Search results for "Calcium"
showing 10 items of 1740 documents
Nuclear calcium signaling: An emerging topic in plants
2011
International audience; The calcium ion is probably one of the most studied second messenger both in plant and animal fields. A large number of reviews have browsed the diversity of cytosolic calcium signatures and evaluated their pleiotropic roles in plant and animal cells. In the recent years, an increasing number of reviews has focused on nuclear calcium, especially on the possible roles of nuclear calcium concentration variations on nuclear activities. Experiments initially performed on animal cells gave conflicting results that brought about a controversy about the ability of the nucleus to generate its own calcium signals and to regulate its calcium level. But in plant cells, several …
Biofortification: Effect of Iodine Fortified Food in the Healthy Population, Double-Arm Nutritional Study
2022
It is estimated that one-third of the world’s population lives in areas where iodine (I) is scarce and its deficiency is responsible for many related disorders, such as goiter, reproductive failure, hearing loss, growth impairment, congenital I deficiency syndrome, and numerous kinds of brain injury. Mineral deficiencies can be overcomeviadietary diversification and mineral supplementation. An alternative or even complementary way is represented by the intake of biofortified foods, which can tackle this lack of micronutrients. In this short-term double-arm nutritional intervention study, a cohort of ten people was supplemented with curly endive leaf biofortified with I and ten people with c…
Onset of DNA synthesis in experimentally activated ascidian eggs
1994
DNA synthesis was studied autoradiographically in unfertilized ascidian eggs (Ascidia malaca and Ciona intestinalis) that had been artificially activated by a K+-free external medium or a Ca-ionophore. Naked eggs of A. malaca were incubated in K+-free seawater that contained [3H]-thymidine for 30 min, and naked eggs of C. intestinalis were incubated in seawater supplemented with a Ca-ionophore and [3H]-thymidine for 15 min. The observations revealed limited activation in eggs treated with K+-free seawater. Activation consisted of surface modifications and the onset of DNA synthesis. Incorporation of [3H]-thymidine was detected in female nuclei of treated eggs which had not ejected their pol…
Effect of organic matrices on the determination of the trace element chemistry (Mg, Sr, Mg/Ca, Sr/Ca) of aragonitic bivalve shells (<i>Arctica …
2010
The element chemistry of biogenic carbonates can provide important data on past environments. However, the Sr/Ca and Mg/Ca ratios as well as the Mg and Sr concentrations of biological carbonates, especially aragonitic bivalves often depart from apparent thermodynamic equilibrium. When measured in situ by means of LA-ICP-MS, the Mg concentration is often substantially enriched (two- to threefold) near the organic-rich, annual growth lines. To test the hypothesis that some organic components exert a major influence on the skeletal metal content, the element chemistry of different shell components (insoluble organic matrix, IOM; dissolved CaCO3 and soluble organics, SOM) of Arctica islandica w…
Endothelial cells stimulate osteogenic differentiation of mesenchymal stem cells on calcium phosphate scaffolds
2012
The interaction of mesenchymal stem cells (MSCs) with endothelium in vivo is significant for regenerative processes in organisms. To design concepts for tissue engineering for bone regeneration based on this interaction, the osteogenic differentiation of human bone marrow-derived MSCs in a co-culture with human dermal microvascular endothelial cells (HDMECs) was studied. The experiments were focussed on the regulation of MSCs in a co-culture with HDMECs on different calcium phosphate scaffolds. Alkaline phosphatase (ALP) activity and mRNA expression of various osteogenic markers increased significantly when cells were co-cultured on materials with calcium phosphate scaffolds compared to tis…
Effect of calcium dips and chitosan coatings on postharvest life of strawberries (Fragaria x ananassa)
2006
Strawberries (Fragaria x ananassa Duch.) were treated either with 1% calcium gluconate dips, 1.5% chitosan coatings or with a coating formulation containing 1.5% chitosan + 1% calcium gluconate and stored at 20 °C for up to 4 days. The effectiveness of the treatments was assessed by evaluating their impact on the following parameters: fungal decay incidence, loss of weight, firmness, external color, pH, titratable acidity and soluble solids content. Calcium dips were effective in decreasing surface damage and delaying both fungal decay and loss of firmness compared to untreated fruit. No sign of fungal decay was observed in fruit coated with 1.5% chitosan which also reduced fruit weight los…
Novel structural insights into F-actin-binding and novel functions of calponin homology domains.
2008
Tandem calponin homology (CH) domains are well-known actin filaments (F-actin) binding motifs. There has been a continuous debate about the details of CH domain-actin interaction, mainly because atomic level structures of F-actin are not available. A recent electron microscopy study has considerably advanced our structural understanding of CH domain:F-actin complex. On the contrary, it has recently also been shown that CH domains can bind other macromolecular systems: two CH domains from separate polypeptides Ncd80, Nuf2 can form a microtubule-binding site, as well as tandem CH domains in the EB1 dimer, while the single C-terminal CH domain of alpha-parvin has been observed to bind to a alp…
Diabetes mellitus: evaluation of erythrocyte and polymorphonuclear leukocyte rheology
2015
Aim: To explore red blood cells (RBC) and leukocyte rheology, that may be relevant in the pathophysiology of diabetes mellitus. Methods and Results: Significant alterations have been observed in RBC behaviour using several filtration techniques, but the exploration of RBC deformability by laser diffractometry did not show any abnormality. We have also employed microrheological methods based on fluorescence spectroscopy: membrane microviscosity was evaluated in ghosts, while in intact RBC we explored the membrane polarity gradient using fluorescent fatty acids, the phospholipid and protein lateral mobility using respectively pyrene and pyrene-3-maleimide. Alterations emerged only using the l…
Blood Flow, Vascular Resistance and Oxygen Availability in Malignant Tumours upon Intravenous Flunarizine
1987
Tumour blood flow, an important determinant of the efficacy of presently available nonsurgical cancer treatments, significantly increased following a single I.V. injection of the calcium antagonist flunarizine. At a dose of 1 mg/kg, tumour blood flow increased approximately by 28% without a significant change in mean arterial blood pressure. The flow increase was paralleled by a similar improvement of the O2 availability to the cancer cells. The data suggest that flunarizine may provide a means of improving delivery of antineoplastic agents to tumours. Furthermore, flunarizine may also enhance the effectiveness of irradiation by increasing tumour oxygenation.
No evidence for efficacy of intrathecal verapamil in the treatment of tonic-clonic status epilepticus
1992
In two patients with refractory generalized tonic-clonic status epilepticus, 15 mg of the calcium antagonist verapamil was given by suboccipital intrathecal administration. During a 2–6-h observation period, seizure frequency did not decrease. However, in one patient, verapamil induced severe hypotension. Subsequent thiopental anesthesia suppressed convulsions immediately. Our results indicate that, in contradistinction to animal studies with different administration techniques, intrathecal administration of verapamil does not produce any anticonvulsant effect in humans.