91 research outputs found

    Do New Drugs Increase Life Expectancy? A Critique of a Manhattan Institute Paper

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    A recent study published by the Manhattan Institute “Why Has Longevity Increased More in Some States than in Others? The Role of Medical Innovation and Other Factors,” purported to show that the more rapid adoption of new drugs has substantial benefits in the form of increased life expectancy, higher productivity and lower non-drug health care expenditures. This study has been cited as evidence supporting the more rapid acceptance of new drugs in Medicaid, Medicare, and other public programs and has helped to shape public debate on the value of new drugs. This analysis questions the key conclusions of the study. It points out that the key statistical regressions appear to be misspecified, since they show anomalies such as a negative correlation between income growth and life expectancy and find no relationship between education and productivity growth. Methodological flaws addressed include lack of adjustment for infant mortality rates; inadequate proxy measures of health status; lack of adjustment for ages of individuals and other sociodemographic factors; inherent problems with the definition of drug age, or ‘vintage;’ and the failure to consider reverse causation as an obvious explanation for several findings. The Manhattan Institute study does not provide reliable evidence for favoring adoption of newer drugs in either public or private health care programs

    Knowledge gaps that hamper prevention and control of Mycobacterium avium subspecies paratuberculosis infection

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    In the last decades, many regional and country‐wide control programmes for Johne's disease (JD) were developed due to associated economic losses, or because of a possible association with Crohn's disease. These control programmes were often not successful, partly because management protocols were not followed, including the introduction of infected replacement cattle, because tests to identify infected animals were unreliable, and uptake by farmers was not high enough because of a perceived low return on investment. In the absence of a cure or effective commercial vaccines, control of JD is currently primarily based on herd management strategies to avoid infection of cattle and restrict within‐farm and farm‐to‐farm transmission. Although JD control programmes have been implemented in most developed countries, lessons learned from JD prevention and control programmes are underreported. Also, JD control programmes are typically evaluated in a limited number of herds and the duration of the study is less than 5 year, making it difficult to adequately assess the efficacy of control programmes. In this manuscript, we identify the most important gaps in knowledge hampering JD prevention and control programmes, including vaccination and diagnostics. Secondly, we discuss directions that research should take to address those knowledge gaps.http://wileyonlinelibrary.com/journal/tbed2019-05-01hj2018Veterinary Tropical Disease

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    An analysis of shaft/shaft seal interaction of a multiple disk centrifugal blood pump

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    Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references: p. 51-54.Issued also on microfiche from Lange Micrographics.A multiple disk centrifugal blood pump is in the early stages of development. As is the case with most pumps that are shaft driven, leakage problems around the shaft/shaft seal interface are of major interest. If leakage were to occur during or after implantation, potential events such as blood loss, clotting, blood damage, and/or infections could produce adverse effects for the patient. Because of these possibly adverse circumstances, materials and shafts are being evaluated to determine the most appropriate course to limit these effects. Teflon and Nylon were analyzed as potential shaft seal candidates with both a stainless steel shaft and a Melonite 9 coated shaft, the latter provided by Houston Unlimited Inc. Metal Processing in Chappell Hill, Texas. The materials and shafts were evaluated under four time durations (I 5, 3 0, 4 5, and 60 minutes), four rotation rates (800, 1000, 1200, and 1400 RPM), and two outer diameters (0.5" and 0.75"). The three main parameters evaluated were the inner diameter, the inner temperature, and the outer temperature. Statistical comparisons were computed for the shaft seal materials, the shafts, and the outer diameters along with the inner and outer temperatures. The results indicated that time and RPM had no significant effect on wear. Some unexpected information was produced. Most notable was that the coated shaft did not significantly reduce the amount of wear. This testing has provided enough information to suggest the need for either in vitro testing of the shaft seal or examining alternatives such as magnetic suspension or ferrofluidic sealing

    Clot embolization studies and computational framework for embolization in a canonical tube model

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    Abstract Despite recent advances in the development of computational methods of modeling thrombosis, relatively little effort has been made in developing methods of modeling blood clot embolization. Such a model would provide substantially greater understanding of the mechanics of embolization, as in-vitro and in-vivo characterization of embolization is difficult. Here, a method of computationally simulating embolization is developed. Experiments are performed of blood clots formed in a polycarbonate tube, where phosphate-buffered saline is run through the tube at increasing flow rates until the clot embolizes. The experiments revealed embolization can be initiated by leading edge and trailing edge detachment or by non-uniform detachment. Stress-relaxation experiments are also performed to establish values of constitutive parameters for subsequent simulations. The embolization in the tube is reproduced in silico using a multiphase volume-of-fluid approach, where the clot is modeled as viscoelastic. By varying the constitutive parameters at the wall, embolization can be reproduced in-silico at varying flow rates, and a range of constitutive parameters fitting the experiments is reported. Here, the leading edge embolization is simulated at flow rates consistent with the experiments demonstrating excellent agreement in this specific behavior
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