Claudio Cortes

Late results of a prospective randomised study comparing forceful dilatation and oesophagomyotomy in patients with achalasia.

Late results in 81 patients with achalasia treated in a prospective randomised study comparing forceful pneumatic dilatation with the Mosher bag and surgical anterior oesophagomyotomy by abdominal route, are reported. There were no deaths from either of the treatments. Two patients (5.6%) had a perforation of the abdominal oesophagus after pneumatic dilatation and were excluded from late follow up. In patients having surgery at radiological evaluation there was gullet diameter significantly increased at the oesophagogastric junction and decreased at the middle third of the oesophagus. One patient was lost from follow up and one died of an oesophageal carcinoma, leaving 95% of excellent results at the late follow up (median 62 months). Resting gastro-oesophageal sphincter pressure decreased significantly to approximately 10 mmHg; this was maintained five years after surgery. By contrast, in patients having pneumatic dilatation, there were good results in only 65% (follow up median 58 months), with 30% failures. One patient was lost from follow up and one developed oesophageal carcinoma. Measurement of resting gastro-oesophageal sphincter pressure after dilatation was highly predictive of the outcome. The study shows that surgical treatment offers a better final clinical result than pneumatic dilatation with the Mosher bag.

Short-Rib Polydactyly and Jeune Syndromes Are Caused by Mutations in WDR60

Short-rib polydactyly syndromes (SRPS I-V) are a group of lethal congenital disorders characterized by shortening of the ribs and long bones, polydactyly, and a range of extraskeletal phenotypes. A number of other disorders in this grouping, including Jeune and Ellis-van Creveld syndromes, have an overlapping but generally milder phenotype. Collectively, these short-rib dysplasias (with or without polydactyly) share a common underlying defect in primary cilium function and form a subset of the ciliopathy disease spectrum. By using whole-exome capture and massive parallel sequencing of DNA from an affected Australian individual with SRPS type III, we detected two novel heterozygous mutations in WDR60, a relatively uncharacterized gene. These mutations segregated appropriately in the unaffected parents and another affected family member, confirming compound heterozygosity, and both were predicted to have a damaging effect on the protein. Analysis of an additional 54 skeletal ciliopathy exomes identified compound heterozygous mutations in WDR60 in a Spanish individual with Jeune syndrome of relatively mild presentation. Of note, these two families share one novel WDR60 missense mutation, although haplotype analysis suggested no shared ancestry. We further show that WDR60 localizes at the base of the primary cilium in wild-type human chondrocytes, and analysis of fibroblasts from affected individuals revealed a defect in ciliogenesis and aberrant accumulation of the GLI2 transcription factor at the centrosome or basal body in the absence of an obvious axoneme. These findings show that WDR60 mutations can cause skeletal ciliopathies and suggest a role for WDR60 in ciliogenesis.

Recognition of an immunogenetically selected Trypanosoma cruzi antigen by seropositive chagasic human sera

If the H-2 congenic mouse strains A.SW (H-2n) and A.CA (H-2f), are infected with Trypanosoma cruzi, a 45 kDa protein (Tc45), present in cultured epimastigotes and blood trypomastigotes, is recognized only by the A.SW strain sera. In order to explore the possibility that among seropositive humans the response to Tc45 is also highly variable, 81 chagasic human sera (as defined by the HemAve agglutination test, Polychaco S.A.I.C., Buenos Aires, Argentina) were tested in a direct (epimastigote antigenic complex directly bound to the solid phase) and indirect immunoradiometric assay (IRMA) (Tc45, from a partially purified preparation, bound to the solid phase, by means of a monoclonal antibody). Sixty nine of these sera reacted in both the direct and indirect assays, 11 were negative in both assays (these samples may correspond to false positives detected by the commercial agglutination test) and only one reacted with the antigenic complex but not with Tc45. Reactivity of the human sera with the epimastigote antigenic extract was relatively homogenous, while reactivity with Tc45 was extremely variable. No statistical correlation was determined between the two variables. Given the high variability of the human response to Tc45, ranging from negative to highly positive, together with the immunogenetic restriction previously described in the murine model, we speculate that human MHC may also modulate the response to this molecule.

Yeast-based assay identifies novel Shh/Gli target genes in vertebrate development

BackgroundThe increasing number of developmental events and molecular mechanisms associated with the Hedgehog (Hh) pathway from Drosophila to vertebrates, suggest that gene regulation is crucial for diverse cellular responses, including target genes not yet described. Although several high-throughput, genome-wide approaches have yielded information at the genomic, transcriptional and proteomic levels, the specificity of Gli binding sites related to direct target gene activation still remain elusive. This study aims to identify novel putative targets of Gli transcription factors through a protein-DNA binding assay using yeast, and validating a subset of targets both in-vitro and in-vivo. Testing in different Hh/Gli gain- and loss-of-function scenarios we here identified known (e.g., ptc1) and novel Hh-regulated genes in zebrafish embryos.ResultsThe combined yeast-based screening and MEME/MAST analysis were able to predict Gli transcription factor binding sites, and position mapping of these sequences upstream or in the first intron of promoters served to identify new putative target genes of Gli regulation. These candidates were validated by qPCR in combination with either the pharmacological Hh/Gli antagonist cyc or the agonist pur in Hh-responsive C3H10T1/2 cells. We also used small-hairpin RNAs against Gli proteins to evaluate targets and confirm specific Gli regulation their expression. Taking advantage of mutants that have been identified affecting different components of the Hh/Gli signaling system in the zebrafish model, we further analyzed specific novel candidates. Studying Hh function with pharmacological inhibition or activation complemented these genetic loss-of-function approaches. We provide evidence that in zebrafish embryos, Hh signaling regulates sfrp2, neo1, and c-myc expression in-vivo.ConclusionA recently described yeast-based screening allowed us to identify new Hh/Gli target genes, functionally important in different contexts of vertebrate embryonic development.

Unmasking the ciliopathies: craniofacial defects and the primary cilium

Over the past decade, the primary cilium has emerged as a pivotal sensory organelle that acts as a major signaling hub for a number of developmental signaling pathways. In that time, a vast number of proteins involved in trafficking and signaling have been linked to ciliary assembly and/or function, demonstrating the importance of this organelle during embryonic development. Given the central role of the primary cilium in regulating developmental signaling, it is not surprising that its dysfunction results in widespread defects in the embryo, leading to an expanding class of human congenital disorders known as ciliopathies. These disorders are individually rare and phenotypically variable, but together they affect virtually every vertebrate organ system. Features of ciliopathies that are often overlooked, but which are being reported with increasing frequency, are craniofacial abnormalities, ranging from subtle midline defects to full‐blown orofacial clefting. The challenge moving forward is to understand the primary mechanism of disease given the link between the primary cilium and a number of developmental signaling pathways (such as hedgehog, platelet‐derived growth factor, and WNT signaling) that are essential for craniofacial development. Here, we provide an overview of the diversity of craniofacial abnormalities present in the ciliopathy spectrum, and reveal those defects in common across multiple disorders. Further, we discuss the molecular defects and potential signaling perturbations underlying these anomalies. This provides insight into the mechanisms leading to ciliopathy phenotypes more generally and highlights the prevalence of widespread dysmorphologies resulting from cilia dysfunction. WIREs Dev Biol 2015, 4:637–653. doi: 10.1002/wdev.199

Evolutive Radiological Changes of the Esophagus in Patients with Achalasia Who Did Not Receive Treatment

PurposeThe radiological features of achalasia of the esophagus are well known and have been described. However, very little is known concerning the natural history of this disease. We aimed to determine the evolutive radiological changes of the esophagus in a group of patients with achalasia who had not previously undergone any treatment.MethodsWe undertook a prospective study of 14 patients with achalasia from a group of 205 patients. They included 9 women and 5 men who did not receive any treatment at the initial diagnosis. Two radiological parameters were evaluated: (a) the maximal internal diameter of the middle third of the thoracic esophagus in millimeters and (b) the internal diameter of the esophagogastric junction in millimeters.ResultsAt a mean follow-up of 5-years without any treatment, there was a significant increase in the diameter of the thoracic esophagus, with a rate of “dilatation” of 6.1 mm/year. In addition, there was a significant decrease of the internal diameter of the esophagogastric junction, with a rate of “stenosis” of 1 mm/year. The lower esophageal sphincter was hypertensive in all with an incomplete relaxation.ConclusionThese results suggest that there is a progressive deterioration in the radiological parameters of the esophagus in patients with achalasia not treated over a 5-year period of observation.

Application of continuum damage theory in metalforming processes

Abstract In this work a methodology is presented to simulate the evolution of the mechanical damage suffered by a material when it is submitted to large elastoplastic strains. The thermodynamic theory of the irreversible processes permits to derive a constitutive law of elastoplasticity coupled with damage. The incorporation of this law in the formulation of the principle of virtual works and the application of the finite element method make possible the calculation of the representative parameter of the mechanical damage. Finally, a contact algorithm based on a penalty method permits the application to metalforming processes. Some simple examples show the usefulness of this methodology.

Bezoar gástrico como complicación de banda gástrica en manejo de obesidad mórbida: Caso clínico

Laparoscopic adjustable gastric banding (LAGB) is used for the management of morbid obesity. Phytobezoars are rarely reported as a complication of this operation and are usually extracted by endoscopic means. We report a 48-year-old male subjected to a gastric banding, that consulted for progressive dysphagia, six months after the operation. A barium meal x-ray examination demonstrated the presence of a bezoar that was dissolved in one week using papain. A control barium meal confirmed the disappearance of the bezoar.

Epithelial Properties of the Second Heart Field

The vertebrate heart tube forms from epithelial progenitor cells in the early embryo and subsequently elongates by progressive addition of second heart field (SHF) progenitor cells from adjacent splanchnic mesoderm. Failure to maximally elongate the heart results in a spectrum of morphological defects affecting the cardiac poles, including outflow tract alignment and atrioventricular septal defects, among the most common congenital birth anomalies. SHF cells constitute an atypical apicobasally polarized epithelium with dynamic basal filopodia, located in the dorsal wall of the pericardial cavity. Recent studies have highlighted the importance of epithelial architecture and cell adhesion in the SHF, particularly for signaling events that control the progenitor cell niche during heart tube elongation. The 22q11.2 deletion syndrome gene Tbx1 regulates progenitor cell status through modulating cell shape and filopodial activity and is required for SHF contributions to both cardiac poles. Noncanonical Wnt signaling and planar cell polarity pathway genes control epithelial polarity in the dorsal pericardial wall, as progenitor cells differentiate in a transition zone at the arterial pole. Defects in these pathways lead to outflow tract shortening. Moreover, new biomechanical models of heart tube elongation have been proposed based on analysis of tissue-wide forces driving epithelial morphogenesis in the SHF, including regional cell intercalation, cell cohesion, and epithelial tension. Regulation of the epithelial properties of SHF cells is thus emerging as a key step during heart tube elongation, adding a new facet to our understanding of the mechanisms underlying both heart morphogenesis and congenital heart defects.

Tbx1 regulates extracellular matrix- and cell-cell interactions in the second heart field.

Tbx1, the major candidate gene for DiGeorge or 22q11.2 deletion syndrome, is required for efficient incorporation of cardiac progenitors (CPs) of the second heart field (SHF) into the heart. However, the mechanisms by which TBX1 regulates this process are still unclear. Here, we have used two independent models, mouse embryos and cultured cells, to define the role of TBX1 in establishing morphological and dynamic characteristics of SHF in the mouse. We found that loss of TBX1 impairs extra cellular matrix (ECM)-integrin-focal adhesion (FA) signaling in both models. Mosaic analysis in embryos showed that this function is non-cell autonomous and, in cultured cells, loss of TBX1 impairs cell migration and focal adhesions. Additionally, we found that ECM-mediated outside-in integrin signaling is disrupted upon loss of TBX1. Finally, we show that interfering with the ECM-integrin-FA axis between E8.5 and E9.5 in mouse embryos, corresponding to the time window within which TBX1 is required in the SHF, causes outflow tract dysmorphogenesis. Our results demonstrate that TBX1 is required to maintain the integrity of ECM-cell interactions in the SHF, and that this interaction is critical for cardiac outflow tract development. More broadly, our data identifies a novel TBX1 downstream pathway as an important player in SHF tissue architecture and cardiac morphogenesis.