Skin Preparation for Prevention of Surgical Site Infection After Cesarean Delivery: A Randomized Controlled Trial.

OBJECTIVE: To compare chlorhexidine with alcohol, povidone-iodine with alcohol, and both applied sequentially to estimate their relative effectiveness in prevention of surgical site infections after cesarean delivery. METHODS: Women undergoing nonemergent cesarean birth at greater than 37 0/7 weeks of gestation were randomly allocated to one of three antiseptic skin preparations: povidone-iodine with alcohol, chlorhexidine with alcohol, or the sequential combination of both solutions. The primary outcome was surgical site infection reported within the first 30 days postpartum. Based on a surgical site infection rate of 12%, an anticipated 50% reduction for the combination group relative to either single skin preparation group, with a power of 0.90 and an α of 0.05, 430 women per group were needed to detect a difference. RESULTS: From January 2013 to July 2014, 1,404 women were randomly assigned to one of three groups: povidone-iodine with alcohol (n=463), chlorhexidine with alcohol (n=474), or both (n=467). The groups were similar with respect to demographics, medical disorders, indication for cesarean delivery, operative time, and blood loss. The overall rate of surgical site infection-4.3%-was lower than anticipated. The skin preparation groups had similar surgical site infection rates: povidone-iodine 4.6%, chlorhexidine with alcohol 4.5%, and sequential 3.9% (P=.85). CONCLUSION: The skin preparation techniques resulted in similar rates of surgical site infections. Our study provides no support for any particular method of skin preparation before cesarean delivery. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT01870583. LEVEL OF EVIDENCE: I.

Use of vascularized periosteum or bone to improve healing of segmental allografts after tumor resection: an ovine rib model.

BACKGROUND: Despite technical advances, nonunion or delayed union remains an important clinical problem when segmental allografts are used to repair diaphyseal defects after bone tumor resection. Using an ovine rib model, the authors studied whether the addition of a vascularized periosteum or bone flap improved healing compared with a segmental allograft alone. METHODS: A 4-cm segment of rib was resected from four consecutive ribs of 15 sheep. Three different reconstructions were compared within the same sheep: allograft alone, allograft and vascularized periosteum, and allograft and vascularized bone. One defect was not reconstructed and served as a control. Five sheep were humanely killed at each of the following time points: 9, 12, and 15 weeks. The host-allograft junctions were analyzed using plain radiographs, micro-computed tomography, and histologic examination. RESULTS: Micro-computed tomographic analysis showed significant improvement with each reconstruction technique over time. Plain radiographs and histologic analyses demonstrated earlier bridging of the host-allograft junction when either vascularized periosteum or vascularized bone was used compared with allograft alone. CONCLUSION: Use of vascularized periosteum or bone may facilitate healing of the host-allograft junction after intercalary allograft reconstruction.

The C-terminal lipid-binding domain of apolipoprotein E is a highly efficient mediator of ABCA1-dependent cholesterol efflux that promotes the assembly of high-density lipoproteins.

This study was undertaken to identify the alpha-helical domains of human apoE that mediate cellular cholesterol efflux and HDL assembly via ATP-binding cassette transporter A1 (ABCA1). The C-terminal (CT) domain (residues 222-299) of apoE was found to stimulate ABCA1-dependent cholesterol efflux in a manner similar to that of intact apoE2, -E3, and -E4 in studies using J774 macrophages and HeLa cells. The N-terminal (NT) four-helix bundle domain (residues 1-191) was a relatively poor mediator of cholesterol efflux. On a per molecule basis, the CT domain stimulated cholesterol efflux with the same efficiency (Km approximately 0.2 microM) as intact apoA-I and apoE. Gel filtration chromatography of conditioned medium from ABCA1-expressing J774 cells revealed that, like the intact apoE isoforms, the CT domain promoted the assembly of HDL particles with diameters of 8 and 13 nm. Removal of the CT domain abolished the formation of HDL-sized particles, and only larger particles eluting in the void volume were formed. Studies with CT truncation mutants of apoE3 and peptides indicated that hydrophobic helical segments governed the efficiency of cellular cholesterol efflux and that conjoined class A and G amphipathic alpha-helices were required for optimal efflux activity. Collectively, the data suggest that the CT lipid-binding domain of apoE encompassing amino acids 222-299 is necessary and sufficient for mediating ABCA1 lipid efflux and HDL particle assembly.