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Biomedical subjects

R M Karr

Publications and source records attributed to R M Karr.

9 recordsLinked to original sources
PubMed1979

Inhalation challenge and pharmacologic studies of toluene diisocyanate (TDI)-sensitive workers.

Workers with "sensitivity" to toluene diisocyanate (TDI) studied in depth in an attempt to determine mechanisms of bronchial hyperreactivity. Tests included provocative inhalation challenge (PIC) with TDI and methacholine challenge. Blood samples obtained prior to and at various times after PIC were used to measure complement and split products of complement and plasma histamine levels and to determine dose-response slopes of lymphocyte cyclic adenosine monophosphate (cAMP) following stimulation with agonists. TDI-reactive individuals were all reactive to methacholine and responded to PIC with TDI by immediate, delayed, or dual bronchospastic reactions. No change in plasma histamine, total complement levels, or split products of complement were measurable. TDI reactors gave decreased lymphocyte cAMP dose response slopes to stimulation with isoproterenol, prostaglandin E1, and TDI, which suggests that impairment of adrenergic receptors may play an important role in TDI reactivity.

Aerosols↗
PubMed1978

Extraction and analysis of coffee bean allergens.

Workers in the coffee industry can develop occupational allergic disease upon exposure to dust associated with coffee manufacturing. Since controversy exists as to the source or chemical nature of these allergens, the mouse model of reaginic antibody production was used to assess the potential sources of allergens in samples obtained from a local coffee manufacturing plant. Mice were immunized with extracts of coffee dust and beans and the resulting reaginic antibody response determined by the passive cutaneous anaphylaxis reaction. Cross-reacting allergens were detected in samples of coffee dust, cleaner can debris and green coffee beans, but not in chaff or roasted coffee beans. None of the allergens detected in coffee samples cross-reacted with extract of castor beans, although these extracts contained the potent castor bean allergen. Green coffee bean allergens partially purified by gel filtration were heterogeneous with respect to molecular size, although quite similar in their reactivity with reaginic antiserum. These results suggest that the green coffee bean is the major source of allergen in coffee manufacturing plants. This allergen is heterogeneous with respect to size and heat lability, and is immunochemically different from the castor bean allergen.

Allergens↗
PubMed1978

Hypersensitivity pneumonitis and extrinsic asthma. An unusual association.

A farmer who had no prior history of pulmonary disease developed tightness in the chest of rapid onset, shortness of breath, fever, and pulmonary infiltration while farming. The symptoms of his disease worsened with repeated exposure to the dusty farm field but remitted after each of five hospitalizations. Provocative challenge with inhalation of a water-soluble extract of dust from the field reproduced both asthmatic and pneumonitic features of the disease, while administration of corticosteroids clinically controlled the entire process. The data suggest a common cause for asthma and pneumonitis in this patient.

Agricultural Workers' Diseases↗