Publications by authors named "Robert C Long"

Heart failure (HF) has emerged as a global epidemic and it affects about 6 million adults in the US. HF medical treatment, as recommended in guidelines, significantly improves survival and quality of life; however, the mortality burden of HF remains high. For decades, treatment has been guided, mainly by symptoms, leading to undertreatment in a range of settings.

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Background: Left ventricular false tendons (LVFTs) are chord-like structures that traverse the LV cavity and are generally considered to be benign. However, they have been associated with arrhythmias, LV hypertrophy and LV dilation in some small studies. We hypothesize that LVFTs are associated with LV structural and functional changes assessed by echocardiography.

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With available MRI techniques, primary and metastatic liver cancers that are associated with high mortality rates and poor treatment responses are only diagnosed at late stages, due to the lack of highly sensitive contrast agents without Gd(3+) toxicity. We have developed a protein contrast agent (ProCA32) that exhibits high stability for Gd(3+) and a 10(11)-fold greater selectivity for Gd(3+) over Zn(2+) compared with existing contrast agents. ProCA32, modified from parvalbumin, possesses high relaxivities (r1/r2: 66.

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Cardiovascular disease is the leading cause of death generally and the most common cause of death during pregnancy in industrialized countries. Improvement in early diagnosis and treatment of congenital heart disease has increased the number of women with such conditions reaching reproductive age. The growing prevalence of diabetes, hypertension, obesity, hyperlipidemia, and metabolic syndrome has concurrently added to the population of pregnant women with acquired heart disease, including coronary artery disease.

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Objective: Current understanding of shear-sensitive signaling pathways has primarily been studied in vitro largely because of a lack of adequate in vivo models. Our objective was to develop a simple and well-characterized murine aortic coarctation model to acutely alter the hemodynamic environment in vivo and test the hypothesis that endothelial inflammatory protein expression is acutely upregulated in vivo by low-magnitude oscillatory wall shear stress (WSS).

Methods And Results: Our model uses the shape memory response of nitinol clips to reproducibly induce an aortic coarctation and allow subsequent focal control over WSS in the aorta.

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Unless chemically crosslinked, matrix proteins, such as collagen or silk, display a limited lifetime in vivo with significant degradation observed over a period of weeks. Likewise, amphiphilic peptides, lipopeptides, or glycolipids that self-assemble through hydrophobic interactions to form thin films, fiber networks, or vesicles do not demonstrate in vivo biostability beyond a few days. We report herein that a self-assembling, recombinant elastin-mimetic triblock copolymer elicited minimal inflammatory response and displayed robust in vivo stability for periods exceeding 1 year, in the absence of either chemical or ionic crosslinking.

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Abdominal aortic aneurysms (AAA) localize in the infrarenal aorta in humans, while they are found in the suprarenal aorta in mouse models. It has been shown previously that humans experience a reversal of flow during early diastole in the infrarenal aorta during each cardiac cycle. This flow reversal causes oscillatory wall shear stress (OWSS) to be present in the infrarenal aorta of humans.

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Reporter gene-based magnetic resonance imaging (MRI) offers unique insights into behavior of cells after transplantation, which could significantly benefit stem cell research and translation. Several candidate MRI reporter genes, including one that encodes for iron storage protein ferritin, have been reported, and their potential applications in embryonic stem (ES) cell research have yet to be explored. We have established transgenic mouse ES (mES) cell lines carrying human ferritin heavy chain (FTH) as a reporter gene and succeeded in monitoring the cell grafts in vivo using T(2)-weighted MRI sequences.

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Objective: To determine whether dietary fatty acids affect indicators of insulin sensitivity, plasma insulin and lipid concentrations, and lipid accumulation in muscle cells in lean and obese cats.

Animals: 28 neutered adult cats.

Procedure: IV glucose tolerance tests and magnetic resonance imaging were performed before (lean phase) and after 21 weeks of ad libitum intake of either a diet high in omega-3 polyunsaturated fatty acids (3-PUFAs; n = 14) or high in saturated fatty acids (SFAs; 14).

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