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Search Results: 1 - 10 of 1340 matches for " Yuji Tohda "
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Simple HPLC Analysis of Hinokitiol in Skin Lotion with Visible Light Detection after Pre-Column Dabsylation  [PDF]
Yasuhiko Higashi, Shunsuke Tohda
American Journal of Analytical Chemistry (AJAC) , 2017, DOI: 10.4236/ajac.2017.85026
Abstract: Hinokitiolis frequently added to personal care products as an antibacterial agent. We previously established an HPLC-UV method for determination of hinokitiol in skin lotion after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole. However, the labeling reagent is expensive, and derivatives of degradation products of parabens, which may be added to skin lotion as general preservatives, interfered with the peak of the hinokitiol derivative. In this study, the concentration of hinokitiol in skin lotions was determined by HPLC with a visible light detector (450 nm) after pre-column derivatization with 4-(dimethylamino)azobenzene-4’-sulfonyl chloride (Dabsyl-Cl), a more economical reagent. A standard curve was obtained after derivatization with Dabsyl-Cl in borate buffer (pH 9.5) at 55°C for 10 min. The retention time of Dabsyl-hinokitiol was 6.8 min. The calibration plot was linear in the range of 1.25 to 40 μg/mL with a r2 value of 0.9991, and the lower limit of quantification and detection were 0.60 μg/mL (absolute amount of 0.86 ng/20μL injection, signal-to-noise ratio of 10:1) and 0.18 μg/mL (absolute amount of 0.26 ng/20μL injection, signal-to-noise ratio of 3:1), respectively. The coefficient of variation was less than 8.8%. Seven Dabsyl-paraben derivatives showed little interference with the peak of Dabsyl-hinokitiol. The developed system was used to determine the content of hinokitiol in two skin lotions. Addition-recovery tests gave satisfactory results.
STAT6 expression in T cells, alveolar macrophages and bronchial biopsies of normal and asthmatic subjects
Katsuyuki Tomita, Gaetano Caramori, Kazuhiro Ito, Hiroyuki Sano, Sam Lim, Timothy Oates, Borja Cosio, K Fan Chung, Yuji Tohda, Peter J Barnes, Ian M Adcock
Journal of Inflammation , 2012, DOI: 10.1186/1476-9255-9-5
Abstract: We have investigated the expression of STAT6 in peripheral blood T-lymphocytes, alveolar macrophages and bronchial biopsies from 17 normal subjects and 18 mild-moderate steroid-na?ve stable asthmatic patients.STAT6 expression was variable and was detected in T-lymphocytes, macrophages and bronchial epithelial cells from all subjects with no difference between normal and stable asthmatic subjects.STAT6 expression in different cells suggests that it may be important in regulating the expression of not only Th2-like cytokines in T cells of man, but may also regulate STAT-inducible genes in alveolar macrophages and airway epithelial cells.Asthma is characterised by chronic airway inflammation, with infiltration of T-lymphocytes, mast cells, eosinophils and monocytes/macrophages. This is associated with the increased expression of several inflammatory proteins, including cytokines, enzymes, receptors and adhesion molecules [1]. The molecular pathways involved in the induction of chronic cytokine expression and recruitment to the airways and activation of inflammatory cells in asthma are not well understood. However, there is increasing recognition that these processes involve increased transcription of inflammatory genes, and that this is regulated by transcription factors [1]. Several transcription factors are involved in asthmatic inflammation including nuclear factor-κB (NF-κB) [2,3] and activator protein-1 (AP-1) [4].CD4+ T helper (Th) cells can be divided into four major subsets termed Th1, Th2, Th17 and Th0 based on the pattern of cytokines they produce. More recently, another two subsets of effector CD4+ Th cells, named Th9 and Th22 cells, have been described, even if their pathophysiological meaning is still unclear [5,6]. Th1 cells produce predominantly interferon gamma (IFNγ) and predominantly promote cell-mediated immune responses, whereas Th2 cells, which produce mainly IL-4, IL-5 and IL-13, provide help for some B cell responses. IL-4 and IL-13 in particular
Epimedium koreanum Extract and Its Constituent Icariin Improve Motor Dysfunction in Spinal Cord Injury
Chihiro Tohda,Aiko Nagata
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/731208
Abstract: Although cell transplantation strategies for spinal cord injury (SCI) using sources such as iPS cells and neural stem cells are focused as expectative therapies for SCI, the possibility of medication as more accessible and practical way should not be given up. We, therefore, aimed to develop medical sources for SCI. In this paper, we evaluated effects of a famous tonic herb, Epimedium koreanum, on motor dysfunction in spinal cord injury (SCI). The spinal cord was injured by contusion after laminectomy at T10 level. Oral administration of the methanol extract of E. koreanum significantly enhanced hindlimb function in SCI mice by short period treatment (for initial 3 days) and chronic treatment (21 days), although chronic treatment recovered the function more potently. Since it is well known that icariin is the major constituent in E. koreanum, icariin was administered orally to SCI mice for initial 3 days. Motor dysfunction was ameliorated by icariin treatment similarly to the methanol extract of E. koreanum. This paper is the first report to indicate E. koreanum is effective for recovery of motor function in SCI, and at least icariin is an active constituent.
Evidence of Antidepressive Effects of a Wakan-yaku, Hochuekkito, in Depression Model Mice with Learned-Helplessness Behavior
Michihisa Tohda,Salin Mingmalairak
Evidence-Based Complementary and Alternative Medicine , 2013, DOI: 10.1155/2013/319073
Abstract: Wakan-yaku is a type of Japanese and Sino traditional, systematized medical care that has been practiced for hundreds of years. This medicinal system includes many antidepressive prescriptions. One of the candidates is Hochuekkito, although experimental evidence has not yet been established clearly. To obtain evidence, a depression model of learned-helplessness (LH) mice was used. Based on the score of escape failure, an index of the depression degree, mice with a depressive condition were selected to assess Hochuekkito’s effects. This selection was significant and effective in the following two points: evaluation of the drug effect under disease conditions and minimization of the number of animals. Treatment with Hochuekkito (1 and 5?g/kg p.o.; estimated galenical amount) for 14 days significantly decreased the depression index, the number of escape failures, and desipramine (10?mg/kg p.o.) suggesting that Hochuekkito has an antidepressive effect. 1. Introduction Since the discovery of the antidepressive effect of imipramine in the 1950s, clinical antidepressants have been developed with monoamine transporters as the target molecules [1]. Meanwhile, many “Wakan-yaku prescriptions” have been traditionally used to treat depression. By studying the action mechanism of these Wakan-yaku prescriptions, elucidation of the generation mechanism of depression and the development of new antidepressants are expected; however, there is little experimental evidence for the antidepressive effects of Wakan-yaku. The learned-helplessness (LH) behavior of experimental animals caused by inescapable footshocks is one behavioral phenotype relevant to depression [1, 2]. Since this behavior can be ameliorated by antidepressants, LH animals have been used for studying the pathophysiology of depression and the actions of antidepressants [3, 4]. LH model animals can evaluate a drug effect under more pathological conditions than the forced swimming test and tail suspension test, which are evaluated by correlation. It has been also reported that the forced swimming itself is a strong and sustained stress [5]. Therefore, in this study, the effect of a Wakan-yaku prescription, Hochuekkito, was evaluated using LH mice. Hochuekkito has antidepressant-like effects in the forced swimming test [6]. A description of Hochuekkito (Bu Zhong Yi Qi Tang in Chinese) first appeared in Neiwaishang Bianhuolun, which was written by Dong Yuan Li in 1247. At that time, people living around Li had lost their physical strength because of malnutrition during war; therefore, Li developed Hochuekkito for
On the Generalization of Hilbert’s 17th Problem and Pythagorean Fields  [PDF]
Yuji Shimizuike
Advances in Pure Mathematics (APM) , 2013, DOI: 10.4236/apm.2013.37A001

The notion of preordering, which is a generalization of the notion of ordering, has been introduced by Serre. On the other hand, the notion of round quadratic forms has been introduced by Witt. Based on these ideas, it is here shown that 1) a field F is formally real n-pythagorean iff the nth radical, RnF is a preordering (Theorem 2), and 2) a field F is n-pythagorean iff for any n-fold Pfister form ρ. There exists an odd integer l(>1) such that l×ρ is a round quadratic form (Theorem 8). By considering upper bounds for the number of squares on Pfister’s interpretation, these results finally lead to the main result (Theorem 10) such that the generalization of pythagorean fields coincides with the generalization of Hilbert’s 17th Problem.

Observation of Environmental Stress Cracking in Polymethylmethacrylate by Using the Chemiluminescence Method  [PDF]
Yuji Higuchi
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.611107
Abstract: Polymethylmethacrylate (PMMA) is highly regarded for its transparency, and is used in such products as cameras and Video Tape Recorders as plastic lenses to take advantage of its excellent optical properties. Also, it is used in numerous other industrial fields like automobile lamp lenses, billboards, and lighting equipment. The phenomenon of environmental stress cracking is known to occur in PMMA due to ethanol, and there are cases when this may become a factor which causes damage of molded products. In the present paper, upon close observation by using the method of chemiluminescence in order to elucidate the mechanism by which this environmental stress cracking occurs, we report that we are able to capture the formation of a radical at the moment of cracking.
The Change in Self-Esteem among Middle School Students in Japan, 1989-2002  [PDF]
Yuji Ogihara
Psychology (PSYCH) , 2016, DOI: 10.4236/psych.2016.711136
Abstract: This paper examined temporal changes in self-esteem among middle school students in Japan from 1989 to 2002. Previous research showed that self-esteem decreased among middle school students between 1999 and 2006. However, it was unclear whether such a decrease was also present in other periods of time. To obtain a better understanding of how people adapt to socio-economic environments, it is important to gain a more comprehensive view of such long-term cultural/social changes. Therefore, to supplement the findings of the existing research on changes in self-esteem, we analyzed large-sample time-series data collected in Japan in 1989 and 2002. We found that middle schoolers’ self-esteem decreased from 1989 to 2002, consistent with previous research. Thus, our study extends the previous research by presenting additional data showing the decrease in self-esteem in Japan.
Rheological Behavior of Nanosilica Suspensions in Poly(Ethylene Oxide) Solutions with Sodium Chloride  [PDF]
Yuji Hirose
Materials Sciences and Applications (MSA) , 2017, DOI: 10.4236/msa.2017.85022
Abstract: Suspensions of silica nanoparticles showed shear-thickening profiles under steady shear conditions up on addition of a small amount of poly(ethylene oxide) (PEO). The suspensions turned into gels upon shaking and their fluidity was recovered several minutes after resting. We studied the rheological properties of these shake gels with small amounts of sodium chloride (NaCl). Gelation occurred at lower shear rates upon addition of small amounts of NaCl. In addition, the time taken by the gelated samples to recover their original viscosity increased with the increasing NaCl content. The weakened repulsive interactions between the silica particles upon NaCl addition lead to particles in closer proximity, and three-dimensional networks of PEO chains are easily formed as the electric double layer of the particles becomes thinner.
Orbital Phase Theory and the Diastereoselectivity of Some Organic Reactions  [PDF]
Yuji Naruse
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.67005
The orbital phase refers to the relationship between orbitals that originates from their wave character. We show here that the orbital phase essentially determines the diastereoselectivity of the following three organic reactions. 1) Torquoselectivity of the electrocyclicring-opening reaction of 3-substituted cyclobutenes; 2) Contradictory torquoselectivity of the retro-Nazarov reaction; 3) Diastereoselectivity in electrophilic addition to substituted ethylenes.
Kihi-to, a herbal traditional medicine, improves Abeta(25–35)-induced memory impairment and losses of neurites and synapses
Chihiro Tohda, Rie Naito, Eri Joyashiki
BMC Complementary and Alternative Medicine , 2008, DOI: 10.1186/1472-6882-8-49
Abstract: Effects of Kihi-to, a traditional Japanese-Chinese traditional medicine, on memory deficits and losses of neurites and synapses were examined using Alzheimer's disease model mice. Improvements of Aβ(25–35)-induced neuritic atrophy by Kihi-to and the mechanism were investigated in cultured cortical neurons.Administration of Kihi-to for consecutive 3 days resulted in marked improvements of Aβ(25–35)-induced impairments in memory acquisition, memory retention, and object recognition memory in mice. Immunohistochemical comparisons suggested that Kihi-to attenuated neuritic, synaptic and myelin losses in the cerebral cortex, hippocampus and striatum. Kihi-to also attenuated the calpain increase in the cerebral cortex and hippocampus. When Kihi-to was added to cells 4 days after Aβ(25–35) treatment, axonal and dendritic outgrowths in cultured cortical neurons were restored as demonstrated by extended lengths of phosphorylated neurofilament-H (P-NF-H) and microtubule-associated protein (MAP)2-positive neurites. Aβ(25–35)-induced cell death in cortical culture was also markedly inhibited by Kihi-to. Since NF-H, MAP2 and myelin basic protein (MBP) are substrates of calpain, and calpain is known to be involved in Aβ-induced axonal atrophy, expression levels of calpain and calpastatin were measured. Treatment with Kihi-to inhibited the Aβ(25–35)-evoked increase in the calpain level and decrease in the calpastatin level. In addition, Kihi-to inhibited Aβ(25–35)-induced calcium entry.In conclusion Kihi-to clearly improved the memory impairment and losses of neurites and synapses.Neuronal death, neuritic atrophy, and loss of synapses underlie the pathogenesis of Alzheimer's [1-3]. However, neurons with atrophic neurites may remain viable and have the potential to remodel, even when neuronal death has occurred in other parts of the brain. We previously hypothesized that achievement of recovery of brain function after the injury requires the reconstruction of neuronal networks, inc
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