洛伐他汀对同型半胱氨酸硫内酯所致大鼠离体胸主动脉内皮损伤的保护作用

目的观察洛伐他汀对同型半胱氨酸硫内酯所致大鼠离体胸主动脉内皮损伤的保护作用并探讨其相关机制。方法用同型半胱氨酸硫内酯与大鼠离体胸主动脉血管环共孵育90min诱导血管内皮损伤,检测血管内皮依赖性、非内皮依赖性舒张反应以及血管组织生物化学指标,观察洛伐他汀对同型半胱氨酸硫内酯诱导的血管内皮功能损伤的影响。结果血管环与同型半胱氨酸硫内酯孵育90min后,乙酰胆碱诱导的内皮依赖性舒张反应明显降低,而硝普钠引起的非内皮依赖性舒张反应无明显改变;血管组织中丙二醛浓度显著增加,超氧化物歧化酶活性下降,一氧化氮含量减少,与正常对照组相比差异有显著性(P<0.05);给予洛伐他汀10、20和40μmol/L可明显减轻同型半胱氨酸硫内酯对离体胸主动脉血管环内皮依赖性舒张反应的损伤,使Emax从39.72%±1.91%分别升至54.84%±1.89%、66.25%±1.93%和80.12%±1.32%,半数有效浓度从230.45±13.42nmol/L分别降至145.34±13.19nmol/L、126.93±12.91nmol/L和109.16±14.20nmol/L,一氧化氮水平从0.26±0.04mmol/g分别升至0.51±0.05、0.67±0.03和0.88±0.04mmol/g,同时血管组织中丙二醛含量明显降低,超氧化物歧化酶活性升高,与同型半胱氨酸硫内酯损伤组相比差异均有显著性(P<0.05或P<0.01)。超氧化物歧化酶、N-乙酰半胱氨酸、左旋精氨酸也有和洛伐他汀相类似的抗同型半胱氨酸硫内酯损伤作用,而L-N-硝基精氨酸甲酯可拮抗洛伐他汀的抗同型半胱氨酸硫内酯的损伤作用。结论洛伐他汀能拮抗同型半胱氨酸硫内酯对血管内皮功能的损伤作用,其机制可能与抑制氧化应激、保护血管内皮的一氧化氮合成与释放有关。     

槟榔碱对高糖诱导血管内皮依赖性舒张功能损伤的保护作用

目的 探讨槟榔碱对高糖诱导的内皮依赖性舒张功能损伤的保护作用及其可能的机制.方法 采用离体血管环灌流方法,观察槟榔碱对高糖诱导的大鼠血管内皮依赖性舒张功能损伤的影响以及血管组织中一氧化氮和丙二醛含量以及超氧化物歧化酶活性的影响.同时,观察M受体阻断剂阿托品和一氧化氮合酶抑制剂N-硝基-L-精氨酸甲酯对槟榔碱作用的影响.结果 高糖(44mmol/L)处理组显著降低了乙酰胆碱诱导的大鼠血管内皮依赖性舒张反应,槟榔碱(0.001、0.01和0.1mmol/L)以浓度依赖的方式抑制了高糖诱导的血管内皮依赖性舒张反应损伤.而阿托品和N-硝基-L-精氨酸甲酯取消了槟榔碱的作用.高糖(44mmol/L)处理组显著降低了血管组织中一氧化氮含量和超氧化物歧化酶活性而增加了血管组织中丙二醛含量,槟榔碱(0.1mmol/L)逆转了高糖的这种作用.结论 槟榔碱抑制了高糖诱导的血管内皮依赖性舒张功能损伤,其机制可能与槟榔碱能激动M受体,增加一氧化氮的释放,抑制氧化应激有关.     

同型半胱氨酸硫内酯致血管内皮功能损伤机制与过氧化体增殖物激活型受体γ的相关性

目的 探讨同型半胱氨酸硫内酯所致血管内皮功能损伤机制与过氧化体增殖物激活型受体γ活化的关系.方法 以血管内皮依赖性和非内皮依赖性及血管组织和血清的生化参数为观察指标,采用与血管环直接孵育法和在体动物灌胃给药法,观察硫内酯对大鼠血管内皮功能的损伤作用,并探讨其机制.结果 硫内酯(10mmol/L)与离体大鼠胸主动脉共孵60 min能显著降低乙酰胆碱引起的内皮依赖性舒张反应,降低血管组织中一氧化氮含量,升高超氧化物歧化酶活性和丙二醛含量(P<0.01).血管环与硫内酯共孵之前先与罗格列酮(1mmol/L)预孵30 min,能显著改善被硫内酯降低的血管环内皮依赖性舒张反应,恢复血管环组织中一氧化氮含量,抵抗硫内酯诱导的超氧化物岐化酶活性和丙二醛含量的升高(P<0.05或P<0.01).卡托普利(0.03 mmol/L)和夹竹桃麻素(0.03 mmol/L)有与罗格列酮相似的作用.在体实验表明,大鼠接受硫内酯[50 mg/(kg·d)]灌胃8周,导致血管内皮依赖性舒张反应明显降低,血清丙二醛含量显著升高,对氧磷酶1活性和一氧化氮含量显著降低(P<0.01),但血清中总一氧化氮合酶活性、内皮型一氧化氮合酶活性、诱导型一氧化氮合酶活性、红细胞超氧化物岐化酶活性与正常对照组比无明显改变(P>0.05).同时给予罗格列酮[10、20和40 mg/(kg·d)]灌胃8周,可剂量依赖性地保护硫内酯损伤的内皮依赖性舒张反应,降低血清丙二醛含量,升高血清一氧化氮含量和对氧磷酶1活性(P<0.05或P<0.01).卡托普剁[20 mg/(kg·d)]和夹竹桃麻素[200 mg/(kg·d)]灌胃8周,也能保护硫内酯所损伤的血管内皮依赖性舒张反应和恢复硫内酯所改变的生化指标(P<0.05或P<0.01).在离体和在体实验中,各处理因素对硝普钠引起的非内皮依赖性舒张反应无明显影响(P>0.05).结论 同型半胱氨酸硫内酯在体内和体外均可引起血管内皮功能损伤,其机制可能与抑制过氧化体增殖物激活型受体γ的活性或下调其表达,继而诱发体内氧化应激反应有关.     

洛伐他汀对同型半胱氨酸硫内酯所玫大鼠离体胸主动脉内皮损伤的保护作用

目的观察洛伐他汀对同型半胱氨酸硫内酯所致大鼠离体胸主动脉内皮损伤的保护作用并探讨其相关机制。方法用同型半胱氨酸硫内酯与大鼠离体胸主动脉血管环共孵育90min诱导血管内皮损伤，检测血管内皮依赖性、非内皮依赖性舒张反应以及血管组织生物化学指标，观察洛伐他汀对同型半胱氨酸硫内酯诱导的血管内皮功能损伤的影响。结果血管环与同型半胱氨酸硫内酯孵育90min后，乙酰胆碱诱导的内皮依赖性舒张反应明显降低，而硝普钠引起的非内皮依赖性舒张反应无明显改变；血管组织中丙二醛浓度显著增加，超氧化物歧化酶活性下降，一氧化氮含量减少，与正常对照组相比差异有显著性（P〈0．05）；给予洛伐他汀10、20和40μmol／L可明显减轻同型半胱氨酸硫内酯对离体胸主动脉血管环内皮依赖性舒张反应的损伤。使Emax从39．72％&#177;1．91％分别升至54、84％&#177;1．89％、66．25％&#177;1．93％和80．12％&#177;1．32％，半数有效浓度从230．45&#177;13．42nmol／L分别降至145．34&#177;13．19nmol／L、126．93&#177;12．91nmol／L和109．16&#177;14．20nmol／L，一氧化氮水平从0．26&#177;0．04mmol／g分别升至0．51&#177;0．05、0．67&#177;0．03和0．88&#177;0．04mmol／g，同时血管组织中丙二醛含量明显降低，超氧化物歧化酶活性升高。与同型半胱氨酸硫内酯损伤组相比差异均有显著性（P〈0．05或P〈0．01）。超氧化物歧化酶、N-乙酰半胱氨酸、左旋精氨酸也有和洛伐他汀相类似的抗同型半胱氨酸硫内酯损伤作用，而L-N-硝基精氨酸甲酯可拮抗洛伐他汀的抗同型半胱氨酸硫内酯的损伤作用。结论洛伐他汀能拮抗同型半胱氨酸硫内酯对血管内皮功能的损伤作用，其机制可能与抑制氧化应激、保护血管内皮的一氧化氮合成与释放有关。     

丙丁酚对自由基损伤内皮细胞的保护作用与一氧化氮的关系

本文观察了抗氧化剂丙丁酚对外源性氧自由基损伤动脉内皮细胞的保护作用与其对一氧化氨合成释放的关系.结果显示:兔胸主动脉血管环和培养牛主动脉内皮细胞与黄嘌呤+黄嘌呤氧化酶孵育30min后,乙酰胆碱诱导的血管舒张百分率减少,内皮细胞释放一氧化氮的能力降低,脂质过氧化物含量升高。丙丁酚(40、80和120μmol·L(-1))均能保护内皮细胞免受黄嘌呤+黄嘌呤氧化酶损伤,且呈剂量依赖性。丙丁酚的作用可被一氧化氮灭活剂氧化血红蛋白阻断而不能被一氧化氮合成酶抑制剂N-硝基-L-精氨酸阻断。血管内皮一氧化氮合成与效应抑制实验显示:N-硝基-L-精氨酸、氧化血红蛋白和一氧化氮效应拮抗剂美蓝均能使乙酰胆碱诱导的血管环舒张百分率降低。丙丁酚能对抗氧化血红蛋白和美蓝的作用,但对N-硝基-L-精氨酸的作用无影响。表明丙丁酚保护血管内皮细胞免受氧自由基损伤可能与保护内皮细胞释放的一氧化氮活性有关。     

一氧化氮对自发性高血压大鼠血管内皮功能的作用

目的　探讨自发性高血压大鼠 (SHR)内皮舒张功能不全的发生机制。方法　采用体外灌注的方法测定大鼠胸主动脉环对不同浓度乙酰胆碱的舒张反应变化 ,并测定血清中NO-3浓度和动脉组织中环鸟苷酸水平。结果　与魏 凯二氏大鼠 (WKY)比较 ,SHR胸主动脉环对乙酰胆碱的舒张反应明显减弱。左旋硝基精氨酸 (L NNA)可明显抑制大鼠胸主动脉环对乙酰胆碱的舒张反应 ,但并不能消除SHR和WKY对乙酰胆碱舒张反应之间的差异。与WKY比较 ,SHR血中NO-3水平明显降低 (P<0 .0 1) ,动脉组织中环鸟苷酸含量降低 (P<0 .0 1)。结论　SHR内皮依赖的血管舒张功能减低 ;一氧化氮 (NO)的生成或释放不足可能直接参与了SHR血管内皮依赖的舒张功能不全。     

氯沙坦对糖尿病大鼠血浆血管紧张素Ⅱ及胸主动脉内皮功能的影响

为探讨血管紧张素Ⅱ特异性受体 1阻滞剂氯沙坦对血浆血管紧张素Ⅱ及胸主动脉内皮功能的影响 ,腹腔注射链脲佐菌素复制大鼠糖尿病模型 ,分别于第 4、8、16周处死动物 ,取胸主动脉环测定乙酰胆碱引起的内皮依赖性舒张反应 ,并测定血浆血管紧张素Ⅱ浓度。结果发现 ,糖尿病大鼠随病程进展 ,其胸主动脉环乙酰胆碱引起的内皮依赖性舒张反应渐进性下降 ,血浆中血管紧张素Ⅱ浓度升高。提示 ,氯沙坦可明显改善内皮依赖性舒张反应 ,但对血浆血管紧张素Ⅱ浓度无降低作用。     

对氧磷对血管内皮细胞的损伤作用及机制探讨

目的为探讨有机磷酸酯对血管内皮细胞和血管内皮功能是否有直接的损伤作用。方法用不同浓度的对氧磷分别与大鼠离体血管环和培养的人脐静脉单层内皮细胞共孵不同的时间,以乙酰胆碱引起的血管内皮依赖性舒张反应和单层内皮细胞通透性等为观察指标,检测对氧磷对血管内皮的损伤作用。结果对氧磷（36.3nmol/L-36.3μmol/L）与血管环共孵,呈浓度和时间依赖性地显著抑制乙酰胆碱诱导的内皮依赖性舒张反应,而对硝普钠引起的非内皮依赖性舒张反应没有明显的影响。对氧磷与内皮细胞共孵不同的时间,呈浓度和时间依赖性地显著增加单层内皮细胞的通透性。对氧磷在损伤血管内皮的同时也导致了血管组织及细胞培养液中一氧化氮浓度和超氧化物歧化酶活性的降低、脂质过氧化代谢产物丙二醛浓度的升高。加入左旋精氨酸能部分拮抗对氧磷对血管内皮功能的损伤作用,用阿托品预处理则不影响对氧磷的作用。结论该研究提示对氧磷对血管内皮细胞有直接损伤作用,其机制可能与对氧磷诱发氧化应激,进而导致脂质过氧化反应发生和增加内皮细胞的通透性有关。     

果糖制备的糖基化终末产物对大鼠离体血管环舒张功能的损伤作用及氯沙坦的保护机制

目的观察果糖制备的糖基化终末产物对大鼠离体血管环内皮依赖性舒张反应的损伤以及氯沙坦的保护作用和机制。方法用果糖和牛血清白蛋白(BSA)共同孵育制备AGEs;用离体血管环灌流的方法,观察不同浓度氯沙坦对AGEs引起的血管内皮依赖性舒张反应的保护作用;检测血管环中eNOS和AKT的磷酸化表达及NO含量。结果果糖和BSA共同孵育6 d后可得到AGEs,且AGEs可引起血管环对乙酰胆碱诱导的舒张反应下降;10μmol/L和50μmol/L的氯沙坦均可改善内皮依赖的舒张反应。AGEs还明显降低血管环中NO含量和eNOS及AKT磷酸化水平,氯沙坦可恢复上述指标。结论果糖制备的AGEs能降低血管环内皮依赖性舒张反应,而氯沙坦则具有保护作用,其机制与阻断血管内皮细胞AT1受体、活化AKT激酶而改善内皮eNOS活性和降低NO生成有关。     

缬沙坦对2型糖尿病大鼠血管功能损伤的保护作用

目的观察缬沙坦对2型糖尿病大鼠离体胸主动脉、肾动脉、肠系膜动脉舒张功能的保护作用并分析其机制。方法使用雄性大鼠36只随机分为2组,即正常对照组和糖尿病组。糖尿病组给予高糖高脂饮食诱导结合＋STZ注射（40mg／kg体重）制备2型糖尿病模型。造膜成功后随机分为糖尿病＋盐水组和糖尿病＋缬沙坦组,分别给予相应体积生理盐水或缬沙坦10mg·kg-1·d-1灌胃,持续8周后,处死动物取胸主动脉、肾动脉和肠系膜动脉,检测各组血管内皮依赖和非内皮依赖性舒张反应及血管生物化学指标。结果与正常对照组相比,糖尿病＋盐水组大鼠各血管内皮依赖性舒张功能显著下降,表现为Emax值下降和EC50显著升高,糖尿病＋缬沙坦治疗组与糖尿病＋盐水对照组相比,血管内皮依赖性舒张功能显著改善,而硝普钠诱导的非内皮依赖性舒张反应三组差异无统计学意义。自由基测定结果表明,糖尿病引起血管组织发生自由基损伤,表现为丙二醛含量升高,超氧化物歧化酶活性降低,同时一氧化氮含量下降,舒血管功能受损。缬沙坦干预使一氧化氮生成增加,自由基损伤减轻,显著改善了糖尿病造成的血管损伤。结论缬沙坦对2型糖尿病大鼠的胸主动脉、肾动脉及肠系膜动脉的内皮依赖性舒张功能受损均有显著保护作用,作用与其抗自由基生成、促进内皮一氧化氮合成有关。     

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.