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Catalog #38-KAPF1991SpeciesHumanRegulatory StatusResearch Use Only. Not for Use in Diagnostic Procedures.Product DistributionAvailable WorldwideRange0-40 pg/mLSensitivity1.9 pg/mLSizes96 WellsSample TypesSerumIncubation Time2 hrIncubation Time2 hr 40 minSample Size10µLInstructions for UseClick here to viewSafety Data SheetClick here to view - Additional Information
- Additional Information
Nearly all circulating 25-OH Vitamin D in serum is bound to Vitamin D Binding Protein (88%) and Albumin (12%). Vitamin D Binding Protein (DBP) is a major component of serum, with a concentration of 250-400 mg/L of serum. Only a small portion, about 2%, of the Vitamin D binding sites of DBP is occupied. A very small fraction, approximately 0.04% of the 25(OH)Vitamin D, circulates in the free, non-protein bound form (1). The concentration of DBP is not constant and can be influenced by factors including obesity (2) pregnancy (3), the use of oral contraceptives (4) and liver disease (5). Variations in the concentration of DBP in serum will affect the unbound fraction 25-OH Vitamin D. For thyroid and steroid hormones it has been shown that their in vivo physiological activity correlates better with the free, non-protein bound fraction, than with the total concentration of the hormone in plasma. In such conditions the measurement of the concentration of the free circulating hormone provides more physiologically relevant information. This notion is known as the “free hormone hypothesis” (6). Particularly in situations in which the level of binding proteins is elevated or decreased, the measurement of total circulating hormone may lead to a wrong diagnosis. The bioavailability of 25-OH Vitamin D may be more complex, since it is a precursor that is metabolized in the kidney to the active 1,25(OH)2 Vitamin D. However, literature data suggest a role for the measurement of free 25-OH Vitamin D (7-10). The 25-OH Free Vitamin D ELISA makes it possible to measure the concentration of freely circulating 25-OH Free Vitamin D ELISA in serum.
References
Kane et al (2013) Vitamin D3 effects on lipids differ in statin and nonstatin treated humans: superiority of free 25-OH D levels in detecting relationships. J ClinEndocrinMetab. 98(11):4400-9.
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2、对的,封闭血清一般建议与二抗来源一致。
血清封闭:组织切片上有剩余的位点可以与一抗非特异性结合,造成后续结果的假阳性;封闭血清一般是和二抗同一来源的,血清中动物自身的抗体,预先能和组织中有交叉反应的位点发生结合;也可以用小牛血清、BSA、羊血清等,但不能与一抗来源一致。
如果你自己用,所用的配方什么的都是书本上的,而且封闭后将孔封好,估计可以放上一个月左右.
并且不同的方法,包被的蛋白不一样,稳定性也不一样.抗体相对来说会更稳定些.如果是一些虽的蛋白,那就难说,一个月都不一定
2.-20度甲醇固定20分钟后,自然、干燥 10分钟
3.PBS洗净:3min*3
4.1%Triton:25min-30min.配成50ultriton+5mlpBS
5.PBS洗净:2*5min
6.羊血清封闭:37度,20分钟
7.一抗,4度过夜,一般要大于18小时或者37度 1-2小时
8.4度 PBS洗净,3min*5次
9.二抗 37度小于一小时
参考见解:只是固定方法不同。细胞固定用甲醇,切片固定用多聚甲醛,而染色方法是一样的。
2、问:近期要做免疫荧光双标,不知哪位有免疫荧光双标技术的详细步骤及其注意事项?
参考见解:我正在做冰冻组织切片的免疫荧光双染。我的经验是:
(1)选取一抗时要来源于两种不同的动物,我用的是来源于rabbit和rat的抗体,二抗则是不同荧光信号标记的,我用的是donkey anti-rabbit-FITC(绿)和donkey anti-rat-Tex-Red(红)。
(2)我的做法是两种一抗(CHI抗体)同时孵育,然后两种二抗同时孵育。抗体浓度、孵育时间要仔细摸索,我感觉一抗4度孵育过夜比较好,背景比较清晰。
(3)我的阳性对照用的是阳性组织切片,阴性对照则分别是家兔和大鼠的IgG,荧光标记物对照是PBS+荧光标记物。
(4)封闭血清与二抗来源动物一致,我用的是10%的正常donkey血清。
(5)其余步骤同一般免疫荧光单标操作。
3、问:本人拟做Brdu标记神经干细胞免疫荧光,二抗为FITC标记,想请教各位大侠:
(1)抗体分装和荧光显微镜观察时是否一定要在暗室中进行?
(2)封片时是否用甘油缓冲液即可,还是用甘油和0.5mmol/L pH9.0-9.5的碳酸氢盐缓冲液等量混合封片?
(3)免疫酶染色中的3%过氧化氢及2N盐酸是否还需要用?
参考见解:
(1)你的二抗是用FITC标记的,为避免荧光分解,分装及荧光显微镜观察时均要避光;
(2)封片最好用甘油加0.5mmol/L pH9.0-9.5的碳酸氢盐缓冲液,后者能使玻片透明;
(3)关于免疫酶染色,如果是用过氧化物酶做标记,就必须用3%H2O2以去除内源性过氧化物酶;2N盐酸需要使用,目的是使DNA变性,让Brdu抗体能够充分地与已经掺入的Brdu结合。
4、问:做间接法免疫荧光染色,如何设置对照?
参考见解:最好是同一视野在未用荧光激发下进行对照,看是否非特异性染色。
(1)空白对照:如果你做的是石蜡切片免疫组化,这个对照必须有,目的是看自发荧光,脱蜡后直接在荧光显微镜下观察。
(2)阴性对照:标本直接滴加二抗,呈阴性反应。
(3)抗原对照:标本加同种动物的未免疫血清,以PBS冲洗后,在加抗免疫球蛋白荧光抗体。因未免疫动物的血清中无特异性抗体,应呈阴性反应。
5、问:我做乳腺组织的免疫荧光染色,结果用激光共聚焦显微镜看很好:有阳性信号,阴性对照组也没有荧光,但是拿到荧光显微镜下看,我的阴性对照组一片绿,像非特异性染色,到底哪个结果才是真实的呢?
参考见解:激光共聚焦显微镜的分辨率比普通荧光显微镜要高的多,出现上述现象首先要排除荧光显微镜的问题,如是不是紫外灯泡寿命到期了或者别的原因,荧光显微镜没有问题,那就以共聚焦显微镜的结果为主。展开
血清的目的就是因为含有白蛋白和抗体,所以一举两得。不过不应该用AB型。这是人的血清。流式检测一般都是使用小鼠单克隆抗体,所以封闭的血清也应该是用种的小鼠血清。
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