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

The introduction of factor VIII and IX concentrates in the early 1960s brought a significant change in the hemophiliac's life. In consequence hemophilia treatment has been improving rapidly since, and today most life-threatening hemorrhages are controlled by replacement therapy. Hemophilic arthropathy through recurrent joint and muscle bleedings occurs later in life and is often limited to one joint only. Major surgery in hemophiliacs involves little more risk than in non-hemophilic patients, provided of course there is close teamwork between surgeon and hematologist. The most frequent causes of death are no longer hemorrhages but blood-product-associated AIDS and hepatic failure. Fortunately these side effects have been overcome by the use of virus-inactivated concentrates which in Switzerland have been generally administered since 1986. Factor VIII and IX concentrates must contain a precisely declared quantity of factor VIII and IX activity respectively, with a high specific activity. High-purity concentrates should be preferred because of the hazardous effect of foreign proteins administered intravenously in large quantities over a long period. Activation of fibrinolysis with consequent failure of hemostasis or even worsening of hemorrhage may be a clinically relevant side-effect of DDAVP therapy. When DDAVP is used for prophylactic treatment before surgery, an interval of one hour between the intravenous administration of DDAVP and surgery ensures the latter is performed at the time of highest factor VIII and von Willebrand factor level but with already decreased t-PA and fibrinolytic activity. If DDAVP is used in case of hemorrhage or postoperatively, however, the whole fibrinolytic potential must be taken into account. In these cases subcutaneous administration is advantageous due to more protracted t-PA release and the subsequent lower fibrinolytic activity, which can more easily be neutralized by tranexamic acid. To prevent hemophilic arthropathy, correct replacement therapy in hemarthroses is essential: it should be performed as early as possible, preferably in a home therapy program; adequate levels of factor VIII or IX should be achieved and maintained over a sufficient length of time. Hemophiliacs who did not receive replacement therapy during childhood often need major surgery because of severely destructed joints. Joint replacement by total knee and hip prostheses has proved very successful if certain special conditions are fulfilled. Surgical indications should, however, be carefully considered and the possibilities and limits of replacement therapy should be well known. Blood-product-associated hepatitis will be of prognostic relevance in many hemophiliacs treated formerly with non-virus-inactivated concentrates.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Current clinical aspects in hemophilia treatment]. 250 19

A new method for isolation and culture of endothelial cells from bovine coronary artery (BCoAEC) is presented. This method involves in situ perfusion and digestion of main coronary arteries with a collagenase solution. The isolated cells were cultured and maintained through many cell passages in Dulbecco's Modified Eagle's Medium supplemented with fetal bovine serum derived from either whole blood or plasma. Confirmation of these cells' endothelial origin was obtained by demonstration of typical morphologic and growth characteristics of endothelium, immunofluorescent staining with antibodies to von Willebrand factor (Factor VIII: vWF), and measurement of plasminogen activator (PA). In addition, production of PA was inhibited by enzymatically active thrombin as has been previously described with bovine aortic endothelial cells in culture.
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PMID:Bovine coronary artery endothelium: in vitro culture and production of plasminogen activator. 308 24

Factor VIII (FVIII) and plasminogen activator activity (PAA) rise during hypoglycaemia, and this might contribute to the vascular complications of diabetes. Similar changes in haemostasis accompany raised plasma levels of vasopressin (aVP) and adrenaline. To investigate the effects of these hormones on haemostasis during hypoglycaemia and the role of plasma insulin concentrations, eight insulin-dependent diabetic patients underwent controlled hypoglycaemia for 20 min and 13 diabetic patients were investigated during hyperinsulinaemia with blood glucose maintained at 8.0 mmol/l. During hypoglycaemia, insulin levels increased to median values of 114 mU/l, a VP rose from 0.5 to 4.4 (p less than 0.005) pg/ml and adrenaline from 0.4 to 4.4 nmol/l (p less than 0.005). FVIII coagulant activity (FVIII:C) rose from 0.75 to 1.09 IU/ml (p less than 0.01) and the ristocetin co-factor (FVIIIR:Co) and von Willebrand factor antigen (vWF:Ag) showed similar responses. PAA increased from 156 to 745 units (p less than 0.005). During hyperinsulinaemia, insulin rose following infusion from 24 to 52 and 118 mU/l, maintained for an hour at each level. Despite this, plasma aVP, FVIII:C, FVIIIR:Co, vWF:Ag and PAA remained unchanged. This study indicates that the marked changes in FVIII, vWF and PAA concentrations which accompany hypoglycaemia depend on low blood glucose and not raised plasma insulin. The response in probably mediated by increases in adrenaline and aVP, which are part of the physiological response to hypoglycaemia.
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PMID:Hormonal control of haemostasis during hypoglycaemia in diabetes mellitus. 311 5

Haemostatic variables were assessed in 43 patients, 28 insulin-dependent and 15 non insulin-dependent. Maximum aggregation by low concentrations of adenosine diphosphate (ADP) or arachidonic acid and elevated plasma concentrations of TxB2, Factor VIII, vWF:Ag, RCoF and fibronectin (Fnct) indicated a hypercoagulable state. The manifestation of vasculopathy was associated with elevated concentrations of RCoF, Fnct, Hbalc, cholesterol and triglycerides, while impaired fibrinolysis was demonstrated by decreased t-PA levels and the absence of crosslinked fibrin degradation products (XL-FDP).
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PMID:Diabetes mellitus as a hypercoagulable state: its relationship with fibrin fragments and vascular damage. 311 98

The fibrinolytic system comprises a proenzyme, plasminogen, which can be converted to the active enzyme plasmin, which will degrade fibrin. Plasminogen activation is mediated by plasminogen activators which are classified as either tissue-type plasminogen activator (t-PA) or urokinase-type plasminogen activator (u-PA). Inhibition of the fibrinolytic system may occur at the level of the activators or at the level of generated plasmin. Plasmin has a low substrate specificity and when circulating freely in the blood will degrade several proteins including fibrinogen, Factor V and Factor VIII. Plasma does, however, contain a fast-acting plasmin inhibitor, alpha 2-antiplasmin, which will inhibit free plasmin extremely rapidly (t1/2: 0.1 s) but which reacts much slower (10(3)-fold) with plasmin bound to fibrin. A "systemic fibrinolytic state" may, however, occur by extensive activation of plasminogen (conc. in plasma 2 microM) and depletion of alpha 2-antiplasmin (conc. in plasma 1 microM). Clot-specific thrombolysis therefore requires plasminogen activation restricted to the vicinity of the fibrin. Two physiological plasminogen activators, t-PA and single-chain u-PA (scu-PA) induce clot-specific thrombolysis, however via entirely different mechanisms. t-PA is relatively inactive in the absence of fibrin, but fibrin strikingly enhances the activation rate of plasminogen by t-PA. This is explained by an increased affinity of fibrin-bound t-PA for plasminogen and not by alteration of the catalytic rate constant of the enzyme. The high affinity of t-PA for plasminogen in the presence of fibrin thus allows efficient activation on the fibrin clot while no significant plasminogen activation by t-PA occurs in plasma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fibrin-specific thrombolytic agents. 312 44

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

Blood coagulation and fibrinolysis variables have been studied in the normal puerperium in order to facilitate the decision to discontinue thrombosis prophylaxis after delivery. 16 women were followed longitudinally from the 1st to the 6th week post partum. Factor VIII activity and related antigen, fibrinogen, fibrinopeptide A, antithrombin III, plasminogen, tissue plasminogen activator (t-PA), fast inhibitor of t-PA, alpha 2-antiplasmin, urokinase inhibitors, fragment B beta 15-42 and kallikrein inhibition were analyzed. Both blood coagulation and fibrinolysis were significantly increased during the first 2 weeks, although simultaneously increased inhibitor capacity of both systems was present. 3 weeks post partum, blood coagulation and fibrinolysis were generally normalized, although the inhibitors remained raised compared to nonpregnant controls throughout the observation period.
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PMID:Changes in blood coagulation and fibrinolysis in the normal puerperium. 393 Mar 49

In nine patients with non-malignant diseases undergoing major upper abdominal surgery, the mechanism of the postoperative fibrinolytic shut-down was investigated because of its potential significance for postoperative deep vein thrombosis by employing new and specific methods for assessing and stimulating the fibrinolytic system. The shut-down was found to result from an impairment of the balance between tissue-type plasminogen activator, t-PA, and its recently discovered fast-acting inhibitor. In this balance, the t-PA antigen concentrations both in resting conditions and after stimulation evoked by desamino-D-arginine vasopressin (DDAVP) were found to be unchanged by surgery. However, there was a significant postoperative increase in t-PA inhibitor levels. The release of t-PA under the stimulus of DDAVP infusion overcame the postoperative shut-down of t-PA activity. However, DDAVP infusion was associated with potentially unfavourable increases in the Factor VIII/von Willebrand factor complex. The discovery of increased t-PA inhibitor in the postoperative period opens new possibilities for a rational approach to reduce or abolish the postoperative fibrinolytic shut-down.
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PMID:Fibrinolytic shut-down after surgery: impairment of the balance between tissue-type plasminogen activator and its specific inhibitor. 393

Plasma coagulation factors were measured in twelve male insulin-dependent diabetics with no retinopathy, ten with background and ten with proliferative retinopathy and ten non-diabetics. Factor VIII pro-coagulant activities (VIII:C), ristocetin cofactor activities and factor VIII-related antigen concentrations (VIIIR:ag) were significantly related to the severity of diabetic retinopathy (P less than 0.025, trend test). The mean ratio of VIII:C/VIIIR:ag was lower in the diabetics with proliferative retinopathy than in the other groups of diabetics (P less than 0.05) or the controls (P less than 0.02). Concentrations of alpha 2 macroglobulin and alpha 1 antitrypsin were highest in diabetics with proliferative retinopathy (0.1 greater than P greater than 0.05, trend test) but mean prothrombin and activated partial thromboplastin times and mean concentrations of alpha 2 antiplasmin, plasminogen activator and antithrombin III were similar in all groups. Concentrations of the platelet-specific protein beta thromboglobulin, though higher in diabetics than controls (P less than 0.005), were not related to retinopathy. The plasma concentrations of coagulation factors did not correlate with creatinine clearance and there were no significant differences between groups in concentrations C-reactive protein; this suggests that the raised concentrations of coagulation factors in diabetics with retinopathy were not a result of associated nephropathy or an 'acute phase protein' response to diabetic tissue damage. Increased coagulation activity in diabetics may contribute to the development of retinopathy.
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PMID:Plasma haemostatic factors and diabetic retinopathy. 619 95

Vascular or tissue-type plasminogen activator (TPA) is a key enzyme in physiologic fibrinolysis. To study the role of prostaglandins in modulating the synthesis and release of TPA in vivo, we prospectively studied the effect of aspirin (650 mg/d X 2) on TPA activity in 13 human subjects before and after 10 min of forearm venous occlusion. TPA activity was quantified by a newly developed enzyme-linked immunosorbent assay that both measures and differentiates between TPA and urokinase (UK)-like plasminogen activator activity. This assay is based on the observation that the concentration of alpha 2-plasmin inhibitor-plasmin complexes in Reptilase-clotted plasma increases linearly in proportion to the amount of activator added. Resting TPA activity was higher in women than in men (0.56 +/- 0.59 vs. 0.15 +/- 0.11 U/ml, P = 0.049). Venous occlusion induced an eightfold rise in TPA activity in women (to 4.5 U/ml, P = 0.006) and a 15-fold rise in men (to 2.28 U/ml, P = 0.004), whereas UK activity was not detected. Aspirin inhibited the rise in TPA activity after venous occlusion by 69% in men (P = 0.004) and 70% in women (P = 0.014). In contrast, aspirin had no effect on pre- or post-occlusion hematocrits or Factor VIII-related antigen levels. There was no correlation between plasma salicylate level and percentage inhibition of TPA. Neither exogenous aspirin (0-1 microgram/ml) nor salicylate (0-70 micrograms/ml) inhibited the generation of alpha 2-plasmin inhibitor-plasmin complexes by exogenous TPA or interfered with the assay system. We conclude that aspirin may have an antifibrinolytic effect in man that has not been previously described.
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PMID:Aspirin inhibits vascular plasminogen activator activity in vivo. Studies utilizing a new assay to quantify plasminogen activator activity. 623 45


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