Publications by authors named "Kevin Lau"

Heat-health warning systems and services are important preventive actions for extreme heat, however, global evidence differs on which temperature indicator is more informative for heat-health outcomes. We comprehensively assessed temperature predictors on their summer associations with adverse health impacts in a high-density subtropical city. Maximum, mean, and minimum temperatures were examined on their associations with non-cancer mortality and hospital admissions in Hong Kong during summer seasons 2010-2019 using Generalized Additive Models and Distributed Lag Non-linear Models.

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Cardiovascular aging is strongly associated with increased risk of cardiovascular disease and mortality. Moreover, health and lifestyle factors may accelerate age-induced alterations, such as increased arterial stiffness and wall dilation, beyond chronological age, making the clinical assessment of cardiovascular aging an important prompt for preventative action. Carotid flow waveforms contain information about age-dependent cardiovascular properties, and their ease of measurement via noninvasive Doppler ultrasound (US) makes their analysis a promising tool for the routine assessment of cardiovascular aging.

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Background: Extreme hot weather events are happening with increasing frequency, intensity and duration in Hong Kong. Heat stress is related to higher risk of mortality and morbidity, with older adults being particularly vulnerable. It is not clear whether and how the older adults perceive the increasingly hot weather as a health threat, and whether community service providers are aware and prepared for such future climate scenario.

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The urban heat island (UHI) effect exacerbates the adverse impact of heat on human health. However, while the UHI effect is further intensified during extreme heat events, prior studies have rarely mapped the UHI effect during extreme heat events to assess its direct temperature impact on mortality. This study examined the UHI effect during extreme heat and non-extreme heat scenarios and compared their temperature-mortality associations in Hong Kong from 2010 to 2019.

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Background: Autoimmunity has been reported in patients with severe coronavirus disease 2019 (COVID-19). We investigated whether anti-nuclear/extractable-nuclear antibodies (ANAs/ENAs) were present up to a year after infection, and if they were associated with the development of clinically relevant post-acute sequalae of COVID-19 (PASC) symptoms.

Methods: A rapid-assessment line immunoassay was used to measure circulating levels of ANAs/ENAs in 106 convalescent COVID-19 patients with varying acute phase severities at 3, 6 and 12 months post-recovery.

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Background: Single nucleotide polymorphisms (SNPs) of peroxisome proliferator-activated receptor gamma (PPAR-γ; gene: PPARG) and oxidative stress genes are associated with asthma risk. However, whether such variants modulate responses to dibutyl phthalate (DBP), a common plasticizer associated with increased asthma development, remains unknown. The purpose of this study is to investigate how SNPs in PPARG and oxidative stress genes, as represented by two separate genetic risk scores, modify the impact of DBP exposure on lung function and the airway and systemic response after an inhaled allergen challenge.

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Background: Literature reporting the association between heat stress defined by universal thermal climate index (UTCI) and emergency department visits is mainly conducted in Europe. This study aimed to investigate the association between heat stress, as defined by the UTCI, and visits to the accident and emergency department (AED) in Hong Kong, which represents a subtropical climate region.

Methods: A retrospective study involving 13,438,846 AED visits in the public sector from May 2000 to September 2016, excluding 2003 and 2009, was conducted in Hong Kong.

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According to the United Nations Office for Disaster Risk Reduction (UNDRR), a heat-health action plan should address various impacts of hazards at different levels, including an early warning system to monitor risks and behaviour enhancement to increase disaster preparedness. It is necessary to comply with guidelines regarding heat duration/intensity. In this study, we developed a data-driven approach to rapidly and systematically estimate the impacts of various heat events on emergency admissions among the adult population (n = 7,086,966) in Hong Kong in order to enhance the heat-health action plan.

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Background: Exposure to traffic-related air pollution is associated with increased morbidity and mortality. Negative health impact of diesel exhaust (DE) exposure may in part be mediated via epigenetic modulation. Ten-eleven translocation (TET) enzymes catalyze the active DNA demethylation process and play important roles in epigenetic regulation.

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There is growing evidence that chronic obstructive pulmonary disease (COPD) can be caused and exacerbated by air pollution exposure. To document the impact of short-term air pollution exposure on inflammation markers, proteases, and antiproteases in the lower airways of older adults with and without COPD. Thirty participants (10 ex-smokers with mild to moderate COPD and 20 healthy participants [9 ex-smokers and 11 never-smokers]), with an average age of 60 years, completed this double-blinded, controlled, human crossover exposure study.

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Urban overheating (due to climate change and urbanization) and COVID-19 are two converging crises that must be addressed in tandem. Fine-scale, place-based, people-centric biometeorological and behavioral data are needed to implement context-specific preventative measures such as mask-wearing. This study collected local biometeorological measurements in diverse urban spaces (square, urban park, river quay) in Novi Sad, Serbia on hot sunny summer days (27-30 August 2020) during the COVID-19 pandemic.

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The late enhanced magnetic resonance image dataset in this article is simulated using a mechanistic cardiac phantom that includes an myocardial infarct. Settings of the image simulation pipeline are adjusted such that high- and low-resolution images, with and without slice alignment artifacts, are simulated. Our article on the influence of image artifacts on image-based models of the cardiac electrophysiology is based on this data (Kruithof et al.

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The analysis of carotid ultrasound (US) flow, velocity, and diameter waveforms provides important information about cardiovascular and circulatory health. These can be used to derive clinical indices of atherosclerosis, vascular aging, and hemodynamic status. To derive clinical insight from carotid waveforms, it is essential to understand the relationship of the observed variability in morphology with the underlying hemodynamic status and cardiovascular properties.

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A comprehensive understanding of the interaction between triggers and electrical substrates leading to ventricular fibrillation (VF) and sudden cardiac arrest is lacking, and electrical substrates are difficult to detect and localize with current clinical tools. Here, we created repolarization time (RT) dispersion by regional drug infusion in perfused explanted human ( = 1) and porcine ( = 6) hearts and in a computational model of the human ventricle. Arrhythmia induction was tested with a single ventricular extrastimulus applied at the early or late RT region.

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Background: One major limitation of prior studies regarding the associations between built environment (BE) and obesity has been the use of anthropometric indices (e.g., body mass index [BMI]) for assessing obesity status, and there has been limited evidence of associations between BE and body fat.

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Article Synopsis
  • CRIMSON (CardiovasculaR Integrated Modelling and SimulatiON) is a versatile software tool designed for 3D computational studies of blood flow, focusing on ease of use for diverse users like clinicians and students.
  • The software streamlines processes including image segmentation of blood vessels, model construction, finite element mesh generation, and running simulations that include fluid-structure interactions.
  • It has global usage across multiple continents and is applied in various clinical scenarios, such as surgical planning and optimizing medical device designs.
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Purpose: Rosacea is a common cause of ocular surface disease. Specific immunologic features have been implicated in its pathogenesis, including toll-like receptors, mitogen-associated kinase, and nuclear factor kappa-B. Myeolid differentiation factor 88 (MYD88) has been associated with these elements, suggesting a role for this protein in rosacea.

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Background: Hong Kong lacks comprehensive school-based sexuality education. Recent public health concerns have brought the inadequacies of sex education in Hong Kong to the forefront. The aim of the proposed study is to develop and evaluate the effectiveness of a comprehensive school-based sexuality education program in Hong Kong.

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Purpose: To compare the expression of cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and lymphocyte activation gene-3 (LAG-3) in nodular and orbitally-invasive forms of basal cell carcinoma (BCC).

Methods: Immunohistochemical staining for CTLA-4 and LAG-3 was performed on the pathology specimens of BCC from orbital exenteration and nodular forms. The numbers of positively-staining cells/×40 field were counted across 5 consecutive fields of each specimen and statistical analysis was performed to calculate the difference in expression between the 2 groups.

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Background: Allergic bronchopulmonary aspergillosis (ABPA) reflects hypersensitivity and an exaggerated immune response to . ABPA typically occurs in individuals with airway diseases such as asthma or cystic fibrosis and is associated with worse outcomes for individuals with these conditions. Each year, physicians across the province of British Columbia submit over 2600 diagnostic testing requests to a centralized location in Vancouver, requiring specimen collection, storage, and shipment from different clinics across the province.

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A large number of studies have focused on the associations between single built environment (BE) characteristics and physical activity (PA). Combinations of BE characteristics offer a more comprehensive approach to identify the BE-PA associations. We aimed to examine the BE-PA associations in a cohort of elderly Hong Kong Chinese.

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Rationale: Exposure to air pollution is linked with increased asthma morbidity and mortality. To understand pathological processes linking air pollution and allergen exposures to asthma pathophysiology, we investigated the effect of coexposure to diesel exhaust (DE) and aeroallergen on immune regulatory proteins in human airways.

Methods: Fourteen allergen-sensitised participants completed this randomised, double-blinded, cross-over, controlled exposure study.

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Article Synopsis
  • Archetypal human pluripotent stem cells (hPSC) are thought to be similar to mouse epiblast stem cells, but variability within hPSC cultures makes this comparison tricky.
  • A specific subpopulation of hPSC known as ESR exhibits unique traits, including a low G1 cell cycle fraction and a distinctive metabolism that combines oxidative phosphorylation and glycolysis.
  • ESR cells are highly pluripotent, can differentiate into germ cell-like cells, and represent an earlier developmental stage than mouse epiblast stem cells, with different DNA methylation patterns and chromatin accessibility.
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The re-integration of trees into the urban landscape is a veritable strategy for urban climate mitigation and adaptation. However, dysfunctional trees in terms of urban heat mitigation are dominant in many sub-tropical cities' landscapes due to the lack of scientific basis of tree selection. Therefore, this study proposes and evaluates a methodological framework as an approach for "right tree, right place" for urban heat mitigation through parametric ENVI-met simulations that involve the combination of 54 generic tree forms and 10 characteristic urban morphology - Sky-View Factor (SVF).

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