Influence of SIN-1 on Platelet Ca2+ Handling in Patients with Suspected Coronary Artery Disease: Ex Vivo and In Vitro Studies

2000 ◽  
Vol 83 (05) ◽  
pp. 752-758 ◽  
Author(s):  
Claude Le Feuvre ◽  
Annie Brunet ◽  
Thuc Do Pham ◽  
Jean-Philippe Metzger ◽  
André Vacheron ◽  
...  
Keyword(s):  
Superoxide Anion ◽  
Vascular Tone ◽  
Ex Vivo ◽  
Suspected Coronary Artery Disease ◽  
In Vitro Studies ◽  
H2o2 Formation ◽  
Artery Disease ◽  
Dose Dependent

SummaryThe 3-morpholinosydnonimine (SIN-1) generates both nitric oxide (NO) and superoxide anion (O2−). It elicits dose-dependent vasodilation in vivo, in spite of the opposite effects of its breakdown products on vascular tone and platelet aggregation.This study was designed to investigate the influence of intravenous SIN-1 injection on platelet Ca2+ handling in patients undergoing coronary angiography. SIN-1 administration reduced cytosolic [Ca2+] in unstimulated platelets by decreasing Ca2+ influx. It attenuated Ca2+ mobilization from internal stores evoked by thrombin or thapsigargin. In vitro studies were used as an approach to investigate how simultaneous productions of NO and O2− from SIN-1 modify thrombin- or thapsigargin-induced platelet Ca2+ mobilization. Superoxide dismutase, the O2− scavenger, enhanced the capacity of SIN-1 to inhibit Ca2+ mobilization but catalase had no effect.This suggests that the effects of SIN-1 on platelet Ca2+ handling resemble those of NO, but are modulated by simultaneous O2− release, independently of H2O2 formation.

scholarly journals Four ricin chain A-based immunotoxins directed against the common chronic lymphocytic leukemia antigen: in vitro characterization

Blood ◽  
1993 ◽  
Vol 82 (2) ◽  
pp. 536-543
Author(s):  
GB Faguet ◽  
JF Agee
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
T Lymphocytes ◽  
Ex Vivo ◽  
Lymphocytic Leukemia ◽  
Fab Fragment ◽  
In Vitro Characterization ◽  
The Common ◽  
Dose Dependent

The common B-chronic lymphocytic leukemia (B-CLL) antigen (cCLLa) appears to be ideal for targeted immunotherapy in that it is the most prevalent and disease-restricted marker in B-CLL. To assess this potential, we developed four immunotoxins (ITs) of anti-cCLLa monoclonal antibody CLL2m (an IgG2a kappa), using ricin chain A (RTA) or its deglycosylated derivative (dgA), each conjugated to either the whole IgG molecule or its Fab' fragment. Each IT was tested in vitro for specificity and cytotoxic activity (assessed by protein synthesis inhibition [PSI] and by cell kill [CK] in the clonogenic assay) against B-CLL cells. RTA-based anti-CD5 ITs and enriched normal B and T lymphocytes were used as controls. Each IT exhibited antigen-specific, dose-dependent activity. Thus, whereas B-CLL cells exhibited dose- dependent PSI and CK (whether the B-CLL clone was CD5+ or CD5-), normal B (cCLLa-/CD5-) and T lymphocytes (cCLLa-/CD5+) remained unaffected. IT potency was independent of toxin glycosylation, but was slightly influenced by antibody valence; divalent ITs were twice as potent as monovalent ITs (IC50, 2.3 v 7.1 x 10(-11) mol/L; CK, 2.6- v 2.0-log reached with 524 v 1,072 IT molecules bound/cell, respectively). In the presence of ammonium chloride or Verapamil, IT-induced CK was enhanced 10- to 80-fold. These data suggest that the cCLLa is a promising target for IT-based immunotherapy of B-CLL in vivo and ex vivo.

scholarly journals EXTH-62. PRECLINICAL EFFICACY OF THE IMIPRIDONE ONC-206 AGAINST MEDULLOBLASTOMA

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii100-ii101
Author(s):  
Tobey MacDonald ◽  
Anshu Malhotra ◽  
Jingbo Liu ◽  
Hongying Zhang ◽  
Matthew Schneiderjan ◽  
...  
Keyword(s):  
Cell Death ◽  
Malignant Glioma ◽  
Ex Vivo ◽  
Clinical Results ◽  
Normal Brain ◽  
Dependent Manner ◽  
Group 3 ◽  
Dose Dependent

Abstract Treatment for medulloblastoma (MB) is typically ineffective for MYC amplified or metastatic SHH, Group 3 and 4 subgroups. Promising preclinical and clinical results have been obtained for adult and pediatric malignant glioma treated with ONC-201, a selective antagonist of DRD2, a G-protein coupled receptor that regulates prosurvival pathways. Herein, we report the activity of ONC-201 and ONC-206, which has increased non-competitive antagonism of DRD2, against MB. We treated three different MB cell types representative of SHH- and Group 3-like cells, with varied levels of DRD2 expression, and consistently observed increased cell death in a dose-dependent manner at lower doses of ONC-206 compared to ONC-201. We also evaluated ClpP as an additional drug target in MB. ClpP is a mitochondrial protease that has been shown to directly bind and be activated by ONC 201, and is highly expressed at the protein level across pediatric MB, malignant glioma and ATRT, but not normal brain. We observed that similar to ONC-201, ONC-206 treatment of MB cells induces the restoration of mitochondrial membrane potential to the non-proliferative state, degradation of the mitochondrial substrate SDHB, reduction in survivin and elevation in ATF4 (integrated stress response). Importantly, ONC-206 treatment induced significant cell death of patient-derived SHH, WNT, and Group 3 tumors ex vivo and Group 4 cells in vitro, while having no observable toxicity in normal brain. ONC-206 treatment of a transgenic mouse model of Shh MB in vivo significantly reduces tumor growth and doubles survival time in a dose-dependent manner following 2 weeks of therapy. Additional in vivo data will be reported in preparation for a planned Phase I study of ONC-206 in children with malignant brain tumors.

Effects of different opiate agonists on melanocyte-stimulating hormone release: in vivo and in vitro studies

1980 ◽  
Vol 58 (3) ◽  
pp. 326-329 ◽  
Author(s):  
M. E. Celis
Keyword(s):  
Opioid Peptides ◽  
In Vitro Studies ◽  
Hormone Release ◽  
Low Concentration ◽  
Melanocyte Stimulating Hormone ◽  
Dose Dependent ◽  
Stimulating Hormone

The effects of Leu-enkephalin, Met-enkephalin, and β-endorphin on melanocyte-stimulating hormone (MSH) secretion were studied in vivo and in vitro. The three opioid peptides release MSH. In vitro this release is dose dependent for Met-enkephalin between 10 and 1000 ng/mL and for Leu-enkephalin between 10 and 100 ng/mL. β-Endorphin releases MSH at the low concentration of 1 ng/mL and the effect is dose dependent between 1 and 100 ng/mL. Naloxone reverses this effect. In vivo the three petptides release MSH.

In vivo, ex vivo, and in vitro studies on apelin's effect on myocardial glucose uptake

Peptides ◽  
2012 ◽  
Vol 37 (2) ◽  
pp. 320-326 ◽  
Author(s):  
Shiming Xu ◽  
Pei Han ◽  
Mei Huang ◽  
Joseph C. Wu ◽  
Chingpin Chang ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Ex Vivo ◽  
In Vitro Studies ◽  
Myocardial Glucose Uptake

Abstract 503: Antioxidant Activity Accounts for the Antiplatelet Effects of the Probucol Derivative Succinobucol

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Simon Kennedy ◽  
Fiona H Greig ◽  
Stephanie A Houston
Keyword(s):  
Antioxidant Activity ◽  
Free Radical ◽  
Platelet Aggregation ◽  
Whole Blood ◽  
Vascular Tone ◽  
Ex Vivo ◽  
Iliac Arteries ◽  
Rabbit Blood ◽  
Dose Dependent

Succinobucol is a derivative of probucol with improved partitioning into cells and potent extracellular antioxidant activity. It has antiplatelet effects ex vivo in human blood but it is unclear if this is due to antioxidant activity. We aimed to study the effect of succinobucol on free radical-modulated platelet aggregation and generation of vascular tone. We also studied platelet aggregation ex vivo in rats following acute administration of succinobucol. Rabbit blood was collected and aggregation in whole blood and platelet-rich plasma (PRP) measured using dual-wire impedance. Rabbit iliac arteries were mounted in a small artery wire myograph to measure vessel tone and the effect of free radicals and succinobucol. Rat carotid and jugular vessels were cannulated in anaesthetised animals prior to administration of succinobucol. Blood was withdrawn to measure platelet aggregation 45 minutes following injection of succinobucol. In whole blood and PRP, succinobucol (10-100μM) caused a dose-dependent reduction in collagen-induced platelet aggregation. Aggregation to collagen in PRP was significantly increased by the superoxide-generating system xanthine/xanthine oxidase (X/XO; 29.8% increase, n=4; p<0.05 vs. control) and succinobucol abolished this effect. In denuded rabbit iliac arteries incubated with excess xanthine, addition of XO (3-9mU/mL) induced a dose-dependent relaxation and this was largely abolished by succinobucol at both 10 and 100μM. Injection of 3 doses of succinobucol (50-150mg/kg) in vivo had no effect on mean arterial pressure or heart rate. However, blood removed 45minutes following the last dose of succinobucol showed a significant reduction in aggregation to collagen (reduction of 40.4% compared to control with 5μg/mL collagen; n=5, p<0.05 vs. control). The results of the current study demonstrate that the antiplatelet effects of succinobucol may be attributed to an antioxidant effect in rabbit blood and that succinobucol exerts an antiplatelet effect in vivo for at least 45mins after administration. Furthermore, the antioxidant effects may be able to influence vascular tone at sites of free radical generation in the vascular tree.

Biochemical and Pharmacologic Profiling of a Novel Dual Acting Antithrombin Agent with Antiprotease and Antiplatelet Actions. Hematologic Implications.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1876-1876
Author(s):  
Jawed Fareed ◽  
D. Hoppensteadt ◽  
W. Haque ◽  
J. Diakur ◽  
W. Jeske ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Dose Range ◽  
Coagulation System ◽  
Antithrombotic Drugs ◽  
Platelet Activity ◽  
Titration Assay ◽  
Sites Of Action ◽  
Dose Dependent

Abstract Background: The pathogenesis of thrombosis involves both cellular and humoral processes. Most antithrombotic drugs exhibit either anti-protease or anti-platelet effects. A combination of anti-protease and anti-platelet drugs provides better efficacy in the management of thrombotic disorders. A series of synthetic low molecular weight serine protease inhibitors with varying anti-platelet effects (Medicure Inc.) are being assessed for antithrombotic properties. Materials and Methods: This investigation reports on a compound with low antithrombin/high anti-platelet activity MC 45301 (A) and a compound with high antithrombin/low anti-platelet activity MC 45308 (B) activity in in-vitro and in-vivo settings used to profile antithrombotic drugs. Results: A exhibited strong anti-platelet actions as measured using ADP as an agonist (IC50=1.1 g/ml), whereas B had a higher IC50 (9.4 g/ml). In the antithrombin titration assay A (>100 μg/ml) showed a relatively higher IC50 than B (45 μg/ml). In the global anticoagulant assays, A exhibited somewhat weaker effects than B. In the Xa generation assay, both compounds exhibited similar effects. However, in the thrombin generation assays B exhibited stronger effects. In whole blood assays both compounds produced anticoagulant and anti-platelet effects. Intravenous administration of these compounds to rabbits over a dose range of 50–500 g/kg produced strong dose dependent antithrombotic actions. In comparison to direct antithrombin agents such as argatroban, at a comparable dose, B produced identical antithrombotic actions, which were disproportional to the systemic anticoagulant effects. A produced modest antithrombotic actions with minimal ex vivo clotting effects. This data is highly suggestive that compounds with dual targets are able to produce stronger antithrombotic actions relative to monotherapeutic agents. Additional studies in arterial thrombosis may provide newer insights into the antithrombotic actions of compounds with dual sites of action. Moreover, these agents may be more effective in thrombotic conditions where both platelets and the coagulation system are involved.

Platelet Activity In Vivo in Hyperlipoproteinemia – Importance of Combined Hyperlipidemia

1998 ◽  
Vol 79 (02) ◽  
pp. 268-275 ◽  
Author(s):  
Anders Bröijersén ◽  
Anders Hamsten ◽  
Mats Eriksson ◽  
Bo Angelin ◽  
Paul Hjemdahl
Keyword(s):  
Urinary Excretion ◽  
Platelet Function ◽  
Mental Stress ◽  
Ex Vivo ◽  
Platelet Activity ◽  
Leukocyte Counts ◽  
Artery Disease ◽  
Platelet Secretion

SummaryPlatelet hyperactivity in vitro is found in patients with isolated hypercholesterolemia. It is, however, less well established if platelet activity in vivo is enhanced, and if there are differences between various types of hyperlipoproteinemia.Platelet function in vivo was studied at rest and during mental stress in men with isolated hypercholesterolemia (phenotype IIa; n = 21) or combined hyperlipidemia (phenotype IIb; n = 29), and age-matched normolipidemic controls (n = 41). The urinary excretion of 11-dehydrothromboxane B2 was elevated in patients compared to controls (IIa, p <0.05; IIb, p <0.001), and higher in type IIb than in IIa patients (p <0.05). Platelet secretion, assessed as plasma β-thromboglobulin levels, was higher in type IIb patients compared to controls (p <0.01) and type IIa patients (p <0.05) during mental stress. The urinary excretion of β-thromboglobulin was also elevated in type IIb patients compared to controls (p <0.05). Platelet aggregability at rest, as measured by filtragometry ex vivo was, however, reduced in both patient groups compared to controls (p <0.05). No correlations were found between plasma lipoprotein levels and markers of platelet function in vivo. Type IIb patients had higher plasma fibrinogen levels and higher leukocyte counts than controls (p <0.05 and p <0.001) and type IIa patients (p <0.05 and p = 0.06). Thromboxane excretion was positively related to fibrinogen levels and leukocyte counts (p <0.01 for both). Preliminary data regarding serum TNF-α also indicated an elevation of this inflammatory cytokine in type IIb patients (p <0.05 vs controls).In conclusion, thromboxane generation and platelet secretion in vivo are enhanced in patients with hypercholesterolemia, and particularly so among patients with concomitant elevation of plasma triglycerides. The mechanism is unknown, but inflammatory mediators may be involved. The present findings are of interest in relation to the role of triglycerides in coronary artery disease.

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