Present work was designed to quantitatively evaluate the performance of diffusion-weighted magnetic resonance imaging (DWI) in the diagnosis of the presence of metastasis in lymph nodes (LNs).Eligible studies were identified from systematical PubMed and EMBASE searches.Data were extracted.Meta-analyses were performed to generate pooled sensitivity and specificity on the basis of per-node,per-lesion and per-patient,respectively.Fourteen publications (2458 LNs,404 lesions and 334 patients) were eligible.Per-node basis demonstrated the pooled sensitivity and specificity was 0.82 (P＜0.0001) and 0.90 (P＜0.0001),respectively.Per-lesion basis illustrated the pooled sensitivity and specificity was 0.73 (P=-0.0036) and 0.85 (P＜0.0001),respectively.Per-patient basis indicated the pooled sensitivity and specificity was 0.67 (P=0.0909) and 0.86 (P＜0.0001),respectively.In conclusion,DWI has rather a negative predictive value for the diagnosis of LN metastasis presence.The difference of the mean apparent diffusion coefficients between benign and malignant LNs is not yet stable.Therefore,the DWI technique has to be further improved.

AIM:To evaluate the effect of α2-macroglobulin(α2M) against X-ray induced obstacle on osteo-genic differentiation of human bone marrow mesenchymal stem cells(hBMMSCs). METHODS:hBMMSCs were cultured in vitro. The 4th generation of hBMMSCs was irradiated with 8 Gy X-ray,then induced osteogenic differentiation and trea-ted with different concentrations of α2M(0.5 and 1.0 g/L). The alkaline phosphatase(ALP) activity and the mRNA ex-pression of runt-related transcription factor-2 (RUNX2) were detected on day 7 after osteogenic induction. The protein ex-pression of osteoglycin (OGN) was evaluated by Western blot on day 14 after osteogenic induction. The formation of calci-um nodules was detected by alizarin red staining on day 21 after osteogenic induction. The activity of superoxide dismutase (SOD) and the protein expression of MnSOD of irradiated hBMMSCs with 8 Gy X-ray were determined at 24 h after α2M treatment. RESULTS:Compared with 8 Gy X-ray group,the activity of ALP,the mRNA expression of RUNX2,the pro-tein expression of OGN and MnSOD,as well as SOD activity were higher than those in the hBMMSCs treated with α2M at 0.5 and 1.0 g/L after 8 Gy X-ray irradiation,and the calcium nodules were also increased. CONCLUSION:α2M signifi-cantly improves the osteogenic differentiation ability,the SOD activity and MnSOD protein expression of hBMMSCs after ra-diation injury.