枸杞多糖通过核因子κB信号通路对过氧化氢诱导的神经细胞损伤保护作用的研究

目的研究枸杞多糖(LBP)对过氧化氢(H_2O_2)诱导神经细胞PC12损伤的保护作用及分子机制。方法 PC12细胞分为正常对照组(Con)、H_2O_2诱导模型组(H_2O_2)、H_2O_2+75 mg/L LBP组(H_2O_2+LBP 75)、H_2O_2+150 mg/L LBP组(H_2O_2+LBP 150)、H_2O_2+300 mg/L LBP组(H_2O_2+LBP 300)、H_2O_2+300 mg/L LBP+丙二醇甲醚醋酸酯(PMA)组(H_2O_2+LBP 300+PMA)。CCK-8法检测细胞存活率,DCFH-DA探针法检测细胞内活性氧簇(ROS)水平,比色法检测细胞丙二醛(MDA)、超氧化物歧化酶(SOD)和一氧化氮(NO)含量,流式细胞术检测细胞凋亡率,Western blot检测细胞中核因子κB(NF-κB)信号通路相关蛋白表达水平。结果与Con组比较,H_2O_2组细胞存活率降低[(100.00±5.25)%vs(53.37±2.57)%,P0.05]、ROS水平升高[(20.05±2.14)%vs(46.24±3.27)%,P0.05],MDA水平升高[(8.17±0.41)vs(20.06±1.06)mmol/L,P0.05],SOD活性降低[(19.39±1.17)vs(8.42±0.53)U/ml,P0.05],凋亡率升高[(4.82±1.01)%vs(33.62±3.18)%,P0.05]。与H_2O_2组比较,不同浓度LBP能缓解H_2O_2诱导的氧化损伤,减少细胞凋亡,而NF-κB信号通路激活剂PMA可逆转LBP对PC12细胞损伤保护作用。结论 LBP通过抑制NF-κB信号通路活化,对H_2O_2诱导的神经细胞损伤有保护作用。     

热休克蛋白70抑制c-Jun氨基末端激酶通路对H2O2诱导心肌细胞凋亡的保护作用

目的观察热休克蛋白70(HSP70)对H_2O_2诱导乳鼠心肌细胞凋亡的保护作用及其机制。方法培养大鼠心肌细胞,随机分为5组:对照组、H_2O_2组、热休克组、c-Jun氨基末端激酶(JNK)抑制剂组、热休克 JNK抑制剂组。生化法测定各组细胞培养液中乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)、肌酸激酶(CK)活性和丙二醛(MDA)水平,流式细胞仪分析心肌细胞凋亡,噻唑蓝(MTr)法测定心肌细胞相对活力,Western blot法检测JNK的表达。结果H_2O_2组LDH、MDA水平和CK活性明显高于其他组(P<0.01),而SOD活性则明显低于其他组(P<0.01)。细胞凋亡率H_2O_2组明显高于其他各组(P<0.01)。细胞活力H_2O_2组明显低于对照组(P<0.01),而热休克组、JNK抑制剂组、热休克 JNK抑制剂组的细胞活力明显高于H_2O_2组(P<0.01)。JNK只在H_2O_2组有表达。结论HSP70对H_2O_2诱导的心肌细胞凋亡具有保护作用,其机制可能是HSP70大量表达后抑制了JNK信号的转导。     

卡巴胆碱对烫伤大鼠口服补液时小肠TNF-α及水通道蛋白-1的影响

目的:研究拟胆碱药卡巴胆碱对烫伤大鼠口服补液时小肠TNF-α及水通道蛋白-1(AQP-1)表达的影响.方法:♂Wistar大鼠50只,随机分为假烫(N)、单纯烫伤(S)、肠内葡萄糖-电解质液(GES)、肠内卡巴胆碱组(CAR)和肠内葡萄糖-电解质液 卡巴胆碱组(GES/CAR)5组(n=10).大鼠背部用沸水造成35%TBSA烫伤.N,GES和GES/CAR组于伤后30 min开始补液.免疫组化法测定肠组织AOP-1的表达,ELISA法检测肠组织TNF-α含量,酚红法测定大鼠小肠对水的吸收率.结果:S组大鼠小肠AQP-1与N组比明显降低(90.3±1 8.4 vs 4851.6±654.5,P<0.01);CAR,GES和GES/CAR组AQP-1与S组相比均显著增加(1806.1±110.1,2272.3±113.8,3322.0±595.9 vs 90.3±18.4.均P<0.01).给予卡巴胆碱组(CAR,GES/CAR)与未给予卡巴胆碱组(S,GES)相比肠组织TNF-α含量明显下降(0.9±0.3,1.0±0.47 vs 1.8±0.3,1.9±0.2,P<0.05).GES/CAR,CAR及S组AOP-1表达量与TNF-α含量成负相关(r=-0.9030,-0.9602,-0.9866,均P<0.05).GES/CAR组水吸收率较GES组明显升高(21.0%±0.1%vs 12.7%±0.1%,P<0.05).结论:卡巴胆碱可抑制促炎因子TNF-α的释放,上调小肠AQP-1表达,改善大鼠烫伤早期肠道对水的吸收.     

Tempol对过氧化氢致RAW264.7巨噬细胞氧化损伤的保护作用

目的:研究4-羟基-2,2,6,6-四甲基哌啶(Tempol)对过氧化氢(H_2O_2)引起的RAW264.7巨噬细胞氧化损伤的影响。方法:建立H_2O_2诱导的RAW264.7巨噬细胞氧化损伤模型,分为空白对照组、H_2O_2损伤组(0.2 mmol/L H_2O_2)、低剂量Tempol组(0.2 mmol/L H_2O_2+0.4 mmol/L Tempol)和高剂量Tempol组(0.2 mmol/L H_2O_2+0.8mmol/L Tempol),测定每组细胞培养上清液中丙二醛(MDA)含量、超氧化物歧化酶(SOD)和乳酸脱氢酶(LDH)活性。结果:与空白对照组相比,H_2O_2损伤组培养上清中MDA含量和LDH活性显著升高,SOD活性显著降低(P均0.05)。与H_2O_2损伤组相比,低剂量Tempol组与高剂量Tempol组细胞培养上清中MDA的含量[(7.27±0.35)nmol/mL和(7.27±0.26)nmol/mL对(9.55±0.31)nmol/mL,P均0.05]和LDH的活性[(509.36±38.73)U/L和(492.81±40.36)U/L对(706.24±48.46)U/L,P均0.05]均显著降低,而SOD的活性[(24.84±0.54)U/mL和(24.84±0.28)U/mL对(21.16±0.61)U/mL,P均0.05]均显著升高。低剂量Tempol组和高剂量Tempol组MDA含量、SOD和LDH活性无明显差异,Tempol的作用不呈剂量依赖性。结论:Tempol可能通过调节细胞氧化还原系统,对H_2O_2引起的RAW264.7氧化损伤起到保护作用。     

不同浓度脂联素对心肌细胞氧化应激损伤后GRP78及Caspase-12表达的影响及意义

目的 通过原代培养SD大鼠的乳鼠心肌细胞建立H_2O_2心肌细胞氧化应激损伤模型,观察脂联素对心肌细胞氧化应激所致内质网应激的保护作用.方法 采用酶消化法原代培养乳鼠心肌细胞,倒置相差显微镜下观察细胞生长状态,通过α-肌动蛋白免疫荧光法对培养的心肌细胞进行鉴定.选用原代培养3～4天的心肌细胞,随机分为对照组、H_2O_2组、H_2O_2+10 mg/L脂联素组、H_2O_2+20 mg/L脂联素组和H_2O_2+30 mg/L脂联素组.实验终止后,在倒置相差显微镜下观察心肌细胞形态的变化,采用化学比色法测定乳酸脱氢酶的释放,通过流式细胞术来检测心肌细胞的凋亡,用RT-PCR与western Blotting方法检测内质网应激指标GRP78和Caspase-12的表达.结果 与对照组相比,给予H_2O_2后,细胞凋亡率显著增加(70.7%±6.4%比1.0%±0.6%,P<0.05),LDH释放增加(1411.5 ±189.7 U/L比353.3 ±50.3 U/L,P<0.05),内质网伴侣蛋白GRP78以及Caspage-12在mRNA(分别为1.25±0.50比0.18 ±0.10和1.32±0.15比0.26±0.06)及蛋白水平(分别为0.92±0.50比0.37±0.10和1.24 ±0.50比0.51±0.01)表达增加(P<0.05),30 mg/L脂联素预处理后给予H_2O_2,可较大程度地逆转上述指标变化,细胞凋亡率显著下降(43.6%±3.8%),LDH释放减少(686.7±61.1 U/L),内质网伴侣蛋白GRP78以及Cagpase-12在mRNA(分别为0.56±0.03和0.83±0.04)及蛋白水平(分别为0.66±0.03和0.64±0.03)表达减少(P<0.05).结论 氧化应激使GRP78和Caspase-12表达增强,启动内质网应激,脂联素可以通过减轻内质网应激逆转H_2O_2所致的心肌细胞损伤及凋亡作用,对心肌细胞有保护作用.     

芹菜素对H2O2诱导人肝细胞L02氧化损伤模型的影响

目的探索芹菜素对H_2O_2致人肝细胞L02损伤模型的保护作用。方法以H_2O_2诱导L02细胞建立氧化损伤模型,CCK-8法检测细胞存活率,DCFH-DA法检测细胞活性氧的生成,试剂盒检测细胞上清液中乳酸脱氢酶(LDH)、丙二醛(MDA)及超氧化物歧化酶(SOD)活性,Hoechst染色观察细胞凋亡情况,试剂盒检测caspase-3的活性。计量资料多组间比较采用单因素方差分析,进一步两两比较采用LSD-t检验。结果芹菜素浓度为≥20μmol/L时对L02细胞的增殖有显著抑制作用(P值均001);与空白对照组L02细胞活力相比,500μmol/L及以上的H_2O_2浓度均可使细胞活力极显著降低(P值均0.001),500μmol/L为H_2O_2的建模浓度;模型组细胞活力与空白对照组相比差异显著(P0.01),与模型组相比,芹菜素5、10μmol/L组细胞存活率显著提高(P值均0. 01);空白对照组细胞状态较好,模型组细胞间收缩变圆,细胞破损变形严重,芹菜素5μmol/L组与模型组相比,明显得到改善,变圆破损细胞较少;空白对照组、模型组、芹菜素5μmol/L组3组间相对荧光强度比较差异有统计学意义(1. 00±026 vs 32.94±1. 29 vs 13. 49±1. 23, F=1.10,P0. 001),模型组相对荧光强度较空白对照组明显增强(P0. 001),芹菜素/L组与模型组比较,芹菜素可明显清除H_2O_2诱发的ROS(P0.001);模型组中LDH和MDA水平均明显升高,SOD水平明显降低,与正常对照组相比差异均有统计学意义(F值分别为3.21、2.03、3.32,P值均0. 05),芹菜素(5μmol/L)处理后,与模型组相比,LDH和MDA水平均明显降低,SOD水平明显升高(P值均0. 05);空白对照组、模型组、芹菜素5μmol/L组3组间细胞凋亡率比较差异有统计学意义(7. 54%±0. 52%vs 39. 77%±3. 44%vs 14. 40%±0. 79%,F=9.44,P 0. 01);模型组细胞凋亡率显著高于对照组(P 0. 01);给与芹菜素处理后,相比于模型组凋亡率明显降低(P0. 01);空白对照组、模型组、芹菜素5μmol/L组3组间caspase-3活性比较差异有统计学意义[(4. 38±0. 59)U/mg vs(16. 44±1. 13)U/mg vs(10. 60±1. 04)U/mg,F=1.17,P005],模型组细胞caspase-3活性与对照组相比明显增强(P 005),芹菜素处理后,相比于模型组caspase-3活性明显降低(P005)。结论芹菜素可能通过消除ROS的生成、降低caspase-3活性对H_2O_2诱导的L02细胞损伤产生保护作用。     

miR-19b对H_2O_2诱导的大鼠心肌细胞H9c2氧化应激损伤的保护作用及机制研究

目的研究microRNA(miR)-19b是否在H_2O_2诱导的心肌细胞的氧化应激损伤中具有保护作用。方法将大鼠H9c2心肌细胞株分为6组,空白对照组(L1),H_2O_2组(L2),H_2O_2+miR-19b mimic阴性对照(NC)组(L3),H_2O_2+miR-19b mimic组(L4),H_2O_2+miR-19b inhibitor组(L5),H_2O_2+miR-19b inhibitor NC组(L6)。NC组细胞转染随机合成的miRNA片段作为阴性对照。采用CCK8和流式细胞术检测细胞活性和凋亡情况,逆转录聚合酶链式反应(RT-PCR)法检测miR-19b的表达量,并利用试剂盒检测超氧化物歧化酶(SOD)、乳酸脱氢酶(LDH)、丙二醛(MDA)和还原型谷胱甘肽(GSH)水平,Western blot法检测核因子相关因子2(Nrf2)、血红素氧合酶-1(HO-1)表达水平。结果与L1组比较,L2组和L3组中miR-19b表达量、H9c2细胞活性和细胞内SOD、GSH水平均显著降低(P0.01),细胞凋亡率和细胞内LDH、MDA水平、Nrf2和HO-1表达水平均显著增加(P0.01)。与L2组及L3组比较,L4组中miR-19b表达量、H9c2细胞活性和细胞内SOD、GSH水平、Nrf2和HO-1表达水平均显著增加(P0.01),细胞凋亡率和细胞内LDH、MDA水平均显著降低(P0.01),L5组中miR-19b表达量和H9c2细胞活性和细胞内SOD、GSH水平、Nrf2和HO-1表达水平均显著降低(P0.01),细胞凋亡率和细胞内LDH、MDA水平均显著增加(P0.01),L6组miR-19b表达量、H9c2细胞活性、细胞凋亡率、细胞内SOD、GSH、LDH、MDA水平以及Nrf2和HO-1表达水平均未见统计学差异(P0.05)。结论 miR-19b高表达可显著抑制H9c2细胞的氧化应激损伤,发挥心肌细胞保护作用。     

右美托咪定对过氧化氢引起的PC12细胞损伤的保护作用

目的探讨右美托咪定对过氧化氢(H_2O_2)引起的PC12细胞损伤的保护作用。方法 PC12细胞随机分为正常对照组,H_2O_2组(200μmol/L H_2O_2),右美托咪定低、中、高浓度组(50、100、200μmol/L右美托咪定+200μmol/L H_2O_2),培养48 h,分别检测细胞活力、凋亡情况、天冬氨酸蛋白水解酶(Caspase)3、Caspase9活性、乳酸脱氢酶(LDH)释放量,丙二醛(MDA)含量,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)及谷胱甘肽过氧化物酶(GSH-Px)活性、B淋巴细胞瘤(Bcl)-2及Bcl-2相关X蛋白(Bax)蛋白表达、细胞外调节蛋白激酶(ERK)1/2磷酸化水平。结果与H_2O_2组比较,右美托咪定低、中、高浓度组细胞活力显著提高,细胞早期及晚期凋亡率显著降低,LDH释放量显著减少,MDA含量显著降低,SOD、CAT及GSH-Px活性显著升高,Caspase3、9活性显著降低,Bcl-2及p-ERK1/2表达量显著上调,Bax表达量显著下调(均P<0.01)。结论右美托咪定能通过抗氧化及抗细胞凋亡进而抑制H_2O_2引起的PC12细胞损伤。     

人参入血成分对过氧化氢损伤的心肌细胞的保护作用

目的探讨人参入血成分对过氧化氢(H_2O_2)损伤的心肌细胞的保护作用及机制。方法采用H_2O_2损伤的原代乳鼠心肌细胞模型,将细胞随机分成正常细胞组(Sham)、H_2O_2损伤细胞组(H_2O_2)、人参入血成分含药血清5 min组(SFP 5 min)、人参入血成分含药血清10 min组(SFP10 min)、入血成分组2%组(SFY2%)、入血成分组5%组(SFY5%)。Sham组为10%胎牛血清的DMEM;H_2O_2组为终浓度200μmol/L H_2O_2的10%胎牛血清的DMEM;SFP5 min组为终浓度200μmol/L H_2O_2的10%5 min含药血清的DMEM;SFP10 min组为终浓度200μmol/L H_2O_2的10%10 min含药血清的DMEM;SFY2%组为终浓度200μmol/L H_2O_2的2%移行成分和10%胎牛血清的DMEM;SFY5%组为终浓度200μmol/L H_2O_2的5%移行成分和10%胎牛血清的DMEM。经作用后检测各组心肌细胞存活率、自主搏动频率、乳酸脱氢酶(LDH)、丙二醛(MDA)、超氧化物歧化酶(SOD)、钙含量的差异及Na+-K+-ATP酶、Ca~(2+)-ATP酶活性变化。结果人参入血成分能明显提高H_2O_2损伤心肌细胞的存活率、自主搏动频率、SOD含量,减少心肌细胞MDA含量和LDH的漏出量,降低细胞内游离钙活性的异常升高,改善Na+-K+-ATP酶、Ca2+-ATP酶活性的降低(P0.05,P0.01,P0.001)。结论人参入血成分能够通过保护细胞膜的完整性,抗氧化损伤、对抗钙超载、调整心肌细胞的能量代谢、抑制心肌细胞凋亡而对损伤心肌细胞起保护作用。     

艾地苯醌抑制氧化应激所致皮层神经细胞凋亡的机制

目的探讨艾地苯醌抗氧化应激所致的皮层神经细胞凋亡的机制。方法采用不同浓度过氧化氢(H_2O_2)诱导皮层神经细胞损伤;MTT法测定细胞损伤程度。Western印迹检测蛋白表达变化。结果(1)不同浓度H2O2(0.1,0.3,0.5,0.7 mmol/L)处理原代培养的皮层神经细胞24 h后,细胞死亡率呈浓度依赖性,0.5 mmol/L H_2O_2可使细胞的死亡率达50%;经0.5 mmol/L H_2O_2处理3 h、6 h和24 h后,细胞死亡率呈时间依赖性增高,与正常对照组比较24 h时增加明显(P<0.01)。(2)不同浓度的艾地苯醌(1~50μmol/L)预处理原代培养的皮层神经细胞2 h后,分别用0.5 mmol/L H_2O_2损伤细胞,乳酸脱氢酶(LDH)释放率随艾地苯醌剂量的增加而降低,在10μmol/L时LDH释放率与H2O2损伤组比较下降最显著(P<0.01),随后随艾地苯醌剂量的增加LDH释放率反而升高。(3)用0.5 mmol/L H_2O_2损伤皮层神经细胞后p53蛋白水平的升高可被提前2 h加入的10μmol/L艾地苯醌所抑制。结论艾地苯醌通过降低p53蛋白水平实现抗氧化作用。     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

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.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

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.     

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.     

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.