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Biomedical subjects

W W Buchanan

Publications and source records attributed to W W Buchanan.

At least 55 records · Page 3Linked to original sources
PubMed1992

HLA-D region genes and rheumatoid arthritis (RA): importance of DR and DQ genes in conferring susceptibility to RA.

The distribution of HLA-D region antigens was studied in three groups (I, IIa, and IIb) of patients with rheumatoid arthritis (RA): group I comprised 43 patients with mild, non-progressive RA, controlled by non-steroidal anti-inflammatory drugs without progression or erosions; group II comprised 94 patients with severe disease, who had earlier been treated with non-steroidal anti-inflammatory drugs and all had incomplete response requiring treatment with gold (sodium aurothiomalate). Of these, 46 patients (group IIa) responded to gold and the disease was well controlled, and the remaining 48 patients (group IIb) did not respond to gold and developed gold induced toxic reactions, including thrombocytopenia or proteinuria, or both. HLA-D region antigens were defined by serological and molecular (Southern blot analysis and oligonucleotide typing) techniques. The results show that DR4 was significantly increased in all three groups of patients. The prevalence of DR1, or DR1 in DR4 negative patients, and DR3 and DR4 associated DQw7 specificities, however, showed differences in these three groups of patients. The prevalence of DR1 and of DR1 in DR4 negative patients was increased only in patients with mild (group I) RA, but not in patients with severe (groups IIa and IIb) disease. On the other hand, the prevalence of DR4 associated DQw7 was significantly increased in patients with severe disease, but not in patients with mild RA. In addition, DR3 was significantly increased only in patients with severe disease who developed gold induced toxic reactions (group IIb). These data suggest that the HLA-D region genes which cause susceptibility to mild RA may be different from those causing susceptibility to severe RA. The results suggest that both DR and DQ (A, B) genes may be important in conferring susceptibility to RA: DR in mild disease and DQ in severe RA.

Antibodies, Antinuclear↗
PubMed1992

Nocturnal pain correlates with effusions in diseased hips.

Thirty-five of 50 patients with different hip joint disease had sonographic evidence of joint effusion. Arthrocentesis confirmed effusions in 30 of these 35 patients. Thirty-two of the 35 patients had nocturnal pain. Both nocturnal pain and sonographic evidence of effusion decreased after aspiration (15 patients) and aspiration and injection of corticosteroids (15 patients). In a further group of 61 patients who subsequently had Charnley arthroplasties, 35 had positive sonograms before operation. Of these, 25 had effusions confirmed at operation, the remaining 10 having synovitis and capsule thickening. Again a correlation was found with nocturnal pain. The sensitivity of sonography in detecting hip joint effusion was 92% with a specificity of 70%. Nocturnal pain had a lower sensitivity, 85%, but higher specificity, 94%.

Adrenal Cortex Hormones↗
PubMed1992

Double blind randomized controlled trial of sodium meclofenamate (Meclomen) and diclofenac sodium (Voltaren): post validation reapplication of the WOMAC Osteoarthritis Index.

Following several years of development and validation, we applied the WOMAC Osteoarthritis Index as the principal outcome measure in a double blind randomized parallel trial of Meclomen (100 mg po tid) and Voltaren (25 mg po tid). Statistically significant improvements in clinical status were noted in both treatment groups. At the doses studied, between drug differences favoring Meclomen were observed in pain and stiffness, no difference being noted in physical function. No significant between drug difference was noted in tolerability at these same doses. Our study also demonstrated that the relative efficiency of WOMAC was similar to that of the Lequesne and Doyle indices. Finally, we defined the standard deviation necessary to calculate sample size for future studies using the WOMAC index, both for studies based on static scores and those based on change scores.

Adult↗
PubMed1991

HLA-D region antigens in patients with rheumatoid arthritis.

We studied the distribution of HLA-D region antigens in 2 groups of rheumatoid arthritis (RA) patients: those with mild, nonprogressive disease, and those with severe disease. The results demonstrate that DR4 was significantly increased in both RA patient populations. The frequencies of DR1 and DR4-associated DQw7 alleles, however, were different in these 2 groups of patients. DR1 was significantly increased only in patients with mild RA, and DR4-associated DQw7 was significantly increased only in patients with severe disease. The results of the present study, together with previous data from our laboratory and from other investigators on the incidence of HLA-D region antigens in RA, suggest that both DR and DQ (A and B) genes may be important in conferring susceptibility to RA; DR in the mild forms of the disease, and DQ in severe RA.

Alleles↗
PubMed1991

Action of gold sodium thiomalate on experimental thrombosis in vivo.

In order to study the effect of gold compounds on the action of thrombin in vivo, experiments were performed to measure platelet survival and the weight of thrombus formation in experimental models of intra-aortic thrombosis by two indwelling aortic catheter methods. We have called these the long and short catheter methods. Platelet survival was reduced in all gold-treated and control animals which had indwelling aortic catheters. In the long catheter model, New Zealand White male rabbits were treated with one of the following: gold sodium thiomalate, sterile water, gold thioglucose, gold sodium thiosulfate, disodium thiomalate. Gold sodium thiomalate-treated rabbits had a reduced weight of experimentally induced intra-aortic thrombi compared with animals treated with sterile water or equimolar concentrations of gold thioglucose, gold sodium thiosulfate, or disodium thiomalate. This reduction in thrombus weight in the animals treated with gold sodium thiomalate was not reflected by changes in platelet survival or fibrinolysis. The serum gold levels achieved in these in vivo experiments was in the range of 5.0 X 10(-5) to 1.0 X 10(-4) M. These values are comparable to levels which can be achieved in human subjects immediately after a gold injection. In the short catheter model, New Zealand White male rabbits were treated with either gold sodium thiomalate, gold thioglucose, disodium thiomalate, or auranofin. Controls were given either water or 0.05% chlorocresol. Water-treated and gold sodium thiomalate-treated animals were also given 51Cr-labeled platelets and 125I-fibrinogen before insertion of the catheter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Is diet important in rheumatoid arthritis?

There is evidence from several well documented case reports that occasional patients with rheumatoid arthritis (RA) may develop aggravation of their arthritis as a result of allergy to some ingredient in the diet. A variety of foodstuffs have been implicated including milk and milk products, corn and cereals. Total fasting results in improvement in rheumatoid arthritis, but appears to be mediated by diminution in production of chemical mediators of inflammation, rather than by elimination of a dietary allergen. There is conflicting evidence from studies using various intestinal probes that patients with rheumatoid arthritis may have a 'leaky' intestinal mucosa allowing food allergens to be more easily absorbed. Clinical therapeutic trials of exclusion diets have employed the standard strategy of the double-blind randomized method. However, this presupposes that patients entered into such a study are capable of improvement with dietary manipulation. Since this is often not the case, a more appropriate method would be to employ the 'intensive research design' also known as 'single case experiment' and 'N of 1' study. 'Masked food intolerance' is an attractive hypothesis, but extremely difficult to prove. It is doubtful whether fish oils and/or evening primrose oil will be of significant long term benefit for patients with RA. However, they do provide for the possibility that a fatty acid-like substance may be found which may be incorporated into cell membranes, thereby preventing production of mediators of inflammation, such as prostaglandin E2 and leukotriene B4.

Animals↗
PubMed1991

Methods of assessment used in ankylosing spondylitis clinical trials: a review.

Twenty non-steroidal anti-inflammatory drug (NSAID) trials in ankylosing spondylitis (AS) were reviewed to assess the frequency with which statistically significant differences had been detected between active drug and either a placebo or an NSAID-free washout period. Differences in pain severity were almost invariability detected, irrespective of the scale employed. In contrast, significant differences in axial movement were rarely detected in placebo controlled studies, and only about half of the variables detected significant improvement with respect to a washout period. From our data it is difficult to differentiate whether the lack of difference with active therapy was due to inadequate sample size, non-responsive patients, or insensitive outcome measures. However, it is not surprising that between-drug differences are rarely detected in AS clinical trials of NSAIDs given our current inability to differentiate consistently an active treatment from a placebo and an active treatment phase from a washout period.

Analgesics↗
PubMed1991

Circadian rhythm in pain, stiffness, and manual dexterity in rheumatoid arthritis: relation between discomfort and disability.

Fourteen patients with rheumatoid arthritis (RA) self rated their pain and stiffness on separate 10 cm visual analogue scales and performed bead intubation coordinometry (BIC) on six occasions each day for seven consecutive days. In addition, 14 healthy controls matched for age and sex also performed BIC measurements according to the same schedule. Data were analysed using least squares and cosine vector techniques. Significant circadian rhythms in patients with RA were detected in pain, stiffness, and BIC, and in controls in BIC. Pain was least in patients with RA at 1700 and stiffness at 1724. Peak BIC performance occurred almost simultaneously in RA (1544) and control (1528) subjects and for subjects with RA occurred within the 95% confidence interval of least pain and stiffness. These data suggest that the inferior performance of subjects with RA may be an accentuation of the normal physiological variation seen in healthy controls, but may be modulated by the patient's level of pain or stiffness, or both.

Adult↗
PubMed1991

Clinical evaluation of a sustained release compared to a standard formulation of tiaprofenic acid (Surgam) in rheumatoid arthritis: a Canadian multicenter study.

A double blind, randomized, parallel group clinical therapeutic trial, comparing a sustained release formulation with a standard preparation of tiaprofenic acid (Surgam), was performed in 119 patients with rheumatoid arthritis. The sustained release preparation was prescribed as two 300 mg capsules taken once a day, and the standard formulation as one tablet of 300 mg taken twice a day. From baseline up to the 3rd and 6th week of treatment, a statistically significant difference (p less than 0.001) was observed in both treatment groups for all the variables, indicating objective or subjective changes in the clinical signs and symptoms of the patients. For most of these variables, no significant differences were observed between the sustained release and the standard formulations. Also, no significant differences were observed between the 2 formulations in the incidence of side effects and abnormal laboratory findings.

Adult↗
PubMed1991

Ankylosing spondylitis antirheumatic drug trials. I. Effects of standardization procedures on observer dependent outcome measures.

We designed a study to assess the effects of standardization procedures on reducing interobserver variability for outcome measures given in the current Food Drug Administration and European League Against Rheumatism guidelines and others selected from the rheumatology literature. Over 2 days, 6 rheumatologists independently examined 7 patients with ankylosing spondylitis (AS) in predetermined order before and after standardizing their examination techniques. An important and beneficial effect of the standardization procedure was observed on the majority of outcome variables. Such reductions in observer variability have the potential to diminish sample size requirements for AS antirheumatic drug studies.

Adult↗
PubMed1991

Ankylosing spondylitis antirheumatic drug trials. II. Tables for calculating sample size for clinical trials.

The calculation of sample size requires knowledge of the standard deviation (SD) of index variables. Unfortunately, there are no published lists of standard deviations and it is exceedingly difficult to locate variance estimates based on relevant populations. We used standardized procedures to determine in 60 patients with ankylosing spondylitis (AS) the SD of key outcome measures recommended in current Food Drug Administration and European League Against Rheumatism guidelines for AS clinical trials. We anticipate that these tables will be useful to clinical researchers in selecting outcome measures as well as for calculating sample size requirements for future clinical studies in AS.

Analysis of Variance↗