腺苷预适应对心脏的保护效应及机制探讨

目的探讨腺苷预适应对心肌缺血/再灌注(I/R)损伤的保护作用.方法通过建立家兔心脏I/R模型,观察腺苷预适应对I/R心肌损伤的保护效应,以左心室功能恢复率、心肌梗死面积、心肌细胞肌酸激酶(CK)和乳酸脱氢酶(LDH)漏出率的变化作为观察指标.结果腺苷预适应组心功能恢复明显好于对照组(P均＜0.01),CK、LDH漏出率及心肌梗死面积均低于单纯I/R组(P均＜0.01),这些心脏保护效应均被腺苷A1受体拮抗剂DPCPX阻断.结论腺苷通过其A1受体的激活介导了缺血预适应对I/R损伤的保护效应.     

不同缺血预处理对未成熟心肌细胞功能的影响

目的比较不同方法的缺血预处理对未成熟心肌细胞功能的影响。方法采用Langendorff离体心脏灌注模型。分为4组:缺血/再灌注(I/R)组,离体心脏灌注15min转为工作心15min后停灌45min,恢复灌注15min改为工作心30min;心脏缺血预处理(MIP)组:离体心脏灌注15min转为工作心15min后反复2次缺血5min/再灌注5min,然后重复I/R组缺血/再灌注方法;肾缺血预处理(RIP)组:反复三次阻断左肾动脉5min,放开5min,切取心脏,重复I/R组方法;双下肢缺血预处理(DLIP)组:反复3次捆扎双下肢5min,松开5min,切取心脏,重复I/R组方法。以血清肌酸激酶(CK)和乳酸脱氢酶(LDH)漏出率、心肌组织三磷腺苷(ATP)和丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、心肌细胞内Ca2+含量、心肌线粒体Ca2+-ATPase活性及其Ca2+含量、心肌线粒体合成三磷腺苷能力[ATP]m作为观察指标。结果MIP、RIP及DLIP组ATP含量、SOD活性、心肌线粒体Ca2+-ATPase活性、[ATP]m均高于I/R组(P<0.01),MDA含量、CK、LDH漏出率、心肌细胞内Ca2+含量、心肌线粒体Ca2+含量均低于I/R组(P<0.01)。结论肾缺血预处理、双下肢缺血预处理与心脏缺血预处理有同等的心肌细胞保护作用。     

血管紧张素Ⅱ预处理对体外大鼠缺血再灌注心肌的保护作用

目的 :研究血管紧张素Ⅱ (AngⅡ )预处理是否对缺血 /再灌注 (I/R)心肌有保护作用 ,其作用是否通过蛋白激酶C(proteinkinaseC ,PKC)及线粒体ATP依赖性钾通道 (KATP)而起作用。方法 :4 0只SD大鼠 ,随机分为 5组 (每组各 8只 ) :AngⅡ预处理组 (APC组 )、缬沙坦加AngⅡ预处理组 (VAPC组 )、PKC阻滞剂chelerythine加AngⅡ预处理组 (CLT组 )、线粒体KATP通道阻滞剂 5 Hydroxydecanoate加AngⅡ预处理组 (5 HD组 )和对照组(C组 )。应用Langendorff主动脉逆行灌流的体外大鼠I/R心脏模型 ,观察各组大鼠I/R后心肌细胞乳酸脱氢酶(LDH)及肌酸激酶 (CK)漏出率、心肌组织三磷酸腺苷 (ATP)含量及心功能指标 (LVSP与±dp/dtmax)。结果 :APC组CK、LDH漏出率较C组明显减少 (P <0 .0 1) ,心肌ATP含量较C组增加 (P <0 .0 1) ,心功能 (LVSP与±dp/dtmax)较C组改善。VAPC组、CLT组及 5 HD组上述各指标 (LDH、CK、ATP、LVSP及±dp/dtmax)分别与C组相应的各指标比较差异无统计学意义 (P >0 .0 5 )。结论 :AngⅡ预处理对I/R心肌有保护作用     

清开灵注射液对大鼠心肌缺血再灌注损伤的保护作用

目的探讨清开灵(QKL)注射液对大鼠实验性缺血/再灌注(I/R)损伤的保护作用及机制。方法 Wistar大鼠40只,随机分为假手术组、模型组、清开灵注射液高剂量组(QKL 40 mg/kg)、清开灵注射液低剂量组(QKL 20 mg/kg),每组10只。结扎大鼠冠状动脉左前降支40 min、再灌120 min制备心肌I/R损伤模型。检测QKL对I/R损伤大鼠血清中LDH、CK、AST、SOD、MDA、NO含量的影响;同时以TTC染色检测心肌梗死面积变化。结果与模型组比较,QKL高剂量组及QKL低剂量组大鼠血清中LDH、CK、AST含量明显降低(P<0.05),SOD活性明显升高(P<0.01),MDA及NO含量降低(P<0.01)。QKL高剂量组及QKL低剂量组心肌梗死面积明显低于模型组(P<0.05)。免疫组化法检测结果显示,QKL高剂量组及QKL低剂量组心肌细胞iNOS表达量低于模型组(P<0.05)。结论 QKL可能通过抑制iNOS,对大鼠心肌I/R损伤具有保护作用。     

罗格列酮在缺血预适应中对心肌保护作用的研究

目的:给予罗格列酮(ROS)预处理并且诱导大鼠心肌缺血预适应后,观察心肌梗死面积以及脂联素的分泌,探讨缺血预适应中脂联素的保护机制。方法:用随机数字发生器将SD雄性大鼠随机分为4组:①缺血再灌注组(I/R组);②缺血预适应组(IPC组);③罗格列酮+缺血再灌注组(ROS+I/R组);④罗格列酮+缺血预适应组(ROS+IPC组),各8只。通过RT-PCR测定大鼠心脏脂联素含量。测定大鼠心脏心肌梗死面积,观察脂联素含量。结果:ROS+IPC组脂联素的表达水平分别与ROS+I/R组、IPC组及I/R组相比,差别有显著统计学意义(P0.01)。结论:罗格列酮增加了脂联素的分泌,使其mRNA表达水平增高,减少了心肌梗死面积。这可能是罗格列酮在IPC中产生对心肌保护的主要机制之一。     

脂质胞壁酸诱导的预适应对自发性高血压大鼠心肌缺血再灌注损伤的保护作用

目的:探讨脂质胞壁酸(LTA)诱导的延迟预适应对自发性高血压大鼠(SHR)心脏缺血/再灌注(I/R)损伤的保护作用及诱导型一氧化氮合酶(iNOS)是否参与其作用。方法:采用结扎左冠状动脉前降支30min,再灌注复制大鼠心肌I/R模型,结扎前24h注射LTA,检测心肌再灌注60min后血清心肌型肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH),并用dUTP缺口末端标记法检测心肌细胞凋亡,用Western Blot方法检测凋亡蛋白Bcl-2和Bax的蛋白表达。同时采用实时RT-PCR技术和Western Blot方法分别检测心肌再灌注末iNOS mRNA和蛋白的表达。结果:与I/R组比较,LTA预适应组能显著减少室性心律失常(VA)评分值(P<0.01);LTA预适应还能明显减少I/R后血清CK-MB和LDH的漏出(P<0.01,P<0.05),减少心肌细胞凋亡(P<0.01),凋亡相关蛋白Bcl-2表达明显上调(P<0.01),而Bax蛋白表达则下调(P<0.01)。再灌注末,预适应组iNOS mRNA的平均相对表达量较I/R组增加了0.71倍(P<0.01),LTA预适应组iNOS蛋白的表达量较I/R组增加了0.96倍(P<0.05)。不论在LTA预适应前或缺血前期给予iNOS抑制剂氨基胍或是单独给予氨基胍,上述观测指标均与I/R组比较差异无统计学意义。结论:LTA预适应能显著减轻SHRI/R导致肥厚心肌的坏死和细胞凋亡,iNOS/NO作为触发和效应环节在介导LTA预适应中发挥关键作用。     

细胞膜钠钙交换蛋白在大鼠心肌缺血预适应及腺苷诱导预适应中的作用及其信号转导

目的 探讨细胞膜钠钙交换蛋白（NCX）在心肌缺血预适应及药物诱导预适应中的作用及可能的信号转导途径.方法 培养乳鼠心肌细胞随机分为缺血/再灌注组、缺血预适应组、腺苷预处理组、钙调素依赖蛋白激酶Ⅱ（CaMKⅡ）抑制剂KN-93＋缺血预适应组、KN-93＋腺苷预处理组及对照组.各组乳酸脱氢酶（LDH）漏出量用生化法测定（n=5）,钠钙交换蛋白mRNA表达以半定量RT-PCR检测（n=5）,NCX活性以液闪仪测定Na^＋依赖的^45Ca^2＋摄取率表示（n=5）.结果 （1）缺血/再灌注组LDH漏出量显著增加（P＜0.05）,缺血预适应及腺苷预处理组LDH漏出量均显著降低 （P＜0.05）;KN-93预作用后,缺血预适应及腺苷预处理组LDH漏出量均显著增加（P＜0.05）. （2）缺血/再灌注组NCX ^45Ca^2＋摄取率比对照组高（P＜0.005）.缺血预适应及腺苷预处理组较缺血/再灌注时NCX ^45Ca^2＋摄取率显著低（P＜0.05）,且腺苷预处理组NCX ^45Ca^2＋摄取率较缺血预适应组更低（P＜0.05）. KN-93＋缺血预适应组与缺血/再灌注组NCX ^45Ca^2＋摄取率差异无统计学意义, KN-93＋腺苷预处理组较缺血/再灌注组NCX ^45Ca^2＋摄取率低（P＜0.05）.（3） 缺血/再灌注组NCX mRNA的表达比对照组显著高（P＜0.05）;缺血预适应及腺苷预处理组NCX mRNA的表达均显著低（P＜0.05）;KN-93处理后缺血预适应组及腺苷预处理组NCX mRNA的表达水平显著高（P＜0.05）,且腺苷预处理组NCX mRNA的表达较缺血预适应组更高（P＜0.05）.结论 缺血预适应及腺苷预处理对心肌的保护作用与细胞膜NCX有关,缺血预适应中NCX对心肌损伤保护作用经CaMKⅡ介导,而在腺苷预处理中NCX对心肌损伤保护作用仅部分经CaMKⅡ介导.     

骨骼肌缺血预适应对心脏的保护作用

目的:确定骨骼肌缺血预适应对心肌坏死面积、超微结构及冠状动脉内皮相关因子的影响。方法:12只小型猪被随机分成缺血对照(C)组和远端预适应(RP)组,采用非开胸法建立心脏缺血再灌注(I/R)模型,通过球囊闭塞左股动脉造成骨骼肌短暂缺血。以三硝基四氮唑红确定心肌梗死范围;以电镜观察缺血心肌超微结构;同时动态观察I/R过程中左前降支(LAD)冠状动脉血中NO、血管性假血友病因子(vWF:Ag)、内皮素-1(ET-1)及丙二醛含量变化。结果:与C组相比,RP组明显减少心肌梗死范围,减轻心肌超微结构损伤,并明显增加LAD冠状动脉内的NO含量、降低vWF:Ag和ET-1的含量。结论:骨骼肌RP减少I/R所致心肌梗死范围,保护心肌超微结构,并对损伤冠状动脉内皮有一定保护作用。     

PI3K/Akt信号参与介导虎杖甙对缺血/再灌注心肌的保护作用

目的 探讨虎杖甙对小鼠心肌缺血/再灌注损伤的影响及可能机制。 方法 建立小鼠缺血/再灌注损伤模型,随机将小鼠分为5组（每组18只）:假手术组（Sham）、缺血/再灌注组（I/R）、缺血/再灌注+虎杖甙组（I/R+PD）、缺血/再灌注+虎杖甙+LY294002组（I/R+PD+LY294002）和缺血/再灌注+LY294002组（I/R+LY294002）。小鼠心脏超声检测心功能;Masson染色评估胶原容积分数（CVF);TTC染色测定小鼠心肌梗死面积;ELISA法检测血浆CK和LDH水平;Tunel法测定小鼠心肌细胞凋亡,Western blot检测p-Akt的表达。 结果 与Sham组相比,I/R组LVEF和LVFS值均显著降低（P<0.05）,心肌梗死面积、血浆CK和LDH水平均显著增加（P<0.05）,心肌细胞凋亡显著增加（P<0.05）,心肌CVF值显著增加（P<0.05）,心肌p-Akt蛋白表达显著增加（P<0.05）;与I/R组相比,I/R+PD组LVEF和LVFS值均显著增加（P<0.05）,心肌梗死面积、血浆CK和LDH水平均显著降低（P<0.05）,心肌细胞凋亡显著减少（P<0.05）,心肌CVF值显著降低（P<0.05）,心肌p-Akt蛋白表达进一步增加（P<0.05）;与I/R+PD组相比,I/R+PD+LY294002组LVEF和LVFS值均显著降低（P<0.05）,心肌梗死面积、血浆CK和LDH水平均显著增加（P<0.05）,心肌细胞凋亡显著增加（P<0.05）,心肌CVF值显著增加（P<0.05）,心肌p-Akt蛋白表达显著减少（P<0.05）。 结论 虎杖甙通过激活PI3K/Akt信号通路减轻心肌I/R损伤。     

冠状动脉内给予乙酰半胱氨酸对缺血再灌注心肌梗死面积的影响

目的:观察冠状动脉内给予小剂量N-乙酰半胱氨酸(NAC)对家兔心肌缺血再灌注(I/R)后心肌梗死面积的影响。方法:36只家兔随机分为假手术组(S组,12只)、(I/R组,12只)和NAC治疗组(NAC组,12只)。NAC组在结扎前降支1h后恢复血流灌注,然后用无损伤血管钳夹闭主动脉和肺动脉10s,同时于心尖部注入200g/L的NAC溶液0.5ml,S组和I/R组给予0.5ml0.9%氯化钠溶液。再灌注3h后从颈动脉采血,测定血清肌酸磷酸激酶(CK)、乳酸脱氢酶(LDH)的含量和谷胱甘肽过氧化物酶(GPH-Px)活性。蛋白印迹法检测缺血区心肌组织中I-κB的表达,并分别用双重染色测定心肌梗死面积。结果:与I/R组比较,NAC组CK和LDH明显降低(P<0.01),而GPH-Px活性则明显增高(P<0.01),缺血区心肌组织中I-κB的表达明显减少,心肌梗死面积也显著减少(P<0.01)。结论:冠状动脉内给予小剂量NAC能明显减少心肌I/R后的心肌梗死面积。     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.