Structural Analysis of Exosomes Using Different Types of Electron Microscopy

Choi, Hyosun,Mun, Ji Young Korean Society of Microscopy 2017 Applied microscopy Vol.47 No.3

Negative staining has been traditionally used for exosome imaging; however, the technique is limited to surface topology only and can cause staining artifacts. Therefore, to analyze the internal structure of exosomes, we employed a method of block preparation, thin sectioning, and electron tomography. In addition, an automatic serial sectioning technique with 15-nm thickness through focused ion beam was employed to observe the three-dimensional structure of exosomes of various sizes. Cryo-transmission electron microscopy revealed the near-to-native structure of exosomes.

전자선단층촬영 관상동맥석회화 정량분석과 관상동맥질환의 비교

이종민,강덕식 慶北大學校 醫科大學 1997 慶北醫大誌 Vol.38 No.2

목적 : 전자선단층촬영(EBT)으로 관찰이 가능한 관상동맥의 석회화병변을 정량화 하여 동맥경화성 관상동맥질환과 비교 분석하고 그 연관성을 알아보고자 하였다. 대상 및 방법 : 총 53명의 입원 및 외래환자들을 대상으로 EBT를 시행한 후 201Th 심근스캔, 운동부하 심전도검사, 또는 관상동맥조영술을 실시하여 관상동맥질환을 검사하였다. Kendos와 Rumberger에 의해 제안된 석회화수치환산표를 이용하여 EBT 검사결과를 Negative, Low risk, Moderate risk, high riks, very high risk group으로 구분하고 기존의 검사방법을 이용한 검사결과를 정상군, 무증상질환군, 유증상질환군으로 나누어 서로 비교하였다. 결과 : 정상군에서 관상동맥석회수치검사상 negative group이 26명(76%), low risk group이 4명(12%), moderate risk group과 high risk group이 각각 2명(6%)이었고 무증상질환군에서는 High risk group이 1명(33%), very high risk group이 2명(66%)이었다. 또한 유증상질환군에서는 very high risk group이 7명(44%), high risk group이 4명(25%), moderate risk group이 1명(6%), low risk group이 3명(19%), negative group이 1명(6%)으로 비교적 다양한 분포를 보였다. moderate risk group이하와 그 초과 group들을 묶어 크게 두 집단으로 나누고 정상군과 무증상질환군을 비교한 결과 민감도는 100%였고 특이도는 94%였다. 또한 정상군과 질환군을 비교할 경우 민감도는 74%이고 특이도는 94%였다. 결론 : EBT를 이용한 관상동맥석회화검사는 정상군과 무증상질환군을 구분함으로써 동맥경화성관상동맥질환의 조기발견에 도움이 될 것으로 생각된다. 그러나 더 많은 환자를 대상으로 한 연구가 지속되어야 하겠다. To analyze the relationship between the presence of obstructive coronary arterial disease and the Electron-beam tomographic coronary calcium quantitation, we have examined 53 patients with EBT scan and conventional studies such as 201Th-MIBI scan, exercise-stress EKG and coronary angiography. We divided the coronary calcium values into 5 groups according to Kondos-Rumberger recommendation (unpublished data) and compared them with the results of conventional studies for coronary arterial disease. As results, we could find that normal patients (94%) distributed in groups below moderate risk group, and all asymptomatic positive patients were included in high and very high risk groups. Although larger portion of symptomatic positive patients (69%) were in very high and high risk groups, the distribution was quite broad. Due to the limitation in patient number, statistical data analysis was not performed. However, by combining five coronary calcium score groups into two groups, we carried out two-by-two table analysis. The result was then compared with (1) normal and asymptomatic positive group, and (2) normal and disease-positive group. In these analyses the sensitivity for asymptomatic positive group was 100% and the specificity was 94%. The sensitivity for disease-positive group was 74% and the specificity was 94%. In conclusion, EBT coronary calcium quantitation was useful to differentiate asymptomatic positive patients from normal one and subsequently was valuable in early diagnosis of atherosclerotic coronary areterial disease. However, more-extensive study will be indispensible to acquire more definite result.

전자선 단층 촬영을 이용한 폐종괴의 관류측정$^1$

최규옥,Choe, Gyu-Ok 대한영상의학회 2002 대한영상의학회지 Vol.46 No.2

목적: 전자선단층촬영기를 이용하여 폐종괴의 관류 측정 및 관류 유형을 분석하고 폐종괴의 감별 진단에 도움이 되는지 알아보고자 한다. 대상과 방법: 28개의 폐종괴를 대상으로 하여 전향적 연구를 시행하였다. 남자가 23명이었고 여자가 5명이었으며 평균 연령은 57세였다.Multislice flow mode로 폐관류를 측정하고 관류유형을 분석하였다. 관류 영상은 4기로 이루어졌다. 조영 전 병변의 HU, 병변의 관류량, 최대 조영 증가 HU 및 최대 조영 증가 시기, 지연기에서의 평균 밀도 및 1기 최대치에 대한 %감소율을 구하고 병변의 진단에 따라 비교, 분석하였다. 결과: 19개의 종괴는 악성 종양으로,9개는 양성 병변으로 진단되었고 악성 종양 중 14개의 병변은 원발성 폐암으로 5개의 병변은 폐전이로 진단되었다. 악성 종양이 양성 종괴보다 유의하게 높은 관류량(p<0.001)및 제2기 평균 밀도 (p<0.05)와 유의하게 짧은 최대 조영 증가 시기(p<0.05)를 보였다.원발성 폐암 (n=14)이 양성 종괴보다 유의하게 높은 관류량 (p<0.001) 및 제2기 평균 밀도 (p<0.05)를 보였다. 원발성 폐암과 폐전이는 유의한 관류량 및 관류 유형의 차이를 보이지 않았다. 결론: 전자선단층촬영을 이용한 폐종괴의 관류 측정 및 관류 유형의 분석은 악성 및 양성 폐종양의 감별 진단에 유용한 정보를 제공한다. Purpose: To investigate the perfusion of pulmonary nodules and the flow pattern revealed by electron beam tomography (EBT), and to evaluate their usefulness in the differential diagnosis of pulmonary nodules. Materials and Methods: A prospective perfusion study involving 28 nodules in 23 men and five women (meanage, 57 years) was performed using EBT with the multislice flow mode. There were four phases. Precontrast density (Hounsfield units, HU) in phase 0; perfusion, peak HU and time to peak in phase 1; and mean HU and percentage decrease of HU to peak HU of phase 1 in phases 2 and 3 were measured and compared according Results: Malignancy was diagnased in 19 cases [primary lung cancer (n=14); metastatic nodules (n=5)], while nine nodules were benign. Perfusion was significantly higher in malignant nodules than in benign (P<0.001) and a higher mean delay 1 HU (P<0.05) and a significantly short time to peak (P<0.05) were recorded in malignant nodules. In primary lung cancer cases, perfusion was significantly high compared with benign nodules(P<0.001), and a mean delay 1 HU was observed (P<0.05). There was no significant difference in perfusion Conclusion: Perfusion and flow pattern data measured by EBT can provide the useful information for differentiation between malignant and benign pulmonary nodules.

Design and 3D-printing of titanium bone implants: brief review of approach and clinical cases

Vladimir V. Popov Jr.,Gary Muller-Kamskii,Aleksey Kovalevsky,Georgy Dzhenzhera,Evgeny Strokin,Anastasia Kolomiets,Jean Ramon 대한의용생체공학회 2018 Biomedical Engineering Letters (BMEL) Vol.8 No.4

Additive manufacturing (AM) is an alternative metal fabrication technology. The outstanding advantage of AM (3Dprinting,direct manufacturing), is the ability to form shapes that cannot be formed with any other traditional technology. 3D-printing began as a new method of prototyping in plastics. Nowadays, AM in metals allows to realize not only netshapegeometry, but also high fatigue strength and corrosion resistant parts. This success of AM in metals enables newapplications of the technology in important fields, such as production of medical implants. The 3D-printing of medicalimplants is an extremely rapidly developing application. The success of this development lies in the fact that patientspecificimplants can promote patient recovery, as often it is the only alternative to amputation. The production of AMimplants provides a relatively fast and effective solution for complex surgical cases. However, there are still numerouschallenging open issues in medical 3D-printing. The goal of the current research review is to explain the whole technologicaland design chain of bio-medical bone implant production from the computed tomography that is performed by thesurgeon, to conversion to a computer aided drawing file, to production of implants, including the necessary post-processingprocedures and certification. The current work presents examples that were produced by joint work of Polygon MedicalEngineering, Russia and by TechMed, the AM Center of Israel Institute of Metals. Polygon provided 3D-planning and 3Dmodellingspecifically for the implants production. TechMed were in charge of the optimization of models and theymanufactured the implants by Electron-Beam Melting (EBM ), using an Arcam EBM A2X machine.

Recent advances in electron microscopy for the diagnosis and research of glomerular diseases

( Kazuho Honda ),( Takashi Takaki ),( Dedong Kang ) 대한신장학회 2023 Kidney Research and Clinical Practice Vol.42 No.2

Recent technical advances in the detection of backscattered electrons during scanning electron microscopy (SEM) have improved resolution and have provided several new technologies for research and clinical practice in kidney disease. The advances include three-dimensional (3D) electron microscopy (3D-EM), correlative light and electron microscopy (CLEM), low-vacuum SEM (LVSEM), and scanning transmission electron microscopy (STEM). 3D-EM analysis used to be laborious, but recently three different technologies, serial block-face SEM, focused ion beam SEM, and array tomography, have made 3D-EM easier by automating sectioning and the subsequent image acquisition in an SEM. CLEM is a method to correlate light microscopic images, especially immunofluorescent and electron microscopy images, providing detailed ultrastructure of the area of interest where the immunofluorescent marker is located. LVSEM enables the use of SEM on materials with poor electron conductivity. For example, LVSEM makes it possible for high resolution, 3D observation of paraffin sections. Finally, STEM is a method to observe ultrathin sections with improved resolution by using the focused electron beam scanning used in SEM and not the broad electron beam used in transmission electron microscopy. These technical advances in electron microscopy are promising to provide plenty of novel insights for understanding the pathogenesis and diagnosis of various glomerular diseases.

전자선 단층 촬영기를 이용한 코골이 환자의 역동적 상기도 측정

예미경,신승헌,김창균,이상흔,이종민,최재갑 대한이비인후과학회 2003 대한이비인후과학회지 두경부외과학 Vol.46 No.2

Background and Objectives:The upper airway caliber shows rhythmic changes according to the respiratory cycle. The dyna-mic imaging technique is needed to demonstrate nonfixed oropharyngeal obstruction in patients with snoring and/or obstructive from the dynamic view of the oropharynx and to estimate the usefulnes of electron beam tomography (EBT) in the snoring and/or obstructive sleep apnea patients. Materials and Method:The upper airway was scanned in 18 patients with snoring by using EBT while awake, asleep, pre and post UPPP (six patients), and pre and post oral appliance (seven patients) during at least two full respiratory cycles. Results:The oropharyngeal stenosis and collapsibility were increased during slep, especialy in the minimum cross sectional area level. In most cases, the sites of stenosis of wakefulness and slep did not coincide. The degre of stenosis as well as collapsibility of the oropharynx were reduced after UPPP and oral appliance. Conclusion:The dynamic study during sleep is needed to evaluate slep induced airway disease. EBT has the potential to provide information quickly and non-invasively on upper airway dynamics and has certain definite advantages over conventional studies. (Korean J Otolaryngol 2003 ;46 :120-5)

전자선 단층촬영의 관상동맥 석회수치와 폐쇄성 관상동맥질환의 상관관계에 관한 연구

이상훈 대한영상의학회 1998 대한영상의학회지 Vol.39 No.2

Effect of Total Collimation Width on Relative Electron Density, Effective Atomic Number, and Stopping Power Ratio Acquired by Dual-Layer Dual-Energy Computed Tomography

정성문,김빛별,윤은택,김정인,박종민,최창헌 한국의학물리학회 2021 의학물리 Vol.32 No.4

Purpose: This study aimed to evaluate the effect of collimator width on effective atomic number (EAN), relative electron density (RED), and stopping power ratio (SPR) measured by dual-layer dual-energy computed tomography (DL-DECT). Methods: CIRS electron density calibration phantoms with two different arrangements of material plugs were scanned by DL-DECT with two different collimator widths. The first phantom included two dense bone plugs, while the second excluded dense bone plugs. The collimator widths selected were 64 mm×0.625 mm for wider collimators and 16 mm×0.625 mm for narrow collimators. The scanning parameters were 120 kVp, 0.33 second gantry rotation, 3 mm slice thickness, B reconstruction filter, and spectral level 4. An image analysis portal system provided by a computed tomography (CT) manufacturer was used to derive the EAN and RED of the phantoms from the combination of low energy and high energy CT images. The EAN and RED were compared between the images scanned using the two different collimation widths. Results: The CT images with the wider collimation width generated more severe artifacts, particularly with high-density material (i.e., dense bone). RED and EAN for tissues (excluding lung and bones) with the wider collimation width showed significant relative differences compared to the theoretical value (4.5% for RED and 20.6% for EAN), while those with the narrow collimation width were closer to the theoretical value of each material (2.2% for EAN and 2.3% for RED). Scanning with narrow collimation width increased the accuracy of SPR estimation even with high- density bone plugs in the phantom. Conclusions: The effect of CT collimation width on EAN, RED, and SPR measured by DL-DECT was evaluated. In order to improve the accuracy of the measured EAN, RED, and SPR by DL-DECT, CT scanning should be performed using narrow collimation widths.

The Effect of Mandibular Protrusion on Dynamic Changes in Oropharyngeal Caliber

정재광,최재갑,허윤경 대한안면통증∙구강내과학회 2010 Journal of Oral Medicine and Pain Vol.35 No.3

The purpose of this study was to determine the sites of narrowing/obstruction and to measure the regional severity of narrowing through the evaluation of dynamic changes in upper-airway of healthy subjects. The selected 9 subjects were proved not to have any sleep-related disorder such as snoring or obstructive sleep apnea through clinical examination, radiological examination, sleep study with a portable recording system. Afterward, the Electron Beam Tomography was performed during the waking and sleeping state of subjects, with their mandible in resting and protruded position. Intravenous injection of DormicumⓇ was used for the induction of sleep. The maximum and minimum cross-sectional areas at each airway level during tidal ventilation were measured and the Collapsibility Index for each level of cross-section was also computed. In a comparison with results under variable conditions, the result was showed that the significant difference between each airway level divided with upper, middle, lower region of upper airway is not observed in the average minimum cross-sectional areas and Collapsibility Index. The significant difference only between in wake and sleep state was observed in the average minimum cross-sectional area at the lower region. Also, in wake state, the significant difference between resting and protrusive position of mandible for the average minimum was also observed in cross-sectional area at middle region. In sleep state, no significant difference between resting and protrusive position of mandible was observed in cross-sectional area and the Collapsibility Index.

관동맥 석회치 검사의 역할 : 폐쇄성 관동맥 질환의 예방 및 조기 발견

최규옥 대한순환기학회 1997 Korean Circulation Journal Vol.27 No.5