Linked Life Data

3501619

Source:http://linkedlifedata.com/resource/pubmed/id/3501619

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1988-3-14
pubmed:abstractText
High molecular weight kininogen (HK), the cofactor of contact-activated plasma proteolysis, is currently assayed by coagulant or immunological methods. The former is limited by the need for rare, congenitally-deficient plasma and a high coefficient of variation (CV), and the latter, by failure to distinguish nonfunctional protein. The surface activation of factor XI requires HK as its cofactor to transport its zymogen form to a negatively-charged surface where it is converted to its enzymatic form by factor XIIa. Based on this principle, we developed an assay for HK using the chromogenic substrate pyroGlu-Pro-Arg-p-nitroanilide (S-2366, KabiVitrum), which is hydrolyzed by factor XIa. Plasma is first acidified to inactivate protease inhibitors. After neutralization and dilution, the plasma is incubated with an excess of factor XI, factor XIIa, and soybean trypsin inhibitor (to inactivate generated kallikrein), in the presence of a negatively-charged surface (kaolin) in order to form factor XIa. EDTA is included in the buffer to prevent calcium-dependent reactions. This activation process is stopped by adding corn trypsin inhibitor to inactivate the enzyme in this reaction, factor XIIa. Then, S-2366 is added and is hydrolyzed by the factor XIa that was formed. Since factor XI and factor XIIa are in excess of the concentration of HK in the diluted plasma, HK is the rate-limiting protein in this assay for the formation of factor XIa (after subtracting the small amount of factor XIa generated in the absence of HK). The assay is specific for HK, since no activity is detected in kininogen-deficient plasma, and when compared with the HK coagulant assay, r = 0.95 and slope = 0.95. The mean of 21 normal donors was 0.98 U/ml (range 0.68 - 1.28 U/ml) as compared with pooled, normal plasma. The CV for 1 U/ml HK for the chromogenic assay was 2% as compared with 9.5% for the coagulant assay. When purified reagents become commercially available, this assay could prove useful in clinical laboratories or intensive care units for monitoring the progression of various disease states in which contact activation occurs.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0049-3848
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
48
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
685-700
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
A new assay for high molecular weight kininogen in human plasma using a chromogenic substrate.
pubmed:affiliation
Temple University School of Medicine, Department of Medicine, Philadelphia, PA 19140.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't