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Biomedical subjects

D M Mitchell

Publications and source records attributed to D M Mitchell.

At least 109 records · Page 6Linked to original sources
PubMed1987

Rheumatoid arthritis of the cervical spine: early and progressive radiographic features.

One hundred thirty-three cervical spine radiographs of 50 patients with rheumatoid arthritis were examined. The patients were a representative random sample chosen from among 675 patients followed up for more than 10 years. The frequency of occurrence for each radiographic finding was correlated with the duration of rheumatoid arthritis. The six radiographic findings that occurred in 30% or more of patients with a disease duration of less than 10 years included odontoid erosions, subaxial subluxation, superficial apophyseal joint erosions, apophyseal joint sclerosis at levels C-4 through C-7, and diskovertebral joint narrowing and osteophytosis at C-4 through C-7. Familiarity with these early findings in the cervical spine may be helpful in both diagnosing and managing rheumatoid arthritis. Subaxial subluxation and superficial apophyseal joint erosions did not progressively increase in frequency with increasing duration of disease, but the other four features did. Other features that were uncommon in early disease became significantly more frequent in later decades.

Adolescent↗
PubMed1987

Disability in rheumatoid arthritis: comparison of prognostic factors across three populations.

We previously identified variables that predict functional disability in rheumatoid arthritis (RA). Because of potential instabilities in the statistical model, we sought to determine whether these predictors were consistent across populations: 2,448 consecutive patients with (RA) were followed prospectively at ARAMIS centers in Phoenix, AZ, Wichita, KS, and Saskatoon, SK. Average followup was 1.7 years in Phoenix, 3.4 years in Wichita, and 12 years in Saskatoon. Twenty-four potentially predictive variables were analyzed by stepwise linear regression. Common predictors were age, sex, and duration of illness, suggesting that these variables are important predictors of disease regardless of the population being studied. In addition, the initial level of disability and radiographic variables are good predictors of disability. Elevated erythrocyte sedimentation rate and latex titers also were associated with future functional disability but do not have a linear relationship and predict less well.

Adolescent↗
PubMed1986

A multicenter study of annual health service utilization and costs in rheumatoid arthritis.

The economic impact of chronic illness has important implications for medical practice and health policy. To determine the yearly costs of illness for those who have rheumatoid arthritis, a detailed, self-administered questionnaire was developed. The questionnaire was completed by 940 patients. Direct costs (recorded as charges) include the average annual expenditures by all patients and third party payers for: hospital care ($913), physician costs ($206), other health professional visits ($71), medications ($436), laboratory tests ($217), radiographs ($116), assistive devices ($24), and nontraditional therapies ($22). The total annual medical costs per patient were $2,533. In a multivariate analysis that controlled for age, sex, education, and disease duration, the outpatient costs, inpatient costs, and total costs were all positively related to the Health Assessment Questionnaire Disability Index (P f less than 0.01) and global health (P f less than 0.01), but were not associated with self-reported pain.

Arthritis, Rheumatoid↗
PubMed1986

The development of disability in rheumatoid arthritis.

Six hundred eighty-one consecutive patients with rheumatoid arthritis were followed for an average of 11.9 years to identify initial factors that predicted subsequent disability. Of 39 potentially predictive variables obtained at study onset and studied by stepwise regression methods, age was found to be the most powerful single predictor of disability, followed by radiologic grade, sex, and initial functional class. The worst prognosis for disability was found in patients who were older women and who showed radiologic worsening and developed functional impairment early in the disease course. Both disability and radiologic progression of disease were found to develop most rapidly during the first years after disease onset and to assume a slow, nearly linear rate of increase after 10 years. Approximately 10% of patients did not develop significant disability. This study suggests that it is possible to identify, early in the disease course, those patients who are likely to develop severe disability, and that "disease-modifying" therapy might well be initiated earlier in such patients and used consistently throughout the subsequent treatment.

Aged↗
PubMed1986

Impact of specific therapy upon rheumatoid arthritis.

We performed a prospective, parallel, descriptive study of 737 consecutive new uses for 11 drugs prescribed for patients with definite or classic rheumatoid arthritis. The patients were from 5 geographically dispersed sites. Researchers used validated outcome assessment instruments to measure endpoints of disability, pain, patient global assessment, medication costs, laboratory costs, and number of physician visits. Patients were studied by strict prospective protocol at 6-month intervals for 3 years. Controls included parallel results with other drugs, and before and after values for the individual patient. Beneficial effects were observed with the "disease-modifying" drugs: intramuscular gold, penicillamine, and methotrexate. Of these, gold had the most apparent effect. An average of 9 months of gold therapy resulted in highly significant reductions in disability (P less than 0.005), pain (P less than 0.001), and patient global assessment (P less than 0.005). However, patients receiving gold and methotrexate had nearly twice as many visits to physicians. In addition, drug costs increased strikingly with gold, and laboratory costs tripled. Relatively minor differences among nonsteroidal antiinflammatory agents were difficult to interpret. The outcome assessment techniques used in the study are sensitive measures, which confirm the results of experimental studies and extend observations to new outcomes, including cost and disability.

Anti-Inflammatory Agents↗
PubMed1986

Survival, prognosis, and causes of death in rheumatoid arthritis.

The factors associated with mortality were examined in a prospective longitudinal study, over an average of 12 years, with 94% followup of patients diagnosed as having rheumatoid arthritis. Of 805 patients, 233 died during the period of the study. Survivorship of rheumatoid arthritis patients was approximately 50% less than that of population controls. Survivorship was decreased by the traditional demographic variables of greater age and male sex; however, a significant independent effect of variables reflecting disease severity (American Rheumatism Association functional class, rheumatoid factor titer, number of involved joints) was identified by multivariate analysis. Seventy-nine excess deaths (i.e., those that would not have been expected in a control population) were due in part to disease-related causes, to infections, and to gastrointestinal complications of therapy. Treatment with gold or prednisone did not seem to affect survivorship or cause of death, except for the clustering of deaths of patients with vasculitis within the prednisone group. Our findings indicate that rheumatoid arthritis, a chronic disabling disease, is also associated with a major decrease in survivorship.

Age Factors↗
PubMed1986

Incidence of pulmonary nodules detected by computed tomography in patients with bronchial carcinoma.

Computed tomography (CT) is more sensitive in detecting pulmonary nodules than conventional chest radiography. The incidence of pulmonary nodules on thoracic CT scans, not visible on chest radiographs, in patients with small-cell carcinoma of the bronchus (SCCB) was 27%, and in patients with non-small-cell carcinoma (non-SCCB) the incidence was 28%. Some of these nodules may be malignant. This has implications for the surgical staging of patients with lung cancer in the United Kingdom, where there is a lower incidence of benign granulomatous nodules than in the USA.

Carcinoma, Bronchogenic↗
PubMed1986

Value of serial peak expiratory flow measurements in assessing treatment response in chronic airflow limitation.

A double blind, randomised, placebo controlled, crossover trial of prednisolone (40 mg/day for 14 days) was carried out in 33 patients with chronic airflow limitation (mean age 62 years, mean FEV1 1.01 litres, mean FEV1/FVC ratio 44%), to assess the value of serial peak expiratory flow (PEF) measurements, taken five times daily in evaluating treatment response by comparison with other objective measurements and with measurements of symptoms. The mean serial PEF after a one week run in period was 189 1 min-1, during the second week of placebo 193 1 min-1, and during the second week on prednisolone 231 1 min-1. The difference in mean PEF values between placebo and prednisolone was significant (p less than 0.01). With regard to the response to steroids of the individual patients, 13 of the 33 had a detectable trend of improvement on visual inspection of serial PEF measurements during prednisolone treatment but only one during placebo administration. Of all the objective measurements made after the run in and after each treatment phase (12 minute walking distance, FEV1, forced vital capacity (FVC), serial PEF), the serial PEF chart provided the best discrimination between placebo and prednisolone treatment. There was no statistically significant association between steroid induced improvement in serial PEF measurements and in breathlessness, partly because of placebo improvements in symptoms in those who had no improvement in serial PEF values. This study indicates the importance of making objective measurements to identify a genuine steroid response rather than relying on symptomatic improvement alone. The best simple measurement to make is serial PEF during steroid trials. This is more sensitive in detecting a steroid response than are the 12 minute walking distance, FEV1, or FVC, and is also less likely than these measurements to show spurious placebo responses.

Aged↗
PubMed1986

A multicenter study of hospitalization in rheumatoid arthritis: effect of health care system, severity, and regional difference.

During 1981, centers in Phoenix, Saskatoon, Stanford and Wichita monitored hospitalizations for 816 patients with rheumatoid arthritis. Admission rates varied 2-fold, and admissions for evaluation and treatment 10-fold across centers. Admissions were related primarily to disease severity, but in US centers, were reduced by a factor of 3 by prepaid health care. Length of stay was shortest in California (7.3 days), and longest in Saskatoon (16.3) where designated arthritis beds and government prepaid health care existed. Average charges for surgery were as high as $10,000 in Phoenix and as low as $4550 in Wichita. Charges and length of stay were unrelated to disease severity, but were responsive to health care delivery system, availability of facilities, and geographic and center variation.

Arizona↗
PubMed1985

Cancer in rheumatoid arthritis: a prospective long-term study of mortality.

Eight hundred and five consecutive patients with definite or classic rheumatoid arthritis, representative of a general population, were followed prospectively over an average of 12 years with 94 percent follow-up, during which time 233 patients died. Mortality rates were increased in rheumatoid arthritis by approximately 50 percent compared with population controls. "Excess deaths" (78) were due, in part, to disease-related causes, infections, and gastrointestinal problems secondary to therapy. Thirty-one deaths (14.1 percent) were due to malignancy, compared with 22.8 percent in non-age-adjusted population controls. Frequency of malignancy type (colon seven, lung four, breast three, prostate three, leukemia three, ovary three, stomach two, and lymphoma zero) did not differ significantly from the general population. Age-adjusted figures showed lower malignancy rates for patients with rheumatoid arthritis except after age 80. Two treatments were suitable for analysis. Gold-treated patients trended toward lower malignancy rates (11 versus 17 percent) than did those not treated with gold, and prednisone-treated patients had less malignancy (11 versus 20 percent) than did those not treated with prednisone. These data indicate that there is not an important increase in deaths due to malignancy in rheumatoid arthritis, and that at least two treatments, gold and prednisone, are not associated with higher risk of malignancy.

Adolescent↗
PubMed1985

Laser therapy in 100 tracheobronchial tumours.

One hundred patients with tracheobronchial tumours were treated with the neodymium YAG (yttrium-aluminium-garnet) or argon laser for symptoms of airways obstruction caused by tumour (59 cases), complete collapse of a lung (17 cases), or recurrent haemoptysis (24 cases). Seventy four of them had relapsed or failed to respond to radiotherapy or chemotherapy and all were inoperable. Objective improvement in results of lung function tests or haemoptysis diary charts was seen in 37 patients with airways obstruction (63%), five (29%) with collapsed lung, and 14 (58%) with haemoptysis. Overall, 68 patients had symptomatic benefit and there was objective improvement in 56. Two deaths occurred in 288 treatment sessions both occurring as a result of asphyxia from minor haemorrhage in patients with advanced cylindromas and critical narrowing of the trachea or single remaining bronchus. In suitable patients with intraluminal tumour laser phototherapy is a valuable addition to conventional treatment.

Adult↗
PubMed1984

Effects of prednisolone in chronic airflow limitation.

A double-blind, randomised, placebo-controlled, crossover trial of prednisolone (40 mg daily for 14 days) was carried out in 43 patients with chronic airflow limitation (mean age 60 years, mean FEV1 1.02 litres, FEV1/FVC ratio 43.7%). Several subjective and objective variables for response were measured. Significant improvements occurred with prednisolone in most variables measured, but improvements also occurred with placebo in some variables. The improvements with prednisolone in general wellbeing, 12 min walk distance, peak expiratory flow, FEV1, and relaxed vital capacity were significantly greater than those with placebo. Clinical assessment and assessment of atopic status did not reveal any feature of major predictive value for steroid responsiveness. A proportion of patients with chronic airflow limitation do improve on oral corticosteroids and the continued use of such trials in clinical practice is justified, though a placebo period should be included, and several variables for response should be measured.

Adult↗
PubMed1984

Psychological changes and improvement in chronic airflow limitation after corticosteroid treatment.

Corticosteroids may produce mood changes. This could account for improvement in patients with chronic airflow limitation following trials of oral corticosteroid treatment as mood elevation might improve performance in objective measurements. This proposition was tested in 21 patients with chronic airflow limitation, who underwent detailed psychological assessment during a randomised controlled double blind crossover trial of the effect of prednisolone 40 mg daily compared with that of a placebo. Self rating visual analogue scales for various qualities of mood were completed before the study and after each phase in addition to depression and psychological symptom questionnaires. After treatment with the placebo, patients showed increases in cheerfulness (p less than 0.01) and sociability (p less than 0.01) and a decrease in depression (p less than 0.01). After treatment with prednisolone there were increases in cheerfulness (p less than 0.01), optimism (p less than 0.01), activity (p less than 0.05), and sociability (p less than 0.02) and there was a decrease in depression (p less than 0.01). When placebo and prednisolone values were compared, however, there were no significant differences. Some patients showed improvements (greater than 20%) in peak expiratory flow, FEV1 or forced vital capacity (FVC) after prednisolone, but nearly all had improvements in at least one psychological test. There were no detectable associations between changes in objective measurements and changes in psychological test ratings. This study suggests that in patients with chronic obstructive lung disease significant psychological changes are no more likely to follow treatment with a corticosteroid than treatment with a placebo and that physiological improvement after corticosteroid treatment is not tied to psychological changes.

Aged↗
PubMed1984

Felty's syndrome in a child.

The occurrence of the triad of leukopenia, splenomegaly and rheumatoid arthritis (RA) (Felty's syndrome) during childhood has not been reported previously. We describe an adolescent with onset during childhood of seropositive, nodular, erosive, polyarticular RA in whom both leukopenia and splenomegaly were accompanying features. Neither nonsteroidal antiinflammatory agents nor plasmapheresis were therapeutically beneficial, but low dose oral prednisone therapy resulted in both clinical and hematological improvement.

Anti-Inflammatory Agents↗
PubMed1983

Production of human monoclonal antibody to X31 influenza virus nucleoprotein.

In vitro stimulation of human peripheral blood mononuclear cells with X31 influenza virus antigen has been used to enrich for specific anti-X31 antibody-producing cells. Following Epstein-Barr virus transformation of these stimulated cells, a cell line which produces human antibody to X31 virus was derived and subsequently cloned. The cloned cells secrete and IgGl kappa antibody which is directed against the nucleoprotein of A type influenza virus. Culture supernatants contain 10 to 20 micrograms/ml of specific antibody which is now used as a standard for the ELISA assay used in our laboratory to detect antibodies to influenza virus.

Antibodies, Monoclonal↗