Anatomical Characterization (anatomical + characterization)

Distribution by Scientific Domains

Selected Abstracts

ECHO ROUNDS: Percutaneous Balloon Valvuloplasty for Pulmonic Stenosis: The Role of Multimodality Imaging

Davinder S. Jassal M.D., F.R.C.P.C.
Pulmonic valvular stenosis represents the most frequent cause of right ventricular outflow obstruction. Transthoracic echocardiography is the imaging modality of choice in the diagnosis, evaluation and longitudinal follow-up of individuals with pulmonic stenosis (PS). Although valvular PS is usually diagnosed by two-dimensional imaging, Doppler echocardiography allows for the quantification of severity of the valvular lesion. In patients with limited acoustic windows, computed tomography and cardiac magnetic resonance imaging may provide complementary anatomical characterization of the pulmonic annulus and valve prior to percutaneous balloon valvuloplasty. [source]

Phenotype of V2-derived interneurons and their relationship to the axon guidance molecule EphA4 in the developing mouse spinal cord

Line Lundfald
Abstract The ventral spinal cord consists of interneuron groups arising from distinct, genetically defined, progenitor domains along the dorsoventral axis. Many of these interneuron groups settle in the ventral spinal cord which, in mammals, contains the central pattern generator for locomotion. In order to better understand the locomotor networks, we have used different transgenic mice for anatomical characterization of one of these interneuron groups, called V2 interneurons. Neurons in this group are either V2a interneurons marked by the postmitotic expression of the transcription factor Chx10, or V2b interneurons which express the transcription factors Gata2 and Gata3. We found that all V2a and most V2b interneurons were ipsilaterally projecting in embryos as well as in newborns. V2a interneurons were for the most part glutamatergic while V2b interneurons were mainly GABAergic or glycinergic. Furthermore, we demonstrated that a large proportion of V2 interneurons expressed the axon guidance molecule EphA4, a molecule previously shown to be important for correct organization of locomotor networks. We also showed that V2 interneurons and motor neurons alone did not account for all EphA4-expressing neurons in the spinal cord. Together, these findings enable a better interpretation of neural networks underlying locomotion, and open up the search for as yet unknown components of the mammalian central pattern generator. [source]

Three-Dimensional Anatomy of the Left Atrium by Magnetic Resonance Angiography: Implications for Catheter Ablation for Atrial Fibrillation

Background: Pulmonary vein isolation (PVI) has become one of the primary treatments for symptomatic drug-refractory atrial fibrillation (AF). During this procedure, delivery of ablation lesions to certain regions of the left atrium can be technically challenging. Among the most challenging regions are the ridges separating the left pulmonary veins (LPV) from the left atrial appendage (LAA), and the right middle pulmonary vein (RMPV) from the right superior (RSPV) and right inferior (RIPV) pulmonary veins. A detailed anatomical characterization of these regions has not been previously reported. Methods: Magnetic resonance angiography (MRA) was performed in patients prior to undergoing PVI. Fifty consecutive patients with a RMPV identified by MRA were included in this study. Ridges associated with the left pulmonary veins were examined in an additional 30 patients who did not have a RMPV. Endoluminal views were reconstructed from the gadolinium-enhanced, breath-hold three-dimensional MRA data sets. Measurements were performed using electronic calipers. Results: The width of the ridge separating the LPV from the LAA was found to be 3.7 1.1 mm at its narrowest point. The segment of this ridge with a width of 5 mm or less was 16.6 6.4 mm long. The width of the ridges separating the RMPV from the RSPV and the RIPV was found to be 3.0 1.5 mm and 3.1 1.8 mm, respectively. There were no significant differences between LPV ridges for patients with versus without a RMPV. Conclusion: The width of the ridges of atrial tissue separating LPV from the LAA and the RMPV from its neighboring veins may explain the technical challenge in obtaining stable catheter positions in these areas. A detailed assessment of the anatomy of these regions may improve the safety and efficacy of catheter ablation at these sites. [source]

Bladder exstrophy-epispadias complex

Michael Ludwig
Abstract The bladder exstrophy-epispadias complex (BEEC) represents an anterior midline defect with variable expression comprising a spectrum of anomalies involving the abdominal wall, pelvis, urinary tract, genitalia, and occasionally the spine and anus. The vast majority of BEEC cases are classified as non-syndromic and the etiology of this malformation is still unknown. This review presents the current state of knowledge on this multifactorial disorder, including historical retrospect, phenotypic and anatomical characterization, epidemiology, proposed developmental mechanisms, existing animal models, and implicated genetic and environmental components. These published lines of evidence argue strongly that BEEC occurs as a result of strong genetic predisposition that is yet to be deciphered. Birth Defects Research (Part A), 2009. 2009 Wiley-Liss, Inc. [source]