Chen J, Cha-Molstad H, Szabo A, Shalev A. Diabetes induces and calcium channel blockers prevent cardiac expression of proapoptotic thioredoxin-interacting protein.

Previous studies demonstrated methane generation in aerobic cells. Our aims were to investigate the methanogenic features of sodium azide (NaN(3))-induced chemical hypoxia in the whole animal and to study the effects of l-α-glycerylphosphorylcholine (GPC) on endogenous methane production and inflammatory events as indicators of a NaN(3)-elicited mitochondrial dysfunction. Group 1 of Sprague-Dawley rats served as the sham-operated control; in group 2, the animals were treated with NaN(3) (14 mg·kg(-1)·day(-1) sc) for 8 days. In group 3, the chronic NaN(3) administration was supplemented with daily oral GPC treatment. Group 4 served as an oral antibiotic-treated control (rifaximin, 10 mg·kg(-1)·day(-1)) targeting the intestinal bacterial flora, while group 5 received this antibiotic in parallel with NaN(3) treatment. The whole body methane production of the rats was measured by means of a newly developed method based on photoacoustic spectroscopy, the microcirculation of the liver was observed by intravital videomicroscopy, and structural changes were assessed via in vivo fluorescent confocal laser-scanning microscopy. NaN(3) administration induced a significant inflammatory reaction and methane generation independently of the methanogenic flora. After 8 days, the hepatic microcirculation was disturbed and the ATP content was decreased, without major structural damage. Methane generation, the hepatic microcirculatory changes, and the increased tissue myeloperoxidase and xanthine oxidoreductase activities were reduced by GPC treatment. In conclusion, the results suggest that methane production in mammals is connected with hypoxic events associated with a mitochondrial dysfunction. GPC is protective against the inflammatory consequences of a hypoxic reaction that might involve cellular or mitochondrial methane generation.

Aerobic methane generation was demonstrated earlier in plants and eukaryotes under various stress conditions. Our aims were to develop a real-time and noninvasive detection system for monitoring the methane production of small animals and humans with our without exposure to various treatments. A near-infrared diode laser technique was employed with photoacoustic spectroscopy to monitor a methane-containing atmosphere online. The whole-body methane generation of anesthetized mice and rats was determined under baseline conditions and following reduction of the intestinal methanogenic flora or after lipopolysaccharide administration. Single-breath methane analyses were also carried out in a cross-sectional clinical study in order to obtain comparative human data. The whole-body methane production of mice was significantly decreased after antibiotic treatment (M: 1.71 ppm cm(-2) 10(3); p25: 1.5 ppm cm(-2) 10(3); p75: 2.11 ppm cm(-2) 10(3)) and increased significantly in endotoxemia (M: 4.53 ppm cm(-2) 10(3); p25: 4.37 ppm cm(-2) 10(3); p75: 5.38 ppm cm(-2) 10(3)), while no difference was observed between the rat groups. The methane content of the exhaled breath in humans was found to be between 0 and 37 ppm. Photoacoustic spectroscopy is a reliable tool with which to monitor the in vivo dynamics of stress-induced methane production in laboratory animals, even in a very low concentration range.

This paper describes a photoacoustic spectroscopy-based detector of hydrogen sulfide (H2S) in biogas, natural gas and oil process technology. The instrument is capable of measuring H2S concentrations over four orders of magnitude (from a few ppm level up to several per cent) in changing gas mixtures. Problems caused by harsh industrial circumstances, contamination and widely varying composition of gases can be overcome by optimizing wavelength modulation, resonance frequency tracking and an easy-to-use method enabling in situ monitoring calibration. A diode laser emitting around 1.57 µm served as the excitation source; at this wavelength spectral overlap between H2S and CO2 is substantial. Spectral interference was eliminated by optimizing the amplitude of wavelength modulation; furthermore, a simplified calibration method was implemented taking advantage of a nearby absorption line of CO2 providing fast and economical measurements. Frequency dependence of the photoacoustic signal was determined by two methods to ensure accuracy. For 10 s integration time and 6800 Hz modulation frequency, the minimum detectable concentration was 6 ppm (3σ).

We describe a novel chemical mitogen-free in vitro culture technique for obtaining pure melanocyte cultures using normal human adult epidermis as a source. The culture medium consists equal parts of the commercially available Keratinocyte Basal and AIM-V media (both from Gibco), as basal medium, which is supplemented with fetal bovine serum, bovine pituitary extract and recombinant human epidermal growth factor (EGF). Melanocytes harvested from human adult skin proliferate extensively and can be passaged serially up to 10-15 times using this medium. We have verified the identity of the cultured cells by tyrosinase mRNA expression and TRP-1 protein staining. Moreover, we showed that autologous human serum alone, without additional supplements is able to provide sufficient growth support for the cultured cells in the basal medium, making this culture technique suitable for autologous melanocyte transplantation. In this culture system normal human adult melanocytes expressed both EGF receptor (EGFR) mRNA and protein and EGF showed a dose dependent mitogenic effect on the cells. EGF itself had no significant influence on EGFR mRNA expression.