Sonic Hedgehog signalling in the regulation of barrier tissue homeostasis and inflammation

Epithelial barrier tissues such as the skin and airway form an essential interface between the mammalian host and its external environment. These physical barriers are crucial to prevent damage and disease from environmental insults and allergens. Failure to maintain barrier function against such risks can lead to severe inflammatory disorders, including atopic dermatitis and asthma. Here, we discuss the role of the morphogen Sonic Hedgehog in postnatal skin and lung and the impact of Shh signalling on repair, inflammation and atopic disease in these tissues

Evaluation of navigability in skid-steer mobile robots with passive trailers moving on sloping terrain

[EN] The use of trailers allows robots to increase their load capacity to perform multiple tasks, but their use carries multiple risks. In this research, three metrics are developed to assess the navigability of robots with coupled trailers when moving at low speeds on inclined surfaces: an index that predicts the initiation of rollover in the robot or trailers; another index that estimates the start of the total slip due to the slopes of the terrain, either in the robot or the trailers; and finally, an index that quantifies the robot's ability to address itself and follow a path. These three metrics were developed based on the reaction forces of the wheels with the ground and were validated through  simulation and experimental tests using a Skid Steer robot called Lázaro, demonstrating their effectiveness in estimating the risk condition for which they were designed.[ES] El uso de remolques permite a los robots aumentar su capacidad de carga para realizar múltiples tareas, pero su uso conlleva múltiples riesgos. En esta investigación, se desarrollan tres métricas para evaluar la navegabilidad de robots con remolques acoplados cuando se mueven a bajas velocidades sobre superficies inclinadas: un í­ndice que predice el inicio del vuelco en el robot o los remolques; otro í­ndice que estima el inicio del deslizamiento total debido a las inclinaciones del terreno, ya sea en el robot o los remolques; y finalmente, un í­ndice que cuantifica la capacidad del robot para direccionarse y seguir una trayectoria. Estas tres métricas fueron desarrolladas con base en las fuerzas de reacción de las ruedas con el suelo y fueron validados a través de simulación y pruebas experimentales utilizando un robot Skid Steer llamado Lázaro, demostrándose su efectividad al estimar la condición de riesgo para la cual fueron diseñados.Este trabajo ha sido realizado parcialmente gracias al apoyo del Decanato de Investigación de la Universidad Nacional Experimental del Táchira bajo los proyectos No. 01-025-2016 y 01-004-2019.García, JM.; Yánez, P.; Martínez, JE. (2022). Evaluación de la navegabilidad en robots móviles skid-steer con remolques pasivos moviéndose sobre terrenos inclinados. Revista Iberoamericana de Automática e Informática industrial. 20(1):13-24. https://doi.org/10.4995/riai.2022.17161132420

Primer registro de Litomosoides pardinasi (Nematoda: Onchocercidae) en roedores nativos y exóticos de Chile

Litomosoides pardinasi es registrada por primera vez en roedores nativos y exóticos de Chile. La especie Litomosoides pardinasi, parásita de Phyllotis xanthopygus y Oligoryzomys longicaudatus en la Patagonia Argentina, fue encontrada en Chile parasitando la cavidad torácica y abdominal de O. longicaudatus (prevalencia (P)= 18.9%, intensidad media (MI)= 57.3) y de Phyllotis darwini (P= 4.2%, MI= 10), y la cavidad abdominal del roedor exótico Rattus rattus (P= 1.24%; MI= 22.5). La P total en roedores nativos de Chile fue significativamente menor que la P de Argentina, en tanto la MI total fue significativamente mayor. La P y MI de L. pardinasi en O. longicaudatus de Chile y Argentina no mostraron diferencias significativas; la P en P. darwini de Chile fue significativamente menor que la de P. xanthopygus de Argentina y que la de O. longicaudatus de Chile. Considerando la distribución de las especies de Litomosoides entre los sigmodontinos, estos resultados apoyan la hipótesis que L. pardinasi está bien establecida en O. longicaudatus y que posiblemente haya sido recientemente adquirida por P. darwini y R. rattus. Así, L. pardinasi colonizó primero a la Tribu Oryzomyini y posteriormente por un fenómeno de cambio de hospedero a la Tribu Phyllotini y a R. rattus.We report the first record of Litomosoides pardinasi in native and exotic rodents from Chile. Litomosoides pardinasi, described in the Argentine Patagonia parasitizing Phyllotis xanthopygus and Oligoryzomys longicaudatus, was found in Chile parasitizing the peritoneal and thoracic cavities of O. longicaudatus (prevalence (P)= 18.9%, mean intensity (MI)= 57.3) and Phyllotis darwini (P= 4.2%, MI= 10), and in the peritoneal cavity of Rattus rattus (P= 1.24%; MI= 22.5). Total P in native rodents from Chile was significantly lower than in Argentina, while the total MI was higher. Prevalence and MI of L. pardinasi in O. longicaudatus from Chile and Argentina showed non-significant differences; prevalence in P. darwini from Chile was significantly lower than in P. xanthopygus from Argentina and than in Chilean O. longicaudatus. Our results, together with those from Argentina, support the hypothesis that L. pardinasi is well established in O. longicaudatus, but seems to be recently acquired by P. darwini and the exotic R. rattus. Considering the known host distribution of Litomosoides species among the sigmodontines, our results also support the hypothesis that L. pardinasi first colonized the Oryzomyini tribe and later, by different phenomena of host-switching, colonized the Phyllotini tribe and the exotic R. rattus.Fil: Landaeta Aqueveque, Carlos. Universidad de Concepción; ChileFil: Notarnicola, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Correa, Juana P.. Universidad de Chile; ChileFil: Yánez Mesa, Andrea. Universidad de Chile; ChileFil: Henriquez, AnaLía. Universidad Santo Tomás; ChileFil: Cattan, Pedro E.. Universidad de Chile; ChileFil: Botto Mahan, Carezza. Universidad de Chile; ChileFil: Torres Pérez, Fernando. Pontificia Universidad Catolica de Valparaiso; Chil

Modelos y análisis para datos de degradación

La degradación es una debilidad que eventualmente puede causar la falla (e. g., el desgaste que sufren los neumáticos de un automóvil). Cuando es posible medirla, esta puede proporcionar mayor información que los datos de tiempo de falla, para propósitos de determinación y mejoramiento de la confiabilidad de un producto. Este artículo es de carácter divulgativo y desarrolla técnicas que son propuestas por Meeker y Escobar (1998). Se cree importante hacer conocer este tópico, hoy en la frontera de la Teoría de Confiabilidad (Lawless 2000)). En este trabajo se compara el análisis clásico aproximado de degradación con el modelo de degradación explícito. Estos últimos modelos implican la utilización de modelos físicos de degradación a los cuales se les introduce efectos aleatorios. Se implementan las técnicas para la estimación de modelos mixtos en S-PLUS siguiendo a Pinheiro y Bates (2000) y se utiliza el bootstrap para intervalos de confianza.Degradation is a weakness that eventually can cause failure (e.g. car tire wear). When it is possible to measure degradation, such measures often provide more information than failure-time data for purposes of assessing and improving product reliability. This is a paper which mainly pretends to divulge techniques that had been developed by Meeker and amp; Escobar (1998). We think it is worth to make this topics known, because they are in the research frontier of the Reliability Theory (Lawless 2000). We compare in this work the explicit degradation models with the approximate degradation analysis. The explicit degradation model requires specific models developed by engineers and physical scientists, which are treated as mixed models with random effects. To obtain ML estimates we use S-PLUS following Pinheiro and amp; Bates (2000), and also use bootstrap confidence intervals

Foxa1 and Foxa2 in thymic epithelial cells (TEC) regulate medullary TEC and regulatory T-cell maturation

The Foxa1 and Foxa2 transcription factors are essential for mouse development. Here we show that they are expressed in thymic epithelial cells (TEC) where they regulate TEC development and function, with important consequences for T-cell development. TEC are essential for T-cell differentiation, lineage decisions and repertoire selection. Conditional deletion of Foxa1 and Foxa2 from murine TEC led to a smaller thymus with a greater proportion of TEC and a greater ratio of medullary to cortical TEC. Cell-surface MHCI expression was increased on cortical TEC in the conditional Foxa1Foxa2 knockout thymus, and MHCII expression was reduced on both cortical and medullary TEC populations. These changes in TEC differentiation and MHC expression led to a significant reduction in thymocyte numbers, reduced positive selection of CD4+CD8+ cells to the CD4 lineage, and increased CD8 cell differentiation. Conditional deletion of Foxa1 and Foxa2 from TEC also caused an increase in the medullary TEC population, and increased expression of Aire, but lower cell surface MHCII expression on Aire-expressing mTEC, and increased production of regulatory T-cells. Thus, Foxa1 and Foxa2 in TEC promote positive selection of CD4SP T-cells and modulate regulatory T-cell production and activity, of importance to autoimmunity

Germinal matrix hemorrhage: can be detected effectively

La hemorragia de la matriz germinal corresponde a un evento cerebrovascular originado en sus vasos sanguíneos, es prevalente en los prematuros y es la primera causa de mortalidad infantil en Ecuador; su inadecuado diagnóstico tiene un importante impacto en el neurodesarrollo de los prematuros y puede generar secuelas graves que pueden ser mayores conforme al grado de prematuridad, especialmente en prematuros con un peso de 500 a 750 g al nacimiento. Una de las principales herramientas para diagnosticar la hemorragia de la matriz es el ultrasonido transfontanelar que es fundamental en la detección y manejo temprano la situación, se debe considerar que requiere de un radiólogo experimentado para identificar e interpretar los hallazgos. Los factores de riesgo asociados son: la edad gestacional, el peso bajo al nacer, la puntuación baja del test de Apgar, la acidosis y la asfixia neonatal. Los factores que están implicados en la hemorragia pueden ser: intravasculares, vasculares y extravasculares. Los grados pueden ir del Grado I (masa hiperecogénica por la presencia de coágulos, el plexo coroideo luce engrosado en la región del trígono), Grado II (en el que la hemorragia se extiende hacia la cisterna magna lo que incrementa el riesgo de hidrocefalia), Grado III en el que el coágulo se volverá más anecoico con el tiempo, la presencia de sangre en el LCR puede producir una ventriculitis química) y Grado IV (con hipercogenecidad paraventricular con afectación de lóbulos frontales y parietales). El ultrasonido transfontanelar puede detectar varias lesiones cerebrales en el recién nacido prematuro entre estas la hemorragia de la matriz germinal y la leucomalacia periventricular. La causa principal de la leucomalacia son los eventos hipóxicos-isquémicos, por lo que las lesiones predominan en la sustancia blanca periventricular. Se recomienda el uso de esta técnica para el diagnóstico oportuno de la hemorragia en los recién nacidos que presenten factores de riesgo.The germinal matrix hemorrhage corresponds to a cerebrovascular event originated in its blood vessels, it is prevalent in premature babies and is the first cause of infant mortality in Ecuador; Its inadequate diagnosis has an important impact on the neurodevelopment of premature infants and can generate serious sequelae that may be greater depending on the degree of prematurity, especially in premature infants weighing 500 to 750 g at birth. One of the main tools to diagnose womb bleeding is transfontanelar ultrasound, which is fundamental in the detection and early management of the situation. It should be considered that it requires an experienced radiologist to identify and interpret the findings. Some associated risk factors are: gestational age, low birth weight, low Apgar score, acidosis, and neonatal asphyxia. The factors that are involved in bleeding can be: intravascular, vascular and extravascular. The degrees can range from Grade I (hyperechogenic mass due to the presence of clots, the choroid plexus looks thickened in the trigone region), Grade II (in which the hemorrhage extends to the cisterna magna, which increases the risk of hydrocephalus) , Grade III in which the clot will become more anechoic over time, the presence of blood in the CSF can cause chemical ventriculitis) and Grade IV (with paraventricular hypercogenecity with involvement of the frontal and parietal lobes). Transfontanelar ultrasound can detect various brain lesions in the premature newborn, including bleeding from the germ matrix and periventricular leukomalacia. The main cause of leukomalacia is hypoxic-ischemic events, so that the lesions predominate in the periventricular white matter. The use of this technique is recommended for the timely diagnosis of bleeding in newborns with risk factors

Dyslipidemias and stroke prevention: recommendations of the Study Group of Cerebrovascular Diseases of the Spanish Society of Neurology

Objetivo: Actualizar las recomendaciones de la Sociedad Española de Neurología para la prevención del ictus, tanto primaria como secundaria, en pacientes con dislipidemia. Desarrollo: Se ha realizado una revisión sistemática en Pubmed evaluando los principales aspectos relacionados con el manejo de las dislipidemias en la prevención primaria y secundaria del ictus, elaborándose una serie de recomendaciones relacionadas con los mismos. Conclusiones: En prevención primaria se recomienda determinar el riesgo vascular del paciente con el fin de definir los objetivos de LDLc. En prevención secundaria tras un ictus de origen aterotrombótico se recomienda un objetivo de LDLc < 55 mg/dl, mientras que en ictus isquémicos de origen no aterotrombótico, dado que su relación con dislipidemias es incierta, se establecerán los objetivos en función del grupo de riesgo vascular de cada paciente. Tanto en prevención primaria como secundaria las estatinas son los fármacos de primera elección, pudiendo asociarse ezetimiba y/o inhibidores de PCSK9 en aquellos casos que no alcancen los objetivos terapéuticosObjective We present an update of the Spanish Society of Neurology's recommendations for prevention of both primary and secondary stroke in patients with dyslipidaemia. Development We performed a systematic review to evaluate the main aspects of the management of dyslipidaemias in primary and secondary stroke prevention and establish a series of recommendations. Conclusions In primary prevention, the patient's vascular risk should be determined in order to define target values for low-density lipoprotein cholesterol. In secondary prevention after an atherothrombotic stroke, a target value < 55 mg/dL is recommended; in non-atherothombotic ischaemic strokes, given the unclear relationship with dyslipidaemia, target value should be established according to the vascular risk group of each patient. In both primary and secondary prevention, statins are the drugs of first choice, and ezetimibe and/or PCSK9 inhibitors may be added in patients not achieving the target valu

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P &lt; 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P &lt; 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic