组织工程学研究中偏光显微镜的应用

偏光显微镜是地质界用来观察晶体矿物的重要仪器，其理论基础是结晶光学，特点是即可观察结构，又可根据光学性质（折光率值不同）来判断成分，通过在研究ＮＥＣＭ和注射性胶原制作的过程中，用偏光显微镜和光镜观察同一部位的组织片，加以对比分析。因为胶原是生物体内的特殊“晶体”，故认为偏光显微镜应用在组织工程研究中，不仅开阔了观察领域，而且是重要的观测手段和方法。用偏光显微镜观察了猪骨ＥＣＭ胶原框架，以及注射性胶     

从NECM制取的可注射性胶原的生物学评价

从ＮＥＣＭ制取可注射胶原是从大分子降解为胶原分子，因此不需要交联剂和稳定剂。溶液中仅有胶原分子、无交联剂。本实验是将可注射胶原液注入大鼠尾部皮下组织内，共注射３０只，分三批杀死（１．５个月，３．０个月和半年），取注射部位的皮下组织作组织切片，染色（ＨＥ）、光镜观察（包括偏光显微镜）。     

动物皮肤、肌腱、软骨和骨的ECM制作

细胞外基质（ＥＣＭ）研究是组织工程学的重要部分，即是重要基础研究内容，又是研究细胞外基质的替代物课题。针对目前临床上大量应用人工合成的ＥＣＭ存在的问题（炎性反应、排斥反应、相容性等），本研究试图用动物的组织（自然的）ＥＣＭ替代人工合成的ＥＣＭ。用组织工程学方法处理动物组织，获得的产物经ＨＥ、奥新蓝染色、光镜观察和不染色切片偏光显微镜观察，证实经处理后的动物组织ＥＣＭ仅剩下肌腱、皮肤、软骨和骨的胶原框架。     

动物皮肤,肌腱,软骨和骨的ECM制作

细胞外基质研究是组织工程学的重要部分，即是重要基础研究内容，又是研究细胞外基质的替代物课题。针对目前临床上大量应用人工合成的ＥＣＭ存在的问题（炎性反应，排斥反应、相容性等），本研究试图用动物的组织（自然的）ＥＣＭ替代人工合成的ＥＣＭ。用组织工程学方法处理动物组织，获得的产物经ＨＥ、奥新蓝染色、光镜观察和不染色切片偏光显微镜观察，证实经处理后的动物ＥＣＭ仅剩下肌腱、皮肤、软骨和骨的胶原框架。     

从NECM制取的可注射性胶原的生物学评价

从ＮＥＣＭ制取可注射胶原是从大分子降解为胶原分子，因此不需要交联剂和稳定剂。溶液中仅有胶原分子，无交联剂。本实验是将可注射胶原液（１２０ｍｇ／ｍｌ）１ｍｌ注入大鼠尾部皮下组织内，共注射３０只，分三批杀死（１．５个月，３．０个月和半年），取注射部位的皮下组织作组织切片、染色（ＨＥ）、光镜观察（包括偏光显微镜）。发现三组在注射部位皮下组织内均有胶原分散存在。半年时胶原量少而且排列有序，未见包裹现象。除１．５个月少数动物皮下组织内有轻度炎性反应外，其余均未见到炎性反应。无排斥反应。局部组织无坏死现象。实验认为：本法所制可注射胶原液在半年内未发现特殊的生物学反应，胶原未完全吸收。     

动物NECM的稳定性评价

“动物ＮＥＣＭ的制作”文章发表近半年，已制作好的动物皮肤、肌腱、软骨和骨的ＮＥＣＭ已在保存液中保存了１３个月。为了观察ＮＥＣＭ和保存液的稳定性，本文做了如下几个方面的研究：①保存液：未放置ＮＥＣＭ新配制的和已放置１年的保存液；放置ＮＥＣＭ的保存液（１９９７年２月）。上述保存液均做细菌培养、镜下观察和成分分析。②电镜和组织学光镜观察：１９９７年２月制作的ＮＥＣＭ的光镜观察；放置１３个月后的ＮＥＣＭ电镜和光镜观察（包括偏光显微镜）；新鲜的正常相应组织的电镜和光镜观察。实验结果证明：猪皮肤和牛肌腱的ＮＥＣＭ已无细胞成分，基质为平行排列的胶原纤维丝或松散的胶原纤维网。而正常组织中细胞完整，胶原纤维呈致密交叉的网状编织结构。保存液清晰，无细菌生长，成分未变。     

从皮肤的细胞外基质（NECM）中制取可注射胶原

常规制取注射性胶原的方法是用酶降解法，经反复酸提、盐析、离心、交联等步骤，进行纯化，该法将胶原降解，酶提取分子片断，用交联剂组成可注射胶原。本法是从ＮＥＣＭ开始制取，ＮＥＣＭ已为胶原框架，因此步骤简化很多，仅需解裂胶原网状结构，酶解末端蛋白以消除特异性，最后降解成３００ｎｍ左右胶原。本法不用交联剂和稳定剂。生物原材料来源广泛，有利临床推广应用。经半年动物实验证明，本法制取的可注射胶原无排斥反应和炎     

从皮肤的细胞外基质(NECM)中制取可注射胶原

常规制取注射性胶原的方法是用酶降解法，经反复酸提、盐析、离心、交联等步骤，进行纯化，该法将胶原降解，酸提取分子片断，用交联剂组成可注射胶原。本法是从ＮＥＣＭ开始制取，ＮＥＣＭ已为胶原框架，因此步骤简化很多，仅需解裂胶原网状结构，酶解末端蛋白以消除特异性，最后降解成３００ｎｍ左右胶原。本法不用交联剂和稳定剂。生物原材料来源广泛，有利临床推广应用。经半年动物实验证明，本法制取的可注射胶原无排斥反应和炎性反应，也无包裹现象，半年时仍残留有部分胶原     

肾小球硬化及老年肾细胞外基质的变化研究

本文通过一侧肾切加重复阿霉素注射制作加速肾小球硬化大鼠模型，应用酶联免疫吸附试验（ＥＬＩＳＡ）对分离的肾小球内细胞外基质［胶原Ⅲ、胶原Ⅳ、层粘连蛋白（ＬＮ）和纤维连结蛋白（ＦＮ）］进行了硬化过程动态的定量研究，并将正常鼠（３月）和老年鼠（２６月）作了比较。结果显示，胶原Ⅲ在正常鼠肾小球内用ＥＬＪＳＡ方法未检测到；疾病所致的肾小球硬化过程胶原Ⅲ持续增加，弥漫性肾小球硬化期，较正常肾增加１１．８倍。胶原Ⅳ、ＬＮ和ＦＮ为正常肾小球内存在的细胞外基质（ＥＣＭ），在肾小球硬化的早、中期明显增加；弥漫性肾小球硬化期分别为正常肾的１２．３、１６．３和５．１倍。老年鼠与正常鼠相比，胶原Ⅲ无显著性变化（Ｐ＞０．０５），胶原Ⅳ、ＬＮ和ＦＮ分别为正常鼠的９．１、１０．０和２．８倍。本研究证实，ＥＣＭ的积聚是肾小球硬化过程中重要的病理特征，胶原Ⅲ（一种间质胶原）似与疾病所致的肾小球硬化发展有更密切和直接的关系。     

肾病患儿免疫细胞对肾小球上皮细胞合成基质的影响

目的为了明确免疫细胞对肾小球上皮细胞（ｇｌｏｍｅｒｕｌａｒｅｐｉｔｈｅｌｉａｌｃｅｌＧＥＣ）合成功能的直接作用。方法应用肾小球细胞体外培养，同位素掺入及放射免疫技术，以总胶原，层粘连蛋白，Ⅲ型前胶原及Ⅳ型胶原的合成为观察指标，动态研究了不同病理类型原发性肾病综合征（ＩＮＳ）患儿外周血单个核细胞（ｐｅｒｉｐｈｅｒａｌｂｌｏｏｄｍｏｎｏｎｕｃｌｅａｒｃｅｌＰＢＭＣ）对ＧＥＣ生物功能的影响。结果（１）肾病极期未经激素治疗组（未治组）ＰＢＭＣ上清明显促进了ＧＥＣ合成层粘连蛋白；（２）未治ＰＢＭＣ上清抑制了ＧＥＣ合成总胶原；（３）未治组ＰＢＭＣ上清促进了Ⅲ型前胶原的合成，而对Ⅳ型胶原的合成无明显影响；（４）肾病患儿ＰＢＭＣ的上述作用与是否足量激素治疗有关，而与尿蛋白能否阴转、肾组织病理类型、肾病临床类型等无直线相关关系。结论原发性肾病患儿循环免疫细胞可影响ＧＥＣ合成细胞外基质的功能。免疫细胞的这种活性可被激素治疗改变。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

Intraoperative autotransfusion is associated with modest reduction of allogeneic transfusion in prosthetic hip surgery

Background: The efficacy of intraoperative salvage and washing of wound blood and the predictors of allogeneic red cell transfusions in prosthetic hip surgery are insufficiently known.
Methods: In 96 patients, undergoing primary or revision surgery, salvaged and washed red cells and, if necessary, allogeneic blood were used to keep haematocrit not lower than 33%. The bleeding of red cells during hospital stay was calculated from the red cell balance. The preoperative red cell reserve (millilitres of red cells in excess of a haematocrit of 33%) was estimated and the difference between this volume and the total bleeding of red cells was retrospectively used to classify patients with regard to the need for red cells. Stepwise regression analysis was used to define patient-related variables associated with allogeneic blood transfusion.
Results: Preoperative knowledge of the type of operation (primary, revision), the preoperative red cell reserve, and the body mass could predict roughly half of the need for banked blood (r²=0.45). Only one-third of the total bleeding of red cells was retransfused. For complete avoidance of allogeneic blood, autotransfusion was most effective in patients with a moderate need (0–4 u). However, 32% of such patients required allogeneic blood.
Conclusions: Autotransfusion has a limited efficacy to decrease the need for allogeneic blood, and other blood-saving methods should be added for this purpose. It is difficult to predict the need for allogeneic blood preoperatively.     

缺氧对肾小管上皮细胞分泌外泌体的影响

目的    观察缺氧对肾小管上皮细胞分泌外泌体的影响,探讨外泌体在缺氧致肾脏损伤中的作用及机制。 方法    （1）常氧（21% O₂）及缺氧（1% O₂）分别处理大鼠肾小管上皮细胞（NRK-52E）48 h,收集细胞上清液并使用高速梯度离心法分离外泌体。采用透射电镜、纳米示踪分析、Western印迹、蛋白浓度定量鉴定并比较两组外泌体的基本特性。（2）在共培养实验中,以不同浓度（1、10、50、100、300 mg/L）的常氧外泌体、缺氧外泌体分别干预脂多糖（LPS）诱导的大鼠原代腹腔巨噬细胞,使用实时荧光定量PCR与酶联免疫吸附试验（ELISA）法分别检测巨噬细胞白细胞介素6（IL-6）、肿瘤坏死因子α（TNF-α）、诱导型氮氧化物合酶（iNOS）水平;使用Western印迹法检测巨噬细胞磷酸化（p）STAT/STAT及细胞因子信号传导抑制蛋白1（SOCS1）的蛋白表达;最后,使用实时荧光定量PCR法检测常氧外泌体与缺氧外泌体中炎性反应相关微RNA（microRNA,miR）的表达差异。 结果    （1）离心得到的囊泡具有外泌体典型的结构,粒径小于150 nm,表达外泌体标志蛋白CD63,说明分离得到外泌体。缺氧对肾小管上皮细胞分泌的外泌体形态、粒径分布比例无明显影响,但提高了外泌体的分泌量。（2）缺氧外泌体相比于常氧外泌体促进了LPS诱导的M1型巨噬细胞IL-6、TNF-α、iNOS 的表达和分泌（均P＜0.01）,同时提高STAT的磷酸化水平并减少SOCS1的蛋白表达（均P＜0.01）;对炎性反应相关microRNA检测发现缺氧外泌体中miR-155、miR-27a表达量较常氧外泌体明显升高（P＜0.05）。 结论    缺氧可改变外泌体的生物学功能,表现为协同促进LPS诱导的M1型巨噬细胞的表型转化,这可能是慢性肾脏病微炎性反应状态持续的原因之一。     

In Vitro Function and Durability Assessment of a Novel Polyurethane Heart Valve Prosthesis

Abstract While flexible-leaflet, central-flow prosthetic heart valves promise relief from anticoagulation therapy, they continue to be restricted by inadequate durability. In consequence, a novel trileaflet valve, made entirely from polyurethane, has been developed. A batch of 6 consecutively manufactured polyurethane valves was subjected to hydrodynamic function and accelerated fatigue testing. Computerized data acquisition and control systems have been introduced to improve valve testing methodologies. In terms of hydrodynamic function, the polyurethane valve demonstrates transvalvular pressure gradients similar to those for a bioprosthetic valve (Carpentier-Edwards) and levels of retrograde flow significantly less than those for either the bioprosthetic valve or a bileaflet mechanical valve (St Jude Medical). The equivalent of 10 years of cycling without failure has been exceeded by all 6 polyurethane valves in accelerated fatigue tests with 2 valves remaining intact after 674 million cycles (equivalent to approximately 17 years) in continuing tests. Highspeed photography revealed considerable differences in leaflet motion between valves cycled at accelerated and physiological rates.     

Negative pressure ventilation vs. spontaneous assisted ventilation during rigid bronchoscopy: A controlled randomised trial

Background: Ventilation during interventional rigid bronchoscopy (IRB) under general anaesthesia (jet ventilation, positive pressure ventilation and spontaneous assisted ventilation) may offer some difficulties. This study compares the effectiveness during IRB of intermittent negative pressure ventilation (INPV) and spontaneous assisted ventilation (SAV). Methods: Thirty-eight patients submitted to IRB were randomised into two groups: SAV or INPV. All patients received a total intravenous anaesthesia; INPV patients were paralysed. Pre-and intra-operative arterial blood gases and O₂ flow through a rigid bronchoscope were assessed. The endoscopist applying a subjective score evaluated the operating conditions. Results: Patients of the INPV group, as compared to the SAV group, required a lower dosage of fentanyl (2.6 ± 1.8 (μg · kg^?1· h^?1 vs. 6.6 ± 4.8 μg · kg^?1· h^?1), a lower O₂ supply (3.3 ± 2.8 1/min vs. 11.6 ± 3.4 1/min), a shorter recovery time (5.4 ± 2.9 min vs. 9.8 ± 7.1 min) and no manually assisted ventilation (0 ± 0 vs. 1 ± 1.1 nd?/procedure). Intraoperative PaCO₂ was higher in the SAV (8.1 ± 1.3 kPa) than in the INPV group (5.0 ± 1.6 kPa) and intraoperative pH differed in the two groups (7.26 ± 0.05, SAV vs. 7.47 ± 0.08, INPV). Operating conditions, as assessed by a subjective score, were considered better with INPV than with SAV (4.9 vs. 4.3). Conclusions: As compared to SAV, INPV in paralysed patients during IRB reduces administration of opioids, shortens recovery time, prevents respiratory acidosis, excludes the need for manually assisted ventilation, reduces 02 need and affords optimal surgical conditions. INPV appears a safe, non-invasive and effective ventilatory management during IRB.