QuEChERS-超高效液相色谱-串联质谱法同时测定畜禽组织中6种黄曲霉毒素和杂色曲霉素

建立了QuEChERS前处理技术结合超高效液相色谱-串联质谱（UHPLC-MS/MS）检测畜禽组织中6种黄曲霉毒素和杂色曲霉素残留的分析方法。样品经20 μL β-葡萄糖苷酶酶解和10 mL乙腈-水（84：16,v/v）提取,然后用1.0 g氯化钠和1.0 g无水硫酸镁净化、5 mL正己烷脱脂,最后采用1 mL含5 mmol/L乙酸铵的乙腈-水溶液（80：20,v/v）复溶。以甲醇和5 mmol/L乙酸铵为流动相,在多反应监测正离子模式下进行检测,采用基质匹配标准曲线外标法进行定量分析。结果显示,6种黄曲霉毒素和杂色曲霉素在各自的范围内线性关系良好,相关系数（R²）>0.99,检出限（LOD,S/N=3）为0.007~0.30 μg/kg,定量限（LOQ,S/N=10）为0.02~0.91 μg/kg,加标回收率为77.3%~118.5%（n=6）。该法简单、快速,灵敏度高,适用于不同畜禽产品中6种黄曲霉毒素和杂色曲霉素的确证分析。     

3D Bioprinting of Artificial Tissues: Construction of Biomimetic Microstructures

It is promising that artificial tissues/organs for clinical application can be produced via 3D bioprinting of living cells and biomaterials. The construction of microstructures biomimicking native tissues is crucially important to create artificial tissues with biological functions. For instance, the fabrication of vessel‐like networks to supply cells with initial nutrient and oxygen, and the arrangement of multiple types of cells for creating lamellar/complex tissues through 3D bioprinting are widely reported. The current advances in 3D bioprinting of artificial tissues from the view of construction of biomimetic microstructures, especially the fabrication of lamellar, vascular, and complex structures are summarized. In the end, the conclusion and perspective of 3D bioprinting for clinical applications are elaborated.     

高效液相-电喷雾串联质谱法测定动物肌肉组织中的糖皮质激素

本实验建立了肌肉组织中氢化可的松、可的松、泼尼松和地塞米松含量的高效液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)检测方法.样品经酶水解、乙酸乙酯提取、HLB固相萃取净化,C8色谱柱分离,在多反应选择性监测模式(MRM)下采用负离子模式进行信号采集和测定.4种糖皮质激素的检出限为0.13 ～0.25 μg/kg,定量限为0.25 ～ 0.5 μg/kg.在0.5～50.0 μg/L范围内具有良好的线性关系(R2＞0.99).在0.5,5.0和10.0μg/kg基质加标水平下,4种物质的平均回收率为74.0％ ～ 101.8％,相对标准偏差0.7％ ～8.6％.     

Determination of dimetridazole and metronidazole in poultry and porcine tissues by gas chromatography-electron capture negative ionization mass spectrometry

A sensitive and selective method using gas chromatography-electron capture negative ionization mass spectrometry (GC-ECNI-MS) for analysis of dimetridazole (DMZ) and metronidazole (MNZ) in poultry muscles, porcine kidney and liver, and chicken liver, was developed and validated for the purpose of food surveillance testing of the residues of these two nitroimidazoles in various types of animal tissues in the Hong Kong Special Administrative Region. Before homogenization and extraction with toluene, [2H₃]dimetridazole-(DMZ-d³) and secnidazole (SNZ) were added to tissue samples as internal standards. The organic extracts were mixed with n-hexane and subject to solid-phase extraction cleanup by amine extraction columns. MNZ and SNZ were derivatized with BSA prior to GC-ECNI-MS determination. Good recovery and precision were obtained and the limit of detection was below parts per billion levels for poultry and porcine tissues. The method could also be applied for the detection of the hydroxylated metabolite of DMZ.     

Trace elements in human cancerous and healthy tissues: A comparative study by EDXRF,TXRF, synchrotron radiation and PIXE

It is known that trace elements play an important role in a number of biological processes. These include the activation or inhibition of enzymatic reactions, competition between elements and metal proteins for binding positions and modifications in the permeability of cellular membranes. These elements may also influence carcinogenic processes, thus the knowledge of trace element concentrations in healthy and neoplastic tissues might help in diagnostic and in the etiology and development of cancer.     

Advances in Fourier transform infrared (FTIR) spectroscopy of biological tissues

This article reviews some of the recent advances on FTIR spectroscopy in areas related to natural tissues and cell biology. It is an update on our previously published review on the applications of spectroscopic methods employed for the analysis of biological molecules, and summarizes some of the most widely used peak frequencies and their assignments. The aim of this review is to update and consolidate our previously published spectral database, which will help researchers in defining the chemical structure of the biological tissues introducing most of the important peaks present in the natural tissues more precisely and accurately. In spite of applying different methods, there seems to be a considerable similarity in defining the peaks of identical areas of the FTIR spectra. As a result, it is believed that preparing a unique collection of the frequencies encountered in FTIR spectroscopic studies can provide substantial help for future studies. In this article, we have included recent studies that have been reported since previous publication that will be of considerable assistance and added value to those who are focusing their research on defining chemical pathway to the progression of different diseases.     

加速溶剂萃取-液相色谱-质谱/质谱法分析动物组织中的壬基酚、辛基酚和双酚A

建立了测定内分泌干扰物质烷基酚、双酚A的液相色谱-电喷雾串联质谱(负离子模式)分析方法,优化了样品前处理方法。以二氯甲烷作提取溶剂,采用加速溶剂萃取法萃取动物组织样品,萃取液用500 mg OASIS氨基固相萃取柱进行浓缩净化。对流动相组分和流动相添加剂对质谱的离子化效率进行了考察,测得3种化合物在高、中、低3个添加水平的回收率为88%~101%,相对标准偏差小于15%;双酚A、壬基酚和辛基酚的方法检出限分别为0.3, 0.05和0.1 μg/kg。对从北京市场上采集的27份动物组织样品进行检测,结果表明壬基酚广泛存在于各种动物源性食品中,检出含量为0.49~55.98 μg/kg,其中鱼肉组织中都检出壬基酚,而且其含量也较高(9.13~55.98 μg/kg)。     

Differentiating characteristic microstructural features of cancerous tissues using Mueller matrix microscope

Polarized light imaging can provide rich microstructural information of samples, and has been applied to the detections of various abnormal tissues. In this paper, we report a polarized light microscope based on Mueller matrix imaging by adding the polarization state generator and analyzer (PSG and PSA) to a commercial transmission optical microscope. The maximum errors for the absolute values of Mueller matrix elements are reduced to 0.01 after calibration. This Mueller matrix microscope has been used to examine human cervical and liver cancerous tissues with fibrosis. Images of the transformed Mueller matrix parameters provide quantitative assessment on the characteristic features of the pathological tissues. Contrast mechanism of the experimental results are backed up by Monte Carlo simulations based on the sphere–cylinder birefringence model, which reveal the relationship between the pathological features in the cancerous tissues at the cellular level and the polarization parameters. Both the experimental and simulated data indicate that the microscopic transformed Mueller matrix parameters can distinguish the breaking down of birefringent normal tissues for cervical cancer, or the formation of birefringent surrounding structures accompanying the inflammatory reaction for liver cancer. With its simple structure, fast measurement and high precision, polarized light microscope based on Mueller matrix shows a good diagnosis application prospect.     

Solving inverse scattering problems in biological samples by quantitative phase imaging

Quantitative phase imaging (QPI), a method that precisely recovers the wavefront of an electromagnetic field scattered by a transparent, weakly scattering object, is a rapidly growing field of study. By solving the inverse scattering problem, the structure of the scattering object can be reconstructed from QPI data. In the past decade, 3D optical tomographic reconstruction methods based on QPI techniques to solve inverse scattering problems have made significant progress. In this review, we highlight a number of these advances and developments. In particular, we cover in depth Fourier transform light scattering (FTLS), optical diffraction tomography (ODT), and white‐light diffraction tomography (WDT).

     

Quantitative analysis of clavulanic acid in porcine tissues by liquid chromatography combined with electrospray ionization tandem mass spectrometry

The purpose of this study was to develop and validate a method for the determination of clavulanic acid (CLAV) residues in edible tissues of swine by liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS). After a simple extraction of CLAV using an aqueous phosphate buffer solution of pH 6.0, an ultrafiltration step was performed for protein removal. Chromatography of CLAV and the internal standard tazobactam (TAZO) was achieved on a reversed-phase PLRP-S polymeric column (150 mm × 2.1 mm i.d., 100 Å) using a mixture of 0.05 (v/v)% formic acid in water and acetonitrile. The mass spectrometer was operated in the MS/MS selected reaction monitoring (SRM) mode. The method was validated for the analysis of porcine muscle, skin plus fat, liver and kidney, according to the requirements defined by the European Community. Calibration curves were prepared for all tissues and good linearity was achieved over the concentration ranges tested (correlation coefficient ≥0.99 and goodness-of-fit coefficient ≤10%). Limits of quantification of 50 ng g⁻¹ were obtained for the analysis of CLAV in the various tissues which corresponds in all cases to at least half the maximum residue limits (MRLs). Limits of detection ranged between 8.0 and 15.14 ng g⁻¹. The within-day, between-day precisions and trueness fell within the ranges specified in the EMEA/CVMP/573-00/FINAL document. Biological samples from pigs that received an oral or intravenous bolus of a commercial amoxicillin/clavulanic acid formulation were analyzed using the described method.