浙南山区肉用牛羊肝脏中药物残留、重金属蓄积现状及成因探究

目的评估浙南山区肉用牛羊肝脏中代表性农药、兽药及重金属元素蓄积情况,并分析成因。方法对来源于浙南山区的162户肉用牛羊养殖场的肝脏中倍硫磷等25种代表性农药、磺胺二甲嘧啶等24种代表性兽药及铅等3种代表性金属元素的残留进行检测,并对从这些养殖场抽取的325份饲草样本开展相应的农药残留和金属元素含量分析。结果162份牛羊肝脏样本中除13份检出除联苯菊酯外,未检出其他农兽药残留,农兽药残留合格率100%,但6份不同来源的牛羊肝脏样本铅或镉残留量不符合食品中污染物限量要求,不符合率为3.7%。在肝脏联苯菊酯呈阳性的场点发现4批次饲草中存在低浓度联苯菊酯残留,牛羊饲草混合物中铜、铅、镉整体水平分别为5.40~8.30mg/kg、0.21~1.53mg/kg和低于0.074mg/kg。结论浙南山区肉用牛羊的肝脏中药物残留符合限量求,检出的联苯菊酯、铅、镉等与其饲草呈正相关。

DMDD与索拉非尼联合应用协同抑制肝癌细胞恶性生物学行为的实验研究

目的:探讨中药杨桃根提取物DMDD单体(2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione)与索拉非尼联合应用对人肝癌Huh7细胞恶性生物学行为的影响及可能的机制。方法:实验分4组:Huh7细胞对照组、DMDD组、索拉非尼组及DMDD与索拉非尼联合应用组(简称联合应用组)。CCK-8法检测Huh7细胞活力,以金氏公式判定协同效应;平板克隆实验检测Huh7细胞的集落形成能力;划痕实验、Transwell迁移实验和侵袭实验检测Huh7细胞的迁移能力和侵袭能力;流式细胞术检测Huh7细胞周期;RT-qPCR和Western blot检测丝氨酸合成通路中的PHGDH mRNA转录水平和蛋白表达水平。结果:平板克隆实验、划痕实验和Transwell迁移实验结果显示,与Huh7细胞对照组、DMDD组、索拉非尼组比较,DMDD和索拉非尼联合应用组对Huh7细胞增殖、迁移和侵袭能力的抑制作用显著增强(均P<0.05),经金氏公式计算,2、4、8μmol/L DMDD分别联合1、2、4μmol/L索拉非尼具有协同作用(Q>1.15),6、10μmol/L DMDD分别联合3、5μmol/L索拉非尼具有相加作用(0.85<Q<1.15);流式细胞周期检测显示,各组药物干预48 h后,对照组、DMDD组、索拉非尼组及联合应用组G2/M期细胞比例分别为(10.63±0.32)%、(35.77±1.22)%、(30.03±2.22)%、(38.97±0.60)%。与对照组比较,3个组的G2/M期细胞比例均显著上升(均P<0.0001),与索拉非尼组比较,联合应用组G2/M期细胞比例显著上升(P<0.0001)。RT-qPCR和Western blot结果显示,DMDD与索拉非尼联合应用可显著抑制PHGDH的mRNA转录水平和蛋白表达水平(P<0.05)。结论:DMDD与索拉非尼联合应用具有协同增效作用,可协同抑制Huh7细胞的增殖、侵袭和迁移能力,其机制与协同抑制丝氨酸合成通路中的PHGDH的基因转录和蛋白表达有关。

Experimental study on the synergistic inhibition of malignant biological behavior of hepatocellular carcinoma cells by the combination of DMDD and sorafenib

Objective:To investigate the effects and possible mechanisms of the combination of DMDD(2-dodecyl-6-methoxycyclohexa-2-5-diene-1-4-dione),a traditional Chinese medicine monomer,and sorafenib on the malignant biological behavior of human hepatocellular carcinoma Huh7 cells.Methods:The experiment was divided into four groups:Huh7 cells control group,DMDD group,sorafenib group and DMDD and sorafenib combination group.The CCK-8 assay was used to measure the viability of Huh7 cells,and the Kim's formula was used to determine the synergistic effect.The plate cloning experiment was conducted to test colony formation ability of Huh7 cells.The scratch and Transwell experiments were performed to evaluate the migration ability and the invasion ability of Huh7 cells.The cell cycle of Huh7 cells was detected by flow cytometry.RT-qPCR and Western blot were used to measure the mRNA transcription level and protein expression level of PHGDH in the serine synthesis pathway.Results:The plate cloning experiment,scratch experiment,and Transwell migration experiment showed that the combined application of DMDD and Sorafenib significantly enhanced the inhibitory effect on the proliferation,migration,and invasion ability of Huh7 cells compared to the control group,DMDD group,and Sorafenib group(P<0.05).According to the Kim's formula,the combination of DMDD(final concentrations of 2,4,8μmol/L)and Sorafenib(final concentrations of 1,2,4μmol/L)had a synergistic inhibitory effect on the proliferation of Huh7 cells(Q>1.15).6,10μmol/L DMDD combined with 3,5μmol/L Sorafenib showed additive effect.The cell cycle of Huh7 cells was detected by flow cytometry,and the results showed that after 48 hours of drug intervention,the proportion of G2/M phase cells in the control group,DMDD group,Sorafenib group,and combination group were(10.63±0.32)%,(35.77±1.22)%,(30.03±2.22)%,and(38.97±0.60)%,respectively.Compared with the control group,the proportion of G2/M phase cells in the three groups significantly increased(P<0.0001).Compared with the Sorafenib group,the proportion of G2/M phase cells in the combination group significantly increased(P<0.0001).RT-qPCR and Western blot results showed that the combined application of DMDD and Sorafenib significantly inhibited the mRNA transcription level and protein expression level of PHGDH(P<0.05).Conclusion:The combined application of DMDD and Sorafenib has a synergistic effect that can enhance the inhibitory effect on the proliferation,invasion,and migration ability of Huh7 cells.The mechanism of this effect is related to the synergistic inhibition of the gene transcription and protein expression of PHGDH in the serine synthesis pathway.

新型冠状病毒的研究进展

由于新型冠状病毒(SARS-CoV-2)传播快,病情潜伏期长,且具有较强的传染性,引发了全球新型冠状病毒肺炎(COVID-19)疫情的爆发。SARS-CoV-2与重症急性呼吸综合征冠状病毒(SARS-CoV)、中东呼吸系统综合征冠状病毒(MERS-CoV)的基因序列、传播途径、临床特征等方面具有高度相似性,但其传染性、变异性和适应性更强。SARS-CoV-2主要传播途径为呼吸道传播、气溶胶和接触传播。SARS-CoV-2通过表面S蛋白入侵表面有ACE2受体的细胞,通常最先攻击肺,亦可波及心脏、血管、肾脏、肠道和大脑等多个器官。而识别和消除人畜共患病源是阻止新的病毒从动物宿主传染到人类的重要任务,预防和控制SARS-CoV-2感染最有效的措施仍然是早发现、早隔离新的感染源、疑似感染者及无症状感染者,并对感染者进行早期诊断和支持治疗。同时建议建立全球性健康保护体系,统筹安排各种防疫资源,以积极应对现阶段的全球疫情。

水轮发电机磁极匝间短路引起振动的分析和处理

水轮发电机运行振动可主要归类为机械振动和电气振动。介绍土耳其卡亚倍水电站项目在运行时出现的振动现象,找出振动原因分析方法,并进行有效处理。

东萨宏水电站机组过流泄洪模式的实现

老挝东萨宏水电站配备了目前亚洲单机容量最大、世界单机容量第二大的灯泡贯流式机组,电站于2019年11月全部投产发电。电站无常规泄洪措施,采用机组过流泄洪和无闸门非常溢洪道来达到泄洪要求并通过了现场试验。对东萨宏水电站机组过流泄洪模式进行了论述,在考虑安全性的前提下,该模式对节约工程造价,控制上游涌浪,起到了重要的作用。