Triphenylphosphine oxide promoting visible-light-driven C-C coupling via desulfurization

Triphenylphosphine oxide (TPPO) and triphenylphosphine (TPP) can form a complex in solution, promoting visible light absorption to trigger electron transfer within the complex and generate radicals. Subsequent radical reactions with thiols enable desulfurization to produce carbon radicals that react with aryl alkenes to yield new C-C bonds. Since ambient oxygen can easily oxidize TPP to TPPO, the reported method requires no explicit addition of a photocatalyst. This work highlights the promise of using TPPO as a catalytic photo-redox mediator in organic synthesis.

Fluorine-thiol displacement probes for acetaminophen's hepatotoxicity

Chemicals possessing reactive electrophiles can denature innate proteins leading to undesired toxicity, and the overdose-induced liver injury by drugs containing electrophiles has been one of the major causes of non-approval and withdraw by the US Food and Drug Administration (FDA). Elucidating the associated proteins could guide the future development of therapeutics to circumvent these drugs' toxicities, but was largely limited by the current probing tools due to the steric hindrance of chemical tags including the common "click chemistry" labels. Taking the widely used non-steroidal anti-inflammatory drug acetaminophen (APAP) as an example, we hereby designed and synthesized an APAP analogue using fluorine as a steric-free label. Cell toxicity studies indicated our analogue has similar activity to the parent drug. This analogue was applied to the mouse hepatocellular proteome together with the corresponding desthiobiotin-SH probe for subsequent fluorine-thiol displacement reactions (FTDRs). This set of probes has enabled the labeling and pull-down of hepatocellular target proteins of the APAP metabolite as validated by Western blotting. Our preliminary validation results supported the interaction of APAP with the thioredoxin protein, which is an important redox protein for normal liver function. These results demonstrated that our probes confer minimal steric perturbation and mimic the compounds of interest, allowing for global profiling of interacting proteins. The fluorine-thiol displacement probing system could emerge as a powerful tool to enable the investigation of drug-protein interactions in complex biological environments.

Unprotected peptide macrocyclization and stapling via a fluorine-thiol displacement reaction

We report the discovery of a facile peptide macrocyclization and stapling strategy based on a fluorine thiol displacement reaction (FTDR), which renders a class of peptide analogues with enhanced stability, affinity, cellular uptake, and inhibition of cancer cells. This approach enabled selective modification of the orthogonal fluoroacetamide side chains in unprotected peptides in the presence of intrinsic cysteines. The identified benzenedimethanethiol linker greatly promoted the alpha helicity of a variety of peptide substrates, as corroborated by molecular dynamics simulations. The cellular uptake of benzenedimethanethiol stapled peptides appeared to be universally enhanced compared to the classic ring-closing metathesis (RCM) stapled peptides. Pilot mechanism studies suggested that the uptake of FTDR-stapled peptides may involve multiple endocytosis pathways in a distinct pattern in comparison to peptides stapled by RCM. Consistent with the improved cell permeability, the FTDR-stapled lead Axin and p53 peptide analogues demonstrated enhanced inhibition of cancer cells over the RCM-stapled analogues and the unstapled peptides.

Strategies capable of stapling unprotected peptides in a straightforward, chemoselective, and clean manner, as well as promoting cellular uptake are of great interest. Here the authors report a peptide macrocyclization and stapling strategy which satisfies those criteria, based on a fluorine thiol displacement reaction.

High-throughput human primary cell-based airway model for evaluating influenza, coronavirus, or other respiratory viruses in vitro

Influenza and other respiratory viruses present a significant threat to public health, national security, and the world economy, and can lead to the emergence of global pandemics such as from COVID-19. A barrier to the development of effective therapeutics is the absence of a robust and predictive preclinical model, with most studies relying on a combination of in vitro screening with immortalized cell lines and low-throughput animal models. Here, we integrate human primary airway epithelial cells into a custom-engineered 96-device platform (PREDICT96-ALI) in which tissues are cultured in an array of microchannel-based culture chambers at an air-liquid interface, in a configuration compatible with high resolution in-situ imaging and real-time sensing. We apply this platform to influenza A virus and coronavirus infections, evaluating viral infection kinetics and antiviral agent dosing across multiple strains and donor populations of human primary cells. Human coronaviruses HCoV-NL63 and SARS-CoV-2 enter host cells via ACE2 and utilize the protease TMPRSS2 for spike protein priming, and we confirm their expression, demonstrate infection across a range of multiplicities of infection, and evaluate the efficacy of camostat mesylate, a known inhibitor of HCoV-NL63 infection. This new capability can be used to address a major gap in the rapid assessment of therapeutic efficacy of small molecules and antiviral agents against influenza and other respiratory viruses including coronaviruses.

Site-specific antibody fragment conjugates for targeted imaging

This work details the use of amber suppression-mediated genetic incorporation of unnatural amino acids (UAAs), specifically p-azido-l-phenylalanine (pAzF) and p-acetyl-l-phenylalanine (pAcF), to develop site-specifically labeled antibody Fab fragments. These antibody fragment conjugates represent a novel class of imaging agents with optimal stability, efficacy, and pharmacological properties, which have demonstrated promising potential for probing and understanding the in vivo bio-distributions of protein targets of interest. This chapter provides general guidelines for preparing these Fab conjugates, and details of follow-up bioassays such as single-agent based positron emission tomography (PET) imaging of immune-checkpoint protein PD-L1, and the use of GCN4-mediated switchable antibody conjugates for near-infrared fluorescent imaging of cancer-related biomarkers.

Application of the Incident Command System to the Hospital Biocontainment Unit Setting

High-consequence pathogens create a unique problem. To provide effective treatment for infected patients while providing safety for the community, a series of 10 high-level isolation units have been created across the country; they are known as Regional Ebola and Special Pathogen Treatment Centers (RESPTCs). The activation of a high-level isolation unit is a highly resource-intensive activity, with effects that ripple across the healthcare system. The incident command system (ICS), a standard tool for command, control, and coordination in domestic emergencies, is a command structure that may be useful in a biocontainment event. A version of this system, the hospital emergency incident command system, provides an adaptable all-hazards approach in healthcare delivery systems. Here we describe its utility in an operational response to safely care for a patient(s) infected with a high-consequence pathogen on a high-level isolation unit. The Johns Hopkins Hospital created a high-level isolation unit to manage the comprehensive and complex needs of patients with high-consequence infectious diseases, including Ebola virus disease. The unique challenges of and opportunities for providing care in this high-level isolation unit led the authors to modify the hospital incident command system model for use during activation. This system has been tested and refined during full-scale functional and tabletop exercises. Lessons learned from the after-action reviews of these exercises led to optimization of the structure and implementation of ICS on the biocontainment unit, including improved job action sheets, designation of physical location of roles, and communication approaches. Overall, the adaptation of ICS for use in the high-level isolation unit setting may be an effective approach to emergency management during an activation.

Simulation of a Spontaneous Vaginal Delivery and Neonatal Resuscitation in a Biocontainment Unit

This article describes a large-scale scenario designed to test the capabilities of a US biocontainment unit to manage a pregnant woman infected with a high-consequence pathogen, and to care for a newborn following labor and spontaneous vaginal delivery. We created and executed a multidisciplinary functional exercise with simulation to test the ability of the Johns Hopkins Hospital biocontainment unit (BCU) to manage a pregnant patient in labor with an unknown respiratory illness and to deliver and stabilize her neonate. The BCU Exercise and Drill Committee established drill objectives and executed the exercise in partnership with the Johns Hopkins Simulation Center in accordance with Homeland Security and Exercise Program guidelines. Exercise objectives were assessed by after-action reporting and objective measurements to detect contamination, using a fluorescent marker to simulate biohazardous fluids that would be encountered in a typical labor scenario. The immediate objectives of the drill were accomplished, with stabilization of the mother and successful delivery and resuscitation of her newborn. There was no evidence of contamination when drill participants were inspected under ultraviolet light at the end of the exercise. Simulation optimizes teamwork, communication, and safety, which are integral to the multidisciplinary care of the maternal-fetal unit infected, or at risk of infection, with a high-consequence pathogen. Lessons learned from this drill regarding patient transportation, safety, and obstetric and neonatal considerations will inform future exercises and protocols and will assist other centers in preparing to care for pregnant patients under containment conditions.

DNA-crowded enzyme complexes with enhanced activities and stabilities

We present a robust and simple method to prepare DNA-crowded enzyme complexes by directly assembling long DNA duplexes on the enzyme surface.

Utilizing Electronic Health Record Information to Optimize Medication Infusion Devices: A Manual Data Integration Approach

Health information technology is increasingly utilized within healthcare delivery systems today. Two examples of this type of technology include the capture of patient-specific information within an electronic health record and intravenous medication infusion devices equipped with dose error reduction software known as drug libraries. Automatic integration of these systems, termed intravenous (IV) interoperability, should serve as the goal toward which all healthcare systems work to maximize patient safety. For institutions lacking IV interoperability, we describe a manual approach of querying the electronic health record to incorporate medication administration information with data from infusion device software to optimize drug library settings. This approach serves to maximize utilization of available information to optimize medication safety provided by drug library software.

Wavefront-guided photorefractive keratectomy in eyes with prior radial keratotomy: a multicenter study

PURPOSE

To investigate the outcomes of wavefront-guided photorefractive keratectomy (WG PRK) using prophylactic mitomycin C (MMC) in eyes that had previously undergone radial keratotomy (RK).

DESIGN

Retrospective, observational, consecutive case series.

PARTICIPANTS

Thirty-two eyes of 27 patients with previous RK that underwent WG PRK with MMC.

METHODS

The records were reviewed of consecutive RK patients whose eyes underwent WG PRK with MMC in 4 centers with postoperative follow-up of 6 months or longer (range, 6-21 months). Eyes were divided into myopic WG PRK and hyperopic WG PRK groups based on their preoperative spherical equivalent (SE). Preoperative best spectacle-corrected visual acuity (BSCVA) was compared with postoperative uncorrected visual acuity (UCVA) and BSCVA to ascertain efficacy and safety. Change in SE and attempted versus achieved SE were evaluated. Incidences of haze and other complications were recorded.

MAIN OUTCOME MEASURES

Uncorrected visual acuity, BSCVA, SE, corneal haze, and other complications.

RESULTS

In the myopic WG PRK group (n = 9), UCVA improved by 3 lines on average (P = 0.015) with UCVA of > or =20/20 in 56% and > or =20/40 in 100% of eyes; 55% were within 0.5 diopter (D), and 100% were within 1 D of attempted refraction. In the hyperopic WG PRK group (n = 23), UCVA improved for 3 lines on average (P<0.001), with UCVA of > or =20/20 in 48% and > or =20/40 in 100% of eyes; 57% were within 0.5 D and 74% were within 1 D of attempted refraction. One eye lost 2 lines of BSCVA as a result of the development of mild to moderate haze, but recovered in 4 months. No eyes lost more than 2 lines of BSCVA. Six eyes (19%; 6/32) experienced the development of haze in the postoperative course, with mild to moderate haze in 1 eye and trace haze in the other 5 eyes. No other complications were noted.

CONCLUSIONS

Wavefront-guided PRK with MMC in eyes with prior RK improved the UCVA significantly and was safe over the short follow-up of this series. Although haze occurred, no eye suffered persistent visual loss of 2 or more lines.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Treatment of Presbyopia With Conductive Keratoplasty??

PURPOSE

To provide 6-month results of a 1-year clinical trial evaluating conductive keratoplasty (CK) for the treatment of presbyopic symptoms in emmetropic and hyperopic eyes.

METHODS

A total of 143 patients with presbyopic symptoms were enrolled in this 1-year United States FDA clinical trial and treated to improve near vision in 1 eye (unilateral treatment). In addition, 33 fellow eyes were treated to improve distance vision (bilateral treatment). For near vision correction, the target refraction was up to -2.0 D in the nondominant eye, and for distance vision correction, 0.0 D. Enrolled patients had a preoperative spherical equivalent of plano to +2.00 D, no more than 0.75 D of refractive astigmatism, and were 40 years of age or older. No retreatments were performed.

RESULTS

Of the eyes treated for near, 77% had uncorrected near vision of J3 or better at 6 months postoperatively. A total of 85% of all patients had binocular distance UCVA of 20/25 or better along with J3 or better near, a combination that represents functional acuity for a presbyope. Sixty-six percent of eyes treated for near had a manifest refractive spherical equivalent (MRSE) within +/- 0.50 D of intended at 6 months. In 89% of eyes, the MRSE changed 0.05 D or less between 3 and 6 months postoperatively. After month 1, the incidence of variables associated with safety was 1% or lower. Seventy-six percent were very satisfied or satisfied with their procedure.

CONCLUSIONS

CK appears to be very safe and effective in producing functional visual acuity in presbyopic eyes up to 6 months following the procedure. Patient satisfaction with the procedure is similar to that of monovision LASIK.

The emergence of a culture that promotes evidence based clinical decision making within an acute care setting

Nursing research programs within acute care hospitals are essential to the development and integration of nursing knowledge, difficult to implement and rarely evaluated. The purpose of this paper is three fold: (1) to describe the development, structures, and processes of a nursing research program within an acute care teaching hospital and (2) to describe selected evaluation outcomes and (3) to discuss future directions.

Clinical Comparison of Cefuroxime Axetil with Cefixime in the Treatment of Acute Bronchitis

Acute bronchitis is the ninth most common outpatient illness seen by physicians in the United States. Oral antibiotic treatment is usually directed empirically against the most common bacterial pathogens associated with acute bronchitis, such as Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Although cefuroxime axetil and cefixime are both approved in the United States for treatment of acute bronchitis, currently they have not undergone direct clinical comparison for this indication. This randomized, investigator-blind, multicenter study was designed to compare the efficacy and safety of 250 mg cefuroxime axetil administered twice daily with that of 400 mg cefixime administered once daily in the treatment of acute bronchitis. Outpatients had to be greater-than-or-equal12 years of age and have signs and symptoms of acute bronchitis to be eligible for this study. Patients were randomly assigned to receive 10 days of oral treatment with either 250 mg cefuroxime axetil taken twice daily or 400 mg cefixime taken once daily. Patients were assessed for both clinical and bacteriologic responses once during treatment (3--5 days) and twice after treatment (1--3 days and 14 days). Bacteriologic assessments were based on sputum specimen cultures obtained pretreatment and posttreatment when possible. Of 465 patients with acute bronchitis who were enrolled in the study, 227 received cefuroxime axetil and 238 received cefixime. Organisms were isolated from the pretreatment sputum specimens in 172 of the 465 (37%) patients, with the primary pathogens being Haemophilus influenzae, Streptococcus pneumoniae, Morazella catarrhalis, and Staphylococcus aureus (30%, 14%, 14%, and 14% of isolates, respectively). A satisfactory clinical outcome (cure or improvement) was achieved in 88% (130 of 148) and 91% (152 of 167) of the clinically evaluable patients who had received cefuroxime axetil or cefixime, respectively (p = 0.36). Regarding the eradication of bacterial pathogens, a satisfactory outcome (cure or presumed cure) was obtained in 89% (47 of 53) and 91% (41 of 45) of bacteriologically evaluated patients who had received cefuroxime axetil or cefixime, respectively (p = 0.75). Treatment with cefixime was associated with a significantly higher incidence of drug-related gastrointestinal adverse events than was treatment with cefuroxime axetil (18% versus 10%, respectively; p = 0.01). This difference primarily reflects a higher incidence of drug-related diarrhea (15% versus 5%, p = 0.001). These results indicated the cefuroxime axetil taken twice daily is as effective as cefixime taken once daily in the treatment of acute bronchitis and that cefuroxime axetil produces fewer gastrointestinal adverse events, particularly diarrhea.

Childbirth education classes: expectant parents' expectations

One hundred clients (43 fathers, 57 mothers), of whom 50 had enrolled in childbirth education classes but had not yet attended and 50 who had attended and were parents of a healthy infant, were surveyed to find out what clients expect to gain from attending childbirth education classes. Responses of preclass and postdelivery male and female clients were compared using content analysis and chi-square statistics. Results suggest that interest followed pregnancy chronology, fathers expected to learn facts, mothers expected to learn coping strategies, and both expected to learn breathing, relaxation, and infant care techniques. Although clients felt that more time should have been spent on the majority of topics, 64% of mothers and 53% of fathers said that the classes had met their expectations.

Complementary methods for evaluating carotid stenosis: a biophysical basis for ocular pulse wave delays

Attempts to noninvasively estimate the significance of carotid arterial stenoses have resulted in a recent technological explosion. Ocular pulse wave timing [oculoplethysmography (OPG) pulse delay] has been strongly promulgated but also criticized on theoretical grounds and for lack of physiologic validation. Audiofrequency analysis of carotid bruits (carotid phonoangiography CPA) has been combined with OPG allegedly to improve accuracy. To evaluate these methods in a controlled model, we studied the effects of graded unilateral stenoses in the canine carotid artery on physiological parameters and associated OPG and CPA recordings. Arterial compliance was calculated from simultaneous diameter and pressure recordings distal to the stenosis. OPG time delay correlated directly with reductions in flow and pressure and with increasing arterial compliance (P less than 0.01). Thus, the delay is caused at least partially by a decreased pulse wave velocity, resulting from the increased compliance distal to stenoses associated with a significant pressure gradient. OPG is most discriminating for stenoses of higher grades. Because bruits arise from flow disturbances that occur even with moderate degrees of stenosis, CPA provides diagnostic information before profound flow reduction occurs. This study illustrates the value of complementary methods for analyzing complex hemodynamic phenomena and provides evidence to support use of the pulse delay concept to diagnose arterial disease.