4,4’-二异硫氰基芪-2,2’-二磺酸对大鼠缺血再灌注损伤的影响及机制

目的探讨广谱氯离子通道阻滞剂4,4’-二异硫氰基芪2,2’-二磺酸(DIDS)对大鼠缺血再灌注损伤心肌细胞凋亡的影响及其机制。方法雄性SD大鼠36只随机分为3组:缺血再灌注组(A组)、DIDS处理组(B组)和LY294002预处理组(C组)。伊文兰和TTC染色测定心肌梗死范围,TUNEL方法定性和定量检测心肌细胞凋亡指数,Western blot测定蛋白激酶B(Akt)的表达。结果与A组比较,B组心肌梗死范围和心肌细胞凋亡指数明显降低[(38.8±7.7)% vs (54.2±10.8)%,(8.9±1.8)% vs (17.6±3.5)%.P<0.01];磷酸化Akt表达水平明显增加(P<0.01)。与A组比较,C组梗死面积、凋亡指数无明显减小,磷酸化Akt水平无明显变化(P>0.05)。结论 DIDS能够抑制大鼠缺血再灌注所致的心肌细胞损伤,可能是通过信号分子磷脂酰肌酶三羟基激酶/Akt的调节。     

PTEN在缺血后处理对糖尿病缺血再灌注心肌失敏感性中的作用及机制

目的探讨PTEN在糖尿病心肌缺血再灌注及后处理中的作用。方法 SD大鼠117只随机分为非糖尿病(NDM)组39只和糖尿病(DM)组78只,其中NDM组分为假手术(NDM+S)亚组、缺血再灌注(NDM+IR)亚组和缺血后处理(NDM+IPo)亚组;DM组分为假手术(DM+S)亚组、缺血再灌注(DM+IR)亚组、缺血后处理(DM+IPo)亚组、PTEN抑制剂双过氧钒(BPV)+假手术(B+DM+S)亚组、BPV+缺血再灌注(B+DM+IR)亚组和BPV+缺血后处理(B+DM+IPo)组。建立心肌缺血再灌注模型,BPV缺血前1h静脉注射。免疫组织化学染色法分析心肌PTEN、磷脂酰肌醇3激酶(PI-3K)、蛋白激酶B(p-Akt)的表达;TTC法检测心肌梗死面积;TUNEL法检测心肌细胞凋亡;光镜下观察心脏组织病理结果。结果与NDM+IR亚组比较,NDM+IPo亚组心肌PTEN表达减少[(0.130±0.024)vs(0.148±0.023),P0.05],PI-3K和p-Akt表达增高[(0.142±0.027)vs(0.112±0.020);(0.137±0.020)vs(0.115±0.021),P0.05],心肌细胞凋亡指数及心肌梗死面积减少[(16.69±1.90)%vs(20.77±0.10)%;(35.02±3.11)%vs(41.10±2.07)%,P0.05]。与DM+IR亚组比较,DM+IPo亚组心肌PTEN、PI-3K、p-Akt表达,心肌细胞凋亡指数及心肌梗死面积均无明显改变(P0.05);与DM+S、DM+IR、DM+IPo亚组比较,BPV干预各亚组心肌PI-3K和p-Akt表达均升高,心肌细胞凋亡指数及心梗面积均减少(P0.05)。结论糖尿病心肌缺血再灌注期间心肌PTEN高表达是造成PI-3K/Akt信号通路失活的重要因素,可能导致IPo对心肌IRI的保护作用丧失。     

高压氧预处理对正常和糖尿病大鼠缺血再灌注心肌细胞凋亡的影响

目的 探讨高压氧预处理对正常和糖尿病大鼠缺血再灌注心肌细胞凋亡及Bcl-2和Bax蛋白的影响.方法 雄性Wistar大鼠75只,随机分为正常大鼠对照组,正常大鼠缺血-再灌注组,正常大鼠高压氧预处理组,糖尿病大鼠对照组,糖尿病大鼠缺血-再灌注组,糖尿病大鼠高压氧预处理组,检测各组心肌凋亡及心肌Bax、Bcl-2蛋白表达.结果 ①正常大鼠高压氧预处理组凋亡指数与正常大鼠缺血-再灌注组相比[(33.15±4.36)％vs(41.72±3.47)％],糖尿病大鼠高压氧预处理组凋亡指数与糖尿病大鼠缺血-再灌注组相比[(41.69±5.79)％vs( 52.73±6.71)％]均明显降低,有统计学差异(P＜0.05).②正常大鼠高压氧预处理组Bax蛋白灰度值与正常大鼠缺血-再灌注组相比[(170.17±7.35)vs(157.50±8.12)],糖尿病大鼠高压氧预处理组Bax蛋白灰度值与糖尿病大鼠缺血-再灌注组相比[(141.17±6.77) vs (134.0±4.73)]均明显降低,有统计学差异(P＜0.05).③正常大鼠高压氧预处理组Bcl-2蛋白灰度值与正常大鼠缺血-再灌注组相比[(158.67±7.69) vs (171.83±8.66)],糖尿病大鼠高压氧预处理组Bcl-2蛋白灰度值与正常大鼠缺血-再灌注组相比[(166.0±10.53)vs(183.33±9.15)]相比均明显增高,有统计学意义(P＜0.05).结论 高压氧预处理对正常及糖尿病大鼠均有抗心肌细胞凋亡的作用,但对正常大鼠保护作用更强,其保护机制可能与下调Bax蛋白表达,上调Bcl-2蛋白表达有关.     

庚醇和甘草次酸对大鼠心肌致死性再灌注损伤的保护作用

目的:研究缺血前给予庚醇和甘草次酸能否预防大鼠心肌致死性再灌注损伤,包括心肌细胞坏死和凋亡,并观察其对心律失常的影响. 方法:制作Langendorf心脏灌流模型,随机分为正常灌注组(SO)、缺血再灌注组(IR)、庚醇组(HT)和甘草次酸组(GA).于整体缺血30 min后再灌注2 h.应用四氮硝基唑蓝(nitroblue tetraxolium,NBT)测定心肌梗死面积,脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(terminal-deoxynucleotidyl transferase mediated nick end labeling,TUNEL)检测心肌细胞凋亡,Curtis和Walker心律失常评分系统评价心律失常严重程度.结果:与SO组相比,IR组心律失常评分增加(0.26±0.5对2.86±1.46);心肌梗死范围明显扩大,凋亡细胞数显著增加(0.35±0.26)%对(35±6.6)%,P＜0.01.与IR组比较,HT和GA组心肌梗死面积明显减轻,分别为(38±9.7)%对(9±2.9)%对(16±7.0)%,P＜0.05;凋亡细胞数也显著减少,分别为(35±6.6)%对(17±4.6)%对(22±1.2)%,但心律失常发生无明显减少或增加. 结论:缺血前给予间隙连接抑制剂庚醇和甘草次酸可明显减轻心肌致死性再灌注损伤,表现为缩小心肌梗死范围和减少心肌细胞凋亡,但对心律失常的发生无影响.     

微小核糖核酸-223-3p对心脏缺血/再灌注损伤后心脏重构的影响

目的:探讨微小核糖核酸-223-3p(miR-223)在小鼠心脏缺血/再灌注损伤(I/R)导致心脏重构中的作用及对心肌细胞氧化应激的影响。方法:随机选取9只,雄性,miR-223缺陷小鼠,为miR-223缺陷组;野生型C57BL/6J,雄性小鼠,9只,为对照组,均结扎冠状动脉前降支30min后拔出结扎线复制I/R模型。28d后测量小鼠体质量、心脏重量及胫骨长度,计算心脏重量与体质量比和心脏重量与胫骨长度比。收取心脏组织进行切片,Masson染色检测小鼠心脏肥大和纤维化情况。体外培养H9C2心肌细胞,用miR-223 mimic转染H9C2使其过表达miR-223后,缺氧/复氧刺激H9C2心肌细胞,检测活性氧自由基(ROS)的水平。结果:与对照组小鼠相比,术后28d miR-223缺陷组小鼠心脏重量与体质量比和心脏重量与胫骨长度比明显增高(均P0.01),心脏纤维化增加[(5.16±2.11)vs.(13.19±1.96)%,P0.05];miR-223 mimic转染心肌细胞后,miR-223的表达水平上调218.59倍;体外培养心肌细胞miR-223过表达能显著降低ROS的释放[(22.42±0.78)vs.(18.62±0.62)%,P0.01]。结论:microRNA-223-3p可能通过抑制心肌细胞氧化应激减轻心脏缺血/再灌注损伤后心脏重构。     

庚醇和甘草次酸对大鼠心肌致死性再灌注损伤的保护作用

目的:研究缺血前给予庚醇和甘草次酸能否预防大鼠心肌致死性再灌注损伤,包括心肌细胞坏死和凋亡,并观察其对心律失常的影响。方法:制作Langendorf心脏灌流模型,随机分为正常灌注组(SO)、缺血再灌注组(IR)、庚醇组(HT)和甘草次酸组(GA)。于整体缺血30min后再灌注2h。应用四氮硝基唑蓝(nitroblue tetraxolium,NBT)测定心肌梗死面积,脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(terminal-deoxynucleotidyl transferase mediated nick end labeling,TUNEL)检测心肌细胞凋亡,Curtis和Walker心律失常评分系统评价心律失常严重程度。结果:与SO组相比,IR组心律失常评分增加(0.26±0.5对2.86±1.46);心肌梗死范围明显扩大,凋亡细胞数显著增加(0.35±0.26)%对(35±6.6)%,P<0.01。与IR组比较,HT和GA组心肌梗死面积明显减轻,分别为(38±9.7)%对(9±2.9)%对(16±7.0)%,P<0.05;凋亡细胞数也显著减少,分别为(35±6.6)%对(17±4.6)%对(22±1.2)%,但心律失常发生无明显减少或增加。结论:缺血前给予间隙连接抑制剂庚醇和甘草次酸可明显减轻心肌致死性再灌注损伤,表现为缩小心肌梗死范围和减少心肌细胞凋亡,但对心律失常的发生无影响。     

缺血预适应对兔急性心肌梗死早期心电图改变的影响

目的通过兔缺血预适应模型,观察缺血预适应(IPC)对兔急性心肌梗死早期心电图改变及梗死面积的影响。方法 40只大耳白兔随机等分为IPC组和非IPC,分别制造缺血预适应模型和急性心肌梗死模型。(1)对比分析两组缺血期:T波改变、ST段改变、R波振幅、缺血性J波、心律失常和梗死面积。(2)对比分析IPC组组内第一次预适应与三次预适应后缺血期前4项指标改变。结果(1)IPC组较非IPC组:T波增高幅度降低[缺血后40秒(0.40±0.11)mV vs(0.46±0.12)mV,P0.05];J波发生率显著降低(0 vs 35%,P0.01);室速、室颤发生率显著降低(分别为10.5%vs 30%和0 vs 15%,均P0.05);心肌梗死面积减少[(30.8±6.6)%vs(35.3±6.9)%,P0.05]。(2)IPC组组内三次预适应后缺血期比较第一次预适应缺血期:T波增高幅度降低[缺血后40 s(0.40±0.1)mV vs(0.46±0.1)mV,P0.05];,波发生率显著降低(0 vs 25%,P0.01)。结论心肌缺血预适应可以降低急性心肌缺血早期T波改变振幅,减少J波发生率、减少恶性室性心律失常,缩小梗死面积,保护缺血心肌。     

极化液对缺血/再灌大鼠心肌细胞死亡及心脏功能的影响:胰岛素的关键作用

目的　探讨葡萄糖 胰岛素 钾极化液 (GIK)对心肌缺血 /再灌 (MI/R)后心肌细胞死亡(坏死和凋亡 )及心脏功能的影响 ,并比较和分析GIK各组分在其中的作用。方法　制备大鼠MI/R模型 ,分别用生理盐水、GIK、葡萄糖 钾液 (GK)或胰岛素干预分组。观察动脉血压、血糖、左室压等的变化 ,再灌注结束后检测心肌梗死或提取DNA检测心肌细胞凋亡。结果　MI/R造成明显的心脏功能障碍、心肌梗死和缺血区细胞凋亡。GIK与胰岛素 (而非GK)具有相似的减轻再灌注心肌损伤作用 ,包括减少心肌梗死范围 [(41 3± 8 3) %和 (39 6± 8 6) %比对照组 (54 4± 1 0 4) % ,q =4 34和q=4 90 ,P值均 <0 0 5]、减弱DNA梯带形成及促进再灌后心脏收缩 /舒张功能恢复。结论　GIK可减少心肌梗死、促进缺血心脏功能恢复 ,胰岛素可能通过抑制缺血心肌细胞凋亡在GIK心肌保护中发挥关键作用。     

大剂量当归预适应抗心肌缺血再灌注后心肌细胞凋亡的机制

目的观察大剂量当归水煎液预适应对缺血再灌注(IR)大鼠心肌细胞凋亡及心肌组织Bcl-2及Bax蛋白表达的影响。方法应用离体灌流大鼠心脏,复制大鼠心肌IR与缺血预适应(IPC)模型,并以不同大剂量当归水煎液灌胃6 w后,取大鼠心脏进行离体灌注,复制当归IPC模型,以TTC法测定心肌梗死面积,以Tunel法检测细胞凋亡,Western印迹法检测Bcl-2及Bax蛋白表达。结果大剂量当归水煎液预适应能有效降低IR大鼠心肌梗死面积,降低心肌细胞的凋亡率,并增加心肌组织Bcl-2的表达而抑制Bax的表达,且呈现明显剂量-效应关系(P0.05,P0.01)。结论大剂量当归水煎液预适应可增加心肌组织Bcl-2的表达而抑制Bax的表达,从而减少IR大鼠心肌细胞的凋亡,对IR大鼠心肌具有明显保护作用。     

缺血再灌注时心肌细胞凋亡情况及去甲肾上腺素预处理对其影响

目的　探讨微量去甲肾上腺素预处理对大鼠缺血再灌注心肌细胞凋亡的影响。方法　大鼠在体缺血再灌注 (I/ R)模型 ,分别以缺血前去甲肾上腺素预处理 (NE- P) ,缺血预处理 (IP) ;采用末端脱氧核苷酸转换酶介导的生物素平移缺口末端标记技术 (TUNEL )检测各组心肌细胞凋亡情况及心肌梗死范围。结果　 I/ R组细胞凋亡率 (43.33%± 4.92 % )较高 ,NE- P组及 IP组虽然也有一定的心肌细胞凋亡率 :2 5.2 4 %± 1 .56% ,2 4 .44%± 2 .96% ,但较 I/ R组明显降低 (P<0 .0 0 1 )。 IP组及 NE- P组心肌梗死范围较 I/ R组明显减少 ,IP组及 NE- P组两项指标无显著差异。结论　心肌缺血再灌注损伤可诱发心肌细胞凋亡 ,NE- P能明显减少缺血再灌注诱导的心肌细胞凋亡的发生率 ,能明显减少心肌梗死范围 ,减轻缺血再灌注损伤 ;NE- P减少心肌梗死范围、减轻缺血再灌注损伤的机制可能与其能明显减少心肌细胞凋亡有关。     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

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.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

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.     

Language of CTO interventions – Focus on hardware

The knowledge of variety of chronic total occlusion (CTO) hardware and the ability to use them represents the key to success of any CTO interventions. However, the multiplicity of CTO hardware and their physical character and the terminology used by experts create confusion in the mind of an average interventional cardiologist, particularly a beginner in this field. This knowledge is available but is scattered. We aim to classify and compare the currently used devices based on their properties focusing on how physical character of each device can be utilized in a specific situation, thus clarifying and simplifying the technical discourse.