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Ma SK, Wan TS, Cheuk AT, Fung LF, Chan GC, Chan SY, Ha SY, Chan LC. Characterization of additional genetic events in childhood acute lymphoblastic leukemia with TEL/AML1 gene fusion: a molecular cytogenetics study. Leukemia 2001; 15:1442-7. [PMID: 11516105 DOI: 10.1038/sj.leu.2402202] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2000] [Accepted: 05/02/2001] [Indexed: 11/09/2022]
Abstract
TEL/AML1 gene fusion that results from a cryptic t(12;21) is the most common genetic aberration in childhood B-lineage acute lymphoblastic leukemia (ALL). While the translocation may initiate the leukemic process, critical secondary genetic events are currently believed to be pivotal for leukemogenesis. We investigated 12 cases of childhood ALL with TEL/AML1 gene fusion by fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) and documented additional or secondary genetic changes in seven patients (58%). Three patients showed extra copies of chromosome 21 including a case in which the trisomy 21 (+21) clone was distinct from the one harboring TEL/AML1 gene fusion. Interestingly, one patient without +21 showed amplification of the AML1 gene on chromosome 21q, supporting the contention that AML1 amplification may be an important additional genetic event. Gene expression study by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) in two of these four patients showed an increase in AML1 transcripts that paralleled the increase in gene copy number. Deletion of the normal TEL allele was detected in two patients, with one of them showing loss of chromosome 12 together with duplication of the der(12)t(12;21). Finally, one patient showed duplication of the fusion signal. Our findings confirm that additional or secondary genetic changes including AML1 amplification are commonly encountered in childhood ALL with TEL/AML1 gene fusion, which are envisaged to play significant roles in disease progression.
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Chan GC, Leung YL, Shing MM, Luk CW, Ling SC, Lee AC. Does a "false negative" MIBG scan predict a better outcome in neuroblastoma patients? MEDICAL AND PEDIATRIC ONCOLOGY 2001; 37:155. [PMID: 11496360 DOI: 10.1002/mpo.1190] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Ma Z, Morris SW, Valentine V, Li M, Herbrick JA, Cui X, Bouman D, Li Y, Mehta PK, Nizetic D, Kaneko Y, Chan GC, Chan LC, Squire J, Scherer SW, Hitzler JK. Fusion of two novel genes, RBM15 and MKL1, in the t(1;22)(p13;q13) of acute megakaryoblastic leukemia. Nat Genet 2001; 28:220-1. [PMID: 11431691 DOI: 10.1038/90054] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
t(1;22) is the principal translocation of acute megakaryoblastic leukemias. Here we show this chromosomal rearrangement to result in the fusion of two novel genes, RNA-binding motif protein-15 (RBM15), an RNA recognition motif-encoding gene with homology to Drosophila spen, and Megakaryoblastic Leukemia-1 (MKL1), a gene encoding an SAP (SAF-A/B, Acinus and PIAS) DNA-binding domain.
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Zhou X, Ha SY, Chan GC, Luk CW, Chan V, Hawkins B, Lam YH, Liang RH, Lau YL. Successful mismatched sibling cord blood transplant in Hb Bart's disease. Bone Marrow Transplant 2001; 28:105-7. [PMID: 11498754 DOI: 10.1038/sj.bmt.1703104] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2001] [Accepted: 04/30/2001] [Indexed: 11/09/2022]
Abstract
A 20-month-old girl with Hb Bart's disease, who had survived neonatal complications, underwent HLA-DR antigen mismatched sibling cord blood transplantation successfully. Immune thrombocytopenia, which occurred around 2.5 months after transplant, responded to intravenous gamma-globulin. The fetal hemoglobin level rose to a peak of 52.3% on day +69 post transplant and declined gradually during the following year. Ten percent of hemoglobin Bart's was detected 2 months after transplant and this reflects the alpha-thalassemia trait of the donor.
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Ho HK, Ha SY, Lam CK, Chan GC, Lee TL, Chiang AK, Lau YL. Alloimmunization in Hong Kong southern Chinese transfusion-dependent thalassemia patients. Blood 2001; 97:3999-4000. [PMID: 11405212 DOI: 10.1182/blood.v97.12.3999] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Chan GC, Lernmark U, Xia Z, Storm DR. DNA elements of the type 1 adenylyl cyclase gene locus enhance reporter gene expression in neurons and pinealocytes. Eur J Neurosci 2001; 13:2054-66. [PMID: 11422446 DOI: 10.1046/j.0953-816x.2001.01578.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Ca2+-stimulated type 1 adenylyl cyclase (AC1) contributes to several forms of synaptic plasticity and is the only known neurospecific adenylyl cyclase. Furthermore, the protein and mRNA levels of AC1 undergo a circadian oscillation in the pineal gland, and AC1 may play a pivotal role in regulating nocturnal melatonin synthesis. To better understand the expression of AC1, we isolated mouse genomic DNA clones of AC1. The transcription and translation start regions of mouse AC1 share extensive homologies with the bovine counterpart. The upstream proximal region has potential binding sites for transcription factors, including the steroid receptor family, the E-box factors, and Sp1. A 280-bp fragment that contains the transcription start site directed reporter gene expression in cultured cortical neurons and pinealocytes functioning as a basal neuro- and pineal-directed promoter. Interestingly, pinealocyte expression of the reporter gene was inhibited by increases in cAMP. This cAMP sensitivity may explain why AC1 mRNA in the pineal is low at night when cAMP is elevated and high during the day when cAMP signals drop. An adjacent 330-bp fragment interacted specifically with nuclear factor(s) that we designate binary E-box factor (BEF). Methylation interference and DNase I footprinting identified the BEF-binding site sequence as 5'-CCAAGGTCACGTGGC-3'. When linked to the basal tissue-directed promoter, this 15-bp sequence further enhanced reporter expression in neurons and pinealocytes. We propose that this 15-bp sequence may contribute to increased expression of AC1 in neurons and pinealocytes relative to other cells.
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Chan GC, Ha SY, Lau YL, Chan KL, Tam PK, Cheung A. Linitis plastica presenting as malignant ascites. MEDICAL AND PEDIATRIC ONCOLOGY 2001; 36:408-9. [PMID: 11241451 DOI: 10.1002/mpo.1101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ma SK, Wan TS, Chan GC, Ha SY, Fung LF, Chan LC. Relationship between transient abnormal myelopoiesis and acute megakaryoblastic leukaemia in Down's syndrome. Br J Haematol 2001; 112:824-5. [PMID: 11260090 DOI: 10.1046/j.1365-2141.2001.02616.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Chiu SS, Chan GC, Loong F. Epstein-Barr virus (EBV) induced hemophagocytic syndrome followed by EBV associated T/NK lymphoma in a child with perinatal human immunodeficiency virus (HIV) infection. MEDICAL AND PEDIATRIC ONCOLOGY 2001; 36:326-8. [PMID: 11452946 DOI: 10.1002/1096-911x(20010201)36:2<326::aid-mpo1076>3.0.co;2-l] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Ma SK, Ha SY, Chan AY, Chan GC, Lau YL, Chan LC. Two novel beta-thalassemia alleles in the Chinese: the IVS-II-2 (-T) and nucleotide +8 (C-->T) beta-globin gene mutations. Hemoglobin 2000; 24:327-32. [PMID: 11186264 DOI: 10.3109/03630260008993141] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Chiang AK, Chan GC, Ma SK, Ng YK, Ha SY, Lau YL. Disseminated fungal infection associated with myeloperoxidase deficiency in a premature neonate. Pediatr Infect Dis J 2000; 19:1027-9. [PMID: 11055615 DOI: 10.1097/00006454-200010000-00024] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wong ST, Trinh K, Hacker B, Chan GC, Lowe G, Gaggar A, Xia Z, Gold GH, Storm DR. Disruption of the type III adenylyl cyclase gene leads to peripheral and behavioral anosmia in transgenic mice. Neuron 2000; 27:487-97. [PMID: 11055432 DOI: 10.1016/s0896-6273(00)00060-x] [Citation(s) in RCA: 319] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cyclic nucleotide-gated ion channels in olfactory sensory neurons (OSNs) are hypothesized to play a critical role in olfaction. However, it has not been demonstrated that the cAMP signaling is required for olfactory-based behavioral responses, and the contributions of specific adenylyl cyclases to olfaction have not been defined. Here, we report the presence of adenylyl cyclases 2, 3, and 4 in olfactory cilia. To evaluate the role of AC3 in olfactory responses, we disrupted the gene for AC3 in mice. Interestingly, electroolfactogram (EOG) responses stimulated by either cAMP- or inositol 1,4,5-triphosphate- (IP3-) inducing odorants were completely ablated in AC3 mutants, despite the presence of AC2 and AC4 in olfactory cilia. Furthermore, AC3 mutants failed several olfaction-based behavioral tests, indicating that AC3 and cAMP signaling are critical for olfactory-dependent behavior.
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Chan GC, Ma SK, Ha SY, Chan LC, Lau YL. Childhood essential thrombocythaemia without evidence of myeloproliferation: how many investigations should be done? Br J Haematol 2000; 110:1002. [PMID: 11054096 DOI: 10.1046/j.1365-2141.2000.02270.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Wan TS, Ma SK, Ching LM, Chan LC, Chan GC, Ha SY. Translocation (1;13)(p34;q32) in childhood pre-B-cell acute lymphoblastic leukemia. CANCER GENETICS AND CYTOGENETICS 2000; 121:107-8. [PMID: 10991621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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Cheng W, Chan GC, Tam PK. Cytotoxic chemotherapy has minimal direct effect on gastric myoelectric activity in children with 5HT(3) antagonist prophylaxis. MEDICAL AND PEDIATRIC ONCOLOGY 2000; 34:421-3. [PMID: 10842249 DOI: 10.1002/(sici)1096-911x(200006)34:6<421::aid-mpo7>3.0.co;2-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Cancer patients receiving cytotoxic chemotherapy frequently develop nausea and vomiting. The direct effect of chemotherapy on gastric pacemaker is not clear. The objective of this study was to assess the direct interference of gastric electrical activity by chemotherapeutic agents as a possible cause of vomiting using electrogastrography (EGG). PROCEDURE Fasting surface EGGs were recorded in 24 children with malignancy and 24 age-matched controls. All oncology patients received the intravenous prophylatic ondansetron. According to the known emetic potential of the medications they received, the children were divided into mild, moderate, and severe groups. The EGG recordings of oncology patients were segmented into prechemotherapy period, chemotherapy period, and emetic period. The EGG data from each period were collected and analyzed (paired t-test and Mann-Whitney U test). RESULTS There were 24 children (M:F ratio: 14:10), with a mean age of 9.6 years. Eight children vomited during the course of recording (0/3 from the mild group, 2/6 from the moderate group, and 6/15 from the severe group). The average duration of intravenous medication infusion was 7.8 hr (range 2 min to 24 hr). There was no difference between the EGG of normal control and the prechemotherapy EGG of the oncology patients. No difference was detected between the EGG data from the prechemotherapy period and the chemotherapy period. A statistically significant increase in tachygastria was detected in emetic periods (28 episodes, mean duration 5 min; P = 0.01). CONCLUSIONS Insignificant EGG changes during chemotherapy suggest that chemotherapy has a minimal direct effect on gastric pacemaker. Tachygastria seemed to be a secondary effect of vomiting rather than the cause of it. These preliminary findings suggest that efforts to modify gastric electrical rhythm as a means of management of chemotherapy-induced vomiting may be futile. Further studies to identify factors responsible for vomiting are warranted.
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Ma SK, Cheung AN, Choy C, Chan GC, Ha SY, Ching LM, Wan TS, Chan LC. Cytogenetic characterization of childhood hepatoblastoma. CANCER GENETICS AND CYTOGENETICS 2000; 119:32-6. [PMID: 10812168 DOI: 10.1016/s0165-4608(99)00203-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We describe the cytogenetic abnormalities in two cases of childhood hepatoblastoma. The first case was of fetal histology with squamous metaplasia, and cytogenetic study showed an add(5)(q31). Although an association between hepatoblastoma and familial adenomatous polyposis is recognized, the breakpoint in this case is distal to 5q21 and most probably does not involve the APC gene at that location. The second case was of macrotrabecular histology, and cytogenetic study showed an unbalanced translocation in the form of der(4)t(1;4)(q12;q34) in a hyperdiploid clone. Including our case, der(4)t(1;4)(q12;q34) has been recognized in four cases of hepatoblastoma, and it may be the first recurrent translocation in this tumor. Understanding the molecular mechanism and clinical significance of this translocation awaits analysis of more cases.
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Wan TS, Ma SK, Chan GC, Ching LM, Ha SY, Chan LC. Complex cytogenetic abnormalities in T-lymphoblastic lymphoma: resolution by spectral karyotyping. CANCER GENETICS AND CYTOGENETICS 2000; 118:24-7. [PMID: 10731586 DOI: 10.1016/s0165-4608(99)00174-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We describe a case of T-lymphoblastic lymphoma (T-LBL) in a 13-year-old boy in which conventional cytogenetic analysis of lymph node tissue showed complex karyotypic aberrations including add(1p), add(2q), and multiple chromosomal deletions involving 5q, 7p, 7q, 13q, and 16q. Analysis by spectral karyotyping (SKY) refined add(1p) to a paracentric inversion of 1p, and add(2q) to an unbalanced translocation between chromosomes 2 and 4. The chromosomal deletions were simple deletions except del(5q), which was confirmed by SKY to be a cryptic unbalanced translocation between chromosomes 5 and 18. The present report illustrates that SKY technology is useful in identifying subtle translocations and resolving complex karyotypic aberrations in neoplastic disorders.
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So CW, Ma SK, Wan TS, Chan GC, Ha SY, Chan LC. Analysis of MLL-derived transcripts in infant acute monocytic leukemia with a complex translocation (1;11;4)(q21;q23;p16). CANCER GENETICS AND CYTOGENETICS 2000; 117:24-7. [PMID: 10700861 DOI: 10.1016/s0165-4608(99)00136-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
It has been proposed, on the basis of cytogenetic studies and molecular analysis of MLL-derived transcripts in acute leukemia with 11q23 rearrangement, that only one fusion gene transcript present on the der(11) chromosome is critical for leukemogenesis. This view is challenged by a recent observation in a case of leukemia with a complex translocation that results in MLL being fused in-frame to two different partner genes. We investigated a case of infant monocytic leukemia with a complex translocation, (1;11;4)(q21;q23;p16). Molecular studies revealed MLL rearrangement by both fluorescence in situ hybridization and Southern blot analysis, and MLL/AF1q, but not the reciprocal message (i.e., AF1q/MLL), was amplified by polymerase chain reaction. Sequence analysis of MLL/AF1q revealed an in-frame fusion between MLL exon 6 and the breakpoint located six bases upstream of the ATG start site for AF1q. Our data suggest that only one form of MLL fusion gene is implicated in leukemogenesis in our case to t(1;11;4).
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MESH Headings
- Base Sequence
- Bone Marrow Transplantation
- Chromosomes, Human, Pair 1
- Chromosomes, Human, Pair 11
- Chromosomes, Human, Pair 4
- DNA Primers
- DNA-Binding Proteins/genetics
- Female
- Histone-Lysine N-Methyltransferase
- Humans
- Infant
- Karyotyping
- Leukemia, Monocytic, Acute/genetics
- Leukemia, Monocytic, Acute/therapy
- Myeloid-Lymphoid Leukemia Protein
- Proto-Oncogenes
- Transcription Factors
- Translocation, Genetic
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Chan GC, Head DR, Wang WC. Refractory anemia with ringed sideroblasts in children: two diseases with a similar phenotype? J Pediatr Hematol Oncol 1999; 21:418-23. [PMID: 10524457 DOI: 10.1097/00043426-199909000-00015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Three pediatric patients with refractory anemia with ringed sideroblasts (RARS) are presented. Bone marrow aspirates were examined using Romanowsky and Prussian blue iron stains in all three patients, and electron microscopic analysis was performed in one patient. All three patients had cytogenetic analysis of the bone marrow. Other studies included analysis of serum iron, total iron-binding capacity, ferritin, copper, vitamins B6 and B12, and folate levels. Antibody titers to Parvovirus, HIV, and other viruses were measured. The patients had contrasting clinical courses. Patients 1 and 2 had dysplastic hematopoietic features and cytogenetic findings (with either partial or one allele loss of chromosome 7), suggestive of myelodysplastic syndrome. Patient 1 experienced acute myeloid leukemia (AML) and had a good response to AML-directed therapy. Patient 2 had prolonged cytopenias and underwent bone marrow transplantation (BMT). Patient 3 had features suggestive of refractory anemia associated with mitochondrial cytopathy, including normal cytogenetics with pronounced vacuolization of marrow precursors. His anemia regressed spontaneously a few months after diagnosis. These patients represent two subgroups of pediatric RARS. Patients with the myelodysplastic syndrome (MDS) type may progress to cytopenias or leukemia and may require aggressive therapy; the type is characterized by clonal cytogenetic findings. The non-MDS type, which may relate to mitochondrial cytopathy, often shows spontaneous regression and requires only supportive treatment; it has normal cytogenetic findings.
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MESH Headings
- Adolescent
- Anemia, Refractory, with Excess of Blasts/genetics
- Anemia, Refractory, with Excess of Blasts/pathology
- Bone Marrow Cells/pathology
- Bone Marrow Transplantation
- Child
- Chromosomes, Human, Pair 7
- Erythroblasts/pathology
- Erythroblasts/ultrastructure
- Female
- Humans
- Iron/analysis
- Leukemia, Myeloid, Acute/complications
- Leukemia, Myeloid, Acute/therapy
- Loss of Heterozygosity
- Male
- Mitochondria/pathology
- Mitochondria/ultrastructure
- Phenotype
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Shek TW, Luk IS, Peh WC, Chan KL, Chan GC. Metanephric adenofibroma: report of a case and review of the literature. Am J Surg Pathol 1999; 23:727-33. [PMID: 10366157 DOI: 10.1097/00000478-199906000-00014] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The recent recognition of a variety of pediatric renal tumors of different biologic behavior places an ever-increasing demand on the surgical pathologist for an accurate diagnosis. Although metanephric adenofibroma is one of the rarest benign renal tumors, the clinical importance of correctly diagnosing it cannot be overemphasized because it can potentially be mistaken as Wilms' tumor. We describe the clinical, radiologic, and pathologic features of a case of metanephric adenofibroma and discuss its differential diagnosis. The neoplasm was composed of two discrete components: a major fibroblastic element and a minor immature epithelial element. The latter formed a small nodule beneath the renal capsule, which could barely be detected by magnetic resonance imaging. This subcapsular nodule, however, was slightly soft and tan and was distinctly different from the white, whorled cut surface of the main tumor. It was formed by closely packed small immature epithelial cells in a slightly edematous background, which was histologically identical to metanephric adenoma and closely resembled epithelial Wilms' tumor. Unlike Wilms' tumor, however, the epithelial cells were very bland with no mitoses. The main bulk of the tumor was formed by spindle fibroblastic cells that were cytologically similar to the spindle cells in congenital mesoblastic nephroma. The tumor, however, was well demarcated without the irregular infiltrating edges of congenital mesoblastic nephroma. In contrast to the randomly distributed epithelial element throughout the stromal component in previous reported cases of metanephric adenofibroma, our finding of the exceedingly small and discrete epithelial component expands the known histologic spectrum of the disease. In addition, the presence of such minute epithelial nodule underscores the importance of diligent pathologic examination and careful sampling of tissue for histologic examination.
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Chan GC, Ma SK, Ha SY, Sriastava G, Wan TS, Kwong DL, Chan LC, Lau YL. Biphenotypic lymphoblastic non-Hodgkin lymphoma with a balanced translocation t(1;9)(p10;q10): unusual presentation with poor outcome. MEDICAL AND PEDIATRIC ONCOLOGY 1999; 32:450-2. [PMID: 10358707 DOI: 10.1002/(sici)1096-911x(199906)32:6<450::aid-mpo13>3.0.co;2-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Ma SK, Chan GC, Wan TS, Lam CK, Ha SY, Lau YL, Chan LC. Near-haploid common acute lymphoblastic leukaemia of childhood with a second hyperdiploid line: a DNA ploidy and fluorescence in-situ hybridization study. Br J Haematol 1998; 103:750-5. [PMID: 9858226 DOI: 10.1046/j.1365-2141.1998.01044.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Near-haploidy is a rare cytogenetic finding in childhood acute lymphoblastic leukaemia (ALL) and is associated with a poor prognosis. A second hyperdiploid line, occurring presumably by endoreduplication of the near-haploid stemline, is often observed. We present a case of common ALL in relapse characterized morphologically by a dual population of small and large lymphoblasts. Cytogenetic analysis supplemented with fluorescence in-situ hybridization (FISH) studies localized near-haploidy and hyperdiploidy to the small and large blast population respectively. DNA ploidy determination confirmed two abnormal clones with near-haploidy as the predominant one. A novel t(9;12)(q11;q13) was present in the near-haploid clone and was duplicated in the hyperdiploid clone. This finding identified cells bearing near-haploidy to be the clonogenic population following malignant transformation and confirmed endoreduplication as the mechanism for the presence of associated hyperdiploidy.
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Abstract
OBJECTIVES Endogenous carbon monoxide (CO) is produced mainly by heme catabolism. As CO is excreted solely by the lung, a simple technique for measuring the end tidal carbon monoxide (ETCO) level was assessed as a method for screening for haemolytic disease in children. METHODS Two end expiratory breath samples were collected from normal children and from children with haemolytic disease using a one way valve connector between a mouth piece and an anaesthetic bag. The samples were analysed by gas chromatography for CO and carbon for dioxide (CO2). The CO2 value was used to normalise the CO value to an alveolar concentration. Carboxyhaemoglobin (HbCO) also was measured in the patient group for correlation analysis with ETCO. RESULTS A total of 21 children with beta thalassaemia major, 15 children with other haemolytic diseases (hereditary spherocytosis n=8, haemoglobin H disease n=3 and thalassaemia intermedia n=4) and 23 normal children were studied. The mean ETCO concentrations in the three groups were 3.21 p.p.m., 7.41 p.p.m. and 0.69 p.p.m., respectively, which were significantly different from each other (P<0.0001). There was a significant correlation between ETCO and HbCO in the patient groups (r=0.85; P<0.0001). CONCLUSIONS The end expiratory breath collection device is a simple and feasible sample collection method. The results confirm that ETCO can be used clinically to distinguish children with a variety of haemolytic disorders from normal subjects.
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Wei J, Zhao AZ, Chan GC, Baker LP, Impey S, Beavo JA, Storm DR. Phosphorylation and inhibition of olfactory adenylyl cyclase by CaM kinase II in Neurons: a mechanism for attenuation of olfactory signals. Neuron 1998; 21:495-504. [PMID: 9768837 DOI: 10.1016/s0896-6273(00)80561-9] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Acute desensitization of olfactory signaling is a critical property of the olfactory system that allows animals to detect and respond to odorants. Correspondingly, an important feature of odorant-stimulated cAMP increases is their transient nature, a phenomenon that may be attributable to the unique regulatory properties of the olfactory adenylyl cyclase (AC3). AC3 is stimulated by receptor activation and inhibited by Ca2+ through Ca2+/calmodulin kinase II (CaMKII) phosphorylation at Ser-1076. Since odorant-stimulated cAMP increases are accompanied by elevated intracellular Ca2+, CaMKII inhibition of AC3 may contribute to termination of olfactory signaling. To test this hypothesis, we generated a polyclonal antibody specific for AC3 phosphorylated at Ser-1076. A brief exposure of mouse olfactory cilia or primary olfactory neurons to odorants stimulated phosphorylation of AC3 at Ser-1076. This phosphorylation was blocked by inhibitors of CaMKII, which also ablated cAMP decreases associated with odorant-stimulated cAMP transients. These data define a novel mechanism for termination of olfactory signaling that may be important in olfactory responses.
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Jun K, Choi G, Yang SG, Choi KY, Kim H, Chan GC, Storm DR, Albert C, Mayr GW, Lee CJ, Shin HS. Enhanced hippocampal CA1 LTP but normal spatial learning in inositol 1,4,5-trisphosphate 3-kinase(A)-deficient mice. Learn Mem 1998; 5:317-30. [PMID: 10454357 PMCID: PMC311247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
To define the physiological role of IP(3)3-kinase(A) in vivo, we have generated a mouse strain with a null mutation of the IP(3)3-kinase(A) locus by gene targeting. Homozygous mutant mice were fully viable, fertile, apparently normal, and did not show any morphological anomaly in brain sections. In the mutant brain, the IP4 level was significantly decreased whereas the IP3 level did not change, demonstrating a major role of IP(3)3-kinase(A) in the generation of IP4. Nevertheless, no significant difference was detected in the hippocampal neuronal cells of the wild-type and the mutant mice in the kinetics of Ca2+ regulation after glutamate stimulation. Electrophysiological analyses carried out in hippocampal slices showed that the mutation significantly enhanced the LTP in the hippocampal CA1 region, but had no effect on the LTP in dentate gyrus (DG). No difference was noted, however, between the mutant and the wild-type mice in the Morris water maze task. Our results indicate that IP(3)3-kinase(A) may play an important role in the regulation of LTP in hippocampal CA1 region through the generation of IP4, but the enhanced LTP in the hippocampal CA1 does not affect spatial learning and memory.
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