牛奶中全氟烷酸与全氟磺酸前体物质超高效液相色谱-串联质谱测定方法的研究

目的建立超高效液相色谱-串联三重四级杆质谱(UPLC-MS/MS)测定牛奶基质中11种全氟烷酸与全氟磺酸前体物质的方法。方法牛奶中的目标化合物经过乙腈超声提取后,过固相萃取柱(Waters Oasis@WAX6cc)进行净化,9%氨水-甲醇洗脱。经Waters ACQUITYTMBEH C18色谱柱(50 mm×2.1 mm,1.7μm)分离,在电喷雾负离子源和多反应监测模式下进行测定,采用内标法进行定量分析。结果 11种目标化合物3个添加水平的加标回收率为66.9%~118.1%;相对标准偏差为1.1%~15.3%;检出限为0.5~10 pg/ml;定量限为1~20 pg/ml。对6份市售牛奶样本进行目标化合物的检测,4份样品中检测出2H-全氟-2-癸烯酸,浓度范围为LOD~2.69pg/ml,3份样品中检测出1H,1H,2H,2H-全氟辛基-2-磷酸盐,浓度范围为LOD~32.07 pg/ml。结论本方法简单、快速,准确度和灵敏度高,适用于牛奶基质中全氟烷酸与全氟磺酸前体物质的检测。     

Development of near real-time monitoring systems for some serine protease enzymes in the industrial atmosphere

Rapid, sensitive and reusable assay systems have been developed which can be used for near real-time monitoring of some protease enzymes in the workplace. The systems are based on fluorescence measurement with flow analysis using a mini-bioreactor containing a chemically immobilized fluorophore-labelled protein substrate. Protease enzymes such as subtilisin digest the fluoro-substrate and release fluorescent fragments which are detected downstream by a fluorimeter. The assay systems were optimized and used for measurement of standard solutions of protease enzymes and enzyme-spiked non-biological detergent solutions. These exhibited satisfactory performance in terms of speed, sensitivity, reproducibility and linearity. Detection is fast with response times of 4–5 min. The relationship between the enzyme (subtilisin) concentration and the observed fluorescence signal is linear within the measured range (0–20 ng for a flow injection analysis system and 0–20 ng ml⁻¹ for a simulated air sampling open-loop system). For the latter system using a bioreactor with 0.9 ml immobilized matrix, the limit of detection at 95% confidence is 0.26 ng ml⁻¹. The signal is reproducible with s_r of 0.93% (n = 8) for continuous use over a 16 h period with repeated exposure to 2 ng ml⁻¹ subtilisin episodes.     

PLGA-coated methylene blue nanoparticles for photoacoustic imaging and photodynamic/photothermal cascaded precisely synergistic therapy of tumor

Photodynamic therapy (PDT) and photothermal therapy (PTT) are synergetic treatment strategies in antitumor treatment to achieve the best anticancer efficacy. Although traditional photosensitizer materials such as methylene blue (MB) have been widely studied for PDT, the photothermal effect is rarely reported. Herein, mono-component nanoparticles lactic-co-glycolic acid-coated methylene blue (MBNPs) based on methylene blue (MB) and lactic-co-glycolic acid (PLGA) were prepared by a facile solution-based emulsification method at room temperature. The resulting nanoparticles possess high photothermal conversion efficiency and excellent photodynamic effect. For the first time, the in vitro and in vivo tests indicated an enhanced antitumor efficacy for MBNPs with combined PDT and PTT. This study provides an efficient approach to fabricate nano-MB and also demonstrates the great potential of lactic-co-glycolic acid-coated MB for biomedical applications. Most importantly, the strong tumor growth inhibition by synergistic PTT and PDT demonstrates an excellent cascaded synergistic effect of MBNPs for the tumor therapy.

Photodynamic therapy (PDT) and photothermal therapy (PTT) are synergetic treatment strategies in antitumor treatment to achieve the best anticancer efficacy.     

Application of the margin of exposure (MoE) approach to substances in food that are genotoxic and carcinogenic: EXAMPLE 12: Sudan I (CAS No. 842-07-9)

Sudan I is generally considered mutagenic based on various in vitro and in vivo tests and is carcinogenic in the rat. Dose-response modelling of the data for hepatocellular adenomas in male rats gave a BMDL₁₀ of 7.3 mg/kg-bw/day. Sudan I is an unauthorised substance that might be present in food intermittently. The great variability and uncertainties in the human exposure data which are country specific, depending on consumption patterns and methodology used, resulted in a large range of MOE values (from 30 to 2,000,000).     

Evaluation de deux trousses de dosage de l'érythropoïétine : comparaison avec la technique IRMA Epo Coatria (BioMérieux)

Evaluation of two assays of erythropoïetin: comparison with the IRMA coated kit Epo Coatria (BioMérieux). The aim of this work is to present the results obtained in two groups of patients, with the chemiluminescence method (Advantage automate) and with the ELISA Quantikine IVD kit in comparison with the IRMA (BioMérieux) coated assay, which is the reference method of the laboratory. The statistic tests show an important overlap between the reference group values and those of the polycytemia group (p = 0,45) with the chemiluminescence test. The correlation between ELISA and IRMA methods is quite good (r² = 0,714) and allows us to ensure the transfer of our results, especially in the case of polycytemia vera.     

Developmental toxicity of perfluorononanoic acid in mice

Perfluorononanoic acid (PFNA) is a ubiquitous and persistent environmental contaminant. Although its levels in the environment and in humans are lower than those of perfluorooctane sulfonate (PFOS) or perfluorooctanoic acid (PFOA), a steady trend of increases in the general population in recent years has drawn considerable interest and concern. Previous studies with PFOS and PFOA have indicated developmental toxicity in laboratory rodent models. The current study extends the evaluation of these adverse outcomes to PFNA in mice. PFNA was given to timed-pregnant CD-1 mice by oral gavage daily on gestational day 1–17 at 1, 3, 5 or 10 mg/kg; controls received water vehicle. Dams given 10 mg/kg PFNA could not carry their pregnancy successfully and effects of this dose group were not followed. Similar to PFOS and PFOA, PFNA at 5 mg/kg or lower doses produced hepatomegaly in the pregnant dams, but did not affect the number of implantations, fetal viability, or fetal weight. Mouse pups were born alive and postnatal survival in the 1 and 3 mg/kg PFNA groups was not different from that in controls. In contrast, although most of the pups were also born alive in the 5 mg/kg PFNA group, 80% of these neonates died in the first 10 days of life. The pattern of PFNA-induced neonatal death differed somewhat from those elicited by PFOS or PFOA. A majority of the PFNA-exposed pups survived a few days longer after birth than those exposed to PFOS or PFOA, which typically died within the first 2 days of postnatal life. Surviving neonates exposed to PFNA exhibited dose-dependent delays in eye opening and onset of puberty. In addition, increased liver weight seen in PFNA-exposed offspring persisted into adulthood and was likely related to the persistence of the chemical in the tissue. Evaluation of gene expression in fetal and neonatal livers revealed robust activation of peroxisome proliferator-activated receptor-alpha (PPARα) target genes by PFNA that resembled the responses of PFOA. Our results indicate that developmental toxicity of PFNA in mice is comparable to that of PFOS and PFOA, and that these adverse effects are likely common to perfluoroalkyl acids that persist in the body.     

Rapid and Sensitive Chemiluminescent Enzyme Immunoassay for the Determination of NeomycinResidues in Milk

正Immunoassays greatly contribute to veterinary drug residue analysis.However,there are few reports on detecting neomycin residues by immunoassay.Here,a rapid and sensitive chemiluminescent enzyme immunoassay(CLIEA)was successfully developed for neomycin residue