红花黄色素对衰老模型小鼠海马区神经细胞凋亡及Bcl-2和PLA2的影响

目的 探讨红花黄色素（SYP）对神经细胞衰老的影响及其作用机制.方法 采用原子吸收法测定线粒体Ca2＋含量,TUNEL末端标记法检测海马区神经细胞凋亡率,化学比色法测定Mn-SOD和MDA含量.结果 SYP能显著提高SOD活性,降低肝线粒体MDA含量,磷脂酶A2（PLA2）活性随龄增高,SYP使PLA2活性显著降低,线粒体Ca2＋明显升高.衰老模型组细胞凋亡率明显高于对照组,SYP能显著降低细胞凋亡率,提高Bcl-2水平.结论 SYP可显著降低衰老模型线粒体膜PLA2活性,有效维持钙稳态.通过增加Bcl-2的表达有效降低神经细胞凋亡,改善脑细胞功能.     

肉苁蓉多糖对衰老大鼠肝线粒体保护作用的研究

目的观察肉苁蓉多糖对D-半乳糖致衰大鼠肝线粒体氧化损伤的保护作用。方法采用D-半乳糖所致衰老模型大鼠,灌服肉苁蓉多糖6 w,测定肝脏Ca2＋-ATP酶活性、肝线粒体丙二醛（MDA）含量、磷脂酶A2（PLA2）活性、膜流动性及呼吸链复合体Ⅰ＋Ⅲ、Ⅱ＋Ⅲ活性。结果肉苁蓉多糖显著提高衰老模型大鼠肝脏Ca2＋-ATP酶活性、肝线粒体膜流动性及呼吸链复合体Ⅰ＋Ⅲ、Ⅱ＋Ⅲ活性,显著降低肝线粒体MDA含量、PLA2活性。结论肉苁蓉多糖能提高衰老模型大鼠肝线粒体抗氧化能力,改善线粒体能量代谢,具有抗衰老作用。     

马齿苋水提液对D-半乳糖致衰模型小鼠心肌线粒体的保护作用

目的探讨马齿苋水提液对衰老模型小鼠心肌线粒体(Mt)的保护作用.方法采用D-半乳糖(D-gal)衰老模型小鼠,马齿苋水提液灌胃30 d.测定心肌Mt内丙二醛(MDA)含量、心磷脂(CL)相对含量及Ca2 -ATP酶(Ca2 -ATPase)、复合体Ⅰ和复合体Ⅱ Ⅲ活性.结果马齿苋水提液能降低衰老模型组小鼠心肌Mt内MDA含量(P＜0.05),提高CL相对含量及Ca2 -ATP酶、复合体Ⅰ和复合体Ⅱ Ⅲ活性(P＜0.05).结论马齿苋水提液通过抑制心肌Mt磷脂的脂质过氧化和改善呼吸链酶的活性而实现对Mt的保护作用.     

L-精氨酸对糖尿病大鼠肝损伤的保护作用

目的探讨L-精氨酸(L-Arg)对糖尿病大鼠肝脏损伤的保护作用。方法给大鼠腹腔注射四氧嘧啶制备糖尿病模型,随机分为糖尿病组、L-Arg治疗组及正常对照组;用药4周末处死大鼠,检测肝细胞线粒体超氧化物歧化酶(Mn-SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)含量,肝组织细胞一氧化氮合酶(NOS)、Na -K -ATPase、Ca2 -ATPase活性以及NO含量。结果与正常组比较,糖尿病组大鼠肝细胞线粒体Mn-SOD、GSH-Px活性明显降低,MDA含量显著升高,肝组织细胞内NOS、Na -K -ATPase、Ca2 -ATPase活性明显降低;与糖尿病组比较,L-Arg治疗组大鼠肝细胞线粒体Mn-SOD、GSH-Px活性明显升高,且肝组织细胞内NOS、Na -K -ATPase、Ca2 -ATPase活性及NO含量显著升高。结论L-Arg对糖尿病大鼠肝脏损伤具有一定的保护作用。     

锁阳水提液对衰老模型小鼠肝线粒体能量代谢的影响

目的 探讨锁阳水提液对衰老模型小鼠肝细胞线粒体能量代谢的影响.方法 以D-半乳糖(D-gal)建立人工致衰模型,观察锁阳水提液对肝线粒体组织形态、NADH脱氢酶、H+-ATP酶活性的影响及MDA的含量变化.结果 衰老模型组肝线粒体减少,内外膜模糊不清,嵴变形、断裂或消失,线粒体出现肿胀、空泡化等改变,NADH脱氢酶和H+-ATP酶活性均降低,MDA含量升高;锁阳水提液可减轻肝线粒体结构与功能的损伤,使NADH脱氢酶和H+-ATP酶的活性升高(P＜0.05,P＜0.01),降低MDA含量(P＜0.05).结论 锁阳水提液对衰老模型小鼠肝线粒体有保护作用.     

水溶性珍珠钙抗小鼠亚急性衰老的药理作用及其机制

目的　观察水溶性珍珠钙 (WCP)的药理作用 ,并对其机制进行初步研究。方法　以D 半乳糖颈部皮下注射复制小鼠亚急性衰老模型 ,分别给予水溶性珍珠钙 (WCP) 0 .6、1 .0g·kg- 1 ·d- 1 ,连续给药 8w ,动物处理后 ,测定胸腺和子宫重量、RBC及脑蛋白含量 ;GSH、总抗氧化能力 ;脑Ca2 含量、Ca2 Mg2 ATP酶、Na K ATP酶 ;脑、肝、血清NO水平。结果　WCP能有效抑制衰老所致的组织萎缩 ;增加衰老小鼠脑GSH水平 (P <0 .0 1 ) ,但总抗氧化能力下降 (P <0 .0 1 ) ;小剂量WCP能显著降低衰老小鼠脑组织中Ca2 水平 ,大剂量却加重钙超载 (P <0 0 5) ;WCP可明显增强衰老状态下Ca2 Mg2 ATP酶及Na K ATP酶活性 (P <0 .0 1 ) ,增加衰老小鼠脑匀浆NO含量 (P <0 .0 5) ;小剂量组减少肝组织及血清NO含量 (P <0 .0 5 ,P <0 .0 1 )。结论　WCP具有抗衰老作用 ,但并不主要通过抗氧自由基损伤发挥效应 ,而很有可能通过对Ca2 Mg2 ATP酶及Na K ATP酶的保护作用 ,而直接调节胞内Ca2 水平 ,抑制衰老过程中的钙超载 ,并进一步影响体内NO代谢起效。     

吡格列酮对高脂血症大鼠缺血再灌注心肌细胞膜的保护作用

目的观察吡格列酮(pioglitazone,PIO)对高脂血症(hyperlipemia,HL)并发缺血再灌注大鼠干预后的心肌细胞膜组分的保护作用,并探究其可能机制。方法建立大鼠高脂模型后,再施以吡格列酮干预,4周后各组行心肌缺血再灌注。术后低温高速离心法制备心肌细胞膜,检测胆固醇(C)、磷脂(phospholipid,PL)及C/P比值、磷脂酶A2(PLA2)活性及钠钾、镁、钙ATPase活性的变化。结果 14周末,与对照组比较,高脂模型组血清中甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDLC)含量显著升高(P0.05);8周末,高脂模型+吡格列酮组大鼠血清中TG、TC含量较高脂模型组显著降低(P0.01和P0.05)。2高脂模型组心肌细胞膜磷脂含量较对照组显著下降(P0.01),而高脂模型+吡格列酮组比高脂模型组含量升高(P0.05)。3高脂模型组C/P比值分别与对照组、高脂模型+吡格列酮组比较,差异均有显著性(P0.01)。4高脂模型组和高脂模型+吡格列酮组心肌细胞膜PLA2活性比对照组升高(P0.05)。5高脂模型组钠钾ATPase活性较对照组降低(P0.05);高脂模型组镁ATPase活性低于对照组(P0.05),而高脂模型+吡格列酮组镁ATPase活性高于高脂模型组(P0.05)。结论吡格列酮对心肌细胞膜正常的C/P比值、PLA2活性、钠钾/镁ATPase活性均有一定的保护作用。     

L-精氨酸对糖尿病大鼠肝、心肌及膈肌线粒体自由基损伤的保护作用

目的探讨L-精氨酸(L-Arg)对糖尿病大鼠肝脏、心肌及膈肌线粒体自由基损伤的保护作用. 方法给大鼠腹腔注射四氧嘧啶制备糖尿病模型,随机分为糖尿病组、L-Arg治疗组及正常对照组;用药4 w末测定三组大鼠肝脏、心肌及膈肌细胞线粒体中Mn-SOD、GSH-Px活性和MDA含量及膈肌线粒体内GSH含量.结果糖尿病组较正常组,大鼠肝、心肌、膈肌线粒体内GSH-Px活性显著降低(P＜0.01,P＜0.05,P＜0.001),MDA含量显著升高(P＜0.01,P＜0.05,P＜0.01),肝、膈肌线粒体Mn-SOD活性(均P＜0.01)及膈肌线粒体GSH含量(P＜0.05)也明显降低;与模型组比较,L-Arg可显著增加糖尿病大鼠肝、心肌、膈肌线粒体GSH-Px活性(P＜0.05,P＜0.05,P＜0.001)及肝、膈肌线粒体Mn-SOD活性(均P＜0.001),并使膈肌线粒体MDA含量显著降低(P＜0.01),而GSH含量明显升高(P＜0.001). 结论糖尿病大鼠肝、心肌、膈肌线粒体内自由基生成增多;L-Arg可通过提高肝、心肌、膈肌细胞线粒体中自由基清除酶的活性来加速自由基的清除,提高机体的抗氧化能力,从而保护机体功能免受氧化损伤.     

茜草多糖对衰老模型小鼠心肌线粒体酶活性影响的实验研究

目的探讨茜草多糖对衰老小鼠心肌线粒体酶活性的影响。方法通过建立D半乳糖人工致衰小鼠模型,测定心肌线粒体超氧化物歧化酶(SOD),Na+K+ATP酶和Ca2+ATP酶的活性。结果衰老模型组SOD、Na+K+ATP酶和Ca2+ATP酶的活性均明显降低;茜草多糖可升高衰老模型组SOD、Na+K+ATP酶和Ca2+ATP酶活性(P<0.05,P<0.01)。结论茜草多糖对衰老模型小鼠心肌线粒体有保护作用。     

丹参多酚酸盐对过氧化氢所致心肌细胞线粒体损伤保护作用的研究

目的 探索丹参多酚酸盐(SAL)对过氧化氢(H2O2)所致H9c2心肌细胞线粒体的保护作用及其机制。方法 以100μmol/L的H2O2干预对数生长期H9c2细胞4 h建立心肌细胞氧化损伤模型,设H2O2组、SAL(50、100、200 mg/L)组;另取对数生长期H9c2细胞设为正常组。药物干预24 h后,通过激光扫描共聚焦显微镜观察线粒体形态,通过透射电子显微镜观察线粒体超微结构;Jc-1荧光探针法检测膜电位(△ψm),检测膜通透性转换孔(MPTP)开放度;DCFH-DA探针法检测细胞活性氧(ROS)含量, Western blot法检测线粒体动力相关蛋白1(Drp1)、磷酸化Drp1(p-Drp1)、细胞色素C(Cyt C)蛋白;比色法检测Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性及三磷酸腺苷(ATP)含量;原子化学发光法检测钙离子(Ca2+)浓度;硫代巴比妥酸法检测线粒体丙二醛(MDA)含量,黄嘌呤氧化法、钼酸铵法分别检测超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性。结果 (1)五组细胞线粒体平均面积比较,差异有统计学意义(F=52.076, P 0.05)。与H2O2组比较,SAL 100、200μg/mL组H9c2细胞线粒体分裂明显减少,线粒体平均面积升高(P 0.05),与SAL 50μg/mL组比较,SAL 100μg/mL组线粒体平均面积显著增加(P 0.05),与SAL 100μg/mL组比较,SAL200 mg/L组线粒体平均面积显著增加(P 0.05)。(2)与H2O2组比较,SAL 100、200μg/mL组线粒体超微结构病变明显改善。(3)与H2O2组比较,SAL 100、200 mg/L组H9c2细胞ROS含量显著降低(P 0.05);与SAL 100 mg/L组比较,SAL 200 mg/L组ROS含量显著降低(P 0.05)。(4)与H2O2组比较,SAL 100、200 mg/L组H9c2细胞线粒体△ψm显著升高且MPTP开放度显著降低(P 0.05);与SAL 50 mg/L组和SAL 100 mg/L组比较,SAL 200 mg/L组△ψm显著升高且MPTP开放度显著降低(P 0.05)。(5)与H2O2组比较,SAL 100、200 mg/L组H9c2细胞Drp1、p-Drp1、Cyt C表达明显下调(P 0.05),且p-Drp1/Drp1显著降低(P 0.05);与SAL 100 mg/L组比较,SAL 200 mg/L组p-Drp1、Cyt C表达明显下调(P 0.05)。(6)与H2O2组比较,SAL 100、200 mg/L组Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性和ATP含量显著升高且Ca2+浓度显著降低(P 0.05);与SAL 50 mg/L组比较,SAL 100 mg/L组Ca2+-Mg2+-ATP酶活性和ATP含量显著升高(P 0.05),SAL 200 mg/L组Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性和ATP含量显著升高且Ca2+浓度显著降低(P 0.05);与SAL 100 mg/L组比较,SAL 200 mg/L组ATP含量显著升高且Ca2+浓度显著降低(P 0.05)。(7)与H2O2组比较,SAL 100、200 mg/L组MDA含量显著降低而SOD、CAT活性显著升高(P 0.05);与SAL 50 mg/L组比较,SAL 200 mg/L组MDA含量显著降低而SOD、CAT活性显著升高(P 0.05);与SAL 100 mg/L组比较,SAL 200 mg/L组MDA含量显著降低而CAT活性显著升高(P 0.05)。结论SAL对H2O2所致H9c2心肌细胞线粒体结构和功能损伤具有保护作用,其机制可能与提高抗氧化酶活性、抑制Drp1磷酸化和抑制Ca2+超载有关。     

A study of the effect of fish oils on the risk factors of cardiovascular and cerebrovascular diseases]

In this study 22 normotensive (NT) and 12 essential hypertensive (EHT) subjects were included to test the possibility that fish oils might influence the blood pressure, plasma lipids and fibrinogen as well as the erythrocytic membrane lipid composition and pump activity. Each EHT subject was given capsules containing fish oils (6 g/d) for 18 days. At the end of the study, SBP fell (P < 0.05) and plasma fibrinogen level decreased (P < 0.05), while DBP, TG, TC, and HDL-C showed no significant change. The fatty acid composition of erythrocyte phosphatidyl ethanolamine (PE) and phosphatidyl choline (PC) showed the following changes: in PE, C22:6, C20:5 increased (P < 0.05; P < 0.01), CI18:1 decreased (P < 0.01); in PC C22:6, C22:4 increased (P < 0.05; P < 0.01). The activity of Na+, Ca2+ max, CaM-stimulated Ca2+ pumps increased (P < 0.05; P < 0.01; P < 0.01). As compared to NT, EHT subjects had higher C20:4 in both PE (P < 0.05) and PC (P < 0.01) and lower C18:2 in PC. It is also shown in this study that EHT subjects have higher C20:4 in both PE (P < 0.05) and PC (P < 0.01) and lower C18:2 in PC as compared to NT ones.     

Comparative effects of feeding different fats on fatty acid composition of major individual phospholipids of rat hearts

Comparative effects of feeding dietary linoleic (corn oil), oleic (olive oil), alpha-linolenic (soybean oil) and polyunsaturated fatty acids (fish oil) on lipid content and fatty acid composition of major individual phospholipids of rat hearts were examined. Feeding different diets did not result in lipid accumulation in the heart. Total triglyceride, nonesterified fatty acid, cholesteryl ester and phospholipid levels of heart tissue were not affected by the type of dietary fatty acid. However, heart free cholesterol levels decreased in both animals fed the olive and the fish oil diets. The percentage of individual phospholipids, phosphatidylcholine (PC), phosphatidylethanolamine (PE) and cardiolipin (CL) did not modify by changes in the dietary fat composition. Heart tissue from animals fed on olive oil were enriched with 18:1 (n-9 + n-7) fatty acid in all phospholipid fractions. Animals fed corn oil contained higher proportions of 18:2 (n-6) for PC, PE and CL, and the ingestion of the soybean oil diet increased 18:2 (n-6) for PC and CL in the same proportion as the ingestion of the corn oil diet. The levels of 22:6 (n-3) were increased in the fish oil-fed group, accompanied by both a decrease in total (n-6) fatty acids and an increase in total (n-3) fatty acids in the three phospholipid fractions. The 20:5 (n-3) was only detected in these animals. These results show that olive oil is as effective as fish oil in reducing heart cholesterol content and support earlier works suggesting the role of fish oil in preventing cardiovascular disease.     

Alterations in phospholipids in acute ischemic myocardium

Alterations in the phospholipid component of membranes were studied in acute myocardial ischemia with respect to sarcoplasmic reticulum (SR) and mitochondria (Mt) in the canine heart and compared with changes in the phospholipid composition of intact membrane treated with exogenous phospholipases (PLases) A2 and C, in order to examine the mechanism of ischemic degradation. As early as 30 min after coronary ligation, the total phospholipid content of SR and Mt decreased significantly, 16.0% and 5.6%, respectively. The patterns of SR and Mt phospholipids from the ischemic myocardia did not differ on the chromatograms from those of the non-ischemic myocardia, and no significant increases in lysophospholipids were found for up to 3 hrs. Among the components of phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) decreased mainly during ischemia, and depletion of PC exceeded that of PE in SR. PLase C hydrolysed phospholipids yielded no lysophospholipids, compared to the production of a large amount of lysophospholipids by PLase A2. It was concluded that degradation of membrane phospholipids occurs in the early stage of myocardial ischemia mainly in PC and PE, which are the major components of membrane phospholipids. This may be an expression of irreversible changes, and the activation of PLase C was considered to play an important role in their degradation.     

再灌注致大鼠心肌线粒体损伤及益心康胶囊的保护作用

目的　观察再灌注对心肌线粒体的损伤 ,评价中药复方———益心康胶囊 (H30 3)的保护作用。方法　利用离体大鼠全心停灌 /再灌 (I/R)模型 ,测定心肌线粒体结构和功能的变化。结果　I/R可致线粒体结构和功能损伤 ,H30 3预先灌注给药可明显减轻心肌脂质过氧化程度 ,抑制磷脂酶A2 活性 ,抑制线粒体磷脂降解和游离脂肪酸生成 ,改善线粒体膜脂流动性。此外对呼吸功能及Ca2 + ATPase活性也具有明显的保护作用。结论　H30 3对再灌注所致的线粒体的损伤具有明显的保护作用     

The effects of dietary omega-3 polyunsaturated fatty acids on erythrocyte membrane phospholipids, erythrocyte deformability and blood viscosity in healthy volunteers

We have examined, in normal subjects, the effects of a daily dietary supplement of fish oil concentrate ('maxEPA'), providing 3 g of omega-3 fatty acids, on erythrocyte membrane phospholipids, erythrocyte deformability and blood viscosity. After 3 weeks, incorporation of C20:5 omega 3 into erythrocyte phosphatidyl choline (PC) was greater compared to phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS). After 6 weeks, there was no further increase in total erythrocyte C20:5 omega 3, but its distribution amongst phospholipid subclasses had changed. C20:5 omega 3 had increased further in PE and PS, but decreased in PC. Incorporation of C20:5 omega 3 also occurred into PC, PE and PS. omega-3 Fatty acids were incorporated almost entirely at the expense of C18:2 omega 6, but total unsaturation of phospholipids was increased. This is consistent with increased lipid fluidity, which may be an important determinant of erythrocyte deformability. The same dosage of maxEPA also resulted in a significant increase in erythrocyte deformability and a concomitant reduction in whole blood viscosity. Since plasma viscosity and haematocrit were unchanged it seems likely that the effects on blood rheology were mediated by changes in erythrocyte lipid fluidity. Modification of blood rheology by dietary omega-3 fatty acids is of potential value in the treatment of vascular disease.     

Phospholipid binding specificities and idiotype expression of hybridoma derived monoclonal autoantibodies from splenic cells of patients with systemic lupus erythematosus.

OBJECTIVE--To analyse the phospholipid binding specificity, functional characteristics and idiotype expression of human hybridoma derived monoclonal autoantibodies (MAb) derived from the spleens of two patients with active systemic lupus erythematosus (SLE). METHODS--The IgM MAbs binding to phospholipids were generated from spleen cells of two patients (RSP and RT) with active SLE and their specificity of binding to neutral phospholipids (phosphatidyl ethanolamine, phosphatidyl choline, platelet activating factor, sphingomyelin) and negatively charged phospholipids (phosphatidyl glycerol, phosphatidyl serine, phosphatidic acid, phosphatidyl inositol and cardiolipin (CL)) analysed. Binding specificity of cross reactive antibodies (those binding to CL and DNA) was confirmed by fluid phase inhibition assays. Lupus anticoagulant activity and beta 2-glycoprotein-1 (beta 2 GP-1) requirement for the antigen binding of these MAbs were detected using the modified dilute Russell's viper venom test and modified anti-CL enzyme linked immunosorbent assay (ELISA), respectively. Expression of idiotypes (Id) Id RT-84 and Id H3 was analysed using rabbit polyclonal and murine monoclonal anti-idiotype reagents, respectively. RESULTS--Twelve clones from the patient RSP and eight clones from patient RT were reactive with phospholipids. Marked differences in phospholipid binding of these MAbs were noted, varying from truly polyreactive (RT-72 bound to most phospholipids tested) to monospecific (RT-84 bound only to CL). Furthermore, MAbs RT-84, RT-129, and RSP-57 had lupus anticoagulant activity and required beta 2 GP-1 for CL binding. It was found that 75% of phospholipid binding antibodies from RT clones expressed RT-84 Id, but none from RSP clones did so, and that Id H3 was expressed only by the RT-83 antibody. CONCLUSION--These results show that human anti-phospholipid MAbs are heterogeneous with respect to phospholipid binding, functional characteristics, and Id expression.     

Altered plasma membrane phospholipid organization in Plasmodium falciparum-infected human erythrocytes

The intraerythrocytic development of the malaria parasite is accompanied by distinct morphological and biochemical changes in the host cell membrane, yet little is known about development-related alterations in the transbilayer organization of membrane phospholipids in parasitized cells. This question was examined in human red cells infected with Plasmodium falciparum. Normal red cells were infected with strain FCR3 or with clonal derivatives that either produce (K+) or do not produce (K-) knobby protuberances on the infected red cells. Parasitized cells were harvested at various stages of parasite development, and the bilayer orientation of red cell membrane phospholipids was determined chemically using 2,4,6-trinitrobenzene sulphonic acid (TNBS) or enzymatically using bee venom phospholipase A2 (PLA2) and sphingomyelinase C (SMC). We found that parasite development was accompanied by distinct alterations in the red cell membrane transbilayer distribution of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS). Increases in the exoplasmic membrane leaflet exposure of PE and PS were larger in the late-stage parasitized cells than in the early-stage parasitized cells. Similar results were obtained for PE membrane distribution using either chemical (TNBS) or enzymatic (PLA2 plus SMC) methods, although changes in PS distribution were observed only with TNBS. Uninfected cohort cells derived from mixed populations of infected and uninfected cells exhibited normal patterns of membrane phospholipid organization. The observed alterations in P falciparum-infected red cell membrane phospholipid distribution, which is independent of the presence or absence of knobby protuberances, might be associated with the drastic changes in cell membrane permeability and susceptibility to early hemolysis observed in the late stages of parasite development.     

Enhanced phospholipase activity in peripheral blood monocytes from patients with rheumatoid arthritis

Peripheral blood monocytes (PBM) from patients with rheumatoid arthritis (RA) produce greater amounts of prostaglandins (PG) than do control cells. To further explore the reasons for the increased PG production, we assessed the phospholipase activities in these cells. We found that PBM from patients with severe RA expressed greater phospholipase A2 (PLA2) and phospholipase C (PLC) activities than did the control cells. Enhanced PLA2 activities were observed in RA patient cells when phosphatidylcholine (PC) or phosphatidylethanolamine (PE) were used as substrates. Enhanced PLC activities also were seen when PC, PE, and phosphatidylinositol (PI) were used as labeled substrates. Increased PLC activity was observed whether linoleic acid or arachidonic acid was esterified to the 2 position of the phospholipid substrate used. Because all patients with RA were treated with nonsteroidal antiinflammatory drugs, we examined the effects of aspirin ingestion on phospholipase activities. Aspirin had no consistent effect on PLA2 activities but markedly inhibited PLC activities against PC, PI, and PE with arachidonic acid in the R2 position. That aspirin enhanced PLC activities against PC and PI with linoleic acid in the R2 position, suggests that PLC activity may be regulated in part by the R2 fatty acid. Our results indicate that increased phospholipase activities exhibited by PBM from RA patients may help explain the increased PG production by these cells. The increased phospholipase activities in PBM from RA patients do not appear to be due solely to nonsteroidal antiinflammatory drug therapy.     

Distribution of phospholipids, fatty acids, and platelet factor 3 activity among subcellular fractions of human platelets.

As compared with other methods, our recently reported method for subcellular fractionation of human platelets improves the separation of mitochondria, alpha granules, and lysosomal enzyme activities. The relative purity of these fractions has led us to undertake the present study to compare the subcellular distribution of phospholipids, fatty acids, and platelet factor 3 (clot-promoting) activity. Two findings pertaining to distribution of phospholipids were entirely new. (1) In the alpha granule zone, plasmalogen phosphatidyl ethanolamine peaked at the expense of diacyl phosphatidyl ethanolamine. (2) The fatty acid composition of the membrane lysophosphatidyl choline suggested that it may have been formed by the action of platelet phospholipase A2 activity. The fatty acids of the membranes showed a markedly asymmetrical distribution in noncholine versus choline phospholipids. The latter held 94%, 72%, and 85%, respectively, of the total content of 16:0, 18:1, and 18:2 fatty acids, whereas 55% of the 18:0, 72% of 20:4, and 67% of higher polyenoic acids other than 20:4 were esterified to the noncholine group. The most important new information related to clot-promoting activity, which, on the basis of protein content, was highest in the membrane fractions, but on the basis of phospholipid content in the nonmembranous fractions. The discussion centers on possible explanations for this novel finding.     

Sarcoplasmic reticular and mitochondrial calcium transport in cardiac hypertrophy

To evaluate changes in Ca2+ transport activities in the cardiac sarcoplasmic reticulum (microsomes) and mitochondria, cardiac hypertrophy was induced in rabbits by constricting the abdominal aorta. The animals showed a stable non-failing left heart hypertrophy between 16-22 weeks after the operation. ATP-dependent Ca2+ uptake and Ca2+ binding activities were depressed in microsomes from hypertrophied rabbits in comparison with sham-operated controls (P less than 0.05). These changes were seen at different concentrations of free Ca2+ (10(-7) to 10(-4)M) and were accompanied by alterations in the phospholipid content of the microsomal fraction. Mitochondrial Ca2+ transport activities and phospholipid content remained unchanged in the hypertrophied heart. The results of this study identify a specific lesion in the sarcotubular membrane and suggest that the depressed Ca2+ transport activity in the microsomal fraction from the hypertrophied myocardium may be due to changes in its phospholipid composition.