4 research outputs found
A Possible Role for Singlet Oxygen in the Degradation of Various Antioxidants. A Meta-Analysis and Review of Literature Data
The thermodynamic parameters Eact, ΔH≠, ΔS≠, and ΔG≠ for various processes involving antioxidants were calculated using literature kinetic data (k, T). The ΔG≠ values of the antioxidants’ processes vary in the range 91.27–116.46 kJmol−1 at 310 K. The similarity of the ΔG≠ values (for all of the antioxidants studied) is supported to be an indication that a common mechanism in the above antioxidant processes may be taking place. A value of about 10–30 kJmol−1 is the activation energy for the diffusion of reactants depending on the reaction and the medium. The energy 92 kJmol−1 is needed for the excitation of O2 from the ground to the first excited state (1Δg, singlet oxygen). We suggest the same role of the oxidative stress and specifically of singlet oxygen to the processes of antioxidants as in the processes of proteinaceous diseases. We therefore suggest a competition between the various antioxidants and the proteins of proteinaceous diseases in capturing singlet oxygen’s empty π* orbital. The concentration of the antioxidants could be a crucial factor for the competition. Also, the structures of the antioxidant molecules play a significant role since the various structures have a different number of regions of high electron density
Fish evaluation of additional cytogenetic aberrations and hyperdiploidy in childhood Burkitt lymphoma
Beyond MYC rearrangement, Burkitt lymphoma (BL) often presents with
additional aberrations. Biopsy touch imprints from 72 children with BL
were tested with interphase fluorescence in-situ hybridization (i-FISH)
for MYC, BCL2, BCL6, IGH, IGK and IGL rearrangements and copy-number
aberrations involving 1q21/1p32, 7cen/7q31, 9cen/9p21, 13q14/13q34 and
17cen/17p13. Diploid status deviations were investigated with chromosome
enumeration probes. MYC rearrangement was demonstrated in all cases.
Additional aberrations included +1q (21/72:29.2%), +7q (14/72:19.4%),
13q- (14/72:19.4%), 9p-(6/72:8.3%) and hyperdiploidy (6/72:8.3%).
Advanced clinical stage IV, +7q and 9p- were associated with shorter
overall survival, with stage IV and +7q retaining prognostic
significance on multivariate analysis. No relapse or death was reported
among the hyperdiploid cases. This i-FISH investigation provides
information on the genetic profile of BL and may prove valuable for
patients with no karyotype analysis. Demonstration of hyperdiploidy
could evolve research on clonal evolution pathways and probably identify
a subgroup of children with favorable prognosis