Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.5 (thrombin)
 33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The administration of menaquinone-4 (MK-4), one of subclasses of vitamin K2, significantly reduces bone loss in postmenopausal osteoporotic women. However, concerns have been raised about whether vitamin K administration alters the hemostatic balance by inducing a thrombotic tendency. We investigated were whether the administration of vitamin K in the form of MK-4 induced a thrombotic tendency in 29 elderly patients with osteoporosis (5 men, 24 women; age range 78.7+/-5.1 years). Patients were administered 45 mg/day (three times a day, 30 min after each meal) of MK-4 for 12 weeks. Blood samples were obtained from the patients at 0, 4 and 12 weeks after the start of MK-4 administration. A number of hemostatic parameters remained stable under the markedly increased plasma levels of MK-4. However, in patients with suspected vitamin K deficiency, whose plasma levels of vitamin K or factor VII were low, vitamin-K-dependent clotting factors such as factor VII and prothrombin were gradually increased after administration of MK-4. No changes in the sensitive molecular markers such as TAT and F1+2, which reflect the amount of thrombin generated in the blood stream, were observed, even in those patients with suspected vitamin K deficiency. These results indicate that MK-4 can be administered safely, with regard to maintaining the hemostatic balance, to osteoporotic patients receiving no anticoagulant therapy.
 ...
PMID:Vitamin K administration to elderly patients with osteoporosis induces no hemostatic activation, even in those with suspected vitamin K deficiency. 1184 34

Antiphospholipid antibodies (aPL) are associated with an increased risk of thrombosis and recurrent miscarriage. We assessed levels of coagulation activation markers and aPL during normal pregnancy and in women with the antiphospholipid syndrome (aPS). Fluctuations in aPL levels were observed in all patients with aPS. No particular pattern of antibody positivity, or fluctuation in aPL level, was associated with poor pregnancy outcome. A significant increase was observed in levels of factor Xlla (FXIIa; P < 0.001), factor VIIa (FVIIa, P < 0.001), thrombin antithrombin complexes (TAT; P < 0.001), prothrombin fragment F1.2 (F1.2; P < 0.001) and D-dimer (DD; P < 0.05) during normal pregnancy. Factor VIIa, TAT, F1.2 and DD increased significantly before 20 weeks gestation, while a statistically significant increase in FXIIa levels was first detected between weeks 20 and 30 of gestation. In pregnant women with aPS, increases in FXIIa were similar to those in normal pregnancy, but increased FVIIa levels were not observed until after 30 weeks gestation. Similar to normal pregnancy, increased levels of TAT and F1.2 were detected in aPS pregnancies before 20 weeks gestation, but increased DD were not observed until after week 20. Surprisingly, women with aPS receiving low molecular weight heparin prophylaxis had significantly higher (P = 0.02) levels of TAT (median 8.6; interquartile range (IQR) 6.5-20.8) between weeks 20 and 30 of gestation compared to the normal pregnant population (median 5.9; IQR 4.7-7.9), thus indicating increased thrombin generation in women with aPS in mid-pregnancy.
 ...
PMID:Fluctuations in levels of antiphospholipid antibodies and increased coagulation activation markers in normal and heparin-treated antiphospholipid syndrome pregnancies. 1189 13

For rehabilitation training it is recommended that the intensity of exercise should be distinctly below the individual anaerobic threshold (IAT). We investigated platelet activity, reactivity and platelet-leukocyte conjugate formation following a stardardized treadmill (TR) ergometer test at 90% IAT for 60-120 min. Seventeen healthy male non-smokers underwent TR. Blood samples were taken after a 30-min rest, immediately after exercise, and 2 h after exercise completion. Platelets were detected flow cytometrically by CD41 in whole blood, activated platelets by CD62P. In addition, stimulation of platelets in vitro with 7.5 microM TRAP-6 was performed. For testing platelet-leukocyte conjugates, antibodies against CD45 and CD41 were used. After TR the percent of non-stimulated CD62P-positive platelets (%PC) remained unchanged (1.65 +/- 0.56 to 1.73 +/- 0.79%PC) (mean +/- SD). In contrast, an increase (P<0.05) from 31.9 +/- 13.5 to 37.4 +/- 15.0 %PC in CD62P, TRAP-6 stimulated and enhanced (P<0.01) platelet-leukocyte conjugates (11.7 +/- 3.7 to 16.1 +/- 6.9, CD41-%PC) after TR were observed. Both changes were independent of thrombin generation measured by F1+2 and TAT, and reversible after 2 h. Long-term exercise (90% IAT) on a treadmill ergometer only leads to a moderate increase of platelet reactivity and platelet-leukocyte conjugates. The determination of platelet-leukocyte conjugates may offer the possibility to detect an early activation stage of platelets in vivo.
 ...
PMID:Platelet activity, sensitivity to agonist, and platelet--leukocyte conjugate formation after long-term exercise. 1218 12

In the Netherlands, physicians at De Wever Hospital in Heerlen compared seminal plasma samples of 80 men before vasectomy with those of 87 men after vasectomy to determine whether coagulation and fibrinolysis markers appear in seminal plasma and, if so, whether vasectomy has an effect on these parameters. They used blood plasma samples from 80 age-matched healthy men to obtain reference values. Even though the median thrombin-antithrombin III complex (TAT-III) values were greater after vasectomy (4.6 vs. 3 mcg/l), they were not significantly different. Yet, they were significantly higher than the median value in blood plasma (4.6 vs. 2.4 mcg/1; p 0.01). The median prothrombin fragment 1.2 levels were essentially the same before and after vasectomy (0.42 vs. 0.55 nmol/l) and within the same range as those in blood plasma (0.66 nmol/l). Postvasectomy median D-dimer levels were much lower than prevasectomy levels (102 vs. 140 mcg/l; p 0.025) and blood plasma levels (199 mcg/l; p 0.001). The median D-dimer/TAT-III ratio was much lower after vasectomy (20 vs. 33.3; p 0.04) and both pre- and postvasectomy ratios were much lower than that of blood plasma (33.3 vs. 70; p 0.001 and 20 vs. 70; p 0.0001, respectively). Pre- and postvasectomy tissue plasminogen activator activities (t-PAact) were essentially the same (211 vs. 186 x 1000 IU/1). Yet, they were much greater than the median t-PAact in blood plasma (by 1.5 x 1000 IU/1; p 0.0001). These findings show that hemostasis products exist in seminal plasma and that vasectomy changes their concentrations. The researchers called for further research to learn the significance of these markers in seminal plasma. Further studies should consider the presence of hemostasis markers to explain earlier identified vasectomy effects.
 ...
PMID:Fibrinolysis and coagulation markers in seminal plasma before and after vasectomy. 1234 9

Exhaustive exercise leads to an activation of blood coagulation, but the implications of this activation are still unclear. The aim of this study was to investigate if a hypercoagulant stage exists after exhaustive treadmill- or cycle exercise; intrinsic and extrinsic endogenous thrombin potential (ETP) were measured by using the method of Hemker et al. Thirteen healthy male subjects underwent an exhaustive treadmill (TR) or cycle (CY) ergometer test and a control-day in random order. Blood samples were taken, repeatedly, after a 30 min rest, immediately before and after, and 1 h after exercise for measuring intrinsic and extrinsic total thrombin potential (TTPin, TTPex) (including free and alpha 2 -macroglobulin-bound thrombin) and endogenous thrombin potential (ETPin, ETPex), aPTT, PT, F1 + 2 and TAT. In comparison to the pre-value taken immediately before the exercise, the intrinsic TTP was significantly (p < 0.05) increased directly after exercise (TR-TTPin, + 11.6 %; CY-TTPin, + 11.5 %). In contrast, ETPin remained unchanged after both exercises. Additionally for TTPex and ETPex, no changes after exercise were detectable. aPTT was significantly (p < 0.05) shorter after exercise (TR-aPTT, - 16.2 %; CY-aPTT - 17.5 %), F1 + 2-concentrations were higher (p < 0.05) (TR-F1 + 2, + 21.2 %; CY-F1 + 2, + 9.8 %), but TAT remained unchanged. Differences between TR or CY could not be determined. These results show the expected shortening of aPTT and the increase of F1 + 2 indicating an activation of the coagulation system during exercise. However, the unchanged intrinsic and extrinsic ETP lead to the conclusion that in healthy young male subjects the potential for thrombin generation is insignificant, is directly counterbalanced by alpha 2-macroglobulin and is independent of the type of exhaustive exercise done.
 ...
PMID:Thrombin potential and thrombin generation after exhaustive exercise. 1240 82

A 27-year-old woman was admitted to our hospital because of headache, fever and right neck pain. Neurological examination revealed mild meningeal signs, and hyper-reflexia in all extremities. In the laboratory tests, white-cell count was 13,000/mm3, rheumatoid factor(RF) and C-reactive protein(CRP) were positive. The cerebro-spinal fluid showed pleocytosis (56/mm3, neutorophils and lymphocytes were 26 and 28, respectively). Thus, she was diagnosed as aseptic meningitis. A few days later, she had weakness and dysesthesia of the right face and the left extremities. Pulse therapy with intravenous methylprednisolone was started. A magnetic resonance imaging (MRI) of the brain showed a hemorrhagic infarction in the right parietal lobe. In hemostatic markers, thrombin-antithrombin III complex(TAT; 106 ng/dl), D-dimer 1234 ng/dl, prothrombin fragment 1 + 2(F1 + 2; 2.36 nmol/L), beta-thromboglobulin (beta TG; 4,300 ng/dl) and platelet factor 4 (PF-4; 1,770 ng/dl) were extremely elevated. On duplex ultrasonography, a low echo lucent plaque was observed at the right internal carotid artery and the mean blood flow velocity in the right carotid artery was decreased. She was placed on oral prednisolone and warfarin for suspected stroke due to hypercoagulability associated with vasculitis. Afterwards, she discharged from our hospital. Two months later, she was readmitted to our hospital because of irregular menses and vaginal bleeding. Endometrial uterus biopsy was conducted, which revealed a grade I endometrioid adenocarcinoma. She was under total uterectomy without tumor recurrence. After the radical operation, white-cell count, RF, CRP, TAT, D-dimer, F1 + 2, and beta TG were normalized, and the mean flow velocity of the right common carotid artery was increased. Thereafter, she did not experience stroke recurrence. Therefore, we speculated that she had stroke due to hypercoagulability in association with malignancy, that is Trousseau's syndrome. We also assumed that aseptic meningitis, brainstem encephalitis associated with vasculitis in this patient are other clinical variants of paraneoplastic syndrome through immunological mechanisms associated with malignancy. We emphasize that patients with Trousseau's syndrome can be associated with other paraneoplastic manifestations such as vasculitis as seen in this patient.
 ...
PMID:[A young patient with endometrioid adenocarcinoma who suffered Trousseau's syndrome associated with vasculitis]. 1247 93

Epidemiologic studies have shown that exposure to particulate air pollution is associated with short-term increases in cardiovascular morbidity and mortality. These adverse effects of inhaled particulate matter (PM*) may be the indirect result of a PM-induced increase in blood coagulability. This explanation is biologically plausible because prospective studies have shown that increases in blood coagulation parameters are significantly associated with risk of adverse cardiovascular events. We examined the hypothesis that acute exposure to elevated levels of PM causes prothrombotic changes in blood coagulation parameters. Rats with indwelling jugular vein catheters were exposed for 6 hours to filtered air or concentrated ambient PM in New York City air (n = 9 per group per experiment). PM less than 2.5 microm in mass median aerodynamic diameter (PM2.5) was concentrated for animal exposures using a centrifugal concentrator. Blood samples were taken at four time points: before and immediately after exposure and at 12 and 24 hours after the start of exposure. At each time point, six coagulation parameters (platelet count, fibrinogen level, factor VII activity, thrombin-antithrombin complex [TAT] level, tissue plasminogen activator [tPA] activity, and plasminogen activator inhibitor [PAI] activity) were measured as well as all standard blood count parameters. Five concentrated-PM exposure experiments were performed over a period of 8 weeks in the summer of 1999. PM exposure concentrations ranged from 95 to 341 microg/m3. Statistical significance was determined by two-way analysis of variance (ANOVA) on the postexposure data with time and exposure status as main effects. There were no consistent exposure-related effects on any of the end points across the five experiments and no indication of any dose-dependent effects. Most of the statistically significant differences that were observed do not represent adverse effects. Therefore, the results of this study do not indicate that exposure to concentrated ambient PM causes adverse effects on blood coagulation in healthy rats.
 ...
PMID:Effect of concentrated ambient particulate matter on blood coagulation parameters in rats. 1250 39

Possible correlation of the effects of pharmacotherapy on the inhibition of the in-vivo generation of thrombin and on the prevention of thrombus extension in patients with deep vein thrombosis (DVT) could help to define patients at higher risk. Patients with symptomatic deep vein thrombosis confirmed by phlebography were randomised to intravenous unfractionated heparin (UFH), or a subcutaneous low-molecular-weight heparin (reviparin) twice daily for one week, or a subcutaneous reviparin once daily for four weeks. The patients were treated with oral anticoagulants for at least 3 months. Main endpoints were regression of thrombus on phlebography on Day 21 and recurrent symptomatic venous thromboembolism up to 3 months. Coagulation parameters, markers of in-vivo thrombin generation, and TFPI-release were determined at randomisation, weeks 1 and 3. Four hundred sixty six responders (reduction of at least 30 per cent in Marder score) and 419 non-responders (Marder score unchanged or changed less than +/-30%) showed no significantly different baseline characteristics. The non-responder group had a higher median Marder score at baseline and after one and three weeks of treatment, and had significantly higher fibrinogen levels, TAT complexes and F1+2 values than responders. There were no significant differences in coagulation parameters between non-responders and patients with asymptomatic + symptomatic VTE with the exception of higher TAT complexes at baseline. Significant differences in Marder score and coagulation parameters at baseline were found between responders and nonresponders. Non-responders have a higher risk tosuffer recurrent VTE and may need intensified treatment.
 ...
PMID:Risk factors and coagulation parameters in relationship to phlebographic response and clinical outcome in the treatment of acute deep vein thrombosis. 1257 6

Heparin has been conventionally used as an anticoagulant for medical and surgical indications. Because factor Xa is an essential component of the prothrombinase complex and leads to the generation of thrombin, its inhibition has become a focus of newer antithrombotic drug development. The in vitro anticoagulant profile of DX-9065a, a synthetic direct factor Xa inhibitor, was studied using activated clotting time assay, thrombelastography, and global clotting tests, such as prothrombin time (PT), activated partial thromboplastin time (aPTT), diluted aPTT, Heptest, Heptest-HI, dilute Russell's viper venom time (dRVVT), thrombin time, ecarin clotting time, and amidolytic anti-Xa assay. In addition, the effect of DX-9065a on platelet aggregation and inhibition of thrombin generation markers (FPA, F1+2, and TAT) were studied. The pharmacokinetic and pharmacodynamic profiles of DX-9065a were also studied in a non-human primate (Macaca mulatta) model. DX-9065a produced a concentration-dependent increase in the Hemochron celite ACT and HemoTec ACT. Clotting times of 538 +/- 19 and 401 +/- 12, respectively, were reached at a concentration of 25 microg/mL signifying that DX-9065a may be useful in interventional cardiological procedures. DX-9065a prolonged the r-time on thrombelastography. DX-9065a did not show any effect on adenosine diphosphate (ADP)-, collagen-, epinephrine-, and arachidonic acid-induced platelet aggregation at concentrations up to 10 microgram/mL. DX-9065a exhibited a concentration-dependent prolongation of the PT, aPTT, diluted aPTT, Heptest, dRVVT, and reached the clotting times of 51.6, 132, 193, 47.9, 129.9 seconds, respectively, at a final concentration of 12.5 microgram/mL; compared to a control value of 10.6, 30.2, 41.9, 14, 32.2 seconds, respectively. DX-9065a did not affect the ecarin clotting time and thrombin time at concentrations up to 12.5 microgram/mL. Because DX-9065a prolonged the dRVVT, this may impact diagnostic screening of patients with systemic lupus erythematosus.
 ...
PMID:Global anticoagulant effects of a synthetic anti-factor Xa inhibitor (DX-9065a): implications for interventional use. 1264 18

The systemic inflammatory response to cardiopulmonary bypass (CPB) may contribute to the development of postoperative complications. Heparin-coated circuits and poly2methoxyethylacrylate (PMEA)-coated circuits have been developed to reduce the risk of such complications. We compared the biocompatibility of these circuits. Twelve patients scheduled to undergo elective coronary artery bypass grafting (CABG) with CPB were assigned to CPB with a PMEA-coated circuit (PMEA-coated group, n=6) or a heparin-coated circuit (heparin-coated group, n=6). The plasma concentrations of the following inflammatory markers were measured before CPB and just after, 4 hours after, and 24 hours after the termination of CPB: cytokines (interleukin [IL]-6, IL-8, IL-10), complement factor (C3a), polymorphonuclear elastase (PMNE), and coagulofibrinolytic factors (thrombin-antithrombin III complex [TAT], D-dimer). Postoperative clinical response was evaluated on the basis of respiratory index, blood loss, and the postoperative and preoperative body-weight percent ratio. There were no significant differences between the groups in the plasma concentrations of IL-6, IL-10, C3a, PMNE, TAT, or D-dimer. Plasma IL-8 concentrations were below the assay detection limits at all time points in both groups. Clinical variables did not differ significantly between the groups. In conclusion, PMEA-coated CPB circuits are as biocompatible as heparin-coated CPB circuits and prevent postoperative organ dysfunction in patients undergoing elective CABG with CPB.
 ...
PMID:Biocompatibility of poly2methoxyethylacrylate coating for cardiopulmonary bypass. 1266 26


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>