Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to obtain selective suicide substrates of trypsin-like proteases including plasminogen activators, plasmin, and thrombin, a series of cyclopeptides cyclo[Arg or Lys-aB(CH2X)-Gly4], in which a substituted o- or m-aminobenzoyl group constitutes a latent electrophile, have been prepared. Treatment of the corresponding phenyl ethers cyclo[P1-aB(CH2OC6H5)-Gly4] with HBr/HOAc or R1R2S/TFA gives the bromides (X = Br) or the sulfonium salts (X = +SR1R2 with R1 = R2 = Me or R1 = Me and R2 = C6H5), respectively. These water-soluble cyclopeptides behave as time-dependent inhibitors of bovine trypsin and human urokinase (u-PA) but have no effect on tissue plasminogen activator (t-PA) and no or poor effect on plasmin and thrombin. The compounds containing a m-aminobenzoic acid residue are more efficient inactivators than their anthranilic analogues. The kinetic criteria expected for a suicide inhibition are met. A mechanism of inhibition involving the formation of a quinonimmonium methide intermediate is proposed. The activity of the inhibitors is very sensitive to the nature of the X benzylic substituent. An increased efficiency for the inactivation of human urokinase is observed with the sulfonium salts. The selectivity of the inactivation of u-PA compared to t-PA could be of therapeutical significance in controlling cell proliferation and invasion.
...
PMID:New mechanism-based inactivators of trypsin-like proteinases. Selective inactivation of urokinase by functionalized cyclopeptides incorporating a sulfoniomethyl-substituted m-aminobenzoic acid residue. 849 23

A method for the localization of activities of proteases using substrates with 7-amino-3-trifluoromethylcoumarine (AFC) leaving group is described. 0.1 ml of 5-20 mMol solution of the respective substrate (Gly-Pro-AFC, Ala-Pro-AFC, Z-Ala-Arg-Arg-AFC, Z-Gly-Arg-Arg-AFC, Z-Gly-Gly-Arg-AFC, D-Val-Leu-Lys-AFC) in dimethylsulfoxide or dimethylformamide was added to 0.9 ml of 0.1 M Tris-HCl buffer, pH 7.4-7.8 or 0.1 M cacodylate buffer, pH 5-5.5. In the case of Z-Ala-Arg-Arg-AFC (cathepsin B substrate) 15 mM EDTA and 12 mM dithiothreitol were added. 7 mM amiloride or 2 mg/1 ml aprotinin were used as inhibitors with Z-Gly-Gly-Arg-AFC (urokinase substrate) and with D-Val-Leu-Lys-AFC (plasmin substrate). Substrate solutions were mixed with an equal amount of 2% agar solution in distilled water or in the respective buffer the pH of which was adjusted according to the pH optimum of the enzyme to be demonstrated. The agar solution was kept in a water bath at a temperature of 50-60 degrees C. After careful mixing, the substrate solution in agar was poured into a cylindrical vessel closed with a semipermeable membrane (Nephrophan) on which unfixed cryostat sections were mounted. 1-5 mM AFC solution in dimethylsulfoxide or dimethylformamide instead of the substrate was used as the control. Quenched samples of rat kidney and jejunum, biopsies of human jejunal mucosa, and of colorectal and uterine tumors were employed for the preparation of sections. After gelification of the medium in a refrigerator the vessels with sections were incubated in the dark at 37 degrees C for 0.5-several h. The reaction was controlled in a fluorescence microscope with an epiillumination adjusted to the FITC fluorescence and documented. A yellowish green fluorescence depicts sites where AFC was set free (sites with enzyme activity). When the reaction reached the required intensity the membranes were cut off, transferred to glass slides, mounted in glycerol, observed and photographed immediately (due to the solubility of AFC in glycerol). An acceptable cellular localization was achieved. The method with AFC substrates can be recommended for comparative biochemical and histochemical studies of proteases using the same substrate and for cases in which no other reliable procedure for the localization of the respective enzyme activity is available (e.g. urokinase, plasmin).
...
PMID:The use of substrates with 7-amino-3-trifluoromethylcoumarine (AFC) leaving group in the localization of protease activities in situ. 873 6

The mouse is the most commonly used species for in vivo studies on angiogenesis related to tumor development. Yet, to the best of our knowledge, very few reports on the in vitro interaction of the angiogenic basic fibroblast growth factor (bFGF) with mouse endothelial cells are available. Three mouse endothelial cell lines originated from aorta (MAECs), brain capillaries (MBECs), and heart capillaries (MHECs) were characterized for endothelial phenotypic markers, in vivo tumorigenic activity, and the capacity to respond in vitro to bFGF. These cells express angiotensin-converting enzyme, acetylated LDL receptor, constitutive endothelial nitric oxide synthase, and vascular cell adhesion molecule-1 and bind Griffonia simplicifolia-I lectin. When injected subcutaneously in nude mice, MAECs induced the appearance of slow-growing vascular lesions reminiscent of epithelioid hemangioendothelioma, whereas MBEC xenografts grew rapidly, showing Kaposi's sarcoma-like morphological features. No lesions were induced by injection of MHECs. MAECs, MBECs, and MHECs expressed both low-affinity heparan sulfate bFGF-binding sites and high-affinity tyrosine kinase receptors (FGFRs) on their surfaces. In particular, MAECs expressed FGFR-2/bek mRNA, whereas microvascular MBECs and MHECs expressed FGFR-1/flg mRNA. Accordingly, bFGF induced a mitogenic response and the phosphorylation of extracellular signal-regulated kinase-2 in all the cell lines. In contrast, upregulation of urokinase-type plasminogen activator expression was observed in bFGF-treated microvascular MBECs and MHECs but not in MAECs. Also, bFGF-treated MBECs and MHECs but not MAECs invaded a three-dimensional fibrin gel and formed hollow, capillary-like structures. The relevance of the modifications of the fibrinolytic balance of mouse microvascular endothelium in bFGF-induced angiogenesis was validated in vivo by a gelatin-sponge assay in which the plasmin inhibitors tranexamic acid and epsilon-aminocaproic acid given to mice in the drinking water inhibited neovascularization induced by the growth factor. In conclusion, differences in response to bFGF exist between large-vessel MAECs and microvascular MBECs and MHECs. Both in vitro and in vivo data point to a role of the profibrinolytic phenotype induced by bFGF in microvascular endothelial cells during mouse angiogenesis. Our observations make these endothelial cell lines suitable for further studies on mouse endothelium during angiogenesis and in angioproliferative diseases.
...
PMID:Basic fibroblast growth factor-induced angiogenic phenotype in mouse endothelium. A study of aortic and microvascular endothelial cell lines. 910 63

Clinical worsening often occurs 1 to 2 days after an intracerebral hemorrhage. Extracellular matrix proteolysis by metalloproteinases, which attack the basal lamina and open the blood-brain barrier, may be one contributing factor. Matrix metalloproteinases and plasminogen activators are increased 16 to 24 hours after a bacterial collagenase-induced intracerebral hemorrhage, suggesting that agents that block metalloproteinases may reduce the brain swelling after hemorrhage. Therefore, we injected 0.2, 0.3, 0.4, or 0.5 units bacterial collagenase intracerebrally in rats to produce an intracerebral hemorrhage. Twenty-four hours later, brain tissue was removed for measurement of brain water and electrolytes. Proteases were assayed by zymography. Treatment with a matrix metalloproteinase inhibitor, BB-1101, was begun 6 hours after the collagenase lesion, when the hematomas were formed and the secondary edema was increasing. Bacterial collagenase caused a dose-dependent hematoma at the injection site with secondary brain edema in both posterior regions. The lower bacterial collagenase doses (0.2 and 0.3 units) mainly caused brain edema in the tissue around the injection site, whereas the higher doses (0.4 and 0.5 units) also affected the opposite hemisphere. Administration of BB-1101 significantly reduced the brain water and sodium contents in regions away from the injection site in rats with 0.4 unit lesions (p < 0.05). Zymography showed an increase in 92-kDa type IV collagenase and urokinase-type plasminogen activator at 24 hours. Inhibitors of proteolytic cascade enzymes may be useful in treatment of secondary brain edema in intracerebral hemorrhage.
...
PMID:Metalloproteinase inhibition blocks edema in intracerebral hemorrhage in the rat. 910 78

Amiloride is an inhibitor of urokinase plasminogen activator (uPA), an essential component of the plasminogen/plasmin enzyme system. Inhibition of uPA prevents the conversion of plasminogen to tumor cell surface bound plasmin which is required for initiation of the metastatic process. MATB rat mammary cancer cells were introduced into the jugular venous system of 80 Fisher 344 female rats. Amiloride at high and low dosages was administered in the drinking water at the time of, prior to or several days following the tumor cell inoculation and continued daily for 10 days post inoculation. Control rats were maintained on water alone. The middle lobe of the right lung was examined microscopically for numbers of metastases. Suppression of metastases was significant at high amiloride dosages in all groups, and at low dosage when administered prior to inoculation. We conclude that amiloride suppresses induced metastases of rat mammary cancer, the effect being dose- and time-dependent.
...
PMID:Time and dose dependency of the suppression of pulmonary metastases of rat mammary cancer by amiloride. 962 14

Polymer conjugation is of increasing interest in pharmaceutical chemistry for delivering drugs of simple structure or complex compounds such peptides, enzymes and oligonucleotides. For long time drugs, mainly with antitumoral activity, have been coupled to natural or synthetic polymers with the purpose of increasing their blood permanence time, taking advantage of the increased mass that reduces kidney ultrafiltration. However only recently complex constructs were devised that exploit the 'enhanced permeability and retention' (EPR) effect for an efficient tumor targeting, the high molecular weight for adsorption or receptor mediated endocytosis and finally a lysosomotropic targeting, taking advantage of acid labile bonds or cathepsin susceptible polypeptide spacers between polymer and drug. New original, very active conjugates of this type, as those based on poly(hydroxyacrylate) polymers, are already in advanced state of development. Labile oligonucleotides, including antisense drugs, were also successfully coupled to polymers in view of an increased cell penetration and stabilization towards nucleases. However, the most active research activity resides in the field of polypeptides and proteins delivery, mainly for the two following reasons: first of all because a great number of therapeutically interesting compounds are now being produced by genetic engineering in large quantity and, secondly, because these products are difficult to administer to patients for several inherent drawbacks. Proteins are in fact easily digested by many endo- and exo-peptidases present in blood or in other body districts; most of them are immunogenic to some extent and, finally, they are rapidly excreted by kidney ultrafiltration. Covalent polymer conjugation at protein surface was demonstrated to reduce or eliminate these problems, since the bound polymer behaves like a shield hindering the approach of proteolytic enzymes, antibodies, or antigen processing cell. Furthermore, the increase of the molecular weight of the conjugate allows to overcome the kidney elimination threshold. Many successful results were already obtained in peptides and proteins, conjugated mainly to water soluble or amphiphilic polymers like poly(ethylene glycol) (PEG), dextrans, or styrenemaleic acid anhydride. Among the most successful are the conjugates of asparaginase, interleukin-2 or -6 and neocarcinostatin, to remind some antitumor agents, adenosine deaminase employed in a genetic desease treatment, superoxide dismutase as scavenger of toxic radicals, hemoglobin as oxygen carrier and urokinase and streptokinase as proteins with antithrombotic activity. In pharmaceutical chemistry the conjugation with polymers is also of great importance for synthetic applications since many enzymes without loss of catalytic activity become soluble in organic solvents where many drug precursors are. The various and often difficult chemical problems encountered in conjugation of so many different products prompted the development of many synthetic procedures, all characterized by high specificity and mild condition of reaction, now known as 'bioconjugation chemistry'. Bioconjugation developed also the design of new tailor-made polymers with the wanted molecular weight, shape, structure and with the functional groups needed for coupling at the wanted positions in the chain.
...
PMID:Bioconjugation in pharmaceutical chemistry. 1051 Aug 47

The retention of urokinase activity after frozen storage was studied. Urokinase powder was reconstituted aseptically in sterile water for injection or preservative-free 0.9% sodium chloride injection to a final concentration of 5000 IU/mL. Samples were stored in 5-mL plastic syringes at -20 or -70 degrees C for up to six months. Samples containing urokinase 25,000 IU/mL were similarly prepared by using sodium chloride injection as the diluent and were stored frozen at the same temperatures for up to 93 days. Urokinase activity was measured with a chromogenic assay at each test interval. Samples were also cultured after thawing to evaluate their potential to support microbial growth. The activity of urokinase at either concentration did not change appreciably during the study period. The method of thawing-at room temperature or in a refrigerator-had no effect on urokinase activity. No microbial growth was observed. Urokinase 5000 IU/mL did not show any changes in activity when reconstituted with sterile water for injection or 0.9% sodium chloride injection and frozen for up to six months. Urokinase 25,000 IU/mL in sodium chloride injection was also stable after 93 days of frozen storage.
...
PMID:Urokinase activity after freezing: implications for thrombolysis in intraventricular hemorrhage. 1054 Oct 31

Chronic, intermittent GI bleeding is defined as obscure when routine diagnostic examinations of the GI tract, including barium and endoscopic studies, fail to reveal the cause of bleeding. Our patient had significant bleeding and extensive evaluation including upper endoscopy, small bowel enteroscopy, enteroclysis, colonoscopy, and provocative angiography with urokinase, without the source of bleeding detected. This report describes a noninvasive novel approach using helical CT scanning with water as oral contrast and rapid injection of intravenous iodinated contrast material and thin slices obtained to diagnose the site of recurrent, obscure GI bleeding related to cholesterol crystal embolization to the small intestine.
...
PMID:Detection of bleeding due to small bowel cholesterol emboli using helical CT examination in gastrointestinal bleeding of obscure origin. 1060 30

Intrapleural administration of fibrinolytic agents such as urokinase (UK) has been advocated as an alternative method to manage complicated pleural effusion (CPE). Despite the increasing number of empyemas successfully treated with UK in adults, the experience in children is limited to a few cases. We report the results of image-guided catheter drainage (IGCD) with intracavitary instillation of UK in six children with CPE. Urokinase (25,000-100, 000 IU) was diluted in 20 mL of normal saline and instilled into the pleural cavity via a percutaneously placed drainage catheter. After 4 hr, the clamped catheter was released and connected to water-seal suction at a negative pressure of 20 cm H(2)O. UK instillation was repeated daily until no further drainage occurred. During IGCD, repeated radiographic and ultrasound imaging determined the location and amount of any remaining pleural fluid. Mean duration of hospital stay before initiating UK therapy was 4.3 days. Mean duration of catheter drainage before initiating UK therapy was 3.5 days, and the mean total drainage was 86 mL. All patients had an increase in chest tube drainage within 24 hr after the first instillation of UK. The mean net total drainage after UK instillation was 281 mL, most of the drainage being occurring in the first 2 days of treatment. Mean hospital stay following UK treatment was 5.8 days, and the average total duration of hospital stay was 13.8 days. No complications and no adverse events occurred during treatment with UK. Complete resolution of the consequences of the pleural effusion was observed in all patients at follow-up. Our results suggest that IGCD with adjunctive UK therapy is a reliable, simple, and safe approach to treat CPE, and it can reduce the risks associated with thoracotomy and decortication.
...
PMID:Treatment of complicated pleural effusion with intracavitary urokinase in children. 1082 25

The interaction of plasminogen, tissue plasminogen activator (t-PA) and urokinase with a clinical strain of Helicobacter pylori was studied. Plasminogen bound to the surface of H. pylori cells in a concentration-dependent manner and could be activated to the enzymatic form, plasmin, by t-PA. Affinity chromatography assays revealed a plasminogen-binding protein of 58.9 kDa in water extracts of surface proteins. Surface-associated plasmin activity, detected with the chromogenic substrate CBS 00.65, was observed only when plasminogen and an exogenous activator were added to the cell suspension. The two physiologic plasminogen activators, t-PA and urokinase, were also shown to bind to and remain active on the surface of bacterial cells. epsilon-Aminocaproic acid caused partial inhibition of t-PA binding, suggesting that the kringle 2 structure of this activator is involved in the interaction with surface receptors. The activation of plasminogen by t-PA, but not urokinase, strongly depended on the presence of cells and a 25-fold enhancer effect on the initial velocity of activation by t-PA compared to urokinase was established. Furthermore, a relationship between cell concentration and the initial velocity of activation was demonstrated. These findings support the concept that plasminogen activation by t-PA on the bacterial surface is a surface-dependent reaction which offers catalytic advantages.
...
PMID:A study of the interaction between Helicobacter pylori and components of the human fibrinolytic system. 1097 31


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

---