Biomedical subjects

Tooru Shimosegawa

Publications and source records attributed to Tooru Shimosegawa.

131 records · Page 8Linked to original sources

PubMedDate not supplied

Correlative polymorphism of NAD(P)H: quinone oxidoreductase (NQO1) with telomere shortening in colorectal cancer.

AIM: The aim of this study was to examine whether and relationships could be found among polymorphism of the NQO1 gene, telomere length and telomerase activity in colorectal cancers. MATERIALS AND METHODS: Fifty-one invasive colorectal cancers were studied. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was undergone to detect mutation of the NQO1 gene. Telomere length was examined by Southern blot analysis. Telomerase activity was assayed by telomeric repeat amplification protocol with minor modifications. RESULTS: Of the 51 tumors, 20 (39.2%) and 9 (17.6%) were heterozygous and homozygous for the mutation, respectively. Most of the cases homozygous for the mutation (88.9%) showed short telomeres and its frequency was significantly higher than in those heterozygous (p = 0.0432). However no relationship was found between the telomerase activity and mutation in the NQO1 gene. CONCLUSION: Our data suggest that oxidative stress by the lack of NQO1 activity could result in telomere shortening through colorectal cancinogenesis.

Aged↗

PubMedDate not supplied

High Ki-67 labeling index in human colorectal cancer with microsatellite instability.

BACKGROUND: In the present study, we examined the relationships between microsatellite status and Ki-67 labeling index, a proliferative marker, in colorectal cancers in order to clarify the common biological profiles of familial and sporadic cases of MSI (microsatellite inability)-positive tumors. PATIENTS AND METHODS: Seventy-eight invasive colorectal carcinomas were studied. Five microsatellite loci were analyzed by polymerase chain reaction, while Ki-67 was studied by immunohistochemistry. RESULTS: The MSI was found in 15 (19.2%) of the 78 tumors, and the Ki-67 labeling index was significantly higher in the 15 MSI-positive tumors than that in the 15 MSI-negative ones (p = 0.0181). Moreover, the Ki-67 labeling index was significantly higher in the 7 tumors with MSI at more than 2 loci (MSI-H; high-frequency MSI) than that in the MSI-negative ones (p = 0.0082). CONCLUSION: The present study demonstrates that colorectal cancers with MSI show high Ki-67 labeling index irrespective of hereditary or nonfamilial cancer types, suggesting their common biological aspects distinct from MSI-negative ones.

Aged↗

PubMedDate not supplied

Photodynamic therapy of intestinal tumors with mono-L-aspartyl chlorin e6 (NPe6): a basic study.

BACKGROUND: To clarify the usefulness of the second-generation photosensitizer, mono-L-aspartyl chlorin e6 (NPe6), we examined the possibility of photodynamic diagnosis and photodynamic therapy for intestinal tumors in a mouse model. MATERIALS AND METHODS: NPe6 was intravenously administered to the tumor-bearing mice through the tail vein. The intestinal tumor sites were irradiated with a 664-nm diode laser at constant intervals after the administration of photosensitizers. The tumors were excised and fluorescence was observed in frozen sections by microscope. RESULTS: We observed the fluorescent image and calculated that the mean fluorescence intensity was significantly higher in the tumors than the normal mucosa during 6 hours (p < 0.05). The fluorescence of NPe6 was chiefly accumulated in the intestinal tumors as red fluorescence on the fluorescent microphotographic image. CONCLUSION: We conclude that NPe6 may be a valuable photosensitizer for the photodynamic diagnosis and photodynamic therapy of intestinal tumors.

Animals↗

PubMedDate not supplied

Multiparameter analysis for discreet differential diagnosis of mucosa-associated lymphoid tissue lymphoma in the intestine.

BACKGROUND: The diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma in the intestine is occasionally difficult from histological examination on small biopsy specimens obtained by endoscopy. This study focused on unusual cases of reactive lymphoproliferative disorders in the intestine in order to make a differential diagnosis of MALT lymphoma. MATERIALS AND METHODS: Five patients were examined with regards to clinical symptoms, endoscopic findings and multiparameter analysis (the morphological examination using routine hematoxylin and eosin staining by light microscopy, immunophenotyping by flow cytometry (FCM), immunohistochemistry and genotyping of extracted DNA). RESULTS: All cases showed an aggregation of lymphocytes and one case showed similar features to lymphoepithelial lesions. Analyses of FCM and genetic rearrangements denied the monoclonality in all cases. Consequently, we considered that all cases should be diagnosed as reactive lymphoid hyperplasia and inflammatory change. CONCLUSION: Multiparameter analysis is useful in making an exact diagnosis of MALT lymphoma and therefore contributes to prevent unnecessary overtreatment.

Adolescent↗

PubMedDate not supplied

In situ androgen production in human gastric carcinoma--androgen synthesizing and metabolizing enzymes.

BACKGROUND: It is well known that the incidence of gastric carcinoma is lower in females than in males. Therefore, androgens have been proposed to play an important role in modifying the development of gastric carcinoma. 5Alpha-reductase (5alpha-reductase) types 1 and 2 and 17beta-hydroxysteroid dehydrogenase type 5 (17beta-HSD type 5) are considered important local regulators of androgen production in human androgen-responsive tissues and cancer. MATERIALS AND METHODS: The immunoreactivities of these steroidogenic enzymes, as well as of the androgen receptor (AR), were evaluated in human gastric carcinoma obtained from endoscopic mucosal resection (EMR) (n = 117). RESULTS: 17beta-HSD type 5 immunoreactivity was detected in 99 cases (85%), 5alpha-reductase type 1 in 69 cases (59%), 5alpha-reductase type 2 in 57 cases (49%) and AR in 46 cases (39%). CONCLUSION: These androgen-producing enzymes are expressed in human gastric carcinomas and are involved in the in situ production and possible regulation of androgenic activity in human gastric carcinoma.

17-Hydroxysteroid Dehydrogenases↗