• Toxicological Research
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• 제17권4호
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• pp.255-265
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• 2001

Epidemiologic studies have demonstrated an association between short-term exposure to particulate air pollutants and increased mortality. However the biological mechanism underlying these associations have not been fully established and also the chemical and physical characteristics of the pollutant particles are not well understood. The metal constituents of air pollutant particles and their bioavailability are considered to Play an important role as possible mediators of Particle-induced airway injury and inflammation. Sprague-Dawley rat alveolar macrophage cells (NR8383) were exposed to airborne and acid-leached particulate matter (PM). Titanium oxide and nickel subsulfide were used as negative and positive controls. Particle-induced reactive oxygen species formation in cells was detected using the fluorescent probe 2',7'-dichlorofluorescin diacetate. Expression of TNF-$\alpha$ and IL-6 were measured by enzyme-linked immunosorbent assay, and PM-induced DNA double-strand breaks were determined with $\lambda$DNA/Hind III marker. Metals associated with air pollutant particles mediated intracellular oxidant production in alveolar macrophages, and the cytotoxicity and proinflammatory cytokine production induced by PM were associated with oxidative stress. The oxidants produced by air pollutant particles also are likely to induce DNA double-strand breaks. Our findings in alveolar macrophage cells exposed to PM and acid-leached PM support the hypothesis that metal components in urban air pollutants and their bioavailabilities might play an Important role in the induction of the adverse health effects.

• 대한후두음성언어의학회지
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• 제8권2호
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• pp.217-224
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• 1997

The present study was performed to investigate the voice onset time(VOT) of Korean stop consonants as the expanded research of Pyo and Choi(1996) : the intensity, and the air flow rate of Korean stops as the preliminary study f3r the classical singing training. Nine Korean stops(/P, P', $P^{h}$/, /t, t', $t^{h}$/, /k, k', $k^{h}$/) and a vowel /a/ were used as speech materials. CV and VCV syllable patterns were used for VOT measurement, and CV pattern was used for intensity and air flow rate measurement. Five males and five females pronounced the speech tasks with comfortable pitch and intensity : VOT, intensity, and air flow rate were measured. As results, the prevocalic stop consonants showed bilabials, the shortest VOT and velars, the longest one, except the unaspirated stops which showed the shortest was velar /k'/, and the alveolar /t'/ was the longest. Considering the tensity, heavily aspirated stops showed the longest, and the unaspirated, the shortest. Also the intervocalic stops showed similar results with the prevocalic stops, except the slightly aspirated stops which showed alveolar sound was the longest, and the bilabials, which showed the shortest was the slightly aspirated /p/, unlike the prevocalic stops, the unaspirated /p'/ the shortest. All of prevocalic stops showed the highest air flow rate in heavily aspirated stops, the second, thee slightly aspirated ones, and the lowest was the unaspirated stops. And as a whole, bilabials were the highest, and velars, the lowest, except in the heavily aspirated stops, which was the alveolar sound, the lowest. In the dimension of intensity, the unaspirated and bilabials were the highest, and the heavily aspirated and velars were e lowest, except the slightly aspirated stops, which were the bilabials the lowest, and the alveolars the highest.

• 한국환경과학회지
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• 제7권5호
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• pp.615-622
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• 1998

생마늘과 김치에서 발생되는 휘발성 유기화합물에 대해 열흡탈착 혹은 퍼지/트랩을 이용한 가스크로마토그래프/질량선택성 검출기법에 의해 분석하였다. 메틸알릴 황, 이메틸 황, 이메틸 이황, 이알릴 황, 이알릴 이황, 메틸알릴 이황, 이알릴 이황 및 이메틸 삼황과 같은 대단히 악취가 강한 성분이 검출되었으며 이들 중 이메틸 이황과 이메틸 삼황은 김치의 숙성과정이나 마늘이 아닌 김치의 재료에서 발생된 것으로 추정되었다. 마늘이나 김치에서 발생되는 악취성분은 우리나라 사람의 입김이나 김치를 보관하는 냉장고 안의 공기 중에서도 검출되었다. 한국인의 입냄새나 냉장고 안의 냄새의 원인은 마늘이나 김치에서 발생되는 이황 화합물이 주성분으로 판단되었다. 이러한 냄새를 없애주는 간단한 방법으로 마늘이나 김치를 열처리하는 것이 대단히 효과가 있음이 밝혀졌다.

• 한국발생생물학회지:발생과생식
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• 제26권4호
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• pp.155-163
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• 2022

Human pluripotent stem cells (hPSCs) can give rise to a vast array of differentiated derivatives, which have gained great attention in the field of in vitro toxicity evaluation. We have previously demonstrated that hPSC-derived alveolar epithelial cells (AECs) are phenotypically and functionally similar to primary AECs and could be more biologically relevant alternatives for assessing the potential toxic materials including in fine dust and cigarette smoking. Therefore, in this study, we employed hPSC-AECs to evaluate their responses to exposure of various concentrations of diesel particulate matter (dPM), cigarette smoke extract (CSE) and nicotine for 48 hrs in terms of cell death, inflammation, and oxidative stress. We found that all of these toxic materials significantly upregulated the transcription of pro-inflammatory cytokines such as IL-1α, IL-β, IL-6, and TNF-α. Furthermore, the exposure of dPM (100 ㎍/mL) strongly induced upregulation of genes related with cell death, inflammation, and oxidative stress compared with other concentrations of CSE and nicotine. These results suggest that hPSC-AECs could be a robust in vitro platform to evaluate pulmotoxicity of various air pollutants and harmful chemicals.

• Tuberculosis and Respiratory Diseases
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• 제78권4호
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• pp.360-362
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• 2015

Spontaneous pneumomediastinum (PM) is an uncommon condition in which free air enters the mediastinum. This usually occurs either through esophageal tears after vigorous vomiting, or after alveolar rupture subsequent to a rapid increase in intra-alveolar pressure. Spontaneous PM is a rare entity in anorexia nervosa (AN) and self-induced vomiting is often the cause of PM in patients with AN. We experienced a case of spontaneous PM in an anorexic adolescent, in whom vomiting was not the cause of PM.

• 환경위생공학
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• 제7권2호
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• pp.95-110
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• 1992

Much progress has been made in understanding the subcellular events of the human lung injuries after acute exposure to environmental air pollutants. Host of those events represent oxidative damages mediated by reactive oxygen species such as superoxide, hydrogen peroxide, and the hydroxy, free radical. Recently, nitric oxide (NO) was found to be endogenously produced by endothelial cells and cells of the reticulo-endothelial system as endothelialderived relaxation factor (EDRF) which is a vasoactive and neurotransmitter substance. Together with superoxide, NO can form another strong oxidant, peroxonitrite. The relative importance of exogenous sources of $N0/N0_2$ and endogenous production of NO by the EDRF producing enzymes in the oxidative stresses to the heman lung has to be elucidated. The exact events leading to chronic irreversible damage are still yet to be known. From chronic exposure to oxidant gases, progressive epithelial and interstitial damages develop. Type I epithelial cells become thicker and cover a smaller average alveolar surface area while thee II cells proliferate instead. Under acute damages, the extent of loss of the alveolar epithelial cell lining, especially type II cells appears to be a good predictor of the ensuing irreversible damage to alveolar compartment. Interstitial matrix undergo remodeling during chronic exposure with increased collagen fibers and interstitial fibroblasts. However, Inany of these changes can be reversed after cessation of exposure. Among chronic lung injuries, genetic damages and repair responses received particular attention in view of the known increased lung cancer risks from exposure to several air pollutants. Heavy metals from foundry emission, automobile traffics, and total suspended particulate, especially polycystic aromatic hydrocarbons have been positively linked with the development of lung cancer. Asbestos in another air pollutant with known risk of lung cancer and mesothelioma, but asbestos fibers are nonauthentic in most bioassays. Studies using the electron spin resonance spin trapping method show that the presence of iron in asbestos accelerates the production of the hydroxy, radical in vitro. Interactions of these reactive oxygen species with particular cellular components and disruption of cell defense mechanisms still await further studies to elucidate the carcinogenic potential of asbestos fibers of different size and chemical composition. The distribution of inhaled pollutants and the magnitude of their eventual effects on the respiratory tract are determined by pollutant-independent physical factors such as anatomy of the respiratory tract and level and pattern of breathing, as well as by pollutant-specific phyco-chemical factors such as the reactivity, solubility, and diffusivity of the foreign gas in mucus, blood and tissue. Many of these individual factors determining dose can be quantified in vitro. However, mathematical models based on these factors should be validated for its integrity by using data from intact human lungs.

• 한국환경보건학회지
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• 제35권1호
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• pp.21-35
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• 2009

The Asian dust storms which originated in the deserts of Mongolia and China transported particles to Korea and led to a high concentration of atmospheric particulate matters (PM) of more than $1000{\mu}g/m^3$ throughout the country in the spring, of 2007. Public concern, in Korea, about the possible adverse effects of these dust events has increased, as these dust storms can contain various air pollutants emitted from heavily industrialized eastern China. The objectives of this study were to understand the concentration characteristics of PM as a function of particle size between the Asian dust storm episodes and non-Asian dust period and to consider the mass size distribution of PM in the Asian dust storms and their water soluble ion species on the potential, possible effects on deposition levels in the three regions (nasopharyngeal, tracheobronchial, and alveolar) of the human respiratory system. The size distribution of PM mass concentration during the Asian dust storms showed a peak in the coarse particle region due to the long-range transport of soil particles from the deserts of Mongolia and China, which was identified by HYSPLIT-4 model for backward trajectory analysis of air arriving in the sampling site of Iksan. During the non-Asian dust period, there were two different types in PM size distribution: bimodal distribution when low concentrations of $PM_{2.5}$ were observed, while unimodal distribution having a peak in fine particle region when high concentrations of $PM_{2.5}$ were showed. This unimodal distribution with high concentrations of fine particulate and secondary air pollutants such as ${SO_4}^{2-}$, ${NO_3}^-$, ${NH_4}^+$ was found to be due to the long-range transport of air pollutants from industrialized eastern China. During the Asian dust storms, the mean concentrations of PM that can be deposited in the nasopharyngeal, tracheobronchial, and alveolar region were $128.8{\mu}g/m^3$, $216.5{\mu}g/m^3$, and $89.6{\mu}g/m^3$, respectively. During the non-Asian dust period, the mean concentrations of PM that can be deposited in the nasopharyngeal, tracheobronchial, and alveolar region were $8.4{\mu}g/m^3$, $9.5{\mu}g/m^3$ and $38.5{\mu}g/m^3$, respectively.

• The Korean Journal of Physiology
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• 제1권1호
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• pp.73-76
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• 1967

A nomogram of gas exchange ratio (R) in air breathing subjects ,was porposed which enables a simple and rapid determination of R value using the fractional concentrations of nitrogen and carbon dioxide in the expired or alveolar gas. The readable limit of R value seems less than 1/100 of R unit and the average difference between the values from the nomogram and the actually calculated values is less than 0.005 of R unit. The usefulness of this nomogram for rapid and frequent determinations of the oxygen uptake is also suggested.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2002년도 추계학술대회 논문집
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• pp.358-359
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• 2002

Particulate matter smaller than $10{\mu}textrm{m}$ in aerodynamic diameter (PM10) is known as thoracic particles that are capable of reaching the thoracic region of humans. PM10 is further divided into two size ranges, which are fine particles (nuclei mode plus accumulation mode) and coarse particles, based on different sources and chemical composition. Fine particles can penetrate deep into the alveolar region of the human lungs, while coarse particles be deposited in the upper respiratory system. (omitted)

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 춘계학술대회 논문집
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• pp.251-252
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• 2003

Most particles capable of reaching the thoracic region of humans are in the size range below 10$\mu$m in diameter. Particles with a diameter smaller than 2.5 $\mu$m are deposited in large amounts in the alveolar region during mouth inhalation. The hazard caused by fine particles depends on their chemical composition and the site within the human respiratory system where they are deposited(Hinds, 1982). Therefore, the concentration of air borne fine particles is an important parameter for the evaluation of the degree of hazard in an atmospheric environment. (omitted)