阿尔茨海默病大鼠海马胆固醇水平升高对tau蛋白磷酸化程度增加的影响

目的观察海马胆固醇含量升高后tau蛋白磷酸化程度的变化,探讨其在阿尔茨海默病(AD)中可能的作用。方法水迷宫训练大鼠7 d筛选合格大鼠后,海马直接注射不同剂量胆固醇,72 h后水迷宫检测行为学变化,并以免疫印迹和免疫组织化学方法检测大鼠海马tau蛋白磷酸化水平。结果注射胆固醇后72 h,中高剂量组大鼠水迷宫潜伏期明显延长(P<0.01),tau蛋白PHF-1位点磷酸化水平明显增高(P<0.01),tau-1明显降低(P<0.01),总tau蛋白(R134d)无明显变化。结论海马胆固醇水平升高可导致tau蛋白磷酸化程度增加,可能参与AD的形成。     

缺氧诱导因子-1α在老年性痴呆模型鼠海马中的表达

目的 观察老年性痴呆(AD)大鼠行为学、海马神经细胞凋亡率及缺氧诱导因子(HIF)-1α表达水平的变化.方法 侧脑室注射Aβ25～35构建AD大鼠模型,Morris水迷宫实验测试大鼠空间学习记忆能力,流式细胞术检测海马神经细胞凋亡率, Western印迹技术检测大鼠海马HIF-1α蛋白的表达.结果 Morris水迷宫实验结果显示AD组大鼠平均逃避潜伏期显著延长(P<0.05),流式细胞分析结果显示,AD组海马神经细胞凋亡百分率较正常对照组显著升高(P<0.05),Western印迹检测结果显示,AD组海马神经细胞HIF-1α蛋白表达水平较正常对照组显著升高(P<0.05).结论 侧脑室注射Aβ25～35成功构建AD大鼠模型并上调海马神经细胞HIF-1α水平表达.     

淀粉样蛋白诱导内质网应激的发生及二苯乙烯苷的干预影响

目的探讨在阿尔茨海默病(AD)脑损伤中,β淀粉样蛋白(Aβ)神经毒性对大鼠行为学和内质网应激分子伴侣GRP78的影响,及何首乌提取物二苯乙烯苷(TSG)的干预作用。方法选择Wistar大鼠80只,随机分为对照组、假手术组、模型组、TSG组,各20只。采用立体定向仪下于海马部位注射微量Aβ_(1 42)造模,Y电迷宫及Morris水迷宫检测行为学变化,RT-PCR及Western boh法检测制模前3 d及制模后3、21 d的海马神经元内质网分子伴侣GRP78 mRNA及蛋白的表达。结果与对照租和假手术组比较,模型组大鼠躲避电刺激次数增加,潜伏期延长,游泳路程增加及穿越平台次数减少;GRP78 mRNA及蛋白的表达一致,蛋白表达在3 d开始升高,21 d下降至正常,各时间点比较差异有统计学意义(F=182.0,P<0.05);与模型组比较,TSG组大鼠躲避所需的电刺激次数减少,潜伏期缩短,游泳路程缩短,穿越平台次数增加;GRP78表达在3 d时明显升高,差异有统计学意义(t=1 6.4317,P<0.05)。结论 Aβ可诱导内质网应激分子伴侣GRP78表达升高,启动内质网自稳调节系统;TSG可通过上调GRP78表达,抵抗Aβ的神经毒性,改善大鼠行为学表现。     

弓形虫感染对大鼠海马超微结构和抗氧化能力的影响

目的观察弓形虫感染对大鼠海马超微结构、海马组织超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量以及空间学习记忆能力的影响。方法将20只成年雄性SD大鼠随机分成2组:弓形虫感染组和健康对照组。弓形虫感染组每只大鼠腹腔注射纯化弓形虫速殖子107/ml×2 ml;健康对照组大鼠每只腹腔注射2 ml灭菌生理盐水。弓形虫感染9周后Morris水迷宫法测试各组大鼠空间学习记忆能力;应用黄嘌呤氧化酶法测定SOD活性;硫代巴比妥酸比色法测定MDA含量;透射电镜观察大鼠海马线粒体和突触结构的改变。结果 Morris水迷宫平均潜伏期弓形虫感染组大鼠(26.07±10.08)s,较对照组(13.46±5.43)s明显延长(P0.05);弓形虫感染组大鼠海马SOD活性(49.74±4.44)NUI/mgprot,较对照组(58.19±6.83)NUI/mgprot降低(P0.05);海马MDA含量感染组(4.48±0.65)nmol/mg-prot,较对照组(3.51±0.53)nmol/mgprot升高(P0.05)。透射电镜观察弓形虫感染组大鼠海马细胞线粒体稍有扩张,粗面内质网、核糖体依然可见,但稍欠丰富;核膜基本清晰,无染色质聚集;线粒体膜尚基本完整,髓鞘轻度崩解,游离核蛋白体多。结论弓形虫感染可使大鼠海马自由基清除能力下降,氧化应激反应增强。     

电针对衰老模型大鼠学习记忆及海马CA1区LTP的影响

目的 研究电针对D-半乳糖致衰老大鼠学习记忆障碍和海马CA1区突触传递长时程增强(LTP)效应的影响,探索电针改善学习和记忆的作用机制.方法 将SD大鼠随机分为正常对照组、模型组和电针组.采用腹腔注射D-半乳糖的方法建立衰老大鼠模型;电针组选取百会和足三里穴给予大鼠电针治疗,参数设定为:3 Hz,1 mA,连续波.采用Morris水迷宫观察大鼠行为学变化;并采用高频刺激Schaffer侧支,然后在同侧海马CA1区诱导LTP的方法检测大鼠海马突触可塑性的变化.结果 模型组与正常对照组相比水迷宫测试中的逃避潜伏期明显延长,距离百分比明显降低(P＜0.05,P＜0.01);而电针组与模型组相比潜伏期明显缩短,距离百分比明显增大(P＜0.01).模型组与正常对照组相比海马CA1区LTP明显受到抑制(P＜0.01),而电针组能减轻D-半乳糖对海马CA1区LTP的抑制作用,明显改善突触功能的可塑性(P＜0.05).结论 电针可改善由D-半乳糖致衰老大鼠学习记忆能力,其作用机制之一可能与大鼠海马CA1区LTP的提高有关.     

阿尔茨海默病大鼠模型学习记忆能力的改变及其机制研究

目的在体条件下观察β-淀粉样肽(beta-amyloid peptide,Aβ)所致的阿尔茨海默病(Alzheimer's disease,AD)大鼠模型的学习记忆能力及N-甲基天冬氨酸受体(N-methyl-D-aspartate receptor,NMDAR)的变化,探讨AD的发病机制.方法 Aβ1～40 μl(10 μg/μl)在立体定位仪下注入大鼠海马建立大鼠 AD模型,2 w后测水迷宫潜伏期、长时程增强(Long term potentiation,LTP)、原位杂交方法检测大鼠海马NMDAR-mRNA的表达.结果 Aβ注射2 w后水迷宫潜伏期与模型组术前及对照组术后相比显著延长(P＜0.05),模型组刺激前后局部兴奋性突触后电位(field-excitory postsynaptic potentiation,fEPSP)的斜率变化与对照组相比显著下降(P＜0.01),模型组的海马CA1、CA3区NMDAR-mRNA的表达与对照组相比显著降低(P＜0.05,P＜0.01).相关性分析表明,AD模型2 w后LTP检测的结果与NMDAR-mRNA的表达呈正相关.结论 Aβ可能通过降低NMDAR的活化状态,导致大鼠水迷宫潜伏期延长、海马LTP降低,形成AD学习记忆障碍和痴呆.     

重组人促红细胞生成素对脑创伤大鼠神经功能和空间记忆的影响

目的 研究重组人促红细胞生成素(rhEPO)对颅脑创伤大鼠行为学和神经功能恢复的影响.方法 30只成年雄性Wistar大鼠,随机分为假手术组、生理盐水对照组和rhEPO治疗组.治疗组大鼠于打击后半小时内腹腔注射rhEPO 5 000 U,连续注射5d,对照组打击后半小时内腹腔内注射等量生理盐水.于术后1、4、7、14、21、25 d对3组大鼠神经功能进行mNSS评分.术后21 ～25 d进行水迷宫实验,记录大鼠每日逃避潜伏期和目标象限百分率.结果 mNSS评分结果 显示,与生理盐水治疗组比较,rhEPO治疗组大鼠于伤后第14、21、25天其行为学功能得到明显改善(P＜0.05).rhEPO治疗组大鼠伤后24和25 d的象限百分率明显比生理盐水治疗组大鼠升高(P＜0.05),逃避潜伏期短于生理盐水治疗组(P＜0.05).结论 rhEPO对脑创伤大鼠行为学功能和学习及记忆功能的恢复有明显的促进作用.     

灵芝多糖肽对Alzheimer样大鼠海马超微结构和抗氧化能力的影响

目的 观察灵芝多糖肽(GLPP)对Alzheimer样大鼠海马超微结构、海马组织超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量以及空间学习记忆能力的影响.方法 雄性Wistar大鼠60只,随机分为对照组、模型组、NS组、GLPP组,每组15只.除对照组(正常昼夜节律)外,其余各组每天连续光照(光照度400 Lux)24 h,共30 d.其间GLPP组每天1次灌胃 GLPP(250 mg/kg);NS组灌胃相同体积的生理盐水.光照30 d后Morris水迷宫法测试各组大鼠空间学习记忆能力,黄嘌呤氧化酶法测定SOD活性,硫代巴比妥酸比色法测定MDA含量,透射电镜观察海马线粒体和突触结构的改变.结果 寻台潜伏期模型组大鼠较对照组明显延长(P＜0.05),GLPP组较模型组明显缩短(P＜0.05);NS组与模型组比较无显著差异.模型组较对照组海马SOD活性降低、MDA含量升高(P＜0.05);GLPP组较模型组SOD活性升高、MDA含量降低(P＜0.05);NS组SOD活性降低、MDA含量升高,与模型组比较无显著差异.透射电镜结果 显示:对照组、GLPP组大鼠海马线粒体神经轴突和神经突触基本正常;模型组和NS组大鼠海马线粒体膜结构破坏,线粒体肿胀,线粒体嵴模糊、消失,结构紊乱,神经髓鞘内神经细丝稀少,神经突触缺失、减少,突触密度降低,突触间隙不清,突触小泡减少.结论 GLPP可防止持续光照对大鼠海马超微结构的破坏和减轻Alzheimer样大鼠的空间记忆障碍.     

多奈哌齐对侧脑室注射链脲菌素致痴呆大鼠的治疗作用

目的研究多奈哌齐对脑室注射链脲菌素(STZ)致痴呆大鼠的治疗作用。方法健康SD雄性大鼠24只,随机分为对照组、模型组、多奈哌齐治疗组,每组8只。模型组和治疗组在手术的第1天和第3天分别向两侧侧脑室内注射STZ 3 mg/kg,对照组给予相同体积的柠檬酸缓冲液。多奈哌齐治疗组于手术前10 d给予多奈哌齐0.45 mg/(kg·d)灌胃,术后持续8周,其余2组给予等量生理盐水。术后第10天、第8周行Morris水迷宫试验,观察大鼠学习记忆能力。术后8周处死大鼠取海马送电镜观察神经元凋亡情况。结果术后10 d水迷宫测试,与对照组比较,模型组与治疗组的潜伏期延长,过平台次数下降,差异有统计学意义(P<0.01)。术后治疗8周,与模型组比较,治疗组的潜伏期缩短,过平台次数增加,差异有统计学意义(P<0.01)。电镜下观察多奈哌齐治疗组大鼠海马细胞结构细胞凋亡程度轻。结论侧脑室注射STZ制造大鼠痴呆模型稳定性高,多奈哌齐通过减轻AD模型鼠海马神经元的凋亡,从而起到改善临床症状的作用。     

血管紧张素1-7对糖尿病大鼠海马胰岛素降解酶的表达及认知功能的影响

目的观察血管紧张素1-7对糖尿病大鼠海马胰岛素降解酶的表达及认知功能的影响。方法将40只雄性SD大鼠随机分为对照组、糖尿病组、糖尿病+Ang-(1-7)组及糖尿病+Ang-(1-7)+A-779组,每组10只,腹腔注射STZ建立糖尿病大鼠模型。Morris水迷宫测试大鼠逃避潜伏期的时间和穿越目标区域的次数,RT-PCR和Western印迹检测大鼠海马胰岛素降解酶mRNA及蛋白的表达情况。结果与对照组相比,糖尿病组和糖尿病+Ang-(1-7)+A-779组逃避潜伏期时间延长(P<0.05),穿越目标区域次数减少(P<0.05),海马部位的胰岛素降解酶mRNA和蛋白的表达水平显著下降(P<0.05);与糖尿病组相比,糖尿病+Ang-(1-7)组大鼠逃避潜伏期时间和穿越目标区域次数的成绩明显改善(P<0.05),海马部位胰岛素降解酶的mRNA和蛋白表达水平明显增高(P<0.05)。结论 Ang-(1-7)对糖尿病大鼠认知功能有改善作用,其机制可能与上调了胰岛素降解酶的mRNA和蛋白表达水平有关。     

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.