Efficient Lewis acid-catalyzed stereocontrolled radical polymerization of acrylamides.
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Letter↗
Biomedical subjects
Y Isobe
Publications and source records attributed to Y Isobe.
Entactin-induced inhibition of human amyloid beta-protein fibril formation in vitro.
Amyloid beta-protein (Abeta) fibril in senile plaques may possibly be related to the pathogenesis of Alzheimer's disease (AD). Basement membrane (BM) components are localized to the plaques. Entactin binds the plaque associated BM components. We investigated the potential of entactin to prevent Abeta fibril formation. Thioflavin T fluorometric assay and electron microscopy revealed that entactin significantly inhibited Abeta1-40 (Abeta40) fibril formation at an Abeta40:entactin molar ratio of 50:1. The inhibitory effect of entactin was displayed in a dose-dependent manner. Circular dichroism spectroscopy data indicated that entactin induced a random coil structure in Abeta40. We propose that the ability of entactin to induce random structure is linked to the inhibition of Abeta fibril formation. Entactin may be related to the pathogenesis of AD by regulating Abeta40 fibril formation.
Amyloid beta-Peptides↗
beta-amyloid induces caspase-dependent early neurotoxic change in PC12 cells: correlation with H2O2 neurotoxicity.
We examined neurotoxic effects of Abeta(25-35), an active fragment of beta-amyloid (Abeta), and compared the effect with H2O2 neurotoxicity in PC12 cells. Abeta(25-35) induced the loss of mitochondria function as detected using a tetrazolium salt (WST-1) reduction assay and decreased the number of cells adhering to collagen type 1-coated plates. Abeta(25-35) did not induce cell death, as detected by Hoechst 33342/propidium iodide staining. The caspase tetrapeptide inhibitor z-IETD-fluoromethylketone (FMK) and z-LEHD-FMK inhibited the attenuation of WST-1 reduction induced by Abeta(25-35) and H2O2, while the caspase-3 inhibitor z-DEVD-FMK afforded protection only against H2O2 neurotoxicity. Caspase-3 protease activity was increased by treatment of H2O2 but not Abeta(25-35). Thus, Abeta(25-35) induces early neurotoxic events by activating caspases other than caspase-3. H2O2 -induced oxidative stress may not be implicated in Abeta-induced neurotoxic pathways.
Amyloid beta-Peptides↗
Circadian rhythm of drinking and running-wheel activity in rats with 6-hydroxydopamine lesions of the ventral tegmental area.
Circadian rhythms in drinking and running-wheel (locomotor) activity of rats with 6-hydroxydopamine (6-OHDA, 4 microg/2 microl per rat)-induced lesions in the ventral tegmental area (VTA) were examined under a light-dark (LD) cycle and constant dim light (5 lux). Under the LD cycle, the length of the locomotor activity period was decreased during the dark, and increased during the light period in the lesioned rats. Under the constant dim light conditions, the free-running circadian period (tau) of drinking and activity rhythm was longer in lesioned rats than in sham-operated controls. The elongation of the circadian period was accompanied by decrements in activity. These observations suggest that the mesolimbic dopaminergic system modulates rhythms in circadian drinking and locomotor activity.
Adrenergic Agents↗
Synthesis and structure-activity relationship of diarylamide derivatives as selective inhibitors of the proliferation of human coronary artery smooth muscle cells.
A series of diarylamide derivatives were synthesized and evaluated for their inhibitory activities against human coronary artery smooth muscle cells (SMCs) and human coronary artery endothelial cells (ECs). Compound 2w was superior to the lead compound, Tranilast, in terms of the potency of the activity and cell selectivity.
Amides↗
Structure-activity relationships of quinazoline derivatives: dual-acting compounds with inhibitory activities toward both TNF-alpha production and T cell proliferation.
We synthesized 4-chlorophenethylaminoquinazoline derivatives and evaluated their inhibitory activities toward both TNF-alpha production and T cell proliferation responses. Compound 2f, containing a piperazine ring at the C(7)-position of the quinazoline ring, exhibited more potent inhibitory activities toward both than the lead compound la. A smaller N-substituent in the piperazine ring was required for inhibition of TNF-alpha production.
Animals↗
Melatonin inhibits Arg-vasopressin release via MT(2) receptor in the suprachiasmatic nucleus-slice culture of rats.
The effect of melatonin on the release of Arg-vasopressin (AVP) was analyzed in a suprachiasmatic nucleus-slice explant culture. The release of AVP into the culture medium exhibited a circadian rhythm, with higher level during the subjective day and lower level during the subjective night. Melatonin (500 nM) inhibited the release of AVP. Luzindole, a MT(2) (Mel 1b) melatonin receptor antagonist, attenuated the effect of melatonin on the AVP release. Results indicate that the inhibition of AVP release by melatonin in the suprachiasmatic nucleus-slice culture depends at least in part on the melatonin MT(2) receptor.
Animals↗
Taste-enhancing effects of glycine on the sweetness of glucose: a gustatory aspect of symbiosis between the ant, Camponotus japonicus, and the larvae of the lycaenid butterfly, Niphanda fusca.
The lycaenid butterfly, Niphanda fusca, has a parasitic relationship with its host ant, Camponotus japonicus: the caterpillars may use chemical mimicry to enter the ant nest where they are fed mouth-to-mouth by the adult ants until pupation. Nevertheless, larvae offer their host ants a nutritious secretion that contains 160 mM glucose and 43 mM glycine. Using glucose and glycine mixture as artificial secretions, we investigated the gustatory effect of glucose and/or glycine on the ants. Glycine induced neither feeding behavior nor gustatory response in the ants if its concentration was <500 mM. In the presence of glycine at the concentration in the secretion, however, the ants improved their preference to glucose, and the sugar receptor cell exhibited electrophysiological enhancement of response to glucose in a glycine-concentration-dependent manner. By adding glycine to glucose in their secretions, therefore, the butterfly larvae can manipulate the gustatory sense of the ants. The alluring taste of 'glycine-flavored glucose' could motivate the host ants to feed the larvae and thereby receive the secretions as a reward. The taste enhancement created by the combination of sugar and amino acid may play a role in the evolution of the parasitic relationships of these insects. The taste-enhancing effect appears to be analogous to taste enhancement by 'umami' substances in humans.
Amino Acids↗
Endovascular stent-graft placement for thoracic aortic injury: case report.
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Accidents, Traffic↗
Effects of 5-HT(4) receptor agonist prokinetic agents on the action potential parameters of isolated rabbit myocardium.
The effects of TS-951, a novel gastrointestinal prokinetic agent with 5-HT(4) receptor agonistic action, on the action potential parameters of isolated rabbit Purkinje fiber, ventricular muscle and sinoatrial node, and on the spontaneously beating rates of isolated rabbit right atria were compared with those of cisapride. TS-951 had no effect on the action potential parameters in both rabbit Purkinje fiber and ventricular muscle preparations. However, cisapride significantly prolonged action potential duration (APD) in both preparations. Both TS-951 and cisapride produced a negative chronotropic effect in rabbit right atria; TS-951 and cisapride at 3 x 10(-5) mol/l reduced the beating rate by about 20 and 40%, respectively. In the sinoatrial node preparations, TS-951 (3 x 10(-5) mol/l) as well as cisapride (10(-6) mol/l) prolonged cycle length and APD and reduced the diastolic depolarization rate. These results indicate that TS-951 does not appear to possess electrophysiological features leading to cardiotoxicity such as QT prolongation and, thus, torsades de pointes in common with cisapride.
Action Potentials↗
Pharmacological characterization of a novel 5-HT4 receptor agonist, TS-951, in vitro.
The pharmacological effect of a novel selective 5-HT4 receptor agonist, TS-951 (N-[endo-8-(3-hydroxypropyl)-8-azabicyclo[3.2.1]oct-3-yl]-1-isopropyl-2-oxo-1,2-dihydro-3-quinolinecarboxamide) was investigated in vitro. TS-951 potently inhibited specific [3H]GR113808 binding both in guinea-pig striatum and in mouse brain. The affinity of TS-951 for the 5-HT4 receptor was higher than those of other agonists, 5-HT, cisapride, mosapride and renzapride. On the longitudinal muscle of the guinea-pig ileum, TS-951 caused a concentration-dependent increase in the amplitude of electrically induced submaximal twitch contractions. On the longitudinal muscle of the guinea-pig distal colon, TS-951 also caused concentration-dependent contractions. TS-951 is a high-affinity, selective and potent 5-HT4 receptor agonist. This compound therefore can be considered as a useful pharmacological tool for investigating 5-HT4 receptor-mediated events.
Animals↗
Synthesis and evaluation of novel 2-oxo-1,2-dihydro-3-quinolinecarboxamide derivatives as potent and selective serotonin 5-HT4 receptor agonists.
A series of 8'-substituted N-(endo-8-azabicyclo[3.2.1]oct-3-yl)-1-isopropyl-2-oxo-1,2-dihydro-3-quinolinecarboxamides were synthesized. The 5-HT4 receptor agonistic activity was evaluated using the isolated guinea pig ileum preparation. Of the compounds synthesized, N-(endo-8-(3-hydroxypropyl)-8-azabicyclo[3.2.1]oct-3-yl)-1-isopropyl-2-oxo-1,2-dihydro-3-quinolinecarboxamide (15a, TS-951) exhibited the most potent serotonin 5-HT4 receptor agonistic activity. This compound had a high affinity for the serotonin 5-HT4 receptor although it had no affinities for other broad spectrum receptors. Furthermore, it remarkably enhanced gastrointestinal motility in conscious fed dogs without unfavorable effects that non-selective serotonin 5-HT4 receptor agonist has. TS-951 may be useful in improving gastrointestinal dysfunction.
Amides↗
Properties of an extracellular polysaccharide produced by a strain of enterobacter isolated from pond water.
A bacterium which was isolated from pond water and identified as Enterobacter cloacae produced a viscous extracellular polysaccharide when it was grown aerobically in a medium containing sucrose as a sole source of carbon. The maximum molecular weight of the polysaccharide was about 9.0 x 10(5). The polysaccharide was composed of fucose, galactose, glucose, and glucuronic acid in a molar ratio of 2:3:2:1, but the molecular weight and the molar ratio of the sugar component were different from those of the polysaccharide produced by the same species reported elsewhere.
Chromatography, Gas↗
Improving the freeze tolerance of bakers' yeast by loading with trehalose.
We examined the freeze tolerance of bakers' yeast loaded with exogenous trehalose. Freeze-tolerant and freeze-sensitive compressed bakers' yeast samples were soaked at several temperatures in 0.5 M and 1 M trehalose and analyzed. The intracellular trehalose contents in both types of bakers' yeast increased with increasing soaking period. The initial trehalose-accumulation rate increased with increasing exogenous trehalose concentration and soaking temperature. The maximum trehalose content was almost identical (200-250 mg/g of dry cells) irrespective of the soaking temperature and the type of bakers' yeast, but depended on the exogenous trehalose concentration. The leavening ability of both types of bakers' yeast loaded with trehalose was almost identical to that of the respective original cells, irrespective of the soaking conditions. The freeze-tolerant ratio (FTR) of both types of bakers' yeast increased with increasing intracellular trehalose content. However, FTR decreased during over-soaking after the maximum amount of trehalose had accumulated. FTR of the freeze-sensitive bakers' yeast was more efficiently improved than that of the freeze-tolerant type.
Freezing↗
Ureteral fibroepithelial polyp associated with urolithiasis induced by steroid therapy in a child: a case report.
A 14-year-old boy complained of left flank pain. He had been given high-dose corticosteroid therapy for chronic inflammatory demyelinating polyneuropathy (CIDP). Retrograde pyelography revealed irregular defects at the left ureteropelvic junction (UPJ), and ureteroscopy demonstrated ureteral polyp. The polyp was removed and histologically diagnosed as fibroepithelial polyp. Hypercalciuria due to the corticosteroids and bedridden was assumed to have been a causative factor in the stone formation. To our knowledge, this is the first report of a ureteral fibroepithelial polyp in children associated with urolithiasis, and associated with CIDP.
Adolescent↗
Synthesis and biological evaluation of CX-659S and its related compounds for their inhibitory effects on the delayed-type hypersensitivity reaction.
In order to find novel nonsteroidal compounds possessing an inhibitory activity against delayed-type hypersensitivity (DTH) reactions, we conducted random screening using a picryl chloride (PC)-induced contact hypersensitivity reaction (CHR) in mice, and found compound 1 as a lead compound. Then we synthesized and evaluated an extensive series of 5-carboxamidouracil derivatives focused on both the uracil and the antioxidative moieties. Among them, we found that the hindered phenol moiety was necessary to exhibit the activities; especially, compounds 28a-28c having the partial structure of vitamin E were found to exert potent activities against the DTH reaction by both oral and topical administration. And compound 28c showed antioxidative activity against lipid peroxidation with an IC50 of 5.9 microM. Compound 28c (CX-659S) was chosen as a candidate drug for the treatment of cutaneous disorders such as atopic dermatitis and allergic contact dermatitis.
Animals↗
CD56 and terminal deoxynucleotidyl transferase positive cutaneous lymphoblastic lymphoma.
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Adult↗
Synthesis and evaluation of novel 2-oxo-1,2-dihydro-3-quinolinecarboxamide derivatives as serotonin 5-HT4 receptor agonists.
A series of N-azabicycloalkyl-1-alkyl-2-oxo-1,2-dihydro-3-quinolinecarboxamides were synthesized and tested for serotonin 5-HT4 receptor-stimulating effects in the regulation of electrically-evoked contraction in guinea pig muscle. Among them, N-azabicycloalkyl-1-isopropyl-2-oxo-1,2-dihydro-3-quinolinecarboxamide (8c, 9c, 10c, 11c, 12c) exhibited potent serotonin 5-HT4 receptor-stimulating activity. The most potent compound, N-(endo-8-methyl-8-azabicyclo[3.2.1 oct-3-yl)-1-isopropyl-2-oxo-1,2-dihydro-3-quinolinecarboxamide (8c, ED50 = 36.3 nMi), was seven times as active as cisapride, while 8c had no affinity for 5-HT1A, 5-HT1D, D2, muscarinic M2 or muscarinic M3 receptors even at 10 microM. Compound 8c stimulated digestive tract motility in conscious fed dogs (1.0 mg/kg p.o.).
Animals↗