Hospital Dentistry: The Swiss-Army Knife of Dental Medicine.

Hospital Dentistry is an inclusive synergism of the recognized dental specialties in an emergency/hospital atmosphere. This perspective composition serves to display the breadth of Hospital Dentistry from an observational and creative viewpoint while elucidating the role of the Hospital Dentist in the dynamic large university hospital setting. It calls for increased awareness of the field of Hospital Dentistry and the potential for its specialized role in the future of dental medicine.

A solid-phase extraction method for rapidly determining the adsorption coefficient of pharmaceuticals in sewage sludge.

The partitioning of pharmaceuticals in the environment can be assessed by measuring their adsorption coefficients (Kd) between aqueous and solid phases. Measuring this coefficient in sewage sludge gives an indication of their partitioning behaviour in a wastewater treatment plant and hence contributes to an understanding of their subsequent fate. The regulatory approved method for measuring Kd in sewage sludge is the US Environmental Protection Agency's Office of Prevention, Pesticides and Toxic Substances (OPPTS) guideline 835.

A solid-phase extraction approach for the identification of pharmaceutical-sludge adsorption mechanisms.

It is important to understand the adsorption mechanism of chemicals and active pharmaceutical ingredients (API) on sewage sludge since wastewater treatment plants are the last barrier before the release of these compounds to the environment. Adsorption models were developed considering mostly hydrophobic API-sludge interaction. They have poor predictive ability, especially with ionisable compounds.

Experiences with the OECD 308 transformation test: a human pharmaceutical perspective.

The Organisation for Economic Co-operation and Development (OECD) 308 water-sediment transformation test has been routinely conducted in Phase II Tier A testing of the environmental risk assessment (ERA) for all human pharmaceutical marketing authorization applications in Europe, since finalization of Environmental Medicines Agency (EMA) ERA guidance in June 2006. In addition to the "Ready Biodegradation" test, it is the only transformation test for the aquatic/sediment compartment that supports the classification of the drug substance for its potential persistence in the environment and characterizes the fate of the test material in a water-sediment environment. Presented is an overview of 31 OECD 308 studies conducted by 4 companies with a focus on how pharmaceuticals behave in these water-sediment systems.

Burkholderia xenovorans RcoM(Bx)-1, a transcriptional regulator system for sensing low and persistent levels of carbon monoxide.

The single-component RcoM transcription factor couples an N-terminally bound heme cofactor with a C-terminal "LytTR" DNA-binding domain. Here the RcoM(Bx)-1 protein from Burkholderia xenovorans LB400 was heterologously expressed and then purified in a form with minimal bound CO (~10%) and was found to stably bind this effector with a nanomolar affinity. DNase I protection assays demonstrated that the CO-associated form binds with a micromolar affinity to two ~60-bp DNA regions, each comprised of a novel set of three direct-repeat binding sites spaced 21 bp apart on center.

Multiple operations on the same patient.

Background: Here, we present to practicing spine surgeons and an even broader professional audience a case in which one spine surgeon, operating in his own outpatient surgery facility, performed a staggering number of procedures or "multiple operations on the same patient" (MOSP). In the vacuum of information regarding the multiply operated patient, the authors are without any guidance or even knowledge as to whether or not MOSP is a complete aberration or occurs with some documentable frequency within the medical/surgical profession.

Case Report: The authors report a very extraordinary case of a woman, who, between April 4, 2000, and April 17, 2002, underwent 27 operative procedures on various parts of her spine.

Researching Prescription Drug Misuse among First Nations in Canada: Starting from a Health Promotion Framework.

The intentional misuse of psychotropic drugs is recognized as a significant public health concern in Canada, although there is a lack of empirical research detailing this. Even less research has been documented on the misuse of prescription drugs among First Nations in Canada. In the past, Western biomedical and individual-based approaches to researching Indigenous health have been applied, whereas First Nations' understandings of health are founded on a holistic view of wellbeing.

Identification of Cys94 as the distal ligand to the Fe(III) heme in the transcriptional regulator RcoM-2 from Burkholderia xenovorans.

The CO-responsive transcriptional regulator RcoM from Burkholderia xenovorans (BxRcoM) was recently identified as a Cys(thiolate)-ligated heme protein that undergoes a redox-mediated ligand switch; however, the Cys bound to the Fe(III) heme was not identified. To that end, we generated and purified three Cys-to-Ser variants of BxRcoM-2--C94S, C127S, and C130S--and examined their spectroscopic properties in order to identify the native Cys(thiolate) ligand. Electronic absorption, resonance Raman, and electron paramagnetic resonance (EPR) spectroscopies demonstrate that the C127S and C130S variants, like wild-type BxRcoM-2, bind a six-coordinate low-spin Fe(III) heme using a Cys/His ligation motif.

Complete genome sequence of Rhodospirillum rubrum type strain (S1).

Rhodospirillum rubrum (Esmarch 1887) Molisch 1907 is the type species of the genus Rhodospirillum, which is the type genus of the family Rhodospirillaceae in the class Alphaproteobacteria. The species is of special interest because it is an anoxygenic phototroph that produces extracellular elemental sulfur (instead of oxygen) while harvesting light. It contains one of the most simple photosynthetic systems currently known, lacking light harvesting complex 2.

Ligand responses of Vfr, the virulence factor regulator from Pseudomonas aeruginosa.

Vfr, a transcription factor homologous to the Escherichia coli cyclic AMP (cAMP) receptor protein (CRP), regulates many aspects of virulence in Pseudomonas aeruginosa. Vfr, like CRP, binds to cAMP and then recognizes its target DNA and activates transcription. Here we report that Vfr has important functional differences from CRP in terms of ligand sensing and response.

The poor growth of Rhodospirillum rubrum mutants lacking RubisCO is due to the accumulation of ribulose-1,5-bisphosphate.

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) catalyzes the first step of CO(2) fixation in the Calvin-Benson-Bassham (CBB) cycle. Besides its function in fixing CO(2) to support photoautotrophic growth, the CBB cycle is also important under photoheterotrophic growth conditions in purple nonsulfur photosynthetic bacteria. It has been assumed that the poor photoheterotrophic growth of RubisCO-deficient strains was due to the accumulation of excess intracellular reductant, which implied that the CBB cycle is important for maintaining the redox balance under these conditions.

Sustaining N2-dependent growth in the presence of CO.

Low levels of carbon monoxide inhibit the N(2)-dependent growth of Rhodospirillum rubrum unless the ∼100-residue CowN protein is expressed. Expression requires the CO-responsive regulator RcoM and is maximal in cells grown in the presence of CO and a poor nitrogen source, consistent with the role of CowN in N(2) fixation.

Elimination of Rubisco alters the regulation of nitrogenase activity and increases hydrogen production in Rhodospirillum rubrum.

Nitrogenase not only reduces atmospheric nitrogen to ammonia, but also reduces protons to hydrogen (H(2)). The nitrogenase system is the primary means of H(2) production under photosynthetic and nitrogen-limiting conditions in many photosynthetic bacteria, including Rhodospirillum rubrum. The efficiency of this biological H(2) production largely depends on the nitrogenase enzyme and the availability of ATP and electrons in the cell.

Mutagenesis and functional characterization of the four domains of GlnD, a bifunctional nitrogen sensor protein.

GlnD is a bifunctional uridylyltransferase/uridylyl-removing enzyme (UTase/UR) and is believed to be the primary sensor of nitrogen status in the cell by sensing the level of glutamine in enteric bacteria. It plays an important role in nitrogen assimilation and metabolism by reversibly regulating the modification of P(II) protein; P(II) in turn regulates a variety of other proteins. GlnD appears to have four distinct domains: an N-terminal nucleotidyltransferase (NT) domain; a central HD domain, named after conserved histidine and aspartate residues; and two C-terminal ACT domains, named after three of the allosterically regulated enzymes in which this domain is found.

"Where are my teeth?" A case of unnoticed ingestion of a dislodged fixed partial denture.

What are the dangers of swallowing foreign bodies of dental origin? How do we recognize when a patient has actually swallowed a dental appliance? How far should we pursue the retrieval of the appliance? We report a case of a patient with unnoticed ingestion of a dislodged fixed partial denture while undergoing general anesthesia and review the literature on dangers of swallowing foreign bodies of dental origin. Anesthesiologists should understand the dangers and recognize this complication when it happens, so that appropriate treatment can be pursued if necessary.

Cyclic di-GMP allosterically inhibits the CRP-like protein (Clp) of Xanthomonas axonopodis pv. citri.

The protein Clp from Xanthomonas axonopodis pv. citri regulates pathogenesis and is a member of the CRP (cyclic AMP receptor protein) superfamily. We show that unlike the DNA-binding activity of other members of this family, the DNA-binding activity of Clp is allosterically inhibited by its effector and that cyclic di-GMP serves as that effector at physiological concentrations.

Effect of perturbation of ATP level on the activity and regulation of nitrogenase in Rhodospirillum rubrum.

Nitrogenase activity in Rhodospirillum rubrum and in some other photosynthetic bacteria is regulated in part by the availability of light. This regulation is through a posttranslational modification system that is itself regulated by P(II) homologs in the cell. P(II) is one of the most broadly distributed regulatory proteins in nature and directly or indirectly senses nitrogen and carbon signals in the cell.

Identification and functional characterization of NifA variants that are independent of GlnB activation in the photosynthetic bacterium Rhodospirillum rubrum.

The activity of NifA, the transcriptional activator of the nitrogen fixation (nif) gene, is tightly regulated in response to ammonium and oxygen. However, the mechanisms for the regulation of NifA activity are quite different among various nitrogen-fixing bacteria. Unlike the well-studied NifL-NifA regulatory systems in Klebsiella pneumoniae and Azotobacter vinelandii, in Rhodospirillum rubrum NifA is activated by a direct protein-protein interaction with the uridylylated form of GlnB, which in turn causes a conformational change in NifA.

The transcription regulator RcoM-2 from Burkholderia xenovorans is a cysteine-ligated hemoprotein that undergoes a redox-mediated ligand switch.

Spectroscopic characterization of the newly discovered heme-PAS domain sensor protein BxRcoM-2 reveals that this protein undergoes redox-dependent ligand switching and CO- and NO-induced ligand displacement. The aerobic bacterium Burkholderia xenovorans expresses two homologous heme-containing proteins that promote CO-dependent transcription in vivo. These regulators of CO metabolism, BxRcoM-1 and BxRcoM-2, are gas-responsive heme-PAS domain proteins like mammalian neuronal PAS domain protein 2 (NPAS2) and the direct oxygen sensor from Escherichia coli ( EcDos).

Two-state allosteric modeling suggests protein equilibrium as an integral component for cyclic AMP (cAMP) specificity in the cAMP receptor protein of Escherichia coli.

Activation of the cAMP receptor protein (CRP) from Escherichia coli is highly specific to its allosteric ligand, cAMP. Ligands such as adenosine and cGMP, which are structurally similar to cAMP, fail to activate wild-type CRP. However, several cAMP-independent CRP variants (termed CRP*) exist that can be further activated by both adenosine and cGMP, as well as by cAMP.

RcoM: a new single-component transcriptional regulator of CO metabolism in bacteria.

Genomic analysis suggested the existence of a CO-sensing bacterial transcriptional regulator that couples an N-terminal PAS fold domain to a C-terminal DNA-binding LytTR domain. UV/visible-light spectral analyses of heterologously expressed, purified full-length proteins indicated that they contained a hexacoordinated b-type heme moiety that avidly binds CO and NO. Studies of protein variants strongly suggested that the PAS domain residues His74 and Met104 serve as the heme Fe(II) axial ligands, with displacement of Met104 upon binding of the gaseous effectors.

Mechanism of the CO-sensing heme protein CooA: new insights from the truncated heme domain and UVRR spectroscopy.

The bacterial CO-sensing heme protein CooA activates expression of genes whose products perform CO-metabolism by binding its target DNA in response to CO binding. The required conformational change has been proposed to result from CO-induced displacement of the heme and of the adjacent C-helix, which connects the sensory and DNA-binding domains. Support for this proposal comes from UV Resonance Raman (UVRR) spectroscopy, which reveals a more hydrophobic environment for the C-helix residue Trp110 when CO binds.