大鼠骨骺干细胞的分离鉴定及其永生化细胞株的构建

[目的]分离、鉴定大鼠骨骺干细胞并建立永生化的大鼠骨骺干细胞株,为细胞移植和转基因治疗提供稳定的细胞来源.[方法]采用Percoll不连续密度梯度离心法分离骨骺干细胞,利用电穿孔转染技术将含有猿肾病毒40大T抗原基因（SV40Tag）的质粒pCMVSV40T/PUR转染骨骺干细胞,经嘌呤霉素筛选,抗性克隆扩大培养.应用FGFR-3抗体和PCNA抗体进行免疫细胞化学染色,观察细胞的形态及其生长状况并绘制细胞生长曲线.用免疫细胞化学法和RT-PCR检测SV40Tag在转染细胞中的表达.[结果]转染后获得一个阳性细胞克隆,免疫细胞化学结果显示FGFR-3抗体染色阳性.SV40Tag抗体染色和RT-PCR结果显示SV40Tag已稳定转染入骨骺干细胞.转染细胞经扩大培养,命名为永生化骨骺干细胞.[结论]成功纯化大鼠骨骺干细胞并构建了SV40Tag永生化的骨骺干细胞株.     

猿肾病毒40大T抗原基因永生化大鼠神经前体细胞株的构建

目的建立猿肾病毒40大T抗原基因(SV40Tag)永生化大鼠神经前体细胞株,为细胞移植治疗和转基因治疗提供稳定的细胞来源。方法利用脂质体介导的基因转染技术将含有SV40Tag的质粒pCMVSV40T/PUR转染原代培养的新生大鼠神经前体细胞,经嘌呤霉素筛选,阳性克隆扩大培养并连续传代。应用巢蛋白抗体进行细胞鉴定,5%胎牛血清诱导细胞分化后,应用免疫细胞化学法检测其分化能力,观察细胞的形态及其生长状况,绘制细胞生长曲线。用RT-PCR、Southern印迹杂交和免疫细胞化学法检测SV40Tag在转染细胞中的表达。结果转染细胞经筛选培养后获得1 个阳性细胞克隆,免疫细胞化学结果显示细胞的巢蛋白和微管相关蛋白2染色为阳性,增殖能力较强。5%胎牛血清可诱导转染细胞分化为微管相关蛋白2阳性和胶质纤维酸性蛋白阳性细胞。Southern印迹杂交结果显示转染细胞基因组中存在SV40Tag cDNA,并可检测到SV40Tag mRNA及其蛋白的表达。转染细胞经扩大培养,命名为永生化神经前体细胞。贴壁培养的神经前体细胞,群体倍增时间为(22.9±2.7)h,传代、冻存和复苏对细胞形态及生长无明显影响。结论成功地构建了SV40Tag永生化的大鼠神经前体细胞株。     

猿肾病毒40介导的人前软骨干细胞永生化的实验研究

目的 构建猿肾病毒40大T抗原基因(SV40Tag)介导的永生化人前软骨干细胞株,为下一步基因打靶研究其分化分子机制提供稳定的细胞来源. 方法采用脂质体介导的基因转染技术将含有SVd0Tag的质粒pCMVSV40T/PUR转染人前软骨干细胞(PSCs),经嘌呤霉素筛选,阳性克隆扩大培养并连续传代.用免疫组化、RT-PCR、Southern印迹杂交法对转染细胞进行鉴定,并检测SV40Tag在转染细胞中的表达及其与基因组的整合情况. 结果 筛选获得的阳性克隆扩大培养,命名为永生化前软骨干细胞(IPSCs),能连续传代培养,细胞生长迅速.免疫组化和RT-PCR证实IPSCs成纤维生长因子受体-3阳性,并可检测到SV40Tag mRNA及其蛋白的表达.Southern印迹杂交显示IPSCs基因组中存在SV40Tag cDNA. 结论 成功构建了SV40Tag介导的永生化人前软骨干细胞株.     

猿肾病毒40大T抗原基因永生化大鼠星形胶质细胞株的构建

目的 构建永生化大鼠星形胶质细胞，为转基因细胞移植镇痛提供细胞载体。方法 采用差速粘附法体外分离和培养大鼠大脑皮层星形胶质细胞。利用脂质体将含有猿肾病毒40大T抗原(SV40Tag)基因的质粒pCMVSV40T／PUR转染培养的大鼠星形胶质细胞。经嘌呤霉素1．5μg／ml筛选后，挑选阳性细胞克隆扩大培养并连续传代。PCR、RT-PCR及免疫组化检测阳性细胞克隆中SV40Tag基因的整合情况及其表达，并对传代细胞的胶质原纤维酸性蛋白(GFAP)进行检测。结果 成功获得体外培养的大鼠星形胶质细胞，GFAP阳性表达；筛选获得阳性细胞克隆，连续传代培养近50代；PCR、RT-PCR产物经1．5％琼脂糖凝胶电泳分析显示558bp处有一特异性扩增条带，与阳性对照条带相同，而未转染pCMVSV40T／PUR的细胞无扩增条带，回收片段经测序、比对与SV40Tag的基因序列一致(100％)；同时转染的阳性细胞克隆SV40Tag和GFAP免疫染色阳性。结论 成功地构建了SV40Tag基因永生化的大鼠星形胶质细胞株。     

转导人端粒酶逆转录酶基因致人骨髓间充质干细胞永生化并向软骨细胞诱导分化的研究

目的 建立永生化人骨髓间充质干细胞系并向软骨细胞诱导分化,以供软骨组织工程基础研究及临床应用.方法 原代培养人骨髓间充质干细胞(hMSC),用含有人端粒酶逆转录酶(hTERT)基因的逆转录病毒转染hMSC,G418筛选得到阳性克隆,体外连续培养,检测端粒酶的表达及活性.TGF-β1和地塞米松对转化后的hMSC-hTERT细胞诱导,使其向软骨细胞分化,并用原位杂交和免疫组化检测II型胶原.结果 外源性hTERT在转染细胞中稳定表达并传至第50代,永生化的hMSC细胞经TGF-β1和地塞米松诱导在体外分化为软骨细胞.结论 外源性hTERT基因可以有效地在体外使hMSC永生化,永生化的hMSC细胞经诱导可在体外分化为软骨细胞,从而作为软骨组织工程研究的细胞来源.     

破骨细胞转基因永生化问题的初步探讨

目的：通过转基因技术建立破骨细胞永生化细胞系，方法：经1，25（OH）2D3诱导，获得小鼠骨髓来源的破骨前体细胞，脂质体法（Fugene6）将猿猴病毒40（SV40）和绿色荧光蛋白（GFP）质粒分别转染入破抽前体细胞，G418筛选抗性克隆；同时将GFP转染入逆转录病毒包装细胞（P167）中，作为方法对照，继而，用含有GFP的逆转录病毒感染破骨前体细胞，G418筛选抗性克隆。结果：获得小鼠骨髓来源的破骨前体细胞，Fugene6转染SV40和GFP到破骨前体细胞后，G418筛选未获得阳性克隆，但GFP转染PT67细胞获得阳性克隆和含有GFP的逆转录病毒。将含有GFP的逆转录病毒感染破骨前体细胞，G418筛选未获得阳性克隆，结论：通过破骨细胞转基因永生化，建立破骨或破骨前体系细胞系的方法是一个非常有意义的研究课题，但是难度较大。可以初步认为：脂质体和逆转录病毒载体的方法不是破骨细胞转基因的最佳方法。     

Sox9基因真核表达载体的构建及其诱导大鼠骨髓基质细胞定向分化为骨骺干细胞

[目的] 从永生化骨骺干细胞中克隆Sox9基因并构建真核表达载体,并探讨Sox9诱导骨髓基质细胞向骨骺干细胞分化的可能性.[方法]以RT-PCR方法获得Sox9全长,插入pGEM-T Easy克隆载体中,测序正确后与pEGFP-IRES2表达载体酶切后连接,复合质粒以脂质体法转染骨髓基质细胞,观察转染效率,Sox9和 FGFR-3的表达.流式细胞术鉴定细胞表型,MTT法检测细胞增殖活性.[结果]成功的完成了Sox9的扩增和表达载体的构建 ,重组载体转染骨髓基质细胞后能检测到Sox9、FGFR-3的表达,增殖活性与骨骺干细胞无异.[结论]成功构建了Sox9真核表达载体,其能诱导骨髓基质细胞分化为骨骺干细胞并具有其特性.     

大鼠蛛网膜下腔移植超顺磁性氧化铁纳米离子标记永生化神经前体细胞后的磁共振成像追踪

目的观察大鼠蛛网膜下腔移植超顺磁性氧化铁纳米粒子（SPIO）标记永生化神经前体细胞后的磁共振成像追踪。方法用SPIO-多聚赖氨酸复合物（SPIO-PLL）标记永生化神经前体细胞。采用普鲁士蓝染色鉴定SPIO-PLL标记永生化神经前体细胞的效率，采用MTT法检测标记前后细胞活力，用免疫细胞化学法对标记后1周的细胞进行抗巢蛋白、微管相关蛋白和胶质纤维酸性蛋白（GFAP）染色，检测标记细胞的分化能力。蛛网膜下腔置管成功的SD大鼠10只，随机分为2组（n=5），标记细胞组和未标记细胞组，蛛网膜下腔分别移植标记后2d的永生化神经前体细胞和未标记细胞，移植后30min及移植后1周用MRI对蛛网膜下腔的细胞进行活体追踪，用组织切片进行普鲁士蓝染色和抗猿肾病毒40大T抗原染色。结果SPIO可以高效率地标记永生化神经前体细胞，普鲁士蓝染色显示SPIO—PLL标记永生化神经前体细胞质内出现细小的天蓝色铁颗粒，SPIO-PLL标记对永生化神经前体细胞的活力没有明显的影响，标记后1周，抗巢蛋白、微管相关蛋白染色阳性，GFAP染色阴性。标记细胞组移植后30min及移植后1周MRI活体检查发现标记细胞在磁共振成像上呈明显的低信号改变，脊髓组织学切片结果普鲁士蓝、抗猿肾病毒40大T抗原染色阳性；未标记细胞组磁共振成像上无明显低信号改变。结论利用MRI技术可以对蛛网膜下腔移植后的标记细胞进行活体追踪。     

生长分化因子5基因转染诱导骨髓基质干细胞分化的研究

目的 探讨人生长分化因子5(GDF5)基因转染对骨髓基质干细胞(BMSCs)生长及分化的影响.方法 采用脂质体介导法将GDF5基因导人人BMSCs,通过MTT法和流式细胞仪分别检测细胞增殖能力和细胞周期,在光镜和电镜水平观察细胞形态,用逆转录多聚酶链反应(RT-PCR)和免疫细胞化学方法榆测GDF5和Ⅱ型胶原mRNA和蛋白质的表达.柠檬酸铅法检测细胞碱性磷酸酶活性,RT-PCR法检测骨钙素mRNA表达.结果 GDF5在转染细胞内得到稳定表达,转染细胞的增殖能力和细胞周期与未转染细胞基本一致.光镜下转染细胞中多角形细胞相对增多,排列方式不规则.电镜下转染细胞核呈不规则形,细胞器丰富.转染细胞Ⅱ型胶原mRNA和蛋白表达阳性,骨钙素mRNA表达阴性.结论 GDF5基因脂质体法转染BMSCs成功,转染细胞仍保持正常生长增殖特性.GDF5可诱导BMSCs向软骨表型分化,GDF5基因修饰的BMSCs可作为软骨组织上程的候选种子细胞.     

软骨前体细胞的分离鉴定及IL-1β对其成软骨分化的影响

目的对正常软骨中的软骨前体细胞进行分离、鉴定,并对不同浓度IL-1β对软骨前体细胞的成软骨分化影响进行研究。方法取正常成年新西兰大白兔的软骨细胞,通过纤连蛋白粘连分离出软骨前体细胞,采用流式细胞仪对其细胞表型进行鉴定,倒置相差显微镜观察其克隆增殖,并行成骨、成脂、成软骨三系分化观察。培养软骨前体细胞团并分为4组,分别加入普通H-DMEM培养基(A组)、成软骨诱导分化培养基(B组)、成软骨诱导分化培养基+0.1 ng/mL IL-1β(C组)、成软骨诱导分化培养基+1.0 ng/mL IL-1β(D组),培养3周行组织学、生物化学、实时荧光定量PCR等检测,观察IL-1β的影响。结果在正常软骨细胞中存在软骨前体细胞,经鉴定有干细胞表型阳性表达,有与干细胞相似的克隆增殖能力及分化能力。HE染色示,C、D组中细胞团块较B组明显减小,细胞呈肥大样改变。番红O、Ⅱ型胶原及Ⅹ型胶原染色示,B组较A组染色深,C、D组均浅于B组,D组浅于C组。生物化学成分测定示,C、D组的总胶原、糖胺聚糖(glycosaminoglycan,GAG)相对含量及GAG/DNA比值均显著低于B组,D组显著低于C组,差异均有统计学意义(P0.05);C、D组DNA相对含量均显著高于B组(P0.05),但C、D组间差异无统计学意义(P0.05)。实时荧光定量PCR检测示,C、D组Ⅱ型胶原、Ⅹ型胶原、Sox-9 mRNA相对表达量均显著低于B组,D组显著低于C组,差异均有统计学意义(P0.05);而C、D组Runx-2和MMP-13mRNA相对表达量均显著高于B组,D组显著高于C组,差异均有统计学意义(P0.05)。结论在正常软骨组织中存在一种有干细胞特性的软骨前体细胞,其有克隆和潜在分化的能力。IL-1β对软骨前体细胞成软骨分化有抑制作用,并有促进成骨分化的可能。     

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.