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Biomedical subjects

Y Aoyagi

Publications and source records attributed to Y Aoyagi.

At least 55 records · Page 3Linked to original sources
PubMed2000

Plasma fucosyltransferase activity in patients with hepatocellular carcinoma, with special reference to correlation with fucosylated species of alpha-fetoprotein.

BACKGROUND/AIMS: Our previous results showed that the percentage of fucosylated species of alpha-fetoprotein (AFP) in total AFP, fucosylation index, was a very useful diagnostic tool to distinguish AFP due to hepatocellular carcinoma from AFP due to non-neoplastic liver diseases. On the other hand, alpha1-6 fucosyl-transferase (alphaFT) catalyzes the addition of fucose from GDP-fucose through an alpha1-6 linkage to the reducing end of N-acetylglucosamine residue of N-linked oligosaccharides of glycoproteins. However, the biological and clinical significance of alphaFT in patients with hepatocellular carcinoma is not fully understood. In the present study, we measured alphaFT activity to elucidate the enzymatic background of fucosylated species of AFP in hepatocellular carcinoma. METHODS: Plasma samples from 84 cases of hepatocellular carcinoma, 40 of liver cirrhosis, 40 of chronic hepatitis and 30 of normal controls, and 26 paired samples of hepatocellular carcinoma and surrounding noncancerous tissues were enrolled in the present study. AlphaFT activity was measured by high performance liquid chromatography with a synthesized fluorescence-labeled glycopeptide with an asialoagalactobiantennary sugar chain as a substrate in the presence of GDP-fucose. RESULTS: Plasma alphaFT activities (mean+/-SD, pmol/ml/h) in patients with hepatocellular carcinoma, liver cirrhosis, chronic hepatitis and normal controls were 435+/-271, 490+/-290, 590+/-209 and 380+/-133, respectively. AlphaFT levels in hepatocellular carcinoma and chronic liver diseases were increased compared with that in normal controls. A statistically significant positive correlation was observed between plasma alphaFT activity and fucosylation index of AFP (r=0.34, p= 0.0032) in 60 patients with hepatocellular carcinoma, in which increments of serum AFP were observed. When the tentative cutoff value of fucosylation index was set at 18%, which corresponded to the cutoff value to discriminate between hepatocellular carcinoma and non-neoplastic liver diseases in our previous study, the plasma alphaFT activity in hepatocellular carcinoma patients whose fucosylation index was more than 18% (n=32, 523+/-324 pmol/ml/h) was higher than that in hepatocellular carcinoma patients whose fucosylation index was equal to or less than 18% (n=28, 383+/-229) (p=0.055). An increment of the plasma levels of alphaFT occurred in accordance with an advancement of hepatocellular carcinoma stages. Tissue aFT activity in hepatocellular carcinoma (175+/-178 pmol/mg/h) was higher than those in surrounding noncancerous liver (144+/-134) and in normal liver (79+/-19). The mean alphaFT activities in well-, moderately- and poorly-differentiated hepatocellular carcinoma were 38+/-0.7, 177+/-182 and 219+/-189, respectively, and they tended to increase with dedifferentiation in hepatocellular carcinoma tissues. CONCLUSIONS: The present study indicates that alphaFT is responsible for the formation of the fucosylated species of AFP in hepatocellular carcinoma and suggests that the measurement of alphaFT provides a possible aid in the evaluation of the degree of advancement in patients with hepatocellular carcinoma.

Aged↗
PubMed2000

Ascorbic acid supplementation to primary culture of chicken hepatocytes with non-serum medium.

Chicken liver is lack of ascorbic acid biosynthesis system, different from mammals and highly evoluted birds. Chicken hepatocytes cultured without ascorbate was expected to have lower ascorbate amounts than physiological levels. Intracellular was decreased as compared with intact liver by cell preparation performed with in situ collagenase perfusion. We added ascorbate to a primary culture of chicken hepatocytes in order to restore the amount of ascorbate. Serum-free Leivobitz's L-15 medium which do not contain ascorbate was used for control medium. Cells were cultured with several concentrations of ascorbate for 24 or 48 h. After ascorbate supplementation for 24 to 48 h, cellular ascorbate concentration increased depending on the dose of medium ascorbate. Medium lactate dehydrogenase activity derived from hepatocytes, an index of cell injury, decreased upon 5-100 mg/l of ascorbate supplementation for 48 h. Tyrosine aminotransferase activity, an index of liver function, increased following culture with 50 and 100 mg/l ascorbate for 48 h. The activities, however, decreased by supplementation with 1000 mg/l of ascorbate. In conclusion hepatocytes lost intracellular ascorbate during preparation by in situ collagenase perfusion. Supplementation of ascorbate restored cellular ascorbate concentration, lowered cell injury and raised tyrosine aminotransferase activitv in primary cultured chicken hepatocytes. Ascorbate treatment for 48 h at 50 mg/l was the best combination in this study for primary culture of chicken hepatpcyte with non-serum L-15 medium

Animals↗
PubMed2000

Use of the collision technique to improve the accuracy of motor unit number estimation.

OBJECTIVE: To evaluate the risk of stimulating the same motor axon at different points along the median nerve when using the multiple point stimulation (MPS) technique and how this affects the accuracy of the motor unit number estimate (MUNE). METHODS: Using the MPS technique, MUNE in the median innervated intrinsic hand muscles was done on two normal subjects, a patient with carpal tunnel syndrome and one with prior poliomyelitis. The collision technique was then used to confirm whether two motor unit action potentials (MUAPs) with similar configurations and sizes were generated by the same motor unit. A new MUNE was recalculated after the repeated inclusion of the same motor unit had been excluded. RESULTS: While the risk of stimulating the same motor axon at widely separate locations of the median nerve was negligible in normal subjects, this risk was much higher in patients with a depleted motor neuron pool. This resulted in marked distortion of the calculated size of the average single MUAP and, consequently, inaccuracy of the MUNE. CONCLUSIONS: The inadvertent inclusion of the same motor units, if not recognized, can markedly affect the accuracy of the MUNE. The collision technique can be useful in minimizing this risk.

Action Potentials↗
PubMed2000

Expanded polyglutamine stretches interact with TAFII130, interfering with CREB-dependent transcription.

At least eight inherited neurodegenerative diseases are caused by expanded CAG repeats encoding polyglutamine (polyQ) stretches. Although cytotoxicities of expanded polyQ stretches are implicated, the molecular mechanisms of neurodegeneration remain unclear. We found that expanded polyQ stretches preferentially bind to TAFII130, a coactivator involved in cAMP-responsive element binding protein (CREB)-dependent transcriptional activation, and strongly suppress CREB-dependent transcriptional activation. The suppression of CREB-dependent transcription and the cell death induced by polyQ stretches were restored by the co-expression of TAFII130. Our results indicate that interference of transcription by the binding of TAFII130 with expanded polyQ stretches is involved in the pathogenetic mechanisms underlying neurodegeneration.

Aged↗
PubMed2000

Elevation of TFF1 gene expression during healing of gastric ulcer at non-ulcerated sites in the stomach: semiquantification using the single tube method of polymerase chain reaction.

BACKGROUND: The Trefoil factor family 1 (TFF1), one of the trefoil peptides, has been considered to play protective and reparative roles of experimentally induced ulcers in the stomach. However, the alteration of the TFF1 mRNA in the non-ulcerated areas of living human gastric mucosa in gastric ulcer is not well known. We examined TFF1 gene expression at non-ulcerated sites during the healing of a gastric ulcer by semiquantitative determination of the TFF1 mRNA. METHODS: Gastric mucosal biopsy specimens were taken before and after the healing of the gastric ulcer from seven consecutive patients and from seven patients diagnosed with non-ulcer dyspepsia (NUD). The relative value of TFF1 mRNA (RTFF1) was calculated by the single tube method of polymerase chain reaction (ST-PCR) and Southern hybridization. Immunohistochemistry using monoclonal antibodies was performed to confirm the presence of the TFF1 peptide. The status of Helicobacter pylori and the severity of gastritis were investigated simultaneously. RESULTS: The mean relative values of TFF1 mRNA at both the gastric angle (RTFF1AS) and the gastric body (RTFF1BS) of patients with gastric ulcers at the healed stage were significantly higher than those at the open stage (P< 0.05). The mean RTFF1AS at both the open and healed stages were lower than those of RTFF1BS at the open and healed stages, respectively, The mean RTFF1B at the open stage was lower than that in NUD (not significant), but the mean of RTFF1B at the healed stage was significantly higher than that in NUD. The RTFF1AS and RTFF1BS of all patients did not correlate with H. pylori status nor with the severity of gastritis. The induction of TFF1 mRNA at the non-ulcerated background sites seemed not to be related to the status of H. pylori or to the severity of gastritis. CONCLUSIONS: These results suggest that the increased levels TFF1 mRNA during the healing of gastric ulcers might be closely related to the protection and the cell differentiation at the non-ulcerated areas of living human gastric mucosa.

Actins↗
PubMed2000

Quantitative evaluation of genomic instability as a possible predictor for development of hepatocellular carcinoma: comparison of loss of heterozygosity and replication error.

Both loss of heterozygosity (LOH) and replication error (RER) are considered to be phenotypes of genomic instability. To unveil the role of the genomic instability in hepatocarcinogenesis, frequencies of LOH and RER were simultaneously determined in 15 hepatocellular carcinomas (HCCs), surrounding nontumorous liver tissues (SL), and 13 liver tissues with chronic viral hepatitis void of cancer (NC) by referencing peripheral blood leukocytes (PBLs) from the corresponding donor using 18 microsatellite markers spread throughout the genome. LOH was significantly frequent in HCC compared with that in SL or NC (P =.005, P =.0003, respectively) and observed preferentially at particular microsatellite loci, D1S204, D2S123, D8S1106, D9S266, D16S748, and D19S601. Although the higher prevalence of RER was also significant in HCC compared with that in NC (P =.03), in most cases the errors were detected at very low frequencies and random loci. Both LOH and RER tended to appear more prevalently in SL than in NC. The occurrence rate of LOH was higher in the tissues associated with hepatitis B virus (HBV) than with hepatitis C virus (HCV) infection especially in HCC (P =.03). When referencing SL instead of PBLs, the prevalence of LOH and RER in HCC significantly decreased (P =.02 and P =.03, respectively). These results suggest that LOH is closely associated with multistep hepatocarcinogenesis especially under HBV infection, but RER is imperceptibly associated. The quantitative evaluation of the frequency of LOH by referencing PBLs may be a useful predictor for HCC development in chronic liver diseases.

Blood Cells↗
PubMed2000

Pharmacological effects of urinary products obtained after treatment with saiboku-to, a herbal medicine for bronchial asthma, on type IV allergic reaction.

To define the anti-allergic components in Saiboku-To, a herbal medicine for bronchial asthma, we examined the effects of 11 compounds found in post-administrative urine of Saiboku-To on concanavalin A-induced human lymphocyte blastogenesis in vitro and picryl chloride (PC)-induced mouse ear swelling in vivo. The urinary products of Saiboku-To were flavonoids and lignans derived from the constitutional herbs and their hydrogenated metabolites. Medicarpin derived from Glycyrrhiza glabra, magnolol and 8,9-dihydroxydihydromagnolol from Magnolia officinalis, baicalein, wogonin and oroxylin A from Suctellaria baicalensis inhibited lymphocyte blastogenesis in dose-dependent fashion with IC50 values ranging from 3.0 to 7.7 micrograms/mL, which corresponded to 20-100 times that of prednisolone IC50 (0.08 microgram/mL). Davidigenin, dihydrowogonin and dihydrooroxylin A, which are hydrogenated metabolites of liquiritigenin, wogonin and oroxylin A, respectively, had no or little effects on lymphocyte blastogenesis. Oral administration of Saiboku-To, medicarpin, baicalein, magnolol and baicalin (100 mg/kg), inhibited PC-induced ear swelling significantly by 23.5, 40.1, 30.5, 23.6 and 20.9%, respectively, though the effects were weaker than that of 5 mg/kg of prednisolone (52.9%). The results suggested that flavonoids and lignans tested in the present study were implicated in anti-asthmatic effect of Saiboku-To through suppression of type IV allergic reaction.

Animals↗
PubMed2000

Establishment and characterization of 6-[[2-(Dimethylamino)ethyl]amino]-3-hydroxy-7H-indeno[2,1-c]quinolin-7-one dihydrochloride (TAS-103)-resistant cell lines.

6-2-(Dimethylamino)ethylămino-3-hydroxy-7H-indeno2, 1-cquinolin-7-one dihydrochloride (TAS-103) is a novel anticancer agent that was developed to target both topoisomerase (Topo) I and Topo II. To elucidate its mechanism of action, we have established and characterized TAS-103-resistant cells, derived from mouse leukemia (P388), human colon cancer (DLD-1), and human lung adenocarcinoma (A549) cell lines, by exposure to stepwisely increasing concentrations of TAS-103 in the culture medium. P388 / TAS cells showed only cross-resistance to VP-16 and adriamycin (ADR). The Topo II activity in these cells was decreased to below one-fourth of that in the parental cells, while the Topo I activity remained unchanged. DLD / TAS cells appeared to be cross-resistant to VP-16, ADR, camptothecin (CPT), SN-38 and vincristine (VCR). The enzymatic activities of both Topo I and Topo II in these cells were decreased to one-fourth of that observed in the parental cells. Furthermore, the decreased activities were accompanied by lower expression at the mRNA and protein levels. A549 / TAS cells acquired cross-resistance to VP-16, ADR and VCR, though the Topo activities were virtually unchanged. In this cell line, the intracellular accumulation of TAS-103 was significantly decreased and the expression of multidrug resistance associated protein (MRP) was elevated when compared with the parental cells. The results indicate that the affected activities of Topo I and / or Topo II, and in some instances decreased accumulation of TAS-103, are associated with the development of resistance to TAS-103, although the main mechanism of resistance to TAS-103 varied among cell lines.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

The striking effect of hyperbaric oxygenation therapy in the management of chronic idiopathic intestinal pseudo-obstruction.

Chronic idiopathic intestinal pseudo-obstruction is one of the disorders that is most refractory to medical and surgical treatment. Even when patients are given nutritional support, including total parenteral nutrition, obstructive symptoms seldom disappear. We report a case of chronic idiopathic intestinal pseudo-obstruction, due to myopathy, in which hyperbaric oxygenation therapy was strikingly effective. The presence of myopathy was histologically confirmed on the surgically resected jejunal specimen. Hyperbaric oxygenation resulted not only in relief of the patient's obstructive symptoms but also in a rapid decrease of abnormally accumulated intestinal gas. At last, he could resume oral intake without any critical adverse effects. These observations strongly suggest that hyperbaric oxygenation can be an effective therapy in the management of chronic idiopathic intestinal pseudo-obstruction.

Chronic Disease↗
PubMed2000

[Syntheses of biologically active natural products using metal-mediated reactions as key reactions].

This review deals with total syntheses of biologically active natural products by the use of metal-mediated coupling reactions as key steps. First, we explored the coupling reactions mediated by samarium (II) diiodide (SmI2), which is a useful versatile one electron reducing reagent. The SmI2-mediated coupling reactions of N,N-dibenzyl-alpha-bromoamide and N,N-bis(p-methoxyphenyl)-alpha-bromoamide with carbonyl compounds gave the corresponding beta-hydroxyamides, respectively. Then, oxidative treatment of compound 6c with ceric (IV) ammonium nitrate (CAN) gave d,l-myrmicacine (7b). Synthesis of pyrrolizidine alkaloid pyrrolam A (8), which causes damage to fertilized eggs at a low concentration, was accomplished via the SmI2-mediated cyclization between a bromoalkyl and ynamide group. Next, (+/-)-oxerine (15), a monoterpene alkaloid, was synthesized starting from 3-bromopyridine. The synthesis of (+/-)-oxerine (15) was also carried out via the SmI2-mediated intramolecular cyclization of gamma-ethynyl bromide (40). Next, we focused on the palladium-catalyzed oxidation of alcohol and tried to expand it to the intermolecular cyclization. As a result, treatment of hydroxy-enamines and hydroxy-amines with a palladium catalyst gave the corresponding pyrroles and indoles in moderate to good yields. Finally, the syntheses of three pyrrolidine alkaloids were described. The chromium (II) chloride-mediated coupling reactions of (R)- and (S)-Garner aldehydes (56 and 57) with allyl bromides proceeded with moderate stereoselectivity to afford the corresponding homoallyl alcohols, which were converted to (2R, 3S)-2-hydroxymethyl-3-hydroxypyrrolidine (61), (2R, 3R, 4R)-3-hydroxy-4-methylproline (66), and the enantiomer (77) of (-)-bulgecinine (78).

Bromine Compounds↗
PubMed2000

Isolation of a 41-kDa protein with cell adhesion activity for animal tumor cells from the mushroom Hypsizigus marmoreus by affinity chromatography with type IV collagen immobilized on agarose.

A type IV collagen-binding protein of 41 kDa was isolated from the mushroom Hypsizigus marmoreus and the protein was designated as HM41. The Western blotting analysis with anti-HM41 antibodies demonstrated that HM41 was unrelated to HM23, which had been shown to have an affinity for type IV collagen. The microsequence analysis of the membrane-blotted peptides generated by fragmentation with cyanogen bromide showed no homologous proteins reported. HM41 had cell adhesion-promoting activity for murine Lewis lung carcinoma LL2 cells and human fibrosarcoma HT1080 cells. These results indicate that HM41 is a hitherto undescribed fungus protein that can interact both with animal extracellular matrix protein type IV collagen and with animal tumor cells.

Agaricales↗
PubMed2000

New Cdc25B tyrosine phosphatase inhibitors, nocardiones A and B, produced by Nocardia sp. TP-A0248: taxonomy, fermentation, isolation, structural elucidation and biological properties.

Strain TP-A0248 which produces two new Cdc25B tyrosine phosphatase inhibitors and also possessing antifungal activity, designated nocardiones A (1) and B (2), was considered to belong to the genus Nocardia on the basis of literature comparison of chemotaxonomic properties. The nocardiones were isolated by solvent extraction of fermentation broth of Nocardia sp. TP-A0248 and purified by the conventional column chromatography. Spectroscopic studies led to determination that 1 and 2 belong to a class compound of naphtho[1,2-b]furan-4,5-diones. Compound 1 inhibited the activity of Cdc25B, PTP1B and FAP-1 protein tyrosine phosphatases at a concentration of 10 microM. It also showed moderate in vitro antifungal and cytotoxic activity.

Antifungal Agents↗
PubMed1999

Co-expression of 3-ketoacyl-ACP reductase and polyhydroxyalkanoate synthase genes induces PHA production in Escherichia coli HB101 strain.

The Escherichia coli 3-ketoacyl-ACP reductase gene (fabGEc) was cloned using a PCR technique to investigate the metabolic link between fatty acid metabolism and polyhydroxyalkanoate (PHA) production. Three plasmids respectively harboring fabGEc and the poly-3-hydroxyalkanoate synthesis genes phaCAc and phaC1Ps from Aeromonas caviae and Pseudomonas sp. 61-3 respectively were constructed and introduced into E. coli HB101 strain. On a two-stage cultivation using dodecanoate as the sole carbon source, recombinant E. coli HB101 strains harboring fabGEc and phaC genes accumulated PHA copolymers (about 8 wt% of dry cell weight) consisting of several (R)-3-hydroxyalkanoate units of C4, C6, C8, and C10. It has been suggested that overexpression of the fabGEc gene leads to the supply of (R)-3-hydroxyacyl-CoA for PHA synthesis via fatty acid degradation.

3-Oxoacyl-(Acyl-Carrier-Protein) Reductase↗
PubMed1999

Cell adhesion activity for murine carcinoma cells of a wheat germ 55-kDa protein with binding affinity for animal extracellular matrix proteins.

A wheat germ 55-kDa protein was isolated by affinity chromatography with Matrigel immobilized on agarose, followed by preparative gel electrophoresis. This Matrigel-binding protein designated as WG-55 had an amino-terminal amino acid sequence which is identical to that of a putative mature form of wheat storage protein Gbl 1. WG-55 reacted with concanavalin A, indicating its glycoprotein nature as expected from the amino acid sequence of Gbl 1. As expected, similarly, WG-55 exhibited RGD-dependent cell adhesion activity for murine carcinoma cells. These data suggest that WG-55 or mature Gbl 1 protein may play a role in plant cell adhesion.

Amino Acid Sequence↗
PubMed1999

A de novo splice donor site mutation causes in-frame deletion of 14 amino acids in the proteolipid protein in Pelizaeus-Merzbacher disease.

Pelizaeus-Merzbacher disease (PMD) is a leukodystrophy associated with mutations in the proteolipid protein (PLP) gene. Jimpy is a mouse model of human PMD, and a splice site mutation in Jimpy causes the deletion of exon 5 from the PLP mRNA, producing a truncated form of PLP. We describe a de novo point mutation at the 5' splice donor site of exon 5 in a 17-year-old male with PMD, which results in the skipping of 42 base pairs of exon 5. The mutation removes only 14 amino acids in-frame of PLP. This is a novel splice donor site mutation in the human PLP gene. Moreover, the results indicate that the 14-amino acid deletion in the PLP is responsible for oligodendrocyte cell death and the development of PMD.

Adolescent↗