线粒体电压依赖阴离子通道对携带线粒体DNAA4263G突变的细胞株线粒体钙循环的影响

目的 研究线粒体外膜电压依赖阴离子通道(voltage-dependent anion channel,VDAC)在携带线粒体DNA (mitochondrial DNA, mtDNA) A4263G突变的细胞株线粒体钙循环中的作用. 方法 对该家系的4个母系成员(3个血压异常和1个血压正常者)和3名遗传背景相同的对照者建立了传代淋巴细胞系,利用共聚焦显微镜评价VDAC在携带mtDNA A4263G突变的高血压患者细胞线粒体钙循环中的作用. 结果 与正常对照者淋巴细胞比较,突变细胞株线粒体内钙荧光强度及线粒体膜电势(Δψm)降低,加入苍术苷(线粒体通道蛋白开放剂)后正常者线粒体内钙荧光强度增加,而突变携带者没有明显改变,但两者Δψm均降低,加入环孢素A(CsA)后可以抑制苍术苷作用. 结论 线粒体VDAC功能异常导致mtDNA A4263G突变携带者细胞线粒体对钙通透性增加,Δψm降低,加入苍术苷进一步导致Δψm降低,加入CsA后可以抑制苍术苷作用.     

线粒体外膜电压依赖阴离子通道在携带mtDNA A4263G突变的细胞株凋亡中的作用

目的: 研究线粒体外膜电压依赖的阴离子通道（voltage-dependent anion channel,VDAC）在携带线粒体DNA（mitochondrial DNA,mtDNA）A4263G突变的细胞株凋亡中的作用。方法: 对该家系的4名母系成员（3名血压异常者,1名血压正常者）和3名遗传背景相同的对照者建立了传代淋巴细胞系。采用流式细胞仪检测线粒体膜电势;用激光共聚焦显微镜观测VDAC与Bax蛋白结合的情况。结果: VDAC及凋亡相关蛋白Bax在携带mtDNA A4263G的细胞株中重表达增高,而淋巴细胞sKCa通道的表达没有明显差异;mtDNA A4263G突变携带者的线粒体膜电势与正常者比较平均降低32%（P<0.05）;而加入环孢霉素A（CsA为VDAC拮抗剂）后,线粒体膜电势升高,与正常者之间的差异消失。携带突变者线粒体外膜的VDAC可与Bax蛋白结合,而正常对照者二者没有结合,在加入CsA后,可抑制突变者线粒体外膜VDAC与Bax蛋白的结合。结论: 线粒体VDAC表达异常可导致mtDNA A4263G携带突变的细胞株凋亡增加。     

线粒体融合蛋白2在心血管疾病中的研究现状

线粒体是一个处于不断地融合与分裂过程中的动态细胞器。线粒体融合蛋白2(Mfn2)作为广泛分布于线粒体外膜和线粒体结合内质网膜上具有多重功能的蛋白,参与维持正常细胞功能。除了参与线粒体融合外,Mfn2还能够调节线粒体代谢、促进损伤线粒体的自噬、增强线粒体与内质网交流、维持内质网功能及通过调控线粒体外膜通透性和渗透性钙转运孔道的启闭参与细胞死亡过程等。另外,Mfn2基因还可通过调控Ras-Raf-ERK/MAPK和Ras-PI3K-Akt信号通路分别参与调控血管平滑肌细胞的增殖和凋亡过程。Mfn2的这一系列重要的生物学功能有助于其参与高血压、肺动脉高压、动脉粥样硬化、急性缺血/再灌损伤、扩张性心肌病、心肌肥大、心衰和肥胖糖尿病等多种心血管疾病的发生发展过程。研究Mfn2与心血管疾病的相关性也许能为临床提供一个心血管疾病潜在治疗的靶点。因此,本文将综述Mfn2在心血管疾病相关研究中的现状。     

线粒体质量控制与血管衰老

衰老是心血管疾病的独立危险因素,线粒体在衰老过程中的核心作用被广泛认同。近年来研究发现进化上保守的线粒体质量控制在血管生理和病理生理中发挥重要作用。细胞线粒体质量控制机制包括线粒体自噬、生物合成及动力学(融合/分裂),这些细胞过程通过清除衰老及损伤的线粒体、补充新的线粒体成分、调控线粒体更新维持线粒体数量与质量的稳定。现综述线粒体质量控制异常在血管衰老及衰老相关心血管疾病中的作用。     

H.pylori对胃癌细胞线粒体外膜蛋白VDAC1表达的影响

目的观察幽门螺杆菌(H.pylori)作用于胃癌细胞后线粒体外膜蛋白VDAC1 mRNA及蛋白的表达变化,探讨H.pylori通过线粒体途径致凋亡的分子机制。方法H.pylori分别作用于胃癌细胞0、12、24、48 h后,收集细胞,应用RT-PCR和Western blot法检测各时相点VDAC1 mRNA和蛋白表达变化。结果H.pylori与胃癌细胞共培养12 h后,VDAC1 mRNA及蛋白的表达增加,24 h增加更明显,48 h达到高峰。VDAC1 mRNA及蛋白各时相点的表达量明显高于对照组(P<0.05)。结论H.pylori可能通过上调胃癌细胞线粒体外膜蛋白VDAC1 mRNA及蛋白的表达,引起线粒体外膜通透性改变,导致凋亡发生。     

线粒体动力学、线粒体自噬和心血管疾病

线粒体是一种动态的细胞器,通过响应各种代谢和环境的信号, 分裂和融合改变其形态和结构,从而维持细胞的正常功能。它们短暂而快速的形态变化对于细胞周期、免疫、凋亡和线粒体自噬的质量控制等许多复杂的细胞过程至关重要。线粒体自噬与线粒体质量控制密切相关,通过将受损的功能障碍的线粒体转运到溶酶体进行降解,促进心肌细胞受损线粒体的更新,并有效地抑制功能障碍线粒体的积累。由于心脏作为一个复杂而高耗能的器官,心肌细胞严重地依赖线粒体氧化代谢过程作为其能量和营养供应的来源。许多研究表明,线粒体融合、分裂和线粒体自噬的诸多影响和调控功能的因子都与各种心血管疾病有关,维持线粒体的功能和其完整性对正常心肌细胞的运行是至关重要的。在这篇的综述中,我们将重点概述一下线粒体的融合、分裂和线粒体自噬的诸多调控因子与心血管疾病的最新研究进展。     

线粒体相关内质网膜:心血管疾病治疗的新靶点

线粒体相关内质网膜是指内质网和线粒体之间高度动态的紧密连接部分,参与维持内质网和线粒体的正常功能,与细胞脂质代谢、钙稳态、线粒体动力学、自噬和凋亡、内质网应激和炎症等密切相关。研究显示线粒体相关内质网膜功能异常或者数量和结构改变参与心血管疾病的发生发展。本文总结了线粒体相关内质网膜的功能,阐述了其在心血管疾病中的作用及可能机制,为线粒体相关内质网膜成为心血管疾病治疗的新靶点提供理论参考。     

心肌线粒体能量代谢在心血管疾病中的研究进展

目前心血管疾病已成为全球人类死亡的主要原因之一,线粒体作为三大营养物质经三羧酸循环产生ATP的主要场所,在心血管疾病的发生、进展过程中起着巨大影响作用。本文从心肌线粒体的能量代谢功能、相关调控途径、与心血管疾病的关系以及治疗药物方面入手,在心肌线粒体代谢方面为治疗心血管疾病提供思路与方向。     

心血管疾病治疗的靶点——线粒体ATP敏感性钾通道的研究进展

线粒体是心肌保护的重要靶器官。随着对心血管疾病机制研究的深入,线粒体ATP敏感性钾通道被认为是治疗心肌损伤性疾病的潜在靶点。它是细胞线粒体内一种重要离子通道,其结构复杂,功能多样,在细胞的生理病理过程中起着重要的作用,这一通道保护心肌的机制主要涉及氧化应激、钙超载、细胞凋亡及膜电位的变化等方面。本研究就线粒体ATP敏感性钾通道的结构及其心肌保护机制作一综述。     

内质网–线粒体交互在心血管疾病中的作用研究进展

线粒体和内质网的稳态在维持心血管正常功能中发挥重要作用,线粒体或内质网的结构功能异常参与了众多心血管疾病的发生发展。近年来研究发现线粒体与内质网存在物理和功能的交互,其交互作用调控线粒体、内质网功能,进而影响心肌细胞和平滑肌细胞的线粒体动力学平衡、钙转运及磷脂合成和转运。内质网–线粒体交互异常被认为是冠心病、心力衰竭、肺动脉高压和动脉粥样硬化等心血管疾病的关键机制。因此,理解内质网-线粒体交互机制可为预防和改善心血管疾病提供崭新靶点。     

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.     

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.     

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.     

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.