COLCHIC-occupational exposure to chemical agents database: current content and development perspectives.

Set up in 1987, COLCHIC is a database for occupational exposure to chemical agents. Eight French regional health insurance fund (Caisse Régionale d'Assurance Maladie-CRAM) interregional laboratories and the French national research and safety institute (Institut National de Recherche et de Securite-INRS) laboratories have stored results and information from chemical agent exposure measurements on this database. More than 10 years later, 400,000 measurement results of exposure to 600 substances are now stored on COLCHIC. Utilization of data from this base is limited by the quality and absence of certain information, so a working group has been formed to develop a new data retrieval system, which takes into account recommendations formulated by the AIHA-ACGIH and European working groups. Utilization of this new coding system should allow improved description of workplace exposure conditions in the near future. This data retrieval system is currently being validated and should be used by the laboratories concerned during the course of 2001.

Asymptomatic renal-vein thrombosis in adult nephrotic syndrome ultrasonography and urinary fibrin-fibrinogen products: a prospective study.

OBJECTIVES: The diagnosis of renal vein thrombosis (RVT), a frequent complication of adult nephrotic syndrome (NS), is generally made by means of invasive methods, i.e. renal venography, venous time of renal arteriography and, more recently, computed tomography (CT). We undertook a prospective study to evaluate the use of Doppler ultrasonography (DUS) and urinary fibrin-fibrinogen degradation products (FDPU) for the diagnosis of asymptomatic RVT. METHODS: Thirty-one adult NS with non proliferative glomerulonephritis were studied. Reference procedures [(selective renal arteriography (n = 18) and renal vein CT (n = 13)] were performed blindly within a few days (48 hours in 17 patients) of renal vein DUS (search for a lack of venous flow) and measurement of FDPU (5 micrograms/min) (in 24 patients). RESULTS: DUS was not interpretable in one patient and positive in nine. Of these 9 patients, RVT was detected by reference methods in only two (sensitivity: 1, specificity: 0.75; positive predictive value: 0.22; negative predictive value: 1). Increased FDPU was observed in 4 patients, 2 of whom had an RVT (sensitivity: 1, specificity: 0.9; positive predictive value: 0.5; negative predictive value: 1). CONCLUSION: We conclude that DUS and FDPU are helpful for screening of RVT in asymptomatic NS patients; their negativity allow further radiological investigations to be avoided while positive results must be confirmed by reference methods.

A programmed feedback control of solvent vapour concentrations in experimental inhalation chambers.

This paper describes a computer-controlled system to regulate solvent vapour concentrations in experimental inhalation devices. This system consists of an exposure chamber, a bubbler with a mass flow-meter, a monitor gas chromatograph and a computer. The frequency of automatic sampling was dependent upon the retention time of test materials. Flow-rate was corrected through a computer regulated bubbler as soon as the mean chamber concentration varied by more than 2.5% of a command level. Regulation coefficients were calculated by relating the concentration of vapours sampled with adsorbent tubes to the mean peak areas given by the monitor gas chromatograph. They were then fed into the computer allowing the actual concentration to be adjusted to the command level. Deliberately induced fluctuations in the level of acetone, ethanol and trichloroethylene, either sudden or progressive, were satisfactorily corrected as were fluctuations occurring normally during repeated exposures to ethanol. Variations were generally inferior to 5% of the command level.