环境激素对人类健康的危害及其作用机制

环境激素是环境中的激素类似物,它在人体和动物体内发挥着类似于激素的作用,通常称为＂外因性内分泌干扰物质＂,干扰体内正常激素的作用.该文介绍激素与环境激素的区别、环境激素的特性、种类;重点阐述环境激素的及其内分泌干扰机制;从环境激素对人类的健康,尤其是对生殖健康的危害,提出了防治环境激素污染的措施.     

环境激素邻苯二甲酸丁基苄酯对家蚕生殖的影响

为了探讨环境激素邻苯二甲酸丁基苄酯(Butyl Benzyl Phthalate,BBP)对家蚕(Bombyx mori)等鳞翅目昆虫的生殖损伤,家蚕饲以不同浓度BBP喷洒后的桑叶,调查了BBP对家蚕造卵、产卵等生殖机能的影响。结果表明:BBP影响家蚕的体重增加、存活率及产卵特性,随着BBP浓度的增加,影响逐渐加大,1.6 mmol/L添食5龄起蚕时,造卵数及产卵数仅为对照的56.1%和51.4%,对受精及孵化等的影响具有相同变化趋势,只是对雄性的影响大于雌性;不同时期的添食结果表明,BBP对家蚕生殖的影响:3龄起蚕4龄起蚕5龄起蚕,0.16 mmol/L添食时,造卵数及产卵数分别只有对照区的57.5%、66.3%、97.6%及58.7%、74.1%、96.0%;BBP添食对存活下来的个体的下一代的茧质几乎没有影响。由以上结果表明:BBP对家蚕的生殖具有明显的毒害作用,BBP添食浓度越高,接触时间越早,在蚕体内积累越多,产生的生殖毒性就越大,而且这种毒性雄性大于雌性。     

苯污染对人类健康影响研究进展

近年来,随着人民生活水平的不断提高, 一些消费者, 在购房、装修、添置家具的过程中,因缺乏相关的预防知识,造成室内空气中苯污染,严重者危害着家人的身心健康, 甚至造成了难以挽回的悲剧。室内环境中的苯污染主要来自含苯的胶黏剂、油漆、涂料和防水材料的溶剂或稀释剂。苯可经呼吸道、皮肤、消化道吸收进入机体,引起人体急、慢性中毒。轻度慢性苯中毒者出现头晕、头痛、恶心胸闷、乏力、失眠或多梦、性格改变、记忆力减退等; 重度慢性苯中毒引起多发性神经病、脊髓炎、球后视神经炎、癫痫及精神失常, 造成血液系统和神经系统难以挽回的健康危害,甚至因呼吸循环衰竭而死亡。育龄妇女长期吸入苯会导致月经失调, 孕期的妇女妊娠并发症的发病率会显著增高, 甚至会导致流产或胎儿先天缺陷。国际卫生组织已经把苯定为强烈致癌物质, 苯可以引起白血病和再生障碍性贫血也被医学界公认。通过对苯的成分结构和苯的生殖遗传毒性、神经毒性、血液免疫毒性、致癌作用及其对人类健康影响的阐述, 为研究预防控制苯污染对人类健康的影响提供参考依据。     

典型环境激素壬基酚对水产品安全性的影响

环境激素类物质由于其具有生态毒性、难降解与生物累积性,对水产品的危害越来越受到人们的重视。典型环境激素壬基酚(NP)是壬基酚聚氧乙烯醚（NPE）的降解产物,后者作为非离子表面活性剂,与人们的日常生活关系密切,但同时也对水产生物及人类健康产生了危害。该文综述了壬基酚的环境激素特征及污染途径,在水环境中的分布,对水产生物的生理生态影响以及其通过生物富集和传递效应对人类健康形成的潜在威胁,可作为中国水产品安全风险预警体系的参考资料,为壬基酚对人体健康的风险评估提供依据。     

环境激素对动物生存的威胁

日前,一份"尽快立项开展我国有毒化学品污染及环境安全问题研究"的建议书被送到朱镕基总理手中,魏复盛院士、徐晓白院士等19位学者就化学制剂对中国环境安全造成的威胁提出了警告,其中环境激素的污染问题成为最重要的内容之一.无论是人类还是动物,几乎都生活在"环境激素的海洋"之中,环境激素污染问题已同温室效应、臭氧层破坏等问题一样,严惩威胁着全球环境和人类健康.     

环境激素DBP对拟南芥体外培养叶片超微结构的影响

报道了酞酸酯类化合物DBP对拟南芥离体培养叶片超微结构的影响。在DBP(1.0mg·L-1)处理第3天即观察到拟南芥叶片叶绿体的超微结构受到破坏。不同浓度的DBP长期处理植株(40d)出现叶片白化、节间短缩等异常现象。在0.01mg·L-1DBP处理40d植株的叶细胞中,叶绿体出现解体,破碎部分呈颗粒状,散落其间,但细胞结构完整;0.1mg·L-1DBP处理后引起叶绿体的进一步解体,叶绿体中类囊体基粒和片层结构解体,细胞出现空洞现象,其它细胞器很少观察到;1.0mg·L-1DBP和2.0mg·L-1DBP处理植株叶片叶绿体中类囊体基粒和片层结构破碎,叶绿体结构也解体,细胞中其它细胞器数目极少。     

宠物与人类健康

本文围绕宠物与人类健康主题,阐述了宠物对人类健康的积极作用;宠物对人类健康的负面影响,并对保障我国宠物业健康发展提出建议。     

犬猫对人类健康的危害

就犬、猫传播给人的几种常见的人畜共患病,从传染源、传播途径及预防措施等方面进行了综合论述。     

Role of thyroid hormones in human and laboratory animal reproductive health

The highly conserved nature of the thyroid gland and the thyroid system among mammalian species suggests it is critical to species survival. Studies show the thyroid system plays a critical role in the development of several organ systems, including the reproductive tract. Despite its highly conserved nature, the thyroid system can have widely different effects on reproduction and reproductive tract development in different species. The present review focuses on assessing the role of thyroid hormones in human reproduction and reproductive tract development and comparing it to the role of thyroid hormones in laboratory animal reproduction and reproductive tract development. The review also assesses the effects of thyroid dysfunction on reproductive tract development and function in humans and laboratory animals. Consideration of such information is important in designing, conducting, and interpreting studies to assess the potential effects of thyroid toxicants on reproduction and development.     

Genetically modified crops: environmental and human health concerns

About 10,000 years ago subsistence farmers started to domesticate plants and it was only much later, after the discovery of the fundaments of genetics, those organisms were submitted to rational genetic improvement mainly by selecting of traits of interest. Breeders used appropriate gene combinations to produce new animal races, plant varieties and hybrids, as well as improved microorganisms such as yeasts. After the introduction of recombinant DNA techniques, the transfer of DNA between species belonging to different genera, families or kingdoms became possible. The release of transgenic plants has aroused debates about several aspects of the environmental and human risks that could result from the introduction of genetically modified crops. Less effort has been dedicated to evaluate the impact of transgenic plants on their associated microorganisms, some of which (e.g. nitrogen-fixing bacteria, mycorrhizal fungi and endophytic microbiota) are extremely important for the survival of the plant. Investigations have been made regarding the horizontal transfer of genetic material between transgenic plants and microorganisms and on the disturbance of useful symbiotic associations between plants and endophytic, epiphytic and rhizosphere communities. In most cases the results do no show any adverse effect of transgenic plants on autochthonous plant-associated microorganisms. Results from our laboratory show small changes caused by genetically modified endophytic bacteria on the indigenous endophytic population of the sweet orange Citrus sinensis. In tests using appropriated fungal strains preliminary results using extracts from transgenic plants indicate that these plants do not affect haploidization, mitotic crossing-over, mutation rate or chromosomal alterations.     

International programme on chemical safety (IPCS) environmental health criteria on boron human health risk assessment

The International Program on Chemical Safety (IPCS), a collaborative program of the United Nations Environment Program, the International Labour Organization (ILO), and the World Health Organization (WHO), includes the Environmental Health Criteria (EHC) Program inaugurated in 1973 by WHO. These EHC are integrated evaluations of the human health and environmental risks from exposure to specific chemicals carried out by a group of international scientists. Boron (B) was evaluated at an IPCS Task Group (TG) convened in November 1996. All TGs are convened under WHO rules and procedures. These procedures relate the overall process used to prepare an EHC including transparency of the process, conflict of interest, the roles of Members and Observers, and the conduct of the TG. The scope and purpose of an EHC, for an element such as B, and its possible role in national and international chemical safety programs will be discussed. In the early 1990s, countries asked that IPCS request TGs to prepare, where data permit, health-based guidance values (GVs) (both total daily intake and to recommend health-based guidelines for various environmental media). This final evaluation in an EHC reflects the collective consensus view of the TG Members. To foster the use of consistent methodology by TGs, IPCS prepared in 1994 an EHC on the methodology for the preparation of GVs for human exposure limits (EHC 170). In developing their final evaluation, TGs have been asked to consider using this methodology. This was done by the TG on B, and a total daily intake for humans of 0.4 mg/kg body wt was derived from animal studies of reproductive and developmental effects in rodents and pharmacokinetic data from both animals and humans. The application of the methodology described in EHC 170 regarding choice of critical effect and uncertainty factors will be discussed.     

Influences of gender and sex hormones on hypoxic ventilatory response in cats.

Hypoxic ventilatory response (HVR) is known to be increased by female as well as male sex hormones, but whether there are differences in HVR between men and women remains unclear. To determine whether gender differences exist in HVR, we undertook systematic comparisons of resting ventilation and HVR in awake male and female cats. Furthermore to explore the potential contribution of sex hormones to gender differences observed, we compared neutered and intact cats of both sexes. Resting ventilation differed among the four groups, but differences disappeared with correction for body weight. Intact females had a lower end-tidal PCO2 than intact male cats (females: 31.6 +/- 0.4 Torr vs. males: 33.6 +/- 0.4 Torr, P less than 0.05), indicating an increased alveolar ventilation per unit CO2 production. HVR expressed as the shape parameter A was similar among the four groups of animals. However, baseline (hyperoxic; end-tidal PO2 greater than 200 Torr) minute ventilation [VI(PO2 greater than 200)] differed among the groups. Therefore we normalized HVR by dividing the shape parameter A by VI(PO2 greater than 200) to compare the relative hypoxic chemosensitivity among the various groups of animals. In addition, we further normalized HVR for body weight, because body size influences ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coastal wetland management in Florida: environmental concerns and human health

High mosquito populations have always been a part of Florida??s environment. While mosquito-transmitted diseases have played a major role in Florida??s history, saltmarsh mosquitoes have not been implicated in these disease outbreaks. However, the impact of high saltmarsh mosquito numbers on the well-being of residents and visitors cannot be underestimated. Coastal wetland management efforts in Florida, which date back to the 1920s, have included ditching, dredging and filling, and impounding, all having mosquito control and environmental benefits and liabilities. In the early 1980s, efforts to encourage coastal wetlands management for both mosquito control and environmental interests came to the forefront. This resulted in the Florida Legislature creating the Florida Coordinating Council on Mosquito Control and its Subcommittee on Managed Marshes. Through the efforts of these committees, a heavy investment in research, interagency cooperation, and public acquisition of coastal wetlands property, tremendous progress has been made in management of coastal wetlands. This has occurred largely by implementing management and restoration techniques that minimize environmental impacts, allow for mosquito control, and minimize the need for pesticide use. Continued efforts are needed to place into public ownership remaining privately owned coastal wetland property to allow implementation of best management practices on these important habitats.     

Effects of environmental change on wildlife health

Environmental change has negatively affected most biological systems on our planet and is becoming of increasing concern for the well-being and survival of many species. At an organism level, effects encompass not only endocrine disruptions, sex-ratio changes and decreased reproductive parameters, but also include teratogenic and genotoxic effects, immunosuppression and other immune-system impairments that can lead directly to disease or increase the risk of acquiring disease. Living organisms will strive to maintain health by recognizing and resolving abnormal situations, such as the presence of invading microorganisms or harmful peptides, abnormal cell replication and deleterious mutations. However, fast-paced environmental changes may pose additional pressure on immunocompetence and health maintenance, which may seriously impact population viability and persistence. Here, we outline the importance of a functional immune system for survival and examine the effects that exposure to a rapidly changing environment might exert on immunocompetence. We then address the various levels at which anthropogenic environmental change might affect wildlife health and identify potential deficits in reproductive parameters that might arise owing to new immune challenges in the context of a rapidly changing environment. Throughout the paper, a series of examples and case studies are used to illustrate the impact of environmental change on wildlife health.