Publications by authors named "Hak S"

Background: The majority of respiratory syncytial virus (RSV) infections in young children are managed in primary care, however, the disease burden in this setting remains poorly defined.

Methods: We did a prospective cohort study in primary care settings in Belgium, Italy, Spain, the Netherlands, and the UK during the RSV seasons of 2020-21 (UK only; from Jan 1, 2021), 2021-22, and 2022-23. Children aged younger than 5 years presenting to their general practitioner or primary care paediatrician with symptoms of an acute respiratory tract infection were eligible for RSV testing.

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Cancer immunotherapy has evolved significantly over the last decade, with therapeutics targeting the adaptive immune system showing exciting effects in clinics. Yet, the modulation of the innate immune system, particularly the tumor-associated innate immune cells which are an integral part of immune responses in cancer, remains less understood. The arginase 1 (Arg1) pathway is a pivotal metabolic pathway that tumor-associated innate immune cells exploit to create an immunosuppressive tumor microenvironment, leading to the evasion of immune surveillance.

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Article Synopsis
  • RSV is a significant cause of infant mortality and poses health risks for older adults, prompting the development of various vaccines and treatments, including a protein-based maternal vaccine and monoclonal antibodies (mAb) specifically for infants.* -
  • High-income countries have seen public health benefits from using nirsevimab, and several vaccines for older adults have also been approved, with ongoing clinical trials for multiple vaccine types targeting different age groups.* -
  • There's a need to address disparities in vaccine access, especially in low- and middle-income countries, with plans to advance RSV vaccination efforts globally in the near future.*
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Background: This study was conducted to investigate whether mRNA vaccine technology could be adapted for the ectothermic vertebrate Atlantic salmon (). Lipid nanoparticle (LNP) technology has been developed and optimized for mRNA vaccines in mammals, stabilizing mRNA and facilitating its delivery into cells. However, its utility at the temperatures and specific biological environments present in ectotherms remains unclear.

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Production and storage of synthetic mRNA can introduce a variety of byproducts which reduce the overall integrity and functionality of mRNA vaccines and therapeutics. mRNA integrity is therefore designated as a critical quality attribute which must be evaluated with state-of-the-art analytical methods before clinical use. The current study first demonstrates the effect of heat degradation on transcript translatability and then describes a novel enzymatic approach to assess the integrity of conventional mRNA and long self-amplifying mRNA.

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Background: During the first year of life, 1 in 4 infants develops a symptomatic respiratory syncytial virus (RSV) infection, yet only half seek medical attention. The current focus on medically attended RSV therefore underrepresents the true societal burden of RSV. We assessed the burden of nonmedically attended RSV infections and compared with medically attended RSV.

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Polyethylene glycol (PEG) conjugation (PEGylation) is a well-established strategy to improve the pharmacokinetic and biocompatibility properties of a wide variety of nanomedicines and therapeutic peptides and proteins. This broad use makes PEG an attractive 'allround' candidate marker for the biodistribution of such PEGylated compounds. This paper presents the development of a novel strategy for PEG quantification in biological matrices.

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Article Synopsis
  • The review discusses the importance of new RSV (respiratory syncytial virus) prevention interventions for healthcare professionals to help inform and counsel parents.
  • Recent studies highlight that RSV significantly impacts young children, with a notable percentage requiring medical attention and hospitalization during their first year of life.
  • New maternal vaccines and long-acting monoclonal antibodies (mAb) have shown high effectiveness in reducing severe RSV infections in infants and have been approved for use in the US and Europe, emphasizing the need for tailored parental guidance.
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Background: Myeloid cells play an essential role in cancer metastasis. The phenotypic diversity of these cells during cancer development has attracted great interest; however, their functional heterogeneity and plasticity have limited their role as prognostic markers and therapeutic targets.

Methods: To identify markers associated with myeloid cells in metastatic tumours, we compared transcriptomic data from immune cells sorted from metastatic and non-metastatic mammary tumours grown in BALB/cJ mice.

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Nanomedicine holds immense potential for therapeutic manipulation of phagocytic immune cells. However, in vitro studies often fail to accurately translate to the complex in vivo environment. To address this gap, we employed an ex vivo human whole-blood assay to evaluate liposome interactions with immune cells.

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Studies have shown an association between Early Childhood Caries (ECC) and respiratory infections; however, most have been cross-sectional, and all have been in high-income countries. Inverse probability treatment weighting (IPTW) was applied to longitudinal data from the Cambodia Health and Nutrition Monitoring Study. An analytical sample of 1703 Cambodian children between 1- and 4-years old was used to examine the effect of caries incidence (ECC Activity) on the odds of a child subsequently experiencing an episode of prolonged coughing (>14 days) over the subsequent 18 m.

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Evidence suggests that dental caries is associated with chronic and acute malnutrition, manifested as stunting and wasting in children. However, studies have not always appropriately accounted for confounding factors or for the temporal ordering between exposure and outcome. This study examined relationships between the development of caries lesions with subsequent stunting and wasting outcomes using data from a population-based cohort in Cambodia.

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Intravital microscopy (IVM) expands our understanding of cellular and molecular processes, with applications ranging from fundamental biology to (patho)physiology and immunology, as well as from drug delivery to drug processing and drug efficacy testing. In this review, we highlight modalities, methods and model organisms that make up today's IVM landscape, and we present how IVM - via its high spatiotemporal resolution - enables analysis of metabolites, small molecules, nanoparticles, immune cells, and the (tumor) tissue microenvironment. We furthermore present examples of how IVM facilitates the elucidation of nanomedicine kinetics and targeting mechanisms, as well as of biological processes such as immune cell death, host-pathogen interactions, metabolic states, and disease progression.

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Background: The evidence around the relationship between Early Childhood Caries (ECC) and undernutrition is sparse and mostly reported from cross-sectional data sets. This paper aimed to test the relationship between ECC and linear and ponderal growth trajectories.

Methods: This project involves secondary data analysis from the Cambodia Longitudinal Health and Nutrition Study.

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Lipid-based nanoparticles for RNA delivery (LNP-RNA) are revolutionizing the nanomedicine field, with one approved gene therapy formulation and two approved vaccines against COVID-19, as well as multiple ongoing clinical trials. As for other innovative nanopharmaceuticals (NPhs), the advancement of robust methods to assess their quality and safety profiles-in line with regulatory needs-is critical for facilitating their development and clinical translation. Asymmetric-flow field-flow fractionation coupled to multiple online optical detectors (MD-AF4) is considered a very versatile and robust approach for the physical characterisation of nanocarriers, and has been used successfully for measuring particle size, polydispersity and physical stability of lipid-based systems, including liposomes and solid lipid nanoparticles.

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Background: The persistently high prevalence of undernutrition in Cambodia, in particular stunting or chronic malnutrition, calls for innovative investigation into the risk factors that affect children's growth during critical phases of development.

Methods: Secondary data analysis was performed on a subgroup of children who were present at two time points within the Cambodian Health and Nutrition Monitoring Study (CAHENMS) and who were less than 24 months of age at the nominated baseline. Data consisted of parent interviews on sociodemographic characteristics and feeding practices, and clinical measures for anthropometric measures and dental status.

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Trained immunity, a functional state of myeloid cells, has been proposed as a compelling immune-oncological target. Its efficient induction requires direct engagement of myeloid progenitors in the bone marrow. For this purpose, we developed a bone marrow-avid nanobiologic platform designed specifically to induce trained immunity.

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Melatonin is a neurohormone with potenial therapeutic effects in many diseases including neonatal hypoxic-ischemic (HI) brain injury. Due to limited solubility in water there is currently no clinically available melatonin formulation for parenteral use. Clinical use of melatonin has thus relied on oral administration, which in many cases is hampered by low and variable bioavailability.

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Although the first nanomedicine was clinically approved more than two decades ago, nanoparticles' (NP) behavior is complex and the immune system's role in their application remains elusive. At present, only passive-targeting nanoformulations have been clinically approved, while more complicated active-targeting strategies typically fail to advance from the early clinical phase stage. This absence of clinical translation is, among others, due to the very limited understanding for targeting mechanisms.

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Ischaemic heart disease evokes a complex immune response. However, tools to track the systemic behaviour and dynamics of leukocytes non-invasively in vivo are lacking. Here, we present a multimodal hot-spot imaging approach using an innovative high-density lipoprotein-derived nanotracer with a perfluoro-crown ether payload (F-HDL) to allow myeloid cell tracking by F magnetic resonance imaging.

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Tumor associated macrophages are an essential part of the tumor microenvironment. Consequently, bone marrow-derived monocytes (BMDMs) are continuously recruited to tumors and are therefore seen as ideal delivery vehicles with tumor-targeting properties. By using immune cell depleting agents and macroscopic in vivo fluorescence imaging, we demonstrated that removal of endogenous monocytes and macrophages (but not neutrophils) leads to an increased tumor accumulation of exogenously administered BMDMs.

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Purpose: The endeavor of deciphering intricate phenomena within the field of molecular medicine dictates the necessity to investigate tumor/disease microenvironment real-time on cellular level. We, hereby, design simple and robust intravital microscopy strategies, which can be used to elucidate cellular or molecular interactions in a fluorescent mouse model.

Procedures: We crossbred transgenic TIE2GFP mice with nude BALB/c mice, allowing the breeding of immunocompetent and immunodeficient mouse models expressing green fluorescent protein (GFP) in vascular endothelium.

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Background: The Southeast Asian Forum for Early Childhood Caries identified the need for more epidemiological surveys involving preschool children. To date, the only data on Early Childhood Caries in Cambodia come from convenience samples and only using the basic dmft index without measurement of the early signs of disease.

Methods: A cross-sectional survey on an epidemiological sample of Cambodian preschool children was conducted in conjunction with the fourth follow-up of the Cambodian Health and Nutrition Monitoring Study.

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Background: We aimed to assess whether final height in children with cystic fibrosis (CF) is affected by body mass index (BMI), BMI increase, pulmonary function, and cystic fibrosis-related diabetes (CFRD).

Study Design: A longitudinal, retrospective study was performed in a cohort of 57 patients with CF (30 boys, 27 girls) born between 1997 and 2001. Height and weight were recorded annually from ages 0.

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