Combined osteolathyric effects of beta-aminopropionitrile and penicillamine on Xenopus embryos: statistical comparison with dose-addition and independence.

The combined osteolathyric effects of beta-aminopropionitrile (beta APN) and penicillamine (PNC) on developing Xenopus embryos were determined and compared with theoretical effects for the dose-addition and independence models. The testing protocol utilized a 1.2-factor matrix design that generated two single chemical and seven mixture concentration-response curves within 36 treatments. Testing was for 96-h with daily solution removal and replacement. The chi 2 goodness-of-fit test was used to compare experimental responses with theoretical responses. Response curve analyses indicated, in general, a combined effect between that expected for dose-addition and that for independence, which is a combined effect typical of chemicals acting dissimilarly.