Size matters: Zebrafish (Danio rerio) as a model to study toxicity of nanoplastics from cells to the whole organism.

The contamination of the aquatic environment by plastic nanoparticles is becoming a major concern due to their potential adverse effects in aquatic biota. Therefore, in-depth knowledge of their uptake, trafficking and effects at cellular and systemic levels is essential to understand their potential impacts for aquatic species. In this work, zebrafish (Danio rerio) was used as a model and our aims were: i) to determine the distribution, uptake, trafficking, degradation and genotoxicity of polystyrene (PS) NPs of different sizes in a zebrafish cell line; ii) to study PS NPs accumulation, migration of immune cells and genotoxicity in larvae exposed to PS NPs; and iii) to assess how PS NPs condition the survival of zebrafish larvae exposed to a pathogen and/or how they impact the resistance of an immunodeficient zebrafish. Our results revealed that the cellular distribution differed depending on the particle size: the 50 nm PS NPs were more homogeneously distributed in the cytoplasm and the 1 µM PS NPs more agglomerated. The main endocytic mechanisms for the uptake of NPs were dynamin-dependent internalization for the 50 nm NPs and phagocytosis for the 1 µm nanoparticles. In both cases, degradation in lysosomes was the main fate of the PS NPs, which generated alkalinisation and modified cathepsin genes expression. These effects at cellular level agree with the results in vivo, since lysosomal alkalization increases oxidative stress and vice versa. Nanoparticles mainly accumulated in the gut, where they triggered reactive oxygen species, decreased expression of the antioxidant gene catalase and induced migration of immune cells. Finally, although PS NPs did not induce mortality in wild-type larvae, immunodeficient and infected larvae had decreased survival upon exposure to PS NPs. This fact could be explained by the mechanical disruption and/or the oxidative damage caused by these NPs that increase their susceptibility to pathogens.

Effect of transient thermal shocks on alcoholic fermentation performance.

Stuck and sluggish fermentations are among the main problems in winemaking industry leading to important economic losses. Several factors have been described as causes of stuck and sluggish fermentations, being exposure to extreme temperatures barely studied. The objective of this study was to identify thermal conditions leading to stuck and sluggish fermentations, focusing on the impact of an abrupt and transient decrease/increase of temperature on fermentation performance and yeast viability/vitality. Different strains of Saccharomyces cerevisiae, SBB11, T73, and PDM were evaluated in synthetic grape must fermentations. Cold shocks (9 °C and 1.5 °C for 16 h) carried out on different days during the fermentation process were unable to alter fermentation performance. Conversely, shock temperatures higher than 32 °C, applied in early stages of the process, lead to sluggish fermentation showing a delay directly related to the temperature increase. Fermentation delay was associated with a decrease in cell vitality. The impact of the heat shock on fermentation performance was different depending on the strain evaluated and nitrogen supplementation (with or without diammonium phosphate addition). None of the conditions evaluated produced a stuck fermentation and importantly, in all cases must nutrition improved fermentation performance after a heat shock.

The immune response of the scallop Argopecten purpuratus is associated with changes in the host microbiota structure and diversity.

All organisms live in close association with a variety of microorganisms called microbiota. Furthermore, several studies support a fundamental role of the microbiota on the host health and homeostasis. In this context, the aim of this work was to determine the structure and diversity of the microbiota associated with the scallop Argopecten purpuratus, and to assess changes in community composition and diversity during the host immune response. To do this, adult scallops were immune challenged and sampled after 24 and 48 h. Activation of the immune response was established by transcript overexpression of several scallop immune response genes in hemocytes and gills, and confirmed by protein detection of the antimicrobial peptide big defensin in gills of Vibrio-injected scallops at 24 h post-challenge. Then, the major bacterial community profile present in individual scallops was assessed by denaturing gradient gel electrophoresis (DGGE) of 16S rDNA genes and dendrogram analyses, which indicated a clear clade differentiation of the bacterial communities noticeable at 48 h post-challenge. Finally, the microbiota structure and diversity from pools of scallops were characterized using 16S deep amplicon sequencing. The results revealed an overall modulation of the microbiota abundance and diversity according to scallop immune status, allowing for prediction of some changes in the functional potential of the microbial community. Overall, the present study showed that changes in the structure and diversity of bacterial communities associated with the scallop A. purpuratus are detected after the activation of the host immune response. Now, the relevance of microbial balance disruption in the immune capacity of the scallop remains to be elucidated.

The detection of wooden foreign bodies: An experimental study comparing direct digital radiography (DDR) and ultrasonography.

INTRODUCTION: This experimental study compares the appropriateness of direct digital radiography (DDR) and ultrasonography at detecting soft-tissue wooden foreign bodies (FBs) in extremities. METHODS: Varying wooden FB splinters (2 mm, 5 mm and 10 mm) were inserted into eight porcine feet to simulate a patient presenting with a soft-tissue FB injury. Each of the FBs was placed in muscle distant, behind and near bone in the porcine feet. Control groups were used to check for false-positive diagnoses and, based on the presence of FBs; images were given a score depending on the level of visibility by the researcher. RESULTS: A higher detection rate was achieved for all FBs in muscle distant from bone using ultrasound. All of the 2 mm and 5 mm wooden FBs were not detected using DDR. The sensitivity in detecting the FBs was 5.8% and 30% in DDR and ultrasound respectively. CONCLUSION: Poor sensitivities and specificities were identified in this study. However, this study shows that ultrasound remains superior to DDR at identifying small foreign body objects. This study demonstrates that ultrasound can be a clinically effective tool for detecting suspected wooden FBs >5 mm in the foot and thus should be considered as the primary imaging modality of choice for referring clinicians.

Extractores químicos en la determinacion de silicio disponible en suelos ácidos, neutros y alcalinos / Chemical extractants in the evaluation of available silicon in acid soils, neutral and alkaline

El contenido de silicio disponible, generalmente, se ha determinado en suelos ácidos, lo que ha descuidado su cuantificación en otros suelos, para poder realizar recomendaciones de este elemento, acorde a su contenido para cada suelo. El objetivo fue evaluar el silicio disponible por diferentes extractores químicos en suelos del departamento de Córdoba, en Colombia. Para ello, se colectaron, a la profundidad de 20cm, muestras de suelos ácidos, neutros y alcalinos, que fueron ingresados al laboratorio de Suelos y Aguas de la Universidad de Córdoba, para determinar el contenido de silicio disponible. Los extractores químicos fueron cloruro de calcio 0,01mol L-1, ácido acético 0,5mol L-1, acetato de amonio 38,5g L-1, tampón pH 4,0 (HC2H3O2+CH3COONa) y el método propuesto por los autores, denominado solución de cloruro de bario. Para la extracción, se pesaron 5g de suelo y se le adicionó 50mL de solución extractante y la mezcla fue agitada durante 1h, a 220rpm, filtrada y dejada en reposo por 12h. La cuantificación, se realizó en un espectrofotómetro, a una longitud de onda de 66nm y la determinación química, se efectuó en serie, con tres repeticiones, las cuales, fueron analizadas por correlación y contrastes. En general, de acuerdo a los resultados de mayor a menor concentración de silicio, se presentó en la siguiente secuencia de extracción, suelos alcalinos > neutros > ácidos. Mediante las pruebas estadísticas de Tukey y contrastes, se concluyó que el método solución de cloruro de bario se puede utilizar como alternativo al método de referencia en la determinación de silicio en los tres tipos de suelos. Además, para suelos alcalinos, se puede emplear el método de acetato de amonio 38,5g L-1, como alternativa para la determinación de silicio.

The available silicon content has generally been determined in acid soils, but neglected its quantification in other soils, to be able to make recommendations of this element according to its content for each soil. The objective of this research was to evaluate the available silicon in soils of the department of Córdoba, Colombia by means of different chemical extractors. Samples of acid, neutral and alkaline soils were collected at the depth of 20cm and sent to the Laboratory of Soils and Waters of the University of Córdoba to determine the available silicon content. The chemical extractors were 0.01mol L-1 calcium chloride, 0.5mol L-1 acetic acid, 38.5g L-1 ammonium acetate, pH 4.0 buffer (HC2H3O2 + CH3COONa) and the method proposed by the authors, named barium chloride solution. For extraction, 5g of soil were weighed and 50mL of extractant was added and the mixture was stirred for 1h at 220rpm, filtered and left standing for 12h. The quantification was performed in a spectrophotometer at a wavelength of 66nm and the chemical determination was performed in series with three replicates, analyzed by correlation and contrasts. In general, according to results of higher to lower concentration, silicon was presented in the following sequence of extraction, alkaline soils> neutral> acids. By means of the Tukey test and contrasts it was concluded that the barium chloride solution could be used as alternative to the reference method in the determination of silicon in the three types of soils. In addition, for alkaline soils, the ammonium acetate method 38.5g L-1 can also be used as an alternative for the determination of silicon.

Coherence analysis of EEG in locomotion using graphs / Análisis de coherencia de señales EEG en locomoción usando grafos

Abstract: One of the most interesting brain machine interface (BMI) applications, is the control of assistive devices for rehabilitation of neuromotor pathologies. This means that assistive devices (prostheses, orthoses, or exoskeletons) are able to detect user motion intention, by the acquisition and interpretation of electroencephalographic (EEG) signals. Such interpretation is based on the time, frequency or space features of the EEG signals. For this reason, in this paper a coherence-based EEG study is proposed during locomotion that along with the graph theory allows to establish spatio-temporal parameters that are characteristic in this study. The results show that along with the temporal features of the signal it is possible to find spatial patterns in order to classify motion tasks of interest. In this manner, the connectivity analysis alongside graphs provides reliable information about the spatio-temporal characteristics of the neural activity, showing a dynamic pattern in the connectivity during locomotions tasks.

Resumen: Una de las aplicaciones de las interfaces cerebro máquina (BMI, por las siglas en Inglés de brain machine interface) que en la actualidad han tenido mucho interés es el control de dispositivos de asistencia en rehabilitación de patologías neuromotrices. Esto es, que los dispositivos (prótesis, órtesis o exoesqueletos) tengan la capacidad de ejecutar la intención de movimiento del usuario, a través de la interpretación de las señales electroencefalográficas (EEG). Dicha interpretación se basa en el conocimiento de características en diferentes dominios de la señal EEG i.e., el dominio del tiempo, de la frecuencia o del espacio. Por tal motivo, en este trabajo proponemos un estudio sobre la coherencia de las señales EEG durante actividades de locomoción que, por medio de la teoría de grafos, nos permita establecer parámetros espacio-temporales característicos de las actividades motrices propuestas. Los resultados muestran que, además de las características temporales de la señal, es posible encontrar patrones espaciales que ayuden a clasificar las tareas motrices de interés. Esto es, el análisis de conectividad complementado con sus grafos asociados proporciona información confiable sobre las características espacio-temporales de la actividad neural, reflejando la dinámica de sus ajustes en correspondencia con distintos niveles de conectividad durante la marcha.

Incidence of osmophilic yeasts and Zygosaccharomyces rouxii during the production of concentrate grape juices.

Zygosaccharomyces rouxii is the main spoilage yeast of grape juice concentrates. Detection and identification of Z. rouxii during the production of grape juice concentrate is critical to prevent spoilage in the final product. In this work, three grape juice concentrate processing plants were assessed by identifying osmophilic yeasts in juices and surfaces during different stages of a complete production line. Subsequently, molecular typing of Z. rouxii isolates was done to determine the strain distribution of this spoilage yeast. Osmotolerant yeast species, other than Z. rouxii, were mainly recovered from processing plant environments. Z. rouxii was only isolated from surface samples with grape juice remains. Z. rouxii was largely isolated from grape juice samples with some degree of concentration. Storage of grape juice pre-concentrate and concentrate allowed an increase in the Z. rouxii population. A widely distributed dominant molecular Z. rouxii pattern was found in samples from all three processing plants, suggesting resident microbes inside the plant.

The Suprachiasmatic Nucleus Modulates the Sensitivity of Arcuate Nucleus to Hypoglycemia in the Male Rat.

The suprachiasmatic nucleus (SCN) and arcuate nucleus (ARC) have reciprocal connections; catabolic metabolic information activates the ARC and inhibits SCN neuronal activity. Little is known about the influence of the SCN on the ARC. Here, we investigated whether the SCN modulated the sensitivity of the ARC to catabolic metabolic conditions. ARC neuronal activity, as determined by c-Fos immunoreactivity, was increased after a hypoglycemic stimulus by 2-deoxyglucose (2DG). The highest ARC neuronal activity after 2DG was found at the end of the light period (zeitgeber 11, ZT11) with a lower activity in the beginning of the light period (zeitgeber 2, ZT2), suggesting the involvement of the SCN. The higher activation of ARC neurons after 2DG at ZT11 was associated with higher 2DG induced blood glucose levels as compared with ZT2. Unilateral SCN-lesioned animals, gave a mainly ipsilateral activation of ARC neurons at the lesioned side, suggesting an inhibitory role of the SCN on ARC neurons. The 2DG-induced counterregulatory glucose response correlated with increased ARC neuronal activity and was significantly higher in unilateral SCN-lesioned animals. Finally, the ARC as site where 2DG may, at least partly, induce a counterregulatory response was confirmed by local microdialysis of 2DG. 2DG administration in the ARC produced a higher increase in circulating glucose compared with 2DG administration in surrounding areas such as the ventromedial nucleus of the hypothalamus (VMH). We conclude that the SCN uses neuronal pathways to the ARC to gate sensory metabolic information to the brain, regulating ARC glucose sensitivity and counterregulatory responses to hypoglycemic conditions.

Molecular characterization of an inhibitor of NF-κB in the scallop Argopecten purpuratus: First insights into its role on antimicrobial peptide regulation in a mollusk.

Inhibitors of nuclear factor kappa B (IκBs) are major control components of the Rel/NF-κB signaling pathway, a key regulator in the modulation of the expression of immune-related genes in vertebrates and invertebrates. The activation of the Rel/NF-κB signaling pathway depends largely in the degradation of IκB proteins and thus, IκBs are a main target for the identification of genes whose expression is controlled by Rel/NF-κB pathway. In order to identify such regulation in bivalve mollusks, the cDNA sequence encoding an IκB protein was characterized in the scallop Argopecten purpuratus, ApIκB. The cDNA sequence of ApIκB is comprised of 1480 nucleotides with a 1086 bp open reading frame encoding for 362 amino acids. Bioinformatics analysis showed that ApIκB displays the conserved features of IκB proteins. The deduced amino acid sequence consists of a 39.7 kDa protein, which has an N-terminal degradation motif, six ankyrin repeats and a C-terminal phosphorylation site motif. Phylogenetic analysis revealed a high degree of identity between ApIκB and other IκBs from mollusks, but also to arthropod cactus proteins and vertebrate IκBs. Tissue expression analysis indicated that ApIκB is expressed in all examined tissues and it is upregulated in circulating hemocytes from scallops challenged with the pathogenic Gram-negative bacterium Vibrio splendidus. After inhibiting ApIκB gene expression using the RNA interference technology, the gene expression of the antimicrobial peptide big defensin was upregulated in hemocytes from non-challenged scallops. Results suggest that ApIκB may control the expression of antimicrobial effectors such as big defensin via a putative Rel/NF-κB signaling pathway. This first evidence will help to deepen the knowledge of the Rel/NF-κB conserved pathway in scallops.

Pro-inflammatory caspase-1 activation during the immune response in cells from rainbow trout Oncorhynchus mykiss (Walbaum 1792) challenged with pathogen-associated molecular patterns.

In response to pathogens, the higher vertebrate innate immune system activates pro-inflammatory caspase-1 which is responsible for the processing and secretion of several important cytokines involved in the host's defence against infection. To date, caspase-1 has been described in few teleost fish, and its activity has been demonstrated through substrate cleavage and inhibition by pharmacological agents. In this study, the detection of the active form of caspase-1 during the immune response in salmonid fish is described, where two antibodies were produced. These antibodies differentially recognize the structural epitopes of the inactive pro-caspase-1 and the processed active form of the caspase. Firstly, caspase-1 activation was demonstrated in vitro by ELISA, Western blotting and immunocytochemistry in rainbow trout macrophages exposed to different pathogen-associated molecular patterns plus the pathogen Aeromonas hydrophila. This activity was clearly abrogated by a caspase inhibitor and seems to be unrelated to IL-1ß secretion. Caspase-1 activation was then validated in vivo in gill cells from fish challenged with Aeromonas salmonicida. These results represent the first demonstration of caspase-1 activation in salmonids, and the first evidence of the putative regulatory role which this protease plays in inflammatory response in this fish group, as described for some other teleosts and mammals.

Effects of pH and sugar concentration in Zygosaccharomyces rouxii growth and time for spoilage in concentrated grape juice at isothermal and non-isothermal conditions.

The effect of pH (1.7-3.2) and sugar concentration (64-68 °Brix) on the growth of Zygosaccharomyces rouxii MC9 using response surface methodology was studied. Experiments were carried out in concentrated grape juice inoculated with Z. rouxii at isothermal conditions (23 °C) for 60 days. pH was the variable with the highest effect on growth parameters (potential maximum growth rate and lag phase duration), although the effect of sugar concentration were also significant. In a second experiment, the time for spoilage by this microorganism in concentrated grape juice was evaluated at isothermal (23 °C) and non-isothermal conditions, in an effort to reproduce standard storage and overseas shipping temperature conditions, respectively. Results show that pH was again the environmental factor with the highest impact on delaying the spoilage of the product. Thereby, a pH value below 2.0 was enough to increase the shelf life of the product for more than 60 days in both isothermal and non-isothermal conditions. The information obtained in the present work could be used by producers and buyers to predict the growth and time for spoilage of Z. rouxii in concentrated grape juice.

Probabilistic model for the spoilage wine yeast Dekkera bruxellensis as a function of pH, ethanol and free SO2 using time as a dummy variable.

The present study uses a probabilistic model to determine the growth/no growth interfaces of the spoilage wine yeast Dekkera bruxellensis CH29 as a function of ethanol (10-15%, v/v), pH (3.4-4.0) and free SO2 (0-50 mg/l) using time (7, 14, 21 and 30 days) as a dummy variable. The model, built with a total of 756 growth/no growth data obtained in a simile wine medium, could have application in the winery industry to determine the wine conditions needed to inhibit the growth of this species. Thereby, at 12.5% of ethanol and pH 3.7 for a growth probability of 0.01, it is necessary to add 30 mg/l of free SO2 to inhibit yeast growth for 7 days. However, the concentration of free SO2 should be raised to 48 mg/l to achieve a probability of no growth of 0.99 for 30 days under the same wine conditions. Other combinations of environmental variables can also be determined using the mathematical model depending on the needs of the industry.

Efecto preventivo de los agentes desensibilizantes en pacientes con indicaciones de raspado y alisado radicular / Preventive effect of desensitizing agents on patients with indications of scaling and root planning treatment

La hipersensibilidad dentinaria (HD) posterior al raspado y alisado radicular (RAR) ha sido poco estudiada desde una perspectiva preventiva a pesar de su relevancia clínica. El objetivo de esta investigación fue evaluar el efecto de las cremas desensibilizantes en pacientes con indicaciones de raspado y alisado radicular. Para ello, se realizó un estudio longitudinal cuasi-experimental con una muestra no probabilística de 18 pacientes (hombres y mujeres) entre 20 y 50 años de edad, que requerían tratamiento con RAR en dientes posteriores (premolares y primer molar), quienes fueron asignados al azar en cada uno de los tres grupos a evaluar. Las cremas desensibilizantes utilizadas en esta investigación contienen citrato de potasio, nitrato de potasio, fluoruro de sodio y triclosan estas se indicaron un mes antes de realizar los RAR en todos los grupos. Para medir la presencia de hipersensibilidad dentinaria se aplicaron estímulos táctiles y térmicos a los 8, 15 y 22 días posteriores al tratamiento de RAR y se usó la Escala Visual Análoga Graduada (EVAG) para evaluar el dolor. Como resultado se obtuvo menor presencia de HD en el grupo que utilizó citrato de potasio 5.04% y monofluorfosfato 1.1%, aun cuando en los tres grupos se observó disminución de HD durante los tres periodos de medición. Llegando a la conclusión que es pertinente prescribir cremas desensibilizantes con citrato de potasio 5.04% y monofluorfosfato 1.1% a los pacientes con necesidades clínicas similares a los de este estudio un mes antes de planificar los RAR.

The presence of dentine hypersensitivity (DH) after scaling and root planning treatment (RPT) has been scarcely studied from a preventive perspective in spite the clinical relevance of the issue. The aim of this research was to evaluate the preventive effect of some desensitizing dentifrices in patients previous to a RPT. In this sense, a cuasi-experimental, longitudinal study was performed. The non probabilistic sample was constituted by 18 patients (women and men) aged between 20 and 50; all of them diagnosed as requiring scaling and root planning treatment for posterior teeth (premolars and first molars). Subjects were randomly assigned to one of the three groups. The desensitizing toothpaste used in the study contained potassium citrate, potassium nitrate, sodium fluoride and triclosan. These paste were prescribed for patients a month before the RPT. Dentine hypersensitivity was evaluated by using tactile and thermal stimuli applied 8, 25 and 22 days after RPT; the Visual Analogue Scale (VSA) was used to assess pain. Results showed lower presence DH in the 5.04% potassium citrate group and 1.1% monofluor fosfate, even when there was a decrease of DH for the three measurement periods. It was concluded that it would be good to prescribe 5.04% potassium citrate group and 1.1% monofluorfosfate desensitizing agents to patients with clinical needs similar to the ones described in this study, a month before the RPT.

Regeneración tisular guiada para recubrimiento radicular con biomateriales dentales: reporte de un caso / Guided tissue regeneration with dental biomaterials for root coverage: a case report

Los biomateriales son sustancias naturales, sintéticas o una combinación de ambas que sustituyen partes u órganos completos del cuerpo humano con una apropiada respuesta por parte del hospedador basado en los principios de biocompatibilidad y biofuncionalidad; la periodoncia como parte de las ciencias médicas se beneficia del uso y aplicación de los mismos para mejorar y simplificar los resultados de la reparación de tejidos, teniendo como meta principal la regeneración de éstos. Por su versatilidad y buenos resultados, los injertos gingivales son los procedimientos más usados dentro de la práctica clínica para recubrir raíces denudadas; sin embargo, requieren de tejidos donantes, por lo que se afectan dos sitios quirúrgicos. Cuando dentro de los diferentes tipos de tratamientos se cuenta con biomateriales que pueden sustituir esos tejidos donantes y lograr resultados similares, se puede simplificar entonces el acto quirúrgico y el post operatorio del paciente. Este artículo muestra como la combinación del Apafill-G, el Membracel y el Tisuacryl®, fueron efectivos en el tratamiento de dos recesiones periodontales bilaterales de los dientes 13 y 23 en un paciente de 35 años, con antecedentes de buena salud, que fue tratado en la Clínica Estomatológica de Varadero mediante la técnica quirúrgica de regeneración tisular guiada, utilizada para lograr recubrimiento radicular. La realización de la misma simplificó el procedimiento, sin la necesidad de extracción de tejidos donadores, se logró una cantidad adecuada de tejido adherido coronal y una cobertura radicular completa , sin que estuvieran presentes las molestias post operatorias comunes que se generan cuando se utilizan injertos gingivales

Biomaterials are natural substances, synthetic or a combination of both to replace parts or whole organs of the human body with an appropriate response by the host based on the principles of biocompatibility and biofunctionality, periodontics as part of medical science benefits from the use and applying them to improve and simplify the results of tissue repair, having as main goal the regeneration of these. Because of its versatility and good results, gingival grafts are the procedures used in clinical practice to cover denuded roots, however, require donor tissue, so it involved two surgical sites. When within the different types of treatments with biomaterials that can replace those tissues donors and achieve similar results, then you can simplify the surgery and the postoperative patient. This article shows how the combination of Apafill-G, and MEMBRACEL Tisuacryl ® were effective in the treatment of periodontal recessions bilateral two teeth 13 and 23 in a 35 year old patient with a history of good health, which was treated Dental Clinic in Varadero by the surgical technique of guided tissue regeneration, used to achieve root coverage. The simplified embodiment of the same procedure, without the need for removal of tissue donors, was obtained an adequate amount of adhering tissue and coronal complete root coverage, without the presence common postoperative discomfort generated when using gingival grafts

Factors influencing combined exposure to three indicator polychlorinated biphenyls in an adult cohort from Bolivia.

Polychlorinated biphenyls are persistent organic pollutants that have been used for decades in several industrial applications. Although production of polychlorinated biphenyls was restricted from the 1970s in most countries, substantial amounts remain in old equipment and buildings and they have been detected in various environmental and biological matrices. The main objective of this study was to analyze predictors of the combined exposure to three non-dioxin-like polychlorinated biphenyls (congeners 138, 153 and 180) in serum and adipose tissue from an adult cohort (n=112) living in the city of Santa Cruz de la Sierra (Bolivia) and surrounding towns/villages. A second aim was to identify modifiers that might influence the statistical associations found, using crude, partially-adjusted, and global multiple linear regression models. Main predictors of serum concentrations were occupation and fatty food consumption, while those for adipose tissue concentrations included age, smoking habit, fatty food consumption, and residence. The differences between the two matrices might be derived from their biological meaning, given that adipose tissue concentrations are an indicator of chronic exposure to polychlorinated biphenyls while serum levels are a good predictor of ongoing exposure and the mobilization of polychlorinated biphenyls stored in fatty tissues. Body mass index was found to be an important modifier of these associations.

Development of a new antibody for detecting natural killer enhancing factor (NKEF)-like protein in infected salmonids.

The main cellular responses of innate immunity are phagocytic activity and the respiratory burst, which produces a high amount of reactive oxygen species. Natural killer enhancing factor (NKEF) belongs to the peroxiredoxin family that has an antioxidant function and enhances cytotoxic cell activity. This molecule may play a key role in macrophage and cytotoxic cell communication during the innate immune response of fish against pathogens. In fish, the NKEF gene has been characterized in some species as showing an up-regulation in infected fish, suggesting a trigger effect upon NK-like cells. To detect and localize this molecule in salmonids at protein level, a monospecific polyclonal antibody was generated. A probable NKEF-like protein epitope region was identified and characterized using bioinformatic tools, and the sequence was chemically synthesized using Fmoc strategy, analysed by RP-HPLC and its molecular weight confirmed by mass spectrometry. The synthetic peptide was immunized and antibodies from ascitic fluid were obtained. The resulting antibody is a versatile tool for detecting NKEF by different immune techniques such as ELISA, Western blotting and immunohistochemistry. Analysis of NKEF-like protein is a useful method for characterizing immune properties of this molecule in fish during response to pathogens.

Contribution of sociodemographic characteristics, occupation, diet and lifestyle to DDT and DDE concentrations in serum and adipose tissue from a Bolivian cohort.

The organochlorine pesticide p,p'-Dichlorodiphenyltrichloroethane (DDT) was widely used in the early 1960s-70s for vector control in tropical and subtropical areas of South America. Due to its persistence, DDT has a high potential to bioaccumulate in the food chain and living organisms and is a major public health concern, especially in South America. The main purpose of the present study was to investigate predictors of serum and adipose tissue concentrations of p,p'-DDT and its main metabolite, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), in an adult cohort (n=112) from Santa Cruz de la Sierra, Bolivia, using multiple linear regression models. These models explained 29.3-47.8% of the variability in adipose tissue concentrations of p,p'-DDT and p,p'-DDE, respectively, and 32.9-47.0% of that in serum. Main exposure predictors included age, occupational class, residence, diet, smoking habit, and accumulated breastfeeding time. This is one of the few studies to explore predictors of human exposure to these chemicals using a multivariate approach in a South American population. Results show that predictors of human exposure to p,p'-DDT and p,p'-DDE in Santa Cruz de la Sierra may diverge from those found in other populations of the world, due to particular sociodemographic and lifestyle characteristics of this region.

Concentrations of organochlorine pesticides and polychlorinated biphenyls in human serum and adipose tissue from Bolivia.

Organochlorine pesticides and polychlorinated biphenyls (PCBs) are synthetic chemicals that are highly resistant to biodegradation and have proven adverse health effects. The objectives of this study were to determine concentrations of three selected organochlorine pesticides (p,p'-DDT, p,p'-DDE, HCB) and three specific PCB congeners (PCB 138, 153, 180) in adipose tissue and serum samples from an urban adult population (n=112) in the city of Santa Cruz de la Sierra, Bolivia, and to investigate their relationships within and between the two matrices and with selected socio-demographic characteristics. The percentages of samples positive for these compounds ranged from 40% for PCB 180 to 100% for p,p'-DDE in adipose tissue, and from 21% for HCB to 93% for p,p'-DDE in serum. Median number of residues per sample was five for adipose tissue and three for serum. Geometric mean concentrations indicate a considerable historical and recent exposure to organochlorine pesticides and PCBs in this population. Adipose tissue:serum ratios ranged from 149.3 to 590.3 (wet basis) and from 0.9 to 3.5 (lipid basis). We found positive and statistically significant correlations between adipose tissue and serum concentrations only in p,p'-DDE and HCB. This novel study in Bolivia underlines the need for human biomonitoring to assess exposure to environmental pollutants in South America.

Viral hemorrhagic septicaemia virus (VHSV) up-regulates the cytotoxic activity and the perforin/granzyme pathway in the rainbow trout RTS11 cell line.

A survey of immune-relevant genes that might be up-regulated in response to viral hemorrhagic septicaemia virus (VHSV) in the rainbow trout monocyte-macrophage cell line, RTS11, unexpectedly revealed an increased expression of perforin (PRF) and granzyme (GRZ) genes, which represent components of the major cytotoxic pathway. The natural killer-enhancing factor (NKEF), also known to modulate cytotoxic activity, was up-regulated at the gene but strikingly down-regulated at protein level. The expression of these genes was not affected in head kidney leukocytes (HKLs) infected with VHSV, leading us to evaluate the potential cytotoxic activity of RTS11 and HKLs. For the first time, the cytotoxic activity of RTS11 against xenogeneic targets has been demonstrated, although this was modest relative to HKLs. Yet the activity in RTS11 was significantly increased by VHSV, as in HKLs. This cytotoxic activity elicited by viral infection appeared to require viral gene expression because inactivated VHSV failed to increase RTS11 cytotoxic activity. As for other immune functions, RTS11 cells provide a model for further studying cytotoxic activities of fish monocyte-macrophages.