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Electrophoresis continues to be a mainstay in molecular genetic laboratories for checking, sizing and separating both PCR products, nucleic acids derived from in vivo or in vitro sources and nucleic acid-protein complexes. Many genomic and genetic applications demand high throughput, such as the checking of amplification products from many loci, from many clones, from many cell lines or from many individuals at once. These applications include microarray resource development and expression analysis, genome mapping, library and DNA bank screening, mutagenesis experiments and single nucleotide polymorphism (SNP) genotyping. PCR hardware compatible with industry standard 96 and 384 well microplates is commonplace. We have previously described a simple system for submerged horizontal 96 and 192 well polyacrylamide or agarose microplate array diagonal gel electrophoresis (MADGE) which is microplate compatible and suitable for PCR checking, SNP typing (restriction fragment length polymorphism or amplification refractory mutation system), microsatellite sizing and identification of unknown mutations. By substantial redesign of format and operations, we have derived an efficient 'dry' gel system that enables direct 96 pin manual transfer from PCR or other reactions in microplates, into 768 or 384 well gels. Combined with direct electrode contact in clamshell electrophoresis boxes which plug directly to contacts in a powered stacking frame and using 5-10 min electrophoresis times, it would be possible (given a sufficient supply of PCRs for examination) for 1 million gel tracks to be run per day for a minimal hardware investment and at minimal reagent costs. Applications of this system for PCR checking and SNP genotyping are illustrated.

We have developed a mutation-scanning approach suitable for whole population screening for unknown mutations. The method, meltMADGE, combines thermal ramp electrophoresis with MADGE to achieve suitable cost efficiency and throughput. The sensitivity was tested in blind trials using 54 amplicons representing the BRCA1 coding region and a panel of 94 unrelated family breast cancer risk consultands previously screened in a clinical diagnostic laboratory. All 10 common polymorphisms, 15/15 previously identified disease-causing mutations, and three previously untested single base changes were identified. Assays of LDLR exons 3 and 8 were validated in 460 familial hypercholesteremics and detected 8/9 known variants. We then applied the exon 3 assay in several DNA banks representing ∼8000 subjects with known cholesterol values and applied both assays in one DNA bank (n = 3600). In exon 3 we identified one previously reported moderate mutation, P84S (n = 1), also associated with moderate hypercholesteremia in this subject; an unreported silent variant, N76N (n = 1); and known severe hypercholesteremia splice mutation 313+1G→A (n = 2). Around exon 8 we identified a paucimorphism (n = 35) at the splice site 1061-8T→C (known to be in complete linkage disequilibrium with T705I) and unreported sequence variants 1186+11G→A (n = 1) and D335N G→A (n = 1). The cholesterol value for D335N was on the 96.2 percentile and for T705I, 2/35 carriers were above the 99th percentile. Thus, variants with predicted severe, moderate, and no effect were identified at the population level. In contrast with case collections, CpG mutations predominated. MeltMADGE will enable definition of the full population spectrum of rare, paucimorphic, severe, moderate (forme fruste), and silent mutations and effects.

The stiffness characteristics of plastic ankle foot orthoses (AFOs) are studied through finite element modelling and stress analysis. Particular attention is given to the modelling and prediction of non-linear AFO behaviour, which has been frequently observed in previous experimental studies but not fully addressed analytically. Both large deformation effects and material non-linearity are included in the formulation and their individual influence on results assessed. The finite element program is subsequently applied to the simulation of a series of tests designed to investigate the relation between AFO trimline location and stiffness for moderate and large rotations. Through careful consideration and identification of key modelling parameters, the developed finite element solution proves to be a reliable and effective alternative means of assessing variations of a typical plastic AFO design so that particular patient requirements could be met, in the long term.