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A comparative analysis of three single nucleotide variations of the proteasomal genes PSMA3 (rs2348071) and PSMA6 (rs2277460 and rs1048990) was carried out in the groups of children from 1 to 16 years old with the autoimmune rheumatic disease - juvenile idiopathic arthritis (JIA; n = 199), with articular syndrome of non-autoimmune etiology (n = 229) and in the clinical control group with neither autoimmune nor chronic inflammatory diseases (n = 379). PCR, PCR–RFLP and real-time PCR were used for genotyping. It was found that the CG genotype and G allele of rs10489990 polymorphism (OR = = 1.93; 95 % CI 1.29-2.90; p = 0.002 and OR = 1.51; 95 % CI 1.11-2.04; p = 0.008 respectively), as well as the AA genotype of rs2348071 polymorphism (OR = 1.89; 95 % CI 1.02–3.49; p = 0.044) are associated with the JIA susceptibility, but not with articular syndrome. The established JIA risk genotypes may indicate the involvement of PSMA3 and PSMA6 genes in the development of an autoimmune reaction. In combination with other risk DNA markers, they can be proposed to assess a genetic predisposition to JIA. It was also revealed that the frequencies of risk genotypes and alleles for JIA in the group of patients with articular syndrome as a whole occupy an intermediate position between JIA and control group frequencies. This may indicate an increased JIA risk in some patients with articular syndrome.

The earliest fully aquatic cetaceans arose during the Middle Eocene; however, the earliest stage of their divergence is obscure. Here, we provide a detailed redescription of an unusual early cetacean, “Platyosphys einori”, from the Late Eocene of Ukraine (37.8–35.8 million years ago), with new data on its body size, skeletal microanatomy and suggestions on phylogenetic relationships. The procedure of regression analysis has been developed for the body size estimation from the size of the longest vertebra and the width of a cervical vertebra. “Platyosphys einori”, identified here as Basilosauridae incertae sedis, is a fully aquatic cetacean with a pronounced neck, poorly developed or low frequency underwater hearing, and it has a mix of plesiomorphic and derived traits. It is unusually large for a cetacean of that time, approximately 10 m long, and it is possibly very young and fast-growing for its body size. There is no pachyosteosclerotic cortex in vertebrae, and there is a large amount of spongy tissue in the rib. Therefore, “Platyosphys einori”, even if juvenile, is at the intermediate stage between early cetaceans with osteosclerotic bones and modern whales with osteoporotic skeleton. Thus, “Platyosphys einori” shows adaptations to life in water typical for modern whales but unique for the Eocene cetaceans.

Conducting a pilot study to assess the effect of thermal heliox on the state of the respiratory tract by studying of the exhaled breath condensate protein composition before the thermal heliox procedure, immediately after and after three hours of relaxation Materials and methods. A comparative study of the exhaled breath condensates (EBC) protein composition of five non-smoking healthy donors was carried out. The EBC was taken before the respiratory procedure, immediately after a 20-minute inhalation by mixture of He/O2 gases (70/30) heated to 70C and 3 hours later. The protein composition was determined by chromatography-mass spectrometric analysis after selective tryptic hydrolysis. The results were processed using the Mascot program and the UniProt database.After the heliox procedure, the volume of the collected condensate (11.5 ml) decreases by an average of 32% and is practically restored after three hours of relaxation. Most proteins were consistent for all samples, regardless of the thermal heliox procedure. These are keratins, several proteins of the immune system (immunoglobulins, compliment proteins), tubulin. In samples after thermal heliox, the appearance of small amounts of additional proteins is observed. These are proteins of muscle metabolism (actin and calmodulin), fibrinogen, traces of hemoglobin, apolipoprotein, type B creatine kinase. After three hours of relaxation, tubulin disappears in the EBC.Most exhaled proteins are the same before, after the procedure, and for three hours of relaxation. The results obtained demonstrate the relative safety of the use of high temperature heliox as a therapeutic agent.Цель. Проведение пилотного исследования по оценке влияния термического гелиокса на состояние респираторного тракта с помощью изучения белкового состава конденсата выдыхаемого воздуха до процедуры термического гелиокса, сразу после и спустя 3 ч релаксации. Материалы и методы. Проведено сравнительное исследование белкового состава конденсатов выдыхаемого воздуха (КВВ) 5 некурящих здоровых доноров. КВВ отбирали до дыхательной процедуры, сразу после 20-минутной ингаляции, нагретой до 70С смеси газов Не/О2 (70/30), и 3 ч спустя. Белковый состав определяли методом хромато-масс-спектрометрического анализа после селективного триптического гидролиза. Обработка результатов осуществлялась с использованием программы Mascot и базы данных UniProt. Результаты. После процедуры гелиокса объем собираемого конденсата (11,5 мл) падает в среднем на 32% и практически восстанавливается после 3-часовой релаксации. Основная часть белков постоянна для всех проб, независимо от процедуры термического гелиокса. Это кератины, несколько белков иммунной системы (иммуноглобулины, белки комплимента), тубулин. В пробах после термического гелиокса наблюдается появление в небольших количествах дополнительных белков. Это белки мышечного метаболизма (актины и кальмодулины), фибриноген, следы гемоглобина, аполипопротеина, креатинкиназы В типа. После 3-часовой релаксации в КВВ исчезает тубулин. Заключение. Большая часть выдыхаемых белков одинакова до, после процедуры и 3-часовой релаксации. Полученные результаты демонстрируют относительную безопасность применения высокотемпературного гелиокса как терапевтического средства.

The article deals with history of small benthic foraminifera biostratigraphy of Paleogene deposits the southern Ukraine. The significance of O.K. Kaptarenko-Chernousova, A.M. Voloshina, M.V. Yartseva, Ye.Ya. Kraeva, A.P. Pechenkina, N.G. Savenko and I.D. Konenkova’s works on study foraminifera is shown. Due to their investigarions the sequence and space-time relationships of Paleogene small benthic foraminifera assemblages have been determined in the southern Ukraine. Comparison foraminifera assemblages of Paleogene the southern Ukraine with intergerional benthic foraminifera zones of the Crimea-Caucasus Region is given. The article provides full references to previous literature on Paleogene foraminiferal biostratigraphy of the northern Peri-Black Sea Region and the southern slope of Ukrainian Shield. Up to the beginning the seventies years of the last century the researchers had distinguished and had described foraminifera assemblages characterizing Series and regional units of Paleogene the southern Ukraine. Taxonomic composition of benthic foraminifera assemblages was defined. Their spreading in Paleogene section of the northern Peri-Black Sea Region, the southern slope of Ukrainian Shield and adjacent part the Azov Crystalline Massif was studied. For some foraminifera assemblages the regional significance has been proved. Other assemblages are important for characterizing and dating suites, members, stratum and beds of the local stratigraphic schemes. Foraminifera associations of relatively deep-water depositional environments of the south of the northern Peri-Black Sea Region include species of zonal assemblages of interregional benthic foraminifers zones the Crimea-Caucasus Region. The most of distinguished benthic foraminifera assemblages are characteristic for shallow- and marginal-marine sediments of Paleogene basin in the northern Peri-Black Sea Region and its peripheral facies within depressions the southern slope of Ukrainian Shield. The space-time relations of benthic foraminifera assemblages are defined for Paleogene regional stages of the southern Ukraine section.

The high efficiency of using thermoheliox (inhalation with a high-temperature mixture of helium and oxygen) in the treatment of patients affected by COVID-19 was shown. The dynamics of accumulation of IgG, IgM, and C-reactive protein (CRP) in patients with coronavirus infection in the "working" and control groups was studied experimentally. It was shown that thermoheliox intensifies the synthesis of IgG, IgM, and CRP antibodies, while eliminating the induction period on the kinetic curves of the synthesis of specific antibodies in the IgG form and transfers the synthesis of CRP to a fast phase. The results of experiments confirm the previously obtained data based on the analysis of the kinetic model of the development of coronaviral infection in the human body.

The aim of the research study is to investigate changes of lipid peroxide oxidation (PLO) indices and antioxidant system (AOS) of rats’ heart, liver and brain during the administration of adrenalin cardiotoxic dose.Material and methods. Experiments were carried out on white non-pedigreed male-rats weighing 180–220 grams of two groups: control and pilot — with adrenalin affection (in ten rats). Adrenalin affection was caused by intramuscular injection of 0,18% adrenalin hydrotartrate solution (1mg/kg of mass).The investigation was carried out in an hour after adrenalin injection. Concentrations of diene conjugate (DC), malonic aldehyde (MA), vitamin E, thiol groups, activity of superoxide dismutase (SOD) were determined in rats’ heart, liver and brain. Statistical processing of digital data was performed by means of ”Excel” (“Microsoft”, USA) and “STATISTICA” 6.0 (“Statsoft”, USA). Adequacy of value variations between independent quantities was determined by Student criterion.Results. In control group of animals the highest activity of PLO and AOS was observed in the liver, the lowest was in the heart. Concentrations of MA and vitamin E were the highest in the liver homogenate. SOD activity was the smallest in the heart. The content of thiol groups was larger in the liver homogenate in comparison with results in the heart. DC, SH groups were increased in the heart in an hour after adrenalin injection. DC, MA, SS groups were increased in the liver but the content of vitamin E was decreased. Concentrations of DC, MA, thiol groups, SOD activity were increased in the brain but vitamin E concentration was decreased. DC and MA content, thiol groups, SOD concentration were the lowest in homogenate of the heart. The highest content of vitamin E was in the liver. The following correlations were discovered after adrenalin injection: concentration of vitamin E between the liver and heart (r=-0,82; р

Some modifications for Biostratigraphic Scheme of Paleocene deposits of the Northern Ukraine as result of examination of foraminifera assemblages of the Dnieper-Donets Depression and Ukrainian Shield are proposed. In the Northern Ukraine section sediments of Psolian regional stage (regiostage) contain the most representative assemblages of planktonic and benthic foraminifera. Two planktonic foraminifers’ zones Subbotina trivialis – Globoconusa daubjergensis – Globanomalina compressa and Praemurica inconstans established earlier by M.V. Jartseva (1972) characterize the Psolian regiostage. Subbotina trivialis – Globoconusa daubjergensis – Globanomalina compressa zone corresponding to Eoglobigerina taurica and Globoconusa daubjergensis zones of the Belokamenskian regiostage of the Southern Ukraine is correlated with Danian zone P1 Eoglobigerina edita of tropical planktonic foraminiferal biochronological zonation. Praemurica inconstans zone of the Northern Ukraine corresponds to south Ukraine zone of the same name and is correlated with zone P2 Praemurica uncinata of Danian too. Benthic foraminifers’ assemblages from Psolian deposits have been distinguished as Cibicides lectus zone corresponding to Anomalina danica s. l. and Pyramidina crassa interregional zones of Danian and Zelandian of the south Russia and adjacent regions. Reviewed in the article biostratigraphical characteristics of local stratigraphic units of Psolian regiostage: the Sumy Suite of the Dnieper-Donets Depression (zones Subbotina trivialis – Globoconusa daubjergensis – Globanomalina compressa, beds with Cibicidoides lectus, beds with Cibicidoides favorabilis of the central part of the Depression; Anomalina danica zone, Ceratolamarckina tuberculata local zone, beds with Parasubbotina pseudobulloides and beds with Globoconusa kozlowskii of the north-eastern part of the Depression), Strata of quartz-glauconitic sands of the Konka-Yalyn Depression (beds with Parasubbotina pseudobulloides, beds with Cibicidoides lectus), the Luzanovka Beds (beds with Parasubbotina pseudobulloides, beds with Globoconusa daubjergensis, beds with Elphidiella prima) and the Polesje Beds (beds with Parasubbotina pseudobulloides, beds with Cibicidoides lectus), the Rajgorod Suite (assemblage with Anomalina danica) of the Ukrainian Shield. Correlation of these Suites, Beds and Strata are given. The Merlian regiostage of the Northern Ukraine contains not numerous foraminifers. Benthic foraminifers’ associations from the Merlian and Irzhavets Suites of the Dnieper-Donets Depression have been distinguished as assemblage with Bolivinopsis spectabilis. Sediment containing this assemblage is of Thanetian age by dinocysts. Findings of sporadic planktonic foraminifers in the Merlian deposits do not contradict this.

Clinical trials of thermoheliox application (inhalation with a high-temperature mixture of oxygen and helium, 90 °C) in the treatment of the acute phase of coronavirus infection were conducted. Dynamics of disease development in infected patients (PCR test for the virus) and, dynamics of changes in blood concentration of C-reactive protein, immunoglobulin M, specific immunoglobulin G were studied. High efficiency of thermoheliox in releasing the organism from the virus and stimulating the immune response (thermovaccination effect) was shown. The kinetic model of the process is proposed and analyzed., Graphical abstract Image 1, Highlights • Clinical trials of thermoheliox application in the treatment of acute phase of coronavirus were performed. • High efficiency of thermoheliox in stimulating the immune response (thermovaccination effect) was shown. • Influence of thermoheliox on IgG synthesis kinetics and kinetic behavior of C-reactive protein is studied. • Kinetic model for the synthesis of antibodies and CRP is proposed.

Запропонована біостратиграфічна схема морського палеогену Східного Приазов’я за форамініферами. Описані угруповання форамініфер верхньобілокам’янського (комплекс з Anomalina danica, Cibicidoides ex gr. lectus), качинського (Acarinina subsphaerica), сімферопольського (Acarinina bullbrooki), новопавлівського (Acarinina rotundimarginata, Hantkenina alabamensis), кумського (Subbotina turkmenica), альмінського (верстви з Globigerapsis tropicalis, верстви з Bolivina antegressa) і планорбеллового (верстви з Trifarina transcaspiensis, верстви з Lenticulina herrmanni, верстви з Spiroplectammina carinata oligocenica) горизонтів. Проведена кореляція новоазовської, щербацької, саханської товщ, єланчицької і борисфенської світ Східного Приазов’я зі стратонами Західного Приазов’я та Азово-Кубанської западини за форамініферами.

The purpose of this investigation has been the analysis of the long-term development of biological damage in natural populations of a model mammalian species, the bank vole (Clethrionomys glareolus, Schreber), which were chronically exposed to low doses of ionizing radiation over 22 animal generations within 10 years following the Chernobyl accident. The time course of the biological end-points (chromosome aberrations in bone marrow cells and embryonic lethality) was compared with the time course of the whole-body absorbed dose rate from external and internal exposure in the studied populations inhabiting monitoring sites in Belarus with different ground deposition of radionuclides. The yield of chromosome aberrations and, in lesser degree, embryonic lethality was associated with the radionuclide contamination of the monitoring areas in a dose-dependent manner. As a main feature of the long-term development of biological damage under low dose rate irradiation, permanently elevated levels of chromosome aberrations and an increasing frequency of embryonic lethality have developed over 22 animal generations. This contrasts with the assumption that the biological damage would gradually disappear since in the same period of time the whole-body absorbed dose rate decreased exponentially with a half-value time of about 2.5-3 years. Furthermore, gravid females were captured, and their offspring, born and grown up under contamination-free laboratory conditions, showed the same enhanced level of chromosome aberrations. Therefore the authors suggest that, along with the biological damage attributable to the individual exposure of each animal, the observed cellular and systemic effects reflect the transgenerational transmission and accumulation, via genetic and/or epigenetic pathways, of damage attributable to the chronic low-dose rate exposure of the preceding generations of animals. They also suggest that the level of the accumulated transmissible damage in the investigated populations will decrease in future due to the further recession of the chronic exposure and as a consequence of selection processes.

Luminescence and absorption stains specific for DNA (acridine orange, ethidium bromide), proteins (silver nitrate), and lipids (Sudan III) were used to study the distribution of DNA, proteins, and lipids in sections of the olfactory bulb in rats, studies being performed after fixation of brains with paraformaldehyde. DNA was found to be more abundant in the glomerular cell layer than the mitral cell layer. Higher quantities of DNA were present in the granular layer, located beneath the mitral layer. The characteristics of cell layers in the olfactory bulb were studied in rats aged two days and one month. There were differences between the layers of rats of different ages in terms of the content and distribution of DNA, though there were no differences in the total protein or lipid contents. Glomeruli were immature in two-day-old rats.

Dynamics of population mutagenesis during 22 consecutive generations of animals, as well as genetic radioadaptation were studied in natural populations of small mammals (bank voles) under chronic low‐intensive irradiation due to the Chernobyl accident. The data obtained point to oppositely directed processes in irradiated populations: accumulation of mutations (genetic load of populations) and formation of genetic radioadaptation. It is suggested that the frequencies of genetic damages in populations could be higher in the absence of radioadaptation process. A relationship between the frequencies of cytogenetic injuries and low doses of radiation was revealed in animal generations studied. The non‐linear dose‐effect curves are most likely to be defined by the complicated microevolutionary processes in populations. The results obtained indicate the absence of genetic effect threshold of low dose radiation. Besides, they show that a dependence of cytogenetic effects on radiation low doses in series of irradiated generations cannot be revealed using linear equations.

The time course of the formation of micronucleated polychromatic (MNPCEs) and normochromatic erythrocytes (MNNCEs) in the bone marrow of the bank vole (Clethrionomys glareolus, Schreber), a model mouse-like species, was studied using the standard micronucleus test at 0, 6, 12, 18, 24, 30, 36 and 48 hr following whole-body acute γ-irradiation at a dose of 0.5 Gy. Based on the existing literature on laboratory mice, it was suggested that such a dose will not have significant effect on erythroid cell proliferation in the bank vole and hence on the time course of the rise of micronucleated cells. In total, ∼905,000 polychromatic (PCEs) and normochromatic erythrocytes (NCEs) from 82 adult bank voles were analyzed. Although the mean frequencies of MNNCEs were too low to allow for the correct assessment of their time course, an analysis of PCEs showed an increasing rate of MNPCE appearance at 6 hr that reached a maximum at 18-24 hr after irradiation and subsequently decreased. Because the kinetics of MNPCEs reflects the process of erythropoiesis, the current results regarding the time points of appearance of radiation-induced MNPCEs provide the first information on the prolongation of one of the terminal stages of erythrocyte formation in bank vole specimens, namely the stage of maturation of PCEs from erythroblasts. Moreover, the observed time-course data, as well as the low-background frequencies of MNPCEs and characteristic level of PCEs response to radiation, showed similarities between the two model species: bank vole (this study) and laboratory mice (literature data).

In prostate cancer (PCa) patients, initial responsiveness to androgen deprivation therapy is frequently followed by relapse due to development of treatment-resistant androgen-independent PCa. This is typically associated with acquisition of mutations in AR that allow activity as a transcription factor in the absence of ligand, indicating that androgen-independent PCa remains dependent on AR function. Our strategy to effectively target AR in androgen-independent PCa involved using a cell-based readout to isolate small molecules that inhibit AR transactivation function through mechanisms other than modulation of ligand binding. A number of the identified inhibitors were toxic to AR-expressing PCa cells regardless of their androgen dependence. Among these, some only suppressed PCa cell growth (ARTIS), while others induced cell death (ARTIK). ARTIK, but not ARTIS, compounds caused disappearance of AR protein from treated cells. siRNA against AR behaved like ARTIK compounds, while a dominant negative AR mutant that prevents AR-mediated transactivation but does not eliminate the protein showed only a growth suppressive effect. These observations reveal a transcription-independent function of AR that is essential for PCa cell viability and, therefore, is an ideal target for anti-PCa treatment. Indeed, several of the identified AR inhibitors demonstrated in vivo efficacy in mouse models of PCa and are candidates for pharmacologic optimization.

The aim of this pilot study was to assess whether a compound of the β-carbonyl-1,4-dihydropyridine series (AV-153 or sodium 3,5-bis-ethoxycarbonyl-2,6-dimethyl-1,4-dihydropyridine-4-carboxylate), which has high efficiency in stimulating DNA repair, can simultaneously modulate apoptosis in human cells. Peripheral blood lymphocytes of healthy donors were used in this study. DNA strand-break rejoining was assessed with the alkaline comet assay after a 3-h incubation of lymphocytes in the presence of a wide range of concentrations of AV-153 (10−10–10−5 M). Apoptotic and micronucleated (MN) cells were scored in phytohaemagglutinin-stimulated lymphocytes after a 72-h incubation with AV-153, using the standard cytokinesis-blocked micronucleus test. The study revealed dual effects of AV-153 on cellular defense systems against endogenously generated DNA damage: the compound per se simultaneously reduces DNA strand breaks and stimulates apoptosis, with a maximal efficiency of 76% and 42%, respectively; in contrast, after genotoxic stress (2 Gy of gamma-radiation) AV-153 reduces DNA strand breaks, the number of MN cells and apoptotic cells in a similar dose-dependent manner. A maximal efficiency of 67% was found for reduction of DNA strand breaks, while for MN cells and apoptotic cells the efficiencies were, respectively, 47% and 44%. While limited in number, these preliminary studies show the direct correlation between the efficiency of AV-153 in reduction of radiation-induced DNA breaks and MN cells on one side, and in reduction of apoptosis on the other. It suggests that the major target of the compound's action on genotoxic stress is DNA repair, followed by reduction of the number of damaged cells entering apoptosis.

Antibodies to the prion protein (PrP), particularly, monoclonal antibodies, are necessary tools in the diagnostics and study of prion diseases and potential means of their immunotherapy. For the production of monoclonal antibodies, BALB/c mice were immunized by a recombinant bovine PrP. Three stable hybridomas producing antibodies of IgM class were prepared. The antibodies were bound to PrP in a solid-phase enzyme immunoassay and immunoblotting. The epitope mapping accomplished with the use of synthetic peptides showed that an epitope located in region 25-36 of PrP corresponds to one antibody, and epitopes located in region 222-229, to the other two. The antibodies to fragment 222-229 purified by affinity chromatography recognized with a high specificity conglomerates of a pathogenic prion in the brain tissue of cows suffering from spongiform encephalopathy. Thus, in nontransgenic mice, PrP-specific monoclonal antibodies were produced, useful in studies and diagnostics of prion diseases.

ADP-ribose polymers are rapidly synthesized in cell nuclei by the poly(ADP-ribose) polymerases PARP-1 and PARP-2 in response to DNA strand interruptions, using NAD(+) as precursor. The level of induced poly(ADP-ribose) formation is proportional to the level of DNA damage and can be decreased by NAD(+) or PARP deficiency, followed by poor DNA repair and genomic instability. Here we studied the correlation between poly(ADP-ribose) level and DNA strand break repair in lymphoblastoid Raji cells. Poly(ADP-ribose) synthesis was induced by 100 microM H(2)O(2) and intensified by the 1,4-dihydropyridine derivative AV-153. The level of poly(ADP-ribose) in individual cells was analyzed by quantitative in situ immunofluorescence and confirmed in whole-cell extracts by Western blotting, and DNA damage was assessed by alkaline comet assays. Cells showed a approximately 100-fold increase in poly(ADP-ribose) formation during the first 5 min of recovery from H(2)O(2) treatment, followed by a gradual decrease up to 15 min. This synthesis was completely inhibited by the PARP inhibitor NU1025 (100 microM) while the cells treated with AV-153, at non-genotoxic concentrations of 1 nM-10 microM, showed a concentration-dependent increase of poly(ADP-ribose) level up to 130% after the first minute of recovery. The transient increase in poly(ADP-ribose) level was strongly correlated with the speed and efficiency of DNA strand break rejoining (correlation coefficient ror = 0.92, p0.05). These results are consistent with the idea that poly(ADP-ribose) formation immediately after genome damage reflects rapid assembly and efficient functioning of repair machinery.

Розглянуто питання біостратиграфії палеоценових відкладів Південної України за планктонними форамініферами. Наведено зарактеристику зон Parvularugoglobigerina eugubina, Eoglobigerina taurica, Globoconusa daubjergensis, Praemurica inconstans, Morozovella angulata s.l. (Morozovella angulata s.s., Morozovella conicotruncata), Igorina dlanensis, Acarinina subsphaerica, Acarinina acarinata. Дано співвідношення зон планктонних форамініфер із зонами за нанопланктоном. Зональні комплекси планктонних форамініфер білокам’янського і качинського регіоярусів Південної України скорельовані із зонами планктонних форамініфер датського, зеландського і танетського ярусів Міжнародної стратиграфічної шкали.

Compounds of the 1,4-dihydropyridine (1,4-DHP) series have been shown to reduce spontaneous, alkylation- and radiation-induced mutation rates in animal test systems. Here we report studies using AV-153, the 1,4-DHP derivative that showed the highest antimutagenic activity in those tests, to examine if it modulates DNA repair in human peripheral blood lymphocytes and in two human lymphoblastoid cell lines, Raji and HL-60. AV-153 caused a 50% inhibition of growth (IC50) of Raji and HL-60 cells at 14.9+/-1.2 and 10.3+/-0.8mM, respectively, but did not show a cytotoxic effect at concentrations

As a determinant of the associated health risks, the behavior of radionuclides in natural ecosystems needs to be better understood. Therefore, the activity concentration of various long-lived radionuclides released due to the Chernobyl accident, and the corresponding contributions to the whole-body dose rate, was studied as a function of time in mammalian indicator species inhabiting the natural forest ecosystems of Belarus, the bank vole (Clethrionomys glareolus) and the yellow-necked mouse (Apodemus flavicollus). The activity concentrations of 137Cs, 134Cs, 90Sr, 238Pu, 239,240Pu, 241Pu and 241Am in soil and in animals were measured at five monitoring sites with different ground deposition of radionuclides at different distances from the destroyed reactor. The observed temporal pattern of the radionuclide activity concentration in the studied animal populations reflects the changes in biological availability of these isotopes for biota, mostly due to fuel particle destruction and appearance of dissolved and exchangeable forms of radionuclides. The time course of 134+137Cs activity concentrations in animal populations appeared as a sequence of increase, peak and decrease. Maximal levels of radiocesium occurred 1-2 years after deposition, followed by an exponential decrease. Concentrations of incorporated 90Sr increased up to the tenth year after deposition. The activity concentrations of transuranic elements (238Pu, 239,240Pu, 241Pu and 241Am) were much lower than those of the other radionuclides, in the studied animals. A considerable activity of 241Am in animals from areas with high levels of contamination was firstly detected 5 years after deposition, it increased up to the tenth year and is expected to increase further in the future. Maximal values of the whole-body absorbed dose rates occurred during the year of deposition, followed by a decrease in the subsequent period. Generally, this decrease was monotonic, mainly determined by the decrease of the external gamma-ray dose rate, but there were exceptions due to the delayed maximum of internal exposure. The inter-individual distributions of radionuclide concentrations and lifetime whole-body absorbed doses were asymmetric and close to log-normal, including concentrations and doses considerably higher than the population mean values.