NCl-H446细胞的125Ⅰ-[Tyr3]octreotide受体分析

目的探讨小细胞肺癌与[Tyr3]octreotide(TOC)的亲和力.方法用氯胺T方法标记的125Ⅰ-TOC作为配基,检测小细胞肺癌细胞株NCl-H446与其结合的受体位点数及亲和常数.结果氯胺T法标记的125Ⅰ-TOC经Sephadex G-10纯化后放化纯大于95%;受体分析显示NCI-H446表达的生长抑素受体多(Bmax=1.17×105受体位点/细胞),与125Ⅰ-TOC亲和力强(Kd=0.58nM).结论TOC的标记物可用于小细胞肺癌肿瘤的受体显像及放射治疗.     

美多巴与SCH 23390 在热环境中对大鼠体温的调节作用

观察美多巴和多巴胺Ｄ１受体拮抗剂ＳＣＨ２３３９０对大鼠体温的调节作用。实验大鼠预先分别给予两种药物后置于相同的热环境中,观察体温升高速率,同时用放射配基结合法检测纹状体中Ｄ１Ｒ的平衡解离常数和最大结合容量,用放射反应试剂盒测定纹状体中ｃＡＭＰ的浓度,用流式细胞仪检测纹状体细胞中钙调素的相对活性。结果表明：多巴胺受体激动剂美多巴能明显加快动物升温,而Ｄ１Ｒ拮抗剂ＳＣＨ２３３９０则明显阻升温,两种药物     

常压缺氧对大鼠肺组织肾上腺能受体分布的影响

本文利用自行标记的放射配基~(125)I CYP和~(125)I BE观察常压缺氧对大鼠肺组织β和α_1受体分布的影响,并用计算机图像处理系统半定量研究。正常大鼠肺组织β和α_1受体分布均以肺实质最多。支气管β受体多于肺血管,而肺血管α_1受体多于支气管。放射自显影的半定量结果表明:缺氧时肺内各种组织结构的β和α_1受体都有变化,肺血管β受体在缺氧2、4周时减少,α_1受休在缺氧1天和4周增加。这同我们用放射配基结合法测定的肺匀浆中β和α_1受体的变化是一致的。肺血管上β受体减少,α_1受体增加可加强缺氧性肺血管收缩。气道上的受体变化也会影响其对各种刺激的反应性,这些在缺氧性肺动脉高压的发生、发展中可能起着一定的作用。     

大鼠纹状体边缘区的多巴胺受体D1A参与了学习记忆功能

目的:研究多巴胺受体D1A在纹状体边缘区的分布及其是否参与了大鼠的学习记忆过程。方法:先用免疫组织化学方法观察多巴胺受体D1A在纹状体边缘区的分布,再向纹状体边缘区内立体定位微量注射多巴胺受体D1A拮抗剂SCH-23390(1%,0.1μl/侧)或等量的生理盐水,检测大鼠注射前后Y-迷宫结果的变化。结果:多巴胺受体D1A免疫组化阳性产物广泛分布于大脑皮层、海马、杏仁核、Meynert基核、下丘脑等处的胞体和突起上。在纹状体内,多巴胺受体D1A的阳性产物广泛而不均匀地分布于神经元的细胞核内,密度最大的区域在纹状体的尾内侧边缘。在纹状体尾内侧边缘,分布有多层密集平行排列的多巴胺受体D1A强阳性的椭圆形胞核,围绕苍白球外侧边缘,沿背腹方向呈带状分布,细胞核形态与位置和边缘区一致。行为实验证明,边缘区微量注射多巴胺受体D1A拮抗剂SCH-23390后,显著降低了大鼠的长期学习记忆能力。结论:大鼠脑纹状体边缘区神经元内存在多巴胺受体D1A,它们参与了成年SD大鼠的长期学习记忆功能。     

^18F-fallypride-新型多巴胺受体显像剂在脑神经疾病研究中的临床应用

^18F-Fallypride是一种新型安全的多巴胺D2受体PET显像剂,具有亲和力高、亲脂性适宜、半衰期短等特点,本文综述^18F-Fallypride用于精神分裂症、癫痫、抽动秽语综合征、兴奋剂成瘾性等的多巴胺D2/D3受体变化的研究。     

NCI-H446细胞的~(125)Ⅰ-[Tyr~3]octreotide受体分析

目的 :探讨小细胞肺癌与 [Tyr3 ]octreotide (TOC)的亲和力。方法 :用氯胺T方法标记的12 5I-TOC作为配基 ,检测小细胞肺癌细胞株NCl-H4 4 6与其结合的受体位点数及亲和常数。结果 :氯胺T法标记的12 5I-TOC经SephadexG - 10纯化后放化纯大于 95 % ;受体分析显示NCI-H4 4 6表达的生长抑素受体多 (Bmax =1 17× 10 5受体位点 /细胞 ) ,与12 5I-TOC亲和力强 (Kd =0 5 8nM)。结论 :TOC的标记物可用于小细胞肺癌肿瘤的受体显像及放射治疗。     

神经干细胞移植对帕金森病样模型大鼠的治疗作用

目的 观察大鼠神经干细胞(NSC)植入帕金森病(PD)模型大鼠的脑纹状体后的存活、分化及功能状态.方法 体外分离培养NSC,单克隆培养,免疫细胞化学检测多向分化潜能和特异性标记nestin.建立PD大鼠模型,纹状体内植入DAPI标记的NSC,检测6-羟基多巴胺(6-HHDA)诱发的旋转行为,荧光检测标记细胞的分布情况,免疫细胞化学和高效液相色谱检测细胞分化和神经递质含量.结果 培养的NSC表达nestin,具有自我更新和多向分化能力;NSC植入PD模型大鼠纹状体后大鼠诱导旋转行为显著改善(P＜0.05);NSC在脑内迁移,并在纹状体内形成少量酪胺酸羟化酶(TH)阳性细胞、纤维;植入后纹状体内多巴胺(DA)及其代谢产物含量上升,2个月时分别增加3.6倍和2.8倍,4个月时增加3.4倍和2.4倍(P＜0.01).结论 神经干细胞在体外大量扩增后植入PD脑内能长期存活并分化、分泌神经递质,从而部分改善PD症状.     

以间接碘标记法制备瘦素标记抗原的研究

目的:以间接碘标记法制备瘦素(leptin)的标记抗原(125I-leptin),建立瘦素的放射免疫分析(RIA)并用于临床。方法:先以氯胺T(ch-T)法标记对羟基苯丙酸琥珀酰亚胺脂(Bolton-hunter试剂,BH试剂)制备125I-BH,然后于冰浴中与leptin进行联结制备125I-leptin。结果:125I-leptin的放射性比活度为1 43MBq/μg,125I的总标记率为37 8%,用以建立的RIA各项技术指标均满足临床要求。结论:由于以间接法制备125I-leptin,减少了leptin与氧化剂、还原剂和放射性碘的接触,避免了对其抗原性的损伤,从而制备出具较高标记率和较高放射性比活度的125I-leptin。     

不同病程帕金森病大鼠纹状体多巴胺转运蛋白的动态变化

目的:观察不同病程帕金森病(PD)大鼠纹状体多巴胺转运蛋白(DAT)的动态变化,并探讨该变化与黒质酪氨酸羟化酶(TH)之间的关系。方法:采用双点注射6-OHDA至大鼠右侧黑质致密部和前脑内侧束,建立偏侧PD模型。建模后2周、4周、6周的PD大鼠分别尾静脉注射99mTc-TRODAT-1,1 h后取左右纹状体,以γ计数仪测定放射性计数,并计算单位质量的左、右放射性计数率以及左、右纹状体单位质量的放射性计数比值。同时取建模后2周、4周、6周PD大鼠黒质组织进行TH免疫染色,观察阳性细胞形态及分布。结果:PD大鼠毁损侧纹状体放射计数明显低于健侧,建模后2周、4周、6周PD大鼠DAT相对放射计数较健侧分别降低了16.8%、35.9%和50.1%(P0.05~0.001);不同病程PD大鼠毁损侧纹状体DAT的相对放射计数与TH阳性细胞数呈高度的正相关(P0.01,R=0.9,n=15)。结论:PD大鼠纹状体DAT含量随着病程的增加逐渐减少,99mTc-PRODAT-1的放射性分布能够较准确的反映突触前多巴胺能神经元的变化。     

放射性125碘标记阿莫西林研究临床分离MRSA青霉素结合蛋白

目的本文以放射性125碘标记阿莫西林研究临床分离MRSA青霉素结合蛋白(PBPs),探讨高耐药及低耐药不产酶MRSA青霉素结合蛋白的改变.方法用125Ⅰ-阿莫西林与ATCC25923、临床分离MRSA及MSSA结合,SDS-PAGE分离检测PBPs的改变.结果SDS-PAGE分离检测PBPs,高耐药株在78KDa处有放射性,低耐药株放射性低于敏感株.结论125Ⅰ-阿莫西林与MRSA结合降低,高耐药株产生低亲和力的PBP2a,低耐药株PBPs与阿莫西林结合下降.     

Somatostatin receptors in nasopharyngeal carcinoma

Somatostatin receptors (SS-Rs) are expressed in neuroendocrine tumour tissues where they can be targetted for diagnosis and therapy. This study investigated the presence of SS-Rs in nasopharyngeal carcinoma (NPC), a common cancer in South-East Asia. Nasopharynx biopsy specimens were obtained from 12 NPC patients and 5 patients without tumours. Somatostatin receptor autoradiography was performed using (125)I-labelled [Tyr(3)]-octreotide and (125)I-labelled [Leu(8), DTrp(22), Tyr(25)]-somatostatin-28 as radioligands. Of the 12 NPC samples 9 showed moderate to high expression of SS-Rs. These were of the sst(2) type, based on the rank order of potency of subtype-selective analogues. The 5 non-neoplastic samples, consisting primarily of granulomatous tissue, did not express measurable amounts of SS-Rs. This study demonstrates for the first time the presence of type 2 SS-R in NPC. These receptors may play a role in the management of NPC, as is the case for other somatostatin-expressing tumours.     

Comparative distribution of binding of the muscarinic receptor ligands pirenzepine,AF-DX 384, (R,R)-I-QNB and (R,S)-I-QNB to human brain

Quinuclidinyl benzilate (QNB) and its derivatives are being developed to investigate muscarinic receptor changes in vivo in Alzheimer's disease and dementia with Lewy bodies. This is the first study of [125I]-(R,R)-I-QNB and [125I]-(R,S)-I-QNB binding in vitro in human brain. We have compared the in vitro binding of the muscarinic ligands [3H]pirenzepine and [3H]AF-DX 384, which have selectivity for the M1 and M2/M4 receptor subtypes, respectively, to the binding of [125I]-(R,R)-I-QNB and [125I]-(R,S)-I-QNB. This will provide a guide to the interpretation of in vivo SPET images generated with [123I]-(R,R)-I-QNB and [123I]-(R,S)-I-QNB. Binding was investigated in striatum, globus pallidus, thalamus and cerebellum, and cingulate, insula, temporal and occipital cortical areas, which show different proportions of muscarinic receptor subtypes, in post-mortem brain from normal individuals. M1 receptors are of high density in cortex and striatum and are relatively low in the thalamus and cerebellum, while M4 receptors are mainly expressed in the striatum, and M2 receptors are most evident in the cerebellum and thalamus. [125I]-(R,R)-I-QNB and [125I]-(R,S)-I-QNB density distribution patterns were consistent with binding to both M1 and M4 receptors, with [125I]-(R,R)-I-QNB additionally binding to a non-cholinergic site not displaceable by atropine. This distribution can be exploited by in vivo imaging, developing ligands for both SPET and PET, to reveal muscarinic receptor changes in Alzheimer's disease and dementia with Lewy bodies during the disease process and following cholinergic therapy.     

Enkephalinase (EC 3.4.24.11) is highly localized to a striatonigral pathway in rat brain

Autoradiographic visualization of enkephalinase (membrane metalloendopeptidase, EC 3.4.24.11) in sagittal sections of rat brain using a 125I-labelled monoclonal antibody showed the presence of a dense immunoreactivity in a tract joining the striatum to the substantia nigra. Unilateral kainate injections into the striatum elicited a strong ipsilateral decrease in enkephalinase activity and immunoreactivity in both the injected area and substantia nigra, particularly its pars compacta. This demonstrates the presence of enkephalinase all along fibers of a striatonigral pathway.     

Interaction between herpes simplex type 1-induced Fc receptor and human and rabbit immunoglobulin G (IgG) domains.

Cells infected with herpes simplex virus type 1 (HSV-1) express a cell surface receptor able to bind to the Fc region of immunoglobulin G (IgG). The ability of HSV-1-infected cells to bind 125I-labelled human and rabbit IgG and IgG fragments was studied to localize the site of interaction to the C gamma 2 or C gamma 3 domains of IgG. 125I-labelled IgG and IgG Fc fragments consisting of C gamma 2 and C gamma 3 domains bound strongly to HSV-infected cells and did not bind to uninfected cells. In contrast, 125I-labelled F(ab')2, Facb [consisting of F(ab')2 and C gamma 2 domains] and pFc' (consisting of C gamma 3 domains) fragments did not bind to any of these cells. Unlabelled IgG and IgG Fc fragments inhibited the interaction between 125I-labelled rabbit IgG Fc and the HSV Fc receptor, whereas F(ab')2, Facb and pFc' fragments failed to inhibit this interaction. These data indicate that the HSV Fc receptor requires both the C gamma 2 and C gamma 3 domains for interaction with the IgG molecule analogous to the known interaction of protein A of Staphylococcus aureus, the Fc binding proteins of Group A, C and G streptococci, and certain human rheumatoid factors.     

大鼠纹状体边缘区内5-HT_(2A)受体的分布──原位杂交和免疫组织化学研究

已知纹状体边缘区有密集的 5 -HT纤维及终末分布。为了观察 5 -HT2 A受体 m RNA是否在大鼠纹状体边缘区表达 ,从基因分子水平和细胞水平进一步证明大鼠纹状体边缘区能否合成 5 -HT2 A受体 ,用地高辛标记的寡核苷酸探针进行原位杂交 ,研究了大鼠纹状体边缘区的 5 -HT2 A受体 m RNA的表达及分布。原位杂交结果发现 5 -HT2 A受体 m RNA阳性杂交信号在纹状体的分布不均匀 ,尾壳核只有少量中等大小的阳性胞体 ,苍白球也只有少量较大的阳性胞体 ,而在尾壳核和苍白球之间的边缘区部位则可见到许多中等大小的梭形阳性神经元胞体 ,并呈现密集的带状分布。免疫组织化学结果观察到 5 -HT受体阳性神经元胞体在纹状体的分布与原位杂交结果一致。本实验结果推测 ,大鼠纹状体边缘区神经元可以合成 5 -HT2 A受体 ,具有接受和整合 5 -HT神经递质的功能     

大鼠伏核、杏仁核、中脑导水管周围灰质内的CCK受体为CCK-B型受体:受体放射自显影分析

本工作用受体激动剂~(125)I-Bolton Hunter-CCK-8(~(125)I-BH-CCK)、CCK-A受体拮抗剂Devazepide、CCK-B受体拮抗剂L-365,260与脑组织切片共同孵育,以确定大鼠伏核、杏仁核、中脑导水管周围灰质等脑区内CCK受体的类型。结果显示:1μM未标记的CCK-8与~(125)I-BH-CCK及脑组织切片共同孵育,可完全竞争标记配体与受体的结合,说明这种结合是特异性的。30μM Devazepide可抑制脚间核处受体与标记配体的结合,但不能抑制伏核、杏仁核、中脑导水管周围灰质、大脑皮质及脊髓内受体与标记配体的结合;当剂量增大到90μM时,也只产生部分抑制。而用L-365,260只需90μM即可完全竞争伏核、杏仁核、中脑导水管周围灰质、大脑皮质及脊髓内受体与标记配体的结合。以上结果提示:脚间核部位的CCK受体为CCK-A受体;伏核、杏仁核、中脑导水管周围皮质、大脑皮质及脊髓内的CCK受体为CCK-B受体。     

Differential nicotinic receptor expression in monkey basal ganglia: effects of nigrostriatal damage

Our previous work showed that there were marked declines in (125)I-alpha-conotoxin MII labeled nicotinic receptors in monkey basal ganglia after nigrostriatal damage, findings that suggest alpha3/alpha6 containing nicotinic receptors sites may be of relevance to Parkinson's disease. We now investigate whether there are differential changes in the distribution pattern of nicotinic receptor subtypes in the basal ganglia in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned animals compared to controls to better understand the changes occurring with nigrostriatal damage. To approach this we used (125)I-alpha-conotoxin MII, a marker for alpha3/alpha6 nicotinic receptors, and (125)I-epibatidine, a ligand that labels multiple nicotinic subtypes.The results demonstrate that there were medial to lateral gradients in nicotinic receptor distribution in control striatum, as well as ventromedial to dorsolateral gradients in the substantia nigra, which resembled those of the dopamine transporter in these same brain regions. Treatment with MPTP, a neurotoxin that selectively destroys dopaminergic nigrostriatal neurons, led to a relatively uniform decrease in nicotinic receptor sites in the striatum, but a differential effect in the substantia nigra with significantly greater declines in the ventrolateral portion. Competition analysis in the striatum showed that alpha-conotoxin MII sensitive sites were primarily affected after lesioning, whereas multiple nicotinic receptor populations were decreased in the substantia nigra.From these data we suggest that in the striatum alpha3/alpha6 nicotinic receptors are primarily localized on dopaminergic nerve terminals, while multiple nicotinic receptor subtypes are present on dopaminergic cell bodies in the substantia nigra. Thus, if activation of striatal nicotinic receptors is key in the regulation of basal ganglia function, alpha3/alpha6-directed nicotinic receptor ligands may be more relevant for Parkinson's disease therapy. However, nicotinic receptor ligands with a broader specificity may be more important if receptors in the substantia nigra play a dominant role in controlling nigrostriatal activity.     

Muscarinic receptors in basal ganglia in dementia with Lewy bodies,Parkinson's disease and Alzheimer's disease

Derivatives of the muscarinic antagonist 3-quinuclidinyl-4-iodobenzilate (QNB), particularly [123I]-(R,R)-I-QNB, are currently being assessed as in vivo ligands to monitor muscarinic receptors in Alzheimer's disease (AD) and dementia with Lewy bodies (DLB), relating changes to disease symptoms and to treatment response with cholinergic medication. To assist in the evaluation of in vivo binding, muscarinic receptor density in post-mortem human brain was measured by autoradiography with [125I]-(R,R)-I-QNB and [125I]-(R,S)-I-QNB and compared to M1 ([3H]pirenzepine) and M2 and M4 ([3H]AF-DX 384) receptor binding. Binding was calculated in tissue containing striatum, globus pallidus (GPe), claustrum, and cingulate and insula cortex, in cases of AD, DLB, Parkinson's disease (PD) and normal elderly controls. Pirenzepine, AF-DX 384 and (R,S)-I-QNB binding in the striatum correlated positively with increased Alzheimer-type pathology, and AF-DX 384 and (R,R)-I-QNB cortical binding correlated positively with increased Lewy body (LB) pathology; however, striatal pirenzepine binding correlated negatively with cortical LB pathology. M1 receptors were significantly reduced in striatum in DLB compared to AD, PD, and controls and there was a significant correlation between M1 and dopamine D2 receptor densities. [3H]AF-DX 384 binding was higher in the striatum and GPe in AD. Binding of [125I]-(R,R)-I-QNB, which may reflect increased muscarinic M4 receptors, was higher in cortex and claustrum in DLB and AD. [125I]-(R,S)-I-QNB binding was higher in the GPe in AD. Low M1 and D2 receptors in DLB imply altered regulation of the striatal projection neurons which express these receptors. Low density of striatal M1 receptors may relate to the extent of movement disorder in DLB, and to a reduced risk of parkinsonism with acetylcholinesterase inhibition.     

Endocytosis of a mannose-terminated glycoprotein and formaldehyde-treated human serum albumin in liver and kidney cells from fish (Salmo alpinus L.)

The uptake and degradation of a mannose-terminated glycoprotein, yeast invertase, in char (Salmo alpinus L.) tissue was studied after intravenously injection of the 125I-labelled protein. 125I-labelled formaldehyde-treated human serum albumin (fHSA) and native HSA was also injected for comparison. Labelled invertase was rapidly cleared from blood and at about the same rate as labelled fHSA (at 8 degrees C). Approximately 50% of the initial concentration remained in blood 15 min after the injection of the ligands. Acid soluble degradation products appeared in the circulation about 60 min after the injection of the proteins. 125I-labelled invertase was recovered in the liver, pronephros and kidney. The clearance of labelled invertase from blood and the uptake in the organs were inhibited by co-injection of excess unlabelled invertase. fHSA was taken up in the pronephros and kidney tissue, while HSA was not taken up in any organs. In vitro degradation of the labelled ligands was studied in isolated pronephros cells, which had taken up the proteins in vivo. The degradation of invertase in isolated cells was partly inhibited by ammonium chloride. Ammonium chloride and chloroquine inhibited degradation of fHSA, but not leupeptin. These results together suggest that invertase and fHSA were taken up in the organs described by the receptor-mediated endocytosis. The degradation was partly or wholly lysosomal.