Synthesis and antiviral evaluation of polyhalogenated imidazole nucleosides: Dimensional analogues of 2,5,6-trichloro-1-(beta-D-ribofuranosyl)benzimidazole
JOURNAL OF MEDICINAL CHEMISTRY
Authors: Chien, TC; Saluja, SS; Drach, JC; Townsend, LB
Abstract
A series of polyhalogenated imidazole nucleosides were designed and synthesized as ring-contracted analogues of 2,5,6-trichloro-1-(beta-D-ribofuranosyl)benzimidazole (TCRB) and its 2-bromo analogue (BDCRB) in an effort to explore the spatial limitation of the active pocket(s) in the target protein(s). 2,4,5-Trichloro-, 2-bromo-4,5-dichloro-, and 2,4,5-tribromoimidazole nucleosides were prepared by a condensation of the preformed heterocycles with the appropriate sugar precursors. The ribofuranosyl and xylofuranosyl analogues were prepared by a direct glycosylation using the Vorbruggen's silylation method and provided exclusively the beta-anomers. The arabinofuranosyl analogues were prepared by the sodium salt method to give both the alpha-and beta-anomers. The absolute configurations were established by H-1 NMR spectroscopy. Alkylation of the polyhalogenated imidazoles with the appropriate bromomethyl ethers gave the acyclic acyclovir and ganciclovir analogues. In general, the parent polyhalogenated imidazoles showed some activity against human cytomegalovirus (HCMV) (IC50 similar to 35 muM). However, with the exception of two tribromo analogues (7c, 13c-beta), most of their nucleoside derivatives were inactive against both HCMW and herpes simplex virus type-1 (HSV-1) and were not cytotoxic. The results suggest that the ring-contracted nucleoside analogues of TCRB and BDCRB interacted weakly or not at all with viral and cellular targets.
Analysis of T-cell receptor gene rearrangement in lymph nodes of patients with mycosis fungoides - Prognostic implications
ARCHIVES OF DERMATOLOGY
Authors: Kern, DE; Kidd, PG; Moe, R; Hanke, D; Olerud, JE
Abstract
Objective: To determine the prognostic value of analyzing lymph node (LN) DNA from patients with mycosis fungoides for the presence of a monoclonal T-cell population. Design: Inception cohort study. Setting: A tertiary care referral center in Seattle, Wash. Patients: Fifty-five uniformly staged patients with the diagnosis of mycosis fungoides and who had a lymph node biopsy, 21 with clinically abnormal nodes and 34 with normal nodes. Main Outcome Measures: Lymph nodes were evaluated by Southern blot analysis for T-cell receptor beta-chain (TCRB) gene rearrangement and by histopathologic examination for the LN classification using the National Cancer Institute system. Patients were observed clinically for a mean (+/- SD) of 4.7 +/- 3.4 years. Results: Patients with detectable TCRB gene rearrangement in lymph node DNA had an increased likelihood of a poor clinical outcome and a decreased probability of survival (P<.001 for both) compared with patients with the TCRB germline. Although patients with clinically enlarged nodes were more likely to have the TCRB gene rearranged, those with normal nodes and the TCRB gene rearranged also had a poor clinical outcome and a decreased probability of survival. Similar to those with the TCRB gene rearranged, most patients with advanced histopathologic changes (LN3 and LN4) had a poor prognosis. The presence of a rearranged TCRB gene, however, correctly predicted some patients with intermediate LN scores (LN2) who had a poor clinical outcome. Conclusions: Detection of a monoclonal T-cell population, as demonstrated by a rearranged TCRB gene on Southern blot analysis, in LNs of patients with mycosis fungoides is predictive of a poor clinical outcome and a reduced probability of survival. Lymph node TCRB gene analysis provides additional prognostic information for patients with mycosis fungoides with intermediate LN histopathology.