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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Researchers compared data on women using the 2-rod Norplant implant system formulated with the Silastic elastomer 4092 (original system) with those using the 2-rod Norplant made with a different elastomer (Q74910) (reformulated system) to examine their hemostatic effects during 36 months of use. All 33 women lived in Singapore. Both systems released the same amount of levonorgestrel at the same rate. In most hemostatic parameters, prolonged use of both 2-rod Norplant implant systems effected similar changes: increased hemoglobin concentration and hematocrit values, increased fibrinogen levels, no increased platelet activation, no increased activation of coagulation or fibrinolysis/inhibitor, no significant changes in platelet numbers, no significant changes in tissue plasminogen activator, and decreased urokinase-like plasminogen activator. Factor VII was higher after 18 months than it was during the first 12 months in original Norplant users (p 0.001). The factor VII level at 36 months during reformulated Norplant use was significantly higher than it was during the first 24 months of use (p 0.001). None of the changes common to both systems suggested tissue breakdown. Plasminogen activator inhibitor antigen levels were significantly lower during 12-36 months than preinsertion levels in original Norplant users, while they fell insignificantly in reformulated Norplant users. The increased levels of fibrinogen and factor VII at 36 months are areas of concern since they are markers of hypercoagulation and are linked to increased arteriosclerotic and cardiovascular risks. Researchers of this on-going study will later publish the two systems' effects on hemostasis after 5 years of use.
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PMID:The effects of reformulated 2-rod Norplant implant on hemostasis after three years. 892 75

The effects of progestogens on hemostatic function seems to be minimal, however, in this longterm surveillance study of the effects of Norplant among 100 healthy, nonsmoking, nonalcohol drinking, and nonlactating Singaporean women indicates the possibility of an increased predisposition of thrombosis. Clinical assessment and blood sampling were taken prior to insertion and at 6, 12, 24, 36, and 48 months. Laboratory tests included prothrombin time (PT), activated partial thromboplastic time (APTT), hematocrit and platelet count as hemostatic measures. Also measured were fibrinogen, coagulation factor II, a 1-stage assay for factors V and VII, factor VII, factor X, antithrombin III, plasminogen activator activity on the fibrin plate and FDP, platelet aggregation, factor VIIIR. 20 normal controls not on any medication were used and international standards were applied in most cases. The coefficients of variation of the various tests with reference control plasma or sera are summarized. The paired t test was used to assess statistical differences. Skewed results were analyzed with the Wilcoxon signed rank test. % changes between pre- and postinsertion levels were also utilized. The results were that the hemoglobin concentration increased from 12.1 gm/dl to 13.4 gm/dl in the 1st year, and then decreased to preinsertion levels within 3 years, and increased to 13.3 gm/dl in the 4th year. The 4th year also reflected no menstrual disorder. PT and APTT appeared significantly shortened in year 1. PT continued to shorten in 3 more years, while APTT increased to the preinsertion mean. Vitamin K dependent factors II and VII decreased significantly in year 1, while factors V and X increased significantly. Factor II increased minimally within 2 more years, but decreased again in year 4. Factor VII continued to decrease over the 4 years. The concentration of factors II and VII were significantly lower after 4 years. Factor V increased 14.4% in year 1, but decreased below preinsertion levels in the next 3 years, and then decreased to preinsertion levels in year 4. No significant changes in fibrinolytic activity occurred in 4 years. Major changes occurred in mean platelet count, which rose significantly in year 1 and increased concentration in year 4. In 4 years, platelet aggregation using ADP or equine collagen rose significantly. Serious thought must be given to the risk of thrombosis and potential for hypercoagulation.
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PMID:Haemostatic function changes in Singapore women using Norplant implants: a four year review. 1228 17