新疆紫草抗肿瘤作用机制研究进展

文章主要对新疆紫草抗肿瘤作用机制的研究成果进行了系统综述和评论。简要介绍了新疆紫草的物质基础,详细评述了其主要活性成分紫草素及其衍生物抑制多种肿瘤细胞的生长、增殖,致肿瘤细胞凋亡作用机制的最新进展,并对其应用前景进行了展望。     

65例慢性阻塞性肺疾病患者血降钙素原变化分析

目的 分析65例慢性阻塞性肺疾病急性加重期（AECOPD）患者血清降钙素原变化及其指导意义.方法 本研究纳入65例AECOPD患者,随机分成A组（PCT指导组）、B组（一般治疗组）.A组按患者血PCT高低及变化判断抗生素的使用时间;B组根据患者临床症状判断抗生素的使用时间.分别记录A、B两组抗生素的使用时间、住院天数、临床有效率,加重例数和死亡例数用于评估.结果 A组的抗生素使用时间多为7～10 d：B组大多数为2周以上,二者有明显差异（P＜0.05）;A、B两组住院时间也存在显著差异（P＜0.05）.结论 PCT在AECOPD患者治疗中,具有指导意义,能够有效缩短抗生素使用时间及缩短住院天数.     

Identification of high-affinity (Kd 0.35 mumol/L) and low-affinity (Kd 7.9 mumol/L) platelet binding sites for ADP and competition by ADP analogues

Steady-state binding of ADP to blood platelets and isolated membranes has not previously been obtained because of complications arising from metabolism of the ligand and dilution due to its secretion from storage granules. In the present studies, competition binding isotherms (n = 9) using paraformaldehyde-fixed platelets showed that [2-3 H]ADP bound to two sites with a small amount (approximately 5% of total) of nonspecific binding: 410,000 +/- 40,000 sites of low affinity (Kd 7.9 +/- 2.0 mumol/L) and 160,000 +/- 20,000 sites of high affinity (Kd 0.35 +/- 0.04 mumol/L) corresponding to the ADP concentration required for activation in fresh platelets (0.1-0.5 mumol/L). All agonists and antagonists examined were able to compete with ADP at the high-affinity site. The strong platelet agonists 2-methylthio ADP and 2-(3- aminopropylthio)ADP competed with ADP at the high-affinity site with dissociation constant values of 7 mumol/L and 200 mumol/L, respectively. The partial agonist 2',3'-dialdehyde ADP and the weak agonist GDP also competed at the high-affinity site with Kd values of 5 mumol/L and 49 mumol/L, respectively. The sequence of binding affinities of other adenine nucleotides at the high-affinity site corresponded to their relative activities as known antagonists of platelet activation by ADP; namely, ADP(Kd 0.35 mumol/L) approximately equal to ATP (Kd 0.45 mumol/L) much greater than AMP (Kd 360 mumol/L). Adenosine and 2-chloroadenosine did not compete with ADP. ADP binding to the high-affinity site was inhibited by p-mercuribenzene sulfonate (Ki 250 mumol/L) but only very weakly by 5'-p- fluorosulfonylbenzoyladenosine (Ki 1 mmol/L). All the above nucleotides also competed with ADP at the low-affinity sites but, because of the high concentrations of competing nucleotide required, dissociation constants at this site were obtained only for ATP (21 mumol/L), 2-MeS ADP (200 mumol/L) and 2',3'-dialdehyde ADP (270 mumol/L). 8-Bromo ADP competed strongly with ADP at the high-affinity site (Kd 0.40 mumol/L) but weakly if at all at the low-affinity site. 8-Bromo ADP inhibited platelet activation induced by ADP (EC50 approximately 100 mumol/L) but not by collagen, thrombin, or ionophore A23187.(ABSTRACT TRUNCATED AT 400 WORDS)     

唐古特红景天降低大鼠低氧性肺动脉高压的作用及对ET-1, eNOS mRNA和蛋白表达的影响

目的:研究唐古特红景天95%乙醇提取物对大鼠慢性低氧性肺动脉高压(HPH)的作用及其分子机制。方法:雄性Wistar大鼠随机分为对照组、低氧组、低氧+生理盐水组、低氧+低剂量药物组(1.25 g.kg-1.d-1)、低氧+高剂量药物组(2.5 g.kg-1.d-1)5组,每组15只。除对照组外,其余各组动物均置于低压氧舱内(模拟海拔4 500 m的高原环境),每24 h开舱0.5 h进行灌药等处理,连续30 d。检测各组大鼠的肺血流动力学变化、右心室肥厚指数;光镜观察直径50～100μm的肺动脉管壁厚度占外径的百分比(WT%);采用实时荧光定量PCR方法,检测各组动物肺组织内皮素-1(ET-1)和内皮细胞一氧化氮合酶(eNOS)mRNA的表达;采用ELISA法检测各组动物血清ET-1和eNOS蛋白的含量。结果:与低氧对照组和低氧生理盐水组相比,高剂量唐古特红景天干预,具有以下药理作用:①降低大鼠的平均肺动脉压(mPAP),右心室肥厚指数(RV/LV+S),血红蛋白含量(Hb),红细胞压积(Hct)(P<0.01);②减轻大鼠肺动脉的肌化程度(P<0.05);③降低大鼠肺组织ET-1 mRNA表达,上调大鼠肺组织内皮细胞(eNOS)mRNA表达(P<0.05);④降低大鼠血清ET-1蛋白的含量,上调大鼠血清内皮细胞eNOS蛋白的含量(P<0.05)。结论:唐古特红景天对于HPH的形成具有一定的防治作用,其药理作用机制与上调eNOS mRNA和蛋白表达、抑制ET-1 mRNA和蛋白表达有关。     

Synergistic effects of butyrate on platelet responses to arachidonate, A23187, PGE1, and forskolin

With eukaryotic cells, butyrate is known to induce a series of morphological and biochemical changes that mimic cellular differentiation. With platelets, we have found that butyrate (10 mmol/L) caused an approximately threefold increase in sensitivity to calcium ionophore A23187 and arachidonate. Maximum aggregation was observed at agonist concentrations of 3 mumol/L and 170 mumol/L, respectively, as compared with required concentrations of 10 mumol/L and 400 mumol/L in the absence of butyrate. Similar effects were seen with isobutyric acid, and about one-half the effect was shown with valerate and caproate, but lower homologues showed no synergistic effect. No ultrastructural changes were observed in platelets incubated with butyrate, and the aggregation effects were reversible and returned to normal on removal of butyrate. Membrane fluidity was unchanged by butyrate as measured by changes in the fluorescence depolarization of diphenylhexatriene. Butyrate caused a 60% to 70% increase in the uptake of 3H-arachidonate. Butyrate also potentiated the inhibition of platelet function by prostaglandin E1 and forskolin and uptake of 3H- forskolin was increased approximately 20%. In contrast, platelet response to other agonists (ADP, epinephrine, collagen, thrombin, and platelet-activating factor) was essentially unaffected by butyrate. These results suggest that butyrate may increase the uptake of certain hydophobic agonists and antagonists by platelets. Similar mechanisms for uptake of endogenous effectors may explain the response of eukaryotic cells to butyrate in culture.