Sensitivity of common onion (Allium cepa L.) and faba bean (Viciafaba L.) to cadmium (Cd) stress was investigated using genotoxicity endpoints. Simultaneously, the antioxidative stress enzymes (guaiacol peroxidise and catalase) and lipid peroxidation [malonaldehyde MDA) conten] were investigated in the plants exposed to Cd in solution. The endpoints screened for genotoxicity included chromosomal aberrations, micronuclei frequency and mitotic frequency. Additionally comet assay was performed for DNA fragmentation. Evan's blue uptake by the root meristems as a cell death parameter served as indicator of cytotoxicity. The results indicated that exposure to Cd induced dose-dependent increase in chromosomal aberrations, DNA fragmentation and micronucleus frequency in both A.cepa and V. faba. The enzymes guaiacol peroxidase (GPX) and catalase (CAT) activities increased in both the plants and were higher in V. faba. A positive correlation between the activity of GPX and CAT and MDA content was recorded at all concentrations of Cd. Regarding sensitivity, our results showed that V. faba is more sensitive plant than A. cepa towards Cd -induced toxicity. Higher genotoxicity level correlated to the increased level of oxidative stress in root tissues. This was likely to be an important cause of Vicia plant to be less tolerant than Allium.

The pharmacokinetics of scorpion venom and its toxins has been investigated in experimental models using adult animals, although, severe scorpion accidents are associated more frequently with children. We compared the effect of age on the pharmacokinetics of tityustoxin, one of the most active principles of Tityus serrulatus venom, in young male/female rats (21-22 days old, N = 5-8) and in adult male rats (150-160 days old, N = 5-8). Tityustoxin (6 µg) labeled with 99mTechnetium was administered subcutaneously to young and adult rats. The plasma concentration vs time data were subjected to non-compartmental pharmacokinetic analysis to obtain estimates of various pharmacokinetic parameters such as total body clearance (CL/F), distribution volume (Vd/F), area under the curve (AUC), and mean residence time. The data were analyzed with and without considering body weight. The data without correction for body weight showed a higher Cmax (62.30 ± 7.07 vs 12.71 ± 2.11 ng/ml, P < 0.05) and AUC (296.49 ± 21.09 vs 55.96 ± 5.41 ng h-1 ml-1, P < 0.05) and lower Tmax (0.64 ± 0.19 vs 2.44 ± 0.49 h, P < 0.05) in young rats. Furthermore, Vd/F (0.15 vs 0.42 l/kg) and CL/F (0.02 ± 0.001 vs 0.11 ± 0.01 l h-1 kg-1, P < 0.05) were lower in young rats. However, when the data were reanalyzed taking body weight into consideration, the Cmax (40.43 ± 3.25 vs 78.21 ± 11.23 ng kg-1 ml-1, P < 0.05) and AUC (182.27 ± 11.74 vs 344.62 ± 32.11 ng h-1 ml-1, P < 0.05) were lower in young rats. The clearance (0.03 ± 0.002 vs 0.02 ± 0.002 l h-1 kg-1, P < 0.05) and Vd/F (0.210 vs 0.067 l/kg) were higher in young rats. The raw data (not adjusted for body weight) strongly suggest that age plays a pivotal role in the disposition of tityustoxin. Furthermore, our results also indicate that the differences in the severity of symptoms observed in children and adults after scorpion envenomation can be explained in part by differences in the pharmacokinetics of the toxin.