Establishment of a mouse model of 70% lethal dose by total-body irradiation / 한국실험동물학회지

Whereas increasing concerns about radiation exposure to nuclear disasters or side effects of anticancer radiotherapy, relatively little research for radiation damages or remedy has been done. The purpose of this study was to establish level of LD70/30 (a lethal dose for 70% of mice within 30 days) by total-body γ irradiation (TBI) in a mouse model. For this purpose, at first, 8-week-old male ICR and C57BL/6N mice from A and B companies were received high dose (10, 11, 12 Gy) TBI. After irradiation, the body weight and survival rate were monitored for 30 days consecutively. In next experiment, 5-week-old male ICR and C57BL/6N mice from B company were received same dose irradiation. Results showed that survival rate and body weight change rate in inbred C57BL/6N mice were similar between A and B company. In ICR mice, however, survival rate and body weight change rate were completely different among the companies. Significant difference of survival rate both ICR and C57BL6N mice was not observed in between 5-week-old and 8-week-old groups receiving 10 or 12 Gy TBI. Our results indicate that the strain and age of mice, and even purchasing company (especially outbred), should be matched over experimental groups in TBI experiment. Based on our results, 8-week-old male ICR mice from B company subjected to 12 Gy of TBI showed LD70/30 and suitable as a mouse model for further development of new drug using the ideal total-body irradiation model.

Sendai F/HN Viroplexes for Efficient Transfection of Leukemic T Cells

PURPOSE: Most chemical transfection reagents are ineffective for the transfection of cells in suspension, such as leukemic cell and stem cell lineages. We developed two different types of viroplexes, cationic Sendai F/HN viroplexes (CSVs) and protamine sulfate-condensed cationic Sendai F/HN viroplexes (PCSVs) for the efficient transfection of T-leukemic cells. MATERIALS AND METHODS: The viroplex systems were prepared by reconstitution of fusogenic Sendai F/HN proteins in DMKE (O,O'-dimyristyl-N-lysyl glutamate) cationic liposomes. The viroplexes were further optimized for plasmid DNA and siRNA delivery to suspension cells. The particle size and surface charge of the viroplexes were analyzed with a zeta-sizer. Transfection of plasmid DNA (pDNA) and small interfering RNA (siRNA) by CSVs or PCSV was evaluated by measurement of transgene expression, confocal microscopy, FACS, and RT-PCR. RESULTS: The optimized CSVs and PCSVs exhibited enhanced gene and siRNA delivery in the tested suspension cell lines (Jurkat cells and CEM cells), compared with conventional cationic liposomes. In the case of pDNA transfection, the CSVs and PCSVs show at least 10-fold and 100-fold higher transgene expression compared with DMKE lipoplexes (or lipofectamine 2000), respectively. The CSVs showed more effective siRNA delivery to the suspension cells than cationic liposomes, as assessed by confocal microscopy, FACS, and RT-PCR. The effective transfection by the CSVs and PCSVs is presumably due to fusogenic activity of F/HN proteins resulting in facilitated internalization of pDNA and siRNA. CONCLUSION: This study suggests that Sendai F/HN viroplexes can be widely applicable for the transfection of pDNA and siRNA to suspension cell lines.

The long-term result of condyle fracture in children

The purpose of this study was the long-term clinical and radiological evaluation of conservatively treated condylar fractures in children. This study was therefore undertaken to analyze the long-term effects of treating condylar fractures in children with conservative therapy in order to resolve the controversial question of whether complete remodeling occurs in this age or, if not, whether it is more likely to be associated with certain types of fracture or with other factors. This study was based on a series of 11 consecutive children and adolescents, aged between 3 and 15 years, with fractures of the condylar process who had been treated with conservative therapy at the Department of Oral and Maxillofacial surgery, Inha University Hospital, Inchon, Korea. All patients underwent a clinical investigation with special emphasis on Temporomandibular joint function and facial asymmetry. The patients also underwent a radiologic investigation, focusing on fracture remodeling and symmetry of mandible. It consists of panoramic radiograph, PA and lateral cephalogram and 3-D CT. No patient described impaired temporomandibular joint(TMJ) function or pain on the affected side. 2 of 8 (25%) unilateral and 1 bilateral fractures show slight facial asymmetry. Despite apparently excellent recovery of function, there were marked remodeling changes evident on the CT scan. Such changes are not usually evident on panoramic radiograph. Radiologic investigation showed incomplete remodelling(54.5%) and asymmetry of the mandible (27.3%) in some patients. Conservative treatment of condyle fracture in children results in satisfactory long-term outcome of jaw function despite a relative high frequency of radiologically noted aberrations.

The three dimensional finite element analysis of the stress distribution according to the implant and thread designs

The three dimensional finite element analysis of stress distribution in three treatment options of implant restoration for the posterior single tooth missing

The three dimensional finite element analysis of the stress distribution in the three treatment options of implants restorations for the posterior partial edentulism

In this study, three treatment options to replace two posterior missing teeth were investigated using three dimensional finite element analysis: two wide(.5.0mm) implants(the experimental model I), two standard(.3.75mm) implants(the experimental model II), and three standard(.3.75mm) implants(the experimental model III). Two kinds of load case were applied ; 1) perpendicular on occlusal surface(axial load), parallel on occlusal surface(lateral load). 2) perpendicular on occlusal surface(3mm lateral to central point). The results obtained from this study were as follows; value of on-mises stress (equivalent stress) was smallest in the two wide implant among the three experimental models. It was reported that the diameter is the efficient factor than osseointegrated surface area.

A clinical consideration of submental intubation at oral and maxillofacial surgery