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Biomedical subjects

A Matsuda

Publications and source records attributed to A Matsuda.

At least 127 records · Page 7Linked to original sources
PubMed1999

Mechanism-based design of inosine 5-monophosphate dehydrogenase inhibitors: synthesis and biological activities of 5-ethynyl-1-beta-D-ribofuranosylimidazole-4-carboxamide (EICAR) and its derivatives.

Inosine 5 -monophosphate dehydrogenase (IMPDH) catalyzes the nicotinamide adenine dinucleotide (NAD)-dependent oxidation of inosine 5 -monophosphate (IMP) to xanthosine 5 -monophosphate (XMP), and is one of the key rate-determining enzymes of de novo guanine nucleotide biosynthesis in mammalian systems. Based on the proposed catalytic mechanism of IMPDH, we designed and synthesized 5-ethynyl-1-beta-D-ribofuranosylimidazole-4-carboxamide (5b, EICAR) from 5-amino-1-beta-D-ribofuranosylimida-zole-4-carboxamide (AICAR) via palladium chemistry. EICAR is a potent cytostatic agent that inhibits various tumor cells in culture including human solid tumor cells in vitro and in vivo. EICAR also showed broad-spectrum antiviral activities, about 10- to 100-fold greater than those of ribavirin. An examination of the structure-activity relationships revealed that an alkynyl group, especially an ethynyl group at the 5-position, is important for its activity due to the inhibition of IMPDH. The mode of action of EICAR is also discussed.

Animals↗
PubMed1999

Prominent increase of macrophage migration inhibitory factor in the sera of patients with uveitis.

PURPOSE: To investigate pathogenesis underlying endogenous uveitis, macrophage migration inhibitory factor (MIF) was quantified in sera of patients. METHODS: Sera were obtained from the 55 patients with uveitis (24 with Behçet's disease; 9 with Vogt-Koyanagi-Harada's [VKH] disease; 22 with sarcoidosis) and 58 healthy control subjects. MIF levels were determined by a human MIF enzyme-linked immunosorbent assay. RESULTS: The mean MIF levels in the sera of the patients with Behçet's disease, VKH disease, and sarcoidosis and of healthy control subjects were 60.4+/-9.0 (mean+/-SE) ng/ml, 16.5+/-2.9 ng/ml, 27.1+/-5.6 ng/ml, and 5.4+/-0.04 ng/ml, respectively. The average levels of MIF in the sera of uveitis patients were significantly higher (P < 0.0001) than those of healthy control subjects. The high levels of MIF were especially noted in patients with Behçet's disease at the ocular exacerbation stage and patients with sarcoidosis at the severe uveitis stage. CONCLUSIONS: Significant increase of MIF in sera was characteristic of uveitis, and MIF may be a usefull laboratory parameter to use to comprehend the clinical course of uveitis.

Behcet Syndrome↗
PubMed1998

Nucleosides and nucleotides. 180. Synthesis and antitumor activity of nucleosides that have a hydroxylamino group instead of a hydroxyl group at the 2'- or 3'-position of the sugar moiety.

The design and synthesis of potential antitumor antimetabolites 2'-deoxy-2'-(hydroxylamino)uridine (15), -cytidine (19, 2'-DHAC), and -adenosine (35), their regioisomers, 3'-deoxy-3'-(hydroxylamino)uridine (40) and -cytidine (45, 3'-DHAC), and their 2'-deoxy analogues, 2', 3'-dideoxy-3'-(hydroxylamino)uridine (49) and -cytidine (52, 3'-dDHAC), are described. We measured the pKa values of the hydroxylamino group in 15 and 40 using 13C NMR spectroscopy as a function of pH to be 2.9 and 3.4, respectively. We also found that these nucleosides gradually decomposed in neutral solution but not in acidic solution. This decomposition may be related to the generation of aminoxy radicals at the sugar moiety. The in vitro cytotoxicity of these nucleosides was evaluated using L1210 and KB cells. 2'-DHAC (19) inhibited the growth of L1210 and KB cells, with IC50 values of 1.58 and 1.99 microM, respectively. 3'-DHAC (45) and 3'-dDHAC (52) were also cytotoxic against L1210 cells, with IC50 values of 4.03 and 1.84 microM, respectively, but not against KB cells. The cytotoxicity of 2'-DHAC (19) and 3'-DHAC (45) against L1210 cells in vitro was reversed by the addition of cytidine, while that of 3'-dDHAC (52) was reversed by 2'-deoxycytidine. 2'-DHAC (19) and 3'-dDHAC (52) mainly inhibited DNA synthesis in L1210 cells, while 3'-DHAC (45) inhibited RNA synthesis. We also evaluated the antitumor activities of 2'-DHAC (19) and 3'-DHAC (45) against murine Meth-A fibrosarcoma cells in vivo. 2'-DHAC (19) was more active than 3'-DHAC (45) when administered intravenously on days 1-10 consecutively at 10 mg/kg/day. 2'-DHAC (19) inhibited tumor growth at a rate of 66.9%.

Animals↗
PubMed1998

Role of histamine H1 and H2 receptor antagonists in the prevention of intimal thickening.

Vascular smooth muscle cell migration to the intima from the media and proliferation in the intima play key roles in atherosclerosis and restenosis after coronary angioplasty. Histamine released from adherent platelets at the injured artery and from mast cells in atheromas has stimulant actions on both smooth muscle cell migration and proliferation, and histamine receptor antagonists abolish the effect of histamine in vitro. The aim of this study was to examine the effect of histamine receptor antagonists on intimal thickening. Endothelial injury in the mouse femoral artery was induced by a photochemical reaction between localized irradiation by green light and intravenously administered rose bengal. The histamine H1 receptor antagonist, diphenhydramine, at a dose of 30 mg/kg or the histamine H2 receptor antagonist, cimetidine, at a dose of 200 mg/kg was intraperitoneally administered to mice for 21 days after endothelial injury. Twenty-one days after endothelial injury, morphometric analysis was performed to measure the cross-sectional areas of the intima and media. Diphenhydramine significantly reduced the intimal area to 1.1 +/- 0.3 (x 10(-3) mm2) compared with the value in the control group, which was 6.2 +/- 1.4 (x 10(-3) mm2), but cimetidine (5.5 +/- 1.9, x 10(-3) mm2) did not. Similarly, the ratio of intimal area to medial area in the diphenhydramine-treated group but not in the cimetidine-treated group was significantly reduced (83%). In the in vitro study, cimetidine inhibited neither proliferation nor migration of mouse vascular smooth muscle cells stimulated by platelet-derived growth factor (PDGF). In contrast, diphenhydramine significantly (P < 0.05) inhibited proliferation in a dose-dependent manner, but did not inhibit migration. These results suggest that diphenhydramine, a histamine H1 receptor antagonist, reduced the formation of intimal hyperplasia, at least in part due to inhibition of cell proliferation. However, cimetidine, a histamine H2 receptor antagonist, was ineffective. Histamine may play a key role in intimal thickening, in part via histamine H1 receptors in this model.

Animals↗
PubMed1998

Effects of 2'-O-(trifluoromethyl)adenosine on oligodeoxynucleotide hybridization and nuclease stability.

The synthesis and properties of oligodeoxynucleotides (ODNs) containing 2'- O -(trifluoromethyl)adenosine (2) are described. 2'- O -(Trifluoromethyl)adenosine (2) or N 6-(benzoyl)-2'- O -(trifluoromethyl)adenosine (6) was obtained in 22 or 32% yield by treating 2'- O -[(methylthio)thiocarbonyl]-3',5'- O -(1,1,3, 3-tetraisopropyldisiloxane-1,3-diyl)(TIPDS)adenosine (4) or N 6, N 6-(dibenzoyl)-2'- O -[(methylthio)thiocarbonyl]-3',5'- O -(TIPDS)-adenosine (5), respectively, with pyridinium poly-(hydrogen fluoride) in the presence of 1,3-dibromo-5,5-dimethylhydantoin. Nucleoside 2 was incorporated into DNA hexadecamers. ODNs that contained 2 reduced the thermal stability of duplexes with their complementary DNAs but increased the thermal stability of duplexes with their complementary RNAs. Furthermore, ODNs containing 2 were slightly more resistant to snake venom phosphodiesterase than an unmodified ODN.

Adenosine↗
PubMed1998

Evidence supporting the activity of 2'-C-cyano-2'-deoxy-1-beta-D-arabino-pentafuranosylcytosine as a terminator in enzymatic DNA-chain elongation.

To investigate the stability of 2'-C-cyano-2'-deoxy-1-beta-D-arabino-pentafuranosylcytosine 3'-phosphoric acid, its thymidine ester was prepared via the phosphoramidite method using allyl protection for the phosphate function. This ester is stable under acidic conditions but extremely labile under basic conditions, decomposing with a cleavage of the internucleotide bond even at pH 7.3.

Antineoplastic Agents↗
PubMed1998

Synthesis and biological activity of conformationally restricted analogues of milnacipran: (1S, 2R)-1-phenyl-2-[(R)-1-amino-2-propynyl]-N,N- diethylcyclopropanecarboxamide is a novel class of NMDA receptor channel blocker.

Conformationally restricted analogues of (+/-)-(Z)-2-aminomethyl-1-phenyl-N,N-diethylcyclopropanecarboxamide++ + [milnacipran, (+/-)-1] were designed on the basis of its characteristic cyclopropane structure and were synthesized enantioselectively to develop efficient NMDA receptor antagonists. Among these analogues, (1S,2R)-1-phenyl-2-[(R)-1-amino-2-propynyl]-N, N-diethylcyclopropanecarboxamide (2d) had one of the most potent affinities for the receptor, with a Ki value of 0.29 microM. The blockade of NMDA receptor channels expressed by Xenopus oocytes by 2d was investigated in detail, and 2d was identified as a new class of open channel blocker against this receptor.

Animals↗
PubMed1998

Upregulation of a new microglial gene, mrf-1, in response to programmed neuronal cell death and degeneration.

Cerebellar granule neurons isolated from postnatal day 7 (P7) rats and grown in normal K+ medium begin to degenerate at approximately 4 d in vitro (DIV) and die. To search for genes upregulated in the process of neuronal cell death, differential hybridization was performed with subtracted cDNA probes and a cDNA library from 5 DIV. One of the genes isolated was microglial response factor-1 (mrf-1), which encoded a sequence of 177 amino acids with a single EF-hand calcium-binding motif. By Northern blots, the transcript was upregulated in cerebellar culture at 4 DIV, peaked at 6 DIV, and decreased at 7 DIV. Upregulation was also found when the apoptosis of granule cells was induced by replacing high K+ medium with normal K+ medium. However, when non-neuronal cells were thoroughly eliminated with aphidicolin, an antimitotic agent, the upregulation at 4-7 DIV did not occur. By immunocytochemistry, MRF-1 was detected at 5 DIV in OX-42-positive cells (microglia), and it exhibited an increase in response to granule cell death. MRF-1 levels in microglia purified from cerebral cortex also upregulated in the presence of 5 DIV granule cells. In the developing cerebellum in vivo, levels of mrf-1 mRNA transiently increased in the early postnatal stages, reaching a peak at P7 when cerebellar neurons and astrocytes undergo extensive apoptosis. In adult brain sections, MRF-1 was detected in the perikarya and processes of ramified/resting microglia, and peripheral motor nerve dissection prominently increased the expression in activated microglia surrounding injured central motoneurons. Therefore, mrf-1 appears to be one of the microglial genes that respond to neuronal cell death and degeneration.

Amino Acid Sequence↗
PubMed1998

Nucleosides and nucleotides. 176. 2'-Deoxy-2'-hydroxylaminocytidine: a new antitumor nucleoside that inhibits DNA synthesis although it has a ribonucleoside structure.

The design and synthesis of potential antitumor antimetabolites 2'-deoxy-2'-hydroxylaminouridine (2'-DHAU) and -cytidine (2'-DHAC) are described. We found that 2'-DHAC in neutral solution generated 2'-aminoxy radicals at room temperature. 2'-DHAC inhibited the growth of L1210 and KB cells, with IC50 values of 1.58 and 1.99 microM, respectively, more potently than 2'-DHAU, with IC50 values of 34.5 and 27.3 microM, respectively. 2'-DHAC was effective against 9 human cell lines, with IC50 values of in the micromolar range. The in vivo antitumor activity of 2'-DHAC was also examined using the mouse leukemia P388 model, which gave a T/C value 167%. Phosphorylation of 2'-DHAC by uridine/cytidine kinase was essential for its cytotoxicity, as suggested by a competition experiment using several common nucleosides. Inhibition of DNA synthesis was the predominant mechanism of action of 2'-DHAC, although it has a ribo-configuration.

Animals↗
PubMed1998

Nucleosides and nucleotides. 175. Structural requirements of the sugar moiety for the antitumor activities of new nucleoside antimetabolites, 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine and -uracil1.

We previously designed 1-(3-C-ethynyl-beta-d-ribo-pentofuranosyl)uracil (EUrd) and its cytosine congener (ECyd) as potential multifunctional antitumor nucleoside antimetabolites. They showed potent and broad-spectrum antitumor activity against various human and mouse tumor cells in vitro and in vivo. To clarify the structure-activity relationship of the sugar moiety, various 3'-C-carbon-substituted analogues, such as 1-propynyl, 1-butynyl, ethenyl, ethyl, and cyclopropyl derivatives, of ECyd and EUrd were synthesized. We also prepared 3'-deoxy analogues and 3'-homologues of ECyd and EUrd with different configurations to determine the role of the 3'-hydroxyl group and the length between the 3'-carbon atom and the ethynyl group and a 2'-ethynyl derivative of ECyd to determine the spatial requirements of the ethynyl group. The in vitro tumor cell growth inhibitory activities of these nucleosides against mouse leukemic L1210 and human KB cells showed that ECyd and EUrd were the most potent inhibitors in the series, with IC50 values of 0.016 and 0.13 microM for L1210 cells and 0.028 and 0.029 microM for KB cells, respectively. Only 3'-C-1-propynyl and -ethenyl derivatives of ECyd showed greatly reduced cytotoxicity. We found that the cytotoxic activity of these nucleosides predominantly depended on their first phosphorylation by uridine/cytidine kinase.

Animals↗
PubMed1998

Antitumor activity of a novel orally effective nucleoside, 1-(2-deoxy-2-fluoro-4-thio-beta-D-arabinofuranosyl)cytosine.

The antitumor activity of a novel 4'-thionucleoside, 1-(2-deoxy-2-fluoro-4-thio-beta-D-arabinofuranosyl)cytosine (4'-thio-FAC), was evaluated. 4'-Thio-FAC inhibited the in vitro growth of various human cancer cell lines, particularly the growth of cell lines established from gastric and colorectal carcinomas, while its oxy-type congener 1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)cytosine (FAC) showed little or no activity against such solid cancer cell lines. 4'-Thio-FAC showed a remarkable antitumor effect against human tumors subcutaneously implanted into nude mice and was highly effective even by oral administration. 4'-Thio-FAC was less susceptible to deamination by cytidine deaminase than FAC and 2'-deoxy-2',2'-difluorocytidine (gemcitabine) and therefore is a promising drug candidate for cancer chemotherapy.

Administration, Oral↗
PubMed1998

CREB-induced transcriptional activation depends on mGluR6 in rod bipolar cells.

To investigate the molecular mechanisms of stimuli-induced transcriptional activation in neuronal cells, we have investigated the light-induced gene expression in the neural retina of rats. The immunoreactivity for phosphorylated cAMP responsive element binding protein (PCREB-IR) was expressed in the outer half of the inner nuclear layer (INL) and the ganglion cell layer (GCL) after 5 min exposure to steady light also in mice. In addition to these cells, PCREB-IR was also detected in the inner border of the INL after 5 min exposure to flashing light. Both steady and flashing lights induced c-fos mRNA in the same types of cells as the PCREB-IR-positive cells. Majority of PCREB immunoreactive nuclei in the outer half of the INL were also immunopositive for anti-protein kinase C alpha (PKC alpha), a marker of rod bipolar cells, while CaM kinase IV immunoreactivity was not detected in these cells. PCREB-IR and c-fos gene expression in the PKC alpha positive rod bipolar cells were lost in mice lacking metabotropic glutamate receptor 6 (mGluR6). Thus, we propose that the transcriptional response of CREB to light stimulation in rod bipolar cells is regulated via mGluR6.

Animals↗
PubMed1998

Disruption of lymphocyte function and signaling in CD45-associated protein-null mice.

CD45-AP specifically associates with CD45, a protein tyrosine phosphatase essential for lymphocyte differentiation and antigen receptor-mediated signal transduction. CD45 is thought to mediate antigen receptor signaling by dephosphorylating regulatory tyrosine residues on Src family protein tyrosine kinases such as Lck. However, the mechanism for regulating CD45 protein tyrosine phosphatase activity remains unclear. CD45-AP-null mice were created to examine the role of CD45-AP in CD45-mediated signal transduction. T and B lymphocytes showed reduced proliferation in response to antigen receptor stimulation. Both mixed leukocyte reaction and cytotoxic T lymphocyte functions of T cells were also markedly decreased in CD45-AP-null mice. Interestingly, the interaction between CD45 and Lck was significantly reduced in CD45-AP-null T cells, indicating that CD45-AP directly or indirectly mediates the interaction of CD45 with Lck. Our data indicate that CD45-AP is required for normal antigen receptor signaling and function in lymphocytes.

Animals↗
PubMed1998

Synthesis of L-enantiomers of 4'-thioarabinofuranosyl pyrimidine nucleosides.

L-Enantiomers of 4'-thioarabinofuranosyl pyrimidine nucleosides were synthesized from D-xylose. Methyl 2,3,5-tri-O-benzyl-D-xylofuranoside 6 was converted to the corresponding xylitol 7, which was treated with MsCl and then Na2S to give 1,4-anhydro-L-4-thioarabitol 8. As previously reported, Pummerer rearrangement of 8 followed by glycosylation with a silylated thymine and N4-acetylcytosine derivative and deprotection gave the corresponding alpha- and beta-L-4'-thioarabinofuranosyl pyrimidine nucleosides.

Antimetabolites, Antineoplastic↗
PubMed1998

Development and biochemical characterization of a 2'-C-cyano-2'-deoxy-1-beta-D-arabino-pentofuranosylcytosine (CNDAC)-resistant variant of the human fibrosarcoma cell line HT-1080.

2'-C-Cyano-2'-deoxy-1-beta-D-arabino-pentofuranosylcytosine (CNDAC) is an antitumor nucleoside with a novel chemical structure that exerts potent antitumor activity against various human tumor cells in vitro and in vivo. In order to be active it needs to be phosphorylated by deoxycytidine (dCyd) kinase. We induced resistance to CNDAC in the human fibrosarcoma cell line HT-1080 by exposure to increasing concentrations of CNDAC. The resistant cells showed over 560 times higher resistance as compared to that of the parental HT-1080 cells and were cross-resistant to the other 2'-deoxycytidine derivatives. The dCyd kinase mRNA expression of the resistant cells decreased and there was the expression of aberrant mRNA of dCyd kinase which contained a 116-nucleotide deletion within the coding region, corresponding to the fifth exon of the gene. The dCyd kinase enzymatic activity of the resistant cells was deficient. The initial uptake of CNDAC into the resistant cells was similar to that of the parental cells. However, the incorporation of CNDAC into the DNA fraction of the resistant cells was significantly less than that of the parent cells. These results led us to conclude that the acquired resistance to CNDAC can be attributed to a deficiency of dCyd kinase activity, which should be based on a remarkable decrease in mRNA expression and genetic mutation of the dCyd kinase gene, but not on cellular CNDAC accumulation.

Antimetabolites, Antineoplastic↗