[Feasibility of a screening programme for lung cancer among workers previously heavily exposed to asbestos]. / Valutazione di un programma per la diagnosi precoce di cancro polmonare negli ex esposti ad asbesto.

BACKGROUND: We evaluated the feasibility and costs of a screening programme with spiral CT for the early diagnosis of lung cancer among workers previously heavily exposed to asbestos. METHODS: We invited 2000 workers, 1165 (58%) of whom accepted. Women and individuals with incomplete information were excluded; 1119 subjects (mean age, 57 years) entered the main analysis. Subjects with non-calcified lung nodules and/or dubious pleural plagues (No=338) entered a post-screening diagnostic protocol based on radiological follow-up. RESULTS: Twenty-five biopsies were performed (13 pulmonary, 9 pleural, 3 combined) revealed 5 cases of lung cancer (including 1 in stage IA). The positive predictive value of the screening test was low (31%) despite its known high sensitivity (100%) and specificity (99%). Incidence of lung cancer was similar to that registered among male residents of the Veneto Region aged 55 to 59 years. The cost of the programme was Euro 1,000 per screened subject and Euro 245,000 per diagnosis (total cost, Euro 1,181,310). The total radiation dose administered to healthy subjects was about 1,100 mSv (220 mSv per lung cancer diagnosis). CONCLUSIONS: This screening programme was ineffective due to the low participation rate, the small number of diagnoses, low predictive value, and high costs.

Acute trichloroethylene poisoning by ingestion: clinical and pharmacokinetic aspects.

Five hours after ingestion of an unknown amount of trichloroethylene (TCE) a 32-year-old woman was admitted to hospital in deep coma. The neurological condition remained unchanged for 3 days, after which there was an improvement of the central nervous system function. The concentrations of TCE in the blood, which were measured during 7 days after the solvent ingestion, gave us the opportunity to study some toxicokinetic parameters of TCE. Using a physiologically based pharmacokinetic model, the toxicokinetic parameters and blood concentrations of TCE are discussed in relation to the neurological conditions. Moreover the same model has suggested that the alveolar hyperventilation during the first 12 h following the TCE poisoning is the only treatment which may shorten the duration of the poisoning.

Benzene in the blood and breath of normal people and occupationally exposed workers.

Benzene was measured in blood and alveolar air of 168 men, aged 20-58 years, subdivided into four groups: blood donors, hospital staff, chemical workers occupationally exposed to benzene, and chemical workers not occupationally exposed to benzene. The group of exposed workers was employed in work places with a mean environmental exposure to benzene of 1.62 mg/M3 (8 hr TWA). Non-exposed workers were employed elsewhere in the same plant, with an environmental exposure to benzene lower than 0.1 mg/M3. Blood and alveolar air samples were collected in the morning, before the start of the work shift for the chemical workers. The group of exposed workers was found to be significantly different from the other three groups, both for blood and alveolar benzene concentrations. The mean blood benzene concentration was 789 ng/l in the exposed workers, 307 ng/l in the non-exposed workers, 332 ng/l in the hospital staff, and 196 ng/l in the blood donors. Apart from the exposed workers, blood benzene concentration was significantly higher in smokers than in non-smokers. The mean alveolar benzene concentration was 92 ng/l in the exposed workers, 42 ng/l in the non-exposed workers, 22 ng/l in the hospital staff, and 11 ng/l in the blood donors. Alveolar benzene concentration was significantly higher in smokers than in non-smokers in the groups of the hospital staff and non-exposed workers, but not in the blood donors and exposed workers. In the three groups without occupational exposure considered altogether, the alveolar benzene concentration correlated significantly with environmental benzene concentration measured at the moment of the individual examinations, both in the smokers (r = .636; p less than .001) and non-smokers (r = .628; p less than .001). In the same three groups and in the exposed workers, alveolar benzene concentration showed a significant correlation with the blood benzene concentration.

Breath and blood levels of benzene, toluene, cumene and styrene in non-occupational exposure.

Benzene, toluene, cumene and styrene were measured in the breath and blood of two groups of individuals. The first group included individuals belonging to a hospital staff, the second group included chemical workers who were not exposed to the abovementioned chemicals. The chemical workers were examined in plant infirmaries on the morning before the start of the workshift, and the hospital staff in the hospital infirmaries. One environmental air sample was taken in the infirmaries for each individual at the moment of the biological samplings. The environmental concentrations of benzene and styrene were significantly higher in the infirmaries of the chemical plant than in the infirmaries of the hospital. On the other hand, the environmental concentrations of toluene and cumene were not significantly different in the plant infirmaries and in the hospital infirmaries. In the hospital staff the alveolar concentrations of benzene, toluene and styrene were significantly lower than those in the chemical workers. In the hospital staff the blood concentrations of benzene, toluene and styrene were not significantly different from those in the chemical workers. Only the blood cumene concentration was significantly higher in the chemical workers. In hospital staff, smokers showed alveolar and blood concentrations of benzene and toluene that were significantly higher than those measured in the non smoker hospital staff. With reference to chemical workers, only alveolar benzene concentration was significantly higher in smokers than in non smokers.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological exposure index of styrene suggested by a physiologico-mathematical model.

We used a physiologico-mathematical model to study the biological exposure index of styrene correlated to the Threshold Limit Value (TLV) suggested by the ACGIH for 1986-87. This model allows the solvent concentrations in blood, alveolar air, fat tissue, and in other biological media to be estimated and simultaneously the kinetics of its metabolites to be followed when a specific exposure is settled. The comparison between the results obtained from the mathematical model and the numerous research projects documented in the literature suggests a reciprocal validation. Moreover, some biological parameters (particularly the alveolar ventilation) can explain the variability of results obtained from studies concerning the solvent pollution of the factories, which used biological monitoring. The ranges of styrene concentrations in blood and alveolar air and the urinary concentrations of its metabolites (mandelic and phenylglioxylic acids) are discussed in connection with the exposure at 215 mg/m3. Important differences correlated to the definition of set-levels of TLV and Biological Exposure Index (BEI) have been found: particularly the TLVs lead to different solvent uptakes according to some biological parameters; the BEI can better explain the individual solvent uptake and body burden.

Physiologicomathematical model for studying human exposure to organic solvents: kinetics of blood/tissue n-hexane concentrations and of 2,5-hexanedione in urine.

The physiologicomathematical model with eight compartments described allows the simulation of the absorbtion, distribution, biotransformation, excretion of an organic solvent, and the kinetics of its metabolites. The usual compartments of the human organism (vessel rich group, muscle group, and fat group) are integrated with the lungs, the metabolising tissues, and three other compartments dealing with the metabolic kinetics (biotransformation, water, and urinary compartments). The findings obtained by mathematical simulation of exposure to n-hexane were compared with data previously reported. The concentrations of n-hexane in alveolar air and in venous blood described both in experimental and occupational exposures provided a substantial validation for the data obtained by mathematical simulation. The results of the urinary excretion of 2,5-hexanedione given by the model were in good agreement with data already reported. The simulation of an exposure to n-hexane repeated five days a week suggested that the solvent accumulates in the fat tissue. The half life of n-hexane in fat tissue equalled 64 hours. The kinetics of 2,5-hexanedione resulting from the model suggest that occupational exposure results in the presence of large amounts of 2,5-hexanedione in the body for the whole working week.