Association Between American Board of Surgery Initial Certification and Medical Malpractice Payments.

OBJECTIVE: To measure associations between surgeons' examination performance and obtaining American Board of Surgery certification with the likelihood of having medical malpractice payments. BACKGROUND: Further research is needed to establish a broader understanding of the association of board certification and patient and practice outcomes. METHODS: Retrospective analysis using propensity score-matched surgeons who attempted to obtain American Board of Surgery certification. Surgeons who completed residency between 2000 and 2019 (n=910) and attempted to become certified were categorized as certified or failing to obtain certification. In addition, groups were categorized as either passing or failing their first attempt on the qualifying and certifying examinations. Malpractice payment reports were dichotomized for surgeons who either had a payment report or not. RESULTS: The hazard rate (HR) of malpractice payment reports was significantly greater for surgeons who attempted and failed to obtain certification [HR=1.87; 95% confidence interval (CI), 1.28-2.74] than for surgeons who were certified. Moreover, surgeons who failed either the qualifying (HR=1.64; 95% CI, 1.14-2.37) or certifying examination (HR=1.72; 95% CI, 1.14-2.60) had significantly higher malpractice payment HRs than those who passed the examinations on their first attempt. CONCLUSIONS: Failing to obtain board certification was associated with a higher rate of medical malpractice payments. In addition, failing examinations in the certification examination process on the first attempt was also associated with higher rates of medical malpractice payments. This study provides further evidence that board certification is linked to potential indicators for patient outcomes and practice quality.

Quantum chemical modeling of reaction mechanism for 2-oxoglutarate dependent enzymes: effect of substitution of iron by nickel and cobalt.

Enzymatic hydroxylation reactions carried out by 2-oxoglutarate (2OG) dependent iron-containing oxygenases were recently implicated in oxygen sensing. In addition to oxygen depletion, two metals, cobalt and nickel, are capable of inducing hypoxic stress in cells by inhibiting oxygenase activity. Two possible scenarios have been proposed for the explanation of the hypoxic effects of cobalt and nickel: oxidation of enzyme-bound iron following cobalt or nickel exposure, and substitution of iron by cobalt or nickel. Here, by using density functional theory calculations, we modeled the reaction route from the reaction components to the high-spin metal-oxide intermediate in the activation of oxygen molecule by 2OG-dependent enzymes for three metal ions Fe(II), Ni(II), and Co(II) in the active site. An initial molecular model was constructed based on the crystal structure of iron-containing asparaginyl hydroxylase (FIH-1). Nickel- and cobalt-containing enzymes were modeled by a consequent replacement of the iron in the active center. The energy profiles connecting stationary points on the potential surfaces were computed by using the intrinsic reaction coordinate (IRC) technique from the located transition states. The results of calculations show that the substitution of iron by nickel or cobalt modifies the reaction energy profile; however, qualitatively, the reaction mechanism remains essentially the same. Thus, we would postulate that if the iron ion in the active site were substitutable by nickel and/or cobalt ions enzyme activity would be considerably altered due to high activation barriers.

(salen)MnIII compounds as nonpeptidyl mimics of catalase. Mechanism-based tuning of catalase activity: a theoretical study.

We present the results of the first theoretical investigation of salen-manganese complexes as synthetic catalytic scavengers of hydrogen peroxide molecules that mimic catalase enzymes. Catalase mimics can be used as therapeutic agents against oxidative stress in treatment of many diseases, including Alzheimer's disease, stroke, heart disease, aging, and cancer. A ping-pong mechanism approach has been considered to describe the H2O2 dismutation reaction. The real compounds reacting with a peroxide molecule were utilized in our BP density functional calculations to avoid uncertainties connected with using incomplete models. Part I of the dismutation reaction-converting a peroxide molecule into a water molecule with simultaneous oxidation of the metal atom of the catalyst-can be done quite effectively at the Mn catalytic center. To act as catalytic scavengers of hydrogen peroxide, the oxomanganese salen complexes have to be deoxidized during part II of the dismutation reaction. It has been shown that there are two possible reaction routes for the second part of the dismutation reaction: the top and the side substrate approach routes. Our results suggest that the catalyst could be at least temporarily deactivated (poisoned) in the side approach reaction route due to the formation of a kinetically stable intermediate. Overall, the side approach reaction route for the catalyst recovery is the bottleneck for the whole dismutation process. On the basis of the detailed knowledge of the mode of action of the (salen)MnIII catalase mimics, we suggest and rationalize structural changes of the catalyst that should lead to better therapeutic properties. The available experimental data support our conclusions. Our findings on the reaction dismutation mechanism could be the starting point for further improvement of salen-manganese complexes as synthetic catalytic scavengers of reactive oxygen species.

(Salen)Mn-catalyzed epoxidation of alkenes: a two-zone process with different spin-state channels as suggested by DFT study.

[structure: see text] A novel (two-zone process with different spin-state channels) mechanistic picture for the Jacobsen-Katsuki reaction is presented that provides insight into the still elusive understanding of the epoxidation mechanism. For the first time, we show that the salen moiety of the catalyst can be explicitly involved in the epoxidation process.