Search PubMed⌕ Search

Biomedical subjects

Y Sugimoto

Publications and source records attributed to Y Sugimoto.

At least 73 records · Page 4Linked to original sources
PubMed2001

Generation of hepatitis C virus-specific cytotoxic T lymphocytes from healthy individuals with peptide-pulsed dendritic cells.

BACKGROUND AND AIMS: In hepatitis C virus (HCV) infection, cytotoxic T lymphocytes (CTL) are involved in liver inflammation and contribute to the reduction of viral load. Antibodies for HCV-CTL precursor frequencies (CTLpf) are relatively low in chronic hepatitis C, and this may be related to the poor CTL response in vivo. The aim of this study was to assess the efficacy of dendritic cells (DC) as antigen-presenting cells in CTL generation from low CTLpf. METHODS: To confirm the rationale of using DC to prime naive T cells, five HCV-uninfected individuals were enrolled in the study. We obtained DC by maturation from peripheral progenitors under stimulation with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-4 and IL-1alpha. Autologous T cells were cultured with DC or concanavalin-A-induced blasts loaded with four HCV-derived peptides bearing human leukocyte antigen (HLA)-A*0201 or -A24 motifs for 28 days under IL-7 and IL-2 stimulation. The lytic activity against peptide-pulsed targets was assessed by using a [51Cr]-releasing assay. RESULTS: The DC strongly expressed HLA class I, II, B7-1 and B7-2, but not phenotypic markers of T-, B-, natural killer (NK)-cells or monocytes. The CD8-positive, HLA-class I-restricted and HCV peptide-specific CTL were generated with DC from HLA-A antigen-matched subjects, whereas no CTL activity was detected with concavalin (Con-A) blasts. We were thus able to generate HCV specific CTL from naive precursors with peptide-pulsed DC. CONCLUSIONS: This DC-based system can be used to generate CTL of desired antigen specificity, even from a source with low CTLpf.

Adult↗
PubMed2001

Acutudaurin from cultured roots of Menispermum dauricum.

A new alkaloid, acutudaurin, was isolated from cultured roots of Menispermum dauricum, a rich source of the chlorine-containing alkaloid acutumine and its dechlorinated analogue dechloroacutumine. The structure of acutudaurin was determined to be 2',3'-dihydro-5-hydroxy-4,6',7'-trimethoxy- 1'-methylspiro[3-cyclohexene-1,10'-[3a,7a]propano[1H]indole]-2,5'(4'H)-dione by spectroscopic methods.

Alkaloids↗
PubMed2001

Isolation of NPC1-deficient Chinese hamster ovary cell mutants by gene trap mutagenesis.

Chinese hamster ovary cell mutants defective in the NPC1 gene (NPC1-trap) were generated by retrovirus-mediated gene trap mutagenesis from a parental cell line JP17 expressing an ecotropic retrovirus receptor. Insertion of the gene trap vector in the NPC1 gene and the absence of the gene product were verified by 5'RACE and immunological analyses, respectively. NPC1-trap cells showed intracellular accumulation of low-density lipoprotein (LDL)-derived cholesterol and had an increased level of unesterified cellular cholesterol. Cholesterol biosynthesis through the mevalonate pathway was upregulated in the mutant cells as assessed by [(14)C]acetate incorporation into cellular sterols. When JP17 cells were depleted of lipoproteins and then loaded with LDL, cell surface LDL receptors were promptly downregulated and the mature form of the sterol regulatory element-binding protein-1 disappeared from the nucleus. These responses to LDL were obviously retarded in NPC1-trap cells, suggesting an impaired response of the cholesterol-regulatory system to LDL. NPC1-trap cells will be a useful tool to study the regulation of cellular cholesterol homeostasis and the pathogenesis of Niemann-Pick disease type C.

Animals↗
PubMed2001

Guidance of glial precursor cell migration by secreted cues in the developing optic nerve.

Oligodendrocyte precursors are produced in restricted foci of the germinative neuroepithelium in embryo brains and migrate to their sites of function, while astrocytes are produced in a wider area in the neuroepithelium. We investigated the guidance mechanisms of glial precursor (GP) cell migration in the optic nerve. GP cell migration in newborn rat optic nerve was monitored by the UV-thymine-dimer (TD) method. A double labeling study using NG2 and TD revealed that many of these in vivo migrating cells were NG2 positive, while some of them with large TD-positive nuclei were NG2 negative. An in vitro cell migration study using optic nerve with chiasma and/or eyeball tissue revealed that the GP cells migrated under the guidance of repulsive cues secreted from the optic chiasma. We detected the expression of netrin 1 and Sema3a in the optic chiasma, and that of Unc5h1 and neuropilin 1 in the optic nerve. Co-culture experiments of the optic nerve with cell clusters expressing guidance cues revealed that the migrating GP cells in the optic nerve were heterogeneous. Netrin 1 repelled a subtype of NG2-positive and PLP-positive GP cells with small nuclei. Sema3a repelled a subtype of GP cells with large nuclei.

Animals↗
PubMed2001

The 5-HT1A receptor agonist 8-hydroxy-2-di-n-(propylamino)tetralin (8-OH-DPAT) induces hyperglucagonemia in rats.

Effects of the 5-HT1A receptor agonist 8-hydroxy-2-di-n-(propylamino)tetralin (8-OH-DPAT) on plasma glucagon levels were investigated. 8-OH-DPAT increased plasma glucose and glucagon levels in rats. Both hyperglycemia and hyperglucagonemia elicited by 8-OH-DPAT were prevented by the 5-HT1A receptor antagonist pindolol and prior adrenodemedullation. These results suggest that increases in plasma glucagon levels induced by 8-OH-DPAT were based on the adrenaline release from the adrenal gland and its effects may contribute to its hyperglycemic effects.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2001

Effects of the 5-HT2 receptor antagonist, ritanserin on hyperthermia and depletion of 5-HT in frontal cortex induced by a 5-HT releasing drug, p-chloroamphetamine (PCA) in mice.

Effects of the 5-HT2 receptor antagonist, ritanserin on hyperthermia and depletion of 5-HT induced by the 5-HT-releasing drug, p-chloroamphetamine (PCA) were investigated. Ritanserin significantly suppressed PCA-induced hyperthermia in mice. PCA elicited decreases in 5-HT levels in the mouse frontal cortex. 5-HT reduction elicited by PCA was also attenuated by pretreatment with ritanserin. Since hyperthermia facilitates neurotoxicity induced by amphetamine analogue, ritanserin may inhibit PCA-induced 5-HT neurotoxicity by inhibiting hyperthermia.

Animals↗
PubMed2001

The 5-HT2C/2B receptor agonist m-chlorophenylpiperazine (mCPP) inhibits 2-deoxy-D-glucose (2-DG)-induced hyperphagia in rats.

Effects of the 5-HT2C2/2B receptor agonist m-chlorophenylpiperazine (mCPP) on hyperphagia elicited by 2-deoxy-D-glucose (2-DG) were investigated in rats. mCPP apparently reduced 2-DG-induced hyperphagia. Suppressive effects of mCPP on hyperphagia induced by 2-DG were inhibited by the 5-HT2A/2B/2C receptor antagonist, ritanserin, although the 5-HT2, receptor antagonist ketanserin was without effect. Thus, inhibitory effects of mCPP on 2-DG-induced hyperphagia are mediated by the 5-HT2C/2B receptor. Our results demonstrate that mCPP can inhibit the bulimia model, 2-DG-induced hyperphagia.

Animals↗
PubMed2001

Effects of peppermint (Mentha piperita L.) extracts on experimental allergic rhinitis in rats.

The present study was carried out to clarify the effects of extracts of the leaves of Mentha piperita L. on experimental allergic rhinitis. The 50% EtOH extract of peppermint inhibited histamine release from rat peritoneal mast cells induced by compound 48/80. The effect was dose-dependent and significant inhibition was observed at a concentration of 3 microg/ml. In addition, the 50% EtOH eluate separated from the 50% EtOH extract of peppermint by column chromatography (DIAION HP-20) was also effective in inhibiting histamine release at a concentration of 1 microg/ml. Nasal symptoms, sneezing and nasal rubbing induced by antigen challenge in actively sensitized rats were inhibited by oral administration of the 50% EtOH eluate. Significant inhibition of sneezing and nasal rubbing was observed at doses of 300 and 1000 mg/kg, p.o., respectively. Furthermore, the 50% EtOH eluate inhibited dye leakage into the nasal cavity of rats induced by antigen in a dose-dependent manner. These results suggested that extracts of Mentha piperita L. may be clinically effective in alleviating the nasal symptoms of allergic rhinitis.

Animals↗
PubMed2001

Diastereoselective synthesis of (2R,4R)-2-aryl-4-hydroxypyrrolidine: preparation of the side chain of novel carbapenem.

Improved synthesis of the trans-3,5-disubstituted pyrrolidin-3-ylthio side-chain of the novel carbapenem 1 was achieved via stereoselective reduction of the 1-aryl-1-butanone derivative 5 and successive intramolecular cyclization of the resulting chiral alcohol 6. The 1-aryl-1-butanone derivative 5 was obtained by a coupling reaction of protected 4-hydroxy-2-pyrrolidone with aryl-Grignard reagent.

Carbapenems↗
PubMed2001

Practical synthesis of a 1beta-methylcarbapenem, J-111,225, using 4-mercapto-2-[4-(N-methylaminomethyl)phenyl]pyrrolidine as a precursor.

An effective and practical procedure for the synthesis of J-111,225 (1), a new 1beta-methylcarbapenem, was developed using 4-mercapto-2-14-(N-methylaminomethyl)phenyl]pyrrolidine (2a) as a precursor. The coupling reaction of 2a with p-nitrobenzyl (PNB)-protected 1beta-methylcarbapenem enolphosphate 3a and successive removal of PNB group afforded J-111,225 (1) in significantly increased yield compared to the ordinary procedure using a C-2 side-chain thiol with amino-protective groups.

Anti-Infective Agents↗
PubMed2001

Effects of histidine on working memory deficits induced by the 5-HT1A-receptor agonist 8-OH-DPAT.

We investigated the effects of histidine on spatial memory deficits induced by the 5-HT1A-receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). Working memory deficits were elicited by 8-OH-DPAT without affecting reference memory. Histidine improved the working memory deficit induced by 8-OH-DPAT at doses causing a significant increase in brain histamine content. This finding suggests that the histaminergic system regulates 8-OH-DPAT-induced working memory deficit.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2001

Substrate phage as a tool to identify novel substrate sequences of proteases.

Combinatorial phage peptide libraries have been used to identify the ligands for specific target molecules. These libraries are also useful for identification of the specific substrates of various proteases. A substrate phage library has a random peptide sequence at the N-terminus of the phage coat protein and an additional tag sequence that enables attachment of the phage to an immobile phase. When these libraries are incubated with a specific enzyme, such as a protease, the uncleaved phage is excluded from the solution with tag-binding macromolecules. This provides a novel approach to define substrate specificity. The aim of this review is to summarize recent progress on the application of the substrate phage technique to identify specific substrates of proteolytic enzymes. As an example, some of our own experimental data on the selection and characterization of substrate sequences for thrombin, a serine protease, and membrane type-1 matrix metalloproteinase (MT1-MMP) will be presented. Using this approach, the canonical consensus substrate sequence for thrombin was deduced from the selected clones. As expected from the collagenolytic activity of MT1-MMP, a collagen-like sequence was identified in the case of MT1-MMP. A more selective substrate sequence for MT1-MMP was identified during a substrate phage screen. The delineation of the substrate specificity of proteases will help to elucidate the enzymatic properties and the physiological roles of these enzymes. Comprehensive screening of very large numbers of potential substrate sequences is possible with substrate phage libraries. Thus, this approach allows novel substrate sequences and previously unknown target molecules to be defined.

Amino Acid Sequence↗
PubMed2001

[Involvement of TAP2 and LMP7 gene polymorphisms in HCV infection].

We aimed to study whether TAP and LMP polymorphisms could influence the severity of liver disease or the response to IFN treatment in patients with chronic HCV infection. TAPZ*0103 gene frequencies in carriers with normal ALT was significantly higher than that in CLD patients. As for the results of IFN responses, LMP7-K gene frequency in sustained-responders was higher than that in non-responders. Multivariate analysis revealed that LMP7-K and HCV RNA quantity were independent factors influencing the outcome of IFN therapy. Furthermore, among patients with a low viral load, the LMP7-K positive patients had a significantly higher ratio of sustained response compared to those without LMP7-K. The TAP2 polymorphism may be closely associated with low hepatitis activity, whereas the LMP7 polymorphism influences the efficacy of IFN treatment and can be a useful predictive parameter in HCV patients with a low viral load.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

[On the studies of the problem of X-ray units conducted from 1929 to 1937: centering on the studies in American and British radiological societies].

The problem of the units of X-ray exposure originated from the fact that therapists wished to grasp the relationship between the quantity of irradiated X-ray and its effect on medical treatment, and to make a comparative study of each therapeutic result by the same measure. This problem was an interdisciplinary one between physics and radiotherapeutics. In 1925, the Radiological Society of North America settled the Committee on Standardization of X-ray Measurements to study the problem of measuring X-rays, and to guide the members of the Society. The committee was composes of physicists and radiologists in equal number. They developed a large-sized standard chamber and a portable one. L. S. Taylor transported the portable chamber to Europe and by using it he compared and examined British, German and French standard chambers, confirming that each of them could be used as a common standard chamber. Based on these facts the ICRU presented the Annex to the recommendations of 1934 on the standard measuring apparatus. It was shown by physicists that the effect on the human body was not represented only by the quantity of irradiated X-rays and that a description of the quality of X-rays was indispensable. As radiologists' understanding deepened, they came to actively submit proposals to radiological societies in the 1930's. Taking their opinions into consideration, the ICRU recommendations which were practicable for medical purposes were issued in 1937. The effort of American and British radiological societies for a better solution beyond disciplines is suggestive in dealing with interdisciplinary issues.

History, 20th Century↗
PubMed2000

Mechanism responsible for epileptogenic activity by first-generation H1-antagonists in rats.

In the present study, we have demonstrated that multiple first-generation H1-antagonists caused behavioral and EEG seizures in rats. The epileptogenic property of pyrilamine was more potent than either chlorpheniramine or diphenhydramine. In contrast, the second-generation H1-antagonists, loratadine and ebastine did not induce detectable epileptogenic activity. Intraperitoneal injection of histidine inhibited the EEG seizures induced by pyrilamine, diphenhydramine or chlorpheniramine; however no antagonism was observed with physostigmine. These results clearly suggest that the epileptogenic activity of first-generation H1-antagonists is dependent upon a centrally acting histaminergic mechanism.

Animals↗
PubMed2000

Vascular permeability in allergic conjunctivitis in mice lacking histamine H1 receptors.

To clarify the role of histamine H1 receptors in allergic conjunctivitis, changes in vascular permeability of the conjunctiva were measured in histamine H1 receptor deficient mice. Wild-type mice showed a significant increase in vascular permeability of the conjunctiva induced by histamine. However, no such increase was found in histamine H1 receptor deficient mice. On the other hand, no differences were observed between wild-type and histamine H1 receptor deficient mice in response to serotonin. A significant increase in vascular permeability was observed in actively sensitized wild-type mice, whereas no increase was observed in histamine H1 receptor deficient mice. Similar findings were noted in passively sensitized animals. Histamine contents of the conjunctiva were significantly decreased by topical application of antigen in both wild-type and histamine H1 receptor deficient mice after active sensitization with antigen. These findings suggested that vascular permeability in the conjunctiva in allergic conjunctivitis is entirely regulated through histamine H1 receptor.

Animals↗
PubMed2000

Prostaglandin F2alpha-induced expression of 20alpha-hydroxysteroid dehydrogenase involves the transcription factor NUR77.

Prostaglandin F(2)alpha (PGF(2)alpha) binding to its receptor on the rat corpus luteum triggers various signal transduction pathways that lead to the activation of a steroidogenic enzyme, 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD), which in turn catabolizes progesterone. The molecular mechanism underlying PGF(2)alpha-induced 20alpha-HSD enzyme activity has not yet been explored. In this report we show, using mice lacking PGF(2)alpha receptor and pregnant rats, that PGF(2)alpha is responsible for the rapid and massive expression of the 20alpha-HSD gene at the end of pregnancy leading to a decrease in progesterone secretion. We also present evidence that PGF(2)alpha enhances 20alpha-HSD promoter activity. We have determined a region upstream of the -1590 position in the 20alpha-HSD promoter that confers regulation by PGF(2)alpha in ovarian primary cells. This region encompasses a unique transcription factor-binding site with a sequence of a NUR77 response element. Deletion of this motif or overexpression of a NUR77 dominant negative protein caused a complete loss of 20alpha-HSD promoter activation by PGF(2)alpha. NUR77 also transactivated the 20alpha-HSD promoter in transient transfection experiments in corpus luteum-derived cells (GG-CL). This induction required the NUR77-transactivating domain. We also show that PGF(2)alpha induces a very rapid expression of NUR77 that binds to a distal response element located at -1599/-1606 but does not interact with another proximal putative NUR77 response element located downstream in the promoter. A rapid increase in NUR77 mRNA was observed in mice corpora lutea just before parturition at a time when 20alpha-HSD becomes expressed. This increase in the expression of both genes was not seen in PGF(2)alpha receptor knockout mice. By using cyclosporin A and PGF(2)alpha treatment, we established that inhibition of NUR77 DNA binding in vivo prevents PGF(2)alpha induction of the 20alpha-HSD gene in the corpus luteum. Taken together, our results demonstrate, for the first time, that PGF(2)alpha induces in the corpus luteum the expression of the nuclear orphan receptor and transcription factor, NUR77, which in turn leads to the transcriptional stimulation of 20alpha-HSD, triggering the decrease in serum progesterone essential for parturition.

20-Hydroxysteroid Dehydrogenases↗