To train the innovation ability of postgraduates is a major goal in postgradu-ates'education. With the practical experience in train master's degree in medical imaging and nuclear medical,we think that developing basic and clinical research in molecular imaging field,can increase the quality and innovation ability of the postgraduates.

The present paper is aimed to detect superparamagnetic iron oxide labeled c-erbB2 oncogene antisense oligonucleotide probe (magnetic antisense probe) connected with SK-Br-3 oncocyte mRNA nucleotide by high resolution atomic force microscope (AFM). We transfected SK-Br-3 oncocyte with magnetic antisense probe, then observed the cells by AFM with high resolution and detected protein expression and magnetic resonance imagine (MRI). The high resolution AFM clearly showed the connection of the oligonucleotide remote end of magnetic antisense probe with the mRNA nucleotide of oncocyte. The expression of e-erbB2 protein in SK-Br3 cells were highly inhibited by using magnetic antisense probe. We then obtained the lowest signal to noise ratio (SNR) of SK-Br-3 oncocyte transfected with magnetic antisense probe by MRI (P<0.05). These experiments demonstrated that the high resolution AFM could be used to show the binding of magnetic antisense probe and SK-Br-3 mRNA of tumor cell nuclear.
Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; DNA, Antisense ; chemistry ; genetics ; Female ; Ferric Compounds ; chemistry ; Genes, erbB-2 ; genetics ; Humans ; Magnetics ; Microscopy, Atomic Force ; methods ; Molecular Probe Techniques ; Nucleic Acid Probes ; chemistry ; genetics ; Oligodeoxyribonucleotides ; chemistry ; genetics ; Oxyphil Cells ; ultrastructure ; RNA, Messenger ; genetics ; metabolism

OBJECTIVETo determine the optimal concentration of c-erbB2 antisense probe labeled with superparamagnetic iron oxide (SPIO) nanoparticles for in vivo tumor imaging in mice using magnetic resonance imaging (MRI).

METHODSThirty BALB/c mice bearing SK-Br-3 tumor were randomized into 5 groups to receive injections of different concentrations of SPIO-labeled c-erbB2 antisense probe (containing 6.0, 9.0, 12.0, 15.0, or 18.0 mg Fe/kg). MRI was performed before and 6 h after the injections, and the signal intensities of the tumor were compared among the groups. The tumor tissues were then dissected for microscopic examination with HE and Prussian blue staining.

RESULTSThe tumor-bearing mice all survived after injections of the probe at doses of 6.0, 9.0 and 12.0 mg, but injections at higher doses (15.0 and 18.0 mg) caused death in some mice. Injections of the probe at the doses of 12.0, 15.0 and 18.0 mg resulted in significant signal enhancement of the tumor (P<0.001) to allow visual identification, but the changes showed no significant differences among the 3 groups (P>0.05). Pathological examination revealed irregular structures of the tumor issue containing numerous heterogeneous tumor cells aligned into cancer nests; Prussian blue staining visualized scattered blue iron particles in the tumor issue, which was especially obvious in mice injected with 12.0, 15.0 and 18.0 mg labeled probe.

CONCLUSIONInjection of 12.0 mg/kg SPIO-labeled c-erbB2 antisense probe allows optimal tumor imaging in BALB/c mice using MRI.

Animals ; Antisense Elements (Genetics) ; Cell Line, Tumor ; Contrast Media ; Dextrans ; Genes, erbB-2 ; Magnetic Resonance Imaging ; Magnetite Nanoparticles ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Nanoparticles ; Nucleic Acid Probes ; genetics ; Xenograft Model Antitumor Assays