Chromosome banding analysis and genomic microarrays are both useful but not equivalent methods for genomic complexity risk stratification in chronic lymphocytic leukemia patients

Genome complexity has been associated with poor outcome in patients with chronic lymphocytic leukemia (CLL). Previous cooperative studies established five abnormalities as the cut-off that best predicts an adverse evolution by chromosome banding analysis (CBA) and genomic microarrays (GM). However, data comparing risk stratification by both methods are scarce. Herein, we assessed a cohort of 340 untreated CLL patients highly enriched in cases with complex karyotype (CK) (46.5%) with parallel CBA and GM studies. Abnormalities found by both techniques were compared. Prognostic stratification in three risk groups based on genomic complexity (0-2, 3-4 and ≥5 abnormalities) was also analyzed. No significant differences in the percentage of patients in each group were detected, but only a moderate agreement was observed between methods when focusing on individual cases (κ=0.507; P<0.001). Discordant classification was obtained in 100 patients (29.4%), including 3% classified in opposite risk groups. Most discrepancies were technique-dependent and no greater correlation in the number of abnormalities was achieved when different filtering strategies were applied for GM. Nonetheless, both methods showed a similar concordance index for prediction of time to first treatment (TTFT) (CBA: 0.67 vs. GM: 0.65) and overall survival (CBA: 0.55 vs. GM: 0.57). High complexity maintained its significance in the multivariate analysis for TTFT including TP53 and IGHV status when defined by CBA (hazard ratio [HR] 3.23; P<0.001) and GM (HR 2.74; P<0.001). Our findings suggest that both methods are useful but not equivalent for risk stratification of CLL patients. Validation studies are needed to establish the prognostic value of genome complexity based on GM data in future prospective studies.     

SIRT1 activation mediates heat-induced survival of UVB damaged Keratinocytes

Background

Exposure to heat stress after UVB irradiation induces a reduction of apoptosis, resulting in survival of DNA damaged human keratinocytes. This heat-mediated evasion of apoptosis appears to be mediated by activation of SIRT1 and inactivation of p53 signalling. In this study, we assessed the role of SIRT1 in the inactivation of p53 signalling and impairment of DNA damage response in UVB plus heat exposed keratinocytes.

Results

Activation of SIRT1 after multiple UVB plus heat exposures resulted in increased p53 deacetylation at K382, which is known to affect its binding to specific target genes. Accordingly, we noted decreased apoptosis and down regulation of the p53 targeted pro-apoptotic gene BAX and the DNA repair genes ERCC1 and XPC after UVB plus heat treatments. In addition, UVB plus heat induced increased expression of the cell survival gene Survivin and the proliferation marker Ki67. Notably, keratinocytes exposed to UVB plus heat in the presence of the SIRT1 inhibitor, Ex-527, showed a similar phenotype to those exposed to UV alone; i.e. an increase in p53 acetylation, increased apoptosis and low levels of Survivin.

Conclusion

This study demonstrate that heat-induced SIRT1 activation mediates survival of DNA damaged keratinocytes through deacetylation of p53 after exposure to UVB plus heat

     

Colonization of the oral cavity by Candida species: risk factors in long-term geriatric care

The population of elderly people in hospitals for long-term geriatric care presents many risk factors for nosocomial infection by Candida species. The aim of this work was to reduce the risk of C. albicans nosocomial infections starting from colonization of the oral cavity. The population of concern was the patients in long-stay geriatrics units; a sample of 110 people was selected by drawing lots. The clinical and biological parameters of each patient included in the study were recorded. The oral cavity was colonized by Candida spp in 67% of cases. The distribution of the strains showed that C. albicans was the most frequently identified strain, followed by C. glabrata; of the 73 patients with at least one strain of Candida spp., 47 had a clinically diagnosed candidiasis (64.4%). The wearing of dentures was not statistically linked with the development of oral candidiasis. Detecting which patients have been colonized, identifying the risk factors and applying preventive measures should reduce the probability of elderly people falling into the vicious circle of infection-malnutrition-immune-depression.     

CD63 tetraspanin slows down cell migration and translocates to the endosomal-lysosomal-MIICs route after extracellular stimuli in human immature dendritic cells

We analyzed herein whether members of the tetraspanin superfamily are involved in human immature dendritic cell (DC) functions such as foreign antigen internalization, phagocytosis, and cell migration. We show that CD63, CD9, CD81, CD82, and CD151 are present in immature DCs. Whereas CD9 and CD81 are mostly expressed at the cell surface, CD63 and CD82 are also located in intracellular organelles. Complexes of monoclonal antibody (Mab) FC-5.01-CD63 or Fab-5.01-CD63 were rapidly translocated "outside-in" and followed the endocytic pathway through early endosomes and lysosomes, reaching major histocompatibility complex (MHC) class II-enriched compartments (MIICs) in less than one hour. Internalization of CD63 was also observed during Saccharomyces cerevisiae phagocytosis. Moreover, an association of CD63 with the beta-glycan receptor dectin-1 was observed. Mabs against CD9, CD63, CD81, and CD82 enhanced by 50% the migration induced by the chemokines macrophage inflammatory protein-5 (MIP-5) and MIP-1alpha. Concomitantly, Mabs against CD63 and CD82 diminished the surface expression of CD29, CD11b, CD18, and alpha5 integrins. By immunoprecipitation experiments we found that CD63 associated with integrins CD11b and CD18. These results suggest that CD9, CD63, CD81, and CD82 could play a role in modulating the interactions between immature DCs and their environment, slowing their migratory ability. However, only CD63 would intervene in the internalization of complex antigens.     

Toll-like receptor 4 is not involved in host defense against pulmonary Legionella pneumophila infection in a mouse model

Legionella pneumophila is a gram-negative microorganism that causes a severe pneumonia known as "legionnaires disease." Toll-like receptor 4 (TLR4) transduces the lipopolysaccharide signal and is therefore considered to play a role in host defense against gram-negative bacterial infection. To determine the role of TLR4 in L. pneumophila pneumonia, C3H/HeJ mice, which display a nonfunctional gene encoding TLR4 (TLR4), and wild-type (wt) C3H/HeN mice were intranasally inoculated with L. pneumophila serogroup 1. Infection proceeded in an identical way in TLR4 mutant and wt mice, as reflected by similar bacterial outgrowth in the lungs. In addition, the inflammatory responses to L. pneumophila infection-as assessed by histopathologic analysis, cell influx in bronchoalveolar lavage fluid, myeloperoxidase activity in lungs, and lung cytokine concentrations-were indistinguishable in TLR4 mutant and wt mice. These data suggest that, in this mouse model, TLR4 does not play a role in resistance to L. pneumophila.     

Effect of supplementation with antioxidants upon long-term risk of hypertension in the SU.VI.MAX study: association with plasma antioxidant levels

OBJECTIVE: To assess the effects of supplementation with a combination of antioxidant vitamins and trace elements, at nutritional doses, upon the 6.5-year risk of hypertension in the SU.VI.MAX trial. To describe the association between baseline plasma antioxidant levels and the same long-term risk using observational data from the study. SETTING: A total of 5086 adults from the SU.VI.MAX trial, a randomized primary prevention trial. RESULTS: Compared with the placebo group, no effect of supplementation upon the 6.5-year risk of hypertension could be detected (odds ratio, 1.04 and 95% confidence interval, 0.87-1.23 in men; and odds ratio, 1.10 and 95% confidence interval, 0.95-1.29 in women). Furthermore, compared with men in the first tertile, those in the second and third tertiles of serum baseline levels of beta-carotene presented a lower risk of hypertension in both the placebo and supplementation groups. Multivariate-adjusted odds ratios (95% confidence interval) were 0.70 (0.44-1.12) and 0.53 (0.33-0.86) in the placebo group, and were 0.59 (0.37-0.94) and 0.67 (0.42-1.07) in the supplementation group. In women, a decreasing trend was observed with vitamin C levels and risk of hypertension in the intervention group. No association could be shown between vitamin E and trace element plasma levels and the risk of hypertension. CONCLUSIONS: Despite an inverse association between baseline plasma levels of beta-carotene in men and the risk of developing hypertension, we could not demonstrate any beneficial effect of low-dose antioxidant supplementation upon the 6.5-year risk of hypertension in the randomized analysis.