Search results for "Bone"
showing 10 items of 2629 documents
Genetic Cell Ablation Reveals Clusters of Local Self-Renewing Microglia in the Mammalian Central Nervous System
2015
SummaryDuring early embryogenesis, microglia arise from yolk sac progenitors that populate the developing central nervous system (CNS), but how the tissue-resident macrophages are maintained throughout the organism’s lifespan still remains unclear. Here, we describe a system that allows specific, conditional ablation of microglia in adult mice. We found that the microglial compartment was reconstituted within 1 week of depletion. Microglia repopulation relied on CNS-resident cells, independent from bone-marrow-derived precursors. During repopulation, microglia formed clusters of highly proliferative cells that migrated apart once steady state was achieved. Proliferating microglia expressed …
Immune regulatory neural stem/precursor cells protect from central nervous system autoimmunity by restraining dendritic cell function.
2009
Background: The systemic injection of neural stem/precursor cells (NPCs) provides remarkable amelioration of the clinicopathological features of experimental autoimmune encephalomyelitis (EAE). This is dependent on the capacity of transplanted NPCs to engage concurrent mechanisms of action within specific microenvironments in vivo. Among a wide range of therapeutic actions alternative to cell replacement, neuroprotective and immune modulatory capacities of transplanted NPCs have been described. However, lacking is a detailed understanding of the mechanisms by which NPCs exert their therapeutic plasticity. This study was designed to identify the first candidate that exemplifies and sustains …
Skull and vertebral bone marrow are myeloid cell reservoirs for the meninges and CNS parenchyma.
2021
Getting around the blood–brain barrier The meninges comprise three membranes that surround and protect the central nervous system (CNS). Recent studies have noted the existence of myeloid cells resident there, but little is known about their ontogeny and function, and whether other meningeal immune cell populations have important roles remains unclear (see the Perspective by Nguyen and Kubes). Cugurra et al. found in mice that a large proportion of continuously replenished myeloid cells in the dura mater are not blood derived, but rather transit from cranial bone marrow through specialized channels. In models of CNS injury and neuroinflammation, the authors demonstrated that these myeloid c…
Exacerbated experimental autoimmune encephalomyelitis in mast-cell-deficient KitW-sh/W-sh mice
2011
Mast cell (MC)-deficient c-Kit mutant Kit(W/W-v) mice are protected against experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, suggesting a detrimental role for MCs in this disease. To further investigate the role of MCs in EAE, we took advantage of a recently characterized model of MC deficiency, Kit(W-sh/W-sh). Surprisingly, we observed that myelin oligodendrocyte glycoprotein (MOG)(35-55)-induced chronic EAE was exacerbated in Kit(W-sh/W-sh) compared with Kit(+/+) mice. Kit(W-sh/W-sh) mice showed more inflammatory foci in the central nervous system (CNS) and increased T-cell response against myelin. To understand whether the discrepant results obtaine…
Effect of bioglass on growth and biomineralization of SaOS-2 cells in hydrogel after 3D cell bioprinting.
2014
We investigated the effect of bioglass (bioactive glass) on growth and mineralization of bone-related SaOS-2 cells, encapsulated into a printable and biodegradable alginate/gelatine hydrogel. The hydrogel was supplemented either with polyphosphate (polyP), administered as polyP • Ca2+-complex, or silica, or as biosilica that had been enzymatically prepared from ortho-silicate by silicatein. These hydrogels, together with SaOS-2 cells, were bioprinted to computer-designed scaffolds. The results revealed that bioglass (nano)particles, with a size of 55 nm and a molar ratio of SiO2 : CaO : P2O5 of 55 : 40 : 5, did not affect the growth of the encapsulated cells. If silica, biosilica, or polyP …
Computer simulation of bottle-brush polymers with flexible backbone: good solvent versus theta solvent conditions.
2011
By Molecular Dynamics simulation of a coarse-grained bead-spring type model for a cylindrical molecular brush with a backbone chain of $N_b$ effective monomers to which with grafting density $\sigma$ side chains with $N$ effective monomers are tethered, several characteristic length scales are studied for variable solvent quality. Side chain lengths are in the range $5 \le N \le 40$, backbone chain lengths are in the range $50 \le N_b \le 200$, and we perform a comparison to results for the bond fluctuation model on the simple cubic lattice (for which much longer chains are accessible, $N_b \le 1027$, and which corresponds to an athermal, very good, solvent). We obtain linear dimensions of …
Test of multielement analysis of bone samples using instrumental neutron activation analysis (INAA) and anti-Compton spectrometry
1997
INAA and anti-Compton spectrometry has been employed in the analysis of test bone samples. Validity and accuracy of the method were checked by the use of two biological reference materials procured from the National Institute of Standards and Technology, USA (NIST) and the International Atomic Energy Agency, Austria (IAEA). NIST 1486 Bone Meal (ca. 200–800 mg) and A-11 Milk Powder (ca. 200–600 mg) samples were irradiated in the 100 kW TRIGA Mainz reactor. Concentrations of 13 elements in both biological reference materials have been determined and were found in good agreement with the certified and provisional values.
Comparison of different phosphorus-containing ligands complexing 68Ga for PET-imaging of bone metabolism
2010
Abstract 99mTc-phosphonate structures are well established tracers for bone tumour imaging. Our objective was to investigate different 68Ga-labelled phosphonate ligands concerning labelling kinetics, binding to hydroxyapatite and bone imaging using μ-PET. Seven macrocyclic phosphorus-containing ligands and EDTMP were labelled in nanomolar scale with n.c.a. 68Ga in Na-HEPES buffer at pH∼4. Except for DOTP, all ligands were labelled with >92% yield. Binding of the 68Ga-ligand complexes on hydroxyapatite was analysed to evaluate the effect of the number of the phosphorus acid groups on adsorption parameters. Adsorption of 68Ga-EDTMP and 68Ga-DOTP was >83%. For the 68Ga-NOTA-phosphonates …
Chemokine Expression Is Involved in the Vascular Neogenesis of Ewing Sarcoma: A Preliminary Analysis of the Early Stages of Angiogenesis in a Xenogra…
2018
Background Ewing sarcoma (EWS) is the second most common bone cancer in pediatric patients. Angiogenesis is a major factor for tumor growth and metastasis. Our aim was to carry out a histological, immunohistochemical, and molecular characterization of the neovascularization established between xenotransplanted tumors and the host during the initial phases of growth in nude mice in three angiogenesis experiments (ES2, ES3, and ES4). Methods The original human EWS were implanted subcutaneously on the backs of three nude mice. Tumor pieces 3 mm–4 mm in size from early passages of Nu432, Nu495, and Nu471 were also implanted subcutaneously on the backs of three sets (ES2, ES3, and ES4) of athymi…
Medical Geochemistry
2013
Preface.- How trace element contents in bronchoalveolar lavages can probe the human exposure to inhaled particulates.- Geochemistry and Biochemistry - insights into the fate and transport of Pt-based chemotherapy drugs.- Atmospheric Particulate Matter (PM) in the Middle East: Toxicity, trans-boundary transport and influence of synoptic conditions.- Reaction path modeling: theoretical aspects and applications.- An observation on the composition of urinary calculi: environment influence.- Magnetite minerals in the human brain: what's their role?.- Chemometrics and Medical Geochemistry: A brief tutorial.- Dust, metals and metalloids in the environment: from air to hair.- Metal Geochemistry of …