Rationale:This case report describes a couple with recurrent fertilization failure despite undergoing multiple cycles of intracytoplasmic sperm injection(ICSI).The principal clinical concern was suspected oocyte activ...Rationale:This case report describes a couple with recurrent fertilization failure despite undergoing multiple cycles of intracytoplasmic sperm injection(ICSI).The principal clinical concern was suspected oocyte activation deficiency(OAD),in which fertilization is impeded due to the oocyte’s inability to initiate embryogenesis,commonly attributed to inadequate intracellular calcium(Ca^(2+))release following sperm injection.Patient concerns:The couple repeatedly experienced complete or near-complete fertilization failure in previous ICSI cycles,raising suspicion of an underlying oocyte activation defect.Diagnosis:Based on the repeated absence of fertilization post-ICSI and clinical history,a diagnosis of suspected OAD leading to recurrent ICSI fertilization failure was considered.Interventions:Artificial oocyte activation(AOA)using the calcium ionophore A23187 was performed.After ICSI,unfertilized oocytes were exposed to the ionophore to induce Ca^(2+)influx,simulating physiological calcium oscillations essential for oocyte activation.The efficacy of intervention was evaluated through subsequent embryonic development,morphological grading,and chromosomal integrity.Outcomes:Following AOA treatment,successful oocyte activation occurred,resulting in the formation of high-grade embryos with normal developmental progression.Chromosomal analysis revealed no detectable abnormalities,indicating genomic stability.Lessons:Calcium ionophore–mediated AOA may serve as an effective adjunct in cases of recurrent ICSI failure attributed to OAD.This case highlights the importance of individualized therapeutic strategies in assisted reproduction;however,further research is needed to refine protocols,validate broader clinical efficacy,and assess long-term safety,including potential epigenetic risks.展开更多
Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effe...Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effect on the selectivity and sensitivity to Ag^+ ions.The electrode based on ionophore 9,10,20,25-tetrahydro-5H,12H-tribenzo[b,n,r][1,7,10,16,4,13]tetrathiadiaza cycloicosine 6,13-(7H,14H)-dione(C) with 2-nitrophenyl octyl ether(o-NPOE) as solvent in a poly(vinyl chloride)(PVC) membrane matrix sho...展开更多
Timing of vegetal-endodermal cell determination in amphioxus embryos remains uncertain. We tentatively testal effects of A23187, the calcium ionophore, on the deveopment of vegetal blastomeres isolated at the 16-cell ...Timing of vegetal-endodermal cell determination in amphioxus embryos remains uncertain. We tentatively testal effects of A23187, the calcium ionophore, on the deveopment of vegetal blastomeres isolated at the 16-cell stage. It was found that when vegetal blastomres committed to endodermwere treated with A23187 prior to gastrulation, they were transformed into ectodermal cells as evidenced by the cell morphology and function characteristic of epidermis. Howver, the developmental fate of the sam blastomeres untreated or treated with DMSO at the same stage or of those treated with A23187 after gastrulation remained unchanged. Thus, vegetal-endodermal cells in amphioxus embryos are not irreversibly deermined before the gastrula stage, and artificial incarease in intracelluar Ca2+ concentration can induce transdetermination of the predetermined endodermal cells into ectodermal cells.展开更多
A new type of di benzoyl tartaric acid selective electr ode has been developed. Three double\| arm calixarene derivatives were emp loyed as the neutral ionophores. The poly(vinyl chloride) me...A new type of di benzoyl tartaric acid selective electr ode has been developed. Three double\| arm calixarene derivatives were emp loyed as the neutral ionophores. The poly(vinyl chloride) membrane electrode containing an amide derivative of ca lixarene as the neutral carrier an d a dibutyl phthalate as the plastici zer exhibited the highest sensitivity for dibenzoyl tartaric acid. The slop e of linear portion was 27.8 mV per c oncertration decade. The electrode has a fast response and a long lifetime .展开更多
A thiocyanate ion selective poly(aniline) solid contact electrode based on manganese complex of N,N’-bis-(4-phenylazosalicylidene)-o-phenylene diamine ionophore was successfully developed. The electrode exhibits a go...A thiocyanate ion selective poly(aniline) solid contact electrode based on manganese complex of N,N’-bis-(4-phenylazosalicylidene)-o-phenylene diamine ionophore was successfully developed. The electrode exhibits a good linear response of 58.1 mV/decade (at 20?C ± 0.2?C, r2 = 0.998) with in the concentration range of 1 × 10–1.0 ~ 1 × 10–5.8 M thiocyanate solution. The composition of this electrode was: ionophore 0.040, polyvinylchloride 0.300, dibutylphthalate 0.660 (mass). This dibutylphthalate plasticizer provides the best response characteristics. The electrode shows good selectivity for thiocyanate ion in comparison with any other anions and is suitable for use with aqueous solutions of pH 4.0 ~ 6.0. The standard deviations of the measured emf difference were ±1.70 and ±2.01 mV for thiocyanate sample solutions of 1.0 × 10–2 M and 1.0 × 10–3 M, respectively. The stabilization time was less than 170 sec. and response time was less than 17 sec.展开更多
<strong>Objectives:</strong><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> Evaluate the effect of ...<strong>Objectives:</strong><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> Evaluate the effect of artificial oocyte activation (AOA) using calcium ionophore (A23187) on the rate of fertilization and cleavage of embryos in surgically retrieved sperm of patients with non-obstructive azoospermia undergoing intracytoplasmic sperm injection (ICSI).</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;">Study design: </span></b></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">This study was conducted on 60 infertile couples undergoing ICSI cycles as a randomized controlled parallel group’s experimental study in a private IVF center in Egypt from January 2018 to July 2019. ICSI cycles were divided into two g</span><span style="font-family:Verdana;">roups: Group A: includes 30 ICSI patients with surgically retrieved sperms of non-obstructive azoospermia treated with calcium ionophore (A23187). Group C/Control: includes 30 ICSI patients with surgically retrieved sperms of non-obstructive azoospermia non-treated with calcium ionophore (A23187)</span><span style="font-family:Verdana;">. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">There was no statistical difference between both groups regarding the fertilization rate (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.853). There was no statistical difference between them regarding implantation rate (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.237). The percentage of Class A embryos in the ca ionophore group was 81.7%, while it was 82.8% in the control group. There was insignificant difference between them (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.782). There was no statistical significant difference between the two groups regarding the clinical pregnancy rate</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> it was (56.7%) in the ca ionophore group while it was (53.3%) in the control group.</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;">Conclusion: </span></b></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">AOA by Ca</span><sup><span style="font-family:Verdana;">2++</span></sup></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ionophore didn’t improve the outcome of ICSI cycle in cases of non obstructive azoospermia in terms of fertilization, implantation and pregnancy rate.</span></span></span>展开更多
The release of mediators from mast cells is a model for cell secretion and is an in-vitro index for immediate hypersensitivity reactions. Calcium influx is generally accepted to be the primary biochemicalevent in mast...The release of mediators from mast cells is a model for cell secretion and is an in-vitro index for immediate hypersensitivity reactions. Calcium influx is generally accepted to be the primary biochemicalevent in mast cell activation.We studied the effect of the calcium ionophore A 23187 and calcium channelblockers,nifedipine and verapamil, in triggering the activation of rat peritoneal mast cells.At suitableconcentration nifedipine and verapamil have had the inhibition effect in the IgE-dependent roaction.展开更多
Ionophore can prominently improve the ion permeability of cell membrane and disrupt cellular ion homeostasis.Most studies regarding ionophore facilitating ion transmembrane transport focus on artificial liquid-liquid ...Ionophore can prominently improve the ion permeability of cell membrane and disrupt cellular ion homeostasis.Most studies regarding ionophore facilitating ion transmembrane transport focus on artificial liquid-liquid interfaces,which have large difference from the actual environment of cell membrane.Here,we construct a supported lipid bilayeron a gold nanoparticles film modified ZnSe prism as an appropriate model of cell membrane to investigate the dynamic of the ion transport facilitated by ionophore using surface enhanced infrared absorption spectroscopy(SEIRAS).We find that the ion transmembrane transport consists of two steps:The ion transmembrane transport starts with the association/disassociation between ion and ionophore at the edge of lipid bilayer;The second step is the transfer of ion-ionophore complex across lipid bilayer.Our results show that the complex transfer across the lipid bilayer is the rate determining step.展开更多
Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- m...Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- mide (PAA)—ionophores III and IV, respectively were prepared. The all solid-state sensors were constructed by the application of a thin film of a polymer cocktail containing a phthalocyanine ionophore and cetyltrimethylammonium bromide (CTMAB) as a lipophilic cationic additive onto a gold electrode precoated with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) as an ion and electron transducer. The sensor with 10.3% of ionophore (III) covalently attached to plasticizer-free poly (butyl methacrylate-co-do- decyl methacrylate) (PBDA) exhibited a good selectivity for perchlorate and discriminated many ions, in- cluding F–, Cl–, Br–, I–, SCN–, , S2– and . The covalent attachment of the ionophore to the polymer resulted in a near-Nernstian anionic slope of –62.3 mV/decade whereas a super-Nernstian slope of –79.9 mV/ decade was obtained for the free ionophore. The sensor covered a linear concentration range of 5 × 10–9 - 1 × 10–2 mol?L–1 with a lower detection limit (LDL) of 1 × 10–9 mol?L–1 and gave a stable response over a pH range of 4 - 10.5. The all-solid state sensors were utilized for the selective flow injection potentiometric determination of perchlorate in natural water and human urine samples in the nanomolar concentration range.展开更多
Macrocyclic compounds,such as crown ethers,azacrown ethers,thiacrown ethers,calixarenes and porphyrins,which act as ionophores in lead(Ⅱ)ion-selective electrodes,are systematically summarized based on the latest lite...Macrocyclic compounds,such as crown ethers,azacrown ethers,thiacrown ethers,calixarenes and porphyrins,which act as ionophores in lead(Ⅱ)ion-selective electrodes,are systematically summarized based on the latest literatures.The molecular structure characteristics of the ionophores are general-ized.The modification regulations for the substituted ionophores are elaborated with the purpose of improving the response features of the lead(Ⅱ)ion-selective electrodes assembled by them.It is pointed out that the introduction of pendant moieties which contain soft base coordination centers like N,S and P atoms is in favor of adjusting the cavity size and conformation of the macrocyclic com-pounds.Furthermore,there is synergic effect between the cavity and the donor sites of the ligand and thus the selective complexation of lead ions is easily realized,resulting in significant avoidance of the interference from other metal ions.The macrocyclic ionophore having the best response characteris-tics thus far was found to be N,N'-dimethylcyanodiaza-18-crown-6 with the detection limit of 7.0×10-8(14.5μg/L),which is one of the uncommon ionophores that can really eliminate the interference from silver and mercury ions.The selectivity coefficients of the ionophore for lead ions over other metal ions,such as alkali,alkaline earth and transition metal ions are in the order of 10-4 or smaller,where the se-lectivity coefficient of lead(Ⅱ)over mercury(Ⅱ)ions is much lower,down to 8.9×10-4.The structure de-sign idea for high-performance ionophore is proposed according to present results.The incorporation of nitrogen atom,especially cyano group or thiocyano group or amino/imino groups,rather than thio atom alone could result in new excellent lead ionophores.The aborative design for metacyclophanes containing aromatic nitrogen atoms with the aim of creating excellent ionophores would also become a potential research trend.The lead(Ⅱ)ion-selective electrodes have shown widely potential applications in the potentiometric titration,and flow injection potentiometry,and in the direct determination of lead in stack emissions of lead smelters,and assay of lead in rocks,particularly in the direct measurements of trace amount of lead(Ⅱ)in human hair,blood,edible oil,food,water,and air.展开更多
Benzil bis(carbohydrazone)(BBC) is prepared and explored as new N N Schiff's base, which plays the role of an excellent ion carrier in the construction of a Cd(II) ion membrane sensor. The tris(2-ethylhexyl) phosp...Benzil bis(carbohydrazone)(BBC) is prepared and explored as new N N Schiff's base, which plays the role of an excellent ion carrier in the construction of a Cd(II) ion membrane sensor. The tris(2-ethylhexyl) phosphate best performance corresponds to a membrane composition of 30% poly(vinyl chloride), 65%(TEHP), 3.5% BBC and 1.5% tetradodecyl-ammoniumtetrakis(4-chlorophenyl) borate(ETH 500). This sensor shows very good selectivity and sensitivity towards cadmium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition, selectivity, pH and influence of additive on the response properties of electrode were investigated. The response mechanism was discussed in the view of UV-spectroscopy. The electrode exhibits a Nernstian behavior(with slope of 29.7 mV per decade) over a very wide concentration range from 1.0×10?1 to 1.0×10?8 mol·L?1 with a detection limit of 3.2×10?8 mol·L?1. It shows rela-tively fast response time in whole concentration range(<8 s) and can be used for at least 10 weeks in the pH range of 2.0-9.0. The proposed sensor is successfully used for the determination of cadmium in different chocolate sam-ples and as indicator electrode in titration with ethylene diamine tetraacetate(EDTA).展开更多
Both calcium ionophore A23187 and endoplasmic reticulum Ca2+- ATPase inhibitor thapsigargin (Tg) could increase intracellular free calcium concentration and induce apoptosis in some cell lines. In the present study, w...Both calcium ionophore A23187 and endoplasmic reticulum Ca2+- ATPase inhibitor thapsigargin (Tg) could increase intracellular free calcium concentration and induce apoptosis in some cell lines. In the present study, we found that HL-60 cells treated with A23187 (1μg/ml) for 4 h or with Tg (0.5μg/ml) for 2 h showed typical characteristics of apoptosis. Pretreatment with nontoxic concentration of cyclosporin A (CsA) (1μg/ml) Could block these effects. Flow cytometric analysis of intracellular Ca2+ after staining with fluo-3 AM showed that CsA did not prevent the increase of intracellular calcium induced by A23187 or Tg, but it could maintain the high level of intracellular Ca2+ for a long time. These results suggest that CsA may prevent calcium- induced apoptosis by blocking the transportation of Ca2+ in HL-60cells.展开更多
We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then ...We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then the chlorine ion selective membrane is formed on the sensing window,and the fabrication of the EGFET chlorine ion sensing device is completed.The surface potential on the sensing membrane of the EGFET chlorine ion sensing device will be changed in the different chlorine ion concentration solutions,then changes further gate voltage and drain current to detect chlorine ion concentration.We will study non-ideal effects such as temperature,hysteresis and drift effects for the EGFET chlorine ion sensing device in this paper,these researches will help us to improve the sensing characteristics of the EGFET chlorine ion sensing device.展开更多
A new chemically modified carbon paste electrode for cesium(I) ion determination based on potassium zinc hexacyan-oferrate (PZHCF) as an ionophore was prepared. The electrode exhibits a Nernstian response for Cs(I) io...A new chemically modified carbon paste electrode for cesium(I) ion determination based on potassium zinc hexacyan-oferrate (PZHCF) as an ionophore was prepared. The electrode exhibits a Nernstian response for Cs(I) ions over a wide concentration range from 1 × 10-6 to 1 × 10-1 mol·L-1 with a slope of 58 ± 0.5 mV·decade-1. It has a response time of about 35 s and can be used for a period of 3 months with good reproducibility. Detection limit obtained in the optimal conditions was 3 × 10-7 mol·L-1. The potentiometric response is independent of the pH of the solution in the pH range 4.0 - 8.0. The electrode possesses the advantages of low resistance, fast response over a variety of other cations. The proposed electrode is applied as a sensor for the determination of Cs(I) ion concentration in different samples solutions. The results showed a good correlation with the data obtained by atomic absorption spectrometric method.展开更多
A novel calix[4]arene derivative 2 with amino functional groups at the lower rim was first prepared via introduction of nitro functional groups and amination of the dinitro derivative of calix[4]arene. The optically a...A novel calix[4]arene derivative 2 with amino functional groups at the lower rim was first prepared via introduction of nitro functional groups and amination of the dinitro derivative of calix[4]arene. The optically active monomers were synthesized by dehydration of L-leucine （and L-isoleucine） and 3,3＇,4,4＇-benzophenonetetracarboxylic- 3,3＇,4,4＇-dianhydride （3） followed by reaction with thionyl chloride to form 5a and 5b. Two methods, polymerization under microwave irradiation and solution polymerization in CH2Cl2/TEA, were then employed to carry out the condensation polymerization of 2 with the optically active monomers 5a and 5b, respectively. The polymerization conditions affected the kind of resulting polymers, poly（amide-imide）s （PAIs） 6a and 6b and poly（ester-imide）s （PEIs） 6a＇ and 6b＇ were obtained selectively in good yields and moderate inherent viscosities. Sorption-extraction experiments were carried out using cram picrate extraction method and verified good binding ability of the resulting calixarene-based polymers towards silver, alkali metal and toxic heavy metal cations. Also thermogravimetric analysis indicated that the resulting PAIs and PEIs were thermally stable.展开更多
Three novel amprolium HCl（AMP）-selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride（PVC）. Sensor I was fabricated using potassium tetra...Three novel amprolium HCl（AMP）-selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride（PVC）. Sensor I was fabricated using potassium tetrakis（4-chlorophenyl） borate（Tp ClPB） as a cationic exchanger without incorporation of an ionophore.Sensor Ⅱ used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor Ⅲ used p-tert-butylcalix[8]arene as an ionophore. The three proposed sensors showed Nernestian response slopes of 29.2±0.8,29.3±0.6 and 30.2±0.4 m V/decade over the concentration range from 10–6 to 10–2 mol L_（-1）,respectively. The proposed sensors displayed useful analytical characteristics for the determination of AMP in bulk powder, different pharmaceutical formulations, and chicken liver and in the presence of ethopabate. The proposed method was validated according to ICH guidelines for its linearity, accuracy,precision and robustness.展开更多
A modified method of preparing crown functionalized linear polysiloxane has been described. 4'-Allyldibenzo-18-crown-6 was subjected to hydrosilylation with methyldichlorosilane, followed by polycondensation with ...A modified method of preparing crown functionalized linear polysiloxane has been described. 4'-Allyldibenzo-18-crown-6 was subjected to hydrosilylation with methyldichlorosilane, followed by polycondensation with silanol-terminated polydimethylsiloxane to give the title crown functionalized linear polysiloxane. The transport properties of sodium, potassium, and ammonium salt through a bulk liquid membrane system using the new type of crown functionalized linear polysiloxane as a carrier were investigated. It is worthy to point out that the carrier can be used repeatedly at least six runs with no apparent change in the transport rate of potassium ion.展开更多
Objective: To study the role of apoptosis in tumor cell of malignant glioma death following treatment with hyperthermia and calcium ionophore. Methods: The apoptosis induced by hyperthermia and calcium ionophore, A231...Objective: To study the role of apoptosis in tumor cell of malignant glioma death following treatment with hyperthermia and calcium ionophore. Methods: The apoptosis induced by hyperthermia and calcium ionophore, A23187, in human glioblastoma cell line TJ905 and murine glioblastoma G422 was evaluated by characteristic findings in DNA agarose gel electrophresis, ultrastructural examination and flow cytometric analysis. Results: Apoptosis could be induced by moderate hyperthermia, but not by mild hyperthermia, calcium ionophore enhanced significantly the effect of mild hyperthermia on the induction of apoptosis. Conclusion: This result indicates that apoptotic cell death is one of the mechanisms of hyperthermic therapy for malignant glioma and taking measures to increase the cytolic calcium may enhance the effect of hyperthermia.展开更多
Ionophores consist of molecules which surround and carry positive metal ions and other ions through biological membranes. One classe of ionophores which we have been developing contains dipeptides which are encouraged...Ionophores consist of molecules which surround and carry positive metal ions and other ions through biological membranes. One classe of ionophores which we have been developing contains dipeptides which are encouraged to become part of a ring because of possible hydrogen bond formation between the 2-hydroxy on the phenyl group and carboxyl group (COOH) of the final amide proline. Formation of a ring should increase the complexation ability of the ionophore. We report that the synthesis of N-(2-hydroxyl-1-phenoxyacetyl) prolyproline(1), a novel ionophore is prepared from activated 2-acetoxy phenoxyacetic acid (3a) and the appropriate dipeptide ester using coupling methods such as dicyclohexyl carbodiimide with hydroxyben-ztriazole or carbonyl diimidazole.展开更多
文摘Rationale:This case report describes a couple with recurrent fertilization failure despite undergoing multiple cycles of intracytoplasmic sperm injection(ICSI).The principal clinical concern was suspected oocyte activation deficiency(OAD),in which fertilization is impeded due to the oocyte’s inability to initiate embryogenesis,commonly attributed to inadequate intracellular calcium(Ca^(2+))release following sperm injection.Patient concerns:The couple repeatedly experienced complete or near-complete fertilization failure in previous ICSI cycles,raising suspicion of an underlying oocyte activation defect.Diagnosis:Based on the repeated absence of fertilization post-ICSI and clinical history,a diagnosis of suspected OAD leading to recurrent ICSI fertilization failure was considered.Interventions:Artificial oocyte activation(AOA)using the calcium ionophore A23187 was performed.After ICSI,unfertilized oocytes were exposed to the ionophore to induce Ca^(2+)influx,simulating physiological calcium oscillations essential for oocyte activation.The efficacy of intervention was evaluated through subsequent embryonic development,morphological grading,and chromosomal integrity.Outcomes:Following AOA treatment,successful oocyte activation occurred,resulting in the formation of high-grade embryos with normal developmental progression.Chromosomal analysis revealed no detectable abnormalities,indicating genomic stability.Lessons:Calcium ionophore–mediated AOA may serve as an effective adjunct in cases of recurrent ICSI failure attributed to OAD.This case highlights the importance of individualized therapeutic strategies in assisted reproduction;however,further research is needed to refine protocols,validate broader clinical efficacy,and assess long-term safety,including potential epigenetic risks.
基金supported by the Chinese Academy of Sciences(No.KZCX2-YW-410)the National Natural Science Foundation of China(No.40776058)+1 种基金the National 863 High Technology Project of the Ministry of Science and Technology of China(No.2007AA09Z103)the Outstanding Youth Natural Science Foundation of Shandong Province(No.JQ200814)
文摘Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effect on the selectivity and sensitivity to Ag^+ ions.The electrode based on ionophore 9,10,20,25-tetrahydro-5H,12H-tribenzo[b,n,r][1,7,10,16,4,13]tetrathiadiaza cycloicosine 6,13-(7H,14H)-dione(C) with 2-nitrophenyl octyl ether(o-NPOE) as solvent in a poly(vinyl chloride)(PVC) membrane matrix sho...
文摘Timing of vegetal-endodermal cell determination in amphioxus embryos remains uncertain. We tentatively testal effects of A23187, the calcium ionophore, on the deveopment of vegetal blastomeres isolated at the 16-cell stage. It was found that when vegetal blastomres committed to endodermwere treated with A23187 prior to gastrulation, they were transformed into ectodermal cells as evidenced by the cell morphology and function characteristic of epidermis. Howver, the developmental fate of the sam blastomeres untreated or treated with DMSO at the same stage or of those treated with A23187 after gastrulation remained unchanged. Thus, vegetal-endodermal cells in amphioxus embryos are not irreversibly deermined before the gastrula stage, and artificial incarease in intracelluar Ca2+ concentration can induce transdetermination of the predetermined endodermal cells into ectodermal cells.
文摘A new type of di benzoyl tartaric acid selective electr ode has been developed. Three double\| arm calixarene derivatives were emp loyed as the neutral ionophores. The poly(vinyl chloride) membrane electrode containing an amide derivative of ca lixarene as the neutral carrier an d a dibutyl phthalate as the plastici zer exhibited the highest sensitivity for dibenzoyl tartaric acid. The slop e of linear portion was 27.8 mV per c oncertration decade. The electrode has a fast response and a long lifetime .
文摘A thiocyanate ion selective poly(aniline) solid contact electrode based on manganese complex of N,N’-bis-(4-phenylazosalicylidene)-o-phenylene diamine ionophore was successfully developed. The electrode exhibits a good linear response of 58.1 mV/decade (at 20?C ± 0.2?C, r2 = 0.998) with in the concentration range of 1 × 10–1.0 ~ 1 × 10–5.8 M thiocyanate solution. The composition of this electrode was: ionophore 0.040, polyvinylchloride 0.300, dibutylphthalate 0.660 (mass). This dibutylphthalate plasticizer provides the best response characteristics. The electrode shows good selectivity for thiocyanate ion in comparison with any other anions and is suitable for use with aqueous solutions of pH 4.0 ~ 6.0. The standard deviations of the measured emf difference were ±1.70 and ±2.01 mV for thiocyanate sample solutions of 1.0 × 10–2 M and 1.0 × 10–3 M, respectively. The stabilization time was less than 170 sec. and response time was less than 17 sec.
文摘<strong>Objectives:</strong><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> Evaluate the effect of artificial oocyte activation (AOA) using calcium ionophore (A23187) on the rate of fertilization and cleavage of embryos in surgically retrieved sperm of patients with non-obstructive azoospermia undergoing intracytoplasmic sperm injection (ICSI).</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;">Study design: </span></b></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">This study was conducted on 60 infertile couples undergoing ICSI cycles as a randomized controlled parallel group’s experimental study in a private IVF center in Egypt from January 2018 to July 2019. ICSI cycles were divided into two g</span><span style="font-family:Verdana;">roups: Group A: includes 30 ICSI patients with surgically retrieved sperms of non-obstructive azoospermia treated with calcium ionophore (A23187). Group C/Control: includes 30 ICSI patients with surgically retrieved sperms of non-obstructive azoospermia non-treated with calcium ionophore (A23187)</span><span style="font-family:Verdana;">. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">There was no statistical difference between both groups regarding the fertilization rate (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.853). There was no statistical difference between them regarding implantation rate (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.237). The percentage of Class A embryos in the ca ionophore group was 81.7%, while it was 82.8% in the control group. There was insignificant difference between them (</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> = 0.782). There was no statistical significant difference between the two groups regarding the clinical pregnancy rate</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> it was (56.7%) in the ca ionophore group while it was (53.3%) in the control group.</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;">Conclusion: </span></b></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">AOA by Ca</span><sup><span style="font-family:Verdana;">2++</span></sup></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ionophore didn’t improve the outcome of ICSI cycle in cases of non obstructive azoospermia in terms of fertilization, implantation and pregnancy rate.</span></span></span>
文摘The release of mediators from mast cells is a model for cell secretion and is an in-vitro index for immediate hypersensitivity reactions. Calcium influx is generally accepted to be the primary biochemicalevent in mast cell activation.We studied the effect of the calcium ionophore A 23187 and calcium channelblockers,nifedipine and verapamil, in triggering the activation of rat peritoneal mast cells.At suitableconcentration nifedipine and verapamil have had the inhibition effect in the IgE-dependent roaction.
基金supported by grants from the National Key R&D Program of China(No.2017YFA0700500)the National Natural Science Foundation of China(No.21635004)。
文摘Ionophore can prominently improve the ion permeability of cell membrane and disrupt cellular ion homeostasis.Most studies regarding ionophore facilitating ion transmembrane transport focus on artificial liquid-liquid interfaces,which have large difference from the actual environment of cell membrane.Here,we construct a supported lipid bilayeron a gold nanoparticles film modified ZnSe prism as an appropriate model of cell membrane to investigate the dynamic of the ion transport facilitated by ionophore using surface enhanced infrared absorption spectroscopy(SEIRAS).We find that the ion transmembrane transport consists of two steps:The ion transmembrane transport starts with the association/disassociation between ion and ionophore at the edge of lipid bilayer;The second step is the transfer of ion-ionophore complex across lipid bilayer.Our results show that the complex transfer across the lipid bilayer is the rate determining step.
文摘Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- mide (PAA)—ionophores III and IV, respectively were prepared. The all solid-state sensors were constructed by the application of a thin film of a polymer cocktail containing a phthalocyanine ionophore and cetyltrimethylammonium bromide (CTMAB) as a lipophilic cationic additive onto a gold electrode precoated with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) as an ion and electron transducer. The sensor with 10.3% of ionophore (III) covalently attached to plasticizer-free poly (butyl methacrylate-co-do- decyl methacrylate) (PBDA) exhibited a good selectivity for perchlorate and discriminated many ions, in- cluding F–, Cl–, Br–, I–, SCN–, , S2– and . The covalent attachment of the ionophore to the polymer resulted in a near-Nernstian anionic slope of –62.3 mV/decade whereas a super-Nernstian slope of –79.9 mV/ decade was obtained for the free ionophore. The sensor covered a linear concentration range of 5 × 10–9 - 1 × 10–2 mol?L–1 with a lower detection limit (LDL) of 1 × 10–9 mol?L–1 and gave a stable response over a pH range of 4 - 10.5. The all-solid state sensors were utilized for the selective flow injection potentiometric determination of perchlorate in natural water and human urine samples in the nanomolar concentration range.
基金the National Natural Science Foundation of China(Grant No.20774065)
文摘Macrocyclic compounds,such as crown ethers,azacrown ethers,thiacrown ethers,calixarenes and porphyrins,which act as ionophores in lead(Ⅱ)ion-selective electrodes,are systematically summarized based on the latest literatures.The molecular structure characteristics of the ionophores are general-ized.The modification regulations for the substituted ionophores are elaborated with the purpose of improving the response features of the lead(Ⅱ)ion-selective electrodes assembled by them.It is pointed out that the introduction of pendant moieties which contain soft base coordination centers like N,S and P atoms is in favor of adjusting the cavity size and conformation of the macrocyclic com-pounds.Furthermore,there is synergic effect between the cavity and the donor sites of the ligand and thus the selective complexation of lead ions is easily realized,resulting in significant avoidance of the interference from other metal ions.The macrocyclic ionophore having the best response characteris-tics thus far was found to be N,N'-dimethylcyanodiaza-18-crown-6 with the detection limit of 7.0×10-8(14.5μg/L),which is one of the uncommon ionophores that can really eliminate the interference from silver and mercury ions.The selectivity coefficients of the ionophore for lead ions over other metal ions,such as alkali,alkaline earth and transition metal ions are in the order of 10-4 or smaller,where the se-lectivity coefficient of lead(Ⅱ)over mercury(Ⅱ)ions is much lower,down to 8.9×10-4.The structure de-sign idea for high-performance ionophore is proposed according to present results.The incorporation of nitrogen atom,especially cyano group or thiocyano group or amino/imino groups,rather than thio atom alone could result in new excellent lead ionophores.The aborative design for metacyclophanes containing aromatic nitrogen atoms with the aim of creating excellent ionophores would also become a potential research trend.The lead(Ⅱ)ion-selective electrodes have shown widely potential applications in the potentiometric titration,and flow injection potentiometry,and in the direct determination of lead in stack emissions of lead smelters,and assay of lead in rocks,particularly in the direct measurements of trace amount of lead(Ⅱ)in human hair,blood,edible oil,food,water,and air.
文摘Benzil bis(carbohydrazone)(BBC) is prepared and explored as new N N Schiff's base, which plays the role of an excellent ion carrier in the construction of a Cd(II) ion membrane sensor. The tris(2-ethylhexyl) phosphate best performance corresponds to a membrane composition of 30% poly(vinyl chloride), 65%(TEHP), 3.5% BBC and 1.5% tetradodecyl-ammoniumtetrakis(4-chlorophenyl) borate(ETH 500). This sensor shows very good selectivity and sensitivity towards cadmium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition, selectivity, pH and influence of additive on the response properties of electrode were investigated. The response mechanism was discussed in the view of UV-spectroscopy. The electrode exhibits a Nernstian behavior(with slope of 29.7 mV per decade) over a very wide concentration range from 1.0×10?1 to 1.0×10?8 mol·L?1 with a detection limit of 3.2×10?8 mol·L?1. It shows rela-tively fast response time in whole concentration range(<8 s) and can be used for at least 10 weeks in the pH range of 2.0-9.0. The proposed sensor is successfully used for the determination of cadmium in different chocolate sam-ples and as indicator electrode in titration with ethylene diamine tetraacetate(EDTA).
文摘Both calcium ionophore A23187 and endoplasmic reticulum Ca2+- ATPase inhibitor thapsigargin (Tg) could increase intracellular free calcium concentration and induce apoptosis in some cell lines. In the present study, we found that HL-60 cells treated with A23187 (1μg/ml) for 4 h or with Tg (0.5μg/ml) for 2 h showed typical characteristics of apoptosis. Pretreatment with nontoxic concentration of cyclosporin A (CsA) (1μg/ml) Could block these effects. Flow cytometric analysis of intracellular Ca2+ after staining with fluo-3 AM showed that CsA did not prevent the increase of intracellular calcium induced by A23187 or Tg, but it could maintain the high level of intracellular Ca2+ for a long time. These results suggest that CsA may prevent calcium- induced apoptosis by blocking the transportation of Ca2+ in HL-60cells.
文摘We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then the chlorine ion selective membrane is formed on the sensing window,and the fabrication of the EGFET chlorine ion sensing device is completed.The surface potential on the sensing membrane of the EGFET chlorine ion sensing device will be changed in the different chlorine ion concentration solutions,then changes further gate voltage and drain current to detect chlorine ion concentration.We will study non-ideal effects such as temperature,hysteresis and drift effects for the EGFET chlorine ion sensing device in this paper,these researches will help us to improve the sensing characteristics of the EGFET chlorine ion sensing device.
文摘A new chemically modified carbon paste electrode for cesium(I) ion determination based on potassium zinc hexacyan-oferrate (PZHCF) as an ionophore was prepared. The electrode exhibits a Nernstian response for Cs(I) ions over a wide concentration range from 1 × 10-6 to 1 × 10-1 mol·L-1 with a slope of 58 ± 0.5 mV·decade-1. It has a response time of about 35 s and can be used for a period of 3 months with good reproducibility. Detection limit obtained in the optimal conditions was 3 × 10-7 mol·L-1. The potentiometric response is independent of the pH of the solution in the pH range 4.0 - 8.0. The electrode possesses the advantages of low resistance, fast response over a variety of other cations. The proposed electrode is applied as a sensor for the determination of Cs(I) ion concentration in different samples solutions. The results showed a good correlation with the data obtained by atomic absorption spectrometric method.
基金supported by the Isfahan University of Technology(IUT),IR Iran(ARH) and grant GM 33138 (AER) from the national Institute of health,USA and center of Excellency in chemistry research(IUT).
文摘A novel calix[4]arene derivative 2 with amino functional groups at the lower rim was first prepared via introduction of nitro functional groups and amination of the dinitro derivative of calix[4]arene. The optically active monomers were synthesized by dehydration of L-leucine （and L-isoleucine） and 3,3＇,4,4＇-benzophenonetetracarboxylic- 3,3＇,4,4＇-dianhydride （3） followed by reaction with thionyl chloride to form 5a and 5b. Two methods, polymerization under microwave irradiation and solution polymerization in CH2Cl2/TEA, were then employed to carry out the condensation polymerization of 2 with the optically active monomers 5a and 5b, respectively. The polymerization conditions affected the kind of resulting polymers, poly（amide-imide）s （PAIs） 6a and 6b and poly（ester-imide）s （PEIs） 6a＇ and 6b＇ were obtained selectively in good yields and moderate inherent viscosities. Sorption-extraction experiments were carried out using cram picrate extraction method and verified good binding ability of the resulting calixarene-based polymers towards silver, alkali metal and toxic heavy metal cations. Also thermogravimetric analysis indicated that the resulting PAIs and PEIs were thermally stable.
文摘Three novel amprolium HCl（AMP）-selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride（PVC）. Sensor I was fabricated using potassium tetrakis（4-chlorophenyl） borate（Tp ClPB） as a cationic exchanger without incorporation of an ionophore.Sensor Ⅱ used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor Ⅲ used p-tert-butylcalix[8]arene as an ionophore. The three proposed sensors showed Nernestian response slopes of 29.2±0.8,29.3±0.6 and 30.2±0.4 m V/decade over the concentration range from 10–6 to 10–2 mol L_（-1）,respectively. The proposed sensors displayed useful analytical characteristics for the determination of AMP in bulk powder, different pharmaceutical formulations, and chicken liver and in the presence of ethopabate. The proposed method was validated according to ICH guidelines for its linearity, accuracy,precision and robustness.
基金This work was supported by the Natural Science Foundation of Hubei Province,China
文摘A modified method of preparing crown functionalized linear polysiloxane has been described. 4'-Allyldibenzo-18-crown-6 was subjected to hydrosilylation with methyldichlorosilane, followed by polycondensation with silanol-terminated polydimethylsiloxane to give the title crown functionalized linear polysiloxane. The transport properties of sodium, potassium, and ammonium salt through a bulk liquid membrane system using the new type of crown functionalized linear polysiloxane as a carrier were investigated. It is worthy to point out that the carrier can be used repeatedly at least six runs with no apparent change in the transport rate of potassium ion.
文摘Objective: To study the role of apoptosis in tumor cell of malignant glioma death following treatment with hyperthermia and calcium ionophore. Methods: The apoptosis induced by hyperthermia and calcium ionophore, A23187, in human glioblastoma cell line TJ905 and murine glioblastoma G422 was evaluated by characteristic findings in DNA agarose gel electrophresis, ultrastructural examination and flow cytometric analysis. Results: Apoptosis could be induced by moderate hyperthermia, but not by mild hyperthermia, calcium ionophore enhanced significantly the effect of mild hyperthermia on the induction of apoptosis. Conclusion: This result indicates that apoptotic cell death is one of the mechanisms of hyperthermic therapy for malignant glioma and taking measures to increase the cytolic calcium may enhance the effect of hyperthermia.
文摘Ionophores consist of molecules which surround and carry positive metal ions and other ions through biological membranes. One classe of ionophores which we have been developing contains dipeptides which are encouraged to become part of a ring because of possible hydrogen bond formation between the 2-hydroxy on the phenyl group and carboxyl group (COOH) of the final amide proline. Formation of a ring should increase the complexation ability of the ionophore. We report that the synthesis of N-(2-hydroxyl-1-phenoxyacetyl) prolyproline(1), a novel ionophore is prepared from activated 2-acetoxy phenoxyacetic acid (3a) and the appropriate dipeptide ester using coupling methods such as dicyclohexyl carbodiimide with hydroxyben-ztriazole or carbonyl diimidazole.
