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Assay of factor VII activity by two techniques: evidence for increased conversion of VII to alpha VIIa in hyperlipidaemia, with possible implications for ischaemic heart disease.
Br J Haematol. 1985 Feb; 59(2):249-58.BJ

Abstract

Factor VII was assayed in healthy adults and pregnant women by a coagulation method (VIIc) and a procedure (VIIt) based upon activation of factor X. Although VIIc and VIIt were highly correlated (r 0.8) they apparently measured different aspects of VII activity. This difference was related to plasma lipid concentrations. Plasma VIIc showed independent positive associations in vivo with VIIt, cholesterol and triglyceride concentrations, but was unaffected by in vitro adjustment of plasma lipoprotein concentrations. The difference between assays might be due to differing reactivities of VII. The VIIc assay measures VII in its in vivo proportions as the single-chain protein and fully active double-chain form (alpha VIIa). In VIIt, all VII is converted to alpha VIIa before measurement. Thus an increase in VIIc but not VIIt with increasing lipid concentrations reflects an increased proportion of VII as alpha VIIa, possibly secondary to activation of the contact system. This effect may explain at least part of the increased VIIc and normal VIIt in pregnancy, and the increased VIIc of hyperlipidaemias in general. The relative values of VIIc and VIIt are proposed as a measure of flux within the coagulation system, and as a measure of coagulability in hyperlipidaemia and other states.

Authors

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Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

3871629

Citation

Miller, G J., et al. "Assay of Factor VII Activity By Two Techniques: Evidence for Increased Conversion of VII to Alpha VIIa in Hyperlipidaemia, With Possible Implications for Ischaemic Heart Disease." British Journal of Haematology, vol. 59, no. 2, 1985, pp. 249-58.
Miller GJ, Walter SJ, Stirling Y, et al. Assay of factor VII activity by two techniques: evidence for increased conversion of VII to alpha VIIa in hyperlipidaemia, with possible implications for ischaemic heart disease. Br J Haematol. 1985;59(2):249-58.
Miller, G. J., Walter, S. J., Stirling, Y., Thompson, S. G., Esnouf, M. P., & Meade, T. W. (1985). Assay of factor VII activity by two techniques: evidence for increased conversion of VII to alpha VIIa in hyperlipidaemia, with possible implications for ischaemic heart disease. British Journal of Haematology, 59(2), 249-58.
Miller GJ, et al. Assay of Factor VII Activity By Two Techniques: Evidence for Increased Conversion of VII to Alpha VIIa in Hyperlipidaemia, With Possible Implications for Ischaemic Heart Disease. Br J Haematol. 1985;59(2):249-58. PubMed PMID: 3871629.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Assay of factor VII activity by two techniques: evidence for increased conversion of VII to alpha VIIa in hyperlipidaemia, with possible implications for ischaemic heart disease. AU - Miller,G J, AU - Walter,S J, AU - Stirling,Y, AU - Thompson,S G, AU - Esnouf,M P, AU - Meade,T W, PY - 1985/2/1/pubmed PY - 1985/2/1/medline PY - 1985/2/1/entrez SP - 249 EP - 58 JF - British journal of haematology JO - Br J Haematol VL - 59 IS - 2 N2 - Factor VII was assayed in healthy adults and pregnant women by a coagulation method (VIIc) and a procedure (VIIt) based upon activation of factor X. Although VIIc and VIIt were highly correlated (r 0.8) they apparently measured different aspects of VII activity. This difference was related to plasma lipid concentrations. Plasma VIIc showed independent positive associations in vivo with VIIt, cholesterol and triglyceride concentrations, but was unaffected by in vitro adjustment of plasma lipoprotein concentrations. The difference between assays might be due to differing reactivities of VII. The VIIc assay measures VII in its in vivo proportions as the single-chain protein and fully active double-chain form (alpha VIIa). In VIIt, all VII is converted to alpha VIIa before measurement. Thus an increase in VIIc but not VIIt with increasing lipid concentrations reflects an increased proportion of VII as alpha VIIa, possibly secondary to activation of the contact system. This effect may explain at least part of the increased VIIc and normal VIIt in pregnancy, and the increased VIIc of hyperlipidaemias in general. The relative values of VIIc and VIIt are proposed as a measure of flux within the coagulation system, and as a measure of coagulability in hyperlipidaemia and other states. SN - 0007-1048 UR - https://www.unboundmedicine.com/medline/citation/3871629/Assay_of_factor_VII_activity_by_two_techniques:_evidence_for_increased_conversion_of_VII_to_alpha_VIIa_in_hyperlipidaemia_with_possible_implications_for_ischaemic_heart_disease_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0007-1048&date=1985&volume=59&issue=2&spage=249 DB - PRIME DP - Unbound Medicine ER -