Improving Thai students' understanding of concepts in protein purification by using Thai and English versions of a simulation program*.

To support student learning in biochemistry and related courses, a simulation program, the Protein Purification Program, offers an alternative multimedia-based tool. This program has now been translated to produce a Thai version. However, translation from the original into the Thai language is limited by the differences between the language characteristics of English and Thai.

The effect of the amelogenin fraction of enamel matrix proteins on fibroblast-mediated collagen matrix reorganization.

Enamel matrix proteins (EMP), extracted from developing porcine teeth, promote not only periodontal regeneration but also cutaneous wound healing presumably via the amelogenin fraction. Because it is unclear whether the effect of EMP can be ascribed to amelogenins, we compared EMP with recombinant amelogenin in the relaxed dermal equivalent (DE) in vitro model for early wound contraction. EMP and recombinant porcine amelogenin (rP172) at 1 mg/ml were incorporated into DEs composed of human dermal fibroblasts and a type I collagen matrix.

Involvement of protein kinase C in chitosan glutamate-mediated tight junction disruption.

Chitosan has been successfully used as an excipient for trans-epithelial drug delivery systems. It is known to transiently open intercellular tight junctions thus increasing the permeability of an epithelium. In order to investigate the possible role of protein kinases in trans-epithelial delivery, changes in trans-epithelial electrical resistance ('TEER') of epithelial (Caco-2) cell monolayers were assessed in response to chitosan glutamate treatment, in the presence and absence of specific protein kinase inhibitors.

Problem-based learning.

Problem-based learning has been used in medical school in a number of different countries around the world for over 50 years, with both undergraduate and graduate students. Instead of the traditional lectures, laboratory practical classes and tutorial system of education, students in small groups are presented with a problem that they must try to solve. They are assisted by a 'facilitator' who helps them formulate the problem and generally advises them but does not supply information.

Interference by anti-cancer chemotherapeutic agents in the MTT-tumor chemosensitivity assay.

Background: One of the major goals of oncology is to predict the response of patients with cancer to chemotherapeutic agents by employing laboratory methods variously called 'tumor chemosensitivity assays', 'drug response assays', or 'drug sensitivity assays', in vitro. The MTT assay is one of the methods used to predict the drug response in malignancies. However, it may suffer from interference by the anticancer drugs with the MTT assay.

Fucoidan modulates the effect of transforming growth factor (TGF)-beta1 on fibroblast proliferation and wound repopulation in in vitro models of dermal wound repair.

Aberrant wound healing, either causing scarring or chronic wounds, is a significant cause of morbidity. There is therefore, considerable interest in agents which can modulate certain aspects of the wound healing process. Fucoidans, sulphated polyfucose polysaccharides which may be extracted from Fucus spp.

The effect of chitin and chitosan on fibroblast-populated collagen lattice contraction.

The effects of chitin [(1-->4)-2-acetamido-2-deoxy-beta-D-glucan] and its partially deacetylated derivatives, chitosans, on the human dermal fibroblast-mediated contraction of collagen lattices were examined in vitro as a model for the contraction of cutaneous wounds in vivo. Chitosan CL313A, a short-chain-length 89% deacetylated chitosan chloride, inhibited fibroblast-populated collagen lattice (FPCL) contraction at higher initial concentrations (500 and 1,000 microg/ml) in FPCLs fabricated with responsive dermal fibroblasts, while in FPCLs containing non-responsive fibroblasts inhibition of contraction was reduced. The responsive and non-responsive phenotype of human dermal fibroblasts to treatment with chitosan CL313A has been reported previously by us.

Characterization of the living skin equivalent as a model of cutaneous re-epithelialization.

The living skin equivalent, a three-dimensional organotypic model, has been widely used to investigate many aspects of cutaneous biology. However, there are relatively few studies assessing how faithfully the skin equivalent reproduces normal skin biology. The skin equivalent was fabricated by seeding human epidermal keratinocytes onto the upper surface of a hydrated collagen lattice populated with human dermal fibroblasts and subsequently raised to the air-liquid interface where keratinocyte stratification and differentiation led to the formation of a tissue which showed many common morphological features to that of normal skin.