During the preparation of this manuscript for publication, an error was introduced into the Results section, in the fourth sentence of the paragraph beginning with "The levels of the APP-derived soluble peptides Aβ40 and Aβ42 in brains of double-transgenic mice and APP [V717I] control animals at the age of 18 weeks were quantified by specific sandwich ELISAs." The correct sentence appears below. We regret this error.In line ADAM10-mo × APP [V717I] , Αβ40 and Aβ42 were reduced by 49% and 20%, and in line ADAM10-hi × APP [V717I] , by 39% and 29%, respectively.
The problem of determining RBE values for Auger emitters incorporated into proliferating mammalian cells is examined. In general, the reference radiation plays a key role in obtaining experimental RBE values. Using survival of cultured Chinese hamster V79 cells as the experimental model, new data are provided regarding selection of a reference radiation for internal Auger emitters. These data show that gamma rays delivered acutely (137Cs) are more than twice as lethal as gamma rays delivered chronically with an exponentially decreasing dose rate (99mTc). The results confirm that the reference radiation should be delivered chronically in a manner consistent with the extended exposure received by the cells in the case of incorporated radionuclides. Through a direct comparison of the radiotoxicity of Auger emitters and alpha emitters, the high RBE values reported for DNA-bound Auger emitters are confirmed. These studies reveal that the DNA binding compound [125I]iododeoxyuridine (125IdU) is about 1.6 times more effective in killing V79 cells than 5.3 MeV alpha particles from intracellularly localized 210Po-citrate. In addition, toxicity studies with the radiochemicals 125IdU and [125]-iododeoxycytidine (125IdC) establish the equivalence of the radiosensitivity of thymine and cytosine base sites in the DNA. In view of these results, and information already available, the question of establishing quality factors for Auger emitters is considered. Finally, a method for calculation of the dose equivalent for internal Auger emitters is advanced.
Six days after tumor transplantation three daily intraperitoneal doses of 0.9% NaCl, bleomycin (BLM), or a new 111In-bleomycin complex (BLMC, 15 microCi/g body weight) were administered to glioma-bearing mice. After therapy, tumors in mice treated with 111In-BLMC were smaller than those treated with BLM. Sixteen days after the first injection tumor size for 111In-BLMC-treated mice was 560 (240-1,030) mm3, 1,980 (1,400-3,290) mm3 for BLM (P less than 0.025), and 4,830 (2,580-9,180) mm3 for NaCl (0.1 less than P less than 0.2). Thirteen days after tumor transplantation glioma-bearing mice received single intratumor injection of 0.9% NaCl, BLM, or 111In-BLMC (1.5 mCi, carried by 0.5 mg BLM/g tumor weight). The average tumor size for 111In-BLMC was smaller than that for BLM by a factor of 2.5-3.7. Host weights for these two groups were similar, and morphologic abnormalities were not found in kidney or liver.
A new '"In-bleomycin complex ("'In-BLMC) is here reported. Its radiochemical purity was 99% by thin-layer chromatography (TLC) (Rf 0.65) and in 5% agarose gel electrophoresis in 0.02 M NaHC03 it migrated toward the anode. Autoradiographs of TLC and gel electrophoresis plates showed no change on storage for 3 weeks. Urine and plasma from untreated or glioma-bearing mice after injection of " 'In-BLMC were analyzed by TLC and gel electrophoresis. Results indicated stability in vivo, nonbinding to transferrin, affinity to viable tumor, and excretion faster than "'In-BLM-B2, "'In-BLM, or 57Co-BLM. Tissue distributions 24 hr after injection of radiopharmaceutical showed activity ratios of tumor to blood, muscle, and brain of 13.1, 12.4, and 81.6, respectively, which were significantly higher than those for previously prepared 'In-BLM-B2 or "'In-BLM (except for brain, 0.05 < P < 0.1). The new "'In-BLM complex may be useful in clinical imaging and for combining radionuclide radiotherapy and chemotherapy.
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