Jean-Paul Jay-Gerin

Learn More
Cellular exposure to ionizing radiation leads to oxidizing events that alter atomic structure through direct interactions of radiation with target macromolecules or via products of water radiolysis. Further, the oxidative damage may spread from the targeted to neighboring, non-targeted bystander cells through redox-modulated intercellular communication(More)
Monte Carlo simulations of the radiolysis of neutral liquid water and 0.4 M H(2)SO(4) aqueous solutions at ambient temperature are used to calculate the variations of the primary radical and molecular yields (at 10(-6)s) as a function of linear energy transfer (LET) in the range approximately 0.3 to 6.5 keV/micrometer. The early energy deposition is(More)
Monte Carlo simulations are used to investigate the effects of multiple ionization of water molecules on the yields of formation of free radical and molecular species, including molecular oxygen, in the radiolysis of pure, deaerated liquid water by using different types of radiation (1H+, 4He2+, 12C6+, and 20Ne9+ ions) up to approximately 900 keV/microm, at(More)
The "spur lifetime" (τ(s)) in the low-linear energy transfer (LET) radiolysis of supercritical water (SCW) at 400 °C has been determined as a function of water density by using a simple model of energy deposition initially in spurs, followed by the random diffusion (Brownian motion) of the species formed until spur expansion is complete. The values of τ(s)(More)
In multicellular organisms, intercellular communication is essential for homeostatic functions and has a major role in tissue responses to stress. Here, we describe the effects of expression of different connexins, which form gap junction channels with different permeabilities, on the responses of human cells to ionizing radiation. Exposure of confluent(More)
In this work, we sought to investigate the relation existing between MDR1 mRNA levels, the resistance factor (RF), and the efficiency of efflux of pirarubicin (THP) mediated by P-glycoprotein (P-gp) in multidrug-resistant (MDR) K562 sublines. The MDR K562 sublines were selected from K562/adr cells by exposure to different adriamycin concentrations: 300 nM(More)
Atherosclerosis has been implicated in myocardial infarction, stroke and a host of cardiovascular diseases. The presence of activated T lymphocytes and macrophages, and the increased expression of HLA-DR antigen are consistent with the notion of immune activity in the atherosclerotic plaque. The nature of the causative antigen has not been established(More)
This paper examines, from a chemical perspective, the hypothesis of the existence of protective enzymes whose role would be to regulate the high local nitric oxide (NO) concentrations that are released in NO-generating cells in situations of response to oxidative stress. These enzymes should play the role, with respect to NO, either of a reductase or of a(More)
In this study, polyacrylamide gel (PAG) dosimetry is used to quantitatively assess the efficiency of radiation sensitizers. The local dose enhancement caused by the K-edge absorption of certain atoms such as bromine and iodine can be employed to increase the damage to neighboring molecules and cells. Clonogenic assays can assess the radiation survival of(More)
Oxidized low density lipoproteins (LDL) are believed to play a central role in the events that initiate atherosclerosis. Antioxidants have been shown to decrease the oxidation of LDL, leading to the diminution of atherosclerosis. Since it is well-known that decreased levels of dehydroepiandrosterone (DHEA) are linked to the development of atherosclerosis,(More)