Sulfamethazine, sulfothiazole and albendazole residue dosage in food products determined by liquid chromatography/tandem mass spectrometry.

There is a growing demand for analytical techniques for the detection of a wide variety of residues from synthetic molecules in matrices such as soil, water, air and food. These techniques have to meet the requirements of speed and sensitivity as well as the ability to handle any matrix with minimal sample clean-up. Features of mass spectrometry combined with liquid chromatography can fulfill these requirements as is shown by this work which reports the use of ion spray ionization coupled with tandem mass spectrometry for the detection of some drug residues. In particular, the direct use of existing LC methods, originally conceived for use with some other sort of detector, is demonstrated.

An in vitro investigation of the reductive metabolism of chloroform.

In hypoxic (1% pO2) and anoxic (0% pO2) incubations of CHCl3 with rat liver microsomes from PB-induced animals, no evidence of formation of monochloromethyl carbene could be found. Dichloromethane was detected as a volatile metabolite of CHCl3 in incubations with rat liver microsomes from PB-induced animals, under different oxygenation conditions (from 0% to 20% pO2). With uninduced microsomes, significant levels of dichloromethane were formed only in hypoxic (1% pO2) or anoxic incubations. The amount of dichloromethane measured was 2-6 times lower than the levels of adducts to the fatty acyl chains (FC) of microsomal phospholipid. The very low rate of dichloromethane formation suggests that the assay of expired dichloromethane is not suitable to detect the reductive metabolism of CHCl3 in vivo.

Multiple activation of chloroform in hepatic microsomes from uninduced B6C3F1 mice.

The covalent binding of 14C-label to proteins and lipids was measured after incubation of hepatic microsomes from B6C3F1 mice with different concentrations of [14C]chloroform and oxygen. The effect of reduced glutathione on the covalent binding curves was also investigated. The results indicated that chloroform is activated through three processes: the first, oxidative, shows high affinity for chloroform and low affinity for oxygen; the second, also requiring oxygen, shows low affinity for chloroform and high affinity for oxygen; and the third, showing low affinity for chloroform, is inhibited by oxygen. The covalent binding associated with the oxidative processes is very effectively prevented by GSH. The reactive metabolites formed by the O2-inhibited mechanism are not efficiently scavenged by GSH and presumably are radicals that are produced reductively. The major conclusions which can be drawn from these results are: (i) The anoxic bioactivation of chloroform can cause high levels of covalent binding. This is at variance with the current opinion that the chloroform anoxic bioactivation occurs to a negligible extent. (ii) The damages produced under the usual in vitro experimental conditions by the oxidative biotransformation of chloroform, may be strongly limited by the physiological conditions of the liver. The features of the three processes described may help in understanding the mechanism of toxicity of chloroform.

Global migration from plastic materials into olive oil and isooctane: an experimental comparison.

Global migration from several plastics (phthalate-plasticized PVC, polyurethane, polyether-polyamide copolymer and silicone rubber) into olive oil, used as a liquid simulant for fatty foods, was compared with global migration into isooctane, which has been proposed as a new fatty-food simulant. The results showed that the isooctane test (involving contact for 2 hr at 40 degrees C) is not suitable as a substitute for the olive oil test (contact for 10 days at 40 degrees C) for some types of commercial plastic materials.

[Cytogenetics in bone marrow transplantations. I. Bone marrow aplasia]. / Citogenetica in trapianti midollari. I) Aplasia midollare.

A bone marrow transplantation has been carried out in a patient with bone marrow aplasia. Besides the cytochemical and haematological tests, the cytogenetic analysis has been performed to check whether the transplantation was successful. In this case the donor was the patient's sister, so that the presence of the chimere has been used as a criteria for judging the conditions of the transplantation. the cytogenetic analysis, furthermore, is suitable to detect other chromosome abnormalities, which can represent a condition of instability of the transplanted cells and are probably an early expression of the transplanted bone marrow.