天然免疫、Toll样受体与1型糖尿病

天然免疫在识别病原微生物后可迅速被激活,在免疫系统中起着非常重要的作用。天然免疫细胞通过表达不同的模式识别受体（PRRs）来识别病原体的信号分子。这些信号分子是天然免疫的重要组成部分,统称为病原相关分子模式（PAMPs）。至今已发现的PRRs包括Toll样受体（TLRs）、视黄酸诱导基因1（RIG-1）样受体（RLRs）和NOD样受体（NLRs）。     

Toll样受体4与肝损伤

Toll样受体是近几年发现的天然免疫受体,主要参与病原微生物产物的识别及炎症信号传导,是天然免疫与获得性免疫的连接点。Toll样受体4介导内毒素引起的感染性免疫反应,参与了肝脏内的损伤、纤维化、再生与修复等炎症反应过程。     

Toll样受体与支气管哮喘

Toll样受体(Toll-like receptors,TLR)是近年发现的一组天然受体,其不仅依赖胚系基因编码的保守序列识别病原微生物和激活天然免疫,而且调节获得性免疫和诱导免疫耐受,与支气管哮喘密切相关.其宿主通过TLR识别大量病原体相关结构,利用细胞信号转导途径激活机体免疫细胞,一方面参与早期的宿主防御,在天然免疫应答中发挥重要作用;另一方面通过分泌细胞因子、趋化因子、黏附分子等参与炎症反应,最终激活获得性免疫系统.本文就近年来有关TLR的结构功能、信号通路及TLR与支气管哮喘关系作一综述.     

Toll样受体4与肝损伤

Toll样受体是近几年发现的天然免疫受体，主要参与病原微生物产物的识别及炎症信号传导，是天然免疫与获得性免疫的连接点。Toll样受体4介导内毒素引起的感染性免疫反应，参与了肝脏内的损伤、纤维化、再生与修复等炎症反应过程。     

CpG ODNs抗感染免疫作用研究进展

哺乳动物的免疫系统依赖于天然免疫和获得性免疫防御病原微生物的入侵.天然免疫是机体的第一道防线,它在病原微生物入侵时首先被激活,表达于细菌、病毒、真菌的病原相关分子模式 (pathogen-associated molecular patterns,PAMPs)被模式识别受体 (pattern recognition receptor,PRR)识别.不同微生物感染所表达的PAMPs可激活天然免疫系统,这些被激活的天然免疫应答在体内可控制感染有机物的增殖和传播,随后宿主对病原体特异性表达产生相对应的获得性免疫应答,为机体提供长期的保护作用.     

Toll样受体与炎症性肠病

Toll样受体(TLRs)是天然免疫系统中的细胞跨膜受体,可识别病原相关分子模式(PAMP).不同的PAMP激活不同的TLR,TLR在髓样分化蛋白(MD2)、CD14辅助下,通过MyD88依赖型信号通路或非MyD88依赖型信号通路激活核因子-κB(NF-κB)、干扰素调节因子3/7(IRF3/7)及活化蛋白-1(AP-1),最终诱导下游目的基因表达.TLR对肠黏膜天然免疫反应调节发挥关键作用;而病原微生物在IBD的发生中起重要作用.生理情况下,肠上皮细胞持续表达TLR3和TLR5,而TLR2和TLR4几乎无法检测到;但在IBD患者的肠上皮细胞表面,却可检测到TLR2和TLR4的表达.随着对TLR信号通路研究和认识的不断深入,以TLR为靶点的药物研究也正成为一个热点.     

Toll样受体与信号转导

Toll样受体是一组Ⅰ型跨膜受体 ,通过识别入侵病原微生物的配体 ,激发天然免疫应答 ,启动促炎症细胞因子和共刺激分子的表达。Toll样受体在信号转导中发挥重要作用 ,MyD88是信号转导通路中的关键蛋白。通过对Toll样受体的研究有助于进一步认识宿主的免疫反应。     

尘螨过敏原调控气道上皮细胞相关致敏机制研究进展

尘螨是最常见的吸入性过敏原之一,是引起过敏性哮喘、过敏性鼻炎、特应性皮炎等过敏性疾病的重要因素。尘螨过敏已被世界卫生组织(WHO)视为全球性卫生问题之一,但迄今尚无尘螨诱发的过敏性疾病的有效治疗方案。作为气道抵抗过敏原、病毒、细菌、环境污染物等炎症刺激和抗原的第一道防线,气道上皮细胞构筑了肺组织与外环境间的第一道屏障,在多种急慢性肺部炎症性疾病发病机制中发挥了关键作用。尘螨过敏原刺激后,气道上皮细胞参与过敏原致敏及气道炎症反应过程,在呼吸系统天然免疫功能中发挥重要作用。本文主要就尘螨过敏原及其调控气道上皮细胞炎症反应致过敏机制研究进展作一综述。     

Toll样受体与信号转导

Toll样受体是一组I型跨膜受体，通过识别入侵病原微生物的配体，激发天然免疫应答，启动促炎症细胞因子和共刺激分子的表达。Toll样受体在信号转导中发挥重要作用，MyD88是信号转导通路中的关键蛋白。通过对Toll样受体的研究有助于进一步认识宿主的免疫反应。     

支气管哮喘与Toll-样受体的关系研究进展

支气管哮喘(简称哮喘)是由多种细胞(如嗜酸粒细胞、肥大细胞、淋巴细胞、中性粒细胞、气道上皮细胞等)和细胞组分参与的气道慢性炎症性疾病,是遗传易感个体与各种环境因素共同作用的结果.研究发现,Toll-样受体(TLR)和免疫细胞在哮喘的发生发展中起着重要作用.TLR通过识别多种病原体,激活Th1或Th2等免疫反应,被认为是防止或促进哮喘发生一个的重要因素.本文对TLR及其相关配体在哮喘发病机制中的作用作以下综述,为哮喘的治疗提供新思路.     

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.