Search results for " calcium"
showing 10 items of 342 documents
Regulation of calcium signalling by docosahexaenoic acid in human T-cells: implication of CRAC channels
2000
Abstract We elucidated the role of docosahexaenoic acid (DHA) on the increases in free intracellular calcium concentrations, [Ca2+]i, in human (Jurkat) T-cell lines. DHA evoked an increase in [Ca2+]i in a dose-dependent manner in these cells. Anti-CD3 antibody, known to stimulate increases in Ca2+ from endoplasmic reticulum (ER) via the production of inositol trisphosphate, also evoked increases in [Ca2+]i in Jurkat T-cells. We also used thapsigargin which inhibits Ca2+-ATPase of the ER and, therefore, increases Ca2+ in the cytosol. Interestingly, addition of DHA during the thapsigargin-induced peak response exerted an additive effect on the increases in [Ca2+]i in human T-cells, indicating…
Mechanisms of Synergy Between Toll-Like Receptor 4 and Triggering Receptor Expressed on Myeloid Cells-1 in Human Neutrophils
2008
Abstract The triggering receptor expressed on myeloid cells 1 (TREM-1) is an important player in the innate inflammatory response to microbial infections. Activation and expression of TREM-1 by polymorphonuclear neutrophils (PMN) occurs in concert with Toll-like receptors (TLR) such as TLR4 for bacterial lipopolysaccharide. However, it is currently unclear how this is mediated on a molecular level. Using pharmacologic inhibitors and western blot analysis we demonstrate that phosphatidyl inositide 3-kinase, phospholipase C and the mitogen activated kinase p38 are essential for the TREM-1 and TLR4 mediated respiratory burst of human PMN. The down stream phosphorylation of protein kinase B and…
[The role of the anesthesiologist in secondary hyperparathyroidism].
2010
In the last years the increasing of diabetes and hypertension has produced a considerable increase of patients with chronic renal failure; secondary hyperparathyroidism is one of the major complications. The resection of hyperfunctioning parathyroid tissue is the ultimate goal of the treatment. The preoperative examination by the anesthetist is the starting-point of the treatment. The anesthetist programs hemodialysis, the correction of fluid and electrolyte abnormalities and of the anaemia. In the operating room the anesthetist is involved in the careful monitoring of liquid infusion and anesthesiological procedure. The intraoperative parathyroid hormone (PTH) assay is an essential tool be…
Direct activation of zebrafish neurons by ultrasonic stimulation revealed by whole CNS calcium imaging
2020
Abstract Objective. Ultrasounds (US) use in neural engineering is so far mainly limited to ablation through high intensity focused ultrasound, but interesting preliminary results show that low intensity low frequency ultrasound could be used instead to modulate neural activity. However, the extent of this modulatory ability of US is still unclear, as in in vivo studies it is hard to disentangle the contribution to neural responses of direct activation of the neuron by US stimulation and indirect activation due either to sensory response to mechanical stimulation associated to US, or to propagation of activity from neighboring areas. Here, we aim to show how to separate the three effects and…
Bio-vaterite formation by glycoproteins from freshwater pearls
2010
Abstract A 48 kDa acidic and putative calcium-binding glycoprotein was isolated from pearls of the freshwater mussel Hyriopsis cumingii . This protein was compared with a related 46 kDa polypeptide, obtained from the nacreous shell of the same species. Separation by two-dimensional gel electrophoresis revealed that the difference in molecular weight is due to the higher extent of glycosylation of the 48 kDa protein existing in pearls. Evidence is presented that the sugar moieties of the protein contribute to crystal growth, starting with the nucleation step. In in vitro precipitation experiments, the 48 kDa glycoprotein of pearls directed the formation of round-shaped vaterite crystals whil…
Amorphous calcium carbonate in the shells of adult Unionoida
2011
Shells of adult individuals from two different bivalve families, Hyriopsis cumingii and Diplodon chilensis patagonicus, were studied by Micro-Raman spectroscopy and Focussed Ion Beam-assisted TEM. The shells contain amorphous calcium carbonate in a zone at the interface between the periostracum and the prismatic layer. In this area, the initial prism structures protrude from the inner periostracum layer and it is demonstrated that these structures systematically consist of highly disordered and amorphous calcium carbonate. Within this zone, ordered and disordered areas are intermingled discounting the existence of a crystallization front and favouring models of domainal crystallization proc…
Astrocytic potassium and calcium channels as integrators of the inflammatory and ischemic CNS microenvironment.
2021
Abstract Astrocytes are key regulators of their surroundings by receiving and integrating stimuli from their local microenvironment, thereby regulating glial and neuronal homeostasis. Cumulating evidence supports a plethora of heterogenic astrocyte subpopulations that differ morphologically and in their expression patterns of receptors, transporters and ion channels, as well as in their functional specialisation. Astrocytic heterogeneity is especially relevant under pathological conditions. In experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), morphologically distinct astrocytic subtypes were identified and could be linked to transcriptome changes dur…
Monitoring a Mechanochemical Reaction Reveals the Formation of a New ACC Defect Variant Containing the HCO 3 – Anion Encapsulated by an Amorphous Mat…
2020
Crystal growth & design 20(10), 6831 - 6846 (2020). doi:10.1021/acs.cgd.0c00912
Influence of aluminates phases hydration in presence of calcium sulfate on silicates phases hydration : consequences on cements optimum sulfate
2012
The mechanical properties of hydrated cements need to be optimized according to the nature of cement products. Among the factors of optimization, the addition of calcium sulphate intended to regulate the reactivity of tricalcium aluminate (C3A), in quantity and quality in cement is an essential parameter.The advancement of knowledge on the mechanisms of hydration of each cement phase allows a study devoted entirely to the concept of optimum of sulphate. We studied simple system that we complicated and we studied the evolution of hydration, porosity and mechanical properties of cement at different age. The first system studied was the mixture C3S/gypsum, the objective was to determine whethe…
Fluidity and cytosolic Ca2+ concentration of circulating polymorphonuclear leukocytes at baseline in some chronic and acute clinical conditions: revi…
2016
Abstract. Objective: In this mini-review we describe the behavior of polymorphonuclear leukocyte (PMN) membrane fluidity and of PMN cytosolic Ca2+ concentration in some chronic and acute clinical conditions. Methods: PMN membrane fluidity was evaluated employing the fluorescent probe Fura-2AM, and PMN cytosolic Ca2+ concentration was evaluated using the fluorescent probe TMA-DPH. Results: From the determination of these two parameters investigated on resting PMNs, an almost constant increase in PMN cytosolic Ca2+ concentration in chronic clinical conditions, such as vascular atherosclerotic disease with and without diabetes mellitus, essential hypertension, chronic kidney disease, and diabe…