Gastric bronchogenic cyst presenting as a submucosal mass: a case report

ABSTRACT: INTRODUCTION: Bronchogenic cysts are developmental anomalies of the primitive foregut which mostly occur in the lung. Gastric bronchogenic cysts are extremely rare; few cases have been reported in the literature and the diagnosis was often made following surgical resection. CASE PRESENTATION: A 40-year-old North African man was admitted to our hospital with a gastric submucosal mass. An endoscopic ultrasound revealed a unilocular cystic mass located in the muscular layer. Its content was echogenic suggestive of mucus. Magnetic resonance imaging confirmed the liquid nature of the cyst and showed a high ratio of proteins. Based on these observations, the diagnosis of bronchogenic cyst was confirmed. An endoscopic monitoring was decided rather than surgery because of the small size of the cyst and the absence of symptoms. CONCLUSION: Although gastric bronchogenic cysts are rare, they should be well known and considered in all differential diagnoses of gastric tumors. We report a new case of gastric bronchogenic cyst and highlight the contribution of morphological tests that currently allow a non-invasive diagnosis.     

Functional diversity of microboring Ostreobium algae isolated from corals

The filamentous chlorophyte Ostreobium sp. dominates shallow marine carbonate microboring communities, and is one of the major agents of reef bioerosion. While its large genetic diversity has emerged, its physiology remains little known, with unexplored relationship between genotypes and phenotypes (endolithic versus free-living growth forms). Here, we isolated nine strains affiliated to two lineages of Ostreobium (>8% sequence divergence of the plastid gene rbcL), one of which was assigned to the family Odoaceae, from the fast-growing coral host Pocillopora acuta Lamarck 1816. Free-living isolates maintained their bioerosive potential, colonizing pre-bleached coral carbonate skeletons. We compared phenotypes, highlighting shifts in pigment and fatty acid compositions, carbon to nitrogen ratios and stable isotope compositions (δ¹³C and δ¹⁵N). Our data show a pattern of higher chlorophyll b and lower arachidonic acid (20:4ω6) content in endolithic versus free-living Ostreobium. Photosynthetic carbon fixation and nitrate uptake, quantified via 8 h pulse-labeling with ¹³C-bicarbonate and ¹⁵N-nitrate, showed lower isotopic enrichment in endolithic compared to free-living filaments. Our results highlight the functional plasticity of Ostreobium phenotypes. The isotope tracer approach opens the way to further study the biogeochemical cycling and trophic ecology of these cryptic algae at coral holobiont and reef scales.     

Neuromuscular structure of the larva to early ancestrula stages of the cyclostome bryozoan Crisia eburnea

For the first time, the development of a cyclostome bryozoan has been studied with immunochemistry and confocal laser scanning microscopy, with emphasis on nerves and muscles. The larva is covered by multiciliated cells, which are latitudinally strongly elongated and show phalloidin-stained cell junctions. We hypothesize that these cells contract at metamorphosis and squeeze the apical invagination and the adhesive sac out. Ectodermal, longitudinal muscle cells extend from the cells of the inner, conical cuticularized part of the apical invagination to the lower part of the corona, around the adhesive sac pore. These muscles are retained in the ancestrula. Scattered monociliated nerve cells are interspersed between the coronal ciliary cells. An equatorial nerve in the larva disappears at metamorphosis. The central, conical part of the cuticle becomes the terminal membrane of the ancestrula, and the underlying ectodermal and mesodermal cell layers differentiate into the polypide bud, forming a deep narrow invagination, differentiating into vestibule–atrium, mouth ring and pharynx–stomach–rectum. Tentacles develop from the ring of cells around the mouth, and a small ganglion with four nerves innervating each of the tentacles develops at the anal side of the mouth. These new findings yield further support for previous homology statements of bryozoan larvae and development.     

Nucleotide sequence of the woodchuck hepatitis virus surface antigen mRNAs and the variability of three overlapping viral genes

A cDNA library was constructed from the liver of a woodchuck chronically infected with woodchuck hepatitis virus (WHV). A clone, pWS23, encompassing the entire surface and X genes of WHV was isolated. Comparison of the complete nucleotide (nt) sequence of pWS23 with those of genomic DNAs from two different WHV isolates showed that it contained a nearly full-length copy of the major mRNA encoding the viral surface antigen (5 mRNA). It was colinear with the WHV genome over 1858 nt and terminated 22 nt downstream from the variant polyadenylation signal within the core gene. Evidence for heterogeneity of the 5′ -terminal region of the S mRNA came from direct sequencing of the 5′ extremities of 20 cDNA inserts, similar to that of pWS23, isolated from a second cDNA library of the same woodchuck liver. In agreement with previous mapping studies of hepadnaviruses, two main initiation regions of S mRNA were localized 27–30 nt upstream and 22–49 nt downstream from the pre-S2 initiation codon. Further analysis of the amino acid sequences of the surface, polymerase and X genes of WHV showed a high conservation among three WHY isolates and a similar distribution of conserved and variable regions in woodchuck and human hepatitis B viruses.