Determination of ambient ethanol concentrations in aqueous environmental matrixes by two independent analyses.

A new method for the determination of ethanol in aqueous environmental matrixes at nanomolar concentrations is presented and compared to an existing method that has been optimized for low-level alcohol determinations. The new analysis is based upon oxidation of ethanol by the enzyme alcohol oxidase obtained from the yeast Hansenula sp. which quantitatively produces acetaldehyde after reaction for 120 min at 40 °C and pH 9.0. The acetaldehyde reacts with 2,4-dinitrophenylhydrazine forming a hydrazone that is separated from interfering substances and quantified by high-performance liquid chromatography (HPLC) with UV detection at 370 nm. Comparison of initial acetaldehyde concentration with that after enzymatic oxidation yields the ethanol concentration with a corresponding detection limit of 10 nM. Analytical results were verified by intercomparison with a completely independent technique utilizing a solid-phase microextraction (SPME) Carboxen/PDMS SPME fiber. A 12 mL aqueous phase sample was heated at 50 °C for 10 min prior to loading onto the SPME fiber. Extraction of ethanol was performed by introducing the fiber into the headspace above a pH 4.4 buffered sample containing 30% NaCl for 20 min. Samples were agitated during heating and extraction by magnetic stirring at a rate of 750 rpm. The fiber was thermally desorbed for 1 min at 230 °C in the injection port of a gas chromatograph equipped with a flame ionization detector (FID) set at 250 °C. The resulting ethanol detection limit is 19 nM. Results of an intercomparison study between the enzymatic and SPME analyses produced a trend line with a slope of unity demonstrating that methods produced statistically equivalent ethanol concentrations in several natural waters including rainwater, fresh surface waters, and sediment pore waters.

Comparative efficacy of a recombinant feline interferon omega in refractory cases of calicivirus-positive cats with caudal stomatitis: a randomised, multi-centre, controlled, double-blind study in 39 cats.

Chronic caudal stomatitis with alveolar/buccal mucositis in calicivirus-positive cats is the most severe presentation of feline chronic gingivostomatitis. Refractory cases are helped by antibiotic and anti-inflammatory treatments often including glucocorticoids. In order to evaluate the comparative efficacy of oromucosal administration of recombinant feline interferon omega (rFeIFN-ω) versus oral administration of glucocorticoids, a randomised, multi-centre, controlled, double-blind study was performed in 39 cats. The progression of behavioural, clinical and lesional scores was assessed over 90 days. Daily oromucosal treatment with 0.1 MU of rFeIFN-ω was associated with a significant improvement of clinical lesions (caudal stomatitis and alveolar/buccal mucositis) and a decrease of pain scores from D0 to D90. Although no such statistical improvement was noticed in the prednisolone group, there was, however, no significant difference between the two groups for most of the parameters, except pain at D60 and D90.

Actinomycin D inhibits initiation of DNA replication in mammalian cells.

Mammalian (Chinese hamster ovary) cells were synchronized in the division cycle and blocked at the beginning of S phase with fluorodeoxyuridine. Traces of thymidine in the medium allowed cells to enter S phase and initiate DNA replication at some origins. For many hours after the traces of thymidine were depleted new sites for DNA replication accumulated in a small fraction of the DNA. However, these potential origins became active in bidirectional replication only when cells were released by adding [3H]thymidine to the medium. Lysis at 37 degrees C released most of the pulse-labeled DNA as linear double-stranded segments larger than Okazaki fragments and smaller than the unreplicated parental DNA. Release of the newly replicated DNA involves breakage of the template chains at or near each fork. The size of the fragments increased linearly with time of pulse labeling, but the efficiency of their release decreased. The excision could be prevented by lysis at 0 degrees C. When cells were treated with actinomycin D for 3--5 min before release, the new origins failed to function, but chain growth continued from those sites at which initiation had taken place before depletion of thymidine. We interpret these results to indicate that initiation at origins requires an actinomycin D-sensitive step, presumably RNA transcription, while chain elongation, which involves the formation of Okazaki pieces, is relatively insensitive to actinomycin D during growth over long intervals.