Analytical characterization of full, intermediate, and empty AAV capsids.

Manufacturing of recombinant adeno-associated virus (AAV) vectors produces three types of capsids: full, intermediate, and empty. While there are different opinions about the impact of intermediate and empty capsids on safety and efficacy of AAV products, they are generally considered impurities because they are not the intended fully intact vector product. The presence of these impurities could impact product efficacy due to potential competition with fully packaged AAVs for cellular transduction, as well as have potential implications to patient safety due to increased capsid load during dosing. To determine the impact of intermediate capsids on potency, an AAV preparation was separated into fractions enriched for full, intermediate, or empty capsids. Using a matrix of in vitro (infectivity, gene expression, biological activity) and in vivo potency assays to determine potency as a function of capsid content, our results indicate that while intermediate capsids contribute to the vector genome titer of the product and are equally as infectious as full capsids, they do not contribute to the potency of the AAV product. This study confirms the criticality of reducing and controlling the level of intermediate capsids to ensure a more efficacious AAV product.

Measuring LEND Core Competencies Using Trainee Follow-Up Surveys.

OBJECTIVES: Measuring the value-added impact of Leadership Education in Neurodevelopmental Disabilities and Related Disorders (LEND) training on trainees' leadership and career trajectories is necessary to understand program efficacy. In the current study, we leveraged an existing ex post facto design to develop and test a new measure of LEND competencies and compare outcomes of LEND trainees and comparison peers. METHODS: We developed the LEND Outcomes Follow-Up Survey using a multi-step, mixed methods process. A series of focus groups and consultations with key stakeholders identified eight important LEND leadership outcomes: (1) interdisciplinary work; (2) advocacy; (3) intersectional approach; (4) systems perspective; (5) life course perspective; (6) leadership; (7) engagement with maternal and child health populations; and (8) research experience. We developed and piloted this novel survey to measure these LEND leadership outcomes. We used data collected from this novel measure and an existing survey that is used nationally by LEND, to compare the outcomes of 43 LEND trainees and 30 comparison peers at two years post completion of LEND training. RESULTS: We found that, compared to comparison peers, LEND trainees: (1) worked with a greater number of disciplines; (2) were more likely to be engaged in advocacy; (3) were more likely to utilize a systems perspective in their work; (4) were more likely to work with maternal and child health populations; and (5) were more likely to have experience conducting research. CONCLUSIONS: Our findings suggested that LEND training improves LEND leadership outcomes at two years post-completion of LEND training.

A model to evaluate interprofessional training effectiveness: feasibility and five-year outcomes of a multi-site prospective cohort study.

OBJECTIVES: Assessing the impact of interdisciplinary training programs is highly desirable and needed. However, there are currently no established methods to prospectively assess long-term outcomes of trainees compared to individuals who did not receive training. Our objective was to test the feasibility of a longitudinal, prospective cohort design to evaluate training outcomes, and to use this method to evaluate Leadership Education in Neurodevelopmental Disabilities and Related Disorders (LEND) training outcomes. METHODS: LEND trainees were matched to comparison peers and followed annually for up to five years using a pre-existing outcomes survey. We assessed study feasibility using recruitment and retention data over five years. We then looked at preliminary efficacy of LEND training in LEND trainees compared to comparison peers using the pre-existing outcomes survey. RESULTS: Overall, 68.3% of eligible trainees participated in the Outcomes Study across five years, and 66.0% were matched to comparison peers. On average, 84.4% of LEND trainees and 79.9% of comparison peers completed the outcomes survey annually. Attrition was low at 0.9% for LEND trainees and 2.6% for comparison peers over five years. LEND training demonstrated preliminary efficacy in promoting leadership development: LEND trainees began their careers engaged in more leadership activities than comparison peers, and the rate of growth in their participation in leadership activities was greater. CONCLUSIONS: The design used to assess outcomes is a feasible approach that can be widely used to assess training program outcomes. Analyses suggest that LEND training is efficacious in increasing involvement in leadership activities over time after graduation.

Resolution of mixed site DNA complexes with dimer-forming minor-groove binders by using electrospray ionization mass spectrometry: compound structure and DNA sequence effects.

Small-molecule targeting of the DNA minor groove is a promising approach to modulate genomic processes necessary for normal cellular function. For instance, dicationic diamindines, a well-known class of minor groove binding compounds, have been shown to inhibit interactions of transcription factors binding to genomic DNA. The applications of these compounds could be significantly expanded if we understand sequence-specific recognition of DNA better and could use the information to design more sequence-specific compounds. Aside from polyamides, minor groove binders typically recognize DNA at A-tract or alternating AT base pair sites. Targeting sites with GC base pairs, referred to here as mixed base pair sequences, is much more difficult than those rich in AT base pairs. Compound 1 is the first dicationic diamidine reported to recognize a mixed base pair site. It binds in the minor groove of ATGA sequences as a dimer with positive cooperativity. Due to the well-characterized behavior of 1 with ATGA and AT rich sequences, it provides a paradigm for understanding the elements that are key for recognition of mixed sequence sites. Electrospray ionization mass spectrometry (ESI-MS) is a powerful method to screen DNA complexes formed by analogues of 1 for specific recognition. We also report a novel approach to determine patterns of recognition by 1 for cognate ATGA and ATGA-mutant sequences. We found that functional group modifications and mutating the DNA target site significantly affect binding and stacking, respectively. Both compound conformation and DNA sequence directionality are crucial for recognition.

Mixed up minor groove binders: Convincing A·T specific compounds to recognize a G·C base pair.

DNA minor-groove-binding compounds have limited biological applications, in part due to problems with sequence specificity that cause off-target effects. A model to enhance specificity has been developed with the goal of preparing compounds that bind to two AT sites separated by G·C base pairs. Compounds of interest were probed using thermal melting, circular dichroism, mass spectrometry, biosensor-SPR, and molecular modeling methods. A new minor groove binder that can strongly and specifically recognize a single G·C base pair with flanking AT sequences has been prepared. This multi-site DNA recognition mode offers novel design principles to recognize entirely new DNA motifs.

May the Best Molecule Win: Competition ESI Mass Spectrometry.

Electrospray ionization mass spectrometry has become invaluable in the characterization of macromolecular biological systems such as nucleic acids and proteins. Recent advances in the field of mass spectrometry and the soft conditions characteristic of electrospray ionization allow for the investigation of non-covalent interactions among large biomolecules and ligands. Modulation of genetic processes through the use of small molecule inhibitors with the DNA minor groove is gaining attention as a potential therapeutic approach. In this review, we discuss the development of a competition method using electrospray ionization mass spectrometry to probe the interactions of multiple DNA sequences with libraries of minor groove binding molecules. Such an approach acts as a high-throughput screening method to determine important information including the stoichiometry, binding mode, cooperativity, and relative binding affinity. In addition to small molecule-DNA complexes, we highlight other applications in which competition mass spectrometry has been used. A competitive approach to simultaneously investigate complex interactions promises to be a powerful tool in the discovery of small molecule inhibitors with high specificity and for specific, important DNA sequences.

A novel approach using electrospray ionization mass spectrometry to study competitive binding of small molecules with mixed DNA sequences.

Minor groove binding compounds have been shown to induce changes in global DNA conformation, allosterically inhibiting DNA-protein interactions necessary for transcriptional processes. Many minor groove binders are specific for AT base pairs but have little preference over alternating AT or A-tract sequences. Few compounds, other than polyamides, show selectivity for mixed sequences with AT and GC base pairs. Electrospray ionization mass spectrometry (ESI-MS) can provide insight on the stoichiometry and relative affinities in minor groove recognition of different DNA sequences with a library of minor groove binders. A goal in our current research is to develop new compounds that recognize mixed sequences of DNA. In an effort to optimize screening for compounds that target mixed AT and GC base pair sequences of DNA, ESI-MS was used to study the competitive binding of compounds with a mixed set of DNA sequences. The method identified preferred binding sites, relative affinities, and concentration-dependent binding stoichiometry for the minor groove binding compounds netropsin and DB75 with AT-rich sequences and DB293 with ATGA and AT sites.

Probing the general time scale question of boronic acid binding with sugars in aqueous solution at physiological pH.

The boronic acid group is widely used in chemosensor design due to its ability to reversibly bind diol-containing compounds. The thermodynamic properties of the boronic acid-diol binding process have been investigated extensively. However, there are few studies of the kinetic properties of such binding processes. In this report, stopped-flow method was used for the first time to study the kinetic properties of the binding between three model arylboronic acids, 4-, 5-, and 8-isoquinolinylboronic acids, and various sugars. With all the boronic acid-diol pairs examined, reactions were complete within seconds. The k(on) values with various sugars follow the order of D-fructose>D-tagatose>D-mannose>D-glucose. This trend tracks the thermodynamic binding affinities for these sugars and demonstrates that the 'on' rate is the key factor determining the binding constant.

The Effects of Gamma Irradiation on Chemical Biomarker Recovery from Mixed Chemical/Biological Threat Exposure Specimens.

BACKGROUND: Irradiative sterilization of clinical specimens prior to chemical laboratory testing provides a way to not only sterilize pathogens and ensure laboratorian safety but also preserve sample volume and maintain compatibility with quantitative chemical diagnostic protocols. Since the compatibility of clinical biomarkers with gamma irradiation is not well characterized, a subset of diagnostic biomarkers ranging in molecular size, concentration, and clinical matrix was analyzed to determine recovery following gamma irradiation. METHODS: Sample irradiation of previously characterized quality control materials (QCs) at 5 Mrad was carried out at the Gamma Cell Irradiation Facility at the Centers for Disease Control and Prevention (CDC) in Atlanta, GA. Following irradiation, the QCs were analyzed alongside non-irradiated QCs to determine analyte recovery between dosed and control samples. RESULTS: Biomarkers for exposure to abrin, ricin, and organophosphorus nerve agents (OPNAs) were analyzed for their stability following gamma irradiation. The diagnostic biomarkers included adducts to butyrylcholinesterase, abrine, and ricinine, respectively, and were recovered at over 90% of their initial concentration. CONCLUSIONS: The results from this pilot study support the implementation of an irradiative sterilization protocol for possible mixed-exposure samples containing both chemical and biological threat agents (mixed CBTs). Furthermore, irradiative sterilization significantly reduces a laboratorian's risk of infection from exposure to an infectious agent without compromising chemical diagnostic testing integrity, particularly for diagnostic assays in which the chemical analyte has been shown to be fully conserved following a 5 Mrad irradiative dose.

Selective Serotonin Reuptake Inhibitor Monotherapy for Anxiety Disorders in Children and Adolescents with Autism Spectrum Disorder: A Chart Review.

Objective: Anxiety disorders are one of the most commonly co-occurring psychiatric diagnoses in youth with autism spectrum disorder (ASD), with a frequency ranging from 22% to 84%. Methods: We conducted a chart review of 29 children and adolescents with ASD who had been treated with selective serotonin reuptake inhibitor (SSRI) monotherapy for an anxiety disorder for at least 2 months. Subsequent chart reviews were conducted for the first follow-up visit within 2-6 months (M = 4.2 months) and the visit closest to 9 months posttreatment (ranging from 7 to 12 months; M = 10.5 months). The presence of adverse events (AEs) was examined, and a consensus Clinical Global Impressions Improvement (CGI-I) score was determined. Results: Fifty-five percent of patients were given a CGI-I of "improved" or "very much improved" at the 9-month follow-up. Four patients discontinued treatment owing to AEs. Other reported AEs not leading to discontinuation included vivid dreaming, increased emotional lability, and irritability. Responders included a number of patients who had failed previous SSRI trials. Conclusions: This study suggests that SSRI treatment should be considered for individuals with ASD and anxiety disorders, even if prior SSRI trials have been unsuccessful.

Quantification of hypoglycin A and methylenecyclopropylglycine in human plasma by HPLC-MS/MS.

Hypoglycin A (HGA) and methylenecyclopropylglycine (MCPG) are naturally-occurring amino acids known to cause hypoglycemia and encephalopathy. Exposure to one or both toxins through the ingestion of common soapberry (Sapindaceae) fruits are documented in illness outbreaks throughout the world. Jamaican Vomiting Sickness (JVS) and seasonal pasture myopathy (SPM, horses) are linked to HGA exposure from unripe ackee fruit and box elder seeds, respectively. Acute toxic encephalopathy is linked to HGA and MCPG exposures from litchi fruit. HGA and MCPG are found in several fruits within the soapberry family and are known to cause severe hypoglycemia, seizures, and death. HGA has been directly quantified in horse blood in SPM cases and in human gastric juice in JVS cases. This work presents a new diagnostic assay capable of simultaneous quantification of HGA and MCPG in human plasma, and it can be used to detect patients with toxicity from soapberry fruits. The assay presented herein is the first quantitative method for MCPG in blood matrices.