Daily vertical distribution of zooplankton in two oligo-mesotrophic north Patagonian lakes (39° S, Chile) / Distribuição vertical diária do zooplâncton em dois lagos oligo-mesotróficos ao norte da Patagônia (39º S, Chile)

Abstract The zooplankton communities often exhibit daily vertical migrations to avoid natural ultraviolet radiation and/or fish predation. However there is no information on this topic in Chilean North Patagonian lakes up to date. Therefore, this study deals with a first characterization of plankton crustacean daily vertical migration in two temperate, oligotrophic lakes (Villarrica and Panguipulli lakes, 39°S) in Southern Chile. Zooplankton were collected at different depths intervals (0-10m, 10-20 m, 20-30m, 30-40m) at early morning, middle day, evening and night in the studied site. The results revealed that zooplankton species (Daphnia pulex, Ceriodaphnia dubia, Neobosmina chilensis, Mesocyclops araucanus, and Tropocyclops prasinus) are abundant in surface zones at night, early morning and evening, whereas at middle day the zooplankton abundances are high at deep zones. The results agree with observations for Argentinean and North American lakes where these daily migration patterns in crustacean zooplankton species were reported due mainly natural ultraviolet radiation exposure, whereas for northern hemisphere lakes the vertical migration is due to combined effect of natural ultraviolet radiation and fish predation exposure.

Resumo As comunidades zooplanctônicas frequentemente exibem migrações verticais diárias para evitar a radiação ultravioleta natural e/ou a predação de peixes. No entanto, não há informações sobre esse tema em lagos chilenos no norte da Patagônia até a presente data. Portanto, este estudo trata de uma primeira caracterização da migração vertical diária de crustáceo planctônico em dois lagos temperados e oligotróficos (lagos Villarrica e Panguipulli, 39º S) no sul do Chile. O zooplâncton foi coletado em diferentes profundidades (0-10 m, 10-20 m, 20-30 m e 30-40 m) no início da manhã, ao meio-dia, à tarde e à noite no local estudado. Os resultados revelaram que as espécies de zooplâncton (Daphnia pulex, Ceriodaphnia dubia, Neobosmina chilensis, Mesocyclops araucanus e Tropocyclops prasinus) são abundantes nas zonas de superfície à noite, de manhã cedo e à tarde, enquanto, ao meio-dia, as abundâncias do zooplâncton são altas nas zonas de profundidade. Os resultados expostos corroboram as observações para outros lagos argentinos e da América do Norte, onde foram reportados esses padrões de migração diária em espécies crustáceas de zooplâncton por causa, principalmente, da exposição à radiação ultravioleta natural, enquanto, para lagos do hemisfério norte, a migração vertical se dá em razão do efeito combinado da radiação ultravioleta natural e exposição à predação.

Daily vertical distribution of zooplankton in two oligo-mesotrophic north Patagonian lakes (39° S, Chile).

The zooplankton communities often exhibit daily vertical migrations to avoid natural ultraviolet radiation and/or fish predation. However there is no information on this topic in Chilean North Patagonian lakes up to date. Therefore, this study deals with a first characterization of plankton crustacean daily vertical migration in two temperate, oligotrophic lakes (Villarrica and Panguipulli lakes, 39°S) in Southern Chile. Zooplankton were collected at different depths intervals (0-10m, 10-20 m, 20-30m, 30-40m) at early morning, middle day, evening and night in the studied site. The results revealed that zooplankton species (Daphnia pulex, Ceriodaphnia dubia, Neobosmina chilensis, Mesocyclops araucanus, and Tropocyclops prasinus) are abundant in surface zones at night, early morning and evening, whereas at middle day the zooplankton abundances are high at deep zones. The results agree with observations for Argentinean and North American lakes where these daily migration patterns in crustacean zooplankton species were reported due mainly natural ultraviolet radiation exposure, whereas for northern hemisphere lakes the vertical migration is due to combined effect of natural ultraviolet radiation and fish predation exposure.

Estudio de frecuencia y asociación de los polimorfismos RS965513 y RS1867277 del gen FOXE1 con el carcinoma papilar de tiroides y su riesgo de recurrencia en población chilena / Frequency and association of the polymorphisms RS965513 and RS1867277 of the FOXE1 gene with papillary thyroid carcinoma and its risk of recurrence in Chilean population

Introducción: El gen FOXE1 (Forkhead box E1) codifica para un factor de transcripción involucrado en la morfogénesis tiroidea. El cáncer papilar de tiroides (CPT) se ha asociado con polimorfismos (SNP) de FOXE1 rs1867277 y rs965513 en población asiática y europea. Nuestro objetivo fue investigar la frecuencia y asociación de SNP rs1867277 y rs965513 con CPT y el riesgo de recurrencia de CPT en sujetos chilenos. Métodos: Se reclutaron sujetos con y sin CPT, se describieron sus características epidemiológicas y la forma de presentación clínica (AJCC VIII y MINSAL 2013). Se aisló ADN de leucocitos periféricos y evaluó ambos SNP mediante PCR-HRM y secuencia. Se compararon las frecuencias alélicas y genotípicas entre casos CPT y controles, y entre pacientes CPT de distintos riesgos de recurrencia. Se compararon frecuencia y se estimó el riesgo con test de Fisher y cálculo de odds-ratio (OR). Resultados: De los 184 sujetos, 156 (85%) eran mujeres, edad 39,3±12,3 años; 90 con CPT y 94 sin CPT 26 (28,9%) pacientes eran de riesgo muy bajo, 45 (50%) bajo, 16 (17,8%) intermedio y 3 (3,3%) alto según MINSAL 2013. En relación a la frecuencia de alelo menor (MAF) calculada en sujetos control y CPT, fue 31,7% y 24,5% (SNP rs965513), y 36,7% y 30,1% 8 (rs1867277), respectivamente (p NS). Tampoco fueron diferentes las MAF calculados y comparados entre pacientes con CPT de riesgo bajo e intermedio/alto. Sin embargo, la combinación de los genotipos rs1867277GG y rs965513AA se asoció a mayor riesgo de CPT. Conclusiones: En pacientes chilenos, se describe una frecuencia MAF de los SNP rs1867277 y rs965513 cercana a un 30%, las cuales no se asocian a CPT ni riesgo de recurrencia, sin embargo, sujetos con una combinación genotípica particular podrían tener mayor riesgo de CPT.

FOXE1 gene (Forkhead E1 box) codes for a transcription factor involved in thyroid morphogenesis. Papillary thyroid cancer (PTC) has been associated with FOXE1 polymorphisms (SNPs) rs1867277 and rs965513 in Asian and European population. Our aim was to investigate the frequency and the association of SNPs rs1867277 and rs965513 with PTC and the risk of recurrence of PTC in Chilean subjects. Methods: We recruited subjects with and without PTC. In those with PTC, their epidemiological characteristics and clinical features presentation are described according to AJCC VIII and MINSAL 2013 scales. Peripheral leukocyte DNA was isolated and both SNPs were evaluated using PCR-HRM and sequencing. Allelic and genotypic frequencies were compared between PTC cases and controls, and between PTC patients with different recurrence risks. Results: Of the 184 subjects, 156 (85%) were women, age 39.3 ± 12.3 years; 94 (51%) without PTC and 90 with PTC (49%): 26 (28.9%) patients had very low, 45 (50%) low, 16 (17.8%) intermediate and 3 (3.3%) high risk of recurence according to MINSAL 2013. Regarding the minor allele frequency (MAF) calculated on control and PTC subjects, was 31.7% and 24.5% (SNP rs965513), and 36.7% and 30.1% (rs1867277), respectively (p NS). In patients with PTC, MAFs were not different between patients with low and intermediate/high risk PTC. However, the combination of rs1867277GG and rs965513AA genotypes were associated with an increased risk of PTC. Conclusions: In Chilean patients, the MAF frequency of SNPs rs1867277 and rs965513 is near 30%, and they are are not associated with PTC or its risk of recurrence. However, subjects with a particular genotypic combination may have an increased risk of PTC.

Estudio e identificación de microRNA en exosomas urinarios en hipertensión arterial mineralocorticoide / Study and identification of microRNA in urinary exosomes in mineralocorticoid arterial hypertension

About 15% of the essential hypertensive patients would have a low activity of the 11ßHSD2 enzyme, which inactivates cortisol (F) to cortisone (E). Gene expression can be negatively regulated by miRNA. Urinary exosomes and their specific content (miRNA/proteins) represent a valuable tool as a biomarker for the diagnosis and prognosis of the disease. Aim: To evaluate the expression of miRNA specific for 11ßHSD2 in samples of urinary exosomes and to determine its association with biochemical variables associated with mineralocorticoid metabolism. Subjects and Methods: Cross-sectional study in subjects between 10-60 years. They were classified into subjects with high F/E (> p75) and low cortisone (< p25) and control subjects. The urinary exosomes were isolated with the Invitrogen kit. Bioinformatic analysis was performed with Mir Walk to identify specific miRNAs of HSD11B2. The expression of miRNA was evaluated by qRT PCR. The comparisons were made with the Mann-Whitney test. Results: 7.1% of the subjects are suggestive of a partial deficiency of 11ßHSD2 (NC-AME). The expression of miR-488 was higher in NC-AME than in controls (5839 ± 1719 vs 3,437 ± 2,581; p = 0.01). We found positive associations between mir-615 and ARP; miR-488 and the sodium/potassium ratio; miR-1205 with age and urinary sodium excretion; miR-494 with age, activity MMP9 and NGAL. Conclusion: We identified high expression of miR488 in NC-AME subjects and associations of miRNAs with biochemical variables associated with mineralocorticoid metabolism. Thus, exosomes and their miRNA content could be potential regulators and biomarkers of 11ßHSD2 activity.

The influence of magnetic order on the magnetoresistance anisotropy of Fe1 + δ-x Cu x Te.

We performed resistance measurements on [Formula: see text]Cu x Te with [Formula: see text] in the presence of in-plane applied magnetic fields, revealing a resistance anisotropy that can be induced at a temperature far below the structural and magnetic zero-field transition temperatures. The observed resistance anisotropy strongly depends on the field orientation with respect to the crystallographic axes, as well as on the field-cooling history. Our results imply a correlation between the observed features and the low-temperature magnetic order. Hysteresis in the angle-dependence indicates a strong pinning of the magnetic order within a temperature range that varies with the Cu content. The resistance anisotropy vanishes at different temperatures depending on whether an external magnetic field or a remnant field is present: the closing temperature is higher in the presence of an external field. For [Formula: see text] the resistance anisotropy closes above the structural transition, at the same temperature at which the zero-field short-range magnetic order disappears and the sample becomes paramagnetic. Thus we suggest that under an external magnetic field the resistance anisotropy mirrors the magnetic order parameter. We discuss similarities to nematic order observed in other iron pnictide materials.

Daily vertical distribution of zooplankton in two oligo-mesotrophic north Patagonian lakes (39° S, Chile)

Abstract The zooplankton communities often exhibit daily vertical migrations to avoid natural ultraviolet radiation and/or fish predation. However there is no information on this topic in Chilean North Patagonian lakes up to date. Therefore, this study deals with a first characterization of plankton crustacean daily vertical migration in two temperate, oligotrophic lakes (Villarrica and Panguipulli lakes, 39°S) in Southern Chile. Zooplankton were collected at different depths intervals (0-10m, 10-20 m, 20-30m, 30-40m) at early morning, middle day, evening and night in the studied site. The results revealed that zooplankton species (Daphnia pulex, Ceriodaphnia dubia, Neobosmina chilensis, Mesocyclops araucanus, and Tropocyclops prasinus) are abundant in surface zones at night, early morning and evening, whereas at middle day the zooplankton abundances are high at deep zones. The results agree with observations for Argentinean and North American lakes where these daily migration patterns in crustacean zooplankton species were reported due mainly natural ultraviolet radiation exposure, whereas for northern hemisphere lakes the vertical migration is due to combined effect of natural ultraviolet radiation and fish predation exposure.

Resumo As comunidades zooplanctônicas frequentemente exibem migrações verticais diárias para evitar a radiação ultravioleta natural e/ou a predação de peixes. No entanto, não há informações sobre esse tema em lagos chilenos no norte da Patagônia até a presente data. Portanto, este estudo trata de uma primeira caracterização da migração vertical diária de crustáceo planctônico em dois lagos temperados e oligotróficos (lagos Villarrica e Panguipulli, 39º S) no sul do Chile. O zooplâncton foi coletado em diferentes profundidades (0-10 m, 10-20 m, 20-30 m e 30-40 m) no início da manhã, ao meio-dia, à tarde e à noite no local estudado. Os resultados revelaram que as espécies de zooplâncton (Daphnia pulex, Ceriodaphnia dubia, Neobosmina chilensis, Mesocyclops araucanus e Tropocyclops prasinus) são abundantes nas zonas de superfície à noite, de manhã cedo e à tarde, enquanto, ao meio-dia, as abundâncias do zooplâncton são altas nas zonas de profundidade. Os resultados expostos corroboram as observações para outros lagos argentinos e da América do Norte, onde foram reportados esses padrões de migração diária em espécies crustáceas de zooplâncton por causa, principalmente, da exposição à radiação ultravioleta natural, enquanto, para lagos do hemisfério norte, a migração vertical se dá em razão do efeito combinado da radiação ultravioleta natural e exposição à predação.

The Latin American Biological Dosimetry Network (LBDNet).

Biological Dosimetry is a necessary support for national radiation protection programmes and emergency response schemes. The Latin American Biological Dosimetry Network (LBDNet) was formally founded in 2007 to provide early biological dosimetry assistance in case of radiation emergencies in the Latin American Region. Here are presented the main topics considered in the foundational document of the network, which comprise: mission, partners, concept of operation, including the mechanism to request support for biological dosimetry assistance in the region, and the network capabilities. The process for network activation and the role of the coordinating laboratory during biological dosimetry emergency response is also presented. This information is preceded by historical remarks on biological dosimetry cooperation in Latin America. A summary of the main experimental and practical results already obtained by the LBDNet is also included.

The effects of post-growth annealing on the structural and magnetic properties of BaFe2As2.

We investigate the effects of post-growth annealing on the structural and magnetic properties of BaFe2As2. Magnetic susceptibility measurements, which exhibit a signal corresponding to the magnetic phase transition, and high-resolution x-ray diffraction measurements, which directly probe the structural order parameter, show that annealing causes the ordering temperatures of both the phase transitions to increase, sharpen and converge. In the as grown sample, our measurements show two distinct transitions corresponding to structural and magnetic ordering, which are separated in temperature by approximately 1 K. After 46 days (d) of annealing at 700 °C, the two become concurrent in temperature. These measurements demonstrate that the structural phase transition is second-order like when the magnetic and structural phase transitions are separated in temperature, and first-order like when the two phase transition temperatures coincide. This observation indicates that annealing causes the system to cross a hitherto undiscovered tricritical point. In addition, x-ray diffraction measurements show that the c-axis lattice parameter increases with annealing up to 30 d, but remains constant for longer annealing times. Comparisons of BaFe2As2 to SrFe2As2 are made when possible.

Factor neurotrófico derivado del cerebro como marcador de conducta suicida en pacientes con trastorno depresivo mayor / Brain-derived neurotrophic factor as a marker of suicidal behavior in major depressive disorder patients

Suicidal behavior, understood as a continuum from ideation to completed suicide, through the suicide attempt, is a major health concern worldwide in both adult and adolescent population. Major depressive disorder is consistently the most prevalent disorder among individuals who commit suicide and one of the leading causes of disability worldwide. The Brain-derived neurotrophic factor (BDNF) appears to be a molecular substrate of stress, because its expression is reduced in these condition which would be a major risk factor for depression. Furthermore, antidepressant treatment has effects on BDNF levels opposite to those of stress or depression. Postmortem studies have shown that mRNA expression and protein levels of BDNF tended to be significantly reduced in the brains of people who have committed suicide independent of psychiatric disorders, mainly in the prefrontal cortex and hippocampus. Moreover clinical studies have shown a lower presence of serum BDNF in depressed patients who have attempted suicide compared with healthy controls. In order to separate the possible contamination that may exist between depression and suicidal behavior, this article reviews the existing evidence on the levels and the expression of BDNF in depressed populations with and without suicide attempts.

La conducta suicida, comprendida como un continuo que va desde la ideación hasta el suicidio consumado, pasando por el intento de suicidio, es un problema de salud importante en todo el mundo, tanto en población adulta como adolescente. El trastorno depresivo mayor es consistentemente el trastorno más frecuente entre las personas que se suicidan y una de las principales causas de discapacidad en todo el mundo. El factor neurotrófico derivado del cerebro (BDNF) parece ser un sustrato molecular de estrés, ya que su expresión se reduce en esta condición y sería un factor de riesgo importante para la depresión. Además, el tratamiento antidepresivo tiene efectos sobre los niveles de BDNF opuestas a los del estrés o la depresión. Estudios de autopsias han demostrado que la expresión de mRNA y los niveles de proteína BDNF tendieron a reducirse significativamente en los cerebros de las personas que se han suicidado independiente de los trastornos psiquiátricos, principalmente en la corteza prefrontal y el hipocampo. Por otra parte, los estudios clínicos han demostrado una menor presencia de BDNF sérico en los pacientes deprimidos que han intentado suicidarse en comparación con los controles sanos. Con el fin de separar la posible contaminación que pueda existir entre la depresión y el comportamiento suicida, este artículo revisa la evidencia existente sobre los niveles y la expresión de BDNF en poblaciones con trastorno depresivo mayor con y sin intentos de suicidio.

Validación de la entrevista diagnóstica estructurada DISC-IV para la identificación de trastornos psiquiátricos en niños y adolescentes en Chile / Validation of the DISC-IV structured diagnostic interview to identify psychiatric disorders in children and adolescents in Chile

Introduction: In Chile there are scarce validated instruments in order to perform categorical psychiatric diagnosis both in children and adolescents. DISC-IV Spanish version validation indexes are presented. Method: A convenience sample was collected from outpatient psychiatric services as well as from private medical facilities and drug-dependence outpatient centres from Concepción, Chile. Subjects of both genders between 7 and 18 years of age, with a psychiatric diagnosis were included in the study (affective disorder, anxiety, drugs abuse and dependence, and behaviour disorder). In addition 18 subjects without psychiatric disorder were selected from a secondary school. Each selected subject that agreed to participate in the study was interviewed by a clinical experienced child psychiatrist, diagnose-blinded, using DSM-IV check list, in order to decide if the subject fulfilled DSM-IV criteria. Later, to patients 12 years old or older, or to their caregiver for children younger than 12 years DISC-IV was applied by some of the previously trained lay interviewers. Quality controls of the interviews were carried out. Data were entered to SPSS file to obtain DISC-IV validation indexes. Results: 144 subjects were incorporated in the study. Cohen's Kappa indexes, a statistical measure of inter-rater agreement, varied between 0.53 for anxiety disorders, and 0.88 for substance abuse and dependence. Every group presented high specificity ranging between 0.55 and 0.83. Interviews answered by adolescents were less sensitive for TDA (0.23) and anxiety (0.40), whereas in parents, sensitivity decreases for affective disorders (0.50). Conclusion: DISC-IV is a valid instrument to be used in the research about children and adolescent mental health...

Introducción: En Chile existen escasos instrumentos validados para efectuar diagnósticos psiquiátricos categoriales en población infantil y adolescente. Se presentan los índices de validación obtenidos para la versión en español del DISC-IV. Método: Una muestra por conveniencia fue seleccionada de los registros clínicos de los servicios de psiquiatría ambulatorios de Concepción, consultas privadas y centros de atención a drogodependientes. Ésta incluyó a sujetos de ambos sexos, con edades entre 7 y 18 años, que presentaran algún diagnóstico incluido en el estudio (trastornos del ánimo, ansiosos, abuso y dependencia a sustancias y trastornos del comportamiento). Además se seleccionaron de un establecimiento educacional a 18 sujetos sin diagnóstico psiquiátrico. Cada sujeto seleccionado que aceptó participar del estudio, y el cuidador responsable, fueron entrevistados por un psiquiatra infantil entrenado, ciego al diagnóstico inicial, utilizando un check-list basado en los criterios DSM-IV, para obtener diagnósticos categoriales. Posteriormente, entrevistadores legos previamente capacitados, aplicaron al paciente, si tenía 12 años o más, o a su cuidador principal, para los menores de 12 años, la entrevista estructurada DISC-IV. Se realizaron controles de calidad de las entrevistas. Los datos fueron ingresados a un archivo SPSS para ser procesados y obtener índices de validación del DISC-IV. Resultados: Ciento cuarenta y cuatro sujetos ingresaron al estudio. Los Índice Kappa de Cohen, que miden el acuerdo inter-evaluadores, varían entre ,53, para los trastornos ansiosos, y ,88, para abuso y dependencia. En todos los grupos la especificidad es alta (> 0,9) y la sensibilidad varía entre ,55y ,83. Las entrevistas respondidas por adolescentes son menos sensibles para TDA (0,23) y ansiedad (0,40), mientras en los padres la sensibilidad disminuye para los cuadros afectivos (0,50)...

Estrés postraumático en población infantojuvenil post 27F / Post-traumatic stress disorder in young population after the natural disaster on February 27, 2010

Introduction: the post-traumatic stress disorder (PTSD) is one of the most frequent consequences of exposure to natural disasters, disabling both children and adults. Objectives: to describe prevalence of probable PTSD in children who experienced the disaster that occurred in southern Chile in february 2010. Methodology: the sample consisted of 1,300 participants aged 9-16 from the Bío Bío region. The study took place six months after the event occurred. The Child PTSD Symptom Scale (CPSS) and a questionnaire to assess socio-demographic aspects and potential PTSD predictors were used. Results: The overall rate of probable PTSD was 30.4 percent in the young population of females and 15.0 percent in males. The most strongly linked factors to the presence of PTSD were deteriorating family relationships after the event and intense fear and life threatening experiences during the event. Conclusions: results show the need for implementing preventive programs on young population affected by disasters that also include the response of the families involved.

Introducción: el trastorno de estrés postraumático (TEPT) es una de las consecuencias de la exposición a desastres naturales más frecuente y discapacitante tanto en niños y niñas como en adultos. Objetivos: se describe la prevalencia de probable TEPT en niños, niñas y adolescentes que vivieron el desastre natural de febrero de 2010 en el sur de Chile. Metodología: se estudió una muestra de 1.300 participantes de 9 a 16 años de la región del Bío Bío. La aplicación se realizó a seis meses de ocurrido el evento. Se empleó la Escala Infantil de Síntomas de Trastorno de Estrés Postraumático CPSS y un cuestionario de aspectos sociodemográficos y de potenciales factores predictores de estrés postraumático. Resultados: la tasa total probable de TEPT fue de 30,4 por ciento en la población infantojuvenil de sexo femenino y de 15,0 por ciento en la de sexo masculino. Los factores que aparecieron más fuertemente vinculados a la presencia de TEPT fueron el empeoramiento de las relaciones familiares posterior al evento y la experiencia de miedo intenso y de riesgo vital durante el evento. Conclusiones: los resultados indican la importancia de implementar programas preventivos en población infantojuvenil afectada por desastres que consideren también la respuesta de las familias.

Interlaboratory comparison of dicentric chromosome assay using electronically transmitted images.

The bottleneck in data acquisition during biological dosimetry based on a dicentric assay is the need to score dicentrics in a large number of lymphocytes. One way to increase the capacity of a given laboratory is to use the ability of skilled operators from other laboratories. This can be done using image analysis systems and distributing images all around the world. Two exercises were conducted to test the efficiency of such an approach involving 10 laboratories. During the first exercise (E1), the participant laboratories analysed the same images derived from cells exposed to 0.5 and 3 Gy; 100 images were sent to all participants for both doses. Whatever the dose, only about half of the cells were complete with well-spread metaphases suitable for analysis. A coefficient of variation (CV) on the standard deviation of ∼15 % was obtained for both doses. The trueness was better for 3 Gy (0.6 %) than for 0.5 Gy (37.8 %). The number of estimated doses classified as satisfactory according to the z-score was 3 at 0.5 Gy and 8 at 3 Gy for 10 dose estimations. In the second exercise, an emergency situation was tested, each laboratory was required to score a different set of 50 images in 2 d extracted from 500 downloaded images derived from cells exposed to 0.5 Gy. Then the remaining 450 images had to be scored within a week. Using 50 different images, the CV on the estimated doses (79.2 %) was not as good as in E1, probably associated to a lower number of cells analysed (50 vs. 100) or from the fact that laboratories analysed a different set of images. The trueness for the dose was better after scoring 500 cells (22.5 %) than after 50 cells (26.8 %). For the 10 dose estimations, the number of doses classified as satisfactory according to the z-score was 9, for both 50 and 500 cells. Overall, the results obtained support the feasibility of networking using electronically transmitted images. However, before its implementation some issues should be elucidated, such as the number and resolution of the images to be sent, and the harmonisation of the scoring criteria. Additionally, a global website able to be used for the different regional networks, like Share Points, will be desirable to facilitate worldwide communication.

Smectic-A and smectic-C phases and phase transitions in 8S5 liquid-crystal-aerosil gels.

High-resolution x-ray scattering studies of the nonpolar thermotropic liquid crystal 4-n-pentylphenylthiol-4'-n-octyloxybenzoate (8S5) in aerosil gel nanonetworks reveal that the aerosil-induced disorder significantly alters both the nematic to smectic-A and smectic-A to smectic-C phase transitions. The limiting 8S5 smectic-A correlation length follows a power-law dependence on the aerosil density in quantitative agreement with the limiting lengths measured previously in other smectic-A liquid crystal gels. The smectic-A to smectic-C liquid crystalline phase transition is altered fundamentally by the presence of the aerosil gel. The onset of the smectic-C phase remains relatively sharp but there is an extended coexistence region where smectic-A and smectic-C domains can exist.

Biological dosimetry intercomparison exercise: an evaluation of triage and routine mode results by robust methods.

Well-defined protocols and quality management standards are indispensable for biological dosimetry laboratories. Participation in periodic proficiency testing by interlaboratory comparisons is also required. This harmonization is essential if a cooperative network is used to respond to a mass casualty event. Here we present an international intercomparison based on dicentric chromosome analysis for dose assessment performed in the framework of the IAEA Regional Latin American RLA/9/054 Project. The exercise involved 14 laboratories, 8 from Latin America and 6 from Europe. The performance of each laboratory and the reproducibility of the exercise were evaluated using robust methods described in ISO standards. The study was based on the analysis of slides from samples irradiated with 0.75 (DI) and 2.5 Gy (DII). Laboratories were required to score the frequency of dicentrics and convert them to estimated doses, using their own dose-effect curves, after the analysis of 50 or 100 cells (triage mode) and after conventional scoring of 500 cells or 100 dicentrics. In the conntional scoring, at both doses, all reported frequencies were considered as satisfactory, and two reported doses were considered as questionable. The analysis of the data dispersion among the dicentric frequencies and among doses indicated a better reproducibility for estimated doses (15.6% for DI and 8.8% for DII) than for frequencies (24.4% for DI and 11.4% for DII), expressed by the coefficient of variation. In the two triage modes, although robust analysis classified some reported frequencies or doses as unsatisfactory or questionable, all estimated doses were in agreement with the accepted error of ±0.5 Gy. However, at the DI dose and for 50 scored cells, 5 out of the 14 reported confidence intervals that included zero dose and could be interpreted as false negatives. This improved with 100 cells, where only one confidence interval included zero dose. At the DII dose, all estimations fell within ±0.5 Gy of the reference dose interval. The results obtained in this triage exercise indicated that it is better to report doses than frequencies. Overall, in both triage and conventional scoring modes, the laboratory performances were satisfactory for mutual cooperation purposes. These data reinforce the view that collaborative networking in the case of a mass casualty event can be successful.

Estrés postraumático en niños y adolescentes abusados sexualmente / Post-traumatic stress disorder among sexually abused children and adolescents

Introduction: The development of Post-Traumatic Stress Disorder (PTSD) is a frequently observed effect of sexual abuse among children and adolescents. Objectives: This study focused on the prevalence of PTSD among children and adolescents who were victims of sexual abuse. Method: A sample of 75 sexually abused children and adolescentes seeking outpatient care were evaluated utilizing a Children's Post Traumatic Stress Scale (CPSS). Results: 21.3 percent met the criteria for PTSD, an additional 16 percent met the criteria for a SubSyn-drome. Conclusíons: These data confirm the importance of focusing on post-traumatic symptomatology on sexually abused children and adolescents. Equally important is the finding that the majority of the children in the sample did not show symptomatology at the time of the study.

Introducción: El desarrollo de sintomatología postraumática es uno de los efectos del abuso sexual de niños y adolescentes que se observa con mayor frecuencia. Objetivos: En el presente estudio se evaluó la prevalencia de trastorno de estrés postraumático y del denominado subsíndrome de estrés postraumático en niños y adolescentes víctimas de abusos sexuales. Método: La muestra estuvo constituida por 75 niños y adolescentes sexualmente abusados consultantes de centros de atención quienes fueron evaluados con la Escala Infantil de Síntomas del Trastorno de Estrés Postraumático (CPSS). Resultados: Un 21,3 por ciento cumplió con los criterios para el diagnóstico de Trastorno de Estrés Postraumático, y un 16 por ciento adicional cumplió con los criterios de subsíndrome de Estrés Postraumático. Conclusiones: Estos datos confirman la importancia de considerar la sintomatología postraumática como un foco de evaluación y tratamiento en niños y adolescentes sexualmente abusados. Sin embargo, es de importancia destacar que la mayoría de los niños y adolescentes evaluados no informó presentar sintomatología postraumática acusada al momento del estudio.

Prevalencia de trastornos depresivos e impedimento asociado en adolescentes de sexo femenino / Depressive disorders prevalence and associated impediments in female adolescents

Background: From early adolescence, depressive disorders experience a significant increase, especially in female population, showing not only immediate adverse consequences, but also at later stages in adult development. Although its importance, there are few studies regarding the prevalence of these disorders in Chilean adolescents. Methods: Estimation of prevalence of major depression and dysthymic disorders in 172 students from first year of secondary education. The computerized interview DISC-IV obtained a diagnosis based on DSM-IV criteria. Results: 10 percent of the population showed a depressive episode in the last year and more than 5 percent in the last month. The incidence of dysthymic disorder was low (1.2 percent). The incidence of major depressive sub threshold in the last year was 11.6 percent and 8.5 percent for sub threshold dysthymic disorder. Conclusions: Most of female with depressive disorders and sub threshold disorders presented impediments related to symptoms experienced. Although these high rates might suggest problems in the conceptualization of depressive disorders, they constitute the result of strict DSM-IV criteria application, including clinical significant criteria. These results are indicative of the need to pay attention to emotional wellbeing of female adolescents.

Introducción: Los trastornos depresivos se incrementan de modo notorio a partir del inicio de la adolescencia, especialmente en las mujeres, con efectos adversos tanto inmediatos como en el desarrollo posterior. Pese a su importancia, en Chile existen pocos estudios de la prevalencia de estos trastornos en adolescentes. Método: Se estimó la prevalencia de último mes y de último año de depresión mayor y de distimia, en una muestra de 172 estudiantes mujeres de primero medio de liceos de Concepción. Se utilizó la entrevista digitalizada DISC-IV que permite obtener diagnóstico según criterios DSM-IV. Resultados: Casi un 10 por ciento de las niñas presentaron un episodio depresivo mayor en el último año y poco más de un 5,0 por ciento en el último mes; la prevalencia de trastorno distímico fue muy baja, 1,2 por ciento. La prevalencia de último año de episodio depresivo mayor subumbral fue de 11,6 por ciento y la de distimia de 8,5 por ciento. En la mayoría de las niñas con trastornos depresivos y con trastornos subumbrales se observó presencia de malestar o impedimento asociado a los síntomas experimentados. Conclusiones: Si bien estas tasas tan elevadas pueden estar sugiriendo dificultades en la conceptualización de los trastornos depresivos, son el resultado de la aplicación estricta de los criterios DSM-IV, incluyendo el criterio de significación clínica, e indican la necesidad de poner atención en el bienestar emocional de las adolescentes.

Sintomatología depresiva y ansiosa en estudiantes de enseñanza media / Depressive and anxiety disorders in high school students

Introducción: Los síntomas y trastornos depresivos y ansiosos en adolescentes son un problema de salud relevante, con implicaciones tanto inmediatas como en el desarrollo posterior de los jóvenes. Objetivo: Estimar la prevalencia de síntomas y síndromes depresivos y ansiosos en una muestra representativa de adolescentes. Muestra y Método: Se evaluó una muestra de 700 adolescentes de la comuna de Concepción, representativos de los cuatros niveles de la enseñanza media, utilizando la versión actualizada del Inventario de Depresión de Beck (BDI-II) y el Inventario de Ansiedad de Beck (BAI). Resultados: Se obtuvo una cifra de prevalencia de síndrome depresivo de 32,6 por ciento y de síndrome ansioso de 42,3 por ciento. Conclusiones: Las tasas obtenidas son concordantes con otros estudios realizados en Chile, y claramente más altas que las encontradas en estudios realizados en muestras semejantes en otros países. Es necesario entender mejor las causas e implicaciones de estos altos niveles de malestar emocional en nuestros adolescentes. Desde un punto de vista más aplicado, es clara la importancia de fortalecer estrategias destinadas a mejorar el nivel de bienestar emocional de éstos.

Diferencias de género en psicopatología en la niñez: hipótesis explicativas / Gender differences in infancy psychopathology: explanatory hypothesis

Introducción: Diversos trastornos psicopatológicos son más predominantes en niños que en niñas, sin que existan explicaciones con suficiente respaldo de este fenómeno. Objetivo: Presentar una síntesis actualizada de las principales hipótesis explicativas de las diferencias de género en psicopatología en la niñez. Método: Se revisaron en forma manual y a través de las bases de datos Medline y Proquest las publicaciones entre 1990 y 2003, centradas en diferencias de género en psicopatología, utilizando las siguientes palabras claves: diferencias de género (o de sexo) y psicopatología. Resultados: Se encontraron 85 artículos. Se mencionan los trastornos más frecuentes en niños y en niñas y las edades en que se presentan. Se describen las hipótesis explicativas de mayor importancia (artifactual, biológicas, ambientales) y las relacionadas al desarrollo emocional, social y cognitivo. Conclusiones: Dado que gran parte de los trastornos donde los niños predominan corresponden a trastornos de origen temprano y persistentes, es posible que tengan relación con déficits neuroevolutivos. Persisten interrogantes fundamentales en este tema, especialmente la causa de estos déficits neuroevolutivos y su interrelación con factores ambientales, y la aparente discontinuidad de la psicopatología en la mujer entre la niñez y adolescencia.

Plasmapheresis for the prophylaxis and treatment of recurrent focal segmental glomerulosclerosis following renal transplant.

We evaluated 10 patients with primary focal segmental glomerulosclerosis (FSGS) treated with plasmapheresis (PS) following renal transplantation. Three patients lost their first graft due to FSGS recurrence. In seven patients, PS was indicated as treatment for probable recurrence defined as the onset of proteinuria above 1 g/24 hours. In the remaining three patients, treatment was started in the first week posttransplant as prophylaxis against recurrence. The PS protocol was 17 sessions with the exchange of 2.5 L of plasma for 5% albumin over 10 to 12 weeks. Losartan (25 to 100 mg/d) was given to most patients at the end of PS treatment. The mean follow-up time after PS was 10 months. All patients currently have a functioning graft. A full response to treatment, defined as persistently reduced proteinuria to less than 500 mg/24 hours or the lack of recurrence in prophylactic treatment, was achieved in six patients. Three patients showed a partial decrease in proteinuria (to less than 1 g/24 hours). One patient failed to respond and still has nephrotic range proteinuria. No adverse effects of PS were recorded. A prompt start of PS combined with the use of losartan yields good results in the prophylaxis and treatment of recurrent FSGS following renal transplant in terms of quickly reduced proteinuria. Given the natural course of FSGS, a longer follow-up is needed to estimate the impact of PS on graft survival.