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W S Morrison

Publications and source records attributed to W S Morrison.

4 recordsLinked to original sources

A survey of radiographs obtained at the initial dental examination and patient selection criteria for bitewings at recall.

This paper reports the results of a 1980 survey of a 27% simple random sample of all practicing dentists in North Carolina. The objective of the survey was to establish current practice standards regarding panoramic, full-mouth series, and bitewing radiographs. A total of 414 dentists (76.2% of those surveyed) responded. A questionnaire recorded demographic data on the dentists, age-specific prevalence data on the type of radiograph most often done at a patient's initial visit, and prevalence of radiographs based on need as perceived by the dentist and assessed separately for a variety of patient characteristics (age, oral hygiene, caries activity, fluoride treatment, and systemic medical problems). Results of the survey of a subset of 338 dentists in general practice showed the median age to be 40 with a median length of experience of 13 years. At an initial visit, for patients younger than 12, bitewing radiographs only were most commonly taken; for patients older than 12, bitewings plus a panoramic radiograph were taken. Full-mouth series plus bitewings were rarely performed among patients younger than 6 years (2.1% of the time), but were more commonly performed as patients aged (29.0% for patients aged 40 and older). A variety of patient characteristics were considered for their impact on the need for bitewing radiographs on recall. Caries activity was ranked most important by the general dentist, followed by oral hygiene and periodontal activity.

Adolescent↗

Finding a fracture.

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Diagnosis, Differential↗

Maleylacetone cis-trans-isomerase: affinity chromatography on glutathione-bound sepharose. Two-substrate-binding sequence from inhibition patterns.

Maleylacetone cis-trans-isomerase isolated from Vibrio 01 binds glutathione strongly; Km = 1.4 X 10(-4) M. Oxidized glutathione and S-methylglutathione are competitive inhibitors, KI = 9.4 X 10(-4) and 1.2 X 10(-3) M, respectively. Based on these interactions, three different glutathione-bound agarose affinity adsorbents were synthesized and tested. Affinity chromatography of the isomerase with one of these affords 70- to 100-fold purifications. In separate syntheses, portions of the affinity arm were prepared and examined as to their inhibitory properties in the enzyme-catalyzed reaction. The fragment, containing glutathione bound through its sulfur to the carbon chain, is a powerful competitive inhibitor for glutathione (KI = 6 X 10(-5) M). The results described suggest that the isomerase binds glutathione through the backbone of the tripeptide and that the thiol group is required for activity. The initial velocity patterns of the enzyme-catalyzed reaction resulting from simultaneous variation of glutathione and maleylacetone concentrations were examined in the absence and presence of inhibitors resembling glutathione. The observed kinetic patterns suggest an ordered sequence of binding maleylacetone first followed by glutathione.

Binding Sites↗