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Biomedical subjects

R Clarkson

Publications and source records attributed to R Clarkson.

5 recordsLinked to original sources
PubMed1991

Immunogenetic heterogeneity in rheumatoid disease as illustrated by different MHC associations (DQ, Dw and C4) in articular and extra-articular subsets.

Genetic variants at DRB1 (Dw subtypes), DQB, and C4 loci were compared in rheumatoid disease subjects with or without the extra-articular feature of Felty's syndrome or major vasculitis. DR4 positive subjects with rheumatoid arthritis alone showed no preferential associations with DQB or Dw variants or with C4 null alleles. Felty's subjects showed associations with the DQB encoded DQw7 allele and with the C4B null allele but no preferential associations with any Dw subtype of DR4. By contrast DR4 +ve rheumatoid-vasculitic subjects showed associations with the Dw14 as well as with DQw7 and the C4A null allele. These different MHC associations in different clinical disease subsets show that rheumatoid disease is immunogenetically heterogeneous and suggest that MHC genes outside the DRB1 locus may also influence susceptibility or modify expression of the rheumatoid disease process.

Alleles↗
PubMed1990

DQw7 and the C4B null allele in rheumatoid arthritis and Felty's syndrome.

DQ beta and C4 null alleles have been defined in patients with rheumatoid arthritis, Felty's syndrome, and in control subjects. Comparison of DR4 positive subjects shows that rheumatoid disease without extra-articular features has no preferential associations with either DQ beta or C4 null variants. In Felty's syndrome there are significant associations with both the class II major histocompatibility complex (MHC) DQw7 allele (86% of DR4 positive patients with Felty's syndrome and 53% of DR4 positive controls) and the class III MHC C4B null allele (50% of patients with Felty's syndrome and 20% of DR4 positive controls). DQw7 and the C4B null allele are in linkage disequilibrium and the B44-Bf *S-C4A*3-C4B*Q0-DR4-DQw7 haplotype accounts for five of 24 DR4 positive haplotypes assigned in subjects with Felty's syndrome. The results were not accounted for by articular disease severity and suggest that articular and extra-articular forms of rheumatoid disease may be immunogenetically heterogeneous.

Alleles↗
PubMed1990

Studies of a C2 DNA polymorphism in RA, Felty's and normal subjects.

A restriction fragment length polymorphism at the C2 locus was studied in rheumatoid arthritis (RA), Felty's and control subjects. No association was found between any C2 variant and either RA itself or within the rheumatoid population with Felty's syndrome. The C2 DNA polymorphism can be used to subdivide Bf*S- as well as Bf*F-bearing haplotypes. The 2.65-kb C2 DNA allele showed allelic association with HLA-B44 and C4B*Q0 and may help to further characterize the haplotype B44-Bf*S-C4A*3-C4B*Q0-DR4, which has previously been described in Felty's syndrome.

Alleles↗
PubMed1975

Molecule--receptor specificity.

The specificity of binding between small molecules and macromolecular receptors may be studied by comparing theoretically calculated conformational potential energy surfaces of a series of chemically similar molecules which have a range of receptor binding energies and biological activities. In this way essential requirements for binding may be highlighted, including the necessity of the small molecule adopting, or passing through, conformations which are not at energy minima and not found either in the solid state or in aqueous solution. In particular the conformational demands of the adrenergic beta-receptor and histamine H1 receptor are considered.

Animals↗