These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Heparin cofactor II levels are increased by the use of combined oral contraceptives.
    Author: Mackie IJ, Segal H, Burren T, Gallimore M, Walshe KJ, Robinson G, Machin SJ.
    Journal: Blood Coagul Fibrinolysis; 1990 Dec; 1(6):647-51. PubMed ID: 2133244.
    Abstract:
    Heparin cofactor II (HCII) was assayed by a microtitre amidolytic substrate technique. A linear response was obtained up to 1.5 U/ml and HCII levels were not affected by freezing and thawing the plasma. The assay was validated by comparing HCII and antithrombin III (AT III) levels in AT-III-deficient plasmas and samples from critically ill patients. Higher HCII levels were found in healthy normal women than in healthy normal men (means 1.16 and 0.97 U/ml, respectively, P less than 0.01). A significant increase in HCII levels from 0.86 to 1.10 U/ml (mean values) was seen in healthy normal women starting on combined oral contraceptive (COC) preparations (P less than 0.001). Increased HCII levels were maintained over a 6-month period, but fell towards normal 14 days after stopping COC, although they were still significantly higher than before starting COCs. The discrepancy in HCII level between normal men and women may be due to COC use. In clinical studies, different reference ranges should be used for men and women, and the need for careful questioning about the use of COCs is emphasized. Heparin cofactor II, a less well characterized heparin-dependent antithrombin factor than antithrombin III, was determined in 11 women before, during and after a 6 month trial of oral contraceptives, in 16 women aged 18-60, in 16 men aged 22-55, in 5 patients with known antithrombin III deficiency, and in a series of 16 patients in a critical care unit. The oral contraceptives used in the trial were Femodene (Schering, Burgess, Hill, U.K.) in 6 women and Marvelon (Organon, Cambridge, U.K.) in 5. The assay was an amidolytic microtiter method standardized against normal human serum. The assay was linear up to 1.5 U/ml, and HCII was not lost by repeated freezing and thawing. HCII levels were normal in patients with AT III deficiency, but ranged from 0.10-1.11 in intensive care patients. In normal subjects the mean HCII levels were 1.07 U/ml, and were significantly higher for women, 1.16, than for men, 0.97 U/ml. During intake of oral contraceptives, HCII rose significantly from 0.86 u/ml to 1.10 at cycle 1, 1.08 at cycle 3, and 1.19 at cycle 6. 2 weeks after stopping pills, the mean HCII level fell to 1.03. In contrast, AT III declined during pill cycles.
    [Abstract] [Full Text] [Related] [New Search]