二甲双胍调控PI3K/Akt通路对心肌缺血再灌注模型大鼠心肌细胞自噬的影响研究

摘 要 目的：探讨二甲双胍调控磷脂酰肌醇3 激酶（PI3K）/蛋白激酶B（Akt）通路对心肌缺血再灌注模型大鼠心肌细胞自噬的影响。 方法: 将60只SD大鼠随机分为假手术组、模型组、二甲双胍低（150 mg·kg-1）、中（300 mg·kg-1）、高（500 mg·kg-1）剂量组、自噬激动剂组（雷帕霉素,5 mg·kg-1）,制备心肌缺血再灌注大鼠模型,药物处理组于建模前3 d以不同剂量二甲双胍及雷帕霉素每天灌胃治疗,模型组及假手术对照组采用等体积生理盐水灌胃,持续3 d。造模成功12 h后,处死大鼠,三苯基氯化四氮唑（TTC）染色观察各组大鼠心肌梗死面积,酶联免疫吸附实验（ELISA）试剂盒检测血清中磷酸肌酸同工酶（CK MB）及肌钙蛋白I（cTnI）含量,免疫组织化学检测自噬相关蛋白Beclin 1、LC3、P62阳性细胞比例,蛋白免疫印迹（Western blot）检测自噬相关蛋白Beclin 1、LC3（包括LC3 Ⅰ、LC3 Ⅱ）、P62及PI3K/Akt 通路蛋白p PI3K、PI3K、Akt、p Akt表达情况。 结果: 与假手术组比较,模型组大鼠心肌梗死面积、血清中CK MB、cTnI含量、心肌组织中P62阳性细胞比例、P62、p PI3K、p Akt蛋白表达明显升高,心肌组织中Beclin 1、LC3阳性细胞比例、Beclin 1、LC3 Ⅱ蛋白表达明显降低（P＜0.05）;心肌组织中LC3 Ⅰ、PI3K、Akt蛋白表达差异无统计学意义（P＞0.05）。与模型组比较,各药物处理组大鼠心肌梗死面积、血清中CK MB、cTnI含量、心肌组织中P62阳性细胞比例、P62、p PI3K、p Akt蛋白表达明显降低,心肌组织中Beclin 1、LC3阳性细胞比例、Beclin 1、LC3 Ⅱ蛋白表达明显升高（P＜0.05）,且二甲双胍各组呈剂量依赖性。二甲双胍低、中剂量组与自噬激动剂组比较,以上各指标差异有统计学意义（P＜0.05）。 结论: 二甲双胍通过促进心肌缺血再灌注模型大鼠心肌细胞自噬,发挥心肌保护作用,其机制可能与下调PI3K/Akt通路有关。     

二氮嗪后处理对缺血/再灌注心肌的保护作用及其与PI3K/Akt信号通路的关系

目的研究PI3K/Akt信号通路是否参与二氮嗪后处理减轻大鼠心肌缺血/再灌注(I/R)损伤。方法 60只♂SD大鼠随机分为5组(n=12):假手术组(S组)、I/R组、二氮嗪(D组)、wortmannin组(W组)、二氮嗪+wortmannin组(D+W组)。建立大鼠在体心脏I/R模型,除S组外,其余各组均缺血30 min,再灌注120 min。再灌注前5 min,5组分别依次经股静脉输注0.1%DMSO、0.1%DMSO、二氮嗪7mg.kg-1、wortmannin 15μg.kg-1和二氮嗪7 mg.kg-1,其中D+W组于给予二氮嗪前5 min输注wortmannin 15μg.kg-1。记录缺血前、缺血30 min和再灌注120 min时心率(HR)、左室发展压(LVDP)、左室舒张末压(LVEDP);再灌注末,2,3,5-氯化三苯基四氮唑(TTC)染色法检测心肌梗死面积、TUNEL染色法检测心肌细胞凋亡率、Western blot分析p-Akt表达水平。结果各组缺血前心功能指标HR、LVDP、LVEDP无差异(P>0.05)。再灌注120 min后,与I/R组相比,D组和D+W组LVDP明显升高、LVEDP明显降低(P<0.01或<0.05),梗死面积与凋亡率降低(P<0.01或0.05),D组p-Akt表达水平升高(P<0.01);与D组比,D+W组LVDP降低(P<0.05),梗死面积与凋亡率增高(P<0.05),p-Akt表达水平降低(P<0.01)。结论二氮嗪后处理部分通过激活PI3K/Akt信号通路减轻大鼠在体心肌I/R损伤。     

缬沙坦对颈动脉粥样硬化大鼠AT1R/PI3K/Akt/mTOR通路及血管内皮细胞自噬的影响

目的探讨缬沙坦对颈动脉粥样硬化大鼠血管紧张素Ⅱ 1型受体(AT1R)/磷脂酰肌醇3激酶(PI3K)/蛋白激酶B(Akt)/哺乳动物雷帕霉素靶蛋白(mTOR)通路及血管内皮细胞自噬的影响。方法采用高脂饲料饲喂结合颈动脉球囊损伤法制备颈动脉粥样硬化大鼠模型,随机分为模型组(生理盐水),缬沙坦低、中、高(10、20、30 mg/kg)剂量组和阳性对照组(阿托伐他汀,2.5 mg/kg),另取假手术大鼠作为对照组(生理盐水),每组15只,均每天ig给药1次,连续4周,给药体积10 mL/kg。末次给药结束24 h后,全自动生化分析仪检测各组大鼠血脂水平,包括总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C);酶联免疫吸附(ELISA)法检测各组大鼠颈动脉血清中白细胞介素6(IL-6)、白细胞介素1β(IL-1β)和肿瘤坏死因子α(TNF-α)水平;苏木精-伊红(HE)染色观察各组大鼠颈动脉内皮组织病理学变化;单丹磺酰尸胺(MDC)染色法检测各组大鼠颈动脉内皮细胞自噬率;蛋白免疫印迹(Western blotting)法检测各组大鼠自噬标记蛋白LC3-Ⅱ、Beclin 1和通路蛋白AT1R表达水平及PI3K、Akt、mTOR磷酸化水平。结果与对照组相比,模型组大鼠颈动脉组织内皮细胞排列紊乱,内皮破损,大量炎性因子浸润,TC、TG、LDL-C、IL-1β、TNF-α、IL-6水平及AT1R蛋白表达和PI3K、Akt、mTOR磷酸化水平显著升高(P0.05),HDL-C水平、细胞自噬率、LC3-Ⅱ和Beclin 1蛋白表达水平显著降低(P0.05);与模型组相比,缬沙坦低、中、高剂量组大鼠颈动脉组织中内膜逐渐平滑,炎性因子浸润依次减少,TC、TG、LDL-C、IL-1β、TNF-α、IL-6水平及AT1R蛋白表达和PI3K、Akt、mTOR磷酸化水平依次降低(P0.05),HDL水平、细胞自噬率、LC3-Ⅱ和Beclin 1蛋白表达水平显著升高(P0.05);缬沙坦高剂量组与阳性对照组大鼠各项指标差异无统计学意义。结论缬沙坦可能通过下调AT1R/PI3K/AKT/mTOR信号通路,提高LC3-Ⅱ和Beclin 1自噬相关蛋白表达水平,促进颈动脉粥样硬化大鼠血管内皮细胞自噬,减轻炎症反应。     

补阳还五汤通过PI3K/AKT通路调控自噬抗大鼠脑缺血/再灌注损伤的作用

目的 探究补阳还五汤通过PI3K/AKT通路调控自噬抗大鼠脑缺血/再灌注损伤的作用。方法 大鼠随机分为5组(n=10):假手术组(Sham)、模型组(Model)、补阳还五汤组(BYHWD)、PI3K抑制剂组(LY294002)与溶媒剂组(Vehicle)。除Sham组外,其余各组均缺血2 h,再灌注72 h造模处理。Zea Longa评分评估神经缺损、TTC检测脑梗死体积、HE观察脑部缺血半暗带（ischemic penumbra,IP）损伤、免疫荧光检测LC3B、Western blot检测PI3K/AKT通路与自噬标志蛋白。结果 BYHWD组与Model组相比,大鼠神经功能评分降低、脑梗死体积减小、脑部IP病理损伤减轻,PI3K与p-AKT/AKT表达增加,LC3Ⅱ/Ⅰ降低,p62升高（P<0.05）;BYHWD的调控作用被LY294002减弱（P<0.05）。结论 补阳还五汤通过激活PI3K/AKT通路抑制细胞自噬,从而减轻大鼠脑缺血/再灌注损伤。     

PI3K/Akt信号通路在外源性硫化氢后处理大鼠离体心肌中的作用

目的探讨PI3K/Akt信号通路是否参与硫化氢后处理减轻离体大鼠心肌缺血/再灌注损伤。方法 70只♂Sprague Dawley(SD)大鼠随机分为5组(n=14):缺血/再灌注组(I/R组),硫化氢后处理组(N组),溶媒组(D组),LY294002组(L组),硫化氢后处理+LY294002组(N+L组)。采用离体心脏Langendorff灌注模型,平衡灌注20min后停灌40min复灌60min。记录平衡末及灌注结束时的左室舒张末期压(LVEDP)、左室发展压(LVDP)、左室内压上升最大速率(+dp/dt)、左室内压下降最大速率(-dp/dt)、心率(HR)、冠脉血流量(CF);灌注结束时,TTC法染色心肌切片并计算心肌梗死面积百分比,TUNEL法检测心肌细胞凋亡计算凋亡指数(AI),Western blot半定量p-Akt和总的Akt表达水平。结果平衡灌注末各组间心功能指标(基础值)差异未见统计学意义(P>0.05)。灌注结束时,与I/R组比较,N组可改善再灌注损伤心功能的各项指标(P<0.05),使心肌梗死面积缩小和凋亡指数降低(P<0.05),p-Akt表达水平升高(P<0.05)。LY294002逆转了硫化氢后处理的心功能指标、心肌梗死面积、凋亡指数及p-Akt表达水平(P<0.05),使L组和N+L组p-Akt蛋白表达明显低于N组(P<0.05)。结论外源性硫化氢后处理通过PI3K/Akt信号通路减轻离体大鼠心肌缺血/再灌注损伤。     

阿魏酸通过磷酸肌醇 3激酶 /丝氨酸 /苏氨酸蛋白激酶途径保护大鼠免受心肌缺血 /再灌注损伤

目的研究阿魏酸对大鼠心肌缺血 /再灌注(I/R)损伤的保护作用及其可能的机制。方法将雄性 SD大鼠采用随机数字表法分为四组( n=12):假手术组( Sham组), I/R模型组( I/R组);阿魏酸 +I/R组( Fer+I/R组);阿魏酸 +蛋白激酶抑制剂(LY294002)+I/R组( Fer+LY+I/R)。通过结扎左冠状动脉前降支 30 min,然后再灌注 2h,建立 I/R损伤大鼠模型。通过苏木精 -伊红( HE)染色分析大鼠的左心室病理学变化,结合透射电子显微镜观察其超微结构;通过 TUNEL/DAPI双重染色检测大鼠心肌细胞凋亡率。通过蛋白质印迹法( Western blotting)检测 PI3K/Akt信号通路关键调控因子的蛋白表达水平［包括 PI3K、p-Akt(Ser 473)、 Akt、eNOS、p-eNOS(Ser1177)和 p-mTOR(Ser2448)］以及血清超氧化物歧化酶( SOD)、丙二醛( MDA)、肿瘤坏死因子-α(TNF-α)、白细胞介素 6(IL-6)和 IL-1β水平。结果 HE染色,结果显示,相较于假手术组, I/R组大鼠心肌中表现出明显的炎性细胞浸润、细胞膜损伤、细胞坏死和水肿;而 Fer+I/R组大鼠表现心肌细胞坏死、炎性细胞浸润,细胞水肿均明显低于 I/R组,并且心肌纤维结构清晰完整。 TUNEL/DAPI双重染色结果显示, Fer+I/R组大鼠［(18.73±1.01)%］心肌细胞凋亡率明显低于 I/R组［(55.45±1.14)%］(P<0.001)。 Western blotting检测结果表明,与 I/R组相比, Fer+I/R组大鼠 Cleaved caspase-3蛋白表达水平显著降低( P<0.05)PI3K、p-Akt、Akt、p-eNOS(Ser1177)和 p-mTOR(Ser2448)蛋白表达明显上调( P<0.05)。相较于 I/R组,阿魏酸显著抑制 MDA5、T,NF-α、IL-6和 IL-1β的表达( P<0.05)并上调 SOD1蛋白表达水平( P<0.05);而 LY294002处理逆转了阿魏酸在 I/R模型大鼠中对上述细胞因子的调控作用。结论阿,魏酸通过激活 PI3K/Akt信号通路抑制心肌细胞凋亡,减轻炎症反应和氧化应激水平,保护大鼠免受缺血 /再灌注诱导的心肌损伤。     

2型糖尿病大鼠心肌PI3K/Akt/mTOR信号通路的改变及Sirt1的调控机制研究

目的检测Sirt1及PI3K/Akt/mTOR信号通路相关蛋白在糖尿病大鼠心肌及高糖培养的H9C2细胞中的表达变化,明确其在糖尿病心肌病发生发展中的作用。方法高脂饮食联合链脲佐菌素建立2型糖尿病大鼠模型,实验将大鼠分为糖尿病2周、4周、8周模型组和对照组,超声心动图检测大鼠心功能变化,Western blot检测大鼠心肌Sirt1、PI3K、Akt、mTOR、S6K1蛋白表达变化。将H9C2细胞分为正常对照组、DMSO组(78.12 mmol·L~(-1))、高糖(HG)组(33 mmol·L~(-1))、白藜芦醇(Res)组(20μmol·L~(-1))、尼克酰胺(Nam)组(40 mmol·L~(-1)),Western blot及qRT-PCR研究心肌细胞Sirt1、PI3K、Akt、mTOR、S6K1相关蛋白基因转录及表达,研究Sirt1对该信号通路的调控机制。结果在动物实验中,与2周DM大鼠比较,8周DM大鼠心肌Sirt1蛋白表达明显增加。2周模型组大鼠相对于正常对照组心肌PI3K、Akt、mTOR、S6K1表达明显增加,且S6K1表达4周模型组比2周模型组增加更明显,但8周表达降低。在高糖培养的H9C2细胞中,与对照组相比,高糖组Sirt1,PI3K,Akt,mTOR和S6K1表达明显增高。Nam处理组Sirt1表达明显降低,PI3K,Akt,mTOR和S6K1表达增高。Res处理组Sirt1表达明显增高,而PI3K,Akt,mTOR和S6K1表达降低。结论 Sirt1通过负调控PI3K/Akt/mTOR信号通路参与糖尿病心肌损伤,参与早期糖尿病心肌病的发生发展。     

小红参乙酸乙酯提取物调控PI3K/AKT/GSK3-β通路对心肌缺血再灌注损伤大鼠雌激素的影响

目的 研究小红参乙酸乙酯提取物通过调控磷脂酰肌醇3-激酶(phosphatidylinositol-3-OH kinase, PI3K)/蛋白激酶B(protein kinase B,Akt)/糖原合成酶激酶3-β(glycogen synthase kinase 3-β,GSK3-β)通路对心肌缺血再灌注损伤大鼠雌激素的影响。方法 选取SPF级SD雌性大鼠50只,空白组10只,建模中死亡10只,随机分为模型组、低剂量组、高剂量组,每组10只。对照组不做任何处理,模型组、低剂量组、高剂量组进行心肌缺血再灌注损伤模型建模,建模成功后模型组不做任何处理,低剂量组、高剂量组分别给予小红参乙酸乙酯提取物灌胃,其剂量分别为56.7 mg/kg、280 mg/kg。观察大鼠心肌损伤[肌钙蛋白I(CTnI)、肌酸激酶同工酶(CK-MB)]、氧化应激[丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)]、一氧化氮(NO)、内皮-氧化氮合酶(eNOS)含量、性激素、PI3K/AKT/GSK3-β信号通路表达量情况。结果 与空白组比较,模型组、低剂量组、高剂量组cTnI、CK-...     

灯盏花素通过激活线粒体自噬途径减轻糖尿病大鼠心肌缺血再灌注损伤

目的探讨灯盏花素对糖尿病大鼠心肌缺血再灌注损伤(MIRI)及线粒体自噬途径的影响。方法采用高糖高脂饮食联合链脲佐菌素制备糖尿病模型,糖尿病模型成功后再制备MIRI模型,具体分组为对照组(不做任何处理)、模型组(糖尿病+MIRI)、假手术组(糖尿病),均ip等体积生理盐水;灯盏花素低、高剂量组(糖尿病+MIRI),分别ip 100、200mg/kg灯盏花素,每组各10只。连续给药14d后,全自动血生化仪检测各组大鼠血清总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)水平变化,ELISA法检测各组大鼠血清中炎性因子白细胞介素-1β(IL-1β)、IL-6、肿瘤坏死因子α(TNF-α)含量,采用超声检测各组大鼠心脏功能变化,HE染色观察各组大鼠心肌组织病理变化,Westernblotting检测各组大鼠心肌组织微管相关蛋白轻链3(LC3)、Beclin1、哺乳动物雷帕霉素靶蛋白(m TOR)、磷酸肌醇3-激酶(PI3K)、p-PI3K、蛋白激酶B(Akt)和p-Akt蛋白表达情况。结果与对照组相比,假手术组、模型组大鼠心肌细胞破碎、坏死,细胞排列不规则,心肌纤维断裂,伴有炎性细胞浸润,大鼠FBG、血清TC、TG、LDL-C水平、心率(HR)、左心室舒张末压(LVEDP),心肌组织LC3-Ⅱ/LC3-Ⅰ、Beclin1蛋白表达及血清IL-1β、IL-6、TNF-α水平显著升高(P<0.05),血清HDL-C水平、左心室收缩压(LVSP)、平均动脉压(MAP)和左室射血分数(LVEF)及心肌组织m TOR、p-PI3K/PI3K、p-Akt/Akt蛋白表达显著降低(P<0.05);与模型组相比,灯盏花素低、高剂量组大鼠损伤心肌细胞减少,细胞形态逐渐恢复正常,血清TC、TG、LDL-C水平、HR、LVEDP及心肌组织LC3-Ⅱ/LC3-Ⅰ、Beclin1蛋白表达及血清IL-1β、IL-6、TNF-α水平依次降低(P<0.05),血清HDL-C水平、LVSP、MAP、LVEF及心肌组织mTOR、p-PI3K/PI3K、p-Akt/Akt蛋白表达依次升高(P<0.05)。结论灯盏花素可保护糖尿病MIRI大鼠心肌组织,减轻组织自噬及炎症水平,可能是通过激活线粒体自噬PI3K/Akt/mTOR通路实现的。     

九龙藤总黄酮调控自噬对抗心肌缺血/再灌注损伤的实验研究

目的研究九龙藤总黄酮(Bauhinia championii flavones,BCF)调控自噬抗心肌缺血/再灌注损伤的作用。方法120只SD大鼠随机分为假手术组、模型组、BCF高剂量组、BCF低剂量组、自噬抑制剂(3-MA)组(n=8),采用左冠状动脉前降支结扎法制备大鼠心肌缺血/再灌注模型,以紫外分光光度法检测缺血30min、缺血/再灌注1 h及3 h时肌酸激酶同工酶(CK-MB)、诱导型一氧化氮合酶(i NOS)、总抗氧化力(T-AOC)的含量;以Western blot法检测心肌微管相关蛋白轻链3蛋白-Ⅱ(LC3-Ⅱ)、Beclin-1、雷帕霉素靶蛋白(mammalian target of rapamycin,m TOR)的表达。结果与模型组相比,BCF能剂量依赖性提高心肌缺血/再灌注不同时段的T-AOC,降低CK-MB及i NOS含量,下调LC3-Ⅱ、Beclin-1蛋白表达,上调m TOR蛋白表达(P<0.05或P<0.01);与3-MA组相比,BCF能够降低i NOS及CK-MB,提高TAOC水平,缺血期上调LC3-Ⅱ、Beclin-1蛋白表达,再灌注期下调LC3-Ⅱ、Beclin-1蛋白表达,缺血/再灌注期均下调m TOR蛋白表达(P<0.05)。结论自噬在心肌缺血期即发生,并随着缺血/再灌注时间延长而进一步加强;BCF预处理可促进缺血期自噬发生及抑制再灌注时自噬过表达,从而减轻心肌缺血/再灌注损伤。     

Cerebral metabolism of [3H]-p-chloroamphetamine

The time-dependent metabolism of intraventricularly administered $\text{[}{}^3\text{H}\text{]-p-}\text{chloroamphetamine}$ was followed. The parent compound and its metabolites were recovered by high pressure liquid chromatography and characterized by high pressure liquid chromatography, thin-layer chromatography, and gas chromatography-mass spectrometry. By 4 hr after injection, two major toluene-soluble metabolites were present in brain. Their biological half-lives were different from the parent compound. On the basis of their analyses, one of the metabolites is p-chloronorephedrine, the other (P₃) is as yet unidentified. Pretreatment with Lilly 110140 prevented or markedly reduced the synthesis of both p-chloronorephedrine and P₃. Iprindole prevented the synthesis of p-chloronorephedrine. The P₃ appeared first in the brain then in the liver, suggesting that both of these organs can metabolize p-chloroamphetamine to this compound. The metabolites were recovered primarily from the nuclear and microsomal fractions following subcellular fractionation of the brain, with small quantities present in the synaptosomal fraction. The level of metabolites was higher in the brainstem than in the neocortex. Glutathione, administered simultaneously with p-chloroamphetamine either intraventricularly or intraperitoneally failed to alter the toxicity of p-chloroamphetamine.     

Clevudine University of Georgia/Abbott/Bukwang/Triangle/Yale University

The pyrimidine analog, clevudine (L-FMAU: 2'-fluoro-5-methyl-beta-L-arabinofuranosyluridine) is a potent antihepatitis B virus (HBV) and anti-Epstein-Barr virus (EBV) agent, discovered by researchers at the University of Georgia, in collaboration with Yale University and Bukwang. Bukwang transferred its technology to Triangle Pharmaceuticals in 1998 together with a license to develop clevudine worldwide except Korea [279649], [281942]. In June 1999, Triangle and Abbott Laboratories entered into a strategic alliance to copromote antiviral products including L-FMAU [326798]. In September 2000, Triangle Pharmaceuticals Inc initiated a 30-day phase I/II evaluation of clevudine in HBV-infected patients [381755]. Clevudine is a much less toxic derivative of the toxic agent P-D-FMAU. The mechanism of action of clevudine is not yet clear, but the agent induces a rapid decrease in HBV nucleic acid as doses increase from 0.3 to 10 mg/kg [319145]. It is believed that the target for clevudine lies in the viral replication mechanism. Clevudine is phosphorylated to the triphosphate form intracellularly. This is removed slowly from the cells, thus exerting a sustained inhibitory antiviral activity [178173], [320720], [320721].     

Spotlight from the American Society for Preventive Cardiology on Key Features of the 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guidelines on the Management of Blood Cholesterol

The 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol retains focus on recommendations for statin treatment in the original four statin-eligible groups [those with atherosclerotic cardiovascular disease (ASCVD), diabetes, low-density lipoprotein cholesterol (LDL-C) ≥ 190 mg/dL, and higher risk primary prevention] without the use of treatment initiation or target LDL-C levels from the earlier 2013 American College of Cardiology/American Heart Association (ACC/AHA) guideline, but has several new features. First, patients with primary prevention are divided into those who are at low (< 5%), borderline (5% to < 7.5%), intermediate (7.5% to < 20%), and high (≥ 20%) risk based on the ASCVD risk estimator. Moreover, the new guideline goes further to consider a wider range of factors [now called “risk enhancers”—premature family history of ASCVD, persistently high LDL-C, chronic kidney disease (CKD), metabolic syndrome, conditions specific to women, inflammatory diseases, and high-risk ethnicities] that can be used to better inform the treatment decision. Moreover, more detailed recommendations on how the results of coronary calcium scanning can be used to inform the treatment decision are provided, including how it may be used to “de-risk” certain patients for delaying or avoiding the use of statin therapy. There are also specific sections for cholesterol management in other patient subgroups including women, children, certain ethnic groups, those with CKD, chronic inflammatory disorders and HIV, as well as discussion on the management of hypertriglyceridemia. Importantly, for persons with known ASCVD, a distinction is made for those who are at “very high risk” based on having had two major ASCVD events or one major event and two or more other high risk conditions, such as diabetes or other major risk factors, or bypass surgery or percutaneous intervention. Finally, the concept of a threshold LDL-C for initiating a non-statin therapy (after considering highest tolerated statin dosage) is provided, with ezetimibe recommended as the key non-statin to be added if the LDL-C still remains ≥ 70 mg/dL for all ASCVD patients, and in those who are at “very high risk”, further consideration for using a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor. While the new guideline does have greater detail (and arguably, complexity), the refinements provide a strategy for guiding the clinician to target both statin and non-statin therapy to those most likely to derive benefit.     

Pitavastatin Nissan/Kowa Yakuhin/Novartis/Sankyo

Pitavastatin (nisvastatin) is an HMG CoA reductase inhibitor being developed jointly by Nissan, Kowa Kogyo, Novartis and Sankyo for the potential treatment of atherosclerosis and hyperlipidemia.     

Amlodipine/Valsartan/Hydrochlorothiazide

Amlodipine/valsartan/hydrochlorothiazide (HCTZ) is a fixed-dose combination of the well established antihypertensive agents amlodipine (a calcium channel antagonist), valsartan (an angiotensin II receptor antagonist), and HCTZ (a thiazide diuretic). In patients with moderate or severe hypertension, triple combination therapy with amlodipine + valsartan + HCTZ produced significantly greater reductions from baseline in mean sitting systolic and diastolic BP (msSBP and msDBP) than either valsartan + HCTZ, amlodipine + HCTZ, or amlodipine + valsartan in a large, 8-week, randomized, double-blind, multinational, phase III trial. Furthermore, the proportion of patients achieving overall BP control at endpoint was significantly greater with the triple combination regimen than with any of the dual regimens, with significantly more triple combination recipients achieving msSBP and msDBP control at each assessment throughout the trial. Subgroup analyses of this study suggested that amlodipine + valsartan + HCTZ was generally more effective in reducing BP and providing overall BP control than the dual combination therapies, irrespective of age, race, gender, ethnicity, or hypertension severity. Several smaller studies provide data that support the efficacy of amlodipine + valsartan + HCTZ in patients whose BP is inadequately controlled with amlodipine + valsartan, amlodipine + HCTZ, or valsartan + HCTZ dual combination therapy. Treatment with amlodipine + valsartan + HCTZ for up to 8 weeks was generally well tolerated in the large, phase III trial, with most adverse events being transient and of mild to moderate severity.     

N-Nitroso-N-Methyldodecylamine and N-Nitroso-N-Methyltetradecylamine in household dishwashing liquids

Eleven household dishwashing liquids and four household surface cleaners were analysed for N-nitroso-N-methyldodecylamine and N-nitroso-N-methyltetradecylamine by gas chromatography with detection using a Thermal Energy Analyzer. Both nitrosamines were found in three of the dishwashing detergents and one of the surface cleaners. [1-¹⁴C]-N-Nitroso-N-methyldodecylamine was used to determine recoveries, which were between 65 and 88%. Levels of N-nitroso-N-methyldodecylamine ranged from 112 to 661 ppb and those of N-nitroso-N-methyltetradecylamine from 46 to 151 ppb. A simple method was developed to screen the products for N,N-dimethyldodecylamine-N-oxide, a surfactant ingredient suspected of being the source of these nitrosamines. By application of this method it was established that all of the products formulated with this amine oxide contained these two nitrosamines, whereas in products that did not contain this ingredient, these nitrosamines were not detected.     

PROTON AND POTASSIUM TRANSPORT BY H+/K+-ATPases

1. H⁺/K⁺-ATPases are members of the P-type ATPase multigene family. The prototypical H⁺/K⁺-ATPase is the protein that acidifies gastric luminal contents. The physiological and pharmacological significance of this pump has led to a detailed investigation of its biochemistry and molecular and cell biology. 2. Recently, a number of closely related H⁺/K⁺-ATPase isoforms have been discovered. These isoforms are present in organs other than the stomach, including the colon and kidney, where they contribute to acid—base and potassium homeostasis. The structure, expression and physiological roles of the gastric H⁺/K⁺-ATPase and other isoforms are reviewed.     

INTERACTIONS OF Na+, H2O2 AND THE Na+-Ca2+ EXCHANGER STIMULATE Ca2+ RELEASE IN CK1.4 CELLS

1. The present study aimed to demonstrate that interactions of cations, hydrogen peroxide (H₂O₂) and the Na⁺-Ca²⁺exchanger stimulate Ca²⁺ release and oscillations of cytosolic Ca²⁺ [Ca²⁺]i in non-transfected Chinese Hamster Ovary (CHO) C1 cells and in transfected CHO (CK1.4) cells that contained an expression vector coding the Na⁺-Ca²⁺ exchanger sequence. 2. The [⁴⁵Ca²⁺] uptake assay, fura-2 fluorescence imaging and 2² and 2³ factorial orthogonal statistics provide comparative, direct, efficient, quantitative and transient methods to delineate the effects of such interactions on Ca²⁺ influx, Ca²⁺release and [Ca²⁺]i in C1 and CK1.4 cells. 3. In contrast to the control of either Na⁺-, Ca²⁺- or H₂O₂-free or CI cells, an elevated [⁴⁵Ca²⁺] uptake was induced by Ca²⁺, Na⁺ and H₂O₂ individually and in combination, intracellular Ca²⁺ release was activated by H₂O₂ and by combinations of either H₂O₂ and Na⁺, H₂O₂ and the Na⁺-Ca²⁺ exchanger, Na⁺ and the Na⁺-Ca²⁺ exchanger or by H₂O₂, Na⁺ and the Na⁺-Ca²⁺ exchanger and a rise in [Ca²⁺]i was triggered by H₂O₂, Na⁺ and a combination of Na⁺ and the Na⁺-Ca²⁺exchanger. 4. These results indicate that interactions between H₂O₂, Na⁺ and the Na⁺-Ca²⁺ exchanger stimulate intracellular Ca²⁺mobilization via Ca²⁺-induced Ca²⁺ release mechanisms, ATP-activated G-protein coupled P_2y-purinoceptor-sensitive pathways, Na⁺-Ca²⁺ exchanger-mediated Ca²⁺ influx and cation-π interaction (a strong non-covalent force between the cation and the π face of an aromatic structure in the transmembrane protein). 5. The present findings provide important clues for understanding Ca²⁺ signal transduction mechanisms from the plasma membrane to the endoplasmic reticulum.     

EFFECTS OF THE OPIOID PEPTIDES [MET5]ENKEPHALIN-ARG6-PHE7 AND [MET5]ENKEPHALIN-ARG6-GLY7-LEU8 ON CHOLINERGIC NEUROTRANSMISSION IN THE RABBIT ISOLATED ATRIA

1. The effect of the opioid peptides [Met5]enkephalin-Arg6-Phe7 (MEAP) and [Met5]enkephalin-Arg6-Gly7-Leu8 (MEAGL) were compared with those of [Leu5]enkephalin and [D-Ala2,Met5]enkephalinamide (DAME) on cholinergic neurotransmission in the rabbit isolated atria. 2. Rabbit isolated atria had a resting rate of 190 beats/min. In the presence of the beta-adrenoceptor antagonist propranolol (0.3 mumol/l), atria responded to electrical field stimulation with a cholinergically mediated negative chronotropic response. The opioid peptides had no effect on the resting rate, but inhibited the negative chronotropic response to field stimulation. The IC50 values for inhibiting the cholinergic responses were 1.4 mumol/l for [Leu5]enkephalin (LE), 1.4 mumol/l for MEAP, 1.3 mumol/l for MEAGL and 0.2 mumol/l for DAME. Responses of a similar magnitude to exogenous acetylcholine were unaffected. 3. Thus, MEAP, MEAGL and LE had similar potencies but DAME was about seven times more potent in inhibiting cholinergic neurotransmission in the rabbit isolated atria. The site of inhibition appears to be prejunctional.