Longitudinal PBL in Undergraduate Medical Education Develops Lifelong-Learning Habits and Clinical Competencies in Social Aspects.

Problem-based learning (PBL) is popular in medical education in Japan. We wished to understand the influence of PBL on the clinical competence of medical residents, using self-assessment and observer assessment. Tokyo Women's Medical University (TWMU) implemented PBL longitudinally (long-time) for four years, and on this basis we analyzed whether long-time PBL education is useful for clinical work.

Foregut endoderm is specified early in avian development through signal(s) emanating from Hensen's node or its derivatives.

In this study, the initial specification of foregut endoderm in the chick embryo was analyzed. A fate map constructed for the area pellucida endoderm at definitive streak-stage showed centrally-located presumptive cells of foregut-derived organs around Hensen's node. Intracoelomic cultivation of the area pellucida endoderm at this stage combined with somatic mesoderm resulted in the differentiation predominantly into intestinal epithelium, suggesting that this endoderm may not yet be regionally specified.

Facilitation of problem finding among first year medical school students undergoing problem-based learning.

Background: Adaptation to problem-based learning (PBL) is a difficult process for high school graduates who are not used to self-directed learning, especially in the freshmen year of medical school. The difficulty includes finding problems from a given case.

Purpose: Evaluate the effect of an intervention to facilitate case-based problem finding among medical school freshmen undergoing a PBL tutorial.

Pre-gut endoderm of chick embryos is regionalized by 1.5 days of development.

In this study, we set out to test the ability of endoderm from 1.5-day-old chick embryos (just before digestive tube formation) to develop region-specific characteristics when cultured heterotopically. Various parts of the 1.

Chronological changes in the sucrase antigen-inducing activity and development of the regional identity in the intestinal mesoderm of the chick embryo.

Developmental changes in mesodermal activity to induce intestine-like differentiation expressing sucrase antigen in the endoderm and changes in endodermal reactivity to such an activity in the digestive tract of the chick embryo were analyzed. Digestive-tract endoderms of embryos at 3 days of incubation were highly responsive to the inductive effect of the 5 day duodenal mesenchyme, with the stomach endoderm lying nearest to the intestine having the highest reactivity. Endodermal reactivity decreased with increasing age.

Fate mapping study of the endoderm of the 1.5-day-old chick embryo.

Various portions of the endoderm between the levels of the first and the 10th somite of 1.5-day-old chick embryos were marked by local application of the vital dye Dil, and the fate of marked cells was analyzed after cultivation of the embryos for 2 days in vitro.The presumptive area of digestive tract ranging from the posterior pharynx to the jejunum was found to extend bilaterally from the midline of the 1.

Fate mapping study of the splanchnopleural mesoderm of the 1.5-day-old chick embryo.

Various portions of the splanchnopleural mesoderm lateral to the somites of 1.5-day chick embryos were marked in ovo by local injection of Dil, and the distribution of the labelled cells in the digestive-tract mesoderm formed after 3 days' reincubation was analysed. The presumptive area of the digestive organs was confined to bands of splanchnic mesoderm lying lateral to the somites, on both sides, with a width two or three times that between the midline of the embryo and the lateral edge of the somite.

Regional difference in the responsiveness to the inductive influence of the gizzard mesenchyme among the endoderms of various small intestinal segments of the chick embryo.

The differentiation of the endoderms of duodenal, jejunal and ileal segments of the small intestine of 6 day old chick embryos cultured in recombination with the gizzard mesenchyme of 6 day chick embryos was examined. Only the duodenal endoderm differentiated in a mesenchyme-dependent fashion into gizzard-like mucous epithelium forming tubular glands that expressed no sucrase-antigen, while jejunal and ileal endoderms tended to become the sucrase-antigen-positive epithelium most likely according to their developmental fates. The analysis on the differentiation of the duodenal and gizzard endoderms in the presence of various digestive-tract mesenchymes confirmed that the duodenal endoderm had the tendency to differentiate into intestine-type and was different from the gizzard endoderm, which showed the differentiation tendency into gizzard-type.

Appearance of brush-border antigens and sucrase in the allantoic endoderm cultured in recombination with digestive-tract mesenchymes.

Allantoic endoderm of 3.5-day chick embryos was cultured in recombination with digestive-tract mesenchymes of 6-day chick embryos, and the differentiation of the endoderm was studied, with special attention being given to the appearance of brush-border (BB) antigens and sucrase. Irrespective of the origin of the associated digestive-tract mesenchymes, the allantoic endoderm differentiated into a columnar epithelium, expressing BB antigens and sucrase, and also into a BB antigen-negative pseudostratified or stratified epithelium of cuboidal or columnar cells with PAS or alcian blue staining in the apical portion or a BB antigen-negative stratified squamous epithelium.