Akikazu Takada

Relationship between age and plasma t-PA, PA-inhibitor, and PA activity

A positive correlation between age and the occurrence of thrombosis has been suggested. We studied the relationship between age and fibrinolytic activities; namely levels of tissue plasminogen activator (t-PA) antigen, plasminogen activator inhibitor (PA inhibitor) activity, and plasminogen activator activity (PA activity). A dramatic increase in both t-PA antigen and PA inhibitor was shown in persons with increasing age. PA activity decreased with age. Therefore it is suggested that the tendency of decreased PA activity with increasing age may be related to the high incidence of thrombosis in older persons.

Characterization of various antibodies against tissue plasminogen activator using highly sensitive enzyme immunoassay

Polyclonal and three monoclonal anti-tissue plasminogen activator (a-t-PA) antibodies (1:3 C5, 1:3 G5 and 2:2 B10) were characterized by using enzyme immunoassay (EIA) in which beta-D-galactosidase was coupled to a-t-PA antibody. Monoclonal antibodies called 2:2 B10 and 1:3 G5, specific for both one-chain and two-chain t-PA, strongly bound to one-chain t-PA purified from cultured melanoma cell lines, but 1:3 C5 antibody bound weakly to such t-PA. When polyclonal t-PA antibody was used as the first reaction antibody immobilized on silicone pieces, few determinants were available for monoclonal antibody used in the second reaction due to previous interaction of these determinants in the first reaction. When t-PA levels in the plasma were determined, the presence of EDTA enhanced the sensitivity of t-PA determination by the present EIA technique. Plasma concentrations of t-PA were measured to be higher with 2:2 B10 monoclonal antibody than with polyclonal antibody as the first antibody. Tissue-PA was mainly detected in the endothelial cells, but not in the muscular layer of the inferior mesenteric artery when immunochemical technique was used with polyclonal t-PA antibody.

THE CONCENTRATION OF TISSUE PLASMINOGEN ACTIVATOR AND UROKINASE IN PLASMA AND TISSUES OF PATIENTS WITH OVARIAN AND UTERINE TUMORS

The concentrations of tissue plasminogen activator (t-PA) and urokinase (UK) were measured in the plasma of patients with benign or malignant ovarian and uterine tumors. Plasma levels of t-PA were higher in patients with malignant ovarian and uterine tumors than in patients with benign tumors. Plasma UK levels were, however, not different between patients with ovarian and uterine tumors (benign or malignant) and normal persons. The concentrations of t-PA and UK of tissues of uterine myoma were lower than those in normal uterine muscular layer. UK levels of tissues of endometrial and cervical cancers were significantly higher than those in normal endometrium and uterine cervix, whereas t-PA levels were not different between these tumors compared with those in normal uterine tissues.

Changes of parameters in fibrinolytic system caused by mental stress

Physical and/or mental stress are reported to influence the activity in coagulation and fibrinolytic system by several investigators (l-6). Physical stress is widely known to stimulate the release of tissue plasminogen activator from the endothelial cells, which results in marked increase in fibrinolytic activity. The mechanism of mental stress to affect the fibrinolytic system, however, is not fully analyzed. In the present study, we employed the popular laboratory test of bleeding time (Duke method) (7) as the initiator of mental stress, since the procedure itself is fearful for the examinee due to the fact that the examinee can not see the procedure of incision to ear directly. So we analyzed the effects of incision procedure on the fibrinolytic system by measuring plasma levels of fibrinolytic parameters and clot lysis.

Prevention of severe bleeding by tranexamic acid in a patient with disseminated intravascular coagulation

Severe bleeding took place in a patient when abdominal aneurysm was removed by operation. Bleeding continued after infusion of heparin, antithrombin III (ATIII), fresh platelets and fresh blood. Infusion of tranexamic acid resulted in an immediate cessation of bleeding and improvement of his general condition. Sometime after the cessation by the administration of tranexamic acid, severe bleeding started again, resulting in intraperitoneal hematoma formation. Second time bleeding also stopped after the administration of tranexamic acid. Major finding of plasma parameters of fibrinolysis is that alpha 2AP which had been unable to inhibit plasmin, became able to inhibit it after the administration of tranexamic acid.

Fluctuations of euglobulin lysis time, tissue plasminogen activator, and free and total plasminogen activator inhibitor levels in plasma in daytime

Blood was taken from healthy 15 males and 10 females at 9:30 h, 10:00 h and 12:30 h. The euglobulin fraction was prepared and clotted by the addition of human thrombin. The clot lysis time shortened significantly from 9:30 h to 10:00 h (p less than 0.01) and further to 12:30 h (p less than 0.01). Plasma levels of tissue plasminogen activator (t-PA) antigens did not change from 9:30 h to 10:00 h, but slightly and significantly to 12:30 h (p less than 0.01). Plasma levels of free plasminogen activator inhibitor-1 (PAI-1) and complex of t-PA-PAI-1 decreased from 9:30 h to 10:00 h (p less than 0.02) and to 12:30 h (p less than 0.01). Plasma levels of total PAI-1 (free plus complex) decreased from 9:30 h to 10:00 h (p less than 0.01) and to 12:30 h (p less than 0.01). These results suggest that a major factor contributing to the enhanced fibrinolytic activity of the euglobulin fraction may be a level of PAI-1 (free and total).

Measurement of Urinary Trypsin Inhibitor in Urine, Plasma and Cancer Tissues of Patients with Stomach Cancer

Antiserum was obtained from rabbits immunized with a highly purified preparation of urinary trypsin inhibitor (UTI) conjugated with rabbit serum albumin. Anti-UTI antibody did not cross-react with antibody against inter-alpha-trypsin inhibitor (I alpha I) as determined by immunodiffusion against human plasma. A highly sensitive enzyme immunoassay was developed for the determination of UTI-related antigens (UTIR) in plasma, urine and cancer tissues. The level of UTIR correlated with UTI activity in urine. UTIR levels in urine and plasma did not change with age, but UTIR levels were higher in the stomach cancer tissue than in the surrounding stomach mucosa. UTIR levels did not correlate with I alpha I levels in the plasma of patients with stomach cancer, thus the increase was not considered due to the contamination of circulating I alpha I in the cancer tissues.

Relationship between smoking and fibrinolytic system with special reference to t-PA and PA inhibitor

Recently tissue plasminogen activator (t-PA) has been clinically applied to the thrombolytic therapy of myocardial infarction. We investigated relationship between cigarette smoking and fibrinolytic system, namely the plasma level of t-PA antigen, plasminogen activator inhibitor (PAI), and PA activity. Nineteen healthy volunteers were asked to smoke for 10 min. The plasma levels of t-PA antigen, PAI activity, PA activity and catecholamine were measured together with measurement of blood pressure and heart rate before, soon after or 30 min after cigarette smoking. Plasma t-PA antigen after cigarette smoking increased to 8.83 +/- 3.11 ng per ml, significantly higher (p less than 0.005) than 6.35 +/- 1.7 ng/ml before cigarette smoking. Plasma PAI activity after cigarette smoking was 5.52 +/- 2.03 u/ml, significantly higher (p less than 0.05) than 4.18 +/- 1.06 u/ml before smoking. Plasma PA activity after smoking was 6.28 +/- 3.85 u/ml significantly higher (p less than 0.05) than 4. 49 +/- 2.74 u/ml. Furthermore, plasma epinephrine level after smoking increased to 59.1 +/- 52.4 pg/ml (p less than 0.1), compared with 36.2 +/- 22.5 pg/ml before smoking. There was a positive correlation between the rate of increase in plasma t-PA antigen and the rate of increase in plasma epinephrine after smoking. It is suggested that plasma epinephrine was related to the mechanism of increased plasma levels of t-PA in cigarette smoking.

Fibrinolytic activity in depression and neurosis

It has been a long-established clinical and epidemiological observation that patients with affective disorders have a higher than expected rate of mortality from cardiovascular disease (1,2). Further evidence suggests that major depression has a direct negative impact on the outcome of cardiovascular disease (3’1. The mechanism through which mental disorder is a cause of cardiovascular death in depressed patients and affects outcome in cardiac disease is far from clear. The fibrinolytic system plays a key role in defence against fibrin deposition on the vessel wall and is thus an essential protection against blood vessel occlusion. Decreased fibrinolytic activity is considered to be a factor involved in the pathogenesis of myocardial infarction, cerebral thrombosis and deep vein thrombosis. It seemed, therefore, of interest to evaluate the function of the fibrinolytic system in patients suffering from depression and neurosis using a newly developed assay for the determination of plasma plasminogen activators and inhibitors (4).

Determination of plasminogen activator inhibitor-1 (PAI-1) in plasma using two different anticoagulants and methods.

Platelets contain plasminogen activator inhibitor (PAI-1) in mainly inactive form which may be released during platelet activation. We wanted to compare effects of anticoagulant and time of blood storage on PAI-1 determination by two different methods