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Biomedical subjects

S M Brooks

Publications and source records attributed to S M Brooks.

At least 55 records · Page 3Linked to original sources
PubMed1981

Diverse profiles of immunoreactivity in toluene diisocyanate (TDI) asthma.

Possible immunoreactivity to chemically well-characterized mono- and diisocyanate protein conjugates was reevaluated in 15 workers with TDI asthma and 17 normal (nonexposed) volunteers. Lymphocytes of nine sensitive workers were incubated with TDI human serum albumin (HSA) conjugates. Leucocyte inhibitory factor (LIF) was produced. Leucocyte inhibitory factor was also induced by hexamethylene diisocyanate (HDI) protein conjugates in four of these workers who had no prior history of exposure to HDI. Disappearance of TDI- and HDI-induced LIF was noted in several sensitive workers who were removed from further TDI exposure. Three LIF-positive workers also demonstrated positive intracutaneous reactivity to TDI-HSA. One workers had a markedly positive RAST (25.5% binding) to a monofunctional (p-tolyl isocyanate) protein reagent. These studies suggest that isocyanates have the potential for eliciting heterogeneous immune responses in certain subpopulations of exposed workers. Continued contact with isocyanates may be necessary for maintenance of specific immunity. Possible cross reactivity between TDI and HDI may be determined by new antigenic sites created by isocyanate protein interactions.

Adult↗
PubMed1980

Quillaja bark (soapbark)--induced asthma.

A 24-yr-old man developed sensitization to Quillaja bark (soapbark) dust at his work place. Within 3 mo of being employed in a factory processing Quallaja bark to produce saponin, he experienced asthma symptoms while handling the bark but only nasal symptoms on being exposed to the purified saponin. Bronchial provocation using Quillaja bark dust resulted in immediate bronchoconstriction as well as faintness, diffuse erythema, and hypotension. Radioallergosorbent test (RAST) using the pulverized crude Quillaja bark was markedly positive, and cross-reactivity between gum acacia and gum tragacanth was demonstrated using this technique.

Adult↗
PubMed1980

Determination of urinary mandelic and phenylglyoxylic acids in styrene exposed workers and a control population.

Styrene is rapidly metabolized in humans to mandelic () and phenylglyoxylic acids (P) which are excreted in urine. The present study investigates a gas chromatographic technique for measuring urinary concentrations of MA and PGA of workers exposed to styrene, compares the urinary concentrations of metabolites with time-weighted average air exposures to styrene and determines the levels of these metabolites in a population of workers not exposed to styrene. Post-shift urine specimens were obtained from a group of workers exposed to styrene in the reinforced plastic industry and from a control group. High positive correlation was found between post-shift urinary concentrations of metabolites and 8-hour TWA styrene exposure. Both MA and total metabolites (MA + PGA) gave correlation coefficient values of 0.96, p less than 0.0001. The mean MA excretion for the control groups was 6 mg/L. Determination of the concentration of these metabolites in a post-shift urine provides an effective means of estimating and monitoring human exposure to styrene.

Air Pollutants, Occupational↗
PubMed1980

Absence of airway hyperreactivity to methacholine in a worker sensitized to toluene diisocyanate (TDI).

A worker with occupational asthma due to toluene diisocyanate (TDI) was studied. Detailed immunologic studies, including those for p-tolyl isocyanate IgE antibodies and the presence of leukocyte inhibition factor for isocyanate antigen, were negative. Clinically, the subject noted more pronounced symptoms beginning on Monday morning, followed by weekend off work, and lessening of her symptoms over the working week. Methacholine challenges were negative when performed on three separate occasions, including the time when maximum symptoms were present, and again six months later, before and after bronchial challenge testing. A dose-related response to TDI was observed on bronchial provocation testing using nonirritating concentrations of TDI of 0.0165 and 0.030 ppm. This case provides evidence that the response of the airway to TDI may not always be accompanied by hyperreactivity to methacholine. Screening programs utilizing methacholine challenges may not always identify sensitized workers, since a negative methacholine challenge test does not exclude TDI sensitization.

Adult↗
PubMed1980

Familial hypersensitivity pneumonitis induced by Bacillus subtilis.

Six members of one family developed symptoms consistent with hypersensitivity pneumonitis after exposure to wood dust generated during the remodeling of a bathroom in their house. A detailed microbiologic investigation of the house and surrounding areas resulted in the isolation of 2-Bacillus species. The vegetative cell and spore extracts of these organisms were used for extensive in vivo and in vitro laboratory tests. All symtomatic members of the family demonstrated positive bronchoprovocation responses to vegetative cell extracts of B. subtilis. Two patients with clinical disease exhibited immediate positive skin tests to similar extracts. Positive lymphoproliferative responses to the vegetative cell extract of B. subtilis were observed in 4 of 5 symptomatic patients and in 1 additional patient tested with the spore form of B. subtilis. It is postulated that the abrupt appearance of this family epidemic depended on the special circumstance of continued exposure to high concentrations of B. subtilis organisms within the household. B. subtilis should be added to the list of antigens causing hypersensitivity penumonitis. Prompt recognition and elimination of this new causal agent could prevent irreversible lung damage in susceptible patients.

Adolescent↗
PubMed1978

Lifting the fog.

Explore the source record for details and available documents.

Air Pollutants↗
PubMed1978

Biochemical and physiologic changes in lungs of rats exposed to a cadmium chloride aerosol.

The purpose of this study was to examine the in vivo effects of acute exposure to a cadmium chloride aerosol on the activity of pulmonary enzymes and selected physiologic parameters that are altered by exposure to oxidant agents. Male rats were exposed for 1 hour to 0.5 per cent aerosol of cadmium chloride. At 1,5, and 11 days after exposure to cadmium chloride, exposed rats compared to control rats (data expressed as per cent of control values) had lung-to-body weight ratios of 192, 174, and 140 per cent; lung glucose-6-phosphate dehydrogenase activities of 90, 107, and 135 per cent; lung superoxide dismutase activities of 96, 101, and 132 per cent; tidal volumes of 62, 63, and 89 per cent; respiratory frequencies of 170, 145, and 108 per cent; and lung weight-specific static deflation volumes at 30 cm water of 30, 13, and 31 per cent. A zero-order clearance of cadmium from whole lung was observed, with a half-time of 27.4 days. Light microscopic examination of lung tissue revealed initial pulmonary edema on day 1 that progressed to interstitial pneumonitis on day 5, with some recovery by 11 days after exposure. The cadmium induced biochemical, physiologic, and pathologic alterations were similar to the responses observed in lungs of rats exposed to a wide variety of pulmonary irritants; thus, the changes observed may represent a nonspecific response to tissue injury.

Aerosols↗
PubMed1977

Platelet thrombopathy in asthmatic patients with elevated immunoglobulin e.

Abnormalities of second-wave platelet aggregation were demonstrated in 17 of 33 asthmatic patients in whom drug and diet intake were controlled in the hospital. Mean abnormal responses were significantly greater after epinephrine- (p less than 0.001), adenosine diphosphate-(less than 0.001), collagen- (p = 0.01), and thrombin- (p less than 0.001) induced platelet aggregation in patients with immunologically mediated asthma and serum IgE levels greater than 250 U/ml as compared to patients without immunologic factors and/or normal controls. Mean pollen-specific radioallergosorbent (RAST) binding was also significantly higher in patients with abnormal aggregation as compared to normal platelet responders (p = 0.02). Release of serotonin generally reflected abnormal aggregation patterns in asthmatic patients. Platelet factor 4 release was significantly decreased in the same groups of patients. These results suggest that the allergic state may affect platelet membrane responsiveness to multiple aggregating agents.

Adenosine Diphosphate↗
PubMed1977

Bronchial asthma of occupational origin: a review.

There are immediate benefits when one can establish the diagnosis of occupationally induced asthma. It is a man-made disease and is thus reversible. Diagnosis depends on knowledge of the source and types of exposure which can be correlated with the clinical, physiological and immunologic patterns of affected workers. The discovery of one case can often lead more readily to recognition of others. Individuals with asthma of an occupational origin should be removed from work. Equally as important is the initiation of proper industrial hygiene procedures which would improve the occupational environment and periodic medical surveillance of workers for the identification of early disease or individuals with few or no symptoms.

Allergens↗