血管内皮生长因子在脑缺血中的保护机制

血管内皮生长因子（VEGF）是作用最强的血管生成因子之一。研究证明,在脑缺血动物脑内注入外源性VEGF能促进血管生成,但同时在缺血半暗带内会发生“盗血”现象。另一方面,VEGF对中枢神经系统具有神经发生、直接神经营养和神经保护等多重保护作用。从分子水平了解这些神经保护机制,更有益于临床开发治疗脑缺血的措施。     

红细胞生成素对脑缺血损伤的保护作用

研究表明,红细胞生成素(EPO)对脑缺血具有神经保护作用,且外源性EPO也可通过血脑屏障对缺血性脑损伤发挥神经保护作用。其机制可能包括上调细胞凋亡抑制基因bcl-2、bcl-xl表达、抑制凋亡过程中关键蛋白酶的表达、抑制NO过度合成、抗谷氨酸兴奋毒性等。     

缺血性脑损伤诱导的神经发生及其调节机制

传统观点认为,中枢神经系统神经元缺乏再生能力.最近的研究发现,脑缺血可激活成年哺乳动物脑内的神经发生,为脑缺血损伤后的神经修复带来了新的希望.充分了解成年神经发生的部位、过程,缺血后神经发生及其调控机制很有必要.     

脑缺血后神经营养因子的表达及神经保护机制

已有证据表明 ,脑缺血后多种神经营养因子及其受体表达上调 ,并对缺血性损伤起保护作用。脑缺血诱导神经营养因子表达上调的主要因素为谷氨酸释放、兴奋性氨基酸受体激活、钙离子内流以及细胞膜去极化。神经营养因子对脑缺血的神经保护机制包括 :(1)拮抗兴奋性氨基酸毒性 ,维持细胞内钙离子稳定 ;(2 )增强抗氧化酶活性 ,抑制诱导型一氧化氮合酶的表达 ,抗自由基损伤 ;(3)抗细胞凋亡 ;(4 )增强蛋白激酶C活性 ;(5 )修复受损神经元。研究脑缺血神经营养因子的表达及神经保护机制 ,有助于进一步阐明脑缺血神经损伤的病理生理机制。     

脑缺血后神经营养因子的表达及神经保护机制

已有证据表明,脑缺血后多种神经营养因子及其受体表达上调,并对缺血性损伤起保护作用。脑缺血诱导神经营养因子表达上调的主要因素为谷氨酸释放,兴奋性氨基酸受体激活、钙离子内流以及细胞膜去极化。神经营养因子对脑缺血的神经保护机制包括;（1）拮抗兴雷达性氨基酸毒性,维持细胞内钙离子稳定;（2）增强抗氧化酶活性,抑制诱导型一氧化氮合酶的表达,抗自由基损伤;（3）抗细胞凋亡;（4）增强蛋白激酶C活性;（5）修复受损神经元。研究脑缺血神经营养因子的表达及神经保护机制。有助于进一步阐明脑缺血神经损伤的病理生理机制。     

拉莫三嗪对脑缺血的神经保护作用

研究表明,拉莫三嗪对脑缺血具有神经保护作用,其机制较为复杂,涉及多个方面,如对离子通道、氨基酸神经递质、自由基和脂质过氧化的作用等。文章就近年来拉莫三嗪对脑缺血的神经保护作用及其机制的研究进展做了综述。     

拉莫三嗪对脑缺血的神经保护作用

研究表明，拉莫三嗪对脑缺血具有神经保护作用，其机制较为复杂，涉及多个方面，如对离子通道、氨基酸神经递质、自由基和脂质过氧化的作用等。文章就近年来拉莫三嗪对脑缺血的神经保护作用及其机制的研究进展做了综述。     

脑缺血与内源性神经保护

脑缺血后一系列损伤级联反应既可启动缺血性脑损伤的诸多环节 ,又可启动内源性神经保护机制 ,增强内源性神经保护效应对限制缺血损伤和促进可逆性受损的神经组织的修复和再生至关重要。文章就近年来内源性神经保护的机制和内源性神经保护增效剂方面的研究作了综述。     

内源性神经干细胞与缺血性脑损伤

应用神经干细胞治疗缺血性脑损伤包括内源性神经干细胞策略和外源性神经干细胞移植策略两种,鉴于内源性神经干细胞较之于外源性神经干细胞具有许多明显的优势,目前国外对前者的研究日趋活跃。文章介绍了脑缺血时内源性神经干细胞的生成、增殖、迁移和分化及将其应用于临床治疗的可行性。     

白藜芦醇在脑缺血中的神经保护作用

白藜芦醇是存在于多种植物内的一种多酚化合物,具有抗氧化、抗炎、抑制凋亡和清除自由基等作用.白藜芦醇预适应通过激活沉默信息调节因子2同源体1对缺血再灌注大鼠起着神经保护作用,这种作用类似于脑缺血预适应.此外,白藜芦醇还可通过抑制氧自由基和炎性细胞因子生成,缩小脑缺血再灌注小鼠梗死体积和改善神经功能.文章综述了白藜芦醇在脑缺血中的神经保护作用及其机制.     

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.