肾素通过非血管紧张素Ⅱ途径促进大鼠血管平滑肌细胞钙化

目的 探讨肾素通过非血管紧张素Ⅱ(AngⅡ)途径对大鼠血管平滑肌细胞钙化的影响及其可能的分子机制.方法 采用组织块贴壁法培养原代大鼠主动脉平滑肌细胞,利用β-甘油磷酸钠联合丙酮酸钠制备血管平滑肌细胞钙化模型.细胞随机分为6组:空白对照组(予常规培养基)、钙化组(予钙化培养基)、钙化+ AngⅡ受体阻断剂组(予钙化培养基,再予氯沙坦10-6 mol/L和PD123,31910-5 mol/L分别阻断AngⅡ受体AT1、AT2)、钙化+肾素(10-10、10-9和10-8 mmol/L)组(于钙化培养基中,先加入氯沙坦10-6 mol/L和PD123,319 10-5 mol/L,再分别予10-10、10-9和10-8 mmol/L肾素).用Von Kossa染色鉴定钙化细胞,测定各组细胞中钙含量、碱性磷酸酶(ALP)活性判断钙化程度.用RT-PCR检测成骨细胞标志物核结合因子α1(Cbfα1)和转化生长因子β1 (TGF-β1) mRNA表达,Western blot测定各组细胞Cbfα1蛋白含量.结果 与空白对照组相比,钙化组钙含量、ALP活性显著增加,Cbfα1和TGF-β1 mRNA及Cbfα1蛋白表达明显增加(P＜0.01).与钙化组相比,钙化+AngⅡ受体阻断剂组对钙化的影响无统计学差异.与钙化+ AngⅡ受体阻断剂组相比,钙化+肾素(10-10、10-9和10-8 mmol/L)组呈剂量依赖地促进大鼠血管平滑肌细胞的钙含量、ALP活性,以及Cbfα1和TGF-β1 mRNA及Cbfα1蛋白表达(P＜0.05).结论 肾素可通过非AngⅡ途径作用促进β-甘油磷酸钠诱导的血管平滑肌细胞钙化,其作用可能与TGF-β1、Cbfα1表达上调有关.     

维生素K_2对大鼠血管平滑肌细胞钙化及Toll样受体2和4表达的影响

目的探讨维生素K_2对血管平滑肌细胞(VSMC)钙化及Toll样受体(TLR)2和TLR4表达的影响。方法体外培养A7r5VSMC分为正常组(基础培养液),钙化组(加入10mmol/Lβ磷酸甘油),干预组(钙化基础上加入维生素K_210-6 mmol/L),各组均干预14d。Von Kossa染色观察VSMC钙化发生情况;检测细胞钙含量和碱性磷酸酶(ALP)活性;实时定量PCR及Western blot检测TLR2和TLR4mRNA和蛋白表达水平。结果钙化组细胞钙含量及ALP活性较正常组分别增加11.5倍和9.3倍(P<0.01);干预组细胞钙含量及ALP活性较钙化组分别减少1.5倍和2.3倍(P<0.01)。与正常组比较,钙化组细胞TLR2、TLR4蛋白及mRNA表达升高;与钙化组比较,干预组细胞TLR2、TLR4蛋白及mRNA表达降低(P<0.05,P<0.01)。结论维生素K_2抑制细胞钙化的作用可能与TLR2和TLR4表达的下调有关。     

PI3K/AKt/eNOS信号通路在硫化氢抑制ET-1诱导的心肌肥大中的作用

目的观察磷脂酰肌醇-3激酶(PI3K)-蛋白质丝氨酸/苏氨酸激酶(AKt)-内皮型一氧化氮合酶(e NOS)信号转导通路在硫化氢(H2S)抑制内皮素-1(endothelin-1,ET-1)诱导心肌肥大过程中的作用。方法体外培养原代心肌细胞,将其随机分为6组,每组4孔,1对照组:加入等体积无血清的DMEM培养基;2肥大(ET-1)组:加入终浓度为10-8 mol/L的ET-1;剩余4组为实验组,各组分别加入不同终浓度的H2S供体-Na HS:310-15 M Na HS组:加入10-15 mol/L Na HS+10-8 mol/l ET-1;410-14 M Na HS组:加入10-14 mol/L Na HS+10-8 mol/L ET-1;510-13 M Na HS组:加入10-13 mol/L Na HS+10-8 mol/L ET-1;610-12 M Na HS组:加入10-12 mol/L Na HS+10-8 mol/L ET-1。上述各组药物分别刺激24 h后测定心肌细胞表面积、细胞总蛋白含量、培养液NO含量,RT-PCR检测心肌细胞心房利钠肽(atrial natriuretic peptide,ANP)、脑钠肽(B-type natriuretic peptide,BNP)、磷脂酰肌醇-3激酶(phosphatidylinositol-3-kinase,PI3K)、蛋白激酶B(protein kinase B,PKB/AKt)、e NOS m RNA水平,Western Blot技术检测总AKt和磷酸化AKt蛋白表达含量。结果肥大(ET-1)组的心肌细胞表面积(1933.80±143.06)和细胞总蛋白含量(367.51±25.9)均高于对照组(787.27±107.66,218.55±21.28,P0.05),ANP及BNP m RNA的表达量也明显增加(P0.05),但PI3K、AKt、e NOS m RNA表达水平,磷酸化AKt程度和NO的释放量(4.60±0.73)低于对照组(8.63±0.30,P0.05),各实验组给予不同浓度Na HS刺激后能够浓度依赖性的抑制这种肥大效应(P0.05),同时上调了PI3K/AKt/e NOS通路各信号分子的表达量(P0.05)。结论 H2S对ET-1诱导的心肌肥大有一定的抑制作用,这种作用可能与激活PI3K-AKt-e NOS信号通路有关。     

睾酮对维生素D3和尼古丁诱导的主动脉血管钙化的影响

目的建立SD大鼠血管钙化模型,并观察睾酮在主动脉血管钙化中的作用。方法将10周龄SD雄性大鼠分为:对照组、钙化组、钙化+低剂量睾酮组和钙化+高剂量睾酮组,每组8只。除对照组外,其余三组采用维生素D3(300 k U/kg一次肌肉注射)和尼古丁(25 mg/kg溶于花生油中早、晚各灌胃1次)诱导大鼠血管钙化模型;低剂量睾酮组注射1 mg/kg外源性睾酮(隔日注射1次),高剂量睾酮组注射2 mg/kg睾酮(隔日注射1次),持续8周后处死。采用ELISA法测定大鼠血清睾酮和骨形态发生蛋白4(BMP-4)含量,采用试剂盒检测血管组织钙离子及碱性磷酸酶(ALP)含量,蛋白免疫印迹分析(Western blot)检测主动脉血管组织BMP-4、骨桥蛋白(OPN)的蛋白表达水平,Von Kossa染色法观察血管钙化情况。结果 (1)成功制备了大鼠血管钙化模型:Von Kossa染色可见钙化组大鼠血管中膜大量黑色颗粒样钙盐沉积,而对照组血管结构完好,未见黑色钙盐沉积物。(2)睾酮对血管钙化的影响:睾酮组钙含量、ALP、BMP-4、OPN水平显著低于钙化组(P0.01),且高剂量睾酮组低于低剂量睾酮组,对照组水平最低; Von Kossa染色可见钙化组血管中膜出现大量黑色颗粒样钙盐沉积,而低剂量睾酮组和高剂量睾酮组均见少量钙盐沉积,对照组无钙盐沉积。结论外源性睾酮能一定程度上减轻维生素D3和尼古丁诱导的大鼠血管钙化。     

吡格列酮通过内质网应激致凋亡途径对大鼠血管平滑肌细胞钙化的影响

目的　探讨吡格列酮通过内质网应激致凋亡途径对大鼠血管平滑肌细胞钙化的影响及机制。方法　利用β-甘油磷酸钠联合丙酮酸钠制备钙化血管平滑肌细胞模型,予不同浓度（10、50、100　μmol/L）吡格咧酮干预。用Von　Kossa　染色、茜素红S染色测定钙含量以及碱性磷酸酶（ALP）活性观察细胞钙化程度。采用流式细胞术及Tunel法检测细胞凋亡率,实时荧光定量PCR及Western　Blot检测各组细胞GRP78、Caspase-12和Runx2的mRNA及蛋白表达。结果　钙化组其钙含量、ALP活性较对照组细胞增多（P<0.05）,而不同浓度吡格列酮呈剂量依赖性地减轻钙化大鼠血管平滑肌细胞的钙含量和ALP活性（P<0.05）;钙化组其细胞凋亡率较对照组明显升高,而不同浓度吡格列酮呈剂量依赖性地减轻钙化大鼠血管平滑肌细胞凋亡率（P<0.05）;钙化组GRP78、Caspase-12和Runx2　的mRNA及蛋白表达明显升高,而不同浓度吡格列酮呈剂量依赖性地下调钙化大鼠血管平滑肌细胞GRP78、Caspase-12和Runx2的mRNA及蛋白表达（P<0.05）。结论　吡咯列酮通过内质网应激致凋亡途径作用可减轻β-磷酸甘油诱导的血管平滑肌细胞钙化,其作用可能与GRP78、Caspase-12及Runx2表达下调有关。     

吡格列酮对糖尿病大鼠血管钙化的影响及机制

目的研究吡格列酮对糖尿病大鼠血管钙化的影响及其可能机制。方法将36只SD雄性大鼠随机平均分为6组:对照组、糖尿病组、钙化组、糖尿病+钙化组、钙化+吡格列酮组、糖尿病+钙化+吡格列酮组;建立大鼠血管钙化模型(维生素D3+华法林)和糖尿病模型(链尿佐菌素);并对血管组织进行Von Kossa染色、钙含量和碱性磷酸酶活性检测,qRT-PCR检测mRNA表达,免疫组织化学法检测骨保护素蛋白表达。结果钙化组血管平滑肌细胞及其间质内有大量黑色颗粒沉积;糖尿病+钙化组较糖尿病组和钙化组血管组织钙含量、碱性磷酸酶活性分别升高3.63倍、1.35倍和3.69倍、1.30倍(P<0.05),骨保护素mRNA含量及其蛋白表达降低(P<0.05);糖尿病+钙化+吡格列酮组较糖尿病+钙化组钙含量、碱性磷酸酶活性分别下调13.70%、18.04%(P<0.05),骨保护素mRNA含量及其蛋白表达升高(P<0.05)。结论吡格列酮可以减轻血管钙化程度并上调骨保护素mRNA含量及蛋白表达,骨保护素可能是抑制血管钙化主要因素之一。     

阿托伐他汀对大鼠主动脉平滑肌细胞钙化的抑制作用

目的研究阿托伐他汀对体外大鼠主动脉平滑肌细胞钙化(VSMC)的作用。方法采用组织块培养法体外培养大鼠主动脉平滑肌细胞。细胞分5组,即正常组(常规细胞培养液)、钙化组(加入10 mmol／Lβ-磷酸甘油、1×10-7mol／L胰岛素及50μg／L维生素C钙化培养基)和阿托伐他汀(1μmol／L、5μmol／L和10μmol／L)组,后者在诱导血管平滑肌细胞钙化之前,分别给予阿托伐他汀1μmol／L、5μmol/L、10μmol／L预处理24 h后,再加入钙化培养基诱导细胞钙化,连续培养14 d。细胞爬片茜素红S染色观察VSMC钙化;比色法测定细胞Ca2+浓度和细胞蛋白质含量,两者之比作为细胞钙沉积含量;比色法测定细胞ALP活力;MTT法检测细胞增殖。结果阿托伐他汀各组钙结节计数减少,细胞钙沉积含量减少,ALP活力和细胞增殖均降低,并呈剂量依赖性。结论阿托伐他汀对大鼠主动脉平滑肌细胞体外钙化有抑制作用。     

生长素抑制大鼠血管钙化及其可能机制

为探讨生长素调节血管钙化的可能机制,用肌肉注射维生素D3和口服尼古丁诱导大鼠血管钙化模型和β-甘油磷酸盐诱导血管平滑肌细胞钙化模型,采用原子吸收分光光度法测定血管和细胞钙含量,磷酸苯二钠法测定碱性磷酸酶活性,45CaCl2摄入测定钙沉积,逆转录-聚合酶链反应测定生长素、骨桥蛋白和内皮素mRNA表达水平,放射免疫分析方法测定血浆生长素和内皮素含量.结果表明,维生素D3和尼古丁明显诱导大鼠血管钙化,β-磷酸甘油可诱导血管平滑肌细胞钙化.采用30和300nmol/kg生长素治疗大鼠均可抑制血管钙化,且高剂量时效应强于低剂量,与钙化组相比较,血管组织钙化指标均下降并且差异有显著性,而骨桥蛋白mRNA的表达明显上调.10-8～10-6mol/L生长素呈浓度依赖性降低血管平滑肌细胞钙化指标,并上调骨桥蛋白mRNA表达.此外生长素明显下调血浆内皮素浓度及血管组织的内皮素表达,且高剂量生长素的效应更强.结果提示,生长素可能部分通过拮抗血浆和血管组织局部的内皮素系统效应而产生抑制血管组织和血管平滑肌细胞钙化的作用.     

左旋氨氯地平对高钙、高磷诱导的体外血管平滑肌细胞钙化的保护作用

目的研究左旋氨氯地平对高钙、高磷诱导的血管平滑肌细胞钙沉积和骨桥蛋白(0PN)表达的影响。方法将人主动脉平滑肌细胞(HASMCs)分为6组:对照组(Pi 1. 4 mmol/L、Ca 2. 0 mmol/L)、高钙组(Ca 2. 8 mmol/L)、高磷组(Pi2. 5 mmol/L)、左旋氨氯地平组(左旋氨氯地平10 mg·kg~(-1)·d~(-1))、高钙+左旋氨氯地平组(Ca 2. 8 mmol/L+左旋氨氯地平10 mg·kg~(-1)·d~(-1))、高磷+左旋氨氯地平组(Pi 2. 5 mmol/L+左旋氨氯地平10 mg·kg~(-1)·d~(-1))。检测各组细胞内钙含量;分别用Real-time PCR和Western印迹方法检测各组细胞内OPN mRNA和蛋白的表达。结果高钙组和高磷组各时间点细胞内钙含量与对照组比较均显著升高(P<0. 05);与高钙组和高磷组相比,加入左旋氨氯地平干预第6天始,细胞内钙含量显著下降(P<0. 05)。高钙组和高磷组在培养第8天时,OPN mRNA和蛋白水平较对照组均明显增高(P<0. 01);加入左旋氨氯地平干预第8天时,OPN mRNA和蛋白水平均较对照组明显下降(P<0. 01)。结论左旋氨氯地平能减少高钙和高磷诱导的血管平滑肌细胞钙含量,同时能降低OPN mRNA和蛋白水平的表达。     

血管紧张素Ⅱ对正常和高血压大鼠主动脉平滑肌细胞腺苷三磷酸酶的影响

目的 探讨血管紧张素Ⅱ对正常血压Wistar-Kyoto大鼠和自发性高血压大鼠胸主动脉平滑肌细胞膜腺苷三磷酸酶(Ca2+-ATPase和Na+,K+-ATPase)活性及基因表达的影响.方法 组织块种植法培养14周龄Wistar-Kyoto大鼠和自发性高血压大鼠胸主动脉平滑肌细胞,分别加入含有1×10-9、1×10-8和1×10-7 mol/L血管紧张素Ⅱ培养液,共同孵育6 h、12 h和24 h.采用生化酶学方法和逆转录聚合酶链反应技术,检测主动脉平滑肌细胞膜Ca2+-ATPase、Na+,K+-ATPase活性及其mRNA表达水平.结果 低、中浓度血管紧张素Ⅱ(1×10-9和1×10-8 mol/L ) 增加Wistar-Kyoto大鼠 Ca2+-ATPase活性(P<0.05~P<0.01),与干预时间呈正相关(r=0.340, 0.725),24 h达最大值,且上调质膜Ca2+-ATPase 亚型1 mRNA表达 (P<0.05~P<0.01);高浓度 (1×10-7mol/L ) 血管紧张素Ⅱ抑制Ca2+-ATPas活性(P<0.05),与干预时间呈负相关(r=-0.348 ),其24 h效应最强,并下调质膜Ca2+-ATPase 亚型1 mRNA表达 (P<0.05).3种浓度血管紧张素Ⅱ均抑制自发性高血压大鼠 Ca2+-ATPase活性(P<0.05~P<0.01),与干预时间呈负相关 (r=-0.346,-0.493,-0.759),24 h抑制最强,并下调质膜Ca2+-ATPase 亚型1 mRNA表达 (P<0.05~ P<0.01).3种浓度(1×10-9、1×10-8和1×10-7 mol/L )血管紧张素Ⅱ依次在24 h、12 h、6 h显著增加Wistar-Kyoto大鼠Na+,K+-ATPase 活性 (P<0.05~P<0.01),且剂量依赖性增加24 h Na+,K+-ATPase活性及上调α1亚单位mRNA 表达 (P<0.05~P<0.01),与干预时间呈正相关(r=0.425,0.645,0.767 ).低、中浓度血管紧张素Ⅱ对自发性高血压大鼠Na+,K+-ATPase活性及α1亚单位mRNA 表达均无影响 (均P>0.05);高浓度血管紧张素Ⅱ则抑制Na+,K+-ATPase活性(P<0.01),与干预时间呈负相关(r=-0.589),24 h达最大效应,且下调α1亚单位mRNA 表达(P<0.05).结论 血管紧张素Ⅱ对正常血压大鼠主动脉平滑肌细胞膜Ca2+-ATPase活性及质膜Ca2+-ATPase 亚型1 mRNA表达有双向作用,并呈剂量依赖性激活Na+,K+-ATPase活性及α1亚单位mRNA表达;抑制高血压大鼠主动脉平滑肌细胞膜Ca2+-ATPase、Na+,K+-ATPase活性及Ca2+-ATPase亚型1、α1亚单位 mRNA表达.     

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.     

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.     

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.     

Morphological and immunocytochemical heterogeneity of cultured pinealocytes from one-week-and two-month-old rats: Planimetric and densitometric investigations

Abstract: In vitro preparations of rat pinealocytes are widely used for biochemical analyses of signal transduction processes. This paper deals with morphological and immunocytochemical features of such preparations. Special attention was paid to the problems of whether pinealocytes represent a heterogeneous cell population and how such heterogeneity may develop during ontogeny. The investigations were performed with cells which were obtained from the pineal organ of one-week-and two-month-old rats, attached to synthetic peptide-coated coverslips or tissue culture chamber slides, and maintained under in vitro conditions overnight. The attached cells were then fixed with paraformaldehyde. These preparations yielded monolayers of spherical cells of different sizes; most cells were isolated, but some of them were aggregated and formed small clusters. On the average, the cells from the one-week-old animals were smaller than the cells from the two-month-old animals. Immunocytochemical demonstration of S-antigen, a pinealocyte-specific marker, showed that the majority of the cells from two-month-old animals were intensely or moderately labelled. Pinealocytes from one-week-old animals were less S-antigen immunoreactive. Only very few cells (less than 1% displayed glial fibrillary acidic protein (GFAP)-immunoreactivity. Planimetric investigations of the cell size and semiquantitative densitometric investigations of the intensity of the S-antigen immunoreaction revealed that (i) pinealocytes kept in vitro form a heterogeneous cell population, and that (ii) this heterogeneity increases during postnatal development from one-week-old to two-month-old animals. Two groups of pinealocytes can be distinguished based on their developmental fate: pinealocytes of one group grow dramatically, but show only a moderate increase in S-antigen immunoreactivity, and pinealocytes of the other group retain their size, but display a distinct increment in S-antigen immunoreacti vitv.     

MUTATION FREQUENCY IN NURSES AND PHARMACISTS WORKING WITH CYTOTOXIC DRUGS

Individuals occupationally exposed to cytotoxic drugs may be at risk owing to the effects of these agents on DNA. As an index of DNA damage, in vivo mutations were measured in lymphocytes from 24 oncology nurses or pharmacists and 24 matched controls. Mutation frequency was significantly increased in exposed individuals and appeared to be related to duration of exposure. However, the overall magnitude of the increase was small and its biological significance remains to be determined.