Nonoperative management of a giant omphalocele using a silver impregnated hydrofiber dressing: a case report

The surgical management of a giant omphalocele is challenging. Many cannot be closed at birth and must initially be managed nonoperatively with a topical agent to facilitate epithelialization. We report the case of a term, 1-day-old female neonate with a giant omphalocele treated initially with a hydrofiber dressing containing silver (Aquacel Ag; ConvaTec Inc, Skillman, NJ) and then with delayed primary closure.     

急救烧伤敷料结构设计、物理性能和临床应用

目的 对急救烧伤敷料进行结构设计，通过有关性能测试和临床应用来验证其结构设计的合理性。方法 根据急救烧伤敷料的使用要求将该敷料设计成双层结构，并对该敷料进行红外光谱，物理性能测试和临床疗效观察；结果 红外光谱测定证实了敷料的双层结构；物理性能测试表明该敷料具有较好的吸水力，强度及弹性，而且透气性，透湿性适宜；临床疗效观察也表明该敷料能够较好地吸收创面渗出液，不粘连创面，对创面刺激小，具有一定的止血和抗感染作用。能够促进创面愈合，多种规格，使用方便等特点，尤其适用于烧伤创面的急救包扎。结论 该急救烧伤敷料的结构设计具有合理性。     

医用负压封闭引流聚氨酯泡沫材料的制备及性能研究

目的通过聚氨酯发泡制备出能应用于负压封闭引流技术的聚氨酯敷料。方法通过正交实验设计聚氨酯泡沫一步法发泡工艺,并对制备的聚氨酯泡沫进行物理机械性能测试和表面形态观察,从中选取出一组综合性能最佳的聚氨酯泡沫配方,并对其进行优化设计。对优化配方制备的聚氨酯泡沫进行细胞毒性和溶血实验生物学评价。结果制备的聚氨酯泡沫的表观密度为20~35 kg/m3,拉伸强度为16~21 N。细胞体外毒性测试所得细胞相对增殖率为90.1%,符合国家细胞毒性安全标准。聚氨酯泡沫溶血率为2.53%,低于5%的国家标准。一步法发泡所制备的聚氨酯泡沫具有良好的物理机械性能和生物相容性。结论聚氨酯泡沫作为医用负压引流材料具有良好的应用前景,但还需对负压引流效果及其他生物相容性进行进一步的测试。     

Agonists of PPAR-α, PPAR-γ, and RXR inhibit the formation of foam cells from macrophages in mice with inflammation

We studied the effect of agonists of peroxisome proliferator-activated receptors α and γ and retinoid X receptors on the concentration and synthesis of lipids in macrophages of C57Bl/6 mice with inflammation induced by intraperitoneal injection of zymosan. We revealed a significant increase in [1-¹⁴C]oleate incorporation into cholesterol esters and triglycerides, increase in the content of free cholesterol, cholesterol esters, and triglycerides, and formation of oil red-stained lipid inclusions in peritoneal macrophages 24 h after administration of zymosan in a dose of 50 mg/kg. Treatment with agonists of retinoid X receptors and peroxisome proliferator-activated receptors α and γ 30 min before and 12 h after zymosan injection decreased the synthesis of triglycerides and cholesterol esters, reduced the content of free cholesterol, cholesterol esters, and triglycerides in macrophages, and prevented the formation of cytoplasmic lipid inclusions in macrophage-derived foam cells during inflammation. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 11, pp. 556–559, November, 2007     

Pectin-chitosan-PVA nanofibrous scaffold made by electrospinning and its potential use as a skin tissue scaffold

Scaffolds made of chitosan nanofibers are often too mechanically weak for their application and often their manufacturing processes involve the use of harmful and flammable organic solvents. In the attempt to improve the mechanical properties of nanofibrous scaffolds made of chitosan without the use of harmful chemicals, pectin, an anionic polymer was blended with chitosan, a cationic polymer, to form a polyelectrolyte complex and electrospun into nanofibers for the first time. The electrospun chitosan-pectin scaffolds, when compared to electrospun chitosan scaffolds, had a 58% larger diameter, a 21% higher Young’s modulus, a 162% larger strain at break, and a 104% higher ultimate tensile strength. Compared to the chitosan scaffolds, the chitosan-pectin scaffolds’ swelling ratios decreased by 55% after 60?min in a saline solution and more quickly released the preloaded tetracycline HCl. The L929 fibroblast cells proliferated slightly slower on the chitosan-pectin scaffolds than on the chitosan scaffolds. Nonetheless, cells on both materials deposited similar levels of extracellular type I collagen on a per DNA basis. In conclusion, a novel chitosan-pectin nanofibrous scaffold with superior mechanical properties than a chitosan nanofibrous scaffold was successfully made without the use of harmful solvents.     

Wound dressing composed of hyaluronic acid and collagen containing EGF or bFGF: comparative culture study

We developed a novel wound dressing composed of a hyaluronic acid (HA) and collagen (Col) spongy sheet containing epidermal growth factor (EGF) or basic fibrolast growth factor (bFGF) by freeze-drying method (EGF-wound dressing or bFGF-wound dressing, respectively). A wound dressing without any growth factor was prepared as a control in a similar manner as above (C-wound dressing). Intermolecular cross-linkage between Col molecules was induced by UV irradiation. The release behavior of free HA from the wound dressing was investigated using a C-wound dressing. The weight of C-wound dressing after 1 day, 3, 5, and 7?days of incubation on top of a Col gel sheet at the air–water interface (wound surface model) was 55, 36, 30, and 19% of the original weight, respectively. Most free HA and a part of Col was released from the cross-linked Col network in the wound dressing during incubation, as the original Col content in the wound dressing was 33%. Next, fibroblast proliferation was assessed in conventional culture medium preconditioned by immersion of a piece of C-, EGF-, or bFGF-wound dressing, i.e. C-conditioned medium, EGF-conditioned medium, or bFGF-conditioned medium. Cell proliferation in C-conditioned medium increased to approximately the same level as that in conventional medium. Cell proliferation in EGF- and bFGF-conditioned medium was 1.9 times and 2.6 times greater than that in conventional medium after 7?days of cultivation, respectively. Finally, cytokine production of fibroblasts was assessed in a wound surface model using a fibroblast-incorporating Col gel sheet (cultured dermal substitute [CDS]). CDS was elevated to the air–medium interface, on which each wound dressing was placed and cultured for 7?days. Fibroblasts in CDS covered with EGF-wound dressing released 3.6 times more vascular endothelial growth factor (VEGF) and 4.6 times more hepatocyte growth factor (HGF) when compared with the C-wound dressing. Fibroblasts in CDS covered with bFGF-wound dressing released 10.2 times more VEGF and 6.3 times more HGF when compared with the C-wound dressing. This finding indicates that bFGF-wound dressing can facilitate more effectively the VEGF and FGF production compared with EGF-wound dressing.     

Chitosan nanoparticle/PCL nanofiber composite for wound dressing and drug delivery

Many investigations of wound dressings equipped with drug delivery systems have recently been conducted. Chitosan is widely used not only as a material for wound dressing by the efficacy of its own, but also as a nanoparticle for drug delivery. In this study, an electrospun polycaprolactone nanofiber composite with chitosan nanoparticles (ChiNP–PCLNF) was fabricated and then evaluated for its drug release and biocompatibility to skin fibroblasts. ChiNP–PCLNF complexes showed no cytotoxicity and nanoparticles adsorbed by van der Waals force were released into aquatic environments and then penetrated into rat primary fibroblasts. Our studies demonstrate the potential for application of ChiNP–PCLNF as a wound dressing system with drug delivery for skin wound healing without side effects.     

Controlling Fibroblast Proliferation with Dimensionality-Specific Response by Stiffness of Injectable Gelatin Hydrogels

Abstract

We report an injectable hydrogel system with tunable stiffness for controlling the proliferation rate of human fibroblasts (HFF-1) in both two-dimensional (2D) and three-dimensional (3D) culture environments for potential use as a wound dressing material. The hydrogel composed of gelatin–hydroxyphenylpropionic acid (Gtn–HPA) conjugate was formed by the oxidative coupling of HPA moieties catalyzed by hydrogen peroxide (H₂O₂) and horseradish peroxidase (HRP). The stiffness of the hydrogels was controlled well by varying the H₂O₂ concentration. The effects of hydrogel stiffness on the proliferation rate of HFF-1 in both 2D and 3D were investigated. We found that the proliferation rate of HFF-1 using Gtn–HPA hydrogels was strongly dependent on the hydrogel stiffness, with a dimensionality-specific response. In the 2D studies, the HFF-1 exhibited a higher proliferation rate when the stiffness of the hydrogel was increased. In contrast, the HFF-1 cultured inside the hydrogel remained non-proliferative for 12 days before a stiffness-dependent proliferation profile was shown. The proliferation rate decreased with an increase in stiffness of the hydrogel in a 3D culture environment, unlike in a 2D environment.     

Porosity and biological properties of polyethylene glycol-conjugated collagen materials

Collagen-based materials can be designed for use as scaffolds for connective tissue reconstruction. The goal of the present study was to evaluate the behavior of collagen materials as well as cell and tissue reactions after the conjugation of activated polyethylene glycols (PEGs) with collagen. It is known that proteins conjugated with PEGs exhibit a decrease in their biodegradation rate and their immunogenicity. Different concentrations and molecular weights of activated PEGs (PEG-750 and PEG-5000) were conjugated to collagen materials (films or sponges) which were then investigated by collagenase assay, fibroblast cell culture, and subcutaneous implantation. PEG-conjugated collagen sponge degradation by collagenase was delayed in comparison to untreated sponges. In culture, fibroblasts with a normal morphology reached confluency on PEG-conjugated collagen films. In vivo, the porous structure of non-modified sponges collapsed by day 15 with a few observable fibroblasts between the collagen fibers. In PEG-modified collagen sponges, the porous structure remained stable for 30 days. Cell infiltration was particularly enhanced in PEG-750-conjugated collagen sponges. In conclusion, PEGs conjugated onto collagen sponges stabilize the porous structure without deactivating the biological properties of collagen. These porous composite materials could function as a scaffold to organize tissue ingrowth.     

细胞亲环素A对单核来源泡沫细胞功能的影响

目的:研究细胞亲环素A对单核来源泡沫细胞功能的影响,探讨细胞亲环素A(CypA)在动脉粥样硬化发病过程中的作用。方法:以氧化型低密度脂蛋白诱导,建立人单核细胞系(THP-1细胞)分化的泡沫细胞模型,采用油红O染色进行形态学鉴定。以不同浓度的重组人CyPA(50、100、200μg/L)刺激人单核来源的泡沫细胞,通过细胞黏附实验、基质侵袭实验和明胶酶谱实验检测在分化的过程中CypA作用前后,MMP的表达,细胞黏附和侵袭力的变化。进而用环孢素A(CsA)、HAb18 mAb、c7b8 f10以及HAb18 mAb联合c7b8 f10分别进行阻断实验,观察对泡沫细胞功能的抑制作用。结果:在单核向泡沫细胞分化的各阶段中,泡沫细胞MMP-2、9的表达,黏附基质和侵袭能力均较THP-1单核株和巨噬细胞显著增强(P<0.05);CyPA对泡沫细胞上述功能有促进作用,浓度100~200μg/L的作用效果最明显(P<0.05);以上拮抗剂均可不同程度阻断CypA作用于泡沫细胞前后的上调作用,其中以HAb18 mAb联合c7b8 f10的抑制作用最明显(P<0.05)。结论:CypA上调了动脉粥样硬化泡沫细胞MMP-2、9的表达及其活性,增强了泡沫细胞黏附、侵袭能力,其促进作用可被CypA和CD147的拮抗剂所抑制。这一作用机制可能与动脉粥样硬化斑块不稳定性的发病机制相关联,并为其治疗提供了新的理论基础。