Publications by authors named "Dae Hee Park"

8 Publications

  • Page 1 of 1

Sublimation of DAN Matrix for the Detection and Visualization of Gangliosides in Rat Brain Tissue for MALDI Imaging Mass Spectrometry.

J Vis Exp 2017 03 23(121). Epub 2017 Mar 23.

Department of Anatomy and Cell Biology, The University of Western Ontario;

Sample preparation is key for optimal detection and visualization of analytes in Matrix-assisted Laser Desorption/Ionization (MALDI) Imaging Mass Spectrometry (IMS) experiments. Determining the appropriate protocol to follow throughout the sample preparation process can be difficult as each step must be optimized to comply with the unique characteristics of the analytes of interest. This process involves not only finding a compatible matrix that can desorb and ionize the molecules of interest efficiently, but also selecting the appropriate matrix deposition technique. For example, a wet matrix deposition technique, which entails dissolving a matrix in solvent, is superior for desorption of most proteins and peptides, whereas dry matrix deposition techniques are particularly effective for ionization of lipids. Sublimation has been reported as a highly efficient method of dry matrix deposition for the detection of lipids in tissue by MALDI IMS due to the homogeneity of matrix crystal deposition and minimal analyte delocalization as compared to many wet deposition methods . Broadly, it involves placing a sample and powdered matrix in a vacuum-sealed chamber with the samples pressed against a cold surface. The apparatus is then lowered into a heated bath (sand or oil), resulting in sublimation of the powdered matrix onto the cooled tissue sample surface. Here we describe a sublimation protocol using 1,5-diaminonaphthalene (DAN) matrix for the detection and visualization of gangliosides in the rat brain using MALDI IMS.
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http://dx.doi.org/10.3791/55254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5408897PMC
March 2017

Increased Expression of GM1 Detected by Electrospray Mass Spectrometry in Rat Primary Embryonic Cortical Neurons Exposed to Glutamate Toxicity.

Anal Chem 2016 08 18;88(15):7844-52. Epub 2016 Jul 18.

Department of Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario , London, Ontario N6A 5A5, Canada.

Neurons within different brain regions have varying levels of vulnerability to external stress and respond differently to injury. A potential reason to explain this may lie within a key lipid class of the cell's plasma membrane called gangliosides. These glycosphingolipid species have been shown to play various roles in the maintenance of neuronal viability. The purpose of this study is to use electrospray ionization mass spectrometry (ESI-MS) and immunohistochemistry to evaluate the temporal expression profiles of gangliosides during the course of neurodegeneration in rat primary cortical neurons exposed to glutamate toxicity. Primary embryonic (E18) rat cortical neurons were cultured to DIV (days in vitro) 14. Glutamate toxicity was induced for 1, 3, 6, and 24 h to injure and kill neurons. Immunofluorescence was used to stain for GM1 and GM3 species, and ESI-MS was used to quantify the ganglioside species expressed within these injured neurons. ESI-MS data revealed that GM1, GM2, and GM3 were up-regulated in neurons exposed to glutamate. Interestingly, using immunofluorescence, we demonstrated that the GM1 increase following glutamate exposure occurred in viable neurons, possibly indicating a potential intrinsic neuroprotective response. To test this potential neuroprotective property, neurons were pretreated with GM1 for 24 h prior to glutamate exposure. Pretreatment with GM1 conferred significant neuroprotection against glutamate-induced cell death. Overall, work from this study validates the use of ESI-MS for cell-derived gangliosides and supports the further development of lipid based strategies to protect against neuron cell death.
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http://dx.doi.org/10.1021/acs.analchem.6b01940DOI Listing
August 2016

Increased Expression of Simple Ganglioside Species GM2 and GM3 Detected by MALDI Imaging Mass Spectrometry in a Combined Rat Model of Aβ Toxicity and Stroke.

PLoS One 2015 18;10(6):e0130364. Epub 2015 Jun 18.

Dept. Anatomy and Cell Biology, Western University, London, ON, N6A 5C1, Canada; Dept. Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, ON, N6A 5A5, Canada.

The aging brain is often characterized by the presence of multiple comorbidities resulting in synergistic damaging effects in the brain as demonstrated through the interaction of Alzheimer's disease (AD) and stroke. Gangliosides, a family of membrane lipids enriched in the central nervous system, may have a mechanistic role in mediating the brain's response to injury as their expression is altered in a number of disease and injury states. Matrix-Assisted Laser Desorption Ionization (MALDI) Imaging Mass Spectrometry (IMS) was used to study the expression of A-series ganglioside species GD1a, GM1, GM2, and GM3 to determine alteration of their expression profiles in the presence of beta-amyloid (Aβ) toxicity in addition to ischemic injury. To model a stroke, rats received a unilateral striatal injection of endothelin-1 (ET-1) (stroke alone group). To model Aβ toxicity, rats received intracerebralventricular (i.c.v.) injections of the toxic 25-35 fragment of the Aβ peptide (Aβ alone group). To model the combination of Aβ toxicity with stroke, rats received both the unilateral ET-1 injection and the bilateral icv injections of Aβ25-35 (combined Aβ/ET-1 group). By 3 d, a significant increase in the simple ganglioside species GM2 was observed in the ischemic brain region of rats who received a stroke (ET-1), with or without Aβ. By 21 d, GM2 levels only remained elevated in the combined Aβ/ET-1 group. GM3 levels however demonstrated a different pattern of expression. By 3 d GM3 was elevated in the ischemic brain region only in the combined Aβ/ET-1 group. By 21 d, GM3 was elevated in the ischemic brain region in both stroke alone and Aβ/ET-1 groups. Overall, results indicate that the accumulation of simple ganglioside species GM2 and GM3 may be indicative of a mechanism of interaction between AD and stroke.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0130364PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4473074PMC
April 2016

Saengmaeksan inhibits inflammatory mediators by suppressing RIP-2/caspase-1 activation.

Immunopharmacol Immunotoxicol 2013 Apr 28;35(2):241-50. Epub 2013 Jan 28.

College of Korean Medicine, Institute of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea.

Background And Objectives: Saengmaeksan (SMS) is a Korean herbal prescription consisting of three different herbal drugs: Liriopis Tuber (tuber of Liriope platyphylla, Liliaceae), Ginseng Radix (root of Panax ginseng) and Schisandrae Fructus (fruit of Schisandra chinensis). SMS is commonly used in Korea to treat various diseases that involve the respiratory and cardiovascular systems. However, to date, the mechanism underlying the anti-inflammatory effects of SMS is not clearly understood. In this study, we attempt to determine the effects of SMS on lipopolysaccharide (LPS)-induced inflammatory responses in mouse peritoneal macrophages.

Methods: Cell viability was measured by using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and nitric oxide (NO) levels were measured by using Griess reagent. The tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels secreted by the cells were measured using a modified enzyme-linked immunosorbent assay. Expression of cyclooxygenase (COX)-2 and nuclear factor-kappa B (NF-κB), respectively was investigated using a western blot analysis. A caspase colorimetric assay kit was used to assay enzymatic caspase-1 activity.

Results: The findings of this study showed that SMS reduced TNF-α and IL-6 production induced by LPS. During the inflammatory process, COX-2 and NO levels were increased in mouse peritoneal macrophages, but SMS decreased the enhanced levels of COX-2 and the production of NO. In addition, SMS suppressed the activation of NF-κB and receptor interacting protein-2/caspase-1.

Discussion And Conclusion: Our results provide novel insights into the pharmacological actions of SMS, a molecule that can potentially be exploited in the treatment of inflammatory diseases.
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http://dx.doi.org/10.3109/08923973.2012.757617DOI Listing
April 2013

Anti-Inflammatory activity of chrysophanol through the suppression of NF-kappaB/caspase-1 activation in vitro and in vivo.

Molecules 2010 Sep 16;15(9):6436-51. Epub 2010 Sep 16.

Department of Pharmacology, College of Oriental Medicine, Institute of Oriental Medicine, Kyung Hee University, Seoul, Korea.

Chrysophanol is a member of the anthraquinone family and has multiple pharmacological effects, but the exact mechanism of the anti-inflammatory effects of chrysophanol has yet to be thoroughly elucidated. In this study, we attempted to determine the effects of chrysophanol on dextran sulfate sodium (DSS)-induced colitis and lipopolysaccharide (LPS)-induced inflammatory responses in mouse peritoneal macrophages. The findings of this study demonstrated that chrysophanol effectively attenuated overall clinical scores as well as various pathological markers of colitis. Additionally, chrysophanol inhibited the production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and the expression of cyclooxygenase (COX)-2 levels induced by LPS. We showed that this anti-inflammatory effect of chrysophanol is through suppression of the activation of NF-kappaB and caspase-1 in LPS-stimulated macrophages. These results provide novel insights into the pharmacological actions of chrysophanol as a potential molecule for use in the treatment of inflammatory diseases.
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http://dx.doi.org/10.3390/molecules15096436DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6257778PMC
September 2010

Estimation of biological oxygen demand and chemical oxygen demand for combined sewer systems using synchronous fluorescence spectra.

Sensors (Basel) 2010 24;10(4):2460-71. Epub 2010 Mar 24.

Department of Earth and Environmental Sciences, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul, 143-747, Korea.

Real-time monitoring of water quality for sewer system is required for efficient sewer network design because it provides information on the precise loading of pollutant to wastewater treatment facilities and the impact of loading on receiving water. In this study, synchronous fluorescence spectra and its first derivatives were investigated using a number of wastewater samples collected in sewer systems in urban and non-urban areas, and the optimum fluorescence feature was explored for the estimation of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations of sewer samples. The temporal variations in BOD and COD showed a regular pattern for urban areas whereas they were relatively irregular for non-urban areas. Irrespective of the sewer pipes and the types of the areas, two distinct peaks were identified from the synchronous fluorescence spectra, which correspond to protein-like fluorescence (PLF) and humic-like fluorescence (HLF), respectively. HLF in sewer samples appears to be associated with fluorescent whitening agents. Five fluorescence characteristics were selected from the synchronous spectra and the first-derivatives. Among the selected fluorescence indices, a peak in the PLF region (i.e., Index I) showed the highest correlation coefficient with both BOD and COD. A multiple regression approach based on suspended solid (SS) and Index I used to compensate for the contribution of SS to BOD and COD revealed an improvement in the estimation capability, showing good correlation coefficients of 0.92 and 0.94 for BOD and COD, respectively.
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http://dx.doi.org/10.3390/s100402460DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3274188PMC
June 2012

Spectroscopic and chromatographic characterization of wastewater organic matter from a biological treatment plant.

Sensors (Basel) 2010 29;10(1):254-65. Epub 2009 Dec 29.

Department of Earth and Environmental Sciences, Sejong University, 98 Gunja-dong, Gwangjin-ku, Seoul, 143-747, Korea.

Spectroscopic and chromatographic changes in dissolved organic matter (DOM) characteristics of influent and treated sewage were investigated for a wastewater treatment plant (WWTP) with a biological advanced process. Refractory DOM (R-DOM) was defined as the dissolved organic carbon concentrations of the samples after 28-day incubation for this study. Specific UV absorbance (SUVA), hydrophobicity, synchronous fluorescence spectra and molecular weight (MW) distributions were selected as DOM characteristics. The percent distribution of R-DOM for the effluent was much higher than that of the influent, indicating that biodegradable DOM was selectively removed during the process. Comparison of the influent versus the effluent sewage revealed that SUVA, fulvic-like fluorescence (FLF), humic-like fluorescence (HLF), the apparent MW values were enhanced during the treatment. This suggests that more aromatic and humic-like compounds were enriched during the biological process. No significant difference in the DOM characteristics was observed between the original effluent (i.e., prior to the incubation) and the influent sewage after the incubation. This result suggests that the major changes in wastewater DOM characteristics occurring during the biological advanced process were similar to those for simple microbial incubation.
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http://dx.doi.org/10.3390/s100100254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3270839PMC
July 2012

Assessment of village health worker training program in Tuguegarao, Philippine.

J Prev Med Public Health 2009 Nov;42(6):377-85

Department of Preventive Medicine, Kosin University College of Medicine, Busan, Korea.

Objectives: This study was performed to evaluate the effectiveness of 'village health worker training program' which aimed to build community participatory health promotion capacity of community leaders in villages of low developed country and to develop methods for further development of the program.

Methods: The intervention group were 134 community leaders from 25 barangays (village). Control group were 149 form 4 barangays. Intervention group participated 3-day training program. Questionnaire was developed based on 'Health Promotion Capacity Checklist' which assessed capacity in 4 feathers; 'knowledge', 'skill', 'commitment', and 'resource'. Each feather was assessed in 4 point rating scale. Capacity scores between intervention group and control group were examined to identify changes between the pre- and post-intervention periods. A qualitative evaluation of the program was conducted to assess the appropriateness of the program. The program was conducted in Tuguegarao city, Philippine in January, 2009.

Results: The result showed significant increases in the total health promotion capacity and each feather of health promotion capacities between pre and post assessment of intervention group. But there was no significant change in that of control group. Participants marked high level of satisfaction for preparedness, selection of main subjects and education method. Qualitative evaluation revealed that training program facilitated community participatory health promotion capacity of participants.

Conclusions: This study suggested that the Village health worker training program is effective for building health promotion capacity of community leaders and it can be a main method for helping low developed countries with further development.
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http://dx.doi.org/10.3961/jpmph.2009.42.6.377DOI Listing
November 2009