Expedient liquid chromatographic method with fluorescence detection for montelukast sodium in micro-samples of plasma

This study describes an expedient assay for the analysis of the asthma medication, montelukast sodium (Singulair, MK-0476), in human plasma samples. After a simple extraction of the plasma, the drug and internal standard, quinine bisulfate, were measured by HPLC. The chromatographic system consisted of a single pump, a refrigerated autosampler, a C₈ 4-μm particle size radial compression cartridge at 40°C and a fluorescence detector with the excitation and emission wavelengths set at 350 and 400 nm, respectively. The mobile phase which was delivered at 1.0 ml/min, was prepared by adding 200 ml of 0.025 M sodium acetate, pH adjusted to 4.0 with acetic acid, to 800 ml of acetonitrile, with 50 μl triethylamine. With a run time of only 10 min per sample, this assay had an overall recovery of >97% with a detection limit of 1 ng/ml. The inter- and intra-run relative standard deviations at 0.05, 0.2 and 1.0 μg/ml were all <9.2%, while the analytical recovery at the same concentrations were within 7.7% of the amount added.     

Calibration of a fuzzy cellular automata model of urban dynamics in Saudi Arabia

An urban cellular automata model has been designed, developed and tested for the city of Riyadh in Saudi Arabia as a research project. The model uses fuzzy set theory to capture the uncertainty associated with the transition rules and employs two automated methods of calibration: a genetic algorithm and simulated annealing. This paper describes the results of the calibration process for three time periods: 1987–1997, 1997–2005 and 1987–2005, which are characterised by different patterns of urban development. Nine different scenarios have been devised to capture the effect of different primary drivers to development including transport, urban agglomeration and topography and their interactions. The results showed that the genetic algorithm produces a better calibrated model than parallel simulated annealing. The model that contains all primary drivers and all interactions produced the best performing calibrated model overall.     

Corrected sequence of the wheat plastid genome

Wheat is the most important cereal in the world in terms of acreage and productivity. We sequenced and assembled the plastid genome of one Egyptian wheat cultivar using next-generation sequence data. The size of the plastid genome is 133,873 bp, which is 672 bp smaller than the published plastid genome of “Chinese Spring” cultivar, due mainly to the presence of three sequences from the rice plastid genome. The difference in size between the previously published wheat plastid genome and the sequence reported here is due to contamination of the published genome with rice plastid DNA, most of which is present in three sequences of 332, 131 and 131 bp. The corrected plastid genome of wheat has been submitted to GenBank (accession number KJ592713) and can be used in future comparisons.     

Patterns of testicular cytology in men with primary infertility: any change since the Gulf War?

OBJECTIVE: To evaluate the patterns of testicular cytology in men with primary infertility, to compare the morphologic patterns between the periods 1990-1995, immediately after Gulf War II, and 1997-2001 and to determine whether there is a correlation between hormonal profile, testicular volume and morphologic pattern. STUDY DESIGN: Retrospective study of men with primary infertility. History, complete physical examination, hormonal assay and testicular ultrasound were evaluated. A total of 545 patients had samples for testicular cytology obtained from both testes. The patient's consent was obtained in all cases. Smears were interpreted under light microscopy after treatment with Diff-Quik. A total of 104 healthy, fertile subjects were used for comparison of the hormonal profile and testicular volume. RESULTS: The mean (+/- SD) age was 28.66 +/- 4.36 years and duration of marriage 4.4 +/- 4.36 years. There were 11.2% patients with normal cytology, 55.8% with hypospermatogenesis, 28.4% with testicular atrophy, 2.9% with Sertoli cells only and 1.7% with maturation arrest. A significant increase in hypospermatogenesis and decrease in the Sertoli cell-only pattern were noted in 1997-2001 when compared with 1990-1995. The mean left testicular volume was 10.53 +/- 5.51 mL3 in the infertile group vs. 15.2 +/- 4.97 in the fertile group (p < 0.003); right testicular volume was 10.84 +/- 4.77 vs. 15.15 +/- 5.31 (p < 0.003). The hormonal profile revealed higher luteinizing hormone and follicle-stimulating hormone levels in the infertile group vs. control group (8.53 +/- 9.03 and 16.44 +/- 19.243 vs. 6.98 +/- 4.53 and 7.37 +/- 6.63, respectively [p < 0.001]). Free testosterone was higher in the fertile group (39.69 +/- 12.76 vs. 20.28 +/- 8.5 [p < 0.000]). CONCLUSION: The majority of infertile males in our cohort had hypospermatogenesis; testicular atrophy was the next most common disorder. There was no major change in overall absolute numbers since the Gulf War. Testicular cytology by fine needle aspiration is a safe and well-tolerated complementary investigation for unexplained male infertility.