Coupled mutagenesis screens and genetic mapping in zebrafish.

Forward genetic analysis is one of the principal advantages of the zebrafish model system. However, managing zebrafish mutant lines derived from mutagenesis screens and mapping the corresponding mutations and integrating them into the larger collection of mutations remain arduous tasks. To simplify and focus these endeavors, we developed an approach that facilitates the rapid mapping of new zebrafish mutations as they are generated through mutagenesis screens. We selected a minimal panel of 149 simple sequence length polymorphism markers for a first-pass genome scan in crosses involving C32 and SJD inbred lines. We also conducted a small chemical mutagenesis screen that identified several new mutations affecting zebrafish embryonic melanocyte development. Using our first-pass marker panel in bulked-segregant analysis, we were able to identify the genetic map positions of these mutations as they were isolated in our screen. Rapid mapping of the mutations facilitated stock management, helped direct allelism tests, and should accelerate identification of the affected genes. These results demonstrate the efficacy of coupling mutagenesis screens with genetic mapping.

Comparison of long-term incidence of posterior capsular opacification between phacoemulsification and phacotrabeculectomy.

PURPOSE: To investigate the long-term incidence of posterior capsular opacification after phacoemulsification compared with phacotrabeculectomy with or without adjunctive subconjunctival mitomycin C. METHODS: This was a retrospectively conducted long-term, observational, case-control study. One hundred eyes of 100 cataract patients who underwent phacoemulsification and posterior chamber intraocular lens implantation and 100 eyes of 100 primary open-angle glaucoma patients with cataract that underwent phacotrabeculectomy and posterior chamber intraocular lens implantation, matched with respect to age, intraocular lens type, prevalence of diabetes mellitus, and length of follow-up. The main outcome measure was the rate of clinically significant posterior capsular opacification as determined by slit-lamp biomicroscopy and necessity to perform neodynium:yttrium aluminum garnet (Nd:YAG) capsulotomy and as calculated by Kaplan-Meier survival analysis. Postoperative visual acuity and maintenance of intraocular pressure control were also measured. RESULTS: There was no significant difference in the rate of posterior capsular opacification requiring Nd:YAG capsulotomy between the phacoemulsification and phacotrabeculectomy groups (P =.77). However, a significant difference in the rate of posterior capsular opacification was found between those patients without diabetes mellitus and those with a preoperative diagnosis of diabetes mellitus (P =.016). Also, survival analysis comparing use of mitomycin C with no use of mitomycin C in the phacotrabeculectomy group showed a higher survival in the mitomycin C subgroup (P =.03). CONCLUSION: There was no significant difference in long-term posterior capsular opacification between phacoemulsification and phacotrabeculectomy in the study population. Intraoperative, adjunctive use of mitomycin C in the phacotrabeculectomy group and the presence of diabetes mellitus in the overall patients were beneficial (protective) factors against posterior capsular opacification.