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Vivo Testing (vivo + testing)
Selected AbstractsPreclinical Safety Assessment: In vitro , in vivo TestingBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2000Flemming Hřjelse The Safety Assessment of the results with respect to predictability for humans is discussed, as well as new tests under validation. Suggestions for changes in the future of Non-Clinical Safety tests are mentioned. [source] Hapten,protein binding: from theory to practical application in the in vitro prediction of skin sensitizationCONTACT DERMATITIS, Issue 4 2005Maja Divkovic In view of the forthcoming European Union ban on in vivo testing of cosmetic and toiletry ingredients, following the publication of the 7th amendment to the Cosmetics Directive, the search for practical, alternative, non-animal approaches is gathering pace. For the end-point of skin sensitization, the ultimate goal, i.e. the development and validation of alternative in vitro/in silico assays by 2013, may be achieved through a better understanding of the skin sensitization process on the cellular and molecular levels. One of the key molecular events in skin sensitization is protein haptenation, i.e. the chemical modification of self-skin protein(s) thus forming macromolecular immunogens. This concept is widely accepted and in theory can be used to explain the sensitizing capacity of many known skin sensitizers. Thus, the principle of protein or peptide haptenation could be used in in vitro assays to predict the sensitization potential of a new chemical entity. In this review, we consider some of the theoretical aspects of protein haptenation, how mechanisms of protein haptenation can be investigated experimentally and how we can use such knowledge in the development of novel, alternative approaches for predicting skin sensitization potential in the future. [source] Bioaccessibility studies of ferro-chromium alloy particles for a simulated inhalation scenario: A comparative study with the pure metals and stainless steelINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 3 2010Klara Midander Abstract The European product safety legislation, REACH, requires that companies that manufacture, import, or use chemicals demonstrate safe use and high level of protection of their products placed on the market from a human health and environmental perspective. This process involves detailed assessment of potential hazards for various toxicity endpoints induced by the use of chemicals with a minimum use of animal testing. Such an assessment requires thorough understanding of relevant exposure scenarios including material characteristics and intrinsic properties and how, for instance, physical and chemical properties change from the manufacturing phase, throughout use, to final disposal. Temporary or permanent adverse health effects induced by particles depend either on their shape or physical characteristics, and/or on chemical interactions with the particle surface upon human exposure. Potential adverse effects caused by the exposure of metal particles through the gastrointestinal system, the pulmonary system, or the skin, and their subsequent potential for particle dissolution and metal release in contact with biological media, show significant gaps of knowledge. In vitro bioaccessibility testing at conditions of relevance for different exposure scenarios, combined with the generation of a detailed understanding of intrinsic material properties and surface characteristics, are in this context a useful approach to address aspects of relevance for accurate risk and hazard assessment of chemicals, including metals and alloys and to avoid the use of in vivo testing. Alloys are essential engineering materials in all kinds of applications in society, but their potential adverse effects on human health and the environment are very seldom assessed. Alloys are treated in REACH as mixtures of their constituent elements, an approach highly inappropriate because intrinsic properties of alloys generally are totally different compared with their pure metal components. A large research effort was therefore conducted to generate quantitative bioaccessibility data for particles of ferro-chromium alloys compared with particles of the pure metals and stainless steel exposed at in vitro conditions in synthetic biological media of relevance for particle inhalation and ingestion. All results are presented combining bioaccessibility data with aspects of particle characteristics, surface composition, and barrier properties of surface oxides. Iron and chromium were the main elements released from ferro-chromium alloys upon exposure in synthetic biological media. Both elements revealed time-dependent release processes. One week exposures resulted in very small released particle fractions being less than 0.3% of the particle mass at acidic conditions and less than 0.001% in near pH-neutral media. The extent of Fe released from ferro-chromium alloy particles was significantly lower compared with particles of pure Fe, whereas Cr was released to a very low and similar extent as from particles of pure Cr and stainless steel. Low release rates are a result of a surface oxide with passive properties predominantly composed of chromium(III)-rich oxides and silica and, to a lesser extent, of iron(II,III)oxides. Neither the relative bulk alloy composition nor the surface composition can be used to predict or assess the extent of metals released in different synthetic biological media. Ferro-chromium alloys cannot be assessed from the behavior of their pure metal constituents. Integr Environ Assess Manag 2010;6:441,455. © 2009 SETAC [source] Weak inhibitors protect cholinesterases from strong inhibitors (paraoxon): in vitro effect of tiaprideJOURNAL OF APPLIED TOXICOLOGY, Issue 6 2005G. A. Petroianu Abstract Weak and reversible inhibitors of cholinesterases, when administered before potent organophosphorus inhibitors (pretreatment), have the ability, to a certain extent, to protect enzymes from inhibition. Such a protective effect was demonstrated in vitro for metoclopramide and ranitidine. The putative mode of protective action of these substances is, when administered in excess, competition for the active site of the enzyme with the more potent organophosphate. The present paper presents results using another benzamide with weak cholinesterase inhibitory properties: tiapride (TIA). The purpose of the study was to quantify in vitro the extent that TIA conferred protection, using paraoxon (POX) as an inhibitor, and to compare the results with existing data obtained using TIA as a protective agent against dichlorvos (DDVP). POX is a highly toxic non-neuropathic organophosphate. While the use of parathion (the inactive prodrug which is metabolically converted to POX) has been restricted in most countries, the organophosphate is still responsible for a large number of accidental or suicidal exposures. DDVP is a moderately toxic, non-neuropathic organophosphate. Red blood cell (RBC) acetylcholinesterase (AChE) activities in whole blood and butyrylcholinesterase (BChE) activities in human plasma were measured photometrically in the presence of different POX and TIA concentrations and the IC50 was calculated. Determinations were repeated in the presence of increasing TIA concentrations. The IC50 of POX increases with the TIA concentration in a linear manner. The protective effect of tiapride on cholinesterase could be of practical relevance in the pretreatment of organophosphate poisoning. It is concluded that in vivo testing of TIA as an organophosphate protective agent is warranted. Copyright © 2005 John Wiley & Sons, Ltd. [source] Pralidoxime and l -lactate effects in vitro on the inhibition of acetylcholinesterase by paraoxon: pralidoxime does not confer superior protectionJOURNAL OF APPLIED TOXICOLOGY, Issue 1 2001Georg Petroianu Abstract Intoxication with the organophosphorus compound paraoxon (POX), an inhibitor of serine hydrolases, is frequent. Although oximes are the only enzyme reactivators presently available, clinical experience with their use was rather disappointing. Recent work has shown that under certain conditions l -lactate is also able to reduce in vitro the POX inhibition of butyrylcholine- and acetylcholineesterase (BChE and AChE). To assess the practical relevance, if any, of these findings, the protective effects of pralidoxime (PRX) and those of lactate had to be compared in the same in vitro model. Effects of PRX on the inhibition of AChE by POX were assessed in vitro in plasma of 12 (six male and six female) healthy human volunteers. The determinations were repeated using different oxime and different POX concentrations. The AChE activity determinations were performed using the following sampler: sample BL,baseline (or untreated plasma); sample a,after addition of POX to plasma (pl + POX); sample b,after POX and plasma were incubated and then oxime was added (pl + POX/PRX); sample c,after addition of oxime to plasma (pl + PRX); sample d,after oxime and plasma were incubated and then POX was added (pl + PRX/POX); sample e,after oxime and POX were incubated and then added to plasma (PRX + POX/pl). Results were corrected for spurious enzyme ,pseudo-activity' due to interaction between PRX and substrate (acetylthiocholine) in the absence of enzyme. In the micro- and millimolar ranges, PRX is able to protect in vitro AChE from inhibition by POX when added to human plasma prior to POX or when incubated with POX prior to addition to plasma. Adding PRX to plasma after POX has no protective effect. The PRX results were compared statistically with historical lactate data (obtained under identical conditions) using the Wilcoxon matched pairs test, with significance assumed for p = 0.01. No difference between PRX and lactate's protective effect on the AChE inhibition by POX was found in the in vitro model used. We therefore conclude that in vivo testing of lactate as a POX protective agent is warranted. Copyright © 2001 John Wiley & Sons, Ltd. [source] Zebrafish cnbp intron1 plays a fundamental role in controlling spatiotemporal gene expression during embryonic developmentJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2009Andrea M.J. Weiner Abstract Cellular nucleic acid binding protein (CNBP) is a strikingly conserved zinc-finger nucleic acid chaperone required for forebrain development. Its depletion causes forebrain truncation mainly as a consequence of a reduction in size of craniofacial structures and neural crest derivatives. The CNBP expression pattern is complex and highly dynamic, but little is known of the underlying mechanisms regulating its spatiotemporal pattern. CNBP expression is highly conserved between all vertebrates characterized. In this study we have combined comparative sequence analysis and in vivo testing of DNA fragments in zebrafish to identify evolutionarily constrained regulatory motifs that likely control expression of the cnbp gene in embryos. We found a novel exon sequence located 5, upstream of the Exon1-sequence reported in most databases, and two transcription start sites that generate two primary-transcripts that differ in their 5,UTRs and expression profile during zebrafish embryonic development. Furthermore, we found a region inside the intron1 sequence that controls the cnbp developmental-specific transcriptional activation. Conserved binding sites for neural crest transcription factors were identified in this region. Mutagenesis analysis of the regulatory region revealed that Pax6/FoxD3 binding sites are required for proper zygotic cnbp expression. This is the first study that identifies, in vivo, cis -regulatory sequences inside intron sequences and typical neural crest transcription factors involved in cnbp spatiotemporal specific transcriptional control during vertebrate embryonic development. J. Cell. Biochem. 108: 1364,1375, 2009. © 2009 Wiley-Liss, Inc. [source] Design and testing of biological scaffolds for delivering reparative cells to target sites in the lung,JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 4 2010Edward P. Ingenito Abstract This study summarizes the development and testing of a scaffold to promote engraftment of cells in the distal lung. A fibrinogen,fibronectin,vitronectin hydrogel (FFVH) was developed and optimized with respect to its mechanical and biological properties for this application. In vitro, FFVH scaffolds promoted attachment, histiotypic growth and expression of basement membrane proteins by primary ovine lung mesenchymal cells derived from lung biopsies. In vivo testing was then performed to assess the ability of FFVHs to promote cell engraftment in the sheep lung. Treatment with autologous cells delivered using FFVH was clinically well tolerated. Cells labelled with a fluorescent dye (PKH-26) were detected at treatment sites after 1 month. Tissue mass (assessed by CT imaging) and lung perfusion (assessed by nuclear scintigraphy) were increased at emphysema test sites. Post-treatment histology demonstrated cell proliferation and increased elastin expression without scarring or collapse. No treatment-related pathology was observed at healthy control sites. FFVH scaffolds promote cell attachment, spreading and extracellular matrix expression in vitro and apparent engraftment in vivo, with evidence of trophic effects on the surrounding tissue. Scaffolds of this type may contribute to the development of cell-based therapies for patients with end-stage pulmonary diseases. Copyright © 2009 John Wiley & Sons, Ltd. [source] Characterization and comparison of commercially available mite extracts for in vivo diagnosisALLERGY, Issue 2 2010B. Brunetto To cite this article: Brunetto B, Tinghino R, Braschi MC, Antonicelli L, Pini C, Iacovacci P. Characterization and comparison of commercially available mite extracts for in vivo diagnosis. Allergy 2010; 65: 184,190. Abstract Background:, Assessment of sensitization by allergen-specific IgE testing and skin prick testing (SPT) are primary tools in routine clinical diagnosis of allergies. To perform a correct diagnosis, it is critical that the allergen reagent used contains an adequate amount of all relevant components. This study aimed at evaluating commercially available mite extracts for in vivo diagnosis from eight manufacturers. Methods:, Eight extracts from Dermatophagoides pteronyssinus and eight from Dermatophagoides farinae were analysed for total protein content by Bradford and for major allergen content by ELISA. SDS-PAGE, immunoblotting and SPT were also carried out. Results:, The protein amount ranged from 27.7 ,g/ml extract to 361.1 ,g/ml (D. pteronyssinus) and from 20.3 to 353.0 ,g/ml (D. farinae). In regards major allergen concentration, Der p 1 ranged from 9.6 to 36.2 ,g/ml, Der f 1 26.5,196.1 ,g/ml, mite group 2 0.7,31.7 ,g/ml in D. pteronyssinus and 1.3,10.4 ,g/ml in D. farinae. SDS-PAGE experiments showed that some components are poorly represented or absent in extracts from most manufacturers. Similar results were obtained by IgE-immunoblotting and SPT with 10 mite allergic patients confirmed a broad spectrum of reactivity of the extracts in the same subject. Conclusions:, Immunochemical analysis showed a heterogeneous amount of component/s among mite extracts from different manufacturers. These data were confirmed by in vivo testing, suggesting that, for some of the patient tested, the absence of relevant allergens could strongly affect the diagnosis. [source] Skin testing for immediate hypersensitivity to betalactams: comparison between two commercial kitsALLERGY, Issue 8 2006J. L. Rodríguez-Bada Introduction:, Skin testing with major and minor determinants of benzylpenicillin is the recommended standard practice to evaluate subjects with immediate hypersensitivity to betalactams. The withdrawal of these products from the market has set us back to the early days, before the introduction of reagents for in vivo testing. Objectives:, To compare a recently released kit of benzylpenicillin conjugated to poly- l -lysine (PPL) and minor determinants mixture (MDM) with the previously existing kit in a positive control group of subjects sensitized to major and/or minor determinants of benzylpenicillin. Methods:, Skin tests with both kits were made in a group of positive subjects previously diagnosed with immediate hypersensitivity to penicillins and with positive results to PPL and/or MDM and in a negative control group. Radioallergosorbent test (RAST) inhibition assays with a pool of sera and individual samples were carried out to compare the inhibition capacity of PPL and MDM of both kits. Results:, Of 22 cases selected from our historical group, 14 were positive: eight to PPL, three to MDM and three to both. These results were equivalent for both kits. RAST inhibition studies showed similar potencies in the inhibition of PPL and MDM. Conclusions:, Both tests show similar results in terms of RAST inhibition assays and skin tests sensitivity and specificity in the groups selected. The new assay can be used for the same purpose and indications as the previous test. [source] Immediate allergic reactions to cephalosporins and penicillins and their cross-reactivity in childrenPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 4 2005-Markovi, Marina Atanaskovi Penicillins and cephalosporins are the most important betalactams inducing IgE-mediated reactions. The safety of administering cephalosporins to penicillin-allergic children is a particular problem, because cephalosporin allergenic determinants have not been properly identified. A study was undertaken to evaluate the frequency of anaphylactic reactions to cephalosporins and penicillins and their cross-reactivity in a pediatric population. A prospective survey was conducted in a group of 1170 children with suspected immediate allergic reactions to cephalosporins and/or penicillins, which were examined during a period of 8 yr. In vivo (skin tests and challenges) and in vitro tests (for specific IgE) were performed with standard concentration of penicillins and cephalosporins. When 1170 children with a clinical history of allergy to penicillins and/or cephalosporins were tested in vivo for immediate hypersensitivity to betalactams, 58.3% cases overall were found to be skin or challenge test positive. Among them, 94.4% patients were positive to penicillins and 35.3% to cephalosporins. The frequency of positive reactions in the in vivo testing was in the range from 36.4% to 88.1% for penicillins and from 0.3% to 29.2% for cephalosporins. However, 31.5% of the penicillin allergic children cross-reacted to some cephalosporin. If a child was allergic to a cephalosporin, the frequency of positive reactions to penicillin was 84.2%. The cross-reactivity between cephalosporins and penicillins varied between 0.3% and 23.9%. The cross-reactivity among different generations of cephalosporins varied between 0% and 68.8%, being the highest for first and second-generation cephalosporins and 0% for third generation cephalosporins. The frequency of immediate allergic reactions to cephalosporins is considerably lower compared to penicillins, and the degree of cross-reactivity between cephalosporins and penicillins depends on the generation of cephalosporins, being higher with earlier generation cephalosporins. The cross-reactivity among cephalosporins is lower compared to cross-reactivity between penicillins and cephalosporins. [source] Casual Chocolate Consumption and Inhibition of Platelet FunctionPREVENTIVE CARDIOLOGY, Issue 4 2007Bryan Bordeaux DO Observational studies have associated reduced cardiovascular mortality with chocolate consumption. Feeding studies of high-dose, flavanol-rich chocolate show antiplatelet effects, but the effect of casual chocolate consumption on platelet function is unknown. Healthy adults (N=1535) were proscribed from consuming foods affecting platelet function, including chocolate, for 48 hours and completed a 24-hour dietary recall before ex vivo platelet testing with the Platelet Function Analyzer (PFA)-100 (Dade Behring, Inc, Deerfield, IL) test and in vivo testing with urinary 11-dehydro thromboxane B2 (Tx-M) measurements. Some participants (n=141) reported ignoring the prohibition of consuming chocolate before platelet testing. Despite having similar baseline characteristics, chocolate consumers had longer PFA closure times (130 vs 123 seconds, P=.005) and decreased Tx-M levels (175 vs 290 ng/mol creatinine, P=.03). Chocolate remained a significant independent predictor of both ex vivo and in vivo platelet function testing after adjusting for confounders. The authors concluded that even consuming modest amounts of commercial chocolate has important antiplatelet effects. [source] Review: Organotin compounds and their therapeutic potential: a report from the Organometallic Chemistry Department of the Free University of Brussels,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 9 2002Marcel Gielen Abstract An overview of the development of antitumour organotin derivatives is presented and discussed for selected classes of compounds, such as tetraorganodicarboxylatodistannoxanes and related diorganotin dicarboxylates, and for triorganotin carboxylates. Among the carboxylate groups used are steroidcarboxylates and other biologically relevant carboxylates. High to very high in vitro activities have been found, sometimes equalling that of doxorubicin. Solubility in water is an important issue, dominating the in vivo testing of compounds. Polar substituents, like fluorine or polyoxaalkyl moieties, improve the water solubility. Although organotin derivatives constitute a separate class of compounds, the comparison with cisplatin is inevitable. Among the observed toxicities, neurotoxicity, known from platinum cytostatics, and gastrointestinal toxicity, typical for many oncology drugs, have been detected, but to a lower extent. Further research to develop novel useful organotin antitumour compounds needs to be carried out. Copyright © 2002 John Wiley & Sons, Ltd. [source] Blocking vascular endothelial growth factor with soluble Flt-1 improves the chondrogenic potential of mouse skeletal muscle,derived stem cellsARTHRITIS & RHEUMATISM, Issue 1 2009Seiji Kubo Objective To investigate the effect of vascular endothelial growth factor (VEGF) stimulation and the effect of blocking VEGF with its antagonist, soluble Flt-1 (sFlt-1), on chondrogenesis, using muscle-derived stem cells (MDSCs) isolated from mouse skeletal muscle. Methods The direct effect of VEGF on the in vitro chondrogenic ability of mouse MDSCs was tested using a pellet culture system, followed by real-time quantitative polymerase chain reaction (PCR) and histologic analyses. Next, the effect of VEGF on chondrogenesis within the synovial joint was tested, using genetically engineered MDSCs implanted into rat osteochondral defects. In this model, MDSCs transduced with a retroviral vector to express bone morphogenetic protein 4 (BMP-4) were coimplanted with MDSCs transduced to express either VEGF or sFlt-1 (a VEGF antagonist) to provide a gain- and loss-of-function experimental design. Histologic scoring was used to compare cartilage formation among the treatment groups. Results Hyaline-like cartilage matrix production was observed in both VEGF-treated and VEGF-blocked (sFlt-1,treated) pellet cultures, but quantitative PCR revealed that sFlt-1 treatment improved the expression of chondrogenic genes in MDSCs that were stimulated to undergo chondrogenic differentiation with BMP-4 and transforming growth factor ,3 (TGF,3). In vivo testing of articular cartilage repair showed that VEGF-transduced MDSCs caused an arthritic change in the knee joint, and sFlt-1 improved the MDSC-mediated repair of articular cartilage, compared with BMP-4 alone. Conclusion Soluble Flt-1 gene therapy improved the BMP-4, and TGF,3-induced chondrogenic gene expression of MDSCs in vitro and improved the persistence of articular cartilage repair by preventing vascularization and bone invasion into the repaired articular cartilage. [source] The PediPump: A Versatile, Implantable Pediatric Ventricular Assist Device,Update IVARTIFICIAL ORGANS, Issue 11 2009Brian W. Duncan Abstract Cleveland Clinic's PediPump (Cleveland, OH, USA) is a ventricular assist device designed for the support of pediatric patients. The PediPump is a mixed-flow ventricular assist device with a magnetically suspended impeller measuring 10.5 mm in diameter by 64.5 mm in length. Progress and achievements for the PediPump program are considered according to the development project's three primary objectives: Basic engineering: along with size reductions, substantial design improvements have been incorporated in each design iteration including the motor, magnetic bearings, axial touch points, and heat transfer path; Anatomic modeling and device fitting studies: Techniques based on computed tomography and magnetic resonance imaging have been developed to create three-dimensional anatomic-modeling and device-fitting tools to facilitate device implantation and to assist in preoperative planning. For in vivo testing, to date, six acute (6-h duration) and nine chronic (30-day target duration) implantations have been performed in sheep; the implantation of the PediPump appears to be relatively easy with excellent hemodynamic performance and minimal hemolysis during support. Cleveland Clinic's PediPump program supported by the National Heart, Lung and Blood Institute's Pediatric Circulatory Support Program has led to the development of a pediatric ventricular assist device that has satisfactory performance in preclinical evaluation and appears to be ready to support a program of clinical testing. [source] Biodisk: A new device for closure of patent foramen ovale: A feasibility study in swine,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 6 2010Dusan Pavcnik MD Abstract Purpose: To evaluate the feasibility, effectiveness, and safety of a porcine small intestinal submucosa (SIS)-covered Biodisk (BD) for the closure of patent foramen ovale (PFO) in swine. Methods: Twelve piglets (9,30 kg) with PFO ranging in size from 6 to 12 mm were used for the in vivo testing. The BD device consisted of two basic nitinol wire components covered with platinum coil, a flexible SIS-covered ring, and an anchor. The BD was advanced through an 8-Fr sheath from the femoral vein. Nine acute animals were used to test the BD for deployment, stability, immediate shunt closure, and device repositioning before or after its detachment. To assess retrievability, four devices were deployed and intentionally embolized into the RA (n = 2) and LA (n = 2). The effectiveness of the device was evaluated by angiocardiography. EKG was recorded before and after PFO closure for 3 hr. From the 12 animals, nine were acute and three were followed; one for 6 weeks, one for 12 weeks, and one for 16 weeks. Results: Successful device implantation was achieved in all animals with no shunting of contrast media observed during follow-up in. One animal needed to have device repositioned for complete PFO occlusion because of suboptimal placement at the first attempt. The device was easily placed and retrieved before detachment in all nine animals in the acute study. None of the BDs spontaneously embolized during release or on follow-up. EKG did not demonstrate arrhythmias during or after treatment. Four intentionally embolized BDs were easily retrieved with an Amplatz goose neck snare. Macroscopic and histologic evaluation of the three long-term animals showed that devices were well incorporated in the atrial septum with complete shunt closure. The SIS showed progressive remodeling with the host cells. There was also progressive endothelization of the BD device. Conclusion: The BD device deployment is feasible, safe, and effective. Long-term studies are needed to evaluate its long-term effectiveness. © 2010 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||