The Study of Overexpression of Peroxiredoxin-2 Reduces MPP+-Induced Toxicity in the Cell Model of Parkinson's Disease.

Parkinson's disease (PD) is a chronic neurodegenerative disorder characterized by dopaminergic neuron loss, which is related to excessive reactive oxygen species (ROS) accumulation. Endogenous peroxiredoxin-2 (Prdx-2) has potent anti-oxidative and anti-apoptotic effects. Proteomics studies revealed plasma levels of Prdx-2 were significantly lower in PD patients than in healthy individuals. For further study of the activation of Prdx-2 and its role in vitro, SH-SY5Y cells and the neurotoxin 1-methyl-4-phenylpyridinium (MPP+) were used to model PD. ROS content, mitochondrial membrane potential, and cell viability were used to assess the effect of MPP+ in SH-SY5Y cells. JC-1 staining was used to determine mitochondrial membrane potential. ROS content was detected using a DCFH-DA kit. Cell viability was measured using the Cell Counting Kit-8 assay. Western blot detected the protein levels of tyrosine hydroxylase (TH), Prdx-2, silent information regulator of transcription 1 (SIRT1), Bax, and Bcl-2. The results showed that MPP+-induced accumulation of ROS, depolarization of mitochondrial membrane potential, and reduction of cell viability occurred in SH-SY5Y cells. In addition, the levels of TH, Prdx-2, and SIRT1 decreased, while the ratios of Bax and Bcl-2 increased. Then, Prdx-2 overexpression in SH-SY5Y cells showed significant protection against MPP+ -induced neuronal toxicity, as evidenced by the decrease in ROS content, increase in cell viability, increase in the level of TH, and decrease in the ratios of Bax and Bcl-2. Meanwhile, SIRT1 levels increase with the level of Prdx-2. This suggests that the protection of Prdx-2 may be related to SIRT1. In conclusion, this study indicated that overexpression of Prdx-2 reduces MPP+-induced toxicity in SH-SY5Y cells and may be mediated by SIRT1.

[Analytical methods for urinary biomarkers of human exposure to phthalates].

Phthalates (PAEs) are a class of endocrine-disrupting chemicals. In recent years, the harmful effects of PAEs on human health, in particular their toxicity toward the reproductive system and development, have received significant attention because of their increasing production and usage. PAEs are ubiquitous in the environment and food products, resulting in unavoidable and long-term exposure in humans. Therefore, exposure and risk assessments of PAEs in humans are necessary. Screening and quantification of phthalate metabolites in urine is an important method for evaluating PAEs exposure, and establishing accurate analytical methods for this purpose has become a high priority. Phthalate monoesters and secondary metabolites are the most commonly targeted biomarkers of exposure to short-and long-chain PAEs, respectively. The combination of off-line or on-line solid phase extraction (SPE) with high performance liquid chromatography-tandem mass spectrometry has become the preferred method for the determination of phthalate metabolites. This paper reviews the analytical methods available for the detection of urinary phthalate metabolites and discusses the advantages, limitations, and challenges presented by each method in practical applications.

Dummy molecularly imprinted solid phase extraction of climbazole from environmental water samples.

Dummy molecularly imprinted polymer (DMIP) for climbazole (CBZ) was synthesized for the first time employing miconazole (MNZ) as the dummy template together with methacrylic acid (MAA) monomer, ethylene glycol dimethacrylate (EGDMA) cross-linker and acetonitrile (ACN) porogen. The selectivity and capacity of the prepared MNZ-DMIP was estimated for CBZ by high-performance liquid chromatography (HPLC) and equilibrium binding experiments. Imprinting factor (IF) with a value of 7.0 was achieved, much higher than the CBZ templated MIP (IF = 3.5). Heterogeneous binding sites were found in the MNZ-DMIP, the corresponding saturation capacity and dissociation constant for the high and low affinity binding sites were 6.761 µmol g-1 and 0.3027 mmol L-1, 43.60 µmol g-1 and 4.055 mmol L-1, respectively. High efficient method based on dummy molecularly imprinted solid phase extraction (DMISPE) coupled with HPLC was established for the selective enrichment of CBZ in river and tap water using MNZ-DMIP as sorbent. DMISPE conditions including sample loading pH/volume, selective washing and elution solvents were carefully optimized. The developed method showed good recoveries (82.3-96.2%) and repeatability (RSDs 0.6-4.9%, n = 5) for samples spiked at three different concentration levels (0.2, 1.0 and 5.0 µg L-1). The detection limit was determined as 0.012 µg L-1. The results demonstrated good potential of this method for sample pretreatment of CBZ in environmental water samples.

Controlled Manipulation of Metal-Organic Framework Layers to Nanometer Precision Inside Large Mesochannels of Ordered Mesoporous Silica for Enhanced Removal of Bisphenol A from Water.

Considerable attention has been paid on the design of hierarchical porous metal-organic framework (MOF) composites, which not only enhances the performance but also broadens the applications of MOFs. So far, controlled manipulation of nanometer-thick MOF layers in ordered mesochannels, while retaining their respective intrinsic properties, is still a main challenge because of the difficulty of growing MOFs in confined space. Herein, using a step-by-step coordination method, the formation of a hierarchical micro-mesoporous hybrid with a wall (channel wall and coating layer) thickness of up to 8.0 nm and open pore size down to 7.7 nm has been achieved based on large mesoporous SBA-15, and the wall thickness with nanometer precision can be controlled by adjusting the growth cycles of zeolite imidazolate framework-8 (ZIF-8) coating layers. Compared to pure ZIF-8, the obtained ZIF-8@SBA-15 composites showed more than 2-fold enhancement in adsorption capacity and approximately 20-fold improvement in the adsorption rate constant for bisphenol A in water, which could be ascribed to the synergistic effects of the high adsorption ability from ZIF-8 and the fast diffusion property from SBA-15. More importantly, the degraded ZIF-8@SBA-15 composite can be completely restored by a simple immersion into 2-methylimidazole solution. The easy restorability and good reusability further enable ZIF-8@SBA-15 as a promising adsorbent for effectively removing organic contaminants from water.

Hyperbranched mixed-mode anion-exchange polymeric sorbent for highly selective extraction of nine acidic non-steroidal anti-inflammatory drugs from human urine.

This paper describes the poly(divinylbenzene) (PDVB) supported synthesis of quaternized hyperbranched macromolecules (QHMs) and its use as a highly selective, high-capacity mixed-mode anion-exchange (MAX) sorbent. In detail, the aminated PDVB support was firstly synthesized by copolymerization of divinylbenzene and 2-(diethylamino)ethyl methacrylate via Pickering emulsion polymerization. The QHMs were then grafted on PDVB by a divergent synthesis involving consecutive reactions of resorcinol diglycidyl ether with methylamine (N, N-dimethylethanolamine for terminal epoxides), which brought in a high density of quaternary ammonium functionalities. The changes of specific surface area (SBET), pore volume and ion exchange capacity (IEC) with generation number reveal that the QHMs have been grown successfully within the large meso-channels of the porous aminated PDVB. The best compromise between the SBET, pore volume and IEC was obtained at the 4th generation (G4). Due to the highest IEC (0.47 meq/g), the G4-QHMs was successfully applied for mixed-mode solid phase extraction (SPE) of acidic non-steroidal anti-inflammatory drugs (NSAIDs). An efficient approach based on the mixed-mode SPE coupled with HPLC-UV was developed for highly selective extraction and cleanup of nine NSAIDs (tolmetin, TLM; ketoprofen, KEP; naproxen, NAP; flurbiprofen, FLB; diclofenac, DIC; indomethacin, INM; ibuprofen, IBP; mefenamic acid, MFA; tolfenamic acid, TFA) in human urine samples. Under the optimized conditions, the method exhibited satisfactory recoveries ranging from 81.9% to 104.0% with relative standard deviation (RSD) values below 8.5%, good sensitivity (0.004-0.009 µg mL-1 limit of detection) and good linearity (coefficient of determination, R2 > 0.997, 0.01-0.2 µg mL-1 for NAP, 0.05-1.0 µg mL-1 for FLB, DIC, INM, MFA, TFA, 0.1-2.0 µg mL-1 for TLM, KEP, IBP). The hyperbranched MAX sorbent is superior to Oasis HLB and comparable to Oasis MAX in obtaining clean chromatographic profiles. Our results demonstrate the potential application of the hyperbranched MAX for complex sample analysis.

Determination of nine bisphenols in sewage and sludge using dummy molecularly imprinted solid-phase extraction coupled with liquid chromatography tandem mass spectrometry.

This paper describes the determination of bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF), bisphenol E (BPE), bisphenol B (BPB), bisphenol AF (BPAF), bisphenol AP (BPAP), bisphenol Z (BPZ) and tetrabromobisphenol A (TBBPA) in sewage and sludge samples. A highly class-selective dummy molecularly imprinted polymer was used for solid phase extraction (SPE) and clean-up of the samples. Bisphenols was quantified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The developed method had acceptable recoveries (43.6-101%), precision (RSDs: 1.5-15%) and matrix effects (-6.7 to 28%). The method limits of quantitation (MLOQs) for nine bisphenols in sewage and sludge samples were 0.0007-16.3 ng L-1 and 0.0004-8.28 ng g-1 dry weight (dw), respectively. The method was applied to a survey of a municipal wastewater treatment plant (WWTP) in Dalian. All of the tested bisphenols, except BPB and BPZ, were presented in the analyzed samples. BPA, BPS, and BPF with the concentrations 412, 109 and 66.4 ng L-1 in the WWTP influent, respectively, were the predominant bisphenols. The results demonstrated that BPS and BPF have become the most frequently used substitutes of BPA.

Multifunctionalized mesoporous silica as an efficient reversed-phase/anion exchange mixed-mode sorbent for solid-phase extraction of four acidic nonsteroidal anti-inflammatory drugs in environmental water samples.

A mesoporous silica Santa Barbara Amorphous-15 (SBA-15) has been first functionalized with 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (a silane with three amines) and then reacted with an excess of phenyl glycidyl ether to generate a mixed-mode anion-exchanger containing both anion-exchange (three amines) and reversed-phase (multiple ether-linked phenyls) functionalities in a single branched ligand. The resulting material has been characterized by scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption measurements, Fourier-transform infrared spectroscopy, and elemental analysis. The results obtained indicated a BET specific surface area (SBET) of 362.5m2g-1, a pore volume of 0.70cm3g-1 with a narrow pore size distribution centered at 6.6nm, and carbon and nitrogen contents of 28.30% and 2.84%, respectively. The dimensions of these particles (∼5µm diameter, ∼60µm length), their large surface areas, their high-density functionalities and anion-exchange mixed-mode characteristics make them very attractive for highly effective solid phase extraction (SPE) of acidic nonsteroidal anti-inflammatory drugs (NSAIDs). The important parameters on extraction efficiency including sample pH, breakthrough volume, type and volume of eluent were optimized. A simple and sensitive analytical method based on mixed-mode SPE coupled to high-performance liquid chromatography with ultraviolet detection (HPLC-UV) was developed and successfully applied to the analysis of four NSAIDs (ketoprofen, naproxen, diclofenac, and ibuprofen) in spiked real water samples with satisfactory recoveries (80.6-110.9%) and repeatability (relative standard deviation <11.3%, n=3). The limit of detections of four NSAIDs were 0.006-0.070µgL-1 for tap water, and 0.014-0.16µgL-1 for river water and wastewater, with the enrichment factors of 806-1109-fold.

Preparation of a reversed-phase/anion-exchange mixed-mode spherical sorbent by Pickering emulsion polymerization for highly selective solid-phase extraction of acidic pharmaceuticals from wastewater.

The present work represents a simple and effective preparation of a novel mixed-mode anion-exchange (MAX) sorbent based on porous poly[2-(diethylamino)ethyl methacrylate-divinylbenzene] (poly(DEAEMA-DVB)) spherical particles synthesized by one-step Pickering emulsion polymerization. The poly(DEAEMA-DVB) particles were quaternized with 1,4-butanediol diglycidyl ether (BDDE) followed by triethylamine (TEA) via epoxy-amine reaction to offer strong anion exchange properties. The synthesized MAX sorbent was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, nitrogen adsorption-desorption measurements and elemental analysis. The MAX sorbent possessed regular spherical shape and narrow diameter distribution (15-35µm), a high IEC of 0.54meq/g, with carbon and nitrogen contents of 80.3% and 1.62%, respectively. Compared to poly(DEAEMA-DVB), the MAX sorbent exhibited decreased SBET (390.5 vs. 515.3m2g-1), pore volume (0.74 vs. 0.85cm3g-1) and pore size (16.8 vs. 17.3nm). Moreover, changes of N content for producing the MAX sorbent reveal a successful two-step quaternization, which can be highly related to such a high IEC. Finally, the MAX sorbent was successfully evaluated for selective isolation and purification of some selected acidic pharmaceuticals (ketoprofen, KEP; naproxen, NAP; and ibuprofen, IBP) from neutral (hydrocortisone, HYC), basic (carbamazepine, CAZ; amitriptyline, AMT) pharmaceuticals and other interferences in water samples using solid phase extraction (SPE). An efficient analytical method based on the MAX-based mixed-mode SPE coupled with HPLC-UV was developed for highly selective extraction and cleanup of acidic KEP, NAP and IBP in spiked wastewater samples. The developed method exhibited good sensitivity (0.009-0.085µgL-1 limit of detection), satisfactory recoveries (82.1%-105.5%) and repeatabilities (relative standard deviation < 7.9%, n=3).

Solid-phase extraction based on a molecularly imprinted polymer for the selective determination of four benzophenones in tap and river water.

This work reports the preparation of molecularly imprinted polymer particles for the selective extraction and determination of four benzophenones from aqueous media. The polymer was prepared by using 4-vinylpridine as functional monomer, ethylene glycol dimethacrylate as cross-linker, acetonitrile as porogenic solvent and 2,2',4,4'-tetrehydroxybenzophenone as template. Good specific adsorption capacity (Qmax = 27.90 µmol/g) for 2,2',4,4'-tetrehydroxybenzophenone was obtained in the sorption experiment and good class selectivity for 2,2',4,4'-tetrehydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dehydroxy-4,4'-dimethoxybenzophenone was demonstrated by the chromatographic evaluation experiment. Factors affecting the extraction efficiency of the molecularly imprinted solid-phase extraction procedure were investigated systematically. An accurate and sensitive analytical method based on the molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography and diode array detection has been successfully developed for the simultaneous determination of four benzophenones from tap water and river water with method detection limits of 0.25-0.72 ng/mL. The recoveries of benzophenones for water samples at two spiking levels (500 and 5000 ng/mL for each benzophenone) were in the range of 86.9-103.3% with relative standard deviations (n = 3) below 9.2%.

[The comparison of three operation methods for treatment of femoral intertrochanteric fracture].

OBJECTIVE: To investigate the therapeutic effect on femoral intertrochanteric fracture for three kinds of treatment methods and make theoretical analysis to offer basis on choosing the proper treatment method in clinic. METHODS: We retrospectively reviewed the clinical and radiological records of 198 patients with femoral intertrochanteric fracture for three kinds of different treatment: unilateral external fixation apparatus (51 cases), dynamic hip screw (57 cases), internal fixation of Gamma nail (90 cases) from January 2001 to October 2006. The union of fracture and weight loading time, the averages length of stay,the incidence of complications,the functional evaluation of hip joint (the rate of excellent and good results) were compared and the curative effects were analyzed in different methods. RESULTS: All the patients were followed-up for 36 months in average (from 8 months to 51 months). The union of fracture time were no statistically significant among the three groups (P>0.05). The weight loading time and incidence of complications were statistical significance among the three groups (P<0.05). Among the three groups,the incision length, operation time,blood loss and drainage in dynamic hip screw group were more than other groups, the unilateral external fixation apparatus group were less, Gamma nail group were in moderate. According to the Sanders' hip functional standard score,there were significant difference between the Gamma nail group and the other two groups (compared with dynamic hip screw group, P<0.05; compared with unilateral external fixation apparatus group, P<0.01). CONCLUSION: The internal fixation of Gamma nail is a good choice for treating femoral intertrochanteric fracture. The weight loading time is earlier,the recovery of hip joint function is better,the incidence of complications is less in Gamma nail group than other two groups.