The effect of recombinant human single-chain tissue-type plasminogen activator (MMR701) on the patency rate of infarct-related coronary arteries was investigated in anesthetized dogs with coronary thrombi induced by inserting a copper coil into the left anterior descending coronary artery (LAD). The efficacy of MMR701 in six regimens was evaluated by continuous intravenous infusion over 60 minutes alone (Regimen A-C), and then in combination with various initial intravenous bolus injections (Regimen D-F). In the former experiments, patency was respectively observed in 60%, 100%, and 100% of 5 dogs infused for 60 minutes with 150IU/kg/min (Regimen A), 500IU/kg/min (Regimen B), and 1500IU/kg/min (Regimen C) of MMR701. Both the time needed for achieving patency and the weight of undissolved thrombi in the vessels decreased dose-dependently. In the latter experiments, four dosage regimens (Regimen A and Regimen D-F) with different bolus/infusion ratios were compared using equal amounts (9000IU/kg) of MMR701, in order to evaluate the optimal therapeutic regimen of MMR701. Among regimens with an initial bolus injection of 0% (Regimen A), 10% (Regimen D), 50% (Regimen E), or 90% (Regimen F) of the total amount used and subsequent continuous infusion of the remaining amount over 60 minutes, the regimen with an initial 10% bolus (Regimen D) was the most effective, achieving the highest rate of patency (100%), shortest time needed for achieving patency, and highest thrombolytic activity. Plasma levels of fibrinolytic and hemostatic parameters, such as α2-plasmin inhibitor, plasminogen, and fibrinogen, were not decreased significantly in all regimens. It is concluded that MMR701 produces a thrombolytic effect with no remarkable disorders of the fibrinolytic and hemostatic systems in the canine myocardial infarction model. It is also suggested that the regimen with a 10% bolus injection may have a great advantage in the treatment of acute myocardial infarction.
The levels of tissue plasminogen activator (t-PA) antigen, PA activity, plasminogen activator inhibitor 1 (PAI-1) antigen, PAI activity and t-PA·PAI-1 complex were measured in normal plasma or serum obtained by different methods. PA activity could be measured only in acidified plasma samples. Plasma and serum t-PA antigen levels were equivalent. PAI activity and PAI-1 antigen levels elevated during incubation of citrated blood at 37°C for one hour. Marked elevations of the levels of PAI-1 antigen, PAI activity and t-PA·PAI-1 complex were found in serum. These findings indicate that prolonged storage of anti-coagulated blood leads to the release of PAI-1 from platelets, and that some of the released PAI-1 are active. However, no change was found in plasma levels of PAI-1 antigen, PAI activity and t-PA·PAI-1 complex if citrated blood samples were centrifuged immediately at 4°C either when antiplatelet agents were added for blood collection or not. Therefore, the levels of PAI-1 antigen, PAI activity and t-PA·PAI-1 complex would be determined precisely in the routinely used citrated plasma if citrated blood is centrifuged immediately after blood collection.
Platelet function in a strain of rabbits designated as Watanabe heritable hyperlipidemic (WHHL) rabbits was examined. When compared to normolipidemic rabbits, the platelet aggregation induced by ADP and collagen were significantly higher in WHHL rabbits (P<0.01 or 0.05). Furthermore, platelet sensitivity for ADP was significantly higher in WHHL rabbits than in normolipidemic rabbits (P<0.01). The platelet aggregation among resuspended platelet in normolipidemic rabbit plasma was singnificantly higher in WHHL rabbits than in the normolipidemic rabbits (P<0.01). Furthermore, the botrocetin induced platelet agglutination (BIPA) as von Willebrand factor (vWF) activity was significantly higher in WHHL rabbits than in normolipidemic rabbits (P<0.01). As for change of platelet function with aging, the platelet aggregation induced by ADP increased with age and the BIPA were higher in WHHL rabbits than control rabbits at almost all ages and decreased between 5 and 8 months of age. These findings suggest that increased platelet function and vWF activity in WHHL rabbits are associated with the thrombotic complications and accelerated atherogenesis of WHHL rabbits.
Na+/H+ exchangers mediate intracellular pH ([pH] i) in various preparations containing platelets. In other cells C kinase, cyclic AMP, Ca2+, and guanine nucleotide proteins (G-proteins) are thought as the possible passway, but the mechanism is not clear in platelets. It is known that sodium fluoride (NaF) activates G-proteins and NaF itself induces platelet aggregation. This time, we have investigated whether NaF induced changes in [pH]i to make sure of regulation of G-proteins for Na+/H+ exchangers, comparing changes in the intracellular calcium ion concentration ([Ca2+] i), C kinase and cyclic AMP. NaF caused platelet aggregation through the elevation of [Ca2+] i. Stimulation of thrombin resulted in increase in [pH] i through the elevation of [Ca2+] i, but NaF failed to raise the [pH] i, and a low concentration of NaF, which did not cause aggregation, inhibited thrombin-induced increase in [pH] i but did not inhibit thrombin-induced increase in [Ca2+] i, C kinase activation or cyclic AMP. These results suggest that NaF has an inhibitory effect on Na+/H+ exchangers via G-proteins and that an increase in [pH]i is not needed for an increase in [Ca2+] i.
The levels of protein C (PC) and protein S (PS) were assessed in plasmas derived from 39 patients with various chronic liver diseases and found to be significantly decreased. These decreased levels were positively correlated with the parameters for the protein synthesis in the liver, including cholinesterase, serum albmin, and hepaplastin test, suggesting that the synthesis of PC and PS were also decreased in these diseases. Interestingly, the patients with increased levels of T·AT and manifested decreased PC and PS levels in plasma. These inverse correlations seem to indicate that the decreased levels of PC and PS in plasma could precipitate the disseminated intravascular coagulation syndrome by virtue of insufficient regulation of accelerated blood coagulation.
In 12 patients with nephrotic syndrome, the moleclar markers for hypercoagulability including thrombin-antithrombin III complex (TAT), plasmin-α2-plasmin inhibitor complex (PIC) and β-thromboglobulin (β-TG), and the coagulation regulatory factors including antithrombin III (AT III), heparin cofactor II (HC II), protein C (PC) and protein S (PS) were studied. Plasma levels of TAT, PIC and β-TG were all significantly high as compared to normal controls, and also they were inversely correlated with serum albumin levels and positively correlated with total urine protein levels. In the antithrombin-regulatory system, AT III was found decreased and significantly correlated with serum albumin and total urine protein levels, while HC II was rather increased when compard with normal controls. In the PC-regulatory system, PC was significantly increased, while PS activity was significantly reduced as compared to normal controls, and they were significantly correlated with total urine protein levels. Decreased PS activity was caused mainly by significant reduction in free (active) PS levels due to the selective and massive urinary loss of free PS and the elevation of C4b-binding protein (C4bp) levels which favor complex formation (C4bp-PS) with free PS. These results imply that the thrombotic tendency in nephrotic syndrome might be raised in parallel with the progression of disease activity, and high levels of PC and HC II would help to counteract hypercoagulability.
This study is to establish the measurement of urinary FDP-E using latex photometric immunoassay (LPIA). pH values of urine and urinary substances such as albumin, glucose, urea, bilirubin, ascorbic acid and hemoglobin did not affect the measurement of urinary FDP-E (Fig. 1-3). Urinary FDP-E concentrations were not changed after storage for 7 days at room temperature and for 28 days at 4°C, -20°C, -80°C, both with and without 0.1mol of transaminocaprinic acid (Fig. 4). Normal values of urinary FDP-E are 0.27±0.31ng/ml (N=36), 264.52±310.38ng/day (N=35) (Fig. 5). These results suggested: (1) Urinary FDP-E can be measured without any disturbance by pH, and abnormal substance which were excreted into urine. (2) Storages of urine for 7 days at room temperature and 28 days below 4°C did not affect the measurement of urinary FDP-E.
The endometrium is a site of high fibrinolytic activity associated with menstruation, nidation of ovum and wound healing. To investigate the fibrinolytic system in the endometrium and the influence of sex steroids on it, tissue type plasminogen activator (t-PA) antigen, plasminogen activator inhibitor 1 (PAI-1) antigen and PA activity in the conditioned medium of the endometrial fibroblastoid cells (EF) cultured in the presence of these hormones were assayed. The growth rates on the fibrin gel substrate were also assayed. t-PA synthesis and PA activity were enhanced by estrogen. PAI-1 synthesis was increased and PA activity was suppressed by progestrone (P), estradiol (E2)+P, testosterone, dexamethasone and indomethacine. The cells were well proliferated on the fibrin substrate and no aggregation were observed in the case of high level PAI-1. E2 brought about cell aggregation and cessation of growth due to the substrate degradation accelerated by t-PA. It was suggested that the fibrinolytic system in the endometrium was controlled by sex steroids through the balance of PA and PAI synthesis.
Two cases of Idiopathic vitamin K deficiency in infancy we experienced recently are reported. The first case was admitted to Kanagawa Children's Medical Center at 62 days of age, because of intracranial hemorrhage due to vitamin K (VK) deficiency. She fell ill in spite of prophylactic administration of oral VK at her birth and 6 days after birth. She exhibited hyperbilirubinemia and elevation of serum transaminase. It was suspected that Cytomegalovirus (CMV) infection was related to her liver dysfunction, because IgM antibody to CMV was increased and CMV was isolated from her urine and breast milk of her mother. The second case was admitted at 31 days of age, and made a diagnosis of subdural hemorrhage and hemothorax due to VK deficiency. He had not received VK administration prophylacticaly, because his Normotest was normal at 6 days of age. He exhibited slight elevation of serum transaminase on admission. However CMV infection could not be elucidated in this case. We think that liver dysfunction plays important role in the onset of VK deficiency in infancy. The prophylactic administration of VK during the neonatal period has been carried out widely in Japan, and a remarkable decrease of intracranial hemorrhage due to Idiopathic VK deficiency in infancy has been reported. It is important to study the cases that failed to be prevented, for making a plan to prevent VK deficiency in infancy furthermore.
As desmopressin (DDAVP) has gained wide acceptance as the first choice treatment in perioperative management of patients with von Willebrand disease (vWD) type I, DDAVP was administered 30min prior to total thyroidectomy of a vWD patient. Response of factor VIII coagulant activity (VIIIc) and ristocetin cofactor (RcoF) to DDAVP was slow and the maximum levels were obtained 6 hours after infusion (VIIIc: 0.48 to 2.05U/ml and RcoF: 0.44 to 0.98U/ml). VIIIc and RcoF returned to the preinfusion level 48 hours and 4 days after DDAVP administration, respectively. No further DDAVP was necessary because of this prolonged response and no remarkable postoperative hemorrhage. Response to the second DDAVP administration, performed at the removal of drain tubes, 7 days after the surgery, showed almost identical elevation of both activities (increased range, VIIIc: 2-fold and RcoF: 2.7-fold). VIIIc returned to the preinfusion level after 18 hours and RcoF activity showed still high level at that time. The delayed and prolonged response of these factors to DDAVP during the surgery would be derived from the effect of the surgical procedures and the anesthesia.