Stochastic Modeling and Simulation of Ion Transport through Channels

Ion channels are of major interest and form an area of intensive research in the fields of biophysics and medicine since they control many vital physiological functions. The aim of this work is on one hand to propose a fully stochastic and discrete model describing the main characteristics of a multiple channel system. The movement of the ions is coupled, as usual, with a Poisson equation for the electrical field; we have considered, in addition, the influence of exclusion forces. On the other hand, we have discussed about the nondimensionalization of the stochastic system by using real physical parameters, all supported by numerical simulations. The specific features of both cases of micro- and nanochannels have been taken in due consideration with particular attention to the latter case in order to show that it is necessary to consider a discrete and stochastic model for ions movement inside the channels

Well-posedness of a reaction-diffusion model with stochastic dynamical boundary conditions

We study the well-posedness of a nonlinear reaction diffusion partial differential equation system on the half-line coupled with a stochastic dynamical boundary condition, a random system arising in the description of the evolution of the chemical reaction of sulphur dioxide with the surface of calcium carbonate stones. The boundary condition is given by a Jacobi process, solution to a Brownian motion-driven stochastic differential equation with a mean reverting drift and a bounded diffusion coefficient. The main result is the global existence and the pathwise uniqueness of mild solutions. The proof relies on a splitting strategy, which allows to deal with the low regularity of the dynamical boundary condition

Laws of large numbers for interacting particle systems: from discrete to continuum: an aggregation model

Dottorato di ricerca in matematica computazionale e ricerca operativa. 11 ciclo. Coordinatore Vincenzo CapassoConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Modeling and simulating animal grouping: individual-based models

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Cellular automata and many-particle systems modeling aggregation behaviour among populations

This work was partially supported by MURST (ex 40%) 'Procesi stocastici e applicazioni' and CNRConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Disc Large 1 expression is altered by Human Papillomavirus E7/E6 proteins in organotypic cultures of human keratinocytes

Loss of cell polarity is a fundamental process in cell transformation. Among polarity proteins, we focused on human Disc Large (DLG1), which is localized mainly at adherens junctions and contributes to the control of cell proliferation. We previously demonstrated that its expression is altered in HPV-associated cervical neoplastic lesions, but the mechanisms beyond this remain unknown. In this study, we analyzed the contribution of HPV proteins to the changes in DLG1 expression in the squamous epithelium. We observed tissue and intracellular misdistribution of DLG1 when high-risk HPV-18 E7 or E6/E7 proteins were expressed in organotypic raft cultures. The viral oncoproteins induce the loss of DLG1 from the cell borders and an increase in the level of DLG1 protein, reflecting the pattern observed in cervical lesions. These findings were corroborated in cultures bearing the entire HPV-18 genome. Interestingly, changes in tissue distribution and abundance of DLG1 were also detected in organotypic cultures expressing the low-risk HPV-11 E7 or E6/E7 proteins; suggesting a conserved function among different HPV types. However, for low-risk HPVs, the subcellular localization of DLG1 at cell-to-cell contacts was predominantly maintained. This report offers new evidence of the involvement of HPV proteins in DLG1 expression pattern and our data support previous observations regarding DLG1 expression in cervical lesions.Fil: Bugnon Valdano, Marina Paula. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Argentina.Fil: Cavatorta, Ana Laura. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Argentina.Fil: Morale, Miriam Galliote. University of Sao Paulo. Institute of Chemistry. Deparment of Biochemistry; Brasil.Fil: Marziali, Federico Emanuel. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Argentina.Fil: de Souza Lino, Vanesca. University of Sao Paulo. Institute of Chemistry. Deparment of Biochemistry; Brasil.Fil: Steenbergen, Renske. VU University Medical Center. Department of Pathology; The Netherlands.Fil: Boccardo, Enrique. University of Sao Paulo. Institute of Chemistry. Deparment of Biochemistry; Brasil.Fil: Boccardo, Enrique. University of Sao Paulo. Institute of Chemistry. Deparment of Biochemistry; Brasil.Fil: Gardiol, Daniela. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Argentina

Chronic denervation of rat hemidiaphragm: maintenance of fiber heterogeneity with associated increasing uniformity of myosin isoforms

J Cell Biol. 1985 Jan;100(1):161-74. Chronic denervation of rat hemidiaphragm: maintenance of fiber heterogeneity with associated increasing uniformity of myosin isoforms. Carraro U, Morale D, Mussini I, Lucke S, Cantini M, Betto R, Catani C, Dalla Libera L, Danieli Betto D, Noventa D. Abstract During several months of denervation, rat mixed muscles lose slow myosin, though with variability among animals. Immunocytochemical studies showed that all the denervated fibers of the hemidiaphragm reacted with anti-fast myosin, while many reacted with anti-slow myosin as well. This has left open the question as to whether multiple forms of myosin co-exist within individual fibers or a unique, possibly embryonic, myosin is present, which shares epitopes with fast and slow myosins. Furthermore, one can ask if the reappearance of embryonic myosin in chronically denervated muscle is related both to its re-expression in the pre-existing fibers and to cell regeneration. To answer these questions we studied the myosin heavy chains from individual fibers of the denervated hemidiaphragm by SDS PAGE and morphologically searched for regenerative events in the long term denervated muscle. 3 mo after denervation the severely atrophic fibers of the hemidiaphragm showed either fast or a mixture of fast and slow myosin heavy chains. Structural analysis of proteins sequentially extracted from muscle cryostat sections showed that slow myosin was still present 16 mo after denervation, in spite of the loss of the selective distribution of fast and slow features. Therefore muscle fibers can express adult fast myosin not only when denervated during their differentiation but also after the slow program has been expressed for a long time. Light and electron microscopy showed that the long-term denervated muscle maintained a steady-state atrophy for the rat's life span. Some of the morphological features indicate that aneural regeneration events continuously occur and significantly contribute to the increasing uniformity of the myosin gene expression in long-term denervated diaphragm. PMID: 3965469 [PubMed - indexed for MEDLINE] PMCID: PMC2113461 Free PMC Articl