特殊毒理在卫生学研究中的应用

特殊毒理是研究环境因子的致癌、致突变和致畸等方面的特殊作用,以及对生物体的生殖毒性。鉴于特殊毒理的日益重要,在卫生学研究中也被广泛地采用,无论是毒性研究、环境因子的生物效应观察和接触某毒物的人群监测,以及制订卫生标准等,都引入了特殊毒理试验。本文仅就特殊毒理试验在卫生学研究中的应用,作一简介。一、安全性评价     

无机铅对睾丸生殖内分泌的毒性

随着男性生殖毒理研究的进展,铅对雄性生殖毒性报道增多。现就国内外有关无机铅及其化合物对睾丸生殖内分泌的毒性及作用机理综述如下。     

环境因素对精子质量影响的研究

目前研究认为，环境因素对精子质量造成一定有害影响。本文综述近几年国内外有关环境因素对精子质量影响的研究报道、进一步开展环境生殖毒理研究提供参考。     

毒理基因组学——在基因表达水平上的环境与健康研究

毒理基因组学是在生物高通量技术手段的应用基础上发展起来的一个新的研究领域 ,主要在基因组水平上研究机体对环境因子的应答反应 ,了解基因 环境交互作用在疾病发生中的作用。本文对毒理基因组学的研究目标、研究内容及其在提高环境卫生水平和预防环境相关疾病中的作用进行综述     

持久性有机污染物的毒性及其机制研究进展

持久性有机污染物(POPs)是一类具有高毒性、蓄积性、亲脂性、半挥发性等性质的物质。大量的研究表明,POPs可以对生物体产生不良的健康效应,而其机制并未完全明确。本文主要介绍一些典型的POPs,如多氯代二苯并对二噁英和多氯代二苯并呋喃、多氯联苯等对神经、生殖、内分泌等系统及器官的毒性作用及其机制,为后续深入研究该类物质的毒性机制提供理论依据。     

短链氯化石蜡环境暴露及毒理学效应研究进展

短链氯化石蜡(SCCPs)是一类新型的持久性有机污染物(POPs),广泛存在于环境中,具有生物富集性和生物毒性,其污染现状及对环境和人体健康的潜在风险备受关注。目前,国内对SCCPs污染的研究集中在分析测定方法、环境分布、环境行为等方面,毒理学效应研究资料较少。笔者对我国SCCPs环境暴露和毒理学效应进行了综述,并对SCCPs毒理学研究进行了展望,旨在揭示我国SCCPs污染现状及毒理学研究进展,为环境管理、毒理学研究和健康风险评价提供参考依据。     

肉苁蓉对生殖功能调节作用的研究进展

中医临床实践证明, 肉苁蓉具有补肾阳、益精血、润肠道的作用, 属滋补中药中的珍品。近年来, 侧重肉苁蓉的补肾阳作用, 对其生殖药理和毒理作用进行了深入研究, 有关的研究成果引起了中医药研究工作者的广泛关注。本文结合药用成分分析, 针对肉苁蓉提取物在调节生殖功能方面的作用进行综述。综合分析认为肉苁蓉提取物对雌、雄性生殖内分泌均有调节作用, 可以改善生殖功能, 为"肉苁蓉补肾阳"的中医经典理论观点提供了现代生命科学依据。     

环境与健康(上)

当前,环境与生殖的问题,已是人们研究的热点,因为这是关系到几代人乃至未来民族素质,甚至整个人类前景的重大问题。世界卫生组织人类生殖研究、发展与培训特别规划处与有关国家和研究所在1991年联合举办了一次《环境对生殖健康影响》的国际会议,主要就环境对生殖健康影响和不同环境对人类生殖健康的潜在危害等作了学术研讨。现将此次会议的主要内容及近四年有关环境与生殖的研究综述如下。 环境与生殖的关系可以概括为社会心理因素、生活习惯、营养与食品、药物、职业因素及生物因素对生殖功能的影响。     

第一部分 铅对女工生殖、妊娠及后代健康危害的研究——铅对女工生殖、妊娠及后代健康危害的研究(内容提要)

本研究自J988～1992年四年间,通过设计严谨、周密的流行病学调查和毒理学研究(遗传毒理、生殖毒理等);以及铅对孕鼠脑垂体一卵巢—胎盘轴及人绒毛毒性作用的研究;首次针对国内外急待解决的问题,就铅对女工生殖、妊     

肿瘤坏死因子α与女性生殖

对近年来肿瘤坏死因子（ＴＮＦ－ａ）与女性生殖的研究进展进行综合分析。发现ＴＮＦ－ａ与女性生殖的多个环节有联系,如生殖内分泌、不孕及感染。结论：ＴＮＦ在女性生殖中的作用,对诊治与生殖有关疾病有重要意义。     

孕期持续性有机污染物暴露对妊娠结局和婴幼儿生长发育的影响

环境改变和污染所引起下一代的变化是深刻的,其中胎儿则是最敏感的人群之一。持续性有机污染物(POPs)是环境中很重要的一类化学污染物,随着气候变化和经济快速发展使得其暴露水平和模式也发生改变~([1])。虽然许多POPs在多年前已被淘汰,但由于它们具有持久性、亲脂性、生物累积性、半挥发性和高毒性,在环境中仍有残留。目前国内外动物实验和人群流行病学调查研究显示,孕期暴露POPs可能会对妊娠结局及儿童生长发育产生不良影响。其中包括低出生体质量、早产、出生缺陷、儿童神经系统和生殖系统发育不良等,本文以人群流行病调查资料为基础对孕期暴露POPs对下一代产生的上述影响进行阐述。     

Persistent organic pollutants in food supplies

Persistent organic pollutants (POPs) in various food supplies have important health impacts, but are not as devastating as malnutrition and, perhaps, obesity. POPs should be controlled and the Stockholm Convention is having an accelerating effect on the global decline of POP manufacture and use. Reservoirs from previous misuses are much larger than current manufacture and efforts should be directed at containing these reservoirs, tackling food shortages, and continuing to educate toward following advisories and maintaining a varied diet and food sources.     

A retrospective study of PBDEs and PCBs in human milk from the Faroe Islands

Background  

Persistent organic pollutants (POPs) in wildlife and humans remain a cause of global concern, both in regard to traditional POPs, such as the polychlorinated biphenyls (PCBs), and emerging POPs, such as the polybrominated diphenyl ethers (PBDEs). To determine the time related concentrations, we analyzed human milk for these substances at three time points between 1987 and 1999. Polychlorobiphenylols (OH-PCBs), the dominating class of PCB metabolites, some of which are known to be strongly retained in human blood, were also included in the assessment.     

Individual and Combined Toxicities of Benzo[a]pyrene and 2,2′,4,4′-Tetrabromodiphenyl Ether on Early Life Stages of the Pacific Oyster, <Emphasis Type="Italic">Crassostrea gigas</Emphasis>

Persistent organic pollutants (POPs) are ubiquitous and coexisted in the aquatic environment. Individual and combined toxic effects of benzo[a]pyrene (BaP) and 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on embryogenesis, and larval survival of the Pacific oyster were investigated. The EC₅₀ values of BaP, BDE-47 and their mixture on embryogenesis were 18.4, 203.3 and 72.0 µg/L respectively, while the LC₅₀ values for 96 h larval mortality were 26.8, 244.5 and 108.9 µg/L respectively. The Marking-Dawson additive toxicity indices were ?0.02 and ?0.19, indicating an additive effect with a trend to antagonism. In addition, DNA strand breaks were also observed in oyster embryos after exposure. Our study suggests that BaP and BDE-47 exposure can cause developmental abnormalities, DNA damage and larval mortality. Furthermore, the toxicity of the mixture is slightly lower than individual pollutant. These data will be helpful to predict the toxicity of organic pollutants, and provide criteria for marine water quality standards.     

Behavioural sensitivity of a key Southern Ocean species (Antarctic krill, Euphausia superba) to p,p'-DDE exposure

Persistent organic pollutants (POPs) have been frequently measured throughout the Southern Ocean food web for which little information is available to assess the potential risks of POP exposure. The current study evaluated the toxicological sensitivity of a key Southern Ocean species, Antarctic krill, to aqueous exposure of p,p'-dichlorodiphenyl dichloroethylene (p,p'-DDE). Behavioural endpoints were used as indicators of sublethal toxicity. Immediate behavioural responses (partial immobility and tail flicking) most likely reflect neurotoxicity, while the p,p'-DDE body residue causing a median level of sublethal toxicity in Antarctic krill following 96h exposure (IEC50(sublethal toxicity)=3.9±0.21mmol/kg lipid weight) is comparable to those known to cause sublethal narcosis in temperate aquatic species. Critical body residues (CBRs) were more reproducible across tests than effective seawater concentrations. These findings support the concept of the CBR approach, that effective tissue residues are comparable across species and geographical ranges despite differences in environmental factors.     

Most unwanted.

Persistent organic pollutants (POPs) can travel thousands of miles, accumulate in the food chain, and persist in the environment, taking as long as centuries to degrade. POPs are known to play a role in birth defects, cancer, immune system dysfunction, and reproductive problems in wildlife. While the effects of POPs on human health are unclear, many researchers believe that long-term exposure contributes to increasing rates of birth defects, fertility problems, greater susceptibility to disease, diminished intelligence, and certain cancers. Twelve POPs have been identified by the United Nations Environment Programme as requiring urgent regulatory attention. They include the pesticides aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex, and toxaphene. Of the remaining three POPs, polychlorinated biphenyls are industrial products (used in electrical transformers), and dioxins and furans are unintentional by-products of industrial processes.     

Persistent toxic chemicals in the US food supply

Persistent organic pollutants (POPs) have spread throughout the global environment to threaten human health and damage ecosystems, with evidence of POPs contamination in wildlife, human blood, and breast milk documented worldwide. Based on data from the US Food and Drug Administration, this article provides a brief overview of POPs residues in common foods in the United States food supply. The analysis focuses on 12 chemical compounds now targeted for an international phase out under the Stockholm Convention on POPs. The available information indicates that POPs residues are present in virtually all categories of foods, including baked goods, fruit, vegetables, meat, poultry, and dairy products. Residues of five or more persistent toxic chemicals in a single food item are not unusual, with the most commonly found POPs being the pesticides DDT (and its metabolites, such as DDE) and dieldrin. Estimated daily doses of dieldrin alone exceed US Environmental Protection Agency and US Agency for Toxic Substances Disease Control reference dose for children. Given the widespread occurrence of POPs in the food supply and the serious health risks associated with even extremely small levels of exposure, prevention of further food contamination must be a national health policy priority in every country. Implementation of the Stockholm Convention will prevent further accumulation of persistent toxic chemicals in food. Early ratification and rapid implementation of this treaty should be an urgent priority for all governments.     

Geographical variation of persistent organic pollutants in eggs of threatened loggerhead sea turtles (Caretta caretta) from southeastern United States

Persistent organic pollutants (POPs) are recognized manmade threats to sea turtle populations, but substantial uncertainty exists surrounding their exposure to contaminants and their sensitivity to toxic effects. This uncertainty creates difficulty for conservation managers to make informed decisions for the recovery of these threatened species. To provide baseline concentrations and spatial comparisons, we measured a large suite of POPs in loggerhead sea turtle (Caretta caretta) egg yolk samples collected from 44 nests in three distinct U.S. locations: North Carolina (NC), eastern Florida (E FL), and western Florida (W FL). The POPs included polychlorinated biphenyls (PCBs), organochlorine pesticides such as dichlorodiphenyltrichloroethanes (DDTs), chlordanes, mirex, dieldin, hexachlorocyclohexanes (HCHs), hexachlorobenzene, and toxaphene congeners, as well as polybrominated diphenyl ether congeners (PBDEs). Persistent organic pollutant concentrations were lowest in W FL, intermediate in E FL, and highest in NC egg samples, with several statistically significant spatial differences. This increasing gradient along the southeast coast around the Florida peninsula to North Carolina was explained partly by the foraging site selection of the nesting females. Data from previous tracking studies show that NC nesting females feed primarily along the U.S. eastern coast, whereas W FL nesting females forage in the Gulf of Mexico and Caribbean Sea. The E FL nesting females forage in areas that overlap these two. The foraging site selection also results in exposure to different patterns of POPs. An unusual PBDE pattern was seen in the NC samples, with nearly equal contributions of PBDE congeners 47, 100, and 154. These findings are important to managers assessing threats among different stocks or subpopulations of this threatened species.     

Toxicological Function of Adipose Tissue: Focus on Persistent Organic Pollutants

Background: Adipose tissue (AT) is involved in several physiological functions, including metabolic regulation, energy storage, and endocrine functions.Objectives: In this review we examined the evidence that an additional function of AT is to modulate persistent organic pollutant (POP) toxicity through several mechanisms.Methods: We reviewed the literature on the interaction of AT with POPs to provide a comprehensive model for this additional function of AT.Discussion: As a storage compartment for lipophilic POPs, AT plays a critical role in the toxicokinetics of a variety of drugs and pollutants, in particular, POPs. By sequestering POPs, AT can protect other organs and tissues from POPs overload. However, this protective function could prove to be a threat in the long run. The accumulation of lipophilic POPs will increase total body burden. These accumulated POPs are slowly released into the bloodstream, and more so during weight loss. Thus, AT constitutes a continual source of internal exposure to POPs. In addition to its buffering function, AT is also a target of POPs and may mediate part of their metabolic effects. This is particularly relevant because many POPs induce obesogenic effects that may lead to quantitative and qualitative alterations of AT. Some POPs also induce a proinflammatory state in AT, which may lead to detrimental metabolic effects.Conclusion: AT appears to play diverse functions both as a modulator and as a target of POPs toxicity.     

Persistent organic pollutants (POPs) as environmental risk factors in remote high-altitude ecosystems

Persistent organic pollutants (POPs), and their transformation products, are the most investigated organic environmental contaminants within the past five decades. Organochlorines have been found in virtually all environmental compartments on the globe. Severe environmental implications have been shown to be associated with the presence of the POP group of contaminants in the environment. However, in the late 1990s, Canadian scientists first pinpointed the implication of POPs for high-altitude environments in a comprehensive way (Blais et al., 1998, Nature 395, 585-588). Under certain meteorological and geographic conditions, high-altitude environments can serve as "cold condensers" for atmospheric POP loadings. Subsequent investigations in high-altitude environments in Asia, Europe, and North and South America have confirmed suspicions that high-altitude mountainous regions have the potential to serve as focus regions for POPs and even for nonpersistent, medium-lived contaminants, such as "currently used pesticides", due to cold condensation and deposition in high altitudes. Although the presence and the altitude-dependent increase of POP levels in mountainous regions are confirmed by many international studies, the ecotoxicological consequences still remain largely unknown. At present, only a few studies have been published describing the biological effects in high-altitude environments due to increased POP exposure. Therefore, in this early stage of the international research effort on the ecotoxicological risk evaluation of persistent contaminants in high-altitude, pristine ecosystems, the present review intends to summarize the current state of research on POPs in high-altitude environments and draw preliminary conclusions on possible consequences of the presence of POPs in mountainous ecosystems based on currently available information from alpine and related Arctic environments.