Occupational chronic exposure to metals

Summary Stainless steel welders (n = 103) were examined. To estimate external exposure, personal air sampling was used. Internal exposure was quantified by the determination of nickel levels in erythrocytes, plasma and urine. Men and women (n = 123) were examined for control purposes. In the plasma and erythrocytes of the controls the nickel concentration was below the level of detection (< 1.81 μg/l). The element concentrations in urine were between < 0.1 and 13.3 μg/l. Of the controls 95% showed nickel levels in urine below 2.2 μg/l (reference value). The average concentration of nickel in the air was 93 ± 81 μg/m³. The average concentration of nickel in the plasma samples was 4.9 ± 4.0 μg/l (95th percentile 12.8 μg/L). In erythrocytes nickel could not be detected. The nickel concentrations in the urine of the welders were 18.5 ± 28.5 μg/l on average (95th percentile 52.5 μg/l). Only a weak correlation between the nickel levels of plasma and urine could be detected (C_urine = 2.07 + 8.45 C_plasma; r = 0.294; p < 0.01). Based on our results and on the reported literature a future limit value for the nickel concentration in urine should lay between 30 and 50 μg/l. This value corresponds to an external exposure of 500 μg nickel per cubic metre.     

无干扰法检查纯水中重金属

目的:科学地控制纯化水中重金属的限度。方法:采用精制处理后的检查专用试验水,按《中国药典》方法检查纯化水中的 重金属。结果:精制处理后的检查专用试验水用于检查纯化水中的重金属可排除干扰。结论:精制处理后的检查专用试验水中的重 金属含量限定在极微量范围内,可极大地减少干扰,使检查结果更加准确。     

硫酸鱼精蛋白注射液细菌内毒素检查法标准研究

目的:建立硫酸鱼精蛋白注射液细菌内毒素的检查方法.方法:按<中国药典>2000年版二部附录ⅪE、ⅪX F进行实验和结果判断.结果:用三个不同生产厂家,不同标示灵敏度鲎试剂进行研究,硫酸鱼精蛋白注射液最大不干扰浓度为0.042mg/ml,并对两个生产厂家的6批样品进行检查,均无干扰作用,其细菌内毒素量均小于6EU/mg.结论:本品可以用细菌内毒素检查法(凝胶法)代替热原检查法控制细菌内毒素的含量,硫酸鱼精蛋白注射液的细菌内毒素理论限值为6EU/mg.     

Potential health risks to adults and children in the UK from exposure to dietary lead in gamebirds shot with lead ammunition

We estimate potential risks to human health in the UK from dietary exposure to lead from wild gamebirds killed by shooting. The main source of exposure to lead in Europe is now dietary. We used data on lead concentrations in UK gamebirds, from which gunshot had been removed following cooking to simulate human exposure to lead. We used UK food consumption and lead concentration data to evaluate the number of gamebird meals consumed weekly that would be expected, based upon published studies, to result in changes, over and above those resulting from exposure to lead in the base diet, in intelligence quotient (IQ), Systolic Blood Pressure and chronic kidney disease (CKD) considered in a recent opinion of the European Food Safety Authority (EFSA) to be significant at a population level and also in SAT test scores and in rates of spontaneous abortion. We found the consumption of <1 meal of game a week may be associated with a one point reduction in IQ in children and 1.2–6.5 gamebird meals per week may be associated with the other effects. These results should help to inform the development of appropriate responses to the risks from ingesting lead from ammunition in game in the UK and European Union (EU).     

Self-organizing maps based on limit cycle attractors

Recent efforts to develop large-scale brain and neurocognitive architectures have paid relatively little attention to the use of self-organizing maps (SOMs). Part of the reason for this is that most conventional SOMs use a static encoding representation: each input pattern or sequence is effectively represented as a fixed point activation pattern in the map layer, something that is inconsistent with the rhythmic oscillatory activity observed in the brain. Here we develop and study an alternative encoding scheme that instead uses sparsely-coded limit cycles to represent external input patterns/sequences. We establish conditions under which learned limit cycle representations arise reliably and dominate the dynamics in a SOM. These limit cycles tend to be relatively unique for different inputs, robust to perturbations, and fairly insensitive to timing. In spite of the continually changing activity in the map layer when a limit cycle representation is used, map formation continues to occur reliably. In a two-SOM architecture where each SOM represents a different sensory modality, we also show that after learning, limit cycles in one SOM can correctly evoke corresponding limit cycles in the other, and thus there is the potential for multi-SOM systems using limit cycles to work effectively as hetero-associative memories. While the results presented here are only first steps, they establish the viability of SOM models based on limit cycle activity patterns, and suggest that such models merit further study.     

对中国药典2015年版硫酸庆大霉素原料及其注射液标准中存在问题的探讨

中国药典2015年版中对硫酸庆大霉素原料和注射液标准进行了修订,其中在有关物质检查项下二者的限度数值相同。但由于原料和注射液中硫酸庆大霉素有关物质含量的含义和量纲(单位)不同,使得可能出现合格原料生产出不合格注射液的尴尬局面。本文从庆大霉素含量表征的特点入手,通过阐述原料和其制剂有关物质含量表述方式和量纲(单位)方面的差异,并以量效统一化研究为基础,讨论可以确保两标准限度间相互匹配的解决方案,从而为该品种的合理修订提供理论支撑。     

国内外中草药吡咯里西啶类生物碱控制情况浅析

吡咯里西啶生物碱(PAs)是一类分布广泛的植物性毒素,具有1,2位双键结构和7、9位酯基取代的PAs具有较强肝毒性(HPAs),其在国内外食品、中草药中的控制得到广泛关注。本文重点阐述蜂蜜、茶产品、中草药等不同产品中PAs前处理方法、检测方法以及相关控制要求,为多种中药材和其他产品中PAs的检测和控制提供参考依据。     

氯霉素水杨酸搽剂微生物限度检查方法的验证

目的建立氯霉素水杨酸搽剂的微生物限度检查方法。方法参照《中国药典》2010版,采用5种阳性对照菌回收率试验测定其是否含抑菌成分。结果该品种对大肠埃希菌、枯草芽孢杆菌、金黄色葡萄球菌、白色念珠菌和黑曲霉均没有抑菌活性,细菌、霉菌和酵母菌数及控制茵的检查采用常规法进行。结论用该方法进行微生物限度检查可以客观地反映药物中微生物的污染状况,可用于该制剂微生物控制。     

高传能线密度辐射对人眼晶状体的危害

眼晶状体是人体对辐射最敏感的组织之一,电离辐射的生物效应因其传能线密度(linear energy transfer,LET)的不同而不同,同等吸收剂量条件下,高LET辐射生物效应比低LET辐射更强,尽管目前辐射对眼晶状体的影响这一领域已经有了较多研究,但对于高LET对眼晶状体的影响知之甚少.本文简述人眼晶状体剂量限值...     

A Multiple Imputation Approach for Estimating Rank Correlation With Left-Censored Data

Frequently the correlation between two different measures of viral load obtained from each of a sample of patients is assessed in HIV studies. Kendall’s tau and Spearman’s rank correlations are often used for this assessment instead of Pearson’s correlation coefficient as they are not affected by outliers and nonnormality. However, such viral load data may be subject to left censoring due to values below assay detection limits. In this situation the usual estimators for the rank correlations (based on assigning ties to the values below the detection limits) may be severely biased. We propose a multiple imputation approach using a truncated bivariate normal model for imputation. Simulation results indicate that the imputation estimates are apparently unbiased for bivariate normally distributed data and still perform well if the data are misspecified.