Field enhanced sample injection for the CE determination of arsenic compounds using successive multiple ionic polymer layer coated capillaries

A capillary electrophoresis method using indirect UV detection has been applied to the determination of arsenate [As(V)], arsenite [As(III)], monomethylarsonic acid and dimethylarsinic acid. The arsenic species were successfully separated in a successive multiple ionic polymer layer coated capillary. On-line sample preconcentration of arsenic compounds were performed by employing field enhanced sample injection. A baseline separation was achieved in a basic background solution of 10 mM 2,6-pyridinedicarboxylic acid at pH 10.3. The precision of migration time was 1.2-2.4% RSD and peak height was 8.1-12.9% RSD. The limits of detection at a S/N ratio of 3 for the four arsenic compounds were found to be 20-70 ppb, which are comparable to other on-line preconcentration techniques. The enhancement factor was improved by 230-1,500-fold

Cell line dependence of metabolite leakage in metabolome analyses of adherent normal and cancer cell lines

Analysis of the metabolome can be sample and cell dependent. In this study, we compared two conventional pre-treatment approaches (trypsinization and cell scraping) in three adherently grown mammalian cell lines (two breast cancer cell lines MDA-MB-436, MCF-7 and an endothelial cell line—HMEC-1). We report experimental evidence, for the first time, demonstrating that metabolite leakage occurs with both treatments, and that the cell lines are differentially influenced. In addition, we examined two recently reported approaches of simultaneous quenching and extraction that showed minimal metabolome leakage. We also investigated the culture of cells on beads for rapid quenching and extraction, as a novel sample handling protocol. For metastatic breast cancer cells MDA-MB-436, the two direct quenching approaches and the bead harvesting approach showed favourable results with respect to metabolome leakage, compared to the conventional approaches. We characterised the recovery of eleven different classes of metabolites identified by gas chromatography–mass spectrometry in the cell extracts and the supernatants following quenching. Analysis of results based on metabolite classes is shown to be a useful approach aiding metabolomic interpretations. We also examined the effect of including a protein precipitation step on the metabolite classes detected. The de-proteinization step did not show significant improvement in overall recoveries. This investigation suggests that it is important to establish the level of metabolome leakage for the specific cell line investigated, irrespective of the methodology employed. Rapid approaches that combine quenching and extraction steps may be more effective in retaining valid metabolome data, with minimal metabolome leakage occurring

Perioperative surgical findings in congenital and acquired undescended testis

PURPOSE: Perioperative surgical findings in congenital and acquired undescended testis (UDT) were prospectively assessed. METHODS: We included all boys with congenital or acquired UDT who underwent orchidopexy at our hospital between January 2006 and August 2009. Perioperatively, we scored the position and volume of the testis, the insertion of the gubernaculum, the patency of the processus vaginalis, and the obtained position. RESULTS: We included 69 boys (aged 0.9-14.6 years) with 76 congenital UDT and 28 boys (aged 2.2-18.5 years) with 30 acquired UDT. In the congenital group, the testis was in intracanalicular position in 55 cases (72%), whereas in the acquired UDT group, this was in 11 cases (37%; P < .001). The insertion of the gubernaculum was at the bottom of the scrotum in 13 cases (17%) of the congenital UDT group and in 12 cases (40%) of the acquired UDT group (P < .05). The processus vaginalis was open in 63 cases (83%) of the congenital and in 9 cases (30%) of the acquired UDT group (P < .001). CONCLUSION: Compared to congenital UDT, acquired UDT are more likely to be situated in the superficial inguinal pouch, to have a normal insertion of the gubernaculums, and to have a closed processus vaginali