Publications by authors named "Dan Nicolae"

Article Synopsis
  • The review focuses on toxoplasmosis rates in Panama and Colombia, analyzing data on seroprevalence and risk factors.
  • Studies showed seroprevalence in Ciudad de Panamá ranged from 22% to 44%, with higher rates linked to poverty and closeness to water.
  • Heat maps and mathematical models were created to pinpoint areas that need targeted healthcare campaigns for congenital toxoplasmosis and infections.
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Background: Viruses may drive immune mechanisms responsible for chronic rhinosinusitis with nasal polyposis (CRSwNP), but little is known about the underlying molecular mechanisms.

Objectives: To identify epigenetic and transcriptional responses to a common upper respiratory pathogen, rhinovirus (RV), that are specific to patients with CRSwNP using a primary sinonasal epithelial cell culture model.

Methods: Airway epithelial cells were collected at surgery from patients with CRSwNP (cases) and from controls without sinus disease, cultured, and then exposed to RV or vehicle for 48 h.

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Article Synopsis
  • The purpose of the review was to develop and assess educational materials aimed at reducing disease burdens from infections in Panama, Colombia, and the USA.
  • Recent findings indicate that educational programs in these countries have not yet been evaluated for their effectiveness, despite being implemented for various demographics like high school students and pregnant women.
  • The summary highlights that these educational materials have shown short-term benefits in disseminating information, with future goals focusing on conducting long-term studies, updating materials based on new research, and increasing access to these resources for broader public health impact.
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Impaired lung function in early life is associated with the subsequent development of chronic respiratory disease. Most genetic associations with lung function have been identified in adults of European descent and therefore may not represent those most relevant to pediatric populations and populations of different ancestries. In this study, we performed genome-wide association analyses of lung function in a multiethnic cohort of children (n = 1,035) living in low-income urban neighborhoods.

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Purpose Of Review: Review building of programs to eliminate infections.

Recent Findings: Morbidity and mortality from toxoplasmosis led to programs in USA, Panama, and Colombia to facilitate understanding, treatment, prevention, and regional resources, incorporating student work.

Summary: Studies foundational for building recent, regional approaches/programs are reviewed.

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Article Synopsis
  • The review discusses international efforts to create a global public health initiative for toxoplasmosis, aiming to enhance maternal and child health by preventing and treating the disease.
  • Recent findings indicate that some countries are making progress in eliminating toxoplasmosis but face significant challenges.
  • Key issues include the high costs and inaccessibility of diagnostic tests and treatment, especially for marginalized communities, as well as delays in essential medical procedures and insurance processes.
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Many high dimensional and high-throughput biological datasets have complex sample correlation structures, which include longitudinal and multiple tissue data, as well as data with multiple treatment conditions or related individuals. These data, as well as nearly all high-throughput 'omic' data, are influenced by technical and biological factors unknown to the researcher, which, if unaccounted for, can severely obfuscate estimation of and inference on the effects of interest. We therefore developed CBCV and CorrConf: provably accurate and computationally efficient methods to choose the number of and estimate latent confounding factors present in high dimensional data with correlated or nonexchangeable residuals.

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Article Synopsis
  • Scientists studied how our genes might be linked to asthma in kids and adults, especially looking at a special part of our DNA called the HLA complex.
  • They used data from thousands of people to find out which specific genes and changes in the genes could make someone more likely to have asthma.
  • The findings show that different gene changes might affect asthma in kids and adults, and they found some important genes that could help explain why certain people get asthma.
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Background: Genome-wide association studies (GWASs) have identified thousands of variants associated with asthma and other complex diseases. However, the functional effects of most of these variants are unknown. Moreover, GWASs do not provide context-specific information on cell types or environmental factors that affect specific disease risks and outcomes.

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High throughput metabolomics data are fraught with both non-ignorable missing observations and unobserved factors that influence a metabolite's measured concentration, and it is well known that ignoring either of these complications can compromise estimators. However, current methods to analyze these data can only account for the missing data or unobserved factors, but not both. We therefore developed MetabMiss, a statistically rigorous method to account for both non-random missing data and latent factors in high throughput metabolomics data.

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Birth cohort studies have identified several temporal patterns of wheezing, only some of which are associated with asthma. Whether 17q12-21 genetic variants, which are closely associated with asthma, are also associated with childhood wheezing phenotypes remains poorly explored. To determine whether wheezing phenotypes, defined by latent class analysis (LCA), are associated with nine 17q12-21 SNPs and if so, whether these relationships differ by race/ancestry.

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There is a life-long relationship between rhinovirus (RV) infection and the development and clinical manifestations of asthma. In this study we demonstrate that cultured primary bronchial epithelial cells from adults with asthma (n = 9) show different transcriptional and chromatin responses to RV infection compared to those without asthma (n = 9). Both the number and magnitude of transcriptional and chromatin responses to RV were muted in cells from asthma cases compared to controls.

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Epigenetic architecture is influenced by genetic and environmental factors, but little is known about their relative contributions or longitudinal dynamics. Here, we studied DNA methylation (DNAm) at over 750,000 CpG sites in mononuclear blood cells collected at birth and age 7 from 196 children of primarily self-reported Black and Hispanic ethnicities to study race-associated DNAm patterns. We developed a novel Bayesian method for high-dimensional longitudinal data and showed that race-associated DNAm patterns at birth and age 7 are nearly identical.

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Background: The upper airways present a barrier to inhaled allergens and microbes, which alter immune responses and subsequent risk for diseases, such as allergic rhinitis (AR).

Objective: We tested the hypothesis that early-life microbial exposures leave a lasting signature in DNA methylation that ultimately influences the development of AR in children.

Methods: We studied upper airway microbiota at 1 week, 1 month, and 3 months of life, and measured DNA methylation and gene expression profiles in upper airway mucosal cells and assessed AR at age 6 years in children in the Copenhagen Prospective Studies on Asthma in Childhood birth cohort.

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Background: African ancestry is associated with a higher prevalence and greater severity of asthma than European ancestries, yet genetic studies of the most common locus associated with childhood-onset asthma, 17q12-21, in African Americans have been inconclusive. The aim of this study was to leverage both the phenotyping of the Children's Respiratory and Environmental Workgroup (CREW) birth cohort consortium, and the reduced linkage disequilibrium in African Americans, to fine map the 17q12-21 locus.

Methods: We first did a genetic association study and meta-analysis using 17q12-21 tag single-nucleotide polymorphisms (SNPs) for childhood-onset asthma in 1613 European American and 870 African American children from the CREW consortium.

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Article Synopsis
  • Asthma is a chronic inflammatory disease of the airways, and while studies have looked at its genetic roots, the role of HLA alleles has been underexplored until now.
  • This study focused on a large group of individuals of African ancestry to investigate associations between HLA alleles and asthma-related traits, using advanced computational techniques to analyze genetics.
  • Although no direct association with asthma susceptibility was found, the study identified a specific HLA allele linked to higher total serum IgE levels, highlighting the potential of advanced computational methods in understanding complex genetic associations.
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An important phenomenon in high-throughput biological data is the presence of unobserved covariates that can have a significant impact on the measured response. When these covariates are also correlated with the covariate of interest, ignoring or improperly estimating them can lead to inaccurate estimates of and spurious inference on the corresponding coefficients of interest in a multivariate linear model. We first prove that existing methods to account for these unobserved covariates often inflate Type I error for the null hypothesis that a given coefficient of interest is zero.

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Background: Childhood-onset and adult-onset asthma differ with respect to severity and comorbidities. Whether they also differ with respect to genetic risk factors has not been previously investigated in large samples. The goals of this study were to identify shared and distinct genetic risk loci for childhood-onset and adult-onset asthma, and to identify the genes that might mediate the effects of associated variation.

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Article Synopsis
  • Asthma affects people differently depending on their race, and there haven't been enough studies on people of African ancestry.
  • A new study looked at data from 7,009 people with asthma and 7,645 without, and found strong links to four previously known gene areas.
  • The study also discovered two new gene areas that might be especially important for asthma risk in people of African ancestry.
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The impact of the parental origin of associated alleles in GWAS has been largely ignored. Yet sequence variants could affect traits differently depending on whether they are inherited from the mother or the father, as in imprinted regions, where identical inherited DNA sequences can have different effects based on the parental origin. To explore parent-of-origin effects (POEs), we studied 21 quantitative phenotypes in a large Hutterite pedigree to identify variants with single parent (maternal-only or paternal-only) effects, and then variants with opposite parental effects.

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Integration of genome-wide association studies (GWAS) and expression quantitative trait loci (eQTL) studies is needed to improve our understanding of the biological mechanisms underlying GWAS hits, and our ability to identify therapeutic targets. Gene-level association methods such as PrediXcan can prioritize candidate targets. However, limited eQTL sample sizes and absence of relevant developmental and disease context restrict our ability to detect associations.

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In the version of this article initially published, the statement "there are no pan-genomes for any other animal or plant species" was incorrect. The statement has been corrected to "there are no reported pan-genomes for any other animal species, to our knowledge." We thank David Edwards for bringing this error to our attention.

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We used a deeply sequenced dataset of 910 individuals, all of African descent, to construct a set of DNA sequences that is present in these individuals but missing from the reference human genome. We aligned 1.19 trillion reads from the 910 individuals to the reference genome (GRCh38), collected all reads that failed to align, and assembled these reads into contiguous sequences (contigs).

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Objective: Asthmatic children who develop obesity through adolescence have poorer disease outcomes compared with those who do not. This study aimed to characterize the biology of childhood asthma complicated by adult obesity.

Methods: Gene expression networks are powerful statistical tools for characterizing human disease that leverage the putative coregulatory relationships of genes to infer relevant biological pathways.

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