Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Kou Nagasako is active.

Publication


Featured researches published by Kou Nagasako.


Gastrointestinal Endoscopy | 1995

Minute flat depressed neoplastic lesions of the colon detected by contrast chromoscopy using an indigo carmine capsule

Hideki Mitooka; Takahiro Fujimori; Sakan Maeda; Kou Nagasako

Thirty-seven diminutive flat depressed neoplastic lesions of the colon, smaller than 5 mm, were detected by contrast chromoscopy using an indigo carmine capsule and subsequently removed by endoscopic mucosal resection. We investigated the endoscopic, macroscopic, and histologic characteristics of these lesions and also evaluated the usefulness of chromoscopy and the magnifying endoscope for detecting this type of lesion. The lesions were classified into two types according to the measured height of the histologic sections: 28 lesions were truly flat depressed and the remaining 9 lesions were flat elevated. Of the 37 lesions, 18 were adenomas with mild atypia, 14 with moderate atypia, and 5 with severe atypia. The flat depressed lesions included 12 with mild atypia, 11 with moderate atypia, and 5 with severe atypia. No invasive carcinoma was present in either type, and no adenoma with severe atypia was identified in any of the flat elevated lesions. The overall rate of severe atypia was 13.5%; the rate of severe atypia for the flat depressed type was 17.9%, which is approximately 14-fold greater than that of ordinary diminutive polypoid adenomas (1.3%). The detection of these lesions was facilitated by the use of indigo carmine dye, which clearly demonstrated the mucosal irregularities. The frequency of detection of these lesions was increased four to five times with a magnifying endoscope, as occurred in nearly 10% of all of the patients examined. These data suggest that the finding of endoscopically minute flat depressed neoplastic lesions is not at all uncommon when examination is meticulously performed.(ABSTRACT TRUNCATED AT 250 WORDS)


Human Pathology | 1992

Immunohistochemical study of epidermal growth factor and transforming growth factor-β in the penetrating type of early gastric cancer

Daisuke Hirayama; Takahiro Fujimori; Kazuhiro Satonaka; Tetsuya Nakamura; Souhei Kitazawa; Mitsuzou Horio; Sakan Maeda; Kou Nagasako

We report that the penetrating type of early gastric cancer (PEN) is a specific type of early gastric cancer and that the poorly differentiated PEN type could be considered an initial lesion of linitis plastica-type cancer. We performed an immunohistochemical study to clarify the role of growth factors (epidermal growth factor [EGF] and transforming growth factor-beta [TGF-beta]) in the PEN type of early gastric cancer. The results indicated that the PEN type of early gastric cancer has a high growth capacity. Moreover, it was suggested that EGF was involved in its specific infiltrative growth and that both EGF and TGF-beta were involved in its specific scirrhous growth. From these findings, it was assumed that the immunohistochemical staining of EGF and TGF-beta in endoscopic biopsy specimens was useful for the diagnosis of the PEN type of gastric cancer and also for the diagnosis of the initial lesion of linitis plastica-type gastric cancer.


Human Pathology | 1993

Expression of oncogene products and growth factors in early gallbladder cancer, advanced gallbladder cancer, and chronic cholecystitis.

Masahiko Yukawa; Takahiro Fujimori; Daisuke Hirayama; Yuka Idei; Tetsuo Ajiki; Keisuke Kawai; Reiko Sugiura; Sakan Maeda; Kou Nagasako

The expression of oncogene products and growth factors (epidermal growth factor, transforming growth factor-beta, erbB-2, ras p 21, and c-myc) in gallbladder cancer and chronic cholecystitis was measured by immunohistochemical staining on paraffin-embedded serial sections. Expression of these products was graded according to staining intensity in an area of positively stained cells. This study reports the detection of oncogene products and growth factors in cholecystitis as well as in early and late gallbladder cancer. The multiexpression of oncogene products and growth factors was greater for both gallbladder cancer groups as compared with the cholecystitis group. The percentage of epidermal growth factor positivity diminished with increased proportion of interstitial tissue and, conversely, the percentage of transforming growth factor positivity increased with increased proportion of interstitial tissue. The proportion of ras positivity was significantly greater in both early and advanced cholecystic cancer as compared with cholecystitis, but also was considerable even for cholecystitis. These results suggest that various oncogenes may have significant roles in gallbladder cancer and that collagen synthesis is reduced by epidermal growth factor and enhanced by transforming growth factor-beta.


Gastrointestinal Endoscopy | 1972

Biopsy of the terminal ileum

Kou Nagasako; Chikai Yazawa; Tadayoshi Takemoto

These Japanese experts describe in helpful detail their technic for negotiating by colonoscopy the twists and turns of the bowel in order to obtain biopsy specimens from the terminal ileum. Granular ileal mucosa, reflecting lymphoid hyperplasia, is common in younger patients but probably represents an abnormality in older adults.


Surgery Today | 1995

Expression of p53 protein related to human papillomavirus and DNA ploidy in superficial esophageal carcinoma

Tsutomu Nakamura; Hiroko Ide; Reiki Eguchi; Kazuhiko Hayashi; Fujio Hanyu; Kou Nagasako; Masahiko Yukawa; Kazuyuki Asaka; Takahiro Fujimori; Sakan Maeda

We examined the p53 protein and human papilloma virus (HPV) by immunohistochemistry and DNA ploidy by cytofluorometry in paraffin-embedded esophageal carcinoma tissue specimens. Sixty-one patients with superficial esophageal carcinoma were operated on between 1983 and 1991 without any prior treatment. Immunostaining of the anti-p53 protein antibody (CM1) was positive in 32 carcinomas (52%). Patients with p53-positive tumors had a poorer outcome than those with p53-negative tumors (P<0.05). In addition, patients with p53-positive tumors did not have any characteristic site of relapse. Only 5 of the 61 patients (8.2%) had HPV-positive tumors. One of these 5 carcinomas expressed both p53 protein and HPV. Three patients with HPV-positive tumors which had invaded the submucosal layer died of relapse. A determination of DNA ploidy revealed 30 patients with aneuploid tumors, 13 with polyploid tumors and 18 with diploid tumors. The outcome of the patients with aneuploid tumors was worse than that of the patients with diploid tumor (P<0.05). p53 protein expression was not associated with DNA ploidy; however, the 16 patients who had both p53-positive and aneuploid tumors had a worse prognosis than patients with p53-negative and aneuploid tumors (P<0.01). These findings suggest that p53 protein expression in conjunction with DNA ploidy may be a useful indicator in evaluating the prognosis of patients with superficial esophageal carcinoma.


Gastroenterologia Japonica | 1992

Significance of serum sialic acid in patients with Crohn’s disease

Rika Baba; Kurato Yashiro; Kou Nagasako; Hiroshi Obata

SummarySerum sialic acid was measured to evaluate the activity of Crohn’s disease. The sialic acid levels of patients with Crohn’s disease in remission (CRP 0.0 mg/dl) were significantly higher than those of healthy subjects and postoperative patients with Crohn’s disease. In patients in remission, serum sialic acid was significantly correlated with hemoglobin, hematocrit, platelet, and rapid turnover protein. Correlations with platelet, retinol-binding protein, and prealbumin were especially strong. From these findings, it was concluded that serum sialic acid level provides a useful index of the activity of Crohn’s disease.


Diseases of The Colon & Rectum | 1992

Extensive varices of ileocecum

Shigeki Sugiyama; Kurato Yashiro; Kou Nagasako; Shuichi Sato; Kazuyosi Watanabe; Tatsuki Igarashi; Fujio Hanyu; Hirosi Obata

A man was admitted to our hospital because of intestinal reddish bleeding. Colonic varices were found at the cecum by colonoscopy. Angiography of the superior mesenteric artery showed that blood vessels were scant from the end of the ileum to the ascending colon. An operative view revealed the varices, but there was no trace of the ileocecal vein. This case, presenting a deficit of the ileocecal vein, indicated that the blood flow could not returnviathe ileocecal vein, and therefore there was an outflow through the varices to the surrounding intestine or abdominal veins. Such a case is probably unrepresented in the literature because it was caused by the total deficiency of the ileocecal vein and it was in the right colon.


Gastrointestinal Endoscopy | 1990

Squamous cell metaplasia without dysplasia of the colonic mucosa in ulcerative colitis

Takashi Maruoka; Kaori Hasegawa; Kou Nagasako

There have been only a few reports of squamous cell metaplasia 4 or squamous cell carcinoma1,2.5,6 of the colon associated with ulcerative colitis. We encountered a patient with squamous cell metaplasia and long-standing ulcerative colitis. The lesion was noted endoscopically as a pinkish white area with a clearly demarcated border. Lugol stain and biopsies demonstrated the lesion to be composed of squamous epithelium.


Digestive Endoscopy | 1994

Circumferential Zig‐Zag Pattern Suggesting a Superficial Origin of Colorectal Cancer

Shuichi Sato; Kou Nagasako; Yoshie Takahashi; Motoko Oka; Asako Suzuki; Jongsung Won; Fumi Ishii; Bunei Iizuka; Takahiro Fujimori

Abstract: The early stage of colorectal cancer is divided into two morphological types polypoid and superficial. What percentage of advanced cancer is derived from the polypoid or superficial type is a matter of concern. The ratio of superficial variety among of ulcerated cancers was studied using those 2 cm or less in diameter, which often retain mucosal cancer. The existence of horizontal growing mucosal cancer at the marginal area of ulcerated cancer is a hallmark showing the lesion being of superficial origin. Eight (57 %) out of the 14 cases of ulcerated cancer, 2 cm or less, had this finding. This suggests that more than half of smaller colorectal cancers are of superficial origin. A zig‐zag pattern (ZZP) was evident in 3 cases of superficial origin. No cases in the nonsuperficial group had the ZZP. The existence of circumferential ZZP during colonoscopic observation indicates that the cancer is of superficial origin.


Journal of Gastroenterology | 2000

Clinicopathologic evaluation of the trend toward histologically poor differentiation with submucosal invasion in superficial early colorectal adenocarcinomas

Asako Suzuki; Kou Nagasako; Takahiro Fujimori; Yuko Ono; Shigeru Suzuki; Naoaki Hayashi

Abstract: We examined differences in the degree of differentiation in intramucosal and submucosal areas of involvement in early colorectal adenocarcinomas of 131 patients and compared these findings with tumor morphology. In addition, K-ras and p53 protein expression was determined in cases where poorly differentiated adenocarcinoma was detected in the submucosa. We identified 6 patients with both intramucosal differentiated (well-to-moderately differentiated) adenocarcinoma and submucosal poorly differentiated adenocarcinoma (MwSp). The morphological tumor type was superficial in all MwSp cases. The observed MwSp adenocarcinomas had a significantly higher frequency of lymphatic invasion than the more common superficial type of adenocarcinoma. Genetic analysis of these MwSp lesions was carried out using the polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) method to detect the presence of K-ras codon 12 point mutations, and an immunologic staining technique was used to identify the presence of p53 protein overexpression. The K-ras mutation rate was 33.3%, and the p53 overexpression rate was 66.7% for the MwSp adenocarcinomas. Our findings suggest that the rapidly reduced histologic differentiation observed in some of these superficial colorectal adenocarcinomas may play a role in their higher degree of invasiveness.

Collaboration


Dive into the Kou Nagasako's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Naoaki Hayashi

University of Texas Southwestern Medical Center

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge