No abstract

Although a considerable number of publications on tissue plasminogen activator (t-PA) in human milk have appeared, most investigators have determined t-PA activity using an assay on fibrin plates [1, 2, 3, 4]. We measured t-PA activity by a bioimmunoassay and t-PA antigen by ELISA using a monoclonal antibody (SP-322) [6], and estimated t-PA index ((t-PA activity, ng/ml)/(t-PA antigen, ng/ml) x 100) in human colostrum and milk to evaluate the fluctuations of post-delivery t-PA. The concentrations of t-PA activity decreased slowly related to the duration of lactation varying between days one and two hundred and ten and showed significant negative correlation with the duration (P less than 0.001). The t-PA antigen made a slow descent, followed by a reciprocal ascent of the t-PA index to the fifty eighth post-delivery day and showed significant correlations with the duration (P less than 0.001, P less than 0.05, respectively). This information suggests that a high concentration of t-PA may be released into the narrow channels of the glands functioning to maintain duct patency under the regulation of an inhibitor such as plasminogen activator inhibitor (PAI).

Concentrations of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) were measured in blood obtained from pregnant women to elucidate the fluctuations in the fibrinolytic system which occur during the course of pregnancy. The t-PA activity was measured with a modified bioimmunoassay using anti-t-PA monoclonal antibody (SP-322) against a single chain of recombinant t-PA. The t-PA antigen was measured by ELISA using the same antibody. PAI activity was determined with a competitive inhibition assay of t-PA activity. In early pregnancy, t-PA activity was found to be close to the standard range seen in nonpregnant women, and gradually decreased during the course of pregnancy, then recovered to rise to the normal range within 48 hours after delivery. The t-PA antigen and PAI activity levels rose slowly during the course of pregnancy, and fell promptly after delivery. t-PA activity and t-PA antigen in levels in umbilical cord blood were higher after vaginal delivery than after cesarean section. These findings suggest that there may be an important physiological balance of the fibrinolytic system between mother and fetus during the course of pregnancy and the puerperium.

The statistical association between tissue plasminogen activator (t-PA) activity, antigen, plasminogen activator inhibitor-1 (PAI-1) antigen and lipids levels in blood samples used for medical check ups in 111 volunteers attending hospital for health examinations was examined. The t-PA activity level of 111 volunteers was 0.08-0.56 ng/ml (5% trimmed range) (normal range: 0.08-0.70 ng/ml); t-PA antigen concentrations were 2.4-9.2 ng/ml (normal range: 1.0-7.0 ng/ml); PAI-1 antigen concentrations were 5.2-57.4 ng/ml (normal range: 5.2-45.0 ng/ml). The volunteers with the lowest t-PA activity in blood (group E) had higher concentrations of serum total cholesterol (P less than 0.001), triglycerides (P less than 0.001), or t-PA antigen (P less than 0.001) and lower concentrations of high-density lipoprotein cholesterol (P less than 0.001) than those having normal serum lipids and t-PA activity level (group A). These results show that t-PA activity, antigen and PAI-1 antigen in blood obtained from the healthy volunteers are influenced significantly by the concentrations of lipids in blood.

In order to obtain information useful for the diagnosis of fetus and newborn heart disease, we established a theoretical model of perinatal cardiac growth. We measured with the use of ultrasonic cross-section imaging system the mitral valve ring dimension, tricuspid valve ring dimension, and total cardiac dimension as morphological parameters of the heart in 45 cases composed of fetuses and children. The obtained data were entered into a computer. With the use of these data, simulation was made on the basis of the general theory of biological development. The present simulation showed that from the fetal stage to childhood the growth rates of the foregoing three morphological parameters mutually differ, but during the period of growth to the age of 12 years of the present study, they all demonstrated continuous growth up to 3 1/2 years after birth when they reached a growth saturation level.