Stress responses in high-fidelity simulation and standard simulation training among medical students.

BACKGROUND: Simulation has been recognized as a shift in healthcare education that can improve skills and patient safety and outcomes. High-fidelity simulation of critical medical situations can be a source of stress among participants that can interfere with students' abilities leading to unexpected emotional responses. The aim of this study is to determine if two simulation methods, high-fidelity (HF) and procedural simulation (PS), may be associated with stress responses at a self-perceived and biological level (salivary cortisol variations), and to compare stress levels of the two different simulation method. We also wanted to find independent variables associated with cortisol total hormonal output. METHODS: A quasi-experimental before-after study was used including the administration of questionnaires, and biomarkers evaluation by salivary cortisol samples before and after simulation. A total of 148 students were eligible and agreed to participate in the study. We used paired T-test for mean comparison regarding State-trait anxiety for both HF and PT simulations. For NASA-TLX we performed a T-test mean comparison between groups. We used paired T-test mean comparison for cortisol analysis. Multivariable linear regression has been used to assess variables associated with AUCg values and perceived stress. RESULTS: values of STAI-Y scores were relatively higher at the end of the HF and PS sessions. NASA-TLX was significantly higher at baseline for the HF simulations, with respect to the PS simulation. Cortisol fold increase was significantly different in the two groups. Linear regression showed that cortisol AUCg was related to the STAI-Y score in both groups. CONCLUSION: Participating students developed a stress response both after in the HF and PS training, testified by psychological and biological outputs. According to our results, stress levels were increased for simply being in a simulation scenario than to the intrinsic complexity of the task required. More studies are needed to confirm this trend and to clarify the role of simulated stress response in a long-term learning scenario.

Challenges in industrial fermentation technology research.

Industrial fermentation processes are increasingly popular, and are considered an important technological asset for reducing our dependence on chemicals and products produced from fossil fuels. However, despite their increasing popularity, fermentation processes have not yet reached the same maturity as traditional chemical processes, particularly when it comes to using engineering tools such as mathematical models and optimization techniques. This perspective starts with a brief overview of these engineering tools. However, the main focus is on a description of some of the most important engineering challenges: scaling up and scaling down fermentation processes, the influence of morphology on broth rheology and mass transfer, and establishing novel sensors to measure and control insightful process parameters. The greatest emphasis is on the challenges posed by filamentous fungi, because of their wide applications as cell factories and therefore their relevance in a White Biotechnology context. Computational fluid dynamics (CFD) is introduced as a promising tool that can be used to support the scaling up and scaling down of bioreactors, and for studying mixing and the potential occurrence of gradients in a tank.

Heterologous expression and characterization of bacterial 2-C-methyl-D-erythritol-4-phosphate pathway in Saccharomyces cerevisiae.

Transfer of a biosynthetic pathway between evolutionary distant organisms can create a metabolic shunt capable of bypassing the native regulation of the host organism, hereby improving the production of secondary metabolite precursor molecules for important natural products. Here, we report the engineering of Escherichia coli genes encoding the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway into the genome of Saccharomyces cerevisiae and the characterization of intermediate metabolites synthesized by the MEP pathway in yeast. Our UPLC-MS analysis of the MEP pathway metabolites from engineered yeast showed that the pathway is active until the synthesis of 2-C-methyl-D-erythritol-2,4-cyclodiphosphate, but appears to lack functionality of the last two steps of the MEP pathway, catalyzed by the [4Fe-4S] iron sulfur cluster proteins encoded by ispG and ispH. In order to functionalize the last two steps of the MEP pathway, we co-expressed the genes for the E. coli iron sulfur cluster (ISC) assembly machinery. By deleting ERG13, thereby incapacitating the mevalonate pathway, in conjunction with labeling experiments with U-¹³C6 glucose and growth experiments, we found that the ISC assembly machinery was unable to functionalize ispG and ispH. However, we have found that leuC and leuD, encoding the heterodimeric iron-sulfur cluster protein, isopropylmalate isomerase, can complement the S. cerevisiae leu1 auxotrophy. To our knowledge, this is the first time a bacterial iron-sulfur cluster protein has been functionally expressed in the cytosol of S. cerevisiae under aerobic conditions and shows that S. cerevisiae has the capability to functionally express at least some bacterial iron-sulfur cluster proteins in its cytosol.

Sensitivity to lovastatin of Saccharomyces cerevisiae strains deleted for pleiotropic drug resistance (PDR) genes.

The use of statins is well established in human therapy, and model organisms such as Saccharomyces cerevisiae are commonly used in studies of drug action at molecular and cellular levels. The investigation of the resistance mechanisms towards statins may suggest new approaches to improve therapy based on the use of statins. We investigated the susceptibility to lovastatin of S. cerevisiae strains deleted for PDR genes, responsible for exporting hydrophobic and amphiphilic drugs, such as lovastatin. Strains deleted for the genes tested, PDR1, PDR3, PDR5 and SNQ2, exhibited remarkably different phenotypes, with deletion of PDR5 causing the highest sensitivity to lovastatin. The study helped clarifying which pdr mutants to use in studies of physiological actions of statins in yeast.

Reconstruction of a bacterial isoprenoid biosynthetic pathway in Saccharomyces cerevisiae.

A eukaryotic mevalonate pathway transferred and expressed in Escherichia coli, and a mammalian hydrocortisone biosynthetic pathway rebuilt in Saccharomyces cerevisiae are examples showing that transferring metabolic pathways from one organism to another can have a powerful impact on cell properties. In this study, we reconstructed the E. coli isoprenoid biosynthetic pathway in S. cerevisiae. Genes encoding the seven enzymatic steps of the pathway were cloned and expressed in S. cerevisiae. mRNA from the seven genes was detected, and the pathway was shown able to sustain growth of yeast in conditions of inhibition of its constitutive isoprenoid biosynthetic pathway.