ABSTRACT:The objective of the study was to establish primary cultured porcine brain microvessel endothelial cells (PBMECs) as an in vitro model to predict the blood-brain barrier (BBB) permeability in vivo. The intercellular tight junction formation of PBMECs was examined by electron microscopy and measured by transendothelial electrical resistance (TEER). The mRNA expression of several BBB transporters in PBMECs was determined by reverse transcriptionpolymerase chain reaction analysis. The in vitro permeability of 16 structurally diverse compounds, representing a range of passive diffusion and transporter-mediated mechanisms of brain penetration, was determined in PBMECs. Except for the perfusion flow rate marker diazepam, the BBB permeability of these compounds was determined either in our laboratory or as reported in literature using in situ brain perfusion technique in rats. Results in the present study showed that PBMECs had a high endothelium homogeneity, an mRNA expression of several BBB transporters, and high TEER values. Culturing with rat astrocyte-conditioned medium increased the TEER of PBMECs, but had no effect on the permeability of sucrose, a paracellular diffusion marker. The PB-MEC permeability of lipophilic compounds measured under stirred conditions was greatly increased compared with that measured under unstirred conditions. The PBMEC permeability of the 15 test compounds, determined under the optimized study conditions, correlated with the in situ BBB permeability with an r 2 of 0.60.Removal of the three system L substrates increased the r 2 to 0.89.In conclusion, the present PBMEC model may be used to predict or rank the in vivo BBB permeability of new chemical entities in a drug discovery setting.One major hurdle of successful central nervous system drug delivery is to penetrate the blood-brain barrier (BBB) to reach the therapeutic targets. The BBB is a continuous layer of endothelial cells that are connected to each other through tight junctions. In contrast to the endothelial cells of peripheral blood vessels, the brain microvessel endothelial cells are characterized by unique intercellular tight junctions, the absence of fenestrations, and minimal pinocytic activity. The BBB represents a physiological barrier that efficiently restricts free paracellular passage of most substances from the blood to the brain extracellular environment. Furthermore, the brain microvessel endothelial cells possess a variety of metabolic enzyme systems, which further limit the brain entry of compounds (Pardridge, 1983). Finally, a complex of membrane-bound transport systems, including active efflux transporters, such as P-glycoprotein (Pgp) (Schinkel et al., 1996;Miller et al., 2000) and multidrug resistanceassociated protein (MRP) Zhang et al., 2000), and active uptake transporters, such as the system L amino acid transporter (LAT) (Pardridge, 1983;Smith, 1991), further regulates brain penetration.Pharmaceutical companies have been actively pursuing various methods to accurately predict the brain penetrati...

This is EDIS document HR 020, a publication of the Department of Food and Resource Economics, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL. Published July 2002. https://edis.ifas.ufl.edu/hr020

Issues related to searchability and ease of access have plagued fan fiction since its inception. This paper discusses the predominate forms of fan-mediated indexing and descriptive metadata, commonly referred to as folksonomy or tagging, and compares the benefits and disadvantages of each model. These models fall into three broad categories: free tagging, controlled vocabulary, and hybrid folksonomy. Each model has distinct advantages and shortcomings related to findability, results filtering, and creative empowerment. Examples for each are provided. Possible ramifications to fan fiction from improved metadata and access are also discussed.

In healthy arteries, blood flow is regulated by microvascular tone assessed by changes in blood flow volume and vascular resistance to endothelium-dependent and -independent vasodilators. We developed a novel method of using intravascular ultrasound (IVUS) and a Doppler flow wire to measure changes in blood flow volume and vascular resistance of the profunda arterial bed. We assessed the variability over 6 months in measuring microvascular endothelium-dependent dilation to acetylcholine and endothelium-independent dilation to adenosine in 20 subjects who were part of a larger study of Gulf War Illness without obstructive peripheral artery disease. Vasomotor function was assessed by Infusions of control (dextrose), acetylcholine (10-6M), adenosine (50μg), and nitroglycerin (25μg/ml). 400 IVUS and 240 flow velocity images were measured a mean 6 (SD = 2) months apart blind to measurement and infusion stage. The mean (SD) baseline profunda flow was 227 (172) ml/min and vascular resistance 4.6 x 104 (2.4 x 104) dynes-s/cm5. The intraclass correlation coefficients for 6-month variability for vascular function were excellent (range 0.827–0.995). Bland-Altman analyses showed mean differences of less than 2% for microvascular endothelium-dependent function (flow volume and resistance) and less than 1% for macrovascular endothelium-dependent function with acceptable limits of agreement. In 49 subjects assessing concurrent validity of the technique against atherosclerosis risk factors, we observed greater impairment in microvascular endothelium-dependent function per year of age (flow volume = -1.4% (p = 0.018), vascular resistance = 1.5% (p = 0.015)) and current smoking (flow volume = -36.7% (p = .006), vascular resistance = 50.0% (p<0.001)). This novel method of assessing microvascular vasomotor function had acceptable measurement reproducibility and validity.

Green market mechanisms, as part of the architecture of climate finance, have become key components of international environmental frameworks. One of the most widely known mechanisms for climate change mitigation has been the creation of Reducing Emissions from Deforestation and Forest Degradation (REDD+). The purpose of this paper is to trace global discourses and narratives throughout REDD+ official documents and compare them to the implementation on the ground to determine the extent that REDD+ meets its stated objectives in the Ghanaian context. Then, given the gaps in discourse and practice, this paper aims to define the inexplicit consequences, or rather instrumental effects, of REDD+. Discourse analysis of official REDD+ documents and land policies combined with qualitative interviews and focus groups to determine the linkages between discourse and practice of REDD+ and the impacts of these gaps. While critical civic environmentalism, highlighting environmental justice as a core principle, was somewhat incorporated into official discourse from the international to the national level, the depoliticization of the discourse and the apolitical nature of interventions make these justice concerns negligible and create gaps in discourse and practice. These gaps create disjointed, infeasible policies that establish REDD+ as a fad to bring in financial resources that expand state control of forest resources under the veil of social-ecological responsibility. As a result, state power expands into rural areas, allowing for greater control over land and forests at the expense of local communities.