Antimicrobial activity of Lactobacillus fermentum TcUESC01 against Streptococcus mutans UA159.

Dental caries is a multifactorial chronic-infection disease, which starts with a bacterial biofilm formation caused mainly by Streptococcus mutans. The use of probiotics has shown numerous health benefits, including in the fight against oral diseases. Strains of Lactobacillus fermentum have already shown probiotic potential against S. mutans, but there are still few studies. Thus, the aim of our study was to evaluate the antimicrobial activity of the inoculum and metabolites produced by L. fermentum TcUESC01 against S. mutans UA159. For this, a growth curve of L. fermentum was performed and both the inoculum and the metabolites formed in the fermentation were tested against the growth of S. mutans UA159 in agar diffusion tests, and only its metabolites were tested to determine the minimum inhibitory concentration, minimal bactericidal concentration and inhibition of cell adhesion. Inhibition of biofilm formation, pH drop and proton permeability were also tested with the metabolites. The zone of inhibition began to be formed at 14 h and continued until 16 h. The inoculum containing L. fermentum also showed zone of inhibition. The MIC for the metabolites was 1280 mg/mL and the MBC was obtained with a concentration higher than the MIC equal to 5120 mg/mL. Half of the MIC concentration (640 mg/mL) was required to inhibit S. mutans adhesion to the surface of the microplates. In the biofilm analyzes, the treatment with the metabolites in the tested concentration was not able to reduce biomass, insoluble glucans and alkali soluble compared to the control biofilm (p > 0.05). The metabolites also did not affect acid production and acid tolerance of S. mutans cells in biofilms compared to saline group (p > 0.05). Lactic acid (50.38%) was the most abundant organic acid produced by L. fermentum. This is the first report showing that the metabolites produced by the Lactobacillus fermentum TcUESC01 have a potential to be used as an antimicrobial agent against S. mutans, showing anti-adherence and bactericidal activity against planktonic cells of S. mutans. Thus, further studies should be carried out in order to better understand the antimicrobial activity of metabolites of L. fermentum TCUESC01.

Anticariogenic activities of Libidibia ferrea, gallic acid and ethyl gallate against Streptococcus mutans in biofilm model.

ETHNOPHARMACOLOGICAL RELEVANCE: In Brazil, ethnopharmacological studies show that Libidibia ferrea (Mart. ex Tul.) L. P. Queiroz is commonly used in folk medicine as an antifungal, antimicrobial and anti-inflammatory. In the Amazon region, the dried fruit powder of L. ferrea are widely used empirically by the population in an alcoholic tincture as an antimicrobial mouthwash in oral infections and the infusion is also recommended for healing oral wounds. However, there are few articles that have evaluated the antimicrobial activity against oral pathogens in a biofilm model, identifying active compounds and mechanisms of action. AIM OF THE STUDY: The aim of this study was to evaluate the antimicrobial and anti-adherence activities of the ethanolic extract, fractions and isolated compounds (gallic acid and ethyl gallate) of the fruit and seed of L. ferrea against Streptococcus mutans. The inhibition of acidicity/acidogenicity and the expression of the S. mutans GTF genes in biofilms were also evaluated. MATERIALS AND METHODS: Minimal Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Inhibitory Concentration of Cell Adhesion (MICA) were evaluated with ethanolic extract (EELF), fractions, gallic acid (GA) and ethyl gallate (EG) against S. mutans. Inhibition of biofilm formation, pH drop and proton permeability tests were conducted with EELF, GA and EG, and also evaluated the expression of the GTF genes in biofilms. The compounds of dichloromethane fraction were identified by GC-MS. RESULTS: This is the first report of shikimic, pyroglutamic, malic and protocatechuic acids identified in L. ferrea. EELF, GA and EG showed MIC at 250 µg/mL, and MBC at 1000 µg/mL by EELF. EELF biofilms showed reduced dry weight and acidogenicity of S. mutans in biofilms. GA and EG reduced viable cells, glucans soluble in alkali, acidogenicity, aciduricity and downregulated expression of gtfB, gtfC and gtfD genes in biofilms. SEM images of GA and EG biofilms showed a reduction of biomass, exopolysaccharide and microcolonies of S. mutans. CONCLUSIONS: The ethanolic extract of fruit and seed of L. ferrea, gallic acid and ethyl gallate showed great antimicrobial activity and inhibition of adhesion, reduction of acidogenicity and aciduricity in S. mutans biofilms. The results obtained in vitro validate the use of this plant in ethnopharmacology, and open opportunities for the development of new oral anticariogenic agents, originated by plants that can inhibit pathogenic biofilm that leads to the development of caries.

A importância da tomada da palavra na escola / La importancia de la toma de la palabra en la escuela / The importance of the seizure of speech in school

Um dos princípios que regem o capitalismo e a sociedade de consumo é o de que as mercadorias devem ser rapidamente consumidas para que os consumidores acreditem estar sempre precisando de novas. Como bem percebeu Lacan, essa lógica é oposta à do desejo que tem como objeto o próprio desejar. Nesses termos, para que a escola não seja incorporada à lógica da sociedade de consumo, a partir das análises de Lajonquière sobre as relações entre a mestria e a tomada da palavra, este texto sugere a possibilidade de uma escola que abra uma perspectiva para o desejo de desejar.

Uno de los principios que rigen el capitalismo y la sociedad de consumo es el de que las mercancías deben ser rápidamente consumidas para que los consumidores crean estar siempre necesitando de nuevas mercancías. Como bien percibió Lacan, esa lógica es opuesta a la del deseo, cuyo objeto es el propio desear. En esos términos, para que la escuela no sea incorporada a la lógica de la sociedad de consumo, a partir de los análisis de Lajonquière sobre las relaciones entre la maestría y la toma de la palabra, este texto sugiere la posibilidad de una escuela que abra una perspectiva para el deseo de desear.

One of the principles governing capitalism and consumer society is that commodities must be consumed quickly so that consumers believe that they are always in need of new commodities. As Lacan understood, this logic is opposite to the logic of desire, whose object is desire itself. In these terms, to prevent the school from being incorporated into the logic of the consumer society, and drawing on Lajonquière's analyses of the relations between the mastery and the seizure of speech, this paper suggests the possibility of a school that opens a perspective to the desire to desire.

In vivo magnetic resonance imaging tracking of C6 glioma cells labeled with superparamagnetic iron oxide nanoparticles.

OBJECTIVE: The aim of the current study was to monitor the migration of superparamagnetic iron oxide nanoparticle (SPION)-labeled C6 cells, which were used to induce glioblastoma tumor growth in an animal model, over time using magnetic resonance imaging (MRI), with the goal of aiding in tumor prognosis and therapy. METHODS: Two groups of male Wistar rats were used for the tumor induction model. In the first group (n=3), the tumors were induced via the injection of SPION-labeled C6 cells. In the second group (n=3), the tumors were induced via the injection of unlabeled C6 cells. Prussian Blue staining was performed to analyze the SPION distribution within the C6 cells in vitro. Tumor-inducing C6 cells were injected into the right frontal cortex, and subsequent tumor monitoring and SPION detection were performed using T2- and T2*-weighted MRI at a 2T field strength. In addition, cancerous tissue was histologically analyzed after performing the MRI studies. RESULTS: The in vitro qualitative evaluation demonstrated adequate distribution and satisfactory cell labeling of the SPIONs. At 14 or 21 days after C6 injection, a SPION-induced T2- and T2*-weighted MRI signal reduction was observed within the lesion located in the left frontal lobe on parasagittal topography. Moreover, histological staining of the tumor tissue with Prussian Blue revealed a broad distribution of SPIONs within the C6 cells. CONCLUSION: MRI analyses exhibit potential for monitoring the tumor growth of C6 cells efficiently labeled with SPIONs.

Intracellular labeling and quantification process by magnetic resonance imaging using iron oxide magnetic nanoparticles in rat C6 glioma cell line.

OBJECTIVE: To assess intracellular labeling and quantification by magnetic resonance imaging using iron oxide magnetic nanoparticles coated with biocompatible materials in rat C6 glioma cells in vitro. These methods will provide direction for future trials of tumor induction in vivo as well as possible magnetic hyperthermia applications. METHODS: Aminosilane, dextran, polyvinyl alcohol, and starch-coated magnetic nanoparticles were used in the qualitative assessment of C6 cell labeling via light microscopy. The influence of the transfection agent poly-L-lysine on cellular uptake was examined. The quantification process was performed by relaxometry analysis in T1 and T2weighted phantom images. RESULTS: Light microscopy revealed that the aminosilane-coated magnetic nanoparticles alone or complexed with poly-L-lysine showed higher cellular uptake than did the uncoated magnetic particles. The relaxivities of the aminosilane-coated magnetic nanoparticles with a hydrodynamic diameter of 50nm to a 3-T field were r1=(6.1±0.3)×10(-5) ms-1mL/µg, r2=(5.3±0.1)× 10(-4) ms(-1)mL/µg, with a ratio of r2 / r1 ≅ 9. The iron uptake in the cells was calculated by analyzing the relaxation rates (R1 and R2) using a mathematical relationship. CONCLUSIONS: C6 glioma cells have a high uptake efficiency for aminosilane-coated magnetic nanoparticles complexed with the transfection agent poly-L-lysine. The large ratio r2 / r1 ≅ 9 indicates that these magnetic nanoparticles are ideal for quantification by magnetic resonance imaging with T2-weighted imaging techniques.

In vivo magnetic resonance imaging tracking of C6 glioma cells labeled with superparamagnetic iron oxide nanoparticles / Monitoramento in vivo por imagem por ressonância magnética de células C6 de glioma marcadas com nanopartículas superparamagnéticas de óxido de ferro

Objective: The aim of the current study was to monitor the migration of superparamagnetic iron oxide nanoparticle (SPION)-labeled C6 cells, which were used to induce glioblastoma tumor growth in an animal model, over time using magnetic resonance imaging (MRI), with the goal of aiding in tumor prognosis and therapy. Methods: Two groups of male Wistar rats were used for the tumor induction model. In the first group (n=3), the tumors were induced via the injection of SPION-labeled C6 cells. In the second group (n=3), the tumors were induced via the injection of unlabeled C6 cells. Prussian Blue staining was performed to analyze the SPION distribution within the C6 cells in vitro. Tumor-inducing C6 cells were injected into the right frontal cortex, and subsequent tumor monitoring and SPION detection were performed using T2- and T2*-weighted MRI at a 2T strength. In addition, cancerous tissue was histologically analyzed after performing the MRI studies. Results: The in vitro qualitative evaluation demonstrated adequate distribution and satisfactory cell labeling of the SPIONs. At 14 or 21 days after C6 injection, a SPIONinduced T2- and T2*-weighted MRI signal reduction was observed within the lesion located in the left frontal lobe on parasagittal topography. Moreover, histological staining of the tumor tissue with Prussian Blue revealed a broad distribution of SPIONs within the C6 cells. Conclusion: MRI analyses exhibit potential for monitoring the tumor growth of C6 cells efficiently labeled with SPIONs.

Objetivo: Realizar monitoramento temporal por imagem por ressonância magnética da migração de células C6 marcadas com nanopartículas superparamagnéticas de óxido de ferro utilizadas na indução de tumor de glioblastoma no modelo animal, com o intuito de auxiliar no prognóstico e na terapêutica de tumores. Métodos: Para o modelo animal de indução de tumor, foram utilizados ratos Wistar machos, divididos em dois grupos. No primeiro grupo (n=3), o tumor foi induzido por células C6 marcadas com nanopartículas superparamagnéticas de óxido de ferro e, no segundo grupo, (n=3) o tumor foi induzido por C6 não marcadas. Foi realizada análise in vitro da distribuição intracelular das nanopartículas superparamagnéticas de óxido de ferro nas células C6 mediante coloração de azul da prússia. As células C6 para a indução de tumor foram implantadas no córtex frontal direito. Posteriormente, foram realizados o monitoramento tumoral e a detecção das nanopartículas superparamagnéticas de óxido de ferro por sequências de imagem por ressonância magnética ponderadas em T2 e T2*, em campo de 2T. Após os estudos de imagem por ressonância magnética, o tecido tumoral foi submetido à análise histológica. Resultados: A avaliação qualitativa do estudo in vitro mostrou boa distribuição e satisfatória marcação celular com nanopartículas superparamagnéticas de óxido de ferro. No monitoramento realizado por imagem por ressonância magnética, foi observada, no 14o e 21o dia, redução do sinal em T2 e T2*, induzida pelas nanopartículas superparamagnéticas de óxido de ferro, na lesão localizada no lobo frontal esquerdo em topografia parassagital. Por meio da marcação com azul da prússia, a análise histológica do tecido tumoral revelou que, nas células C6, ainda encontramos uma vasta distribuição das nanopartículas superparamagnéticas de óxido de ferro. Conclusão: A imagem por ressonância magnética apresenta-se com alto potencial para o monitoramento das células C6 marcadas eficientemente com nanopartículas superparamagnéticas de óxido de ferro na avaliação do crescimento tumoral.

Intracellular labeling and quantification process by magnetic resonance imaging using iron oxide magnetic nanoparticles in rat C6 glioma cell line / Marcação intracelular e processo de quantificação por imagem por ressonância magnética utilizando nanopartículas magnéticas de óxido de ferro em células da linhagem C6 de glioma de rato

Objective: To assess intracellular labeling and quantification by magnetic resonance imaging using iron oxide magnetic nanoparticles coated with biocompatible materials in rat C6 glioma cells in vitro. These methods will provide direction for future trials of tumor induction in vivo as well as possible magnetic hyperthermia applications. Methods: Aminosilane, dextran, polyvinyl alcohol, and starch-coated magnetic nanoparticles were used in the qualitative assessment of C6 cell labeling via light microscopy. The influence of the transfection agent poly-L-lysine on cellular uptake was examined. The quantification process was performed by relaxometry analysis in T1 and T2weighted phantom images. Results: Light microscopy revealed that the aminosilane-coated magnetic nanoparticles alone or complexed with poly-L-lysine showed higher cellular uptake than did the uncoated magnetic particles. The relaxivities of the aminosilane-coated magnetic nanoparticles with a hydrodynamic diameter of 50nm to a 3-T were r1=(6.1±0.3)×10-5 ms-1mL/mug, r2=(5.3±0.1)× 10-4 ms-1mL/mug, with a ratio of r2 / r1 approximately equal to 9. The iron uptake in the cells was calculated by analyzing the relaxation rates (R1 and R2) using a mathematical relationship. Conclusions: C6 glioma cells have a high uptake efficiency for aminosilane-coated magnetic nanoparticles complexed with the transfection agent poly-L-lysine. The large ratio r2 / r1 approximately equal to 9 indicates that these magnetic nanoparticles are ideal for quantification by magnetic resonance imaging with T2-weighted imaging techniques.

Objetivo: Avaliar a marcação intracelular e o processo de quantificação por imagem por ressonância magnética usando nanopartículas magnéticas à base de óxido de ferro recobertas com materiais biocompatíveis em células da linhagem de glioma de rato C6 em experimentos in vitro. Esses métodos visam orientar ensaios futuros de indução de tumor in vivo, bem como possíveis aplicações da técnica de magneto-hipertermia. Métodos: Na avaliação qualitativa da marcação de células C6, realizada mediante microscopia óptica comum, foram utilizadas nanopartículas magnéticas recobertas com aminosilana, dextrana, álcool polivinílico e amido. A influência do agente de transfecção poly-L-lisine na captação celular foi analisada. O processo de quantificação foi realizado mediante a análise de relaxometria em imagens ponderadas em T1 e T2 do phantom. Resultados: A avaliação por microscopia óptica comum mostrou que nanopartículas magnéticas recobertas com aminosilana complexadas e não complexadas com poly-L-lisine apresentam melhor captação pelas células. As relaxatividades de nanopartículas magnéticas recobertas com aminosilana com diâmetro hidrodinâmico de 50nm para um campo de 3T foram: r1=(6,1±0,3)×10-5ms-1mL/mig, r2=(5,3±0,1)×10-4ms-1mL/mig; com uma razão de r2 / r1 aproximadamente igual a 9. O ferro captado pelas células foi calculado pela análise das taxas de relaxação (R1 e R2) mediante relação matemática. Conclusões: Linhagem de células C6 marcadas com nanopartículas magnéticas revestidas com aminosilana e complexadas com o agente de transfecção poly-L-lisine tem uma alta eficiência de captação das nanopartículas magnéticas. A grande razão r2 / r1 aproximadamente igual a 9 determina que essas nanopartículas magnéticas sejam ideais para estudar o processo de quantificação por imagem por ressonância magnética com técnicas de imagem ponderadas em T2.

Princípios da fantasia e da paixão na filosofia de Hume / Principles of fantasy and passion on the philosophy of David Hume

No tratado da natureza humana, principal obra do filósofo escocês David Hume (1740), encontramos uma detalhada teoria sobre a formação das idéias da imaginação. Para HUME, o "sistema de realidade", constituído pelas impressões dos sentidos e pela memória, não é suficiente para a formação da maior parte das idéias, necessárias à vida cotidiana e à ciência. Para suprir esse espaço deixado pela memória, a imaginação reorganiza as idéias num segundo "sistema de realidade". É neste contexto de imaginação e de fantasia que HUME explica a importância e o funcionamento da crença e da paixão. O presente artigo pretende apresentar as principais teses do autor, bem como aproximá-las do público interessado nos temas atuais da psicologia e da psicanálise