IgA1(kappa)-transferrin complex was ascertained in a case of multiple myeloma with hypersiderinemia. On gel filtration, this complex disclosed an orange-colored protein with two peaks between the 19S and 7S fractions. On polyacrylamide gel electrophoresis and Western blotting analysis, the complex migrated at molecular weights of 430 and 700 kD in the non-reducing condition. A small amount of free transferrin was detected simultaneously. The complex was further separated into monoclonal IgA1(kappa) and transferrin at pH 4.5; these recombined at pH 7.2 after incubation (37 degrees C, 2 h). We also showed that the pepsin-digested F(ab')2 fragment of IgA1(kappa) combined with the transferrin. From these results it can be suggested that monoclonal IgA1(kappa) has an antibody activity for the transferrin. Clinically, this complex distributed the iron transport to erythroid cells in the bone marrow, resulting in hypersiderinemia, anemia, and iron deposits in the liver.

Aged↗

PubMedDate not supplied

Role of sodium pump systems to determine sensitivity to mitomycin C in non-small cell lung cancer cell lines.

There are some active transport systems in the cell membrane, such as potassium pump, calcium pump, and proton pump. Although it has been reported that sodium/potassium and sodium/calcium pumps of cell membrane play roles in the intracellular accumulation of anticancer agents, the significance of the active transport channels in accumulation of mitomycin C (MMC), one of the most active agents for non-small cell lung cancer (NSCLC) has been unclear. In this study, we evaluated the role of the potassium pump, calcium pump, and proton pump as determinants of the sensitivity to MMC in vitro by using the selective inhibitors, ouabain, verapamil or AG-2000 (an active metabolite of Lansoplazole), respectively. PC-9 and PC-9/MC4 cell lines which are sensitive and resistant to MMC were used for these experiments. PC-9/MC4 was 9.4-fold more resistant to MMC than PC-9 cells. Relative resistance was not significantly changed by co-incubation with a non-cytotoxic dosage of these inhibitors. From these results, it was revealed that the active transport systems in cell membrane do not play a role in determining the sensitivity to MMC and the acquisition of resistance to MMC in PC-9 cell lines. Intracellular bioactivation may be an important factor to determine sensitivity to MMC in NSCLC cells under aerobic conditions.

Antineoplastic Agents↗