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Biomedical subjects

E H Choy

Publications and source records attributed to E H Choy.

At least 37 records · Page 2Linked to original sources
PubMed1997

Nickel contamination of gold salts: link with gold-induced skin rash.

Intramuscular chrysotherapy is a well-established treatment for rheumatoid arthritis. Its therapeutic use has been limited by the high incidence of dermatological side-effects. The pathogenic mechanisms of these are unknown, but could include allergic reactions to gold or to nickel contaminating the gold. In order to investigate these mechanisms further, 15 patients, who developed cutaneous eruptions after chrysotherapy, were assessed using skin biopsy and lymphocyte transformation stimulated by gold and nickel salts in vitro. Chrysotherapy induced two main cutaneous eruptions: lichenoid reactions and non-specific dermatitis. Peripheral blood mononuclear cells from patients with lichenoid reaction proliferated to gold salts in vitro, while those who developed non-specific dermatitis responded mainly to nickel. Nickel was a significant contaminant of the gold preparation (sodium aurothiomalate, Myocrisin, Rhone-Poulenc Ltd), amounting to a total of 650 ng after 6 months treatment. We suggest that a significant percentage of skin reactions during chrysotherapy are due to nickel contamination of the gold preparation.

Adult↗
PubMed1997

Chronic sialadenitis in patients with nodal osteoarthritis.

Amongst the patients attending our combined oral medicine/rheumatology clinic, we have identified a subset presenting with xerostomia due to non-specific sialadenitis, who also suffer from generalized nodal osteoarthritis (NOA). We have called this combination SOX syndrome: sialadenitis, osteoarthritis and xerostomia. In this study, we have examined the characteristics of these patients clinically and histologically, and then determined the prevalence of SOX syndrome in patients with NOA compared to healthy age-matched controls. Patients were obtained from rheumatology clinics and a local old people's home. The series consisted of 35 patients with NOA and 18 age- and sex-matched controls without evidence of NOA or inflammatory rheumatic disease. There was no significant difference in age and sex between the two groups. None were on drugs known to induce xerostomia. The subjects were assessed for whole salivary, parotid saliva and lacrimal flow, autoantibodies, rheumatoid factor (RF) and erythrocyte sedimentation rate (ESR). The whole saliva flow (mean +/- 95% CI) was 0.32 +/- 0.07 ml/min for the NOA group and 0.54 +/- 0.17 ml/min for the control group. The difference is statistically significant (P < 0.05, two-tailed Student's t-test). No statistically significant difference was found in the parotid and lacrimal flow rates of NOA and controls. Nine of the 35 NOA patients had reduced whole salivary flow (normal range > 0.02 ml/min) compared with only one out of 18 in the control group (P > 0.05, chi 2 test). All NOA patients with xerostomia and reduced whole salivary flow were RF, anti-Ro and anti-La negative, and had a normal ESR. Thus, 25% of subjects with NOA had clinical and laboratory features of SOX syndrome, suggesting that this is a defined disease entity.

Adult↗
PubMed1997

Drug treatment of rheumatic diseases in the 1990s. Achievements and future developments.

There have been several advances in the therapy of arthritis. These are based on better understanding of the pathogenesis of rheumatic diseases, re-evaluation of previous therapeutic concepts such as combination therapy, and developments within biotechnology. There are 4 main areas of development, mainly involving the treatment of inflammatory synovitis. The first is with anti-inflammatory drugs, where there has been a focus on reducing gastrointestinal toxicity through the use of combination preparations such as diclofenac-misoprostol, and the introduction of drugs with more selectivity for cyclo-oxygenase-2 inhibition such as meloxicam. An additional approach has been the development of anti-inflammatory drugs such as tenidap which also control cytokine metabolism. The second area is slow-acting antirheumatic drugs with the introduction of cyclosporin as a single agent or in combination with methotrexate, the development of immunomodulating drugs such as leflunomide, and the demonstration that some antibiotics such as minocycline have slow-acting effects. The third area is the use of corticosteroids including the development of deflazacort as a bone sparing agent, the greater use of intramuscular depot steroids and the validation of low-dose oral corticosteroids in early rheumatoid arthritis. Finally, there have been advances in the biotechnology area with the demonstration that cytokine immunotherapy such as antibodies to tumour necrosis factor can rapidly improve the symptoms of rheumatoid arthritis, and that T cell immunotherapy with antibodies to the CD4 receptor may be effective in reducing synovitis. Many of these agents have not yet been introduced into clinical practice but they show the diversity of drug development and suggest the likelihood of major therapeutic benefits in the next few years.

Antirheumatic Agents↗
PubMed1996

Percentage of anti-CD4 monoclonal antibody-coated lymphocytes in the rheumatoid joint is associated with clinical improvement. Implications for the development of immunotherapeutic dosing regimens.

OBJECTIVE: We assessed the effect of a daily dosing schedule of the chimeric anti-CD4 monoclonal antibody (MAb), cM-T412, in rheumatoid arthritis (RA) patients, and compared lymphocyte changes in the peripheral blood (PB) and synovial fluid (SF) of these patients. METHODS: Twelve patients received 50 mg/day of cM-T412 for 5 days, followed by a maintenance treatment of 50 mg/week for 5 weeks (6 patients), or a retreatment course of 50 mg/day for 5 days after 5 weeks (6 patients). Paired PB and SF samples were obtained during treatment for analysis. RESULTS: Changes in lymphocyte count and coating with the MAb in PB did not reflect changes in the SF. After 5 daily treatments, the percentage of cM-T412-coated CD4+ lymphocytes in SF correlated with the degree of clinical improvement seen in patients at 2 weeks after the initiation of therapy (r = 0.75, P < 0.05). CONCLUSION: These results demonstrate the importance of antibody dosage and treatment regimen in determining clinical benefit. Our findings suggest that the percentage of cM-T412-coated CD4+ lymphocytes in SF may be a predictor of clinical outcome.

Adult↗
PubMed1996

Standardising joint assessment in rheumatoid arthritis.

Evaluating joint involvement in rheumatoid arthritis in a key clinical assessment. We investigated the extent of variation in measurement of joint swelling and tenderness and evaluated the impact of training to standardise methods. Eight observers (medical and nursing staff) examined eight rheumatoid patients for joint swelling and tenderness before and after training in clinical methods. The EULAR handbook for joint evaluation was used for training and assessments were based on the 28 joint count. There was extensive variability in both numbers of swollen and tender joints. Coefficients of variation for articular indices recorded by the 8 observers in individual patients were often high (up to a maximum of 204%), indicating considerable differences between observers. Training had an impact on the assessment of the numbers of swollen joints which increased by a mean of 32% (P < 0.05) and the number of tender joints which increased by 41% (p < 0.01). Training had only a limited impact on the variation among observers in determining the number of swollen and number of tender joints. After training, the mean coefficients of variation were still 59% for swollen joints and 65% for tender joints. These results highlight the extent of variation in clinical assessment of rheumatoid arthritis and show the advantages of training. It leads to increased sensitivity of measurement. Standardisation appears essential for clinical studies.

Analysis of Variance↗
PubMed1996

Endogenous opioid tone in patients with rheumatoid arthritis.

We have previously shown that there is deficient hypothalamic-pituitary-adrenal (HPA) responsiveness in rheumatoid arthritis (RA) patients. The basis for this deficient response is not known. The purpose of the project was to investigate whether the defective HPA response in RA patients is the result of increased endogenous opioid tone secondary to chronic pain which can suppress corticotrophin-releasing hormone (CRH) production. We conducted a double-blind placebo-controlled cross-over trial to study the effect of the opiate antagonist, naloxone, on psychometric function together with plasma adrenocorticotrophic hormone (ACTH), cortisol and prolactin. Seven RA patients with active and established disease and eight healthy controls were studied. Each received either a bolus i.v. infusion of 20 mg naloxone or normal saline. After at least 72 h, they received naloxone if they had previously received normal saline or vice versa. The pain score was statistically significantly higher at baseline in the RA group compared with controls (5.7 +/- 3.25 vs 0.35 +/- 0.21, P < 0.001). No difference was found in the other psychometric assessments throughout the study. Patients receiving normal saline did not show any significant change in cortisol or ACTH. Cortisol and ACTH showed a sharp and significant rise after naloxone treatment in both RA and normal subjects (P < 0.001 and P < 0.01), but no difference was observed between the two groups. The mean prolactin level showed no significant change in both groups after any treatment. We conclude that endogenous opioid tone does not appear to be a major contributor to the HPA defect in RA. However, the number of patients studied was small and this result will require confirmation from larger trials.

Adrenocorticotropic Hormone↗
PubMed1995

Innovative treatment approaches for rheumatoid arthritis. T-cell regulation.

There is considerable evidence to implicate T cells in the pathogenesis of rheumatoid arthritis (RA). They initiate and sustain inflammation and therefore are attractive targets for immunotherapy. Several strategies targeting T cells have been tried in RA. The use of monoclonal antibodies to deplete T cells have been used extensively but with little success. Studies have shown that T cell depleting antibodies produce profound peripheral blood lymphopenia but they are less effective in depleting lymphocytes in the joint. Since clinical efficacy is likely to depend on depleting almost all synovial lymphocytes, high doses of monoclonal antibodies would have to be given. However, the invariably severe peripheral blood lymphopenia induced by such a regimen is likely to result in profound immunosuppression. Therefore, this strategy has been abandoned and recent attempts have been made to induce tolerance in RA. In animal models of RA, treatment with high dose non-depleting anti-CD4 monoclonal antibody protects them from arthritis induced by injection of streptococcal cell wall. In addition, it leads to a state of anergy which protects the animals from arthritis induction without further treatment with anti-CD4 monoclonal antibody. This is currently being used in clinical trials of RA. Other tolerance inducing treatment strategies include T cell or T cell receptor vaccination and oral tolerance. The former is particularly difficult since the rheumatoid arthritogenic antigen and the pathogenic T cell remain unknown. The latter has shown promise in placebo controlled trials although the ideal dosage remains unknown. The mechanism of action of oral tolerance involves either immunosuppressive T cell cytokines, T cell anergy or depletion.

Animals↗
PubMed1995

The therapeutic effects of an engineered human anti-tumour necrosis factor alpha antibody (CDP571) in rheumatoid arthritis.

Pro-inflammatory cytokines such as tumour necrosis factor alpha (TNF alpha) have been implicated in the pathogenesis of rheumatoid arthritis (RA), and have therefore become therapeutic targets. An engineered human antibody, CDP571, that neutralizes human TNF alpha was administered intravenously in single doses of 0.1, 1.0 or 10 mg/kg to patients with active RA (n = 24). The effects of the antibody were compared in a double-blind fashion with those of placebo (n = 12). In an open continuation phase patients were given either 1.0 or 10 mg/kg. We found that CDP571 was well tolerated and caused reductions in markers of disease activity such as erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP): this was confirmed by a reduction in the disease activity score (DAS). There was a reduction in the number of tender joints, maximal in degree and duration after 10 mg/kg. Patients also documented a reduction of pain and relief of arthritis symptoms. The effects of 10 mg/kg CDP571 on ESR, CRP, tender joints, pain and symptom relief compared to placebo were statistically significant at weeks 1 or 2. The continuation phase, although open, confirmed both the safety and the beneficial effects of CDP571 in active RA. In conclusion CDP571, an engineered human anti-TNF alpha antibody, is well tolerated and, after a single dose of 10 mg/kg, provides improvements in symptoms, signs and serological markers of disease activity in patients with active RA.

Adolescent↗
PubMed1995

Therapeutic monoclonal antibodies.

Monoclonal antibodies have been used extensively over the last few years in clinical trials of rheumatoid arthritis (RA). Not only are they potential therapeutic agents, but they are also useful probes into the immunopathogenesis of RA. Anti-tumour necrosis factor alpha (TNF alpha) monoclonal antibodies have been shown to be clinically efficacious. Although they produced rapid disease amelioration, the duration of clinical improvement was limited to 4-6 weeks. Re-treatments were again effective but long-term studies are required to assess their therapeutic role in RA. So far, the therapeutic effects of lymphocyte-depleting antibodies have been disappointing. From the data, it is clear that synovial lymphocytes are more difficult to eliminate than peripheral blood lymphocytes and it is likely that in order to delete all synovial lymphocytes, high doses of depleting antibodies will be required which could lead to severe immunosuppression. Hence, lymphocyte depletion may not be a feasible therapeutic strategy. However, there are a number of clinical trials currently underway attempting to inhibit CD4 lymphocyte function by non-depleting antibodies. In animal models of RA, such antibodies have been shown to induce long-term disease remission. Another possibility is to combine several monoclonal antibodies in order to induce disease remission in RA. This strategy has been used in murine collagen-induced arthritis in which a combination of anti-CD4 and anti-TNF alpha monoclonal antibodies was shown to be synergistic.

Antibodies, Monoclonal↗
PubMed1995

Prognostic markers in rheumatoid arthritis and classification of antirheumatic therapies.

Rheumatoid arthritis is characterised by a generally poor outcome and high morbidity, and has a variable course. Identifying those patients most likely to have a poor prognosis is of key clinical significance. Disease outcome can be predicted from a variety of prognostic markers. Some of these are simple demographic features of the patients, and include age, disease duration, and gender. Others are more specific features of rheumatoid arthritis, including the presence of early erosive changes on plain radiographs, high rheumatoid factor titres, high levels of C-reactive protein, and high scores for disease activity. Although no single marker has adequate specificity or sensitivity to form the basis of clinical decisions, the presence of several is predictive of more severe disease. Thus, patients with early erosive damage who are seropositive for rheumatoid factor and have high levels of C-reactive protein are more likely to have a poor outcome. New markers and imaging techniques are likely to become the prognostic tools for the future. These include genetic markers, and a combination of magnetic resonance imaging and dual energy x-ray absorption scans for localised osteoporosis.

Antirheumatic Agents↗
PubMed1993

Chimaeric anti-CD4 monoclonal antibody cross-linked by monocyte Fc gamma receptor mediates apoptosis of human CD4 lymphocytes.

Previous studies have shown that murine anti-CD4 monoclonal antibody, cross-linked by rabbit anti-mouse immunoglobulin, could mediate apoptosis of murine CD4+ lymphocytes when they were stimulated by T cell receptor antibody. In this study, we have shown that the murine anti-CD4 monoclonal antibody, OKT4, can induce apoptosis in human CD4+ T cells stimulated by the recall antigen tuberculin purified protein derivative (PPD) only when cross-linked by rabbit anti-mouse immunoglobulin. The chimeric anti-CD4 monoclonal antibody, cM-T412 whose Fc fragment is human, was able to cause apoptosis without cross-linking by a second antibody. Similarly, abolition of PPD-induced proliferation of peripheral blood mononuclear cells by cM-T412 did not require cross-linking with rabbit anti-human immunoglobulin. Inhibition of proliferation by cM-T412 could be reduced by pre-treating monocytes with heat-aggregated human IgG. This suggested that monocyte Fc gamma receptors might be cross-linking the human Fc of cM-T412. Propidium iodide staining together with immunofluorescence showed that the apoptotic cells were indeed CD4+ lymphocytes. It is proposed that during treatment with cM-T412 in autoimmune disease such as rheumatoid arthritis, cM-T412-coated CD4 T cells, when they are subsequently stimulated by the unknown arthritogenic antigen, may undergo apoptotic cell death through cross-linking of cM-T412 on Fc gamma receptor-positive cells within the joint.

Animals↗
PubMed1993

Intramuscular methylprednisolone is superior to pulse oral methylprednisolone during the induction phase of chrysotherapy.

In a randomized double-blinded placebo-controlled trial, 41 patients with RA starting on i.m. sodium aurothiomalate (SAT) therapy were randomized to receive three doses of either 500 mg methylprednisolone (MP) orally and a placebo injection or 120 mg of i.m. depot methylprednisolone acetate (MPA) and oral placebo tablets at 4-weekly intervals. Disease activity was assessed by visual analogue scale (VAS) of pain, grip strength (GS), tender joint count (JC), and Health Assessment Questionnaire (HAQ). Laboratory assessment was by haemoglobin concentration (Hb) and ESR. A composite index of Disease Activity score (IDA) was constructed using all six measurements. The group receiving i.m. MPA showed greater improvement when compared with the group receiving oral MPA. These changes were statistically significant (P < 0.05) for ESR (weeks 2, 6, 8, 10, 12), VAS (week 4, 6, 8), JC (weeks 2, 4, 6, 8, 10) and HAQ (weeks 2, 8, 10). Statistically significantly (P < 0.05) greater improvement in Hb was seen throughout all time points in favour of the group treated with i.m. MPA. Using the IDA score to summarize the results, patients treated with i.m. MPA had better disease remission from weeks 2-12. In all measures, except Hb, no statistically significant difference between the two groups was seen by 16 weeks. We conclude that 120 mg i.m. depot MPA is more effective at inducing improvement in disease activity than 500 mg of oral MPA in RA patients starting on SAT therapy.

Administration, Oral↗
PubMed1992

Treatment of rheumatoid arthritis with single dose or weekly pulses of chimaeric anti-CD4 monoclonal antibody.

The aetiology of rheumatoid arthritis is unknown but CD4+ T cells are known to be involved in its pathogenesis. Because of this, anti-CD4 monoclonal antibody has been used in open studies with clinical benefit in up to 60% of patients. We have used a chimaeric anti-CD4 monoclonal antibody (cM-T412, Centocor) in a randomized, double-blinded, placebo controlled trial as treatment for rheumatoid arthritis. Nine patients with active rheumatoid arthritis resistant to traditional disease-modifying drugs were recruited. Four received an intravenous 50 mg bolus of antibody, and three received 50 mg weekly for four consecutive weeks. Two patients received placebo. Despite a marked reduction (P less than 0.001) in peripheral blood CD4+ lymphocytes, there was no significant clinical improvement in any of these patients. The decrease in CD4+ lymphocyte number lasted one week after a single 50 mg dose of cM-T412 but was more prolonged in the patients who received four infusions. CD8+ T cells, CD16+ cytotoxic cells and CD14+ monocytes showed only a transient reduction. It may be concluded that the therapeutic efficacy of anti-CD4 therapy is not directly related to CD4+ T-cell lymphopenia.

Adult↗
PubMed1992

Cellular immunity to cartilage proteoglycans: relevance to the pathogenesis of ankylosing spondylitis.

Cellular immunity to cartilage proteoglycans may be responsible for sustaining chronic inflammation in ankylosing spondylitis. This hypothesis was examined by measuring peripheral blood and synovial fluid mononuclear cell proliferation in five preparations of human cartilage proteoglycan monomer in vitro. Peripheral blood mononuclear cells from 25 patients and synovial fluid mononuclear cells from five patients were compared with those from normal and disease control subjects matched for age. No significant differences were found between the three groups. This suggests that autoimmune responses to cartilage proteoglycans are unlikely to play a significant part in the pathogenesis of ankylosing spondylitis.

Adult↗
PubMed1991

Isolated ACTH deficiency presenting with bilateral frozen shoulder.

We describe a 55-year-old female who presented with a 1-year history of tiredness, depression and painful stiff joints. The most striking clinical abnormality was bilateral frozen shoulders, local corticosteroid treatment of which provided the first diagnostic clue. She was found to have profound diminution of plasma cortisol secondary to an isolated deficiency of ACTH. There was no obvious cause for this. Steroid replacement eradicated her lethargy within 3 months and evidence of frozen shoulders resolved completely.

Adrenal Cortex Hormones↗