Cellular issues relating to the resistance of HIV to antiretroviral agents.

It has been proposed that the declining efficiency of antiretroviral agents in human immunodeficiency virus (HIV) infection may also depend on cellular factors at their site of action. Two in particular have been proposed: (i) the defective intracellular metabolism of NRTI in target cells and the altered uptake; and (ii) efflux of nucleoside reverse transcriptase inhibitors (NRTI) and protease inhibitors (PI) by cellular transporter molecules. Several studies have shown that: changes in the activities of various purine and pyrimidine biosynthetic enzymes may occur in lymphocytes of HIV-infected patients; HIV-infected patients on prolonged treatment with nucleoside analogues, e.

Combination of Cytosine-Arabinoside (ARA-C), Cyclophosphamide and Prednisone in the Treatment of B-Chronic Lymphocytic Leukemia in Advanced Stages and Progressive Disease.

Recently the major advances in B-chronic lymphocytic leukemia (B-CLL) have been in defining biological characteristics and prognostic criteria. However it remains to be established which is the best therapeutic approach following the first line treatment, particularly when the patients are completely unresponsive to the standard treatment using Chlorambucil (CHL) and Prednisone (PDN) and the disease is progressive. We report the results of a combination regimen using Cytosine-Arabinoside (ARA-C), Cyclophosphamide (CTX) and PDN in 19 B-CLL patients with advanced disease, resistant to CHL + PDN.