Optimization and validation of the direct HPLC method for the determination of moxifloxacin in plasma

Moxifloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-7-[(4aS,7aS)-octahydro-6H-pyrrolo-[3,4-b]pyridin-6-yl]-4-oxo-3-quinolinecarboxylic acid hydrochloride) is new, fourth generation fluoroquinolone with broaden spectrum of antibacterial activity. In the present work simple and rapid RP-HPLC method for the direct determination of moxifloxacin in human plasma is described. Separation of moxifloxacin from plasma components was achieved on Supelco LC-Hisep shielded hydrophobic phase column. The mobile phase consisted of acetonitrile and 0.25mol/dm(3) Na(3)PO(4) (pH 3) in a volume percent ratio (5:95, v/v) and was delivered at a rate of 1mL/min. Fluorescence detection was employed with excitation at 290nm and emission at 500nm. Ofloxacin was used as internal standard and sodium dodecylsulfate solution was used as a displacing agent. Sample preparation was simplified and involved only addition of displacing agent and internal standard and dilution with water. The separation conditions were optimized by the response surface method in two factor space, i.e. the dependence of the retention time on volume percent of acetonitrile and on pH of aqueous phase was optimized. The method was fully validated and validation parameters were: linearity range 3-1300microg/L; correlation coefficient, 0.99986; mean recovery, 92.5%; limit of quantification, 3.0microg/L and limit of detection, 1.0microg/L. Method was applied for the determination of moxifloxacin in human plasma after single or repeated oral doses of 400mg Avelox tablets. The proposed method proved to be rapid and accurate and can be successfully used in pharmacokinetic studies and routine clinical practice.     

The ion channel,TRPM2, contributes to the pathogenesis of radiodermatitis

Radiation and Environmental Biophysics - Radiodermatitis is a painful side effect for cancer patients undergoing radiotherapy. Irradiation of the skin causes inflammation and breakdown of the...     

The prevalence of smoking among Croatian hospitalized coronary heart disease patients

The aim of this paper was to investigate the prevalence of smoking using selected anthropometric variables in a sample of hospitalized coronary heart disease (CHD) patients in Croatia (N = 1,298). A total of 444 subjects (34.6%) were non-smokers, 548 (42.6%) were smokers and 293 (22.8%) were ex-smokers. Men, on average, smoked more cigarettes per day than women (22.62 vs. 19.84 cigarettes, p < 0.001) and they also had bigger index "pack-years" than women (36.96 vs. 33.91, p = 0.024). Men were more often smokers and ex-smokers than women (47.4% vs. 30.8% for smokers and 25.0% vs. 22.8% for ex-smokers, p < 0.001). In this study a high prevalence of smoking was found among CHD patients in Croatia. Unless it is decreased, it can be expected that CHD patients in Croatia will continue to experience adverse effects more often than other CHD patients in the rest of Europe.     

Arsenic in Agricultural Soils of a Historically Mined and Industrial Region of Southern Serbia and Northern Kosovo: Bioavailability and Uptake by Plants Species Zea mays L. and Solanum tuberosum L.

This article reports the results of a study focused on the presence and bioavailability of arsenic in agricultural soil in the mining and industrial regions of northern Kosovo and southern Serbia, as well as uptake and bioaccumulation of arsenic in two commonly cultivated plant species (Zea mays L. and Solanum tuberosum L.). This area was one of the most important mining districts in Europe. The collected soil samples were subjected to a modified BCR three-step sequential extraction procedure in order to investigate the chemical partitioning of arsenic in the soils. The general distribution of arsenic in various fractions was: exchangeable < reducible < oxidizable fractions. Highest concentrations of total arsenic in soil were found close to industrial facilities and tailing ponds. In addition, fluvisols were significantly more enriched with arsenic than soils at a distance from the river flows. The edible parts of the plant specimen showed different As contents, suggesting that these plant species have different propensities for the uptake and bioaccumulation of arsenic from soil.     

Genetic diversity and population structure of Culex modestus across Europe: does recent appearance in the United Kingdom reveal a tendency for geographical spread?

In mainland Europe, the mosquito species Culex modestus Ficalbi (1890) is a bridge vector for West Nile virus (WNV) from its natural bird-mosquito cycle to mammals. The present study assessed the genetic diversity of Cx. modestus, as well as related Culex species, using the mitochondrial COI DNA barcoding region and compared this with the population structure across Europe. A haplotype network was mapped to determine genealogical relationships among specimens. The intraspecific genetic diversity within individual Culex species was below 2%, whereas the interspecific genetic divergence varied from 2.99% to 13.74%. In total, 76 haplotypes were identified among 198 sequences. A median-joining network determined from 198 COI sequences identified two major lineages that were separated by at least four mutation steps. A high level of intraspecific genetic diversity was not detected in Cx. modestus in samples submitted from different European populations, which indicates that morphologically identified specimens represent a single species and not a species complex. Therefore, it is deduced that different populations of Cx. modestus will show a similar potential to transmit WNV, lending support to concerns that the population present in southeast England represents a risk of transmission to humans.     

Diversity of halophilic archaea in the crystallizers of an Adriatic solar saltern

Haloarchaeal diversity in the crystallizers of Adriatic Secovlje salterns was investigated using gene fragments encoding 16S rRNA and bacteriorhodopsin as molecular markers. Screening of 180 clones from five gene libraries constructed for each gene targeted revealed 15 different 16S rRNA and 10 different bacteriorhodopsin phylotypes, indicating higher haloarchaeal diversity than previously reported in such hypersaline environments. Furthermore, results of rarefaction analysis indicated that analysis of an increasing number of clones would have revealed additional diversity. Finally, most sequences from the crystallizers grouped within the Halorubrum branch, whereas square-shaped 'Haloquadratum' relatives, repeatedly reported to dominate crystallizer communities, were rare. Presence of such special and diverse haloarchaeal community could be attributed to the Secovlje salterns rare continuous short-cycling salt production mechanism.     

Agrobacterium rhizogenes-mediated transformation and plant regeneration of four Gentiana species

Shoots of micropropagated Gentiana acaulis, G. cruciata, G. lutea, and G. purpurea were inoculated with suspensions of Agrobacterium rhizogenes cells, strains ATCC 15834 or A4M70GUS. Adventitious roots appeared at the sites of inoculation in all 4 species. Root tips were excised and cultured on growth regulator-free media for 2-6 years. They exhibited very high branching and plagiotropism. Spontaneous bud initiation occurred in roots of G. cruciata. Roots of G. lutea, G. acaulis and G. purpurea were cultured on media with high kinetin concentration, which induced the formation of friable callus tissues. Only in G. purpurea were these calluses organogenic. Regenerated shoots of G. cruciata and G. purpurea gave rise to plants, that displayed the typical phenotypes of A. rhizogenes-transformed plants: short internodes and rolled leaves. In the roots of G. acaulis and G. cruciata, transformed with A. rhizogenes A4M70GUS, a positive reaction with X-gluc indicated the activity of β-glucuronidase. The DNA extracted from hairy roots and from the roots of transgenic plants hybridized with the appropriate genomic probes in Southern blotting. This is taken as evidence of the stable genetic transformation in the 4 Gentiana species. This revised version was published online in June 2006 with corrections to the Cover Date.     

Developmental History Provides a Roadmap for the Emergence of Tumor Plasticity

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Determination of trace elements in standard reference materials by the ko-standardization method

Biological Trace Element Research - The ko-standardization method is suitable for routine multielement determinations by reactor neutron activation analysis (NAA). Investigation of NIST standard...