Formation and differentiation of the avian dermomyotome

During somite maturation, the ventral half of the epithelial somite disintegrates into the mesenchymal sclerotome, whereas the dorsal half forms a transitory epithelial sheet, the dermomyotome, lying in between the sclerotome and the surface ectoderm. The dermomyotome is the source of most of the mesodermal tissues in the body, giving rise to cell types as different as muscle, connective tissue, endothelium, and cartilage. Thus, the dermomyotome is the most important turntable of mesodermal cell fate choice in the vertebrate embryo. Here, we discuss the current knowledge on the formation of the dermomyotome and the mechanisms leading to the development of the various dermomyotomal derivatives, with special emphasis on the development of musculature and dermis.     

Dermofat Graft in Deep Nasolabial Fold and Facial Rhytidectomy

Fat and dermis or the combined tissues are used commonly in augmentation of the nasolabial fold. Guyuron obtained the dermofat graft from either the suprapubic or the groin region. The thickness of the preauricular skin was measured in seven Korean cadavers, five male and two female. We used the dermofat graft out of the preauricular skin remnant after facial rhytidectomy to augment the deep nasolabial fold in a patient. The average thickness of the epidermis was 56 ± 12 µm, the dermis was 1820 ± 265 µm thick, and the subcutaneous tissue was 4783 ± 137 µm. More dense connective tissues, such as SMAS, are seen in the preauricular skin. The dermofat graft was easily obtained and prepared from the leftover preauricular skin after dissection of the lax skin in face lifting. This technique could be employed effectively and successfully to alleviate a deep nasolabial fold and concomitant facial rhytidectomy in an Asian with a thick preauricular skin.     

黏着斑微操控在创伤和组织修复中的作用

目的 探讨真皮模板单元-黏着斑微操控制对皮肤成纤维细胞生物学行为影响. 方法 采用微图案方法制作微凸阵列,运用分子自组装在微凸上自组装结构蛋白分子,在自制细胞培养仪模拟皮肤生物力学进行细胞牵拉2周,并行形态学观察和细胞免疫组织化学分析. 结果 细胞牵拉2周后,细胞形态多样、丰满,分泌增加,呈现顺应性.细胞免疫组织化学分析发现,整合素β1、α5表达较对照显著减少,张力蛋白tensin表达显著降低. 结论 通过黏着斑微操控,增生性瘢痕成纤维细胞在形态学及生物学行为上发生改变.     

创伤局部微环境对大鼠真皮多能干细胞生物学性状的影响

目的：研究创伤局部微环境对大鼠真皮多能干细胞生物学性状的影响。方法：将大鼠真皮多能干细胞经荧光染料DAPI标记后，植入受损的皮肤组织，荧光显微镜观察标记细胞的植入情况；体外四唑盐（MTT）法和划痕实验检测急性皮肤创伤伤口液对大鼠真皮多能干细胞增殖和迁移的影响。进一步将大鼠真皮多能干细胞置入透析袋中并植入大鼠背部伤口作用3d，免疫组化法检测碱性成纤维细胞生长因子（bFGF)，神经生长因子（NGF），一种生长因子的辅受体syndecan-1的表达。结果：移植14d后，DAPI标记的真皮多能干细胞主要位于真皮和皮下组织；体积分数为10％的伤口液在体外促进真皮多能干细胞的增殖和迁移的能力最强；大鼠背部伤口局部微环境作用3d后，真皮多能干细胞高表达bFGF,NGF等生长因子和syndecan-1。结论：创伤局部微环境可通过诱导真皮多能干细胞的增殖，运动和分化而直接参与修复，同时还可通过调控生长因子和辅助受体的表达而间接促进修复。     

大鼠深Ⅱ度烧伤创面保留变性真皮并覆盖自体皮疗效观察

目的为探讨自体皮覆盖变性真皮修复深Ⅱ度烧伤创面的可行性提供实验依据。方法在大鼠背部造成直径3.5cm深Ⅱ度烧伤创面。伤后2—5d行创面浅层削痂保留变性真皮,同时在局部移植大张自体断层皮片。移植前和移植后不同时相点分别切取植皮区全层皮肤,光镜下观察其形态学及胶原纤维变化,并检测其生物力学改变。取移植大鼠同体背部正常皮肤作为对照指标。结果(1)保留的变性真皮为玻璃样变性。(2)大鼠自体皮移植术后7d,皮片与创面融合无法分离,光镜下可见真皮乳头及网状层。术后21d移植部位皮肤厚度、结构、形态与正常组织相似,有萎缩毛囊,胶原纤维条索密度逐渐增大接近融合。(3)鼠皮抗拉强度、最大应变值在术后逐渐增大,至60d时接近正常。结论将自体皮覆盖于变性真皮上用以修复深Ⅱ度烧伤创面,变性真皮能够逐渐复苏,使其结构、形态接近正常。     

Ultrasonic propagation properties of excised human skin

Eight human skin samples were excised postmortem from the upper and lower back, chest and abdomen from two cadavers. The acoustical speed, attenuation and backscatter were measured as a function of frequency (20 to 30 MHz) at 100 positions on a uniform grid over a cross-sectional slice through each sample with the sound incident in a direction parallel to the skin surface. Measurements were made at 24 ± 0.5°C. Samples were then frozen, cut and stained for histological examination and quantification of fibrous proteins and fat content. The mean attenuation coefficients obtained for whole skin agreed well with previously published results. Employing the model = ₁ƒⁿ where is the attenuation coefficient in decibels per centimeter, ₁ is the value of the attenuation coefficient at 1 MHz and ƒ is frequency raised to the power n, mean values (±1 standard deviation) for epidermis were ₁ = 0.44 ± 0.26 and N = 1.55 ± 0.12, and for dermis ₁ = 0.264 ± 0.17 dB cm⁻¹ and N = 1.69 ± 0.084. Using a similar model the mean backscatter coefficient was defined by μ₁ = (5.01 ± 25.76) × 10⁻⁸Sr⁻¹ cm⁻¹, n = 3.77 ± 1.5 for the epidermis, and μ₁ = (1.79 ± 19.5) × 10⁻⁶ and n = 2.76 ± 1.4 for the dermis. The speed of sound values fell within the range to be found in the literature with a mean value in the epidermis of 1645 m s⁻¹ and in the dermis of 1595 m s⁻¹. Significant, strong correlation existed between the spatially averaged fibrous protein content in the epidermis and dermis and the spatially averaged integrated attenuation measurements. Likewise, strong correlation existed between integrated backscatter and fibrous protein content in the epidermis but not in the dermis. Further research is required to confirm these preliminary findings and to evaluate the role of collagen fibre orientation as a source of variation in the backscattering coefficient of dermis.     

Successful treatment of an extensive form of aplasia cutis congenita by dermis grafts

Summary This is a report of an extensive form of aplasia cutis congenita in a male newborn with normal family history, normal birth and no other anomalies. The deformity was located on the lower and lateral part of the thorax extending to the axillae and including the whole abdominal wall. A small skin area of 2 cm radius around the umbilicus and 2 cm wide on each side of the lumbar spine were normal. This entire defect was covered by a transparent membrane through which the movement of the lungs, the liver and the bowel could be observed. The segmental intercostal vessels and nerves were visible. The transparent membrane consisted of two very thin layers; the inner one was thought to be the peritoneum, and the outer one showed malformed epithelium and a few muscles under the electronmicroscope. A few smaller lesions were found on the hairy scalp on both sides of the midline and on both thighs. Surgical treatment was performed with multiple dermis grafts taken from different parts of th body sutured together to form one piece and inserted between the two layers of the lesion. In two weeks time complete epithelialisation occured except over one small granulating defect which was covered with a mesh graft. There were no postoperative complications and the infant showed normal development with normal weight gain and growth. No scar contracture has been observed and even signs of some muscle activity in the abdominal wall can be detected.     

Effects of a positively charged biomaterial for dermal and subcutaneous augmentation

Based on previous experimental connective tissue work, the use of a positively charged dextran-based biomaterial in subcutaneous tissue sites was evaluated. After hydration with saline, the biomaterial was injected beneath the abdominal skin in rats. A robust macrophage response was initially seen at 30 days without acute inflammation. By one year postoperatively, extensive intermaterial fibroblast and collagen ingrowth had occurred. No evidence of a foreign-body or chronic inflammatory response was seen. These preliminary findings suggest good tissue compatibility of this biomaterial and suggests that when combined with a biocompatible liquid medium, the potential for development of a bioactive dermal and subcutaneous injectable substance exists.     

Myoepitheliale Tumoren der Haut und des Weichgewebes

Zusammenfassung Myoepitheliale Tumoren der Haut und des Weichgewebes umfassen kutane Mischtumoren (chondroide Syringome), Mischtumoren der Subkutis und des tiefen Weichgewebes, Myoepitheliome und die seltenen malignen Myoepitheliome (myoepitheliale Karzinome). Wie auch in anderen anatomischen Lokalisationen sind Myoepitheliome der Haut und des Weichgewebes durch eine außerordentliche klinisch-pathologische Heterogenität charakterisiert. Die Tumoren entstehen sowohl im Kindes- als auch im Erwachsenenalter und bestehen aus epithelioiden, histiozytoiden, spindeligen, plasmozytoiden und/oder klarzelligen Tumorzellen in wechselnder Zusammensetzung, die in einer myxoiden oder hyalinisierten Matrix angeordnet sind. Immunhistochemisch nachweisbar werden von den Tumoren epitheliale Marker (Panzytokeratin und/oder epitheliales Membranantigen), häufig S-100 Protein sowie teilweise muskuläres Aktin, gliales saures Faserprotein, Calponin und p63 exprimiert, während Desmin in der Regel nicht zu detektieren ist. Der Nachweis mittel- bis hochgradiger zytologischer Atypien ist in Myoepitheliomen mit einer verschlechterten Prognose assoziiert, und maligne Myoepitheliome können in einer signifikanten Anzahl von Fällen metastasieren und zum Tode der betroffenen Patienten führen.     

Outdoor post-mortem bite injuries by Tapinoma nigerrimum (Hymenoptera,Formicidae) on a human corpse: Case report

Ants are among the insects that colonize exposed human and animal corpses during the early stage of decomposition. In Calabria, Italy (as well as in other countries), Formicidae have been observed preying on immature stages of Diptera and other insects, as well as causing irregular scalloped areas of superficial skin loss on human corpses and animal carcasses. We present a case of injuries on a human corpse caused by ant feeding. The macroscopic appearance is described and the results of a histochemical investigation of the skin lesions caused by worker ants are reported for the first time. The investigation was carried out on the fresh corpse of a 53-year-old man discovered in a rural area of Cosenza province (Calabria, southern Italy). Numerous irregular areas of superficial skin loss caused by the ant Tapinoma nigerrimum (Nylander 1856) (Hymenoptera, Formicidae) were observed on the body surface, inflicted very early in the post-mortem period. Because the classification of lesions is of crucial importance for forensic investigations, the macroscopic appearance and distribution pattern of the lesions on the corpse are illustrated. The histochemical investigation of the damaged skin explains, for the first time, the mechanism of production of the lesions.