Mannitol induces selective astroglial death in the CA1 region of the rat hippocampus following status epilepticus

( Ah Reum Ko ),( Tae Cheon Kang ) 생화학분자생물학회(구 한국생화학분자생물학회) 2015 BMB Reports Vol.48 No.9

In the present study, we addressed the question of whether treatment with mannitol, an osmotic diuretic, affects astrogliovascular responses to status epilepticus (SE). In saline-treated animals, astrocytes exhibited reactive astrogliosis in the CA1-3 regions 2-4 days after SE. In the mannitol-treated animals, a large astroglial empty zone was observed in the CA1 region 2days after SE. This astroglial loss was unrelated to vasogenic edema formation. There was no difference in SE-induced neuronal loss between saline- and mannitol-treated animals. Furthermore, mannitol treatment did not affect astroglial loss and vasogenic edema formation in the dentate gyrus and the piriform cortex. These findings suggest that mannitol treatment induces selective astroglial loss in the CA1 region independent of vasogenic edema formation following SE. These findings support the hypothesis that the susceptibility of astrocytes to SE is most likely due to the distinctive heterogeneity of astrocytes independent of hemodynamics. [BMB Reports 2015; 48(9): 507-512]

The Differential DRP1 Phosphorylation and Mitochondrial Dynamics in the Regional Specific Astroglial Death Induced by Status Epilepticus

Ko, Ah-Reum,Hyun, Hye-Won,Min, Su-Ji,Kim, Ji-Eun Frontiers Media S.A. 2016 Frontiers in cellular neuroscience Vol.10 No.-

<P>The response and susceptibility to astroglial degenerations are relevant to the distinctive properties of astrocytes in a hemodynamic-independent manner following status epilepticus (SE). Since impaired mitochondrial fission plays an important role in mitosis, apoptosis and programmed necrosis, we investigated whether the unique pattern of mitochondrial dynamics is involved in the characteristics of astroglial death induced by SE. In the present study, SE induced astroglial apoptosis in the molecular layer of the dentate gyrus, accompanied by decreased mitochondrial length. In contrast, clasmatodendritic (autophagic) astrocytes in the CA1 region showed mitochondrial elongation induced by SE. Mdivi-1 (an inhibitor of mitochondrial fission) effectively attenuated astroglial apoptosis, but WY14643 (an enhancer of mitochondrial fission) aggravated it. In addition, Mdivi-1 accelerated clasmatodendritic changes in astrocytes. These regional specific mitochondrial dynamics in astrocytes were closely correlated with dynamin-related protein 1 (DRP1; a mitochondrial fission protein) phosphorylation, not optic atrophy 1 (OPA1; a mitochondrial fusion protein) expression. To the best of our knowledge, the present data demonstrate for the first time the novel role of DRP1-mediated mitochondrial fission in astroglial loss. Thus, the present findings suggest that the differential astroglial mitochondrial dynamics may participate in the distinct characteristics of astroglial death induced by SE.</P>

A 70% Ethanol Extract of Mistletoe Rich in Betulin, Betulinic Acid, and Oleanolic Acid Potentiated <i>β</i> -Cell Function and Mass and Enhanced Hepatic Insulin Sensitivity

Ko, Byoung-Seob,Kang, Suna,Moon, Bo Reum,Ryuk, Jin Ah,Park, Sunmin Hindawi Publishing Corporation 2016 Evidence-based Complementary and Alternative Medic Vol.2016 No.-

<P>We investigated that the long-term consumption of the water (KME-W) and 70% ethanol (KME-E) mistletoe extracts had antidiabetic activities in partial pancreatectomized (Px) rats. Px rats were provided with a high-fat diet containing 0.6% KME-E, 0.6% KME-W, and 0.6% dextrin (control) for 8 weeks. As normal-control, Sham-operated rats were provided with 0.6% dextrin. In cell-based studies, the effects of its main terpenoids (betulin, betulinic acid, and oleanolic acid) on glucose metabolism were measured. Both KME-W and KME-E decreased epididymal fat mass by increasing fat oxidation in diabetic rats. KME-E but not KME-W exhibited greater potentiation of first-phase insulin secretion than the Px-control in a hyperglycemic clamp. KME-E also made <I>β</I>-cell mass greater than the control by increasing <I>β</I>-cell proliferation and decreasing its apoptosis. In a euglycemic-hyperinsulinemic clamp, whole-body glucose infusion rate and hepatic glucose output increased with potentiating hepatic insulin signaling in the following order: Px-control, KME-W, KME-E, and normal-control. Betulin potentiated insulin-stimulated glucose uptake via increased PPAR-<I>γ</I> activity and insulin signaling in 3T3-L1 adipocytes, whereas oleanolic acid enhanced glucose-stimulated insulin secretion and cell proliferation in insulinoma cells. In conclusion, KME-E prevented the deterioration of glucose metabolism in diabetic rats more effectively than KME-W and KME-E can be a better therapeutic agent for type 2 diabetes than KME-W.</P>

Two Mutations in pab-1 Encoding Poly(A)-Binding Protein Show Similar Defects in Germline Stem Cell Proliferation but Different Longevity in C. elegans

Ko, Sunny,Park, Jae-Hyung,Lee, Ah-Reum,Kim, Eu-Gene,Kim, Ji-Young,Kawasaki, Ichiro,Shim, Yhong-Hee Korean Society for Molecular and Cellular Biology 2010 Molecules and cells Vol.30 No.2

Four new alleles, bn116, bn117, bn118, and bn119, on LG I were isolated in C. elegans with defects in germline stem cell proliferation. Using genetic mapping and snip-SNP mapping, bn116, bn117, bn118, and bn119 were located 5.0 cM, 1.3 cM, 2.3 cM, and 5.0 cM, respectively, to the right of dpy-5 on LG I. Further, bn116 and bn119 were grouped into the same complementation group by a complementation test. They are loss-of-function recessive alleles that produce homozygous sterile worms whose germ cells do not proliferate during larval development. However, the worms contained normal somatic gonadal structures including distal tip cells and gonadal sheath cells, suggesting that the defect in germline proliferation was not caused by the absence of somatic signaling. Although DAF-16 was localized to the nucleus in all four mutants, the life span was extended only in the three mutants except bn116. These results suggest that the defect in germline stem cell proliferation, the presence of normal somatic gonadal tissues, and DAF-16 nuclear translocation were sufficient for extending the lifespan of the bn117, bn118, and bn119 mutants, but not the bn116 mutant. Intriguingly, bn116 and bn119 were identified as two different mutations on the same gene, pab-1, which encodes a poly(A)-binding protein. Therefore, although the bn116 and bn119 mutations cause similar defects in germ cell proliferation, their effects on life span are different.

대학도서관 디지털 참고정보서비스 가이드라인 개발에 관한 연구

고아름,정은경,Ko, Ah-Reum,Chung, Eun-Kyung 한국과학기술정보연구원 과학기술정보센터 2011 Journal of Information Science Theory and Practice Vol.42 No.2

Digital reference services have been a key role in academic libraries in the context of various digital environments. The guidelines for the digital reference service are one of important aspects to improve the quality of services and system design and implement better services. In this study, by case studies and a questionnaire survey for academic librarians, the guideline for the digital reference service is suggested with three phases; plan, operation and evaluation. The guideline for the digital reference services suggested in this study is expected to support digital reference services in academic library environment. 대학도서관의 참고정보서비스는 정보통신기술과 인터넷의 발전으로 온라인상에서 이용자와 사서의 질문답변과정이 가능한 디지털 참고정보서비스로 발전되어 왔다. 이에 본 연구는 이러한 디지털 환경에서 국내 대학도서관의 디지털 참고정보서비스가 효율적이며 체계적으로 운영될 수 있도록 필요한 조건 중 가장 근본이 되는 가이드라인을 제시하였다. 디지털 참고정보서비스 가이드라인은 계획, 운영, 평가 단계로 구분된다. 계획 단계는 운영/관리, 협력, 서비스정책, 디자인의 4개 범주로 구성되어 있으며, 운영 단계는 질문/답변, 정보원, 근무시간, 홍보, 교육과 같은 5개 범주로 구성되어 있다. 마지막으로 평가 단계는 서비스평가와 평가방법으로 2개의 범주로 구성되어 있다.

P2X7 receptor-mediated PARP1 activity regulates astroglial death in the rat hippocampus following status epilepticus

Kim, Ji Yang,Ko, Ah-Reum,Kim, Ji-Eun Frontiers Media S.A. 2015 Frontiers in cellular neuroscience Vol.9 No.-

<P>Poly(ADP-ribose) polymerase-1 (PARP1) plays a regulatory role in apoptosis, necrosis, and other cellular processes after injury. Recently, we revealed that PARP1 regulates the differential neuronal/astroglial responses to pilocarpine-induced status epilepticus (SE) in the distinct brain regions. In addition, P2X7 receptor (P2X7R), an ATP-gated ion channel, activation accelerates astroglial apoptosis, while it attenuates clasmatodendrosis (lysosome-derived autophagic astroglial death). Therefore, we investigated whether P2X7R regulates regional specific astroglial PARP1 expression/activation in response to SE. In the present study, P2X7R activation exacerbates SE-induced astroglial apoptosis, while P2X7R inhibition attenuates it accompanied by increasing PARP1 activity in the molecular layer of the dentate gyrus following SE. In the CA1 region, however, P2X7R inhibition deteriorates SE-induced clasmatodendrosis via PARP1 activation following SE. Taken together, our findings suggest that P2X7R function may affect SE-induced astroglial death by regulating PARP1 activation/expression in regional-specific manner. Therefore, the selective modulation of P2X7R-mediated PARP1 functions may be a considerable strategy for controls in various types of cell deaths.</P>

Characterization and hydrogen generation of Zn-containing fullerene

Won Chun Oh,Ah- Reum Jung,Weon-Bae Ko 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.3

In this study, the structural variations, surface states and mass transformation of fullerene [C60] derivatives are investigated through the preparation of an oxidized fullerene [C60O] and a Zn-containing fullerene compared to pristine fullerene [C60]. These were synthesized by an improved oxidation method using 3-chloroperbenzoic acid. From the XRD data, weak peaks of metallic zinc with pristine fullerene [C60] peaks were observed in the X-ray diffraction patterns for the Zn-containing fullerene. SEM micrographs for the metallic Zn-containing fullerene indicated that practically all the zinc introduced was located onto the carbon cages and consequently, it was dispersed into very small crystallites with growth of zinc metals. From the MALDITOF mass spectra, the differences in the spectra recorded on two types of fullerenes are due to the oxidation including chemical bonding and interposing of metallic zinc in the fullerene [C60] molecules. The FT-IR spectra gave additional information on the functional components on the surfaces of the Zn-containing fullerene. The EDX spectrum of Zn-containing fullerene showed the presence of C and O with strong Zn peaks. From the H2 gas generation result, it is considered that a KOH concentration in the Zn-containing fullerene is a helpful factor in the hydrogen generation performance. A satisfactory hydrogen generation performance was achieved on a Zn-containing fullerene treated with an increase of KOH the concentration. In this study, the structural variations, surface states and mass transformation of fullerene [C60] derivatives are investigated through the preparation of an oxidized fullerene [C60O] and a Zn-containing fullerene compared to pristine fullerene [C60]. These were synthesized by an improved oxidation method using 3-chloroperbenzoic acid. From the XRD data, weak peaks of metallic zinc with pristine fullerene [C60] peaks were observed in the X-ray diffraction patterns for the Zn-containing fullerene. SEM micrographs for the metallic Zn-containing fullerene indicated that practically all the zinc introduced was located onto the carbon cages and consequently, it was dispersed into very small crystallites with growth of zinc metals. From the MALDITOF mass spectra, the differences in the spectra recorded on two types of fullerenes are due to the oxidation including chemical bonding and interposing of metallic zinc in the fullerene [C60] molecules. The FT-IR spectra gave additional information on the functional components on the surfaces of the Zn-containing fullerene. The EDX spectrum of Zn-containing fullerene showed the presence of C and O with strong Zn peaks. From the H2 gas generation result, it is considered that a KOH concentration in the Zn-containing fullerene is a helpful factor in the hydrogen generation performance. A satisfactory hydrogen generation performance was achieved on a Zn-containing fullerene treated with an increase of KOH the concentration.

Risk Assessment Program of Highly Pathogenic Avian Influenza with Deep Learning Algorithm

Yoon Hachung,Jang Ah-Reum,Jung Chungsik,Ko Hunseok,Lee Kwang-Nyeong,Lee Eunesub 질병관리본부 2020 Osong Public Health and Research Persptectives Vol.11 No.4

Objectives This study presents the development and validation of a risk assessment program of highly pathogenic avian influenza (HPAI). This program was developed by the Korean government (Animal and Plant Quarantine Agency) and a private corporation (Korea Telecom, KT), using a national database (Korean animal health integrated system, KAHIS). Methods Our risk assessment program was developed using the multilayer perceptron method using R Language. HPAI outbreaks on 544 poultry farms (307 with H5N6, and 237 with H5N8) that had available visit records of livestock-related vehicles amongst the 812 HPAI outbreaks that were confirmed between January 2014 and June 2017 were involved in this study. Results After 140,000 iterations without drop-out, a model with 3 hidden layers and 10 nodes per layer, were selected. The activation function of the model was hyperbolic tangent. Precision and recall of the test gave F1 measures of 0.41, 0.68 and 0.51, respectively, at validation. The predicted risk values were higher for the “outbreak” (average ± SD, 0.20 ± 0.31) than “non-outbreak” (0.18 ± 0.30) farms (p < 0.001). Conclusion The risk assessment model developed was employed during the epidemics of 2016/2017 (pilot version) and 2017/2018 (complementary version). This risk assessment model enhanced risk management activities by enabling preemptive control measures to prevent the spread of diseases.

Preparation and characterization of fullerene dimer [C₁₂₀] by trichloroperbenzoic acid oxidation method

Oh, Won-Chun,Jung, Ah-Reum,Ko, Weon-Bae The Korean Society of Analytical Sciences 2007 분석과학 Vol.20 No.2

In this study, we present the preparation and characterization of oxidized fullerene and fullerene dimer [$C_{120}$]. From the XRD data, other weak peaks with pristine fullerene [$C_{60}$] peaks were observed in the X-ray diffraction patterns for fullerene dimer [$C_{120}$]. SEM micrographs for the fullerene dimer [$C_{120}$] indicated that practically all the surface state was shown the drastic morphology changes and its outer surface is clearly visible and resulted in clogging and frost-like formation. From the MALDI-TOF mass spectra, the differences in the spectra recorded on two kinds of fullerene are due to the oxidation including chemical bonding and bridging between the $C_{60}$ molecules. We also obtained additional information from FT-IR spectra on functional component on the chemically modified surface of oxidized fullerene and fullerene dimer [$C_{120}$].

Mitochondrial Translocation of High Mobility Group Box 1 Facilitates LIM Kinase 2-Mediated Programmed Necrotic Neuronal Death

Hyun, Hye-Won,Ko, Ah-Reum,Kang, Tae-Cheon Frontiers Media S.A. 2016 Frontiers in cellular neuroscience Vol.10 No.-

<P>High mobility group box 1 (HMGB1) acts a signaling molecule regulating a wide range of inflammatory responses in extracellular space. HMGB1 also stabilizes nucleosomal structure and facilitates gene transcription. Under pathophysiological conditions, nuclear HMGB1 is immediately transported to the cytoplasm through chromosome region maintenance 1 (CRM1). Recently, we have reported that up-regulation of LIM kinase 2 (LIMK2) expression induces HMGB1 export from neuronal nuclei during status epilepticus (SE)-induced programmed neuronal necrosis in the rat hippocampus. Thus, we investigated whether HMGB1 involves LIMK2-mediated programmed neuronal necrosis, but such role is not reported. In the present study, SE was induced by pilocarpine in rats that were intracerebroventricularly infused with saline, control siRNA, LIMK2 siRNA or leptomycin B (LMB, a CRM1 inhibitor) prior to SE induction. Thereafter, we performed Fluoro-Jade B staining, western blots and immunohistochemical studies. LIMK2 knockdown effectively attenuated SE-induced neuronal death and HMGB1 import into mitochondria accompanied by inhibiting nuclear HMGB1 release and abnormal mitochondrial elongation. LMB alleviated SE-induced neuronal death and nuclear HMGB1 release. However, LMB did not prevent mitochondrial elongation induced by SE, but inhibited the HMGB1 import into mitochondria. The efficacy of LMB was less effective to attenuate SE-induced neuronal death than that of LIMK2 siRNA. These findings indicate that nuclear HMGB1 release and the subsequent mitochondrial import may facilitate and deteriorate programmed necrotic neuronal deaths. The present data suggest that the nuclear HMGB1 release via CRM1 may be a potential therapeutic target for the programmed necrotic neuronal death induced by SE.</P>