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161.
Da-Jeong Chang Seung-Hun Oh Nayeon Lee Chunggab Choi Iksoo Jeon Hyun Sook Kim Dong Ah Shin Seo Eun Lee Daehong Kim Jihwan Song 《Experimental & molecular medicine》2013,45(11):e53
The transplantation of neural precursor cells (NPCs) is known to be a promising approach to ameliorating behavioral deficits after stroke in a rodent model of middle cerebral artery occlusion (MCAo). Previous studies have shown that transplanted NPCs migrate toward the infarct region, survive and differentiate into mature neurons to some extent. However, the spatiotemporal dynamics of NPC migration following transplantation into stroke animals have yet to be elucidated. In this study, we investigated the fates of human embryonic stem cell (hESC)-derived NPCs (ENStem-A) for 8 weeks following transplantation into the side contralateral to the infarct region using 7.0T animal magnetic resonance imaging (MRI). T2- and T2*-weighted MRI analyses indicated that the migrating cells were clearly detectable at the infarct boundary zone by 1 week, and the intensity of the MRI signals robustly increased within 4 weeks after transplantation. Afterwards, the signals were slightly increased or unchanged. At 8 weeks, we performed Prussian blue staining and immunohistochemical staining using human-specific markers, and found that high percentages of transplanted cells migrated to the infarct boundary. Most of these cells were CXCR4-positive. We also observed that the migrating cells expressed markers for various stages of neural differentiation, including Nestin, Tuj1, NeuN, TH, DARPP-32 and SV38, indicating that the transplanted cells may partially contribute to the reconstruction of the damaged neural tissues after stroke. Interestingly, we found that the extent of gliosis (glial fibrillary acidic protein-positive cells) and apoptosis (TUNEL-positive cells) were significantly decreased in the cell-transplanted group, suggesting that hESC-NPCs have a positive role in reducing glia scar formation and cell death after stroke. No tumors formed in our study. We also performed various behavioral tests, including rotarod, stepping and modified neurological severity score tests, and found that the transplanted animals exhibited significant improvements in sensorimotor functions during the 8 weeks after transplantation. Taken together, these results strongly suggest that hESC-NPCs have the capacity to migrate to the infarct region, form neural tissues efficiently and contribute to behavioral recovery in a rodent model of ischemic stroke. 相似文献
162.
Sung Wook Kang Ok Kyun Kim Bochan Seo Sung Ho Lee Fu Shi Quan Jae Ho Shin Gi-Ja Lee Hun-Kuk Park 《Analytica chimica acta》2013
In this study, we simultaneously measured nitric oxide (NO) and oxygen (O2) dynamics in the myocardium during myocardial ischemia-reperfusion (IR) utilizing sol-gel modified electrochemical NO and O2 microsensors. In addition, we attempted to clarify the correlation between NO release in the ischemic period and O2 restoration in the myocardium after reperfusion, comparing a control heart with a remote ischemic preconditioning (RIPC)-treated heart as an attractive strategy for myocardial protection. Rat hearts were randomly divided into two groups: a control group (n = 5) and an RIPC group (n = 5, with RIPC treatment). Myocardia that underwent RIPC treatment (182 ± 70 nM, p < 0.05) released more NO during the ischemic period than those of the control group (63 ± 41 nM). The restoration value of oxygen tension (pO2) in the RIPC group significantly increased and was restored to pre-ischemic levels (92.6 ± 36.8%); however, the pO2 of the control group did not increase throughout the reperfusion period (5.7 ± 7.5%, p = 0.001). Myocardial infarct size measurements revealed a significant decrease in cell death in the myocardium region of the RIPC group (41.44 ± 6.42%, p = 0.001) compared with the control group (60.05 ± 10.91%). As a result, we showed that the cardioprotective effect of RIPC could be attributed to endogenous NO production during the ischemic period, which subsequently promoted reoxygenation in post-ischemic myocardia during early reperfusion. Our results suggest that the promotion of endogenous formation during an ischemic episode might be helpful as a therapeutic strategy for protecting the myocardium from IR injury. Additionally, our NO and O2 perm-selective microsensors could be utilized to evaluate the effect of drug or treatment. 相似文献
163.
Hiroyuki Ishibashi Iwao Takamuro Yo-Ichi Mizukami Maki Irie Masazumi Ikeda 《合成通讯》2013,43(3-4):443-452
Friedel-Crafts acylation of arenes with methylthio- (1) or phenylthio-acetyl chloride (2) provides ready access to α-methylthio- or α-phenylthio-substituted acetophenones. The acyl chlorides 1 and 2 reacted also with organoaluminum reagents to give α-sulfenylated alkanones. 相似文献
164.
The reaction of ninhydrin with 1,2,3- and 1,2,4-trimethylbenzene in the presence of H2SO4 or AlCl3 afforded 2-monoaryl and 2,2-diaryl-1,3-indanedione derivatives as the major products. With 1,3,5-trimethylbenzene as the arene nucleophile, either a reduction product or an indenoindanone derivative was obtained depending upon the catalyst employed in the reaction. 相似文献
165.
Yuki Yanagisawa Takeshi Kageyama Naohisa Wada Masatoshi Tanaka Shin‐ya Ohno 《Photochemistry and photobiology》2013,89(6):1490-1496
The time‐dependent characteristics of firefly bioluminescence initiated by manual injection of adenosine triphosphate (ATP) into buffer solution containing luciferin (Ln), luciferase (Luc) and Mg2+ were measured with a resolution of 10 ms, and compared with those obtained by photolysis of caged ATP. The time course depends on pH; both rise and decay rates decrease when pH is lowered from 7.8 to 6.8. In contrast, the parameter λ in the kinetic formula related to diffusion of ATP is almost independent of pH. The pH dependence of the time course of bioluminescence can be explained by the same pH tendency as the rate of ATP binding at the active site of Luc. The time‐resolved spectra can be decomposed into two Gaussian components with maxima at 2.2 and 2.0 eV. At pH 7.8, the band at 2.2 eV is more intense than that at 2.0 eV for all three concentration conditions. At lower pH, the band at 2.2 eV becomes weaker than that at 2.0 eV. The intensity ratio of the 2.0 and 2.2 eV bands is constant for duration time of 600 s for both injection and photolysis experiments, and the above conclusions are unaffected by the concentration ratio [Ln]/[Luc]. 相似文献
166.
Yeon‐Ju Lee Dong‐Geun Lee Hyun Soo Rho Vladimir B. Krasokhin Hee Jae Shin Jong Seok Lee Hyi‐Seung Lee 《Journal of heterocyclic chemistry》2013,50(6):1400-1404
Three new 5‐hydroxyindole alkaloids ( 1 , 2 , 3 ) along with seven known analogs ( 4 , 5 , 6 , 7 , 8 , 9 , 10 ) were isolated from a Dokdo marine sponge Scalarispongia sp. The elucidation of the structures of the new compounds by spectroscopic analyses indicated that these compounds were an indole glyoxylate ( 1 ), a mono‐indole analog of hyrtinadine A ( 2 ), and a symmetrical bis‐indole with pyridine linker ( 3 ). The comparison of IC50 values for obtained compounds against a human leukemia cell line revealed that the bis‐indole structure is a requirement for cytotoxicity. 相似文献
167.
Hong WooLee Tae WonKang Eung-Nam Kim Jaewook Shin Kyung HoiCha Dong OckCho 《合成通讯》2013,43(23):4345-4354
A method for preparing cephalosporin derivatives by reacting cephalosporin alkaline metal salts with organic halide in the presence of quarternary ammonium salts catalyst is disclosed. Δ3 to Δ2 isomerization, a side reaction commonly reported in preparation of cephalosporin derivatives, was successfully eliminated. The desired Δ3 was obtained as a sole product in the reaction. 相似文献
168.
169.
Pradip K. Bhowmik Haesook Han Ivan K. Ndedeltchev James J. Cebe Shin‐Woong Kang Satyendra Kumar 《Liquid crystals》2013,40(8):891-906
Several viologen bis{tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate} salts were prepared by metathesis reaction of the corresponding viologen dibromides (diiodide) with sodium bis{tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate} salt in a polar organic solvent. They were characterized for their physical and thermal properties by experimental techniques including variable temperature X‐ray diffraction. All exhibited low T g and T m, and their T g/T m (K) ratios were in the range 0.66–0.79. Several exhibited polymorphism and formed isotropic ionic melts at <150°C. They were soluble in many common organic solvents such as ethers, alcohols, acetonitrile and methylene chloride. They exhibited photoluminescence in both 1,2‐dimethoxyethane and methanol, as well as in the solid state. In the solid state, the emission spectra exhibited hypsochromic shift when compared with those in solutions of 1,2‐dimethoxyethane and methanol. 相似文献
170.
Chong-Kwang Lee Corresponding author Soon-Sik Kwon Tae-Sung Kim E-Joon Choi Sung-Tae Shin Wang-Cheol Zin 《Liquid crystals》2013,40(12):1401-1406
New chiral bent-core mesogens, derivatives of 1,3-phenylene bis[4-(alkanyloxyphenyliminomethyl)benzoate], were synthesized with variation of a substituent (X=F, Cl); their antiferroelectric properties are described. The mesomorphic and switching properties were characterized by differential scanning calorimetry, polarizing optical microscopy, triangular wave method, and X-ray diffractometry in the small and wide angle regions. The presence of chiral tails at the terminals of side wings in the bent-core molecules induced a decrease in transition temperature and formation of the switchable SmC* phase in the melt. In addition, the introduction of a lateral halogen substituent in the Schiff's base moiety prevented the regular stacking of the molecules, resulting in the formation of very complex optical textures. The smectic phase with F-substituted PBFDOB and Cl-substituted PBCDOB showed layer spacings of 39 and 38.5?Å, respectively, corresponding to the end-to-end distance of molecules with a bent conformation. Significantly, the smectic phases of PBFDOB and PBCDOB exhibited a period of 179.5 and 131?Å, respectively, compatible with a helical structure with periodicity about 4.6 and 3.4 times the layer spacings. 相似文献