Biological Relevance of Anti-Recombinant Hirudin Antibodies-Results from In Vitro and In Vivo Studies

SummaryThe behavior of 125I-labeled recombinant hirudin towards the uninjured and de-endothelialized rabbit aorta wall has been studied in vitro and in vivo to determine its usefulness as an indicator of thrombin activity associated with the aorta wall. Thrombin adsorbed to either sulfopropyl-Sephadex or heparin-Sepharose bound >95% of 125I-r-hirudin and the complex remained bound to the matrix. Binding of 125I-r-hirudin to the exposed aorta subendothelium (intima-media) in vitro was increased substantially if the tissue was pre-treated with thrombin; the quantity of l25I-r-hirudin bound to the de-endothelialized intima-media (i.e. balloon-injured in vitro) correlated positively with the quantity of bound 131I-thrombin (p <0.01). Aortas balloon-injured in vivo were measured for thrombin release from, and binding of 125I-r-hirudin to, the de-endothelialized intimal surface in vitro; 125I-r-hirudin binding correlated with the amount of active thrombin released (p <0.001). Uptake of 125I-r-hirudin by the aorta wall in vivo was proportional to the uptake of 131I-fibrinogen (as an indicator of thrombin activity) before and after balloon injury. After 30 min in the circulation, specific 125I-r-hirudin binding to the uninjured and de-endo- thelialized (at 1.5 h after injury) aorta wall was equivalent to 3.4 (± 2.5) and 25.6 (±18.1) fmol of thrombin/cm2 of intima-media, respectively. Possibly, only hirudin-accessible, glycosaminoglycan-bound thrombin is measured in this way.

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Effects of Unfractionated and Low Molecular Weight Heparins on Platelet Thromboxane Biosynthesis “In Vivo”

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648988 ◽

1994 ◽

Vol 72 (06) ◽

pp. 942-946 ◽

Cited By ~ 20

Author(s):

Raffaele Landolfi ◽

Erica De Candia ◽

Bianca Rocca ◽

Giovanni Ciabattoni ◽

Armando Antinori ◽

...

Keyword(s):

Molecular Weight ◽

Unfractionated Heparin ◽

Low Molecular Weight Heparin ◽

Primary Source ◽

In Vivo Studies ◽

Low Molecular Weight ◽

Heparin Administration ◽

To Receive

SummarySeveral “in vitro” and “in vivo” studies indicate that heparin administration may affect platelet function. In this study we investigated the effects of prophylactic heparin on thromboxane (Tx)A2 biosynthesis “in vivo”, as assessed by the urinary excretion of major enzymatic metabolites 11-dehydro-TxB2 and 2,3-dinor-TxB2. Twenty-four patients who were candidates for cholecystectomy because of uncomplicated lithiasis were randomly assigned to receive placebo, unfractionated heparin, low molecular weight heparin or unfractionaed heparin plus 100 mg aspirin. Measurements of daily excretion of Tx metabolites were performed before and during the treatment. In the groups assigned to placebo and to low molecular weight heparin there was no statistically significant modification of Tx metabolite excretion while patients receiving unfractionated heparin had a significant increase of both metabolites (11-dehydro-TxB2: 3844 ± 1388 vs 2092 ±777, p <0.05; 2,3-dinor-TxB2: 2737 ± 808 vs 1535 ± 771 pg/mg creatinine, p <0.05). In patients randomized to receive low-dose aspirin plus unfractionated heparin the excretion of the two metabolites was largely suppressed thus suggesting that platelets are the primary source of enhanced thromboxane biosynthesis associated with heparin administration. These data indicate that unfractionated heparin causes platelet activation “in vivo” and suggest that the use of low molecular weight heparin may avoid this complication.

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Effectiveness of the integration of quercetin, turmeric, and N-acetylcysteine in reducing inflammation and pain associated with endometriosis. In-vitro and in-vivo studies

Minerva Ginecologica ◽

10.23736/s0026-4784.20.04615-8 ◽

2020 ◽

Vol 72 (5) ◽

Author(s):

Mario Fadin ◽

Maria C. Nicoletti ◽

Marzia Pellizzato ◽

Manuela Accardi ◽

Maria G. Baietti ◽

...

Keyword(s):

In Vivo Studies

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Contribution of conformational and linear IgE epitopes to ara H 2-specific IgE-binding - in vitro and in vivo studies

10.26226/morressier.5acdc65ed462b8029238dd5f ◽

2018 ◽

Author(s):

Angelika Tscheppe

Keyword(s):

Specific Ige ◽

In Vivo Studies ◽

Ara H 2 ◽

Ige Binding

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Targeting Potassium Channels to Reprogram Glioblastoma Microenvironment: in Vitro and in Vivo Studies

Case Medical Research ◽

10.31525/ct1-nct03954691 ◽

2019 ◽

Author(s):

Keyword(s):

Potassium Channels ◽

In Vivo Studies

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Faculty Opinions recommendation of Identification of new small molecule inhibitors of cystic fibrosis transmembrane conductance regulator protein: in vitro and in vivo studies.

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

10.3410/f.1069767.522696 ◽

2007 ◽

Author(s):

Kim Barrett

Keyword(s):

Cystic Fibrosis ◽

Small Molecule ◽

Small Molecule Inhibitors ◽

In Vivo Studies ◽

Transmembrane Conductance Regulator ◽

Transmembrane Conductance ◽

Regulator Protein ◽

Cystic Fibrosis Transmembrane

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Formulation and In Vivo Evaluation of Mucoadhesive Micro-spheres of Rebamipide, a Mucoprotective Drug for GIT Disorders

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2018.11.3.2 ◽

2018 ◽

Vol 11 (3) ◽

pp. 4089-4097

Author(s):

Bhikshapathi D. V. R. N. ◽

Kanteepan P

Keyword(s):

Drug Release ◽

Entrapment Efficiency ◽

In Vivo Studies ◽

Amino Acid Derivative ◽

Release Mechanism ◽

In Vivo Evaluation ◽

In Vitro Drug Release ◽

Percentage Yield

Rebamipide, an amino acid derivative of 2-(1H)-quinolinone, is used for mucosal protection, healing of gastroduodenal ulcers, and treatment of gastritis. The current research study aimed to develop novel gastro-retentive mucoadhesive microspheres of rebamipide using ionotropic gelation technique. Studies of micromeritic properties confirmed that microspheres were free flowing with good packability. The in vitro drug release showed the sustained release of rebamipide up to 99.23 ± 0.13% within 12 h whereas marketed product displayed the drug release of 95.15 ± 0.23% within 1 h. The release mechanism from microspheres followed the zero-order and Korsmeyer-Peppas (R2 = 0.915, 0.969), respectively. The optimized M12 formulation displayed optimum features, such as entrapment efficiency 97%, particle size 61.94 ± 0.11 µm, percentage yield 98%, swelling index 95% and mucoadhesiveness was 97%. FTIR studies revealed no major incompatibility between drug and excipients. SEM confirmed the particles were of spherical in shape. Optimized formulation (M12) were stable at 40°C ± 2°C/75% RH ± 5% RH for 6 months. In vivo studies were performed and kinetic parameters like Cmax, Tmax, AUC0-t, AUC0-∞, t1/2, and Kel were calculated. The marketed product Cmax (3.15 ± 0.05 ng/mL) was higher than optimized formulation (2.58 ± 0.03 ng/mL). The optimized formulation AUC0-t (15.25 ± 1.14 ng.hr/mL), AUC0-∞ (19.42 ± 1.24 ng.hr/mL) was significantly higher than that of marketed product AUC0-t (10.21 ± 1.26 ng.hr/mL) and AUC0-∞ (13.15 ± 0.05 ng.hr/mL). These results indicate an optimized formulation bioavailability of 2.5-fold greater than marketed product.

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