1,703 research outputs found

    John H. Gibbon, Jr., M.D.: surgical innovator, pioneer, and inspiration.

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    Throughout history there have been many discoveries that have changed the world, including Albert Einstein’s theory of relativity, Alexander Graham Bell’s telephone, and Jack Kilby and Robert Noyce’s microchip. There are a few analogous contributions that have been made in medicine: Sir Alexander’s discovery of penicillin, Lister’s principles of antiseptic technique, Salk and Sabin’s vaccines for polio, as well as numerous others. These innovative thinkers all had two factors in common. First, they were pioneers who faced problems that had no solutions at the time and who refused to accept the status quo in the face of great scrutiny and resistance. Second, their contributions would forever change the world. In 1930, a profound experience with a patient would forever change Dr. John H. Gibbon, Jr. and stimulate an idea to create a device that at the time sounded audacious and impossible. His device would temporarily take the role of both the heart and lungs to make repairs inside the heart or the great vessels. Twentythree years later, Dr. Gibbon used his machine to perform the first successful bypass-assisted open heart surgery

    Impact of Obesity on Perioperative Morbidity and Mortality Following Pancreaticoduodenectomy

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    Background: Obesity has been implicated as a risk factor for perioperative and postoperative complications. The aim of this study was determine the impact of obesity on morbidity and mortality in patients undergoing pancreaticoduodenectomy (PD). Study Design: Between January 2000 and July 2007, 262 patients underwent PD at Thomas Jefferson University Hospital (TJUH), of whom 240 had complete data, including body mass index (BMI) for analysis. Data on BMI, preoperative parameters, operative details, and post-operative course were collected. Patients were categorized as obese (BMI \u3e30 kg/m2), overweight (25≤BMI\u3c30), or normal weight (BMI\u3c25). Complications were graded according to previous published scales. Other endpoints included length of postoperative hospital stay, blood loss, and operative duration. Analyses were performed using univariate and multivariable models. Results: There were 103 (42.9%) normal weight, 71 (29.6%) overweight and 66 (27.5%) obese patients. There were 5 perioperative deaths (2.1%) with no differences across BMI categories. A significant difference in median operative duration and blood loss between obese and normal weight patients was identified (439vs. 362.5minutes, p= 0.0004; 650 vs. 500 ml, p=0.0139). Furthermore, median length of stay was marginally significantly longer for by BMI (9.5 vs. 8 days, p=0.095). While there were no significant differences in superficial wound infections, obese patients did have an increased rate of serious complications compared to normal weight patients (24.2% vs. 13.6%, respectively; p=0.10). Conclusions: Obese patients undergoing PD have a significantly increased blood loss and longer operative time, but do not have a significantly increased length of postoperative hospital stay or rate of serious complications. These findings should be considered when assessing patients for operation and when counseling patients regarding operative risk, but do not preclude obese individuals from undergoing definitive pancreatic surgery

    Cell-Free DNA and Active Rejection in Kidney Allografts

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    Histologic analysis of the allograft biopsy specimen is the standard method used to differentiate rejection from other injury in kidney transplants. Donor-derived cell-free DNA (dd-cfDNA) is a noninvasive test of allograft injury that may enable more frequent, quantitative, and safer assessment of allograft rejection and injury status. To investigate this possibility, we prospectively collected blood specimens at scheduled intervals and at the time of clinically indicated biopsies. In 102 kidney recipients, we measured plasma levels of dd-cfDNA and correlated the levels with allograft rejection status ascertained by histology in 107 biopsy specimens. The dd-cfDNA level discriminated between biopsy specimens showing any rejection (T cell-mediated rejection or antibody-mediated rejection [ABMR]) and controls (no rejection histologically), P1% indicate a probability of active rejection

    Integrated Assessment of Genomic Correlates of Protein Evolutionary Rate

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    Rates of evolution differ widely among proteins, but the causes and consequences of such differences remain under debate. With the advent of high-throughput functional genomics, it is now possible to rigorously assess the genomic correlates of protein evolutionary rate. However, dissecting the correlations among evolutionary rate and these genomic features remains a major challenge. Here, we use an integrated probabilistic modeling approach to study genomic correlates of protein evolutionary rate in Saccharomyces cerevisiae. We measure and rank degrees of association between (i) an approximate measure of protein evolutionary rate with high genome coverage, and (ii) a diverse list of protein properties (sequence, structural, functional, network, and phenotypic). We observe, among many statistically significant correlations, that slowly evolving proteins tend to be regulated by more transcription factors, deficient in predicted structural disorder, involved in characteristic biological functions (such as translation), biased in amino acid composition, and are generally more abundant, more essential, and enriched for interaction partners. Many of these results are in agreement with recent studies. In addition, we assess information contribution of different subsets of these protein properties in the task of predicting slowly evolving proteins. We employ a logistic regression model on binned data that is able to account for intercorrelation, non-linearity, and heterogeneity within features. Our model considers features both individually and in natural ensembles (“meta-features”) in order to assess joint information contribution and degree of contribution independence. Meta-features based on protein abundance and amino acid composition make strong, partially independent contributions to the task of predicting slowly evolving proteins; other meta-features make additional minor contributions. The combination of all meta-features yields predictions comparable to those based on paired species comparisons, and approaching the predictive limit of optimal lineage-insensitive features. Our integrated assessment framework can be readily extended to other correlational analyses at the genome scale

    LSST Science Book, Version 2.0

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    A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

    Iranian staff nurses' views of their productivity and human resource factors improving and impeding it: a qualitative study

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    BACKGROUND: Nurses, as the largest human resource element of health care systems, have a major role in providing ongoing, high-quality care to patients. Productivity is a significant indicator of professional development within any professional group, including nurses. The human resource element has been identified as the most important factor affecting productivity. This research aimed to explore nurses' perceptions and experiences of productivity and human resource factors improving or impeding it. METHOD: A qualitative approach was used to obtain rich data; open, semi-structured interviews were also conducted. The sampling was based on the maximum variant approach; data analysis was carried out by content analysis, with the constant comparative method. RESULTS: Participants indicated that human resources issues are the most important factor in promoting or impeding their productivity. They suggested that the factors influencing effectiveness of human resource elements include: systematic evaluation of staff numbers; a sound selection process based on verifiable criteria; provision of an adequate staffing level throughout the year; full involvement of the ward sister in the process of admitting patients; and sound communication within the care team. Paying attention to these factors creates a suitable background for improved productivity and decreases negative impacts of human resource shortages, whereas ignoring or interfering with them would result in lowering of nurses' productivity. CONCLUSION: Participants maintained that satisfactory human resources can improve nurses' productivity and the quality of care they provide; thereby fulfilling the core objective of the health care system

    Evidence for the additions of clustered interacting nodes during the evolution of protein interaction networks from network motifs

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    <p>Abstract</p> <p>Background</p> <p>High-throughput screens have revealed large-scale protein interaction networks defining most cellular functions. How the proteins were added to the protein interaction network during its growth is a basic and important issue. Network motifs represent the simplest building blocks of cellular machines and are of biological significance.</p> <p>Results</p> <p>Here we study the evolution of protein interaction networks from the perspective of network motifs. We find that in current protein interaction networks, proteins of the same age class tend to form motifs and such co-origins of motif constituents are affected by their topologies and biological functions. Further, we find that the proteins within motifs whose constituents are of the same age class tend to be densely interconnected, co-evolve and share the same biological functions, and these motifs tend to be within protein complexes.</p> <p>Conclusions</p> <p>Our findings provide novel evidence for the hypothesis of the additions of clustered interacting nodes and point out network motifs, especially the motifs with the dense topology and specific function may play important roles during this process. Our results suggest functional constraints may be the underlying driving force for such additions of clustered interacting nodes.</p
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