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Development and loss of toluene diisocyanate reactivity: immunologic, pharmacologic, and provocative challenge studies.

Toluene diisocyanate (TDI) sensitivity accompanied by nonspecific bronchial hyperresponsiveness occurs in approximately 5% of occupationally exposed workers. We report the case of a 32-yr-old worker followed longitudinally after removal from isocyanate exposure. TDI reactivity was lost 11 mo after removal from exposure and nonspecific bronchial hyperresponsiveness resolved after 17 mo. Bronchial reactivity to radishes (Raphanus sativus), which developed concurrently with TDI reactivity, was lost 2 yr later. Immunopharmacologic results show that the worker's initial decreased ability of lymphocytes to produce cyclic AMP returned to near normal after 2 yr. IgE antibodies to a human serum albumin tolyl monoisocyanate conjugate were still present at this time.

Adult↗

Detection of immunologically sensitized isocyanate workers by RAST and intracutaneous skin tests.

Antibody estimations by RAST were performed on 621 partially selected isocyanate workers whose case histories were well-documented. Two hundred forty-seven of the workers were clinically suspected to be sensitized to isocyanates since they had suffered from occupationally related recurrent asthmatic attacks, chronic obstructive lung diseases, bronchitis, rhinitis, conjunctivitis, cutaneous hypersensitivity reactions, and/or fever. RAST studies with seven different isocyanates conjugated to human serum albumin (HSA) demonstrated that 14% of these symptomatic subjects had significant levels of specific-IgE antibodies. On the other hand, only one of the 374 asymptomatic workers had such antibodies. In contrast to toluene diisocyanate (80:20% mixture of 2, 4 and 2, 6-isomers, if not otherwise mentioned)-HSA, a toluene diisocyanate-ovalbumin conjugate exhibited no antigenicity in nearly all of the cases. Intracutaneous skin testing with five different isocyanate-HSA conjugates performed in 203 workers produced immediate-type wheel-and-flare reactions in 14 of the 53 symptomatic persons but in none of the 150 asymptomatic probands. There was a good overall correlation between RAST and skin test results. Our findings provide strong evidence for IgE-mediated sensitization to isocyanates in a subgroup of the subjects with isocyanate-induced diseases. By means of RAST and/or skin testing these immunologically sensitized persons can be identified.

Antibodies, Anti-Idiotypic↗

Respiratory muscle function in patients with asbestos-related pleural disease.

The effect of asbestos-related pleural disease (ARPD) on the generation of maximum respiratory pressure was investigated in 11 male patients with ARPD mean age 57 years, range 45-74, and mean duration of asbestos exposure of 9.9 years, range 5-16. There were three smokers, seven ex-smokers and one non-smoker. Breathlessness ranged from grade 1-3 on the MRC score. The extent of pleural disease was calculated using a score based on the ILO score for pleural disease. Full respiratory function tests, global respiratory muscle strength and diaphragmatic strength were assessed. Respiratory muscle strength, including diaphragm strength, was normal. Recoil pressure was high or at the upper limit of normal in four patients and correlated with chest radiograph score for pleural disease (r = 0.65, P < 0.02). There was no difference in either global respiratory muscle or diaphragmatic strength between patients with and without involvement of one or both costophrenic angles or between patients with mild or severe breathlessness. We conclude that respiratory muscle strength is not importantly reduced in ARPD, and it is unlikely that weakness contributes to breathlessness in these patients. By contrast reduced chest wall compliance is likely to be an important factor in breathlessness in some cases.

Aged↗

Investigation of a respiratory disease associated with an air-conditioning system.

This paper describes the investigation of respiratory disease presenting in a group of men employed on the printing floor of a factory. The air-conditioning units supplying this floor were found to be contaminated with a variety of micro-organisms. The specific cause of the disease was not identified but an alteration in the system of humidification led to the complete resolution of symptoms.

Aged↗

Tidal breathing parameters in the first week of life and subsequent cough and wheeze.

BACKGROUND: Assessment of tidal breathing parameters may be a useful method of predicting respiratory problems in early childhood. Low values of TPTEF/TE (the ratio of the proportion of time to reach peak tidal expiratory flow to total expiratory time) outside the neonatal period have been significantly related to respiratory tract illness with wheezing in boys in the first year of life. METHODS: TPTEF/TE measurements in the perinatal period were evaluated in nonsedated infants and the predictive value of this early measurement for subsequent respiratory morbidity during infancy was assessed. Flow during tidal breathing was measured while the infant slept quietly in a plethysmograph using a Fleisch pneumotachograph inserted into an infant face mask. Recruitment continued until traces from 60 infants with 10 consecutive flow curves without artefacts were obtained. In addition, plethysmographic measurements of airway resistance (Raw) and thoracic gas volume (TGV) were measured and specific conductance (sGaw) calculated. Parents recorded their infant's cough and wheeze during the first 12 months of life. RESULTS: Sixty five measurements were made in 60 infants with a mean age of two days and gestational age of 40 weeks. Two observers separately calculated TPTEF/TE ratios on 25 traces randomly selected from the pool of 60. The mean difference between the two observers was -0.004 (limits of agreement 0.048 to -0.056). Thirteen infants became symptomatic (wheeze, with or without cough); their median TPTEF/TE ratio (0.349) was significantly lower than the rest of the cohort (median 0.412) and they also had significantly higher Raw and lower sGaw. The positive predictive value of a low TPTEF/TE ratio, however, was only 41%. CONCLUSIONS: These results suggest that the use of this test in the prediction of future respiratory disease in an individual is limited.

Cohort Studies↗

Effects of human exposure to atmospheric epsilon-caprolactam.

There is little published information on the human toxicology of epsilon-caprolactam, the monomer precursor of nylon 6. This paper reports an investigation of a group of eight workers who had been chronically exposed to atmospheric caprolactam levels of around 70 times the current ACGIH threshold limit value (TLV). No evidence of systemic toxicity was found, although all workers showed a greater or lesser degree of skin change in the form of peeling and/or fissuring.

Adult↗

Clinical significance of pulmonary function tests. Alterations in pulmonary function following respiratory viral infection.

Respiratory viral illness is a major cause of morbidity in both adults and children. This report focuses on both the acute and chronic effects on respiratory function of these ubiquitous infections. Infant airways are particularly vulnerable due to the relatively low conductance in immature peripheral airways. Bronchiolitis, caused predominantly by respiratory syncytial virus, is the most important of these viral illnesses and is emerging as a major risk factor for the subsequent development of obstructive airway diseases in adults, possibly by interference with normal alveolar proliferation. The basic pathogenic mechanism involved in adult respiratory viral infection is bronchial hyperreactivity, presumably secondary to epithelial damage and resultant sensitization of rapidly adapting airway receptors. In addition, there may be virus-related alterations in the autonomic and humoral regulation of airway tone. Viral infections may alter the effects of common air pollutants on respiratory function.

Adult↗

Respiratory allergy to algae: clinical aspects.

A comprehensive investigation was done to evaluate the allergenic algae in the Delhi area. Results of 4,000 skin tests performed on 400 patients suffering from naso-bronchial allergy and 300 skin tests on 30 healthy persons with 10 common algae isolated from the Dehli atmosphere are presented and compared. Positive skin reactions (1+ to 3+) to algae extracts ranged from 25.7% with Lyngbya major extract to 1.7% with Oscillatoria simplicissima extract; in healthy non-allergic volunteers there were no positive skin reactions. The Prausnitz-Küstner (PK), bronchial provocation and conjunctival tests were negative in patients with negative skin reactions; in patients with positive skin reactions PK was positive in 70.9%, bronchial provocation in 50% and conjunctival in 48.5%. Levels of total IgE in patients with naso-bronchial allergy were higher, ranging from 1,225 international units per ml to 1,550 international units per ml, while in healthy volunteers the values were less than 885 international units per ml.

Allergens↗