To assess the effects of a monoclonal antibody against the human platelet glycoprotein (GP) IIb/IIIa complex in vivo, the murien monoclonal antibody NNKY 1-32 was injected into Japanese monkeys.
All of the IgG, F(ab′)₂ and Fab fragments of NNKY 1-32 completely inhibited monkey platelet aggregation induced by ADP or collagen in vitro.
Four monkeys received 0.4 and 1.0mg/kg of NNKY 1-32 F(ab′)₂ or Fab fragments, while another four received 0.4mg/kg of NNKY 1-32 IgG fragments. In two monkeys given the IgG fragments of the antibody, platelet counts decreased remarkably. And in two other monkeys, transient thrombocytopenia was observed. In all monkeys, bleeding time was prolonged, platelet aggregation was suppressed, and the antibodies were associated with the platelets for up to 72 hours. Compared with the Fab fragments of the antibody, the F(ab′)2 fragments strongly suppressed platelet function. In general, the time course and dose-dependence of the effects of the injected antibodies were correlated with bleeding time, platelet aggregation and platelet-bound antibody titers.
This study indicated that a murine monoclonal antibody that inhibits platelet aggregation in vitro could suppress platelet function in vivo without inducing spontaneous hemorrhage or marked thrombocytopenia.

抄録全体を表示

von Willebrand factor (vWf) is well known to interact with platelet membrane glycoprotein Ib (GPIb) in the presence of botrocetin as well as ristocetin. We studied the role of botrocetin on vWf binding to GPIb. The amount of vWf binding to GPIb was dependent on the concentration of botrocetin. Labeled botrocetin showed the specific binding to vWf and its tryptic fragments of 116kDa and 52/48kDa (residues 449-728). 116kDa fragment was a homodimer of 52/48kDa fragment. III-T2 fragment, also dimer, was composed of two pairs of disulfide-linked subunits, two 35-kDa heavy chains (residues 273-511) and two 10-kDa light chains (residues 674-728) and failed to bind to botrocetin. These results strongly suggest that the missing portion of III-T2 fragment corresponding to the amino acid residue from 512 to 673, is crucial for the binding domain of botrocetin. The synthetic peptides of vWf and anti-vWf monoclonal antibodies that inhibit the ristocetin-induced vWf binding to GPIb, failed to inhibit the binding in the presence of botrocetin, whereas glycocalicin and anti-GPIb antibody inhibited the binding in the presence of both botrocetin and ristocetin. These data strongly suggest that vWf binds to GPIb after the conformational change of vWf by the binding to botrocetin.

抄録全体を表示

In order to elucidate the relationship between antiphospholipid antibody (APLA) and thrombotic tendency, we studied the changes in the blood coagulation system in 31 positive APLA patients using thrombin-antithrombin III complex (TAT) and β-thromboglobulin (β-TG), two sensitive molecular markers for in vivo hypercoagulability.
The mean plasma levels of TAT and β-TG in the patients were not significantly elevated when compared with those in healthy subjects. And also they were not significantly correlated with anti-cardiolipin antibody titers. In two cases of the patients, plasma levels of TAT and β-TG were serially measured as the underlying disease activities went on. In spite of the disease progression, no significant changes in both plasma TAT and β-TG levels were observed. In one case of the two, however, deep vein thrombosis occurred at a markedly advanced stage of the underlying disease with a rapid increase in both plasma TAT and β-TG levels.
These findings suggest that the presence of APLA per se would not directly correlate with in vivo generation of thrombin or platelet activation, but would be an important precipitating factor of thrombus formation under a physical condition closely associated with thrombin generation and/or platelet activation.

抄録全体を表示

Liver disease is associated with complex coagulation and fibrinolytic defects. In this study we assayed molecular marker levels for coagulation and fibrinolysis, i. e. plasma fibrinopeptide A (FPA), fibrinopeptide Bβ_1-42 (Bβ_1-42), fibrino peptide Bβ_15-42 (Bβ_15-42), tissue-type plasminogen activator antigen (t-PA antigen) and activity (t-PA activity), plasminogen activator inhibitor (PAI), D-dimer, plasminogen, α₂ plasmin inhibitor (α₂ PI), α₂ PI-plasmin-complex (PIC), ATIII and serum FDP-E in 31 patients with liver cirrhosis for investigated the state of coagulation and fibrinolyssis in liver cirrhosis.
All these molecular markers changed significantly compared with the value in normal subjects. As for coagulation, hypercoagulable state was observed because of increment FPA level and one of the reasons of this state maight be decrease of ATIII synthesis. As for fibrinolytic state, accelerated fibrinolysis was observed because of increment of PIC, Bβ_1-42, D-dimer, FDP-E, Bβ_15-42. In addition, these changes might be induced through accelerated secondary fibrinolysis, increment of t-PA by decleased clearance of circulating PA and diminished α₂ PI synthesis.
And the variation of t-PA antigen level was well correlated to plasminogen, α₂ PI, ATIII and Ch-E, measuring of t-PA antigen level was useful to evaluate liver function in the patients with liver cirrhosis.

抄録全体を表示

We have already reported about fluctuations of tissue plasminogen activator (t-PA) activity, t-PA antigen, plasminogen activator inhibitor-1 (PAI-1) antigen and t-PA index ((t-PA activity ng/ml)/(t-PA antigen ng/ml)×100) in blood obtained from patients with acute cerebral infarction (CI).
Most patients were plotted out to the abnormal range by a scattergram relating t-PA activity to t-PA antigen, and showed a powerful correlation between PAI-1 inhibitor and t-PA index, suggesting the influential regulation of PAI-1. In this report, we designed to investigate the fibrinolytic parameters, including t-PA activity, t-PA antigen, PAI-1 antigen, t-PA index and T/P 100 ((t-PA antigen ng/ml)/(PAI-1 antgen ng/ml)×100) in acute phase of a first-time or recurrent CI, and chronic one.
The results were as follows: the mean value of t-PA activity, t-PA antigen, t-PA index, PAI-1 antigen and T/P100 were higher than those of healthy controls. Although no significant differences were shown between these fibrinolytic parameters of a first CI and a reinfarction, chronic CI presented significantly higher t-PA activity than a first orrecur-rent acute CI. It is considered to be important to clarify pathophysiological differences of fibrinolytic mechanism between acute and chronic CI.

抄録全体を表示

We measured the plasma levels of plasminogen activators (tPA, uPA) and their inhibitors (PAI-1, PAI-2) at various intervals during pregnancy, delivery and puerperium. Their antigens were measured by Biopool Tint Elize Kits. In the pregnancy plasma of the third trimester, the levels of the activators were about 2 times and those of their inhibitors were about 10 times higher than those in non-pregnancy plasma.
To clarify whether the uterus and/or placenta are involved in the increased levels of plasma PA and their inhibitors, their levels were measured in the retroplacental blood (RPB) and the uterine venous blood (UVB). The level of tPA in the RPB was the same as that in the peripheral venous blood (PVB) but the levels of uPA, PAI-1 and PAI-2 in the RPB was about 2.5 times higher than those in the PVB. During the ante-partum period, only the level of uPA in the UVB was higher than that in the PVB, while there was no significant difference between the levels of tPA, PAI-1 and PAI-2 in the PVB and UVB. The level of tPA in the UVB rose after separation of placenta. In contrast, the level of uPA declined immediately after the separation. There was no significant difference between the levels of PAI-1 and PAI-2 in the UVB before and after removal of the placenta.
The release of tPA from endotherial cell was enhanced in vitro by addition of the pregnancy plasmas obtained at the time of delivery.
These results suggest that placenta, uterus and entire vascular system are involved in the increase of tPA and uPA during pregnancy but that the major source of their inhibitors in the pregnancy plasma are unknown.

抄録全体を表示

Coagulation-fibrinolytic abnormalities in patients were investigated by newly developed bioimmunoassay method for t-PA activity, t-PA antigen (ETA), plasminogen activator inhibitor-1 (PAI-1) and various coagulation-fibrinolytic molecular markers. Plasma levels of t-PA antigen were markedly increased in severe liver diseases involving decompensated liver cirrhosis, hepatocellular carcinoma and fulminant hepatitis. Plasma levels of t-PA activity, however, varied from low to high levels. Consequently, the ratio of t-PA activity versus antigen decreased markedly in the severe state. It was revealed that the majority of increased plasma t-PA antigen obtained from severe liver diseases actually consisted mainly of complexes of t-PA and PAI-1.
After trans-catheter embolization (TAE) therapy for patients with hepatocellular carcinoma, plasma levels of t-PA activity immediately increased and reached peak levels within 6 hours, while symmetrical decreases in PAI-1 were observed. On the other hand, the levels of D-dimer, plasmin-alpha 2 plasmin inhibitor complex (PIC), thrombin-antithrombin 3 complex (TAT) subsequently increased in plasma following the increase in t-PA and decrease in PAI-1. Therefore, plasma t-PA activities evaluated by this bioimmunoassay were considered to be a sensitive indicator of fibrinolysis activation.
Plasma t-PA activity in various liver diseases had significant positive correlation with PIC levels, and negative correlation with PAI-1. However, t-PA activities had no correlation with levels of t-PA antigen, TAT, and D-dimer. It is difficult to correctly evaluate coagulation-fibrinolytic condition with limited specific markers. It was concluded that combination assay for t-PA activity, t-PA antigen, PAI-1 and other molecular markers is required to assess the coagulation-fibrinolytic condition in severe liver diseases.

抄録全体を表示

Twelve patients with hemophagocytic syndrome (HPS), were studied. In these patients, marked hemophagocytosis was observed with fever in 10, hepatosplenomegaly in 11, and organ failure and disseminated intravascular coagulation (DIC) in 10 each. Six of these patients were treated, and only 2 have survived with 10 having died. The time of survival was within 3 months in most cases. Pancytopenia was noted in all patients, and GOT, LDH, total bilirubin, and creatinine were increased in many patients. Coagulation examinations showed a marked prolongation of APTT in 2, prolongation of prothrombin time in 3, and high fibrinogen levels in many patients. Increased FDP and thrombocytopenia were noted in most patients, and antithrombin III activity was reduced in half the patients. Organ failure was more frequent than bleeding tendency. Tissue plasminogen activator antigen and plasminogen activator inhibitor (PAI) -1 antigen levels were markedly increased, and the PAI-2 antigen level was slightly increased. Plasma interleukin (IL) -1β, granulocyte macrophage colony stimulating factor, and IL-6 levels were elevated. Thus, HPS was frequently complicated by multiple organ failure due to activation of monocytes/macrophages, hypercytokinemia, and an increase in PAI. Examination of monocyte-specific markers is considered to be useful.

抄録全体を表示

A case of prostatic cancer associated with DIC was reported. On admission, the patient was in hypercoagulable state. On 9th hospital day, he developed a decompensated DIC in association with a high fever. The origin of the fever was thought to be an abscess of the right thigh. After the treatment of the infection with antibiotics, the patient was cured of decompensated DIC without anticoagulant therapy.

抄録全体を表示