• Progress in Medical Physics
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• v.17 no.2
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• pp.61-66
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• 2006

To evaluate the T1, T2 magnetic relaxation properties of water molecule according to molecular weight of paramagnetic complex. 4-aminomethyicyclohexane carboxylic acid (0.63 g, 4 mmol) was mixed with the suspension solution of DMF (15 ml) and DTPA-bis-anhydride (0.71 g, 2 mmol) to synthesize the ligand. The ligand was then mixed with $Gd_2O_3$ (0.18 g, 0.5 mmol) to synthesize Gd-chelate. For the measurement of magnetic relaxivity of paramagnetic compounds, the compounds were diluted to 1 mM and then the relaxation times were measured at 1.57 (64 MHz). Inversion-recovery pulse sequence was employed for T1 relaxation measurement and CPMG (Carr-Purcell-Meiboon-Gill) pulse sequence was employed for T2 relaxation measurement. In case of inversion recovery sequence, total 35 images with different inversion time(T1)s ranging from 50 msec to 1,750 msec. To estimate the relaxation times, the signal intensity of each sample was measured using region of Interest (ROI) and then fitted by non-linear least square method to yield T1, T2 relaxation times and also R1 and R2. Compared to T1=($205.1{\pm}2.57$) msec and T2=($209.4{\pm}4.28$) msec of Omniscan (Gadodiamide), which is commercially available paramagnetic MR agent, T1 and T2 values of new paramagnetic complexes were reduced along with their molecular weight. That is, T1 value was ranged from $(96.35{\pm}2.04)\;to\;(79.38{\pm}1.55)$ msec and T2 value was ranged from $(91.02{\pm}2.08)\;to\;(76.66{\pm}1.84)$ msec. Among new paramagnetic complexes, there is a tendency that the R1 and R2 increase as the molecular weight is increases. As molecular weight of paramagnetic complex increases, T1 and T2 relaxation times reduce and thus the increase of relaxivity (R1 and R2) Is proportional to molecular weight.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.111-112
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• 2009

Diamond-like carbon (DLC) is a convenient term to indicate the compositions of the various forms of amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon and tetrahedral amorphous carbon (a-C:H and ta-C:H). The a-C film with disordered graphitic ordering, such as soot, chars, glassy carbon, and evaporated a-C, is shown in the lower left hand corner. If the fraction of sp3 bonding reaches a high degree, such an a-C is denoted as tetrahedral amorphous carbon (ta-C), in order to distinguish it from sp2 a-C [2]. Two hydrocarbon polymers, that is, polyethylene (CH2)n and polyacetylene (CH)n, define the limits of the triangle in the right hand corner beyond which interconnecting C-C networks do not form, and only strait-chain molecules are formed. The DLC films, i.e. a-C, ta-C, a-C:H and ta-C:H, have some extreme properties similar to diamond, such as hardness, elastic modulus and chemical inertness. These films are great advantages for many applications. One of the most important applications of the carbon-based films is the coating for magnetic hard disk recording. The second successful application is wear protective and antireflective films for IR windows. The third application is wear protection of bearings and sliding friction parts. The fourth is precision gages for the automotive industry. Recently, exciting ongoing study [1] tries to deposit a carbon-based protective film on engine parts (e.g. engine cylinders and pistons) taking into account not only low friction and wear, but also self lubricating properties. Reduction of the oil consumption is expected. Currently, for an additional application field, the carbon-based films are extensively studied as excellent candidates for biocompatible films on biomedical implants. The carbon-based films consist of carbon, hydrogen and nitrogen, which are biologically harmless as well as the main elements of human body. Some in vitro and limited in vivo studies on the biological effects of carbon-based films have been studied [$2{\sim}5$].The carbon-based films have great potentials in many fields. However, a few technological issues for carbon-based film are still needed to be studied to improve the applicability. Aisenberg and Chabot [3] firstly prepared an amorphous carbon film on substrates remained at room temperature using a beam of carbon ions produced using argon plasma. Spencer et al. [4] had subsequently developed this field. Many deposition techniques for DLC films have been developed to increase the fraction of sp3 bonding in the films. The a-C films have been prepared by a variety of deposition methods such as ion plating, DC or RF sputtering, RF or DC plasma enhanced chemical vapor deposition (PECVD), electron cyclotron resonance chemical vapor deposition (ECR-CVD), ion implantation, ablation, pulsed laser deposition and cathodic arc deposition, from a variety of carbon target or gaseous sources materials [5]. Sputtering is the most common deposition method for a-C film. Deposited films by these plasma methods, such as plasma enhanced chemical vapor deposition (PECVD) [6], are ranged into the interior of the triangle. Application fields of DLC films investigated from papers. Many papers purposed to apply for tribology due to the carbon-based films of low friction and wear resistance. Figure 1 shows the percentage of DLC research interest for application field. The biggest portion is tribology field. It is occupied 57%. Second, biomedical field hold 14%. Nowadays, biomedical field is took notice in many countries and significantly increased the research papers. DLC films actually applied to many industries in 2005 as shown figure 2. The most applied fields are mold and machinery industries. It took over 50%. The automobile industry is more and more increase application parts. In the near future, automobile industry is expected a big market for DLC coating. Figure 1 Research interests of carbon-based filmsFigure 2 Demand ratio of DLC coating for industry in 2005. In this presentation, I will introduce a trend of carbon-based coating research and applications.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.142-148
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• 2003

Purpose: This study was performed to evaluate the operative results of osteochondritis dissecans treated with autogenous osteochondral grafts. Materials and Methods: From May 1990 to May 2000, this study included 13 patients, 17 cases treated with autogenous osteochondral grafts. The mean age of patients at operation was 23.4 years (range,20 to 32 years), all cases were men, and the mean follow-up was for 24.2 months (range, 12 to 110 months). Treatment was done by open or arthroscopic method using with Osteochondral Autograft Transfer System (OATS, Arthrex, USA). Results: Trauma history existed in all cases, and major trauma history in 7 cases, and minor repetitive in 10 cases. The involved sites of lesion were medial femoral condyle in 11 cases, in which extended classic site was 9 cases, inferocentral site was 2 cases, and lateral femoral condyle in 6 cases, in which all cases were inferocentral site. Magnetic resonance imaging (MRI) staging was stage II in 1 case, stage III in 11 cases, stage IV in 5 cases, and arthroscopic staging was stage III in 12 cases, stage IV in 5 cases. The mean lesion size was 3.19$cm^2$ (range, 1 to 8$cm^2$). Clinical results evaluated with grading system by Aichroth, were excellent in 3 cases (18$\%$), good in 11 cases (65$\%$), moderate in 2 cases (12V), poor in 1 case (5$\%$), which revealed satisfactory results in 83$\%$. Congruent articular surface, satisfactory articular thickness, and no loosening or subsidence was evidenced by follow-up MRI or arthroscopic finding. Conclusion: Autogenous osteochondral grafts can be an alternative treatment in lesions larger than 1$cm^2$ in size, unstable lesion, and involvement of weight-bearing articular surface. Long term follow-up will be needed for the final efficacy of autogenous osteochondral grafts.

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.157-168
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• 2020

Advancements in segmentation methodology has made automatic segmentation of brain structures using structural images accurate and consistent. One method of automatic segmentation, which involves registering atlas information from template space to subject space, requires a high quality atlas with accurate boundaries for consistent segmentation. The Allen Mouse Brain Atlas, which has been widely accepted as a high quality reference of the mouse brain, has been used in various segmentations and can provide accurate coordinates and boundaries of mouse brain structures for tractography. Through probabilistic tractography, diffusion tensor images can be used to map comprehensive neuronal network of white matter pathways of the brain. Comparisons between neural networks of mouse and human brains showed that various clinical tests on mouse models were able to simulate disease pathology of human brains, increasing the importance of clinical mouse brain studies. However, differences between brain size of human and mouse brain has made it difficult to achieve the necessary image quality for analysis and the conditions for sufficient image quality such as a long scan time makes using live samples unrealistic. In order to secure a mouse brain image with a sufficient scan time, an Ex-vivo experiment of a mouse brain was conducted for this study. Using FSL, a tool for analyzing tensor images, we proposed a semi-automated segmentation and tractography analysis pipeline of the mouse brain and applied it to various mouse models. Also, in order to determine the useful signal-to-noise ratio of the diffusion tensor image acquired for the tractography analysis, images with various excitation numbers were compared.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.293-300
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• 1994

It is well known that Tc-99m HMPAO brain SPECT can reflect the functional lesions better than X-ray computerized tomography(CT) and magnetic resonance imaging(MRI) in the cerebral disorders. In order to evaluate the clinical utilities of Tc-99m HMPAO brain SPECT in patients with post-traumatic chronic organic mental disorder(OMD), we included 28 patients diagnosed as OMD in department of psychiatry after traumatic head injury. And we compared the results of Tc-99m HMPAO SPECT with those of MRI, EEG and MINI mental status ex amination(MMSE). The results were as follows 1) All patients diagnosed as OMD showed diffuse or focal decreased cerebral perfusion on Tc-99m HMPAO SPECT. 2) Most frequent lesion on brain Tc-99m HMPAO SPECT was decreased perfusion on both frontal lobe. And most frequent lesion on brain Tc-99m HMPAO SPECT showing normal brain MRI result was also decreased both frontal perfusion. 3) Eight of 28 patients showed focal brain MRI lesions(4 small frontal hygroma, 3 small cerebral infarction and 1 cerebellar encephalomalacia) which were not detected in brain Tc-99m HMPAO SPECT. 4) The patients showing less than 20 points on MMSE disclosed abnormal results of EEG more frequently than those disclosing more than 20 points. In conclusion, we think that Tc-99m HMPAO brain SPECT is sensitive method to detect functional lesions of the brains in patients with chronic post-traumatic organic mental disorder.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.180-188
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• 2014

It is very important accurate diagnosis and quick treatment in cerebrovascular disease, i.e. stenosis or occlusion that could be caused by risk factors such as poor dietary habits, insufficient exercise, and obesity. Time-of-flight magnetic resonance angiography (TOF-MRA), it is well known as diagnostic method without using contrast agent for cerebrovascular disease, is the most representative and reliable technique. Nevertheless, it still has measurement errors (also known as overestimation) for length of stenosis and area of occlusion in celebral infarction that is built by accumulation and rupture of plaques generated by hemodynamic turbulence. The purpose of this study is to show clinical trial feasibility for 3D-SPACE T2, which is improved by using signal attenuation effects of fluid velocity, in diagnosis of cerebrovascular disease. To model angiostenosis, strictures of different proportions (40%, 50%, 60%, and 70%) and virtual blood stream (normal saline) of different velocities (0.19 ml/sec, 1.5 ml/sec, 2.1 ml/sec, and 2.6 ml/sec) by using dialysis were made. Cross-examinations were performed for 3D-SPACE T2 and TOF-MRA (16 times each). The accuracy of measurement for length of stenosis was compared in all experimental conditions. 3D-SPACE 2T has superiority in terms of accuracy for measurements of the length of stenosis, compared with TOF-MRA. Also, it is robust in fast blood stream and large stenosis than TOF-MRA. 3D-SPACE 2T will be promising technique to increase diagnosis accuracy in narrow complex lesions as like two cerebral small vessels with stenosis, created by hemodynamic turbulence.

• Journal of Chest Surgery
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• v.33 no.12
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• pp.941-947
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• 2000

Background: Central nervous system complication after coronary artery bypass grafting(CABG) is one of the major prognostic determinants and the use of the cardiopulmonary bypass(CPB) may increase the incidence of this devastating complication. In this study, the outcomes after off-pump CABG were studied and compared with those following the conventional CABG using CPB. Material and Method: Among the consecutive isolated CABG's performed in SNUH during Feb. 1995 and Jun. 1999, 338 coronary artery bypass grafting were divided into two groups. 223 patients underwent CABG using the CPB(Group I), and 115 patients underwent CABG without CPB(OPCAB)(Group II). All patients enrolled in this study received extensive preoperative examinations including thorough neurologic examination before and after surgery, transcranial doppler study, carotid duplex ultrasonography, and magnetic resonance angiography if necessary. Central nervous system(CNS) complications were defined as stroke, seizure, metabolic or hypoxic encephalopathy and transient delirium after surgery. Result: There were 61 cases(27.3%) who developed postoperative CNS complication in Group I, whereas 8 cases(7.0%) of CNS complications developed postoperatively in group II(p<0.05). Statistically significant predictors of postoperative CNS complications in group I were age and the use of cardiac assist devices perioperatively. Conclusion: This study suggested that omitting the use of CPB in CABG resulted in significant decrease of the postoperative CNS complications. OPCAB should be more widely applied especially to the elderly who have preexisting cerebrovascular disease.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.154-163
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• 2015

Purpose: Osteoarticular infections in children and adolescents are important because it can cause functional compromise if appropriate treatment is delayed. Therefore, this study was designed to describe the clinical presentations and causative organisms of osteoarticular infections in children and adolescents in order to propose early diagnosis method and an appropriate empiric antimicrobial therapy. Methods: Forty-two medical records were reviewed retrospectively, which were confirmed as osteomyelitis (OM) or septic arthritis (SA) at Department of Pediatrics or Orthopedic Surgery in patients under 18 years old of Ewha Womans University Mokdong Hospital from March 2008 to March 2015. Results: We identified 21 cases of OM, 13 cases of SA and 8 cases of OM with SA. There were 31 males and 11 females and mean age was 7.1 years old. The most common symptoms were pain and tenderness of involved site. Major involved bones were femur (10 cases, 34.5%), tibia (7 cases, 24.1%) and major involved joints were hip (9 cases, 42.9%), and knee (5 cases, 23.8%). Increased serum C-reactive protein and erythrocyte sedimentation rate were observed in 37 cases (88.1%) respectively. Magnetic resonance imaging was performed in 40 cases among 42 cases and was used to demonstrate osteoarticular infections and other adjacent infections. Nine cases (23.7%) among 38 cases and 20 cases (50.0%) among 40 cases were positive in blood culture and infected site culture respectively. The most common causative organism was Staphylococcus aureus, which was represented in 22 cases (75.9%), of which nine cases (40.9%) were resistant to methicillin. Conclusions: S. aureus was the most common causative organism of osteoarticular infections in children and adolescents and the proportion of MRSA was high in this study. Therefore, we recommend vancomycin as the first empiric antimicrobial therapy and suggest that further study is necessary to elucidate an appropriate guideline for treatment which takes into account MRSA proportion.

• Journal of the Korean Society of Radiology
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• v.5 no.4
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• pp.189-194
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• 2011

This study used magnetic resonance diffusion tensor imaging (DTI) to quantitatively analyze the neural fiber tractography according to the age of normal corpus callosum and to evaluate of usefulness. The research was intended for the applicants of 60 persons that was in a good state of health with not brain or other disease. The test parameters were TR: 6650 ms, TE: 66 ms, FA: $90^{\circ}$, NEX: 2, thickness: 2 mm, no gap, FOV: 220 mm, b-value: $800s/mm^2$, sense factor: 2, acquisition matrix size: $2{\times}2{\times}2mm^3$, and the test time was 3 minutes 46 seconds. The evaluation method was constructed the color-cored FA map include to the skull vertex from the skull base in scan range. We set up the five ROI of corpus callosum of genu, anterior-mid body, posterior-mid body, isthmus, and splenium, tracking, respectively, and to quantitatively measured the length of neural fiber. As a result, the length of neural fiber, for the corpus callosum of genu was 20's: $61.8{\pm}6.8$, 30's: $63.9{\pm}3.8$, 40's: $65.5{\pm}6.4$, 50's: $57.8{\pm}6.0$, 60's: $58.9{\pm}4.5$, more than 70's: $54.1{\pm}8.1mm$, for the anterior-mid body was 20's: $54.8{\pm}8.8$, 30's: $58.5{\pm}7.9$, 40's: $54.8{\pm}7.8$, 50's: $56.1{\pm}10.2$, 60's: $48.5{\pm}6.2$, more than 70's: $48.6{\pm}8.3mm$, for the posterior-mid body was 20's: $72.7{\pm}9.1$, 30's: $61.6{\pm}9.1$, 40's: $60.9{\pm}10.5$, 50's: $61.4{\pm}11.7$, 60's: $54.9{\pm}10.0$, more than 70's: $53.1{\pm}10.5mm$, for the isthmus was 20's: $71.5{\pm}17.4$, 30's: $74.1{\pm}14.9$, 40's: $73.6{\pm}14.2$, 50's: $66.3{\pm}12.9$, 60's: $56.5{\pm}11.2$, more than 70's: $56.8{\pm}11.3mm$, and for the splenium was 20's: $82.6{\pm}6.8$, 30's: $86.9{\pm}6.4$, 40's: $83.1{\pm}7.1$, 50's: $81.5{\pm}7.4$, 60's: $78.6{\pm}6.0$, more than 70's: $80.55{\pm}8.6mm$. The length of neural fiber for normal corpus callosum were statistically significant in the genu(P=0.001), posterior-mid body(P=0.009), and istumus(P=0.012) of corpus callosum. In order of age, the length of neural fiber increased from 30s to 40s, as one grows older tended to decrease. For this reason, the nerve cells of brain could be confirmed through the neural fiber tractography to progress actively in middle age.

• Journal of Acupuncture Research
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• v.22 no.3
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• pp.155-167
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• 2005

Objectives : The purpose of this study was to investigate the anti-inflammatory effect of Cobrotoxin on binding affinity of cobrotoxin with P50, $IKK{\alpa}$ and $IKK{\beta}$, activities of NF-${\kappa}B$, Cell viability of astrocyte, expressions of protein molecules of NF-${\kappa}B$ such as P50, P-$1{kappa}B$, $1{\kappa}B$ and iflammation related genes such as Cox-2, iNOS, cPLA2 in the SNP or LPS induced Inflammatory pathway of Rats' astrocytes. Methods : In this study, The expression of cytosolic phospholipase A2, Nitric oxcide, Cyclooxygenase-2 and inducible nitrogen oxide synthase was determined by western blotting with corresponding antibodies, and the generation of NF-${\kappa}B$ was assayed by EMSA method in astrocytes of rats. The Cell viability of astrocytes was determined by MTT assay, and Binding affinity of Cobrotoxin with P50, $IKK{\alpha}$ and $IKK{\beta}$ was assayed by Surface plasmon resonance analysis, and NF-${\kappa}B$ dependent luciferase activity was determined by luciferase analysis, and Uptake of cobrotoxin in astrocytes was identified by Confocal laser scanning microscope Results : 1. Compared with control, LPS-induced NF-${\kappa}B$ DNA binding activity was decreased significantly by 0.1, $0.5{\mu}g/m{\ell}$ of Cobrotoxin in Astrocyte. 2. Compared with control, LPS-induced NF-kB dependent luciferase expression was decreased significantly by 0.1, 0.5 and $1{\mu}g/m{\ell}$ of Cobrotoxin in Astrocyte. 3. Compared with control, SNP induced P50, $I{\kappa}B$ expressions in astrocyte were decreased significantly by 0.1, 0.5 and $1{\mu}g/m{\ell}$ of Cobrotoxin and P-$1{\kappa}B$ expression was decreased significantly by 0.5 and $1{\mu}g/m{\ell}$ of Cobrotoxin. 4. Compared with control, LPS induced P50, $1{\kappa}B$ expressions in astrocyte were decreased significantly by 0.5 and $1{\mu}g/m{\ell}$ of Cobrotoxin. 5. Compared with control, SNP induced Cox-2, iNOS, CPLA2 expressions in astrocyte were decreased significantly by $1{\mu}g/m{\ell}$ of Cobrotoxin. 6. Compared with control, LPS induced Cox-2, cPLA2 expressions in astrocyte were decreased significantly by 0.1, 0.5, $1{\mu}g/m{\ell}$ of Cobrotoxin and iNOS expression was decreased significantly by 0.5, $1{\mu}g/m{\ell}$ of Cobrotoxin. 7. Compared with $0.5{\mu}g/m{\ell}$ of Cobrotoxin, SNP-induced NF-${\kappa}B$ DNA bindins activity in astrocyte was increased significantly by Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 1mM and Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 5mM. 8. Compared with $0.5{\mu}g/m{\ell}$ of Cobrotoxin, LPS-induced NF-${\kappa}B$ DNA binding activity in astrocyte was increased significantly by Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 1mM, Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 5mM, Cobrotoxin $0.5{\mu}g/m{\ell}$with GSH 1mM and Cobrotoxin $0.5{\mu}g/m{\ell}$ with GSH 5mM 9. Compared with $0.1{\mu}g/m{\ell}$ of cobrotoxin, SNP induced P50 expressions in astrocyte were increased significantly by Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 1mM, Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 5mM Cobrotoxin $0.5{\mu}g/m{\ell}$ with GSH 1mM and Cobrotoxin $0.5{\mu}g/m{\ell}$ with GSH 5mM. 10. The uptake of the labeled cobrotoxin into the cells was shown under a confocal laser scanning microscope. cobrotoxin was uptaken into the membrane and nucleus of astrocytes. Conclusions : In summary, the present results demonstrate that cobrotoxin directly binds to sulfhydryl group of p50 and IKKS resulting In the reduction of translocation of p50 and IkB release, thereby inhibits activation of NF-${\kappa}B$, and suggest that pico to nanomolar range of cobrotoxin could inhibit the expression of genes in the NF-${\kappa}B$ signal pathway.