Facile synthesis of metal-organic framework-derived SiW12@Co3O4 and its peroxidase-like activity in colorimetric assay.

Over the past few years, artificial enzymes have attracted enormous attention due to their high stabilities and cost-effective productions. In this work, metal-organic framework-derived SiW12@Co3O4 was synthesized in large quantities by stirring the mixture at ambient temperature and calcination. The obtained SiW12@Co3O4 exhibited a highly inherent peroxidase-like activity and excellent stability. Kinetic studies demonstrated that the synthesized SiW12@Co3O4 had a strong binding affinity to 3,3',5,5'-tetramethylbenzidine (TMB), stronger than HRP had. Specifically, the peroxidase-like activity of SiW12@Co3O4 in an aqueous solution was well maintained after incubation at an elevated temperature, at an extreme pH and for a long time. A SiW12@Co3O4-based method was further developed for H2O2 and one-pot glucose detection with good sensitivity and reliability. The facile synthesis approach is expected to facilitate the practical use of metal-organic frameworks and their derivatives as enzyme mimics in the future.

Leverage principle of retardation signal in titration of double protein via chip moving reaction boundary electrophoresis.

In the present work we address a simple, rapid and quantitative analytical method for detection of different proteins present in biological samples. For this, we proposed the model of titration of double protein (TDP) and its relevant leverage theory relied on the retardation signal of chip moving reaction boundary electrophoresis (MRBE). The leverage principle showed that the product of the first protein content and its absolute retardation signal is equal to that of the second protein content and its absolute one. To manifest the model, we achieved theoretical self-evidence for the demonstration of the leverage principle at first. Then relevant experiments were conducted on the TDP-MRBE chip. The results revealed that (i) there was a leverage principle of retardation signal within the TDP of two pure proteins, and (ii) a lever also existed within these two complex protein samples, evidently demonstrating the validity of TDP model and leverage theory in MRBE chip. It was also showed that the proposed technique could provide a rapid and simple quantitative analysis of two protein samples in a mixture. Finally, we successfully applied the developed technique for the quantification of soymilk in adulterated infant formula. The TDP-MRBE opens up a new window for the detection of adulteration ratio of the poor food (milk) in blended high quality one.

Reciprocating free-flow isoelectric focusing device for preparative separation of proteins.

The traditional recycling free-flow isoelectric focusing (RFFIEF) suffered from complex structure, tedious operations and poor extensibility as well as high cost. To address these issues, a novel reciprocating free-flow isoelectric focusing device (ReFFIEF) was developed for proteins or peptides pre-fractionation. In the new device, a reciprocating background flow was for the first time introduced into free flow electrophoresis (FFE) system. The gas cushion injector (GCI) used in the previous continuous free-flow electrophoresis (CFFE) was redesigned for the reciprocating background flow. With the GCI, the reciprocating background flow could be achieved between the GCI, separation chamber and transient self-balance collector (tSBC). In a run, process fluid flowed to and from, forming a stable reciprocating fluid flow in the separation chamber. A pH gradient was created within the separation chamber, and at the same time proteins were focused repeatedly when passing through the chamber under perpendicular electric field. The ReFFIEF procedure was optimized for fractionations of three model proteins, and the optimized method was further used for pre-fractionation of model human serum samples. As compared with the traditional RFFIEF devices developed about 25 years ago, the new ReFFIEF system showed several merits, such as simple design and structure, user-friendly operation and easy to extend as well as low cost.

Association between endothelial nitric oxide synthase polymorphisms and atrial fibrillation: a meta-analysis.

Several recent studies have focused on the association between the promoter polymorphisms 786T/C of the endothelial nitric oxide synthase (eNOS) gene and susceptibility to atrial fibrillation (AF); however, results have been conflicting. We searched Medline, Embase, and the ISI Web of Science through July 1, 2011. Five studies with 1,130 AF cases and 2,340 controls were selected. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated based on fixed- and random-effects models. There was no overall association between eNOS 786T/C and AF risk. In subgroup analysis, stratified by ethnicity, we observed a positive association between the eNOS 786T/C polymorphism and AF risk among Caucasians but not among mixed populations. When stratifying by control source, the overall ORs for population- and hospital-based studies were 1.07 (95% CI, 0.50-2.30) and 0.79 (95% CI, 0.65-0.97) for CC vs. 22T carriers, respectively. In the studies with a sample size greater than 200, the eNOS 786T/C polymorphism decreased AF risk (OR [95% CI]: 0.79 [0.64-0.97] for CC vs. T carriers). This meta-analysis suggests that the 786T/C polymorphism of the eNOS gene is protective against AF risk among Caucasians. Additional large studies based on diverse populations are required to validate this conclusion.

[Association of aldosterone synthase gene -344 T/C polymorphism with early renal damage in Han nationality with essential hypertension].

OBJECTIVE: To investigate whether the -344T/C polymorphism of aldosterone synthase gene is associated with early renal damage in Han nationality with essential hypertension in Shandong province. METHODS: Plasma aldosterone concentration and urinary albumin excretion were measured with radioimmunoassays in 225 patients with essential hypertension, and hypertensives were classified as hypertension with normal albuminuria or hypertension with microalbuminuria according to urinary albumin excretion during 24 hours. -344T/C polymorphism of aldosterone synthase gene was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in controls and hypertensives. RESULTS: No significant differences were found in genotype distribution among groups of control, primary hypertension with normal albuminuria and hypertension with microalbuminuria. The C allele frequency in hypertension with microal buminuria group was significantly higher than that in control and hypertension with normal albuminuria group (P < 0.05). In hypertensive patients, plasma aldosterone concentration and urinary albumin excretion of TC+CC genotypes were significantly higher than that of TT genotype ( P< 0.05). CONCLUSION: These results suggest that -344T/C polymorphism of aldosterone synthase gene may be associated with early renal damage in Han nationality with essential hypertension, C allele may be a genetic factor susceptible to renal damage in hypertensives.

Associations between CYP11B2 gene -344T/C polymorphism and essential hypertension in the Han nationality in Shandong province.

OBJECTIVE: To investigate whether the -344T/C polymorphism of CYP11B2 gene is associated with essential hypertension in the Hans in Shandong province. METHODS: Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured with radioimmunoassays; the hypertensives were classified as low-renin and normal- or high-renin group by PAC/PRA ratio. -344T/C polymorphism was determined by polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) in controls and hypertensives. RESULTS: No significant differences were found in genotype distribution or allele frequency between groups of control and primary hypertension or between groups of control and normal- or high-renin hypertension. The C allele frequency in low-renin hypertension group was significantly higher than that in normotensives and normal- or high-renin hypertension group (P < 0.05). CONCLUSION: These results suggest that -344T/C polymorphism of CYP11B2 gene may be associated with low-renin essential hypertension in the Han nationality in Shandong province.