Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.108 (TAT)
 2,389 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was designed to elucidate the participation of endothelin-1(ET-1) in vivo and in vitro coagulation. The microvascular hemodynamic changes in terms of intravascular thrombus formation in rat mesentery induced by the superfusion of ET-1 (0.5, 1 and 2 pmol) were visualized by an intravital microscope system assisted by television-video tape recorder system. In addition to vasoconstriction we observed the blockade of circulation by clumps resembling thrombus in a dose dependent fashion by ET-1. Thrombus formation could be attenuated by pretreatment with superfusion of 3.8% Na citrate solution but not by the prior superfusion of 1 to 3 ng of nitroglycerine. Thrombus formation was found after the administration of 10 microliters of CaCl2 (100 nM) solution in Na citrate (3.8%, 20 microliters) and ET-1 treated field. In vitro study, a dose dependent increase in TAT (thrombin-antithrombin complexes) and decrease in AT III (antithrombin III) (%) activity, the prolongation of PT (prothrombin time) and APTT (activated partial thromboplastin time) was found by administering ET-1 immediately in native (unanticoagulated) blood in silicon coated test tubes (p < 0.05; n = 6). However in citrated blood, TAT complexes, AT III (%) activity, PT and APTT were not significantly changed after administration of the same doses of ET-1 (p > 0.05; n = 6). Therefore, this study suggested that endothelin-1 caused intravascular thrombosis and enhanced intra test tube coagulation which could be attenuated by blocking ionic calcium.
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PMID:Coagulation in vivo microcirculation and in vitro caused by endothelin-1. 830 59

After high-voltage electric injury, patients often show tissue necrosis and thrombosis of blood vessels even remote from entry and exit site of electrical current. In this study, plasma levels of TAT, F(1+2), PAI-1, and t-PA were determined in vivo in three patients with high-voltage injury for 96 hours after trauma. In order to analyse a possible effect on haemostasis related to endothelial cell damage, protein S, TF, ET-1, PGI(2), NO, t-PA, and PAI-1 were determined for 72 hours in vitro in cell culture supernatant of HUVECs that had been exposed to 1, 10, 30, and 50 electric field periods of 50 Hz with field strength of 60 V/cm and duration of 20 ms. Furthermore, expression of thrombomodulin was immunohistochemically analysed. Clotting activation could be observed in our patients by increased levels of F(1+2) and TAT between 12 and 72 hours after injury, whereas fibrinolysis was disturbed due to high PAI-1. One patient presented thrombosis of vessels by day 3. In vitro, PAI-1 increased significantly (p<0.05) in medium of cells with an application of 30 and 50 periods between 2 and 48 hours. Between 4 and 72 hours, the concentration of t-PA was significantly lower (p<0.05) in the medium of HUVECs exposed to 10, 30, and 50 periods, whereas there was a significant increase (p<0.05) in the concentration of TF in the cell groups with an application of 30 and 50 periods. 24, 48, and 72 hours after injury, there was just weak or no staining for thrombomodulin in HUVECs with an application of 30 and 50 periods. The disturbed balance between clotting system and fibrinolysis seen in vitro after electric injury might explain the clinical observation of a progressive thrombosis of blood vessels after electric injury leading to tissue loss.
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PMID:Influence of low frequency electric fields on anti- and pro-coagulability of the vascular endothelium: new insights into high-voltage electrical injury. 1511 62

Imaging of specific intracellular target proteins in living cells has been of great challenge and importance for understanding intracellular events and elucidating various biological phenomena. Highly photoluminescent and water-soluble semiconductor nanocrystal quantum dots (QDs) have been extensively applied to various cellular imaging applications due to the long-term photostability and the tunable narrow emission spectra with broad excitation. Despite the great success of various bioimaging and diagnostic applications, visualization of intracellular targets in live cells still has been of great challenge. Nonspecific binding, difficulty of intracellular delivery, or endosomal trapping of nanosized QDs are the main reasons to hamper specific target binding in live cells. In this context, we prepared the polymer-coated QDs (pcQD) of which the surface was optimized for specific intracellular targeting in live cells. Efficient intracellular delivery was achieved through PEGylation and subsequent cell penetrating peptide (i.e., TAT) conjugation to the pcQD in order to avoid significant endosomal sequestration and to facilitate internalization of the QDs, respectively. In this study, we employed HEK293 cell line overexpressing endothelin A receptor (ET(A)R), a family of G-protein coupled receptor (GPCR), of which the cytosolic c-terminal site is genetically engineered to possess green fluorescent protein (GFP) as our intracellular protein target. The fluorescence signal of the target protein and the well-defined intracellular behavior of the GPCR help to evaluate the targeting specificity of QDs in living cells. To test the hypothesis that the TAT-QDs conjugated with antibody against intracellular target of interest can find the target, we conjugated anti-GFP antibody to TAT-PEG-pcQD using heterobifunctional linkers. Compared to the TAT-PEG-pcQD, which was distributed throughout the cytoplasm, the antiGFP-functionalized TAT-PEG-pcQD could penetrate the cell membrane and colocalize with the GFP. An agonist (endothelin-1, ET-1) treatment induced GFP-ET(A)R translocation into pericentriolar region, where the GFP also significantly colocalized with antiGFP-TAT-PEG-pcQD. These results demonstrate that stepwise optimization of PEG-pcQD conjugation with both a cell penetrating peptide and an antibody against a target of interest allows specific binding to the intracellular target protein with minimized nonspecific binding.
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PMID:Intracellular protein target detection by quantum dots optimized for live cell imaging. 2171 16