Efficacy of imatinib mesylate-based front-line therapy in pediatric chronic myelogenous leukemia

PurposeDespite the established role of imatinib (IM) in chronic myelogenous leukemia (CML) in adults, there are few reports on its efficacy in children. In this study, we compared the outcomes of children with CML before and after the advent of IM-based treatment.MethodsThe study cohort consisted of 52 patients treated for CML at the Department of Pediatrics, The Catholic University of Korea from January 1995 to October 2010. Patients were divided and analyzed according to the preImatinib group (pre-IMG) and imatinib group (IMG).ResultsMedian age at diagnosis for the overall cohort (pre-IMG, n=27; IMG, n=25) was 9 years, with a median follow-up duration of survivors of 84 months. Except for 5 patients in the IMG, all were diagnosed in chronic phase (CP). The overall survival (OS) of patients diagnosed in CP was 45.7% and 89.7% for pre-IMG and IMG, respectively (P=0.025). The OS of hematopoietic stem cell transplantation (HSCT) recipients in the 2 groups was similar, but the OS of patients diagnosed in CP who did not receive HSCT was superior in IMG (91.7% vs. 16.7%, P=0.014). Of the 12 patients in IMG who remained on IM without HSCT, 2 showed disease progression, compared to 11 of 12 in pre-IMG. No difference was observed in the progression free survival (PFS) of matched donor HSCT recipients and IM-based treatment recipients.ConclusionSimilar PFS of patients treated with IM and those who received matched donor HSCT underscore the potential of IM as effective first-line treatment in childhood CML

Efficacy of Tandem High-Dose Chemotherapy and Autologous Stem Cell Rescue in Patients Over 1 Year of Age with Stage 4 Neuroblastoma: The Korean Society of Pediatric Hematology-Oncology Experience Over 6 Years (2000-2005)

The efficacy of tandem high-dose chemotherapy and autologous stem cell rescue (HDCT/ASCR) was investigated in patients with high-risk neuroblastoma. Patients over 1 yr of age who were newly diagnosed with stage 4 neuroblastoma from January 2000 to December 2005 were enrolled in The Korean Society of Pediatric Hematology-Oncology registry. All patients who were assigned to receive HDCT/ASCR at diagnosis were retrospectively analyzed to investigate the efficacy of single or tandem HDCT/ASCR. Seventy and 71 patients were assigned to receive single or tandem HDCT/ASCR at diagnosis. Fifty-seven and 59 patients in the single or tandem HDCT group underwent single or tandem HDCT/ASCR as scheduled. Twenty-four and 38 patients in the single or tandem HDCT group remained event free with a median follow-up of 56 (24-88) months. When the survival rate was analyzed according to intent-to-treat at diagnosis, the probability of the 5-yr event-free survival±95% confidence intervals was higher in the tandem HDCT group than in the single HDCT group (51.2±12.4% vs. 31.3±11.5%, P=0.030). The results of the present study demonstrate that the tandem HDCT/ASCR strategy is significantly better than the single HDCT/ASCR strategy for improved survival in the treatment of high-risk neuroblastoma patients

Development of microstructure in mechanically alloyed NiAl

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Microstructural Evolution in Twin-Roll Strip Cast Mg Alloys

Mg-6wt.% Zn-1wt.% Mn-1wt.% Al (ZMA611) alloy was strip cast into 2 nun thick strip. Microstructure of the as-cast ZMA611 alloy strip shows equiaxed alpha-Mg dendritic structure across the thickness of the strip. Continuous metastable phase and primary Al8Mn5 particle are formed in the interdendritic region. It has been found that, in T4 condition, interdendritic phases are disappeared within alpha-Mg except thermally stable primary Al8Mn5 particles. In addition, fine secondary Al8Mn5 dispersoids precipitate from supersaturated as-strip cast alpha-Mg after solution treatment. These dispersoid particles retard the motion of dislocations to increase strength and at the same time the blocked dislocations change the slip systems by cross-slip to maintain good ductility.open0

Effect of nano-particles on the creep resistance of Mg-Sn based alloys

A study has been made on the microstructure and high-temperature properties of die-cast Mg-Sn-Al-Si (TAS831) alloy. Microstructure of TAS831 alloy is characterized by the presence of thermally stable Mg2Sn nano-particles within the matrix. It also contains Mg2Sn and Mg2Si particles along grain boundaries. It has been shown that the morphology of matrix Mg2Sn particles varies depending on cooling rate, forming rod-type Mg2Sn particles at fast cooling rates and polygonal particles at slow cooling rates. Elevated-temperature creep tests show that the die-cast TAS831 alloy has superior creep resistance compared with commercial AZ91 alloy. Analyses of creep and load relaxation at elevated temperatures in the context of internal-variable theory indicate that the presence of thermally stable nano-particles within the matrix increases the resistance to dislocation movement, thereby improving the creep resistance.close524

Effect of Alloying Elements on the Microstructural Evolution of Mg-Sn Based Cast Alloys

A study has been made on the effect of Sb and Sr on the microstructure and mechanical properties of Mg-Sn-Al-Si based (TAS) alloy. When Sb is added more than 3 wt.%, Mg3Sb2 particles acted as nucleation sites for Mg2Si and Mg2Sn particles. Increased volume fraction and decreased shape factor of the particles improved the hardness of the alloys. When Sr is added, a few kinds of particles such as rod-like MgSi2Sr, SiSr2 and polygonal Sr5Sn3 particles are formed within the microstructure. Large volume fraction and uniform distribution of the particles greatly improved the hardness of the alloys. These microstructural changes by Sb, Sr addition are also expected to have beneficial effect on the room and high temperature mechanical properties