Purified CTICorn trypsin inhibitor (CTI) is a small protein that is localized in the kernels of most species of corn. CTI is not only an inhibitor of trypsin, but is also a specific human factor XIIa inhibitor when tested in blood clotting experiments (1-6). The inhibitor forms a one-to-one complex with either trypsin or factor XIIa, and when added to plasma, prolongs the activated partial thromboplastin time without affecting the PT assay (6). The specificity for factor XIIa makes the inhibitor useful for the segregation and study of tissue factor (TF) dependent coagulation reactions (6).
The use of CTI to study TF-dependent reactions has been documented in literature (6, 8-10). Studies indicate that suppression of the contact pathway of coagulation is essential when attempting to perform TF-dependent assays in whole blood or plasma samples. The addition of CTI at the point of sample collection prevents activation of the contact pathway during subsequent sample processing steps, thus reducing in-vitro artifact. The most common use of CTI is associated with thrombin generation assays when attempting to work at low TF concentrations. HTI’s CTI product is performance tested for this specific application.
The protein is comprised of 112 amino acids which yields a calculated molecular weight of 12,028 (7). The calculated molecular weight and that which has been determined by sedimentation equilibrium analyses of the purified protein (12,500) are in good agreement (3). A comparison of the amino acid sequence of CTI to that of other trypsin or serine protease inhibitors reveals little or no similarities (7).
CTI is purified using a combination of published procedures (3,4). To begin the purification process, CTI is extracted from the kernels of fresh sweet corn into a physiologic buffer. The extract is then de-fatted using acetone, and the protein is further purified by employing gel filtration and ion-exchange chromatography. The final CTI preparation appears as a single band by SDS-PAGE analyses under both reducing and non-reducing conditions.
Preparations of CTI are tested for the ability to prolong the aPTT assay without affecting the PT assay. The specific activity of each lot of CTI is determined, and one unit is defined as the amount of CTI required to double the aPTT of normal human plasma.
Purified CTI is formulated in 20 mM Tris, 0.15 M NaCl, pH 7.4 and should be stored frozen at -20°C or colder.
Blood Collection TubesTo simplify the process of collecting samples with added CTI, HTI has developed blood collection tubes containing CTI. These tubes (our SCAT-27 line) simplify the process of conducting TF-dependent studies by allowing you to draw blood directly onto an anticoagulant containing CTI. You may choose to use our standard CTI/Citrate formulation (11mM Citrate, 50 ug/mL CTI) or you may create your own custom formulation. HTI’s blood collection tubes are not sterile and are manufactured and sold for research use only. Three standard sizes are available although custom sizes can be manufactured for you.
SCAT-27-4.5/5 - 5 mL tube
SCAT-27-2.7/5 - 3 mL tube
SCAT-27-1.8/5 - 2 mL tube
ebiomall.com
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、
Cell-Based ELISA
的优点：
Cell-Based ELISA
（基于细胞的
ELISA
）是一种全新的
ELISA
技术，有两个最突出的优点：
1.1
不需要抽提蛋白、包被微孔板：细胞直接在微孔板里培养，待检测的时候，将细胞固定在微孔板上并
进行通透处理即可。这样就避免了抽提蛋白时，由于客观和主观上引起样品的损失而导致实验结果在一定
程度上偏离了实际情况。
同时不用包被微孔板，
简化了实验流程，
有助于提高效率。
科研人员在一个
96
孔
酶联板上，便能检测目标细胞蛋白经刺激或抑制作用后的表现。由于省去抽提蛋白和裂解细胞的步骤，样
本的损失也能降到最低，比起其他普通的
ELISA
测定方法，这项全新的
ELISA
技术能更快速、更方便
地一次检测大量的细胞内蛋白。
1.2
可同时检测两种不同蛋白：
封闭后加入两种抗不同蛋白且来源于不同宿主的一抗，
然后再加入不同的
二抗，加入两种荧光底物，检测两个波长。同时检测两种蛋白的好处是显而易见的，可以减少工作量，此
外还可以满足一些特殊的实验需要，例如，需要测定某个蛋白的磷酸化比例，就需要测定磷酸化蛋白的数
量和总蛋白的数量，这两个测定在同一次实验进行，有助于消除实验误差，得到更为精确的实验结果。
2
、
Cell-Based ELISA
的两种技术：
某些公司发展了双通道
Cell-Based ELISA
技术；
双通道与单通道
Cell-based ELISA
比较：
双通道
cell-based ELISA
，顾名思义，即一次可以同时检测两种目的蛋白，
R&D Systems
提供的
Cell-based ELISA
就是双通道
cell-based ELISA
，原理略：（需要荧光检测方式和相应仪器）；
单通道
cell-based ELISA
，即一次只能检测一种目的蛋白，他和普通
ELISA
的主要区别在于样品处理过
程
3
、
cell-based ELISA
的应用：
该产品，最多发展起来的是用于检测磷酸化和非磷酸化蛋白的相对含量；
4
、有
cell-based ELISA
产品的公司：目前，多家
elisa
产品提供
商均
提供
cell
based
elisa
试剂盒，
如
Rnd
systems
，
raybiotech
，
ebioscience
，
millipore
等公司；
5
、如何自己进行
cell based elisa
实验？
事实上，根据单通道的
cell based elisa
原理，可以自己建立
cell based elisa
实验系统；
细胞加入培养板中；
加入刺激物或者抑制剂进行培养；
对细胞进行固定或者封闭；
加入第一抗体；
加入
HRP
结合的二抗（二抗的选择，同
western blot
）；
加入底物进行显色；
我做的是细胞因子的刺激和抑制某条通路后观察是否有影响，分组为空白组，空白+抑制剂，刺激组，刺激+抑制剂，最开始用的单因素方差分析，LSD-T和SNK-Q检验，但是同学说我这里面有两个处理因素，所以不能单因素方差分析，应该直接空白和空白+抑制，空白和刺激，刺激和刺激+抑制剂进行独立样本T检验，现在脑子是混乱的，拜托园子里的大神们帮我看看，感激不尽！！
支原体培养则是取样后在培养基上培养，看有多少支原体菌落会长出，是比较直观和可信的结果。
总体来讲，这两种检查手段可信度都较高，结合一起，不仅可以可靠的知道有无解脲支原体感染，还能知道感染是否严重。
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MaggotsFasterThanScalpelinWoundDebridement
December19,2011—Maggotdebridementtherapy(MDT)appearstobemoreeffectiveforwounddebridementcomparedwithconventionaltherapy,butonlyat1week;afterthattime,anothertypeofdressingshouldbeused,newresearchsuggests.
KristinaOpletalovà,MD,fromtheDepartmentofDermatology,UniversityofCaen,France,andcolleaguespublishedonlineDecember19intheArchivesofDermatology.
MedicalmaggotswereapprovedbytheUSFoodandDrugAdmiNISTrationasamedicaldeviceforwounddebridementin2004.Accordingtotheresearchers,useofmaggotsintreatingwoundsisassociatedwitheffectivewounddebridement,antibacterialeffects,andstimulationofwoundhealing.
However,theypointout,"[r]elativelyfewclinicalstudieshavebeenconductedandtheresultsarenotclear,partlyowingtomethodologicassessmentproblems."
InthecurrentProspective,randomizedcontrolled,phase3clinicaltrial,theresearcherssoughttodeterminetheefficacyofbaggedlarvaeonwounddebridementincomparisonwithconventionaltreatment.
TheprimaryobjectivewastocomparethemeanpercentageofsloughinwoundstreatedwithMDTwiththatofconventionaltreatmentatday15.Thestudyincluded119patientswithanonhealing,sloughywoundthatwas40cm2orsmallerandlessthan2cmdeep.Patientsalsohadananklebrachialindexof0.8orhigher.
Treatmentwasadministeredduringa2-weekhospitalstay.Conventionaltreatmentconsistedofsurgicaldebridement3timesaweekwithascalpel,withuseoftopicalanesthesia.TheMDTwasadministeredusinganencloseddressing(Vitapad,BioMondeLaboratories)containing80sterilemaggots.Atdischarge,aconventionaldressingwasapplied,andpatientswerefollowed-upatday30.
DebridementbyMDTwassignificantlyfasterthansurgicaldebridementduringthefirstweekoftreatment,reachingthesamelevelthecontrolgroupreachedatday15.NobenefitforMDTcomparedwithconventionaltreatmentinhealingrateswasobserved.Atday8,54.5%intheMDTgroupvs66.5%inthecontrolgroup(P=.04)hadevidenceofsloughandwoundhealing.However,byday15,themeanpercentageofsloughwas55.4%intheMDTgroupand53.8%inthecontrolgroup(P=.78).
"AthoughMDTshowsnosignificantbenefitatday15comparedwithconventionaltreatment,debridementbyMDTissignificantlyfasterandoccursduringthefirstweekoftreatment,"theresearchersconclude."Becausethereisnobenefitincontinuingthetreatmentafter1week,anothertypeofdressingshouldbeusedafter2or3applicationsofMDT."
Painscoresweresimilarandmildinbothgroups,althoughincontrasttoconventionaltreatment,MDTwasperformedwithouttopicalanesthesia.
Accordingtotheresearchers,noneofthepatientswerereticentaboutundergoingMDT."[A]crawlingsensationonthewoundwasrarelyandalmostequallynotedinbothgroups,revealingthatthesensationwassubjective,"Dr.Opletalovàandcolleaguespointout.
TwoquestionsregardingMDTremainunanswered,theauthorsnote."Candebridementbeimprovedusingmoremaggotsperdressing?Ifso,wouldthesedressingsbemorepainful?Furtherstudiesareneededtoanswerthesequestions."
ThestudywassupportedbygrantsfromtheClinicalResearchHospitalProgramandfromtheFrenchSocietyofDermatology.Theauthorshavedisclosednorelevantfinancialrelationships.
