Activation of Fgf4 Gene Expression in the Myotomes Is Regulated by Myogenic bHLH Factors and by Sonic Hedgehog

AbstractThe Fgf4 gene encodes an important signaling molecule which is expressed in specific developmental stages, including the inner cell mass of the blastocyst, the myotomes, and the limb bud apical ectodermal ridge (AER). Using a transgenic approach, we previously identified overlapping but distinct enhancer elements in the Fgf4 3′ untranslated region necessary and sufficient for myotome and AER expression. Here we have investigated the hypothesis that Fgf4 is a target of myogenic bHLH factors. We show by mutational analysis that a conserved E box located in the Fgf4 myotome enhancer is required for Fgf4-lacZ expression in the myotomes. A DNA probe containing the E box binds MYF5, MYOD, and bHLH-like activities from nuclear extracts of differentiating C2-7 myoblast cells, and both MYF5 and MYOD can activate gene expression of reporter plasmids containing the E-box element. Analyses of Myf5 and MyoD knockout mice harboring Fgf4-lacZ transgenes show that Myf5 is required for Fgf4 expression in the myotomes, while MyoD is not, but MyoD can sustain Fgf4 expression in the ventral myotomes in the absence of Myf5. Sonic hedgehog (Shh) signaling has been shown to have an essential inductive function in the expression of Myf5 and MyoD in the epaxial myotomes, but not in the hypaxial myotomes. We show here that expression of an Fgf4-lacZ transgene in Shh−/− embryos is suppressed not only in the epaxial but also in the hypaxial myotomes, while it is maintained in the AER. This suggests that Shh mediates Fgf4 activation in the myotomes through mechanisms independent of its role in the activation of myogenic factors. Thus, a cascade of events, involving Shh and bHLH factors, is responsible for activating Fgf4 expression in the myotomes in a spatial- and temporal-specific manner

Purificación, secuenciación y caracterización de un péptido presente en el intestino de Triatoma infestans que estimula la adenilil ciclasa de Trypanosoma cruzi y promueve la metaciclogénesis

Fil: Fraidenraich y Waisman, Diego. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Imaging of VSOP Labeled Stem Cells in Agarose Phantoms with Susceptibility Weighted and T2* Weighted MR Imaging at 3T: Determination of the Detection Limit

Objectives: This study aimed to evaluate the detectability of stem cells labeled with very small iron oxide particles (VSOP) at 3T with susceptibility weighted (SWI) and T2* weighted imaging as a methodological basis for subsequent examinations in a large animal stroke model (sheep). Materials and Methods We examined ovine mesenchymal stem cells labeled with VSOP in agarose layer phantoms. The experiments were performed in 2 different groups, with quantities of 0–100,000 labeled cells per layer. 15 different SWI- and T2*-weighted sequences and 3 RF coils were used. All measurements were carried out on a clinical 3T MRI. Images of Group A were analyzed by four radiologists blinded for the number of cells, and rated for detectability according to a four-step scale. Images of Group B were subject to a ROI-based analysis of signal intensities. Signal deviations of more than the 0.95 confidence interval in cell containing layers as compared to the mean of the signal intensity of non cell bearing layers were considered significant. Results: Group A: 500 or more labeled cells were judged as confidently visible when examined with a SWI-sequence with 0.15 mm slice thickness. Group B: 500 or more labeled cells showed a significant signal reduction in SWI sequences with a slice thickness of 0.25 mm. Slice thickness and cell number per layer had a significant influence on the amount of detected signal reduction. Conclusion: 500 VSOP labeled stem cells could be detected with SWI imaging at 3 Tesla using an experimental design suitable for large animal models

Simulation of PV module generation in the city of Salta using statistically representative values of solar radiation and temperature adapted from satellite databases

En este trabajo se propone una metodología para estimar el valor de energía generado por un módulo FV cualquiera, inclinado y orientado, bajo condiciones estadísticamente representativas de radiación solar y temperatura ambiente, en la ciudad de Salta (Argentina). Para ello primero se prepara una base de datos de irradiancia solar global y de temperatura ambiente estadísticamente representativa para el sitio, utilizando un procedimiento de Adaptación al Sitio mejorado, usando datos medidos en el sitio especifico. Se aplica luego el modelo de Engerer para estimar la fracción difusa con lo que se estima la componente directa y difusa de la irradiancia solar global, considerando los aportes de cada componente sobre el plano del módulo. Se aplican estos datos a un modelo de modulo FV basado en diferencia de valores de potencia eléctrica STC afectado por temperatura de modulo. La diferencia de los valores GHI anuales adaptados y sin adaptar es del 8.35%, lo que genera una diferencia del 7.34% en la energía eléctrica generada por un módulo de 450 Wp y 2.21 m² de área, inclinado 24° y orientado al norte. Este procedimiento es el primer paso para generar una herramienta que permita estimar la generación FV domiciliaria en la ciudad de Salta, y posteriormente la previsión de producción.In this work, a methodology is proposed to obtain the value of energy generated by any PV module, tilted and oriented, under statistically representative conditions of solar radiation and ambient temperature, in the city of Salta (Argentina). To do this, a statistically representative database of global solar irradiance GHI and ambient temperature Tamb is first prepared for the site, using an improved Site Adaptation procedure using data measured at the specific site. Engerer model is then applied to estimate the diffuse fraction with which the direct and diffuse component of the global solar irradiance is estimated, considering the contributions of each component on the plane of the module. These data are applied to a PV module model based on difference in electrical power values STC affected by module temperature. The difference between the adapted and unadjusted annual GHI values is 8.35%, which generates a difference of 7.34% in the electrical energy generated by a module of 450 Wp and 2.21 m² of area, inclined 24° and facing north. This procedure is the first step to generate a tool to estimate residential PV generation in the city of Salta, and subsequently the production forecast.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Caracterização de módulos fotovoltáicos orgânicos (P3HT:PCBM) com radiação solar

Los principales parámetros que influyen en la eficiencia de módulo solar orgánico de capa activa P3HT:PCBM, se analizan en este trabajo en condiciones reales de la radiación solar. Los experimentos se llevaron a cabo en la Universidad Federal de Pernambuco en Recife, Pernambuco, Brasil. Por medio del análisis de los resultados se puede observar el comportamiento de los parámetros eléctricos de un módulo orgánico en función de la irradiación y, por tanto, entender cómo funcionaría un sistema que utiliza la electricidad generada a partir de paneles orgánicos.The main parameters that influence the efficiency of organic solar module active layer P3HT:PCBM, are analyzed in this work in real conditions of solar radiation. The experiments were conducted at the Federal University of Pernambuco in Recife, Pernambuco, Brazil. Through analysis of the results, it is possible to observe the behavior of the electrical parameters of an organic module depending on the irradiance and thus, better understand how it would work in a system using electricity generated from organic panels.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

An alternative mitophagy pathway mediated by Rab9 protects the heart against ischemia

Energy stress, such as ischemia, induces mitochondrial damage and death in the heart. Degradation of damaged mitochondria by mitophagy is essential for the maintenance of healthy mitochondria and survival. Here, we show that mitophagy during myocardial ischemia was mediated predominantly through autophagy characterized by Rab9-associated autophagosomes, rather than the well-characterized form of autophagy that is dependent on the autophagy-related 7 (Atg) conjugation system and LC3. This form of mitophagy played an essential role in protecting the heart against ischemia and was mediated by a protein complex consisting of unc-51 like kinase 1 (Ulk1), Rab9, receptor-interacting serine/ thronine protein kinase 1 (Rip1), and dynamin-related protein 1 (Drp1). This complex allowed the recruitment of transGolgi membranes associated with Rab9 to damaged mitochondria through S179 phosphorylation of Rab9 by Ulk1 and S616 phosphorylation of Drp1 by Rip1. Knockin of Rab9 (S179A) abolished mitophagy and exacerbated the injury in response to myocardial ischemia, without affecting conventional autophagy. Mitophagy mediated through the Ulk1/Rab9/Rip1/Drp1 pathway protected the heart against ischemia by maintaining healthy mitochondria

Differential Requirement for Utrophin in the Induced Pluripotent Stem Cell Correction of Muscle versus Fat in Muscular Dystrophy Mice

Duchenne muscular dystrophy (DMD) is an incurable degenerative muscle disorder. We injected WT mouse induced pluripotent stem cells (iPSCs) into mdx and mdx∶utrophin mutant blastocysts, which are predisposed to develop DMD with an increasing degree of severity (mdx <<< mdx∶utrophin). In mdx chimeras, iPSC-dystrophin was supplied to the muscle sarcolemma to effect corrections at morphological and functional levels. Dystrobrevin was observed in dystrophin-positive and, at a lesser extent, utrophin-positive areas. In the mdx∶utrophin mutant chimeras, although iPSC-dystrophin was also supplied to the muscle sarcolemma, mice still displayed poor skeletal muscle histopathology, and negligible levels of dystrobrevin in dystrophin- and utrophin-negative areas. Not only dystrophin-expressing tissues are affected by iPSCs. Mdx and mdx∶utrophin mice have reduced fat/body weight ratio, but iPSC injection normalized this parameter in both mdx and mdx∶utrophin chimeras, despite the fact that utrophin was compromised in the mdx∶utrophin chimeric fat. The results suggest that the presence of utrophin is required for the iPSC-corrections in skeletal muscle. Furthermore, the results highlight a potential (utrophin-independent) non-cell autonomous role for iPSC-dystrophin in the corrections of non-muscle tissue like fat, which is intimately related to the muscle

Assessing Walking Ability in People with HTLV-1-Associated Myelopathy Using the 10 Meter Timed Walk and the 6 Minute Walk Test

Five to ten million persons, are infected by HTLV-1 of which 3% will develop HTLV-1-associated myelopathy (HAM) a chronic, disabling inflammation of the spinal cord. Walking, a fundamental, complex, multi-functional task is demanding of multiple body systems. Restricted walking ability compromises activity and participation levels in people with HAM (pwHAM). Therapy aims to improve mobility but validated measures are required to assess change.Prospective observational study.To explore walking capacity in pwHAM, walking endurance using the 6 minute walk (6MW), and gait speed, using the timed 10m walk (10mTW).Out-patient setting in an inner London Teaching hospital.Prospective documentation of 10mTW and 6MW distance; walking aid usage and pain scores measured twice, a median of 18 months apart.Data analysis was completed for twenty-six pwHAM, (8♂; 18♀; median age: 57.8 years; median disease duration: 8 years). Median time at baseline to: complete 10m was 17.5 seconds, versus 21.4 seconds at follow up; 23% completed the 6MW compared to 42% at follow up and a median distance of 55m was covered compared to 71m at follow up. Using the 10mTW velocity to predict the 6MW distance, overestimated the distance walked in 6 minutes (p<0.01). Functional decline over time was captured using the functional ambulation categories.The 10mTW velocity underestimated the degree of disability. Gait speed usefully predicts functional domains, shows direction of functional change and comparison with published healthy age matched controls show that these patients have significantly slower gait speeds. The measured differences over 18 months were sufficient to reliably detect change and therefore these assessments can be useful to detect improvement or deterioration within broader disability grades. Walking capacity in pwHAM should be measured using the 10mTW for gait speed and the 6MW for endurance

Muscle activation during gait in children with Duchenne muscular dystrophy

The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD). Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analysed quantitatively and qualitatively. The overall muscle activity in the children with DMD was significantly different from that of the control group. Percentage activation amplitudes of RF, HS and TA were greater throughout the gait cycle in the children with DMD and the timing of GAS activity differed from the control children. Significantly greater muscle coactivation was found in the children with DMD. There were no significant differences between sides. Since the motor command is normal in DMD, the hyper-activity and co-contractions likely compensate for gait instability and muscle weakness, however may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapies may improve stability and thus the pattern of muscle activity

Targeted Inactivation of Cerberus Like-2 Leads to Left Ventricular Cardiac Hyperplasia and Systolic Dysfunction in the Mouse

Previous analysis of the Cerberus like 2 knockout (Cerl2(-/-)) mouse revealed a significant mortality during the first day after birth, mostly due to cardiac defects apparently associated with randomization of the left-right axis. We have however, identified Cerl2-associated cardiac defects, particularly a large increase in the left ventricular myocardial wall in neonates that cannot be explained by laterality abnormalities. Therefore, in order to access the endogenous role of Cerl2 in cardiogenesis, we analyzed the embryonic and neonatal hearts of Cerl2 null mutants that did not display a laterality phenotype. Neonatal mutants obtained from the compound mouse line Cer2(-/-)Fundacao para a Ciencia e Tecnologia (FCT); IBB/CBME [PEst-OE/EQB/LA0023/2011]; FCT [SFRH/BD/62081/2009]info:eu-repo/semantics/publishedVersio