双酚A对生殖系统的影响及其作用机制

双酚A(Bisphenol A,BPA)是酚类环境雌激素中的一种,人群暴露剂量的BPA会对机体产生一定的影响,主要包括生殖系统、胚胎发育、中枢神经系统、肿瘤的发生等。而对生殖系统的研究尤为广泛,BPA可引起雄性哺乳动物性腺发育不良、精子数量减少等,引起雌性哺乳动物阴道、子宫、卵巢等形态及功能上的改变。BPA对生殖系统影响的机制多样化,可能通过以下几个途径发挥作用:雌激素核受体及膜受体、雌激素相关受体、下丘脑-垂体-性腺轴等。综述双酚A对生殖系统的影响及其可能的作用机制。     

双酚A与健康的关系

双酚A（BPA）作为一种环境雌激素,广泛应用于日常生活的各个领域,而且其可通过多种途径（主要食物）进入人体。因此双酚A对人类健康的影响逐渐引起广泛关注和重视。目前,双酚A对生殖系统的研究较为广泛,过量暴露双酚A可引起雄性哺乳动物性腺发育不良,也会对雌性哺乳动物的卵巢和乳腺等造成严重危害;最近一些新的研究发现双酚A对脑及行为的发育也有很大影响;双酚A对心血管疾病,2型糖尿病及肥胖等疾病的影响也有一些报道。我国对BPA的研究刚刚起步,本文对双酚A的代谢与暴露情况以及对人体健康影响的最新观点和进展进行如下综述。     

双酚A作用机制的研究进展

双酚A(bisphenol A,BPA)是一种化工原料,对人体内分泌有一定干扰作用.研究表明,长期暴露于BPA可能对人体产生不良影响.目前对BPA作用机制的研究主要集中于受体[雌激素受体(ER)、雌激素受体相关受体(ERR)、雄激素受体(AR)、糖皮质激素受体(GR)、甲状腺激素受体(TR)]、基因[同源盒基因(HOXA10、HSP70)]、细胞因子[白细胞介素(IL-4、IL-10)、干扰素γ(IFN-γ)等]和信号通路(Fas/FasL信号通路、线粒体信号通路)对生殖系统的影响等.最近研究发现,BPA可与其他一些物质产生相互作用,如BPA与维生素C联合应用的肾脏氧化损伤,应加强对BPA与其他物质相互作用的研究.     

双酚A对机体的影响及其作用机制

双酚A(Bisphenol A,BPA)广泛存在于塑料制品中,是人们在生产生活中不可避免接触到的一类环境雌激素.研究发现即使低剂量的BPA也会对机体产生一定的影响.BPA对机体的影响是多方面的,主要包括生殖系统、胚胎发育、神经系统、免疫系统、肿瘤发生等.BPA的作用机制多样化,不但可通过内分泌系统影响机体正常激素水平而且可通过不同受体途经产生相应的生物学效应,还与癌症相关.尽管BPA对机体的影响及其可能的作用机制的报道很多,但仍不够完善.本文就BPA对机体的影响做以概述,并探讨分析其可能的作用机制.     

双酚A生殖与发育毒性研究现状

双酚A(bisphenol A,BPA)是一种常见的化工原料,主要用于合成环氧树脂和酚醛树脂,其制品被广泛应用.BPA是一种公认的动物内分泌干扰物,具有雌激素活性及抗雄激素活性,会干扰机体正常的内分泌功能,对生殖系统及子代生长发育造成影响.近年来的研究特别关注低剂量双酚A[＜50mg/(kg· d)]暴露是否会影响生殖系统的生长发育及其功能、大脑发育及行为.美国与欧盟制定的50μg/(kg·d)的参考剂量受到质疑.本文主要集中综述双酚A的整体动物研究及人群调查现状,进而认识双酚A暴露可能引起的不良结局.     

雌激素受体在促进生殖系统癌细胞增殖和转化中的作用

环境内分泌干扰物是一类广泛存在于环境中、进入机体后模拟激素作用干扰内分泌系统导致疾病的外源性物质。近年来,生殖系统雌激素依赖性疾病发病率逐年增加,如乳腺癌、卵巢癌、前列腺癌等。研究表明,环境内分泌干扰物暴露可以增加生殖系统癌症的发生率。本文对多种环境内分泌干扰物[壬基酚（nonylphenol,NP）、辛基酚（octylphenol,OP）、双酚A（bisphenol,BPA）等]通过雌激素受体影响类固醇激素的合成、氧化损伤、影响细胞信号传导等途径刺激肿瘤生长,以及诱导/抑制肿瘤细胞上皮-间充质转化的情况进行了综述。     

双酚A雄性生殖系统毒性的研究进展

双酚A(4,4’-二羟基二苯丙烷,BPA)是人类环境中广泛存在的具有雌激素样效应的内分泌干扰物,其对男性生殖的损害日益引起人们的关注。研究表明BPA对睾丸组织中不同类型的细胞均能产生毒性效应。本文就近年来BPA暴露对雄性生殖系统的研究成果进行综述。建议今后的研究工作中应加强对男性生殖流行病学方面的调查研究,深入探讨BPA的睾丸毒性机制,为暴露人群制定有效的干预策略。     

双酚A对哺乳动物生殖系统影响的研究进展

现代工业中,双酚A(BPA)被广泛应用于聚碳酸酯塑料和环氧树脂的制造,同时其也是一种具有雌激素样作用的化合物.因其被大量使用,已造成人等哺乳动物广泛暴露其中.动物实验结果表明:雌性妊娠期或动物新生期暴露于BPA可诱发后代或动物幼年的性早熟、乳腺组织发育异常、前列腺组织增生及雄性精子生成下降等,最终会导致乳腺组织的癌前病变及生殖道的严重损害.另外,对暴露BPA的人群调查也发现,BPA对生殖系统有明显的毒性作用,其中包括可导致男性性功能障碍等.     

环境雌激素双酚A对男性生殖细胞影响的研究进展

近年来,世界各国男性不育的检出率呈逐年增高趋势.男性不育的原因复杂,包括先天性疾病和后天性因素如外伤、不良生活作息行为（吸烟、酗酒等）、环境污染、药物滥用等.最近研究报道,发育早期暴露环境雌激素可干扰男性生殖系统发育和功能.双酚A（bisphenol A,BPA）是最普遍存在的一种环境雌激素.动物实验和体外研究报道,发育早期暴露BPA可抑制人和小鼠胎儿期睾丸间质细胞分泌睾酮；BPA可通过影响雄性子代生精细胞内基因的正常表达,干扰减数分裂,影响精子的产生；BPA还可降低新生小鼠睾丸支持细胞间连接蛋白的表达；在激素水平上,BPA可抑制小鼠促性腺激素释放激素和卵泡刺激素的产生.本文就BPA通过影响睾丸间质细胞、生精细胞和支持细胞的功能,导致男性不育进行综述,对进一步研究男性不育的原因提供新思路.     

027雌激素和精子发生

迄今为止,人们认为外源性雌激素能引起雄性动物生殖系统发育异常,但作用机制不清楚.近来研究发现,内源性雌激素在精子发生中起重要作用,但如何作用不明确.因此,要全面地认识和评价外源性雌激素和内源性雌激素对精子发生的影响,就有必要对它们影响精子发生的机制进行深入的研究.基于此,本文对近年来这方面的研究进行了综述.本文主要阐述了正常的精子发生过程;从下丘脑-垂体-睾丸轴、睾丸功能、输精管和附睾等几个方面,在细胞和分子水平上阐述了外源性雌激素对雄性生殖系统的影响和可能机制;在细胞和分子水平上,通过雌激素受体基因剔除实验研究和芳香化酶基因剔除实验研究来说明内源性雌激素对雄性生殖系统的影响和可能机制,并比较了剔除雌激素受体α基因、雌激素受体β基因、雌激素αβ基因和芳香化酶基因对雄性生殖系统的影响;最后对雌激素研究的进一步发展提出了展望.     

The human drama of genetics: 'hard' and 'soft' media representations of inherited breast cancer

This paper examines media coverage of 'breast cancer genetics', and explores its implications for public understanding. We present a content analysis of coverage in British newspapers and look at a variety of popular forms, including women's magazines, television soap opera and radio drama. Genetic/inherited risk receives a great deal of coverage across a wide range of media formats and outlets. Much of this attention has focused on individuals from 'high risk families' and dilemmas around prophylactic mastectomies. Through examining media coverage, combined with interviews with media personnel and their sources, we show why this story proved so attractive to the media and highlight the different production values which influence coverage. Finally, we introduce preliminary findings from focus group discussions to demonstrate how such 'human interest' framing has engaged audience attention and influenced public understandings. The paper concludes by highlighting the implications for analysing, predicting, and engaging with, media representations of science.     

Worker education in the primary prevention of occupational dermatoses

This paper reports the evaluation of a skin care education programmeconducted on a fine chemicals manufacturing site where over1,000 employees are located. Approximately 60% are involvedin chemical manufacture. Over a 12 month period production staffreceived training in prevention of occupational dermatoses linkedto a site-wide poster initiative. The incidence of new casesof occupational dermatoses fell from 0.055 (70 cases in 1,277employees) to 0.021 (27 cases in 1,277 employees) before andafter the intervention respectively (p<0.0001). After otherfactors such as chemicals handled, observer bias and changesin reporting related to socioeconomic climate were taken intoaccount it is concluded that this study demonstrates the importanceof worker education as a tool for primary prevention of disease.Training materials such as video and poster presentations maybe effectively used in the chemical manufacturing industry asan adjunct to prevention and control of exposure to substanceshazardous to the skin. Such methods may also be used in otherindustries where there are significant risks of dermatoses.     

Regional Variation in Travel-related Illness acquired in Africa,March 1997–May 2011

To understand geographic variation in travel-related illness acquired in distinct African regions, we used the GeoSentinel Surveillance Network database to analyze records for 16,893 ill travelers returning from Africa over a 14-year period. Travelers to northern Africa most commonly reported gastrointestinal illnesses and dog bites. Febrile illnesses were more common in travelers returning from sub-Saharan countries. Eleven travelers died, 9 of malaria; these deaths occurred mainly among male business travelers to sub-Saharan Africa. The profile of illness varied substantially by region: malaria predominated in travelers returning from Central and Western Africa; schistosomiasis, strongyloidiasis, and dengue from Eastern and Western Africa; and loaisis from Central Africa. There were few reports of vaccine-preventable infections, HIV infection, and tuberculosis. Geographic profiling of illness acquired during travel to Africa guides targeted pretravel advice, expedites diagnosis in ill returning travelers, and may influence destination choices in tourism.     

The design of hazard risk assessment matrices for ranking occupational health risks and their application in mining and minerals processing

Two hazard risk assessment matrices for the ranking of occupational health risks are described. The qualitative matrix uses qualitative measures of probability and consequence to determine risk assessment codes for hazard-disease combinations. A walk-through survey of an underground metalliferous mine and concentrator is used to demonstrate how the qualitative matrix can be applied to determine priorities for the control of occupational health hazards. The semi-quantitative matrix uses attributable risk as a quantitative measure of probability and uses qualitative measures of consequence. A practical application of this matrix is the determination of occupational health priorities using existing epidemiological studies. Calculated attributable risks from epidemiological studies of hazard-disease combinations in mining and minerals processing are used as examples. These historic response data do not reflect the risks associated with current exposures. A method using current exposure data, known exposure-response relationships and the semi-quantitative matrix is proposed for more accurate and current risk rankings.     

Die sogenannte Vinylchlorid-Krankheit—eine berufsbedingte Systemsklerose?

Zusammenfassung Es wurden 13 Arbeiter untersucht, die zwischen 1 3/4 und 18 Jahren in einem PVC-herstellenden Betrieb beschäftigt waren. 8 von ihnen wiesen sklerodermieartige Hautveränderungen (Abb. 2) auf, die histologisch charakterisiert sind durch Verbreiterung und Homogenisierung der kollagenen Faserbündel (Abb. 3 u. 4) sowie Fragmentation und Rarefizierung der elastischen Fasern (Abb. 5). Bei 7 Patienten bestanden trommelschlegelartige Auftreibungen einzelner Fingerendphalangen (Abb. 1). 11 Patienten zeigten Durchblutungsstörungen der Extremitäten (4 von diesen ein Raynaud-Syndrom) und 6 Patienten Acroosteolysen einzelner Fingerendphalangen (Abb. 6, Tabellen 1–3).Darüber hinaus bestand bei allen Patienten eine Thrombocytopenie, bei 12 Patienten eine Splenomegalie, bei 11 Patienten eine Einschränkung der Leberfunktion (erhöhte BSP-Retention). An der Leber ließ sich histologisch bei den 5 laparoskopierten Patienten eine deutliche Fibrosierung der Portalfelder nachweisen. Bei 4 Patienten bestanden Oesophagusvaricen (Tabellen 4 u. 5). 8 Patienten zeigten eine Partialinsuffizienz mit Hinweisen für vorwiegend restriktive Veränderungen.Die hier beschriebenen Veränderungen gehen weit über das bisher bekannte Acroosteolysesyndrom hinaus. Es wird der dringende Verdacht geäußert, daß langfristige Vinylchlorid-Exposition dieses komplexe Krankheitsbild verursacht. Daher wird für diese systemische Krankheit die Bezeichnung Vinylchlorid-Krankheit vorgeschlagen.Wir danken Frau E. Voigtländer für die Herstellung der klinischen und histologischen Abbildungen.     

Psychopathological features of a patient population of targets of workplace bullying

BACKGROUND: A strong association between workplace bullying and subsequent anxiety and depression, indicated by empirical research, suggests that bullying is an aetiological factor for mental health problems. AIMS: To evaluate levels of stress and anxiety-depression disorder developed by targets of workplace bullying together with outcome at 12 months and to characterize this population in terms of psychopathology and sociodemographic features. METHODS: Forty-eight patients (36 women and 12 men) meeting Leymann Inventory of Psychological Terror criteria for bullying were included in a prospective study. Evaluations were performed at first consultation and at 12 months using a standard clinical interview, a visual analogue scale of stress, the Hospital Anxiety and Depression (HAD) scale, the Beech scale of stress in the workplace and a projective test (Picture-Frustration Study). RESULTS: At first consultation, 81% of patients showed high levels of perceived stress at work and 83 and 52% presented with anxiety or depression, respectively. At 12 months, only 19% of working patients expressed a feeling of stress at work. There was a significant change in symptoms of anxiety while there was no change in symptoms of depression. Stress at work and depression influenced significatively capacity to go back to work. At 12-month assessments, workers showed a significantly better score on the HAD scale than non-workers. Over half the targets presented a neuroticism-related predominant personality trait. CONCLUSION: Workplace bullying can have severe mental health repercussions, triggering serious and persistent underlying disorders.     

The rise and fall in incidence of malignant mesothelioma from a British Naval Dockyard, 1979-1999

BACKGROUND: The incidence of malignant mesothelioma in Britain is predicted to rise over the next 15-25 years because of past failure to protect the workforce against inhalation of asbestos. In British Naval dockyards, alternative insulation materials and respiratory protection were introduced from the mid-1960s. Aims This study was carried out to investigate the effects of these control measures on mesothelioma deaths in dockyard workers. METHODS: Cases of mesothelioma of the pleura and peritoneum between 1979 and 1999 in workers from the Devonport Naval Dockyard, south-west England, were sought from coroners' and medico-legal records. RESULTS: Three hundred and one cases were identified, 7% peritoneal. The peak incidence occurred in 1991 with 25 cases per annum (quadratic model fit R(2) = 74.2%, P < 0.001) and we predict that by 2003 the incidence will fall to fewer than five cases per annum. The mean time between first exposure and presentation was 48.5 years [95% confidence interval (CI) = 47.3-49.8], but this was significantly shorter in the more heavily exposed trades, when compared with the less heavily exposed (42 years, 95% CI = 39.0-45.0, versus 49.5 years, 95% CI = 48.2-50.9). Those with higher exposure were also at significantly greater risk of peritoneal disease (P < 0.023, Fisher's exact test). CONCLUSION: The reduction in incidence of mesothelioma is greater than can be accounted for by reduction in numbers of dockyard workers over the last 50 years. Changes in insulation materials and improved industrial hygiene measures introduced into the Devonport Dockyard from the mid-1960s have resulted in an earlier decline in the incidence of malignant mesothelioma than that predicted for the British workforce as a whole.     

Organophosphate toxicity and occupational exposure

The ubiquitous organophosphates present a continuing health hazard in agriculture, public health eradication programmes and as chemical warfare agents. Despite significant progress in understanding the potential mechanisms of toxicity far beyond the commonly accepted mechanism of cholinesterase inhibition in intentional exposures, the precise health effects following occupational exposures are yet to be completely defined. A much greater understanding exists of the clinical features of organophosphate poisoning. These are characterized by a triphasic response involving an initial acute cholinergic phase, an intermediate syndrome (both associated with high mortality) and a disabling but non-lethal delayed polyneuropathy. The delayed polyneuropathy may occur in the absence of the cholinergic or intermediate phases. However, progress is still required in order to improve the quantification and assessment of occupational exposures and the implementation of appropriate preventive measures. Finally, evidence-based guidelines for appropriate or optimal therapeutic interventions following poisoning are required urgently and collaborative work with colleagues in developing countries, where the occurrence of organophosphate exposures is more frequent, may provide the answers.     

Empathic processes: perception by medical students of patients'' anxiety and depression

Perceptions by medical students of patients' affective states were investigated, and the effect of the students' own emotions on such perceptions. One hundred and one fourth-year medical students rated the levels of anxiety and depression of three women patients presented on videotape, rated their own levels of anxiety and depression and completed a questionnaire on aspects of the rating process. Students had widely different and often inappropriate perceptions of patients' levels of anxiety and depression. Students who consistently overrated anxiety or depression in patients, compared to those who consistently underrated, were themselves significantly more anxious or depressed. These data suggest a need in medical education for systematic teaching of empathic skills and for recognition of potential bias in clinical decision-making arising from the clinician's own emotional state.     

Miliaria rubra of the lower limbs in underground miners

This report documents a case series of miliaria rubra of the lower limbs in miners at a deep underground metalliferous mine in tropical arid Australia. During the summer months of February and March 1999, all cases of miliaria rubra of the lower limbs in underground miners seen at the mine's medical centre were clinically examined and administered a questionnaire. Twenty-five patients were seen, an incidence of 56.4 cases per million man-hours. Miliaria rubra was most often located between the ankle and knee (88% of cases). Twenty-four percent had concurrent folliculitis and 20% had concurrent tinea. Thirty-two percent had a personal history of asthma. Walking through ground-water and splashing of the legs was common. Three to 4 weeks of sedentary duties in air conditioning was generally required to achieve resolution of miliaria rubra. The incidence of miliaria rubra of the lower limbs is 38% of the incidence of heat exhaustion at the same mine. The length of disablement is greater, however. Atopics may be at increased risk of miliaria rubra. Control measures are discussed.