实验性肠阿米巴病及病理变化

有关实验性肠阿米巴病及病理学研究的文献较多,经实验证明,豚鼠及大鼠盲肠接种阿米巴后,感染率高,易发生肠壁溃疡,常用作复制本病的动物模型。目前已知实验动物的易感性与遗传、年龄、体重、营养状况及免疫状态等因素有关,并受到实验动物体内已感染的种属阿米巴的影响。不同的培养方法可影响接种虫株的毒力,以对数生长期的滋养体毒力最强;通常应用经胃肠道灌注或盲肠内接种等方法造成实验动物的感染。动物模型的肠壁病变与人类急性期的病变相同,好发于回盲肠交界处,肉眼可见肠壁出现灶状充血、出血、渗出及粘连和大小不等的溃疡;光镜观察可根据肠壁的非特异性炎症以及溃疡累及的深度,进行病变的分级计分。现有的电镜观察已发现是阿米巴主动地粘附于宿主细胞表面,通过释放毒素及酶的作用,导致宿主细胞变性坏死脱落。阿米巴再由伪足的机械性运动侵入组织中,应用扫描电镜观察还可了解病变的范围及立体结构的改变。目前已有少数学者应用抗阿米巴抗体进行了部分免疫病理学的研究,证实了抗阿米巴抗体与组织中的阿米巴特异性结合后显色,可较常用的HE及PAS染色法等查见更多的滋养体,明显地提高了检出率。应用动物模型进行本病的病理学研究有助于进一步了解阿米巴的入侵部位、方式及致病机理,为防治本病提供形态学依据。     

溶组织内阿米巴与日本血吸虫并存感染实验观察

选用长爪沙鼠,分别经皮肤感染20条日本血吸虫尾蚴和盲肠内接种溶组织内阿米巴滋养体5×10~5个/0.5ml,建立溶组织内阿米巴与日本血吸虫并存感染的实验动物模型。结果表明,血吸虫感染可以促进肠阿米巴病的发生与发展,并使潜在的溶组织内阿米巴感染发展成侵入型肠阿米巴病。并存感染既有阿米巴感染和血吸虫感染的部分病理学特征,又有本身独特的病理学变化,机体的应激反应参与致病过程。病灶区经常可见滋养体与虫卵的粘附,两者之间似存在亲和性。     

以无菌或单菌培养的溶组织内阿米巴作肠侵袭性阿米巴病的啮齿动物实验模型

本文作者报道了一种简单可靠的肠侵袭性阿米巴病的豚鼠和仓鼠的动物模型。选用溶组织内阿米巴强毒株HM1:IMSS在36℃BI-S-33培养基中无菌或单菌(Clostridium symbiosium)培养。动物选用小猫(445～775g)、豚鼠(150～350g)和仓鼠(130～170g)。动物分两组。第一组采用标准接种法,即在麻醉下通过手术将滋养体直接接种于盲肠或结肠。第二组采用“灌洗封闭盲肠接种法”,即将盲肠从腹中取出后,将一注射针头靠近结盲瓣处穿入肠腔,用丝线固定。在结扎回肠远端后,沿盲肠近侧部切下,在切口     

抗霉药物对实验肠阿米巴病的作用

作者用属于多烯抗菌素的levorin及制霉菌素,分别对肠阿米巴病的治疗效果进行了实验研究。将自急性阿米巴痢疾患者分离出的溶组织内阿米巴株,接种于大白鼠的盲肠中,每鼠     

溶组织内阿米巴5例的粪便鉴定

目的探讨溶组织内阿米巴的粪便鉴定,并就溶组织内阿米巴包囊及滋养体的镜检要点及常见漏检原因进行讨论。方法用显微镜法对5例外院漏诊的肠阿米巴病患者粪便标本进行检验,分别用生理盐水涂片法、碘染色和苏木素染色法,在显微镜下进行观察鉴定。结果溶组织内阿米巴包囊及滋养体在生理盐水涂片、碘染色涂片和苏木素染色涂片中有典型的形态学特点。结论对于可疑肠阿米巴病患者,应多次及时送标本进行检验,采用几种不同方法进行鉴定,并注意将溶组织内阿米巴与吞噬细胞及迪斯帕内阿米巴相鉴别。     

胸腔阿米巴病的诊治(附14例报告)

阿米巴病为一常见的肠道传染病。阿米巴滋养体可侵犯人体多处脏器,除常见的阿米巴肝、肠病外,胸腔(包括肺、胸膜及心包)阿米巴病亦时有所见。胸腔阿米巴病病情复杂,误诊率甚高,尤应引起重视。我院1963～1983年收治胸腔阿米巴病18例(不包     

用酶联免疫吸附试验检测粪便中溶组织内阿米巴抗原

肠阿米巴病的确诊,有赖于粪便镜检找到溶组织内阿米巴包囊或滋养体。但此法耗     

双抗体夹心ELISA检测人粪中的溶组织内阿米巴抗原

肠阿米巴病的诊断有赖于粪检发现溶组织内阿米巴滋养体或包囊,但当大量形态上与其相似的非致病性阿米巴类和其它肠原虫存在时,极易误诊。本文报道了用双抗体夹心ELISA检测粪内溶组织内阿米巴滋养体的可溶性抗原,并对其敏感性、特异性及临床应用价值等加以讨论。用培养的溶组织内阿米巴HK 9株制备抗原,并免疫家兔,以饱和硫酸铵分步沉淀得     

田鼠的肝损害对发生阿米巴肝脓肿的作用

实验的方法是将正常金色田鼠分为两大组,用乙醚麻醉后,行纵切术切开腹部的皮层、腹壁及腹膜,切口长约1～2厘米。两大组的实验方法,第1大组3个小组从盲肠静脉注入的溶组织内阿米巴滋养体数为100,000个,第2大组3个小组的阿米巴滋养体接种数为200,000个。接种的培养物均为不含细菌和短膜虫的溶组织内阿米巴滋养体,注射量均为0.15毫升。两个大组的甲组仅接种     

影响溶组织内阿米巴致病力的生物因素

溶组织内阿米巴的致病作用受多种因素影响。生物因素通过对阿米巴毒力、致病性以及宿主的机能状态、免疫调节等方面的作用,影响阿米巴病的发生与发展。无菌培养的阿米巴在仓鼠肝内不产生肝脓肿,在豚鼠盲肠内也不发生侵袭性病变,阿米巴只有和细菌相互作用后,才有明显的致病性和使宿主发生肝脓肿的能力。细菌可提供适宜的理化、营养条件和附加体样致病因子,以及在消除毒性分子、加强酶的功能、促进与阿米巴的粘附等方面起作用。迄今已在阿米巴内区分出三种病毒。病毒在核内大量复制,形成微丝,导致核溶解、阿米巴死亡。病毒基因还可整合到阿米巴的DNA上。阿米巴似可作为甲肝病毒的传播媒介。艾滋病患者合并的阿米巴病病变往往更为严重。霉菌寄生于阿米巴内,显示对核的破坏作用;阿米巴病合并念珠菌和放线菌感染时,病变加剧。和弓形体一起培养的阿米巴,对肠上皮细胞损害力增强。感染了血吸虫、粪类圆线虫、鞭虫等的患者,肠道常发生急性炎症反应,致使肠上皮细胞变性、渗出、坏死,局部抗溶组织内阿米巴感染的能力降低,促进阿米巴的入侵。另外,蠕虫感染后,宿主全身免疫功能减退,白蛋白下降、贫血以及巨噬细胞活力受抑,也有利于阿米巴病的发生与发展。     

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.