硅凝胶联合超脉冲CO2点阵激光术对剖宫产术后皮肤瘢痕的预防及治疗效果

目的探讨硅凝胶联合超脉冲CO₂点阵激光术对剖宫产术后皮肤瘢痕的预防及治疗效果。方法前瞻性研究纳入2018年7~8月东莞市松山湖中心医院收治的100例剖宫产术后患者作为研究对象,分为观察组和对照组,各50例。对照组不予任何干预。观察组于手术伤口拆线后立即予硅凝胶涂抹,每日3次,3个月为1个疗程;观察组完成硅凝胶疗程后,有28例患者产生瘢痕,均立即采用超脉冲CO₂点阵激光术治疗,每3个月1次,共3次。2组患者于产后3、6、9、12及18个月时采用温哥华瘢痕评分量表(VSS)对瘢痕形态进行评分,采用视觉模拟评分法(VAS)对瘢痕疼痛及瘙痒情况进行评分。记录观察组的临床疗效和治疗过程中发生的不良反应。结果产后3、6、9、12及18个月,观察组VSS评分[(6.00±1.31)、(5.38±1.35)、(4.78±1.23)、(4.20±1.1)、(3.92±1.00)分]、疼痛[(2.84±1.02)、(2.40±0.93)、(2.06±0.62)、(1.20±0.67)、(1.04±0.60)分]及瘙痒[(3.00±1.05)、(2.50±0.86)、(2.12±0.67)、(1.34±0.59)、(1.12±0.59)分]评分均呈逐渐下降趋势,且明显低于同一时间段对照组VSS评分[(6.60±1.56)、(6.44±1.25)、(6.38±1.21)、(6.46±1.51)、(6.48±1.47)分]、疼痛[(3.94±0.87)、(3.82±0.83)、(3.76±0.72)、(3.72±0.81)、(3.66±0.87)分]及瘙痒[(4.08±0.99)、(3.98±0.89)、(4.00±0.90)、(4.04±0.92)、(3.96±0.95)分]评分,差异均有统计学意义(P<0.05);而对照组VSS评分、疼痛及瘙痒评分均未见明显变化(P>0.05)。观察组经超脉冲CO₂点阵激光术治疗后9个月(产后18个月),治疗的总有效率达92.9%,总显效率82.1%。观察组不良反应发生率低:轻度色素沉着14.29%,持续性红斑7.14%。结论硅凝胶联合超脉冲CO₂点阵激光术对剖宫产术后皮肤瘢痕的预防及治疗效果满意,不良反应轻微,值得临床推广应用。     

Toxicological implications of amplifying the antibacterial activity of gallic acid by immobilisation on silica particles: A study on C. elegans

Immobilisation of natural compounds on solid supports to amplify antimicrobial properties has reported successful results, but modifications to physico-chemical properties can also imply modifications from a toxicological viewpoint. This work aimed to study the immobilising process of gallic acid in the antibacterial activity of L. innocua and its toxicological properties in vivo using Caenorhabditis elegans. The experiment was based on obtaining the minimum bactericidal concentration for free and immobilised gallic acid by comparing lethality, locomotion behaviour, chemotaxis and thermal stress resistance on C.elegans at those concentrations. The results showed a lowering minimum bactericidal concentration and modifications to nematode responses. Increased lethality and velocity of movements was observed. Immobilisation increased the repellent effect of gallic acid with a negative chemotaxis index. Thermal stress resistance was also affected, with higher mortality for immobilised gallic acid compared to bare particles and free gallic acid. Thus despite evidencing a generalised increase in the toxicity of gallic acid in vivo, lowering the minimum bactericidal concentration allowed a bacterial reduction of 99 % with less than one third of mortality for the nematodes exposed to free gallic acid.     

Nanostructural control of the release of macromolecules from silica sol–gels

The therapeutic use of biological molecules such as growth factors and monoclonal antibodies is challenging in view of their limited half-life in vivo. This has elicited the interest in delivery materials that can protect these molecules until released over extended periods of time. Although previous studies have shown controlled release of biologically functional BMP-2 and TGF-β from silica sol–gels, more versatile release conditions are desirable. This study focuses on the relationship between room temperature processed silica sol–gel synthesis conditions and the nanopore size and size distribution of the sol–gels. Furthermore, the effect on release of large molecules with a size up to 70 kDa is determined. Dextran, a hydrophilic polysaccharide, was selected as a large model molecule at molecular sizes of 10, 40 and 70 kDa, as it enabled us to determine a size effect uniquely without possible confounding chemical effects arising from the various molecules used. Previously, acid catalysis was performed at a pH value of 1.8 below the isoelectric point of silica. Herein the silica synthesis was pursued using acid catalysis at either pH 1.8 or 3.05 first, followed by catalysis at higher values by adding base. This results in a mesoporous structure with an abundance of pores around 3.5 nm. The data show that all molecular sizes can be released in a controlled manner. The data also reveal a unique in vivo approach to enable release of large biological molecules: the use more labile sol–gel structures by acid catalyzing above the pH value of the isoelectric point of silica; upon immersion in a physiological fluid the pores expand to reach an average size of 3.5 nm, thereby facilitating molecular out-diffusion.     

硅胶假体隆鼻术并发症的分析及防治

目的：探讨固体硅胶假体对于隆鼻术并发症预防的心得体会,并提高手术质量。方法：笔者自2008年1月～2013年1月,选取应用硅胶假体隆鼻术456例。患者为首次手术或曾接受过单纯隆鼻术,术后形态不满意,要求再次手术。分析其中隆鼻术并发症的原因,对其进行针对性的治疗修复。结果：本组求美者接受手术治疗后均出现极大程度的外形改善,17例患者假体外露的部位为：鼻尖部11例,鼻翼缘内侧切口处6例。11例患者术后3天出现轻微歪斜,使用外部加压固定,2周后均恢复正常形态,7例感染。结论：根据求美者鼻部情况,选择恰当手术方案,掌握好适应证,正确操作是达到降低和预防隆鼻手术并发症的关键。     

二氧化硅提取核酸用于多聚酶链反应

利用硫氰酸胍裂解病毒和二氧化硅颗粒能够特异性吸附核酸的特性，将二氧化硅悬液、裂解液及肝炎病毒感染血清共同保温，病毒裂解释放出的核酸结合在二氧化硅颗粒上，经过双蒸水洗脱，所得核酸直接作ＰＣＲ扩增。     

硅胶胃管留置时间的研究

报道９０例重型颅脑损伤病人胃管留置时间的研究。随机将病人分为３组，置管时间甲组１１～２０天；乙组２１～３０天；丙组３１～４０天。结果：甲组与乙组对鼻、咽粘膜影响差异无显著性；乙组与丙组差异有显著性。结论：硅胶胃管留置适宜时间是２１～３０天。     

Oxidation of siloxanes during biogas combustion and nanotoxicity of Si-based particles released to the atmosphere

Siloxanes have been detected in the biogas produced at municipal solid waste landfills and wastewater treatment plants. When oxidized, siloxanes are converted to silicon oxides. The objectives of this study were to evaluate the transformation of siloxanes and potential nanotoxicity of Si-based particles released to the atmosphere from the gas engines which utilize biogas. Data available from nanotoxicity studies were used to assess the potential health risks associated with the inhalation exposure to Si-based nanoparticles. Silicon dioxide formed from siloxanes can range from 5 nm to about 100 nm in diameter depending on the combustion temperature and particle clustering characteristics. In general, silicon dioxide particles formed during from combustion process are typically 40–70 nm in diameter and can be described as fibrous dusts and as carcinogenic, mutagenic, astmagenic or reproductive toxic (CMAR) nanoparticles. Nanoparticles deposit in the upper respiratory system, conducting airways, and the alveoli. Size ranges between 5 and 50 nm show effective deposition in the alveoli where toxic effects are higher. In this study the quantities for the SiO₂ formed and release during combustion of biogas were estimated based on biogas utilization characteristics (gas compositions, temperature). The exposure to Si-based particles and potential effects in humans were analyzed in relation to their particle size, release rates and availability in the atmosphere. The analyses showed that about 54.5 and 73 kg/yr of SiO₂ can be released during combustion of biogas containing D4 and D5 at 14.1 mg/m³ (1 ppm) and 15.1 mg/m³ (1 ppm), respectively, per MW energy yield.     

Ligand-conjugated mesoporous silica nanorattles based on enzyme targeted prodrug delivery system for effective lung cancer therapy

Epidermal growth factor receptor antibody (EGFRAb) conjugated silica nanorattles (SNs) were synthesized and used to develop receptor mediated endocytosis for targeted drug delivery strategies for cancer therapy. The present study determined that the rate of internalization of silica nanorattles was found to be high in lung cancer cells when compared with the normal lung cells. EGFRAb can specifically bind to EGFR, a receptor that is highly expressed in lung cancer cells, but is expressed at low levels in other normal cells. Furthermore, in vitro studies clearly substantiated that the cPLA₂α activity, arachidonic acid release and cell proliferation were considerably reduced by pyrrolidine-2 loaded EGFRAb-SN in H460 cells. The cytotoxicity, cell cycle arrest and apoptosis were significantly induced by the treatment of pyrrolidine-2 loaded EGFRAb-SN when compared with free pyrrolidine-2 and pyrrolidine-2 loaded SNs in human non-small cell lung cancer cells. An in vivo toxicity assessment showed that silica nanorattles and EGFRAb-SN-pyrrolidine-2 exhibited low systemic toxicity in healthy Balb/c mice. The EGFRAb-SN-pyrrolidine-2 showed a much better antitumor activity (38%) with enhanced tumor inhibition rate than the pyrrolidine-2 on the non-small cell lung carcinoma subcutaneous model. Thus, the present findings validated the low toxicity and high therapeutic potentials of EGFRAb-SN-pyrrolidine-2, which may provide a convincing evidence of the silica nanorattles as new potential carriers for targeted drug delivery systems.     

New silica nanostructure for the improved delivery of topical antibiotics used in the treatment of staphylococcal cutaneous infections

In this paper, we report the synthesis, characterization (FT-IR, XRD, BET, HR-TEM) and bioevaluation of a novel γ-aminobutiric acid/silica (noted GABA-SiO₂ or γ-SiO₂) hybrid nanostructure, for the improved release of topical antibiotics, used in the treatment of Staphylococcus aureus infections. GABA-SiO₂ showed IR bands which were assigned to Si–O–Si (stretch mode). The XRD pattern showed a broad peak in the range of 18–30° (2θ), indicating an amorphous structure. Based on the BET analysis, estimations about surface area (438.14 m²/g) and pore diameters (4.76 nm) were done. TEM observation reveals that the prepared structure presented homogeneity and an average size of particles not exceeding 10 nm. The prepared nanostructure has significantly improved the anti-staphylococcal activity of bacitracin and kanamycin sulfate, as demonstrated by the drastic decrease of the minimal inhibitory concentration of the respective antibiotics loaded in the GABA-SiO₂ nanostructure. These results, correlated with the high biocompatibility of this porous structure, are highlighting the possibility of using this carrier for the local delivery of the antimicrobial substances in lower active doses, thus reducing their cytotoxicity and side-effects.