Simultaneous determination of biotoxins DSP and AZAs in bivalve molluscs and fish by liquid chromatography/tandem mass spectrometry.

RATIONALE: A method has been developed for simultaneous determination of the toxins OA, DTX-1, AZA-1, AZA-2 and AZA-3 in various aquatic products as these can cause diarrhoetic shellfish poisoning (DSP) in humans, an intoxication characterized by vomiting and diarrhea. METHODS: Separation of the toxins was achieved on a C18 column (150 mm × 2.1 mm, 3.5 µm) using an acetonitrile/water gradient with formic acid as an eluent modifier. Electrospray ionisation (ESI) in negative mode was used to generate the molecule related ion [M-H](-), for OA and DTX-1, while ESI in positive mode was used to generate the molecule related ion [M+H](+) for AZAs. Samples were extracted with 80% methanol, followed by partitioning with ethyl acetate, purified on a Poly-Sery MAX cartridge and finally analyzed by LC/ESI-MS/MS in the multiple reaction monitoring (MRM) mode. RESULTS: The limit of detection (LOD) and limit of qualification (LOQ) of the method were in the range of 0.02-0.79 µg/kg and 0.07-2.64 µg/kg in Scomberomorus niphonius, blood clam and oyster, respectively, recoveries of the toxins at three fortification levels ranged from 71.3% to 104.8% with relative standard deviation from 1.0% to 12.5%. The calibration curves were well linear between the LC peak area of the selected ion pair and the concentration of the toxins, with the correlation coefficient over 0.99. CONCLUSIONS: The method was sufficiently sensitive to permit the determination of the toxins DSP and AZA in sea food.

Proteomic research of high-glucose-activated endothelial microparticles and related proteins to Alzheimer's disease.

The study was designed to discover the biological function of endotheliocyte-derived microparticles in diabetes condition. A quantitative shotgun proteomics methodology was performed to study the proteome of these high-glucose-activated endothelial microparticles. A total of 1428 proteins were identified, containing 1421 and 1423 proteins in control and high-glucose groups, respectively. According to the ExoCarta database, 669 proteins have previously been identified in microparticles. The proteins associated with disease were identified in this study, and notably, 30 proteins have been reported to be associated with Alzheimer's disease, including amyloid beta A4 protein. Besides, the peptide abundance of amyloid beta A4 protein from control group was much less than that from high-glucose group. In conclusion, this work revealed the proteome of endothelial microparticles in mimic diabetes condition and provided a new proteomic evidence for Alzheimer's disease to be counted as the type 3 diabetes.

GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis in rats.

Hydrogen sulfide (H2S) is a gasotransmitter that regulates cardiovascular functions. The present study aimed to determine the protective effect of slow-releasing H2S donor GYY4137 on myocardial ischemia and reperfusion (I/R) injury and to investigate the possible signaling mechanisms involved. Male Sprague-Dawley rats were treated with GYY4137 at 12.5 mg/(kg·day), 25 mg/(kg·day) or 50 mg/(kg·day) intraperitoneally for 7 days. Then, rats were subjected to 30 minutes of left anterior descending coronary artery occlusion followed by reperfusion for 24 hours. We found that GYY4137 increased the cardiac ejection fraction and fractional shortening, reduced the ischemia area, alleviated histological injury and decreased plasma creatine kinase after myocardial I/R. Both H2S concentration in plasma and cystathionine-γ-lyase (CSE) activity in the myocardium were enhanced in the GYY4137 treated groups. GYY4137 also decreased malondialdehyde and myeloperoxidase levels in serum, attenuated superoxide anion level and suppressed phosphorylation of mitogen activated protein kinases in the myocardium after I/R. Meanwhile, GYY4137 increased the expression of Bcl-2 but decreased the expression of Bax, caspase-3 activity and apoptosis in the myocardium. The data suggest that GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis.

Platelet-derived microparticles are implicated in remote ischemia conditioning in a rat model of cerebral infarction.

AIM: Remote ischemic preconditioning protects against ischemic organ damage by giving short periods of subcritical ischemia to a remote organ. We tested the hypothesis that remote ischemic conditioning can attenuate cerebral stroke in a rat middle cerebral artery occlusion (MCAO) model by microparticles (MPs). METHODS AND RESULTS: MPs were extracted from healthy rats that underwent hindlimb ischemia-reperfusion preconditioning (RIPC), and were transfused into rats that had undergone MCAO without RIPC. The transfusion resulted in an increase in platelet-derived MPs in blood and reduction in infarction area, confirmed by both 2-3-5-triphenyltetrazolium chloride staining and magnetic resonance imaging, albeit to a lesser degree than RIPC itself. Behavioral tests (modified Neurological Severity Score [mNSS]) were calculated to judge the behavioral change. However, no significant difference was observed after MP transfusion in 24 h or the following consecutive 9 days. CONCLUSIONS: RIPC induces an increase in MPs, and platelet-derived MPs may confer at least part of the remote protective effect against cerebral ischemic-reperfusion injury.

Celastrol prevents atherosclerosis via inhibiting LOX-1 and oxidative stress.

Celastrol is a triterpenoid compound extracted from the Chinese herb Tripterygium wilfordii Hook F. Previous research has revealed its anti-oxidant, anti-inflammatory, anti-cancer and immunosuppressive properties. Here, we investigated whether celastrol inhibits oxidized low-density lipoprotein (oxLDL) induced oxidative stress in RAW 264.7 cells. In addition, the effect of celastrol on atherosclerosis in vivo was assessed in apolipoprotein E knockout (apoE(-/-)) mouse fed a high-fat/high-cholesterol diet (HFC). We found that celastrol significantly attenuated oxLDL-induced excessive expression of lectin-like oxidized low density lipoprotein receptor-1(LOX-1) and generation of reactive oxygen species (ROS) in cultured RAW264.7 macrophages. Celastrol also decreased IκB phosphorylation and degradation and reduced production of inducible nitric oxide synthase (iNOS), nitric oxide (NO) and proinflammatory cytokines such as tumor necrosis factor (TNF)-α and IL-6. Celastrol reduced atherosclerotic plaque size in apoE(-/-) mice. The expression of LOX-1 within the atherosclerotic lesions and generation of superoxide in mouse aorta were also significantly reduced by celastrol while the lipid profile was not improved. In conclusion, our results show that celastrol inhibits atherosclerotic plaque developing in apoE(-/-) mice via inhibiting LOX-1 and oxidative stress.