<ORIGINAL ARTICLE>Characterization of a new coagulant enzyme isolated from Trimeresurus okinavensis (Himehabu snake) venom

A potent, proteinaceous inducer of coagulation factors, has been purified to homogeneity from Trimeresurus okinavensis (Himehabu snake) by ion exchange chromatography and molecular sieving. It has an apparent molecular weight of 28,000 and it specifically converts fibrinogen to fibrin through an enzymatic reaction. This activity was confirmed by a method using synthetic substrate S-2238, though the fraction from a DEAE sephacel column chromatography shows amidolytic activity of S-2251 and S-2366, which are commonly used to measure plasmin and activated protein C activity, respectively, as well as S-2238. This thrombin-like activity of the final product was not affect by the addition of heparin and AT-III. This enzyme also aggregates normal platelets. It is considered that this purified enzyme would be useful as a hemostatic agent or research reagent

Octreotide-Treated Diabetes Accompanied by Endogenous Hyperinsulinemic Hypoglycemia and Protein-Losing Gastroenteropathy

Occurrence of hypoglycemia in diabetes patients is very rare. We report here a case of frequent hypoglycemic attacks caused by inappropriate endogenous hyperinsulinemia in a female patient with poorly controlled diabetes and protein-losing gastroenteropathy. The blood glucose profiles of the patient were unstable. Results of the fasting test performed to investigate the cause of hypoglycemia suggested endogenous hyperinsulinism. Repeated selective arterial calcium injection tests suggested that hyperinsulinemia might be extrapancreatic in origin. However, efforts to detect a responsible lesion such as insulinoma were unsuccessful. Octreotide was used for the treatment of hypoglycemia and protein-losing gastroenteropathy. After treatment, although her leg edema caused by hypoalbuminemia persisted, hypoglycemia almost disappeared

Significance of fully automated tests for the diagnosis of antiphospholipid syndrome

AbstractAntiphospholipid antibodies (aPLs) can vary both immunologically and functionally, thus it is important to effectively and correctly identify their presence when diagnosing antiphospholipid syndrome. Furthermore, since many immunological/functional tests are necessary to measure aPLs, complete examinations are often not performed in many cases due to significant burden on the testing departments. To address this issue, we measured aPLs defined according to the classification criteria (anticardiolipin antibody: aCL) IgG/IgM and anti-β2 glycoprotein I antibody (aβ2GPI) (IgG/IgM) as well as non-criteria antibodies (aCL IgA, aβ2GPI IgA and aβ2GPI domain I), in a cohort of 211 patients (61 APS, 140 disease controls and 10 healthy individuals). APLs were measured using a fully automated chemiluminescent immunoassay instrument (BIO-FLASH®/ACL AcuStar®) and with conventional ELISA tests. We demonstrated that both sensitivity and accuracy of diagnosis of aCL IgG and aβ2GPI IgG were high, in agreement with the past reports. When multiple aPLs were examined, the accuracy of diagnosis increased. The proportion of APS patients that were positive for 2 or more types of aPLs (47/61, 77%) was higher than that of patients with systemic lupus erythematosus (SLE)(3/37, 9%), those with non-SLE connective tissues diseases (1/53,2%), those with other diseases or healthy volunteers. Based on these findings, it was concluded that the fully automated chemiluminescent immunoassay instrument, which allows the simultaneous evaluation of many types of aPLs, offers clear advantages for a more complete, more rapid and less labor-intensive alternative to running multiple ELISA and could help in better diagnosis for suspected APS patients

Octreotide-Treated Diabetes Accompanied by Endogenous Hyperinsulinemic Hypoglycemia and Protein-Losing Gastroenteropathy

Occurrence of hypoglycemia in diabetes patients is very rare. We report here a case of frequent hypoglycemic attacks caused by inappropriate endogenous hyperinsulinemia in a female patient with poorly controlled diabetes and protein-losing gastroenteropathy. The blood glucose profiles of the patient were unstable. Results of the fasting test performed to investigate the cause of hypoglycemia suggested endogenous hyperinsulinism. Repeated selective arterial calcium injection tests suggested that hyperinsulinemia might be extrapancreatic in origin. However, efforts to detect a responsible lesion such as insulinoma were unsuccessful. Octreotide was used for the treatment of hypoglycemia and protein-losing gastroenteropathy. After treatment, although her leg edema caused by hypoalbuminemia persisted, hypoglycemia almost disappeared

Considerations for simultaneous detection of autoantibodies to coagulation factor and lupus anticoagulant

In patients with autoimmune coagulation factor deficiency (AiCFD), the production of autoantibodies that inhibit coagulation factors in the blood reduces the activity of those relevant coagulation factors, resulting in severe bleeding symptoms. Recently, reports of patients with AiCFD have noted the concomitant detection of lupus anticoagulant (LA), a risk factor for thrombosis. LA-positive patients may show bleeding symptoms due to decreased activity of coagulation factor II (FII) caused by autoantibodies against FII, in addition to thrombotic symptoms, a condition termed LA-hypoprothrombinemia syndrome (LAHPS). Anti-FII antibodies in LAHPS cases are frequently cleared antibodies that can be detected using immunological techniques, such as enzyme-linked immunosorbent assay (ELISA). Recently, several cases of coagulation FV inhibitors, known as autoimmune FV deficiency, have been reported. Some of these cases may be complicated by LA, which can cause thrombosis. False-positive results for anticoagulant inhibitors are known to occur in LA cases; therefore, immunological confirmation of antibodies against coagulation factors is recommended. Additionally, acquired hemophilia A (AHA), caused by autoantibodies against FVIII, is a typical acquired hemorrhagic diathesis, although affected patients may present with thrombosis associated with LA. Thus, it is important to remember that hemorrhagic diathesis due to autoantibodies against clotting factors can also result in thrombosis, as demonstrated by the co-detection of LA. When clotting factor inhibitors are detected in LA-positive individuals, it is important to confirm the presence of autoantibodies against coagulation factors using immunological methods, such as ELISA, to avoid false-positive results

Noble-Collip Drum Trauma Induces Disseminated Intravascular Coagulation But Not Acute Coagulopathy of Trauma-Shock

Background: There are two opposing possibilities for the main pathogenesis of trauma-induced coagulopathy: an acute coagulopathy of trauma shock and disseminated intravascular coagulation with the fibrinolytic phenotype. Objective: The objective of this study was to clarify the main pathogenesis of trauma-induced coagulopathy using a rat model of Noble-Collip drum trauma. Methods: Eighteen rats were divided into the control, trauma 0, and trauma 30 groups. The trauma 0 and 30 groups were exposed to Noble-Collip drum trauma. Blood samples were drawn without, immediately after, and 30 min after Noble-Collip drum trauma in the control, trauma 0, and trauma 30 groups, respectively. Coagulation and fibrinolysis markers were measured. Thrombin generation was assessed according to a calibrated automated thrombogram. Results: Spontaneous thrombin bursts resulting from circulating procoagulants were observed in the nonstimulated thrombin generation assay immediately after trauma. Soluble fibrin levels (a marker of thrombin generation in the systemic circulation) were 50-fold greater in the trauma groups than in the control group. The resultant coagulation activation consumed platelets, coagulation factors, and antithrombin. Endogenous thrombin potential and factor II ratio were significantly negatively correlated with antithrombin levels, suggesting insufficient control of thrombin generation by antithrombin. High levels of active tissue-type plasminogen activator induced hyperfibrin(ogen)olysis. Soluble thrombomodulin increased significantly. However, activated protein C levels did not change. Conclusions: The systemic thrombin generation accelerated by insufficient antithrombin control leads to the consumption of platelets and coagulation factors associated with hyperfibrin(ogen)olysis. These changes are collectively termed disseminated intravascular coagulation with the fibrinolytic phenotype

Increase in plasma thrombin-activatable fibrinolysis inhibitor may not contribute to thrombotic tendency in antiphospholipid syndrome because of inhibitory potential of antiphospholipid antibodies toward TAFI activation

Background: The causes of thrombosis in antiphospholipid syndrome (APS) remain unknown, though several hypotheses in regard to hypofibrinolysis have been proposed. Objective: To clarify the mechanism, we measured plasma levels of thrombin-activatable fibrinolysis inhibitor (TAFI) in APS patients. Methods and Results: Both the TAFI antigen (TAFI:Ag) level measured with an ELISA, and thrombin-thrombomodulin-dependent TAFI activity (TAFI:Ac) were elevated in 68 APS patients as compared with those in 66 healthy controls, though they were lower than those in 46 patients with autoimmune diseases. As for the influence of antiphospholipid antibodies (aPL) on TAFI levels, the mean TAFI:Ac level in 39 SLE patients positive for APS was significantly lower than that in 27 SLE patients without APS, whereas there was no difference in TAFI:Ag between those groups. Furthermore, purified IgG from patients positive for aPL, and monoclonal aPL (EY2C9 and 23-1D) inhibited the activation of TAFI in a concentration dependent manner. Conclusion: These results suggest that aPL inhibits TAFI activation by affecting the function of thrombomodulin-thrombin complex through phospholipids. Although TAFI in plasma is elevated in autoimmune diseases including APS, we concluded that an elevated level is not likely a risk factor for thrombosis in APS patients, because of the inhibition of TAFI activation by aPL

Massive amounts of tissue factor induce fibrinogenolysis without tissue hypoperfusion in rats

Trauma-induced tissue factor (TF) release into the systemic circulation is considered to play an important role in the development of disseminated intravascular coagulation (DIC) immediately after severe trauma. However, the relationship between TF and hyperfibrinolysis, especially fibrinogenolysis, has been unclear. A total of 18 rats were divided into three groups: (a) the control group was infused with normal saline; (b) the low-dose group was infused with 4 U/kg TF; and (c) the high-dose group was infused with 16 U/kg TF. Arterial blood was drawn immediately and 2 and 4 h after the start of TF infusion. At each sampling point, arterial blood gases, platelet counts, and coagulation variables were measured. The fibrinogen degradation products were evaluated by a Western blot analysis. Hypotension, hypoxemia, and lactic acidosis were not observed in any of the three groups. In proportion to the doses of TF, the platelet counts, coagulation, and fibrinolysis variables deteriorated in line with DIC. The alpha 2-plasmin inhibitor levels significantly decreased in the high-dose group compared with the other groups. The amounts of fibrinogen degradation products increased in proportion to the doses of TF. The plasmin-alpha 2-plasmin inhibitor complex level in the high-dose group increased more than that of the other groups. In conclusion, TF can induce DIC associated with fibrinolysis and fibrinogenolysis without tissue hypoperfusion. The decrease in the alpha 2-plasmin inhibitor level and the significant increase in the plasmin level may be the two main factors underlying the pathogenesis of hyperfibrin(ogen)olysis after TF administration