MATERIALS AND METHODS: A survey of the tutors who had used the instrument was conducted to determine whether the assessment instrument or form was user-friendly. The 4 competencies assessed, using a 5-point rating scale, were (1) participation and communication skills, (2) cooperation or team-building skills, (3) comprehension or reasoning skills and (4) knowledge or information-gathering skills. Tutors were given a set of criteria guidelines for scoring the students' performance in these 4 competencies. Tutors were not attached to a particular PBL group, but took turns to facilitate different groups on different case or problem discussions. Assessment scores for one cohort of undergraduate medical students in their respective PBL groups in Year I (2003/2004) and Year II (2004/2005) were analysed. The consistency of scores was analysed using intraclass correlation.
RESULTS: The majority of the tutors surveyed expressed no difficulty in using the instrument and agreed that it helped them assess the students fairly. Analysis of the scores obtained for the above cohort indicated that the different raters were relatively consistent in their assessment of student performance, despite a small number consistently showing either "strict" or "indiscriminate" rating practice.
CONCLUSION: The instrument designed for the assessment of student performance in the PBL tutorial classroom setting is user-friendly and is reliable when used judiciously with the criteria guidelines provided.
SIGNIFICANCE: A shotgun proteomic approach adopted in this study revealed the compositional details of the venom of common tiger snake from Australia, Notechis scutatus. The proteomic findings provided additional information on the relative abundances of toxins and the detection of proteins of minor expression unreported previously. The potent lethal effect of the venom was neutralized by bioCSL Sea Snake Antivenom, an anticipated finding due to the fact that the Sea Snake Antivenom is actually bivalent in nature, being raised against a mix of venoms of the beaked sea snake (Hydrophis schistosus) and N. scutatus. However, it is surprising to note that bioCSL Sea Snake Antivenom neutralized N. scutatus venom much more effectively compared to the targeted sea snake venom by a marked difference in potency of approximately 6-fold. This phenomenon may be explained by the main difference in the proteomes of the two venoms, where H. schistosus venom is dominated by short-neurotoxins in high abundance - this is a poorly immunogenic toxin group that has been increasingly recognized in the venoms of a few cobras. Further investigations should be directed toward strategies to improve the neutralization of short-neurotoxins, in line with the envisioned production of an effective pan-regional elapid antivenom.
Methods: This study investigated the cytotoxic effect of the venom from Trimeresurus purpureomaculatus, the mangrove pit viper (also known as shore pit viper) which is native in Malaysia, across a panel of human cancer cell lines from breast, lung, colon and prostate as well as the corresponding normal cell lines of each tissue.
Results: The venom exhibited dose-dependent cytotoxic activities on all cell lines tested, with median inhibition concentrations (IC50) ranging from 0.42 to 6.98 µg/mL. The venom has a high selectivity index (SI = 14.54) on breast cancer cell line (MCF7), indicating that it is significantly more cytotoxic toward the cancer than to normal cell lines. Furthermore, the venom was fractionated using C18 reversed-phase high-performance liquid chromatography and the anticancer effect of each protein fraction was examined. Fraction 1 that contains a hydrophilic low molecular weight (approximately 7.5 kDa) protein was found to be the most cytotoxic and selective toward the breast cancer cell line (MCF7). The protein was identified using liquid chromatography-tandem mass spectrometry as a venom disintegrin, termed purpureomaculin in this study.
Conclusion: Taken together, the findings revealed the potent and selective cytotoxicity of a disintegrin protein isolated from the Malaysian T. purpureomaculatus venom and suggested its anticancer potential in drug discovery.