Direct Heterocycle C-H Alkenylation via Dual Catalysis Using a Palladacycle Precatalyst: Multifactor Optimization and Scope Exploration Enabled by High-Throughput Experimentation.

One of the major challenges in developing catalytic methods for C-C bond formation is the identification of generally applicable reaction conditions, particularly if multiple substrate structural classes are involved. Pd-catalyzed direct arylation reactions are powerful transformations that enable direct functionalization of C-H bonds; however, the corresponding direct alkenylation reactions, using vinyl (pseudo) halide electrophiles, are less well developed. Inspired by process development efforts toward GSK3368715, an investigational active pharmaceutical ingredient, we report that a Pd(II) palladacycle derived from tri-tert-butylphosphine and Pd(OAc)2 is an effective single-component precatalyst for a variety of direct alkenylation reactions. High-throughput experimentation identified optimal solvent/base combinations for a variety of HetAr-H substrate classes undergoing C-H activation without the need for cocatalysts or stoichiometric silver bases (e.g., Ag2CO3). We propose this reaction proceeds via a dual cooperative catalytic mechanism, where in situ-generated Pd(0) supports a canonical Pd(0)/(II) cross-coupling cycle and the palladacycle effects C-H activation via CMD in a redox-neutral cycle. In all, 192 substrate combinations were tested with a hit rate of approximately 40% and 24 isolated examples. Importantly, this method was applied to prepare a key intermediate in the synthesis of GSK3368715 on multigram scale.

Evaluation of dexmedetomidine withdrawal in critically ill adults.

BACKGROUND: Dexmedetomidine (DEX) withdrawal syndrome has been reported in the pediatric population, but literature describing DEX withdrawal in critically ill adults is limited. The purpose of this study was to determine the incidence of DEX withdrawal in adult patients and to identify factors associated with DEX withdrawal syndrome. METHODS: A retrospective chart review was performed in the adult intensive care units of two tertiary medical centers. Eligible patients were at least 18 years of age and received DEX for 24 h or more. Patients were excluded if they presented with a primary neurologic diagnosis, had a history of substance abuse, or received any other α2-agonists 24 h before discontinuation of DEX. The primary outcome was the percentage of patients who developed withdrawal as defined by the presence of two or more symptoms (tachycardia, hypertension, vomiting, agitation) within the 24 h following DEX discontinuation. RESULTS: Of the 165 patients included, 50 patients experienced withdrawal (30.3%), lasting a median of two days. The incidence of withdrawal was higher in surgical (40%) compared to medical (28%) or cardiac (32%) patients (p = 0.004). Median duration of infusion was 52.5 h (interquartile range [IQR], 37.8 to 102.8) in the withdrawal group and 52 h (IQR, 41 to 87) in the non-withdrawal group (p = 0.887). Median DEX dose was 0.56 µg/kg/h (IQR, 0.39 to 0.83) in the withdrawal group and 0.48 µg/kg/h (0.36 to 0.65) in the non-withdrawal group (p = 0.12). Weaning did not reduce the incidence of withdrawal as compared to abrupt discontinuation (p = 0.68). The withdrawal group was more likely to have concomitantly discontinued opioids (54% vs 12.2%) and benzodiazepines (36% vs 0%) at the time of DEX discontinuation compared to the non-withdrawal group (p = 0.004). CONCLUSION: Development of DEX-associated withdrawal occurred in approximately 30% of adult patients, comparable to rates reported in pediatric literature. There appeared to be no correlation between dose, exposure, and weaning in the occurrence of withdrawal, but concomitant discontinuation of opioids or benzodiazepines as well as ICU admission type could highlight cases requiring closer monitoring.

Basic statistics: A research primer for low- and middle-income countries.

Statistics can be used to describe data or make inferences about populations using samples. Median values (the 50th percentile) better represent central tendency of data samples than means (averages), particularly when data have extreme values. Errors resulting from use of inferential statistics when using classical hypothesis testing include type I (finding a difference between groups when one does not exist) and type II (failure to find a true difference) errors. Confounding variables (those that vary with both the dependent variable and independent variable) may lead to spurious associations. Classical hypothesis testing and reporting only p-values tends to be greatly overused and overemphasized. Confidence intervals provide a range of values for a sample within a certain probability (commonly 95%). Confidence intervals can thus describe sizes of likely differences between samples, and are much more clinically useful information than only p-values. Before doing a study, the required sample size should be calculated to assess study feasibility. Doing so requires specification of the acceptable risk of type I and II errors and the size of the lowest clinically meaningful difference between groups.

Prospective Observational Evaluation of Sedation and Pain Management Guideline Adherence Across New Jersey Intensive Care Units.

BACKGROUND: The practice guidelines for the management of pain, agitation, and delirium (PAD) from the Society of Critical Care Medicine shifted from primarily focusing on the treatment of anxiety in 2002 to the treatment of pain in 2013. OBJECTIVE: This prospective, observational, multicenter study aimed to assess the degree of practice adherence to the PAD guidelines for ventilated patients in New Jersey intensive care units (ICUs). METHODS: Pharmacist investigators at 8 centers designated 4 days at least 10 days apart to evaluate all patients on mechanical ventilation. The primary outcomes included adherence to 4 guideline recommendations: treatment of pain before sedation, use of nonnarcotic analgesic medications, use of nonbenzodiazepine sedative medications, and use of goal-directed sedation. RESULTS: Of 138 patients evaluated, 50% had a primary medical diagnosis (as opposed to surgical, cardiac, or neurological diagnosis), and the median Sequential Organ Failure Assessment (SOFA) score was 7. Pain was treated prior to administration of sedatives in 55.4% of subjects, with fentanyl being the primary analgesic used. In addition, 19% received no analgesia, and 11.5% received nonopioid analgesia. Sedative agents were administered to 87 subjects (48 nonbenzodiazepine and 39 benzodiazepine). Of those receiving benzodiazepines, 22 received intermittent bolus regimens and 16 received continuous infusions, of which 5 were for another indication besides sedation. Validated scales measuring the degree of sedation were completed at least once in 56 (81.6%) patients receiving sedatives. CONCLUSIONS: Current sedation practices suggest that integration of evidence-based PAD guidelines across New Jersey adult ICUs is inconsistent despite pharmacist involvement.

Resistance to Second-Generation HIV-1 Maturation Inhibitors.

A betulinic acid-based compound, bevirimat (BVM), inhibits HIV-1 maturation by blocking a late step in protease-mediated Gag processing: the cleavage of the capsid-spacer peptide 1 (CA-SP1) intermediate to mature CA. Previous studies showed that mutations conferring resistance to BVM cluster around the CA-SP1 cleavage site. Single amino acid polymorphisms in the SP1 region of Gag and the C terminus of CA reduced HIV-1 susceptibility to BVM, leading to the discontinuation of BVM's clinical development. We recently reported a series of "second-generation" BVM analogs that display markedly improved potency and breadth of activity relative to the parent molecule. Here, we demonstrate that viral clones bearing BVM resistance mutations near the C terminus of CA are potently inhibited by second-generation BVM analogs. We performed de novo selection experiments to identify mutations that confer resistance to these novel compounds. Selection experiments with subtype B HIV-1 identified an Ala-to-Val mutation at SP1 residue 1 and a Pro-to-Ala mutation at CA residue 157 within the major homology region (MHR). In selection experiments with subtype C HIV-1, we identified mutations at CA residue 230 (CA-V230M) and SP1 residue 1 (SP1-A1V), residue 5 (SP1-S5N), and residue 10 (SP1-G10R). The positions at which resistance mutations arose are highly conserved across multiple subtypes of HIV-1. We demonstrate that the mutations confer modest to high-level maturation inhibitor resistance. In most cases, resistance was not associated with a detectable increase in the kinetics of CA-SP1 processing. These results identify mutations that confer resistance to second-generation maturation inhibitors and provide novel insights into the mechanism of resistance.IMPORTANCE HIV-1 maturation inhibitors are a class of small-molecule compounds that block a late step in the viral protease-mediated processing of the Gag polyprotein precursor, the viral protein responsible for the formation of virus particles. The first-in-class HIV-1 maturation inhibitor bevirimat was highly effective in blocking HIV-1 replication, but its activity was compromised by naturally occurring sequence polymorphisms within Gag. Recently developed bevirimat analogs, referred to as "second-generation" maturation inhibitors, overcome this issue. To understand more about how these second-generation compounds block HIV-1 maturation, here we selected for HIV-1 mutants that are resistant to these compounds. Selections were performed in the context of two different subtypes of HIV-1. We identified a small set of mutations at highly conserved positions within the capsid and spacer peptide 1 domains of Gag that confer resistance. Identification and analysis of these maturation inhibitor-resistant mutants provide insights into the mechanisms of resistance to these compounds.

µImpact of a nursing-driven sedation protocol with criteria for infusion initiation in the surgical intensive care unit.

PURPOSE: Analgesia and sedation protocols (ASPs) reduce duration of mechanical ventilation (MV) in the medical intensive care unit (ICU), but data in the surgical ICU (SICU) are limited. The objective of this study was to determine the impact of a nursing-driven ASP with criteria for infusion initiation in the SICU. MATERIALS AND METHODS: A single-center, retrospective study compared ventilator-free days at day 28 from start of MV (VFD28) before and after ASP implementation. Secondary endpoints included cumulative opioid and sedative requirements, level of sedation, incidence of delirium, SICU and hospital length of stay. RESULTS: One hundred thirty two patients were included (66 per group). The protocol group had greater VFD28 compared to the control group (21 vs. 14.5 days, p = .04). Lower rates of benzodiazepine (42.4% vs. 84.8%, p < .001) and opioid (24.2 vs. 78.8, p < .001) infusion use occurred in the protocol group, resulting in lower cumulative doses per ventilator-day through day 7. The protocol group had more documented sedation scores within target range. There were no differences in ICU delirium, SICU or hospital length of stay. CONCLUSIONS: A nursing-driven ASP with criteria for infusion initiation in mechanically-ventilated SICU patients may increase ventilator-free time, maintain patients at the target sedation goal, and reduce opioid and benzodiazepine utilization.

Case Reports of Aripiprazole Causing False-Positive Urine Amphetamine Drug Screens in Children.

Urine drug screens (UDSs) are used to identify the presence of certain medications. One limitation of UDSs is the potential for false-positive results caused by cross-reactivity with other substances. Amphetamines have an extensive list of cross-reacting medications. The literature contains reports of false-positive amphetamine UDSs with multiple antidepressants and antipsychotics. We present 2 cases of presumed false-positive UDSs for amphetamines after ingestion of aripiprazole. Case 1 was a 16-month-old girl who accidently ingested 15 to 45 mg of aripiprazole. She was lethargic and ataxic at home with 1 episode of vomiting containing no identifiable tablets. She remained sluggish with periods of irritability and was admitted for observation. UDS on 2 consecutive days came back positive for amphetamines. Case 2 was of a 20-month-old girl who was brought into the hospital after accidental ingestion of an unknown quantity of her father's medications which included aripiprazole. UDS on the first day of admission came back positive only for amphetamines. Confirmatory testing with gas chromatography-mass spectrometry (GC-MS) on the blood and urine samples were also performed for both patients on presentation to detect amphetamines and were subsequently negative. Both patients returned to baseline and were discharged from the hospital. To our knowledge, these cases represent the first reports of false-positive amphetamine urine drug tests with aripiprazole. In both cases, aripiprazole was the drug with the highest likelihood of causing the positive amphetamine screen. The implications of these false-positives include the possibility of unnecessary treatment and monitoring of patients.

Conformationally constrained functional peptide monolayers for the controlled display of bioactive carbohydrate ligands.

In this study, we employed thiolated peptides of the conformationally constrained, strongly helicogenic α-aminoisobutyric acid (Aib) residue to prepare self-assembled monolayers (SAMs) on gold surfaces. Electrochemistry and infrared reflection absorption spectroscopy support the formation of very well packed Aib-peptide SAMs. The immobilized peptides retain their helical structure, and the resulting SAMs are stabilized by a network of intermolecular H bonds involving the NH groups adjacent to the Au surface. Binary SAMs containing a synthetically defined glycosylated mannose-functionalized Aib-peptide as the second component display similar features, thereby providing reproducible substrates suitable for the controlled display of bioactive carbohydrate ligands. The efficiency of such Aib-based SAMs as a biomolecular recognition platform was evidenced by examining the mannose-concanavalin A interaction via surface plasmon resonance biosensing.

Biofunctional paper via the covalent modification of cellulose.

Paper-based analytical devices are the subject of growing interest for the development of low-cost point-of-care diagnostics, environmental monitoring technologies, and research tools for limited-resource settings. However, there are limited chemistries available for the conjugation of biomolecules to cellulose for use in biomedical applications. Herein, divinyl sulfone (DVS) chemistry was demonstrated to immobilize small molecules, proteins, and DNA covalently onto the hydroxyl groups of cellulose membranes through nucleophilic addition. Assays on modified cellulose using protein-carbohydrate and protein-glycoprotein interactions as well as oligonucleotide hybridization showed that the membrane's bioactivity was specific, dose-dependent, and stable over a long period of time. The use of an inkjet printer to form patterns of biomolecules on DVS-activated cellulose illustrates the adaptability of the DVS functionalization technique to pattern sophisticated designs, with potential applications in cellulose-based lateral flow devices.

An organophosphonate strategy for functionalizing silicon photonic biosensors.

Silicon photonic microring resonators have established their potential for label-free and low-cost biosensing applications. However, the long-term performance of this optical sensing platform requires robust surface modification and biofunctionalization. Herein, we demonstrate a conjugation strategy based on an organophosphonate surface coating and vinyl sulfone linker to biofunctionalize silicon resonators for biomolecular sensing. To validate this method, a series of glycans, including carbohydrates and glycoconjugates, were immobilized on divinyl sulfone (DVS)/organophosphonate-modified microrings and used to characterize carbohydrate-protein and norovirus particle interactions. This biofunctional platform was able to orthogonally detect multiple specific carbohydrate-protein interactions simultaneously. Additionally, the platform was capable of reproducible binding after multiple regenerations by high-salt, high-pH, or low-pH solutions and after 1 month storage in ambient conditions. This remarkable stability and durability of the organophosphonate immobilization strategy will facilitate the application of silicon microring resonators in various sensing conditions, prolong their lifetime, and minimize the cost for storage and delivery; these characteristics are requisite for developing biosensors for point-of-care and distributed diagnostics and other biomedical applications. In addition, the platform demonstrated its ability to characterize carbohydrate-mediated host-virus interactions, providing a facile method for discovering new antiviral agents to prevent infectious disease.

gem-Dimethyl 4-pentenyl glycosides: novel glycosylating agents and anomeric protecting groups.

Two classes of gem-dimethyl 4-n-pentenyl glycosides (i.e., C2-series and C3-series) have been prepared and studied in both the glycosylation and hydrolysis manifolds utilizing NBS as the sole stoichiometric activator. These novel glycosylating agents, which are analogues of Fraser-Reid's 4-n-pentenyl glycosyl donors, show increased reactivity in side-by-side studies by virtue of the gem-dimethyl effect.

Adenosine A1 antagonism attenuates beta-adrenergic-resistant sudden hypoxic cardiac insufficiency.

OBJECTIVES: In states such as hypoxia, shock, and cardiac arrest, compromised systemic oxygenation or perfusion appears to induce cardiac insufficiency that can be resistant to beta-adrenergic drugs. Elevated levels of adenosine may mediate such beta-adrenergic-resistant cardiac insufficiency via the adenosine A(1) receptor (A(1)AdoR). The objective of this study was to test the hypothesis that selective A(1)AdoR antagonism attenuates hypoxic cardiac insufficiency more efficaciously than beta(1)-adrenergic agonism or nonselective adenosine antagonism. METHODS: Rats were paralyzed and ventilated to a pCO(2) level of 35-40 mm Hg. Ten minutes before hypoxia (inspired o(2) concentration = 5%), rats were treated intravenously with one of the following: 0.1 mg/kg BG-9719 (n = 9), 10 mg/kg NPC-205 (n = 10; BG-9719 and NPC-205 are selective A(1)AdoR antagonists, with durations of action of 30-60 minutes and 60-90 minutes, respectively), 10 mg/kg aminophylline (n = 12), 5 microg/kg/min dobutamine (n = 11), or control solutions. These drug doses maximized survival duration in dose-response studies. RESULTS: Before hypoxia, cardiac work was increased more by aminophylline and dobutamine than by BG-9719. Mean (+/-SEM) duration of survival (in minutes) after hypoxia increased from <13 (control solutions) to 13.8 (+/-1.4) (dobutamine), 20.0 (+/-1.6) (aminophylline), 31.7 (+/-4.6) (BG-9719), and 40.5 (+/-7.5) (NPC-205) (p < 0.0001). Heart rate and dP/dt decreased rapidly after hypoxia, but decreases were attenuated with BG-9719 and NPC-205 compared with dobutamine (p < 0.05) and tended toward attenuation with aminophylline. CONCLUSIONS: BG-9719 and NPC-205 improved survival duration, heart rate, and left ventricular contractility during hypoxia more efficaciously than dobutamine and possibly aminophylline. Selective A(1)AdoR antagonists warrant further study as alternatives to beta-adrenergic agonists in hypoxia, shock, and cardiac arrest, in which compromised systemic perfusion or oxygenation impairs cardiac output.

Adenosine A1 antagonism attenuates atropine-resistant hypoxic bradycardia in rats.

OBJECTIVES: To test the following hypotheses: Hypoxia induces bradycardia and hemodynamic compromise that are resistant to atropine but responsive to selective antagonism of the adenosine A1 receptor (A1AdoR). The mechanism for such attenuation is independent of the vagus nerve. METHODS: Ten minutes after sham or actual bilateral cervical vagotomy, paralyzed ventilated rats were made hypoxic (5% fractional inspired oxygen, continued until death). Five minutes after beginning hypoxia, intravenous treatment with BG-9719, a selective A1AdoR antagonist (0.1 mg/kg); atropine (0.1 mg/kg); BG-9719 vehicle; or saline was initiated. These drug doses were based on pilot studies. Of the eight treatment groups (eight possible combinations of vagotomy status and drug/vehicle treatment), n = 8 in all except nonvagotomized, vehicle-treated rats (where n = 7). RESULTS: Heart rate and left ventricular contractility decreased rapidly with hypoxia. Atropine had minimal effects in prolonging survival (from mean +/- SEM of 15.5 +/- 2.1 minutes to 20.2 +/- 2.5 minutes, p = 0.94) and attenuating posthypoxic decreases in heart rate (p = 0.89) and contractility (p = 0.83) compared with saline. BG-9719 prolonged survival, however, from 14.4 +/- 1.9 minutes (with vehicle treatment) to 37.2 +/- 6.8 minutes (p < 0.001). Survival, heart rate, and contractility were preserved with BG-9719 compared with atropine and vehicle (p < 0.05, all comparisons). Vagotomy prevented the effects of BG-9719 on survival prolongation (p = 0.003), heart rate (p = 0.01), and contractility (p < 0.001) but did not affect those outcomes in saline-treated rats. CONCLUSIONS: Survival, heart rate, and contractility were better preserved with BG-9719 than atropine. A1AdoR selective antagonism, possibly because of its multiple mechanisms for attenuating hypoxic cardiac insufficiency, resulted in better hemodynamic and clinical outcomes. That attenuation seems to have a component of vagal mediation.

De novo design of biomimetic antimicrobial polymers.

The design of polymers and oligomers that mimic the complex structures and remarkable biological properties of proteins is an important endeavor with both fundamental and practical implications. Recently, a number of nonnatural peptides with designed sequences have been elaborated to provide biologically active structures; in particular, facially amphiphilic peptides built from beta-amino acids have been shown to mimic both the structures as well as the biological function of natural antimicrobial peptides such as magainins and cecropins. However, these natural peptides as well as their beta-peptide analogues are expensive to prepare and difficult to produce on a large scale, limiting their potential use to certain pharmaceutical applications. We therefore have designed a series of facially amphiphilic arylamide polymers that capture the physical and biological properties of this class of antimicrobial peptides, but are easy to prepare from inexpensive monomers. The design process was aided by molecular calculations with density functional theory-computed torsional potentials. This new class of amphiphilic polymers may be applied in situations where inexpensive antimicrobial agents are required.