MATERIALS AND METHODS: MCQ items in papers taken from Year II Parts A, B and C examinations for Sessions 2001/02, and Part B examinations for 2002/03 and 2003/04, were analysed to obtain their difficulty indices and discrimination indices. Each paper consisted of 250 true/false items (50 questions of 5 items each) on topics drawn from different disciplines. The questions were first constructed and vetted by the individual departments before being submitted to a central committee, where the final selection of the MCQs was made, based purely on the academic judgement of the committee.
RESULTS: There was a wide distribution of item difficulty indices in all the MCQ papers analysed. Furthermore, the relationship between the difficulty index (P) and discrimination index (D) of the MCQ items in a paper was not linear, but more dome-shaped. Maximal discrimination (D = 51% to 71%) occurred with moderately easy/difficult items (P = 40% to 74%). On average, about 38% of the MCQ items in each paper were "very easy" (P > or =75%), while about 9% were "very difficult" (P <25%). About two-thirds of these very easy/difficult items had "very poor" or even negative discrimination (D < or =20%).
CONCLUSIONS: MCQ items that demonstrate good discriminating potential tend to be moderately difficult items, and the moderately-to-very difficult items are more likely to show negative discrimination. There is a need to evaluate the effectiveness of our MCQ items.
MATERIALS AND METHODS: Lecturers and students in the Phase (Year) II programme were asked to fill questionnaires following the second and fourth PBL cases. The two sets of survey responses were compared to see whether the students' and teachers' perceptions had changed over the 5-month period.
RESULTS: Students' responses from both surveys (1 and 2) were similar in that a majority agreed that the PBL tutorials had encouraged the seeking of information (66% and 67%, respectively), had improved understanding (57% and 56%), integration (65% and 70%) and application (50% and 64%) of knowledge. However, the views given in the form of written comments, following their positive responses, were somewhat contradictory. A large number of students (38% and 40%) faced difficulties in getting involved in discussions during the PBL tutorial and a majority (73% and 82%) preferred the normal subject-based tutorials. The reasons given by approximately 20% of the students were that the subject-based tutorials were more efficient for obtaining information and/or that the information had been pre-selected by the lecturers. More than 80% of the lecturers (in both surveys) perceived that the students had identified the appropriate learning objectives and covered the subject matter. The percentage of lecturers who agreed that PBL tutorials encouraged rapport and teamwork amongst students had increased in the second survey, from 70% to 92% and 55% to 83% respectively.
CONCLUSION: Implementing PBL is not simply a matter of developing new teaching materials and new effective ways of presenting them. It requires a paradigm shift, a change in the roles of students and teachers, and time.
PRINCIPAL FINDINGS: The serum antigen concentration-time profile of the N. sumatrana venom and its major toxins injected intravenously fitted a two-compartment model of pharmacokinetics. The systemic clearance (91.3 ml/h), terminal phase half-life (13.6 h) and systemic bioavailability (41.9%) of N. sumatrana venom injected intramuscularly were similar to those of N. sputatrix venom determined in an earlier study. The venom neurotoxin and cardiotoxin reached their peak concentrations within 30 min following intramuscular injection, relatively faster than the phospholipase A2 and whole venom (Tmax=2 h and 1 h, respectively). Rapid absorption of the neurotoxin and cardiotoxin from the injection site into systemic circulation indicates fast onsets of action of these principal toxins that are responsible for the early systemic manifestation of envenoming. The more prominent role of the neurotoxin in N. sumatrana systemic envenoming is further supported by its significantly higher intramuscular bioavailability (Fi.m.=81.5%) compared to that of the phospholipase A2 (Fi.m.=68.6%) or cardiotoxin (Fi.m.=45.6%). The incomplete absorption of the phospholipase A2 and cardiotoxin may infer the toxins' affinities for tissues at the injection site and their pathological roles in local tissue damages through synergistic interactions.
CONCLUSION/SIGNIFICANCE: Our results suggest that the venom neurotoxin is absorbed very rapidly and has the highest bioavailability following intramuscular injection, supporting its role as the principal toxin in systemic envenoming.