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Objective To explore the metabolite profiles of mesenchymal stem cells(MSCs)underwent death using 9.4 T high resolution MR spectroscopy.Methods MSCs were cultured and treated for 6,12 and 24 hours in a stimulated condition which included hypoxia,serum deprivation and changes of microenvironment.Cell death and the mortality was detected by light microscopy,Hocchst staining and flow cytometry analyses.The morality of stem cells was analyzed using one-way analysis of variance (ANOVA).Cell metabolite extraction was prepared by methanol-chloroform(M/C) method and analyzed on a 9.4 T MR device.1H-MR spectroscopy was obtained and the metabolite concentration of each time point was calculated and compared using one way ANOVA,the difference between two groups was analyzed by SNK test.Results Necrosis was the major form of cell death in the built model.The morality of every time sets was 16±4(0 h),658±61 (6 h),1 571 ± 154(12 h) and 2 816± 178(24 h) respectively,and the difference between each groups were statistically significant (F=298.96,P＜0.01).After induced stem cells death for 6,12 and 24 h,the metabolite concentrations at 0.89 ppm was (1.48±0.69),(2.32±0.63)and (2.15±0.45)nmol/mg respectively,and increased compared to thc control[(1.41 ±0.25)nmol/mg]with statistical significance (F=329.57,P＜0.01).The metabolite concentrations at 1.28 ppm was (6.42±0.31),(7.26±0.32)and (7.01 ±0.61)nmol/mg,respectively,and increased compared to the control[(5.76 ±0.74)nmol/mg]with statistical significance (F=19.56,P＜0.01).The metabolite concentrations at 1.60 ppm was (2.36±0.31),(2.29±0.16)and (2.31 ± 0.24) nmol/mg respectively,and increased compared to the control[(1.96 ± 0.27)nmol/mg]with statistical significance (F=4.35,P＜0.05).After induced stem cells death for 12 hours,the metabolite concentrations at 0.89 ppm was increased compared to 6 hours with statistical significance (P＜0.05).The metabolite concentrations at 1.28 ppm was increased compared to 6 hours with statistical significance (P＜0.05).After induced stem cells death for 24 hours,the metabolite concentrations at 0.89 ppm was decreased compared to 12 hours with statistical significance (P＜0.05).Conclusions There are some specific characteristics on MRS of MSCs underwent death,and the fatty acid peak may serve as a biomarker for cell death.
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Objective To conduct a pilot study on genome-wide in vivo protein-RNA interactions in E.coli.Methods Bacterial lysate was treated with RNase before the RNA fragments protected by proteins were extracted from treated lysate and used to construct cDNA library that was applied to high-throughput sequencing .Finally, the transcripts bound by proteins were obtained by bioinformatics analysis .Results A total of 3193 transcripts were obtained , including 2234 mRNAs, 47 sRNAs, 39 tRNAs, 11 rRNAs, and 862 intergenic regions .Conclusion Some information of transcripts interacting with proteins in E.coli is acquired , which will facilitate further studies of protein-RNA interactions .
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The technology of Magnetic Resonance Spectroscopy(MRS) is a newly-developed mean for analyzing some specific nucleus and their compounds making use of the principles of magnetic resonance and the effects of chemical shift. Currently, among MRS applications, proton magnetic resonance spectroscopy (1HMRS) is the most widely applied one developed from single voxel to three-dimensional multi-voxel scanning technique. It provides a lot of important information for clinical studies. This article mainly reviews the methods for absolute quantification measurement of brain metabolites using multi-voxel MRS.
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Objective To evaluate the absolute quantification of brain metabolites concentrations using external standard MRS in acute hypoxia ischemia encephalopathy (HIE) piglet model. Method Eight 7-day-old healthy piglets were subjected to insult of hypoxia ischemia (HI). The animals and an external standard phantom containing detectable metabolites of known concentrations were studied on a 1.5 T GE Signa scanner. The single-voxel proton magnetic resonance spectroscopy (1H-MRS) data were processed using LCModel software, and the quantification of N-acetylaspartate ( NAA), creatine (Cr) and lactate (Lac) were accomplished. Multivariate analysis of variance was performed to compare the NAA, Cr, Lac concentration differences in the brains of piglets pre- and post-HI (0h). In addition, the dynamic changes of brain metabolites concentrations of 2 HIE piglets were observed at the time points of 0 h and 2 h. Results One piglet was excluded because it was over anesthetized to death. Seven piglets' data were analyzed. The concentrations of NAA pre- and post-HI were ( 6. 86 ± 0. 49 ) mmol/kg and ( 5.73 ± 0. 88 ) mmol/kg respectively, they were ( 4. 65 ± 0. 73 ) mmol/kg and ( 4. 40 ± 0. 80 ) mmol/kg for Cr; and were 0. 00 mmol/kg and (0. 43 ± 0. 39) mmol/kg for Lac. After HI, decreased NAA concentration immediately was observed, and it was of statistical significance ( F = 8. 608, P = 0. 013 ). The concentration of Cr was insignificantly decreased ( F = 0. 379, P = 0. 550). The concentration of Lac was increased, and the difference was of statistical significance ( F = 8. 600 ,P = 0. 013 ). Dynamic observation showed a Lac peak immediately after HI and it decreased after 2 h post-HI. Conclusions External standard MRS using LCModel has great value in the quantitative analysis of brain metabolites. The changes of NAA and Lac concentrations are sensitive to reflect the early metabolic change of acute HIE.
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Objective To design and optimize the MRS pulse sequence which used to measure gamma-aminobutyric acid(GABA) in vivo. Methods In-depth research for the MRS sequence was carried out and a theoretical analysis and simulation by software using product-operator algebra for the design and optimization of pulse sequence was discussed. Results Through the simulation of MRUI software, Cr signal at ?3.0 was seen to be suppressed and the weak GABA signal was displayed clearly. Conclusion The sequence was designed and optimized. Method to increase the efficiency and the stability of the measurement was studied. Our research gives theoretical preparation for the coming programming work.