12 research outputs found
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Hirschsprung’s Disease: A Rare Adult Diagnosis
Case Presentation: Approximately 94% of patients with Hirschsprung’s disease (HD) are diagnosed before the age of five. In our case, a young adult with years of constipation presented to the emergency department with significant abdominal distention. He was ultimately diagnosed with HD, which was identified using computed tomography (CT).Discussion: In HD, we find defects in gastric motility due to improper gut colonization. Without childhood recognition, HD often leads to chronic constipation and failure to thrive in adulthood. CT is a key step in identifying this rare adult diagnosis that should be considered in all patients with a history of chronic constipation
Alteration heterogeneities in peridotites exhumed on the southern wall of the Atlantis Massif (IODP Expedition 357)
Serpentinized and metasomatized peridotites intruded by gabbros and dolerites have been drilled on the southern wall of the Atlantis Massif (Mid-Atlantic Ridge, 30°N) during International Ocean Discovery Program (IODP) Expedition 357. They occur in seven holes from five sites making up an east-west trending, spreading-parallel profile that crosscuts this exhumed detachment footwall. Here we have taken advantage of this sampling to study heterogeneities of alteration at scales less than a kilometer. We combine textural and mineralogical observations made on 77 samples with in situ major and trace element analyses in primary and serpentine minerals to provide a conceptual model for the development of alteration heterogeneities at the Atlantis Massif. Textural sequences and mineralogical assemblages reveal a transition between an initial pervasive phase of serpentinization and subsequent serpentinization and metasomatism focused along localized pathways preferentially used by hydrothermal fluids. We propose that these localized pathways are interconnected and form 100 m- to 1 km-sized cells in the detachment footwall. This change in fluid pathway distribution is accompanied by variable trace element enrichments in the serpentine textures: deep, syn-serpentinization fluid-peridotite interactions are considered the source of Cu, Zn, As, and Sb enrichments, whereas U and Sr enrichments are interpreted as markers of later, shallower fluid-serpentinized peridotite interaction. Alteration of gabbros and dolerites emplaced in the peridotite at different lithospheric levels leads to the development of amphibole, chlorite and, or, talc-bearing textures as well as enrichments in LREE, Nb, Y, Th, Ta in the serpentine textures of the surrounding peridotites. Combining these observations, we propose a model that places the drill holes in a conceptual frame involving mafic intrusions in the peridotites and heterogeneities during progressive alteration and emplacement on the seafloor