缝隙连接蛋白43在老年大鼠缺血性室性心律失常中的作用

目的 探讨缝隙连接蛋白43(Cx43)在老年大鼠心室肌中的表达及急性心肌缺血时迷走神经刺激对老年大鼠缺血性室性心律失常的影响.方法 结扎大鼠冠状动脉前降支制备急性心肌缺血模型,随机分为(1)成年组:假手术组(SO,n=10)、心肌缺血组(MI,n=15)、心肌缺血+迷走神经刺激组(MI-VNS,n=15)、心肌缺血+迷走神经刺激+阿托品(0.5 mg/kg)组(MI-VNS-Atr,n=13)和心肌缺血+迷走神经刺激+生胃酮(10 mg/kg)组(MI-VNS-CBX,n=11).(2)老年组:假手术组(SO,n=10)、心肌缺血组(MI,n=15)、心肌缺血+迷走神经刺激组(MI-VNS,n=15)、心肌缺血+迷走神经刺激+阿托品(0.5 mg/kg)组(M1-VNS-Atr,n=13)和心肌缺血+迷走神经刺激+生胃酮(10 mg/kg)组(MI-VNS-CBX,n=11).心电图监测室性心律失常的发生.Western blot分析Cx43蛋白表达变化.结果 结扎冠状动脉30 min内,老年MI组室性心动过速(室速)和心室颤动(室颤)发生率较成年MI组显著增加(P＜0.05);老年MI-VS组室速和室颤发生率与老年MI组相比差异无统计学意义(P＞0.05),但老年MI-VS组不可逆性室颤发生率较老年MI组明显减少(P＜0.05).冠状动脉结扎30 min后,缺血没有引起成年组和老年组的总Cx43含量改变(P＜0.05);但缺血引起成年组和老年组的非磷酸化Cx43含量明显增加,迷走神经刺激能够明显抑制成年组和老年组中缺血引起的Cx43脱磷酸化(P＜0.05);而阿托品和生胃酮明显阻断了迷走神经刺激抑制缺血引起的Cx43脱磷酸化的作用(P＜0.05).但实验发现老年SO组Cx43表达较成年SO组明显减少(P＜0.05).结论 老年大鼠缺血性室性心律失常发生率明显增加,而迷走神经刺激的抗缺血性室性心律失常的效应明显减弱,其机制可能与老年大鼠心室肌Cx43表达较成年大鼠明显减少有关.     

交感神经刺激对大鼠缺血性室性心律失常的影响及其机制的探讨

目的 探讨大鼠急性心肌缺血时交感神经刺激对室性心律失常的影响及其潜在的机制.方法 结扎大鼠冠状动脉前降支制备急性心肌缺血模型后随机分组作为心肌缺血组(MI组,n=25)、缺血+交感神经刺激组(MI-SS组,n=25)、交感神经刺激+酚妥拉明+缺血组(MI-SS-Phen组,n=15)、交感神经刺激+普萘洛尔+缺血组(MI-SS-Prop组,n=15)和假手术组(SO组,n=20).心电图监测室性心律失常的发生.蛋白免疫印记法(Western blot)检测缝隙连接蛋白43(Cx43)的磷酸化蛋白及总量表达变化.逆转录聚合酶链反应(PCR)分析Cx43 mRNA的表达变化.免疫荧光观察Cx43表达分布情况.结果 结扎冠状动脉30 min内MI、MI-SS和MI-SS-Phen组分别有1、3和2只大鼠死于心室颤动(室颤);MI-SS组室性心动过速(室速)/室颤发生率(80.0%,20/25)较MI组(52.0%,13/25)明显增加(P＜0.05);与MI-SS组相比,普萘洛尔明显阻断了交感神经刺激促室速/室颤发生的作用(13.3%,2/15,P＜0.05).冠状动脉结扎30 min后,MI组磷酸化Cx43的比例较SO组显著降低(P＜0.05),但其总量并未减少(P＞0.05).与MI组相比,MI-SS组磷酸化Cx43的比例明显增加(P＜0.05),同时其蛋白总量的表达显著降低(P＜0.05);普萘洛尔显著抑制了交感神经刺激导致的Cx43蛋白降解的作用,同时抑制了缺血引起的Cx43脱磷酸化(P＜0.05).MI和MI-SS组Cx43mRNA表达均较SO组显著减少(P＜0.05).免疫荧光结果 显示,与SO组相比,MI组Cx43由端-端连接转化为侧-侧连接,而MI-SS组Cx43分布明显紊乱,不能分辨出Cx43的分布模式.结论 交感神经刺激能够促进室性心律失常的发生,可能主要与β肾上腺素受体的激活从而促进了Cx43的降解有关.     

白藜芦醇降低大鼠心肌梗死后室性心律失常的研究

目的:探讨白藜芦醇对大鼠心肌梗死(myocardial infarction,MI)后室性心律失常的影响及可能机制。方法:将成功建立心肌梗死模型的24只SD大鼠随机分为MI组(n=12)和白藜芦醇组(n=12),另设假手术组(n=12),其中白藜芦醇组给予白藜芦醇10 mg/(kg·d)灌胃,MI组和假手术组给予5%羧甲基纤维素钠灌胃。4周后,所有大鼠行电生理检查;ELISA法检测血清白细胞介素(IL)-1β、肿瘤坏死因子(TNF)-α水平;免疫组化和Western blot检测心肌缝隙连接蛋白43(Cx43)表达水平。结果:与假手术组相比,MI组室性心律失常的诱发率明显增加,心室颤动阈值显著降低,血清IL-1β、TNF-α水平明显增加,Cx43表达水平显著降低(P0.05);与MI组相比,白藜芦醇组心律失常诱发率显著降低,心室颤动阈值增加,血清IL-1β、TNF-α水平明显降低,Cx43表达明显增加(P0.05),但白藜芦醇不能使上述指标恢复到假手术组水平(P0.05)。结论:白藜芦醇可有效降低大鼠心肌梗死后室性心律失常的发生,其机制可能与提高心肌Cx43表达,降低炎症反应有关。     

大鼠心肌梗死后左心室重构、电重构和交感神经重构的关系

目的 应用超声心动图、免疫组织化学技术和电生理技术记录心肌梗死大鼠梗死周边区的有效不应期(ERP)及缝隙连接蛋白43(Cx43)改变,交感神经神经(TH)及神经生长因子(GAP43)改变,探讨心肌梗死大鼠心室重构、电重构及交感神经重构之间的关系.方法 将成年SD大鼠30只,随机分为假手术组和心肌梗死组.假手术组仅开胸,不结扎冠状动脉.结果 与假手术组相比,心肌梗死组LVIDd、LVIDs均显著增大(P＜0.01),EF和FS缩短率显著降低(P＜0.01).与假手术组相比,心肌梗死组梗死周边区ERP显著缩短,差异有统计学意义(P＜0.01).心肌梗死组Cx43阳性蛋白表达低于假手术组,差异有统计学意义(P＜0.01).与假手术组相比,心肌梗死组GAP43阳性神经密度明显增加,差异有统计学意义(P＜0.01).心肌梗死组TH阳性神经密度不均一明显增加,差异有统计学意义(P＜0.01).结论 大鼠心肌梗死后心室不但发生结构重构,同时也会发生神经重构和电重构,以及三者之间相互影响和共同作用导致恶性心律失常和猝死的发生.     

TNF-α诱导连接蛋白重构在心肌梗死后室性心律失常发生中的作用

目的:研究肿瘤坏死因子-α(TNF-α)对大鼠心肌梗死后连接蛋白(Cx)43重构调节作用及其对室性心律失常发生的影响。方法:采用液氮冷冻法建立大鼠心肌梗死模型。将60只雄性大鼠随机分为3组:心肌梗死组(MI组,20只)、TNF-α螯合剂组(rhTNFR:Fc组,20只)和假手术组(Sham组,20只)。在心肌梗死模型建立30d后,运用程序电刺激方法,观察室性心律失常的诱发情况,应用Western Blot检测TNF-α、Cx43磷酸化和非磷酸化的表达水平。采用激光共聚焦显微镜方法,观察TNF-α的表达、Cx43的分布情况。结果:与假手术组比较,MI组大鼠心肌组织TNF-α表达明显增加(P0.05);Cx43磷酸化水平显著降低(P0.05),而Cx43非磷酸化水平增加(P0.05),Cx43分布呈现不均一分布;该组室性心律失常的诱发率明显增高(P0.05)。与MI组比较,rhTNFR:Fc组大鼠心肌组织TNF-α表达显著减少(P0.05);Cx43磷酸化水平表达增加(P0.05),Cx43非磷酸化水平下降(P0.05),而Cx43不均一分布有所减轻;室性心律失常的诱发率亦明显下降(P0.05)。结论:心肌梗死发生后,TNF-α可以诱导Cx43表达和分布重构,其在心肌梗死后室性心律失常发生中可能发挥重要作用。     

同种异体骨髓间充质干细胞转染连接蛋白43基因后移植对心肌梗死大鼠心功能的影响

目的:研究转染真核表达质粒pbudCEA.1_Cx43后的骨髓间充质干细胞(bone mesenchymal stem cells,BMSCs)移植对心肌梗死大鼠左心功能的影响,明确同种异体干细胞及连接蛋白43(Connexin43,Cx43)基因转染于细胞移植治疗急性心肌梗死的可行性及效果.方法:清洁级SD大鼠60只,随机选出11只作为假手术组,其余大鼠制成心肌梗死模型,再随机分为四组:对照组(n=11);细胞移植组(n=12);基因移植组(n=13);空载体移植组(n=13).另取清洁雄性SD大鼠5只,作为BMSCs供体.心肌梗死各组大鼠结扎前降支后1～3小时心肌内移植入相应的细胞或培养基,移植后6周检测心功能并取心脏检测各种相关指标.结果:同种异体大鼠BMSCs可在梗死心肌组织定居、生存;与对照组比较,假手术组、细胞移植组、基因移植组和空载体移植组左心功能均明显改善(P＜0.05),基因移植组优于细胞移植组和空载体移植组(P＜0.05).结论:BMSCs转染Cx43基因后移植治疗急性心肌梗死可行、有效.     

多西环素对心肌梗死模型大鼠缝隙连接蛋白43表达的影响

目的探讨心肌梗死模型大鼠心肌组织缝隙连接蛋白43(Cx43)表达的变化及多西环素对心肌梗死大鼠Cx43的影响。方法选择符合实验要求的大鼠,将其分为假手术组和模型组,假手术组只穿线,不结扎,将模型组分为多西环素组、心肌梗死组并分别给予多西环素与生理盐水。手术1个月后检测模型大鼠其心肌细胞Cx43表达相关变化情况。结果心肌梗死组Cx43 mRNA与假手术组比较差异有统计学意义(P0.05);多西环素组Cx43 mRNA表达量,但与心肌梗死组比较差异无统计学意义(P0.05)。多西环素组Cx43表达量高于心肌梗死组,差异有统计学意义(P0.05),但低于假手术组(P0.05)。多西环素组心肌Cx43相对表达量高于心肌梗死组,差异有统计学意义(P0.05);但低于假手术组(P0.05)。结论多西环素对改善心肌梗死大鼠相关的缝隙连接蛋白重构有一定的促进作用。     

消融左侧星状神经节对犬急性心肌缺血后缝隙连接蛋白43表达的影响

目的 探讨消融左侧星状神经节(LSG)对犬急性心肌缺血后缝隙连接蛋白43表达的影响.方法 18只成年杂种犬随机分为三组:假手术组(SO,n=6)、心肌梗死组(MI,n=6)、消融组(n=6).SO组游离LSG而不予以射频能量,暴露左前降支但不予以结扎;MI组游离LSG但不行消融术,暴露左前降支,穿线结扎;消融组在消融LSG后30min再结扎左前降支.记录SO组和消融组消融前后30min内心率变异性[(HRV,包括低频(LF)、高频(HF)、LF/HF值]的变化,记录各组MI后1h内室性心律失常发生情况.蛋白免疫印记法(Westernblot)检测各组内缝隙连接蛋白43(Cx43)的总量及磷酸化的表达变化.逆转录聚合酶链反应(PCR)分析各组内Cx43 m RNA的表达变化.结果 SO组消融前后HF、LF及LF/HF无明显差异.与消融前相比,消融组消融后LF值和LF/HF值显著降低,HF值明显升高.SO组无室性心律失常发生.与MI组相比,消融组室性早搏、成对室性早搏及非持续性室性心动过速的发作次数、持续时间明显降低(P均0.05).与SO组相比,MI组Cx43蛋白、磷酸化Cx43蛋白及Cx43 m RNA含量显著降低(P均0.05).与MI组相比,消融组Cx43蛋白、磷酸化Cx43蛋白及Cx43m RNA含量显著升高,但与SO组相比无明显差异.结论 消融LSG可降低心脏交感神经活性,上调心肌梗死后心肌Cx43的表达有抗心律失常作用.     

美托洛尔对急性心肌梗死大鼠心肌神经生长因子表达和神经重构的影响

目的 探讨β受体阻滞剂美托洛尔对大鼠急性心肌梗死(AMI)后心肌神经生长因子(NGF)表达和交感神经再生的影响.方法 结扎大鼠左前降支,建立AMI模型,存活者随机分为美托洛尔治疗组(MI-B组,n=10)和梗死对照组(MI-C组,n=10),另设假手术组(S组,n=8).MI-B组给予4周美托洛尔治疗,MI-C组和S组给予同体积生理盐水静脉注射和灌胃,4周后检测梗死周边区和梗死远端心脏神经纤维分布和密度以及心肌NGF基因和蛋白表达的变化.结果 与S组相比,MI-C组梗死周边和梗死远端心肌组织中NGF基因和蛋白表达明显升高(P＜0.05),梗死周边和梗死远端神经支配密度增高(P＜0.01).与MI-C组比较,MI-B组心肌细胞内NGF表达明显下降(P＜0.05),神经支配密度亦明显下降(P＜0.01).结论 早期美托洛尔治疗AMI可以改善心肌NGF表达和交感神经再生.美托洛尔改善交感神经再生的作用机制至少部分与其降低神经生长因子的表达和释放作用有关.     

益气活血药对心肌梗死大鼠心室缝隙连接蛋白43表达及室颤发生的影响

目的探讨益气活血药(生脉注射液联合血塞通注射液)对心肌梗死大鼠心室缝隙连接蛋白43(Cx43)表达及室颤发生的影响。方法采用结扎心脏左冠状动脉前降支的方法建立心肌梗死大鼠模型,另设假手术(只穿线,不结扎)作对照。术后随机分为模型组、假手术组、卡托普利组和益气活血组。卡托普利组给予卡托普利片4.39 mg/(kg·d)溶解灌胃;益气活血组给予生脉注射液3.51mL/(kg·d),血塞通注射液17.54mg/(kg·d)腹腔注射;模型组和假手术组给予生理盐水,疗程4周。治疗结束后取材,采用real time PCR法检测左心室梗死边缘区Cx43mRNA的表达;Western blot法检测Cx43蛋白表达;在体电刺激记录室颤诱发率。结果与假手术组比较,模型组Cx43的mRNA和蛋白表达均显著降低(P0.05或P0.01);与模型组比较,卡托普利组和益气活血组Cx43的mRNA和蛋白表达均显著升高(P0.05或P0.01)。在体电刺激室颤诱发率模型组最高,卡托普利组和益气活血组的室颤诱发率降低,差异有统计学意义(P0.05)。结论生脉注射液联合血塞通注射液可以减少心肌梗死后室颤的发生,其机制与改善心室Cx43表达有关。     

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.