Publications by authors named "Derek Pappas"

Acute lymphoblastic leukemia (ALL) in children is associated with a distinct neonatal cytokine profile. The basis of this neonatal immune phenotype is unknown but potentially related to maternal-fetal immune receptor interactions. We conducted a case-control study of 226 case child-mother pairs and 404 control child-mother pairs to evaluate the role of interaction between HLA genotypes in the offspring and maternal killer immunoglobulin-like receptor (KIR) genotypes in the etiology of childhood ALL, while considering potential mediation by neonatal cytokines and the immune-modulating enzyme arginase-II (ARG-II).

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Human milk optimizes gut microbial richness and diversity, and is critical for proper immune development. Research has shown differing microbial composition based on geographic location, providing evidence that diverse biospecimen data is needed when studying human bacterial communities. Yet, limited research describes human milk and infant gut microbial communities in Africa.

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Bridging ImmunoGenomic Data-Analysis Workflow Gaps (BIGDAWG) is an integrated data-analysis pipeline designed for the standardized analysis of highly-polymorphic genetic data, specifically for the HLA and KIR genetic systems. Most modern genetic analysis programs are designed for the analysis of single nucleotide polymorphisms, but the highly polymorphic nature of HLA and KIR data require specialized methods of data analysis. BIGDAWG performs case-control data analyses of highly polymorphic genotype data characteristic of the HLA and KIR loci.

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The development of a California-based induced pluripotent stem cell (iPSC) bank based on human leukocyte antigen (HLA) haplotype matching represents a significant challenge and a valuable opportunity for the advancement of regenerative medicine. However, previously published models of iPSC banks have neither addressed the admixed nature of populations like that of California nor evaluated the benefit to the population as a whole. We developed a new model for evaluating an iPSC haplobank based on demographic and immunogenetic characteristics reflecting California.

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Multiple lines of evidence support an immunologic basis and genetic disposition for the development of age-related macular degeneration (AMD). Comprehensive human leukocyte antigens (HLA) class II typing at four loci (DRB1, DQA1, DQB1, and DPB1) was assessed using next generation sequencing methods and tested for association with age-related macular degeneration (AMD) in a case-control study of 456 AMD cases and 499 controls from the population-based Study of Osteoporotic Fractures (SOF) cohort. No statistically significant associations were identified for any of the class II loci and a previously identified association between DRB1*13:01 was not replicated in this dataset.

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High-resolution haplotype frequency estimations and descriptive metrics are becoming increasingly popular for accurately describing human leukocyte antigen diversity. In this study, we compared sample sets of publically available haplotype frequencies from different populations to characterize the consequences of unequal sample size on haplotype frequency estimation. We found that for low samples sizes (a few thousand), haplotype frequencies were overestimated, affecting all descriptive metrics of the underlying distribution, such as most frequent haplotype, the number of haplotypes, and the mean/median frequency.

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We have estimated human leukocyte antigen (HLA) haplotype frequencies using the maximum likelihood mode, which accommodates typing ambiguities. The results of the frequency distribution of the 7015 haplotypes obtained are presented here. These include a total of 114 HLA-A, 185 HLA-B, and 76 HLA-DRB1 unique alleles at each locus.

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Background: Stable dry-state storage of DNA is desirable to minimize required storage space and to reduce electrical and shipping costs. DNA purified from various commercially available dry-state stabilization matrices has been used successfully in downstream molecular applications (e.g.

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Article Synopsis
  • The study investigates how interferon-beta (IFN-β) affects the mitochondrial function and energy metabolism of CD4(+) T cells in multiple sclerosis (MS) patients.
  • It finds that IFN-β treatment leads to a significant decrease in intracellular ATP levels and changes in mitochondrial activity, indicating impaired energy supply in treated patients.
  • The research also suggests that genetic variations in the PGC-1α gene may influence patients' responses to IFN-β, highlighting complex mechanisms of the drug's action on cellular metabolism.
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Article Synopsis
  • Multiple sclerosis (MS) is a leading cause of chronic neurological disability in young adults, with genetic studies indicating that its inheritance involves multiple factors and genes, though not all associated risk factors are known.!* -
  • Researchers used a genome-wide association study (GWAS) with nearly 9,000 samples to identify 350 genetic markers linked to MS, calculating cumulative genetic risk and examining clinical characteristics across different risk levels.!* -
  • The findings revealed a high cumulative genetic risk in individuals with MS compared to controls, highlighting genes related to immune responses and neural signaling, but no significant differences in disease progression were found across various predicted genetic risk groups.!*
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Genetic polymorphisms and variable expression of drug receptors, metabolizing enzymes, and transporters have been linked to interindividual differences in efficacy and toxicity of many Food and Drug Administration-approved therapeutic agents. In multiple sclerosis, the combination of heterogeneity of disease pathology and significant variation in clinical response to disease-modifying agents necessitates the definition of biomarkers that can a priori predict therapeutic response and define appropriate therapeutic regimens. Pharmacogenomic studies will directly address the question of heterogeneity by analysis of the correlation between different genomic variants and clinical responses to therapy.

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Clinically isolated syndrome (CIS) refers to the earliest clinical manifestation of multiple sclerosis (MS). Currently there are no prognostic biological markers that accurately predict conversion of CIS to clinically definite MS (CDMS). Furthermore, the earliest molecular events in MS are still unknown.

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Some breast cancer cases in our previous immunohistochemical studies show Met expression in the nucleus. Given nuclear localization of other receptor tyrosine kinases, we proceeded to investigate Met. Nuclear Met is seen in numerous cell lines and in germinal regions of many tissues using four unique antibodies.

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Alpha-catenin functions to anchor adherens junctions to the filamentous actin (F-actin) cytoskeleton, through direct and indirect binding mechanisms. When truncated at amino acid 865, alpha-catenin exhibited a markedly reduced F-actin binding affinity compared to wild-type. Expression of the truncated mutant in the alpha-catenin deficient colon carcinoma cell line, Clone A, could not restore an adhesive phenotype when compared.

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