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P Wordsworth

Publications and source records attributed to P Wordsworth.

At least 73 records · Page 4Linked to original sources
PubMed1993

Analysis of a T-cell receptor V beta segment implicated in susceptibility to rheumatoid arthritis: V beta 2 germline polymorphism does not encode susceptibility.

OBJECTIVES: The assessment of allelic polymorphism of the T cell receptor gene segment, TCRBV2S1, in rheumatoid arthritis. METHODS: A total of 136 patients with rheumatoid arthritis (RA) (ACR criteria) and 150 controls were TCRBV2S1 genotyped using a nested PCR amplification strategy followed by single-strand conformation polymorphism (SSCP) analysis. RESULTS: The SSCP typing method detected two previously unknown alleles of the TCRBV2S1 gene segment. The TCRBV2S1 allele, genotype and inferred phenotype frequencies were similar in the RA patients and controls. No differences were apparent after the RA patients had been partitioned according to their HLA-DR genotypes. CONCLUSIONS: SSCP analysis is a rapid and efficient method of typing T cell receptor germline polymorphisms. Allelic polymorphism of the T cell receptor variable segment, TCRBV2S1, does not influence susceptibility to RA.

Alleles↗
PubMed1992

Production of methionyl-minus ovine growth hormone in Escherichia coli and one-step purification.

The overproduction of ovine growth hormone (oGH) in Escherichia coli is described, achieved in part by alteration of the codon usage for nine of the first 15 amino acids (aa) of the mature hormone. Recombinant oGH (re-oGH), representing 12% of the total cellular protein, was isolated from inclusion bodies by solubilisation using the cationic surfactant cetyltrimethylammonium chloride (CTAC). The hormone was refolded and subsequently purified to greater than 95% homogeneity in a single step using preparative reverse phase high performance liquid chromatography. The aa sequence analysis revealed that the N-terminus of the E. coli-derived polypeptide was identical to that of pituitary-derived oGH, and re-oGH displayed potent somatotropic activity in vivo.

Amino Acid Sequence↗
PubMed1992

Genetically determined factors as predictors of radiological change in patients with early symmetrical arthritis.

OBJECTIVE: To determine whether genetic factors associated with established rheumatoid arthritis could, in combination with rheumatoid factor, predict the development of radiological erosions in patients with early symmetrical (rheumatoid-like) arthritis. DESIGN: Prospective study. SETTING: Teaching hospital, early arthritis clinic. SUBJECTS: Forty nine patients with symmetrical polyarthritis attending the early arthritis clinic. MAIN OUTCOME MEASURES: Conserved sequence of DR beta third allelic hypervariable region, sulphoxidation capacity, rheumatoid factor, and development of radiologically determined bone erosions. RESULTS: None of the 49 patients had radiological erosions at presentation but 25 developed these by four years. Patients with the conserved class II major histocompatibility complex (third allelic hypervariable of DR beta 1) genes associated with rheumatoid arthritis had a relative risk for the development of erosions of 1.9 (95% confidence interval 0.8 to 4.5). For poor sulphoxidation the risk was 2.5 (1.1 to 5.6) and for the presence of rheumatoid factor 1.8 (0.9 to 3.7). Of the 33 patients who had two or three of these risk factors, 24 developed erosions, with a relative risk of 11.6 (1.7 to 78.5) compared with only one of the 16 individuals with no or one risk factor. CONCLUSIONS: This preliminary study shows that by using these stable markers it is possible to make clinically useful predictions of outcome in patients with early symmetrical inflammatory arthritis.

Acute-Phase Reaction↗
PubMed1992

Rheumatoid arthritis.

Rheumatoid arthritis is often considered to be an autoimmune disease in which the abnormal immunological response is triggered by an infectious agent(s) but progress towards identifying such extrinsic factors has so far been unrevealing. In contrast, the genetic component of host susceptibility is slowly becoming clearer. In particular, the nature of the HLA class II association with the disease has led to new insights into its pathogenesis and possible novel forms of therapy.

Arthritis, Rheumatoid↗
PubMed1992

HLA heterozygosity contributes to susceptibility to rheumatoid arthritis.

We have investigated the role of HLA-DR genotypes in 184 patients with severe rheumatoid arthritis (RA) and in 46 patients with Felty syndrome, to establish the relative contribution of the RA-associated subtypes of DR4 (Dw4, Dw14, and Dw15). There was an excess of DR4 homozygotes, particularly Dw4/Dw14 compound heterozygotes (relative risk [RR] 49). The risk associated with Dw4 depended on the other allele present--Dw4/DR1 (RR 21), Dw4/Dw4 (RR 15), and Dw4/DRX (RR 6). There was a significant risk from Dw4/Dw14 compared with Dw4/Dw4, both in those with severe RA (RR 2.9; P less than .02) and in those with Felty syndrome (RR 4.2; P less than .02). In contrast, in a further 63 known DR4 homozygotes with RA, not selected for severe disease, the excess of Dw4/Dw14 was much less striking (RR 1.4; not significant), suggesting that this genotype may be particularly associated with more severe disease. We also found four cases with the rare Dw4/Dw15 genotype (expected less than or equal to 0.5; P less than or equal to .02). Since the Dw4, Dw14, Dw15, and DR1 molecules have similar antigen-binding sites and since combinations of these alleles particularly predispose to severe RA, we suggest that synergistic mechanisms are involved. These could include an effect on T-cell repertoire selection.

Alleles↗
PubMed1991

Critical role for the Val/Gly86 HLA-DR beta dimorphism in autoantigen presentation to human T cells.

Helper T lymphocytes recognize fragments of foreign (or self) antigens in the peptide-binding clefts of major histocompatibility complex class II molecules; their activation is a crucial step in the induction of many immune and autoimmune responses. While studying the latter, we raised a T-cell line from the thymus of a myasthenia gravis patient against recombinant alpha subunit of the human acetylcholine receptor, the target of this autoimmune disease. The line responds to the 144-156 region of the human sequence and not to the same region of the electric fish homolog, which differs by only three residues. These CD4+ T cells recognize this epitope only in the context of HLA-DR4 class II molecules, of which the variants with Gly86 are absolutely required. Thus the naturally occurring alternatives Dw14.2 (Gly86) and Dw14.1 (Val86)--which differ only at this one position in the entire antigen-binding region--show an all-or-nothing difference in presenting activity. This dimorphism at position 86 is widespread, occurring in subtypes of DR1, DR2, DR3, DR5, and DR6 alleles as well as DR4. Since other DR4 subtypes with substitutions at positions 70-74 also fail to present this peptide, and glycine residues can be uniquely flexible, we suggest that this replacement at position 86 acts locally or at a distance by altering the conformation of the peptide-binding cleft. Such profound functional consequences for T-cell recognition as we report here may explain this example of conserved major histocompatibility complex diversity.

Adolescent↗
PubMed1991

Techniques used to define human MHC antigens: polymerase chain reaction and oligonucleotide probes.

The various HLA class II specificities, identifiable by serological or cellular typing reagents, reflect underlying polymorphisms of the constituent alpha and beta chains, encoded at several loci within the HLA-D region. Variation in these genes is concentrated in allelic hypervariable regions but can also be found elsewhere. Sequence-specific oligonucleotides (SSO) can be used to detect individual alleles with a high degree of accuracy by probing dot-blotted DNA, amplified to high copy number by the polymerase chain reaction (PCR). The classic DR specificities (DR1-DRw14) can be identified with certainty by sequential hybridization to a series of 14 SSO probes. In addition, fine resolution of specificities such as the subtypes of DR4 is possible using a combination of SSO probes and group-specific amplification in which PCR primers designed to amplify only DR4 alleles are employed. Similar methods can be applied to the typing of DQ and DP alleles even on whole blood samples which have been stored at -20 degrees C for up to 8 years. A full HLA class II type may be obtained on a large number of samples simultaneously without the need to separate and store viable lymphocytes. Thus, the sensitivity and robustiness of this technique give it major applications in the analysis of histocompatibility and disease associations, particularly in circumstances where facilities for the initial preparation and storage of samples may be limited.

Alleles↗
PubMed1991

Strong primary selection for the Dw4 subtype of DR4 accounts for the HLA-DQw7 association with Felty's syndrome.

Felty's syndrome (FS) is a rare complication of rheumatoid arthritis (RA) previously shown to be strongly associated with HLA-DR4 and less significantly with HLA-DQw7. To map more precisely the HLA locus responsible for susceptibility to FS, we have examined HLA-DR4 and DQ beta-chain polymorphisms in FS patients and controls using restriction fragment length polymorphism analysis and polymerase chain reaction amplification in conjunction with oligonucleotide probing. The increased frequency of DR4 in FS (93% vs. 32% controls) was due almost entirely to enrichment for the Dw4 subtype (88% vs. 20% controls) with a secondary increase of the Dw14 subtype. Dw10 and Dw13 subtypes of DR4 were absent from the patient group. Increase in DQw7 frequency among DR4 FS patients could be accounted for by linkage disequilibrium between Dw4 and DQw7 alleles. Whereas susceptibility to RA is strongly associated with a conserved HLA-DR beta epitope associated with several DRB1 alleles, it is primarily the Dw4 allele which is associated with progression to Felty's syndrome. The finding that amino acid sequence variation at the DR4B1 locus rather than DQB1 is associated with development of FS will have important implications for the development of novel immunotherapies which are major histocompatibility complex allele-dependent.

Amino Acids↗
PubMed1991

A limited association of generalized osteoarthritis with alleles at the type II collagen locus: COL2A1.

A significant genetic influence in osteoarthritis has been observed in the combination of Heberden's nodes and generalized osteoarthritis. We examined whether mutation in the gene encoding the major cartilage matrix protein type II collagen was responsible by comparing allele frequencies at the locus (COL2A1) in a group of 61 patients with nodal GOA with a control population and by analysing the COL2A1 genotypes of 21 affected sibling pairs. There were no significant allele differences but a slightly increased tendency over chance alone for affected siblings to have inherited the same COL2A1 alleles from their parents.

Alleles↗
PubMed1990

Consistent linkage of dominantly inherited osteogenesis imperfecta to the type I collagen loci: COL1A1 and COL1A2.

The segregation of COL1A1 and COL1A2, the two genes which encode the chains of type I collagen, was analyzed in 38 dominant osteogenesis imperfecta (OI) pedigrees by using polymorphic markers within or close to the genes. This was done in order to estimate the consistency of linkage of OI genes to these two loci. None of the 38 pedigrees showed evidence of recombination between the OI gene and both collagen loci, suggesting that the frequency of unlinked loci in the population must be low. From these results, approximate 95% confidence limits for the proportion of families linked to the type I collagen genes can be set between .91 and 1.00. This is high enough to base prenatal diagnosis of dominantly inherited OI on linkage to these genes even in families which are too small for the linkage to be independently confirmed to high levels of significance. When phenotypic features were compared with the concordant collagen locus, all eight pedigrees with Sillence OI type IV segregated with COL1A2. On the other hand, Sillence OI type I segregated with both COL1A1 (17 pedigrees) and COL1A2 (7 pedigrees). The concordant locus was uncertain in the remaining six OI type I pedigrees. Of several other features, the presence or absence of presenile hearing loss was the best predictor of the mutant locus in OI type I families, with 13 of the 17 COL1A1 segregants and none of the 7 COL1A2 segregants showing this feature.

Chromosomes, Human, Pair 17↗
PubMed1989

Genetic segregation analysis of familial mitral valve prolapse shows no linkage to fibrillar collagen genes.

Three pedigrees were identified in which mitral valve prolapse seemed to be inherited as a mendelian autosomal dominant trait. The segregation of the genes encoding the major fibrillar collagens present in valve tissue, collagens I and III, was analysed by use of restriction enzyme site variants as genetic markers. In one pedigree there was discordance between the segregation of the disease and markers for all three collagen genes. In another, there was discordance between the disease and markers for both collagen I loci. This is evidence against the disease being generally the result of mutations of the genes encoding the major fibrillar collagens.

Collagen↗
PubMed1988

Structural and segregation analysis of the type II collagen gene (COL2A1) in some heritable chondrodysplasias.

Seventy-seven persons with a variety of heritable chondrodysplasias were screened for gross rearrangements of the structural gene encoding the major cartilage collagen, collagen II. None was found. Segregation of the locus (COL2A1) was studied in 19 pedigrees using three restriction site dimorphisms (shown by PvuII, HindIII, and BamHI) and a length polymorphism as linkage markers. Discordant segregation between COL2A1 and the mutant locus was seen in pedigrees with multiple epiphyseal dysplasia, autosomal recessive spondyloepiphyseal dysplasia tarda, hypochondroplasia, pseudoachondroplasia, diaphyseal aclasis, and trichorhinophalangeal syndrome. One pedigree with diastrophic dysplasia was weakly concordant. Autosomal dominant spondyloepiphyseal dysplasia tarda and metaphyseal chondrodysplasia (type Schmid) were not informative. We conclude that mutations of the collagen II gene are not a common feature of the heritable chondrodysplasias. Since the chondrocyte binding protein, chondrocalcin, is also encoded at COL2A1 our conclusions apply equally to this gene.

Calcium-Binding Proteins↗
PubMed1987

Joint mobility with particular reference to racial variation and inherited connective tissue disorders.

Joint mobility scores were compared in 248 normal English Caucasian males and females between the ages of 8 and 70 years. The results were contrasted with those in a group of normal Asian Indians and patients suffering from a variety of inherited disorders including Type II Ehlers-Danlos syndrome (EDS), Type I osteogenesis imperfecta (OI), Marfan syndrome, generalized osteoarthritis (GOA), achondroplasia and pseudoachondroplasia. The first-degree relatives of ten subjects with severe or lethal OI were also examined. Asian Indians were significantly more mobile than English Caucasians. Males and females with EDS were hypermobile but only the females with OI and the female relatives of those with severe or lethal OI showed excess joint laxity. Patients with pseudoachondroplasia exhibited a grosser type of joint laxity than other subjects while those with GOA represented a relatively stiff group. No evidence was found to support the view that hypermobility is associated with particular length variants at the Type II collagen structural gene locus (COL2A1).

Achondroplasia↗
PubMed1986

Osteogenesis imperfecta is linked to both type I collagen structural genes.

The segregation of the two type I collagen structural gene loci COL1A1 and COL1A2 was analysed in eleven osteogenesis imperfecta pedigrees by means of restriction-site variants at, or close to, these loci. In each case, the OI gene was inherited with one or other collagen locus. As well as identifying the common OI loci the result of this analysis sets limits on the frequency of a third locus and lays the foundation for a widely available antenatal diagnostic test.

Chromosome Mapping↗
PubMed1986

Evidence against the structural gene encoding type II collagen (COL2A1) as the mutant locus in achondroplasia.

The structure of the locus encoding the major cartilage collagen gene (COL2A1) was studied in a total of 19 cases of achondroplasia. No gross rearrangements were seen. The segregation of COL2A1 was examined in three affected kindreds using restriction site and length variants as genetic markers. In two kindreds discordant segregation between the achondroplasia and COL2A1 loci was demonstrated. Paternity/maternity was confirmed using a 'minisatellite' core sequence probe which reveals cross hybridising polymorphic loci.

Achondroplasia↗