Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Physico-chemical characteristics of urokinase in urine were studied by immunological and chemical methods. By agar zone electrophoresis, commercial urokinase preparations could be separated into an anodic and cathodic fraction. The latter reacted with urokinase antibodies with two precipitation bands. Band I displayed the major part of urokinase activity and migrated as a beta-globulin with a molecular weight of 32,000 daltons. Band II showed immunological identity with human serum, human albumin, alpha-2-macroglobulin and alpha-2-HS-glycoprotein. The specific activity of the cathodic fractions was up to 80,000 ploug units/mg protein. The ratio esterase/fibrinolytic activity did not change during the purification procedure. Further purification of the fractions with higher specific activity by affinity chromatography was unable to eliminate material cross reacting with human antisera (Band II). These findings permit the conclusion, that urokinase activity in urine is not confined to a homogeneous protein fraction. Activity is found both in a low molecular weight fraction and in a high molecular weight complex which contains serum proteins. These cannot be removed by exhaustive purification procedures and may play an important role in stabilizing and/or protecting urinary urokinase against proteolytic degradation. With Todd's technique diffuse fibrinolytic activity could be demonstrated in the kidney in the iuxtamedullary border region, (venae arcuatae, venae interlobulares, vasa recta) and in the epithelium of the calyces. Urokinase activity was specifically blocked by highly purified urokinase antibodies and could thus be distinguished from nonspecific proteolytic activity. The topographic relationship to medulla and uroepithelium may point to a role of urokinase in maintaining patency in slow flow systems.
 ...
PMID:Isolation and renal localisation of urokinase. 10 50

Human blood monocytes in culture differentiate to macrophagelike cells within 1 week. Coinciding with this morphological transition the cells started releasing increasing amounts of the serine proteinase plasminogen activator (PA; Mr 56,000) of the urokinase (u-PA) type and the proteinase inhibitor alpha-2-macroglobulin (alpha 2M). Unlike the cell-associated PA activity, which was also readily detected in fresh monocytes, the activity secreted into the serum-free culture medium could be measured only after treatment of the samples with sodium dodecyl sulphate. Heat or acid treatment of the medium was not sufficient to reveal the PA activity, suggesting that, apart from alpha 2M, another PA-inhibiting substance was present in the culture medium. The inhibitor (Mr 65,000) was found to be synthesized by macrophages and specifically inhibited u-PA activity but not tissue-type PA (t-PA) or plasmin activity. Dexamethasone decreased the secretion of PA by differentiated macrophages without affecting the production of alpha 2M or the PA inhibitor. Dexamethasone also inhibited the morphological differentiation of the cells when added to the monocyte-phase cells.
 ...
PMID:Urokinase-type plasminogen activator and its inhibitor secreted by cultured human monocyte-macrophages. 257 31

In a prospective, randomized trial 33 patients with deep vein thrombosis were treated either with 2,200 or 1,100 IU/kg/h urokinase or with 100,000 IU/h streptokinase for at least 6 days. While streptokinase was given continuously, urokinase was administered intermittently (12 hr urokinase alternating with 12 hr heparin). Urokinase treatment resulted in a dose-dependent fibrinolytic state with shortening of the euglobulin clot lysis time, easily demonstrable amidolytic activity and moderate decrease of plasminogen. At the end of each urokinase-free interval the fibrinolytic activity had mostly faded, but was reproducibly elicited again by each new urokinase administration. Streptokinase immediately evoked the customary, intense fibrinolytic state, which progressively tapered off as plasminogen fell to 1% of its pretreatment concentration. In all treatment groups alpha-2-antiplasmin dropped to approximately 40% of its initial value during the first 12 hr with a further decrease to about 20% after 6 days. alpha-2-macroglobulin fell only moderately with either urokinase regimen, whereas it decreased progressively to 45% under streptokinase. While the fibrinolytic activity decreased under streptokinase over the 6-day infusion period, it appeared to increase with each successive urokinase infusion particularly with 1100 IU/kg/h. Thus the final euglobulin clot lysis times and the final fibrinogen concentrations were similar in all three treatment groups on the sixth day.
 ...
PMID:Systemic fibrinolytic activity and inhibitor levels during treatment of deep vein thrombosis with urokinase and streptokinase. 619 52

In the present paper we have characterized the plasminogen activators (PA) synthesized by 25 different human cell lines. Technically easy methods were adopted for concentration and immunological characterization of the activators even in the presence of PA inhibitors. Most cell lines produced u-PA (mol. wt 55,000), melanoma and HeLa cells t-PA (mol. wt 66,000) and two carcinoma cell lines and normal skin fibroblasts produced no detectable PA. The classical 125I-fibrin method was compared to a caseinolytic assay and some of the discrepancies between results obtained with the two methods were shown to be due to cell-derived NaDodSO4-sensitive proteinase inhibitors in culture media. Additionally, synthesis and uptake by the cells of the wide-spectrum proteinase inhibitor alpha-2-macroglobulin ( alpha 2M ) were studied by radioimmunoassay and immunofluorescence. No production of alpha 2M could be measured in any of the malignant cell lines. In normal cells no correlation existed between the production of alpha 2M and the observed inhibition of PA activity, which indicates that other proteinase inhibitors are produced by the cells.
 ...
PMID:Plasminogen activators, activation inhibitors and alpha 2-macroglobulin produced by cultured normal and malignant human cells. 620 45

Second trimester amniotic fluid fibrinolytic system was examined in normal pregnancies and those complicated by anencephaly, spina bifida and fetal chromosome abnormalities. No significant difference was demonstrated between the fibrinolytic systems from normal pregnancies and those complicated by fetal chromosome abnormalities. In pregnancies complicated with anencephaly and spina bifida no significant difference was demonstrated for alpha-1-antitrypsin, alpha-1-antichymotrypsin and urokinase. Plasminogen was significantly lower (p less than 0.02) and plasmin significantly higher (p less than 0.001) than levels from normal amniotic fluid. Alpha-2-macroglobulin, fibrinogen, FDP-D and FDP-E were detected only in pregnancies complicated with anencephaly and spina bifida.
 ...
PMID:Amniotic fluid fibrinolytic system in fetal neural tube defects. 635

To understand the contribution of epidermal melanocytes in the proteolytic potential of human skin, we have studied melanocytes grown in a low-serum medium deprived of phorbol esters, cholera toxin, and other non-physiological supplements. We focused on the plasminogen activation system and certain matrix metalloproteinases (gelatinases). Supposing that the proteolytic activity of cells can influence binding to collagen matrix and its reorganization, we have analyzed these parameters as well. We found that human melanocytes secreted tissue-type plasminogen activator and utilised it to generate cell-bound plasmin. No urokinase-type plasminogen activator was detected in the cultures but its receptor was found in cell extracts. Both the 72 kDa and 92 kDa gelatinases were secreted by the cells and in equal amounts. In addition, melanocytes secreted the wide-spectrum proteinase inhibitor alpha-2-macroglobulin. Melanocytes cast into collagen matrices retained a rounded morphology, did not extend processes, and were unable to contract collagen lattices. As a control, these parameters were investigated in parallel in cultures of human keratinocytes, dermal fibroblasts, and two melanoma cell lines. The obtained characteristics suggest that normal human melanocytes are proteolytically active cells. This function may pertain to skin physiology and pathophysiology.
 ...
PMID:The proteolytic potential of normal human melanocytes: comparison with other skin cells and melanoma cell lines. 901 12

Expression of proteolytic parameters of the urokinase-type plasminogen activator (uPA) system [uPA receptor (uPA-R), plasminogen activator inhibitor (PAI)-1] has been proven to be an independent prognostic parameter in cancer. However, it has not been considered that the uPA system is interacting with several other protease/inhibitor systems, neither has a comparable prognostic role of these factors been investigated. Moreover, studies evaluating specific protease patterns indicating high individual risk are missing completely. Therefore, in a consecutive prospective series of 203 gastric cancer patients, the expression of activators (plasminogen, tPA, MMP-2, cathepsin D, antithrombin 3) and inhibitors (alpha-2-antiplasmin, alpha-2-macroglobulin, alpha-1-antitrypsin, alpha-1-antichymotrypsin) of proteolysis was studied immunohistochemically in the tumor epithelium semiquantitatively (score 0-3) in addition to the uPA system. Kaplan-Meier analysis (median time of follow-up 31 months) revealed a significant association of cathepsin D (P=0.0042), alpha-2-macroglobulin (P=0.0281) and antitrypsin (P=0.0372) with disease-free survival and of cathepsin D (P=0.0018), antitrypsin (P=0.0112) and antichymotrypsin (P=0.0002) with overall survival. Multivariate Cox analysis performed to correct these results for relative impact of the uPA system and established prognostic factors showed PAI-1 (disease-free survival: P=0.002, relative risk 1.86; overall survival: P=0.005, relative risk 1.39), pT and pN as independent parameters. Cathepsin D was shown to have an independent impact on disease-free survival (P=0.020, relative risk 2.98). Comparative chi-square analysis of cases with poor and good prognoses revealed that in patients with good clinical outcome, inhibitors of proteolysis are correlated significantly, whereas in patients with poor prognosis activators of proteolysis are significantly associated preferentially and significant correlations with the uPA-R are dominant. For detailed pattern analysis, stepwise overall Kaplan-Meier analyses were performed in subgroups of high uPA-R-, uPA-, PAI1- and cathepsin D expression for two additional proteases each. From these analyses, the combination of high (score 2/3) expression of uPA-R, PAI-1, antichymotrypsin and alpha-2-macroglobulin was identified as a high-risk pattern, representing parameters known to be essential for uPA-R internalization and recycling. This suggests some of the uPA-associated proteases and inhibitors investigated as univariate prognostic parameters in gastric cancer. Cathepsin D is a new independent parameter for disease-free survival. The study further demonstrates that a protease pattern promoting uPA-R recycling in tumor cells especially indicates high individual risk tumors in gastric cancer.
 ...
PMID:Tumor-associated proteases and inhibitors in gastric cancer: analysis of prognostic impact and individual risk protease patterns. 950 78