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C. officinalis Kuan is the dry root of Cyathula officinalis Kuan. Clinically, it is used for fall and flutter injury, rheumatism and arthralgia. Phytoecdysteroids have significant anti-inflammatory effects, and the phytoecdysteroids present in C. officinalis Kuan exhibit potential for treating rheumatoid arthritis. This study first developed a selective, accurate and efficient LC-MS/MS method for 12-day pharmacokinetic studies regarding the simultaneous determination of cyasterone, 25-epi-28-epi-cyasterone, precyasterone and capitasterone from C. officinalis Kuan phytoecdysteroids extract in normal and adjuvant arthritis rats. An Agilent Eclipse Plus C18 RRHD column (1.8 µm, 50mm × 2.1 mm) with a gradient mobile phase consisting of water (A) and acetonitrile (B) was used for analysis. The mass analysis was performed in an Agilent 6430 QQQ-MS mass spectrometer with positive mode multiple reaction monitoring (MRM). The results indicated that the AUC0-t and AUC0-∞ values of the four phytoecdysteroids in adjuvant arthritis rats were different from those in normal rats on the first day, which could provide a helpful reference for pharmacological and toxicological studies, as well as clinical applications of C. officinalis Kuan in the treatment of rheumatoid arthritis. 1. C. officinalis Kuan is the dry root of Cyathula officinalis Kuan which has been used for the treatment of flapping injury, rheumatism arthralgia, foot flaccidity, and tendon contracture thousands of years in China, and has been officially included in the Chinese Pharmacopoeia. 2. A highly accurate, stable, and sensitive ultra-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method was first established and validated for simultaneously determination four phytoecdysteroids: cyasterone, 25-epi-28-epi-cyasterone, precyasterone and capitasterone in normal and adjuvant arthritis rats plasma samples 12 days of continuous gavage of C. officinalis Kuan phytoecdysteroids extract. 3. The phytoecdysteroids is the important component of C. officinalis Kuan, which is difficult to separated. And there is no report for the pharmacokinetic study of phytoecdysteroids from C. officinalis Kuan. And the method provides a good reference for the follow-up studies clinical medication of the phytoecdysteroids from C. officinalis Kuan. [ABSTRACT FROM AUTHOR]

In this paper, the asynchronous l 2 − l ∞ filtering problem is directed at a kind of discrete-time impulsive switched systems, where 'asynchronous' implies that there is a delay when switching occurs between filter modes and system modes. A novel Lyapunov function has been constructed. The inventiveness lies in discontinuity of Lyapunov-like function at both the switching time and the instant when the system modes and filter modes are matched. An improved inequality portraying the relationship among Lyapunov-like function, impulse, asynchronous phenomena and disturbance is built to pledge the l 2 − l ∞ performance. On the basis of directed graph, the novel Lyapunov function, the improved inequality and admissible edge-dependent average dwell time technology, some criteria suitable for proving the globally uniformly exponential stability of filtering error system are proposed with l 2 − l ∞ performance index, and the relevant filter can also be designed. Finally, three numerical examples show the availability of the obtained conclusions. [ABSTRACT FROM AUTHOR]

Pregnane X receptor (PXR) as a ligand dependent transcription factor, is capable of regulating gene expression of cytochromes P450 and transporters involved in xenobiotic/drug metabolism and elimination. Due to the species differences in the regulatory specificity of PXR, gene regulation should not be extrapolated from mammal to fish without research data. The aim of present study was to investigate the effect of 27 natural products on PXR, CYP3A30 and MDR1 genes in channel catfish (Ietalurus punetaus) kidney cells (CC-K). The results showed that bisdemethoxycurcumin, glycyrrhetnic acid, rotenone, artemisinin, dihydroartemisinin, ligustilide and matrine strongly induced the mRNA levels of PXR. Additionally, the up-regulation of CYP3A30 gene ran parallel with PXR gene after the treatment of demethoxycurcumin, glycyrrhetnic acid, artemisinin, matrine, baicalein, schisantherin A, ligustilide, and dihydroartemisinin. Moreover, we found that natural products schisandrin A, schisandrin B, schisandrol A, and schisandrol B significantly up-regulated the mRNA level of MDR1 gene. Our work with a view to provide experimental data support for further research, which will make for the rational application of natural products in channel catfish, such as to avoid adverse herb-drug interactions or accelerating the residue elimination of chemical medicine. [ABSTRACT FROM AUTHOR]

The residue depletion of niclosamide (NIC) in freshwater fish including blunt snout bream (Megalobrama amblycephala), yellow catfish (Pelteobagrus fulvidraco) and channel catfish (Ietalurus Punetaus) were investigated under laboratory conditions. NIC concentrations in fish were determined by Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) with heated electrospray ionisation. The mean recoveries were in the range of 75.5-98.5%, with relative standard deviations ranging from 1.0 to 9.4%. The depletion results showed that the long half-life of NIC was 8.8-22.1 days. Risk assessment of NIC residue in edible tissues (muscle and skin) of the three species of freshwater fish was performed using the quotient (RQ), because of no maximum residue limit (MRL) has been set for NIC in fish. The results demonstrated that the RQ values were all significantly lower than 1. Therefore, the effect of NIC residues in the three species of freshwater fish at the immersion concentration was negligible to Chinese people. [ABSTRACT FROM AUTHOR]

Context: Liquid-liquid extraction (LLE) shows high efficiency in the plasma sample preparation. However, this extraction method is not optimal for the biological samples containing complex organic interferences, such as liver and brain tissues. Some plant secondary metabolites can be converted between water-insoluble and water-soluble forms by pH adjustment. Objective: A two-step pH-dependent LLE method was introduced in this study to eliminate both water-soluble and lipidic interferences using the properties of pH-dependent interconvertible forms of analytes during sample preparation. A sensitive and reliable method using a reverse-phase HPLC coupled with a fluorescence detector was developed and validated. Materials and methods: 10-Hydroxycamptothecin (HCPT) with internal standard camptothecin and liver tissues were used as model compounds and biological samples. The lactone form of HCPT was converted to the water-soluble carboxylate form under moderate alkaline conditions, and the water-insoluble interferences were extracted with a nonpolar solvent. Afterward, the water-insoluble lactone form of HCPT was regenerated by acidification and then extracted using an organic solvent in a second LLE step. Results: The calibration curve was linear ( r2 > 0.999) for HCPT concentrations ranging from 2.5 to 160 ng/mL. The mean recoveries of HCPT were 114.94 ± 3.98, 104.30 ± 2.44 and 95.90 ± 1.40% ( n = 6) at concentrations of 2.5, 10 and 80 ng/mL, respectively. The stability determination data showed that no significant degradation occurred under the experimental conditions. This method was successfully applied to liver tissue distribution study of HCPT in mice. Discussion and conclusion: This two-step LLE can be applied to distribution studies of compounds with pH-dependent interconvertible forms in other biological matrices. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome ofElaphe carinatawas sequenced and analysed using muscle tissue for the first time. The genome is 17 154 bp in length. The complete mitochondrial genome contains 22 tRNA genes, 13 protein-coding genes (PCGs), two rRNA genes, two control regions (CRI and CRII) and one putative origin of L-strand replication. The gene order and nucleotide composition ofE. carinataare very similar withE. davidi, E. schrenckii,E. anomalaandE. bimaculata.A phylogenetic tree of mitochondrial genomes analyses of 16 species snakes of Colubridae was made based on the Neighbour-Joining (NJ) method,E. carinatahas the most closely relationship withE. davidi, whileE. poryphyraceaandEuprepiophis perlaceaare special species. [ABSTRACT FROM PUBLISHER]