Dysferlin expression after normal myoblast transplantation in SCID and in SJL mice.

Limb girdle muscular dystrophy type 2B form and Miyoshi myopathy are both caused by mutations in the recently cloned gene dysferlin. In the present study, we have investigated whether cell transplantation could permit dysferlin expression in vivo. Two transplantation models were used: SCID mice transplanted with normal human myoblasts, and SJL mice, the mouse model for limb girdle muscular dystrophy type 2B and Miyoshi myopathy, transplanted with allogeneic primary mouse muscle cell cultures expressing the beta-galactosidase gene under control of a muscle promoter of Troponin I. FK506 immunosuppression was used in the non-compatible allogeneic model. One month after transplantation, human and mouse dysferlin proteins were detected in all transplanted SCID and SJL muscles, respectively. Co-localization of dysferlin and human dystrophin or beta-galactosidase-positive fibers was observed following the transplantation of myoblasts. Dysferlin proteins were monitored by immunocytochemistry and Western blot. The number of dysferlin-positive fibers was 40-50% and 20-30% in SCID and SJL muscle sections, respectively. Detection of dysferlin in both SCID mice and dysferlin-deficient SJL mouse shows that myoblast transplantation permits the expression of the donor dysferlin protein.

Prevalence of primary resistance to zidovudine and lamivudine in drug-naive human immunodeficiency virus type-1 infected patients: high proportion of reverse transcriptase codon 215 mutant in circulating lymphocytes and free virus.

The presence of primary zidovudine (AZT)-resistance (mutation T215Y/F) or lamivudine (3TC)-resistance (mutation M184V) was evaluated in 90 drug-naive patients infected with human immunodeficiency virus type-1 (HIV-1) between 1987 and 1997. The proportion of mutant strains in proviral samples or plasma viral samples was determined using a differential hybridization assay. Mutation T215Y/F was found in five (5.6%) patients infected between 1994 and 1997, whereas none of these patients harbored the mutation M184V. The T215Y/F mutation was present in the virus and/or provirus and persisted for at least two years. In one patient, the mutant provirus was associated with only wild-type free virus. Four of these patients were followed, and two were treated subsequently to a regimen containing AZT but with low response. The persistence of primary resistance mutations might depend on the proportion of these mutations at the time of infection, although mutant provirus might not give rise to replicating variants.

Correlation between antiretroviral resistance mutations, biological parameters, and clinical evolution in zidovudine-treated patients infected with human immunodeficiency virus type 1.

To evaluate the correlation between zidovudine (ZDV) resistance mutations of human immunodeficiency virus type 1 (HIV-1), biological parameters, and clinical evolution, 111 HIV-1-infected patients treated with ZDV were studied. Specific mutations at codons 70, 215, and 41 in the HIV-1 reverse transcriptase coding region conferring resistance to ZDV were detected using a selective polymerase chain reaction. The appearance of ZDV resistance mutations was significantly correlated with baseline clinical stage, CD4+ cell count, and viral load, but not with duration of ZDV therapy or p24 antigen level. In univariate analysis, results showed a prognostic role of mutations at codons 215 and 41 for clinical progression to the acquired immune deficiency syndrome (AIDS) or death. In multivariate analysis after controlling for viral load, CD4+ cell count, and clinical stage, the presence of the mutation at codon 215 (but not at codon 41) remained an independent predictor of subsequent clinical evolution.