161 research outputs found
Curcumin Pretreatment Induces Nrf2 and an Antioxidant Response and Prevents Hemin-Induced Toxicity in Primary Cultures of Cerebellar Granule Neurons of Rats
Curcumin is a bifunctional antioxidant derived from Curcuma longa. This study identifies curcumin as a neuroprotectant against hemin-induced damage in primary cultures of cerebellar granule neurons (CGNs) of rats. Hemin, the oxidized form of heme, is a highly reactive compound that induces cellular injury. Pretreatment of CGNs with 5–30 μM curcumin effectively increased by 2.3–4.9 fold heme oxygenase-1 (HO-1) expression and by 5.6–14.3-fold glutathione (GSH) levels. Moreover, 15 μM curcumin attenuated by 55% the increase in reactive oxygen species (ROS) production, by 94% the reduction of GSH/glutathione disulfide (GSSG) ratio, and by 49% the cell death induced by hemin. The inhibition of heme oxygenase system or GSH synthesis with tin mesoporphyrin and buthionine sulfoximine, respectively, suppressed the protective effect of curcumin against hemin-induced toxicity. These data strongly suggest that HO-1 and GSH play a major role in the protective effect of curcumin. Furthermore, it was found that 24 h of incubation with curcumin increases by 1.4-, 2.3-, and 5.2-fold the activity of glutathione reductase, glutathione S-transferase and superoxide dismutase, respectively. Additionally, it was found that curcumin was capable of inducing nuclear factor (erythroid-derived 2)-like 2 (Nrf2) translocation into the nucleus. These data suggest that the pretreatment with curcumin induces Nrf2 and an antioxidant response that may play an important role in the protective effect of this antioxidant against hemin-induced neuronal death
Numerical analysis of the over-expanded flow in the experimental conical nozzle ULA-1B out of design
En las toberas supersónicas, ocurren diferentes patrones de flujo y su comportamiento está influenciado por las geometrías de las superficies internas de las paredes. En el presente trabajo se simula en 2D el campo de flujo sobrexpandido en la tobera cónica experimental ULA-1B fuera de diseño, para dos casos de longitudes de garganta: Lg=15mm y Lg=1mm; con el fin de analizar el campo de número de Mach, presión y temperatura. Se empleó el código ANSYS-Fluent y se aplicó el modelo RANS; las ecuaciones gobernantes: conservación de la masa, cantidad de movimiento, energía, y estado; así como el modelo de turbulencia de Menter y la ecuación de Sutherland para la viscosidad en función de la temperatura. En la sección de la garganta de mayor longitud, los resultados mostraron choques oblicuos, fluctuaciones de velocidad, presión y temperatura; para la garganta de menor longitud no hubo fluctuaciones; para ambos casos, el flujo en la divergente presentó picos de velocidad en el rango de 2,5-3 Mach. Se concluye que, para la menor longitud de garganta el flujo se acelera sin perturbaciones en dicha sección; en la divergente se presenta un chorro supersónico y una separación de flujo In supersonic nozzles, different flow patterns occur and their behavior is influenced by the geometries of the internal surfaces of the walls. In the present work, the over-expanded flow field is simulated in 2D in the experimental ULA-1B conical nozzle out of design, for two cases of throat lengths:Lg =15 mm and Lg= 1 mm; in order to analyze the field of Mach number, pressure and temperature. The ANSYS-Fluent code was used and the RANS model was applied; the governing equations: conservation of mass, momentum, energy, and state; as well as the Menter turbulence model and the Sutherland equation for the viscosity as a function of temperature. In the longest throat section, the results showed oblique shocks, speed, pressure and temperature fluctuations; for the shorter throat there were no fluctuations; for both cases, the flow in the divergent presented speed peaks in the range of 2,5 - 3 Mach. It is concluded that, for the shorter throat length, the flow accelerates without disturbances in said section; in the divergent there is a supersonic jet and flow separation
A new locality with ctenochasmatid pterosaurs (Pterosauria: Pterodactyloidea) in the Atacama Desert, Northern Chile
We describe a new locality with ctenochasmatid pterosaurs found in a tidal estuarine paleoenvironment of the Quebrada Monardes Formation (Lower Cretaceous). The new locality, which is named “Cerro Tormento”, is in Cerros Bravos in the northeast Atacama region, Northern Chile. Here, we describe four cervical vertebrae, one of them belonging to a small individual, the impression of a right scapulocoracoid, a left coracoid, an impression of a left humerus, an incomplete left humerus, a distal fragment of the right humerus, and impressions of a left femur and tibiotarsus. The presence of three humeri and a cervical vertebra belonging to a small pterosaur indicate that these materials represent more than one individual. The cervical vertebrae present diagnostic traits shared with ctenochasmatid pterosaurs, such as elongated vertebral centra, with integrated neural arch, low neural spines, and dorsally located neural canal. It is currently not possible to determine if there are one or more species represented. This finding is the second geographic occurrence of pterosaurs of the clade Ctenochasmatidae in the Atacama region, although it is currently uncertain if ctenochasmatids from both locations were contemporaneous. This suggests that the clade Ctenochasmatidae was widespread in what is now northern Chile. In addition, the presence of bones belonging to more than one individual preserved in Cerro Tormento suggest that pterosaur colonies were present at the southwestern margin of Gondwana during the Early Cretaceous.Fil: Alarcón Muñoz, Jhonatan Andrés. Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas. Departamento de Geología; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Codorniú, Laura. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Geología; ArgentinaFil: González, Edwin. Servicio Nacional de Geología y Minería; ChileFil: Suárez, Mario E.. Atacama Fosil Research; ChileFil: Suárez, Manuel. Universidad Andrés Bello; ChileFil: Vicencio Campos, Omar. Atacama Fosil Research; ChileFil: Soto Acuña, Sergio. Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas. Departamento de Geología; ChileFil: Kaluza, Jonatan Ezequiel. Fundación de Historia Natural Félix de Azara; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vargas, Alexander O.. Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas. Departamento de Geología; ChileFil: Rubilar Rogers, David. Museo Nacional de Historia Natural de Chile; Chil
El impacto del embarazo en el desenlace de pancreatitis biliar aguda
Antecedentes y objetivo: La pancreatitis aguda es una de las condiciones gastrointestinalesmás comunes que requieren hospitalización. Aunque su aparición durante el embarazo es pococomún, representa un reto médico. Actualmente, no existen estudios que comparen los desen-laces clínicos entre mujeres embarazadas con pancreatitis aguda y pacientes no embarazadascon pancreatitis aguda. Nuestro objetivo fue comparar las características y desenlaces clínicosde las mujeres embarazadas y no embarazadas con pancreatitis aguda.Métodos: Realizamos un estudio retrospectivo que incluyó a todas las pacientes admitidas ennuestro hospital con pancreatitis aguda durante un periodo de 10 a˜nos. Se evaluaron y compa-raron los datos demográficos, las características generales y los desenlaces clínicos entre lasmujeres embarazadas y las mujeres no embarazadas con pancreatitis aguda, con una razón de1:5.Resultados: Se trató a 27 pacientes embarazadas con pancreatitis aguda en un periodo de10 a˜nos. La etiología fue biliar en el 96% de los casos y en el 3.4% de los casos la causa fuehipertrigliceridemia (un paciente). La edad media de las pacientes fue de 26.2 a˜nos (rango de15-36 a˜nos). La causa principal de la pancreatitis aguda fue la enfermedad biliar (96%). Laspacientes en el grupo de estudio cursaban su primer, segundo o tercer trimestre del embarazo,con una distribución del 7.4, el 33.3 y el 59.3%, respectivamente. En la comparación entrepacientes embarazadas y no embarazadas con pancreatitis aguda, no existieron diferencias enedad, tiempo de hospitalización (7.37 vs. 10.8, p = 0.814), gravedad (grave, 3.7% vs. 16.7%,p = 0.79), complicaciones locales (0% vs. 1.9%, p = 0.476) o mortalidad (0% vs. 1.9%, p = 0.476).
Conclusiones: La evolución clínica de ambos grupos con pancreatitis biliar aguda fue similar,con baja morbimortalidad
Erosivity indicators based on rainfall in Northwestern Mexico
This study is motivated by the problem of erosivity (R), exacervated in semiarid zones by intense seasonal storms. The purpose was to estimate the spatial variation of R in a coastal area covering 37500 km2 which is one of the most important agricultural areas in northwestern Mexico. Four methods were used. Rainfall data from 11 SMNCONAGUA weather stations (from 1966 to 2013) were used to calculate R. The annual average R1 was 1181.08, and R2 was 1084.51 MJ mm ha–1 h–1 with ranges of 2.35–5220.55 and 2.93–4711.38 MJ mm ha–1 h–1. Statistical tests showed that a transformation of the data of the form y = log (x), was appropriate for an ANOVA analysis of the data. The value of the test statistic was F = 1.77 with p = 0.149, showing interdependence between the indicators P (α = 0.05). The values of the correlation coefficients for the data were P vs. R1 = 0.96, P vs. R2 = 0.99, P vs. AIm = 0.98, P vs. MFI = 0.99. The classification of risk in this region showed that 2017.5 km2 of the study area was at a very high risk of rain erosion, 2407.5 km2 under high risk, 5662.5 km2 under medium to high risk, and 14250 km2 under low risk. The results are shown on 1:10,000 maps. Results are a set of useful information for soil management programs and for cultivation planning that takes the seasonal variation of R into account in this region where large volumes of extensive crops are grown.
Dose-effect calibration curve for high X-ray doses using the Calyculin-A chromosome premature condensation assay
Purpose: This article shows the results of the Cytogenetics Laboratory of the Health Research Institute (INISA) to develop a dose-effect calibration curve with the Calyculin-A chemical induction premature condensation assay to estimate high doses of X-ray exposure. Methods: to create the calibration curve, peripheral blood samples from two participants (one female and one male) were exposed to X-rays at six different dose points ranging from 0 to 17.5 Gy in vitro. The irradiated blood was cultured for 48 hours according to international protocols, and the resulting chromosome rings were recorded. We used BioDoseTools software to calculate the coefficients for the calibration curve. Results: The coefficients of the curve are α: 0.028±0.001 and C: 0.001±0.001. These coefficients have similar values to those reported internationally. The curve was validated by calculating an unknown dose exposed to 6 Gy; the estimated dose was 5.651 ± 0.636 Gy, with no statistically significant differences between the dose delivered and the estimated dose. Conclusions: The INISA Biological Dosimetry Service can use the curve obtained to assess absorbed doses in cases of suspected overexposure to high X-ray doses
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016
Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study
Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak.
Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study.
Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM.
Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide
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