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 effect of 5 years' use of Norplant on blood clotting factors was assessed in 97 Singaporean women. The subjects were healthy, non-smoking non-alcohol drinking and non-lactating. Blood was sampled at 6, 12, 18, 24, 36, 48 and 60 months, after an overnight fast, and resting 30 minutes before venipuncture. Hemoglobin and hematocrit increased 10% in the 1st year (p0.001), fell for the next 2 years, reaching pre-insertion levels by 3 years, then increased 10% for the last 2 years. There was a significant shortening of the prothrombin time (PT) throughout the 5 years, and of activated partial thromboplastin time (APTT) for 3 years. Vitamin K-dependent Factors II, V, VII, decreased throughout the 5 years, and fibrinolytic activity decreased at 2 and 4 years of use. Fibrinogen increased at the end of the 1st year only. Platelet numbers rose 25.6% to 43.4%, and platelet aggregation to both ADP and collagen increased throughout the 5 year period. Alpha2-macroglobulin and antithrombin III antigen levels were heightened for 4 years. Most of the observed changes were different from those seen in oral contraceptive users, except for alterations in platelet function. While some of the measured clotting factors were significantly different, none were of any clinical significance, nor were these women in a state of hypercoagulation.
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PMID:Effect of long-term use of Norplant implants on haemostatic function. 138 Sep 4

A longitudinal study of hemostatic function was carried out on 100 Singaporean acceptors using Norplant-2 rods for contraception. The results at the end of three years indicate a possible increased predisposition to thrombosis, as evidenced by significant increases in platelet count and aggregability. The prothrombin time (PT) and activated partial thromboplastin time (APTT) continued to remain shortened at the end of three years of use. There was also a general fall in most of the vitamin K coagulation factors. There is thus still an indication of a possible enhanced potential for hypercoagulation at the end of three years of Norplant-2 rod use.
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PMID:A three-year evaluation of hemostatic function in Singaporean Norplant-2 rod acceptors. 211 46

A longitudinal study of coagulation parameters was carried out on 100 Singaporean acceptors using Norplant for contraceptive purposes. At the end of 2 years of use, results from this ongoing study indicate that these acceptors continue to have an increased predisposition to thrombosis as evidenced by significant increases in platelet count and aggregability. The shortened but stable prothrombin time and activated partial thromboplastin time and increase in certain coagulation factors indicate that Norplant acceptors still have a possible potential for hypercoagulation at the end of two years of use.
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PMID:Two-year follow-up of changes in clinical chemistry in Singaporean Norplant acceptors: haemostatic changes. 249 88

The association between contraceptive agents and the risk of thromboembolism is known. Norplant is a relatively new subdermally implanted contraceptive delivery system, which releases a continuous low dose of the progestagen levonorgestrel over a period of 5 years or more. The present study examines 22 hemostatic parameters in 100 healthy, nonsmoking Singaporean women after 6 months and after 1 year of Norplant use. At the end of 1 year, there was a significant increase in platelet count and platelet aggregation, both of which indicate an increased risk of thrombosis. Prothrombin time and activated partial thromboplastin time were both significantly shortened, and Factor V and Factor X levels were elevated. These results indicate an increased potential for hypercoagulation. Mean values of hematocrit and hemoglobin were elevated. There was a decrease in the level of Factor VII and an increase in antithrombin III antigen level. It is intended that this longitudinal study be continued for the full 5 years, and it is suggested that similar studies be conducted in different populations.
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PMID:The effects of Norplant on clinical chemistry in Singaporean acceptors after 1 year of use: I. Haemostatic changes. 313 60

The effect of Norplant subdermal implants on 22 different hemostatic variables was determined in 100 women attending the Fertility Control Clinic of the Singapore National University Hospital before and after 6 and 12 months of use. The factors analyzed were: hematocrit, hemoglobin (Hb), prothrombin time (PT), activated partial thromboplastin time (APTT), platelet count, fibrinogen, coagulation factor II, Factor V,Factor VII, Factor VIII, Factor VIIIR:Ag, Factor X, plasminogen activator, FDP, plasminogen (imm), antithrombin III (functional), antithrombin (antigen), protein C, alpha2-antiplasmin, alpha2-macroglobulin, alpha2-antitrypsin, platelet count, platelet aggregation (ADP), and platelet aggregation (collagen). The factors that differed significantly after 12 months were: Hb,PT,APTT, Factors II,V,VII, and VIIIR:Ag, Plasminogen (imm), antithrombin III(antigen), alpha2-antiplasmin, platelet count, and platelet aggregation. Most of these differences, while significant, were still within the normal range, except for PT,APTT, and platelet count. The subjects were considered to be in an enhanced risk for hypercoagulation and thrombosis.
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PMID:The effects of Norplant-2 rods on clinical chemistry in Singaporean acceptors after 1 year of use: haemostatic changes. 314 69

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

Many reports have indicated that oral contraceptives can increase the incidence of thromboembolic disorders. Norplant, an implant contraceptive containing levonorgestrel, has been developed recently. The aim of this study is to observe the effect of Norplant on some hemostatic parameters. The subjects in this study were divided into 5 groups. Group 1 (control) consisted of 25 female blood donors. Group 2 (N = 25), group 3 (n = 25), group 4 (n = 17) and group 5 (N = 20) consisted of subjects who had been using Norplant for 2, 3, 4, and 5 years, respectively. Prothrombin time, activated partial thromboplastin time, fibrinogen level, assay of F VII and X, antithrombin III activity, plasminogen activity, alpha 2-plasmin inhibitor activity and platelet aggregation test were done in all subjects. Our results showed that there was a significant difference (p < 0.05) on platelet aggregation induced by 10 microM of ADP between the control group and Norplant users for more than 2 years, while the other parameters did not differ significantly. It is concluded that 5 years users of Norplant did not alter blood coagulability, but increased platelet response to 10 microM of ADP.
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PMID:The effect of Norplant on some hemostatic parameters in Indonesian women. 788 84

A total of 55 non-breastfeeding informed volunteers were recruited into a prospective longitudinal study from a family planning clinic between September and December 2002. Blood samples were collected at pre-treatment and at 3, 6 and 12 months follow-up, for packed cell volume, platelet count, prothrombin and activated partial thromboplastin time. Statistical analysis was with paired t-tests. The level of significance was set at 5%. Each subject received a menstrual calendar to chart all bleeding and spotting events. The mean age and weight of acceptors were 32.5 +/- 6.1 years and 63.6 +/- 9.6 kg, respectively. Mean packed cell volume (PCV) was 35.2 +/- 2.9% at pre-insertion. This rose to significant mean +/- SD values of 36.5 +/- 3.1%; p<0.05, 38.5 +/- 2.8%; p<0.0001 and 38.4 +/- 3.6%; p<0.0001 at 3, 6 and 12 months, respectively when compared with the pre-insertion mean value. The mean values of the platelet count showed no significant change at 3 months (238,448 +/- 68,618 mm(3); p>0.9), compared with pre-treatment value (240,545 +/- 96,769 mm(3)). There was a significant reduction in mean concentration at 6 months (p<0.009; 191,364 +/- 55,531 mm(3)) and at 12 months (p<0.003; 202,773 +/- 81,544 mm(3)) follow-up. The prothrombin and the partial thromboplastin time did not show significant change over their pre-insertion mean values of 12.0 +/- 1.1 s and 36.9 +/- 2.9 s, respectively. At 12 months, 79.5% (35) of the users reported an abnormal menstrual pattern, which included 54.5% (24) reduced bleeding pattern, 20.5% (9) increased bleeding and 4.5% (2) of combination of patterns. Only 20.5% (9) had a normal menstrual pattern. The continuation rate was 98%, as one user discontinued because of headaches. Norplant (the registered trademark of the Population Council for levonorgestrel subdermal implants) had an effect on the bleeding pattern - mainly reduced bleeding. The increase packed cell volume is beneficial in preventing anaemia. There was no detrimental effect as a result of the reduced but normal platelet count and users were not predisposed to clotting abnormalities.
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PMID:Evaluation of haemostatic function in Nigerian Norplant acceptors after 12 months of use. 1609 25

Separately, von Willebrand disease and menorrhagia are two relatively common conditions; in combination they occur at a prevalence of approximately 11-16%. Such patients exhibit a reduced quality of life and can incur a relatively high rate of gynecologic interventions; for example dilatation and curettage, endometrial ablation and hysterectomy. Initial evaluation involves a focused history for the following bleeding symptoms: menorrhagia since menarche, easy bruising of greater than 5 cm 1-2 times/month, frequent gum bleeding when flossing or brushing teeth or epistaxis 1-2 times/month. In addition, for those who have already undergone invasive interventions with the subsequent risk for hemorrhage, inquiry should be made regarding excessive bleeding with childbirth, dental tooth extraction and/or surgery. Step-wise testing includes a complete blood cell count and an assessment of the prothrombin time, activated partial thromboplastin time, iron profile, serum creatinine and thyroid-stimulating hormone level, followed by Factor VIII level, von Willebrand factor antigen and ristocetin cofactor, followed by consideration of platelet aggregation studies. Additional hemostatic studies may include obtaining a Factor XI level and euglobulin clot lysis time. Intuitively, failure to diagnose an underlying hemostatic disorder may lead to continued menorrhagia and diminished quality of life, as well as unnecessary surgical interventions that may in turn be fraught with an increased risk of bleeding. The management of von Willebrand disease-related menorrhagia involves consideration of the patient's age, childbearing status and preference. In the adolescent, surgical intervention is not an option, whereas an older patient beyond her childbearing years may choose a hysterectomy as a definitive treatment in lieu of continued medical therapy with intranasal/subcutaneous 1-deamino-8-D-arginine vasopressin (DDAVP), oral antifibrinolytic agents or oral contraceptive. The sexually active patient may initially choose a trial of oral contraceptive or the levonorgestrel intrauterine device, Mirena((R)). Pending ongoing comparative trials in von Willebrand disease-related menorrhagia of intranasal DDAVP, tranexamic acid and the levonorgestrel intrauterine device, specific recommendations cannot be made at present regarding the superiority of one intervention compared with another. It should also be noted that the dose and schedule of intranasal DDAVP, tranexamic acid and epsilon-amino caproic acid have not been well established and warrant further study in combination and at various doses and schedules.
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PMID:von Willebrand disease and other disorders of hemostasis in the patient with menorrhagia. 1980 40

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