RESUMO
The objective of this work is to test the performance of new synthetic polydimethylsiloxane (PDMS)-based bed particles acting as carriers for bacteria biofilms. The particles obtained have a highly interconnected porous structure which offers a large surface adsorption area to the bacteria. In addition, PDMS materials can be cross-linked by copolymerization with other polymers. In the present work we have chosen two hydrophilic polymers: xanthan gum polysaccharide and tetraethoxysilane (TEOS). This versatile composition helps to modulate the interfacial hydrophobic/hydrophilic balance at the particle surface level and the roughness topology and pore size distribution, as revealed by scanning electron microscopy. Biofilm formation of a consortium isolated from a tannery effluent enriched in Sulphate Reducing Bacteria (SRB), and pure Acidithiobacillus ferrooxidans (AF) strains were assayed in three different bed particles synthesized with pure PDMS, PDMS-xanthan gum and PDMS-TEOS hybrids. Bacterial viability assays using confocal laser scanning fluorescence microscopy indicate that inclusion of hydrophilic groups on particle's surface significantly improves both cell adhesion and viability.
Assuntos
Acidithiobacillus/fisiologia , Biofilmes/crescimento & desenvolvimento , Dimetilpolisiloxanos/química , Sulfatos/metabolismo , Bactérias/citologia , Bactérias/metabolismo , Aderência Bacteriana/fisiologia , Células Imobilizadas/fisiologia , Interações Hidrofóbicas e Hidrofílicas , Microscopia Confocal , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Tamanho da Partícula , Polissacarídeos Bacterianos/química , Porosidade , Silanos/química , Propriedades de SuperfícieRESUMO
AIM: To evaluate the cytotoxicity and genotoxicity of sodium percarbonate (SPC) in comparison with bleaching agents used on discoloured pulpless teeth. METHODOLOGY: The cytotoxicity and genotoxicity of bleaching agents were evaluated both in their pure form as well as at concentrations commonly used in clinical practice. Hydrogen peroxide (HP), carbamide peroxide (CP), sodium perborate (SP) and SPC were diluted in Dulbecco's modified Eagle's medium (DMEM) in series. To evaluate the cytotoxicity, the survival of 3T3/NIH mouse fibroblasts was measured photometrically using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after a 24 h-exposure period. Genotoxicity was indicated by micronuclei (MN) formation, and modification of the normal cell was analysed by light microscopy (400x). Statistical analysis was performed by one-way anova, followed by a multiple-comparison Tukey post hoc test (P < 0.05). RESULTS: All groups exhibited a dose-dependent cytotoxicity. However, CP showed a similar cytotoxic effect when compared with DMEM-untreated control (UC) group. HP and SPC were significantly more cytotoxic than SP. The genotoxicity test showed that SPC and SP had an intermediate rate of MN frequency when compared with the UC group. The mean rate of MN frequency for HP was higher and statistically more significant than for the other groups tested. No difference was observed when CP and UC groups were compared. CONCLUSIONS: Sodium percarbonate showed cytotoxicity and genotoxicity similar to those of the other products tested. However, before SPC is used clinically, studies should be conducted to confirm its safety in vivo.
Assuntos
Carbonatos/toxicidade , Fibroblastos/efeitos dos fármacos , Peróxidos/toxicidade , Clareamento Dental/efeitos adversos , Análise de Variância , Animais , Boratos/toxicidade , Peróxido de Carbamida , Linhagem Celular , Sobrevivência Celular , Cavidade Pulpar/efeitos dos fármacos , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Fibroblastos/citologia , Peróxido de Hidrogênio/toxicidade , Camundongos , Testes para Micronúcleos , Oxidantes/toxicidade , Estatísticas não Paramétricas , Clareamento Dental/métodos , Descoloração de Dente/tratamento farmacológico , Dente não Vital , Testes de Toxicidade , Ureia/análogos & derivados , Ureia/toxicidadeRESUMO
The development and characterization of a bacteriocin-containing polyethylene-based film is described, incorporating lactocin 705 and lactocin AL705, produced by Lactobacillus curvatus CRL705, and nisin. Three different procedures to obtain lactocin 705 and AL705 solution were evaluated, with the partially purified aqueous bacteriocin solution showing the highest inhibitory activity against indicator strains (Lactobacillus plantarum CRL691 and Listeria innocua 7). Pouch contact, soaking and a contact method were compared for incorporating bacteriocins onto PE-based films. Contact between the PE film and bacteriocin solution was the most effective, resulting in a more uniform distribution of bacteriocins on the film surface and using less active solution. The minimal inhibitory concentration of bacteriocin solution was 267 AU cm(-3) (lactocin 705) and 2133 AU cm(-3) (lactocin AL705), while the minimal contact time was 1 h. When relative inhibition area for antilisterial activity of the active films was compared, those treated with L. curvatus CRL705 bacteriocins displayed higher inhibitory activity than nisin-treated films. Functional properties of active PE-films containing lactocin 705 and AL705 showed no differences compared with non-active control films. Bacteriocin-active PE-based films are shown to be highly effective in inhibiting growth of Listeria. The potential use of commercially available packaging films as bacteriocins carriers may benefit active-packaging systems.
Assuntos
Bacteriocinas/farmacologia , Microbiologia de Alimentos , Embalagem de Alimentos/métodos , Lactobacillus/metabolismo , Polietileno/química , Bacteriocinas/biossíntese , Conservação de Alimentos/métodos , Lactobacillus plantarum/efeitos dos fármacos , Lactobacillus plantarum/crescimento & desenvolvimento , Listeria/efeitos dos fármacos , Listeria/crescimento & desenvolvimento , Testes de Sensibilidade MicrobianaRESUMO
A study was carried out on T. cruzi infection in pregnant women in the Guemes area in Salta province; the rate of infection was 12.3%. Of newborn children studied by the microhematocrit technique, 8.8% were diagnosed with Chagas' disease. All of them were treated with benznidazol (5mg/kg/day) for one month; all of them presented anemia, which was interpreted to be an adverse drug reaction. The microhematocrit technique is believed to represent the best option for diagnosis of this disease in newborn children. A diagnostic methodology to follow the course of the infection is proposed.
Assuntos
Doença de Chagas/congênito , Argentina , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Feminino , Humanos , Recém-Nascido , Gravidez , PrevalênciaRESUMO
Se describe un caso de displasia cementaria periapical en una paciente postmenopausica, y que presento zonas radiolucentes y radiopacas combinadas, cuyo diagnostico diferencial es muy importante. El diagnostico histopatologico concordo con el clinico
Assuntos
Pessoa de Meia-Idade , Humanos , Feminino , Cementoma , Neoplasias MaxilaresRESUMO
Dentro del estudio tranversal de crecimiento y desarrollo de jovenes escolares meridenos, se evaluo el desarrollo puberal de los mismos. La poblacion estudiada comprendio 1.946 escolares; 1.044 hembras y 902 varones, cuyas edades oscilaban entre 7 y 20 anos. De estos, 342 varones, y 535 hembras presentaron algun grado de desarrollo puberal se utilizaron los estadios de 1 a 5 de Tanner, para glandula mamaria (GM), vello pubiano (VP) y genitales (G). El desarrolo testicular se evaluo utilizando el orquidometro de Prader, y la edad de la menarquia de acuerdo al metodo de "statu quo". Los resultados obtenidos en las hembras dieron una media (X +/- D.T.) 12,19 +/- 1,29 para GM2; 12,14 +/- 0,96 para VP2; 16,05 +/- 1,71 para GM5; 15,09 +/- 1,76 para VP2. La menarquia se presento a los 12,55 +/- 1,29. Para los varones, una media de 13,35 +/- 0,90 en G2 13,37 +/- 1,13 para VP2; 16,59 +/- 1,95 para G5 y 16,79 +/- 2,33 para VP5.En cuanto al volumen testicular el estadio adulto lo alcazaron en promedio a los 15,59 +/- 3,15 anos. Comparando las muestras de varones y hembras meridenos con los resultados previos de los autores en ninos de Caracas, conseguimos que los meridenos inician y finalizan mas tardiamente la pubertad. En relacion a datos publicados para Cuba, EE.UU e Inglaterra, nuestros ninos indican su pubertad mas tardiamente, pero alzanzan su madurez dentro de los limites establecidos en esas investigaciones