Description of a specific bronchial provocation test for the diagnosis of occupational asthma due to platinum salts.

BACKGROUND: Occupational exposure to platinum salts may cause the onset of skin and respiratory disorders with an IgE-mediated allergic mechanism. The diagnosis of occupational asthma due to platinum salts was, in a small number of cases, achieved also via occupational specific bronchial provocation tests (sBPT), which until now were conducted by pouring platinum salt dusts from one tray to another or by direct aerosoling of hexachloroplatinate solutions into the patient's airways. METHODS: Here we describe an original occupational sBPT based on atomization of solutions of ammonium hexachloroplatinate, at increasing concentrations, in a 5 m3 challenge room: the starting solution is a 1:100 dilution of the preset threshold of the patient's skin reactivity to the substance. In the absence of a bronchoconstrictive response, the following concentration is atomized (each time 10 times higher than the previous one), until the maximum concentration, 10(-2) M, is reached. The patient is not in the challenge room during atomization of the solutions, but enters when this operation has been completed and remains there for 15 minutes, unless he/she shows signs of respiratory trouble before that time. After each exposure, the patient is clinically monitored, with respiratory function tests at preset times, until at least 8 hours after the end of the exposure. RESULTS AND CONCLUSIONS: The test allowed identifying a respiratory hypersensitivity specifically to platinum as cause of asthma in two precious metal workers, with the onset of immediate bronchospasm in one patient and biphasic bronchospasm in the other. Compared to the sBPT by pouring a mixture of platinum salt dusts from one tray to another, the method we designed offers a better standardization of bronchial stimulation and, compared to direct aerosoling of hexachloroplatinate into the patient's airways, it has the advantage of reproducing the respiratory risk conditions occurring in the workplace and offers better safety guarantees for the patient, since it reduces the risk of onset of serious asthmatic or even systemic responses in subjects highly hypersensitive to this metal.

Cobalt exposure in 'hard metal' and diamonds grinding tools manufacturing and in grinding processes.

Cobalt is considered to play a major role in the development of 'hard metal' interstitial lung disease, asthma and other adverse health effects. A survey of occupational exposure of workers is a fundamental step to obtain exposure-response information and for preventive action. Process related exposure assessment was performed before and after technical control in small and medium size factories in a large surveillance programme. Cobalt containing airborne dusts were sampled by performing multiple measurements at the workplace of each process in which the types of job and duration of exposure were similar. Samples were analyzed by atomic absorption spectroscopy. Very high exposure levels encountered before technical control were significantly lowered with efficient local exhaust ventilation plant in 'hard metal' and grinding processes, but sometimes the TLV of 0.05 mg/m3 were exceeded. In the manufacture of grinding tools, major steps in cobalt control by local ventilation was not able to keep exposure below the TLV; exposures from 0.12 to 0.75 mg/m3 were recurrent and these need control strategies.

Rechallenging subjects with occupational asthma due to toluene diisocyanate (TDI), after long-term removal from exposure.

OBJECTIVES: Aims of this study were to define (1) whether toluene diisocyanate (TDI) bronchial hyper-responsiveness persists in subjects with occupational asthma after long-term cessation of exposure; (2) whether evolution of specific bronchial TDI sensitization and symptoms and functional abnormalities of asthma were coincident, and (3) the determinants at the time of diagnosis of patients' outcome. METHODS: Twenty-five nonatopic spray painters with occupational asthma due to TDI were re-examined 58 +/- 7 (46-73) months after removal from exposure. On both examinations, the severity of asthmatic symptoms and the need for antiasthma treatment over the past 12 months were graded and lung function tests, measurement of airway responsiveness to methacholine (PD(20)), circulating total IgE and TDI-HSA specific IgE, skin tests with common inhalant allergens and specific bronchial challenge with TDI were carried out. RESULTS: Seven subjects were still TDI-reactors and 18 lost reactivity to it. All persistent reactors had still asthma and their symptom score, medication score, FEV(1), PD(20) and serum IgE were unchanged between assessments. In the 18 subjects no longer responsive to TDI, 8 had still features of asthma: their symptom and medication score had improved significantly, but FEV(1), PD(20) and serum IgE had not significantly changed; the other ten patients no longer reactors to TDI were also asymptomatic and their PD(20) had become normal. The duration of symptomatic exposure to TDI was the only feature at diagnosis that differentiated patients with persistent TDI airway hyper-responsiveness and asthma from those who were no longer responsive to TDI but still asthmatic and those who were no longer responsive to TDI and no longer asthmatic (4 +/- 1.6; 2.1 +/- 0.8; 0.6 +/- 0.3 years, respectively; p < 0.001). CONCLUSION: our study demonstrates that airway sensitization to TDI and symptoms and functional airway abnormalities of asthma can persist for years after cessation of exposure and may have different outcome. If avoidance of the offending agent takes place within few months after the development of symptoms, remission of asthma and of TDI bronchial hyper-responsiveness can occur, whereas waiting for years makes it too late to cure asthma and, in the end, to reverse specific sensitization.

Bronchial provocation testing in the diagnosis of occupational asthma due to latex surgical gloves.

In sensitized subjects, provocation tests to latex may induce severe systemic reactions and even anaphylactic shock. It is probable that part of the risk is due to the difficulty in grading the stimulating dose and in starting from very low levels of exposure. To identify the aetiological agent of work-related asthma in four nurses with previous allergic contact urticaria to latex surgical gloves dusted with cornstarch powder, we performed a specific bronchial provocation test study, based on exposure on three different days to nonpowdered latex surgical glove extract, powdered latex surgical glove extract and cornstarch powder extract, respectively. Extracts were nebulized in increasing concentrations in a 7 m3 challenge room, in the absence of the patients. The initial extract concentration was a tenfold dilution of the predetermined skin test end-point in the individual undergoing challenge, and the highest concentration was the undiluted extract. After exposure, the patients' forced expiratory volume in one second (FEV1) was monitored for 2 h. If FEV1 decreased by at least 15%, the next scheduled exposure was not carried out and FEV1 was monitored over a period of 24 h. Whereas nebulization of cornstarch powder extract caused no bronchial reaction in the patients, nebulization of nonpowdered latex surgical glove extract induced immediate bronchoconstriction in two subjects as an undiluted solution, and nebulization of powdered latex surgical glove extract induced immediate bronchoconstriction in all subjects at the 1:10 dilution. No systemic reaction was elicited by the bronchial provocation challenges. Our results demonstrate that airborne powder from latex gloves can be an inhalative occupational hazard.(ABSTRACT TRUNCATED AT 250 WORDS)

Dimethylformamide risk. An evaluation in the production of artificial organic leather.

This study aimed to evaluate the exposure to DMF during the different stages in the production of synthetic polyurethanic leathers. Environmental surveys and biological surveillances were carried out in order to classify the working areas and the tasks of the employees as regards DMF-risk. Design improvements to reduce, as far as possible, environmental pollution are discussed.