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7,941 result(s) for "Calcium content"
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Harnessing global fisheries to tackle micronutrient deficiencies
Micronutrient deficiencies account for an estimated one million premature deaths annually, and for some nations can reduce gross domestic product 1 , 2 by up to 11%, highlighting the need for food policies that focus on improving nutrition rather than simply increasing the volume of food produced 3 . People gain nutrients from a varied diet, although fish—which are a rich source of bioavailable micronutrients that are essential to human health 4 —are often overlooked. A lack of understanding of the nutrient composition of most fish 5 and how nutrient yields vary among fisheries has hindered the policy shifts that are needed to effectively harness the potential of fisheries for food and nutrition security 6 . Here, using the concentration of 7 nutrients in more than 350 species of marine fish, we estimate how environmental and ecological traits predict nutrient content of marine finfish species. We use this predictive model to quantify the global spatial patterns of the concentrations of nutrients in marine fisheries and compare nutrient yields to the prevalence of micronutrient deficiencies in human populations. We find that species from tropical thermal regimes contain higher concentrations of calcium, iron and zinc; smaller species contain higher concentrations of calcium, iron and omega-3 fatty acids; and species from cold thermal regimes or those with a pelagic feeding pathway contain higher concentrations of omega-3 fatty acids. There is no relationship between nutrient concentrations and total fishery yield, highlighting that the nutrient quality of a fishery is determined by the species composition. For a number of countries in which nutrient intakes are inadequate, nutrients available in marine finfish catches exceed the dietary requirements for populations that live within 100 km of the coast, and a fraction of current landings could be particularly impactful for children under 5 years of age. Our analyses suggest that fish-based food strategies have the potential to substantially contribute to global food and nutrition security. Nutrient content analyses of marine finfish and current fisheries landings show that fish have the potential to substantially contribute to global food and nutrition security by alleviating micronutrient deficiencies in regions where they are prevalent.
Terahertz Irradiation Promotes Angiogenesis in vitro by Enhancing Permeability of the Voltage-Gated Calcium Channel
Terahertz (THz) waves, positioned between microwave and infrared in the electromagnetic spectrum, have promising applications in medical imaging and biomedicine. In this study, terahertz irradiation at 2.52 THz (100 mW/cm 2 ) did not alter the proliferation of human umbilical vein endothelial cells (HUVECs), but significantly enhanced their angiogenic capacity. This enhancement was accompanied by increased levels of angiogenesis-related proteins such as VEGF in the culture supernatant. ATAC sequencing and RNA sequencing revealed a significant increase in the expression of cytoskeleton-associated genes, including PDXP and SH3BP1, post-irradiation. Additionally, intracellular calcium concentration, closely linked to angiogenesis, markedly increased following terahertz exposure. However, diltiazem significantly mitigated the enhanced angiogenic capacity induced by terahertz irradiation. In conclusion, terahertz irradiation promotes angiogenesis in HUVECs, partly by activating the VEGF signaling pathway through increased calcium fluxes.
Characterization of intracellular calcium mobilization induced by remimazolam, a newly approved intravenous anesthetic
Many anesthetics, including Propofol, have been reported to induce elevation of intracellular calcium, and we were interested to investigate the possible contribution of calcium elevation to the mechanism of the newly approved remimazolam actions. Remimazolam is an intravenous anesthetic first approved in Japan in July 2020, and is thought to exert its anesthetic actions via γ-aminobutyric acid A (GABA A ) receptors; however, the precise mechanisms of how remimazolam elevates intracellular calcium levels remains unclear. We examined the remimazolam-induced elevation of intracellular calcium using SHSY-5Y neuroblastoma cells, COS-7 cells, HEK293 cells, HeLa cells, and human umbilical vein endothelial cells (HUVECs) loaded with fluorescent dyes for live imaging. We confirmed that high concentrations of remimazolam (greater than 300 μM) elevated intracellular calcium in a dose-dependent manner in these cells tested. This phenomenon was not influenced by elimination of extracellular calcium. The calcium elevation was abolished when intracellular or intraendoplasmic reticulum (ER) calcium was depleted by BAPTA-AM or thapsigargin, respectively, suggesting that calcium was mobilized from the ER. Inhibitors of G-protein coupled receptors (GPCRs)-mediated signals, including U-73122, a phospholipase C (PLC) inhibitor and xestospongin C, an inositol 1,4,5-triphosphate receptors (IP 3 R) antagonist, significantly suppressed remimazolam-induced calcium elevation, whereas dantrolene, a ryanodine receptor antagonist, did not influence remimazolam-induced calcium elevation. Meanwhile, live imaging of ER during remimazolam stimulation using ER-tracker showed no morphological changes. These results suggest that high doses of remimazolam increased intracellular calcium concentration in a dose-dependent manner in each cell tested, which was predicted to be caused by calcium mobilization from the ER. In addition, our studies using various inhibitors revealed that this calcium elevation might be mediated by the GPCRs-IP 3 pathway. However, further studies are required to identify which type of GPCRs is involved.
Biocementation of calcareous sand using soluble calcium derived from calcareous sand
A soil improvement method based on a microbially induced carbonate precipitation (MICP) process has been developed in recent years. In this method, calcium carbonate is precipitated in-situ to act as a cementing agency. Calcium chloride is normally used as the calcium source for the MICP process. The use of calcium chloride causes two problems. The first is chloride is corrosive to concrete, and the second is the cost of calcium chloride is relatively high. An improvement to this method is to use other alternative calcium sources. A method to produce soluble calcium using calcium rich calcareous sand and use it as a calcium source for the MICP process to improve the properties of soil has been proposed in this paper. A comparative study between the effect of MICP treatment using soluble calcium produced from calcareous sand and that using calcium chloride with the same concentration of calcium was carried out. The results from both series of tests showed that with increasing amounts of cementation solutions, the strength and stiffness of the treated calcareous sand increased and the permeability decreased. The scanning electron microscopy (SEM) and X-ray diffraction analyses revealed that the aragonite crystals with an acicular mineral morphology were formed when the soluble calcium was used, whereas the calcite crystals with a rhombohedral mineral morphology were formed when calcium chloride was used. This study also shows that it is feasible to treat calcareous sand using a MICP method with soluble calcium produced from calcareous sand.
Electromechanical vortex filaments during cardiac fibrillation
Using optical mapping and 3D ultrasound, the dynamics and interactions between electrical and mechanical phase singularities were analysed by simultaneously measuring the membrane potential, intracellular calcium concentration and mechanical contractions of the heart during normal rhythm and fibrillation. Vortices cause a dangerous stir in the heart Cardiac ventricular fibrillation is a life-threatening disturbance in heart rhythm and function. It is thought to be triggered by abnormal patterns of electrical activity forming mechanical vortices within the heart muscle. This activity has never been visualized, only inferred from electrical vortices observed on the surface of the heart. Jan Christoph and colleagues combine high-resolution four-dimensional ultrasound imaging with optical mapping to visualize three-dimensional mechanical waves of contracting and dilating tissue propagating throughout the ventricular muscle during regular rhythm in perfused pig hearts. Upon the induction of ventricular fibrillation, electrical and mechanical scroll waves form within the ventricular wall. The findings confirm the prediction made 30 years ago that three-dimensional vortex-like waves inside the heart drive cardiac arrhythmias. The self-organized dynamics of vortex-like rotating waves, which are also known as scroll waves, are the basis of the formation of complex spatiotemporal patterns in many excitable chemical and biological systems 1 , 2 , 3 , 4 . In the heart, filament-like phase singularities 5 , 6 that are associated with three-dimensional scroll waves 7 are considered to be the organizing centres of life-threatening cardiac arrhythmias 7 , 8 , 9 , 10 , 11 , 12 , 13 . The mechanisms that underlie the onset, maintenance and control 14 , 15 , 16 of electromechanical turbulence in the heart are inherently three-dimensional phenomena. However, it has not previously been possible to visualize the three-dimensional spatiotemporal dynamics of scroll waves inside cardiac tissues. Here we show that three-dimensional mechanical scroll waves and filament-like phase singularities can be observed deep inside the contracting heart wall using high-resolution four-dimensional ultrasound-based strain imaging. We found that mechanical phase singularities co-exist with electrical phase singularities during cardiac fibrillation. We investigated the dynamics of electrical and mechanical phase singularities by simultaneously measuring the membrane potential, intracellular calcium concentration and mechanical contractions of the heart. We show that cardiac fibrillation can be characterized using the three-dimensional spatiotemporal dynamics of mechanical phase singularities, which arise inside the fibrillating contracting ventricular wall. We demonstrate that electrical and mechanical phase singularities show complex interactions and we characterize their dynamics in terms of trajectories, topological charge and lifetime. We anticipate that our findings will provide novel perspectives for non-invasive diagnostic imaging and therapeutic applications.
Protective Effects of SKF-96365, a Non-Specific Inhibitor of SOCE, against MPP+-Induced Cytotoxicity in PC12 Cells: Potential Role of Homer1
Parkinson's disease (PD) is the most common neurodegenerative movement disorder, characterized by loss of dopominergic (DA) neurons in substantia nigra pars compacta (SNpc), and can be experimentally mimicked by the neurotoxin MPP(+) in vitro models. In this study, we investigated the potential protective effect of SKF-96365, a non-specific inhibitor of SOCE (store-operated calcium entry), on MPP(+) induced cytotoxicity in PC12 cells. We found that pretreatment with SKF-96365 (10 µM and 50 µM) 30 min before injury significantly increased cell viability, decreased LDH release, prevented nuclear damage, and inhibited apoptotic cell death in MPP(+) stressed PC12 cells. The results of calcium image using the ratiometric calcium indicator Fura-2-AM also showed that SKF-96365 reduced the intracellular calcium overload induced by MPP(+) in PC12 cells. In addition, SKF-96365 decreased the expression of Homer1, a more recently discovered postsynaptic scaffolding protein with calcium modulating function, following MPP(+) administration in PC12 cells, while had no statistically significant effects on endoplasmic reticulum (ER) calcium concentration. Furthermore, overexpression of Homer1 by using recombinant lentivirus partly reversed protective effects of SKF-96365 against MPP(+) injury. The ER Ca(2+) release was further amplified and ER calcium recovery was delayed by Homer1 upregulation in PC12 cells following MPP(+) insult. Taken together, these data suggest that SKF-96365 protects PC12 cells against MPP(+) induced cytotoxicity, and this protection may be at least in part on the inhibition of intracellular calcium overload and suppression of Homer1-mediated ER Ca(2+) release.
Determining the effect of different cooking methods on the nutritional composition of salmon (Salmo salar) and chilean jack mackerel (Trachurus murphyi) fillets
The effect of four cooking methods was evaluated for proximate composition, fatty acid, calcium, iron, and zinc content in salmon and Chilean jack mackerel. The moisture content of steamed salmon decreased (64.94%) compared to the control (68.05%); a significant decrease was observed in Chilean jack mackerel in all the treatments when compared to the control (75.37%). Protein content in both salmon and Chilean jack mackerel significantly increased under the different treatments while the most significant decrease in lipids was found in oven cooking and canning for salmon and microwaving for Chilean jack mackerel. Ash concentration in both salmon and Chilean jack mackerel did not reveal any significant differences. Iron and calcium content only had significant changes in steaming while zinc did not undergo any significant changes in the different treatments. Finally, no drastic changes were observed in the fatty acid profile in both salmon and Chilean jack mackerel.
A 3D diffusional-compartmental model of the calcium dynamics in cytosol, sarcoplasmic reticulum and mitochondria of murine skeletal muscle fibers
Variations of free calcium concentration ([Ca2+]) are powerful intracellular signals, controlling contraction as well as metabolism in muscle cells. To fully understand the role of calcium redistribution upon excitation and contraction in skeletal muscle cells, the local [Ca2+] in different compartments needs to be taken into consideration. Fluorescent probes allow the determination of [Ca2+] in the cytosol where myofibrils are embedded, the lumen of the sarcoplasmic reticulum (SR) and the mitochondrial matrix. Previously, models have been developed describing intracellular calcium handling in skeletal and cardiac muscle cells. However, a comprehensive model describing the kinetics of the changes in free calcium concentration in these three compartments is lacking. We designed a new 3D compartmental model of the half sarcomere with radial symmetry, which accounts for diffusion of Ca2+ into the three compartments and simulates its dynamics at rest and at various rates of stimulation in mice skeletal muscle fibers. This model satisfactorily reproduces both the amplitude and time course of the variations of [Ca2+] in the three compartments in mouse fast fibers. As an illustration of the applicability of the model, we investigated the effects of Calsequestrin (CSQ) ablation. CSQ is the main Ca2+ buffer in the SR, localized in close proximity of its calcium release sites and near to the mitochondria. CSQ knock-out mice muscles still preserve a near-normal contractile behavior, but it is unclear whether this is caused by additional SR calcium buffering or a significant contribution of calcium entry from extracellular space, via stored-operated calcium entry (SOCE). The model enabled quantitative assessment of these two scenarios by comparison to measurements of local calcium in the cytosol, the SR and the mitochondria. In conclusion, the model represents a useful tool to investigate the impact of protein ablation and of pharmacological interventions on intracellular calcium dynamics in mice skeletal muscle.
Size-resolved aerosol pH over Europe during summer
The dependence of aerosol acidity on particle size, location, and altitude over Europe during a summertime period is investigated using the hybrid version of aerosol dynamics in the chemical transport model PMCAMx. The pH changes more with particle size in northern and southern Europe owing to the enhanced presence of non-volatile cations (Na, Ca, K, Mg) in the larger particles. Differences of up to 1–4 pH units are predicted between sub- and supermicron particles, while the average pH of PM1−2.5 can be as much as 1 unit higher than that of PM1. Most aerosol water over continental Europe is associated with PM1, while coarse particles dominate the water content in the marine and coastal areas due to the relatively higher levels of hygroscopic sea salt. Particles of all sizes become increasingly acidic with altitude (0.5–2.5 units pH decrease over 2.5 km) primarily because of the decrease in aerosol liquid water content (driven by humidity changes) with height. Inorganic nitrate is strongly affected by aerosol pH with the highest average nitrate levels predicted for the PM1−5 range and over locations where the pH exceeds 3. Dust tends to increase aerosol pH for all particle sizes and nitrate concentrations for supermicron range particles. This effect of dust is quite sensitive to its calcium content. The size-dependent pH differences carry important implications for pH-sensitive processes in the aerosol.
Calcium Electroporation: Evidence for Differential Effects in Normal and Malignant Cell Lines, Evaluated in a 3D Spheroid Model
Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill efficacy-and normal cell sensitivity. Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p<0.0001) or electrochemotherapy using bleomycin (p<0.0001). Strikingly, the size of normal fibroblast spheroids was neither affected after calcium electroporation nor electrochemotherapy using bleomycin, indicating that calcium electroporation, like electrochemotherapy, will have limited adverse effects on the surrounding normal tissue when treating with calcium electroporation. The intracellular ATP level, which has previously been shown to be depleted after calcium electroporation, was measured in the spheroids after treatment. The results showed a dramatic decrease in the intracellular ATP level (p<0.01) in all four spheroid types-malignant as well as normal. In conclusion, calcium electroporation seems to be more effective in inducing cell death in cancer cell spheroids than in a normal fibroblast spheroid, even though intracellular ATP level is depleted in all spheroid types after treatment. These results may indicate an important therapeutic window for this therapy; although further studies are needed in vivo and in patients to investigate the effect of calcium electroporation on surrounding normal tissue when treating tumors.