• Progress in Medical Physics
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• v.13 no.3
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• pp.120-128
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• 2002

To investigate differences between the metabolic ratios of normal controls and brain tumors such as astrocytomas and glioblastoma multiforme (GM) by proton MR spectroscopy (MRS) at 37 high field system. Using 3T MRI/MRS system, localized water-suppressed single-voxel technique in patients with brain tumors was employed to evaluate spectra with peaks of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine/phosphocreatine (Cr) and lactate. On the basis of Cr, these peak areas were quantificated as a relative ratio. The variation of metabolites measurements of the designated region in 10 normal volunteers was less than 10%. Normal ranges of NAA/Cr and Cho/Cr ratios were 1.67$\pm$018 and 1.16$\pm$0.15, respectively. NAA/Cr ratio of all tumor tissues was significantly lower than that of the normal tissues (P=0.005). Cho/Cr ratio of glioblastoma multiforme was significantly higher than that of astrocytomas (P=0.001). Lactate was observed in all tumor cases. The present study demonstrated that the neuronal degradation or loss was observed in all tumor tissues. Higher grade of brain tumors was correlated with higher Cho/Cr ratio, indicating a significant dependence of Cho levels on malignancy of gliomas. This results suggest that clinical proton MR spectroscopy could be useful to predict tumor malignancy.

• Journal of the Korean Society of Radiology
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• v.9 no.1
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• pp.47-53
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• 2015

Quantitative analysis of MR spectrum depending on mole concentration of the contrast media in cereberal metabolite phantom was performed. PRESS pulse sequence was used to obtain MR spectrum at 3.0T MRI system (Archieva, Philips Healthcare, Best, Netherland), and the phantom contains brain metabolites such as N-Acetyl Asparatate (NAA), Choline (Cho), Creatine (Cr) and Lactate (Lac). In this study, optimization of MRS PRESS pulse sequency depending on the concentration of contrast media (0, 0.1 and $0.3mmol/{\ell}$) was evaluated for various repetition time(TR; 1500, 1700 and 2000 ms). In control (cotrast-media-free) group, NAA and Cho signals were the highest at TR 2000 ms than at 1700 and 1500 ms. Cr had the highest peak signal at TR 1500 ms. When concentration of contrast media was $0.1mmol/{\ell}$, the metabolites were increased NAA 73%, Cho 249%, Cr 37% at TR 1700 ms compared with other TR, and also signal increased at $0.3mmol/{\ell}$, In $0.5mmol/{\ell}$ of contrast agent, cerebral metabolite peaks reduced, especially when TR 1500 ms and 2000 ms they decreased below those of control group. The ratio of metabolite peaks such as NAA/Cr and Cho/Cr decreased as the concentration of the contrast agent increased from 0.1 to $0.5mmol/{\ell}$. Authors found that the optimization of PRESS sequence for 0.3T MRS was as follows: low density of contrast agent ($0.1mmol/{\ell}$ and $0.3mmol/{\ell}$) made the highest signal intensity, while high density of contrast agent reveals the least reduction of signal intensity at 1700 ms. In conclusion, authors believe that it is helpful to reduce TR for acquiring maximum signal intensity.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.237-251
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• 2002

The recent progress on metabolic systems engineering was reviewed based on our recent research results in terms of (1) metabolic signal flow diagram approach, (2) metabolic flux analysis (MFA) in particular with intracellular isotopomer distribution using NMR and/or GC-MS, (3) synthesis and optimization of metabolic flux distribution (MFD), (4) modification of MFD by gene manipulation and by controlling culture environment, (5) metabolic control analysis (MCA), (6) design of metabolic regulation structure, and (7) identification of unknown pathways with isotope tracing by NMR. The main characteristics of metabolic engineering is to treat metabolism as a network or entirety instead of individual reactions. The applications were made for poly-3-hydroxybutyrate (PHB) production using Ralstonia eutropha and recombinant Escherichia coli, lactate production by recombinant Saccharomyces cerevisiae, pyruvate production by vitamin auxotrophic yeast Toluropsis glabrata, lysine production using Corynebacterium glutamicum, and energetic analysis of photosynthesic microorganisms such as Cyanobateria. The characteristics of each approach were reviewed with their applications. The approach based on isotope labeling experiments gives reliable and quantitative results for metabolic flux analysis. It should be recognized that the next stage should be toward the investigation of metabolic flux analysis with gene and protein expressions to uncover the metabolic regulation in relation to genetic modification and/ or the change in the culture condition.

• Biomolecules & Therapeutics
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• v.20 no.4
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• pp.399-405
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• 2012

Silver nanoparticles (AgNPs) are widely used nanoparticles and they are mainly used in antibacterial and personal care products. In this study, we evaluated the effect of AgNPs on cell death induction in the murine dendritic cell line DC2.4. DC2.4 cells exposed to AgNPs showed a marked decrease in cell viability and an induction of lactate dehydrogenase (LDH) leakage in a time- and dose-dependent manner. In addition, AgNPs promoted reactive oxygen species (ROS)-dependent apoptosis and AgNP-induced ROS triggered a decrease in mitochondrial membrane potential. The activation of the intracellular signal transduction pathway was also observed in cells cultured with AgNPs. Taken together, our data demonstrate that AgNPs are able to induce a cytotoxic effect in DCs through ROS generation. This study provides important information about the safety of AgNPs that may help in guiding the development of nanotechnology applications.

• Journal of the Korean Magnetic Resonance Society
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• v.5 no.2
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• pp.99-109
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• 2001

Authors investigated neuronal changes of local cellular metabolism in the cerebral lesions of Parkinsonian symptomatic side between before and after stereotactic neurosurgery by follow-up 1H magnetic resonance spectroscopy (MRS). Patients with Parkinson's disease (PD) (n = 15) and age-matched normal controls (n = 15) underwen MRS examinations using a stimulated echo acquisition mode (STEAM) pulse sequence that provided 2${\times}$2${\times}$2 ㎤ (8ml) volume of interest in the regions of substantia nigra, thalamus, and lentiform nucleus. Spectral parameters were 20 ms TE, 2000 ms TR, 128 averages,2500 Hz spectral width, and 2048 data points. Raw data were processed by the SAGE data analysis package (GE Medical Systems). Peak areas of N-acetylaspartate (NAA), creatine (Cr), choline-containing compounds (Cho), inositols (Ins), and the sum (Glx) of glutamate and GABA were calculated by means of fitting the spectrum to a summation of Lorentzian curves using Marquardt algorithm. After blindly processed, we evaluated neuronal alterations of observable metabolite ratios between before and after stereotactic neurosurgery using Pearson product-moment analysis (SPSS, Ver. 6.0). A significant reduction of NAA/Cho ratio was observed in the cerebral lesion in substantia nigra of PD patient related to the symptomatic side after neurosurgery (P : 0.03). In thalamus, NAA/Cho ratio was also significantly decreased in the cerebral lesion including the electrode-surgical region (P : 0.03). A significant reduction of NAA/Cho ratio in lentiform nucleus was not oberved, but tended toward significant reduction after neurosurgery (P = 0.08). In particular, remarkable lactate signal was noted from the surgical thalamic lesions of 6 among 8 patients and internal segments of globus pallidus of 6 among 7 patients, respectively. Significant metabolic alterations of NAA/Cho ratio might reflect functional changes of neuropathological processes in the lesion of substantia nigra, thalamus, and lentiform nucleus, and could be a valuable finding fur evaluation of Parkinson's disease after neurosurgery. Increase of lactate signals, being remarkable in surgical lesions, could be consistent with a common consequence of neurosurgical necrosis. Thus, IH MRS could be a useful modality to evaluate the diagnostic and prognostic implications fur Parkinsons disease after functional neurosurgery.

• Biomedical Science Letters
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• v.11 no.3
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• pp.319-326
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• 2005

It is well known that oxidative stress of reactive oxygen species (ROS) may be a causative factor in the pathenogenesis of bone disorder on osteoblast or osteoclast. The purpose of this study was to evaluate the cytotoxicity of oxidative stress, protective effect of glutamate receptor antagoinst against ROS-induced osteotoxicity, secretion of tumor necrosis factor $(TNF)-\alpha$ and the expression of c-fos gene in the cultured rat osteoblasts and osteoclasts. Cell viability by MTS assay or !NT assay, activity of glutathione peroxidase (GPx), lipid peroxidation (LPO) activity, protein synthesis by sulforhodamine B (SRB) assay, alkaline phosphatase (ALP) activity, lactate dehydrogenase (LDH) activity, MTS assay for NMDA (N-methyl-D-aspartate) receptor antagonist or AMPA/kainate receptor antagonist, measurement for $TNF-\alpha$, and c-fos gene expression were performed after these cells were treated with or without various cocentrations of xanthine oxidase (XO), hypoxanthine (HX), D-2-amino-5-phosphonovaleric acid (APV), 7-chlorokynurenic acid (CKA), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 6,7-dinitroquinoxaline-2,3-dione (DNQX), respectively. In this study, XO/HX showed decreased cell viability and glutathione peroxidase (GPx) activity, but it showed increased LPO activity, $TNF-\alpha$ secretion and c-fos expression. APV and CKA incresed protein sythesis and ALP activity. While, CNQX or DNQX did not show any protective effect in LDH activity or cell viability. From these results, XO/HX showed cytotoxic effect in cultured rat osteoblast or osteoclast, and also NMDA receptor antagonist such as APV or CKA was effective in blocking XO/HX-induced osteotoxicity in these cultures.

• Journal of Applied Biological Chemistry
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• v.63 no.2
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• pp.137-145
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• 2020

Oxidative stress is one of the pathogenic mechanisms of various neurodegenerative diseases, such as Alzheimer's disease. Neuroglia, the most abundant cells in the brain, is thought to play an important role in the antioxidant defense system and neuronal metabolic support against neurotoxicity and oxidative stress. We investigated the protective effect of paeoniflorin (PF) against oxidative stress in C6 glial cells. Exposure of C6 glial cells to hydrogen peroxide (H₂O₂, 500 μM) significantly decreased cell viability and increased amounts of lactate dehydrogenase (LDH) release, indicating H₂O₂-induced cellular damage. However, treatment with PF significantly attenuated H₂O₂-induced cell death as shown by increased cell survival and decreased LDH release. The H₂O₂-stimulated reactive oxygen species production was also suppressed, and it may be associated with improvement of superoxide dismutase activity by treatment with PF. In addition, an increase in ratio of Bcl-2/Bax protein expression was observed after treatment with PF. In particular, the down-stream of the apoptotic signaling pathway was inhibited in the presence of PF, mostly by reduction of cleaved-poly ADP ribose polymerase, cleaved caspase-3, and -9 protein expression. Furthermore, H₂O₂-induced phosphorylation of c-Jun N-terminal kinase and extracellular signal-regulated kinase 1/2 was attenuated by treatment with PF. Taken together, neuroprotective effect of PF against oxidative stress probably result from the regulation of apoptotic pathway in C6 glial cells. In conclusion, our findings suggest that PF may be a potent therapeutic agent for neurodegenerative disorders.

• Biomolecules & Therapeutics
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• v.27 no.4
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• pp.363-372
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• 2019

Daidzein isolated from soybean (Glycine max) has been widely studied for its antioxidant and anti-inflammatory activities. However, the protective effects of 7,8,4'-trihydroxyisoflavone (THIF), a major metabolite of daidzein, on 6-hydroxydopamine (OHDA)-induced neurotoxicity are not well understood. In the current study, 7,8,4'-THIF significantly inhibited neuronal cell death and lactate dehydrogenase (LDH) release induced by 6-OHDA in SH-SY5Y cells, which were used as an in vitro model of Parkinson's disease (PD). Moreover, pretreatment with 7,8,4'-THIF significantly increased the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) and decreased malondialdehyde (MDA) activity in 6-OHDA-induced SH-SY5Y cells. In addition, 7,8,4'-THIF significantly recovered 6-OHDA-induced cleaved caspase-3, cleaved caspase-9, cleaved poly-ADP-ribose polymerase (PARP), increased Bax, and decreased Bcl-2 levels. Additionally, 7,8,4'-THIF significantly restored the expression levels of phosphorylated c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase 1/2 (ERK 1/2), phosphatidylinositol 3-kinases (PI3K)/Akt, and glycogen synthase kinase-3 beta ($GSK-3{\beta}$) in 6-OHDA-induced SH-SY5Y cells. Further, 7,8,4'-THIF significantly increased the reduced tyrosine hydroxylase (TH) level induced by 6-OHDA in SH-SY5Y cells. Collectively, these results suggest that 7,8,4'-THIF protects against 6-OHDA-induced neuronal cell death in cellular PD models. Also, these effects are mediated partly by inhibiting activation of the MAPK and PI3K/Akt/$GSK-3{\beta}$ pathways.

• Journal of Life Science
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• v.26 no.7
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• pp.764-771
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• 2016

Extracts from Artemisia annua Linné (AAE) have been known to possess various functions, including anti-bacterial, anti-virus, and anti-oxidant effects. However, the mechanism of those effects of AAE is not well-known. The aim of this study was to analyze the inhibitory effects of AAE on cell proliferation of the human hepatoma cell line (Hep3B) and to examine its effects on apoptosis. Activation by phosphorylation of Akt is cell proliferation through the phosphorylation of TSC2, mTOR, and GSK-3β. We suggested that AAE may exert cancer cell apoptosis through Akt/mTOR/GSK-3β signal pathways and mitochondria-mediated apoptotic proteins. For this, we examined the effects of extracts of AAE on cell proliferation according to treatment concentration. Treatment with AAE not only reduced cell viability, but also resulted in the induced release of lactate dehydrogenase (LDH). These results were determined with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and a lactate dehydrogenase (LDH) assay. Furthermore, we determined the effects of apoptosis through Hoechst 33342 staining, annexinⅤ-propidium iodide (PI) staining, 5,5′, 6,6′-tetrachloro-1,1′,3,3′-tetraethyl-imidacarbocyanine iodide (JC-1) staining, and Western blotting. Our study showed that the treatment of liver cancer cells with AAE resulted in the inhibition of Akt, TSC2, GSK-3β-phosphorylated, Bcl-2, and pro-caspase 3 and the activation of Bim, Bax, Bak, and cleaved PARP expressions. These results indicate that AAE induced apoptosis by means of a mitochondrial event through the regulate of Akt/mTOR/GSK-3β signaling pathways.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.483-489
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• 2005

To understand the molecular mechanisms that regulate intramuscular fat deposition and its release, cDNA clones expressed in adipose tissues of Korean cattle were identified by differential screening from adipose tissue cDNA library. By partial nucleotide sequencing of 486 clones and a search for sequence similarity in NCBI nucleotide databases, 245 clones revealed unique clones. By a functional grouping of the clones, 14% of the clones were categorized to metabolism and enzyme-related group (stearoyl CoA desaturase, lactate dehydrogenase, fatty acid synthase, ATP citrate lyase, lipoprotein lipase, acetyl CoA synthetase, etc), and 6% to signal transduction/cell cycle-related group (C/EBP, cAMP-regulated phosphoprotein, calmodulin, cyclin G1, cyclin H, etc), and 4% to cytoskeleton and extracellular matrix components (vimentin, ankyrin 2, gelosin, syntenin, talin, prefoldin 5). The obtained 245 clones will be useful to study lipid metabolism and signal transduction pathway in adipose tissues and to study obesity in human. Some clones were subjected to full-sequencing containing open reading frame. The cDNA clone of bovine homolog of human prefoldin 5 gene had a total length of 959 nucleotides coding for 139 amino acids. Comparison of the deduced amino acid sequences of bovine prefoldin 5 with those of human and mouse showed over 95% identity. The cDNA clone of bovine homolog of human ubiquitin-like/S30 ribosomal fusion protein gene had a total length of 484 nucleotides coding for 133 amino acids. Comparison of the deduced amino acid sequences of bovine ubiquitin-like/S30 ribosomal fusion protein gene with those of human, rat and mouse showed over 97% identity. The cDNA clone of bovine homolog of human proteolipid protein 2 mRNA had a total length of 928 nucleotides coding for 152 amino acids. Comparison of the deduced amino acid sequences of bovine proteolipid protein 2 with those of human and mouse showed 87.5% similarity. The cDNA clone of bovine homolog of rat thymosin beta 4 had a total length of 602 nucleotides coding for 44 amino acids. Comparison of the deduced amino acid sequences of bovine thymosin beta 4 gene with those of human, mouse and rat showed 93.1% similarity. The cDNA clone of bovine homolog of human myotrophin mRNA had a total length of 790 nucleotides coding for 118 amino acids. Comparison of the deduced amino acid sequences of bovine myotrophin gene with those of human, mouse and rat showed 83.9% similarity. The functional role of these clones in adipose tissues needs to be established.