Aspiration toxicology of hydrocarbons and lamp oils studied by in vitro technology

Medical literature regularly reports on accidental poisoning in children after aspiration of combustibles such as lamp oils which usually contain hydrocarbons or rape methyl esters (RMEs). We aimed to analyze the toxic potential of alkanes and different combustible classes in vitro with regard to biologic responses and mechanisms mediating toxicity. Two different in vitro models were used, i.e. (i) a captive bubble surfactometer (CBS) to assess direct influence of combustibles on biophysical properties of surfactant film and (ii) cell cultures (BEAS-2B and R3/1 cells, primary macrophages, re-differentiated epithelia) closely mimicking the inner lung surface. Biological endpoints included cell viability, cytotoxicity and inflammatory mediator release. CBS measurements demonstrate that combustibles affect film dynamics, i.e. the surface tension/area characteristics during compression and expansion, in a dose and molecular chain length dependent manner. Cell culture results confirm the dose dependent toxicity. Generally, cytotoxicity and cytokine release are higher in short-chained alkanes and hydrocarbon-based combustibles than in long-chained substances, e.g. highest inducible cytotoxicity in BEAS-2B was for hexane 84.6%, decane 74% and hexadecane 30.8%. Effects of RME-based combustibles differed between the cell models. Our results confirm data from animal experiments and give new insights into the mechanisms underlying the adverse health effects observed.

Validation of MIPAS IMK/IAA temperature, water vapor, and ozone profiles with MOHAVE-2009 campaign measurements

MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK) and CSIC, Instituto de Astrofísica de Andalucía (IAA) and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infra-red (FTIR) spectrometers. For MIPAS temperatures (version V4O_T_204), no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203) is well within 10% of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40% around 10 km (or 5 km below the tropopause), but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202) has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution. No further significant biases have been detected. Cross-comparison to co-located observations of other satellite instruments (Aura/MLS, ACE-FTS, AIRS) is provided as well.

Different modes of translation for hid, grim and sickle mRNAs in Drosophila

Protein synthesis is inhibited during apoptosis. However, the translation of many mRNAs still proceeds driven by internal ribosome entry sites (IRESs). Here we show that the 5'UTR of hid and grim mRNAs promote translation of uncapped-mRNA reporters in cell-free embryonic extracts and that hid and grim mRNA 5'UTRs drive IRES-mediated translation. The translation of capped-reporters proceeds in the presence of cap competitor and in extracts where cap-dependent translation is impaired. We show that the endogenous hid and grim mRNAs are present in polysomes of heat-shocked embryos, indicating that cap recognition is not required for translation. In contrast, sickle mRNA is translated in a cap-dependent manner in all these assays. Our results show that IRES-dependent initiation may play a role in the translation of Drosophila proapoptotic genes and suggest a variety of regulatory pathways.