A 9-month-old infant with acquired idiopathic thrombotic thrombocytopenic purpura caused by inhibitory IgG-autoantibody to ADAMTS13.

Although acquired idiopathic thrombotic thrombocytopenic purpura (ai-TTP) is rare in children, the authors present the case of a 9-month-old boy with ai-TTP showing severe deficiency of ADAMTS13 activity by its inhibitory IgG-autoantibody (4.8 Bethesda units/mL). Plasma exchange therapy was clinically effective but transient.

Refractory chronic immune thrombocytopenic purpura in a child with acute lymphoblastic leukemia.

Immune thrombocytopenic purpura (ITP) has been associated with several hematologic malignancies such as Hodgkin and non-Hodgkin lymphomas and chronic lymphocytic leukemia, but it is rare in children with acute lymphoblastic leukemia (ALL). Here, we report a 7-year-old girl with chronic ITP during early intensive phase of chemotherapy for ALL. She underwent splenectomy because thrombocytopenia had persisted even after treatment with intravenous immunoglobulin (IVIG), steroids, vincristine, rituximab, and anti-D antibody.

Effect of aminoguanidine on lipopolysaccharide-induced changes in rat liver transporters and transcription factors.

To determine the role of nitric oxide (NO) in rat liver transporter regulation, we investigated whether NO mediates lipopolysaccharide (LPS)-induced changes in transporters and their transcription factor expression using aminoguanidine (AG), an inhibitor of induced nitric oxide synthase (iNOS). We confirmed that LPS decreased mRNA levels for Ntcp, Oatp1, Oatp2, Oatp4, Oct1, Mrp2, Mdr1a and increased those for Mdr1b at 16 h after administration. AG attenuated these decreases for Ntcp, Oatp1 and Oatp4 (retinoid X receptor (RXR)alpha- and hepatocyte nuclear factor (HNF)4alpha-dependent genes) and increase for Mdr1b (nuclear factor (NF)-kappaB-dependent gene).

Alteration in the cellular response to retinoic acid of a human acute promyelocytic leukemia cell line, UF-1, carrying a patient-derived mutant PML-RARalpha chimeric gene.

Cellular response to all-trans retinoic acid (ATRA) of acute promyelocytic leukemia (APL) with patient-derived mutant PML-retinoic acid receptor-alpha (PML-RARalpha) was investigated using an APL cell line, UF-1, carrying Arg611Trp mutation in PML-RARalpha. Although the mutant protein showed a decreased ligand-dependent transcriptional activity and retained a dominant-negative effect on normal RARalpha, UF-1 cells underwent growth inhibition, maturation and apoptosis in response to ATRA at 1 microM, but not < or = 100 nM, after 4 days of treatment with ATRA. Moreover, in the presence of 1 microM ATRA, approximately 50% of UF-1 cells expressing annexin V, an early-apoptotic marker, was negative for CD11b and showed immature morphology.

Acute renal failure due to leukemic cell infiltration followed by relapse at multiple extramedullary sites in a child with acute lymphoblastic leukemia.

Acute renal failure due to leukemic infiltration into the kidney is rare in childhood acute lymphoblastic leukemia (ALL). We report here a five year-old boy with ALL who presented acute renal failure caused by leukemic infiltration at onset. Treatment with predonisolone and hemodialysis was effective.