The maintenance of pure primary lymphocytes culture for long periods may be difficult because of its inability to divide continuously. In addition, lymphocytes separation methods such as Ficoll-Paque, RBC lysis and immunomagnetic microbeads separation may have some affect on cell viability. The objective of this study is to determine various types of lymphocytes purification methods, in order to prolong primary lymphocytes culture to 72 hours. The second objective is to use these primary lymphocytes as targets for quantitative and qualitative cell viability assays when analysing the action of toxins isolated from natural products. Human blood was drawn and purified by using Ficoll-Paque, RBC lysis or immunomagnetic separation column method in various combinations. The purified lymphocytes were also grown with and without the growth enhancement factor, concanavalin-A. Cell viability assays were carried out for 72 hours at 24 hours interval. The lymphocytes purified using RBC lysis method, with or without concanavalin-A can prolong 100% cell viability for 72 hours whilst lymphocytes purified using Ficoll-Paque and supplemented with concanavalin-A showed an increase in cell viability of over 250% at 72 hours incubation. It was observed only lymphocytes purified using Ficoll-Paque followed by the immunomagnetic microbeads separation method and supplemented with concanavalin-A showed overall cell viability increase, reaching 300% at 72 hours incubation. This method was a reliable model to test the cytotoxicity of the Bacillus thuringiensis parasporal inclusion, suggesting that the method achieves the objectives of the study.

PURPOSE: Problem-based learning (PBL) is usually conducted in small-group learning sessions with approximately eight students per facilitator. In this study, we implemented a modified version of PBL involving collaborative groups in an undergraduate chiropractic program and assessed its pedagogical effectiveness. METHODS: This study was conducted at the International Medical University, Kuala Lumpur, Malaysia, and involved the 2012 chiropractic student cohort. Six PBL cases were provided to chiropractic students, consisting of three PBL cases for which learning resources were provided and another three PBL cases for which learning resources were not provided. Group discussions were not continuously supervised, since only one facilitator was present. The students' perceptions of PBL in collaborative groups were assessed with a questionnaire that was divided into three domains: motivation, cognitive skills, and perceived pressure to work. RESULTS: Thirty of the 31 students (97%) participated in the study. PBL in collaborative groups was significantly associated with positive responses regarding students' motivation, cognitive skills, and perceived pressure to work (P<0.05). The students felt that PBL with learning resources increased motivation and cognitive skills (P<0.001). CONCLUSION: The new PBL implementation described in this study does not require additional instructors or any additional funding. When implemented in a classroom setting, it has pedagogical benefits equivalent to those of small-group sessions. Our findings also suggest that students rely significantly on available learning resources.
Chiropractic* ; Cohort Studies ; Financial Management ; Humans ; Learning ; Malaysia* ; Motivation ; Problem-Based Learning*