Publications by authors named "Toshihito Nagata"

Mild to moderate differences in brain temperature are known to greatly affect the outcome of cerebral ischemia. The impact of brain temperature on ischemic disorders has been mainly evaluated through pathological analysis. However, no comprehensive analyses have been conducted at the gene expression level.

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In gene expression analyses using a high-density oligonucleotide array in a rat ischemia model, two comparison methods, "pair-wise comparison" and "sample average comparison", were evaluated based on statistical methods. The reliability of the elements screened with a 1.2 to 10-fold threshold was also evaluated.

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Using DNA microarrays, the expression profiles of 1,700 genes in the primary tumor, liver metastases and paired normal tissue obtained from nine patients with advanced colorectal cancer was studied. Twenty genes were upregulated and only one gene was downregulated in the primary tumors. In the liver metastases, 39 genes were upregulated and only three genes were downregulated.

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In conventional relative gene expression analysis (Northern blotting, RT-PCR, and in situ hybridization), housekeeping genes such as the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-actin genes, whose expression levels are considered stable, have been used as control genes for normalization of RNA quantitation. However, it has been reported that the expression levels of these two control genes are affected by ischemia. Therefore, we have been searching for novel control genes whose expression levels are stable in a mouse model of transient forebrain ischemia.

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Malignant rhabdoid tumor of the kidney (MRTK) is a rare but highly aggressive tumor in children, and knowledge about the molecular signature of this tumor is limited. We report the molecular genetic alterations and gene expression profile of an MRTK tumor that arose in a 4-month-old Japanese girl. Fluorescence in situ hybridization and Southern blot analyses revealed a homozygous deletion of an approximately 0.

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Two cases of hepatoblastoma with unique karyotypic changes are described. One case was that of a 2-year-old boy with an unbalanced chromosomal translocation involving 4q35 as the sole chromosomal abnormality. The clonal karyotype of this tumor was 46,XY,add(4)(q35)[3]/46,XY[9].

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Background And Aim: Research on gastric lesions developing in response to stress is essential to elucidating the pathogenesis of these lesions as well as the interplay with other factors, including Helicobacter pylori infection and non-steroidal anti-inflammatory drug use. Genes expressed individually or in sets, such as heat shock proteins, growth factors, proto-oncogenes and cyclooxygenases, have been investigated in the stomach. However, gene expression in the stomach after stress exposure have not yet been comprehensively examined.

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The authors describe a 15-year-old boy with hepatosplenic gammadelta T-cell lymphoma associated with hemophagocytic syndrome (HPS) along with isochromosome 7q and trisomy 8. He presented with prolonged fever, mild anemia, thrombocytopenia, and hepatosplenomegaly. Physical examination, radiography, and ultrasound tomography revealed no lymphoadenopathy.

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From conventional relative gene expression analyses (Northern blotting, in situ hybridization, and RT-PCR), it has been reported that the expression of control genes, such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-actin, used as references may be affected by ischemia. Therefore, we extended searching and evaluation at the mRNA level of transcripts whose expression levels were not changed by cerebral ischemia, using a high-density oligonucleotide array and statistical analysis in a rat global cerebral ischemia and reperfusion model. We added a hyperthermic factor and localization factor to ischemia and identified transcripts with a stable expression level under conditions even more disadvantageous than ischemia only.

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Expression of the serum/glucocorticoid regulated kinase-1 (sgk-1) gene has been reported to be induced by various stress stimuli such as hyper- or hypo-osmotic stress, UV irradiation, and heat shock stress; however, its association with global ischemia in the brain has not been studied. Using high-density oligonucleotide array analysis, we found that the sgk-1 gene was one of the genes showing alteration of expression in the rat hippocampus during 1-4 h of reperfusion after 10 min of transient global cerebral ischemia. Using TaqMan RT-PCR analysis, we confirmed an increased level of sgk-1 gene expression with statistical significance in the rat hippocampus at 2 h of reperfusion after 10 min of transient global cerebral ischemia.

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Several cascades of changes in gene expression have been shown to be involved in the neuronal injury after transient cerebral ischemia; however, little is known about the profile of genes showing alteration of expression in a mouse model of transient forebrain ischemia. We analyzed the gene expression profile in the mouse hippocampus during 24 h of reperfusion, after 20 min of transient forebrain ischemia, using a high-density oligonucleotide DNA array. Using statistical filtration (Welch's ANOVA and Welch's t-test), we identified 25 genes with a more than 3.

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Hepatoblastoma is a common hepatic tumor in children. Although evidence regarding cytogenetic and molecular genetic alterations in hepatoblastomas has been reported, the molecular events affecting the biologic characteristics of this tumor, including alterations of the gene expression profile, are largely unknown. To identify genes differentially expressed between nondiseased liver (NDL) and hepatoblastoma tumor (HBT), we analyzed the gene expression profile in 14 NDL and 16 HBT samples using a high-density oligonucleotide DNA array.

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Thioredoxin-interacting protein (TXNIP) is a negative regulator of thioredoxin. However, its role in the gastrointestinal (GI) epithelium is as yet unknown. Using in situ hybridization, we demonstrated that mRNA of TXNIP was differentially expressed in the epithelium of the human GI tract.

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The liver is an essential organ in humans not only for the production and storage of energy but also for detoxification of chemical compounds, but knowledge about changes in the gene expression profile in the human liver during the prenatal and postnatal periods is limited. Profiling of genes differentially expressed between the fetal liver (FL) and the postnatal liver (PNL) is one of the methods to investigate candidates affecting the difference in biological characteristics between FL and PNL. To identify genes differentially expressed between FL and PNL (childhood and adult liver), we analyzed the gene expression profiles across 9 FL and 14 PNL samples using a high-density oligonucleotide DNA array.

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Decreased expression of VDUP1, which is an interesting stress response gene, has been shown in rat mammary tumors and has been discussed in relation to the development of the tumor. However, VDUP1 expression in clinical specimens of human cancer remains unclear. We employed TaqMan RT-PCR assay to investigate VDUP1 expression in surgical specimens of primary tumors and their adjacent normal tissues from gastrointestinal cancer patients, 40 with colorectal and 12 with gastric cancers.

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Objective: TP53 mutations are the most frequent genetic alterations in colon cancer. We studied whether the recently developed oligonucleotide microarray technique, GeneChip p53 assay, can be applied to sensitive detection of TP53 gene mutations in surgical specimens from colon cancer patients.

Methods: TP53 gene mutations in exons 2-11 in 20 colon cancers and the corresponding histopathologically normal mucosa at the surgical margins were assessed by GeneChip p53 assay, and the results were further evaluated by direct sequencing of the involved exon or by mutant-allele-specific amplification (MASA).

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GeneChip (Affymetrix, Inc., USA) employs a specific method for spotting DNA probes on chips, which is different from any other DNA chips, and can complete the whole process from sample preparation to data construction and analysis. The GeneChip system can be applied to both gene expression analysis and genomic mutation analysis, which would play an important role in human genome analysis in the future.

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Despite the wide use of 5-fluorouracil (5-FU) for colon cancer, the genes regulating its cytotoxic effect are poorly understood. We used a high-density oligonucleotide microarray representing approximately 7000 genes to determine changes in gene expression caused by 5-FU treatment in the colon cancer cell line, SW620. The microarray showed that the most strongly up-regulated gene by 5-FU was vitamin D3 up-regulated protein 1 (VDUP1), an interesting stress response gene, which was originally reported as a vitamin D3 inducible gene in HL-60.

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