Ambient mass spectrometry imaging of food natural products by angled direct analysis in real time high-resolution mass spectrometry.

Direct surface analysis in ambient conditions provides information on the position and chemical composition of an object at the time of investigation. An angled sampling probe is developed in this work for direct analysis in real time (DART) ionization high-resolution mass spectrometry. The DART ion source and the interface were modified for improved surface resolution, increased ion transfer efficiency, as well as enabling two-dimensional surface scanning. The angled probe DART-MS system was used for investigating a variety of food samples including fruit peels, ginseng root, plant leaves and sections of radish. Abundant signals and distinct chemical profiles are obtained in seconds, and spatial distribution of different molecules across the sample surfaces can be observed. In addition, the developed system can quickly identify the chemical changes when the surfaces were treated. The method is capable of directly evaluating food sample surfaces with different shapes, hardness, and conditions, without any sample pretreatments.

[HTRF-based high-throughput PGE2 release prohibition model and application in discovering traditional Chinese medicine active ingredients].

Prostaglandin (PG) E2 is an active substance in pathological and physiological mechanisms, such as inflammation and pain. The in vitro high-throughput assay for screening the inhibitors of reducing PEG2 production is a useful method for finding out antiphlogistic and analgesic candidates. The assay was based on LPS-induced PGE2 production model using a homogeneous time-resolved fluorescence(HTRF) PGE2 testing kit combined with liquid handling automation and detection instruments. The critical steps, including the cell density optimization and IC50 values determination of a positive compound, were taken to verify the stability and sensibility of the assay. Low intra-plate, inter-plate and day-to-day variability were observed in this 384-well, high-throughput format assay. Totally 5 121 samples were selected from the company's traditional Chinese medicine(TCM) material base library and used to screen PGE2 inhibitors. In this model, the cell plating density was 2 000 cells for each well; the average IC50 value for positive compounds was (7.3±0.1) µmol; the Z' factor for test plates was more than 0.5 and averaged at 0.7. Among the 5 121 samples, 228 components exhibited a PGE2 production prohibition rate of more than 50%, and 23 components exhibited more than 80%. This model reached the expected standards in data stability and accuracy, indicating the reliability and authenticity of the screening results. The automated screening system was introduced to make the model fast and efficient, with a average daily screening amount exceeding 14 000 data points and provide a new model for discovering new anti-inflammatory and analgesic drug and quickly screening effective constituents of TCM in the early stage.

[Atrial myocytes KChIP2 mRNA expression in rheumatic heart disease patients with atrial fibrillation].

OBJECTIVE: To detect the KChIP2 mRNA level in rheumatic heart disease patients with or without atrial fibrillation (AF) by real-time PCR. METHODS: Right atrial appendage samples from rheumatic heart disease patients with (n = 17) or without AF (n = 13) were obtained during cardiac surgery. Total RNA was extracted from the atrial tissues, and the KChIP2 and Kv4.3 mRNA were detected by SYBR Green I real-time PCR with the GAPDH as the house keeping gene. RESULT: The ratio of KChIP2/GAPDH (0.1468 +/- 0.0452 vs. 0.2200 +/- 0.0388, P<0.01) and the ratio of Kv4.3/GAPDH (0.3946 +/- 0.1826 vs. 0.5257 +/- 0.1427, P<0.05) were significantly lower in AF patients compared to non-AF patients. CONCLUSION: Down-regulated atrial KChIP2 and Kv4.3 mRNA expressions in rheumatic heart disease patients with chronic AF might be one of the molecular bases responsible for the down-regulation of the I(to) current density of AF.