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Biomedical subjects

B Astedt

Publications and source records attributed to B Astedt.

At least 19 recordsLinked to original sources
PubMed1992

Peaks in plasma plasminogen activator inhibitor-1 concentration may explain thrombotic events in cases of pancreatic carcinoma.

Pancreatic carcinoma is associated with a high frequency of thrombosis. Most patients with thrombotic disease have a defective fibrinolytic defense system caused either by plasminogen activator deficiency, excess of plasminogen activator inhibitor (PAI-1), or a combination of the two. In the current series of 27 patients with pancreatic carcinoma, 17 had had deep vein thrombosis (DVT) since the onset of their malignant disease, and most were found to have high plasma concentrations of PAI-1 antigen and PAI-1 activity. Analysis of singleton samples from each patient yielded no correlation between previous DVT and currently high plasma PAI-1 concentrations. However, serial samples from 14 patients (8 of whom had histories of thrombosis) showed individual values varied sharply with time, with intermittent peaks both in PAI-1 antigen and PAI-1 activity for 11 of the 14 patients. Such variability may contribute to intermittently excessive hypercoagulability because of a relative reduction in fibrinolytic potential. These changes may predispose the patient to have thrombotic events in association with pancreatic carcinoma.

Humans↗
PubMed1992

Prospective histopathologic malignancy grading to indicate the degree of postoperative treatment in early cervical carcinomas.

During a 9-year period, 92 women with squamous cell carcinoma of the cervix, FIGO stages IA1-IIA, were subjected to primary surgery according to Wertheim Meigs. Grading according to a malignancy grading score (MGS) and evaluation of tumor size before surgery together with surgical findings of positive nodes or insufficient surgical margin at the primary site were used to identify persons prospectively at high risk for relapse. Twenty-five women thus received postoperative treatment. Results among node-positive patients were good; only 2 out of 12 patients relapsed. Among 67 node-negative patients in stages IA2-IIA, 4 relapses occurred. These 4 patients had greater than or equal to 16 risk points according to MGS, but small tumors. Instead of tumor size, supplementary risk factor is therefore needed. Among the few patients in stage IA1, no high-point patients relapsed. These patients would probably have done just as well with less-extensive surgery.

Adult↗
PubMed1992

Surgical treatment versus thrombolysis in acute arterial occlusion: a randomised controlled study.

Thrombolytic treatment has been tried in various forms for acute limb ischaemia with varying degrees of success but is also often accompanied by bleeding problems. The present investigation compares the effect of surgical thrombectomy (TE) and thrombolysis (TL) using recombinant tissue plasminogen activator (rt-PA). Twenty patients with a need for intervention owing to ischaemia lasting more than 24 h but less than 14 days were included. Patients randomised to TE were operated under epidural anaesthesia and patients in the TL group received 30 mg rt-PA during a 3 h period through a catheter placed into the thrombus and advanced as lysis was achieved. Thrombectomy resulted in an immediate restitution of blood flow in six out of nine cases, in three cases a bypass procedure was performed, and one of these failed with a resultant amputation. Thrombolysis gave a good primary result in six cases which lasted in four of them. Three had a subsequent percutaneous transluminal angioplasty. Partial lysis was seen in two cases and a further two failed. Five went to surgery with three bypass and two fogarty procedures being necessary. There was no hospital mortality and there were no bleeding complications due to the rt-PA treatment in this series. In 19 out of 20 patients the circulation was re-established. Appropriate handling of acute ischaemic conditions implies the use of both thrombolysis and appropriate surgical procedures, including distal bypass grafts.

Acute Disease↗
PubMed1991

Identity between the placental protein PP10 and the specific plasminogen activator inhibitor of placental type PAI-2.

The highly specific plasminogen activator inhibitor of placental type, PAI-2, occurs in the placenta in a low molecular mass form of 46.6 kDa, and in pregnancy plasma in a (possibly glycosylated) high molecular mass form of 60 kDa. Extensive knowledge is available about the functional properties of PAI-2 as a plasminogen activator inhibitor and about its molecular biology and regulation. Of the several placenta proteins (PP) isolated, one of them, PP10, has a molecular mass of 48 kDa and its occurrence in malignancy and in complications during pregnancy has been the topic of a number of studies, though its properties and physiological significance are unknown. The present findings constitute evidence of immunological identity between PP10 and PAI-2. The sections of the amino acid sequence of PP10 analysed here were found to have identical counterparts in the sequence of the low molecular mass form of PA1-2, but in several preparations PP10 was found to occur in an inactive two-chain form due to cleavage of an Arg-Thr bond, the two peptide chains being linked to each other by a disulphide bridge. The cleavage site is identical to that observed in the reaction between PAI-2 and urokinase. The results make it possible to coordinate and correlate the findings of many separate studies and our own observations on PP10 and PAI-2.

Amino Acid Sequence↗
PubMed1991

Cell membrane receptors for urokinase plasminogen activator are increased in malignant ovarian tumours.

The binding of 125I-labelled urokinase plasminogen activator (uPA) to cell membranes of ovarian tumours was characterised. Binding was fast, specific to HMW-uPA, and saturated at low concentration [1.5 (range 1.2-1.6) nmol/l]. Scatchard analysis suggested a single class of binding sites with Kd 1.1 (0.9-1.3) nmol/l. These data indicate the presence of a specific cell membrane receptor for uPA in ovarian tumours, whose characteristics are similar to those reported for uPA receptors in other tissues. Endogenously occupied receptors were uncovered by exposing the membranes to acid conditions (pH 2) before assay, thereby allowing quantitation of the total amount of receptor. uPA receptors were assayed in 10 malignant and 6 benign epithelial ovarian tumours. The total number of receptors was higher in the malignant tumours. This was secondary to increases of both free and occupied receptors. We conclude that this reflects the biological function of cell surface bound plasminogen activation in tumour growth and spread.

Adenocarcinoma↗
PubMed1990

Depressed bronchoalveolar urokinase activity in patients with adult respiratory distress syndrome.

Abundant deposition of bronchoalveolar fibrin and fibronectin occurs during the exudative phase of the adult respiratory distress syndrome (ARDS), promoting hyaline-membrane formation and subsequent alveolar fibrosis. To explore the mechanisms that account for the persistence of bronchoalveolar fibrin and fibronectin, we compared the activity of urokinase, which is necessary for plasminogen activation and fibrin degradation, in cell-free bronchoalveolar-lavage fluid from 8 patients with ARDS, 9 patients with acute pulmonary diseases other than ARDS, and 10 normal subjects. The mean level of urokinase activity in the lavage fluid from the patients with ARDS was 0.003 IU per milliliter of fluid (range, 0 to 0.008), which was significantly lower (P = 0.001) than the level in the fluid from either the patients with pulmonary diseases other than ARDS (0.118 IU per milliliter [range, 0.032 to 0.295]) or the normal subjects (0.129 IU per milliliter [range, 0.045 to 0.198]). The lavage fluid from all the patients with ARDS also had antiplasmin activity, which would promote the persistence of fibrin. A true decrease in urokinase activity was confirmed by the failure of the lavage fluid from the patients with ARDS to convert [125I]plasminogen to plasmin. Despite the low urokinase activity, immunochemical assays revealed normal levels of urokinase antigen in the fluid from the patients with ARDS, suggesting the presence of urokinase inhibitors. Inhibitors were demonstrated directly by a fibrin gel-underlay assay that detects complexes of urokinase with inhibitors. Plasminogen-activator inhibitor type 1 was the principal inhibitor identified. We conclude that increased antifibrinolytic activity due to both urokinase inhibitors and antiplasmins in the bronchoalveolar compartment of patients with ARDS contributes to the formation and persistence of hyaline membranes, a key component of alveolar histopathology in ARDS.

Adult↗
PubMed1990

Acute massive pulmonary embolism treated with streptokinase during labor and the early puerperium.

Acute massive pulmonary embolism occluding 60-70% of the pulmonary circulation occurred in a young primipara during the 28th week of pregnancy. She was critically ill despite 40 h of heparin infusion and thrombolytic therapy with streptokinase was initiated. After a 10-h infusion she went into labor and streptokinase treatment was stopped. One hour later she gave birth spontaneously to a preterm infant in footling breech delivery. The infant did well neonatally. Streptokinase infusion was recommenced 8 h after delivery. Because of increasing blood loss on the second day after delivery, streptokinase was withdrawn after a total treatment time of 29 h. Total hemorrhage amounted to 8.9 litres. Serial perfusion lung scans showed complete resolution of the emboli and normal lung function was restored.

Acute Disease↗
PubMed1990

[Thrombotic and hemostatic problems in pregnancy and labor and their significance for the fetus and newborn infant].

The following problems are considered: Thrombosis: Safe diagnosis with phlebographic verification is recommended. Heparin has been an established treatment with the great advantage that it does not enter the fetal blood stream. In selected cases surgery or thrombolytic therapy has to be considered. Owing to the high risk of recurrence, prophylactic treatment with Heparin is required throughout pregnancy. Coumarol derivatives traverse the placental membrane to the foetus and have to be avoided because of a risk for teratogenetic injury and intracranial hemorrhage in the foetus. During the puerperium, warfarin might be given because its concentration in breastmilk is low. However, administration of vitamin K1 is recommended to prematures. Attention should be given to the side-effects of Heparin i.e. thrombocytopenia and osteoporosis. The possibility of antithrombin III deficiency should not be overlooked. In such cases it is also risk of thrombosis in the newborn. Premature separation of placenta: In most cases of abruptio placenta immediate delivery by caesarean section is necessary. In cases with partial separation of placenta and immature foetus, treatment with the fibrinolytic inhibitor tranexamic acid (Cyklokapron) has proved useful to prolong pregnancy with maturation of the foetus. Thrombocytopenia: Severe hemorrhage seldom occurs above a level of 50 x 10(9)/l. Treatment with Prednisolon has proved to be of great value. The risk of the child having thrombocytopenia is about 50%. Intraventricular bleedings: Such bleedings mainly occur in prematures. Preliminary results have shown decreased concentrations of specific plasminogen activator inhibitors.

Abnormalities, Drug-Induced↗
PubMed1990

Ultrasound examination for detection of ovarian carcinoma in risk groups.

Ovarian ultrasound scanning was carried out as an adjunct to pelvic examination in 801 women between 40-70 years of age presenting at the outpatient Department of Obstetrics and Gynecology, University Hospital, Lund, Sweden for a variety of gynecologic complaints. All belonged to a high-risk category for ovarian carcinoma because of nulliparity; family history of ovarian, breast, or endometrial carcinoma; previous cancer; or unspecified abdominal complaints. Of 638 patients with normal scans, findings at pelvic examination had been abnormal in 51 cases, and all were normal at subsequent clinical follow-up. Among 163 patients with abnormal ultrasound scans, one case of borderline ovarian tumor and two cases of endometrial cancer were found for which the pelvic examination had been considered normal. Clinical symptoms probably would have led to detection within a short time in these cases anyway, even if ultrasound had not been performed. Based on the findings in this study and the previous experience with gynecologic ultrasound in several thousand patients, it would not seem that ultrasound has a role in screening for ovarian carcinoma.

Adult↗
PubMed1989

Urokinase binds to a plasminogen activator inhibitor type-2-like molecule in placental microvillous membranes.

Placental microvillous membranes exhibited saturable binding of urokinase-type plasminogen activator with plateau achieved by 30 min at 4 degrees C and 10 min at 37 degrees C. The binding was essentially irreversible. The capacity was about 8 pmol urokinase per mg membrane protein. Half-maximal displacement of 125I-labelled urokinase was achieved with about 1.0 nM unlabelled urokinase when using 75 micrograms membrane protein/ml. 125I-labelled urokinase did not bind when treated with diisopropylfluorophosphate to block the catalytic activity. Single-chain urokinase (prourokinase), devoid of catalytic activity, did not bind. Catalytically active tissue-type plasminogen activator did compete with 125I-labelled urokinase for binding although less efficiently than urokinase. Binding activity remained in the 100,000 x g pellet after treatment of the membranes with 3 M KCl, alkaline stripping at pH 12 or extraction by the detergent Triton X-100. The binding was essentially blocked by antibodies against plasminogen activator inhibitor-type-2 (PAI-2). Sodium dodecyl sulfate polyacrylamide gel electrophoresis of solubilized membranes with bound 125I-labelled urokinase showed that the urokinase-PAI-2 complexes largely migrated in fractions corresponding to a very large Mr although no clearly defined peaks were observed. It is suggested that PAI-2 occurs in a form anchored to syncytiotrophoblast microvilli, possibly to the cytoskeleton.

Chorionic Villi↗
PubMed1989

Placental and decidual u-PA, t-PA, PAI-1 and PAI-2 concentrations, as affected by cervical dilatation with laminaria tents or Hegar dilators.

The effect of cervical dilatation on PA and PAI concentrations was compared in a laminaria tent group and a mechanical dilatation (control) group. In both groups, u-PA and t-PA were found to be present both in decidual and placental tissue. Values for PAI-1 in the decidua were higher in the laminaria tent group than in controls, and those for PAI-2 in the placenta were lower. These findings provide support for the contention that cervical dilatation with laminaria tents may result in partial detachment of the placenta.

Decidua↗
PubMed1989

Human fetal dopamine neurons grafted into the striatum in two patients with severe Parkinson's disease. A detailed account of methodology and a 6-month follow-up.

By using stereotaxic surgical techniques, ventral mesencephalic tissues from aborted human fetuses of 8 to 10 weeks' gestational age were implanted unilaterally into the striata in two patients with advanced Parkinson's disease. The patients were treated with a cyclosporine, azathioprine, and steroid regimen to minimize the risk for graft rejection. They were examined for 6 months preoperatively and 6 months postoperatively and continued to receive the same doses of antiparkinsonian medication. There were no significant postoperative complications. No major therapeutic effect from the operation was observed. However, in the clinical tests, both patients showed small but significant increases of movement speed for repeated pronation-supination, fist clenching, and foot lifting. The rate of walking also increased in the one patient tested. For both patients, there was an initial worsening postoperatively, followed by improvement vs preoperative performance at 1 to 3 months. Both patients also showed significant improvement in the magnitude of response to a single dose of levodopa (L-dopa), but there was no increase in the duration of drug action. The motor readiness potential increased in both patients postoperatively, primarily over the operated hemisphere. Neurophysiological measurements also showed a more rapid performance of simple and complex arm and hand movements on the side contralateral to transplantation in one patient at 5 months postoperatively. Positron emission tomography demonstrated no increased uptake of 6-L-(18F)-fluorodopa in the transplanted striatum at 5 and 6 months. Taken together, these results suggest that the fetal nigral implants may have provided a modest improvement in motor function, consistent with the presence of small surviving grafts. Although our results support further scientific experimentation with transplantation in Parkinson's disease, widespread clinical trials with this procedure are probably not warranted at this time.

Contingent Negative Variation↗
PubMed1989

The effect of cervical dilatation by laminaria tent in first trimester legal abortions on blood loss related to fibrinolytic activity in the decidua and placenta.

Increased blood loss (BL) has been reported after cervical dilatation by laminaria tent in legal abortions. The BL was measured in 72 women in whom first trimester legal vacuum aspiration was performed. The cervical canal was dilatated by laminaria tent in 37 patients, and mechanically with Hegar dilators in 35 patients. BL was studied in relation to the plasminogen activators (u-PA, t-PA) and the plasminogen activator inhibitors (PAI-1, PAI-2) in the decidua and placenta. There was no significant difference in BL between the two groups. Decidual PAI-1 concentrations were significantly higher in the laminaria tent group than in the Hegar dilator group. An inactivation of u-PA by PAI-1 might explain the lack of increase in BL among the laminaria tent group.

Abortion, Induced↗
PubMed1989

Repeated cranial computed tomographic and magnetic resonance imaging scans in two cases of eclampsia.

In two cases of eclampsia with consumptive thrombocytopenia, the maximum increase in blood pressure and the lowest platelet count coincided with the maximum degree of neurologic and neuroradiologic abnormality. Computed tomograms showed decreased attenuation, and T2-weighted magnetic resonance images showed increased signal intensity focally in the cerebral cortex and the deep gray and white matter. Blood pressure, platelet count, clinical status, and roentgenograms normalized completely in both cases. Severe arterial hypertension and disseminated transitory microvascular occlusions presumably caused multiple small foci of brain edema that resolved without remaining detectable ischemic brain damage.

Adult↗
PubMed1988

Kinetics of inhibition of tissue-type and urokinase-type plasminogen activator by plasminogen-activator inhibitor type 1 and type 2.

Highly purified plasminogen-activator inhibitors of type 1 (PAI-1) and type 2 (PAI-2), low-Mr form, were compared with respect to their kinetics of inhibition of tissue-type (t-PA) and urokinase-type plasminogen activator (u-PA). The time course of inhibition of plasminogen activator was studied under second-order or pseudo-first-order conditions. Residual enzyme activity was measured by the initial rate of hydrolysis of a chromogenic t-PA or u-PA substrate or by an immunosorbent assay for t-PA activity. PAI-1 rapidly reacted with single-chain t-PA as well as with two-chain forms of t-PA and u-PA. The second-order rate constant k for inhibition of single-chain t-PA (5.5 x 10(6) M-1 s-1) was about three times lower than k for inhibition of the two-chain activators. PAI-2 reacted slowly with single-chain t-PA, k = 4.6 x 10(3) M-1 s-1. The association rate was 26 times higher with two-chain t-PA and 435 times higher with two-chain u-PA. The k values for inhibition of single-chain t-PA, two-chain t-PA and two-chain u-PA were respectively, 1200, 150 and 8.5 times higher with PAI-1 than with PAI-2. The removal of the epidermal growth factor domain and the kringle domain from two-chain u-PA did not affect the kinetics of inhibition of the enzyme, suggesting that the C-terminal proteinase part of u-PA (B chain) is responsible for both the primary and the secondary interactions with PAI-1 and PAI-2. The k values for inhibition of single-chain t-PA and endogenous t-PA in plasma by PAI-1 or PAI-2 were identical indicating that t-PA in blood consists mainly in its single-chain form.

Glycoproteins↗
PubMed1988

Epidermal plasminogen activator inhibitor (PAI) is immunologically identical to placental-type PAI-2.

Plasminogen activator inhibitor (PAI) purified from human epidermis [(1986) FEBS Lett. 408, 273-277] was immunologically identified as placental-type PAI-2. In both fibrinolytic and synthetic substrate assays inhibitory activity of epidermal PAI was neutralized by anti-PAI-2, but not by anti-endothelial type PAI-1. Immunoblotting technique confirmed that the purified epidermal PAI is reactive with anti-PAI-2, but not with anti-PAI-1. Consequently PAI in human epidermis was demonstrable by immunohistochemical technique.

Antibodies, Monoclonal↗