• Title/Summary/Keyword: study model

Search Result 84,936, Processing Time 0.119 seconds

Removal Characteristics of Sulfonamide Antibiotic Compounds in Biological Activated Carbon Process (생물활성탄 공정에서의 Sulfonamide계 항생물질 제거특성)

  • Son, Hee-Jong;Jung, Jong-Moon;Roh, Jae-Soon;Yu, Pyung-Jong
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.31 no.2
    • /
    • pp.96-101
    • /
    • 2009
  • In this study, the effects of three different biological activated carbon (BAC) materials (each coal, coconut and wood based activated carbons), empty bed contact time (EBCT) and water temperature on the removal of sulfonamide 5 species in BAC filters were investigated. Experiments were conducted at three water temperatures (5, 15 and $25^{\circ}C$) and four EBCTs (5, 10, 15 and 20 min). The results indicated that coal based BAC retained more attached bacterial biomass on the surface of the activated carbon than the other BACs, increasing EBCT or increasing water temperature increased the sulfonamide 5 species removal in BAC columns. In the coal-based BAC columns, sulfachloropyridazine (SCP), sulfamethazine (SMT) and sulfathiazole (STZ) removal efficiencies were 30~80% and sulfadimethoxine (SDM), sulfamethoxazole (SMX) removal efficiencies were 18~70% for 5~20 min EBCT at $25^{\circ}C$. The kinetic analysis suggested a first-order reaction model for sulfonamide 5 species removal at various water temperatures (5~$25^{\circ}C$). The pseudo-first-order reaction rate constants and half-lives were also calculated for sulfonamide 5 species removal at 5~$25^{\circ}C$. The reaction rate and half-lives of sulfonamide 5 species ranging from 0.0094~0.0718 $min^{-1}$ and 9.7 to 73.7 min various water temperaturs and EBCTs in this study could be used to assist water utilities in designing and operating BAC filters for sulfonamide antibiotic compounds removal.

The influence of occlusal loads on stress distribution of cervical composite resin restorations: A three-dimensional finite element study (교합력이 치경부 복합레진 수복물의 응력분포에 미치는 영향에 관한 3차원 유한요소법적 연구)

  • Park, Chan-Seok;Hur, Bock;Kim, Hyeon-Cheol;Kim, Kwang-Hoon;Son, Kwon;Park, Jeong-Kil
    • Restorative Dentistry and Endodontics
    • /
    • v.33 no.3
    • /
    • pp.246-257
    • /
    • 2008
  • The purpose of this study was to investigate the influence of various occlusal loading sites and directions on the stress distribution of the cervical composite resin restorations of maxillary second premolar, using 3 dimensional (3D) finite element (FE) analysis. Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). HyperMesh (Altair Engineering, Inc., Troy, USA) and ANSYS (Swanson Analysis Systems, Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid (Z100, 3M Dental Products, St. Paul, MN, USA) or flowable resin (Tetric Flow, Vivadent Ets., FL-9494-Schaan, Liechtenstein) and each restoration was simulated with adhesive layer thickness ($40{\mu}m$). A static load of 200 N was applied on the three points of the buccal incline of the palatal cusp and oriented in $20^{\circ}$ increments, from vertical (long axis of the tooth) to oblique $40^{\circ}$ direction towards the buccal. The maximum principal stresses in the occlusal and cervical cavosurface margin and vertical section of buccal surfaces of notch-shaped class V cavity were analyzed using ANSYS. As the angle of loading direction increased, tensile stress increased. Loading site had little effect on it. Under same loading condition, Tetric Flow showed relatively lower stress than Z100 overall, except both point angles. Loading direction and the elastic modulus of restorative material seem to be important factor on the cervical restoration.

Summary and Conclusion Title :Oriental Nursing Management System (한방간호 관리체계 연구)

  • Moon, Heui-Ja
    • Journal of East-West Nursing Research
    • /
    • v.10 no.1
    • /
    • pp.11-26
    • /
    • 2004
  • The purpose of this study is to investigate the present conditions of nursing investment contents, its conversion process, and output in Oriental University Medical Center, Korea to get good qualified Oriental nursing result which is the ultimate purpose of the Oriental nursing management, and to develope a matrix of Oriental nursing management system on the basis of that project. The subjects for nursing investment and output contents were eighteen nursing directors in eleven Oriental University Medical Center and two hundred thirty-nine nurses with three years and over experience in Oriental medical center. The subjects for Oriental nursing organization, human affair management, and control function were nineteen Oriental medical center in Oriental University Medical Center, Korea. Data were collected from November, 2002 to February, 2003 with questionnaire. Data analysis was done by SPSS PC+ 12 program. Frequency, percentage, and minimum/maximum values were used for investment contents, and frequency and percentage were used for conversion process and output contents. 1. The input factors of oriental nursing management system The objective's western hospital career was over five years of one hundred and seventy-five(73.2%) persons. Nursing in-service education was performed in fourteen hospitals(77.8%). Two hundreds(83.7%) were pro to oriental nurse system. Only four hospitals(22.2%) had independent budget in nursing division. Nursing staff allocation to the bed was from 2.8:1 to 9.06:1 respectively, with a big gap of the rate following the hospitals. 2. The conversion factors of oriental nursing system 1) Oriental nursing system Oriental hospital nursing system was organized independently in ten hospitals among eighteen hospitals. The recruitment of nurses which was a vital role of the nursing division of the hospital was mostly(79%) opened. The education to develope nursing personnels was through in-service one in 97.4%. Education for oriental nursing and management was performed in 42.1%(eight hospitals) and that for reserves was done in 36.8%(seven hospitals). Administration for nursing education by nursing division was 68.5%(thirteen hospitals). The post education evaluation was performed by report submission in 36.8%(seven hospitals), by written examination in 26.3%, by questionnaires in 21.1%, and by lecture presentation in 15.8% subsequently. The directorial meeting for the nursing directors was attended by 84.2%(sixteen hospitals), and the meeting type was the medical executive and support division executive meeting in 55.6%(ten hospitals) and the personnel management in 39.6%(seven hospitals). 2) The actual conditions of oriental nursing personnel management The reason of working in oriental hospital was by voluntary in 67.1%(a hundred and sixty persons), by nursing department order in 28.0%(sixty-seven persons), and by others in 5.0%(twelve persons) respectively. The shift form was a three-shifts one in 94.7%(eighteen hospitals), a two-shift one in only one hospital. Duty assignment was functional in 52.6%(ten hospitals), team and functional in 26.3%(five hospitals) and no team alone. Promotion manual was present at 68.4%(thirteen hospitals) and the competency essentials comprised of performance evaluation in 79%, interview, written examination, training result, study result subsequently. No labor union existed in 79%(fifteen hospitals) 3) Oriental nursing preceptor system There were five oriental hospitals(27.7%) administering the preceptor utilization model, which showed lower rate than the twenty-two medical university hospitals in Seoul in which fifteen hospitals (72.7%) were having the system. To the question of necessity of oriental nurse system asked to the objectives of two hundred and thirty-nine with more than three year-experience in oriental hospital, two hundred persons(83.7%) answered positively. 4) The control of oriental nursing The evaluation results from the target hospitals were mostly not opened in 89.4% of oriental hospitals. Thirteen hospitals(68.3%) had evaluation system of direct managers and the next were three hospitals(15.8%) of direct managers and selves. There was one hospital(5.3% each) where fellows and superiors, fellows, and inferiors' evaluation was performed and no hospital where superiors, fellows, inferiors and selves, and superiors, fellows and selves' evaluation was performed. The QI activity of nursing was 42.1%(eight hospitals) for nursing service evaluation, 36.8% for survey of ECSI, 26.3% for survey of ICSI, 15.8% for medical visit rate, 10% for hospital standardization inspection in sequence. 3. The output factors of oriental nursing management system The job satisfaction appeared good in general, indicating very good in thirty-seven persons (15.7%), good in one hundred and fourteen persons (48.3%) and fair in eighty-five persons(36.0%).

  • PDF

The Experimental Study on the Immuno-regulatory effect of ASARI HERBA CUM RADICE Herbal- acupuncture at Pyesu(BL13) on OVA-induced asthma in mice (폐유(肺兪) 세신약침(細辛藥鍼)이 OVA-induced Asthma Mouse Model의 면역조절작용(免疫調節作用)에 미치는 영향)

  • Ryu, Eun-sang;Lee, Hyun;Lee, Byung-ryul
    • Journal of Acupuncture Research
    • /
    • v.22 no.3
    • /
    • pp.185-200
    • /
    • 2005
  • Objective : The aim of this study was to investigate the asthma-suppressive and immune-regulatory effect of AHCR-HA(ASARI HERBA CUM RADICE Herbal-acupuncture) at Pyesu(BLl3) on OVA(ovalbumin)-induced asthma in mice. Methods : C57BL/6 mice out of all the experimental groups, except the Normal group and the AHCR-HA group, were sensitized and challenged with OVA The mice in the AHCR-HA group and the OVA-AHCR-HA group were treated with AHCR-HA(1%) at Pyesu(BL13). The mice in the OVA-Saline group were injected with saline at Pyesu(BL13). The mice in the OVA-Needle-Prick group were treated with a single prick with an injection needle at Pyesu(BL13). AHCR-HA saline injection and needle prick were administered for 8 weeks, three times a week. Result : 1. The populations of granulocytes, CD3e-/CCR3+ cells, CD69+/CD3e+ cells, CD4+ cells and CD23+/B220+ cells in the OVA-induced asthmatic mouse lungs decreased significantly by AHCR-HA. 2. The lung weight, total cells in lung, total leukocytes in BALF, eosinophils in BALF, collagen accumulation in the lung sections of the OVA-AHCR-HA group decreased significantly. 3.The concentrations of IL-4, IL-5, IL-13, IgE in BALF and serum of the OVA-AHCR-HA group decreased significantly. 4. The numbers of Gr-1+/CD11b+, CCR3+, CD3e+, CD19+, CD3e+/CD69+cells in the OVA-AHCR-HA group decreased significantly. 5. The mRAN expressions of $TNF-{\alpha}$, IL-5, IL-4 and IL-13 in lung of the OVA-AHCR-HA group decreased significantly. 6. The AHCR-HA group didn't show any considerable difference from the Normal group. The OVA-saline group and the OVA-Needle prick group showed suppressive effects on OVA-induced asthma however they were not statistically significant. Conclusion : These results suggest that AHCR-HA at Pyesu(BL13) is considered to be effective in treating asthma and to be put to practical use in the future asthma clinic.

  • PDF

A study on the limit of orthodontic treatment (교정 치료의 한계에 관한 연구)

  • Kim, Sun-Ju;Park, So-Young;Woo, Hae-Hong;Park, Eun-Jie;Kim, Young-Ho;Lee, Shin-Jae;Moon, Seong-Cheol;Baek, Seung-Hak
    • The korean journal of orthodontics
    • /
    • v.34 no.2 s.103
    • /
    • pp.165-175
    • /
    • 2004
  • Information on the limits of treatment could allow for more rational treatment Planning and better results after treatment. From this point of view, this article has attempted to discuss the limits of orthodontic tooth movement. A relatively wider range of tooth movement is expected after Class III surgical-orthodontics than after conventional orthodontic treatment in general. The purposes of this Paper were: first, to evaluate the reliability of teeth position measuring gauge; and second, to elucidate the limits of orthodontic tooth movement. Dental casts of fifty-fine subjects were analyzed by using Set-up model checker (InVisitec Co., Korea) before and aster the Class III surgical-orthodontic treatment. The changes of maxillary and mandibular dental arch widths were also measured from the canines to the second molars. To test the inter-examiner reliability, randomly selected casts were measured by another examiner. Descriptive statistics and paired t tests were used to explain the tooth movement during treatment. The results showed a relatively good reliability of measuring instruments and a very diverse range of tooth movement. Collective changes by the orthodontic tooth movement evaluated in Class III surgical-orthodontics allowed for a suggestive interpretation of specific treatment patterns. Arch width changes during the inter-arch coordination were mainly the result of tipping in both buccal segments. Based on the results of this study, the possibility of a change in dentition as a result of orthodontic treatment should be understood in order to launch a well-organized plan of treatment.

Changes in the Titer of Tooth Root Antibodies Accompanying Root Resorption Associated with Orthodontic Tooth Movement (치아이동시 치근 흡수에 따른 치근항체의 역가 변화)

  • Park, Soo-Byung;Son, Woo-Sung
    • The korean journal of orthodontics
    • /
    • v.24 no.2
    • /
    • pp.303-317
    • /
    • 1994
  • This study was designed to measure the changes in the titer of tooth root antibodies accompanying root resorption associated with orthodontic tooth movement in dogs to explore a role of the specific immune response in root resorption during orthodontic tooth movement. Five adult mongrel dogs, 2 years of age, were used in the study. Six lower incisors were extracted as sources of homologous antigen in the dogs. Tooth root antigen preparations were made from a 6M Guanidine-HCl-10% EDTA(pH5.0) extract of these root dentins. Root resorption was elicited by intrusion of six maxillary incisors with 200-250gm intrusive force. In 9th week, resorbing six maxillary anterior teeth were extracted. Serum samples were taken from each dog prior to intrusion and weekly for 11 consecutive weeks. Serum autoantibody titers were determined with an enzyme-linked immunosorbent assay. As controls for antibody specificity, sera which were previously incubated with tooth root antigen as well as sera to an unrelated bacterial antigen (Porphyromonas gingivalis 33277) for 3 hours at 25 were measured in all runs. Root resorption was monitored monthly using occlusal radiographs. And then root resorption patterns were observed with a zoom stereo microscope (Model SZH-121, Olympus optical Co. Ltd.). Incisors did not show clear radiographic evidence of significant and progressive root resorption, but periodontal ligament space had widened. But root resorption was observed on the apical regions of the maxillary incisors with a zoom stereo microscope. Teeth showed the shallow depression generally accompanying deep resorption. These demonstrate a slight tendency for an immediate decrease followed by rebound to levels above the pre-treatment baseline. A peak titer of autoantibody to dentin antigen occurred on day 28, then steadily decreased during the 9th week period as the roots resorbed and then rapidly spiked in animals when the resorbing teeth were extracted. When sera is incubated with tooth root antigen, serum activity in the ELISA was almost absent. This is because serum activity in the ELISA could be removed by absorption of the serum with dog dentin antigen. Serum ELISA activity to the unrelated bacterial antigen remained essentially unchanged in all animals throughout the experimental period. When the time course of changes in autoantibody to homologous tooth root antigen prepatration and unrelated bacterial antigen was compared, no significant differences were found(${\alpha}=0.05$). In general, the overall pattern of changes in autoantibody was similar to the two antigens. These findings suggest the possibility that these immunologic changes precede a significant development of root resorption lesions rather than merely reflecting their presence. Therefore, this suggests that the changes of antibody levels may have some predictive value for root resorption.

  • PDF

THE EFFECT OF LOW DIETARY CALCIUM AND IRRADIATION ON MANDIBLE IN RATS (저칼슘식이와 방사선조사가 백서 악골에 미치는 영향의 실험적 연구)

  • Lee Sun-Ki;Lee Sang-Rae
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
    • /
    • v.23 no.2
    • /
    • pp.229-250
    • /
    • 1993
  • This study was performed to investigate the morphological and structural changes of bone tissues and the effects of irradiation on the mandibular bodies of rats which were fed low calcium diets. In order to carry out this experiment, 160 seven-week old Sprague-Dawley strain rats weighing about 150 gm were selected and equally divided into one normal diet group of 80 rats and one low calcium diet group with the remainder. These groups were then subdivided into two groups, 40 were assigned rats for each subdivided group, exposed to radiation. The Group 1 was composed of forty non-irradiated rats with normal diet, Group 2 of forty irradiated rats with normal diet, Group 3 forty non-irradiated rats with low calcium diet, and Group 4 forty irradiated rats with low calcium diet. The two irradiation groups received a single dose of 20 Gy on the jaw area only and irradiated with a cobalt-50 teletherapy unit. The rats with normal and low calcium diet groups were serially terminated by ten on the 3rd, the 7th, the 14th, and the 21st day after irradiation. After termination, both sides of the dead rats mandible were removed and fixed with 10% neutral formalin. The bone density of mandibular body was measured by use of bone mineral densitometer(Model DPX -alpha, Lunar Corp., U.SA). Triga Mark ill nuclear reactor in Korea Atomic Research Institute was used for neutron activation and then calcium contents of mandibular body were measured by using a 4096 multichannel analyzer (EG and G ORTEC 919 MCA, U.SA). Also the mandibular body was radiographed with a soft X-ray apparatus(Hitex Co., Ltd., Japan). Thereafter, the obtained microradiograms were observed by a light microscope and were used for the morphometric analysis using a image analyzer(Leco 2001 System, Leco Co., Canada). The morphometric analysis was performed for parameters such as the total area, the bone area, the inner and outer perimeters of the bone. The obtained results were as follows: 1. In the morphometric analysis, total area and outer perimeter of the mandibular bodies of Group 3 were a little smaller than that of Group 1. The mean bone width and bone area were much smaller than that of Group 1 and the inner perimeter of Group 3 was much longer than that of Group 1. The total area and outer perimeter of Group 2 and Group 4 showed little difference. The mean bone width and bone area of Group 4 were smaller than that of Group 2 and the inner perimeter of Group 4 was longer than that of Group 2. 2. The remarkable decreases of the number and thickness of trabeculae and also the resorption of endosteal surface of cortical bone could be seen in the microradiogram of Group 3, Group 4 since the 3rd day of experiment. On the 21st day of experiment, the above findings could be more clearly seen in Group 4 than in Group 3. 3. The bone mineral density of Group 3 was lesser than that of Group 1 and the bone mineral density of Group 4 was lesser than that of Group 2 on the 7th, 14th, 21st days. The irradiation caused the bone mineral density to be decreased regardless of diet. In the case of Groups with low calcium diet, the bone mineral density was much decreased on the 21st day than on the 3rd day of experiment. 4. The calcium content in mandible of Group 3 was smaller than that of Group 1 throughout the experiment. roup 4 showed the least amount of calcium content. The irradiation caused the calcium content to be decreased regardless of diet. In the case of Groups with low calcium diet, the calcium content was much decreased on the 21st day than on the 3rd day of experiment. In conclusion, the present study demonstrated that morphological changs and decrease of bone mass due to resorption of bone by low calcium diet, and that the resorption of bone could be found in the spongeous bone and endosteal surface of cortical bone. So the problem of resorption of bone must be considered when the old and the postmenopausal women are taken radiotherapy because the irradiation seems to be accelerated the resorption of osteoporotic bone.

  • PDF

Study on Effect of Saengbal-eum-II(Shēngfà-yĭn-II)on Hair Regrowth Promotion in C57BL/6 Mice (생발음(生髮飮)-II 피부도포가 C57BL/6 마우스의 육모촉진에 미치는 효과)

  • Han, Ae-Ri;Sohn, Nak-Won;Chung, Seok-Hee;Kim, Sung-Su;Song, Mi-Yeon
    • Journal of Korean Medicine Rehabilitation
    • /
    • v.19 no.4
    • /
    • pp.95-113
    • /
    • 2009
  • Objectives : Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) is a hair care product which is composed of ten plant extracts used in oriental medicine. This study was carried out to investigate the effects of Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) on hair regrowth and cytokine changes in a shaving model of C57BL/6 mice. Materials and Methods : Five-week-old mice were acclimated for 1 week at a temperature between $21-23^{\circ}C$, 40-60% relative humidity, and 12h of a light/dark cycle before beginning of the experiment. There were three experimental groups including 50% ethanol (EtOH, control), a positive control of 3% Minoxidil, and 30% Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) in 50% ethanol in 18 female mice. The test compounds were topically treated once a day over 12 days. The hair regrowth was photographically and histologically determined during the experimental period of 12 days. Revelation of EGF, $TGF-{\beta}1$ and IL-6 in hair follicle were also determined using immunohistochemistry. In addition to that, IL-6, $TNF-{\alpha}$, and $IL-1{\beta}$ in skin tissue were determined using enzyme-linked immunosorbent assay(ELISA). Results : Hair regrowth in 3% Minoxidil and Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) groups was promoted earlier and faster than the control group. Concentrations of hairs and thick-hair ratio in 3% Minoxidil and Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) groups were promoted than the control group. EGF was moderately positive in hair follicle of 3% Minoxidil and Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) groups, but negative in the control group. $TGF-{\beta}1$ was not significantly difference between the groups. IL-6 in hair follicle of Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) group was negative, but weakly positive in 3% Minoxidil and control group. IL-6 and $IL-1{\beta}$ in skin tissue were significantly decreased in Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) group, but there was not significantly decreased in 3% Minoxidil and control group. $TNF-{\alpha}$ in skin tissue was significantly decreased in 3% Minoxidil and Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) groups. Conclusions : These results suggest that Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) has hair growth promoting activity and it can be used for treatment of alopecia. And these effects relate to EGF revelation of hair follicle and a decrease IL-6, $TNF-{\alpha}$, and $IL-1{\beta}$ in skin tissue.

Time Series Analysis on Outcomes of Tuberculosis Control and Prevention Program between Small Areas in Korea - with Patient Registry Data of 234 City.County.District Public Health Centers - (소규모 지역간 결핵관리사업 성과에 대한 시계열분석 - 전국 234개 시.군.구 보건소의 환자등록자료를 중심으로 -)

  • Kim, Chun-Bae;Choe, Heon;Shin, Kye-Chul;Park, Jong-Ku;Ham, Soo-Keun;Kim, Eun-Mi
    • Tuberculosis and Respiratory Diseases
    • /
    • v.48 no.6
    • /
    • pp.837-852
    • /
    • 2000
  • Backgrounds : Today, tuberculosis cannot only be cured medically, but also controlled by public health. Despite the overall worldwide decline in tuberculosis, the disease continues to be a significant problem among developing countries and in the slums of large cities in some industrialized countries. Particularly, this communicable disease has come into the public health spotlight because of its resurgence in the 1990's. our country has been operating the Korean National Tuberculosis Control Program since 1962, focusing around public health centers. Therefore, this study aims to compare the effectiveness of tuberculosis control activities, one of the major public health activities in Korea, by producing indexes, such as the yearly registration rate per 100,000 population and treatment compliance of tuberculosis on in small areas (communities). Methods : This work was accomplished by constructing a time-series analytic model using data from "1980~2000: the Yearly Statistical Report" with patient registry data of 234 City. County. District public health centers and by identifying the factors influencing the tuberculosis indexes. Results : The trends of pulmonary tuberculosis positive point prevalence and pulmonary tuberculosis negative point prevalence on X-ray screening have declined steadily, beginning in 1981 and continuing to 1998 by region (city, county, district). Although the tuberculosis mortality rate steadily shows a declining trend by year and region, but Korea still ranks first among 29 OECD countries in 1998, with a tuberculosis mortality rate of 7.1 per 100,000 persons, according to the time-series analysis for fatal diseases. Conclusion : The results of the study will form the fundamental basis of future regional health care planning and the Korean Tuberculosis Surveillance System on 2000. Since the implementation of local autonomy through the Local Health Act of 1995, it has now become vita1 for each city, county, district public health centers to determine its own priorities for relevant health care management, including budget allocation and program goals.

  • PDF

Effects of high dose of dexamethasone on $PLA_2$, GGT activity and lung morphology in NNNMU-induced ARDS rats (NNNMU로 유도된 급성호흡곤란증후군 흰쥐 폐장에서의 dexamethasone에 의한 $PLA_2$, GGT의 활성도 및 형태학적인 변화)

  • Lee, Young Man;Park, Yoon Yub;Koh, Younsuck
    • Tuberculosis and Respiratory Diseases
    • /
    • v.43 no.6
    • /
    • pp.925-935
    • /
    • 1996
  • Background : In order to elucidate one of the pathogenic mechanisms of ARDS associated with pulmonary surfactant and oxidant injury, acute lung injury was induced by N-nitroso N-methylurethane (NNNMU). In this model, the role of phospholipase $A_2$ ($PLA_2$), surfactant, gamma glutamyl transferase (GGT) and morphology were investigated to delineate one of the pathogenic mechanisms of ARDS by inhibition of $PLA_2$ with high dose of dexamethasone. Method: Acute lung injury was induced in Sprague-Dawley rats by NNNMU which is known to induce acute lung injury in experimental animals. To know the function of the alveolar type II cells, GGT activity in the lung and bronchoalveolar lavage was measured. Surfactant phospholipid was measured also. $PLA_2$ activity was measured to know the role of $PLA_2$ in ARDS. Morphological study was performed to know the effect of $PLA_2$ inhibition on the ultrastructure of the lung by high dose of dexamethasone. Results : Six days after NNNMU treatment (4 mg/kg), conspicuous pulmonary edema was induced and the secretion of pulmonary surfactant was decreased significantly. In the acutely injured rats' lung massive infiltration of leukocytes was observed. At the same time rats given NNNMU had increased $PLA_2$ and GGT activity tremendously. Morphological study revealed bizarre shaped alveolar type II cells and hypertrophied lamellar bodies in the cytoplasm of the alveolar type II cells. But after dexamethasone treatment (20 mg/kg, for six days) in NNNMU-treated rats, these changes were diminished i.e. there were decrease of pulmonary edema and increase of surfactant secretion from alveolar type D cells. Rats given dexamethasone and NNNMU had decreased $PLA_2$ and GGT activity in comparison to NNNMU induced ARDS rats. Conclusion : Inhibition of $PLA_2$ by high dose of dexamethasone decreased pathological findings caused by infiltration of leukocytes and respiratory burst. Based on these experimental results, it is suggested that an activation of $PLA_2$ is the one of the major factors to evoke the acute lung injury in NNNMU-induced ARDS rats.

  • PDF