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PubMed2004

A multidisciplinary approach to teach responses to weapons of mass destruction and terrorism using combined simulation modalities.

STUDY OBJECTIVE: To reinforce concepts presented in the lectures; understand the complexity and speed of casualty and information generation during a Weapons of Mass Destruction and Terrorism (WMD/T) event; experience the novelty of combined weapons' effects; recognize the time course of the various chemical, biological, and radiation agents; and make challenging decisions with incomplete and conflicting information. SETTINGS: Two environments simulated simultaneously: one a major trauma center emergency room (ER) with two patient simulators and several human actors; the other an Emergency Operations Command Center (EOC). TARGET AUDIENCE: Students for this course included: clinicians, scientists, military and intelligence officers, lawyers, administrators, and logistic personnel whose jobs involve planning and executing emergency response plans to WMD/T. SIMULATION SCRIPT: A WMD/T attack in Washington, D.C., has occurred. Clinical students performed in their real life roles in the simulated ER, while nonclinical students did the same in the simulated EOC. Six ER casualties with combined WMD/T injuries were presented and treated over 40 minutes. In the EOC, each person was given his or her role title with identification tag. The EOC scenario took cues from the action in the ER via two television (TV) news feeds and telephone calls from other Emergency Operations Assets. PERFORMANCE EXPECTATIONS: Students were expected to actively engage in their roles. Student performances were self-evaluated during the debriefing. DEBRIEFING: The two groups were reunited and debriefed utilizing disaster crisis resource management tools. ASSESSMENT OF EFFECTIVENESS: Students answered an 18-point questionnaire to help evaluate the usefulness and acceptance of multimodality patient simulation. LESSONS LEARNED: Large-scale multimodality patient simulation can be used to train both clinicians and nonclinicians for future events of WMD/T. Students accepted the simulation experience and thought that scenario was appropriately realistic, complex, and overwhelming. Difficulties include the extensive man-hours involved in designing and presenting the live simulations. EOC-only sessions could be staged with only a few video cassette recorders, TVs, telephones, and callers.

Disasters↗
PubMed2006

Coarse-grained molecular dynamics simulations of membrane proteins and peptides.

Molecular dynamics (MD) simulations provide a valuable approach to the dynamics, structure, and stability of membrane-protein systems. Coarse-grained (CG) models, in which small groups of atoms are treated as single particles, enable extended (>100 ns) timescales to be addressed. In this study, we explore how CG-MD methods that have been developed for detergents and lipids may be extended to membrane proteins. In particular, CG-MD simulations of a number of membrane peptides and proteins are used to characterize their interactions with lipid bilayers. CG-MD is used to simulate the insertion of synthetic model membrane peptides (WALPs and LS3) into a lipid (PC) bilayer. WALP peptides insert in a transmembrane orientation, whilst the LS3 peptide adopts an interfacial location, both in agreement with experimental biophysical data. This approach is extended to a transmembrane fragment of the Vpu protein from HIV-1, and to the coat protein from fd phage. Again, simulated protein/membrane interactions are in good agreement with solid state NMR data for these proteins. CG-MD has also been applied to an M3-M4 fragment from the CFTR protein. Simulations of CFTR M3-M4 in a detergent micelle reveal formation of an alpha-helical hairpin, consistent with a variety of biophysical data. In an I231D mutant, the M3-M4 hairpin is additionally stabilized via an inter-helix Q207/D231 interaction. Finally, CG-MD simulations are extended to a more complex membrane protein, the bacterial sugar transporter LacY. Comparison of a 200 ns CG-MD simulation of LacY in a DPPC bilayer with a 50 ns atomistic simulation of the same protein in a DMPC bilayer shows that the two methods yield comparable predictions of lipid-protein interactions. Taken together, these results demonstrate the utility of CG-MD simulations for studies of membrane/protein interactions.

Amino Acid Sequence↗
PubMed2000

Molecular dynamics simulations of the d(CCAACGTTGG)(2) decamer: influence of the crystal environment.

Molecular dynamics (MD) simulations of the DNA duplex d(CCAACGTTGG)(2) were used to study the relationship between DNA sequence and structure. Two crystal simulations were carried out; one consisted of one unit cell containing two duplexes, and the other of two unit cells containing four duplexes. Two solution simulations were also carried out, one starting from canonical B-DNA and the other starting from the crystal structure. For many helicoidal parameters, the results from the crystal and solution simulations were essentially identical. However, for other parameters, in particular, alpha, gamma, delta, (epsilon - zeta), phase, and helical twist, differences between crystal and solution simulations were apparent. Notably, during crystal simulations, values of helical twist remained comparable to those in the crystal structure, to include the sequence-dependent differences among base steps, in which values ranged from 20 degrees to 50 degrees per base step. However, in the solution simulations, not only did the average values of helical twist decrease to approximately 30 degrees per base step, but every base step was approximately 30 degrees, suggesting that the sequence-dependent information may be lost. This study reveals that MD simulations of the crystal environment complement solution simulations in validating the applicability of MD to the analysis of DNA structure.

Computer Simulation↗
PubMed1996

The consistency of large concerted motions in proteins in molecular dynamics simulations.

A detailed investigation is presented into the effect of limited sampling time and small changes in the force field on molecular dynamics simulations of a protein. Thirteen independent simulations of the B1 IgG-binding domain of streptococcal protein G were performed, with small changes in the simulation parameters in each simulation. Parameters studied included temperature, bond constraints, cut-off radius for electrostatic interactions, and initial placement of hydrogen atoms. The essential dynamics technique was used to reveal dynamic differences between the simulations. Similar essential dynamics properties were found for all simulations, indicating that the large concerted motions found in the simulations are not particularly sensitive to small changes in the force field. A thorough investigation into the stability of the essential dynamics properties as derived from a molecular dynamics simulation of a few hundred picoseconds is provided. Although the definition of the essential modes of motion has not fully converged in these short simulations, the subspace in which these modes are confined is found to be reproducible.

Antigens, Bacterial↗
PubMed1999

Unrestrained stochastic dynamics simulations of the UUCG tetraloop using an implicit solvation model.

Three unrestrained stochastic dynamics simulations have been carried out on the RNA hairpin GGAC[UUCG] GUCC, using the AMBER94 force field (Cornell et al., 1995. J. Am. Chem. Soc. 117:5179-5197) in MacroModel 5.5 (Mohamadi et al., 1990. J. Comp. Chem. 11:440-467) and either the GB/SA continuum solvation model (Still et al., 1990. J. Am. Chem. Soc. 112:6127-6129) or a linear distance-dependent dielectric (1/R) treatment. The linear distance-dependent treatment results in severe distortion of the nucleic acid structure, restriction of all hydroxyl dihedrals, and collapse of the counterion atmosphere over the course of a 5-ns simulation. An additional vacuum simulation without counterions shows somewhat improved behavior. In contrast, the two GB/SA simulations (1.149 and 3.060 ns in length) give average structures within 1.2 A of the initial NMR structure and in excellent agreement with results of an earlier explicit solvent simulation (Miller and Kollman, 1997. J. Mol. Biol. 270:436-450). In a 3-ns GB/SA simulation starting with the incorrect UUCG tetraloop structure (Cheong et al., 1990. Nature. 346:680-682), this loop conformation converts to the correct loop geometry (Allain and Varani, 1995. J. Mol. Biol. 250:333-353), suggesting enhanced sampling relative to the previous explicit solvent simulation. Thermodynamic effects of 2'-deoxyribose substitutions of loop nucleotides were experimentally determined and are found to correlate with the fraction of time the ribose 2'-OH is hydrogen bonded and the distribution of the hydroxyl dihedral is observed in the GB/SA simulations. The GB/SA simulations thus appear to faithfully represent structural features of the RNA without the computational expense of explicit solvent.

Base Sequence↗
PubMed2002

Simulation of folding of a small alpha-helical protein in atomistic detail using worldwide-distributed computing.

By employing thousands of PCs and new worldwide-distributed computing techniques, we have simulated in atomistic detail the folding of a fast-folding 36-residue alpha-helical protein from the villin headpiece. The total simulated time exceeds 300 micros, orders of magnitude more than previous simulations of a molecule of this size. Starting from an extended state, we obtained an ensemble of folded structures, which is on average 1.7A and 1.9A away from the native state in C(alpha) distance-based root-mean-square deviation (dRMS) and C(beta) dRMS sense, respectively. The folding mechanism of villin is most consistent with the hydrophobic collapse view of folding: the molecule collapses non-specifically very quickly ( approximately 20ns), which greatly reduces the size of the conformational space that needs to be explored in search of the native state. The conformational search in the collapsed state appears to be rate-limited by the formation of the aromatic core: in a significant fraction of our simulations, the C-terminal phenylalanine residue packs improperly with the rest of the hydrophobic core. We suggest that the breaking of this interaction may be the rate-determining step in the course of folding. On the basis of our simulations we estimate the folding rate of villin to be approximately 5micros. By analyzing the average features of the folded ensemble obtained by simulation, we see that the mean folded structure is more similar to the native fold than any individual folded structure. This finding highlights the need for simulating ensembles of molecules and averaging the results in an experiment-like fashion if meaningful comparison between simulation and experiment is to be attempted. Moreover, our results demonstrate that (1) the computational methodology exists to simulate the multi-microsecond regime using distributed computing and (2) that potential sets used to describe interatomic interactions may be sufficiently accurate to reach the folded state, at least for small proteins. We conclude with a comparison between our results and current protein-folding theory.

Amino Acid Sequence↗
PubMed2002

Randomized prospective blinded study validating acquistion of ureteroscopy skills using computer based virtual reality endourological simulator.

PURPOSE: Surgical simulation has emerged in the last decade as a potential tool for aiding acquisition of technical skills, including anesthesia protocols, trauma management, cardiac catheterization and laparoscopy. We evaluate and validate the use of a computer based ureteroscopy simulator (URO Mentor, Simbionix Ltd., Lod, Israel) in the acquisition of basic ureteroscopic skills. MATERIALS AND METHODS: We assessed 20 novice trainees for the ability to perform basic ureteroscopic tasks on a computer based ureteroscopy simulator. Participants were randomized to receive individualized mentored instruction or no additional training, and subsequently underwent post-testing. Pre-training and post-training improvement in performance was assessed by objective simulator based measurements. Subjective overall performance was rated using a validated endourological global rating scale by an observer blinded to subject training status. RESULTS: Demographics and pre-test scores were similar between groups. Post-testing revealed a significant effect of training on objective and subjective measurements. Spearman rank correlation demonstrated a significant association between objective simulator based measurements and the endourological global rating scale. CONCLUSIONS: Use of a computer based ureteroscopy simulator resulted in rapid acquisition of ureteroscopic skills in trainees with no prior surgical training. Results of this study demonstrate the use of a virtual reality ureteroscopy simulator in endourological training. Correlation of simulator based measurements with a previously validated endourological global rating scale provides initial validation of the ureteroscopy simulator for the assessment of ureteroscopic skills.

Adult↗
PubMed1999

Comparison of prostate biopsy schemes by computer simulation.

OBJECTIVES: To compare the ability of different biopsy schemes to detect cancer and predict tumor volume using our previously described prostate biopsy simulation system. In addition, we used the simulation system to evaluate the optimal location of transition zone biopsies. METHODS: Digital reconstructions of 180 radical prostatectomy specimens were used. Forty simulations were performed on each prostate for 10 biopsy schemes, including a previously reported five-region peripheral zone biopsy pattern and a new 11-core multisite-directed scheme consisting of sextant, two transition zone, one midline, and two anterior horn biopsies. For simulation of the transition zone biopsies, paired near-midline biopsies were simulated, with needle insertion points from the apex to the base of the prostate and with needle advances of 1 to 4 cm before firing. A total of 1,180,800 individual biopsy tracks were simulated. RESULTS: The 11-core multisite-directed biopsy scheme had the highest detection rate for cancers greater than 0.5 cc. This scheme reliably detected cancer in 94% (138 of 147) of the cases. These results were significantly better than those of the sextant biopsy scheme (P <0.001) and the five-region 18-core peripheral zone scheme (P = 0.03). Compared with other schemes, there were increases in small-volume (0.5 cc or less) cancer detection by both the 11-core multisite-directed and five-region schemes, but they were not statistically significant. The multisite and the sextant plus four transition zone biopsy schemes had the best correlation of mean total core cancer length with total cancer volume. In the simulation of the transition zone biopsies, the highest detection rate was observed when the biopsies were initiated at the most apical section and inserted for a depth of 3 cm before firing. CONCLUSIONS: Our simulation results suggest that the detection rate of prostate biopsies is not related solely to the number of cores taken. Core placement (the regions of the prostate from which samples are taken) is also important. The 11-core multisite-directed biopsy scheme performed the best, with improved cancer detection rates and tumor volume correlation over other schemes. On the basis of our simulations, this scheme has been chosen for clinical evaluation.

Biopsy↗
PubMed2001

Virtual simulation in patients with breast cancer.

BACKGROUND: Investigation of the feasibility and effectiveness of virtual simulation in patients receiving radiotherapy of the breast. METHODS: Twenty-three patients were included in the study. All of them underwent a course of postoperative tangential breast irradiation. The patients were prospectively randomised into two groups. Group A patients (n=11) received a conventional computed tomography -based treatment planning, group B patients (n=12) a virtual simulation. The results of both treatment planning procedures were compared. RESULTS: The treatment planning was feasible in all patients. The time expenditure could be reduced from a median of 45.0 to 16.5 min and from 55.0 to 32.0 min for the technician and physician, respectively, using virtual simulation. Furthermore the treatment planning for the patient could be reduced from a median of 45.0 min in two sessions to 16.5 min in one session. The image quality of the digital reconstructed radiographs was satisfying compared to the simulation films. The incidence and extension of set-up corrections for the patients at the first treatment were comparable in both groups. The time interval between the planning CT and the first treatment could be reduced by 31% using virtual simulation due to the omission of the conventional simulation. CONCLUSION: The virtual simulation is a feasible tool for the treatment planning of patients undergoing tangential irradiation of the breast. Compared with the conventional simulation procedure virtual simulation is superior regarding to the precision of patients marking, the quality of the reference images and, the time expenditure for the patients and medical staff.

Breast Neoplasms↗
PubMed2006

On the application of accelerated molecular dynamics to liquid water simulations.

Our group recently proposed a robust bias potential function that can be used in an efficient all-atom accelerated molecular dynamics (MD) approach to simulate the transition of high energy barriers without any advance knowledge of the potential-energy landscape. The main idea is to modify the potential-energy surface by adding a bias, or boost, potential in regions close to the local minima, such that all transitions rates are increased. By applying the accelerated MD simulation method to liquid water, we observed that this new simulation technique accelerates the molecular motion without losing its microscopic structure and equilibrium properties. Our results showed that the application of a small boost energy on the potential-energy surface significantly reduces the statistical inefficiency of the simulation while keeping all the other calculated properties unchanged. On the other hand, although aggressive acceleration of the dynamics simulation increases the self-diffusion coefficient of water molecules greatly and dramatically reduces the correlation time of the simulation, configurations representative of the true structure of liquid water are poorly sampled. Our results also showed the strength and robustness of this simulation technique, which confirm this approach as a very useful and promising tool to extend the time scale of the all-atom simulations of biological system with explicit solvent models. However, we should keep in mind that there is a compromise between the strength of the boost applied in the simulation and the reproduction of the ensemble average properties.

Algorithms↗
PubMed2005

Molecular dynamics simulations of peptide-surface interactions.

Proteins, which are bioactive molecules, adsorb on implants placed in the body through complex and poorly understood mechanisms and directly influence biocompatibility. Molecular dynamics modeling using empirical force fields provides one of the most direct methods of theoretically analyzing the behavior of complex molecular systems and is well-suited for the simulation of protein adsorption behavior. To accurately simulate protein adsorption behavior, a force field must correctly represent the thermodynamic driving forces that govern peptide residue-surface interactions. However, since existing force fields were developed without specific consideration of protein-surface interactions, they may not accurately represent this type of molecular behavior. To address this concern, we developed a host-guest peptide adsorption model in the form of a G(4)-X-G(4) peptide (G is glycine, X is a variable residue) to enable determination of the contributions to adsorption free energy of different X residues when adsorbed to functionalized Au-alkanethiol self-assembled monolayers (SAMs). We have previously reported experimental results using surface plasmon resonance (SPR) spectroscopy to measure the free energy of peptide adsorption for this peptide model with X = G and K (lysine) on OH and COOH functionalized SAMs. The objectives of the present research were the development and assessment of methods to calculate adsorption free energy using molecular dynamics simulations with the GROMACS force field for these same peptide adsorption systems, with an oligoethylene oxide (OEG) functionalized SAM surface also being considered. By comparing simulation results to the experimental results, the accuracy of the selected force field to represent the behavior of these molecular systems can be evaluated. From our simulations, the G(4)-G-G(4) and G(4)-K-G(4) peptides showed minimal to no adsorption to the OH SAM surfaces and the G(4)-K-G(4) showed strong adsorption to the COOH SAM surface, which is in agreement with our SPR experiments. Contrary to our experimental results, however, the simulations predicted a relatively strong adsorption of G(4)-G-G(4) peptide to the COOH SAM surface. In addition, both peptides were unexpectedly predicted to adsorb to the OEG surface. These findings demonstrate the need for GROMACS force field parameters to be rebalanced for the simulation of peptide adsorption behavior on SAM surfaces. The developed methods provide a direct means of assessing, modifying, and validating force field performance for the simulation of peptide and protein adsorption to surfaces, without which little confidence can be placed in the simulation results that are generated with these types of systems.

Adsorption↗
PubMedDate not supplied

Prehospital and hospital-based health care providers' experience with a human patient simulator.

OBJECTIVES: To ascertain the level of acceptance of a human patient simulator as a training tool among a diverse group of health care providers. Secondary objectives were to elucidate its most useful aspects for training and find ways to improve upon the simulation experience. METHODS: A satisfaction survey was conducted regarding the use of a human patient simulator from July 1999 to February 2000. The survey consisted of five questions with a five-point Likert scale (5 being the most favorable score) and three questions that asked for qualitative written feedback on the simulator experience. The survey was handed to 78 consecutive participants immediately after their experiences and collected immediately after it was filled out to ensure a 100% response rate to the overall survey. Qualitative responses were placed into categories by theme, and a sum was calculated for each category. RESULTS: There was a high level of acceptance for simulation training among this diverse group, with Likert scores for the first two questions regarding general satisfaction of 4.74 +/- 0.126 (n = 77) and 4.77 +/- 0.126 (n = 78). Regarding the usefulness of each specific area of simulator training, the scores were 4.53 +/- 0.153 (n = 78) for patient assessment, 4.55 +/- 0.182 (n = 47) for treatment options, and 4.70 +/- 0.125 (n = 63) for response to treatment. There were 49 positive comments and nine negative comments. Realism (n = 26) and the ability to see response to treatment (n = 12) were the two most common positive comments. Negative comments focused on logistics of the simulator lab (n = 4) rather than the simulator itself. CONCLUSIONS: In this sample, prehospital and hospital-based health professionals were accepting of human patient simulation as a new teaching tool with multiple useful applications.

Consumer Behavior↗
PubMed2004

Validation of the GATE Monte Carlo simulation platform for modelling a CsI(Tl) scintillation camera dedicated to small-animal imaging.

Monte Carlo simulations are increasingly used in scintigraphic imaging to model imaging systems and to develop and assess tomographic reconstruction algorithms and correction methods for improved image quantitation. GATE (GEANT4 application for tomographic emission) is a new Monte Carlo simulation platform based on GEANT4 dedicated to nuclear imaging applications. This paper describes the GATE simulation of a prototype of scintillation camera dedicated to small-animal imaging and consisting of a CsI(Tl) crystal array coupled to a position-sensitive photomultiplier tube. The relevance of GATE to model the camera prototype was assessed by comparing simulated 99mTc point spread functions, energy spectra, sensitivities, scatter fractions and image of a capillary phantom with the corresponding experimental measurements. Results showed an excellent agreement between simulated and experimental data: experimental spatial resolutions were predicted with an error less than 100 microns. The difference between experimental and simulated system sensitivities for different source-to-collimator distances was within 2%. Simulated and experimental scatter fractions in a [98-182 keV] energy window differed by less than 2% for sources located in water. Simulated and experimental energy spectra agreed very well between 40 and 180 keV. These results demonstrate the ability and flexibility of GATE for simulating original detector designs. The main weakness of GATE concerns the long computation time it requires: this issue is currently under investigation by the GEANT4 and the GATE collaborations.

Animals↗
PubMed2004

Monte carlo simulation of x-ray spectra in diagnostic radiology and mammography using MCNP4C.

The general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C) was used for the simulation of x-ray spectra in diagnostic radiology and mammography. The electrons were transported until they slow down and stop in the target. Both bremsstrahlung and characteristic x-ray production were considered in this work. We focus on the simulation of various target/filter combinations to investigate the effect of tube voltage, target material and filter thickness on x-ray spectra in the diagnostic radiology and mammography energy ranges. The simulated x-ray spectra were compared with experimental measurements and spectra calculated by IPEM report number 78. In addition, the anode heel effect and off-axis x-ray spectra were assessed for different anode angles and target materials and the results were compared with EGS4-based Monte Carlo simulations and measured data. Quantitative evaluation of the differences between our Monte Carlo simulated and comparison spectra was performed using student's t-test statistical analysis. Generally, there is a good agreement between the simulated x-ray and comparison spectra, although there are systematic differences between the simulated and reference spectra especially in the K-characteristic x-rays intensity. Nevertheless, no statistically significant differences have been observed between IPEM spectra and the simulated spectra. It has been shown that the difference between MCNP simulated spectra and IPEM spectra in the low energy range is the result of the overestimation of characteristic photons following the normalization procedure. The transmission curves produced by MCNP4C have good agreement with the IPEM report especially for tube voltages of 50 kV and 80 kV. The systematic discrepancy for higher tube voltages is the result of systematic differences between the corresponding spectra.

Algorithms↗
PubMed2006

Dual-energy mammography: simulation studies.

This paper presents a mammography simulator and demonstrates its applicability in feasibility studies in dual-energy (DE) subtraction mammography. This mammography simulator is an evolution of a previously presented x-ray imaging simulation system, which has been extended with new functionalities that are specific for DE simulations. The new features include incident exposure and dose calculations, the implementation of a DE subtraction algorithm as well as amendments to the detector and source modelling. The system was then verified by simulating experiments and comparing their results against published data. The simulator was used to carry out a feasibility study of the applicability of DE techniques in mammography, and more precisely to examine whether this modality could result in better visualization and detection of microcalcifications. Investigations were carried out using a 3D breast software phantom of average thickness, monoenergetic and polyenergetic beam spectra and various detector configurations. Dual-shot techniques were simulated. Results showed the advantage of using monoenergetic in comparison with polyenergetic beams. Optimization studies with monochromatic sources were carried out to obtain the optimal low and high incident energies, based on the assessment of the figure of merit of the simulated microcalcifications in the subtracted images. The results of the simulation study with the optimal energies demonstrated that the use of the DE technique can improve visualization and increase detectability, allowing identification of microcalcifications of sizes as small as 200 microm. The quantitative results are also verified by means of a visual inspection of the synthetic images.

Algorithms↗
PubMed1991

Designing a neural network simulator--the MENS modelling environment for network systems: II.

During recent years, neural network research has been extended to a large number of different fields, increasingly attracting the interest of workers from various disciplines. The computer simulations carried out with this research require an appropriate software environment. The computational similarities of many kinds of simulations allow the design of software components that are largely independent of the specific application. These considerations are reflected, for example, by the general layout of the MENS network simulator, as described in the accompanying first paper. This paper presents the design considerations for the simulator's different software components in more detail. In particular, design and implementation are discussed with respect to computational and memory efficiency. The discussion includes, for example, the representation of a network by the simulator's data structure, the file-driven configuration and initialization of a network, the simulator's stimulus and monitor system, and the simulator's control structures. In addition, the separation and interaction of application-specific and application-independent software components are addressed. Particular performance aspects comprise the implementation of synaptic delays, the dynamic deletion of synaptic links in network learning, and the preprocessing of stimulus films. In addition, some general aspects of simulator performance and testing are considered. The material presented in this paper concerns both the development of new simulation software and the efficient use of existing programs. Therefore, both the general user as well as the software designer may hopefully benefit from this presentation.

Animals↗
PubMed2004

Simulation tools for biochemical networks: evaluation of performance and usability.

MOTIVATION: Simulation of dynamic biochemical systems is receiving considerable attention due to increasing availability of experimental data of complex cellular functions. Numerous simulation tools have been developed for numerical simulation of the behavior of a system described in mathematical form. However, there exist only a few evaluation studies of these tools. Knowledge of the properties and capabilities of the simulation tools would help bioscientists in building models based on experimental data. RESULTS: We examine selected simulation tools that are intended for the simulation of biochemical systems. We choose four of them for more detailed study and perform time series simulations using a specific pathway describing the concentration of the active form of protein kinase C. We conclude that the simulation results are convergent between the chosen simulation tools. However, the tools differ in their usability, support for data transfer to other programs and support for automatic parameter estimation. From the experimentalists' point of view, all these are properties that need to be emphasized in the future.

Animals↗
PubMed1992

Anesthesiologists' management of simulated critical incidents.

Human error is believed to contribute to the majority of negative anesthesia outcomes. Because retrospective analysis of critical incidents has several shortcomings and prospective studies are limited by the low frequency of critical incidents, an anesthesia simulator was used to evaluate the management of simulated emergency situations by ten anesthesia residents, ten faculty anesthesiologists, and ten anesthesiologists in private practice in order to identify specific patterns of errors in diagnosis and treatment. The simulator is a computer program that presents the patient, monitors, and management choices in a graphical display on an IBM or compatible personal computer. Many errors were observed in the management of these emergency situations, and even anesthesiologists with years of experience made serious errors. Although all experienced anesthesiologists correctly diagnosed simulated esophageal intubation, two residents misinterpreted the lack of end-tidal carbon dioxide. Only 40% of subjects correctly diagnosed simulated anaphylactic reaction; 27% adequately treated simulated myocardial ischemia; and 30% managed a simulated cardiac arrest according to Advanced Cardiac Life Support (ACLS) guidelines. Problems with continuous infusions of vasoactive agents were common. Fixation errors or failure to revise a plan in the presence of inconsistent cues were made by 63% of subjects. The subjects that gathered more information during simulated anaphylaxis made the correct diagnosis more often and made fewer treatment errors. The time since the last ACLS training was found to be an important predictor of correct management of simulated cardiac arrest.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaphylaxis↗