Physical characterization and in vivo organ distribution of coated iron oxide nanoparticles.

Citrate-stabilized iron oxide magnetic nanoparticles (MNPs) were coated with one of carboxymethyl dextran (CM-dextran), polyethylene glycol-polyethylene imine (PEG-PEI), methoxy-PEG-phosphate+rutin, or dextran. They were characterized for size, zeta potential, hysteresis heating in an alternating magnetic field, dynamic magnetic susceptibility, and examined for their distribution in mouse organs following intravenous delivery. Except for PEG-PEI-coated nanoparticles, all coated nanoparticles had a negative zeta potential at physiological pH.

Cow allergen (Bos d2) and endotoxin concentrations are higher in the settled dust of homes proximate to industrial-scale dairy operations.

Airborne contaminants produced by industrial agricultural facilities contain chemical and biological compounds that can impact the health of residents living in close proximity. Settled dust can be a reservoir for these contaminants and can influence long-term exposures. In this study, we sampled the indoor- and outdoor-settled dust from 40 homes that varied in proximity to industrial-scale dairies (ISD; industrial-scale dairy, a term used in this paper to describe a large dairy farm and adjacent waste sprayfields, concentrated animal feeding operation or animal feeding operation, that uses industrial processes) in the Yakima Valley, Washington.

Canadian Forest Fires and the Effects of Long-Range Transboundary Air Pollution on Hospitalizations among the Elderly.

In July 2002, lightning strikes ignited over 250 fires in Quebec, Canada, destroying over one million hectares of forest. The smoke plume generated from the fires had a major impact on air quality across the east coast of the U.S.

Magnetic resonance imaging contrast of iron oxide nanoparticles developed for hyperthermia is dominated by iron content.

Purpose: Magnetic iron oxide nanoparticles (MNPs) are used as contrast agents for magnetic resonance imaging (MRI) and hyperthermia for cancer treatment. The relationship between MRI signal intensity and cellular iron concentration for many new formulations, particularly MNPs having magnetic properties designed for heating in hyperthermia, is lacking. In this study, we examine the correlation between MRI T2 relaxation time and iron content in cancer cells loaded with various MNP formulations.

Characterization of a portable method for the collection of exhaled breath condensate and subsequent analysis of metal content.

Using exhaled breath condensate (EBC) as a biological media for analysis of biomarkers of exposure may facilitate the understanding of inhalation exposures. In this study, we present method validation for the collection of EBC and analysis of metals in EBC. The collection method was designed for use in a small scale longitudinal study with the goal of improving reproducibility while maintaining economic feasibility.

The effect of cell cluster size on intracellular nanoparticle-mediated hyperthermia: is it possible to treat microscopic tumors?

Aim: To compare the measured surface temperature of variable size ensembles of cells heated by intracellular magnetic fluid hyperthermia with heat diffusion model predictions.

Materials & Methods: Starch-coated Bionized NanoFerrite (Micromod Partikeltechnologie GmbH, Rostock, Germany) iron oxide magnetic nanoparticles were loaded into cultured DU145 prostate cancer cells. Cell pellets of variable size were treated with alternating magnetic fields.

Particulate matter air pollution disrupts endothelial cell barrier via calpain-mediated tight junction protein degradation.

Background: Exposure to particulate matter (PM) is a significant risk factor for increased cardiopulmonary morbidity and mortality. The mechanism of PM-mediated pathophysiology remains unknown. However, PM is proinflammatory to the endothelium and increases vascular permeability in vitro and in vivo via ROS generation.

Assessment of heterogeneity of metal composition of fine particulate matter collected from eight U.S. counties using principal component analysis.

The main objectives of this study are to (1) characterize chemical constituents of particulate matter (PM) and (2) compare overall differences in PM collected from eight US. counties. This project was undertaken as a part of a larger research program conducted by the Johns Hopkins Particulate Matter Research Center (JHPMRC).

Preliminary study of injury from heating systemically delivered, nontargeted dextran-superparamagnetic iron oxide nanoparticles in mice.

Aim: To assess the potential for injury to normal tissues in mice due to heating systemically delivered magnetic nanoparticles in an alternating magnetic field (AMF).

Materials & Methods: Twenty three male nude mice received intravenous injections of dextran-superparamagnetic iron oxide nanoparticles on days 1-3. On day 6, they were exposed to AMF.

Use of X-ray absorption spectroscopy to speciate manganese in airborne particulate matter from five counties across the United States.

The purpose of this study is to characterize manganese oxidation states and speciation in airborne particulate matter (PM) and describe how these potentially important determinants of PM toxicity vary by location. Ambient PM samples were collected from five counties across the US using a high volume sequential cyclone system that collects PM in dry bulk form segregated into "coarse" and "fine" size fractions. The fine fraction was analyzed for this study.

Particulate matter induces cardiac arrhythmias via dysregulation of carotid body sensitivity and cardiac sodium channels.

The mechanistic links between exposure to airborne particulate matter (PM) pollution and the associated increases in cardiovascular morbidity and mortality, particularly in people with congestive heart failure (CHF), have not been identified. To advance understanding of this issue, genetically engineered mice (CREB(A133)) exhibiting severe dilated cardiomyopathic changes were exposed to ambient PM collected in Baltimore. CREB(A133) mice, which display aberrant cardiac physiology and anatomy reminiscent of human CHF, displayed evidence of basal autonomic aberrancies (compared with wild-type mice) with PM exposure via aspiration, producing significantly reduced heart rate variability, respiratory dysynchrony, and increased ventricular arrhythmias.

Airborne cow allergen, ammonia and particulate matter at homes vary with distance to industrial scale dairy operations: an exposure assessment.

Background: Community exposures to environmental contaminants from industrial scale dairy operations are poorly understood. The purpose of this study was to evaluate the impact of dairy operations on nearby communities by assessing airborne contaminants (particulate matter, ammonia, and cow allergen, Bos d 2) associated with dairy operations inside and outside homes.

Methods: The study was conducted in 40 homes in the Yakima Valley, Washington State where over 61 dairies operate.

A Scanning Transmission Electron Microscopy Method for Determining Manganese Composition in Welding Fume as a Function of Primary Particle Size.

Increasing evidence suggests that the physicochemical properties of inhaled nanoparticles influence the resulting toxicokinetics and toxicodynamics. This report presents a method using scanning transmission electron microscopy (STEM) to measure the Mn content throughout the primary particle size distribution of welding fume particle samples collected on filters for application in exposure and health research. Dark field images were collected to assess the primary particle size distribution and energy-dispersive X-ray and electron energy loss spectroscopy were performed for measurement of Mn composition as a function of primary particle size.

Design and characterization of a sequential cyclone system for the collection of bulk particulate matter.

In this paper, we describe the design, development and characterization of a high-volume sequential cyclone system for the collection of size-segregated PM in dry bulk form from the ambient environment in sufficient quantity for physical, chemical and toxicological characterization. The first stage of the system consists of a commercially available high volume PM(10) inlet. The second stage cyclone was designed by us to collect inhalable coarse particles (<10 µm and >2.

Ambient air pollution alters heart rate regulation in aged mice.

Context: Heart rate alterations associated with exposure to particulate matter (PM) and gaseous pollutants have been observed in epidemiological studies and animal experiments. Nevertheless, the time-lag of these associations is still unclear.

Objective: Determine the association at different time-lags between the complex mixture of ambient concentrations of PM, carbon monoxide (CO), and nitrogen dioxide (NO(2)), and markers of cardiac function in a model of aged mice.

Emergency admissions for cardiovascular and respiratory diseases and the chemical composition of fine particle air pollution.

Background: Population-based studies have estimated health risks of short-term exposure to fine particles using mass of PM(2.5) (particulate matter View Article and Find Full Text PDF

Particulate matter disrupts human lung endothelial barrier integrity via ROS- and p38 MAPK-dependent pathways.

Epidemiologic studies have linked exposure to airborne pollutant particulate matter (PM) with increased cardiopulmonary mortality and morbidity. The mechanisms of PM-mediated lung pathophysiology, however, remain unknown. We tested the hypothesis that PM, via enhanced oxidative stress, disrupts lung endothelial cell (EC) barrier integrity, thereby enhancing organ dysfunction.

Murine lung responses to ambient particulate matter: genomic analysis and influence on airway hyperresponsiveness.

Background: Asthma is a complex disease characterized by airway hyperresponsiveness (AHR) and chronic airway inflammation. Epidemiologic studies have demonstrated that exposures to environmental factors such as ambient particulate matter (PM), a major air pollutant, contribute to increased asthma prevalence and exacerbations.

Objective: We investigated pathophysiologic responses to Baltimore, Maryland, ambient PM (median diameter, 1.

The longitudinal dependence of black carbon concentration on traffic volume in an urban environment.

The purpose of this study was to evaluate the effect of traffic volume on ambient black carbon (BC) concentration in an inner-city neighborhood "hot spot" while accounting for modifying effects of weather and time. Continuous monitoring was conducted for 12 months at the Baltimore Traffic Study site surrounded by major urban streets that together carry over 150,000 vehicles per day. Outdoor BC concentration was measured with an Aethalometer; vehicles were counted pneumatically on two nearby streets.

Regulation of COX-2 expression and IL-6 release by particulate matter in airway epithelial cells.

Particulate matter (PM) in ambient air is a risk factor for human respiratory and cardiovascular diseases. The delivery of PM to airway epithelial cells has been linked to release of proinflammatory cytokines; however, the mechanisms of PM-induced inflammatory responses are not well-characterized. This study demonstrates that PM induces cyclooxygenase (COX)-2 expression and IL-6 release through both a reactive oxygen species (ROS)-dependent NF-kappaB pathway and an ROS-independent C/EBPbeta pathway in human bronchial epithelial cells (HBEpCs) in culture.

An approach to checking case-crossover analyses based on equivalence with time-series methods.

The case-crossover design has been increasingly applied to epidemiologic investigations of acute adverse health effects associated with ambient air pollution. The correspondence of the design to that of matched case-control studies makes it inferentially appealing for epidemiologic studies. Case-crossover analyses generally use conditional logistic regression modeling.

Comparison of arsenic content in pelletized poultry house waste and biosolids fertilizer.

Managers of human biosolids have been incorporating the practice of waste pelletization for use as fertilizer since the mid 1920s, and waste pelletization has recently been embraced by some poultry producers as a way to move nutrients away from saturated agricultural land. However, the presence of arsenic in pelletized poultry house waste (PPHW) resulting from the use of organoarsenical antimicrobial drugs in poultry production raises concerns regarding additional incremental population exposures. Arsenic concentrations were determined in PPHW and pelletized biosolids fertilizer (PBF) samples.

The world trade center clean up and recovery worker cohort study: respiratory health amongst cleanup workers approximately 20 months after initial exposure at the disaster site.

Objective: Respiratory health among cleanup workers at the World Trade Center (WTC) disaster site was evaluated approximately 20 months after the initial exposure to assess the risk of lower respiratory symptoms.

Methods: In 2003 a self-administered questionnaire requesting information about site experience, current respiratory and historical health, and smoking was sent to 4,546 workers employed at the site (response 25%), and 2103 workers who were never at the WTC (response 12%).

Results: As compared with those never at the site, WTC workers were more than three times as likely to report any lower respiratory symptoms (rate ratio = 3.

Microbial and chemical assessment of regions within New Orleans, LA impacted by Hurricane Katrina.

The city of New Orleans, LA was severely impacted by flooding and wind damage following landfall of Hurricane Katrina in August 2005. The city's drinking water infrastructure was severely compromised and massive amounts of sediment were redeposited throughout the flooded region. Thousands of homes were water-damaged resulting in the rapid growth of mold.