ABSTRACT
BACKGROUND: In vivo angiogenesis is normal and vital process in growth and development, wound healing, and formation of granulation tissue wherein new blood vessels form from preexisting vessels as part of revascularization. Platelet-rich products promote wound healing associated with angiogenesis. Biomaterials such as titanium were found to be angiogenic. Unlike in vivo situations, in vitro angiogenesis, study cells, within a controlled environment. AIMS: The aim of this study is to evaluate the angiogenic potential of a novel platelet-rich product. MATERIALS AND METHODS: Blood was drawn from volunteers with informed consent. Blood samples were centrifuged to obtain platelet-rich products. Platelet concentrates prepared were platelet-rich plasma (PRP), platelet-rich fibrin, and a novel platelet-rich product which is titanium-prepared PRP (TPRP), obtained using titanium. The study which compared platelet concentrate was divided into four groups subjected to tissue culture. Phase-contrast microscope was used to determine the rate of growth by cell counting. STATISTICAL ANALYSIS: ANOVA was used for comparison within groups and post hoc for multiple comparisons. RESULTS: TPRP group showed granular ground substance. Group with platelet-rich fibrin (PRF) shows a high rate of growth whereas those with TPRP showed better growth rate when compared to its counterpart, PRP. CONCLUSIONS: This is the first study which introduces TPRP. Previous studies have proved that titanium-prepared PRF has better structural quality than its counterpart platelet-rich fibrin. This study concludes that TPRP has better angiogenic potential than its counterpart PRP. Further in vivo studies are needed to promote TPRP as a new generation of platelet products.
ABSTRACT
In the CNS, an antagonistic interaction has been shown between adenosine A(2A) and dopamine D(2) receptors (A(2A)Rs and D(2)Rs) that may be relevant both in normal and pathological conditions (i.e., Parkinson's disease). Thus, the molecular determinants mediating this receptor-receptor interaction have recently been explored, as the fine tuning of this target (namely the A(2A)R/D(2)R oligomer) could possibly improve the treatment of certain CNS diseases. Here, we used a fluorescence resonance energy transfer-based approach to examine the allosteric modulation of the D(2)R within the A(2A)R/D(2)R oligomer and the dependence of this receptor-receptor interaction on two regions rich in positive charges on intracellular loop 3 of the D(2)R. Interestingly, we observed a negative allosteric effect of the D(2)R agonist quinpirole on A(2A)R ligand binding and activation. However, these allosteric effects were abolished upon mutation of specific arginine residues (217-222 and 267-269) on intracellular loop 3 of the D(2)R, thus demonstrating a major role of these positively charged residues in mediating the observed receptor-receptor interaction. Overall, these results provide structural insights to better understand the functioning of the A(2A)R/D(2)R oligomer in living cells.
Subject(s)
Receptor, Adenosine A2A/chemistry , Receptor, Adenosine A2A/genetics , Receptors, Dopamine D2/chemistry , Receptors, Dopamine D2/physiology , Adenosine A2 Receptor Agonists/pharmacology , Adenosine A2 Receptor Antagonists/pharmacology , Allosteric Regulation/drug effects , Allosteric Regulation/genetics , Arginine/genetics , Dopamine Agonists/pharmacology , HEK293 Cells , Humans , Intracellular Fluid/chemistry , Intracellular Fluid/drug effects , Intracellular Fluid/physiology , Mutagenesis, Site-Directed , Protein Binding/drug effects , Protein Binding/genetics , Protein Structure, Tertiary/genetics , Quinpirole/pharmacology , Receptor, Adenosine A2A/metabolism , Receptors, Dopamine D2/geneticsABSTRACT
Electron beam wire tomography in the H-1NF heliac enables high resolution mapping of vacuum flux surfaces with minimal disruption of the plasma operations schedule. Recent experimental results have proven this technique to be a highly accurate and high resolution method for mapping vacuum magnetic islands. Islands of width as small as delta approximately 8 mm have been measured, providing estimates of the internal rotational transform of the island. Point-to-point comparison of the mapping results with computer tracing, in conjunction with an image warping technique, enables systematic exploration of magnetic islands and surfaces of interest. Recent development of a fast mapping technique significantly reduced the mapping time and made this technique suitable for mapping at higher magnetic fields. This article presents recent experimental results and associated techniques.
