• Biomolecules & Therapeutics
• /
• 제23권6호
• /
• pp.510-516
• /
• 2015

In this review, lipid A, from its discovery to recent findings, is presented as a drug target and therapeutic molecule. First, the biosynthetic pathway for lipid A, the Raetz pathway, serves as a good drug target for antibiotic development. Several assay methods used to screen for inhibitors of lipid A synthesis will be presented, and some of the promising lead compounds will be described. Second, utilization of lipid A biosynthetic pathways by various bacterial species can generate modified lipid A molecules with therapeutic value.

• Applied Microscopy
• /
• 제6권1호
• /
• pp.1-7
• /
• 1976

To investigate the nature of typhoid cells, three cases of clinically, serologically and histopathologically proven typhoid lesions of the small intestine and regional lymph nodes were studied light and electron microscopically, Light microscopically, typhoid cells were swollen mononuclear cells characterized by abundant amount of eosinophilic cytoplasm and frequent phagocytoses of red blood cells, bacterial clumps and other tissue debris. These cells were pyronin negative, Electron microscopically, these cells showed marked and diffuse dilatation of RER cisternae and disappearance of ordinary cytoplasmic organelles, but frequent phagocytosed materials, The meaning and reason of RER cisternal dilatation and reduction of cytoplasmic organelles were discussed, and are regarded as degenerative process due to bacterial endotoxin. Although there was hot enough cytoplasmic organelles to pinpoint the origin of typhoid cells, active phagocytosis and evidences against being either plasmacytic or lymphocytic nature favored retuculoendothelial nature of the typhoid cells.

• Restorative Dentistry and Endodontics
• /
• 제48권4호
• /
• pp.37.1-37.17
• /
• 2023

This study aimed to compare the disinfectant ability of chlorhexidine (CHX) gel and sodium hypochlorite (NaOCl). Systematic searches were conducted from inception until December 8th, 2022 (MEDLINE/PubMed, Cochrane Library, Web of Science, Scopus, Embase, and Grey Literature databases). Only randomized clinical trials were included. The revised Cochrane risk of bias tools for randomized trials were used to assess the quality of studies. Meta-analyses were performed. The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation tool. Six studies were included. Five had a low risk of bias and 1 had some concerns. Three studies assessed bacterial reduction. Two were included in the meta-analysis for bacterial reduction (mean difference, 75.03 [confidence interval, CI, -271.15, 421.22], p = 0.67; I² = 74%); and 3 in the meta-analysis for cultivable bacteria after chemomechanical preparation (odds ratio, 1.03 [CI, 0.20, 5.31], P = 0.98; I² = 49%). Five studies assessed endotoxin reduction. Three were included in a meta-analysis (mean difference, 20.59 [CI, -36.41, 77.59], p = 0.48; I² = 74%). There seems to be no difference in the disinfectant ability of CHX gel and NaOCl, but further research is necessary.

• Journal of Microbiology and Biotechnology
• /
• 제16권2호
• /
• pp.219-225
• /
• 2006

The rabbit pyrogen test and Limulus amoebocyte lysate (LAL) assay have been used to detect endotoxins present in vaccines. Currently, the rabbit pyrogen test is used to detect endotoxins in hepatitis B (HB) vaccines, even though the HB surface protein, which is the active ingredient, is overexpressed in and purified from eukaryotic cells that lack these endotoxins. Although the LAL clot assay is sensitive and reliable and can be used to replace the rabbit pyrogen test, its reaction is limited by the lack of responsiveness to the Gram-positive bacterial components. Furthermore, aluminum hydroxide in the HB vaccine can interfere with the LAL assay. In contrast, macrophages can detect the endotoxin as well as other pyrogens, and secrete $TNF-{\alpha}$. Therefore, this study was undertaken to examine the possibility of replacing the animal tests with a more efficient $TNF-{\alpha}$ secretion assay. With this in mind, we determined if aluminum hydroxide in the HB vaccines affects the $TNF-{\alpha}$ secretion assay. HB vaccines and the HB protein solutions spiked with lipopolysaccharide (LPS) produced the same level of dose-dependent $TNF{\alpha}$ secretion and temperature increase in rabbits, indicating that aluminum hydroxide in the HB vaccine does not interfere with the pyrogenic response in rabbits, nor does it interfere with $TNF-{\alpha}$ secretion. In addition, the $TNF-{\alpha}$ assay was found to be more sensitive than the LAL assay, and correlated well with the pyrogen test and the LAL assay. These results suggest that the $TNF-{\alpha}$ assay in RAW264.7 cells is a good substitute for the current pyrogen assays that are used for detecting LPS in HB vaccines as well as in other vaccines containing aluminum.

• Tuberculosis and Respiratory Diseases
• /
• 제57권3호
• /
• pp.250-256
• /
• 2004

배 경 : 세균 감염 시 이환율과 사망률이 증가한다고 알려져 있는 당뇨에서 염증 조직 내 활성 산소 기능과 세균능 감소를 보이는 중성구의 기능 이상이 잘 알려져 있다. 또한, 기획성 세포사멸이 중성구 제거에 중요한 역할을 한다고 알려져 있다. 중성구의 기획성 세포사멸은 염증 조직 내I 균형을 유지하는 데 중요하다. 실제 당뇨병에서 중성구의 기획성 세포사멸과 활성 산소에 대한 연구가 없는 실정으로 본 연구를 통해 당뇨에서 내독소 투여시 중성구의 기획성 세포사멸과 과산화수소 분비능을 알고자 하였다. 방 법 : 정상과 당뇨 환자의 전혈을 뽑아 중성구 만을 추출하여 내독소에 노출시킨 후 중성구의 기획성 세포사멸, 과산화수소 분비능, 생존율을 각각 측정하였다. 결 과 : 정상 중성구는 내독소 투여 후 기획성 세포사멸이 감소하는 경향을 보였다. 정상과 비교할 때 당뇨환자의 중성구는 기획성 세포사멸이 감소하였고 특히 내 독소를 투여한 군에서 더욱 감소하였다. 과산화수소 분비능의 차이는 보이지 않았다. 결 론 : 본 연구를 통해 당뇨환자에서 내독소 투여로 인한 중성구의 기획성 세포사멸 감소가 당뇨에서 중증 감염과 높은 사망률에 영향을 줄 것으로 사료된다.

• Tuberculosis and Respiratory Diseases
• /
• 제49권2호
• /
• pp.217-224
• /
• 2000

패혈증에서는 지속적인 내독소 자극에 의해 염증 반응이 계속 유발될 수 있으나, 염증반응에 주도적인 역할을 하는 말초혈액 단핵구는 반응도를 스스로 낮춤으로서 염증 반응을 감소시키는 경향을 보이는데, 이러한 현상을 내독소 내성(endotoxin tolerance)라고 한다. 내독소 내성은 과다한 염증반응에 대한 자체의 방어작용으로 이해되고 있다. 본 연구에서는 조직액에서 감염균이 증명된 패혈증 환자를 대상에서 추출한 말초 혈액 단핵구에서 내독소 내성의 현상을 관찰하고자 하였다. 방법 : American College of Chest Physician-Society의 Critical Care Medicine Consensus Conference에서 정한 sepsis의 기준을 만족하고, 감염균이 확인된 14명의 환자를 대상으로 하였으며 질환의 중증도는 APACHE II score를 이용하여 평가하였다. 대상환자의 혈청에서 TNT-$\alpha$와 IL-1$\beta$의 농도를 측정한 뒤, 말초혈액 단핵구를 추출, 배양하여, 내독소(100 ng/ml)로 자극하였다. 내독소 자극 후 24시간 뒤에 배양 상층액에서 ELISA 방법으로 TNT-$\alpha$와 IL-1$\beta$의 농도를 측정하였다. 결과 : 대상 환자는 총 14명(남자 : 8 명, 여자 6명)으로 APACHE II score는 12.2$\pm$5.7 이었다. 감염의 원발 부위는 뇨관감염, 폐렴, 아급성심내막염, 도관감염, 급성담관염 등이었다. 감염 원인균은 그람음성 간균 10례, 그람 양성균 6례였고, 이 중에는 복합감염이 2례가 있었다. 환자군의 혈청 TNF-$\alpha$는 4명에서 측정이 기능했고 평균치는 29.7$\pm$527.7 pg/ml 이었다. IL-1$\beta$는 1명에서 측정가능했고 측정치는 16.1 pg/ml 이었다. 내독소 자극 후 말초혈액 단핵구 배양 상층액의 TNF-$\alpha$농도는 패혈증 환자는 2,703$\pm$2,066 pg/ml, 대조군은 2,101$\pm$1914 pg/ml 이었고, IL-1$\beta$ 농도는 환자군은 884$\pm$1,050 pg/ml, 대조군은 575$\pm$558 pg/ml으로 두 군 사이에 의미있는 차이는 없었다. 결론 : 본 연구에서는 예상과는 달리 패혈증 환자의 말초혈액 단핵구에서 내독소내성을 관찰할 수 없었다. 향후 보다 중증의 환자를 대상으로 하고, 조기에 혈액을 채취하며, 말초혈액 상층액에 혈청을 추가하는 등의 보완을 통하여 재평가가 필요할 것으로 판단된다.

• IMMUNE NETWORK
• /
• 제10권6호
• /
• pp.230-238
• /
• 2010

Background: The MK1 strain, a novel bacterial isolate from soft-rotten tissue of the Neungee mushroom, produces copious amounts of exopolysaccharide (EPS) in a dextrose minimal medium. This study examined the molecular characteristics and immunomodulatory activity of MK1 EPS. Methods: The EPS in the culture supernatant was purified by cold ethanol precipitation, and characterized by SDS- PAGE/silver staining and Bio-HPLC. The immunomodulatory activities of the EPS were examined using the mouse monocytic cell line, RAW 264.7 cells. Results: The molecular weights of the purified EPS were rather heterogeneous, ranging from 10.6 to 55 kDa. The EPS was composed of glucose, rhamnose, mannose, galactose, and glucosamine at an approximate molar ratio of 1.00 : 0.8 : 0.71 : 0.29 : 0.21. EPS activated the RAW cells to produce cytokines, such as TNF-${\alpha}$ and IL-$1{\beta}$, and nitric oxide (NO). EPS also induced the expression of co-stimulatory molecules, such as B7-1, B7-2 and ICAM-1, and increased the phagocytic activity. The macrophage-activating activity of EPS was not due to endotoxin contamination because the treatment of EPS with polymyin B did not reduce the macrophage-activating activity. Conclusion: The EPS produced from the MK1 strain exerts macrophage-activating activity.

• Toxicological Research
• /
• 제13권1_2호
• /
• pp.111-116
• /
• 1997

In the present study, we investigated the neutralization activity of various antimicrobials against lipopolysaccharide (LPS) as well as interaction between two antimicrobials (enrofioxacin and coilstin) using checkerboard method. The neutralization activity of antimicrobials used in the test was assayed by means of LAL chromogenic test after reaction of LPS with colistin, enorfioxacin, ampicillin, polymyxin B, oxytetracycline, streptomycin, and erythromycin. As the results, the neutralization activity of coltstin and polymixin B had a more stronger than that of tested other antimicrobials. In bacterial culture broth, the best neutralization activity of the antibiotics was also shown to coltstin and polymixin B. Meanwhile, It was shown to have synergism between enorfloxacin and coltstin on the basts of FIC (fractional inhibition concentration). The FIC of enorfioxacin-colistin combinations was 0.50-1.03 to Staphylococcus aureus R-209, 1.03-1.06 to Salmonella typhimurium, 0.75-1.25 to Bordetella Bronchtseptica and 1.02-1.25 to E. coli K88ab. On the basts of the above results, the present study may be of clinical usefulness in the choice of an antibiotic therapy for severe sepsts in animals.

• 한국치위생학회지
• /
• 제16권2호
• /
• pp.155-163
• /
• 2016

The purpose of the review article is to investigate the influence of periodontal diseases on preterm birth(PTB) and low birth weight(LBW). PTB and LBW are the main risk factors of infant mortality and a major public health problem. PTB is defined as delivery at less than 37 weeks and LBW is less than 2,500 grams. Over Approximately 60 percent of perinatal mortality results from PTB or LBW. Although the causes of PTB and LBW are not fully understood, infection is the leading cause of PTB and LBW. Periodontal diseases are serious disease burdens because they are caused by bacterial endotoxin, inflammatory reaction, and cytokine. The periodontal diseases are the predisposing factors of cerebrovascular and cardiovascular diseases including atherosclerosis. Over the past 15 years, previous studies revealed that periodontitis had adverse outcomes including PTB and LBW in pregnancy.

• 한국어병학회지
• /
• 제18권3호
• /
• pp.287-292
• /
• 2005

In the present study, immune gene expression of rainbow trout, Oncorhynchus mykiss, against bacterial endotoxin (LPS) was studied in vivo. The expression of prointflammatory cytokine genes (IL-1$\beta$ and TNF-$\alpha$) and IFN-related genes (IRF-I, Mx-3) at gill was assessed by RT-PCR at different time point of day1 and day 3 post-injection. It was shown that the proinflammatory cytokine gene expression at gill was induced 1 day after LPS injection but the expression was not sustained until day 3. Meanwhile upregulated expression of IFN-related genes was found to be only at day 3 post injection, indicating indirect effect of LPS on these genes.