Publications by authors named "Masaaki Akagi"

The contribution of caspases to hepatic ischemia/reperfusion (I/R)-induced apoptosis has not been completely understood yet. Several studies have demonstrated increased caspase activity during I/R and the protective effect of caspase inhibitors against I/R injuries. However, reports with opposing results also exist.

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Magnolol is the main constituent of Magnolia bark and has been reported to exhibit antidepressant effects in rodent models. Hippocampal neurogenesis and neurotrophins such as brain-derived neurotrophic factor are integrally involved in the action of conventional antidepressants. Here, we investigated the effects of magnolol on depressive behaviours, impaired hippocampal neurogenesis and neurotrophin-related signal transduction in an olfactory bulbectomy (OBX) mouse model of depression.

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In this study we investigated the effect of free heme, the local level of which was increased by bleeding, on the intestinal barrier function, using human epithelial colorectal adenocarcinoma cells (Caco-2). Our results show that the addition of hemin to the culture medium markedly disrupted the barrier function, which was significantly improved by glutamine supplementation. Although hemin treatment caused the increased expression of heme oxygenase (HO)-1, the inhibition of HO activity resulted in the aggravation of hemin-induced barrier dysfunction.

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Mast cells are well established effector cells of type I hypersensitivity reactions such as allergic rhinitis. However, recent studies have suggested that activated mast cells enhance local immunoglobulin E (IgE) synthesis in the nasal mucosa of allergic rhinitis patients. Therefore, we hypothesized that non-immunological mast cell activators may have the potential to enhance local IgE synthesis.

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Developed regions, including Japan, have become "aged societies," and the number of adults with senile dementias, such as Alzheimer's disease (AD), Parkinson's disease, and Huntington's disease, has also increased in such regions. Neurotrophins (NTs) may play a role in the treatment of AD because endogenous neurotrophic factors (NFs) prevent neuronal death. However, peptidyl compounds have been unable to cross the blood-brain barrier in clinical studies.

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Resveratrol was glucosylated to its 3- and 4'-β-glucosides by cultured cells of Phytolacca americana. On the other hand, cultured P. americana cells glucosylated pterostilbene to its 4'-β-glucoside.

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β-Hexosaminidase, which is generally present in the lysosome, is essential for glycoprotein metabolism in the maintenance of cell homeostasis. In mast cells (MCs), large amounts of β-hexosaminidase are present in the granules as opposed to the lysosome, and the biological role of MC β-hexosaminidase has yet to be fully elucidated. Therefore, we investigated the biological role of β-hexosaminidase in MC granules.

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While gene knockout technology can reveal the roles of proteins in cellular functions, including in mast cells, fetal death due to gene manipulation frequently interrupts experimental analysis. We generated mast cells from mouse fetal liver (FLMC), and compared the fundamental functions of FLMC with those of bone marrow-derived mouse mast cells (BMMC). Under electron microscopy, numerous small and electron-dense granules were observed in FLMC.

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Three new compounds, 1-3, together with 22 known compounds, were isolated from the fruits of Piper retrofractum. The structures of the new compounds were elucidated on the basis of spectroscopic data analysis and comparison with literature values. Compound 1 was found to enhance the neurite outgrowth of NGF-mediated PC12 cells at concentrations ranging from 0.

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Trans-3-(3'4'-dimethoxyphenyl)-4-[(E)-3",4"-dimethoxystyryl]cyclohex-1-ene (Comp.1) and cis-3-(3'4'-dimethoxyphenyl)-4-[(E)-3",4"-dimethoxystyryl]cyclohex-1-ene (Comp.2), phenylbutenoid dimers, have been isolated as neurotrophic molecules from an Indonesian medicinal plant, Zingiber purpureum.

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To clarify the interaction between hippocampal gamma-aminobutyric acid (GABA)(A) receptor and N-methyl-D-aspartate (NMDA) receptor in the retention of spatial working memory, the effects of muscimol, (+)MK-801, cyclosporin A and combined use of these drugs were studied on the retention of spatial working memory in a delayed spatial win-shift (SWSh) task. Intrahippocampal injection of muscimol at a dose of 3 nmol/side caused a significant decrease in the number of correct choices and an increase in the number of across-phase errors. On the other hand, (+)MK-801 showed no significant effect on the number of correct choices, across-phase errors and within-phase errors, even at a dose of 1.

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The aim of the present study was to clarify the involvement of prostaglandin E(2) (PGE(2)) in nasal congestion in Brown Norway (BN) rats. For this purpose, we studied the effects of PGE(2) receptor (EP(1), EP(2), EP(3) and EP(4)) agonists on nasal congestion and sneezing induced by toluene 2,4-diisocyanate (TDI). Enhanced pause (Penh) was increased 1 h (early phase) and 4 h (late phase) after TDI challenge.

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The present study was undertaken to investigate the characteristics of morphine in rat sleep patterns and also the effects of donepezil and memantine on somnolence caused by morphine. Electrodes were chronically implanted into the cortex and dorsal neck muscle of rats for electroencephalogram (EEG) and electromyogram (EMG) recordings, respectively. EEG and EMG were recorded with an electroencephalograph.

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We studied the effect of Brazilian propolis on sneezing and nasal rubbing in experimental allergic rhinitis of mice. A single administration of propolis caused no significant effect on both antigen-induced nasal rubbing and sneezing at a dose of 1000 mg/kg, but a significant inhibition was observed after repeated administration for 2 weeks at this dose. Propolis caused no significant inhibitory effect on the production of total IgE level after repeated administration of 1000 mg/kg.

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Purpose: The present study was undertaken to clarify the behavioral and electroencephalographic characteristics of olfactory bulb (OB) kindling in rats, in comparison with those of amygdala (AMG) kindling. In addition, the usefulness of OB kindling as a model to evaluate antiepileptics was studied.

Methods: Bipolar electrical stimulation was applied to the OB or AMG every day until generalized seizure was achieved.

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The therapeutic use of neurotrophic factors to treat neurodegenerative disorders, including Alzheimer's disease, is considered feasible. Magnolol and honokiol, constituents of the Magnolia plant, are small organic compounds with neurotrophic activity. We investigated whether magnolol and honokiol can prevent age-related learning and memory impairment and cholinergic deficits in senescence-accelerated mice (SAM).

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The glycosylation of alpha- and delta-tocopherols using Klebsiella pneumoniae and cyclodextrin glucanotransferase (CGTase) was investigated. K. pneumoniae converted alpha- and delta-tocopherols into the corresponding beta-glucosides in 10 and 8% yield, respectively.

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Objectives And Design: We investigated the effects of microbial components on the uptake of microbes by mast cells (MCs), and studied the change in cytokine production in MCs after bacterial uptake.

Material Or Subjects: LAD2 human mast cells, cord-blood and peripheral-blood derived MCs were employed to analyze their surface molecule expression and cytokine generation by flow cytometry. Bacterial internalization in these MCs was observed by confocal microscopy and flow cytometry.

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The aim of this study was to clarify the effect of histamine H(4) receptor antagonist, JNJ7777120 (1-[(5-Chloro-1H-indol-2-yl)carbonyl]-4-methyl-piperazine) on allergic rhinitis in mice. We measured allergic symptoms (sneezing and nasal rubbing), serum total IgE and the levels of cytokines in nasal lavage fluid. Histamine H(4) receptor antagonist, JNJ7777120, caused the dose-dependent inhibition of nasal symptoms by single and repeated intranasal administrations; however, JNJ7777120 caused no inhibition of serum total IgE by single and repeated intranasal administrations.

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Venom of the Australian ant species Myrmecia pilosula contains a number of allergenic peptides including pilosulins. To obtain novel cDNA clones that encode the pilosulin-related bioactive peptides, mRNA of M. pilosula species complex was subjected to RT-PCR in which the forward primer corresponds to a nucleotide sequence in the leader sequences of pilosulins.

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The antimicrobial peptide LL-37 is generated from skin keratinocytes during infection of Gram-negative bacteria and exerts a microbicidal effect. LL-37 also causes functional changes in mast cells. Mast cells in the skin are involved in the innate immune system response against microbial infections via Toll-like receptors (TLRs), such as TLR4, which that is known to recognize lipopolysaccharide (LPS), a bacterial component.

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Cultured suspension cells of Eucalyptus perriniana converted exogenously administered alpha-tocopherol into alpha-tocopheryl 6-O-beta-d-glucopyranoside (46mug/gfr. wt of cells) and two biotransformation products: alpha-tocopheryl 6-O-(6-O-beta-d-glucopyranosyl)-beta-d-glucopyranoside (19mug/gfr. wt of cells) and alpha-tocopheryl 6-O-(6-O-alpha-l-rhamnopyranosyl)-beta-d-glucopyranoside (6mug/gfr.

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Background: FcepsilonRI on the surface of mast cells (MCs) plays a central role in allergic responses. Recent evidence shows that exposure to microbial components corresponds with a significant reduction in the risk for allergic diseases. Although many reports suggest that this is due to changes in T-cell functions, how MC functions are altered by bacterial infection remains unknown.

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