• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.846-855
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• 1999

Background : Secondary pulmonary hypertension is an important final endpoint in patients with chronic hypoxic lung disease, accompanied by deterioration of pulmonary hemodynamics. The clinical diagnosis of pulmonary hypertension and/or cor pulmonale could be difficult, and simple noninvasive evaluation of pulmonary artery pressures has been an relevant clinical challenge for many years. Doppler echocardiography might to be a more reliable method for evaluating pulmonary hemodynamics in such patients in terms of the accuracy, reproducibility and easiness for obtaining an appropriate echocardiographic window than M-mode echocardiography. The aim of this study was to assess echocardiographic parameters associated with pulmonary arterial hypertension, defined by increasing right ventricular systolic pressure(RVSP), calculated from trans-tricuspid gradient in patients with chronic hypoxic lungs. Method : We examined 19 patients with chronic hypoxic lung disease, suspected pulmonary hypertension under the clinical guidelines by two dimensional echocardiography via the left parasternal and subcostal approach in a supine position. Doppler echocardiography measured RVSP from tricuspid regurgitant velocity in continuous wave with 2.5MHz transducer and acceleration time(AT) on right ventricular outflow tract in pulsed wave for the estimation of pulmonary arterial pressure. Results : On echocardiography, moderate to severe degree of pulmonary arterial hypertension was defined as RVSP more than 40mmHg, presenting tricuspid regurgitation. Increased right ventricular endsystolic diameter and shortened AT were noted in the increased RVSP group. Increased RVSP was correlated negatively with the shortening of AT. Other clinical data, including pulmonary functional parameters, arterial blood gas analysis and M mode echocardiographic parameters were not changed significantly with the increased RVSP. Conclusion : These findings suggest that shortened AT on pulsed doppler can be useful when quantifying pulmonary arterial pressure with increased RVSP in patients with chronic lung disease with hypoxemia. Doppler echocardiography in pulmonary hypertension of chronic hypoxic lungs is an useful option, based on noninvasiveness under routine clinical practice.

• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.775-785
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• 1999

Background : The herbicide paraquat can cause severe lung injury and fibrosis in experimental animals. In this study we have investigated the changes in lung endothelin-1(Et-1) levels and immunohistochemical localization in relation to treatment with cyclophosphamide and methylprednisolone in paraquat induced pulmonary fibrosis in guinea pigs. Material and methods : 29 male Hartley guinea pigs were divided into 4 groups. Group I was normal control. Paraquat was instilled into the lung of guinea pig of group II, III and IV unilaterally. Group II was treated with cyclophosphamide and methylprednisolone. Group III was treated with methlprednisolone. Group IV was not treated. The degree of fibrosis was evaluated by H-E stains and Masson's trichrome stains and cell activity was assessed by Et-1 immunohistochemical stains. Statistical evaluation was performed using the Kruskawallis oneway analysis. Results : Paraquat induced an increase in numbers of fibroblasts and total amount of lung collagen in Group IV compared to the normal controls. There was no significant difference in total numbers of fibroblasts between any of paraquat instilled groups, but there was significant increase in total amount of collagen in Group IV compared to group II and III (p<0.05). The treatment of cyclophosphamide and methyprednisolone suppressed the growths of both fibroblasts and collagen, but this suppression was stastically significant only in the case of collagen Et-1 immunoreactivities of bronchial epithelium, type II pneumocytes, endothelial cells and fibroblast in group II and III were decreased compared to those in group IV. Conclusion : These results demonstrate that Et-1 is an important contributing factor in the pathogenesis of pulmonary fibrosis. Et-1 is synthesized and released by bronchial epithelium, Type II pneumocyte, endothelial cells, alveolar macrophages and fibroblasts. Especially they are associated with alveolar macrophage and fibroblasts. We conclude that combined therapy of cyclophosphamide and methylprednisolone are more effective in the control of Et-1 expression and collagen deposition.

• Tuberculosis and Respiratory Diseases
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• v.50 no.4
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• pp.462-472
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• 2001

Background : The determinants of intubation and the response to therapy in COPD patients with hypercapnic respiratory failure were retrospectively reviewed. Methods : This study involved a review of 132 episodes of hypercapnic respiratory failure($PaCO_2\;{\geq}\;50\;mmHg$ and $pH\;{\leq}\;7.35$). The time frame for resolution or the time to intubation of patients who were admitted between 1996 and 1999 was analyzed. Results : Out of 132 hypercapnic episodes, 49(37%) required intubation. A comparison was made with the 83 cases that responded to treatment. Patients requiring intubation had a greater severity of illness, which included a higher APACHE II (Acute Physiology and Chronic Health Evaluation II) score ($20{\pm}5$ vs $14{\pm}4$ ; p<0.01), a higher WBC, a higher serum BUN, and greater acidosis (pH, $7.23{\pm}0.11$ vs $7.32{\pm}0.04$ ; p<0.01). Those with the most severe acidosis(pH<7.20) had the highest intubation rate(87%) and shortest time to intubation($2{\pm}3\;h$). Conversely, those with an initial pH 7.31 to 7.35 were less likely to be intubated(20%), and had a longer time to intubation($97{\pm}121\;h$). The patients with a pH 7.21 to 7.25($4.1{\pm}2.9$ day) required longer period of time to respond to medical treatment than patients with a pH of 7.31 to 7.35($2.2{\pm}3.1$ day). Of those patients requiring intubation, half(55%) were intubated within 8 h of admission, and most (75%) within 24 h. Of those patients responding to treatment medical therapy, half(52%) recovered within 24 h and most (78%) recovered within 48 h. Conclusion: Respiratory acidosis at the initial presentation is associated with an increased likelihood of intubation. This should assist in deciding help with the decision whether to treat patients medically, institute noninvasive ventilation, or proceed to intubation.

• Tuberculosis and Respiratory Diseases
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• v.48 no.3
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• pp.315-323
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• 2000

Background : An immunochromatographic assay (ICT Diagnostics) which facilitates the diagnosis of tuberculosis(TB) by detecting serum antibodies mainly directed against specific 38KDa of Mycobacterium tuberculosis has come into the market. The test consists of a cardboard folding device containing nitrocellulose strip and absorbent pads. The whole procedure is completed within 15 min and does not require any additional equipment. The test has been reported to be sensitive and specific in diagnosing active TB. Thus the test had been evaluated with sera from TB patients and TB-free subjects. Method : Sera from patients with active pulmonary tuberculosis(40 sputum positives for Mycobacterium tuberculosis, 79 sputum negatives, and 3 extrapulmonary tuberculosis) were obtained from the Double-Cross Chest Clinic of the Korean National Tuberculosis Association (KNTA) in Seoul. The control group consisted of TB-free 68 subjects(21 children under 7 years old and 47 healthy staff members of KNTA). Results : Nine out of 68(13.2%) TB-free controls had positive antibody response. Total 106 of 122(86.9%) radiologically active patients had positive antibodies while 16 (13.1%) showed negative reaction. Antibody was detected in 38 of 40(95.0%) sputum positive patients and 68 of 82(82.9%) sputum negative patients who were under the antituberculosis chemotherapy. The sensitivity and specificity were all 87% and the positive predictive value was 92.2% while the negative predictive value was 78.7%, when the prevalence of TB in the sample was 64.2%. Our results clearly show that the detection of antibodies which mainly react with the 38KDa antigen of M. tuberculosis is not suitable as the first-line method of diagnosis but considered only as an adjunctive test to standard techniques of tuberculosis diagnosis. when considering its high false positivity.

• Tuberculosis and Respiratory Diseases
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• v.54 no.4
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• pp.429-438
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• 2003

Background : The mortality from acute respiratory distress syndrome(ARDS) is >40-50%. Although some prospective trials have failed to demonstrate a survival benefit of steroids in the early stages of ARDS, there are some reports showing some success with steroids in the later stages. This study observed the changes in the physiologic parameters with time in late ARDS patients who were treated with steroids. Methods : The medical charts of 28 intensive care unit patients(male:female=24:4; mean age 64 years), who had been diagnosed with refractory late ARDS ($PaO_2/FIO_2$ <200) and were treated with corticosteroids from December 1999 to July 2002, were retrospectively reviewed. The patients were divided into two groups: the weaned group(n=14), which included the patients who had been successfully weaned from a ventilator after corticosteroid therapy, and the failed group(n=14), which included the patients who had failed weaning. The physiologic parameters included the $PaO_2/FIO_2$ ratio, the positive end-expiratory pressure(PEEP) level, the $PaCO_2$, compliance, the sequential organ failure assessment(SOFA) score, the acute physiologic and the chronic health evaluation(APACHE) II score, and the Murray Lung Injury Score(LIS) in the two groups were compared from the day of mechanical ventilation(Dmv) to 7 days after the corticosteroid therapy. Results : There was no significant difference in the clinical characteristics and the physiologic parameters between the two groups prior to the corticosteroid therapy except for the SOFA score at Dmv(weaned group : $6.6{\pm}2.5$ vs failed group : $8.8{\pm}2.9$, p=0.047). However, within 7 days after corticosteroid therapy, there was significant improvement in the $PaO_2/FIO_2$ ratio, the PEEP level, the $PaCO_2$, the SOFA score, the APACHE II score, and the LIS of the weaned group compared to the failed group. Conclusions : During corticosteroid therapy in late ARDS, the continuation of corticosteroid therapy should be determined carefully in patients who do not show improvement in their physiologic parameters by day 7.

• Tuberculosis and Respiratory Diseases
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• v.59 no.5
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• pp.487-496
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• 2005

Background : 'Major pulmonary thromboembolism' is defined as right ventricular (RV) dysfunction, with or without shock, accompanied by significant morbidity and mortality. In this study, those with major pulmonary thromboembolism were divided into the shock and RV dysfunction only groups, and then investigated the mortality and complications in thrombolysis or anticoagulation, respectively. Methods : In a retrospective study, between January 1995 and December 2004, 60 eligible patients with a major pulmonary thromboembolism, admitted in Asan Medical Center, were included. Results : A total of 57 patients were treated with medical therapy. Thrombolysis was performed in 13 patients (23%) and anticoagulation in 44 (77%). There were no differences in the APACHEII and SOFA scores between the two groups. 6 (46%) and 11 (25%) patients died in the thrombolysis and anticoagulation groups, respectively (p=0.176). In the 19 patients (33%) showing shock, thrombolysis was performed in 9 (47%) and anticoagulation in 10 (53%). 4 (44%) of the 9 patients treated with thrombolytic agents and 3 (30%) of the 10 treated with anticoagulants died (p=0.650). In the 38 patients (67%) showing RV dysfunction only, thrombolysis was performed in 4 (11%) and anticoagulation in 34 (89%). 2 (50%) of the 4 patients treated with thrombolytics and 8 (24%) of the 34 treated with anticoagulants died (p=0.279). Three patients (23%) who underwent thrombolysis had a major bleeding episode, compared with 2 (5%) who were treated with anticoagulants (p=0.072). Conclusion: The results of our study showed that thrombolysis did not lower mortality and tended to increase major bleeding compared with anticoagulation in both the shock and RV dysfunction only groups. Further evaluation of the efficacy and safety of thrombolytic therapy for major thromboembolism appears warranted in Korea.

• Tuberculosis and Respiratory Diseases
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• v.64 no.6
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• pp.445-450
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• 2008

Background: As the number of older-aged people increases, the number of elderly patients who receive critical care services is expected to increase substantially. The objective of this study was to examine the clinical characteristics and outcomes of elderly patients who receive mechanical ventilation for more than 30 days in the medical intensive care unit (MICU) at a university hospital. Methods: We retrospectively examined forty-one elderly patients (${\geq}65$ years old) who were receiving mechanical ventilation, from April 2004 to March 2007, for periods exceeding 30 days at the MICU at Eulji University Hospital. Results: The MICU and hospitalmortality rate were 60.9% and 65.9%, respectively. The mean length of the ICU stay was 57.5 days and the mean duration of mechanical ventilation was 49.3 days. The most common reason for MICU admission was acute respiratory failure (73.2%), followed by sepsis (12.2%), neurological problems (9.8%), and gastrointestinal bleeding (4.9%). The Acute Physiology and Chronic Health Evaluation (APACHE) II scores were higher for the nonsurvivors than for the survivors (28.0 vs. 25.0, respectively, p=0.03). The nonsurvivors received more red blood cell (RBC) transfusions during their ICU stay than did the survivors (84.0% vs. 43.8%, respectively p=0.007). The factors associated with hospital death were the APACHE II score and if the patient had received a RBC transfusion. Conclusion: The APACHE II score and a RBC transfusion were predictors of increased hospital mortality for the elderly patients who were on prolonged mechanical ventilation. These predictors may assist physicians to make clinical decisions for this patient population.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.769-777
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• 2002

Using four components - nonionic surfactants, water, hydrocarbon oil and an alcohol as cosurfactant, 12 types of cleaning agents were prepared, and their physical properties such as surface tension, viscosity, electroconductivity and phase stability were measured. As the formulated cleaning agents have low surface tensions(30.5-31.1 dyne/cm) and low viscosities (1.6-7.2 c.p.), they are satisfied with the general physical properties of water-in-oil(W/O) microemulsions for their industrial use. They showed a tendency that their temperature range for stable one-phase microemulsion decreased in accordance with the increase of alcohol/surfactant(A/S) ratio in the formulations. However, the temperature range of one-phase microemulsion was much more affected by hydrophilic lipophillic balance(HLB) value of the nonionic surfactant which increased its temperature range and it increased in accordance with the higher HLB value in the formulations. And the maximum content of water which can keep stable one-phase W/O microemulsion was measured at each sample. In addition, their temperature range for stable one-phase microemulsion was also measured. It was confirmed that the selection of surfactant type was very important for formulating a cleaning agent, since the W/O microemulsion system with the nonionic surfactant of the lower HLB value showed better cleaning efficacy that of the higher HLB value for abietic acid as a soil, which was used for preparing a rosin-type flux. In the formulated cleaning agents with the increase of A/S ratio in the formulations, however, there was no significant difference in cleaning efficacy. It was investigated that the differences of their cleaning efficacy was affected by the change of the condition of temperature and sonicating frequency as important factors in the industrial cleaning. That is, the higher, their cleaning temperature and the lower, their sonicating frequency, the more increased, their cleaning efficacy. Furthermore, using optical instruments like UV/Visable Spectrophotometer and FT-IR Spectrometer, their cleaning efficacy for abietic acid was measured. The removal of soil from the contaminated rinse water was measured by gravity separation method in the rinse bath. As a result, the cleaning agent system having the nonionic surfactant of HLB value 6.4 showed over 85% water-oil separation efficacy at over $25^{\circ}C$. Therefore, it was demonstrated in this work that the formulating cleaning agents were very effective for cleaning and economical in the possible introduction of water recycling system.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.84-91
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• 2020

The efficiency of the synthetic magnesium silicate used in basic polyols and edible oil purification is evaluated by its purification ability and filtration rate and is affected by the particle size and surface area of magnesium silicate. In this study, it was investigated the change on the particle size of magnesium silicate was influenced by the reaction temperature, injection rate, injection order (Si, Mg) and Mg/Si reaction mole ratio. The synthesized magnesium silicate was compared and analyzed for the synthesis, grinding, and refining processes. In the synthesis process, the reaction temperature and feed rate did not affect the average particle size change of magnesium silicate, while the reaction molar ratio of Mg / Si and the order of injection acted as main factors for the change of average particle size. The average particle size of magnesium silicate increased by 8.7 ㎛ from 54.4 ㎛ to 63.1 ㎛ at Mg injection when Mg molar ratio increased from 0.125 to 0.500, and increased by about 4.8 ㎛ from 47.3 ㎛ to 52.1 ㎛ at Si injection. The average particle size according to the order of injection was 59.1 ㎛ for Mg injection and 48.4 ㎛ for Si injection and the difference was shown 10.7 ㎛, therefore the filtration rate was about 2 times faster under the condition of Mg injection. That is, as the particle size increases, the filtration time is shortened and washing filtration rate can be increased to improve the productivity of magnesium silicate. The cake form of separated magnesium silicate after filtration becomes a solid through drying process and is used as powdery adsorbent through the grinding process. As the physical strength of the dried magnesium silicate increased, the average particle size of the powder increased and it was confirmed that this strength was affected by the reaction molar ratio. As the reaction molar ratio of Mg / Si increased, the physical strength of magnesium silicate decreased and the average particle size after grinding decreased by about 40% compared to the average particle size after synthesis. This reduction of strength resulted in an improvement of the refining ability due to the decrease of the average particle size and the increase of the amount of fine particle after the pulverization, but it resulted in the decrease of the purification filtration rate. While the molar ratio of Mg/Si was increased from 0.125 to 0.5 at Mg injection, the refining ability increased about 1.3 times, but the purification filtration rate decreased about 1.5 times. Therefore, in order to improve the productivity of magnesium silicate, the reaction molar ratio of Mg / Si should be increased, but in order to increase the purification filtration rate of the polyol, the reaction molar ratio should be decreased. In the synthesis parameters of magnesium silicate, the order of injection and the reaction molar ratio of Mg / Si are important factors affecting the changes in average particle size after synthesis and the changes of particle size after grinding due to the changes of compressive strength, therefore the synthetic parameter is an important thing that determines productivity and refining capacity.

• Progress in Medical Physics
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• v.14 no.2
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• pp.131-140
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• 2003

As the importance of accuracy in measurings of 3-D anatomical structures continues to be stressed, an objective and quantitative of assessing image quality and accuracy of 3-D volume-rendered images is required. The purpose of this study was to evaluate the quantitative accuracy of 3-D rendered images obtained with MDCT, scanned at various scanning parameters (scan modes, slice thicknesses and reconstruction slice thickness). Twelve clinically significant points that play an important role for the craniofacial bone in plastic surgery and dentistry were marked on the surface of a dry human skull. The direct distances between the reference points were defined as gold standards to assess the measuring errors of 3-D images. Then, we scanned the specimen with acquisition parameters of 300 mA, In kVp, and 1.0 sec scan time in axial and helical scan modes (pitch 3:1 and 6:1) at 1,25 mm, 2.50 mm, 3.75 mm and 5.00 mm slice thicknesses. We performed 3-D visualizations and distance measurements with volumetric analysis software and statistically evaluated the quantitative accuracy of distance measurements. The accuracy of distance measurements on the 3-D images acquired with 1.25, 2.50, 3,75 and 5.00 mm slice thickness were 48%, 33%, 23%, 14%, respectively, and those of the reconstructed 1.25 mm were 53%, 41%, 43%, 36% respectively. Meanwhile, there were insignificant statistical differences (P-value<0.05) in the accuracy of the distance measurements of 3-D images reconstructed with 1.25 mm thickness. In conclusion, slice thickness, rather than scan mode, influenced the quantitative accuracy of distance measurements in 3-D rendered images with MDCT. The quantitative analysis of distance measurements may be a useful tool for evaluating the accuracy of 3-D rendered images used in diagnosis, surgical planning, and radiotherapeutic treatment.