羟喜树碱和环孢素A对异基因大鼠心脏移植物急性排斥反应的协同抑制作用

目的 探讨羟喜树碱（OPT）和环孢素A（CsA）对异基因心脏移植物急性排斥反应的协同抑制作用。方法 以纯系SD大鼠为供者,纯系Wistar大鼠为受者,行异体颈部异位心脏移植。40只受者大鼠心脏移植后随机分成4组。A组接受安慰剂。B组接受 OPT1.0mg·kg-1·d-1,腹腔注射。E组接受CsA　10mg·kg-1·d-1,导管灌胃。F组联合应用OPT和CsA,方法剂量同B、E组。结果A组平均存活期为（6.05±0.76）d,B组为（11.45±1.99）d,E组为（14.45±4.85）d,F组有5只大鼠平均存活期为（45.00±19.43）d,另5只大鼠在移植60d后停用OPT和 CsA,存活期超过730 d,并经试验证明形成特异性免疫耐受。结论OPT和CsA的联合应用显著降低异基因大鼠心脏移植物急性排斥反应,明显延长心脏移植存活期。     

10-羟基喜树碱对异基因大鼠心脏移植物急性排斥反应的抑制作用

目的　探讨 10 羟基喜树碱 (HCPT)对移植物急性排斥反应的免疫抑制作用。方法　以SD大鼠为供者 ,Wistar大鼠为受者 ,行大鼠同种异体异位心脏移植。用中药制剂 10 羟基喜树碱(HCPT)预防和治疗移植物急性排斥反应。结果　HCPT 1.0mg·kg-1·d-1组与对照组比较 ,移植物存活时间明显延长 (6.0 5d/ 11.45d ,P <0 .0 0 1) ;HCPT 2 .0mg·kg-1·d-1组作用更为显著 (>2 41.6d) ,其中 3只大鼠于术后 60d停用HCPT ,移植心脏长期存活 ,超过 73 0d ,并经证实已形成免疫耐受。大鼠心脏移植物发生急性排斥反应时 ,HCPT 10 .0mg·kg-1·d-1能使排斥反应完全逆转 ,移植心脏功能完全恢复正常。较大剂量HCPT可导致轻微的胃肠道反应 ,但未观察到明显的肝、肾、心、脾、睾丸和造血系统损害。结论　HCPT对大鼠移植心脏急性排斥反应具有显著的抑制作用 ,且具有剂量相关性     

雷公藤多甙及环孢素A在大鼠心脏移植中的协同作用

目的探讨心脏移植术后单用雷公藤多甙(TWHF)及与环孢素A(GsA)合用对大鼠心脏移植物生存期的影响.方法供体为雄性PVG(RT1C)大鼠,受体为雄性Lewis(LEW;RT11)大鼠.采用改良的Ono和Lindsey方法实施腹部异位心脏移植.根据术后处理不同将实验动物分为4组第1组(5只)对照组(非治疗组);第2组(7只)TWHF 60 mg·kg-1·d-1;第3组(6只)CsA 15 mg·kg-1·d-1;第4组(5只)TWHF 40 mg·kg-1·d-1+CsA1 mg·kg-1·d-1.用吐温80及蒸馏水将TWHF配制成1%悬液;CsA使用前以注射用水配成5g/L.术后当天即给药,TWHF为灌服,CsA为肌肉注射.直至发生排斥反应或最多给药14 d.每天通过触摸监测移植心脏的功能.结果4组移植大鼠心脏平均存活8.8、12.0、17.0、34.6 d.结论心脏移植术后给予雷公藤多甙及CsA联合治疗,能明显延长移植心脏的功能存活时间.     

茯苓醇提取物抗心脏移植急性排斥反应的实验研究

目的　研究茯苓醇提取物对心脏移植急性排斥反应的抑制作用。方法　以Wistar大鼠为供者、SD大鼠为受者 ,建立异位 (腹腔 )心脏移植模型 ,移植前按组分别以橄榄油、茯苓醇提取物及环孢素A灌胃 ,并设SD大鼠空白对照组。术后观察移植心的存活时间 ,测定各组术后第 7d外周血中白细胞介素 2 (IL 2 )和γ干扰素 (IFN γ)含量以及CD3+、CD4 +、CD8+细胞和CD4 +细胞与CD8+细胞的比值 (CD4 +/CD8+) ,并观察移植心的病理变化。结果　接受茯苓醇提取物 2 5mg·kg-1·d-1或 5 0mg·kg-1·d-1灌胃的大鼠 ,移植心存活时间显著延长 ,病理损害程度减轻 ,外周血IL 2及IFN γ的含量以及CD3+、CD4 +、CD8+细胞百分比和CD4 +/CD8+比值降低 ,与环孢素A 5mg·kg-1·d-1灌胃的结果相当。结论　茯苓醇提取物对心脏移植急性排斥反应具有明显的抑制作用。     

雷帕霉素对环孢素A诱导的慢性肾毒性的影响

目的　了解雷帕霉素 (RPM)对环孢素A(CsA)诱导的慢性肾毒性的影响。方法　对进低盐饮食的大鼠给予RPM与CsA溶剂、RPM (0 .5mg·kg-1·d-1与 1mg·kg-1·d-1)、CsA (4mg·kg-1·d-1与 8mg·kg-1·d-1)以及两者联用 ,均用药 2 8d。结果　接受RPM 1mg·kg-1·d-1的大鼠血糖明显升高 ,加重CsA(4mg·kg-1·d-1)诱导的慢性肾毒性作用 ;而亚治疗剂量的RPM (0 .5mg·kg-1·d-1)与CsA(4mg·kg-1·d-1)联用只引起轻度的血糖上升及肾小管细胞受损与间质纤维化 ,与前者相比 ,P <0 .0 5。治疗剂量的RPM(1mg·kg-1·d-1)与CsA(8mg·kg-1·d-1)联用则导致更为显著的肾功能受损、结构改变与高糖血症。结论　亚治疗剂量的RPM与CsA的联用可协同产生慢性肾毒性作用     

AG490延长移植心存活时间的探讨

目的 研究AG490在大鼠心脏移植中免疫抑制及延长移植心存活时间的作用,探讨AG490的作用机制.方法 供者为SD大鼠,受者为Wistar大鼠,建立大鼠心脏移植模型.将受者分为4组.对照组(14只):术后1～7 d经尾静脉注射生理盐水0.2 ml·kg-1·d-1;AG490组(14只):术后1～7 d经尾静脉注射AG490 20 mg·kg-1·d-1;CsA组(10只):术后1～7 d经尾静脉注射CsA20 mg·kg-1·d-1;AG490+CsA组(10只):术后1～7 d经尾静脉注射AG490和CsA各20mg·kg-1·d-1.术后各组分别取10只受者,观察移植心存活时间,并在术后1、4和7 d时,检测受者外周血中白细胞介素(IL)-2和IL-6的水平.术后第7天,处死对照组和AG490组受者(各4只)后,分别取移植心组织进行病理学检测.结果 AG490组受者术后移植心存活时间为(26.6±3.81)d,CsA组为(28.4±4.25)d,AG490+CsA组为(31.8±4.39)d,均较对照组的(8.4±0.84)d显著延长(P＜0.05).与对照组相比,AG490组术后外周血IL-2水平显著降低(P＜0.05),IL-6水平虽有所降低,但差异无统计学意义(P＞0.05),而AG490+CsA组IL-2和IL-6水平下降更为显著,与对照组相比,差异均有统计学意义(P＜0.05).AG490组移植心组织中淋巴细胞浸润程度较对照组明显减轻.结论 AG490具有免疫抑制作用,能延长移植物的存活时间,与CsA联合应用时效果更加明显.AG490的主要作用机制包括降低IL-2表达的水平,抑制移植心组织中淋巴细胞的浸润.     

延长大鼠异种心脏移植后存活时间的实验研究

目的　研究如何延长大鼠异种心脏移植后的存活时间。方法　实验分为A、B、C、D四组。A组 :移植术前 12、8、4、0d及 10、6、2、0d分别将脾细胞 1× 10 8个 ,抗血清 0 .2ml静脉注入受体大鼠 ;B组 :在A组的基础上 ,加用中华眼镜蛇毒 (CCV) 0 .2mg·kg-1·d-1,术前 3d至术日腹腔注射。C组 :在B组的基础上 ,加用环孢素A(CsA) 10mg·kg-1·d-1、环磷酰胺 (Cy) 2 0mg·kg-1·d-1,术前 12d开始至术日腹腔注射。D组 :在C组的基础上 ,加用抗巨噬细胞和抗自然杀伤细胞单克隆抗体 2 5 0 μg·kg-1·d-1,术前 12d开始至术日腹腔注射。结果　A、B、C、D四组移植心脏分别存活 (0 .32± 0 .12 )h ,(2 5 .6± 9.6 )h、(48.6± 10 .4)h和 (72 .4± 2 1.7)h ;术日各组IgG均下降 ,尤以C、D组下降明显 ,与A、B组比较 ,差异有显著性 (P <0 .0 5 )。结论　术前静脉注射供体脾细胞及抗血清 ,尤其与CCV、CsA、Cy合用 ,能显著抑制IgG的产生 ,延长移植心脏的存活时间。     

门静脉预输注供者凋亡骨髓细胞延长大鼠移植心脏的存活时间

目的探讨门静脉输注供者的凋亡骨髓细胞对大鼠移植心脏存活时间的影响。方法以Wistar大鼠为供者、SD大鼠为受者,将其随机分为4组,每组15只,A组为对照组,受者术前6d经门静脉输注RPMI1640培养基0.5ml,术后不注射环孢素A(CsA);B组为骨髓细胞输注组,受者术前6d经门静脉输注供者的骨髓细胞5×107个,术后不用CsA;C组为凋亡细胞输注组,受者术前6d经门静脉输注供者的凋亡骨髓细胞5×107个,术后不用CsA;D组为CsA组,受者术前3d起腹腔注射CsA5mg/kg,直至术后10d。60Coγ射线照射诱导骨髓细胞凋亡,各组大鼠建立腹部异位心脏移植模型。观察各组移植心的存活时间、组织病理学改变,测定受者血清中白细胞介素10(IL-10)及转化生长因子β1(TGF-β1)的含量及单向混合淋巴细胞培养(MLR)结果。结果C组移植心的存活时间为(14.00±0.95)d,较A组明显延长(P<0.01),但仍未达到长期存活(存活时间短于CsA组)。术后7d,C组移植心组织切片呈现中度急性排斥反应,心肌细胞损害不明显,但有大量淋巴细胞浸润。除术后7d的TGF-β1外,C组其它各测定时点的血清IL-10及TGF-β1均高于其它3个组。C组大鼠的脾细胞在供鼠脾细胞的刺激下,细胞增殖反应明显低于A组、B组(P<0.01),而对第三品系大鼠的脾细胞仍有较强的增殖反应,具有明显的抗原特异性;CsA组的细胞增殖均被抑制。结论门静脉预输注供者的凋亡骨髓细胞,可明显延长大鼠移植心脏的存活时间,但单纯单剂量的输注凋亡细胞并不足以建立长期、稳定的免疫耐受。     

术前使用FTY720诱导小鼠对同种异体心脏移植物的耐受

目的　观察术前使用FTY72 0对小鼠同种异体心脏移植物存活时间的影响。方法　以小鼠颈部异位心脏移植为模型 ,供者为BALB/c小鼠 ,受者为C57BL/ 6小鼠。受鼠分为 4组 :A组为空白对照组 ;B组术前 3d至术后 1 1d每日管饲FTY72 0 ;C组手术当天至术后 1 4d每日管饲FTY72 0 ;D组仅在术前 3d至手术当天每日管饲FTY72 0。FTY72 0的剂量都为 3mg·kg- 1 ·d- 1 。结果　A组移植物中位存活时间 (MST)为 8d ;B组所有移植物存活时间均超过 2 7d ,有半数 (6/ 1 1 )移植物存活超过1 0 0d ;C组移植物存活时间显著延长 (MST =1 6d) ;D组移植物中位存活时间为 1 4d ,并有 1只超过1 0 0d。结论　术前使用FTY72 0可以延长同种异体心脏移植物的存活时间 ,诱导受者对同种异体心脏移植物的耐受     

急性排斥反应过程中淋巴细胞趋化因子基因表达的意义

目的　探讨急性排斥反应过程中淋巴细胞趋化因子 (LTN)mRNA在移植心脏局部表达的意义及环孢素A(CsA)对其的影响。方法　以SD大鼠为受者 ,Wistar大鼠为供者 ,施行异位 (腹腔 )心脏移植术 ,分为术后使用CsA组 (15mg·kg-1·d-1)和不用组 ,并设SD大鼠间的心脏移植组 (同系移植组 ) ,以正常SD大鼠为对照组。采用一步法逆转录 聚合酶链反应 (RT PCR)检测术后不同时间移植心脏局部LTNmRNA的表达。结果　正常对照组和同系移植组在各时间点均未见LTNmRNA表达 ;LTNmRNA在未用CsA组的表达变化与急性排斥反应的进程相关 ,排斥反应的早期出现LTNmRNA表达上调 ,术后 5d时达到峰值 ,而应用CsA组 ,LTNmRNA的表达峰值出现延缓 ,且明显低于未用CsA组 (P <0 .0 5 )。结论　LTNmRNA的表达上调与排斥反应过程中淋巴细胞浸润密切相关 ,可能对急性排斥反应的早期诊断有帮助 ;CsA可抑制LTN基因的表达 ,可能是其免疫抑制作用的又一分子免疫学机制     

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.