Molecular evidence of anteroposterior patterning in adult echinoderms.

The origin of the pentaradial body plan of echinoderms from a bilateral ancestor is one of the most enduring zoological puzzles1,2. Because echinoderms are defined by morphological novelty, even the most basic axial comparisons with their bilaterian relatives are problematic. To revisit this classical question, we used conserved anteroposterior axial molecular markers to determine whether the highly derived adult body plan of echinoderms masks underlying patterning similarities with other deuterostomes. We investigated the expression of a suite of conserved transcription factors with well-established roles in the establishment of anteroposterior polarity in deuterostomes3-5 and other bilaterians6-8 using RNA tomography and in situ hybridization in the sea star Patiria miniata. The relative spatial expression of these markers in P. miniata ambulacral ectoderm shows similarity with other deuterostomes, with the midline of each ray representing the most anterior territory and the most lateral parts exhibiting a more posterior identity. Strikingly, there is no ectodermal territory in the sea star that expresses the characteristic bilaterian trunk genetic patterning programme. This finding suggests that from the perspective of ectoderm patterning, echinoderms are mostly head-like animals and provides a developmental rationale for the re-evaluation of the events that led to the evolution of the derived adult body plan of echinoderms.

Use of a cantilevered acrylic splint in the autogenous transplantation of a third molar: report of case.

A case report offers details of autogenous transplantation of an unerupted third molar to the first molar position. Stabilization of the transplant required a cantilevered acrylic resin splint--because of the absence of the second molar--as a terminal splint abutment. Guidelines for the proper procedures and criteria for case selection are reviewed.

Analysis of nurse-doctorates; data collected for the International Directory of Nurses with Doctoral Degrees.

In an American Nurses' Foundation survey of the 1973 population of nurses with doctoral degrees (N = 1,020) general trends in doctoral education of nurses were elicited. Specific unique characteristics were highlighted, including: a continuing trend for nurses to earn the Ph.D. rather than the Ed.D., a divergence between field of doctoral study and the current field of research interest, and a slight number of these qualified nurses actually participating in research of any kind. The majority of subjects were single; most were employed in a university or college where they held either full or associate professorships; most considered themselves still to be in the field of nursing, although their doctoral studies frequently took them out of the discipline; their work responsibilities were heavily loaded with administrative duties. As compared with the holders of doctoral degrees in other fields, nurses earned their degrees later, but took no longer to complete them. While universities in the Mid-Atlantic states were the largest producers of nurse-doctorates, universities in the Midwest were found to be the most frequent employers. Questions regarding the future direction of nurse-doctorates were raised.