Predictive factors of postoperative septic complications after flexible ureteroscopy for urinary stones.

BACKGROUND: Flexible ureteroscopy (fURS) is one of the recommended treatments for urinary stones. Urosepsis is one of the most frequent complications of fURS however its predictive factors remain uncertain. Our objective was to assess the septic complications rates of fURS and to determinate predictive factors of these complications in patients undergoing fURS. METHODS: Our retrospective analysis included all patients admitted for any fURS for stone disease in our center from December 2009 to April 2013. Patients' medical history, urine culture, stone composition, surgical and anesthetic characteristics were collected. The primary endpoint was defined by the presence of any septic complication (i.e. postoperative fever, urosepsis, septic shock or death). We used multivariate logistic regression to assess predictive factors of septic complication related to fURS. RESULTS: Two hundred and eighty-two patients were included in this study. Urosepsis rate was 9.8% while 18.9% developed postoperative hyperthermia (>37.5°C). In multivariate analysis, the predictive risk factors of septic complication were: a neurologic disorder (OR=6.1; CI95%: 2.9-17.1), a history of urinary tract infection (UTI) (OR=19.6; CI95%: 7.3-52.1), exposure to peroperative nitrous oxide (OR=3.2; CI95%: 1.5-6.8) and intraoperative use of a laser (OR=8.0; CI95%: 13.0-30.3). CONCLUSION: The use of fURS is associated with relatively frequent septic complications. Patients with neurologic disorders or a history of UTI carry an increased risk of postoperative complications. Limitations should be drawn with the use of peroperative nitrous oxide. These results should be further validated. LEVEL OF EVIDENCE: 3. Retrospective cohort study.

Immunoglobulin genes undergo legitimate repair in human B cells not only after cis- but also frequent trans-class switch recombination.

Immunoglobulin (Ig) genes specifically recruit activation-induced deaminase (AID) for 'on-target' DNA deamination, initiating either variable (V) region somatic hypermutation, or double-strand break intermediates of class switch recombination (CSR). Such breaks overwhelmingly undergo legitimate intra-Ig repair rather than rare illegitimate and potentially oncogenic junctions outside of Ig loci. We show that in human B cells, legitimate synapsis and repair efficiently join Ig genes whether physically linked on one chromosome or located apart on both alleles. This indicates mechanisms faithfully recognizing and/or pairing loci with homology in structure and accessibility, thus licensing interchromosomal trans-CSR junctions while usually preventing illegitimate interchromosomal recombination with AID off-target genes. Physical linkage of IgH genes in cis on the same allele just increases the likelihood of legitimate repair by another fourfold. The strongest force driving CSR might thus be recognition of legitimate target genes. Formation of IgH intra-allelic loops along this process would then constitute a consequence rather than a pre-requisite of this gene-pairing process.