液体复苏在高呼吸末正压通气导致的肺泡微循环障碍中的作用

目的明确高呼气末正压（PEEP）条件下肺泡微循环的变化情况以及液体复苏在高PEEP情况下对肺泡微循环的影响。 方法选用北京当地的15条健康成年杂种狗进行实验，分别观察基线（PEEP 5 cmH₂O，1 cmH₂O=0.098 kPa）、高PEEP（平均动脉压下降≥20 mmHg，1 mmHg=0.133 kPa）及液体复苏后的呼吸、系统循环及肺泡微循环情况，肺泡微循环利用旁流暗视野成像（SDF）技术进行观察、留取视频结果，线下利用AVA3.2软件进行分析，不同条件下的实验数据之间的差异利用Wilcoxon秩和检验进行分析。 结果高PEEP可导致中心静脉压（CVP）升高（P=0.001）及心输出量（CO）下降（P=0.002），肺泡微循环表现为总微血管数量（TVDa，P=0.036）、灌注血管数量（PVDa，P=0.002）、灌注血管比例（PPVa，P=0.003）、血流状态（MFIa，P=0.002）显著下降，肺泡周围毛细血管密度下降不明显（TVDs，P=0.319）；液体复苏恢复整体循环后，微循环参数均无显著改善。 结论过高的PEEP水平可导致肺泡微循环的显著恶化，通过液体复苏不能改善由此产生的微循环障碍。     

Intraoperative cerebral blood flow monitoring in neurosurgery: A review of contemporary technologies and emerging perspectives

Intraoperative monitoring of cerebral blood flow (CBF) has become an invaluable adjunct to vascular and oncological neurosurgery, reducing the risk of postoperative morbidity and mortality. Several technologies have been developed during the last two decades, including laser-based techniques, videomicroscopy, intraoperative MRI, indocyanine green angiography, and thermography. Although these technologies have been thoroughly studied and clinically applied outside the operative room, current practice lacks an optimal technology that perfectly fits the workflow within the neurosurgical operative room. The different available technologies have specific strengths but suffer several drawbacks, mainly including limited spatial and/or temporal resolution. An optimal CBF monitoring technology should meet particular criteria for intraoperative use: excellent spatial and temporal resolution, integration in the operative workflow, real-time quantitative monitoring, ease of use, and non-contact technique. We here review the main contemporary technologies for intraoperative CBF monitoring and their current and potential future applications in neurosurgery.     

丹参川芎嗪治疗冠心病心绞痛的临床疗效观察

目的:探讨丹参川芎嗪治疗冠状动脉粥样硬化性心脏病(简称冠心病)心绞痛的疗效。方法:选择住院治疗的冠心病心绞痛患者120例,随机分为观察组60例及对照组60例。对照组接受临床常规治疗,观察组在常规治疗基础上加入丹参川芎嗪治疗,均治疗2周。治疗2周后评估两组患者的临床症状变化情况,应用彩色多普勒超声诊断仪检测心功能参数,抽取外周静脉血检测一氧化氮(Nitric Oxide,NO)、组织型纤溶酶原激活物抑制剂-1(Plasminogen Activator Inhibitor-1,PAI-1)含量。结果:治疗2周后,两组的临床症状、心功能参数、NO、PAI-1含量均较治疗前优化(P<0.05)。其中观察组的心绞痛发作次数、单次发作持续时间少于对照组,疼痛程度轻于对照组(P<0.05);超声心电图参数左室舒张末期容积(EDV)、收缩末期容积(ESV)水平低于对照组,左室射血分数(LVEF)水平高于对照组(P<0.05);观察组PAI-1水平下降,NO水平升高。结论:丹参川芎嗪注射液治疗冠心病心绞痛的疗效确切,在缓解心绞痛症状、改善心功能、微循环方面具有优势。     

In vivo analysis of intestinal permeability following hemorrhagic shock

AIM: To determine the time course of intestinal permeability changes to proteolytically-derived bowel peptides in experimental hemorrhagic shock. METHODS: We injected fluorescently-conjugated casein protein into the small bowel of anesthetized Wistar rats prior to induction of experimental hemorrhagic shock. These molecules, which fluoresce when proteolytically cleaved, were used as markers for the ability of proteolytically cleaved intestinal products to access the central circulation. Blood was serially sampled to quantify the relative change in concentration of proteolytically-cleaved particles in the systemic circulation. To provide spatial resolution of their location, particles in the mesenteric microvasculature were imaged using in vivo intravital fluorescent microscopy. The experiments were then repeated using an alternate measurement technique, fluorescein isothiocyanate(FITC)-labeled dextrans 20, to semi-quantitatively verify the ability of bowel-derived low-molecular weight molecules( 20 k D) to access the central circulation.RESULTS: Results demonstrate a significant increase in systemic permeability to gut-derived peptides within 20 min after induction of hemorrhage(1.11 ± 0.19 vs 0.86 ± 0.07, P 0.05) compared to control animals. Reperfusion resulted in a second, sustained increase in systemic permeability to gut-derived peptides in hemorrhaged animals compared to controls(1.2 ± 0.18 vs 0.97 ± 0.1, P 0.05). Intravital microscopy of the mesentery also showed marked accumulation of fluorescent particles in the microcirculation of hemorrhaged animals compared to controls. These results were replicated using FITC dextrans 20 [10.85 ± 6.52 vs 3.38 ± 1.11 fluorescent intensity units(× 105, P 0.05, hemorrhagic shock vs controls)], confirming that small bowel ischemia in response to experimental hemorrhagic shock results in marked and early increases in gut membrane permeability. CONCLUSION: Increased small bowel permeability in hemorrhagic shock may allow for systemic absorption of otherwise retained proteolytically-generated peptides, with consequent hemodynamic instability and remote organ failure.     

铁蓄积骨质疏松模型凝血状态及微血栓和血管密度变化的研究

目的：了解铁蓄积骨质疏松模型中凝血状态、微血栓、微血管床及骨密度的变化,探讨骨质疏松范畴铁蓄积对凝血功能、血管方面的影响。方法：选取健康24只6月龄雄性SPF级SD大鼠,体重（250±20）g,随机分为对照组和铁蓄积组,每组12只。铁蓄积组用枸橼酸铁（ferric ammonium citrate,FAC）90 mg/kg腹腔注射干预,对照组采用等体积生理盐水腹腔注射,每周2次,干预9周。干预完成后,检测两组血清铁蛋白、凝血功能、微血栓、血管密度及股骨远端骨小梁三维形态重建和空间结构参数,并进行统计学分析。结果：铁蓄积组血清铁蛋白（136.36±35.41）μg/L较对照组（68.44±16.86）μg/L显著升高,铁蓄积组骨密度（0.167±0.024）g/cm³较对照组（0.400±0.030）g/cm³显著下降;铁蓄积组的纤维蛋白原（2.03±0.13）g/L较对照组（1.78±0.46）g/L明显升高,D-二聚体含量（534.95±31.81）ng/ml较对照组（329.02±84.99）ng/ml明显增高（P<0.05）,而凝血酶时间（39.64±2.18）s和凝血酶原时间（8.70±0.39）s较对照组（44.92±2.98）s、（9.44±0.49）s明显缩短（P<0.05）;墨汁染色后,铁蓄积组的微血管密度（17.46±2.07）%较对照组（23.81±2.98）%明显缩小（P<0.05）。HE和MSB染色均显示铁蓄积大鼠骨髓中存在微血栓,同时在心肌中也存在微血栓。结论：在铁蓄积影响的骨质疏松模型中,铁蓄积对凝血功能有显著影响,血液相对呈高凝状态,骨血管床减少,骨髓中有微血栓存在,血液的高凝状态及微血栓的形成可能是铁蓄积骨质疏松症发生的重要影响因素。     

Interframe clutter filtering for high frequency flow imaging

This study investigates 'interframe' clutter filtering with a high frequency (HF) flow imaging system with the objective of improving the performance of HF microvascular imaging at high frame rates. An interframe filter exploits the correlation of tissue signals on the time scale of the frame rate and is, therefore, insensitive to tissue spectral broadening induced by sweeping a single element transducer over a region of tissue. In vitro experiments were conducted in a tissue-mimicking flow phantom over a range of mean flow velocities (0.5 to 70.0 mm/s). Power Doppler (PD) imaging and color flow (CF) imaging were performed for both slow (0.25 fps) and fast (20 fps) scanning acquisitions. Flow data acquired at 20 fps and interframe filtered had similar velocity and mean Doppler power values as the 0.25 fps single-frame filtered data sets. In vivo validation experiments were conducted using a 500 microm blood vessel in a human finger and detected blood flow of 2 to 3 mm/s. Further in vivo experiments examining experimental murine tumors demonstrated the feasibility of performing HF PD and CF imaging at high frame rates using interframe filtering.     

影像技术在雷诺现象中的应用进展

雷诺现象是由于血管神经功能紊乱导致血管痉挛收缩、微循环障碍引起供血不足的一系列临床表现,是多种疾病的伴发症状,与疾病的进展及并发症有密切关系,是影响疾病预后及疗效的重要因素。随着技术的进步发展,越来越多的方法和技术被应用于雷诺现象的诊断及鉴别诊断。本文将影像技术在雷诺现象中的应用进展进行综述。     

Does microcirculation play a role in the pathogenesis of inflammatory bowel diseases? Answers from intravital microscopic studies in animal models

The potential role of intestinal microcirculation for the development of inflammatory bowel diseases (IBD) has not been systematically investigated, mainly because of methodological problems. Using a well-established rodent model of IBD and intravital microscopy, the present study investigated whether (and when) gut microcirculation is disturbed in IBD, and whether microcirculatory disorders contribute to histological and functional alterations in the development of IBD. Colitis was induced by rectal injection of trinitrobenzene sulfonic acid. After 1, 3, and 15 days rats were laparotomized for intravital microscopic determination of mucosal colonic blood flow. In a second series it was examined whether enhancing colonic capillary blood flow by hemodilution therapy stabilizes colonic wall resistance and other electrophysiological parameters of gut permeability. Additional measurements involved hemodynamic monitoring and histological examinations. Colonic capillary blood flow was significantly decreased 3 days after colitis induction (1.8±0.05 vs. 2.6±0.04 nl/min in healthy control animals) when histology revealed signs of acute inflammation, and normal values after 15 days (2.4±0.06 nl/min) when chronic histological changes were evident. Hemodilution therapy enhanced colonic capillary blood flow in the initial stage (2.1±0.02 vs. 1.6±0.02 nl/min in saline-treated animals with trinitrobenzene sulfonic acid colitis) and improved gut resistance and electronic chlorid secretion (73±15 vs. 33±8 μA cm²). Histological alterations were not significantly attenuated. Impaired colonic capillary blood flow in the initial stage of experimental colitis and improved mucosal microcirculation with stabilized gut permeability suggests that the early microcirculatory disturbances precede chronic histological changes and influence functional alterations in the course of the disease. Research should be continued in this field because important mechanisms in the pathogenesis of IBD and potentially therapeutic (vasoactive) substances may otherwise be overlooked. Accepted: 23 December 1998