用多点放射配基结合分析法求解受体参数所需孵育时间的研究

对受体的放射配基结合实验中反应时间与配基浓度的关系进行了数学分析和实验研究,证明当其它条件固定时,反应达到平衡所需的时间是放射配基初始浓度的函数。一般是初始浓度越小,平衡时间越长;用多点放射配基结合分析法求解受体参数时．孵育时间应选择能使低浓度放射配基达到平衡的时间,对可能出现的“倒钩”现象进行了讨论。     

氚标舒必利放射配基结合分析法的建立

研究了氚标舒必利([~3H]-Sulpiride)与大鼠纹状体膜蛋白的结合特性,结果表明两者结合具有特异性、饱和性、可逆性和配体选择性,B_(max)=917.0±133.2pmol/g蛋白,K_d=5.17±1.13nmol/l;并对根据这一结合特性建立的[~3H]-Sulpiride放射配基结合分析法作为测定血中舒必利浓度的方法进行分析,该方法的线性范围是1—100nmol/l,灵敏度是49.25ng/l,批内、批间变异系数分别为3.35％和10.6％。     

M受体亚型放射配基结合－免疫沉淀分析方法的建立及考核

利用１％洋地黄皂甙溶解大鼠脑匀浆Ｍ受体，用非选择性配基３Ｈ－ＱＮＢ标记可溶性Ｍ受体，以自制的Ｍ１、Ｍ２亚型抗血清和固相二抗分别特异性地免疫沉淀相应的亚型，分析单一受体亚型。对方法进行了考核，包括受体的溶解效率、抗原抗体反应时间、抗血清稀释度、反应温度等对分析结果的影响。对大鼠脑Ｍ受体的试验表明，用两种亚型抗血清进行的免疫沉淀分析呈典型的单位点饱和曲线，抗体对配基与受体的结合反应无影响。     

~(125)I-心得静的标记及β-肾上腺素能受体的结合试验

本文报道了用生物作用最强的β-受体阻断剂(一)心得静作配基,用~(125)I标记制备高亲和力和高比活性的放射配基。     

人血清生长激素放射受体分析法

以妊娠兔肝细胞膜碎片为受体制剂,用乳过氧化物酶法或Iodogen法碘化标记人生长激素,建立生长激素放射受体分析法。本方法灵敏度为0.67±0.11ng/ml。用RRA和RIA两种方法同时对72例正常成人、102例肢端肥大症患者测定血清GH浓度,结果表明正常成人两种方法测定结果无显著差异(P>0.05),而肢端肥大症患者的RRA值相似文献   

血小板低密度脂蛋白受体测定方法的改进

应用改进的不连续密度梯度超离心法分离脂蛋白，Ｉｏｄｏｇｅｎ法标记密度脂蛋白，离心洗涤分离血小板，ＲＢＡ测定低密度脂蛋白受体的活性，根据质量作了定律计算Ｂｍａｘ和ＫＤ，结果表明此法简单，有效，实用。     

β-内啡肽、促肾上腺皮质激素、5-羟色胺和去甲肾上腺素对疼痛和针刺镇痛的影响

本工作采用化学毁损弓状核及摘除大鼠垂体、荧光分析及放射免疫测定等方法,观察到:(1)毁损弓状核后脑内β-内啡肽含量降低67%,针刺镇痛效应明显下降:将此种处理大鼠的垂体切除后,针效几乎消失,同时,电针后脑去甲肾上腺素含量明显高于电针对照组。(2)促肾上腺皮质激素不仅提高基础痛阈,增强针刺镇痛效应和吗啡镇痛效应,同时也加强中枢5-羟色胺能神经元系统的功能。(3)大鼠摘除垂体后,针效明显减弱,脑内5-羟色胺及其转换率均下降,补充ACTH后,针效基本恢复,脑内5-羟色胺含量及其转换率也显著上升。     

An experimental study on rewetting phenomena in transient conditions of bwrs

It is known that rod temperature rise after boiling transition (BT) is not excursive and that the peak cladding temperature (PCT) is suppressed by rewetting to return to nucleate boiling, even if BT occurs under severe conditions exceeding abnormal operational transients for a BWR. The purpose of this study is to develop and verify the rewetting correlation. The rewetting correlation was developed based on single rod data, as a function of quality, mass flux, pressure and heat flux. The transient thermal-hydraulic code used in the BWR design analysis (SCAT) with this rewetting correlation was compared with transient rod temperature result after the occurence of BT obtianed by the 8×8 and 4×4 rod bundle. It is concluded that the transient code with the developed rewetting correlation predicts the PCT conservatively, and the rewetting time well.     

Theoretical and experimental study on single-phase natural circulation under inclined conditions

The natural circulation reactor is widely used in marine environments where thermo-hydraulic performance is heavily affected by the heaving, pitching, and inclining of a ship. This paper theoretically and experimentally investigated steady-state single-phase natural circulation under inclined conditions. Results showed that energy transported by natural circulation was proportional to 1.5 times the power of the temperature difference between the hot leg and the cold leg. Furthermore, a parameter, k, was presented that revealed the comprehensive influence of working fluid properties, resistance characteristics, gravity fields, and loop configurations. k was treated as the criterion for the circulation ability of a loop and it also acted as the basis for evaluating and optimizing different designs. Analysis under the guidance of k was confirmed by a series of experiments performed on a symmetrical two-circuit loop. Both theoretical and experimental results showed that the inclination restrained overall circulation due to the decrease in average altitude difference between the steam generators and the electric heater. The disparity in branch circulations increased with the increase in the inclined angle. A loop design consisting of a large altitude difference and a small width was preferable to confine the influence of inclination. However, if the loop width was too small, it caused a severe reduction in the circulation ability for large angle inclinations.     

Radio-ligand receptor binding assay in vitro and animal biodistribution in vivo of 99Tcm-N-ethyl-N2S2-memantine as a potential NMDA receptor imaging agent

The pharmacologic characteristics of 99Tcm-N-ethyl-N2S2-memantine,an NMDA receptor imaging agent,was investigated.It was prepared by a one-step reaction from N-ethyl-N2S2-memantine.The affinity and specificity were determined by radio-ligand receptor binding assay(RRA).Biodistribution in vivo in mice was performed.The results showed that 99Tcm-N-ethyl-N2S2-memantine bound to a single site on NMDA receptor with a Kd of 584.32 nmol/L and a Bmax of 267.05 nmol/mg.A competitive analysis showed that such specific binding could be inhibited by specific inhibitors of NMDA receptor,such as ketamine and(+)-MK-801.The biodistribution exhibited rapid uptake and favorable retention in mice brains.The major radioactivity was metabolized by the hepatic system.A two-compartment model of C=4.49e-0.083t+1.42e-0.0016t was established,and the half life was 8.35 min in blood.In conclusion,the new radio-ligand 99Tcm-N-ethyl-N2S2-Memantine has a moderate affinity and specific binding to NMDA receptor,and can easily cross the blood-brain barrier(BBB).Therefore,it may be a potential NMDA receptor imaging agent.     

Selection of the experimental conditions for white-light SRIXE measurements

Synchrotron-radiation-induced X-ray emission has enormous potential as a technique for trace-element analysis. To fully utilize the many advantages of SRIXE measurements, one must optimize the experimental conditions. In this paper the problems associated with the selection of experimental conditions are discussed in theory. In addition, examples of experimental work done at the National Synchrotron Light Source at Brookhaven National Laboratory, USA are presented.     

用放射性受体结合分析法研究补肾填精中药对老年大鼠脑组织中神经递质受体的影响

用放射性受体结合分析法研究了补肾填精中药对雌、雄性老年大鼠脑组织中神经递质受体的影响。实验表明:雌、雄性老年大鼠大脑皮层组织中α_1和DA(多巴胺)受体的结合容量(R_1)有不同程度降低,补肾填精中药固真冲剂可明显增加老年大鼠大脑皮层组织中α_1和DA受体的R_1值,这一作用被认为可能对脑组织产生延缓衰老的作用。     

用放射配体结合法测定小鼠心肌M-胆硷受体

本文用~3H-QNB作特异结合配基,用简单灵敏的放射配体法测定鼠心肌M受体。经28000×g低温离心制备膜制剂,在2ml Na-K磷酸缓冲液(pH7.4)中含0.8mg膜蛋白,不同浓度~3H-QNB 37℃温育半小时,用国产79型滤膜分离结合与游离部份,用0.01μM QNB作测非特异结合用。对四批ICR纯种小鼠测得的K_D值为0.0918±0.0136nM。实验中用~3H-QNB测得结合曲线,用Scatchard、Hill及双倒数作图法求得K_D和B_~(max)值,还测定了非标记QNB取代50％时剂量、~5H-QNB的结合速度常数与解离速度常数及其t_(1/2)等参数。