Does the conformation of adsorbed fibrinogen dictate platelet interactions with artificial surfaces?

Platelet activation by polymer surfaces is thought to require preliminary adsorption of fibrinogen and perhaps changes in fibrinogen conformation. We measured fibrinogen adsorption by a series of polymers by two methods, using either 125I-labeled fibrinogen or 125I-labeled antifibrinogen antibodies, and correlated the results with platelet reactivity (retention and secretion) in columns of beads coated with the polymers. For polyalkyl methacrylates with 1 to 4 carbon side chains, platelet reactivity varied directly with increasing length of the alkyl side chain and with the quantity of bound fibrinogen recognizable by antifibrinogen antibody but not with the total quantity of fibrinogen adsorbed. The same pattern of results was seen with five antibody preparations, including affinity-purified Fab fragments against the D or E domain of fibrinogen. Tests of platelet retention and fibrinogen binding to four polyalkyl acrylates and to three unrelated polymers (polystyrene, polymethyl methacrylate, and a polyether polyurethane) indicated that platelet retention correlated positively with both total fibrinogen binding and with the amount of antibody-recognizable fibrinogen bound. Drugs that block platelet aggregation, but not adhesion, did not alter the hierarchy of platelet retention to the polyalkyl methacrylates. These data suggest that, contrary to previous views, platelet adhesion to artificial surfaces increases with increasing surface coverage of adsorbed fibrinogen if the bound fibrinogen maintains a conformation such that its functional domains remain recognizable by antibody probes.     

2,4-二氨基-5-取代苄基嘧啶类化合物的合成及其抑酶活性

本文设计并合成了18个在苄基上带有不同体积取代基的2,4-二氨基-5-取代苄基嘧啶类化合物。测定了这些化合物对乳酪菌二氢叶酸还原酶及对鸡肝二氢叶酸还原酶的表观50%抑制作用。其中2,4-二氨基-5-(3′-羟基-4′-甲氧基)苄基、2,4-二氨基-5-(3′-甲氧基-4′-甲氧乙氧基)苄基嘧啶对上述二氢叶酸还原酶(DHFR)的选择性较好。     

HPLC法同时测定复方环丙沙星滴鼻液中三组分的含量

目的建立同时测定复方环丙沙星滴鼻液中盐酸麻黄碱、乳酸环丙沙星、马来酸氯苯那敏含量的HPLC方法。方法采用：PurospherSTAR RP-18色谱柱（4.6 mm×150 mm,5μm）,以磷酸盐缓冲液（p H 3.0±0.1）-乙腈（82∶18）为流动相,调节流速为1.0 ml·min-1,在210 nm波长处同时检测3组分。结果盐酸麻黄碱、乳酸环丙沙星和马来酸氯苯那敏分别在20.14~161.12、12.05~96.38和6.18~49.47μg·ml-1浓度范围内线性关系良好,相关系数分别为0.9996、0.9999和0.9999,平均回收率分别为101.11%、99.83%和101.07%。结论该方法快速简便、重复性、耐用性好,可用于该制剂中3组分的测定。     

女儿茶多糖NLC-A的分离纯化及化学结构

女儿茶为民间常用中草药。经水提取,去蛋白及小分子杂质得到女儿茶多糖(NLC-A)粗制品。再经Cellex D,Sepharose 6B和Sephadex G-100相继柱层析,得到均一组分NLC-A,分子量为1.2×10⁴,NLC-A经全水解,甲基化反应,过碘酸盐氧化,Smith降解,KI-I₂反应和IR证明其结构为以α(1→4)-D-葡萄糖为主链,并在o-6位有分枝的葡聚糖。     

Peritoneal implants from ovarian tumors: CT findings

Metastatic peritoneal implants were assessed preoperatively with computed tomography (CT) in 38 patients with ovarian tumors. In the 106 biopsy specimens of gross peritoneal implants and the 118 random biopsy specimens obtained from these patients, metastatic deposits were detected in 27 of 38 (71%) patients and in 104 biopsy sites. CT depicted metastatic lesions in 17 of 27 (63%) patients and in 63 of 104 (61%) biopsy sites. The three sites most commonly involved were the right subphrenic region, the greater omentum, and the pouch of Douglas. The usefulness of CT in detecting lesions depended mainly on the location of the implant and the presence of adjacent ascites, rather than on lesion size.