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Ichikawa T, Ichikawa Y, Isaacs JT.Ichikawa T, et al. Among authors: isaacs jt.Proc Natl Acad Sci U S A. 1992 Mar 1;89(5):1607-10. doi: 10.1073/pnas.89.5.1607.Proc Natl Acad Sci U S A. 1992.PMID: 1542651Free PMC article.