HPLC-MAXPLOT UV检测法测定血清中丹那唑及其代谢产物

本文建立了同时测定人体血清中丹那唑(Ⅰ)及其主要代谢产物2-羟甲基妊娠素(Ⅱ)和其它代谢产物妊娠素(Ⅲ)的高效液相色谱法。方法用YWG C18柱并以甲醇—水(74:26)作为流动相,应用紫外最大吸收作图法(maxplot)检测技术,以UV 285,240nm分别测定Ⅰ,Ⅱ和Ⅲ。使原型药和代谢产物都达到较高检测灵敏度。同时对方法的专一性、准确性和精密度等方面进行了评价,并应用于临床监测。     

Inosine monophosphate dehydrogenase and myeloid cell maturation

In previous studies of purine ribonucleotide metabolism in the human myeloid leukemia cell line HL-60, we observed that there is a down- regulation of guanine ribonucleotide biosynthesis from the central intermediate, inosine monophosphate (IMP) and a depletion of intracellular guanosine triphosphate (GTP) and guanosine diphosphate (GDP) pools that occur during the induced maturation of these cells. We also found that inhibitors of IMP dehydrogenase, the enzyme that catalyzes the first step of guanylate synthesis from IMP, are potent inducers of HL-60 maturation. Because of these observations we specifically investigated the activity of IMP dehydrogenase in HL-60 cells and in a new inducible human myeloid leukemia cell line, RDFD2- 25, both during maintenance culture and during induced maturation of the cells. Enzyme activity was examined directly in cell extracts with a radiometric assay that measures free 3H2O formed from [2-3H] IMP during the conversion of IMP to XMP. Uninduced HL-60 and RDFD2 cells in maintenance culture were found to have high levels of IMPD activity (5.2 to 5.7 pmol IMP metabolized/10(7) cells/min) compared with normal neutrophils and monocytes that had been purified from blood (less than 1.5 pmol IMP metabolized/10(7) cells/min). However, when HL-60 and RDFD2-25 cells were induced to mature with retinoic acid (10(-6) mol/L), dimethylformamide (6 X 10(-2) mol/L), or a known IMPD inhibitor, tiazofurin (10(-6) mol/L), IMPD activity in the cells fell by 51% to 80% within three to six hours. These changes in IMPD activity preceded detectable functional and antigenic maturation of the cells by at least 12 hours and were not temporally related to changes in cellular proliferation. These findings are consistent with the concept that the regulation of myeloid cell maturation may be influenced by intracellular concentrations of guanine ribonucleotides because IMP dehydrogenase activity is known to be rate limiting for the production of these nucleotides.     

Transverse esophageal folds: association with corrosive injury

Two cases are presented in which transverse esophageal folds were observed in children following ingestion of corrosive material. Strictures developed at the sites that initially manifested this serrated mucosal appearance. These findings lend additional credence to the concept that transverse folds, reflecting contractions of the muscularis mucosae, represent a pattern of pathologic motility rather than merely a variant of normal mucosal anatomy.     

tdic(9;12): a nonrandom chromosome abnormality in childhood B-cell precursor acute lymphoblastic leukemia: a Pediatric Oncology Group Study

In a review of 432 children with newly diagnosed acute lymphoblastic leukemia (ALL), we identified a new nonrandom translocation, tdic(9;12)(p1?1;p1?2), in the leukemic marrow cells of eight patients. Seven had hypodiploid karyotypes that lacked chromosomes 9 and 12 and contained a der(12), tdic(9;12); the eighth had a pseudodiploid karyotype with two normal 9 chromosomes, one normal 12 and the der(12), tdic(9;12). Abnormalities involving chromosomes other than 9 and 12 were noted in four of the eight patients. All cells with the tdic(9;12) expressed both the common ALL antigen and HLA-DR. Cytoplasmic immunoglobulin, a marker of pre-B ALL, was detected in one case with the tdic(9;12) but was absent in the other seven. Our results suggest that the tdic(9;12)(p1?1;p1?2) rearrangement is specifically associated with leukemic B cell precursors.