진행성 치매와 반복되는 뇌졸중을 보인 뇌 아밀로이드 혈관병증 1예

유봉구,곽강호,김태유,김광수,유경무 대한치매학회 2004 Dementia and Neurocognitive Disorders Vol.3 No.1

Cerebral amyloid angiopathy can cause intracerebral hemorrhage, progressive dementia, seizure and transient ischemic attacks. Dementia is a relatively common manifestation and associated with the presence of recurrent strokes and leukoencephalopathy. A 66-year-old right-handed man with hypertension and recurrent strokes presented with rapidly progressive dementia and sudden onset of dysarthria and dizziness. He showed memory impairment, personality and behavioral changes, and executive dysfunction for one and an half years. These symptoms developed insidiously and quite rapidly without fluctuation. Brain CT showed a small hemorrhage in the right cerebellum. Brain MRI, especially gradient-echo images revealed multiple cortical and cortico-subcortical microbleeds. Four weeks later, right hemiparesis suddenly developed and a repeated MRI showed a new left corona radiata infarction. We learn from this case that gradient-echo MR images should be performed in patients with rapidly progressive dementia and recurrent strokes.

Effects of Acute Exercise on Mitochondrial Function, Dynamics, and Mitophagy in Rat Cardiac and Skeletal Muscles

Yoo, Su-Zi,No, Mi-Hyun,Heo, Jun-Won,Park, Dong-Ho,Kang, Ju-Hee,Kim, Joon-Hee,Seo, Dae-Yun,Han, Jin,Jung, Su-Jeen,Kwak, Hyo-Bum Korean Continence Society 2019 International Neurourology Journal Vol.23 No.S1

<P><B>Purpose</B></P><P>This study aimed to investigate the effects of single-bout exercise on mitochondrial function, dynamics (fusion, fission), and mitophagy in cardiac and skeletal muscles.</P><P><B>Methods</B></P><P>Fischer 344 rats (4 months old) were randomly divided into the control (CON) or acute exercise (EX) group (n=10 each). The rats performed a single bout of treadmill exercise for 60 minutes. Mitochondrial function (e.g., O<SUB>2</SUB> respiration, H<SUB>2</SUB>O<SUB>2</SUB> emission, Ca<SUP>2+</SUP> retention capacity), mitochondrial fusion (e.g., Mfn1, Mfn2, Opa1), mitochondrial fission (e.g., Drp1, Fis1), and mitophagy (e.g., Parkin, Pink1, LC3II, Bnip3) were measured in permeabilized cardiac (e.g., left ventricle) and skeletal (e.g., soleus, white gastrocnemius) muscles.</P><P><B>Results</B></P><P>Mitochondrial O<SUB>2</SUB> respiration and Ca<SUP>2+</SUP> retention capacity were significantly increased in all tissues of the EX group compared with the CON group. Mitochondrial H<SUB>2</SUB>O<SUB>2</SUB> emissions showed tissue-specific results; the emissions showed no significant differences in the left ventricle or soleus (type I fibers) but was significantly increased in the white gastrocnemius (type II fibers) after acute exercise. Mitochondrial fusion and fission were not altered in any tissues of the EX group. Mitophagy showed tissue-specific differences: It was not changed in the left ventricle or white gastrocnemius, whereas Parkin and LC3II were significantly elevated in the soleus muscle.</P><P><B>Conclusions</B></P><P>A single bout of aerobic exercise may improve mitochondrial function (e.g., O<SUB>2</SUB> respiration and Ca<SUP>2+</SUP> retention capacity) in the heart and skeletal muscles without changes in mitochondrial dynamics or mitophagy.</P>

Nitrogen-rich 1T′-MoS₂ layered nanostructures using alkyl amines for high catalytic performance toward hydrogen evolution

Kwak, In Hye,Kwon, Ik Seon,Abbas, Hafiz Ghulam,Jung, Gabin,Lee, Yeron,Debela, Tekalign Terfa,Yoo, Seung Jo,Kim, Jin-Gyu,Park, Jeunghee,Kang, Hong Seok The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.30

<P>The imminent global energy crisis and current environmental issues have stimulated considerable research on high-performance catalysts for sustainable hydrogen energy generation. Two-dimensional layered MoS2 has recently drawn worldwide attention because of its excellent catalytic properties for the hydrogen evolution reaction (HER). In the present work, we prepared nitrogen (N)-rich 1T′ (distorted 1T) phase MoS2 layered nanostructures using different alkyl amines with 1-4 nitrogen atoms (methylamine, ethylenediamine, diethylenetriamine, and triethylenetetramine) as intercalants. The amine molecules intercalate at 10 atomic%, and simultaneously supply the N atoms that substitute the S atoms to produce the N-doped MoS2, whose composition is MoS2(1−x)Nx, where <I>x</I> = 0.1-0.26. MoS2 prepared with amines having more N atoms has enhanced catalytic HER performance: a Tafel slope of 36 mV dec<SUP>−1</SUP> and 10 mA cm<SUP>−2</SUP> at −160 mV (<I>vs.</I> RHE). First-principles calculations showed that the amine intercalation and N doping increase the density of states near the Fermi level in a narrow range and bring about an effective overlap of the dz2(Mo), pz(S), and pz(N) states. These factors in turn increase the carrier (electron) concentration and mobility for improved HER. The calculation also predicted that the most active site is S vacancies. The present work illustrates how the HER catalytic performance of 1T′ phase MoS2 can be effectively controlled by the amine molecules.</P>

Definitive concurrent chemoradiotherapy in locally advanced pancreatic cancer

Kwak, Yoo-Kang,Lee, Jong Hoon,Lee, Myung-Ah,Chun, Hoo-Geun,Kim, Dong-Goo,You, Young Kyoung,Hong, Tae-Ho,Jang, Hong Seok The Korean Society for Radiation Oncology 2014 Radiation Oncology Journal Vol.32 No.2

Purpose: Survival outcome of locally advanced pancreatic cancer has been poor and little is known about prognostic factors of the disease, especially in locally advanced cases treated with concurrent chemoradiation. This study was to analyze overall survival and prognostic factors of patients treated with concurrent chemoradiotherapy (CCRT) in locally advanced pancreatic cancer. Materials and Methods: Medical records of 34 patients diagnosed with unresectable pancreatic cancer and treated with definitive CCRT, from December 2003 to December 2012, were reviewed. Median prescribed radiation dose was 50.4 Gy (range, 41.4 to 55.8 Gy), once daily, five times per week, 1.8 to 3 Gy per fraction. Results: With a mean follow-up of 10 months (range, 0 to 49 months), median overall survival was 9 months. The 1- and 2-year survival rates were 40% and 10%, respectively. Median and mean time to progression were 5 and 7 months, respectively. Prognostic parameters related to overall survival were post-CCRT CA19-9 (p = 0.02), the Eastern Cooperative Oncology Group (ECOG) status (p < 0.01), and radiation dose (p = 0.04) according to univariate analysis. In multivariate analysis, post-CCRT CA19-9 value below 180 U/mL and ECOG status 0 or 1 were statistically significant independent prognostic factors associated with improved overall survival (p < 0.01 and p = 0.02, respectively). Conclusion: Overall treatment results in locally advanced pancreatic cancer are relatively poor and few improvements have been accomplished in the past decades. Post-treatment CA19-9 below 180 U/mL and ECOG performance status 0 and 1 were significantly associated with an improved overall survival.

Local kallikrein–kinin system is involved in podocyte apoptosis under diabetic conditions

Kwak, Seung-Jae,Paeng, Jisun,Kim, Do Hee,Lee, Sun Ha,Nam, Bo-Young,Kang, Hye Young,Li, Jin Ji,Jung, Dong-Sub,Han, Seung Hyeok,Ryu, Dong-Ryeol,Park, Jung Tak,Chang, Tae Ik,Yoo, Tae-Hyun,Han, Dae Suk,Ka Springer-Verlag 2011 Apoptosis Vol.16 No.5

Two-dimensional MoS2-melamine hybrid nanostructures for enhanced catalytic hydrogen evolution reaction

Kwak, In Hye,Kwon, Ik Seon,Debela, Tekalign Terfa,Seo, Jaemin,Ahn, Jae-Pyoung,Yoo, Seung Jo,Kim, Jin-Gyu,Park, Jeunghee,Kang, Hong Seok The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.39

<P>Two-dimensional (2D) MoS2 nanostructures have attracted much attention in recent years because of their excellent electrocatalytic activity toward the hydrogen evolution reaction (HER). Herein, we report unique 2D hybrid nanostructures of MoS2 and melamine synthesized <I>via</I> a one-step solvothermal process. Remarkably, few-layer metallic 1T′ phase MoS2 nanoflakes and orthorhombic phase melamine aggregate to form nanoplates. At a controlled concentration, the melamine molecules intercalated into the 1T′ phase MoS2 by forming charge-transfer complexes. The hybrid complexes with 7% intercalated melamine exhibited excellent performance for the catalytic HER, with a current of 10 mA cm<SUP>−2</SUP> at 0.136 V (<I>vs.</I> RHE) and a Tafel slope of 37 mV dec<SUP>−1</SUP>. First-principles calculations showed that the intercalation of hydrogen-bonded melamine clusters could stabilize the 1T′ phase MoS2<I>via</I> substantial charge transfer. The activation barrier was calculated for the Volmer-Heyrovsky reactions, by identifying the active sites of the Volmer reaction as the basal S atoms above the hydrogen-bonded amine group of melamine. This rationalizes the dependence of the catalytic activity on the concentration of intercalated melamine. The present study highlights the opportunities for producing unique 2D hybrid complexes to enhance the HER catalytic activity by controlling the intercalating organic molecules.</P>

Activation of the renin–angiotensin system within podocytes in diabetes

Yoo, T-H,Li, J-J,Kim, J-J,Jung, D-S,Kwak, S-J,Ryu, D-R,Choi, H Y,Kim, J S,Kim, H J,Han, S H,Lee, J E,Han, D S,Kang, S-W International Society of Nephrology 2007 Kidney international Vol.71 No.10

The autocrine and paracrine activation of the renin–angiotensin system (RAS) within cells of the kidney plays a role in the overall pathophysiology of the renal disease due to diabetes. In this study, we focus on components of the RAS in the podocyte as these cells are important in the pathogenesis of glomerulosclerosis and proteinuria. Immortalized mouse podocytes were exposed to media containing normal glucose (NG) or high glucose (HG) for in vitro studies. In vivo studies utilized kidney tissue obtained from rats treated for 3 months with streptozotocin to induce diabetes. Angiotensinogen (AGT) and the angiotensin II (AII) type 1 receptor mRNA and protein were significantly increased in the podocytes cultured under the high glucose conditions. Both angiotensins I and II levels were significantly higher in cell lysates and the conditioned media of cells grown in high glucose. There were no differences in renin activity, angiotensin-converting enzyme level, or AII type 2 receptor level. Glomerular AGT and AII type 1 receptor assessed by means of immunohistochemistry were increased in diabetic rats compared with the control rats. Other measured components of the RAS within the glomeruli were not different. We suggest that increased AGT, an attendant increase in AII and increased AII type 1 receptor in podocytes experiencing diabetic conditions play an important role in the pathogenesis of diabetic nephropathy.Kidney International (2007) 71, 1019–1027. doi:10.1038/sj.ki.5002195; published online 14 March 2007

Overexpression of goosecoid homeobox is associated with chemoresistance and poor prognosis in ovarian carcinoma

KANG, KYONG-WON,LEE, MI-JUNG,SONG, JI-AE,JEONG, JU-YEON,KIM, YOO-KYONG,LEE, CHAN,KIM, TAE-HEON,KWAK, KYU-BEOM,KIM, OK-JUN,AN, HEE JUNG Spandidos Publications 2014 ONCOLOGY REPORTS Vol.32 No.1

<P>Ovarian carcinoma is the most lethal cancer among all gynecological malignancies due to recurrence through chemoresistance. The aim of the present study was to identify new biomarkers to predict chemoresistance and prognosis in ovarian carcinomas. The mRNA expression by qRT-PCR was examined in 60 ovarian serous carcinomas for selected genes from the screening by PCR array focusing on apoptosis, epithelial-to-mesenchymal transition and cancer pathways. The clinical impact was assessed by analyzing the correlation between gene expression and clinicopathological variables. Further validation with immunohistochemistry was performed with 75 cases of serous carcinomas. The chemoresistance was significantly associated with high expression of FOS, GSC, SNAI1, TERT and TNFRSF10D, and low expression of CDKN1A, TNFRSF10A, TNFRSF10C and TRAF1 (p<0.05, t-test). Low expression of TRAF1 and high expression of E2F1, FOS, TERT and GSC were significantly associated with advanced clinical stage (p<0.05, χ2-test). Lymph node metastasis was significantly associated with high expression of GSC. The upregulation group of TERT, GSC, NOTCH1 and SNAI1, and downregulation group of TRAF1 were significantly associated with poor overall survival (p<0.05, log-rank test). On further validation with immunohistochemistry, overexpression of goosecoid homeobox (GSC) was associated with poor overall survival. The results suggest that GSC is the most potential biomarker of drug response and poor prognosis in ovarian serous carcinomas.</P>

Crucial role of a nickel substrate in Co₃O₄ pseudocapacitor directly grown on nickel and its electrochemical properties

Yoo, C.Y.,Park, J.,Yun, D.S.,Yu, J.H.,Yoon, H.,Kim, J.N.,Yoon, H.C.,Kwak, M.,Kang, Y.C. Elsevier Sequoia 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.676 No.-

In this study, Co<SUB>3</SUB>O<SUB>4</SUB> directly grown on a porous nickel substrate was successfully prepared and characterised as a potential candidate for pseudocapacitor applications. The electrochemical properties of Co<SUB>3</SUB>O<SUB>4</SUB> were adversely affected by the sluggish charge transfer at the interface between the electrode and electrolyte and the diffusion of ions from the electrolyte to the interface. These challenges were overcome by the introduction of a high-surface-area Ni substrate for Co<SUB>3</SUB>O<SUB>4</SUB>, which improves the electrochemical performance of Co<SUB>3</SUB>O<SUB>4</SUB>; this is indicated by the excellent capacitance and low impedance. This study suggests that the electrochemical properties of several pseudocapacitive oxide materials can be tailored by increasing the surface area of the metal substrate.

Thalamo-cortical system involving higher-order nuclei in patients with first-episode psychosis

( Kang Ik K. Cho ),( Yoo Bin Kwak ),( Wu Jeong Hwang ),( Junhee Lee ),( Minah Kim ),( Tae Young Lee ),( Jun Soo Kwon ) 생화학분자생물학회(구 한국생화학분자생물학회) 2018 BMB Reports Vol.51 No.9

Based on the piling reports of disruptions in the thalamus of patients with schizophrenia, the alteration in the thalamo-cortical system has been regarded as the core pathophysiology. As the thalamus is composed of distinctive nuclei with different cytoarchitecture and cortical connections, nuclei specific investigations have been actively conducted in post-mortem studies. In addition, the importance of early changes has been highlighted, which in turn has led to investigations of the thalamo-cortical system using non-invasive neuroimaging methods. From this perspective, the early structural changes in the thalamo-cortical system, such as the thalamo-cortical connection and nuclei specific microstructural changes (which are coherent with findings from post-mortem methods) will be briefly discussed. The main findings, which are the reduced thalamo-prefrontal connection and reduced microstructural complexity in the higher-order nuclei detected in first-episode psychosis patients, suggest the occurrence of early alterations within and between the communication hub of the brain and cortex. These findings suggest not only directions for further studies for unveiling the thalamo-cortical system related pathophysiology, but also the possibility of using the reduced microstructural complexity in the higher order nucleus as a biomarker for schizophrenia. [BMB Reports: Perspective 2018; 51(9): 427-428]