Effects of anti-CD4 antibody treatment on calcium ions influx in peanut-sensitized C3H/HeJ mice

The precise mechanism underlying the effects of anti-CD4 antibody and calcium ions(Ca^(2+)) in peanut allergy remains unknown.C3 H/HeJ mice sensitized with peanut protein extract(PPE)were injected with anti-CD4 antibodies for 4 weeks.Stimulation with PPE increased the specific immunoglobulin E(IgE),cytokine,histamine,and mMcp-1 levels,upregulated decorin(Dcn)expression,induced Ca^(2+) inflow in the spleen,and augmented the expression of the transcription factors GATA-3 and Foxp3,which resulted in Th2 and Treg cell activation.Notably,the Ca^(2+) levels were positively correlated with the histamine,interleukin(IL)-4,IL-5,and IL-13 levels,and negatively correlated with IL-10 levels.However,administration of anti-CD4 antibodies markedly alleviated allergic symptoms,activated T cells,and reduced Ca^(2+) inflow,cytokine,histamine,mMcp-1,and the IgHG3,CXCLI2,MMP2 and FABP4 gene.Our results indicated that anti-CD4 antibodies can ameliorate PPE-induced allergy,which is probably related to the suppression of Ca^(2+) inflow,and inhibiting histamine,cytokine and IgHG3,CXCL12,MMP2,and FABP4,thus exerting a protective effect against PPEsensitized food allergy.

Elevated extracellular calcium ions accelerate the proliferation and migration of HepG2 cells and decrease cisplatin sensitivity

Hepatoblastoma is the most frequent liver malignancy in children.HepG2 has been discovered as a hepatoblastoma-derived cell line and tends to form clumps in culture.Intriguingly,we observed that the addition of calcium ions reduced cell clumping and disassociated HepG2 cells.The calcium signal is in connection with a series of processes critical in the tumorigenesis.Here,we demonstrated that extracellular calcium ions induced morphological changes and enhanced the epithelial-mesenchymal transition in HepG2 cells.Mechanistically,calcium ions promoted HepG2 proliferation and migration by up-regulating the phosphorylation levels of focal adhesion kinase(FAK),protein kinase B,and p38 mitogen-activated protein kinase.The inhibitor of FAK or Ca2+/calmodulin-dependent kinaseⅡ(CaMKⅡ)reversed the Ca2+-induced effects on HepG2 cells,including cell proliferation and migration,epithelial-mesenchymal transition protein expression levels,and phosphorylation levels of FAK and protein kinase B.Moreover,calcium ions decreased HepG2 cells'sensitivity to cisplatin.Furthermore,we found that the expression levels of FAK and CaMKⅡwere increased in hepatoblastoma.The group with high expression levels of FAK and CaMKⅡexhibited significantly lower ImmunoScore as well as CD8+T and NK cells.The expression of CaMKⅡwas positively correlated with that of PDCD1 and LAG3.Correspondingly,the expression of FAK was negatively correlated with that of TNFSF9,TNFRSF4,and TNFRSF18.Collectively,extracellular calcium accelerates HepG2 cell proliferation and migration via FAK and CaMKⅡand enhances cisplatin resistance.FAK and CaMKⅡshape immune cell infiltration and responses in tumor microenvironments,thereby serving as potential targets for hepatoblastoma.

Effects of clay and calcium ions on coal flotation

The microflotation of three single minerals,mixed coal–kaolinite and mixed coal–montmorillonite were examined to study the effects of clay and calcium ions on coal flotation.The results show that the ash content of flotation concentrate increases by 3%in the presence of clay minerals,and the ash content would further increase by 3%in co-presence of clay minerals and high concentration of Ca2+.Scanning electron microscope(SEM)images and elemental spectrum analysis indicate that fne clay particles that coat on the coal surface,which is called slime coating,can affect the coal flotation.The slime coating would be induced much more easily in the presence of Ca2+.

Bio-cementation for tidal erosion resistance improvement of foreshore slopes based on microbially induced magnesium and calcium precipitation

In most coastal and estuarine areas,tides easily cause surface erosion and even slope failure,resulting in severe land losses,deterioration of coastal infrastructure,and increased floods.The bio-cementation technique has been previously demonstrated to effectively improve the erosion resistance of slopes.Seawater contains magnesium ions(Mg^(2+))with a higher concentration than calcium ions(Ca^(2+));therefore,Mg^(2+)and Ca^(2+)were used together for bio-cementation in this study at various Mg^(2+)/Ca^(2+)ratios as the microbially induced magnesium and calcium precipitation(MIMCP)treatment.Slope angles,surface strengths,precipitation contents,major phases,and microscopic characteristics of precipitation were used to evaluate the treatment effects.Results showed that the MIMCP treatment markedly enhanced the erosion resistance of slopes.Decreased Mg^(2+)/Ca^(2+)ratios resulted in a smaller change in angles and fewer soil losses,especially the Mg^(2+)concentration below 0.2 M.The decreased Mg^(2+)/Ca^(2+)ratio achieved increased precipitation contents,which contributed to better erosion resistance and higher surface strengths.Additionally,the production of aragonite would benefit from elevated Mg^(2+)concentrations and a higher Ca^(2+)concentration led to more nesquehonite in magnesium precipitation crystals.The slopes with an initial angle of 53°had worse erosion resistance than the slopes with an initial angle of 35°,but the Mg^(2+)/Ca^(2+)ratios of 0.2:0.8,0.1:0.9,and 0:1.0 were effective for both slope stabilization and erosion mitigation to a great extent.The results are of great significance for the application of MIMCP to improve erosion resistance of foreshore slopes and the MIMCP technique has promising application potential in marine engineering.

Effect of calcium ions on the secondary structures of photosystemⅡ and its relations with photoinhibition

Calcium ions play an important role in the oxygen_evolving process of photosystem Ⅱ as demonstrated in many experiments. The changes of the secondary structures of PS Ⅱ induced by the depletion of Ca 2+ were reported. The results indicated that the removal of Ca 2+ led to the transition of α helix to turns and sheet structures. While Ca 2+ was re_added to the media, only the structures changed to turns could be recovered. The protein conformational changes of PS Ⅱ during the donor side photoinhibition induced by the depletion of Ca 2+ were also studied. This showed that the protein conformational changes differed between the control and Ca 2+ _depleted samples in a short period of illumination (within 10 min). However, the changes became similar when the illumination time was increased.

Physicochemical properties and release characteristics of calcium alginate microspheres loaded with Trichoderma viride spores

Novel agroformulations for simultaneous delivery of chemical and biologically active agents to the plants were prepared by encapsulation of Trichoderma viride spores in calcium alginate microspheres.The impact of calcium ions concentration on the viability and sporulation of T.viride spores as well as on the microsphere important physicochemical properties were investigated.Intermolecular interactions in microspheres are complex including mainly hydrogen bonds and electrostatic interactions.T.viride germination inside matrix and germ tubes penetration out of microspheres revealed calcium alginate microspheres provide a supportive environment for T.viride growth.Differences in physicochemical properties and bioactive agents release behaviour from microspheres were ascribed to the changes in microsphere structure.Fitting to Korsmeyer-Peppas empirical model revealed the underlying T.viride release mechanism as anomalous transport kinetics(a combination of two diffusion mechanisms and the Type II transport(polymer swelling and relaxation of the polymeric matrix)).The increasing amount of T.viride spores in the surrounding medium is closely related to the release from microspheres and germination.The rate controlling mechanism of calcium release is Fickian diffusion.A decrease in the release rate with increasing calcium ion concentrations is in accordance with the calcium ions effect on the strength of the alginate network structure.T.viride germination inside microsphere diminished the amount of released calcium ions and slowed release kinetics in comparison with microspheres prepared without T.viride.The results indicated investigated agroformulations have a great potential to be used for plant protection and nutrition.

Novel rechargeable calcium phosphate nanoparticle-containing orthodontic cement

White spot lesions （WSLs）, due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate （NACP） with long-term calcium （Ca） and phosphate （P） ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACP- rechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release. The rechargeable cement consisted of pyromellitic glycerol dimethacrylate （PMGDM） and ethoxylated bisphenol A dimethacrylate （EBPADMA）. NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength （SBS） to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release （P〉 0.1）. Specimens after one recharge treatment （e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as ＂1 min 3 times＂） exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles （P〉 0.1）. The ion re-release concentrations at 14 days versus various recharge treatments were as follows： 1 min 3 times〉3 min 2 times〉 1 min 2 times〉6 min 1 time〉3 min 1 time〉 1 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets.

Effects of MCI-186 on intracellular calcium ion concentration and membrane fluidity of hippocampal neurons in a rat model of Alzheimer's disease

The present study observed the effects of MCI-186 on the intracellular calcium ion concentration （[Ca2＋]i） and membrane fluidity of hippocampal neurons in Alzheimer＇s disease （AD） model rats to validate the neuroprotective effects of MCI-186. Compared with normal and sham-operated rats, the escape latency was obviously prolonged, spanning platform times were obviously reduced, [Ca2＋]i was increased, and microviscosity η value was increased in AD rats. MCI-186 at 0.5 mg/mL and 0.2 mg/mL obviously shortened escape latency, increased spanning platform times and decreased [Ca2＋]i and microviscosity η values in AD rats at 7 and 17 days after induction of the model. The differences in the above-mentioned indices between normal and MCI-186-treated rats were statistically significant. MCI-186 at 0.2 mg/mL yielded better curative effects than 0.5 mg/mL MCI-186. These findings suggest that MCI-186 improves learning and memory abilities in AD rats by decreasing [Ca2＋]i and increasing membrane fluidity of hippocampal neurons.

Negative regulation of gamma-aminobutyric acid type A receptor on free calcium ion levels following facial nerve injury

Previous studies have demonstrated that muscarinic, and nicotinic receptors increase free Ca2＋ levels in the facial nerve nucleus via various channels following facial nerve injury. However, intracellular Ca2＋ overload can trigger either necrotic or apoptotic cell death. Gamma-aminobutyric acid （GABA）, an important inhibitory neurotransmitter in the central nervous system, exists in the facial nerve nucleus. It is assumed that GABA negatively regulates free Ca2＋ levels in the facial nerve nucleus. The present study investigated GABA type A （GABAA） receptor expression in the facial nerve nucleus in a rat model of facial nerve injury using immunohistochemistry and laser confocal microscopy, as well as the regulatory effects of GABAA receptor on nicotinic receptor response following facial nerve injury. Subunits α1, α3, α5, β1, β2, δ, and γ3 of GABAA receptors were expressed in the facial nerve nucleus following facial nerve injury. In addition, GABAA receptor expression significantly inhibited the increase in nicotinic receptor-mediated free Ca2＋ levels in the facial nerve nucleus following facial nerve injury in a concentration-dependent fashion. These results suggest that GABAA receptors exhibit negative effects on nicotinic receptor responses following facial nerve injury.

Muscarinic receptor-mediated calcium changes in a rat model of facial nerve nucleus injury

The muscarinic receptor modulates intracellular free calcium ion levels in the facial nerve nucleus via different channels. In the present study, muscarinic receptor-mediated free calcium ions levels were detected by confocal laser microscopy in the facial nerve nucleus following facial nerve injury in rats. There was no significant difference in muscarinic receptor expression at the affected facial nerve nucleus compared with expression prior to injury, but muscarinic receptor-mediated free calcium ion levels increased in the affected side following facial nerve injury （P 〈 0.01）. At day 30 after facial nerve injury, 50 pmol/L muscarinic-mediated free calcium ion levels were significantly inhibited at the affected facial nerve nucleus in calcium-free artificial cerebrospinal fluid, and the change range was 82% of artificial cerebrospinal fluid （P 〈 0.05）. These results suggest that increased free calcium ion concentrations are achieved by intracellular calcium ion release, and that the transmembrane flow of calcium ions is also involved in this process.

Identification of key pathways and gene expression in the activation of mast cells via calcium flux using bioinformatics analysis

Mast cells are the main effector cells in IgE-associated allergic disorders,and we have reported that mucosal mast cells(MMCs)play a more important role in the development of food allergy(FA).IgE with antigen or calcium ionophore stimulation can lead to the activation of MMCs via a calcium-dependent pathway.The purpose of the present study was to identify gene signatures with IgE/antigen(dinitrophenyl-bovine serum albumin,DNP-BSA)or calcium ionophore(A23187)on the activation of MMCs.Differentially expressed genes between the two types of samples were identified with microarray analysis.Gene ontology functional and pathway enrichment analyses of differentially expressed genes were performed using the database for annotation,visualization,and integrated discovery software.The results showed that IgE/antigen and A23187 could induce degranulation,increase vacuoles,and elevate the cytosolic calcium concentration in MMCs.Furthermore,GeneChip analysis showed that the same 134 mRNAs were altered with IgE/DNP-BSA and A23187,suggesting that DNP-BSA/IgE and A23187 affect the same signal pathway partly in degranulation.KEGG analysis showed that the data were enriched in NF-κB,TNF,MAPK,transcription factor activity,DNA binding,and nucleic acid binding,suggesting that activation of MMCs is a complex process.The results provide new insights on MMCs activation.

T-type calcium channel expression in cultured human neuroblastoma cells

Human neuroblastoma cells （SH-SY5Y） have similar structures and functions as neural cells and have been frequently used for cell culture studies of neural cell functions.Previous studies have revealed L-and N-type calcium channels in SH-SY5Y cells.However,the distribution of the low-voltage activated calcium channel （namely called T-type calcium channel,including Cav3.1,Cav3.2,and Cav3.3） in SH-SY5Y cells remains poorly understood.The present study detected mRNA and protein expres-sion of the T-type calcium channel （Cav3.1,Cav3.2,and Cav3.3） in cultured SH-SY5Y cells using real-time polymerase chain reaction （PCR） and western blot analysis.Results revealed mRNA and protein expression from all three T-type calcium channel subtypes in SH-SY5Y cells.Moreover,Cav3.1 was the predominant T-type calcium channel subtype in SH-SY5Y cells.

Effects of gamma-aminobutyric acid receptors on muscarinic receptor-mediated free calcium ion levels in the facial nucleus following facial nerve injury

Muscarinic receptors and nicotine receptors can increase free calcium ion levels in the facial nucleus via different channels following facial nerve injury. In addition, γ-aminobutyric acid A （GABAA） receptors have been shown to negatively regulate free calcium ion levels in the facial nucleus by inhibiting nicotine receptors. The present study investigated the influence of GABAA, γ-aminobutyric acid B （GABAB） and C （GABAc） receptors on muscarinic receptors in rats with facial nerve injury by confocal laser microscopy. GABAA and GABAB receptors exhibited significant dose-dependent inhibitory effects on increased muscarinic receptor-mediated free calcium ion levels following facial nerve injury. Results showed that GABAA and GABAB receptors negatively regulate muscarinic receptor effects and interplay with cholinergic receptors to regulate free calcium ion levels for facial neural regeneration.

Langmuir-Blodgett Films and Calcium Ion Coordination of Biliverdin and Its Amphiphilic Derivatives

Monolayer formation and LB film fabrication of amphiphilic derivative of biliverdin 1, diododecyl biliverdinamide [B(CONHC12H25)(2), 2] at an air-water interface on pure water subphase and subphase containing calcium ion were investigated and compared with 1. The coordination in ordered molecular films is much different from that in bulk solution. The formation of ligand-calcium complex was confirmed by X-ray photoelectron spectroscopy.

Role of Calcium Ion in Apoptosis of MD Cancer Cells Induced by Arsenic Trioxide

In order to observe the role of calcium ion in apoptosis of MD cancer cells induced by arsenic trioxide, inhibition percentage was detected by MTT assay; morphology changes were examined by fluorescence microscope; apoptosis was examined by DNA Ladder; [Ca^2＋]i was investigated by spectrofluorimeter in vitro on MDCC-MSB 1 cells. The results showed that As2O3 inhibited the proliferation of MDCC-MSB1 cells in concentration dependent manner （P〈0.05 or P〈0.01）; typical apoptosis character was observed by fluorescence microscope; DNA Ladder was observed; the [Ca^2＋]i was elevated significantly after the treatment of As203 （P〈0.05 or P〈0.01） and showed a dose-dependent manner. It is concluded that the calcium may play an important role in apoptosis of MD cancer cells induced by arsenic trioxide.

Droplet microfluidic chip for precise monitoring of dynamic solution changes

In this work,an automated microfluidic chip that uses negative pressure to sample and analyze solutions with high temporal resolution was developed.The chip has a T-shaped channel for mixing the sample with a fluorescent indicator,a flow-focusing channel for generating droplets in oil,and a long storage channel for incubating and detecting the droplets.By monitoring the fluorescence intensity of the droplets,the device could detect changes in solution accurately over time.The chip can generate droplets at frequencies of up to 42 Hz with a mixing ratio of 1:1 and a temporal resolution of 3–6 s.It had excellent linearity in detecting fluorescein solution in the concentration range 1–5μM.This droplet microfluidic chip provides several advantages over traditional methods,including high temporal resolution,stable droplet generation,and faster flow rates.This approach could be applied to monitoring calcium ions with a dynamic range from 102 to 107 nM and a detection limit of 10 nM.

Swelling Studies and in vitro Release of Acemetacin and BSA from Alginate Gel Beads Crosslinked with Ca^(2+) or Ba^(2+)

The aim of the present work was to investigate the swelling behavior and the in vitro release of acemetacin and bovine serum albumin from alginate gel beads crosslinked with Ca2＋ or Ba2＋. The release profiles suggested that the extent of swelling of the alginate beads played an important role in the release of drug. Small drugs are mainly released via diffusion through the alginate gel matrix. Compared with small drugs, large molecule drugs are difficult to diffuse through the pores of the matrix bead until the beads swell to a certain extent to provide enough large pores. The Ba2＋ crosslinked alginate beads showed slower release rate compared with the Ca2＋ crosslinked alginate beads, whether loaded the large molecules or small drugs. In conclusion, the Ba2＋ crosslinked alginate beads are considered more suitable than Ca2＋ crosslinked alginate beads for using as a sustained release vehicle especially for large molecule drugs.

K+alkalization promoted Ca2+intercalation in V2CTx MXene for enhanced Li storage

Although MXenes is highly attractive as anode materials of lithium ion batteries,it sets a bottleneck for higher capacity of the V2CTxMXene due to the limited interlayer space and the derived surface terminations.Herein,the cation intercalation and ion-exchange were well employed to achieve a K+and Ca2+intercalated V2CTxMXene.A larger interlayer distance and low F surface terminations were thereof obtained,which accelerates the ion transport and promotes the delicate surface of V2CTx MXene.As a result,a package of enhanced capacity,rate performance and cyclability can be achieved.Furthermore,the ion exchange approach can be extended to other 2 D layered materials,and both the interlayer control and the surface modification will be achieved.

The calmodulin-dependent protein kinase II inhibitor KN-93 protects rat cerebral cortical neurons from N-methyl-D-aspartic acid-induced injury

In this study, primary cultured cerebral cortical neurons of Sprague-Dawley neonatal rats were treated with 0.25, 0.5, and 1.0 μM calmodulin-dependent protein kinase II inhibitor KN-93 after 50 μM N-methyI-D-aspartic acid-induced injury. Results showed that, compared with N-methyi-D- aspartic acid-induced injury neurons, the activity of cells markedly increased, apoptosis was significantly reduced, leakage of lactate dehydrogenase decreased, and intracellular Ca2＋ concentrations in neurons reduced after KN-93 treatment. The expression of caspase-3, phosphorylated calmodulin-dependent protein kinase II and total calmodulin-dependent protein kinase II protein decreased after KN-93 treatment. And the effect was apparent at a dose of 1.0 pM KN-93. Experimental findings suggest that KN-93 can induce a dose-dependent neuroprotective effect, and that the underlying mechanism may be related to the down-regulation of caspase-3 and calmodulin- dependent protein kinase II expression.

Effects of 1,2,4-Trichlorobenzene and Mercury Ion Stress on Ca^2+ Fluxion and Protein Phosphorylation in Rice

The effects of 5 mg/L 1,2,4-trichlorobenzene （TCB） and 0.1 mmol/L mercury ion （Hg^2＋） stresses on Ca^2＋ fluxion and protein phosphorylation in rice seedlings were investigated by isotope exchange kinetics and in vitro phosphorylation assay. The Ca^2＋ absorption in rice leaves and Ca^2＋ transportation from roots to leaves were promoted significantly in response to Hg^2＋ and TCB treatments for 4-48 h. The Ca^2＋ absorption peaks presented in the leaves when the rice seedlings were exposed to Hg^2＋ for 8-12 h or to TCB for 12-24 h. Several Ca^2＋ absorption peaks presented in the roots during rice seedlings being exposed to Hg^2＋ and TCB, and the first Ca^2＋ absorption peak was at 8 h after being exposed to Hg^2＋ and TCB The result of isotope exchange kinetic analysis confirmed that short-term （8 h） Hg^2＋ and TCB stresses caused Ca^2＋ channels or pumps located on plasmalemma to open transiently. The phosphorylation assay showed that short-term TCB stress enhanced protein phosphorylation in rice roots （TCB treatment for 4-8 h） and leaves （TCB treatment for 4-24 h）, and short-term （4-8 h） Hg^2＋ stress also enhanced protein phosphorylation in rice leaves. The enhancement of protein phosphorylation in both roots and leaves corresponded with the first Ca^2＋ absorption peak, which confirmed that the enhancement of protein phosphorylation caused by TCB or Hg^2＋ stress might be partly triggered by the increases of cytosolic calcium. TCB treatment over 12 h inhibited protein phosphorylation in rice roots, which might be partly due to that TCB stress suppressed the protein kinase activity. Whereas, Hg^2＋ treatment inhibited protein phosphorylation in rice roots, and Hg^2＋ treatment over 12 h inhibited protein phosphorylation in rice leaves. This might be attributed to that not only the protein kinase activity, but also the expressions of phosphorylation proteins were restrained by Hg^2＋ stress.