A similar expression would result if different dilution steps were used for each ampoule or different coefficients of variation were used for different dilution steps or solutions. The sum above (S2) would include terms (1 d)2(Cv2 + CA2) with appropriate values of d, Cv and CA for each step. If R is the estimate of the relative potency computed for an assay, then for known relative potency, r, ...

The induction by chemical carcinogens of resistance to terminal differentiation in cultured mouse keratinocytes has been proposed to represent a cellular change associated with the initiation phase of skin carcinogenesis. Previous results with this culture model indicated that the number of differentiation-resistant foci was correlated with the dose and known potency for several chemical carcin...

The effects of agars on the determination of the potency of polymyxin B sulfate by the agar plate diffusion method were investigated. The results showed that there were significant differences in the potency of polymyxin B sulfate between agars produced by different manufacturers. In order to investigate this phenomenon, two major components of polymyxin B sulfate, namely, the polymyxin B1 and ...

Nonylphenol belongs to the most investigated xenohormones acting at the estrogen receptor. Technical nonylphenol contains approximately 20 para-substituted isomers. Because of limitations in testing and quantifying all 20 isomers in the mixture, the linear form, 4n-NP, is often used as a reference substance, even though it is not present in the technical mixture. Here, we report on the synthesi...

The induction by chemical carcinogens of resistance to termi nal differentiation in cultured mouse keratinocytes has been proposed to represent a cellular change associated with the initiation phase of skin carcinogenesis. Previous results with this culture model indicated that the number of differentiation-resist ant foci was correlated with the dose and known potency for several chemical carc...