485 research outputs found

    Evolution of a neuroprotective function of central nervous system myelin

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    The central nervous system (CNS) of terrestrial vertebrates underwent a prominent molecular change when a tetraspan membrane protein, myelin proteolipid protein (PLP), replaced the type I integral membrane protein, P0, as the major protein of myelin. To investigate possible reasons for this molecular switch, we genetically engineered mice to express P0 instead of PLP in CNS myelin. In the absence of PLP, the ancestral P0 provided a periodicity to mouse compact CNS myelin that was identical to mouse PNS myelin, where P0 is the major structural protein today. The PLP–P0 shift resulted in reduced myelin internode length, degeneration of myelinated axons, severe neurological disability, and a 50% reduction in lifespan. Mice with equal amounts of P0 and PLP in CNS myelin had a normal lifespan and no axonal degeneration. These data support the hypothesis that the P0–PLP shift during vertebrate evolution provided a vital neuroprotective function to myelin-forming CNS glia

    Estrogen Receptor Hormone Agonists Limit Trauma Hemorrhage Shock-Induced Gut and Lung Injury in Rats

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    Acute lung injury (ALI) and the development of the multiple organ dysfunction syndrome (MODS) is a major cause of death in trauma patients. Earlier studies in trauma hemorrhagic shock (T/HS) have documented that splanchnic ischemia leading to gut inflammation and loss of barrier function is an initial triggering event that leads to gut-induced ARDS and MODS. Since sex hormones have been shown to modulate the response to T/HS and proestrous (PE) females are more resistant to T/HS-induced gut and distant organ injury, the goal of our study was to determine the contribution of estrogen receptor (ER)alpha and ERbeta in modulating the protective response of female rats to T/HS-induced gut and lung injury.The incidence of gut and lung injury was assessed in PE and ovariectomized (OVX) female rats subjected to T/HS or trauma sham shock (T/SS) as well as OVX rats that were administered estradiol (E2) or agonists for ERalpha or ERbeta immediately prior to resuscitation. Marked gut and lung injury was observed in OVX rats subjected to T/HS as compared to PE rats or E2-treated OVX rats subjected to T/HS. Both ERalpha and ERbeta agonists were equally effective in limiting T/HS-induced morphologic villous injury and bacterial translocation, whereas the ERbeta agonist was more effective than the ERalpha agonist in limiting T/HS-induced lung injury as determined by histology, Evan's blue lung permeability, bronchoalevolar fluid/plasma protein ratio and myeloperoxidase levels. Similarly, treatment with either E2 or the ERbeta agonist attenuated the induction of the intestinal iNOS response in OVX rats subjected to T/HS whereas the ERalpha agonist was only partially protective.Our study demonstrates that estrogen attenuates T/HS-induced gut and lung injury and that its protective effects are mediated by the activation of ERalpha, ERbeta or both receptors

    Development of a practicum tool to analyze the angular speed and direction of the heel's movement

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    This research aims to develop a practicum tool to analyze the angular velocity and direction of rotation produced by the wheel's movement. The study method used is research and development which is the most reliable in scientific knowledge and is concerned with changes that lead to improvements. The research and development stage begins with a discussion stage for collecting ideas, submitting designs, and making tools. The working principle of the tool was to connect the tool to the electric current. So that the wheels can rotate and observe the direction of rotation. The rotation of the wheels that touch each other is connected by a rope. The data that will be obtained from this experiment is the number of turns on the wheel, the length of time the wheel rotates, and the diameter of each wheel. Data analysis was carried out by determining the frequency, angular velocity, and direction of rotation of each wheel. The result showed the intersecting wheels had different rotational directions and angular velocities. The wheel connected to the rope has a rotating direction in the same direction at different angular velocities. Thus, the practicum tool developed can analyze the angular velocity and direction of the wheel's movement rotation

    The Impact of Emerging Safety and Effectiveness Evidence on the Use of Physician-administered Drugs: The Case of Bevacizumab for Breast Cancer

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    Spending on physician-administered drugs is high and uses not approved by the U.S. Food and Drug Administration (FDA) are frequent. While these drugs may be targets of future policy efforts to rationalize use, little is known regarding how physicians respond to emerging safety and effectiveness evidence

    How Do Payers Respond to Regulatory Actions? The Case of Bevacizumab

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    In February 2008, the US Food and Drug Administration (FDA) granted accelerated approval for bevacizumab for metastatic breast cancer. After public hearings in July 2010, and June 2011, the FDA revoked this approved indication in November 2011, on the basis of additional evidence regarding its risk/benefit profile. The Centers for Medicare and Medicaid Services, local Medicare contractors, and commercial payers varied in their stated intentions to cover bevacizumab after FDA's regulatory actions. We examined payer-specific trends in bevacizumab use after the FDA's regulatory actions

    Mapping evolutionary process: a multi-taxa approach to conservation prioritization

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    Human-induced land use changes are causing extensive habitat fragmentation. As a result, many species are not able to shift their ranges in response to climate change and will likely need to adapt in situ to changing climate conditions. Consequently, a prudent strategy to maintain the ability of populations to adapt is to focus conservation efforts on areas where levels of intraspecific variation are high. By doing so, the potential for an evolutionary response to environmental change is maximized. Here, we use modeling approaches in conjunction with environmental variables to model species distributions and patterns of genetic and morphological variation in seven Ecuadorian amphibian, bird, and mammal species. We then used reserve selection software to prioritize areas for conservation based on intraspecific variation or species-level diversity. Reserves selected using species richness and complementarity showed little overlap with those based on genetic and morphological variation. Priority areas for intraspecific variation were mainly located along the slopes of the Andes and were largely concordant among species, but were not well represented in existing reserves. Our results imply that in order to maximize representation of intraspecific variation in reserves, genetic and morphological variation should be included in conservation prioritization
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