It had been previously reported that platelet-clumping substance (PCS) appeared after acidification of heparinized plasma of rabbit. The pH in acidification was around 6.0 which was observed in ischemic or inflammatory lesions in vivo. As the chemical structure is still not determined, we tried to isolate it from rabbit plasma. Citrated rabbit plasma was mixed with 100U/ml of heparin and 0.1M CaCl₂, and was centrifuged at 10, 000×g for 30 minutes to obtain clumping activity in the precipitate. The precipitate was soluble in 20mM Tris-HCl containing 1M KBr pH 7.4 (high salt buffer), while fine aggregates of plasma proteins were observed in 20mM Tris-HCl without 1M KBr (low salt buffer). The dissolved material was applied to the Sapharose 6B column, and the clumping activity was eluted between the void volume and albumin fractions. The molecular weight was estimated to be about 800, 000. The fractions contained 3-4 bands in the globulin fraction on 7.5% polyacrylamide electrophoresis. Heparin was not detected in these PCS fractions by metachromatic staining on 6% agarose electrophoresis. The clumping activity was adsorbed on the fibrin monomeraffinity column. After the immunization of the active fraction to guinea-pig, the antiserum prevented platelet aggregation induced by PCS. The antiserum showed an identical precipitation line against PCS fraction as anti-fibrinogen antiserum. These results suggest that platelet-clumping substance may be composed of aggregated plasma proteins which mainly contained fibrinogen-fibrin.

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The intravascular platelet aggregation and the subsequent thrombus formation were found to be induced in the microvasculature by the irradiation of filtered light in combination with the intravascular administration of fluorescein sodium. Effects of several factors such as light intensity, dye concentration and vessel diameter were examined in venules of rat mesenteries. It was confirmed that the platelet thrombus was induced with excellent reproducibility depending on the combined condition of the light intensity and the dye concentration. In venules within the range of 20 to 80μm in diameter, almost the same values of the initiation time of thrombus formation were obtaind. On the other hand, the time to totally occlude the vessel lumen by the thrombus prolonged significantly with the increase of vessel diameter, which phenomenon seemed to be induced by almost the same growth rate of thrombus in the radial direction in all venules with different diameters. Inhibitory effects of prostaglandins (PGD₂, PGE₁) for the thrombus formation were also examined by the proposed model. The platelet aggregation in venules was significantly inhibited by higher concentration of these doses. This result well corresponded to that of in vitro experiments reported by other researchers. The present model seems useful for various purposes in studying the kinetics of intravascular thrombus formation as well as evaluating the effects of anti-platelet aggregating drugs.

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Two family members (daughter and mother) with a bleeding disorder showed prolonged bleeding time and activated partial thromboplastin time associated with decreased plasma levels of factor VIII procoagulant activity, factor VIII-related antigen and von Willebrand factor (vWf). The ristocetin-induced platelet agglutination was enhanced, but collagen- and Ca ionophore-induced platelet aggregation were also increased at their low concentrations. Contrary to the type II B von Willebrand's disease (vWd), pseudo-vWd and platelet-type vWd, they did not show any increased binding of factor VIII/vWf to platelets in the presence of ristocetin. In addition, when a small amount of normal plasma was added to the washed platelets suspension at a sufficient concentration of ristocetin and when a low concentration of ristocetin was added to the washed platelets suspension at a sufficient amount of normal plasma, their platelets were more aggregated than normal platelets. In this atypical vWd, therefore, the hyper-reactivity of platelet aggregation may be due to an intrinsic platelet abnormalitiy, not due to enhanced interaction between plasma factor VIII/vWf and platelets.

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Kawasaki disease affects children under four years of age and is an acute inflammatory disease with systemic vasculitis. Kawasaki disease is associated with a high incidence of cardiovascular complications such as thrombotic occlusion and aneurysm of the coronary arteries. Thromboxane A₂ has the action of vasoconstriction, and increases platelet aggregability. Thromboxane A₂ is readily metabolized to the inactive thromboxane B₂. The authors measured the levels of plasma thromboxane B₂ in the initial stage of Kawasaki disease. Plasma thromboxane B₂ level in nomal subjects was 0.28±0.19ng/ml (mean±SD; n=10). Plasma thromboxane B₂ level in patients with Kawasaki disease before treatment, was 0.33±0.21ng/ml (mean±SD; n=27). Patients with coronary aneurysm had markedly increased plasma thromboxane B₂ levels (2.02±0.84ng/ml; n=7). Elevation of plasma thromboxane B₂ levels indicates that there is the possibility of endothelial injury and aneurysm formation.
It is possible that the endothelial injury caused by angitis in Kawasaki disease leads to cardiovascular complications and juvenile atherosclerosis. We measured the serum elastase activity which has antiarteriosclerotic action and its beneficial effect on cholesterol and lipoprotein. We measured the serum elastase activity in nineteen patients with Kawasaki disease during twenty-eight days after the onset of illness. The enzyme activity was measured by the spectrophotometric measurement of elastase using succinyl-trialanyl-p-nitroanilide as a substrate, and by the immunoreactivity Elastase-I RIA kit (Dainabot).
Patients were classified into two types which were based on enzyme activity; namely, one type with increasing serum elastase activity, another type with decreasing serum elastase activity with the passage of time. The latter type tended to the development of coronary aneurysm.
These results suggested that the cases of decreasing serum elastase activity were associated with vascular wall weakness and abnormal lipid metabolism in Kawasaki disease.

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In order to clarify the etiological factor of late occlusion in peripheral arterial reconstructions, PGI₂ activity of luminal surface of autogenous vein grafts implanted to the canine femoral artery was investigated 30 days after implantation and was compared with those of canine normal femoral artery and vein. To obtain PGI₂ extract from vascular specimens, borate buffer saline (pH 9.0) was infused into the lumen of the vascular specimens and incubated in vivo for 30 minutes. PGI₂ activity of the extract was measured based upon its inhibitory activity of ADP induced platelet aggregation. PGI₂ activity of luminal surface of the autogenous vein grafts was 7.66±5.56ng/cm² (n=5) and the value was significantly lower than that of normal femoral arteries (45.89±11.61ng/cm², n=5), and lower than that of normal femoral veins (11.86±6.91ng/cm², n=5).
The results suggest that decrease of PGI₂ activity of the luminal surface of autogenous vein graft may be responsible for the late occlusion in peripheral arterial reconstruction.

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Fibrin monomer is formed by the action of thrombin or snake venom on fibrinogen molecule, and it was regarded that its presence in blood indicates the hypercoagulability. The principle of fibrin monomer test (FMT) is that the formalin-fixed human red blood cells (RBC) coated with fibrin monomer (FM) form RBC aggregation, probably by forming bridges between soluble FM and FM-coated RBC.
Simultaneous and day-to-day reproduciblities of FMT were found excellent and its sensitivity to FM was determined to be as low as 2.5μg/ml. The FMT was negative to fibrinogen but positive to fractions containing FM complexes in the void volume of the column, when FM containing plasma was chromatographed by gel filtration on a Biogel A-15m column.
In the process of dissolution of non-crosslinked fibrin by plasmin, the FMT was strongly positive to the specimen obtained immediately after the complete lysis of the clot, when large amounts of high molecular weight complexes of fibrin and early FDP were still present. Reactivities were found to be reduced or even negative to the specimens obtained after further degradation.
An electrophoretic analysis using 5% polyacrylamide gels of these serial specimens revealed that FMT was positive as long as the βand γ chains retained their original molecular integrities nearly completely. Closslinking of fibrin did not affect the results.
It was concluded that FMT was specifically positive to fibrin monomer and early stage products of fibrin degradation, i. e, fibrinogen metabolites formed in the process of hypercoagulability. The method was simple, reproducible and sufficiently reliable in detecting the hypercoagulable state of blood.

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The thrombus formation during extracorporeal circulation (ECC) and the effectiveness of the pretreatment with antiplatelet drugs were investigated.
Forty-three patients who underwent valvular surgery were divided into four groups: Group A; control, Group B; dipyridamole 300mg/day, Group C; ticlopidine 300mg/day, Group D; ticlopidine 600mg/day, each drug was administered orally for seven days continuously before operation. Using the electron microscopy, we observed the inner surfaces of the bubble oxygenator after surgery, and evaluate the extent of the deposits of thrombi on those surfaces. And also the platelet-microaggregates were examined by evaluating the size-distribution of the platelets of the circulating blood. Results: In group A, all samples of the surfaces of the oxygenators were covered in layers with huge thrombi or platelet aggregates. On the contrary in groups B, C, and D, almost all surfaces of the oxygenators were kept bare with few adhesion of thrombi or platelet-microaggregates. As for platelets size-distribution, in group A, both used or consumed platelets, namely, small size platelets (1-4m³) and the platelet aggregates (25μm³<) increased along the duration of the time of the ECC. Meanwhile in group C and D, both small size and extremely large size platelet aggregates were kept in steady level and did not show any increase during ECC. It means that the pretreatment with antiplatelet drugs is an useful and effective method to prevent the thrombus formation during ECC. And also no increase in the postoperative blood loss or no bleeding tendency after operation were induced by the pretreatment with antiplatelet drugs.

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In the preliminary repory, we have demonstrated that the supernatant obtaind by centrifugation at 10, 000xg from human placental extracts shows a potent inhibitory effect on platelet aggregation, and that placental protein (PP5; Bohn, 1977) has also an inhibitory effect of platelet aggregation as well. In this report, the two contrary effects on platelet aggregation were found in the process of the purification of platelet antiaggregatory substances from human placental extracts.
Results; 1) The supernatant obtained at 10, 000xg for 15min, and the precipitate obtained at 104, 000xg for 60min. from human placental extracts showed the strong inhibitory effects on platelet aggregation which was prominent in the precipitate of microsomal fraction. 2) A definite fraction of the supernatant obtaind at 104, 000xg for 60min, after gel-filtrayion showed an acceleration of platelet aggregation. 3) Although PP5 was demonstrated in the supernatants at 10, 000xg for 15min. and at 104, 000xg for 60min. by the use of an immunoperoxidase technique, PP5 was not found in the precipitate at 104, 000xg for 60min.
In conclusion, it is evident that there are least two contrary substances showing inhibition and stimulation on platelet aggregation in human placental extracts.

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Recently, it has been accepted that myosin and actin play an important role in thrombus formation. But, there are many unknown problems about behavior of myosin and actin following activation of platelets. In this paper, we purified human platelet myosin, prepared specific rabbit antibodies agaist human platelet myosin and investigated about immunological characteristics of the antibodies and histochemical behavior of intracellular myosin during ADP-induced platelets aggregation.
The results were as follows; 1) The obtained antibodies did not react with human striated muscle myosin, but reacted with human smooth muscle (carotid arteries and uterus) myosin and porcine platelet myosin. However, the antibodies did not react with light chains of porcine platelet myosin. Therefore, the antibodies seemed to be antibodies against heavy chain of myosin. 2) Using the antidodies, the indirect immunofluorescence microscopy of human platelets showed that myosin were distributed almost homogenously in the cytoplasm of both non-activated and ADP-activated platelets.
In summary, it was shown that human platelet myosin possessed common antigenesity to the smooth muscle myosin and was homogenously located in cytoplasm of platelets. However, in order to clarify dynamic behavior of myosin in activated platelets a new method for the study should be developed.

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We reviewed 16 records of death cases with perforated peritonitis or leakage of gastrointestinal anastomoses at the Second Department of Surgery, Toho University Hospital, from 1977 to 1981. In this study, correlationship between disseminated intravascular coagulation syndrome (DIC) and multiple organ failure syndrome (MOF) was investigated.
MOF occured in all cases and DIC occured in 11 out of 16 cases. The cases of DIC had major organ failure and developed MOF. DIC was initial organ failure in 6 cases out of 16 MOF cases. These results suggested that there are some cases of MOF as result of DIC. But, it is fact that there are some cases of DIC due to organ failure. In this cases DIC may be developmental factor of MOF.
We observed closely correlationship between DIC and renal or respiratory failure. DIC and MOF may be identical syndrome in some cases.
Earlier treatment of organ failure is important for clinical management of DIC.

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To evaluate the clinical efficacy of administration of high dose of urokinase in acute myocardial infarction, we deviled the patients into three groups (high, moderate, and low dose of urokinase). Dose of intravenously dripping urokinase is less than 50×10⁴ unit in low dose group (Group A), 50×10⁴-150×10⁴ unit in moderate dose group (Group B), and 150×10⁴-300×10⁴ unit in high does group (Group C). Following clinical data was examined; 1) serum CPK 2) size of myocardial infarct area (ΣST of ECG) 3) aneurysmal formation and asynergy 4) hemodynamic factors (CI, PAEDP, SWI, TPRI and Double Product).
There was no significant difference in normalizing days of serum CPK between Group A and Group C. Concerning percent changes of ΣST, decrease rate was significantly larger in Group C than in other Group on the 1.5th hospital days (p<0.05) and on the 3rd days (p<0.01) after administration of urokinase. In Group C, aneurysmal formation was not seen and less score of asynergy (AHA criteria) revealed in left ventricular angiogram. Though CI, PAEDP and SWI were more improved in 7 hospital days in Group C than in other groups, there was no difference in TPRI and DP among three groups.
We conclude that high dose of urokinase is effective on reduction of infarct area and amelioration of cardiac function in acute myocardial infarcion.

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