Sciatic nerve regeneration through venous or nervous grafts in the rat.

This study analyses the interest of isologous venous grafts filled with saline or with Schwann cells versus nerve grafts as guides for regeneration of the sciatic nerve in 35 Wistar rats. Electrophysiological parameters (conduction velocities and distal latencies of motor responses) and the functional index of De Medinacelli were measured several times from 1 month to 1 year after surgery. An histological analysis was performed on 2 control rats and on 3 rats killed 6 or 12 months after surgery: the total number of fibers was counted on a montage photoprint of the whole nerve, and the diameters of axons and the thickness of the myelin sheath were measured on digitized images.

Characterization of non pigmented B16 melanoma cell-derived cytotoxic factors.

We analyzed and tried to characterize substance(s) responsible for cytotoxic activities detected in culture media conditioned by non pigmented B16 melanoma cells (NPB16). The different cytological tests used showed that ultrafiltrated conditioned media (CM U1 fraction) contained several cytotoxic factors with a Mw lower than 1000 Da. These factors seemed to act either directly or indirectly on cell membranes, mitochondria, on the cell cycle and on protein and DNA synthesis.

In vitro cytotoxic activity of two potential anticancer drugs isolated from Strychnos: strychnopentamine and usambarensine.

The cytotoxicity and the selective antiprotozoal activity of some Strychnos alkaloids, namely strychnopentamine (SP) and usambarensine (US) (7) led us to analyze and compare their effects with emetine (EM) by using mouse B16 melanoma cells cultivated in vitro. We observed by cytological analysis and proliferation rate studies that these substances induce analogous cytotoxic effects in B16 cells, but at different concentrations i.e.

Metalloproteinases and serine proteases activities in mixed spheroids of mouse b16 melanoma-cells and fibroblasts.

A murine B16 melanoma parental line (B16) and two clones either pigmented (B16P) or non-pigmented (B16NP) were cocultured as aggregates with mouse 3T3 fibroblasts. In vivo, these mixed aggregates developed more aggressive tumors in the mouse than corresponding pure aggregates. In vitro, the three pure cell lines secreted TIMP-2 and tissue-type plasminogen activator (t-PA) activities.

Evaluation of matrix metalloproteinases and serine proteases activities in three B16 melanoma cell lines with distinct tumorigenic potential.

Mouse B16 melanoma cells (B16, parental line) and two derived clones either pigmented (B16P) or non pigmented (B16NP) were cultured as monolayers (2D) or on agar, as aggregates (3D). The productions of gelatinases A and B (72 kDa and 92 kDa type IV collagenases) and their inhibitors (TIMP1 and TIMP2), plasminogen activators (PAs) and plasminogen activator inhibitors (PAI) were investigated. The B16 cell lines did not secrete any gelatinase, but they secreted TIMP2, tissue-type (t-PA), urokinase-type (u-PA) plasminogen activators and PAI-1 like activities.