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Biomedical subjects

A Wardlaw

Publications and source records attributed to A Wardlaw.

11 recordsLinked to original sources
PubMed2000

Comparative metal content profiling of parasitic helminths by electron paramagnetic resonance spectrometry: significance for metalloprotein content.

Variation in co-ordination geometries of metal ions bound to proteins imposes electronic states different from free (hydrated) ions in solution. Electron paramagnetic resonance spectroscopy has been used to analyse a selection of parasitic helminths for metal content as an initial step to determination of metallo-enzymes in their ES products under immune stress conditions. Characteristic paramagnetic resonance spectroscopy spectra show clear evidence for the presence of iron, copper, and manganese centres and in the selected parasites. The metals ions are identified as protein-bound as distinct from free metal ions present in aqueous solution, and distinguishable from parasite dietary components derived from host sources. Indication is given that superoxide dismutases may, in part, account for the metal ions observed. The use of electron paramagnetic resonance spectroscopy to identify specific protein-bound metals without prior isolation of the suspected protein is here applied.

Animals↗
PubMed1999

Cu/Zn superoxide dismutase in excretory-secretory products of the human hookworm Necator americanus. An electron paramagnetic spectrometry study.

EPR spectrometry was used to investigate the effect of excretory/secretory product from Necator americanus on superoxide radical anions generated by xanthine/xanthine oxidase as a measure of excretory/secretory product superoxide dismutase activity. Using 1,1',5,5'-dimethylpyrollidine-N-oxide (DMPO) as a superoxide spin-trapping agent a 12-line EPR spectrum characteristic of the DMPO-OOH adduct was observed to decrease in the presence of excretory/secretory product. Superoxide dismutase activity was proportional to excretory/secretory protein concentration, was inhibited with cyanide treatment and was progressively destroyed with increasing time of heat denaturation of excretory/secretory product. Using a purpose-built chamber the superoxide dismutase activity of excretory/secretory product from live worms in culture was shown to accumulate with time to a maximum at 4 h. The electron paramagnetic resonance spectrum obtained for the frozen excretory/secretory product of N. americanus recorded at 77 K is typical of Cu(II) in a protein matrix. The results are consistent with the presence of an active Cu/Zn superoxide dismutase in excretory/secretory product from N. americanus and demonstrate a method for the unequivocal determination of the fate of superoxide anions in the presence of live worms.

Animals↗
PubMed1983

Age and weight as determinants of warfarin requirements.

A survey of patients attending anticoagulant clinics at a District General Hospital showed the maintenance dose of warfarin to increase with weight and decrease with age. A significant correlation was observed between age and weight considered together and the maintenance dose. It is proposed that consideration of age and weight may be of value when prescribing loading or starting doses of warfarin at initiation of therapy.

Age Factors↗