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Biomedical subjects

D S Pratt

Publications and source records attributed to D S Pratt.

At least 19 recordsLinked to original sources
PubMed1996

The successful treatment of autoimmune hepatitis with 6-mercaptopurine after failure with azathioprine.

Although the treatment of choice for autoimmune hepatitis is glucocorticoids, their side effects make long-term use undesirable. Therefore, other immunosuppressive agents have been used to replace glucocorticoids in the long-term treatment of autoimmune hepatitis, including azathioprine, a purine analogue. It is derived from 6-mercaptopurine, and these two drugs are often used interchangeably. However, these drugs have different toxicity profiles and may have clinically relevant differences in immunosuppressive activity in individual patients. We report 3 patients with autoimmune hepatitis who either could not tolerate or failed to improve on azathioprine but responded well to 6-mercaptopurine.

Adolescent↗
PubMed1992

The dangers of dairy farming: the injury experience of 600 workers followed for two years.

In order to better understand the work-related injuries sustained on central New York dairy farms, we undertook a two-year population-based study of 600 farmers and farm workers on 201 dairy farms. During the observation period, 1984-1986, 151 persons had 200 injuries, giving an injury rate of 16.6%/year (166 injuries/1,000 workers/year). Men were injured more often than women (p less than or equal to 0.01). Injured workers were older (p less than or equal to 0.01), worked more hours (p less than or equal to 0.001), and had heavier workloads than noninjured workers (p less than or equal to 0.001). The growing and harvest seasons had the most injuries; winter the fewest. More than 2/3 of the injuries occurred in the afternoon. Owners/operators, often the most experienced, knowledgeable people on the farms, were most often hurt. Those working more than 60 hours/week, with greater than 30 acres under tillage/worker, had a relative risk of 2.76 compared with all other workers. The attributable risk for this group was 51%. There were two fatalities, both involved owner/operators. Our findings suggest that previous studies may have underestimated the risks faced by farmers. Dairy farming in central New York is very dangerous work. Those who own and operate these dairy farms are most often hurt and killed. Analysis of events on individual farms will be reported separately.

Accidents, Occupational↗
PubMed1992

Silo filler's disease in New York State.

Twenty new cases of Silo filler's disease (SFD) have been collected, documenting the incidence and clinical features of exposure to nitrogen oxides present in freshly filled silos. Cases of SFD were identified using a statewide computerized discharge diagnosis system. Fifteen of these were identified in the index period, allowing us to calculate an approximate annual incidence of 5.0 cases/100,000 silo-associated farm workers/yr in New York State. All cases occurred during harvest periods, with 80% in September and October. Corn silage was the gas source in 18 (90%). All cases involved young white men (mean age, 31.5 yr). The most common presenting feature was dyspnea. All victims entered a silo during the peak danger period, and only one used recommended ventilation techniques. Four cases ended in death (20% mortality). Silo filler's disease, although rare, is a potentially devastating disease involving otherwise young, healthy farm workers. It is readily prevented.

Adult↗
PubMed1991

Occupational hearing loss in New York dairy farmers.

A study of 49 randomly selected, full-time dairy farmers was performed to assess the prevalence and nature of hearing loss in this population. An age- and sex-matched group of rural, non-farmers was also studied. Medical, occupational, and recreational histories were taken and standard audiometric testing was administered. Sixty-five percent of farmers had hearing loss in the higher frequencies and 37% had losses in the mid-frequency range as compared to 37% and 12% of non-farmers respectively (p less than .01). Farmers' left ears were more severely affected. The age of the subjects and the number of years spent farming were highly correlated with hearing loss. Correlation and regression analyses supported the hypothesis that the difference in the prevalence of hearing loss between the dairy farmers and the non-farmers was due to occupational noise exposure on the farm.

Adult↗
PubMed1991

Histamine and endotoxin contamination of hay and respirable hay dust.

Three distinct samples collected from a barn in which an outbreak of respiratory problems occurred were examined for possible etiologic agents. No causal relationship could be established from the results of this study; however histamine concentrations as high as 0.5 ng/mg for bulk hay (in the absence of measurable creatinine levels) along with 6138.3 endotoxin units/mg of hay were present in the samples. Both endotoxin and histamine could be recovered from respirable hay dust. The authenticity of the histamine found in the hay was evaluated with high-performance liquid chromatography and radioimmunoassay. Histamine release caused by hay extracts was evaluated with the use of leukocytes from the farmer and a referent. Histamine is known to modulate the immune system, but the role of occupational or environmental exposure to histamine in respiratory disease is unknown.

Agricultural Workers' Diseases↗
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↗
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↗