Biomedical subjects

M Imbriani

Publications and source records attributed to M Imbriani.

129 records · Page 8Linked to original sources

PubMedDate not supplied

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). In the present study we evaluated the occupational exposure to inhalation anaesthetics during anaesthesia in 190 operating theatres of 41 hospitals in Italy. Nitrous oxide, halothane, enflurane, isoflurane were detected in the urine of 1521 exposed subjects (anaesthetists, surgeons and nurses). Significant correlations were found between the anaesthetic concentrations in urine produced during the shift (Cu) and anaesthetic environmental concentrations (CI). The results show that the urinary anaesthetic concentration can be used as an appropriate biological exposure index. The biological threshold values (urinary concentration values) proposed are the following: nitrous oxide, 15, 28 and 57 micrograms/L for an environmental exposure of 25, 50 and 100 ppm respectively; halothane, 97 micrograms/L (for an environmental exposure of 50 ppm), 6.1 micrograms/L (for an environmental exposure of 2 ppm) and 3.3 micrograms/L (for an environmental exposure of 0.5 ppm); enflurane, 145 micrograms/L (for an environmental exposure of 50 ppm), 22.7 micrograms/L (for an environmental exposure of 10 ppm), 3.7 micrograms/L (for an environmental exposure of 1 ppm); isoflurane, 5.3 micrograms/L (for an environmental exposure of 2 ppm) and 1.8 micrograms/L (for an environmental exposure of 0.5 ppm). These values apply to urine samples collected at the end of 4-hours' exposure to the anaesthetics.

Anesthetics, Inhalation↗

PubMedDate not supplied

[Technical note: proposal of a routine method of accurate measurement of urinary trans,trans-muconic acid].

A method for routine measurement of urinary trans,trans-muconic acid. A method is proposed which allows the accurate determination of urinary trans,trans-muconic acid (Ma) by HPLC with UV detection. Sample pretreatment consists of a first purification on strong anionic exchange (SAX) cartridges followed by extraction on "end capped" reversed-phase (C18-EC) ones. Purified samples are directly injected onto a chromatographic column (C18, 150 x 4.6 mm I.D., 3 microns) which is eluted with water: methanol: acetic acid (97:2:1, v/v) mixture followed by a "spike" of acetonitrile. The retention time of MA is 15 min, the coefficient of variation is lower than 3%, the limit of detection is 7 micrograms/l. The method seems suitable for accurate biological monitoring of subjects exposed to benzene.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Effects of ethanol on toluene metabolism in man.

The aim of this paper was to study the possible causes for metabolism changes due to ethanol and solvents interactions. In literature the effects of interaction between some solvents (toluene, xilene, TCE, etc.) and ethanol in acute experimental exposure are well known: the ingestion of a moderate amount of ethanol (0.8 gr/Kg) before inhalatory exposure to solvents causes the hematic levels of the solvent itself to increase and the urinary excretion of the main metabolites to decrease. In our study we have analyzed the possible effects of exposure to toluene vapours on elimination of toluene itself in urine, which is a useful biological index of occupational exposure to toluene. 5 healthy volunteers were exposed to toluene vapours (100 mg/m3 for 4 hours) with and without simultaneous ethanol consumption (0.5 g ethanol/Kg body weight) in an exposure chamber. The ethanol was ingested two minutes before entering the chamber and two hours after beginning of exposure in order to reach ethanol and toluene maximal concentrations in blood simultaneously. The blood and urine were collected at the beginning and at the end of exposure in order to measure toluene and ethanol. The analyses were performed by means of a Gas Chromatograph (GC) Hewlett-Packard 5880 A connected with a Mass Selective Detector (MSD). The obtained results show that ethanol causes a decrease in toluene metabolism: in fact, with constant environmental exposure, toluene concentration at the end of exposure increases in blood from 156 micrograms/L to 285 micrograms/L (+84%) in presence of ethanol; the same happens to the amount of toluene eliminated in urine (+45% in presence of ethanol), while the metabolized amount of toluene (hippuric acid in urine) was lower in presence of ethanol (1492 mg/g creatinine in comparison with 2251 mg/g creatinine; 37%). These results show that a moderate amount of ethanol changes toluene metabolism: this phenomenon may be an important source of error in the biological monitoring of solvent exposure.

Administration, Inhalation↗