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Biomedical subjects

J Soria

Publications and source records attributed to J Soria.

At least 109 records · Page 6Linked to original sources
PubMed1990

Anesthesia and immunosuppression in an experimental model.

The purpose of the present work was to study: (1) if anesthesia induces changes in the helper/cytotoxic/suppressor T cell ratio in the rat spleen, and (2) if there is any difference between two anesthetic methods usually employed in rat experimentation. 50 Fisher 344 rats were allotted into 5 groups. In group A (control), a splenectomy was performed in an average time of 3 min under ether anesthesia. In groups B1 and B2, the rats anesthetized for 1 h with ether (group B1) or with one single dose of ketamine + atropine + diazepam (group B2) and then underwent splenectomy. Groups C1 and C2 were similar to groups B1 and B2 but splenectomy was performed 24 h later, under ether anesthesia during 3 min. T helper (Th) and T cytotoxic-suppressor (Ts-c) cells were identified in periarterial and follicular spleen tissue by means of an immunohistologic analysis using an immunoperoxidase technique with monoclonal antibodies. In periarterial tissue the Th/Ts-c ratio (mean +/- SE) was: group A, 1.61 +/- 0.11; group B1, 1.10 +/- 0.1; group B2, 1.28 +/- 0.11; group C1, 0.85 +/- 0.08, and group C2, 1.23 +/- 0.12. The differences between groups A and B1, C1 and C2 were statistically significant (t = 2.2833) as well as the difference between groups C1 and C2 (t = 2.5223). The Th/Ts-c ratio was also compared when equal to 1 or less than 1. The difference between groups A and C1 was statistically significant (p less than 0.05) as well. In follicular tissue the ratio was 1 in all the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1990

Absence of inhibition by lipoprotein (a) inhibition of tPA induced thrombolysis in a patient's plasma milieu.

The increase in Lp(a) is strongly correlated with premature coronary artery disease. The Apo(a) has striking homology to plasminogen. It was found in an in vitro purified system that Lp(a) competes with both plasminogen and tissue-type plasminogen activator (tPA) for fibrin binding sites, thus resulting in a decrease in fibrin-dependent plasminogen activation. In this study, plasma fibrinolysis was studied in a young patient who had a consistently high level of Lp(a) (198 mg/dl) and had suffered from cerebral thrombophlebitis 12 months previously. The patient had normal levels of plasma plasminogen and fibrinogen. The euglobulin lysis time before and after venous occlusion was not prolonged, and after the addition of tPA to the patient's plasma or whole blood, the clot lysis time was normal. The same result was obtained when the patient's plasma was depleted of Lp(a) before clotting. When the patient's plasma serpins were inhibited, plasminogen activation by tPA in the presence of several fibrin concentrations was normal, suggesting that the formation of the ternary complex tPA - plasminogen - fibrin was not inhibited by the presence of high levels of Lp(a). It is concluded that a consistently high level of Lp(a) in this patient did not inhibit tPA-dependent fibrinolysis, and the thrombotic episode was not therefore related to deficient thrombolysis.

Adult↗
PubMed1990

[Secretion of plasminogen activators and their inhibitors in corneal fibroblasts. Modification of this secretion in Schnyder's lens corneal dystrophy].

In this study, we have shown that the secretion of plasminogen activators (PA) by corneal fibroblasts from Schnyder dystrophy is much lower than that secreted by normal corneal fibroblasts. This defective secretion of PA was noted both in the supernatant of cell culture and on the cell surface. This anomaly is found in cultured fibroblasts and therefore is not related to environment modification. Since PA was implicated in remodeling of extracellular matrix, we hypothesized that this anomaly should be responsible for the corneal dystrophy.

Cells, Cultured↗
PubMed1989

Evaluation of the inhibition by heparin and hirudin of coagulation activation during r-tPA-induced thrombolysis.

Thrombin bound to a fibrin clot remains active and poorly accessible to heparin-AT III complex. During fibrinolysis, thrombin is released as thrombin-FDP complex and is inactivated by heparin-AT III. However, as successive fibrin layers are removed, inaccessible molecules of thrombin are exposed at the surface of the residual clot, possibly contributing to the occurrence during thrombolytic therapy of coagulation that is poorly controlled by heparin. We have investigated the accessibility of fibrin-bound thrombin to hirudin. The results clearly show that two recombinant hirudin variants neutralize thrombin both in solution and fibrin bound. Furthermore, we have found that in in vitro models, hirudin present in the surrounding medium of a clot under lysis is more efficient than heparin in preventing the activation of coagulation. This observation suggests that hirudin may be effective in the prevention of the rethrombotic process frequently encountered during thrombolytic therapy.

Adsorption↗
PubMed1989

Production of proteases type plasminogen activator and their inhibitor in cornea.

Corneal epithelial cells secrete tissue plasminogen activator (t-PA), urokinase type plasminogen activator (u-PA) and their inhibitor (PAI), whereas these cell types in other tissues are known to secrete only u-PA hitherto. Endothelial cells in the cornea produce mostly u-PA and only small amounts of t-PA and PAI which remain confined in the cellular compartment contrary to the situation in the vascular endothelial cells where they are liberated into the circulation in the order PAI greater than t-PA greater than U-PA. These unique features of activator/inhibitor secretion and production may play an important role in the remodeling of the corneal matrix.

Animals↗
PubMed1989

[The biology of fibrinogen. The role of pentoxifylline].

Recent epidemiological studies have shown that an increase in fibrinogen level (even a slight increase) is an important risk factor for vascular disease. Consequently, drugs which induce a decrease in fibrinogen are of great importance. Pentoxifylline given in patients with vascular disease or in those with high risk of thrombosis (diabetes, arteritis) induces a significant decrease in plasma fibrinogen level. Furthermore, in patients with arteritis, the decrease in fibrinogen level after pentoxifylline is correlated with the improvement in the walking distance. Several hypotheses may be taken into account to explain the decrease in fibrinogen induced by pentoxifylline. The hypothesis based upon a decrease of fibrinogen synthesis seems very fascinating since pentoxifylline, inducing a decrease in Interleukin 1 activity on leukocytes, might be responsible also for a decrease in interleukin 1 activity as fibrinogen stimulating factor. Furthermore, the effect of pentoxifylline on fibrinolysis, reported by some authors, is also of importance for the prevention of thrombotic disorder.

Fibrinogen↗
PubMed1989

[Fibrinogen and pentoxifylline. Results of a French cooperative exploratory study of stage II arteritis].

A collaborative exploratory study was undertaken by 139 private angiologists in 427 out-patients with PVD stage II treated for 90 days with Pentoxifylline 1 200 mg per day. In 306 patients (71,6%) the fibrinogen level was decreased by 0,21 g/l in mean (p less than 0.01). This significant decrease is correlated to the global improvement (p less than 0.01) and is within the magnitude of difference that is associated between vascular death and comparative groups in recent epidemiologic studies. In 121 patients (28, 4%) of the non responders in whom the claudication was not improved or was even worsened, no change in the fibrinogen level was seen.

Adult↗
PubMed1988

High frequency of plasminogen activator secretion by malignant human lymphoid cell lines of T-cell type origin.

Diffuse defibrination is rarely observed in acute lymphoblastic leukemia (ALL). Clinical and immunologic data suggest that it is more likely to occur in T cell derived ALL. The current investigation involved the secretion of plasminogen activators (PA) of tissue type (t-PA) or urokinase type (U-PA) by testing supernatants of 21 permanent human leukemic cell lines originating from various hematopoietic lineages and one induced lymphoblastoid cell line. (LCL) The amount of PA in each supernatant was determined by biologic and immunoenzymologic assays. The correspondence with the expected molecular weight (MW) according to the PA type was checked by zymography. PA secretion of U-PA type was observed in the three myeloid cell lines. Except for the normal LCL, no B-lymphoid lineage related cell lines of various levels of differentiation displayed PA secretion, whereas PA activity was observed in the supernatant of six of nine malignant T-cell lines. The T-leukemic cell lines CCRF CEM, KE 37, HUT 78, and HUT 102 released U-PA-like activity. Peer released t-PA-like activity and CCRF-HSB2 supernatant showed both types of PA activity. These findings are discussed in view of the natural history of these diseases and the stage of differentiation of the cell lines.

Humans↗
PubMed1988

New carbohydrate site in mutant antithrombin (7 Ile----Asn) with decreased heparin affinity.

A mutant antithrombin was isolated from the plasma of a patient with pulmonary embolism. The new protein, which accounted for 55% of the antithrombin, had decreased heparin affinity and contained two components when analysed on the basis of either charge or molecular mass. Sialidase and endo-beta-N-acetylglucosaminidase F treatment suggested that this heterogeneity was due to a partial glycosylation occurring at a new carbohydrate attachment sequence. Peptide mapping by reverse-phase HPLC showed that the abnormality involved the N-terminal tryptic peptide. Sequence analysis demonstrated that the underlying mutation was 7 Ile----Asn which introduces a new Asn-Cys-Thr glycosylation sequence. This new oligosaccharide attachment site occupies the base of the proposed heparin-binding site, and the finding explains the consequent decrease in heparin affinity.

Antithrombin III↗
PubMed1988

Parallel induction of fibrinolysis and receptors for plasminogen and urokinase by interferon gamma on U937 cells.

A new cell sorter technique was employed to study the role of interferon gamma (INF gamma) in fibrinolysis induced by U937 monocytic cells. INF-gamma induced the differentiation of U937 cells as evidenced by the appearance of CD 14 antigen on the cell surface. Scatchard analysis and dose response curves showed a parallel increase in the number of receptors on U937 cells capable of accepting exogenous plasminogen and urokinase (UPA) synthetized by differentiating U937 monocytic cells. This would favour an activation of plasminogen by UPA. This adds a new parameter in the regulation of cell-mediated fibrinolysis and may be important in a number of biological processes.

Cell Line↗
PubMed1988

Effect of lupus anticoagulant on antithrombogenic properties of endothelial cells--inhibition of thrombomodulin-dependent protein C activation.

We have investigated the effect of purified immunoglobulin G (IgG) on endothelial cell functions in 16 patients with lupus anticoagulant, 9 of whom had systemic lupus erythematosus (SLE). Spontaneous or thrombin-stimulated secretion of prostacyclin (PGI2) by cultured human endothelial cells from umbilical cord vein (HUVEC) was not inhibited by the patient's IgG. Nor was spontaneous release of tissue plasminogen activator (t-PA) or of its inhibitor (PAI) modified in the presence of patient's IgG. The rate of activation of purified protein C (PC) by HUVEC in the presence of thrombin was significantly lowered by patient's IgG or Fab' fragment (inhibition of 43%). Neutralization of this effect was obtained by incubation of a greater quantity of phospholipids (phosphatidylcholine, phosphatidylserine) with the patient's IgG. Activation of PC was also performed using purified rabbit thrombomodulin (TM) and a similar inhibition of the patient IgG was observed (inhibition of 48%) but the activation of Gla-domainless PC was not modified.

Animals↗
PubMed1988

Changes in plasma fibrin degradation products as a marker of thrombus evolution in patients with deep vein thrombosis.

The level of fibrin degradation products (fdp) as a marker of fibrin clot dissolution was studied prospectively in 51 patients with phlebographically identified deep vein thrombosis (DVT). For this purpose a highly sensitive fdp assay using an anti D neo monoclonal antibody (McAb) was used. At the onset of the hospitalization, in 47 (92%) of the 51 patients tested, the plasma fdp level performed was high, but does not reflect the size of the thrombus, demonstrating that spontaneous thrombus lysis varies from one patient to another. During 10 days of standard heparin or low molecular weight heparin treatment, two different patterns of fdp evolution could be identified in these patients, independent of the type of heparin used. The first was characterized by a gradual decrease in fdp level and a corresponding reduction in the thrombus size. The second pattern showed a persistence of high levels of fdp after 10 days of therapy although the phlebographic score reveals a poor or partial response indicating that fibrinolysis or the balance of thrombus formation/fibrinolysis did not insure total thrombus dissolution. The 4 patients whose initial plasma fdp levels were only slightly increased during the 10 days, seem to have poor thrombolysis, as was shown by the unmodified phlebographic score after 10 days of treatment. Consequently, we conclude that the investigation of plasma fdp levels with a highly sensitive assay should contribute to the evaluation of thrombus evolution in DVT.

Enzyme-Linked Immunosorbent Assay↗
PubMed1988

Enhanced expression of urokinase activity on U 937 cell line by 1,25-dihydroxyvitamin D3 induction.

1,25 Dihydroxyvitamin D3 is a differentiation inducer for monocytic cell. It can induce a monoblastic cell line U937 to differentiate. In this paper, we report that by inducing the differentiation of U937, 1,25-dihydroxyvitamin D3 increased urokinase activity expression on U937 cell surfaces. After incubation of the cell with various concentrations of 1,25-dihydroxyvitamin D3, the cell line showed a remarkable progressively increasing membrane-associated urokinase activity in a dose dependent manner. On the contrary, plasminogen activator inhibitor activity which was found in the culture medium is not modified by the 1,25-dihydroxyvitamin D3 induction. This results suggests another role of 1,25-hydroxyvitamin D3 in the treatment of myelofibrosis, since enhanced plasmin generation can accelerate the activation of procollagenase. The induced plasmin and collagenase activities surrounding the monocytic cells may participate in the physiological and pathological events, especially in the connective tissue degradation.

Calcitriol↗