While renal anemia can be successfully treated by use of erythropoietin (EPO) in most hemodialysis (HD) patients, some patients have anemia that is refractory to treatment with a high dose of EPO. We examined whether L-carnitine treatment could raise hematocrit (Hct) levels in such patients. Fourteen HD patients who showed a poor response to EPO and no evident factors which inhibit a response to EPO were selected to receive oral L-carnitine (500 mg/day) in a 3-month trial. During the study, 36% of the patients showed Hct increases of more than 2%. Statistical analysis revealed significant increases of Hct (p = 0.003) and total iron-binding capacity (TIBC) (p = 0.050) and a significant decrease of ferritin (p = 0.005). In addition, we found that red blood cells (RBCs) in HD patients contained a comparable level of carnitine to normal controls, despite the presence of serum carnitine deficiency, and that RBC carnitine was not removed through HD, in contrast to serum carnitine. These results suggest that RBC carnitine may be essential for RBCs to perform their metabolic function in renal anemia and that oral L-carnitine treatment could improve anemia in poor responders to EPO.

A newly established human lymphoma cell line (OZ) has the t(14;18)(q32;q21) translocation and expresses large amounts of Bcl-2 compared to CCRF-CEM cells. VP-16 (40 micrograms/mL), a promising agent against lymphoma, caused DNA fragmentation (26.9% of total DNA) typical for apoptosis at 6 h in CCRF-CEM cells, but no significant changes in OZ cells until 24 h after the addition of VP-16. However, coincubation with calphostin C (0.2 microgram/mL), a protein kinase C (PKC) inhibitor, induced DNA fragmentation in VP-16-treated OZ cells (13.5% of total DNA) at 6 h after the treatment. Simultaneous immunoblot analysis revealed that this induction of apoptosis coincided with the downregulation of serine-phosphorylated Bcl-2 (13% of control cells). By contrast, apoptosis induced by VP-16 in CCRF-CEM cells was attenuated by the addition of 0.5 microM phorbol 12-myristate 13-acetate, a potent PKC stimulator. These observations suggest that Bcl-2 function is partly regulated by phosphorylation/ dephosphorylation mechanisms of the PKC system, and that phosphorylated Bcl-2 in lymphoma cells may play a role in the prevention of apoptosis.

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