槲皮素在衣霉素诱导的内质网应激介导肝癌细胞上皮间质转化中的作用

目的探讨槲皮素(Quercetin,Que)在衣霉素(Tunicamycin,TM)诱导的内质网应激介导肝癌细胞上皮间质转化(epithelial mesenchymal transition,EMT)中的作用。方法以衣霉素诱导肝癌细胞HepG2发生内质网应激,细胞分为四组:对照组、衣霉素组、槲皮素组、衣霉素+槲皮素组,采用噻唑蓝法检测细胞活力变化,划痕实验检测细胞迁移距离,PCR和Western blotting法分别检测葡萄糖调节蛋白(GRP78)和EMT因子Snail、E-cadherin及Vimentin的mRNA和蛋白质表达水平。结果槲皮素可显著抑制HepG2增殖;衣霉素组细胞的迁移距离明显大于另外三组(P0.01),槲皮素组小于对照组(P0.01);衣霉素组细胞的GRP78、Snail、Vimentin mRNA及蛋白表达水平显著高于另外三组(P0.05),而E-cadherin低于另外三组(P0.05),与对照组比,槲皮素组GRP78、Snail、Vimentin mRNA及蛋白表达水平降低(P0.05),E-cadherin升高(P0.05)。结论槲皮素可抑制衣霉素诱导的内质网应激及其介导的EMT,从而抑制肝癌细胞增殖转移。     

GRP78在胃癌中表达水平及沉默表达后对人胃癌SGC-7901/DDP细胞增殖和凋亡的影响

目的研究内质网分子伴侣葡萄糖调节蛋白78(glucose regulated protein 78,GRP78)在人不同胃组织(正常胃组织和胃癌组织)和细胞(正常胃上皮GES1细胞、胃癌SGC-7901细胞、多耐药性胃癌SGC-7901/DDP细胞)中的表达水平;揭示GRP78沉默表达对SGC-7901/DDP细胞增殖和凋亡的影响。方法利用实时荧光定量PCR(Real-time PCR)和免疫印迹(Western blotting)方法分别检测人正常胃组织、胃癌组织、人正常胃上皮GES1细胞、胃癌SGC-7901细胞、多耐药性胃癌SGC-7901/DDP细胞中GRP78 mRNA和蛋白表达水平。利用LipfectamineTM2000将GRP78 siRNA转染至SGC-7901/DDP细胞中,同时设置未转染Control组和无义转染Control siRNA组。Real-time PCR和Western blotting方法检测各组SGC-7901/DDP细胞转染效率;MTT方法检测各组SGC-7901细胞的生长活力变化和不同浓度顺铂DDP作用下细胞增殖抑制率;流式细胞术检测各组SGC-7901细胞凋亡情况。结果胃癌组织中GRP78 mRNA和蛋白表达水平显著高于正常胃组织(P0.05);多耐药性胃癌SGC-7901/DDP细胞中GRP78 mRNA和蛋白表达水平显著高于胃癌SGC-7901细胞和正常胃上皮GES1细胞(P0.05);GRP78 siRNA转染SGC-7901/DDP细胞后GRP78 mRNA和蛋白表达水平显著下降(P0.05);与Control组和Control siRNA组相比,GRP78 siRNA转染组SGC-7901/DDP细胞生长活力显著下降,DDP作用下细胞增殖抑制率和细胞凋亡率显著增加(P0.05)。结论 GRP78 mRNA和蛋白在胃癌组织中高表达,在多耐药性胃癌SGC-7901/DDP细胞中也高表达,证实GRP78在胃癌中发挥促癌基因的作用。而GRP78 siRNA转染能够沉默SGC-7901/DDP细胞中GRP78基因表达,抑制SGC-7901/DDP细胞增殖并促进细胞凋亡。     

内质网应激对胃癌细胞迁移与侵袭的影响

目的:探讨内质网应激(endoplasmic reticulum stress,ERS)对胃癌细胞迁移及侵袭能力的影响及其机制.方法:5μg/mL衣霉素处理胃癌细胞系SGC7901或BGC823 0、12、24及36 h,Western blot检测各时间点葡萄糖调节蛋白78(glucoseregulated protein 78,GRP78)、金属基质蛋白酶9(matrix metalloproteinase 9,MMP9)及血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)的表达;划痕实验检测衣霉素处理不同时间后对胃癌细胞迁移能力的影响,各时间点均设未加药对照组;Transwell侵袭实验检测衣霉素处理不同时间后对胃癌细胞侵袭能力的影响,各时间点均设未加药对照组.结果:与相应的0 h组相比,衣霉素处理胃癌细胞系SGC7901或BGC823 12、24及36 h后,GRP78、MMP9及VEGF的蛋白表达量均明显增加(P0.05);衣霉素处理12、24及36 h后,胃癌细胞的划痕愈合度及胃癌细胞侵袭到Transwell下室的细胞数均明显高于0 h组(P0.05).结论:ERS可上调MMP9及VEGF,促进胃癌细胞的迁移与侵袭.     

氧化型低密度脂蛋白诱导分子伴侣GRP78在3T3-L1脂肪细胞中的表达

目的观察氧化型低密度脂蛋白(ox-LDL)诱导3T3-L1脂肪细胞内质网应激相关分子伴侣葡萄糖调节蛋白78(GRP78)的表达,探讨ox-LDL对脂肪细胞内质网应激的诱导作用。方法体外培养3T3-L1脂肪细胞,分别给予不同浓度ox-LDL(50,100,200μg/ml)及内质网应激阳性对照诱导剂衣霉素(Tun)处理。用RT-PCR检测GRP78 mRNA的表达,筛选出最佳干预浓度,用最佳浓度的ox-LDL分别干预脂肪细胞6、12、24 h,分别用RT-PCR、Western印迹法检测GRP78 mRNA、蛋白表达情况。结果 ox-LDL呈浓度依赖方式诱导脂肪细胞GRP78表达,其表达强度随时间延长而增强,24 h达高峰(P<0.05)。结论 ox-LDL可诱导3T3-L1脂肪细胞发生内质网应激,促使未折叠蛋白反应信号通路的分子伴侣表达增加。     

内质网应激对肝细胞过氧化物酶体增殖物激活受体α表达的影响

目的探讨不同严重程度内质网应激对过氧化物酶体增殖物激活受体α(peroxisome proliferator-activated receptor alpha,PPARα)表达的影响。方法以小鼠肝细胞AML-12为研究对象,内质网应激诱导剂衣霉素(Tunicamycin,TM)以时间梯度、浓度梯度细胞诱导不同严重程度的内质网应激。采用实时荧光定量PCR方法和免疫印迹方法检测葡萄糖调节蛋白78(glucose regulated protein 78,GRP78)、CCAAT/增强子结合蛋白同源蛋白(C/EBP-homologous protein,CHOP)、PPARα在内质网应激过程中的基因和蛋白动态表达;用免疫荧光染色方法检测PPARα蛋白在内质网应激过程中的表达情况和位置变化。结果在TM分别以不同时间和不同浓度诱导AML-12细胞内质网应激的过程中,随TM刺激时间延长与浓度增加,CHOP、GRP78 mRNA和蛋白水平也逐渐升高;而PPARαmRNA和蛋白呈现先升高后下降的表达趋势。在免疫荧光检测中,TM刺激早期PPARα主要在细胞质中表达,晚期集中在细胞核内;低浓度TM刺激时PPARα的位置主要表达在细胞质,而高浓度TM刺激后,PPARα聚集在细胞核中。结论细胞轻度内质网应激时,PPARα表达升高,而在细胞严重内质网应激时PPARα表达下降。     

4,4′-二异硫氰基芪-2,2′-二磺酸对内质网应激诱导心肌细胞损伤的影响

目的探讨氯离子通道阻滞剂4,4′二异硫氰基芪2,2′-二磺酸(DIDS)对衣霉素诱导心肌细胞损伤以及内质网应激标记性分子糖调节蛋白78(GRP78)和CCAAT增强子结合蛋白样同源蛋白(CHOP)的影响。方法取乳鼠心肌细胞培养后,应用衣霉素构建心肌细胞内质网应激模型,随机分为对照组、衣霉素组、衣霉素+DIDS组、DIDS组。应用100ng/ml衣霉素处理24、48、72、96 h;另用DIDS 25、50、75和100μmol/L处理72 h,噻唑蓝法检测心肌细胞存活率,Western blot法检测GRP 78和CHOP蛋白表达水平。结果与对照组比较,衣霉素组48、72和96 h心肌细胞存活率明显降低(P<0.05);与衣霉素组比较,DIDS 50、75和100μmol/L处理明显增加心肌细胞存活率(P<0.05)。与对照组比较,衣霉素组GRP78和CHOP蛋白表达水平明显升高(P<0.05);与衣霉素组比较,衣霉素+DIDS组GRP78和CHOP表达水平明显下调(P<0.05)。结论 DIDS可以抑制衣霉素诱导的大鼠心肌细胞损伤,其机制可能与拮抗GRP78和CHOP的表达,减轻内质网应激有关。     

胃泌素对胃癌细胞EMT和Wnt/β-catenin信号通路相关基因表达的影响

目的探讨高表达胃泌素(gastrin)对胃癌细胞上皮间质转化(EMT)的影响及可能机制。方法用gastrin过表达质粒pcDNA3-gastrin及空载体pcDNA3.1转染胃癌细胞SGC-7901、MKN45,48 h后收集细胞蛋白,Western印迹检测鉴定gastrin表达,检测EMT相关标志物E-钙黏蛋白(cadherin)、N-cadherin、Snail及wnt/β-连环蛋白(catenin)信号通路相关基因wnt3α、β-catenin、c-myc的蛋白表达变化。结果在SGC-7901、MKN45细胞中成功过表达gastrin。与pcDNA3.1空载体转染组相比,pcDNA3.1-gastrin转染SGC-7901、MKN45细胞中上皮标志蛋白E-cadherin表达下调,间质标志蛋白N-cadherin、Snail表达上调,差异有统计学意义(P<0.05);同时Wnt/β-catenin通路蛋白相关蛋白wnt3α、β-catenin及其下游基因c-myc的表达上调,差异有统计学意义(P<0.05)。结论过表达gastrin能够激活Wnt/β-catenin信号通路和促进胃癌细胞SGC-7901和MKN45发生EMT。     

轻度氧化低密度脂蛋白对巨噬细胞内质网应激的诱导作用及其信号通路

目的研究巨噬细胞泡沫化过程中轻度氧化低密度脂蛋白(mm-LDL)对巨噬细胞内质网应激的诱导作用及其信号通路。方法体外培养鼠源RAW264.7巨噬细胞,分别给予mm-LDL(25、50和100 mg/L)和衣霉素(TM)处理6、12和24 h。采用油红O染色观察细胞内脂质蓄积情况,酶比色法测定细胞内总胆固醇含量,免疫荧光细胞化学法观测转录激活因子6(ATF6)核转位情况,免疫印迹法检测内质网应激转导子1(IRE1)磷酸化水平和X盒结合蛋白1(XBP1)及内质网分子伴侣糖调节蛋白78(GRP78)蛋白的表达,RT-PCR检测GRP78 mRNA的表达。结果 mm-LDL呈浓度依赖性增加细胞内总胆固醇含量,胞浆内可见大量油红O染色阳性脂质颗粒,以12 h时最为显著;与内质网应激诱导剂TM相似,mm-LDL显著诱导ATF-6由胞浆向细胞核内转移,并上调磷酸化IRE1及其下游信号分子XBP1和GRP78蛋白的表达,且表达强度随着mm-LDL诱导浓度的增加而增强;50 mg/L mm-LDL处理组GRP78 mRNA的表达于作用后6 h即发生显著上调,为对照组的3.7倍,而蛋白表达水平也明显增加,并于12 h达到高峰,此...     

黄芪总皂苷对内质网应激诱导的心肌细胞肥大模型的保护作用

目的观察内质网应激(ERS)对心肌肥大的影响,探讨黄芪总皂苷对ERS诱导的心肌细胞肥大的保护作用。方法心肌细胞原代培养,实验分为对照组、衣霉素(TM)组、黄芪总皂苷联合TM(AST+TM)组。通过测定心肌细胞蛋白质合成速度、心肌细胞表面积观察心肌细胞肥大,通过内质网染色以及RT-PCR检测葡萄糖调节蛋白(GRP78)和C/EBP同源蛋白(CHOP)mRNA的表达观察心肌细胞ERS反应。结果与对照组相比,TM组心肌细胞蛋白质合成速度提高、心肌细胞表面积增加,ERS分子GRP78和CHOP mRNA表达增加,均有显著性差异(P0.01),内质网形态改变与TM组相比,AST+TM组心肌细胞蛋白质合成速度降低、心肌细胞表面积减小,GRP78和CHOP mRNA表达降低,均有显著性差异(P0.01),内质网形态恢复,与对照组类似。结论 ERS诱导剂TM诱导心肌细胞显著肥大,同时伴随ERS反应,黄芪总皂苷可以通过减弱ERS反应而抑制TM诱导的心肌细胞肥大。     

原人参二醇对胃癌诱导血管内皮细胞增殖的抑制作用

目的 探讨原人参二醇(Ppd)对胃癌诱导血管内皮细胞(VEC) 增殖的抑制作用.方法 采用MTT 法检测不同浓度Ppd对VEC、人胃癌SGC-7901 细胞增殖及SGC-7901细胞诱导VEC增殖的影响.结果 Ppd对VEC、人胃癌SGC-7901 细胞生长有明显的抑制作用,且呈量效关系,IC_(50)为2.0 μg/ ml,且肿瘤细胞产生明显的G_1期阻滞现象,Ppd为2.0 μg/ml时,G_1细胞百分率达76.08%,而在Ppd为10.0 μg/ml时为81.17%,较对照组39.02%明显增多(P<0.05),而S期、G2+M期细胞数明显减少.Ppd浓度为2.0 μg/ml时,对SGC-7901细胞条件培养液诱导的VEC增殖有抑制作用(P< 0.01),抑制率为13.10 %～77.38 %.结论 Ppd对胃癌细胞条件培养液诱导的VEC 增殖具有抑制作用.     

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.