좌상후 말초신경의 조직학적 변화

정소학,김성대,권영호,손정환,백선용 고신대학교 의학부 2000 高神大學校 醫學部 論文集 Vol.15 No.1

Background The morphological changes in the peripheral nerve and S-100 immunoreactivity were studied after axotomy. Methods Adult Sprague-Dawley rats received crush injury with aneurysmal clip in the sciatic nerve at mid-thigh level. The animals were cardiac perfused with 4% paraformaldehyde for cryostat section and half Karnovsky fixative for semithin section from 6 hours to 4 weeks after crush injury. The immunohistochemistry of Schwan cells was performed. Results Degeneration of myelin sheath and endoneurial edema were observed at 6 hours. Macrophages were invaded into the basal lamina tube and phagocytosed the destructed axons and myelin sheath at 3 days. Proliferation of Schwann cells in the basal lamina tube was observed at 5 days group. Thin myelinated nerve fiber and degeneration of myelin sheath were observed at 2 weeks. Conclusion These results indicate that after crush injury of the peripheral nerve regeneration of myelin sheath and Schwan cells is partially completed in 1 week.

두경부 악성종양 절제술 후 유리피판을 이용한 재건술 40예의 고찰

백정환,손영익,김성민,추광철,하범준,심영목 대한이비인후과학회 1999 대한이비인후과학회지 두경부외과학 Vol.42 No.7

Role of salivary function in patients with globus pharyngeus

Baek, Chung-Hwan,Chung, Man Ki,Choi, Joon Young,So, Yoon Kyoung,Son, Young-Ik,Jeong, Han-Sin Wiley Subscription Services, Inc., A Wiley Company 2010 Head & neck Vol.32 No.2

<B>Background.</B><P>Our aim was to investigate the prevalence and the clinical role of salivary hypofunction in patients with globus sensation.</P><B>Methods.</B><P>We conducted a prospective observational study in 340 patients with globus pharyngeus. A standard questionnaire and <SUP>99m</SUP>Tc-pertechnate salivary scintigraphy were used to evaluate salivary hypofunction, with a full examination from the nasal cavity to the larynx (N = 303). We also investigated the effect of xerostomia management on globus symptoms (N = 252).</P><B>Results.</B><P>The symptom scores for xerostomia were higher in patients with severe globus (p < .05). Objective salivary hypofunction was noted in 57.4% of the patients, based on the reference values from control groups. Globus symptoms were more severe in the subgroup with salivary hypofunction (p = .0447). Conservative management of xerostomia significantly reduced the severity of globus at 1 and 3 months (p = .0002) regardless of salivary function.</P><B>Conclusions.</B><P>Salivary hypofunction seems to be an aggravating factor in globus pharyngeus, but not a direct cause. Conservative management of xerostomia improves globus symptoms. © 2009 Wiley Periodicals, Inc. Head Neck, 2010</P>

Synthesis of SnS Thin Films by Atomic Layer Deposition at Low Temperatures

Baek, In-Hwan,Pyeon, Jung Joon,Song, Young Geun,Chung, Taek-Mo,Kim, Hae-Ryoung,Baek, Seung-Hyub,Kim, Jin-Sang,Kang, Chong-Yun,Choi, Ji-Won,Hwang, Cheol Seong,Han, Jeong Hwan,Kim, Seong Keun American Chemical Society 2017 Chemistry of materials Vol.29 No.19

<P>Two-dimensional (2-D) metal chalcogenides have received great attention because of their unique properties, which are different from bulk materials. A challenge in implementing 2-D metal chalcogenides in emerging devices is to prepare a well-crystallized layer over large areas at temperatures compatible with current fabrication processes. Tin monosulfide, a <I>p</I>-type layered semiconductor with a high hole mobility, is a promising candidate for realizing large-area growth at low temperatures because of its low melting point. However, tin sulfides exist in two notable crystalline phases, SnS and SnS<SUB>2</SUB>. Therefore, it is imperative to control the oxidation state of Sn to achieve a pure SnS film. Here, the synthesis of SnS thin films by atomic-layer-deposition (ALD) is demonstrated using bis(1-dimethylamino-2-methyl-2-propoxy)tin(II) and H<SUB>2</SUB>S as Sn and S sources, respectively, over a wide temperature window (90–240 °C). Impurities such as carbon, oxygen, and nitrogen were negligibly detected. The morphological evolution of plate-like orthorhombic SnS grains was observed above 210 °C. Moreover, properties of thin film transistors and gas sensors using SnS films as the active layers were investigated. The SnS ALD process would provide promising opportunities to exploit the intriguing properties of the 2-D metal chalcogenides for realizing emerging electronic devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2017/cmatex.2017.29.issue-19/acs.chemmater.7b01856/production/images/medium/cm-2017-018563_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm7b01856'>ACS Electronic Supporting Info</A></P>

Characteristics of Tissue-Engineered Cartilage on Macroporous Biodegradable PLGA Scaffold

Baek, Chung-Hwan,Ko, Ye-Jeung The American Laryngological, Rhinological Otologic 2006 The Laryngoscope Vol.116 No.10

BACKGROUND:: The purpose of this study was to establish in vivo culture of chondrocytes on biodegradable, poly-D,L-lactic-co-glycolic acid (PLGA) scaffolds and to analyze the characteristics of the reconstructed cartilage. METHODS:: In vitro cultured chondrocytes that were grown on a polyhydroxyethyl methacrylate (poly-HEMA) coated dish were seeded onto the PLGA scaffolds to make a cell–polymer construct before implantation. One cell scaffold construct was carefully implanted in the subcutaneous pocket of a nude mouse and another cell-free scaffold was implanted in the opposite side of the same nude mouse as the control. Morphologic, biochemical, and immunohistochemical characteristics of cells cultured within the PLGA constructs were examined after 8 weeks and 16 weeks of harvesting in the nude mouse. RESULTS:: New cartilage began to be generated in the period of 8 weeks and the neocartilage formation was accomplished in 4 months with the exact dimensions of the original scaffold in this in vivo study. All the explants showed the irregular shape of viable chondrocytes within normal lacunae and a mature cartilaginous matrix, and they positively immunostained for collagen type II. CONCLUSION:: The new tissue-engineered cartilage in vivo on PLGA scaffolds displayed the biochemical characteristics of cartilage tissue, and it showed chondrocyte-specific phenotypes and morphology that were similar to the native cartilage.

피판 부전증의 구제를 위한 약용거머리 치료법

백정환(Chung Hwan Baek),신준호(Juno Shin),박주현(Joo Hyun Park) 대한두경부종양학회 2000 대한두경부 종양학회지 Vol.16 No.1

The medicinal leech, Hirudo medicinalis, has been used for salvage of the venous-congested flap following reconstructive surgery, with increasing frequency during the last two decades. Medicinal leech therapy is a safe, efficacious, economical, and well-tolerated intervention. The flap salvage with leeching occurs in approximately 70% of cases, and leeches need to be used as early as possible. At the time of the bite, evacuation of blood and injection of the leech saliva products, including anticoagulants and inhibitors of platelet aggregation, maintain capillary circulation of the flap, and then venous capillary return is established across the wound by angiogenesis. One of the salivary products, hirudin, represents the first parenteral anticoagulant introduced since the discovery of heparin. We analyzed two cases in which flap salvage with leeching was attempted, and reviewed medicinal leech therapy on the basis of our experiences and literature review. This has not been documented in the head and neck surgery literature in our country.

활강 압박고 나사와 전자부 고정 금속판을 이용한 대퇴골 전자부 분쇄골절의 치료

백승기,최영준,김정환,안형선,황재광,김유진,안현태,박경준,조재우 대한골절학회 2002 대한골절학회지 Vol.15 No.2

목적 : 대퇴골 전자부 분쇄 골절기 활강 압박고 나사만으로 치료한 결과와 활강 압박고 나사와 전자부 고정화 금속판을 함께 사용하여 치료한 결과를 비교 관찰하고자 하였다. 연구 대상 및 방법 : 1997년 6월부터 2000년 8월까지 대퇴골 전자부 골절로 입원하였던 환자로 전자 관통 골절(A2)과 대 전자부 하외측 피질골에 골절선이 동반된 전자간 골절(A3) 환자 중 대전자부 골절이 동반된 환자로 32명을 대상으로 하였으며 활강 압박고 나사만 사용한 활강 압박고 나사군 과 전자부 고정화 금속판을 같이 사용한 전자부 고정화 금속판군을 나누어서 단순 방사선 사진상 지연나사의 활강 정도와 대전자의 외측 전위 정도 및 골유합 기간을 추시하였다. 결과 : 모든 예에서 골유합이 되었으며 추시 단순 방사선 사진상으로 골유합이 되었을 때 측정한 지연 나사 활강 정도는 활강 압박고 나사군에서는 14.5mm, 전자부 고정화 금속판 군에서는 12.6mm이었다. 대퇴 대전자 평균 외측 전위 정도는 활강 압박고 나사군에서는 9.8mm, 전자부 고정화 금속판군에서는 1.2mm이었다. 결론 : 활강 압박고 나사와 전자부 고정화 금속판을 이용하여 대퇴골 전자간 분쇄 골절과 함께 대전자부 골절이 동반되어있는 경우의 치료시 방사선학적 추시상 지연나사의 활강 정도 및 대전자 외측 전위가 적었으며, 기존의 압박고 나사를 단독으로 사용하는 것에 비하여 수술시 얻은 골절 정복 및 내고정의 위치를 계속 유지하여 골유합을 시킬 수 있는 좋은 방법이라 사료된다. Purpose : The purpose of this study is to evaluate the results of treatment of comminuted femoral trochanteric fracture using dynamic hip screw(DHS) with trochanteric stabilizing plate(TSP) and DHS only. Materials and Methods : we analysed retrospectively 32 cases that has fracture extends over two or more levels of medial cortex(A2 of AO classification) and fracture extends through lateral cortex of femur(A3 of AO classicification) of femoral trochanteric fractures between 1997 and 2000. On simple AP radiograph of the DHS with TSP(n=16) and DHS only group(n=16), we reviewed bony union, slippage of lag screw, lateral displacement of greater trochanter. Result : Bony union was observed in all cases. When bony union is done in follow up radiograph, Mean slippage of lag screw is 14.5mm in DHS only group, 12.6㎜ in DHS with TSP group and mean lateral displacement of greater trochanter is 9.8㎜ in DHS only group, 1.2mm in DHS with TSP group. Conclusion : Use of DHS with TSP in comminuted femoral trochanteric fracture is lesser slippage of lag screw and lateral displacement of greater trochanter than DHS only used, and that is better method to maintain fracture reduction and internal fixation in treatment of comminuted femoral trochanteric fractures than DHS only.

Diagnostic Performance of the Modified Korean Thyroid Imaging Reporting and Data System for Thyroid Malignancy: A Multicenter Validation Study

Chung Sae Rom,Ahn Hye Shin,Choi Young Jun,Lee Ji Ye,Yoo Roh-Eul,Lee Yoo Jin,Kim Jee Young,Sung Jin Yong,김지훈,Baek Jung Hwan 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.9

Objective: To evaluate the diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System (K-TIRADS), and compare it with the 2016 version of K-TIRADS using the Thyroid Imaging Network of Korea. Materials and Methods: Between June and September 2015, 5708 thyroid nodules (≥ 1.0 cm) from 5081 consecutive patients who had undergone thyroid ultrasonography at 26 institutions were retrospectively evaluated. We used a biopsy size threshold of 2 cm for K-TIRADS 3 and 1 cm for K-TIRADS 4 (modified K-TIRADS 1) or 1.5 cm for K-TIRADS 4 (modified K-TIRADS 3). The modified K-TIRADS 2 subcategorized the K-TIRADS 4 into 4A and 4B, and the cutoff sizes for the biopsies were defined as 1 cm for K-TIRADS 4B and 1.5 cm for K-TIRADS 4A. The diagnostic performance and the rate of unnecessary biopsies of the modified K-TIRADS for detecting malignancy were compared with those of the 2016 K-TIRAD, which were stratified by nodule size (with a threshold of 2 cm). Results: A total of 1111 malignant nodules and 4597 benign nodules were included. The sensitivity, specificity, and unnecessary biopsy rate of the benign nodules were 94.9%, 24.4%, and 60.9% for the 2016 K-TIRADS; 91.0%, 39.7%, and 48.6% for the modified K-TIRADS 1; 84.9%, 45.9%, and 43.5% for the modified K-TIRADS 2; and 76.1%, 50.2%, and 40.1% for the modified K-TIRADS 3. For small nodules (1–2 cm), the diagnostic sensitivity of the modified K-TIRADS decreased by 5.2–25.6% and the rate of unnecessary biopsies reduced by 19.2–32.8% compared with those of the 2016 K-TIRADS (p < 0.001). For large nodules (> 2 cm), the modified K-TIRADSs maintained a very high sensitivity for detecting malignancy (98%). Conclusion: The modified K-TIRADSs significantly reduced the rate of unnecessary biopsies for small (1–2 cm) nodules while maintaining a very high sensitivity for malignancy for large (> 2 cm) nodules.

Increased Expression of c-jun in the Bile Acid-Induced Apoptosis in Mouse F9 Teratocarcinoma Stem Cells

Baek, Jin-Hyen,Kang, Chang-Mo,Chung, Hae-Young,Park, Myung-Hwan,Kim, Kyu-Won Korean Society for Biochemistry and Molecular Biol 1996 Journal of biochemistry and molecular biology Vol.29 No.1

Ursodeoxycholic acid (UDCA) and lithocholic acid (LCA), secondary bile acids, have been shown to have a cell differentiation activity in mouse F9 teratocarcinoma stem cells. Treatment with bile acids induced morphological changes, including cytoplasmic and nuclear membrane blebbing, aggregation of organelles, and chromatin condensation, corresponding to apoptosis. Moreover, the bile acids induced intemucleosomal DNA fragmentation, a hallmark of apoptosis. In addition, the expression of c-jun was increased, but that of c-myc and laminin was decreased during apoptosis induced by the bile acids in F9 cells. These results suggest that the bile acids can induce apoptosis in F9 cells. Furthermore, the c-jun expression may be related to the apoptosis induced by UDCA or LCA in F9 cells.

Sonographic Diagnosis of Cervical Lymph Node Metastasis in Patients with Thyroid Cancer and Comparison of European and Korean Guidelines for Stratifying the Risk of Malignant Lymph Node

Chung Sae Rom,Baek Jung Hwan,Rho Yun Hwa,Choi Young Jun,Sung Tae-Yon,Song Dong Eun,Kim Tae Yong,Lee Jeong Hyun 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.11

Objective: To evaluate the ultrasonography (US) features for diagnosing metastasis in cervical lymph nodes (LNs) in patients with thyroid cancer and compare the US classification of risk of LN metastasis between European and Korean guidelines. Materials and Methods: From January 2014 to December 2018, US-guided fine-needle aspiration was performed on 836 LNs from 714 patients for the preoperative nodal staging of thyroid cancer. The US features of LNs were retrospectively reviewed for the following features: size, presence of hilum, margin, orientation, cystic change, punctate echogenic foci (PEF), large echogenic foci, eccentric cortical thickening, abnormal vascularity, and cortical hyperechogenicity. A multiple logistic regression analysis was performed to identify the independent US features for the diagnosis of metastatic LNs. The diagnostic performance of independent US features was subsequently evaluated. LNs were categorized according to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and European Thyroid Association (ETA) guidelines, and the correlation between the two sets of classifications was assessed. Results: Absence of the hilum, presence of cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity were independent US features of metastatic LNs. Cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity showed high specificity (86.8%–99.6%). The absence of the hilum had the highest sensitivity yet low specificity (66.4%). When LNs were classified according to the ETA guidelines and K-TIRADS, they yielded similar categorizations of malignancy risks and were strongly correlated (Spearman coefficient, 0.9766 [95% confidence interval, 0.973–0.979]). According to the ETA guidelines, 9.8% (82/836) of LNs were classified as “not specified.” Conclusion: Absence of hilum, cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity were independent US features suggestive of metastatic LNs in thyroid cancer. Both K-TIRADS and the ETA guidelines provided similar risk stratification for metastatic LNs with a high correlation; however, the ETA guidelines failed to classify 9.8% of LNs into a specific risk stratum. These results may provide a basis for revising LN classification in future guidelines.