[Expression and diagnostic value of macrophage inflammatory protein-3α in patients with hepatitis B-related acute-on-chronic liver failure].

Objective: To screen serum protein markers and evaluate their diagnostic application value in hepatitis B-related acute-on-chronic liver failure (HBV-ACLF). Methods: Serum samples of patients with HBV-ACLF, chronic hepatitis B (CHB) and normal healthy volunteers (n = 5/group) were determined by cytokine antibody chip in line with the Chinese Diagnostic Standards Study for HBV-ACLF (COSSH-ACLF) cohort. The differentially expressed proteins significance were identified by microarray analysis and prediction. The preliminary serological markers of HBV-ACLF were screened for diagnosis. The potential markers were determined by enzyme-linked immunosorbent assay (ELISA), area under the receiver operating characteristic curve (AUROC) analysis and liver tissue immunohistochemistry for the diagnosis of HBV-ACLF. Student t-test or Mann-Whitney U test were used to compare the continuous measurement data between the two groups, and analysis of variance and Kruskal-Wallis test were used to compare the continuous measurement data between multiple groups. Results: Cytokine antibody chip preliminary screening results showed that the expression levels of these six cytokines, namely, macrophage inflammatory protein 3α (MIP-3α), hepatocyte growth factor, E-selectin, osteopontin, growth differentiation factor 15 and carcinoembryonic antigen-related cellular adhesion molecule 1 were significantly increased in the HBV-ACLF group. Among them, the expression level of MIP-3α was significantly higher in the HBV-ACLF group (99.6 times higher than CHB group and 146.9 times higher than healthy volunteers' group, respectively, P < 0.0001) as validated by serum ELISA in 132 HBV-ACLF cases, 91 CHB cases and 72 healthy volunteers. AUROC analysis showed that the high expression of MIP-3α could be used as a marker to distinguish patients with HBV-ACLF from CHB. The AUROC was 0.995 (95% CI: 0.990 ~ 1.000), with sensitivity and specificity of 95.5% and. 98.9%, respectively. Immunohistochemistry showed that MIP-3α was positively expressed in HBV-ACLF-derived liver tissues, and negatively expressed in CHB-derived liver and normal liver tissues. Conclusion: Serum MIP-3α level is closely related to the pathological characteristics of HBV-ACLF. Therefore, it may be used as a potential serological marker for the diagnosis of HBV-ACLF.

Rapid and sensitive detection of infectious spleen and kidney necrosis virus by loop-mediated isothermal amplification combined with a lateral flow dipstick.

Loop-mediated isothermal amplification (LAMP) allows rapid amplification of nucleic acids under isothermal conditions. In this report, a 20-min LAMP amplification of the DPOL gene of infectious spleen and kidney necrosis virus (ISKNV) using a biotin-labeled primer was combined with lateral flow dipstick (LFD) chromatography for rapid and simple visual detection of ISKNV-specific amplicons. The LFD process involves a 5-min specific hybridization with an FITC-labeled DNA probe to confirm the presence of complement ISKNV amplicons that were biotinated in LAMP. The resulting DNA duplexes, consisting of labeled probes and amplicons, migrate along the LFD strip by chromatography for 5 min and are trapped at the test line and visualized by biotin labeling. The detection limit of ISKNV by LAMP-LFD was 10 copies. The results show that the LAMP-LFD method has the advantages of better sensitivity and speed and less dependence on equipment than the standard PCR for specifically detecting low levels of ISKNV DNA, and this can be useful in the field as a routine diagnostic tool.

Structure of human thymidylate synthase suggests advantages of chemotherapy with noncompetitive inhibitors.

Thymidylate synthase (TS) is a major target in the chemotherapy of colorectal cancer and some other neoplasms. The emergence of resistance to the treatment is often related to the increased levels of TS in cancer cells, which have been linked to the elimination of TS binding to its own mRNA upon drug binding, a feedback regulatory mechanism, and/or to the increased stability to intracellular degradation of TS.drug complexes (versus unliganded TS). The active site loop of human TS (hTS) has a unique conformation resulted from a rotation by 180 degrees relative to its orientation in bacterial TSs. In this conformation, the enzyme must be inactive, because the catalytic cysteine is no longer positioned in the ligand-binding pocket. The ordered solvent structure obtained from high resolution crystallographic data (2.0 A) suggests that the inactive loop conformation promotes mRNA binding and intracellular degradation of the enzyme. This hypothesis is supported by fluorescence studies, which indicate that in solution both active and inactive forms of hTS are present. The binding of phosphate ion shifts the equilibrium toward the inactive conformation; subsequent dUMP binding reverses the equilibrium toward the active form. Thus, TS inhibition via stabilization of the inactive conformation should lead to less resistance than is observed with presently used drugs, which are analogs of its substrates, dUMP and CH(2)H(4)folate, and bind in the active site, promoting the active conformation. The presence of an extension at the N terminus of native hTS has no significant effect on kinetic properties or crystal structure.