Validation Study on Five Cytotoxicity Assays by JSAAE - VIII. Details of the Neutral Red Uptake A

The inter-laboratory validation study on 5 cytotoxicity assays by JSAAE has been described in the preceding articles in this issue. Presented here are precise data and the protocols on the neutral red uptake (NR) assay with two cell lines, namely, HeLa S3 (SC) cells which are employed also in the other 4 assays, and the serumfree cultured NRCE cells. Hand-plotted dose-response curves provided unexpected information otherwise difficult to assume from calculated ED50 values and accompanying outputs from the logistic analysis program, LAP-JSAAE. The characteristics of data files from 24 laboratories were examined together with all the log(ED50) values. Variations in the negative controls in the assays revealed the level of technical competence of each laboratory. These results will supplement our understanding on the NR assay carried out in the large-scale inter-laboratory validation. . Mitsubishi-kagaku Institute of Enviromental and Toxicological Sciences, 14 Sunayama, Hasaki-machi, Kashima-gun, Ibaraki 314-02, Panapharm Laboratories Co., Ltd., 1285 Kurisaki-cho, Uto-shi, Kumamoto 869-04, Research & Development Center, Duskin Co., Ltd., 3-26-13 Esaka-cho, Suita-shi, Osaka 564, Life Science Research Information Laboratory, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako-shi, Saitama 351-01, The Center of Japan Biological Chemistry, 52 Fukue, Kaizu-cho, Kaizu-gun, Gifu 503-06, Takara Belmont Co., Ltd., 5-1 Takamatsu, Kouzai-cho, Koga-gun, Shiga 520-32, Division of Fundamental Research, KOSE Co., 1-18-4 Azusawa, Itabashi-ku, Tokyo 174, Department of Management Science, Faculty of Engineering, Science University of Tokyo, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162, Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano-shi, Kanagawa 257, Division of Radiation Medicine, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi 263, Drug Safety Laboratory, Taiho Pharmaceutical Co., Ltd., 224-2 Ebisuno, Hiraishi, Kawauchi-Cho, Tokushima-shi 771-01, The Institute of Environmental Toxicology, 4321 Uchimoriya-cho, Mitsukaido-shi, Ibaraki 303, Hakko Electric Machine Works Co. Ltd., 3055 Togura, Togura-machi, Hanishinagun, Nagano 389-08, Kurabo Industries Ltd., 14-41 Shimokida-cho, Neyagawashi, Osaka 572, Safety Evaluation Center, Central Research Laboratory, Showa Denko K. K., 1-1-1 Ohnodai, Midori-ku, Chiba-shi 267, Wako Pure Chemical Industries, Ltd., 6-1 Takada-cho, Amagasaki-shi, Hyogo 661, Japan