Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Iran Biomed J ; 26(6): 475-84, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36380684

RESUMO

Introduction: Introduction: Chemotherapy, biotherapy, and radiotherapy play a limited but important role in treating breast cancer. For more efficient treatment, combination therapy could be an appropriate option. In this study, radiotherapy using neutron radiation emitted from a 241Am-Be neutron source, as well as biotherapy using curcumin (80 µM) was combined to investigate the efficiency of treatment towards MCF-7 breast cancer in a three dimensional (3D) culture medium. Methods: Methods: MTT, neutral red uptake assay, nitric oxide, glutathione assay, catalase, cytochrome c, comet assay, and caspase-3 were used to determine the effect of neutron radiation and also neutron and curcumin combination on the viability of cancer cells. Results: Results: The results of cytotoxicity test showed that neutron irradiation with or without curcumin at 5, 10, 15, and 20 h reduced the survival of tumor cells. Moreover, the rate of apoptosis due to the neutron effect at different irradiation times enhanced with the increasing time. Conclusion: Conclusion: Due to the significant anticancer effect of curcumin in 3D culture, using this molecule before or after neutron therapy is recommended.


Assuntos
Neoplasias da Mama , Curcumina , Humanos , Feminino , Curcumina/farmacologia , Neoplasias da Mama/patologia , Amerício/farmacologia , Amerício/uso terapêutico , Apoptose , Nêutrons , Linhagem Celular Tumoral
2.
Artigo em Inglês | MEDLINE | ID: mdl-22795580

RESUMO

The integral bioluminescence (BL) intensity of live Photobacterium phosphoreum cells (strain 1883 IBSO), sampled at the stationary growth stage (20 h), was monitored for further 300 h in the absence (control) and presence of (241)Am (an α-emitting radionuclide of a high specific activity) in the growth medium. The activity concentration of (241)Am was 2 kBq l(-1); [(241)Am]=6.5×10(-11) M. Parallel experiments were also performed with water-soluble humic substances (HS, 2.5 mg l(-1); containing over 70% potassium humate) added to the culture medium as a possible detoxifying agent. The BL spectra of all the bacterial samples were very similar (λ(max)=481±3 nm; FWHM=83±3 nm) showing that (241)Am (also with HS) influenced the bacterial BL system at stages prior to the formation of electronically excited states. The HS added per se virtually did not influence the integral BL intensity. In the presence of (241)Am, BL was initially activated but inhibited after 180 h, while the system (241)Am+HS showed an effective activation of BL up to 300 h which slowly decreased with time. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, applied to dry cell biomass sampled at the stationary growth phase, was used to control possible metabolic responses of the bacteria to the α-radioactivity stress (observed earlier for other bacteria under other stresses). The DRIFT spectra were all very similar showing a low content of intracellular poly-3-hydroxybutyrate (at the level of a few percent of dry biomass) and no or negligible spectroscopic changes in the presence of (241)Am and/or HS. This assumes the α-radioactivity effect to be transmitted by live cells mainly to the bacterial BL enzyme system, with negligible structural or compositional changes in cellular macrocomponents at the stationary growth phase.


Assuntos
Amerício/farmacologia , Substâncias Húmicas/análise , Medições Luminescentes/métodos , Photobacterium/efeitos dos fármacos , Photobacterium/metabolismo , Biomassa , Viabilidade Microbiana/efeitos dos fármacos , Photobacterium/citologia , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo
3.
Radiat Oncol ; 6: 64, 2011 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-21651780

RESUMO

BACKGROUND: Various types of radiation effects in mammalian cells have been studied with the aim to predict the radiosensitivity of tumours and normal tissues, e.g. DNA double strand breaks (DSB), chromosome aberrations and cell reproductive inactivation. However, variation in correlations with clinical results has reduced general application. An additional type of information is required for the increasing application of high-LET radiation in cancer therapy: the Relative Biological Effectiveness (RBE) for effects in tumours and normal tissues. Relevant information on RBE values might be derived from studies on cells in culture. METHODS: To evaluate relationships between DNA-DSB, chromosome aberrations and the clinically most relevant effect of cell reproductive death, for ionizing radiations of different LET, dose-effect relationships were determined for the induction of these effects in cultured SW-1573 cells irradiated with gamma-rays from a Cs-137 source or with α-particles from an Am-241 source. RBE values were derived for these effects. Ionizing radiation induced foci (IRIF) of DNA repair related proteins, indicative of DSB, were assessed by counting gamma-H2AX foci. Chromosome aberration frequencies were determined by scoring fragments and translocations using premature chromosome condensation. Cell survival was measured by colony formation assay. Analysis of dose-effect relations was based on the linear-quadratic model. RESULTS: Our results show that, although both investigated radiation types induce similar numbers of IRIF per absorbed dose, only a small fraction of the DSB induced by the low-LET gamma-rays result in chromosome rearrangements and cell reproductive death, while this fraction is considerably enhanced for the high-LET alpha-radiation. Calculated RBE values derived for the linear components of dose-effect relations for gamma-H2AX foci, cell reproductive death, chromosome fragments and colour junctions are 1.0 ± 0.3, 14.7 ± 5.1, 15.3 ± 5.9 and 13.3 ± 6.0 respectively. CONCLUSIONS: These results indicate that RBE values for IRIF (DNA-DSB) induction provide little valid information on other biologically-relevant end points in cells exposed to high-LET radiations. Furthermore, the RBE values for the induction of the two types of chromosome aberrations are similar to those established for cell reproductive death. This suggests that assays of these aberrations might yield relevant information on the biological effectiveness in high-LET radiotherapy.


Assuntos
Aberrações Cromossômicas , Quebras de DNA de Cadeia Dupla/efeitos da radiação , DNA/efeitos da radiação , Partículas alfa , Amerício/farmacologia , Carcinoma de Células Escamosas/radioterapia , Linhagem Celular Tumoral , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , Radioisótopos de Césio , Cromossomos/efeitos da radiação , Reparo do DNA/efeitos da radiação , Relação Dose-Resposta à Radiação , Humanos , Neoplasias Pulmonares/radioterapia , Radioterapia/métodos
4.
Health Phys ; 95(5): 465-92, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18849679

RESUMO

All of the actinides are radioactive. Taken into the body, they damage and induce cancer in bone and liver, and in the lungs if inhaled, and U(VI) is a chemical kidney poison. Containment of radionuclides is fundamental to radiation protection, but if it is breached accidentally or deliberately, decontamination of exposed persons is needed to reduce the consequences of radionuclide intake. The only known way to reduce the health risks of internally deposited actinides is to accelerate their excretion with chelating agents. Ethylendiaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were introduced in the 1950's. DTPA is now clinically accepted, but its oral activity is low, it must be injected as a Ca(II) or Zn(II) chelate to avoid toxicity, and it is structurally unsuitable for chelating U(VI) or Np(V). Actinide penetration into the mammalian iron transport and storage systems suggested that actinide ions would form stable complexes with the Fe(III)-binding units found in potent selective natural iron chelators (siderophores). Testing of that biomimetic approach began in the late 1970's with the design, production, and assessment for in vivo Pu(IV) chelation of synthetic multidentate ligands based on the backbone structures and Fe(III)-binding groups of siderophores. New efficacious actinide chelators have emerged from that program, in particular, octadentate 3,4,3-LI(1,2-HOPO) and tetradentate 5-LIO(Me-3,2-HOPO) have potential for clinical acceptance. Both are much more effective than CaNa3-DTPA for decorporation of Pu(IV), Am(III), U(VI), and Np(IV,V), they are orally active, and toxicity is acceptably low at effective dosage.


Assuntos
Elementos da Série Actinoide/uso terapêutico , Quelantes/administração & dosagem , Elementos da Série Actinoide/efeitos adversos , Elementos da Série Actinoide/química , Amerício/administração & dosagem , Amerício/farmacologia , Animais , Quelantes/uso terapêutico , Desferroxamina/uso terapêutico , Ácido Edético/uso terapêutico , Humanos , Camundongos , Ácido Pentético/uso terapêutico , Fenóis/administração & dosagem , Plutônio/administração & dosagem , Plutônio/isolamento & purificação , Plutônio/farmacologia , Urânio/administração & dosagem
5.
Int J Radiat Biol ; 80(2): 155-64, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15164797

RESUMO

PURPOSE: To evaluate by the fluorescent in-situ hybridization (FISH) technique the dose-response and intercellular distribution of alpha-particle-induced chromosome aberrations. In particular, the validity of using the yield of characteristic types of chromosome abnormalities in stable cells as quantitative indicators for retrospective dose reconstruction has been evaluated. MATERIAL AND METHODS: Monolayers of human peripheral lymphocytes were exposed at doses from 0.02 to 1 Gy to alpha-particles emitted from a source of americium-241. The most probable energy of the alpha-particles entering the cells was 2.7 MeV. FISH painting was performed using DNA probes for chromosomes 2, 4 and 8 in combination with a pan-centromeric probe. In complete first-division cells, identified by harlequin staining, aberrations involving painted target chromosomal material were recorded as well as aberrations involving only unpainted chromosomal material. RESULTS: In total, the percentage of complex aberrations was about 35% and no dose dependence was observed. When complex-type exchanges were reduced to simple base types, the different cell distributions were clearly over-dispersed, and the linear coefficients of the dose-effect curves for translocations were significantly higher than for dicentrics. For past dose reconstruction, only a few complex aberrations were in stable cells. The linear coefficient obtained for transmissible aberrations in stable cells was more than seven times lower than that obtained in all analysed cells, i.e. including unstable cells. CONCLUSION: FISH-based analysis of complex rearrangements allows discrimination between partial-body exposures to low-linear energy transfer radiation and high-linear energy transfer exposures. In assessing past or chronic exposure to alpha-particles, the use of a dose-effect curve obtained by FISH-based translocation data, which had not excluded data determined in unstable cells, would underestimate the dose. Insertions are ineffective biomarkers because their frequency is too low.


Assuntos
Partículas alfa , Amerício/farmacologia , Aberrações Cromossômicas , Relação Dose-Resposta à Radiação , Hibridização in Situ Fluorescente/métodos , Linfócitos/efeitos da radiação , Adulto , Células Cultivadas , DNA/ultraestrutura , Genoma , Humanos , Masculino , Estudos Retrospectivos , Translocação Genética
6.
Anticancer Res ; 18(4A): 2409-14, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9703887

RESUMO

Tumors induction by americium is well known but there are no data on the biological effects of this radionucleide at subcellular level. In order to study the possible ultrastructural lesions induced by this element, a group of rats were injected with 241-Americium-citrate (9 kBq), once a week for five weeks and sacrificed 7 days after the last injection. We describe the alterations observed in the cortex kidney using cytochemical (TUNEL reaction) and histochemical (PAS staining) methods for light microscopy as well as electron microscopy techniques. Various types of lesions were detected: condensation of nuclear chromatine, fragmentation of the nuclei, swollen mitochondria, disappearance of mitochondrial crests and skrinking of the cytoplasm. This study clearly demonstrated the induction of apoptosis by americium in rat cortex kidney cells.


Assuntos
Amerício/farmacologia , Apoptose/efeitos da radiação , Córtex Renal/efeitos da radiação , Túbulos Renais Distais/efeitos da radiação , Animais , Núcleo Celular/efeitos da radiação , Núcleo Celular/ultraestrutura , Fragmentação do DNA , Córtex Renal/patologia , Córtex Renal/ultraestrutura , Túbulos Renais Distais/patologia , Túbulos Renais Distais/ultraestrutura , Ratos , Ratos Sprague-Dawley
7.
Vestn Akad Med Nauk SSSR ; (2): 33-5, 1992.
Artigo em Russo | MEDLINE | ID: mdl-1626408

RESUMO

The authors provide the data obtained in experimental animals, pertaining to the influence of certain modifying factors on metabolism and biological effects induced by radioactive isotopes of iodine, by transuranium elements and beryllium. Out of all the modifying factors investigated, the form of the introduced compound and age turned out the most significant ones.


Assuntos
Envelhecimento/fisiologia , Radioisótopos/farmacologia , Amerício/farmacocinética , Amerício/farmacologia , Animais , Berílio/farmacocinética , Berílio/farmacologia , Feminino , Radioisótopos do Iodo/farmacocinética , Radioisótopos do Iodo/farmacologia , Plutônio/farmacocinética , Plutônio/farmacologia , Radioisótopos/farmacocinética , Ratos
8.
Radiobiologiia ; 28(3): 376-81, 1988.
Artigo em Russo | MEDLINE | ID: mdl-3399639

RESUMO

Alkaline phosphatase activity in dog blood serum was studied for two years following separate and combined exposure to gamma radiation (6.45 to 51.6 mC/kg) and inhaled submicron 239Pu oxide, containing 25 per cent of 241Am, in chronically effective amounts (approximately 7-10 kBq/kg). Alkaline phosphatase activity was of an undulatory character, and the significance of changes depended upon the kind and the level of radiation as well as the time lapsed from the start of the exposure. With the combined exposure to gamma and alpha radiation in the doses used, no enhancement of the effect was noted as compared with the action of each factor applied separately.


Assuntos
Fosfatase Alcalina/efeitos da radiação , Partículas alfa , Aerossóis , Fosfatase Alcalina/sangue , Amerício/farmacologia , Animais , Radioisótopos de Cobalto , Cães , Relação Dose-Resposta à Radiação , Feminino , Raios gama , Masculino , Tamanho da Partícula , Plutônio/farmacologia , Fatores de Tempo
9.
Health Phys ; 50(5): 595-604, 1986 May.
Artigo em Inglês | MEDLINE | ID: mdl-3700111

RESUMO

To investigate the metabolism of 241Am as affected by pregnancy and lactation, female rats were injected with 5 muCi of 241Am intravenously while nulliparous, pregnant or lactating. The females and subsequent litters were killed at various times after injection to determine 241Am distribution and retention. The temporal relationship between injection and pregnancy influenced the tissue retention of 241Am in both dams and progeny. The half-time of 241Am in livers of pregnant or lactating rats was more than twice that of nulliparous rats, although the initial uptake was approximately 50% of the activity in all groups. Both spleen and femur accumulated more 241Am at 7-10 weeks after injection than at earlier times, but this increase could not be related to pregnancy. Approximately 10 times more 241Am was transferred to offspring from dams that were lactating when exposed than was transferred via the placenta when exposure occurred late in gestation. Furthermore, more 241Am was transmitted to the progeny via milk if exposure of the dam occurred during lactation rather than during pregnancy.


Assuntos
Amerício/metabolismo , Lactação , Prenhez , Amerício/farmacologia , Animais , Feminino , Rim/metabolismo , Fígado/metabolismo , Glândulas Mamárias Animais/metabolismo , Troca Materno-Fetal , Taxa de Depuração Metabólica , Placenta/metabolismo , Gravidez , Ratos , Reprodução/efeitos dos fármacos
10.
Radiat Environ Biophys ; 23(1): 41-50, 1984.
Artigo em Inglês | MEDLINE | ID: mdl-6369378

RESUMO

The radiosensitivity of pluripotent hemopoietic stem cells was studied in ICR "Swiss" mice (28 g/mouse) given i.v. 198.6 kBq 239Pu/kg as citrate complex or 208.6 kBq 241 Am/kg as nitrate at the age of 10 weeks. The bone marrow cells were examined at the early and late phases of radionuclide contamination. To obtain data for survival curves and D0 of stem cells the CFU-S assay was used and the donor vertebral marrow cells were exposed to the complementary X-irradiation either early after injection to the heavily irradiated recipients or to the "in vitro" irradiation given before the transplantation. To determine the iron uptake in splenic erythroid progeny the recipients given marrow cells unexposed to the X-rays received 37 kBq 59Fe 6 h before they were killed and the relative activity per colony was calculated. The radiation effect of the used actinides on the bone marrow cells resulted in decreased cellularity and seriously altered both relative and absolute CFU-S numbers. The radiosensitivity of CFU-S increased in all intervals examined (D0 from 0.60 to 0.86 Gy, in controls 0.97 to 1.06 Gy) and was more expressed when the CFU-S were exposed to the X-rays immediately after the bone marrow cell transplantation to the heavily irradiated hosts. The stem cell pool appeared, especially at older age, to be affected also in its ability to produce erythrocytic progeny.


Assuntos
Amerício/farmacologia , Medula Óssea/efeitos da radiação , Células-Tronco Hematopoéticas/efeitos da radiação , Plutônio/farmacologia , Animais , Células da Medula Óssea , Transplante de Medula Óssea , Ensaio de Unidades Formadoras de Colônias , Feminino , Ferro/metabolismo , Vértebras Lombares/efeitos da radiação , Camundongos , Baço/metabolismo
11.
Health Phys ; 44 Suppl 1: 555-70, 1983.
Artigo em Inglês | MEDLINE | ID: mdl-6862930

RESUMO

Haemopoietic stem cell assays allow investigation of local radiation damage at any time after contamination. These techniques were used to determine the relative effectiveness of 241Am and 226Ra in inducing damage in various cortical and trabecular bone marrow sites. Male Balb/c mice were injected with either 230 or 660 kBq 226RaCl2/kg body weight or with one of three doses of monomeric 241Am citrate at 138, 552 or 768 kBq 241Am/kg body weight. At 7 time intervals after injection (from 4 hr to 100 days) the colony-forming capacity of pluripotent stem cells (= CFU-s) and macrophage-granulocyte committed stem cells (CFU-c) was assayed in sternal marrow, marrow of lumbar vertebrae, of the trabecular distal end of the femur and of the femoral shaft (in which were distinguished axial marrow and marrow situated peripherally near the cortical bone). 226Ra retention and 241Am retention were measured in these bone sites. Skeletal doses and doses to the bone marrow sites were calculated. On the base of injected activity, 241Am was more effective than 226Ra in reducing the number of CFU-s and CFU-c but the effectiveness varied in the various bone marrow sites. CFU-s and CFU-c response is considered in relation to the retained radioactivity in the surrounding bone matrix and in relation to the mean marrow dose.


Assuntos
Amerício/farmacologia , Células-Tronco Hematopoéticas/efeitos da radiação , Rádio (Elemento)/farmacologia , Amerício/metabolismo , Animais , Medula Óssea/efeitos da radiação , Osso e Ossos/metabolismo , Ensaio de Unidades Formadoras de Colônias , Camundongos , Camundongos Endogâmicos BALB C , Lesões Experimentais por Radiação/metabolismo , Lesões Experimentais por Radiação/patologia , Rádio (Elemento)/metabolismo , Eficiência Biológica Relativa , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...