Infant Manipulative Actions upon Customary and Uncustomary Objects in Independent and Joint Activity

Eight 12 month-olds acting on objects were observed in two sessions: 1) the objects were home objects; 2) they were brought by the observer as new exemplars of previous toys. Infants were observed manipulating objects independently and with their mothers. Type and cognitive level of infant's actions were coded. Conventional actions were more frequent in joint than independent activity. In independent activity, conventional actions were more frequent with customary objects. High cognitive level was more frequent with customary objects. Acting with an adult is the major influential factor in promoting conventional usage of an object. However, acting on customary objects influences both conventional usage and organization of the actions. Notion of joint activity as a social practice rather than interactional event can be useful in accounting for this influence.     

5-HT2 receptor antagonists and migraine therapy

5-Hydroxytryptamine (5-HT; serotonin) has been implicated in the pathophysiology of migraine, and several drugs with potent 5-HT₂ receptor blocking activity (methysergide, pizotifen, cyproheptadine and mianserin) have been recognized as being clinically effective in migraine prophylaxis, although the selective 5-HT₂ receptor antagonist ketanserin (the principal agent used to identify 5-HT₂ receptor-mediated actions) seems to be ineffective in migraine. Pizotifen is the most widely used 5-HT₂ receptor antagonist in migraine prophylaxis, because of its superior efficacy compared with cyproheptadine, and because the incidence and severity of adverse effects with pizotifen is lower compared with methysergide and mianserin. These agents have additional antagonistic effects at histamine H₁, muscarinic cholinergic, ₁-adrenergic, ₂-adrenergic and dopamine receptors, but drugs which are selective for these non-5-HT receptors appear to be of no benefit in migraine. Actions mediated by 5-HT₂ receptors which could be of relevance to migraine comprise cranial vasoconstriction, increased cranial capillary permeability and platelet aggregation, and some central nervous system effects and neuroendocrine functions. Although pizotifen, cyproheptadine and mianserin are considered to be relatively specific for 5-HT₂ receptors, these agents and methysergide all share a high affinity for 5-HT_1C binding sites; ketanserin, however, has little affinity for these sites, thus activation of 5-HT_1C receptors may be an important step in the pathogenesis of migraine. It is not yet known which 5-HT_1C receptor-mediated actions of 5-HT are relevant to migraine, but some behavioural actions and cranial vasodilatation via release of endothelium-derived relaxing factor may be involved. If 5-HT_1C rather than 5-HT₂ receptor-mediated actions are important, then other 5-HT₂ receptor antagonists with a high affinity at 5-HT_1C binding sites, such as LY 53857, metergoline, mesulergine, ritanserin and SCH 23390, may also prove to be effective in migraine. The efficacy of methysergide may also depend on other 5-HT₁-like receptor-mediated actions such as cranial vasoconstriction, and inhibition of cranial vascular neurogenic inflammation. The efficacy of these agents implies that 5-HT is causally involved in at least some of the underlying pathophysiology of migraine.     

中草药的免疫作用

综述了中草药的免疫促进作用及抗炎免疫抑制作用，并分别阐述了其免疫有效成分、方剂、作用机理及研究进展。为开发、应用具有免疫作用的中草药提供了重要理论。     

海带药用研究进展

概述了近年来有关海带的化学成分和它在调节血脂、降血糖、降血压、抗凝血、抗肿瘤、抗突变和防辐射、抗病毒、增强免疫功能等方面的研究进展。     

滋阴泻火中药为主对改善性早熟儿童骨骼发育作用及机理的探讨

对女性特发性性早熟患儿50例采用滋阴泻火中药与甲地孕酮联合治疗,32例单纯使用甲地孕酮治疗,对照组25例不用药物治疗。对照组于1年后骨龄差/年龄差值从1.39±0.24上升为1.54±0.20(P<0.01),最终身高预测值从154.2±5.3cm下降至149.4±4.8cm(P<0.01)。单纯使用甲地孕酮治疗,对患儿骨龄提前及最终身高预测值下降趋势无明显影响。而联合治疗的患儿生长速率减慢,△BA/△CA值从1.36±0.19下降为0.65±0.16(P<0.001),最终身高的预测值从153.6±3.8cm增加至158.8±4.4cm(P<0.01)。研究结果表明,滋阴泻火中药可明显减慢性早熟儿童的骨骼生长,延缓其骨骼成熟,从而防止骨骺过早融合并改善最终身高。     

Increased Sensitivity to Long-term 5-Fluorouracil Exposure of Human Colon Cancer HT-29 Cells Resistant to Short-term Exposure

A 5-fluorouracil (5-FU)-resistant subline of human colon cancer HT-29 cells was developed by repeated 1-h exposure in vitro to 5-FU. This subline (HT-29/5-FU/S) had 8-fold resistance to 5-FU in a 1-h exposure assay. However, it had rather increased sensitivity to 5-FU when assayed after a continuous 96-h exposure to it. Significantly less 5-fluorouridine-5'-triphosphate was produced in the resistant cells, leading to a lower level of 5-FU incorporation into the cellular RNA. The reduced activity of orotate phosphoribosyltransferase might explain these results. In contrast, the HT-29/5-FU/S cells were more sensitive to the inhibition of in situ thymidylate synthase (TS) by 5-FU than were the parent cells. The lower in situ TS activity may have made HT-29/5-FU/S cells more sensitive to TS inhibition by 5-FU as compared with the parent cells. The fact that HT-29/5-FU/S was more resistant to short-term 5-FU exposure but more sensitive to long-term exposure than the parent line confirmed the existence of different modes of action of 5-FU, depending on the exposure time.     

人UrotensinⅡ在心血管系统中的生物学效应

Urotensin II最早是从鱼尾部下垂体中分离出的神经环肽,随后在一种欧洲绿蛙Rana ridibunda的脑中鉴别出来和从人体基因组中克隆出来。人Urotensin II(human urotensin II,hUII)有11个氨基酸残基组成,主要分布于心血管和神经系统。作为UT受体的一种内源性配体,hUII有广泛的生物学效应,如收缩和舒张血管,促进心肌细胞增殖,调节心功能,并在冠心病、心功能衰竭等某些心血管疾病的病理过程中起着重要的作用。本文就hUII在心血管系统方面的生物学效应作一简要的综述。     

昆明山海棠与雷公藤药理学对照研究

昆明山海棠和雷公藤同属卫矛科雷公藤属植物,在皮肤科临床应用广泛.两者不仅在某些化学结构方面相似,而且在药理作用方面也存在相似之处,均具有抗炎、抗肿瘤、免疫抑制、抗生育等多种药理作用.但是,由于两者都为有毒植物,在用于治疗的同时可产生一些毒性反应,甚至严重时可造成病人的死亡.为了便于临床更好地选用两种药物,特将两者的药理学作用作一综述.     

J江某段有机污染物对大鼠肝肾毒性作用

目的探讨J江某段有机污染物对大鼠的肝肾毒性。方法固相萃取法提取江水中有机物,分别以相当于源水4,24,144 L/(kg.bw)的剂量给予大鼠亚急性(14 d)灌胃染毒,观察肝、肾组织病理改变、肝肾功能相关血清生化指标及脂质过氧化水平。结果在144 L/(kg.bw)剂量组,染毒大鼠肝、肾组织可出现以空泡变性为特征的病理损伤;谷草转氨酶(AST)、尿酸(UA)、甘油三酯(TG)水平与对照组间差异有统计学意义(P<0.05);肝、肾组织中总超氧化物歧化酶(T-SOD)活力和丙二醛(MDA)含量显著升高。结论在较高的实验剂量时,J江某段有机提取物具有一定的肝肾毒性,脂质过氧化作用可能是其损伤肝肾机制之一。     

新型严重脓毒症治疗剂--重组人激活蛋白C

通过文献检索综述了用于治疗成人严重脓毒症的药物重组人激活蛋白C的药理作用、药代动力学及临床评价.在1690名患者参加的PROWESS临床试验中,它可以降低严重脓毒症患者28天治疗期内各种原因的死亡率且使用较安全.