CRF通过CRF2受体介导肠上皮细胞中TLR4的表达

目的:研究促肾上腺皮质释放因子(CRF)介导肠上皮细胞中Toll样受体4(toll-like receptor4,TLR4)的表达,并探讨其可能通过的受体途径.方法:常规培养人结肠上皮细胞株HT-29细胞,将HT-29细胞分为正常对照组(不加刺激剂),脂多糖(lipopolysaccharide,LPS)刺激组(LPS20g/L刺激24h),促肾上腺皮质释放因子(corticotrophin-releasing factor,CRF)刺激组(CRF20g/L刺激24h),CRF+LPS刺激组(预先CRF20g/L刺激12h,更换细胞液后再与LPS20g/L刺激12h),CRF+Antalarmin 组(CRF与Antalarmin20g/L共刺激24h),CRF+LPS+Antalarmin组(CRF与Antalarmin20g/L共刺激12h后再以LPS刺激12h),CRF+Astressin2B组(CRF与Astressin2B20g/L共刺激24h),CRF+LPS+Astressin2B组(CRF与Astressin2B20g/L共刺激12h后再以LPS刺激12h).刺激结束后,收取各组HT-29细胞,RT-PCR法和免疫印迹法检测各组上皮细胞中TLR4mRNA和蛋白的表达.ELISA法检测各组细胞上清液中IL-8的表达.结果:CRF可以诱导人结肠上皮细胞株HT-29细胞中TLR4表达导致IL-8分泌增多(P<0.05),C R F1受体拮抗剂不能有效地阻滞C R F对TLR4的诱导(P>0.05,CRF+LPS组vs CRF组),CRF2受体拮抗剂可阻滞CRF对TLR4的诱导(P<0.05,CRF+LPS组vs CRF组).结论:CRF通过CRF2受体通路介导肠上皮细胞中TLR4的表达.     

辛伐他汀对脓毒症大鼠肺组织诱导型一氧化氮合酶表达的影响

目的:探讨辛伐他汀对脓毒症大鼠肺组织诱导型一氧化氮合酶(iNOS)表达的影响.方法:90只健康SD大鼠随机分为对照组(生理盐水2 mL静脉滴注)、内毒素(LPS)组(LPS 5 mg/kg,用生理盐水稀释至2 mL静脉滴注)、LPS+辛伐他汀(Sta)组(LPS 5mg/kg,Sta 20mg/kg,生理盐水稀释至2 mL静脉滴注),每组30只.分别在用药后2、4、6、12、24 h处死大鼠,取右肺下叶用RT-PCR法检测肺组织iNOS mRNA表达.结果:光镜下对照组各时点肺泡结构正常;LPS组2h出现炎症损伤,以6h最为显著;LPS+ Sta组中性粒细胞浸润较LPS组减轻.LPS组iNOSmRNA表达较对照组和LPS+ Sta组明显增高(均P＜0.05),6h达高峰,12 h开始下降;LPS+ Sta组各时点iNOSmRNA表达趋势同LPS组,但接近对照组水平(P＞0.05).结论:辛伐他汀能改善脓毒症时肺组织的病理性炎症损伤,辛伐他汀能减低脓毒症时肺组织iNOS mRNA的表达.     

弓形虫诱导巨噬细胞COX-2的表达增加PGE2合成

目的 探讨弓形虫侵染巨噬细胞过程中前列腺素E2(PGE2)的产生途径。方法 用LPS及弓形虫作用于小鼠RAW264．7巨噬细胞系。用气相色谱、ELISA方法分别检测培养上清液中PGE2及花生四烯酸(AA)含量；用RT—PCR及Western blot方法分别检测环加氧酶—l(COX—1)、环加氧酶—2(COX—2)的mRNA及蛋白质表达水平；特异性抑制剂阻断作用于细胞后检测PGE2含量，COX—l／COX—2的mRNA及蛋白质表达。结果 PGE2的合成在弓形虫侵染巨噬细胞4—8h开始升高，12--l6h后达到饱和水平；COX—2mRNA表达在4—8h出现最高峰，在特异性COX—2抑制剂Nimesulide及Indomethacin作用下其表达水平下降，而蛋白质表达水平不受影响。COX—l的mRNA及蛋白质表达在抑制剂处理前后及不同的时间点都末见明显变化。结论 弓形虫可能通过诱导巨噬细胞表达COX—2增加PGE2的合成。     

辛伐他汀抑制人外周血单核巨噬细胞脂蛋白相关磷脂酶A2表达

目的 观察辛伐他汀对人外周血单核巨噬细胞脂蛋白相关磷脂酶A2(Lp-PLA2)表达的影响,并探讨其调控机制.方法 分离培养人外周血单核巨噬细胞,实验分为脂多糖(LPS)组、辛伐他汀组和丝裂原活化蛋白激酶(MAPK)干预组.LPS组:分别用不同浓度(0、1、10、102、103和104ng/ml)的LPS与细胞共同孵育6 h,观察不同浓度的辛伐他汀对LPS诱导的Lp-PLA2 mRNA和蛋白表达的影响;并用1μg/ml的LPS与细胞孵育不同时间(0、6、12、24和48 h),观察辛伐他汀作用不同时间对LPS诱导的Lp-PLA2 mRNA和蛋白表达的影响.辛伐他汀组:1 μg/ml的LPS+不同浓度的辛伐他汀(10-2～10-7mmol/L)与单核巨噬细胞共同孵育24 h,1 μg/ml LPS+10-3mmol/L的辛伐他汀与单核巨噬细胞孵育不同时间(0、6、24、24和48 h),观察辛伐他汀对LPS诱导的Lp-PLA2mRNA和蛋白表达及酶活性的影响.MAPK组:分别用10 μmol/L的p38抑制剂SB203580、20 μmol/L的ERK抑制剂U0126和20 μmol/L的JNK抑制剂SP600125预处理30 min后,将单核巨噬细胞与1μg/ml的LPS共同孵育24 h,观察MAPK信号通路在LPS介导的Lp-PLA2表达中的作用.逆转录-多聚酶链反应(RT-PCR)方法 检测Lp-PLA2 mRNA表达,比色法测定酶活性,Western blot方法 检测Lp-PLA2蛋白表达以及p38-MAPK蛋白及磷酸化水平.结果 (1)0.1μg/ml的LPS刺激6 h即可显著增加单核巨噬细胞Lp-PLA2 mRNA和蛋白的表达及其酶活性,并且随LPS浓度的增加和刺激时间的延长,该作用增强.(2)辛伐他汀可以明显抑制LPS诱导的Lp-PLA2的表达增加,并且降低酶活性,该作用呈浓度及时间依赖性.(3)辛伐他汀抑制LPS诱导的p38MAPK蛋白活化,p38MAPK的抑制剂SB203580可以完全阻断LPS介导的Lp-PLA2蛋白表达增加,与辛伐他汀作用相似.而MEK1/2的抑制剂U0126和JNK的抑制剂SP600125对LPS介导的Lp-PLA2蛋白表达的增加没有影响.结论 在培养的人外周血单核巨噬细胞中,辛伐他汀可以明显抑制LPS诱导的Lp-PLA2 mRNA和蛋白表达,降低Lp-PLA2酶活性,该作用至少部分由抑制p38MAPK信号转导通路介导.     

贝母素甲对内毒素性急性肺损伤小鼠炎症因子表达的影响

目的探讨贝母素甲(PM)对脂多糖(LPS)诱导小鼠急性肺损伤过程中炎症因子表达的影响。方法 80只昆明种小鼠体重(20±5)g随机分成正常组、模型组、地塞米松(Dex)组、PM组,腹腔注射戊巴比妥(40 mg/kg)麻醉小鼠,模型组、Dex组及PM组小鼠给予气管内注射4 mg/kg LPS诱导建立急性肺损伤模型。注入LPS前1、12、24 h和36 h和注入后12 h,24 h和36 h,模型组、Dex组、PM组动物分别给予生理盐水、10 mg/kg盐酸地塞米松、1 mg/kg PM溶液,正常组给予同等体积生理盐水。实验结束后解剖肺脏,观察肺脏形态学改变,分别用Real-Time PCR和酶联免疫吸附试验(ELISA)测定肿瘤细胞坏死因子(TNF)-α、白介素(IL)-2、IL-6和IL-8。结果 LPS能明显引起小鼠肺部的炎症反应,PM处理后拮抗了LPS对小鼠肺组织的破坏作用,抑制促炎因子TNF-α、IL-2、IL-6、IL-8的表达。结论 PM对急性肺损伤小鼠肺组织保具有保护作用,其机制可能与下调炎症因子的表达有关。     

环氧合酶-2抑制剂对大鼠胃黏膜损伤愈合的影响

目的　环氧合酶 (COX)是合成前列腺素 (PGs)的关键酶 ,传统的非甾体抗炎药 (NSAIDs)抑制COX 1和COX 2活性 ,引起严重的胃肠道不良反应。特异性COX 2抑制剂有望成为不引起胃损伤的新型NSAIDs。本研究探讨特异性和非特异性COX 2抑制剂对盐酸诱导大鼠胃黏膜损伤愈合的影响。方法　雄性SD大鼠胃内给予 0 .6mol/LHCl1ml,Westernblot和免疫组化法分析胃黏膜COX 1和COX 2表达。盐酸灌胃后 10min ,实验组胃内给予NS 3980 .4、4、4 0mg/kg和吲哚美辛 4 0mg/kg ,对照组胃内给予 1%阿拉伯树胶 (AG) 5ml/kg。盐酸灌胃前和灌胃后 1、3、6、12、2 4及 4 8h分别处死大鼠 ,剖腹取胃 ,观察各组动物损伤指数 (LI)及光镜下的胃黏膜病理学改变。结果　盐酸灌胃后COX 2在表层上皮细胞和颈黏液细胞表达显著增加 ,NS 398和吲哚美辛均延迟胃黏膜损伤的愈合。盐酸灌胃后 12h ,NS 398组 (4和 4 0mg/kg)及吲哚美辛组的LI分别为 (1.4 2± 0 .2 3) % ,(1.4 2± 0 .2 9) %和 (1.6 2± 0 .4 4 ) % ,明显高于对照组的 (0 .5 8± 0 .2 4 ) % (P <0 .0 5 )。结论　特异性和非特异性COX 2抑制剂延迟大鼠胃损伤后的愈合 ,提示COX 2表达在胃黏膜再生过程中起重要作用     

小檗碱对脂多糖诱导的COX-2表达的影响

目的:研究中药小檗碱对脂多糖(LPS)诱导的COX-2表达的影响。方法:取人外周静脉血分离及培养单个核细胞,分为3组:空白对照组、LPS组、LPS+小檗碱组。分别在培养后30 min,6 h,12 h,24 h提取细胞,行RT-PCR法测定COX-2 mRNA水平,Western blot法测定p38MAPK,p-p38MAPK,ERK,p-ERK及COX-2蛋白水平。同时加入选择性p38MAPK抑制剂(SB203580),以及特异性ERK抑制剂(PD098059)分别测定COX-2 mRNA及蛋白水平。结果:与空白对照组相比,LPS组COX-2 mRNA及蛋白表达明显增强(P<0.01)。与LPS组相比,LPS+小檗碱组COX-2 mRNA及蛋白表达明显抑制(P<0.05),且随着浓度增加,抑制作用更明显,在给药后12 h,小檗碱对COX-2抑制作用最强。与LPS组相比,LPS+小檗碱组P38MAPK活性水平差异无统计学意义(P>0.05)。但是与LPS组相比,LPS+小檗碱组ERK活性水平差异有统计学意义(P<0.05)。加入p38MAPK抑制剂以及ERK抑制剂之后,COX-2 mRNA及蛋白水平降低明显...     

天然血小板活化因子受体拮抗剂对缺血脑区两型环加氧酶基因表达的影响

目的　探讨大鼠脑缺血再灌注后两环加氧酶异构体 (COX 1和COX 2 )基因表达的变化及天然血小板活化因子 (PAF)受体拮抗剂海风藤新木脂素复合物和银杏内酯对两酶表达的影响。　方法　应用RT PCR技术 ,检测大脑中动脉线栓闭塞再通不同时相大脑中动脉供血区皮质COX 1与COX 2基因的表达水平。　结果　缺血及药物预处理对COX 1mRNA表达水平均无显著影响。单纯缺血 90min时 ,缺血皮质COX 2mRNA表达含量无明显变化 ,密度比值为 0 2 7± 0 0 5 ;再灌注 6h显著升高 ( 0 83± 0 12 ) ,12h最强 ( 1 2 2± 0 19) ,至 4 8h仍较假手术对照组高 ( 0 4 9± 0 0 8)。两种PAF受体拮抗剂均能显著抑制缺血再灌注 12hCOX 2基因的表达增高 ( 0 5 8± 0 11和 0 6 8±0 13)。　结论　脑缺血再灌注可诱导COX 2基因表达增强 ;PAF是COX 2基因表达的上游信号分子 ,抑制COX 2基因高表达可能是海风藤新木脂素复合物及银杏内酯的脑保护分子机制之一。     

脂多糖诱导肺泡上皮细胞炎性损伤及损伤机制

目的 探讨细菌脂多糖(LPS)诱导的肺泡上皮细胞(AEC)炎症反应及可能的反应机制.方法 将人肺腺癌细胞系A549细胞株分为2组:对照组和LPS干预组,分别培养并于0.5 h、2 h、6 h和12 h时留取标本进行相关细胞因子检测.酶联免疫吸附法(ELISA)检测细胞间黏附分子-1(ICAM-1),放射免疫法检测肿瘤坏死因子-α(TNF-α)和白细胞介素-8(IL-8)的水平.实时荧光定量PCR检测TLR-4 mRNA的表达;蛋白质免疫印迹(Western blot)法检测核转录因子-κB(NF-κB)抑制蛋白IκBα和NF-κB p65蛋白水平,观察NF-κB的活性变化.结果 与对照组比较,LPS使AECs分泌的ICAM-1,TNF-α和IL-8于2 h、6 h和12 h均升高,ICAM-1,TNF-α于2 h、IL-8于12 h达分泌高峰;作用2 h后TLR-4 mRNA表达明显升高并达到峰值(27.88±13.31),6 h后(19.82±15.58)仍高于对照组(1.00±0.00),组间比较差异有统计学意义(P＜0.05),12 h时(12.86±11.45)组间比较差异无统计学意义(P＞0.05);NF-κB活性于刺激后0.5 h、2 h、6 h和12 h均明显增加,表现为抑制蛋白IκBα迅速降解,NF-κB p65蛋白同步释出并转入细胞核内.结论 LPS能够激活肺泡上皮细胞使其释放大量炎性因子,这一过程可能是通过激活TLR-4并进而激活NF-κB而诱导了AECs的炎性损伤.

Abstract：

Objective Lipopolysaccharide(LPS)can activate alveolar epithelial cells(AECs)and induce inflammatory injury.Toll-like receptor-4(TLR-4)is integrally involved in LPS signaling and plays a requisite role in the activation of NF-κB.NF-κB is a key intercellular signaling event that mediates cell inflammatory responses.The aim of the study wss to investigate in an in vitro model the inflammatory responses of AECs induced by LPS and the underlying mechanisms.Methods The study was performed on A549 cells(Human lung adenocarcinoma cell line).A549 cells were divided into 2 groups:a control group and a LPS stimulation group.Pminflammatory cytokines ICAM-1,TNF-α and IL-8 were detected by ELISA or radioimmunological methods.The expression of TLR-4 mRNA was detected by real time PCR.The activation of NF-κB was detected by Western blot(proteins of I-κBα and NF-κB p65).Results Compared with the control group.the ICAM-1 and TNF-α levels of the LPS-stimulated group were significantly higher,peaked after 2 h,and then gradually decreased at 6 and 12 h.IL-8 was also significantly increased after 2 h, which continued up to 12 h.The expression of TLR-4 mRNA in the LPS group was significantly higher,peaked after 2 h and gradually decreased at 6 and 12 h.NF-κB was activated after 0.5,2,6 and 12 h,indicated by the significant degradation of IκB-α and the significant release of NF-κB P65 and its subsequent translocation into the nucleus approximately synchronized.Conclusion The results demonstrate that LPS induced inflammatory injury in AECs via activating TLR-4 and subsequently NF-κB.     

促肾上腺皮质激素释放因子对肠上皮细胞紧密连接相关蛋白的调节

目的:探讨促肾上腺皮质激素释放因子(corticotrophin-releasing factor,CRF)对肠上皮细胞紧密连接相关蛋白的调节作用.方法:以CRF(20 ng/mL)刺激HT-29细胞24 h后再以脂多糖(lipopolysaccharides,LPS)(100 ng/mL)刺激24 h,收集细胞,ELISA法检测细胞提取物中胞质附着蛋白(zonula occludins protein,ZO)-1、ZO-2、Occludin、cldn1、cldn2、cldn3和cldn4的表达.再次将HT-29细胞以CRF 0、1、10、20 ng/mL的浓度刺激24 h和核因子B(nuclear factor B,NF-B)抑制剂马来酸二乙酯(diethylmaleate,DEM)1 mmol/L预孵1 h后加CRF 20 ng/mL刺激24 h,然后更换各组细胞液后继续再以LPS 100 ng/mL的浓度孵育24 h,收集各组HT-29细胞,提取蛋白,免疫印迹法检测cldn2表达水平.结果:ELISA检测结果显示以CRF刺激结肠上皮细胞24 h后再以LPS刺激后ZO-1、ZO-2、Occludin、cldn1和cldn3表达水平较单纯LPS刺激有轻度的下降,但是cldn2的表达则较前明显升高(P<0.01).免疫印迹法检测结果显示以LPS孵育前以CRF(1 ng/mL)刺激即可引起cldn2表达增高,随后加大CRF刺激浓度,分别以10和20 ng/mL刺激,则cldn2的表达随着刺激浓度加大而逐渐增高(P<0.05),呈现剂量依赖效应,而以CRF(20 ng/mL)刺激同时加入NF-B抑制剂DEM后再以LPS孵育HT-29细胞后,CRF则不能诱导cldn2表达增高(P>0.05).结论:CRF对肠上皮细胞中的cldn2表达刺激呈剂量依赖效应,并且CRF对肠上皮细胞的这种诱导作用可能与NF-B激活有关.     

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.     

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.     

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.     

Serological survey of HIV and syphilis in pregnant women in Madagascar

Objectives Peripartal transmission of human immunodeficiency virus (HIV) and Treponema pallidum, the causative agent of syphilis, leads to severe consequences for newborns. Preventive measures require awareness of the maternal infection. Although HIV and syphilis testing in Madagascar could be theoretically carried out within the framework of the national pregnancy follow‐up scheme, the required test kits are rarely available at peripheral health centres. In this study, we screened blood samples of pregnant Madagascan women for HIV and syphilis seroprevalence to estimate the demand for systemic screening in pregnancy. Methods Retrospective anonymous serological analysis for HIV and syphilis was performed in plasma samples from 1232 pregnant women that were taken between May and July 2010 in Ambositra, Ifanadiana, Manakara, Mananjary, Moramanga and Tsiroanomandidy (Madagascar) during pregnancy follow‐up. Screening was based on Treponema pallidum haemagglutination tests for syphilis and rapid tests for HIV, with confirmation of positive screening results on line assays. Results Out of 1232 pregnant women, none were seropositive for HIV and 37 (3%) were seropositive for Treponema pallidum. Conclusions Our findings are in line with previous studies that describe considerable syphilis prevalence in the rural Madagascan population. The results suggest a need for screening to prevent peripartal Treponema pallidum transmission, while HIV is still rare. If they are known, Treponema pallidum infections can be easily, safely and inexpensively treated even in pregnancy to reduce the risk of transmission.     

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.     

Variabilité des concentrations plasmatiques de l’angiotensinogène et risque d’hypertension artérielle chez le rat transgénique

Aim

Genetic polymorphisms of the human angiotensinogen gene are frequent and may induce up to 30% increase of plasma angiotensinogen concentrations with a blood pressure increase of up to 5 mmHg. Their role for the pathogenesis of human arterial hypertension remains unclear. High plasma angiotensinogen levels could increase the sensitivity to other blood pressure stressors.

Methods

Male transgenic rats with a 9-fold increase of plasma angiotensinogen concentrations and male non-transgenic rats aged 10 weeks were treated or not with NG-Nitro-L-arginine-methyl ester for 3 weeks in their drinking water (n = 3/group). Systolic blood pressure and body weight were measured at baseline and at the end of the study when left ventricular weight and ventricular expression of angiotensin I-converting enzyme and procollagen Iα1 were determined (polymerase chain reaction).

Results

At baseline, transgenic rats had +18 mmHg higher bood pressure and –8% lower body weight compared to non-transgenic rats (P < 0.05) without significant changes for the vehicle groups throughout the study (P > 0.05). NG-Nitro-L-arginine-methyl ester increased blood pressure, left ventricular weight and left ventricular weight indexed for body weight by +41%, +17.6% and +18.6% (P < 0.05) in transgenic and +25%, +5.3% and +6.7% (P > 0.05) in non-transgenic rats compared to untreated animals, respectively. Cardiac gene expression showed no differences between groups (P > 0.05).

Conclusion

Increased plasma angiotensinogen levels may sensitize to additional blood pressure stressors. Our preliminary results point towards an independent role of angiotensinogen in the pathogenesis of human hypertension and associated end-organ damage.