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Biomedical subjects

T Suto

Publications and source records attributed to T Suto.

At least 19 recordsLinked to original sources
PubMed2001

Infrequent microsatellite instability in biliary tract cancer.

BACKGROUND AND OBJECTIVES: Microsatellite instability (MSI) has been reported in several tumors. However, few reports are available concerning MSI in biliary tract cancers. We investigated MSI and allelic loss at the hMLH1 and hMSH2 gene loci in biliary tract cancers. METHODS: We analyzed microsatellite alterations using 7 microsatellite markers in 38 cases of extrahepatic bile duct (EHBD) cancer and 16 cases of ampullary cancer using polymerase chain reaction and an automated fluorescent DNA sequencer. RESULTS: A MSI prevalence of 13.2% (5/38) was observed for EHBD cancer and a prevalence of 12.5% (2/16) was observed for ampullary cancer. Loss of heterozygosity at the hMLH1 and hMSH2 gene loci were observed in 4% (1/25 informative cases) and 6.1% (2/33) of EHBD cancer cases, respectively; and in 11.1% (1/9) and 8.3% (1/12) of ampullary cancer cases, respectively. The cumulative survival rate of patients with MSI was significantly better than that of patients without MSI in EHBD cancer. However, MSI was not an independent prognostic factor. CONCLUSIONS: Our results suggest that genetic defects in the DNA mismatch repair system and MSI do not play an important role in the majority of biliary tract cancers.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Prognostic significance of lymph node involvement in middle and distal bile duct cancer.

BACKGROUND: Although lymph node involvement is considered an important prognostic factor, a detailed analysis has not been conducted in middle (Bm) and distal (Bi) bile duct cancer. METHODS: The histopathology of resections taken from 59 patients with Bm and Bi disease (Bm, 33 patients; Bi, 26 patients) was examined. The prevalence of lymph node involvement and its relationship to recurrence and prognosis were investigated. Survival rates were investigated according to the number of metastatic lymph nodes found, the TNM nodal stages, and the nodal stage classifications of The General Rules of the Japanese Society of Biliary Surgery. RESULTS: The frequency of nodal involvement in Bm and Bi was 45.5% and 30.8%, respectively. A significant correlation existed between a patient's prognosis and his TNM nodal stage, Japanese Society of Biliary Surgery nodal stage, and the number of metastatic lymph nodes found (P <.0001, respectively). Among 8 sites of postoperative recurrence, metastasis occurred most frequently in the liver (16/23). Patients with nodal involvement had a significantly higher rate of liver metastasis (10/23) than those without it (6/36) (P =.024). CONCLUSIONS: The number of metastatic lymph nodes found in patients with Bm or Bi cancer, and the nodal stage of their nodes, are significant prognostic indicators. Patients with nodal involvement are at high risk for liver metastasis in Bm and Bi disease.

Adult↗
PubMed2000

DNA mapping of gastric cancers using flow cytometric analysis.

Although numerous studies of gastric cancers on DNA ploidy have been reported, differences in the degree of aneuploidy (DNA index, DI) during progression have not been identified. We attempted to chart the differences in DIs during progression to clarify the role of aneuploidy in gastric cancers. We classified the gastric cancers examined into intestinal (n = 88) and diffuse (n = 48) types, and then analyzed 136 gastric cancers (intramucosal cancer, 42; submucosal cancer, 39; advanced cancer, 55) by flow cytometry using multiple sampling. In addition, we examined the DNA ploidy pattern of mucosal and submucosal lesions using the same submucosal cancers to study the tumor progression in individual cancers. Intratumoral DNA differences in DNA ploidy were observed in both types of gastric cancers. In intestinal-type cancers, multiple subclones indicated by a different DI occurred during the early stage of gastric cancers, whereas in diffuse-type cancers, multiple subclones were found primarily in advanced cancers. Although the DI varied widely in early intestinal-type cancers between 1.0 and 2.0, in early diffuse-type cancers, the DI tended to be less than 1.2. However, in advanced stage gastric cancers, the DI distribution was similar for both histological types. In intestinal-type cancers, high DI (>1.3) aneuploidy was frequently found in mucosal lesions. In contrast, only low DI (<1.2) aneuploid clones were observed in mucosal lesions of diffuse-type cancers. The present results suggest that high DI aneuploid tumor clones in intramucosal cancers acquire invasive ability when they progress to submucosal cancers, whereas DNA aneuploidy itself plays an important role in submucosal invasion of diffuse-type cancers.

Adult↗
PubMed2000

Aberrations of the K-ras, p53, and APC genes in extrahepatic bile duct cancer.

BACKGROUND AND OBJECTIVES: The genetic alterations involved in extrahepatic bile duct (EHBD) cancer are poorly understood. Our aim was to identify aberrations of the K-ras, p53, and APC genes in EHBD cancer. METHODS: We investigated aberrations of these genes in 52 EHBD cancers using polymerase chain reaction (PCR) single-strand conformation polymorphism analysis, followed by direct sequence determination and a PCR restriction fragment length polymorphism assay. RESULTS: The K-ras, p53, and APC genes were mutated in 9.6%, 32.7%, and 0% of EHBD cancers, respectively. Loss of heterozygosity at the p53 and APC gene loci was identified in 15.6% and 38.5% of EHBD cancers, respectively. CONCLUSIONS: Our results suggest that an unknown suppressor gene on 5q other than the APC gene may be responsible for EHBD cancer.

Aged↗
PubMed2000

An automated prediction of MHC class I-binding peptides based on positional scanning with peptide libraries.

Specificities of three mouse major histocompatibility complex (MHC) class I molecules, Kb, Db, and Ld, were analyzed by positional scanning using combinatorial peptide libraries. The result of the analysis was used to create a scoring program to predict MHC-binding peptides in proteins. The capacity of the scoring was then challenged with a number of peptides by comparing the prediction with the experimental binding. The score and the experimental binding exhibited a linear correlation but with substantial deviations of data points. Statistically, for approximately 80% of randomly chosen peptides, MHC-binding capacity could be predicted within one log concentration of peptides for a half-maximal binding. Known cytotoxic T-lymphocyte epitope peptides could be predicted, with a few exceptions. In addition, frequent findings of MHC-binding peptides with incomplete or no anchor amino acid(s) suggested a substantial bias introduced by natural antigen processing in peptide selection by MHC class I molecules.

Animals↗
PubMed2000

Clarithromycin-resistance and point mutations in the 23S rRNA gene in Helicobacter pylori isolates from Japan.

BACKGROUND: Resistance of Helicobacter pylori to clarithromycin is mostly due to the point mutations in the 23S rRNA. In Japan, however, the frequency of these mutations has not been fully investigated. Furthermore, no study has used gastric biopsy specimens to detect these point mutations. METHODS: The frequency of primary clarithromycin-resistant H. pylori was examined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Eighty-two strains (42 isolated from patients with gastric cancer and 40 isolated from patients with chronic gastritis) were examined. Two biopsy specimens obtained from patients in whom eradication therapy including clarithromycin had failed were also studied. RESULTS: Either A2143G or A2144G point mutation was detected in 90% of clarithromycin-resistant H. pylori strains. Eight out of 82 strains (9.8%) had either A2143G or A2144G point mutation. Only one out of 42 strains in patients with gastric cancer had A2143G mutation, whereas five strains had A2144G and two had A2143G mutations in 40 strains isolated from control subjects. The proportion was significantly lower in patients with early gastric cancer (P < 0.05). This PCR-RFLP was also applicable for DNA samples extracted from biopsy specimens and infection of clarithromycin-resistant H. pylori was observed. CONCLUSION: The results suggest that the point mutation in the 23S rRNA gene is commonly seen in clarithromycin-resistant H. pylori and it contributes to the treatment failure in Japan. The PCR-RFLP system is a sensitive method by which to diagnose H. pylori infection as well as a simple method for detecting clarithromycin resistance without bacterial culture.

Anti-Bacterial Agents↗
PubMed1999

Role of DNA aneuploidy, overexpression of p53 gene product, and cellular proliferation in the progression of gastric cancer.

DNA aneuploidy, p53 overexpression, and high cell proliferation frequently occur in gastric cancer. However, little is known about the time of their appearance throughout cancer progression. Therefore, the objective of the present study was to determine when such abnormalities occur during gastric cancer progression. We classified the gastric cancers examined into intestinal (n = 65) and diffuse (n = 34) types. DNA ploidy was examined using flow cytometry and expression of MIB-1 and p53 immunoreactivity were studied using the avidin-biotin complex method in three stages of gastric cancer (mucosal, submucosal, deeply invasive cancer, i.e., advanced cancer). The incidence of DNA aneuploidy in intestinal-type mucosal cancers (15/27, 55.6%) was lower than that of submucosal invasive cancers (14/16, 87.5%) or advanced cancers (19/22, 86.4%), while a low incidence of DNA aneuploidy was observed in each diffuse-type cancer group (mucosal, 1/12, 8.3%; submucosal invasive, 3/9, 33.3%; advanced, 8/14, 57.1%). Although overexpression of the p53 gene in intestinal-type cancer was found in early stage, that in diffuse-type cancer was observed in advanced stage. Among the intestinal-type mucosal cancers, the MIB-1 percent positive was higher in aneuploid tumors than diploid ones. DNA aneuploidy and overexpression of the p53 gene may play an important role in the early tumorigenesis of intestinal-type gastric cancer and in the late event of tumorigenesis of diffuse-type gastric cancer.

Aged↗
PubMed1999

High-dose natural interferon-alpha therapy for chronic hepatitis C with a high viral load: predictors of efficacy. The Aomori, Akita and Iwate Areas Viral Hepatitis Research Group.

BACKGROUND: The effectiveness of interferon against hepatitis C has been found to be greatly affected by viral factors. However, few controlled interferon trials have involved seemingly intractable cases of chronic hepatitis C. METHODS: In 44 patients with high hepatitis C virus RNA levels (> or = 10(5) copies/mL), we carried out a prospective, controlled study of two natural interferon-alpha regimens, seeking predictors of therapeutic efficacy. Total natural interferon-alpha doses over 6 months in two groups were 780 and 840 million units, respectively. RESULTS: High therapeutic efficacy was achieved with no significant outcome difference between the regimens. The virus eradication rate was 35% and the rate of sustained biochemical response was 45% for both regimens. Multivariate logistic regression analysis identified viral genotype as the only significant predictor of success in viral eradication. CONCLUSIONS: Hepatitis C virus genotype 2 showed high sensitivity to interferon-alpha and this therapy can be recommended even for patients with a high viral load of this genotype. In contrast, with genotype 1b, cure was extremely difficult in cases with 10(7) or more copies/mL with a single 6-month course of interferon-alpha.

Adult↗
PubMed1999

Biological properties of opioid peptides replacing Tyr at position 1 by 2,6-dimethyl-Tyr.

To understand the effect of the replacement of Tyr residue at position 1 in opioid peptides by 2,6-dimethyl-Tyr (Dmt) on the biological property, chiral (D or L) Dmt1 analogs of Leu-enkephalin (Enk) and Tyr-D-Arg-Phe-beta Ala-NH2 (YRFB) were synthesized and their enzymatic stabilities, in vitro bioactivities and receptor binding affinities compared with those of parent peptides. [L-Dmt1]Enk (1) exhibited 4-fold higher stability against aminopeptidase-M and possessed dramatically increased activities in guinea pig ilium (GPI) (187-fold) and mouse vas deferens (MVD) (131-fold) assays, and in rat brain receptor binding assays (356-fold at mu receptor and 46-fold at delta receptor) as compared to Enk. [L-Dmt1]YRFB (3) also exhibited increased activities in GPI (46-fold) and MVD (177-fold) assays, and in the binding assays (69-fold at mu receptro and 341-fold at delta receptor) as compared to the parent peptide. [D-Dmt1]Enk (2) and [D-Dmt1]YRFB (4) exhibited activities with diminished or lesser potency than the parent peptide in all assays. These results indicate that there is a tendency for mu affinity to be enhanced more than delta affinity with introduction of L-Dmt into delta ligand peptide (Enk), and for delta affinity to be enhanced more than mu affinity in case of mu ligand peptide (YRFB), resulting in reduced receptor selectivities at the receptors.

Animals↗
PubMed1998

Assessment of the expression of p53, MIB-1 (Ki-67 antigen), and argyrophilic nucleolar organizer regions in carcinoma of the extrahepatic bile duct.

BACKGROUND: The authors retrospectively examined the predictive value of p53, MIB-1, and the argyrophilic nucleolar organizer regions (AgNOR) and examined the relationships among them in carcinoma of the extrahepatic bile duct (EHBD). METHODS: Formalin fixed, paraffin embedded specimens from 54 patients with EHBD carcinoma were immunostained with MIB-1 against the Ki-67 nuclear antigen and p53 by the avidin-biotin peroxidase complex method, using the antigen retrieval technique of heating tissue sections in a microwave oven. The AgNOR proteins were localized at the optical level, as shown by a one-step silver staining technique. RESULTS: MIB-1 and AgNOR were closely associated with lymph node metastasis (P < 0.01). The cumulative survival rate for patients with a low MIB-1 labeling index (LI) (< 29%) was significantly better than that for patients with a high MIB-1 LI (> or = 29%) in cases of EHBD carcinoma (P < 0.05), but MIB-1 was not an independent prognostic factor in multivariate analysis. The results indicated that AgNOR and p53 overexpression had no prognostic value. The authors detected p53 in 24 of the 54 EHBD carcinomas (44.4%). There was a significant correlation between MIB-1 and AgNOR (P < 0.01). The authors found that neither MIB-1 nor AgNOR correlated with p53 overexpression. CONCLUSIONS: MIB-1 and AgNOR proved to be useful predictors of lymph node metastasis. The results of this study indicated that MIB-1 and AgNOR might be markers of the progression of EHBD carcinoma.

Adult↗
PubMed1998

Correlation of histologic morphology and tumor stage with molecular genetic analysis using microdissection in gastric carcinomas.

Precise correlation of histomorphology with the results of molecular genetic analysis is difficult in gastric cancer tissue composed of intestinal and diffuse types. A novel microdissection procedure was applied to correlate p53 and APC allelic loss with histologic type and tumor stage (mucosal vs. invasive cancer) in formalin-fixed, paraffin-embedded specimens of 25 gastric cancers. In addition, mucosal and invasive lesions were dissected from each of 11 invasive gastric cancers to study progression, and allelic loss of the p53 and APC genes was assessed. The p53 gene underwent loss of heterozygosity (LOH) in 4 of 4 informative cases of intestinal-type gastric cancer with mucosal lesions associated with invasion. By contrast, no p53 LOH was found among 6 informative cases with mucosal cancer. LOH of the APC gene in both intestinal and diffuse types of cancer was detected in 4 of 7 and 5 of 6 informative cases, respectively. These data suggest that allelic deletion of the p53 gene in intestinal-type gastric carcinoma predicts the invasive potential of mucosal cancer, and that inactivation of the APC gene plays a role in the genetic tumorigenesis of both intestinal and diffuse types of gastric cancer. Microdissection can correlate genetic alterations with histologic morphology in gastric cancer.

Adenocarcinoma↗
PubMed1998

Cloning and characterization of the genomic RNA sequence of the mumps virus strain associated with a high incidence of aseptic meningitis.

cDNA clones of the mumps virus wild-type strain, associated with a high incidence of aseptic meningitis (ODATE-1 strain), were isolated and analyzed from genomic nucleotide position 22 to 8520 containing the NP, P, M, F, SH and HN protein coding region. The ODATE-1 strain exhibited a RFLP profile identical to that of the Urabe vaccine strain in spite of the fact that the virus was isolated from non-vaccinated cases. However, a comparison of nucleotide and amino acid sequences among the ODATE-1 strain, Urabe strain and Miyahara strain revealed that the ODATE-1 strain was not related to the Urabe strain.

Animals↗