醛固酮对急性心肌梗死后左心室重构影响的研究进展

心力衰竭已经成为影响人们生命和生活质量的主要疾病,心肌梗死后心室重构是其重要原因之一,急性心肌梗死后神经内分泌系统的过度激活对心室重构的影响已成为共识。作为肾素-血管紧张素-醛固酮系统的重要组成部分,醛固酮对于心血管系统的病理生理作用以及醛固酮逃逸现象确定了醛固酮受体拮抗剂在心力衰竭治疗中的决定性地位。现就醛固酮对于急性心肌梗死后左心室重构影响的研究进展作一综述。     

醛固酮及其拮抗剂在心力衰竭中的研究进展

本文介绍了醛固酮新近发现的一些重要作用引起心肌纤维化，心肌重构，心律失常，血管的改变；心力衰竭中醛固酮逃逸现象以及醛固酮拮抗剂安体舒通的应用进展。     

醛固酮及其拮抗剂在心力衰竭中的研究进展

本文介绍了醛固酮新近发现的一些重要作用；引起心肌纤维化，心肌重构，心律失常，血管的改变；心力衰竭中醛固酮逃逸现象以及醛固酮拮抗剂安体舒通的应用进展。     

醛固酮拮抗剂治疗心血管疾病的研究进展

醛固酮的经典作用是与肾脏远曲小管和集合管细胞中醛固酮受体结合,引起保钠排钾和水钠潴留.近年研究发现,醛固酮受体广泛分布于心肌细胞、血管平滑肌细胞、成纤维细胞.在心力衰竭、高血压、急性心肌梗死(AMI)等病理条件下,血浆或心血管局部组织中醛固酮水平可明显升高,过多的醛固酮通过其受体可引起心肌纤维化、血管顺应性下降、内皮功能失调、儿茶酚胺释放、心律失常等有害作用.可见醛固酮是导致心血管损害的重要的神经内分泌因素,而醛固酮拮抗剂如:螺内酯、依普利酮(eplerenone)、坎利酮(canrenone)、坎利酸(canrenate)可逆转上述不利作用,在心力衰竭、高血压、AMI患者的治疗中有望发挥重要作用[1].     

安体舒通对继发于特发性扩张型心肌病或缺血性心肌病充血性心力衰竭室性心律失常的作用

醛固酮通过细胞内和膜受体作用,促发电解质失衡和水潴留,影响心肌电生理,并致心肌纤维化,诱发泵功能不全和心律失常,对充血性心衰病人的室性心律失常起重要作用。该研究的目的是调查醛固酮拮抗剂安体舒通对充血性心衰人群室性心律失常发生频率的影响。     

安体舒通治疗慢性充血性心力衰竭12例疗效观察

安体舒通的结构式类似醛固酮，因而对后者起竞争性拮抗作用，减少醛固酮在远曲小管钠—钾交换作用，属于弱利尿剂。近年来，我们在临床实践中对一些常规利尿作用欠佳的慢性心衰患者给予安体舒通口服，可明显改善心衰病人的症状和体征。现将临床观察结果报道如下：     

醛固酮受体阻滞剂在急性心肌梗塞中的应用及其机制

急性心肌梗塞（AMI）的病人并发心力衰竭（CHF）的发生率约为32％～48％，心律失常的发生率为75％～95％。因此对心衰与心律失常的控制成为AMI治疗中的重要组成部分。近年来对醛固酮受体阻滞剂螺内酯（又称安体舒通）的研究逐渐深入，它的抗心衰与抗心律失常的作用，使其在AMI的治疗中的地位与日俱增。     

醛固酮拮抗剂螺内酯在慢性心力衰竭治疗中的作用机制和应用进展

近年来对慢性心力衰竭 (心衰 )机制的研究逐渐深入 ,慢性心衰的发生、发展是一个非常复杂的过程 ,有多种因素参与。近年大量的研究显示 ,在心衰的发生、发展过程中 ,神经、激素系统长期过度增强是慢性心衰进行性恶化的一个重要原因。调整交感神经系统和肾素 血管紧张素 醛固酮系统 (ＲＡＡｓ )是心衰治疗的关键。醛固酮拮抗剂螺内酯 (又称安体舒通 ,ｓｐｉｒｏｎｏｌａｃｔｏｎｅ ,ａｌｄａｃｔｏｎｅ)是继血管紧张素转换酶抑制剂 (ＡＣＥＩ)和 β受体阻滞剂后第三个能降低心衰患者死亡率的药物[1 ] 。本文就醛固酮对心衰的影响 ,及螺内酯…     

醛固酮在心血管疾病中的作用研究

传统认为醛固酮由肾上腺皮质球状带细胞分泌并参与水盐代谢,现发现肾上腺外组织(血管、心脏和脑组织)也可分泌醛固酮并同时存在盐皮质激素受体。在心血管系统醛固酮参与氧化应激,诱导心肌纤维化从而参与心肌重构,醛固酮也影响心肌离子流和心肌复极从而与异位电活动有关。盐皮质激素受体阻断刺可明显改善严重心衰和急性心肌梗死后左室功能障碍病人的预后且对原发性高血压病人有靶器官保护作用。     

醛固酮在心血管疾病中的作用研究

传统认为醛固酮由肾上腺皮质球状带细胞分泌并参与水盐代谢,现发现肾上腺外组织(血管、心脏和脑组织)也可分泌醛固酮并同时存在盐皮质激素受体.在心血管系统醛固酮参与氧化应激,诱导心肌纤维化从而参与心肌重构,醛固酮也影响心肌离子流和心肌复极从而与异位电活动有关.盐皮质激素受体阻断剂可明显改善严重心衰和急性心肌梗死后左室功能障碍病人的预后且对原发性高血压病人有靶器官保护作用.     

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.     

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.     

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.     

Variabilité des concentrations plasmatiques de l’angiotensinogène et risque d’hypertension artérielle chez le rat transgénique

Aim

Genetic polymorphisms of the human angiotensinogen gene are frequent and may induce up to 30% increase of plasma angiotensinogen concentrations with a blood pressure increase of up to 5 mmHg. Their role for the pathogenesis of human arterial hypertension remains unclear. High plasma angiotensinogen levels could increase the sensitivity to other blood pressure stressors.

Methods

Male transgenic rats with a 9-fold increase of plasma angiotensinogen concentrations and male non-transgenic rats aged 10 weeks were treated or not with NG-Nitro-L-arginine-methyl ester for 3 weeks in their drinking water (n = 3/group). Systolic blood pressure and body weight were measured at baseline and at the end of the study when left ventricular weight and ventricular expression of angiotensin I-converting enzyme and procollagen Iα1 were determined (polymerase chain reaction).

Results

At baseline, transgenic rats had +18 mmHg higher bood pressure and –8% lower body weight compared to non-transgenic rats (P < 0.05) without significant changes for the vehicle groups throughout the study (P > 0.05). NG-Nitro-L-arginine-methyl ester increased blood pressure, left ventricular weight and left ventricular weight indexed for body weight by +41%, +17.6% and +18.6% (P < 0.05) in transgenic and +25%, +5.3% and +6.7% (P > 0.05) in non-transgenic rats compared to untreated animals, respectively. Cardiac gene expression showed no differences between groups (P > 0.05).

Conclusion

Increased plasma angiotensinogen levels may sensitize to additional blood pressure stressors. Our preliminary results point towards an independent role of angiotensinogen in the pathogenesis of human hypertension and associated end-organ damage.