Epigenetic alterations induced by ambient particulate matter in mouse macrophages

Respiratory mortality and morbidity has been associated with exposure to particulate matter (PM). Experimental evidence suggests involvement of cytotoxicity, oxidative stress, and inflammation in the development of PM‐associated pathological states; however, the exact mechanisms remain unclear. In the current study, we analyzed short‐term epigenetic response to PM₁₀ (particles with aerodynamic diameter less than 10 μm) exposure in mouse ascitic RAW264.7 macrophages (BALB/C Abelson murine leukemia virus‐induced tumor). Ambient PM₁₀ was collected using a high volume sampler in Little Rock, AR. Analysis revealed that PM₁₀ was composed mainly of Al and Fe, and the water soluble organic fraction was dominated by aliphatic and carbohydrate fragments and minor quantities of aromatic components. Exposure to PM₁₀ compromised the cellular epigenome at concentrations 10–200 µg/ml. Specifically, epigenetic alterations were evident as changes in the methylation and expression of repetitive element‐associated DNA and associated DNA methylation machinery. These results suggest that epigenetic alterations, in concert with cytotoxicity, oxidative stress, and inflammation, might contribute to the pathogenesis of PM‐associated respiratory diseases. Environ. Mol. Mutagen. 55:428–435, 2014. © 2014 Wiley Periodicals, Inc.     

利用蒙特卡罗模拟评估空气间隙对点扫描质子治疗的剂量影响

目的:利用蒙特卡罗模拟探究空气间隙对点扫描质子治疗的剂量影响。方法:利用通用蒙特卡罗程序Geant4平台构建使用射程移位器的治疗头末端的点扫描质子束流模型,并进行验证。模拟计算不同能量、不同射程移位器、不同束斑尺寸、不同束斑数目在不同空气间隙条件下的质子束流在水模体中的剂量沉积,并通过获得的积分深度剂量生成剂量修正因子对剂量的差异进行比较。结果:不同空气间隙会造成剂量损失,随空气间隙增大而增大,随水模体中深度增加而减小。对于能量更高的射束和使用水等效厚度更薄的射程移位器,剂量损失越大。束斑尺寸改变和束斑数目增加较少时造成的剂量损失与同条件下单一束流无显著差别。结论:当使用射程移位器、肿瘤位置较浅、空气间隙较大时,建议建立剂量修正因子数据库应用于治疗计划系统对剂量进行修正。     

The child with recurrent respiratory infections: normal or not?

Respiratory infections (RI) are one of the major complaints in children and adolescents, and represent a demanding challenge for the pediatrician. It has been estimated that at least 6% of Italian children younger than 6 yr of age present recurrent respiratory infections (RRI). Children with RRI are not affected by severe alterations of the immune system. RRI represent essentially the consequence of an increased exposure to infectious agents during the first years of life, when immune functions are still largely immature. Several social and environmental factors, such as day-care attendance, family size, air pollution, parental smoking, and home dampness, represent important risk factors for airway diseases and may contribute in various degrees to determine the incidence of RRI. The main problem for the pediatrician is to discriminate normal children with high RI frequency related to an augmented exposure to environmental risk factors from children affected by other underlying pathological conditions (immunological or not), predisposing to infectious diseases. When RRI diagnosis has been formulated, removal of environmental risk factors (i.e. precocious day-care attendance, smoking in the household) must first be suggested.     

Cleansing technique using high-velocity steam–air micromist jet spray

Application of a high-velocity steam–air micromist jet spray (HVS-AMJS; micromist average diameter: 2.4?μm) for cleansing the skin is proposed. Low-pressure steam is mixed with compressed air (pH 6.5) in a nozzle, and then sprayed at a pressure of ≦0.25?MPa and a velocity of ≧0.34?m/s on the skin or surface of material located approximately 5–10?cm from the nozzle. The temperature on the sprayed surface and water flow rate could be controlled between 42?°C and 46?°C and at approximately 50?mL/min, respectively. Compared with ultrasonic cleansing with tap water and rubbing with only tap water, the HVS-AMJS successfully removed fluorescent lotion covering pieces of wood and significantly reduced both the number of coliforms and the total viable counts on pieces of wood and gauze. Furthermore, the HVS-AMJS effectively removed oily ink from the skin of hairless rats, and temporarily elevated the skin temperature and blood flow, indicating massage effects. The striking characteristics of this cleansing technique using HVS-AMJS are not only its ability to remove microbes and residue without using any chemicals or detergents but also its massage effects.     

NANC nerves in the respiratory air sac and branchial vasculature of the Indian catfish,Heteropneustes fossilis

Gill and air sac of the Indian catfish Heteropneustes fossilis harbour a nerve network comprising an innervated system of neuroepithelial endocrine cells; the latter cells are found especially in the gill. A series of antibodies was used for the immunohistochemical detection of neurotransmitters of the neural non-adrenergic, non-cholinergic (NANC) systems such as the sensory neuropeptides (enkephalins), the inhibitory neuropeptide VIP and neuronal nitric oxide synthase (nNOS) responsible for nitric oxide (NO) production which is an inhibitory NANC neurotransmitter. NADPH-diaphorase (NADPH-d) histochemistry was used as marker of nNOS although it is not a specific indicator of constitutively-expressed NOS in gill and air sac tissues. A tyrosine hydroxylase antibody was used to investigate adrenergic innervation. Nitrergic and VIP-positive sensory innervation was found to be shared by gill and air sac. Immunohistochemistry revealed the presence of enkephalins, VIP, NOS and NADPH-d in nerves associated with branchial and air sac vasculature, and in the neuroendocrine cell systems of the gill. Adrenergic nerve fibers were found in some parts of the air sac vasculature. The origin of the nerve fibers remains unclear despite previous findings showing the presence of both NADPH-d and nNOS in the sensory system of the glossopharyngeal and vagus nerves including the branchial structure. Scarce faintly stained nNOS-positive neurons were located in the gill but were never detected in the air sac. These findings lead to the conclusion that a postganglionic innervation of the airways is absent. Mucous goblet cells in the gill were found to express nNOS and those located in the non-respiratory interlamellar areas of the air sac were densely innervated by nNOS-positive and VIP-positive nerve fibers. Our immunohistochemical studies demonstrate that most arteries of the gill and air sac share a NANC (basically nitrergic) innervation which strongly suggests that they are homologous structures.     

Dustborne and airborne fungal propagules represent a different spectrum of fungi with differing relations to home characteristics

BACKGROUND: Exposure to fungi is often assessed by culturing floor dust or air samples. Our objective was to evaluate the relationships between dustborne and airborne fungi and to identify factors that modify these relationships. METHODS: From November 1994 to September 1996 sequential duplicate 45-l air samples were collected in bedrooms of 496 homes in the Boston area, using a Burkard culture plate sampler. After air sampling, bedroom floors were sampled with a vacuum cleaner that was modified to collect dust in a cellulose extraction thimble. Dust was sieved, and the fine dust was dilution-plated onto DG-18 media. RESULTS: Concentrations of total culturable fungi per gram of bedroom-floor dust were correlated weakly, but significantly, with those of indoor air (r = 0.13, P < 0.05). Concentrations of some individual taxa in the dust and indoor air were also weakly associated. Adjusting for the concentrations of fungi in outdoor air, dustborne fungal concentrations were positively associated with those in indoor air for the taxa Cladosporium and Penicillium, but not for total fungi. The indoor air fungal levels were often predicted by different covariates to those predicting fungal levels in dust. The type of housing (house or apartment) and the presence of carpeting were often predictive factors for dust fungi. In contrast, outdoor fungal levels were often predictive of the indoor air fungal levels. CONCLUSIONS: Because our data do not indicate a strong overall relationship between culturable fungi in dust and indoor air, the results from these two methods (dust and air sampling) likely represent different types of potential fungal exposures to residents. It may be essential to collect both air and dust samples, as well as information on housing characteristics, as indicators for fungal exposure.     

地下空间空气环境影响因素分析

分析了地下空间温湿度特性,以及放射性污染、微生物、有害气体、固体颗粒物等地下空间空气环境的影响因素,因地制宜采取防潮、通风、除尘、杀菌消毒等措施是改善地下空气环境的有效途径,独立除湿技术、增加空气负离子也是提高空气品质的有效措施。     

浅析医用压缩空气系统供气安全

医用压缩空气作为生命支持系统中最为重要的气体之一,必须对系统中的每个环节都要做细致周密的考虑才能保证提供给患者安全的空气。本文结合医院新购买的美国必康美德（BeaconMedaes）医用无油压缩系统及美国NFPA99医用气体标准,介绍如何选择安全的压缩空气系统。     

生物医药工程人防规划设计的解析和思考

目的对生物医药工程人防工程规划设计各要素进行分析、探讨。方法通过工程项目实例建设情况,分析目前我国人防工程现状和规划设计存在的问题,提出解决方案。结果与结论 应加强工程规划设计管理,合理利用资源,提高生物医药人防工程的社会效益和经济效益。     

甘氨酸龈下喷砂联合引导组织再生术治疗种植体周围炎

目的探讨甘氨酸龈下喷砂联合引导组织再生术（GTR）治疗种植体周围炎的有效性。 方法28例伴有牙槽骨吸收的种植体周围炎患者,按照随机、双盲、对照原则将种植体（共34枚）分成2组,分别行GTR,其中试验组（n= 18）在术中使用甘氨酸龈下喷砂系统对种植体表面进行清创;对照组（n= 16）采用塑料刮治器对种植体表面进行清创。在治疗前（基线）、治疗后3个月、治疗后6个月和治疗后12个月进行临床指标的检测,包括菌斑指数（PLI）、出血指数（BI）、探诊深度（PD）、临床附着水平（CAL）及影像学垂直骨增量。数据采用重复测量资料的方差分析,每个时间点采用独立样本t检验进行分析,试验组和对照组分别进行治疗前与治疗后的自身对比,并在基线、治疗后3个月、治疗后6个月和治疗后12个月进行临床指标的组间对比,以P<0.05为差异有统计学意义。 结果在基线,试验组和对照组各临床指标差异无统计学意义（P>0.05）。各组术后PLI、BI、PD、CAL及影像学垂直骨增量均较治疗前（基线）有明显改善,差异有统计学意义（P<0.05）。患者治疗后3个月,试验组与对照组BI、PLI、PD、CAL差异均有统计学意义（t_BI= 5.103,P_BI= 0.031;t_PLI= 5.556,P_PLI= 0.025;t_PD= 4.440,P_PD= 0.043;t_CAL= 4.879,P_CAL= 0.034）。患者治疗后6个月,试验组和对照组的PD、CAL差异均有统计学意义（t_PD= 4.994,P_PD= 0.033;t_CAL= 4.831,P_CAL= 0.035）。患者治疗后12个月,试验组和对照组的PD、CAL差异均有统计学意义（t_PD= 4.302,P_PD= 0.046;t_CAL= 4.325,P_CAL= 0.048）。患者治疗后6及12个月,试验组与对照组种植体的PLI和BI均有改善,但差异无统计学意义（P>0.05）。患者影像学垂直骨增量在治疗后3、6、12个月试验组较对照组增加更明显,差异均有统计学意义（t₃=4.831,P₃= 0.035;t₆= 4.412,P₆= 0.044;t₁₂= 5.087,P₁₂= 0.031）。 结论在改善种植体周围炎炎症水平及促进牙槽骨再生方面,甘氨酸龈下喷砂联合GTR较机械刮治联合GTR更具优势,可考虑在GTR中使用甘氨酸龈下喷砂来提高种植体周围炎的治疗效果。