皮肤软组织感染病原菌分布及耐药性分析

目的 调查皮肤软组织感染病原菌的种类及耐药性,为临床合理使用抗菌药物提供科学依据.方法 利用WHONET 5.6对2009年1月至2011年12月皮肤软组织感染患者脓液或分泌物细菌培养及药敏试验结果进行回顾性分析.结果 共分离菌株444株,金黄色葡萄球菌(SAU)分离率居第1位,171株占38.5％;表皮葡萄球菌居第2位,54株占12.2％;铜绿假单胞菌第3位,43株占9.7％;头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、阿米卡星、亚胺培南和美罗培南对革兰阴性杆菌有较好的抗菌活性(耐药率≤3.3％);金黄色葡萄球菌对青霉素和红霉素的耐药率为93.6％和65.0％,对呋喃妥因、利奈唑胺、利福平、莫西沙星和左旋氧氟沙星耐药率为0％、0％、1.4％、2.2％和9.3％,未检出万古霉素耐药株;耐甲氧西林金黄色葡萄球菌(MRSA)检出率25.7％ (44/171);MRSA和甲氧西林敏感金黄色葡萄球菌(MSSA)对氨苄西林/舒巴坦、利福平、莫西沙星三种药物的敏感性差异有统计学意义.结论 引起皮肤软组织感染病原菌以阳性球菌尤其是金黄色葡萄球菌为主,临床上应尽量根据药敏试验结果选用抗生素,合理用药.     

联合应用NGF 和胰岛素对糖尿病大鼠烫伤创面表皮干细胞的影响

目的:通过局部联合应用神经生长因子和胰岛素对糖尿病大鼠深II度烫伤创面表皮干细胞标记物β1整合素和角蛋白19(K19)表达的影响,探讨神经生长因子和胰岛素联合应用于糖尿病烫伤创面治疗后对创面愈合的影响。方法:雄性wistar大鼠腹腔注射链脲佐菌素(STZ)建立糖尿病模型60只,1月后在大鼠背部造成深II度烫伤。将大鼠随机分为糖尿病对照组(B)、胰岛素治疗组(C)、神经生长因子治疗组(D)、神经生长因子联合胰岛素治疗组(E),每组15只。另取15只正常雄性wistar大鼠作为正常对照组(A)。观察伤后3、7、11、15、21 d各组创面愈合情况,检测创面β1整合素和角蛋白19(K19)的表达并计算创面愈合率。结果:E组创面愈合率自第7天起较A、B、C、D组增加,为[(25.33±2.32)%,(P<0.05)];A、C、D组创面愈合率较B组增加分别为[(22.51±1.78)%,(16.68±1.95)%,(18.29±1.70)%,(P<0.05)]。E组整合素β1和角蛋白19(K19)表达自伤后第7至21天各时相点显著增加,(P<0.05)。结论:糖尿病大鼠深II度烫伤创面局部联合应用神经生长因子和胰岛素可促进表皮干细胞的增殖与分化从而加速创面的愈合。     

建立小鼠皮肤移植排斥模型稳定获得记忆T细胞

目的建立一种稳定的通过小鼠皮肤移植获得小鼠记忆T细胞的方法。方法以C57BL/6小鼠为受者、DBA/2小鼠为供者行皮肤移植;同时行C57BL/6小鼠行同种同系皮肤移植做对照。术后1-8周,每周取小鼠脾脏,使用流式细胞仪检测所有受体鼠脾单个核细胞悬液中记忆T细胞的比例（n=10）。结果（1）同种异系皮肤移植组：术后第4周的C57BL/6小鼠脾单个核细胞悬液中记忆T细胞的比例较术后1~3周显著增多（P〈0.01）;术后5~8周的记忆T细胞比例较术后第4周显著增多（P〈0.01）;术后1~3周小鼠记忆T细胞比例无差异（P〉0.05）;术后5~8周小鼠记忆T细胞比例无差异（P〉0.05）。（2）同种同系皮肤移植组：术后8周,每周产生的记忆T细胞比例无差异（P〉0.05）。结论接受同种异系皮肤抗原刺激4~5周后,小鼠记忆T细胞发生稳态增殖,此模型可以稳定的获得小鼠记忆T细胞。     

Localization of laminin α3B chain in vascular and epithelial basement membranes of normal human tissues and its down-regulation in skin cancers

The basement membrane (BM) proteins laminins, which consist of alpha, beta and gamma chains, play critical roles in the maintenance of tissue structures. One of laminin alpha chains, alpha3 has two isoforms, the truncated form alpha3A and the full-sized form alpha3B. In contrast to alpha3A laminins, little is known about alpha3B laminins. To show the histological distribution of the laminin alpha3B chain, we prepared alpha3B-specific monoclonal antibodies. Immunohistochemical analysis showed that the alpha3B chain was colocalized with the alpha3A, beta3 and gamma2 chains in the epithelial BMs of the skin, esophagus, breast and lung, suggesting the presence of laminin-3B32 (laminin-5B) and laminin-3A32 (laminin-5A). In the lung alveoli, laminin-3B32 was dominant over laminin-3A32, but vice versa in other epithelial BMs. In contrast, the BMs of blood vessels including capillaries were strongly positive for alpha3B, but almost or completely negative for alpha3A, beta3 and gamma2. alpha3B was colocalized with beta1 and gamma1 in these BMs. The alpha3B chain was scarcely detected in the vessels of malignant skin cancers, though the gamma2 and beta3 chains were highly expressed in the cancer cells. These results strongly suggest that the laminin alpha3B chain is widely expressed in vascular BMs of normal tissues, probably as laminin-3B11/3B21 (laminin-6B/7B).     

A simplified model of scar contraction

The healing of wounds is a complex process and the contraction of the resulting scar can have a negative impact on the neighbouring skin. A finite element model of skin simulating the contraction of a scar and deformation of the surrounding skin is presented. The skin is represented by an orthotropic–viscoelastic constitutive law, which is validated against experimental data in the literature. A simplified experimental model of a contracting scar in real skin is also developed. The pattern and size of the wrinkles formed around the contracting scar in the finite element model compare favourably with those formed in the experimental model. The orthotropic nature of skin plays a significant role in the behaviour of skin around scars—the wrinkles have a preferential orientation that corresponds to a direction perpendicular to the Langer's lines in the skin. The pre-stress in skin (a property that is ignored in many skin models) is shown to be an important factor in wrinkle formation around scars. The proposed model can be used to analyse the suturing and closure of wounds of various shapes.     

A novel family of antimicrobial peptides from the skin of Amolops loloensis

While conducting experiments to investigate antimicrobial peptides of amphibians living in the Yunnan-Sichuan region of southwest China, a new family of antimicrobial peptides was identified from skin secretions of the rufous-spotted torrent frog, Amolops loloensis. Members of the new peptide family named amolopins are composed of 18 amino acids with a unique sequence, for example, NILSSIVNGINRALSFFG. By BLAST search, amolopins did no show similarity to any known peptides. Among the tested microorganisms, native and synthetic peptides only showed antimicrobial activities against Staphylococcus aureus ATCC2592 and Bacillus pumilus, no effects on other microorganisms. The CD spectroscopy showed that it adopted a structure of random combined with beta-sheet in water, Tris-HCl or Tris-HCl-SDS. Several cDNAs encoding amolopins were cloned from the skin cDNA library of A. loloensis. The precursors of amolopin are composed of 62 amino acid residues including predicted signal peptides, acidic propieces, and mature antimicrobial peptides. The preproregion of amolopin precursor comprises a hydrophobic signal peptide of 22 residues followed by an 18 residue acidic propiece which terminates by a typical prohormone processing signal Lys-Arg. The preproregions of precursors are very similar to other amphibian antimicrobial peptide precursors but the mature amolopins are different from other antimicrobial peptide families. The remarkable similarity of preproregions of precursors that give rise to very different antimicrobial peptides in distantly related frog species suggests that the corresponding genes form a multigene family originating from a common ancestor.     

Immunolocalization of a mammalian aquaporin 3 homolog in water-transporting epithelial cells in several organs of the clawed toad Xenopus laevis

Nucleotide sequences of cDNA were used to construct antibodies against an aquaporin (AQP) expressed in the clawed toad, Xenopus laevis, viz., Xenopus AQP3, a homolog of mammalian AQP3. Xenopus AQP3 was immunolocalized in the basolateral membrane of the principal cells of the ventral skin, the urinary bladder, the collecting duct and late distal tubule of the kidney, the absorptive epithelial cells of the large intestine, and the ciliated epithelial cells of the oviducts. Therefore, we designated this AQP as basolateral Xenopus AQP3 (AQP-x3BL). The intensity of labeling for AQP-x3BL differed between the ventral and dorsal skin, with the basolateral membrane of the principal cells in the ventral skin showing intense labeling, whereas that in the dorsal skin was lightly labeled. AQP-x3BL was also immunolocalized in the basolateral membrane of secretory cells in the small granular and mucous glands of the skin. As AQP-x5, a homolog of mammalian AQP5, is localized in the apical membrane of these same cells, this provides a pathway for fluid secretion by the glands. Although Hyla AQP-h2 is translocated from the cytoplasm to the apical membrane of the Hyla urinary bladder in response to arginine vasotocin (AVT), AQP-h2 immunoreactivity in Xenopus bladder remains in the cytoplasm and barely moves to the apical membrane, regardless of AVT stimulation. AQP-x3 is localized in the basolateral membrane, even though the AVT-stimulated AQP-h2 does not translocate to the apical membrane. These findings provide new insights into AQP function in aquatic anurans.     

Skin thermal pain modeling—A holistic method

Pain sensation has been studied extensively, over a range of scales, from the molecular level to the entire human neural system. Thermal stimulation of pain has been widely used in the study of pain sensation. Skin thermal pain is induced through both direct (an increase/decrease in temperature) and indirect (thermomechanical and thermochemical) ways, and is governed by complicated thermomechanical–chemical–neurophysiologic responses. This paper is focused on the theoretical modeling of the underlying mechanisms in the process of skin thermal pain. A holistic model has been developed, which is composed of three sub-models, namely, transduction, transmission, and modulation and perception. The model can contribute to the understanding of thermally related pain phenomena in skin tissue and to improvements in a range of thermal therapeutic methods.