Intravenous administration of dextran-ferrite sol was used to amplify T 2 -weighed echo gradient (500/15) scanning MR images with visualization of the invasion margins of tumor cells into healthy tissues, along with macro-and micrometastases, in animals with lymphocytic leukemia and Ehrlich and Lewis carcinomas. Magnetohydrodynamic thermochemotherapy (MTCT) using a cyclophosphamide-containing magnetic fluid (saturation magnetization (M s ) 8.6 kA/m, pH 7.4, ζ + 13 mV) at 46°C for 30 min in an alternating magnetic field (0.88 MHz, 7.2 kA/m, 0.15 kW) with aspiration of necrotic material (ANM) produced regression of P388 tumors of volume ∼110 mm 3 in BDF1 mice prior to metastasis by 40%, with an increase in lifetime (ILT) of 310%; in tumors of volume ∼330 mm 3 after metastasis and MTCT-ANM with cyclophosphamide pretreatment, ILT was 220%.

Dextran-ferrite (DF) sol enhances magnetic-resonance (MR) images obtained by T2-weighted gradient-echo (GRE) (500/15 sequences) scanning with visualization of the boundaries of tumor cell invasion into healthy tissues for macro- and micrometastases of lymphocyte leucosis P388 and the Ehrlich and Lewis carcinomas. After the magnetohydrodynamic thermochemotherapy (MTC) with fluid containing cyclophosphamide (CP) and DF sol (Ms 8.6 kA/m, pH 7.4, ζ + 13 mV) at 46°C for 30 min under AC magnetic field (0.88 MHz, 7.3 kA/m, 0.15 kW) with tumor slime aspiration (TSA), the regression of P388 tumor (~ 110 mm3) in BDF1 mice before metastases was 40% and an increase in the life span (ILS) achieved 310%; for large tumors (~ 330 mm3) after metastases, the MTC-TSA and cyclophosphamide treatment yielded an ILS of 220%.

Смешиванием золей фотогема с золями декстранферрита в воде получили фотогем-содержащие феррижидкости, пригодные для фотогем-магнито-декстранферрит-термосенсибилизации опухолевых клеток. Механизм фотогем-магнито-декстранферрит-термосенсибилизации опухолевых клеток, наиболее вероятно, включает свободнорадикальные процессы.

Ferrimagnetic fluids suitable for magnetothermosensitization (MTS) of tumor cells in ac magnetic field were obtained by mixing photoheme (PH) and dextran ferrite (DF) sols. The mechanisms of the PH + DF-induced MTS most likely involves free-radical processes.

Four series of water-based dextran-ferrite (DF) magnetic fluids (MFs) containing Melphalan (MP) were prepared. Their saturation magnetization (Ms) was from 0.8 to 7.8kA/m; specific power absorption rates were 240W/g Fe. After nine courses of magnetic fluid thermochemotherapy with MP containing DF MF (Ms 7.5kA/m, pH 6.6, ζ+15mV) at 44–46°C for 30min in an AC magnetic field (0.88MHz, 9.3kA/m, 0.3kW), complete P388 tumor regression was seen in 30% of BDF1 mice. Furthermore, a life span increase of 180% was achieved.

Four of the water-based dextran-ferrite (DF) magnetic fluids (MF) were prepared. Their saturation magnetization was from 0.9 to 7.5kA/m; specific power absorption rates were 210W/g Fe; pH was from 6 to 9 and Zeta-potential (ζ) was from +18 to –12mV. After nine magnetic fluid tumor hyperthermia at +44°C to +45°C, 30min with water-filtered AC magnetic field (0.88MHz, 9.3kA/m, 0.15kW), while using DF MF (saturation magnetization 7.5kA/m, pH 6.6, ζ +15mV), a complete tumor regression sarcoma MX11 in C57Bl/6j mice was 33%, life span increase achieved was 150%.

Seventeen different ferromagnetic fluids and suspensions were prepared and evaluated for application in radiofrequency-induced hyperthermia. Specific power absorption rates were measured at 0.88 MHz to range from 0 to 240 W per gram of iron for different preparations. Survival of MX11 cells mixed with ferrofluids and subjected to radiofrequency was much lower than with RF without ferrofluid or ferrofluid alone.

We have developed magnetic dextran-ferrite (DF) nanoparticles [1] and photogem (PG) [2] for tumor cell induction DF AC magnetic field hyperthermia (ACH) [3] and PG magneto- [4] and thermosensitization [5] in the dark (MTS). DF ferrifluids (DFFs), that had been prepared from DF, may be ideal magnetic carriers [1,3,6]. DF dissipatesAC magnetic field energy and therefore causes hyperthermia in the area of their confinement [3]. PG in analogy to hematoporphyrin [4] may generate singlet oxygen or superoxide radicals and cause the destruction of tumor cells in the dark. The inevitable technical problem of photodynamic therapy is the initiation of the absorbency of visible light by a tumor that has been injected with photo-sensitizing agent, because incident light at wavelengths between 600 and 1000 nm reacts with the photosensitizing agent only at shallow depth (0.1-1 cm) of tissue. The purposes ofthis work were: to evaluate PG -containing dextran-ferrite ferrifluidsfor the combination of an ACH with MTS; to analyze the influence of AC magnetic field and hyperthermia on cell death and lysis in the presence of PG; to obtain further insights into themechanisms of these processes.