Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein C (PC) is the zymogen of an anticoagulant serine protease and is converted to its active form (activated protein C: APC) by thrombin in the presence of thrombomodulin. APC plays an important role in regulating thrombosis and fibrinolysis by inhibiting not only blood coagulation factors Va and VIIIa but also type-1 plasminogen activator inhibitor (PAI-1). In the present study we examined the effects of human APC on tissue thromboplastin-induced disseminated intravascular coagulation (DIC) in rabbits and compared them with those of heparin. Both APC (300-3000 U/kg) and heparin (100-300 IU/kg) inhibited the decreases in platelet count and fibrinogen level equally. APC improved the prolonged bleeding time, but heparin aggravated bleeding with potent prolongation of activated partial thromboplastin time (APTT). Furthermore, in APC-treated animals, fibrin deposition in glomeruli was less than in heparin-treated animals. This result that APC accelerated local fibrinolysis by neutralizing PAI-1. From our findings, we concluded that APC can improve both coagulation and fibrinolysis in a DIC model and should be useful for the clinical remedy of DIC without having an adverse side effect like a bleeding tendency.
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PMID:Characteristic effects of activated human protein C on tissue thromboplastin-induced disseminated intravascular coagulation in rabbits. 787 94

Several parameters of fibrinolytic and protein C pathways were evaluated in three groups of patients with high (HR), moderate (MR) and low (LR) postoperative thrombotic risk undergoing major gynaecological surgery. The HR and MR groups were subjected to low molecular weight heparin (LMW) prophylaxis. A significant increase in plasminogen activator inhibitor type 1 (PAI-1) antigen and activity levels was observed in the HR patient group in comparison with the MR and LR groups in the preoperative and early postoperative period. In all the groups studied, the maximum increase in the levels of PAI-1 was seen on day 1 after surgery. However, the D-dimeric levels reached the highest level on day 7. A significant increase in activated protein C:alpha 1 antitrypsin (APC:alpha 1AT) complex levels was observed in the HR group in comparison with the LR group, and a strong decrease in protein C inhibitor in the early postoperative period was detected in all the groups. In spite of heparin prophylaxis, 2 HR patients were diagnosed as deep vein thrombosis (DVT) during the postoperative period. Both patients showed pre-operative levels of PAI-1 antigen or activity and APC:alpha 1AT complexes above the mean + 1 SD of the pre-operative levels in the HR group. In conclusion, in HR patients a hypofibrinolytic and hypercoagulable state was detected in the pre-operative and early postoperative periods. The prophylactic LMW heparin dose used in the present report (20 mg/day x 7) was insufficient to prevent DVT in the HR group. At present our HR patients are given higher doses of LMW heparin (40 mg/day x 7).
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PMID:Alterations in fibrinolytic and protein C pathways in gynaecological surgery: low molecular weight heparin prophylaxis. 798 53

Fish oils rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been demonstrated to alter coagulation and fibrinolysis variables. This study compared the effects of a traditional cholesterol-lowering diet and a similar diet, which had 50% of the linoleic acid (LA) replaced with the 18 carbon n-3 fatty acid, alpha-linolenic acid (ALA), on selected hemostatic variables. After a 2-week run-in diet with 39.5% total energy (en) from fat, 29 healthy male subjects consumed a 31.5% en fat diet with approximately 7% en from polyunsaturated fat and an ALA:LA ratio of either 1:1.2 (ALA-rich, n=15) or 1:21 (LA-rich, n=14) for 6 weeks. Blood was collected at the beginning, middle and end of test diets for analysis of Factor VIIc and VIIIc, fibrinogen, von Willebrand factor, activated protein C resistance (APC resistance), tissue plasminogen activator and plasminogen activator inhibitor type-1 activities and/or protein concentrations and platelet fatty acids. The ALA-rich diet tripled the percentage of platelet EPA, (P < 0.0005) but had little effect on coagulation and fibrinolysis. The APC ratio demonstrated increased anticoagulant activity on the ALA-rich diet (P < 0.001) only. Studies in patients with vascular pathologies are indicated to corroborate the current findings. Greater ratios of ALA:LA, achievable only with greater amounts of polyunsaturated fat, may be necessary to produce the effects demonstrated after feeding fish oils.
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PMID:Comparison of the effects of two low fat diets with different alpha-linolenic:linoleic acid ratios on coagulation and fibrinolysis. 992 May 17

Forty-eight healthy pregnant women were studied prospectively and longitudinally. Blood sampling was performed at 10-15, 23-25, 32-34 and 38-40 weeks of gestation, within one week and at eight weeks postpartum. Classic and modified activated protein C ratio decreased as pregnancy progressed. In the third trimester 92% of the ratios measured with the classic test were above the lower reference level whereas all modified test ratios were normal. Slight activation of blood coagulation was shown with increased levels of prothrombin fragment 1+2, soluble fibrin and D-dimer. Fibrinogen, factor VIII and plasminogen activator inhibitor type I and type 2 increased. Protein S and tissue plasminogen activator activity decreased. Protein C remained unchanged. No correlation was found between the decrease in classic APC ratio and changes in factor VIII, fibrinogen, protein S, prothrombin fragment 1+2 or soluble fibrin, nor between the increase in soluble fibrin and changes in prothrombin fragment 1+2, fibrinogen and D-dimer.
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PMID:APC resistance and other haemostatic variables during pregnancy and puerperium. 1023 33

Antiphospholipid antibodies are well recognized as associated with serious clinical complications such as arterial and venous thrombosis and recurrent spontaneous abortion. These complications are collectively called antiphospholipid syndrome(APS). The mechanisms responsible for the thrombosis are unclear. We reported three mechanisms. beta 2-glycoprotein I(beta 2GPI) inhibited activated protein C(APC) activity and, furthermore, APC activity decreased by the addition of monoclonal aCL and beta 2GPI. Monoclonal anticardiolipin antibodies(aCL) seemed to enhance the inhibition of APC procoagulant activity caused by beta 2GPI. Monoclonal aCL in the presence of beta 2GPI also increased the activity of plasminogen activator inhibitor(PAI)-1 in the mixture of tissue-plasminogen activator(t-PA) and PAI-1 by inhibiting the function of beta 2GPI, which increased the remaining t-PA activity in the mixture. The formation of thrombin-antithrombin complexes(TAT) in APS was impaired. The level of TAT in APS did not increase, however the level of prothrombin fragment 1 + 2 (F1 + 2) increased. Therefore, free thrombin present in patients' blood may contribute to thrombosis in APS. These reports indicate that thrombosis in APS may be caused by several thrombogenic factors that stimulate aCL.
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PMID:[Antiphospholipid antibodies and thrombosis: the putative mechanisms of hypercoagulable state in patients with anticardiolipin antibody]. 1081 Aug 73

Protein C (PC) is the zymogen of an anticoagulant serine protease and is converted to its active form (activated protein C: APC) by thrombin in the presence of thrombomodulin. APC plays an important role in regulating blood coagulation and fibrinolysis by inhibiting not only blood coagulation factors Va and VIIIa but also type-1 plasminogen activator inhibitor (PAI-1). In this study, it was reported that the antithrombotic effect of a human APC product (designated as CTC-111) compared with that of heparin and human PC on the deep venous thrombosis (DVT) model induced in mice by stasis caused by inferior vena cava ligation and operative invasion. Drugs were injected into a tail vein at -2, 30, 60, and 120 min after the inferior vena cava ligation. One-fifth amount of the total dosage of a given drug was injected at each time point. The wet weight of thrombus formed was reduced by APC or heparin administration, however, PC, which was equal to APC in protein amount, did not show any antithrombotic effect. To confirm whether human PC could be activated by mouse thrombin, PC was treated with mouse or human thrombin to measure the amount of APC formed. Mouse thrombin could activate human PC at a similar activation rate as human thrombin. These results suggest that externally administrated PC cannot exhibit antithrombotic effect in this DVT model due to slow activation rate to APC and that APC is a better antithrombic agent than PC for treating thrombotic diseases.
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PMID:Effect of activated human protein C on experimental venous thrombosis induced by stasis with operative invasion in mice. 1099 52

Protein C is the zymogen of an anticoagulant serine protease and is converted to its active form (activated protein C: APC) by thrombin in the presence of thrombomodulin. APC plays an important role in regulating coagulation and fibrinolysis by inactivating not only blood coagulation factors Va and VIIIa but also type-1 plasminogen activator inhibitor (PAI-1). The aim of the present study was to examine the effect of a human APC product (designated as CTC-111), compared with that of heparin, on the disseminated intravascular coagulation (DIC) induced by lipopolysaccharide (LPS) in rats. LPS (1 mg/kg/h) infusion was performed through a femoral vein for 4 h. One-fifth amount of the total dosage of CTC-111 or heparin was injected into the other femoral vein, followed by a 4-h infusion of the remainder. Both CTC-111 (10,000-100,000 U/kg) and heparin (400-800 IU/kg) inhibited the decrease in platelet count and fibrinogen level equally. The prolonged activated partial thromboplastin time and prothrombin time observed in DIC rats were further elongated in both CTC-111- and heparin-treated rats. But, this prolongation was less in CTC-111-treated rats than in the heparin-treated ones. Heparin inhibited the increase in fibrin and fibrinogen degradation products more prominently than CTC-111. On the other hand, CTC-111 strongly inhibited the increase in PAI-1 activity but heparin did not. These results suggest that CTC-111 may enhance fibrinolysis through its direct inhibitory effect on PAI-1. The parameters for liver or renal damage, i.e., plasma glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), creatinine (Cre) and blood urea nitrogen (BUN), were significantly increased by LPS infusion. Both CTC-111 (100,000 U/kg) and heparin (800 IU/kg) decreased the increase in GOT and GPT levels significantly, whereas neither affected the increase in Cre or BUN. From these results, the activation of the blood coagulation system might partially contribute to the progression of liver damage caused by LPS, and might be less involved in the progression of renal damage in this model. In conclusion, CTC-111 showed both anticoagulant and profibrinolytic activity in the LPS-induced DIC model without excessive prolongation of coagulation time. From these results, CTC-111 is expected to be a useful remedy for DIC without the risk of bleeding.
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PMID:Effect of activated human protein C on disseminated intravascular coagulation induced by lipopolysaccharide in rats. 1105 Jun 97

Acute myocardial infarction is a very rare event during pregnancy and bears the problem of misdiagnosis. However, about 150 cases have been published worldwide with a preponderance of anterior wall infarcts. With more women delaying childbearing until an older age and increasing prevalence of smoking in young women, it can be expected that all forms of coronary artery disease--including acute myocardial infarction--will be seen more often in the future. Among the causes of coronary artery occlusion in pregnancy are (1) rupture of very small coronary artery plaques triggered by different events, e.g., hypertension; (2) plain coronary artery disease; (3) dissection of coronary arteries; (4) coronary artery spasms with/without arterial thrombosis. Prompt diagnosis and immediate therapy are necessary to lower the high mortality of mother and fetus. The gold standard in the therapy of acute myocardial infarction during pregnancy is immediate coronary angiography and percutaneous transluminal coronary angioplasty (PTCA) with or without stent implantation. Application of thrombolytics (recombinant tissue plasminogen activator [rt-PA], r-PA, streptokinase [SK], urokinase [UK]) has been reported in single patients but should be limited to cases where acute PTCA is not available and where the infarct occurs before the 14th week of pregnancy because of possible embryopathy. If the patient is in the last 10 weeks of pregnancy, anticipation of delivery should be part of the medical planning. Consultation with an obstetrician must be obtained as soon as the patient enters the hospital. Besides bleeding complications, venous thrombosis with pulmonary embolism is among the most common causes of death during pregnancy. Pregnancy-related changes in physiology - increase in the resistance to flow from the lower extremities to the heart - and congenital coagulation abnormalities are most important to be recognized. This leads to the fact that superficial and deep venous thromboses occur more often in pregnancy than in the nonpregnant state. Among the coagulation abnormalities found in pregnancy are hypercoagulability (increased levels of fibrinogen, factor VII, factor VIII, factor X), decreased fibrinolytic activity due to an increased level of plasminogen activator inhibitor, increased adhesion and aggregation of platelets, decreased level of protein C and of the APC (activated protein C) ratio. Individual risks factors justifying diagnostic screening include contraception, smoking, immobilization, infection, adiposity, placental insufficiency, and a family history of thrombosis. It is even more important to establish/rule out the diagnosis of thrombosis in pregnancy than in the nonpregnant state, because the use of anticoagulants carries certain risks during pregnancy. Doppler vein studies should be used for diagnosis. If necessary, venography may be used with shielding of the maternal abdomen. Therapy consists of subcutaneous application of heparin, compression, and early mobilization. Alternatively, especially for long-term management, treatment with low molecular weight heparins is feasible. Thrombolytic treatment is contraindicated in most cases due to the high risk of bleeding complications. However, the application of thrombolytics can be contemplated in single cases after careful consideration of the pros and cons. Most cases of pulmonary embolism should also be handled conservatively with heparin. Only in massive pulmonary embolism with severe hemodynamic compromise, thrombolytic treatment is indicated. To guide future therapy in the patients, it is necessary to establish the lifetime risk of recurrent events by determining: APC resistance, prothrombin mutation 20210 A, homocysteine, AT III, protein C and S, antiphospholipid antibodies, and anticardiolipin antibodies.
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PMID:[Myocardial infarction and thromboembolism during pregnancy]. 1275 75

The purpose of this study was to detect changes in coagulation and fibrinolysis of post-severe acute respiratory syndrome (SARS) Chinese patients with osteonecrosis, investigate the aetiology of post-SARS osteonecrosis (ON), and select the sensitive molecular markers for identifying the susceptible population. For this study, blood samples were collected from 88 patients with post-SARS ON and 52 healthy people. Activated partial thromboplastin time (APTT), protein C (PC), antithrombin III (AT-III), plasminogen activator inhibitor (PAI), activated protein C resistance (APC-R), plasminogen (PLG), von Willebrand's factor(vWF), D-dimer (D-D), fibrinogen (Fib), and homocysteine (HCY) were examined by enzyme-linked immunosorbent assay (ELISA). We noted that blood agents of patients with ON changed obviously. APTT, PC, AT-III, PAI, APC-R, and PLG were significantly different between the two groups. Hypercoagulation and hypofibrinolysis were found in patients with post-SARS ON. Therefore, these examinations can be used to screen a population susceptible to ON. Measurements of APTT, PC, AT-III, PAI, APC-R, and PLG are sensitive blood tests for screening purposes.
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PMID:Changes in coagulation and fibrinolysis of post-SARS osteonecrosis in a Chinese population. 1654 17

Plasminogen activator inhibitor 1 is known to be elevated in patients with hepatic VOD after intensive chemotherapy. To re-establish endogenous fibrinolysis and to inhibit thrombin formation, we used non-APC (zymogen) to normalize PAI-1 levels. As a consequence of thrombin formation inhibition and the consecutive inhibition of the coagulation cascade, this treatment is expected to reduce the elevated D-dimer level. Six pediatric stem cell recipients with moderate or severe VOD after busulfan or total body irradiation conditioning regimen are reported here who were therapy-refractory to defibrotide or rt-PA therapy. All patients had low levels of PC activity (16-39%). The administration of PC (60-240 IU/kg) led to a rapid and sustained rise in PC activity (target level >80%) with near normalization of prothrombin and partial thromboplastin time in all patients. Elevated PAI-1 levels declined. Five of the six patients showed a good clinical response with prompt resolution of clinical, sonographic, and laboratory signs of hepatic blood flow obstruction, while one patient with severe VOD, as well as concomitant liver GVHD and CMV disease, had a slow but detectable response to PC therapy. All patients survived.
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PMID:Favorable response of pediatric stem cell recipients to human protein C concentrate substitution for veno-occlusive disease. 1723 23


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