Effect of ionizing radiation on human myeloperoxidase: Reaction with hydrated electrons.

Myeloperoxidase (MPO) is a myeloid-lineage restricted enzyme largely expressed in the azurophilic granules of neutrophils. It catalyses the formation of reactive oxygen species, mainly hypochlorous acid, contributing to anti-pathogenic defense. Disorders in the production or regulation of MPO may lead to a variety of health conditions, mainly of inflammatory origin, including autoimmune inflammation. We have studied the effect of ionizing radiation on the activity of MPO, as measured by the capacity retained by the enzyme to produce hypochlorous acid as reactive oxygen species after exposure to successive doses of solvated electrons, the strongest possible one-e- reducing agent in water. Chlorination activity was still present after a very high irradiation dose, indicating that radiation damage does not take place at the active site, hindered in the core of MPO structure. Decay kinetics show a dependence on the wavelength, supporting that the process must occur at peripheral functional groups situated on external and readily accessible locations of the enzyme. These results are relevant to understand the mechanism of resistance of our innate anti-pathogenic defense system and also to get insight into potential strategies to regulate MPO levels as a therapeutic target in autoimmune diseases.

Construcción y validación de un cuestionario para medir función gastrointestinal en adultos / Construction and validation of a questionnaire to measure gastrointestinal function in adults

INTRODUCCIÓN: La función gastrointestinal puede alterarse por distintas circunstancias clínicas o por efectos secundarios de algún tratamiento, tal es el caso de los pacientes oncológicos, ya sea por la localización del tumor en el aparato digestivo o por los efectos que produce la quimioterapia, la radioterapia o la cirugía y manifestarse con síntomas que pueden poner en riesgo el estado de nutrición. OBJETIVO: Por la importancia de evaluar la función gastrointestinal el objetivo de este estudio fue crear y validar un cuestionario que permita medirla en población adulta. MATERIAL Y MÉTODOS: La construcción del cuestionario se basó en la realización de distintas versiones que se fueron modificando después de la opinión y observaciones de parte un panel de expertos y de un pilotaje a 100 pacientes con cáncer. La validación se basó en la aplicación del cuestionario a 898 personas con y sin cáncer; para analizar la validez se utilizó Análisis factorial exploratorio y para la confiabilidad Alpha de Cronbach. RESULTADOS: La versión final quedó compuesta por 9 ítems que miden tanto los síntomas gastrointestinales como el ritmo intestinal. Se obtuvo el valor KMO de 0.850 y la prueba de Esfericidad de Bartlett de 2914.41 (gl. de 36). La extracción de los factores mediante el método de Componentes Principales distribuyó a los 9 ítems en 2 dimensiones con pesos factoriales ≥ 0.40, los cuales representan una varianza acumulada del 58.89%. En cuanto a la confiabilidad, se determinó por el análisis de Alpha de Cronbach, para el total del instrumento (9 ítems) y se obtuvo un valor de 0.844. CONCLUSIONES: El diseño de este cuestionario permite conocer la función gastrointestinal en personas adultas ya que identifica el nivel de gravedad de los síntomas gastrointestinales. Los niveles de confiabilidad nos aseguran que el cuestionario valora adecuadamente la función gastrointestinal

INTRODUCTION: Gastrointestinal function can be altered by different clinical circumstances, for example side effects of a treatment. In cancer patients, the gastrointestinal function is modified either due to the location of the tumor in the digestive system or by the side effects of chemotherapy, radiotherapy or surgery. This can be manifested with symptoms that could be a nutritional risk. AIM: To create and validate a questionnaire to measure gastrointestinal function in adults. MATERIAL AND METHODS: The construction of the questionnaire was based on different versions. The questionnaire was modified after the opinion and observations of expert panels and a pilot study of 100 patients with cancer. The validation was performed based on the application of the questionnaire to 898 participants. For the statistical analysis Cronbach's Alpha and Exploratory Factor analysis was performed. RESULTS: The final version of the questionnaire was integrated with 9 items that measure both gastrointestinal symptoms and intestinal rhythm. The KMO value was 0.850 and Bartlett's Sphericity test was 2914.41 (gl. of 36). The extraction of the factors by Principal Components Analysis distributed the 9 items in 2 dimensions with factors ≥ 0.40, which represent an accumulated variance of 58.89%. About trustworthy was determined by Cronbach's Alpha analysis, for the total 9 items the value obtained was 0.844. CONCLUSIONS: The design of this questionnaire allows to measure the gastrointestinal function in adults, also the identification of the level of severity of the gastrointestinal symptoms. The confidence levels assure that the questionnaire assess the gastrointestinal function adequately

Effect of parenteral glutamine in patients with gastrointestinal cancer undergoing surgery / Efecto de la glutamina parenteral en pacientes con cáncer gastrointestinal sometidos a cirugía

Background and objective: malnutrition during cancer treatment is common in patients; therefore, nutritional intervention has an important role in cancer prognosis. Total parenteral nutrition is indicated for patients subjected to a major surgery with gastrointestinal complications. Nutritional support could be improved with glutamine (Gln). Therefore, in this work, the effect of parenteral glutamine in patients with gastrointestinal cancer undergoing surgery was studied. Material and methods: patients were classifi ed into two groups: non-supplemented and supplemented (Gln; 0.4 g/kg/day). Both groups received parenteral nutrition. One and seven days after surgery the nutritional status was evaluated. Hematic cytometry, protein metabolism and biochemical data were analyzed. A questionnaire was also applied to assess gastrointestinal function. Results: after the intervention, the nutritional status in both groups improved. However, the nutritional condition improved signifi cantly better (p = 0.008) in the supplemented group. According to the gastrointestinal function evaluation, the supplemented group changed from severe to mild dysfunction (p = 0.0001). The non-supplemented group progressed from moderate to severe dysfunction, but no changes in blood cell markers were observed. The supplemented group improved its concentration of lymphocytes (p = 0.014). The plasma albumin concentration did not change in groups, but prealbumin improved signifi cantly (p = 0.012) in the group that was supplemented with Gln. Conclusion: intravenous nutritional support supplemented with glutamine can improve gastrointestinal function, improving the absorption of nutrients, which leads to a better state of nutrition. It also has positive effects on plasma concentration of lymphocytes, monocytes and prealbumin

Introducción y objetivo: los pacientes con cáncer desarrollan desnutrición durante el tratamiento antineoplásico, es por ello que el soporte nutricio tiene un rol importante. La nutrición parenteral es el soporte indicado para pacientes que fueron sometidos a cirugía con complicaciones gastrointestinales; este soporte puede ser suplementado con glutamina. Evaluamos el efecto de la glutamina parenteral en pacientes con cáncer gastrointestinal sometidos a cirugía. Material y métodos: se aleatorizaron los pacientes en dos grupos. Ambos grupos recibieron nutrición parenteral, en un grupo no suplementada y en otro grupo suplementada con glutamina (0,4 g/kg/día). Las medidas se tomaron el día uno y el día siete posteriores a la cirugía; en ambas mediciones se evaluó el estado nutricional, se tomó una muestra sanguínea para analizar parámetros bioquímicos y se aplicó un cuestionario de función gastrointestinal. Resultados: después de la intervención, el estado nutricional mejoró en ambos grupos, sin embargo, en el grupo suplementado mejoró significativamente (p = 0,008). De acuerdo a la función gastrointestinal, el grupo suplementado progresó de disfunción severa a leve (p = 0,0001), mientras que el grupo no suplementado progresó de disfunción moderada a severa. En cuanto a los parámetros bioquímicos, no hubo cambios en el grupo no suplementado. En ambos grupos no hubo cambios en las concentraciones plasmáticas de albúmina. En el grupo suplementado mejoraron de manera significativa las concentraciones de linfocitos (p = 0,014) y prealbúmina (p = 0,012). Conclusión: el apoyo nutricio endovenoso suplementado con glutamina puede mejorar la función gastrointestinal, mejorando la absorción de nutrimentos, lo que conlleva a un mejor estado de nutrición. Asimismo, tiene efectos positivos en las concentraciones plasmáticas de linfocitos y monocitos y prealbúmina

El sentido de la vida en universitarios españoles / The meaning of life in Spanish university students

Presentamos un estudio en el que se propone un perfil del Sentido de la Vida en jóvenes universitarios. En el estudio participaron 1172 estudiantes de diferentes universidades españolas (888 mujeres, 284 hombres). Con una edad comprendida entre los 17 y más de 23 años. Se aplicaron el instrumento PIL (Purpose in Life) para la medición del Sentido de la Vida y un cuestionario complementario

We present a study in which proposed a profile of Meaning in Life in universities students. In this study participated 1172 students from different Spanish universities (888 women, 284 men). With an age between 17 and 23 years. Were applied the PIL (Purpose in Life) instrument for measuring the Meaning of Life and an additional questionnaire

Fondaparinux as a safe alternative for managing heparin-induced thrombocytopenia in postoperative cardiac surgery patients.

OBJECTIVE: Heparin-induced thrombocytopenia (HIT) is a rare but severe prothrombotic disorder of heparin treatment that leads to a decline in platelet count and thrombotic complications. If HIT is suspected, then heparin should be stopped and an alternative anticoagulant started. Fondaparinux is a factor Xa-inhibitor that is not FDA-approved for this condition, but preliminary experience in HIT patients has been reported in the literature. The present study describes an experience of anticoagulation management with fondaparinux in postoperative cardiac surgery patients. DESIGN: Retrospective study. SETTING: Tertiary hospital. PARTICIPANTS: Patients who had undergone cardiac surgery from October 2009 to June 2012. INTERVENTIONS: After HIT was suspected clinically, PaGIA and ELISA test were performed in all patients to diagnose HIT. In the patients included, anticoagulation was managed with a low dose of fondaparinux and daily monitoring of platelet count and anti-Xa level. MEASUREMENTS AND MAIN RESULTS: Of a total of 1,338 postoperative cardiac surgery patients, 15 patients were included (1.1%). Twelve of the 15 patients with HIT presented with renal failure and were under continuous renal replacement therapy. Two major bleeding events occurred during fondaparinux treatment, although platelet count and anti-Xa activity remained within the normal range. No thrombotic episodes were diagnosed. CONCLUSION: With daily monitoring of anti-Xa activity, fondaparinux appeared to be a good alternative to heparin in the study group; however, randomized clinical trials are needed to establish the safety and efficacy of this drug in critically ill, previously HIT patients.

Desarrollo y validación de una escala sobre disciplina parental en contextos familiares en situación de riesgo psicosocial / No disponible

Este artículo describe el desarrollo de una escala para evaluar las creencias de padres y madres en situación de riesgo psicosocial sobre las estrategias disciplinarias durante la adolescencia. Se presentan los resultados psicométricos obtenidos en el proceso de construcción de la escala con una investigación en la que participaron 197 familias usuarias de los servicios sociales comunitarios de la ciudad de Sevilla. Los análisis factoriales realizados (exploratorio y confirmatorio) evidenciaron la existencia de dos factores con índices estadísticos adecuados: disciplina inductiva y disciplina coercitiva. Con objeto de aportar evidencias de validez, se relacionaron estos dos factores con otras dimensiones del funcionamiento familiar teóricamente relacionadas con las prácticas disciplinarias, obteniéndose resultados que apoyan la validez y fiabilidad del instrumento desarrollado para evaluar un ámbito fundamental de las prácticas educativas de las familias en situación de riesgo psicosocial

Development and validation of an instrument for measuring parents’ beliefs about behavioral control as educative practices with adolescents in psychosocial risk situations is presented. The development and dimensionality of the proposed scale was examined with a sample made of 197 families at psychosocial risk that benefited from preservation services in Seville (Andalusia, Spain). Both exploratory and confirmatory factor analyses evidenced two factors with adequate psychometric properties: inductive discipline and coercive discipline. Evidences for validity were probed through significant correlations with other family functioning measures. The scale developed led us to evaluate a critical aspect of parental discipline in families at psychosocial risk with psychometric guarantees

Un análisis de los acontecimientos vitales estresantes durante la adolescencia / No disponible

El objetivo de este estudio fue analizar cuantitativa y cualitativamente el estrés psicosocial experimentado por una amplia muestra de adolescentes y explorar posibles diferencias en esta dimensión entre chicos y chicas. Los resultados obtenidos pusieron de manifiesto, en primer lugar, la relevancia de determinados eventos vitales estresantes durante la adolescencia, particularmente los relacionados con el ámbito escolar y familiar. En segundo lugar, se observó tanto la existencia de un patrón compartido en el modo en que chicos y chicas experimentan estrés psicosocial durante la adolescencia, como algunas diferencias significativas entre unos y otras, en cuanto al tipo de situaciones más frecuentes y el impacto emocional con que se viven (AU)

The aim of this study was to examine stressful life events -in a quantitative and a qualitative manner- using a large adolescent sample. Additionally, we explored possible differences between girls and boys in how they deal with psychosocial stress. Firstly, results showed that school and family contexts were the main causes of stressful events in adolescence. Secondly, data analysis revealed a similar pattern in how girls and boys manage psychosocial stress during adolescence, but there were also significant differences in particular events, in relation to both their frequency and their emotional impact (AU)

Perfil psicosocial de familias en situación de riesgo. Un estudio de necesidades con usuarias de los Servicios Sociales Comunitarios por razones de preservación familiar / Psychosocial characteristics of families at risk. A need study with women user of Social and Community Services in order to family preservation

En este artículo se presenta un estudio de necesidades realizado con una muestra de madres usuarias de los Servicios Sociales Comunitarios que reciben intervenciones de cara a la preservación familiar. Los resultados obtenidos nos permiten ofrecer una aproximación del perfil psicosocial de estas familias y, al mismo tiempo, reflexionar sobre las características que pueden optimizar la eficacia de las intervenciones que con ellas se llevan a cabo desde los Servicios Sociales Comunitarios (AU)

In this article we present a need study carried out with a sample of mothers users of Social and Community Services receiving family preservation interventions. Results obtained show the main characteristics of these families, and also are useful in order to define how to improve social intervention developed by Social and Community Services with these families (AU)

La intervención con familias en situación de riesgo psicosocial. Aportaciones desde un enfoque psicoeducativo / No disponible

La intervención con las familias en situación de riesgo ha cambiando mucho en lasúltimas décadas. De una intervención de marcado carácter asistencial y basada en la teoríadel déficit, se ha evolucionado a formas de atención y actuación mucho más positivas,preventivas y encaminadas a la preservación y el fortalecimiento familiar. Dentro de estavisión actual de la intervención familiar se enmarcan los programas psicoeducativos paramadres y padres, cuyas principales características son descritas en este artículo. Comoejemplo de este tipo de intervenciones se presenta el programa de Formación y ApoyoFamiliar para familias en situación de riesgo. Se trata de un programa de corte psicoeducativoy comunitario, inscrito dentro de las actuaciones que actualmente se llevana cabo con las familias en situación de riesgo que son atendidas por Servicios SocialesComunitarios del Ayuntamiento de Sevilla(AU)

The intervention with at-risk families has changed greatly over recent decades. Thus,an intervention mainly welfare and deficit has advanced to a prevention interventionthat aims to strengthen and preserve families. In this approach are framed the parentpsychoeducational programs, whose main characteristics are exposed in this paper. Asample of this kind of prevention intervention for parent is the family program coordinatedby Social Services at Seville Council. “Training and Family Support Program”is for at-risk families who received a psychosocial intervention by Social Service forfamily preservation reason(AU)

In vitro susceptibilities of bloodstream isolates of Candida spp: results from a multicenter active surveillance program in Andalusia

Objetivos: Determinar la sensibilidad antifúngica de las cepas de Candida spp. aisladas en sangre en Andalucía, obtenidas en un estudio prospectivo multicéntrico realizado entre octubre de 2005 y septiembre de 2006. Métodos: Se aislaron 197 cepas de Candida spp. Las CMIs de anfotericina B, fluconazol, itraconazol y voriconazol se realizaron usando el panel de Sensititre YeastOne. Las CMIs de posaconazol y caspofungina se determinaron por Etest. Resultados: C. albicans (..) (AU)

Objectives The aim of this study was to determine the antifungal drug susceptibilities of Candida bloodstream isolates in Andalusia, obtained through a multicenter active laboratory-based surveillance between October 2005 and September 2006.MethodsOne hundred and ninety-seven Candida isolates were collected. The MICs of amphotericin B, fluconazole, itraconazole and voriconazole were established using the Sensititre Yeast One panel. The MICs of posaconazole and caspofungin were determined by Etest. Results C. albicans was the most frequently isolated species (49.2%), followed (..) (AU)

A theoretical study on the mechanism of the base-promoted decomposition of N-chloro,N-methylethanolamine.

The first step of the base-promoted decomposition of N-chloro,N-methylethanolamine in aqueous solution (CH3N(Cl)CH2CH2OH + HO- --> imine + Cl- + H2O (+ CH2O) --> amine + aldehyde) is investigated at the MP2/6-31++G(d,p) computing level. Solvation is included by using both a microsolvated model, in which two explicit water molecules simulate the specific solvent effects, and a hybrid cluster-continuum model, by applying a polarized continuum on the previous results, to account for the bulk effect of the solvent. Four alternative pathways (bimolecular fragmentation, Hofmann, Zaitsev and intramolecular eliminations) are possible for the rate-limiting step of this base-promoted decomposition. These reactive processes are bimolecular asynchronous concerted reactions. The common feature of the four pathways is the proton transfer to HO- being more advanced than all other molecular events, whereas imine formation is delayed. Non-reactive cyclic arrangements involving one of the explicit water molecules are found at transition structures of Hofmann and Zaitsev eliminations, such water molecule acting both as H+ donor and acceptor. Although MP2 calculations misjudge the absolute activation Gibbs free energy values, this computational level adequately predicts the enhancement in the decomposition rate due to the presence of the -OH group.

In vitro susceptibilities of bloodstream isolates of Candida spp.: results from a multicenter active surveillance program in Andalusia.

OBJECTIVES: The aim of this study was to determine the antifungal drug susceptibilities of Candida bloodstream isolates in Andalusia, obtained through a multicenter active laboratory-based surveillance between October 2005 and September 2006. METHODS: One hundred and ninety-seven Candida isolates were collected. The MICs of amphotericin B, fluconazole, itraconazole and voriconazole were established using the Sensititre YeastOne panel. The MICs of posaconazole and caspofungin were determined by Etest. RESULTS: C. albicans was the most frequently isolated species (49.2%), followed by C. parapsilosis (17.3%), C. tropicalis (15.2%), C. glabrata (13.7%) and C. krusei (3.6%). All strains were inhibited at MICs of or = 64 mg/L) and 7 (3.6%) were considered resistant to itraconazole (MIC > or = 1 mg/L). All the isolates were susceptible to voriconazole and caspofungin. CONCLUSION: In our study C. krusei and C. glabrata were identified in over 18% of cases of candidemia. Most clinical isolates of these species are resistant or susceptible-dose-dependent to fluconazole but susceptible to voriconazole and caspofungin. These agents must be used in the empiric treatment of candidemia rather than fluconazole.

Nucleotide polymorphism and phenotypic associations within and around the phytochrome B2 Locus in European aspen (Populus tremula, Salicaceae).

We investigated the utility of association mapping to dissect the genetic basis of naturally occurring variation in bud phenology in European aspen (Populus tremula). With this aim, we surveyed nucleotide polymorphism in 13 fragments spanning an 80-kb region surrounding the phytochrome B2 (phyB2) locus. Although polymorphism varies substantially across the phyB2 region, we detected no signs for deviations from neutral expectations. We also identified a total of 41 single nucleotide polymorphisms (SNPs) that were subsequently scored in a mapping population consisting of 120 trees. We identified two nonsynonymous SNPs in the phytochrome B2 gene that were independently associated with variation in the timing of bud set and that explained between 1.5 and 5% of the observed phenotypic variation in bud set. Earlier studies have shown that the frequencies of both these SNPs vary clinally with latitude. Linkage disequilibrium across the region was low, suggesting that the SNPs we identified are strong candidates for being causally linked to variation in bud set in our mapping populations. One of the SNPs (T608N) is located in the "hinge region," close to the chromophore binding site of the phyB2 protein. The other SNP (L1078P) is located in a region supposed to mediate downstream signaling from the phyB2 locus. The lack of population structure, combined with low levels of linkage disequilibrium, suggests that association mapping is a fruitful method for dissecting naturally occurring variation in Populus tremula.

Myeloperoxidase-catalyzed chlorination: the quest for the active species.

Myeloperoxidase (MPO) is a dominating enzyme of circulating polymorphonuclear neutrophils that catalyzes the two-electron oxidation of chloride, thereby producing the strong halogenating agent hypochlorous acid (ClO(-)/HOCl). In absence of MPO the tripeptide Pro-Gly-Gly reacts with HOCl faster than the amino acid taurine (2-aminoethanesulfonic acid, Tau), while the MPO-mediated chlorination shows reverse order. A comparative study of the enzymatic oxidation of both substrates at pH 4.0-6.0, varying H2O2 concentration is presented. Initial and equilibrium rates studies have been carried on, reaction rates in the latter being slower due to the chemical equilibrium between MPO-I and MPO-II-HO2. A maximum of chlorination rate is observed for Pro-Gly-Gly and Tau when [H2O2] approximately 0.3-0.7 mM and pH approximately 4.5-5.0. Several mechanistic possibilities are considered, the proposed one implies that chlorination takes place via two pathways. One, for bulkier substrates, involves chlorination by free HOCl outside the heme cavity; ClO(-) is released from the active center, diffuses away the heme cavity, and undergoes protonation to HOCl. The other implies the existence of compound I-Cl(-) complex (MPO-I-Cl), capable of chlorinating smaller substrates in the heme pocket. Electronic structure calculations show the size of Pro-Gly-Gly comparable to the available gap in the substrate channel, this tripeptide being unable to reach the active site, and its chlorination is only possible by free HOCl outside the enzyme.

Un análisis de los acontecimientos vitales estresantes durante la adolescencia / No disponible

El objetivo de este estudio fue analizar cuantitativa y cualitativamente el estréspsicosocial experimentado por una amplia muestra de adolescentes y explorar posiblesdiferencias en esta dimensión entre chicos y chicas. Los resultados obtenidos pusieronde manifiesto, en primer lugar, la relevancia de determinados eventos vitales estresantesdurante la adolescencia, particularmente los relacionados con el ámbito escolar y familiar.En segundo lugar, se observó tanto la existencia de un patrón compartido en el modoen que chicos y chicas experimentan estrés psicosocial durante la adolescencia, comoalgunas diferencias significativas entre unos y otras, en cuanto al tipo de situaciones másfrecuentes y el impacto emocional con que se viven

The aim of this study was to examine stressful life events –in a quantitative and aqualitative manner– using a large adolescent sample. Additionally, we explored possibledifferences between girls and boys in how they deal with psychosocial stress. Firstly,results showed that school and family contexts were the main causes of stressful eventsin adolescence. Secondly, data analysis revealed a similar pattern in how girls and boysmanage psychosocial stress during adolescence, but there were also significant differencesin particular events, in relation to both their frequency and their emotional impact

Evaluación del apoyo social mediante la escala ASSIS: descripción y resultados en una muestra de madres en situación de riesgo psicosocial / Evaluation of social support by means of the Scale ASSIS: description and results in a sample of mothers in situation of psychsocial risk

En el artículo presentamos algunos de los resultados obtenidos en un estudio realizadocon madres en situación de riesgo psicosocial. En concreto, se describen diversas dimensionesdel apoyo social de estas mujeres y las principales características de sus redes deapoyo. Asimismo, el artículo se ocupa de la escala utilizada para evaluar el apoyo socialy, de manera específica, se analiza su utilidad como instrumento de evaluación para losprofesionales de los Servicios Sociales

In this article we present some results obtained in a study carried out with mothers atpsychosocial risk. Both several sizes of social support and main characteristics of theirsocial networks are commented. In the article we also describe the instrument used inorder to assess social support and discuss its utility for professionals that work in the contextof Social Services

Clinal variation in phyB2, a candidate gene for day-length-induced growth cessation and bud set, across a latitudinal gradient in European aspen (Populus tremula).

The initiation of growth cessation and dormancy represents a critical ecological and evolutionary trade-off between survival and growth in most forest trees. The most important environmental cue regulating the initiation of dormancy is a shortening of the photoperiod and phytochrome genes have been implicated in short-day-induced bud set and growth cessation in Populus. We characterized patterns of DNA sequence variation at the putative candidate gene phyB2 in 4 populations of European aspen (Populus tremula) and scored single-nucleotide polymorphisms in an additional 12 populations collected along a latitudinal gradient in Sweden. We also measured bud set from a subset of these trees in a growth chamber experiment. Buds set showed significant clinal variation with latitude, explaining approximately 90% of the population variation in bud set. A sliding-window scan of phyB2 identified six putative regions with enhanced population differentiation and four SNPs showed significant clinal variation. The clinal variation at individual SNPs is suggestive of an adaptive response in phyB2 to local photoperiodic conditions. Three of four SNPs showing clinal variation were located in regions with excessive genetic differentiation, demonstrating that searching for regions of high genetic differentiation can be useful for identifying sites putatively involved in local adaptation.

Antioxidant defence of the neonatal rat brain against acute hyperammonemia.

Oxidative stress associated with the presence of elevated concentrations of ammonia in the brain has been proposed as one possible mechanism involved in ammonia toxicity. In a previous study [Brain Res.973 (2003) 31], we reported that neonatal rats are more resistant to acute ammonia toxicity than adult rats. In the present work, we studied the antioxidant status of the brain in hyperammonemic neonatal rats. Increased activities of the antioxidant enzymes and enhanced glutathione content were found in the brains of the hyperammonemic neonatal rats as compared to the controls. In addition, no changes in brain reactive oxygen species (ROS) levels and lipid peroxidation due to hyperammonemia were found. Therefore, acute ammonia intoxication does not induce oxidative stress in neonatal rats, a fact that may explain the resistance against hyperammonemia shown by neonatal rats.