MicroRNA-572 Improves Early Post-Operative Cognitive Dysfunction by Down-Regulating Neural Cell Adhesion Molecule 1

Post-operative cognitive dysfunction (POCD) is a commonly-seen postoperative complication in elderly patients. However, the underlying mechanisms of POCD remain unclear. miRNAs, which are reported to be involved in the pathogenesis of the nervous system diseases, may also affect POCD. In this study, miRNA microarray technology was used to analyze the circulating miRNA expression profile of POCD patients. Among the altered miRNAs, miR-572 had the greatest decrease, which was also verified in vivo in rat POCD model. Further analysis found that miR-572 could regulate the expression of NCAM1 in the hippocampal neurons and interfering miR-572 expression could facilitate the restoration of cognitive function in vivo. Moreover, clinical correlation analysis found that the miR-572 expression was associated with the incidence of POCD. Collectively, miR-572 is involved in the development and restoration of POCD and it may serve as a biological marker for early diagnosis of POCD.     

Adaptive Tensor-Based Principal Component Analysis for Low-Dose CT Image Denoising

Computed tomography (CT) has a revolutionized diagnostic radiology but involves large radiation doses that directly impact image quality. In this paper, we propose adaptive tensor-based principal component analysis (AT-PCA) algorithm for low-dose CT image denoising. Pixels in the image are presented by their nearby neighbors, and are modeled as a patch. Adaptive searching windows are calculated to find similar patches as training groups for further processing. Tensor-based PCA is used to obtain transformation matrices, and coefficients are sequentially shrunk by the linear minimum mean square error. Reconstructed patches are obtained, and a denoised image is finally achieved by aggregating all of these patches. The experimental results of the standard test image show that the best results are obtained with two denoising rounds according to six quantitative measures. For the experiment on the clinical images, the proposed AT-PCA method can suppress the noise, enhance the edge, and improve the image quality more effectively than NLM and KSVD denoising methods.     

Serum- and Glucocorticoid-Inducible Kinase-1 (SGK-1) Plays a Role in Membrane Trafficking in Caenorhabditis elegans

The mammalian serum- and glucocorticoid-inducible kinase SGK1 regulates the endocytosis of ion channels. Here we report that in C. elegans sgk-1 null mutants, GFP-tagged MIG-14/Wntless, the sorting receptor of Wnt, failed to localize to the basolateral membrane of intestinal cells; instead, it was mis-sorted to lysosomes. This effect can be explained in part by altered sphingolipid levels, because reducing glucosylceramide biosynthesis restored the localization of MIG-14::GFP. Membrane traffic was not perturbed in general, as no obvious morphological defects were detected for early endosomes, the Golgi apparatus, and the endoplasmic reticulum (ER) in sgk-1 null animals. The recycling of MIG-14/Wntless through the Golgi might be partially responsible for the observed phenotype because the subcellular distribution of two plasma membrane cargoes that do not recycle through the trans-Golgi network (TGN) was affected to a lesser degree. Consistently, knockdown of the ArfGEF gbf-1 altered the distribution of SGK-1 at the basolateral membrane of intestinal cells. In addition, we found that sgk-1(RNAi) induced unfolded protein response in the ER, suggesting at least an indirect role of SGK-1 early in the secretory pathway. We propose that SGK-1 function is required for lipid homeostasis and that it acts at different intracellular trafficking steps.     

Comprehensive Comparison of Three Different Immunosuppressive Regimens for Liver Transplant Patients with Hepatocellular Carcinoma: Steroid-Free Immunosuppression,Induction Immunosuppression and Standard Immunosuppression

The different choices of immunosuppression (IS) regimens influenced the outcomes of liver transplantation. Steroid was applied as a standard IS to prevent and treat rejections. However, steroid-related complications were increasingly prominent. This study compared the efficacy and safety of standard IS regimens with the efficacy and safety of steroid-free IS regimen and induction IS regimen in Chinese liver transplantation recipients for hepatocellular carcinoma (HCC). A total of 329 patients who underwent liver transplantation from January 2008 to December 2012 were retrospectively reviewed. Three different groups of patients received standard triple-drug IS regimen of steroid, tacrolimus (TAC) and mycophenolate mofetil (MMF) (triple-drug regimen group; n=57), induction-contained IS regimen of basiliximab, steroid, TAC and MMF (BS group; n=241), and induction-contained and steroid-free regimen of basiliximab, TAC and MMF (SF group; n=31), respectively. There were no significant differences in terms of patient, tumor-free and graft survival rates. The acute rejection rate and rejection time were equivalent in different groups. But compared with BS group, higher incidences of biliary complications (11.52% vs. 30.77%, p=0.013) and graft dysfunction (0.48% vs. 13.64%, p=0.003) were observed in SF group. Furthermore, compared with the two groups, incidence of pleural effusion was also higher in SF group (15.79%, 11.96% vs. 45.45%, respectively, both p<0.01). And a trend towards less proportion of De novo diabetes was revealed in SF group. Although it was found that patient, tumor-free and graft survival rates were equivalent among three IS regimens, higher incidences of complications were demonstrated in steroid-free regimen in patients for HCC. These findings suggested that steroid-free IS regimen has no clear advantages in comparison with standard IS regimens for liver transplant recipients with HCC and the postoperative complications should be treated with concentrated attention.     

Dynamics of Maize Carbon Contribution to Soil Organic Carbon in Association with Soil Type and Fertility Level

Soil type and fertility level influence straw carbon dynamics in the agroecosystems. However, there is a limited understanding of the dynamic processes of straw-derived and soil-derived carbon and the influence of the addition of straw carbon on soil-derived organic carbon in different soils associated with different fertility levels. In this study, we applied the in-situ carborundum tube method and ¹³C-labeled maize straw (with and without maize straw) at two cropland (Phaeozem and Luvisol soils) experimental sites in northeast China to quantify the dynamics of maize-derived and soil-derived carbon in soils associated with high and low fertility, and to examine how the addition of maize carbon influences soil-derived organic carbon and the interactions of soil type and fertility level with maize-derived and soil-derived carbon. We found that, on average, the contributions of maize-derived carbon to total organic carbon in maize-soil systems during the experimental period were differentiated among low fertility Luvisol (from 62.82% to 42.90), high fertility Luvisol (from 53.15% to 30.00%), low fertility Phaeozem (from 58.69% to 36.29%) and high fertility Phaeozem (from 41.06% to 16.60%). Furthermore, the addition of maize carbon significantly decreased the remaining soil-derived organic carbon in low and high fertility Luvisols and low fertility Phaeozem before two months. However, the increasing differences in soil-derived organic carbon between both soils with and without maize straw after two months suggested that maize-derived carbon was incorporated into soil-derived organic carbon, thereby potentially offsetting the loss of soil-derived organic carbon. These results suggested that Phaeozem and high fertility level soils would fix more maize carbon over time and thus were more beneficial for protecting soil-derived organic carbon from maize carbon decomposition.     

Histone Chaperone-Mediated Nucleosome Assembly Process

A huge amount of information is stored in genomic DNA and this stored information resides inside the nucleus with the aid of chromosomal condensation factors. It has been reported that the repeat nucleosome core particle (NCP) consists of 147-bp of DNA and two copies of H2A, H2B, H3 and H4. Regulation of chromosomal structure is important to many processes inside the cell. In vivo, a group of histone chaperones facilitate and regulate nucleosome assembly. How NCPs are constructed with the aid of histone chaperones remains unclear. In this study, the histone chaperone-mediated nucleosome assembly process was investigated using single-molecule tethered particle motion (TPM) experiments. It was found that Asf1 is able to exert more influence than Nap1 and poly glutamate acid (PGA) on the nucleosome formation process, which highlights Asf1’s specific role in tetrasome formation. Thermodynamic parameters supported a model whereby energetically favored nucleosomal complexes compete with non-nucleosomal complexes. In addition, our kinetic findings propose the model that histone chaperones mediate nucleosome assembly along a path that leads to enthalpy-favored products with free histones as reaction substrates.     

Evaluation of Four Commonly Used DNA Barcoding Loci for Chinese Medicinal Plants of the Family Schisandraceae

Many species of Schisandraceae are used in traditional Chinese medicine and are faced with contamination and substitution risks due to inaccurate identification. Here, we investigated the discriminatory power of four commonly used DNA barcoding loci (ITS, trnH-psbA, matK, and rbcL) and corresponding multi-locus combinations for 135 individuals from 33 species of Schisandraceae, using distance-, tree-, similarity-, and character-based methods, at both the family level and the genus level. Our results showed that the two spacer regions (ITS and trnH-psbA) possess higher species-resolving power than the two coding regions (matK and rbcL). The degree of species resolution increased with most of the multi-locus combinations. Furthermore, our results implied that the best DNA barcode for the species discrimination at the family level might not always be the most suitable one at the genus level. Here we propose the combination of ITS+trnH-psbA+matK+rbcL as the most ideal DNA barcode for discriminating the medicinal plants of Schisandra and Kadsura, and the combination of ITS+trnH-psbA as the most suitable barcode for Illicium species. In addition, the closely related species Schisandra rubriflora Rehder & E. H. Wilson and Schisandra grandiflora Hook.f. & Thomson, were paraphyletic with each other on phylogenetic trees, suggesting that they should not be distinct species. Furthermore, the samples of these two species from the southern Hengduan Mountains region formed a distinct cluster that was separated from the samples of other regions, implying the presence of cryptic diversity. The feasibility of DNA barcodes for identification of geographical authenticity was also verified here. The database and paradigm that we provide in this study could be used as reference for the authentication of traditional Chinese medicinal plants utilizing DNA barcoding.