氧化型和正常极低密度脂蛋白对猪主动脉平滑肌细胞脂类堆积的不同影响

为了观察氧化型及正常极低密度脂蛋白对血管平滑肌细胞内脂类堆积的不同影响，探索平滑肌细胞摄取氧化型极低密度脂蛋白的受体途径，用２００ｍｇ／Ｌ的氧化型及正常极低密度脂蛋白与猪主动脉平滑肌细胞温有４８ｈ后，细胞内甘油三脂含量分别为对照组的３．２倍和１０．６倍（Ｐ〈０．０１），且两个实验组之间相比，差异也有显著性意义（Ｐ〈０．０１），细胞内总胆固醇明显升高（Ｐ〈０．０５），但是两个实验组之间无显著差异（Ｐ     

糖尿病大鼠糖基化终产物与主动脉细胞外基质成分的关系

为了观察富含胆固醇的脂蛋白对兔主动脉平滑肌细胞脂类堆积的影响及机制,用富含胆固醇的脂蛋白（β－ 极低密度脂蛋白、正常低密度脂蛋白和氧化型低密度脂蛋白） 与兔主动脉平滑肌细胞温育４８ ｈ 后,发现β－ 极低密度脂蛋白、正常低密度脂蛋白和氧化型低密度脂蛋白都能促进平滑肌细胞内总胆固醇和甘油三酯堆积,以β－ 极低密度脂蛋白的作用更显著。乳铁蛋白作为低密度脂蛋白受体相关蛋白的一种特异配体,当它与上述脂蛋白共同与平滑肌细胞温育后,发现乳铁蛋白对脂蛋白所致的平滑肌细胞内脂质堆积有抑制作用。乳铁蛋白与标记的β－ 极低密度脂蛋白、正常低密度脂蛋白和氧化型低密度脂蛋白的竞争结合实验也进一步发现乳铁蛋白可明显竞争β－ 极低密度脂蛋白、正常低密度脂蛋白、氧化型低密度脂蛋白与平滑肌细胞的结合,且对β－ 极低密度脂蛋白的竞争抑制作用尤为明显。提示β－ 极低密度脂蛋白、正常低密度脂蛋白和氧化型低密度脂蛋白可能主要通过低密度脂蛋白受体相关蛋白介导进入平滑肌细胞,导致平滑肌细胞内脂质堆积。     

氧化型低密度脂蛋白在人外周血单核巨噬细胞中的代谢

为探讨氧化型低密度脂蛋白在人外周血单核巨噬细胞中的代谢及其致动脉粥样硬化的机制，使用放射配基法观察了两种低密度脂蛋白在单核巨噬细胞中的代谢情况，并测定了细胞内胆固醇含量的变化。结果发现，人外周血单核巨噬细胞通过受体途径代谢低密度脂蛋白。该受体可饱和，最大结合量（Bmax）为274μg／g细胞蛋白，解离常数为35.7mg／L。低密度脂蛋白经氧化修饰后，人外周血单核巨噬细胞对其结合、摄取和降解均显著增加；与氧化型低密度脂蛋白共同孵育的人外周血单核巨噬细胞内总胆固醇含量明显高于低密度脂蛋白组。以上结果提示，低密度脂蛋白经氧化修饰后在人外周血单核巨噬细胞内的代谢途径发生改变并导致细胞内总胆固醇的堆积，促进了动脉粥样硬化的发生。     

氧化型脂蛋白诱导血管平滑肌细胞表达单核细胞趋化蛋白-1

为了解脂蛋白对平滑肌细胞的单核细胞趋化蛋白-1mRNA和蛋白表达的影响，在牛主动脉平滑肌细胞培养基中分别加入低密度脂蛋白、氧化型低密度脂蛋白、极低密度脂蛋白和氧化型极低密度脂蛋白，培养24h，用异硫氰酸胍法提取细胞的总RNA，用γ-32P末端标记的单核细胞趋化蛋白-1的寡核苷酸探针进行狭缝杂交分析，检测平滑肌细胞的单核细胞趋化蛋白-1mRNA的表达。同时用夹心酶联免疫吸附试验检测条件培养基中单核细胞趋化蛋白-1的蛋白含量。结果发现。培养的牛主动脉平滑肌细胞能表达单核细胞趋化蛋白-1mRNA及蛋白，氧化型低密度脂蛋白和氧化型极低密度脂蛋白使其单核细胞趋化蛋白-1mRNA的表达明显增强，同时也使其条件培养基中单核细胞趋化蛋白-1的蛋白水平增加，而低密度脂蛋白和极低密度脂蛋白仅使平滑肌细胞中单核细胞趋化蛋白-1mRNA和蛋白的表达轻度增加。提示氧化型低密度脂蛋白和氧化型极低密度脂蛋白能诱导平滑肌细胞表达高水平的单核细胞趋化蛋白-1。     

硫酸乙酰肝素蛋白聚糖及肝素对巨噬细胞脂质蓄积的抑制作用

用苏丹Ⅳ染色观察巨噬细胞内脂质聚积的变化；通过酶－荧光法检测巨噬细胞内胆固醇含量并检测125Ⅰ标记氧化型低密度脂蛋白降解量来反映巨噬细胞清道夫受体的活性，以探讨硫酸乙酸肝素蛋白聚糖及肝素对巨噬细胞脂质蓄积的影响及机制。结果发现，氧化型低密度脂蛋白（100mg／L）组巨噬细胞的胞浆内可见较多苏丹Ⅳ着色红染颗粒，氧化型低密度脂蛋白（100mg／L）十硫酸乙酰肝素蛋白聚糖（15．5mg／L）组0及氧化型低密度脂蛋白（100mg／L）十肝素（200mg／L）组巨噬细胞内红色颗粒明显少于氧化型低密度脂蛋白组；氧化型低密度脂蛋白十硫酸乙酰肝素蛋白聚糖组及氧化型低密度脂蛋白十肝素组巨噬细胞内总胆固醇和胆固醇酯的含量明显低于氧化型低密度脂蛋白组（P＜0．05，P＜0．01）；硫酸乙酰肝素蛋白聚糖组及肝素组125Ⅰ标记的氧化型低密度脂蛋白降解量均低于对照组。结果提示，硫酸乙酰肝素蛋白聚糖和肝素可能是通过下调清道夫受体活性减少了巨噬细胞对氧化型低密度脂蛋白的摄取而抑制脂质在巨噬细胞内的聚集和泡沫细胞的形成。     

肝细胞膜低密度脂蛋白受体酶联免疫测定法的建立

实验建立了检测肝细胞膜低密度脂蛋白受体的抗配体抗体酶联免疫吸附测定法．测定中，固相膜受体蛋白量由包放前后膜蛋白浓度差值计算确定；低密度脂蛋白结含量按双抗体夹心法制作的低密度脂蛋白标准曲线确定，膜蛋白非村异吸附则用与酶联抗体来源相同的同种动物血浆低密度脂蛋白平行抑制试验消除．兔肝细胞膜低密度脂蛋白受体结合活性经Scatchard作图，Kd＝13．6mg／L，Bmax＝124μg／g膜蛋白（n=5）．测定结果说明建立的方法安全可靠，能反映受体的结合活性，在高脂血症及心血管病的研究中具有广泛的应用价值．本研究还对选择确定受体包被浓度、酶交联物稀释度等的棋盘滴定方法作了详细介绍和讨论．     

氧化型低密度脂蛋白对血管平滑肌细胞磷酸酶PTEN活性的影响

为探讨氧化型低密度脂蛋白促血管平滑肌细胞增殖的细胞内信号转导机制，将兔血管平滑肌细胞分为对照组、低密度脂蛋白组和氧化型低密度脂蛋白组。以细胞计数和噻唑蓝比色法测定细胞增殖能力，Western blot定量与细胞骨架蛋白同源在10号染色体有缺失的磷酸酶（PTEN）表达水平，免疫沉淀和特异底物diC16PIP3脱磷酸绿色试剂法检测该磷酸酶活性。实验发现氧化型低密度脂蛋白（50mg/L)可使细胞计数及噻唑蓝比色吸光值分别增加1．78和3．21倍，而低密度脂蛋白（50mg/L)无明显作用。各浓度低密度脂蛋白及氧化型低密度脂蛋白对该磷酸酶蛋白表达水平均无显著影响。氧化型低密度脂蛋白对PTEN活性的抑制在20－50mg/L范围内呈浓度依赖性。时间曲线表现为10min作用最强，并可持续达24h(与对照组比较，均P＜0．01）。结果提示；氧化型低密度脂蛋白可能通过对负性调节蛋白PTEN磷酸酶的凶制而发挥促进血管平滑肌细胞增殖功能。     

巨噬细胞修饰低密度脂蛋白对细胞受体活性的影响及前列腺素E_2的作用

为研究低密度脂蛋白经细胞修饰后对细胞受体的影响及前列腺素E2的作用，利用免疫细胞化学和生物亲和素-酶联免疫吸附法分别检测小鼠腹腔巨噬细胞清道夫受体、小鼠皮肤纤维母细胞低密度脂蛋白受体的结合活性，结果发现修饰组的巨噬细胞胞浆及胞膜有强阳性黄褐色颗粒，而药物组仅中度着色；修饰组低密度脂蛋白与其受体结合量（54±13μg／g细胞蛋白）较对照组（144±μg／g细胞蛋白）显著下降（P＜0．01）；药物组受体结合量（100±11μg／g细胞蛋白）较修饰组明显提高（P＜0．05）。表明细胞修饰低密度脂蛋白能够刺激清道夫受体活性，抑制低密度脂蛋白受体活性；前列腺素E2（20mg／L）可对抗细胞修饰低密度脂蛋白对此二种受体的作用。     

高密度脂蛋白对氧化型低密度脂蛋白抑制的血管平滑肌细胞一氧化氮释放的影响

为观察高密度脂蛋白是否能拮抗氧化型低密度脂蛋白对血管平滑肌细胞释放一氧化氮的抑制作用，培养了人脐动脉平滑肌细胞并用脂多糖和γ-干扰素诱导一氧化氮的释放。应用GRIESS试剂测定细胞培养基中亚硝酸盐的含量．以免疫组织化学染色和逆转录--聚合酶链反应分析诱导型一氧化氮合酶基因的表达。结果发现，氧化型低密度脂蛋白可使脂多糖和γ-干扰素诱导的平滑肌细胞一氧化氮合酶及其mRNA水平下降、抑制一氧化氮释放。而高密度脂蛋白能拮抗氧化型低密度脂蛋白对平滑队细胞释放一氧化氮的抑制作用。0．25g／L高密度脂蛋白即能显著增加一氧化氮的释放（P＜0．05），高密度脂蛋白浓度达到1．5g／L可使得一氧化氮的释放增加4．5倍。结果表明，高密度脂蛋白能提高一氧化氮合酶基因表达水平，促进一氧化氮的释放。高密度脂蛋白的作用具有浓度效应。     

普罗布考抑制大鼠血管平滑肌细胞周期素D1蛋白表达和G1→S转换

目的研究普罗布考是否通过阻滞细胞周期抑制平滑肌细胞增殖。方法首先用普罗布考和氧化型低密度脂蛋白与平滑肌细胞共同孵育。然后用MTT法和细胞计教法测定细胞增殖，用流式细胞术观察细胞周期，最后用蛋白印迹测蛋白表达。结果MTT法和细胞计数法显示25～100mg／L氧化型低密度脂蛋白都能刺激平滑肌细胞增殖，效应呈浓度依赖性，普罗布考能显著抑制氧化型低密度脂蛋白所诱导的细胞增殖，效应呈浓度和时间依赖性。流式细胞术分析表明普罗布考增加了G0/G1细胞比例达28.6％（P〈0．01，n=3），减少S期细胞比例达83．5％（P〈0.01，n=3）。蛋白印迹结果显示氧化型低密度脂蛋白诱导细胞周期素D1蛋白表达，高峰在6～12h，普罗布考显著减少周期素D1蛋白表达，在6h和12h分别减少达26％和23％（P均〈0.01，n=3）。结论普罗布考显著抑制氧化型低密度脂蛋白所诱导的细胞增殖，其抗增殖活性与普罗布考下调周期素D1蛋白表达，从而阻滞细胞由C0/G1期向S期转换有关。     

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.     

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.     

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.     

Serological survey of HIV and syphilis in pregnant women in Madagascar

Objectives Peripartal transmission of human immunodeficiency virus (HIV) and Treponema pallidum, the causative agent of syphilis, leads to severe consequences for newborns. Preventive measures require awareness of the maternal infection. Although HIV and syphilis testing in Madagascar could be theoretically carried out within the framework of the national pregnancy follow‐up scheme, the required test kits are rarely available at peripheral health centres. In this study, we screened blood samples of pregnant Madagascan women for HIV and syphilis seroprevalence to estimate the demand for systemic screening in pregnancy. Methods Retrospective anonymous serological analysis for HIV and syphilis was performed in plasma samples from 1232 pregnant women that were taken between May and July 2010 in Ambositra, Ifanadiana, Manakara, Mananjary, Moramanga and Tsiroanomandidy (Madagascar) during pregnancy follow‐up. Screening was based on Treponema pallidum haemagglutination tests for syphilis and rapid tests for HIV, with confirmation of positive screening results on line assays. Results Out of 1232 pregnant women, none were seropositive for HIV and 37 (3%) were seropositive for Treponema pallidum. Conclusions Our findings are in line with previous studies that describe considerable syphilis prevalence in the rural Madagascan population. The results suggest a need for screening to prevent peripartal Treponema pallidum transmission, while HIV is still rare. If they are known, Treponema pallidum infections can be easily, safely and inexpensively treated even in pregnancy to reduce the risk of transmission.     

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.