DNA Adduct Formation in the Lungs and Brain of Rats Exposed to Low Concentrations of [13C2]-Acetaldehyde.

Air pollution is a major environmental risk for human health. Acetaldehyde is present in tobacco smoke and vehicle exhaust. In this study, we show that [13C2]-acetaldehyde induces DNA modification with the formation of isotopically labeled 1, N2-propano-2'-deoxyguanosine adducts in the brain and lungs of rats exposed to concentrations of acetaldehyde found in the atmosphere of megacities. The adduct, with the addition of two molecules of isotopically labeled acetaldehyde [13C4]-1, N2-propano-dGuo, was detected in the lung and brain tissues of exposed rats by micro-HPLC/MS/MS. Structural confirmation of the products was unequivocally performed by nano-LC/ESI+-HRMS3 analyses. DNA modifications induced by acetaldehyde have been regarded as a key factor in the mechanism of mutagenesis and may be involved in the cancer risks associated with air pollution.

Integrated instrumental analysis teaching platform with smartphone-operated fluorometer.

The present work describes an Integrated Teaching Tool (ITT) to facilitate the learning process in analytical chemistry. The first instrument integrated in the platform to demonstrate the concept is a wireless, portable fluorometer, produced by 3D printing. The low-cost instrument features a Teensy 3.1 board as the microcontroller, a high-power UV-LED, a secondary filter, a photodiode, and simple auxiliary electronic circuits. Modules of the ITT app were designed to manage the instrument and perform data acquisition remotely from any Android smartphone via Bluetooth, plot and transmit the results. Supporting the educational purpose of the platform, examples of basic concepts about fluorescence as well as technical information about the instrument are also provided to be considered for the app, which also allows instructors to assist and evaluate students through push notifications.

Quantification of DNA adducts in lungs, liver and brain of rats exposed to acetaldehyde.

Air pollution is a major risk for human health. Acetaldehyde is an environmental pollutant present in tobacco smoke, vehicle exhaust and several food products. Formation of DNA adducts has been regarded as a critical factor in the mechanisms of acetaldehyde mutagenicity and carcinogenesis. Acetaldehyde reacts with 2'-deoxyguanosine in DNA to primarily form N(2)-ethylidene-2'-deoxyguanosine (N(2)-ethylidene-dGuo). The subsequent reaction of N(2)-ethylidene-dGuo with another molecule of acetaldehyde gives rise to 1,N(2)-propano-2´-deoxyguanosine (1,N(2)-propanodGuo). In this study, on-line reverse-phase high-performance liquid chromatography (HPLC) separation with tandem mass spectrometry detection was utilized for the accurate quantification of 1,N(2)-propanodGuo and 1,N(2)-etheno-2'-deoxyguanosine (1,N(2)-edGuo) in tissues of rats exposed to 12 ppb, 33 ppb and 96 ppb acetaldehyde in atmospheric air for 50 days. A significant increase in the levels of 1,N(2)-propanodGuo was observed in lung tissues of rats exposed to 12 ppb (7.8/10(8) dGuo); 33 ppb (8.9/10(8) dGuo) and 96 ppb (11.6/10(8) dGuo) compared to controls (4.2/10(8) dGuo). For comparative purposes, the levels of 1,N(2)-etheno-2'-deoxyguanosine (1,N(2)-edGuo), which is produced from a,b-unsaturated aldehydes formed during the lipid peroxidation process were also measured. Elevated levels of 1,N(2)-edGuo were observed only in lung tissues of animals exposed to 96 ppb acetaldehyde. 1,N(2)-propanodGuo also differed quantitatively in liver but not in brain. The monitoring of 1,N(2)-propanodGuo levels in tissues provides important information on acetaldehyde genotoxicity and may contribute to the elucidation of the mechanisms associated with acetaldehyde exposure and cancer risk. Supported byFAPESP:2011/10048-5, CAPES, INCT Redoxoma:573530/2008-4,NAP Redoxoma: 2011.1.9352.1.8, CEPID Redoxoma:2013/07937-8.