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Masahiro Sasaki

Publications and source records attributed to Masahiro Sasaki.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of the diagnostic performance of FDG-PET and VBM-MRI in very mild Alzheimer's disease.

PURPOSE: The aim of this study was to compare the diagnostic performance of( 18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and voxel-based morphometry (VBM) on magnetic resonance imaging (MRI) in the same group of patients with very mild Alzheimer's disease (AD). METHODS: Thirty patients with very mild AD (age 67.0+/-5.8 years; MMSE score 25.5+/-1.2, range 24-28), 32 patients with mild AD (age 67.0+/-4.5 years, MMSE score 22.1+/-0.8, range 21-23) and 60 age- and sex-matched normal volunteers underwent both FDG-PET and three-dimensional spoiled gradient echo MRI. Statistical parametric mapping was used to conduct voxel by voxel analysis and Z score mapping. First, the region of interest (ROI) maps of significant reductions in glucose metabolism and grey matter density in the mild AD patients were defined. Secondly, analysis of receiver operating characteristic (ROC) curves for Z scores in the ROI maps discriminating very mild AD patients and normal controls was performed. RESULTS: In mild AD patients, FDG-PET indicated significant reductions in glucose metabolism in the bilateral posterior cingulate gyri and the right parietotemporal area, while VBM analysis showed a significant decrease in grey matter volume density in the bilateral amygdala/hippocampus complex, compared with the normal control group. ROC analysis showed that in very mild AD patients the accuracy of FDG-PET diagnosis was 89% and that of VBM-MRI diagnosis was 83%. The accuracy of the combination of FDG-PET and VBM-MRI diagnosis was 94%. CONCLUSION: In very mild AD, both FDG-PET and VBM-MRI had high accuracy for diagnosis, but FDG-PET showed slightly higher accuracy than VBM-MRI. Combination of the two techniques will yield a higher diagnostic accuracy in very mild AD by making full use of functional and morphological images.

Aged↗
PubMed2006

Necessity of a uniform start for scanning after FDG injection in brain PET study.

UNLABELLED: The authors' goal was to show the importance of starting scanning at a uniform time after F-18 fluorodeoxyglucose injection in positron emission tomography (PET) brain study. METHOD: Fifteen healthy normal subjects underwent FDG-PET to obtain glucose metabolic images starting 60 min and 70 min after FDG injection, respectively. The two sets of images were compared in a voxel-by-voxel analysis. RESULTS: In the bilateral posterior cingulate gyrus, parietal and frontal association cortices, the FDG uptakes were larger on the 70 min scan images than on the 60 min scan images; the 60 min scans resembled Alzheimer's metabolic reduction area. Similarly the FDG uptakes were larger in the pons and vermis on the 60 min scan image than on the 70 min scan image. CONCLUSIONS: Regional FDG uptake is different depending on the time scanning starts after FDG injection, even with a 10 minute difference in start time and different scanning time may lead to misdiagnosis. It is important to standardize the start time of FDG PET after FDG injection in brain PET.

Adult↗
PubMed2006

Effect of the silk protein sericin on the production of adenovirus-based gene-therapy vectors.

Adenoviral vectors are extensively used as gene-delivery vehicles in gene therapy. They are usually produced by HEK-293 cell (human embryonic kidney-293 cell) culture, which requires specially formulated serum-free medium, the cost of which is considerable or by supplementation with FBS (fetal bovine serum). The risk of infectious diseases such as BSE (bovine spongiform encephalopathy) and endogenous retrovirus derived from cattle is a serious concern. The present study reports the use of sericin protein derived from silkworm (Bombyx mori) as an effective supplement instead of FBS. Without FBS, HEK-293 cells significantly proliferated in the presence of 0.025-0.4% sericin, especially at 0.1%, but the effect was inferior to that of FBS. When a lower titre [MOI (multiplicity of infection) 0.03] of adenoviral vector pAxCAiLacZ was used as the inoculum, HEK-293 cells in the presence of 0.1% sericin produced a nearly 3-fold higher vector titre than culture in the presence of 5% (v/v) FBS. However, when a higher vector titre (MOI 3.7) was used as the inoculum, HEK-293 cells in the presence of sericin produced a slightly higher vector titre than in the presence of FBS, which might suggest that HEK-293 cells produce a maximum amount when a higher vector titre is used as the inoculum. These increases in vector production with sericin were confirmed by LacZ (beta-galactosidase reporter gene) activity assay. Supplementation with sericin decreased lactate dehydrogenase activity, an indicator of cell death, suggesting that sericin improved cell survival; hence, prolonging the culture period might be one of the reasons for increased vector production. On the basis of these results, sericin peptide seems to be a potent and effective alternative supplement for production of adenoviral vectors without such risks as BSE and retrovirus.

Adenoviridae↗
PubMed2006

Catechol-O-methyltransferase gene polymorphisms in benign prostatic hyperplasia and sporadic prostate cancer.

Various carcinogenic metabolites, including catechol estrogens, play a role in malignant transformation. An enzyme that is capable of neutralizing the genotoxic effects of these compounds is catechol-O-methyltransferase (COMT). A variant form of this enzyme has been shown to reduce its activity by up to 4-fold; thus, we hypothesize that single nucleotide polymorphisms of the COMT gene can be a risk factor for benign prostatic hyperplasia (BPH) and prostate cancer. To test this hypothesis, the genetic distribution of three different COMT polymorphisms at codon 62 (C-->T), codon 72 (G-->T), and codon 158 (G-->A) were analyzed in 131 normal healthy subjects, 134 BPH, and 178 sporadic prostate cancer samples from a Japanese population. Results of these experiments show that the variant genotype at codon 62 (P = 0.060) and codon 158 (P = 0.047) are risk factors for prostate cancer but not BPH when compared with normal controls. Odds ratio (OR) and 95% confidence interval (95% CI) for cancer were 3.24 and 1.38 to 7.61, respectively, for codon 62 T/T genotype when compared with wild type. At codon 158, the A/A variant for cancer had an OR of 3.00 with a 95% CI of 1.38 to 6.54 compared with wild type. Codons 62 and 158 were in linkage disequilibrium (LD), and when compared with the C-G haplotype, other types (C-A, T-G, T-A) were observed to be associated with prostate cancer (P = 0.040) but not BPH. Codon 72 on the other hand, was not in LD with either codon 62 or 158. The homozygous variant on codon 72 was rare in this Japanese population, and the heterozygous G/T at this codon was not associated with either prostate cancer or BPH. When evaluating the risk of COMT polymorphisms with stage or grade of cancer, no associations were observed for any of the genotypes with the exception of a tendency (P = 0.096) for the variant A allele on codon 158 to be correlated with higher stages (> or = T3) of cancer. This is the first report that shows the polymorphisms of COMT to be associated with sporadic prostatic carcinogenesis. These results are important in understanding the role of COMT polymorphisms in the pathogenesis of prostate cancer.

Alleles↗
PubMed2006

[Predicted vales of respiratory function tests in young Japanese aged from 10 to 20 years].

To find predicted values of respiratory function tests in young persons in Japan, we measured slow vital capacity and forced vital capacity in 1,141 subjects aged from 10 to 20 years. The values obtained from 636 persons (363 males and 273 females) who were not smokers or had no suspected rhinitis or asthma were analyzed. Although FEV1% by the Gaensler and Tiffeneau methods were almost constant regardless of age, all other values of respiratory function tests increased with age and then reached a plateau level in late teens. Excluding the Gaensler and Tiffeneau FEV1%, in a single regression analysis using gender, age, and height, both the contribution ratio and regression coefficient were the highest using height, followed by age. In addition, the result was similar with multiple regression analysis. Therefore, for a young person aged from 10 to 20 years, body height is the most important predictor variable of respiratory function tests, compared to gender and age. For each respiratory function test, we showed the prediction relation according to gender obtained from multiple linear regression analysis using 2 variables of height and age.

Adolescent↗
PubMed2005

WT1 and WT1-AS genes are inactivated by promoter methylation in ovarian clear cell adenocarcinoma.

BACKGROUND: Ovarian clear cell adenocarcinoma is associated with one of the poorest prognoses among human epithelial ovarian cancers. The authors hypothesized that Wilms tumor suppressor 1 gene (WT1) sense and antisense (WT1-AS) expression and their promoter methylation status could characterize ovarian clear cell adenocarcinoma from ovarian serous adenocarcinoma. METHODS: To test this hypothesis, ovarian cancer cell lines and 42 cancer tissues (17 clear cell and 25 serous adenocarcinoma) were analyzed for expression and methylation of WT1 and WT1-AS genes. RESULTS: These experiments demonstrated that all serous adenocarcinoma tissues expressed both WT1 and WT1-AS genes, although expression of these genes was lacking in clear cell adenocarcinoma. The WT1 and WT1-AS promoter were significantly methylated in clear cell adenocarcinoma (88.2% and 88.2%, respectively) compared with serous adenocarcinoma (24.0% and 20.0%, respectively). Significant correlation between methylation and mRNA expression status was observed for each gene. Also in agreement with these data, WT1 and WT1-AS negative ovarian cancer cell lines reexpressed these genes after treatment with the demethylating agent, 5-aza-2'-deoxycytidine. CONCLUSIONS: The current study shows that CpG hypermethylation is an important mechanism of WT1 and WT1-AS gene inactivation in ovarian clear cell adenocarcinoma. This is the first report that has demonstrated differential expression and methylation of WT1-AS in ovarian clear cell and serous adenocarcinomas. This study presents new molecular characterizations between these two types of adenocarcinoma and may provide insight as to why clear cell adenocarcinoma has a poorer prognosis than serous adenocarcinoma of the ovary.

Adenocarcinoma, Clear Cell↗
PubMed2005

A molecular-beam study of the collision dynamics of methane and ethane upon a graphitic monolayer on Pt(111).

Utilizing a supersonic molecular-beam scattering technique, the angular intensity distributions of alkane molecules (CH4 and C2H6) have been measured, which are scattered from a chemically inert and highly oriented monolayer graphite (MG) on Pt(111). A MG which covers the Pt(111) surface with a full monolayer is found to induce a large energy loss of alkanes during collision with the surface by phonon creation due to the large mass ratio of an alkane molecule with respect to MG. Based on the classical cube model, only applicable to the molecules without internal mode excitation, the effective masses of MG of 76 (six atoms of carbon) and Pt(111) of 585 (three atoms of platinum) are determined from rare-gas atom scattering data. Despite the difference in the degree of freedom between CH4 and rare-gas atoms, CH4 scattering is found to be well described by the simple hard-cube model as a result of the high symmetry of the CH4 structure. With the recently developed ellipsoid-washboard model, an extension of the hard-cube model to include some internal mode excitation of impinging molecules in addition to the surface corrugation, it is found that unlike CH4 the cartwheel rotation mode of C2H6 is significantly excited during collision, while the helicopter mode excitation is negligible on a flat MG surface.

Journal Article↗
PubMed2005

GGC and StuI polymorphism on the androgen receptor gene in endometrial cancer patients.

Androgens have an anti-proliferative effect on endometrial cells. Human androgen receptor (AR) gene contains two polymorphic short tandem repeats of GGC and CAG, and a single-nucleotide polymorphism on exon 1 that is recognized by the restriction enzyme, StuI. Prior studies have shown that the lengths of the CAG repeat are inversely and linearly related to AR activity and associated with endometrial cancer. However, little is known about the GGC repeat and the StuI polymorphism of the AR gene. Thus, we investigated whether these AR polymorphisms are risk factors for endometrial cancer. To test this hypothesis, the genetic distributions of these polymorphisms were investigated in blood samples from endometrial cancer patients and healthy controls. The allelic and genotyping profiles were analyzed by polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism (PCR-RFLP), and direct DNA sequencing, and analyzed statistically. The GGC repeat was significantly longer in endometrial cancer patients as compared to normal healthy controls. In general, an increased risk of endometrial cancer was found with increasing GGC repeat. The relative risk for the 17 GGC repeat was greater than 4, as compared to controls. However, the StuI polymorphism was not significantly different between patients and controls. The findings suggest that increased numbers of GGC repeat on the AR gene may be a risk factor for endometrial cancer.

Adult↗
PubMed2005

Development of a novel serum-free freezing medium for mammalian cells using the silk protein sericin.

Cryopreservation is a pivotal process in cellular engineering for creating a continuous source of generated functional cell lines and for the convenience of various medical treatments that involve cell culture. FBS (fetal bovine serum) supplemented with 10% (v/v) DMSO is extensively used as a freezing medium for mammalian cells using conventional methods. However, FBS should ideally be avoided, owing to serious concerns regarding bovine spongiform encephalopathy and other infections such as viruses, and an alternative to FBS is eagerly awaited. Furthermore, bio-medicines and cells for transplantation should not be infectious. The present study aimed to develop a novel serum-free freezing medium. For this purpose, we focused on using the silk protein sericin as a cryoprotectant for storage and developed a novel serum-free freezing medium consisting of PBS, 1% (v/w) sericin, 0.5% (v/w) maltose, 0.3% (v/w) proline, 0.3% (v/w) glutamine and 10% DMSO. This novel freezing medium was compared with the conventional FBS supplemented with DMSO and also with three purchased freezing media with respect to cryopreservation of the P 3 U1 myeloma cell line and Chinese-hamster ovary cells. As a result, the constructed medium containing sericin successfully cryopreserved both cell types as efficiently as the conventional medium of FBS containing 10% DMSO and was superior to all three of the purchased media. The constructed medium containing sericin also cryopreserved normal human dermal fibroblasts, human epidermal keratinocytes, the rat phaeochromocytoma cell line PC12 and insect (Spodoptera frugiperda) cell line S f 9 as effectively as the conventional medium of FBS and DMSO.

Animals↗
PubMed2005

Preparation of silk protein sericin as mitogenic factor for better mammalian cell culture.

We previously reported that sericin small (sericin-S), with a molecular weight that ranges from 5 to 100 kDa, is a cell culture supplement used to accelerate cell proliferation. In this study, a novel preparation method for sericin and several applications of sericin were examined. Sericin large, prepared under nonhydrolyzing conditions and ranging from 50 to 200 kDa, also accelerated cell proliferation, but its effects were inferior to those of sericin-S. Additional sericin preparations with various molecular weights that were differentially hydrolyzed were also tested but none of them was significantly superior to sericin-S, and neither were several recombinant sericin peptides. Sericin-S successfully accelerated the proliferation of hybridoma cells in various serum-free media, implying the mitogenic effect of sericin is independent from media. We also demonstrated that sericin-S successfully induced the proliferation of CTLL-2, an established T lymphocyte cell line, under IL-2 starvation conditions. These results indicate that sericin, particularly sericin-S, improves serum-free mammalian cell culture.

Animals↗
PubMed2005

Detectability of hypometabolic regions in mild Alzheimer disease: function of time after the injection of 2-[fluorine 18]-fluoro-2-deoxy-D-glucose.

BACKGROUND AND PURPOSE: 2-[Fluorine 18]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) has played an important role in detecting hypometabolic regions in the brains of patients with dementia. To our knowledge, the optimal imaging time for dementia has not been investigated. The aim of this study was to evaluate the sensitivity of the early scanning (ES) compared with late scanning (LS) for demonstrating decreased regional glucose metabolism in patients with Alzheimer disease (AD). METHODS: Twenty patients with mild AD (mean age +/- standard deviation, 64.8 +/- 5.2 years) and 20 age- and sex-matched healthy volunteers (age, 65.9 +/- 4.5 years) were underwent FDG PET. Their cerebral glucose metabolic images were obtained on ES at 30-42 minutes and LS at 60-72 minutes after the administration of FDG 185-346 MBq. We compared regional cerebral metabolic images in a voxel-by-voxel analysis with statistical parametric mapping between patients with AD and control subjects and evaluated the difference in the hypometabolic regions between the two scans. RESULTS: In the AD-to-healthy comparison, LS at the P < .001 level of significance showed more extensive and significant hypometabolic areas than did ES. CONCLUSION: These results indicate that LS is superior to ES in detecting hypometabolic regions in patients with AD. For patients with AD, emission scanning soon after the administration of FDG is probably not advised.

Aged↗
PubMed2004

Human papilloma virus type 16 infection and the early onset of cervical cancer.

Human papilloma viruses (HPV), particularly type 16, have been associated with cervical cancer. It has been noted that the average onset of cervical cancer is occurring in younger women coupled with a higher prevalence of cervical HPV infection. However, the correlation between HPV 16 infection and the early onset of cervical cancer is still unclear. We hypothesize that HPV infection is an indicator of early onset of cervical cancer. To test this hypothesis, cervical smears from 197 women were evaluated by the polymerase chain reaction for HPV 16. These data revealed that the HPV 16-positive women were significantly younger than the HPV 16-negative women. Moreover, the average age of HPV 16-positive women with CIN 3 or invasive cancer was significantly younger compared with the other groups. These data clearly suggest that HPV 16 infection is a significant risk factor for the progression for cervical cancer in a young population of women.

Adult↗
PubMed2004

Distribution of a single nucleotide polymorphism on codon 211 of the androgen receptor gene and its correlation with human renal cell cancer in Japanese patients.

The human androgen receptor (AR) gene contains a single nucleotide polymorphism (SNP) on codon 211 and two polymorphic short tandem repeats of CAG and GGC in the N-terminal domain that may influence transcription efficiency of AR gene. We previously reported that the lengths of the CAG and GGC repeats are inversely and linearly related to AR activity and associated with several cancers. However, little is known about this SNP on codon 211 of the AR gene in human renal cell cancer. The cause of renal cell cancer is not well understood although several factors such as chemical carcinogens and hormones have been implicated. AR has been identified in human and animal renal cell cancer. We hypothesize that the SNP on codon 211 is associated with human renal cell cancer. To test this hypothesis, the genetic distribution of the SNP on codon 211 of AR gene was investigated in renal cell cancer patients (211 cases) and healthy controls (200 cases). The allelic and genotypic distributions were determined by PCR-RFLP and direct DNA sequencing techniques. The chi2 test for these data revealed that the distribution of this SNP was not different between renal cell cancer patients as compared to normal healthy controls. The findings suggest that the SNP on codon 211 in the AR gene may not have an important role in the carcinogenesis of human renal cell cancers.

Adult↗
PubMed2004

Expression and methylation status of 14-3-3 sigma gene can characterize the different histological features of ovarian cancer.

We hypothesize that 14-3-3 sigma gene expression and its regulation by methylation can characterize histological types of primary human epithelial ovarian cancer. To test this hypothesis, ovarian cancer cell lines and 54 ovarian cancer tissue samples were analyzed for expression and methylation of 14-3-3 sigma gene using methylation specific PCR. The results of our experiments demonstrate that 14-3-3 sigma gene was methylated and inactivated in ES-2 ovarian cell line, which was derived from clear cell adenocarcinoma. Treatment of this cell line with demethylating agent 5-aza-2'-deoxycytidine restored the expression of 14-3-3 sigma gene. In human ovarian cancer tissues, the expression of 14-3-3 sigma protein was inactivated in most of the ovarian clear cell carcinoma tissues. Interestingly, 14-3-3 sigma protein expression was positive in significantly higher percentages of serous (89.5%), endometrioid (90%), and mucinous (81.8%) ovarian adenocarcinoma tissues. The ovarian clear cell carcinoma samples with inactivated 14-3-3 sigma protein were highly methylated, suggesting that inactivation of 14-3-3 sigma gene is through DNA methylation. Using direct DNA sequencing, 14-3-3 sigma gene methylation on all the 17 CpG sites was significantly higher in ovarian clear cell carcinoma as compared to other histological types of ovarian cancer (serous, endometrioid, and mucinous). This is the first report suggesting that 14-3-3 sigma gene expression and methylation status can characterize histological features of different types of ovarian cancer.

14-3-3 Proteins↗
PubMed2004

Polymorphisms of the CYP1B1 gene as risk factors for human renal cell cancer.

PURPOSE: CYP1B1 activates various environmental carcinogens in human tissues, including renal tissues. We hypothesize that certain polymorphisms of the CYP1B1 gene are risk factors for renal cell cancer. The rationale for this hypothesis is that chemical procarcinogenic compounds require metabolic activation by oxidative enzymes such as CYP1B1 to be transformed into potentially carcinogenic forms. To test this hypothesis, we investigated the genotypic distributions of six different loci on the CYP1B1 gene and their association with renal cell cancer. EXPERIMENTAL DESIGN: DNA from 211 cases of human renal cell cancer and 200 healthy controls was analyzed by sequence-specific PCR and direct DNA sequencing to determine the genotypic frequencies of six different polymorphic loci on the CYP1B1 gene. RESULTS: The results of this study demonstrate that the frequencies of genotype 119T/T and genotype 432G/G were significantly higher in renal cell cancer patients compared with healthy normal controls. The relative risks were calculated as 3.01 and 2.17 for genotypes 119T/T and 432G/G, respectively, in renal cell carcinoma patients. These genotypic distributions were also significantly different between male and female patients. The relative risks of genotype 119T/T were calculated as 3.95 in males and 1.92 in females, and the relative risks of genotype 432G/G were calculated as 2.81 in males and 1.35 in females. CONCLUSIONS: The present study demonstrates for the first time that the polymorphisms at codons 119 and 432 may be risk factors for renal cancer, especially in the male population.

Aryl Hydrocarbon Hydroxylases↗
PubMed2004

Improvement of islet culture with sericin.

Islet transplantation is a promising treatment for diabetes. Serum is a necessary supplement in islet cultures, but it has various disadvantages including the risk of contamination by several pathogens. Results of this study suggest that sericin is a useful alternative supplement. Sericin accelerated the proliferation of the rat insulinoma cell line RIN-5F and improved the serum-free culture of rat islets.

Journal Article↗