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Articles by S Yamamoto
Total Records ( 9 ) for S Yamamoto
  T Ito , S Yamamoto , T Hayashi , M Kodera , H Mizukami , K Ozawa and S. i. Muramatsu

Recombinant adeno-associated virus vectors based on serotype 2 (AAV-2) have become leading vehicles for gene therapy. Most humans in the general population have anti-AAV-2 antibodies as a result of naturally acquired infections. Pre-existing immunity to AAV-2 might affect the functional and safety consequences of AAV-2 vector-mediated gene transfer in clinical applications.


An enzyme-linked immunosorbent assay (ELISA) method was developed using microwell plates coated with intact particles of recombinant AAV-2 vectors, and horseradish peroxidase-conjugated anti-human immunoglobulin G (HRP-IgG). Neutralizing antibody titres were analysed by assessing the ability of serum antibody to inhibit transduction into HEK293 cells of AAV vectors that express β-galactosidase.


Anti-AAV-2 antibodies were detected by ELISA in two of 20 healthy subjects. The positivity criterion (optical density >0.5) in ELISA corresponded to the cut-off value (320-fold dilution of serum) in the AAV-2 neutralization assay. Influences of interfering substances were not observed.


This ELISA method may be useful for rapid screening of anti-AAV-2 neutralizing antibodies in candidates for gene therapy.

  Y Koga , M Yasunaga , A Takahashi , J Kuroda , Y Moriya , T Akasu , S Fujita , S Yamamoto , H Baba and Y. Matsumura

To reduce the colorectal cancer (CRC) mortality rate, we have reported several CRC screening methods using colonocytes isolated from feces. Expression analysis of oncogenic microRNA (miRNA) in peripheral blood was recently reported for CRC detection. In the present study, we conducted miRNA expression analysis of exfoliated colonocytes isolated from feces for CRC screening. Two hundred six CRC patients and 134 healthy volunteers were enrolled in the study. miRNA expression of the miR-17-92 cluster, miR-21, and miR-135 in colonocytes isolated from feces as well as frozen tissues was analyzed by quantitative real-time PCR. The expression of the miR-17-92 cluster, miR-21, and miR-135 was significantly higher in CRC tissues compared with normal tissues. The exfoliated colonocytes of 197 CRC patients and 119 healthy volunteers were analyzed because of the presence of sufficient miRNA concentration. miR-21 expression did not differ significantly between CRC patients and healthy volunteers (P = 0.6). The expression of miR-17-92 cluster and miR-135 was significantly higher in CRC patients than in healthy volunteers (P < 0.0001). The overall sensitivity and specificity by using miRNA expression was 74.1% (146/197; 95% confidence interval, 67.4-80.1) and 79.0% (94/119; 95% confidence interval, 70.6-85.9), respectively. Sensitivity was dependent only on tumor location (P = 0.0001). miRNA was relatively well conserved in exfoliated colonocytes from feces both of CRC patients and healthy volunteers. miRNA expression analysis of the isolated colonocytes may be a useful method for CRC screening. Furthermore, oncogenic miRNA highly expressed in CRC should be investigated for CRC screening tests in the future. Cancer Prev Res; 3(11); 1435–42. ©2010 AACR.

  T Kohno , H Kunitoh , Y Shimada , K Shiraishi , Y Ishii , K Goto , Y Ohe , Y Nishiwaki , A Kuchiba , S Yamamoto , H Hirose , A Oka , N Yanagitani , R Saito , H Inoko and J. Yokota

Adenocarcinoma (ADC) is the commonest histological type of lung cancer, and its weak association with smoking indicates the necessity to identify high-risk individuals for targeted screening and/or prevention. By a genome-wide association study (GWAS), we identified an association of polymorphisms in the 6p21.31 locus containing four human leukocyte antigen (HLA) class II genes with lung ADC risk. DQA1*03 of the HLA-DQA1 gene was defined as a risk allele with odds ratio (OR) of 1.36 [95% confidence interval (CI) = 1.21–1.54, P = 5.3 x 10–7] by analysis of 1656 ADC cases and 1173 controls. DQA1*03 and the minor allele for a polymorphism, rs2736100, in TERT, another lung cancer susceptibility locus identified in recent GWASs on Europeans and Americans, were indicated to independently contribute to ADC risk with per allele OR of 1.43 (95% CI = 1.31–1.56, P = 7.8 x 10–16). Individuals homozygous both for the DQA1*03 and minor TERT alleles were defined as high-risk individuals with an OR of 4.76 (95% CI = 2.53–9.47, P = 4.2 x 10–7). The present results indicated that individuals susceptible to lung ADC can be defined by combined genotypes of HLA-DQA1 and TERT.

  T Kohno , R Kakinuma , M Iwasaki , T Yamaji , H Kunitoh , K Suzuki , Y Shimada , K Shiraishi , Y Kasuga , G. S Hamada , K Furuta , K Tsuta , H Sakamoto , A Kuchiba , S Yamamoto , Y Kanai , S Tsugane and J. Yokota

Estrogen has been indicated to play an etiological role in the development of lung adenocarcinoma (ADC), particularly bronchioloalveolar carcinoma (BAC), a type of ADC that develops from a benign adenomatous lesion, atypical adenomatous hyperplasia (AAH). Polymorphisms in the CYP19A1 gene cause interindividual differences in estrogen levels. Here, 13 CYP19A1 single-nucleotide polymorphisms (SNPs) were examined for associations with lung AAH risk. AAH is detected as ground-glass opacity (GGO) by computed tomography (CT) examination, and this study consisted of 100 individuals diagnosed with GGO in their lungs among 3088 CT-based cancer screening examinees and 424 without. Minor allele carriers for the rs3764221 SNP showed an elevated risk for GGO [odds ratio (OR) = 1.72, P = 0.017]. Associations of this SNP with risks for lung AAH and BAC in the lungs were next examined using 359 ADC cases whose resected lung lobes were subjected to a histological examination for AAH accompaniment and the presence of BAC components and 330 controls without cancer. The ORs were also increased for lung ADC accompanied by AAH (OR = 1.74, P = 0.029) as well as lung ADC with BAC components (OR = 1.41, P = 0.091). The minor allele was associated with an increased circulating estradiol level (P = 0.079) in a population of 363 postmenopausal women without cancer. These results indicate that CYP19A1 polymorphisms are involved in the risk for lung AAH and BAC in the lungs by causing differences in estrogen levels.

  J. J Kazama , R Koda , S Yamamoto , I Narita , F Gejyo and A. Tokumoto

Background and objectives: A new assessment system for bone histology, termed the turnover-mineralization-volume system, is advocated for patients with chronic kidney disease-related mineral and bone disorder. The system measures cancellous bone volume (BV/TV) as a third major evaluation axis; however, the physiologic significance of BV/TV remains unclear.

Design, setting, participants, & measurements: Conventional bone histomorphometry was performed in 75 iliac bone samples obtained from dialysis patients. In 47 of the 75 samples, the remaining samples were subjected to direct microfocus x-ray computed tomographic observation. Quantitative morphologic examinations, including micro-bone mineral densitometry, and marrow space star volume, Euler number, and node-strut analyses, were performed in the virtual three-dimensional space reconstructed from the microfocus x-ray computed tomographic images.

Results: The levels of BV/TV were comparable in each of the conventional bone histomorphometric criteria. No significant correlations were found between BV/TV and other parameters. Two- and three-dimensional BV/TVs were significantly correlated with cancellous bone mass but not with cortical bone thickness or cortical bone mass. Two- and three-dimensional BV/TVs were significantly correlated with trabecular bone connectivity as determined by marrow space star volume, Euler number, and node-strut analyses.

Conclusions: In dialysis patients, BV/TV is not dependent on bone turnover or bone mineralization. BV/TV is unlikely to indicate the balance between bone formation and bone resorption. Instead, it reflects trabecular bone connectivity, and improved trabecular bone connectivity is physiologically beneficial in terms of bone quality. The turnover-mineralization-volume system offers an advantage over the conventional system for the assessment of bone quality.

  S Yamamoto , S Kawakami , J Yonese , Y Fujii , T Tsukamoto , Y Ohkubo , Y Komai , Y Ishikawa and I. Fukui

The aim of this study was to assess the surgical outcome of high-grade prostate cancer (PCA) treated with antegrade radical prostatectomy with intended wide resection (aRP) and to establish the risk stratification.


A consecutive 77 Japanese patients with Gleason score 8–10 PCA were treated with aRP alone and excluding patients with persistently elevated prostate-specific antigen (PSA), prospectively observed without any treatment until PSA failure was confirmed. PSA failure-free, cancer-specific and overall survival curves were generated with Kaplan–Meier method and the difference between groups was assessed with log-rank test. Cox's proportional hazards model was used to elucidate predictors of PSA failure.


During a median follow-up of 6 years, PSA failure was observed in 41 (53%) of the 77 patients. Five- and 10-year PSA failure-free survival rates of the entire cohort were 44.6% and 40.1%, respectively. Both overall and cancer-specific survival rates of the entire cohort at 5 and 10 years were 96.8% and 87.9%, respectively. In a multivariate analysis, PSA (P = 0.008), specimen confinement (SC) (P = 0.006) and persistently elevated PSA after aRP were identified as significant and independent predictors of PSA failure. When stratifying patients into three risk groups according to PSA level and SC status, PSA failure-free survival rate in patients with PSA < 10 ng/ml and specimen-confined disease (SCD) was significantly better than that in those of any other groups.


Good prognosis can be expected in patients with high-grade PCA treated with aRP alone when PSA < 10 ng/ml and the tumor was removed as an SCD.

  T Wakahara , S Yamamoto , S Fujita , T Akasu , S Onouchi and Y. Moriya

Adenocarcinoid tumor most commonly occurs in the appendix and a tumor arising in the rectum is extremely rare. A 58-year-old man underwent total pelvic exenteration with extended lateral lymph node dissection for rectal adenocarcinoid tumor invading the urethra with lateral lymph node metastasis. Microscopically and immunohistochemically, the tumor consisted of carcinoid-like components and signet-ring-cell-carcinoma-like components, and an adenocarcinoid tumor was diagnosed. Postoperatively, the patient received combination chemotherapy of fluorouracil and leucovorin as an adjuvant therapy. Three years and 5 years after the initial surgery, the patient developed left groin and left external iliac lymph node recurrences, and lymphadenectomy was performed each time. As a result, the patient is alive more than 5 years after the initial surgery. There is no consensus on the indication of surgical treatment for adenocarcinoid tumor. However, in advanced cases, an aggressive surgical procedure might result in long-term survival when resectable.

  Y Hayashi , M Yamamoto , H Mizoguchi , C Watanabe , R Ito , S Yamamoto , X. y Sun and Y. Murata

Multiple bioactive peptides, including glucagon, glucagon-like peptide-1 (GLP-1), and GLP-2, are derived from the glucagon gene (Gcg). In the present study, we disrupted Gcg by introduction of GFP cDNA and established a knock-in mouse line. Gcggfp/gfp mice that lack most, if not all, of Gcg-derived peptides were born in an expected Mendelian ratio without gross abnormalities. Gcggfp/gfp mice showed lower blood glucose levels at 2 wk of age, but those in adult Gcggfp/gfp mice were not significantly different from those in Gcg+/+ and Gcggfp/+ mice, even after starvation for 16 h. Serum insulin levels in Gcggfp/gfp mice were lower than in Gcg+/+ and Gcggfp/+ on ad libitum feeding, but no significant differences were observed on starvation. Islet -cells and intestinal L-cells were readily visualized in Gcggfp/gfp and Gcggfp/+ mice under fluorescence. The Gcggfp/gfp postnatally developed hyperplasia of islet -cells, whereas the population of intestinal L-cells was not increased. In the Gcggfp/gfp, expression of Aristaless-related homeobox (Arx) was markedly increased in pancreas but not in intestine and suggested involvement of Arx in differential regulation of proliferation of Gcg-expressing cells. These results illustrated that Gcg-derived peptides are dispensable for survival and maintaining normoglycemia in adult mice and that Gcg-derived peptides differentially regulate proliferation/differentiation of -cells and L-cells. The present model is useful for analyzing glucose/energy metabolism in the absence of Gcg-derived peptides. It is useful also for analysis of the development, differentiation, and function of Gcg-expressing cells, because such cells are readily visualized by fluorescence in this model.

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