[Effect of ultrasound contrast agent targeting gelatin on uptake of mouse ascites hepatocellular carcinoma cell lines with high lymphatic metastasis].

Objective: To analyze the effect of ultrasound contrast agent targeting gelatin on uptake of high lymphatic metastasis cell lines of mouse hepatocellular carcinoma with peritoneal effusion. Methods: The modified double emulsifying solvent evaporation method was used to construct the macromolecule contrast agent PLGA-Cooh. The carbodiimide was used to connect the monoclonal antibody of gelatin with the contrast agent PLGA-Cooh, and the targeted ultrasound contrast agent Gsn-PLGA was established. The particle size and Zeta potential of the targeted ultrasound contrast agent were measured by laser particle size analyzer. The surface binding of the contrast agent to the gelatin monoclonal antibody was evaluated by immunofluorescence. Hca-F cells with high lymphatic metastasis were cultured in mice with peritoneal effusion hepatocellular carcinoma. Target-seeking ability in vitro was evaluated by in vitro uptake test, and the imaging effect of the contrast agent in vitro was evaluated by in vitro developing test. Results: The contrast agent is white powder with good water solubility. The average particle size and surface potential were (569.68±6.96) nm and (-10.95±2.43) mV, respectively. The fluorescent antibody binding rate of non-targeted and targeted ultrasound contrast agent labeled with DiI were 0.84% and 95.89%, respectively. The results showed that the targeted ultrasound contrast agent Gsn-PLGA had a better of developing effect in vitro. Hca-F cells with high expression of gelsolin protein had stronger uptake ability of targeted ultrasound contrast agent and stronger green fluorescence in vitro than those with low expression of gelsolin protein (P<0.05). Moreover, targeted ultrasound contrast agent Gsn-PLGA had stronger targeting to the gelsolin protein. The echo of the targeted ultrasound contrast agent Gsn-PLGA was uniform and fine, without attenuating echo of the back. Simultaneously, the development effect was more obvious with the increase of contrast agent concentration (P<0.05). Conclusion: Ultrasound contrast agent Gsn-PLGA targeting gelatin can bind Hca-F cells with high expression of gelatin and display a good imaging effect in vitro.

Serial T-SPOT.TB in household contacts of tuberculosis patients: a 6-year observational study in China.

BACKGROUND: Screening tuberculosis (TB) contacts is a priority for TB control; however, it remains inadequate in most regions of China.OBJECTIVE: To investigate the progression of latent TB infection (LTBI) using the interferon-gamma release assay (IGRA) in contacts of active TB patients.DESIGN: This longitudinal prospective observational study included 159 household contacts aged ≥14 years without preventive treatment who were followed up for 6 years to compare their conversion and reversion rates using the T-SPOT®.TB IGRA to diagnose LTBI.RESULTS: Among the 159 household contacts, LTBI positivity was 47.5%. Age was independently associated with LTBI (OR 3.6, 95%CI 1.81-7.14; P = 0.00). T-SPOT.TB conversion rates were respectively 29.4% and 18.8% at 3- and 6-year follow-up. The reversion rates were 9.4% of contacts during the 3-year follow-up period, which increased to 38.2% at the 6-year follow-up. A decreasing trend in spot-forming cells on T-SPOT.TB was observed in most patients at the 6-year follow-up.CONCLUSION: LTBI prevalence among household contacts was relatively high, particularly in elderly patients. Furthermore, serial IGRA testing was highly dynamic; however, this overall trend gradually decreased over time, even if preventive therapy was not prescribed.

miRNA-185 regulates retained fetal membranes of cattle by targeting STIM1.

Retained fetal membranes (RFM) of cows is an important reproductive disturbance, and is related to miRNA-185. Stromal interaction molecule 1 (STIM1), a potential target gene of miRNA-185, could influence placenta release via regulating Ca2+ concentration intracellular. The aim of this study was to explore the mechanism of RFM by investigating the regulatory relationship between miRNA-185 and STIM1 in primary uterine caruncel epithelial (UCE) cells. Serum samples of healthy Holstein dairy cows (n = 20) and RFM cows (n = 12), with a similar age, parity, weight, and milk yield, were collected to detect Ca2+ concentration at prepartum 1-5 d and postpartum 6, 12 and 24 h. Caruncle tissues were collected from healthy (n = 6) and RFM cows (n = 6) at 12 h after calving. Quantitative polymerase chain reaction (Q-PCR) and western blotting (WB) were performed to detect the mRNA and protein levels of STIM1, respectively. UCE cells were cultured by the explant culture method, further purified, and subsequently treated with PmirGLO-STIM1-Mut + miRNA-185 mimics and mirGLO-STIM1-Mut + miRNA-185 NC. Q-PCR and WB were performed to detect mRNA and protein levels of STIM1 with treated miRNA-185 mimics. Serum levels of Ca2+ from RFM cows were abnormally decreased at prepartum 1 d and postpartum 6, 12 and 24 h. Expression level of STIM1 was down-regulated in the caruncle tissue of RFM cows. The luciferase activity was decresed about 30.9% by miRNA-185 mimics (p < 0.01), and the mRNA and protein levels of STIM1 were downregulated miRNA-185-mimics. It was suggesting that miRNA-185 might play an important role in RFM through regulating the expression of STIM1.

Three-dimensional model and molecular mechanism of Mycobacterium tuberculosis catalase-peroxidase (KatG) and isoniazid-resistant KatG mutants.

Mycobacterium tuberculosis KatG enzyme functions both as catalase for removing hydrogen peroxide (H(2)O(2)) and as peroxidase for oxidating isoniazid (INH) to active form of anti-tuberculosis drug. Although mutations in M. tuberculosis KatG confer INH resistance in tuberculous patients, structural bases for INH-resistant mutations in the KatG gene remains poorly understood. Here, three M. tuberculosis KatG mutants bearing Arg418--> Gln, Ser315 --> Thr, or Trp321 --> Gly replacement were assessed for changes in catalase-peroxidase activities and possible structure bases relevant to such changes. These three M. tuberculosis KatG mutants exhibited a marked impairment or loss of catalase-peroxidase activities. The possible structural bases for the mutant-induced loss of enzyme activities were then analyzed using a three-dimensional model of M. tuberculosis KatG protein constructed on the basis of the crystal structure of the catalase-peroxidase from Burkholderia pseudomallei. The model suggests that three M. tuberculosis KatG mutants bearing Arg418 --> Gln, Ser315 -->Thr, or Trp321--> Gly replacement affect enzyme activities by different mechanisms, although each of them impacts consequently on a heme-associated structure, the putative oxidative site. Moreover, in addition to the widely accepted substrate-binding site, M. tuberculosis KatG may bear another H(2)O(2) binding site. This H(2)O(2) binding site appears to interact with the catalytic site by a possible electron-transfer chain, a Met255-Tyr229-Trp107 triad conserved in many catalase-peroxidases. The Ser315 --> Thr mutant may have direct effect on the catalytic site by interfering with electron transfer in addition to the previously proposed mechanism of steric constraint.