Search PubMed⌕ Search

Biomedical subjects

S Ohwada

Publications and source records attributed to S Ohwada.

At least 37 records · Page 2Linked to original sources
PubMed2001

Mutational analysis of the Smad6 and Smad7 genes in hepatocellular carcinoma.

Resistance to the transforming growth factor-beta (TGF-beta) is a frequently found phenotype in human malignancies. The recent identification of Smad6 and Smad7, both anti-Smads which inhibit TGF-beta signaling, raises a possibility that constitutive activation of the anti-Smads by a somatic mutation may impair the TGF-beta signaling pathway. We tested this hypothesis by screening the entire coding sequences of these anti-Smads for mutations in 52 hepatocellular carcinoma (HCC) samples using polymerase chain reaction - single strand conformation polymorphism analysis. We detected no mutations, but found 3 single nucleotide polymorphisms (SNPs) in the Smad6 gene and 2 SNPs in the Smad7 gene. These results suggest that mutations of the Smad6 and Smad7 genes are not the main cause of the TGF-beta resistance in human HCC.

Alleles↗
PubMed2000

Inhibition of Wnt signaling by ICAT, a novel beta-catenin-interacting protein.

Wnt signaling has an important role in both embryonic development and tumorigenesis. beta-Catenin, a key component of the Wnt signaling pathway, interacts with the TCF/LEF family of transcription factors and activates transcription of Wnt target genes. Here, we identify a novel beta-catenin-interacting protein, ICAT, that was found to inhibit the interaction of beta-catenin with TCF-4 and represses beta-catenin-TCF-4-mediated transactivation. Furthermore, ICAT inhibited Xenopus axis formation by interfering with Wnt signaling. These results suggest that ICAT negatively regulates Wnt signaling via inhibition of the interaction between beta-catenin and TCF and is integral in development and cell proliferation.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Frequent chromosome 8q gains in human small cell lung carcinoma detected by arbitrarily primed-PCR genomic fingerprinting.

The arbitrarily primed-polymerase chain reaction (AP-PCR) genomic fingerprinting method was applied to detect chromosomal numerical imbalances in 13 small cell lung carcinomas (SCLC). Increases and decreases in the intensity of the AP-PCR bands from several chromosomes, representing gains of chromosomes 1, 7, 16, and X, and losses of chromosomes 2, 10, and 22, were recurrent events in independent tumors. In addition, the most common alterations detected were increases in signal intensity of three AP-PCR bands derived from genomic sequences on chromosome 8q (eight of 13 tumors: 62%). To define whether the 8q gains observed in the AP-PCR analysis include the C-MYC gene at chromosome 8q24 or not, we performed targeted AP-PCR analysis of the C-MYC gene. The C-MYC gene was amplified in five of the eight tumors with gains of 8q, but in none of the remaining five tumors in which 8q gains were not detected. These results indicate that chromosome 8q gain occurs frequently in SCLC and gained regions often, but do not always, include the C-MYC gene. Moderate increases in copy number of the C-MYC gene and additional gene(s) in the 8q region appear to be under positive selection during SCLC progression.

Carcinoma, Small Cell↗
PubMed2000

Somatic mutations and genetic polymorphisms of the PPP1R3 gene in patients with several types of cancers.

Recently, we found nonsense and missense mutations of the PPP1R3 (protein phosphatase 1, regulatory subunit 3) gene in diverse human cancer cell lines and primary lung carcinomas, indicating that PPP1R3 functions as a tumor suppressor in human carcinogenesis. In this study, to assess the prevalence of PPP1R3 mutations in human primary cancers and the genetic diversity of the PPP1R3 gene in the human population, somatic mutations and genetic polymorphisms in the PPP1R3 gene were examined in 137 pairs of cancerous and non-cancerous tissues of patients with cancers of colon, ovary, and liver. Five somatic mutations including two missense mutations were detected in three cancerous tissues consisting of two colorectal carcinomas and one ovarian carcinoma. Five novel single nucleotide polymorphisms (SNPs) associated with the substitution of amino acids were also identified in cancer patients, in addition to five known nonsynonymous SNPs, including three previously reported ones as having an impact on the susceptibility to insulin resistant disorders. Differences in the activities and properties of multiple PPP1R3 proteins, which are produced in human cells due to variable somatic mutations and genetic polymorphisms in the PPP1R3 gene, can be involved in human carcinogenesis and susceptibility to diseases.

Amino Acid Substitution↗
PubMed2000

Absence of p51 mutation in human hepatocellular carcinoma.

The p51 gene encodes a protein with significant homology to p53. To investigate the involvement of the p51 gene in human hepatocarcinogenesis, mutation analysis of the p51 gene was performed in 54 cases of hepatocellular carcinoma (HCC). No mutations causing amino acid substitutions or frameshifts were found by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis of the entire coding region. The result indicated that mutation of the p51 gene does not play a major role in the development of HCC in Japanese patients. Further studies on p51 expression and its functions, including the interaction with p53, are necessary to elucidate the role of the p51 gene in human hepatocarcinogenesis.

Carcinoma, Hepatocellular↗
PubMed2000

FR167653 ameliorates pulmonary damage in ischemia-reperfusion injury in a canine lung transplantation model.

BACKGROUND: Interleukin (IL)-1 and tumor necrosis factor-alpha (TNF-alpha) are recognized as important factors in ischemia-reperfusion (I/R) injury. FR167653 has been characterized as a potent suppressant of IL-1 and TNF-alpha production. We previously reported that FR167653 suppressed the expression of IL-1 beta mRNA after reperfusion and ameliorated pulmonary I/R injury following 3-hour left lung warm ischemia in dogs. The aim of this study was to investigate the effects of FR167653 on I/R injury in a canine left, single, lung transplantation model. METHODS: We used 10 pairs of weight-matched dogs. We assigned 5 pairs to the FR group, in which each animal received FR167653 (1 mg/kg/hr) IV from 30 minutes before ischemia until 2 hours after reperfusion; we treated the transplanted lungs with FR167653 after the onset of reperfusion. The others were assigned to the control group. After 8-hour preservation with 4 degrees C Euro-Collins solution, orthotopic left, single, lung transplantation was performed. During a 5-minute clamping test at the right pulmonary artery of each recipient, the left (transplanted) pulmonary arterial pressure (L-PAP), left (transplanted) pulmonary vascular resistance (L-PVR), arterial oxygen pressure (PaO(2)), and alveolar-arterial oxygen pressure difference (A-aDO(2)) were measured. We harvested transplanted lung specimens for histologic study, and we counted polymorphonuclear neutrophils (PMNs), which were identified by staining with naphthol AS-D cholroacetate esterase. Pulmonary perfusion and ventilation scintigraphy (Tc-99m-MAA and Xe-133) were performed. We observed the animals for 3 days after transplantation. RESULTS: The PAP, L-PVR, PaO(2), and A-aDO(2) revealed significantly (p < 0.05) better function in the FR group than in the control group. Histologically, lung edema was milder, and PMN infiltration was significantly (p < 0.05) lower in the FR group than in the control group. Xe-133 and Tc-99m-MAA were widely distributed throughout the graft lung in the FR group. Three-day survival rates in FR and control groups were 60% and 20%, respectively. CONCLUSIONS: FR167653 appears to generate a protective effect on I/R injury in lung transplantation in dogs.

Animals↗
PubMed2000

Beneficial effects of novel nitric oxide donor (FK409) on pulmonary ischemia-reperfusion injury in rats.

BACKGROUND: Nitric oxide (NO) seems to play an important role in tissue injury during reperfusion of the lung. FK409 is the first spontaneous NO donor that increases plasma guanosine 3':5'-cyclic monophosphate. It is reported that FK409 prevented myocardial infarction following occlusion and reperfusion in rat coronary arteries. In this study, we evaluated the effects of FK409 on pulmonary ischemia-reperfusion injury in an in situ warm ischemia model of rats. METHODS: Animals were divided into 2 groups: the FK409 study group that was administered FK409 (0.4 mg/kg) before reperfusion and the control group, administered a saline vehicle only. Following a thoracotomy, the bronchus, pulmonary artery and vein were separately clamped for 1 hour. Arterial oxygen tension (PaO2), arterial oxygen saturation (SaO2), and endothelin-I (ET-I) were measured after 2 hours of reperfusion. Histologic and immunohistochemical studies were performed; polymorphonuclear neutrophils (PMNs) were counted after 2 hours of reperfusion. RESULTS: PaO2, SaO2, ET-I after 2 hours of reperfusion and the 7-day survival rate were significantly (p < 0.05) better in the FK409 group than the control group. Histologic damage was reduced in the FK409 group compared with the control group. PMN infiltration was also significantly (p < 0.05) lower in the FK409 group than in the control group. CONCLUSION: FK409 seems to protect against ischemia-reperfusion injury of the lung. This effect may be related to a homeostatic effect on pulmonary vascular beds and prevention of PMN sequestration.

Animals↗
PubMed2000

The effect of FK409-a nitric oxide donor-on canine lung transplantation.

BACKGROUND: Nitric oxide (NO) is known to have beneficial effects in ischemia-reperfusion (I/R) injury through maintaining endothelial integrity, inhibiting leukocyte adhesion and platelet aggregation, and inducing vasodilation. The effect of FK409 (FK), a spontaneous NO donor, was investigated in a canine lung transplantation model. METHODS: Ten pairs of weight-matched dogs were used. Five pairs were assigned to the FK group, to which FK (5 microg/kg/min) was administered intravenously from 30 minutes prior to ischemia until the induction of ischemia in the donor, and from 15 minutes prior to reperfusion until 45 minutes after reperfusion in the recipient. The others were assigned to the control group. After 8-hour preservation in 4 degrees C Euro-Collins solution, orthotopic single-lung transplantation was performed. During a 5-minute clamping test of the right pulmonary artery, left pulmonary arterial pressure (L-PAP), left pulmonary vascular resistance (L-PVR), arterial oxygen pressure (PaO(2)), and alveolar-arterial oxygen pressure difference (A-aDO(2)) were measured. The lung specimens were harvested for histologic study, and polymorphonuclear neutrophils (PMNs) were counted. Pulmonary perfusion and ventilation scintigraphy (Tc-99m-MAA and Xe-133) were performed. RESULTS: PAP, L-PVR, PaO(2), and A-aDO(2) revealed significantly (p < 0.05) better function in the FK group than in the control group. Histologically, edema was more mild, and PMN infiltration was significantly (p < 0.05) lower in the FK group than in the control group. Xe-133 and Tc-99m-MAA were widely distributed throughout the graft lung in the FK group. The 2-day survival rate was 100% in the FK group, which was significantly (p < 0.05) better than the rate (40%) in the control group. CONCLUSIONS: FK appears to generate a protective effect on I/R injury in lung transplantation.

Animals↗
PubMed2000

Optimal end point of FR167653 administration and expression of interleukin-8 messenger RNA on extended liver resection with ischemia in dogs.

BACKGROUND: FR167653 is a potent suppressant of interleukin-1 and tumor necrosis factor production. We previously reported that FR167653 inhibited the expression of interleukin-1 messenger RNA (mRNA) after ischemia-reperfusion and provided a protective effect against ischemia-reperfusion injury after extended liver resection. In this study we investigated the optimal end point of FR167653 administration and the inhibition of interleukin-8 (IL-8) mRNA expression caused by the administration of FR167653 during extended liver resection with ischemia in a dog model. STUDY DESIGN: The right portal pedicle was clamped for 60 minutes but the left portal vein was left patent to avoid portal congestion. After reperfusion 75% of the liver was resected. EXPERIMENT I: Adult mongrel dogs were divided into three groups: the control group (n = 9); the FR-2 group (n = 6), which received FR167653 through the portal vein starting 30 minutes before the onset of ischemia until 2 hours after reperfusion; and the FR-6 group (n = 6), which received FR167653 starting 30 minutes before ischemia until 6 hours after reperfusion. Hepatic venous blood was collected to measure liver enzymes. Liver specimens were harvested for histologic study 6 hours after reperfusion and polymorphonuclear neutrophils were counted. EXPERIMENT II: The expression of IL-8 was measured by reverse-transcriptase polymerase chain reaction. RESULTS: Aspartate aminotransferase and alanine aminotransferase levels after reperfusion and hyaluronic acid levels 6 hours after reperfusion were significantly (p < 0.05) lower in the FR-2 and FR-6 groups than in the control group. There were no significant differences between the FR-2 and FR-6 groups after reperfusion. Histologically liver tissue damage was mild in the FR-2 and FR-6 groups, and polymorphonuclear neutrophil infiltration was significantly lower in the FR-2 and FR-6 groups than in the control group. The 3-day survival rate was statistically (p < 0.05) better in the FR-2 and FR-6 groups than in the control group. IL-8 mRNA expression was inhibited in the FR-treated group. CONCLUSIONS: FR167653 should be administered until shortly after reperfusion and need not be administered for many hours after reperfusion. FR167653 inhibits IL-8 mRNA production and inhibits polymorphonuclear neutrophil infiltration.

Alanine Transaminase↗
PubMed2000

Minute squamous cell carcinoma of the gallbladder: a case report.

Following a simple cholecystectomy, a 63-year-old woman with gallstones was histologically diagnosed as having minute squamous cell carcinoma of the gallbladder. A laparotomy revealed a small, firm nodule that appeared to be an adenoma, which was palpated in the fundus of the gallbladder. The resected gallbladder contained 37 small stones and a small and firm mass (0.4 x 0.4 x 0.3 cm in size) on the mucosal side. Histologically, a pure type of well-differentiated squamous cell carcinoma of the gallbladder was diagnosed. To our knowledge, this is the first case of a minute and pure type of squamous cell carcinoma in the gallbladder. This case may have implications for the histogenesis of squamous cell carcinoma of the gallbladder.

Adenoma↗
PubMed2000

Effects of transfusion on gastrointestinal anastomotic wound healing and leukocyte function in rats.

BACKGROUND: This study was done to investigate the effects of blood transfusion on gastrointestinal anastomotic wound healing and leukocyte function. METHODS: Closed-colony male Wistar rats were divided into five groups in a group-mixed fashion and underwent laparotomy (the CONT and WB groups) or gastrectomy and gastroduodenostomy (the GAST, GAST/WB and GAST/LDRWB groups). Immediately, they received 3 ml of saline (the CONT and GAST groups) or blood from Wistar donors (the WB and GAST/WB groups, whole blood; the GAST/LDRWB group, a transfusion of irradiated and leukocyte-depleted whole blood). The animals were killed 7 days after surgery. RESULTS: The GAST/WB group had a higher incidence of anastomotic abscess, a lower level of factor XIII and a lower maximum breaking strength than the GAST group. Gastrectomy decreased L-DCL (luminol-dependent chemiluminescence) more than whole-blood transfusion. In the GAST/WB group, L-DCL was severely reduced, while in the GAST/LDRWB group it was roughly equivalent to the level in the GAST group. CONCLUSIONS: Whole-blood transfusion increased the incidence of anastomotic abscess and impaired anastomotic wound healing, and these might relate to the reduction of L-DCL. Irradiated and leukocyte-depleted transfusion can improve these effects.

Anastomosis, Surgical↗
PubMed2000

Two regions of homozygous deletion clusters at chromosome band 9p21 in human lung cancer.

We examined 149 lung cancer cell lines for homozygous deletions using 24 DNA markers, which were mapped and ordered in chromosome band 9p21, to define the target regions for 9p21 deletions in human lung cancer. Homozygous deletions were detected in 39 (26%) cell lines and clustered at 2 independent regions. One was the region containing the p16/CDKN2A tumor suppressor gene, and this region was deleted in 32 (21%) cell lines. The other was the region containing D9S171, which is the locus approximately 3 Mb proximal to the CDKN2A locus. This region, designated as the D9S171 region, was deleted in 18 (12%) cell lines. Seven of the 18 cell lines had identical minimum deletions of a 17,036 bp sequence located 20 kb distal to the D9S171 locus. However, such a deletion was also observed in the corresponding B-lymphoblastoid cell line from 1 of the 7 cell lines and in 5 (16%) of 32 noncancerous tissues, suggesting that the deletion was a genetic polymorphism. By considering this polymorphism, 11 (7%) cell lines still had deletions at the D9S171 region. Two NSCLC cell lines showed deletions at the D9S171 region and retentions of the CDKN2A locus. Furthermore, an NSCLC cell line showed discontinuous deletions including either the CDKN2A or D9S171 locus. Therefore, the region surrounding the D9S171 locus was defined as another target region for the 9p21 deletions. It is possible that unknown tumor suppressor gene(s) are present in this chromosomal region. Genes Chromosomes Cancer 27:308-318, 2000.

Carcinoma, Non-Small-Cell Lung↗