Effects of oxygen tension and IGF-I on HIF-1α protein expression in mouse blastocysts.

PURPOSE: Hypoxia inducible factors (HIFs) are key regulators of oxygen homeostasis in response to reduced oxygenation in somatic cells. In addition, HIF-1α protein can be also induced by insulin-like growth factor I (IGF-I) treatment in various cell lines under normoxic condition. However, the expression and function of HIF-1α in embryogenesis are still unclear. Therefore, the objectives of this study were to examine the expression of HIF-1α in mouse blastocysts cultured under hypoxic and normoxic conditions, and to determine whether oxygen tension and IGF-I influence embryonic development through stimulation of HIF-1α expression. METHODS: Mouse embryos were cultured from the 1-cell to blastocyst stage under 5 % or 20 % O(2) in both the absence and presence of IGF-I. RESULTS: The embryonic development rates to the blastocyst stage were not affected by oxygen tension or IGF-I treatment. HIF-1α protein was localized to the cytoplasm of blastocysts, and its levels were independent of oxygen concentration or IGF-I treatment. Blastocysts cultured under 5 % O(2) exhibited significantly higher total cell numbers (83.4 ± 18.1) and lower apoptotic index (3.7 ± 1.5) than those cultured under 20 % O(2) (67.4 ± 15.6) (6.9 ± 3.5) (P<0.05). IGF-I reduced the apoptotic index in both oxygen conditions, but a significant decrease was detected in the 20 % O(2) group. CONCLUSIONS: HIF-1α may not be a major mediator that responds to change in oxygen tension within blastocysts, inconsistent with that of somatic cells. Supplementation of culture media with IGF-I has been shown to promote embryo development by an anti-apoptotic effect, instead of increasing HIF-1α protein expression.

An Effective Method of Teaching Advanced Cardiac Life Support (ACLS) Skills in Simulation-Based Training.

PURPOSE: In this study, we compared the effects of constructivist and traditional teaching strategies in teaching advanced cardiac life support (ACLS) skills during simulation-based training (SBT). METHODS: A randomized, pre- and post-test control group study was designed to examine this issue in 29 third-year emergency medical technician (EMT) students. Participants received SBT through constructivist SBT (CSBT) or traditional lecture-based SBT (TSBT) teaching strategies. We evaluated the effects of the simulation training on ACLS knowledge, and performance immediately after practice and at retention. RESULTS: The knowledge and performance of the CSBT group were higher than compared with the TSBT group (mean knowledge 33.3+/-5.03 vs. 29.5+/-5.33, p=0.36; and mean performance 12.20+/-1.85 vs. 8.85+/-3.54, p=0.010). However, there was no difference between two groups in retention between groups 1 month later (mean knowledge 31.86+/-4.45 vs. 31.50+/-4.65, p=0.825; and mean performance 12.13+/-0.99 vs. 12.57+/-1.78, p=0.283). CONCLUSION: CSBT is more effective with regard to knowledge acquisition and performance than TSBT. Further studies are needed to explore ways of improving retention and transfer of knowledge from simulated to real situations with SBT.

Effect of emotional intelligence on patient-physician interaction scores of clinical performance examination.

PURPOSE: The patient-physician interaction (PPI) is a critical part of the clinical encounter. Recent studies have emphasized the importance of the emotional intelligence (EI) of physician in the PPI. Despite emphasizing the EI, previous studies offer limited evidence regarding the effect of a student's EI on the PPI. The purpose of this study is to explore the differences in EI depending on the demographics of medical students and the correlation between EI and PPI scores. METHODS: The sample was 85 fourth-grade medical students. Prior to taking a 12-station clinical performance examination, the students completed questionnaires on their own perception of the EI, which included 5 domains and 50 items. The tool that was used to assess the level of EI was Moon's modified version of the EI test for adults. We investigated differences in EI depending on the demographics of medical students by ANOVA and noted a correlation between EI and PPI scores by stepwise multiple regression analysis. RESULTS: This study found that females or graduate entry students have higher EI scores and that 25 to 30-year-old students have higher EI scores than aged under 25 years. The PPI scores correlated positively with total EI scores (r=0.32) and 2 subdomains (perception and expression of emotion, r=0.26; empathy, r=0.33). Two subdomains were the best predictors of PPI score (R2=0.171). CONCLUSION: EI correlates significantly with PPI score and affects it. We conclude that EI is a key influence of the PPI. Further research is required to explore whether this is a consistent effect.

The Change of CPX Scores according to Repeated CPXs.

PURPOSE: Most medical schools have held clinical skills training programs recently. Despite these educational endeavors, few studies have attempted to address the effect of clinical skills assessments on clinical performance. This study investigated whether repeated experiences with the examination improved medical students' history-taking, physical exams, and patient-physician interactions (PPIs). METHODS: The subjects of the study were 101 4th-year medical students who participated in the clinical performance examination (CPX) 3 times. They completed their core clerkship before acquiring the first CPX scores; we tracked down the scores of three sets of CPX for 3 subdomains (history taking, physical exam, and patient-physician interaction) and investigated the changes in these scores. Additionally, we classified the research subjects into 3 groups by total CPX score-higher (upper 30%, n=30), intermediate (medium 40%, n=40), and lower (lower 30%, n=30)-and compared the curves for each group. RESULTS: Significant improvements were made on history taking and physical exam (F=130.786/237.358, p<0.01), while proficiency on the PPI declined (F=17.621, p<0.01). Additionally, scores in all levels improved continuously on history taking and physical exam, while students of the high and low levels experienced a sharp decline on the PPI (F=11.628, p<0.01). CONCLUSION: Improvement in the history-taking score reflects an accumulation of clinical knowledge and clinical exposure. Improvement on the physical exam score is affected by repeated practice on similar or identical cases and receipt of feedback. That PPI can deteriorate might be an effect of one's negative experience in a clinical clerkship.

Application of two different synthetic sequential media for the human IVF-ET program: a prospective, randomized, and comparative study.

OBJECTIVE: Since IVF program was first established, various types of media and culture systems have been developed either in-house or commercially. The aim of this study was to compare the efficacy of in-house Maria Research Center (MRC) media to that of commercially available Sydney IVF media in human day 3 embryo transfer cycles. METHODS: Three hundred sixty nine couples were included in this prospective, randomized, and comparative study. All couples undergoing IVF treatment at the Maria Fertility Hospital were randomly assigned to either Sydney IVF (n=178) or MRC (n=191) media. RESULTS: No difference was observed between the MRC media and Sydney IVF media groups with respect to fertilization rate (74.4% vs. 75.5%). The clinical pregnancy and implantation rates of MRC media (47.1% and 20.0%, respectively) were also similar to those of Sydney IVF media (44.4% and 19.4%, respectively). However, the proportion of embryos with good quality on day 3 was significantly higher in the MRC media group than the Sydney IVF media group (50.2% vs. 43.2%) (p<0.05). CONCLUSION: MRC media were as effective as Sydney IVF media for sustaining embryo development and pregnancy rates. The present study implies that MRC media can be a suitable alternative to commercially available media for human IVF-ET program.

A systematic review of training that use an integrated patient simulator.

The purpose of this article is to systematically review the literature that describes training and assessment that use an integrated patient simulator (IPS). We also tried to determine how to train learners with simulators, plan, and perform research on simulator-based education. Literature searches were conducted to identify articles from PubMed, EMBASE, and KMbase that were related to training and assessment that use an IPS, published from January 1999 to September 2008. Forty articles met the criteria and were analyzed. The results were as follows: Studies on IPS are the most common in graduate medical education (GME). The impact of IPS-based education is relatively greater in GME versus undergraduate medical education (UME) or continuing medical education (CME). IPS research in GME is characterized by addressing the effectiveness of clinical application, the training of procedures, and algorithms, rather than knowledge or simple skills. And research design is more elaborate in GME than UME or CME. IPS training in CME focuses mostly on specific clinical skills. Most training sessions in UME are offered to groups, but assessment is performed for a single student. Also, inter-rater reliability is checked unsatisfactorily in UME. IPS research in UME is characterized by limitations in design due to connections to the regular curriculum. According to findings above, we propose that: more detailed research design should be performed to overcome the limitations of UME research. For GME, increasing simulator-based training opportunities is desired, because its effectiveness and adaptability are relatively high.

MHC independent anti-tumor immune responses induced by Hsp70-enriched exosomes generate tumor regression in murine models.

The ideal cancer vaccine should work regardless of MHC types but currently the barrier generated by MHC specificity hampers the development of human cancer vaccines, requesting to identify strong immunogenic molecules that can induce anti-cancer immune responses without being affected by MHC polymorphism. Tumor-derived exosomes are small membrane vesicles containing tumor antigens as well as other immunologically important molecules such as MHC molecules and heat shock proteins (HSPs). Because of their potential immunogenicity, the plausible utility of tumor-derived exosomes as an MHC independent cancer vaccine was proposed. Here, we investigated whether Hsp70-enriched tumor exosomes can induce stronger immunogenicity as compared to normal tumor-derived exosomes in autologous as well as allogeneic murine models in vitro and in vivo. Western blotting showed that the exosomes of heat-treated tumor cells (HS Exo) contained higher amounts of Hsp70 than the exosomes of untreated cells (CNTL Exo). In both MHC type-identical and -irrelevant antigen-presenting cell models in vitro, HS Exo triggered the increased expressions of MHC class II molecules. Crucially, HS Exo performed greater therapeutic capability in regressing pre-established MHC type-identical and -irrelevant tumors than CNTL Exo in vivo. The analyses of anti-tumor function in allogeneic mouse model demonstrated that HS Exo elicited Th1-polarized immune responses defined by the increased productions of IgG2a and IFN-gamma. In summary, the Hsp70-enriched exosomes extracted from heat-treated tumors induced strong Th1 immune responses, resulting in eliminating cancer cells in allogeneic hosts in vivo. These results indicate that HS Exo is a potent MHC independent cell-free cancer therapeutic agent that can be developed for clinical trials.

Protective effect of diallyl disulfide on oxidative stress-injured neuronally differentiated PC12 cells.

The effects of diallyl disulfide (DADS), a garlic-derived compound, on the viability of neuronal cells and cell signals, including phosphatidylinositol 3-kinase (PI3K)/Akt, glycogen synthase kinase-3 (GSK-3), cytochrome c, caspase-3, and poly(ADP-ribose) polymerase (PARP), were investigated in PC12 cells neuronally differentiated by nerve growth factor. To evaluate the toxicity of DADS itself, nPC12 cells were treated with several concentrations of DADS, and 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and trypan blue stain revealed that the viability was not affected by low concentration of DADS, up to 20 microM, but it was decreased at higher than this concentration. The levels of free radicals and membrane lipid peroxidation were significantly increased in nPC12 cells when treated with more than 50 microM DADS, and treatment of PC12 cells with 100 microM DADS killed the cells by inhibiting PI3K/Akt and by promoting activation of GSK-3 and caspase-3, release of cytochrome c, and cleavage of PARP. To evaluate the protective effects of low concentration of DADS on oxidative stress-injured nPC12 cells, the viability of the cells (pretreated with DADS for 2 h vs. not pretreated) was evaluated 24 h after exposure to 100 microM H2O2 for 30 min. Compared to the cells treated with 100 microM H2O2 only, pretreatment of the cells with 20 microM DADS before exposure to 100 microM H2O2 increased the viability and induced activation of PI3K and Akt, inactivation of GSK-3, and inhibition of cytochrome c release, caspase-3 activation, and PARP cleavage. These results indicate that low concentration of DADS has neuroprotective effects by activating PI3K/Akt and by inhibiting GSK-3 activation, cytochrome c release, caspase-3 activation, and PARP cleavage, whereas high concentration is rather cytotoxic. Therefore, some specific optimum concentration of DADS may be a new potential therapeutic strategy for oxidative stress injured in vitro model of neurodegenerative diseases.