Comparative Analysis of Learning Effect for Students who Experienced both Lecture-based Learning and Problem-based Learning in a Complete Denture Course

PURPOSE

The purpose of this study was to analyze the difference in educational effect on students who experienced both lecture-based learning (LBL) and problem-based learning (PBL) in a complete denture course. The analysis focused on differences between the two methods concerning self study, ability to understand clinical inference, and appraisal of class contents and tutors.

METHODS

In the complete denture preclinical course, the class of 2003 received LBL in 3rd grade and PBL in 4th grade. PBL was planned to present five cases in five consecutive classes. Group discussion was carried out for each case, and a summary was required to be produced two times as a group, two times as an individual report and one time by group presentation. A questionnaire regarding the educational effect of LBL and PBL and assessment of tutors was administered. Factor analysis was carried out to classify the questionnaire items and each item was analyzed between LBL and PBL (Paired-t test).

RESULTS

Factor analysis revealed that the questionnaire items could be classified into four components. Comparing lecture type and PBL: "study attitude" (4 out of 7 items), "clinical inference ability" (all items), "class contents" (5 out of 7 items) and "tutor appraisal" (2 out of 5 items) showed significant assessment with PBL. Eighteen of 27 items (66.6%) indicated the significant usefulness of PBL.

CONCLUSION

PBL improves the educational effect of self study and clinical inference ability, in comparison with LBL. However, since students are passive about taking the same system class repeatedly, a strategy to improve their attitude needs to be considered.

Collagen type I-induced Smad-interacting protein 1 expression downregulates E-cadherin in pancreatic cancer

Pancreatic cancer is a devastating disease with poor prognosis. Production of large quantities of extracellular matrix and early metastasis are characteristics of this disease. One important step in the development of various cancers is the loss of E-cadherin gene expression or inactivation of E-cadherin mediated cell-cell adhesion. It has been shown that collagen type I promotes downregulation of E-cadherin expression, which correlates with enhanced cell migration and invasiveness. In this context, we elucidated the role of Smad-interacting protein 1 (SIP1), which has been discussed as a negative regulator of E-cadherin gene expression. We demonstrate that SIP1 upregulation shows an inverse relationship with E-cadherin in advanced pancreatic tumour stages. In Panc-1 cells, SIP1 expression can be induced by exposure to collagen type I in a src-dependent manner. In addition, overexpression of SIP1 reduces E-cadherin mRNA and protein levels. Taken together, these results suggest that SIP1 is involved in the progression of pancreatic cancer and plays a role in mediating signal transduction from collagen type I to downregulate E-cadherin expression.

Laser-mediated microdissection of paraffin sections from Xenopus embryos allows detection of tissue-specific expressed mRNAs

One of the key end points for understanding the molecular basis of embryogenesis is the analysis of spatiotemporal patterns of gene expression. Methodical limitations due to low mRNA levels often prevent a tissue-specific resolution. In this study, we developed an improved laser microdissection technique and RT-PCR that allows marker gene detection in small tissue areas from sections of formalin-fixed paraffin-embedded Xenopus embryos. Tissue pieces were isolated by laser microbeam microdissection and captured by laser pressure catapulting. Neither laser treatment nor conventional histological or immunochemical staining impaired subsequent RNA analysis. Transcripts of tissue-specific marker genes such as endodermin (endoderm), epidermal cytokeratin (epidermal ectoderm), N-CAM (neural tube), myoD (somites), and sonic hedgehog (floor plate) were amplified by nested RT-PCR analysis from small areas of single sections.

Molecular characterization and expression pattern of XY body-associated protein XY40 of the rat

The XY body is a structure formed by the partially synapsed chromosomes X and Y that is located at the nuclear periphery of mammalian pachytene spermatocytes. In contrast to the autosomal bivalents of the same nucleus, the XY body is characterized by its differential chromatin condensation and transcriptional inactivity. In order to shed some light on the biological significance of these differences we have been characterizing XY body-associated proteins. We present here the cDNA sequence and expression pattern of XY40, a protein that is associated with the axial elements of the XY body. RNA blot analysis revealed that during spermatogenesis the transcript that encodes protein XY40 was highly enriched in pachytene spermatocytes. This transcript was also detectable in brain and, to a lesser extent, in liver and kidney. Although the signal in brain was as strong as in spermatocytes, protein XY40 could be detected only in the latter. The nucleic acid sequence reveals that XY40 is a novel protein with a few similarities to already known nucleotide sequences. Among these similarities the most interesting is a box that is shared by the 3' untranslated region of XY40 and the 5' untranslated region of Munc-18c, a member of a protein family involved in synaptic vesicle exocytosis. Since the transcripts of both XY40 and Munc18-c show a similar expression pattern, it is tempting to speculate that this common sequence is involved in translation regulation.