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Preclinical Testing (preclinical + testing)

Distribution by Scientific Domains

Medical Sciences	77%

Selected Abstracts

Evaluation of Liver Support Systems for Preclinical Testing by Animal Trials

ARTIFICIAL ORGANS, Issue 10 2006
Oleksandr Seleverstov
Abstract:, In the present review, various animal models of acute liver failure are reviewed with respect to their suitability for evaluating liver support systems (LSS) according to envisaged modes of therapy. In order to increase the value of the preclinical testing of LSS, it would be advantageous to include more than one animal model in the evaluation program. It is possible to identify appropriate sets of models, which make a suitable test system for particular clinical applications. A standardization of evaluation methods between testing groups would also be beneficial to the field of liver support. [source]

Experimental models for hepatitis C viral infection,

HEPATOLOGY, Issue 5 2009
Andre Boonstra
Hepatitis C virus (HCV) infection is a leading cause of chronic liver disease. The majority of infected individuals develop a persistent infection, which is associated with a high risk of liver cirrhosis and hepatocellular carcinoma. Since its discovery 20 years ago, progress in our understanding of this virus has been suboptimal due to the lack of good model systems. However, in the past decade this has greatly accelerated with the development of various in vitro cell culture systems and in vivo small-animal models. These systems have made a major impact on the field of HCV research, and have provided important breakthroughs in our understanding of HCV infection and replication. Importantly, the in vitro cell culture systems and the small-animal models have allowed preclinical testing of numerous novel antiviral compounds for the treatment of chronic HCV infection. In this article, we give an overview of current models, discuss their limitations, and provide future perspectives for research directed at the prevention and cure of hepatitis C. (HEPATOLOGY 2009.) [source]

Structural and ligand-binding properties of serum albumin species interacting with a biomembrane interface

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2007
Takamitsu Kosa
Abstract In the process of drug development, preclinical testing using experimental animals is an important aspect, for verification of the efficacy and safety of a drug. Serum albumin is a major binding protein for endogenous and exogenous ligands and regulates their distribution in various tissues. In this study, the structural and drug-binding properties of albumins on a biomembrane surface were investigated using reverse micelles as a model membrane. In reverse micelles, the secondary structures of all albumins were found, to varying degrees, to be intermediate between the native and denatured states. The tertiary structures of human and bovine albumin were similar to those of the native and intermediate states, respectively, whereas those of the dog, rabbit, and rat were in a denatured state. Thus, bovine albumin is an appropriate model for studying structural changes in human albumin in a membrane-water phase. Binding studies also showed the presence of species difference in the change in binding capacity of albumins during their interaction with reverse micelles. Among the albumins, rat albumin appears to be a good model for the protein-mediated drug uptake of human albumin in a biomembrane environment. These findings are significant in terms of the appropriate extrapolation of pharmacokinetics and pharmacodynamics data in various animals to humans. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 3117,3124, 2007 [source]

Initial testing of topotecan by the pediatric preclinical testing program,

PEDIATRIC BLOOD & CANCER, Issue 5 2010
Hernan Carol PhD
Abstract Background Topotecan is a small molecule DNA topoisomerase I poison, that has been successful in clinical trials against pediatric solid tumors and leukemias. Topotecan was evaluated against the Pediatric Preclinical Testing Program (PPTP) tumor panels as part of a validation process for these preclinical models. Procedures In vivo three measures of antitumor activity were used: (1) an objective response measure modeled after the clinical setting; (2) a treated to control (T/C) tumor volume measure; and (3) a time to event (fourfold increase in tumor volume for solid tumor models, or ,25% human CD45+ cells in the peripheral blood for acute lymphoblastic leukemia, ALL models) measure based on the median event-free survival (EFS) of treated and control animals for each xenograft. Results Topotecan inhibited cell growth in vitro with IC50 values between 0.71 and 489,nM. Topotecan significantly increased EFS in 32 of 37 (87%) solid tumor xenografts and in all 8 of the ALL xenografts. Seventy-five percent of solid tumors met EFS T/C activity criteria for intermediate (n,=,17) or high activity (n,=,7). Objective responses were noted in eight solid tumor xenografts (Wilms, rhabdomyosarcoma, Ewing sarcoma, neuroblastoma). Among the six neuroblastomas, three achieved a PR. For the ALL panel, two maintained CRs, three CRs, and two PRs were observed. Conclusions Topotecan demonstrated broad activity in vitro and in vivo against both the solid tumor and ALL panels, with significant tumor growth delay generated in all the panels. These results further demonstrate the validity of the PPTP panel for preclinical testing of new drugs. Pediatr Blood Cancer 2010;54:707,715. © 2009 Wiley-Liss, Inc. [source]

Hereditary inclusion body myopathy: single patient response to GNE gene Lipoplex therapy

THE JOURNAL OF GENE MEDICINE, Issue 5 2010
Gregory Nemunaitis
Abstract Background Hereditary inclusion body myopathy (HIBM) is an autosomal recessive adult onset myopathy. It is characterized by mutations of the GNE (UDP- N -acetylglucosamine 2-epimerase/N -acetylmannosamine kinase) gene. Afflicted patients have no therapeutic options. In preclinical testing, we have previously demonstrated the ability to correct GNE gene function and the safety of delivery of wild type GNE gene using a liposomal delivery vehicle. Methods A single patient (subject #001) with severe HIBM treated by compassionate investigational new drug received four doses of GNE gene Lipoplex via intramuscular injection. GNE transgene expression, downstream induction of sialic acid, safety and muscle function were evaluated. Results Significant durable improvement in locoregional skeletal muscle function was observed in the injected left extensor carpi radialis longus of #001 in correlation with GNE transgene upregulation and local induction of sialic acid. Other than transient low grade fever and pain at the injection site, no significant toxicity was observed. Conclusions Proof of principle for manufacturing of ,clinical grade' GNE gene Lipoplex, clinical safety and activity are demonstrated with GNE gene Lipoplex. Further assessment will involve intravenous administration and subsequent phase I trial involving additional but less severely afflicted HIBM patients. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Evaluation of Liver Support Systems for Preclinical Testing by Animal Trials

Blood Biocompatibility Assessment of an Intravenous Gas Exchange Device

ARTIFICIAL ORGANS, Issue 9 2006
Trevor A. Snyder
Abstract:, To treat acute lung failure, an intravenous membrane gas exchange device, the Hattler Catheter, is currently under development. Several methods were employed to evaluate the biocompatibility of the device during preclinical testing in bovines, and potential coatings for the fibers comprising the device were screened for their effectiveness in reducing thrombus deposition in vitro. Flow cytometric analysis demonstrated that the device had the capacity to activate platelets as evidenced by significant increases in circulating platelet microaggregates and activated platelets. Thrombus was observed on 20 ± 6% of the surface area of devices implanted for up to 53 h. Adding aspirin to the antithrombotic therapy permitted two devices to remain implanted up to 96 h with reduced platelet activation and only 3% of the surface covered with thrombus. The application of heparin-based coatings significantly reduced thrombus deposition in vitro. The results suggest that with the use of appropriate antithrombotic therapies and surface coatings the Hattler Catheter might successfully provide support for acute lung failure without thrombotic complications. [source]

First Exposure in Man: Toxicological Considerations

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2000
Per Spindler
Recommendations on the type and extent of preclinical safety studies that should be conducted prior to first dose in man have been developed by the International Conference on Harmonisation, and the European Committee for Proprietary Medicinal Products. These recommendations include studies designed to characterise local tolerance and general toxicity of the drug candidate as well as its genotoxic potential and ability to interfere with reproduction. For trials which can be categorised as low dose PK screening trials and trials with products where rodent and non-rodent (primarily dog) models do not show any biological response (e.g. some biotechnology-derived hormones and cytokines) other testing paradigms should be used. The present recommendations for preclinical testing have had an important impact on the documented impressive safety record of phase I clinical trials. In this spirit we extend our warmest and sincerest thanks to Professor Jens S. Schou for his long and deep engagement in European and International harmonisation of preclinical test recommendations. His efforts have had a substantial impact on the present testing recommendations, which are of obvious benefit to the safety of the patient. [source]

Dexrazoxane protects the heart from acute doxorubicin-induced QT prolongation: a key role for IKs

BRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2010
J Ducroq
Introduction:, Doxorubicin, an anthracycline widely used in the treatment of a broad range of tumours, causes acute QT prolongation. Dexrazoxane has been shown to prevent the QT prolongation induced by another anthracycline, epirubicin, but has not yet been reported to prevent that induced by doxorubicin. Thus, the present study was designed to test whether the acute QT effects induced by doxorubicin could be blocked by dexrazoxane and to explore the mechanism. Results were compared with those obtained with a reference human ether-a-go-go (hERG) channel blocker, moxifloxacin. Methods:, The effects of moxifloxacin (100 µM) and doxorubicin (30 µM), with or without dexrazoxane (from 3 to 30 µM), have been evaluated on the QTc interval in guinea-pig isolated hearts and on IKr (rapid component of the delayed rectifier current) and IKs (slow component of the delayed rectifier current) currents stably expressed in human embryonic kidney 293 cells. Results:, Moxifloxacin (100 µM), a potent hERG blocker, prolonged QTc by 22%, and this effect was not prevented by dexrazoxane. Doxorubicin (30 µM) also prolonged QTc by 13%, did not significantly block hERG channels and specifically inhibited IKs (IC50: 4.78 µM). Dexrazoxane significantly reduced the doxorubicin-induced QTc prolongation and prevented doxorubicin-induced inhibition of IKs. Conclusion and implications:, Doxorubicin acutely prolonged the QT interval in guinea-pig heart by selective IKs blockade. This effect was prevented by dexrazoxane. This result is important because it illustrates the danger of neglecting IKs in favour of hERG screening alone, for early preclinical testing for possible induction of torsade de pointes. This article is part of a themed section on QT safety. To view this issue visit http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2010 [source]