Xwnt-8 and lithium can act upon either dorsal mesodermal or neurectodermal cells to cause a loss of forebrain in Xenopus embryos

When Xenopus gastrulae are made to misexpress Xwnt-8, or are exposed to lithium ions, they develop with a loss of anterior structures. In the current study, we have characterized the neural defects produced by either Xwnt-8 or lithium and have examined potential cellular mechanisms underlying this anterior truncation. We find that the primary defect in embryos exposed to lithium at successively earlier stages during gastrulation is a progressive rostral to caudal deletion of the forebrain, while hindbrain and spinal regions of the CNS remain intact. Misexpression of Xwnt-8 during gastrulation produces an identical loss of forebrain. Our results demonstrate that lithium and Wnts can act upon either prospective neural ectodermal cells, or upon dorsal mesodermal cells, to cause a loss of anterior pattern. Specifically, ectodermal cells isolated from lithium- or Wnt-exposed embryos are unable to form anterior neural tissue in response to inductive signals from normal dorsal mesoderm. In addition, although dorsal mesodermal cells from lithium- or Wnt-exposed embryos are specified properly, and produce normal levels of the anterior neural inducing molecules noggin and chordin, they show a greatly reduced capacity to induce anterior neural tissue in conjugated ectoderm. Taken together, our results are consistent with a model in which Wnt- or lithium-mediated signals can induce either mesodermal or ectodermal cells to produce a dominant posteriorizing morphogen which respecifies anterior neural tissue as posterior

Anomalies of the Extensor Pollicis Longus and Extensor Indicis Muscles in Two Cadaveric Cases

This find is registered at Portable Antiquities of the Netherlands with number PAN-0007182

A Guide to Competencies, Educational Goals, and Learning Objectives for Teaching Human Embryology in an Undergraduate Medical Education Setting

With the rapidly changing course of medical education and ever-increasing time restrictions on basic biomedical science instruction, most educators have one question in common—what is the most relevant information for the next generation of physicians? The Liaison Committee for Medical Education (LCME) and the Commission on Osteopathic College Accreditation (COCA) support a list of learning objectives for medical students defined by faculty prior to any educational activities, regardless of pedagogy. The question remains—what ensures competency for medical students in a given subject area upon completion of the course? To accomplish the task to ensure competency in human clinical embryology, a 6-month interactive online collaboration was formed. The outcome is a set of competencies in human embryology that should be required of all medical students, with the goals and learning objectives required to achieve these competencies

A Guide to Competencies, Educational Goals, and Learning Objectives for Teaching Human Embryology in an Undergraduate Medical Education Setting

With the rapidly changing course of medical education and ever-increasing time restrictions on basic biomedical science instruction, most educators have one question in common—what is the most relevant information for the next generation of physicians? The Liaison Committee for Medical Education (LCME) and the Commission on Osteopathic College Accreditation (COCA) support a list of learning objectives for medical students defined by faculty prior to any educational activities, regardless of pedagogy. The question remains—what ensures competency for medical students in a given subject area upon completion of the course? To accomplish the task to ensure competency in human clinical embryology, a 6-month interactive online collaboration was formed. The outcome is a set of competencies in human embryology that should be required of all medical students, with the goals and learning objectives required to achieve these competencies

Comparison of MRI and CT for detection of acute intracerebral hemorrhage.

CONTEXT: Noncontrast computed tomography (CT) is the standard brain imaging study for the initial evaluation of patients with acute stroke symptoms. Multimodal magnetic resonance imaging (MRI) has been proposed as an alternative to CT in the emergency stroke setting. However, the accuracy of MRI relative to CT for the detection of hyperacute intracerebral hemorrhage has not been demonstrated. OBJECTIVE: To compare the accuracy of MRI and CT for detection of acute intracerebral hemorrhage in patients presenting with acute focal stroke symptoms. DESIGN, SETTING, AND PATIENTS: A prospective, multicenter study was performed at 2 stroke centers (UCLA Medical Center and Suburban Hospital, Bethesda, Md), between October 2000 and February 2003. Patients presenting with focal stroke symptoms within 6 hours of onset underwent brain MRI followed by noncontrast CT. MAIN OUTCOME MEASURES: Acute intracerebral hemorrhage and any intracerebral hemorrhage diagnosed on gradient recalled echo (GRE) MRI and CT scans by a consensus of 4 blinded readers. RESULTS: The study was stopped early, after 200 patients were enrolled, when it became apparent at the time of an unplanned interim analysis that MRI was detecting cases of hemorrhagic transformation not detected by CT. For the diagnosis of any hemorrhage, MRI was positive in 71 patients with CT positive in 29 (P CONCLUSION: MRI may be as accurate as CT for the detection of acute hemorrhage in patients presenting with acute focal stroke symptoms and is more accurate than CT for the detection of chronic intracerebral hemorrhage