Automatic analysis system of calcaneus radiograph: Rotation-invariant landmark detection for calcaneal angle measurement, fracture identification and fracture region segmentation.

BACKGROUND AND OBJECTIVE: Calcaneus is the largest tarsal bone to withstand the daily stresses of weight-bearing. The calcaneal fracture is the most common type in the tarsal bone fractures. After a fracture is suspected, plain radiographs should be taken first. Bohler's Angle (BA) and Critical Angle of Gissane (CAG), measured by four anatomic landmarks in lateral foot radiograph, can guide fracture diagnosis and facilitate operative recovery of the fractured calcaneus. This study aims to develop an analysis system that can automatically locate four anatomic landmarks, measure BA and CAG for fracture assessment, identify fractured calcaneus, and segment fractured regions. METHODS: For landmark detection, we proposed a coarse-to-fine Rotation-Invariant Regression-Voting (RIRV) landmark detection method based on regressive Multi-Layer Perceptron (MLP) and Scale Invariant Feature Transform (SIFT) patch descriptor, which solves the problem of fickle rotation of calcaneus. By implementing a novel normalization approach, the RIRV method is explicitly rotation-invariance comparing with traditional regressive methods. For fracture identification and segmentation, a convolution neural network (CNN) based on U-Net with auxiliary classification head (U-Net-CH) is designed. The input ROIs of the CNN are normalized by detected landmarks to uniform view, orientation, and scale. The advantage of this approach is the multi-task learning that combines classification and segmentation. RESULTS: Our system can accurately measure BA and CAG with a mean angle error of 3.8○ and 6.2○ respectively. For fracture identification and fracture region segmentation, our system presents good performance with an F1-score of 96.55%, recall of 94.99%, and segmentation IoU-score of 0.586. CONCLUSION: A powerful calcaneal radiograph analysis system including anatomical angles measurement, fracture identification, and fracture segmentation can be built. The proposed analysis system can aid orthopedists to improve the efficiency and accuracy of calcaneus fracture diagnosis.

Reduced weed seed shattering by silencing a cultivated rice gene: strategic mitigation for escaped transgenes.

Transgene flow form a genetically engineered (GE) crop to its wild relatives may result in unwanted environmental consequences. Mitigating transgenes via introducing a gene that is disadvantageous to wild relatives but beneficial to crops, and is tightly-linked with the target transgenes, may provide a promising solution to limit the spread of transgenes in wild/weedy populations. Here we demonstrate a novel system with significantly reduced seed shattering in crop-weed hybrid descendants by partially silenced expression of the seed-shattering gene SH4 in cultivated rice, using artificial microRNA and antisense RNA techniques. Accordingly, fewer seeds were found in the soil of the field plots where transgenic hybrid lineages were grown. However, no differences in productivity-related traits were detected between GE and non-GE cultivated rice. To silence seed-shattering genes provides a useful strategy to reduce the potential environmental impacts caused by transgene flow from commercial GE rice to weedy rice, in addition to the control of weedy rice.

Multiple tissue-specific expression of rice seed-shattering gene SH4 regulated by its promoter pSH4.

BACKGROUND: Rice seed shattering is an important domestication syndrome encoded by a gene named as SH4. The coding region of SH4 has been well studied regarding its function and roles in evolution. However, its promoter has not been identified, which limited our understanding of the detailed regulatory mechanisms of this gene. It is therefore critical to characterize the promoter and study its expression pattern. RESULTS: We analyzed the 5' upstream sequences of this gene and identified a ~2.6 kb fragment with typical promoter features, which was designated as pSH4. The promoter contained a number of cis-acting elements related to abscisic acid (ABA) and a CpG island that were characteristics of multiple tissue-specific expression. We isolated and ligated pSH4 to the ß-glucuronidase (GUS) reporter gene, and transformed it into a japonica rice cultivar to determine the multiple expression pattern of SH4. Histochemical location and fluorescence analyses of GUS activity of transgenic plants indicated multiple tissue-specific expression of pSH4 in the seed-pedicel junction region of mature panicles (with highest level), stems, coleoptiles of germinated seeds, and scutella of mature seeds. CONCLUSIONS: The multiple tissue-specific expression pSH4 is categorized as a spatiotemporal promoter that drives the expression of the SH4 gene in different rice tissues, in addition to the seed-pedicel junction region. Our findings suggest that SH4 may have additional functions in the growth and development of rice, apart from its major role in seed shattering.

[Recombinant plasmid pEGFP-AFP-TK delivered by nano-magnetic fluids targeting killed AFP positive HepG2 cells in vitro].

AIM: To study recombinant plasmid pEGFP-AFP-TK delivered by nano-magnetic fluids targeting killed AFP positive HepG2 cells in vitro. METHODS: Constructed recombinant plasmid pEGFP-AFP-TK which was delivered by nano-magnetic fluids into AFP positive HepG2 cells and AFP negative SMMC-7721.The fluorescence was detected in order to evaluate the transfection rate, and RT-PCR and Western blot were used to detect the expression of TK gene after transfection. MTT assay was used to evaluate the effect of TK on the proliferation and bystander effect of HepG2 cells in ganciclovir (GCV). Flow cytometry was used to analysis the apoptosis of HepG2 cells. RESULTS: Nano-magnetic fluids delivered plasmid pEGFP-AFP-TK into HepG2 cells and TK gene was successfully expressed, and the transfection efficacy of nano-magnetic fluids was superior to that of Lipofectamine. RT-PCR and Western blot results demonstrated that TK gene was expressed in HepG2 cells after being transfected with nano-magnetic fluids/pEGFP-AFP-TK. MTT and flow cytometry results showed TK gene exerts cell-killing and bystander effect. CONCLUSION: Nano-magnetic fluids could successfully deliver pEGFP-AFP-TK into HepG2 cells and induce expression of TK gene, which is promising gene vector for liver cancer gene therapy. AFP enhancer can specifically enhance the expression of target TK gene within the AFP positive cell, and induce bystander effect and apoptosis in the AFP positive HepG2 cell with with GCV.