Solubility and apical sealing characteristics of a new calcium silicate-based root canal sealer in comparison to calcium hydroxide-, methacrylate resin- and epoxy resin-based sealers

Abstract

Aim. To assess and compare the water sorption, solubility and apical sealing ability of iRoot SP and three other widely used root canal sealers. Materials and methods. Solubility was assessed by immersing standardized samples of calcium silicate- (iRoot SP), calcium hydroxide- (Sealapex), methacrylate resin- (EndoREZ) and epoxy resin- (AH Plus) based sealers in distilled water and measuring weight gain and weight loss at 6 h, 24 h and daily for 14 days. Roots of extracted mandibular premolars (n = 80) were prepared with 0.04-taper nickel-titanium rotary files to a final size 40. Roots were then randomly divided into four experimental groups (n = 18) and two control groups (n = 4), root canal sealers were applied and apical leakage was assessed using the fluid filtration method. Data was analyzed using Kruskal Wallis analysis of variance and Mann-Whitney U-tests, with the level of significance set at p ≤ 0.05. Results. EndoREZ exhibited the highest water sorption, followed by iRoot SP, Sealapex and AH Plus. Sealapex exhibited significantly higher solubility than the other sealers, whereas no significant differences in solubility levels were observed between the other three sealers tested. AH Plus exhibited significantly lower microleakage than Sealapex and EndoREZ, whereas no difference in microleakage was found between AH Plus and iRoot SP. Conclusions. In view of the study findings, all tested sealers except Sealapex met the ANSI/ADA's requirements for solubility and no difference was found between AH Plus and iRoot SP in terms of apical sealing ability.     

鞘内注射JNK特异性抑制剂SP600125对CCI大鼠痛行为的影响

Objective To observe the effect of intrathecal administration of SP600125 on both MWT and TWL of rats after chronic constriction injury (CCI) of the sciatic nerve. Methods 40 male SD rats were randomized to deride into 5 groups (n=8). Rats in group SP5 received SP600125 5 μg after CCI; rats in group SP25 received SP600125 25 μg after CCI; rats in group SP50 received SP600125 50 μg after CCI; rats in group DMSO received 2% DMSO 10 μl after CCI; rats in group Naive received SP600125 50 μg without sciatic nerve injury. SP600125 was dissolved in 10 μl 2%DMSO solvent. On the 7th day after CCI, MWT and TWL were determined with yon Frey filaments and thermal radiation apparatus repectively after intrathecal administration of SP600125. Results Intrathecal administration certain dosage of SP600125 could attenuate the established mechanical allodynia and thermal hyperalgesia induced by CCI rather than normal rats. Conclusion Intrathecal administration certain dosage of SP600125 could attenuate the established mechanical allodynia and thermal hyperalgesia induced by CCI.     

鞘内注射JNK特异性抑制剂SP600125对CCI大鼠痛行为的影响

Objective To observe the effect of intrathecal administration of SP600125 on both MWT and TWL of rats after chronic constriction injury (CCI) of the sciatic nerve. Methods 40 male SD rats were randomized to deride into 5 groups (n=8). Rats in group SP5 received SP600125 5 μg after CCI; rats in group SP25 received SP600125 25 μg after CCI; rats in group SP50 received SP600125 50 μg after CCI; rats in group DMSO received 2% DMSO 10 μl after CCI; rats in group Naive received SP600125 50 μg without sciatic nerve injury. SP600125 was dissolved in 10 μl 2%DMSO solvent. On the 7th day after CCI, MWT and TWL were determined with yon Frey filaments and thermal radiation apparatus repectively after intrathecal administration of SP600125. Results Intrathecal administration certain dosage of SP600125 could attenuate the established mechanical allodynia and thermal hyperalgesia induced by CCI rather than normal rats. Conclusion Intrathecal administration certain dosage of SP600125 could attenuate the established mechanical allodynia and thermal hyperalgesia induced by CCI.     

Plasma levels of SP1-like immunoreactive material (SP1) and progesterone throughout pregnancy and following RU 486-induced early abortion in the cynomolgus monkey (Macaca fascicularis)

A human-SP1 immunoassay was used to detect SP1-like material (SP1) in the plasma of cynomolgus monkeys. In 27 females remaining non-pregnant during a mating period of 4 months, SP1 was occasionally detected at a mean concentration of 2.5 ng/ml. In 14 non-pregnant females of subsequent proven fertility, SP1 was detected 20 days following unfertile mating at a mean concentration of 4.8 ng/ml in 86% of cycles. At day 20 of proven pregnancies, SP1 was at 12 ng/ml in 93% of these animals. SP1 levels during pregnancy increased in two steps, a slow rise between days 20 and 50, followed by an abrupt rise between days 50 and 60 and afterwards a plateau at 600 ng/ml. Seven other pregnant monkeys received 10 mg/kg of the antiprogestin RU 486 at 28 days. Four aborted and the others continued their gestation. SP1 was always dramatically depressed by this treatment; in animals with abortion failure, it remained at a low concentration for 3 months, then the normal concentration range was recovered. The assay of SP1-like material does not allow early diagnosis of pregnancy, however, it remains interesting as a follow-up parameter after 60 days. Also, antiprogestins appear to be useful tools to analyse the metabolism of SP1.     

高强度聚焦超声与无水乙醇毁损腰交感神经节对犬后肢动脉闭塞病变影响的比较研究

目的：用无水乙醇和高强度聚焦超声（HIFU）阻滞后肢动脉闭塞犬腰交感神经节，比较两种处理方式对后肢皮肤温度、神经节形态结构及脊髓P物质影响的差异。方法：27只杂种犬制作后肢缺血模型，术后2周随机分为3组（各组n=9）：对照组（A组），HIFU治疗组（B组），乙醇治疗组（C组）。A组不予处理，B组和C组分别用HIFU和无水乙醇阻滞腰交感神经节。各组在造模前、治疗前（造模后2周）、治疗后1周分别检测肢体皮肤温度、神经节形态结构及脊髓P物质含量的变化。结果：（1）三组造模后与造模前相比皮肤温度均显著降低（P〈0．05），治疗后B、C两组回升。（2）镜下B组所有神经元细胞出现坏死；C组大部分神经元坏死。（3）SP免疫阳性反应物集中分布在脊髓背角Ⅰ、Ⅱ层，造模后各组脊髓腰段SP的平均光密度（OD）值与造模前相比均显著升高（P〈0．01），治疗后B、C两组脊髓腰段SP的OD值较治疗前显著降低（P〈0．05），组间无显著差异（P〉0．05），结论：高强度聚焦超声和无水乙醇均可有效阻滞腰交感神经节，两种方法在对后肢动脉闭塞犬后肢皮肤温度、脊髓P物质改变方面影响无显著差异，而HIFU对神经节破坏更彻底。     

bcr-abl基因疫苗对小鼠SP2/0/bcr-abl移植瘤的影响

为了研究bcr—abl融合基因疫苗对小鼠SP2／0／bcr—abl移植瘤的影响，采用pVbcr—abl、pVbcr—abl／mIL7两种质粒分别免疫BALB／c小鼠，然后用SP2／0／bcr—abl细胞攻击免疫小鼠，观察疫苗对SP2／0／bcr—abl移植瘤生长的影响，检验其是否具有免疫保护作用。结果表明：用基因疫苗免疫的两个实验组与两个对照组（空白对照组和空载体对照组）相比，在移植肿瘤形成时间、肿瘤表面破溃时间、肿瘤体积、荷瘤生存期等指标上均存在明显差异。pVbcr—abl／mIL7免疫小鼠组的荷瘤生存时间比pVbcr—abl免疫组相对延长。常规病理学分析发现，对照组小鼠的移植瘤组织比较致密，瘤细胞体积较大，形状不规则，而两个免疫组的肿瘤组织较为疏松，肿瘤细胞体积相对较小，并有大量炎性细胞浸润。两个对照组小鼠的肝脏组织内发现有大量肿瘤转移灶，而两个免疫组小鼠则未发现。结论：接受bcr—abl基因疫苗免疫的小鼠被诱导产生较强的特异性免疫保护力，对SP2／0／bcr—abl移植瘤的体内生长有一定抑制能力。     

Effects of movement imitation training in Parkinson's disease: A virtual reality pilot study

BackgroundHypometria is a clinical motor sign in Parkinson's disease. Its origin likely emerges from basal ganglia dysfunction, leading to an impaired control of inhibitory intracortical motor circuits. Some neurorehabilitation approaches include movement imitation training; besides the effects of motor practice, there might be a benefit due to observation and imitation of un-altered movement patterns. In this sense, virtual reality facilitates the process by customizing motor-patterns to be observed and imitated.ObjectiveTo evaluate the effect of a motor-imitation therapy focused on hypometria in Parkinson's disease using virtual reality.MethodsWe carried out a randomized controlled pilot-study. Sixteen patients were randomly assigned in experimental and control groups. Groups underwent 4-weeks of training based on finger-tapping with the dominant hand, in which imitation was the differential factor (only the experimental group imitated). We evaluated self-paced movement features and cortico-spinal excitability (recruitment curves and silent periods in both hemispheres) before, immediately after, and two weeks after the training period.ResultsMovement amplitude increased significantly after the therapy in the experimental group for the trained and un-trained hands. Motor thresholds and silent periods evaluated with transcranial magnetic stimulation were differently modified by training in the two groups; although the changes in the input–output recruitment were similar.ConclusionsThis pilot study suggests that movement imitation therapy enhances the effect of motor practice in patients with Parkinson's disease; imitation-training might be helpful for reducing hypometria in these patients. These results must be clarified in future larger trials.     

C-Jun氨基末端激酶信号通路在急性一氧化碳中毒迟发性脑病中的作用

目的探讨c-Jun氨基末端激酶(c-Jun N-terminal kinas,JNK)信号通路在急性一氧化碳中毒迟发性脑病中的作用。方法 120只雄性SD大鼠随机分成空白对照组(BC组)、急性一氧化碳中毒迟发性脑病组(CO组)和JNK抑制剂SP600125组(SP组)3组,每组40只,采用静态吸入式染毒法复制急性一氧化碳中毒迟发性脑病大鼠模型,选取染毒后1、3、7、14、28 d为时相点,应用Morris水迷宫试验检测平均潜伏期等学习记忆能力,免疫组化法检测海马区p-JNK表达,Tunel法检测海马区锥体细胞凋亡。结果 CO组大鼠平均潜伏期较BC组明显延长(P0.01),SP组较CO组明显缩短(P0.01),但仍比BC组延长(P0.01);p-JNK在CO组大鼠海马区表达较BC组明显增强(P0.01),SP组较CO组表达明显减弱(P0.01),较BC组明显增强(P0.01);CO组海马区锥体细胞第3天已经有凋亡增多(9.94%±1.22%),第7和14天增多最明显(39.77%±1.91%,29.72%±4.89%),第28天仍然增多(5.88%±0.55%),凋亡指数与BC组相比有明显增高(P0.01),而SP组凋亡指数与CO组相比明显降低(P0.01)。结论 JNK信号通路参与了急性一氧化碳中毒迟发性脑病的发生,应用其特异性抑制剂SP600125阻断其转导可减少海马区神经元的凋亡,减轻急性CO中毒对学习记忆能力的损害。