Modulation of Radiation-induced Chromosome Aberrations by DMSO, an OH Radical Scavenger. 1: Dose—response Studies in Human Lymphocytes Exposed to 220 kV X-rays

Abstract

Human G0 lymphocytes were exposed to 220 kV X-radiation in the presence or absence of DMSO, an efficient selective scavenger of OH radicals. Our studies demonstrate that DMSO affects a concentration-dependent modulation of induced asymmetrical aberrations in human lymphocytes exposed to approximately 3.0 Gy, with maximum protectible fractions of approximately 70 percent at DMSO concentrations of greater than or equal to 1 M. The dose dependency for dicentrics in lymphocytes acutely exposed to X-ray doses of 0.51 to 4.98 Gy in the absence of DMSO is adequately described by the linear-quadratic dose-response function Y = alpha D + beta D2. Data from duplicate cultures exposed in the presence of 1 M DMSO produce an excellent fit to the regression function modified as follows: Y(+ DMSO) = alpha(delta D) + beta(delta D)2 where the 'dose modifying' factor delta = 0.501. We interpret these findings as providing evidence that OH radical-mediated lesions in DNA account for approximately 50 percent of the dose dependency for dicentrics resulting from either one-track or two-track events, following exposures of non-cycling cells to moderate-to-high doses of low LET radiation. These data may be used in additional calculations to derive an estimate of approximately 6 x 10(8) s-1 for the rate of reaction of OH radicals with DNA targets involved in aberration formation.

Antioxidant and Radioprotective Effects of Ocimum Flavonoids Orientin and Vicenin in Escherichia coli

“…A similar dose dependence has been reported for chromosome protection by DMSO 15 . The mutagenesis inhibitory activity of flavonoids has been reported to be concentration-dependent; at lowest doses, these exhibited competitive inhibition and at higher doses, exhibited a mixed inhibition pattern 16 Thus, using the Escherichia coli mutants deficient in superoxide dismutase and catalase genes, it was demonstrated that the Ocimum flavonoids, orientin and vicenin, are excellent reactive oxygen species scavengers.…”

Impairment of excitatory amino acid transporter activity by oxidative stress conditions in retinal cells: effect of antioxidants

“…Therefore, we tested the effect of 100 jiM Vit E on the uptake of (P>0.05) the formation of lipid peroxidation products in cells exposed to ascorbate/Fe2 ( Table 2). The antioxidant effect of DMSO, which is probably due to its SO groups (29), may account for part of the small protecting effect of Vit E on the uptake of D-[3Hiaspartate by cells subjected to the oxidant pair (Fig. 2).…”

Combined effect of viscous dissipation and thermal radiation on fluid flows over a non-linearly stretched permeable wall

“…Authors assume that the maximum protectable fraction is related to the indirect action of the ionizing radiation. Other chemical compounds like DMSO at 1 M have a maximum protectable fraction of about a 70% [14]. The active form of amifostine (WR-1065) showed a maximum protective fraction of 87% at 8 mM [15].…”

“…Chromosome aberrations have been used as a sensitive monitor of DNA damage in studies of several radioprotectors [6,14,15]. Recently, we have reported that human peripheral blood lymphocytes in vitro pretreated with 1000 μg·mL −1 of EEP and then exposed to gamma radiation, exhibited a significantly reduced incidence of chromosome aberrations [16].…”

“…The observed frequencies of dicentrics were fitted by negative exponential function (see (1)) using the maximum likelihood analysis of regression models [14]:…”