Responding to In-hospital Cardiac Arrests During Times of System-wide Strain: A Code Refresher Training.

Background: Pandemic conditions of system-wide strain are associated with increased rates of in-hospital cardiac arrest (IHCA). During normal times, medical-surgical nurses may forget cardiopulmonary resuscitation (CPR) skills as soon as 3 months after training, leaving them unprepared and anxious about managing cardiac arrests. During pandemic surges, heightened anxiety can also impact concentration and confidence.

Continuous Capnography Reduces the Incidence of Opioid-Induced Respiratory Rescue by Hospital Rapid Resuscitation Team.

Objective: The aim of this study was to determine the impact of end tidal carbon dioxide or capnography monitoring in patients requiring patient-controlled analgesia (PCA) on the incidence of opioid-induced respiratory depression (OIRD) in the setting of rapid response.

Methods: A retrospective analysis was conducted in an urban tertiary care facility on the incidence of OIRD in the setting of rapid response as defined by a positive response to naloxone from January 2012 to December 2015. In March 2013, continuous capnography monitoring was implemented for all patients using PCA.

A Framework of Care in Multiple Sclerosis, Part 2: Symptomatic Care and Beyond.

The Consortium of Multiple Sclerosis Centers (CMSC) convened a Framework Taskforce composed of a multidisciplinary group of clinicians and researchers to examine and evaluate the current models of care in multiple sclerosis (MS). The methodology of this project included analysis of a needs assessment survey and an extensive literature review. The outcome of this work is a two-part continuing education series of articles.

How accurate are resting energy expenditure prediction equations in obese trauma and burn patients?

Background: While the prevalence of obesity continues to increase in our society, outdated resting energy expenditure (REE) prediction equations may overpredict energy requirements in obese patients. Accurate feeding is essential since overfeeding has been demonstrated to adversely affect outcomes.

Objectives: The first objective was to compare REE calculated by prediction equations to the measured REE in obese trauma and burn patients.

Unusual origins of isotope effects in enzyme-catalysed reactions.

High hydrostatic pressure is a neglected tool for probing the origins of isotope effects. In chemical reactions, normal primary deuterium isotope effects (DIEs) arising solely from differences in zero point energies are unaffected by pressure; but some anomalous isotope effects in which hydrogen tunnelling is suspected are partially suppressed. In some enzymatic reactions, high pressure completely suppresses the DIE.

Effect of pressure on a heavy-atom isotope effect of yeast alcohol dehydrogenase.

Hydrostatic pressure causes a monophasic decrease in the (13)C primary isotope effect expressed on the oxidation of benzyl alcohol by yeast alcohol dehydrogenase. The primary isotope effect was measured by the competitive method, using whole-molecule mass spectrometry. The effect is, therefore, an expression of isotopic discrimination on the kinetic parameter V/K, which measures substrate capture.

Capillary electrophoretic analysis of phosphorus species in clandestine methamphetamine laboratory samples.

The clandestine manufacture of methamphetamine is a spreading epidemic. Manufacturing methods are constantly changing, necessitating the implementation of new analytical tools to identify materials from these labs. Characterization of phosphate, phosphite, and hypophosphite ions is necessary to distinguish the various phosphorus-iodine manufacturing methods that are popular methods for reducing pseudoephedrine to methamphetamine.

Unusual solute protection against pressure inactivation of yeast alcohol dehydrogenase.

A 3:1 combination of sucrose and glycine provides significantly greater protection against pressure-induced inactivation of yeast alcohol dehydrogenase than either solute alone. Trehalose, alone, gives much greater protection than sucrose alone, but not so in combination with glycine. These are striking new findings that cannot be accounted for by current theories of protein stabilization.

Effects of trehalose on pressure-induced inactivation of yeast alcohol dehydrogenase.

Isozymes of yeast alcohol dehydrogenase are slowly denatured at moderate hydrostatic pressures (<3 kbar). The time courses for inactivation are biphasic and both phases of both isozymes are protected by trehalose. ADH-I is slightly more barostable than ADH-II which is opposite to their thermostabilities.

Effect of pressure on nucleotide binding to yeast alcohol dehydrogenase.

Binding of reduced nicotinamide adenine dinucleotide to yeast alcohol dehydrogenase results in a hypsochromic shift of its absorbance maximum at 340 nm. Application of high hydrostatic pressure to the enzyme-nucleotide complex returns the absorbance maximum to longer wavelengths. This pressure-dependent bathochromic shift validates one of two assignments on the effects of pressure on the kinetics of the enzymatic oxidation of benzyl alcohol, namely the protein-ligand conformational change of the capturing form of enzyme.

Addressing the specialized needs of younger adults with multiple sclerosis.

Multiple sclerosis (MS), a chronic, variable, and often disabling disease of the central nervous system, presents a myriad of challenges to people battling the disease and to their family. The diagnosis of MS usually comes when men and women are in their 20s, 30s, and 40s-a time of life when they are completing their education, embarking on their careers, and establishing families. No one can predict at the time of diagnosis the severity, the course, or the progression that the disease will take.

Effects of pressure on deuterium isotope effects of yeast alcohol dehydrogenase using alternative substrates.

Hydrostatic pressure causes biphasic effects on the oxidation of alcohols by yeast alcohol dehydrogenase as expressed on the kinetic parameter V/K which measures substrate capture. Moderate pressure increases capture by activating hydride transfer, whose transition-state must therefore have a smaller volume than the free alcohol plus the capturing form of enzyme, with DeltaV(double dagger)=-30 mL mol(-1) for isopropanol. A comparison of these effects with those on the oxidation of deutero-isopropanol generates a monophasic decrease in the intrinsic isotope effect; therefore, the volume of activation for the transition-state of deuteride transfer must be even more negative, by 7.

Pressure stability of proteins at their isoelectric points.

Yeast alcohol dehydrogenase is slowly denatured at moderate hydrostatic pressure (t(1/2) approximately equals 30 min at 2 kbar and pH 7). The extent of denaturation is pH dependent with maximal stability near the isoelectric point of the protein, pH = 5.4.

Kinetic mechanism of the GCN5-related chromosomal aminoglycoside acetyltransferase AAC(6')-Ii from Enterococcus faecium: evidence of dimer subunit cooperativity.

The aminoglycoside 6'-N-acetyltransferase AAC(6')-Ii from Enterococcus faecium is an important microbial resistance determinant and a member of the GCN5-related N-acetyltransferase (GNAT) superfamily. We report here the further characterization of this enzyme in terms of the kinetic mechanism of acetyl transfer and identification of rate-contributing step(s) in catalysis, as well as investigations into the binding of both acetyl-CoA and aminoglycoside substrates to the AAC(6')-Ii dimer. Product and dead-end inhibition studies revealed that AAC(6')-Ii follows an ordered bi-bi ternary complex mechanism with acetyl-CoA binding first followed by antibiotic.

Effects of high pressure on enzymatic activity.

Effects of high pressure on enzymatic reactions are poised to revolutionize enzyme kinetics. The reason for this is that experimental designs are at hand to separate effects on equilibria between reactant states from effects on catalytic transition states and both yield new information. The first of the former runs contrary to Pauling's hypothesis that substrates are bound more tightly in the transition state, while the latter penetrates the 'black box' of catalysis, the stabilized transition state itself, and returns a precise measure of a physical parameter, deltaV.

Follow the protons: a low-barrier hydrogen bond unifies the mechanisms of the aspartic proteases.

Seven proton transfers in five steps participate in a catalytic turnover of an aspartic protease. The Rosetta Stone for elucidating their role is a low-barrier hydrogen bond that holds the two aspartic carboxyls in a coplanar conformation. The proton of this bond shuttles between oxygens during chemical steps via hydrogen tunneling, unlike in previous proposals where it was transferred to substrate.

Uses of isotope effects in the study of enzymes.

There have been few recent additions to the technical methods employed in the study of isotope effects, notable exceptions being the use of high pressure as an experimental variable and the measurement of heavy-atom isotope effects on maximal velocities using continuous-flow techniques. Most of the innovations are in the realm of new experimental designs that allow the asking of new questions. These designs include the use of isotope effects to: determine kinetic mechanisms, distinguish between changes in enzymatic activity and loss of active enzyme, distinguish between reactant-state origins and transition-state origins and quantify hydrogen tunneling, separate and quantify multiple origins of solvent isotope effects, distinguish between concerted and stepwise chemical mechanisms, characterize bond order changes in ligand binding, distinguish different pathways of inhibitor binding, and estimate intrinsic isotope effects.

Effect of pressure on deuterium isotope effects of formate dehydrogenase.

High pressure causes biphasic effects on the oxidation of formate by yeast formate dehydrogenase as expressed on the kinetic parameter V/K, which measures substrate capture. Moderate pressure increases capture by accelerating hydride transfer. The transition state for hydride transfer has a smaller volume than the free formate plus the capturing form of enzyme, with DeltaV(double dagger) = -9.

Effects of high pressure on solvent isotope effects of yeast alcohol dehydrogenase.

The effect of pressure on the capture of a substrate alcohol by yeast alcohol dehydrogenase is biphasic. Solvent isotope effects accompany both phases and are expressed differently at different pressures. These differences allow the extraction of an inverse intrinsic kinetic solvent isotope effect of 1.

Effect of pressure on deuterium isotope effects of yeast alcohol dehydrogenase: evidence for mechanical models of catalysis.

Moderate pressure accelerates hydride transfer catalyzed by yeast alcohol dehydrogenase, indicative of a large negative volume of activation [Cho and Northrop (1999) Biochemistry 38, 7470-7475]. A comparison of the effects of pressure on the oxidation of normal versus dideuteriobenzyl alcohol generates a monophasic decrease in the intrinsic isotope effect; therefore, the volume of activation for the transition-state of deuteride transfer must be even more negative, by 10.4 mL/mol.

Effects of pressure on the kinetics of capture by yeast alcohol dehydrogenase.

High pressure causes biphasic effects on the oxidation of benzyl alcohol by yeast alcohol dehydrogenase as expressed in the kinetic parameter V/K which measures substrate capture. Moderate pressure increases the rate of capture of benzyl alcohol by activating the hydride transfer step. This means that the transition state for hydride transfer has a smaller volume than the free alcohol plus the capturing form of enzyme, with a DeltaV of -39 +/- 1 mL/mol, a value that is relatively large.