Study on the thermal field distribution of cholangiocarcinoma model by magnetic fluid hyperthermia / 生物医学工程学杂志

Cholangiocarcinoma is a highly malignant tumor. It is not sensitive to radiotherapy and chemotherapy and has a poor prognosis. At present, there is no effective treatment. As a new method for treating cancer, magnetic fluid hyperthermia has been clinically applied to a variety of cancers in recent years. This article introduces it to the cholangiocarcinoma model and systematically studies the effect of magnetic fluid hyperthermia on cholangiocarcinoma. Starting from the theory of magnetic fluid heating, the electromagnetic and heat transfer models were constructed in the finite element simulation software COMSOL using the Pennes biological heat transfer equation. The Helmholtz coil was used as an alternating magnetic field generating device. The relationship between the magnetic fluid-related properties and the heating power was analyzed according to Rosensweig's theory. After the multiphysics coupling simulation was performed, the electromagnetic field and thermal field distribution in the hyperthermia region were obtained. The results showed that the magnetic field distribution in the treatment area was uniform, and the thermal field distribution met the requirements of hyperthermia. After the magnetic fluid injection, the cholangiocarcinoma tissue warmed up rapidly, and the temperature of tumor tissues could reach above 42 °C, but the surrounding healthy tissues did not heat up significantly. At the same time, it was verified that the large blood vessels around the bile duct, the overflow of the magnetic fluid, and the eddy current heat had little effect on thermotherapy. The results of this article can provide a reference for the clinical application of magnetic fluid hyperthermia for cholangiocarcinoma.

Simulation of the relationship between magnetic medium parameters and heating temperature in magnetic fluid hyperthermia / 生物医学工程学杂志

In this paper, we established magnetic fluid hyperthermia (MFH) model for rat tumor using the finite element software COMSOL based on the linear response theory. By analyzing four kinds of magnetic medium within relaxation mechanism, such as Fe O 、FeCo、fccFePt and L1 FePt, we studied the influence of the change of magnetic medium radius on dissipation power and temperature field, respectively. At the same time, the optimization method for the parameters of several magnetic medium is proposed, and the applications of four kinds of magnetic medium are given as well. By increasing the dissipation power of the magnetic medium as much as possible, the dose of magnetic medium used in the treatment can be reduced, meanwhile, the adverse effects on health tissue surrounding the tumor will be minimized. The conclusions of this paper can provide reference for magnetic medium preparation applied to MFH.

Therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia using Fe2O3 nanoparticles

This study aimed to investigate the therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia (MFH) using Fe2O3 nanoparticles. Hepatocarcinoma SMMC-7721 cells cultured in vitro were treated with ferrofluid containing Fe2O3 nanoparticles and irradiated with an alternating radio frequency magnetic field. The influence of the treatment on the cells was examined by inverted microscopy, MTT and flow cytometry. To study the therapeutic mechanism of the Fe2O3 MFH, Hsp70, Bax, Bcl-2 and p53 were detected by immunocytochemistry and reverse transcription polymerase chain reaction (RT-PCR). It was shown that Fe2O3 MFH could cause cellular necrosis, induce cellular apoptosis, and significantly inhibit cellular growth, all of which appeared to be dependent on the concentration of the Fe2O3 nanoparticles. Immunocytochemistry results showed that MFH could induce high expression of Hsp70 and Bax, decrease the expression of mutant p53, and had little effect on Bcl-2. RT-PCR indicated that Hsp70 expression was high in the early stage of MFH (<24 h) and became low or absent after 24 h of MFH treatment. It can be concluded that Fe2O3 MFH significantly inhibited the proliferation of in vitro cultured liver cancer cells (SMMC-7721), induced cell apoptosis and arrested the cell cycle at the G2/M phase. Fe2O3 MFH can induce high Hsp70 expression at an early stage, enhance the expression of Bax, and decrease the expression of mutant p53, which promotes the apoptosis of tumor cells.

Establishment and characterization of a targeting tumor vesseles system for inducing thrombosis / 中国药学杂志

METHODS: Chemical cross-linking technique was used to prepare a cross-linking agent of the A6-Streptavidin (A6-SA), MF-A6-SA and Biotein-tTF (B-tTF). FX coagulation assay was used to test MF-A6-SA:B-tTF system's FX activity. Fluorescence microscopy and prussian blue staining were used to simultaneously observe the targeting activity of MF-A6-SA:B-tTF with an external magnetic field. Hemagglutination was directly used to study the system's biological amplification by SA/B. Biodistribution experiment was used to observe the toxicity of MF-A6-SA:B-tTF.

Amphotericin B: an antifungal drug in nanoformulations for the treatment of paracoccidioidomycosis / La anfotericina B: una droga antifúngica en nanoformulaciones para el tratamiento de la paracoccidioidomicosis

The use of magnetic nanoparticles (MNPs) in drug delivery vehicles must address issues such as drugloading capacity, desired release profile, aqueous dispersion stability, biocompatibility with cells and tissue, and retention of magnetic properties after interaction with macromolecules or modification via chemical reactions. Amphotericin B (AmB) is still the first choice for the treatment of severe paracoccidioidomycosis, an important systemic fungal infection caused by Paracoccidoides brasiliensis. Unfortunately, AmB causes acute side effects (mainly urinary problems) following intravenous administration, which limits its clinical use. The use of magnetic nanoparticles stabilized with biocompatible substances, together with the possibility of their conjugation with drugs has become a new nanotechnological strategy in the treatment of diseases for drug delivery to specific locations, such as the lungs in paracoccidoidiodomycosis. This review provides an overview of the disease, its etiologic agent and treatment with emphasis on the main strategies to improve the use of AmB in nanoformulations.

El uso de nanopartículas magnéticas (MNPS) en los vehículos de suministro de fármacos debe abordar cuestiones como la capacidad de carga de las drogas, el perfil deseado de liberación, estabilidad de la dispersión acuosa, biocompatibilidad con las células, tejidos y la conservación o la modificación de las propiedades magnéticas después de la interacción con macromoléculas y/o reacciones químicas. La anfotericina B (AnB) continua siendo la primera opción para el tratamiento de la paracoccidioidomicosis grave, una importante infección sistémica causada por el hongo Paracoccidioides brasiliensis. Sin embargo, la AnB causa efectos secundarios agudos (principalmente problemas urinarios) tras la administración intravenosa, limitando su uso clínico. El uso de nanopartículas magnéticas estabilizadas con sustancias biocompatibles y conjugadas con fármacos, se ha convertido en una nueva estrategia nanotecnológica para el tratamiento de enfermedades en sitios específicos, como los pulmones en paracoccidoidiodomycosis. En esta revisión se hace una descripción general de la enfermedad, su agente etiológico y su tratamiento con énfasis en la principales estrategias para mejorar el uso de AnB en nanoformulaciones.

Systhesis of magnetic thermosensitive hydrogel and its heat effect under alternating magnetic field / 中国药学杂志

OBJECTIVE: To synthesize magnetic thermosensitive hydrogel and study its heat effect under alternating magnetic field in vitro. METHODS: PLGA-PEG-PLGA triblock copolymer was synthesized by ring-opening polymerization of D, L-lactide and glycolide with PEG1500 in the presence of stannous iso caprylate. Magnetic thermosensitive hydrogel of different concentrations were prepared using different currents. The influences of the concentration of magnetic fluid and current of magnetic field on the heat effect were separately observed. RESULTS: The synthetized PLGA-PEG-PLGA triblock copolymer was excellently temperature sensitive. It retained the thermo-sensitivity of original hydrogel when the magnetic fluid was loaded. The 5, 10 and 20 min heating ability of magnetic fluid was positively linearly correlated with its concentration (r=0.9985, 0.9893 and 0.9711, respectively, n=3) and current of magnetic field (r=0.9948, 0.9977 and 0.9994, respectively, n=4). CONCLUSION: The magnetic thermosensitive hydrogel has excellent temperature sensitivity. When alternating magnetic field is applied, the temperature of the system can rise and reach above LCST of hydrogel. The temperature can be controlled by changing the concentration of magnetic fluid and the current of magnetic field. Copyright 2012 by the Chinese Pharmaceutical Association.

Experimental study of treatment on rabbit liver VX2 tumor by selective hepatic artery embolization hyperthermia with nano superparamagnetic iodized oil / 中华放射学杂志

Objective To observe the therapeutic response of liver tumors by arterial embolization hyperthermia with Nano Superparamagnetic Iodized Oil(NSIO)using rabbit VX2 liver tumor model.Methods A total 24 rabbits containing experimental hepatic tumors were randomly assigned to one of four groups as follows:NSIO embolization hyperthermia group(group A),Lipidol embolization group(group B),NSIO embolization group(group C),and contronl group(group D),each groups contain 6 VX2 rabbits.Fourteen days after implantation of the experimental hepatic tumor,VX2 rabbits were treated.In group A group B and group C,the rabbits hepatic proper artery were selectively catheterized by 3 Fr microcatheters via right femoral artery under fluoroscopic guidance.10% NSIO 0.5 ml(group A and group C)or Lipidol 0.5 ml(group B)infused into proper hepatic artery.Three days after embolization,the rabbits in group A and group B were exposed to gap-type alternating magnetic field for 30 minutes,while rabbits in group C and group D have not been exposed to alternating magnetic field.The liver tumor size were measured by CT scanning before and 14 days after treatment then the animals were sacrificed,the liver,lung,heart spleen and kidney were harvested for histopathology examination,the liver tumor size were detected directly. Results All subjects experienced uneventful 14 days surivials,on the biochemical examination,there were no changes about the function of liver and renal in each group 14 days after treatment compare to pre- treatment.Fourteen days after treatment,the tumor size decreased by 8.09% in group A,but increased by 9.72% and 13.00%(P＜0.05)in group B and group C respectively,in group D,the tumor size increased by 57.50%(P＜0.01).In histopathology examination,the tumor necrosis in three treatment groups were manifest,particular in group A.Conclusion Arterial embolization hyperthermia with NSIO has obvious therapeutic response to experimental hepatic tumors,it encourages further development of this technology for the treatment of liver cancer in humans.