Progresses in GluN2A-containing NMDA Receptors and their Selective Regulators.

NMDA receptors play an important physiological role in regulating synaptic plasticity, learning and memory. GluN2A subunits are the most abundant functional subunits of NMDA receptors expressed in mature brain, and their dysfunction is related to various neurological diseases. According to subunit composition, GluN2A-containing NMDA receptors can be divided into two types: diheteromeric and triheteromeric receptors. In this review, the expression, functional and pharmacological properties of different kinds of GluN2A-containing NMDA receptors as well as selective GluN2A regulators were described to further understand this type of NMDA receptors.

Therapeutic time windows of compounds against NMDA receptors signaling pathways for ischemic stroke.

Much evidence has proved that excitotoxicity induced by excessive release of glutamate contributes largely to damage caused by ischemia. In view of the key role played by NMDA receptors in mediating excitotoxicity, compounds against NMDA receptors signaling pathways have become the most promising type of anti-stroke candidate compounds. However, the limited therapeutic time window for neuroprotection is a key factor preventing NMDA receptor-related compounds from showing efficacy in all clinical trials for ischemic stroke. In this perspective, the determination of therapeutic time windows of these kinds of compounds is useful in ensuring a therapeutic effect and accelerating clinical application. This mini-review discussed the therapeutic time windows of compounds against NMDA receptors signaling pathways, described related influence factors and the status of clinical studies. The purpose of this review is to look for compounds with wide therapeutic time windows and better clinical application prospect.

Analysis of Five Mushroom Toxins in Blood by UPLC-HRMS. / 血液中5ç§è˜‘è‡æ¯’ç´ çš„UPLC-HRMS分析.

OBJECTIVES: To develop a method for the simultaneous and rapid detection of five mushroom toxins (α-amanitin, phallacidin, muscimol, muscarine and psilocin) in blood by ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). METHODS: The blood samples were precipitated with acetonitrile-water solution(Vacetonitril∶Vwater=3∶1) and PAX powder, then separated on ACQUITY Premier C18 column, eluted gradient. Five kinds of mushroom toxins were monitored by FullMS-ddMS2/positive ion scanning mode, and qualitative and quantitative analysis was conducted according to the accurate mass numbers of primary and secondary fragment ions. RESULTS: All the five mushroom toxins had good linearity in their linear range, with a determination coefficient (R2)≥0.99. The detection limit was 0.2-20 ng/mL. The ration limit was 0.5-50 ng/mL. The recoveries of low, medium and high additive levels were 89.6%-101.4%, the relative standard deviation was 1.7%-6.7%, the accuracy was 90.4%-101.3%, the intra-day precision was 0.6%-9.0%, the daytime precision was 1.7%-6.3%, and the matrix effect was 42.2%-129.8%. CONCLUSIONS: The method is simple, rapid, high recovery rate, and could be used for rapid and accurate qualitative screening and quantitative analysis of various mushroom toxins in biological samples at the same time, so as to provide basis for the identification of mushroom poisoning events.

[Research on quality standards of Aleuritopteris Herba].

This study aims to establish quality standards of Aleuritopteris Herba (AH), which could supply scientific evidence for the quality control of AH. The morphological and microscopic identification characters were reformulated. The tests of water content, total ash, acid-insoluble ash and ethanol-soluble extractives of AH were carried out according to the methods recorded in appendix of Chinese Pharmacopeia (2010 edition, volume 1). The TLC method was established by using aleuritopesis A [2,19-diol（2ß,4α）-16-enekaureniod] and reference herb as references. With preparation of aleuritopesis A[2,19-diol（2ß,4α）-16-enekaureniod] reference substance, the content of aleuritopesis A in AH was determined by HPLC. As a result, the macroscopic identification, microscopic features and TLC methods were specific and simple. The water content, total ash, acid-insoluble ash and ethanol-soluble extractive and the content of aleuritopesis A of all samples varied in the ranges of 8.8%-10.9%, 7.6%-11.4%, 2.5%-4.2%, 9.3%-10.2% and 0.56%-0.71%, respectively. The improved quality standard can be used to evaluate and guarantee the quality of AH comprehensively.

[The optical characteristics of hollow cathode discharge striations in nitrogen].

The characteristics of striations in cylindrical hollow cathode discharge were investigated experimentally. The spectra of striations were measured at a pressure of 20 Pa in a discharge of 1.3 mA, in which the main spectra are the emission spectrum lines of the N2 first positive band (B3pi(g)-->A3pi(u)) and second positive band system (C3pi(u)-->B3pi(g)). The spatial characteristics of vibrational temperature of N2 were calculated based on the theory of double molecular spectrum. It is shown that the emission intensity exhibits a periodic structure with an unequal magnitude, and the spectral intensity of bright striation is higher than that of dark striations. The vibrational temperature of bright striation is of the value of 3500-4400K, moreover the vibrational temperature in the bright regions decreases from the cathode to the anode. In addition, the characteristics of striations at 1.0 mA and 1.5 mA were obtained, and the influence of discharge current on the striations was investigated. It is shown that the vibrational temperature and the distance between two striations increase. Finally the reduced electric field was calculated, which is about 44 approximately 49 m(-1) x Pa(-1), moreover it decreases with the increase in discharge current. The results are very useful for understanding the mechanism of discharge striations and for improving the stability of hollow cathode discharge.

Quantification of orelabrutinib in human plasma and cerebrospinal fluid by liquid chromatography tandem mass spectrometry.

A sensitive and simple method was developed to determine orelabrutinib in human plasma and cerebrospinal fluid by liquid chromatography tandem mass spectrometry (LC-MS/MS). The samples were prepared by simple protein precipitation with by 0.1% formic acid acetonitrile solution and efficient separations were performed on the Thermo Hypersll GOLD C18 column (2.1 mm × 150 mm, 5 µm) under a gradient program in a total run time of 9 min. The orelabrutinib was detected by electrospray ionization in positive ion mode with selective reaction monitoring (SRM) and mass spectrometric conditions were optimized in order to increase selectivity and sensitivity. The developed method was validated in terms of its accuracy, precision, selectivity, linearity, recovery, matrix effect, stability, and limits of quantification (LOQ). The lower limit of quantification is 0.50 ng/mL, the intraday and interday precision RSD are both less than 15%, and the recovery rate is 85.7%-92.9%. Finally, the method was successfully applied for the quantitation of orelabrutinib in human plasma and cerebrospinal fluid of clinical patients treated with orelabrutinib.

Methyl 2-[2-(benzyl-oxycarbon-ylamino)-propan-2-yl]-5-hy-droxy-1-methyl-6-oxo-1,6-dihydro-pyrimidine-4-carboxyl-ate.

The title pyrimidine derivative, C(18)H(21)N(3)O(6), was obtained by the reaction of methyl 2-[2-(benzyl-oxycarbon-yl)amino-propan-2-yl]-5-hy-droxy-6-oxo-1,6-dihydro-pyrimidine-4-carboxyl-ate with dimethyl sulfate in dimethyl sulfoxide. The mol-ecule has a V-shaped structure, the phenyl and the pyrimidine rings making a dihedral angle of 43.1 (1)°. The methyl group substituting the pyrimidine ring deviates slightly from the ring mean-plane [C-N-C-C torsion angle = 5.49 (15)°], and the methyl ester substituent has a conformation suitable for the formation of an intra-molecular O-H⋯O hydrogen bond with the hydroxyl functionality. In the crystal, molecules are linked into chains along the b axis by N-H⋯O hydrogen bonds.

Rapid Determination of 9 Tyrosine Kinase Inhibitors for the Treatment of Hepatocellular Carcinoma in Human Plasma by QuEChERS-UPLC-MS/MS.

A reliable and rapid method employing QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) pretreatment coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was successfully developed and validated for the analysis of nine tyrosine kinase inhibitors (TKIs) in human plasma. Biological samples were extracted with acetonitrile and salted out with 350 mg of anhydrous magnesium sulfate (MgSO4), followed by purification with 40 mg of ethyl enediamine-N-propylsilane (PSA) adsorbents. All analytes and internal standards (IS) were separated on the Hypersil GOLD VANQUISH C18 (2.1 mm × 100 mm, 1.9 µM) column using the mobile phases composed of acetonitrile (phase A) and 0.1% formic acid in water (phase B) for 8.0 min. Detection was performed by selection reaction monitoring (SRM) in the positive ion electrospray mode. Lenvatinib, sorafenib, cabozantinib, apatinib, gefitinib, regorafenib, and anlotinib rendered good linearity over the range of 0.1-10 ng/ml, and 1-100 ng/ml for tivantinib and galunisertib. All linear correlation coefficients for all standard curves were ≥ 0.9966. The limits of detection (LOD) and the limits of quantitation (LOQ) ranged from 0.003 to 0.11 ng/ml and 0.01-0.37 ng/ml, respectively. The method was deemed satisfactory with an accuracy of -7.34-6.64%, selectivity, matrix effect (ME) of 90.48-107.77%, recovery, and stability. The proposed method is simple, efficient, reliable, and applicable for the detection of TKIs in human plasma samples as well as for providing a reference for the clinical adjustment of drug administration regimen by monitoring the drug concentrations in the plasma of patients.

Treatment of Cerebral Ischemia Through NMDA Receptors: Metabotropic Signaling and Future Directions.

Excessive activation of N-methyl-d-aspartic acid (NMDA) receptors after cerebral ischemia is a key cause of ischemic injury. For a long time, it was generally accepted that calcium influx is a necessary condition for ischemic injury mediated by NMDA receptors. However, recent studies have shown that NMDA receptor signaling, independent of ion flow, plays an important role in the regulation of ischemic brain injury. The purpose of this review is to better understand the roles of metabotropic NMDA receptor signaling in cerebral ischemia and to discuss the research and development directions of NMDA receptor antagonists against cerebral ischemia. This mini review provides a discussion on how metabotropic transduction is mediated by the NMDA receptor, related signaling molecules, and roles of metabotropic NMDA receptor signaling in cerebral ischemia. In view of the important roles of metabotropic signaling in cerebral ischemia, NMDA receptor antagonists, such as GluN2B-selective antagonists, which can effectively block both pro-death metabotropic and pro-death ionotropic signaling, may have better application prospects.

Methyl 2-(2-{[(benz-yloxy)carbon-yl]amino}-propan-2-yl)-5-hy-droxy-6-oxo-1,6-dihydro-pyrimidine-4-carboxyl-ate.

In the title compound, C(17)H(19)N(3)O(6), the dihedral angle between the two aromatic rings is 45.9 (1)°. The crystal structure is stabilized through inter-molecular N-H⋯O hydrogen bonds and intra-molecular O-H⋯O hydrogen bonds are also present.

[Blackbody radiation of cavitation luminescence from glycerin].

An improved conical bubble sonoluminescence U-tube was built. Using this setup, the spectra and light pulses of conical bubble luminescence in glycerin were detected. Results show that the spectra are continuum, which are well fitted by blackbody radiation. The cavitational temperature ranging from 2 600 to 3 050 K was calculated from the fitted spectra. The reasons for the existence of blackbody radiation in conical bubble luminescence were discussed both from special and temporal sides. The value of radius of cavitational bubble is about 1.7 cm theoretically, which is greater than that of the bubble acoustically excited. The width of light pulses of cavitational bubble reached 40-60 ms, and this provided enough time for the blackbody radiation. In addition, the light pulses at different wavelength were measured, and results show that the width of light pulses increased with the raise of wavelength of spectra, which proved the mechanism of blackbody radiation. Finally, based on the spectra and light pulses, the intensity of luminescence was calculated to be about 0.18 J.

Schizophrenia­associated microRNA­148b­3p regulates COMT and PRSS16 expression by targeting the ZNF804A gene in human neuroblastoma cells.

Zinc finger protein 804A (ZNF804A) has been identified by genome­wide association studies as a robust risk gene in schizophrenia, but how ZNF804A contributes to schizophrenia and its upstream regulation remains unknown. Previous studies have indicated that microRNAs (miRs) are key factors that regulate the expression levels of their target genes. The present study revealed significantly increased expression of miR­148b­3p in the peripheral blood of patients with first­onset schizophrenia compared with healthy controls, and bioinformatics analysis predicted that the ZNF804A gene is a target of miR­148b­3p. Therefore, the present study investigated the possible upstream regulation of ZNF804A by miR­148b­3p in the human neuroblastoma SH­SY5Y cell line, and assessed the implications for schizophrenia. The results revealed significantly reversed expression levels of miR­148b­3p (P=0.0051) and ZNF804A (P=0.0218) in the peripheral blood of patients with first­onset schizophrenia compared with healthy individuals. Furthermore, it was demonstrated that miR­148b­3p directly targeted ZNF804A via binding to conserved target sites in the 3'­untranslated region of ZNF804A mRNA, where it inhibited the endogenous expression of ZNF804A at both the mRNA (P=0.048) and protein levels (P=0.013) in SH­SY5Y cells. Furthermore, miR­148b­3p was revealed to regulate the expression levels of catechol­O­methyltransferase (COMT) and serine protease 16 (PRSS16) by targeting ZNF804A in SH­SY5Y cells. Collectively, the present results indicated that there was a direct upstream regulation of the schizophrenia risk gene ZNF804A by miR­148b­3p, which contributed to the regulation of the downstream genes COMT and PRSS16. Thus, the miR­148b­3p/ZNF804A/COMT/PRSS16 pathway may play an important role in the pathophysiology of schizophrenia, and may serve as a potential target in drug discovery and gene therapy for this disorder.

[The light pulses and spectra of straight tube conical bubble sonoluminescence in glycol].

Based on the U-tube, a new type of sonoluminescence apparatus-conical bubble sonoluminescence straight tube apparatus was set up, and the structures and operations were described detailedly. Using the apparatus, the ultrabright cavitation luminescence was obtained in glycol solution. The light pulses of conical bubble sonoluminescence were detected, results show the half width is about 80 micros that is much longer than the results by ultrasound, which should be caused by the fact that the conical bubble can obtain more energy from the flow than the bubbles from the ultrasound. The spectra consist in a broad background ranging from the ultraviolet region to the visible region, on which five clear sequences of Swan bands and three sequences of B 2sigma+ --> X 2sigma+ transition of CN are superimposed. A band assigned to the A 2delta --> X 2II transition of CH was also measured. Specially, the vibrational structures of Swan bands can be resolved. Finally, the achieved molecular vibrational temperature of C2 is estimated to be about (4 200 +/- 200) K.

[Effect of nebulizer gas pressure on the emission intensity of ICP].

In an attempt to inhance the emission intensity of ICP, a conventional concentric pneumatic nebulizer was used with increased pressure, and the aqueous aerosol was partially let out to modulate the flow velocity of sample solution into the flame of the ICP. In the present work, the emission spectra of elements Ca, Si, Sr and Zn in water samples were measured, and the results showed that corresponding emission intensities are the highest at 0.05 MPa under the conventional condition, and after increasing the nebulizer gas pressure to 0.07 MPa and letting out part of aqueous aerosol, the peak values grew by 38%, 79%, 45% and 70%, respectively. In addition, the stability of the plasma radiation was not affected by the higher nebulizer gas pressure.

Determination of six polyether antibiotic residues in foods of animal origin by solid phase extraction combined with liquid chromatography-tandem mass spectrometry.

A new method using solid phase extraction (SPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of six polyether antibiotics, including lasalocid, salinomycin, monensin, narasin, madubamycin and nigericin residues, in foods of animal origin. The samples were extracted with acetonitrile and purified by ENVI-Carb SPE columns after comparing the impurity effect and maneuverability of several SPE cartridges. Subsequently, the analytes were separated on a Hypersil Gold column (2.1×150mm, 5µm) and analyzed by MS/MS detection. The limit of quantization (LOQ) for milk and chicken was 0.4µg/kg, and for chicken livers and eggs, it was 1µg/kg. The linearity was satisfactory with a correlation coefficient of >0.9995 at concentrations ranging from 2 to 100µg/L. The average recoveries of the analytes fortified at three levels ranged from 68.2 to 114.3%, and the relative standard deviations ranged from 4.5 to 12.1%. The method was suitable for quantitative analysis and confirmation of polyether antibiotic residues in foods of animal origin.

[Effect of the temperature of solution on the emission intensity of ICP].

The effect of solution temperature (20, 40 and 60 degrees C) on the emission intensity of ICP has been studied. The results show that the spectrum intensity of the elements Ba, Cu and Zn increases obviously with increasing the solution temperature. In addition, at different solution temperatures, the rule of the variation of the intensity with both observation height and nebulizer gas pressure has been obtained, which indicates that the best observation location is lowered when increasing the temperature, but the best nebulizer gas pressure is augmented.

Determination of chromium(III) and total chromium in water by derivative atomic absorption spectrometry using flow injection on-line preconcentration with a double microcolumn.

A rapid and sensitive method has been proposed for the sequential determination of chromium(III) and total chromium in water samples by flame atomic absorption spectrometry combined with a flow injection on-line preconcentration on a double-microcolumn. The chromium(III) and total chromium in samples were retained on a double-microcolumn with a cation exchange resin, respectively, and eluted directly into a nebulizer by 3 mol L(-1) HNO3. The characteristic concentration (gives a derivative absorbance of 0.0044) and the detection limit (3sigma) for chromium were 0.512 microg L(-1) and 0.647 microg L(-1) for a preconcentration time of 1 min, respectively. This is an improvement of 20 and 14-times than those of conventional FI-FAAS. The proposed method allows the determination of chromium in the range of 0-90 microg L(-1) with a relative standard deviation of 3.63% at the 10 microg L(-1) level. The method has been applied for the analysis of chromium in reference water of National Research Center for Certified Reference Materials (GBW08607) and other water samples with satisfactory results.

[Determination of chromium(III) and chromium(VI) in water using flow injection on-line preconcentration and separation with flame absorption spectrometric detection].

A rapid and sensitive method for the sequential determination of Cr(III) and Cr(VI) in water samples based on flow injection on-line preconcentration and separation with two-microcolumn system-flame atomic absorption spectrometry has been developed. The Cr(III) and Cr(VI) in water samples were respectively retained in a microcolum with cation exchange resin and in a microcolumn with anion exchange resin and were eluted directly by 15% HNO3 and 8% NH4NO3, respectively. The characteristic concentrations (pre-concentration time of 1 min) for Cr(III) and Cr(VI) were 1.50 micrograms.L-1 and 1.39 micrograms.L-1, respectively, The relative standard deviations at 10 micrograms.L-1 level were 3.41% and 1.80%, and the corresponding detection limits (3 sigma) were 1.03 micrograms.L-1 and 0.54 microgram.L-1, respectively. The satisfactory recovery of 93.48%-107.5% could be obtained from water samples.

Hydride generation for the direct determination of trace and ultra-trace level of arsenic and antimony in waters using derivative atomic absorption spectrometry.

A new method is developed for the direct determination of trace and ultra-trace level of arsenic and antimony in waters by hydride generation derivative atomic absorption spectrometry (DHGAAS). The signal model and fundamentals of DHGAAS are described. The effects of atomization temperature, argon flow rate, acidity and concentration of KBH(4)and KI were investigated and analytical conditions were optimized. The sensitivities for arsenic and antimony were increased 36.4 and 27.6 times better than those of conventional hydride generation atomic absorption spectrometry (HGAAS). For a 2 mV min(-1) sensitivity range setting, the characteristic concentration was 0.003 microg L(-1) for arsenic and 0.004 microg L(-1)for antimony, and the detection limits (3sigma) were 0.015 micro g L(-1) for arsenic and 0.020 microg L(-1) for antimony. The proposed method was applied to the determination of arsenic and antimony in several water samples with satisfactory results.