首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
We have demonstrated that the nerve growth factor will interact with various acidic proteins apparently nonspecifically. When125I-labeled nerve growth factor at a concentration of 3.8×10–10 M is incubated with an acidic protein at 2 mg/ml (4.5×10–6–4.4×10–5 M), a complex is formed. This complex changes the isoelectric point of the125I-labeled nerve growth factor sufficiently so that the125I-labeled nerve growth factor migrates anomalously in polyacrylamide gel electrophoresis. The interaction between nerve growth factor and bovine serum albumin, which appears to be complex, may be the cause of the previously reported activation of the nerve growth factor when bovine serum albumin is present in a typical bioassay.A preliminary report of this work was presented at the American Society of Biological Chemists, 71st Annual Meeting, in June 1980.  相似文献   

2.
1. The number and distribution pattern of -adrenergic receptors in the brain have been reported to be species specific. The aim of the present study was to describe binding of the -adrenoceptor ligand [125I]iodocyanopindolol in the brain of the tree shrew (Tupaia belangeri), a species which provides an appropriate model for studies of psychosocial stress and its consequences on central nervous processes.2. 125I-Iodocyanopindolol (125ICYP) labeling revealed a high degree of nonspecific binding, which was due mainly to interactions of this ligand with serotonin binding sites. For a quantitative evaluation of 1- and 2-adrenoceptors, serotonin binding sites had to be blocked by 100 M 5HT.3. Binding of the radioligand to 1- and 2-adrenoceptors was characterized using the 1-specific antagonist CGP20712A and the 2-specific antagonist ICI118.551. 1-adrenoceptor binding is present in the whole brain, revealing low receptor numbers in most brain regions (up to 1.5 to 2.7 fmol/mg). A slight enrichment was observed in cortical areas (lateral orbital cortex: 4.0±0.7 fmol/mg) and in the cerebellar molecular layer (8.7±1.0 fmol/mg).4. Competition experiments demonstrated high- and low-affinity binding sites with considerable variations in K i values for CGP20712A, showing that various affinity states of 1-adrenoceptors are present in the brain (K i: 0.61 nM to 67.1 M). In the hippocampus, only low-affinity 1-adrenoceptors were detected (K i: 1.3±0.2 M). Since it is known that 125ICYP labels not only membrane bound but also internalized -adrenoceptors, it can be assumed that the large population of the low-affinity sites represents internalized receptors which may be abundant due to a high sequestration rate.5. High numbers of 2-adrenoceptors are present in only a few brain structures of tree shrews (external layer of the olfactory bulb, 15.8±2.0 fmol/mg; claustrum, 19.3±1.5 fmol/mg; anteroventral thalamic nucleus, 19.4±1.5 fmol/mg; cerebellar molecular layer, 55.0±4.3 fmol/mg). Also for this class of -adrenoceptors, high- and low-affinity binding sites for the 2-selective antagonist ICI118.551 were observed, indicating that 125ICYP labels membrane bound and internalized 2-adrenoceptors. Only in the cerebellar molecular layer was a high percentage of high-affinity 2-adrenoceptors detected (K i for ICI118.551 was 1.8±0.3 nM for 90% of the receptors).6. In conclusion, 1- and 2-adrenoceptor binding can be localized and quantified by in vitro receptor autoradiography in the brains of tree shrews when serotonergic binding sites are blocked. Modulatory effects of long-term psychosocial conflict on the central nervous -adrenoceptor system in male tree shrews are described in the following paper.  相似文献   

3.
《Life sciences》1994,56(5):PL97-PL102
Previous reports have demonstrated that β-endorphin stimulates the clonal growth of human small cell lung carcinoma (SCLC) cell lines. In this study, the human SCLC lines, NCI-H69, NCI-H345, and NCI-N417, were observed to be highly-enriched in saturable, high-affinity binding sites which are labeled by [125I]β-endorphin. In contrast to conventional opioid receptors, [125I]β-endorphin SCLC binding was insensitive to naloxone and other mu, delta, or kappa opioid ligands. Further analysis of the NCI-H69 cells demonstrated that specific (naloxone-insensitive) binding was dependent on receptor concentration, reversible, sensitive to sodium ion, but insensitive to the GTP analogue, Gpp(NH)p. These results suggest a role for naloxone-insensitive β-endorphin in modulating SCLC metabolism.  相似文献   

4.
盆腔恶性肿瘤复发并不少见,肿瘤复发意味着盆腔局部治疗失败.对于盆腔恶性肿瘤,临床上大多数采取根治性手术和/或者根治量的放疗来进行治疗,其往往伴有顽固性疼痛、严重出血、瘘管形成及复发的高风险;因此该类肿瘤的复发临床处理棘手,大多数采取姑息性治疗.本文将综述盆腔复发肿瘤的125I内放射介入治疗进展.  相似文献   

5.
用国产多聚肌苷酸和多聚胞嘧啶核苷酸(简称多聚[I]:多聚[c])制备成双链核糖核酸特异性抗血清,用环状沉淀和’H标记的番茄花叶病毒双链核糖核酸测得抗血清效价分别为1:128和1:6400。用免疫琼脂双扩散、对流免疫电泳和放射免疫测定可测定出多聚[I]:多聚[c]的最低浓度分别为391ng、12.2/ng和10pg/ml抗血清和酵母、TMV、P。X的单链核糖核酸、小牛胸腺DNA不反应。试验证明用国产多聚[I]:多聚[C]制备的抗血清,可有效地用于双链核糖核酸的免疫化学鉴定。由于在免疫双扩散和对流免疫电泳中抗血清能和微量双链核糖核酸反应并产生可见沉淀线,从而有可能利用这两种简便灵敏的方法测定病毒的双链RNA,单链RNA病毒的RF型RNA,以及双链RNA真菌病毒的筛选。  相似文献   

6.
Characteristic of [125I]-conotoxin (-CgTX) labeling using bifunctional cross linker (dithio bis[succinimidyl propionate]: DSP) was systematically investigated in crude membranes from chick whole brain. [125I]-CgTX specifically labeled 216 kDa as a main and 236 kDa as a minor bands in the crude membranes under non-reduced condition, but not labeled under reduced condition. We investigated the effect of various Ca channel antagonists on [125I]-CgTX labeling with DSP in detail, and found that there is a strong correlation between the effects of Ca channel antagonists on [125I]-CgTX labeling of the 216 kDa band and specific [125I]-CgTX binding. These results suggest that labeling of the 216 kDa band under non-reduced condition with [125I]-CgTX using DSP involves the specific binding sites of [125I]-CgTX, perhaps including one of the neuronal N-type Ca channel subunits in the crude membranes.  相似文献   

7.
α肾上腺受体在调节血管张力和反应性方面,可能行使重要的作用。血管α肾上腺受体的药物学特性,过去是通过血管的收缩,间接反应的,因此,对血管α肾上腺受体的生物化学特性及其调节作用仍不太清楚。近年来,由于放射性配基结合技术的迅速发展,改进了肾上腺受体的研究。已采用的氚标记α配基有[~3H]dihydroergocryptine、[~3H]yohimbine、[~3H]WB 4101。1981年Colucci等用放射性配基成功地测定了大鼠肠系膜动脉的α受体,发现它是α_1亚型。但由于氚标记的放射性配基相对特异性小、比放射性低、测定动脉平滑肌受体时需要大量的血管组织来制备膜受体,这对于一些小型实验动物,存在不少困难。最近,Tsujimoto等报道了一种新型的、高特异性的、有效的、同位素碘标记的α配基——[~(125)I]BE 2254。药理学实验说明,BE 2254对α_1受体有优先的抑制作用,用~(125)I标记的化合物,更增加了对α_1肾上腺受体  相似文献   

8.
油菜素甾酮是合成油菜素内酯的前体,它具有70%以上的油菜素内酯生物活性。油菜素甾酮的B环-6-酮基经与盐酸羧甲基羟胺反应后得到油菜素甾肟,当浓度为10μmol/L时用水稻叶片倾斜法其生物活性比对照增加60%以上;当浓度为2μmol/L时能促使黄瓜下胚轴伸长,比对照增加20%。用油菜素甾肟与油菜素内酯或油菜素甾酮一起处理黄化水稻幼苗,测得水稻叶片与叶鞘之间的倾斜角度介于它们单独处理之间。用氯胺-T法  相似文献   

9.
The Harderian glands are innervated by sympathetic fibers originating in the superior cervical ganglia. The aim of this study is to characterize the -adrenergic receptors in the rat Harderian gland. The characteristics of -adrenergic receptors were determined in crude membrane preparations from rat Harderian gland, using [125I]iodocyanopindolol ([125I]CYP) as radioligand. The binding of the ligand to the receptor is rapid, reversible, saturable, specific and dependent on time, temperature and membrane concentration. At 30 °C, stoichiometric data suggest the presence of one binding site with a Kd value of 0.29 nM and Bmax of 32 pmol/L. The interaction shows a high degree of specificity for -adrenergic agonists and blockers, as suggested by competitive displacement experiments with isoproterenol (IC50=19.1 nM), propranolol (IC50=28.1 nM), and norepinephrine (IC50=96.3 nM). Clonidine, yohimbine, methoxamine, and prazosin are ineffective at concentrations up to 1 M. In the other hand, binding of [125I]CYP by Harderian gland membranes exhibits day—night variations. Binding values are low during the daytime and increase progressively late in the evening to reach a maximum at 2200 h (2 h after the onset of dark period), but decreased to the end of the dark period (0600 h). In conclusion, the results presented in this paper show the functional and pharmacological characterization of -adrenergic receptors in the rat Harderian gland. This neurotransmitter may play a physiological role at this level regulating, at least, processes such as a thyroid hormone metabolism.  相似文献   

10.
研究白眉蝮蛇(Agkistrodon halys ussuriensis)毒精氨酸酯酶的代谢动力学,为临床应用提供依据。125I标记的精氨酸酯酶对大鼠一侧颈静脉给药,不同时间从另一测颈静脉取血。5h后处死动物,取各组织、尿液、胆汁和粪便,对各样本的放射性进行测定并拟合时间-放射性关系曲线。代谢动力学拟合曲线符合一室模型,其中生物半衰期T1/2为55.9min,K值为0.0124min-1。125I标记的精氨酸酯酶在体内各组织广泛分布,但有血脑屏障存在,肝、肾和尿液中的放射性比其它组织要高很多,主要通过肝脏降解,肾脏排泄。  相似文献   

11.
^125I标记单抗LC—I与肺腺癌细胞体内外结合特性的研究   总被引:1,自引:0,他引:1  
McAb LC-1 was derived from fusion of myeloma cells and murine spleen cells immunized with human lung adenocarcinoma SPC-A-1 cells. The immunoglobulin isotype of LC-1 belonged to IgM. LC-1 was direct against the common epitope of lung cancer. It not only reacted with small cell lung cancer but also with non small cell lung cancer. LC-1 was purified from ascitic fluid by euglobulin precipitation and Sephadex G-200 filtration chromatography, and was iodinated with Iodogen, the specific reactivity of 125I-labeled LC-1 was determined by comparing standard curve with self-displacement curve. The immunoreactive fraction of 125I-LC-1 was determined by its binding to excess of antigen. The RIA data were plotted in Scatchard-form as binding of SPC-A-1 cells to LC-1. The binding constant of LC-1 binding to SPC-A-1 was 4.8 x 10(8) M-1. The LC-1 binding sites on SPC-A-1 were 7.2 x 10(4) per cell. The RIA inhibition test showed that LC-1 and LAC-122 (another IgM isotype McAb reacted only with non small cell lung cancer) had no cross-reactivity. The treatment of SPC-A-1 cells by proteinase and sodium periodate inhibited LC-1 binding to these treated target cells by 39% and 66% respectively. These results suggested that the biochemical nature of antigen recognized by LC-1 was glycoprotein.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
油菜素甾酮(brassinosterone)是合成油菜素内酯(brassinolide)的前体,它具有70%以上的油菜素内酯生物活性。油菜素甾酮的B环-6-酮基经与盐酸羧甲基羟胺反应后得到油菜素甾肟,当浓度为10μmol/L时用水稻叶片倾斜法测得其生物活性比对照增加60%以上;当浓度为2μmol/L时能促使黄瓜下胚轴伸长,比对照增加20%。用油菜素甾肟与油菜素内酯或油菜素甾酮一起处理黄化水稻幼苗,测得水稻叶片与叶路之间的倾斜角度介于它们单独处理之间。用氯胺-T法制备125I-组胺,再与油菜素甾肟结合。先用黄瓜幼苗下胚轴伸长法初步筛选活性组份,再用水稻叶片倾斜法鉴定活性,表明Rf0.93处的组份能使水稻幼苗叶片的倾斜活性增加25%,其放射性比强为73.8GBq/mmol。  相似文献   

13.
^125I标记乙型肝炎病毒DNA探针的制备及应用   总被引:1,自引:0,他引:1  
  相似文献   

14.
15.
余茂耘  韦传宝 《生物学杂志》2007,24(2):32-33,53
研究白眉蝮蛇(Agkistrodon halys ussuriensis)毒精氨酸酯酶的代谢动力学,为临床应用提供依据。125I标记的精氨酸酯酶对大鼠一侧颈静脉给药,不同时间从另一测颈静脉取血。5h后处死动物,取各组织、尿液、胆汁和粪便,对各样本的放射性进行测定并拟合时间-放射性关系曲线。代谢动力学拟合曲线符合一室模型,其中生物半衰期T1/2为55.9min,K值为0.0124min-1。125I标记的精氨酸酯酶在体内各组织广泛分布,但有血脑屏障存在,肝、肾和尿液中的放射性比其它组织要高很多,主要通过肝脏降解,肾脏排泄。  相似文献   

16.
利用同位素示踪法研究了不同引入途径的125I和65Zn在大蟾蜍体内的吸收与分布。无论采用注射还是灌喂的方法,蟾蜍对125I的残留动态差别不大,都可分为快清除期和平台期,0~2d为快清除期,3~7d为平台期,经过了快清除期之后,残留的125I约为起始量的8%,并维持到实验结束。注射了65Zn后,0~7d的吸收动态曲线有所起伏,但波动很小,其波动范围为102.4%~114.48%。表明大部分的65Zn仍留在体内,几乎没有排出体外。注射65Zn的转移并不明显。但灌喂65Zn的动态变化则大些,而且转移明显。其活度曲线出现阶段性下降,有两个下降期,第一个下降期为4h~3d,第二个下降期为5~7d。说明灌喂组对65Zn的转移比注射组的活跃,但在实验的第7d残留率仍在60%以上。  相似文献   

17.
1. Stress is known to affect the functioning of the central noradrenergic system in a region-specific manner. The aim of the present investigation was to understand better the consequences of recurrent stressful experiences on central -adrenoceptors.2. Alterations in the central nervous -adrenoceptor system resulting from different periods of psychosocial stress (PSS) were analyzed in male tree shrews (Tupaia belangeri) which were submitted to subordination stress for varying time periods.3. In the first experiment, the whole number of -adrenoceptors was analyzed in the forebrains of subordinate animals and controls by in vitro autoradiography using 125I-iodocyanopindolol (125ICYP), while nonspecific binding of the radioligand to serotonin receptors was blocked with 100 M 5HT.4. PSS affects -adrenoceptors in a time-dependent manner. A decrease in receptor affinity occurred after just 21 days of PSS in cortical areas and in the hippocampus, indicating stress effects on the conformation of -adrenoceptors. After 30 days of PSS,the numbers of -adrenoceptors were significantly decreased in several cortical regions and in the olfactory area.5. In the second experiment, we investigated the influence of PSS on both 1- and 2-adrenoceptors separately. 125ICYP binding was quantified in the presence of either ICI188.551 to block 2-adrenoceptors or in the presence of CGP20712A to block 1-adrenoceptors.6. After 2, 10, 21,and 28 days of PSS, it become apparent that the two -adrenoceptor subtypes are regulated independently. 1-Adrenoceptors were transiently down-regulated after 2 days of PSS in the prefrontal cortex and in the olfactory area and were decreased after 28 days of PSS in the parietal cortex and the hippocampus. A transient up-regulation of 1-adrenoceptors occurred in the pulvinar nucleus after 10 days of PSS. 2-Adrenoceptors were transiently down-regulated after 2 days of PSS in the prefrontal cortex and up-regulated in the pulvinar nucleus after 28 days of PSS.7. These data demonstrate that chronic psychosocial stress in subordinate tree shrews leads to time-dependent changes in the central nervous -adrenoceptors system.8. The high regional variability in stress-induced -adrenoceptor regulation is supposed to be due to the complex mechanisms of intracellular -adrenoceptor sequestration, which includes down-regulation and/or reinsertion of receptors into the plasma membrane. These mechanisms may be important components of the regulatory apparatus which enables the individual to adapt to situations of recurrent stressful experiences by balancing the central nervous adrenoceptor number.  相似文献   

18.
Radioiodinated (+)−3-Iodo-MK-801 is a high affinity radioligand for the N-methyl-d-aspartate (NMDA) receptor-channel complex. We have demonstrated in vivo localization in the CNS of rat which is stereoselective and blocked by coinjection of unlabeled MK-801. Autoradiography indicates localization in vivo which is in concordance with in vitro autoradiographic studies. These results indicate that radioiodinated (+)−3-Iodo-MK-801 is a useful probe for in vitro and in vivo autoradiographic studies and suggest that radioligands for the NMDA receptor may be developed which will provide in vivo images of receptor distribution in man.  相似文献   

19.
20.
谈宗国  毛世华  刘洁  章伟芬  熊辉 《生物磁学》2013,(26):5127-5129,5142
目的:研究复发性妇科恶性肿瘤腹腔镜下病灶切除术^125I粒子植入后血清CA125水平变化及临床意义。方法:选取2012年4月-2013年4月来我院就诊的40例复发妇科恶性肿瘤患者,平均分为实验组和对照组,每组各20例。实验组20例行腹腔镜下切除病灶并进行^125I粒子植入治疗,对照组20例仅行腹腔镜切除病灶治疗。监测术后6个月内患者血清CA125的变化情况。结果:术后随访的6个月内,实验组的血清CA125水平明显降低,术后3个月降低至正常水平共有14例(75%);术后随访的6个月内,对照组血清CA125水平降低后逐步升高,术后3个月降低至正常水平共有3例(15%),两组比较有统计学意义(P〈0.05);同时实验组的2a肿瘤生存率为20%,对照组为80%,两组比较有统计学意义(P〈0.05)。结论:复发性妇科恶性肿瘤腹腔镜下病灶切除术125I粒子植入后血清CA125水平显著降低,该法是评估肿瘤治疗疗效的有效方法。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号