肺血管内皮细胞功能障碍与肺动脉高压

肺动脉高压的发病机制是一个复杂的、多因素参与的过程.近年来,逐步形成内皮功能紊乱学说,认为肺血管内皮是引起血管收缩和特征性病理改变的首要因素.本文就肺血管内皮细胞功能障碍和肺动脉高压的研究进展作一综述.     

内皮祖细胞和肺动脉高压

肺动脉高压是以肺动脉压和肺血管阻力进行性增加及右心功能衰竭为特征,内皮功能障碍为主的恶性肺血管疾病.本文总结了近年来内皮祖细胞(EPC)动员、归巢分子生物学的研究进展.研究了血管内皮生长因子等生长因子和他汀类等药物对EPC动员,归巢治疗肺动脉高压的影响以及EPC、基因修饰后EPC移植对肺动脉高压治疗的影响.同时讨论了EPC治疗的潜在不良反应.EPC为肺动脉高压患者提供新的治疗方法.     

慢性阻塞性肺疾病相关性肺动脉高压研究进展

肺动脉高压是慢性阻塞性肺疾病的一个重要合并症.慢性阻塞性肺疾病相关的肺动脉高压多为轻到中度且进展缓慢,香烟烟雾、炎症产物引起内皮损害,造成内皮功能失调;慢性低氧引起肺血管收缩;肺血管重塑导致管腔变小;血管膨胀性降低,阻力增加;重度肺气肿时肺-毛细血管的丧失等均与慢性阻塞性肺疾病时的肺动脉高压相关.     

内皮祖细胞在肺动脉高压的作用

内皮祖细胞是成熟血管内皮细胞的前体细胞,属于干细胞群体,其在血管再生与修复方面的应用越来越受到关注.肺动脉高压作为一种致死性很高的肺血管疾病,其发病与血管内皮损伤密切相关.目前的研究证实,内皮祖细胞在肺动脉高压血管内皮修复中具有重要作用,内皮祖细胞移植有可能成为临床治疗肺动脉高压的一种有效手段.     

血管内皮生长因子与肺部疾病的关系

血管内皮生长因子是作用于血管内皮细胞的重要血管调节因子,它通过与内皮上的特异受体结合,发挥促进内皮细胞增殖、分化、诱导血管生成、增加微血管通透性等多种功能。近年研究显示血管内皮生长因子在慢性阻塞性肺疾病、肺动脉高压、急性肺损伤、肺癌等疾病发病中起到了重要作用。本文就血管内皮生长因子在慢性阻塞性肺疾病、肺动脉高压、急性肺损伤、肺癌等疾病中的作用综述如下。     

内皮细胞凋亡与肺动脉高压

随着肺动脉高压研究的不断深入,肺血管内皮细胞凋亡在肺动脉高压形成过程中的重要作用被逐步认识。多种疾病和环境因素导致肺血管内皮损伤、内皮细胞凋亡增加、功能障碍,从而促进肺动脉平滑肌细胞和成纤维细胞增殖、肺动脉重构和血栓形成;肺血管内皮细胞凋亡还诱导产生凋亡抵抗表型的内皮细胞过度增殖,形成丛样病变和肺血管闭塞,最终导致严重肺动脉高压。因而在肺动脉高压发生发展的不同时期,调控肺血管内皮细胞凋亡可能是预防和治疗肺动脉高压的一种新策略。     

用伊洛前列素吸入治疗心脏病患者围术期肺动脉高压

目前肺动脉高压的治疗仍然是一个棘手的问题,前列环素类似物伊洛前列素是近年来应用较多的肺动脉高压治疗药物,由于其具有高度肺血管选择性、能调节肺血管内皮功能、抑制血管重塑和微血栓形成等药物学特点,因此可明显改善血流动力学和临床症状。本文主要综述吸入伊洛前列素在成人心脏手术围术期肺动脉高压的应用。     

血管内皮功能障碍与肺动脉高压

肺动脉高压是以血管增殖重塑、原位血栓形成、肺血管床进行性闭塞、肺血管阻力进行性增高为特征的肺小动脉疾病。其发病机制是一个复杂的、多因素参与的过程。近来越来越多的研究表明,肺脏血管内皮功能障碍在肺动脉高压形成的起始及发展阶段都起着重要作用。正常的肺脏血管内皮衬于肺血管内腔表面,介于循环血和肺血管平滑肌之间。其不仅具有生理屏障功能,还有调解血管张力,血液流动性和黏附性,参与血管内皮损伤的修复,同时血管内皮可以通过膜受体感知血流动力学和血源性信号变化参与细胞间的信号传导[1]。肺脏内皮功能障碍是肺脏内皮细胞在…     

肺动脉高压神经调控机制研究进展

肺动脉高压是一种以肺血管阻力增加、肺血管系统的不良性重塑为特征, 导致右心肥厚并最终因右心衰而死亡的进行性疾病。其准确发病机制尚未完全明确, 在众多机制中, 自主神经功能紊乱也是促成肺动脉高压的因素之一。在肺动脉高压中, 交感神经过度激活是公认的一种假说, 肺动脉去神经术治疗肺动脉高压取得了一定的疗效。本文对肺血管的神经解剖基础、神经调控参与的肺动脉高压发生发展的可能机制及神经调控在肺动脉高压治疗中的应用进行系统性综述。     

循环内皮祖细胞在肺动脉高压形成中的作用及治疗学应用前景

近年来,内皮祖细胞在肺动脉高压(pulmonary arterial hypertension,PAH)形成中的作用越来越受到学术界重视,基于内皮祖细胞移植治疗PAH的报道也逐年增多.内皮祖细胞存在于骨髓、大动脉血管外膜或循环血液中,在肺动脉内皮损伤的情况下可在损伤部位增殖分化为成熟的内皮细胞,进而通过重建正常的肺血管内皮结构和功能达到治疗PAH的效果.本文对循环内皮祖细胞在PAH形成中的作用及其应用前景作一综述.     

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.     

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.     

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.     

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.