Comparison of antiemetic effects of granisetron and palonosetron in patients receiving bendamustine-based chemotherapy.

The antiemetic effects and safety of granisetron and palonosetron against chemotherapy-induced nausea and vomiting (CINV) were retrospectively evaluated in patients with non-Hodgkin lymphoma receiving bendamustine-based chemotherapy. A total of 61 patients were eligible for this study. Before starting the bendamustine-based chemotherapy, granisetron or palonosetron were intravenously administered with or without aprepitant and/or dexamethasone. The proportions of patients with complete control (CC) during the overall (during the 6 days after the start of the chemotherapy), acute (up to 2 days), and delayed (3 to 6 days) phases were assessed. CC was defined as complete response with only grade 0-1 nausea, no vomiting, and no use of antiemetic rescue medication. Granisetron or palonosetron alone were administered to 9 and 19 patients, respectively. Aprepitant and/or dexamethasone were combined with granisetron and palonosetron in 28 and 5 patients, respectively. Acute CINV was completely controlled in all patients. Both granisetron monotherapy and palonosetron combination therapy could provide good control of delayed CINV, although the CC rates during the delayed and overall phases were not significantly different among mono- and combination therapy of the antiemetics. There was no significant difference in the frequencies of adverse drug events between the granisetron and palonosetron treatment groups. The present study showed that the antiemetic efficacy and safety of granisetron-based therapy were non-inferior to those of palonosetron-based therapy. Taken together with treatment costs, granisetron monotherapy would be adequate to prevent CINV in patients with non-Hodgkin lymphoma receiving bendamustine-based chemotherapy.

Cyclosporine enhances alpha1-adrenoceptor-mediated nitric oxide production in C6 glioma cells.

The present study was aimed at elucidating the effect of cyclosporine on phenylephrine-evoked nitric oxide (NO) production in C6 glioma cells using direct electrochemical NO monitoring. Phenylephrine (0.1-10 microM) dose-dependently stimulated NO production (0.8-12.9 microM) and this was blocked by NO synthase inhibitor, prazosin, Ca2+-depletion and Xestospongin C (a blocker of the inositol 1,4,5-trisphosphate (IP3) receptor), suggesting that the alpha1-adrenoceptor signaling pathway mediates NO production in C6 cells. Cyclosporine (approximately 10 microM) failed to evoke NO production but increased phenylephrine-evoked NO production by 20-120% of phenylephrine alone in a dose-dependent manner (1-5 microM). Xestospongin C, at a concentration which showed no effect on phenylephrine-induced NO production, significantly inhibited the cyclosporine-enhanced phenylephrine response. This finding suggests that cyclosporine may increase phenylephrine-induced NO production by accelerating IP3 receptor function in the alpha1-adrenoceptor signaling pathway in C6 cells. This enhanced NO production in glial cells may be operative for the occurrence of cyclosporine neurotoxicity including convulsions and encephalopathy.

Involvement of glial cells in cyclosporine-increased permeability of brain endothelial cells.

1. To test whether astrocytes participate in cyclosporine-induced dysfunction of the blood-brain barrier, we examined the effects of cyclosporine on the permeability of the mouse brain endothelial (MBEC4) cells cocultured with C6 glioma cells, each cell layer placed on the top and bottom of the insert membrane, respectively. 2. The presence of C6 cells remarkably aggravated cyclosporine-increased permeability of MBEC4 cells to sodium fluorescein. 3. In light of these findings, the possibility that astroglial cells could contribute to the occurrence of cyclosporine-induced dysfunction of the blood-brain barrier triggering neurotoxicity should be considered.