
Clin Pharmacol Ther ; 111(4): 857-866, 2022 04.
Article in English | MEDLINE | ID: mdl-35100444

ABSTRACT

Selecting the right dose is a significant challenge in designing clinical development programs, especially for slowly progressing diseases lacking predictive biomarkers of efficacy that may require long-term treatment to assess clinical benefit. Gantenerumab, a fully human monoclonal antibody (mAb) that binds to aggregated amyloid-beta, was tested in two 24-month phase III studies (NCT01224106, NCT02051608) in participants with prodromal and mild Alzheimer's disease (AD), respectively. Dosing in the first phase III study was suspended after a preplanned interim futility analysis in 2014. Subsequently, a dose-response relationship was observed in a subgroup of fast AD progressors that, together with contemporary aducanumab (another anti-amyloid-beta mAb) data, indicated higher doses may be needed for clinical efficacy. The gantenerumab phase III studies were therefore transformed into dose-finding, open-label extension (OLE) trials. Two exposure-response models were developed to support dose selection via simulations for the OLEs: a pharmacokinetics (PK)/PET (positron emission tomography) model describing amyloid removal using PET data from low-dose gantenerumab and high-dose aducanumab, and a PK/ARIA-E (amyloid-related imaging abnormalities-edema) model describing the occurrence of ARIA-E events leveraging an existing bapineuzumab model. Multiple regimens were designed to gradually up-titrate participants to the target dose of 1,200 mg gantenerumab every 4 weeks to mitigate the increased risk of ARIA-E events that may be associated with higher doses of anti-amyloid-beta antibodies. Favorable OLE data that matched well with model predictions supported the decision to continue the gantenerumab clinical development program and further apply model-based analytical techniques to optimize the design of new phase III studies.


Subject(s)
Alzheimer Disease , Alzheimer Disease/drug therapy , Amyloid beta-Peptides , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized , Clinical Trials, Phase III as Topic , Humans , Positron-Emission Tomography
4.
Nano Lett ; 22(3): 1145-1150, 2022 02 09.
Article in English | MEDLINE | ID: mdl-35089720

ABSTRACT

Molecular motors are pivotal for intracellular transport as well as cell motility and have great potential to be put to use outside cells. Here, we exploit engineered motor proteins in combination with self-assembly of actin filaments to actively pull lipid nanotubes from giant unilamellar vesicles (GUVs). In particular, actin filaments are bound to the outer GUV membrane and the GUVs are seeded on a heavy meromyosin-coated substrate. Upon addition of ATP, hollow lipid nanotubes with a length of tens of micrometer are pulled from single GUVs due to the motor activity. We employ the same mechanism to pull lipid nanotubes from different types of cells. We find that the length and number of nanotubes critically depends on the cell type, whereby suspension cells form bigger networks than adherent cells. This suggests that molecular machines can be used to exert forces on living cells to probe membrane-to-cortex attachment.


Subject(s)
Actomyosin , Nanotubes , Actin Cytoskeleton/metabolism , Actomyosin/chemistry , Actomyosin/metabolism , Lipids/chemistry , Nanotubes/chemistry , Unilamellar Liposomes/chemistry
5.
ACS Synth Biol ; 11(1): 366-382, 2022 01 21.
Article in English | MEDLINE | ID: mdl-34889607

ABSTRACT

By using electrostatic interactions as driving force to assemble vesicles, the droplet-stabilized method was recently applied to reconstitute and encapsulate proteins, or compartments, inside giant unilamellar vesicles (GUVs) to act as minimal synthetic cells. However, the droplet-stabilized approach exhibits low production efficiency associated with the troublesome release of the GUVs from the stabilized droplets, corresponding to a major hurdle for the droplet-stabilized approach. Herein, we report the use of pH as a potential trigger to self-assemble droplet-stabilized GUVs (dsGUVs) by either bulk or droplet-based microfluidics. Moreover, pH enables the generation of compartmentalized GUVs with flexibility and robustness. By co-encapsulating pH-sensitive small unilamellar vesicles (SUVs), negatively charged SUVs, and/or proteins, we show that acidification of the droplets efficiently produces dsGUVs while sequestrating the co-encapsulated material. Most importantly, the pH-mediated assembly of dsGUVs significantly improves the production efficiency of free-standing GUVs (i.e., released from the stabilizing-droplets) compared to its previous implementation.


Subject(s)
Artificial Cells , Hydrogen-Ion Concentration , Microfluidics , Polymers , Unilamellar Liposomes/metabolism
6.
Adv Biosyst ; 4(9): e2000102, 2020 09.
Article in English | MEDLINE | ID: mdl-32696544

ABSTRACT

External control and precise manipulation is key for the bottom-up engineering of complex synthetic cells. Minimal actomyosin networks have been reconstituted into synthetic cells; however, their light-triggered symmetry breaking contraction has not yet been demonstrated. Here, light-activated directional contractility of a minimal synthetic actomyosin network inside microfluidic cell-sized compartments is engineered. Actin filaments, heavy-meromyosin-coated beads, and caged ATP are co-encapsulated into water-in-oil droplets. ATP is released upon illumination, leading to a myosin-generated force which results in a motion of the beads along the filaments and hence a contraction of the network. Symmetry breaking is achieved using DNA nanotechnology to establish a link between the network and the compartment periphery. It is demonstrated that the DNA-linked actin filaments contract to one side of the compartment forming actin asters and quantify the dynamics of this process. This work exemplifies that an engineering approach to bottom-up synthetic biology, combining biological and artificial elements, can circumvent challenges related to active multi-component systems and thereby greatly enrich the complexity of synthetic cellular systems.


Subject(s)
Actin Cytoskeleton , Actomyosin , Nanotechnology/methods , Synthetic Biology/methods , Actin Cytoskeleton/chemistry , Actin Cytoskeleton/metabolism , Actomyosin/chemistry , Actomyosin/metabolism , DNA/chemistry , DNA/metabolism
7.
Front Physiol ; 8: 367, 2017.
Article in English | MEDLINE | ID: mdl-28620318

ABSTRACT

The in vitro motility assay (IVMA) is a technique that enables the measurement of the interaction between actin and myosin providing a relatively simple model to understand the mechanical muscle function. For actin-myosin IVMA, myosin is immobilized in a measurement chamber, where it converts chemical energy provided by ATP hydrolysis into mechanical energy. The result is the movement of fluorescently labeled actin filaments that can be recorded microscopically and analyzed quantitatively. Resulting sliding speeds and patterns help to characterize the underlying actin-myosin interaction that can be affected by different factors such as mutations or active compounds. Additionally, modulatory actions of the regulatory proteins tropomyosin and troponin in the presence of calcium on actin-myosin interaction can be studied with the IVMA. Zebrafish is considered a suitable model organism for cardiovascular and skeletal muscle research. In this context, straightforward protocols for the isolation and use of zebrafish muscle proteins in the IVMA would provide a useful tool in molecular studies. Currently, there are no protocols available for the mentioned purpose. Therefore, we developed fast and easy protocols for characterization of zebrafish proteins in the IVMA. Our protocols enable the interested researcher to (i) isolate actin from zebrafish skeletal muscle and (ii) extract functionally intact myosin from cardiac and skeletal muscle of individual adult zebrafish. Zebrafish tail muscle actin is isolated after acetone powder preparation, polymerized, and labeled with Rhodamine-Phalloidin. Myosin from ventricles of adult zebrafish is extracted directly into IVMA flow-cells. The same extraction protocol is applicable for comparably small tissue pieces as from zebrafish tail, mouse and frog muscle. After addition of the fluorescently labeled F-actin from zebrafish-or other origin-and ATP, sliding movement can be visualized using a fluorescence microscope and an intensified CCD camera. Taken together, we introduce a method for functional analysis in zebrafish cardiac and skeletal muscle research to study mutations at the molecular level of thick or thin filament proteins. Additionally, preliminary data indicate the usefulness of the presented method to perform the IVMA with myosin extracted from muscles of other animal models.

8.
Clin Pharmacokinet ; 55(7): 823-832, 2016 07.
Article in English | MEDLINE | ID: mdl-26715215

ABSTRACT

BACKGROUND AND OBJECTIVES: We propose a strategy for studying ethnopharmacology by conducting sequential physiologically based pharmacokinetic (PBPK) prediction (a 'bottom-up' approach) and population pharmacokinetic (popPK) confirmation (a 'top-down' approach), or in reverse order, depending on whether the purpose is ethnic effect assessment for a new molecular entity under development or a tool for ethnic sensitivity prediction for a given pathway. The strategy is exemplified with bitopertin. METHODS: A PBPK model was built using Simcyp(®) to simulate the pharmacokinetics of bitopertin and to predict the ethnic sensitivity in clearance, given pharmacokinetic data in just one ethnicity. Subsequently, a popPK model was built using NONMEM(®) to assess the effect of ethnicity on clearance, using human data from multiple ethnic groups. A comparison was made to confirm the PBPK-based ethnic sensitivity prediction, using the results of the popPK analysis. RESULTS: PBPK modelling predicted that the bitopertin geometric mean clearance values after 20 mg oral administration in Caucasians would be 1.32-fold and 1.27-fold higher than the values in Chinese and Japanese, respectively. The ratios of typical clearance in Caucasians to the values in Chinese and Japanese estimated by popPK analysis were 1.20 and 1.17, respectively. The popPK analysis results were similar to the PBPK modelling results. CONCLUSION: As a general framework, we propose that PBPK modelling should be considered to predict ethnic sensitivity of pharmacokinetics prior to any human data and/or with data in only one ethnicity. In some cases, this will be sufficient to guide initial dose selection in different ethnicities. After clinical trials in different ethnicities, popPK analysis can be used to confirm ethnic differences and to support dose justification and labelling. PBPK modelling prediction and popPK analysis confirmation can complement each other to assess ethnic differences in pharmacokinetics at different drug development stages.


Subject(s)
Asian People , Models, Biological , Piperazines/pharmacokinetics , Sulfones/pharmacokinetics , White People , Adolescent , Adult , Body Mass Index , Computer Simulation , Dose-Response Relationship, Drug , Female , Humans , Male , Metabolic Clearance Rate , Middle Aged , Young Adult
9.
Eur J Clin Pharmacol ; 71(5): 617-24, 2015 May.
Article in English | MEDLINE | ID: mdl-25801493

ABSTRACT

PURPOSE: The purpose of this study is to evaluate the ethnicity-specific population models in the SimCYP Simulator® for prediction of omeprazole clearance with attention to differences in the CYP2C19 metabolic pathway. METHODS: The SimCYP® models incorporating Caucasian, Chinese, and Japanese population-specific demographic, physiological, and enzyme data were applied to simulate omeprazole pharmacokinetics. Published pharmacokinetic data of omeprazole after intravenous or oral administration in Caucasian, Chinese, and Japanese were used for the evaluation. RESULTS: Following oral administration, the ratio of the predicted to observed geometric mean of omeprazole clearance in Caucasian extensive metabolizers (EMs) was 0.88. The ratios in Chinese EMs were 1.16 and 0.99 after intravenous and oral administration, respectively. The ratios in Japanese EMs were 0.88 and 0.71 after intravenous and oral administration, respectively. Significant differences (2-fold) in the observed oral clearance of omeprazole were identified between Caucasian and Asian (Chinese and Japanese) EMs while the observed oral and intravenous clearances of omeprazole were similar between Chinese and Japanese EMs. Physiologically based pharmacokinetics (PBPK) models within SimCYP accurately predicted the difference in the observed oral clearance between Caucasian and Chinese EMs but overpredicted the difference between Caucasians and Japanese EMs due to under-prediction of oral clearance in Japanese EMs. CONCLUSIONS: The PBPK model within SimCYP adequately predicted omeprazole clearance in Caucasian, Chinese, and Japanese EMs and the 2-fold differences in clearance of omeprazole between Caucasian and Asian EMs. This may lead to early identification of ethnic sensitivity in clearance and the need for different dosing regimens in a specific ethnic group for substrates of CYP2C19 which can support the rational design of bridging clinical trials.


Subject(s)
Cytochrome P-450 CYP2C19/metabolism , Gastrointestinal Tract/physiology , Liver/physiology , Models, Biological , Omeprazole/pharmacokinetics , Proton Pump Inhibitors/pharmacokinetics , Administration, Oral , Asian People , Computer Simulation , Gastrointestinal Tract/enzymology , Humans , Injections, Intravenous , Liver/enzymology , Metabolic Clearance Rate , Omeprazole/administration & dosage , Omeprazole/blood , Predictive Value of Tests , Proton Pump Inhibitors/administration & dosage , Proton Pump Inhibitors/blood , White People
10.
Neuromuscul Disord ; 24(7): 596-603, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24880993

ABSTRACT

Duchenne muscular dystrophy is an inherited degenerative muscle disease with progressive weakness of skeletal and cardiac muscle. Disturbed calcium homeostasis and signalling pathways result in degeneration/regeneration cycles with fibrotic remodelling of muscle tissue, sustained by chronic inflammation. In addition to altered microarchitecture, regeneration in dystrophic muscle fibres is often only classified by centrally located nuclei but correlation of the regeneration process to nuclear volumes, myosin amounts, architecture and functional quality are missing, in particular in old muscles where the regenerative capacity is exhausted. Such information could yield novel regeneration-to-function biomarkers. Here we used second harmonic generation and multi photon fluorescence microscopy in intact single muscle fibres from wild-type, dystrophic mdx and transgenic mdx mice expressing an Δex 17-48 mini-dystrophin to determine the percentage of centronucleated fibres and nucleus-to-myosin volume ratio as a function of age. Based on this ratio we define a 'biomotoric efficiency' as an optical measure for fibre maturation, which is close to unity in adult wild-type and mini-dystrophin fibres, but smaller in very young and old mdx mice as a result of ongoing cell maturation (young) and regeneration (aged). With these parameters it is possible to provide a quantitative measure about muscle fibre regeneration.


Subject(s)
Image Interpretation, Computer-Assisted/methods , Microscopy, Fluorescence, Multiphoton/methods , Muscle Fibers, Skeletal/pathology , Muscle, Skeletal/physiopathology , Muscular Dystrophy, Animal/pathology , Regeneration , Age Factors , Animals , Blotting, Western , Imaging, Three-Dimensional , Mice, Inbred C57BL , Mice, Inbred mdx , Mice, Transgenic , Muscle Fibers, Skeletal/physiology , Muscle, Skeletal/pathology , Muscular Dystrophy, Animal/physiopathology , Ubiquitin/metabolism
11.
Am J Respir Cell Mol Biol ; 50(6): 1096-106, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24400695

ABSTRACT

Critical illness myopathies in patients with sepsis or sustained mechanical ventilation prolong intensive care treatment and threaten both patients and health budgets; no specific therapy is available. Underlying pathophysiological mechanisms are still patchy. We characterized IL-1α action on muscle performance in "skinned" muscle fibers using force transducers and confocal Ca(2+) fluorescence microscopy for force/Ca(2+) transients and Ca(2+) sparks. Association of IL-1α with sarcoplasmic reticulum (SR) release channel, ryanodine receptor (RyR) 1, was investigated with coimmunoprecipitation and confocal immunofluorescence colocalization. Membrane integrity was studied in single, intact fibers challenged with IL-1α. IL-1α reversibly stabilized Mg(2+) inhibition of Ca(2+) release. Low Mg(2+)-induced force and Ca(2+) transients were reversibly abolished by IL-1α. At normal Mg(2+), IL-1α reversibly increased caffeine-induced force and Ca(2+) transients. IL-1α reduced SR Ca(2+) leak via RyR1, as judged by (1) increased SR Ca(2+) retention, (2) increased IL-1α force transients being reproduced by 25 µM tetracaine, and (3) reduced Ca(2+) spark frequencies by IL-1α or tetracaine. Coimmunoprecipitation confirmed RyR1/IL-1 association. RyR1/IL-1 immunofluorescence patterns perfectly colocalized. Long-term, 8-hour IL-1α challenge of intact muscle fibers compromised membrane integrity in approximately 50% of fibers, and confirmed intracellular IL-1α deposition. IL-1α exerts a novel, specific, and reversible interaction mechanism with the skeletal muscle RyR1 macromolecular release complex without the need to act via its membrane IL-1 receptor, as IL-1R membrane expression levels were not detectable in Western blots or immunostaining of single fibers. We present a potential explanation of how the inflammatory mediator, IL-1α, may contribute to muscle weakness in critical illness.


Subject(s)
Interleukin-1/metabolism , Muscle Fibers, Skeletal/metabolism , Muscular Diseases/metabolism , Ryanodine Receptor Calcium Release Channel/metabolism , Animals , Calcium/metabolism , Cell Membrane/metabolism , Critical Illness , Magnesium/metabolism , Mice , Mice, Inbred C57BL , Muscle Weakness/metabolism , Protein Binding/physiology , Sarcoplasmic Reticulum/metabolism
12.
J Cell Mol Med ; 18(1): 69-79, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24251822

ABSTRACT

Cachexia presents with ongoing muscle wasting, altering quality of life in cancer patients. Cachexia is a limiting prognostic factor for patient survival and health care costs. Although animal models and human trials have shown mechanisms of motorprotein proteolysis, not much is known about intrinsic changes of muscle functionality in cancer patients suffering from muscle cachexia, and deeper insights into cachexia pathology in humans are needed. To address this question, rectus abdominis muscle samples were collected from several surgical control, non-cachectic and cachectic cancer patients and processed for skinned fibre biomechanics, molecular in vitro motility assays, myosin isoform protein compositions and quantitative ubiquitin polymer protein analysis. In pre-cachectic and cachectic cancer patient samples, maximum force was significantly compromised compared with controls, but showed an unexpected increase in myofibrillar Ca(2+) sensitivity consistent with a shift from slow to fast myosin isoform expression seen in SDS-PAGE analysis and in vitro motility assays. Force deficit was specific for 'cancer', but not linked to presence of cachexia. Interestingly, quantitative ubiquitin immunoassays revealed no major changes in static ubiquitin polymer protein profiles, whether cachexia was present or not and were shown to mirror profiles in control patients. Our study on muscle function in cachectic patients shows that abdominal wall skeletal muscle in cancer cachexia shows signs of weakness that can be partially attributed to intrinsic changes to contractile motorprotein function. On protein levels, static ubiquitin polymeric distributions were unaltered, pointing towards evenly up-regulated ubiquitin protein turnover with respect to ubiquitin conjugation, proteasome degradation and de-ubiquitination.


Subject(s)
Abdominal Muscles/metabolism , Cachexia/metabolism , Colonic Neoplasms/metabolism , Myosins/physiology , Pancreatic Neoplasms/metabolism , Abdominal Muscles/pathology , Abdominal Muscles/physiopathology , Adult , Aged , Aged, 80 and over , Cachexia/etiology , Cachexia/physiopathology , Calcium/physiology , Colonic Neoplasms/complications , Colonic Neoplasms/physiopathology , Female , Humans , In Vitro Techniques , Male , Middle Aged , Muscle Contraction , Pancreatic Neoplasms/complications , Pancreatic Neoplasms/physiopathology , Protein Isoforms/metabolism , Single-Cell Analysis , Ubiquitin/metabolism
13.
Nucleic Acids Res ; 41(12): e124, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23625964

ABSTRACT

The emergence and future of mammalian synthetic biology depends on technologies for orchestrating and custom tailoring complementary gene expression and signaling processes in a predictable manner. Here, we demonstrate for the first time multi-chromatic expression control in mammalian cells by differentially inducing up to three genes in a single cell culture in response to light of different wavelengths. To this end, we developed an ultraviolet B (UVB)-inducible expression system by designing a UVB-responsive split transcription factor based on the Arabidopsis thaliana UVB receptor UVR8 and the WD40 domain of COP1. The system allowed high (up to 800-fold) UVB-induced gene expression in human, monkey, hamster and mouse cells. Based on a quantitative model, we determined critical system parameters. By combining this UVB-responsive system with blue and red light-inducible gene control technology, we demonstrate multi-chromatic multi-gene control by differentially expressing three genes in a single cell culture in mammalian cells, and we apply this system for the multi-chromatic control of angiogenic signaling processes. This portfolio of optogenetic tools enables the design and implementation of synthetic biological networks showing unmatched spatiotemporal precision for future research and biomedical applications.


Subject(s)
Gene Expression Regulation/radiation effects , Signal Transduction/radiation effects , Ultraviolet Rays , Animals , Arabidopsis Proteins/metabolism , CHO Cells , COS Cells , Cells, Cultured , Chlorocebus aethiops , Chromosomal Proteins, Non-Histone/metabolism , Cricetinae , Cricetulus , Humans , Mice , Neovascularization, Physiologic/genetics , Neovascularization, Physiologic/radiation effects , Tissue Engineering , Ubiquitin-Protein Ligases/metabolism
14.
J Pathol ; 229(3): 477-85, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23132094

ABSTRACT

Duchenne muscular dystrophy (DMD) is a common inherited muscle disease showing chronic inflammation and progressive muscle weakness. Absent dystrophin renders sarcolemma more Ca(2+) -permeable, disturbs signalling and triggers inflammation. Sustained degeneration/regeneration cycles render muscle cytoarchitecture susceptible to remodelling. Quantitative morphometry was introduced in living cells using second-harmonic generation (SHG) microscopy of myosin. As the time course of cellular remodelling is not known, we used SHG microscopy in mdx muscle fibres over a wide age range for three-dimensional (3D) rendering and detection of verniers and cosine angle sums (CASs). Wild-type (wt) and transgenic mini-dystrophin mice (MinD) were also studied. Vernier densities (VDs) declined in wt and MinD fibres until adulthood, while in mdx fibres, VDs remained significantly elevated during the life span. CAS values were close to unity in adult wt and MinD fibres, in agreement with tight regular myofibril orientation, while always smaller in mdx fibres. Using SHG 3D morphometry, we identified two types of altered ultrastructure: branched fibres and a novel, previously undetected 'chaotic' fibre type, both of which can be classified by distinct CAS and VD combinations. We present a novel model of tissue remodelling in dystrophic progression with age that involves the transition from normal to chaotic to branched fibres. Our model predicts a ~50% contribution of altered cytoarchitecture to progressive force loss with age. We also provide an improved automated image algorithm that is suitable for future ageing studies in human myopathies.


Subject(s)
Aging/physiology , Microscopy, Acoustic/methods , Muscle Fibers, Skeletal/pathology , Muscle, Skeletal/pathology , Muscular Dystrophy, Duchenne/pathology , Algorithms , Animals , Disease Models, Animal , Disease Progression , Image Interpretation, Computer-Assisted , Mice , Mice, Transgenic , Models, Biological , Muscle Fibers, Skeletal/metabolism , Muscle Fibers, Skeletal/ultrastructure , Muscle, Skeletal/physiopathology , Muscular Dystrophy, Duchenne/metabolism , Muscular Dystrophy, Duchenne/physiopathology , Myosins/metabolism , Myosins/ultrastructure , Regeneration
15.
J Cell Mol Med ; 16(12): 3028-36, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22970922

ABSTRACT

Progressive cardiomyopathy is a major cause of death in Duchenne muscular dystrophy (DMD) patients. Coupling between Ca(2+) handling and contractile properties in dystrophic hearts is poorly understood. It is also not clear whether developing cardiac failure is dominated by alterations in Ca(2+) pathways or more related to the contractile apparatus. We simultaneously recorded force and Ca(2+) transients in field-stimulated papillary muscles from young (10-14 weeks) wild-type (wt) and dystrophic mdx mice. Force amplitudes were fivefold reduced in mdx muscles despite only 30% reduction in fura-2 ratio amplitudes. This indicated mechanisms other than systolic Ca(2+) to additionally account for force decrements in mdx muscles. pCa-force relations revealed decreased mdx myofibrillar Ca(2+) sensitivity. 'In vitro' motility assays, studied in mdx hearts here for the first time, showed significantly slower sliding velocities. mdx MLC/MHC isoforms were not grossly altered. Dystrophic hearts showed echocardiography signs of early ventricular wall hypertrophy with a significantly enlarged end-diastolic diameter 'in vivo'. However, fractional shortening was still comparable to wt mice. Changes in the contractile apparatus satisfactorily explained force drop in mdx hearts. We give first evidence of early hypertrophy in mdx mice and possible mechanisms for already functional impairment of cardiac muscle in DMD.


Subject(s)
Heart/physiopathology , Muscular Dystrophy, Duchenne/physiopathology , Myocardial Contraction , Papillary Muscles/physiopathology , Animals , Calcium/metabolism , Cardiomegaly , Cardiomyopathies , Cells, Cultured , Echocardiography , Mice , Mice, Inbred mdx , Myocardium/cytology , Myocardium/metabolism
16.
Brain ; 135(Pt 2): 596-614, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22232595

ABSTRACT

Chronic stroke patients with heterogeneous lesions, but no direct damage to the primary sensorimotor cortex, are capable of longitudinally acquiring the ability to modulate sensorimotor rhythms using grasping imagery of the affected hand. Volitional modulation of neural activity can be used to drive grasping functions of the paralyzed hand through a brain-computer interface. The neural substrates underlying this skill are not known. Here, we investigated the impact of individual patient's lesion pathology on functional and structural network integrity related to this volitional skill. Magnetoencephalography data acquired throughout training was used to derive functional networks. Structural network models and local estimates of extralesional white matter microstructure were constructed using T(1)-weighted and diffusion-weighted magnetic resonance imaging data. We employed a graph theoretical approach to characterize emergent properties of distributed interactions between nodal brain regions of these networks. We report that interindividual variability in patients' lesions led to differential impairment of functional and structural network characteristics related to successful post-training sensorimotor rhythm modulation skill. Patients displaying greater magnetoencephalography global cost-efficiency, a measure of information integration within the distributed functional network, achieved greater levels of skill. Analysis of lesion damage to structural network connectivity revealed that the impact on nodal betweenness centrality of the ipsilesional primary motor cortex, a measure that characterizes the importance of a brain region for integrating visuomotor information between frontal and parietal cortical regions and related thalamic nuclei, correlated with skill. Edge betweenness centrality, an analogous measure, which assesses the role of specific white matter fibre pathways in network integration, showed a similar relationship between skill and a portion of the ipsilesional superior longitudinal fascicle connecting premotor and posterior parietal visuomotor regions known to be crucially involved in normal grasping behaviour. Finally, estimated white matter microstructure integrity in regions of the contralesional superior longitudinal fascicle adjacent to primary sensorimotor and posterior parietal cortex, as well as grey matter volume co-localized to these specific regions, positively correlated with sensorimotor rhythm modulation leading to successful brain-computer interface control. Thus, volitional modulation of ipsilesional neural activity leading to control of paralyzed hand grasping function through a brain-computer interface after longitudinal training relies on structural and functional connectivity in both ipsilesional and contralesional parietofrontal pathways involved in visuomotor information processing. Extant integrity of this structural network may serve as a future predictor of response to longitudinal therapeutic interventions geared towards training sensorimotor rhythms in the lesioned brain, secondarily improving grasping function through brain-computer interface applications.


Subject(s)
Frontal Lobe/physiopathology , Hand Strength/physiology , Imagination/physiology , Neurons/physiology , Parietal Lobe/physiopathology , Stroke/physiopathology , Adult , Aged , Brain Mapping , Female , Frontal Lobe/pathology , Humans , Male , Middle Aged , Nerve Fibers, Myelinated/pathology , Nerve Net/pathology , Nerve Net/physiopathology , Neurons/pathology , Parietal Lobe/pathology , Stroke/pathology
17.
Chemistry ; 17(5): 1507-18, 2011 Feb 01.
Article in English | MEDLINE | ID: mdl-21268153

ABSTRACT

Three-dimensional (3D) π-conjugated dendritic oligothiophenes up to a third generation have been functionalized with tris(decyloxy)phenylethynyl tails at the periphery. The first-generation compounds (3 T-p-Ph-C10 and 6 T-p-Ph-C10) were synthesized by palladium-catalyzed Sonogashira coupling reactions, whereas the higher generation products were synthesized by palladium-catalyzed Suzuki coupling reactions in a divergent approach. The optical and electrochemical properties were investigated by UV/Vis absorption, fluorescence spectroscopy, and cyclic voltammetry. The results revealed that the terminal tris(alkyloxy)phenylethynyl groups are conjugated to the branched oligothiophene core, yielding redshifted absorption and fluorescence spectra and reduced optical band gaps relative to the dendritic oligothiophene core. A structural study revealed a close relationship between the type of supramolecular organization and the size of the oligothiophene core. The first-generation compounds 3 T-p-Ph-C10 and 6 T-p-Ph-C10 displayed columnar phases in the bulk state, which was confirmed by two-dimensional wide-angle X-ray scattering (2D WAXS) measurements. The self-assembly into columnar stacks has mainly been attributed to phase separation between the rigid thiophene cores and the flexible side-chains assisted by minor π-stacking interactions between the conjugated dendritic oligothiophene units. The high-generation compounds, however, showed less ordered structures in the solid state.

18.
Psychophysiology ; 48(4): 578-82, 2011 Apr.
Article in English | MEDLINE | ID: mdl-20718931

ABSTRACT

A case of partial recovery after stroke and its associated brain reorganization in a chronic patient after combined brain computer interface (BCI) training and physiotherapy is presented. A multimodal neuroimaging approach based on fMRI and diffusion tensor imaging was used to investigate plasticity of the brain motor system in parallel with longitudinal clinical assessments. A convergent association between functional and structural data in the ipsilesional premotor areas was observed. As a proof of concept investigation, these results encourage further research on a specific role of BCI on brain plasticity and recovery after stroke.


Subject(s)
Physical Therapy Modalities , Recovery of Function , Stroke Rehabilitation , User-Computer Interface , Aged , Data Interpretation, Statistical , Diffusion Tensor Imaging , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Neural Pathways/physiology , Paralysis/etiology , Paralysis/rehabilitation , Pyramidal Tracts/physiology , Stroke/psychology
19.
Neurorehabil Neural Repair ; 24(7): 674-9, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20519741

ABSTRACT

BACKGROUND: There is no accepted and efficient rehabilitation strategy to reduce focal impairments for patients with chronic stroke who lack residual movements. METHODS: A 67-year-old hemiplegic patient with no active finger extension was trained with a brain-computer interface (BCI) combined with a specific daily life-oriented physiotherapy. The BCI used electrical brain activity (EEG) and magnetic brain activity (MEG) to drive an orthosis and a robot affixed to the patient's affected upper extremity, which enabled him to move the paralyzed arm and hand driven by voluntary modulation of micro-rhythm activity. In addition, the patient practiced goal-directed physiotherapy training. Over 1 year, he completed 3 training blocks. Arm motor function, gait capacities (using Fugl-Meyer Assessment, Wolf Motor Function Test, Modified Ashworth Scale, 10-m walk speed, and goal attainment score), and brain reorganization (functional MRI, MEG) were repeatedly assessed. RESULTS: The ability of hand and arm movements as well as speed and safety of gait improved significantly (mean 46.6%). Improvement of motor function was associated with increased micro-oscillations in the ipsilesional motor cortex. CONCLUSION: This proof-of-principle study suggests that the combination of BCI training with goal-directed, active physical therapy may improve the motor abilities of chronic stroke patients despite apparent initial paralysis.


Subject(s)
Computers/trends , Hemiplegia/rehabilitation , Physical Therapy Modalities/trends , Robotics/methods , Stroke Rehabilitation , User-Computer Interface , Aged , Chronic Disease , Hemiplegia/physiopathology , Humans , Male , Physical Therapy Modalities/instrumentation , Robotics/instrumentation , Robotics/trends , Stroke/physiopathology
20.
Eur J Clin Pharmacol ; 66(10): 1005-15, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20549497

ABSTRACT

OBJECTIVES: R483 is a thiazolidinedione peroxisome proliferator-activated receptor gamma (PPARγ) agonist with anti-diabetic properties and also a cytochrome P450 2C19 (CYP2C19) substrate. The aim of the clinical studies reported here was to investigate the influence of the CYP2C19 genotype on the pharmacokinetics (PK) of R483 in healthy subjects and in type 2 diabetes mellitus (T2DM) patients. METHODS: data came from two clinical studies, one including 58 Japanese and Caucasian healthy subjects and another including 93 Asian T2DM patients. All subjects received multiple doses of R483, 20 mg once daily for the healthy subjects and 12 mg once daily for the T2DM patients. Blood samples were taken up to 24 h after the last dose to determine plasma concentrations of R483 and its major metabolites. RESULTS: poor metabolizers (PMs; CYP2C19*2/*2 or *2/*3 or *3/*3) had a higher plasma exposure and a lower clearance of the parent drug than extensive metabolizers (EMs; CYP2C19*1/*1 or *1/*2 or *1/*3). The homozygous PM/EM ratio for the area under the plasma concentration-time curve (AUC(0-24)) [95% confidence interval] was 3.9 [2.7-5.7] for healthy subjects versus 2.0 [1.5-2.6] in T2DM patients. The heterozygous EMs were all T2DM patients, the PM/EM ratio for AUC(0-24) was 1.5 [1.2-1.8]. The dose-normalized exposure to R483 was 1.2- (for PMs) and 2.4-fold (for EMs) higher in T2DM patients than in healthy subjects. R483 was well tolerated in both studies. CONCLUSIONS: the plasma exposure to R483 was significantly higher in PMs than in EMs. R483 exhibits different PK in healthy subjects and T2DM patients, and the difference in exposure between EM and PM was less pronounced in T2DM patients than in healthy subjects. Factors such as diabetes condition and age may influence the metabolism of R483. This knowledge allowed for a realistic dose recommendation for poor metabolizer T2DM patients.


Subject(s)
Aryl Hydrocarbon Hydroxylases/genetics , Asian People/genetics , Diabetes Mellitus, Type 2/enzymology , Thiazolidinediones/pharmacokinetics , Thiophenes/pharmacokinetics , White People/genetics , Administration, Oral , Adult , Aged , Analysis of Variance , Area Under Curve , Aryl Hydrocarbon Hydroxylases/metabolism , Biological Availability , Blood Glucose/metabolism , Capsules , Chromatography, Liquid , Cytochrome P-450 CYP2C19 , Diabetes Mellitus, Type 2/genetics , Female , Genotype , Glycated Hemoglobin , Humans , Male , Middle Aged , Reference Values , Tablets , Tandem Mass Spectrometry , Thiazolidinediones/administration & dosage , Thiazolidinediones/adverse effects , Thiazolidinediones/blood , Thiophenes/administration & dosage , Thiophenes/adverse effects , Thiophenes/blood , Time Factors
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