Biomedical subjects

Atsuko Takeuchi

Publications and source records attributed to Atsuko Takeuchi.

11 recordsLinked to original sources

PubMed2006

Quantification of lysophosphatidylcholines and phosphatidylcholines using liquid chromatography-tandem mass spectrometry in neonatal serum.

We established an improved method for quantification of phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) molecular species in neonatal serum using high-performance liquid chromatography coupled tandem mass spectrometry (LC-MS/MS). A multiple reaction monitoring (MRM) mode of positive ionization for MS/MS was used. The method involved purification of phospholipids by solid phase extraction (SPE) from a 20-microl minimum specimen of serum. The assayed values of authentic 16:0-LPC and 18:0-LPC showed a linear response, and our quantitative results showed high precision for the all species of PC and LPC. Then, we quantified PC and LPC in adult and neonatal serum and compared them. Day 0-1 neonatal serum 16:0-, 18:0-, 18:1-, 18:2-LPC levels were significantly lower than adult ones. All species LPC levels in the day 0-1 neonates were significantly lower than day 4-8 neonates. Day 0-1 neonatal serum 16:0/18:2-, 18:0/18:2-PC levels were significantly lower than adult ones. Our method is advantageous for precise assessments of the relationships between PCs/LPCs levels and neonatal infectious diseases.

Adult↗

PubMed2006

Evaluation of mutation effects on UGT1A1 activity toward 17beta-estradiol using liquid chromatography-tandem mass spectrometry.

Mutations in the gene encoding UDP-glucuronosyltransferase 1A1 (UGT1A1) may reduce the glucuronidation of estradiol, bilirubin, etc. In the present study, we used a liquid chromatography-tandem mass spectrometry (LC/MS/MS) method to assay the activities of recombinant mutated UGT1A1 toward 17beta-estradiol (E2), by determining its glucuronide (E2G) content. Direct evidence for glucuronide formation was provided by E2G-specific ion peaks. The UGT1A1 activities of G71R (exon 1), F83L (exon 1), I322V (exon 2) and G493R (exon 5) mutants were 24, 30, 18 and 0.6% of the normal UGT1A1 activity, respectively. In conclusion, our study showed that LC/MS/MS enabled accurate evaluation of the effects of mutations on recombinant UGT1A1 activity towards E2.

Animals↗

PubMed2005

Comparison of neurocognitive results after coronary artery bypass grafting and thoracic aortic surgery using retrograde cerebral perfusion.

OBJECTIVE: Retrograde cerebral perfusion (RCP) is used as an adjunctive method to hypothermic circulatory arrest to enhance cerebral protection in patients undergoing thoracic aortic surgery. It remains unclear whether RCP provides improved neurological and neuropsychological outcome. METHODS: Forty-six patients undergoing thoracic aortic surgery using RCP, and 28 undergoing coronary artery bypass grafting (CABG; n = 28) with CPB, were enrolled in the study. Patients receiving RCP were subdivided into two groups, those with less than 60 min of RCP (S-RCP; n = 27) and with 60 min or more (L-RCP; n = 19). The patients' neurocognitive state was assessed by the revised Wechsler Adult Intelligence Scale a few days before operation, at 2-3 weeks and 4-6 months after operation. RESULTS: There were no stroke, seizure, and hospital mortality in either group. Significant decline between baseline and early scores were seen in three subtests (digit span, arithmetic, and picture completion) for S-RCP and four (digit span, arithmetic, picture completion, and picture arrangement) for L-RCP. Significant decline between baseline and late scores were seen in one subtest (arithmetic) for S-RCP, four (digit span, arithmetic, picture completion, and picture arrangement) for L-RCP, and one (object assembly) for CABG. The mean change of scores for one late test (digit symbol) was significantly lower in S-RCP than in CABG. The mean change of scores for three early tests (digit span, vocabulary, and picture arrangement) and four late tests (information, digit span, picture completion, and picture arrangement) were significantly lower in L-RCP than in CABG. Stepwise logistic regression analysis disclosed that, after considering the other variables, significant difference in test score changes were observed between CABG and L-RCP for two early tests (picture completion and digit symbol) as well as for three late tests (digit span, similarities, and picture completion). None of test score changes showed significant difference between CABG and S-RCP. CONCLUSIONS: The neurocognitive outcome in patients undergoing RCP less than 60 min were comparable with patients undergoing CABG without circulatory arrest. Prolonged RCP of 60 min or more in patients undergoing surgery of the thoracic aorta was associated with postoperative neurocognitive impairment.

Adult↗

PubMed2005

Structural analyses of metabolites of phenolic 1-benzyltetrahydroisoquinolines in plant cell cultures by LC/NMR, LC/MS, and LC/CD.

The metabolism of the phenolic 1-benzyltetrahydroisoquinoline alkaloids was studied in cell cultures of Macleaya and Corydalis species. The crude alkaloid fraction obtained from feeding experiments was investigated by application of the combined LC/NMR and LC/APCI-MS (/MS) techniques. Several metabolites were detected, and their structures (6 and 8-14) were identified. Bioconversion of the phenolic 1-benzyltetrahydroisoquinoline (2) into the pseudoprotoberberine (8) was demonstrated for the first time. LC/APCI-MS and LC/CD experiments carried out on a chiral column permitted the deduction of the major enantiomeric form of the chiral metabolites. Thus, the combination of NMR, MS, and CD data permitted the structural elucidation and stereochemical analysis of the metabolites in the extract matrix solution, without isolation and sample purification prior to the coupling experiments.

Cells, Cultured↗

PubMed2004

Neurocognitive outcome after retrograde cerebral perfusion.

BACKGROUND: Neurocognitive outcome in patients undergoing thoracic aortic surgery using retrograde cerebral perfusion (RCP) remains uncertain. METHODS: Forty-two patients undergoing thoracic aortic surgery using RCP were enrolled in the study. The patients' neurocognitive state was assessed by the revised Wechsler Adult Intelligence Scale (WAIS-R) a few days before operation, at 2 to 3 weeks, and at 4 to 6 months after operation. RESULTS: There were no stroke, seizure, and hospital death. Significant performance deterioration was observed in digit span, arithmetic, and picture completion of the WAIS-R subtests. Bivariate comparison showed that older age (late vocabulary, late similarities, and late object assembly), longer RCP time (early picture arrangement, and early block design), later awake time (early and late picture arrangement, and early block design), longer respirator use (early and late digit span, late picture arrangement), longer ICU time (late picture completion, early and late picture arrangement, and early block design), and longer hospital stay (early picture arrangement) were significantly associated with the decline in neurocognitive performance. Stepwise logistic regression analysis disclosed that older age (late similarities and late object assembly), later awake time (late picture arrangement), and longer respirator use (early and late digit span, and late picture arrangement) were most predictive for the decline in neurocognitive performance. CONCLUSIONS: On average, digit span, arithmetic, and picture completion tests were most sensitive in detecting the decline in neurocognitive performance. The relationship between the duration of RCP and neurocognitive test results was not significant.

Aged↗

PubMed2004

[5'-nucleotidase].

Explore the source record for details and available documents.

5'-Nucleotidase↗

PubMed2003

Protein 4.1-mediated membrane targeting of human discs large in epithelial cells.

Human discs large (hDlg) protein binds to protein 4.1R via a motif encoded by an alternatively spliced exon located between the SH3 and the C-terminal guanylate kinase-like domains. To evaluate the functional significance of protein 4.1R binding for subcellular localization of hDlg in vivo, we expressed full-length recombinant constructs of two naturally occurring isoforms of hDlg termed hDlg-I2 and hDlg-I3. The hDlg-I3 but not the hDlg-I2 isoform binds to the FERM (Four.1-Ezrin-Radixin-Moesin) domain of protein 4.1R in vitro. Upon transient transfection into subconfluent Madine-Darby canine kidney (MDCK) epithelial cells, the hDlg-I3 fused with the green fluorescent protein accumulated predominantly at the plasma membrane of cell-cell contact sites, whereas the hDlg-I2 fusion protein distributed in the cytoplasm. In contrast, in stably transfected confluent MDCK cells, both hDlg-I2 and -I3 isoforms localized efficiently to the lateral membrane, consistent with the previous notion that the N-terminal domain of hDlg mediates its membrane targeting in polarized epithelial cells. We introduced a double mutation (I38A/I40A) into the N-terminal domain of hDlg, which disrupted its interaction with DLG2, a key event in the membrane targeting of hDlg. Interestingly, the hDlg-I2 isoform harboring the I38A/I40A mutation mislocalized from the membrane into cytoplasm. Importantly, the hDlg-I3 isoform with the same mutation localized efficiently to the membrane of confluent MDCK cells. Together, our results demonstrate that in addition to the N-terminal targeting domain, the alternatively spliced I3 insertion plays a critical role in recruiting hDlg to the lateral membrane in epithelial cells via its interaction with protein 4.1R.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Severe chronic active Epstein-Barr virus infection associated with multiple necrotic lesions in the liver.

We report an atypical presentation of a chronic active Epstein-Barr virus (EBV) infection with multiple nodular coagulation necrosis in the liver, that appeared as hypodense areas on a CT scan. The patient, a 26-year-old man, was hospitalized following over 2 years of intermittent fever, weight loss and liver abnormalities after contracting infectious mononucleosis. We diagnosed his illness as a chronic active EBV infection (CAEBV) because of the high antibody titers against EBV and the histological evidence of organ disease with demonstration of EBV mRNA. A liver biopsy revealed EBV-infected T-cell infiltration with hemophagocytosis and marked hepatocytolytic necrosis. The patient developed multiple coagulation necrosis with well-defined borders surrounding T-cell aggregation in the liver 8 months later. He died of respiratory failure due to interstitial pneumonitis. The analysis of EBV-genome termini demonstrated a clonal proliferation of T-cells harboring EBV, but no T-cell antigen receptor (TCR) gene rearrangement was observed. We speculate that the pathogenesis of this disease was an atypical expression of organ damage as a result of an aberrant T-cell response to EBV infection.

Journal Article↗

PubMed2003

Inhibition of ileal bile acid absorption by colestimide.

BACKGROUND: Colestimide is a new type of anion-exchange resin in Japan, but its effect on bile acid absorption in the ileum has not been studied. METHODS: Absorption of ursodeoxycholate, tauroursodeoxycholate, cholate, taurocholate and taurolithocholate-sulfate in rat ileum was compared in the presence and absence of colestimide. Bile acid adsorption by colestimide in vitro was also studied. RESULTS: All bile acids were efficiently absorbed by the ileum, and the cumulative absorption during 60 min was 25-78%. The absorption of ursodeoxycholate, tauroursodeoxycholate and taurocholate was inhibited by colestimide, whereas that of cholate and taurolithocholate-sulfate was not inhibited by colestimide. Adsorption of bile acids by colestimide in vitro was higher with taurine conjugates than with the unconjugated forms. CONCLUSIONS: Colestimide was shown to be useful to inhibit the physiologically important ileal absorption of bile acid amides in vivo.

Animals↗

PubMed2003

[Dietary intakes of vitamin D and calcium in Japanese].

According to the National Nutrition Survey in Japan, 2001 by Ministry of Health, Labour and Welfare, Japan, the average intakes of vitamin D, phosphorus and magnesium in Japanese have met their RDA values except for calcium. For the elderly women, calcium stands first among the nutrients that they want to intake from functional foods.

English Abstract↗

PubMed2002

Direct interaction with a kinesin-related motor mediates transport of mammalian discs large tumor suppressor homologue in epithelial cells.

Membrane-associated guanylate kinase homologues (MAGUKs) are generally found under the plasma membrane of cell-cell contact sites and function as scaffolding proteins by linking cytoskeletal and signaling molecules to transmembrane receptors. The correct targeting of MAGUKs is essential for their receptor-clustering function; however, the molecular mechanism of their intracellular transport is unknown. Here, we show that the guanylate kinase-like domain of human discs large protein binds directly within the amino acids 607-831 of the stalk domain of GAKIN, a kinesin-like protein of broad distribution. The primary structure of the binding segment, termed MAGUK binding stalk domain, is conserved in Drosophila kinesin-73 and some other motor and non-motor proteins. This stalk segment is not found in GKAP, a synaptic protein that interacts with the guanylate kinase-like domain, and unlike GKAP, the binding of GAKIN is not regulated by the intramolecular interactions within the discs large protein. The recombinant motor domain of GAKIN is an active microtubule-stimulated ATPase with k(cat) = 45 s(-1), K(0.5 (MT)) = 0.1 microm. Overexpression of green fluorescent protein-fused GAKIN in Madin-Darby canine kidney epithelial cells induced long projections with both GAKIN and endogenous discs large accumulating at the tip of these projections. Importantly, the accumulation of endogenous discs large was eliminated when a mutant GAKIN lacking its motor domain was overexpressed under similar conditions. Taken together, our results indicate that discs large is a cargo molecule of GAKIN and suggest a mechanism for intracellular trafficking of MAGUK-laden vesicles to specialized membrane sites in mammalian cells.

Adenosine Triphosphatases↗