Publications

The high replication rate of HIV, together with the low fidelity of its reverse transcriptase, provides the virus with an unprecedented genomic flexibility. This allows a fast adaptation to selective pressure, including antiviral drugs, resulting in the development of drug-resistant strains. The present improvements in the treatment of AIDS patients are at least partly owing to antiviral therapy. To assess the implications of HIV drug resistance on patient management, drug resistance assays for clinical HIV isolates are widely being used. Ideally, monitoring drug resistance should help clinicians in their treatment decisions. If patients would really benefit clinically from this strategy, then the gain from clinical improvement and from omitting drugs to which the virus is already resistant would outweigh the cost of drug resistance testing. In the next few years, researchers should consolidate the clinical benefit of antiviral drug resistance testing, and for this they need fast, reliable and cheap assays. All present assays are in vitro assays, which can only partly mimic the in vivo situation with confounding factors, such as cellular resistance (1). Efforts are presently made to establish in vivo assays (2; see also Chapter 10 ).

Ten saponins isolated from the leaves of Maesa lanceolata were tested for their antiviral, haemolytic and molluscicidal activities. The influence of the substitution pattern of these acylated triterpenoid saponins on their biological activities was investigated and structure-activity relationships were established. Maesasaponin VI(2) (3 beta-O-[[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-galactopyranosyl-(1 --> 3)]-[beta-D-galactopyranosyl-(1 --> 2)]-beta-D-glucopyranuronyl]-21 beta,22 alpha-diangeloyloxy-13 beta,28-epoxyolean-16 alpha,28 alpha-diol), the most potent molluscicidal compound (LC(50) 0.5 ppm), also showed virucidal and haemolytic activity. In general, 21,22-diacylation appeared to be associated with a virucidal (reduction factor of the viral titer > or = 10(3) at 50 microg/ml) and haemolytic activity (HC(50) < or = 1 microg/ml).

The anti-human immunodeficiency virus (HIV) activity of aryloxyphosphoramidate protides of a number of anti-HIV nucleoside analogues was assessed in resting primary monocyte-macrophages (M/M). While 2',3'-dideoxythymidine (d4T), 2',3'-dideoxyadenosine (ddA), and 2',3'-dideoxy-2',3'-didehydroadenosine (d4A) protides showed an anti-HIV activity that was 25- to 625-fold greater than the parent nucleotides d4T, ddA, and d4A, respectively, other aryloxyphosphoramidate protides showed similar or even lower anti-HIV activities than their parent compounds. This variable anti-HIV effect is most likely related to the different dynamics of intracellular nucleoside monophosphate release from the protides. Our results indicate the potential advantage of therapeutic use of this approach for some nucleotide analogues to affect HIV replication in M/M, one of the major reservoirs of HIV in vivo.

Abstract The 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) derivatives have been found to be potent and specific inhibitors of human immunodeficiency virus type 1 (HIV-1) replication in vitro. Among the compounds, MKC-442 (6-benzyl-1-ethoxymethyl-5-isopropyluracil) has recently been chosen as a candidate for clinical efficacy and safety studies in patients with the acquired immune deficiency syndrome (AIDS).

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

No abstract is provided for this article.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The remarkably potent and specific activity against varicella-zoster virus (VZV) shown by 2'-deoxynucleosides of furo[2,3-d]pyrimidin-2(3H)-one and related ring systems is dependent on key structural features including the length and nature of the side-chain at C6 and the structure and stereochemistry of the sugar moiety at N3. Removal of the 3'-hydroxyl group from potent anti-VZV 2'-deoxynucleosides results in loss of the VZV activity, but such 2',3'-dideoxynucleoside analogues have shown anti-HCMV activity. We now report acyclic analogues with comparable side-chains at C6, but with the sugar moiety at N3 replaced with the (2-hydroxyethoxy)methyl group (present in the antiherpes drug acyclovir). Examples of both furo[2,3-d]- and pyrrolo[2,3-d]pyrimidin-2(3H)-one acyclic analogues were prepared and evaluated in a number of virus-infected cells and in tumor cell cultures. Certain of the long-chain analogues showed activity against VZV and HCMV. No significant activity against other DNA and RNA virus replication or against tumor cell proliferation was observed.