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)

To evaluate whether all-trans-retinoic acid (ATRA) is able to modulate the hemostatic system in patients with solid tumors, we studied patients with locally advanced breast cancer who were enrolled in a Phase Ib study of ATRA +/- Tamoxifen (Tam). In this study, two groups of 15 patients/each were treated for 21 days before operation with ATRA at three doses (15, 45, or 75 mg/m(2)/day on alternate days) given alone (group 1) or in combination with Tam (group 2). One additional group received Tam alone. Plasma samples were evaluated for hypercoagulation markers (FVIIa, F1+2, TAT, D-dimer), fibrinolysis proteins (t-PA, PAI-1), and coagulation inhibitors (protein C, AT). At baseline, cancer patients had FVIIa, F1+2, TAT, and PAI-1 significantly greater than control subjects. During treatment, in the patients given ATRA alone, hypercoagulation markers appeared unmodified. Instead, subjects given Tam alone had a significant elevation of FVIIa, F1+2, and TAT versus baseline. However, in the ATRA + Tam groups, hypercoagulation markers were decreased compared with Tam alone. These results suggest that in selected conditions, pre-operative ATRA may modulate the hypercoagulable state of breast cancer patients.
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PMID:Effect of all-trans-retinoic acid on the hypercoagulable state of patients with breast cancer. 1199 76

In June, 1997, we initiated a prospective study to analyze the effect of granulocyte colony-stimulating factor (G-CSF) on coagulation system in peripheral blood stem cells (PBSC) donors following G-CSF administration. Since, 25 consecutively healthy donors received G-CSF (filgrastim) to mobilize and collect PBSC and 20 donors were finally included in the study. Blood samples were collected immediately before starting G-CSF and prior to PBSC collection to analyze the following parameters: prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, hypercoagulability markers (D-dimer, TAT complex, F1 + 2), natural anticoagulants (antithrombin, protein C, protein S), endothelial activation markers [von Willebrand factor antigen (vWF:Ag) and angiotensin converting enzyme (ACE)], and resistance to activated protein C. We found a significant increase in F1 + 2 and D-dimer while a significant decrease of antithrombin and protein C activity was evidenced. Regarding endothelial cell activation markers, a significant increase of vWF:Ag with a slightly significant decrease of ACE were also observed. Therefore, in PBSC donors receiving G-CSF our results reveal activation of both coagulation and endothelial cells that could favor the developing of thrombotic events. In consequence, a careful monitoring should be considered in those cases with risk factors for thrombosis.
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PMID:Induction of a hypercoagulability state and endothelial cell activation by granulocyte colony-stimulating factor in peripheral blood stem cell donors. 1220 56

The activated protein C (APC) resistance phenotype associated with an abnormal factor V Leiden (FVL), and the G20210A prothrombin gene mutation are the most common findings in patients with venous thromboembolism (VTE). In a group of 210 patients, we compared the levels of markers of coagulation activation in carriers of FVL (71 heterozygous, 30 homozygous), G20210A prothrombin mutation (88 heterozygous) or both mutations combined (21 heterozygous), in order to assess whether these markers allow identification of a group of patients with a higher risk of thrombosis; they were also compared to normal values. A total of 143 patients had a personal history of VTE and 67 were asymptomatic. None of them had other hereditary causes of thrombophilia or an antiphospholipid syndrome. None were currently treated with either anticoagulant or hormonal treatment. Pregnant women were excluded. No significant difference between the four groups of patients could be found in the levels of F1+2, TAT and DDI. Levels were all significantly higher than the control values (p<0.05). The levels of F1+2 and TAT were similar in patients with or without a history of VTE, regardless of the type of mutation. DDI levels were significantly higher in patients with a history of VTE than in asymptomatic subjects (443+/-248 vs. 333+/-222 ng/ml, p=0.02) but with only 57% sensitivity and specificity. In conclusion, our study confirms the hypercoagulable state found in mutation carriers and points out the inability of F1+2 and TAT assays to identify a group of subjects at higher risk of thrombosis, within carriers of genetic risk factors. Although the sensitivity and specificity of DDI assay are low, high DDI concentrations tend to be associated with the risk of VTE.
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PMID:Markers of activated coagulation in patients with factor V Leiden and/or G20210A prothrombin gene mutation. 1241 82

The protein C pathway serves as a modulating system with both anti-inflammatory and anticoagulant properties and is intimately involved in the pathophysiology of inflammation and sepsis. Treatment with recombinant human activated protein C (rhAPC) can reduce the mortality of severe sepsis. We investigated whether an elevation of plasma protein C levels to supra-normal levels by infusion of a protein C zymogen concentrate has an effect on coagulation, protein C activation or inflammation in a human endotoxemia model. Eleven healthy male volunteers were enrolled in a double-blind, placebo-controlled two-way cross-over trial. Ten minutes after infusion of 2ng/kg endotoxin each volunteer received either placebo or a plasma-derived protein C zymogen concentrate (Ceprotin, Baxter) (150 U/kg as a slow bolus infusion followed by 30 U/kg/h continuous infusion until 4 hours after LPS-infusion). Protein C antigen and activity increased 4- to 5-fold after infusion of the concentrate. APC was generated during endotoxin-induced inflammation in the placebo (1.6 fold increase) and the protein C period (4.0-fold increase). The increase of APC levels correlated with the TNF-alpha and IL-6 release in both periods (r = 0.65-0.68; p < 0.05) and paralleled the protein C antigen and activity levels in the period with supranormal protein C levels. Supra normal protein C levels resulted in slightly, although non-significant, lower tissue factor mRNA expression and thrombin generation (TAT, F1+2). Systemic inflammation (TNF-alpha, IL-6) was not influenced by protein C zymogen concentrate administration. Infusion of protein C zymogen was safe and no adverse effects occurred. The increase of protein C levels several fold above the normal range resulted in a proportional increase of the APC levels, but had no major anticoagulant, anti-inflammatory or profibrinolytic effects. Low grade endotoxemia itself induces significant protein C activation, which correlates with the TNF release.
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PMID:The effects of supra-normal protein C levels on markers of coagulation, fibrinolysis and inflammation in a human model of endotoxemia. 1673 92

There is wide disagreement about the measurement of various hemostatic parameters in patients with chronic renal failure (CRF) concerning treatment with either hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). This study aims to characterize the coagulopathy in patients with CRF both before initiating dialysis, when the patients are expected to have a steady hemostatic state and after starting regular HD or CAPD. The measurements were repeated in a group of patients who received a successful renal transplant to see whether the coagulopathy associated with CRF would be corrected by this lasting therapy. The study, which was mainly cross-sectional and prospective, included two groups: 49 patients with CRF with their age ranging from 17 to 67 years were divided as follows: those on regular HD (n=20), CAPD (n=9) and patients after transplant (n=20). The tests were also done on 34 healthy controls. Significant hyper-fibrinogenemia was recorded in all three study groups. The HD group showed significant elevation in the plasma levels of AT III and total protein S and a significant reduction in free protein S and protein C, when compared with healthy controls. These inhibitors, except total PS, displayed similar fluctuations in the CAPD group. In the transplant patients, there was significant elevation of AT III and total protein S, a reduction in free PS and no significant changes in PC levels. A significant elevation was found in the levels of F1+2, TAT and D-Dimer in HD and in transplant patients, when compared with controls. In CAPD patients, only D-Dimer levels showed a significant increase. The tPA and PAI-1 levels in the three study groups were similar to the control group. Our study revealed significant activation of the hemostatic system, more pronounced in patients on HD than CAPD. This coagulopathy remained only partly corrected following successful kidney transplantation.
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PMID:Successful kidney transplantation does not reverse the coagulopathy in patients with chronic renal failure on either hemo or peritoneal dialysis. 1749 91

Alterations in haemostasis are frequently observed in children with acute lymphoblastic leukemia (ALL). It was the objective of this study to analyse age-related disturbances in coagulation and fibrinolysis parameters during the induction phase of the antileukemic treatment. Sixty-four children were classified by age into three groups (1-5, 6-10, 11-16 years), and studied during induction treatment of ALL including four weeks of dexamethasone, followed by two weeks tapering of dexamethasone during which 6,000 IU/m(2) native L-Asparaginase (total 4 doses) was administered intravenously twice weekly. Blood samples were collected immediately before each L-Asparaginase infusion to analyze procoagulant (fibrinogen, factor [F] II, FV, FVII, F IX, F X) and anticoagulant factors (antithrombin [AT], protein C, protein S), parameters of thrombin generation (F1+2, TAT) and fibrinolysis (alpha2-antiplasmin, plasminogen, PAP, D-dimer). Children were in a hypercoagulable state after four weeks of dexamethasone due to upregulation of coagulation parameters. Upregulation was highest in the two youngest age groups. During L-Asparaginase treatment the 11- to 16-year-olds showed lower values in procoagulant and, even more, in anticoagulant factor levels compared to the younger children. Activation markers of thrombin generation and fibrinolysis did not change over time during the study period. Decreased synthesis of alpha2-antiplasmin and plasminogen during L-Asparaginase treatment resulted in less potential of clot lysis by plasmin in children older than 11 years of age. In conclusion, a more severe decline of anticoagulant and fibrinolytic parameters in children between 11 and 16 years of age underline that these children are at higher risk of thrombosis during ALL induction treatment.
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PMID:L-Asparaginase and the effect of age on coagulation and fibrinolysis in childhood acute lymphoblastic leukemia. 1869 Mar 55

Immunity to the bovine apicomplexan parasite Theileria parva is associated with MHC-I restricted CD8+ T cell responses directed against the intralymphocytic schizont stage of the parasite. A number of schizont-stage antigens that are targets of CD8+ T cell responses from immune animals have been identified but an effective delivery strategy that consistently induces protective CD8+ T cell responses remains to be developed. This study aimed to determine whether fusing Tat, a cell penetrating peptide (CPP) from HIV-1 TAT, to a CD8+ T cell target antigen from T. parva (Tp2) enhances the cytosolic delivery and subsequent stimulation of bovine CD8+ T cell responses in vitro. Using IFN-gamma ELISpot and cytotoxicity assays, it was demonstrated that recombinant Tat-Tp2 fusion protein possessed a superior ability to access MHC-I processing and presentation pathway and to stimulate CD8+ T cell responses compared to recombinant Tp2 protein. Exposure of APC to Tat-Tp2 protein for only 30 min was sufficient for protein uptake and stimulation of CD8+ T cells. This work describes for the first time the utility of a CPP to enhance MHC-I presentation in a veterinary species and supports the evaluation of CPP fusion proteins in the induction of CD8+ T cell responses in vivo.
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PMID:Fusion of a cell penetrating peptide from HIV-1 TAT to the Theileria parva antigen Tp2 enhances the stimulation of bovine CD8+ T cell responses. 1924 7

We have shown that platinum nanoparticle species (nano-Pt) is a superoxide dismutase/catalase mimetic that scavenges superoxide and hydrogen peroxide. In Caenorhabditis elegans, nano-Pt functions as an effective antioxidant that induces an extension in lifespan and strong resistance against excessive oxidative stress. Our study with C. elegans was the first trial to use nano-Pt as a bio-active substance. However, a high concentration of nano-Pt was required for these survival effects, probably due to limited membrane permeability. Here, we show that the conjugation of nano-Pt with an HIV-1 TAT fusion protein C-terminally linked to a peptide with high affinity for platinum improves internalization, eliciting a similar level of antioxidant effects at one hundredth the concentration of unconjugated nano-Pt. This approach is a potential method to facilitate translocation of bio-active nanoparticles into living organisms and could be a model assay for estimate the effects of antioxidant in living organism.
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PMID:The effect of TAT conjugated platinum nanoparticles on lifespan in a nematode Caenorhabditis elegans model. 2043 16

We have adapted the corn-trypsin inhibitor whole-blood model to include EA.hy926 as an endothelium surrogate to evaluate the vascular modulation of blood coagulation initiated by relipidated recombinant tissue factor (rTf) and a cellular Tf surrogate, lipopolysaccharide (LPS)-stimulated THP1 cells (LPS-THP-1). Compared with bare tubes, EA.hy926 with rTf decreased the rate of thrombin formation, ITS accumulation, and the production of fibrinopeptide A. These phenomena occurred with increased rates of factor Va (fVa) inactivation by cleavages at R(506) and R(306). Thus, EA.hy926 provides thrombin-dependent protein C activation and APC fVa inactivation. Comparisons of rTf with LPS-THP-1 showed that the latter gave reduced rates for TAT formation but equivalent fibrinopeptide A, and fV activation/inactivation. In the presence of EA.hy926, the reverse was obtained; with the surrogate endothelium and LPS-THP-1 the rates of TAT generation, fibrinopeptide release, and fV activation were almost doubled, whereas cleavage at R(306) was equivalent. These observations suggest cooperativity between the 2 cell surrogates. These data suggest that the use of these 2 cell lines provides a reproducible quasi-endothelial quasi-inflammatory cytokine-stimulated monocyte system that provides a method to evaluate the variations in blood phenotype against the background of stable inflammatory cell activator and a stable vascular endothelial surrogate.
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PMID:Cellular regulation of blood coagulation: a model for venous stasis. 2086 79


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