过表达miR-150通过PI3K/AKT信号通路调控结直肠癌细胞凋亡的机制研究

目的探讨过表达miR-150通过磷脂酰肌醇-3-羟激酶/丝苏氨酸蛋白激酶(phosphatidylinositol 3-hydroxykinase/seronine kinase,PI3K/AKT)信号通路调控结直肠癌细胞凋亡的机制。方法将体外培养HT-29细胞分为空白对照组(转染空脂质体) NC组(转染mimic)和miR-150(转染miR-150 mimic);采用RT-PCR检测转染后细胞中miR-150 mRNA水平; CCK-8法检测细胞增殖;流式细胞仪检测细胞凋亡; WB法检测Cleaved caspase3、PI3K、p-PI3K、AKT、p-AKT蛋白表达。将对数生长期HT-29分为阴性对照组、miR-150组、LY294002组和LY294002+miR-150组,采用PI3K抑制剂验证LY294002在HT-29细胞凋亡中的作用。结果与空白对照组和NC组相比,miR-150组细胞中miR-150 mRNA水平明显升高(P 0. 05),24 h、48 h、72 h和96h的细胞抑制率明显升高(P 0. 05),细胞凋亡率明显升高(P 0. 05),Bcl-2/Bax、p-PI3K/PI3K和p-Akt/Akt蛋白的表达明显降低(P 0. 05),cleaved Caspase-3蛋白的表达明显升高(P 0. 05);与阴性对照组相比,miR-150组和LY294002组p-Akt/Akt和Bcl-2/Bax蛋白表达均明显降低(P 0. 05),cleaved Caspase-3蛋白表达明显升高(P 0. 05);与miR-150组相比,LY294002+miR-150组p-Akt/Akt和Bcl-2/Bax蛋白表达均明显升高(P 0. 05),cleaved Caspase-3蛋白表达明显降低(P 0. 05)。结论 miR-150过表达可能通过负调控PI3K/AKT信号通路抑制人结直肠癌细胞的增殖,促进其凋亡。     

广藿香酮对脑卒中大鼠的影响及其作用机制

背景广藿香酮(POG)具有抗癌、抗炎、抗菌等多重药理作用,但目前关于其治疗脑卒中的研究报道较少。目的探讨POG对脑卒中大鼠的影响及其作用机制。方法本实验于2018年12月-2019年4月完成。选取7~8周龄SPF级雄性Sprague-Dawley大鼠36只,随机分为空白对照组(未经模型诱导,n=6)、对照组(建模后未经治疗,n=6)、低剂量组(建模24 h后给予POG 5 mg/kg,n=6)、中剂量组(建模24 h后给予POG 15 mg/kg,n=6)、高剂量组(建模24 h后给予POG 45 mg/kg,n=6)和LY294002组(建模24 h后给予0.1%~0.3%二甲亚砜溶解浓度为0.1%,n=6)。比较六组大鼠磷酸化PI3K(p-PI3K)、磷酸化AKT(p-AKT)、磷酸化内皮型一氧化氮合酶(p-eNOS)蛋白相对表达量,血管内皮生长因子(VEGF)、B细胞淋巴瘤2 (Bcl-2)、Bcl-2相关X蛋白(Bax)蛋白及mRNA相对表达量,大脑皮质和外周血中的超氧化物歧化酶(SOD)、丙二醛(MDA)和一氧化氮(NO)水平。结果 (1)高剂量组大鼠p-PI3K、p-AKT、p-eNOS蛋白相对表达量低于对照组,p-AKT和p-eNOS蛋白相对表达量高于LY294002组(P<0.05)。(2)高剂量组大鼠Bcl-2蛋白相对表达量高于对照组,Bax、VEGF蛋白相对表达量低于对照组(P<0.05);高剂量组大鼠Bcl-2、VEGF mRNA相对表达量高于对照组,Bax mRNA相对表达量低于对照组(P<0.05)。(3)高剂量组大鼠大脑皮质和外周血NO、SOD水平高于对照组,大脑皮质和外周血MDA水平低于对照组(P<0.05);高剂量组大鼠大脑皮质和外周血MDA水平高于LY294002组,大脑皮质和外周血SOD水平低于LY294002组(P<0.05)。结论 POG可通过抑制PI3K/AKT-eNOS信号通路及脂质过氧化而减轻脑卒中大鼠脑组织损伤,且无剂量依赖性。     

Matrine inhibits bladder cancer cell growth and invasion in vitro through PI3K/AKT signaling pathway:An experimental study

Objective:To study the inhibitory effect of matrine on bladder cancer cell growth and invasion in vitro through PI3K/AKT signaling pathway. Methods:Human T24 bladder cancer cell lines were cultured and treated with different doses of matrine(0.25 mg/mL,0.5 mg/mL and 1.0 mg/mL) as well as 20 μmol/L PI3K inhibitor LY294002 for 24 h,and the cell proliferation activity,the number of invasive cells as well as the expression of p-PI3K,p-AKT,proliferation genes and invasion genes were determined. Results:Different doses of matrine could decrease the cell viability value,the number of invasive cells as well as the expression of p-PI3K,p-AKT,MMP2 and MMP9,and increase the expression of p16,p21 and p27 in dose-dependent manner; p16,p21 and p27 expression in cells of 20 μmol/L LY29002 group were significantly higher than those of 0 μmol/L LY29002 group while MMP2 and MMP9 expression were significantly lower than those of 0 μmol/L LY29002 group(P0.05). Conclusions:Matrine can inhibit bladder cancer cell proliferation and invasion in vitro and regulate the expression of cell cycle-inhibiting molecules and invasion-related genes through PI3K/AKT signaling pathway.     

通过沉默GOLPH3抑制PI3K/AKT信号通路调节食管癌氧化应激与细胞凋亡的机制研究

目的 分析GOLPH3对食管癌氧化应激与细胞凋亡的影响及其作用机制。方法 利用qRT-PCR和Western blotting实验分析食管癌组织和癌旁组织中GOLPH3 mRNA和蛋白表达水平，培养EC9706细胞，将GOLPH3 siRNA与siRNA NC、pcDNA-GOLPH3与pcDNA-3.1(+)分别转染细胞，利用丙二醛试剂盒测定MDA含量，超氧化物歧化酶试剂盒测定SOD活力，谷胱甘肽过氧化物酶试剂盒测定GSH-Px活力，过氧化氢酶试剂盒测定CAT活力，Western blotting实验分析EC9706细胞内Bax、Bcl-2、PI3K、p-PI3K、AKT和p-AKT蛋白表达，流式细胞仪分析EC9706细胞凋亡率。PI3K/AKT信号通路抑制剂LY294002作用EC9706细胞后，分析细胞氧化应激、细胞活力与细胞凋亡率。结果 食管癌组织中GOLPH3基因与蛋白表达显著上调(P<0.01)。GOLPH3表达下调后，EC9706细胞活力、SOD、CAT、GSH-Px活力、p-PI3K/PI3K比值、p-AKT/AKT比值与Bcl-2表达显著下调，细胞凋亡率、MDA...     

补阳还五汤对脑损伤大鼠脑组织凋亡信号通路的影响

目的探究补阳还五汤对脑出血大鼠脑组织PI3K/AKT信号转导通路的影响及可能机制。方法 SD大鼠随机分为假手术组、模型组、补阳还五汤组、银杏叶片组,其中模型组、补阳还五汤组、银杏叶片组采用Rosenberg法复制脑出血大鼠模型。免疫组化法检测PI3K、AKT、Bcl-2、BAX蛋白的表达,TUNEL法检测细胞凋亡变化,干湿重法检测脑组织水含量,甲酰胺法检测血脑屏障(BBB)通透性。结果与模型组比较,补阳还五汤组、银杏叶片组PI3K、AKT蛋白表达、Bcl-2/BAX值均显著增高(P0.05),脑组织含水量、伊文思蓝含量、细胞凋亡数量显著降低(P0.05)。结论补阳还五汤对脑出血的保护作用机制可能是其不但降低了BBB通透性,而且激活了PI3K/AKT信号通路,介导Bcl-2、BAX蛋白表达变化,调节二者之间的比值。     

姜黄素对脑缺血大鼠脑组织PI3K/AKT信号通路的影响

目的探究姜黄素对脑缺血大鼠脑组织PI3K/Akt信号转导通路的影响及机制。方法 SD大鼠随机分为假手术组、模型组、低剂量姜黄素组、高剂量姜黄素组,每组大鼠18只。其中模型组、低、高剂量姜黄素慢性脑缺血大鼠模型的制备采用将大鼠两侧颈动脉结扎的方法进行,假手术组和模型组分别灌胃给予生理盐水。免疫组化法检测PI3K、AKT、Bcl-2、Bax蛋白的表达,干湿重法检测脑组织水含量,甲酰胺法检测血脑屏障通透性。结果同模型组比较,姜黄素组PI3K、AKT、Bcl-2蛋白表达均明显增高(P<0.05),脑组织含水量、Bax蛋白表达及伊文思蓝含量显著降低(P<0.05),高剂量姜黄素组效果优于低剂量姜黄素组。结论姜黄素对缺血性脑损伤的保护作用可能是其在降低血脑屏障通透性之后,激活了PI3K/AKT信号转导通路,介导Bcl-2蛋白表达增加,Bax蛋白表达降低,通过调节二者比值实现,姜黄素的脑保护效果与剂量相关。     

芒果苷对缺氧缺血性脑损伤大鼠氧化应激反应及神经细胞凋亡的影响

目的研究芒果苷通过PI3K/Akt/mTOR途径对缺氧缺血性脑损伤大鼠的氧化应激反应及神经细胞凋亡的影响。方法将144只SD新生大鼠按随机原则分为6组,空白对照组、模型组、阳性对照组、芒果苷低剂量组、芒果苷中剂量组和芒果苷高剂量组,每组24只。除空白对照组外其他各组复制缺氧缺血性脑损伤大鼠模型,造模后空白对照组和模型组给予等体积的生理盐水,阳性对照组给予尼莫地平[0.4 mg/(kg·d)],芒果苷低、中、高剂量组分别给予芒果苷50、100、200 mg/(kg·d),连续给药4周。检测各组大鼠神经功能损伤评分;干湿重法检测各组大鼠脑组织含水量;HE染色观察大鼠脑组织的病理形态学改变;原位细胞凋亡检测(TUNEL)大鼠脑组织神经元凋亡情况;生化检测法测定脑组织中超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)和总抗氧化能力(T-AOC)活力;采用实时荧光定量PCR(Real-time PCR)测定大鼠脑组织内PI3K/Akt/mTOR mRNA表达;运用蛋白免疫印迹法(Western blot)检测脑组织中Caspase-3、Bcl-2、Bcl-xL、Bad、Bax蛋白含量。结果模型组大鼠的神经损伤评分、脑组织含水量、神经细胞凋亡数、MDA含量、PI3K表达及Caspase-3含量显著高于空白对照组,完整的神经元数量及脑组织中SOD、GSH-Px、T-AOC含量、Akt、mTOR表达及Bcl-2、Bcl-xL、Bad含量显著低于空白对照组(P0.01);各药物组大鼠的神经损伤评分、脑组织含水量、神经细胞凋亡数、MDA含量、PI3K表达及Caspase-3含量显著低于模型组,完整的神经元数量及脑组织中SOD、GSH-Px、T-AOC含量、Akt、mTOR表达及Bcl-2、Bcl-xL、Bad含量显著高于模型组(P0.01)。结论芒果苷通过下调Caspase-3的表达、上调Bcl-2和Bcl-xL的表达,增强PI3K/Akt/mTOR通路的表达来增强神经保护作用,抑制神经细胞凋亡,提高神经细胞存活率。     

补阳还五汤提取物灌胃对脑出血大鼠脑组织中PI3K、AKT、Caspase-3表达的影响

目的 观察补阳还五汤提取物对脑出血大鼠脑组织磷脂酰肌醇3激酶(PI3K)、丝/苏氨酸蛋白激酶(AKT)、半胱氨酸天冬氨酸蛋白水解酶3(Caspase-3)表达的影响,探讨其对脑组织的保护作用机制。方法 将72只SD大鼠随机分为假手术组、模型组、补阳还五汤组、银杏叶片组各18只,后4组采用Rosenberg法建立脑出血大鼠模型后,分别给予生理盐水、补阳还五汤提取物、银杏叶片连续灌胃35 d。用免疫组化法检测PI3K、AKT、Caspase-3蛋白表达,TUNEL法检测脑组织细胞凋亡情况,干湿重法检测脑组织含水量,甲酰胺法检测血-脑脊液屏障通透性。结果 与模型组比较,补阳还五汤组、银杏叶片组PI3K、AKT蛋白表达水平升高,Caspase-3蛋白表达水平降低,脑组织含水量、凋亡细胞数减少,血-脑脊液屏障通透性降低(P均<0.05)。结论 补阳还五汤提取物可能通过激活PI3K/AKT信号通路,降低血-脑脊液屏障通透性来保护脑出血大鼠脑组织。     

水飞蓟素对重症急性胰腺炎大鼠肠道损伤及PI3K/Akt和NF-κB信号通路影响

背景急性胰腺炎是临床十分常见的急腹症,过量的炎症因子释放会损伤肠黏膜,诱导细胞凋亡,加快病程.水飞蓟素有抗氧化、免疫调节、消炎、保护肝脏、抗组织纤维化等功效.但目前尚未见关于水飞蓟素在重症急性胰腺炎肠道损伤中的相关研究.目的研究水飞蓟素对重症急性胰腺炎大鼠肠道损伤及PI3K/Akt和NF-κB信号通路的影响.方法实验分成Control组、重症急性胰腺炎(severe acute pancreatitismodel,SAP)组、Experimental+L组(重症急性胰腺炎模型,给予60mg/kg水飞蓟素治疗)、Experimental+M组(重症急性胰腺炎模型,给予120 mg/kg水飞蓟素治疗)、Experimental+H组(重症急性胰腺炎模型,给予240 mg/kg水飞蓟素治疗)、Glutamine组(1.5 g/kg谷氨酰胺治疗),观察大鼠死亡情况,全自动生化分析仪检测血清中淀粉酶、脂肪酶水平,用ELISA法检测血清中白介素(interleukin, IL)-1β、肿瘤坏死因子(tumor necrosis factor, TNF)-α含量,对大鼠进行胰腺病理评分和回肠病理评分, Western blot检测回肠组织中Bcl-2、Bax、PI3K、p-PI3K、Akt、p-Akt、NF-κBp65蛋白表达, TUNEL法检测回肠组织中细胞凋亡情况.结果SAP组大鼠死亡3只,Control、Experimental+L、Experimental+M、Experimental+H组大鼠分别死亡0只、2只、1只和0只.与Control组相比, SAP组大鼠血清中淀粉酶、脂肪酶以及IL-1β、TNF-α水平升高,胰腺病理评分和回肠病理评分均升高, Bax、p-PI3K/PI3K、p-Akt/Akt、NF-κBp65蛋白水平和细胞凋亡指数均升高, Bcl-2蛋白表达水平降低.与SAP组比较,Experimental+L、Experimental+M、Experimental+H组大鼠血清中淀粉酶、脂肪酶以及IL-1β、TNF-α水平均逐渐降低,胰腺病理评分和回肠病理评分均逐渐降低, Bax、p-PI3K/PI3K、p-Akt/Akt、NF-κBp65蛋白水平和细胞凋亡指数均逐渐降低, Bcl-2蛋白表达水平逐渐升高.与SAP组比较, Glutamine组大鼠血清中淀粉酶、脂肪酶以及IL-1β、TNF-α水平均降低,胰腺病理评分和回肠病理评分均降低, Bax、p-PI3K/PI3K、p-Akt/Akt、NF-κBp65蛋白水平和细胞凋亡指数均降低, Bcl-2蛋白表达水平升高.结论水飞蓟素减轻重症急性胰腺炎大鼠肠道损伤,抑制炎症,减少细胞凋亡,抑制PI3K/Akt和NF-κB信号通路激活.     

PI3K/AKT/GSK3-b信号转导通路在红景天苷保护大鼠心肌缺血再灌注损伤中的作用机制

目的研究磷脂酰肌醇-3激酶/丝氨酸-苏氨酸蛋白激酶/糖原合酶激酶-3b(PI3K/AKT/GSK3-b)信号传导通路在红景天苷保护大鼠心肌缺血再灌注损伤中的作用机制。方法健康雄性清洁级SD大鼠,结扎大鼠左冠状动脉前降支,复制心肌缺血再灌注损伤(I/R)模型,随机分为6组:假手术组(Sham)、心肌缺血-再灌注模型组(I/R)、红景天苷预防组(红景天苷+缺血再灌注,S+I/R)、红景天苷治疗组(缺血再灌注+红景天苷,I/R+S)、红景天苷预防组+P13 K特异性抑制剂LY294002组(S+I/R+LY组)、红景天苷治疗组+P13K特异性抑制剂LY294002组(I/R+S+LY组),每组6只。采用免疫细胞化学法检测细胞内丝氨酸-苏氨酸蛋白激酶(AKT)、AKT磷酸化(p-AKT)、糖原合酶激酶(GSK3-b)、GSK3-b磷酸化(p-GSK3-b)的表达,Western Blot检测细胞内p-AKT、p-GSK3-b蛋白表达。结果免疫细胞化学法和Western Blot结果显示:与I/R组相比,红景天苷预防组、治疗组大鼠心肌组织中AKT、GSK3-b的磷酸化激活程度显著升高(P0.05),红景天苷预防组和治疗组组间AKT、GSK3-b磷酸化状态比较,差异无统计学意义(P0.05),此变化被PI3K特异性抑制剂LY294002部分阻断(P0.05);I/R组与Sham组相比,AKT、GSK3-b磷酸化蛋白表达略增加,两组差异无统计学意义(P0.05)。结论红景天苷对大鼠心肌缺血-再灌注损伤具有显著的保护作用,推测其可能机制主要与激活PI3K/AKT/GSK3-b信号通路等因素有关。     

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.     

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.