To elucidate which component(s) of thei fibrinolytic system is (are) responsible for the diurnal variation of fibrinolytic activity we have studied several parameters of this system in 8 healthy male volunteers during a period of. 24 h. Blood was collected at 8 a. m., 10 a. m., 12 a. m., 4 p.m., 8 p.m. and 8 a. m. next morning. The following tests were performed: euglobulin clot lysis time (ECLT), fibrinolytic activity of euglobulins on fibrin plates in the presence and absence of blocking antibodies to tissue-type plasminogen activator (t-PA) and/or urokinase (u-PA), overall plasminogen activator inhibitor (PAI) activity, antigen levels of t-PA, u-PA and PAI-I and zymography of the euglobulin fraction after SDS-PAGE. From 8-10 a. m. to 4-8 p. m., total fibrinolytic activity increased by 1l3% (p <0.01) or 71%h (p <0.01) when measured by ECIX or by fibrin plate assay, respectively. The immunoquenching experiments showed that this increase was entirely due to t-PA related activity whereas u-PA activity and t-PA/u-PA independent activity remained constant during the day. Average antigen levels of u-PA and t-PA in the afternoon were 6% and 25% lower than those measured in the morning. During this period, overall PAI activity and PAI-1 antigen decreased by 3l% (p <0.01) and 52% (p <0.01) respectively. Electrophoretic-zymographic analysis of_ the euglobulins revealed that throughout the day the majority of t-PA was present in the form of the 110 kDa t-PA/PAI-I complex. The intensity of this cornplex was lowest in the afternoon. Free t-PA was almost undetectable in morning samples, but constituted a significant proportion of total t-PA in the afternoon. The diurnal increase of fibrinolytic activity, therefore, is not due to an augmentation of antigen levels of t-PA and/or u-PA but to a decline of those of PAI-1.

During pregnancy the plasma concentration of two different inhibitors of plasminogen activators (PAIs) increases. The only one found in the plasma of nonpregnant women (PAI1) is immunologically related to a PAI of endothelial cells; its plasma activity, as deduced from the inhibition of single-chain tissue-type plasminogen activator (t-PA), increased from 3.4 +/- 2.3 U/mL (mean +/- 95% confidence limits) in the plasma of nonpregnant women to 29 +/- 7 U/mL at term, and its antigen level, measured by a radioimmunoassay, increased from 54 +/- 17 ng/mL to 144 +/- 25 ng/mL. In pregnancy plasma a second PAI (PAI 2) related to a PAI found in placenta extracts was observed. Its level, quantified with a radioimmunoassay, increased from below the detection limit (approximately 10 ng/mL) in normal plasma to 260 ng/mL at term. One hour after delivery, PAI 1 activities and antigen decreased sharply, but the PAI 2 antigen levels remained constant. Three days later, the PAI 1 antigen levels had fallen to normal levels, but the PAI 2 antigen levels were still at least eightfold above the nonpregnant values. During pregnancy, the t-PA and prourokinase (u-PA) antigen concentrations increased 50% and 200%, respectively, whereas the plasminogen and alpha 2-antiplasmin levels remained constant. Despite the large variations in the levels of PAs and PAIs, the overall fibrinolytic activity as measured in diluted plasma by a radioiodinated fibrin plate assay did not change significantly. Just after delivery, a great increase in the t-PA antigen levels was observed. Three to five days after delivery most parameters of the fibrinolytic system were normal again. Our results demonstrate that during pregnancy and in the puerperium profound alterations of the fibrinolytic system occur that are characterized by increases in PAs and their inhibitors, but these alterations do not affect the overall fibrinolytic activity.

weeks plasma total thyroxine and thyroid stimulating hormone concentrations were normal. He had no diarrhoea or allergic symptoms and was more active and lively. Iodine supplements were stopped. After eight weeks his response to thyrotrophin releasing hormone was normal. He had gained 1 5 kg in weight and 2 0 cm in height.

L-selectin is expressed by most leukocytes and mediates the initial step of adhesion to vascular endothelium. A feature of this adhesion receptor is to be shed from the cell surface. We report here the presence of high levels of the shed form of L-selectin (sL-selectin) in plasma from patients with acute leukemia. We also show that sL-selectin purified from acute leukemia plasma exhibits functional activity. The mean (+/- 1 SD) plasma level of sL-selectin among 100 healthy individuals was 2.1 +/- 0.7 micrograms/mL. This value was increased (> 2 SD above the mean) in 63% of 58 patients with acute lymphoblastic leukemia (ALL) and 59% of 93 patients with acute myelogenous leukemia ([AML] P < .001). Repeated measurements in 24 patients showed normal- range levels in 16 of 16 patients in complete remission and high levels in eight of eight patients with therapy-resistant acute leukemia or leukemia relapse. Furthermore, elevated sL-selectin levels were detected in cerebrospinal fluid of three patients with ALL suffering from a relapse limited to the central nervous system. Epitope mapping with monoclonal antibodies demonstrated that L-selectin shedding from leukemic blasts was accompanied by conformational changes of its epidermal growth factor-like domain. A functional role for sL-selectin purified from leukemic plasma was supported by its ability to completely inhibit L-selectin-dependent adhesion of blast cells to tumor necrosis factor-alpha (TNF-alpha)-activated endothelium in vitro. These results suggest that sL-selectin may have an important role in the regulation of leukemic cell adhesion to endothelium. In addition, monitoring of the sL-selectin level may be useful for evaluating leukemia activity, in particular for the detection of leukemia relapse.

To better characterize the plasminogen activators present in the euglobulin fraction (EF) of plasma before and after venous occlusion, euglobulins of 30 healthy volunteers and of 32 patients with idiopathic thromboembolic disease were submitted to SDS-PAGE and zymographic detection. The patterns thus obtained were compared to the fibrinolytic activity (FA) of the EFs measured on fibrin plates. There were significantly more patients with a low fibrinolytic response (FR) to stasis (difference between FA after and before stasis less than or equal to 0.3 TAU/ml) than controls (P less than 0.01). The electrophoretic-zymographic analysis revealed that: (i) in the resting state vascular plasminogen activator (v-PA) is always present in a form exhibiting a mol wt of 110 000 (complex of v-PA with its fast-acting antiactivator); (ii) a high FR to stasis (greater than 1.3 TAU/ml) is always associated with the presence of free v-PA (68 kdalton band); (iii) free v-PA is never detected when the FR is low; and (iv) a poor FR is generally (15 of 17 patients with low FR) associated with apparently complete inhibition of the released v-PA by the fast-acting antiactivator; in the two remaining patients in whom no broadening of the 110 kdalton band is observed, the release mechanism for v-PA is probably impaired.