LINE-1 vectors mediate recombinant antibody gene transfer by retrotransposition in Chinese hamster ovary cells.

Retrotransposons, such as long interspersed element-1 (LINE-1), can copy themselves to other genomic loci via a transposition event (termed retrotransposition). Retrotransposons, therefore, have potential use as an efficient gene delivery tool to integrate multiple copies of a target gene into a host genome. Here, we developed a retrotransposon vector based on LINE-1 that achieves target gene integration of multiple transgene copies. The retrotransposon vector contains a neomycin resistance gene split by an intron as a marker gene, and a gene encoding an antibody single-chain variable fragment (Fv) fused with the constant antibody region (Fc) (scFv-Fc) as a model target gene. G418-resistant Chinese hamster ovary cells were generated using this retrotransposon vector, and scFv-Fc was produced in the culture medium. To regulate retrotransposition, we developed a retrotransposon vector system that separately expressed the two open reading frames (ORF1 and ORF2) of LINE-1. Genomic PCR analysis detected the transgene sequence in almost all tested clones. Compared with clones established using the intact LINE-1 vector, clones generated with the split ORF1 and ORF2 system showed similar specific scFv-Fc productivity and retrotransposition efficiency. This approach of using a retrotransposon-based vector system has the potential to provide a new gene delivery tool for mammalian cells.

Prospective comparative study of single dose versus 3-day administration of antimicrobial prophylaxis in minimum incision endoscopic radical prostatectomy.

OBJECTIVE: From the critical stand point against the overuse of antimicrobial agents, appropriate reduction of antimicrobial prophylaxis (AMP) should be considered. We have prospectively reduced AMP and evaluated the occurrence of surgical site infection (SSI) following radical retropubic prostatectomy (RRP) by minimum incision endoscopic surgery (MIES). METHODS: A total of 101 consecutive patients who underwent MIES-RRP for prostate carcinoma were classified into two groups according to AMP dose. The 3-day group of 52 patients received tazobactam sodium/piperacillin sodium (TAZ/PIPC) 2.5 g intravenously before the operation and continued twice daily until postoperative day 2, and the single dose group of 49 patients received TAZ/PIPC 2.5 g intravenously only once before the operation. Additional antimicrobial agents were given only when SSI occurred. The occurrence of SSI and remote infection (RI) were analyzed. RESULTS: There was no significant difference in the rate of SSI occurrence between the 3-day group (3.8%) and single dose group (6.1%) (P = 0.6). RI did not increase in the single dose group. CONCLUSION: Antimicrobial prophylaxis dose was successfully reduced without increasing SSI or RI. A single dose of AMP is feasible to prevent SSI and RI and would be a standard regimen in MIES-RRP. Active surveillance of postoperative infection is mandatory to promptly administer antimicrobial treatment as the need arises.