Abstract
Daily determinations were made on vitamin B_<12> excreted into the urine of 19 leukemia patients in whom it was possible to continue such determiantions for a period of more than 3 weeks. It was noted that in all patients the amount of B_<12> excretion was markedly higher than normal individuals. Vitamin B_<12> excreted into the urine was determined by microbiological assay and destroyed by alkali heating. Most of the B_<12> excreted into the urine was nondialyzable. The amount of excretion by disease type showed CGL to be highest and when compared with acute leukemia the frequency for excretion of such large amounts as more than 1.0μg/day was significant at the 1% level. Study of urinary B_<12>-excretion in CGL with Busulfan administration indicated that when compared with the non-treated and remission cases, the excretion amount was markedly increased for those under treatment, being significant at the 1% level. The leukocyte turnover rate can be calculated from the amount excreted into the urine on the assumption that all the urinary B_<12> was derived from the destroyed leukocyte. The result obtained showed that these values corresponded to 15〜21% of leukocyte turnover rate which was given in the experiments using radioisotope leukocyte labelling, for both normal individuals and leukemic patients. Further, it was assumed that the destruction of leukocytes during the course of treatment of CGL until remission is of the level of 10^<12>〜10^<13>.
