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Biomedical subjects

D Duffy

Publications and source records attributed to D Duffy.

6 recordsLinked to original sources

Rheumatoid arthritis in twins: a study of aetiopathogenesis based on the Australian Twin Registry.

The 1980 cohort of the Australian Twin Registry contains 3808 pairs of twins, 258 of whom self reported a diagnosis of rheumatoid arthritis (RA) in one or both subjects. Seventy two pairs were lost to follow up by 1990. The remaining 186 pairs received a self administered questionnaire, followed, if necessary, by telephone interviews to them, their general practitioners, and their specialists. Twenty discordant and three concordant pairs of twins were verified as having RA. The prevalence of RA in this sample was 0.40%. There was an 89% false positive rate for the self reported diagnosis of RA. Pairwise concordance percentages for RA were as follows: monozygotic 21% (95% confidence interval (CI) = 6 to 44), dizygotic 0% (95% CI = 0 to 25). It was concluded that: (a) there is a high false positive rate in self reporting RA; (b) the prevalence of RA in Australia may be less than the 0.8-1.0% often quoted; and (c) genetic factors play some part in the aetiopathogenesis of RA but do not account entirely for its determination.

Adolescent

The medical education system in Oklahoma.

This paper provides a data base and analysis of the effectiveness of the public medical education system in Oklahoma. It provides the facts from which future decisions for Oklahoma health manpower policies might be developed.

Career Choice

Structural properties of the renal parathyroid hormone receptor: hydrodynamic analysis and protease sensitivity.

The highly specific ligand [125I]bovine (b) PTH-(1-34) and a chemical cross-linking technique were used to explore structural features of the canine renal cortical PTH receptor. Membranes isolated under conditions designed to inhibit endogenous proteolysis displayed a major 85K labeled PTH receptor moiety on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cross-linked receptors were solubilized with Lubrol-PX and partially purified by affinity chromatography on wheat germ agglutinin-agarose, and their hydrodynamic properties were assessed [Stokes radius = 7.3 +/- 0.1 nm; sedimentation coefficient = 6.4 +/- 0.2S; partial specific volume = 0.758 +/- 0.01 ml/g; frictional coefficient = 1.68 +/- 0.04; mol wt (Mr) = 216,000 +/- 14,000]. Corrections for detergent binding and for the presence of carbohydrate yielded an estimated Mr of 166,000 +/- 11,000 for the solubilized PTH receptor. Thus, the renal PTH receptor is oligomeric, with a Mr approximating that expected of a homodimer of 85K subunits. Peptide-mapping experiments revealed the presence within the 85K PTH receptor subunit of at least two major regions sensitive to proteolytic attack. Both elastase and an endogenous renal protease(s) cleaved the PTH receptor to a 70K form that is fully functional with respect to high affinity, guanyl nucleotide-sensitive PTH binding. Cleavage in a second domain by elastase, S. aureus V8 protease, or chymotrypsin generated a 50K labeled PTH receptor fragment. Cleavage at this second site was prevented by prior occupancy of the receptor with [125I]bPTH-(1-34), suggesting that this domain may be functionally important. Reduction of receptor disulfide bonds with dithiothreitol and beta-mercaptoethanol released a low Mr (less than or equal to 14K) labeled PTH receptor component, similar treatment of renal membranes abolished specific PTH binding, indicating that an intact disulfide bond(s) is essential for receptor function. These results provide new insights into the structural basis of PTH receptor function.

Animals

Compromised T-cell regulatory functions during anuran metamorphosis: the role of corticosteroids.

Glucocorticoid receptor concentrations, which are undetectable before metamorphosis, increase to a maximum during the metamorphic period and decline to toadlet levels thereafter. The generation of a high concentration of receptors, imparting enhanced glucocorticoid sensitivity particularly to the lymphoid tissues of metamorphic larvae suggests the possibility that increasing endogenous levels could be responsible for the compromised T-cell functions which have been described for these stages of development (Ruben et al, 1985a).

Adrenal Cortex Hormones