• Bulletin of the Korean Space Science Society
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• 한국우주과학회 1993년도 한국우주과학회보 제2권2호
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• pp.17-17
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• 1993

The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70${\pm}$1.32mmHg/min)compared to CF dialyzers(4.32${\pm}$0.55mmHg/min)(p<0.05). However, there was no observable difference in the UFR between the two dialyzers. Neither APD nor UFR showed any significant increase with an increasing number of reuses for up to more than 20reuses. A substantial number of failures observed in APD(larger than 20mmHe/min)on the reused dialyzers(2 out of 40 CP and S out 26 C-DAK) were attributed to the Possible damage on the fibers. The CF 15-11 HFDs which failed APD test did not show changes in the UFR compared to normal dialyzers indicating that APD is a more sensitive test than UFR test to evaluate the integrity of the fibers. 30527 T00401030527 ^x For quantitative measurement of reflected light from a clinical diagnostic strip, a prototype old reflectance photometer was designed. The strip loader and cassette were made to obtain more accurate reflectance parameters. The strip was illuminated at 45˚c through optical fiber and the intensity of reflected light was determined at rectanguLat angle using a photodiode. The kubelka-munk coefficient and reflection optical density were determined ar four different wavelengths(500,550,570 and 610nm) for blood glucose strip. For higher concentration than 300mg/41 about glucose, a saturation state of abforbance was observed at 500,550 and 570nm. The correlation between glucose concentration and parameters was the best at 610nm. 30535 T00401030535 ^x Radiation-induced fibrosarcoma tumors were grown on the flanks of C3H mice. The mice were divided into two groups. One group was injected with Photofrin II, intravenously (2.5mg/kg body weight). The other group received no Photofrin II. Mice from both groups were irradialed for approximately 15 minutes at 100,300, or 500 mW/cm2 with the argon (488nm/514.5 nm), dye(628nm) and gold vapor (pulsed 628 nm) laser light. A photosensitizer behaved as an added absorber. Under our experimental conditions, the presence of Photolfrin II increased surface temperature by at least 40% and the temperature rise due to 300 mW/cm2 irradiation exceeded values for hyperthermia. Light and temperature distributions with depth were estimated by a computer model. The model demonstrated the influence of wavelength on the thermal process and proved to be a valuable tool to investigate internal temperature rise. 30536 T00401030536 ^x We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs 3nd others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized tomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh IIci computer.The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal flare index are greater by the amount of approximately 8˚ and 0.5, respectively, (2) the shape of the isthmus cross section is more round, and (3) the distance between the teaser trochanter and the proximal border of the isthmus is shelter by about 15 mm. The results suggested that the femoral component suitable for Asians should be different from the currently-used components designed and manufactured mostly by European or American companies. 30537 T00401030537 ^x It is well known that nonlinear propagation characteristics of the wave in the tissue may give very useful information for the medical diagnoisis. In this paper, a new method to detect nonlinear propagation characteristics of the internal vibration in the tissue for the low frequency mechanical vibration by using bispectral analysis is proposed. In the method, low frequency vibration of f0( = 100Hz) is applied on the surface of the object, and the waveform of the internal vibration x (t) is measured from Doppler frequency modulation of silmultaneously transmitted probing ultrasonic waves. Then, the bispectra of the signal x (t) at the frequencies (f0, f0) and (f0, 2f0) are calculated to estimate the nonlinear propagation characteristics as their magnitude ratio, w here since bispectrum is free from the gaussian additive noise we can get the value with high S/N. Basic experimental system is constructed by using 3.0 MHz probing ultrasonic waves and the several experiments are carried out for some phantoms. Results show the superiority of the proposed method to the conventional method using power spectrum and also its usefulness for the tissue characterization. 30541 T00401030541 ^x This paper describes the implementation of a computerized radial pulse diagnosis by aids of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diagnosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed it. Then, we have got the characteristic parameters of radial pulse wave and also quantified that according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial pulse diagnosis system and then we confirmed the possibility for realization of automatic radial pulse diagnosis in korean traditional medicine. 30545 T00401030545 ^x Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, immunomagnetic cell separation. To synthesize microspheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio of synthesized microspheres was always smaller than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6~13 times higher than that of the microspheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin).The effect of the kind and the amount of surface functional group was also examined. 30575 T00401030575 ^x A medical image workstation was developed using multimedia technique. The system based on PC-486DX was designed to acquire medical images produced by medical imaging instruments and related audio information, that is, doctors' reporting results. Input information was processed and analyzed, then the results were presented in the form of graph and animation. All the informations of the system were hierarchically related with the image as the apex. Processing and analysis algorithms were implemented so that the diagnostic accuracy could be improved. The diagnosed information can be transferred for patient diagnosis through LAN(local area network). 30592 T00401030592 ^x In the conventional infrared imaging system, complex infrared lens systems are usually used for directing collimated narrow infrared beams into the high speed 2-dimensional optic scanner. In this paper, a simple reflective infrared optic system with a 2-dimensional optic scanner is proposed for the realization of medical infrared thermography system. It has been experimentally proven that the intfrared thermography system composed of the proposed optic system has the temperature resolution of 0.1˚c under the spatial resolution of lmrad, the image matrix size of 256 X 240, and tile imaging time of 4 seconds. 30593 T00401030593 ^x In this paper, MIIS (Medical Image Information System) has been designed and implemented using INGRES RDBMS, which is based on a client/server architecture. The implemented system allows users to register and retrieve patient information, medical images and diagnostic reports. It also provides the function to display these information on workstation windows simultaneously by using the designed menu-driven graphic user interface. The medical image compression/decompression techniques are implemented and integrated into the medical image database system for the efficient data storage and the fast access through the network. 30594 T00401030594 ^x In this paper, computerized BEAM was implemented for the space domain analysis of EEG. Trans-formation from temporal summation to two-dimensional mappings is formed by 4 nearest point inter-polaton method. Methods of representation of BEAM are two. One is dot density method which classify brain electrical potential 9 levels by dot density of gray levels and the other is colour method which classify brain electrical 12 levels by red-green colours. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily. In the frequency domain, the distribution of energy spectrum of a special band can easily be distinguished normality and abnormality. 30608 T00401030608 ^x Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer. The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with fwd complete blood count analyzers(Sysmex NE-8000 and Coulter STKS) for unidirectional data tansmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology. 30609 T00401030609 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atelocollagen was produced: The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength. 30618 T00401030618 ^x This paper is a study on the design of adptive filter for QRS complex detection. We propose a simple adaptive algorithm to increase capability of noise cancelation in QRS complex detection with two stage adaptive filter. At the first stage, background noise is removed and at the next stage, only spectrum of QRS complex components is passed. Two adaptive filters can afford to keep track of the changes of both noise and QRS complex. Each adaptive filter consists of prediction error filter and FIR filter The impulse response of FIR filter uses coefficients of prediction error filter. The detection rates for 105 and 108 of MIT/BIH data base were 99.3% and 97.4% respectively. 30619 T00401030619 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased. 30620 T00401030620 ^x We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate. 30621 T00401030621 ^x Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd:YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as Br.), and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased.To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained. 30622 T00401030622 ^x N1 and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. N1-N2 audiograms were made by means of regulating stimulant intensities in order to produce constant N1-N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip I5 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both noN1inear and active functions of the Cochlea can be monitored by N1-N2 audiograms. 30623 T00401030623 ^x In electrical impedance tomography(EIT), we use boundary current and voltage measurements toprovide the information about the cross-sectional distribution of electrical impedance or resistivity. One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.77 NMR machine. We implemented a resistivity mage reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the mage reconstruction algorithm and furture direction of the research. 30624 T00401030624 ^x A new method of digital image analysis technique for discrimination of cancer cell was presented in this paper. The object image was the Thyroid eland cells image that was diagnosed as normal and abnormal (two types of abnormal: follicular neoplastic cell, and papillary neoplastic cell), respectively. By using the proposed region segmentation algorithm, the cells were segmented into nucleus. The 16 feature parameters were used to calculate the features of each nucleus. A9 a consequence of using dominant feature parameters method proposed in this paper, discrimination rate of 91.11% was obtained for Thyroid Gland cells. 30625 T00401030625 ^x An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients. 30626 T00401030626 ^x Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluid mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further. Development of active elements which are essential in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult. 30627 T00401030627 ^x A method has been proposed for the fully automatic detection of left ventricular endocardial boundary in 2D short axis echocardiogram using geometric model. The procedure has the following three distinct stages. First, the initial center is estimated by the initial center estimation algorithm which is applied to decimated image. Second, the center estimation algorithm is applied to original image and then best-fit elliptic model estimation is processed. Third, best-fit boundary is detected by the cost function which is based on the best-fit elliptic model. The proposed method shows effective result without manual intervention by a human operator. 30628 T00401030628 ^x The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMf signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements. 30638 T00401030638 ^x A new neural network architecture for the recognition of patterns from images is proposed, which is partially based on the results of physiological studies. The proposed network is composed of multi-layers and the nerve cells in each layer are connected by spatial filters which approximate receptive fields in optic nerve fields. In the proposed method, patterns recognition for complicated images is carried out using global features as well as local features such as lines and end-points. A new generating method of matched filers representing global features is proposed in this network. 30659 T00401030659 ^x An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for charging high voltage capacitors, the weight and size of the magnetic nerve stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3,000 volts and switching time is about 100 msec. Experimental results or human nerve stimulations using the developed stimulator are presented. 30768 T00401030768 ^x In this paper, we describe the design methodology and specifications of the developed module-based bedside monitors for patient monitoring. The bedside monitor consists of a main unit and module cases with various parameter modules. The main unit includes a 12.1" TFT color LCD, a main CPU board, and peripherals such as a module controller, Ethernet LAN card, video card, rotate/push button controller, etc. The main unit can connect at maximum three module cases each of which can accommodate up to 7 parameter modules. They include the modules for electrocardiograph, respiration, invasive blood pressure, noninvasive blood pressure, temperature, and SpO2 with Plethysmograph.

• The Journal of the Korean bone and joint tumor society
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• 제11권2호
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• pp.134-140
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• 2005

Purpose: We evaluated the effectiveness of temporary using the extendible external fixator (EF) for lengthening of soft tissue that contracture caused by tumor prosthesis removal in the treatment of complications after limb salvage surgery like deep infection and loosening. Materials and Methods: Five patients six cases were included who underwent extendible EF (Dyna-extor(r)). EF was applied after insertion of half pin to the proximal and distal bone of defect area. EF lengthening started at third day of post-operation, above 2-3 mm per day in the range of no neurological sign. Results: The treatment area was three in femur and two in tibia. Mean age when the time of EF apply was 22.2 years old (range 15-29), but its primary limb salvage operation had done in 13.4 years old (range 9-19), therefore mean times of interval between initial tumor prosthesis reconstruction and temporary EF apply was 8.8 years (range 3-14). One patient had EF for 150 days with 7.2 cm lengthening. Others 5 cases of 4 patients had EF for mean 37 days (range 25-50) and mean soft tissue lengthening was 5.8 cm. Three patients underwent re-insertion of tumor prosthesis and two patients underwent knee fusion as final operation and showed no evidence of infection through mean 22 months follow up period. Conclusion: Temporary using of extendible EF is an effective method for correction of leg shortening which occurred by soft tissue contracture in the complications of limb salvage operation or their treatment process, and it could be provide easily application of tumor prosthesis and knee fusion as final operation.

• Journal of Chest Surgery
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• 제38권10호
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• pp.685-692
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• 2005

Background: Wall motion abnormalities may be a significant predictor for long-term survival after coronary bypass surgery (CABG). The aim of this study is to see whether post-infarction wall motion abnormality of left ventricle affect on the long-term survival after CABG. Material and Method: One-hundred and thirty-three patients (male/female, 92/41) undergoing CABG more than 9 years ago were included in this study. Fifty-six patients (M/F, 42/14; mean age, $59.2\pm9.2$ years) with LV wall motion abnormalities were compared to 77 patients (M/F, 50/27; mean age, $58.0\pm7.6$ years) without the wall motion abnormalities. Most patients (112/133, $84.2\%$) had undergone on-pump CABG with the in-situ left internal thoracic artery and free grafts of saphenous vein, in which the proximal and distal anastomoses were done for the single aortic cross-clamping period. Result: Ejection fraction of left ventricle was lower in the group with LV wall motion abnormalities (mean ejection fraction, $48.7\pm13.2\%$) compared to the group without wall motion abnormalities (mean ejection fraction, $57.1\pm10.1\%$)(p=0.0001). Risk­unadjusted survivals after CABG in the group without wall motion abnormalities were $85.7\pm4.0\%,\;76.2\pm4.9\%,\;and\;57.2\pm10.3\%$ at 5, 10, and 13 years, respectively, and in the group with wall motion abnormalities were $80.4\pm5.3\%,\;58.7\pm7.3\%,\;and\;51.9\pm7.9\%$ at 5, 10, and 13 years, respectively (p=0.1). In univariate analysis, predictable factors of long-term survival in the patients with LV wall motion abnormalities were LV ejection fraction and post operative outpatient treatment. In multivariate analysis, predictable factor of long-term survival in the patients with the wall motion abnormalities was postoperative outpatient treatment, and that in those without the wall motion abnormalities was female. Conclusion: Although there was no significant survival difference after CABG between the group with LV wall motion abnormalities and that without wall motion abnormalities, the survival in the group with wall motion abnormalities seems to be more decreased. For the patients with LV wall motion abnormalities after myocardial infarction, the post-CABG outpatient treatment is suggested to be an important factor for the long-term survival.

• Journal of Chest Surgery
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• 제35권1호
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• pp.1-10
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• 2002

Background: Despite the relatively high mortality rates in the chronic heart failure model induced by coronary artery ligation are relatively high, this model has been a subject of continuos research because of its clinical correlation. Chronic heart failure model of large-sized animals is very useful to analyse mechanical or biological effects on circulatory system which is difficult in small-sized animals. The purpose of this study is to establish the heart failure model by coronary artery ligation in sheep. Material and Method: Among 9 Corridale sheep, the homonymous artery and the diagonal branch were ligated simultaneously in 2 sheep and remaining 7 sheep were assigned to successive ligation of both arteries at an interval of 1 hour. Both coronary arteries were ligated from the point 40% proximal to the apex of the heart. Hemodynamic and echocardiographic parameters were analyzed before the ligation of the coronary artery, after the ligation of the homonymous artery, and after additional ligation of the diagonal branch. The experimental animals were sacrificed after 2 or 3 months of growth and histopathologic studies were performed Result: Immediate postoperative death occurred in the 2 sheep that had received simultaneous ligation of the homonymous artery and diagonal branch. On the other hand, all the 7 sheep that were lifated in succession were survived up to 3 months. Arterial pressure was sifnificantly decreased immediately after ligation of the homonymous artery(p<0.05), and the cardiac output was decreased and pulmonary capillary wedge pressure was increased after further ligation of the diagonal branch(p<0.05). Central venous pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, left ventricular end-diastolic dimension and end-systolic dimension were markedly increased 3 months after ligation of coronary arteries. Anteroseptal akinesia or dyskinesia was developed after the ligation of coronary arteries. Histopathologic study revealed we]1-demarcated ischemic area of fibrosis. Conclusion: Using methods of successive ligation of the homonymous artery and diagonal branch, chronic heart failure model could be reliably established in sheep.

• The Journal of the Korean bone and joint tumor society
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• 제10권1호
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• pp.1-12
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• 2004

Purpose: The current study was performed to analyze the oncological and functional results, and the patient, the limb and the prosthesis survival of osteosarcoma around the knee in children according to the treatment options. Materials and Methods: From 1982 to 2002, 63 patients with osteosarcoma around the knee underwent surgical treatments before 16 years of age. Surgical treatment options were amputation, endoprosthetic replacement, and implantation of low heat-treated autogenous bone graft after wide resection of tumor. The mean age of patients was 11.5 years (4.4~16), and the mean follow-up period was 6.1 years (2.1~16.8). All patients had neoadjuvant and adjuvant chemotherapy. All endoprosthses were extendible types. Anatomical locations of osteosarcoma were distal femur in 40 patients, and proximal tibia in 23 patients. As regard to Enneking stage, 4 patients had stage $II_A$, 50 patients had stage $II_B$, and 9 patients had stage III tumors. Results: The 5 year survival rate of stage $II_B$ patients was 72.7% in amputation, 83.7% in endoprosthesis, and 100% in low heat-treated autogenous bone graft. The 5 year survival rate of salvaged limb was 84.4% in endoprosthesis, and 80% in low heat-treated autogenous bone graft. The survival rate of prosthesis was 92.7% at 5 years, 67.4% at 10 years in endoprosthesis, and 75% at 5 years in low heat-treated autogenous bone graft. Mean functional outcome scores were 8.7 points in amputation, 20.6 points in endoprosthesis, and 16 points in low heat-treated autogenous bone graft. Distant metastasis occurred 15.8% in amputation, 27% in endoprosthesis and local recurrence occurred 8.1% in endoprosthesis, 14.3% in low heat-treated autogenous bone graft. Major complications happened 26.3% in amputation, 35.1% in endoprosthesis, and 28.6% in low heat-treated autogenous bone graft. Conclusion: Limb salvage procedure had functionally better results than amputation in children with osteosarcoma around the knee. Reconstruction with endoprosthesis after resection of tumor had good results in children as adults. In certain circumstances as too small bone for endoprosthesis or minimal bony destruction or too skeletally immature patient, low heat-treated autogenous bone graft may be a good treatment option. Low heat-treated autogenous bone graft may be considered as not only a substitute for endoprosthesis but also a temporary method before endoprosthesis.

• The Journal of the Korean bone and joint tumor society
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• 제9권1호
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• pp.84-92
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• 2003

Purpose: To report two cases of bone tumors other than osteoid osteoma in the proximal femur and treated with percutaneous high frequency radioablation method. Cases: We reviewed two cases with intracortical chondroma and enchondroma in the femoral head retrospectively. The patient with intracortical chondroma was a thirty one year old woman and had suffered right hip pain of 1 year duration. The lesion was located in the head of right femur and treated with CT guided percutaneous high frequency radioablation after needle biopsy under general anesthesia. The symptom was gone immediately after the procedure and was discharged postop. 1 day. 15 months has passed without symptom recurrence. Second case having enchondroma, was 56 year old woman complaining of gluteal area pain for 3 months. Radiologic evaluation showed osteolytic lesion with sclerotic rim on the inferior portion of the left femoral head. She received a same therapy with CT guided radiofrequency ablation following needle biopsy. She reported dramatic pain relief after the procedure and was discharged postop. 1 day. No symptom has occurred for 3 months until now. Conclusion: We present 2 cases of bone tumor occurred in the hip joint area other than osteoid osteoma which were treated with CT guided radiofrequency ablation.

• Journal of Yeungnam Medical Science
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• 제13권1호
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• pp.116-133
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• 1996

The biocompatibility of the titanium has been estabilished through various experimental studies such as cell culture toxicity test, pyrogen test, mutagen test and others. In order to confirm biocompatibility after fabrication of titanium and to clarify the difference between the bone reaction after insertion of the lathed titanium rods and the bone reaction after insertion of the finished and polished rods, both rods were implanted into the proximal femur of a rabbit. Histologic reactions in the bone were observed according to the ASTM standards at the intervals of 6 weeks, 12 weeks and 26 weeks after implantation. The result were as follows : In 6 weeks after implantation of lathed titanium rods, inflammatory reactions, such as minimal degree infiltration of polymorphonuclear leukocytes and lymphocytes were observed in all cases. This was thought to he caused by surgical trauma. However, inflammatory cell infiltration was not seen after implantation of polished and finished rods in all cases. The cellular infiltration and the histologic reaction of the hone after implantation of lathed group were significantly more pronounced than those after implantation of the finished group. In 12 weeks after implantation of lathed rods, two of four cases revealed a minimal degree of cellular infiltration. No inflammatory cell infiltration was demonstrated after implantation of the finished group. The cellular infiltration and histologic reaction seemed to be more pronounced in the lathed group, but they were not significant statistically. At 26 weeks after implantation of the lathed and finished group, there was no cellular infiltration in both groups. New bone formation was observed up 26 weeks, and no difference between lathed titanium rods and finished titanium rods were apparent. Mild bone necrosis was observed in 1 case out of 11 cases in which lathed titanium rods were implanted. Bone necrosis was not observed in the finished titanium rod group. Fibrosis was observed in both groups, but differences were not significant between the experimental groups. In the lathed titanium rods group and the shorter interval group, inflammatory cell infiltration was significantly higher. Finished titanium rods and longer interval groups had markedly decreased tendences in histologic reaction ratings. As a conclusion, although certificated titanium might be safe to use, difference of biocompatibility were observed depending on the method of surface finish. By identifying biocompatibility as a long-term standardized animal study, we can develop progressed internal fixation device that is safe for human beings.

• Journal of Gastric Cancer
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• 제8권1호
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• pp.27-34
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• 2008

Purpose: Many recent studies have reported on the feasibility and usefulness of laparoscopy assisted distal gastrectomy (LADG) for treating early gastric cancer. On the other hand, there has been few reports about laparoscopy assisted total gastrectomy (LATG) because upper located gastric cancer is relatively rare and the surgical technique is more difficult than that for LADG, We now present our procedure and results of performing LATG for the gastric cancer located in the upper or middle portion of the stomach. Materials and Methods: From Jan 2005 to Sep 2007, 96 patients underwent LATG by four surgeons at the Asan Medical Center, Seoul, Korea. Among them, 48 consecutive patients who were operated on by asingle surgeon were analyzed with respect to the clinicopathological features, the surgical results and the postoperative courses with using the prospectively collected laparoscopy surgery data. Results: There was no conversion to open surgery during LATG. For all the reconstructions, Roux-en Y esophago-jejunostomy and D1+beta lymphadenectomy were the standard procedures. The mean operation time was $212{\pm}67$ minutes. The mean total number of retrieved lymph nodes was $28.9{\pm}10.54$ (range: $12{\sim}64$) and all the patients had a clear proximal resection margin in their final pathologic reports. The mean time to passing gas, first oral feeding and discharge from the hospital was 2.98, 3.67 and 7.08 days, respectively. There were 5 surgical complications and 2 non-surgical complications for 5 (10.4%) patients, and there was no mortality. None of the patients needed operation because of complications and they recovered with conservative treatments. The mean operation time remained constant after 20 cases and so a learning curve was present. The morbidity rate was not different between the two periods, but the postoperative course was significantly better after the learning curve. Analysis of the factors contributing to the postoperative morbidity, with using logistic regression analysis, showed that the 8MI is the only contributing factor forpostoperative complications (P=0.029, HR=2.513, 95% CI=1.097-5.755). Conclusions: LATG with regional lymph node dissection for upper and middle early gastric cancer is considered to be a safe, feasible method that showed an excellent postoperative course and acceptable morbidity. BMI should be considered in the patient selection at the beginning period because of the impact of the BMI on the postoperative morbidity.

• Tuberculosis and Respiratory Diseases
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• 제47권5호
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• pp.669-680
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• 1999

Background: Pulmonary thromboembolism(PTE) is a life threatening disease that needs early diagnosis. Spiral CT angiography depict thromboemboli in the central pulmonary vessels with greater than 90% sensitivity and specificity, which approaches the results of pulmonary angiography in the Prospective Investigation of Pulmonary Embolism Diagnosis(PIOPED) study. This study was performed to evaluate the findings and the diagnostic value(clinical utility) of the spiral CT angiography with 2D image(multiplanar reformation) and 3D images(Shaded surface display, Minimal intensity projection) in the pulmonary thromboembolism. Methods: We retrospectively analysed spiral CT angiography and pulmonary angiography, lung scan and clinical recordings of 20 patients who had PTE diagnosed by spiral CT angiography(n=19 cases) or pulmonary angiography(n=l case) from September 1997 to August 1998. Among 20 patients who had underwent spiral CT angiography, 14 patients could be performed lung perfusion scan at the same time. We analyzed the vascular and parenchymal change in spiral CT angiogram. Results: Anatomical distribution of PTE was as follows: 1) left lung(n= 103)

• Journal of Gifted/Talented Education
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• 제11권3호
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• pp.131-153
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• 2001

The importance of identifying gifted children during early childhood is becoming recognized. Nonetheless, most researchers preferred to study the primary and secondary levels where children are already and more clearly demonstrating what talents they have, and where more reliable predictions of gifted may be made. Comparatively lisle work has been done in this area. When we identify giftedness during early childhood, we have to consider the potential of the young children rather than on actual achievement. Giftedness during early childhood is still developing and less stable than that of older children and this prevents us from making firm and accurate predictions based on children's actual achievement. Dynamic assessment, based on Vygotsky's concept of the zone of proximal development(ZPD), suggests a new idea in the way the gifted young children are identified. In light of dynamic assessment, for identifying the potential giftedness of young children. we need to involve measuring both unassisted and assisted performance. Dynamic assessment usually consists of a test-intervene-retest format that focuses attention on the improvement in child performance when an adult provides mediated assistance on how to master the testing task. The advantages of the dynamic assessment are as follows: First, the dynamic assessment approach can provide a useful means for assessing young gifted child who have not demonstrated high ability on traditional identification method. Second, the dynamic assessment approach can assess the learning process of young children. Third, the dynamic assessment can lead an individualized education by the early identification of young gifted children. Fourth, the dynamic assessment can be a more accurate predictor of potential by linking diagnosis and instruction. Thus, it can make us provide an educational treatment effectively for young gifted children.