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Biomedical subjects

A Ochiai

Publications and source records attributed to A Ochiai.

At least 109 records · Page 6Linked to original sources
PubMed1997

Combined analysis of microsatellite instability and K-ras mutation increases detection incidence of normal samples from colorectal cancer patients.

Microsatellite instability (MI) and K-ras oncogene mutation have been widely used as biomarkers of genetic changes in colorectal cancer (CRC). Each of these biomarkers was independently found in normal-appearing colonic mucosa at stages preceding the development of CRC, albeit at a relatively low incidence. To assess the potential value of combined MI and K-ras mutation analysis in the detection of normal-appearing colonic mucosa samples taken from patients with CRC, we have chosen to analyze multiple (3-7) normal colonic mucosa samples and the respective colorectal tumor tissues from 20 patients with CRC. As a control, we have used 54 normal mucosa samples obtained from 9 autopsies of patients without CRC. In at least 1 of 5 loci analyzed, MI was found in 8 of 20 patients via analysis of multiple normal-appearing colonic mucosa samples from each patient. Combined analysis of MI and mutant ras alleles in normal-appearing colonic mucosa samples enabled the identification of 11 of 20 patients with CRC. None of the 54 normal colonic mucosa samples obtained from 9 patients without CRC were found to carry mutant ras or MI. The ability to detect 55% of patients with CRC via the analysis of normal mucosa samples provides an important advance in our approach toward early detection of individuals who may be at risk to develop this tumor type.

Aged↗
PubMed1997

Tumor growth and metastasis of human colorectal cancer cell lines in SCID mice resemble clinical metastatic behaviors.

Ten human colorectal cancer (CRC) cell lines were implanted orthotopically into the ceca and also into the livers, muscles and peritoneal cavities of SCID mice in order to analyze the characteristics regulating metastatic behaviors of CRCs. All the CRC cell lines formed tumors in the muscle and cecum, but they could be classified into two groups: (1) six cell lines with high tumorigenicity in the liver (HTLs) forming differentiated tumors, and (2) four with no tumorigenicity in the liver (NTLs) forming poorly differentiated tumors in SCID mice. After orthotopic implantation, NTLs never metastasized to the liver, whereas HTLs did. Therefore, intrahepatic tumorigenicity and differential status were closely associated with liver metastasis whereas differentiation was not associated with lung metastasis. The 6 HTLs demonstrated an inverse correlation between liver metastases and peritoneal dissemination, and immunohistochemistry indicated expression of sLeX, CA19-9 and carcinoembryonic antigen in tumors which correlated well with the liver metastatic rate. We found a strong correlation between liver metastasis and intrahepatic tumorigenicity and could reproduce the clinical correlations between the pattern of the metastatic spread and the differentiation phenotype of CRC in vivo. We consider further examination using this model will be useful for analyzing the complex mechanisms involved in clinically metastasizing CRCs.

Adenocarcinoma↗
PubMed1996

Dominant negative inhibition of the association between beta-catenin and c-erbB-2 by N-terminally deleted beta-catenin suppresses the invasion and metastasis of cancer cells.

Aberrant tyrosine phosphorylation of beta-catenin inactivates the E-cadherin-mediated cell adhesion and invasion suppressor system in cancer cells. Elucidation of the association between beta-catenin and c-erbB-2 protein prompted us to investigate whether interference with this interaction can change the invasive phenotype. In a human gastric cancer cell line, TMK-1, N-terminally deleted beta-catenin, which binds to c-erbB-2 but not to cadherin, inhibited the association between endogenous beta-catenin and c-erbB-2 protein, and suppressed the tyrosine phosphorylation of beta-catenin. Cells expressing truncated beta-catenin exhibited markedly reduced invasiveness in vitro and peritoneal metastasis in vivo, and developed an epithelial morphology. These results suggest that tyrosine phosphorylation of beta-catenin regulated by c-erbB-2 protein may play an important role in the invasion, metastasis and morphogenesis of cancer cells and that inhibition of the aberrant tyrosine phosphorylation of beta-catenin effectively prevents invasion and metastasis of cancer cells.

Animals↗
PubMed1996

Alteration of beta-catenin expression in colonic epithelial cells of familial adenomatous polyposis patients.

It has been found that beta-catenin, a key regulator of the cadherin-mediated cell adhesion system, forms complexes with adenomatous polyposis coli (APC) tumor suppressor protein, and beta-catenin expression levels are affected by exogenously induced APC protein. The effects of intrinsic APC protein alteration on beta-catenin expression levels and its subcellular localization were examined in colonic epithelia of eight patients with familial adenomatous polyposis. In all eight patients, beta-catenin was immunostained at the membranes of the cell-to-cell borders in normal epithelial cells, whereas the nuclei and cytoplasms stained intensely in addition to the membranes in both adenoma and cancer cells. beta-Catenin expression levels in tumor tissues were over three times higher than those in corresponding normal mucosae of all of the three patients, whose resected specimens were available for quantitative immunoblot analysis. In these three patients, mutant truncated APC proteins were detected and shown to have lost the central region, including a known beta-catenin binding domain. beta-Catenin was not coimmunoprecipitated with these mutant APC proteins in tumor tissues but was able to be coprecipitated with glutathione S-transferase-fused APC protein containing a beta-catenin binding domain. These results suggest that the absence of wild type APC protein affects the subcellular localization and expression levels of beta-catenin in human tissues.

Adenomatous Polyposis Coli↗
PubMed1996

p53 mutations in the non-neoplastic mucosa of the human stomach showing intestinal metaplasia.

In order to ascertain whether genetic alterations occur during the early stages of gastric carcinogenesis, abnormal accumulation of p53 protein and mutation of its gene in stomach tissue showing intestinal metaplasia were investigated using immunohistochemistry and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. Immunohistochemistry detected 19 foci showing nuclear accumulation of p53 protein in non-neoplastic gastric mucosa in a total of 756 sections (477 of which contained intestinal metaplasia) from 16 resected stomachs containing gastric adenocarcinomas. Of these 19 p53-positive foci, 17 were diagnosed histologically as incomplete-type intestinal metaplasia and 2 as pseudopyloric glands in the regenerative mucosa. Furthermore, 14 such foci were detected in 6 patients with multiple gastric cancers. No correlation between high-iron diamine (HID)-positive sulfomucin production and p53-positive glands was observed. The DNAs were extracted selectively from these p53-positive metaplastic glands and examined for p53 mutations by PCR-SSCP analysis followed by direct sequencing. In only 10 lesions could exons; 5 to 8 be investigated completely, and of these, 4 were shown to possess p53 mutations, which were on exon 5 in 3 cases and on exon 7 in 1 case. These results indicate that irreversible genetic changes had already occurred in morphologically non-neoplastic gastric mucosa with intestinal metaplasia, and are consistent with the hypothesis that intestinal metaplasia, especially the incomplete type, may contain precursor lesions of gastric cancer.

Base Sequence↗
PubMed1996

Risk factors for lymph node metastasis from intramucosal gastric carcinoma.

BACKGROUND: Although regional lymph node metastasis from intramucosal early gastric carcinoma (EGC) is rare, it is very important to clarify the characteristics of patients having lymph nodal metastases in order to determine appropriate therapy. METHODS: The authors investigated 1196 patients with solitary intramucosal EGC who underwent resection at the National Cancer Center Hospital in Tokyo, with special reference to lymph node metastases. Eight clinicopathologic factors (age, sex, tumor: size, location, macroscopic type, histologic type, histologic ulceration of the tumor, and lymphatic vessel invasion) were investigated by univariate and multivariate analyses for their possible relationship to lymph node metastasis. RESULTS: Lymph node metastases were found in 43 patients (3.5%). Univariate analysis revealed that younger age (< 57 years), macroscopic depressed type, larger tumor size (> or= 30 mm), undifferentiated histologic type, histologic ulceration of the carcinoma, and lymphatic vessel invasion had a significant association with regional lymph node metastasis. Multivariate analysis revealed that lymphatic vessel invasion, histologic ulceration of the tumor, and larger size (> or = 30 mm) were independent risk factors for regional lymph node metastasis. The incidence of lymph node metastasis from intramucosal EGC negative for these 3 risk factors was only 0.36% (1 in 277 patients). CONCLUSIONS: Lymphadenectomy is unnecessary for patients with small intramucosal EGC with neither histologic ulceration of the tumor nor lymphatic vessel invasion because the incidence of regional lymph node metastasis is extremely low in those patients. The therapeutic options for such patients would be local resection or endoscopic resection.

Age Factors↗
PubMed1996

Simultaneous expression of cadherin-11 in signet-ring cell carcinoma and stromal cells of diffuse-type gastric cancer.

We examined the expression of cadherin-11, a type II cadherin, in normal human tissues, cell lines and gastric cancer surgical specimens. Cadherin-11 was expressed widely in adult tissues, except the liver. It was expressed in fibroblast, mesothelial cell lines, and in only two signet ring cell carcinomas out of 16 various cancer cell lines. Cadherin-11 expression was detected in both signet ring cell carcinoma cells and surrounding fibroblasts of surgical specimens by in situ hybridization. These results suggest that cadherin-11 may play a role in the formation of diffuse-type gastric cancer through cancer-stromal interactions.

Adult↗
PubMed1996

Clinical implications of microsatellite instability in colorectal cancers.

BACKGROUND: Microsatellite instability (MI) has been reported in some sporadic colon tumors and in cases of hereditary nonpolyposis colorectal cancer (HNPCC). The criteria for HNPCC have not been fully defined, and clinical criteria are used to identify as many HNPCC patients as possible. To clarify the conformity of these criteria with the identification of eligible HNPCC cases, we analyzed MI in HNPCC patients diagnosed using clinical criteria. METHODS: Genomic DNA was extracted from surgical specimens of 56 colorectal cancers, including 36 from patients diagnosed with HNPCC using the clinical criteria. We analyzed four microsatellite loci using 32P-labeled primers. RESULTS: Among HNPCC patients diagnosed using clinical criteria, patients who were positive for MI accounted for 62% of Group A (a confirmed group) and 35% of Group B (a high risk group); only 5% of randomly selected colorectal cancer patients (Group C), were positive for MI. Furthermore, MI-positive tumors were found in patients who had a tendency for tumors to involve the right side of the colon, an association with cancers in other organs, a lower incidence of p53 protein positivity, and a higher proportion of poorly differentiated cancers. CONCLUSIONS: The presence of MI, in concert with modified clinical criteria, may identify legitimate cases of HNPCC in patients who might otherwise be excluded by the minimum criteria.

Age of Onset↗
PubMed1996

Recurrent esophageal carcinoma after esophagectomy with three-field lymph node dissection.

To evaluate the effect of the extended lymphadenectomy for thoracic esophageal carcinoma, the pattern of recurrence in the 50 patients with pT3 tumors who underwent esophagectomy with cervical, mediastinal, and abdominal lymph node dissection (3-F) (group A) was compared with that of 100 patients at pT3 who underwent esophagectomy without upper mediastinal and cervical lymphadenectomy (2-F) (group B). The cumulative 5-year survival rate for 115 patients who underwent 3-F was 50.9%. Cumulative 5-year survival rates for patients in groups A and B were 36.8% and 22.0%, respectively. The survival curve for group A was significantly better than group B (P = 0.02332). Lymphatic recurrence was noted less frequently in group A (8/23) than in group B (31/49) (chi 2 = 5.1149), whereas the rate of hematogenous recurrence was similar. Extension of the field of lymph node dissection reduced the lymph node recurrence in patients with thoracic esophageal carcinoma, which may have positively affected patient survival.

Aged↗
PubMed1996

In vitro reconstituted tissue as an alternative to human respiratory tract.

The data obtained from in vitro systems utilizing human cells and tissues should form a basic part of the information necessary for risk assessment. The most important thing for such systems is, therefore, to simulate the structures and functions of cells and tissues in the native organ as closely as possible. In designing in vitro systems, there may be two approaches-one aiming at the growth of cells in a primarily two-dimensional fashion, the other allowing cells to form in vivo-mimicking three-dimensional architectures. In cultures in which the airway epithelial cells are growing in a two-dimensional fashion, some functional and structural characteristics can be developed to a considerable extent. However, there are some that cannot be developed or expressed under that condition but require a three-dimensional growth pattern. In this paper we explore the capacity of early to long-term passage airway epithelial cells (human and hamster) to resume architectures and functions existing in the native tissue in the specific environments given in vitro.

Animals↗
PubMed1996

Ultrasonic estimation of bladder weight as a measure of bladder hypertrophy in men with infravesical obstruction: a preliminary report.

The aim of the present study was to evaluate the usefulness of ultrasonic estimation of bladder weight as a measure of bladder hypertrophy using transabdominal ultrasonography in men with infravesical obstruction. Ultrasonically estimated bladder weight (UEBW) was calculated from the thickness of the bladder wall measured ultrasonically and the intravesical volume at the ultrasonic measurement, assuming a spheric bladder. There was a statistically significant correlation (r = 0.970, P <0.001) between the actual bladder weight of cadaver bladders and the UEBW. The UEBW did not change with bladder filling. The UEBW in the obstructed group (group O, 49.7 +/- 19.5 g, mean +/- SD) was significantly greater than that in the normal control group (group NC, 25.6 +/- 5.7 g; P <0.001) or the nonobstructed group (group NO, 28.4 +/- 4.2 g; P <0.001). The greatest UEBW was 34.8 g in group NC and 35.2 g in group NO, whereas 94% (45 of 48) of group O had a UEBW greater than 35.0 g. In all 5 patients with benign prostatic hyperplasia (BPH), the increased UEBW decreased to a normal control level at 3 months after treatment of BPH. This new noninvasive method may be useful in investigation of bladder hypertrophy.

Adult↗
PubMed1996

E-cadherin gene mutations in signet ring cell carcinoma of the stomach.

To clarify the significance of E-cadherin gene alterations in the development of diffuse-type adenocarcinoma of the stomach, we analyzed mutations of the E-cadherin gene using the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) method followed by direct sequencing. Twenty-two signet ring cell carcinomas of the stomach (10 intramucosal and 12 advanced cancers) were examined. Genomic DNA was extracted separately from cancerous and non-cancerous tissues and PCR-SSCP analysis was performed on exons 5 to 9 and the adjacent 30- to 40-base-pair intron sequences of the E-cadherin gene. Mobility shifts were found in 2 of the 10 intramucosal cancers. In 2 of the 12 advanced cancers, abnormalities of the E-cadherin gene were observed in intramucosal lesions as well as in deeply invaded areas. These results indicated that E-cadherin gene mutations are an early event in the development of signet ring cell carcinoma of the stomach. Direct sequencing revealed that the locations of mutations of the E-cadherin gene included the branch point sequence in the intron which is responsible for RNA splicing. Reverse transcriptase-PCR demonstrated aberrant RNA splicing in a case with a branch point mutation, suggesting that branch point mutations play an important role in functional modifications of E-cadherin in signet ring cell carcinoma of the stomach.

Adult↗
PubMed1996

Formation of focal adhesion and spreading of polarized human colon cancer cells in association with tyrosine phosphorylation of paxillin in response to phorbol ester.

Regulation of cell adhesion systems is involved in both normal development and the invasive behavior of carcinomas. We examined alterations of cell morphology and adhesion molecules in response to phorbol ester treatment of the SW1116 colon cancer cell line, which forms well-organized dome-like tubular structures in culture. 12-O-Tetradecanoylphorbol-13-acetate (TPA) induced rapid spreading of cancer-cell colonies through formation of focal adhesion and disappearance of adherens junctions. Immunologic analyses demonstrated that tyrosine-phosphorylated proteins were concentrated at focal adhesions, and that tyrosine phosphorylation of two proteins, paxillin and an unidentified 130-kd protein, was significantly increased. Tyrosine phosphorylation of paxillin was detectable within 15 min after TPA treatment, when only lamellipodia had extended from the colony, and in cells treated with blocking antibodies against integrins beta 1 and beta 5, which strongly inhibited spreading and disorganization while preserving adherens junctions. The level of paxillin phosphorylation correlated well with the degree of morphologic change induced by low-dose TPA, and the dephosphorylation occurred before reversion of morphology upon removal of TPA. These findings suggest that the TPA signal was transduced to the tyrosine phosphorylation of paxillin strongly associated with formation of focal adhesion, and that this in turn induced dysfunction of the cadherin system and caused spreading and disorganization of the tubular structure. The mechanism responsible for disruption of the cadherin system at adherens junctions was not clear, but the transition of beta-catenin into nuclei corresponded to the disappearance of its signal along areas of cell-cell contact. This SW1116 model provides a good system for studying the molecules involved in transient regulation and crosstalk between the cell-cell and cell-substratum adhesion systems, which may explain the mechanism of invasion of well-differentiated human carcinomas.

Antibodies, Monoclonal↗
PubMed1996

Loss of heterozygosity of multiple tumor suppressor genes in human gastric cancers by polymerase chain reaction.

Loss of heterozygosity (LOH) occurring on various chromosomes has been described in the majority of human tumors and its targets are believed to be tumor suppressor genes. Although allelic deletion of the p53 gene (over 60%) has been frequently observed in gastric cancer, as well as in other human malignancies, LOH of other tumor suppressor genes is still discrepant in gastric cancer. To our knowledge, simultaneous analysis of LOH using PCR in adenomatous polyposis coli (APC), deleted in colon cancer (DCC), and retinoblastoma susceptibility (Rb) genes has not yet been reported in sporadic gastric cancer. We examined 21 advanced gastric cancers (12 intestinal type and 9 diffuse type) for LOH at the APC, DCC, and Rb loci using PCR. Inclusion of these tumor suppressor genes in the allelic deletions was directly ascertained by performing PCR at polymorphic sites within the genes. LOH occurred in 30% of informative cases at APC, in 27% of informative cases at DCC, and in 30% of informative cases at Rb. Thirty-three percent of tumors informative at all loci (fully informative) lost heterozygosity at all three loci. There were no significant differences among histologic types in the prevalence of LOH at any locus and no correlations between losses involving APC, DCC, and Rb genes. These data suggest that inactivation of APC, DCC, and Rb is involved in the development and progression of some human gastric cancers regardless of histologic type.

Base Sequence↗
PubMed1996

A statistical study of the American Urological Association symptom index for benign prostatic hyperplasia in participants of mass screening program for prostatic diseases using transrectal sonography.

PURPOSE: A study was done on the prevalence of urinary symptoms in community based populations in Japan regarding the influences of aging and benign prostatic hyperplasia (BPH) as evaluated by transrectal sonography. MATERIALS AND METHODS: In 961 Japanese men 55 to 87 years old who underwent mass screening for prostatic diseases the American Urological Association symptom index scores were compared with age and ultrasonic diagnosis of the prostate. RESULTS: Moderate to severe symptoms (symptom score 8 or more) were found in 265 of our 961 samples (27.6%), while BPH was also recognized ultrasonically in 197 (20.5%). Frequencies of urinary symptoms and BPH increased significantly with age. BPH related increase in total symptom scores occurred only in select men when adjusted by age. CONCLUSIONS: The ability of the American Urological Association symptom index to characterize BPH in an individual was limited because of the lack of specificity to the disease along with the considerable influence of aging on the symptom score. Currently, transrectal sonography is the most reliable method for the definitive diagnosis of BPH.

Age Distribution↗
PubMed1996

Immunohistochemical detection of K-sam protein in stomach cancer.

The K-sam gene, originally isolated as an amplified gene from the stomach cancer cell line KATO-III, is characterized by its preferential amplification in the undifferentiated type (diffuse type) of stomach cancer and encodes one of the receptors for heparin-binding growth factors or fibroblast growth factors. The K-sam gene has been isolated by different methods and has been designated BEK, TK14, and Cek2. The receptor for keratinocyte growth factor was also found to be encoded by the same gene. To examine the expression of the K-sam protein in stomach cancer, polyclonal antibody pK1-2 was raised against the extracellular domain of the gene product. This antibody detected K-sam proteins by Western blot and flow cytometry analyses in stomach cancer cell lines KATO-III and HSC39, in which the K-sam gene is amplified and overexpressed. By immunohistochemical analysis, 20 of 38 cases of the undifferentiated type of advanced stomach cancer were K-sam positive, whereas none of 11 cases of the differentiated or intestinal type revealed K-sam staining. The K-sam product was observed predominantly in diffusely infiltrative lesions. In one autopsy case, the K-sam protein was detected only focally in the primary tumor, whereas markedly increased staining for the K-sam product was detected diffusely in the metastasized tumor in the lymph node and liver. These results suggest that K-sam overexpression is associated with the malignant phenotype of the undifferentiated type of stomach cancer, such as infiltrative growth and metastasis.

Amino Acid Sequence↗
PubMed1995

Silencing of the E-cadherin invasion-suppressor gene by CpG methylation in human carcinomas.

E-Cadherin, a cell adhesion molecule, which plays a key role in maintaining the epithelial phenotype, is regarded as an invasion-suppressor gene in light of accumulating evidence from in vitro experiments and clinical observations. In an attempt to clarify the mechanism responsible for inactivation of this gene in carcinomas, we investigated the methylation state around the promoter region by digestion of DNA with the methylation-sensitive restriction enzyme Hpa II, as CpG methylation of the promoter has been postulated to be a mechanism of transcriptional inactivation of some genes. We found that E-cadherin expression-negative carcinoma cell lines were accompanied by the hypermethylation state, whereas E-cadherin-positive cell lines were not. Furthermore, treatment of E-cadherin-negative carcinoma cells with the demethylating agent 5-azacytidine resulted in reexpression of the gene and reversion of scattered spindle-shaped cells to cells with epithelial morphology. These results suggest that hypermethylation around the promoter may be a mechanism of E-cadherin inactivation in human carcinomas and that treatment of E-cadherin-inactivated cells with a demethylating agent may cause gene expression reversion leading to epithelial morphogenesis with acquisition of the homophilic cell-cell adhesive property.

Azacitidine↗