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Biomedical subjects

G Nuki

Publications and source records attributed to G Nuki.

At least 37 records · Page 2Linked to original sources
PubMed1998

Treatment of rheumatoid arthritis with recombinant human interleukin-1 receptor antagonist.

OBJECTIVE: To evaluate the efficacy and safety of interleukin-1 receptor antagonist (IL-1Ra) in patients with rheumatoid arthritis (RA). METHODS: Patients with active and severe RA (disease duration <8 years) were recruited into a 24-week, double-blind, randomized, placebo-controlled, multicenter study. Doses of nonsteroidal antiinflammatory drugs and/or oral corticosteroids (< or =10 mg prednisolone daily) remained constant throughout the study. Any disease-modifying antirheumatic drugs that were being administered were discontinued at least 6 weeks prior to enrollment. Patients were randomized to 1 of 4 treatment groups: placebo or a single, self-administered subcutaneous injection of IL-1Ra at a daily dose of 30 mg, 75 mg, or 150 mg. RESULTS: A total of 472 patients were recruited. At enrollment, the mean age, sex ratio, disease duration, and percentage of patients with rheumatoid factor and erosions were similar in the 4 treatment groups. The clinical parameters of disease activity were similar in each treatment group and were consistent with active and severe RA. At 24 weeks, of the patients who received 150 mg/day IL-1Ra, 43% met the American College of Rheumatology criteria for response (the primary efficacy measure), 44% met the Paulus criteria, and statistically significant improvements were seen in the number of swollen joints, number of tender joints, investigator's assessment of disease activity, patient's assessment of disease activity, pain score on a visual analog scale, duration of morning stiffness, Health Assessment Questionnaire score, C-reactive protein level, and erythrocyte sedimentation rate. In addition, the rate of radiologic progression in the patients receiving IL-1Ra was significantly less than in the placebo group at 24 weeks, as evidenced by the Larsen score and the erosive joint count. IL-1Ra was well tolerated and no serious adverse events were observed. An injection-site reaction was the most frequently observed adverse event, and this resulted in a 5% rate of withdrawal from the study among those receiving IL-1Ra at 150 mg/day. CONCLUSION: This study confirmed both the efficacy and the safety of IL-1Ra in a large cohort of patients with active and severe RA. IL-1Ra is the first biologic agent to demonstrate a beneficial effect on the rate of joint erosion.

Adolescent↗
PubMed1998

The relevance of large-vessel vascular disease and restricted ankle movement to the aetiology of leg ulceration in rheumatoid arthritis.

Leg ulceration in rheumatoid arthritis (RA) without systemic vasculitis is a difficult clinical problem and a common cause of morbidity. We have assessed venous function, arterial pressures and range of ankle movement in 23 RA patients with a leg ulcer and compared the results with those in the non-ulcerated contralateral limb and in 25 RA patients matched for age and duration of arthritis. We found evidence of venous insufficiency in RA ulcer patients compared to disease controls. Ankle movement was more restricted in the ulcerated limb compared to the non-ulcerated contralateral leg. There was no difference in large-vessel arterial function between groups. These findings have implications for therapy and rates of healing.

Aged↗
PubMed1997

Hyperpolarisation of cultured human chondrocytes following cyclical pressure-induced strain: evidence of a role for alpha 5 beta 1 integrin as a chondrocyte mechanoreceptor.

Mechanical stimuli influence chondrocyte metabolism, inducing changes in intracellular cyclic adenosine monophosphate and proteoglycan production. We have previously demonstrated that primary monolayer cultures of human chondrocytes have an electrophysiological response after intermittent pressure-induced strain characterised by a membrane hyperpolarisation of approximately 40%. The mechanisms responsible for these changes are not fully understood but potentially involve signalling molecules such as integrins that link extracellular matrix with cytoplasmic components. The results reported in this paper demonstrate that the transduction pathways involved in the hyperpolarisation response of human articular chondrocytes in vitro after cyclical pressure-induced strain involve alpha 5 beta 1 integrin. We have demonstrated, using pharmacological inhibitors of a variety of intracellular signalling pathways, that the actin cytoskeleton, the phospholipase C calmodulin pathway, and both tyrosine protein kinase and protein kinase C activities are important in the transduction of the electrophysiological response. These results suggest that alpha 5 beta 1 is an important chondrocyte mechanoreceptor and a potential regulator of chondrocyte function.

Actins↗
PubMed1997

CD44 expression by leucocytes in rheumatoid arthritis and modulation by specific antibody: implications for lymphocyte adhesion to endothelial cells and synoviocytes in vitro.

Anti-CD44 MoAb IM7 induced the loss of CD44 from mouse leucocytes thereby inhibiting leucocyte migration and joint inflammation in murine arthritis. Thus, targeting CD44 with MoAb may have potential for the treatment of patients with inflammatory joint diseases. Expression of CD44 by peripheral blood (PB) and synovial fluid (SF) leucocytes from rheumatoid arthritis (RA) patients was compared and the ability of IM7 to modulate this expression determined. RASF lymphocytes showed increased CD44 expression compared with those in PB indicative of an activated phenotype. As inflammatory SF did not up-regulate CD44 expression on PB lymphocytes, the increased CD44 expression by SF lymphocytes was a result of the selective homing of CD44(high) cells to the synovium rather than an effect of the synovial environment. RASF granulocytes showed reduced CD44 expression compared with those in PB, again indicative of an activated phenotype. However, this reduction could be induced on PB granulocytes following culture with inflammatory SF and was inhibited by anti-TNF-alpha MoAb, implying that soluble factors in inflammatory SF such as TNF-alpha induced granulocyte activation and CD44 loss. IM7 induced the loss of CD44 from lymphocytes (both from PB and SF) and granulocytes in vitro, but was subsequently re-expressed after 24 h culture in the absence of the MoAb. This loss of CD44 was blocked by serine- and metalloprotease inhibitors implying that IM7 induced the proteolytic cleavage of CD44 by a mechanism similar to that reported for the loss of CD44 from PMA-activated granulocytes. Furthermore, IM7-treated CD44(low) lymphocytes showed reduced adherence to both an endothelial cell line and RA synovial fibroblasts in vitro. The unique ability of IM7 to reduce CD44 expression by lymphocytes suggests that it could prevent lymphocyte extravasation and synovial infiltration in RA as previously reported in murine arthritis.

Antibodies, Monoclonal↗
PubMed1997

Ankylosing spondylitis and secretor status: a re-evaluation.

Non-secretion of ABO blood group substances in body fluids is associated with susceptibility to some bacterial infections. Non-secretors were previously found to be over-represented in patients with ankylosing spondylitis (AS) (49%) compared to controls (27%). Re-evaluation of secretor status in a population of 92 AS patients and 103 controls revealed identical proportions of non-secretors (28%). Of 43 patients studied in both surveys, 6/22 typed initially as non-secretors proved to be secretors using both haemagglutination inhibition assay (HAI) and enzyme-linked immunosorbent assay (ELISA) techniques. Loss of secreted blood group antigens in the saliva is the cause of this mis-typing. Careful attention to the method of collection, handling and preservation of saliva specimens is essential for accurate assessment of secretor status. Therefore, there is no link between secretor status and AS.

ABO Blood-Group System↗
PubMed1997

Faecal flora in spondyloarthropathy.

Enterobacteria, in particular Klebsiella spp., have been implicated in the aetiopathogenesis of ankylosing spondylitis. A comprehensive examination of the faecal flora of 82 patients with ankylosing spondylitis, either primary (67), or in association with inflammatory bowel disease (4), reactive arthritis (6) or psoriatic arthritis (5), was performed and compared with that of a control population (36) of healthy individuals. The range of flora identified was similar in both populations and there was no increased isolation rate of Klebsiella or other proposed arthritogenic organism in those with spondyloarthropathy. In those patients in whom Klebsiella was identified, its presence was not related to disease activity, the erythrocyte sedimentation rate or C-reactive protein.

Acute-Phase Reaction↗
PubMed1996

Effects of intermittent pressure-induced strain on the electrophysiology of cultured human chondrocytes: evidence for the presence of stretch-activated membrane ion channels.

1. Cyclical pressurization of cultured chondrocytes results in increases in cyclic AMP and in the rate of proteoglycan synthesis. Intermittent increases in hydrostatic pressure are also associated with hyperpolarization of chondrocyte cell membranes and activation of Ca(2+)-dependent K(+)-ion channels but the physiological basis for this response to mechanical stimulation is unclear. 2. Experiments have been undertaken to better define the types of ion channels involved and to explore the possibility that the hyperpolarization response associated with cyclical pressurization of chondrocytes follows activation of stretch-activated ion channels. 3. The mean membrane potential of chondrocytes in non-confluent monolayer cell culture rose from -15.3 +/- 0.24 mV to -21.1 +/- 0.28 mV (n = 60, P < 0.0001) after intermittent pressurization (0.33 Hz, 16 kPa, 20 min). 4. Strain gauge measurements showed that cyclical pressurization was associated with strain on the base of the culture plate. The amplitude of the hyperpolarization response was proportional to the microstrain to which cells were subjected. 5. Membrane hyperpolarization did not occur when chondrocytes were subjected to cyclical pressurization in rigid glass culture dishes or plastic dishes positioned in the pressurization chamber so as to avoid bending of the base of the culture dish. 6. Indirect evidence that the hyperpolarization response after intermittent pressure-induced strain was associated with stimulation of stretch-activated ion channels was obtained from experiments with gadolinium, amiloride and hexamethylene amiloride, each of which abolished hyperpolarization. 7. Experiments with apamin, charybdotoxin and iberiotoxin showed that the Ca(2+)-activated K+ channels involved in the hyperpolarization response are apamin-sensitive, charybdotoxin- and iberiotoxin-resistant, low-conductance channels. 8. Somatostatin and cadmium chloride, which block L-type calcium channels, abolished strain-induced chondrocyte hyperpolarization. EGTA, which chelates extracellular Ca2+, reduced the response to 48% of control values, and thapsigargin, which raises intracellular Ca2+ by inhibition of Ca(2+)-ATPase in endoplasmic reticulum, caused hyperpolarization independently with further hyperpolarization after pressure-induced strain. These data indicate that chondrocyte hyperpolarization was dependent on intracellular Ca2+ concentrations. 9. Further work is required to determine whether stretch-activated ion channels shown to be associated with chondrocyte hyperpolarization after cyclical pressure-induced strain are also involved in the signal transduction process that leads to increases in proteoglycan synthesis.

Calcium Channels↗
PubMed1996

Reversible ovulatory failure associated with the development of luteinized unruptured follicles in women with inflammatory arthritis taking non-steroidal anti-inflammatory drugs.

The case histories of three young women with ankylosing spondylitis, rheumatoid arthritis and a seronegative inflammatory polyarthritis undergoing investigations for infertility are presented. In each, non-steroidal anti-inflammatory drug (NSAID) therapy was associated with the recurrent development of luteinized unruptured ovarian follicles and normal ovulation following drug withdrawal. It is suggested that NSAID therapy may be an important and frequently overlooked cause of anovulation and infertility.

Adult↗
PubMed1996

Cervical spine surgery in patients with rheumatoid arthritis: an appraisal.

OBJECTIVES: To review the outcome of surgery undertaken to stabilise the neck in patients with rheumatoid arthritis performed over a five year period, to compare the results with those of previous reports, and to identify factors that may predict surgical outcome. METHODS: Outcome was assessed at time of discharge from hospital after surgery by review of patients' notes, and at follow up by patient interview, clinical examination, anonymous questionnaire, and cervical spine radiograph. The Ranawat classification of neurological impairment and Steinbrocker functional classification were used. RESULTS: Thirty nine patients underwent 44 procedures; 28 patients were available for review after a mean period of 29.8 months (range 12-65 months). Fourteen patients had preoperative neurological impairment and were available for follow up; 13 returned the questionnaire. Four (29%) had improved Ranawat class, nine were unchanged, and one had deteriorated. Nine (69%) reported a subjective improvement in neurological symptoms by questionnaire, even though the Ranawat class was unchanged in five. Twenty five of the patients reviewed had pain before operation; 21 returned the questionnaire. Pain relief was reported by direct questioning and questionnaire in 76% and 67% of patients, respectively. Overall, 67% felt that surgery had been successful. Surgery was more successful in producing symptomatic relief in patients with neck or radicular pain than in those with neurological deficit, but did prevent progression of neurological symptoms. CONCLUSIONS: Our results are similar to those from other centres. Overall patient satisfaction with surgery was good. Surgery was more likely to produce symptomatic relief in patients with neck or radicular pain before operation than in those with neurological deficit. The greater subjective improvement in neurological symptoms as judged by questionnaire probably reflects the relative insensitivity of the Ranawat classification in detecting change in neurological status; previous reports of poor outcome for patients with neurological symptoms who undergo surgery may in part be a reflection of the insensitivity of this method of assessment. No clear factors emerged which allowed prediction of those patients at greatest risk of operative mortality. In particular, an increased risk of neurological compromise appeared to confer no additional risk of immediate perioperative death. Our data support the suggestion that early surgery to correct symptomatic atlantoaxial subluxation may prevent progression of instability.

Adult↗
PubMed1994

Leg ulceration in rheumatoid arthritis.

Chronic leg ulcers occur in 1% of the adult population with considerable associated morbidity, and community costs estimated at up to 600 million pounds p.a. in the UK. Leg ulcers appear to be relatively common in patients with RA and are widely believed to be resistant to treatment. Such ulcers are often attributed to vasculitis, but little is known of the occurrence of other potential aetiological factors. This article reviews the epidemiology, natural history and aetiology of chronic leg ulcers in RA as well as the therapeutic options available.

Adult↗
PubMed1994

Nonsteroidal anti-inflammatory drugs in the treatment of osteoarthritis.

Symptoms and disability vary considerably over time and among individuals with similar degrees of radiographic osteoarthritis. The results of recent clinical studies have reaffirmed that many patients prefer nonsteroidal anti-inflammatory drugs (NSAIDs) to analgesics while also demonstrating that many individuals who have been receiving NSAIDs can manage without them. Certain but as yet poorly characterized patients appear to respond more favorably to treatment with NSAIDs. Thus, both chronic unquestioning use of NSAIDs and denial of NSAIDs to individuals with osteoarthritis are extreme and inappropriate approaches to treatment. Concerns about the gastrointestinal toxicity of NSAIDs remain, although strategies to prevent this toxicity provide some reassurance and should be considered for use in individuals who are at particular risk. These strategies include the use of NSAIDs that are selective inhibitors of the prostaglandin endoperoxide synthase II isoenzyme and are potentially less ulcerogenic or the coprescription of prostaglandin analogues or other ulcer-healing drugs. The costs and benefits of such approaches have yet to be established. Cartilage metabolism is adversely affected by certain NSAIDs in vitro, but the relevance of these observations remains unclear. In our view, the judicious use of NSAIDs in the treatment of osteoarthritis is acceptably safe and indicated in individuals in whom pain cannot be managed by simple analgesics and nonpharmacologic approaches.

Analgesics↗
PubMed1994

Interleukin 1 beta, hand and foot bone mineral content and the development of joint erosions in rheumatoid arthritis.

OBJECTIVE: To assess the relationship between plasma levels of the cytokine interleukin-1 beta (IL-1 beta) and the progression of rheumatoid arthritis (RA). METHODS: Two subgroups of patients, one with persistently raised ESR (>/= 50 mm/hour, n = 16, group A) and one with persistently low ESR (</= 28 mm/hour), n = 18, group I) were chosen to represent stable extremes of inflammatory activity from a prospective study of 106 patients with active RA studied over one year in a single centre. The change from baseline in hand, foot and calcaneal bone mineral content measured by single photon absorptiometry and radiographic score of joint damage was measured over 12 months, together with plasma IL-1 beta and erythrocyte sedimentation rate. RESULTS: Significant progression of joint damage occurred in both subgroups over one year (p < 0.0001, paired t test) though progression was significantly less in the subgroup with low ESR (p < 0.05, ANOVA). Hand and foot bone mineral content decreased by almost 10% in the subgroup with raised ESR (p < 0.005, paired t test). Stepwise linear regression analysis revealed significant independent relationships between radiographic progression over one year and plasma IL-1 beta and ESR (multiple R 0.674, F = 11.64, p < 0.0002). No such relationships were observed for changes in bone mineral content parameters. CONCLUSIONS: Plasma IL-1 beta levels correlate weakly with progression of joint damage though not with loss of peripheral bone density in RA. A significant reduction in peripheral bone mineral content occurs over one year in patients with active RA with persistently raised ESR.

Adult↗