Publications by authors named "Michelle Sykes"

Importance: Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening complication of COVID-19 infection. Data on midterm outcomes are limited.

Objective: To characterize the frequency and time course of cardiac dysfunction (left ventricular ejection fraction [LVEF] <55%), coronary artery aneurysms (z score ≥2.

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Objectives: Greater congenital heart disease (CHD) complexity is associated with lower health-related quality of life (HRQOL). There are no data on the association between surgical and ICU factors and HRQOL in CHD survivors. This study assess the association between surgical and ICU factors and HRQOL in child and adolescent CHD survivors.

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Pulmonary vein stenosis (PVS) is associated with pulmonary hypertension (PH), but there is little information regarding the impact of PH on right ventricular (RV) systolic function and survival. We conducted a retrospective cohort study of our patients to explore this and other aspects of pulmonary hemodynamics with PVS. RV function was assessed using qualitative two-dimensional echocardiography.

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Objectives: Although pseudoaneurysm is an uncommon complication after right ventricle-to-pulmonary artery conduit placement, it has the potential to cause significant morbidity and mortality.

Methods: We performed a review of patients with pseudoaneurysms diagnosed at our institution in a 20-year period (from 1995 through 2015) and compared their clinical characteristics with a group of age- and sex-matched control patients.

Results: We found that younger age, smaller size, the diagnosis of tetralogy of Fallot, the use of a pulmonary homograft conduit, the presence of an unrestrictive ventricular septal defect after conduit placement, and having at least systemic right ventricular pressure were all more common in patients who had pseudoaneurysms develop.

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Bone loss due to osteoporosis or disuse such as in paraplegia or microgravity is a significant health problem. As a treatment for osteoporosis, brief exposure of intact animals or humans to low magnitude and high frequency (LMHF) mechanical loading has been shown to normalize and prevent bone loss. However, the underlying molecular changes and the target cells by which LMHF mechanical loading alleviate bone loss are not known.

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Weightlessness or microgravity of spaceflight induces bone loss due in part to decreased bone formation by unknown mechanisms. Due to difficulty in performing experiments in space, several ground-based simulators such as the Rotating Wall Vessel (RWV) and Random Positioning Machine (RPM) have become critical venues to continue studying space biology. However, these simulators have not been systematically compared to each other or to mechanical stimulating models.

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Exposure to microgravity causes bone loss in humans, and the underlying mechanism is thought to be at least partially due to a decrease in bone formation by osteoblasts. In the present study, we examined the hypothesis that microgravity changes osteoblast gene expression profiles, resulting in bone loss. For this study, we developed an in vitro system that simulates microgravity using the Random Positioning Machine (RPM) to study the effects of microgravity on 2T3 preosteoblast cells grown in gas-permeable culture disks.

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Atherosclerosis is now viewed as an inflammatory disease occurring preferentially in arterial regions exposed to disturbed flow conditions, including oscillatory shear stress (OS), in branched arteries. In contrast, the arterial regions exposed to laminar shear (LS) are relatively lesion-free. The mechanisms underlying the opposite effects of OS and LS on the inflammatory and atherogenic processes are not clearly understood.

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Caveolae are plasmalemmal domains enriched with cholesterol, caveolins, and signaling molecules. Endothelial cells in vivo are continuously exposed to shear conditions, and their caveolae density and location may be different from that of static cultured cells. Here, we show that chronic shear exposure regulates formation and localization of caveolae and caveolin-1 in bovine aortic endothelial cells (BAEC).

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Shear stress stimulates nitric oxide (NO) production by phosphorylating endothelial NO synthase (eNOS) at Ser(1179) in a phosphoinositide-3-kinase (PI3K)- and protein kinase A (PKA)-dependent manner. The eNOS has additional potential phosphorylation sites, including Ser(116), Thr(497), and Ser(635). Here, we studied these potential phosphorylation sites in response to shear, vascular endothelial growth factor (VEGF), and 8-bromocAMP (8-BRcAMP) in bovine aortic endothelial cells (BAEC).

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