PubMed HealthSearch

SEARCH · PubMed Health

Search PubMed Health

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

Parental son preference in childhood and sex differences in the risk of cardiovascular disease in middle-aged and older adults.

INTRODUCTION: Sex differences in cardiovascular disease (CVD) risk are examined through biological and clinical factors, with less attention to early-life social exposures. This study examined associations of childhood parental son preference with CVD risk, sex differences, and mediation by modifiable risk factors. METHODS: This cohort analysis included China Health and Retirement Longitudinal Study participants aged ≥45 years without baseline CVD. Parental son preference was assessed retrospectively in 2014; incident CVD was self-reported physician-diagnosed heart disease or stroke through 2020. Sampling-weighted, community-clustered Cox models estimated adjusted hazard ratios (aHRs) and 95% CIs. Sex was prespecified as an effect modifier; mediation by 13 risk factors used inverse-odds-ratio weighting. Data were collected from 2011 to 2020 and analyzed from 2025 to 2026. RESULTS: Among 8,079 participants (mean age, 57.5 years; 4,216 women [52.2%]), 1,820 (22.5%) reported parental son preference. Son preference was associated with higher CVD risk overall (aHR 1.23 [95% CI 1.04, 1.46]) and among women (aHR 1.25 [95% CI 1.03, 1.53]); among men, the estimate was 1.16 (95% CI 0.87, 1.56), with limited heterogeneity by sex (ratio of aHRs 1.06 [95% CI 0.72, 1.58]). Among women, risk was concentrated in the highest paternal (aHR 1.47 [95% CI 1.14, 1.90]) and maternal (aHR 1.50 [95% CI 1.12, 1.99]) preference categories. Modifiable risk factors mediated 5.8% (95% CI 1.9%, 9.7%) of the association among women, mainly through socioeconomic and psychosocial factors. CVD risk was highest with both son preference and high risk-factor burden overall (aHR 1.97 [95% CI 1.43, 2.73]) and among women (aHR 2.23 [95% CI 1.61, 3.10]). CONCLUSIONS: Parental son preference was associated with higher incident CVD risk, with the largest estimates in the highest paternal or maternal categories among women. Modifiable risk factors explained a modest proportion, supporting life-course cardiovascular prevention that considers sex-differentiated childhood environments alongside risk-factor modification.

cardiovascular disease

Effectiveness of high-dose versus standard-dose influenza vaccines against hospitalisation according to frailty risk: a prespecified analysis of the randomised trial DANFLU-2.

BACKGROUND: Frailty is a major risk factor for influenza-related complications and can influence vaccine effectiveness. We aimed to assess the relative vaccine effectiveness (rVE) of high-dose (HD-IIV) versus standard-dose inactivated influenza vaccine (SD-IIV) in older adults aged 65 years or older according to frailty risk. METHODS: This study was a prespecified analysis of DANFLU-2, an open-label, individually randomised trial, conducted in Denmark during three consecutive influenza seasons (2022-23, 2023-24, and 2024-25). Adults aged 65 years or older were randomised (1:1) to the HD-IIV or SD-IIV group. The primary endpoint was hospitalisation for influenza or pneumonia. Frailty was defined according to the validated Hospital Frailty Risk Score (HFRS) based on ICD-10 codes within 10 years before randomisation. Participants were stratified into three HFRS categories, namely low (<5 points), intermediate (5-15 points), and high (>15 points) frailty risk. The rVE of HD-IIV versus SD-IIV against the primary endpoint was assessed across prespecified HFRS categories and treating HFRS as a continuous variable. Pearson's chi-square test was used to compare safety events across frailty risk groups and randomisation groups. FINDINGS: Among 332&#x2009;438 randomised participants (mean age 73&#xb7;7 years [SD 5&#xb7;8]; 161&#x2009;538 [48&#xb7;6%] were female), 276&#x2009;173 (83&#xb7;1%) had low frailty risk, 52&#x2009;395 (15&#xb7;8%) had intermediate frailty risk, and 3861 (1&#xb7;2%) had high frailty risk. The primary endpoint of hospitalisation for influenza or pneumonia occurred in 1424 (0&#xb7;5%) of 276&#x2009;173 participants with low frailty risk, 761 (1&#xb7;5%) of 52&#x2009;395 with intermediate frailty risk, and 163 (4&#xb7;2%) of 3861 with high frailty risk (relative risk [RR] for intermediate vs low frailty risk 2&#xb7;8 [95% CI 2&#xb7;6-3&#xb7;1]; RR for high vs low frailty risk 8&#xb7;2 [7&#xb7;0-9&#xb7;6]). HFRS as a continuous variable significantly modified the effect of HD-IIV versus SD-IIV against the primary endpoint with higher rVE estimates with increasing HFRS (pinteraction=0&#xb7;020). The rVE was 0&#xb7;2% (95% CI -10&#xb7;8 to 10&#xb7;2) among those with low frailty risk, 13&#xb7;1% (-0&#xb7;4 to 24&#xb7;8) among those with intermediate frailty risk, and 19&#xb7;9% (-10&#xb7;3 to 42&#xb7;1) among those with high frailty risk. No significant interaction was observed when HFRS was assessed according to the prespecified categorical frailty groups (pinteraction=0&#xb7;17). The proportion of participants with at least one serious adverse event increased across frailty risk groups (13&#x2009;366 [4&#xb7;8%] of 275&#x2009;795 for low frailty risk, 5475 [10&#xb7;5%] of 52&#x2009;315 for intermediate frailty risk, and 777 [20&#xb7;2%] of 3850 for high frailty risk; p<0&#xb7;0001), with similar proportions of serious adverse events in the HD-IIV and SD-IIV groups for each frailty risk group. INTERPRETATION: Among adults aged 65 years or older in Denmark, frailty risk might modify the effects of HD-IIV versus SD-IIV against hospitalisation for influenza or pneumonia, with higher rVE estimates with increasing frailty risk. These findings might support considering high-dose influenza vaccines for frail older adults. However, effect modification was not evident when frailty was assessed using prespecified categorical subgroups, and subgroup-specific estimates were imprecise, with 95% CIs crossing the null. These results should be considered exploratory, warranting further investigation. FUNDING: The DANFLU-2 trial was funded by Sanofi.

Journal Article

Overview of Chikungunya Virus Epidemiology, Biology, and Pathogenesis.

Chikungunya virus (CHIKV), an arthropod-borne alphavirus within the Togaviridae family, is transmitted primarily by Aedes aegypti and Aedes albopictus. The virus causes an acute febrile illness characterized by severe, often bilateral polyarthralgia, with potential progression to chronic musculoskeletal pain and rare systemic complications involving cardiovascular and neurological systems. CHIKV exhibits a spherical, enveloped virion (~70&#x2009;nm) with T&#x2009;=&#x2009;4 icosahedral symmetry, incorporating E1/E2 glycoprotein heterodimers that mediate receptor binding and membrane fusion. Its positive-sense RNA genome (~11.8&#x2009;kb) encodes nonstructural proteins for replication and structural proteins for virion assembly. Replication occurs in cytoplasmic spherules, involving synthesis of genomic and subgenomic RNAs, followed by glycoprotein maturation and budding at the plasma membrane. Epidemiologically, CHIKV has expanded beyond Africa and Asia, with major outbreaks driven by adaptive mutations enhancing transmission via A. albopictus. Since introduction to the Americas in 2013, the global incidence remains high, with >180,000 confirmed cases reported in 2025. Preventive strategies rely on vector control and vaccination; VLP-based vaccines (e.g., Vimkunya) show promise, while live-attenuated formulations face safety concerns. No licensed antivirals exist; current management is supportive, though investigational therapies targeting viral replication and immune modulation are under development.

Chikungunya virus

Epitope Tagging and Coimmunoprecipitation to Identify Viral Protein Interactors.

Affinity purification-mass spectrometry (AP-MS) is a powerful proteomic approach for dissecting the interaction network between virus and host. Traditional AP-MS employs overexpression of viral proteins as baits to enrich host interactors. However, overexpressed viral proteins may mislocalize to inappropriate cellular compartments and trigger endoplasmic reticulum stress by overwhelming the protein-folding machinery, which leads to false identification of host factors. To overcome these limitations, we introduce an AP-MS strategy based on direct infection with an epitope-tagged chikungunya virus (CHIKV/myc-E2), which we used to successfully uncover two new antiviral factors in CHIKV cellular reservoirs-macrophages. In this protocol, we will describe this technique step by step: (1) design and construction of myc-tagged virus by advanced multi-fragment assembly, (2) in vitro transcription and preparation of infectious myc-tagged virus stocks, and (3) immunoprecipitation of myc-tagged viral protein and its interactome for mass spectrometry analysis. This strategy enables accurate identification of viral interactors in a physiologically relevant context, providing a framework for future proteomic studies using tagged viruses.

Chikungunya virus

Screening of Antiviral Agents Against CHIKV Using Reporter Virus.

Chikungunya virus (CHIKV) causes a disease characterized by chronic musculoskeletal inflammation for which specific antivirals are not yet available. Currently, a supportive therapy to alleviate fever and pain is used, but it does not limit viral replication or the persistence of chronic arthritis symptoms. Thus, the identification and development of new active molecules against CHIKV is urgently needed. Here, we present a cell-based methodology that enables the implementation of a rapid and cost-effective strategy for high- and medium-throughput screening (HTS) of compounds, including repurposed drugs or novel molecules. This methodology allows for the identification of novel antiviral hits with a good activity and selectivity profile against CHIKV.

Antiviral Agents

Global Genomic Surveillance.

Global genomic surveillance has emerged as a foundational pillar of public health in the twenty-first century, enabling real-time tracking of pathogen evolution and informing outbreak response. This chapter examines the strategic architecture of global genomic surveillance, focusing on its application to arboviruses such as chikungunya virus (CHIKV). It explores the integration of genomic data with epidemiological, clinical, and environmental information within a One Health framework, while addressing critical challenges in governance, equity, and interoperability. The discussion covers the entire genomic surveillance workflow, from sample collection and sequencing to bioinformatic analysis and phylogenetic inference, and highlights the transformative role of artificial intelligence (AI) in predictive surveillance. By analyzing global initiatives, operational barriers, and emerging technologies, this chapter underscores the necessity of sustainable, equitable, and interoperable genomic systems to proactively address current and future infectious disease threats.

Humans

Nanopore Sequencing for Chikungunya Virus: Principles and Application.

Nanopore sequencing is transforming viral genomics through real-time, portable, long-read analysis of RNA and DNA. Unlike traditional short-read platforms, it detects nucleotide sequences by measuring ionic current changes as nucleic acids pass through nanoscale pores, enabling direct single-molecule sequencing and base modification detection. Its simplicity, flexibility, and capacity for ultra-long reads make it ideal for resolving complex genomic regions, structural variants, and full viral genomes. These advantages have accelerated its use in pathogen surveillance and outbreak response, especially in resource-limited settings. For chikungunya virus (CHIKV), nanopore sequencing allows rapid, culture-independent recovery of complete genomes from clinical and vector samples, enabling real-time tracking of viral diversity, evolution, and spread. Experiences from Ebola, Zika, and COVID-19 have demonstrated the power of portable sequencing, now applied to CHIKV monitoring. Advances in tools such as Guppy, Dorado, Minimap2, and Medaka enhance read quality, consensus accuracy, and downstream analyses. Despite challenges in basecalling and error correction, robust quality control pipelines ensure reliable results. Ongoing improvements in chemistry, flow cell design, and machine learning will further enhance fidelity and throughput, establishing nanopore sequencing as a cornerstone of CHIKV genomic surveillance and epidemic preparedness.

Chikungunya virus

Workflow for Long-Read Amplicon Sequencing of Chikungunya Virus Using Oxford Nanopore Technology.

This protocol provides a comprehensive, step-by-step workflow for whole-genome sequencing of Chikungunya virus (CHIKV) using an amplicon-based strategy optimized for Oxford Nanopore Technologies (ONT) platforms. The procedure includes detailed instructions for sample handling, viral RNA extraction, quality control, cDNA synthesis, multiplex PCR amplification, library preparation, sequencing, and primary bioinformatic processing. The protocol is designed to maximize reproducibility across laboratories and is suitable for genomic surveillance applications, including outbreak investigation and molecular epidemiology, even when working with low-to-moderate viral loads.

Chikungunya virus

Optimized Amplicon Strategy for Long-Read Sequencing of the Chikungunya Virus Genome.

Chikungunya virus (CHIKV) is a positive-sense RNA alphavirus transmitted to humans primarily by Aedes aegypti and Aedes albopictus mosquitoes. Its global circulation and significant public health impact underscore the need to better understand the molecular mechanisms driving CHIKV pathogenesis and transmission. Although robust molecular biology methods exist for CHIKV genome sequencing, a major limitation for surveillance and research is the inability to determine whether two nucleotide variations co-occur within the same viral genome when they are separated beyond the span of typical short-read designs. Here, we describe an optimized approach for processing CHIKV RNA samples that generates large amplicons suitable for long-read nanopore sequencing. This protocol enables amplification of the complete CHIKV genome in only two or three amplicons and facilitates detection of co-occurring nucleotide variations across 4-7.5&#x2009;kb within the same molecule, thereby simplifying sequencing workflows and improving resolution in studies of viral evolution.

Chikungunya virus

Protocol for Detecting and Sequencing Chikungunya Virus from Field-Collected Mosquitoes.

Arboviral diseases represent a major public health challenge, especially in tropical regions where environmental conditions may favor the proliferation and spread of mosquito vectors. Thus, early and accurate detection of chikungunya virus (CHIKV) in mosquito populations can be a valuable tool for effective surveillance of circulating variants and for identifying new viral introductions. Given the challenges of detecting arboviruses in field-captured mosquitoes, we describe an integrated workflow for CHIKV molecular detection and whole-genome sequencing. This protocol includes mosquito homogenization using a bead-based mechanical disruptor, RNA extraction using TRIzol reagent with minor modifications, molecular screening using CHIKV-specific RT-qPCR, and whole-genome amplification followed by sequencing on Illumina platforms. Despite the protocol being optimized for individual mosquitoes, it results in high-quality RNA suitable for both entomological surveillance and genomic analysis. As this protocol allows recovery of complete CHIKV genomes from mosquito specimens, it can serve as a basis for genomic epidemiology studies, enabling monitoring of viral diversity and lineage dynamics, and facilitating early detection of emerging variants to support timely and targeted public health interventions in endemic and at-risk regions.

Animals

RT-RPA-Assisted CRISPR/Cas12a-Based Isothermal Detection of Chikungunya Virus.

Chikungunya virus (CHIKV) is transmitted through the bite of Aedes mosquitoes, specifically A. aegypti and A. albopictus. CHIKV belongs to the alphavirus with a positive-sense ssRNA genome of 11-12&#x2009;kb size. The virus has been reported from various geographical regions across the globe. Chikungunya fever is an acute febrile illness, which, if left untreated, may develop into chronic arthralgia that may persist for several months or acute encephalitis syndrome. Therefore, early diagnosis of CHIKV is crucial to initiate prompt supportive treatment. Laboratory diagnosis of CHIKV typically relies on serological tests such as IgM antigen capture ELISA and molecular methods including RT-PCR or qRT-PCR. However, both these methods are not viable in peripheral settings. This chapter highlights recent advancements in molecular detection techniques for CHIKV, specifically isothermal detection methods that eliminate the requirement for complex instruments. The detection is facilitated by RT-RPA and CRISPR/Cas12a endonuclease. The assay offers advantages over existing methods such as rapid and early detection, and eliminates cross-over contamination, ultra-sensitivity, high specificity, and ease of result interpretation.

Chikungunya virus

Production of Viral Particles from a Chikungunya Virus Infectious Clone.

Chikungunya virus (CHIKV) is a positive-sense single-stranded RNA virus, which poses challenges for its study and genetic manipulation. Because direct mutagenesis of viral RNA genomes is technically impractical, reverse genetics systems are essential tools for investigating viral biology. To enable such approaches, infectious clones containing a full-length cDNA copy of the viral genome are constructed. The cDNA is positioned under the control of a bacteriophage RNA polymerase promoter, allowing commercial RNA polymerases to use the linearized plasmid as a template for the in vitro transcription of full-length viral genomic RNA (gRNA). Importantly, positive-sense viral genomes serve as mRNAs for the translation of viral proteins in a cellular environment, meaning that these transcripts contain all the information required to initiate viral replication. Following transfection into permissive cultured cells, viral proteins are expressed, enabling genome replication and, ultimately, the recovery of infectious particles from the cell supernatant. Here, we describe a detailed procedure for generating CHIKV particles through plasmid linearization, in vitro transcription, and subsequent RNA transfection.

Chikungunya virus

Molecular Cloning and Reverse Genetics.

This chapter describes a detailed molecular biology protocol for introducing specific point mutations into the chikungunya virus (CHIKV) genome using a reverse genetics strategy. The method utilizes an overlapping PCR-based approach to generate a mutated DNA fragment, which is then cloned into a pre-engineered CHIKV infectious clone plasmid. The protocol covers all major steps, from the initial PCRs to create the mutated insert to its digestion and ligation into the vector. It also includes procedures for bacterial transformation, colony screening via PCR and Sanger sequencing to confirm the mutation, and plasmid purification via miniprep. The document is structured with a clear introduction, a list of all required reagents and equipment, and a step-by-step methods section.

Cloning, Molecular

A Restriction-Free Cloning Approach for Molecular Engineering of Plasmids.

Molecular cloning by PCR amplification using a highly processive, high-fidelity DNA polymerase represents a robust and versatile technique for the precise manipulation of nucleic acid sequences. This approach enables the insertion, replacement, or modification of specific DNA fragments within a cloning vector, thereby generating an accurate copy of a gene or viral segment for downstream applications, such as protein expression, site-directed mutagenesis, and structural or functional analyses. The use of processive, high-fidelity polymerases significantly reduces the occurrence of base substitution errors, ensuring sequence integrity throughout the amplification process. Traditionally, restriction enzymes have been employed to facilitate directional cloning; however, alternative methods allow for mutagenesis without the need for unique and specific restriction sites and can be applied to virtually any cloning or seamless DNA assembly strategy. In this chapter, we describe a restriction enzyme-free and ligation-free PCR-based protocol widely applicable to any circular vector. This method enables targeted mutagenesis of the chikungunya virus (CHIKV) genome, offering a fast, efficient, and reliable strategy for generating mutant constructs suitable for virological and molecular studies.

Cloning, Molecular

Inferring Gene Regulatory Networks in Stem Cells: Methods and Applications.

Gene regulatory networks (GRNs) represent the complex interplay of transcription factors, regulatory elements, and target genes that orchestrate cellular identity and function, playing a crucial role in the differentiation and maintenance of stem cells. This chapter provides an overview of experimental and computational methodologies for inferring GRNs, with particular emphasis on single-cell approaches. We first review key experimental techniques for detecting transcription factor binding sites, chromatin accessibility, and DNA motifs, alongside essential databases that support GRN reconstruction. We then introduce computational inference methods that can be categorized into four principal frameworks: correlation-based approaches, regression and machine learning models, probabilistic and deep learning methods, and integrative or message-passing frameworks. To illustrate practical application, we present a case study applying the pySCENIC workflow to a peripheral blood mononuclear cell single-cell RNA sequencing dataset from mouse, demonstrating how regulon-based analysis can reveal cell-type-specific regulatory programs. This chapter aims to serve as a practical guide for researchers seeking to understand and implement GRN inference methodologies in stem cell biology and related fields.

Gene Regulatory Networks

Systematic Analysis of Tumor Microenvironment Using IOBR.

The Immuno-Oncology Biological Research (IOBR) package is an R-based analysis tool for exploring the tumor microenvironment (TME) and its influence on anti-tumor immunity. Built for high-throughput data-spanning both transcriptomic and genomic profiles-IOBR integrates six analytical modules, including transcriptomic data preprocessing, TME profiling, TME pattern identification, ligand-receptor interaction analysis, genome-TME interaction assessment, and visualization. In this chapter, we walk through a multi-omics workflow using example datasets, illustrating data preparation, distribution analyses, result interpretation, and graphical output. IOBR is open source and is available at https://github.com/IOBR/IOBR and a detailed GitBook ( https://iobr.github.io/book/ ) offers a complete manual and analysis guide for each function.

Tumor Microenvironment

Systematic Dissection of Key Driver Perturbation Signatures in Single Cells via ECCITE-seq.

CRISPR screens, such as expanded CRISPR-compatible cellular indexing of transcriptomes and epitopes by sequencing (ECCITE-seq), enable the simultaneous measurement of transcriptomes, gRNA identity, and cell-surface protein expression at single-cell resolution to systematically interrogate gene function. This platform provides a powerful and scalable experimental approach for validating disease-associated regulators identified by large-scale association studies and other computational methods, including network-based analyses of multi-omics data. Here, as an example application, we describe an ECCITE-seq framework to characterize the transcriptomic consequences of perturbing multiple neuronal key driver genes associated with Alzheimer's disease (AD) in human-induced pluripotent stem cell (hiPSC)-derived neurons. More broadly, by integrating customized pooled gRNA libraries with different CRISPR effectors across multiple cell types, this approach allows for the assessment of the regulatory impact of candidate genes implicated in development and disease processes.

Humans

Genomic Profiling of Chromatin State Using CUT&Tag.

Alterations in chromatin state, mediated through histone modifications and the incorporation of histone variants, are fundamental to establishing transcriptional networks and cell identity. Recent advances in low-input epigenome profiling methods, such as CUT&Tag and CUT&RUN, have enabled the study of chromatin states from very limited starting materials. In this chapter, we describe procedures for generating CUT&Tag libraries to profile histone modifications and histone variants in early-developing zebrafish embryos.

Animals