Biomedical subjects

Takuya Nishioka

Publications and source records attributed to Takuya Nishioka.

4 recordsLinked to original sources

PubMed2006

Application of a lanthanide fluorescent chelate label for detection of single-nucleotide mutations with peptide nucleic acid probes.

We developed the approach to detect single-nucleotide mutation with peptide nucleic acid (PNA) probes and time-resolved fluorometry using a fluorescence lanthanide chelate label, {2,2',2'',2'''-{4'-{[(4,6-dichloro-1,3,5-triazin-2-yl)amino]biphenyl-4-yl}-2,2': 6',2''-terpyridine-6,6''-diyl}bis(methylenenitrilo)}tetrakis(acetato)}europium(III) (DTBTA-Eu3+). Compared with DNA probes, PNA probes showed lower mismatch signals and gave higher signal/noise (S/N) ratios. Using the system, we examined the single-nucleotide mutations of codon 12 in the c-Ha-ras gene of PCR amplicons of genome DNAs isolated from human umbilical vein endothelial cells (HUVECs) and T24 cells.

Base Sequence↗

PubMed2006

New luminescent europium(III) chelates for DNA labeling.

The new europium(III) chelate [2,2',2'',2'''-[[4'-(aminobiphenyl-4-yl)-2,2':6',2''-terpyridine- 6,6''-diyl]bis(methylenenitrilo)]tetrakis(acetato)] europium(III) (ATBTA-Eu3+) and its 4,6-dichloro-1,3,5-triazinyl and succinimidyl derivatives (DTBTA and NHS-ATBTA, respectively) were synthesized and characterized. Both labeling complexes DTBTA-Eu3+ and NHS-ATBTA-Eu3+ are luminescent. Especially DTBTA-Eu3+ is strongly luminescent, with a luminescence quantum yield of 9.1%, molar extinction coefficient of 3.1 x 10(4) cm(-1) M(-1) (335 nm), and luminescence lifetime of 1.02 ms. The excitation and emission maximum wavelengths of DTBTA-Eu3+ are 335 and 616 nm, respectively. The complex is very stable in aqueous buffers, with a conditional formation constant log K(DTBTA-Eu) of 25.0 at pH 8, and can be conjugated to DNA and proteins. The chelates are also highly resistant to thermal decomposition, photodegradation, and ozone oxidation. These properties prove that DTBTA-Eu3+ is suitable as a luminescence label in DNA assays.

Chelating Agents↗

PubMed2005

Detection of various platelet-associated immunoglobulins by flow cytometry in idiopathic thrombocytopenic purpura.

BACKGROUND: In 1975, Dixson reported that anti-platelet IgG on platelets from patients with idiopathic thrombocytopenic purpura (ITP) is greater than in normal people, by determining anti-platelet antibodies directly on the platelet surface with a quantitative complement lysis-inhibition-assay. Since then, platelet-associated IgG (PAIgG) has been thought of as evidence of ITP. Although platelets from ITP patients show significantly higher PAIgG values than from normal control individuals, PAIgG is not specific for autoantibody because it increases in other than immune ITP patients. METHODS: We analyzed positive platelet percentage with various platelet-associated immunoglobulins: IgG, IgM, IgA, and total immunoglobulins, in the blood from 17 normal donors and 23 ITP patients. RESULTS: The specificity for ITP disease was better in flow cytometry than in ELISA, because, other than ITP, only aplastic anemia was positive in flow cytometry; however, various disorders (aplastic anemia, chronic lymphocytic leukemia, acute myeloid leukemia, and myelodysplastic syndrome) showed positive in ELISA. Flow cytometry methods had the same sensitivity for ITP disease as ELISA. However, it is supposed that there was no nonimmune ITP in this study because the PAIgG negative patients (n = 1) showed positive results in flow cytometry. CONCLUSION: Flow cytometry method was effective for ITP screening, especially for specificity.

Adult↗

PubMed2002

Tissue factor pathway inhibitor can interact with platelets.

Tissue factor pathway inhibitor (TFPI) regulates the extrinsic pathway of blood coagulation. However, there is no report on interaction between TFPI and platelets other than that by Tsuji, who found that whole blood anticoagulated with TFPI exhibited remarkable decrease in platelet count. Our study revealed that washed platelets suspended in modified Tyrode's buffer (8 mM CaCl2) containing TFPI exhibit platelet aggregation. However, platelets aggregation was observed without TFPI, but its increase and intensity were slow and weak, compared to that in the presence of TFPI. This aggregation was inhibited by anti-CD41 (anti-GPIIb) antibody. This finding suggested that TFPI promotes platelet aggregation.

Antibodies, Monoclonal↗