Evaluation of the Implementation of Low-Low Hospital Beds With Respect to Fall Frequency and Patient Harms: A Retrospective Analysis.

Aim: To identify whether the introduction of low-low hospital beds resulted in changes in the incidence, associated patient harms and event characteristics of bed-related falls where implemented.

Design: This retrospective quality improvement study covered 36 months: 18 months pre-intervention and 18 months post-intervention.

Methods: Our analysis incorporated patient fall data from a hospital in upstate New York.

Chaperone Recycling in Late-Stage Flagellar Assembly.

The flagellum is a sophisticated nanomachine responsible for motility in Gram-negative bacteria. Flagellar assembly is a strictly choreographed process, in which the motor and export gate are formed first, followed by the extracellular propeller structure. Extracellular flagellar components are escorted to the export gate by dedicated molecular chaperones for secretion and self-assembly at the apex of the emerging structure.

Progress toward automated methyl assignments for methyl-TROSY applications.

Methyl-TROSY spectroscopy has extended the reach of solution-state NMR to supra-molecular machineries over 100 kDa in size. Methyl groups are ideal probes for studying structure, dynamics, and protein-protein interactions in quasi-physiological conditions with atomic resolution. Successful implementation of the methodology requires accurate methyl chemical shift assignment, and the task still poses a significant challenge in the field.

2'-O-Methylation can increase the abundance and lifetime of alternative RNA conformational states.

2'-O-Methyl (Nm) is a highly abundant post-transcriptional RNA modification that plays important biological roles through mechanisms that are not entirely understood. There is evidence that Nm can alter the biological activities of RNAs by biasing the ribose sugar pucker equilibrium toward the C3'-endo conformation formed in canonical duplexes. However, little is known about how Nm might more broadly alter the dynamic ensembles of flexible RNAs containing bulges and internal loops.

Structural and Functional Characterization of Sulfonium Carbon-Oxygen Hydrogen Bonding in the Deoxyamino Sugar Methyltransferase TylM1.

The N-methyltransferase TylM1 from Streptomyces fradiae catalyzes the final step in the biosynthesis of the deoxyamino sugar mycaminose, a substituent of the antibiotic tylosin. The high-resolution crystal structure of TylM1 bound to the methyl donor S-adenosylmethionine (AdoMet) illustrates a network of carbon-oxygen (CH···O) hydrogen bonds between the substrate's sulfonium cation and residues within the active site. These interactions include hydrogen bonds between the methyl and methylene groups of the AdoMet sulfonium cation and the hydroxyl groups of Tyr14 and Ser120 in the enzyme.

Water-Mediated Carbon-Oxygen Hydrogen Bonding Facilitates S-Adenosylmethionine Recognition in the Reactivation Domain of Cobalamin-Dependent Methionine Synthase.

The C-terminal domain of cobalamin-dependent methionine synthase (MetH) has an essential role in catalyzing the reactivation of the enzyme following the oxidation of its cobalamin cofactor. This reactivation occurs through reductive methylation of the cobalamin using S-adenosylmethionine (AdoMet) as the methyl donor. Herein, we examine the molecular recognition of AdoMet by the MetH reactivation domain utilizing structural, biochemical, and computational approaches.

Atomic structures of excited state A-T Hoogsteen base pairs in duplex DNA by combining NMR relaxation dispersion, mutagenesis, and chemical shift calculations.

NMR relaxation dispersion studies indicate that in canonical duplex DNA, Watson-Crick base pairs (bps) exist in dynamic equilibrium with short-lived low abundance excited state Hoogsteen bps. N1-methylated adenine (mA) and guanine (mG) are naturally occurring forms of damage that stabilize Hoogsteen bps in duplex DNA. NMR dynamic ensembles of DNA duplexes with mA-T Hoogsteen bps reveal significant changes in sugar pucker and backbone angles in and around the Hoogsteen bp, as well as kinking of the duplex towards the major groove.

Resolving sugar puckers in RNA excited states exposes slow modes of repuckering dynamics.

Recent studies have shown that RNAs exist in dynamic equilibrium with short-lived low-abundance 'excited states' that form by reshuffling base pairs in and around non-canonical motifs. These conformational states are proposed to be rich in non-canonical motifs and to play roles in the folding and regulatory functions of non-coding RNAs but their structure proves difficult to characterize given their transient nature. Here, we describe an approach for determining sugar pucker conformation in RNA excited states through nuclear magnetic resonance measurements of C1΄ and C4΄ rotating frame spin relaxation (R1ρ) in uniformly 13C/15N labeled RNA samples.

Robust IR-based detection of stable and fractionally populated G-C and A-T Hoogsteen base pairs in duplex DNA.

Noncanonical G-C and A-T Hoogsteen base pairs can form in duplex DNA and play roles in recognition, damage repair, and replication. Identifying Hoogsteen base pairs in DNA duplexes remains challenging due to difficulties in resolving syn versus antipurine bases with X-ray crystallography; and size limitations and line broadening can make them difficult to characterize by NMR spectroscopy. Here, we show how infrared (IR) spectroscopy can identify G-C and A-T Hoogsteen base pairs in duplex DNA across a range of different structural contexts.

P-dephased, C-detected REDOR for NMR crystallography at natural isotopic abundance.

Typically, the process of NMR-based structure determination relies on accurately measuring a large number of internuclear distances to serve as restraints for simulated annealing calculations. In solids, the rotational-echo double-resonance (REDOR) experiment is a widely used approach to determine heteronuclear dipolar couplings corresponding to distances usually in the range of 1.5-8Å.

Shortening the HIV-1 TAR RNA Bulge by a Single Nucleotide Preserves Motional Modes over a Broad Range of Time Scales.

Helix-junction-helix (HJH) motifs are flexible building blocks of RNA architecture that help define the orientation and dynamics of helical domains. They are also frequently involved in adaptive recognition of proteins and small molecules and in the formation of tertiary contacts. Here, we use a battery of nuclear magnetic resonance techniques to examine how deleting a single bulge residue (C24) from the human immunodeficiency virus type 1 (HIV-1) transactivation response element (TAR) trinucleotide bulge (U23-C24-U25) affects dynamics over a broad range of time scales.

Amphotericin forms an extramembranous and fungicidal sterol sponge.

For over 50 years, amphotericin has remained the powerful but highly toxic last line of defense in treating life-threatening fungal infections in humans with minimal development of microbial resistance. Understanding how this small molecule kills yeast is thus critical for guiding development of derivatives with an improved therapeutic index and other resistance-refractory antimicrobial agents. In the widely accepted ion channel model for its mechanism of cytocidal action, amphotericin forms aggregates inside lipid bilayers that permeabilize and kill cells.

Using lean techniques to define the platelet (PLT) transfusion process and cost-effectiveness to evaluate PLT dose transfusion strategies.

Background: Platelet (PLT) doses of 1.1 × 10(11), 2.2 × 10(11), and 4.

Effects of granulocyte-colony stimulating factor on chromosome aneuploidy and replication asynchrony in healthy peripheral blood stem cell donors.

As peripheral blood has surpassed bone marrow as a predominant source of stem cells for transplantation, use of the cytokine granulocyte colony-stimulating factor (G-CSF) to mobilize peripheral blood stem cells (PBSCs) is increasing. Issues regarding potential genotoxic effects of even short-term, low-dose G-CSF treatment for the healthy donors have been raised. To address the question of chromosomal instability, we used FISH to evaluate the peripheral blood lymphocytes of 22 PBSC donors and 22 matched controls at 5 time points over a 12-month period.

Molecular determinants of phospholipid synergy in blood clotting.

Many regulatory processes in biology involve reversible association of proteins with membranes. Clotting proteins bind to phosphatidylserine (PS) on cell surfaces, but a clear picture of this interaction has yet to emerge. We present a novel explanation for membrane binding by GLA domains of clotting proteins, supported by biochemical studies, solid-state NMR analyses, and molecular dynamics simulations.

Atomic view of calcium-induced clustering of phosphatidylserine in mixed lipid bilayers.

Membranes play key regulatory roles in biological processes, with bilayer composition exerting marked effects on binding affinities and catalytic activities of a number of membrane-associated proteins. In particular, proteins involved in diverse processes such as vesicle fusion, intracellular signaling cascades, and blood coagulation interact specifically with anionic lipids such as phosphatidylserine (PS) in the presence of Ca(2+) ions. While Ca(2+) is suspected to induce PS clustering in mixed phospholipid bilayers, the detailed structural effects of this ion on anionic lipids are not established.

Backbone 1H, 13C and 15N resonance assignments of the extracellular domain of tissue factor.

Backbone (1)H, (13)C and (15)N resonance assignments are presented for the extracellular domain of tissue factor. Tissue factor is the integral membrane protein that initiates blood coagulation through the formation an enzymatic complex with the plasma serine protease, factor VIIa.

Infrared matrix isolation and theoretical study of the initial intermediates in the reaction of ozone with cis-2-butene.

Matrix isolation studies combined with infrared spectroscopy of the twin jet codeposition of ozone and cis-2-butene into argon matrices have led to the first observation of several early intermediates in this ozonolysis reaction. Specifically, evidence is presented for the formation and identification of the long sought-after Criegee intermediate, as well as confirming evidence for earlier reports of the primary and secondary ozonides. These species were observed after initial twin jet deposition, and grew upon annealing to 35 K.

Protein-phospholipid interactions in blood clotting.

Most steps of the blood clotting cascade require the assembly of a serine protease with its specific regulatory protein on a suitable phospholipid bilayer. Unfortunately, the molecular details of how blood clotting proteins bind to membrane surfaces remain poorly understood, owing to a dearth of techniques for studying protein-membrane interactions at high resolution. Our laboratories are tackling this question using a combination of approaches, including nanoscale membrane bilayers, solid-state NMR, and large-scale molecular dynamics simulations.

Status of blood banking and the blood supply in Afghanistan.

Background: As a result of more than 20 years of war in Afghanistan, its blood supply system has been damaged. We carried out an assessment of that blood supply system to determine the type and extent of assistance needed to increase blood availability and safety.

Study Design And Methods: An assessment tool was developed, daily activities in Afghanistan were observed, and key personnel were interviewed.

Long-term storage of peripheral blood stem cells frozen and stored with a conventional liquid nitrogen technique compared with cells frozen and stored in a mechanical freezer.

Background: Cryopreservation of hematopoietic progenitor cells using liquid nitrogen and controlled-rate freezing requires complex equipment and highly trained staff and is expensive. We compared the liquid nitrogen method with methods using a combination of dimethyl sulfoxide (DMSO) and hydroxyethyl starch (HES) for cryopreservation followed by storage in mechanical freezers.

Study Design And Methods: Peripheral blood stem cells (PBSCs) were collected from normal donors by apheresis and allocated to one of four preservation and storage conditions: 1) 10% DMSO with freezing in liquid nitrogen and storage in liquid nitrogen, 2) 5% DMSO and 6% HES with freezing and storage in a -80 degrees C mechanical freezer, 3) 5% DMSO and 6% HES with freezing in a -80 degrees C mechanical freezer and storage in a -135 degrees C mechanical freezer, or 4) 5% DMSO and 6% HES with freezing and storage both in a 135 degrees C mechanical freezer.