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

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thrombin-induced platelet microbicidal protein (tPMP-1) is a small, cationic peptide released from rabbit platelets exposed to thrombin in vitro. tPMP-1 is microbicidal against a broad spectrum of bloodstream pathogens, including Staphylococcus aureus. Preliminary evidence suggests that tPMP-1 targets and disrupts the staphylococcal cytoplasmic membrane. However, it is not clear if the cytoplasmic membrane is a direct or indirect target of tPMP-1. Therefore, we assessed the in vitro activity of tPMP-1 versus protoplasts prepared from logarithmic-phase (LOG) or stationary-phase (STAT) cells of the genetically related S. aureus strains 19S and 19R (tPMP-1 susceptible and resistant, respectively). Protoplasts exposed to tPMP-1 (2 microg/ml) for 2 h at 37 degrees C were monitored for lysis (decrease in optical density at 420 nm) and ultrastructural alterations (by transmission electron microscopy [TEM]). Exposure to tPMP-1 resulted in substantial lysis of LOG but not STAT protoplasts of 19S, coinciding with protoplast membrane disruption observed by TEM. Thus, it appears that tPMP-1-induced membrane damage is influenced by the bacterial growth phase but is independent of the staphylococcal cell wall. In contrast to 19S, neither LOG nor STAT protoplasts of 19R were lysed by tPMP-1. tPMP-1-induced membrane damage was further characterized with anionic planar lipid bilayers subjected to various trans-negative voltages. tPMP-1 increased conductance across bilayers at -90 mV but not at -30 mV. Once initiated, a reduction in voltage from -90 to -30 mV diminished conductance magnitude but did not eliminate tPMP-1-mediated membrane permeabilization. Therefore, tPMP-1 appears to directly target the staphylococcal cytoplasmic membrane as a primary event in its mechanism of action. Specifically, tPMP-1 likely leads to staphylococcal death, at least in part by permeabilizing the bacterial membrane in a voltage-dependent manner.
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PMID:The cytoplasmic membrane is a primary target for the staphylocidal action of thrombin-induced platelet microbicidal protein. 935 67

Malignancy is a risk factor for thromboembolism and anti-cancer chemotherapy can increase this risk. Prophylaxis of thrombosis with very-low-dose warfarin given concurrently with chemotherapy has a significantly reduced rate of thromboembolism in a randomized trial in women with stage IV breast cancer. In a group of 32 patients randomized in one center (16 subjects on warfarin and 16 on placebo), we have prospectively studied the plasma levels of: 1. Markers of 'in vivo' clotting activation (thrombin-antithrombin complex [TAT], prothrombin fragment 1+2 [F1+2] and D-dimer), 2. Factor VII (FVII), and 3. Natural anticoagulants (protein C [PC] and antithrombin [AT]). The aims of this study were: 1. to examine whether laboratory tests predicted those patients who developed thrombosis, and 2. to evaluate the effect of very-low-dose warfarin on hemostatic variables. The patients' hemostatic parameters were evaluated before entry into the study and after starting chemotherapy +/- prophylaxis, before each course for nine courses. Before-treatment results were compared to those of a sex and age-matched non-cancer control group. There was a significant elevation of plasma levels of TAT (p <0.001), F1+2 (p <0.001), D-dimer (p <0.0001) and FVIIa (p <0.05), as well as an increase of FVII proteolysis (p <0.05), whereas plasma PC and AT concentrations were not different from controls. After starting chemotherapy, markers of clotting activation were progressively lower in the group receiving warfarin prophylaxis compared to the group on placebo. Differences between the groups became statistically significant (p <0.01) after the 4th course of chemotherapy. Deep vein thrombosis occurred in two patients in the placebo arm. The results of this study indicate that before therapy, an hypercoagulable state is present in stage IV breast cancer, and after starting chemotherapy, abnormalities of hypercoagulation markers persist, however they are reduced by very-low-dose-warfarin. None of the laboratory variables could predict thrombosis in the single patient.
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PMID:The effect of very-low-dose warfarin on markers of hypercoagulation in metastatic breast cancer: results from a randomized trial. 945 16

Severely burned patients often present a hypercoagulability situation. However, its magnitude, time course, and relationship with organ failure and outcome remains to be established. Forty-three patients were studied on the first and seventh day after burn for hypercoagulability and fibrinolysis parameters. A hypercoagulability and hyperfibrinolysis state was found the first day after burn demonstrated by high levels of activated factor VII (VIIa, p<0.01), thrombin-antithrombin III complex (TAT, p<0.01), tissue plasminogen activator (t-PA, p<0.001) and D dimer (DD, p<0.01) and low levels of antithrombin III (ATIII, p<0.01), protein C (PC, p<0.01), plasminogen (PG, p<0.001) and alpha2 antiplasmin (AP, p<0.001). A paradoxical coexisting hypofibrinolysis was found as suggested by a low global fibrinolytic activity in the euglobulin plasma fraction fibrin plate assay (FA, p<0.01) and high levels of tissue plasminogen activator inhibitor type 1 (PAI-1, p<0.01). On day 7, a less marked hypercoagulability situation was found, with low ATIII (p<0.01) and PC (p<0.01), persisting the hypofibrinolytic situation observed on the first day. Non-survivors (NS) showed higher levels of VIIa (p<0.01), TAT (p<0.05) and t-PA (p<0.05), and lower levels of ATIII (p<0.05), PC (p<0.05) and AP (p<0.001) than survivors (S) on the first day. Also, there was a positive correlation of Marshall organ failure score with ATIII, (r2=0.49, p<0.001), PC, (r2=0.14, p<0.045) and PG levels, (r2=0.41, p<0.0003). Severely burned patients show a state of transient disseminated intravascular coagulation, related to the development of organ failure and outcome.
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PMID:Degree of hypercoagulability and hyperfibrinolysis is related to organ failure and prognosis after burn trauma. 963 Mar 8

Among 379 patients with AML with FAB type M1, 2 and M4-7 diagnosed between 1978 and 1997 in our institution, 19 (5%) had hypofibrinogenemia (HF), ie a fibrinogen level <180 mg/dl. Compared to patients with normal fibrinogen (n = 360) patients with HF had significantly elevated markers of activation of coagulation (TAT, F1.2, FPA) and fibrinolysis (D-dimer, FDP) indicating that disseminated intravascular coagulation/hyperfibrinolysis was the cause of hypofibrinogenemia. Patients with HF had significantly longer prothrombin times, thrombin clotting and reptilase times. Factor X and VIII were significantly lower than in patients without HF. With the exception of M7, HF occurred in all FAB subtypes, but was most common in M5 (12.1%). Patients with HF did not differ from those with normal fibrinogen with regard to age, sex, leukocyte count and other hematological parameters. During induction chemotherapy fibrinogen normalized rapidly (median 5 days) and there was no increased incidence of early hemorrhagic death. The overall and disease-free survival was similar to that of patients without HF.
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PMID:Hypofibrinogenemia in non-M3 acute myeloid leukemia. Incidence, clinical and laboratory characteristics and prognosis. 969 71

A combined hemostatic defect consisting of a reduction in certain procoagulants, anticoagulants (antithrombin III-ATIII-, protein C-PC-) and components of the fibrinolytic system (plasminogen-Plg-) was demonstrated in very-low-birth-weight infants (VLBW <1,500 g) with gestational age 26-32 weeks. Sixteen of them were healthy, 28 were suffering from RDS and 24 from septicemia. The hemostatic defect was more profound in the RDS group, nevertheless increased TAT (thrombin + ATIII complex) and/or PAP values (plasmin + a2-antiplasmin complex) was a more frequent finding in the septicemic group of infants (91.8 vs. 17.9%). Moderate-to-severe thrombocytopenia was detected in a higher percentage in the septicemic (70.8%) than in the RDS group (50%), and increased D-dimers were demonstrated in 34.8 and 28.6% of the infants, respectively. Elevated TAT or PAP values were not always associated with gross coagulation abnormalities, and advanced disseminated intravascular coagulation (DIC) was only documented in 16.7% of the septicemic and 7.1% of the RDS infants. None of the VLBW neonates presented with clinical evidence of thrombosis, although hemorrhagic manifestations were apparent in 34.8 and 14.3% of the neonates with septicemia or RDS, respectively, mainly due to DIC or severe thrombocytopenia. In conclusion, increased TAT and/or PAP values are good indicators of the in vivo activation of the hemostatic system, but still their impact on sick neonates morbidity and mortality remains unknown.
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PMID:Indications of coagulation and/or fibrinolytic system activation in healthy and sick very-low-birth-weight neonates. 974 62

More dialysis treatments have been performed with cellulose based membranes than with any other material. As unmodified cellulose membranes activate the complement system, much effort has been directed toward the development of noncomplement activating cellulose membranes. One successful approach was the substitution of -OH groups in the cellobiose units of the cellulose molecule with tertiary amino groups, which resulted in a membrane called Hemophan. Synthetically modified cellulose (SMC) is a new hemodialysis membrane made by specific chemical modification whereby aromatic benzyl groups are covalently introduced into the cellulosic structure by ether bonds, creating hydrophobic domains within the overall hydrophilic cellulose surface: basic research investigations have shown that a characteristic hydrophobic-hydrophilic balance of surfaces is a prerequisite for improved hemocompatibility. Several cellulose modifications with aliphatic and aromatic groups were performed to achieve a membrane with the desired hemocompatibility profile; SMC, having hydrophobic benzyl groups, causes minimal activation of blood complement, coagulation, and cell activation systems. In vitro experiments with blood showed that C5a generation for SMC was reduced by 94% relative to Cuprophan (compared with 96% for polysulphone, a synthetic hemodialysis membrane). Activation of coagulation (formation of the thrombin-antithrombin III complex [TAT]) in a clinical study showed that SMC caused 16 ng/ml TAT generation compared with 36 ng/ml for polysulphone. SMC, a low-flux cellulosic dialysis membrane, thus combines the typically high diffusive performance characteristics of cellulosic membranes with excellent hemocompatibility, matching synthetic dialysis membranes.
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PMID:Synthetically modified cellulose (SMC): a cellulosic hemodialysis membrane with minimized complement activation. 980 99

The authors studied whether haemostatic abnormalities connected with the development of cerebral circulatory disturbances can be demonstrated in young stroke patients in whom Doppler and angiographic examination failed to reveal deviations indicative of stroke. They determined the in vivo activation of the coagulation system (TAT, F 1 + 2), the degree of secondary fibrinolysis (D-dimer), the plasma levels of the markers of fibrinolysis, with special regard to inhibitors: plasminogen activator inhibitor (PAI-1), alpha 2 antiplasmin (alpha 2 AP), alpha 2 macroglobulin (alpha 2 M), the frequency of pathologic serum lipoprotein (a)-Lp(a)-values and the association of PAI-1 and Lp(a) with the fibrinolytic system. They conclude that in the acute phase of the disease, the TAT and F 1 + 2 values were significantly elevated compared to the control, without change in the D-dimer value. The results suggest that in the tested period increased thrombin generation dominated and it significantly surpassed plasmin activity since the D-dimer values of that period did not indicate substantial increase in secondary fibrinolysis. The results of the study were separately analyzed in acute, chronic TIA and stroke groups. In the TIA and acute group the F 1 + 2 values, while in stroke the TAT values were more elevated. The in vitro fibrinolytic capacity of the patients significantly decreased compared to controls, showing significant correlation with the Lp(a) level, but not with the PAI value. Examination of the marker molecules renders possible to assess the degree of hypercoaguability and of endogenous lysis. Their knowledge is held important for judging the progression of the disease and the therapeutic consequences.
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PMID:[Hemostatic abnormalities in ischemic stroke]. 981 Jan 64

Deep vein thrombosis (DVT) seems to be related to a hypercoagulation and definite hemorheological alterations, but the importance of these alterations in the development of thrombotic events in the deep vein system has not been established. The present study examines both aspects in a group of 55 patients with DVT; the presence of a hypercoagulable state was assessed by quantifying the prothrombin fragment 1+2 (F1+2) and the thrombin-antithrombin III complex (T-AT), and the main hemorheological parameters were evaluated in the acute state and 6 and 12 months later. The results show marked hemorheological, F1+2, and TAT alterations in the acute phase. After 12 months the pattern shows a modest improvement, but erythrocyte aggregation, fibrinogen, F1+2 and T-AT remain increased with respect to the control group (8.51 +/- 1.43; 331 +/- 81 mg/dl; 1.33 +/- 0.60 nmol/l; 3.54 +/- 1.71 ng/ml vs. 8.10 +/- 1.40; 230 +/- 38; 0.94 +/- 0.40; 1.56 +/- 0.59, respectively). These data suggest that the thrombotic event could be influenced by the previous rheological situation and hypercoagulable state.
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PMID:Hemorheological alterations and hypercoagulable state in deep vein thrombosis. 997 63

In this study, we evaluated the role of proteolytic enzymes belonging to the coagulation, fibrinolytic, and plasma contact systems in the early postoperative phase after orthotopic liver transplantation (OLT). Twenty-nine patients were studied at the time of OLT and during the first 2 postoperative weeks. Blood samples were collected daily after OLT and analyzed for kallikrein-like activity (KK), functional kallikrein inhibition (KKI), plasmin-like activity (PL), and alpha2-antiplasmin (AP). In addition, prekallikrein (PKK), prothrombin (PTH), antithrombin III (AT III), plasminogen (PLG), prothrombin/antithrombin III complexes (TAT), prothrombin fragment 1 + 2 (F1 + 2), and plasmin/alpha2-antiplasmin complexes (PAP) were measured. Nineteen patients experienced biopsy-verified acute rejections (AR) and ten patients had uneventful courses and served as controls. Plasma analyses showed that the contact, coagulation, and fibrinolytic systems were activated during OLT. Following OLT, continuous thrombin and plasmin generation was observed, and these effects were more pronounced in the group having an uneventful course than in patients with AR. Factors that could possibly affect plasma proteolytic activity, such as blood product usage during and after OLT and cold ischemia time of the liver graft, did not differ between the groups, nor did the routine liver function tests, alanine aminotransferase (ALT) and aspartate aminotransferase (AST).
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PMID:Plasma proteolytic activity in liver transplant rejection. 1036 91

To reduce the thrombogenic properties of coronary artery stents, a biodegradable polylactic acid (PLA) stent coating with an incorporated thrombin inhibitor and a platelet aggregation inhibitor has been developed. In an ex vivo human stasis model, its effect on platelets, plasmatic coagulation and its release characteristics were studied using whole blood. Bare steel and bare gold-surface stents were compared to steel and gold-surface stents coated with PLA (30 kDa) containing 5% polyethyleneglycol (PEG)-hirudin and 1% iloprost, with an empty tube as control. Markers of activated coagulation (prothrombin fragment F1-2 and thrombin-antithrombin III complex, TAT), were assayed and the release of drugs from the coating was assessed by aPTT and collagen-induced platelet aggregation. Bare steel and gold stents were completely covered by a blood clot, and high levels of coagulation markers (F1-2 fragment and TAT) were detected. No differences in the thrombogenic properties were found between bare gold or steel stents. Coated stents were free of blood clots and only minor elevations of markers were detected. Release data from in-vitro studies over 90 days showed a gradual release of the drugs with an initial exponential release characteristic for PEG-hirudin, slow release of iloprost and a 10% degradation of the PLA carrier. This drug releasing biodegradable coating effectively reduced thrombus formation independent of the metallic surface.
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PMID:Antithrombogenic coating of stents using a biodegradable drug delivery technology. 1045 54


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