心理应激在高血压病形成和发展中的作用及机制

应激可以兴奋交感神经系统，刺激机体释放多种升血压活性物质，并引发一系列的神经、内分泌、心血管等系统的变化，导致动脉血压持续升高，最终诱发高血压的发生。心理应激作为应激的一种，越来越受到人们的重视，目前它被认为是原发性高血压形成和发展的重要因素。本文综述了近年来心理应激在原发性高血压形成和发展中的作用及其作用机制。     

心理应激在高血压病形成和发展中的作用及机制

应激可以兴奋交感神经系统,刺激机体释放多种升血压活性物质,并引发一系列的神经、内分泌、心血管等系统的变化,导致动脉血压持续升高,最终诱发高血压的发生.心理应激作为应激的一种,越来越受到人们的重视,目前它被认为是原发性高血压形成和发展的重要因素.本文综述了近年来心理应激在原发性高血压形成和发展中的作用及其作用机制.     

下丘脑在紧张应激致高血压发病中的作用

近年来,高血压已上升为临床上危害人们健康的首要因素之一,它是一种发病机制非常复杂的疾病。目前认为,高度紧张应激是现代化快节奏工作、生活环境导致高血压、冠心病与心律失常等心血管疾病发病率上升的重要原因。动物实验也表明,在各种人为的模拟环境应激因素长期作用下,动物可保持持续紧张应激状态,如情绪紧张、恐惧及行为上防备状态,同时伴有血压升高、心率加快、交感神经紧张性加强以及某些内分泌激素水平的变化。久之,升压反应逐渐发展为持续的血压升高,导致中枢心血管调节功能失常,这种环境应激因素长期作用形成的高血压称为应激性高…     

应激性血压升高对大鼠下丘脑肾上腺髓质素水平的影响

目的 探讨应激性血压升高对下丘脑肾上腺髓质素编码基因表达及水平的影响.方法 58只雄性SD大鼠随机分为对照组(n=23)和应激组(n=35),应激组给予噪声或噪声加足底电击随机组合输出刺激制备应激性高血压动物模型.48只动物在实验第1、5、10、15天以及实验结束后5、10天测量尾动脉压后处死(每个时间点对照组和应激组分别为n=3和n=5).分离下丘脑并制备组织匀浆后分别采用逆转录聚合酶链反应检测肾上腺髓质素编码基因表达变化,放射免疫法检测肾上腺髓质素水平变化.另外10只在实验第10天后断头取下丘脑制备冰冻切片,采用免疫组织化学法检测肾上腺髓质素免疫阳性细胞分布变化.结果 应激5天后动物血压开始明显升高,15天达到高峰(156.3±3.3 mmHg比114.0±2.6 mmHg,P<0.01),应激结束10天血压仍维持在较高水平.与对照组相比较,肾上腺髓质素编码基因mRNA表达在应激10天内逐渐上调(第5天0.99±0.05比0.92±0.04,P<0.05;第10天1.26±0.04比0.92±0.04,P<0.01),而后表达下调,在应激第15天仍高于对照组(1.00±0.04比0.92±0.04,P<0.05).应激结束后5天表达仍高于对照组,但差异无统计学意义;与同时间点对照组相比较,肾上腺髓质素水平在应激10天内逐渐增加(第1天1.25±0.22比0.93±0.19,P<0.05;第5天1.69±0.29比0.97±0.21,P<0.01;第10天2.00±0.28比0.94±0.24,P<0.01).应激组(n=5)大鼠下丘脑室旁核区域肾上腺髓质素阳性细胞的光密度明显高于对照组(n=5),由正常的110.21±3.10增加到127.56±3.50(P<0.01),而其他区域无明显变化.结论 应激性血压升高过程中,下丘脑肾上腺髓质素编码基因mRNA表达和肾上腺髓质素水平均发生相应变化,尤其以室旁核明显,提示下丘脑室旁核肾上腺髓质素可能通过维持血压平衡及内环境稳态参与应激致高血压发生的病理生理过程.     

钠盐与慢性应激在高血压中的应用

为对钠盐及应激在高血压中的作用及机制进行探讨，本研究观察（1）慢性应激大鼠的血流动力学及尿钠排泄的变化，（2）单侧肾去神经对二侧肾功能的影响，（3）应激及高盐对动物血压的影响。结果：经慢性应激2周后，大鼠的肾血浆流量（RPF）明显低于对照未应激大鼠（2.90±0.27ml／min／100g，4.02±0.32ml／min/100g,P＜0.01）。左肾去神经后，应激大鼠左侧RPF恢复至正常水平。应激及非应激大鼠尿钠及尿量明显增加，但应激组尿量及尿钠的增加幅度明显大于非应激组。仅经高盐饮食或应激刺激后,血压均未升高。高盐饮食后再给予应激刺激,血压则逐渐升高，第12天达高峰（130.5±15.2vs108.1±22.5mmHg，P＜0.01）。本研究提示慢性应激可以增加肾交感神经张力，使肾脏的排钠功能发生变化，当给予高盐饮食后，可产生高血压。     

老年高血压患者动态血压变化与心率变异性的关系

目前认为血压的短期调节主要是通过交感神经活动的调节实现的，在动脉血压升高时，压力感受器受到刺激，产生反射性心率减慢，血压下降；反之，血压上升。动物实验和人体研究上均获得了同样结论：自主神经功能障碍是高血压患者不能维持正常水平的一个重要原因，高血压初期可能依赖于交感活性增高，血压持续增高后是否继续依赖该机制来维持的报道少见，我们对患者行同步监测24h动态血压（ABPM）和动态心电图，分析自主神经功能在老年高血压患者日常生活中血压的调节作用。     

经导管肾动脉交感神经消融术临床应用的不同观点

肾脏是调节人体血压的重要器官,肾交感传入神经将肾脏感受器的反射信号传导至中枢,再由肾交感传出神经调节血压变化.肾交感神经的活动不仅是短期调节肾动脉血管张力变化,也能够影响肾小管钠水重吸收和肾素的释放.过去几年中,高血压的经导管肾动脉交感神经消融术（RDN）这一新技术逐渐在许多国家的临床应用中被接受,其降压机制为对抗交感神经过度兴奋在维持血压升高中的作用.     

下丘脑在紧张应激致高血压发病中的作用

近年来,高血压已上升为临床上危害人们健康的首要因素之一,它是一种发病机制非常复杂的疾病.目前认为,高度紧张应激是现代化快节奏工作、生活环境导致高血压、冠心病与心律失常等心血管疾病发病率上升的重要原因.动物实验也表明,在各种人为的模拟环境应激因素长期作用下,动物可保持持续紧张应激状态,如情绪紧张、恐惧及行为上防备状态,同时伴有血压升高、心率加快、交感神经紧张性加强以及某些内分泌激素水平的变化.久之,升压反应逐渐发展为持续的血压升高,导致中枢心血管调节功能失常,这种环境应激因素长期作用形成的高血压称为应激性高血压[1].应激性高血压的中枢发病机制现已成为神经心血管领域一个研究热点.系列资料显示,多种神经递质和/或调质、激素等参与应激反应,在应激过程中神经内分泌、心血管等的调节机能发生相应改变.因此推测,应激性递质的改变与应激性心血管反应之间可能存在有机的联系.     

内质网应激在压力性负荷高血压大鼠血管重构中的作用

目的研究内质网应激(ERS)在压力性负荷高血压大鼠血管重构中的作用。方法 90只Wistar大鼠分为对照组、模型组。模型组采用腹主动脉狭窄术建立高血压大鼠模型,各组按术后时间1 w、2 w、4 w、6 w时采用鼠尾动脉测压法测量动物血压,随后麻醉动物分离并截取主动脉标本行病理切片和免疫组化处理,再利用图像分析系统测量血管壁肌层厚度、Western印迹检测葡萄糖调节蛋白(GRP) 78和CHOP的表达、TUNEL法检测血管平滑肌细胞凋亡率。结果模型组术后血管平滑肌细胞形态改变,血压、动脉血管壁肌层厚度和平滑肌细胞凋亡率可时间依赖性增大,GRP78在术后1、2 w表达显著升高,4、6 w表达降低,而CHOP在术后2 w以后表达才升高,且随时间推迟,这种高表达越显著。结论 ERS的双向调节作用参与高血压血管重构,压力性负荷所致的高血压发生早期,ERS保护性因子GRP78占主导地位;应激中晚期,损伤因子CHOP表达升高发挥作用,使构成血管壁的肌层细胞凋亡增多,同时血管中膜肌层增厚。     

运动训练降低血压的机制:动脉压力反射

<正>动脉压力反射是血压调节的重要机制,高血压患者普遍存在动脉压力反射功能降低[1-3]。近年研究证实,动脉压力反射功能减退不仅增加心血管事件和脑血管意外的发生率,而且提示预后不良[4-5]。运动训练是高血压非药物治疗的主要措施。运动训练不仅通过舒张血管降低高血压,还可通过增强动脉压力反射功能降低高血压,改善心血管病的预后[6]。本文就动脉压力反射与血压调节、动脉压力反射在运动训练降低     

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.