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A first-generation amperometric galactose biosensor has been systematically developed utilizing layer-by-layer (LbL) construction of xerogels, polymers, and carbon nanotubes toward a greater fundamental understanding of sensor design with these materials and the potential development of a more efficient galactosemia diagnostic tool for clinical application. The effect of several parameters (xerogel silane precursor, buffer pH, enzyme concentration, drying time and the inclusion of a polyurethane (PU) outer layer) on galactose sensitivity were investigated with the critical nature of xerogel selection being demonstrated. Xerogels formed from silanes with medium, aliphatic side chains were shown to exhibit significant enhancements in sensitivity with the addition of PU due to decreased enzyme leaching. Semi-permeable membranes of diaminobenzene and resorcinol copolymer and Nafion were used for selective discrimination against interferent species and the accompanying loss of sensitivity with adding layers was countered using functionalized, single-walled carbon nanotubes (CNTs). Optimized sensor performance included effective galactose sensitivity (0.037 μA/mM) across a useful diagnostic concentration range (0.5 mM to 7 mM), fast response time (~30 s), and low limits of detection (~80 μM) comparable to literature reports on galactose sensors. Additional modification with anionic polymer layers and/or nanoparticles allowed for galactose detection in blood serum samples and additional selectivity effectiveness.

Introduction: This is a review of elective rectal cancer surgery during 1993-1999 at a single district general hospital to investigate the variables that affected the care of these patients., Patients and Methods: A retrospective study of patients presenting with rectal adenocarcinoma to a district general hospital where total mesorectal excision was practiced over a 7-year period was performed to identify factors associated with complications, death and disease recurrence., Results: Sixty-one patients developed a total of 89 complications and 30-day mortality was 8.3%. Overall, 81% of all resections and 86% of potentially curative resections were free of tumour at the circumferential resection margin. A positive circumferential resection margin and 30-day mortality were both associated with increased postoperative blood transfusion volume. Twenty-nine recurrences were detected during the follow-up period (mean, 21.7 months) and circumferential margin involvement by tumour, Dukes' stage, pre-operative functional status (ASA grade) and length of hospital stay correlated with disease-free survival., Conclusions: Surgical outcomes in lower volume hospitals are comparable with those reported by larger centres.