La detection et la mesure de tres faibles niveaux de radioactivite correspondent a un besoin dans... more La detection et la mesure de tres faibles niveaux de radioactivite correspondent a un besoin dans de nombreux domaines, notamment en dosimetrie interne, dans le cadre des analyses radiotoxicologiques. Les methodes actuellement utilisees sont toutes fondees sur la detection des rayonnements. En ce qui concerne les actinides, les methodes reposent sur la mesure par spectrometrie alpha qui necessite une preparation des echantillons et un temps de comptage parfois tres long. Aujourd'hui, un grand nombre de recherches sont menees afin d'utiliser des methodes basees sur la spectrometrie de masse comme methodes, si non alternatives, au moins complementaires a la spectrometrie alpha. Dans cette etude, les performances de la spectrometrie de masse d'ions secondaires (sims) sont evaluees pour l'analyse de l'uranium, a l'etat de traces, dans des echantillons biologiques, et plus particulierement, dans des prelevements d'urine. La methode sims consiste a bombarder la surface d'un specimen avec un faisceau d'ions primaires. Les atomes des couches superficielles du specimen sont ainsi progressivement arraches, dont certains sous forme d'ions. Ces ions, appeles ions secondaires, sont ensuite analyses selon leur rapport masse sur charge. Compte tenu de son importance, l'etude debute par la recherche d'une methode de preparation des specimens adaptee au sims et egalement a la spectrometrie alpha, retenue comme methode de validation. L'utilisation de films polymeres, obtenus a partir d'un pyrrole fonctionnalise, dans lesquels l'uranium se fixe par echange ionique, s'est revelee adequate. Les essais avec les premiers specimens ainsi prepares montrent, d'une part, la sensibilite de la methode sims et, d'autre part, la possibilite d'obtenir des rapports isotopiques. La faisabilite de la methode demontree, l'etape suivante concerne l'utilisation d'un traceur pour quantifier l'uranium urinaire. Le choix s'est porte sur l'isotope #2#3#3u qui n'est que tres rarement present dans les cas d'exposition interne et dont la periode radioactive est compatible avec l'analyse par sims. Apres extraction de l'uranium contenu dans des echantillons d'urine et en appliquant le protocole etudie de preparation du specimen, la mesure par sims des rapports isotopiques #2#3#3u/#2#3#8u permet d'atteindre une limite de detection de 10#-#6 bq (10#-#10 g) en #2#3#8u par litre d'urine, pour un temps d'analyse de 5 minutes. Par ailleurs, au vu des resultats obtenus, quelques autres echantillons biologiques sont traites afin d'illustrer l'autre potentialite de la methode sims pour la recherche en dosimetrie interne, a savoir la microlocalisation analytique.
Differentiation of micronuclei (MN) caused by ionizing radiation from those caused by chemicals i... more Differentiation of micronuclei (MN) caused by ionizing radiation from those caused by chemicals is a crucial step for managing treatment of individuals exposed to radiation. MN in binucleated lymphocytes in peripheral blood are widely used as biomarkers for estimating dose of radiation, but they are not specific for ionizing radiation. MN induced by ionizing radiation originate predominantly as a result of chromosome breaks (clastogenic action), whereas MN caused by chemical agents are derived from the loss of entire chromosomes (aneugenic action). C-banding highlights centromeres, which might make it possible to distinguish radiation induced MN, i.e., as a byproduct of acentric fragments, from those caused by the loss of entire chromosomes. To test the use of C-banding for identifying radiation induced MN, a blood sample from a healthy donor was irradiated with 3 Gy of Co-60 gamma rays and cultured. Cells were harvested and dropped onto slides, divided into a group stained directly with Giemsa and another processed for C banding, then stained with Giemsa. The frequency of MN in 500 binucleated cells was scored for each method. In preparations stained with Giemsa directly, the MN appeared as uniformly stained structures, whereas after C banding, some MN exhibited darker regions corresponding to centromeres that indicated that they were not derived from acentric fragments. The C-banding technique enables differentiation of MN from acentric chromosomal material. This distinction is useful for improving the specificity of the MN assay as a biomarker for ionizing radiation.
Journal of Radioanalytical and Nuclear Chemistry, Sep 1, 2006
Thyroid cells are arranged in spheres called follicles of different sizes, in which most of the i... more Thyroid cells are arranged in spheres called follicles of different sizes, in which most of the iodine in the body concentrates. For dose assessment in follicles, it is necessary to consider specific emissions of iodine isotopes in the calculation. Hence, the aim of this work was to evaluate the contribution of 131 I and short-lived iodines to the absorbed dose in thyroid cells. Thus, the interaction of emissions from isotopes with follicles was carried out using the MCNP4C code. The results showed that the contribution of short-lived iodines for absorbed dose per disintegration is about 70%.
To model water flow and solute transport in soils, hydrodynamic and hydrodispersive parameters ar... more To model water flow and solute transport in soils, hydrodynamic and hydrodispersive parameters are required as input data in the mathematical models. This work aims to estimate the soil hydraulic and solute transport properties using a ponded axisymmetric infiltration experiment using a single-ring infiltrometer along with a conservative tracer (Cl-) in the field. Single ring infiltration experiments were accomplished on an Oxisol in Areia in the state of Paraíba, Brazil (6o 58' S, 35o 41' W, and 645 m), in a 50 x 50 m grid (16 points). The unsaturated hydraulic conductivity (K) and the sorptivity (S) were estimated for short or long time analysis of cumulative three-dimensional infiltration. The single tracer technique was used to calculate mobile water fraction (Ф) by measuring the solute concentration underneath the ring infiltrometer at the end of the infiltration. Two solute transfer numerical models based on the mobile-immobile water concept were used. The mobile water...
The present commercial softwares, used for image processing in Biodosimetry, are mostly expensive... more The present commercial softwares, used for image processing in Biodosimetry, are mostly expensive and developed in dedicated systems, and they may not be adapted for microscopes of routine laboratory. The aim of this study was to report the prototype software developed at the Laboratorio de Modelagem e Biodosimetria Aplicada, and as well, highlight the influence of the quality of chromosome preparations in image processing for Cytogenetic dosimetry. The prototype application includes filters for noise reduction, contrast enhancement techniques, segmentation based on gray levels combined with morphological operators, interactive tools for separating chromosomes and access to a database, providing resources for pattern recognition.The influence of cytogenetic procedures was evaluated in 19 metaphases of peripheral blood lymphocytes, divided into three criteria: clear, with little or no overlap and without overlapping chromatids; excessive contraction of chromosomes; chromosome not uni...
In Positron Emission Tomography (PET), health staff is exposed to 511-keV photons, which is a res... more In Positron Emission Tomography (PET), health staff is exposed to 511-keV photons, which is a result of the positron annihilation process. This energy is about four times greater than the 140 keV commonly found in studies based on Single Photon Emission Computed Tomography (SPECT). Besides this different level of energy, 0.5 mm lead-equivalent aprons have being used either in SPECT or PET procedures. In this context, this work was designed for evaluating the effectiveness of such aprons in individual radioprotection of health professionals involved in Positron Emission Tomography. For this, by using MCNP4C-based Monte Carlo simulations, the average energy delivered per particle to the regions corresponding to operational quantities Hp(10) and Hp(0.07) were calculated for two conditions of individual exposures: wearing and not wearing a 0.05 mm lead-equivalent apron. The results obtained pointed out that Hp(10) has similar value in both situations. On the other hand, for the region c...
The theory of fractals, proposed by the mathematician Mandelbrot (1975), has been applied to many... more The theory of fractals, proposed by the mathematician Mandelbrot (1975), has been applied to many fields in Biology, mainly due to the property of self-similarity observed in the natural world, such as in the DNA molecule and chromatin structure. Many researches have proven the applicability of this mathematical analysis for the identification of cells containing mutations, in the case of cancers, or due to exposures to chemicals and ultraviolet radiation, but until the present moment, no work was done with ionizing radiation. The aim of the present study was to investigate the use of fractal analysis for the identification of irradiated cells, and to discuss its potential use as an indicator of human exposures to ionizing radiation. For this, 200 cells were digitalized, where 100 were from a blood sample irradiated with an absorbed dose of 3 Gy of gamma radiation, and 100cells were non-irradiated. Fractal dimensions (FD) were calculated by the method of Box-Counting. It was possibl...
Among the radiotherapeutics' modalities, total body irradiation (TBI) is used as treatment for ce... more Among the radiotherapeutics' modalities, total body irradiation (TBI) is used as treatment for certain hematological, oncological and immunological diseases. The aim of this study was to evaluate the long-term effects of low-dose TBI on plasma concentration of total protein and albumin using prematurely and undernourished rats as animal model. For this, four groups with 9 animals each were formed: Normal nourished (N); Malnourished (M); Irradiated Normal nourished (IN); Irradiated Malnourished (IM). At the age of 28 days, rats of the IN and IM groups underwent total body gamma irradiation with a source of cobalt-60. Total protein and Albumin in the blood serum was quantified by colorimetry. This research indicates that procedures involving low-dose total body irradiation in children have repercussions in the reduction in body-mass as well as in the plasma levels of total protein and albumin. Our findings reinforce the periodic monitoring of total serum protein and albumin levels as an important tool in long-term follow-up of pediatric patients in treatments associated to total body irradiation.
Brazilian Journal of Medical and Biological Research, 2015
Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological... more Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates.
Os transtornos de ansiedade são as alterações de saúde mental mais prevalentes no mundo, com grav... more Os transtornos de ansiedade são as alterações de saúde mental mais prevalentes no mundo, com graves implicações sociais e econômicas, representando um grande desafio na gestão de saúde pública. Na busca de soluções inovadoras, tem crescido o interesse pelo uso das tecnologias digitais como ferramenta para promoção da saúde mental. Neste contexto, esta pesquisa teve como objetivo prospectar a evolução de dados patentários de tecnologias digitais, utilizadas no apoio ao tratamento de transtornos de ansiedade, depositadas nos últimos 20 anos. Para tanto, utilizou-se a ferramenta Orbit® Intelligence, tendo sido encontrados 312 documentos. Este estudo evidenciou a Realidade Virtual como interface de escolha entre usuário e computador nas tecnologias presentes nesses registros, sendo os EUA o maior detentor dessas patentes. Nenhum registro, envolvendo essas tecnologias para tratamento de ansiedade, teve origem no Brasil, mesmo este sendo considerado o país com a maior taxa de indivíduos c...
Brazilian Archives of Biology and Technology, 2005
The increase in ionizing radiation (IR) applications, especially nuclear, has been followed by th... more The increase in ionizing radiation (IR) applications, especially nuclear, has been followed by the growth of public concern for the potential associated risks. The public’s perception of such risks is often based on the philosophy that IR is harmful at any exposure level. On the other hand, although radiation workers have knowledge about the nature of IR and its potential health effects, the relationship between absorbed dose and risk is not well understood, principally for low doses. This report presents an overview of physical and biological dosimetry as complementary methodologies, as well as their possible contribution for improving risk perception in radioprotection.
Weeds are responsible for losses in sugarcane productivity, often requiring the application of he... more Weeds are responsible for losses in sugarcane productivity, often requiring the application of herbicides to control their infestation in crops. One of the herbicides commonly used in sugarcane cultivation is Imazapic. However, this chemical can be leached into environmental compartments when applied to soil, contaminating it. Scientific research has shown that the soil amended with biochar can reduce the leaching of herbicides, avoiding environmental pollution. Therefore, the present work aimed to evaluate the adsorption efficiency of Imazapic in a dystrophic Yellow Ultisol amended with biochar cultivated with sugarcane. Biochars were produced with sugarcane bagasse by pyrolysis at temperatures of 300, 500, and 700ºC to evaluate the adsorption capacity of Imazapic by the soil amended with biochar. The experiments revealed an increase in Imazapic adsorption with soil amended with biochar and that the adsorptive potential is more significant for pyrolyzed biochars at higher temperatu...
This work evaluated the genetic damage in descendants of male pupae of Aedes (Stegomyia) aegypti ... more This work evaluated the genetic damage in descendants of male pupae of Aedes (Stegomyia) aegypti (Diptera: Culicidae) separately exposed to 20, 30, and 40 Gy of gamma radiation in the context of Sterile Insect Technique (SIT). Despite the transmission of the dominant lethal mutation, the employed dose levels did not promote a marked reduction in adult mosquito emergence and fertility. This study emphasized that semi-sterilizing doses < 50 Gy for SIT of Aedes aegypti are not recommended.
Evaluation of thyroid uptake, by administration of small activities of radioactive iodine (I or I... more Evaluation of thyroid uptake, by administration of small activities of radioactive iodine (I or I), is a well-defined procedure. Nowadays, nuclear medicine departments are using scintillation cameras coupled to pinhole collimators to perform such studies. On the other hand, gamma probes, which are normally used in radioguided surgical procedures, can technically be used for measuring the thyroid uptake of radioiodine. In this context, the aim of this work is to evaluate the potential use of surgical gamma probe as an alternative method for thyroid uptake measurements. Primarily, studies of feasibility were performed to quantify the efficiency of gamma probe and to compare it with the scintillation camera one. Henceforth, measurements were carried out with a group of 12 patients undergoing 24 hours thyroid function study, after oral administration of I. Thyroid uptake was obtained by scintillation camera (AXIS Picker equipped with a pinhole collimator) according to the protocol of th...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The concept of gray water footprint (GWF) was introduced as an indicator of the volume of freshwa... more The concept of gray water footprint (GWF) was introduced as an indicator of the volume of freshwater required to dilute the total pollutant load, generated from a particular production process, to maintain water quality standards. In crop production, for example, the theoretical calculation of the GWF can be employed as a sound tool for assessing the environmental impacts due to the use of pesticides. In this context, we compared two models for estimating the GWF of pesticide mixtures applied to the soil in a sugarcane crop, in Pernambuco, Brazil. One model was proposed by Hoekstra et al. (2011) and calculates the GWF based on the maximum concentration limit acceptable in water. The other one was designed by Paraiba et al. (2014) and employs the concept of Concentration Addition. This latter model also takes into account the effect of toxicity of pesticide mixtures on aquatic organisms and water quality, considering the characteristics of the soil and cultivation data obtained through the field and physical-chemical tests pesticides used in agricultural activities. The model of Paraiba et al. (2014) has shown to be more conservative in determining the GWF of the pesticide mixtures (2.00 Â 10 7 m 3 ha À1) in the aquatic ecosystem, than the model of Hoekstra et al. (2011) (6.25 Â 10 5 m 3 ha À1 for Sulfentrazone). The results presented and discussed in this study reinforce the use of the GWF as an indicator of water quality for agricultural sustainability. Our work also contributes to a better understanding of the advantages and limitations of each model approach in the assessment of the volume of freshwater needed to dilute the contaminant load in agriculture activities as, for instance, in sugarcane crops.
ABSTRACT Radiotherapy (RT) is an important treatment for cervical cancer. The quality of life of ... more ABSTRACT Radiotherapy (RT) is an important treatment for cervical cancer. The quality of life of patients undergoing RT may be compromised during and following treatment by nausea, diarrhea, vomiting, burns, erythema and fistula. Cytokinesis-block micronucleus (CBMN) assays may be useful for predicting adverse effects of RT for cancer. The CBMN test is easy to perform and is reproducible for screening subjects exposed to ionizing radiation. We investigated the use of the frequency of micronuclei (MN) from peripheral blood samples, irradiated in vitro, as a possible biomarker to predict the side effects of RT in patients with cervical cancer. We used 10 patients with cervical cancer receiving RT and chemotherapy. We found a strong relation between the frequency of MN and the appearance of acute side effects of RT for cervical cancer. We suggest that the methodology presented here may be useful for predicting side effects of RT for patients affected by cervical cancer and who have undergone chemotherapy.
La detection et la mesure de tres faibles niveaux de radioactivite correspondent a un besoin dans... more La detection et la mesure de tres faibles niveaux de radioactivite correspondent a un besoin dans de nombreux domaines, notamment en dosimetrie interne, dans le cadre des analyses radiotoxicologiques. Les methodes actuellement utilisees sont toutes fondees sur la detection des rayonnements. En ce qui concerne les actinides, les methodes reposent sur la mesure par spectrometrie alpha qui necessite une preparation des echantillons et un temps de comptage parfois tres long. Aujourd'hui, un grand nombre de recherches sont menees afin d'utiliser des methodes basees sur la spectrometrie de masse comme methodes, si non alternatives, au moins complementaires a la spectrometrie alpha. Dans cette etude, les performances de la spectrometrie de masse d'ions secondaires (sims) sont evaluees pour l'analyse de l'uranium, a l'etat de traces, dans des echantillons biologiques, et plus particulierement, dans des prelevements d'urine. La methode sims consiste a bombarder la surface d'un specimen avec un faisceau d'ions primaires. Les atomes des couches superficielles du specimen sont ainsi progressivement arraches, dont certains sous forme d'ions. Ces ions, appeles ions secondaires, sont ensuite analyses selon leur rapport masse sur charge. Compte tenu de son importance, l'etude debute par la recherche d'une methode de preparation des specimens adaptee au sims et egalement a la spectrometrie alpha, retenue comme methode de validation. L'utilisation de films polymeres, obtenus a partir d'un pyrrole fonctionnalise, dans lesquels l'uranium se fixe par echange ionique, s'est revelee adequate. Les essais avec les premiers specimens ainsi prepares montrent, d'une part, la sensibilite de la methode sims et, d'autre part, la possibilite d'obtenir des rapports isotopiques. La faisabilite de la methode demontree, l'etape suivante concerne l'utilisation d'un traceur pour quantifier l'uranium urinaire. Le choix s'est porte sur l'isotope #2#3#3u qui n'est que tres rarement present dans les cas d'exposition interne et dont la periode radioactive est compatible avec l'analyse par sims. Apres extraction de l'uranium contenu dans des echantillons d'urine et en appliquant le protocole etudie de preparation du specimen, la mesure par sims des rapports isotopiques #2#3#3u/#2#3#8u permet d'atteindre une limite de detection de 10#-#6 bq (10#-#10 g) en #2#3#8u par litre d'urine, pour un temps d'analyse de 5 minutes. Par ailleurs, au vu des resultats obtenus, quelques autres echantillons biologiques sont traites afin d'illustrer l'autre potentialite de la methode sims pour la recherche en dosimetrie interne, a savoir la microlocalisation analytique.
Differentiation of micronuclei (MN) caused by ionizing radiation from those caused by chemicals i... more Differentiation of micronuclei (MN) caused by ionizing radiation from those caused by chemicals is a crucial step for managing treatment of individuals exposed to radiation. MN in binucleated lymphocytes in peripheral blood are widely used as biomarkers for estimating dose of radiation, but they are not specific for ionizing radiation. MN induced by ionizing radiation originate predominantly as a result of chromosome breaks (clastogenic action), whereas MN caused by chemical agents are derived from the loss of entire chromosomes (aneugenic action). C-banding highlights centromeres, which might make it possible to distinguish radiation induced MN, i.e., as a byproduct of acentric fragments, from those caused by the loss of entire chromosomes. To test the use of C-banding for identifying radiation induced MN, a blood sample from a healthy donor was irradiated with 3 Gy of Co-60 gamma rays and cultured. Cells were harvested and dropped onto slides, divided into a group stained directly with Giemsa and another processed for C banding, then stained with Giemsa. The frequency of MN in 500 binucleated cells was scored for each method. In preparations stained with Giemsa directly, the MN appeared as uniformly stained structures, whereas after C banding, some MN exhibited darker regions corresponding to centromeres that indicated that they were not derived from acentric fragments. The C-banding technique enables differentiation of MN from acentric chromosomal material. This distinction is useful for improving the specificity of the MN assay as a biomarker for ionizing radiation.
Journal of Radioanalytical and Nuclear Chemistry, Sep 1, 2006
Thyroid cells are arranged in spheres called follicles of different sizes, in which most of the i... more Thyroid cells are arranged in spheres called follicles of different sizes, in which most of the iodine in the body concentrates. For dose assessment in follicles, it is necessary to consider specific emissions of iodine isotopes in the calculation. Hence, the aim of this work was to evaluate the contribution of 131 I and short-lived iodines to the absorbed dose in thyroid cells. Thus, the interaction of emissions from isotopes with follicles was carried out using the MCNP4C code. The results showed that the contribution of short-lived iodines for absorbed dose per disintegration is about 70%.
To model water flow and solute transport in soils, hydrodynamic and hydrodispersive parameters ar... more To model water flow and solute transport in soils, hydrodynamic and hydrodispersive parameters are required as input data in the mathematical models. This work aims to estimate the soil hydraulic and solute transport properties using a ponded axisymmetric infiltration experiment using a single-ring infiltrometer along with a conservative tracer (Cl-) in the field. Single ring infiltration experiments were accomplished on an Oxisol in Areia in the state of Paraíba, Brazil (6o 58' S, 35o 41' W, and 645 m), in a 50 x 50 m grid (16 points). The unsaturated hydraulic conductivity (K) and the sorptivity (S) were estimated for short or long time analysis of cumulative three-dimensional infiltration. The single tracer technique was used to calculate mobile water fraction (Ф) by measuring the solute concentration underneath the ring infiltrometer at the end of the infiltration. Two solute transfer numerical models based on the mobile-immobile water concept were used. The mobile water...
The present commercial softwares, used for image processing in Biodosimetry, are mostly expensive... more The present commercial softwares, used for image processing in Biodosimetry, are mostly expensive and developed in dedicated systems, and they may not be adapted for microscopes of routine laboratory. The aim of this study was to report the prototype software developed at the Laboratorio de Modelagem e Biodosimetria Aplicada, and as well, highlight the influence of the quality of chromosome preparations in image processing for Cytogenetic dosimetry. The prototype application includes filters for noise reduction, contrast enhancement techniques, segmentation based on gray levels combined with morphological operators, interactive tools for separating chromosomes and access to a database, providing resources for pattern recognition.The influence of cytogenetic procedures was evaluated in 19 metaphases of peripheral blood lymphocytes, divided into three criteria: clear, with little or no overlap and without overlapping chromatids; excessive contraction of chromosomes; chromosome not uni...
In Positron Emission Tomography (PET), health staff is exposed to 511-keV photons, which is a res... more In Positron Emission Tomography (PET), health staff is exposed to 511-keV photons, which is a result of the positron annihilation process. This energy is about four times greater than the 140 keV commonly found in studies based on Single Photon Emission Computed Tomography (SPECT). Besides this different level of energy, 0.5 mm lead-equivalent aprons have being used either in SPECT or PET procedures. In this context, this work was designed for evaluating the effectiveness of such aprons in individual radioprotection of health professionals involved in Positron Emission Tomography. For this, by using MCNP4C-based Monte Carlo simulations, the average energy delivered per particle to the regions corresponding to operational quantities Hp(10) and Hp(0.07) were calculated for two conditions of individual exposures: wearing and not wearing a 0.05 mm lead-equivalent apron. The results obtained pointed out that Hp(10) has similar value in both situations. On the other hand, for the region c...
The theory of fractals, proposed by the mathematician Mandelbrot (1975), has been applied to many... more The theory of fractals, proposed by the mathematician Mandelbrot (1975), has been applied to many fields in Biology, mainly due to the property of self-similarity observed in the natural world, such as in the DNA molecule and chromatin structure. Many researches have proven the applicability of this mathematical analysis for the identification of cells containing mutations, in the case of cancers, or due to exposures to chemicals and ultraviolet radiation, but until the present moment, no work was done with ionizing radiation. The aim of the present study was to investigate the use of fractal analysis for the identification of irradiated cells, and to discuss its potential use as an indicator of human exposures to ionizing radiation. For this, 200 cells were digitalized, where 100 were from a blood sample irradiated with an absorbed dose of 3 Gy of gamma radiation, and 100cells were non-irradiated. Fractal dimensions (FD) were calculated by the method of Box-Counting. It was possibl...
Among the radiotherapeutics' modalities, total body irradiation (TBI) is used as treatment for ce... more Among the radiotherapeutics' modalities, total body irradiation (TBI) is used as treatment for certain hematological, oncological and immunological diseases. The aim of this study was to evaluate the long-term effects of low-dose TBI on plasma concentration of total protein and albumin using prematurely and undernourished rats as animal model. For this, four groups with 9 animals each were formed: Normal nourished (N); Malnourished (M); Irradiated Normal nourished (IN); Irradiated Malnourished (IM). At the age of 28 days, rats of the IN and IM groups underwent total body gamma irradiation with a source of cobalt-60. Total protein and Albumin in the blood serum was quantified by colorimetry. This research indicates that procedures involving low-dose total body irradiation in children have repercussions in the reduction in body-mass as well as in the plasma levels of total protein and albumin. Our findings reinforce the periodic monitoring of total serum protein and albumin levels as an important tool in long-term follow-up of pediatric patients in treatments associated to total body irradiation.
Brazilian Journal of Medical and Biological Research, 2015
Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological... more Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates.
Os transtornos de ansiedade são as alterações de saúde mental mais prevalentes no mundo, com grav... more Os transtornos de ansiedade são as alterações de saúde mental mais prevalentes no mundo, com graves implicações sociais e econômicas, representando um grande desafio na gestão de saúde pública. Na busca de soluções inovadoras, tem crescido o interesse pelo uso das tecnologias digitais como ferramenta para promoção da saúde mental. Neste contexto, esta pesquisa teve como objetivo prospectar a evolução de dados patentários de tecnologias digitais, utilizadas no apoio ao tratamento de transtornos de ansiedade, depositadas nos últimos 20 anos. Para tanto, utilizou-se a ferramenta Orbit® Intelligence, tendo sido encontrados 312 documentos. Este estudo evidenciou a Realidade Virtual como interface de escolha entre usuário e computador nas tecnologias presentes nesses registros, sendo os EUA o maior detentor dessas patentes. Nenhum registro, envolvendo essas tecnologias para tratamento de ansiedade, teve origem no Brasil, mesmo este sendo considerado o país com a maior taxa de indivíduos c...
Brazilian Archives of Biology and Technology, 2005
The increase in ionizing radiation (IR) applications, especially nuclear, has been followed by th... more The increase in ionizing radiation (IR) applications, especially nuclear, has been followed by the growth of public concern for the potential associated risks. The public’s perception of such risks is often based on the philosophy that IR is harmful at any exposure level. On the other hand, although radiation workers have knowledge about the nature of IR and its potential health effects, the relationship between absorbed dose and risk is not well understood, principally for low doses. This report presents an overview of physical and biological dosimetry as complementary methodologies, as well as their possible contribution for improving risk perception in radioprotection.
Weeds are responsible for losses in sugarcane productivity, often requiring the application of he... more Weeds are responsible for losses in sugarcane productivity, often requiring the application of herbicides to control their infestation in crops. One of the herbicides commonly used in sugarcane cultivation is Imazapic. However, this chemical can be leached into environmental compartments when applied to soil, contaminating it. Scientific research has shown that the soil amended with biochar can reduce the leaching of herbicides, avoiding environmental pollution. Therefore, the present work aimed to evaluate the adsorption efficiency of Imazapic in a dystrophic Yellow Ultisol amended with biochar cultivated with sugarcane. Biochars were produced with sugarcane bagasse by pyrolysis at temperatures of 300, 500, and 700ºC to evaluate the adsorption capacity of Imazapic by the soil amended with biochar. The experiments revealed an increase in Imazapic adsorption with soil amended with biochar and that the adsorptive potential is more significant for pyrolyzed biochars at higher temperatu...
This work evaluated the genetic damage in descendants of male pupae of Aedes (Stegomyia) aegypti ... more This work evaluated the genetic damage in descendants of male pupae of Aedes (Stegomyia) aegypti (Diptera: Culicidae) separately exposed to 20, 30, and 40 Gy of gamma radiation in the context of Sterile Insect Technique (SIT). Despite the transmission of the dominant lethal mutation, the employed dose levels did not promote a marked reduction in adult mosquito emergence and fertility. This study emphasized that semi-sterilizing doses < 50 Gy for SIT of Aedes aegypti are not recommended.
Evaluation of thyroid uptake, by administration of small activities of radioactive iodine (I or I... more Evaluation of thyroid uptake, by administration of small activities of radioactive iodine (I or I), is a well-defined procedure. Nowadays, nuclear medicine departments are using scintillation cameras coupled to pinhole collimators to perform such studies. On the other hand, gamma probes, which are normally used in radioguided surgical procedures, can technically be used for measuring the thyroid uptake of radioiodine. In this context, the aim of this work is to evaluate the potential use of surgical gamma probe as an alternative method for thyroid uptake measurements. Primarily, studies of feasibility were performed to quantify the efficiency of gamma probe and to compare it with the scintillation camera one. Henceforth, measurements were carried out with a group of 12 patients undergoing 24 hours thyroid function study, after oral administration of I. Thyroid uptake was obtained by scintillation camera (AXIS Picker equipped with a pinhole collimator) according to the protocol of th...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The concept of gray water footprint (GWF) was introduced as an indicator of the volume of freshwa... more The concept of gray water footprint (GWF) was introduced as an indicator of the volume of freshwater required to dilute the total pollutant load, generated from a particular production process, to maintain water quality standards. In crop production, for example, the theoretical calculation of the GWF can be employed as a sound tool for assessing the environmental impacts due to the use of pesticides. In this context, we compared two models for estimating the GWF of pesticide mixtures applied to the soil in a sugarcane crop, in Pernambuco, Brazil. One model was proposed by Hoekstra et al. (2011) and calculates the GWF based on the maximum concentration limit acceptable in water. The other one was designed by Paraiba et al. (2014) and employs the concept of Concentration Addition. This latter model also takes into account the effect of toxicity of pesticide mixtures on aquatic organisms and water quality, considering the characteristics of the soil and cultivation data obtained through the field and physical-chemical tests pesticides used in agricultural activities. The model of Paraiba et al. (2014) has shown to be more conservative in determining the GWF of the pesticide mixtures (2.00 Â 10 7 m 3 ha À1) in the aquatic ecosystem, than the model of Hoekstra et al. (2011) (6.25 Â 10 5 m 3 ha À1 for Sulfentrazone). The results presented and discussed in this study reinforce the use of the GWF as an indicator of water quality for agricultural sustainability. Our work also contributes to a better understanding of the advantages and limitations of each model approach in the assessment of the volume of freshwater needed to dilute the contaminant load in agriculture activities as, for instance, in sugarcane crops.
ABSTRACT Radiotherapy (RT) is an important treatment for cervical cancer. The quality of life of ... more ABSTRACT Radiotherapy (RT) is an important treatment for cervical cancer. The quality of life of patients undergoing RT may be compromised during and following treatment by nausea, diarrhea, vomiting, burns, erythema and fistula. Cytokinesis-block micronucleus (CBMN) assays may be useful for predicting adverse effects of RT for cancer. The CBMN test is easy to perform and is reproducible for screening subjects exposed to ionizing radiation. We investigated the use of the frequency of micronuclei (MN) from peripheral blood samples, irradiated in vitro, as a possible biomarker to predict the side effects of RT in patients with cervical cancer. We used 10 patients with cervical cancer receiving RT and chemotherapy. We found a strong relation between the frequency of MN and the appearance of acute side effects of RT for cervical cancer. We suggest that the methodology presented here may be useful for predicting side effects of RT for patients affected by cervical cancer and who have undergone chemotherapy.
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Papers by Ademir Amaral