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Atrial Cavity (atrial + cavity)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Cor Triatriatum Sinister with and without Left Ventricular Inflow Obstruction: Visualization of the Entire Supravalvular Membrane by Real-time Three-dimensional Echocardiography.

CONGENITAL HEART DISEASE, Issue 6 2006
Impact on Clinical Management of Individual Patient
ABSTRACT We present 4 cases of cor triatriatum in whom the diagnosis was correctly made by 2-dimensional transthoracic echocardiography, which showed the supravalvular left atrial membrane that divides the left atrium into 2 chambers. The pulmonary veins were connected normally to the proximal left atrial chamber and the left atrial appendage was connected to the distal left atrial chamber. In 1 patient there was evidence of severe pulmonary venous obstruction to the mitral valve by Doppler examination, while in the other three, there was no venous obstruction. Patients were then examined by real-time 3-dimensional echocardiography (RT3DE, using ×4 matrix array transducer connected to Sonos 7500 echocardiographic system Phillips, Andover, Mass, USA). This showed the exact morphology of the membrane and led to cancellation of planed surgical intervention in 1 case in which the membrane was only a broad band crossing the left atrial cavity. In addition to delineating the exact morphology of the intracavitary anomaly, this novel echocardiographic imaging modality should be an additive tool to better understand the natural history of these nonobstructive left atrial membranes via longitudinal follow-up of these patients. [source]

Acinetobacter Endocarditis Presenting as a Large Right Atrial Mass: An Atypical Presentation

ECHOCARDIOGRAPHY, Issue 4 2010
Sherrita Bhagan-Bruno M.D.
This paper discusses a 26-year-old woman with end-stage renal disease on hemodialysis and Acinetobacter calcoaceticus-baumannii complex endocarditis. The patient had an indwelling right internal jugular catheter that was probably the nidus of infection. Transthoracic echocardiogram revealed an atypical presentation of the endocarditis as a large intracardiac mass, measuring in centimeters and occupying more than 50% of the right atrial cavity. The mass was attached to the lateral wall of the right atrium without valvular involvement. The patient was treated with prompt removal of the indwelling catheter, intravenous antibiotics, and surgical resection of the mass with an uneventful recovery. A literature search for cases of "Acinetobacter endocarditis" reveals this as the first case reported of Acinetobacter endocarditis presenting in this manner. (Echocardiography 2010;27:E39-E42) [source]

The pre-radial history of echinoderms

GEOLOGICAL JOURNAL, Issue 3 2005
Andrew B. Smith
Abstract Gene sequence data now identify a robust phylogeny of deuterostomes and provide a framework within which the evolution of echinoderms can be interpreted. The topology of the molecular tree makes a number of important predictions about the morphological characters of the earliest echinoderm at its split from hemichordates: it possessed gill slits (but not a notochord), had a bilaterally symmetrical body plan in the adult and, less certainly, underwent torsion during development. Carpoids, a highly contentious group of extinct deuterostomes with a plated calcite skeleton that have variously been interpreted as stem- and crown-group chordates, stem-group echinoderms or stem- and crown-group echinoderms, display many of these basal characters and provide critical evidence for how the latest common ancestor of hemichordates and echinoderms was transformed into a pentaradiate crown-group echinoderm. Cinctans have a large atrial opening in addition to mouth and anus, and are interpreted as pharyngeal basket feeders. The paired grooves associated with the mouth indicate the presence of a hydrovascular system, but not necessarily one built along the echinoderm plan (that is, derived from just the left hydrocoel). Stylophorans have a bilateral body plan that is externally masked by torsion and possess gills, either unpaired and external, or paired and internal, opening into an atrial cavity. Their bilateral appendage is a locomotory organ, not an ambulacrum, and there is no evidence that stylophorans ever possessed a well-developed hydrovascular system homologous to the water vascular system of echinoderms and the tentacles of pterobranch hemichordates. Solutes are the most crownward, having a true echinodermal ambulacral system with a single hydropore and no pharyngeal gill openings. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Ultrastructure and embryonic development of a syconoid calcareous sponge

INVERTEBRATE BIOLOGY, Issue 3 2006
Dafne I. Eerkes-Medrano
Abstract. Recent molecular data suggest that the Porifera is paraphyletic (Calcarea+Silicea) and that the Calcarea is more closely related to the Metazoa than to other sponge groups, thereby implying that a sponge-like animal gave rise to other metazoans. One ramification of these data is that calcareous sponges could provide clues as to what features are shared among this ancestral metazoan and higher animals. Recent studies describing detailed morphology in the Calcarea are lacking. We have used a combination of microscopy techniques to study the fine structure of Syconcoactum Urban 1905, a cosmopolitan calcareous sponge. The sponge has a distinct polarity, consisting of a single tube with an apically opening osculum. Finger-like chambers, several hundred micrometers in length, form the sides of the tube. The inner and outer layers of the chamber wall are formed by epithelia characterized by apical,basal polarity and occluding junctions between cells. The outer layer,the pinacoderm,and atrial cavity are lined by plate-like cells (pinacocytes), and the inner choanoderm is lined by a continuous sheet of choanocytes. Incurrent openings of the sponge are formed by porocytes, tubular cells that join the pinacoderm to the choanoderm. Between these two layers lies a collagenous mesohyl that houses sclerocytes, spicules, amoeboid cells, and a progression of embryonic stages. The morphology of choanocytes and porocytes is plastic. Ostia were closed in sponges that were vigorously shaken and in sponges left in still water for over 30 min. Choanocytes, and in particular collar microvilli, varied in size and shape, depending on their location in the choanocyte chamber. Although some of the odd shapes of choanocytes and their collars can be explained by the development of large embryos first beneath and later on top of the choanocytes, the presence of many fused collar microvilli on choanocytes may reflect peculiarities of the hydrodynamics in large syconoid choanocyte chambers. The unusual formation of a hollow blastula larva and its inversion through the choanocyte epithelium are suggestive of epithelial rather than mesenchymal cell movements. These details illustrate that calcareous sponges have characteristics that allow comparison with other metazoans,one of the reasons they have long been the focus of studies of evolution and development. [source]