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Biomedical subjects

R Waring

Publications and source records attributed to R Waring.

8 recordsLinked to original sources
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

Genetic factors influencing the outcome of early arthritis--the role of sulphoxidation status.

A minority of individuals have an impaired ability to oxidize sulphur. An increased prevalence of this poor S-oxidation capacity has been observed in patients with established rheumatoid arthritis (RA). The role of this enzyme system in the development of disease was studied by testing the S-oxidation capacity of 54 patients with recent onset symmetrical poly-arthritis, who were followed up at 1 and 4 years. Those patients with persistent disease at 1 year had a prevalence of poor S-oxidation of 69%. At 4 years 74% of those with a diagnosis of RA were poor S-oxidizers compared to 31% of those who were asymptomatic (P less than 0.01). A defective ability to oxidize sulphur appears to predispose to persistent clinical disease.

Arthritis, Rheumatoid↗
PubMed1992

Increased prevalence of poor sulphoxidation in patients with rheumatoid arthritis: effect of changes in the acute phase response and second line drug treatment.

A minority of normal subjects have an impaired ability to oxidise sulphur, which is associated with an increased risk of side effects when they receive sulphur containing drugs. In 114 patients with rheumatoid arthritis a greatly increased prevalence of poor sulphoxidation was found in 82 (72%) patients compared with 70/200 (35%) healthy controls, 45/121 (37%) controls matched for age, and 4/35 (11%) of the normal aged general population. In a longitudinal study of 37 patients there was no significant alteration in sulphoxidation status after the introduction of a second line drug or with marked changes in the acute phase response. It seems, therefore, that the poor sulphoxidation status in patients with RA is not an epiphenomenon and may be an important factor in determining the clinical features of rheumatoid disease.

Acute-Phase Reaction↗
PubMed1991

Metabolic biomarkers of Parkinson's disease.

Enzymic systems involved with metabolism of foreign chemicals, xenobiotics, have been studied in Parkinson's disease. Enzymes involved with sulphur oxidation and methylation are under-active. Cysteine levels are high and sulphate levels low. Differences in the activity of the enzyme monoamine oxidase-B are evident. Pathways involved with N-methylation of pyridines are different from controls leading to a rise in potentially toxic N-methylated derivatives.

Carbocysteine↗
PubMed1991

Xenobiotic enzyme profiles and Parkinson's disease.

Xenobiotic enzymic systems have been studied in Parkinson's disease. Platelet monoamine oxidase-B activity is increased by the use of phenylethylamine but decreased by the use of dopamine as substrate. Enzymes involved with sulfur oxidation and methylation are underactive.

Animals↗
PubMed1990

The relationship of sulfoxidation status to efficacy and toxicity of penicillamine in the treatment of rheumatoid arthritis.

Penicillamine shows some structural similarities to carbocysteine. The ability to oxidize carbocysteine, i.e., the sulfoxidation status, shows a bimodal distribution in the general population. In this study, sulfoxidation status was determined in 50 of 60 rheumatoid arthritis patients receiving penicillamine. We found that poor sulfoxidation status, compared with good sulfoxidation status, was associated with a 3.9 times higher incidence of toxicity.

Arthritis, Rheumatoid↗