Biomedical subjects

Y Maehara

Publications and source records attributed to Y Maehara.

At least 19 recordsLinked to original sources

PubMed2001

The instability within: problems in current analyses of microsatellite instability.

Microsatellite instability is regarded as one of the phenotypes of defective DNA mismatch repair and, consequently, as a marker of high risk for cancer. Despite numerous studies, the reported rates for positive microsatellite instability differ widely in each human malignancy. These discrepancies may relate to problems in the methods used. To establish a methodology for an accurate microsatellite instability analysis, technical requirements for a precise assay and biological conditions required for positive microsatellite instability were discussed. First, to describe microsatellite changes in detail, a sensitive detection system with linear detection characteristics and electrophoresis with standardised migration and minimised migration errors are considered to be necessary. Therefore, systems using fluorescent labelling and laser scanning are recommended. For reproducible polymerase chain reactions, it is essential to control the terminal deoxynucleotidyl transferase activity in Taq polymerase. Second, as a biological condition for positive microsatellite instability, feasible selection and combination of microsatellite markers, mutations in specific DNA mismatch repair genes and existence of monoclonal populations enriched sufficiently in a sample are essential. Finally, one possible diagnostic criterion for positive microsatellite instability is proposed, that is the existence of one of the patterns shown in the panel (see Fig. 6) at one or more loci in a set of more than five microsatellite markers.

DNA Repair↗

PubMed2001

Prognostic significance of natural killer cell activity in patients with gastric carcinoma: a multivariate analysis.

OBJECTIVE: Natural cytotoxicity, mediated by natural killer (NK) cells, has been believed to play an important role in inhibiting experimental tumor metastasis, and diminished NK cell activities leads to a high incidence of tumor occurrence. Despite convincing evidence from experimental studies, the role of NK cells in the immunological surveillance against cancer in human is poorly defined. METHODS: The present study was based on a retrospective analysis of data on 156 patients with gastric cancer, who were surgically treated in the Department of Surgery II, Kyushu University Hospital from 1993 to 1996. All patients were examined for NK cell activity based on a peripheral blood sampling done preoperatively. RESULTS: Significant association between NK cell activity and clinicopathological parameters including tumor size, lymphatic involvement, vascular involvement, and lymph node metastases was evident. When comparing the two groups according to NK cell activity, tumors with low NK cell activity tend to have lymphatic involvement. The 5-yr survival rates were 94.6% and 72.3% for those with NK cell activity > 25% lysis and < or = 25% lysis, respectively, the value being statistically significant (p < 0.05). The independent risk factors for prognosis examined by logistic regression analysis were lymphatic involvement. NK cell activity, depth of tumor invasion, and lymph node dissection. CONCLUSIONS: These current data showed that NK cell activity may be related to tumor volume and dissemination. Measurement of preoperative NK cell activity may be pertinent for the prognosis of patients with gastric cancer and for follow-up clinical management.

Cytotoxicity, Immunologic↗

PubMed2001

Overexpression of vascular endothelial growth factor C is related to lymphogenous metastasis in early gastric carcinoma.

Vascular endothelial growth factor C (VEGF-C) is considered to be potentially lymphangiogenic and can selectively induce hyperplasia of the lymphatic vasculature. In this study, we clarified the clinicopathological features of early gastric carcinoma (EGC) that has metastasized to the lymph nodes, as well as the correlation between lymphogenous metastases in EGC and the expression of VEGF-C and VEGF. We selected 35 cases of lymph node metastasis-positive [n(+)] EGC and 70 cases of lymph node metastasis-negative [n(-)] EGC for the present study. The expression of VEGF and VEGF-C was investigated with immunohistochemical staining using monoclonal antibodies against VEGF and VEGF-C. Clinicopathologically, there were significant differences in median size (4.1 +/- 2.4 vs. 2.4 +/- 1.7 cm), lymphatic invasion (54 vs. 4%) and venous invasion (23 vs. 3%) between n(+) EGC and n(-) EGC. Immunohistochemically, the incidence of positive expression of VEGF-C in lymphatic invasion-positive EGC (36%) was significantly higher than that in lymphatic invasion-negative EGC (14%). The incidence of positive expression of VEGF-C in n(+) or venous invasion-positive EGC tended to be higher than that in n(-) or venous invasion-negative EGC. In conclusion, lymphatic invasion was significantly increased in VEGF-C-positive EGC.

Aged↗

PubMed2000

Diminished expression of ING1 mRNA and the correlation with p53 expression in breast cancers.

p33(ING1) is a novel candidate tumor suppressor and its overexpression induces growth arrest or apoptosis in different cell lines. These functions of p33(ING1) depend largely on the activity of p53, and p53-dependent activation of the transcription from the p21/WAF1 promoter also requires p33(ING1). We examined the expression of ING1 mRNA in breast cancer cell lines and clinical breast cancer tissues, using quantitative RT-PCR and real time TaqMan technology. In breast cancer cell lines, ING1 mRNA was expressed at almost the same level. However, in a comparison between the cancer and matched normal tissues, a significant decrease in ING1 mRNA expression was found in 17 of 24 (70.8%) breast cancer tissues. We also examined the correlation between ING1 mRNA expression and p53 expression. There was a significant decrease of ING1 mRNA in nine of 15 tumors negative for p53 immunostaining, most of which were considered to have wild type p53. In these tumors, p53 may not function in case of a decreased expression of p33(ING1), and the lack of cell cycle regulation may correlate with the carcinogenesis and tumor progression.

Breast Neoplasms↗

PubMed2000

A phase II trial of a new 5-fluorouracil derivative, BOF-A2 (Emitefur), for patients with advanced gastric cancer.

The antineoplastic effects of BOF-A2 (Emitefur), a 5-fluorouracil (5-FU) derivative, in capsule form were assessed in patients with advanced gastric cancer, in a multicenter late phase II study and at 11 different hospitals. The patients were scheduled to receive a minimum of two courses of BOF-A2 orally, with each course of BOF-A2 consisting of 200 mg twice daily for 2 weeks followed by a withdrawal period of 2 weeks. Of the 24 patients entered into the study, the clinical response was able to be evaluated in 21 cases and the toxicity was determined in 23 cases. Eleven (45.8%) patients had been treated previously with other anticancer drugs. There was a 38.1% (8/21) response rate (95% confidence interval 17.3-58.9) with 1 (4.8%) complete response (CR) and 7 (33.3%) partial responses (PR), and these responses continued for over 4 months. In particular, the response rate for the primary lesion was 33.3% (3/9). No change (NC) in the disease was observed in 5 (23.8%) patients, and in 8 (38.1%) the disease progressed (PD). At the time of analysis, the median survival of the responders was 13 months, while that of the NC group was 7 months and that of the PD group was 2 months. The major adverse events consisted of gastrointestinal symptoms, myelosuppression, and skin symptoms, while toxicities of grade 3 or more occurred in 26.1% (6/23). These toxicities all resolved within 1-37 days after discontinuing the drug treatment. Based on the above findings, BOF-A2 is considered to be a promising anticancer drug for patients with advanced gastric cancer.

Administration, Oral↗

PubMed2000

Differential growth inhibition by 5-fluorouracil in human colorectal carcinoma cell lines.

The effects of 5-fluorouracil (5-FU) on cell growth were investigated using a primary culture of human fibroblasts, MRC-5, and three established human colon cancer cell lines, DLD-1, LoVo and SW620. Detailed flow cytometric analyses revealed differential growth inhibition among these cell lines including three modes of cell growth modulation: (a) loss or accumulation of S phase cells; (b) G2/M block; and (c) G1-S arrest. From analyses on the amount of 5-FU incorporated into cellular RNA and the activity of thymidylate synthase (TS), suppression of TS and depletion of dTTP, a possible consequence of the former, was considered to be the major action of 5-FU in these cells. Differences in the cellular responses to the nucleotide pool imbalance appeared to make the cell growth modulation diverse. Loss of S phase cells and G1-S phase arrest were evident in p53 wild-type cells, MRC-5 and LoVo. Cells proficient in DNA mismatch repair, SW620 and MRC-5, showed marked modulations in S-G2/M progression. These findings suggest that multiple factors, including p53 and DNA mismatch repair, participate in diverse cell growth modulations in cells treated with 5-FU. Cellular resistance to 5-FU correlated well with a loss of modulations in S-G2/M progression, rather than with a defect of G1-S arrest, which suggests the significance of DNA mismatch repair as a factor affecting the sensitivity of cells to 5-FU.

Antimetabolites, Antineoplastic↗

PubMed2000

Postoperative outcome and sites of recurrence in patients following curative resection of gastric cancer.

BACKGROUND: Recurrence occurs in a variety of forms and in different organs after 'curative resection' of gastric cancer. This study investigated the postoperative prognosis for each type of recurrence. METHODS: From 1969 to 1988, 939 patients with gastric cancer underwent curative resection; data on 130 of 207 patients who died with recurrence were analysed. Attention was focused on the site of recurrence and the postoperative outcome. RESULTS: Haematogenous recurrence was evident in 54 per cent (70 of 130 patients), peritoneal recurrence in 43 per cent (56 of 130), lymph node recurrence in 12 per cent (16 of 130) and local recurrence in 22 per cent (29 of 130). Thirty-three patients (25 per cent) had recurrences at multiple sites. Peritoneal and local recurrences were related to infiltrative growth, in contrast to haematogenous and lymphatic recurrences. There were no statistical differences in survival time among each type of recurrence and survival was not related to the number of sites of recurrence. Survival did not depend on factors of sex, age, tumour location, tumour size, depth of invasion, tissue differentiation, histological growth pattern, lymphatic and vascular involvement, lymph node metastasis and extent of lymph node dissection. CONCLUSION: The clinicopathological characteristics of gastric cancer determine the type of recurrence, although the clinical outcome is the same for each type of tumour and is not related to the number of sites of recurrence.

Humans↗

PubMed2000

Changes in E-cadherin associated with cytoplasmic molecules in well and poorly differentiated endometrial cancer.

E-cadherin function is thought to be impaired in epithelial cancer. To investigate the alterations in E-cadherin associated with cytoplasmic molecules including alpha-catenin, beta-catenin, gamma-catenin, p120CAS, and IQGAP1 in various endometrial cancers with different degree of differentiation, we examined the localization and expression of E-cadherin and cytoplasmic molecules in 30 cases of both well and poorly differentiated endometrioid adenocarcinomas, using immunofluorescence and immunoblotting techniques. E-cadherin and cytoplasmic molecules demonstrated linear staining at the cell boundaries in normal endometrium. In all 20 cases with well differentiated adenocarcinomas, alpha-catenin and IQGAP1 disappeared from the cell adhesive sites, but other cytoplasmic molecules were co-localized with E-cadherin along the cell boundaries. In all 10 cases with poorly differentiated adenocarcinomas, E-cadherin and cytoplasmic molecules accumulated as large aggregates along cell adhesive sites, and the localization of IQGAP1 differed from those of other cytoplasmic molecules. The expression of these molecules in all 20 cases with well differentiated adenocarcinomas decreased or was lost in Triton-insoluble fraction, in comparison with the findings for all cases with normal endometrium or poorly differentiated adenocarcinomas. These results suggested that each alteration in E-cadherin associated with cytoplasmic molecules may play a different role in E-cadherin dysfunction between well and poorly differentiated adenocarcinomas.

Adenocarcinoma↗

PubMed2000

Vascular endothelial growth factor-C (VEGF-C) expression in human colorectal cancer tissues.

Vascular endothelial growth factor-C (VEGF-C) functions specifically to induce lymphangiogenesis. We examined the relationship between expression of VEGF-C and clinicopathological features in patients with colorectal cancer. The expression of VEGF-C in the 99 primary tumours and 18 metastatic lymph nodes from colorectal cancer patients was examined immunohistochemically. To verify VEGF-C mRNA expression, reverse transcriptase-polymerase chain reaction (RT-PCR) was carried out. The expression of VEGF-C correlated with lymphatic involvement, lymph nodes metastasis, and depth of invasion. On the other hand, correlations were nil with regard to gender of the patients, histologic type, venous involvement, and liver metastasis. The expression of VEGF-C in metastatic lymph nodes was fairly consistent with this expression in the primary tumour. Survival time was shorter for VEGF-C positive groups than for VEGF-C negative ones, but with no statistically significant difference. RT-PCR findings revealed that the expression of VEGF-C mRNA correlated mostly with that of VEGF-C protein expression. VEGF-C may play an important role in lymphatic spread of colorectal cancer.

Adolescent↗

PubMed2000

Time trends of surgical treatment and the prognosis for Japanese patients with gastric cancer.

The incidence of gastric cancer is much higher in Japan than in other countries even though diagnostics and treatments of such patients have improved. The objective of this study was to present an overview of the past, present and future of surgical treatment for our patients with gastric cancer. We analysed data on 2152 Japanese men and women with gastric cancer who underwent surgical resection from 1965 to 1995 at Kyushu University in Fukuoka, Japan, based on a univariate and the multivariate analysis. We focused on time trends of surgical treatment and the postoperative outcome. Over the years, there have been favourable changes in the numbers of patients with early gastric cancer. In all cases of gastric cancer, the rate of 18% in the first six year period (group 1) was 57% in the last 5 year period (group 6). Size of the tumour was smaller, well-differentiated tumour tissue was more common, and lymphatic involvement was less frequent. Lymph node metastasis, liver metastasis and peritoneal dissemination all decreased. Extensive lymph node dissection was more frequently done and the rate of curative resection (curability A and B) increased. With increases in identifying the early stage of cancer and better perioperative care, mortality rates 30 days after the surgery greatly decreased. Multivariate analysis revealed that the 10 factors of depth of invasion, lymph node metastasis, lymph node dissection, tumour size, liver metastasis, peritoneal dissemination, lymphatic invasion, vascular invasion, lesion in the whole stomach and lesion in the middle stomach were independent factors for determining the prognosis. Detection of the tumour in an early stage, standardized surgical treatment, including routine lymph node dissection, close follow-up schedules and better perioperative management are expected to increase survival time for patients with this malignancy.

Female↗

PubMed2000

Significance of small distal adenoma for detection of proximal neoplasms in the colorectum.

BACKGROUND: The significance of the small distal tubular adenoma detected by sigmoidoscopy as a predictor of proximal neoplasm remains controversial. The aim of this study was to examine the prevalence of proximal neoplasms in patients with and without distal neoplasms. METHODS: This is a retrospective study of 3131 asymptomatic middle-aged men who underwent total colonoscopy. For 812 men with colorectal neoplasms characteristics of the identified neoplasms were determined. RESULTS: The prevalence of proximal neoplasms in patients with small distal tubular adenoma was 20% (92 of 461), whereas the prevalence of proximal neoplasms in patients without distal neoplasms was 11.5% (301 of 2620). The prevalence of advanced proximal neoplasms in patients with small distal tubular adenoma and without distal neoplasm was 1.3% and 0.8%, respectively. In the 29 patients with advanced proximal neoplasms, only 6 (21%) had a small distal tubular adenoma. CONCLUSIONS: The presence of small distal tubular adenomas may provide a clue to the presence of small proximal tubular adenomas. However, the majority of advanced proximal neoplasms (79%) do not have a synchronous small distal tubular adenoma. (Gastrointest Endosc 2000;52:358-61).

Adenoma↗

PubMed2000

Vascular invasion and potential for tumor angiogenesis and metastasis in gastric carcinoma.

BACKGROUND: Hematogenous metastasis occurs when cancer cells released from the primary site enter blood vessels and are transported to distant organs, where they attach and proliferate. Angiogenesis is essential for tumor growth and metastasis and depends on the production of angiogenic factors by tumor cells. METHODS: We analyzed data on 1184 Japanese adult men and women with gastric cancer with respect to the relation between vascular invasion and the potential for tumor angiogenesis and metastasis. All these patients were treated from 1976 to 1995 in the Department of Surgery II, Kyushu University. In 300 patients, the expression of vascular endothelial growth factor (VEGF) and p53 protein in tumor tissues was examined by using an immunohistochemical staining method or Northern blotting or both. Intratumoral microvessels were stained with anti-CD31 monoclonal antibody. RESULTS: Vascular invasion was evident in 254 patients (21.5%), and in these patients lymphatic invasion was more frequent and the rate of lymph node metastasis was higher in relation to the extent of vascular invasion. The positive findings were directly related to the depth of invasion and the presence of lymph node and liver metastasis. Tumor invasive and metastatic rates increased in relation to the extent of vascular invasion. Expressions of VEGF and p53 protein were higher and microvessel density was more prominent in tumor tissues in relation to the extent of vascular invasion. A close relation between VEGF and p53 protein expressions was also noted in tumors that showed vascular invasion. The expression of VEGF is one of the independent risk factors for vascular invasion. The postoperative outcome was poorer in patients with vascular invasion in relation to the extent of vascular invasion. CONCLUSIONS: Our findings show that gastric cancers with characteristics of vascular invasion have greater intratumoral angiogenesis and that VEGF and p53 overexpression is associated with intratumoral angiogenesis and metastases to distant organs.

Adult↗

PubMed2000

Analysis of Vibrio mimicus clinical strains by arbitrarily primed polymerase chain reaction.

A total of 51 Vibrio mimicus clinical strains from different geographic locations were examined by arbitrarily primed polymerase chain reaction (AP-PCR). The primer VMH-3 divided them into 28 groups, although 18 groups consisted of a single strain at present. All groups had a common 1.0-kb amplification fragment. Most of the groups consisted of strains from same region, although two exceptional groups showed a few amplification fragments including strains from different regions. AP-PCR groups were not consistently associated with serogroups. AP-PCR is thought to be a valuable and easy method for the epidemiological study of V. mimicus.

DNA Primers↗

PubMed2000

The specific expression of three novel splice variant forms of human metalloprotease-like disintegrin-like cysteine-rich protein 2 gene inBrain tissues and gliomas.

We have previously identified 67 exons on a yeast artificial chromosome contig spanning 1.5 Mb around the multidrug resistance 1 gene region of human chromosome 7q21.1. In this study, we identified three novel cytoplasmic variants (MDC2-gamma, MDC2-delta, and MDC2-epsilon) of the human metalloprotease-like disintegrin-like cysteine-rich protein 2 (MDC2) among these exons by screening a human brain cDNA library and also by using a reverse transcription polymerase chain reaction. Genomic sequence analysis strongly supported the idea that the variations in the cytoplasmic domain were generated by alternative splicing. The expression of MDC2 variant forms in human brain tissue and gliomas was examined by reverse transcription polymerase chain reaction and RNase protection assay. MDC2-epsilon was expressed only in the cortical and hippocampal regions in human brain, but not in gliomas. In contrast, MDC2-gamma was a major form expressed in human gliomas. Specific expression of these cytoplasmic variants of MDC2 in human brain and its malignancies is discussed.

ADAM Proteins↗

PubMed2000

The role of telomerase activity in hepatocellular carcinoma.

OBJECTIVE: The aim of this study was to clarify the role of telomerase activity in hepatocellular carcinoma (HCC). METHODS: Specimens from both HCC and noncancerous liver were obtained from 39 patients with HCC using a 14-gauge biopsy needle immediately after laparotomy. Telomerase activity was determined using a telomeric repeat amplification protocol assay. The 3+ of telomerase activity in HCC was defined as a high telomerase group, and 2+ or less of HCC telomerase activity was defined as a low telomerase group. In noncancerous liver, 2+ or more of telomerase activity was defined as an increased telomerase group, and 1+ or less of telomerase activity was defined as a nonincreased telomerase group. The correlation between telomerase activity in HCC or noncancerous liver and clinicopathological factors, including prognosis, was investigated. RESULTS: Telomerase activities in HCCs were 0 in one patient, 1+ in two, 2+ in seven, and 3+ in 29 patients. The disease-free survival rate in the high telomerase group was significantly worse than that in the low telomerase group. The des-gamma-carboxy prothrombin level in a high telomerase group (median, 330 mAU/ml) was significantly higher than that in the low telomerase group (median, 150 mAU/ml). A multivariate analysis revealed that higher TNM stage, high telomerase activity in HCC, female gender, and high alpha-fetoprotein value were independent significant factors related to be early recurrence. The incidence of multicentric HCC occurrence in the increased telomerase group (53.3%) tended to be higher than that in the nonincreased telomerase group (27.3%). CONCLUSION: A high telomerase activity in HCC correlated with the potential of HCC to be more malignant, which was expressed as both a high level of des-gamma-carboxy prothrombin and an earlier recurrence after hepatectomy than that of HCC with a low telomerase activity.

Adult↗

PubMed2000

Differences between features of adenoma in the rectum versus sigmoid colon.

OBJECTIVE: Although the prevalence of cancer in the rectosigmoid is high compared with that in the more proximal colon, the features of cancer developing from an adenoma have yet to be elucidated. The aim of this study is to examine the clinicopathological relationship between cancer and adenoma in the rectosigmoid. METHODS: A total of 340 adenomas located in the rectosigmoid in 255 patients were retrospectively examined regarding such clinicopathological factors as location and the grade of dysplasia. RESULTS: The prevalence of adenoma was 102 in the rectum and 238 in the sigmoid colon, respectively, whereas the prevalence of adenoma with high-grade dysplasia was 39 in the rectum and 48 in the sigmoid colon, respectively. This prevalence of adenoma with high-grade dysplasia was thus significantly higher in the rectum than in the sigmoid colon (p < 0.02). CONCLUSIONS: These findings suggest the possibility of different types of cancer development between adenoma of the rectum and sigmoid colon.

Adenocarcinoma↗

PubMed2000

Overexpression of the heat shock protein HSP70 family and p53 protein and prognosis for patients with gastric cancer.

The cell synthesis of heat shock proteins is increased by a variety of environmental and pathophysiological stressful conditions. The 70-kD heat shock protein family (HSP70 family) which constitutively expresses hsc70 and heat-inducible hsp70 is thought to be involved in protein-protein interactions, including oncogene products. We investigated the HSP70 family expression and biological behavior of gastric cancer, and its relation to p53 overexpression. Expressions of HSP70 and p53 in 164 primary gastric tumors were determined immunohistochemically. Exploratory data were analyzed on a set of 164 primary gastric cancers, and we constructed in prognostic significance of the HSP70 expression level and the relation to p53 overexpression. Expression of HSP70 (hsc70 and hsp70) were detected in nuclei and/or cytoplasm of cancer cells. Western blotting analysis showed that hsc70 and hsp70 were both expressed in five gastric cancer cell lines. Immunohistochemically stained positive cells of HSP70 varied from 0 (very weak) to 100%, in each case. The median level of positive cell rate was 19.0%. A HSP70 expression of over 19.0% was related to the differentiated tissue type of gastric cancer, but not to other clinicopathological factors. There was no difference in survival rates in subjects with higher and lower groups of HSP70 expression. HSP70 expression was also not related to p53 overexpression in the nuclei and p53 overexpression-related poorer prognosis. Our findings show that the expression of HSP70 is not associated with tumor advance-related characteristics or with the prognosis of gastric cancer. Measurements of HSP70 expression do not appear to be a useful prognostic marker.

Adenocarcinoma↗

PubMed2000

Prognosis and surgical treatment of gastric cancer invading the pancreas.

The clinicopathologic characteristics of gastric cancer invading the pancreas have not been determined. Gastrectomy was performed in 282 patients with gastric cancer invading adjacent organs at the Department of Surgery II, Kyushu University Hospital, between 1970 and 1987, and patient data were retrospectively analyzed using univariate and multivariate analyses. Of these patients, 150 (53.2%) had tumors invading the pancreas and 132 had tumors invading adjacent organs other than the pancreas. In both groups, the undifferentiated tissue type with infiltrative growth, lymphatic involvement and lymph node metastasis was common. In cases of pancreas invasion, the extent of lymph node metastasis was more severe, vascular involvement was more frequent and the rate of concomitant liver metastasis was higher. The survival time of the patients with pancreas invasion was shorter compared to patients with cancer invading other organs, and pancreas involvement was one of the independent factors predicting a poor prognosis. With respect to surgical treatment of gastric cancer invading the pancreas, the prognosis was better for cases treated with curative surgery and pancreas resection. Of 39 patients treated with partial resection of the pancreas, the tumor had invaded only the capsule of the pancreas in 18 and the pancreas in the other 21. Pancreas-invasive gastric cancer cells are likely to advance via lymphatic and vascular routes and survival time is shorter, but curative resection can improve the survival rate, and perioperative treatment should be appropriately designed.

Aged↗