An Antimicrobial Activity Assessment of Three Endodontic Sealers on Enterococcus faecalis, Candida albicans, and Staphylococcus aureus by a Direct Contact Test: An In Vitro Study

Introduction: For a successful endodontic treatment, antimicrobial property of endodontic filing is mandatory. Hence, the aimof this in vitro study was to assess the antibacterial efficacy of three endodontic sealers on Enterococcus faecalis, Candidaalbicans, and Staphylococcus aureus by direct contact test (DCT).Materials and Methods: The antimicrobial efficacy of three different sealers, AH Plus, mineral trioxide aggregate (MTA)Fillapex, and Endosequence BC was tested against E. faecalis ATCC 29212, C. albicans ATCC 10231 and S. aureus ATCC25923 by DCT. Freshly mixed sealers were placed in flat bottom test tubes incubated at 37°C. Thereafter, 10 μL of suspensionwas drawn and spread over cultural plates to determine the colony count using a digital colony counter. Readings were takenat 1 h (fresh specimen), then at 24 h (after setting). The results were tabulated and statistical analysis was done using oneway ANOVA and Tukey HSD test.Results: DCT showed a significant decrease in microbial count in AH Plus, MTA Fillapex, and Endoseq BC at both the timeintervals. Group 3 (Endosequence BC) showed minimum microbial count followed by Group 2 (MTA Fillapex) and maximumfor Group 1 (AH Plus) for both the time intervals (1 h and 24 h).Conclusion: Endosequence BC showed maximum antimicrobial efficacy against all the tested microorganisms for both thetime intervals, followed by MTA Fillapex and AH Plus.

Research progress of cell co-culture method / 中华危重病急救医学

Cell culture technology is the most commonly used method in the in vitro experiments at present. However, monolayer cell culture technology has been unable to meet the demand of the researchers. This is because that monolayer cell culture cannot mimic the cellular environment in which multiple cells interact with each other in the body. We cannot discuss the relationship of many cells, because we do not know the relationship between cells through a single kind of cell. So cell co-culture medicine arises at the historic moment for the demand. With the development of research method in recent years, cell co-culture method also has been improved in practice: from direct contact co-cultures to indirect contact co-cultures, from two-dimensional co-cultures to three-dimensional co-cultures. Cell co-culture method is closer to the human body. It is also more advantageous to study the interaction among cells. Nowadays, there are more researchers tend to select this method to study the physiological and pathological in vitro model, tissue engineering, and cell differentiation research. At the same time, it has become the focus of drug research and development, drug analysis, mechanism of drug action, and drug targets. This article will review the studies of cell co-culture method, summarize advantages and disadvantages of various methods, so as to promote improvement of cell culture methods, to build cells co-culture system that more close to human body, and build the in vitro model that simulate internal circulation of human body further.

Ebola virus infection / 中国小儿急救医学

Ebola,known as Ebola hemorrhagic fever,is caused by infection with a virus of the fami-ly Filoviridae,genus Ebolavirus. Ebola is circulating in some of the west Africa countries and causing outb-reacks and epidemic with high mortality. The virus can be spread in humans by direct contact with blood or body fruit of infected one through broken skin or mucous membranes. The virus can not be spread by air or water. The symptoms of Ebola include fever,severe headache,muscle pain,weakness,fatigue,diarrhea,vomi-ting,abdominal( stomach) pain and unexplained hemorrhage. Symptoms of Ebola and complications are trea-ted as they appear. Recovery from Ebola depends on good supportive care and the patient′s immune response. Those people recovered from Ebola developed antibodies against Ebola virus and last long period. No ap-proved vaccine or medicine is available for Ebola.

Comparación in vitro de la actividad antimicrobiana de AhPlus, RSA y Ledermix contra Enterococcus faecalis / In vitro comparison of anti-microbial activity of AH Plus, RSA and Ledermix against Enterococcus faecalis

Objetivo: Evaluar in vitro la actividad antimicrobiana de dos selladores endodónticos RSA, AH Plus y de la pasta LedermixN sobre Enterococcus faecalis con tres diferentes técnicas. Método: Prueba de contacto directo. En una superficie de acrílico se colocó el sellador y se inoculó una suspensión de E. faecalis, se dejó en un microtubo con 1mL de caldo BHI, se realizaron diluciones logarítmicas sembrándose en placas de agar sangre para cuantificar las unidades formadoras de colonia. Prueba de dilución. Los selladores y la pasta se colocaron en un cilindro de plástico, la bacteria se inoculó en el caldo de cultivo y se realizó el mismo procedimiento de cuantificación. Prueba de dilución en agar. Se realizaron tres pozos en una placa de agar sangre y se rellenaron con los dos cementos, la pasta de LedermixN se inoculó una suspensión de E. faecalis en la superficie, para evaluar zonas de inhibición de crecimiento. Resultados: La pasta de Lesdermix N tuvo mayor porcentaje de actividad antimicrobiana en la prueba de contacto directo. Ningún cemento ni la pasta presentó actividad antimicrobiana en la prueba de dilución y en la prueba de dilución en agar; en ésta el sellador AH plus y la pasta LedermixN presentaron un halo de hemólisis en las placas de agar sangre. Conclusiones: La técnica de contacto directo es la más adecuada para evaluar el efecto antimicrobiano de los cementos.

Aim: In vitro assessment of antimicrobial activity sustained by two root canal sealers: RSA®, AH Plus® as well as LedermixN® paste upon Enterococcus faecalis using three different techniques. Method: Direct contact test (DCT). Sealers were placed on an acrylic surface. A E. faecalis suspension was inoculated and left in a microtube with 1 mL of BHI broth. Logarithmic dilutions were conducted spreading them in blood agar plates so as to quantify CFU's (colony forming units). Dilution test (DT). Sealers and paste were placed in a plastic cylinder. Bacteriae were inoculated in the culture broth and the same quantification procedure was undertaken. Agar dilution test (ADT). On a blood agar plate three wells were manufactured: they were filled with both cements. On the LedermixN paste surface a E. faecalis suspension was inoculated so as to assess growth inhibition areas. Results: In the Direct contact test, LedermixN paste showed higher antimicrobial activity percentage. Neither of both cements nor the paste presented antimicrobial activity in dilution and Agar dilution test. In the Agar dilution test, AH Plus sealer and LedermixN paste exhibited a hemolysis halo in the blood agar plates. Conclusions: Direct contact test technique was considered the most appropriate to assess antimicrobial effects of cements.

Avaliação in Vitro da atividade antimicrobiana do carvacrol através dos métodos de contato direto e gasoso / Evaluation In vitro of antimicrobial activity of carvacrol by the direct and gaseous contact methods

Nas últimas décadas, a resistência bacteriana frente aos antimicrobianos se constituiu em um sério problema para a saúde pública, impondo barreiras ao controle de diversas espécies de microrganismos. O carvacrol é um composto fenólico geralmenete encontrado como componente majoritário do óleo essencial de algumas plantas como Origanum vulgare (orégano), Lippia graveolens (Lípia) e Lipia sidoides (alecrim-pimenta). Estudos demonstram a atividade antibacteriana do orégano, possivelmente devido ao carvacrol. Para avaliar a ação antimicrobiana desse composto, foram utilizadas linhagens padrão bacterianas (Staphylococcus aureus ATCC25923 e Pseudomonasa aeruginosa ATCC15442) e fúngicas (Candida albicans ICB12, C. krusei ATCC6258 e C. tropicalis ATCC13803). Os métodos de microdiluição em caldo e de contato gasoso foram utilizados para determinar a concentração inibitória mínima (CIM) e a dose inibitória mínima (DIM) respectivamente, bem como a atividade moduladora da ação antibiótica através de ambos os métodos. O carvacrol, combinado em concentrações subinibitórias com as drogas antimicrobianas apresentou resultados relevantes frente às cepas de Staphylococcus aureus e Candida albicans, por tanto este estudo permitiu comprovar a atividade moduladora do carvacrol.

In the last decades, the bacterial resistance to antimicrobials becomes a serious problem of public health, creating several difficulties to control several microrganisms with nosocomial interest. The carvacrol, the main phenol compound of many plants as Origanum vulgare, Lippia graveolens and Lipia sidoides. Studies demonstrated and intensive antibacterial activity of O. vulgare, probably due the carvacrol. To evaluate the antimicrobial activity of this compound, were assayed microbial strains of Staphylococcus aureus ATCC25923, Pseudomonas eruginosa ATCC15442, Candida albicans ICB12, C. krusei ATCC6258 and C. tropicalis ATCC 13803. Using the microdilution and the gaseous contact method, were determined the minimum inhibitory concentration (MIC) and the minimum inhibitory dose (DIM), respectively as well as the modulatory activity with both methods. The carvacrol, used in subinhibitory concentrations associated with antimicrobial drugs demonstrated an interesting modulatory activity against Staphylococcus aureus and Candida albicans strains, indicating the antimicrobial and modulatory activity of this compound.

The First Case of Human Brucellosis in Korea / 감염과화학요법

Brucellosis is usually transmitted to human by direct contact with infected animals or by ingestion of unpasteurized dairy products. Because of the wide spectrum of its clinical manifestations, brucellosis may appear as other infections and asymptomatic conditions and, therefore, the diagnosis of the disease is frequently missed or delayed. A 41-years-old livestock worker was attended at a local clinic with headache, undulating fever, fatigue, weight loss presentations but the symptoms were not improved in spite of symptomatic therapy of the disease for 6 weeks. Epidemiological background showed that the patient had often ingested unpasteurized cow milk. We confirmed Brucella abortus infection by STA, ELISA and PCR methods. Symptomatic therapy of the disease with appropriate antibiotics (streptomycin, doxicyclin), had favourable outcome. It's the first case report of human brucellosis caused by direct contact of brucella infected milk cow or ingestion of raw milk in Korea, since its original identification in 1939.

The First Case of Human Brucellosis in Korea / 감염과화학요법

Brucellosis is usually transmitted to human by direct contact with infected animals or by ingestion of unpasteurized dairy products. Because of the wide spectrum of its clinical manifestations, brucellosis may appear as other infections and asymptomatic conditions and, therefore, the diagnosis of the disease is frequently missed or delayed. A 41-years-old livestock worker was attended at a local clinic with headache, undulating fever, fatigue, weight loss presentations but the symptoms were not improved in spite of symptomatic therapy of the disease for 6 weeks. Epidemiological background showed that the patient had often ingested unpasteurized cow milk. We confirmed Brucella abortus infection by STA, ELISA and PCR methods. Symptomatic therapy of the disease with appropriate antibiotics (streptomycin, doxicyclin), had favourable outcome. It's the first case report of human brucellosis caused by direct contact of brucella infected milk cow or ingestion of raw milk in Korea, since its original identification in 1939.

Evaluation of the Cytotoxicity of Polyetherurethane (PU) Film Containing Zinc Diethyldithiocarbamate (ZDEC) on Various Cell Lines

A polyetherurethane (PU) film containing 0.1% zinc diethyldithiocarbamate (ZDEC) is the international standard reference material for testing the in vitro cytotoxicity of polymer based biomaterials. Nowadays, culturing L929 or BALB/3T3 cells in direct contact or in an extract dilution condition is the most frequently using method for evaluating the cytotoxicity from biomaterials and medical devices. However, the results often vary, because it is directly related to the cellular functions and the mechanism of the toxicity of the contacting cells. In this study, 13 cell lines originating from various tissues were used to detect the cytotoxic activities of a PU film containing 0.1% ZDEC (PU-ZDEC). The correlation between the reactivity zone size and the relative cytotoxicity by quantifying the released total protein from each cell in the direct contact testing method was investigated. Hepa-1c1c7 cells demonstrated the highest sensitivity in the reactivity zone size, while CHO/dhFr(-) cells were the most sensitive in terms of the relative cytotoxicity. A correlation between the two processes in each cell line was not found (r=-0.478). In the extract dilution method, which involved cultivating the cells in the medium with various ZDEC concentrations prepared by diluting the PU incubation, the cytotoxicity increased with increasing ZDEC concentration in all cell lines. The BALB/ 3T3 cells demonstrated the highest sensitivity in the extract dilution method. No correlation in a comparison of the relative cytotoxicity from the direct contact method with the extract dilution method in each cell line, was found (r=-0.445). In this experiment, Hepa-1c1c7, BALB/3T3, CHO/dhFr(-) and L-929 cells among the 13 types of cell lines were the sensitive cell lines according to the two methods. The preliminary results suggest that a comparison of at least one or more cytotoxicity testing methods and many cell lines is necessary for an in vitro cytotoxicity test of biomaterials.