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Vitro Assessment (vitro + assessment)
Selected AbstractsSuperparamagnetic Hyperbranched Polyglycerol-Grafted Fe3O4 Nanoparticles as a Novel Magnetic Resonance Imaging Contrast Agent: An In Vitro AssessmentADVANCED FUNCTIONAL MATERIALS, Issue 16 2009Liang Wang Abstract Hyperbranched polyglycerol-grafted, magnetic Fe3O4 nanoparticles (HPG-grafted MNPs) are successfully synthesized by surface-initiated ring-opening multibranching polymerization of glycidol. Reactive hydroxyl groups are immobilized on the surface of 6,9,nm Fe3O4 nanoparticles via effective ligand exchange of oleic acid with 6-hydroxy caproic acid. The surface hydroxyl groups are treated with aluminum isopropoxide to form the nanosized macroinitiators. The successful grafting of HPG onto the nanoparticles is confirmed by infrared and X-ray photoelectron spectroscopy. The HPG-grafted MNPs have a uniform hydrodynamic diameter of (24.0,±,3.0) nm, and are very stable in aqueous solution, as well as in cell culture medium, for months. These nanoparticles have great potential for application as a new magnetic resonance imaging contrast agent, as evidenced by their lack of cytotoxicity towards mammalian cells, low uptake by macrophages, excellent stability in aqueous medium and magnetic fields, and favorable magnetic properties. Furthermore, the possibility of functionalizing the hydroxyl end-groups of the HPG with cell-specific targeting ligands will expand the range of applications of these MNPs. [source] A Novel In Vitro Assessment of Tissue Valve Calcification by a Continuous Flow Type MethodARTIFICIAL ORGANS, Issue 2 2000Jong-Chul Park Abstract: A dynamic flow type testing to study calcification was self-designed to investigate calcification in bioprosthetic heart valves. The apparatus consists of a container into which leaflets from a porcine aortic valve are placed, a chamber that contains calcium solution, and a peristaltic pump that provides a continuous supply of the solution toward the container. Efficacy of the apparatus was compared with the conventional batch type calcification testing at 37°C through measuring the amount of calcium and phosphate deposited by inductively coupled plasma (ICP) and scanning electron microscope (SEM). After 14 days, calcium levels detected from the calcified deposit on leaflets were 470.4 ± 37.0 ,g/cm3 in the flow type testing whereas in the batch type testing levels were 81.0 ± 6.7 ,g/cm3. Though the calcium level on the leaflet increased as the exposure time to calcium solution increased in both testings, the rate and the tendency of calcification could be assessed very rapidly by flow type testing in comparison with batch type testing. [Ca]/[P] molar ratio decreased over time, and after 14 days, the ratio was close to 1.83 ± 0.18 in the flow type testing. The ratio could not be determined in the batch type testing because the deposit was too small to assess. The descending rate of [Ca]/[P] molar ratio demonstrates that deposited calcium-complex at the earliest stage may interact with inorganic phosphate ions to create a calcified deposit mineral precursor. This in vitro dynamic flow type calcification testing was a favorable tool for rapid investigation of calcification. [source] In vitro assessment of potential mechanism-specific effects of polybrominated diphenyl ethersENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2002Daniel L. Villeneuve Abstract This study examined the ability of environmentally relevant concentrations of 10 different polybrominated diphenyl ethers (PBDEs) to induce aryl hydrocarbon receptor (AhR)-and estrogen receptor (ER)-mediated gene expression in vitro. It also examined the ability of PBDEs to displace steroid hormones from serum proteins in vitro. At concentrations ranging up to 880 ng/ml, none of the PBDEs significantly displaced tritiated 17,-estradiol (E2) or testosterone from hormone-stripped carp serum. At concentrations ranging up to 500 ng/ml, 9 of 10 PBDEs tested failed to induce ER- or AhR-mediated gene expression in MVLN and H4IIE-luc cells, respectively. One congener, 3,3,,4,4,,5-pentabromodiphenylether (BDE 126), induced significant AhR-mediated gene expression at 500 ng/ml, but the magnitude of induction was only 13% of that caused by 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD). Overall, the PBDEs tested were found to be at least 200,000 times less potent than TCDD and 50,000 times less potent than E2 for inducing AhR- and ER-mediated gene expression, respectively. [source] Exercise training in late middle-aged male Fischer 344 × Brown Norway F1-hybrid rats improves skeletal muscle aerobic functionEXPERIMENTAL PHYSIOLOGY, Issue 7 2008Andrew C. Betik The Fischer 344 × Brown Norway F1-hybrid (F344BN) rat has become an increasingly popular and useful strain for studying age-related declines in skeletal muscle function because this strain lives long enough to experience significant declines in muscle mass. Since exercise is often considered a mechanism to combat age-related declines in muscle function, determining the utility of this strain of rat for studying the effects of exercise on the ageing process is necessary. The purpose of this study was to evaluate the plasticity of skeletal muscle aerobic function in late middle-aged male rats following 7 weeks of treadmill exercise training. Training consisted of 60 min per day, 5 days per week with velocity gradually increasing over the training period according to the capabilities of individual rats. The final 3 weeks involved 2 min high-intensity intervals to increase the training stimulus. We used in situ skeletal muscle aerobic metabolic responses and in vitro assessment of muscle mitochondrial oxidative capacity to describe the adaptations of aerobic function from the training. Training increased running endurance from 11.3 ± 0.6 to 15.5 ± 0.8 min, an improvement of ,60%. Similarly, distal hindlimb muscles from trained rats exhibited a higher maximal oxygen consumption in situ (23.2 ± 1.3 versus 19.7 ± 0.8 ,mol min,1 for trained versus sedentary rats, respectively) and greater citrate synthase and complex IV enzyme activities in gastrocnemius (29 and 19%, respectively) and plantaris muscles (24 and 28%, respectively) compared with age-matched sedentary control animals. Our results demonstrate that skeletal muscles from late middle-aged rats adapt to treadmill exercise by improving skeletal muscle aerobic function and mitochondrial enzyme activities. This rat strain seems suitable for further investigations using exercise as an intervention to combat ageing-related declines of skeletal muscle aerobic function. [source] In vitro assessment of antimicrobial activity of carvacrol, thymol and cinnamaldehyde towards Salmonella serotype Typhimurium DT104: effects of pig diets and emulsification in hydrocolloidsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006W. Si Abstract Aims:, To determine the effect of pig diets in vitro on the antimicrobial activity of carvacrol, thymol and cinnamaldehyde, and to identify an emulsifier/stabilizer that can stabilize the essential oil (EO) components in aqueous solution and retain their antimicrobial activity in the presence of the diets. Methods and Results:, Emulsification of essential oil components with hydrocolloid solution was achieved by blending with a Polytron. Antimicrobial activity was measured through in vitro assays to determine the inhibition of bacterial growth by measuring the optical density at 600 nm or plating on nutrition agar after incubation of the mixtures of an EO component with the culture of Salmonella serotype Typhimurium DT104 in the presence or absence of pig diets. The results generated through the in vitro assays indicated that pig diets were able to abolish the antimicrobial activity of EOs. Xanthan, fenugreek and yellow mustard gums were the best in forming stable emulsions of five different EO components among ten different plant polysaccharides and surfactants examined. Emulsification of all the EO components in the fenugreek gum solution did not alter their antimicrobial activity. However, the antimicrobial activity of geraniol was significantly reduced when emulsified with other polysaccharides and surfactants. Both fenugreek and xanthan gum solutions were unable to protect the antimicrobial activity of carvacrol and thymol when mixed with the diets. Although cinnamaldehyde required no emulsification, but a high concentration (equivalent to at least three times of minimum bactericidal concentration for cinnamon oil) to inhibit Salmonella growth significantly in the presence of the diets, emulsification in fenugreek gum appeared to be essential for cinnamaldehyde solution to retain its antimicrobial activity during storage. Conclusions:, The diets for newly weaned pigs were a significant factor limiting the antimicrobial activity of EOs and their components. Cinnamaldehyde required a high concentration to retain its antimicrobial activity in the diets, in addition to its requirement for emulsification to stabilize its activity during the storage. Significance and Impact of the Study:, The assay with the diets used in this study for measuring the antimicrobial activity can be used in vitro for rapid and effective screening of potential antimicrobials for swine production. This study has identified polysaccharides that are able to stabilize EO component solutions. It has also identified cinnamaldehyde for further in vivo studies that may have potential in future application in controlling Salmonella and possibly other enteric pathogens in swine production. [source] Minireview: does in-vitro testing of oximes help predict their in-vivo action after paraoxon exposure?JOURNAL OF APPLIED TOXICOLOGY, Issue 6 2009D. E. Lorke Abstract K-oximes have recently been developed in the search for efficacious broad-band reactivators of acetylcholinesterase (AChE) inhibited by organophosphorus compounds (OPC). Before clinical use, their toxicity and efficacy need to be assessed, and there is clear demand for simple in vitro tests that can predict in vivo performance. This article summarizes our in vitro data obtained for conventional and experimental oximes in human and rat blood exposed to the OPC paraoxon and correlates them with our in vivo results. The intrinsic AChE inhibitory activity of oximes, as reflected by their in vitro IC50, is strongly correlated with their LD50 (rat): oximes with a high IC50 (K-27, K-48, pralidoxime and obidoxime) also show a high LD50 and are thus relatively non-toxic, whereas oximes K-105, K-108 and K-113 have a low IC50, a low LD50 and are far more toxic. The IC50 is also correlated with the in vivo capacity to protect from paraoxon-induced mortality: oximes with a higher IC50 reduce the relative risk of death more. In contrast, the protective ability as assessed in vitro by the slope of the IC50 shift (tan,), is not correlated with in vivo protection from paraoxon-induced mortality: the best in vivo protectors (K-27 and K-48) show a much lower tan, value (around 2) than K-110 and K-113 (tan, around 10), which hardly reduce the relative risk of death after paraoxon exposure. The partition coefficient logP of the individual oximes is inversely correlated with their IC50 and with their LD50 and is therefore an indicator of toxicity: strongly hydrophilic oximes tend to be less toxic than less hydrophilic ones. These data highlight the good predictive value of in vitro IC50 testing for in vivo toxicity and the limited practical significance of in vitro assessment of protective potency. Copyright © 2009 John Wiley & Sons, Ltd. [source] An in vitro assessment of the strength of porcelain veneers dependent on tooth preparationJOURNAL OF ORAL REHABILITATION, Issue 12 2000P. Hahn The treatment of teeth using veneer restorations combines aesthetic and functional improvements with a low destructive technique. Different kinds of tooth preparation techniques are described in the literature for this kind of restoration. This in vitro study aimed to examine the influence of the incisal preparation on the loadability of teeth restored with porcelain laminate veneers. Thirty-six selected mandibular incisors were randomly assigned to three groups with 12 teeth per group. In the first group, only the facial surface was prepared. In the second group, the preparation included a rounded incisal edge and a distinct chamfer lingually. The third group served as an unprepared control. Empress® veneers were then fabricated and cemented with a low viscous luting composite material. After 120 days storage in Ringer's solution, the specimens were loaded incisally to the point of failure. Statistical analysis of the results showed significant differences between the series (P=0·0103). Group 2 (with preparation of the incisal edge) exhibited the lowest fracture resistance (466±99 N) (N, mean forces). When prepared only facially, the teeth restored with Empress® veneers reached the strength of unprepared teeth. Compared with the biting force described for incisors in the literature, the in vitro loadability reached in this investigation seems to jusitify the clinical use of both preparation designs tested. [source] In vitro assessment of cytochrome P450 inhibition: Strategies for increasing LC/MS-based assay throughput using a one-point IC50 method and multiplexing high-performance liquid chromatographyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2007Tong Lin Abstract A fast and robust LC/MS-based cytochrome P450 (CYP) inhibition assay, using human liver microsomes, has been fully developed and validated for the major human liver CYPs. Probe substrates were phenacetin, diclofenac, S-mephenytoin, and dextromethorphan for CYP1A2, CYP2C9, CYP2C19, and CYP2D6, respectively. Midazolam and testosterone were chosen for CYP3A4. Furafylline, sulfaphenazole, tranylcypromine, quinidine, and ketoconazole were identified as positive control inhibitors for CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4, respectively. To increase the throughput of the assay, a one-point method was developed, using data from CYP inhibition assays conducted at one concentration (i.e., 10 µM), to estimate the drug concentration at which the metabolism of the CYP probe substrate was reduced by 50% (IC50). The IC50 values from the one-point assay were validated by correlating the results with IC50 values that were obtained with a traditional eight-point concentration,response curve. Good correlation was achieved with the slopes of the trendlines between 0.95 and 1.02 and with R2 between 0.77 and 1.0. Throughput was increased twofold by using a Cohesive multiplexing high-performance liquid chromatography system. The one-point IC50 estimate is useful for initial compound screening, while the full concentration,response IC50 method provides detailed CYP inhibition data for later stages of drug development. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 2485,2493, 2007 [source] In vitro neurotoxic properties and excitatory aminoacids concentration in the cerebrospinal fluid of amyotrophic lateral sclerosis patients.ACTA NEUROLOGICA SCANDINAVICA, Issue 2 2010Relationship with the degree of certainty of disease diagnoses Fiszman ML, Ricart KC, Latini A, Rodríguez G, Sica REP. In vitro neurotoxic properties and excitatory aminoacids concentration in the cerebrospinal fluid of amyotrophic lateral sclerosis patients. Relationship with the degree of certainty of disease diagnoses. Acta Neurol Scand: 2010: 121: 120,126. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Objective,,, To determine glutamate and aspartate levels in the cerebrospinal fluid (CSF) in patients with sporadic amyotrophic lateral sclerosis (SALS) grouped according to El Escorial diagnostic criteria, and to perform an in vitro assessment of the neurotoxicity of the CSF in murine cortical neurons. Methods,,, SALS patients were sorted according to El Escorial diagnostic criteria. Glutamate and aspartate were measured in the CSF using high performance liquid chromatography. Cultured cortical neuron viability was determined after exposure to CSF for 24 h. Results,,, Glutamate levels were elevated in 28 out of the 29 patients with definite, probable or possible SALS. There were no differences in glutamate concentrations when the three clinical forms of the disease were compared; neither there were significant variation across disease duration and clinical presentation. In agreement with previous reports, we concluded that CSF-SALS-induced in vitro neurotoxicity is mediated by ionotropic glutamate receptors. We found no relationship between the degree of in vitro neurotoxicity and glutamate concentration in the CSF. Conclusions,,, Glutamate but not aspartate CSF levels may contribute to ALS pathogenesis. However, glutamate levels may not influence the degree of diagnosis certainty or lesion extension. [source] In vivo effects of interleukin-17 on haematopoietic cells and cytokine release in normal miceCELL PROLIFERATION, Issue 6 2004G. Jov Simultaneously, the release of IL-6, IL-10, IGF-I, IFN-, and NO by bone marrow cells was determined. Results showed that, in bone marrow, IL-17 did not affect granulocyte-macrophage (CFU-GM) progenitors, but induced a persistant increase in the number of morphologically recognizable proliferative granulocytes (PG) up to 48 h after treatment. The number of immature erythroid (BFU-E) progenitors was increased at 48 h, while the number of mature erythroid (CFU-E) progenitors was decreased up to 48 h. In peripheral blood, white blood cells were increased 6 h after treatment, mainly because of the increase in the number of lymphocytes. IL-17 also increased IL-6 release and NO production 6 h after administration. Additional in vitro assessment on bone marrow highly enriched Lin, progenitor cells, demonstrated a slightly enhancing effect of IL-17 on CFU-GM and no influence on BFU-E, suggesting the importance of bone marrow accessory cells and secondary induced cytokines for IL-17 mediated effects on progenitor cells. Taken together, these results demonstrate that in vivo IL-17 affects both granulocytic and erythroid lineages, with more mature haematopoietic progenitors responding first to its action. The opposite effects exerted on PG and CFU-E found at the same time indicate that IL-17, as a component of a regulatory network, is able to intervene in mechanisms that shift haematopoiesis from the erythroid to the granulocytic lineage. [source] Photocaged Agonist for an Analogue-Specific form of the Vitamin D ReceptorCHEMBIOCHEM, Issue 7 2007John B. Biggins Dr. Abstract Nuclear hormone receptors (NHRs) represent a diverse class of ligand-dependent transcriptional regulators. NHRs that have been rendered functionally inactive due to mutations that abrogate proper ligand binding can often be rescued by appropriately designed hormone analogues. The analogue-specific receptor,ligand pairs provide an ideal platform from which to develop new chemogenomic tools for the spatial and temporal control of gene expression. Here, we describe the synthesis and in vitro assessment of a photocaged VDR agonist specific to a mutant NHR that is associated with vitamin D-resistant rickets. The results provide insight into the utility of the agonist as a potential tool for photoinduced gene patterning. [source] | ||||||||||||||||