• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.292-297
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• 2022

Direct injection of CRISPR/Cas9 into zygotes enables the production of genetically modified nonhuman primates (NHPs) essential for modeling specific human diseases, such as Usher syndrome, and for developing novel therapeutic strategies. Usher syndrome is a rare genetic disease that causes loss of hearing, retinal degeneration, and problems with balance, and is attributed to a mutation in MYO7A, a gene that encodes an uncommon myosin motor protein expressed in the inner ear and retinal photoreceptors. To produce an Usher syndrome type 1B (USH1B) rhesus macaque model, we disrupted the MYO7A gene in developing zygotes. Identification of appropriately edited MYO7A embryos for knockout embryo transfer requires sequence analysis of material recovered from a trophectoderm (TE) cell biopsy. However, the TE biopsy procedure is labor intensive and could adversely impact embryo development. Recent studies have reported using cell-free DNA (cfDNA) from embryo culture media to detect aneuploid embryos in human in vitro fertilization (IVF) clinics. The cfDNA is released from the embryo during cell division or cell death, suggesting that cfDNA may be a viable resource for sequence analysis. Moreover, cfDNA collection is not invasive to the embryo and does not require special tools or expertise. We hypothesized that selection of appropriate edited embryos could be performed by analyzing cfDNA for MYO7A editing in embryo culture medium, and that this method would be advantageous for the subsequent generation of genetically modified NHPs. The purpose of this experiment is to determine whether cfDNA can be used to identify the target gene mutation of CRISPR/Cas9 injected embryos. In this study, we were able to obtain and utilize cfDNA to confirm the mutagenesis of MYO7A, but the method will require further optimization to obtain better accuracy before it can replace the TE biopsy approach.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.413-421
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• 1999

Background: Ischemia reperfusion injury is known to contribute to the major causes of the early graft failure in lung transplantation. Triiodothyronine (T3) has been suggested to ameliorate ischemia reperfusion injury from both in vivo and in vitro experiments of various organs. Prospecting its beneficial effect for pulmonary allograft preservation, we made a new solution by adding T3 into the extracellular type dextran solution. Material and Method: Twelve adult mongrel dogs underwent left lung allotransplantation. Six donor dogs were flushed with the new solution(Group 1, n=6), and the remaining six were flushed with Euro-Collins solution to serve as controls(Group 2, n=6). Allografts were stored in each preservation solution for 20 hours at 4$^{\circ}C$. Left single lung transplantations were performed. The right pulmonary artery and the right main bronchus were clamped at 15 minutes after the reperfusion and maintained throughout the experiment to evaluate the transplanted left lung function. Result: Arterial carbon dioxide tension was better in group 1 than in group 2 throughout the experiment period and the difference was statistically significant at 2 hours after reperfusion(28.0${\pm}$3.0 mmHg and 53.1${\pm}$17.4 mmHg, p<0.05). The differences of arterial oxygen partial pressure, peak airway pressure and pulmonary vascular resistance showed no statistical significance. The malondialdehyde(MDA) level, measured from tissue obtained at 120 minutes after reperfusion showed no statistically significant difference. The tissue wet/dry ratio of group 1(649${\pm}$27 %) was significantly lower than that of group 2(686${\pm}$71 %, p<0.05). The microscopic examination revealed varying degrees of injury represented mainly by findings such as perivascular neutrophil infiltration, capillary hemorrhage and interstitial congestion. These findings were less severe in group 1 than those in group 2. Conclusion: The new solution demonstrated superior allograft preservation after 20 hour ischemia compared to Euro-Collins solution in canine single left lung transplantation model, these results suggest that T3 might be a promising agent for pulmonary allograft preservation.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.1-10
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• 2004

Background: Currently, the cardiopulmonary machine with non-pulsatile pumps, which are low in internal circuit pressure and cause little damage to blood cells, is widely used. However, a great number of experimental studies shows that pulsatile perfusions are more useful than non-pulsatile counterparts in many areas, such as homodynamic, metabolism, organ functions, and micro-circulation. Yet, many concerns relating to pulsatile cardiopulmonary machines, such as high internal circuit pressure and blood cell damage, have long hindered the development of pulsatile cardiopulmonary machines. Against this backdrop, this study focuses on the safety and effectiveness of the pulsatile cardiopulmonary machines developed by a domestic research lab. Material and Method: The dual-pulsatile cardiopulmonary bypass experiment with total extracorporeal circulation was conducted on six calves, Extracorporeal circulation was provided between superior/inferior vena cava and aorta. The membrane oxygenator, which was placed between the left and right pumps, was used for blood oxygenation. Circulation took four hours. Arterial blood gas analysis and blood tests were also conducted. Plasma hemoglobin levels were calculated, while pulse pressure and internal circuit pressure were carefully observed. Measurement was taken five times; once before the operation of the cardiopulmonary bypass, and after its operation it was taken every hour for four hours. Result: Through the arterial blood gas analysis, PCO2 and pH remained within normal levels. PO2 in arterial blood showed enough oxygenation of over 100 mmHg. The level of plasma hemoglobin, which had total cardiopulmonary circulation, steadily increased to 15.87 $\pm$ 5.63 after four hours passed, but remained below 20 mg/㎗. There was no obvious abnormal findings in blood test. Systolic blood pressure which was at 97.5$\pm$5.7 mmHg during the pre-circulation contraction period, was maintained over 100 mmHg as time passed. Moreover, diastolic blood pressure was 72.2 $\pm$ 7.7 mmHg during the expansion period and well kept at the appropriate level with time passing by. Average blood pressure which was 83$\pm$9.2 mmHg before circulation, increased as time passed, while pump flow was maintained over 3.3 L/min. Blood pressure fluctuation during total extracorporeal circulation showed a similar level of arterial blood pressure of pre-circulation heart. Conclusion: In the experiment mentioned above, pulsatile cardiopulmonary machines using the doual-pulsatile structure provided effective pulsatile blood flow with little damage in blood cells, showing excellence in the aspects of hematology and hemodynamic. Therefore, it is expected that the pulsatile cardiopulmonary machine, if it becomes a standard cardiopulmonary machine in all heart operations, will provide stable blood flow to end-organs.

• Korean Journal of Health Education and Promotion
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• v.20 no.2
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• pp.35-61
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• 2003

Background： The purpose of this study was to develop a structured and individualized smoking prevention program for adolescents by utilizing a multimedia computer-assisted instruction model and to empirically assess its effect. Method： For the purpose of this study, a guide book of smoking prevention program for middle and high school students was developed as the first step. The contents of this book were summarized and developed into an actual multimedia CAI smoking prevention program according to the Gane ＆ Briggs instructional design and Keller's ARCS motivation design models as the second step. At the final step, the short-tenn effects of this program were examined by an experiment. This experiment were made for middle school and high school students and the quasi experimental design was the pretest - intervention - posttest. The measured data was attitude, belief, and knowledge about smoking, interest in the program, and learning motivation. Result： The results of this study were as follows： First, the guide book of a smoking prevention program was developed and the existing literature on adolescent smoking was analyzed to develop the content of the guide book. Then the curriculum was divided into three main domains on tobacco and smoking history, smoking and health, adolescent smoking and each main domain was divided into sub-domains. Second, the contents of the guide book were translated into a multimedia CAI program of smoking prevention througn Powerpoint software according to the instructional design theory. The characteristics of this program were interactive, learner controllable, and structured The program contents consisted of entrance(5.6％), history of tobacco(30％), smoking and health(38.9％), adolescent smoking(22.2％), video(4.7％), and exit(1.6％). Multimedia materials consisted of text(121), sound and music, image(still 84, dynamic 32), and videogram(6). The program took about 40 minutes to complete. Third, the results on analysis of the program effects were as follows： 1) There was significant knowledge increase between the pre-test and post-test with total mean difference 3.44, and the highest increase was in the 1st grade students of high school(p＜0.001). 2) There was significant decrease in general belief on smoking between the pre-test and post-test with total mean difference 0.28. In subgroup analysis, the difference was significantly higher in the 1st grade of high school (p<0.001), low income class (p<0.001), and daily smokers (p<0.01). 3) There was no significant difference in attitudes on his personal smoking between the pre-test and post-test. 4) The interest in the program seemed to lower as students got older. The score of motivation toward this prevention program was the highest in the middle school 3rd grade. Among sub-domains of motivation, the confidence score was the highest. Conclusion： To be most effective, the smoking prevention program for adolescents should utilize the most up-to-date and accurate information on smoking, and then instructional material should be developed so that the learners can approach the program with enjoyment. Through this study, a guide book with the most up-to-date information was developed and the multimedia CAI smoking prevention program was also developed based on the guide book. The program showed positive effect on the students' knowledge and belief in smoking.

• Journal of Chest Surgery
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• v.36 no.12
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• pp.894-903
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• 2003

Protection against ischemia-reperfusion injury is crucial for successful transplantation of the lung. It has been known that nitric oxide has many favorable effects on the donor lungs but at the same time, has some potential side effects of cytotoxicity. In this regards, we investigated whether the administration of nitroglycerin could decrease ischemia-reperfusion injury in isolated rat lung reperfusion model for the confirmation of the effect of nitroglycerin, a donor of nitric oxide, on lung transplantation. Material and Method: 35 Sprague-Dawley species male white rats were used for this experiment. For nitroglycerin group (n=18), nitroglycerin was administered intravenously followed by mixed in flushing solution for preservation. As a control group (n=17), we used the same amount of normal saline. To evaluate the effect of nitroglycerin on the lung, heart-lung block was obtained, weighed and stored in University of Wisconsin Solution at 1$0^{\circ}C$ for 24 hours. In each group of the isolated lungs, reperfusion was carried out with Krebs-Hensleit-diluted human blood for 60 minutes. As parameters of the state of the isolated lung, peak inspiratory and pulmonary arterial pressures were continuously recorded. Oxygen and carbon dioxide tension of reperfusing blood were measured before and after 30, 60 minutes of reperfusion. After sixty minutes of reperfusion, protein content in bronchoalveolar lavage fluid was measured also for the evaluation of the degree of alveolar flooding. Lung myeloperoxidase activity was determined to verify the accumulation of neutrophils. Results: Although statistically significant differences were not noted in peak inspiratory and pulmonary arterial pressure between control and nitroglycerin group, latter group showed lowering tendency of pulmonary arterial pressure during the entire reperfusion period. Oxygen tension was higher (p<0.05) in nitroglycerin group compared with that of the control group, in contrast, there were no differences in carbon dioxide tension, protein content in bronchoalveolar lavage fluid and myeloperoxidase activity between the groups. In the examination of ultrastructural changes, nitroglycerin denoted the protective effect on the pulmonary architecture compared with that of control group. Conclusion: Collectively, on the bases of these experimental results, prior treatment of donor lung with nitroglycerin could result in better preservation of the lung. Consequently, these nitroglycerin preserved lungs are thought to be more suitable for successful transplantation of the lung.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.180-192
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• 2007

Background: As determined from the recent investigations of discordant cardiac xenotransplantation, hyperacute rejection occurs mainly at the endothelial cells in donor microvascular systems, but this does not occur at cardiac valve leaflets or at medium-to-large caliber vessels. On the basis of this background, this study was performed to look into the biocompatibility for transplantation of a middle or large diameter xenogenic blood vessel by conducting xenogenic arterial transplantation with the carotid artery in a pig-to-goat model. Material and Method: The experimental group was composed of 10 pairs of pig-to-goat combinations. They were divided into each period of 1 week, and 1, 3, 6 and 12 months. Four carotid artery grafts obtained through collection of the bilateral carotid arteries from two pigs were preserved at $-70^{\circ}C$ without other treatment, and then they were transplanted into the bilateral carotid arteries of two goats. Doppler ultrasonography was done on a periodic basis after transplantation to evaluate the patency of the grafted blood vessel. At the ends of a predetermined period, the grafts were explanted from the goats and they underwent gross examination. Hematoxylin-eosin and Masson's trichrome staining were conducted. In addition, in order to examine the immunological rejection of the grafted xenogenic blood vessel, immunohistochemical staining was conducted with T-lymphocyte indicator and von Willebrand factor. Result: Two goats at the each one-week period and the one-year period died during the experimental period because of a reason unrelated to the experimental procedure, and the remaining 8 goats survived until the end of each experiment period. On Doppler ultrasonography, unilateral carotid artery occlusion was found in a goat, whose period was specified as 3 months, among the 8 survived goats. However, the vascular patency was maintained well and there was no graft that formed aneurysms in the other goats. On gross examination, the region of vascular anastomosis was preserved well, and calcification of the grafted blood vessel was not shown. Histologically, the endothelial cells of the graft disappeared one week after transplantation, and then there was progressive spread of the recipients' endothelial cells from the anastomotic site. The reendothelialization occurred over the whole graft at one month after transplantation. The neointimal thickening and adventitial inflammation became severe by 3 months after transplantation, but this lessened at 6 months and 12 months, respectively. The rate of CD3 positive cells was very low among the infiltrated inflammatory cells. Conclusion: The fresh-frozen xenogenic artery kept its patency without being greatly influenced by xenogenic immune reaction.

• Progress in Medical Physics
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• v.15 no.4
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• pp.202-209
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• 2004

Flat panel based digital radiography (DR) systems have recently become useful and important in the field of diagnostic radiology. For DRs with amorphous silicon photosensors, CsI(TI) is normally used as the scintillator, which produces visible light corresponding to the absorbed radiation energy. The visible light photons are converted into electric signal in the amorphous silicon photodiodes which constitute a two dimensional array. In order to produce good quality images, detailed behaviors of DR detectors to radiation must be studied. The relationship between air exposure and the DR outputs has been investigated in many studies. But this relationship was investigated under the condition of the fixed tube voltage. In this study, we investigated the relationship between the DR outputs and X-ray in terms of the absorbed energy in the detector rather than the air exposure using SPEC-l8, an X-ray energy spectrum model. Measured exposure was compared with calculated exposure for obtaining the inherent filtration that is a important input variable of SPEC-l8. The absorbed energy in the detector was calculated using algorithm of calculating the absorbed energy in the material and pixel values of real images under various conditions was obtained. The characteristic curve was obtained using the relationship of two parameter and the results were verified using phantoms made of water and aluminum. The pixel values of the phantom image were estimated and compared with the characteristic curve under various conditions. It was found that the relationship between the DR outputs and the absorbed energy in the detector was almost linear. In a experiment using the phantoms, the estimated pixel values agreed with the characteristic curve, although the effect of scattered photons introduced some errors. However, effect of a scattered X-ray must be studied because it was not included in the calculation algorithm. The result of this study can provide useful information about a pre-processing of digital radiography.

• Journal of Chest Surgery
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• v.32 no.3
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• pp.215-223
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• 1999

Background: The replacement of the narrowed long-segment trachea with various prosthetic materials or tissue grafts remains a difficult and unsolved surgical problem. Homologous cryopreserved tracheal transplantation has been considered to treat the irreversibly-damaged organs, such as in the lung or heart transplantation and also to overcome the limited supply of donor organs. We examined the morphological changes and the immunosuppressive effects of the cryopreserved trachea after the heterotopic transplantation in the rats. Material and Method: Sixty tracheal segments harvested from 30 donor Wistar rats were heterotopically implanted into the peritoneal cavity of 20 recipient Wistar rats and 40 Sprague Dawley rats. The 60 recipient rats were divided into 6 groups(10 rats/ group). In groups I, II, and III, 30 tracheal segments were implanted immediately after the harvesting and in groups IV, V, and VI, the segments were implanted 28 days after the cryopreservation. Groups I and IV were Wistar syngeneic controls. Groups II and V were Sprague Dawley recipients receiving no immunosuppression and Groups III and VI, were Sprague Dawley recipients receiving immunosuppressive agents. At 28 days all rats were sacrificed and the tracheal segments were evaluated grossly and histologically. Result: Immunosuppression of the tracheal segments had a significant influence on the changes of the tracheal lumen and tracheal epithelial cells, irrespective of the cryopreservation of the trachea(p<0.001). In groups III and VI receiving immunosuppressive agents, the tracheal lumen was patent and the normal epithelial cells were observed, however in the other groups not receiving the immunosuppressive agents, there were almost luminal obliteration by the proliferation of the fibrous tissues and a loss of the epithelial cells, the findings were similar to those in the case of obliterative bronchiolitis after a lung and a heart-lung transplantation. Conclusion: With the appropriate immunosuppressive agents, the lumen and the respiratory epithelium of the transplanted tracheal segment were well preserved, even after the cryopreservation of the tracheal segment, which shows the possibility of the long-term preservation and homologous transplantation of the trachea. But fibroproliferative obliteration of the tracheal lumen and the loss of the normal respiratory epithelial cells, characteristic findings of obliterative bronchiolitis, were observed in the groups without the immunosuppression. This experiment using the rat trachea may be useful in studying the pathogenesis, treatment, and prevention of obliterative bronchiolitis after a lung and a heart-lung transplantation.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.7-24
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• 1977

This paper is the forth and fifth one of the study on balanced type oscillating mole drainer. In the light of the results from previous reports about the model tests, some design criteria were established and a prototype machine was set up for experimental purpose. Motion characteristics and functionof the each parts of the machine were checked and analyzed. After that, performance tests of the prototype machine were carried out in thefield. Obtained results are summarized as follows ; 1. Ten centimeter of the bullet diameter was determined so as to be able to attach it to the tractors with capacity of 30 PS to 40 PS. 2. To maintain the balance between the moments of the front shank and rear shank, the oscillating amplitude of the rear bullet was determined to be larger than that of the front bullet. At the same time , the oscillating direction of the rear bullet was designed with the inclines of ten to thirty degrees. 3. An octagonal dynamo transduced was developed for measuring the compressive force of the upper link is measuring the draft force of the machine. Acceptable linear relationship between forces and strain responses from O.D.T. was obtained. 4. Analysing the balancing mechanism of the acting part of the machine , it was found that the total draft force of the machine was equal to the difference between the sum of the draft force produced from the right and left side bending moments of the lower drawber and the compressive force on the upper link. 5. There are acceptable linear relationship between the strain and twisting moment by driving shaft, and between strain and shank moment. Above results enable us to carry out the field experiment with prototype machine. 6. When the test machine was used in the field, it was possible to reduce the oscillating acceleration by forty percent in average as compared it with the single bullet mole drainer. 7. When the test machine was used under the oscillating condition, the dratt torce was reduced by 27 percent to 59 percent as compared it with the test machine under non-oscillating condition, while the draft force was increased by 7 percent to 20 percent as compared it with the mole drainer having oscillating single bullet. The reasoning behind this fact was considered as the resistance force due to the rear shank and bullet. 8. As the amplitude and frequency of the bullet were increased, the torque was increased accordingly. This tendency could be varied with the various characteristics of the given soils. And the larger frequency and amplitute, the more increasing oscil\ulcornerlating power but decreasing draft brce were needed, and draft force was increased as the velocity was increased.9. When the amplitude of the rear bullet was designed to be larger than that of the front bullet, the minimum value of the moment was lowered and oscillating acceleration was reduced. And when the oscillating direction of the rear bullet was declined back\ulcornerwards, oscillating acceleration was increased along with the increasing angle of decli\ulcornernation. When the test machine was operated in high speed, the difference between maximum moments and minimum ones became narrow. This varying magnitude of moments appeared on the moment oscillogram seems to be correlated to the oscillating acceleration and draft force. 10. From the analysis of variance, it was found that those factors such as frequency, amplitude, and operating velocity significantly affected in the oscillating acceleration, the draft resistance, the torque, the moment, and the total power required. And interaction between frequency and amplitude affected in the oscillating acceleration. 11. Within the given situation of this study, the most preferable operating conditions of the test machine were 7 Hz in oscillating frequency, 0.54 m/sec in operating velocity, and 39.1 mm in oscillating amplitude of front and rear bullets. However, it is necessary to select the proper frequency and magnitude of oscillation depending on the soil properties of the field in which the mole drainer is practiced by use of a bal1nced type oscillating mole drainer. 12. It is recommended that a comparative study of the mole drainers would be performed in the near future using two separate balanced oscillating bullet with the one which is operated by oscillating the movable bullet in a single cylinder or other balanced type which may be single oscillating bullet with spring, damper or balancing weight, and that of thing. To expand the applicability of the balanced type oscillating mole drainer in practical use, it is suggested to develop a new mechanism which perform mole drain with vinyl pipe or filling material such as rice hull.

• Journal of Chest Surgery
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• v.32 no.7
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• pp.637-647
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• 1999

Background: Ischemia-reperfusion injury is one of the major contributing causes of early graft failure in lung transplantation. It has been suggested that triiodothyronine (T3) may ameliorate ischemia-reperfusion injury to various organs in vivo and in vitro. Predicting its beneficial effect for ischemic lung injury, we set out to demonstrate it by administering T3 into the in situ canine ischemia-reperfusion model. Material and Method: Sixteen adult mongrel dogs were randomly allocated into group A and B. T3 $(3.6\mug/kg)$ was administered before the initiation of single lung ischemia in group B, whereas the same amount of saline was administered in group A. Ischemia was induced in the left lung by clamping the left hilum for 100 minutes. After reperfusion, various hemodynamic parameters and blood gases were analyzed for 4 hours while intermittently clamping the right hilum in order to allow observation of the injured left lung function. Result: Arterial oxygen partial pressure $(PaO_2)$ decreased 30 minutes after reperfusion and recovered gradually thereafter in both groups. In group B the decrease of $PaO_2$ was less marked than in group A. The recovery of $PaO_2$ was faster in group B than in group A. The differences between the two groups were statistically significant from 30 minutes after reperfusion $(125\pm34$ mmHg and $252\pm44$ mmHg, p<0.05) until the end of the experiment $(178\pm42$mmHg and $330\pm37$ mmHg, p<0.05). The differences in the arterial carbon dioxide pressure, airway pressure and lung compliance showed no statistical significance. The malondialdehyde (MDA) level, measured from the tissue obtained 240 minutes after reperfusion, was lower in group B $(0.40\pm0.04\mu$M) than in group A $(0.53\pm0.05\mu$M, p<0.05). The ATP level of group B $(0.69\pm0.07\mu$M/g) was significantly higher than that of group A $(0.48\pm0.07\mu$M/g, p<0.05). The microscopic exami nation revealed varying degrees of injury such as perivascular neutrophil infiltration, capillary hemorrhage and interstitial congestion. There were no differences in the microscopic findings between the two groups. CONCLUSION T3 has beneficial effects on the ischemic canine lung injury including preservation of oxygenation capacity, less production of lipid peroxidation products and a higher level of tissue ATP. These results suggest that T3 is effective in pulmonary allograft preservation.