高密度脂蛋白与冠心病的关系

脂质代谢紊乱与冠心病的关系,长期以来虽受广泛重视,但多集中注意低密度脂蛋白(LDL,β脂蛋白)和最低密度脂蛋白(VLDL,前β脂蛋白)浓度升高对动脉粥样硬化的促进作用。近年来,一些研究指出,血浆中的高密度脂蛋白(HDL,α脂蛋白)具有抗动脉粥样硬化的作用。 HDL一般可再分为HDL_2和HDL_3,HDL_2密度为1.063～1.125,含蛋白质40％,脂质60％;HDL_3密度为1.125～1.210,含蛋白质55％,脂质45％。蛋白质中主要为载脂蛋白(又称阿朴蛋白或酶蛋白Apoprotein)A_1和A_2,占90％以上。HDL_2和HDL_3的关系未明。肝脏是合成HDL的主要部位。 HDL是胆固醇正常代谢所必需,它与细胞的游离胆固醇有高度亲和力。在卵磷酯-胆固醇酰基转移酶(LCAT)的参与下,HDL能将肝外组织,包括动脉壁的胆固醇转运至肝脏     

营养和代谢疾病

782786 Ⅳ型高脂蛋白血症患者血浆HDL_2-C含量的研究刘德文山西医药杂志15(1):13～15,1986 对10名正常人及5名Ⅳ型高脂蛋白血症患者进行血凝高密度脂蛋白亚组分中胆固醇的含量研究,结果表明,Ⅳ型患者血浆高密度脂蛋白分子内胆固醇含量(HDL-C)远低于正常组(P<0.001),特别是HDL_2亚组分中胆固醇含量(HDL_2-C)降低更为显著,而HDL_3亚组分内胆固醇含量(HDL_3-C)与正常组无差异,提示Ⅳ型高脂蛋白血症诱发冠心病的原因与血浆HDL_2-C含量降低有关。     

心脏移植后脂蛋白脂酶和肝脂酶活性以及高密度脂蛋白亚成分的改变

动脉粥样硬化是心脏移植病人长期生存的主要障碍,移植后血浆甘油三酯和脂蛋白胆固醇浓度升高可能导致移植心脏粥样硬化。作者比较72例心脏移植病人与51例健康对照者,研究免疫抑制剂对血浆甘油三酯、低密度脂蛋白(LDL)胆固醇、高密度脂蛋白(HDL)胆固醇、HDL亚成分(HDL_2和HDL_3)胆固醇、肝脂酶和脂蛋白脂酶的影响。发现移植组血浆甘油三酯浓度升高80％(P<0.001),LDL胆固醇升高16％(P<0.005),     

人血浆高密度脂蛋白亚类分布与动脉粥样硬化

高密度脂蛋白(HDL)是一类不均一的脂蛋白,各种HDL亚类具有不同而又相关的代谢功能.血浆脂质和载脂蛋白含量变化会影响HDL亚类分布.高甘油三酯血症、高胆固醇血症、特别是混合型高脂血症患者血浆HDL颗粒变小,而且随着血浆甘油三酯、总胆固醇含量的升高,上述变化会更加明显.提示HDL成熟代谢受阻,胆固醇逆向转运减弱.不同的载脂蛋白在HDL合成及代谢中起着各不相同的作用.当血浆apoAⅠ含量增加时,所有的HDL亚类均增加,且大颗粒的HDL2b增加最为明显.ApoAⅡ具有双重功能,有使小颗粒HDL3b、HDL3a以及大颗粒的HDL2b同时增加的作用.血浆apoB100、CⅡ以及CⅢ在HDL组装中具有协同作用,apoAⅠ对抗上述载脂蛋白引起HDL颗粒变小的作用.此外,糖尿病和冠心病患者血浆HDL颗粒呈变小趋势.使用他汀治疗的冠心病患者血浆HDL亚类分布的改善滞后于血浆脂质水平的正常化,表明HDL亚类图谱分析有助于冠心病患者的风险分层.     

非胰岛素依赖型糖尿病(NIDDM)和葡萄糖耐量减退(IGT)患者血浆高密度脂蛋白(HDL)及其亚型的研究

本文用Eder等改良的化学沉淀法,测定95例未经治疗的和87例已经治疗的非胰岛素依赖型糖尿病人(NIDDM),以及86例糖耐量减退患者(IGT)的血浆高密度脂蛋白(HDL)及其亚型HDL_2和HDL_3。结果表明,与正常对照组相比,各组病人的HDL-胆固醇浓度均显著降低;HDL_2-及HDL_3-胆固醇浓度也降低,而HDL_2-胆固醇浓度的下降幅度更大,但HDL及其亚型的胆固醇浓度在三组病人之间无显著差异。国内外文献报告糖尿病大血管并发症可能与血浆HDL及其亚型HDL_2浓度的降低有关。本文结果表明在糖耐量异常的早期,如IGT病人也可能出现HDL水平的异常,临床上应给予高度重视。     

甲腈咪呱和呋喃硝胺对高密度脂蛋白胆固醇的影响

近来报导,在Ⅱ型高脂蛋白血症应用甲腈咪呱可以增加高密度脂蛋白胆固醇(HDL-ch)的浓度。在10名健康受试者中发现,用甲腈咪呱每日1克治疗,4周后其HDL-ch浓度显著增高。本文作者分别对甲腈咪呱每日1克和呋喃硝胺每日30~0毫克治疗时HDL、HDL_2、HDL_3胆固醇的变化进行了观察。     

高密度脂蛋白的研究进展

大量流行病学的调查资料表明,高密度脂蛋白(high density lipoprotehn,HDL)是一种抗动脉粥样硬化的脂蛋白,有报告指出,血清 HDL-胆固醇含量高的人,其寿命也相对较长。因而引起人们对此类脂蛋白的极大兴趣,并对其组成、结构、功能、代谢及其与冠心病的关系等方面进行广泛深入的研究。本文拟就这一领域中近年来与临床关系较密切的进展作简要综述。HDL 的组成成分在超速离心中,密度为1.063～1.200g/ml范围内的脂蛋白部分统称为高密度脂蛋白(HDL)。HDL 不论在密度、颗粒大小和化学组成方面都是极不均一的。从密度上说,它包括2类:即 HDL_2——密度范围为1.063～1.125g/ml 和 HDL_3——密度范围为1.125～1.210g/ml。据新近报告,HDL_2还可分为 HDL_(2a)。和 HDL_(2b)     

血浆HDL水平的影响因素

血浆高密度脂蛋白(HDL)与动脉粥样硬化的发生和发展密切相关。流行病学和实验资料表明,血浆高密度脂蛋白胆固醇(HDL-ch)与冠心病发病率呈负相关;血浆总 HDL 与 HDL 亚组分问并不都成比例,冠心病患者的血浆 HDL 降低主要是 HDL_2的降低,HDL_3无明显变化。血浆 HDL 水平和 HDL 各亚组分的构成比例受许多因素的影响,     

靶向“失功能性”高密度脂蛋白的研究进展

高密度脂蛋白(HDL)是血浆中携运胆固醇的一类主要脂蛋白,正常情况下,HDL具有介导胆固醇逆向转运(RCT)、抗氧化及抗炎、抑血栓形成、促内皮修复等调节血管功能的作用,是机体重要的动脉粥样硬化(As)防御因素。但HDL是在起源、大小、组成及功能上表现极不均一性的脂蛋白颗粒,同时炎症、氧化应激、血脂紊乱、高糖等环境下可引起HDL结构及组分的     

英国妇女饮酒与心血管病危险因素的关系

为了明确妇女饮酒与冠心病某些危险因素的关系,作者研究了饮酒对妇女血浆胰岛素和脂蛋白浓度的影响。对象和方法随机分层选择英格兰东布里斯托尔1048名妇女做为研究对象,年龄25～69岁。根据每天饮料含乙醇的量分成不含乙醇、含乙醇1～10g、11～20g、21～30g和>30g五组。视1～20g为适量饮酒;>30g为大量饮酒者。于空腹采取静脉血,分别测定血浆胰岛素、总胆固醇、总甘油三酯、高密度脂蛋白(HDL)及其亚型HDL_2和HDL_3的胆固醇含量,     

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.     

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.     

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.     

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.