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Korzynska A.,Nalecz Institute of Biocybernetics and Biomedical Engineering | Iwanowski M.,Warsaw University of Technology
Opto-electronics Review | Year: 2012

This paper describes the multistage morphological segmentation method (MSMA) for microscopic cell images. The proposed method enables us to study the cell behaviour by using a sequence of two types of microscopic images: bright field images and/or fluorescent images. The proposed method is based on two types of information: the cell texture coming from the bright field images and intensity of light emission, done by fluorescent markers. The method is dedicated to the image sequences segmentation and it is based on mathematical morphology methods supported by other image processing techniques. The method allows for detecting cells in image independently from a degree of their flattening and from presenting structures which produce the texture. It makes use of some synergic information from the fluorescent light emission image as the support information. The MSMA method has been applied to images acquired during the experiments on neural stem cells as well as to artificial images. In order to validate the method, two types of errors have been considered: the error of cell area detection and the error of cell position using artificial images as the "gold standard". © 2012 Versita Warsaw and Springer-Verlag Wien. Source


Piotrkiewicz M.,Nalecz Institute of Biocybernetics and Biomedical Engineering | Hausmanowa-Petrusewicz I.,Polish Academy of Sciences
Journal of Physiology | Year: 2011

Motor unit (MU) potentials were registered from 20 ALS patients and 13 age-matched control individuals during isometric constant force contractions of brachial biceps (BB). The registered signals were decomposed into single MU potential trains. The estimates of duration of the afterhyperpolarisation (AHP) in MNs, derived from the interspike interval variability, was compared between ALS patients (124 MNs) and control subjects (111 MNs) and no significant differences were encountered. However, the relationship between TI and age for patients appeared to be qualitatively different from that of the control group. The dependence of patients' AHPs on relative force deficit (RFD), which quantified muscle involvement, was more specific. For RFDs below 30%, the AHP estimate was significantly lower than control values and then increased thereafter with increasing RFDs. Moreover, firing rates of patients with the smallest RFDs were significantly higher while firing rates of patients with the greatest RFDs were significantly lower than control values. The AHP shortening in the early stages of muscle impairment is consistent with the decrease in firing threshold of 'fast' MNs found in spinal cord slices from neonatal SOD1 mice. The later elongation of the AHP may be caused by the higher vulnerability of 'fast' MNs to degeneration and by the influence of reinnervation. Our results are comparable to what has been observed in acute experiments in animal models, providing a bridge between animal and clinical research that may be relevant for identification of mechanism(s) underlying neurodegeneration in ALS. © 2011 The Authors. Journal compilation © 2011 The Physiological Society. Source


Golczewski T.,Nalecz Institute of Biocybernetics and Biomedical Engineering
Respiratory research | Year: 2012

Recent studies have showed that FEV1/FVC describing correspondence between the forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) depends significantly on age. However, the nature of this dependence is uncertain. The study aim is to analyze mathematically the relationship between FEV1 and FVC to find a cause of the FEV1/FVC dependence on age in healthy subjects. The relationship was examined for 1,120 males and 1,625 females--Polish (Caucasian) population, healthy, never-smoking, aged 18 - 85 years, who performed a technically adequate spirometry maneuver. Lung functions were measured using the LungTest1000 (MES, Poland) with maximal effort according to the ATS/ERS guidelines. A very strong, age-independent linear relationship between FEV1 and FVC was found in healthy individuals (the correlation coefficient r = 0.96). It can be described with the equation FEV1 = A x FVC + C, where A = 0.84 and C = -0.23 (-0.36) for females (males). As C is different from zero, FEV1/FVC depends on FVC because FEV1/FVC = A + C/FVC, in average. And thus, since FVC is significantly age-dependent, FEV1/FVC has to be also age-dependent because of the term C/FVC. In particular, the smaller the FVC value because of advanced age, the more significant the fall of FEV1/FVC. FEV1/FVC dependence on age in healthy individuals is of mathematical rather than biological nature. Due to the strong correlation between FEV1 and FVC in healthy subjects, the difference between patient's FEV1 and the FEV1 value expected for patient's FVC seems to be a more natural, age-independent description of the correspondence between patient's FEV1 and FVC. Source


Granicka L.H.,Nalecz Institute of Biocybernetics and Biomedical Engineering
Journal of Nanoscience and Nanotechnology | Year: 2014

This paper reviews the recent research and development of the systems of nano-thin layers coated cells for biomedical applications. Polyelectrolyte based nano-thin polymer coatings, due to their individual layered structure and functionalization ability, are a promising part of the systems involving cells for biological processes regulation. The purpose of the layer-by-layer coating technique application is to minimize capsule void volume and separate cells from the host immunological system eliminating immunosuppressive therapy during transplantation. The materials for polyelectrolyte shells and their modifications, followed by the techniques of forming polymer nano-thin coatings are briefly introduced. The enhanced properties of cell nanocoatings are then discussed, involving usability for encapsulation of live cells, immunological barrier, and coatings detection among others. The systems utilizing layer-by layer coatings without cell participation are briefly mentioned. Finally, the perspectives for the future are discussed in terms of limitations and application in biomedicine. Copyright © 2014 American Scientific Publishers All rights reserved. Source


Skubiszak L.,Nalecz Institute of Biocybernetics and Biomedical Engineering
International Journal of Molecular Sciences | Year: 2011

Computer simulation has uncovered the geometrical conditions under which the vertebrate striated muscle sarcomere can contract. First, all thick filaments should have identical structure, namely: three myosin cross-bridges, building a crown, should be aligned at angles of 0°, 120°, 180°, and the successive crowns and the two filament halves should be turned around 120°. Second, all thick filaments should act simultaneously. Third, coordination in action of the myosin cross-bridges should exist, namely: the three cross- bridges of a crown should act simultaneously and the cross-bridge crowns axially 43 and 14.333 nm apart should act, respectively, simultaneously and with a phase shift. Fifth, six thin filaments surrounding the thick filament should be turned around 180° to each other in each sarcomere half. Sixth, thin filaments should be oppositely oriented in relation to the sarcomere middle. Finally, the structure of each of the thin filaments should change in consequence of strong interaction with myosin heads, namely: the axial distance and the angular alignment between neighboring actin monomers should be, respectively, 2.867 nm and 168° instead of 2.75 nm and 166.15°. These conditions ensure the stereo-specific interaction between actin and myosin and good agreement with the data gathered by electron microscopy and X-ray diffraction methods. The results suggest that the force is generated not only by the myosin cross-bridges but also by the thin filaments; the former acts by cyclical unwrapping and wrapping the thick filament backbone, and the latter byelongation. © 2011 by the authors; licensee MDPI, Basel, Switzerland. Source

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