Optimized Synthesis of Silver Nanoparticles by Factorial Design with Application for the Determination of Melamine in Milk

A colorimetric method based on silver nanoparticles was developed for the determination of melamine in milk. Silver nanoparticles were synthesized without any stabilizer, using sodium borohydride as the reducing agent. Optimization of the variables for the formation of the nanoparticles was performed by factorial design, resulting in stable colloidal silver nanoparticles with a mean diameter of 14.0?±?2.7?nm. Spectrophotometric measurements performed at 475?nm showed a linear range from 0.033 to 1.50?mg?L^?1 of melamine with limits of detection and quantification of 0.009 and 0.031?mg?L^?1, respectively. The method provided highly sensitive determination of melamine in milk.     

An Integrative Approach of an In Vitro Measurement of the Digestibility of Triacylglycerols of Human Milk

Several studies have been published regarding the effect of different factors on the digestion of milk lipids, considering their natural structural arrangement as milk fat globules and the efficiency of the digestive enzymes in the lipolysis of such complex structures. During digestion, the lipolytic products are dispersed in vesicles and micelles, which are the source for absorption of digested lipids. Therefore, it is necessary to consider the isolation of the micellar phase from the digesta to appropriately determine the amounts and classes of lipids which are bioaccessible. This study presents an integrative approach that included an isolation procedure to separate the micellar fraction from undigested and non-micellar parts, and the distribution of digested milk lipids in micelles determined directly through chromatographic techniques. Four groups of five full term mothers donated colostrum or mature milk. Two sets of samples were analyzed directly (raw), and two sets were pasteurized and then analyzed. Our data revealed that the profile of digested milk lipids is different depending on the lactation period and processing stage, while the carbon atom number distribution of the digested triacylglycerols in the micellar fraction provides a substantial information regarding the acylglycerols species that are less available for absorption.     

MicroRNAs电化学生物传感器在乳腺癌检测中的研究进展

MicroRNAs是一类内源性非编码小RNA分子,可调控靶基因的表达.特异性microRNAs的失调在诸如癌症、心血管疾病、免疫疾病、神经退行性疾病和皮肤疾病等的发展过程中起着关键作用,常作为疾病早期诊断和预后的生物标志物.电化学生物传感器由于其灵敏、快速、成本低等优势,已经成为传统microRNAs检测方法的一种很有...     

Disposition Kinetics of Amitraz in Lactating Does

Amitraz, a member of the formamidine pesticide family, commonly used for ectoparasite control, is applied as a dip or low-pressure hand spray to cattle and swine, and the neck collar on dogs. Data on amitraz were generated mainly on laboratory animals, hens, dogs, and baboons. The data on the toxicity and disposition of amitraz in animals and its residues in the milk are inadequate. Therefore, the present study was intended to analyze the disposition kinetics of amitraz and its pattern of elimination in the milk of lactating does after a single dermal application at a concentration of 0.25%. Blood at predetermined time intervals and milk twice daily were collected for eight days post application. The drug concentration was assayed by high-performance liquid chromatography (HPLC). Amitraz was detected in whole blood as early as 0.5 h, which attained a peak concentration at 12 ± 5 h, followed by a steady decline; however, detection persisted until 168 h. Amitraz was present in the blood at its 50% C_max even after 48 h, and was still detectable after 7 days. The disposition after a single dermal application was best described non-compartmentally. The mean terminal half-life (t_1/2), mean residence time (MRT), and area under the curve (AUC_0–t) were 111 ± 31 h, 168 ± 39 h, and 539 ± 211 µg/mL/h, respectively. The apparent volume of distribution (Vd_area) was 92 ± 36 mL/g with an observed clearance (Cl) of 0.57 ± 0.33 mL/kg/h. Thus, the drug was well absorbed, widely distributed and slowly eliminated from the animal body. Amitraz achieved milk concentration approximating 0.2 per cent of the total dose after a single exposure and the steady-state elimination of amitraz in milk above the recommended maximum residue limit (MRL) of 0.01 mg/kg can act as a source of public health concern when applied on lactating animals.     

柱前衍生-超高效液相色谱法测定3种奶粉中18种氨基酸

近年来羊奶粉和骆驼奶粉备受消费者青睐,它们具有潜在的低致敏性,因此成为牛乳不耐受人群尤其是婴幼儿的母乳替代品,其营养价值备受关注.牛奶粉、羊奶粉和骆驼奶粉中氨基酸含量的比较研究鲜有报道.利用酸水解得到游离氨基酸,选择6-氨基喹啉-N-羟基琥珀酰亚胺氨基甲酸酯(AQC)进行柱前衍生,超高效液相色谱分离并检测,外标法定量....     

Exploring the mechanism of Cremastra Appendiculata (SUANPANQI) against breast cancer by network pharmacology and molecular docking

BackgroundSUANPANQI, the pseudo phosphorous stem of Cremastra appendiculata, is one of the most well-known traditional Chinese medicine, which has been shown to inhibit tumorigenesis in various human cancers. However, the underlying mechanism of SUANPANQI treatment against breast cancer (BRCA) remains unclear. In this study. we aim to investigate the bioactive compounds and mechanisms of SUANPANQI in the treatment of BRCA based on network pharmacology and molecular docking.MethodsThe compounds were collected from previous research. SwissADME was used to screen bioactive compounds. The targets corresponding to SUANPANQI and BRCA were obtained using MalaCards and SwissTargetPrediction. SUANPANQI-related and BRCA-related targets were found and then overlapped to get intersections, which represented potential anti-BRCA targets of SUANPANQI. The Cytoscape software was used to construct bioactive compounds targeting the BRCA network. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of the targets was extracted from the metascape database, then conducted using the Cluster Profiler package in R software. Protein-Protein interaction (PPI) network was constructed using the STRING online database and analyzed using Cytoscape software. Pivotal genes were screened using the topological analysis, survival analysis, and pathological stage analysis. Molecular docking analysis was used to verify whether the bioactive compounds had a definite affinity with the pivotal targets.ResultsSixty-five bioactive compounds of SUANPANQI were involved with 225 predicted BRCA targets. Then, a compound-target network and a PPI network were constructed. The GO analysis and KEGG enrichment analysis suggested that SUANPANQI worked against BRCA via PI3K-Akt, Ras, FoxO, Rap1, and ErbB signaling pathways, etc. After topological analysis, survival analysis, and pathological stage analysis of the SUANPANQI potential targets against BRCA, 6 pivotal target genes (AR, HSP90AA1, MMP9, PGR, PTGS2, TNF) that were highly responsible for the therapeutic effects of SUANPANQI against BRCA were obtained. Molecular docking results showed that 6 bioactive compounds of SUANPANQI had strong binding efficiency with the 6 pivotal genes.ConclusionsThe present study clarifies the mechanism of SUANPANQI against BRCA through multiple targets and pathways, and provides evidence to support its clinical use.     

Identification of key genes of hesperidin in inhibition of breast cancer stem cells by functional network analysis

Breast cancer therapy with classical chemotherapy is unable to eradicate breast cancer stem cells (BCSCs). Loss of p53 function causes growth and differentiation in cancer stem cells (CSCs); therefore, p53-targeted compounds can be developed for BCSCs-targeted drugs. Previously, hesperidin (HES), a citrus flavonoid, showed anticancer activities and increased efficacy of chemotherapy in several types of cancer in vitro and in vivo. This study was aimed to explore the key protein and molecular mechanism of hesperidin in the inhibition of BCSCs using bioinformatics and in vitro study. Bioinformatics analysis revealed about 75 potential therapeutic target proteins of HES in BCSCs (TH), in which TP53 was the only direct target protein (DTP) with a high degree score. Furthermore, the results of GO enrichment analysis showed that TH was taken part in the biological process of regulation of apoptosis and cell cycle. The KEGG pathway enrichment analysis also showed that TH is involved in several pathways, including cell cycle, p53 signaling pathway. In vitro experiment results showed that HES inhibited cell proliferation, mammosphere, and a colony formation, and migration in on MCF-7 3D cells (mammospheres). HES induced G0/G1 cell cycle arrest and apoptosis in MCF-7 cells 3D. In addition, HES treatment reduced the mRNA level of p21 but increased the mRNA level of cyclin D1 and p53 in the mammosphere. HES inhibits BCSCs in mammospheres. More importantly, this study highlighted p53 as a key protein in inhibition of BCSCs by HES. Future studies on the molecular mechanism are needed to validate the results of this study.     

The regulation of microRNA in each of cancer stage from two different ethnicities as potential biomarker for breast cancer

miRNA has recently emerged as a potential biomarker for breast cancer. Even though many studies have identified ethnic variation affecting miRNA regulation, the effect of cancer stage within specific ethnicities on miRNA epigenetic remains unclear. The present study is designed to investigate miRNA regulation from two distinct ethnicities in specific cancer stages (non-Hispanic white and non-Hispanic black) using the TCGA dataset. Differentially expressed miRNAs were calculated by using the edgeR package. miRNAs with the highest or lowest log fold Change from each cancer stage were selected as a potential biomarker. miRNA-gene interaction was analyzed by using spearman correlation analysis, CLUEGO, and DIANA-mirpath. The association of biomarker candidates with diagnostic and prognostic performance was assessed using ROC and Kaplan-Meier survival analysis. miRNA-gene interaction analysis revealed the involvement of selected miRNAs in cancer progression. From eleven selected aberrant miRNAs, four of the miRNAs (hsa-mir-495, hsa-mir-592, hsa-mir-6501, and hsa-mir-937) are significantly detrimental to breast cancer diagnosis and prognosis. Hence, our result provides valuable information to explore miRNA’s role in each cancer stage between non-Hispanic white and non-Hispanic black.     

Bacteria and cancer cell pearl chain under dielectrophoresis

In this work, we aim to observe and study the physics of bacteria and cancer cells pearl chain formation under dielectrophoresis (DEP). Experimentally, we visualized the formation of Bacillus subtilis bacterial pearl chain and human breast cancer cell (MCF-7) chain under positive and negative dielectrophoretic force, respectively. Through a simple simulation with creeping flow, AC/DC electric fields, and particle tracing modules in COMSOL, we examined the mechanism by which bacteria self-organize into a pearl chain across the gap between two electrodes via DEP. Our simulation results reveal that the region of greatest positive DEP force shifts from the electrode edge to the leading edge of the pearl chain, thus guiding the trajectories of free-flowing particles toward the leading edge via positive DEP. Our findings additionally highlight the mechanism why the free-flowing particles are more likely to join the existing pearl chain rather than starting a new pearl chain. This phenomenon is primarily due to the increase in magnitude of electric field gradient, and hence DEP force exerted, with the shortening gap between the pearl chain leading edge and the adjacent electrode. The findings shed light on the observed behavior of preferential pearl chain formation across electrode gaps.     

离子色谱法测定乳粉中的高氯酸盐

建立了乳粉中痕量高氯酸盐的固相萃取离子色谱分析方法。在碱性条件下,乙腈提取、浓缩,0.22μm尼龙滤膜+RP柱净化,AS20阴离子分析柱(150mm×4.0mm)分离,流动相为氢氧化钠溶液(30~70mmol/L),流速1.0mL/min。结果表明,高氯酸盐在0.4~20μg/L内具有良好的线性关系,相关系数0.999 8,样品检出限20μg/kg,加标回收率在77.2%~108%。测定了41个乳粉中的高氯酸盐含量,高氯酸盐检出率为31.7%。对质监部门用来检测乳粉中高氯酸盐的方法是一个补充,为食品安全提供了参考数据。