Gas chromatographic determination of midazolam in low-volume plasma samples

A gas chromatographic method for the sensitive determination of midazolam in plasma volumes as low as 40 μl was developed, utilizing clinazolam as the internal standard. After liquid-liquid extraction at basic pH into 1-chlorobutane-dichloromethane (96:4) a 2- to 4-μl portion of the reconstituted extract was injected under electronic pressure control onto a 12 m × 0.2 mm I.D. methyl silicone capillary column, and was exposed to a three-step temperature program from 120 to 310°C, to separate the analytes from the plasma constituents. The compound of interest was identified and quantified by means of a mass-selective detector. The assay was linear from 10 to 500 ng/ml using 40 μl of plasma (limit of quantification: 10 ng/ml) and was linear from 0.25 to 100 ng/ml using 500 μl of plasma (limit of quantification: 0.25 ng/ml). The intra-day precision for the 40-μl aliquots varied from 2.2 to 6.6%, the corresponding accuracy from −7.4 to −4.4%; the inter-day precision ranged from 5 to 7.2% and the corresponding accuracy from −7.2 to −5.1%.     

Genetic Diversity of <Emphasis Type="Italic">Pasteurella dagmatis</Emphasis> as Assessed by Analysis of the 16S rRNA and <Emphasis Type="Italic">rpoB</Emphasis> Gene Sequences

A total of 16 Pasteurella dagmatis strains, including 11 feline and 4 canine isolates as well as one strain isolated from a tiger, were analyzed using partial 16S rRNA and rpoB gene sequence comparison. Phylogenetic studies based on both genes revealed that the population of P. dagmatis recovered from cats in Poland differs markedly from canine strains, constituting a well-separated cluster within Pasteurella sensu stricto species group. The isolate from a tiger seems to represent yet another evolutionary lineage within P. dagmatis.