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Biomedical subjects

P Maddison

Publications and source records attributed to P Maddison.

At least 19 recordsLinked to original sources
PubMed2005

Treatment for Lambert-Eaton myasthenic syndrome.

BACKGROUND: Lambert-Eaton myasthenic syndrome is an autoimmune presynaptic disorder of neuromuscular transmission. Treatments attempt to overcome the harmful autoimmune process, or to improve residual neuromuscular transmission, in order to reverse muscle weakness. OBJECTIVES: The objective was to examine the efficacy of treatment in Lambert-Eaton myasthenic syndrome. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group trials register (December 2004), MEDLINE (January 1966 to December 2004) and EMBASE (January 1980 to December 2004), and checked bibliographies and contacted authors to identify additional published or unpublished data. SELECTION CRITERIA: All randomised or quasi-randomised trials of adults and children with a diagnosis of Lambert-Eaton myasthenic syndrome, with or without small-cell lung cancer, receiving any form of pharmacological or physical treatment. The primary outcome measure was change in muscle strength scale score (Quantitative Myasthenia Gravis score), or limb muscle strength measured by myometry. The secondary outcome measure was improvement in the mean amplitude of the resting compound muscle action potentials. The mean amplitude used was the mean of all muscles tested. DATA COLLECTION AND ANALYSIS: We identified three randomised controlled trials. MAIN RESULTS: Two controlled trials of the effects of 3,4-diaminopyridine compared with placebo in a total of 38 patients with Lambert-Eaton myasthenic syndrome were eligible, one of which was of crossover design. A third crossover trial compared intravenous immunoglobulin treatment to placebo in nine patients. Two trials of 3,4-diaminopyridine reported a significant improvement in muscle strength score, or myometric limb measurement following treatment, and a significant improvement in resting compound muscle action potential amplitude following 3,4-diaminopyridine, compared with placebo.A meta-analysis of the primary endpoint results was not possible because of marked differences in primary outcome measures. However, a meta-analysis of the secondary endpoint was possible. The overall weighted mean difference was 1.80 mV (95% confidence interval 0.82 to 2.78), favouring treatment.A crossover trial reported a significant improvement in myometric limb strength and a non-significant improvement in change in the mean resting compound muscle action potential amplitude when patients received intravenous immunoglobulin compared to placebo infusions. Clinical improvement lasted for up to eight weeks. AUTHORS' CONCLUSIONS: Limited evidence from randomised controlled trials showed that either 3,4-diaminopyridine or intravenous immunoglobulin improved muscle strength scores and compound muscle action potential amplitudes in patients with Lambert-Eaton myasthenic syndrome. There are insufficient data at present to quantify this treatment effect. Other possible treatments have not been tested in randomised controlled trials.

4-Aminopyridine↗
PubMed2005

BILAG 2004. Development and initial validation of an updated version of the British Isles Lupus Assessment Group's disease activity index for patients with systemic lupus erythematosus.

OBJECTIVE: To devise a more discriminating version of the British Isles Lupus Assessment Group (BILAG) disease activity index and to show that it is reliable. METHODS: A nominal consensus approach was undertaken by members of BILAG to update and improve the BILAG lupus disease activity index. The index has been revised following intense consultations over a 1-yr period. It has been assessed in two real-patient exercises. These involved patients with diverse clinical features of SLE, including gastrointestinal, hepatic and ophthalmic problems, which the earlier versions of the index did not fully take into account. Reliability in terms of the ability to differentiate patients was assessed by calculating intraclass correlation coefficients. The level of agreement between physicians was determined by calculating the ratio of estimates of the standard error (SE) attributable to the physicians to the SE attributable to the patients. RESULTS: Good reliability and high levels of physician agreement were observed in one or both exercises in the constitutional, mucocutaneous, neurological, cardiorespiratory, renal, ophthalmic and haematological systems. In contrast, the musculoskeletal system did not score as well, although providing more clear-cut glossary definitions should greatly improve the situation. CONCLUSIONS: Some significant changes in the BILAG disease activity index to assess patients with SLE are proposed. The process of demonstrating validity and reliability has started with these two exercises assessing real patients. Further validation studies are under way. BILAG 2004 is likely to be valuable in clinical trials assessing new therapies for the treatment of SLE, as it provides a more comprehensive system-based disease activity measure than has been available previously.

Adult↗
PubMed2005

Leflunomide in rheumatoid arthritis: recommendations through a process of consensus.

OBJECTIVES: To determine, by consensus, the optimal use of leflunomide in rheumatoid arthritis (RA), using a multidisciplinary panel of experts and performing meta-analyses of available data. METHODS: A multidisciplinary panel of experts in RA was convened. Important questions, pertinent to the use of leflunomide in the treatment of RA, were defined by consensus at an initial meeting. Each question was allocated to subgroups of two or three members, who worked separately to prepare a balanced opinion, based on published literature, data from individual patients taking part in phase II and phase III clinical trials provided by Aventis, and data from a USA-based medical claims database (AETNA). The full group then reconvened to agree on an overall consensus statement. Recommendations concerning efficacy and tolerability versus comparator drugs and placebo were derived from two new meta-analyses. RESULTS: Leflunomide was at least as effective as sulphasalazine and methotrexate, and equally well tolerated on meta-analysis of trial data. Overall withdrawal rates for all adverse events were similar for all three drugs. Avoidance of the loading dose reduces 'nuisance' side-effects (e.g. nausea), but probably delays the onset of action. Adverse events could usually be managed by dose reduction and/or symptomatic therapy. CONCLUSIONS: On the basis of efficacy, safety and cost, leflunomide should be considered in patients with RA who have failed first-line DMARD drug therapy. In refractory cases, leflunomide may be used in combination with, for example, methotrexate before biological agents. Therapy should be initiated by a specialist, but repeat prescribing in general practice on a shared care basis is acceptable using agreed protocols. Clear mechanisms are required to monitor toxicity, with good communication between the patient and rheumatologist to manage nuisance side-effects and avoid unnecessary discontinuation of leflunomide.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Treatment for Lambert-Eaton myasthenic syndrome.

BACKGROUND: Lambert-Eaton myasthenic syndrome is an autoimmune presynaptic disorder of neuromuscular transmission. Treatments have attempted to overcome the harmful autoimmune process, or to improve residual neuromuscular transmission, in order to reverse the principal neurological symptom of muscle weakness. OBJECTIVES: The objective was to examine the efficacy of all forms of treatment in Lambert-Eaton myasthenic syndrome. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group specialised trials register (September 2002), MEDLINE (January 1966 to November 2002) and EMBASE (January 1980 to November 2002). We checked the bibliographies in reports of the randomised trials and contacted authors to identify additional published or unpublished data. SELECTION CRITERIA: Types of studies: all randomised or quasi-randomised trials. TYPES OF PARTICIPANTS: all adults and children with a diagnosis of Lambert-Eaton myasthenic syndrome, with or without small-cell lung cancer. Types of interventions: any form of medical (pharmacological or physical) treatment. Types of outcome measures: Primary: change in the muscle strength scale score (Quantitative Myasthenia Gravis score), or limb muscle strength measured by myometry. Secondary: improvement in the mean amplitude of the resting compound muscle action potentials. The mean amplitude used was the mean of all muscles tested. DATA COLLECTION AND ANALYSIS: We identified three randomised controlled trials. Individual patient data were only available for one trial. MAIN RESULTS: The three eligible trials included two controlled trials of the effects of 3,4-diaminopyridine compared with placebo in a total of 38 patients with Lambert-Eaton myasthenic syndrome, one of which was of crossover design. A third crossover trial compared intravenous immunoglobulin treatment to placebo in nine patients with Lambert-Eaton myasthenic syndrome. A meta-analysis of the primary endpoint results of these trials was not possible because of differences in comparisons and endpoints and, in two trials, lack of individual patient data. EFFECTS OF 3,4-DIAMINOPYRIDINE: Two trials of 3,4-diaminopyridine reported a significant improvement in the primary endpoint of muscle strength score, or myometric limb measurement following treatment. Both trials also reported a significant improvement in the secondary endpoint of resting compound muscle action potential amplitude following 3,4-diaminopyridine, compared with placebo. A meta-analysis of the primary endpoint results was not possible because of marked differences in these two trials regarding primary outcome measures. However, a meta-analysis of the secondary endpoint (improvement in the amplitude of the mean resting compound muscle action potential) was possible. It was necessary to assume a known correlation (similarity) of the paired responses for each individual in the two treatment periods in order to properly allow for the crossover design of one of the two trials (the correlation coefficient was assumed to be 0.5 in calculations). Using this approach, meta-analysis revealed a significant overall benefit in compound muscle action potential amplitude after 3,4-diaminopyridine treatment. The overall weighted mean difference was 1.80 mV (95% confidence interval 0.82 to 2.78), favouring treatment. These results were not sensitive to the assumption made because the overall benefit estimated was still significant when the correlation was assumed to be less than 0.1. EFFECTS OF INTRAVENOUS IMMUNOGLOBULIN: A crossover trial reported a significant improvement in the primary outcome measure of myometric limb strength when patients received intravenous immunoglobulin compared to placebo infusions. This trial also demonstrated an improvement in the secondary outcome measure of change in the mean resting compound muscle action potential amplitude following intravenous immunoglobulin, but this improvement did not reach significance. Clinical improvement lasted for up to eight weeks. REVIEWER'S CONCLUSIONS: Limited evidence from randomised controlled trials showed that either 3,4-diaminopyridine or intravenous immunoglobulin improved muscle strength scores and compound muscle action potential amplitudes in patients with Lambert-Eaton myasthenic syndrome. There are insufficient data at present to quantify this treatment effect. Other possible treatments, such as plasma exchange, steroids and immunosuppressive agents have not been tested in randomised controlled trials.

4-Aminopyridine↗
PubMed2002

Mutational spectrum of the CHAC gene in patients with chorea-acanthocytosis.

Chorea-acanthocytosis (ChAc) is an autosomal recessive neurological disorder whose characteristic features include hyperkinetic movements and abnormal red blood cell morphology. Mutations in the CHAC gene on 9q21 were recently found to cause chorea-acanthocytosis. CHAC encodes a large, novel protein with a yeast homologue implicated in protein sorting. In this study, all 73 exons plus flanking intronic sequence in CHAC were screened for mutations by denaturing high-performance liquid chromatography in 43 probands with ChAc. We identified 57 different mutations, 54 of which have not previously been reported, in 39 probands. The novel mutations comprise 15 nonsense, 22 insertion/deletion, 15 splice-site and two missense mutations and are distributed throughout the CHAC gene. Three mutations were found in multiple families within this or our previous study. The preponderance of mutations that are predicted to cause absence of gene product is consistent with the recessive inheritance of this disease. The high proportion of splice-site mutations found is probably a reflection of the large number of exons that comprise the CHAC gene. The CHAC protein product, chorein, appears to have a certain tolerance to amino-acid substitutions since only two out of nine substitutions described here appear to be pathogenic.

Chorea↗
PubMed2002

Prevention of vascular damage in scleroderma with angiotensin-converting enzyme (ACE) inhibition.

Great strides have been made in identifying and managing the organ-based complications of systemic sclerosis (SSc). There is no room for the nihilism towards treating this disease that used to be so prevalent. However, there is still relatively little hard evidence on which to base treatment decisions. Previous trials have been constrained by the low disease prevalence and the difficulty in recruiting sufficient patients especially with disease of recent onset. The results of past trials have often been confounded by the failure to recognize the marked heterogeneity of SSc and the inclusion of patient subsets with widely varying disease expression, course and outcome. It is recognized that progress will only be made in this area with coordinated multicentre studies. As a result, national and international networks of clinicians with expertise in the management of SSc have been formed. In the UK, the Systemic Sclerosis Study Group has established a national scleroderma register and, together with the Scleroderma Special Interest Group of the British Society for Rheumatology (BSR), a multicentre base for therapeutic studies. As a result of developments in our understanding of the pathogenesis of scleroderma and our ability to subset patients more effectively, a number of rather more rational approaches to treating the disease and its complications are being tested. In parallel with this, considerable progress is being made in developing universally agreed measures of disease activity and severity and in identifying surrogate laboratory markers of disease activity that are relevant to therapeutic studies. These multicentre trials need substantial funding and often do not attract support from the pharmaceutical industry. It was because of the difficulty in financing long-term, multicentre studies in uncommon conditions that the ARC/BSR Clinical Trials Programme was established. The QUINS trial, which is funded by this Programme, is described here as an example of one of several therapeutic protocols being developed by the UK Systemic Sclerosis Study Group that are currently being tested in multicentre trials. Contact details are provided in the appendix for clinicians who are interested in registering patients on the UK Scleroderma Register or participating in this or in the other therapeutic studies.

Adolescent↗
PubMed2001

Long term outcome in Lambert-Eaton myasthenic syndrome without lung cancer.

OBJECTIVES: To determine the prognosis in patients with Lambert-Eaton myasthenic syndrome (LEMS) without small cell lung cancer (SCLC), and to analyse longitudinal clinical, electrophysiological, and immunological data on each patient to establish prognostic factors for long term outcome. METHODS: The retrospective and part prospective study of 47 patients with LEMS was undertaken from data recorded during visits to a specialist neuromuscular clinic. Serial measurements of muscle strength score in shoulder abduction, elbow extension and hip flexion, compound muscle action potential (CMAP) amplitude, and postcontraction increment in abductor digiti minimi (ADM), and anti-P/Q-type voltage gated calcium channel (VGCC) antibody titre were made at each visit. RESULTS: Muscle strength scores were improved in 88% of patients after a median duration of immunosuppressive treatment of 6 years (range 1.3 to 17 years); anti-VGCC antibody titres fell in 52% after treatment; and mean resting CMAP amplitude improved from 2.7 mV initially to 8.8 mV after 2 years of treatment p<0.001). Initial pretreatment anti-VGCC antibody titre did not correlate significantly with either CMAP amplitude, CMAP increment, or clinical score: from serial measurements made during follow up, significant correlation between antibody titre and CMAP amplitude was seen in only two patients. Sustained clinical remission was achieved by 20 (43%) of whom only four remained in remission without the need for immunosuppression. Using a Cox proportional hazards model, the only independent predictor of sustained clinical remission was initial pretreatment clinical score (p=0.03). Lymphoma presented in three patients during the study. CONCLUSIONS: The prognosis in patients with LEMS without SCLC is favourable, although patients often need significant doses of immunosuppressive treatment to remain clinically stable. Only initial clinical muscle strength measurements and not anti-VGCC antibody titres or electrophysiological recordings are predictive of long term outcome.

Adolescent↗
PubMed2001

Association between insulin-like growth factor status and physical activity levels in rheumatoid arthritis.

OBJECTIVE: To determine if the altered insulin-like growth factor (IGF) status in rheumatoid arthritis (RA) is due to inflammation, altered body composition, or lack of exercise. METHODS: Subjects included 73 patients with RA, 54 patients with other rheumatic diseases, both inflammatory and noninflammatory, and 28 healthy, physically active controls. Serum levels of IGF-I, IGF-II, and IGF binding protein-3 (IGFBP-3) were measured by radioimmunoassay. Body composition was estimated by bioelectrical impedance analysis, and habitual exercise level approximated by questionnaire. Statistical analysis was performed by 2 and 3 way ANOVA and moderated hierarchical regression. RESULTS: Serum IGF-I (p < 0.001), IGFBP-3 (p < 0.001), and the BP-3:total IGF molar ratio (p < 0.001) were depressed in both patient groups relative to controls. In contrast, IGF-II levels were depressed only in patients with RA (p < 0.01). Differences in the IGF proteins between patients and controls could not be attributed to inflammation. Habitual exercise level, but not body composition, was shown to be a significant predictor for IGF-I, IGFBP-3, and BP-3:total IGF molar ratio (p < 0.001). CONCLUSION: Our results indicate that the reduction in circulating IGF proteins observed in our patients is more related to their sedentary lifestyle than to the inflammatory process. This conclusion is in agreement with reports that show that highly active individuals typically exhibit higher levels of systemic IGF proteins than age matched sedentary controls.

Arthritis, Rheumatoid↗