Risk stratification for sudden cardiac death

Recent advances in pharmacological and device-based therapies have provided a range of management options for patients at risk of sudden cardiac death (SCD). Since all such interventions come with their attendant risks, however, stratification procedures aimed at identifying those who stand to benefit overall have gained a new degree of importance. This review assesses the value of risk stratification measures currently available in clinical practice, as well as of others that may soon enter the market. Parameters that may be obtained only by performing invasive cardiac catheterisation procedures are considered separately from those that may be derived using more readily available non-invasive techniques. It is concluded that effective stratification is likely to require the use of composite parameters and that invasive procedures might only be justified in specific sub-groups of patients.     

Isolation of transcription factors binding auxin response elements using a yeast one-hybrid system

Plant hormones play an important role during higher plant embryogenesis. Auxin is central to the development of vascular tissues, formation of lateral and adventitious roots, control of apical dominance, and tropic responses. Auxin response element (AuxRE), present in the promoters of many auxin-induced genes, can confer auxin responsiveness. Using carrot somatic embryo under specific developmental phase, a cDNA expression library was constructed. Several plasmids were recombined containing the tetramer of AuxRE as a bait. After screening by a yeast one-hybrid system, one positive clone was confirmed and characterized. Electrophoretic mobility shift assay showed that AxRF1 protein expressed in yeast cell could bind AuxRE in vitro. It suggests that AxRF1 participates in regulation of the expression of auxin responsive gene during carrot somatic embryogenesis.     

Efficient synthesis of 'redox-switched' naphthoquinone thiol-crown ethers and their biological activity evaluation

Series of naphthoquinone thiol-crown ethers had been prepared. The antibacterial, antifungal, and cytotoxic activities of these synthetic naphthoquinone thiol-crown ethers were investigated. All of the compounds tested displayed antibacterial, cytotoxic and antifungal activities. The bis-naphthoquinone thiol-crown ether 7a was the most potent inhibitor among tested analogues against Staphylococcus aureus methicillin resistance with MIC value of 2.68 microM.     

Lithocholic acid decreases expression of bile salt export pump through farnesoid X receptor antagonist activity

Bile salt export pump (BSEP) is a major bile acid transporter in the liver. Mutations in BSEP result in progressive intrahepatic cholestasis, a severe liver disease that impairs bile flow and causes irreversible liver damage. BSEP is a target for inhibition and down-regulation by drugs and abnormal bile salt metabolites, and such inhibition and down-regulation may result in bile acid retention and intrahepatic cholestasis. In this study, we quantitatively analyzed the regulation of BSEP expression by FXR ligands in primary human hepatocytes and HepG2 cells. We demonstrate that BSEP expression is dramatically regulated by ligands of the nuclear receptor farnesoid X receptor (FXR). Both the endogenous FXR agonist chenodeoxycholate (CDCA) and synthetic FXR ligand GW4064 effectively increased BSEP mRNA in both cell types. This up-regulation was readily detectable at as early as 3 h, and the ligand potency for BSEP regulation correlates with the intrinsic activity on FXR. These results suggest BSEP as a direct target of FXR and support the recent report that the BSEP promoter is transactivated by FXR. In contrast to CDCA and GW4064, lithocholate (LCA), a hydrophobic bile acid and a potent inducer of cholestasis, strongly decreased BSEP expression. Previous studies did not identify LCA as an FXR antagonist ligand in cells, but we show here that LCA is an FXR antagonist with partial agonist activity in cells. In an in vitro co-activator association assay, LCA decreased CDCA- and GW4064-induced FXR activation with an IC(50) of 1 microm. In HepG2 cells, LCA also effectively antagonized GW4064-enhanced FXR transactivation. These data suggest that the toxic and cholestatic effect of LCA in animals may result from its down-regulation of BSEP through FXR. Taken together, these observations indicate that FXR plays an important role in BSEP gene expression and that FXR ligands may be potential therapeutic drugs for intrahepatic cholestasis.     

Two novel antifungal peptides distinct with a five-disulfide motif from the bark of Eucommia ulmoides Oliv

Two antifungal peptides, named EAFP1 and EAFP2, have been purified from the bark of Eucommia ulmoides Oliv. Each of the sequences consists of 41 residues with a N-terminal blockage by pyroglutamic acid determined by automated Edman degradation in combination with the tandem mass spectroscopy and the C-terminal ladder sequencing analysis. The primary structurs all contain 10 cysteines, which are cross-linked to form five disulfide bridges with a pairing pattern (C1-C5, C2-C9, C3-C6, C4-C7, C8-C10). This is the first finding of a plant antifungal peptide with a five-disulfide motif. EAFP1 and EAFP2 show characteristics of hevein domain and exhibit chitin-binding properties similar to the previously identified hevein-like peptides. They exhibit relatively broad spectra of antifungal activities against eight pathogenic fungi from cotton, wheat, potato, tomato and tobacco. The inhibition activity of EAFP1 and EAFP2 can be effective on both chitin-containing and chitin-free fungi. The values of IC(50) range from 35 to 155 microg/ml for EAFP1 and 18 to 109 microg/ml for EAFP2. Their antifungal effects are strongly antagonized by calcium ions.     

天津汉沽农田土壤－植物系统中汞的分布、迁移和积累

本文研究了受汞污染的农田土壤—植物系统中汞的分布,迁移和积累的规律。土壤中的汞在离污染源3公里的范围内含量最高;主要集中在0一20厘米的土壤上层,几乎不往下迁移。植物可以从土壤和大气中吸收、积累汞。在汉沽区没有发现由于汞污染所造成的植物受害症状。植物中的汞含量与土壤中的汞含量成正相关。土壤汞含量与水稻茎叶汞含量的相关系数为0.836(N=7),与糙米汞含量的相关系数为0.898(N=7)。植物不同部位的汞含量根>叶>茎>种子。不同作物种子比较,糙米>高粱>小麦。在大气中汞含量高的地段,植物地上部分汞含量高于根。土壤、植物中的汞不断地向大气扩散,而大气中的汞随着降雨、降尘等又不断地沉降到土壤和植物的气生表面,并可被植物吸收。汞向其邻近地区扩散的能力较小。     

Amino acid substitution in the lactose carrier protein with the use of amber suppressors.

Five lacY mutants with amber stop codons at known positions were each placed into 12 different suppressor strains. The 60 amino acid substitutions obtained in this manner were tested for growth on lactose-minimal medium plates and for transport of lactose, melibiose, and thiomethylgalactoside. Most of the amino acid substitutions in the regions of the putative loops (between transmembrane alpha helices) resulted in a reasonable growth rate on lactose with moderate-to-good transport activity. In one strain (glycine substituted for Trp-10), abnormal sugar recognition was found. The substitution of proline for Trp-33 (in the region of the first alpha helix) showed no activity, while four additional substitutions (lysine, leucine, cysteine, and glutamic acid) showed low activity. Altered sugar specificity was observed when Trp-33 was replaced by serine, glutamine, tyrosine, alanine, histidine, or phenylalanine. It is concluded that Trp-33 may be involved directly or indirectly in sugar recognition.     

Community and Proteomic Analysis of Methanogenic Consortia Degrading Terephthalate

Degradation of terephthalate (TA) through microbial syntrophy under moderately thermophilic (46 to 50°C) methanogenic conditions was characterized by using a metagenomic approach (A. Lykidis et al., ISME J. 5:122–130, 2011). To further study the activities of key microorganisms responsible for the TA degradation, community analysis and shotgun proteomics were used. The results of hierarchical oligonucleotide primer extension analysis of PCR-amplified 16S rRNA genes indicated that Pelotomaculum, Methanosaeta, and Methanolinea were predominant in the TA-degrading biofilms. Metaproteomic analysis identified a total of 482 proteins and revealed a distinctive distribution pattern of microbial functions expressed in situ. The results confirmed that TA was degraded by Pelotomaculum spp. via the proposed decarboxylation and benzoyl-coenzyme A-dependent pathway. The intermediate by-products, including acetate, H₂/CO₂, and butyrate, were produced to support the growth of methanogens, as well as other microbial populations that could further degrade butyrate. Proteins related to energy production and conservation, and signal transduction mechanisms (that is, chemotaxis, PAS/GGDEF regulators, and stress proteins) were highly expressed, and these mechanisms were important for growth in energy-limited syntrophic ecosystems.     

2-Methoxyestradiol Induces Mitotic Arrest,Apoptosis, and Synergistic Cytotoxicity with Arsenic Trioxide in Human Urothelial Carcinoma Cells

2-Methoxyestradiol (2-ME), an endogenous derivative of 17β-estradiol, has been reported to elicit antiproliferative responses in various tumors. In this study, we investigated the effects of 2-ME on cell viability, proliferation, cell cycle, and apoptosis in human urothelial carcinoma (UC) cell lines. We used two high-grade human bladder UC cell lines (NTUB1 and T24). After treatment with 2-ME, the cell viability and apoptosis were measured by MTT assay and flow cytometry (fluorescence-activated cell sorting), with annexin V-FITC staining and propidium iodide (PI) labeling. DNA fragmentation was analyzed by agarose gel electrophoresis. Flow cytometry with PI labeling was used for the cell cycle analyses. The protein levels of caspase activations, poly (ADP-ribose) polymerase (PARP) cleavage, phospho-histone H2A.X, phospho-Bad, and cell cycle regulatory molecules were measured by Western blot. The effects of the drug combinations were analyzed using the computer software, CalcuSyn. We demonstrated that 2-ME effectively induces dose-dependent cytotoxicity and apoptosis in human UC cells after 24 h exposure. DNA fragmentation, PARP cleavage, and caspase-3, 7, 8, 9 activations can be observed with 2-ME-induced apoptosis. The decreased phospho-Bad (Ser136 and Ser155) and mitotic arrest of the cell cycle in the process of apoptosis after 2-ME treatment was remarkable. In response to mitotic arrest, the mitotic forms of cdc25C, phospho-cdc2, cyclin B1, and phospho-histone H3 (Ser10) were activated. In combination with arsenic trioxide (As₂O₃), 2-ME elicited synergistic cytotoxicity (combination index <1) in UC cells. We concluded that 2-ME significantly induces apoptosis through decreased phospho-Bad and arrests bladder UC cells at the mitotic phase. The synergistic antitumor effect with As₂O₃ provides a novel implication in clinical treatment of UC.