Nasal and Pulmonary Toxicity of Titanium Dioxide Nanoparticles in Rats

Kwon, Soonjin,Yang, Young-Su,Yang, Hyo-Seon,Lee, Jinsoo,Kang, Min-Sung,Lee, Byoung-Seok,Lee, Kyuhong,Song, Chang-Woo Korean Society of ToxicologyKorea Environmental Mu 2012 Toxicological Research Vol.28 No.4

In recent decades, titanium dioxide ($TiO_2$) nanoparticles have been used in various applications, including paints, coatings, and food. However, data are lacking on the toxicological aspects associated with their use. The aim of this study was to assess the inhalation toxicity of $TiO_2$ nanoparticles in rats by using inhalation exposure. Male Wistar rats were exposed to $TiO_2$ nanoparticles for 2 weeks (6 hr/day, 5 days/week) at a mean mass concentration of $11.39{\pm}0.31mg/m^3$. We performed time-course necropsies at 1, 7, and 15 days after exposure. Lung inflammation and injury were assessed on the basis of the total and individual cell counts in bronchoalveolar lavage fluid (BALF), and by biochemical assays, including an assay for lactate dehydrogenase (LDH). Furthermore, histopathological examination was performed to investigate the lungs and nasal cavity of rats. There were no statistically significant changes in the number of BALF cells, results of biochemical assays of BALF and serum, and results of cytokine analysis. However, we did observe histopathological changes in the nasal cavity tissue. Lesions were observed at post-exposure days 1 and 7, which resolved at post-exposure day 15. We also calculated the actual amounts of $TiO_2$ nanoparticles inhaled by the rats. The results showed that the degree of toxicity induced by $TiO_2$ nanoparticles correlated with the delivered quantities. In particular, exposure to small particles with a size of approximately 20 nm resulted in toxicity, even if the total particle number was relatively low.

Nasal and Pulmonary Toxicity of Titanium Dioxide Nanoparticles in Rats

Soonjin Kwon,Young-Su Yang,Hyo-Seon Yang,Jinsoo Lee,Min-Sung Kang,Byoung-seok Lee,Kyuhong Lee,Chang-Woo Song 한국독성학회 2012 Toxicological Research Vol.28 No.4

In recent decades, titanium dioxide (TiO₂) nanoparticles have been used in various applications, including paints, coatings, and food. However, data are lacking on the toxicological aspects associated with their use. The aim of this study was to assess the inhalation toxicity of TiO₂ nanoparticles in rats by using inhalation exposure. Male Wistar rats were exposed to TiO₂ nanoparticles for 2 weeks (6 hr/day, 5 days/week) at a mean mass concentration of 11.39 ± 0.31 mg/㎥. We performed time-course necropsies at 1, 7, and 15 days after exposure. Lung inflammation and injury were assessed on the basis of the total and individual cell counts in bronchoalveolar lavage fluid (BALF), and by biochemical assays, including an assay for lactate dehydrogenase (LDH). Furthermore, histopathological examination was performed to investigate the lungs and nasal cavity of rats. There were no statistically significant changes in the number of BALF cells, results of biochemical assays of BALF and serum, and results of cytokine analysis. However, we did observe histopathological changes in the nasal cavity tissue. Lesions were observed at post-exposure days 1 and 7, which resolved at post-exposure day 15. We also calculated the actual amounts of TiO₂ nanoparticles inhaled by the rats. The results showed that the degree of toxicity induced by TiO₂ nanoparticles correlated with the delivered quantities. In particular, exposure to small particles with a size of approximately 20 nm resulted in toxicity, even if the total particle number was relatively low.

검색의도 파악을 위한 질의어 관계유형에 관한 사례연구

권순진(Soonjin Kwon),김원일(Wonil Kim),유성준(Seongjoon Yoo) 한국지능시스템학회 2011 한국지능시스템학회논문지 Vol.21 No.4

본 연구는 정보 검색(Information Retrieval)과정에 있어 검색 기술의 적합성을 향상하기 위하여, 질의어 사이의 유용한 관계를 드러내도록 사례를 분석하고, 질의자의 의도를 파악할 수 있게끔 구체화하도록 연구한 것이다. 이를 위하여 먼저, 질의어가 가지는 어휘 의미적 연구 분야와 존재론적 연구 분야의 관련 연구들을 분석하였으며, 국내ㆍ외의 어휘 의미론적 네트워크 사례와 정보 검색 기술이 적용된 사이트의 실제 데이터를 분석하여 관계 유형을 추출하고 분석하였다. 다음으로는 일반적으로 검색자가 직면하는 검색 상황에서 자주 발생하는 문제를 중심으로 문제점을 정의하여 해결 방안을 모색하였다. 현행 검색 기술에서 색인어와 질의어를 단순 비교하여 결과를 쏟아주는 검색은 사용자를 혼란하게 하기 때문에 개선이 필요하고, 질의자의 의도에 맞는 질의 결과를 줄 수 있도록 지능적 검색으로 개선할 필요가 있다. 문제점 해결 방안에 있어서는, 두 질의어 사이의 관계를 드러냄으로써, 검색자의 의도를 인식하고 식별 및 처리할 수 있는 방안이 필요하였다. 질의어들에 관한 실제 사례를 분석하고 관계 유형을 9가지로 분류함으로써, 관계 유형을 디자인하는 방법을 적시하였으며, 관계 유형의 명칭 부여와 관계 역할의 명칭을 부여할 수 있는 방법과 제한점도 예시하였다. IR (Information Retrieval) systems have the methods that compare relationships between query and index to identify document that may be fit to the user’s query keyword. However, the methods usually ignore the importance of relations that are not expressed in the query. Therefore, in this study, we describe how to refine the queries’ relation from keyword and to reveal the hidden intent. A useful relationship between query and keyword in IR wth studied and we classified the tion fromrelation. Firstfromall, we did researchmrelated on semantic relationship and ontolhiical researchmin foreign and domestic research, and also analyzed semantic network practices, information retrieval technolhiy, extracted and classified the tion fromrelationships s’ relasite’s real-world datamin whichminformation retrieval technolhiin fare applied. Next, we souiht to solve the problems occurred frequently i’ relasituation that searchers tioically face. I’ relacurrent search technolhiy, the mesh searchmresult fare poured by simply comparn ina query with index terms. Therefore, the need for an intelligent search fittn inusers’ intent is required. The relationships between two queries to re hiddee and identify relasearcher’s intent have to be revealed. By analyzn inthe practical cthes s’ queries and classifyn inthem into nine kind fromrelationship tion, we proposed the method to design relation revealn inand role namn i, and we have also illustrated limitations of that methods.

효율적 검색의도 파악을 위한 쿼리 단어 가시화에 관한 연구

권순진(Soonjin Kwon),홍철의(Chuleui Hong),김원일(Wonil Kim) 大韓電子工學會 2012 電子工學會論文誌-CI (Computer and Information) Vol.49 No.2

본 논문은 검색 질의어 단어 입력 시에 드러나지 않은 쿼리 단어들을 가시화함으로써, 검색 주체의 의도 구조를 선택할 수 있게 하며, 탐색 효율을 제고하도록 제안한다. 검색 질의어를 입력할 때 검색 의도를 파악한다면 효과적인 검색 서비스가 가능할 것이다. 이렇게 하기 위하여, 의도 구조와 요소를 설정함과 아울러 쿼리 단어의 생략된 관계에 해당하는 단어를 복원하여 가시화하는 과정이 필요하다. 관련된 연구들을 검토하며, 검색 의도 구조를 정의하고, 쿼리 단어의 가시화를 위한 방법과 의도 구조에 적합한 쿼리 단어를 확장 생성하는 과정을 보인다. 이 과정에서 의도 구조의 여러 계층 중 하나를 쿼리 단어 범위로 할당하는 예제와 실험을 수행하였다. 탐색 효율 상승의 검색결과와 탐색효율 하락의 검색결과를 분석하였다. 향후 연구로는 의도 결절을 확장하여 구성 요소를 학습할 수 있도록 자동화하는 연구가 필요하다. This paper proposes to increase an efficiency of somebody searching information by a visualization of an unseen query words with well-selected user's intent structures. If a search engine identifies user's intent to pursue information, it would be an effective search engine. To do so, it is needed that relationships between query-words are to be visible after recovering words lost during formulated, and that an intention structure/elements is to be established. This paper will review previous studies, after then, define a simple structure of the search intent, and show a process to expand and to generate the query words appropriate to the intent structure with a method for the visualization of the query words. In this process, some examples and tests are necessary that one of the multiple intent structured layers is to assign to a range of query-words. Increasing/Decreasing an efficiency are analyzed to find. Future research is needed how to automate a process to extend structural nodules of user's intent.

LC50 Determination of tert-Butyl Acetate using a Nose Only Inhalation Exposure in Rats

양영수,Jinsoo Lee,Soonjin Kwon,Heung-Sik Seo,최성진,Hee-Jin Yu,송정아,Kyuhong Lee,Byoung-Seok Lee,Jeong-Doo Heo,Kyu-Hyuk Cho,송창우 한국독성학회 2010 Toxicological Research Vol.26 No.4

tert-Butyl acetate (TBAc) is an organic solvent, which is commonly used in architectural coatings and industrial solvents. It has recently been exempted from the definition of a volatile organic compound (VOC) by the Air Resources Board (ARB). Since the use of TBAc as a substitute for other VOCs has increased, thus its potential risk in humans has also increased. However, its inhalation toxicity data in the literature are very limited. Hence, inhalation exposure to TBAc was carried out to investigate its toxic effects in this study. Adult male rats were exposed to TBAc for 4 h for 1 day by using a nose-only inhalation exposure chamber (low dose, 2370 mg/m3 (500 ppm); high dose, 9482 mg/m3 (2000 ppm)). Shamtreated control rats were exposed to clean air in the inhalation chamber for the same period. The animals were killed at 2, 7, and 15 days after exposure. At each time point, body weight measurement, ronchoalveolar lavage fluid (BALF) analysis, histopathological examination, and biochemical assay were performed. No treatment-related abnormal effects were observed in any group according to time course. Based on those findings, the median lethal concentration (LC50) of TBAc was over 9482 mg/m3 in this study. According to the MSDS, the 4 h LC50 for TBAc for rats is over 2230 mg/m3. We suggested that this value is changed and these findings may be applied in the risk assessment of TBAc which could be beneficial in a sub-acute study.

LC₅₀ Determination of tert-Butyl Acetate using a Nose Only Inhalation Exposure in Rats

Young-Su Yang,Jinsoo Lee,Soonjin Kwon,Heung-Sik Seo,Seong-Jin Choi,Hee-Jin Yu,Jeong-Ah Song,Kyuhong Lee,Byoung-Seok Lee,Jeong-Doo Heo,Kyu-Hyuk Cho,Chang-Woo Song 한국독성학회 2010 Toxicological Research Vol.26 No.4

tert-Butyl acetate (TBAc) is an organic solvent, which is commonly used in architectural coatings and industrial solvents. It has recently been exempted from the definition of a volatile organic compound (VOC) by the Air Resources Board (ARB). Since the use of TBAc as a substitute for other VOCs has increased, thus its potential risk in humans has also increased. However, its inhalation toxicity data in the literature are very limited. Hence, inhalation exposure to TBAc was carried out to investigate its toxic effects in this study. Adult male rats were exposed to TBAc for 4 h for 1 day by using a nose-only inhalation exposure chamber (low dose, 2370 ㎎/㎥ (500 ppm); high dose, 9482 ㎎/㎥ (2000 ppm)). Sham-treated control rats were exposed to clean air in the inhalation chamber for the same period. The animals were killed at 2, 7, and 15 days after exposure. At each time point, body weight measurement, bronchoalveolar lavage fluid (BALF) analysis, histopathological examination, and biochemical assay were performed. No treatment-related abnormal effects were observed in any group according to time course. Based on those findings, the median lethal concentration (LC??) of TBAc was over 9482 ㎎/㎥ in this study. According to the MSDS, the 4 h LC?? for TBAc for rats is over 2230 ㎎/㎥. We suggested that this value is changed and these findings may be applied in the risk assessment of TBAc which could be beneficial in a sub-acute study.

Standardization of Bronchoalveolar Lavage Method Based on Suction Frequency Number and Lavage Fraction Number Using Rats

Jeong-Ah Song,Hyo-Seon Yang,Jinsoo Lee,Soonjin Kwon,Kyung Jin Jung,Jeong-Doo Heo,Kyu-Hyuk Cho,Chang Woo Song,Kyuhong Lee 한국독성학회 2010 Toxicological Research Vol.26 No.3

Bronchoalveolar lavage (BAL) is a useful tool in researches and in clinical medicine of lung diseases because the BAL fluid contains biochemical and cytological indicators of the cellular response to infection, drugs, or toxicants. However, the variability among laboratories regarding the technique and the processing of the BAL material limits clinical research. The aim of this study was to determine the suction frequency and lavage fraction number necessary to reduce the variability in lavage using male Sprague-Dawley rats. We compared the total cell number and protein level of each lavage fraction and concluded that more cells and protein can be obtained by repetitive lavage with a suction frequency of 2 or 3 than by lavage with a single suction. On the basis of total cell recovery, approximately 70% of cells were obtained from fractions 1~3. The first lavage fraction should be used for evaluation of protein concentration because fractions 2~5 of lavage fluid were diluted in manifolds. These observations were confirmed in bleomycin-induced inflamed lungs of rats. We further compared the BAL data from the whole lobes with data from the right lobes and concluded that BAL data of the right lobes represented data of the whole lobes. However, this conclusion can only be applied to general lung diseases. At the end, this study provides an insight into the technical or analytical problems of lavage study in vivo.

Dose-response Effects of Bleomycin on Inflammation and Pulmonary Fibrosis in Mice

Soo Nam Kim,Jinsoo Lee,Hyo-Seon Yang,Jae-Woo Cho,Soonjin Kwon,Young-Beom Kim,Jeong-Doo Her,Kyu-Hyuk Cho,Chang-Woo Song,Kyuhong Lee 한국독성학회 2010 Toxicological Research Vol.26 No.3

Many studies have reported that bleomycin, anti-cancer drug, induces pulmonary fibrosis as a side effect. However, few investigations have focused on the dose-response effects of bleomycin on pulmonary fibrosis. Therefore, in the present study, we investigated the effects of different doses of bleomycin in male mice. ICR mice were given 3 consecutive doses of bleomycin: 1, 2, or 4 ㎎/㎏ in bleomycin-treated (BT) groups and saline only in vehicle control (VC) groups. The animals were sacrificed at 7 and 24 days postinstillation. The severity of pulmonary fibrosis was evaluated according to inflammatory cell count and lactate dehydrogenase (LDH) activity in the broncho alveolar lavage fluid (BALF), and lung tissues were histologically evaluated after hematoxylin and eosin (H&E), and Masson’s trichrome staining. BT groups exhibited changed cellular profiles in BAL fluid compared to the VC group, which had an increased number of total cells, neutrophils, and lymphocytes and a modest increase in the number of macrophages at 7 days post-bleomycin instillation. Moreover, BT groups showed a dose-dependent increase in LDH levels and inflammatory cell counts. However, at 24 days after treatment, collagen deposition, interstitial thickening, and granulomatous lesions were observed in the alveolar spaces in addition to a decrease in inflammatory cells. These results indicate that pulmonary fibrosis induced by 4 ㎎/㎏ bleomycin was more severe than that induced by 1 or 2 ㎎/㎏. These data will be utilized in experimental animal models and as basic data to evaluate therapeutic candidates through non-invasive monitoring using the pulmonary fibrosis mouse model established in this study.

ACUTE INHALATION TOXICITY STUDY WITH TOLUENE IN RATS

Heung-Sik Seo,Young-Su Yang,Jinsoo Lee,Min-Sung Kang,Soonjin Kwon,Seong-Jin Choi,Soo-Nam Kim,Byeong-Chan Lee,Hyo-Seon Yang,Yong-Ah Han,Hee-Jin Yu,Jae-Hwan Kim,Jin-Hee Lee,Jeong-Ah Song,Kyung Jin Jung 한국환경독성학회 2009 한국독성학회 심포지움 및 학술발표회 Vol.2009 No.11

THE EFFECT OF ACUTE TOLUENE EXPOSURE ON HIPPOCAMPAL NEUROGENESIS IN ADULT RATS

Heung-Sik Seo,Young-Su Yang,Jinsoo Lee,Min-Sung Kang,Soonjin Kwon,Seong-Jin Choi,Soo-Nam Kim,Byeong-Chan Lee,Hyo-Seon Yang,Young-Ah Han,Hee-Jin Yu,Jae-Hwan Kim,Jin-Hee Lee,Jeong-Ah Song,Kyung Jin Jung 한국환경독성학회 2009 한국독성학회 심포지움 및 학술발표회 Vol.2009 No.11