Dust exposure in Munich public transportation: a comprehensive 4-year survey in buses and trams

Objectives: Published data obtained from outdoor stationary sampling stations cannot be applied directly to the exposure situation in vehicles. The aim of this study, therefore, was to assess the dust exposure relevant to passengers and drivers in public buses and trams. Method: In the years 1993 to 1996, PM₁₀ samples were taken during 201 journeys of typically 4 h duration on 14 routes (nine bus routes, five tramways) which were representative for the overall Munich transportation system with respect to area characteristics and traffic density. The concentrations of the samples were compared with those collected at the same time at sampling stations of the Bavarian State Office for Environmental Protection (OEP). Dust exposure was continuously and synchronously recorded by means of a tyndallometric device. Traffic and passenger density, weather conditions, special events, etc. were noted by our personnel, travelling on every journey. Results: The average PM₁₀ dust concentration for all rides was 155 μg/m³ (single journey max. 686 μg/m³, min. 13 μg/m³). Interior concentrations were 1.7 to 4.0 times above those collected at the static outdoor stations. We found only minor associations between dust concentrations and traffic density or time of day. During several journeys continuous recording disclosed anomalies, dependence on weather conditions and cyclic track characteristics. Conclusions: Interior PM₁₀ particulate concentrations were comparable to those found elsewhere in truck drivers' cabs and are in the region of German regulative limits established for the general population's long term outdoor exposure. Indoor concentrations were well above the values found at stationary outdoor stations. Additional continuous recording of dust concentrations proved to be helpful in unveiling anomalies and dependencies on external effectors. Received: 10 August 1999 / Accepted: 20 November 1999     

Priapism induced by intracavernosal vasoactive intestinal polypeptide and phentolamine mesylate

This is a case of priapism (21 h) following an intracavernosal injection of vasoactive intestinal polypeptide (VIP) 25 mcg with phentolamine mesylate (PM) 1 mg responding to venesection and intracavernosal injection of 1 mg metaraminol.     

Redox activity of airborne particulate matter at different sites in the Los Angeles Basin

Epidemiologic studies have shown associations between ambient particulate matter (PM) and adverse health outcomes including increased mortality, emergency room visits, and time lost from school and work. The mechanisms of PM-related health effects are still incompletely understood, but a hypothesis under investigation is that many of the adverse health effects may derive from oxidative stress, initiated by the formation of reactive oxygen species (ROS) within affected cells. While the adverse effects from PM have historically been associated with the airborne concentration of PM and more recently fine-particle PM, we considered it relevant to develop an assay to quantitatively measure the ability of PM to catalyze ROS generation as the initial step in the induction of oxidative stress. This ability of PM could then be related to different sources, chemical composition, and physical and spatial/temporal characteristics in the ambient environment. The measurement of ROS-forming ability in relation to sources and other factors will have potential relevance to control of redox-active PM. If oxidative stress represents a relevant mechanism of toxicity from PM, the measurement of redox activity represents a first step in the elucidation of the subsequent downstream processes. We have developed an assay for PM redox activity, utilizing the reduction of oxygen by dithiothreitol which serves as an electron source. We have found that PM will catalyze the reduction of oxygen and have examined the distribution and chemical characteristics of the redox activity of PM fractions collected in different sites in the Los Angeles Basin. Samples of concentrated coarse, fine, and ultrafine PM, obtained with aerosol concentrators, were studied with regard to their chemical properties and redox activity. Redox activity was highest in the ultrafine fraction, in agreement with results indicating ultrafines were the most potent toward inducing that heme oxygenase expression and depleting intracellular glutathione, which has relevance to induction of oxidative stress. Comparison of the redox activity with chemical composition showed a reasonable correlation of redox activity with elemental carbon (r(2)=0.79), organic carbon (r(2)=0.53), and with benzo[ghi]perylene (r(2)=0.82), consistent with species typically found in mobile emission sources.     

Effects of ambient particulate matter on peak expiratory flow rates and respiratory symptoms of asthmatics during Asian dust periods in Korea

OBJECTIVE: Dust generating events frequently produce ambient dust particles that are less than 10 microm in diameter, and these have been linked to adverse effects in the general population. However, the evidence linking these particles to adverse effects on the airways of asthmatic individuals is limited. The objective of this study was to investigate the possible adverse effects of Asian dust events on the respiratory functions and symptoms of subjects with bronchial asthma. METHODOLOGY: From March to June 2002, individuals were enrolled who had been diagnosed as having asthma by bronchial challenge or by their bronchodilator response. The patients were divided into three groups according to asthma severity: mild, moderate and severe. Patients with other major disease states were excluded. Patients completed twice-daily diaries monitoring PEF, respiratory symptoms, and daily activities. The daily and hourly mean levels of particulate matter <10 microm in diameter (PM(10)), as well as nitrogen dioxide (NO(2)), sulphur dioxide (SO(2)), ozone (O(3)) and carbon monoxide (CO) were measured at 10 monitoring sites in Incheon, Korea. RESULTS: Dust events occurred 14 times during the study period. On dusty days there were increased levels of PM(10), decreased levels of NO(2) and SO(2), and no change in the CO levels, compared to the levels on control days. An increase in PM(10) concentration was associated with increases in PEF variability of >20% (P<0.05), more night-time symptoms (P<0.05), and a decrease in the mean PEF (P<0.05), calculated by longitudinal data analysis. In contrast, there was no association between the PM(10) levels and bronchodilator inhaler use or daytime respiratory symptoms. Using a general additive Poisson regression model, a borderline association was noted between PM(10) and respiratory symptoms, with a relative risk of 1.05 (95% confidence interval (CI), 0.99--1.17). There was no association between the PM(10) concentrations and PEF measurements, with PEF variability of >20% between the morning and evening values and a relative risk of 1.05 (95% CI, 0.89--1.24) in all subjects. CONCLUSIONS: This study provides evidence that Asian dust events are impacting on the respiratory symptoms of subjects with bronchial asthma, and ambient air pollution, particularly elevated PM(10), might be one of the aggravating factors.     

Dual effect of hydrogen peroxide on store-mediated calcium entry in human platelets

Redox regulation is important for the modulation of cytosolic Ca(2+) concentration. Hence, we have investigated the effect of H(2)O(2) on store-mediated Ca(2+) entry (SMCE). In fura-2-loaded human platelets treatment with H(2)O(2) resulted in a concentration-dependent increase in Ca(2+) release from intracellular stores, while the effect on Ca(2+) entry was biphasic. In addition, 1mM H(2)O(2) reduced SMCE induced by agonists. The inhibitory effect of 1mM H(2)O(2) was prevented by inhibition of actin polymerization with cytochalasin D. Consistent with this, we found that 10microM H(2)O(2) and store depletion by treatment with thapsigargin plus ionomycin induced a similar temporal sequence of actin reorganization, while exposure to 1mM H(2)O(2) shifted the dynamics between polymerization and depolymerization in favor of the former. One millimolar H(2)O(2)-induced polymerization was reduced by treatment with methyl 2,5-dihydroxycinnamate and farnesylthioacetic acid, inhibitors of tyrosine kinases and Ras superfamily proteins, respectively. Finally, exposure to 1mM H(2)O(2) significantly increased store depletion-induced p60(src) activation. We conclude that H(2)O(2) exerted a biphasic effect on SMCE. The inhibitory role of high H(2)O(2) concentrations is mediated by an abnormal actin reorganization pattern involving both Ras- and tyrosine kinases-dependent pathways.     

杭州市大气PM2.5中的碳氮氢和重金属

目的：探讨杭州市区大气PM2.5中重金属和碳氮氢的污染状况。方法：用中流量气溶胶采样器在市区采集了大气样品,以燃烧法和微波消解-电感耦合等离子体质谱法分别检测了PM2.5中碳氮氢和重金属的组成。结果：在杭州市中心和市区东北部大气PM2.5中,N、C、H的年平均浓度分别为13.9～14.7、30.3～30.8、7.9～8.9μg/m^3。全市PM2.5中N、C、H的年平均质量含量分别为12.8%、27.8%、8.1%。IN/ON、OH/IH的年平均值分别为2.2～3.5、3.5～3.6。在市中心,IN的四季平均含量为8.0%～9.5%,IH为1.9%～2.1%,ON为3.6%～5.7%,OH为5.9%～8.7%。在城区东北部,IN的四季平均含量为7.8%～8.1%,IH为1.8%～1.9%,ON为3.0%～5.4%,OH为4.3%～7.5%。PM2.5中11种元素的含量较高,其中Zn、Pb、Cu、Mn的含量在0.1‰以上,Cr、Ni、Se、Mo、Cd、Sb的含量在0.01‰～0.1‰之间,Ag的含量最低,在0.01‰以下。这11种元素在PM2.5中的年平均质量含量为17‰～20‰。结论：碳是PM2.5的重要组成部分。氮、氢分别主要以无机氮和有机氢的形式存在。Zn、Pb、Cu、Mn是主要重金属污染元素。     

Pre- and postnatal exposure to ambient levels of urban particulate matter (PM2.5) affects mice spermatogenesis

This work characterizes the effects of ambient levels of urban particulate matter (PM_2.5) from the city of Sao Paulo on spermatogenesis using mice exposed during the embryo–fetal and/or postnatal phases of development. Parental generations (BALB/c mice) were exposed to air pollution in chambers with or without filtering PM_2.5 for 4 months. Animals were mated, and half of the 1-day-old offspring were moved between chambers, which yielded prenatal and postnatal groups. Remaining offspring comprised the non-exposed and pre+postnatal exposed groups. After 90 days, the animals were sacrificed for testis collection and weighing. Optical microscopy was used for the morphometric analyses of the cell counts, spermatogenic cycle, proliferation, and apoptosis. Prenatally exposed animals presented reduced body and testicular weight with an increased gonadosomatic index (GSI). Testicular volume also decreased, as well as the tubular diameter in testes of the same animals. Proliferation, apoptosis, and spermatogenic cycle analyses showed no significant differences among groups. However, the tubules at stage VII of pre- and postnatal animals presented a reduced number of elongated spermatids. Pre+postnatal group presented higher spermatid head retention at stages VIII–XII. These results show that ambient levels of PM_2.5 from Sao Paulo city affect spermatogenesis by damaging sperm production.     

Conjugated linoleic acid alters caveolae phospholipid fatty acid composition and decreases caveolin-1 expression in MCF-7 breast cancer cells

Conjugated linoleic acid (CLA) refers to a group of biologically active fatty acids that exhibit anticarcinogenic properties; however, the mechanism of action remains poorly understood. Caveolae are specialized plasma membrane structures that affect many facets of cancer cell function, including growth, cell signaling, and apoptosis. Therefore, one potential mechanism could be alteration of caveolae lipid composition and function. We hypothesized that CLA can alter the lipid microenvironment of caveolae and alter expression of the major caveolae-resident protein, caveolin-1. MCF-7 human breast cancer cells were treated with a vehicle control, linoleic acid (LA), or CLA for 3 days after which total cell lysate, plasma membrane, and caveolae membrane fractions were isolated. Our findings indicate that CLA readily incorporates into caveolae (Δ9cis,11trans-18:2 being the major isomer) and maybe preferentially enriched in specific phospholipid species. Furthermore, caveolin-1 localization to caveolae after treatment with CLA was decreased relative to either control- or LA-treated cells, without changes in total cellular levels of protein relative to vehicle-control treated cells. Taken together, our results suggest that further investigation of a potential therapeutic role for CLA in modulating caveolae function in breast cancer is merited.     

Application of polymer-mesh device to remodel left ventricular–mitral valve apparatus in ischemic mitral regurgitation

Objectives

Ischemic mitral regurgitation (IMR) results from ischemic left ventricular (LV) distortion and remodeling, which displaces the papillary muscles and tethers the mitral valve leaflets apically. The aim of this experimental study was to examine efficacy of an adjustable novel polymer filled mesh (poly-mesh) device to reverse LV remodeling and reduce IMR.

北京市环境空气放射性水平的测量与分析

目的 探讨环境空气放射性水平及与空气质量的关系。方法 选取2017年9月-12月期间,以SNOW WHITE大流量采样器进行空气样品收集,连续24 h采样,以TBM-3S测量仪对收集的样品滤膜表面进行表面放射性测量,将测得结果分别与空气质量等级、大气中PM_2.5、PM₁₀颗粒物浓度进行统计学比较分析。结果 37个大气气溶胶滤膜样品的表面放射性水平为（1.051~2.831）Bq/cm²,平均值为1.802 Bq/cm²;不同空气质量等级间比较大气中放射性水平无显著性差异（P ≥ 0.05）,不同颗粒物浓度间比较大气中放射性水平无显著性差异（P ≥ 0.05）。结论 监测期间,空气质量及大气中颗粒物含量的变化,未引起大气中放射性水平的变化,空气质量与大气放射性水平不相关。