Microchip electrophoresis bioanalytical applications

Microchip electrophoresis (MCE) is a novel analytical technique resulting from miniaturization of capillary electrophoresis (CE) to a planar microfabricated separation device. The consequences of the transfer of CE to MCE in terms of benefits and drawbacks have been identified and commented. The strategies developed to overcome the unfavourable features of the chip with respect to the capillary are briefly described. A method for simultaneous separation of catecholamines and their cationic metabolites has been developed on the microchip. The addition of three modifiers was required to resolve all analytes. The sensitivity of on-chip amperometric detection has been improved by employing an enzyme-catalyzed reaction on the amperometric electrode, as well as by using a carbon nanotube-modified electrode. The developed analytical methodology has been successfully applied for a direct on-chip determination of catecholamines and their metabolites in a mouse brain homogenate. The feasibility of performing affinity measurements as well as isoelectric focusing on the microchip has been demonstrated and available applications of these two electrophoretic modes on a chip have been reviewed. A commercial Shimadzu microchip station has for the first time been applied for high-throughput microchip isoelectric focusing of therapeutic proteins and obtained results have been compared to conventional capillary isoelectric focusing

Polygenic burden in focal and generalized epilepsies

© The Author(s) (2019).Rare genetic variants can cause epilepsy, and genetic testing has been widely adopted for severe, paediatric-onset epilepsies. The phenotypic consequences of common genetic risk burden for epilepsies and their potential future clinical applications have not yet been determined. Using polygenic risk scores (PRS) from a European-ancestry genome-wide association study in generalized and focal epilepsy, we quantified common genetic burden in patients with generalized epilepsy (GE-PRS) or focal epilepsy (FE-PRS) from two independent non-Finnish European cohorts (Epi25 Consortium, n = 5705; Cleveland Clinic Epilepsy Center, n = 620; both compared to 20 435 controls). One Finnish-ancestry population isolate (Finnish-ancestry Epi25, n = 449; compared to 1559 controls), two European-ancestry biobanks (UK Biobank, n = 383 656; Vanderbilt biorepository, n = 49 494), and one Japaneseancestry biobank (BioBank Japan, n = 168 680) were used for additional replications. Across 8386 patients with epilepsy and 622 212 population controls, we found and replicated significantly higher GE-PRS in patients with generalized epilepsy of European-ancestry compared to patients with focal epilepsy (Epi25: P = 1.64×10-15; Cleveland: P = 2.85×10-4; Finnish-ancestry Epi25: P = 1.80×10-4) or population controls (Epi25: P = 2.35×10-70; Cleveland: P = 1.43×10-7; Finnish-ancestry Epi25: P = 3.11×10-4; UK Biobank and Vanderbilt biorepository meta-analysis: P = 7.99×10-4). FE-PRS were significantly higher in patients with focal epilepsy compared to controls in the non-Finnish, non-biobank cohorts (Epi25: P = 5.74×10-19; Cleveland: P = 1.69×10-6). European ancestry-derived PRS did not predict generalized epilepsy or focal epilepsy in Japanese-ancestry individuals. Finally, we observed a significant 4.6-fold and a 4.5-fold enrichment of patients with generalized epilepsy compared to controls in the top 0.5% highest GE-PRS of the two non-Finnish European cohorts (Epi25: P = 2.60×10-15; Cleveland: P = 1.39×10-2). We conclude that common variant risk associated with epilepsy is significantly enriched in multiple cohorts of patients with epilepsy compared to controls-in particular for generalized epilepsy. As sample sizes and PRS accuracy continue to increase with further common variant discovery, PRS could complement established clinical biomarkers and augment genetic testing for patient classification, comorbidity research, and potentially targeted treatment