Dose response

剂量反应
  • 文章类型: Journal Article
    Some viruses cause tumor regression and can be used to treat cancer patients; these viruses are called oncolytic viruses. To assess whether oncolytic viruses from animal origin excreted by patients pose a health risk for livestock, a quantitative risk assessment (QRA) was performed to estimate the risk for the Dutch pig industry after environmental release of Seneca Valley virus (SVV). The QRA assumed SVV excretion in stool by one cancer patient on Day 1 in the Netherlands, discharge of SVV with treated wastewater into the river Meuse, downstream intake of river water for drinking water production, and consumption of this drinking water by pigs. Dose-response curves for SVV infection and clinical disease in pigs were constructed from experimental data. In the worst scenario (four log10 virus reduction by drinking water treatment and a farm with 10,000 pigs), the infection risk is less than 1% with 95% certainty. The risk of clinical disease is almost seven orders of magnitude lower. Risks may increase proportionally with the numbers of treated patients and days of virus excretion. These data indicate that application of wild-type oncolytic animal viruses may infect susceptible livestock. A QRA regarding the use of oncolytic animal virus is, therefore, highly recommended. For this, data on excretion by patients, and dose-response parameters for infection and clinical disease in livestock, should be studied.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    先兆子痫是孕产妇和围产期发病率和死亡率的主要原因。据信先兆子痫易感性与脂质分布的改变和通过脂质过氧化导致内皮功能障碍的异常脂质代谢有关。这项研究的目的是在一项大规模研究中评估母体血脂和载脂蛋白水平与先兆子痫的关系。
    使用来自大型病例对照研究的数据(1366例先兆子痫和1741例正常血压对照),我们使用校正逻辑回归模型评估了8种脂质组分分布与子痫前期风险之间的关联.先兆子痫定义为血压≥140/90mmHg和蛋白尿≥300mg/24h(>1+试纸)。亚组分析为早期(<34周)和晚期(≥37周)先兆子痫,在调整后的多项回归模型中,估计对数转化脂质分数水平增加1个标准差的影响.
    调整潜在的混杂因素后,甘油三酯的浓度,载脂蛋白E(ApoE)和载脂蛋白B和A1之间的关系(ApoB/ApoA1)与子痫前期的相关性最强,特别是对于那些早期发病的病例。
    更高水平的甘油三酯,ApoE和ApoB/ApoA1比率与先兆子痫的风险增加有关。需要进一步的研究来进行因果推断,以确认或反驳血脂在先兆子痫中的病因学作用。
    Pre-eclampsia constitutes a leading cause of maternal and perinatal morbidity and mortality. Pre-eclampsia susceptibility is believed to be associated with altered lipid profiles and abnormal lipid metabolism via lipid peroxidation that leads to endothelial dysfunction. The goal of this study was to evaluate the association of maternal blood lipid and apolipoprotein levels with pre-eclampsia in a large-scale study.
    Using data from a large case-control study (1366 cases of pre-eclampsia and 1741 normotensive controls), the association between the distributions of eight lipid fractions and pre-eclampsia risk was evaluated using adjusted logistic regression models. Pre-eclampsia was defined as blood pressure ≥140/90 mmHg and proteinuria ≥300 mg/24 h (>1 + dipstick). Sub-group analyses were conducted for early (<34 weeks) and late (≥37 weeks) pre-eclampsia, estimating the effect of 1 standard deviation increase in log-transformed lipid fraction levels in adjusted multinomial regression models.
    After adjustment for potential confounders, concentrations of triglycerides, apolipoprotein E (ApoE) and the relationship between apolipoprotein B and A1 (ApoB/ApoA1) showed the strongest associations with pre-eclampsia, particularly for those cases with an early onset.
    Higher levels of triglycerides, ApoE and the ApoB/ApoA1 ratio are associated with an increased risk of pre-eclampsia. Further studies that allow for a causal inference are needed to confirm or refute the aetiological role of blood lipids in pre-eclampsia.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    BACKGROUND: A field-evolved herbicide-resistant weed population can represent a heterogeneous composite of subpopulations that differ in their susceptibility and responsiveness to herbicide hormesis. Variable hormesis responsiveness can result in selection for and against certain subpopulations under low herbicide doses, and this has the potential to contribute to the evolution of resistance. The relevance of this hypothesis at practical field rates was studied for two field-collected acetyl-coenzyme A carboxylase (ACCase) target-site resistant (TSR) biotypes of Alopecurus myosuroides Huds. (haplotype Leu1781) exposed to three ACCase inhibitors. Herbicide dose responses were evaluated at the population level and at different subpopulation levels after the dissection of individual plants by herbicide selection and genotyping.
    RESULTS: The practical field rates of fenoxaprop-P were lower than the observed hormetic doses in the resistant subpopulation, whereas the field rates of clodinafop and cycloxydim stimulated the shoot biomass in different resistant subpopulations by 21-38% above that of the control. Because variable dose levels induced hormesis in the different subpopulations, the practical field rates showed a significant potential to selectively enhance parts of a resistant field population, but did not impact or adversely affect other parts of the population.
    CONCLUSIONS: As a consequence of population heterogeneity, herbicide hormesis may impact resistance evolution in weeds at realistic use rates via the selective promotion of individual genotypes. However, the practical relevance of this phenomenon may be influenced by many factors, such as the herbicidal active ingredient used, as indicated in this study. © 2018 Society of Chemical Industry.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    工程纳米材料(ENM)在水介质中的独特行为和颗粒沉降的动态变化,团聚和溶解速率是对一致性的挑战,标准水生危害生物测定结果的可靠性和解释。而毒理学终点(例如,生存,增长,繁殖,等。)在生态毒性生物测定中,主要适用于ENM,溶解物质的标准方法被动态沉降所混淆,生物测定过程中颗粒ENM的聚集和溶解。设计了一个测试框架,以作为确定持续进行水生危害测试的方法的起点,这些方法说明了ENM在测试介质中的行为以及支持代表性暴露计量学的适当数据收集。通过进行三个案例研究来测试具有功能上不同特征和行为的ENM,从而证明了该框架。对颗粒浓度进行时间采样的预测试,在测试介质中对每个ENM进行团聚和溶解。结果表明,银纳米粒子(AgNP)粉末是不可分散的,纳米TiO2粉末是可分散的,但不稳定,和聚乙烯吡咯烷酮涂覆的AgNP在测试介质中相对稳定。基于这些功能结果,进行了Ceriodaphniadubia生物测定,以比较不同的暴露汇总方法(标称,算术平均,几何平均,时间加权平均值)用于计算和表达毒性终点。结果表明,虽然算术平均值对表达更稳定材料的毒性有效,时间加权平均浓度适用于不稳定的纳米TiO2。
    The unique behavior of engineered nanomaterials (ENM) in aqueous media and dynamic changes in particle settling, agglomeration and dissolution rates is a challenge to the consistency, reliability and interpretation of standard aquatic hazard bioassay results. While the toxicological endpoints (e.g., survival, growth, reproduction, etc.) in ecotoxicity bioassays are largely applicable to ENMs, the standard methods as written for dissolved substances are confounded by the dynamic settling, agglomeration and dissolution of particulate ENMs during the bioassay. A testing framework was designed to serve as a starting point to identify approaches for the consistent conduct of aquatic hazard tests that account for the behavior of ENMs in test media and suitable data collection to support representative exposure metrology. The framework was demonstrated by conducting three case studies testing ENMs with functionally distinct characteristics and behaviors. Pretests with a temporal sampling of particle concentration, agglomeration and dissolution were conducted on each ENM in test media. Results indicated that a silver nanoparticle (AgNP) powder was not dispersible, a nano-TiO2 powder was dispersible but unstable, and a polyvinylpyrrolidinone-coated AgNP was relatively stable in test media. Based on these functional results, Ceriodaphnia dubia bioassays were conducted to compare different exposure summary methods (nominal, arithmetic average, geometric average, time-weighted average) for calculating and expressing toxicity endpoints. Results indicated that while arithmetic means were effective for expressing the toxicity of more stable materials, time-weighted averaged concentrations were appropriate for the unstable nano-TiO2.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

公众号