Background: In magnetic drug targeting (MDT), micro- or nanoparticles are injected into the human body to locally deliver therapeutics. These magnetic particles can be guided from a distance by external magnetic fields and gradients from electromagnets.
Purpose: During the particles' movement through the vascular network, they are affected by magnetic forces, fluid (drag) forces, particle interactions, diffusion, etc.
Local-regional administration of cytotoxic drugs is an important adjunct to systemic chemotherapy amongst cancer patients. It allows for targeted delivery of agents at high concentration to target sites while minimizing systemic side effects. Despite the pharmacokinetic advantages of the local-regional approach, drug transport into tumor nodules remains limited due to the biophysical properties of these tissues.
View Article and Find Full Text PDFMagnetorelaxometry imaging (MRXI) is an experimental imaging technique applicable for noninvasive, qualitative and quantitative imaging of magnetic nanoparticles (MNPs). Accurate reconstructions of nanoparticle distributions are crucial for several novel treatment methods employing MNPs such as magnetic drug targeting or magnetic hyperthermia therapy. Hence, it is desirable to design MRXI setups such that the reconstruction accuracy is maximized for a given set of design parameters.
View Article and Find Full Text PDFMagnetic nanoparticles are an important asset in many biomedical applications ranging from the local heating of tumours to targeted drug delivery towards diseased sites. Recently, magnetic nanoflowers showed a remarkable heating performance in hyperthermia experiments thanks to their complex structure leading to a broad range of magnetic dynamics. To grasp their full potential and to better understand the origin of this unexpected heating performance, we propose the use of Kaczmarz' algorithm in interpreting magnetic characterisation measurements.
View Article and Find Full Text PDFMagnetic drug targeting (MDT) is an application in the field of targeted drug delivery in which magnetic (nano)particles act as drug carriers. The particles can be steered toward specific regions in the human body by adapting the currents of external (electro)magnets. Accurate models of particle movement and control algorithms for the electromagnet currents are two of the many requirements to ensure effective drug targeting.
View Article and Find Full Text PDFA subset of patients with Covid-19 presents with negative RT-PCR screening but suspect CT findings. Using four commercially available anti-SARS-CoV-2 IgG immuno-assays, we found this subset constituted 9.2% of all consecutively admitted outpatients with Covid-19 in our hospital.
View Article and Find Full Text PDFMagnetic nanoparticles are increasingly employed in biomedical applications such as disease detection and tumor treatment. To ensure a safe and efficient operation of these applications, a noninvasive and accurate characterization of the particles is required. In this work, a magnetic characterization technique is presented in which the particles are excited by specific pulsed time-varying magnetic fields.
View Article and Find Full Text PDFInfect Control Hosp Epidemiol
November 2020
Magnetic nanoparticles exposed to alternating magnetic fields have shown a great potential acting as magnetic hyperthermia mediators for cancer treatment. However, a dramatic and unexplained reduction of the nanoparticle magnetic heating efficiency has been evidenced when nanoparticles are located inside cells or tissues. Recent studies suggest the enhancement of nanoparticle clustering and/or immobilization after interaction with cells as possible causes, although a quantitative description of the influence of biological matrices on the magnetic response of magnetic nanoparticles under AC magnetic fields is still lacking.
View Article and Find Full Text PDFMagnetorelaxometry (MRX) is a well-known measurement technique which allows the retrieval of magnetic nanoparticle (MNP) characteristics such as size distribution and clustering behavior. This technique also enables the non-invasive reconstruction of the spatial MNP distribution by solving an inverse problem, referred to as MRX imaging. Although MRX allows the imaging of a broad range of MNP types, little research has been done on imaging different MNP types simultaneously.
View Article and Find Full Text PDFPurpose: The performance of an increasing number of biomedical applications is dependent on the accurate knowledge of the spatial magnetic nanoparticle (MNP) distribution in the body. Magnetorelaxometry (MRX) imaging is a promising and noninvasive technique for the reconstruction of this distribution. To date, no accurate and quantitative measure is available to compare and optimize different MRX imaging models and setups independent of the MNP distribution.
View Article and Find Full Text PDFPurpose: Magnetic nanoparticles (MNPs) are an important asset in many biomedical applications. An effective working of these applications requires an accurate knowledge of the spatial MNP distribution. A promising, noninvasive, and sensitive technique to visualize MNP distributions in vivo is electron paramagnetic resonance (EPR).
View Article and Find Full Text PDFElectron paramagnetic resonance (EPR) is a sensitive measurement technique which can be used to recover the 1-D spatial distribution of magnetic nanoparticles (MNP) noninvasively. This can be achieved by solving an inverse problem that requires a numerical model for interpreting the EPR measurement data. This paper assesses the robustness of this technique by including different types of errors such as setup errors, measurement errors, and sample positioning errors in the numerical model.
View Article and Find Full Text PDFWe present Vinamax, a simulation tool for nanoparticles that aims at simulating magnetization dynamics on very large timescales. To this end, each individual nanoparticle is approximated by a macrospin. Vinamax numerically solves the Landau-Lifshitz equation by adopting a dipole approximation method, while temperature effects can be taken into account with two stochastic methods.
View Article and Find Full Text PDFObjectives: To compare the validity of parent-reported height, weight and body mass index (BMI) values of children (aged 4-10 years), when measured at home by means of newly developed instruction leaflets in comparison with simple estimated parental reports.
Design: Randomised controlled trial with control and intervention group using simple randomisation.
Setting: Belgian children and their parents recruited via schools (multistage cluster sampling design).
Congenital bilateral perisylvian polymicrogyria (CBPP) is the most frequent type of polymicrogyria in children. A 3-month-old male patient is described here with the combination of CBPP, infantile spasms and arthrogryposis. Only four patients have been reported earlier in the literature with this combination.
View Article and Find Full Text PDFAm J Respir Crit Care Med
May 1996
Peroxynitrite (ONOO-) is a cytotoxic product of the rapid reaction between nitric oxide and superoxide that may initiate inflammation. Isolated perfused tracheas from guinea pigs were incubated from the mucosal side for 15 min with peroxynitrite (1 to 100 muM). Thereafter, concentration-response curves to histamine and methacholine were constructed on the preparations.
View Article and Find Full Text PDFThe use of granulocyte transfusions during amphotericin B treatment of invasive fungal infections in granulocytopenic patients is controversial because of concern about pulmonary complications from leukostasis. Moreover, the administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) to patients with active infections has been questioned because of reports that this cytokine inhibits neutrophil migration into areas of inflammation. We report a case in which the combined use of amphotericin B, granulocyte transfusions, and GM-CSF was safe and life-saving in a pancytopenic patient with disseminated fusarium infection.
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