Biomedical subjects

Satoshi Asai

Publications and source records attributed to Satoshi Asai.

30 records · Page 2Linked to original sources

PubMed2003

Clinical application of oligonucleotide probe array for full-length gene sequencing of TP53 in colon cancer.

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). The expression of TP53 protein was also evaluated immunohistochemically and the result was compared with the gene alteration. RESULTS: The GeneChip p53 assay detected TP53 mutations in 65% of primary cancers; 61% of the mutations were within the evolutionarily conserved regions, and 46% of the mutations were within the zinc-binding domains (regions of loop 2 and loop 3). Direct sequencing confirmed these mutations. Immunohistochemical examination detected TP53 protein overexpression in 47% of primary cancers, but this protein did not accumulate with all types of TP53 mutations. In addition, the GeneChip assay detected a mutation identical to that in the primary tumor in 2 samples from the surgical margins, and MASA confirmed both mutations, implying the presence of occult cancer cells. CONCLUSION: The GeneChip p53 assay is sufficiently sensitive to detect TP53 mutations in surgical specimens from colon cancers and may be applicable to screening examination in clinical laboratories as a routine procedure.

Adult↗

PubMed2003

Haplotype analysis of the human renin gene and essential hypertension.

The human renin gene is an attractive candidate for involvement in the underlying cause of essential hypertension (EH). Despite extensive examination, the relation between the renin gene and hypertension remains unclear. The aims of the present study were to discover new genetic markers of EH and to investigate the relations between polymorphisms of the renin gene and EH in the Japanese. Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method, we isolated 3 novel variants of the renin gene; a single nucleotide polymorphism (SNP) in intron 4 (T+17int4G), a variable number of tandem repeats (VNTR) polymorphism in intron 7, and a missense mutation in exon 9 (G1051A). We performed an association study with these polymorphisms in 212 patients with EH and 209 age-matched normotensive (NT) subjects. The frequency of genotypes VNTR and T+17int4G did not differ significantly between the 2 groups, whereas the overall distribution of G1051A was significantly different between EH and NT. Haplotype analysis revealed that the overall distribution of haplotypes differed significantly between the EH and NT groups. PRA levels in patients with EH with the G/G genotype were significantly higher than in subjects with EH with G/A and A/A genotypes. These data suggest that the missense mutation in exon 9 may affect the enzymatic function of renin and consequently may be involved in the etiology of hypertension.

Adult↗

PubMed2003

Localization of thioredoxin-interacting protein (TXNIP) mRNA in epithelium of human gastrointestinal tract.

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. TXNIP transcript was especially prominent in terminal differentiated cells. TXNIP was also highly expressed in lymphocytes in the lymphoid follicles. Our results suggest a new potential role of TXNIP in the differentiation of epithelial cells and in mucosal immunity of the GI tract.

Aged↗

PubMed2003

A novel variable number of tandem repeat polymorphism of the renin gene and essential hypertension.

The aims of the present study were to find new genetic markers of essential hypertension (EH) and to investigate relationships between EH and polymorphisms of the renin gene. Using single strand conformation polymorphism, we discovered a new variable number of tandem repeat (VNTR) polymorphism in intron 7 that is 18 bp upstream from the boundary with exon 8. Nucleotide sequencing revealed that this VNTR polymorphism is a tandem repeat of the 4-nucleotide sequence TCTG. There were 6 alleles of this VNTR polymorphism, ranging from 7 repeats to 12 repeats. We analyzed the association between EH and this VNTR polymorphism. There was no significant difference in the overall distribution of this VNTR polymorphism between the EH and normotensive subjects. In summary, we discovered a novel VNTR polymorphism in the renin gene, and this polymorphism was not associated with EH.

Adult↗

PubMed2003

Profiling of genes differentially expressed between fetal liver and postnatal liver using high-density oligonucleotide DNA array.

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. Using Mann-Whitney U test followed by k-nearest-neighbors (supervised learning method) and hierarchical clustering (unsupervised learning method) algorithms, we found 33 genes clearly discriminating between the FL group and PNL group. The functional classification of the 33 genes identified was related to several kinds of biological pathways, regulating the cell cycle (PCNA, CDC7L1, CCND3, YWHA1, PKMYT1), DNA replication and repair (RFC4, RECQ2, PCNA, NAP1L1), cell growth (IGF2, IGFBP2, PRSS11), hormonal signals (AR, SRD5A1, NR1I3), and cellular metabolism (E2-EPF, WWP1, CYP2C9, CYP2E1, CYP2A6, CYP2A7, CYP2A13, CYP4F2, CYP3A4, DDT). The results presented herein provide evidence of a differential expression profile of genes regulating the cell cycle, DNA replication and repair, cell growth, regulation of hormonal signals, and cellular metabolism, between FL and PNL in humans. The 33 genes identified in this study are suggested to be useful markers clearly discriminating between FL and PNL using the gene expression profile.

Adult↗

PubMed2002

l-[1-(13)C]Alanine is a useful substance for the evaluation of liver function.

BACKGROUND: Using a rat model of hepatectomy, we investigated whether the severity of hepatopathy could be quantitatively measured from changes in expiratory (13)CO(2) levels after intravenous administration of l-[1-(13)C]alanine. MATERIALS AND METHODS: Under nembutal anesthesia, 20 mg/kg l-[1-(13)C]alanine was administered to rats via the femoral vein, and expiratory (13)CO(2) levels were measured for 15 min. Then, 30, 70, or 90% hepatectomy was performed. In the control group, simple laparotomy was performed. A breath test was conducted 20 min after laparotomy. We examined the correlation of total (13)CO(2) output (S) or single point (13)CO(2) level (SP) every 1 min for 15 min with liver weight/body weight (LW/BW) (%). RESULTS: In the control group, the breath test graph showed a specific peak level about 3 min after administration, but in all groups undergoing hepatectomy, it did not show any peak level during measurement. The correlation coefficient between S(12--15) after l-[1-(13)C]alanine administration and LW/BW was 0.902 (P < 0.0001). The correlation coefficient between SP(7) after l-[1-(13)C]alanine administration and LW/BW was highest, 0.908 (P < 0.0001). The severity of hepatopathy could also be evaluated, with significant differences in S(12-14) compared to control when the volume of resected liver was 30% or greater, but there was no significant difference between the groups undergoing 70 and 90% hepatectomy. However, the severity of hepatopathy could be evaluated, with significant differences in S(15) and SP(7) in all comparisons between groups. CONCLUSION: In the breath test with intravenously administered l-[1-(13)C]alanine, the severity of hepatopathy could be quantitatively evaluated in a short period by measuring S(15) and SP(7).

Alanine↗

PubMed2002

Recovery of liver function in two-third partial hepatectomized rats evaluated by L-[1-13C]phenylalanine breath test.

BACKGROUND: We have previously reported that by means of a breath test with intravenously administered L-[1-13C] phenylalanine (13Cphe), hepatopathy could be quantitatively evaluated by measuring expiratory 13CO2 levels in a short period. It is known that phenylalanine hydroxylase activity (PAHA) plays an important role in phenylalanine metabolism. We examined the relationship between changes in PAHA and the results of the 13Cphe breath test during hepatic regeneration in a rat model of 70% hepatectomy, to assess their usefulness for evaluating hepatic regeneration. METHODS: Male Wistar rats (Shizvoka Laboratory Animal Center, Hamamatsu, Japan) weighing 230 to 290 g were subjected to 70% hepatectomy under anesthesia with sodium pentobarbital. One, 2, 3, 5, 7, and 14 days postoperatively, 30 mg/kg 13Cphe was intravenously injected into the femoral vein, and the increase in exhaled 13CO2 (Delta 13CO2) was measured for 15 minutes. Simple laparotomy was performed in control rats. After the breath test, the regenerated liver was removed and weighed. The amount of DNA, amount of hepatic tissue total protein (TP), and PAHA were determined. RESULTS: The r between liver weight/body weight and PAHA, between DNA and PAHA, and between TP and PAHA were 0.832, 0.720, and 0.758, respectively. Breath test graphs revealed that liver weight/body weight, DNA, and TP showed the best correlations with the peak value of Delta 13CO2 (liver weight/body weight percentage, r = 0.801; DNA, r = 0.660; TP, r = 0.706), and r between PAHA and peak value was 0.638. CONCLUSIONS: These results suggest that measurement of PAHA in regenerated liver is an effective method for following up liver function after hepatic resection. Moreover, the 13Cphe breath test may also be useful to evaluate liver function after partial hepatectomy.

Animals↗

PubMed2002

[Evaluation of liver function with 13C-labelled amino acid using hepatectomized rat model].

UNLABELLED: Using a rat model of hepatectomy, we investigated whether the severity of hepatopathy could be quantitatively measured from changes in expiratory 13CO2 levels after intravenous administration of L-[1-(13)C]phenylalanine, L-[1-(13)C]methionine or L-[1-(13)C]alanine. MATERIALS AND METHODS: Under nembutal anesthesia, 30 mg/kg L-[1-(13)C]phenylalanine, 40 mg/kg L-[1-(13)C]methionine or 20 mg/kg L-[1-(13)C]alanine was administered to rats through the femoral vein, and expiratory 13CO2 levels were measured for 15 min. Thirty percent, 70% or 90% hepatectomy was performed. In the control group, simple laparotomy was performed. RESULTS: The correlation coefficient between total 13CO2 output over 15 min after L-[1-(13)C]phenylalanine administration and liver weight/body weight was 0.883 (P < 0.001). The correlation coefficient between total 13CO2 output over 15 min after L-[1-(13)C]methionine administration and liver weight/body weight was 0.922 (P < 0.001). The correlation coefficient between total 13CO2 output over 15 min after L-[1-(13)C]alanine administration and liver weight/body weight was 0.902 (P < 0.0001). CONCLUSION: In the breath test with intravenously administered L-[1-(13)C]phenylalanine, L-[1-(13)C]methionine, or L-[1-(13)C]alanine, hepatopathy could be quantitatively evaluated by measuring expiratory 13CO2 levels over 15 min.

Alanine↗

PubMed2002

[GeneChip system from a bioinformatical point of view].

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. Techniques for data construction ("wet" experimental techniques), which are the major components in the GeneChip system, are generally established as routine work in the first screening process in most laboratories worldwide. The most important point would be how we exchange experimental data produced by researchers and gene/genome information available both on the public and the commercial bases so that we reduce useful information on gene expression. Recently, the center of the research has been shifting to computing technology for data processing ("bioinformatics"). This article separately deals with gene expression analysis and genomic analysis, with emphasis on bioinformatics. We describe the data on gene expression screening, the gene targeting process, the analysis of genomic DNA mutations using the P53 probe array, and the HuSNP mapping assays, by presenting our experimental examples.

Computational Biology↗

PubMedDate not supplied

Papillary serous carcinoma of the peritoneum with paraaortic lymph node metastasis despite minimal intraperitoneal involvement: a case report.

UNLABELLED: BACKGROUND; Papillary serous carcinoma of the peritoneum (PSCP) is a tumor that produces widespread intraperitoneal lesions. Unlike serous ovarian adenocarcinoma, many aspects of its mode of progression and biologic characteristics are unclear. CASE: A 46-year-old woman with PSCP had no detectable ascites and minimal intraperitoneal involvement at the time of the diagnosis, but a paraaortic lymph node metastasis was present. Preoperative endometrial cytology was positive (suspicion of adenocarcinoma). The histologic diagnosis was poorly differentiated serous adenocarcinoma. Cytology of the peritoneal washings demonstrated positive findings, similar to those of endometrial cytology. After cytoreductive surgery, including lymph node dissection and platinum-based chemotherapy, the patient achieved long-term survival. CONCLUSION: PSCP can present with an early paraaortic lymph node metastasis. Endometrial cytology can be valuable in the diagnosis.

Adnexa Uteri↗

PubMedDate not supplied

Up-regulation of vitamin D3 up-regulated protein 1 gene in response to 5-fluorouracil in colon carcinoma SW620.

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. TaqMan RT-PCR assay confirmed that VDUP1 gene expression was significantly increased after 24 h of 5-FU treatment compared with untreated control (p<0.01). Moreover, the expression of vitamin D3 receptor, thymidylate synthase (TS), and E2F1 did not change within 24 h of 5-FU treatment, suggesting a different gene-regulatory pathway from that of VDUP1. Recent studies have gradually clarified the potential role of VDUP1 via interaction with TRX in an anti-tumor effect. Therefore, VDUP1 not only may be induced by stress response as a result of 5-FU cytotoxicity, but may also play a key role in 5-FU cytotoxicity in colon cancers. Our experiment using a microarray and TaqMan RT-PCR assay, together with previous reports, provides new insight into a potential mechanism of 5-FU cytotoxicity.

Antimetabolites, Antineoplastic↗

PubMedDate not supplied

Vitamin D3 up-regulated protein 1 (VDUP1) expression in gastrointestinal cancer and its relation to stage of disease.

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. TaqMan RT-PCR assay showed that VDUP1 expression in colorectal and gastric cancers was significantly lower than that in their adjacent normal tissues (p < 0.0001 and p < 0.001, respectively). In addition, we found that VDUP1 expression was associated with clinical stage in colorectal cancer (p < 0.01). VDUP1 expression in stage II patients was significantly higher than that in stage III (p < 0.05) and in stage IV patients (p < 0.01). These results suggest a possible role of VDUP1 in the pathogenesis of gastrointestinal cancer, as well as its clinical significance.

Adult↗