Репозиторий Университета

© 2020 Elsevier B.V. Magnetic hyperthermia (MH) is a perspective tool to treat the tumor while the magnetic material is delivered. The key problems in MH development is to ensure an effective local heating within cancer cell without overheating other cells. In order to do that one has to reach substantial local accumulation of magnetic nanoparticles (MNPs) and/or magnetically sensitive objects with advanced heat properties. Absorbing heat energy for destroying tumor cells can be generated only if there is sufficient amount of locally placed MNPs. In this work, we propose polyelectrolyte microcapsules modified with iron oxide nanoparticles as an approach to tie magnetic materials in high concentration locally. These microcapsules (about 3 microns in diameter) can be readily internalized by various cells. The human fibroblasts uptake of the microcapsules and cytotoxic effect upon the influence of alternating magnetic field (AMF) while magnetic capsules are inside the cells is under study in this work. The cytotoxicity of the magnetic microcapsules was compared with the cytotoxicity of the MNPs while free in the solution to evaluate the effect of bounding MNPs. A cytotoxic effect on cells was found in the case of preliminary incubation of fibroblasts with capsules while the AMF is applied. In the case of MNPs in an equivalent dose per mass of magnetic material, there was no cytotoxic effect noticed after the treatment with the field. It is noteworthy that during the treatment of cells with the AMF, the increase in temperature of the incubation medium was not registered. The morphological changes on fibroblasts were consistent with the data of the viability assessment. Thus, the synthesized capsules are shown as a means for local enhancement of magnetic hyperthermia in the treatment of tumor diseases.

It is known that the reduction of blood vessels by epinephrine that are part of the local anesthetic leads to a decrease in oxygen intake and the development of hypoxia, which has a significant effect on the excitability of nerve fibers. This is due to the fact that epinephrine is present in the local anesthetic cartridge, which helps to reduce, until termination, microcirculation in the depot area, which leads to local hypothermia. With the introduction of local anesthetics, the temperature of which is significantly lower than the depot temperature, the patient experiences severe discomfort, which is associated with unsuccessful local anesthesia. The goal of the study was the need to analyze the feasibility of using the thermography method in assessing the degree of ischemia of the soft tissues of the maxillofacial region against the background of local anesthesia with a different concentration of epinephrine in dentistry. MATERIAL AND METHODS: In the pilot study, 22 healthy volunteers aged between 29-35 years of both sexes participated. To assess the degree of external vasoconstriction, a buccal region was chosen near the maxilla. Infiltration anesthesia was used with a 4% solution of articaine with epinephrine 1: 100 000 and 1: 200 000 at a dosage of 0.5-0.7 ml. The temperature distribution in the study area was estimated using a thermal imager Nec InfReC Thermo Gear G30. RESULTS: The study showed that the use of epinephrine in local anesthetics naturally has a moderate effect on hemodynamics in areas adjacent to the anesthesia depot. When using a low concentration of epinephrine (1:200 000), the projection hyperthermia of the skin is determined. Perhaps this is due to the activation of microcirculation due to an increase in capillary blood flow in the region above the zone of action of the epinephrine. From the point of view of physiological arterial hyperemia, this mechanism carries positive properties, since leads to an increase in tissue oxygenation. When using a high concentration of epinephrine (1:100 000), the zone of hypothermia of the skin is determined, which corresponds to the phenomenon of angiospastic ischemia.

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. In this paper, we demonstrate instruments for laser radiation delivery based on sapphire capillary needles. Such sapphire irradiators (introducers) can be used for various medical applications, such as photodynamic therapy, laser hyperthermia, laser interstitial thermal therapy, and ablation of tumors of various organs. Unique properties of sapphire allow for effective redistribution of the heat, generated in biological tissues during their exposure to laser radiation. This leads to homogeneous distribution of the laser irradiation around the needle, and lower possibility of formation of the overheating focuses, as well as the following non-transparent thrombi.

The TRPV1 receptor plays a significant role in many biological processes, such as perception of external temperature (above 43°C), inflammation development, and thermoregulation. Activation of TRPV1 leads to the pain occurrence and decrease in the body temperature, while inhibition of this receptor can lead to an increase in the temperature. The TRPV1 peptide modulators from sea anemone Heteractis crispa extract (APHC1 and APHC3) have been previously characterized as molecules, which generated a pronounced analgesic effect and a decrease in the body temperature in experimental animals. Using the combined APHC1 and APHC3 amino acid sequences, we have prepared a hybrid peptide molecule named A13 that contains all residues potentially important for the activity of the peptide precursors. Biological tests on animals have shown that the hybrid molecule not only combines the analgesic properties of both peptides but, unlike the peptide precursors, also raises the body temperature of experimental animals.

The TRPV1 receptor plays a significant role in many biological processes, such as perception of external temperature (above 43°C), inflammation development, and thermoregulation. Activation of TRPV1 leads to the pain occurrence and decrease in the body temperature, while inhibition of this receptor can lead to an increase in the temperature. The TRPV1 peptide modulators from sea anemone Heteractis crispa extract (APHC1 and APHC3) have been previously characterized as molecules, which generated a pronounced analgesic effect and a decrease in the body temperature in experimental animals. Using the combined APHC1 and APHC3 amino acid sequences, we have prepared a hybrid peptide molecule named A13 that contains all residues potentially important for the activity of the peptide precursors. Biological tests on animals have shown that the hybrid molecule not only combines the analgesic properties of both peptides but, unlike the peptide precursors, also raises the body temperature of experimental animals.