Vitro Testing (vitro + testing)

Distribution by Scientific Domains

Selected Abstracts

ChemInform Abstract: Pilsicainide and Its Oxymethylene Analogue: Facile Alternative Syntheses and in vitro Testing on Human Skeletal Muscle Sodium Channels.

CHEMINFORM, Issue 1 2008
Claudio Bruno
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

P28 Interleukin-8 from keratinocytes can be used to test for contact allergy

Bolli Bjarnason
Objective:, To investigate whether secretion of interleukin-8 (IL-8) proteins by keratinocytes following in vitro exposure to a contact allergen can be used to detect contact allergy. Methods:, Suction blisters were made on skin of allergic and anergic subjects to urushiol, the contact allergen of poison ivy. Keratinocyte cultures were prepared and exposed to the allergen in vitro. Controls were the allergen solvent. Variable allergen concentrations, allergen exposure times and cell culture times were used. At the end of each culture time, IL-8 RNA and protein of the culture supernatants were analyzed by PCR and ELISA. Results:, The concentration of IL-8 in the supernatants proved to be a successful way to distinguish between subjects who patch tested positive with a non-toxic concentration of urushiol and subjects who tested negative. In the allergic subjects, a correlation was established between the dose of the allergen and the IL-8 protein concentration in the supernatants. Conclusions:, In vitro testing of contact allergies in patients makes possible an objective assessment of their allergic status without causing a booster effect or risking active sensitizations. The results indicate that the method may be used as an alternative method to animal models for testing consumer products before their marketing, thus avoiding ethical problems and problems related to interpretation of tests because of biological differences between animals and humans. [source]

Flow cytometry versus histamine release analysis of in vitro basophil degranulation in allergy to Hymenoptera venom

CYTOMETRY, Issue 1 2003
C. Lambert
Abstract Background Flow cytometry (FCM) has been proposed for specific allergy in vitro testing. We investigated its biological significance for allergy to Hymenoptera venoms and compared it with the routinely performed basophil histamine release test (HRT). Methods Blood samples from 26 allergic and 8 nonallergic donors were incubated with venom at serial concentrations. Basophils were analyzed with anti-CD45-PE-Cyanin 5, Anti-IgE-FITC, and Anti-CD63-Phycoerythrine. HRT was measured by radioimmunoassay. Results FCM was as convenient as HRT for measuring basophil reactivity in at least 87% of allergic and 75% of nonallergic subjects. CD63 outer expression was specifically induced in 91% of releaser subjects (86% on HRT) and in 1 of 10 tests in nonallergic donors, or one of six tests (16% on HRT) in allergic patients tested with an irrelevant allergen. Both methods were concordant in 85.7% of the tests. The three discordant patients had low-grade reactions and borderline biological responses on FCM (n = 2) or HRT (n = 1). Conclusions The dynamic, physiologic significance of CD63, the dose,response curve, and dependency on ethylene-diaminetetra acetic acid suggested that both tests reflect the same mechanism. Cytometry Part B (Clin. Cytometry) 52B:13,19, 2003. © 2003 Wiley-Liss, Inc. [source]

Synthesis, Cytotoxicity and Antibacterial Studies of p -Methoxybenzyl-Substituted and Benzyl-Substituted N-Heterocyclic Carbene,Silver Complexes

Siddappa Patil
Abstract p -Methoxybenzyl-substituted and benzyl-substituted N-heterocyclic carbene (NHC) [(3a,c) and (6a,c)] precursors were synthesised from the reaction of 1H -imidazole (1a), 4,5-dichloro-1H -imidazole (1b), and 1H -benzimidazole (1c) with p -methoxybenzyl bromide (2) and benzyl bromide (5). These NHC precursors were then treated with silver(I) acetate to yield the NHC,silver complexes [1,3-bis(4-methoxybenzyl)imidazol-2-ylidene]silver(I) acetate (4a), [4,5-dichloro-1,3-bis(4-methoxybenzyl)imidazol-2-ylidene]silver(I) acetate (4b), [1,3-bis(4-methoxybenzyl)benzimidazol-2-ylidene]silver(I) acetate (4c), (1,3-dibenzylimidazol-2-ylidene)silver(I) acetate (7a), (1,3-dibenzyl-4,5-dichloroimidazol-2-ylidene)silver(I) acetate (7b), and (1,3-dibenzylbenzimidazol-2-ylidene)silver(I) acetate (7c), respectively. The NHC precursor 3c, four NHC,silver complexes 4c and 7a,c were characterised by single-crystal X-ray diffraction method. The preliminary antibacterial activity of all the compounds was studied against Gram-negative bacteria Escherichia coli, and Gram-positive bacteria Staphylococcus aureus using the Kirby,Bauer disk-diffusion method. Almost all the NHC,silver complexes have shown high antibacterial activity compared to the NHC precursors. In addition, the NHC,silver complexes had their cytotoxicity investigated through MTT-based preliminary in vitro testing on the Caki-1 cell lines in order to determine their IC50 values. NHC,silver complexes 4a,c and 7a,c were found to have IC50 values of 7.3 (+/,6), 12.7(+/,3), 25.2 (+/,5), 2.5 (+/,3), 10.8 (+/,4) and 12.5 (+/,4) ,M respectively on the Caki-1 cell line. [source]

The biocompatibility of modified experimental Portland cements with potential for use in dentistry

J. Camilleri
Abstract Aim, To evaluate the biocompatibility of a group of new potential dental materials and their eluants by assessing cell viability. Methodology, Calcium sulpho-aluminate cement (CSA), calcium fluoro-aluminate cement (CFA) and glass,ionomer cement (GIC; Ketac Molar), used as the control, were tested for biocompatibility. Using a direct test method cell viability was measured quantitatively using alamarBlueÔ dye, and an indirect test method where cells were grown on material elutions and cell viability was assessed using methyltetrazolium (MTT) assay as recommended by ISO 10 993-Part 5 for in vitro testing. Statistical analysis was performed by analysis of variance and Tukey multi-comparison test method. Results, Elution collected from the prototype cements and the GIC cured for 1 and 7 days allowed high cell activity after 24 h cell exposure, which reduced after 48 h when compared to the nontoxic glass,ionomer control, but increased significantly after 72 h cell contact. Elutions collected after 28 days revealed reduced cell activity at all cell exposure times. Cells placed in direct contact with the prototype materials showed reduced cell activity when compared with the control. Conclusions, Cell growth was poor when seeded in direct contact with the prototype cements. GIC encouraged cell growth after 1 day of contact. The eluted species for all the cements tested exhibited adequate cell viability in the early ages with reduced cell activity at 28 days. Changes in the production of calcium hydroxide as a by-product of cement hydration affect the material biocompatibility adversely. [source]

A keratinocytes,melanocytes coculture system for the evaluation of active ingredients' effects on UV-induced melanogenesis

J.-F. Nicolaÿ
Synopsis A new experimental design, more reliable for in vitro testing of active ingredients' effect on ultraviolet (UV)-induced melanogenesis has been carried out. It uses a bicompartmental coculture system where cell communication between keratinocytes and melanocytes can take place. Thus, this experimental situation enables to monitor the effect of biological agents released by both cell types on melanogenesis and the interference of tested compounds with this ,paracrine linkage'. Experiments with UVB-irradiated cocultures show the importance of cell communication in the melanogenic response. In this model, the endogenous mediator, nitric oxide (NO), increased melanin production. Different compounds were tested in the coculture system, and comparison with data obtained from irradiated monocultures of melanocytes enables to distinguish a specific effect on cell communication. In addition, this more close-to-reality experimental model proved to provide a valuable first approach for the assessment of the ,bioavailability' of the tested substances. Finally, the effect of an innovative photoprotective agent capable of ,boosting' UV-induced melanogenic cell communication is presented. Résumé Un nouveau concept expérimental, plus fiable pour l,évaluation in vitro de l,effet de principes actifs sur la mélanogénèse induite par les UV, a été mis en ,uvre. Il utilise un système de co-culture à double compartiment dans lequel une communication cellulaire entre les kératinocytes et les mélanocytes peut s,établir. Ainsi, ce système expérimental permet de suivre l,effet des agents biologiques libérés par les deux types de cellules sur la mélanogénèse, et les interférences des composés testés avec ce ,lien paracrine'. Les essais avec des co-cultures irradiées aux UV montrent l,importance de la communication cellulaire dans la réponse mélanogénique. Avec ce modèle, le médiateur oxyde nitrique endogène (NO) augmente la production de mélanine. Différents composés ont été testés avec ce système de co-culture, et une comparaison avec les données obtenues à partir de monocultutres de mélanocytes irradiées permet de distinguer un effet spécifique sur la communication cellulaire. En outre, ce modèle expérimental plus proche de la réalité s,est avéré apporter une première approche valable de l,évaluation de la ,biodisponibilité' des substances testées. Enfin, l,effet d,un agent protecteur innovant capable de stimuler la communication cellulaire mélanogénique induite par les UV est décrit. [source]

In vitro testing to assess the UVA protection performance of sun care products

Applied Cosmetics) Task Force, Members of the DGK (German Society for Scientific, Sun Protection'.
Synopsis The UVA protection delivered by sunscreens is an issue of increasing importance due to the increasing knowledge about UVA-induced skin damage. In Europe there is no officially accepted method available to determine the degree of UVA protection. Therefore, the objective of the present study was to design a protocol combining the merits of an in vitro model, which are simple and reproducible, with aspects known to be relevant from in vivo studies. The principle is: an UV-transparent support to which the test product is applied, a (pre)irradiation and a transmission measurement. Transpore® tape (standard support for SPF determinations) was found to be incompatible with many preparations on prolonged contact times. Roughened quartz was adopted as a suitable alternative. Transmission measurements on this support are not reliable with a layer of 2 mg cm,2 (standard for SPF) due to detection limitations of spectrophotometers, hence a reduced layer of 0.75 mg cm,2 was adopted. Overall, it is very difficult to apply products in a reproducible thin layer on appropriate substrates. As a consequence, absolute parameters derived from the transmission profile show relatively large dispersion, whereas relative parameters, such as critical wavelength ,c[1] or UVA/UVB ratio are much less sensitive to unavoidable variations in layer thickness. An increase in deviations was observed when the samples were irradiated before measurement. It is crucial to control the output carefully (spectral distribution and even more importantly, irradiance and dose delivered) of the light source. By doing so and also taking into account the previous learning steps, a protocol was drafted and tested in a ringtest (four samples in six laboratories). The results are encouraging and show that if relative parameters (e.g. ,c, UVA/UVB ratio) are considered, the intra- as well as interlaboratory reproducibility is clearly better than can be obtained in vivo. In general, we describe a suitable method, which can be considered in any future official discussions about the methodology to determine UVA protection. Résumé La protection contre les UVA apportée par les écrans solaires est un sujet d'importance croissante en raison de la progression des connaissances concernant les dommages à la peau causés par les UVA. En Europe il n'existe pas de méthode disponible officiellement reconnue pour déterminer le degré de protection contre les UVA. Par conséquent, l'objectif de la présente étude est de concevoir un protocole associant les avantages d'un modèle in vitro, qui est simple et reproductible, avec des aspects connus comme appartenant aux études in vivo. Le principe est le suivant: un support transparent aux UV auquel le produit testé est appliqué, une (pré)irradiation et une mesure de transmission. Le ruban Transpore® (support standard pour la détermination des SPF) se révèle incompatible avec de nombreuses préparations lors de temps de contact prolongés. Le quartz rugueux est adopté comme alternative appropriée. Les mesures de transmission sur ce support ne sont pas fiables avec une couche de 2 mg/cm2 (norme pour les SPF) en raison des limites de détection des spectrophotomètres, et on adopte donc une couche réduite de 0,75 mg/cm2. Il est surtout très difficile d'appliquer des produits en une couche fine reproductible sur des substrats appropriés. En conséquence, les paramètres absolus tirés du profil de transmission montrent une assez grande dispersion, tandis que les paramètres relatifs, tels que la longueur d'onde critique ,c[l] ou le rapport UVA/UVB sont beaucoup moins sensibles aux variations inévitables de l'épaisseur de la couche. On observe une augmentation des écarts lorsque les échantillons sont irradiés avant la mesure. Il est crucial de contrôler soigneusement la sortie (distribution spectrale et encore plus important, irradiation et dose délivrée) de la source lumineuse. Dans ces conditions, et en tenant aussi compte des enseignements des étapes précédentes, un protocole a étéébauché et testé lors d'un essai tournant (quatre échantillons dans six laboratoires). Les résultats sont encourageants et montrent que si on considère les paramètres relatifs (par exemple ,c, rapport UVA/UVB), la reproductibilité intra et interlaboratoires est clairement meilleures que ce qu'on peut obtenir in vivo. D'une façon générale, nous décrivons une méthode appropriée, qui peut être considérée dans tout échange officiel futur concernant la méthodologie pour déterminer la protection contre les UVA. [source]

The new adhesion prophylaxis membrane A-part®,From in vitro testing to first in vivo results

Bernd Martin Jaenigen
Abstract Introduction: Formation of postoperative intra-abdominal adhesions is a severe problem in surgery. Apart from standard surgical procedures, a variety of different substances is available to prevent adhesions, but no universal method has been developed so far. A membrane consisting of polyvinyl alcohol (PVA) and carboxymethylcellulose (CMC) has been demonstrated to be antiadhesive. Here, the in vitro testing and first in vivo results in a rabbit sidewall model are reported. Materials and Methods: A-part® membrane contains a PVA/CMC mixture in a thickness of 40 ,m. The composition, dissolution, tensile strength, and elasticity were examined to characterize the membrane in vitro. Experiments in vivo were carried out using a ,rabbit sidewall model' in which a standardized peritoneal trauma was covered with a 5 × 6 cm A-part® membrane. Adhesion formation in A-part®-treated animals was compared with that in Adept® (15 mL/kg body weight) and untreated controls. Results: An 80/20 PVA/CMC mixture forms a stable, elastic, transparent membrane, which can easily be placed intraoperatively. The dissolution shows a half-life of about 2 weeks [day 15: (45.1 ± 4.9)% SD], which affords good adhesion protection during the initial critical phase of adhesion formation. In wet conditions, the membrane follows abdominal movements without tearing (tensile strength 5.0 ± 4.2 N/cm SD; elasticity 29.5%). In a rabbit sidewall model, A-part® membrane significantly reduced adhesion development by (83.1 ± 31.5)% SD compared with the control and the Adept group (p < 0.001). Conclusion: The properties of the A-part® membrane suggest that it may be useful as an antiadhesive in surgery. A-part® is effective in invivo testing as determined in a rabbit sidewall model. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source]

Neurostimulation systems for deep brain stimulation: In vitro evaluation of magnetic resonance imaging,related heating at 1.5 tesla

Ali R. Rezai MD
Abstract Purpose To assess magnetic resonance imaging (MRI)-related heating for a neurostimulation system (Activa® Tremor Control System, Medtronic, Minneapolis, MN) used for chronic deep brain stimulation (DBS). Materials and Methods Different configurations were evaluated for bilateral neurostimulators (Soletra® Model 7426), extensions, and leads to assess worst-case and clinically relevant positioning scenarios. In vitro testing was performed using a 1.5-T/64-MHz MR system and a gel-filled phantom designed to approximate the head and upper torso of a human subject. MRI was conducted using the transmit/receive body and transmit/receive head radio frequency (RF) coils. Various levels of RF energy were applied with the transmit/receive body (whole-body averaged specific absorption rate (SAR); range, 0.98,3.90 W/kg) and transmit/receive head (whole-body averaged SAR; range, 0.07,0.24 W/kg) coils. A fluoroptic thermometry system was used to record temperatures at multiple locations before (1 minute) and during (15 minutes) MRI. Results Using the body RF coil, the highest temperature changes ranged from 2.5°,25.3° C. Using the head RF coil, the highest temperature changes ranged from 2.3°,7.1° C.Thus, these findings indicated that substantial heating occurs under certain conditions, while others produce relatively minor, physiologically inconsequential temperature increases. Conclusion The temperature increases were dependent on the type of RF coil, level of SAR used, and how the lead wires were positioned. Notably, the use of clinically relevant positioning techniques for the neurostimulation system and low SARs commonly used for imaging the brain generated little heating. Based on this information, MR safety guidelines are provided. These observations are restricted to the tested neurostimulation system. J. Magn. Reson. Imaging 2002;15:241,250. © 2002 Wiley-Liss, Inc. [source]

Antibacterial activity of silver inorganic agent YDA filler

S. Ohashi
summary, YDA filler is an antibacterial agent that is currently in commercial dental use. In this study, we attempted to determine whether it exerts an antibacterial effect on human saliva bacteria, and to determine whether it can be used in dental materials. CFUs in 1 mL stimulated human saliva were examined using blood agar and mitis salivarius agar after immersion, with or without YDA filler. The antibacterial effect was compared with that of Ketac-Silver. Dental materials containing 5% wt YDA filler were prepared for in vitro testing on S. mutans and A. viscosus. Furthermore, we examined the in vitro cytotoxicity of experimental MMA resin containing YDA filler on HeLa cells. Human saliva bacteria and mutans streptococci showed reduced viability following exposure to YDA filler after 12 h. The concentration of silver ions released by YDA filler was below 1 ppm after 12 h. Two tested strains showed reduced viability following exposure to dental materials containing YDA filler. In another experiment, MMA resin containing YDA filler did not show cytotoxicity on HeLa cells after 24- and 48-h exposure. Thus, YDA filler may help in the development of antibacterial dental materials, such as composite resin, glass,ionomer or temporary cement. [source]

Intact fibula improves fracture healing in a rat tibia osteotomy model

Sandra J. Shefelbine
Abstract Rat tibia fractures are often used in fracture healing studies. Usually the fracture is stabilized with an intramedullary pin, which provides bending stiffness, but little torsional stiffness. The objective of this research was to determine the in vitro torsional rigidity of an osteotomized tibia with and without the fibula, and to determine if this difference influences the healing process in vivo. In vitro eleven rat tibias received an osteotomy, were stabilized with an intramedullary pin, and were tested in internal rotation to determine the torsional rigidity. The fibula was then manually broken and the torsional rigidity measured again. In vivo 18 rats received a tibial osteotomy, eight of which had an additional fractured fibula. After three weeks, the rats were sacrificed and the tibias were analyzed. Bone density in the fracture callus was measured with qCT. Bending rigidity and maximum breaking moment were determined in three-point bending. In vitro testing demonstrated that the torsional rigidity with an intact fibula was nearly two times higher than when the fibula was fractured. Though the torsional rigidity was still small in comparison with an intact bone, it resulted in a significantly different healing process in vivo. Rats with intact fibulas had significantly higher bone mineral density, bending rigidity, and maximum breaking moment compared to rats with a fractured fibula. These results indicate that torsional stability considerably affects the healing process. In a fracture model, it is critical to characterize the mechanical environment of the fracture. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]

Fabrication, characterization and in vitro evaluation of poly(D,L -lactide- co -glycolide) microparticles loaded with polyamidoamine,plasmid DNA dendriplexes for applications in nonviral gene delivery

Janjira Intra
Abstract We report, for the first time, on the preparation, characterization and in vitro testing of poly(D,L -lactide- co -glycolide) (PLGA) microparticles loaded with polyamidoamine (PAMAM),plasmid DNA (pDNA) dendriplexes. Loading of pDNA into the PLGA microparticles increased by 150% when pDNA was first complexed with PAMAM dendrimers relative to loading of pDNA alone. Scanning electron microscopy (SEM) showed that the presence of PAMAM dendrimers in the PLGA microparticles created porous features and indentations on the surface of the microparticles. Loading PLGA microparticles with PAMAM,pDNA dendriplexes lowered the average PLGA microparticle size and changed the surface charge of the microparticles from negative to positive when compared to PLGA microparticles loaded with pDNA alone. The zetapotential and buffering capacity of the microparticles increased as the generation of the PAMAM dendrimer loaded in the PLGA microparticles increased. Gel electrophoresis assays showed that all the PLGA microparticle formulations were able to entrap the pDNA within the PLGA matrix. There was no significant difference in the cytotoxicity of PLGA microparticles loaded with PAMAM,pDNA dendriplexes when compared to PLGA microparticles loaded with pDNA alone. Furthermore, and in contrast to PAMAM dendrimers alone, the generation of the PAMAM dendrimer loaded in the PLGA microparticles had no significant impact on cytotoxicity or transfection efficiencies in human embryonic kidney (HEK293) or Monkey African green kidney fibroblast-like (COS7) cells. The transfection efficiency of PLGA microparticles loaded with generation 3 (G3) PAMAM,pDNA dendriplexes was significantly higher than PLGA microparticles loaded with pDNA alone in HEK293 and COS7 cells. PLGA microparticles loaded with G3 PAMAM,pDNA dendriplexes generated equivalent transfection efficiencies as (G3 to G6) PAMAM,pDNA dendriplexes alone in COS7 cells when the transfection was carried out in serum containing media. The delivery system developed in this report has low toxicity, high pDNA loading efficiencies and high transfection efficiencies that are not reduced in the presence of serum. A delivery system with these characteristics is expected to have significant potential for translational applications. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:368,384, 2010 [source]

Development of a liquid enzyme-based ceruminolytic product

Nuria Jimenez
Abstract Various compositions for removal of human cerumen are marketed but they are not very effective. Therefore, a proteolytic enzyme-based ceruminolytic product was developed containing the enzyme, methyl trypsin, and sodium bicarbonate. Efficacy was optimized based on in vitro testing using both human and artificial cerumen preparations. Both qualitative (visual observation) and quantitative (spectrophotometric) assessments of ceruminolytic efficacy were employed. Optimal enzyme stability was observed for the aqueous formulation at pH 4, while greater ceruminolytic efficacy was observed at pH 8. The optimal concentration range of enzyme was 150,300 absorbance U/mL based on efficacy and stability considerations. An aqueous formulation containing both methyl trypsin and sodium bicarbonate was shown to be more effective than two commercial products, Murine® Ear Wax Removal Drops and Cerumenex® Ear Drops. A two-part packaging system was employed to provide adequate shelf-life. Long-term stability studies confirmed that the formulation maintained >75% enzyme stability for 24 months at 5 and 25°C and after reconstitution at room temperature for up to 1 day. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:4970,4982, 2008 [source]

Evaluation of In Vitro Apparent Protein Digestibility by Shrimp Using Gut Enzyme Extracts

Joe M Fox
Knowledge of apparent protein digestibility (APD) is required for optimization of feed formulae for the production of marine penaeid shrimp. The purpose of this study was to evaluate an in vitro method for determining APD in marine penaeid shrimp using gut enzyme extracts. A high correlation (r2 = 0.95) was shown between single-ingredient APD values for fish meal diets using in vivo methodology and those derived from in vitro testing of ingredients. A second study showed positive correlation (r2 = 0.71) between in vitro APD of selected purified and semipurified ingredients and their reported in vivo APDs. This correlation was much higher for purified ingredients (r2 = 0.93) versus less-refined ingredients (r2 = 0.24). A third trial compared in vitro APD at three different enzyme extract pH values and showed that for most protein sources, APD was significantly highest (P < 0.05) at pH = 7.0 and lower at pH = 6.1 or 7.9, indicating a neutral pH optimum for this methodology. [source]

In vitro testing of haemostatic side-effects of colloids

S. Kozek-langenecker
No abstract is available for this article. [source]

In vitro susceptibility-testing in Aspergillus species

MYCOSES, Issue 5 2008
Cornelia Lass-Flörl
Summary Aspergillus species are the most common causes of invasive mould infections in immunocompromised patients. The introduction of new antifungal agents and recent reports of resistance emerging during treatment of Aspergillus infections have highlighted the need for in vitro susceptibility-testing. Various testing procedures have been proposed, including macrodilution and microdilution, agar diffusion, disc diffusion and Etest. At present, one of the most widely used assays is the M38-A reference method for filamentous fungi, published by the Clinical Laboratory Standard Institute and the Etest. Recently, the European Committee on Antimicrobial Susceptibility-testing (EUCAST) has charged its Antifungal Susceptibility-testing Subcommittee (AFST-EUCAST) with the preparation of new guidelines for in vitro susceptibility-testing of antifungals against Aspergillus spp. (EUCAST-AFST-ASPERGILLUS) defining breakpoints. This paper reviews the available methods for antifungal susceptibility-testing in Aspergillus spp. as well as the scant data regarding the clinical implications of in vitro testing. [source]

The pediatric preclinical testing program: Description of models and early testing results,

Peter J. Houghton PhD
Abstract Background The Pediatric Preclinical Testing Program (PPTP) is an initiative supported by the National Cancer Institute (NCI) to identify novel therapeutic agents that may have significant activity against childhood cancers. The PPTP has established panels of childhood cancer xenografts and cell lines to be used for in vivo and in vitro testing. These include panels for Wilms tumor, sarcomas (rhabdomyosarcoma, Ewing sarcoma, and osteosarcoma), neuroblastoma, brain tumors (glioblastoma, ependymoma, and medulloblastoma), rhabdoid tumors (CNS and renal), and acute lymphoblastic leukemia (ALL). Here, we describe the characteristics of the in vivo tumor panels and report results for the in vivo evaluation of two standard agents, vincristine and cyclophosphamide. Procedures Solid tumors were grown subcutaneously in immune-deficient mice and tumor dimensions were measured weekly. ALL xenografts were inoculated intravenously and human CD45-positive cells were enumerated weekly. Results Vincristine-induced objective responses in 6 of 24 (25%) and cyclophosphamide-induced objective responses in 18 of 28 (64%) solid tumor models. Comparable assessments of high levels of activity for these two agents were obtained using a tumor growth delay (TGD) measure. Both agents induced regressions in each of the ALL models evaluated. Conclusions We have established 51 solid tumor and 10 ALL in vivo models. The models identify vincristine and cyclophosphamide as having broad-spectrum activity. The PPTP tumor panels appear to generally recapitulate the activity of these agents against specific childhood cancers and to have the potential for identifying novel agents having significant clinical activity. Pediatr Blood Cancer 2007;49:928,940. Published 2006 Wiley-Liss, Inc. [source]

The effect of medicinal plants of Islamabad and Murree region of Pakistan on insulin secretion from INS-1 cells

Zakir Hussain
Abstract In vitro testing of the extracts of medicinal plants collected from Islamabad and the Murree region on insulin secretagogue activity was carried out. Dried ethanol extracts of all plants (ZH1-ZH19) were dissolved in ethanol and DMSO, and tested at various concentrations (between 1 and 40 µg/mL) for insulin release from INS-1 cells in the presence of 5.5 mM glucose. Glibenclamide was used as a control. Promising insulin secretagogue activity in various plant extracts at 1, 10, 20 and 40 µg/mL was found, while in some cases a decrease in insulin secretion was also observed. Artemisia roxburghiana, Salvia coccinia and Monstera deliciosa showed insulin secretagogue activity at 1 µg/mL (p < 0.05) while Abies pindrow, Centaurea iberica and Euphorbia helioscopia were active at 10 µg/mL (p < 0.05). Extracts of Bauhinia variegata and Bergenia himalacia showed effects at 20 µg/mL (p < 0.05), and Taraxacum of,cinale and Viburnum foetens at 40 µg/mL (p < 0.05). Insulin secretagogue activity could not be detected in the extracts of Adhatoda vasica, Cassia ,stula, Chrysanthemum leucanthemum, Morus alba, Plectranthus rugosus, Peganum harmala and Olea ferruginea. The results suggest that medicinal plants of Islamabad and the Murree region of Pakistan may be potential natural resources for antidiabetic compounds. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Synthesis and cytotoxicity studies of novel anion-exchanged Titanocene Y derivatives

James Claffey
Abstract Starting from the potential anticancer drug candidate Titanocene Y {bis -[(4-methoxybenzyl)cyclopentadienyl]titanium(IV) dichloride}, anion exchange experiments were performed using silver malonate (1a) or silver cyclobutane-1,1-malonate (1b) in order to yield bis-[(4-methoxy-benzyl)cyclopentadienyl] titanium(IV) malonate (2a) and bis-[(4-methoxy-benzyl)cyclopentadienyl] titanium(IV) cyclobutane-1,1-malonate (2b). In addition, Titanocene Y was reacted with salicylic acid (3a) or 3,5-dinitro-salicylic acid (3b) in the presence of diethylamine to synthesize bis-[(4-methoxy-benzyl)cyclopentadienyl] titanium(IV) salicylate (4a) or bis-[(4-methoxy-benzyl)cyclopentadienyl] titanium(IV) 3,5-dinitro-salicylate (4b). These titanocenes had their cytotoxicity investigated through preliminary in vitro testing on the LLC-PK (pig kidney epithelial) cell line in an MTT-based assay in order to determine their IC50 values. Titanocenes 2a,b and 4a were found to have IC50 values of 74 ( ± 13) µM, 18 ( ± 5) µM and 49 ( ± 11) µM on the LLC-PK cell line, while compound 4b was found to have lost all its cytotoxic activity on this cell line. Copyright © 2010 John Wiley & Sons, Ltd. [source]

A Passively Controlled Biventricular Support Device

Nicholas Richard Gaddum
Abstract Clinical studies have reported the balancing of pump outputs to be a serious control issue for rotary biventricular support (BiVS) systems. Poor reliability of long-term, blood immersed pressure sensors encouraged the development of a new control strategy to improve their viability. A rotary BiVS device was designed and constructed with a mechanical passive controller to autoregulate pump outputs to emulate the native baroreceptor response. In vitro testing in a dual circuit, hydraulic mock circulation loop showed that the prototype was able to maintain arterial pressures when subjected to sudden induced hemodynamic destabilization. However, inlet suction was observed when sudden simulated hypertension briefly reduced venous return to the cannulated ventricle. The results have encouraged further development of the device as a means to create an inherently stable, fully passive biventricular support device. [source]

Experimental Setup to Evaluate the Performance of Percutaneous Pulmonary Valved Stent in Different Outflow Tract Morphologies

Riccardo Vismara
Abstract Percutaneous pulmonary valve implantation is a potential treatment for right ventricular outflow tract (RVOT) dysfunction. However, RVOT implantation site varies among subjects and the success of the procedure depends on RVOT morphology selection. The aim of this study was to use in vitro testing to establish percutaneous valve competency in different previously defined RVOT morphologies. Five simplified RVOT geometries (stenotic, enlarged, straight, convergent, and divergent) were manufactured by silicone dipping. A mock bench was developed to test the percutaneous valve in the five different RVOTs. The bench consists of a volumetric pulsatile pump and of a hydraulic afterload. The pump is made of a piston driven by a low inertia programmable motor. The hydraulic afterload mimics the pulmonary input impedance and its design is based on a three element model of the pulmonary circulation. The mock bench can replicate different physiological and pathological hemodynamic conditions of the pulmonary circulation. The mock bench is here used to test the five RVOTs under physiological-like conditions: stroke volume range 40,70 mL, frequency range 60,80 bpm. The valved stent was implanted into the five different RVOT geometries. Pressures upstream and downstream of the valved stent were monitored. Flow rates were measured with and without the valved stent in the five mock RVOTs, and regurgitant fraction compared between the different valved stent RVOTs. The percutaneous valved stent drastically reduced regurgitant flow if compared with the RVOT without the valve. RVOT geometry did not significantly influence the flow rate curves. Mean regurgitant fractions varied from 5% in the stenotic RVOT to 7.3% in the straight RVOT, highlighting the influence of the RVOT geometry on valve competency. The mock bench presented in this study showed the ability to investigate the influence of RVOT geometry on the competence of valved stent used for percutaneous pulmonary valve treatment. [source]

Control of Drug Release through the In Situ Assembly of Stimuli-Responsive Ordered Mesoporous Silica with Magnetic Particles

CHEMPHYSCHEM, Issue 17 2007
Shenmin Zhu Dr.
Abstract A site-selective controlled delivery system for controlled drug release is fabricated through the in situ assembly of stimuli-responsive ordered SBA-15 and magnetic particles. This approach is based on the formation of ordered mesoporous silica with magnetic particles formed from Fe(CO)5 via the surfactant-template sol-gel method and control of transport through polymerization of N-isopropyl acrylamide inside the pores. Hydrophobic Fe(CO)5 acts as a swelling agent as well as being the source of the magnetic particles. The obtained system demonstrates a high pore diameter (7.1 nm) and pore volume (0.41 cm3,g,1), which improves drug storage for relatively large molecules. Controlled drug release through the porous network is demonstrated by measuring the uptake and release of ibuprofen (IBU). The delivery system displays a high IBU storage capacity of 71.5 wt,%, which is almost twice as large as the highest value based on SBA-15 ever reported. In vitro testing of IBU loading and release exhibits a pronounced transition at around 32,°C, indicating a typical thermosensitive controlled release. [source]

Novel ceramic bone replacement material CeraBall® seeded with human mesenchymal stem cells

Timothy Douglas
Abstract Objectives: Hydroxyapatite (HA) and tricalcium phosphate (TCP) are two very common ceramic materials for bone replacement. A recently developed material for bone replacement is CeraBall®, which is a mixed HA,TCP scaffold available as porous spherical scaffolds of diameter 4 and 6 mm. Before their use as bone replacement materials in vivo, in vitro testing of these scaffolds is necessary. The goal of this study was to characterise 4 and 6 mm CeraBall® scaffolds in vitro with a view to their future use as bone replacement materials. Materials and methods: The proliferation of human mesenchymal stromal cells (hMSCs) seeded on CeraBall® scaffolds was evaluated quantitatively using the WST [Water soluble tetrazolium ((4-[3-(4- Iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1, 3-benzene disulfonate)] test and qualitatively by scanning electron microscopy (SEM). In addition, the standard MTT [(3-(4, 5-Dimenthylthiazol-2-Y1)-2, 5-Diphenyltetrazolium bromide)] biocompatibility test and cell vitality staining were performed using hMSCs. CeraBall® scaffolds were also tested for their mechanical properties. Results: SEM and WST test results showed that hMSCs proliferated on CeraBall® scaffolds over the course of 9 days. Proliferation was similar to that seen on tissue culture polystyrene (control). Cells showed a well-spread morphology and formed ,sheets' on the surface of scaffolds. Invasion of pores was observed. Good biocompatibility was demonstrated by MTT test results and cell vitality staining. Scaffolds of both 4 and 6 mm were able to withstand compressive loads of 5 N. Conclusions: CeraBall® scaffolds show good biocompatibility in vitro for hMSCs. This opens the way for in vivo applications. To cite this article: Douglas T, Liu Q, Humpe A, Wiltfang J, Sivananthan S, Warnke PH. Novel ceramic bone replacement material CeraBall® seeded with human mesenchymal stem cells. Clin. Oral Impl. Res. 21, 2010; 262,267. doi: 10.1111/j.1600-0501.2009.01818.x [source]