Enhanced stimulus-reward learning by intra-amygdala administration of a D3 dopamine receptor agonist

The amygdala is considered to be a critical neural substrate underlying the formation of stimulus-reward associations, and is known to receive substantial innervation from dopaminergic neurons located within the ventral mesencephalon. However, relat- ively little is known about the function of the mesoamygdaloid dopamine projection in stimulus-reward learning. Recently, we have found post-session intra-amygdala microinjections of d-amphetamine to enhance appetitive Pavlovian conditioning as assessed in a discriminative approach task. In the present study, we have examined the effects of dopamine receptor agonists possessing relative selectivity for the D₁, D₂ and D₃ receptor subtypes in order to examine more fully the role of the mesoamygdaloid dopamine projection in stimulus-reward learning. Thus, subjects were trained to associate an initially neutral stimulus (CS⁺) with 10% sucrose reward (US). A second, control stimulus (CS⁻) was also presented but never paired with sucrose reward. In order to measure specifically the conditioned response to CS⁺/CS⁻ presentation, responding during CS and US presentations was measured separately. Immediately following each training session, subjects received bilateral intra-amygdala infusion of 0.1, 1 or 10 nmol/side of SKF-38393, quinpirole or 7-OH-DPAT. Infusions of SKF-38393 or quinpirole were without effect on CS⁺ approach. However, post-session intra-amygdala infusions of 7-OH-DPAT enhanced selectively CS⁺ approach in a dose-dependent fashion. No dose of any drug affected CS⁻approach, US behaviours, or measures of extraneous behaviour. Subsequent acquisition of a novel conditioned instrumental response was also unaffected. Thus, the present data indicate a selective involvement of the D₃ dopamine receptor subtype in the modulation of stimulus-reward learning by the mesoamygdaloid dopamine projection. Received: 12 December 1996 / Final version: 9 April 1997     

2-甲基-7-亚甲基-1,4,6-三氧螺[4,4]壬烷与丙烯腈、丙烯酸甲酯的共聚合反应及竞聚率的测定

用高效液相色谱跟踪2-甲基-7-亚甲基-1,4,6-三氧螺[4,4]壬烷(MMTN)与丙烯腈(AN),丙烯酸甲酯(MA)的共聚合反应。根据Lowry-Meyer共聚积分方程式,采用插值法进行数据拟合测定单体的竞聚率。对于体系MMTN(M_1)-AN(M_2),r_1=0.048;r_2=0.213;MMTN(M_1)-MA(M_2)r_1=0.025,r_2=0.764。说明两组共聚体系均有较强的交替共聚趋势。     

红三叶总异黄酮对人乳腺癌MCF-7细胞增殖和凋亡的影响

目的研究红三叶总异黄酮对人乳腺癌MCF-7细胞的生长抑制和凋亡的诱导作用。方法在体外细胞培养下,采用不同质量浓度红三叶异黄酮和5-Fu处理MCF-7细胞,MTT法测定红三叶总异黄酮抑制MCF-7细胞增殖的量-效关系;TUNEL法、流式细胞术分析其细胞凋亡率和周期分布。结果红三叶总异黄酮对MCF-7细胞增殖的抑制作用随药物质量浓度提高和作用时间延长而更加明显,而在低质量浓度时却出现轻微促细胞增殖现象。TUNEL法、流式细胞术分析结果表明,红三叶总异黄酮能诱导MCF-7细胞凋亡,阻滞细胞于G2/M期,降低细胞增殖指数,且这种作用也存在剂量-效应关系。结论红三叶总异黄酮可抑制MCF-7细胞增殖并诱导其凋亡,具有抗肿瘤作用。     

B组轮状病毒WH-2株vp7基因的原核表达与抗体的制备

目的：在大肠杆菌中表达人B组轮状病毒WH-2株VP7蛋白并制备其兔抗血清。方法：根据B组轮状病毒（GBRV）WH-2株vp7基因的全序列设计引物,用PCR的方法扩增得到vp7基因的编码区。将其克隆到原核GST融合表达载体pGEX-KG内,转化大肠杆菌E.coliDH5α,IPTG诱导表达人B组轮状病毒WH-2株VP7蛋白,经SDS-PAGE分离纯化表达的蛋白免疫新西兰兔,制备人B组轮状病毒WH-2株VP7蛋白抗血清。结果：经鉴定确认,vp7基因以正确的方式插入到载体中,此重组表达载体经IPTG诱导后,可表达相对分子量为53.4 kDa的GST-VP7融合蛋白。制备的抗血清经同样诱导表达的表达载体pGEX-KG表达产物吸收后1：500倍稀释后用Western Blot分析,与53.4 kDa的GST-VP7融合蛋白获得特异性显色信号。结论：人B组轮状病毒WH-2株VP7蛋白成功在大肠杆菌中GST融合表达,所表达的蛋白和制备的抗体不但为研究结构与功能提供了物质基础,也为GBRV所引起的疾病预防、诊断和治疗等流行病学研究和临床诊断奠定了基础,具有重要实际应用价值。     

人白细胞介素7基因克隆及其真核表达载体的构建

目的：构建人白细胞介素7（hIL-7）的真核表达载体。方法：从人脾脏组织的总RNA中，用RT－PCR方法扩增出编码成熟hIL-7的cDNA，将其克隆于pMD18-T质粒中，并进行序列测定。再将hIL-7cDNA以正义及反义插入真核、原核双重表达载体pBK-CMV质粒，转化至大肠杆菌DH5α。最后将表达的lacz-hIL-7重组蛋白行SDS－PAGE电泳，并作考马斯亮蓝染色分析，western blot鉴定。结果：hIL-7序列测定结果与预期一致。pBK-CMV-hIL-7（正义插入）的无隆表达重组蛋白，western blot证实此蛋白为IL－7。结论：成功构建了hIL-7的真核表达载体，为进一步研究hIL-7的抗肿瘤作用创造了条件。     

青蒿素和青蒿琥酯对人乳腺癌MCF-7细胞的体外抑制作用比较研究

目的 对比研究青蒿素及其衍生物青蒿琥酯对人乳腺癌MCF—7细胞增殖的影响并探讨其作用机制。方法 采用体外培养的人乳腺癌MCF—7细胞株，利用SRB法测定青蒿素和青蒿琥酯对MCF—7细胞增殖的影响，FCM法测定细胞周期的变化，亚Gl期含量测定和DAN荧光染色法观察细胞凋亡。结果 10μmol/L青蒿素和lμmol/L青蒿琥酯能明显改变MCF—7细胞的细胞周期，使S期细胞显著减少，G0 Gl期细胞明显增加。青蒿素对MCF—7细胞增殖仅有微弱抑制作用，但其衍生物青蒿琥iB却有显著的抑制作用，IC50为0．3lμmol/L。同样，lμmol/L青蒿琥酷引起MCF—7细胞的凋亡和直接的细胞毒作用明显强于10μmol/L青蒿素的作用。结论 体外研究表明，对肿瘤细胞增殖的抑制青蒿琥酯比青蒿素作用强。     

Expression of the cell surface antigen detected by the monoclonal antibody A7 in pancreatic carcinoma cell lines

In a previous study, we used a murine monoclonal antibody, A7, against human colon carcinoma as a drug-carrier to treat colorectal cancer.¹ In the present study, we found that MAb A7 also reacted immunohistochemically with 73% of human pancreatic carcinoma cell lines, with the A7 antigen mainly being detected on the cell surface. However, the A7 antigen was found in only 9% of the spent media of these human pancreatic carcinoma cell lines by ELISA. On the other hand, the positive incidence of CA19-9, POA, ferritin, CEA, DU-PAN-2 and SLX in those spent media was 100%, 64%, 64%, 55%, 55% and 36%, respectively. These results suggest that the A7 antigen may only rarely be shed into the sera of pancreatic cancer patients, in which case MAb A7 could be a suitable drug-carrier in targeting chemotherapy for pancreatic cancer patients.     

人牙本质涎蛋白在COS-7细胞中的表达

目的 :构建人牙本质涎蛋白 (humandentinsialoprotein ,hDSP)真核表达载体 ,用瞬时系统表达目的基因。方法 :将hDSP全长基因定向克隆入真核表达质粒载体pcDNA3 ,构建pcDNA3 hDSP重组质粒 ,脂质体转染法转染COS 7细胞 ,48～ 72h收集细胞及培养上清 ,Westernblot和免疫组化检测表达产物。结果 :酶切鉴定表明重组表达载体构建成功 ;Westernblot检测显示在 60 0 0 0处出现一条清晰的特异性免疫阳性条带 ;免疫组化染色显示细胞胞质内有大量棕黄色颗粒 ,进一步证明该转染方法可行 ,转染效率较高。结论 :hDSP全长基因可以在COS 7细胞获得瞬时高效表达。     

何首乌提取物对人乳腺癌细胞脂肪酸合酶的抑制研究

目的 研究何首乌提取物对人乳腺癌MCF7细胞脂肪酸合酶(fatty acid synthase，FAS)的抑制作用。方法 MTT法测定人乳腺癌MCF7细胞增殖速度，采用超速离心技术部分纯化人乳腺癌MCF7细胞FAS。不同浓度何首乌提取物与FAS相互作用不同时间后，加入底物，用分光光度法观察何首鸟提取物对FAS的抑制作用。结果 何首鸟提取物对人乳腺癌MCF7细胞的增殖有一定的抑制作用。人乳腺癌MCF7细胞FAS被部分纯化，三种浓度何首乌提取物(0．1，0．5，1g／L)与FAS在催化前相互作用0、5和10min，对FAS活性的抑制率分别为24．60％、27．30％、and42．75％(0．1g／L)；43．50％、50．30％、and94．03％(O．5g／L)；98．60％、97．30％ and97．05％(1g／L)。结论 何首乌提取物对人乳腺癌MCF7细胞FAS具有抑制作用；作用强度既依赖于抑制剂浓度，又依赖于抑制剂与酶相互作用时间。     

8-硝基白杨素的合成及其抗肿瘤作用

目的　探讨 8-硝基白杨素的抗肿瘤活性。方法　荷Lewis肺癌雄性小鼠 5 0只 ,随机分为5组 (NS对照组 ,环磷酰胺组 ,低、中、高剂量 8-硝基白杨素组 ) ,每组 1 0只 ,均采用腹腔注射给药。末次给药 2 4h后 ,颈椎脱位处死小鼠 ,观察各组瘤重减轻情况及转移结节数。结果　低、中、高剂量 8-硝基白杨素均能明显抑制肿瘤的生长和肿瘤转移结节的数 (阳性药对照组和各处理组与对照组相比 ,P均<0 .0 1 ) ,高剂量 ( 5 0mg kg) 8-硝基白杨素与 1 0 0mg kg的环磷酰胺的抗肿瘤作用相当 (P >0 .0 5 )。结论　 8-硝基白杨素作为一种新黄酮衍生物 ,具有良好的抗肿瘤作用。