• Biomolecules & Therapeutics
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• v.23 no.6
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• pp.510-516
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• 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
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• v.6 no.1
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• pp.1-7
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• 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
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• v.48 no.4
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• pp.37.1-37.17
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• 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
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• v.16 no.2
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• pp.219-225
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• 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
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• v.57 no.3
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• pp.250-256
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• 2004

Background : Bacterial infections in diabetic patients are an important cause of increased morbidity and mortality. It has been reported that bacterial infections in diabetics showed more impaired PMN functions such as reduced PMN respiratory burst and decreased microbicidal activity in inflammed tissues. Also, apoptosis(programmed cell death) is postulated to be a key mechanism for neutrophil elimination. It is very important that PMN apoptosis keeps the balance from an area of inflammation. Actuallly, as little was known about PMN apoptosis and respiratory burst in diabetes, we investigated PMN apoptosis and hydrogen peroxide production after endotoxin exposure. Methods : Peripheral venous blood samples were collected by routine venipuncture from healthy volunteers and diabetics to harvest neutrophils. We respectively measured the PMN apoptosis, the production of hydrogen peroxide, and the cell viability. Results : Normal neutrophils showed a tendency to decreased apoptosis after endotoxin treatment. In patients with diabetes, PMN apoptosis was significantly decreased compared with healthy controls. In addition, the LPS-induced neutrophils in diabetics demonstrated more decreased apoptosis. However, the production of hydrogen peroxide was not different between groups. Conclusion : These observations suggest that the decreased PMN apoptosis in diabetics with endotoxin exposure may also affect the increased susceptibility and severity of infections.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.217-224
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• 2000

Background : It is well known that when macrophages are stimulated with endotoxin, they produce a wide variety of cytokine mediators, including TNF-$\alpha$ and IL-1$\beta$. However, there is an alteration in the macrophages' responsiveness when they are challenged with repeated bouts of endotoxin, termed "endotoxin tolerance" which is regarded as a self-protective phenomenon from continuous stimulation. In this study, endotoxin tolerance in the peripheral blood monocytes of sepsis patients was evaluated. Methods : Fourteen patients with organism-documented sepsis were included. The severity of illness was evaluated by APACHE II score. Peripheral blood monocytes were isolated from the patients and diluted to $1{\times}10^5$ well. After stimulation with endotoxin (LPS of E. coli O114 : B4, 100 ng/ml), they were incubated at $37^{\circ}C$ in 5% $CO_2$ incubator for 24 hours. Supernatant was collected for the measurement of TNF-$\alpha$ and IL-1$\beta$ with ELISA method. Peripheral blood monocytes of seven healthy volunteers were used as control. Results : The APACHE II score (mean$\pm$SD) of the patients at the time of blood sampling was 12.2$\pm$5.7. The primary infection foci were urinary tract infection, pneumonia, subacute bacterial endocarditis, and catheter related infection, etc. The causative organisms were gram negative rods (10 cases), gram positive cocci (6 cases) with two cases of mixed infection. Serum TNF-$\alpha$ could be measured in 4 cases with 29.9$\pm$27.7 pg/ml. Serum IL-1$\beta$was measurable in only one patient. The TNF-$\alpha$ level of supernatant of cultured peripheral blood monocytes was 2,703$\pm$2,066 pg/ml in patients and 2,102$\pm$1914 pg/ml in controls. The IL-1$\beta$level of supernatant was 884$\pm$1,050 pg/ml in patients and 575$\pm$558 pg/ml in controls. There was no difference of TNF-$\alpha$ and IL-1$\beta$ level between patients and controls. Conclusion : We cannot prove the phenomenon of endotoxin tolerance in this study. Future study needs to be focused on the more severe sepsis patients who were taken for sampling earlier. Addition of serum to the culture medium could be an another valuable option for the success of this study.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.2
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• pp.171-180
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• 2024

The endotoxin test is based on the reaction between Limulus Amebocyte Lysate (LAL) and the lipopolysaccharides of Gram-negative bacteria. In this study, we sought to identify factors that interfere with the LAL testing of radiopharmaceuticals and evaluated acceptable ranges. A gel-clot LAL test and a chromogenic LAL test were used as endotoxin tests. We compared the performances of the Endosafe^Ⓡ LAL and recombinant Endosafe^Ⓡ Recombinant Cascade Reagent (rCR) cartridges for the chromogenic test. The factors that interfered with ⁶⁸Ga-DOTATOC injection were pH, 4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid (HEPES) buffer, and organic solvents, especially ethanol. However, interference by these factors was overcome by diluting the ⁶⁸Ga-DOTATOC injection tenfold. In addition, no interference was observed at pH values between 4 and 8, at a HEPES concentration of 2,000 ㎍/mL, or an ethanol concentration of <1%. Furthermore, results showed that interfering factors had similar effects on the performances of the Endosafe^Ⓡ LAL and Endosafe^Ⓡ rCR cartridges. The results of this study are expected to be useful for evaluating factors that interfere with the endotoxin testing of new radiopharmaceuticals.

• IMMUNE NETWORK
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• v.10 no.6
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• pp.230-238
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• 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
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• v.13 no.1_2
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• pp.111-116
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• 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.

• Journal of Korean society of Dental Hygiene
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• v.16 no.2
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• pp.155-163
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• 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.