The role of potassium channel in silica nanoparticle-induced inflammatory effect in human vascular endothelial cells in vitro

Exposure to nanoparticles became popular in industry and daily life. Nano-SiO₂ was shown to have an adverse effect to vascular endothelial cell although the mechanisms remain unclear. To test whether the nano-SiO₂'s harmful effect was related to the potassium channel, human umbilical vascular endothelial cells (HUVECs) were treated with nano-SiO₂ in different dose. Cell survival rate and lactate dehydrogenase (LDH) as cytotoxic parameters, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) as inflammation indicators were determined. The electrophysiological changes and function of potassium channel were detected with patch clamp and channel blockers. It was found that nano-SiO₂ exposure decreased cell survival rate, increased LDH leakage, TNF-α and IL-6 production. The potassium channel activity was increased in the opening rate and current intensity. Furthermore, potassium channel blockers tetraethylammonium (TEA), 4-amino pyridine (4-AP), and margatoxin (MGTX) reduced the nano-SiO₂-induced cytotoxity and inflammation, i.e., increase in the cell survival rate, and decrease in the LDH leakage and production of TNF-α and IL-6. It might be concluded that the nano-SiO₂-induced inflammation and cytotoxicity at HUVECs was associated with the activation of potassium channel.     

In Vitro Release of Cisplatin from Sol-Gel Processed Porous Silica Xerogels

Cisplatin an antineoplastic medicine, was incorporated into a silica gel received by the sol-gel method. Various techniques of trapping an active substance in gel were applied: at the stage of sol creation—by the predoping method—and already upon receipt of hard xerogel—the postdoping method. Further, the research aimed at the determination of the dynamics of cisplatin release from sol-gel processed silica xerogel to the water phase. Based on the achieved results, we may state that the sol-gel method is useful for trapping a medicine like cisplatin in silica gel and gives repeatable results with regard to medicine release from the pores of the so-established matrix. The postdoping method appeared to be more beneficial, because the gained gel's active substance is released almost entirely (94–96%). The time of release was 3 days.     

硅胶假体联合脱细胞异体真皮垫在低鼻尖隆鼻术中的应用

目的探讨硅胶假体联合脱细胞异体真皮垫在低鼻尖隆鼻术中的应用效果。方法对82例低鼻尖隆鼻术患者,在进行硅胶假体隆鼻时,将脱细胞异体真皮垫缝于假体鼻头部的顶端,然后置于鼻假体腔隙内,利用硅胶假体的厚度及真皮垫的作用,将鼻尖顶起,从而达到抬高鼻尖的目的。结果本组患者术后随访6个月至2年,鼻尖部位均得到较大的抬高,低鼻尖得到矫正,效果满意。结论假体联合脱细胞异体真皮垫,在低鼻尖隆鼻术中应用效果良好,值得临床推广。     

La biopsia cutánea en el contexto de la enfermedad sistémica

The skin is the largest and most exposed organ in the human body and the ideal place to look for signs that aid in the early diagnosis of systemic diseases with cutaneous effects. As the concepts that underpin our understanding of many of these diseases have evolved or expanded in recent years, there have also been changes in the criteria we use for early diagnosis, including our approaches to skin biopsy and dermatopathologic evaluation. This review focuses on some of the systemic processes with skin manifestations for which our basic understanding has changed most in recent decades.     

Radiopaque dental adhesives: dispersion of flame-made Ta2O5/SiO2 nanoparticles in methacrylic matrices

OBJECTIVES: Radiopaque dental adhesive (DA) of low viscosity were made by forming stable suspensions of weakly agglomerated Ta2O5/SiO2 nanoparticles with primary particle size of about 10nm. METHODS: The particles were prepared by one-step flame-spray pyrolysis. Particles were functionalized with gamma-methacryloxypropyltrimethoxysilane (MPS) and dispersed in a methacrylic monomer matrix by centrifugal mixing and ultrasonication. Particle size distributions were analyzed by X-ray disc centrifugation of suspensions and TEM analysis of cured sample composites, while average primary particle size was obtained by N2 adsorption and X-ray diffraction. RESULTS: The dispersion method affected the aggregate size distribution of both untreated and surface functionalized particles in these suspensions. The influence of particle content on suspension viscosity, aggregate size distribution and that of Ta2O5 content on radiopacity was investigated. The shear bond strength of such radiopaque particle-containing adhesives on enamel and dentin was comparable to that of the particle-free reference adhesive. CONCLUSIONS: Flame-made Ta2O5/SiO2 nanoparticles can be introduced readily into dental adhesives as they form quite stable suspensions. Viscosity stayed low even after adding radiopaque particles up to 20 wt.%. The resulting composites had radiopacity comparable to that of enamel facilitating their distinction from marginal gaps. Bond strength was not significantly influenced by the presence of particles in the adhesive.     

An erythropoietic stimulating factor similar to erythropoietin released by macrophages after treatment with silica

Summary An erythropoietic stimulating factor (ESF) can be detected in the supernatant from fetal liver and adult bone marrow and spleen cells when preincubated with the macrophage-specific cytotoxic agent, silica. Stimulation is observed in 12-day fetal liver CFU-E cultures in the absence of added erythropoietin (Ep). The concentration of ESF in the supernatant added to CFU-E cultures is dependent on the preincubated cell dose and the volume added. The stimulating activity is abolished when mice are hypertransfused and increased above normal values when mice are bled. A concentrated silicatreated spleen supernatant was able to stimulate erythropoiesis in the polycythemic mouse bioassay. It is concluded that the ESF is similar, if not identical, to Ep.This work was supported by the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich 112/Project A2) and the Volkswagen Foundation.     

硅涂层溶胶-凝胶法制备过程中碳酸氢钠促凝对氧化锆陶瓷粘接强度的影响

目的 探讨硅涂层溶胶-凝胶法制备过程中碳酸氢钠(NaHCO3)促凝对氧化锆陶瓷粘接强度的影响,为溶胶-凝胶法制备硅涂层的临床应用提供实验依据.方法 对比掺杂质量分数为1％、3％、5％、7％、10％的NaHCO3后氧化硅溶胶的胶凝时间,选取胶凝时间最短者进行后续实验.制作5组氧化锆-复合树脂粘接试件,A组:氧化铝喷砂;B组:氧化铝喷砂+摩擦化学法制备硅涂层+硅烷化;C组:氧化铝喷砂+溶胶-凝胶法制备硅涂层+硅烷化;D组:氧化铝喷砂+溶胶-凝胶法制备硅涂层过程中使用NaHCO3促凝+硅烷化;E组:氧化铝喷砂+氧化锆涂底剂处理.测试5组试件抗剪切强度,即粘接强度.结果 掺杂10％的NaHCO3后氧化硅溶胶的胶凝时间最短.B、C、D、E组粘接强度[分别为(10.24±2.78)、(7.36±1.59)、(9.79±2.07)、(8.39 ±0.49) MPa]均比A组[(4.12±0.52) MPa]显著提高,C和D组间差异无统计学意义(P＞0.01).结论 掺杂NaHCO3后氧化硅溶胶的胶凝时间缩短,涂层制备过程中使用NaHCO3促凝不影响氧化锆陶瓷的粘接强度.     

Liver functions in silica-exposed workers in Egypt: possible role of matrix remodeling and immunological factors

Background:

Brick manufacturing constitutes an important industrial sector in Egypt with considerable exposure to silica.

Objectives:

We aimed for evaluating hepatic functions in silica-exposed workers in the clay brick industry, and the possible role of matrix remodeling and immunological factors.

Methods:

A case–control study, 87 workers as exposed and 45 as control subjects. Questionnaire, clinical examination, and laboratory investigations: liver functions, matrix metalloproteinase-9, immunoglobulins G and E, and anti-liver kidney microsomal antibody.

Results:

In the exposed workers, mean levels of liver functions, matrix metalloproteinase-9 (MMP-9), and IgG and IgE were significantly higher. In the silicotic subgroup the mean level of GGT was almost twice the level in the non-silicotic subjects. Logistic regression showed that abnormal GGT and ALT were associated with production workers.

Conclusion:

Workers in the clay brick industry showed evidence of liver disease that could be related to matrix remodeling.     

溶胶-凝胶法制备硅涂层提高牙科高强度陶瓷与复合树脂的粘接强度

目的:探讨溶胶-凝胶法在牙科高强度陶瓷表面改性对陶瓷和复合树脂粘接强度的影响。方法:喷砂玻璃氧化铝陶瓷和氧化锆陶瓷片各72片,每种陶瓷随机分为4组,每组18片,采取以下处理:A组,硅烷偶联剂;B组,20%硅溶胶涂层+硅烷偶联剂;C组,30%硅溶胶涂层+硅烷偶联剂;(D)40%硅溶胶涂层+硅烷偶联剂,制作陶瓷-复合树脂粘接体;每组样本再分为2个亚组,分别在37℃水浴中放置24 h和30 d后,测定陶瓷和树脂的剪切粘接强度。结果:2种陶瓷水浴24 h后,各涂层组粘接强度与单纯硅烷偶联剂组相比差异有统计学意义,其中30%硅溶胶处理组的粘接强度最高(P<0.05)。水浴30 d后,各组粘接强度均和水浴初期(24 h)相比差异无统计学意义,30%硅溶胶处理组的粘接强度最高(P<0.05)。结论:牙科氧化铝陶瓷和氧化锆陶瓷经过溶胶凝胶法纳米硅涂层表面改性结合硅烷偶联剂的处理可以显著提高陶瓷和树脂的粘接强度,并保持较好的粘接耐久性,30%硅溶胶提高粘接强度的效果最好。