John Goodwyn Lewis

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CONTEXT Severe systemic infection leads to hypercortisolism. Reduced cortisol binding proteins may accentuate the free cortisol elevations seen in systemic infection. Recently, low total cortisol increments after tetracosactrin have been associated with increased mortality and hemodynamic responsiveness to exogenous hydrocortisone in septic shock (SS), a(More)
CONTEXT There is a paucity of longitudinal data on plasma and urinary cortisol levels during pregnancy using modern assays. Furthermore, conflicting data exist as to the effect of the low-dose oral contraceptive pill (OCP) on cortisol. DESIGN, SUBJECTS, AND MEASUREMENTS: We conducted a prospective longitudinal study on morning plasma cortisol (total and(More)
OBJECTIVES To develop, optimize, and validate a generalized mass action, equilibrium solution that incorporates measured concentrations of albumin as well as cortisol binding globulin (CBG) to estimate free cortisol. DESIGN AND METHODS Free cortisol was estimated by Coolens method or by cubic equilibrium equation and compared to measured free cortisol,(More)
A direct ELISA for plasma cortisol is described which is carried out in a standard 96 well microtitre plate. In this ELISA cortisol-thyroglobulin conjugate is immobilised to the microtitre plate and competes with cortisol in the standard or plasma sample for antibody binding sites. Following washing the rabbit cortisol antibody bound to immobilised cortisol(More)
Rugby union is a physically intense intermittent sport coupled with high force collisions. Each position within a team has specific requirements which are typically based on speed, size and skill. The aim of this study was to investigate the contemporary demands of each position and whether they can explain changes in psychophysiological stress. Urine and(More)
OBJECTIVE To measure and contrast maternal cortisol and corticosteroid-binding globulin (CBG) levels in pregnancies with normal outcomes, pre-eclampsia, intrauterine growth restriction (IUGR) and in gamete recipients. STUDY DESIGN Prospective study of 93 women at high risk of pre-eclampsia, including gamete recipients (n = 22) and 33 controls. Plasma(More)
Cortisol mouse monoclonal antibodies were produced and characterized. Of the four clones studied, supernatant from one clone (A2), compared with other cortisol monoclonal antibodies, showed minimal cross-reactivity to other C21 steroids and was suitable for the direct determination of cortisol in plasma by enzyme-linked immunosorbent assay using a standard(More)
The first report of steroid analysis in saliva was more than thirty years ago. Since that time its popularity has increased due to the attractiveness of non-invasive, repeated and simple stress-free sampling. It has proved a popular sampling fluid for psychobiology, sports medicine, pharmacology and paediatric studies as well as in the area of complementary(More)
A rapid, single extraction ELISA for testosterone in plasma is described, using a standard 96 well microtitre plate. Testosterone is covalently bonded to bovine thyroglobulin and passively adsorbed in guanidine hydrochloride to the ELISA plate, giving an immobilised antigen approach which simplifies subsequent assay standardisation for steroid hormone(More)
BACKGROUND In normal plasma free cortisol accounts for less than 6% of the total with 80-90% bound to corticosteroid-binding globulin (CBG) and the remainder associated albumin. However little is known about the distribution of free cortisol in plasma where CBG is inactivated or in congenital CBG deficiency. METHODS AND RESULTS Here we describe ligand(More)