ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Sickle cell anemia is characterized by the presence of dense dehydrated erythrocytes that have lost most of their K content. Due to the unique dependence of Hb S polymerization on intracellular Hb S concentration, preventing this dehydration should markedly reduce polymerization. The erythrocyte intermediate conductance Ca-activated K channel (hSK4 or KCNN4), first described by Gardos, has been shown to be a major pathway for sickle cell dehydration. Studies with the imidazole antimycotic clotrimazole have shown reduction of sickle cell dehydration in vivo in a small number of patients with sickle cell disease; dose-limiting gastrointestinal and liver toxicities were observed. Based on the chemical structure of clotrimazole metabolites, a novel Gardos channel inhibitor, ICA-17043, has been developed. It has shown substantial activity both in vitro and in vivo in transgenic sickle mice. ICA-17043 is currently in phase 2 human trials. Another potential therapeutic target is the K-Cl cotransport. When sickle erythrocytes are exposed to relatively acidic conditions, they undergo cell shrinkage via activation of this pathway. K-Cl cotransport can be blocked by increasing the abnormally low erythrocyte Mg content of sickle erythrocytes. Oral Mg supplementation has been shown to reduce sickle cell dehydration in vivo in transgenic sickle mice and in patients in two separate clinical trials. Oral Mg pidolate is being tested in clinical trials in homozygous sickle cell disease and in Hb S/HbC (SC) disease, either as a single agent or in combination with hydroxyurea. The ongoing trials will determine the clinical effectiveness of therapies aimed at preventing sickle erythrocyte dehydration.

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectiveTo assess the efficacy and toxicity of local radiotherapy in achieving local control in patients with stage 4 or high-risk stage 3 neuroblastoma treated with induction chemotherapy and tandem stem cell transplants.MethodsFifty-two children with stage 4 or high-risk stage 3 neuroblastoma were treated on a standardized protocol that included five cycles of induction chemotherapy, surgical resection of the primary tumor when feasible, local radiotherapy, and then consolidation with tandem myeloablative cycles with autologous peripheral blood stem cell rescue. Local radiotherapy (10.5–18 Gy) was administered to patients with gross or microscopic residual disease prior to the myeloablative cycles. Thirty-seven patients received local radiotherapy to the primary tumor or primary tumor bed. Two patients with unknown primaries each received radiotherapy to single, unresectable, bulky metastatic sites. The second of the myeloablative regimens included 12 Gy of total body irradiation.ResultsOf the 52 consecutively treated patients analyzed, 44 underwent both transplants, 6 underwent a single transplant, and 2 progressed during induction. Local radiotherapy did not prolong recovery of hematopoiesis following transplants, did not increase peritransplant morbidity, and did not prolong the hospital stay compared with patients who had not received local radiotherapy. Local control was excellent. Of 11 patients with disease recurrence after completion of therapy, 9 failed in bony metastatic sites 3 to 21 months after the completion of therapy, 1 recurred 67 months following therapy in the previously bulky metastatic site that had been irradiated, and 1 had local recurrence concurrent with distant progression 15 months following the second transplant. The three-year event-free survival was 63%, with a median follow-up of 29.5 months. The actuarial probability of local control was 97%.ConclusionsThe use of induction chemotherapy, aggressive multimodality therapy for the primary tumor, followed by tandem myeloablative cycles with stem cell transplant in patients with stage 4 or high risk stage 3 neuroblastoma has resulted in acceptable toxicity, a very low local recurrence risk, and an improvement in survival.

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectivesTo determine the activity of the DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) andMGMTpromoter methylation status of pediatric rhabdomyosarcoma (RMS) and examine MGMT in RMS tumors from different prognostic groups.MethodsFifteen samples each of the alveolar (ARMS) and embryonal (ERMS) subtypes were obtained for analysis of MGMT activity and promoter methylation status. MGMT activity was assayed by measuring the removal of O6-[3H] methylguanine from [3H]-methylated substrate by a tumor extract containing the enzyme. Promoter methylation status was examined using methylation-specific polymerase chain reaction (PCR).ResultsMGMT activity was successfully assayed from 25 samples, 10 ERMS and 15 ARMS. All ERMS and 11 of the 15 ARMS samples displayed high activity levels. There was significant intertumor variability among both subtypes but no significant difference in mean activity between the two histologic groups. There were trends toward increased activity in ERMS tumors and tumors from anatomically unfavorable locations. Only one tumor was hypermethylated at theMGMTpromoter region.ConclusionsThis analysis suggests that a low percentage of RMS samples are hypermethylated at theMGMTpromoter and that most have significant MGMT activity, implying that clinical trials with MGMT-modulating agents may have a role in the treatment of these tumors. This analysis does not support MGMT activity as an explanation of the differential response to chemotherapy demonstrated by ARMS and ERMS, but does suggest that MGMT may be involved in RMS treatment failure regardless of subtype and in the poorer response shown by tumors from unfavorable locations.

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectivePearson bone marrow-pancreas syndrome (PS) is a rare, usually fatal mitochondrial disorder involving the hematopoietic system in early infancy. Due to the diversity of clinical symptoms, the diagnosis can be difficult. The authors describe a boy with severe hypoplastic anemia in whom extensive clinical, biochemical, and morphologic findings led to the diagnosis of PS, and molecular analysis revealed a novel deletion of mitochondrial DNA from nucleotide position 10.371 to 14.607.MethodsThe patient is a 2-year-old boy who presented at age 5 months with hypoplastic macrocytic anemia. His first months of life and the family history were uneventful. Extensive pretransfusion evaluations did not reveal a metabolic, infectious, or hematologic-neoplastic etiology, and he had no evidence of exocrine pancreatic insufficiency. However, a second bone marrow aspirate at age 7 months showed a reduced cell number, vacuolated erythroblasts and myeloblasts, and ringed sideroblasts, so PS was suspected.ResultsAdditional molecular analysis from the boy's blood leukocytes revealed a deletion of mitochondrial DNA from nucleotide position 10.371 to 14.607, which was absent in his mother's blood cells, consistent with a sporadic mutation as commonly seen in PS. The muscle histology and the respiratory chain enzymes were normal.ConclusionsMitochondriopathies should be considered in children with persistent non-neuromuscular symptoms such as unexplained refractory anemia. Due to the often-fatal course of PS, the rapid detection of mitochondrial DNA deletions is imperative for diagnosis and family counseling.

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectivesRetrospective cholecystography studies in adults with hereditary spherocytosis (HS) suggested detectable gallstones in 37% to 43% of patients. Since longitudinal studies using biliary ultrasonography are unavailable, the aim of the present study was to determine the incidence of gallstone disease, as detected by biliary ultrasonography, in children and young adults with HS. As individuals with HS who co-inherit Gilbert syndrome have a greater risk of developing gallstones, uridine diphosphate-glucuronyl transferase (UGT-1A) gene polymorphism was also determined.Patients and MethodsThe authors retrospectively evaluated 44 patients aged 1.4 to 22 years with HS, 12 (27%) of whom underwent splenectomy. Ultrasonography was performed annually starting at the age of 4 years or at the time of diagnosis, if later.ResultsOf the 44 patients, 18 (41%) developed cholelithiasis as demonstrated by gallbladder ultrasonography. In most patients (94%) the test first proved positive at age 4 to 13 years. Patients with HS and Gilbert syndrome tended to be younger at the time of cholelithiasis.ConclusionsEarly cholelithiasis was detected in children and young adults with HS. To identify this complication, the authors recommend early annual biliary ultrasonography in HS children, starting at about 4 years of age. In patients with Gilbert syndrome, closer follow-up may be indicated.

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

PurposeTo determine the incidence, etiology and outcome of graft failure in pediatric allogeneic bone marrow transplant (BMT) recipients.Patients and MethodsPatients with primary or secondary graft failure were identified by database review. A retrospective chart review was performed. Etiologic factors were identified and assessed for statistical significance.Results309 children underwent allogeneic BMT during the time interval studied. Four cases of primary graft failure and 7 cases of secondary graft failure occurred. Nonmalignant diagnosis, lower total nucleated cell (TNC) dose, and conditioning without total body irradiation were associated with a higher incidence of graft failure. Donor source, donor/recipient CMV status, CD34+ cell dose, and alloimmunization were not associated with graft failure.ConclusionsGraft failure is a relatively uncommon occurrence in pediatric patients. Autologous reinfusion may allow time to prepare the patient for a second transplant and decrease complications associated with aplasia. More immunosuppressive conditioning regimens may decrease the incidence of graft failure, particularly in patients with non-malignant diseases or those with lower stem cell doses. More frequent monitoring of chimerism by VNTR analysis may detect late graft failure earlier and allow for more rapid intervention.

ISSN:1077-4114    

出版商:OVID    

年代:2003

数据来源: OVID