Improving abdomen tumor low-dose CT images using a fast dictionary learning based processing.

International audienceIn abdomen computed tomography (CT), repeated radiation exposures are often inevitable for cancer patients who receive surgery or radiotherapy guided by CT images. Low-dose scans should thus be considered in order to avoid the harm of accumulative x-ray radiation. This work is aimed at improving abdomen tumor CT images from low-dose scans by using a fast dictionary learning (DL) based processing. Stemming from sparse representation theory, the proposed patch-based DL approach allows effective suppression of both mottled noise and streak artifacts. The experiments carried out on clinical data show that the proposed method brings encouraging improvements in abdomen low-dose CT images with tumors

Circulating exo-miR-154-5p regulates vascular dementia through endothelial progenitor cell-mediated angiogenesis

BackgroundVascular dementia (VaD) mainly results from cerebral vascular lesions and tissue changes, which contribute to neurodegenerative processes. Effective therapeutic approaches to targeting angiogenesis may reduce mortality of VaD. Endothelial progenitor cells (EPCs) play a key role in postnatal angiogenesis. Many exosomal microRNAs (exo-miRNAs) have been reported to involve in the development of dementia. The present study was designed to investigate whether the expression profile of the exo-miRNAs is significantly altered in patients with VaD and to reveal the function of differentially expressed miRNAs and the relevant mechanisms in EPC-mediated angiogenesis in VaD rat model.ResultsExosomes isolated from serum of patients with VaD (n = 7) and age-matched control subjects (n = 7), and miRNA sequencing and bioinformatics analysis found that circulating exosome miRNA-155-5p, miRNA-154-5p, miR-132-5p, and miR-1294 were upregulated in patients with VaD. The expression of miRNA-154-5p was further verified to be upregulated in clinical samples (n = 23) and 2-vessel occlusion-induced VaD rat model by reverse transcription quantitative PCR (RT-qPCR). Notably, miRNA-154-5p inhibition in bone marrow-EPCs (BM-EPCs) from VaD rats improved EPC functions, including tube formation, migration, and adhesion, and elevated concentrations of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α). The mRNA levels of ICAM-1, VCAM-1, and MCP-1 were reduced in miRNA-154-5p-inhibited EPCs. In addition, miRNA-154-5p inhibition increased the level of superoxide dismutase (SOD), and decreased reactive oxygen species (ROS) in EPCs. PRKAA2 was chosen as a promising target gene of miR-154-5p, and miRNA-154-5p inhibition upregulated the protein expression of AMPKα2. Furthermore, upregulation of miR-154-5p markedly diminished EPC functions and inhibited angiogenesis following EPC transplantation in VaD rats.ConclusionCirculating exo-miR-154-5p was upregulated in patients with VaD, and miR-154-5p upregulation was associated with impaired EPC functions and angiogenesis in VaD rat model. Therefore, miR-154-5p is a promising biomarker and therapeutic strategy for VaD

A nonalcoholic fatty liver disease cirrhosis model in gerbil:the dynamic relationship between hepatic lipid metabolism and cirrhosis

Nonalcoholic fatty liver disease (NAFLD) usually takes decades to develop into cirrhosis, which limits the longitudinal study of NAFLD. This work aims at developing a NAFLD-caused cirrhosis model in gerbil and examining the dynamic relationship between hepatic lipid metabolism and cirrhosis. We fed gerbil a high-fat and high-cholesterol diet (HFHCD) for 24 weeks, and recorded the gerbil's phenotype at 3, 6, 9, 12, 15, 18, 21, 24 weeks. The model's pathological process, lipid metabolism, oxidative stress, liver collagen deposition and presence of relevant cytokines were tested and evaluated during the full-time frame of disease onset. The gerbil model can induce nonalcoholic steatohepatitis (NASH) within 9 weeks, and can develop cirrhosis after 21 weeks induction. The model's lipids metabolism disorder is accompanied with the liver damage development. During the NAFLD progression, triglycerides (TG) and free fatty acids (FFA) have presented distinct rise and fall tendency, and the turning points are at the fibrosis stage. Besides that, the ratios of total cholesterol (CHO) to high-density lipoprotein cholesterol (HDL-C) exhibited constant growth tendency, and have a good linear relationship with hepatic stellate cells (HSC) (R-2 = 0.802, P <0.001). The gerbil NAFLD cirrhosis model has been developed and possesses positive correlation between lipids metabolism and cirrhosis. The compelling rise and fall tendency of TG and FFA indicated that the fibrosis progression can lead to impairment in lipoprotein synthesis and engender decreased TG level. CHO/HDL-C ratios can imply the fibrosis progress and be used as a blood indicator for disease prediction and prevention

[Photograph 2012.201.B1048.0785]

Photograph used for a story in the Oklahoma Times newspaper. Caption: "CAN TOU GIN ZEKE?