• International Journal of Vascular Biomedical Engineering
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• v.4 no.1
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• pp.9-16
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• 2006

In this article we introduce computer models that have been developed in the past to determine the concentration of metabolic gases, the oxygen and carbon dioxide, along the pulmonary circulation. The terminal concentration of these gases in the arterial blood is related with the total change of the partial pressure of the same gases in the alveoli for the time beginning with inspiration and ending with expiration. It is affected not only by the ventilation-perfusion ratio and the gas diffusion capacity of the lung membrane but also by the pulmonary defect such as shunt, dead space, diffusion impairment and ventilation-perfusion mismatch. Some pathological pulmonary symptoms such as ARDS and CDPD can be understood through the mathematical models of these pulmonary dysfunctions. Quantitative study on the blood oxygenation process using various computer models is therefore of foremost importance in order to monitor not only the pulmonary health but also the cardiac output and cell metabolism. Reviewed in this paper include the basic and advanced methods that enable numerical study on the gas exchange and on the arterial oxygenation process, which might depend on the various heart and lung physiological conditions listed above.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.896-901
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• 1998

Pulmonary arteriovenous malformation(PAVM) is an uncommon congenital anomaly. As pulmonary arteriovenous malformation is a direct communication between the branches of pulmonary artery and vein which originated from the malformation of capillary development, major disturbances in gas exchange can result. This malformation results in the several symptoms such as dyspnea, hemopyssis, cyanosis, and severe neurologic complaints. However, the most of patients are usually asymptomatic. Selective pulmonary angiography is well known the helpful diagnostic method. Recently, therapeutic embolization has been advocated as the treatment of choice for pulmonary arteriovenous malformations. We report a case of multiple pulmonary arteriovenous malformation, which was detected on the simple chest X-ray and successfully treated with coil embolization in a 19-year-old asymptomatic woman.

• Journal of Korean Academy of Nursing
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• v.31 no.2
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• pp.257-267
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• 2001

It is known that a pulmonary rehabilitation program improves dyspnea and exercise tolerence in patients with chronic obstructive pulmonary disease. However, it is also known that although it does not improve pulmonary function. This study was performed to evaluate the effect of a 4 week pulmonary rehabilitation on pulmonary function, gas exchange, and exercise tolerance in patients with chronic obstructive pulmonary disease. The pulmonary rehabilitation programs included breathing exercises, such as pursed-lip breathing and diaphragmatic breathing, upper-limb exercises, and inspiratory muscle training. These activities were performed for 4 weeks in twenty one patients with chronic obstructive pulmonary disease. Pre and post-rehabilitation pulmonary function and exercise capacities were compared after the 4 week period. Results are as follows: 1) Before the rehabilitation, the predicted value of FVC and FEV1 of the patients were 70.3$\pm$16.7% and 41.1$\pm$11.9% respectively. These pulmonary functions did not change after pulmonary rehabilitation. 2) Aloility of walking a 6 minute distance (325.29$\pm$122.24 vs 363.03$\pm$120.01 p=.01) and dyspnea (p=.00) were significantly improved after rehabilitation. Thus showing that pulmonary rehabilitation for 4 weeks can improve exercise performance and dyspnea in patients with chronic obstructive pulmonary disease.

• Biomedical Science Letters
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• v.27 no.3
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• pp.111-120
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• 2021

Asbestos products had been widely used until 2007 in Korea since the 1930s. A total ban on their production and applications has been imposed because of the toxic effect of asbestos fibers on the human health. The inhaled asbestos fibers increase reactive oxygen species and inflammatory reactions in the respiratory airway including the alveolar sac, resulting in DNA damages and secretion of several inflammatory cytokines or chemokines. These paracrine communications promote the proliferation of fibroblasts and the synthesis of collagen fibers, thereby depositing them into the extracellular matrix at the interstitial space of alveoli. The fibrotic tissue hindered the gas exchange in the alveolus. This reviews describes not only the cytotoxic effects of asbestos fibers with different physical or chemical characteristics but also the interaction of cells that make up the respiratory airway to understand the molecular or cellular mechanisms of asbestos fiber-induced toxicity. In addition, we propose a pulmonary toxicity research technique based on the mini-lung that can mimic human respiratory system as an alternative to overcome the limitations of the conventional risk assessment of asbestos fibers.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.154-160
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• 2004

The purpose of this study was to evaluate airborne concentrations and characteristics of TSP, IPM, TPM and RPM in Seoul subway stations. Sampling was performed at 14 stations from April 11 to 29, 2002. Size-selective dust concentrations and metal concentrations were measured by gravimetric method and ICP-AES, respectively. The geometric mean of TSP, IPM, TPM and RPM concentrations in Seoul subway stations were 176$\mu\textrm{g}$/㎥, 348$\mu\textrm{g}$/㎥, 158$\mu\textrm{g}$/㎥ and 104$\mu\textrm{g}$/㎥, respectively. Dust concentrations in pathway were the highest and those in lobby were the lowest. The size distribution of dusts was significantly different by location of collection. When the deposition rate into pulmonary gas exchange region was estimated by size distribution, the deposition rate of dust collected from platform was higher than those of dust collected from lobby and pathway. The lower the basement levels were, the higher the deposition rates of dusts into tracheobronchial region and gas exchange region were. Copper and iron concentrations measured in platform higher were than those in other areas.

• International Journal of Stem Cells
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• v.17 no.1
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• pp.30-37
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• 2024

The lung is a complex organ comprising a branched airway that connects the large airway and millions of terminal gas-exchange units. Traditional pulmonary biomedical research by using cell line model system have limitations such as lack of cellular heterogeneity, animal models also have limitations including ethical concern, race-to-race variations, and physiological differences found in vivo. Organoids and on-a-chip models offer viable solutions for these issues. Organoids are three-dimensional, self-organized construct composed of numerous cells derived from stem cells cultured with growth factors required for the maintenance of stem cells. On-a-chip models are biomimetic microsystems which are able to customize to use microfluidic systems to simulate blood flow in blood channels or vacuum to simulate human breathing. This review summarizes the key components and previous biomedical studies conducted on lung organoids and lung-on-a-chip models, and introduces potential future applications. Considering the importance and benefits of these model systems, we believe that the system will offer better platform to biomedical researchers on pulmonary diseases, such as emerging viral infection, progressive fibrotic pulmonary diseases, or primary or metastatic lung cancer.

• Journal of Korean Academy of Nursing
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• v.21 no.2
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• pp.204-217
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• 1991

The purpose of this study is to verify the effect of lateral position and chest percussion on gas exchange in the decreased level of conscious patients. The Subjects for this study were 21 patients' admitted in ICU of CNUH from Dec 18th, 1989 to Aug 4th, 1990. The Data was analyzed by paired t - test. The results of this study as follows ; 1) In comparison of supine position, good -lung dependent position and good - lung dependent with chest percussion, the difference of PaO ㆍ was statistically significant (P＜0.05). 2) In comparison of supine position, good -lung dependent position and good - lung dependent with chest percussion, the difference of A-a Do ㆍ was statistically significant (p＜0.05). En conclusion, the use of good -lung dependent position and chest percussion was effective nursing intervention on decreased level of conscious patients in ICU.

• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.5-13
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• 2005

Chronic obstructive pulmonary disease (COPD) is a chronic progressive disease, characterized by irreversible airflow limitation, with a partially reversible component. The pathological abnormalities of COPD are associated with lung inflammation, imbalances of proteinase and antiproteinase, and oxidative stress, which are induced by noxious particles and gases in susceptible individuals. The physiological changes of COPD are mucus hypersecretion, ciliary dysfunction, airflow limitation, pulmonary hyperinflation, gas exchange abnormalities, pulmonary hypertension, cor pulmonale and systemic effects. The airflow limitation principally results from an increase in the resistance of the small conducting airways and a decrease in pulmonary elastic recoil due to emphysematous lung destruction. This article provides a general overview of the pathophysiology of COPD.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1223-1235
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• 1998

Background and Objective : Although prone positioning has been reported to improve gas exchange, prone positioning alone does not seem to be sufficient to increase systemic oxygen transport in an acute lung injury. The objective of this study was to investigate whether the combined therapy of low dose nitric oxide (NO) inhalation and prone positioning has an additive effect on the oxygenation and hemodynamics in patients with severe ARDS. Patients and Methods : Twelve patients with ARDS were included. Prone positioning alone, later combined with nitric oxide inhalation (5~10 ppm) from the supine position (baseline) were performed with serial measurement of gas exchange, respiratory mechanics and hemodynamic at sequential time points. The patient was regarded as a responder to prone positioning if an increase in $PaO_2/FiO_2$ of more than 20 mm Hg at 30 min or 120 min intervals after prone positioning was observed compared to that of the baseline. The same criterion was applied during nitric oxide inhalation. Results : Eight patients (66.5%) responded to prone positioning and ten patients (83.3%) including the eight just mentioned responded to the addition of NO inhalation. The $AaDO_2$ level also decreased promptly with the combination of prone positioning and NO inhalation compared to that of prone positioning alone ($191{\pm}109$ mm Hg vs. $256{\pm}137$ mm Hg, P<0.05). Hemodynamic parameters and lung compliance did not change significantly during prone positioning only. Following the addition of NO inhalation to prone positioning, the mean pulmonary artery pressure and pulmonary artery occlusion pressure decreased and cardiac output, stroke volume and oxygen delivery increased (P < 0.05) compared to those of prone 120 min. Conclusion : These findings indicate that NO inhalation would provide additional improvement in oxygenation and oxygen transport to mechanically ventilated patients with ARDS who are in a prone position.

• Tuberculosis and Respiratory Diseases
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• v.68 no.3
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• pp.125-139
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• 2010

Patients with chronic obstructive pulmonary disease (COPD) frequently complain of dyspnea on exertion and reduced exercise capacity, which has been attributed to an increase in the work of breathing and in impaired of gas exchange. Although COPD primarily affects the pulmonary system, patients with COPD exhibit significant systemic manifestations of disease progression. These manifestations include weight loss, nutritional abnormalities, skeletal muscle dysfunction (SMD), cardiovascular problems, and psychosocial complications. It has been documented that SMD significantly contributes to a reduced exercise capacity in patients with COPD. Ventilatory and limb muscle in these patients show structural and functional alteration, which are influenced by several factors, including physical inactivity, hypoxia, smoking, aging, corticosteroid, malnutrition, systemic inflammation, oxidative stress, apoptosis, and ubiquitin-proteasome pathway activation. This article summarizes briefly the evidence and the clinical consequences of SMD in patients with COPD. In addition, it reviews contributing factors and therapeutic strategies.