心脏缺血预适应对中性粒细胞功能与活性氧释放的影响

目的:观察缺血预适应中中性粒细胞黏附、浸润及活性氧释放的特点,旨在探讨预适应保护效应与白细胞功能及活性氧的关系。方法:①实验于2000-06/2001-12在解放军广州军区广州总医院医学实验科及南方医科大学南方医院心内科实验室完成。选用杂种犬12条,雄性7条,雌性5条。②麻醉后,开胸游离前降支冠状动脉,稳定30min,造成心肌缺血模型。造模后将犬随机分为2组:缺血再灌注组(n=6),缺血1h后再灌注2h;缺血预适应组(6条),在缺血1h前给予血流阻断5min,灌注5min,反复4次,然后缺血1h,再灌注2h。③分别于基础(缺血和再灌注之前)、缺血1h、再灌注2h各时间点,采用流式细胞术测定中性粒细胞CD11b/CD18表达,按梗死面积%=梗死区面积/危险区面积×100%公式计算心肌梗死范围。按南京聚力生物医学工程提供试剂盒说明测定血清丙二醛水平和超氧化物歧化酶活性。计算髓过氧化物酶活力(kU/g)=ΔA460/(12×组织酶量/3),ΔA460为460nm处吸光度1min增大的值,3为反应的总体积,12为Sigma公司规定的每毫升1mg邻联茴香胺的吸光度;组织酶量指每0.1mL所用酶液中含酶的量。④两组间比较用配对t检验,多组间比较用方差分析,多组间两两比较用SNK方法。结果:犬12条均进入结果分析。①心肌梗死范围:缺血预适应组明显小于缺血再灌注组(P<0.01)。②中性粒细胞膜CD11/CD18表达:缺血再灌注组缺血1h、再灌注2h明显高于基础和缺血预适应组(P<0.05～0.01)。③髓过氧化物酶活性:缺血预适应组缺血和坏死心肌明显低于缺血再灌注组(P<0.05),两组缺血和坏死心肌明显高于正常心肌(P<0.05)。缺血预适应组正常心肌组织低于缺血再灌注组,但差异不明显(P=0.11)。血清丙二醛水平:缺血再灌注组缺血1h和再灌注2h明显高于基础和缺血预适应组(P<0.05)。血清超氧化物岐化酶活性:缺血1h缺血再灌注组明显低于基础和缺血预适应组(P<0.05)。再灌注2h虽然也有此变化,但差异不明显(P>0.05)。结论:缺血预适应能阻抑缺血再灌注所致的中性粒细胞黏附、浸润及活性氧的损害,这可能是发挥缺血预适应保护的重要作用之一。     

冠心病Warm-up现象与缺血预适应

对心脏而言,反复缺血刺激可导致其对随后发生再次缺血的耐受能力有所增加,此现象作为一种心肌内源性自我保护方式已达共识。其表现形式有两种,一种是人们所熟知的缺血预适应现象,它可由不同方式在不同场合下被诱导发生并发挥其保护相应靶器官的作用;     

心肌缺血预适应对急性心肌梗塞的影响

目的 :评价心肌缺血预适应对急性心肌梗塞患者梗塞范围及近期预后的影响。方法 :76例初发 AMI并接受住院治疗的患者 ,按梗塞前 4 8h有无心绞痛分为缺血预适应 (A)组 (n=4 4 )、无缺血预适应 (B)组 (n=32 ) ,对比两组患者的临床资料。结果 :A组比 B组的心肌梗塞范围小 (P<0 .0 5 ) ,血清心肌酶学峰值低 (P<0 .0 5 ) ,恶性心律失常、心力衰竭、心源性休克发生率及病死率均明显降低 (P<0 .0 5 )。结论 :心肌缺血预适应具有保护心肌、缩小梗塞范围 ,改善初梗患者近期预后的作用。     

不同强度的无创性肢体缺血预适应与经典缺血预适应对大鼠心肌保护作用的对比

目的:对比不同强度的无创性肢体缺血预适应与经典缺血预适应对大鼠心肌的保护作用.方法:将健康成年雄性wistar大鼠40只,随机平分为4组:经典缺血预适应组(A组)、单下肢远程缺血预适应组(B组)、双下肢远程缺血预适应组(C组)、四肢远程缺血预适应组(D组).测定血清肌酸激酶(CK)、肌酸激酶同工酶(CK-MB).最后取心脏行心脏缺血范围(area at risk,AAR)、梗死范围(infarcted area,IA)测定.结果:(1)CK和CK-MB:B组及C组的CK和CK-MB活性与A组比均有明显下降(P＜0.05),且B组下降最明显.(2)心肌梗死面积(坏死区占左心室重量百分比):与A组比,B组、C组及D组均有明显下降(P＜0.05),且B和C组下降最明显,两者无明显差异.结论:无创性肢体缺血预适应比经典缺血预适应对大鼠心肌的保护作用更好.且结扎单下肢对大鼠心肌缺血再灌注的保护作用最强.     

缺血预适应在心血管疾病中的研究进展

短时间缺血可保护心脏免受更长更严重的缺血性损伤、改善心室功能及病理损伤，此现象称“缺血预适应”。可分为：经典的早期预适应及延迟性预适应，其代偿性机制各不相同，对其机制的综合理解，尤其是对预适应模拟物质的研究和发现将为临床治疗提供理想策略。     

MTS比色法检测嗜中性粒细胞产生的活性氧

目的 建立一种简便可靠的吞噬细胞“呼吸爆发”检测方法。方法 以MTS为受氢体检测嗜中性粒细胞受激发后产生的超氧离子，从而间接反映其“呼吸爆发”发生情况。结果 该法与常用的高铁细胞色素C还原法有良好的相关性，Y（MTS法）＝2．307X－0．291，r=0.9941。19例反复感染患者的嗜中性粒细胞的活性氧产量明显低于健康人。结论 该法是一种简便可靠的吞噬细胞“呼吸爆发”检测方法，可用于吞噬细胞功能的检测。     

缺血延迟预适应对心肌缺血再灌注所致细胞凋亡的保护

目的：分析心肌缺血延迟预适应能否抑制心肌缺血再灌注后心肌细胞凋亡的发生及其发生的可能原因。 方法：①实验于2003-08／2004-12在中山大学中西医研究所完成。选用出生两三个月的SD大鼠32只，雌雄不拘。②随机将大鼠分为4组：正常对照组（不做任何处理），假手术组（只穿线，不结扎），缺血再灌注组（采用经典大鼠冠状动脉结扎，缺血1h，再灌注1h），延迟缺血预处理组（采用经典大鼠冠状动脉结扎，缺血5min再灌注5min，重复3个缺血预处理，24h后，缺血1h，再灌注1h。③采用流式细胞仪测定心肌细胞凋亡率，反转录聚合酶链法检测Bcl-xl mRNA/Bcl-xs mRNA的表达情况，进行Bcl-xl的蛋白免疫印迹分析并利用免疫组织化学染色法检测大鼠心肌核因子KB亚单位P65蛋白的表达。 结果：大鼠32只均进入结果分析。①大鼠心肌细胞凋亡率：心肌缺血再灌注组明显升高（P〈0.01），延迟缺血预处理组明显低于缺血再灌注组（P〈0．01）。②大鼠心肌Bcl-xl mRNA与Bcl-xs mRNA表达的比值：缺血再灌注组明显低于正常对照组（P〈0．01），延迟缺血预处理组明显高于缺血再灌注组（P〈0．01）。③大鼠心肌Bcl-xl蛋白表达：缺血再灌注组明显减少（P〈0．01），延迟缺血预处理组明显高于缺血再灌注组（P〈0．01）。④大鼠心肌核因子κB P65蛋白表达：延迟缺血预处理组核因子κB P65发生核转位且明显高于与缺血再灌注组（P〈0．01）。 结论：心肌缺血延迟预适应可以减少心肌缺血再灌注造成的细胞凋亡，此种作用发生可能与核因子KB括化后促进Bcl-xl的表达，保护线粒体功能有关。     

缺血预适应与外科心肌保护

心肌保护在心脏外科发展中占有十分重要的地位。有资料表明 ,在缺血心肌细胞内发生的许多变化 ,如钙水平增加 ,膜损害 ,自由基产生 ,三磷酸腺苷 (ＡＴＰ)水平下降 ,氧耗竭等 ,造成代谢或缺氧应激 ,而同时细胞中的内源性保护机制将被激活。 1986年 ,Ｍｕｒｒｙ等〔1〕首次发现实验狗心肌在经历短暂性缺血后产生对随后连续、严重缺血的保护作用 ,限制心肌梗死的范围 ,增加心肌收缩力 ,减少再灌注心律失常发生 ,并称之为缺血预适应 (ｉｓｃｈｅｍｉｃｐｒｅｃｏｎｄｉｔｉｏｎ ｉｎｇ ,ＩＰ) ,为外科心肌保护提供了一个新的发展方向。1　缺血预…     

延迟心肌预缺血对急性心肌梗死预后保护的临床价值

目的　探讨延迟心肌预缺血对急性心肌梗死 (AMI)临床表现与近期预后的影响。方法　回顾性分析397例心绞痛 (心绞痛组 )病程大于 2周的AMI患者临床资料 ,与 371例无心绞痛史的AMI患者 (对照组 )比较。结果　心绞痛组合并休克、心衰者少于对照组 (分别为 1 0 .6 %对 1 6 .8%和 1 8.9%对 2 5 .9% ,P <0 .0 5 ) ,住院病死率也较低(1 0 .6 %对 1 6 .9% ,P <0 .0 5 ) ,肌酸激酶峰值较低 [(783± 4 83)U/L对 (1 0 86± 5 4 3)U/L ,P <0 .0 1 ],心绞痛组梗死前正规治疗者多于对照组 (6 8.8%对 2 8.6 % ,P <0 .0 0 1 ) ,但多部位梗死较少 (1 6 .4 %对 2 2 .3% ,P <0 .0 0 1 )。结论　与无心绞痛发作的患者比较 ,急性心肌梗死前有延迟心肌预缺血的冠心病患者梗死面积小 ,心源性休克及充血性心衰发生率低。     

远程缺血预适应对心肌保护作用的研究进展

远程缺血预适应(remote ischemia preconditioning,RIPC)是指某一器官在缺血预处理后,对远隔器官在随后发生的缺血事件中有保护作用.1993年PrzyKlenk 等通过对狗的心脏左旋支进行预处理时,发现其对之后左前降支的梗死也能减少其梗死面积.从而极大地拓展了对早期缺血预适应的认识,这被称为"心内远程预适应".之后又发现远程预适应并非局限于一个特定的脏器,它被称为"器官间预适应"或"远程预适应".     

Effect of ischemic preconditioning on reactive oxygen species-mediated ischemia--reperfusion injury in the isolated perfused rat lung

OBJECTIVE: To investigate the protective effect of ischemic preconditioning (IP) in the early phase of reperfusion injury. DESIGN AND METHODS: Control rat lungs were subjected to 3 h of perfusion, whereas the lungs of the ischemia-then-reperfusion (I/R) group were subjected to 2 h of cold ischemia following 30 min of perfusion. IP was performed by two cycles of 5-min ischemia followed by 5 min of reperfusion prior to 2-h cold ischemia. Lipid peroxidation and antioxidant status were determined in tissue samples. RESULTS: Lipid peroxidation and reduced/oxidized glutathione (GSH/GSSG) ratio were increased; antioxidant enzyme activities were decreased in the I/R group whereas lipid peroxidation and GSH/GSSG ratio were decreased; antioxidant enzyme activities were increased in the IP group. CONCLUSION: IP appeared to have a protective effect against reactive oxygen species-mediated I/R injury in isolated rat lung.     

缺血预处理对瓣膜置换术患者机体免疫功能的影响

目的:探讨在体外循环过程中运用缺血预处理对瓣膜置换术患者机体免疫功能的影响。方法:24例瓣膜置换手术患者,分为对照组(10例)和预处理组(14例),观察两组患者免疫球蛋白IgG、IgM和补体C3、C4及IL-2的变化。结果:两组患者IgG、IgM和C3、C4、IL-2水平均在术后1d较术前明显降低,IgG、IgM在术后3d有所恢复,术后5d恢复正常,C3术后3d恢复正常。预处理组C4和IL-2在术后3d即恢复至术前水平,较对照组明显提前。结论:缺血预处理能促进瓣膜置换术患者机体细胞免疫功能的恢复,而对机体体液免疫的影响则可能通过对补体系统调节而实现。     

The effects of tamoxifen and its metabolites on platelet function and release of reactive oxygen intermediates

Tamoxifen is effective in the prevention and treatment of breast cancer, but its use is associated with an increased risk of thrombosis. The mechanism for this effect is unknown. Reactive oxygen intermediates enhance platelet-dependent thrombosis, and in oncological studies, tamoxifen has been shown to increase production of reactive oxygen species. Therefore, the effects of tamoxifen and its bioactive metabolites on platelet activity and platelet reactive oxygen species were determined. Platelets were incubated with tamoxifen or the metabolites 4-hydroxy-tamoxifen (4-OH), N-desmethyl tamoxifen, or 4-hydroxy-N-desmethyl tamoxifen (endoxifen). Tamoxifen metabolites have been previously shown to possess enhanced bioactivity, and consistent with this observation, tamoxifen metabolites but not tamoxifen modestly increased platelet aggregation. These effects were similar with platelets isolated from male or female subjects. Platelet nitric oxide release or cGMP levels were not altered by incubation with tamoxifen or any of its metabolites. Incubation with tamoxifen metabolites increased stimulation-dependent platelet superoxide release [8.1 +/- 1.6 arbitrary units (a.u.) for control versus 15.2 +/- 3.5 a.u. for 4-OH; P < 0.01]. Coincubation with a superoxide dismutase mimetic eliminated the tamoxifen metabolite-induced enhancement of platelet aggregation. Corresponding to increased superoxide release, incubation with tamoxifen metabolites enhanced the functional activation of NADPH oxidase as determined by phosphorylation of its subunits p47(phox) and p67(phox). In summary, incubation of platelets with the active metabolites of tamoxifen increases stimulation-dependent superoxide release through a NADPH oxidase-dependent mechanism. This results in modest changes in platelet function and seems to be consistent with previous oncological studies demonstrating tamoxifen-dependent increase in reactive oxygen species generation.     

缺血预处理对缺血骨骼肌收缩功能的影响

背景缺血预处理能有效提高骨骼肌缺血耐受性,减轻骨骼肌缺血再灌注期间的坏死范围,但缺血预处理对骨骼肌收缩功能的影响文献报道不多.目的探讨缺血预处理对骨骼肌缺血再灌注期间收缩功能的影响.设计以实验动物为研究对象的随机对照研究.单位华中科技大学同济医学院及解放军第二五二医院.材料实验地点为解放军第二五二医院中心实验室.选用健康雄性SD大鼠14只.方法采用大鼠后肢缺血再灌注模型,将14只大鼠随机分为对照组和实验组.对照组持续缺血4 h,再灌注1 h;实验组缺血5 min,再灌注5 min,重复3次后,持续缺血4 h再灌注1 h.测定缺血再灌注期间腓肠肌收缩功能变化及再灌注1 h后,血清磷酸激酶(CK),丙二醛和腓肠肌99锝m亚甲基二磷酸钠(99TcmMDP)吸收量变化.主要观察指标缺血预处理对腓肠肌收缩力及对血清CK,丙二醛及99TcmMDP吸收量的影响.结果实验组腓肠肌收缩力在缺血4h时为(14.32±5.05)g,再灌注1 h时为(25.71±7.58)g,对照组分别为(0,4 73±2.05)g,两者相比差异有显著性意义(P＜0.05),实验组血清CK为(104.85±9.84)nkat/L,丙二醛为(3988.60±455.92)nmol/L,99TcmMDP吸收量为(56.0±8.1)mBq/g·mir,对照组CK为(136.36±14.50)nkat/L,丙二醛为(6 542.90±536.72)nmol/L,99TcmMDP吸收量为(97.3±5.8)mBq/g·min,两者相比差异有显著性意义(P＜0.05,P＜0.01).结论缺血预处理能有效改善缺血再灌注期间骨骼肌的收缩力,减轻骨骼肌坏死程度.因此,缺血预处理对缺血骨骼肌的收缩功能具有保护作用.     

冠脉血流显像技术评价缺血预适应对冠脉反应性充血的影响

目的:应用冠脉血流显像技术评价缺血预适应对冠脉反应性充血的影响。方法:将16条杂种犬分为二组:反复三次短暂性缺血预处理组(IP组,n=8)以及在预处理之前静脉注射NOS抑制剂L-NAME组(L-NAME组,n=8)。应用冠脉血流显像程序取前降支远端血流频谱。分别在基础状态、最后一次预适应后5分钟进行短暂性冠脉结扎(20s)和再松放(反应性充血),自短暂性结扎前起连续记录血流频谱,测量基础状态和最大充血状态下峰值速度、速度时间积分以及充血开始至最大充血时的时间(DPT)。计算充血时最大峰值血流速度与基础速度比值、速度时间积分比值(即PRV∶BV和VTIPR∶VTIBASE)。测算左室射血分数(EF)。结果:IP组缺血预适应后各反应性充血指标明显低于基础状态,而L-NAME组预适应后仅VTIPR∶VTIBASE低于基础状态,而DPT和PRV∶BV差异无显著性意义。结论:应用冠脉血流显像技术可以发现缺血预适应后反应性充血的改变,反应性充血量减少,但充血率增快,充血率与NO合成有关。     

Effect of adrenal function on gastrointestinal peptide release in experimental cardiac arrest

Pancreatic polypeptide (PP), neurotensin, substance P, and vasoactive intestinal polypeptide (VIP) are peptides that modify various autonomic and neural functions. These substances are secreted into the blood in response to physiologic stimuli affecting the gastrointestinal tract. To determine the effect of adrenal hormones on gastrointestinal peptide release we measured blood levels of PP, VIP, substance P, and neurotensin in adrenalectomized and intact dogs undergoing cardiac arrest and cardiopulmonary resuscitation (CPR), a condition associated with maximal adrenal stimulation. One hour after completion of abdominal surgery consisting of bilateral adrenalectomy or exposure of the adrenal glands (sham operation), ventricular fibrillation was induced in 19 dogs by direct ventricular discharge. Despite marked elevations of plasma epinephrine and norepinephrine, CPR was associated with minimal endocrine gastrointestinal involvement, restricted to increased VIP levels in sham-operated dogs. No specific gastrointestinal peptide response to cardiac arrest was seen in adrenalectomized animals, but their plasma PP and VIP levels were higher than those of sham-operated dogs. Therefore, acute maximal adrenal stimulation is associated with selective VIP release. In addition, the higher level of the vagally controlled plasma PP in adrenalectomized animals suggests a tonic inhibitory effect of adrenal secretions on the release of this peptide.     

促红细胞生成素预处理对肢体缺血再灌注损伤的影响

目的：观察促红细胞生成素预处理对骨骼肌缺血再灌注损伤的影响。 方法：实验于2004—08／2005—01在解放军第二五二医院中心实验室完成。①采用大鼠右后肢缺血再灌注模型，将30只实验大鼠随机分为3组，每组10只。假手术组：仅显露股血管鞘，不做缺血再灌注，经腹腔注射同体积生理盐水；对照组：经腹腔注射同体积生理盐水，持续缺血4h．再灌注1h。促红细胞生成素预处理组（预处理组）：经腹腔注射5000u／kg人重组促红细胞生成素，24h后持续缺血4h，再灌注1h。②测定各组血清磷酸激酶，乳酸脱氢酶丙二醛和腓肠肌^99Tc^m亚甲基二磷酸钠吸收量变化。③电镜观察腓肠肌超微结构变化。 结果：30只大鼠全部进入结果分析。①对照组和预处理组血清磷酸激酶[（121．627&;#177;18．112），（84．417&;#177;14．594）μkat／L]、乳酸脱氢酶[（20．065&;#177;4．676），（13．354&;#177;5．229）μkat/L]明显高于假手术组[（50．247&;#177;16．066），（7．732&;#177;1．256）μkat／L1（P〈0．05）；对照组和预处理组丙二醛[（10．36&;#177;2．65），（6．55．&;#177;2．19）nmol／L]及^99Tc^m亚甲基二磷酸钠吸收量[（16．69&;#177;3．14），（11．66&;#177;3．87）％／（g&;#183;min）]均明显高于假手术组[（3．54&;#177;1．89）nmol／L，（9．12&;#177;1．96）％／（g&;#183;min）（P〈0．05）]。②预处理组各指标与对照组相比显著降低（P〈0．05）。 结论：促红细胞生成素对肢体骨骼肌缺血再灌注损伤具有保护作用。     

Effect of neutrophil depletion on ischemic renal injury in the rat

Oxygen free radicals have been implicated in postischemic renal injury. However, the source of these oxygen free radicals has not been well defined. One potential source is activated neutrophils. Neutrophil depletion was produced in rats by using two different techniques, and the effect on ischemic injury was examined. Rabbit anti-rat neutrophil serum was prepared by immunizing a rabbit with a Percoll gradient centrifugation-purified (approximately 90%) suspension of rat neutrophils. Rats received antineutrophil serum in one of four protocols and were subsequently subjected to 40 minutes of renal artery occlusion. Control animals received nonimmune rabbit serum. The serum creatinine levels 24 hours after ischemia were not different between control and immune serum-treated rats in any of the protocols despite significant reductions in absolute neutrophil count. In a separate study, nitrogen mustard was administered 40 hours before ischemia. Nitrogen mustard-treated rats developed moderate neutropenia and 24 hours after ischemia had lower serum creatinine levels and higher inulin clearance. However, nitrogen mustard-treated rats lost 31.5 +/- 5 gm body weight in the 2 days after nitrogen mustard administration, whereas control animals gained 5.9 +/- 5.9 gm during the same interval. Furthermore, among nitrogen mustard-treated rats there was no correlation between neutrophil count and postischemic renal function. It is thus possible that the beneficial effects of nitrogen mustard were caused by a mechanism other than neutrophil depletion. In summary, in four protocols that used antineutrophil serum, neutropenia did not protect against ischemic injury. Nitrogen mustard provided protection, but probably by a neutrophil-independent mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)     

促红细胞生成素预处理对肢体缺血再灌注损伤的影响

目的:观察促红细胞生成素预处理对骨骼肌缺血再灌注损伤的影响。方法:实验于2004-08/2005-01在解放军第二五二医院中心实验室完成。①采用大鼠右后肢缺血再灌注模型,将30只实验大鼠随机分为3组,每组10只。假手术组:仅显露股血管鞘,不做缺血再灌注,经腹腔注射同体积生理盐水;对照组:经腹腔注射同体积生理盐水,持续缺血4h,再灌注1h。促红细胞生成素预处理组(预处理组):经腹腔注射5000u/kg人重组促红细胞生成素,24h后持续缺血4h,再灌注1h。②测定各组血清磷酸激酶,乳酸脱氢酶丙二醛和腓肠肌99Tcm亚甲基二磷酸钠吸收量变化。③电镜观察腓肠肌超微结构变化。结果:30只大鼠全部进入结果分析。①对照组和预处理组血清磷酸激酶[(121.627±18.112),(84.417±14.594)μkat/L]、乳酸脱氢酶[(20.065±4.676),(13.354±5.229)μkat/L]明显高于假手术组[(50.247±16.066),(7.732±1.256)μkat/L](P<0.05);对照组和预处理组丙二醛[(10.36±2.65),(6.55.±2.19)nmol/L]及99Tcm亚甲基二磷酸钠吸收量[(16.69±3.14),(11.66±3.87)%/(g·min)]均明显高于假手术组[(3.54±1.89)nmol/L,(9.12±1.96)%/(g·min)(P<0.05)]。②预处理组各指标与对照组相比显著降低(P<0.05)。结论:促红细胞生成素对肢体骨骼肌缺血再灌注损伤具有保护作用。