Rational design of a functionalized metal-organic framework for ratiometric fluorimetric sensing of Hg2+ in environmental water.

A target-responsive ratiometric fluorimetric sensing strategy for Hg2+ has been rationally designed. The sensing probe was established based on a functionalized metal-organic framework, which was prepared with 3,5-dicarboxyphenylboronic acid (DCPB) as the functional ligand and Eu3+ as the metal junction. The porous nano-spheres of Eu-MOF with an arylboronic acid as the functional recognition group for Hg2+ exhibited tunable optical properties with dual emission fluorescence signals at 338 nm and 615 nm. In the presence of Hg2+, arylmercury was formed by a specific transmetalation reaction between Hg2+ and arylboronic acid groups, which blocks the energy transfer between the ligand and Eu3+. Thereby, the fluorescence signal of Eu-MOF/BA at 615 nm decreased, while the fluorescence signal at 338 nm remained almost constant. The ratiometric fluorimetric sensing for Hg2+ was achieved by calculating the peak intensity ratio of F615/F338 based on the reference signal at 338 nm and the response signal at 615 nm. The detection limit of Hg2+ was as low as 0.0890 nM, and the recovery rate of the actual environmental water sample ranged from 90.92% to 118.50%. Therefore, the excellent performance of the ratiometric fluorimetric sensing method for Hg2+ makes it attractive for the detection of heavy metal ions in environmental monitoring.

Zeolitic imidazolate framework-8 for ratiometric fluorescence sensing tetracyclines in environmental water based on AIE effects.

A ratiometric fluorimetric sensing strategy with Zeolitic imidazolate framework-8 (ZIF-8) has been developed for the analysis of tetracycline (TC) in environmental water samples. ZIF-8 with polyhedral structure was synthesized at room temperature exhibiting blue fluorescence at 445 nm. Especially, the as-prepared ZIF-8 could conduct the aggregation-induced emission (AIE) effect in the presence of TC through electrostatic, hydrogen bond, π-π stacking, and coordination interactions. As a result, a strong yellow-green fluorescence appeared and a new fluorescence peak at 505 nm was observed, although the initial fluorescence peak at 445 nm of ZIF-8 was almost unchanged. A ZIF-8-based fluorimetric platform was thereby designed for sensing TC by using ZIF-8 as the fluorescent probe with the peak at 445 nm as the reference and the one at 505 nm as the changing signal, which should increase with the increasing concentrations of TC. Moreover, the quantitative analysis of TC could be carried out through the ratiometric peak intensities of F505/F445, with a detection limit as low as 14.7 nM. Additionally, the ratiometric fluorescent analysis method was successfully employed to detect TC in environmental water samples, indicating that ZIF-8 might be a good luminescent sensor for probing the pollutants in the environmental water.

The effect of carvedilol and propranolol on portal hypertension in patients with cirrhosis: a meta-analysis.

PURPOSE: Several randomized controlled clinical trials have been conducted to investigate the role of carvedilol and propranolol on the effect of portal pressure in patients with cirrhosis, leading to controversial results. Current meta-analysis was performed to compare the efficacy of the two drugs on portal pressure. PATIENTS AND METHODS: Two-hundred and ninety eligible patients were recruited. Published studies were selected based on PubMed, the Cochrane Library, Chinese Journal Full-text Database, and Wanfang Database. The outcome measurements included the mean difference (MD) in the percentage of hepatic vein pressure gradient reduction (%HVPG reduction), the risk ratio (RR) of nonresponders in hemodynamic assessment, and the percentage of mean arterial pressure reduction (%MAP reduction). Subgroup analysis was performed. RESULTS: Seven trials were identified (including five acute and three long-term drug administration randomized controlled trials). A summary of pooled MD between the %HVPG reduction is as follows: overall -8.62 (confidence interval [CI] -11.76, -5.48, P<0.00001), acute -10.05 (CI -14.24, -5.86, P<0.00001), and long term -6.80 (CI -11.53, -2.07, P=0.005), while summary of pooled RR of hemodynamic nonresponders with carvedilol was as follows: overall 0.64 (CI 0.51, 0.81, P=0.0002), acute 0.63 (CI 0.47, 0.85, P=0.002), and long term 0.67 (CI 0.47, 0.97, P=0.03). Both of the outcome measurements favored carvedilol. Significant heterogeneity (P<0.1, I (2)=92%) existed between the two treatment groups in %MAP reduction. No considerable difference could be observed in the %MAP reduction through the poor overlapping CI boundaries. CONCLUSION: Carvedilol has a greater portal hypertensive effect than propranolol. Further comparative trials of the two drugs are required to identify the effect of MAP reduction.

Wnt-induced secreted protein 1/CCN4 in liver fibrosis both in vitro and in vivo.

BACKGROUND: Wnt-induced secreted protein-1 (WISP-1/CCN4) is a member of the CCN family growth factors, and its role in liver fibrosis is largely unknown. METHODS: For in vitro, hepatic stellate cells (HSCs) were isolated from Sprague-Dawley rats. Expression of WISP-1 during progressive activation of cultured rat HSCs was analyzed by qRT-PCR. The effects of TNF-a and TGF-beta1 on WISP-1 expression were analyzed in stellate cell lines HSC-T6 and LX-2. The effect of exogenous WISP-1 protein on LX-2 proliferation was examined. For in vivo, expressions of WISP-1 in fibrotic liver of a carbon tetrachloride (CCl4)-induced fibrosis rat model were analyzed by qRT-PCR and immunohistochemistry. RESULTS: In vitro, WISP-1 was increasingly expressed during progressive activation of cultured rat HSCs. WISP-1 was significantly induced in HSC-T6 cells by TNF-a and in LX-2 cells by TGF-beta1. Recombinant WISP-1 protein promoted LX-2 proliferation in a dose-dependent manner. In vivo, both mRNA and protein expression levels of WISP-1 were increased significantly in experimental hepatic fibrosis model. CONCLUSIONS: Our results showed the upregulation of WISP-1 in both in vitro and in vivo liver fibrosis models, and WISP-1 stimulated the proliferation of HSCs in vitro. These results may be helpful to elucidate the exact role of WISP-1 in liver fibrogenesis.

Noninvasive prediction of large esophageal varices in liver cirrhosis patients.

PURPOSE: Esophageal varices are a dangerous complication of liver cirrhosis. The development of cost effective, noninvasive means for prediction of large esophageal varices could reduce the use of upper gastrointestinal endoscopy in variceal screening and also provide an alternative way to confirm the results of conventional endoscopic diagnosis. Previously proposed predictive models are neither sensitive nor specific. METHODS: A retrospective study based on a group of 104 liver cirrhosis patients was performed. Multiple statistical approaches were used to evaluate the association of large esophageal varices with 20 individual and six compound clinical laboratory variables. A new predictive model was developed. RESULTS: Univariate analysis suggested that eight out of 26 variables were significantly associated with large esophageal varices. Further stepwise logistic regression eventually identified three variables (hemoglobin level, portal vein diameter and the ratio of platelet count/spleen diameter) that contributed significantly to the final regression model. Receiver operating characteristic (ROC) curve analysis showed that this new regression model achieved 77.8% and 72% of diagnostic sensitivity and specificity, respectively, for the prediction of large esophageal varices. In our study group, its diagnostic accuracy (AUROC=0.814) was found to be significantly higher than six predictive models previously published. CONCLUSIONS: No single variable offers self-sufficient predictive function for large esophageal varices. A comprehensive model using multiple variables significantly improves the predictive accuracy in screening the most at risk patients with potential variceal hemorrhage.