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Biomedical subjects

Tatsuya Suzuki

Publications and source records attributed to Tatsuya Suzuki.

At least 19 recordsLinked to original sources
PubMed2007

Sensitive detection of estrogenic mycotoxin zearalenone by open sandwich immunoassay.

Zearalenone (ZEA) is an estrogenic mycotoxin produced by Fusarium sp., and its production on corn and small grains during storage has been of considerable concern. For sensitive ZEA detection, we applied an open sandwich (OS) immunoassay that can noncompetitively detect monovalent antigens utilizing an antigen-induced enhancement of the V(H)/V(L) interaction. We cloned the V(H) and V(L) cDNAs of anti-ZEA mAb to a split-Fv phagemid pKST2, and firstly both V(H) and V(L) fragments were displayed on M13 phage p9 and p7, respectively, using an amber suppressor, TG-1, as a host. The split-Fv phage showed specific binding to immobilized ZEA, which was well inhibited by free ZEA. Then, the V(H)/V(L) interaction and its antigen-dependency were analyzed using a non-suppressor HB2151 as a host to produce V(H)-displaying phage and his/myc-tagged soluble V(L) in the culture supernatant. By capturing V(L) with an anti-myc or -his antibody and probing bound V(H)-phage, ZEA was successfully detected with a superior detection limit as well as a wider working range than those of a competitive assay. Also, essentially the same results were reproduced with purified V(H)-alkaline phosphatase and MBP-V(L) fusion proteins.

Amino Acid Sequence↗
PubMed2006

Chromatographic zinc isotope separation by phenol formaldehyde benzo crown resin.

New types of phenol formaldehyde resin having benzo crown as a functional group were synthesized and applied to zinc isotope chromatographic operation. Zinc adsorption and isotope separation capacities were dramatically improved by using phenol formaldehyde benzo-15-crown-5 resin. Zinc batch adsorption tests were performed by various dehydrated organic solvents. Separation coefficient, epsilon 8.1 x 10(-4) and height equivalent to a theoretical plate (HETP) 0.105 cm for the isotopic pair of 68Zn/64Zn in phenol formaldehyde benzo-15-crown-5 resin were obtained in the case of acetone as the solvent at 298+/-1K.

Adsorption↗
PubMed2006

Gender-related differences in expression and function of hepatic P-glycoprotein and multidrug resistance-associated protein (Mrp2) in rats.

To clarify whether gender-related differences exist in the expression and function of hepatic P-glycoprotein- and/or multidrug resistance-associated protein (Mrp2), we measured the hepatobiliary excretion of doxorubicin and their protein levels in male and female Sprague-Dawley rats. When rats received a single intravenous injection of doxorubicin (5 mg/kg), a delay in the disappearance of doxorubicin from plasma was observed in male rats. When rats received a constant-rate infusion of doxorubicin, no significant gender-related differences in the apparent biliary clearance of doxorubicin based on the steady state plasma concentrations were observed between male and female rats. However, the net biliary clearance of doxorubicin based on the liver concentration, which represents the actual function of P-glycoprotein and/or Mrp2, was higher in female rats than in male rats. These results suggest that the actual function of the hepatobiliary transport of doxorubicin is greater in female than in male rats. Western blot analysis revealed that the expression of P-glycoprotein and Mrp2 in the liver of female rats was significantly higher than in male rats, similar to results of hepatobiliary excretion experiments. The expression of hepatic cytochrome P450 (CYP) 2B1, which is involved in the metabolism of doxorubicin, was significantly higher in male than in female rats. By pretreatment with testosterone (10 mg/day for 7 days), the actual biliary clearance of doxorubicin in female rats was nearly that of male rats. The protein levels of P-glycoprotein and Mrp2 in female rats were also lowered by treatment with testosterone so as to be nearer those in male rats. These results suggest that gender-related differences exist in P-glycoprotein- and Mrp2-mediated hepatobiliary transport and that these two transporters may be regulated by sex hormones.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2006

Nucleophosmin: a versatile molecule associated with hematological malignancies.

Nucleophosmin (NPM) is a nucleolar phosphoprotein that plays multiple roles in ribosome assembly and transport, cytoplasmic-nuclear trafficking, centrosome duplication and regulation of p53. In hematological malignancies, the NPM1 gene is frequently involved in chromosomal translocation, mutation and deletion. The NPM1 gene on 5q35 is translocated with the anaplastic lymphoma kinase (ALK) gene in anaplastic large cell lymphoma with t(2;5). The MLF1 and RARA genes are fused with NPM1 in myelodysplastic syndrome and acute myeloid leukemia (AML) with t(3;5) and acute promyelocytic leukemia with t(5;17), respectively. In each fused protein, the N-terminal NPM portion is associated with oligomerization of a partner protein leading to altered signal transduction or transcription. Recently, mutations of exon 12 have been found in a significant proportion of de novo AML, especially in those with a normal karyotype. Mutant NPM is localized aberrantly in the cytoplasm, but the molecular mechanisms for leukemia remain to be studied. Studies of knock-out mice have revealed new aspects regarding NPM1 as a tumor-suppressor gene. This review focuses on the clinical significance of the NPM1 gene in hematological malignancies and newly discovered roles of NPM associated with oncogenesis.

Animals↗
PubMed2006

Blood glucose-lowering activity of colestimide in patients with type 2 diabetes and hypercholesterolemia: a case-control study comparing colestimide with acarbose.

BACKGROUND: An anion exchange resin has been reported to lower blood glucose levels in patients with type 2 diabetes. AIM: To examine, in comparison with an alpha-glucosidase inhibitor, the usefulness of colestimide in lowering blood glucose levels in patients with type 2 diabetes and hypercholesterolemia. METHODS: Thirty-three patients with type 2 diabetes and hypercholesterolemia were more or less randomly assigned to receive either colestimide (17 patients) or acarbose (16 patients). At 10 time points before and after administration, plasma glucose levels and serum lipid concentrations were measured in all subjects, and the J-index and M-value were calculated. RESULTS: Patients receiving colestimide showed significant decreases in glucose levels 2 hours after breakfast (from 216.9 +/- 37.2 mg/dl before treatment to 191.1 +/- 40.9 mg/dl after treatment; p=0.008), in the J-index (from 42.6 +/- 14.5 to 32.6 +/- 9.8; p<0.001), and in the M-value (from 23.1 +/- 12.1 to 14.6 +/- 7.1; p<0.001). CONCLUSION: In patients with type 2 diabetes and hyperlipidemia, colestimide was suggested to have blood glucose-lowering activity as does acarbose.

Acarbose↗
PubMed2006

[Laboratory-performance study of quantitative PCR methods to analyze an approved genetically modified maize (Mon810 Line)].

A laboratory-performance study was carried out to investigate factors affecting the reliability of the quantitative PCR method to analyze an approved genetically modified (GM) maize (Mon810 line). Test maize powdered samples were prepared as blind samples containing a high (assigned value; 5.45%) or low (assigned value; 0.35%) concentration of the Mon810 line. After confirmation of their homogeneity, they were provided to 27 laboratories participating in the collaborative study. The data were collected from all laboratories and statistically analyzed. Two laboratories, which used a Roche LightCycler (LC), reported significantly high test values. A further examination showed that the LC method is greatly affected by the equipment itself or PCR reagents, resulting in poor repeatability. On the other hand, some laboratories, which used ABI quantitative PCR equipment, reported erroneous test values. In these laboratories, the errors appeared to have been due to inadequate quality and/or yield of DNA. To identify factors affecting the test values, analysis of the measured values for the taxon-specific gene will be useful. Furthermore, the modified silica-gel membrane DNA extraction method made it possible to extract the required amounts of DNA more easily and in a shorter time than before.

DNA, Plant↗
PubMed2005

Clinical characteristics and prognostic implications of NPM1 mutations in acute myeloid leukemia.

Recently, somatic mutations of the nucleophosmin gene (NPM1), which alter the subcellular localization of the product, have been reported in acute myeloid leukemia (AML). We analyzed the clinical significance of NPM1 mutations in comparison with cytogenetics, FLT3, NRAS, and TP53 mutations, and a partial tandem duplication of the MLL gene (MLL-TD) in 257 patients with AML. We found NPM1 mutations, including 4 novel sequence variants, in 64 of 257 (24.9%) patients. NPM1 mutations were associated with normal karyotype and with internal tandem duplication (ITD) and D835 mutations in FLT3, but not with other mutations. In 190 patients without the M3 French-American-British (FAB) subtype who were treated with the protocol of the Japan Adult Leukemia Study Group, multivariate analyses showed that the NPM1 mutation was a favorable factor for achieving complete remission but was associated with a high relapse rate. Sequential analysis using 39 paired samples obtained at diagnosis and relapse showed that NPM1 mutations were lost at relapse in 2 of the 17 patients who had NPM1 mutations at diagnosis. These results suggest that the NPM1 mutation is not necessarily an early event during leukemogenesis or that leukemia clones with NPM1 mutations are sensitive to chemotherapy.

Adolescent↗
PubMed2005

Kinetics of marked development of lung metastasis of rat prostatic carcinomas transplanted in syngeneic rats.

In order to investigate how and when metastases develop under experimental conditions, kinetics of the size and the number of lung metastasis lesions in F344 rats were examined after syngeneic transplantation of rat prostate carcinomas induced by 3,2'-dimethyl-4-aminobiphenyl (DMAB). Cell proliferation of the subcutaneous tumor and lung metastatic lesions was evaluated along with the expression of VEGF-A splicing variants and endostatin, serum VEGF levels and vascular density in the tumor. Several pieces of tumor tissue were introduced subcutaneously into two different sites on the dorsal side of F344 rats through a 14G needle. Average body weight of recipient rats markedly decreased despite only a gradual increase in tumor volume. The absolute total number of metastatic lesions in rats (n=5) were 2, 10, 19 and 194 at weeks 7.5, 9, 11 and 13, respectively, and a notable increase was observed at week 13. Similarly, the mitotic index of lung metastatic lesions increased remarkably at week 9 while the mitotic index and apoptotic index of transplanted tumors did not change throughout the experimental period. Expression of VEGF-A121, A164, A188 and endostatin, serum VEGF levels and vascular density did not correlate with the spread of lung lesions. In conclusion, both the number and the size of metastatic lesions increased at the same time after a notable increase in cell proliferation. Factors other than VEGF or endostatin may be involved in the mechanism of explosive lung metastasis spread.

Animals↗
PubMed2005

Variations in aganglionic segment length of the enteric neural plexus in Mowat-Wilson syndrome.

BACKGROUND/PURPOSE: Patients with zinc finger homeo box 1B (ZFHX1B) mutations or deletions develop multiple congenital anomalies including Hirschsprung disease, known as Mowat-Wilson syndrome (MWS). In this study, we investigated variations in the enteric neural plexus abnormalities in MWS using morphometry-based histopathologic analysis. METHODS: Seven patients with MWS (3 with mutations in exon 8 of ZFHX1B and 4 with deletions) who had undergone modified Duhamel's operations for Hirschsprung disease were examined. Surgically resected rectosigmoid specimens were analyzed morphometrically. RESULTS: The length of the aganglionic segment was longer than 3 cm in all the patients with deletions. In 3 patients with mutations, the aganglionic region was not detected in the surgically resected specimens; however, the parameters of the ganglions and plexus were significantly smaller than those of controls (cloaca and aproctia), indicative of a transitional zone. Variation in the severity of pathological changes among the 3 patients with mutations was also noted. CONCLUSIONS: The variations in myenteric plexus pathologies in MWS appear to be caused by both variations in ZFHX1B abnormalities and epigenetic factors.

Anthropometry↗
PubMed2005

Modeling of driver's collision avoidance maneuver based on controller switching model.

This paper presents a modeling strategy of human driving behavior based on the controller switching model focusing on the driver's collision avoidance maneuver. The driving data are collected by using the three-dimensional (3-D) driving simulator based on the CAVE Automatic Virtual Environment (CAVE), which provides stereoscopic immersive virtual environment. In our modeling, the control scenario of the human driver, that is, the mapping from the driver's sensory information to the operation of the driver such as acceleration, braking, and steering, is expressed by Piecewise Polynomial (PWP) model. Since the PWP model includes both continuous behaviors given by polynomials and discrete logical conditions, it can be regarded as a class of Hybrid Dynamical System (HDS). The identification problem for the PWP model is formulated as the Mixed Integer Linear Programming (MILP) by transforming the switching conditions into binary variables. From the obtained results, it is found that the driver appropriately switches the "control law" according to the sensory information. In addition, the driving characteristics of the beginner driver and the expert driver are compared and discussed. These results enable us to capture not only the physical meaning of the driving skill but the decision-making aspect (switching conditions) in the driver's collision avoidance maneuver as well.

Accidents, Traffic↗
PubMed2005

Serum matrix metalloproteinase and tissue inhibitor of metalloproteinase concentrations in infertile women achieved pregnancy following IVF-ET.

PROBLEM: Matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) play important roles throughout various stages of pregnancy, including embryo implantation, trophoblastic invasion, placentation in early gestation, and cervical dilatation in later gestation, and feto-maternal membrane lysis. It would be beneficial if assessment of serum concentrations of MMP and TIMP could predict successful implantation following in vitro fertilization-embryo transfer (IVF-ET). This study was performed to compare serum MMP and TIMP concentrations between patients with and without the establishment of pregnancy following ET. METHOD OF STUDY: Ten patients who conceived and 10 patients who did not after IVF-ET were entered in the present study. Only intra-uterine single pregnancies with uneventful courses to term were included in the study subjects. Blood samples were obtained at 7, 14 and 21 days after oocyte retrieval. Serum concentrations of MMP-1, MMP-2, MMP-3, and TIMP-1 were measured using enzyme-linked immunosorbent assay. These variables were compared with estradiol (E(2)), progesterone (P(4)), and betahCG levels in the patients' sera. Clinical pregnancies were diagnosed only when fetal heartbeat was visualized on ultrasound. RESULTS: There were no significant differences in serum MMP concentrations between the pregnant group and the non-pregnant group. However, serum TIMP-1 concentrations on Days 14 and 21 in the pregnant group were significantly higher than those in non-pregnant group [Day 14: 223.1 +/- 11.9 versus 177.5 +/- 20.6 ng/mL (P = 0.004); Day 21: 215.4 +/- 27.8 versus 181.5 +/- 27.4 ng/mL (P = 0.03)]. Serum TIMP-1 concentrations were also correlated with serum E(2) and P(4) levels (P < 0.0001), but not with those of the MMPs. None of MMP nor TIMP-1 were correlated with serum betahCG level. CONCLUSIONS: It was demonstrated that the patients who successfully conceived after IVF-ET showed significantly higher levels of TIMP-1 at 14 and 21 days after IVF-ET, but not at day 7; further work will be required to determine if serum TIMP-1 can be used to improve prediction of pregnancy outcome in these patients.

Adult↗
PubMed2005

[Carotid parameters measured by ultrasonography as a marker of atherothrombotic infarction and lacunar infarction in high risk elderly people].

AIM: Many studies have reported that carotid parameters measured by ultrasonography were predictors for stroke. The aim of this study was to investigate by cross-sectional study in elderly people having cardiovascular risk factors whether those carotid parameters are markers for atherothrombotic infarction (AI) and lacunar infarction (LI). METHODS: Subjects of this study were 314 patients aged 65 years or older who had controlled cardiovascular risk factors and assessed carotid artery by ultrasonography. Subjects were categorized into control, AI and LI group. Clinical characteristics (biochemical analysis, body mass index, systolic/diastolic blood pressure, smoking habits, hypertension, diabetes mellitus and statin therapy) and carotid parameters (maximum intima-media thickness (Max-IMT), plaque score (PLQ-S) and Maximum pulsatility index (Max-PI)) were compared among three groups. RESULTS: PLQ-S, Max-PI, frequency of PLQ-S > or = 10mm and frequency of Max-PI > or = 2.0 in the AI group were significantly higher than in the control group. There were no significant differences between control and LI group concerning those carotid parameters. Multivariate logistic regression analysis showed that there were significant correlations between AI and PLQ-S > or = 10mm (odds ratio 2.980; P = 0.011), AI and Max-PI > or = 2.0 (odds ratio 2.458; P = 0.038), but there was no significant correlation between those carotid parameters and LI. CONCLUSION: This study suggests that in high risk elderly people, PLQ-S and PI are better markers for AI than IMT, but those carotid parameters have poor associations with LI.

Aged↗
PubMed2005

[Laboratory performance study of the quantitative detection method for genetically modified soybeans (roundup ready soybeans 40-3-2)].

To investigate important factors affecting the analytical results, a laboratory-performance study was attempted for the Japanese official methods to detect genetically modified (GM) soybeans (40-3-2). Test samples containing 0, 1 and 5% GM soya powder in non-GM soya powder was prepared. A set of 3 test samples was sent to the participating laboratories along with the protocol. The data were collected from all laboratories and statistically analyzed. In the real-time PCR detection method, the average values of the GM 1% and 5% samples were both much lower than the spiked value because the laboratories using a silica-membrane DNA extraction method underestimated the GM value. On the other hand, the laboratories using other extraction methods, such as the CTAB method obtained values close to the spiked value. These results suggest that use of the silica-membrane DNA extraction method may result in underestimation of the GM content in the real-time PCR method. In the ELISA method, the average value of 5% spiked samples appears to be slightly higher than the fortified value. But, overall, it was considered that reported values were close to the spiked level.

DNA, Plant↗
PubMed2004

Effect of alcohols on elution chromatography of trivalent actinides and lanthanides using tertiary pyridine resin with hydrochloric acid-alcohol mixed solvents.

Elution chromatography with a tertiary pyridine resin has been used to separate the trivalent actinides (An3+) from the lanthanides (Ln3+) using an alcoholic hydrochloric acid solvent. Trivalent Am and Cm were separated from the Ln by employing a 1 cm(phi) x 10 cm resin column with the mixed solvent system composed of concentrated hydrochloric acid (HCl) and alcohols. The distribution coefficients (Kd) and the separation factors between An and Ln (alpha(An)(Ln)) increased as the alcohol content of the solvent mixture increased. On the other hand, the Kd and alpha(An)(Ln) decreased drastically upon the addition of water to the solvent mixture. Among the four alcohols investigated (methanol, ethanol, n-propanol and n-butanol), the ethanol-HCl mixed solvent system showed the largest Kd and alpha(An)(Ln). The mechanism of adsorption for An and Ln cations on the pyridine resin is discussed in addition to the results presented herein.

Actinoid Series Elements↗