PubMed Health⌕ Search

Biomedical subjects

Satoshi Asai

Publications and source records attributed to Satoshi Asai.

At least 19 recordsLinked to original sources
PubMed2006

Detection of aberrations of ubiquitin-conjugating enzyme E2C gene (UBE2C) in advanced colon cancer with liver metastases by DNA microarray and two-color FISH.

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. There was no significant difference in gene expression between the primary tumors and the liver metastases. The most highly overexpressed gene in both the primary tumors and the liver metastases was the ubiquitin-conjugating enzyme E2C gene (UBE2C), located at 20q13.1. Additionally, two-color FISH analysis using probes for the region 20q13.1 and the chromosome 20 centromere revealed that amplification at 20q13.1 had occurred in 5 of 10 (50%) colon cancers. Comparison between the levels of gene expression and FISH results revealed that UBE2C expression is significantly changed by amplification at 20q13.1, suggesting genomic amplification as one mechanism of increased UBE2C expression. Our results showing aberrations in levels of gene expression and locus copy number of UBE2C suggest that this gene may play an important role in tumor progression leading to advanced colon cancer with liver metastasis.

Centromere↗
PubMed2006

Statistical validation of two sample comparison methods for oligonucleotide microarray in rat ischemia model.

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. In pair-wise comparisons, most of the elements were significantly independent of the threshold value, with the percentage of significant elements remaining above 95%, when screened at 2.5-fold or higher threshold value. Pair-wise comparison structurally provided strict screening, which resulted in genes that were not selected despite significant alterations in expression. Screening by "sample average comparison" resulted in elements with low probability of significance, which suggested the necessity for increasing the reliability by additional statistical analyses after screening. When genes with altered expression were screened using an oligonucleotide array, marked differences in the numbers and reliability were proved to exist among elements screened by each sample comparison method.

Animals↗
PubMed2006

Screening for control genes in mouse hippocampus after transient forebrain ischemia using high-density oligonucleotide array.

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. Using the GeneChip Mu6500 array set, we monitored the expression levels of approximately 6000 murine genes in the mouse hippocampus during 24 h of ischemia-reperfusion. To select stable genes, we applied the restricted criterion of a 1.5-fold change in expression level as the threshold. By adding statistical analysis with this criterion, we identified 10 genes as candidates for control genes from the GeneChip data. In this criterion, GAPDH and beta-actin genes were not included in the 10 genes as candidates for control genes. The present findings might be relevant to the use of control genes in quantitation of RNA, particularly in the study of mouse transient forebrain ischemia.

Animals↗
PubMed2005

Genotype and haplotype association study of the STRK1 region on 5q12 among Japanese: a case-control study.

BACKGROUND AND PURPOSE: Cerebral infarction is thought to be a multifactorial disease that is affected by several environmental factors and genetic variants. Gretarsdottir et al identified a candidate locus (STRK1) for cerebral infarction with a significant logarithm of odds score at 5q12 in whites in 2002 and subsequently identified the PDE4D gene as a susceptibility gene at this locus in 2003. The aims of this haplotype-based case-control study were to confirm, using microsatellite markers and single-nucleotide polymorphisms (SNPs), whether PDE4D is also a susceptibility gene for cerebral infarction in Japanese subjects. METHODS: Cerebral infarction was defined as noncardiogenic ischemic stroke with signs and symptoms lasting >1 month in duration. We genotyped 208 Japanese cerebral infarction patients and 270 non-cerebral infarction controls for 31 SNPs, 3 dinucleotide microsatellites, and 1 tetranucleotide variable number of tandem repeat. Haplotypes were constructed and their frequencies compared between the cerebral infarction patients and the controls. RESULTS: The haplotype-based case-control study revealed that in addition to the region of the PDE4D gene (P=0.002), another region (P<0.001) also existed within the STRK1 locus. CONCLUSIONS: The region of the PDE4D gene and the other newly detected region within the STRK1 locus were associated with cerebral infarction.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2005

Monitoring expression of cytochrome P450 genes during postischemic rat liver reperfusion using DNA microarrays.

We investigated the expression of 50 cytochrome P450 (CYP) genes in the postischemic reperfused rat liver using a DNA microarray. Thirteen CYPs showed absent expression in all experiments and 2 CYPs were induced by pentobarbital, which was used as an anesthetic. Eight of the remaining 35 CYPs showed significantly decreased expression following ischemia-reperfusion. Monitoring CYP expression may be a powerful approach for elucidation of pathways regulating drug metabolism that may be involved in postischemic reperfusion liver injury.

Animals↗
PubMed2005

Osteopontin expression in ulcerative colitis is distinctly different from that in Crohn's disease and diverticulitis.

BACKGROUND: The aim of the present work was to assess osteopontin (OPN) expression in the colon tissues of ulcerative colitis (UC), Crohn's disease (CD), and diverticulitis (Div) patients. METHODS: This study included three groups: the UC group, CD group, and Div group. Immunohistochemical staining was performed, using an immunoperoxidase method. RESULTS: Regarding OPN expression in intestinal epithelial cells, no difference was noted among the three groups. However, in the submucosa of the UC group, the ratio of two types of large cells (oval and spindle-shaped) expressing OPN was 61.2 +/- 14.4% (mean +/- SD), which was significantly higher than that in the CD group (14.9 +/- 7.0%; P < 0.05) and that in the Div group (11.2 +/- 6.1%; P < 0.05). In addition, in the UC group, the ratio of these cells in the subserosa (50.1 +/- 15.0%; mean +/- SD) was significantly higher than that in the CD group (16.9 +/- 6.2%; P < 0.05) and that in the Div group (12.6 +/- 5.7%; P < 0.05). In a serial section study, the oval-shaped cells were stained for anti-CD 68, while the spindle-shaped cells were stained for anti-vimentin. CONCLUSIONS: OPN in two types of large colon-infiltrating cells is possibly related to one of the pathogenic factors of UC.

Antibodies, Monoclonal↗
PubMed2005

Molecular genetic alterations and gene expression profile of a malignant rhabdoid tumor of the kidney.

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 0.29-Mb genomic region bordered by the Rgr and DDT genes in these tumor cells. This deleted region encodes SMARCB1, a candidate tumor suppressor gene for MRTK. Using a high-density oligonucleotide DNA array, we found increased expression of 25 genes, including genes involved in the cell cycle (10 genes), DNA replication (3 genes), cell growth (5 genes), and cell proliferation (5 genes), in this MRTK tumor sample, compared with a noncancerous kidney (NK) sample. On the other hand, 64 genes, including 4 genes regulating apoptosis, were found to show decreased expression in this MRTK tumor sample, compared with the NK sample. Among these alterations, we found alterations of expression of some genes, such as IGF2, MDK, TP53, and TNFSF10, in this MRTK tumor, as described previously. The molecular genetic alterations and altered pattern of gene expression found in this case may have contributed to the biological characteristics of the MRTK tumor that arose in our patient.

Apoptosis↗
PubMed2005

Ornithine breath test as a method to evaluate functional liver volume.

BACKGROUND: The purpose of this study was to investigate whether the functional liver volume can be measured from changes in expiratory 13CO2 levels after intravenous administration of L-[1, 2-13C] ornithine, using a rat model of hepatectomy. MATERIALS AND METHODS: Under pentobarbital anesthesia, 30%, 70%, or 90% hepatectomy was performed. In the control group, simple laparotomy was performed. Then, 20 mg/kg L-[1, 2-13C] ornithine was administered to rats via the femoral vein. A breath test was conducted 20 min after laparotomy. We examined the correlation of the sum of 13CO2 output (S) or a single point of 13CO2 level (SP) with liver weight/body weight (LW/BW) (%) every 15 min. RESULTS: In all of the groups, the ornithine breath test (OBT) graph reached a plateau level at about 6 min. The correlation coefficient between S15 and LW/BW was highest 0.952 (P <0.0001). The correlation coefficient between SP14 and LW/BW was highest, 0.944 (P <0.0001). The severity of hepatic injury could be evaluated, with significant differences in S5-15 and SP5-15 in all comparisons between groups. CONCLUSION: In the breath test with intravenously administered L-[1, 2-13C] ornithine, functional liver volume could be evaluated accurately in a short period.

Animals↗
PubMed2004

Screening for control genes in rat global cerebral ischemia using high-density oligonucleotide array.

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. Screening of more than 8,000 transcripts with the Rat Genome U34A array yielded 28 transcripts, which we listed and classified according to their expression level. Widely used control genes, GAPDH and beta-actin, were not included, although cyclophilin A was included. In addition, we conducted a functional classification based on gene ontology. Under the functional classification of the 28 transcripts, many genes tended to be associated with metabolism. In conclusion, use of several transcripts is recommended, such as those we identified, as references in the analysis of gene expression in pathological models of ischemia.

Animals↗
PubMed2004

Alteration of serum/glucocorticoid regulated kinase-1 (sgk-1) gene expression in rat hippocampus after transient global ischemia.

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. Using in situ hybridization (ISH) analysis, the increased level of sgk-1 gene expression was found to localize in pyramidal cells of CA2 and CA3 regions of the hippocampus after 2 h of reperfusion. These results provide an insight into the alterations of sgk-1 gene expression in the rat hippocampus after transient global cerebral ischemia.

Animals↗
PubMed2004

Profiling of genes associated with transcriptional responses in mouse hippocampus after transient forebrain ischemia using high-density oligonucleotide DNA array.

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 3.0-fold higher or lower level of expression on average, with statistical significance set at p<0.05, in at least one ischemia-reperfusion group than in the sham group. Using unsupervised clustering methods (hierarchical clustering and k-means clustering algorithms), we identified four types of gene expression pattern that may be associated with the response of cell populations in the hippocampus to an ischemic insult in this mouse model. Functional classification of the 25 genes demonstrated alterations of expression of several kinds of biological pathways, regulating transcription (Bhlhb2, Jun, c-fos, Egr1, Egr2, Fosb, Junb, Ifrd1, Neurod6), the cell cycle (c-fos, Fosb, Jun, Junb, Dusp1), stress response (Dusp1, Dnajb1, Dnaja4), chaperone activity (Dnajb1, Dnaja4) and cell death (Ptgs2, Gadd45g, Tdag51), in the mouse hippocampus by 24 h of reperfusion. Using hierarchical clustering analysis, we also found that the same 25 genes clearly discriminated between the sham group and the ischemia-reperfusion groups. The alteration of expression of 25 genes identified in this study suggests the involvement of these genes in the transcriptional response of cell populations in the mouse hippocampus after transient forebrain ischemia.

Analysis of Variance↗
PubMed2004

Gene expression analysis in the stomachs of water immersion-restraint stress rats using high-density oligonucleotide array.

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. We investigated the gastric gene expression profile in response to stress. METHODS: A high-density oligonucleotide array, representing approximately 850 genes, was used to determine gene expression changes in the stomachs of water immersion-restraint stress (WIRS) rats. RESULTS: Fifty-eight genes including expressed sequence tag (EST) genes were upregulated more than twofold in the 30 min-WIRS rat stomach as compared with the control. Concomitantly, five genes were downregulated. Numbers of up- or downregulated genes decreased rapidly at 1 and 2 h of WIRS. Altered gene expression of heat shock proteins, cell cycle regulators, proto-oncogenes and metabolic enzymes were recognized. Several of these genes, including p38 mitogen-activated protein kinase, did not reportedly show gastric expression changes in response to stress. CONCLUSION: These results suggest that, in addition to the previously identified stress-induced genes, expression of a number of other genes in the stomach is also involved in stress response.

Animals↗
PubMed2003

L-[1-13C] phenylalanine breath test reflects phenylalanine hydroxylase activity of the whole liver.

OBJECT: The purpose of this study was to perform L-[1-13C] phenylalanine breath test (PBT), measure phenylalanine hydroxylase (PAH) activity in liver tissue biopsies from patients, analyze the relationship between PBT results and PAH activity, and determine the time point at which measurements best reflect PAH activity in liver tissue. METHODS: PBT was performed in 25 patients (10 with normal liver and 15 with liver cirrhosis). After administering 10 mg/kg L-[1-13C] phenylalanine, 300 ml of expired air was collected over 90 min at 15-min intervals. The rate of hepatic phenylalanine oxidation (%13C dose h(-1)) at each time point was calculated from the amount of 13CO(2) in the breath, assuming a CO(2) production rate of 300 mmol m(-2) body surface area per hour. Subsequently, we examined the relationship between the results of PBT and PAH activity. RESULTS: PAH activity of the whole liver was significantly decreased in hepatic cirrhosis patients (P < 0.05). The results of PBT %13C dose h(-1) correlated with the PAH activity/liver, with correlation coefficients at 30, 45, and 60 min of more than 0.7, and the maximum correlation was at 30 min (r = 0.821, P < 0.0001). %13C cumulative excretion correlated with the PAH activity/liver with correlation coefficients of more than 0.7 after 45 min. The maximum correlation was at 90 min (r = 0.770, P = 0.001). CONCLUSION: PBT values reflect PAH activity in the whole liver and, in particular, the % dose h(-1) at 30 min after oral administration highly correlates with PAH activity, providing an important indicator for monitoring changes in whole liver PAH activity.

Adult↗
PubMed2003

Distinct gene expression of osteopontin in patients with ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) is a multifactorial disorder of unknown etiology. Few studies have applied genome-wide gene expression analysis in colon tissue samples of UC. We report the analysis of mucosal gene expression in UC and noninflamed control specimens. MATERIALS AND METHODS: This study included 7 UC patients who received a total colectomy because of severe total colitis. Normal control colon tissues were obtained at least 10 cm from the area of pathology in 3 colon cancer patients. Ten colonic tissue samples (7 UC and 3 normal control samples) were subjected to high-density oligonucleotide array analysis. To compare differences in the level of gene expression between UC and control samples, Mann-Whitney U-test was used, with significance set at P < 0.05. RESULTS: Twenty-five genes had a 3.0 approximately 23.4-fold higher mRNA expression in UC samples compared with normal samples, whereas three genes had a 3.0 approximately 3.4-fold lower expression in UC samples compared with normal samples. Two genes showing more than a 10-fold increase expression in UC samples were a macrophage metalloelastase (L23808) and a osteopontin (AF052124). It has been said that macrophage metalloelastase is related to ulcer formation of the intestine, whereas osteopontin plays an important role in the pathogenesis of systemic lupus erythematosus and rheumatoid arthritis. CONCLUSION: Our present study supports the previous report that macrophage metalloelastase is related to ulcer formation of UC, and it also indicates the possibility that osteopontin plays an important role in the pathogenesis of UC via increased immune activity.

Adult↗
PubMed2003

Patients with severe liver cirrhosis followed up by L-[1-(13)C] phenylalanine breath test.

Compared to healthy subjects, patients with severe liver cirrhosis (LC) are reported to show lower values in the L-[1-(13)C] phenylalanine breath test (PBT). We performed this test several times during the clinical course in two patients with severe liver cirrhosis (LC). Patient 1 was a 67-year-old woman with non-B, non-C LC and hepatocellular carcinoma (HCC) in the lateral hepatic segment. Because the patient wanted to receive nonsurgical treatment for HCC, intraarterial administration of zinostatin stimalamer was performed. The patient was hospitalized four times before her death from liver failure on December 20, 2000. During her clinical course, PBT was performed four times. Values for both the rate of hepatic phenylalanine oxidation (%(13)C dose h(-1)) and %(13)C cumulative excretion gradually decreased during her clinical course. Patient 2 was a 57-year-old man with hepatitis C virus (HCV)-positive LC. He was hospitalized seven times between December 1998 and his death on May 24, 2001. During his clinical course, PBT was performed four times. Values for both %(13)C dose h(-1) and %(13)C cumulative excretion decreased during his clinical course. We confirmed that PBT was useful for following the course of LC.

Aged↗
PubMed2003

L-[1-13C] phenylalanine breath test reflects histological changes in the liver.

OBJECTIVE: Compared with healthy individuals, patients with chronic liver disease reportedly have lower L-[1-13C] phenylalanine breath test (PBT) values. However, there is no report detailing the relationship between the results of PBT and pathological data in liver disease patients. This study was designed to investigate the degree of histological changes in the liver that induce PBT changes and the time of measurement that reflects the histological change. MATERIALS AND METHODS: PBT was performed in 47 patients (10 with a normal liver, and 37 with chronic hepatitis C). After administering 10 mg/kg L-[1-13C] phenylalanine, 300 mL of expired air was collected over 90 min at 15-min intervals. The rate of hepatic phenylalanine oxidation (%13C dose h(-1)) at each time point was calculated from the amount of 13CO(2) in the exhaled air, assuming a CO(2) production rate of 300 mmol m(-2) body surface area per hour. Subsequently, we examined the relationship between the results of PBT and METAVIR pathological scoring. RESULTS: The highest correlation coefficients between the fibrosis score and %13C dose h(-1) and between the fibrosis score and %13C cumulative excretion were obtained at 45 min (r = -0.779, R(2) = 0.607; P < 0.0001) and 75 min (r = -0.768, R(2) = 0.590; P < 0.0001), respectively. CONCLUSION: PBT is a useful adjunct for detecting histological changes in the liver. The %13C dose h(-1) value at 45 min and the %13C cumulative excretion value at 75 min of PBT are useful for detecting hepatic histological change.

Biomarkers↗
PubMed2003

Transcriptional profiling in hepatoblastomas using high-density oligonucleotide DNA array.

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. Using Mann-Whitney U test followed by the k-nearest neighbor algorithm, we identified 26 genes (predictor genes) that were able to assign unknown samples derived from NDL and HBT to either the NDL group or HBT group with 100% accuracy. Using a cross-validation approach, we confirmed that the k-nearest neighbor algorithm assigned the particular samples derived from NDL and HBT to either the NDL or HBT group with 93.3% (28/30 samples) accuracy. In the 26 predictor genes, we found alteration of the expression of genes regulating cell division (NAP1L1, STMN1, CCNG2, and CDC7L1) and tumor cell growth (IGF2 and IGFBP4) in HBT. Four predictor genes (ETV3, TPR, CD34, and NR1I3) were also found to be mapped to the chromosomal region 1q21 approximately q32, which has been reported to be frequently involved in the development of hepatoblastoma. The findings obtained in this study suggest that alteration of the expression of some genes regulating cell division and tumor cell growth may be characteristics of the gene expression profile in HBT, and that alteration of the expression of the four predictor genes mapped to chromosomal region 1q21 approximately q32 may also contribute to the differences in gene expression profile between NDL and HBT.

Child↗