[Mechanisms of cellular detoxication, nuclear aluminum concentration and hepatocyte protection after experimental overload in rats]. / Mécanismes de détoxication cellulaire, concentration nucléaire d'aluminium et protection de l'hépatocyte après surcharge expérimentale chez le rat.

A single injection of a massive dose of Al-gluconate (4 mg.kg-1) into the saphenous vein of the rat did not provoke any ultrastructural damage in the liver cells, from 2 min. to 8 days after the injection. Al hepatocytes overload appeared only in nuclei and not in nuclei and not in lysosomes, contrarily to chronic intoxications. Nuclear Al concentration concerned only a small fraction of the quantity injected; another part was sequestered by the macrophage system after precipitation in the blood as phosphates chemically transformed during their incorporation in lysosomes. This effective detoxication mechanism which functioned probably after a first absorption by the hepatocyte, was likely to depend upon the form of gluconate and would explain the resistance of liver cells.

Detoxification of cadmium. Ultrastructural study and electron-probe microanalysis of the midgut in a cadmium-resistant strain of Drosophila melanogaster.

The midgut of a cadmium-resistant strain of Drosophila melanogaster has been studied at the ultrastructural level and by electron-probe microanalysis (EPMA). Chronic exposure to cadmium leads to a concentration of the metal in a lysosomal system developed in both anterior and posterior segments of the midgut, where it coexists with copper and sulfur. This mechanism apparently ensures a permanent cadmium detoxification and prevents cellular injury. Wild-type flies fed on a cadmium-contaminated medium manifest the same detoxification process. As a result of contamination, copper is stored along the entire length of the midgut, including a part of the middle-midgut previously named 'copper-accumulating region'. Our data demonstrate that the midgut, particularly the posterior segment, is an accumulative organ for both cadmium and copper. The involvement of the metallothionein system in the detoxification process is discussed.

Storage of Hg in the ileum of Blatella germanica: biochemical characterization of metallothionein.

Cockroach ileum has a high capability to concentrate mercury compared with other tissues. Part of the mercury contained in the soluble phase of this organ is bound to metallothionein. It is suggested that mercury of the insoluble phase is stored in lysosomes under a polymerized metallothionein form.

[Mechanisms of detoxication of cadmium by the oyster Crassostrea gigas (Mollusca, Bivalve. II. Intracellular sites of accumulation of the metal in absorbant and excretory organs]. / Recherche des mécanismes de détoxication du cadmium par l'huître Crassostrea gigas (Mollusque, Bivalve). II. Sites intracellulaires d'accumulation du métal dans les organes absorbants et excréteurs.

In oysters exposed to CdCl2 or under natural conditions (Gironde), concentrations of cadmium occur in absorbant and excretory organs, without cellular injury. The lysosomal system, involved in the storage of the metal, is implicated in detoxification processes.

[Methylmercury toxicity in insect: detection of mercury in lysosomes using electron microprobe]. / Toxicologie du méthyl-mercure chez un Insecte : mise en évidence du métal dans les lysosomes par microsonde électronique.

Intoxication of Blattella by methylmercury leads to a storage of the ingested metal within the lysosomes of ileum. Mercury is always found associated with zinc, sulphur and copper. Lysosome, therefore, intervenes in a detoxication process in Insects which have been exposed to organic mercury. It is suggested that mercury might be trapped by metallothionein.