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Biomedical subjects

D S Pratt

Publications and source records attributed to D S Pratt.

At least 37 records · Page 2Linked to original sources
PubMed1990

Presence of endotoxins in different agricultural environments.

Gram-negative bacterial endotoxins are contaminants of dusts from agricultural products. They represent a potential health hazard for farmers working in many different processes. However, the occurrence of endotoxins has not been well characterized in the various farming operations. Therefore, two farming activities with potential for generating airborne endotoxins were studied: 1) chopping of baled corn stalks or straw for bedding in New York State, and 2) oat bin unloading in Alabama. Actual airborne endotoxin levels in dusts obtained during bedding chopper operations far exceeded [90 endotoxin units (EU)/m3] the level at which acute pulmonary function decrements occur in cotton dust-exposed individuals. Endotoxin contamination of laboratory-generated dust from an oat sample likewise exceeded these levels. This study documents the presence of potentially hazardous exposures to endotoxins in two common farm processes, which expands the knowledge of airborne endotoxin exposures on the farm.

Agriculture↗
PubMed1990

Noise-induced hearing loss in randomly selected New York dairy farmers.

To understand better the effects of noise levels associated with dairy farming, we randomly selected 49 full-time dairy farmers from an established cohort. Medical and occupational histories were taken and standard audiometric testing was done. Forty-six males (94%) and three females (6%) with a mean age of 43.5 (+/- 13) years and an average of 29.4 (+/- 14) years in farming were tested. Pure Tone Average thresholds (PTA4) at 0.5, 1.0, 2.0, and 3.0 kHz plus High Frequency Average thresholds (HFA3) at 3.0, 4.0, and 6.0 kHz were calculated. Subjects with a loss of greater than or equal to 20 db in either ear were considered abnormal. Eighteen subjects (37%) had abnormal PTA4S and 32 (65%) abnormal HFA3S. The left ear was more severely affected in both groups (p less than or equal to .05, t-test). Significant associations were found between hearing loss and years worked (odds ratio 4.1, r = .53) and age (odds ratio 4.1, r = .59). No association could be found between hearing loss and measles; mumps; previous ear infections; or use of power tools, guns, motorcycles, snowmobiles, or stereo headphones. Our data suggest that among farmers, substantial hearing loss occurs especially in the high-frequency ranges. Presbycusis is an important confounding variable.

Adult↗
PubMed1990

The Bassett Farm Safety and Health Project.

The Bassett Farm Safety and Health Project was started in 1980 when Drs. May and Pratt made clinical observations on respiratory illnesses in farmers. The initial work involved the investigation of clinical syndromes associated with dust exposures and, from there, environmental dust studies. The current scope of work of The Farm Safety and Health Project includes three major components: research, education, and patient care. The research activities currently include studies into the analysis of injuries on farms, hearing loss in a randomly selected population, and estimating the annual incidence of Silo Filler's Disease in New York State. Educational activities currently include a statewide hearing conservation project, and the provision of numerous education materials for farmers and farm workers. The clinical activities include the establishment of an occupational medicine clinic in the fall of 1988, designed specifically for evaluation and treatment of agricultural workers with occupation-related illness and injuries.

Accidents, Occupational↗
PubMed1990

Hepatotoxicity due to pemoline (Cylert): a report of two cases.

Pemoline (Cylert) is an agent used to treat attention deficit disorders and other behavioral syndromes. There have, however, been three published reports of mild hepatic dysfunction in five patients coincident with pemoline therapy. We report two further cases of probable pemoline hepatotoxicity. One case involved a mild aminotransferase elevation in a 6-year-old who was on pemoline for 5 months. The second case, in an 11-year-old, developed hepatic failure with marked prolongation in prothrombin time nonresponsive to parenteral vitamin K, deep jaundice, and submassive hepatic necrosis. This patient had a long history of pemoline usage. Pharmacokinetics are briefly discussed. A spectrum of hepatic disease due to pemoline is considered and the importance of obtaining aminotransferase values before, during initiation, and throughout treatment is stressed.

Attention Deficit Disorder with Hyperactivity↗
PubMed1990

Occupational health and the rural worker: agriculture, mining, and logging.

More than 50 million Americans live in rural areas. These rural residents often work for small businesses or in the extraction industries (farming, mining, and logging). Because of the size of the businesses, the mandate of the Occupation Safety and Health Administration (OSHA) does not cover these workers and they are seldom afforded the same protection as urban workers. This review focuses on the special health problems facing farm workers, farmers, miners, and loggers. Farm workers are often ill and are affected by psychological illness, injuries, parasites, skin diseases, and the dangers of agrichemicals. Farm owners also face the hazards of stress and have very high rates of suicide. In addition, they are often injured on the job and suffer the highest rate of job related fatality of any work group. The complex farm environment presents a continuous threat to the lungs. This danger has worsened with the increased use of confinement buildings for poultry, hogs, and cattle. As farming has changed with increased mechanization, attendant medical problems have arisen. These "illnesses of innovation" are important. Mining and logging also are dangerous occupations with acute and chronic problems including respiratory illness, vascular problems, and malignancy. The decade of the 1990s must be one of increased attention to rural occupational health care and research.

Agriculture↗
PubMed1989

Levels of bacteria, fungi, and endotoxin in bulk and aerosolized corn silage.

Three samples of silage taken from the surface of a silo and from depths of 20 and 45 cm in the silo were studied for identification of the potential agents causing symptoms of organic dust toxic syndrome. The samples were examined by dilution plating before and after aerosolization in an acoustical dust generator. Aerosol samples were collected by liquid impinger and filter cassettes. The samples were examined for total aerobic bacteria, anaerobic bacteria, gram-negative bacteria, lactobacilli, listeriae, thermophilic actinomycetes, fungi, and endotoxin. Very high levels of total aerobic bacteria and fungi were found in the surface sample (up to 10(9) CFU/g in the bulk sample and up to 10(9) CFU/m3 after aerosolization), whereas the corresponding values from the deepest site were 100 to 50,000 times lower. Aspergillus fumigatus predominated among the fungi, whereas Bacillus and gram-negative organisms (Pseudomonas, Alcaligenes, Citrobacter, and Klebsiella species) prevailed among bacteria. Thermophilic actinomycetes occurred in numbers up to 10(7) CFU/g in the bulk samples, whereas anaerobic bacteria, lactobacilli, and listeriae were only few or absent. The concentration of endotoxin was high in the surface sample (up to 211.4 Endotoxin Units/mg) and about 200-fold lower in the sample from the deepest site. The results show that contact with dust from the surface of silage carries the risk of exposure to high concentrations of microorganisms, of which A. fumigatus and endotoxin-producing bacteria are the most probable disease agents.

Aerosols↗
PubMed1989

Aeroallergens in dairy barns near Cooperstown, New York and Rochester, Minnesota.

We sampled atmospheric barn air using a volumetric air sampler in ten barns near Cooperstown, NY and six barns near Rochester, MN, and, with radioimmunoassays, measured allergens of Aspergillus fumigatus, Thermoactinomyces vulgaris, Micropolyspori faeni, short ragweed, rye grass group I pollen, Alternaria (Alt-1), Dermatophagoides sp. Lepidoglyphus destructor, common insect allergen, mouse urine, rat urine, and cattle epithelium. The most abundant allergen present was A. fumigatus followed by L. destructor. This study provides initial data on barn aerobiology and demonstrates for the first time the abundance of L. destructor allergens in North American dairy barns. More comprehensive study of barns, poultry houses, confinement houses for swine, and other agricultural environments from various geographic locations is needed to define the allergen levels to which millions of farm workers are exposed each day. While most of the allergens were expected, the presence of airborne allergens reactive with antisera to Dermatophagoides suggests indirectly that substantial amounts of pyroglyphid mites are present in some barns.

Air↗
PubMed1988

The effect of whole virus influenza vaccination on theophylline pharmacokinetics.

The effect of whole virus influenza vaccination on theophylline pharmacokinetics was evaluated in 16 normal subjects. Because previous reports had suggested that influenza vaccine induces interferon production and may potentially depress hepatic metabolism of theophylline, serum interferon concentrations were monitored for 6 days after vaccination. Lymphocytes from 6 subjects were incubated in vitro with dilute whole virus vaccine (WVV) or dilute split virus vaccine (SVV) to assess their immunocompetence and the immunogenic potential of the 2 vaccine preparations. Additionally, influenza antibody response was monitored by prevaccination and postvaccination serum antibody titers in 11 subjects. No significant change in half-life, total body clearance, volume of distribution of maximal serum theophylline concentration compared to prevaccine values was observed at either 2 or 6 days after vaccination. No interferon production was detected in vivo up to 6 days after vaccination. In vitro lymphocyte interferon induction assay demonstrated mean interferon levels of 12,252 +/- 9,819 IU/ml for WVV and 888 +/- 1,180 IU/ml for SVV (p less than 0.05), demonstrating the immunocompetence of the subject's lymphocytes and confirming the greater immunogenic potential of WVV. Seven of 11 subjects (64%) showed a 4-fold rise in influenza antibody titer to at least one of the vaccine antigens. We conclude that whole virus influenza vaccine does not alter theophylline pharmacokinetics. In addition, it has greater immunogenic potential than split virus vaccine in vitro but does not induce significant interferon production in vivo. This study adds further evidence supporting the safety of the concomitant use of influenza vaccine in patients taking theophylline.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

An improved method of cell recovery following bronchial brushing.

Cytologic examination of bronchial brush specimens is effective in diagnosing bronchogenic carcinoma. A major problem is loss of cells and cellular detail associated with the direct smear technique (DST). A more recent method, the Saccomanno brush wash (SBW), uses a narrow-mouthed vial to scrape cells off the brush directly into fixative. We sampled 12 directly visualized airway tumors using standard brush technique. The same brush was then agitated in a SBW vial, which was centrifuged, the cell pellet being smeared over a predetermined area of a slide. Designated areas of each slide were counted and total malignant cells per slide extrapolated. DST slides had significantly fewer cells than SBW slides, and cellular detail was better with SBW in seven cases, DST in one case, and equal in four cases. SBW appears preferable for handling of bronchial brush specimens.

Biopsy↗
PubMed1986

Diffuse pulmonary injury following paint remover exposure.

A case of paint remover inhalation causing pulmonary edema and pleural effusions is described. Methylene chloride, an ingredient of paint removers, can cause pulmonary edema and carbon monoxide poisoning. The expanding interest in home projects involving furniture refinishing and paint removal puts a large segment of the population at risk. The implications of such exposure need to be recognized by the medical community.

Adult↗
PubMed1986

Organic dust toxicity (pulmonary mycotoxicosis) associated with silo unloading.

An acute febrile illness associated with unloading silos occurs more frequently than any other farm associated respiratory illness in mid state New York. This report describes 29 cases of organic dust toxic syndrome (also known as pulmonary mycotoxicosis) occurring in 24 men and one woman with a mean age of 29 years. In 16 instances more than one worker was exposed to the dust, and in 12 of these shared exposures more than one worker became ill. Patients presented 5.3 (SD 3.3) hours after inhalation of organic dust and mould with fever (79%), myalgia (76%), chest tightness (72%), cough (66%), and headache (59%). The mean temperature was 38.7 degrees C and the mean white blood cell count 13.2 X 10(9)/l. In contrast to patients with allergic alveolitis, nearly all these patients had normal breath sounds, chest radiographs, and arterial oxygen saturation. Tests for precipitating antibodies to farmer's lung disease antigens gave negative results in all 26 episodes in which they were done; of these, 10 had no evidence of precipitating antibodies to an aqueous extract of the silage associated with their own illness. Organic dust toxic syndrome appears to be a common and substantial respiratory hazard to young farm workers. Despite being frequently mis-diagnosed as farmer's lung, organic dust toxic syndrome is clearly a distinctly different disease process.

Acute Disease↗
PubMed1986

In vitro and in vivo changes in human complement caused by silage.

Aqueous extracts of silage samples from four farms in up-state New York were reacted in vitro with normal human serum. Hemolytic levels of complement component C3 were consumed in a dose-dependent fashion, and the four extracts differed in their relative activity rankings. Studies with chelated serum indicate that the alternative complement pathway is involved in the activation, and the active fragment C3b was demonstrated. Serum levels of hemolytic C3 and C4 in vivo were quantified before and after farmers performed their normal silo unloading operations. Although the study groups were small, suggestive evidence of in vivo complement consumption was found. IgE-related allergy did not appear to be of significance to the study groups. Complement activation may be an initiator of or contributor to adverse reactions in farmers who are exposed to airborne silage dusts.

Animal Feed↗
PubMed1985

The effect of split virus influenza vaccination on theophylline pharmacokinetics.

The effects of split virus influenza vaccine on the pharmacokinetics of theophylline and the in vivo and in vitro induction of interferon were studied in 23 volunteers. No effect on the total body clearance, half-life, or mean residence time of theophylline was found as a result of influenza virus vaccine. Additionally, no interferon activity was detected in vivo for as long as 24 h after vaccination. Finally, no production of interferon occurred in tonsil or peripheral lymphocyte cultures inoculated with split virus vaccine. We conclude that split virus influenza vaccine does not affect theophylline pharmacokinetics. In addition, we find no evidence that split virus influenza vaccine functions as an interferon inducer in humans.

Adolescent↗