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BACKGROUND: superparamagnetic ferric oxide nanoparticle exhibits small diameter, good water solubility, histocompatibility, superparamagnetism and surface area effect, allowing the application in nuclear magnetic resonance and biomacromolecule as carriers. OBJECTIVE: To construct superparamagnetic iron oxide nanoparticles coated by dextran (DCIONP), determine its physical and magnetic properties and evaluate the magnetic properties of tumor cells labeled by DCIONP in vitro. METHODS: The DCIONP was obtained by means of classical coprecipitation in dextran solution. Its size was determined by the transmission electron microscopy, and the crystal formation in DCIONP was measured by X-ray diffraction analysis. T2 values as well as relaxation rate were evaluated with a 1.5T MR system. After ostecsarcoma cell line MG63, hepatocellular carcinoma cell line HGP2 and rat bone marrow-derived mesenchymal cells were labeled by DCIONP in vitro, the perls blue staining and the transmission electron microscopy were performed to observe intracellular iron. In addition, the change of magnetic signal intensity was measured by 1.5T MR. RESULTS AND CONCLUSION: The iron size was 10 nm and the formation of Fe_3O_4 crystal in DCIONP was confirmed by X-ray diffraction analysis. These nanoparticles possessed some characteristic of superparamagnetic and showed the spin-spin relaxation rate of 3.936×10~6 mol/s. After three kinds of cells were labeled by DCIONP, the nanoparticles were mainly located in nucleus, and partially in cytoplasm confirmed. The spin-spin relaxations were shortened gradually compared with increasing labeled cells. Obvious magnetic attenuation was measured at 2×10~9/L and 2×10~(10)/L labeled cells. Results show that the prepared nanoparticle with stable physical and magnetic prosperities was developed, and it is able to product characteristic magnetic attenuation on the magnetic labeled tumor cells by 1.5T MR.
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Objective To construct the human osteoblast-like cell model with estrogen receptor α(ERα)subunit gene knocked down. Methods According to the computer-aided design(CAD),ERα-specific small interference RNA(siRNA)gene was synthesized and cloned into the expression vector pSilencer 4.1-CMV. The recombinant ERα siRNA plasmid was transfected into human osteoblast-like cell line MG63 by lipofectin,the cloned MG63 ceils were selected by hygromycin,and the cloned MG63 cell was cultured more than 20 passages after transfection.The expression of ERα mRNA in MG63 cells was detected by reverse transcription-polymerase chain reaction(RT-PCR).The expression and location of ERα protein were identified by immunocytochemistry.Compared with control groups,proliferation rate,growth cycle and expression did not show significant difference.Results The recombinant eukaryote plasmid vector was constructed.Furthermore,the recombinant plasmid knocked down ERα protein in human osteoblast-like cells. Conclusions The human osteoblast-like cell model with RNAi-knocked down ERα gene is constructed successfully.This model appears to be very useful for the future research on ERα biological characters and on molecular mechanism of bone metabolism.
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Objective To investigate the effect of T149-C and A163-G polymorphism of osteoprotegerin promoter region combined with low-body weight on bone mineral density (BMD) of postmenopausal osteoporosis women and postmenopausal healthy women. Methods Seventy-three postmenopausal osteoporosis women and 61 postmenopausal healthy women were enrolled. The shifted patterns were searched from randomly selected 25 samples by SSCP-PCR and their sequences were determined by cycle sequencing. The T149-C and A163-G polymorphisms were determined by PCR-RFLP. BMD of lumbar spines and femoral neck, Ward and trochanteric areas were measured by dual energy X-ray absorptiometry. Results T149-C and A163-G polymorphisms in the postmenopausal osteoporosis women and the postmenopausal healthy women were through Hardy Weinberg equilibrium. Both single and combined genotype frequencies of the T149-C and A163-G polymorphism did not show any difference between postmenopausal osteoporosis women and postmenopausal healthy women. The BMD levels of the postmenopausal osteoporosis women were significantly lower than those of the postmenopausal healthy women in lumbar spines and femoral neck, and BMI levels of the postmenopausal osteoporosis women was significantly lower than those of the postmenopausal healthy women. Conclusions The T149-C and A163-G polymorphism has no synergistic effect on bone mass in both the postmenopausal osteoporosis women and the postmenopausal healthy women. The single and combined genotypes of the T149-C and A163-G polymorphism may not be used as genetic markers in predicting their risk of developing osteoporosis in Chinese women of the Han nationality, but may be susceptible gene of osteoporosis.
