Retinoic acid-induced differentiation in a human neuroblastoma cell line is associated with an increase in nitric oxide synthesis.

The human neuroblastoma cell line SK-N-BE, after incubation with 10 microM retinoic acid (RA) or 20 nM phorbol 12-myristate 13-acetate (PMA), underwent biochemical and morphological signs of differentiation within 10-14 days. In parallel, SK-N-BE cells produced significantly higher amounts of nitric oxide (NO) in comparison with controls, as assessed by the measurement of nitrite and nitrate in the culture supernatant and of NO synthase (NOS) activity in the cell lysates (measured as ability to convert [3H]arginine into [3H]citrulline and as NADPH diaphorase activity). Nitrite/nitrate production was abolished by adding the NO scavenger hemoglobin in the culture medium and was inhibited by aminoguanidine (AG, a selective inhibitor of the inducible NOS isoform) but not by the less selective inhibitor NG-nitro-L-arginine methylester (NAME).

Correlation between nitric oxide synthase activity and reduced glutathione level in human and murine endothelial cells.

The synthesis of nitric oxide (NO), detected as citrulline production, in human (HUVEC) and murine (tEnd.1) endothelial cells correlated with intracellular GSH. tEnd.

Serum erythropoietin level and marrow erythroid infiltration predict response to recombinant human erythropoietin in myelodysplastic syndromes.

Background And Methods: In 38 patients with myelodysplastic syndromes (MDS) the values of serum erythropoietin were measured at diagnosis and compared with the haemoglobin level. A highly significant inverse relationship was found between these two parameters, suggesting that the physiologic mechanism of erythroid progenitor cell recruitment is preserved in MDS. Fourteen transfusion-dependent patients were treated with recombinant human erythropoietin at the dose of 150 U/Kg three times weekly for at least 2 months.

Evaluation of bone marrow cellularity by magnetic resonance imaging in patients with myelodysplastic syndrome.

Magnetic resonance imaging (MRI) is a safe modality for examining the bone marrow and it is quite effective in revealing marrow involvement in hematological malignancies. MRI has been compared with needle marrow biopsy in 22 patients with myelodysplastic disorders. A fairly good concordance has been demonstrated in 79% of cases.