In vitro cytotoxicity and transforming potential of industrial carbon dust (fibers and particles) in syrian hamster embryo (SHE) cells.

Carbon fibers have many applications, mainly in high-tech industries such as the aviation industry. Eleven carbon samples (fibers and particles) coming from an aeronautic group were tested for their cytotoxicity and carcinogenic potential using in vitro short-term assays in Syrian hamster embryo cells. These samples were taken during each important step of the process, i.e. from the initial heating of polyacrylonitrile fibers to pure carbon fibers. They were compared to an asbestos fiber, an amorphous silica, and two commercial graphite powders. Their physical-chemical characteristics and their capacity to release reactive oxygen species (ROS) were determined. This study showed that none of the carbon samples was able to generate ROS as measured by Electron Paramagnetic Resonance analysis, and in our biological assays, they demonstrated no morphological transformation potential and low cytotoxicity compared to positive control (chrysotile asbestos).

[Biochemical and immunocytochemical study of the axonal domain of mature and immature microtubules]. / Etude biochimique et immunocytochimique du domaine axonal des microtubules matures et immatures.

The axonal domain of microtubules was analyzed using biochemistry and immunocytochemistry. High resolution isofocusing was used to study the cold-labile and cold-stable fractions of various samples: thalamus, optic nerve, sciatic nerve, brachial plexus and trigeminal nerve. The cold-labile fraction from the thalamus, i.e. from a central nervous system cell population contains 20 well-resolved isotypes as the axonal fraction from the central nervous system. The cold-stable fraction from the peripheral nervous system contains only 18 isotypes. All the cold-stable fractions are characterized by an important relative quantity of isotypes 7-9, with specific patterns tissue dependent. The cold-labile fractions are specific in both the central and peripheral nervous system. Immunocytochemistry using anti-tubulin and anti-MAP2 specific antibodies was used in PEG semi-thin sections of the embryonic tectal plate at stage E10. In the axonal profiles, cold-stable fragments of microtubules were observed. The perikaryon of the young neurons, both migrating and post-migratory, contains MAP2 as the cold-labile fractions of microtubules of the axonal process. These results suggest that; tubulin is involved in the cold-stability of the axonal domain, but this role seems tissue dependent; MAP2 is a marker of neuronal differentiation; in the growing axonal process, cold-stable fragments are present and the cold-labile pool of microtubules contain a transiently expressed protein, MAP2.