Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.2.2.7 (heparinase)
 1,270 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a previous paper, we demonstrated that deep hypothermia in dogs provokes a release of a heparin-like factor. In the present study, we investigated some properties of this anticoagulant activity and compared it with exogenous heparin activity. The endogenous anticoagulant inhibited factors IIa and Xa; it was hydrolysed by heparinase and was AT III dependent. However, it differed from heparin in so far as it was adsorbed on cation exchange gel at neutral pH, its inhibition was decreased in the presence of neuraminidase, and it could not be neutralized with Polybrene or protamine. A release of heparan sulphate is suggested but remains to be demonstrated.
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PMID:Characterization of a heparin-like activity released in dogs during deep hypothermia. 314 96

Thrombelastography (TEG) correlates with postoperative chest drain output in patients undergoing cardiopulmonary bypass (CPB). In vitro incubation with heparinase allows TEG monitoring during CPB, despite heparin anticoagulation. Hypothermia impairs coagulation, but these effects cannot be assessed by standard coagulation tests performed at 37 degrees C. The aim of this study was to assess the effects of hypothermia on TEG. Therefore, we have compared normothermic and temperature-adapted TEG in 30 patients undergoing CPB. Our data showed significantly impaired reaction time (r), kinetic time (k), and angle alpha (alpha) in temperature-adapted compared with normothermic TEG. Maximum amplitude (MA), reflecting absolute clot strength, was not affected at temperatures of 33-37 degrees C. These findings indicate a decrease in the speed of clot formation, but not absolute deterioration in clot quality. Furthermore, heparinase-modified TEG indicated that there were nine cases in which heparin effects persisted after heparin reversal with protamine, providing a rational guide to protamine therapy.
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PMID:Effects of hypothermia on thrombelastography in patients undergoing cardiopulmonary bypass. 962 30

In cardiopulmonary bypass (CPB), despite heparin regimens in which the activated clotting time (ACT) is kept at more than 400 s, there is biochemical evidence of thrombin generation indicating activation of the coagulation system and increased fibrinolytic activity. Therefore, to reduce the coagulant activation has been one of the main issues in the improvement of CPB. The purpose of this study was to compare the heparin concentration with the ACT and to evaluate the effect of keeping higher heparin concentration on the coagulation and fibrinolytic systems during hypothermic CPB, employing moderate hypothermia (MHT) or deep hypothermic circulatory arrest (DHT). Heparin was either administered to maintain an ACT >400 s (ACT group) or to maintain a whole blood heparin concentration of 3 mg/kg (heparin group). At the lowest core temperature during CPB, the ACT and the heparinase ACT (unrelated to heparin concentration) were increased the most whereas the whole blood heparin concentration was less than half the initial concentration in both ACT groups of MHT and DHT. The thrombin-antithrombin III (TAT) content just after CPB in both MHT and DHT was significantly lower in the heparin group than in the ACT group. In conclusion, ACT does not reflect the whole blood heparin concentration during hypothermic CPB. Furthermore, maintenance of the higher heparin concentration during hypothermic CPB may suppress the activation of the coagulation system via thrombin inhibition. That effect was more remarkable in deep hypothermic CPB. Therefore, we believe that anticoagulation management during hypothermic CPB should be based on the maintenance of the higher blood heparin concentration.
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PMID:Maintenance of blood heparin concentration rather than activated clotting time better preserves the coagulation system in hypothermic cardiopulmonary bypass. 1067 57

Platelet dysfunction and loss of procoagulants and platelets leads to impaired hemostasis after cardiopulmonary bypass (CPB). Preoperative platelet sequestration delays surgery, and the large volume shifts, necessary to harvest therapeutically effective components, may be associated with hemodynamic instability. We performed platelet and plasma sequestration after the initiation of CPB during the cooling period in patients undergoing surgery in deep hypothermic cardiac arrest. Five patients who underwent major vascular surgery in deep hypothermia were enrolled in this pilot study. Platelet and plasma sequestration was performed during cooling with the CATS cell saver using the plasma sequestration set. Before processing, 2 x 1,000 ml of blood were concentrated by means of hemofiltration to reduce dilution effects of CPB. The autologous platelet concentrates were rotated at 24 degrees C, and the plasma was stored at room temperature. The harvested plasma and platelets were re-transfused during modified ultrafiltration after CPB. Platelet count, 20 mmol/L ADP stimulated platelet aggregation, and fibrinogen levels were measured preoperatively in the harvested material and in patient blood before and after transfusion. A heparinase thromboelastogram (TEG) was performed preoperatively before and after re-transfusion. There was a significant increase in the ADP stimulated platelet aggregation, platelet count, fibrinogen level, and maximum amplitude of the TEG after re-transfusion of the harvested material. No patient needed transfusion of fresh frozen plasma or random donor platelet concentrates. No patient needed re-exploration due to hemorrhage. The data presented provide evidence that autologous plasma and platelet sequestration during CPB initiation is effective. The harvested material reveals a high platelet count and fibrinogen level and preserves functional integrity.
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PMID:Autologous plasma and platelet sequestration at the beginning of cardiopulmonary bypass: a pilot investigation in five patients undergoing extended vascular surgery in deep hypothermia. 1181 86