[en] Short communication

[en] Neuroblastoma is the most frequent tumour of the childhood under the age of 5. The staging and the follow up are achieved by MIBG scintigraphy, considered as the method of reference, but sometimes difficult to interpret. The availability of monoclonal antibodies against the ganglioside GD2, expressed on the cell membrane of neuroblastoma and neuro-endocrine cancers offers novel tools that deserve to be carefully explored. We investigated four mouse monoclonal antibodies (3 lgG3: BW704, 7A4, 60C3, and the lgG1 variant of BW704: MAK704), on nude mice xenografted with a human neuroblastoma (REM). Sixty one nude mice were included. The three former MAbs provided tumour imaging, the best results being obtained with BW704, followed by 7A4 and 60C3. MAK704 was disappointing. A control antiphosphorylcholine antibody (P51-1) did not give any tumour image in the three tested mice. Scintigraphy ratios tumour/liver and tumour/muscle reached 20 and 100 with BW704, respectively, on the 10th day. Good imaging quality was already obtained from the 24th h. The tumour uptake, calculated from radioactivity countings of resected samples, reached 22 ± 3% of injected dose per gram. These results let us hope that these antibodies could also provide highly contrasted images in humans and could open the way for therapeutic applications. (authors). 18 refs., 6 figs., 1 tab

[en] Ionizing radiations have been reported as an in vitro apoptosis initiating stimulus in human lymphocytes. As the cytotoxicity of ionizing radiations and chemotherapeutic agents appears to be dependent on the efficacy of cell death induction, the manipulation of apoptosis initiation might be used as a means to suppress some pathological process. In the present study the in vivo induction of γ-ray mediated programmed cell death in humans is reported. The in vivo induction of apoptosis in peripheral blood lymphocytes (PBL) by ionizing radiations was investigated in 33 patients after each of two sessions (2 Gy and 4 Gy) of fractionated total body irradiation (FTBI) as part of their conditioning regimen before bone marrow transplantation. PBL committed to apoptosis were scored before irradiation (S1), 4 h (S2) and 24 h after 2 Gy (S3, 14-17 h after the second 2 Gy fraction). Nuclear morphology and chromatin-DNA were analysed by fluorescence microscopy immediately after blood sample withdrawal (I) and after 24 h in cell culture medium (II). (author)