125 research outputs found
Using airborne LiDAR intensity to predict the organic potential of waterlogged deposits
An assessment of the predictive potential of backscettered lidar intensity to identigy organic preservation of waterlogged sediments in alluvial environments
Systemic AAV vectors for widespread and targeted gene delivery in rodents
We recently developed adeno-associated virus (AAV) capsids to facilitate efficient and noninvasive gene transfer to the central and peripheral nervous systems. However, a detailed protocol for generating and systemically delivering novel AAV variants was not previously available. In this protocol, we describe how to produce and intravenously administer AAVs to adult mice to specifically label and/or genetically manipulate cells in the nervous system and organs, including the heart. The procedure comprises three separate stages: AAV production, intravenous delivery, and evaluation of transgene expression. The protocol spans 8 d, excluding the time required to assess gene expression, and can be readily adopted by researchers with basic molecular biology, cell culture, and animal work experience. We provide guidelines for experimental design and choice of the capsid, cargo, and viral dose appropriate for the experimental aims. The procedures outlined here are adaptable to diverse biomedical applications, from anatomical and functional mapping to gene expression, silencing, and editing
Damping behavior of 3D woven metallic lattice materials
Cu and NiCr metallic lattice materials of two different micro-architectures were manufactured with a 3D weaving process. Dynamic mechanical analysis experiments demonstrated that the damping properties of these materials are much greater than their bulk counterparts and were found to have damping loss coefficients comparable to polymers, but with much higher maximum use temperatures. The magnitude of the damping phenomenon is characterized experimentally, and the importance of Coulomb (frictional) damping and inertial damping are investigated using a finite element mode
Systemic AAV vectors for widespread and targeted gene delivery in rodents
We recently developed adeno-associated virus (AAV) capsids to facilitate efficient and noninvasive gene transfer to the central and peripheral nervous systems. However, a detailed protocol for generating and systemically delivering novel AAV variants was not previously available. In this protocol, we describe how to produce and intravenously administer AAVs to adult mice to specifically label and/or genetically manipulate cells in the nervous system and organs, including the heart. The procedure comprises three separate stages: AAV production, intravenous delivery, and evaluation of transgene expression. The protocol spans 8 d, excluding the time required to assess gene expression, and can be readily adopted by researchers with basic molecular biology, cell culture, and animal work experience. We provide guidelines for experimental design and choice of the capsid, cargo, and viral dose appropriate for the experimental aims. The procedures outlined here are adaptable to diverse biomedical applications, from anatomical and functional mapping to gene expression, silencing, and editing
Engineering the Melanocortin-4 Receptor to Control Constitutive and Ligand-Mediated Gs Signaling In Vivo
The molecular and functional diversity of G protein–coupled receptors is essential to many physiological processes. However, this diversity presents a significant challenge to understanding the G protein–mediated signaling events that underlie a specific physiological response. To increase our understanding of these processes, we sought to gain control of the timing and specificity of Gs signaling in vivo. We used naturally occurring human mutations to develop two Gs-coupled engineered receptors that respond solely to a synthetic ligand (RASSLs). Our Gs-coupled RASSLs are based on the melanocortin-4 receptor, a centrally expressed receptor that plays an important role in the regulation of body weight. These RASSLs are not activated by the endogenous hormone α-melanocyte-stimulating hormone but respond potently to a selective synthetic ligand, tetrahydroisoquinoline. The RASSL variants reported here differ in their intrinsic basal activities, allowing the separation of the effects of basal signaling from ligand-mediated activation of the Gs pathway in vivo. These RASSLs can be used to activate Gs signaling in any tissue, but would be particularly useful for analyzing downstream events that mediate body weight regulation in mice. Our study also demonstrates the use of human genetic variation for protein engineering
Intermittent preventive treatment for the prevention of malaria during pregnancy in high transmission areas
Malaria in pregnancy is one of the major causes of maternal morbidity and adverse birth outcomes. In high transmission areas, its prevention has recently changed, moving from a weekly or bimonthly chemoprophylaxis to intermittent preventive treatment (IPTp). IPTp consists in the administration of a single curative dose of an efficacious anti-malarial drug at least twice during pregnancy – regardless of whether the woman is infected or not. The drug is administered under supervision during antenatal care visits. Sulphadoxine-pyrimethamine (SP) is the drug currently recommended by the WHO. While SP-IPTp seems an adequate strategy, there are many issues still to be explored to optimize it. This paper reviewed data on IPTp efficacy and discussed how to improve it. In particular, the determination of both the optimal number of doses and time of administration of the drug is essential, and this has not yet been done. As both foetal growth and deleterious effects of malaria are maximum in late pregnancy women should particularly be protected during this period. Monitoring of IPTp efficacy should be applied to all women, and not only to primi- and secondigravidae, as it has not been definitively established that multigravidae are not at risk for malaria morbidity and mortality. In HIV-positive women, there is an urgent need for specific information on drug administration patterns (need for higher doses, possible interference with sulpha-based prophylaxis of opportunistic infections). Because of the growing level of resistance of parasites to SP, alternative drugs for IPTp are urgently needed. Mefloquine is presently one of the most attractive options because of its long half life, high efficacy in sub-Saharan Africa and safety during pregnancy. Also, efforts should be made to increase IPTp coverage by improving the practices of health care workers, the motivation of women and their perception of malaria complications in pregnancy. Because IPTp is not applicable in early pregnancy, which is a period when malaria may also be deleterious for women and their offspring, there is a necessity to integrate this strategy with other preventive measures which can be applied earlier in pregnancy such as insecticide-treated nets
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference
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