川芎嗪对血小板中肌醇磷脂和2OK蛋白质磷酸化的抑制作用

在Mg~(2+)存在下.用血小板膜与(γ—~(32)P)ATP保温,以观察川芎嗪对~(32)P掺入磷脂和蛋白质的影响,结果表明:血小板膜中存在磷脂酰肌醇(PI)激酶和磷脂酰肌醇—4—磷酸(PIP)激酶,而胞浆中缺乏或极少;ATP促进肌醇磷脂磷酸化;川芎嗪抑制血小板中PIP和20K蛋白质的磷酸化.半数抑制浓度分别为40μmol·L~(-1)和110μmol·L     

粉防己碱对兔血小板聚集和血小板活化因子生成的影响(英文)

目的:探讨粉防己碱(Tet)对兔血小板聚集和PAF生成的影响.方法:卡西霉素(Cal)和PAF诱导血小板聚集的聚集率和Tet对血小板聚集的抑制率被测定;给予或未给予Tet处理之血小板用Cal刺激释放PAF的量也被测定.结果:在4—64 μmol·L~(-1)浓度范围,Tet明显抑制Cal和PAF诱导的血小板聚集.IC_(50)值分别为8.6μmol·L~(-1)和14.0μmol·L~(-1).Tet也浓度依赖性的抑制Cal诱导血小板释放PAF,IC_(50)值为21.0μmol·L~(-1).结论:Tet抑制血小板聚集作用与抑制内源性PAF生成有关.     

HPLC法同时测定人血浆中5-氟尿嘧啶及其活性代谢物5-氟-2′-脱氧尿嘧啶核苷的浓度

目的:建立一种同时测定人体血浆中5-氟尿嘧啶及其活性代谢物5-氟-2′-脱氧尿嘧啶核苷浓度的HPLC法。方法:以肌苷为内标,血浆样品用硝酸银(10%)沉淀蛋白质,采用C_(18)柱,检测波长为266nm,流动相:0.01mol·L~(-1)磷酸盐(用2mol·L~(-1)氢氧化钠溶液调pH为7.0)-甲醇(96∶4),流速1.0mL·min~(-1),柱温为45℃。结果:5-氟尿嘧啶和5-氟-2′-脱氧尿嘧啶核苷分别在0.1～20μg·mL~(-1)(r=0.9997)和0.2～40μg·mL~(-1)(r=0.9997)浓度范围内线性关系良好,最低检测浓度分别为5和10ng·mL~(-1),方法回收率分别为98.2%～101.2%、99.5%～102.3%,日内、日间RSD均小于6%。结论:方法灵敏、快速、准确,适用于临床上测定5-氟尿嘧啶及其活性代谢物5-氟-2′-脱氧尿嘧啶核苷的血药浓度及药动学的研究。     

甲基黄酮醇胺对分离的胎鼠脑细胞内游离钙浓度的影响(英文)

目的:观察甲基黄酮醇胺(MFA)对胎鼠脑细胞内游离钙浓度在静息以及激动剂存在时的作用。方法:用钙离子荧光染料Fura 2-AM负载后,测定分离的胎鼠脑细胞内游离钙浓度([Ca~(2 )]_i)及其变化。结果:在含钙1.3mmoL·L~(-1)的Hanks’液中,[Ca~(2 )]_i为197±20nmol·L~(-1)(n=44)。MFA0.15mmol·L~(-1)对静息脑细胞内钙浓度无明显影响。在细胞外钙1.3mmol·L~(-1)条件下,MFA(0.03—0.3 mmoL·L~(-1))浓度依赖性地抑制高钾去极化导致的[Ca~(2 )]_i升高,IC_(50)为0.14(95％可信限:0.05—0.42)mmoL·L~(-1)。在较高浓度时,MFA(0.15—0.3mmoL·L~(-1))也可抑制谷氨酸兴奋所引起的[Ca~(2 )]_i,IC_(50)为0.20(95％可信限:0.01—3.40)mmoL·L~(-1)。结论:MFA抑制高钾去极化引起的[Ca~(2 )]_i升高,在较高浓度时也拮抗谷氨酸兴奋所致的[Ca~(2 )]_i升高。     

槲皮素对血小板聚集和胞浆游离钙的影响(英文)

目的:研究槲皮素对凝血酶诱导的血小板聚集和胞浆游离钙浓度的影响及钙对槲皮素的血小板聚集抑制效应的作用。方法:用荧光钙离子指示剂观察槲皮素对血小板胞浆游离钙的影响.结果:槲皮素明显抑制凝血酶诱导的血小板聚集和游离钙的升高.IC_(50)和95％可信区间分别为146.2(92.4～231.3)和78.5(49.5—124.4)μmol·L~(-1).槲皮素对血小板的抑制作用可被钙翻转.槲皮素对凝血酶诱导的钙释放无影响.结论:抑制钙内流是槲皮素抑制血小板聚集和[Ca~(2 )]_i升高的机制.     

眼镜蛇毒蛋白酶natrahagin水解纤维蛋白原的特性及对人血小板聚集的影响(英文)

目的:研究natrahagin水解纤维蛋白原的特性及其对血小板聚集的影响。方法:SDS-PAGE,水解纤维蛋白原活性测定,血小板聚集实验。结果:Natrahagin与纤维蛋白原以1:50(w/w)孵育,5min内A_α-链几乎完全降解,γ-链的完全降解则至少需6h;其水解可凝固纤维蛋白原的活性为0.349±0.044g·min~(-1)·g~(-1)。Natrahagin浓度依赖性地抑制利托菌素对富血小板血浆和凝血酶(80U·L~(-1))对洗涤血小板的聚集反应,IC_(50)(95％可信限)分别为56(40-79)和3.3(1.4-8.0)mg·L~(-1)。但即使natrahagin达200mg·L~(-1),对ADP和胶原诱导的血小板聚集仍无抑制作用。结论:Natrahagin是一种α,γ-纤维蛋白原溶解酶,可选择性抑制血小板膜糖蛋白Ib介导的血小板聚集。     

DDPH抑制豚鼠单个心室肌细胞L-钙电流和钠电流(英文)

目的:研究1-(2,6-二甲基苯氧基)-2-(3,4-二甲氧基苯乙氨基)丙烷盐酸盐(DDPH)对豚鼠心室肌细胞L-型钙电流和钠电流的作用。方法:全细胞膜片箝技术。结果:(1)DDPH(3-300μmol·L~(-1))浓度依赖性地抑制L-型钙电流,IC_(50)为28.5μmol·L~(-1)(95％可信限:14.3-42.7μmol·L~(-1))。维拉帕米0.3-30μmol/L浓度依赖性地抑制钙电流,IC_(50)为1.8μmol·L~(-1)(95％可信限:1.3-2.3μmol·L~(-1))。美西律100μmol·L~(-1)对钙电流无影响。DDPH30μmol·L~(-1)使用依赖性阻滞钙电流,1Hz时抑制率为58％±13％(n=5,P<0.01),3Hz时为76％±11％(n=5,P<0.01)。(2)DDPH(20-320μmol·L~(-1))浓度依赖性抑制钠电流,IC_(50)为89.0μmol·L~(-1)(95％可信限:68.7-109.3μmol·L~(-1))。美西律抑制钠电流的IC_(50)为32.2μmol·L~(-1)(95％可信限:11.7-52.7μmol·L~(-1))。维拉帕米10μmol·L~(-1)对钠电流无影响(P>0.05).DDPH80μmol·L~(-1)对钠电流无使用依赖性阻滞。结论:DDPH抑制豚鼠心室肌细胞L-型钙电流和钠电流,但抑制钙电流的作用弱于维拉帕米,抑制钠电流的作用弱于美西律。     

L-焦谷氨酸对抗谷氨酸钠诱发的大鼠皮层神经元损伤

目的:在大鼠皮层神经元研究L-吡咯烷酮羧酸(L-PGA)对谷氨酸钠(Glu)诱发神经毒性的拮抗作用。方法:原代培养的皮层神经元取自16d龄的胎鼠,与Glu作用30分钟,24小时后测定神经元的存活及培养介质中亚硝酸盐的浓度;以Fura 2-AM为细胞内[Ca~(2 )]_i荧光探针,AR-CM-MIC阳离子测定系统测定[Ca~(2 )]_i。结果:L-PGA 10-80μmol·L~(-1)浓度依赖地抑制Glu 500μmol·L~(-1)引起的神经损伤,其IC_(50)为(41±9)μmol·L~(-1),95％可信区间:(30.3-54.7)μmol·L~(-1)。L-PGA也能浓度依赖地降低Glu引起的NO释放。L-PGA 1,3,10,30,100μmol·L~(-1)对Glu 100μmol·L~(-1)引起的[Ca~(2 )]_i升高的抑制率分别为20.5％,34.4％,47.7％,70.6％,80.4％。结论:L-PGA可能通过抑制NO形成或细胞内Ca~(2 )浓度的升高而拮抗Glu的神经毒性。     

Tyrphostins对大鼠肝酪蛋白激酶Ⅱ活性的影响(英文)

目的:研究Tyrphostins(AG123,AG1394,AG114,AG1109,AG555)对酪蛋白激酶Ⅱ(CKⅡ)活性的影响。方法:依次采用DEAE-纤维素和肝素-Sepharose层析将大鼠肝CKⅡ纯化了104倍,通过将去磷酸化的酪蛋白和[γ-~(32)P)ATP与CKⅡ保温的方法测定CKⅡ的活性。结果:AG213对CKⅡ有强烈的抑制作用(IC_(50)44.7μmol·L~(-1)[41.5μmol·L~(-1),47.9μmol·L~(-1)]),AG1394(144μmol·L~(-1))对CKⅡ的抑制率为89％。AG114和AG1109对CKⅡ也有明显的抑制作用,而AG555对CKⅡ的活性没有影响。结论:某些tyrphostins是CKⅡ抑制剂。     

茶碱、咯利普兰和acetamide—45对GL62酵母细胞表达的人磷酸二酯酶4A的抑制作用

目的:研究GL62 酵母细胞中磷酸二酯酶4A(PDE4A)的诱导表达和茶碱、咯利普兰、N-对氟苄基-3-[(N-4-吡啶)-乙酰胺]-吲哚45(acetamide-45)对GL62酵母细胞诱导提取物中PDE4A活性的抑制作用.方法:克隆了人PDE4A基因的GL62酵母细胞在CuSO_4 150μmol/L条件下诱导表达PDE4A并提取,用高效液相色谱法测定PDE4A的活性.结果:GL62酵母细胞在CuSO_4诱导下的表达产物蛋白分子在62 kDa和83 kDa之间,表达产物的PDE4A的活性在3 h达到最大为(188±23)μmol·g~(-1)·min~(-1),其米氏常数 K_m为(17.7±2.6)μmol·L~(-1).茶碱,咯利普兰和acetamide-45对诱导提取物PDE4A活性的IC_(50)(95 ％可信限)分别为1642(989-2727),4.58(3.45-6.08)和275(170-444)μmol·L~(-1).结论:GL62酵母细胞经CuSO_4诱导可表达PDE4A,茶碱、咯利普兰和 acetamide-45能抑制其活性,GL62酵母细胞的诱导表达提取物可用来研究PDE4A及其抑制剂.     

Synthesis and antiretrovirus properties of 5'-isocyano-5'-deoxythymidine, 5'-isocyano-2',5'-dideoxyuridine, 3'-azido-5'-isocyano-3',5'-dideoxythymidine, and 3'-azido-5'-isocyano-2',3',5'-trideoxyuridine

The 5'-azidonucleosides 3 and 4 were obtained by treating thymidine and 2'-deoxyuridine with TPP/DEAD/HN3. The 3'-O-silylated 5'-azido-5'-deoxythymidine 5 and the corresponding 2'-deoxyuridine derivative 6 were transformed to the formamides (7 and 8, respectively) and dehydrated to the protected 5'-isocyano derivatives 9 and 10; deblocking gave 5'-isocyano-5'-deoxythymidine (11) and 5'-isocyano-2',5'-dideoxyuridine (12). 2,3'-Anhydro-5'-formamido derivatives of thymidine and 2'-deoxyuridine (19 and 20, respectively) were prepared by three different ways. In the most direct synthesis 3 and 4 were transformed to the 2,3'-anhydro-5'- azidonucleosides 17 and 18 by using TPP/DEAD; following the reaction with TPP/HCO2COCH3 gave 19 and 20. Nucleophilic opening reaction with LiN3 yielded the 3'-azido-5'-formylamino derivatives 21 and 22. Dehydration to 3'-azido-5'-isocyano-3',5'-dideoxythymidine (23) and 3'-azido-5'-isocyano-2',3',5'-trideoxyuridine (24) was achieved with tosyl chloride/pyridine. In contrast with 3'-azido-3'-deoxythymidine, compounds 11, 12, 23, and 24 were devoid of any marked inhibitory effect against DNA and RNA viruses including human immunodeficiency virus type I (HIV).     

Behavioural effects of dibutyryl cyclic 3',5' AMP, noradrenaline and cyclic 3',5' AMP in rats

It was shown that dibutyryl cyclic AMP (DAMP) injected intraventricularly in doses of 100–200 μg in rats causes the increase of locomotor and exploratory activity and convulsions, depending on the dose. DAMP increased excitatory behavioural effects of noradrenaline (NA) injected intraventricularly in doses of 10 or 50 μg. NA in a dose of 200 μg abolished convulsions evoked by DAMP. Cyclic AMP (cAMP) injected intraventricularly in doses of 100–400 μg had no effect on the rat's behaviour. Pretreatment of rats with dimethylsulphoxide and with theophylline caused in some animals behavioural phenomena after injection of cAMP, similar to the behavioural symptoms evoked by DAMP.     

Synthesis and biological activities of 5-trifluoromethyl-5'-azido-2',5'-dideoxyuridine and 5-trifluoromethyl-5'-amino-2',5'-dideoxyuridine.

5-Trifluoromethyl-2'-deoxyuridine (1) was tosylated with p-toluenesulfonyl chloride in dry pyridine at 3 degrees to give 5-trifluoromethyl-5'-O-(p-tolylsulfonyl)-2'-deoxyuridine (2), which was converted to 5-trifluoromethyl-5'-azido-2',5'-dideoxyuridine (3) by reacting with lithium azide in N,N-dimethylformamide at 85-90 degrees for 2 h. Compound 3 was then hydrogenated in ethanol-water (1:1, v/v) at room temperature and 35 psi of hydrogen pressure, using 10% palladium on charcoal as cstalyst, to yield 5-trifluoromethyl-5'-amino-2',5'-dideoxyuridine (4). Compound 4 is about fourfold less potent than compound 1 as an antiviral agent but is about 40-fold less toxic to the host Vero cells. Thus the therapeutic index of compound 1 has been improved by a factor of 10 by replacement of the 5'-hydroxyl with an amino group. Compound 1, however, is more than 100-fold more inhibitory to Sarcoma 180 cells in culture relative to compound 4. Compound 3 is markedly less potent than compound 1 or 4 as either an antiviral or an antineoplastic compound.     

Inhibition of 3,3',4,4',5-Pentachlorobiphenyl-Induced Chicken Embryotoxicity by 2,2',4,4',5,5'-Hexachlorobiphenyl

3,3',4,4',5-Pentachlorobiphenyl (pentaCB) caused a dose-dependentinduction of chicken embryolethality, malformations, edema,and liver lesions at doses ranging from 0.5 to 12.0 µg/kg.In contrast, no embryotoxicity was observed after treatmentwith 10, 25, or 50 mg/kg 2,2',4,4',5,5'-hexaCB. In eggs cotreatedwith 2.0 µ/kg, 3,3',4,4',5-pentaCB plus 10, 25, or 50mg/kg 2,2',4,4',5,5'-hexaCB, there was significant protectionfrom 3,3',4,4',5-pentaCB-induced embryo malformations, edema,and liver lesions, whereas no inhibition of embryolethalitywas observed. These results further extend the response-specificnonadditive interactions of binary mixtures of polychlorinatedbiphenyls (PCBs) and should be considered in the developmentof approaches for hazard assessment of PCB mixtures and relatedcompounds.     

Synthesis and complement inhibitory activity of B/C/D-ring analogues of the fungal metabolite 6,7-diformyl-3',4',4a',5',6',7',8',8a'-octahydro-4,6',7'-trihydroxy- 2',5',5',8a'-tetramethylspiro[1'(2'H)-naphthalene-2(3H)-benzofuran

This paper reports the synthesis and the bioassay of 4-methoxy- and 4-hydroxyspiro[benzofuran-2(3H)-cyclohexane] partial analogues (5) of the complement inhibitory sesquiterpene fungal metabolite 6,7-diformyl-3',4',4a',5',6',7',8',8a'-octahydro-4,6',7'-trihydroxy-2',5',5',8a'-tetramethylspiro[1'(2'H)-naphthalene-2(3H)-benzofuran] (1a, K-76) and its silver oxide oxidized product (1b, K-76COOH). The described target compounds represent spirobenzofuran B/C/D-ring analogues lacking the A-ring component of the prototype structure. The target compounds were evaluated by the inhibition of total hemolytic complement activity in human serum. It was observed that the structurally simplified analogue 4-methoxyspiro[benzofuran-2(3H)-cyclohexane]-6-carboxylic acid (5a) exhibited an IC(50) = 0.53 mM similar to the IC(50) = 0.57 mM that was observed for the natural product derivative 1b. Exhibiting an IC(50) = 0.16 mM, the three-ringed partial structure 6-carboxy-7-formyl-4-methoxyspiro[benzofuran-2(3H)-cyclohexane] (5k)was found to be the most potent target compound. Like the natural product, 5k appears to inhibit primarily at the C5 activation step and inhibits both the classical and alternative human complement pathways. Several other analogues inhibited complement activation in vitro at concentrations similar to those required for inhibition by the natural product 1b.     

Characterization of the Photolysis of 2,4,5,2',4',5'-Hexabromobiphenyl

Characterization of the Photolysis of 2,4,5,2',4',5'-Hexabromobiphenyl.MILLIS, C. D., AND AUST, S. D. (1985). Fundam. Appl. Toxicol.5, 546–554. 2,4,5,2',4',5'-Hexabromobiphenyl (2,4,5-HBB)was irradiated with ultraviolet light in hexane with stirring,and photolysis was monitored by gas chromatography (GC). 2,4,5-HBBdecomposed at an average rate of 0.66±0.02 µmol/minand the reaction appeared zero order from 0.159 to 1.59 mM 2,4,5-HBB.Several polybrominated biphenyl (PBB) congeners were identifiedas photoproducts of 2,4,5-HBB. 2,4,5,2',5'-Pentabromobiphenyl(-PBB), formed by para debromination, accumulated at a higherrate than did 2,4,5,3',4'-PBB, formed by ortho debromination.2,4,5,2',4'-PBB was formed by meta debromination. 3,4,3',4'-Tetrabromobiphenyl(-TBB) was found as a secondary photoproduct, formed by orthodebromination of 2,4,5,3',4'-PBB. 2,5,2',5'-TBB and 2,4,2',5'-TBBwere formed by debromination of 2,4,5,2',5'-PBB para and meta,respectively. 2,5,3',4'-TBB could be formed by either orthodebromination of 2,4,5,2',5'-PBB or para debromination of 2,4,5,3',4'-PBB.Rates of degradation and accumulation of the penta- and tetrabrominatedbiphenyls were also studied. The ultraviolet spectra of the2,4,5-HBB photolysis mixture, as well as the purified components,were studied and are also reported     

Toxicity of 3,4,5,3',4',5'-hexabrominated biphenyl and 3,4,3',4'-tetrabrominated biphenyl

Immature male rats were given a single equimolar dose (21.3 mumol/kg body wt) of 3,4,5,3',4',5'-hexabromobiphenyl (HBB) or 3,4,3',4'-tetrabromobiphenyl (TBB) and terminated at various times up to 14 days after treatment. Hepatic microsomal aryl hydrocarbon hydroxylase (AHH) activity for the TBB treatment group was maximal at Day 2 and then steadily decreased, whereas this activity was induced in 1 day and remained high for the HBB treatment group. Tissue concentrations of HBB appeared to be unchanged over time whereas tissue concentrations of TBB decreased in a biphasic manner. Rates of in vitro metabolism of TBB with hepatic microsomes from TBB-treated animals showed a similar time-course relationship to AHH induction. HBB caused moderate to severe hepatic changes while TBB-treated rats had only mild hepatic changes. The relative binding of TBB by the hepatic receptor for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was about 10 times that of HBB. The results suggest that even though the receptor-binding affinities imply that TBB should be more toxic than HBB, it is less toxic than HBB because it is metabolized. Studies with the chlorinated analogs of TBB and HBB suggested that PCB behave similarly. These results also suggest that receptor binding and AHH induction do not accurately reflect toxicity for polyhalogenated aromatic hydrocarbons which are metabolized, presumably because continued occupation of the receptor and persistent induction of some enzyme activity are required for toxicity.     

Fluorinated pyrimidine nucleosides. 4. Synthesis and antitumor testing of a series of 2',5'-dideoxy- and 2',3',5'-trideoxynucleosides of 5-fluorouracil

Dideoxy- and trideoxynucleosides of 5-fluorouracil have been synthesized for antitumor evaluation. 2',5'-Dideoxy-5-fluorouridine (3) was prepared from 2'-deoxy-5-fluorouridine (1) by iodination using methyltriphenoxyphosponium iodide, followed by catalytic reduction. 1-(2',5'-Dideoxy-beta-D-threo-pentofuranosyl)5-fluorouracil (4) was prepared from 3 by mesylation, followed by alkaline hydrolysis. 2',3',5'-Trideoxy-5-fluorouridine (13), a methyl homologue of Ftorafur (17), was synthesized by two routes: Treatment of the 3'-mesylate 8 with potassium tert-butoxide yielded the 2',3'-unsaturated derivative 12, which on hydrogenation yielded 13. Alternatively, treatment of 1 with a large excess of methyltriphenoxyphosphonium iodide produced several products, including two 3'-epimeric diiodo compounds (14 and 15), each of which could be hydrogenated to 13. The major product from this iodination reaction was characterized 3-(2',3'-anhydro-2',5'-dideoxy-5'-iodo-beta-D-threo-pentofuranosyl)-5-fluorouracil (5), presumably produced by rearrangement of the corresponding 1-isomer 9. The dideoxy compounds 3 and 4, as well as the trideoxy compound 13, were tested against sarcoma 180 in mice in comparison with 5-flourouracil, FUDR (1), and Ftorafur (17).