Gene expression during the development of Mycobacterium smegmatis biofilms on hydroxyapatite surfaces / Expresión génica durante el desarrollo de biopelículas de Mycobacterium smegmatis en superficies de hidroxiapatita

Bacterial biofilms are a consortium of bacteria that are strongly bound to each other and the surface on which they developed irreversibly. Bacteria can survive adverse environmental conditions and undergo changes when transitioning from a planktonic form to community cells. The process of mycobacteria adhesion is complex, involving characteristics and properties of bacteria, surfaces, and environmental factors; therefore, the formation of different biofilms is possible. Cell wall-, lipid-, and lipid transporter-related genes (glycopeptidolipids, GroEL1, protein kinase) are important in mycobacterial biofilm development. We investigated gene expression during in vitro development of Mycobacterium smegmatis biofilms on a hydroxyapatite (HAP) surface. Biofilm formation by M. smegmatis cells was induced for 1, 2, 3, and 5 days on the HAP surface. Mycobacteria on polystyrene generated an air–liquid interface biofilm, and on the fifth day, it increased by 35% in the presence of HAP. Six genes with key roles in biofilm formation were analyzed by real-time RT‒qPCR during the biofilm formation of M. smegmatis on both abiotic surfaces. The expression of groEL1, lsr2, mmpL11, mps, pknF, and rpoZ genes during biofilm formation on the HAP surface did not exhibit significant changes compared to the polystyrene surface. These genes involved in biofilm formation are not affected by HAP.(AU)

The potential of Bacillus and Enterococcus probiotic strains to combat helicobacter pylori attachment to the biotic and abiotic surfaces / El potencial de las cepas probióticas de Bacillus y Enterococcus para combatir la adhesión de Helicobacter pylori a las superficies bióticas y abióticas

The prevention of biofilm formation plays a pivotal role in managing Helicobacter pylori inside the body and the environment. This study showed in vitro potentials of two recently isolated probiotic strains, Bacillus sp. 1630F and Enterococcus sp. 7C37, to form biofilm and combat H. pylori attachment to the abiotic and biotic surfaces. Lactobacillus casei and Bifidobacterium bifidum were used as the reference probiotics. The biofilm rates were the highest in the solid–liquid interface for Lactobacillus and Bifidobacterium and the air–liquid interface for Bacillus and Enterococcus. The highest tolerances to the environmental conditions were observed during the biofilm formations of Enterococcus and Bifidobacterium (pH), Enterococcus and Bacillus (bile), and Bifidobacterium and Lactobacillus (NaCl) on the polystyrene and glass substratum, respectively. Biofilms occurred more quickly by Bacillus and Enterococcus strains than reference strains on the polystyrene and glass substratum, respectively. Enterococcus (competition) and Bacillus (exclusion) achieved the most inhibition of H. pylori biofilm formations on the polystyrene and AGS cells, respectively. Expression of luxS was promoted by Bacillus (exclusion, 3.2 fold) and Enterococcus (competition, 2.0 fold). Expression of ropD was decreased when H. pylori biofilm was excluded by Bacillus (0.4 fold) and Enterococcus (0.2 fold) cells. This study demonstrated the ability of Bacillus and Enterococcus probiotic bacteria to form biofilm and combat H. pylori biofilm formation.(AU)

Hipercalcemia como efecto secundario de los quelantes de potasio / Hypercalcaemia as a side effect of potassium binding agents

La hipercalcemia es un efecto adverso potencial de las resinas cálcicas de intercambio iónico, de uso frecuente en el tratamiento y la prevención de la hiperpotasemia en la enfermedad renal crónica (ERC). Describimos una serie de siete pacientes con ERC moderada de la consulta de Nefrología Clínica (filtrado glomerular medio estimado por CKD-EPI: 41,29 ± 10,83 ml/min/1,73 m2), que presentan hipercalcemia leve en relación con el tratamiento con poliestireno sulfonato cálcico. El calcio sérico se elevó de media 0,91 ± 0,46 mg/dl, con un descenso paralelo de los niveles de hormona paratiroidea intacta (iPTH) de 49,29 ± 52,24 ng/dl de media. Tras la retirada o la reducción de la dosis, se objetivó una recuperación de las cifras de calcio e iPTH séricos. Los quelantes cálcicos de potasio se deben incluir en el diagnóstico diferencial de la hipercalcemia en pacientes con ERC no avanzada (AU)

Hypercalcaemia is a potential adverse effect of calcium-containing ion exchange resins, often used in the treatment and prevention of hyperkalaemia in chronic kidney disease (CKD). We describe a series of seven outpatients with moderate CKD (mean glomerular filtration rate estimated with the CKD-EPI formula: 41.29±10.83mL/min/1.73m2), presenting mild hypercalcaemia in relation to the treatment with calcium polystyrene sulfonate. Serum calcium increased a mean of 0.91±0.46mg/dL, with a mean concomitant decrease of serum intact parathormone (iPTH) of 52.24±49.29ng/dL. After treatment withdrawal or dose reduction, we observed a recovery of serum calcium and iPTH values. Treatment with calcium-based potassium binders should be included in the differential diagnosis of hypercalcaemia in patients with moderate CKD (AU)

Efecto in vitro de la adición de resinas de intercambio iónico sobre la biodisponibilidad de electrolitos en fórmulas de nutrición enteral artificial / The in vitro effect of the addition of ion exchange resins on the bioavailability of electrolytes in artificial enteral feeding formulas

Objetivo: Conocer la concentración iónica libre in vitro en tres fórmulasde nutrición enteral artificial estándar, tras la adición de resinasde intercambio iónico.Método: Se seleccionaron tres tipos de NEA estándar: OsmoliteHN®, Nutrison Standard® e Issosource Standard®. Las resinas de intercambioiónico empleadas fueron: poliestireno sulfonato sódico ypoliestireno sulfonato cálcico. En un vaso de precipitados se mezclaron100 ml de la NEA con 1,5 g o 3 g de las resinas de intercambioiónico durante 48 h a 37 ºC. Posteriormente se precipitaron lasmuestras y el sobrenadante obtenido se utilizó para determinar lasconcentraciones de los iones calcio, magnesio, sodio y potasio.Resultados: La adición de poliestireno sulfonato sódico a las diferentesnutriciones enterales redujo las concentraciones de los ionespotasio, calcio y magnesio en un 70,9, 78,2, y 77,6% en el caso deOsmolite HN®, en un 72,3, 69,2 y 63,5% en el caso de NutrisonStandard®, y en un 78,3, 80,5 y 74,5% en el caso de IssosourceStandard®. Por el contrario la adición de poliestireno sulfonato cálcicoredujo las concentraciones de potasio y magnesio en un 50,5y un 55,5% en el caso de Osmolite HN®, un 49,8 y un 43% en elcaso de Nutrison Standard® y en un 42,6 y un 37,7% en el caso deIssosource Standard®.Conclusiones: La adición de resinas de intercambio iónico a distintasnutriciones enterales permite reducir el contenido iónico libre invitro de éstas

Objective: To determine in vitro free ion concentration in three standardartificial enteral feeding formulas following the addition of ionexchange resins.Method: Three standard types of AEF were chosen: Osmolite HN®,Nutrison Standard® and Isosource Standard®. The ion exchange resinsused were: Sodium Polystyrene Sulfonate and Calcium PolystyreneSulfonate. 100 ml of AEF were mixed in a beaker with 1.5 g or3 g of ion exchange resins for 48 hours at 37ºC. Subsequently, thesamples were precipitated and the supernatant obtained was usedfor determining the concentrations of calcium, magnesium, sodiumand potassium ions.Results: The addition of Sodium Polystyrene Sulfonate to differenttypes of enteral feeding formulas reduced the concentrations of potassium,calcium and magnesium ions by 70%. 78.2%, and 77.6% inthe case of Osmolite HN®; by 72.3%, 69.2% and 63.5% in the case ofNutrison Standard®, and by 78.3%, 80.5% and 74.5% in the case ofIsosource Standard®. In contrast, the addition of Calcium PolystyreneSulfonate reduced the concentration of potassium and magnesiumby 50.5% and 55.5% in the case of Osmolite HN®; by 49.8% and43% in the case of Nutrison Standard® and by 42.6% and 37.7% inthe case of Isosource Standard®.Conclusions: The addition of ion exchange resins to different types ofenteral feeding formulas, allows the in vitro free ion content of theseto be reduced

Extracción de ADN con resina chelex en el análisis de la amplificación oncogénica en carcinomas de cabeza y cuello / DNA extraction using chelex resin for the oncogenic amplification analysis in nead and neck tumours

La extracción de ADN de tejido tumoral puede ser el proceso más laborioso y complejo en la amplificación de ADN mediante PCR cuando se utiliza el procedimiento con fenol-cloroformo. Comparamos este método de extracción extenso, lento y caro con otras dos técnicas basadas en el uso de resina Chelex-100. Esta resina quelante ha sido utilizada para la extracción de ADN de diferentes tejidos para su uso con la PCR. Estos procedimientos son simples, rápidos y no requieren múltiples pasos. En este trabajo comparamos la extracción de ADN procedente de 30 carcinomas epidermoides de cabeza y cuello utilizando la precipitación con solventes orgánicos, resina Chelex-100 con y sin procesamiento previo con proteinasa K. Los resultados evidencian que el procedimiento con proteinasa K y resina Chelex-100 es un método tan eficaz como la precipitación con fenol-cloroformo (AU)

DNA extraction from tissues can be the most laborious and complex step in amplifying DNA by PCR when phenol-choroform procedure is used. We compare this lengthy, slow and expensive extraction method with other two based in the use of Chelex-100 resin. This chelating resin has been applied for extracting DNA from different tissues to use with the PCR. These procedures are simple, rapid and do not require multiple steps. In this study we compared DNA extraction from 30 head and neck squamous cell carcinomas (HNSCC) using organic solvent precipitation, Chelex 100 resin with and without proteinase K pretreatment. The results show that proteinase K-Chelex 100 procedure is as efficient as the phenol-chloroform one (AU)