唇裂术后鼻畸形修复中硅胶假体的应用

目的 探讨硅胶假体在唇裂术后鼻畸形修复中的应用。方法 用常规方法矫正鼻畸形，使移位的鼻翼软骨、鼻中隔软骨复位，恢复正常的解剖关系，并于术中植入硅胶假体以达到更好的塑型。结果 行硅胶假体修复唇裂鼻畸形21例，无并发症发生，随访1～3年，外观满意。结论 在唇裂术后鼻畸形修复中应用硅胶假体可以获得更好的塑型。     

Refractive Change Caused Silicone Oil Adhesion to the Intraocular Lens Following Nd:YAG Posterior Capsulotomy

A 32-year-old female who had undergone the silicone oil removal procedure presented with visual disturbance in her left eye. Several months previous, she had cataract surgery in a private clinic, and a month later she had a Nd:YAG laser procedure for posterior capsulotomy. The slit-lamp examination revealed silicone oil droplets that had adhered to the intraocular lens where the posterior capsulotomy was performed. She had experienced high myopia as a manifestation of the resulting refractive changes. We replaced the previous intraocular lens with a new acrylic intraocular lens with resulting improvement to her vision. Here we report the case of a female patient with a history of silicone oil removal surgery where the resulting silicone bubbles had not been removed thoroughly and remained in the vitreous cavity. These bubbles subsequently adhered to the intraocular lens following YAG laser posterior capsulotomy, resulting in refractive changes. We recommend that implanting a silicone intraocular lens in anyone with a history of the silicone oil removal procedure or who has a possible history of silicone oil use should be avoided.     

Late results of silicone rubber perianal suture for rectal prolapse

Twenty-one patients were reviewed five to 12 years after silicone rubber perianal suture for rectal prolapse. Sixteen patients (76 percent) were continent with control of prolapse and two patients (9 percent) suffered only from occasional prolapse or incontinence. Rebanding for silicone cutout or fracture was required in four patients and a second rebanding operation was needed in two. Silicone rubber perianal suture for rectal proplapse stands the test of time and might be recommended for more widespread use in younger patients.     

Oranwash在间接法铸造桩核中的应用及护理

目的 探讨在间接法铸造桩核过程中应用硅胶印模材料Oranwash的护理要点。方法183例患者接受桩冠修复，使用Oranwash取根管印模及制备铸造桩核，根据各项操作步骤进行器械、材料准备及护理配合，并加以分析和讨论。结果 除2例出现桩脱住外，其余患者修复效果均满意。结论 在取模、制备铸造桩核过程中，护理配合的关键在于熟悉新材料特性和操作步骤。     

Description of a flow optimized oxygenator with integrated pulsatile pump

Extracorporeal membrane oxygenation (ECMO) is a well-established therapy for several lung and heart diseases in the field of neonatal and pediatric medicine (e.g., acute respiratory distress syndrome, congenital heart failure, cardiomyopathy). Current ECMO systems are typically composed of an oxygenator and a separate nonpulsatile blood pump. An oxygenator with an integrated pulsatile blood pump for small infant ECMO was developed, and this novel concept was tested regarding functionality and gas exchange rate. Pulsating silicone tubes (STs) were driven by air pressure and placed inside the cylindrical fiber bundle of an oxygenator to be used as a pump module. The findings of this study confirm that pumping blood with STs is a viable option for the future. The maximum gas exchange rate for oxygen is 48mL/min/L(blood) at a medium blood flow rate of about 300mL/min. Future design steps were identified to optimize the flow field through the fiber bundle to achieve a higher gas exchange rate. First, the packing density of the hollow-fiber bundle was lower than commercial oxygenators due to the manual manufacturing. By increasing this packing density, the gas exchange rate would increase accordingly. Second, distribution plates for a more uniform blood flow can be placed at the inlet and outlet of the oxygenator. Third, the hollow-fiber membranes can be individually placed to ensure equal distances between the surrounding hollow fibers.     

Alcohol enhanced permeation in model membranes. Part II. Thermodynamic analysis of membrane partitioning

The role of solvents in drug transport has not been properly addressed in the literature, despite its well known influence on drug permeation. Previously we have conducted thermodynamic and kinetic analyses to probe the molecular mechanisms of alcohol enhanced permeation. In the present study, the influence of temperature on the partitioning of methyl paraben into silicone membranes is investigated. In line with previous membrane transport studies of methyl paraben in silicone membranes, butanol and heptanol are used as representative alcohols. The results show higher amounts of methyl paraben extracted from the silicone membrane following equilibration with butanol, at all experimental temperatures. This was in line with alcohol uptake data. In fact, a linear correlation (r² ∼0.97) was found between the amount of methyl paraben in the silicone membrane and the corresponding alcohol uptake. Calculated “specific” vehicle-membrane partition coefficients for both alcohols were approximately one, suggesting that the effective concentrations of methyl paraben inside and outside the membrane were the same. Thermodynamic analysis of the alcohol-membrane partition coefficients as a function of temperature showed no apparent trend for butanol, with an associated enthalpy change of approximately zero. Conversely, there was a positive trend in the van’t Hoff plot for methyl paraben in heptanol, indicative of an exothermic process. Moreover, the partitioning trends of methyl paraben in silicone membranes obtained from membrane transport and equilibrium experiments were not the same. This reflects the fundamental differences between the calculated vehicle-membrane partition coefficients in the two studies. Finally, the findings from membrane transport and equilibrium experiments support a model of alcohol enhanced permeation where high solvent sorption promotes high solute concentrations in the overall volume of the membrane (i.e. K), thus leading to modified solute transport (i.e. increased flux). The same model also accounts for changes in membrane diffusivity (i.e. D) related to the properties of the imbibed alcohol.     

The influence of volatile solvents on transport across model membranes and human skin

Simple topical formulations which include volatile components, such as gels or sprays, are appealing from a cosmetic perspective. However, complex formulation effects may result from the use of volatile excipients in topical formulations, particularly when applied at clinically relevant doses (typically less than a few mg cm⁻²). The present investigation aims to study the role of the volatile solvent ethanol (EtOH), in combination with Transcutol P^® (TC), dimethyl isosorbide (DMI) and isopropyl myristate (IPM), on the efficacy of dermal delivery of a model compound (i.e. methyl paraben). The methodology consisted of in vitro diffusion experiments conducted using silicone membranes and human epidermis. Finite dose studies were performed with two types of formulations: saturated solutions of methyl paraben in each vehicle alone and incorporating the volatile solvent in a 50:50 (v/v) proportion. The kinetics of EtOH evaporation from the formulations were also investigated by monitoring the weight loss of the formulation over time. The results showed that the presence of EtOH had little effect on the skin flux of methyl paraben compared with the corresponding saturated solutions. Formulations incorporating the volatile solvent were clearly more efficient, in line with the data obtained with silicone membranes. Furthermore, the permeation of methyl paraben from the saturated EtOH solution in both silicone and skin showed an initial period of relatively fast permeation, after which there was a marked decrease in the permeation rate. This reflected significant ethanol depletion from the formulation (chiefly by evaporation), causing most of the dose of methyl paraben applied to crystallise as a deposited film at the skin surface (observed experimentally and confirmed by mass balance studies), thus decreasing its availability to permeate. Studies of the kinetics of ethanol evaporation from the formulations confirm these findings, demonstrating a very short residence time of the volatile solvent at the surface of the membrane (approx. 6 min). In conclusion, the findings suggest that rapid evaporation of EtOH takes place from the formulations applied at the surface of the skin, leaving a saturated residue of the drug in the vehicle. The presence of EtOH clearly influenced the efficiency of the formulation, underlining the application of volatile components to optimise dermal delivery.     

Long-Term Safety and Effectiveness of Style 410 Highly Cohesive Silicone Breast Implants

Background  In 2006, a single-center Swedish study demonstrated a low rupture rate and high patient satisfaction with the Style 410 shaped, form-stable gel implant. The current study aimed to validate the accuracy of the previously published results across multiple European sites. Methods  A total of 163 subjects (~70% had augmentation [n = 112], 15% had reconstruction [n = 25], and 15% had revision [n = 26]) underwent a physical examination followed by breast magnetic resonance imaging (MRI) for rupture detection. These subjects had been implanted for 5 to 11 years with at least one Style 410 shaped gel breast implant before examination. The secondary end points included lactation, reproductive and breast disease history before and after implantation, and quality-of-life measurements and complications after implantation. Results  The implant rupture rate was 1.7% a median of 8 years after implantation. Capsular contracture was the most common complication noted at the physical examination, occurring for 5.3% of implants, and there were no cases of grade 4 capsular contracture. The postimplantation rates for lactation and reproductive problems and breast disease were lower than the preimplantation rates. Breast implantation surgery was considered advantageous by 91% of the subjects, demonstrating high patient satisfaction. Conclusions  The Style 410 anatomically shaped, form-stable gel breast implants demonstrated long-term safety and effectiveness. Presented as a poster at the 19th Congress of the International Society of Aesthetic Plastic Surgery, Melbourne, Australia, 10–13 February 2008.     

Body Shaping and Volume Restoration: The Role of Hyaluronic Acid

Driven by the rising popularity of minimally invasive techniques, the demand for cosmetic procedures is increasing. Cosmetic body-shaping procedures can be categorized into those that remove tissue and those that add volume. This review focuses on the latter of these categories, particularly on the use of resorbable hyaluronic acid gels specifically developed for minimally invasive volume enhancement. Pilot studies of hyaluronic acid involving its injection to contour various body deformities and its recent use in female breast augmentation are discussed. Injectable hyaluronic acid is effective and well tolerated. It represents an attractive treatment option for volume restoration or augmentation by providing predictable long-lasting results after minimally invasive administration. Alternative treatment options for volume enhancement also are summarized including fat transfer, silicone implants, and the use of injectable nonresorbable products such as silicone, polyalkylimide, and polyacrylamide gels. As patients continue to opt for nonsurgical procedures that offer predictable results, the development of minimally invasive products such as hyaluronic acid is increasingly important.     

Superior in vitro biological response and mechanical properties of an implantable nanostructured biomaterial: Nanohydroxyapatite–silicone rubber composite

A potential approach to achieving the objective of favorably modulating the biological response of implantable biopolymers combined with good mechanical properties is to consider compounding the biopolymer with a bioactive nanocrystalline ceramic biomimetic material with high surface area. The processing of silicone rubber (SR)–nanohydroxyapatite (nHA) composite involved uniform dispersion of nHA via shear mixing and ultrasonication, followed by compounding at sub-ambient temperature, and high-pressure solidification when the final curing reaction occurs. The high-pressure solidification approach enabled the elastomer to retain the high elongation of SR even in the presence of the reinforcement material, nHA. The biological response of the nanostructured composite in terms of initial cell attachment, cell viability and proliferation was consistently greater on SR–5 wt.% nHA composite surface compared to pure SR. Furthermore, in the nanocomposite, cell spreading, morphology and density were distinctly different from that of pure SR. Pre-osteoblasts grown on SR–nHA were well spread, flat, large in size with a rough cell surface, and appeared as a group. In contrast, these features were less pronounced in SR (e.g. smooth cell surface, not well spread). Interestingly, an immunofluorescence study illustrated distinct fibronectin expression level, and stronger vinculin focal adhesion contacts associated with abundant actin stress fibers in pre-osteoblasts grown on the nanocomposite compared to SR, implying enhanced cell–substrate interaction. This finding was consistent with the total protein content and SDS–PAGE analysis. The study leads us to believe that further increase in nHA content in the SR matrix beyond 5 wt.% will encourage even greater cellular response. The integration of cellular and molecular biology with materials science and engineering described herein provides a direction for the development of a new generation of nanostructured materials.