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M J Leboutet

Publications and source records attributed to M J Leboutet.

81 records · Page 5Linked to original sources
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Treatment of experimental osteosarcoma tumors in rat by herpes simplex thymidine kinase gene transfer and ganciclovir.

Previous results have demonstrated the efficiency of Herpes simplex type 1 thymidine kinase (HSV1-TK) retroviral gene transfer and ganciclovir (GCV) treatment of a human osteosarcoma cell line resulting in the death of the cell population and a proximal bystander effect; therefore, we investigated gene therapy on an in vivo osteosarcoma rat model. For in vivo experiments, small fragments of tumor were grafted onto rats in a paratibial position. Seven days after the graft, packaging cells (psi CRIP-TK and psi CRIP-LLZ) were inoculated into tumor mass, followed by GCV administration. In vivo results showed the efficiency of this system that allowed the reduction of the tumor mass and prevented lung metastasis appearance, which represents the normal evolution. This type of treatment seems promising for rapidly proliferating tumors such as osteosarcoma; the lower IC50 makes this system particularly attractive as clinically doses may be of low magnitude to prevent secondary effects in patients.

Animals↗
PubMedDate not supplied

Cytokeratins expression in paragangliomas of the cauda equina.

BACKGROUND: Paragangliomas rarely involve the cauda equina region. In this location, these tumors can show misleading morphological features such as trabecular or papillary growth patterns and variable expression of cytokeratins. METHODS: We comparatively studied the immunohistochemical and ultrastructural patterns of 3 paragangliomas of the cauda equina (PCE) and of 8 paragangliomas from other sites. RESULTS: All the paragangliomas expressed neuroendocrine markers (neuron-specific enolase, chromogranin A, synaptophysin and neurofilament protein). In PCE, chief cells exhibited a strong positivity with a broad spectrum anti-cytokeratin antibody. The staining was diffuse in the cytoplasm or had a paranuclear dot-like disposition. In other sites, only one paraganglioma showed a focal expression of cytokeratins. At ultrastructural level, chief cells of PCE contained characteristic dense core granules and intermediate-sized filaments sometimes grouped in paranuclear whorls. CONCLUSION: The dual immunophenotype of PCE, paraganglionic and epithelial, must be recognized in order to distinguish these tumors from, for example, a metastasis of a neuroendocrine carcinoma. PCE are slow-growing tumors and have mostly a favorable prognosis after complete surgical excision.

Adolescent↗