蠕虫感染与过敏性和自身免疫性疾病

许多研究发现蠕虫感染后虫源性分子诱导免疫细胞形成免疫调节网络,介导免疫抑制,从而抑制过敏性和自身免疫性疾病。寄生虫可以通过诱导免疫调节细胞活化和产生细胞因子发挥抑制效应,从而影响其他免疫相关疾病。然而,蠕虫感染与免疫相关疾病之间的调节机制尚无明确的结论。一些蠕虫感染可以保护和控制过敏性疾病,而另一些蠕虫却加剧疾病的免疫病理损害。     

蠕虫诱导的细胞因子应答的调节和生物学功能

蠕虫感染的免疫效应,即嗜酸粒细胞增多、肥大细胞增多和IgE合成增加,系由CD4~+T细胞T_H2亚群细胞的细胞因子诱导产生的:IL-4刺激IgE产生,IL-5刺激嗜酸粒细胞增多,IL-3和IL-4刺激肥大细胞增多。蠕虫感染时嗜酸粒细胞、肥大细胞及IgE增加的功能尚不明。在某些蠕虫感染时,T_H2细胞的细胞因子可能有利于宿主的保护力,而在另一些蠕虫感染时,T_H2细胞的细胞因子可能助长寄生虫的生存。     

树突状细胞在寄生虫感染中的作用

树突状细胞是一类重要的抗原提呈细胞 ,在宿主针对寄生虫感染的免疫应答过程中起到了重要作用。该文通过分析血吸虫、疟原虫、利什曼原虫、弓形虫、锥虫、丝虫等寄生虫感染的研究现状 ,对树突状细胞在诱导机体保护性免疫以及参与形成寄生虫免疫逃避中的作用机制作进一步介绍     

炎性树突状细胞的功能特性及在支气管哮喘发病机制中的作用

树突状细胞是功能最强的专职抗原递呈细胞,作为机体免疫应答的启动者在免疫应答中占有重要地位.研究显示在感染或炎症状态下由炎性单核细胞分化而来的一种树突状细胞亚型——炎性树突状细胞,参与调节免疫应答.近来,炎性树突状细胞在支气管哮喘发生机制中的作用备受关注,现就炎性树突状细胞在不同类型免疫应答的作用及其与支气管哮喘的关系作一综述.     

树突状细胞在寄生虫感染中的作用

树突状细胞是一类重要的抗原提呈细胞，在宿主针对寄生虫感染的免疫应答过程中起到了重要作用。该文通过分析血吸虫、疟原虫、利什曼原虫、弓形虫、锥虫、丝虫等寄生虫感染的研究现状，对树突状细胞在诱导机体保护性免疫以及参与形成寄生虫免疫逃避中的作用机制作进一步介绍。     

寄生虫感染对树突状细胞亚群的影响

树突状细胞(dendritic cell,DC)是目前已知功能最强的抗原提呈细胞,在宿主针对寄生虫感染的免疫应答过程中起到了重要作用。 近年来DC越来越受到的关注,寄生虫感染作用于树突状细胞亚群的研究也不断深入。本文就寄生虫感染对树突状细胞亚群的影响予以综述。     

树突状细胞与支气管哮喘研究进展

树突状细胞是目前发现的功能最强的抗原提呈细胞,其最大的特点是能显著地刺激初始型T细胞增殖。在一定条件下,树突状细胞能诱导T_(H1)/T_(H2)型应答的偏移。变应性哮喘最重要的免疫异常是T_(H1)/T_(H2)细胞比例和功能的失衡,主要表现为T_(H2)细胞的数量增多和功能亢进。因此,树突状细胞为始动气道变态反应所必需,在哮喘的发病中具有重要作用,也必将使人们对哮喘的防治产生新的认识。     

蠕虫及虫源性分子对自身免疫性疾病的保护作用

机体接触包括蠕虫在内的病源微生物机会减少,尤其在幼年时期免疫系统失去病源微生物的塑造和协调,是导致西方发达国家自身免疫性疾病和过敏性疾病发病率迅速增高的主要原因之一。蠕虫感染能激发强烈的Th2 免疫应答,可以改善Th1 介导的自身免疫性疾病的临床症状和病理过程。日益增多的流行病学及实验研究证实了蠕虫对自身免疫性疾病及过敏性疾病的保护作用,显示了优异的临床应用价值。蠕虫感染能激发强烈的Th2 免疫应答,可以改善Th1 介导的自身免疫性疾病的临床症状和病理过程。目前,蠕虫感染诱导的宿主Th2 免疫偏移已成为感染免疫调节研究的重要模型,并显示了优异的临床应用价值,具有诱人的临床应用前景。然而其负向免疫调控的机制至今尚未明了。本文回顾近年来蠕虫及其分子调节自身免疫性疾病的国内外研究进展,着重探讨蠕虫感染及其分子发挥免疫抑制作用的可能机制。     

肠道树突状细胞的特性及功能研究

树突状细胞(DC)是目前所知机体内功能最强的专职性抗原递呈细胞．在肠道内,树突状细胞不但能对致病菌产生免疫应答,而且能对肠腔内共生菌及各类食物蛋白产生免疫耐受．因此,了解DC的功能及相关作用机制对研究肠道免疫屏障具有重要意义．现就肠道树突状细胞在免疫、耐受及疾病发生过程中的作用作一综述,旨在为研究肠道屏障功能提供有益的帮助．     

宿主树突状细胞与血吸虫感染

树突状细胞是目前已知的功能最强的一类抗原呈递细胞,是连接固有免疫和获得性免疫的桥梁,近年来研究进展显著。在血吸虫病领域的研究发现,宿主树突状细胞经血吸虫感染刺激后的表型与常规成熟的表型不同。研究血吸虫感染与宿主树突状细胞之间的相互作用将有助于丰富该类细胞的生物学研究,也将为血吸虫病的疫苗和治疗研究提供支撑。     

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.     

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.     

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.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.