TRIM5α recruits HDAC1 to p50 and Sp1 and promotes H3K9 deacetylation at the HIV-1 LTR.

Tripartite motif-containing protein 5α (TRIM5α) is generally known to block the postentry events of HIV-1. Here, we report an uncharacterized role for TRIM5α in the maintenance of viral latency. Knockdown of TRIM5α potentiates the transcription of HIV-1 in multiple latency models, which is reversed by shRNA-resistant TRIM5α. TRIM5α suppresses TNFα-activated HIV-1 LTR-driven as well as NF-κB- and Sp1-driven gene expression, with the RING and B-box 2 domains being the essential determinants. Mechanistically, TRIM5α binds to and enhances the recruitment of histone deacetylase 1 (HDAC1) to NF-κB p50 and Sp1. ChIP‒qPCR analyses further reveal that the association of TRIM5α with HIV-1 LTR induces HDAC1 recruitment and local H3K9 deacetylation. Conserved suppression effects of TRIM5α orthologs from multiple species on both HIV-1 and endo-retroelement HERV-K LTR activities have also been demonstrated. These findings provide new insights into the molecular mechanisms by which proviral latency is initially established and activatable proviruses are resilenced by histone deacetylase recruitment.

Sparse matrix multiplication in a record-low power self-rectifying memristor array for scientific computing.

Memristor-enabled in-memory computing provides an unconventional computing paradigm to surpass the energy efficiency of von Neumann computers. Owing to the limitation of the computing mechanism, while the crossbar structure is desirable for dense computation, the system's energy and area efficiency degrade substantially in performing sparse computation tasks, such as scientific computing. In this work, we report a high-efficiency in-memory sparse computing system based on a self-rectifying memristor array. This system originates from an analog computing mechanism that is motivated by the device's self-rectifying nature, which can achieve an overall performance of ~97 to ~11 TOPS/W for 2- to 8-bit sparse computation when processing practical scientific computing tasks. Compared to previous in-memory computing system, this work provides over 85 times improvement in energy efficiency with an approximately 340 times reduction in hardware overhead. This work can pave the road toward a highly efficient in-memory computing platform for high-performance computing.

TRIM28 negatively regulates the RLR signaling pathway by targeting MAVS for degradation via K48-linked polyubiquitination.

Mitochondrial antiviral signaling (MAVS) protein is a core signaling adapter in the retinoid acid-inducible gene-I-like receptor (RLR) signaling pathway that recruits downstream signaling factors, ultimately leading to the activation of type Ⅰ interferons. However, the mechanisms that modulate the RLR signaling pathway by manipulating MAVS are not fully understood. Previous studies suggested that tripartite motif 28 (TRIM28) participates in regulating innate immune signaling pathways by inhibiting the expression of immune-related genes at the transcriptional level. In this study, we characterized TRIM28 as a negative regulator of the RLR signaling pathway in a MAVS-dependent manner. Overexpression of TRIM28 inhibited the MAVS-induced production of type Ⅰ interferons and proinflammatory cytokines, while knocking down TRIM28 exerted the opposite effect. Mechanistically, TRIM28 targeted MAVS for proteasome-mediated degradation via K48-linked polyubiquitination. The RING domain of TRIM28, especially the cysteine residues at positions 65 and 68, was critical for the suppressive effect of TRIM28 on MAVS-mediated RLR signaling, while each of the C-terminal domains of TRIM28 contributed to its interaction with MAVS. Further investigation revealed that TRIM28 transferred ubiquitin chains to the K7, K10, K371, K420, and K500 residues of MAVS. Together, our results reveal a previously uncharacterized mechanism involving TRIM28 in fine-tuning innate immune responses and provide new insights into the mechanisms by which MAVS is regulated, which contribute to the understanding of the molecular mechanisms underlying immune homeostasis maintenance.

[Temporal and Spatial Variation Characteristics of Heavy Metal in Atmospheric Deposition in China from 2000 to 2018].

Owing to the significant impact of heavy metals in atmospheric deposition on soil, clear knowledge on the present situation and temporal and spatial variation in fluxes of heavy metals in atmospheric deposition all around China is urgently needed. In this study, we collected 99 published papers on deposition fluxes of heavy metals from 2001 to 2021 based on the CNKI and Web of Science database and extracted 718 to 1672 monitoring points from these papers. The Meta-analysis method was used to calculate the weighted average of deposition fluxes of heavy metals, and the spatial-temporal characteristics in different periods from 2000 to 2018 were studied by subgroup analysis, which compared the differences between different types of areas, such as agricultural and rural areas and urban and industrial areas. The results showed that the annual fluxes of heavy metals in atmospheric deposition[mg·(m2·a)-1] in China were as follows:Zn (96.75)>Pb (23.37)>Cu (12.77)>Cr (11.04)>Ni (6.61)>As (2.97)>Cd (0.48)>Hg (0.05). Overall, the estimated value of deposition fluxes in China from 2000 to 2018 was higher than that of rural areas in England from 1995 to 1998. The deposition fluxes in industrial areas and urban areas were much higher than those in the agricultural and rural areas, especially the industrial areas where the heavy metal pollution was more serious. The deposition fluxes of As and Cd in the Changsha-Zhuzhou-Xiangtan area were relatively high, whereas the atmospheric deposition of heavy metals in Northeast China, the Pearl River Delta, and North China Plain was more serious than that in the other areas. In the past 20 years, the annual deposition fluxes of Cd fluctuated around the overall average, without an obviously declining trend, whereas the deposition fluxes of Cd in the urban, agricultural, and rural areas showed a trend of growth. These results suggested that precise and risk control measures of atmospheric emissions should be established based on the characteristics of regional industrial structure, which should cover all levels, all types, and all regions. In addition, more restrictive measures should be taken to solve the current problem caused by the higher deposition flux of Cd in atmospheric deposition.

Papain-like protease of SARS-CoV-2 inhibits RLR signaling in a deubiquitination-dependent and deubiquitination-independent manner.

The newly emerged severe acute respiratory syndrome (SARS) coronavirus-2 (SARS-CoV-2) can result in dysregulated interferon (IFN) responses that contribute to disease severity. The papain-like protease of SARS-CoV-2 (SCoV2-PLpro) has been previously reported to attenuate IFN responses, but the underlying mechanism is not fully understood. In this study, we found that SCoV2-PLpro potently suppressed IFN production and signaling induced by Sendai virus as well as RIG-I-like receptor (RLR) signaling pathway components, including RIG-I, MAVS, TBK1, TRAF3, TRAF6, and IRF3. SCoV2-PLpro exhibited different specificity and efficiency than SARS-CoV PLpro, with the former exerting a greater inhibitory effect on the RIG-I- and TRAF3-mediated IFN response but a weaker effect on the MAVS-mediated IFN response. Furthermore, we showed that SCoV2-PLpro significantly reduced K63-ubiquitination of RIG-I, MAVS, TBK1, TRAF3, TRAF6, and IRF3 and K48-ubiquitination of IκBα, which are known critical for the innate immune signal transduction. The deubiquitinating (DUB) activity of SCoV2-PLpro required a catalytic residue cysteine 111 (C111) but not the UBL domain. Notably, by utilizing the DUB-defective C111 mutant, we demonstrated that SCoV2-PLpro targeted RLR signaling pathway regulators via deubiquitination-dependent and -independent mechanisms, with the inhibitory activities of RIG-I and TBK1 correlating with DUB function, whereas the antagonism effects on MAVS, TRAF3, TRAF6, and IRF3 independent on DUB activity. Overall, our results reveal that SCoV2-PLpro evolves differential IFN antagonism activity from SCoV1-PLpro and it targets multiple key RLR signaling pathway components via various mechanisms, providing insights into SARS-CoV-2 pathogenesis and clues for developing antiviral therapies for COVID-19.

[Effect of Xijiao Dihuang Combined Prescription on Human Dendritic Cell Function Induced by Lipopolysaccharide].

OBJECTIVE: To observe the effects of drug-containing serum of Xijiao Dihuang combined prescription(XJDH) on the related functions of dendritic cells(DCs) induced in vitro, and to explore the mechanisms underlying the effectiveness of XJDH treatment on primary immune thrombocytopenia(ITP). METHODS: Peripheral blood samples were colle-ted from 6 healthy volunteers. Mononuclear cells were isolated by density gradient centrifugation, and CD14+ mononuclear cells were collected by the magnetic separation technique. CD14+ mononuclear cells were induced into immature DCs by recombinant human granulocyte-macrophage colony stimulating factor (GM-CSF) and recombinant human interleukin 4 (IL-4). Immature DCs were divided into three groups: control group, model group and XJDH group. CCK-8 assay was used to determine the intervention concentration and time of drug-containing serum. Lipopolysaccharide(LPS) with the final concentration of 1 µg/ml was added to model group and XJDH group respectively for 24 h to induce DCs maturation. Normal rat serum was added to control group and model group, and XJDH was added to XJDH group for 24 h. Flow cytometry was used to detect the levels of CD80, CD83 and HLA-DR on the surface of DCs. Western blot was used to detect the expression of TLR4 and NF-κB, and levels of IL-6, IL-12 and TNF-α in cell supernatant was detected by ELISA. RESULTS: Compared with the control group, LPS stimulation increased the expression of CD80, CD83 and HLA-DR, with subsequent increasing expression of TLR4 and NF-κB, as well as IL-6, IL-12 and TNF-α increased(P<0.05). In comparison with model group, the expression of DCs surface molecules CD80, CD83 and HLA-DR, DCs' expression of TLR4 and NF-κB protein, and the levels of IL-6, IL-12 and TNF-α in the cell supernatant of XJDH group decreased after the intervention of XJDH (P<0.05). CONCLUSION: Drug containing serum of Xijiao Dihuang combined prescription can down-regulate TLR4/NF-κB signaling pathway related protein expression, inhibit DCs maturation, and reduce proinflammatory factor secretion, which may be one of the mechanisms of drug-containing serum of Xijiao Dihuang combined prescription in the treatment of immune thrombocytopenia.

[Combined Effect of Weathered Coal Based Amendments and Soil Water Management on Methylmercury Accumulation in Paddy Soil and Rice Grains].

A pot experiment and field experiment were designed to study the changes in the grain methyl mercury content in paddy soil and rice yield by sowing soil amendments that contained weathered coal, CaCO3, and Na2SeO3 as the main raw materials, combined with water management in a paddy field (80% field capacity after the heading and flowering periods). The results showed that:① In pot experiment, the content of methylmercury in rice rhizosphere soil decreased by 86.6% and the content of methylmercury in the rice grains decreased by 65.2% compared with that of the control. In field experiment, the content of methylmercury in rice rhizosphere soil decreased by 77.4% and the content of methylmercury in rice grains decreased by 60.6% upon adding the amendment+water management compared with that of CK. ② The soil pH increased by more than 0.3 in the pot experiment and 0.2 in the field experiment compared with that of the control. Furthermore, rice yield and plant biomass did not decrease in the two parts of the experiment. It can be inferred that the soil amendment and agronomic regulation measures (water management) used in this study have the advantages of quick effects, convenient use, and remarkable control effects and without secondary pollution. More, they can effectively reduce the risk of rice methylmercury exposure.

Effects of TACE and preventive antiviral therapy on HBV reactivation and subsequent hepatitis in hepatocellular carcinoma: a meta-analysis.

BACKGROUND AND AIM: The impact of transarterial chemoembolization (TACE) and preventive antiviral therapy on the occurrence of hepatitis B virus (HBV) reactivation and subsequent hepatitis remains controversial. This meta-analysis aimed to evaluate the effect of TACE and preventive antiviral therapy on the risk of HBV reactivation and subsequent hepatitis. Meanwhile, we explored the role of HBeAg status in HBV reactivation after TACE. METHODS: We performed this meta-analysis with 11 included studies to assess the effect of TACE and preventive antiviral therapy on predicting clinical outcomes in HBV-related hepatocellular carcinoma (HCC). The pooled odds ratios (OR) were calculated using a random or fixed effects model. PUBMED, MEDLINE, EMBASE and the Cochrane Central Register of Controlled were searched for the included articles (from 2000 to December 2017). RESULTS: Our results showed that TACE significantly increased the risk of HBV reactivation (OR: 3.70; 95% CI 1.45-9.42; P < 0.01) and subsequent hepatitis (OR: 4.30; 95% CI 2.28-8.13; P < 0.01) in HCC patients. There was no significant difference in HBV reactivation after TACE between HBeAg positive and negative patients (OR: 1.28; 95% CI 0.31-5.34; P = 0.73). Preventive antiviral therapy could statistically reduce the rate of HBV reactivation (OR: 0.08; 95% CI 0.02-0.32; P < 0.01) and hepatitis (OR: 0.22; 95% CI 0.06-0.80; P = 0.02) in those with TACE treatment. CONCLUSIONS: The present study suggested that TACE was associated with a higher possibility of HBV reactivation and subsequent hepatitis. Preventive antiviral therapy is significantly in favor of a protective effect.

Correlation between S100A11 and the TGF-ß1/SMAD4 pathway and its effects on the proliferation and apoptosis of pancreatic cancer cell line PANC-1.

S100A11 as a S100 protein family member has been documented to play dual-direction regulation over cancer cell proliferation. We explored the role of S100A11 in the proliferation and apoptosis of pancreatic cancer cell line PANC-1 and the potential mechanisms involving the TGF-ß1/SMAD4/p21 pathway. S100A11 and TGF-ß1 protein expressions in 30 paraffin-embedded specimens were evaluated by immunohistochemistry. S100A11 and TGF-ß1 expression in PANC-1 cell line was suppressed using small interfering RNA (siRNA), respectively. Subsequently, pancreatic cancer cell apoptosis was measured by Cell Counting Kit-8 and flow cytometry, and S100A11 and TGF-ß1/SMAD4/p21 pathway proteins and genes were detected with Western blotting and quantitative polymerase chain reaction (qPCR). S100A11 cytoplasmic/nuclear protein translocation was examined using NE-PER® cytoplasm/nuclear protein extraction in cells interfered with TGF-ß1 siRNA. Our results showed that S100A11 expression was positively correlated with TGF-ß1 expression in pancreatic cancerous tissue. Silencing TGF-ß1 down-regulated intracellular P21WAF1 expression by 90%, blocked S100A11 from cytoplasm entering nucleus, and enhanced cell proliferation. Silencing S100A11 down-regulated intracellular P21 expression and promoted cell apoptosis without significantly changing TGF-ß1 and SMAD4 expression. Our findings revealed that S100A11 and TGF-ß1/SMAD4 signaling pathway were related but mutually independent in regulating PANC-1 cells proliferation and apoptosis. Other independent mechanisms might be involved in S100A11's regulation of pancreatic cell growth. S100A11 could be a potential gene therapy target for pancreatic cancer.

Actin related protein 3 (ARP3) promotes apoptosis of intestinal epithelial cells in ulcerative colitis.

Apoptosis in intestinal epithelial cells (IECs) promotes the development of ulcerative colitis (UC), a type of inflammatory bowel disease (IBD). Efficient clearance of apoptotic cells is essential for tissue homeostasis in metazoans. Actin related protein 3 (ARP3) promotes endothelial dysfunction. The expression and function of ARP3 in UC remains unclear. In this study, the expression of apoptotic markers as p53, Bax, Cleaved-Caspease9 and Cleaved-Caspease3 were proved to be increased in the intestinal epithelial cells (IECs) of UC patients and in a mouse disuccinimidyl suberate(DSS)-induced colitis model; meanwhile, ARP3 expression was elevated. ARP3 expression levels and the severity of symptoms in patients with UC were positively correlated. By knocking down ARP3 in a TNF-α-treated NCM-460 cell colitis model, the apoptotic markers described above were all decreased. In conclusion, our data indicates that ARP3 might promote the apoptosis of IECs in UC, revealing a potential molecular target for treating UC.

Characterization and proteomic profiling of pancreatic cancer-derived serum exosomes.

Pancreatic cancer (PC) is one of the most lethal cancers known worldwide, and its prognosis is poor in most patients. Exosomes are nanosized extracellular vesicles, which are released from various cell types. They are involved in cellular communication. The diagnosis and treatment of PC were improved substantially with exosomes. In this study, we isolated PC-derived exosomes and investigated their proteomic profile. Then, we conducted bioinformatic analysis on proteomic data. Differential ultracentrifugation was performed to isolate exosomes from human serum samples and four PC cell lines. Transmission electron microscopy and Western blot analysis were used to characterize the isolated exosomes. Liquid chromatography coupled with tandem mass spectrometry was conducted to identify the proteome of serum exosomes. Proteomic analysis demonstrated that all the serum exosomes were derived from three cohorts of human subjects; these serum exosomes contained a total of 655 proteins, out of which 315 proteins overlapped with ExoCarta database. Gene oncology and kyoto encyclopedia of genes and genomes analyses provided the functional annotation of the proteome. Interestingly, 18 or 14 proteins were upregulated and 11 or 14 proteins were downregulated in serum exosomes derived from patients with PC as compared with in serum exosomes derived from healthy volunteers or from pancreatitis patients respectively. Annexin A11, a calcium-dependent phospholipid-binding protein, was expressed in a PC cell line (CFPAC-1)-derived exosomes and in tumor tissues of patients with PC, respectively. Our data provided a basic foundation for further studies on the protein composition of PC-derived exosomes and its involvement in PC biology.

ß2-AR regulates the expression of AKR1B1 in human pancreatic cancer cells and promotes their proliferation via the ERK1/2 pathway.

Psychological stress has been recognized as a well-documented risk factor associated with ß2-adrenergic receptor (ß2-AR) in the development of pancreatic cancer. Aldo-keto reductase 1 member B1 (AKR1B1) is a potential interacting partner of ß2-AR, but the effect of their interaction on pancreatic cancer cells is not known at present. We found a positive correlation between AKR1B1 and ß2-AR expression in pancreatic cancer tissue samples, and co-localization of these proteins in the human pancreatic cancer BXPC-3 cell line. Compared to the controls, the CFPAC-1 and PANC-1 pancreatic cancer cells overexpressing ß2-AR and AKR1B1 respectively showed significantly higher proliferation rates, which is attributed to higher proportion of cells in the S phase and decreased percentage of early apoptotic cells. Furthermore, overexpression of ß2-AR led to a significant increase in the expression of AKR1B1 and phosphorylated extracellular signal-regulated kinase (p-ERK1/2). Overexpression of AKR1B1 significantly decreased ß2-AR levels and increased that of p-ERK1/2. Taken together, ß2-AR directly interacted with and up-regulated AKR1B1 in pancreatic cancer cells, and promoted their proliferation and inhibited apoptosis via the ERK1/2 pathway. Our findings also highlight the ß2-AR-AKR1B1 axis as a potential therapeutic target for pancreatic cancer.

A Comparison of Traditional and Novel Methods for the Separation of Exosomes from Human Samples.

Exosomes are discrete populations of small (40-200 nm in diameter) membranous vesicles that are released into the extracellular space by most cell types, eventually accumulating in the circulation. As molecular messengers, exosomes exert a broad array of vital physiologic functions by transporting information between different cell types. Because of these functional properties, they may have potential as biomarker sources for prognostic and diagnostic disease. Recent research has found that exosomes have potential to be utilized as drug delivery agents for therapeutic targets. However, basic researches on exosomes and researches on their therapeutic potential both require the existence of effective and rapid methods for their separation from human samples. In the current absence of a standardized method, there are several methods available for the separation of exosomes, but very few studies have previously compared the efficiency and suitability of these different methods. This review summarized and compared the available traditional and novel methods for the extraction of exosomes from human samples and considered their advantages and disadvantages for use in clinical laboratories and point-of-care settings.

Sex comb on midleg like-2 is a novel specific marker for the diagnosis of gastroenteropancreatic neuroendocrine tumors.

Sex comb on midleg like-2 (SCML2) is a polycomb-group protein that encodes transcriptional repressors essential for appropriate development in the fly and in mammals. On the basis of previous findings, the present study aimed to explore the possibility of developing SCML2 into a new diagnostic marker for gastroenteropancreatic neuroendocrine tumors (GEP-NETs). A total of 64 paired GEP-NET tissues and adjacent non-tumorous tissues were obtained from patients who had undergone surgical resection between January 2009 and January 2014, and the expression of SCML2 and two neuroendocrine markers, namely synaptophysin (Syn) and chromogranin A (CgA), in the tissues was assessed by immunohistochemistry. Strong SCML2 staining was observed predominantly in the cell nuclei of GEP-NET tissues, and the overall expression rate and staining intensity of SCML2 were higher than those of Syn or CgA, respectively. Spearman rank correlation analysis demonstrated that SCML2 was not correlated with either Syn or CgA, while the combined detection of SCML2 with Syn or with CgA increased the diagnostic sensitivity to 100%. SCML2 expression in GEP-NETs was associated with several clinicopathological parameters, such as histological type, tumor grade, depth of invasion and clinical stage. Kaplan-Meier survival curves revealed that patients with higher SCML2 expression had lower survival rates than those with lower expression levels, while Cox proportional hazards regression analysis revealed that SCML2 was not an independent prognostic factor for GEP-NET patients. Therefore, SCML2 may have potential as a specific marker for joint use with other markers to improve the diagnostic efficiency of GEP-NETs.

Far upstream element-binding protein 1 (FUBP1) is a potential c-Myc regulator in esophageal squamous cell carcinoma (ESCC) and its expression promotes ESCC progression.

The human far upstream element (FUSE) binding protein 1 (FUBP1) belongs to an ancient family which is required for proper regulation of the c-Myc proto-oncogene. Although c-Myc plays an important role in development of various carcinomas, the relevance of FUBP1 and their contribution to esophageal squamous cell carcinoma (ESCC) development remain unclear. In this study, we aimed to investigate the relationship between FUBP1 and c-Myc as well as their contribution to ESCC development. Western blot and immunohistochemical analyses were performed to evaluate FUBP1 expression. Coimmunoprecipitation analysis was performed to explore the correlation between FUBP1 and c-Myc in ESCC. In addition, the role of FUBP1 in ESCC proliferation was studied in ESCC cells through knocking FUBP1 down. The regulation of FUBP1 on proliferation was confirmed by Cell Counting Kit-8 (CCK-8) assay, flow cytometric assays, and clone formation assays. The expressions of FUBP1 and c-Myc were both upregulated in ESCC tissues. In addition to correlation between expression of FUBP1 and tumor grade, we also confirmed the correlation of FUBP1, c-Myc, and Ki-67 expression by twos. Moreover, upregulation of FUBP1 and c-Myc in ESCC was associated with poor survival. FUBP1 was confirmed to activate c-Myc in ESCC tissues and cells. FUBP1 was demonstrated to promote proliferation of ESCC cells. Moreover, downregulation of both FUBP1 and c-Myc was confirmed to inhibit proliferation of ESCC cells. Our results indicated that FUBP1 may potentially stimulate c-Myc expression in ESCC and its expression may promote ESCC progression.

[Determination of Total Selenium and Arsenic in Coal by Wet Digestion Hydride Generation Atomic Fluorescence Spectrometry (HG-AFS)].

In the present work we presented a new method for determination of total Se and As in coal by electric hot plate-mixed acids-hydride generation atomic fluorescence spectrometry (HG-AFS), the wet digestion method. The detailed operation procedures of the new method are as follows: About 0. 05~0. 10 g of powdered (200 mesh) coal sample was placed in a glass beaker, 10 mL of nitric acid (HNO3) and 2 mL of perchloric acid (HClO4) were added to the beaker in sequence, then the beaker was covered with a watching glass and placed in a fume cupboard standing overnight. The beaker was placed on an electric hot plate (180 °C) for sample decomposition the next day. The beaker was moved away from the electric hot plate when white smoke arose in the beaker, the sample color turned white or grey and the solution turned clear. Three milliliter of hydrochloric acid (HCl) solution (6 mol . L-1) was added to the beaker after the temperature of the beaker returned to room temperature. The beaker was heated on the electric hot plate again, and then moved away when white smoke started arising again. One milliliter of HCI was added in the beaker after the temperature of the beaker returned to room temperature. After that, the digested sample was transferred to a 25 mL test tube which was filled with ultrapure water to the tube's full volume. This solution was used for Se determination directly. Three milliliter of the Se test solution prepared above was transferred to a 15 mL glass test tube, 1 mL of thiourea/ascorbic acid solution (2. 5 g . mL-1) and 1 mL of the concentrated HCl was added to the 15 mL test tube. The test tube was then filled with ultrapure water to its full volume. The solution was used for As determination after shaking well and 40 min standing. Finally, Se and As concentrations in these prepared solutions were measured by using the AFS-9780 instrument (Beijing Haiguang Instrument Co. , LTD, Beijing, China). Two Chinese Coal Certified Reference Materials (GBW11115 and GBW11117) were tested using this method, and the recoveries of As were 99. 7%~100. 3% and the relative standard deviation (RSD) for As and Se were 5. 6%~6. 0% and 11. 1%~13. 5%, respectively. The limits of detection (LOD) of the method for Se and As determination were 0. 01 and 0. 05 µg . L-1, respectively. These results indicated that this new method was suitable for Se and As determination in coal, and it had the advantages of simple operation, high accuracy and reproducibility compared with the Chinese National Standard method.

Transplantation of mouse embryonic stem cell-derived oligodendrocytes in the murine model of globoid cell leukodystrophy.

INTRODUCTION: Globoid cell leukodystrophy (GLD) is a severe disorder of the central and peripheral nervous system caused by the absence of galactocerebrosidase (GALC) activity. Cell-based therapies are highly promising strategies for GLD. In this study, G-Olig2 mouse embryonic stem cells (ESCs) were induced into oligodendrocyte progenitor cells (OPCs) and were implanted into the brains of twitcher mice, an animal model of GLD, to explore the therapeutic potential of the cells. METHODS: The G-Olig2 ESCs were induced into OPCs by using cytokines and a multi-step differentiation procedure. Oligodendrocyte markers were detected by reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry. The toxicity of psychosine to OPCs was determined by a cell proliferation assay kit. The GALC level of OPCs was also examined. OPCs were labeled with Dir and transplanted into the brains of twitcher mice. The transplanted cells were detected by in-Vivo Multispectral Imaging System and real-time PCR. The physiological effects of twitcher mice were assessed. RESULTS: Oligodendrocyte markers were expressed in OPCs, and 76%±5.76% of the OPCs were enhanced green fluorescent protein (eGFP)-positive, eGFP was driven by the Olig2 promoter. The effect of psychosine on cell viability indicated that OPCs were more resistant to psychosine toxicity. The GALC level of OPCs was 10.0±1.23 nmol/hour per mg protein, which was significantly higher than other cells. Dir-labeled OPCs were injected into the forebrain of post-natal day 10 twitcher mice. The transplanted OPCs were myelin basic protein (MBP)-positive and remained along the injection tract as observed by fluorescent microscopy. The level of the Dir fluorescent signal and eGFP mRNA significantly decreased at days 10 and 20 after injection, as indicated by in-Vivo Multispectral Imaging System and real-time PCR. Because of poor cell survival and limited migration ability, there was no significant improvement in brain GALC activity, MBP level, life span, body weight, and behavioral deficits of twitcher mice. CONCLUSIONS: ESC-derived OPC transplantation was not sufficient to reverse the clinical course of GLD in twitcher mice.

High expression of peroxiredoxin 4 affects the survival time of colorectal cancer patients, but is not an independent unfavorable prognostic factor.

Peroxiredoxin 4 (Prx4) has a number of important biological functions, such as efficient antioxidant capacity and promotion of cell proliferation and differentiation. The purpose of this study was to investigate the expression and significance of Prx4 in human colorectal cancer (CRC). Quantitative polymerase chain reaction (qPCR) was performed to detect Prx4 in 8 freshly frozen specimens of CRC and their adjacent normal tissues. In addition, immunohistochemical analysis was performed to detect Prx4 in 59 specimens of CRC and 26 of adjacent normal tissues. The immunohistochemical and qPCR results demonstrated that the expressions of the Prx4 gene and protein were higher in CRC compared to those in the adjacent normal tissues. The expression intensity of the Prx4 protein was correlated with depth of invasion (P=0.001), lymph node metastasis (P=0.006) and Dukes' classification (P=0.004) in CRC. The Kaplan-Meier survival curves revealed that high Prx4 expression was correlated with short survival time. However, the Cox proportional hazards regression analysis did not identify Prx4 as an independent prognostic marker for CRC (P>0.05). These results suggested that Prx4 may be associated with carcinogenesis and the development of CRC and it may be a prognostic marker for postoperative CRC patients.

S100 family signaling network and related proteins in pancreatic cancer (Review).

The occurrence and development of pancreatic cancer is a complex process convoluted by multi-pathogenies, multi-stages and multi-factors. S100 proteins are members of the S100 family that regulate multiple cellular pathways related to pancreatic cancer progression and metastasis. S100 proteins have a broad range of intracellular and extracellular functions, including the regulation of protein phosphorylation and enzyme activity, calcium homeostasis and the regulation of cytoskeletal components and transcriptional factors. S100 proteins interact with receptor for advanced glycation end-products (RAGE), p53 and p21, which play a role in the degradation of the extracellular matrix (ECM) and metastasis, and also interact with cytoskeletal proteins and the plasma membrane in pancreatic cancer progression and metastasis. S100A11 and S100P are significant tumor markers for pancreatic cancer and unfavorable predictors for the prognosis of patients who have undergone surgical resection. Recently, S100A2 has been suggested to be a negative prognostic biomarker in pancreatic cancer, and the expression of S100A6 may be an independent prognostic impact factor. The expression of S100A4 and S100P is associated with drug resistance, differentiation, metastasis and clinical outcome. This review summarizes the role and significance of the S100 family signaling network and related proteins in pancreatic cancer.

Effect of combined mutations in the enhancer II and basal core promoter of hepatitis B virus on development of hepatocellular carcinoma in Qidong, China.

AIM: To investigate the roles of mutations in enhancer II (Enh II), basal core promoter (BCP) and precore (PC) regions of hepatitis B virus (HBV) in the progression of hepatocellular carcinoma (HCC) in Qidong, China. METHODS: We conducted a case-control study within a cohort of 2387 male HBV carriers who were recruited between August and September 1996. The HBV DNA sequence was determined in 152 HCC and 131 chronic hepatitis patients. Mutation exchanges during follow up in 115 cases were compared with 108 controls with serum samples taken during a similar length of follow up. In addition, a longitudinal study was conducted in 22 cases in which serial serum samples were available before HCC. RESULTS: After adjustment for age, history of cigarette smoking and alcohol consumption, hepatitis B e-antigen positivity, T1653, V1753 and T1762/A1764 double mutations were associated with risk of HCC. Multivariate analysis showed that T1653, V1753 and T1762/A1764 double mutations were independent risk factors of HCC. Moreover, a significant biological gradient of HCC risk by number of mutations in Enh II/BCP regions was observed. Paired samples analysis indicated that the increased HCC risk for at-risk sequence mutations were attributable to the persistence of these mutations, but not a single time point mutation. The longitudinal observation demonstrated a gradual combination of mutations in Enh II/BCP regions accumulated during the development of HCC. CONCLUSION: T1653, V1753 and T1762/A1764 double mutations were independent risk factors of HCC. The effect of combined mutations in Enh II/BCP regions increased the risk and persistence of at-risk sequence mutations and was critical for HCC development.