The synthesis of photoluminescent Cr(III) complexes of the type [Cr(diimine)(2)(DPPZ)](3+) are described, where DPPZ is the intercalating dipyridophenazine ligand, and diimine corresponds to the ancillary ligands bpy, phen, DMP, and TMP (where bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, DMP = 5,6-dimethyl-1,10-phenanthroline, and TMP = 3,4,7,8-tetramethyl-1,10-phenanthroline). For TMP, DMP, and phen as ancillary ligands, the complexes have also been resolved into their Lambda and Delta optical isomers. A comparison of the photophysical and electrochemical properties reveal similar (2)E(g) --> (4)A(2g) (O(h)) emission wavelengths and lifetimes, and a variation of 110 mV in the (2)E(g) excited state oxidizing power. A detailed investigation has been undertaken of ancillary ligand effects on the DNA binding of these complexes with a range of polynucleotides. For all four complexes, emission is quenched by the addition of calf thymus B-DNA, with the emission lifetime data yielding bimolecular quenching rate constants close to the diffusion controlled limit. Equilibrium dialysis studies have established a general predilection for AT base binding sites, while companion experiments with added distamycin (a selective minor groove binder) provide evidence for a minor groove binding preference. For the case of [Cr(TMP)(2)(DPPZ)](3+), concomitant equilibrium dialysis and circular dichroism measurements have demonstrated very strong enantioselective binding by the Lambda optical isomer. The thermodynamics of DNA binding have also been explored via isothermal titration calorimetry (ITC). The ITC data establish that the primary binding mode for all four Cr(III) complexes is entropically driven, a result that is attributed to the highly favorable free energy contribution associated with the hydrophobic transfer of the Cr(III) complexes from solution into the DNA binding site.

IntroductionResident physicians may have difficulty with identifying and managing pediatric septic shock due to limited patient encounters. Simulation-based interventions can enhance competency. We developed a low-fidelity tabletop simulation game to teach pediatric septic shock and compared residents' knowledge of and comfort with recognition and management of septic shock.MethodsPediatric and emergency medicine residents participated in an education session involving a low-fidelity, tabletop simulation in which they managed two simulated pediatric patients with septic shock. The two patients were a 12-year-old healthy male with cold shock due to a urinary tract infection and a 5-year-old female with a history of leukemia who developed warm shock due to pneumonia. Because this session was presented as a board game rather than high-fidelity simulation, learners focused on decision making rather than the mechanics of procedures. Residents completed a survey and a knowledge-based test before and after this session.ResultsTwenty-three pediatric and nine emergency medicine residents participated. Correct responses for the preintervention test were 71%, compared with 83% postintervention. The difference in rates was 12% (95% confidence interval, −0.17 to −0.07; p < .0001). Residents rated this modality as being more useful than lectures or reading and as equivalent to bedside teaching and high-fidelity simulation.DiscussionOur pilot low-fidelity simulation improved resident knowledge and comfort with pediatric septic shock care. Further studies are needed to address the impact of low-fidelity simulations on patient outcomes.

This case reviews the management of a 27-year-old pregnant female in myasthenic crisis. She presented to the emergency department in respiratory distress refractory to standard therapy, necessitating airway and ventilatory support and treatment with plasmapheresis. Myasthenic crisis in the setting of pregnancy is rare and presents unique management challenges for emergency physicians.

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