Publications by authors named "Lea H"

Background: Early host immunity to acute respiratory infections (ARIs) is heterogenous, dynamic, and critical to an individual's infection outcome. Due to limitations in sampling frequency/timepoints, kinetics of early immune dynamics in natural human infections remain poorly understood. In this nationwide prospective cohort study, we leveraged a Tasso-SST based self-blood collection and stabilization tool (homeRNA) to profile detailed kinetics of the presymptomatic to convalescence host immunity to contemporaneous respiratory pathogens.

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  • Scientists studied how men and women feel different temperatures to see if women really are colder than men.
  • They found that women can feel cold at a lower temperature (about 21.9 °C) than men (about 22.9 °C) because women usually have more body fat for insulation.
  • However, both men and women reacted similarly in other ways to cold, showing that body size and composition are the main reasons for feeling different temperatures, not just being a boy or a girl.
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  • This study investigates the dynamics of early immune responses to acute respiratory infections (ARIs), focusing on how an individual's immune system reacts before and after symptoms appear.
  • Researchers used a self-sampling method to collect blood and nasal swabs from participants daily for a week and weekly afterward, analyzing samples to monitor immune gene activity and symptom development.
  • A total of 68 participants contributed samples over the study period, with notable findings including that SARS-CoV-2 was detected in various participants, even when they showed no symptoms, offering insights into presymptomatic immune profiles.
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  • Blood transcriptional profiling is used to evaluate immune responses to infections, but traditional blood collection methods hinder accurate analysis during dynamic infections like COVID-19.
  • A new at-home self-collection method allows participants to collect blood and nasal swabs every other day, enabling high-frequency measurement of immune response during acute SARS-CoV-2 infections.
  • The study found significant differences in immune responses between healthy and COVID-19+ individuals, revealing distinct patterns based on vaccination status, and demonstrating the effectiveness of at-home sampling in tracking immune kinetics.
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Lumen structures exist throughout the human body, and the vessels of the circulatory system are essential for carrying nutrients and oxygen and regulating inflammation. Vasodilation, the widening of the blood vessel lumen, is important to the immune response as it increases blood flow to a site of inflammation, raises local temperature, and enables optimal immune system function. A common method for studying vasodilation uses excised vessels from animals; major drawbacks include heterogeneity in vessel shape and size, time-consuming procedures, sacrificing animals, and differences between animal and human biology.

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Physical activity (PA) is globally recognized as a pillar of general health. Step count, as one measure of PA, is a well known predictor of long-term morbidity and mortality. Despite its popularity in consumer devices, a lack of methodological standards and clinical validation remains a major impediment to step count being accepted as a valid clinical endpoint.

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An appealing strategy for treatment of metabolic disease in humans is activation of brown adipose tissue (BAT), a thermogenic organ best visualized through F-FDG PET/CT. BAT has been activated to varying degrees by mild cold exposure. However, this approach can cause undesirable stress, and there remains no consensus protocol.

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Objectives: Beta-3 adrenergic receptors (β3-AR) stimulate lipolysis and thermogenesis in white and brown adipose tissue (WAT and BAT). Obesity increases oxidative stress and inflammation that attenuate AT β3-AR signaling. The objective of this study was to test the hypothesis that the combination of the β3-AR agonist CL-316,243 (CL) and the antioxidant alpha-lipoic acid (ALA) would lower inflammation in diet-induced obesity (DIO) and improve β3-AR function.

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β3-Adrenergic receptors (β3-ARs) are the predominant regulators of rodent brown adipose tissue (BAT) thermogenesis. However, in humans, the physiological relevance of BAT and β3-AR remains controversial. Herein, using primary human adipocytes from supraclavicular neck fat and immortalized brown/beige adipocytes from deep neck fat from 2 subjects, we demonstrate that the β3-AR plays a critical role in regulating lipolysis, glycolysis, and thermogenesis.

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Functional status of patients is an important concept in clinical trials. It subsumes functional capacity, which is traditionally estimated by exercise tests, and functional performance, which is often estimated by questionnaires. Objectively measured physical activity by means of wearables devices containing accelerometers (PA) have recently been proposed as a novel and advantageous way to estimate physical status including capacity and performance.

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The current obesity pandemic results from a physiological imbalance in which energy intake chronically exceeds energy expenditure (EE), and prevention and treatment strategies remain generally ineffective. Approaches designed to increase EE have been informed by decades of experiments in rodent models designed to stimulate adaptive thermogenesis, a long-term increase in metabolism, primarily induced by chronic cold exposure. At the cellular level, thermogenesis is achieved through increased rates of futile cycling, which are observed in several systems, most notably the regulated uncoupling of oxidative phosphorylation from ATP generation by uncoupling protein 1, a tissue-specific protein present in mitochondria of brown adipose tissue (BAT).

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In the present study, we investigated whether melatonin would prevent nitric oxide (NO)-induced apoptotic death of PGT-beta immortalized pineal cells. To examine the protective effect of melatonin, cytotoxicity assay, DNA fragmentation analysis, caspase-3 activity assay, and Western blotting for caspase-3 and poly(ADP-ribose) polymerase (PARP) were performed. Treatment of cells with S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, was shown to induce apoptotic cell death in a dose-dependent manner, and pretreatment with melatonin (0.

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Background: Tissue factor located in the atherosclerotic plaque might cause the clinically significant thrombotic events associated with end-stage disease. It might also affect intimal area by increasing matrix accumulation and stimulating smooth muscle cell (SMC) migration and proliferation. To test this hypothesis, we overexpressed tissue factor in a rat model of the human fibrous plaque.

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The growth of neointima and neointimal smooth muscle cells in baboon polytetrafluoroethylene grafts is regulated by blood flow. Because neointimal smooth muscle cells express both platelet-derived growth factor receptor-alpha and -beta (PDGFR-alpha and -beta), we designed this study to test the hypothesis that inhibiting either PDGFR-alpha or PDGFR-beta with a specific mouse/human chimeric antibody will modulate flow-induced neointimal formation. Bilateral aortoiliac grafts and distal femoral arteriovenous fistulae were placed in 17 baboons.

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Elevated levels of plasminogen activator inhibitor type 1 (PAI-1) are found in advanced atherosclerotic plaque compared with normal vessel and may contribute to plaque progression and complications associated with plaque rupture. Increased expression of PAI-1 probably contributes to the thrombotic properties of advanced atherosclerotic plaque by impeding plasmin generation and degradation of fibrin. To test this hypothesis, we have deliberately created synthetic neointimas by seeding onto the denuded luminal surface of rat carotid arteries smooth muscle cells transduced with replication-defective retrovirus encoding rat PAI-1.

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Hemoglobin (Hb) is a toxic molecule responsible for the extreme lethality associated with experimental Escherichia coli peritonitis, but the mechanism has yet to be elucidated. Hb, but not globin, showed toxic effects in a live E. coli model but not in a model using killed E.

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Scrapie, one of the prion diseases, is a transmissible neurodegenerative disease of sheep and other animals. Clinical symptoms of prion diseases are characterized by a long latent period, followed by progressive ataxia, tremor, and death. To study the induction of neurodegeneration during scrapie infection, we have analyzed the activities of various antioxidant enzymes and mitochondrial enzymes in cerebral cortex, brain stem, and cerebellum of scrapie-infected hamsters.

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We have recently demonstrated that the blockade of matrix metalloproteinases by local overexpression of the intrinsic inhibitor tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) reduces intimal hyperplasia. We now report a major change in the elastin content of the intima of rat carotid arteries seeded with TIMP-1-overexpressing smooth muscle cells. To understand the mechanism responsible for elastin accumulation, synthesis and degradation of elastin in TIMP-1 and control cell-seeded rats were measured.

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Heparin is a complex glycosaminoglycan that inhibits vascular smooth muscle cell (SMC) growth in vitro and in vivo. To define the mechanism by which heparin exerts its antiproliferative effects, we asked whether heparin interferes with the activity of intracellular protein kinase C (PKC). The membrane-associated intracellular PKC activity increased following stimulation of cultured rat SMCs with fetal calf serum and was suppressed by heparin in a time- and dose-dependent manner.

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Arterial smooth muscle cells (SMCs) are in a quiescent growth state under normal physiological conditions, but they can be stimulated to proliferate and migrate from one tissue compartment to another if the vessel is injured. This response might require a selective and focal increase in tissue degradation, which might be mediated through the increased production of matrix metalloproteinases (MMPs). Blockade of MMP activity might therefore inhibit the SMC response to injury.

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The traditional method of antibody (Ab) generation requires repeated injections of antigen (Ag). We have developed an alternative method that allows an investigator to generate a polyclonal antiserum with only a cDNA in hand. We cloned a cDNA encoding the coding frame for baboon tissue inhibitor of matrix metalloproteinase-1 (TIMP-1).

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Smooth muscle cell (SMC) migration and proliferation and extracellular matrix remodeling are essential aspects of the arterial response to injury, vessel development, and atherogenesis. Matrix metalloproteinase (MMP) expression is associated with SMC proliferation and migration after arterial injury. To assess the role of MMPs in SMC proliferation and migration and intimal thickening, we measured the effect of the synthetic MMP inhibitor BB94 (Batimastat) on DNA synthesis and migration of SMCs in vitro as well as the formation of a neointima after balloon injury to the rat carotid artery.

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A baboon aortic smooth muscle cell (SMC) cDNA library was screened for the presence of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) by polymerase chain reaction (PCR); oligodeoxyribonucleotide primers corresponding to the coding frame of the known human TIMP-1 gene were used as primers. Sequencing of the PCR-amplified baboon cDNA demonstrated only eight single-nucleotide (nt) mismatches, when compared with the coding frame of human TIMP-1. The authenticity of the PCR-amplified TIMP-1 cDNA was further confirmed by clonal screening of the library with the PCR probe and sequencing of positive clones.

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