Adaptation of the ToxRTool to Assess the Reliability of Toxicology Studies Conducted with Genetically Modified Crops and Implications for Future Safety Testing

To determine the reliability of food safety studies carried out in rodents with genetically modified (GM) crops, a Food Safety Study Reliability Tool (FSSRTool) was adapted from the European Centre for the Validation of Alternative Methods’ (ECVAM) ToxRTool. Reliability was defined as the inherent quality of the study with regard to use of standardized testing methodology, full documentation of experimental procedures and results, and the plausibility of the findings. Codex guidelines for GM crop safety evaluations indicate toxicology studies are not needed when comparability of the GM crop to its conventional counterpart has been demonstrated. This guidance notwithstanding, animal feeding studies have routinely been conducted with GM crops, but their conclusions on safety are not always consistent. To accurately evaluate potential risks from GM crops, risk assessors need clearly interpretable results from reliable studies. The development of the FSSRTool, which provides the user with a means of assessing the reliability of a toxicology study to inform risk assessment, is discussed. Its application to the body of literature on GM crop food safety studies demonstrates that reliable studies report no toxicologically relevant differences between rodents fed GM crops or their non-GM comparators.     

短期喂食转基因大豆对雄性大鼠睾丸StAR表达的影响

探讨转基因大豆对雄性大鼠睾丸类固醇激素合成急性调节蛋白(steroidogenic acute regulatory protein,StAR)mRNA水平和蛋白水平表达的影响,为转基因大豆的安全性提供科学依据。将30只健康雄性离乳SD大鼠随机分成两组,设GM组喂食含转CP4-epsps基因大豆饲料,CK组喂食含非转基因受体大豆(Soybean A5403)饲料,喂食试验饲料30,60,90d后,各组随机处死3只大鼠,针对雄性主要生殖器官睾丸、附睾进行脏器系数分析;运用RT-PCR技术检测大鼠睾丸StAR基因表达量;蛋白酶联免疫反应分析大鼠睾丸StAR蛋白含量。喂食30,60,90d后,解剖观察大鼠,与CK组相比GM组大鼠睾丸、附睾形态、颜色正常,大小、器官间比例协调,大鼠睾丸系数无显著性差异,附睾系数除30d处理组(P0.05)差异显著外,其它各处理组间t检验P值均大于0.05,无显著性差异;GM组与CK组大鼠相比,StAR基因相对表达量、蛋白含量相同处理时间组间差异不显著。短期喂食大鼠转CP4-epsps基因大豆,雄性大鼠主要生殖器官睾丸、附睾生长发育正常,喂食转基因大豆对大鼠睾丸中StAR基因表达量、StAR蛋白含量无明显影响。     

大麦芽淀粉碱法提取工艺的研究

以大麦芽为原料,以淀粉提取率为指标,通过碱法提取工艺提取大麦芽淀粉,采用正交试验探讨了搅拌时间、料液比、pH对淀粉提取率的影响,在正交试验的基础上,通过优化得出最佳提取工艺条件为:搅拌时间为3h,料液比为1∶4,pH值为12;在此条件下淀粉的提取率为87.12%。     

UPLC法测定大鼠血浆中藤黄酸葡萄糖酯及其药代动力学研究

目的: 建立测定大鼠血浆中藤黄酸葡萄糖酯浓度的UPLC方法,并探讨其在大鼠体内的药代动力学。方法: 以新藤黄酸为内标,建立大鼠血浆中藤黄酸葡萄糖酯的UPLC测定方法。采用该方法测定大鼠单剂量静脉注射2、 4 、8 mg/kg 藤黄酸葡萄糖酯后,不同时间点大鼠血浆中的藤黄酸葡萄糖酯的浓度,对其血药浓度-时间采用DAS 2.1 软件拟合,计算药动学参数。结果: 血浆中藤黄酸葡萄糖酯在 0.05～14.0 mg/L 浓度范围内线性关系良好(r=0.9999) ,定量下限为 0.05 mg/L,提取回收率均大于87%,其日内日间RSD均小于10% ,藤黄酸葡萄糖酯按2、4和 8 mg/kg 静脉给药后,在大鼠体内的t_1/2分别为(16.66±1.56)、(16.81±2.21) 和(17.88±2.05) min,AUC_0-t 分别为(12.92±13.14)、(37.3±18.58) 和 (68.22±20.91) min·mg·L^-1。结论: 所建立的UPLC方法操作简便、快速、专属性强,能满足藤黄酸葡萄糖酯在大鼠体内的药代动力学研究。     

酸性磷酸酶在大鼠脉络丛上皮细胞内的亚细胞定位

研究大鼠脑室脉络丛上皮细胞内酸性磷酸酶(Acid phosphatase,AcPase)的超微结构分布.取成年SD大鼠侧脑室、第三脑室和第四脑室的脉络丛组织,按硝酸铅法进行酸性磷酸酶电镜酶细胞化学染色显示.透射电镜下ACPase阳性反应物仅见于脉络丛上皮细胞内的初级和次级溶酶体上.通过延长孵育时间和改变固定条件(戊二醛浓度为0.5%)在脉络丛上皮细胞内的高尔基复合体扁囊和囊泡中也观察到了ACPase阳性反应物.各脑室脉络丛上皮细胞酸性磷酸酶的分布未见明显差异.文中讨论了脉络丛上皮细胞内ACPase的分布特征及其功能.     

固体燃料超燃冲压发动机燃烧室的数值仿真

基于一种固体燃料超燃冲压实验发动机的实验数据,使用数值模拟软件分别对超燃冲压发动机燃烧室的初始状态以及启动后的燃烧流动进行数值模拟。采用用户自定义函数方式给定PMMA燃料进口边界。数值模拟结果显示:燃烧室流场特性分布符合理论分析;燃烧室固体燃料壁面的燃料退移速率与实验数据有一定差异,但是整个燃面沿轴向的燃速分布规律与实验值近似;沿轴向的燃面附近的压力分布与实验结果较为吻合。研究结果表明:该数值计算模型较为合理,对固体燃料超燃冲压发动机的理论研究具有一定参考价值。     

Hippocampal and Reticulo-Thalamic Parvalbumin Interneurons and Synaptic Re-Organization during Sleep Disorders in the Rat Models of Parkinson’s Disease Neuropathology

We investigated the alterations of hippocampal and reticulo-thalamic (RT) GABAergic parvalbumin (PV) interneurons and their synaptic re-organizations underlying the prodromal local sleep disorders in the distinct rat models of Parkinson’s disease (PD). We demonstrated for the first time that REM sleep is a predisposing state for the high-voltage sleep spindles (HVS) induction in all experimental models of PD, particularly during hippocampal REM sleep in the hemiparkinsonian models. There were the opposite underlying alterations of the hippocampal and RT GABAergic PV+ interneurons along with the distinct MAP2 and PSD-95 expressions. Whereas the PD cholinopathy enhanced the number of PV+ interneurons and suppressed the MAP2/PSD-95 expression, the hemiparkinsonism with PD cholinopathy reduced the number of PV+ interneurons and enhanced the MAP2/PSD-95 expression in the hippocampus. Whereas the PD cholinopathy did not alter PV+ interneurons but partially enhanced MAP2 and suppressed PSD-95 expression remotely in the RT, the hemiparkinsonism with PD cholinopathy reduced the PV+ interneurons, enhanced MAP2, and did not change PSD-95 expression remotely in the RT. Our study demonstrates for the first time an important regulatory role of the hippocampal and RT GABAergic PV+ interneurons and the synaptic protein dynamic alterations in the distinct rat models of PD neuropathology.