Imipramine Is an Orally Active Drug against Both Antimony Sensitive and Resistant Leishmania donovani Clinical Isolates in Experimental Infection

Background: In an endeavor to find an orally active and affordable antileishmanial drug, we tested the efficacy of a cationic amphiphilic drug, imipramine, commonly used for the treatment of depression in humans. The only available orally active antileishmanial drug is miltefosine with long half life and teratogenic potential limits patient compliance. Thus there is a genuine need for an orally active antileishmanial drug. Previously it was shown that imipramine, a tricyclic antidepressant alters the protonmotive force in promastigotes, but its in vivo efficacy was not reported. Methodology/Principal Findings: Here we show that the drug is highly active against antimony sensitive and resistant Leishmania donovani in both promastigotes and intracellular amastigotes and in LD infected hamster model. The drug wasfound to decrease the mitochondrial transmembrane potential of Leishmania donovani (LD) promastigotes and purified amastigotes after 8 h of treatment, whereas miltefosine effected only a marginal change even after 24 h. The drug restores defective antigen presenting ability of the parasitized macrophages. The status of the host protective factors TNF a, IFN c and iNOS activity increased with the concomitant decrease in IL 10 and TGF b level in imipramine treated infected hamsters and evolution of matured sterile hepatic granuloma. The 10-day therapeutic window as a monotherapy, showing about 90% clearance of organ parasites in infected hamsters regardless of their SSG sensitivity. Conclusions: This study showed that imipramine possibly qualifies for a new use of an old drug and can be used as an effective orally active drug for the treatment of Kala-azar

Synthesis, in vitro anti-HIV and anti-hepatitis B activities and pharmacokinetic properties of amphiphilic heterodinucleoside phosphates containing ddC and AZT

Amphiphilic heterodinucleoside phosphates containing AZT and ddC as antiviral monomer were synthesized according to the hydrogenphosphonate method and evaluated in vitro against HIV. dT-N4-pamddC was the most active (IC50 = 40 microM, EC50 = 80 nM) and least toxic (TI = 524) dimer and it exhibited also strong antiviral effects against eight AZT-resistant HIV strains. The ddC-containing heterodimers additionally inhibited HBV replication by 50-80% at 50 microM in Hep G2 2.2.15 cells

Cloning of murine interferon gamma receptor cDNA: expression in human cells mediates high-affinity binding but is not sufficient to confer sensitivity to murine interferon gamma

A full-length cDNA encoding the murine interferon gamma (IFN-gamma) receptor was isolated from a lambda gt11 library using a human IFN-gamma receptor cDNA probe. The deduced amino acid sequence of the murine IFN-gamma receptor shows approximately 53% homology to its human counterpart but no homology to other known proteins. Murine IFN-gamma receptor cDNA was expressed in human HEp-2 cells, which do not bind murine IFN-gamma and are insensitive to its action. Transfectants displayed the same binding properties as mouse cells. The biological responsiveness of such transfectants to various biological effects of both human and murine IFN-gamma was investigated, including modulation of major histocompatibility complex class I and class II antigen expression, inhibition of cell growth, and antiviral activity. Like parental HEp-2 cells, these transfectants responded only to human, but not to murine, IFN-gamma. Inversely, mouse L929 cells transfected with human IFN-gamma receptor cDNA were insensitive to human IFN-gamma. These results confirm and extend previous findings, suggesting that species-specific cofactors are needed for IFN-gamma-mediated signal transduction