• Journal of Chest Surgery
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• v.30 no.10
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• pp.949-960
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• 1997

Background. Limited ischemic tolerance of the lung has remained one of the factors that limits the expansion of pulmonary transplantation as a treatment for end-stage pulmonary disease. Numerous studies on safe long term preservation for lung transplantation has been performed for the purpose of developing ideal preservation solution with extracellular type or intracellular type solutions. In this. study, we examined the efficacy of L DG solution in lung preservation longer than 20 hours by comparison with modified Euro-Collins solution. Iwethods. Thirty-(our adult mongrel dogs were divided into two groups. Donor lungs were flushed with LPDG solution(n=9) or modified Euro-Collins(MEC) solution(n=8) and stored for 24 hours at 1$0^{\circ}C$. All donor lungs were perfused through the pulmonary arteries with solutions containing prostaglandin El and verapamil. Left canine lung allotransplantations wereperformed. Assessment(hemodynamic indices and arterial blood gas analysis) of left implanted lung was made by occluding the right pulmonary artery for ten minutes using pulmonary artery Cuff. Assessment was repeated at the interval of 30 minutes, one hour, and two hours later after reperfusion and then chest X-ray, computed tomogram and lung perfusion scan were obtained. In survival dogs follow-up studies were done with assessment with chest X-ray, computed tomogram of the chest and lung perfusion scan on 7th day postoperatively. After preservation above 20 hours, pathological examinations for ultrastructural findings on right lung were performed in each group. Results. With respect to arterial oxygen tension, LPDG group was superior to MEC but there was no statistical significance for 2 hours after reperfusion. Mean pulmonary artery pressure was less increased(p < 0.05) and cardiac output higher(p <0.05) than MEC group until 2 hours after reperfusion. After 2 hours of reperfusion, both groups showed transplanted lung function deteriorated gradually. Perfusion scan of the transplanted lung in LPDG group showed better perfusion rate in immediate post-reperfusion, 3 days and 7 days later respectively but there was no statistical significance and corelation with PaO2 and computed tomoRravhic views. In scanning electron microscopy of pulmonary artery after preservation, LPDG group relatively shows less irregular protrusion of the inner surface of endothelial cell of poulmonary artery than MEC group. Conclusions, e concluded that LPDG solution can offer safe lung preservation above 20 hours with adequate immunosuppressive therapy and prevention of the infection.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.169-175
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• 1998

Background: Heliox is known to decrease $PaCO_2$ in patients with increased airway resistance by increasing minute ventilation and reducing work of breathing(WOB). Besides these effect, heliox is expected to decrease functional anatomic dead space owing to improvement of peak expiratory flow rate(PEFR) and enhancement of gas distribution. We investigated whether heliox can decrease $PaCO_2$ even at the same minute ventilation (VE) and WOB with $N_2-O_2$ to speculate the effect of the heliox on the anatomic dead space. Material and Method: The subjects were 8 mechanically ventilated patients with asthma or upper airway obstruction(M : F=5 : 3, $68{\pm}10$years) who were under neuromuscular paralysis. The study was consisted of three 15-minutes phases: basal $N_2-O_2$ heliox and washout Heliox was administered via the low pressure inlet of servo 900C, and respiratory parameters were measured by pulmonary monitor(CP-100 pulmonary monitor, Bicore, Irvine, CA, USA). To obtain the same tidal volume(Vt) in heliox phase, the Vt on monitor was adjusted by the factor of relative flow rate of heliox to $N_2-O_2$. Dead space was calculated by Bohr equation. Results: 1) Vt, VE, peak inspiratory pressure(PIP) and peak inspiratory flow rate(PIFR) were not different between $N_2-O_2$ and heliox. 2) PEFR was higher on heliox($0.52{\pm}0.19$L/sec) than $N_2-O_2$($0.44{\pm}0.13$L/sec)(p=0.024). 3) $PaCO_2$(mmHg) were decreased with heliox($56.1{\pm}14.1$) compared to $N_2-O_2$($60.5{\pm}15.9$)(p=0.027). 4) Dead space ventilation(%) were decreased with heliox($73{\pm}9$ with $N_2-O_2$ and $71{\pm}10$ with heliox)(p=0.026). Conclusion: Heliox decreased $PaCO_2$ even at the same VE and WOB with $N_2-O_2$, and the effect was considered to be related with the reduction of anatomic dead space.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.57-66
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• 2007

Natural gases generally consist of mainly $^{12}C$ and about 1.1% of $^{13}C$. It is well known that a stable carbon isotope, $^{13}C$, has been widely used for the applications of medical, pharmaceutical, and agricultural tracers. As a result, the development of the separation and concentrating technology of $^{13}C$ can cause of high value-added products and the possibility of the generation of new carbon materials, In general, there are two kinds of approaches to obtain a stable $^{13}C$ isotope by the separation of cryogenic distillation. One is to obtain a concentrated $^{13}CH_4$ isotope from natural gas. Another approach is to get concentrated $^{13}CO$ by distillation followed by a chemical reaction of $CH_4$ and $H_2O$. In this study, rigorous process simulations of the cryogenic distillation have been performed and analyzed for the concentrated separation of $^{13}C$ isotopes from LNG and NG by using commercial process simulator. Due to the very small differences of relative volatilities and separabilities of $^{12}C$ and $^{13}C$, the process design and operation of effective separation and concentration of $^{13}C$ need special strategies and feasibility studies. Utilization of vapor pressure data to acentric factor in SRK equation of state and optimized process conditions have been able to predict for the effective of the separation yield and concentration of $^{13}C$ for the cryogenic distillation. The various operation strategies for both batch and continuous cryogenic distillation are also studied and suggested for the basic design of the process. Development of this study can provide a tool for the effective design and operation of the cryogenic separation of $^{13}C$.

• Tuberculosis and Respiratory Diseases
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• v.44 no.5
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• pp.1105-1113
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• 1997

Background : Prone position improves oxygenation in some patients with ARDS. According to some authors, prone position can also improve the deteriorated hemodynamics induced by PEEP. But these respiratory and hemodynamic effects of prone position has not yet been fully established. Methods : Twentythree consequtive patients with ARDS(M : F= 11 : 12, $62.1{\pm}20.8yrs$) were the subjects for this study. ABGA, static compliance of the respiratory system, mean arterial pressure and pulse rate were obtained in supine position and at 5min, 0.5h and 2h of prone position. Positive respiratory response was defined as 20mmHg or more increase in $PaO_2/FIO_2$ within 2h of prone position. Early of late respiratory responses were defined if the positive response was observed within of after 3 day of ARDS onset, respectively. Positive hemodynamic response was defined as 10mmHg or more increase in mean arterial pressure at 5min of prone position. Results : Fifteen patients (65%) showed positive respiratory response. In the respiratory responders, $PaO_2$ was $69.8{\pm}17.6mmHg$ in supine position, $83.2{\pm}22.6mmHg$ in prone position 0.5h, $96.8{\pm}22.7mmHg$ in prone position 2h(p<0.001), and $PaO_2/FIO_2$ was $108{\pm}41mmHg$, $137{\pm}57mmHg$, $158{\pm}50mmHg$, respectively(p=0.001). Age, sex, cause of ARDS, supine $PaO_2$ and $PaO_2/FIO_2$ were not different between the respiratory responders and the nonresponders. The respiratory responders, however, showed higher mean arterial pressure than the nonresponders($91.1{\pm}13.1mmHg$ vs. $76.0{\pm}18.7mmHg$, p=0.035), and tendency of higher survival rate(9/15 vs. 2/8, p=0.074). Static compliance of the respiratory system was decreased in prone position 0.5h($28.4{\pm}7.9ml/cm$ $H_2O$ vs. $23.8{\pm}7.6ml/cm$ $H_2O$, p=0.007). The overall rate of early response(n=23) and late response(n=11) were similar(14/23 vs. 7/11, p>0.05). But patient without early response showed late response only in 25%(1/4), while patient with early response showed late response in 85.7%(6/7)(p=0.072). Five patients(22%) showed positive hemodynamic response, two of them being respiratory nonresponders. There were no differences in the baseline mean arterial pressure or the level of PEEP applied in supine between the hemodynamic responders and the hemodynamic nonresponders. Conclusions : Prone position either improved oxygenation or increased arterial pressure in significant proportion of patients with ARDS. And the respiratory response to prone position was thought to be determined in the early stage of ARDS.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.140-152
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• 1998

Background: Prone position improves oxygenation in patients with ARDS probably by reducing shunt Reduction of shunt in prone position is thought to be effected by lowering of the critical opening pressure (COP) of the dorsal lung because the pleural pressure becomes less positive in prone position compared to supine position. It can then be assumed that prone position would bring about greater improvement in oxygenation when PEEP applied in supine position is just beneath COP than when PEEP is above COP. Hemodynamically, prone position is expected to attenuate the lifting of cardiac fossa induced by PEEP. Based on these backgrounds, we investigated whether the effect of prone position on oxygenation differs in magnitude according to the level of PEEP applied in supine position, and whether impaired cardiac output in supine position by PEEP can be restored in prone position. Methods: In seven mongrel dogs, $PaO_2/F_1O_2$(P/F) was measured in supine position and at prone position 30 min. Cardiac output (CO), stroke volume (SV), pulse rate (PR), and pulmonary artery occlusion pressure (PAOP) were measured in supine position, at prone position 5 min, and at prone position 30 min. After ARDS was established with warmed saline lavage(P/F ratio $134{\pm}72$ mm Hg), inflection point was measured by constant flow method($6.6{\pm}1.4cm$ $H_2O$), and the above variables were measured in supine and prone positions under the application of Low PEEP($5.0{\pm}1.2cm$ $H_2O$), and Optimal PEEP($9.0{\pm}1.2cm$ $H_2O$)(2 cm $H_2O$ below and above the inflection point, respectively) consecutively. Results : P/F ratio in supine position was $195{\pm}112$ mm Hg at Low PEEP and $466{\pm}63$ mm Hg at Optimal PEEP(p=0.003). Net increase of P/F ratio at prone position 30 min, however, was far greater at Low PEEP($205{\pm}90$ mm Hg) than at Optimal PEEP($33{\pm}33$ mm Hg)(p=0.009). Compared to CO in supine position at Optimal PEEP($2.4{\pm}0.5$ L/min), CO in prone improved to $3.4{\pm}0.6$ L/min at prone position 5 min (p=0.0180) and $3.6{\pm}0.7$ L/min at prone position 30 min (p=0.0180). Improvement in CO was attributable to the increase in SV: $14{\pm}2$ ml in supine position, $20{\pm}2$ ml at prone position 5 min (p=0.0180), and $21{\pm}2$ ml at prone position 30 min (p=0.0180), but not to change in PR or PAOP. When the dogs were turned to supine position again, MAP ($92{\pm}23$ mm Hg, p=0.009), CO ($2.4{\pm}0.5$ L/min, p=0.0277) and SV ($14{\pm}1$ ml, p=0.0277) were all decreased compared to prone position 30 min. Conclusion: Prone position in a dog with saline-lavaged acute lung injury appeared to augment the effect of relatively low PEEP on oxygenation, and also attenuate the adverse hemodynamic effect of relatively high PEEP. These findings suggest that a PEEP lower than Optimal PEEP can be adopted in prone position to achieve the goal of alveolar recruitment in ARDS avoiding the hemodynamic complications of a higher PEEP at the same time.

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.1-9
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• 1995

The slow development of histopathological changes and long period required for stabilization of lesions have suggested that secondary injury processes exacerbate the effect of initial mechanical insult after traumatic spinal cord injury (SCI). The importance of glutamate receptors in the normal functions of spinal cord, in concert with the large body of evidence that points to their involvement in neurotoxicity due to both ischemic and traumatic insults to the CNS, suggested a probable role of glutamate receptors in secondary injury process after traumatic SCI. In order to investigate the involvement of excitatory amino acid in the secondary injury process after SCI, this study examined the effect of dextrorphan, a noncompetitive NMDA receptor antagonist, on the recovery of hindlimb function and the residual tissue at injury site following SCI. Locomotor function was assessed using open field test (21 point scale). At 8 weeks spinal cord tissue was examined using quantitative histopathologic technique. Prior to surgery female Long-Evans rats were adapted to the test environment. Rats received laminectomies (T9/T10), and spinal cord contusions (NYU impactor) were produced by a 10 gm weight dropped 25 mm. DXT (15 or 30 mg/kg, i.p.) or saline was injected 15 min before contusion. Behavioral testing resumed 2 days post-injury and continued twice a week for 8 weeks. No differences between DXT and saline groups were found for hindlimb function and sparing tissue at the lesion site. These results suggest that NMDA receptor might not be involved in secondary injury processes after traumatic SCI.

• 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.38 no.1 s.246
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• pp.13-22
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• 2005

It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. Material and Method: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20$\~ $30 kg. Animals were randomly assigned to group 1 (n=6, non pulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system $(QFlow^{TM}-500)$ was inserted into the renal pa­renchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. Result: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5$\~$ 64 in group 1 vs. 65.8$\~$88.3 mL/min/100 g in group 2, p=0.026$\~$ 0.45) The difference was significant at 30 minutes bypass $(47.5{\pm}18.3\;in\;group\;1\;vs.\;83.4{\pm}28.5$ mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS). Conclusion: Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.441-447
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• 2023

Lead(Pb), which is currently mainly used for shielding purposes in the medical radiation, has excellent radiation shielding functions, but is continuously exposed to radiation directly or indirectly due to the harmfulness of lead itself to the human body and the inconvenience caused by its heavy weight. Research on shielding materials that are human-friendly, lightweight, and convenient to use that can block risks and replace lead is continuously being conducted. In this study, based on the commonly used polyethylene terephthalate (PET) film and the fabric material used in actual radiation protective clothing, a multi-layer thin film was realized through sputtering and vacuum deposition of bismuth, tungsten, and tin, which are metal materials that can shield radiation. Thus, a shielding film was produced and its applicability as a radiation shielding material was evaluated. The radiation shielding film was manufactured by establishing the optimized conditions for each shielding material while controlling the applied voltage, roll driving speed, and gas supply amount to manufacture the shielding film. The adhesion between the parent material and the shielding metal thin film was confirmed by Cross-cut 100/100, and the stability of the thin film was confirmed through a hot water test for 1 hour to measure the change of the thin film over time. The shielding performance of the finally realized shielding film was measured by the Korea association for radiation application (KARA), and the test conditions (inverse wide beam, tube voltage 50 kV, half layer 1.828 mmAl) were set to obtain an attenuation ratio of 16.4 (initial value 0.300 mGy/s, measured value 0.018 mGy/s) and damping ratio 4.31 (initial value 0.300 mGy/s, measured value 0.069 mGy/s) were obtained. by securing process efficiency for future commercialization, light and shielding films and fabrics were used to lay the foundation for the application of films to radiation protective clothing or construction materials with shielding functions.

• Korean journal of food and cookery science
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• v.26 no.5
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• pp.636-648
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• 2010

Two types of wild grape extracts(WGE) prepared by different methods were added into butter-top bread at different concentrations(0, 5, 10, 15, 20% of water). Then, the resulting breads were analyzed for their physicochemical and sensory properties in order to identify whether or not the WGE-enriched breads were comparable to control bread in terms of qualities and preferences. Wild grape sugar mixture(WGS), which was prepared by osmotic dehydration of wild grape fruits with the same amounts of sugar, presented significantly lower moisture content and titratable acidity as well as higher pH and sugar content compared to wild grape juice(WGJ), which was produced by boiling the fruits in a vacuum jar and squeezing. The pH of the doughs and breads containing WGE tended to decrease with increasing amounts of WGE, and this phenomenon was more appreciable in those containing WGJ than WGS. This was presumably due to the higher contents of tartaric acid in WGJ. For both types of extracts, hardness, gumminess, and chewiness of the doughs decreased with the addition of WGE, nevertheless, which properties were not remained in the resulting breads. This could be partially attributed to the relatively high degree of baking loss and lower pH of the WGE-enriched breads than those of control bread. Contrary to the mechanical analyses, the sensory properties of the breads were dependent on the WGE type. That is, WGJ-enriched bread showed lower consistency and moistness than control bread, which consequently led to relatively lower overall acceptability. However, WGS addition did not adversely affect the sensory properties of the bread. In particular, addition of 5% WGS somewhat improved the physical and sensory qualities of the bread. Thus, WGE-enriched bread could be produced without loss of bread quality when prepared with 5% WGS.