Reduced in vitro toxicity of fine particulate matter collected during the 2008 Summer Olympic Games in Beijing: the roles of chemical and biological components.

Beijing has implemented systematic air pollution control legislation to reduce particulate emissions and improve air quality during the 2008 Summer Olympics, but whether the toxicity of fine fraction of particles (PM(2.5)) would be changed remains unclear. In present study we compared in vitro biological responses of PM(2.

Selection and evaluation of stable housekeeping genes for gene expression normalization in carbon nanoparticle-induced acute pulmonary inflammation in mice.

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) is a highly specific and sensitive technique for the quantification of gene expression on the mRNA levels. But use of unconfirmed housekeeping genes (HKGs) could lead to misinterpretation of the expression of genes of interest (GOI). In this study, the stability and suitability of 11 frequently used housekeeping genes, namely 18S rRNA, ACTB, B2M, CYPA, GADPH, GUSB, HMBS, HPRT1, RPL13A, SDHA and TBP in 36 lung tissues isolated from either wild-type (WT) mice or p50 knock out (p50-/-) mice or p105 knock-out (p105-/-) mice which were treated with either carbon nanoparticle (CNP) or H(2)O or non-treated, have been validated by geNorm, NormFinder and BestKeeper programs.

Deducing in vivo toxicity of combustion-derived nanoparticles from a cell-free oxidative potency assay and metabolic activation of organic compounds.

Background: The inhalation of combustion-derived nanoparticles (CDNPs) is believed to cause an oxidative stress response, which in turn may lead to pulmonary or even systemic inflammation.

Objective And Methods: In this study we assessed whether the in vivo inflammatory response--which is generally referred to as particle toxicity-of mice to CDNPs can be predicted in vitro by a cell-free ascorbate test for the surface reactivity or, more precisely, oxidative potency (OxPot) of particles.

Results: For six types of CDNPs with widely varying particle diameter (10-50 nm), organic content (OC; 1-20%), and specific Brunauer, Emmett, and Teller (BET) surface area (43-800 m2/g), OxPot correlated strongly with the in vivo inflammatory response (pulmonary polymorphonuclear neutrophil influx 24 hr after intratracheal particle instillation).