Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Children with Down's syndrome suffer many diseases among which cardiovascular diseases, increased susceptibility to infections, leukemia, endocrine alterations, immune defects, nutritional disturbance and mental retardation have clinical relevance. It has been suggested that the pathogenesis of Down's syndrome involves reactive oxygen species arising from a mutation in gene encoding, which disproportionately elevates superoxide dismutase activity. Reactive oxygen species and total antioxidant capacity were evaluated using two new spectrophotometric methods in a selected group of 40 children with Down's syndrome and in 20 apparently healthy children used as controls. Reactive oxygen species were significantly higher (p <0.05) in children with Down's syndrome than in controls: 452 (+/- 72) U.Carr vs. 270 (+/- 66) U.Carr respectively. Total antioxidant capacity was significantly higher (p <0.05) in controls than in children with Down's syndrome: 380 (+/- 52) micromol hypochlorous acid (HCLO)/ml vs. 281 (+/- 33) micromol HCLO/ml, respectively. In fact, thiol groups (sulfhydryl) were significantly higher (p <0.05) in controls than in children with Down's syndrome: 644 (+/- 78) micromol/l vs. 462 (+/- 54) micromol/l, respectively Our data show how to simply measure chemical indices of oxidative status in serum samples from children with Down's syndrome. We determined the plasmatic activities of reactive oxygen metabolites and oxidative defense molecules. Accumulated macromolecular damage may be one of the causes of some of the abnormalities that are considered part of the syndrome. Therefore, children with Down's syndrome have to cope with a significant prooxidant environment. Oxidative stress causes alterations such as atherosclerosis, early aging, immunological default and neurologic disorders in Down's syndrome patients. The new test available for measuring reactive oxygen species in serum proved to be reliable and useful as an early marker of tissue damage.
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PMID:Reactive oxygen metabolites and prooxidant status in children with Down's syndrome. 1182 51

Methylphenidate is the psychotropic drug most commonly used to treat individuals suffering from developmental attention-deficit-hyperactivity disorder. Additional attention deficit is part of numerous neurologic diseases in childhood. Despite the vast extent of scientific research on methylphenidate, the use of this stimulant in the treatment of cognitive and behavioral dysfunction in children with epilepsy, brain tumor, leukemia, closed brain injury, encephalitis, meningitis, or mental retardation continues to be controversial. Only few data exist about the efficacy and side effects of methylphenidate treatment in children with this neurologic illness or history. The aim of the present study is to provide a review of this important clinical topic and perhaps to stimulate further controlled investigations.
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PMID:Methylphenidate treatment. 1199 52

Down syndrome (DS) is a frequent chromosomal aberration. Triplication of the fragment 21q22 of chromosome 21 is sufficient to cause the DS phenotype including immunodeficiency, premature aging, mental retardation, and an increased risk of leukemia. Chromosomal aberrations caused by X-ray irradiation were observed in DS lymphocytes and DS fibroblasts, but the correlation between chromosomal sensitivity, repair deficiency, and radioresistant DNA synthesis was not clear. Here some insight into the nature of this problem has been made. Besides, new arguments have been provided in favour of genetic heterogeneity of this genetic disorder.
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PMID:[Down syndrome: pathogenesis, radioresistant DNA synthesis and chromosomal instability]. 1214 83

One of the most relevant concerns in long-term survivors of paediatric acute lymphoblastic leukaemia (ALL) is the development of neuropsychological sequelae. The majority of the published studies report on patients treated with chemotherapy and prophylactic central nervous system (CNS) irradiation, little is known about the outcome of patients treated with chemotherapy-only regimens. Using the standardised clinical and neuropsychological instruments of the SPOG Late Effects Study, the intellectual performance of 132 paediatric ALL patients treated with chemotherapy only was compared to that of 100 control patients surviving from diverse non-CNS solid tumours. As a group, ALL and solid tumour survivors showed normal and comparable intellectual performances (mean global IQ 104.6 in both groups). The percentage of patients in the borderline range (global IQ between 70 and 85) was comparable and not higher as expected (10% cases and 13% controls, expected 16%). Only 2 (2%) of the former ALL and 1 (1%) of the solid tumour patients were in the range of mental retardation (global IQ<70). Former known risk factors described in children treated with prophylactic CNS irradiation, like a younger age at diagnosis of ALL and female gender, remained valid in chemotherapy-only treated patients. The abandonment of prophylactic CNS irradiation and its replacement by a more intensive systemic and intrathecal chemotherapy led to a reduction, but not the disappearance of late neuropsychological sequelae.
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PMID:Intellectual outcome in children and adolescents with acute lymphoblastic leukaemia treated with chemotherapy alone: age- and sex-related differences. 1256 89

Wolf-Hirschhorn syndrome (WHS) is a rare chromosomal disorder attributable to a deletion at the short arm of chromosome 4. This syndrome is associated with characteristic facial appearance, multiple congenital abnormalities, mental retardation, feeding difficulties and failure to thrive. We report two girls with WHS who developed myelodysplastic syndrome (MDS). According to the "Category, Cytology, Cytogenetic (CCC)"classification of childhood MDS, patient 1 had refractory cytopenia with ring sideroblasts at the age of 6 years, while patient 2 had refractory cytopenia with dysplasia at the age of 5-1/2 years. Patient 1 progressed to refractory cytopenia with excess blasts within a year, while patient 2 progressed to acute lymphoblastic leukemia within 1 month of presentation. It is possible that allelic loss of a tumor suppressor gene such as WHSC1 and/or FGFR3 from the deleted segment 4p16.3 plays a critical role in the process of malignant transformation. To our knowledge, this is the first report of severe hematological complications like MDS and leukemia in children with WHS and may be an important genetic model for understanding malignant hematological transformation. This report also underscores the importance of evaluating children with WHS for hematopoietic dysfunction.
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PMID:Malignant hematological disorders in children with Wolf-Hirschhorn syndrome. 1274 63

The haemopoietic system in the developing mammal is very sensitive to the damaging effects of ionizing radiation. Epidemiological studies have established a strong association between obstetric exposure to diagnostic radiation and an increase in the incidence of childhood leukaemia and between low dose gamma irradiation during the early fetal period and mental retardation in children. It has been suggested that insufficient oxygen supply to the developing brain due to radiation induced damage to fetal haemopoietic tissue has a role in inducing the severe mental retardation observed in the Japanese children exposed to atom bomb radiation in utero. Experimental studies have shown that X- and gamma irradiation of pregnant mice with <1 Gy during the late organogenesis or fetal period caused chromosome damage and significant depletion in the fetal haemopoietic progenitor cells and led to haematological disorders in the adults. The present paper reviews the experimental findings on the effect of pre-natal irradiation on the fetal haemopoietic system and its long-term consequences.
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PMID:Radiosensitivity of the developing haemopoietic system in mammals and its adult consequences: animal studies. 1281 21

Nijmegen breakage syndrome (NBS) is characterized by growth retardation, microcephaly, mental retardation, immunodeficiency, and predisposition to malignancies, especially B-cell lymphomas. In contrast, leukemia is rare. A 23-year-old NBS patient presented with anemia, thrombocytopenia, and hyperlymphocytosis. The diagnosis of T-cell prolymphocytic leukemia (T-PLL) was confirmed by cytological and immunological assays (TdT(-), CD2(+), CD5(+), CD3m, and CD7(+)). Biological assays also showed a hemolytic anemia and a clotting factor V decrease. The patient was first treated by methylprednisone for 3 weeks. During this period the lymphocyte count decreased. The simultaneous normalization of the hemolysis and of factor V suggested that both could be related to T-PLL. Since T-PLL is refractory to conventional therapies with a poor prognosis, an intensive chemotherapy such as 2'-deoxycoformycin with anti-CDw52 monoclonal antibodies is usually favored. In the present case, however, because of the specific context (i.e., NBS-induced immunodepression, severe hemolytic anemia, and acquired factor V deficiency), he received pentostatin weekly during 1 month and in maintenance during 6 months. At last follow-up (7 months) he showed a persistent control of the lymphocytosis with no side effect.
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PMID:T-cell prolymphocytic leukemia with autoimmune manifestations in Nijmegen breakage syndrome. 1284 81

Down syndrome is the most common birth defect associated with mental retardation. Identifying proteins that are aberrantly expressed therefore helps to understand how chromosomal imbalance leads to subnormal intelligence in Down syndrome. In the present study, we generated a fetal brain map with the use of an analytical method based on two-dimensional electrophoresis coupled with mass spectrometry and searched the proteome for differential protein expression. Among 49 proteins analyzed in seven control and nine Down syndrome fetuses, we found 11 proteins that have been deregulated in cerebral cortex of fetal Down syndrome. While double-strand break repair protein rad 21 homologue, eukaryotic translation initiation factor 3 subunit 5, mixed lineage leukemia septin-like fusion protein-B and heat shock protein 75 were increased; beta-amyloid precursor-like protein 1, tropomyosin 4-anaplastic lymphoma kinase fusion oncoprotein type 2, Nck adaptor protein 2, Src homology domain growth factor receptor bound 2-like endophilin B2, beta tubulin, septin 7 and hematopoietic stem/progenitor cells 140 were decreased. The current data suggest that misexpression of proteins that have functions ranging from signaling to cellular structural organization could contribute to or reflect brain dysgenesis in Down syndrome.
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PMID:Aberrant protein expression in cerebral cortex of fetus with Down syndrome. 1459 56

A 27-year-old woman had congenital lissencephaly syndrome and mental retardation. She had a fever of unknown origin and visited her local physician. Blood test indicated leukocytosis, so she was referred to our hospital for detailed examination. She was diagnosed to have acute myelogeneous leukemia (M5a). The chromosome analysis in blast cells revealed Robertsonian 13;21 translocation. Complete remission was obtained by induction chemotherapy. As normal karyotype (46, XX) was observed in the chromosome analysis of bone marrow cells after remission, it was considered that the patient had acquired Robertsonian 13;21 translocation complicated by acute myelogeneous leukemia.
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PMID:Acute myelogeneous leukemia (M5a) that demonstrated chromosomal abnormality of robertsonian 13;21 translocation at onset. 1528 89

We have established that the gene AF4, which had long been recognized as disrupted in childhood leukemia, also plays a role in the CNS. Af4 is mutated in the robotic mouse that is characterized by ataxia and Purkinje cell loss. To determine the molecular basis of this mutation, we carried out a yeast two-hybrid screen and show that Af4 binds the E3 ubiquitin ligases Drosophila seven in absentia (sina) homologues (Siah)-1a and Siah-2 in the brain. Siah-1a and Af4 are expressed in Purkinje cells and colocalize in the nucleus of human embryonic kidney 293T and P19 cells. In vitro binding assays and coimmunoprecipitation reveal a significant reduction in affinity between Siah-1a and robotic mutant Af4 compared with wild-type, which correlates with the almost complete abolition of mutant Af4 degradation by Siah-1a. These data strongly suggest that an accumulation of mutant Af4 occurs in the robotic mouse due to a reduction in its normal turnover by the proteasome. A significant increase in the transcriptional activity of mutant Af4 relative to wild-type was obtained in mammalian cells, suggesting that the activity of Af4 is controlled through Siah-mediated degradation. Another member of the Af4 family, Fmr2, which is involved in mental handicap in humans, binds Siah proteins in a similar manner. These results provide evidence that a common regulatory mechanism exists that controls levels of the Af4/Fmr2 protein family. The robotic mouse thus provides a unique opportunity to understand how these proteins play a role in disorders as diverse as leukemia, mental retardation, and neurodegenerative disease.
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PMID:Mediation of Af4 protein function in the cerebellum by Siah proteins. 1545 19


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