Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.6 (thromboplastin)
13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of a contraceptive with a low estrogen content (Neogynon), the estrogen component (50 mcg ethinyl estradiol) and consecutively the gestagen component (250 mcg D-Norgestrel) of the contraceptive on blood coagulation and fibrinolysis were studied in 8 women. Each treatment cycle was followed by a control cylce. At various times of the control and therapy cycles coagulation and fibrinolytic parameters were investigated. Statistical analyses were performed using multivariate 2-factorial analysis of variance. Plasminogen exhibited a statistically significant increase during the treatment with ethinyl estradiol and the combination of this steroid with D-norgestrel. No significant changes were found for all other parameters, including partial thromboplastin time, fibrinogen, Factors X, IX, VIII, Factor VIII-related antigen, antithrombin III, and fibrin(ogen)degradation products.
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PMID:[Blood coagulation and fibrinolysis in women receiving estrogen, gestagen and estrogen-gestagen-contraceptives (author's transl)]. 127 96

Researchers from Gainesville, Florida compared data on 20 women who were randomly assigned the triphasic oral contraceptive (OC) Triphasil (ethinyl estradiol and levonorgestrel) with data on 24 women who were randomly assigned the triphasic OC Ortho-Novum (ethinyl estradiol and norethindrone) and data on 8 women who were controls to evaluate these 2 triphasic OCs' effects on coagulation and anticoagulation factors. They measured these factors at baseline and 6 and 12 months after beginning OC use. Both OCs significantly reduced prothrombin time (Triphasil at 6 and 12 months, p.001; Ortho-Novum at 6 months, p01, and at 12 months, p.001). They also decreased partial thromboplastin time (Triphasil at 6 months, p.01), and at 12 months, p.001; Ortho-Novum at 6 months, p.01). Both OCs significantly increased Factor XII after 6 and 12 months (Triphasil p.001 and p.01 for controls and p.05 from baseline, respectively; Ortho Novum p.01). Ortho-Novum considerably increased fibrinogen antigen at 6 and 12 months (p.05 and p.001 from baseline and p.05 for controls, respectively) while Triphasil increased it only at 12 months (p.05). Platelet counts remained the same. Ortho-Novum markedly increased antithrombin III activity after 6 months (p.05). Even though neither OC changed antithrombin III antigen, they did significantly increase alpha-1-antitrypsin antigen and plasminogen antigen and activity at 6 and 12 months as well as alpha-2-antiplasmin antigen at 12 months. Ortho-Novum increased alpha-s-antiplasmin antigen at 12 months. No great differences in coagulation or anticoagulation factors existed between the OCs. The mean values were within reference ranges. These results showed that the OCs had the same, limited effects on hemostasis and changes in coagulation factors offset changes in anticoagulation factors.
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PMID:Changes in coagulation and anticoagulation in women taking low-dose triphasic oral contraceptives: a controlled comparative 12-month clinical trial. 144 74

Thirty-six young, healthy, nonsmoking women have been selected to check the effect of low-dose oral contraceptives on hemostasis. Two identical groups were treated by Marvelon (a monophasic oral contraceptive containing ethinyl estradiol and desogestrel) or Trigynon (a triphasic oral contraceptive containing ethinyl estradiol and levonorgestrel) for a 6-month period. In the absence, previously controlled, of substantial differences between the effects of each treatment on hemostasis, all the results were pooled at the third and sixth month of the study. The effects of oral contraceptive treatment were as follows: (1) platelet number, platelet aggregating ratio, and plasma beta-thromboglobulin level were not significantly altered, and (2) antithrombin III activity was not reduced despite a slight decrease or antigen concentration. The von Willebrand factor parameters, factor VIII:C, factor VII:C, and clottable fibrinogen were significantly increased. Plasminogen (activity and antigen concentrates) and alpha 2-antiplasmin levels were also significantly increased. Activated partial thromboplastin time and euglobulin lysis time measured after venous occlusion were significantly shortened. Although statistical analysis did not show dramatic changes in all these parameters, some individual extreme values were substantially altered. Therefore we believe that these later values are worthy of cautious consideration for weighing the role that hemostasis factors might play in individual thrombotic risk.
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PMID:Hemostasis profile in women taking low-dose oral contraceptives. 214 79

The frequent use of estrogen and progestin replacement for treatment in postmenopausal women makes assessment of its effect on the coagulation system of interest. Although the amount of estrogen used to achieve the desired therapeutic effect is lower than the lowest doses in oral contraception, the age and medical condition of this population may amplify any hormone-induced risk. The common impression is that postmenopausal replacement therapy does not increase risk for thromboembolic disease, but no large epidemiologic studies of estrogen replacement have addressed that question. In this randomized prospective study, we examined the effects of varying low doses of an estrogen-progestin preparation on the titers of clotting factors in postmenopausal women. The coagulation factors selected for investigation were among those that have been reported to be significantly altered in the plasma samples of high-dose estrogen users. There were no changes in prothrombin time, factor X, fibrinogen, factor VII, or fibrinopeptide A in any of the hormone-treated groups. Mild but significant shortening of the partial thromboplastin time and elevation of factor XII titer were noted in all treatment groups. The titer of antithrombin III was reduced in the group given 20 micrograms ethinyl estradiol, but not in the groups given 5 or 10 micrograms. The clinical significance of these changes is difficult to determine in postmenopausal women receiving sex hormone replacement. However, we have not noted any thromboembolic episodes in our volunteers after a 1-year follow-up period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Dose-dependent effects of postmenopausal estrogen and progestin on antithrombin III and factor XII. 333 25

Blood coagulation changes induced by sequential oral contraceptive (OC) therapy were studied. 112 healthy women volunteers were monitored over a 2-year period while on a regimen of sequential OC therapy (50 mcg ethinyl estradiol daily from Day 5 through 14 and 50 mcg ethinyl estradiol plus 1 mg morethindrone acetate on Day 15 through 25). The treated group showed marked increases toward hypercoagulability in the Hicks and Pitney thromboplastin generation time screening test at 3 and 9 months, Factor 5 at 9 months, Factor 8 at 3 and 9 months, and fibrinogen at 3 months. Decreases from base lines were seen in antiplasmins at 24 months and in alkaline phosphatase at all intervals (3, 9, and 24 months). It was suggested that the decrease in serum antiplasmin indicates a compensatory tesponse in the fibrinolytic system to the hyperactivity of the coagulation system.
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PMID:Progestational agents and blood coagulation. V. Changes induced by sequential oral contraceptive therapy. 427 88

A prospective investigation was initiated to assess the effect of a low-dose oral contraceptive containing 35 micrograms of ethinyl estradiol and 0.4 mg of norethindrone on blood coagulation and fibrinolysis. Twenty-four women were studied before, during, and after one year of treatment. Positive results included an accelerated activated partial thromboplastin time and an increase in fibrinolytic and anticoagulation factors as measured by alpha 1-antitrypsin antigen and plasminogen antigen and activity. Antithrombin III antigen was decreased but its activity was unaffected. There was no evidence of ongoing intravascular coagulation. No patient had a detectable thromboembolic event. In short, one year's usage of this low-dose oral contraceptive was not associated with a procoagulant hematologic profile.
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PMID:Low-dose oral contraceptive usage and coagulation. 616 2

The effect of Norplant, a subdermal contraceptive implant containing levonorgestrel, on blood coagulation factors was investigated in 47 healthy women. Coagulation parameters were also measured in 55 subjects who were taking combination type oral contraceptives (OCs) (either a pill containing 1 mg norethisterone and 50 mcg mestranol or a preparation containing 150 mcg levonorgestrel and 30 mcg ethinyl estradiol). Blood sampling was carried out at admission and after 1, 3, and 6 months of contraceptive use. Parameters measured included platelet count, prothrombin time, thrombin time, partial thromboplastin time with kaolin, clotting factors I, II, V, and VI-XIII, plasminogen, antithrombin III, alpha 1 antitrypsin, alpha 2 macroglobulin, and fibrinogen degradation products. Norplant users showed a lack of effect on the factors tested, except for factor VII activity, which was increased, and antithrombin III concentration, which was decreased after 3 months of use. In contrast, the combined OC users evidenced marked changes in platelet count, the screening tests, and most coagulation promoting factors. These changes became more pronounced after 6 months. Women taking the levonorgestrel-ethinyl estradiol OC evidenced less pronounced changes in some coagulation parameters than those taking the norethisterone-mestranol preparation; however, the high dropout rate among OC users limits the conclusions that can be drawn from these results. These results point to a relative lack of effect of Norplant implants on the blood coagulation-fibrinolytic system, presumably due to the absence of estrogen and the low dose of progestogen delivered to the body.
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PMID:Effect of levonorgestrel contraceptive implants, Norplant, on blood coagulation. 644 Jul 38

Female rats were given either ethinyl estradiol or norethindrone in conjunction with water or 5% ethanol. Hematological parameters measured included the prothrombin time (PT), partial thromboplastin time (APTT), fibrinogen (FIB), factors II, V, VII, VIII, X, and XII activity; plus the platelet count (PLT) and hematocrit (HCT). The data indicates that norethindrone together with water produces the greatest number of changes in clotting activity.
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PMID:Interaction between ethanol and contraceptive steroids on clotting activity in the rat. 685 68

Previous studies have documented an association between blood viscosity and risk factors for cardiovascular and thromboembolic disease. The present study assessed the impact of use of a low-dose, triphasic oral contraceptive (OC) containing ethinyl estradiol in combination with gestodene on the coagulation system, serum lipid metabolism, and blood viscosity. Enrolled were 10 OC users with no history of OC use before the study and 10 non-users. At 3 and 6 months after initiation of OC use, significant changes were recorded in partial thromboplastin time, fibrinogen, high density lipoprotein, and apolipoprotein A-1. Plasma viscosity was significantly increased during OC use, while whole blood viscosity and erythrocyte deformability remained unchanged. All alterations associated with OC treatment remained within the normal range of laboratory values, however. Thus, these findings suggest an absence of any significant OC effects on the hemostatic balance or lipid metabolism that might represent a risk factor for cardiovascular disease. Moreover, the measurement of blood viscosity may be a promising marker for monitoring thrombotic risk in women taking OCs given its apparent high sensitivity.
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PMID:Effect of low-dose oral triphasic contraceptives on blood viscosity, coagulation and lipid metabolism. 758 86

At Cagliari Hospital in Italy, the department of obstetrics and gynecology studied the efficacy and safety of a combined oral contraceptive (OC) containing 20 mcg of ethinyl estradiol and 150 mcg of desogestrel in 61 nonsmoking women aged 41-48. The women were followed for up to five years. After the second cycle of treatment, the mean length of the menstrual cycle and menses standardized at 26 and 4 days, respectively. By 12 months of OC treatment, the slight side effects either had disappeared or had significantly declined. No woman gained weight. Blood pressure did not change significantly. Lipid metabolism did not change significantly. There were only small insignificant increases in high and low density lipoprotein cholesterol, triglycerides, and apolipoproteins A. After 6, 12, and 24 months of OC treatment, sex hormone binding globulin levels increased significantly (1.83 vs. 3.6 mcg/dl; p 0.05). The OC did not significantly affect blood coagulation markers (fibrinogen, prothrombin time, partial thromboplastin time, antithrombin III, and fibrinopeptide A). It had no effect on fasting blood glucose and insulin levels and their response to the oral glucose tolerance test. The researchers conducted bone density measurements in the lumbar spine (L2-L4) of 37 women aged 45-48. The OC did not alter bone density. These results suggest that this low-estrogen-dose combined OC is a safe and effective contraceptive in perimenopausal women and has good acceptability and good cycle control without considerable side effects. The OC also exhibited the capability of further minimizing the thrombogenic effects of low-dose OCs.
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PMID:Contraception in older woman. 846 14


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