A new calcium silicate-based root canal dressing: physical and chemical properties, cytotoxicity and dentinal tubule penetration

Abstract The aims of this study were to evaluate the physical and chemical properties, cytotoxicity and dentinal tubule penetration of a new calcium silicate-based root canal dressing. For pH and calcium ion release evaluation (1, 24, 72 and 168 h) were used a pH meter and colorimetric spectrophotometer, respectively. Radiopacity evaluation followed the ISO 6876:2012. Cytotoxicity was evaluated by the percentage of cell viability using MTT assay. Illustrative images of dentinal tubule penetration were obtained using confocal laser scanning microscopy (CLSM). Data from pH and calcium ion release were statistically analyzed by two-way analysis of variance and Tukey test. Radiopacity was analyzed using the Student t-test. The statistical tests for cytotoxicity results were the one-way analysis of variance and Tukey test. Both materials showed alkaline pH in all experimental times. The pH values for calcium hydroxide paste were higher than bioceramic paste at 1, 24, and 72 h (p<0.05). The calcium ion release of bioceramic was lower than the calcium hydroxide paste only at 24 h (p<0.05). The bioceramic was more radiopaque than the calcium hydroxide paste (p<0.05). Bioceramic paste presented a dose and time-dependent cytotoxic effect after MTT assay. CLSM images showed absence of tubule penetration for both pastes. The new calcium silicate-based canal dressing presented alkaline pH, high calcium release, and acceptable radiopacity. Bio C Temp showed a dose and time-dependent cytotoxic and absence of dentinal tubule penetration.

Resumo Os objetivos deste estudo foram avaliar as propriedades físicas e químicas, citototoxidade e penetração tubular de uma nova medicação à base de silicato de cálcio. Para o teste de pH, e liberação de íons cálcio (1, 24, 72 e 168 h) foi usado medidor de pH e espectofotômetro colorimétrico, respectivamente. Avaliação da radiopacidade, seguiu a ISO 6876:2012). A citotoxicidade foi avaliada pela porcentagem de células viáveis usando o ensaio MTT. Imagens ilustrativas de penetração tubular foram obtidas usando microscopia confocal de varredura a laser (CLSM). Os dados de pH e liberação de cálcio foram analisados através do teste de Análise de Variância de duas vias e teste de Tukey. A radiopacidade foi avaliada usando o teste T de Student. Para a citotoxicidade foi empregada a Análise de Variância de uma via e teste de Tukey. Ambos os materiais apresentaram pH alcalino em todos os tempos experimentais. Os valores de pH da pasta de hidróxido de cálcio foram superiores à pasta biocerâmica em 1, 24 e 72 h (p<0,05). A liberação de cálcio da pasta biocerâmica foi inferior à pasta de hidróxido de cálcio apenas em 24 h (p<0,05). Bio-C Temp foi mais radiopaco que o Ultracal XS (p<0,05). A pasta biocerâmica apresentou efeito citotóxico dependente da dose e do tempo de exposição. Imagens de CLSM mostraram ausência de penetração intratubular para ambas as pastas. A nova medicação à base de silicato de cálcio apresentou pH alcalino, alta liberação de cálcio e boa radiopacidade. Bio C Temp apresentou um efeito citotóxico dependente da dose e do tempo de exposição e ausência de penetração tubular.

Acute application of ApoE4 increases the neuronal resting [Ca~(2+)] i in rat cortex / 基础医学与临床

Objective To investigate the acute effect of apolipoprotein E(apoE)on the intracellular free Ca~(2+) of rat cortical neurons. Methods The intracellular resting calcium level in cultured primary rat cortical neurons was measured by using confocal fluorescent imaging technique. MK-801, an N-methyl-D-aspartate (NMDA) receptor noncom-petitive antagonist, was employed to test potential function of apoE4 through blocking NMDN receptor. Results Acute application of apoE4, but not apoE3, significantly increased the resting [Ca~(2+)] i in a dose-and time-dependent manner (P <0. 01 or P <0. 05) , and MK-801 partly blocked the apoE4-induced elevation of resting [Ca~(2+)]i (P <0. 05 or P <0. 01). Conclusion Acute administration of ApoE4 disturbs calcium homeostasis, and the activation of NMDA receptor may play a critical role in the intracellular calcium overload induced by apoE4 and neurotoxicity.

Acute application of ApoE4 increases the neuronal resting[Ca~(2+)]i in rat cortex / 基础医学与临床

Objective To investigate the acute effect of apolipoprotein E(apoE)on the intracellular free Ca2+ of rat cortical neurons.Methods The intracellular resting calcium level in cultured primary rat cortical neurons was measured by using confocal fluorescent imaging technique. MK-801,an N-methyl-D-aspartate (NMDA) receptor noncompetitive antagonist,was employed to test potential function of apoE4 through blocking NMDN receptor. ResultsAcute application of apoE4,but not apoE3,significantly increased the resting [Ca2+]i in a dose-and time-dependent manner (P

Effects of bupivacaine on intracellular Ca~(2+) in rat ventricular myocytes / 中国临床药理学与治疗学

0.05).Intracellular Ca2+ FI in rat ventricular myocytes induced by KCl was inhibited significantly in group B2 and B3 compared with that in group C(P

Effects and mechanisms of compound G004 on experimental thrombosis / 中国临床药理学与治疗学

AIM:To study the effects and mechanisms of a novel sulfonylureous compound 1 ｛4 [2 (4 bromobenzenesulfonaminoethyl)phenylsufonyl｝ 3 (trans 4 methylcyclohexyl) urea, G004, on antithrombosis. METHODS: The influence of compound G004 on the vasoconstrictor action, platelet aggregation and thrombosis formation was studied. The effects of compound G004 on the tail vein bleeding time in mice was examined. The influence of compound G004 on the release of prostanglandin I 2 and thromboxan A 2 from ECV304 cells was investigated. The measurement of cytosolic free Ca 2+ in attached ECV304 cells loaded with Fluo3/AM was carried out. RESULTS: Compound G004 did not inhibit the contraction of rat aorta rings induced by norepinephrine or potassium chloride, but potently inhibit human platelet aggregation challenged by arachidonic acid and adenosine diphosphate. Compound G004 significantly prolonged the tail vein bleeding time in mice and occlusion time of carotid artery in experimentally thrombotic rats. Compound G004 reduced mice mortality induced by the collagen plus epinephrine in a dose dependent manner. Compound G004 enhanced PGI 2 release and reduced TXA 2 secretion from ECV304 cells. G004 had no effect on the increase of cytosolic free Ca 2+ induced by patassium chloride. CONCLUSION: The compound G004 has a remarkable antithrombotic effect in vivo. Its active mechanism may be attributed to inhibition of platelet aggregation, enhancing PGI 2 generation and decreasing TXA 2 secretion from human umbilical vein endothelium.

Effect of quateranary ammonium salt derivative (F_2) of haloperidol on calcium in vascular smooth muscle cells / 中国药理学通报

AIM To observe the effect of quateranary ammonium salt derivative (F 2) of haloperidol on calcium level in vascular smooth muscle cells (VSMCs) isolated from thoracic aortas of rat. METHODS VSMCs were loaded with Fluo 3 AM, a calcium sensitive fluorescent dye, and [Ca 2+ ] i was determined by the use of laser scanning confocal microscope (LCSM). RESULTS In Ca 2+ (1 26 mmol?L -1 ) bath solution, intracellular calcium fluorescent intensity (FI) in VSMCs was increased when application with 30 mmol?L -1 KCl, and then was inhibited after addition with F 2. The FI of the ASMCs with different concentrations of F 2 (0 1,1,10,100 ?mmol?L -1 )within three minutes were 64%?9%( n =16, P

Magnesium lithospermate B inhibits intracellular calcium elevation induced by ATP and KCl in rat vascular smooth muscle cells / 中国药理学通报

Aim To investigate the effects of magnesium lithospermate B(MLB) on vasoconstriction of denuded aortic rings in vitro,as well as the effects of MLB on cytosolic free calcium concentration([Ca~(2+)]_i) in aortic vascular smooth muscle cells(AVSMCs).Methods Isotonic tension was measured in the rat thoracic aortic rings without endothelium and quantitative changes of [Ca~(2+)]_i were directly monitored in AVSMCs loaded with the fluorescent calcium indicator Fluo-3 using intracellular cation measurement system.Results MLB had no effects on resting ring tension in the presence or absence of extracellular Ca~(2+).In rings exposed to 50～200 ?mol?L~(-1) MLB,the isotonic contractions induced by 1 ?mol?L~(-1) PE were decreased in calcium-free K-H solution.However,in the presence of extracellular Ca~(2+),KCl 60 mmol?L~(-1) produced isotonic contractions that were abolished by verapamil 10 ?mol?L~(-1) or inhibited by pretreatment of 50～200 ?mol?L~(-1) MLB in a concentration-dependent manner.When administered to the rings precontracted with 1 ?mol?L~(-1) PE in the absence of extracellular Ca~(2+),a second extracelluar-calcium-dependent vasoconstriction induced by restoration of extracellular Ca~(2+) was also reduced by pretreatment of 50～200 ?mol?L~(-1) MLB.Moreover,MLB,at concentration of 50～200 ?mol?L~(-1),produced little effect on AVSMCs [Ca~(2+)]_i in the presence or absence of extracellular Ca~(2+).In AVSMCs exposed to 50～200 ?mol?L~(-1) MLB,the inhibitory effects of MLB on [Ca~(2+)]_i induced by 20 ?mol?L~(-1) ATP were concentration-dependent,with decreases ranging from 17.4% to 61.1% in the absence of extracellular Ca~(2+).In the presence of extracellular Ca~(2+) and thapsigargin,the increases in AVSMCs [Ca~(2+)]_i evoked by 60 mmol?L~(-1) KCl were inhibited by pretreatment with MLB(50～200 ?mol?L~(-1)) or abolished by pretreatment with verapamil(10 ?mol?L~(-1)).Conclusions MLB inhibits vasoconstriction induced by PE,high-K~+,and re-Ca~(2+).MLB also has inhibitory effects on increase of [Ca~(2+)]_i induced by ATP and high K~+ in AVSMCs.These results indicate that both the blocking effects on calcium release and voltage-dependent calcium channels may be responsible for the effects of MLB on [Ca~(2+)]_i in vascular smooth muscle cells.

Mechanism of 5-hydroxytryptamine induced calcium signaling in cultured rat stomach fundus smooth muscle cells / 中国药理学通报

AIM To get an insight into intracellular signaling steps, a very early step in the signaling cascade, the biphasic Ca 2+ elicited by 5 HT in rat stomach fundus smooth muscle cells was investigated. METHODS Cells were cultured and loaded with Fluo 3 AM. [Ca 2+ ] i was measured by fluorescent intensity (FI) in each cell with confocal microscopy. RESULTS The resting FI level of SFSMC was 264?15. Stimulation of SFSMCs by 5 HT produced an elevation of [Ca 2+ ] i; Depletion of external Ca 2+ by addition of EGTA led to a significant attenuation of [Ca 2+ ] i change induced by 5 HT; Pre treatment of SFSMCs with ryanodine (10 ?mol?L -1 , 5 min) in D Hanks, the effect of 5 HT was completely inhibited; The stimulation of SFSMCs by 5 HT was partly attenuated by miaserin(10 ?mol?L -1 ), however, L type Ca 2+ channel antagonist lacidipine and G protein inhibitor NEM completely abolished the increase of [Ca 2+ ] i mediated by 5 HT; 5 HT mediated Ca 2+ release was reduced by phospholipase C specific inhibitor compound 48/80(1 2 ?g?ml -1 ); When protein kinase C was activated by phorbol 12 myristate 13 acetate (PMA 0 1 ?mol?L -1 , 5 min) the effect of 5 HT was inhibited, and the inhibitory effect of PMA was reversed by D sphingosine, a PKC inhibitor. CONCLUSION Our data suggest that G protein coupled 5 HT 2B receptor in the rat stomach fundus modulates 5 HT stimulated Ca 2+ increase, and it is coupled to calcium influx through L type calcium channels, and also intracellular calcium release by the opening of ryanodine receptor. The 5 HT 2B receptor mediated signal of 5 HT is transduced by PLC and PKC.