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Search Results: 1 - 10 of 206648 matches for " Alan P. Kypson "
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Robotic Applications in Cardiac Surgery
Alan P. Kypson,W. Randolph Chitwood Jr.
International Journal of Advanced Robotic Systems , 2008,
Abstract: Traditionally, cardiac surgery has been performed through a median sternotomy, which allows the surgeon generous access to the heart and surrounding great vessels. As a paradigm shift in the size and location of incisions occurs in cardiac surgery, new methods have been developed to allow the surgeon the same amount of dexterity and accessibility to the heart in confined spaces and in a less invasive manner. Initially, long instruments without pivot points were used, however, more recent robotic telemanipulation systems have been applied that allow for improved dexterity, enabling the surgeon to perform cardiac surgery from a distance not previously possible. In this rapidly evolving field, we review the recent history and clinical results of using robotics in cardiac surgery.
Robotic Applications in Cardiac Surgery
Alan P. Kypson,W. Randolph Chitwood Jr
Computer Science , 2004,
Abstract: Traditionally, cardiac surgery has been performed through a median sternotomy, which allows the surgeon generous access to the heart and surrounding great vessels. As a paradigm shift in the size and location of incisions occurs in cardiac surgery, new methods have been developed to allow the surgeon the same amount of dexterity and accessibility to the heart in confined spaces and in a less invasive manner. Initially, long instruments without pivot points were used, however, more recent robotic telemanipulation systems have been applied that allow for improved dexterity, enabling the surgeon to perform cardiac surgery from a distance not previously possible. In this rapidly evolving field, we review the recent history and clinical results of using robotics in cardiac surgery.
Grand Challenge: Understanding Survival Paradoxes in Epidemiology
Jimmy T. Efird,Wesley T. O’Neal,Alan P. Kypson
Frontiers in Public Health , 2013, DOI: 10.3389/fpubh.2013.00003
Abstract:
The Effect of Race and Chronic Obstructive Pulmonary Disease on Long-Term Survival after Coronary Artery Bypass Grafting
Jimmy T. Efird,Wesley T. O’Neal,Jason B. O’Neal,Alan P. Kypson
Frontiers in Public Health , 2013, DOI: 10.3389/fpubh.2013.00004
Abstract: Background: Chronic obstructive pulmonary disease (COPD) is a known predictor of decreased long-term survival after coronary artery bypass grafting (CABG). Differences in survival by race have not been examined.
Quantum dot labeling of mesenchymal stem cells
Barbara J Muller-Borer, Maria C Collins, Philip R Gunst, Wayne E Cascio, Alan P Kypson
Journal of Nanobiotechnology , 2007, DOI: 10.1186/1477-3155-5-9
Abstract: A dose-response to QDs in rat bone marrow MSCs was assessed in Control (no-QDs), Low concentration (LC, 5 nmol/L) and High concentration (HC, 20 nmol/L) groups. QD yield and retention, MSC survival, proinflammatory cytokines, proliferation and DNA damage were evaluated in MSCs, 24 -120 hrs post QD labeling. In addition, functional integration of QD labeled MSCs in an in vitro cardiomyocyte co-culture was assessed. A dose-dependent effect was measured with increased yield in HC vs. LC labeled MSCs (93 ± 3% vs. 50% ± 15%, p < 0.05), with a larger number of QD aggregates per cell in HC vs. LC MSCs at each time point (p < 0.05). At 24 hrs >90% of QD labeled cells were viable in all groups, however, at 120 hrs increased apoptosis was measured in HC vs. Control MSCs (7.2% ± 2.7% vs. 0.5% ± 0.4%, p < 0.05). MCP-1 and IL-6 levels doubled in HC MSCs when measured 24 hrs after QD labeling. No change in MSC proliferation or DNA damage was observed in QD labeled MSCs at 24, 72 and 120 hrs post labeling. Finally, in a cardiomyocyte co-culture QD labeled MSCs were easy to locate and formed functional cell-to-cell couplings, assessed by dye diffusion.Fluorescent QDs label MSC effectively in an in vitro co-culture model. QDs are easy to use, show a high yield and survival rate with minimal cytotoxic effects. Dose-dependent effects suggest limiting MSC QD exposure.Cell transplantation therapy using adult derived bone marrow mesenchymal stem cells (MSCs) is currently being investigated as a potential therapy to treat injured heart tissue [1,2]. Transplanted MSCs are expected to engraft, differentiate and remodel in response to the surrounding cardiac microenvironment resulting in tissue regeneration and functional repair. The mechanisms underlying MSC engraftment and electrical and mechanical integration with host cardiac tissue are not understood. In part, this is due to limited methods to track MSCs in vivo, precluding long-term functional studies of transplanted cells. Current met
Discharge β-Blocker Use and Race after Coronary Artery Bypass Grafting
Wesley T. O’Neal,Jimmy T. Efird,Stephen W. Davies,Jason B. O’Neal,T. Bruce Ferguson,Alan P. Kypson
Frontiers in Public Health , 2014, DOI: 10.3389/fpubh.2014.00094
Abstract: Introduction: The use of discharge β-blockers after cardiac surgery is associated with a long-term mortality benefit. β-Blockers have been suggested to be less effective in black cardiovascular patients compared with whites. To date, racial differences in the long-term survival of coronary artery bypass grafting (CABG) patients who receive β-blockers at discharge have not been examined.
Racial Differences in Survival among Hemodialysis Patients after Coronary Artery Bypass Grafting
Jimmy T. Efird,Wesley T. O'Neal,Paul Bolin,Stephen W. Davies,Jason B. O'Neal,Curtis A. Anderson,T. Bruce Ferguson,W. Randolph Chitwood,Alan P. Kypson
International Journal of Environmental Research and Public Health , 2013, DOI: 10.3390/ijerph10094175
Abstract: The aim of this study was to examine racial differences in long-term survival among hemodialysis patients after coronary artery bypass grafting (CABG). To our knowledge this has not been previously addressed in the literature. Black and white hemodialysis patients undergoing first-time, isolated CABG procedures between 1992 and 2011 were compared. Survival probabilities were computed using the Kaplan-Meier product-limit method and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. A total of 207 (2%) patients were on hemodialysis at the time of CABG. White (n = 80) hemodialysis patients had significantly decreased 5-year survival compared with black (n = 127) patients (adjusted HR = 1.9, 95% CI = 1.2–2.8). Our finding provides useful outcome information for surgeons, primary care providers, and their patients.
Immunopathology and Immunogenetics of Allergic Bronchopulmonary Aspergillosis
Alan P. Knutsen
Journal of Allergy , 2011, DOI: 10.1155/2011/785983
Abstract: Allergic bronchopulmonary aspergillosis (ABPA) is a Th2 hypersensitivity lung disease in response to Aspergillus fumigatus that affects asthmatic and cystic fibrosis (CF) patients. Sensitization to A. fumigatus is common in both atopic asthmatic and CF patients, yet only 1%–2% of asthmatic and 7%–9% of CF patients develop ABPA. ABPA is characterized by wheezing and pulmonary infiltrates which may lead to pulmonary fibrosis and/or bronchiectasis. The inflammatory response is characterized by Th2 responses to Aspergillus allergens, increased serum IgE, and eosinophilia. A number of genetic risks have recently been identified in the development of ABPA. These include HLA-DR and HLA-DQ, IL-4 receptor alpha chain (IL-4RA) polymorphisms, IL-10 ?1082GA promoter polymorphisms, surfactant protein A2 (SP-A2) polymorphisms, and cystic fibrosis transmembrane conductance regulator gene (CFTR) mutations. The studies indicate that ABPA patients are genetically at risk to develop skewed and heightened Th2 responses to A. fumigatus antigens. These genetic risk studies and their consequences of elevated biologic markers may aid in identifying asthmatic and CF patients who are at risk to the development of ABPA. Furthermore, these studies suggest that immune modulation with medications such as anti-IgE, anti-IL-4, and/or IL-13 monoclonal antibodies may be helpful in the treatment of ABPA. 1. Introduction Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity lung disease due to bronchial colonization by Aspergillus fumigatus that occurs in susceptible patients with asthma and cystic fibrosis (CF). The first published description of ABPA as an entity came from the United Kingdom in 1952 [1], while the first cases in the United States were reported a decade later [2, 3]. ABPA affects approximately 1%–2% of asthmatic patients and 7%–9% of CF patients [4–6]. If unrecognized or poorly treated, ABPA leads to airway destruction, bronchiectasis, and/or pulmonary fibrosis, resulting in significant morbidity and mortality. The diagnosis of ABPA is based on clinical and immunologic reactivity to A. fumigatus. The minimal criteria required for the diagnosis of ABPA are: (1) asthma or cystic fibrosis with deterioration of lung function, for example, wheezing, (2) immediate Aspergillus skin test reactivity, (3) total serum IgE ≥ 1000?IU/mL, (4) elevated Aspergillus specific IgE and IgG antibodies, and (5) chest radiographic infiltrates. Additional criteria may include peripheral blood eosinophilia, Aspergillus serum precipitating antibodies, central bronchiectasis, and
Formation of Giant Planets by Disk Instability on Wide Orbits Around Protostars with Varied Masses
Alan P. Boss
Physics , 2011, DOI: 10.1088/0004-637X/731/1/74
Abstract: Doppler surveys have shown that more massive stars have significantly higher frequencies of giant planets inside $\sim$ 3 AU than lower mass stars, consistent with giant planet formation by core accretion. Direct imaging searches have begun to discover significant numbers of giant planet candidates around stars with masses of $\sim$ 1 $M_\odot$ to $\sim$ 2 $M_\odot$ at orbital distances of $\sim$ 20 AU to $\sim$ 120 AU. Given the inability of core accretion to form giant planets at such large distances, gravitational instabilities of the gas disk leading to clump formation have been suggested as the more likely formation mechanism. Here we present five new models of the evolution of disks with inner radii of 20 AU and outer radii of 60 AU, for central protostars with masses of 0.1, 0.5, 1.0, 1.5, and 2.0 $M_\odot$, in order to assess the likelihood of planet formation on wide orbits around stars with varied masses. The disk masses range from 0.028 $M_\odot$ to 0.21 $M_\odot$, with initial Toomre $Q$ stability values ranging from 1.1 in the inner disks to $\sim 1.6$ in the outer disks. These five models show that disk instability is capable of forming clumps on time scales of $\sim 10^3$ yr that, if they survive for longer times, could form giant planets initially on orbits with semimajor axes of $\sim$ 30 AU to $\sim$ 70 AU and eccenticities of $\sim$ 0 to $\sim$ 0.35, with initial masses of $\sim 1 M_{Jup}$ to $\sim 5 M_{Jup}$, around solar-type stars, with more protoplanets forming as the mass of the protostar (and protoplanetary disk) are increased. In particular, disk instability appears to be a likely formation mechanism for the HR 8799 gas giant planetary system.
Evolution of the Solar Nebula. IX. Gradients in the Spatial Heterogeneity of the Short-Lived Radioisotopes $^{60}$Fe and $^{26}$Al and the Stable Oxygen Isotopes
Alan P. Boss
Physics , 2011, DOI: 10.1088/0004-637X/739/2/61
Abstract: Short-lived radioisotopes (SLRI) such as $^{60}$Fe and $^{26}$Al were likely injected into the solar nebula in a spatially and temporally heterogeneous manner. Marginally gravitationally unstable (MGU) disks, of the type required to form gas giant planets, are capable of rapid homogenization of isotopic heterogeneity as well as of rapid radial transport of dust grains and gases throughout a protoplanetary disk. Two different types of new models of a MGU disk in orbit around a solar-mass protostar are presented. The first set has variations in the number of terms in the spherical harmonic solution for the gravitational potential, effectively studying the effect of varying the spatial resolution of the gravitational torques responsible for MGU disk evolution. The second set explores the effects of varying the initial minimum value of the Toomre $Q$ stability parameter, from values of 1.4 to 2.5, i.e., toward increasingly less unstable disks. The new models show that the basic results are largely independent of both sets of variations. MGU disk models robustly result in rapid mixing of initially highly heterogeneous distributions of SLRIs to levels of $\sim$ 10% in both the inner ($<$ 5 AU) and outer ($>$ 10 AU) disk regions, and to even lower levels ($\sim$ 2%) in intermediate regions, where gravitational torques are most effective at mixing. These gradients should have cosmochemical implications for the distribution of SLRIs and stable oxygen isotopes contained in planetesimals (e.g., comets) formed in the giant planet region ($\sim$ 5 to $\sim$ 10 AU) compared to those formed elsewhere.
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