Short-term chilled storage of zebrafish (Danio rerio) embryos in cryoprotectant as an alternative to cryopreservation.

As zebrafish embryos have never been cryopreserved, we developed a protocol to store zebrafish embryos (50% epiboly-5.3 hour post fertilization) for up to 18 h at 0°C. Initial experiments to optimize the cryoprotectant (CPA) solution demonstrated improved embryo hatching rate following chilling at 0°C for 18 h with 1 M MeOH+0.1 M sucrose (56 ± 5%) compared with other combinations of methanol (0.2-0.5 M) and sucrose (0.05-0.1 M). This combination of CPAs that protects against chilling injury was further tested to assess its impact on sox gene and protein expression. Significant decreases in sox3 gene expression were observed in hatched embryos that had been chilled for 18 h in 1 M MeOH+0.1 sucrose compared with non-chilled controls, however the expression of both sox2 and sox3 proteins was unaffected. Significant decreases in sox2 protein expression were, however, observed in embryos that had been chilled without CPAs and these embryos also had lower hatching rates than those chilled with the optimal CPA solution. We, therefore, conclude that the CPA combination of 1 M MeOH+0.1 M sucrose facilitates chilled storage of early stage (50% epiboly) zebrafish embryos for up to 18 h without compromising transcriptional response

Technical complications of implant-supported fixed partial dentures in partially edentulous cases after an average observation period of 5 years

OBJECTIVES: The purpose of this prospective long-term study was to evaluate the incidence of the most common technical problems, namely screw loosening, screw fracture, fracturing of veneering porcelain and framework fracture in implant-supported fixed partial dentures (FPDs), and assess the survival and success rate (event-free survival) after 5 years of function. MATERIALS AND METHODS: In 76 partially edentulous patients, a total of 205 3i-implants (machined surface) were placed and restored with 112 implant-supported FPDs (46 single crowns, 81 splinted crowns, seven FPD bridges and 23 FPDs with cantilevers). The survival rate of FPDs supported by implants was 94.5% (CI-95: 90.1-98.8) after an average observation period of 5 years. The success rate (event-free survival) of the FPDs was 80% (CI-95: 87.3-72.7). After an observation period of 5 years the cumulative incidence of screw loosening was 6.7% (CI-95: 1.8-11.5), the cumulative incidence for screw fracture was 3.9% (CI-95: 0.1-7.7). Fracture of the veneering porcelain occurred in 5.7% (CI-95: 1.2-10.2) of all FPDs. Fracturing of the suprastructure framework was rare (1%; CI-95: 0-2.9). The overall complication incidence after 5 years was highest in the group of FPDs with cantilever, which showed the lowest success rate 68.6% (CI-95: 50-87.3), followed by single crowns (77.6%; CI-95: 53.3-100) and splinted crowns (86.1%; CI-95: 59.5-100). No complication occurred in FPD bridges. CONCLUSION: Fixed partial dentures supported by 3i-implants showed low technical complications rates, the most common being loosening of the abutment screw. Managing these complications can cause extra amount of chair-side time and patient dissatisfaction