THz radiation is increasingly used for diagnostics in medicine. As technology utilizing THz radiation continues to develop rapidly, it is becoming increasingly important to consider its biological effects and establish safe exposure standards and parameters. The paper presents data on the clinical status and functional properties of the anterior and posterior structures of the eyes of rabbits after THz irradiation at the frequency of 2.3 THz. Terahertz radiation was generated at Novosibirsk Free Electron Laser (NovoFEL) at “Siberian Synchrotron and Terahertz Radiation Centre” (Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia). The exposure durations used were 15 and 30 minutes. Intensity ranges were I1=0.012 mW/cm2, I2=0.018 mW/cm2, and I3=0.024 mW/cm2. The study investigated the effects of various time and power irradiation protocols on the California rabbit’s eyes and after a period of one month, but no significant clinical or functional alterations were observed in response to the established intensity protocols. However, the study identified statistically significant changes in corneal hydration and endothelial cell density over time, particularly under protocols with 15- and 30-minute exposures. A negative correlation was found between endothelial cell density and corneal thickness (r=-0.36, p=0.042), suggesting that a reduction in the endothelial cell pool may be associated with increased corneal thickness. These changes were subclinical and did not lead to clinically significant pathological changes in the cornea. There were no signs of ASOCT (anterior segment-optical coherence tomography) hyperreflectivity. THz radiation with parameters listed above of 2.3 THz and an intensities of 0.012-0.024 mW/cm2 for 30 minutes has been shown to be conditionally safe for the structures of the rabbit eye. However, the detected subclinical corneal changes require further study to determine safe exposure limits.

An approach to quantify boron in cells after administration of boron nanoparticles (BNPs) stabilized in hydroxyethyl cellulose (HEC) was developed. In vitro experiments with human glioblastoma cells and BNPs stabilized in HEC were carried out. Cell samples with BNPs were dried on graphite powder under an infrared lamp and analyzed by direct current arc atomic emission spectrometry (DCA AES).

We conducted a clinical veterinary study on neutron capture therapy (NCT) at a neutron-producing accelerator with seven incurable pets with spontaneous tumors and gadolinium as a neutron capture agent (gadolinium neutron capture therapy, or GdNCT). Gadolinium-containing dimeglumine gadopentetate, or Gd-DTPA (Magnevist®, 0.6 mL/kg b.w.), was used. We observed mild and reversible toxicity related to the treatment. However, no significant tumor regression in response to the treatment was observed. In most cases, there was continued tumor growth. Overall clinical improvement after treatment was only temporary. The use of Gd-DTPA for NCT had no significant effects on the life expectancy and quality of life of animals with spontaneous tumors. Further experiments using more advanced gadolinium compounds are needed to improve the effect of GdNCT so that it can become an alternative to boron neutron capture therapy. Such studies are also necessary for further NCT implementation in clinical practice as well as in veterinary medicine.

Boron neutron capture therapy is considered a promising method for the treatment of malignant tumors of the head and neck. It is believed that to increase the effectiveness of this type of therapy, the use of large doses of boron is required, which may entail damaging effects on healthy tissue. One of the substances used in the clinical practice of boron neutron capture therapy is sodium boroncaptate Na 2 B 12 H 11 SH (BSH), enriched with the 10B boron isotope. The purpose of the study was to study the structural reactions of the myocardium and liver of CD-1 mice after administration of BSH. A light-optical and polarization-microscopic study of the myocardium and liver of male CD-1 mice (n=56) was carried out after injection of a boron-containing substance in doses of 100 and 1000 mg/kg, once, intraperitoneally. Assessment of structural changes in the myocardium and liver was carried out 1, 3 and 7 days after BSH administration. A single injection of BSH at a dose of 100 mg/kg did not lead to the death of animals, whereas 3 hours after the injection of BSH at a dose of 1000 mg/kg, 1 animal died. The body weight of the animals changed slightly during the experiment. Analysis of heart weight showed a decrease in this indicator on days 3 and 7 compared with indicators in the same groups on day 1 of the experiment. When analyzing the dynamics of changes in liver mass, no significant changes were revealed during the experiment. The main structural changes in the myocardium included lytic and contractural damage to cardiomyocytes, hemodynamic disturbances in the form of pronounced venous and capillary congestion. Liver damage was manifested in dystrophic changes in hepatocytes, the appearance after 3 days of monocellular necrosis of hepatocytes and pericentral mononuclear infiltrates. The data obtained indicate that the used doses of BSH 100 and 1000 mg/kg with a single injection cause structural changes in the myocardium and liver of varying severity, which persist for 7 days of observation.

The novel conjugates of cholesterol with cobalt – bis(dicarbollide) were synthesized by the ring-opening reactions of the cyclic oxonium derivatives of [3,3′-Co(C2B9H11)2]– with the OH group of cholesterol 2-hydroxyethyl ether. The compounds obtained were tested for toxicity to glioblastoma U-87 MG cells and human embryo fibroblasts FECH-15 cells

(1) Background: accelerator-based neutron sources are a new frontier for BNCT but many technical issues remain. We aimed to study such issues and results in larger-animal BNCT (cats and dogs) with naturally occurring, malignant tumors in different locations as an intermediate step in translating current research into clinical practice. (2) Methods: 10 pet cats and dogs with incurable, malignant tumors that had no treatment alternatives were included in this study. A tandem accelerator with vacuum insulation was used as a neutron source. As a boron-containing agent, 10B-enriched sodium borocaptate (BSH) was used at a dose of 100 mg/kg. Animal condition as well as tumor progression/regression were monitored. (3) Results: regression of tumors in response to treatment, improvements in the overall clinical picture, and an increase in the estimated duration and quality of life were observed. Treatment-related toxicity was mild and reversible. (4) Conclusions: our study contributes to preparations for human BNCT clinical trials and suggests utility for veterinary oncology.

Boron neutron capture therapy (BNCT) can become an instrument for patients with malignant neoplasms of the rectum and colon. Here we evaluate the effectiveness of BNCT performed at the accelerator based epithermal neutron source at G. I. Budker Institute of Nuclear Physics, Siberian Division of Russian Academy of Sciences, in relation to subcutaneous xenografts of human colon adenocarcinoma SW-620 in SCID mice. Utilization of BNCT with boronоphenylalanine (BPA) and sodium borocaptate (BSH), which were injected intravenously into the retroorbital sinus, resulted in a significant decrease in tumor volumes compared to the control group (no radiation).

Sufficient boron-10 isotope (10B) accumulation by tumor cells is one of the main requirements for successful boron neutron capture therapy (BNCT). The inability of the clinically registered 10B-containing borophenylalanine (BPA) to maintain a high boron tumor concentration during neutron irradiation after a single injection has been partially solved by its continuous infusion; however, its lack of persistence has driven the development of new compounds that overcome the imperfections of BPA. We propose using elemental boron nanoparticles (eBNPs) synthesized by cascade ultrasonic dispersion and destruction of elemental boron microparticles and stabilized with hydroxyethylcellulose (HEC) as a core component of a novel boron drug for BNCT. These HEC particles are stable in aqueous media and show no apparent influence on U251, U87, and T98G human glioma cell proliferation without neutron beam irradiation. In BNCT experiments, cells incubated with eBNPs or BPA at an equivalent concentration of 40 µg 10B/mL for 24 h or control cells without boron were irradiated at an accelerator-based neutron source with a total fluence of thermal and epithermal neutrons of 2.685, 5.370, or 8.055 × 1012/cm2. The eBNPs significantly reduced colony-forming capacity in all studied cells during BNCT compared to BPA, verified by cell-survival curves fit to the linear-quadratic model and calculated radiobiological parameters, though the effect of both compounds differed depending on the cell line. The results of our study warrant further tumor targeting-oriented modifications of synthesized nanoparticles and subsequent in vivo BNCT experiments.

Boron neutron capture therapy (BNCT) is an anticancer modality realized through 10B accumulation in tumor cells, neutron irradiation of the tumor, and decay of boron atoms with the release of alpha-particles and lithium nuclei that damage tumor cell DNA. As high-LET particle release takes place inside tumor cells absorbed dose calculations are difficult, since no essential extracellular energy is emitted. We placed gold nanoparticles inside tumor cells saturated with boron to more accurately measure the absorbed dose. T98G cells accumulated ~50 nm gold nanoparticles (AuNPs, 50 µg gold/mL) and boron-phenylalanine (BPA, 10, 20, 40 µg boron-10/mL), and were irradiated with a neutron flux of 3 × 108 cm−2s−1. Gamma-rays (411 keV) emitted by AuNPs in the cells were measured by a spectrometer and the absorbed dose was calculated using the formula D = (k × N × n)/m, where D was the absorbed dose (GyE), k—depth-related irradiation coefficient, N—number of activated gold atoms, n—boron concentration (ppm), and m—the mass of gold (g). Cell survival curves were fit to the linear-quadratic (LQ) model. We found no influence from the presence of the AuNPs on BNCT efficiency. Our approach will lead to further development of combined boron and high-Z element-containing compounds, and to further adaptation of isotope scanning for BNCT dosimetry.

According to the World Health Organization, colorectal cancer is one of the three leading causes of death among other tumors. Boron neutron capture therapy (BNCT) is a promising method for the treatment of oncological diseases. It is an experimental method of radiation therapy which is based on the capture reaction of a thermal neutron by an isotope B-10 and results in the B-10(n, alpha)Li-7 fission reaction. The high linear energy transfer from alpha particle and Li-7 nucleus has a short path length, thus the energy released is limited to the size of one cell. Previously, BNCT was actively used to treat patients with glioblastoma, melanoma, head and neck cancer, and other malignant neoplasms of various localization. The aim of this work is to determine the safe concentrations of boronphenylalanine (BPA) and sodium borocaptate (BSH) drugs for the SW-620 cell line and to assess the B-10 biodistribution after administration of these compaunds to immunodeficient SCID mice with heterotopic SW-620 xenografts. To evaluate the possibility of using BNCT as a therapy for patients with colorectal cancer, we carried out preliminary in vitro and in vivo studies on the model of human colorectal adenocarcinoma SW-620. Firstly, the cytotoxicity of boron compounds BPA and BSH at B-10 concentrations of 10-1280 mu g/ml was investigated using MTT test. All animal experiments were conducted in accordance with the principles of humane treatment of animals in compliance with the directive of the European Community (86/609 / EEC) and correspond to the principles of the Guide for the Care and Use of Laboratory Animals (NIH USA, No 85-23, rev. 1985). To determine the toxicity of BPA and BSH in standard dosages, drugs were intravenously injected into the retroorbital sinus: BPA at a concentration of 350 mg/kg and BSH at 100 mg/kg. The control group of animals were injected intravenously with sodium chloride 0.9%. After 2 months of observation planned euthanasia was done, organs (kidneys, liver, lungs, brain and heart) were sampled for pathomorphological study. Biodistribution of B-10 in the tumor and organs of interest was performed on mice with SW-620 heterotopic xenograft. Boron containing drugs were injected at the dosages described earlier intravenously into the retroorbital sinus. Euthanasia was performed 1, 2, 3, and 4 hours after injection, tumor tissue, blood, brain, liver and kidneys were sampled. The boron concentration was analyzed by inductively coupled plasma atomic emission spectrometry (ICP AES). As a result of the MTT test, we revealed that incubation of SW-620 cells with BPA and BSH for 24 and 48 hours at B-10 concentrations of 10-320 mu g/ml had no cytotoxic effect. When incubated for 48 hours with BPA at a concentration of 320 mu g/ml, survival rate did not differ significantly from control. The maximum safe concentration for BSH can also be considered 320 mu g/ml of B-10, since the cell survival in the experimental groups was 96 and 95.5% for 24 and 48 hours of incubation with the drug, respectively. The first significant cytotoxic effects were noted during incubation with both boron-containing drugs at a B-10 concentration of 640 mu g/ml. For the BPA group, the percentage of survived cells was 65 (incubation for 24 hours) and 51 (48 hours), BSH had less cytotoxic effect: cell survival decreased to 87% and 80.5% at points 24 and 48 hours, respectively (See Fig. 1). Intravenous administration of BPA at a concentration of 350 mg/kg and BSH at a concentration of 100 mg/kg to SCID mice turned out to be safe: no pathological reactions were detected within 2 months of observation, all animals were alive. According to the pathomorphological study, no macroscopic and structural changes in the organs were found (See Fig. 2). The biodistribution of B-10 was assessed in SCID mice with subcutaneous xenografts SW-620 after intravenous administration of boron drugs at standard concentrations. As a result of the analysis, we found out that after intravenous administration of BPA at a safe dosage, the maximum concentration of B-10 in the tumor was recorded at the time points of 1 and 2 hours (8.0 and 8.7 mu g/g, respectively). In this case, the concentration ratio of B-10 in the tumor and blood samples was determined as 0.6 for the 1 hour point and 1.7 for the 2 hour point. We also demonstrated that the kidneys were the organ with the highest boron accumulation throughout the experiment (See Fig. 3). Thus, the time point of 2 hours can be considered potentially the most suitable for BNCT, but the concentration of boron in the tumor tissue is not sufficient. For BSH the maximum concentration was recorded at the time point of 1 hour (5.7 mu g/g). The liver, kidneys and blood contained the highest concentration of B-10 (See Fig. 4). Thus, apparently, further investigations on increasing the dose of the drugs and choosing different ways of boron agents administration can increase the accumulation of B-10 by the tumor and reduce its concentration in the surrounding tissues and blood. The use of additional drugs that improve the penetration of boron into the tumor may also be effective and should be taken into account.

48-56 ОЦЕНКА ЭФФЕКТИВНОСТИ БОР-НЕЙТРОНОЗАХВАТНОЙ ТЕРАПИИ НА ГЕТЕРОТОПИЧЕСКОЙ МОДЕЛИ ГЛИОБЛАСТОМЫ U87 У ИММУНОДЕФИЦИТНЫХ МЫШЕЙ ЛИНИИ SCID Кривошапкин А.Л. 1 , Каныгин В.В. 1 , Касатова А.И. 2 , Сёмин П.А. 3 , Кичигин А.И. 2 , Разумов И.А. 4 , Соловьева О.И. 4 , Завьялов Е

Introduction. Boron neutron capture therapy (bnct) is a promising method for treating tumors, in particular, infiltrative malignant tumors, due to the selective destruction of tumor cells without damaging the surrounding normal tissues. This type of therapy is based on nuclear reaction of neutron capture by stable 10b isotope. For the successful implementation of bnct, boron delivery drugs that must be selectively accumulated in malignant cells in a sufficient amount, and a neutron source with the energy required for the neutron capture reaction are needed. At the budker institute of nuclear physics, the accelerator-based neutron source was designed with flux parameters allowing studies on bnct to be conducted. Objective: to assess the effect of bnct on tumor and normal cell lines using borphenylalanine (bpa), borcaptate (bsh) and liposomal borcaptat as boron delivery drugs. Materials and methods. Human cell cultures: glioblastoma (u87), colorectal human adenocarcinoma (sw-620), human melanoma (sk-mel28) and primary embryonic cell lines were irradiated with a neutron flux at the presence of bpa, bsh and liposomal bsh with a concentration of 10b 40 μg/ml. The short-term cytotoxic effect of irradiation was evaluated using trypan blue. Cell survival 96 hours after irradiation was determined using mtt test, and survival fraction was evaluated using the clonogenic test. Results. Early cytotoxic effects of irradiation were not observed for all 4 cell lines. According to mtt and clonogenic tests, the most pronounced effect of bnct was noticed for sw-620 and u87 lines, regardless of boron delivery drug used. For sk-mel28 line, the best effect was achieved after irradiation with liposomal borocaptate. For the primary transplanted embryonic line, high toxicity was revealed when bnct was performed with borphenylalanine and borcaptate. Conclusion. The data obtained indicate that the accelerator-based bnct using boron delivery drugs, such as borphenylalanine, borcaptate and liposomal borcaptat, has a positive effect on tumor lines of glioblastoma, colorectal adenocarcinoma and melanoma.

(1) Background: Developments in accelerator-based neutron sources moved boron neutron capture therapy (BNCT) to the next phase, where new neutron radiation parameters had to be studied for the treatment of cancers, including brain tumors. We aimed to further improve accelerator-BNCT efficacy by optimizing dosimetry control, beam parameters, and combinations of boronophenylalanine (BPA) and sodium borocaptate (BSH) administration in U87MG xenograft-bearing immunodeficient mice with two different tumor locations. (2) Methods: The study included two sets of experiments. In Experiment #1, BPA only and single or double irradiation in higher doses were used, while, in Experiment #2, BPA and BSH combinations and single or double irradiation with dosage adjustment were analyzed. Mice without treatment or irradiation after BPA or BPA+BSH injection were used as controls. (3) Results: Irradiation parameter adjustment and BPA and BSH combination led to 80–83% tumor-growth inhibition index scores, irradiation:BNCT ratios of 1:2, and increases in animal life expectancy from 9 to 107 days. (4) Conclusions: Adjustments in dosimetry control, calculation of irradiation doses, and combined use of two 10B compounds allowed for BNCT optimization that will be useful in the development of clinical-trial protocols for accelerator-based BNCT.

Introduction. Boron neutron capture therapy (bnct) is a promising method for treating tumors, in particular, infiltrative malignant tumors, due to the selective destruction of tumor cells without damaging the surrounding normal tissues. This type of therapy is based on nuclear reaction of neutron capture by stable 10b isotope. For the successful implementation of bnct, boron delivery drugs that must be selectively accumulated in malignant cells in a sufficient amount, and a neutron source with the energy required for the neutron capture reaction are needed. At the budker institute of nuclear physics, the accelerator-based neutron source was designed with flux parameters allowing studies on bnct to be conducted.Objective: to assess the effect of bnct on tumor and normal cell lines using borphenylalanine (bpa), borcaptate (bsh) and liposomal borcaptat as boron delivery drugs.Materials and methods. Human cell cultures: glioblastoma (u87), colorectal human adenocarcinoma (sw-620), human melanoma (sk-mel28) and primary embryonic cell lines were irradiated with a neutron flux at the presence of bpa, bsh and liposomal bsh with a concentration of 10b 40 μg/ml. The short-term cytotoxic effect of irradiation was evaluated using trypan blue. Cell survival 96 hours after irradiation was determined using mtt test, and survival fraction was evaluated using the clonogenic test.Results. Early cytotoxic effects of irradiation were not observed for all 4 cell lines. According to mtt and clonogenic tests, the most pronounced effect of bnct was noticed for sw-620 and u87 lines, regardless of boron delivery drug used. For sk-mel28 line, the best effect was achieved after irradiation with liposomal borocaptate. For the primary transplanted embryonic line, high toxicity was revealed when bnct was performed with borphenylalanine and borcaptate.Conclusion. The data obtained indicate that the accelerator-based bnct using boron delivery drugs, such as borphenylalanine, borcaptate and liposomal borcaptat, has a positive effect on tumor lines of glioblastoma, colorectal adenocarcinoma and melanoma.

Liposomes encapsulated with lipophilic derivative of 1,2-dicarba-closo-dodecaborane have been obtained and tested for toxicity to glioblastoma U87 cells and biodistribution on a U87MG xenograft mouse model. The liposomes are able to penetrate the tumor and provide boron concentration up to 1.5 mmmmg g–1 with tumor-to-muscle ratio up to 2.4.

The determination of boron in animal organ tissues using inductively coupled plasma atomic emission spectroscopy (ICP AES) has been optimized for analytical support of boron neutron capture therapy of cancerous tumors. The proposed technique is universal and rapid. The methodology includes: preliminary acid decomposition at elevated temperatures and pressure (if necessary), determination of boron by ICP AES in the obtained solutions using reference samples based on single-element solutions. The method is verified by spike experiment and varying the weight-samples. The ICP AES technique was used to evaluate the accumulation of boronophenylalanine and borocaptate in mice organs. Biodistribution of 10 B in the case of intravenous administration of the drug to SCID mice with SPF status using the human glioblastoma cell line U87 was investigated.

Boron neutron capture therapy (BNCT), a binary cancer therapeutic modality, has moved to a new phase since development of accelerator-based neutron sources and establishment of BNCT centers in Finland and Japan. That stimulated efforts for better boron delivery agent development. As liposomes have shown effective boron delivery properties and sufficient tumor retention, fluorescent liposome labelling may serve as a rapid method to study initial ability of newly synthesized liposomes to be captured by tumor cells prior to experiments on boron accumulation and neutron irradiation. In this work, we studied the accumulation and biodistribution of pegylated liposomes with encapsulated borocaptate (BSH) and a fluorescent label (Nile Red) in U87 (human glioblastoma), SW-620 (human colon carcinoma), SK-MEL-28 (human melanoma), FetMSC (mesenchymal human embryo stem cells), and EMBR (primary embryocytes) cell lines as well as an orthotopic xenograft model of U87 glioma in SCID mice. Results indicate that fluorescent microscopy is effective at determining the intracellular localization of the liposomes using a fluorescent label. The synthesized, pegylated liposomes showed higher accumulation in tumors compared to normal cells, with characteristic concentration peaks in SW-620 and U87 cell lines, and provided in vivo tumor selectivity with several-fold higher tumor tissue fluorescence at the 6-h timepoint.

Бор-нейтронозахватная терапия (БНЗТ) является бинарной формой лучевой терапии, основанная на селективном уничтожении клеток злокачественных опухолей, таких как анапластическая астроцитома и глиобластома.В ИЯФ им.Г.И.Будкера СО РАН был предложен и сконструирован источник эпитепловых нейтронов ускорительного типа, на котором был проведен ряд доклинических экспериментов по БНЗТ на клеточных культурах и лабораторных животных.Исследование выполнено на иммунодефицитных 8-10 недельных самцах мышей линии SCID SPF-статуса.За 18-21 день до начала эксперимента проводили подготовку клеток глиобластомы человека линии U87, доводя до концентрации 100 тыс.клеток в 1 мкл и вводили интракраниально для получения внутримозгового объемного образования.Все эксперименты на животных были одобрены межинститутской комиссией по биоэтике и соответствуют принципам Руководства по уходу и использованию лабораторных животных, изданного US NIH (№ 85-23, пересмотрено в 1985 г.).В качестве препарата адресной доставки моноизотопа бора В 10 использовали традиционные и зарекомендовавшие себя медицинские препараты -L-p-борфенилаланин ВРА, боркаптат BSH, а также альтернативные соединения на основе карборанов, содержащие достаточное количество атомов бора.Для оценки эффективности накопления препаратов в опухоли и построения кинетических кривых выведения была разработана АЭС ИСП методика определения В. Методика включает предварительное кислотное разложение органов в микроволновой системе MARS-5 (HNO 3 , H 2 O 2 и/или их смеси).Содержание бора определяли на спектрометре АЭС ИСП iCAP-6500 (Thermo), регистрацию эмиссионных спектров проводили в условиях, рекомендованных производителем.Для обеспечения правильности полученных результатов изучили влияние основы на аналитический сигнал наиболее ярких спектральных линий.Изучена целесообразность применения внутреннего стандарта.Градуировочные зависимости строили с использованием одноэлементного раствора ионов бора