Triangle Universities Nuclear Laboratory

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    28232 research outputs found

    Efficient Enumeration and Visualization of Helix-coil Ensembles.

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    Helix-coil models are routinely used to interpret CD data of helical peptides or predict the helicity of naturally-occurring and designed polypeptides. However, a helix-coil model contains significantly more information than mean helicity alone, as it defines the entire ensemble - the equilibrium population of every possible helix-coil configuration - for a given sequence. Many desirable quantities of this ensemble are either not obtained as ensemble averages, or are not available using standard helicity-averaging calculations. Enumeration of the entire ensemble can allow calculation of a wider set of ensemble properties, but the exponential size of the configuration space typically renders this intractable. We present an algorithm that efficiently approximates the helix-coil ensemble to arbitrary accuracy, by sequentially generating a list of the M highest populated configurations in descending order of population. Truncating this list of (configuration, population) pairs at a desired accuracy provides an approximating sub-ensemble. We demonstrate several uses of this approach for providing insight into helix-coil ensembles and folding mechanisms, including landscape visualization

    Annual Research Review: Prenatal opioid exposure - a two-generation approach to conceptualizing neurodevelopmental outcomes.

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    Opioid use during pregnancy impacts the health and well-being of two generations: the pregnant person and the child. The factors that increase risk for opioid use in the adult, as well as those that perpetuate risk for the caregiver and child, oftentimes replicate across generations and may be more likely to affect child neurodevelopment than the opioid exposure itself. In this article, we review the prenatal opioid exposure literature with the perspective that this is not a singular event but an intergenerational cascade of events. We highlight several mechanisms of transmission across generations: biological factors, including genetics and epigenetics and the gut-brain axis; parent-child mechanisms, such as prepregnancy experience of child maltreatment, quality of parenting, infant behaviors, neonatal opioid withdrawal diagnosis, and broader environmental contributors including poverty, violence exposure, stigma, and Child Protective Services involvement. We conclude by describing ways in which intergenerational transmission can be disrupted by early intervention

    KIR polymorphisms modulate peptide-dependent binding to an MHC class I ligand with a Bw6 motif.

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    Molecular interactions between killer immunoglobulin-like receptors (KIRs) and their MHC class I ligands play a central role in the regulation of natural killer (NK) cell responses to viral pathogens and tumors. Here we identify Mamu-A1*00201 (Mamu-A*02), a common MHC class I molecule in the rhesus macaque with a canonical Bw6 motif, as a ligand for Mamu-KIR3DL05. Mamu-A1*00201 tetramers folded with certain SIV peptides, but not others, directly stained primary NK cells and Jurkat cells expressing multiple allotypes of Mamu-KIR3DL05. Differences in binding avidity were associated with polymorphisms in the D0 and D1 domains of Mamu-KIR3DL05, whereas differences in peptide-selectivity mapped to the D1 domain. The reciprocal exchange of the third predicted MHC class I-contact loop of the D1 domain switched the specificity of two Mamu-KIR3DL05 allotypes for different Mamu-A1*00201-peptide complexes. Consistent with the function of an inhibitory KIR, incubation of lymphocytes from Mamu-KIR3DL05(+) macaques with target cells expressing Mamu-A1*00201 suppressed the degranulation of tetramer-positive NK cells. These observations reveal a previously unappreciated role for D1 polymorphisms in determining the selectivity of KIRs for MHC class I-bound peptides, and identify the first functional KIR-MHC class I interaction in the rhesus macaque. The modulation of KIR-MHC class I interactions by viral peptides has important implications to pathogenesis, since it suggests that the immunodeficiency viruses, and potentially other types of viruses and tumors, may acquire changes in epitopes that increase the affinity of certain MHC class I ligands for inhibitory KIRs to prevent the activation of specific NK cell subsets

    Role of C1q complement fixing antibody assay in therapeutic plasma exchange management of pediatric cardiac antibody mediated rejection.

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    Pediatric cardiac transplant patients with antibody-mediated rejection (AMR) often undergo therapeutic plasma exchange (TPE) to remove pathologic donor specific antibodies (DSA). In cases where DSA persist, it is unclear how long TPE should be continued. We report a case of a 17-year-old cardiac transplant patient with AMR where use of a C1q complement fixing antibody assay helped guide TPE cessation. This report adds to the existing literature that highlights the potential clinical significance of C1q antibodies in AMR management

    Are Higher Global Alignment and Proportion Scores Associated With Increased Risks of Mechanical Complications After Adult Spinal Deformity Surgery? An External Validation.

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    BackgroundThe Global Alignment and Proportion (GAP) score, based on pelvic incidence-based proportional parameters, was recently developed to predict mechanical complications after surgery for spinal deformities in adults. However, this score has not been validated in an independent external dataset.Questions/purposesAfter adult spinal deformity surgery, is a higher GAP score associated with (1) an increased risk of mechanical complications, defined as rod fractures, implant-related complications, proximal or distal junctional kyphosis or failure; (2) a higher likelihood of undergoing revision surgery to treat a mechanical complication; and (3) is a lower (more proportioned) GAP score category associated with better validated outcomes scores using the Oswestry Disability Index (ODI), Scoliosis Research Society-22 (SRS-22) and the Short Form-36 questionnaires?MethodsA total of 272 patients who had undergone corrective surgeries for complex spinal deformities were enrolled in the Scoli-RISK-1 prospective trial. Patients were included in this secondary analysis if they fulfilled the original inclusion criteria by Yilgor et al. From the original 272 patients, 14% (39) did not satisfy the radiographic inclusion criteria, the GAP score could not be calculated in 14% (37), and 24% (64) did not have radiographic assessment at postoperative 2 years, leaving 59% (159) for analysis in this review of data from the original trial. A total of 159 patients were included in this study,with a mean age of 58 ± 14 years at the time of surgery. Most patients were female (72%, 115 of 159), the mean number of levels involved in surgery was 12 ± 4, and three-column osteotomy was performed in 76% (120 of 159) of patients. The GAP score was calculated using parameters from early postoperative radiographs (between 3 and 12 weeks) including pelvic incidence, sacral slope, lumbar lordosis, lower arc lordosis and global tilt, which were independently obtained from a computer software based on centralized patient radiographs. The GAP score was categorized as proportional (scores of 0 to 2), moderately disproportional (scores of 3 to 6), or severely disproportional (scores higher than 7 to 13). Receiver operating characteristic area under curve (AUC) was used to assess associations between GAP score and risk of mechanical complications and risk of revision surgery. An AUC of 0.5 to 0.7 was classified as "no or low associative power", 0.7 to 0.9 as "moderate" and greater than 0.9 as "high". We analyzed differences in validated outcome scores between the GAP categories using Wilcoxon rank sum test.ResultsAt a minimum of 2 years' follow-up, a higher GAP score was not associated with increased risks of mechanical complications (AUC = 0.60 [95% CI 0.50 to 0.70]). A higher GAP score was not associated with a higher likelihood of undergoing a revision surgery to treat a mechanical complication (AUC = 0.66 [95% 0.53 to 0.78]). However, a moderately disproportioned GAP score category was associated with better SF-36 physical component summary score (36 ± 10 versus 40 ± 11; p = 0.047), better SF-36 mental component summary score (46 ± 13 versus 51 ± 12; p = 0.01), better SRS-22 total score (3.4 ± 0.8 versus 3.7 ± 0.7, p = 0.02) and better ODI score (35 ± 21 versus 25 ± 20; p = 0.003) than severely disproportioned GAP score category.ConclusionBased on the findings of this external validation study, we found that alignment targets based on the GAP score alone were not associated with increased risks of mechanical complications and mechanical revisions in patients with complex adult spinal disorders. Parameters not included in the original GAP score needed to be considered to reduce the likelihood of mechanical complications.Level of evidenceLevel III, diagnostic study

    On-Site Nurse-Led Cancer Genetics Program Increases Cancer Genetic Testing Completion in Black Veterans.

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    PurposeTelegenetics services can expand access to guideline-recommended cancer genetic testing. However, access is often not distributed equitably to all races and ethnicities. We evaluated the impact of an on-site nurse-led cancer genetics service in a diverse Veterans Affairs Medical Center (VAMC) oncology clinic on likelihood of germline testing (GT) completion.MethodsWe conducted an observational retrospective cohort study of patients who were referred for cancer genetics services at the Philadelphia VAMC between October 1, 2020, and February 28, 2022. We evaluated the association between genetics service (on-site v telegenetics) and likelihood of GT completion in a subcohort of new consults, excluding patients with prior consults and those referred for known history of germline mutations.ResultsA total of 238 Veterans, including 108 (45%) seen on site, were identified for cancer genetics services during the study period, with the majority referred for a personal (65%) or family (26%) history of cancer. In the subcohort of new consults, 121 Veterans (54% self-identified race/ethnicity [SIRE]-Black), including 60 (50%) seen on site, were included in the analysis of germline genetic testing completion. In a univariate analysis, patients who were seen by the on-site genetics service had 3.2-fold higher likelihood of completing GT (relative risk, 3.22; 95% CI, 1.89 to 5.48) compared with the telegenetics service. In multivariable regression analysis, the on-site genetics service was associated with higher likelihood of GT completion, but this association was only statistically significant in SIRE-Black compared with SIRE-White Veterans (adjusted RR, 4.78; 95% CI, 1.53 to 14.96; P P-interaction of race × genetics service = .016).ConclusionAn on-site nurse-led cancer genetics service embedded in a VAMC Oncology practice was associated with higher likelihood of germline genetic testing completion than a telegenetics service among self-identified Black Veterans

    Quantitative cone contrast threshold testing in patients with differing pathophysiological mechanisms causing retinal diseases.

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    BackgroundCone contrast threshold testing (CCT) provides quantitative measurements of color and contrast function to reveal changes in vision quality that are not standard endpoints in clinical trials. We utilize CCT to measure visual function in patients with multiple sclerosis (MS), age-related macular degeneration (AMD), epiretinal membrane (ERM), and retinal vein occlusion (RVO).MethodsRetrospective data was gathered from 237 patients of the Gavin Herbert Eye Institute. Subjects included 17 patients with MS, 45 patients with AMD, 41 patients with ERM, 11 patients with RVO, and 123 healthy controls. Patients underwent the primary measurement outcome, CCT testing, as well as Sloan visual acuity test and spectral domain optical coherence tomography during normal care.ResultsColor and contrast deficits were present in MS patients regardless of history of optic neuritis. AMD with intermediate or worse disease demonstrated reduced CCT scores. All 3 stages of ERM demonstrated cone contrast deficits. Despite restoration of visual acuity, RVO-affected eyes demonstrated poorer CCT performance than unaffected fellow eyes.ConclusionsCCT demonstrates color and contrast deficits for multiple retinal diseases with differing pathophysiology. Further prospective studies of CCT in other disease states and with larger samples sizes is warranted

    A Rule of Life for Home: Equipping Churches to Develop and Engage a Ministry of Faith Formation at Home

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    Many Christians struggle to be significantly formed by their faith through the traditional practices and ministries of the local church. The prevalence and power of competing voices in our culture create exhaustion and fragmentation. Busy schedules, work demands, and extracurricular activities add to this struggle, monopolizing many households’ time and availability. Acknowledging the continual decline in church attendance and engagement across denominational affiliations and traditions, and current research that clearly reveals the necessity of the institutional church for faith development, I will explore some of the ways the church can begin shifting its faith formation practices to help congregants rediscover the deep center of their being in Christ and grow in their faith. Mining the depths of the Christian tradition, I will explore how the church can expand its educational ministries by reinstituting the ancient process of catechesis, which is how the church practiced faith formation for its first three centuries of existence. Arguing that the home is the primary source of faith and values, I will provide the church a method for extending the catechumenate outside the walls of the church by equipping families for the work of faith formation in the home. Drawing from deep within the well of church history, I will examine the core Christian values of early monastic rules that believers must develop in order to participate in the life and mission of Jesus. Utilizing Aristotle’s process for cultivating virtues, I will examine the spiritual disciplines and shared practices of Augustine’s and Benedict’s rules to provide concrete steps for habituating the core Christian values in the lives of believers. As these values are fostered in the homes of believers, Christ can begin to transform their lives from the inside out. What I am proposing is an accessible method for churches to begin equipping families for how to live more fully in the way of Jesus that allows them to experience the abundance (John 10:10) that Christ promised in their homes and wherever they go. </p

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