Fine structural deformation of the dermal capillary following immersion fixation procedure

The possibility of fine structural deformation related to skin biopsy and the subsequent immersion fixation procedure were investigated, because little attention has yet been focused on artifacts of the dermal microvasculature. Contraction of the material following biopsy removal was marked in skin regions with thin epidermis and resulted in capillary collapse. As the collapse of the vessels increased, lining cells became thicker and more rugged, endothelial fenestrations disappeared, and 10 nm filaments aggregated. Simultaneously, perivascular connective tissue material was separated from the dermal element in which the vessels were embedded and appeared as a homogenous areola around the endothelial tube. Basal lamina appeared folded and partially multilaminated around the vascular circumference, particularly in the venous segment of the microvasculature; these are considered to be the definite characteristics of dermal capillaries. In contrast to the skin regions with thin epidermis, the vessels in “well developed” dermal papillae did not collapse and bore close similarities to the perfused ones. The present study indicates that most of the so-called characteristics of dermal capillaries in biopsy skin is attributable to artifacts following the removal of the skin before fixation.     

Cold-induced vasodilatation in the foot is not homogenous or trainable over repeated cold exposure

Cold-induced vasodilatation (CIVD) is proposed to be a protective response to preserve tissue integrity in the extremities during cold exposure, but little research exists on either the trainability or the spatial pattern of CIVD response in the foot. We investigated the thermal response across the foot with repeated cold exposure. Ten healthy subjects immersed their left foot to the ankle in 8°C water for 30 min 5 days/week for 3 weeks. Skin temperature was recorded on the medial side of the nail bed of the 5 toes and the dorsum of the foot. The presence of CIVD, defined as an increase of 1°C at any time during cooling, was rare with our protocol. While a CIVD response was observed at least once in 8 of the 10 subjects, only 122 instances of CIVD were observed out of a total of 900 possible observations (10 subjects × 6 sites × 15 trials). Furthermore, thermal habituation was not evident, with toe temperatures at the end of each immersion (8–11°C) remaining near water temperature throughout the 15 sessions. Even within the two subjects exhibiting the most incidence of CIVD, high variability existed in the occurrence, magnitude, and/or onset times. Synchronicity was often observed where more than one toe exhibited CIVD, though the magnitude varied greatly (range 1–9°C). We conclude that, under realistic conditions of whole-foot immersion in cold water, CIVD is not a common or trainable response.     

腹腔开放伤大鼠海水浸泡后肝肾功能变化与胃黏膜损伤的关系

目的探讨腹腔海水浸泡对腹腔开放伤大鼠肝肾功能改变与胃黏膜损伤的关系。方法56只SD大鼠随机分为正常组、单纯腹部开放伤组及腹腔海水浸泡组,后两组又分为1h、2h、3h组,监测血清丙氨酸氨基转移酶(ALT)、尿素(Ure)、肌酐(Cr)及胃黏膜溃疡指数(UI)的变化。结果随着海水浸泡时间的延长,腹腔海水浸泡组大鼠胃黏膜UI与ALT、Ure、Cr均明显增高(P<0.05);且与UI存在正相关。结论腹腔海水浸泡可导致大鼠肝肾功能损伤,并与胃黏膜损伤密切相关。     

Enhanced osteointegration on tantalum-implanted polyetheretherketone surface with bone-like elastic modulus

Polyetheretherketone (PEEK) possesses a similar elastic modulus as bones but yet suffers from bio-inertness and poor osteogenesis. In this work, tantalum ions are implanted energetically into PEEK by plasma immersion ion implantation (PIII) to form Ta₂O₅ nanoparticles in the near surface. Nanoindentation reveals that the surface elastic modulus of the Ta ion implanted PEEK is closer to that of human cortical bones. In vitro cell adhesion, alkaline phosphatase activity, collagen secretion, extracellular matrix mineralization, and real-time PCR analyses disclose enhanced adhesion, proliferation, and osteogenic differentiation of rat bone mesenchymal stem cells (bMSCs) on the Ta-PIII modified PEEK. In vivo evaluation of the cortico-cancellous rat femur model by means of micro-CT, sequential fluorescent labeling, and histological analysis after 8 weeks confirms significantly improved osteointegration. The bone-like elastic modulus and modified surface topography of the Ta-PIII modified PEEK synergistically induce osteogenic differentiation of bMSCs and the surface-modified materials have large potential in dental and orthopedic implants.     

冷水束缚应激对大鼠脊髓背根神经节、胃组织内TRPV1 mRNA 及血清 SOD、MDA 的影响

目的：探讨不同时间的冷水束缚应激（ WIRS）对大鼠脊髓背根神经节（ DRG）和胃内瞬时受体电位香草酸亚型1（TRPV1） mRNA及血清超氧化物歧化酶（SOD）、丙二醛（MDA）的影响。方法选取40只雄性Wistar大鼠,随机分成4组：正常组（NC组,n＝10）、WIRS 2 h组（n＝10）、WIRS 4 h组（n＝10）和WIRS 6 h组（n＝10）,NC组不造模;WIRS 2 h组、WIRS 4 h组、WIRS 6 h组均用WIRS法复制急性胃黏膜病变模型,大鼠WIRS时间分别为2、4、6 h。于不同作用时间观察大体胃黏膜损伤变化,评定胃黏膜损伤指数;HE染色观察胃黏膜的损伤程度;实时荧光定量PCR法检测各组大鼠胸段DRG和胃内的TRPV1 mRNA的表达情况;测定各组大鼠血清中SOD、MDA的活力。结果 WIRS各组大鼠胃黏膜损伤明显,溃疡指数明显升高（ P＜0.05）。与NC组比较,WIRS各组胃组织内TRPV1 mRNA的表达均降低（ P＜0.05）;胸段DRG内TRPV1 mRNA在WIRS 6 h组的表达明显降低（ P＜0.05）。血清SOD活力先增高后降低,4 h时达到高峰;MDA随应激时间延长呈增高趋势,但在应激4 h时出现一下降过程。结论 TRPV1参与了急性胃黏膜病变的发生机制;血清中SOD、MDA的活力变化较好地反映出应激时机体氧化和抗氧化能力,有望在发现和评估应激性溃疡的发生中起重要作用。     

谷氨酰胺对腹部开放伤合并海水浸泡犬肠功能的影响研究

目的 探讨谷氨酰胺对腹部开放伤后海水浸泡实验犬肠功能的影响.方法 30只成年犬致腹部开放伤,按数字表法随机分为海水浸泡组(对照组)、普通治疗组(常规组)和谷氨酰胺治疗组(观察组),每组10只.于致伤前及致伤后定时测定犬的血压、心率、呼吸、腹围、肠鸣音,取血测定内毒素、D-乳酸、双胺氧化酶(DAO)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1(IL-1)和尿乳果糖/甘露醇(L/M),24 h后取小肠组织进行病理检查并测量肠黏膜厚度和绒毛高度.结果 与常规组比较,观察组平均动脉压、心率、呼吸、肠鸣音和腹围差异均无统计学意义(P＞0.05),对照组与常规组、观察组比较,平均动脉压、肠鸣音差异均有统计学意义(P＜0.05),致伤后12h和24 h时间点心率差异均有统计学意义(P＜0.05),致伤后24h时间点呼吸差异有统计学意义(P＜0.05),致伤后24h时间点腹围差异有统计学意义(P＜0.05).内毒素:对照组与常规组、观察组比较,致伤后12 h和24 h时间点差异均有统计学意义(P＜0.05),观察组与对照组、常规组比较,在24h时间点差异均有统计学意义(P＜0.05).D-乳酸:致伤后12 h时间点,常规组与对照组、观察组差异均有统计学意义(P＜0.05),观察组和对照组之间差异无统计学意义(P＞0.05);致伤后24 h时间点,常规组与对照组、观察组差异均有统计学意义(P＜0.05),观察组和对照组之间差异无统计学意义(P＞0.05).DAO:观察组与对照组、常规组比较,致伤后8h与24 h时间点差异均有统计学意义(P＜0.05).TNF-α:观察组与对照组、常规组比较,致伤后12 h与24 h时间点差异均有统计学意义(P＜0.05).IL-1:致伤后12 h时间点,常规组[(8.71±3.13)ng/L]与对照组[(7.40±2.71)ng/L]、观察组[(6.34±1.83)ng/L]差异均有统计学差异(P＜0.05),观察组和对照组差异无统计学意义(P＞0.05);致伤后24 h时间点,观察组[(7.44±3.11)ng/L]与对照组[(9.91±3.18)ng/L]、常规组[(10.12±2.25)ng/L]差异均有统计学意义(P＜0.05).尿L/M值:观察组(0.10±0.06)与对照组(1.07±0.04)、常规组(1.09±0.09)差异有统计学意义(P＜0.05).病理结果:观察组光镜下肠黏膜可见轻度水肿,与常规组、对照组比较明显减轻;观察组小肠黏膜厚度和绒毛高度与常规组比较差异均有统计学意义(P＜0.05);对照组与常规组比较差异均无统计学意义(P＞0.05).结论 谷氨酰胺对腹部外伤后海水浸泡导致的肠功能损伤有明确的治疗作用.     

地塞米松对大鼠烧伤合并海水浸泡后内皮祖细胞数目的影响

目的观察早期应用地塞米松对大鼠烧伤合并海水浸泡后内皮祖细胞数目的影响。方法将52只SD大鼠随机分成6组：正常对照组,单纯烧伤组,烧伤合并海水浸泡组,单纯注射地塞米松组,烧伤＋地塞米松组和烧伤合并海水浸泡＋地塞米松组。在模型制备后的30分钟、2小时、6小时和24小时,使用双色荧光标记流式细胞术检测不同组别大鼠的血中的内皮祖细胞（EPC）数目。结果烧伤和海水浸泡均可显著降低血中EPC的数目。地塞米松可以部分逆转烧伤和海水浸泡对EPC数目减少的作用。结论在烧伤和海水浸泡情况下,地塞米松的使用有助于增加血EPC数目,并可能增强创面的修复能力。     

常见热射病快速降温技术的对比评估

热射病是一种以严重高热(>40℃)和器官功能障碍为特征的紧急疾病,存在发病快、病死率高等特点。快速降温是治疗热射病的首要目标。本综述总结了目前比较常见且应用较广的快速降温技术,并根据现有研究成果对这些技术做了比较评估,以帮助医护人员在特定情况下选择最佳方案对热射病患者进行降温处理。水浸技术(1~17℃)可有效降低患者的核心体温,是目前对热射病降温最有效的降温手段。