A novel Bim-BH3-derived Bcl-XL inhibitor: Biochemical characterization, in vitro, in vivo and ex-vivo anti-leukemic activity

SummaryInsights into hemostasis and thrombosis have historically benefited from the astute diagnosis of human bleeding and thrombotic disorders followed by decades of careful biochemical characterization. This work has set the stage for the development of a number of mouse models of hemostasis and thrombosis generated by gene targeting strategies in the mouse genome. The utility of these models is the in depth analysis that can be performed on the precise molecular interactions that support hemostasis and thrombosis along with efficacy testing of various therapeutic strategies. Already the mouse has proven to be an excellent model of the processes that support hemostasis and thrombosis in the human vasculature. A brief summary of the salient phenotypes from knockout mice missing key platelet receptors is presented, including the glycoprotein (GP) Ib-IX-V and GP IIb/IIIa (αIIb/β3) receptors; the collagen receptors, GP VI and α2/β1; the protease activated receptors (PARs); and the purinergic receptors, P2Y1 and P2Y12. A few differences exist between mouse and human platelets and where appropriate those will be highlighted in this review. Concluding remarks focus on the importance of understanding the power and limitations of various in vitro, ex vivo and in vivo models currently being used and the impact of the mouse strain on the described platelet phenotype.

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The in vivo distribution and dynamics of DNA topoisomerase II in Drosophila embryonic nuclei and chromosomes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146217 ◽

1993 ◽

Vol 51 ◽

pp. 74-75

Author(s):

Jason R. Swedlow ◽

Neil Osheroff ◽

Tim Karr ◽

John W. Sedat ◽

David A. Agard

Keyword(s):

Topoisomerase Ii ◽

Biochemical Characterization ◽

Developmental Cycle ◽

Dna Topoisomerase Ii ◽

Chromosomal Distribution ◽

Dna Topoisomerase ◽

Ideal System ◽

Dnase Treatment

DNA topoisomerase II is an ATP-dependent double-stranded DNA strand-passing enzyme that is necessary for full condensation of chromosomes and for complete segregation of sister chromatids at mitosis in vivo and in vitro. Biochemical characterization of chromosomes or nuclei after extraction with high-salt or detergents and DNAse treatment showed that topoisomerase II was a major component of this remnant, termed the chromosome scaffold. The scaffold has been hypothesized to be the structural backbone of the chromosome, so the localization of topoisomerase II to die scaffold suggested that the enzyme might play a structural role in the chromosome. However, topoisomerase II has not been studied in nuclei or chromosomes in vivo. We have monitored the chromosomal distribution of topoisomerase II in vivo during mitosis in the Drosophila embryo. This embryo forms a multi-nucleated syncytial blastoderm early in its developmental cycle. During this time, the embryonic nuclei synchronously progress through 13 mitotic cycles, so this is an ideal system to follow nuclear and chromosomal dynamics.

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The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000116 ◽

2012 ◽

Vol 82 (3) ◽

pp. 228-232 ◽

Cited By ~ 7

Author(s):

Mauro Serafini ◽

Giuseppa Morabito

Keyword(s):

Antioxidant Capacity ◽

Dietary Intervention ◽

Ex Vivo ◽

The Body ◽

Dietary Polyphenols ◽

Enzymatic Antioxidant ◽

Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

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Kutane antioxidative Wirkung von Johanniskrautextrakt (Hypericum perforatum): In-vitro-, Ex-vivo- und In-vivo-Untersuchungen

Zeitschrift für Phytotherapie ◽

10.1055/s-0032-1313268 ◽

2012 ◽

Vol 33 (S 01) ◽

Author(s):

MC Meinke ◽

S Schanzer ◽

S Arndt ◽

A Kleemann ◽

J Lademann

Keyword(s):

Hypericum Perforatum ◽

Ex Vivo ◽

Antioxidative Wirkung

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Significance of Platelet β-Adrenoceptors for Platelet Responses In Vivo and In Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646345 ◽

1992 ◽

Vol 68 (06) ◽

pp. 687-693 ◽

Cited By ~ 24

Author(s):

P T Larsson ◽

N H Wallén ◽

A Martinsson ◽

N Egberg ◽

P Hjemdahl

Keyword(s):

Ex Vivo ◽

High Dose ◽

Platelet Aggregability ◽

Adrenoceptor Agonist ◽

Dose Infusion ◽

Von Willebrand ◽

Willebrand Factor ◽

Factor Antigen

SummaryThe significance of platelet β-adrenoceptors for platelet responses to adrenergic stimuli in vivo and in vitro was studied in healthy volunteers. Low dose infusion of the β-adrenoceptor agonist isoprenaline decreased platelet aggregability in vivo as measured by ex vivo filtragometry. Infusion of adrenaline, a mixed α- and β-adrenoceptor agonist, increased platelet aggregability in vivo markedly, as measured by ex vivo filtragometry and plasma β-thromboglobulin levels. Adrenaline levels were 3–4 nM in venous plasma during infusion. Both adrenaline and high dose isoprenaline elevated plasma von Willebrand factor antigen levels β-Blockade by propranolol did not alter our measures of platelet aggregability at rest or during adrenaline infusions, but inhibited adrenaline-induced increases in vWf:ag. In a model using filtragometry to assess platelet aggregability in whole blood in vitro, propranolol enhanced the proaggregatory actions of 5 nM, but not of 10 nM adrenaline. The present data suggest that β-adrenoceptor stimulation can inhibit platelet function in vivo but that effects of adrenaline at high physiological concentrations are dominated by an α-adrenoceptor mediated proaggregatory action.

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In Vivo Effect of Suloctidil as an Antiplatelet Agent

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646799 ◽

1979 ◽

Vol 41 (03) ◽

pp. 465-474 ◽

Cited By ~ 7

Author(s):

Marcia R Stelzer ◽

Thomas S Burns ◽

Robert N Saunders

Keyword(s):

Ex Vivo ◽

Antiplatelet Agent ◽

Ratio Method ◽

Platelet Aggregate ◽

Permanent Effect ◽

Platelet Aggregates ◽

5 Ht Uptake ◽

High Doses

SummaryThe relationship between the effects of suloctidil in vivo as an antiplatelet agent and in vitro as a modifier of platelet serotonin (5-HT) parameters was investigated. Suloctidil was found to be effective in reducing platelet aggregates formation in the retired breeder rat as determined using the platelet aggregate ratio method (PAR) with an ED50 of 16.1 mg/kg 24 hours post administration. In contrast to the hypothesis that 5-HT depletion is involved in the anti-aggregatory mechanism of suloctidil, no correlation was found between platelet 5- HT content and this antiplatelet activity. Reduction of platelet 5-HT content required multiple injections of high doses (100 mg/kg/day) of suloctidil. Suloctidil administration for 8 days at 100 mg/kg/day, which lowered platelet 5-HT content by 50%, resulted in no permanent effect on ex vivo platelet 5-HT uptake or thrombin-induced release, nor alteration in the plasma 5-HT level. However, these platelets exhibited a short-lived, significant increase in percent leakage of 5-HT after 30 minutes of incubation. Therefore, suloctidil treatment at high doses may with time result in platelet 5-HT depletion, however this effect is probably not related to the primary anti-aggregatory activity of the drug.

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A Comparative Ex Vivo Study of Plasminogen Activators and Proteases for Fibrinolytic Activity and Side Effects in Rabbits

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649213 ◽

1977 ◽

Vol 37 (01) ◽

pp. 154-161 ◽

Cited By ~ 1

Author(s):

B. A Janik ◽

S. E Papaioannou

Keyword(s):

Side Effects ◽

Effective Dose ◽

Fibrinolytic Activity ◽

Ex Vivo ◽

Plasminogen Activators ◽

Assay System ◽

Coagulation Parameters ◽

Ex Vivo Assay

SummaryUrokinase, streptokinase, Brinase, trypsin, and SN 687, a bacterial exoprotease, have been evaluated in an ex vivo assay system. These enzymes were injected into rabbits and the fibrinolytic activity as well as other coagulation parameters were measured by in vitro techniques. Dose-response correlations have been made using the euglobulin lysis time as a measure of fibrinolytic activity and the 50% effective dose has been determined for each enzyme. Loading doses, equal to four times the 50% effective dose, were administered to monitor potential toxicity revealing that Brinase, trypsin, and SN 687 were very toxic at this concentration.Having established the 50% effective dose for each enzyme, further testing was conducted where relevant fibrinolytic and coagulation parameters were measured for up to two days following a 50% effective dose bolus injection of each enzyme. Our results have demonstrated that urokinase and streptokinase are plasminogen activators specifically activating the rabbit fibrinolytic system while Brinase, trypsin and SN 687 increase the general proteolytic activity in vivo.The advantages of this ex vivo assay system for evaluating relative fibrinolytic potencies and side effects for plasminogen activators and fibrinolytic proteases have been discussed.

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Organische Nitrate und Thrombozytenfunktion

Hämostaseologie ◽

10.1055/s-0038-1659867 ◽

1988 ◽

Vol 08 (02) ◽

pp. 90-99 ◽

Cited By ~ 7

Author(s):

H. Schröder ◽

K. Schrör

Keyword(s):

Endothelial Cell ◽

Angina Pectoris ◽

Ex Vivo

ZusammenfassungOrganische Nitrate unterschiedlicher chemischer Struktur sowie Nitroprussidnatrium und Molsidomin (bzw. ihre biologisch aktiven Metaboliten) können die (primäre) Aggregation und Sekretion von Humanthrombozyten in vitro und ex vivo hemmen. Eine solche Wirkung wird für Molsidomin (SIN-1) und Nitroprussidnatrium in vitro in Konzentrationen beobachtet, die in der gleichen Größenordnung liegen wie die vasodilatierenden Effekte der Substanzen. Dagegen sind für eine direkte Antiplättchenwirkung organischer Nitrate (Glyzeryltrinitrat, Isosorbiddinitr at, Isosorbidmononitrate, Teopranitol) in vitro Konzentrationen erforderlich, die ca. 100- bis 1000fach höher sind als die Plasmaspiegel der Substanzen nach therapeutischer Dosierung bzw. die Konzentrationen, die isolierte Gefäßstreifen relaxieren. Als gemeinsamer Wirkungsmechanismus der direkten thrombozy-tenfunktionshemmenden und gefäßerweiternden Wirkung all dieser Substanzen kann heute eine Stickoxid-(NO)-vermittelte Stimulation der cGMP-Bildung angenommen werden, das aus organischen Nitraten als »Pro-drug« entsteht. Die Freisetzung von NO, eines »endothelial cell-derived relaxing factors« (EDRF) aus Nitroprussidnatrium und SIN-1 erfolgt spontan. Dagegen erfordert die Freisetzung von NO aus organischen Nitraten einen enzymatischen Stoffwechselweg, der in isolierten Thrombozyten nicht vorhanden ist. Eine Antiplättchenwirkung organischer Nitrate in vivo bzw. ex vivo wird daher über die Stimulation eines endothelialen, thrombozyteninhibitorischen Faktors erklärt. Hierbei sind Prostazyklin sowie ein bisher unbekannter Endothel-zellfaktor neben einer synergistischen Wirkung organischer Nitrate mit endogenem Prostazyklin in Diskussion. Eine thrombozytenfunktionshemmen-de Wirkung organischer Nitrate könnte in Kombination mit ihren hämody-namischen Effekten auch für die an-tianginöse Wirkung in der Klinik bedeutsam sein, insbesondere zur Verhinderung vasospastischer Zustände bei der instabilen Angina pectoris.

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Faculty Opinions recommendation of Luciferase-expressing Leishmania infantum allows the monitoring of amastigote population size, in vivo, ex vivo and in vitro.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.720295524.793509922 ◽

2015 ◽

Author(s):

Malcolm McConville

Keyword(s):

Population Size ◽

Leishmania Infantum ◽

Ex Vivo

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Repurposing N,N-Dimethylacetamide (DMA), a Pharmaceutical Excipient, as a Prototype Novel Anti-inflammatory Agent for the Prevention and/or Treatment of Preterm Birth

Current Pharmaceutical Design ◽

10.2174/1381612824666180130121706 ◽

2018 ◽

Vol 24 (9) ◽

pp. 989-992 ◽

Cited By ~ 4

Author(s):

Samir Gorasiya ◽

Juliet Mushi ◽

Ryan Pekson ◽

Sabesan Yoganathan ◽

Sandra E. Reznik

Keyword(s):

Preterm Birth ◽

Ex Vivo ◽

The United States ◽

Occurrence Rate ◽

Pharmaceutical Excipient ◽

Ongoing Work ◽

Exciting Line ◽

Pregnant Mice

Background: Preterm birth (PTB), or birth that occurs before 37 weeks of gestation, accounts for the majority of perinatal morbidity and mortality. As of 2016, PTB has an occurrence rate of 9.6% in the United States and accounts for up to 18 percent of births worldwide. Inflammation has been identified as the most common cause of PTB, but effective pharmacotherapy has yet to be developed to prevent inflammation driven PTB. Our group has discovered that N,N-dimethylacetamide (DMA), a readily available solvent commonly used as a pharmaceutical excipient, rescues lipopolysaccharide (LPS)-induced timed pregnant mice from PTB. Methods: We have used in vivo, ex vivo and in vitro approaches to investigate this compound further. Results: Interestingly, we found that DMA suppresses cytokine secretion by inhibiting nuclear factor-kappa B (NF-κB). In ongoing work in this exciting line of investigation, we are currently investigating structural analogs of DMA, some of them novel, to optimize this approach focused on the inflammation associated with PTB. Conclusion: Successful development of pharmacotherapy for the prevention of PTB rests upon the pursuit of multiple strategies to solve this important clinical challenge.

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