Effects of the sites of injection of aminoguanidine sulfate on developing eggs

Cardiotoxicity of trastuzumab (herceptin) in chick embryos

The cardiac toxicity of trastuzumab was studied in chick embryos. Fertilized eggs of White Leghorns were incubated and investigated. Trastuzumab 5 mg/egg (low dose) or 15 mg/egg (high dose) was injected into the air sac of a fertilized egg on the 16th day of incubation. Electrocardiograms (ECGs) were recorded 0 to 60 min after the injection. After low dosing of trastuzumab, the heart rate was not different compared with the control. However, the heart rate was significantly decreased by high dosing of trastuzumab. In addition, arrhythmia was produced by high dosing of trastuzumab. These findings indicate that trastuzumab has a marked dose- and time-dependent influence on the heart rate in chick embryos.

Aminoguanidine inhibits cell proliferation by prolongation of the mitotic phase

Aminoguanidine has been reported to increase mitotic cells in the liver and to retard the development in chick embryos. In this study, in vitro effects of aminoguanidine on mammalian cells, BRL-3A (from normal rat liver) and HeLa-S3 (from human cervical cancer), were examined. When cells were incubated with varying concentrations of aminoguanidine for 48 h, the cell growth was inhibited at high concentrations of aminoguanidine, without cell death; the 50% growth-inhibitory concentrations (IC50) against BRL-3A and HeLa-S3 cells were 4.6 and 2.2 mg/ml, respectively. After culture with aminoguanidine for 24 h, the proportion in the G2/M-phase in both cell lines was increased, but the proportion in the G1-phase was decreased, and the rate in the S-phase was slightly increased at low concentrations of this agent and decreased at high concentrations. The effects of aminoguanidine on the increase in the G2/M-phase in HeLa cells were dose-dependent. In synchronized HeLa cells, aminoguanidine clearly prolonged the M-phase. From these results, it is confirmed that aminoguanidine inhibits cell proliferation by prolonging the M-phase in the cell cycle in mammalian cells as well as chick embryo liver cells.