Objective To investigate the expression and biological function of miRNA-449 a in lung cancer . Methods A case-control study was conducted in 58 patients diagnosed with lung cancer ( carcinoma and adeno-carcinoma) and normal tissue closely adjacent to tumor.MiRNA-449a simulation was designed and synthesized, was dissolved into two different concentrations as 10 and 20 mg/mL.The expression of miRNA-449a in lung cancer tissues and matched normal tissues were detected by Real time PCR .The expression of luciferase gene was detected by chemiluminescence technique.MiRNA-449a mimics on cell apoptosis was evaluated by MTT assay . Results The mean tissues expression levels of miRNA-449 a in squamous carcinoma group and adenocarcinoma group were 1.48 ±1.63 and 1.52 ±1.54 respectively, and were significantly lower than in control group (2.74 ± 1.55 ) ( P<0.01 ) .The average intensity of fluorescent protein in 10 mg/mL group and 20 mg/mL group were 2 115 ±168 and 1 352 ±159 respectively , and were significantly lower than that in control group ( 4 975 ±115 ) ( P<0.01 ) .Conclusions MiRNA-449 a was down-regulated expression in lung cancer and induced apoptosis .

OBJECTIVE: To investigate the effect of orthodontic traction on the microstructure of dental enamel. METHODS: Forty-eight isolated premolars were randomly divided into 6 groups (=8), including Group A (blank control group), in which the teeth were bonded with the orthodontic brackets without any loading force; Groups B1, B2, and B3 where the teeth were bonded with the orthodontic brackets using clinical adhesives and loaded with 50 g force for 6 months, 200 g force for 6 months, and 200 g force for 1 month, respectively; and Groups C1 and C2, where the teeth were bonded with straight wire brackets using light curing bonding and chemical curing bonding techniques, respectively. All the teeth were embedded with non-decalcified epoxy resin. Scanning electron microscope (SEM), atomic force microscope (AFM), and energy spectrometer (EDS) were used to analyze interface morphology and elemental composition of the teeth sliced with a hard tissue microtome. RESULTS: Compared with those in Group A, the teeth in the other 5 groups showed increased adhesive residue index with microcracks and void structures on the enamel surface under SEM; AFM revealed microcracks on the enamel surface with angles to the grinding direction. A larger loading force on the bracket resulted in more microcracks on the enamel interface. The interface roughness differed significantly between Groups A and C2, and the peak-to-valley distance differed significantly between Groups A, C, and C2. CONCLUSIONS Orthodontic traction can cause changes in the microstructure of normal dental enamel.
Dental Enamel ; Materials Testing ; Orthodontic Brackets ; Resin Cements ; Surface Properties ; Traction