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Biomedical subjects

P D Dyer

Publications and source records attributed to P D Dyer.

7 recordsLinked to original sources
PubMed1997

Atmospheric mold spore counts in relation to meteorological parameters.

Fungal spore counts of Cladosporium, Alternaria, and Epicoccum were studied during 8 years in Denver, Colorado. Fungal spore counts were obtained daily during the pollinating season by a Rotorod sampler. Weather data were obtained from the National Climatic Data Center. Daily averages of temperature, relative humidity, daily precipitation, barometric pressure, and wind speed were studied. A time series analysis was performed on the data to mathematically model the spore counts in relation to weather parameters. Using SAS PROC ARIMA software, a regression analysis was performed, regressing the spore counts on the weather variables assuming an autoregressive moving average (ARMA) error structure. Cladosporium was found to be positively correlated (P < 0.02) with average daily temperature, relative humidity, and negatively correlated with precipitation. Alternaria and Epicoccum did not show increased predictability with weather variables. A mathematical model was derived for Cladosporium spore counts using the annual seasonal cycle and significant weather variables. The model for Alternaria and Epicoccum incorporated the annual seasonal cycle. Fungal spore counts can be modeled by time series analysis and related to meteorological parameters controlling for seasonallity; this modeling can provide estimates of exposure to fungal aeroallergens.

Air Microbiology↗
PubMed1995

Safety of pneumococcal revaccination.

Indications for pneumococcal polysaccharide revaccination include highest-risk patients vaccinated more than six years previously, but there is controversy regarding revaccination of patients with chronic medical conditions and revaccination of the elderly. The object of the study was to investigate whether revaccination with the pneumococcal polysaccharide vaccine would cause significant adverse reactions. 151 patients were revaccinated and completed a questionnaire concerning the 72 hours after the injection. Valid data were obtained from 127 patients. Mild systemic reactions varied from 4% to 8% and local reactions varied from 40% to 60%, which is not different from the reported reaction with the initial vaccination. This profile of adverse reactions after revaccination should minimize concerns about revaccination.

Aged↗
PubMed1991

Methotrexate in the treatment of steroid-dependent asthma.

A double-blind, placebo-controlled, crossover study was designed to compare steroid requirements between placebo and methotrexate (MTX) treatment in subjects with corticosteroid-requiring asthma. Subjects began with a steroid taper and then were randomized to a 3-month trial of drug or placebo therapy. Subjects received 15 mg of MTX a week or identical placebo. A 1-month washout period was completed before the crossover trial. Symptom scores, peak flow rates, spirometry, and beta-agonist frequency were closely monitored. Ten subjects completed the study. The average dose of prednisone during the placebo-treatment period was 11.97 mg/day compared to 8.37 mg/day while subjects were taking MTX. This was a 30% reduction in daily steroid requirement (p less than 0.01). Symptom scores and spirometry did not differ between the crossover trials, and overall clinical status was not altered. Complications from MTX were mild and included anorexia, alopecia, and stomatitis. All complications resolved with dose reduction or when MTX was stopped at the end of the study. No subjects withdrew from the study because of MTX complications. Low-dose MTX significantly reduced the steroid requirement in this group of subjects with steroid-dependent asthma. This reduction in steroid requirement was obtained without altering clinical status and without significant complication.

Adolescent↗
PubMedDate not supplied

Latex-induced asthma in a dental assistant.

In this case report, latex-induced asthma is described in a dental assistant with an associated history of contact dermatitis, contact urticaria, and rhinitis. She switched to vinyl gloves, which eliminated her cutaneous symptoms, but her respiratory symptoms continued. Skin-testing to latex was strongly positive. Methacholine challenge and peak expiratory flow rates (PEFR) were abnormal during the workweek but normalized after a two-week vacation. Nebulized latex was implicated in the development of occupational asthma, and personal latex-avoidance measures did not prevent the condition.

Adult↗