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

The congenital combined deficiency of Factor V and Factor VIII, a rare bleeding disorder, was identified in a 25-year-old woman. She was admitted to our hospital with a complaint of genital bleeding. Her prothrombin time and activated partial thromboplastin time were prolonged. She had low levels of Factor V coagulant activity (F. V:C) 14%, and Factor VIII coagulant activity (F. VIII:C), 12%, and normal levels of von Willebrand factor antigen (vWF:Ag), ristocetin cofactor (Rcof) and Protein C antigen. Her Protein C inhibitor level was slightly low. Her Rcof, vWF:Ag and F. VIII:C were elevated following administration of 1-deamino-8-D-arginine-vasopressin (DDAVP), but her F. V:C remained unchanged. Four years later, her F. VIII:C rose to 70% during the course of her pregnancy, but her F. V:C value remained low. It was expected that the vaginal delivery would be possible at the termination of pregnancy. Premature rupture of the membranes and an anomaly of rotation appeared in the course of delivery, however, and cesarean section was accomplished without excess bleeding under replacement therapy with Factor VIII concentrates. These findings suggested that DDAVP and Factor VIII concentrates were useful for management of her delivery. However the mechanisms of the rise of plasma F. VIII:C during pregnancy in a case with congenital combined deficiency of Factor V and Factor VIII are unclear.
 ...
PMID:[Management of cesarean section under replacement therapy with factor VIII concentrates in a pregnant case with congenital combined deficiency of factor V and factor VIII]. 194 44

Protein C content and plasminogen activity were measured in plasma from 100 horses with signs of colic. Data were analyzed by grouping horses 4 ways. Each horse was allotted to 1 of 2 outcome groups (survivors and nonsurvivors), 1 of 3 broad-category diagnosis groups (inflammatory disorders, strangulating obstructions, and all other gastrointestinal disorders), and 1 of 2 clinical management groups (medical and surgical). In a fourth grouping, all horses (although numbers of horses included in each subgroup were small) were assigned either to specific diagnostic groups that had high expectation for activated hemostasis (intestinal ischemia, endotoxemia, jugular thrombosis, peritoneal adhesions, and laminitis) or to a control group, in which active hemostasis was unlikely. Within 2 to 24 hours after admission, nonsurvivors developed lower protein C content than did survivors. Protein C content and plasminogen activity became low during hospitalization in horses with strangulating obstructions and in horses having surgery. The results from the grouping by specific diagnosis must be considered pilot data because the numbers of horses in each subgroup were small. Although not statistically significant, trends were noticed in protein C and plasminogen: (1) horses with intestinal ischemia and endotoxemia developed low protein C content and plasminogen activity, (2) protein C content became low in horses that developed peritoneal adhesions or laminitis, and (3) plasminogen activity became low in horses that developed jugular thrombosis. Low protein C content or low plasminogen activity, or both, may be useful as predictors for outcome and for these specific complications of equine colic.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Use of newly developed assays for protein C and plasminogen in horses with signs of colic. 201 48

Protein C is a vitamin K-dependent zymogen of the serine protease, activated protein C (APC), an important regulatory enzyme in hemostasis. In view of the potential of human APC as an anticoagulant and profibrinolytic agent, the pharmacokinetics and tissue distribution of APC were studied in guinea pigs. The plasma elimination of a trace dose of 125I-APC was biphasic following an initial rapid elimination of approximately 15% of the injected dose within 1 to 2 minutes. This rapid removal of 125I-APC from the circulation was found to be a result of an association with the liver regardless of the route of injection. Essentially identical results were obtained with active site-blocked forms of APC generated with either diisopropylfluorophosphate or D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone, which indicates that the active site was not essential for the liver association. Accumulation of all three forms of APC in the liver peaked at 30 minutes and then declined as increasing amounts of degraded radiolabeled material appeared in the gastrointestinal tract and urine. Removal of the gamma-carboxyglutamic acid (gla) domain of diisopropylphosphoryl-APC resulted in a 50% reduction in the association with liver and an accumulation in the kidneys. Protein C and protein S were cleared from the circulation at rates approximately one-half and one-fourth, respectively, that of APC. Both in vitro and in vivo, APC was found to form complexes with protease inhibitors present in guinea pig plasma. Complex formation resulted in a more rapid disappearance of the enzymatic activity of APC than elimination of the protein moiety. These findings indicate two distinct mechanisms for the elimination of APC. One mechanism involves reaction with plasma protease inhibitors and subsequent elimination by specific hepatic receptors. The other mechanism involves the direct catabolism of APC by the liver via a pathway that is nonsaturable over a substantial dose range and independent of the active site. This pattern of elimination is distinctly different from that observed with the homologous coagulation enzymes thrombin, factor IXa, and factor Xa.
 ...
PMID:Pharmacokinetics of activated protein C in guinea pigs. 202 78

Protein Z is a vitamin K-dependent protein of unknown function present in normal bovine plasma at a concentration of approximately 0.1 microM. Quantitative affinity chromatographic studies using diisopropylphosphoryl (DIP)-thrombin-Affi-Gel 10 as the affinity matrix and free DIP-thrombin as the competitor demonstrated that protein Z interacts with DIP-thrombin with a dissociation constant of 0.15 +/- 0.05 microM. Binding was independent of Ca2+. Protein C and factor IX, other vitamin K-dependent clotting proteins with the same domain structure as that of protein Z, did not interact with immobilized DIP-thrombin under these conditions; and factor X interacted with an affinity 20-fold lower than that for protein Z. The Michaelis constant, Km, for hydrolysis of pyro-Glu-Pro-Arg-p-nitroanilide by thrombin was increased 1.8-fold, from 130 to 230 microM, as a result of the binding of protein Z and the Km for H-Val-Leu-Arg-p-nitroanilide 1.4-fold, from 390 to 560 microM. From these kinetic studies, a dissociation constant of 0.11 +/- 0.04 microM was calculated for the binding of protein Z to alpha-thrombin. Protein Z bound to large phospholipid vesicles (25% phosphatidylserine, 75% phosphatidylcholine) with a dissociation constant of 0.39 +/- 0.16 microM at a phospholipid to protein ratio of 82 mol of phospholipid/mol of protein Z at saturation. In the presence of protein Z thrombin associated with phospholipid vesicles, whereas thrombin did not interact with phospholipid vesicles in the absence of protein Z. These studies, therefore, demonstrate a physiologically relevant interaction between protein Z and thrombin. They also suggest a mechanism whereby thrombin is localized to an injury site by virtue of its interaction with protein Z bound to phospholipid surfaces.
 ...
PMID:Interaction of vitamin K-dependent protein Z with thrombin. Consequences for the amidolytic activity of thrombin and the interaction of thrombin with phospholipid vesicles. 204 Jun 12

Protein C is a hepatic vitamin K-dependent protein which on activation, inhibits activated factor V and VIII and involves fibrinolytic activity. Protein C deficiency is associated with increased risk of thromboembolic complications. The article presents a family with hereditary protein C deficiency and discusses information concerning and follow-up of the family members.
 ...
PMID:[Familial protein C-deficiency--a clinical presentation]. 204 35

A 54-year-old male patient with heterozygous Protein C deficiency associated with the nephrotic syndrome and deep femoral artery thrombosis is described. He was admitted to the hospital because of nephrotic syndrome. A few days later, severe pain appeared in his left leg and a diagnosis of deep femoral artery thrombosis was made. Thrombectomy was performed immediately. His proteinuria disappeared in response to corticosteroid. He was found to have Protein C deficiency, antigen: 44%, activity 31%, which was also present in his father and son. Digital subtraction angiography (DSA) revealed the obstruction of left internal iliac and deep femoral arteries at their origins. Renal and hepatic biopsy revealed minor glomerular abnormalities, and chronic active hepatitis. The presence of heterozygous Protein C deficiency, nephrotic syndrome and chronic active hepatitis seem to cause marked decrease in serum Protein C level and deep femoral artery thrombosis. He is now under successful control with warfarin (1.7 mg/day) and bucolome (300 mg/day). It was reported that Protein C might have a suppressive effect on hypercoagulability in nephrotic syndrome. Therefore, Protein C deficiency may not counteract the hypercoagulable state and promote thrombus formation in the case. The present report is the first of a case of Protein C deficiency associated with nephrotic syndrome and arterial thrombosis.
 ...
PMID:[A case of heterozygous protein C deficiency associated with nephrotic syndrome and deep femoral artery thrombosis]. 206 19

Every thromboembolic manifestation, especially in young subjects, calls for an aetiological study in which haemostasis is evaluated primarily with assays of physiological coagulation inhibitors: protein C, protein S and antithrombin III. Protein C deficiency is found in 6 to 7% of thromboembolic manifestations. We report the case of a 21-year old man who had phlebitis followed by pulmonary embolism without facilitating factors. Protein C level was 50% of normal value (0.50 IU/ml). The patient received heparin, subsequently replaced by oral anticoagulants after a long period of overlap between the two treatments. The outcome was favourable. Family investigation yielded a history of thromboembolic accidents in several members of the family, some of whom were protein C deficient (50% of normal value). Protein C synthesis is vitamin K-dependent. Protein C deficiency is transmitted as an autosomal dominant trait. Normal values range from 0.65 to 1.35 IU/ml. Clinically, 25% of the patients are said to be asymptomatic. The first thrombotic accidents occur in young subjects (mean age 29 +/- 14 years). Several points emerge from this case: full evaluation must be performed, especially in young subjects; family investigation consolidates the diagnosis and enables symptomatic protein C deficient patients to be treated and thrombotic manifestations to be prevented by effective anticoagulant therapy in high-risk situations; a prolonged period of heparin-oral anticoagulant overlap is needed to avoid cutaneous necrosis.
 ...
PMID:[Recurrent thromboembolism disclosing protein C deficiency. Apropos of a case with familial investigation]. 207 65

Little is known about the possible interrelationships between thrombin-induced EDRF-dependent vascular relaxation and coagulant activity. We have now studied the effects of the anticoagulant zymogen protein C, on EDRF-dependent relaxation in isolated canine coronary arteries. Low concentrations of activated protein C (0.1-30 ng/ml) had no significant effect, but higher concentrations caused relaxation (Emax -39.2 +/- 7.2%; 100-1000 ng/ml). To determine whether relaxation was dependent on coagulation complexes associated with endothelial cell membranes, the coumarin, brodifacoum was given three days before in vitro experiments were carried out in order to inhibit production of active vitamin K1-dependent clotting factors. Brodifacoum (10 mg/kg i.p.) increased prothrombin time from 8.5 +/- 0.24 sec (control), to 46.2 +/- 2.4 sec (p less than 0.05), but had no effect on thrombin-induced relaxation (Emax greater than 90%; ED50 0.026 +/- 0.004 units/ml control; 0.025 +/- 0.004 unit/ml brodifacoum). In the final group of studies, we investigated the effects of the concomitant administration of protein C (1000 ng/ml) and thrombin in vitro. Protein C (1000 ng/ml) increased relaxant sensitivity to thrombin after partial desensitization of the relaxant response by previous thrombin administration, (-60.2 +/- 7.1% thrombin alone; -77.9 +/- 7.2% thrombin + protein C), but had no effect after complete desensitization of the relaxant response. In conclusion, the data appear best explained by protein C and thrombin-induced EDRF dependent relaxation being due to proteolytic actions.
 ...
PMID:Investigation of the interrelationship between coagulation and thrombin-induced EDRF-dependent relaxation in dog coronary artery. 208 61

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.
 ...
PMID:Hereditary protein C deficiency: a review of the genetics, clinical presentation, diagnosis and treatment. 210 16

The pathogenesis of diabetic vasculopathy has been related to modifications in hemostasis and fibrinolysis. 50 non insulin dependent diabetes mellitus patients have been studied. Euglobulin clot lysis time, fibrin plate, tissue plasminogen activator (t-PA) antigen, plasminogen activator inhibitor (PAI) activity, Protein C and S, cholesterol, triglycerides and Hb A1c were determined in blood samples. Diabetic patients showed decreased fibrinolytic activity, as measured by ECLT, with clearly increased PAI levels. Fibrinolytic response to venous occlusion was lower than normal. Vascular complications were associated both with an even higher PAI activity and with a decreased fibrinolytic response to venous occlusion. Elevated PAI activity and decreased fibrinolytic response to stimulus may contribute to vascular disease in diabetes.
 ...
PMID:Hypofibrinolysis associated with vasculopathy in non insulin dependent diabetes mellitus. 211 76


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>