Biomedical subjects

Toshiaki Watanabe

Publications and source records attributed to Toshiaki Watanabe.

At least 127 records · Page 7Linked to original sources

PubMedDate not supplied

Temporal subtraction of thin-section thoracic computed tomography based on a 3-dimensional nonlinear geometric warping technique.

The authors developed a computer system that automatically produces temporal subtraction images on thin-section thoracic computed tomography based on a 3-dimensional nonlinear geometric warping technique. The automated subtraction system was applied to data from 20 subjects with lung diseases. Nineteen (95%) of 20 results showed good or excellent image quality. The remaining 1 (5%) showed adequate image quality. Our preliminary computer system demonstrates the potential for a clinically useful automated subtraction system.

Humans↗

PubMedDate not supplied

Diffusion-weighted magnetic resonance imaging in pituitary abscess.

Pituitary abscess is a rare but potentially life-threatening disease. The correct preoperative diagnosis of pituitary abscess is difficult and rarely made. We present a case of pituitary abscess where diffusion-weighted magnetic resonance imaging was useful in making the preoperative diagnosis of pituitary abscess.

Adult↗

PubMedDate not supplied

Cerebral lipiodol embolism after transcatheter arterial chemoembolization of hepatocellular carcinoma.

A case of cerebral lipiodol embolism after transcatheter arterial chemoembolization (TACE) of hepatocellular carcinoma is presented. A 76-year-old man underwent TACE for advanced hepatocellular carcinoma. Immediately after chemoembolization, his level of consciousness deteriorated. Computed tomography revealed deposition of iodized oil in the cerebral cortex, basal ganglia, and thalami. Magnetic resonance imaging showed restricted diffusion within the thalami and basal ganglia. The patient's level of consciousness gradually improved, and all neurologic symptoms disappeared over 6 weeks.

Aged↗

PubMedDate not supplied

Serial diffusion-weighted magnetic resonance imaging in methanol intoxication.

We report the serial magnetic resonance imaging (MRI) findings in a case of methanol intoxication. A 50-year-old man who had accidentally ingested methanol was admitted to our institution. The patient was almost blind, and became comatose. The MRI showed bilateral putaminal lesions with restricted diffusion. The MRI, which was performed on the third day after admission, showed new lesions in the subcortical white matter. The patient's general condition improved. His visual acuity, however, did not improve.

Blindness↗

PubMedDate not supplied

Does early polypoid colorectal cancer with depression have a pathway other than adenoma-carcinoma sequence?

In the carcinogenesis of colorectal cancer, the concept of adenoma-carcinoma sequence is widely accepted. In this pathway, polypoid adenoma develops into early polypoid cancer and then progresses to advanced cancer. Alternatively, some groups insist that in the de novo pathway in which early cancers develop without preexisting adenoma, flat or depressed early cancers develop into advanced cancer. According to these two different concepts of carcinogenesis, early polypoid cancers may include two distinct types of lesions, early polypoid cancers without central depression via the adenoma-carcinoma sequence and early polypoid cancers with central depression via de novo carcinogenesis. We analyzed 45 submucosal cancer specimens histologically diagnosed as polypoid by clinicopathological features and K-ras mutation in early polypoid cancers with and without depression to clarify whether there was a difference between the two groups. No significant difference in clinicopathological features was found between the two groups. Also, a high incidence of K-ras mutation was observed in both groups. This suggests that early polypoid cancers with depression have a similar genetic background to polypoid cancers without depression, which follows the adenoma-carcinoma sequence. It is possible that whether or not the tumor has a depression does not indicate the distinct pathway of colorectal carcinogenesis.

Adenoma↗

PubMedDate not supplied

Budding as a useful determinant of the optimal treatment for T1 rectal carcinomas.

BACKGROUND/AIMS: If a locally excised specimen has poorly differentiated or undifferentiated histology, positive vascular invasion, or massive invasion to the cut end or a positive margin, additional surgery is recommended for the treatment of T1 rectal carcinoma. However, positive predictive values of these histological criteria are low. This study was undertaken to clarify more reliable risk factor(s) for lymph node metastasis in T1 rectal carcinomas. METHODOLOGY: In 58 patients with T1 rectal carcinoma undergoing local excision or radical surgery, the associations between lymph node metastasis or intrapelvic recurrence and clinicopathological features were studied using multiple regression analysis with special reference to tumor budding at the invasive front. RESULTS: Lymph node metastasis was observed in 1 of 9 patients undergoing additional bowel resection after local excision, and in 2 of 24 patients undergoing radical surgery alone. Intrapelvic extrarectal recurrence was observed in 3 of 25 patients undergoing local excision alone. Logistic regression analysis revealed that budding at the invasive front alone was significantly associated with lymph node metastasis or intrapelvic recurrence (p = 0.0484). CONCLUSIONS: Additional bowel resection with lymph node dissection should be recommended for locally excised T1 rectal carcinoma with budding at the invasive front.

Adult↗

PubMedDate not supplied

The usefulness of immunohistochemical evaluation of dihydropyrimidine dehydrogenase for rectal cancer treated with preoperative radiotherapy.

BACKGROUND/AIMS: DPD (dihydropyrimidine dehydrogenase) activity shows a correlation with 5-fluorouracil chemosensitivity. To quantify DPD activity is important for selection of chemosensitive cases of not only sporadic colorectal cancer but also rectal cancer with preoperative radiotherapy. However, it is not cost-effective. We investigated the relation between the immunohistochemical expression pattern of DPD and its activity in rectal cancer treated with radiotherapy, and compared the immunohistochemical DPD expression pattern of preradiation biopsy specimens with that of resected tissues. METHODOLOGY: DPD expression pattern of preradiation biopsy specimens were compared with that of resected tissues. Eighteen colorectal cancer tissue samples were obtained after surgery from October 2000 to January 2001. DPD activity was quantified by sandwich enzyme-linked immunosorbent assay. The streptoavidin-biotin peroxidase complex technique was used for the immunohistochemical expression pattern. RESULTS: DPD was stained in the cytoplasm of cancer cells. There was a significant correlation between the immunohistochemical expression pattern of DPD and its activity in tumor tissue treated with or without radiotherapy. The immunohistochemical expression pattern of preradiation biopsy specimens was almost the same as that of resected tissues. CONCLUSIONS: The immunohistochemical expression pattern of DPD correlated with its activity in tumor tissue treated with preoperative radiotherapy. Immunohistochemical evaluation is considered to be an effective method of predicting the sensitivity to 5-fluorouracil of rectal cancer treated with preoperative radiotherapy.

Antibodies, Monoclonal↗

PubMedDate not supplied

Sporadic colorectal cancer in elderly people.

BACKGROUND/AIMS: The mechanism of the development of cancer in old age is not well understood in various cancers, especially colorectal cancer. Colorectal cancer in elderly patients often shows a high frequency of proximal colon cancer. Microsatellite instability cancers are often found in the proximal colon and show a lower incidence of p53 abnormality. While the aberrant expression of p53 is more frequent in the distal colon. To investigate the carcinogenesis of colorectal cancer in elderly patients, we studied the genetic background of these patients regarding microsatellite instability and the aberrant expression of p53. METHODOLOGY: In the present study, we examined the clinicopathological features and the frequency of p53 abnormality in elderly patients compared to younger patients, and the frequency of microsatellite instability in elderly patients. In microsatellite instability cancer, immunoreactivity of hMSH2 and hMLH1 were also examined. RESULTS: Colorectal cancer in elderly patients is associated with proximal location of the cancer (p = 0.008). Microsatellite instability was observed in only 1 case (2.8%). The immunoreactivity of hMLH1 showed negative staining in malignant glands. The frequency of aberrant expression of p53 showed no significant difference between two groups. CONCLUSIONS: We found colorectal cancer more frequently in proximal colon in elderly patients than in younger patients, and microsatellite instability frequency in elderly patients (2.8%) was lower than reported microsatellite instability frequency in sporadic colorectal cancer patients. Moreover, the frequency of aberrant expression of p53 did not differ between the two groups. In the present study, microsatellite instability appeared to be less important for the carcinogenesis of colorectal cancer in elderly patients as compared to younger patients.

Adaptor Proteins, Signal Transducing↗

PubMedDate not supplied

Reduced p16 expression correlates with lymphatic invasion in colorectal cancers.

BACKGROUND/AIMS: P16, the tumor suppressor gene, plays a crucial role in the most important regulatory pathway involved in the G1/S transition, but its role in gastrointestinal neoplasia remains unclear. METHODOLOGY: To evaluate the possible p16 role in the development of colonic neoplasms, the authors studied p16 immunohistochemical expression of 84 lesions of colorectal cancers, 6 lesions of hyperplastic polyps, 59 lesions of adenomas and 8 lesions of carcinoma in adenoma. Immunohistochemical staining was processed by streptavidin biotin technique. The degree of expression pattern was classified into four types: absent, scattered, or nested, diffuse. Also, the correlation between immunohistochemical expression pattern and clinicopathological features was evaluated. RESULTS: Compared with normal colonic mucosa, in which virtually no p16 expression was observed, p16 was overexpressed in hyperplastic polyps (33%:2/6) adenomas (46%:27/59), carcinoma in adenoma (88%:7/8) and in adenocarcinomas (98%:82/84). In colorectal cancers, when divided into positive (diffuse or nested) and negative (absent or scattered) subgroups, the negative group showed a higher ratio of lymphatic infiltration (p = 0.04), a higher ratio of deeper invasion (p < 0.01) and a higher ratio showing histology of mucinous carcinoma or poorly differentiated adenocarcinoma (p < 0.01). CONCLUSIONS: In colorectal cancers, a significant correlation of reduced p16 expression and lymphatic invasion was observed, which suggested and colorectal cancers with reduced p16 expression have more aggressive potential of lymphatic infiltration. Also a significant correlation between the overexpression of p16 and tumor progression was demonstrated.

Adenocarcinoma↗

PubMedDate not supplied

The Immunohistochemical expression of endothelial cell differentiation gene-2 receptor in human colorectal adenomas.

BACKGROUND/AIMS: The EDG-2 (endothelial cell differentiation gene-2) has been characterized as one of the high-affinity receptors of lysophosphatidic acid: an extracellular lipid mediator which can induce tumor progression. Recent studies have revealed that EDG-2 plays an important role in various pathological events including cell proliferation and tumor development. The investigation of EDG-2 is thus considered important for eliciting the mechanism of tumorigenesis. However, in colorectal tissue, the clinical significance of EDG-2 expression remains unclear. In the current study, we examined the immunohistochemical expression of EDG-2 in colorectal mucosa and adenoma, and clarified its relation with the clinicopathological features. METHODOLOGY: One hundred and sixty-one colorectal polyps were resected endoscopically or surgically at our institute from 2000 to 2001. According to the degree of dysplasia, adenomas were grouped into two categories: low-grade (mild or moderate dysplasia) and high-grade (severe dysplasia or carcinoma in situ). We investigated EDG-2 expression by immunohistochemistry. RESULTS: EDG-2 was expressed almost exclusively in the cytoplasm in colorectal normal mucosa and adenoma. EDG-2 expression in normal mucosa and adenoma was 8% and 76%, respectively. EDG-2 expression was increased in low-grade adenoma compared with that in normal mucosa (P < 0.001). EDG-2 expression was significantly greater in adenomas with larger diameters (P < 0.001). CONCLUSIONS: We demonstrated that EDG-2 expression was increased in the early stage of adenoma. A significant correlation between EDG-2 expression and the size of the adenomas suggests that EDG-2 may play an important role in the growth of these adenomas.

Adenocarcinoma↗

PubMedDate not supplied

Colon cancer complicated by vascular and intestinal anomaly.

We present a case of colon cancer in a patient with an anomalous mesenteric artery, a middle mesenteric artery, associated with intestinal nonrotation. At surgery for such a rare case, an exact grasp of the feeding artery, the draining vein, and the lymphatic flow of the tumor is necessary to perform appropriate bowel resection and oncological nodal dissection. Selective angiography and preoperative endoscopic submucosal injection of India ink near the tumor were thought to be essential for surgical decision-making.

Colon↗

PubMedDate not supplied

Expression pattern of vascular endothelial growth factor-C in human colorectal normal mucosa and neoplastic mucosa.

BACKGROUND/AIMS: Vascular endothelial growth factor-C (VEGF-C) is a potent growth factor stimulating lymphangiogenesis. METHODOLOGY: We examined the expression of VEGF-C immunohistochemically in neoplastic as well as normal mucosa of colorectal tissues, and evaluated the significance of VEGF-C in colorectal carcinogenesis and as a marker to predict the outcome of colorectal cancer. RESULTS: VEGF-C was strongly stained in 70/79 adenomas (89%), but the staining was focal in all cases, and the expression pattern in adenomas was not significantly related to either dysplasia or size of the adenoma. In the 8/8 intramucosal carcinomas within adenomas, both the carcinomatous and adenomatous lesions were stained focally, but in 6 cases (75%), the VEGF-C-positive area was larger in the carcinomatous lesion than in the adenomatous lesion. In most invasive adenocarcinomas, VEGF-C was clearly stained (83/85; 98%), with both a focal (40%) and diffuse (60%) staining pattern. In invasive carcinomas, the expression of VEGF-C was significantly correlated with lymphatic involvement, lymph node metastasis and tumor size, but not with venous involvement or liver metastasis. Survival rate tended to be lower in the high VEGF-C group than in the low group, although statistical significance was not observed. CONCLUSIONS: These results suggest that VEGF-C plays a positive role in lymphatic spread in colorectal carcinomas.

Adenocarcinoma↗

PubMedDate not supplied

Expression of DNA repair protein: MYH, NTH1, and MTH1 in colorectal cancer.

BACKGROUND/AIMS: Oxidative stress is one of the causative agents of carcinogenesis. The DNA repair protein: MYH, NTH1 and MTH1 eliminate the oxidative DNA damage. In various tumors, overexpression of MTH1 has been reported. This is the first report demonstrating the expression of those proteins in colorectal cancer. METHODOLOGY: We investigated the expression of MYH, NTH1 and MTH1 by immunohistochemical typing methods in colorectal cancers obtained from consecutive patients undergoing surgery at the University of Tokyo hospital. RESULTS: High MYH immunoreactivity was detected in 57% of cases (46/81), which showed a significant correlation with the depth of tumor (p=0.04). Cytoplasmic expression of NTH1 was detected in 35% of cases (28/81), which showed a significant correlation with lymph node metastasis (p=0.001), histological grade according to the Dukes' Classification (p=0.005), and disease-free survival (p=0.04). High MTH1 immunoreactivity was detected in 84% of cases (68/81), which showed a significant correlation with tumor location (p=0.04). CONCLUSIONS: The expression pattern of DNA repair protein for oxidative DNA damage showed a significant correlation with aggressive features of colorectal cancer such as the depth of tumor, and lymph node metastasis, as well as with Dukes' classification and disease-free survival.

Colorectal Neoplasms↗

PubMedDate not supplied

Pathological changes of advanced lower-rectal cancer by preoperative radiotherapy.

BACKGROUND/AIMS: In the treatment of lower rectal cancer, we examined the pathological effects of preoperative radiotherapy on intramural spread of tumor and risk factors for local recurrence, including tumor deposit, budding growth of primary tumors, and micrometastasis to lymph nodes. METHODOLOGY: Ninety-four patients who underwent surgery for lower rectal cancer were selected. Forty-seven patients received preoperative radiotherapy, at a total dose of 50 Gy [Rad(+) group], whereas 47 did not [Rad(-) group]. Intramural spread was evaluated between the Rad(+) and Rad(-) groups. For analysis of tumor deposit, budding, and micrometastasis, 25 stage-matched patients were selected in both groups. RESULTS: Intramural spread was significantly less in the Rad(+) group, compared with the Rad(-) group. The Rad(+) group showed a significant decrease in tumor deposit, budding, and micrometastasis, compared with the Rad(-) group. In patients having overt lymph node metastases or not, the tumor deposit and budding were significantly higher in patients having overt metastases, compared with those not having them, in the Rad(-) group, whereas there was no significant difference in the Rad(+) group. CONCLUSIONS: Intramural spread and tumor deposit, budding, and micrometastasis were significantly decreased in the Rad(+) group, compared with the Rad(-) group. These results suggested effects of preoperative radiotherapy for sphincter preservation, as well as for decreasing the local recurrence rate.

Adult↗

PubMedDate not supplied

What types of colorectal cancer overexpress the MAGE protein?

BACKGROUND/AIMS: Tumor-specific antigens such as Melanoma-associated antigens could be attractive targets for immunotherapy. It will be a great help for cancer immunotherapy to distinguish what types of tumor expresses tumor-specific antigen. METHODOLOGY: We investigated the expression pattern of MAGE-A1 by immunohistochemical typing methods in human colorectal cancers obtained from consecutive patients undergoing surgical treatment at the hospital of the University of Tokyo. RESULTS: In 35 of 89 cases (39%), MAGE-A1 positive immunoreactivity was detected in the malignant glands. MAGE-A1 positive immunoreactivity was significantly higher among the patients under the age of 70 than among those 70 years of age and older (p=0.04). Among the patients under the age of 70, the tumors located in the distal colon (descending colon, sigmoid colon and rectum) showed significantly more positive MAGE-A1 immunoreactivity than those in the proximal colon (cecum, ascending colon and transverse colon) (p=0.04). The expression pattern of MAGE-A1 was not associated with gender, size, depth, histological type, vessel invasion, lymphatic invasion, lymph nodal invasion or stage of disease. CONCLUSIONS: Relatively better results can be expected with MAGE-A1 immunotherapy among patients with distal colon cancer under the age of 70.

Age Factors↗

PubMedDate not supplied

Evaluating the combination of molecular prognostic factors in tumor radiosensitivity in rectal cancer.

BACKGROUND/AIMS: The local recurrence ratio following surgery alone is higher in patients with rectal cancer than in those with colon cancer. Preoperative radiotherapy reduces the rate of local recurrence and improves the chances of survival in patients with resectable advanced rectal carcinoma. Identification of predictive indicators of radiosensitivity is useful in selecting patients best suited for preoperative radiotherapy and thus helps to avoid unnecessary preoperative treatment. We investigated whether the combination of Ku, p53, p21, and p16 predicted tumor radiosensitivity. METHODOLOGY: We studied 96 cases with advanced rectal carcinoma. In preradiation biopsy specimens of tumor samples, all immunoreactive nuclei of cells stained positive for Ku, p53, p21, and p16 were evaluated by immunohistochemistry. The expression of p53, p21 and p16 in more than 5% of tumor cells were defined as positive, whereas both Ku70 and Ku86 protein in more than 70% of such cells were defined as Ku positive. The expression patterns of Ku, p53, p21, and p16 were examined for association with tumor radiosensitivity, which was determined according to the criteria of histopathologic assessment of radiotherapy effects. RESULTS: Univariate analysis showed a correlation between the expression patterns of Ku, p53, p21, and p16 and tumor radiosensitivity, while multivariate analysis showed that the expression pattern of Ku and p16 significantly correlated with tumor radiosensitivity. The combination of Ku and p16, or Ku, p53, p21 and p16 was therefore a good predictive marker for tumor radiosensitivity. CONCLUSIONS: These findings tend to support the hypothesis that the combination of Ku, p53, p21, and p16 expression after radiotherapy can act as a marker for radiosensitivity. Further investigation is needed, as the number of cases in this study was limited.

Adult↗

PubMedDate not supplied

Expression pattern of telomerase reverse transcriptase in rectal carcinoma predicts tumor radiosensitivity, local recurrence and disease-free survival.

BACKGROUND/AIMS: Predictive indicators of radiosensitivity in rectal cancer are required in order to avoid unnecessary preoperative radiotherapy. Telomeres are specialized structures at the ends of chromosomes that protect against that such as irradiation. Lower telomerase activity has been reported to be related to radiosensitivity in vitro or vivo. The aim of this study was to examine the possible role of telomerase reverse transcriptase expression, which is correlated to telomerase activity, in determining tumor radiosensitivity, local recurrence, and disease-free survival in patients with rectal carcinomas. METHODOLOGY: We studied 96 cases with advanced rectal carcinoma. In preradiation biopsy specimens of tumor samples, the number of cells stained positive for telomerase reverse transcriptase protein was evaluated by immunohistochemistry. RESULTS: The expression pattern of telomerase reverse transcriptase protein correlated with tumor radiosensitivity (P=0.0007). All tumors that had a high percentage of telomerase reverse transcriptase positive cells were radioresistant. High telomerase reverse transcriptase expression pattern is a predictive marker for high local recurrence or poor survival in patients with rectal cancer (P=0.011, P=0.0005). Telomerase reverse transcriptase expression and histopathological grade were significant prognostic variables for disease-free survival in the multivariate analysis (P=0.0003, P=0.0091). CONCLUSIONS: Telomerase reverse transcriptase raises the predictive possibility of tumor radiosensitivity in rectal cancer. Telomerase reverse transcriptase might be a useful parameter for patient selection for preoperative radiotherapy in rectal carcinoma.

Adenocarcinoma↗

PubMedDate not supplied

Prognostic significance of Ku70 protein expression in patients with advanced colorectal cancer.

BACKGROUND/AIMS: Ku protein stimulates DNA repair and signals the damage/stress responses, which may affect apoptosis and cell proliferation. The expression of Ku70 has been reported to be related to cell proliferation in a human gastric cancer cell line. However, in colorectal carcinoma, the clinical significance of Ku70 expression remains unclear. We examined the expression pattern of Ku70 in sporadic colorectal cancer and its relation to clinicopathological parameters and survival. METHODOLOGY: We studied 101 consecutive cases of advanced colorectal carcinoma. In resected specimens, the number of cells stained positive for Ku70 protein was evaluated by immunohistochemistry. RESULTS: The percentage of cells expressing Ku70 in different tumors ranged from 4.2-99.7%. The elevated Ku70 expression group comprised 52 of 101 cases (52%). No significant correlation was seen between Ku expression pattern and the clinical parameters except depth of invasion. pTNM stage, histopathological grade and Ku70 were significant variables for prognosis of survival in the multivariate analysis. CONCLUSIONS: This is the first report correlating reduced survival with elevated expression of Ku protein in colorectal adenocarcinoma. Ku may be a new prognostic marker useful for selecting adjuvant treatment strategies.

Adenocarcinoma↗