RELATIVE POTENCY ESTIMATION IN DIRECT BIOASSAY WITH MEASUREMENT ERRORS*

Relative Potency Estimation in Direct Bioassay with Measurement Errors*

Bioassay and relative cytotoxic potency of cyclophosphamide metabolites generated in vitro and in vivo.

Cytotoxic potencies of cyclophosphamide, 4-ketocyclophosphamide, carboxyphosphamide, mechlorethamine (HN2), bis(2-chloroethyl)amine (nor-HN2), chlorambucil, acrolein, and cyclophosphamide metabolites generated in vivo and in vitro were determined via bioassay. Our bioassay procedure was to incubate the potential cytotoxic agent with Walker 256 ascites cells in vitro, inject these cells into hos...

Instrumental Variables Regression with Measurement Errors and Multicollinearity in Instruments

In this paper we obtain a consistent estimator when there exist some measurement errors and multicollinearity in the instrumental variables in a two stage least square estimation of parameters. We investigate the asymptotic distribution of the proposed estimator and discuss its properties using some theoretical proofs and a simulation study. A real numerical application is also provided for mor...

Relative potency estimation for synthetic petroleum skin carcinogens.

A procedure for quantitative analysis of skin carcinogenesis data, for the purpose of establishing carcinogenic potency, has been applied to observations obtained from C3H mice exposed continuously to synthetic and natural petroleums. The importance of total polynuclear aromatic (PNA) content to the skin carcinogenic activity of the crude materials was also examined. Of three synthetic petroleu...

Corrected-loss estimation for quantile regression with covariate measurement errors.

We study estimation in quantile regression when covariates are measured with errors. Existing methods require stringent assumptions, such as spherically symmetric joint distribution of the regression and measurement error variables, or linearity of all quantile functions, which restrict model flexibility and complicate computation. In this paper, we develop a new estimation approach based on co...