Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Homozygous protein C (PC) deficiency is a rare genetic defect that usually results in fatal thrombotic complications (purpura fulminans and DIC), but it can be successfully managed with oral anticoagulants or PC replacement. The successful use of PC replacement for two individuals is described. The activity and antigen levels of PC in fresh frozen plasma (FFP) and prothrombin complex concentrate (PCC) are also reported. The concentration of PC in FFP is 87 +/- 15 units/dl. PC is present in all PCC analyzed; however, a ten-fold difference between the various brands and/or lots is noted. The PC activity and antigen correlates well with no significant levels of APC. Upon infusion of FFP into two homozygous PC-deficient children, the PC levels obtained were less than or equal to 30 units/dl post-infusion and undetectable after 12-18 hr. With infusions of PCC, plasma levels of PC obtained were 100-145 units/dl and less than 10 units/dl after 48 hr. The percent recovery and half-lives of PC from FFP and PCC were 49.8% and 7.8 hr, and 84% and 7.4 hr, respectively. One infant was treated every 48 hr for 2 years without significant purpura fulminans or DIC complications. The levels of the other PC system components did not change during the infusion of the PC-rich material. Based on this information, a specific replacement protocol has been developed using a PC-rich concentrate. However, several problems may arise with the "less pure" PC-rich concentrates: catheter-tip thrombosis, related large vessel thrombosis and blood-transmitted diseases. With a specific PC concentrate, replacement therapy is a viable alternative for the long-term management/treatment of homozygous PC deficiency.
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PMID:Protein C survival during replacement therapy in homozygous protein C deficiency. 150 96

We measured concentrations of the natural anticoagulant protein C; its cofactor, protein S; and the carrier protein C4b-binding protein (C4BP), in 24 patients with severe infection and 13 with septic shock. Decreased antithrombin III levels were found in 16 of 24 infection patients and all shock patients; high thrombin-antithrombin (TAT) complexes were present in 16 of 24 infection and 12 of 13 shock patients. Protein C concentrations were significantly reduced compared to healthy blood donors, to 60 +/- 14% (infection) and 47 +/- 20% (septic shock) (mean +/- 1 SD). Total protein S levels were not reduced (119 +/- 36.7 and 88 +/- 20.0%, normal value 96 +/- 15%). Free protein S was also normal (27 +/- 9.4 and 30 +/- 8.7%, normal value 29 +/- 9%). The percentage free of total protein S was normal in shock patients (35 +/- 8.5%), but significantly reduced in patients without shock (23 +/- 5.3%). C4BP was significantly higher than normal in the latter group (135 +/- 43%), but not in the shock group (118 +/- 40%), possibly due to increased consumption. Thus, no deficiency of total or free protein S was found in these patients, who had evidence of activated coagulation but no clinical DIC.
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PMID:Protein C, protein S and C4b-binding protein in severe infection and septic shock. 182 15

Protein C (PC) is the central component of a major antithrombotic regulatory system with both anticoagulant and profibrinolytic properties. A deficiency of PC is one of several hereditary abnormalities of haemostatic proteins that have been described in patients with a propensity for thromboembolic complications. Major morbidity is often seen in these patients. The various aspects of hereditary PC deficiency in terms of clinical presentation, genetics, diagnosis and treatment of both homozygous and heterozygous states will be presented. In heterozygous deficiency, the levels of plasma PC are usually between 35% and 65% of normal, whereas the majority of normal individuals have levels between 70% and 130%. PC-deficient patients usually develop venous thrombotic complications between the ages of 15 and 40 years with a high incidence of DVT and pulmonary embolism. The majority of thrombotic lesions appear to develop spontaneously; others are associated with trauma, surgery or pregnancy. Treatment of symptomatic patients is initial heparin therapy followed by coumadin. After multiple thrombotic events, lifelong oral anticoagulant therapy is necessary. The potential complications of treatment are coumadin-induced skin necrosis, heparin-induced thrombocytopenia and bleeding. Homozygous PC deficiency, a rare but fatal hereditary condition, manifests itself with massive DIC and purpura fulminans in the newborn period. Effective treatment for these infants can be instituted with either oral anticoagulant therapy or PC replacement. The heterozygous deficiency of PC is similar to that found in other inherited disorders in that several genetic mechanisms are responsible for the expression of the disease. Both quantitative and qualitative decreases in PC exist, the former being type I deficiency and the latter, type II. The best initial diagnosis of either form involves a clotting (functional) assay while differentiation between the two also requires an antigenic (immunological) assay. Autosomal inheritance with significant variable penetrance is found with profound clinical implications. In summary, PC deficiency is one of a group of inherited disorders termed hereditary thrombotic disease, which may have serious implications for patient morbidity and mortality.
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PMID:Hereditary protein C deficiency: a review of the genetics, clinical presentation, diagnosis and treatment. 210 16

Homozygous protein C deficiency or homozygous protein S deficiency are rare genetic diseases with catastrophic and fatal purpura fulminans-like or thrombotic complications occurring during the neonatal period. These diseases can now be successfully treated. Purpura fulminans is at least in part a cutaneous manifestation of the syndrome of systemic DIC. It is characterized by microvascular thrombosis in the dermis followed by perivascular hemorrhage, necrosis, and minimal inflammation. Laboratory findings are consistent with DIC. Although the pathogenesis is not fully understood, the DIC in purpura fulminans appears to involve the skin selectively. The development of purpura fulminans from homozygous protein C or protein S deficiencies can be separated into the two distinct phases. The first phase is the time period when the initial reversible lesions develop and grow. This reversible progression can be halted and reversed with the administration of protein C or protein S. The second phase is the irreversible stage in which the lesion continues to develop into a necrotic lesion, whether or not treated with protein C. This irreversible lesion will ultimately develop into a large full-thickness necrotic injury of the skin. It is very similar to the lesions seen in idiopathic purpura fulminans, warfarin-induced skin necrosis, and acute infectious purpura fulminans. Unfortunately, our current understanding of the mechanism or mechanisms of the induction and propagation of the purpura fulminans-like lesions in homozygous protein C or protein S deficiencies is minimal, since it has never been studied. We can only speculate on the mechanism based on laboratory data and comparison with the little that is known about the other similar types of lesions.
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PMID:Neonatal purpura fulminans due to homozygous protein C or protein S deficiencies. 214 4

Anticoagulant as well as anti-platelet drugs are important medicines for the prophylaxis in various kinds of thrombotic diseases. However, the conventional anticoagulant drugs, heparin and coumarin congeners, have some disadvantages and limitations in clinical usage. Recently newly anticoagulants, both synthetic and recombinant, have been developing. They include synthetic thrombin inhibitor, recombinant hirudin, protein C and thrombomodulin. Here we reviewed synthetic thrombin inhibitor, Argipidine (MD805) in clinical trial and investigated its effect on thrombin catalyzed protein C activation on endothelial cells. Argipidine inhibited the protein C activating activity of thrombin on endothelium in a dose response manner. Next we examined the effect of Argipidine on thrombin-induced endothelin release from cultured endothelial cells. The augmentation of endothelin release from endothelial cells by thrombin was also inhibited by Argipidin. The effect was considered one of the advantage of this drug in the treatment of thrombosis. Recombinant thrombomodulin had potent antithrombotic effect on thrombin-induced acute thromboembolism in mice, suggesting that this may be expectant anticoagulant for DIC or thromboses in human.
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PMID:[Synthetic anticoagulant]. 217 Jul 4

Hemostatic abnormalities are present in a majority of patients with metastatic cancer. These abnormalities can be categorized as 1) increased platelet aggregation and activation, 2) abnormal activation of coagulation cascade, 3) release of plasminogen activator, and 4) decreased hepatic synthesis of anticoagulant proteins like Protein C and antithrombin III. The abnormal activation of coagulation cascade is mediated through release of Tissue Factor, Factor X activators, and other miscellaneous procoagulants from the plasma membrane vesicles of tumor cells. Macrophages of a tumor-bearing host also produce increased amounts of Tissue Factor. Production of Factor X activators and macrophage Tissue Factor is decreased by warfarin. The ability of the tumor cells to produce platelet-aggregating activity and plasminogen activator parallels their metastatic potential in animal and experimental systems. These studies also show that antiplatelet agents and antibodies against plasminogen activator can suppress the metastatic process. One or more laboratory abnormalities of hemostasis can be shown in up to 95% of patients with metastatic cancer. These abnormalities, however, are unable to predict subsequent development of thromboembolic or hemorrhagic complications. Clinical complications occur in 9-15% of the patients in the form of thrombotic or hemorrhagic disorders. The therapy of tumor-related coagulopathy should be guided by its clinical expression. Subclinical DIC should not be treated. Coumadin is generally ineffective for therapy of thrombosis in cancer patients. There is no consensus regarding the use of heparin in acute promyelocytic leukemia (APL). The defibrination in APL may be from disseminated intravascular coagulation as well as systemic fibrinolysis, as shown by decreased alpha 2 antiplasmin levels. In such cases, epsilon aminocaproic acid plus heparin therapy may be of benefit.
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PMID:Hemostasis in malignancy. 174 46

Early diagnosis and immediate treatment of the disease responsible for DIC are most important for successful therapy of DIC. Furthermore, it is also necessary to use anticoagulant agents in most cases of DIC. The agents may be classified on the basis of their mode of anticoagulant action into three groups: ones with antithrombin effect, ones with anti-Xa effect or ones with both effect, and each agent is hoped to be chosen appropriately for development of DIC in near future. At present, such anticoagulant agents as standard heparin, antithrombin-III concentrate, gabexate mesilate, nafamostat mesilate, MD-805, low molecular weight heparin, heparan sulfate, activated protein C, are known as drugs for DIC, and each of them was effective for improvement from DIC in our experience. Antifibrinolytic agents, which have been considered to be contraindicated for therapy of DIC, may be good indication for selected cases of DIC with enhanced fibrinolysis such cases as acute promyelocytic leukemia. Antiplatelet agents may be available for some cases of chronic DIC.
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PMID:[Treatment of disseminated intravascular coagulation]. 221 66

Plasma fibronectin was measured with Laurell's immunoelectroassay in 44 patients with meningococcal sepsis. The average value (15.0 +/- 7.9 mg/dl) was lower than that in normal children (27.4 +/- 8.7 mg/dl) (p less than 0.001). Fibronectin in patients correlated positively with antithrombin III (AT-III) values (p less than 0.02), but not with protein C (0.05 less than p less than 0.1). The decrease of fibronectin had no prognostic value. The fibronectin levels were lower in patients with disseminated intravascular coagulation (DIC+), than in those without DIC (DIC-) (p less than 0.02), but were lower in both groups than in a normal control group. A negative correlation between fibronectin and protein C was only present in DIC- patients (r: -0.773 = p less than 0.01). Fibronectin varied independent of AT-III and protein C in DIC+ patients. The study was repeated in 11 patients 24 hours after admission when fibronectin had decreased in 7/11 cases (mean decrease: -2.7 +/- 8.7 mg/dl). This variation correlated in a negative way with AT-III (r: -0.659 = p less than 0.05). In meningococcal sepsis fibronectin decreases very early, even in DIC- patients and its relationship to AT-III and protein C is different, depending on the presence of DIC and on the stage of evolution of the disease.
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PMID:Fibronectin in meningococcal sepsis. Correlation with antithrombin III and protein C. 231 65

The coagulation inhibitors are important components of control mechanisms which ensure the haemocoagulation equilibrium. One of them is protein C, whose level was followed in patients with DIC. and IM. In DIC. cases a significant decrease was noted with regard to the MI groups and healthy donors. EID and ELISA methods were used for testing. The patients exhibiting the protein C defect require a corresponding treatment which should suppress the thromboembolic complications.
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PMID:Clinical significance of protein C. 246 13

Protein C (PC) is a vitamin K-dependent serine protease which functions as the central regulatory protein with both anticoagulant and profibrinolytic properties. The PC levels in healthy term newborns are approximately one third of adult levels. Severely decreased levels of PC are seen in sick term and preterm infants. These neonates appear to have an increased incidence of thrombosis. Undetectable levels of PC are found in homozygous PC deficient infants with DIC and purpura fulminans symptoms. In this present study we report the composition and distribution of PC in term newborn and compare the results with adult values. Plasma was obtained from placental cord blood of 20 healthy term (38-42 weeks gestation) infants. PC was immunopurified, run on SDS-PAGE, and immuno-blotted. The composition of the PC molecule in neonatal plasma is identical to that seen in adults. Using densitometry to determine the distribution of the PC components, we observed a 2-fold increase in single chain PC in the neonate as compared to the adult. In the neonate, there was an inverse correlation between the level of total PC antigen and the amount of single chain. These findings suggest the possibility that the processing of PC may be developmentally influenced.
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PMID:Neonatal protein C: molecular composition and distribution in normal term infants. 259 75


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