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        검색결과 155

        87.
        2004.12 구독 인증기관 무료, 개인회원 유료
        The inhibitory effects of water extract of Cortex Mori(CM) was investigated for allergic asthma in a mouse model. Experimental allergic asthma was induced by repeated intraperitoneal sensitization and aerosol challenge of ovalbumin (OVA). CM extract (10mg/mouse/day) was administrated orally whereas control mice were given with identical volume of phosphate-buffered saline (PBS) for 7 days during the course of challenge. When airway hyperreactivity(AHR) measured by β-methacoline-induced airflow obstruction was compared, AHR of CM-treated mice was significantly lower than those of control mice, indicating that CM extract can attenuate an asthmatic symptom. Airway recruitment of leukocytes and cytokine levels in broncho-alveolar lavage fluid (BALF) was analyzed in order to evaluate CM effect on pulmonary inflammation. Total number of leukocytes in BALF was lower in CM-treated mice than in control without significance. Interestingly, CM treatment elevated a distribution of eosinophils which are crucial in asthmatic response. However, comparison of absolute number showed that it resulted from a decrease of total leukocyte and macrophage numbers. Levels of type 2 (Th2) cytokines (IL4, IL5 and IL 13) measured by ELISA in BALF were not significantly reduced by CM and IFN-γ, a type 1 (Th1) cytokine, was also comparable between two groups, indicating that CM treatment has little or no effect on airway inflammation and secretion of relevant cytokines. For an insight into the mechanism of CM effect on AHR, immunemodulatory activity of CM was analyzed at a cellular level. Peribronchial lymph node(LN) cells and lung-infiltrating lymphocytes (LIL) collected from CM-treated and control mice were in vitro stimulated with OVA antigen. Although there was no significance, number of LN cell and LIL was higher in CM-treated mice than controls and their Ag-specific proliferative response (3H-TdR uptake assay) was similar. Production of Th2 cytokine, IL 5 and IL 13 was relatively enhanced, but without statistical significance, while IFN-γ production was minimally altered in CM-treated mice. Immunemodulation of CM in the field of humoral immunity, antibody levels in serum were measured and compared. No significant difference was observed in the levels of IgE. However, levels of type 1 and 2 antibody IgG2a and IgG1 were signifcantly enhanced by CM treatment. As CM-mediated alleviation of AHR was not clearly explained by above results, degranulation of eosinophils was finally examined by their release of peroxidase. Levels of peroxidase in BALF was significantly lower in CM treated mice, suggesting that CM inhibits in vivo degranulation of eosinophils, although its effect was not shown during their in vitro incubation. Taken together, data from current study indicate CM extract alleviates AHR through inhibition of eosinophil degranulation rather than any immunological regulation. Instead, immunemodulatory activity of CM is likely to be adversely effective in (Th2)
        5,700원
        88.
        2004.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        연구의 궁극적 목적을 두었다. 일반 사육환경에서 나타날 수 있는 발육온도(20, 25, 3)와 최종령 초기 유충 체중 변이(412.6-1,616.0 mg)는 누에의 용화 결정에 영향을 주지 많았다 한편 유약호르몬(juvenile hormone:計I)동력제인 피리프록시팬(pyriproxyfen)은 10-s M의 낮은 농도에서도 난포세포 개방화를 유도하여, 이 약제가 누에에서도 동력제라는 것을 확인하였다. 피리프록시펜은 약제 농도 및 처리 시기별로 특이하게 누에 미화용 유발 효과를 보였다. 피리프록시펜은 JH 에스테라제(JH esterase: JHE)를 직접적으로 억제하지 못하고, 오히려 활성을 증가시키는 것으로 나타났으며, JH 결합단백질(JH binding protein:JHBP)의 유전자 발현을 억제하는 것으로 나타났다. 즉, 피리프록시펜은 체내에 JH 동력제로 작용하면서 JHE 유전자 활성을 제고시켰지만, JHE활성 증가에 따른 체내 JH함량이 줄어듬에 따라 JHBP의 유전자 활성을 억제하는 것으로 해석된다. 양잠농가 주변으로 살포 가능성이 있는 농약을 대상으로 난포세포 개방화 분석을 실시 한 결과, 제초제 3종(simazine, molinate, alachlor)이 JH 동력제 효과를 가지고 있는 것으로 나타났다. 누에 미화용 원인체 규명을 위해서 이들에 대한 직접 노출 시험이 요구된다.
        4,200원
        100.
        2002.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        누에(Bombyx mori) 5령 유충에서 무름병 증상이 발견되었다. 세균성 병원균이 감염 누에 혈액에서 분리되었고, 본 연구에서 동정되었다. 분리된 세균을 각각의 누에 5령 유충에 cfu(colony-forming unit) 농도로 혈강 주사되었을 때, 뚜렷한 무름병 증상을 유발시켰다. 이렇게 감염된 유충들은 접종 6일 후부터 죽기 시작하여, 10일 경과 후 처리된 유충 모두 사망하였다. Bergey의 세균동정집에 기록된 형태적 및 생리적 형질을 기준으로 이 곤충병원세균이 Staphylo-coccue gallinarum으로 판명되었다. 이 판정은 탄소원 분석 미생물동정장치() 분석 결과와 16S-23S rDNA internal transcribed space 구조에 의해서 확인되었다. 이 세균이 발휘하는 살충기작의 일환으로서, 감염 후 누에 유충 혈구에 세포치사 효과를 주어 패혈증을 유발하는 것으로 분석되었다.
        4,000원
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