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)

Desmopressin (DDAVP) 0.3 micrograms/kg was administered intravenously to three normal volunteers and 12 patients with von Willebrand's disease (vWD), congenital or acquired platelet function defect, or uremic bleeding to assess its effects and side effects. DDAVP significantly shortened the bleeding time as compared with basal values. The mean peak post-DDAVP level of factor VIII coagulant activity increased 5.9 +/- 0.5 (mean +/- SEM) fold, von Willebrand factor antigen increased 3.7 +/- 0.3 fold, von Willebrand factor ristocetin cofactor activity increased 4.6 +/- 0.6 fold and the tissue-type plasminogen activator antigen increased 3.4 +/- 0.6 fold. Analysis of the multimeric structure of the von Willebrand factor revealed that type I vWD had complete correction after DDAVP infusion transiently. Except for a mild drop in both systolic and diastolic blood pressures, few side effects were noted. By concomitant intravenous infusion of DDAVP and oral administration of tranexamic acid, we successfully treated two cases of type I vWD undergoing tooth extraction, and one case of acquired bleeding disorder undergoing a biopsy of a mandibular mass, and a uremic patient complicated by intractable traumatic hematuria. Our experiences confirmed that most patients with vWD and some patients with congenital or acquired bleeding disorders can be treated effectively by DDAVP infusion without the need for plasma product replacement. In this study we found that a patient with a variant form of type I vWD had prolongation of the bleeding time, thrombocytopenia and platelet aggregation after DDAVP infusion.
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PMID:Experience of desmopressin (DDAVP) administration in patients with congenital and acquired bleeding disorders. 136 75

In order to clarify the effect of hemodialysis (HD) on the fibrinolytic system, fibrinolytic activity was evaluated in 27 patients undergoing regular hemodialysis treatment (RDT) using new parameters including plasma alpha 2-plasmin inhibitor (alpha 2 PI), alpha 2-plasmin inhibitor-plasmin complex (alpha 2 PIC), cross-linked fibrin degradation products (XL-FDP), tissue plasminogen activator (t-PA) activity, t-PA antigen and plasminogen activator inhibitor-1 (PAI-1) antigen. Predialysis baseline levels of plasminogen and alpha 2PI activity in RDT patients were significantly lower and those of alpha 2PIC were significantly higher than normal control values. During a single HD session, alpha 2PIC exhibited a continuous, significant increase reaching about 180% of initial values by the end of HD. alpha 2PI activity was significantly decreased at the end of the HD, though there were no significant changes in plasminogen activity during HD. Predialysis baseline levels of XL-FDP in RDT patients were significantly higher than normal control values. No significant changes in XL-FDP were observed during HD. Both t-PA activity and t-PA antigen significantly increased during HD, and PAI-1 antigen significantly decreased during HD. Von Willebrand factor (vWF) antigen in plasma, which is regarded as reflecting a release reaction by vascular endothelial cells to certain stimuli, also significantly increased during HD. However, neither vWF antigen nor t-PA antigen was increased by heparin administration alone. The changes in alpha 2PI and alpha 2PIC levels suggest that fibrinolytic activity is slightly higher in RDT patients and is even higher during HD.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enhanced fibrinolytic activity during the course of hemodialysis. 138 98

When patients with mild haemophilia or von Willebrand disease (vWD) are repeatedly treated with desmopressin (DDAVP) at relatively short time intervals, some of them may become less responsive or unresponsive. The development of tachyphylaxis would limit the usefulness of DDAVP in clinical management of these patients. On the other hand, tachyphylaxis is not consistent, and its patterns of development are unknown. The aim of this study was to evaluate in controlled conditions the occurrence of tachyphylaxis by giving intravenous DDAVP (0.3 microgram/kg) on four consecutive days to a selected group of patients with mild haemophilia A (n = 22) and type I vWD (n = 15). After each dose, we measured parameters known to change after DDAVP, i.e. factor VIII coagulant activity, bleeding time, von Willebrand factor antigen, ristocetin cofactor and tissue-type plasminogen activator antigen. We found that on average the responses obtained after the second dose of DDAVP were approximately 30% less than those obtained after the first, but were not further reduced after the third and fourth dose. At all time intervals after DDAVP, patients with vWD responded relatively better than patients with haemophilia, and there were fewer vWD patients who responded poorly or became unresponsive. In vWD patients there were no significant changes in the bleeding time responses and in blood pressure and heart rate. The clinical implications of these findings are that repeated doses of DDAVP can be given efficaciously to many patients (particularly to those with vWD), even though responses lower than those seen after the first dose should be expected.
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PMID:Patterns of development of tachyphylaxis in patients with haemophilia and von Willebrand disease after repeated doses of desmopressin (DDAVP). 141 7

Nine healthy volunteers and 23 patients with various types of von Willebrand disease were studied before and after DDAVP infusion. We investigated the behaviour of factor VIII/von Willebrand factor measurements, and of tissue plasminogen activator and urokinase-type plasminogen activator. In mild von Willebrand disease the increase of both plasminogen activators was similar to that seen in normal controls. A different fibrinolytic behaviour was found in the type I platelet low and in the type III von Willebrand disease patients. An impaired and absent fibrinolytic response to DDAVP was seen in the former and in the latter von Willebrand disease, respectively. A close relation between either u-PA and t-PA or von Willebrand factor was observed. The possibility of a linkage among these three proteins was discussed.
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PMID:Urokinase-type plasminogen activator release after DDAVP in von Willebrand disease: different behaviour of plasminogen activators according to the synthesis of von Willebrand factor. 152 8

The mesothelial cells obtained from human omental adipose tissue showed a typical cobblestone monolayer and reacted strongly with keratin, but did not have Von Willebrand factor. Ultrastructurally these cells revealed the existence of desmosome-like cell junctions as well as intracellular canaliculi, tubular structures surrounded by microvilli, and tonofilament-like filaments. The mesothelial cells grew much faster in the medium containing epidermal growth factor, actively took up acetylated-low density lipoprotein into their cytoplasm, and released angiotensin-converting enzyme. They also released urokinase-type plasminogen activator, but only half as much as do human umbilical vein endothelial cells; release of tissue-type plasminogen activator was not observed. Inasmuch as the mesothelial cells also released plasminogen activator inhibitor-1, as do human umbilical vein endothelial cells, we could not detect u-PA activity in culture medium. u-Pa may play a role in the protection against adhesion among visceral organs. These observations indicate that cultured human mesothelial cells have characteristics closely related to those found in human endothelial cells.
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PMID:Close similarity between cultured human omental mesothelial cells and endothelial cells in cytochemical markers and plasminogen activator production. 171 52

The fibrinolytic response to venous occlusion was studied in 17 patients with inflammatory bowel disease: 7 with Crohn's disease, 10 with ulcerative colitis and compared with those obtained in 20 controls. Patients with inflammatory bowel disease showed decreased tissue-type plasminogen activator antigen release (t-PA Ag), no significant Von Willebrand antigen release (vWF Ag), and a residual plasminogen activator inhibitor activity (PAI activity) after venous occlusion. These modifications were more important in the evolutive colitis group compared with the remission group. Hypofibrinolysis, as defined by a defective t-PA release, and a residual PAI activity after venous occlusion might contribute to digestive and/or extra digestive thrombotic manifestations observed during the course of inflammatory bowel diseases.
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PMID:[Impaired fibrinolytic response to the venous occlusion test in patients with cryptogenic colitis]. 178 49

The physiologic mechanisms that influence plasma levels of von Willebrand factor (vWF) are poorly understood but include race, blood group, age, pregnancy, exercise, and adrenergic and neurohumoral stimuli. Inherited abnormalities in von Willebrand's disease (vWD) are associated with a defect of the vWF gene on chromosome 12, but in some cases, coexistence of impaired response of plasminogen activator and telangiectasia suggests the presence of a regulatory defect or more extensive endothelial perturbation. Three broad types of vWD are recognized; in addition, a platelet-type vWD (pseudo-vWD) is due to an abnormal platelet receptor for vWF. The prevalence of vWD, which is difficult to determine because of variations in severity even within a kindred, is reportedly as high as 1%. In a survey of European patients, the prevalence of treated vWD varied from 4.5 to 24 per million. Preliminary results of an international survey of vWD indicate that about 3% of treated patients have seroconversion to human immunodeficiency virus, 50% of whom have symptoms. Inhibitor of vWF occurs in type III vWD after treatment and is associated with the presence of gene deletions. Acquired vWD may complicate lymphoproliferative and autoimmune disorders, and proteolytic degradation of vWF complicates myeloproliferative disorders. The level of vWF is increased during pregnancy and in vascular and other disorders; it may be involved in the pathogenesis of atherosclerosis. High-molecular-weight multimers of vWF and a cofactor are thought to promote the formation of microthrombi in thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome. Thus, study of vWD has shed light on pathogenetic mechanisms in a wide range of disorders.
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PMID:von Willebrand factor: clinical features of inherited and acquired disorders. 207 62

The nature, mechanism of action, and roles of endothelium-derived relaxant factor (EDRF) are reviewed, particularly in relation to the coordination of vascular behavior in response to changes in flow, coronary spasm, and platelet aggregation. Vascular endothelium performs a multiplicity of roles. It is an active sieve for macromolecules and leukocytes, a negatively charged "lubricant" for passage of negatively charged red cells and platelets, and a factory for Von Willebrand factor, glycoaminoglycans, and plasminogen activator and its inhibitor. It is also a processing plant that metabolizes adenosine nucleotides to adenosine and activates angiotensin. Endothelium also produces prostacyclin and endothelium-derived relaxant factor, which act synergistically and through different pathways to the common ends of relaxing vascular smooth muscle and inhibiting platelet aggregation. Most recently it has been shown to also produce a constrictor agent called endothelin, a peptide whose structure has now been elucidated. This review will concentrate on EDRF, the recently discovered vasodilator agent that is continuously released by all vascular endothelium. It would be premature to define the role of EDRF in ischemic heart disease. It may, however, be timely to consider the ways in which EDRF might be relevant, based on a review of what is at present known.
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PMID:Vascular endothelium in ischemic heart disease: possible role for endothelium-derived relaxing factor. 248 97

Nine patients with, and 11 without, venous thromboses (DVT) from two families were studied. In family 1, four members with, and one without, DVT had t-PA activity below the lower limit of the controls (21.3 IU/ml, n = 19) after 20 min venous occlusion (VO). After VO t-PA antigen (t-PA:Ag) was below the lowest value of the controls (22.8 ng/ml) in all five cases with low t-PA activity. All the family members, both with and without thrombosis, had normal t-PA inhibitor activities (PAI). In family 2 t-PA activity after VO was low in three symptomatic and four asymptomatic family members. t-PA:Ag was also low in four of these. PAI level was normal in all but one family member. Mild type I von Willebrand's disease was discovered in four members of family 2. Deficient t-PA:Ag response was found in two of these. Antithrombin III, protein C and protein S were normal in both families. It is concluded that low fibrinolytic capacity, independent of PAI, is associated with familial DVT. Our data suggests autosomal dominant inheritance.
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PMID:Familial hypofibrinolysis and venous thrombosis. 249 18

Desamino-D-arginine vasopressin (DDAVP) is known to stimulate factor VIII (FVIII) and plasminogen activator release from endothelial cells, and has been shown to stimulate prostacyclin (PGI2) production in normal and haemophilic subjects. In von Willebrand's disease (vWd) some patients have a dissociate response with regard to FVIII and plasminogen activator. The aim of our study was to compare the PGI2, FVIII and plasminogen activator response to DDAVP infusion in vWd with the response to DDAVP in normal and haemophilic subjects. PGI2 metabolites thromboxane B2 (TxB2), factor VIII coagulant activity, factor VIII-related antigen and plasminogen activator were measured before and after DDAVP infusion. There was a significant increase in PGI2 metabolites, factor VIII-related antigen and plasminogen activator in all groups following DDAVP, but no effect on TxB2 was found, and there was no evidence of any dissociate response to DDAVP in any of the groups. Basal levels of PGI2 metabolites, however, were significantly lower in vWd as compared to normal and haemophilic subjects. Post-DDAVP levels of PGI2 metabolites were also significantly lower in vWd as compared with normal subjects. This may be due to a reduced stimulus to PGI2 production in vWd secondary to defective platelet adhesion.
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PMID:Endothelial stimulation by DDAVP in von Willebrand's disease and haemophilia. 308 64


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