Radioquimioterapia neoadyuvante en cáncer de recto: Relevancia clínica del downstaging y la respuesta patológica completa

Antecedentes: La radioquimioterapia neoadyuvante es uno de los pilares del tratamiento del cáncer de recto localmente avanzado. La neoadyuvancia ha demostrado disminuir la recidiva local, generando también un downstaging tumoral, llegando incluso a una respuesta patológica completa (RPC), esta última relacionada con una mejor sobrevida global (SG) y sobrevida libre de enfermedad (SLE). Objetivo: Reportar los resultados anátomo-patológicos del tratamiento con radioquimioterapia en cáncer de recto, analizando su relación con la SG y la SLE. Material y Método: Estudio de cohorte prospectivo. Se analiza base de datos de cirugías coloproctológicas del Hospital Clínico de la Universidad de Chile, entre los años 20042019, incluyendo pacientes con cáncer de recto medio y bajo localmente avanzados, los cuales recibieron neoadyuvancia y posteriormente cirugía. Se realizó el análisis de sobrevida con el método de Kaplan-Meier y el test Log-rank para su comparación. Se consideró estadísticamente significativo un valor de p < 0,05. Resultados: 411 pacientes fueron operados por cáncer de recto, 143 pacientes recibieron neoadyuvancia, el 19% registró RPC. La SG del grupo con RPC fue 94% (IC 95%; 59,79-79,41%) mientras que la del grupo sin RPC fue 71% (IC 95%; 66,64-99,20%) (p = 0,018), la SLE en aquellos pacientes con RPC alcanzó un 100%, mientras que en aquellos sin RPC fue 74% (IC 95%; 64,08-81,28) (p = 0,008). Conclusiones: Los pacientes con RPC mostraron mejores resultados a largo plazo que aquellos sin RPC. La RPC podría indicar un perfil tumoral biológico favorable, con menos tendencia a la recurrencia y mejor supervivencia.

Background: One of the mainstays in the treatment of locally advanced rectal cancer is neoadjuvant chemoradiotherapy. Neoadjuvant therapy have demonstrated to decrease local recurrence, also generating tumor downstaging, even leading to a pathological complete response (PCR), the latter related to better overall survival (OS) and disease-free survival (SLE). Aim: To report the anatomo-pathological results of treatment with chemoradiotherapy in rectal cancer, analyzing the relationship with OS and SLE. Material and Method: Prospective cohort study. A database of colorectal surgeries from the Clinical Hospital of the University of Chile between the years 2004-2019, including patients with locally advanced low and middle rectal cancer, who received neoadjuvant and later surgery. Survival analysis was made with the Kaplan-Meier method and the Log-rank test for comparison. A value of p < 0.05 was considered statistically significant. Results: 411 patients underwent surgery for rectal cancer, 143 patients received neoadjuvant therapy, 19% registered PCR. The OS of the group with PCR was 94% (95% CI; 59.79-79.41%) while that of the group without PCR was 71% (95% CI; 66.64-99.20%) (p = 0.018), the SLE in those patients with PCR reached 100%, while in those without PCR it was 74% (95% CI; 64.08-81.28) (p = 0.008). Conclusions: Patients with PCR have better long-term results than those without PCR. PCR could indicate a favorable biological tumor profile, with less tendency to recurrence and improved survival.

Enfermedad de Castleman unicéntrica, una causa infrecuente de masa cervical / Unicentric Castleman disease, an infrequent cause of cervical mass

La enfermedad de Castleman (EC) describe una serie de desórdenes linfoproliferativos de patrones histológicos similares, pero de etiologías, presentaciones clínicas y enfrentamientos notoriamente variables. Se presenta el caso de un paciente que consultó por masa cervical, cuyo estudio final concluyó EC unicéntrica, la cual se resolvió de forma quirúrgica. Además, se presenta una revisión actualizada del tema, con foco en la enfermedad unicéntrica.

Castleman's disease (CD) describes several lymphoproliferative disorders with similar histological patterns, but with notoriously variable etiologies, clinical presentations, and management. We present the case of a patient who consulted with cervical mass, whose final study concluded with unicentric CD, which was treated surgically. In addition, an updated review of the subject is presented, focusing on unicentric disease.

COVID-19 pandemic on coronary artery and cerebrovascular diseases in Southern Spain: interrupted time series analysis.

OBJECTIVE: Healthcare systems have been put under intense pressure by the COVID-19 pandemic, although some studies have shown a decline in hospital admissions for cardiovascular and cerebrovascular diseases during the first and second wave of the pandemic. In addition, studies analyzing gender and procedural differences are scarce. The present study aimed to determine the impact of the pandemic on hospital admissions for acute myocardial infarction (AMI) and cerebrovascular disease (CVD) in Andalusia (Spain) and analyzed differences by gender and by percutaneous coronary interventions performed. PATIENTS AND METHODS: An interrupted time series analysis of AMI and CVD hospital admissions in Andalusia (Spain) was carried out to measure the impact of the COVID-19 outbreak. AMI and CVD cases admitted daily in public hospitals of Andalusia between January 2018 and December 2020 were included. RESULTS: During the pandemic, significant reductions in AMI [-19%; 95% confidence interval (CI): (-29%, -9%), p<0.001] and CVD [-17%; 95% CI: (-26%, -9%); p<0.01] in daily hospital admissions were observed. Differences were also produced according to the diagnosis (ST-Elevation Myocardial Infarction, Non-ST-Elevation Myocardial Infarction, other AMI and stroke), with a greater reduction in females for AMI and in males for CVD. Although there were more percutaneous coronary interventions during the pandemic, no significant reductions were observed. CONCLUSIONS: A decline in AMI and CVD daily hospital admissions during the first and second wave of COVID-19 pandemic was noted. Gender differences were observed, but no clear impact was observed in percutaneous interventions.

Biomateriales y tecnologías de impresión 3D en entrenamiento quirúrgico en otorrinolaringología: una revisión / Biomaterials and technologies of 3D printing in surgical training on otorhinolaryngology: a revision

La tecnología de fabricación aditiva o impresión 3D se ha posicionado como una herramienta transversal y de uso creciente en el mundo productivo y científico que ha otorgado la posibilidad de diseñar y crear elementos y modelos de diversa complejidad. En el área biomédica ha presentado un aumento significativo de sus aplicaciones a través del tiempo, actualmente teniendo relevancia en ámbitos como el planeamiento quirúrgico, la creación de prótesis, modelos anatómicos para educación y entrenamiento quirúrgico. Actualmente existen diversas dificultades que limitan la formación quirúrgica, especialmente en ciertas áreas de la otorrinolaringología como la cirugía de oído. El objetivo de la presente revisión narrativa fue actualizar los usos de la tecnología de impresión 3D para la creación de modelos para entrenamiento quirúrgico en otorrinolaringología, destacando sus potenciales usos en otología, rinología, cirugía de base de cráneo y vía aérea.

Additive manufacturing technology or 3D printing has positioned itself as a cross-cutting tool of increasing use in the productive and scientific world that has given the possibility of designing and creating different elements and models of varying complexity. In the biomedical area, it has presented a significant increase in its applications over time, currently having relevance in areas such as surgical planning, the creation of prostheses, anatomical models for education and surgical training. Currently there are various difficulties that limit surgical training, especially in certain areas of otorhinolaryngology such as ear surgery. The objective of this narrative review was to update the uses of 3D printing technology for the creation of models for surgical training in otorhinolaryngology, highlighting its potential uses in otology, rhinology, skull base and airway surgery.

Un cuerpo extraño inusual de cianoacrilato en el oído. Presentación de un caso clínico y revisión de la literatura / An unusual cyanoacrylate foreign body in the ear. Presentation of a clinical case and literature review

El pegamento basado en cianoacrilato posee una gran capacidad de adherencia a los tejidos, representando un problema cuando se encuentra en el oído externo debido a sus características anatómicas particulares. Se presenta un caso clínico de cuerpo extraño de cianoacrilato que ocluye el conducto auditivo externo y el tímpano, alterando la audición. Se describen los hallazgos y los intentos de extracción utilizando las alternativas terapéuticas descritas en la literatura, sin obtener resultados positivos, debiendo recurrir a la extracción quirúrgica. Además, se presentan detalles del procedimiento y los resultados. El paciente recupera la audición y la normalidad anatómica.

Cyanoacrylate-based glue has a great capacity for adhering to tissue, which is a problem when it is placed in the ear canal due to the anatomy of this structure. A clinical case of a cyanoacrylate foreign body occluding the external auditory canal and the tympanic membrane is presented. The therapeutics alternatives described in the literature used in the case failed, so, it was surgically removed by drilling the glue. Details of the procedure and results are presented. The patient recovers the hearing and anatomical normality.

Trastornos del gusto: actualización y aproximación clínica / Taste disorders: update and clinical approach

Resumen Los trastornos del gusto constituyen un grupo de alteraciones relativamente frecuentes en la práctica clínica. Son de etiología diversa, pudiendo afectar la vía gustativa en distintos niveles, manifestándose, clínicamente, con alteraciones cuantitativas y/o cualitativas de la sensibilidad gustativa. En gran parte de los casos se puede lograr un diagnóstico etiológico con una anamnesis adecuada, examen físico y exploraciones complementarias básicas. No obstante, existe poco entendimiento de su patogénesis, así como limitadas opciones terapéuticas, lo que implica la falta de algoritmos de diagnóstico y tratamiento completamente validados. El objetivo de la presente revisión es otorgar una actualización y un abordaje práctico de los trastornos del gusto.

Abstract Taste disorders represent a group of alterations relatively frequent in clinical practice. They have a diverse etiology, and they can affect the gustatory pathway at different levels, clinically manifesting with quantitative/qualitative alterations on taste sensitivity. In most of cases it is possibly to achieve an etiologically diagnosis with appropriate anamnesis, physical exploration, and basic complementary tests. However, their pathogenesis is not well understood, and they have limited therapeutic options, which determines a lack of well-validated diagnosis and treatment algorithms. The objective of this review is to provide and update and a practical approach to taste disorders.

Valores referenciales de posturografía basada en Nintendo Wii en población chilena

Resumen Introducción: La posturografía es un método de exploración complementario para valorar el grado de desplazamiento del centro de gravedad (COP); no debe usarse de forma aislada al evaluar equilibrio, pero se acepta para seguimiento de la respuesta a tratamiento. Es de baja disponibilidad, por su alto costo comercial. Como alternativa se documenta la plataforma Wii Balance Board (WBB) de Nintendo para registro posturográfico. Objetivo: Describir valores de normalidad en parámetros posturográficos en población chilena sin patología vestibular, usando un registro simple y accesible. Material y Método: Estudio transversal de valores referenciales en herramienta para evaluación del equilibrio. Se registraron valores posturográficos con versión adaptada del Sensory Organization Test (SOT) a adultos sanos. Mediciones con software WBB Sway Program mediante WBB. Se midieron índices somatosensorial, visual y vestibular, y patrones de control postural en ejes anteroposterior y mediolateral durante SOT-adaptado. Resultados: Se obtuvieron valores de velocidad de desplazamiento del COP, área del COP y desviaciones estándar correspondientes para 4 situaciones del SOT-adaptado de 35 sujetos entre 18-65 años, 21 mujeres, 14 hombres. Discusión: WBB permitió evaluar estos parámetros en población sana, como aproximación a determinar rangos de referencia. Esta herramienta de uso rápido y accesible constituye una alternativa útil para determinar patrones de control postural en sujetos sanos. Presentamos valores a utilizar como rango referencial en nuestra población; se sugiere utilizar estos valores como objetivo terapéutico en rehabilitación vestibular en pacientes evaluados en conjunto con otros parámetros clínico-sintomáticos.

Abstract Introduction: Posturography is a complementary method for evaluating the center of pressure (COP) displacement; it should not be used in isolation when assessing balance, but it is accepted for follow-up of the treatment response. Due to its high commercial cost and low availability, we documented the Nintendo Wii Balance Board (WBB) as an alternative for posturography. Aim: To describe the normal range of posturography parameters in the Chilean population without vestibular pathology, using a simple and accessible registry method. Material and Method: Cross-sectional study of referential values in a balance assessment tool. Posturography values were registered using an adapted version of the Sensory Organization Test (SOT) on healthy adults. Measurements with WBB Sway Program software through WBB. With adapted-SOT, somatosensory, visual and vestibular indices, as well as anterior/posterior and mediolateral axes postural control patterns, were measured. Results: Values of displacement velocity of the COP, COP area and corresponding standard deviations were obtained for 4 SOT-adapted situations from 35 subjects between 18-65 years, 21 women, 14 men. Discussion: As an approach to determine referential range values, WBB allowed to evaluate these parameters in healthy population. To determine healthy subjects postural control patterns this quick and accessible tool is a useful alternative. We present referential range values to use in our population; it is suggested to use these values as therapeutic objectives in vestibular rehabilitation in patients evaluated along with other clinical-symptomatic parameters.

Mareo postural perceptual persistente: la causa más frecuente de mareo crónico es fácil de tratar / Persistent postural-perceptual dizziness: the most frequent cause of chronic dizziness is easy to manage

RESUMEN Los trastornos vestibulares funcionales se constituyen como una de las causas más frecuentes de consulta por vértigo y trastornos del equilibrio. El mareo postural perceptual persistente (MPPP) es un síndrome recientemente definido, enmarcado en la categoría de síndromes vestibulares crónicos, que agrupa trastornos vestibulares funcionales crónicos como el vértigo postural fóbico, el malestar con el movimiento espacial, el vértigo visual y el mareo subjetivo crónico. El MPPP se manifiesta por síntomas de mareo, inestabilidad y/o vértigo no rotatorio, persistentes, exacerbados por cambios posturales, movimientos y exposición a distintos estímulos visuales. El tratamiento de este cuadro es más sencillo de lo que parece, basado en psicoeducación efectiva respecto a la patología como primer abordaje, adicionando o no rehabilitación vestibular, uso de inhibidores selectivos de la recaptación de serotonina y/o terapia cognitivo conductual. Se presentan dos casos clínicos de pacientes diagnosticados con MPPP y su respuesta a tratamiento.

ABSTRACT Functional vestibular disorders are one of the most frequent causes of consultation due to vertigo and balance disorders. Persistent postural-perceptual dizziness (PPPD) is a recently defined syndrome, categorized as a chronic vestibular syndrome, that includes functional vestibular disorders such as phobic postural vertigo, space-motion discomfort, visual vertigo and chronic subjective dizziness. PPPD manifests with dizziness, unsteadiness and/or non-spinning vertigo, which are persistent, exacerbated by postural changes, movements and exposure to various visual stimuli. PPPD treatment is simpler than it may seem initially. It is based on effective psychoeducation related to the pathology in the first place, followed, or not, by vestibular rehabilitation, use of selective serotonin reuptake inhibitors and/or cognitive behavioral therapy. We present two clinical cases of patients diagnosed with PPPD and their response to treatment.

Is eating wild rainbow trout safe? The effects of different land-uses on heavy metals content in Chile.

Cu, Mn, Fe, Zn, Cd and Pb levels were measured in liver and muscle samples of Rainbow Trout Oncorhynchus mykiss collected from three watersheds with different land-uses: native forest, exotic plantation, and agriculture in Chile, during January, April, July, and October 2012. Cd and Pb levels were not detected in the liver and muscle, probably since they are under the detection limits. Higher metal concentrations (liver-muscle tissues) were detected in samples from agriculture and exotic plantation streams, whereas trout from native forest streams had lower metal concentrations. Higher metal concentrations were detected in liver tissue compared to muscle tissue, and both negatively correlated to the length and weight of the fish. This suggest the liver had higher ability to accumulate Cu, Mn, Fe and Zn compared to muscle tissue. The concentration range of Fe and Zn recorded in the muscle are within the range reported by other authors, whereas Mn and Cu concentrations are higher than reported in the literature. However, at all sites the concentration of selected metals were below the limits permitted by current legislation (FAO), and therefore did not put the human population at risk, suggesting that is eating wild rainbow trout safe in Chile.

Ototoxicidad inducida por quimio-radioterapia basada en platinos: una revisión / Ototoxicity induced by platinum compounds-based chemoradiotherapy: a review

RESUMEN Los análogos del platino, como el cisplatino, y la radioterapia son usados de forma individual y en conjunto para el tratamiento de diversas neoplasias en población adulta y pediátrica. Sin embargo, el uso de estos tratamientos puede generar ototoxicidad, especialmente cuando son usados de forma combinada para neoplasias que comprometen cabeza y cuello, manifestándose principalmente como una hipoacusia progresiva e irreversible que compromete la calidad de vida. Diversos mecanismos han sido propuestos para explicar el daño en las estructuras auditivas generado por estos tratamientos, incluyendo la producción de especies reactivas del oxígeno y la inflamación, desencadenando muerte celular. Si bien distintas estrategias otoprotectoras han sido probadas en humanos, es aún incierta su efectividad y seguridad en combinación con los tratamientos oncológicos. El objetivo de la siguiente revisión es proporcionar una visión general y actualizada de la ototoxicidad inducida por quimio-radioterapia basada en platinos, discutiendo sus bases, características clínicas, potenciales tratamientos y estrategias preventivas que se han desarrollado en los últimos años.

ABSTRACT Platinum analogues, such as cisplatin, and radiotherapy are used separately or in combination to treat several neoplasms in pediatric and adult populations. Nonetheless, the use of these treatments may lead to ototoxicity, especially when these treatments are concomitantly used to treat head and neck cancers, which can manifest as progressive and irreversible hearing loss that decreases quality of life. Several mechanisms have been proposed in order to explain the damage to the auditory structures induced by these treatment modalities, including: reactive oxygen species production and inflammation, leading to cell death. Although several otoprotective strategies have been attempted in humans, their effectiveness and security are unclear. The objective of this review is to provide an updated and general overview on platinum-based chemoradio-therapy induced ototoxicity, discussing its basis, clinical features, potential treatments and preventive strategies developed in recent years.

Influencia del exceso de peso en el éxito de la adenoamigdalectomía en pacientes con hiperplasia adenoamigdalina sintomática / The influence of overweight in the success of adenotonsillectomy in patients with adenotonsillar symptomatic hyperplasia

Resumen Introducción: En población pediátrica con malnutrición por exceso, existe controversia respecto al rol de la hiperplasia adenoamigdalina en la etiología de los trastornos del sueño y de la efectividad de la adenoamigdalectomía sobre dicha sintomatología. Objetivo: Comparar la efectividad de la adenoamigdalectomía entre pacientes pediátricos eutróficos y con malnutrición por exceso sometidos a adenoamigdalectomía por hiperplasia adenoamigdalina, en relación a la disminución de la sintomatología. Materiales y método: Estudio retrospectivo mediante revisión de fichas clínicas entre junio de 2016 y enero de 2017 de pacientes operados de adenoamigdalectomía por hiperplasia adenoamigdalina sintomática. Se clasificaron los pacientes de acuerdo a edad y estado nutricional en 4 grupos y se evaluó la resolución de la sintomatologia mediante interrogación a padres/tutores. Resultados: Se incluyeron 98 pacientes, con una edad media de 6,3 años. 44,9% de los pacientes fueron eutróficos y 55,1% con malnutrición por exceso. El análisis estadístico entre pacientes eutróficos y aquellos con malnutrición no demostró diferencias significativas en relación a la resolución de la sintomatología. Conclusión: La adenoamigdalectomía por hiperplasia adenoamigdalina sintomática se asocia a una reducción de la frecuencia de roncopatía con pausas en pacientes pediátricos, independientemente del estado nutricional.

Abstract Introduction: In pediatric population with malnutrition by excess, the role of the adenotonsillar hyperplasia in the etiology of breathing-related sleep disorders, and the effectivity of the adenotonsillectomy for reducing symptoms remains controversial. Aim: To compare and evaluate the effectiveness of the adenotonsillectomy between eutrophic and malnutrition by excess pediatric patients submitted to adenotonsillectomy by adenotonsillar hyperplasia, regarding to symptoms resolution. Material and method: A retrospective study was performed collecting data from clinical records between June 2016 and January 2017 of patients submitted to adenotonsillectomy by symptomatic adenotonsillar hyperplasia. Patients were assigned to 4 groups according to age and nutrional status and the rate of symptoms resolution was evaluated through interrogation to parents/guardians. Results: We included 98 patients, with an average age of 6.3 years. A 44.9% of patients were eutrophic and 55.1% had malnutrition by excess. Comparing eutrophic and malnutrition by excess patients, no significant differences were observed regarding to symptoms resolution. Conclusion: The adenotonsillectomy by symptomatic adenotonsillar hyperplasia was associated to an amelioration of the rate of snoring and respiratory pauses during sleeping in pediatric patients, independently of the nutritional status.

Factors associated with uninvestigated dyspepsia in students at 4 Latin American schools of medicine: A multicenter study. / Factores asociados a dispepsia no investigada en estudiantes de 4 facultades de medicina de Latinoamérica: estudio multicéntrico.

INTRODUCTION AND AIMS: Dyspepsia is a multifactorial disease that can involve alcohol, tobacco, or nonsteroidal anti-inflammatory drug use, as well as lifestyle, diet, socioeconomic elements, or psychologic factors. The aim of the present article was to establish the frequency of uninvestigated dyspepsia and determine its associated factors in students at 4 Latin American schools of medicine. MATERIALS AND METHODS: A cross-sectional, analytic study was conducted, in which a survey made up of closed-ended questions was applied at just one point in time. The association between the variables was then analyzed. A new questionnaire for the diagnosis of dyspepsia was one of the tests utilized to diagnose uninvestigated dyspepsia. Generalized linear models were used for the bivariate and multivariate analyses, employing the Poisson model with the log link function, obtaining crude prevalence ratios, adjusted prevalence ratios, and their 95% confidence intervals. RESULTS: Of the 1,241 individuals surveyed, 54% (841) were females and the median age was 21 years (range: 19-23 years). Prevalence of uninvestigated dyspepsia was 46%. The factors that had a direct association with dyspepsia were: depression, difficulty sleeping, and coffee consumption. On the contrary, eating regularly in a boarding house and the male sex had an inverse association. CONCLUSIONS: Uninvestigated dyspepsia frequency was high in students at 4 Latin American schools. Depression, difficulty sleeping, and steady coffee drinking were factors directly associated with dyspepsia, whereas male sex and eating out at regular hours were factors with a reverse association. Therefore, we recommend that universities implement early detection programs for this highly preventable pathology.

In vitro Validation of Quantitative Light-Induced Fluorescence for the Diagnosis of Enamel Fluorosis in Permanent Teeth.

This study aimed to validate quantitative light-induced fluorescence (QLF) as a diagnostic tool for mild and moderate enamel fluorosis in permanent teeth, comparing it to visual diagnosis and histological assessment completed using polarized light microscopy (PLM). The buccal surfaces of 139 teeth were visually classified using the Thylstrup and Fejerskov Index (TFI) into sound (TFI 0; n = 17), mild (TFI 1-2; n = 69), and moderate (TFI 3-4; n = 43) fluorosis. Fluorosis was then assessed with QLF (variables ΔF, A, and ΔQ at 5-, 15-, and 30-radiance thresholds) using as reference areas the entire surface and a region of interest (ROI), identified as the most representative region of a fluorosis lesion. PLM images of longitudinal thin sections including the ROI were assessed for histological changes. Correlations among TFI, PLM, and QLF were determined. A receiver-operating characteristic curve was conducted to determine QLF's diagnostic accuracy when compared to the TFI and PLM assessments. This was used to assess the probability that the images were correctly ranked according to severity as determined by PLM and TFI. A positive correlation was found between QLF and PLM, and between QLF and TFI. QLF showed the highest sensitivity and specificity for the diagnosis of mild fluorosis. There was also a strong agreement between TFI and PLM. The selection of a ROI resulted in a stronger correlation with TFI and PLM than when the entire surface was used. The study results indicate that defining an ROI for QLF assessments is a valid method for the diagnosis of mild and moderate enamel fluorosis.

The fusogenic peptide HA2 impairs selectivity of CXCR4-targeted protein nanoparticles.

We demonstrate here that the genetic incorporation of the fusogenic peptide HA2 into a CXCR4-targeted protein nanoparticle dramatically reduces the specificity of the interaction between nanoparticles and cell receptors, a factor to be considered when designing tumor-homing drug vehicles displaying endosomal-escape agents. The loss of specificity is concomitant with enhanced cell penetrability.

Fish diversity in the Río de la Plata and adjacent waters: an overview of environmental influences on its spatial and temporal structure.

The fish diversity and the main environmental factors affecting the spatial distribution of species, life history stages and community structure in the Río de la Plata (RdP) and adjacent waters are reviewed and analysed, with emphasis on the functional guild classification. The functional guild classification indicated that most species in the RdP were marine stragglers, zoobenthivores and oviparous species, although the biomass was dominated by estuarine species. Salinity had a stronger influence than temperature on the spatial pattern for all life stages, shallower and fresher waters are the preferred habitats of neonates and juveniles. During the breeding season (spring-summer), adults showed an intrusion into the inner part of RdP or to its adjacent nearshore waters from the offshore waters for spawning or mating, respectively. Variations in river discharge and wind patterns greatly affected the spatial extent of estuarine water, which ultimately influenced the domain of the main life-history stages (juveniles or adults) for both marine and estuarine fishes, as well as species and fish assemblage composition. The strong environmental gradient restricts some species and life-history stages to a particular section and defines three main fish assemblage areas. The composition of the fish assemblage is indicative of the recruitment of freshwater and marine species to the estuary in opposite ways, determined by the vertical stratification. Seasonal changes in the species composition were related to migration as a result of salinity and temperature variations and reproductive migrations to spawning and mating areas. This overview reveals that the RdP is under environmental variations that are likely to produce modifications to fish distribution and abundance that affect its fisheries. This context plus fish stock declines and changes in exploitation patterns could amplify the magnitude of the variations in the fisheries resources availability and affect the sustainability of fishing communities.

Reproductive and population parameters of spiny dogfish Squalus acanthias in the south-western Atlantic Ocean.

The objective of this study was to estimate reproductive and population parameters of the spiny dogfish Squalus acanthias for the south-western Atlantic Ocean. In total, 2714 specimens (1616 males and 1098 females) were collected from surveys carried out using research vessels. Males ranged from 225 to 861 mm total length (LT ) and females from 235 to 925 mm LT . The size at maturity of females (651 mm) was significantly greater than that of males (565 mm). The maximum proportion of mature individuals (Pmax ) of the gestation ogive was <1, which indicates that a proportion of mature females was not in gestation. This inactivity may be explained by the occurrence of resting periods between cycles or by the asynchrony of the reproductive cycle. The estimated Pmax for the maternity ogive suggested that about one third of mature females were in the maternity stage (i.e. with embryos >156 mm). The temporal and spatial co-occurrence of non-gravid adult females at different stages of ovarian development, as well as gravid females at all embryonic development stages would indicate that the female reproductive cycle in the south-western Atlantic Ocean is asynchronous. The results indicate that S. acanthias is susceptible to fishing pressure on account of its length at maturity, extended reproductive cycles and low fecundity.

Trophic ecology of yellownose skate Zearaja chilensis, a top predator in the south-western Atlantic Ocean.

The diet and trophic level (TL ) of the yellownose skate Zearaja chilensis in the south-western Atlantic Ocean (35°-54° S), and how these varied in relation to body size, sex, maturity stage, depth and region were determined by analysis of stomach contents. From 776 specimens analysed, 671 (86·5%) ranging from 180 to 1190 mm total length (LT ) had prey in their stomachs. The diet was dominated by fishes, mainly the notothenioid Patagonotothen ramsayi and the Argentine hake Merluccius hubbsi. The consumption of fishes and crabs increased with increasing predator size, and these preys were more important in the north than in the south. Isopods and other crustaceans were consumed more in the south and their consumption decreased as the size of Z. chilensis increased. The TL of Z. chilensis increased with LT from 4·29 to 4·59 (mean 4·53), confirming their ecological role as a top predator. The small and large size classes exhibited a low diet overlap and the highest spatial segregation, whereas medium and large specimens had higher co-occurrence and dietary overlap indices. A clear distinction in tooth shape was noted between sexes in adult specimens, with males having longer cusps. This sexual heterodonty may be related to reproductive behaviour, increasing the grasping ability of males during courtship, because there were no differences in diet between the sexes.

Concurrent psychological stress and infectious colitis is key to sustaining enhanced peripheral sensory signaling.

BACKGROUND: The development of postinfectious-irritable bowel syndrome is associated with psychological stress but this relationship is poorly understood. The mouse Citrobacter rodentium model enhances the postinfectious excitability of colonic nociceptors, which can be further amplified by water-avoidance stress (WAS). This study tested whether concurrent infectious colitis and chronic stress enhance and sustain nociceptor excitability more than stress after resolution of infection. METHODS: Male C57 mice were gavaged with C. rodentium. WAS (1 h/day) was performed at different time-points relative to the infection. After the final session of WAS, T9-T13 colonic-projecting DRG neurons were isolated, cultured overnight and patch-clamped to assess excitability. To investigate potential mechanisms, histological damage scores and colonic cytokine production were assessed. KEY RESULTS: WAS more than 30 days after C. rodentium infection produced no greater DRG excitability than WAS in uninfected mice. However, when overlapped with chronic stress (3 sessions of WAS; 7 days before, 9 days during and 9 days after C. rodentium or sham gavage), C. rodentium significantly enhanced DRG excitability vs saline-gavaged chronically stressed mice. Bodyweights and colonic damage scores were unchanged. Both WAS and C. rodentium gavage were found to significantly alter colonic cytokines at postinfection day 30. CONCLUSIONS & INFERENCES: Chronic stress and infectious colitis combine in an additive manner to heighten and prolong the sensitivity of visceral nociceptors. The effect relies on temporal coincidence of stress and infection, does not involve substantial exacerbation of inflammation, and may involve combined direct stress hormone and immune signaling on DRG neurons.