Analysis of apoptosis regulatory genes expression in the bone marrow (BM) of adult de novo Myelodysplastic Syndromes (MDS)

The aim of the present study was to examine caspases, granzyme B and bcl-2 family mRNA expression and the degree of apoptosis in the bone marrow (BM) of 46 Myelodysplastic Syndromes (MDS) and to correlate our findings with clinical parameters. The degree of apoptosis was determined by Annexin V, whereas expression of genes was determined using a multiprobe RNase Protection System. A positive correlation was found between caspases 8, 5, 3, 2, 1 and the level of apoptosis. bfl1 and mcl1 levels were significantly higher in patients with BM blasts >5%. Cases with ratio of bid expression >1 compared to normal pool were associated with IPSS values < or =1.

Contribution of constitutive activation of Akt to the pathogenesis of mantle cell lymphoma (MCL) independent of PTEN protein expression

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Background: To determine whether the PI3K/Akt signaling pathway is involved in the pathogenesis of mantle cell lymphoma (MCL), we investigated the phosphorylation status of Akt in primary MCL cases and cell lines. We also sought to determine whether loss of the phosphatase PTEN is the mechanism of Akt activation in MCL. Methods: We evaluated the protein levels of Akt, phosphorylated Akt and PTEN in 15 primary MCL cases and 2 cell lines by immunoblotting Results: Akt was phosphorylated in 3 of 15 MCL cases and in 2 of 2 mantle cell lymphoma cell lines. PTEN protein was expressed in 15 of 15 primary mantle cell lymphoma cases and in 2 of 2 MCL cell lines. Conclusions: We conclude that constitutive activation of the PI3K/Akt pathway contributes to the pathogenesis of MCL. Loss of PTEN protein expression is not the responsible mechanism for Akt activation. Alternative mechanisms of Akt activation are being evaluated to identify markers predictive for response to PI3K/Akt inhibitors in MCL.

No significant financial relationships to disclose.

Enhanced in-vitro activity of liposome-trapped penicillin-G against Pseudomonas aeruginosa

The growth inhibition of four Pseudomonas aeruginosa strains by liposome-trapped penicillin-G was investigated. There were indications of an association of the efficacy of liposomal penicillin-G with the nature of the 0-antigenic polymeric side chain. Namely, P28-800 and PCF-95 strains, characterized by a rough polysaccharide chain, were the most susceptible, whereas strain P28-0, possessing an intact lipopolysaccharide, resisted the activity of the entrapped drug. Among the rough strains, P642, a beta-lactamase producer, was not affected by the encapsulated drug. The composition of liposomes seems to have a significant impact in arresting the growth of the P. aeruginosa strain.