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Biomedical subjects

J M Thompson

Publications and source records attributed to J M Thompson.

At least 163 records · Page 9Linked to original sources
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↗
PubMed1991

Ankylosing spondylitis antirheumatic drug trials. III. Setting the delta for clinical trials of antirheumatic drugs--results of a consensus development (Delphi) exercise.

Defining the minimum clinically important difference or delta to be detected in a clinical trial depends on a number of factors including the research hypothesis, patient characteristics, the nature of the intervention and the trial design. In 2 previous studies, we have developed standardized procedures for conducting outcome measurement based on current Food and Drug Administration and European League Against Rheumatism guidelines for clinical trials in ankylosing spondylitis, and thereafter, determined the standard deviation for these outcome measures. In the final component of this series of studies, we have employed a Delphi technique to establish estimates for delta, and calculated the sample size requirements under 2 different conditions of Type I and Type II error probabilities.

Anti-Inflammatory Agents↗
PubMed1990

Performance evaluation of ISFETs and other ISE sensors for whole blood ion assay.

Performance evaluations of ion-selective field-effect transistors (ISFETs) have been carried out using both quality-control materials and whole arterial blood samples. Comparison of the results from these evaluations suggests that the whole blood evaluation may be more useful when assessing the value of particular sensors for clinical applications. The effect of outliers on the imprecision estimates is demonstrated for ISFETs and ISEs, both graphically and in the calculation of the estimates with and without the outliers present. Estimates of constant and proportional bias, against an alternative sensor, determined from the intercept and slope of the linear regression vary according to the regression method used. The bias estimates obtained for the K + ISFET against the Radiometer KNA1 using ordinary least squares regression are compared with the Deming/Mandel method and the three-group resistant line method of Tukey. The Thorn EMI ISFETs are demonstrated to have acceptable imprecision and only a small bias compared with direct ISE instruments for whole blood assay and can be considered suitable for incorporation into clinical instrumentation.

Biosensing Techniques↗
PubMed1990

Tension myalgia as a diagnosis at the Mayo Clinic and its relationship to fibrositis, fibromyalgia, and myofascial pain syndrome.

Tension myalgia is a diagnosis that has been in use at the Mayo Clinic for more than 40 years. The term describes a common muscle pain disorder that is conceptually similar to other muscle pain disorders such as fibrositis, fibromyalgia, and myofascial pain syndrome. This article outlines the history of these disorders and proposes "tension myalgia" as a term that unifies these separate diagnoses under one conceptual framework. Because the diagnostic criteria for tension myalgia have been vague, the Department of Physical Medicine and Rehabilitation at the Mayo Clinic has developed specific criteria for generalized, regional, and localized forms of this disorder. The recommended treatment approach includes reassurance, elimination of contributing factors, physical therapy to restore normal neuromuscular function, conditioning, and medications.

Algorithms↗
PubMed1989

EMG muscle scanning: stability of hand-held surface electrodes.

Electromyographic (EMG) muscle scanning measures 2-second samples of integrated muscle action potentials from individual neck and back muscles using a hand-held scanner with post-style surface electrodes separated by a fixed distance. This "scanning" technique is widely used to expeditiously assess muscle activity in the diagnosis of musculoskeletal disorders. In order to determine if the 2-second sample is sufficiently representative of electrical activity at a specific muscle site, the stability of the signal received by the hand-held scanner was measured bilaterally at six neck and back muscle sites over 40 seconds (20 2-second integration periods) in five seated subjects. Taking the overall average EMG activity as the "true" value, the mean number of 2-second integration periods required to achieve less than 5% standard error was calculated to be 1.47 for the 60 muscles tested. Only three sites required more than five integration periods. The validity of EMG scanning as a diagnostic tool is enhanced by longer integration periods.

Action Potentials↗
PubMed1989

Comparison of potassium ISFETs with the Radiometer KNA1 and the Corning 902 ion selective electrode analysers for whole blood potassium ion estimation.

Evaluation of the performance of potassium ion sensitive field effect transistors (K+ ISFETs), developed by Thorn EMI in a form suitable for mass production and for incorporation in 'near the patient' analysers, showed only very small constant and proportional biases against the Radiometer KNA1 and the Corning 902 for whole blood potassium ion estimation. Between batch imprecision tests with whole blood showed the K+ ISFET was comparable in performance to the Corning 902 but inferior to the Radiometer KNA1. The evaluation demonstrated that ISFET manufacturing technology has now reached a stage of development at which ISFETs should be considered seriously for use in clinical chemical analysers.

Calibration↗
PubMed1989

Gold-naproxen pneumonitis. A toxic drug interaction?

A patient with rheumatoid arthritis developed restrictive lung disease and blood eosinophilia. Gold pneumonitis was suspected but the patient did not improve until naproxen was discontinued as well. Lymphocyte transformation studies suggested hypersensitivity to gold. We hypothesize that naproxen unmasked and perpetuated the manifestations of gold hypersensitivity in our patient.

Alveolitis, Extrinsic Allergic↗
PubMed1989

Measurement of circulating immune complexes containing IgG, IgM, IgA and IgE by flow cytometry: correlation with disease activity in patients with systemic lupus erythematosus.

The immunoglobulin (Ig) class of the antibody component of circulating immune complexes (IC) may be an important determinant of their pathogenicity. This study reports the development of a fluorometric immunoassay, using Raji cells as solid phase component and detection by flow cytometry, for the measurement of IC containing IgG, IgM, IgA and IgE. Analytic specificity of the method was established and diagnostic sensitivity determined in groups of patients with various disorders. In a detailed study of 44 patients with systemic lupus erythematosus (SLE), elevated levels of IC were observed in the majority of patients, the prevalence of the respective Ig subclasses within the patient group being IgG-IC (93%); IgM-IC (77%); IgA-IC (59%); IgE-IC (52%). Raised levels of IC (of all classes) correlated with disease activity. Longitudinal study of a patient with acute cerebral SLE revealed elevated IC levels of all four Ig classes at presentation which fell during treatment, coincident with normalization of complement values. The biological consequences of IC of various Ig subclasses is discussed with particular reference to a possible mechanism of IgE-IC mediated tissue damage.

Adult↗
PubMed1988

Acute neurologic dysfunction after high-dose etoposide therapy for malignant glioma.

Etoposide (VP-16-213) has been used in the treatment of many solid tumors and hematologic malignancies. When used in high doses and in conjunction with autologous bone marrow transplantation, this agent has activity against several treatment-resistant cancers including malignant glioma. In six of eight patients (75%) who we treated for recurrent or resistant glioma, sudden severe neurologic deterioration occurred. This developed a median of 9 days after initiation of high-dose etoposide therapy. Significant clinical manifestations have included confusion, papilledema, somnolence, exacerbation of motor deficits, and sharp increase in seizure activity. These abnormalities resolved rapidly after initiation of high-dose intravenous dexamethasone therapy. In all patients, computerized tomographic (CT) brain scans demonstrated stability in tumor size and peritumor edema when compared with pretransplant scans. This complication appears to represent a significant new toxicity of high-dose etoposide therapy for malignant glioma.

Acute Disease↗
PubMed1988

Developmental patterns of neurite outgrowth from chick embryo spinal cord and retinal neurons on laminin substrates.

It has been previously found that neurite outgrowth on collagen substrates decreases with increasing gestational age of chick embryo spinal cord and retinal neurons in tissue culture. In the current study, laminin, polylysine and collagen were compared in their efficacy in promoting neurite extension from chick embryo spinal cord neurons aged 6-16 days or retinal neurons aged 8-16 days in ovo. The percentage of neurons with neurites and the length of the neurites were determined at 1 and 3 days in culture. There was a significant increase in neuritogenesis by laminin and polylysine compared to collagen for both spinal cord and retinal neurons. Further, in spinal cord cultures grown on a laminin substrate, there was no decline in neurite outgrowth with increasing developmental age of the neurons as was seen on collagen and polylysine. Neurite length measurements also demonstrated a significant stimulation of neuritogenesis for spinal cord, but not retinal, neurons by laminin compared to polylysine or collagen in 1-day cultures. The results demonstrate tissue-specific differences in the developmental patterns of neurite outgrowth. Retinal neurons appear to have intrinsic changes in their ability to respond to extracellular promoting factors or substrates, while spinal cord neurite outgrowth can be regulated by these extrinsic factors.

Animals↗
PubMed1988

Developmental changes in spinal cord neurite-promoting activity from chick muscle extracts.

Muscle extracts from embryonic chicks aged 10-18 days of embryogenesis produced an increase in 6-day embryo spinal cord neurite initiation. A maximal effect was observed with 18-day extract. Extracts from older chicks produced no effect. These neurite promoting factors are produced at a time in which neuromuscular junctions are forming and becoming stabilized in ovo and may act to control terminal branching, selection, and maintenance of axonal endings.

Age Factors↗
PubMed1988

Laboratory and epidemiologic assessment of a recent influenza B outbreak.

A viral surveillance system in Nashville detected an outbreak of influenza B that occurred between January and March 1986. Paired sera from 32 individuals with culture-documented influenza B illness were tested using three serologic assays. Enzyme-linked immunosorbent assay (ELISA) using purified hemagglutinin-neuraminidase and plaque neutralization detected a seroresponse in 69% and 66% of these individuals, respectively. These assays were superior to hemagglutination inhibition, which detected a 41% seroresponse. ELISA was perferred because of cost and ease of performance. A group of 286 individuals, aged 1-65 years, was studied more extensively including serologic assessment before and after the influenza B outbreak. Historical information and viral throat cultures were obtained from those with influenza-like illness during the epidemic. An influenza B infection rate (seroresponse and/or positive culture) of 31% and illness rate (infection with flu-like symptoms during the epidemic period) of 13% was demonstrated using these methods. Pre-epidemic mean serum ELISA IgG titers were lower in those with, versus those without, evidence of subsequent influenza B illness (1,541 vs. 4,311, P = .0026). Children less than or equal to 15 years of age were infected more frequently than adults (44% vs. 28%, P = .04). Fever greater than or equal to 101 degrees F was reported more frequently with influenza B than non-B illness (43% vs. 18%, P = .03). These data are useful in preparing for future epidemiologic studies of influenza B and demonstrate the value of and need for standardization of ELISA as a serologic assay for influenza B.

Age Factors↗
PubMed1988

Retinal neurons lack an acetylcholine receptor aggregating factor.

Spinal cord neurons form stable synapses on muscle cells in culture, whereas retinal neurons, an inappropriate presynaptic partner for muscle cells, form synapses that are transient. We have hypothesized that a trophic influence of neurons on muscle is involved in the stabilization of synapses. Because other neural tissues that form stable synapses on muscle cells contain factors that aggregate acetylcholine receptors (AChR) into clusters on the surface of muscle cells, it may be that these aggregation factors are necessary for stabilization of neuron-muscle synapses. Therefore, we determined the AChR-aggregating activity of retinal neurons. The results showed that cocultures of retinal neurons and muscle cells and retinal-conditioned medium do not show increases in the number of AChR on muscle cells. Conversely, spinal cord-muscle cocultures and spinal cord-conditioned medium produce increases in the number of AChR clusters. These data, along with previous studies demonstrating that retinal neurons are unable to affect the electrical membrane properties of cultured muscle cells, whereas spinal cord neurons do elicit such changes, add support to the above hypothesis of a trophic influence of neurons in synapse stabilization.

Animals↗
PubMed1988

Recurrent hypercalcemia and elevated 1,25-dihydroxyvitamin D levels in Hodgkin's disease.

Hypercalcemia has been infrequently associated with Hodgkin's disease. When seen, most cases have been attributable to skeletal invasion by disease. Herein is described a 40-year-old man with a 15-year history of Hodgkin's disease. Each of four disease recurrences was heralded by hypercalcemia occurring in the absence of bone disease or elevation of parathyroid hormone levels. Marked elevations of 1,25-dihydroxyvitamin D levels were observed that paralleled his disease course and response to therapy. The repetitive association of hypercalcemia with an elevation of 1,25-dihydroxyvitamin D in this case provides further evidence of lymphoma-associated production of this vitamin.

Adult↗
PubMed1988

Bone marrow transplantation: major advance in cancer therapy.

Bone marrow transplantation is now recognized as one of the major advances in cancer therapy occurring in the past three decades. The USAF Medical Corps recognized the future need and potential for bone marrow transplantation programs and began sponsored physician training in the late 1970's. Additionally, a bone marrow transplantation unit was designed and incorporated into the new physical plant of Wilford Hall USAF Medical Center (WHMC). The first human autologous bone marrow transplantation at WHMC was performed 6 December 1982. Since then, approximately 100 patients have undergone the procedure. As bone marrow transplantation procedures have become more extensively applied and accepted as the standard of care for selected diseases, the need for the Department of Defense (DOD) military-medical complex to provide allogeneic transplantation services has grown tremendously. This program brings the most up-to-date therapy for the treatment of many cancers to the USAF and DOD and provides the avenues for further advances in cancer therapy in the decades to come. In addition, this program has exciting potentials in the chemical warfare defense area of battlefield medicine.

Aerospace Medicine↗