Modelling of direct motor program learning in fast human arm motions

We propose and simulate a new paradigm for organization of motor control in fast and accurate human arm motions. We call the paradigm direct motor program learning since the control programs are learned directly without knowing or learning the dynamics of a controlled system.The idea is to approximate the dependence of the motor control programs on the vector of the task parameters rather than to use a model of the system dynamics. We apply iterative learning control and scattered data multivariate approximation techniques to achieve the goal. The advantage of the paradigm is that the control complexity depends neither on the order nor on the nonlinearity of the system dynamics.We simulate the direct motor program learning paradigm in the task of point-to-point control of fast planar human arm motions. Simulation takes into account nonlinear arm dynamics, muscle force dynamics, delay in low-level reflex feedback, time dependence of the feedback gains and coactivation of antagonist muscles. Despite highly nonlinear time-variant dynamics of the controlled system, reasonably good motion precision is obtained over a wide range of the task parameters (initial and final positions of the arm). The simulation results demonstrate that the paradigm is indeed viable and could be considered as a possible explanation for the organization of motor control of fast motions.     

Generation and Characterization of Human Interferon-beta Neutralizing Humanized Antibody

Russian Journal of Bioorganic Chemistry - Humanization of antibodies for the development of novel therapeutic agents with low immunogenicity remains a topical problem in modern science. In the...     

Development of the Bispecific Antibody in Fab-scFv Format Based on an Antibody to Human Interferon Beta-1 and Antibody to HER2 Receptor

Russian Journal of Bioorganic Chemistry - The development of new therapies for malignant tumors is an urgent task. Currently, the humanized antibody trastuzumab is considered the “gold...     

Bacterial iron detoxification at the molecular level

Iron is an essential micronutrient, and, in the case of bacteria, its availability is commonly a growth-limiting factor. However, correct functioning of cells requires that the labile pool of chelatable “free” iron be tightly regulated. Correct metalation of proteins requiring iron as a cofactor demands that such a readily accessible source of iron exist, but overaccumulation results in an oxidative burden that, if unchecked, would lead to cell death. The toxicity of iron stems from its potential to catalyze formation of reactive oxygen species that, in addition to causing damage to biological molecules, can also lead to the formation of reactive nitrogen species. To avoid iron-mediated oxidative stress, bacteria utilize iron-dependent global regulators to sense the iron status of the cell and regulate the expression of proteins involved in the acquisition, storage, and efflux of iron accordingly. Here, we survey the current understanding of the structure and mechanism of the important members of each of these classes of protein. Diversity in the details of iron homeostasis mechanisms reflect the differing nutritional stresses resulting from the wide variety of ecological niches that bacteria inhabit. However, in this review, we seek to highlight the similarities of iron homeostasis between different bacteria, while acknowledging important variations. In this way, we hope to illustrate how bacteria have evolved common approaches to overcome the dual problems of the insolubility and potential toxicity of iron.     

The Emerging Role of p38 Mitogen-Activated Protein Kinase in Multiple Sclerosis and Its Models

Multiple sclerosis (MS), the most common disabling neurologic disease of young adults, is considered a classical T cell-mediated disease and is characterized by demyelination, axonal damage, and progressive neurological dysfunction. The currently available disease-modifying therapies are limited in their efficacy, and improved understanding of new pathways contributing to disease pathogenesis could reveal additional novel therapeutic targets. The p38 mitogen-activated protein kinase (MAPK) signaling pathway is known to be triggered by stress stimuli and to contribute to inflammatory responses. Importantly, a number of recent studies have identified this signaling pathway as a central player in MS and its principal animal model, experimental allergic encephalomyelitis. Here, we review the evidence from mouse and human studies supporting the role of p38 MAPK in regulating key immunopathogenic mechanisms underlying autoimmune inflammatory disease of the central nervous system and the potential of targeting this pathway as a disease-modifying therapy in MS.     

Production of humanized F(ab’)<Subscript>2</Subscript> fragment of rabies blocking antibodies in <Emphasis Type="Italic">Pichia pastoris</Emphasis> yeast

The yeast strain Pichia pastoris, a producer of humanized F(ab’)₂ fragments of rabies-blocking antibodies, has been obtained. Human chaperone BiP coexpression caused a twofold increase of the immunoglobulins secretion level. The use of Fos and Jun zippers in the composition of heavy chains facilitated the dimerization of F(ab’)₂ fragments of the shared pool of secreted immunoglobulins up to 75%.     

Determination of cyclosporin A in 20% ethanol by a magnetic beads-based immunofluorescence assay

A rapid magnetic beads-based immunoassay for the immunodepressant drug cyclosporin A (CsA) has been developed. The method allows CsA determination in medium with a higher content of ethanol compared to conventional immunochemical techniques due to increased antibody stability. Monitoring of the drug in ethanol extracts from patient's whole blood without many-fold dilution with aqueous buffer is possible. The assay has adequate specificity and sensitivity for CsA to be suitable for the routine monitoring of therapy.     

Reactive oxygen species derived from the mitochondrial respiratory chain are not responsible for the basal levels of oxidative base modifications observed in nuclear DNA of Mammalian cells

The mitochondrial electron transport chain (ETC) is the most important source of reactive oxygen species (ROS) in mammalian cells. To assess its relevance to the endogenous generation of oxidative DNA damage in the nucleus, we have compared the background (steady-state) levels of oxidative DNA base modifications sensitive to the repair glycosylase Fpg (mostly 7,8-dihydro-8-oxoguanine) in wild-type HeLa cells and HeLa rho0 cells. The latter are depleted of mitochondrial DNA and therefore are unable to produce ROS in the ETC. Although the levels of ROS measured by flow cytometry and redox-sensitive probes in rho0 cells were only 10-15% those of wild-type cells, steady-state levels of oxidative DNA base modifications were the same as in wild-type cells. Mitochondrial generation of ROS was then stimulated in HeLa wild-type cells using inhibitors interfering with the ETC. Although mitochondrial ROS production was raised up to 6-fold, none of the substances nor their combinations induced additional oxidative base modifications in the nuclear DNA. This was also true for glutathione-depleted cells. The results indicate that the contribution of mitochondria to the endogenously generated background levels of oxidative damage in the nuclear DNA is negligible.     

A beneficial role of cardiac P2X4 receptors in heart failure: rescue of the calsequestrin overexpression model of cardiomyopathy

The P2X4 purinergic receptor (P2X4R) is a ligand-gated ion channel. Its activation by extracellular ATP results in Ca2+ influx. Transgenic cardiac overexpression of the human P2X4 receptor showed an in vitro phenotype of enhanced basal contractility. The objective here was to determine the in vivo cardiac physiological role of this receptor. Specifically, we tested the hypothesis that this receptor plays an important role in modulating heart failure progression. Transgenic cardiac overexpression of canine calsequestrin (CSQ) showed hypertrophy, heart failure, and premature death. Crossing the P2X4R mouse with the CSQ mouse more than doubled the lifespan (182 +/- 91 days for the binary CSQ/P2X4R mouse, n = 35) of the CSQ mouse (71.3 +/- 25.4 days, n = 50, P < 0.0001). The prolonged survival in the binary CSQ/P2X4R mouse was associated with an improved left ventricular weight-to-body weight ratio and a restored beta-adrenergic responsiveness. The beneficial phenotype of the binary mouse was not associated with any downregulation of the CSQ level but correlated with improved left ventricular developed pressure and +/-dP/dt. The enhanced cardiac performance was manifested in young binary animals and persisted in older animals. The increased contractility likely underlies the survival benefit from P2X4 receptor overexpression. An increased expression or activation of this receptor may represent a new approach in the therapy of heart failure.