Biomedical subjects

Kotaro Shibahara

Publications and source records attributed to Kotaro Shibahara.

10 recordsLinked to original sources

PubMed2006

[A case of advanced rectal cancer responding to oral UFT and Leucovorin-based preoperative chemoradiation therapy].

We report a case of a 44-year-old male with advanced lower rectal cancer that showed a significant effect after preoperative chemoradiation therapy. Preoperative radiation and chemotherapy included whole pelvis irradiation (30 Gy in total), oral UFT (500 mg/day), and Leucovorin (75 mg/day) was administered daily for 4 weeks. Consequently, the patient underwent a total pelvic exenteration with lymph node dissection (D 3). Histopathological findings showed: invasion to peritoneum(Ai); stage IIIa with n(-); and histological grading, Grade 2. Preoperative chemoradiation therapy appears to be effective for locally advanced lower rectal cancer.

Adenocarcinoma↗

PubMed2005

[Evaluation of positive cases with peritoneal lavage cytology in gastric cancer].

Peritoneal dissemination with advanced gastric cancer is of significant problem. Peritoneal lavage cytology has been an effective method for the detection of early peritoneal dissemination since 1999. The accurate evaluation of peritoneal lavage cytology is unclear except for the same prognosis of peritoneal dissemination. We examined the clinical findings and the prognosis with positive cases in peritoneal lavage cytology. The prognosis of cases with P1CY1 or P2P3 group was poorer than in the P0CY1 or P0, CY1 group. We thus review the evaluation of peritoneal lavage cytology with gastric cancer in the Japanese and English literature. In addition, we describe the diagnosis of early peritoneal dissemination using peritoneal lavage tumor markers or molecular markers of peritoneal lavage.

Adult↗

PubMed2004

Characterization of the 5'-untranslated region of YB-1 mRNA and autoregulation of translation by YB-1 protein.

The eukaryotic Y-box binding protein YB-1 is involved in various biological processes, including DNA repair, cell proliferation and the regulation of transcription and translation. YB-1 protein is abundant and expressed ubiquitously in human cells, functioning in cell proliferation and transformation. Its concentration is thought to be highly regulated at both the levels of transcription and translation. Therefore, we investigated whether or not the 5'-UTR of YB-1 mRNA affects the translation of YB-1 protein, thus influencing expression levels. Luciferase mRNA ligated to the YB-1 mRNA 5'-UTR was used as a reporter construct. Ligation of the full-length YB-1 5'-UTR (331 bases) enhanced translation as assessed by in vitro and in vivo translation assays. Deletion constructs of the YB-1 5'-UTR also resulted in a higher efficiency of translation, especially in the region mapped to +197 to +331 from the major transcription start site. RNA gel shift assays revealed that the affinity of YB-1 for various 5'-UTR probe sequences was higher for the full-length 5'-UTR than for deleted 5'-UTR sequences. An in vitro translation assay was used to demonstrate that recombinant YB-1 protein inhibited translation of the full-length 5'-UTR of YB-1 mRNA. Thus, our findings provide evidence for the autoregulation of YB-1 mRNA translation via the 5'-UTR.

5' Untranslated Regions↗

PubMed2004

Targeted disruption of one allele of the Y-box binding protein-1 (YB-1) gene in mouse embryonic stem cells and increased sensitivity to cisplatin and mitomycin C.

The eukaryotic Y-box binding protein-1 (YB-1) functions in various biological processes, including transcriptional and translational control, DNA repair, drug resistance, and cell proliferation. To elucidate the physiological role of the YB-1 protein, we disrupted one allele of mouse YB-1 in embryonic stem (ES) cells. Northern blot analysis revealed that YB-1(+/-) ES cells with one intact allele contain approximately one-half the amount of mRNA detected in wild-type (YB-1(+/+)) cells. We further found that the protein level of YB-1(+/-) cells was reduced to approximately 50-60% compared with that of YB-1(+/+) cells. However, no apparent growth difference was found between YB-1(+/-) and YB-1(+/+) cells. YB-1(+/-) cells showed increased sensitivity to cisplatin and mitomycin C, but not to etoposide, X-ray or UV irradiation, as compared to YB-1(+/+) cells. YB-1 may have the capacity to exert a protective role against cytotoxic effects of DNA damaging agents, and may be involved in certain aspects of drug resistance.

Alleles↗

PubMed2003

Y-box binding protein expression in thyroid neoplasms: its linkage with anaplastic transformation.

Recent studies have demonstrated that Y-box binding protein (YB-1) regulates the transcription of genes linked to carcinoma progression. In this study, we investigated the expression of this protein in thyroid neoplasms to elucidate its significance. The expression of YB-1 was immunohistochemically investigated using the monoclonal antibody for various thyroid neoplasms. Normal follicles did not overexpress YB-1, and only moderate overexpression of YB-1 was observed in some follicular tumors and papillary carcinoma, especially those of a larger size. In contrast, 92.9% of anaplastic carcinoma strongly overexpressed YB-1. YB-1 immunoreactivity was seen in both cytoplasms and cell nuclei, but the former was more predominant. These findings suggest that YB-1 plays a role in regulating the transcription as well as translation of genes contributing to the anaplastic transformation of thyroid carcinoma.

Adenocarcinoma, Follicular↗

PubMed2002

Detection of disseminated cancer cells in bone marrow of gastric cancer using real time quantitative reverse transcriptase polymerase chain reaction.

Bone marrow is a prognostically relevant indicator organ for micrometastasis. In the present study, real time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect disseminated gastric cancer cells in bone marrow. We compared CEA, CK18 and CK20 expression using four gastric cancer cell lines and three normal tissue cell lines in order to select the most appropriate marker for detection of disseminated gastric cancer cell in bone marrow. CK20 proved to be the most promising marker since the expression level of normal cell lines was extremely low and about 50--100-fold differences were found between gastric carcinoma cell lines and normal tissue cell lines. We also screened bone-marrow RNA of 47 patients with gastric cancers, using this system. Among the three markers we tested, with only about CK20 could we find that 27 of 47 patients were positive. Though long-term clinical follow up studies are needed to evaluate the clinical significance of this method, real time quantitative RT-PCR is sensitive and quantitative for detection of micrometastasis in bone marrow.

Adenocarcinoma↗

PubMed2002

The role of adenoma for colorectal cancer development: differences in the distribution of adenoma with low-grade dysplasia, high-grade dysplasia, and cancer that invades the submucosa.

BACKGROUND: The purpose of this study was to elucidate the role of adenoma in the early stage of colorectal cancer development, we focused on the clinicopathologic relationship between adenoma with low-grade dysplasia (ALGD), adenoma with high-grade dysplasia (AHGD), and cancer that invades the submucosa in the colorectum. METHODS: We clinicopathologically examined a total of 553 adenomas and 58 cancers that invaded the submucosa. The tissues were excised from 479 patients who underwent total colonoscopy. RESULTS: The percentage of ALGD was 79.9% in the proximal colon, 70.5% in the distal colon, and 48.3% in the rectum, respectively. The percentages of AHGD and cancer were 14.5% and 5.6% in the proximal colon, 21.3% and 8.2% in the distal colon, and 35.4% and 16.3% in the rectum, respectively. In contrast with the distribution of ALGD, the distribution of both AHGD and cancer shifted from the proximal to the distal site, with a statistical significance (P <.01). When the distribution of adenoma was compared according to tumor size, both large- and small-sized AHGD showed a similar cancer distribution, however, both large- and small-sized ALGD showed different distributions. CONCLUSION: An important role of AHGD for cancer development in the colorectum may relate to the similar distribution between AHGD and cancer; however, the different distributions observed between ALGD, AHGD, and cancer suggested that ALGD has only a slight association with the development of cancer.

Adenoma↗

PubMed1999

Clinical significance of micrometastasis in bone marrow of patients with gastric cancer and its relation to angiogenesis.

BACKGROUND: Detection of micrometastasis is an important problem of clinical significance for a better understanding and control of tumor progression, which will improve patients' survival time.METHODS: To identify micrometastases in bone marrow, an immunocytochemical assay for epithelial cytokeratin protein was performed in 106 patients with primary gastric cancer. Also, in 40 of the 106 patients, vascular endothelial growth factor (VEGF) expression and intratumoral vessel density were examined by an immunohistochemical staining method.RESULTS: Of the 106 patients, 22 (20.8%) presented with cytokeratin-positive cells in bone marrow at the time of primary surgery. The positive findings were related to depth of invasion, peritoneal dissemination, and liver metastasis. Patients with cytokeratin-positivity in bone marrow had a higher VEGF positive rate (73%; 8/11) than did cytokeratin-negative patients (48%; 14/29). Intratumoral vessel density in VEGF-positive patients was 26.9 +/- 10.3, which was significantly higher than that in VEGF-negative patients (13.2 +/- 8.7, P < 0.05). Thus, the presence of cytokeratin-positive cells in bone marrow was closely related to angiogenesis in the primary tumor.CONCLUSIONS: Cytokeratin staining can be useful for identifying patients at high risk for metastasis. Prophylactic lymph node dissection, adjuvant chemotherapy, and antiangiogenic treatment may be necessary for patients with micrometastasis.

Journal Article↗

PubMedDate not supplied

Overexpression of cyclooxygenase-2 and tumor angiogenesis in human gastric cancer.

BACKGROUND/AIMS: Cyclooxygenase-2 (COX-2) protein is overexpressed in various cancers, including esophageal, gastric, colon, and pancreatic. To better comprehend the role of COX-2 in gastric cancer, especially with regard to angiogenesis, we investigated COX-2 and vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) in 108 patients with gastric cancer. METHODOLOGY: We used immunohistochemical analysis of formalin-fixed tissues of gastric cancer. RESULTS: Expression of COX-2 showed diffuse staining in the cytoplasm of tumor cells, however, no staining in normal epithelial cells. Of the 108 tumors examined, 71 (65%) were positive for COX-2 expression, the VEGF-positive cases numbered 43 of 108 cases (39.8%). The intensity of COX-2 expression did not correlate with any clinicopathological characteristics. The positive rate of VEGF expression in COX-2-positive cases was significantly higher than in COX-2-negative ones (47.9% vs. 24.3%, P<0.05). MVD in COX-2-positive cases was significantly higher than in COX-2-negative ones (22.0+/-7.8 vs. 18.5+/-7.5/1 mm2; P<0.05). CONCLUSIONS: Our study provides evidence that COX-2 is closely related with angiogenesis.

Adenocarcinoma↗

PubMedDate not supplied

A case of gastric hyperplastic polyp with malignant transformation.

In this paper we report a case of hyperplastic polyp with malignant transformation. The patient was followed up by annual radiographic and endoscopic examination during 9 years. The first gastroscopy revealed a semi-pedunculated polyp beneath the esophageal-cardiac junction, 1.5cm in diameter and slightly reddish with smooth surface. Histological findings showed a hyperplastic polyp. There was slight change in size, but no change in histological examination of the lesion during the follow-up. In 1996, the biopsy specimen showed an atypical epithelium and the polyp was removed by snear polypectomy. A microscopic examination revealed a well-differentiated adenocarcinoma. Immunohistochemically, p53 and Ki-67 immunostaining showed positive in the carcinoma portion of the adenocarcinoma bearing a hyperplastic polyp in the stomach.

Aged↗