VALIDACIÓN DE UN MÉTODO PARA LA DETERMINACIÓN DE ÁCIDO BENZÓICO EN PRODUCTOS LÁCTEOS

Se realizó la determinación de Ácido Benzoico (AB) en diferentes productos lácteos con la finalidad de verificar que cumplan con los límites permitidos por la normatividad mexicana. El método utilizado fue la Cromatografía de Líquidos de Alta Resolución. Todos los quesos analizados estuvieron dentro de los límites (0.05 a 0-1%), excepto el tipo Petit suisse con un 0.27%. A pesar de que el AB es considerado como una sustancia segura, es importante tomar en cuenta este resultado, ya que su consumo en exceso puede causar irritación en tracto digestivo, así como una sensibilización química.Palabras clave: ácido benzoico, productos lácteos, conservadores, ácido benzoico por HPLC, validación.Benzoic acid, dairy products, conservatives, benzoic acid by HPLC, validation

Association of Polyaminergic Loci With Anxiety, Mood Disorders, and Attempted Suicide

The polyamine system has been implicated in a number of psychiatric conditions, which display both alterations in polyamine levels and altered expression of genes related to polyamine metabolism. Studies have identified associations between genetic variants in spermidine/spermine N1-acetyltransferase (SAT1) and both anxiety and suicide, and several polymorphisms appear to play important roles in determining gene expression.We genotyped 63 polymorphisms, spread across four polyaminergic genes (SAT1, spermine synthase (SMS), spermine oxidase (SMOX), and ornithine aminotransferase like-1 (OATL1)), in 1255 French-Canadian individuals who have been followed longitudinally for 22 years. We assessed univariate associations with anxiety, mood disorders, and attempted suicide, as assessed during early adulthood. We also investigated the involvement of gene-environment interactions in terms of childhood abuse, and assessed internalizing and externalizing symptoms as endophenotypes mediating these interactions. Overall, each gene was associated with at least one main outcome: anxiety (SAT1, SMS), mood disorders (SAT1, SMOX), and suicide attempts (SAT1, OATL1). Several SAT1 polymorphisms displayed disease-specific risk alleles, and polymorphisms in this gene were involved in gene-gene interactions with SMS to confer risk for anxiety disorders, as well as gene-environment interactions between childhood physical abuse and mood disorders. Externalizing behaviors demonstrated significant mediation with regards to the association between OATL1 and attempted suicide, however there was no evidence that externalizing or internalizing behaviors were appropriate endophenotypes to explain the associations with mood or anxiety disorders. Finally, childhood sexual abuse did not demonstrate mediating influences on any of our outcomes.These results demonstrate that genetic variants in polyaminergic genes are associated with psychiatric conditions, each of which involves a set of separate and distinct risk alleles. As several of these polymorphisms are associated with gene expression, these findings may provide mechanisms to explain the alterations in polyamine metabolism which have been observed in psychiatric disorders

Groundwater arsenic contamination and their variations on episode of drought: Ter River delta in Catalonia, Spain

Abstract The analysis and prospection using hydrogeochemical methodologies on arsenic (As) contamination episode in region of Spain (Girona, Cataluña) was investigated on the period (2000–2011), to analyze the mechanisms and characteristics of process on the solubilization of As in groundwater and effects of the episode of severe drought (2006–2007) on hydrogeochemical characteristics of the aquifer. The aquifer of study is a Mediterranean Delta; the geology of the zone has influence from sedimentary deposition of Ter River Basin and the prograde and draw back of the history coastline. The aquifer is an alluvial system where mean concentration of (As) is 30 µg/L in groundwater; parallel to this, the concentrations of elements iron (Fe) and manganese (Mn) exceed the guidelines of the World Health Organization (Guidelines for drinking-water quality electronic resource incorporating 1st and 2nd addenda, vol 1, Recommendations, 3rd edn, World Health Organization, Geneva, 2006) for drinking water. Range concentrations from other elements found in the groundwater were: Aluminum (Al, 4–716 µg/L), Barium (Ba, 48–603 µg/L), Cupper (Cu, 0.2–105.3 µg/L), Chrome (Cr, 1.1–47 µg/L) and Nickel (Ni, 1–51 µg/L). The arsenic solubilization trigger mechanism comes from desorption of oxide minerals and reduction related on neutral pH and reductive environment; the source of this kind of oxides is probably from marine sediments deposited in the process of delta’s formation. During the climatic event of drought (2006–2007), the As concentration was responding to decline levels of the water volume on the aquifer, increasing their concentration and localized in a small area of the study zone, and these are effects of the reduction in groundwater flow on the aquifer

Dioxins in beef samples from Mexico using a low resolution GC/MS screening method

Dioxins in beef were quantified by high resolution gas chromatography coupled to low-resolution mass spectrometry (GC/LRMS). The analyses were performed according to the minimum requirements described in the USEPA 1613 method with some minor modifications. Levels found in the samples were in the range 1.02–8.04 pg WHO-TEQ PCDDs/PCDFs g−1 fat. For comparison purposes, the maximum level allowed by the European Union is 3 pg WHO-TEQ PCDDs/PCDFs g−1 fat, and some of these samples surpassed the above-mentioned limit and can be considered as contaminated food. The results confirm that a preliminary screening of dioxins in beef can be performed by GC/LRMS. As far as we know, this is the first report of dioxins in beef in Mexico. After the appropriated tests, the applied methodology could be considered as an alternative screening method for the analysis of PCDD/Fs in other food products.Peer reviewe

Variación de las poblaciones microbianas del suelo por la adición de hidrocarburos

Las poblaciones microbianas son alteradas por la presencia de hidrocarburos, particularmente las que tienen la capacidad de utilizarlos como fuente de carbono. El objetivo del presente trabajo fue evaluar el efecto de los hidrocarburos sobre las poblaciones microbianas del suelo. Se realizó el experimento en condiciones de invernadero con cinco tratamientos: T1 = testigo; T2 = suelo + aceite; T3 = suelo + aceite + nitrógeno y fósforo (NP); T4 = suelo + diesel y T5 = suelo + diesel + nitrógeno y fósforo (NP). Se utilizó suelo agrícola contaminado ex profeso, con 10% en peso con aceite de lubricación automotriz en el tratamiento T2 y T3 y diesel en el tratamiento T4 y T5. La variación en las poblaciones microbianas del suelo fue determinada mediante la técnica del número más probable (NMP). Se midió la respiración edáfica del suelo en estudio y el contenido de hidrocarburos totales de petróleo. Los resultados indicaron que los microorganismos del suelo y degradadores de hidrocarburos fueron estimulados por la presencia de aceite y diesel. La población fluctuó de 1 × 105 UFC g-1 del suelo testigo hasta 1 × 108 UFC g-1 en el suelo con diesel más nitrógeno y fósforo, que fue el valor más alto. La adición de ambos hidrocarburos aumentó la actividad biológica del suelo evaluada como el índice de respiración edáfica y medida como producción de CO2, la cual osciló de 1% del suelo testigo hasta 9% en el tratamiento con diesel y nutrimentos. Se concluye que el diesel y aceite de lubricación automotriz influyeron en la dinámica de las poblaciones microbianas del suelo, ya que la comunidad microbiana los utiliza como fuente de carbono, indicado por la producción de CO2, subproducto de la degradación de los hidrocarburos. El balance del contenido de carbono, nitrógeno y fósforo (C:N:P), en los suelos, favorece el aprovechamiento de los hidrocarburos por las poblaciones microbianas del suelo; las poblaciones microbianas están limitadas al sustrato, es decir, a la cantidad disponible de hidrocarburos en el suelo