Ischemic Tissue Injury in the Dorsal Skinfold Chamber of the Mouse: A Skin Flap Model to Investigate Acute Persistent Ischemia

Despite profound expertise and advanced surgical techniques, ischemia-induced complications ranging from wound breakdown to extensive tissue necrosis are still occurring, particularly in reconstructive flap surgery. Multiple experimental flap models have been developed to analyze underlying causes and mechanisms and to investigate treatment strategies to prevent ischemic complications. The limiting factor of most models is the lacking possibility to directly and repetitively visualize microvascular architecture and hemodynamics. The goal of the protocol was to present a well-established mouse model affiliating these before mentioned lacking elements. Harder et al. have developed a model of a musculocutaneous flap with a random perfusion pattern that undergoes acute persistent ischemia and results in ~50% necrosis after 10 days if kept untreated. With the aid of intravital epi-fluorescence microscopy, this chamber model allows repetitive visualization of morphology and hemodynamics in different regions of interest over time. Associated processes such as apoptosis, inflammation, microvascular leakage and angiogenesis can be investigated and correlated to immunohistochemical and molecular protein assays. To date, the model has proven feasibility and reproducibility in several published experimental studies investigating the effect of pre-, peri- and postconditioning of ischemically challenged tissue.     

小剂量肝素治疗皮神经营养皮瓣术后静脉危象的探讨

目的：探讨小剂量肝素治疗皮神经营养皮瓣术后静脉危象的临床价值。方法：我院自2010年1月至10月共5例发生皮神经营养皮瓣术后皮瓣出现静脉危象。所有5例患者均在间断拆线的同时应用皮瓣皮下小剂量肝素注射使切缘持续缓慢渗血,并根据血运情况调整肝素使用剂量,观察皮瓣血运恢复情况及存活情况。结果：经小剂量肝素治疗后,5例皮神经营养皮瓣术后皮瓣颜色转红润,静脉危象均逐步缓解,全部皮瓣均成活,伤口无感染,愈合良好。患者对皮瓣外观和功能满意。结论：小剂量肝素皮下注射是一种简易但有效的解决皮神经营养皮瓣术后静脉危象的方法。     

足踝骨肿瘤切除后采用腓肠神经营养血管皮瓣术的修复效果及对运动功能的影响

摘要 目的：探讨足踝骨肿瘤切除后采用腓肠神经营养血管皮瓣术的修复效果及对运动功能的影响。方法：选取我院2013~2019年收治的足踝骨肿瘤切除患者83例,应用随机分组法将其分为研究组41例和对照组42例。对照组患者应用以往清创换药的保守修复方法,研究组患者应用腓肠神经营养血管皮瓣术修复方法,对比两组患者的治疗总有效率与致残率、住院费用、住院时间以及治疗前后运动功能的变化。结果：治疗后,研究组的总有效率为90.24%,显著高于对照组(64.29%,P＜0.05);两组患者住院花费比较差异无统计学意义(P＞0.05);研究组患者的住院天数上明显短于对照组(P＜0.05);研究组患者的致残率为2.44%,明显低于对照组(16.67%,P＜0.05);研究组患者修复后的Fugl-Meyer下肢运动功能评定(Fugl-Meyer assessment,FMA)和Berg平衡量表(Berg Balance Scale,BBS)评分均明显高于对照组(P＜0.05)。结论：腓肠神经营养血管皮瓣术修复术较清创换药的保守修复方法可以更有效修复足踝骨肿瘤广泛切除术后患者足踝部的创伤面,改善患者运动功能,且手术方法相对简单,安全性更高。     

背阔肌肌皮瓣修复肩背部软组织肉瘤术后缺损研究

目的：分析背阔肌肌皮瓣在肩背部软组织肉瘤扩大切除术后缺损修复中的方便性及优越性。方法：选取临床确诊肩背部软组织肉瘤患者8例,行肩背部病灶扩大切除术后,依据背阔肌肌皮瓣解剖学特点,选择合适的背阔肌肌皮瓣转移修复肩背部缺损。结果：皮瓣全部存活,随访6月至28月,肩背部外形满意,日常活动无明显影响。结论：应用背阔肌肌皮瓣修复肩背部软组织肉瘤扩大术后缺损是一种行之有效的方法。该方法简单易行,临床效果明显。     

Investigation of flap flexibility of β-secretase using molecular dynamic simulations

Flap motif and its dynamics were extensively reported in aspartate proteases, e.g. HIV proteases and plasmepsins. Herein, we report the first account of flap dynamics amongst different conformations of β-secretase using molecular dynamics simulation. Various parameters were proposed and a selected few were picked which could appropriately describe the flap motion. Three systems were studied, namely Free (BACE_Free) and two ligand-bound conformations, which belonged to space groups P6₁22 (BACE_Bound1) and C222₁ (BACE_Bound2), respectively and four parameters (distance between the flaps tip residue, Thr72 and Ser325, d₁; dihedral angle, ? (Thr72-Asp32-Asp228-Ser325); TriCα angles, θ₁ (Thr72-Asp32-Ser325), and θ₂ (Thr72-Asp228-Ser325)) were proposed to understand the change in dynamics of flap domain and the extent of flap opening and closing. Analysis of, θ₂, d₁, θ₁ and ? confirmed that the BACE_Free adopted semi-open, open and closed conformations with slight twisting during flap opening. However, BACE_Bound1 (P6122) showed an adaptation to open conformation due to lack of hydrogen bond interaction between the ligand and flap tip residue. A slight flap twisting, ? (lateral twisting) was observed for BACE_Bound1 during flap opening which correlates with the opening of BACE_Free. Contradictory to the BACE_Bound1, the BACE_Bound2 locked the flap in a closed conformation throughout the simulation due to formation of a stable hydrogen bond interaction between the flap tip residue and ligand. Analyses of all three systems highlight that d₁, θ₂ and ? can be precisely used to describe the extent of flap opening and closing concurrently with snapshots along the molecular dynamics trajectory across several conformations of β-secretase.     

改良双侧V-Y皮瓣治疗Ⅳ期骶尾部压疮的疗效分析

摘要 目的：探讨改良双V-Y皮瓣治疗Ⅳ期骶尾部压疮的有效性和安全性。方法：回顾性分析2015年3月-2019年3月中国人民解放军总医院第七医学中心骨科收治骶尾部压疮Ⅳ期患者28例,其中男15例,女13例,年龄49-65岁,创面面积6 cm×7 cm~8 cm×10 cm。彻底清创后设计改良双侧V-Y推移皮瓣覆盖创面并行负压封闭引流,皮瓣供区减张缝合,皮瓣面积6 cm×7 cm~8 cm×10 cm。术后观察皮瓣整体血运、温度、水肿情况及VSD引流量,定期通过门诊、微信、电话随访。结果：手术后双侧V-Y皮瓣全部成活,1例术后切口周边皮肤表皮坏死,经换药后愈合,28例患者全部获得随访,随访时间12-24个月,平均18.2个月,全部压疮缺损修复成功,无创口裂开、皮瓣淤血、水肿、感染及压疮复发。结论：改良双侧V-Y推移皮瓣是治疗Ⅳ期骶尾部压疮的一种有效治疗方法。     

前臂皮瓣修复外伤性颌面部缺损的护理体会

目的:探讨颌面部外伤后遗留大面积软组织缺损采用血管化游离前臂皮瓣修复的护理方法。方法:采用前臂皮瓣血管吻合修复17例外伤导致的颌面部软组织缺损,围术期采取严格的护理措施,术前的心理护理、术后的严密观察,最大限度防止皮瓣血管危象发生,保证治疗效果。结果:2例出现血管危象,进行抢救,其中1例失败,另1例抢救成功,其余15例顺利成活。结论:术前进行心理护理、术后严密观察、及时抢救是确保手术成功的关键。