Cytomegalovirus UL97 and Glycoprotein B (gB) Sequences in Tissues from Immunocompromised Patients with Ganciclovir-resistant Virus Infection

Abstract

The pathogenesis of ganciclovir-resistant cytomegalovirus (CMV) was investigated by analysing UL97 and gB sequences in tissues obtained from 4 immunocompromised patients with infections caused by ganalciclovir-resistant virus. UL97 and gB sequences were obtained by automated sequencing of CMV DNA amplified from lysates prepared from deparaffinized tissue sections. Patient 1 contained wild-type UL97 and gB3 sequences. Patient 2 harboured genetically distinct viruses in his lung: one with a ganciclovir-resistance UL97 mutation and a gB3 genotype, and another without UL97 mutations and a gB1 genotype. In patient 3, a ganciclovir-resistant UL97 mutant virus with a gB1 genotype was cultured from the lung, whereas the CMV in the brain did not contain mutations and its genotype was gB2. In patient 4, ganciclovir-resistance UL97 sequences were found in oesophageal tissue prior to the isolation of a ganciclovir-resistant CMV from the blood. All viruses in this patient had a gB3 genotype. CMV containing ganciclovir-resistance UL97 mutations may cause end-organ disease in immunocompromised individuals. In these subjects, CMV circulating in the blood may have similar or different UL97 and gB genotypes than the virus causing end-organ disease.

High Throughput Screening of Valganciclovir in Acidic Microenvironments of Polyester Thin Films

“…The half-life in PBS with pH 7.4 at T = 23.5 °C was calculated at t 1/2 = 36.7 h ± 0.3. At T = 37 °C, a t 1/2 = 10.7 ± 0.3 h was measured, which agrees with the 11 h half-life determined by Li et al in similar conditions [20]. At pH 1 and T = 23.5 °C, valganciclovir showed virtually no degradation over a time period of 22 h, signifying that the drug is stable for several hours before quantitation needs to be done—an important aspect for automated high-throughput screening protocols.…”

“…The half-life for valganciclovir in the 20% drug polyester film was calculated to be 95.0 days (81.5 days to 113.6 days) and 118.5 days (109.5 days to 129.1 days) for the 10% valganciclovir film. Comparing these two half-lives to the half-lives of valganciclovir reported by Li et al [20] 1999 at different pH, suggests an environmental pH of approximately 4.4 ± 0.3. Although there are numerous reports on the pH microclimate of PLGA with varying pH values, they all agree on an increasingly acidic pH ranging from 1.5 to 4.7 [21,22,23].…”

“…With a direct link between the half-life of valganciclovir to pH, we suggest that the intrinsic low pH of the polymer mixture provides an acidic microenvironment that inhibits valganciclovir from degrading during our drug release trials [20]. It is this increase in half-life inside of the polymer that makes it feasible to consider PLGA thin films as well-suited drug reservoirs for valganciclovir.…”