Noncompetitive Determination of Small Analytes by Sandwich-Type Lateral Flow Assay Based on an Aptamer Kissing Complex.

Here, we present the proof-of-concept of a lateral flow assay (LFA) that is capable of detecting small-molecule targets in a noncompetitive manner by deploying a sandwich-type format based on the aptamer kissing complex (AKC) strategy. A fluorescently labeled hairpin aptamer served as the signaling agent, while a specific RNA hairpin grafted onto the strip served as the capture element. The hairpin aptamer switched from an unfolded to a folded form in the presence of the target, resulting in kissing interactions between the loops of the reporter and the capture agents. This design triggered a target-dependent fluorescent signal at the test line. The AKC-based LFA was developed for the detection of adenosine, achieving a detection limit in the micromolar range. The assay revealed the presence of the same analyte in urine. The method also proved effective with another small molecule (theophylline). We believe that the AKC-based LFA approach could overcome many of the shortcomings associated with conventional signal-off methods and competitive processes.

Patient Experiences Navigating Care Coordination For Long COVID: A Qualitative Study.

BACKGROUND: Little is known about how to best evaluate, diagnose, and treat long COVID, which presents challenges for patients as they seek care. OBJECTIVE: Understand experiences of patients as they navigate care for long COVID. DESIGN: Qualitative study involving interviews with patients about topics related to seeking and receiving care for long COVID. PARTICIPANTS: Eligible patients were at least 18 years of age, spoke English, self-identified as functioning well prior to COVID infection, and reported long COVID symptoms continued to impact their lives at 3 months or more after a COVID infection. APPROACH: Patients were recruited from a post-COVID recovery clinic at an academic medical center from August to September 2022. Interviews were audio-recorded, transcribed, and analyzed using thematic analysis. KEY RESULTS: Participants (n=21) reported experiences related to elements of care coordination: access to care, evaluation, treatment, and ongoing care concerns. Some patients noted access to care was facilitated by having providers that listened to and validated their symptoms; other patients reported feeling their access to care was hindered by providers who did not believe or understand their symptoms. Patients reported confusion around how to communicate their symptoms when being evaluated for long COVID, and they expressed frustration with receiving test results that were normal or diagnoses that were not directly attributed to long COVID. Patients acknowledged that clinicians are still learning how to treat long COVID, and they voiced appreciation for providers who are willing to try new treatment approaches. Patients expressed ongoing care concerns, including feeling there is nothing more that can be done, and questioned long-term impacts on their aging and life expectancy. CONCLUSIONS: Our findings shed light on challenges faced by patients with long COVID as they seek care. Healthcare systems and providers should consider these challenges when developing strategies to improve care coordination for patients with long COVID.

Biosensing with DNAzymes.

This article provides a comprehensive review of biosensing with DNAzymes, providing an overview of different sensing applications while highlighting major progress and seminal contributions to the field of portable biosensor devices and point-of-care diagnostics. Specifically, the field of functional nucleic acids is introduced, with a specific focus on DNAzymes. The incorporation of DNAzymes into bioassays is then described, followed by a detailed overview of recent advances in the development of in vivo sensing platforms and portable sensors incorporating DNAzymes for molecular recognition. Finally, a critical perspective on the field, and a summary of where DNAzyme-based devices may make the biggest impact are provided.

Selection and Characterization of an RNA-Cleaving DNAzyme Activated by Legionella pneumophila.

Legionella pneumophila is a deadly bacterial pathogen that has caused numerous Legionnaires' disease outbreaks, where cooling towers were the most common source of exposure. Bacterial culturing is used for L. pneumophila detection, but this method takes approximately 10 days to complete. In this work, an RNA-cleaving fluorogenic DNAzyme, named LP1, was isolated. Extensive characterization revealed that LP1 is reactive with multiple infectious isolates of L. pneumophila but inactive with 25 other common bacterial species. LP1 is likely activated by a protein target, capable of generating a detectable signal in the presence of as few as 10 colony-forming units of L. pneumophila, and able to maintain its activity in cooling tower water from diverse sources. Given that similar DNAzymes have been incorporated into many sensitive assays for bacterial detection, LP1 holds the potential for the development of biosensors for monitoring the contamination of L. pneumophila in exposure sources.

In Vitro Selection of New DNA Aptamers for Human Vascular Endothelial Growth Factor 165.

Two DNA aptamers that bind the heparin-binding domain (HBD) of the human vascular endothelial growth factor 165 (VEGF-165) have been previously reported. Although VEGF-165 is a homodimeric protein and the two aptamers have different sequences and secondary structures, the aptamers appear to occupy the same binding site and cannot form a 2 : 1 aptamer/protein complex, thus making them unsuitable for creating a higher-affinity dimeric DNA aptamer. This has motivated us to conduct a new in vitro selection experiment to search for new VEGF-165-binding DNA aptamers with different properties. We undertook a multistream selection strategy in which the concentration of VEGF-165 was varied significantly. We carried out 11 rounds of selection, and next-generation sequencing was conducted for every round in each stream. From comprehensive sequence analysis, we identified four classes of DNA aptamers, of which two were reported before, but two are new DNA aptamers. One of the new aptamers exhibits a unique property that has never been observed before: it is capable of forming the 2 : 1 aptamer/protein complex with VEGF-165. This work has expanded the repertoire of VEGF-165-binding DNA aptamers and creates a possibility to engineer a higher affinity homodimeric aptamer for VEGF-165.

Highly Sensitive RNA-Cleaving DNAzyme Sensors from Surface-to-Surface Product Enrichment.

The engineering of easy-to-use biosensors with ultra-low detection sensitivity remains a major challenge. Herein, we report a simple approach for creating such sensors through the use of an RNA-cleaving DNAzyme (RcD) and a strategy designed to concentrate its cleavage product significantly. The assay uses micron-sized beads loaded with a target-responsive RcD and a paper strip containing a microzone covered with a DNA oligonucleotide capable of capturing the cleavage product of the RcD through Watson-Crick hybridization. Placing the beads and the paper strip in a target-containing test sample allows the bead-bound RcD molecules to undergo target-induced RNA cleavage, releasing a DNA fragment that is captured by the paper strip. This strategy, though simple, is very effective in achieving high levels of detection sensitivity, being able to enrich the concentration of the cleavage product by three orders of magnitude. It is also compatible with both fluorescence-based and colorimetric reporting mechanisms. This work provides a simple platform for developing ultrasensitive biosensors that take advantage of the widely available RcDs as molecular recognition elements.

Pharmacokinetics and In Vivo Efficacy of Pyrazolopyrimidine, Pyrrolopyrimidine, and 5-Aminopyrazole-4-Carboxamide Bumped Kinase Inhibitors against Toxoplasmosis.

Bumped kinase inhibitors (BKIs) have been shown to be potent inhibitors of Toxoplasma gondii calcium-dependent protein kinase 1. Pyrazolopyrimidine and 5-aminopyrazole-4-carboxamide scaffold-based BKIs are effective in acute and chronic experimental models of toxoplasmosis. Through further exploration of these 2 scaffolds and a new pyrrolopyrimidine scaffold, additional compounds have been identified that are extremely effective against acute experimental toxoplasmosis. The in vivo efficacy of these BKIs demonstrates that the cyclopropyloxynaphthyl, cyclopropyloxyquinoline, and 2-ethoxyquinolin-6-yl substituents are associated with efficacy across scaffolds. In addition, a broad range of plasma concentrations after oral dosing resulted from small structural changes to the BKIs. These select BKIs include anti-Toxoplasma compounds that are effective against acute experimental toxoplasmosis and are not toxic in human cell assays, nor to mice when administered for therapy. The BKIs described here are promising late leads for improving anti-Toxoplasma therapy.

DNAzyme Feedback Amplification: Relaying Molecular Recognition to Exponential DNA Amplification.

Technologies capable of linking DNA amplification to molecular recognition are very desirable for ultrasensitive biosensing applications. We have developed a simple but powerful isothermal DNA amplification method, termed DNAzyme feedback amplification (DFA), that is capable of relaying molecular recognition to exponential DNA amplification. The method incorporates both an RNA-cleaving DNAzyme (RCD) and rolling circle amplification (RCA) carried out by a special DNA polymerase using a circular DNA template. DFA begins with a stimulus-dependent RCA reaction, producing tandemly linked RCDs in long-chain DNA products. These RCDs cleave an RNA-containing DNA sequence to form additional primers that hybridize to the circular DNA molecule, giving rise to DNA assemblies that act as the new inputs for RCA. The RCA reaction and the cleavage event keep on feeding each other autonomously, resulting in exponential growth of repetitive DNA sequences that can be easily detected. This method can be used for the detection of both nucleic acid based targets and non-nucleic acid analytes. In this article, we discuss the conceptual framework of the feedback amplification approach, the essential features of this method as well as remaining challenges and possible solutions.

Analysis of In Vitro Aptamer Selection Parameters.

Nucleic acid aptamers are novel molecular recognition tools that offer many advantages compared to their antibody and peptide-based counterparts. However, challenges associated with in vitro selection, characterization, and validation have limited their wide-spread use in the fields of diagnostics and therapeutics. Here, we extracted detailed information about aptamer selection experiments housed in the Aptamer Base, spanning over two decades, to perform the first parameter analysis of conditions used to identify and isolate aptamers de novo. We used information from 492 published SELEX experiments and studied the relationships between the nucleic acid library, target choice, selection methods, experimental conditions, and the affinity of the resulting aptamer candidates. Our findings highlight that the choice of target and selection template made the largest and most significant impact on the success of a de novo aptamer selection. Our results further emphasize the need for improved documentation and more thorough experimentation of SELEX criteria to determine their correlation with SELEX success.

Comprehensive analytical comparison of strategies used for small molecule aptamer evaluation.

Nucleic acid aptamers are versatile molecular recognition agents that bind to their targets with high selectivity and affinity. The past few years have seen a dramatic increase in aptamer development and interest for diagnostic and therapeutic applications. As the applications for aptamers expand, the need for a more standardized, stringent, and informative characterization and validation methodology increases. Here we performed a comprehensive analysis of a panel of conventional affinity binding assays using a suite of aptamers for the small molecule target ochratoxin A (OTA). Our results highlight inconsistency between conventional affinity assays and the need for multiple characterization strategies. To mitigate some of the challenges revealed in our head-to-head comparison of aptamer binding assays, we further developed and evaluated a set of novel strategies that facilitate efficient screening and characterization of aptamers in solution. Finally, we provide a workflow that permits rapid and robust screening, characterization, and functional verification of aptamers thus improving their development and integration into novel applications.

Trends in Pediatric Attention-Deficit Hyperactive Disorder Diagnoses and Prescription Utilization: 2016 to 2019.

OBJECTIVE: Attention-deficit hyperactive disorder (ADHD) is one of the most common psychiatric disorders among children, with estimated prevalence of 7% to 15% worldwide. The aim of this analysis was to update and summarize trends in diagnosis, demographics, and drug utilization of pediatric patients with ADHD. METHODS: We used the Agency for Health care Research and Quality Medical Expenditure Panel Survey (MEPS), a survey of US individuals, families, their medical providers, and employers, using datasets from 2016 to 2019. The data sources from the MEPS database included the full-year consolidated files, medical conditions files, prescribed-medicines files, and condition-event link files for each year. We summarized trends in the proportion of children, ages 17 years and younger, with a diagnosis of ADHD, demographic information and a prescription for medication known to treat ADHD. In addition, we further stratified ADHD medication use by stimulant/nonstimulant categories. RESULTS: There was a 1.6% and 4.7% absolute increase in children with an ADHD diagnosis and those prescribed ADHD medications, respectively, from 2016 to 2019. Most of these children were male, non-Hispanic, and on public insurance. Of the children prescribed an ADHD medication and concomitant behavioral medications, stimulants-only use was the highest (60%-67%), followed by stimulants/nonstimulants (13%-15%), stimulant/antidepressants (6%-9%), and nonstimulants only (5%-9%). The proportion of patients with ADHD in the high-income and near-poor categories increased by 4% from 2016 to 2019. CONCLUSION: Diagnosis of ADHD among children is trending upward in the United States. Central nervous system stimulants, especially methylphenidate formulations, are the most prescribed ADHD medications for children 17 years and younger.

Transitional care programs for older adults moving from hospital to home in Canada: A systematic review of text and opinion.

BACKGROUND: Investing in transitional care programs is critical for ensuring continuity of health and coordinated care for older adults transitioning across health settings. However, literature delineating the scope of transitional care programs across Canada is limited. The aim of this systematic review of text and opinion is to characterize Canadian transitional care programs for older adults transitioning from hospital to home. METHODS: Following JBI guidelines for systematic review of text and opinion, we conducted a search of Canadian grey literature sources published online between 2016 to 2023. A 3-phase search was undertaken for: 1) Canadian databases and organizational websites; 2) advanced Google search of national sources and news media reports; and 3) advanced Google search of provincial/territorial sources. Two reviewers independently screened sources for eligibility against inclusion criteria. Data were extracted by one reviewer and verified by a second. Textual data were extracted from multiple sources to characterize each transitional care program. RESULTS: Grey literature search produced a total of 17,092 text and opinion sources, identifying 119 transitional care programs in Canada. Model of care was a key characteristic defining the design and delivery of transitional care programs within community (n = 42), hospital (n = 45), and facility-based (n = 32) settings. Programs were characterized by goal, population and eligibility, setting and length of program, intervention and services, and healthcare team members. Patient, caregiver, and health system outcomes were reported for 18 programs. The province of Ontario has the most transitional care programs (n = 84) and reported outcomes, followed by British Columbia (n = 10). CONCLUSIONS: Characterizing transitional care programs is important for informing health services planning and scaling up of transitional care program models across Canada. Recognizing transitional care programs as a core health service is critical to meet the health care needs of older adults at the right time and place. TRIAL REGISTRATION: PROSPERO ID 298821.

A narrative medicine intervention in pediatric residents led to sustained improvements in resident well-being.

BACKGROUND: Burnout in pediatric residents is widespread. Certain factors are associated with decreased burnout, such as empathy, self-compassion, mindfulness, and resilience, while perceived stress is associated with increased burnout. Narrative medicine may reduce burnout by its impact on protective and exacerbating factors and can be an active tool to promote wellness. The objective of this pilot study was to evaluate immediate and delayed benefits of a longitudinal narrative medicine intervention for pediatric residents using qualitative and quantitative measures. MATERIALS AND METHODS: We designed a voluntary longitudinal narrative medicine intervention implemented via Zoom teleconferencing software over five months for pediatric residents at Nationwide Children's Hospital. It consisted of six one-hour long sessions where residents engaged with literature, responded to a writing prompt, and shared their reflections. It was evaluated using open-ended survey questions and established quantitative assessment tools of well-being with validity evidence. Results were compared before the intervention, immediately after, and six months later using one-way ANOVA and multiple linear regression. Qualitative data was analyzed using thematic analysis. RESULTS: Twenty-two (14% of eligible) residents participated in at least one session. After the intervention, the following themes emerged for benefits to resident well-being: the ability to Build Community, have an Outlet for Self-Expression, reap Emotional and Mental Health Benefits, and work on Personal Growth. Benefits were sustained even six months later, which has not been shown previously. While there were significant qualitative findings, between all three time points, there was no change in any quantitative well-being measures. CONCLUSION: Our longitudinal narrative medicine pilot study showed meaningful sustained qualitative benefits, though no quantitative changes, in measured well-being outcomes that have been previously associated with lower resident burnout. While not a panacea, narrative medicine can be a useful strategy for residency programs to improve pediatric resident well-being even after completion of planned interventions.Key MessageWe used a mixed-methods approach to assess the effects of a longitudinal narrative medicine intervention on well-being in pediatric residents.Open-ended responses indicated that residents found utility in and appreciated the intervention and experienced sustained improvements in their mental and emotional health, though the sample size was likely too small to show quantitative changes in well-being measures.Narrative medicine is not a panacea, but it can be a useful tool to provide to pediatric residents to promote sustained improvements in their well-being through the framework of relationship-centered care.

Non-invasive Monitoring of α-Synuclein in Saliva for Parkinson's Disease Using Organic Electrolyte-Gated FET Aptasensor.

Parkinson's disease (PD) currently affects more than 1 million people in the US alone, with nearly 8.5 million suffering from the disease worldwide, as per the World Health Organization. However, there remains no fast, pain-free, and effective method of screening for the disease in the ageing population, which also happens to be the most susceptible to this neurodegenerative disease. αSynuclein (αSyn) is a promising PD biomarker, demonstrating clear delineations between levels of the αSyn monomer and the extent of αSyn aggregation in the saliva of PD patients and healthy controls. In this work, we have demonstrated a laboratory prototype of a soft fluidics integrated organic electrolyte-gated field-effect transistor (OEGFET) aptasensor platform capable of quantifying levels of αSyn aggregation in saliva. The aptasensor relies on a recently reported synthetic aptamer which selectively binds to αSyn monomer as the bio-recognition molecule within the integrated fluidic channel of the biosensor. The produced saliva sensor is label-free, fast, and reusable, demonstrating good selectivity only to the target molecule in its monomer form. The novelty of these devices is the fully isolated organic semiconductor, which extends the shelf life, and the novel fully integrated soft microfluidic channels, which simplify saliva loading and testing. The OEGFET aptasensor has a limit of detection of 10 fg/L for the αSyn monomer in spiked saliva supernatant solutions, with a linear range of 100 fg/L to 10 µg/L. The linear range covers the physiological range of the αSyn monomer in the saliva of PD patients. Our biosensors demonstrate a desirably low limit of detection, an extended linear range, and fully integrated microchannels for saliva sample handling, making them a promising platform for non-invasive point-of-care testing of PD.

"A Widely Applicable Model": Teaching Sarah Manguso's The Two Kinds of Decay Across Institutions.

Many of those teaching at the intersection of medicine and the humanities are siloed within institutional spaces. This essay recounts the teaching of Sarah Manguso's The Two Kinds of Decay to students across different academic contexts and considers what we can learn when we put classrooms in conversation with each other. This essay argues for the value of texts like Manguso's, which explicitly hold the narrating subject and form of illness narrative up for critical examination. The authors call for more collaborative teaching, which has special resonance in the health humanities, where conversations already depend on bridging disciplines and listening to the stories others can tell.

Aptamer-based colorimetric and lateral flow assay approaches for the detection of toxic metal ions, thallium(i) and lead(ii).

Thallium(i) and lead(ii) ions are heavy metals and extremely toxic. These metals are environmental pollutants, posing a severe risk to the environment and human health. In this study, two approaches were examined using aptamer and nanomaterial-based conjugates for thallium and lead detection. The first approach utilized an in-solution adsorption-desorption approach to develop colorimetric aptasensors for the detection of thallium(i) and lead(ii) using gold or silver nanoparticles. The second approach was the development of lateral flow assays, and their performance was tested with thallium (limit of detection is 7.4 µM) and lead ion (limit of detection is 6.6 nM) spiked into real samples. The approaches assessed are rapid, inexpensive, and time efficient with the potential to become the basis for future biosensor devices.

Electrochemical DNAzyme-based biosensors for disease diagnosis.

DNAzyme-based electrochemical biosensors provide exceptional analytical sensitivity and high target recognition specificity for disease diagnosis. This review provides a critical perspective on the fundamental and applied impact of incorporating DNAzymes in the field of electrochemical biosensing. Specifically, we highlight recent advances in creating DNAzyme-based electrochemical biosensors for diagnosing infectious diseases, cancer and regulatory diseases. We also develop an understanding of challenges around translating the research in the field of DNAzyme-based electrochemical biosensors from labs to clinics, followed by a discussion on different strategies that can be applied to enhance the performance of the currently existing technologies to create truly point-of-care electrochemical DNAzyme biosensors.

Consensus Guidelines for the Design and In Vitro Preclinical Efficacy Testing N-of-1 Exon Skipping Antisense Oligonucleotides.

Antisense oligonucleotides (ASOs) can modulate pre-mRNA splicing. This offers therapeutic opportunities for numerous genetic diseases, often in a mutation-specific and sometimes even individual-specific manner. Developing therapeutic ASOs for as few as even a single patient has been shown feasible with the development of Milasen for an individual with Batten disease. Efforts to develop individualized ASOs for patients with different genetic diseases are ongoing globally. The N = 1 Collaborative (N1C) is an umbrella organization dedicated to supporting the nascent field of individualized medicine. N1C recently organized a workshop to discuss and advance standards for the rigorous design and testing of splice-switching ASOs. In this study, we present guidelines resulting from that meeting and the key recommendations: (1) dissemination of standardized experimental designs, (2) use of standardized reference ASOs, and (3) a commitment to data sharing and exchange.