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Thomas R Russell

Publications and source records attributed to Thomas R Russell.

16 recordsLinked to original sources
PubMed2006

American College of Surgeons remains committed to patient safety.

Since 1913 the American College of Surgeons has addressed patient safety as a top priority, so they are pleased to contribute this article offering the College's perspective on this critical subject. More specifically, this piece reviews the College's perennial efforts to ensure surgeons and hospitals access to scientifically verifiable standards, availability of effective quality improvement tools, and a better understanding of errors in care. Additionally, they examine the cultural changes required within surgery and provide an overview of the College's recent initiatives in research, accreditation, and education.

Education, Medical↗
PubMed2005

Annals of surgery.

Explore the source record for details and available documents.

Career Choice↗
PubMed2004

Aminobacter aminovorans NADH:flavin oxidoreductase His140: a highly conserved residue critical for NADH binding and utilization.

Homodimeric FRD(Aa) Class I is an NADH:flavin oxidoreductase from Aminobacter aminovorans. It is unusual because it contains an FMN cofactor but utilizes a sequential-ordered kinetic mechanism. Because little is known about NADH-specific flavin reductases in general and FRD(Aa) in particular, this study aimed to further explore FRD(Aa) by identifying the functionalities of a key residue. A sequence alignment of FRD(Aa) with several known and hypothetical flavoproteins in the same subfamily reveals within the flavin reductase active-site domain a conserved GDH motif, which is believed to be responsible for the enzyme and NADH interaction. Mutation of the His140 in this GDH motif to alanine reduced FRD(Aa) activity to <3%. An ultrafiltration assay and fluorescence quenching demonstrated that H140A FRD(Aa) binds FMN in the same 1:1 stoichiometric ratio as the wild-type enzyme, but with slightly weakened affinity (K(d) = 0.9 microM). Anaerobic stopped-flow studies were carried out using both the native and mutated FRD(Aa). Similar to the native enzyme, H140A FRD(Aa) was also able to reduce the FMN cofactor by NADH although much less efficiently. Kinetic analysis of anaerobic reduction measurements indicated that the His140 residue of FRD(Aa) was essential to NADH binding, as well as important for the reduction of the FMN cofactor. For the native enzyme, the cofactor reduction was followed by at least one slower step in the catalytic pathway.

Alphaproteobacteria↗
PubMed2004

Kinetic mechanism and quaternary structure of Aminobacter aminovorans NADH:flavin oxidoreductase: an unusual flavin reductase with bound flavin.

The homodimeric NADH:flavin oxidoreductase from Aminobacter aminovorans is an NADH-specific flavin reductase herein designated FRD(Aa). FRD(Aa) was characterized with respect to purification yields, thermal stability, isoelectric point, molar absorption coefficient, and effects of phosphate buffer strength and pH on activity. Evidence from this work favors the classification of FRD(Aa) as a flavin cofactor-utilizing class I flavin reductase. The isolated native FRD(Aa) contained about 0.5 bound riboflavin-5'-phosphate (FMN) per enzyme monomer, but one bound flavin cofactor per monomer was obtainable in the presence of excess FMN or riboflavin. In addition, FRD(Aa) holoenzyme also utilized FMN, riboflavin, or FAD as a substrate. Steady-state kinetic results of substrate titrations, dead-end inhibition by AMP and lumichrome, and product inhibition by NAD(+) indicated an ordered sequential mechanism with NADH as the first binding substrate and reduced FMN as the first leaving product. This is contrary to the ping-pong mechanism shown by other class I flavin reductases. The FMN bound to the native FRD(Aa) can be fully reduced by NADH and subsequently reoxidized by oxygen. No NADH binding was detected using 90 microM FRD(Aa) apoenzyme and 300 microM NADH. All results favor the interpretation that the bound FMN was a cofactor rather than a substrate. It is highly unusual that a flavin reductase using a sequential mechanism would require a flavin cofactor to facilitate redox exchange between NADH and a flavin substrate. FRD(Aa) exhibited a monomer-dimer equilibrium with a K(d) of 2.7 microM. Similarities and differences between FRD(Aa) and certain flavin reductases are discussed.

Alphaproteobacteria↗
PubMed2002

Interleukin-1beta activity and collagen synthesis in human dental pulp fibroblasts.

Immunopathologic reactions play a significant role in inflammatory diseases of dental pulp. Interleukin-1beta (IL-1beta) is recognized as a key player in mediating cellular immune response. In this study, we measured the content of IL-1beta and its effect on collagen synthesis in cultures of fibroblasts derived from healthy and diseased dental pulps. We found that diseased pulp fibroblasts contain 2.5-fold greater amounts of IL-1beta and synthesized 80% greater amounts of collagen compared with healthy pulp fibroblasts. However, exogenous IL-1beta failed to stimulate collagen synthesis by diseased fibroblasts, whereas collagen synthesis by healthy pulp fibroblasts was stimulated by more than 2-fold. These observations imply that pulp disease induces abnormalities associated with fibroblast response toward IL-1beta.

Analysis of Variance↗