Comparison of Magnetic Resonance Elastography and Diffusion-weighted Imaging for Staging Hepatic Fibrosis

Background：To compare the diagnostic values of magnetic resonance elastography （MRE） and diffusion-weighted imaging （DWI） in staging hepatic fibrosis （HF） in an animal model.Methods：This study consisted of 44 rabbits served as HF group and 9 normal rabbits.HF group was divided into two subgroups：Group A （n =32） and Group B （n =12）.Rabbits in Group B were served as a complementary group when rabbits in Group A suddenly died during the study.Rabbits from control and Group A underwent abdominal MR imaging （MRI）,MRE,and DWI.In Group A,random eight rabbits underwent MRI examinations at 4,5,6,l0 weeks after carbon tetrachloride oil subcutaneous injection.Liver stiffness （LS） and apparent diffusion coefficient （ADC） values of liver parenchyma were measured.The diagnostic performance of MRE and DWI for staging HF was compared using the receiver operating characteristic curve analysis on the basis of the histopathological analysis of HF.Results：Significant differences of LS and DWI values were present among HF stages （P 〈 0.005）.The LS values measured on MRE （r =0.838,P 〈 0.001） were more strongly correlated with the HF stages than with ADC values （r =-0.527,P 〈 0.001）.The area under the receiver operating characteristic curve values of LS were significantly larger than those of DWI were for discriminating two stages of HF （0.979 vs.0.712 for ≥ S 1,0.922 vs.0.699 for ≥ S2）.MRE showed higher specificity for predicting all stages of HF compared to DWI.Conclusions：MRE more strongly correlated with the HF stages than DWI and is more specific in predicting all HF stages.

Advances in Transcriptomic Studies and Ginsenoside Biosynthesis of American Ginseng

American ginseng（Panax quinquefolius L.）, belonging to the Araliaceae family, is one of the most widely used traditional herbs in the world. Its major bioactive constituents are triterpene saponins known as ginsenosides. Up to date, it is still a big challenge to sequence and assemble the large and repeat-enriched genome of tetraploid American ginseng, using whole genome shotgun（WGS） sequencing strategy. The lack of American ginseng genome information has significantly impeded its genetic and functional genomic studies. With the development of next-generation sequencing（NGS） technologies, sequencing and analysis of transcriptomes have become powerful tools for the discovery of novel genes and elucidation of specific biosynthetic pathways of secondary metabolites. Here we summarized the recent advances in the transcriptomic studies of American ginseng, including high-throughput transcriptome sequencing, assembly, and functional gene annotation and classification. Based on the results of transcriptomic data mining and co-expression analyses, many candidate genes possibly involved in the biosynthetic pathway of ginsenosides have been found, thereby providing an unparalleled opportunity to fully understand the mechanism of ginsenoside biosynthesis and its regulations in American ginseng. Advances in transcriptomic studies will contribute to the molecular breeding and planting management of American ginseng and to the development of novel ginsenoside-type drugs.