Jean-Marc Dubois

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Ion channels and cell volume control participate in a wide variety of cellular functions, including cell proliferation. According to the “pump-leak model” or the “double Donnan system”, the cell volume is constant in physiological medium so long as the cell metabolism and the Na-K pump are not inhibited and the passive Na+ permeability is not dramatically(More)
Potassium channels, the most diverse superfamily of ion channels, have recently emerged as regulators of carcinogenesis, thus introducing possible new therapeutic strategies in the fight against cancer. In particular, the large conductance Ca(2+)-activated K(+) channels, often referred to as BK channels, are at the crossroads of several tumor-associated(More)
The homeostasis of the central nervous system is highly controlled by glial cells and is dramatically altered in the case of glioma. In this respect, the complex connection between cell size and division is of particular importance and needs clarifying. In order to investigate this connection, cell number and volume were measured in C6 rat glioma cells(More)
In the 1870's, Ludwig Boltzmann proposed a simple equation that was based on the notion of atoms and molecules and that defined the probability of finding a molecule in a given state. Several years later, the Boltzmann equation was developed and used to calculate the equilibrium potential of an ion species that is permeant through membrane channels and to(More)
The aim of this work was to examine the effects of changes in external K+ concentration (K o ) around its physiological value, of various K+ channels blockers, including internal Cs+, of vacuolar H+-ATPase inhibitors and of the protonophore CCCP on the resting potential and the voltage-dependent K+ current of differentiated neuroblastoma x glioma hybrid(More)
Intracellular calcium ([Ca2+]i), cell volume, membrane potential and currents were measured in neuroblastoma×glioma hybrid cells to gain insight into how [Ca2+]i controls cell volume. [Ca2+]i was increased by fluid shear stress, mechanical stimulation of the cells, the Ca2+ ionophore A23187, caffeine and thapsigargin. The increase in [Ca2+]i induced by(More)
Cell volume controls many functions and is itself regulated. To study cell volume regulations, the mean volume of C6-BU-1 rat glioma cells was electronically measured under isotonic and anisotonic conditions. Two isotonic solutions were used containing either normal (solution 1) or low (solution 2) NaCl. Anisotonicity was induced by changing NaCl or sucrose(More)
The fully activated I–V relation (ĪK) for the potassium current (IK) in the Ranvier node was obtained in two ways: (a) by measuring IK values on stepping to various potentials, at the end of a depolarizing clamp pulse which fully activated IK; (b) by dividing the time dependent change in IK seen on depolarizing to a certain potential, by the time dependent(More)
For decades, the connection between cell size and division has been the subject of controversy. While in yeast, cell size checkpoints coordinate cellular growth with cell-cycle progression, it has been recently shown that large and small Schwann cells proliferate at the same rate (Conlon and Raff, 2003, J Biol 2:7). From this point of view, it is important(More)
Vacuolar H(+) ATPase (V-ATPase) activity is essential for many cellular processes, including intracellular membrane traffic, protein processing and degradation, and receptor-mediated endocytosis. Proton transport by V-ATPases could also play a role during cell transformation, tumorigenesis, and cell metastasis, and V-ATPase c-subunit overexpression was(More)