[Mercapturates and biologic monitoring: benzene].

S-Phenylmercapturic acid (PMA), a urinary metabolite which derives from the conjugation of benzene epoxide with glutathione, has been recently included in the list of the biological markers of benzene exposure. We have evaluated the urinary PMA levels in 145 workers exposed to benzene and in 87 subjects not occupationally exposed to the solvent (45 smokers and 42 non-smokers). In non-exposed persons, the background PMA excretion was nearly constant during one day (urine samples were collected in the morning, afternoon, and evening) and in smokers the mean PMA levels were higher than in non-smokers (9.

[Heat exchange between human body and environment (theoretical bases of physiological measurement and evaluation)].

In the first part of this report the theory of the heat exchange between human body and external environment is developed. In particular, the problems concerning energy expenditure and heat production [metabolic heat] during physical activity, the heat exchange between internal organs and body surface, and its elimination are considered. Proposal of heat exchange equations (in case of conduction, convection, evaporation, radiation transport) are made, and the involved parameters and constants are indicated.

Trans,trans-muconic acid, a biological indicator to low levels of environmental benzene: some aspects of its specificity.

Background: The specificity of trans,trans-muconic acid (MA) as a biomarker of exposure to low benzene levels and the role of sorbic acid (SA) as a confounding factor were evaluated. MA, a urinary ring-opened metabolite of benzene, has been recently proposed for the biological monitoring of populations exposed to low levels of this chemical. The usual presence of MA in urine of non-occupationally exposed people is generally attributed to benzene world-wide contamination (mainly by smoking habits, urban pollution, and maybe by food contamination).

The biological monitoring of inhalation anaesthetics.

The biological monitoring of inhalation anaesthetics. Occupational exposure to inhalation anaesthetics is an undesired consequence of the work in the operating theatre. Anaesthesia is currently practised using nitrous oxide associated with one or more potent anaesthetics (halothane, enflurane, isoflurane).

Partition coefficients of methyl tert-butyl ether (MTBE).

The knowledge of the partition coefficients between the air and arterial blood and between the blood and the different physiological compartments of the body are essential to the mathematical modelling of the respiratory uptake and elimination of toxic vapours. Partition coefficients of methyl tertbutyl ether (MTBE) in saline, olive oil, urine and human blood, and various rat tissues were calculated after gas-chromatographic quantification of MTBE in the air phase. The blood/air, urine/air saline/air, fat/air and oil/air partition coefficients (lambda) are respectively: 20.