This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ http://www.biomagres.commostviewed/ Most viewed articles in last 30 days from BioMagnetic Research and Technology (ISSN 1477-044X) published by BioMed Central Background: We have developed magnetite cationic liposomes (MCLs) and applied them as a mediator of local hyperthermia. MCLs can generate heat under an alternating magnetic field (AMF). In this study, the in vivo effect of hyperthermia mediated by MCLs was examined using 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary cancer as a spontaneous cancer model.MethodMCLs were injected into the mammary cancer and then subjected to an AMF. Results: Four rats in 20 developed mammary tumors at more than 1 site in the body. The first-developed tumor in each of these 4 rats was selected and heated to over 43°C following administration of MCLs by an infusion pump. After a series of 3 hyperthermia treatments, treated tumors in 3 of the 4 rats were well controlled over a 30-day observation period. One of the 4 rats exhibited regrowth after 2 weeks. In this rat, there were 3 sites of tumor regrowth. Two of these regrowths were reduced in volume and regressed completely after 31 days, although the remaining one grew rapidly. These results indicated hyperthermia-induced immunological antitumor activity mediated by the MCLs. Conclusion: Our results suggest that hyperthermic treatment using MCLs is effective in a spontaneous cancer model. http://www.biomagres.com/content/6/1/2 Jun Motoyama, Noriyuki Yamashita, Tomio Morino, Masashi Tanaka, Takeshi Kobayashi and Hiroyuki Honda BioMagnetic Research and Technology 2008, 6:2 Number of accesses: 409 2008-02-25 doi:10.1186/1477-044X-6-2 BioMagnetic Research and Technology 1477-044X 6 2 2008-02-25 Isolation and separation of specific molecules is used in almost all areas of biosciences and biotechnology. Diverse procedures can be used to achieve this goal. Recently, increased attention has been paid to the development and application of magnetic separation techniques, which employ small magnetic particles. The purpose of this review paper is to summarize various methodologies, strategies and materials which can be used for the isolation and purification of target proteins and peptides with the help of magnetic field. An extensive list of realised purification procedures documents the efficiency of magnetic separation techniques. http://www.biomagres.com/content/2/1/7 Ivo Safarik and Mirka Safarikova BioMagnetic Research and Technology 2004, 2:7 Number of accesses: 343 2004-11-26 doi:10.1186/1477-044X-2-7 BioMagnetic Research and Technology 1477-044X 2 7 2004-11-26 A series of experiments on rats have been performed, to study the effects of long time (50 days) exposure to electromagnetic fields of extremely low frequency (ELF, i.e. less than 100 Hz) and amplitude (non thermal), testing whether the metabolic processes would be affected. The background lies on recent observations on the behaviour of isolated enzymes in vitro exposed to EFL fields. In these experiments, the cyclotron (or Larmor) frequency of the metallic ion has been used to "stimulate" the metalloproteins redox-active site, thus obtaining a clear variation of the enzyme functionality. In this paper we have extended for the first time the check to more complex animal metabolism. The novelty of this approach implies that a large amount of data had to be analyzed since it was not possible, in principle, to select only a few parameters among all the potential effects. Several biochemical parameters have been evaluated by comparing their values during the periods of exposure (field ON) and non exposure (field OFF). The evidence that long term exposure to electromagnetic fields with a well defined frequency may have relevant effects on parameters such as body weight, blood glucose and fatty acid metabolism has been obtained. http://www.biomagres.com/content/6/1/3 Gabriele Gerardi, Antonella De Ninno, Marco Prosdocimi, Vanni Ferrari, Filippo Barbaro, Sandro Mazzariol, Daniele Bernardini and Getullio Talpo BioMagnetic Research and Technology 2008, 6:3 Number of accesses: 325 2008-04-01 doi:10.1186/1477-044X-6-3 BioMagnetic Research and Technology 1477-044X 6 3 2008-04-01 The aim of this study was to prepare biodegradable sustained release magnetite microspheres sized between 1 to 2 μm. The microspheres with or without magnetic materials were prepared by a W/O/W double emulsion solvent evaporation technique using poly(lactide-co-glycolide) (PLGA) as the biodegradable matrix forming polymer. Effects of manufacturing and formulation variables on particle size were investigated with non-magnetic microspheres. Microsphere size could be controlled by modification of homogenization speed, PLGA concentration in the oil phase, oil phase volume, solvent composition, and polyvinyl alcohol (PVA) concentration in the outer water phase. Most influential were the agitation velocity and all parameters that influence the kinematic viscosity of oil and outer water phase, specifically the type and concentration of the oil phase. The magnetic component yielding homogeneous magnetic microspheres consisted of magnetite nanoparticles of 8 nm diameter stabilized with a polyethylene glycole/polyacrylic acid (PEG/PAA) coating and a saturation magnetization of 47.8 emu/g. Non-magnetic and magnetic microspheres had very similar size, morphology, and size distribution, as shown by scanning electron microscopy. The optimized conditions yielded microspheres with 13.7 weight% of magnetite and an average diameter of 1.37 μm. Such biodegradable magnetic microspheres seem appropriate for vascular administration followed by magnetic drug targeting. http://www.biomagres.com/content/5/1/2 Hong Zhao, Jeffrey Gagnon and Urs O Häfeli BioMagnetic Research and Technology 2007, 5:2 Number of accesses: 310 2007-04-04 doi:10.1186/1477-044X-5-2 BioMagnetic Research and Technology 1477-044X 5 2 2007-04-04 Background: Magnetic nanoparticles have been significantly used for coupling with biomolecules, due to their unique properties. Methods: Magnetic nanoparticles were synthesized by thermal co-precipitation of ferric and ferrous chloride using two different base solutions. Glucose oxidase was bound to the particles by direct attachment via carbodiimide activation or by thiophene acetylation of magnetic nanoparticles. Transmission electron microscopy was used to characterize the size and structure of the particles while the binding of glucose oxidase to the particles was confirmed using Fourier transform infrared spectroscopy. Results: The direct binding of glucose oxidase via carbodiimide activity was found to be more effective, resulting in bound enzyme efficiencies between 94–100% while thiophene acetylation was 66–72% efficient. Kinetic and stability studies showed that the enzyme activity was more preserved upon binding onto the nanoparticles when subjected to thermal and various pH conditions. The overall activity of glucose oxidase was improved when bound to magnetic nanoparticles Conclusion: Binding of enzyme onto magnetic nanoparticles via carbodiimide activation is a very efficient method for developing bioconjugates for biological applications http://www.biomagres.com/content/3/1/1 Gilles K Kouassi, Joseph Irudayaraj and Gregory McCarty BioMagnetic Research and Technology 2005, 3:1 Number of accesses: 287 2005-03-11 doi:10.1186/1477-044X-3-1 BioMagnetic Research and Technology 1477-044X 3 1 2005-03-11 Magnetic separation technology, using magnetic particles, is quick and easy method for sensitive and reliable capture of specific proteins, genetic material and other biomolecules. The technique offers an advantage in terms of subjecting the analyte to very little mechanical stress compared to other methods. Secondly, these methods are non-laborious, cheap and often highly scalable. Moreover, techniques employing magnetism are more amenable to automation and miniaturization. Now that the human genome is sequenced and about 30,000 genes are annotated, the next step is to identify the function of these individual genes, carrying out genotyping studies for allelic variation and SNP analysis, ultimately leading to identification of novel drug targets. In this post-genomic era, technologies based on magnetic separation are becoming an integral part of todays biology laboratory. This article briefly reviews the selected applications of magnetic separation techniques in the field of biotechnology, biomedicine and drug discovery. http://www.biomagres.com/content/1/1/2 ZM Saiyed, SD Telang and CN Ramchand BioMagnetic Research and Technology 2003, 1:2 Number of accesses: 267 2003-09-18 doi:10.1186/1477-044X-1-2 BioMagnetic Research and Technology 1477-044X 1 2 2003-09-18 Background: To quantitatively compare in-vitro and in vivo membrane transport studies of targeted delivery, one needs characterization of the magnetically-induced mobility of superparamagnetic iron oxide nanoparticles (SPION). Flux densities, gradients, and nanoparticle properties were measured in order to quantify the magnetic force on the SPION in both an artificial cochlear round window membrane (RWM) model and the guinea pig RWM. Methods: Three-dimensional maps were created for flux density and magnetic gradient produced by a 24-well casing of 4.1 kilo-Gauss neodymium-iron-boron (NdFeB) disc magnets. The casing was used to pull SPION through a three-layer cell culture RWM model. Similar maps were created for a 4 inch (10.16 cm) cube 48 MGOe NdFeB magnet used to pull polymeric-nanoparticles through the RWM of anesthetized guinea pigs. Other parameters needed to compute magnetic force were nanoparticle and polymer properties, including average radius, density, magnetic susceptibility, and volume fraction of magnetite. Results: A minimum force of 5.04 × 10-16 N was determined to adequately pull nanoparticles through the in-vitro model. For the guinea pig RWM, the magnetic force on the polymeric nanoparticles was 9.69 × 10-20 N. Electron microscopy confirmed the movement of the particles through both RWM models. Conclusion: As prospective carriers of therapeutic substances, polymers containing superparamagnetic iron oxide nanoparticles were succesfully pulled through the live RWM. The force required to achieve in vivo transport was significantly lower than that required to pull nanoparticles through the in-vitro RWM model. Indeed very little force was required to accomplish measurable delivery of polymeric-SPION composite nanoparticles across the RWM, suggesting that therapeutic delivery to the inner ear by SPION is feasible. http://www.biomagres.com/content/5/1/1 Allison L Barnes, Ronald A Wassel, Fadee Mondalek, Kejian Chen, Kenneth J Dormer and Richard D Kopke BioMagnetic Research and Technology 2007, 5:1 Number of accesses: 259 2007-01-04 doi:10.1186/1477-044X-5-1 BioMagnetic Research and Technology 1477-044X 5 1 2007-01-04 In this paper we studied the effects of external fields' polarization on the coupling of pure magnetic fields into human body. Finite Difference Time Domain (FDTD) method is used to calculate the current densities induced in a 1 cm resolution anatomically based model with proper tissue conductivities. Twenty different tissues have been considered in this investigation and scaled FDTD technique is used to convert the results of computer code run in 15 MHz to low frequencies which are encountered in the vicinity of industrial induction heating and melting devices. It has been found that external magnetic field's orientation due to human body has a pronounced impact on the level of induced currents in different body tissues. This may potentially help developing protecting strategies to mitigate the situations in which workers are exposed to high levels of external magnetic radiation. http://www.biomagres.com/content/5/1/3 Laleh Golestani-Rad, Behzad Elahi and Jalil Rashed-Mohassel BioMagnetic Research and Technology 2007, 5:3 Number of accesses: 244 2007-05-15 doi:10.1186/1477-044X-5-3 BioMagnetic Research and Technology 1477-044X 5 3 2007-05-15 In the present work the results of the known investigation of the influence of combined static (40 μT) and alternating (amplitude of 40 nT) parallel magnetic fields on the current through the aqueous solution of glutamic acid, were successfully replicated. Fourteen experiments were carried out by the application of the combined magnetic fields to the solution placed into a Plexiglas reaction vessel at application of static voltage to golden electrodes placed into the solution. Six experiments were carried out by the application of the combined magnetic fields to the solution placed in a Plexiglas reaction vessel, without electrodes, within an electric field, generated by means of a capacitor at the voltage of 27 mV. The frequency of the alternating field was scanned within the bounds of 1.0 Hz including the cyclotron frequency corresponding to a glutamic acid ion and to the applied static magnetic field. In this study the prominent peaks with half-width of ~0.5 Hz and with different heights (till 80 nA) were registered at the alternating magnetic field frequency equal to the cyclotron frequency (4.2 Hz). The general reproducibility of the investigated effects was 70% among the all solutions studied by us and they arose usually after 40–60 min. after preparation of the solution. In some made-up solutions the appearance of instability in the registered current was noted in 30–45 min after the solution preparation. This instability endured for 20–40 min. At the end of such instability period the effects of combined fields action appeared practically every time. The possible mechanisms of revealed effects were discussed on the basis of modern quantum electrodynamics. http://www.biomagres.com/content/6/1/1 Livio Giuliani, Settimio Grimaldi, Antonella Lisi, Enrico D'Emilia, Natalia Bobkova and Mikhail Zhadin BioMagnetic Research and Technology 2008, 6:1 Number of accesses: 213 2008-01-25 doi:10.1186/1477-044X-6-1 BioMagnetic Research and Technology 1477-044X 6 1 2008-01-25 Background: We have developed magnetite cationic liposomes (MCLs) and applied them to local hyperthermia as a mediator. MCLs have a positive charge and generate heat under an alternating magnetic field (AMF) by hysteresis loss. In this study, the effect of hyperthermia using MCLs was examined in an in vivo study of hamster osteosarcoma.MethodMCLs were injected into the osteosarcoma and then subjected to an AMF. Results: The tumor was heated at over 42°C, but other normal tissues were not heated as much. Complete regression was observed in 100% of the treated group hamsters, whereas no regression was observed in the control group hamsters. At day 12, the average tumor volume of the treated hamsters was about 1/1000 of that of the control hamsters. In the treated hamsters, no regrowth of osteosarcomas was observed over a period of 3 months after the complete regression. Conclusion: These results suggest that this treatment is effective for osteosarcoma. http://www.biomagres.com/content/2/1/3 Fumiko Matsuoka, Masashige Shinkai, Hiroyuki Honda, Tadahiko Kubo, Takashi Sugita and Takeshi Kobayashi BioMagnetic Research and Technology 2004, 2:3 Number of accesses: 212 2004-03-25 doi:10.1186/1477-044X-2-3 BioMagnetic Research and Technology 1477-044X 2 3 2004-03-25