Resection and augmentation of Bichat's fat pad in facial contouring

Summary The Bichat's fat pad (Corpus adiposum buccae) is of great significance in facial contouring. Resection of major parts of this fat pad results in hollow cheeks and in accentuation of the zygoma. On the other hand, hypoplasia or shrinkage of this fat pad can be augmented by means of silicone implants for improved aesthetic results.     

Reconstruction of pectus excavatum with silicone implants.

The pectus excavatum deformity is characterised by a deep depression usually involving the lower one-half to two-thirds of the sternum. The indications for surgery are often aesthetic. Extensive procedures, requiring fracturing and remodelling of the chest wall skeleton are associated with high morbidity and high rate of complications. In this article we describe our renewed experience with reconstruction of mild and moderate pectus excavatum deformities with custom made prefabricated silicone implants. The fabrication of the implant and the surgical technique are described in detail. An excellent aesthetic correction of the deformity was achieved in all of the patients in our series, with high patient satisfaction rate. We conclude that with careful patient selection, artistic implant fabrication and meticulous surgical technique, this approach achieves excellent aesthetic correction with minimal morbidity and a low complication rate and therefore should maintain its place in the armamentarium of surgical techniques for reconstruction of pectus deformities.     

硅胶薄膜囊预防椎体后凸成形术中骨水泥渗漏的实验研究

目的探讨硅胶薄膜囊预防椎体后凸成形术中骨水泥渗漏的可能性和有效性。方法取6具甲醛固定的老年女性脊柱标本(T12～L5)制成36个单椎体,刮匙在椎体前3/4制成体积约为6ml单侧或双侧空腔,分别直接注入骨水泥和先置入壁厚100μm、200μm的硅胶薄膜囊后再注入骨水泥。结果壁厚100μm的硅胶薄膜囊包裹骨水泥可控制骨水泥在椎体内的分布,和直接注入骨水泥一样能较好地嵌入到周围骨小梁内,不形成界面。而壁厚200μm的硅胶囊虽能控制骨水泥在椎体内分布,但会在骨小梁间形成界面。结论球囊扩张椎体后凸成形术中置入壁厚100μm的硅胶薄膜囊包裹骨水泥可控制椎体内骨水泥分布,并能嵌入到骨小梁间隙,不形成界面,有效预防球囊扩张椎体后凸成形术并发症的出现。     

Engineering angiogenesis following spinal cord injury: a coculture of neural progenitor and endothelial cells in a degradable polymer implant leads to an increase in vessel density and formation of the blood–spinal cord barrier

Angiogenesis precedes recovery following spinal cord injury and its extent correlates with neural regeneration, suggesting that angiogenesis may play a role in repair. An important precondition for studying the role of angiogenesis is the ability to induce it in a controlled manner. Previously, we showed that a coculture of endothelial cells (ECs) and neural progenitor cells (NPCs) promoted the formation of stable tubes in vitro and stable, functional vascular networks in vivo in a subcutaneous model. We sought to test whether a similar coculture would lead to the formation of stable functional vessels in the spinal cord following injury. We created microvascular networks in a biodegradable two-component implant system and tested the ability of the coculture or controls (lesion control, implant alone, implant + ECs or implant + NPCs) to promote angiogenesis in a rat hemisection model of spinal cord injury. The coculture implant led to a fourfold increase in functional vessels compared with the lesion control, implant alone or implant + NPCs groups and a twofold increase in functional vessels over the implant + ECs group. Furthermore, half of the vessels in the coculture implant exhibited positive staining for the endothelial barrier antigen, a marker for the formation of the blood–spinal cord barrier. No other groups have shown positive staining for the blood–spinal cord barrier in the injury epicenter. This work provides a novel method to induce angiogenesis following spinal cord injury and a foundation for studying its role in repair.     

隆乳术后27例取除假体者原因分析

通过对隆乳术后27例取除假体者的原因进行分析,进一步揭示了目前隆乳术中仍存在的某些不足,发现术后感染、疼痛、假体破裂或外露、包膜挛缩、病人心态失衡等都是造成假体取出的直接原因。认为采取高质量的假体胸大肌下间隙隆乳是降低并发症提高隆乳术质量的关键。     

Control of Mammalian Cell and Bacteria Adhesion on Substrates Micropatterned with Poly(ethylene glycol) Hydrogels

A simple method for controlling the spatial positioning of mammalian cells and bacteria on substrates using patterned poly(ethylene glycol) (PEG) hydrogel microstructures is described. These microstructures were fabricated using photolithography on silicon, glass or poly (dimethylsiloxane) (PDMS) surfaces modified with a 3-(trichlorosilyl) propyl methacrylate (TPM) monolayer. During the photogelation reaction, the resulting hydrogel microstructures were covalently bound to the substrate via the TPM monolayer and did not detached from the substrate upon hydration. For mammalian cell patterning, microwell arrays of different dimensions were fabricated. These microwells were composed of hydrophilic PEG hydrogel walls surrounding hydrophobic TPM floors inside the microwells. Murine 3T3 fibroblasts and transformed hepatocytes were shown to selectively adhere to the TPM monolayer inside the microwells, maintaining their viability, while adherent cells were not present on the hydrogel walls. The number of cells inside one microwell could be controled by changing the lateral dimension of the microwells, thus allowing only a single cell per microwell if desired. In the case of 30×30 m microwells, as many as 400 microwells were fabricated in 1 mm². In addition, PEG hydrogel microstructures were also shown to effectively resist the adhesion of bacteria such as Escherichia coli.     

Poly(ethylene glycol)-containing Hydrogels for Oral Protein Delivery Applications

Novel pH-sensitive hydrogels were developed as suitable candidates for carriers in bioMEMS devices as well as for oral delivery of therapeutic peptides and proteins due to their ability to respond to environmental pH change. Macromonomers containing various PEG molecular weights were synthesized and used to prepare P(MAA-g-EG) hydrogels were by photopolymerization. P(MAA-g-EG) hydrogels showed a drastic change of the equilibrium swelling ratio between pH 2.2 and 7.0. At pH 7.0, hydrogels with PEGMA2000 exhibited higher swelling ratio than hydrogels with PEGMA1000. For both hydrogels with PEGMA1000 and PEGMA2000, the swelling mechanism became more relaxation-controled as the environmental pH changed from 2.2 to 7.0 due to the ionization of the functional groups in polymer networks at high pH. In vitro release studies of insulin were conducted. P(MAA-g-EG) hydrogels exhibited drastic increase of insulin release as the pH of the medium was changed from acidic to basic. Insulin release from P(MAA-g-EG) hydrogels with PEGMA2000 was slower than from hydrogels with PEGMA1000 at both low and high pH. These results were used to design and improve protein release behavior from these carriers.     

Hydrogels in endovascular embolization. II. Clinical use of spherical particles

In this study we report the results of clinical experiments, obtained with spherical particles made from poly(2-hydroxyethyl methacrylate) used in the embolization of arteriovenous anastomoses, in the suppression of pulmonary haemorrhage and haemoptysis and in the occlusion of some other arteries. So far we have used these particles in the treatment of 187 patients. It must be stressed that the advantage of spherical particles consists in the simplicity of their introduction into the blood vessel through a catheter, while in the blood vessel itself the particle swells in blood still more, when compared with the particle size in saline. This results in an immediate and permanent haemostatic effect. No revascularization occurs.     

Chitosan hydrogel as a drug delivery carrier to control angiogenesis

An aqueous solution of photocrosslinkable chitosan containing azide groups and lactose moieties (Az-CH-LA) incorporating paclitaxel formed an insoluble hydrogel within 30 s of ultraviolet light (UV) irradiation. The chitosan hydrogel showed strong potential for use as a new tissue adhesive in surgical applications and wound dressing. The fibroblast growth factor (FGF)-2 molecules retained in the chitosan hydrogel and in an injectable chitosan/IO₄-heparin hydrogel remain biologically active, and were gradually released from the hydrogels as they biodegraded in vivo. The controlled release of biologically active FGF-2 molecules from the hydrogels caused induction of angiogenesis and collateral circulation occurred in healing-impaired diabetic (db/db) mice and in the ischemic limbs of rats. Paclitaxel, which is an antitumor reagent, was also retained in the chitosan hydrogel and remained biologically active as it was released on degradation of the hydrogel in vivo. The chitosan hydrogels incorporating paclitaxel effectively inhibited tumor growth and angiogenesis in mice. The purpose of this review is to describe the effectiveness of chitosan hydrogel as a local drug delivery carrier for agents (e.g., FGF-2 and paclitaxel) to control angiogenesis. It is thus proposed that chitosan hydrogel may be a promising new local carrier for drugs such as FGF-2 and paclitaxel to control vascularization.