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Biomedical subjects

M Ahern

Publications and source records attributed to M Ahern.

At least 55 records · Page 3Linked to original sources
PubMed1988

Methotrexate kinetics in rheumatoid arthritis: is there an interaction with nonsteroidal antiinflammatory drugs?

Pharmacokinetic drug interaction between methotrexate (MTX) and nonsteroidal anti-inflammatory drugs (NSAID) has been implicated in several case reports of MTX related toxicity. We therefore studied the kinetics of low dose (15 mg) oral MTX with and without concomitant NSAID therapy after preliminary determination of the systemic bioavailability of commercial tablets. Fourteen patients with rheumatoid arthritis, age range 44-77 years, participated in paired kinetic studies performed 1-4 weeks apart. The Abbott TDx fluorescence polarization immunoassay was used to measure serum levels and urinary excretion of MTX over 72 h after a single dose. The mean systemic bioavailability was 73% for the 15 mg oral dose. Area under the serum concentration versus time curve for a 50 mg oral dose was 1.1-2.7 times that of the 15 mg oral dose indicating dose dependent absorption. Mean kinetic variables after oral MTX did not differ significantly with and without NSAID therapy despite apparent interactions in individual patients. Renal clearance of MTX correlated with creatinine clearance (r = 0.8, p less than 0.01).

Adult↗
PubMed1986

Crystal shedding in septic arthritis: case reports and in vivo evidence in an animal model.

Two cases of coexisting septic and crystalline joint disease are reported. In one patient polyarticular septic arthritis occurred simultaneously with gout and pseudogout. In a second patient septic arthritis preceded the appearance of calcium pyrophosphate dihydrate (CPPD) crystals in the joint fluid, supporting an earlier postulate that lysosomal enzymes released during sepsis lead to shedding of crystals from cartilage and synovium into the joint space. This sequence was demonstrated in a rat air pouch model of synovium, in which CPPD crystals embedded in facsimile synovial tissue were released after injection of pyogenic bacteria. Coexisting septic arthritis should always be considered when crystals are identified in inflamed joints, particularly in elderly patients with concurrent infections.

Aged↗
PubMed1985

Effect of intravenous iron dextran on rheumatoid synovitis.

Eleven patients with rheumatoid arthritis received a total dose infusion of iron dextran for anaemia. Two of them had anaphylactic reactions and the remaining nine an exacerbation of synovitis. Quantitative infrared thermal imaging was used to assess the extent and distribution of joint involvement resulting from this therapy. In all eight patients examined the 'thermographic index' increased in two or more joint areas, indicating an increase in inflammation. Small joints of the hands were maximally affected, though larger joints when previously inflamed also worsened. Uninflamed joints were rarely affected. The exacerbation of synovitis occurred 24-48 h after completion of the iron dextran infusion and corresponded with a saturating of the serum iron binding capacity. Levels of immune complexes were unaltered, implying normal reticuloendothelial function. In one further patient, reported to have synovial flares when challenged with oral ferrous sulphate, iron dextran was infused at a lower dosage. All previously inflamed joints in this patient worsened 12 h after the infusion was discontinued. Concomitant with this was an increase of lipid peroxidation products in synovial fluid and to a less extent serum. Iron dextran in vitro stimulated lipid peroxidation, but dextran alone had no effect. It is therefore suggested that iron dextran worsens synovial inflammation by promoting lipid peroxidation.

Adult↗
PubMed1984

Lymphoproliferative malignancy in rheumatoid arthritis: a study of 20 cases.

A series of 20 patients with definite or classical rheumatoid arthritis who subsequently developed a lymphoproliferative malignancy are described. The mean time between the onset of the 2 diseases was 13.2 years. A wide range of types of non-Hodgkin's lymphoma and Hodgkin's disease were found; there were no unusual histological features in the lymphomas. Although many of the patients had had gold, penicillamine, and other second-line drugs, none of them had received cytotoxic drugs, and there was no evidence that therapy was a cause of their malignancies. The likely cause of the association is a predisposition to both diseases.

Adult↗
PubMed1983

Lymphatic varices in blocked fistulous rheumatism.

Blockage of a chronic synovial fistula over the right elbow in a man with erosive, nodular rheumatoid arthritis is described. A subsequent synoviogram demonstrated gross lymphatic hypertrophy draining the joint. The implications of this finding are discussed.

Aged↗
PubMed1983

Complete heart block in rheumatoid arthritis.

We report 8 cases of complete heart block (CHB) occurring in patients with rheumatoid arthritis and review 20 similar patients previously reported. Complete heart block occurs generally in patients with established erosive nodular rheumatoid disease. It usually appears to be sudden and permanent, but progression from minor conduction delays is not uncommon. The characteristic histopathological finding is a rheumatoid granuloma in or near the AV node or bundle of His. If syncope or Stokes-Adams attacks occur, the treatment of choice is the insertion of a permanent pacemaker. The prognosis is good provided no other cardiac lesions occur, whether pericardial, valvular, or myocardial.

Adult↗
PubMedDate not supplied

Output efficiency of health maintenance organizations in Florida.

We use data envelopment analysis (DEA) to measure the relative technical efficiencies of 28 HMOs licensed to practice in the State of Florida in the autumn of 1994. Health care output measures used in the analysis are number of commercial, Medicare and Medicaid members enrolled in each plan. Inputs to the model are capital assets, total expenditures on the provision of medical services and administrative expenses. We find differences in HMO efficiency scores and loss ratios (defined as the ratio of expenses on the provision of medical services to the total expenses incurred by the organization) across individual plans. Differences in efficiency measures across model type (staff, IPA, combination) and ownership types (for-profit, not-for-profit) are small but significant: staff models and for-profits are more efficient. In a multivariate model, we also find that large HMOs are more efficient and HMOs with Medicaid patients are significantly less efficient than other HMOs.

Ambulatory Care↗
PubMedDate not supplied

Hepatotoxicity of methotrexate in rheumatic diseases.

Methotrexate-induced hepatotoxicity is well recognised in the treatment of leukaemia, psoriasis and rheumatoid arthritis. The pathological lesions are non-specific, consisting of fatty change, nuclear pleomorphism, hepatocyte necrosis, portal chronic inflammatory infiltrate, fibrosis and cirrhosis. The mechanism of liver injury is poorly understood; intracellular accumulation of methotrexate polyglutamate and consequent folate depletion are suspected to play a role. Early studies in psoriasis clearly established a relationship of the hepatic injury with the frequency of methotrexate administration. With weekly low dose therapy, however, consensus is lacking regarding the incidence of hepatotoxicity because studies have had disparate control groups, used variable dosage regimens and often failed to document pre-existing liver disease or categorised patients at risk, i.e. elderly patients, alcoholics and obese diabetics. Moreover, current methods of assessing the degree of hepatic injury are subjective, relying on interpretation by an experienced histopathologist. Preliminary evidence suggests less frequent and less severe hepatotoxicity occurs in patients with rheumatoid arthritis, probably as a result of lower methotrexate doses and better patient selection. Nevertheless, until the risk of serious liver disease is better defined it is recommended that patients have a pretreatment liver biopsy, a follow-up biopsy after a cumulative dose of 1500 mg, and then biopsies approximately every 2 years in the absence of other evidence of liver disease or risk factors.

Adolescent↗
PubMedDate not supplied

Correlation between objective and subjective measures of hand function in patients with rheumatoid arthritis.

The association between the Sollerman test of hand grip and the Sequential Occupational Dexterity Assessment (SODA) and their relationship to impairment and subjective disability measures were examined. Twenty-five patients with rheumatoid arthritis affecting their hands participated in a clinical and subjective evaluation. Clinical evaluation included the use of the two hand function instruments and measurement of finger range of motion. Subjective evaluation was done by means of a patient questionnaire comprising 20 questions from the Health Assessment Questionnaire and by visual analog scales for rating pain severity and hand function. Results confirmed a strong association between the Sollerman test of hand grip and the SODA. Both instruments were found to correlate significantly with subjectively assessed hand function. Associations between the results of the two hand function tests and subjective pain and disability assessments in global daily tasks were weak. The SODA instrument more consistently correlated to the limitations in finger motion than did the Sollerman test of hand grip. This study demonstrates that the SODA and the Sollerman test of hand grip produce similar information under controlled conditions in this patient group despite their differences in conceptual development and measurement properties. A generalized measure such as the Health Assessment Questionnaire or the pain visual analog scale alone is insufficient to represent what patients can do with their hands in daily life.

Activities of Daily Living↗