Abstract:DNA was extracted from aldehydride fixed human atherosclerotic plaques. By the method of PCR, P53 gene fragments were amplified. Cloning these fragments into SK vector and sequencing them, we found that p53 gene T~(272) changed into C~(272). Immunohistochemistry showed that in plaques,the mutatant protein expressed. These results indicated that p53 gene mutation may be related with cell proliferation of atherosclerosis.

Abstract:When antisense myc oligodeoxynucleotide (ODNs) (18-mer) were introduced into the medium of the smooth muscle cells (SMCs) of WKY in concentrations ranging from 6 to 12 uM,the 18-met ODNs,in a concentration-related manner,decreased SMCs growth induced by endothelin (10~(-7)mol/L). The inhibitory effect (12umol/L) was about 43% in 12h, 33% in 24h and 27% in 36h. Sense ODNs had little effect. Meanwhile, the anti c-myc had inhibitory effect on production of Myc protein of the SMCs. Our results demonstrate that an antisense ODNs directed at the messenger RNA of myc decreases the expression of myc gone product and reduces SMCs proliferation induced by endothelin.

Abstract:The medium conditioned by cultured rabbit aortic smooth muscle cells (SMC—CM) was used as the source of chemotacic factor. Its chemotactic activity for smooth muscle cells (SMCs) and NIH 3T3 fibroblasts were examined by mieroporous filter assay. The results showedthat the SMC—CM was chemotactic for SMCs but not for NIH3T3 fibroblasts,and the effects of SMC—CM on SMC migration were considered to be chemotacic rather than chemokinetic in nature.

Abstract:On the model of endodenudation of the rats' thoracic aortae, the interaction of endotheliurn regrowth and intimal hyperplasis with release of endothelin was studied. The results indicated that endothelin was detected in the incubating media of rats' vessels with or without endotholium after procedure, but not in those without endotheiium in sham control. In preparations with endothelium or those without it, thrombin (4u/ml) stimulated the release of the peptide after endodenudation. Thus, we concluded that the increase of non—endothelium derired endothelin release is the major course of increased endothelin release after ballooning of rats' thoracic aortae.

Abstract:Our privious study proved that there were high affinity HDL_3—binding sites (HDL receptor) on the membrane of human SMMC—7721 hepatoeareinoma cells and the bindings of FITC-labelled Apo E—free HDL_3 (FITC—HDL_3) and native HDL_3 to the cells were competitive. This paper showed that modification of HDL_3 by aeetyl imidazol decreased its competitive binding to the cells. This inhibition was dose—dependent with the maximum inhibition at 1 mol/L of aeetyl imidazol. Our results suggest that tyrosin residue in HDL is present in the HDL binding recognition site and takes part in the binding to its receptor.

Abstract:A monoclonal antibody against human apolipoprotein B (apoB),B₅,was used to test the immunnoreactivities of apo B in unrelated individuals. We found that the apo B in each person exhibited one of the three binding patterns: high,intermediate,or low affinity. Genetic investigation showed that these binnding patterns might result from co-dominant transmission of a pair of apo B alleles (B₅~+/B₅~-). The frequency of gene B₅~+ was 0.593 and B₅~-was 0.407. We also found that the frequency of B₅~+/B₅~+ homozygotes in the hypercholesterolemic patient group was significantly lower than that in healthy subject group. The serum levels of total cholesterol, triglycerides, very low density lipoprotein (VLDL)—cholesterol, and VLDL—triglyeerides in B₅~+/B₅~+ homozygotes were significantly lower than those in B₅~-/B₅~-in the group of healthy subject. It is suggested that allele B₅~+ might be associated with lower serum concentrations of lipids, especially the concentration of cholesterol.

Abstract:氧化修饰低密度脂蛋白(Ox—LDL)在动脉粥样硬化发生发展中的作用越来越引起人们的重视。本文通过比较Ox—LDL和脂质过氧化降解产物丙二醛(MDA)修饰的低密度脂蛋白(MDA—LDL)在致泡沫细胞形成方面的差异,探讨了脂质过氧化对巨噬细胞的损伤在泡沫细胞形成中的作用。结果显示:Ox—LDL和MDA—LDL都可被巨噬细胞清道夫受体所识别,引起大量吞噬,造成细胞内胆固醇的聚集,但由MDA—LDL造成的细胞内胆固醇酯聚集可被高密度脂蛋白(HDL₃)所清除,而Ox—LDL造成的胆固醇酯聚集则不能。进一步的研究表明Ox—LDL和MDA—LDL对巨噬细胞HDL₃结合量及细胞内脂质过氧化物(LPO)含量的影响不同。虽然MDA—LDL和Ox—LDL处理巨噬细胞,都可使其HDL₃结合量有不同程度的下降,细胞内LPO含量有不同程度的升高,但当处理因素消除后,细胞继续培养时,由MDA—LDL处理的细胞其降低的HDL₃结合量又有一定的恢复,细胞LPO含量不再上升;而由Ox—LDL处理的细胞,其HDL₃结合量则继续下降,细胞LPO含量则继续升高。由Ox—LDL导致的巨噬细胞HDL₃结合量下降与细胞LPO含量升高之间呈负相关(r=-0.81,p<0.01)。用叔丁基脂氢过氧化物(tbooh)(1×10~(?)mol/L)对巨噬细胞损伤24小时,然后用两种修饰的LDL处理,则两种修饰LDL造成的胆固醇酯聚集都不能被HDL₃清除。本文结果提示Ox—LDL对巨噬细胞的脂质过氧化损伤可能在巨噬细胞向泡沫细胞转变过程中起着重要作用。

Abstract:Migration of smooth muscle cells (SMCs) into subendothelial space and their proliferation were key events in the atherogenesis, and were influenced by a variety of factors including PDGF, FGF, IGF, EGF,etc. It was known that SMCs could synthesize and secrete growth factors in a paracrine and autocrine manner. The SMCs conditioned medium (SMCs—CM) and the SMCs—sonicate (SMCs—son) were used as the source of growth factors,and their influence on the DNA synthesis of NIH 3T3 fibroblasts by ~3H—Thymidine incorporation. The resuits showed that SMCs—CM and SMCs—son both promoted the DNA synthesis of NIH 3T3 fibroblasts. These date suggest that growth factors synthesized by SMCs could be partly secreted out cells,among which some could bind with the receptors on SMC memberane,and the rest remained within the cells,stimulating the cells' prolifeartion.

Abstract:The accumulation of cholesteryl ester in mouse peritoneal macrophages and in bovine aortic smooth muscle cells by adding the mildly modified LDL (mm-LDL) was greatly enhancedwhen these cells were preincubated with monocyte colony-stimulating factor (M-CSF),indicating the synergism of mm-LDL and M-CSF on the lipid accumulation in cells. We also found that M-CSF increased the oxidative capability of cultured macrophages. This might be one of the mechanisms of synergism of mm-LDL and M-CSF.

Abstract:VLDL (200μg Protein/ml)was incubated with MΦ for 24 and 48 hours. The TBARS in VLDL after incubation for 24 and 48 hrs were 10.04±0.77 and 11.25±0.53nmol/mg protein respectively, which were much higher than that of controls (4.60±0.56,7.95±0.66 respectively). The MΦ modified VLDL migrated faster than the controls on agarose electrophoregram. In conclusion, VLDL could be oxidatively modified by MΦ in vitro. It suggests VLDL might be oxidited in Vivo. VLDL is also susceptible to oxidative modification by Cu²⁺ in vitro resulting in an increase in electrophoretie mobility and TBARS in the lipoprotein. Cu²⁺—Ox—VLDL had the potential ability to increase MC adherence to EC. The effects were concentration dependent. The percentage of MC adherence in n—VLDL group was much less than that in Ox—VLDL group (p<0.001). It suggests that Ox—VLDL plays an important role in MC adherence to EC.

Abstract:A special technique for "en face" artery endothelium preparation is intioduced, with which the nucleus labelled by ~3H—TdR can be seen with light microscopy. The endothelial regeneration canbe quantitatively analysed by calculating the labelling rate of endothelial ceils. The endothelial injury in quails with hypercholesterolemia was studied by this method. The more injury, the more cell regeneration. It is obvious that this method can be used in the study of any kind of endothelial injury.

Abstract:Monoclonal antibodies agaist human apolipoprotein E were prepared. Double McAbs Sandwich ELISA has been developed to quantitate apoE concentration in human serum. This paper presents the details of analytic procedure, and the evaluation of its specificity, precison, accuracy and sensitivity. The McAbs reacted specifically with apoE, no cross reaction with apoA Ⅰ、A Ⅱ, B, C Ⅰ , C Ⅱ , C Ⅲ was observed. The assay could detect 10ng of apoE, average recovery was 101.6%, the cofficients of variation of the intra—assay and inter—assay were 5.9% and 8.1%, respectively. The assay was used to quantitate apoE levels in normol persons and patients.

Abstract:Plasma concentrations of apoproteins A and B were investigated in forty—eight patients with coronary heart disease (CHD) and thirty—six health control subjects, in the meantime. serum triglyceride(TG). total Cholesterol (TC), HDL—C were also investgated. The results showed that plasma concentrations of apoA in CHD group were markedly lower than that in control group (p<0.01), apoB/apoA ratioes in CHD were significantly higher that in controls. (p<0.05). Serum concentrations of TG were markedly higher in CHD than that in normal group (p<0.01). No significant differences existed between CHD and normal group in plasma concentrations of apoB and TC. The decrease of plasma apoA level was the best parameter to distinguish CHD from non-CHD.