Modulation of drug resistance and biofilm formation of Staphylococcus aureus isolated from the oral cavity of Tunisian children

Abstract Objectives: This study aims to investigate the antimicrobial and the anti-biofilm activities of Lactobacillus plantarum extract (LPE) against a panel of oral Staphylococcus aureus (n = 9) and S. aureus ATCC 25923. The in vitro ability of LPE to modulate bacterial resistance to tetracycline, benzalchonium chloride, and chlorhexidine were tested also. Methods: The minimum inhibitory concentrations (MICs) and the minimal bactericidal concentrations of Lactobacillus plantarum extract, tetracycline, benzalchonium chloride and clohrhexidine were determined in absence and in presence of a sub-MIC doses of LPE (1/2 MIC). In addition, the LPE potential to inhibit biofilm formation was assessed by microtiter plate and atomic force microscopy assays. Statistical analysis was performed on SPSS v. 17.0 software using Friedman test and Wilcoxon signed ranks test. These tests were used to assess inter-group difference (p < 0.05). Results: Our results revealed that LPE exhibited a significant antimicrobial and anti-biofilm activities against the tested strains. A synergistic effect of LPEs and drug susceptibility was observed with a 2–8-fold reduction. Conclusion: LPE may be considered to have resistance-modifying activity. A more detailed investigation is necessary to determine the active compound responsible for therapeutic and disinfectant modulation.

Determinación de la calidad de pulido de resinas de nanorrelleno empleando un microscopio de fuerza atómica / Determining the polishing quality of nanofilled resins using an atomic force microscope

Introducción: Los procedimientos de acabado y pulido de las restauraciones dentarias son fases determinantes en la práctica odontológica,ya que las superficies bien acabadas y pulidas aumentan la longevidadde la restauración, disminuyen la acumulación de placa y reducen las modificaciones del color marginal a la restauración y superficie. Objetivo: El propósito de este estudio fue evaluar tres diferentes sistemas de pulido: discos Sof-Lex, copas pulidoras Jiff y y sistema de un solopaso OptraPol, en función de la superficie obtenida en tres marcas deresinas estéticas nanohíbridas para zona anterior y posterior...

Introduction: The procedures for finishing and polishing dental restorations are crucial phases in dental practice, as well-fi nished andwell-polished surfaces increase the longevity of the restoration andreduce the buildup of plaque and marginal color changes in both therestoration and the surface. Objective: The purpose of this study wasto evaluate three diff erent polishing systems: Sof-Lex™, Jiff y® polishercups, and the OptraPol one-step system, based on the surface obtainedusing three brands of cosmetic nanohybrid resins in the anterior and posterior regions...

Antipsicóticos para la esquizofrenia: paradigma de los medicamentos psiquiátricos / Antipsychotics for schizophrenia: the paradigm of psychiatric drugs

Los antipsicóticos no parecen revertir las causas de la esquizofrenia y, aunque son fármacos que pueden aliviar los síntomas a corto y mediano plazo, a largo plazo pueden no ser beneficiosos e incluso ser contraproducentes. Su empleo debería limitarse a situaciones agudas con agitación y tensión incapacitante. Presentan considerables efectos adversos y, ante la negativa de una persona a seguir tomándolos, adoptar una estrategia de reducción de daños apoyando y supervisando la retirada puede ser preferible a la coerción. Existen alternativas a los neurolépticos. Los prescriptores deberían estar más atentos y considerar las valoraciones que los usuarios hacen de sus efectos. El apego a las guías de tratamiento es escaso, seguramente por basarse en ensayos clinicos de calidad deficente, que deben mejorar y prolongarse en el tiempo. La raíz del problema probablemente se encuentra en la tautología sobre la etiología y naturaleza biológica de lo que llaman esquizofrenia, que realmente no parece ser más que un constructo ideológico-comercial.

Antipsychotic drugs do not appear to reverse the causes of schizophrenia, and although they can relieve symptoms in the short to medium term, in the long term they may not be beneficial and could even be counterproductive. Their use should be limited to acute situations in which agitation and tension is disabling. The drugs have significant adverse effects, and given the refusal of a person to continue taking them, a harm reduction strategy to support and monitor the withdrawal may be preferable to coercion. There are alternatives to neuroleptics. Prescribers should be more vigilant and consider the assessments of users regarding the drugs' effects. Adherence to treatment guidelines is low, probably because the guidelines are based on clinical trials of deficient quality which consequently should be improved and extended over a greater period of time. The root of the problem is likely the tautology on the etiology and biological nature of what is known as schizophrenia, which in fact does not seem to be more than a commercial and ideological construct.

Measuring bacterial cells size with AFM

Atomic Force Microscopy (AFM) can be used to obtain high-resolution topographical images of bacteria revealing surface details and cell integrity. During scanning however, the interactions between the AFM probe and the membrane results in distortion of the images. Such distortions or artifacts are the result of geometrical effects related to bacterial cell height, specimen curvature and the AFM probe geometry. The most common artifact in imaging is surface broadening, what can lead to errors in bacterial sizing. Several methods of correction have been proposed to compensate for these artifacts and in this study we describe a simple geometric model for the interaction between the tip (a pyramidal shaped AFM probe) and the bacterium (Escherichia coli JM-109 strain) to minimize the enlarging effect. Approaches to bacteria immobilization and examples of AFM images analysis are also described.

Análise topográfica de limas de quatro diferentes sistemas rotatórios, antes e depois do décimo segundo uso, utilizando-se dois tipos de microscopia: força atômica e a eletrônica de varredura / Analysis of four different rotatory systems files, before and after the twelfth use, using two types of microscopy: atomic force and scanning electron microscopy

O preparo do canal radicular pode sofrer limitações, frente à situação anatômica de canais com curvaturas acentuados, promovendo desgastes e deformações dos instrumentos usados nesta fase cirúrgica. O objetivo deste estudo foi avaliar, comparativamente, a topografia da superfície do terço cervical e apical de quatro diferentes sistemas rotatórios antes e depois do uso por doze vezes, em blocos de resina com canais simulados padronizados com curvatura de 45° e analisados através da microscopia de força atômica - MFA e microscopia eletrônica de varredura - MEV. Foram utilizados 144 blocos de resina com canais simulados e curvatura padronizada. Os blocos foram divididos em quatro grupos e preparados segundo recomendação dos fabricantes pela técnica coroa-ápice: Grupo 1 - K3@; Grupo 2 - Protaper Universal@; Grupo 3 - Twisted Files@ e o Grupo 4 - Biorace@. A cada preparo, os instrumentos foram lavados e autoclavados. Foram selecionados 24 instrumentos sendo, 3 instrumentos novos e 3 após o 12° uso, de cada grupo. Estes instrumentos foram analisados na MFA (análise quantitativa) e MEV (análise qualitativa)...

Root canal preparation may suffer limitations facing the anatomical situation of accentuated curved root canais,. promoting wear and deformation of surgical instruments used at this stage. The aim of this study was to evaluate, comparatively, the topography of the cervical third and apical surfaces of four different rotatory systems before and after use by twelve times, in blocks of resin with standardized simulated canais with 45 o curvature and analyzed by Atomic Force Microscopy ¬AFM and Scanning Electron Microscopy - SEM. 144 resin blocks with simulated canais and standardized curvature were used. The blocks were divided into four groups and prepared according to manufacturers I recommendation by Crown-Apex technique: Group 1 - K3@; Group 2 - Protaper@ Universal; Group 3 - Twisted Files@ and Group 4 - Biorace@. After each canal preparation, the instruments were washed and autoclaved. 24 instruments were selected being, 3 new instruments and 3 after the 12th use, for each group. These instruments were analyzed through AFM (quantitative analysis) and SEM (qualitative analysis). In quantitative evaluation, it was used the average of the Rms (Root mean square) values of the four experimental groups, analyzed through the AFM technique, only the specimens of cervical third...

Análise da proliferaçäo endosteal após a colocaçäo de "discos" de titânio c.p. em coelhos, tratados por diferentes formas / Analysis of the endosseus proliferation after the titanium c.p. \"discs\" implantation in rabbits, by different treatments

Recentemente, tem tornado aparente que o sucesso do implante endosteal é largamente, se näo totalmente, determinado pela biocompatibilidade do material usado. Esta biocompatibilidade parece estar determinada näo somente pela natureza química do material, mas também pela propriedade micromorfológica da superfície do implante. Os resultados apresentam uma avaliaçäo histológica da cicatrizaçäo inicial da implantaçäo de discos de titânio c.p. com superfície porosa fixados endostealmente. Para testar esta avaliaçäo foram utilizados 12 coelhos machos com peso médio de 3,2 Kg., sendo que cada animal recebeu 2 discos de titânio c.p.. Em todos os animais, os discos de titânio foram utilizados para avaliaçäo histológica de crescimento ósseo...