1,086 research outputs found

    Gentamicin Pharmacokinetics in Term Neonates Receiving Extracorporeal Membrane Oxygenation

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90148/1/j.1875-9114.1992.tb02667.x.pd

    Shared behavioral mechanisms underlie <i>C. elegans</i> aggregation and swarming

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    In complex biological systems, simple individual-level behavioral rules can give rise to emergent group-level behavior. While collective behavior has been well studied in cells and larger organisms, the mesoscopic scale is less understood, as it is unclear which sensory inputs and physical processes matter a priori. Here, we investigate collective feeding in the roundworm C. elegans at this intermediate scale, using quantitative phenotyping and agent-based modeling to identify behavioral rules underlying both aggregation and swarming—a dynamic phenotype only observed at longer timescales. Using fluorescence multi-worm tracking, we quantify aggregation in terms of individual dynamics and population-level statistics. Then we use agent-based simulations and approximate Bayesian inference to identify three key behavioral rules for aggregation: cluster-edge reversals, a density-dependent switch between crawling speeds, and taxis towards neighboring worms. Our simulations suggest that swarming is simply driven by local food depletion but otherwise employs the same behavioral mechanisms as the initial aggregation

    Differential effect of body mass index on pediatric heart transplant outcomes based on diagnosis

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    The impact of nutritional status on HT x waitlist mortality in children is unknown, and there are conflicting data regarding the role of nutrition in post‐ HT x survival. This study examined the influence of nutrition on waitlist and post‐ HT x outcomes in children. Children 2–18 yr listed for HT x from 1997 to 2011 were identified from the OPTN database and stratified by BMI percentile. Multivariable logistic regression evaluated the influence of BMI on waitlist mortality. Cox proportional hazard regression assessed the impact of BMI on post‐ HT x mortality. When all 2712 patients were analyzed, BMI did not impact waitlist, one‐, or five‐yr mortality. However, when stratified by diagnosis, BMI  > 95% ( AOR 1.96; 95% CI 1.24, 3.09) and BMI   95% and BMI  < 1% are independent risk factors for waitlist mortality in patients with CM, but not CHD . This suggests differing risk factors based on disease etiology, and an individualized approach to risk assessment based on diagnosis may be warranted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108679/1/petr12352.pd

    Convergent evolution of pregnancy-specific glycoproteins in human and horse

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    Pregnancy-specific glycoproteins (PSGs) are members of the carcinoembryonic antigen cell adhesion molecule (CEACAM) family that are secreted by trophoblast cells. PSGs may modulate immune, angiogenic and platelet responses during pregnancy. Until now, PSGs are only found in species that have a highly invasive (hemochorial) placentation including humans, mice and rats. Surprisingly, analyzing the CEACAM gene family of the horse, which has a non-invasive epitheliochorial placenta, with the exception of the transient endometrial cups, we identified equine CEACAM family members that seem to be related to PSGs of rodents and primates. We identified seven genes that encode secreted PSG-like CEACAMs. Phylogenetic analyses indicate that they evolved independently from an equine CEACAM1-like ancestor rather than from a common PSG-like ancestor with rodents and primates. Significantly, expression of PSG-like genes (CEACAM44, CEACAM48, CEACAM49 and CEACAM55) was found in non-invasive as well as invasive trophoblast cells such as purified chorionic girdle cells and endometrial cup cells. Chorionic girdle cells are highly invasive trophoblast cells that invade the endometrium of the mare where they form endometrial cups and are in close contact with maternal immune cells. Therefore, the microenvironment of invasive equine trophoblast cells has striking similarities to the microenvironment of trophoblast cells in hemochorial placentas, suggesting that equine PSG-like CEACAMs and rodent and primate PSGs have undergone convergent evolution. This is supported by our finding that equine PSG-like CEACAM49 exhibits similar activity to certain rodent and human PSGs in a functional assay of platelet–fibrinogen binding. Our results have implications for understanding the evolution of PSGs and their functions in maternal–fetal interactions

    Comparison of solitary and collective foraging strategies of Caenorhabditis elegans in patchy food distributions

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    Collective foraging has been shown to benefit organisms in environments where food is patchily distributed, but whether this is true in the case where organisms do not rely on long range communications to coordinate their collective behaviour has been understudied. To address this question, we use the tractable laboratory model organism Caenorhabditis elegans, where a social strain (npr-1 mutant) and a solitary strain (N2) are available for direct comparison of foraging strategies. We first developed an on-lattice minimal model for comparing collective and solitary foraging strategies, finding that social agents benefit from feeding faster and more efficiently simply due to group formation. Our laboratory foraging experiments with npr-1 and N2 worm populations, however, show an advantage for solitary N2 in all food distribution environments that we tested. We incorporated additional strain43 specific behavioural parameters of npr-1 and N2 worms into our model and computationally identified N2’s higher feeding rate to be the key factor underlying its advantage, without which it is possible to recapitulate the advantage of collective foraging in patchy environments. Our work highlights the theoretical advantage of collective foraging due to group formation alone without long-range interactions, and the valuable role of modelling to guide experiments

    The Resource Theory of Quantum States Out of Thermal Equilibrium

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    The ideas of thermodynamics have proved fruitful in the setting of quantum information theory, in particular the notion that when the allowed transformations of a system are restricted, certain states of the system become useful resources with which one can prepare previously inaccessible states. The theory of entanglement is perhaps the best-known and most well-understood resource theory in this sense. Here we return to the basic questions of thermodynamics using the formalism of resource theories developed in quantum information theory and show that the free energy of thermodynamics emerges naturally from the resource theory of energy-preserving transformations. Specifically, the free energy quantifies the amount of useful work which can be extracted from asymptotically-many copies of a quantum system when using only reversible energy-preserving transformations and a thermal bath at fixed temperature. The free energy also quantifies the rate at which resource states can be reversibly interconverted asymptotically, provided that a sublinear amount of coherent superposition over energy levels is available, a situation analogous to the sublinear amount of classical communication required for entanglement dilution.Comment: 4.5 pages main text, 12 pages appendix; v3: improvements to presentation of the main resul

    A Comparison of Synovex ONE® Alone to Synovex Choice® Followed by Synovex Plus® as Implant Strategies for Finishing Heifers

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    A commercial feedlot study utilizing 1,737 crossbred heifers (initial BW 690 lb) compared the effect of two implant strategies [Synovex ONE Feedlot (day 0) or Synovex Choice (day 0) followed by Synovex Plus (day 95)] on performance and carcass characteristics. No differences were observed in carcass weight, final body weight, or gain, but heifers implanted with Synovex ONE Feedlot had slightly greater feed conversion and greater intake than heifers implanted using Synovex Choice/Synovex Plus. Heifers implanted with Synovex Choice/Synovex Plus had lower marbling score and yield grade, higher dressing percentage, and greater loin muscle area compared to heifers implanted with Synovex ONE Feedlot. Cattle implanted with Synovex ONE Feedlot showed a tendency for better quality grading compared to heifers implanted with Synovex Choice/Synovex Plus. These data suggest that implanting heifers with Synovex ONE Feedlot gives comparable growth to heifers implanted with Synovex Choice followed by Synovex Plus, with some changes in fatness when fed equal days

    Infectious Complications of Ventricular Assist Device Use in Children in the US: Data from the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs)

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    Background Infections are frequent in pediatric ventricular assist device (VAD) patients. In this study we aimed to describe infections in durable VAD patients reported to Pedimacs. Methods Durable VAD data from the Pedimacs registry (September 19, 2012 to December 31, 2015) were analyzed. Infections were described with standard descriptive statistics, Kaplan–Meier analysis and competing outcomes analysis. Results There were 248 implants in 222 patients, with a mean age and a median follow-up of 11 ± 6.4 years and 2.4 patient-months (<1 day to 2.6 years), respectively. Device types were pulsatile flow (PF) in 91 (41%) patients and continuous flow (CF) in 131 (59%) patients. PF patients were younger (4 ± 4 vs 14 ± 4 years; p < 0.0001) and were more likely to have congenital heart disease (25% vs 12%; p = 0.03), prior surgery (53% vs 26%; p < 0.0001) and prior extracorporeal membrane oxygenation (24% vs 7%; p = 0.0003). Infection accounted for 17% (96 of 564) of the reported adverse events (AEs). A non-device infection was most common (51%), followed by sepsis (24%), external pump component infection (20%) and internal pump component infection (5%). Most infections were bacterial (73%) and required intravenous therapy only (77%). The risk of infection in the constant phase was higher in patients with a history of prior infection and in patients with a history of a non-infectious major AEs. Survival was lower after infection only in CF patients (p = 0.008). Conclusions Infection was the most common AE after pediatric VAD implantation. Non-device infections were most common. The best predictor of a future infection was a past infection. CF patients have higher risk of death after an infection

    The anaphylatoxins C3a and C5a are vasodilators in the canine coronary vasculature in vitro and in vivo

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    The effect of complement fragments on coronary blood flow in vivo and the contraction of coronary arteries in vitro was determined. In pentobarbital anesthetized dogs, intraarterial bolus injection of C3a and C5a, zymosan-activated serum and methylcholine in the coronary vascular bed caused transient and dose-dependent increases in coronary blood flow. Similar increases were obtained with 25 μg of C3a (104±13%, n =5) and 0.1 μg of methylcholine (102±4%, n =3). Smaller, increases in blood flow were elicited by 25 μg of C5a (41±18%, n =4) and 0.2 ml, of zymosan-activated serum (48±5%, n =4). None of these responses were associated, with significant changes in left ventricular contractile force measured with a strain gauge, arterial blood pressure, and heart rate. C3a dilated the coronary vascular bed in conscious dogs with an activity equal to or greater than that observed in anesthetized dogs. Isolated canine coronary arteries that were precontracted with serotonin relaxed in response to C3a, whether or not the endothelium was intact. Overall these data suggest that physiologically high doses of anaphylactic complement fragments vasodilate the canine coronary circulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45056/1/11_2005_Article_BF01988727.pd
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