Mitiko Saiki

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Papers by Mitiko Saiki

Comparative analysis of newborn and adult Bothrops jararaca snake venoms

Toxicon, 2010

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Validation and Application of Plants as Biomonitors of Trace Element Atmospheric Pollution – A Co-Ordinated Effort in 14 Countries

Journal of Atmospheric Chemistry, 2004

The International Atomic Energy Agency (IAEA) organized a co-ordinated research project (CRP) on ... more The International Atomic Energy Agency (IAEA) organized a co-ordinated research project (CRP) on "Validation and application of plants as biomonitors of trace element atmospheric pollution analysed by nuclear and related techniques" involving 14 participating countries. The CRP's objective was to identify appropriate bioindicators for local and/or regional application and validate them for general air pollution monitoring. Activities included quantification studies, research into spatial and time resolution for particular organisms, and physiological studies. A number of suitable bioindicators were identified in different parts of the globe and tested during the CRP. Sampling strategies were reviewed and the recommended approach adopted by the group. Appropriate sample preparation procedures were assessed and harmonised to the degree allowed by different geographic and climatic conditions in the participating countries. Two interlaboratory comparison exercises were carried out on lichen and moss materials. Results confirmed definite improvement in analytical performance of the participating laboratories, but also revealed possible inconsistencies due to different sample processing procedures. Several monitoring surveys were carried out and consequently pollution maps drawn for extended areas or countries. Overall results confirmed applicability of lower plants for assessing the degree of atmospheric pollution and provided several countries with effective monitoring tools not used before.

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Activation Analysis Methods and Applications

Journal of Radioanalytical and Nuclear Chemistry, 2005

Summary Rib bones of Brazilian people were analyzed by neutron activation analysis to evaluate e... more Summary Rib bones of Brazilian people were analyzed by neutron activation analysis to evaluate element composition. Freeze-dried cortical and trabecular tissues, separately, and calcinated total rib tissues were analyzed. The concentrations of the Ba, Br, Ca, Cl, Fe, K, Mg, Mn, Na, P, Rb, Sr, and Zn elements were determined. Comparisons between the results obtained in cortical and trabecular bones indicated significant differences in the concentration for several elements. Results obtained in cortical and trabecular bones were also compared with literature values.

Initial enamel wear of glazed and polished leucite-based porcelains with different fusing temperatures

General dentistry

This study used the radiotracer method to measure the initial enamel wear caused by low- and high... more This study used the radiotracer method to measure the initial enamel wear caused by low- and high-fusing porcelains after glazing or polishing. It also tested the correlation between enamel wear and porcelain surface roughness (Ra). Surface morphology was assessed by optical microscopy. Cylindrical specimens of three porcelains (two high-fusing, one low-fusing) were either autoglazed or polished. Flattened enamel specimens were irradiated with neutrons and submitted to the wear assay for 2,500 cycles in distilled water using a 285 g load; the released beta 32P particles were measured for 10 minutes. For all samples, Ra was recorded with a profilometer before and after testing. Enamel wear was not significantly different for porcelain or finishing method but there was a trend of interaction between the two variables (p = 0.08). A positive correlation was found between enamel wear and the initial Ra of porcelain (r = 0.71). The glazed surfaces of high-fusing porcelains were wavy and h...

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A study on trace elements in fingernails and toenails from adult individuals by instrumental neutron activation analysis

Brazilian Journal of Radiation Sciences, 2020

This study presents results of instrumental neutron activation analysis (INAA) of nails from heal... more This study presents results of instrumental neutron activation analysis (INAA) of nails from healthy adult individuals living in São Paulo city, Brazil. Concentrations of As, Br, Ca, Co, Cr, Fe, K, La, Na, Sb, Se and Zn were determined in fingernails and toenails and their variations with gender, age, body mass index among individuals and inter-element correlations were evaluated. These results indicated that several factors might affect in the nail element composition. In addition, there are few published data for finger and toenails analyses. However, comparisons made between the concentrations of elements obtained in fingernails were reasonable within the range of literature values. The findings of this study may contribute to establish an appropriate protocol to obtain data of nail element composition to be used as reference values.

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Accumulation of trace element content in the lungs of Sao Paulo city residents and its correlation to lifetime exposure to air pollution

Heavy metals are natural and essential elements of the environment and living beings, produced fr... more Heavy metals are natural and essential elements of the environment and living beings, produced from natural (e.g. volcanic activity and cosmic ray-induced spallation) and anthropogenic processes (e.g. industrial and fossil fuel combustion). Studies showed increase of heavy metal and Polonium-210 concentrations in lung autopsies linked to urban and industrial air pollution. In this preliminary study, we analyzed the levels of heavy metals and Polonium-210 (210Po) in lung tissues in autopsies from residents of the city of Sao Paulo, SP, Brazil. In order to identify the generating sources of the heavy metals in lung a factor analysis was performed. Of the first four factors, which explain 66% of the total variability, three were associated with vehicular sources. The fitting of a regression model with Polonium-210 as the response variable and with the four factors as explanatory variables, controlling for age, sex and tobacco, showed a significant association between the concentration ...

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Evaluation of the uncertainty associated with sample holders in NAA measurements in LAN/IPEN

Brazilian Journal of Radiation Sciences, 2019

In IPEN’s Neutron Activation Laboratory (LAN/IPEN), thin stainless steel sample holders are used ... more In IPEN’s Neutron Activation Laboratory (LAN/IPEN), thin stainless steel sample holders are used for gamma spectrometry in NAA measurements. This material is very practical, but its chemical composition may be troublesome, as it presents large amounts of elements with intermediate atomic number, with attenuation factors for low-energy gamma-rays that must not be neglected. In this study, count rates obtained using different sample holders were compared. To accomplish that, an Am-241 source, with 59-keV gamma emission, was used so that low-energy gamma attenuation differences can be determined. Moreover, in order to study the energy dependence of these differences, a Ho-166m source was also used. From these results, it was possible to analyze the experimental error associated to the variations between sample holders, with the aim of introducing an addictive term to the uncertainty analysis of comparative Neutron Activation Analysis results.

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Low dose of chlorine exposure exacerbates nasal and pulmonary allergic inflammation in mice

Scientific reports, Jan 22, 2018

Work-exacerbated asthma (WEA) is defined as preexisting asthma that worsens with exposure to irri... more Work-exacerbated asthma (WEA) is defined as preexisting asthma that worsens with exposure to irritants [e.g., chlorine (Cl) derivatives] in the workplace. The maximum allowable concentration in the workplace of Cl exposure is 3 mg/ m (described in OSHA). We investigated in an experimental asthma model in mice the effects of a single exposure to a sodium hypochlorite dose with this allowed chlorine concentration and a tenfold higher dose. Acute chlorine exposure at 3.3 mg/m in the OVA-sensitized group increased eosinophils in the peribronquial infiltrate, cytokine production, nasal mucus production and the number of iNOS positive cells in the distal lung compared to only sensitized mice. The exposure to a higher dose of 33.3 mg/m in the OVA-sensitized group resulted in an increase in respiratory system elastance, in the total and differential numbers of inflammatory cells in bronchoalveolar lavage fluid, IL-4, IL-5, and IL-17 in the lungs, eosinophils in peribronquial infiltrate and ...

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A Streamlined Approach by a Combination of Bioindication and Geostatistical Methods for Assessing Air Contaminants and Their Effects on Human Health in Industrialized Areas: A Case Study in Southern Brazil

Frontiers in Plant Science, 2017

Air Quality Assessment Combining Alternative Methods These data are public and may be accessed on... more Air Quality Assessment Combining Alternative Methods These data are public and may be accessed on the website of the the Brazilian Ministry of Health. Significant associations were found between the health data and refinery activities. The combination of the spatial characterization of air pollution and clinical health data revealed that adverse effects were significant for individuals over 38 years of age. These results also suggest that a protocol designed to monitor urban air quality may be an effective and low-cost strategy in environmentally contaminated cities, especially in low-and middle-income countries.

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Biomonitoring of genotoxic effects and elemental accumulation derived from air pollution in community urban gardens

The Science of the total environment, 2017

Urban gardening is a growing global phenomenon with a positive impact on society. Despite several... more Urban gardening is a growing global phenomenon with a positive impact on society. Despite several associated benefits, growing vegetables in urban gardens that are localized in highly polluted areas poses questions about the safety of the produced food. Therefore, the identification of risk factors that result in possible deleterious effects to human health is important for realizing all of the benefits to society. We evaluated the use of two biomonitoring methods in ten urban gardens of Sao Paulo city and one control site: the micronuclei frequencies for early tetrads of Tradescantia pallida (Rose) Hunt. cv. "Purpurea" Boom (hereafter, Trad-MCN) as a short-term indicator of genotoxic response and tree barks to quantify the accumulation of traffic-related chemical elements as a long-term biomarker of air pollution in urban gardens. Mature plants of Tradescantia pallida were exposed in each garden, and their inflorescences were sampled over three months. A random set of 300...

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The influence of atmospheric particles on the elemental content of vegetables in urban gardens of Sao Paulo, Brazil

Environmental Pollution, 2016

Although urban horticulture provides multiple benefits to society, the extent to which these vege... more Although urban horticulture provides multiple benefits to society, the extent to which these vegetables are contaminated by the absorption of chemical elements derived from atmospheric deposition is unclear. This study was designed to evaluate the influence of air pollution on leafy vegetables in community gardens of Sao Paulo, Brazil. Vegetable seedlings of Brassica oleracea var. acephala (collard greens) and Spinacia oleracea (spinach) obtained in a non-polluted rural area and growing in vessels containing standard uncontaminated soil were exposed for three consecutive periods of 30, 60 and 90 days in 10 community gardens in Sao Paulo and in one control site. The concentrations of 17 chemical elements (traffic-related elements and those essential to plant biology) were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Tillandsia usneoides L. specimens were used as air plant biomonitors. The concentrations of As, Cd, Cr and Pb found in vegetables were compared to the recommended values for consumption. Principal Component Analysis (PCA) was used to cluster the elemental concentrations, and Generalized Linear Models (GLMs) were employed to evaluate the association of the factor scores from each PCA component with variables such as local weather, traffic burden and vertical barriers adjacent to the gardens. We found significant differences in the elemental concentrations of the vegetables in the different community gardens. These differences were related to the overall traffic burden, vertical obstacles and local weather. The Pb and Cd concentrations in both vegetables exceeded the limit values for consumption after 60 days of exposure. A strong correlation was observed between the concentration of traffic-related elements in vegetables and in Tillandsia usneoides L. An exposure response was observed between traffic burden and traffic-derived particles absorbed in the vegetables. Traffic-derived air pollution directly influences the absorption of chemical elements in leafy vegetables, and the levels of these elements may exceed the recommended values for consumption.

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Correlation study of air pollution and cardio-respiratory diseases through NAA of an atmospheric pollutant biomonitor

Journal of Radioanalytical and Nuclear Chemistry, 2013

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Caracterização de Polímeros e Determinação de Constituintes Inorgânicos em Embalagens Plásticas Metalizadas

Polímeros, 2002

Este trabalho apresenta os resultados analíticos da determinação de elementos químicos em materia... more Este trabalho apresenta os resultados analíticos da determinação de elementos químicos em materiais plásticos metalizados, obtidos por análise por ativação com nêutrons (NAA) e os resultados da identificação de polímeros por espectroscopia no infravermelho (IR) e calorimetria exploratória diferencial (DSC). Foram coletadas amostras de plásticos metalizados de embalagens de alimentos e cosméticos. Os resultados dos testes IR e DSC indicaram que os tipos de polímeros usados em plásticos metalizados são polietileno, polipropileno, poli(tereftalato de etileno) e poliestireno. A NAA consistiu em irradiar as amostras e padrões com fluxo de nêutrons térmicos do reator nuclear IEA-R1, seguido da medida da atividade dos raios gama induzidos usando um detector de Germânio hiperpuro acoplado ao espectrômetro de raios gama. Elementos tóxicos como arsênio, cádmio, cromo, níquel e antimônio assim como elementos não tóxicos como bário, cálcio, cobalto, ferro, escândio, selênio e zinco foram determ...

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Acúmulo de minerais em Aechmea blanchetiana (Baker) L.B. Smith (Bromeliaceae), contaminadas com zinco em cultivo in vitro

Hoehnea, 2012

Accumulation of mineral nutrients in Aechmea blanchetiana (Baker) L.B. Smith (Bromeliaceae) conta... more Accumulation of mineral nutrients in Aechmea blanchetiana (Baker) L.B. Smith (Bromeliaceae) contaminated with zinc during in vitro culture). The aim of this work was to evaluate the absorption and translocation of Ca, Co, Fe, K and Zn in plants of Aechmea blanchetiana grown in in vitro conditions contaminated with Zn (0.0, 0.18, 1.8, 18 and 180 mg Zn L-1). After 16 weeks of in vitro culture, root and shoot systems (leaves and stem) were separated, dried for dry mass measurements and neutron activation analysis (NAA). The results showed that the relative standard deviations were 9.1 % and errors were less than 12.9 %. The results obtained for A. blanchetiana indicated that Zn altered the absorption and translocation of Ca, Co, Fe, K and Zn. The species showed high values of zinc in root and aerial systems possibly indicating bioaccumulation of the element.

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Avaliação da Qualidade da Sinvastatina Comercializada por Farmácias de Manipulação em Belo Horizonte/MG

Vigilância Sanitária em Debate, 2014

A enorme expansão recente do setor de farmácias magistrais associada aos relatos de desvios na qu... more A enorme expansão recente do setor de farmácias magistrais associada aos relatos de desvios na qualidade de medicamentos manipulados, com casos graves, têm sido motivo de atenção por parte dos sistemas de Vigilância Sanitária no País. Com esse objetivo, tem-se buscado um monitoramento mais eficiente do trabalho das farmácias magistrais e dos produtos ofertados à população. Neste trabalho, foram avaliadas amostras de sinvastatina comercializadas em cinco diferentes farmácias de Belo Horizonte/Mg. Para cada estabelecimento, foram adquiridos via receita médica dois lotes do produto e realizadas as análises de: determinação de peso, identificação e teor de princípio ativo e uniformidade de doses unitárias. os resultados obtidos expressaram um índice de satisfatoriedade de apenas 30% do total de amostras manipuladas. Foi investigada também, pela técnica de análise por ativação neutrônica, a presença e concentração de impurezas inorgânicas presentes nas amostras. Mesmo em baixas concentrações, a presença de elementos não essenciais, como As, Br e Cr, pode ser prejudicial à saúde humana se consumidos de forma constante durante longo prazo. Esses resultados confirmam a necessidade de ações rápidas e eficientes pelas autoridades sanitárias para garantir a qualidade necessária a esses produtos.

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Acute Cardiopulmonary Alterations Induced by Fine Particulate Matter of São Paulo, Brazil

Toxicological Sciences, 2005

The mechanisms involved in the association between air pollution and increased cardiovascular mor... more The mechanisms involved in the association between air pollution and increased cardiovascular morbidity are not fully understood. The objective of this study was to test the hypothesis that fine particulate matter (PM 2.5) induces systemic inflammation and vasoconstriction of small arteries in the lung and heart of rats. Thirty-eight healthy Wistar rats were anesthetized, intubated, and submitted to the instillation of 1 ml of distilled water diluted in the following solution: blank filter, 100 mg and 500 mg of PM 2.5. PM 2.5 was collected in glass fiber filters with a high-volume sampler. The animals were sacrificed 24 h after instillation when blood, heart, and lung samples were collected for morphological and wet-to-dry weight ratio analysis. PM 2.5 consisted of the following elements: sulphur, arsenic, bromine, chlorine, cobalt, iron, lanthanum, manganese, antimony, scandium, and thorium. Total reticulocytes significantly increased at both PM 2.5 doses (p < 0.05) while hematocrit levels increased in the 500 mg group (p < 0.05). Quantification of segmented neutrophils and fibrinogen levels showed a significant decrease, while lymphocytes counting increased with 100 mg of PM 2.5 (p < 0.05). A significant dosedependent decrease of intra-acinar pulmonary arteriole lumen/wall ratio (L/W) was observed in PM groups (p < 0.001). Peribronchiolar arterioles L/W showed a significant decrease in the 500 mg group (p < 0.001). A significant increase in heart wet-to-dry weight ratio was observed in the 500 mg group (p < 0.001). In conclusion, fine environment particles in the city of São Paulo promote pulmonary and cardiac histological alterations. Pulmonary vasculature was markedly affected by particle instillation, resulting in significant vasoconstriction in healthy rats.

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Determinação de paládio em amostras biológicas aplicando técnicas analíticas nucleares

Química Nova, 2008

This study presents Pd determinations in bovine tissue samples containing palladium prepared in t... more This study presents Pd determinations in bovine tissue samples containing palladium prepared in the laboratory, and CCQM-P63 automotive catalyst materials of the Proficiency Test, using instrumental thermal and epithermal neutron activation analysis and energy dispersive X-ray fluorescence techniques. Solvent extraction and solid phase extraction procedures were also applied to separate Pd from interfering elements before the irradiation in the nuclear reactor. The results obtained by different techniques were compared against each other to examine sensitivity, precision and accuracy.

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Study on Element Migration from Plastic Food Packagings to Simulating Solutions

Macromolecular Symposia, 2006

In the present study a radiometric method was established for element migration determination fro... more In the present study a radiometric method was established for element migration determination from plastic food packagings to simulating solutions of 3% acetic acid solution and of water. This radiometric method consisted in irradiating plastics with neutrons, followed by exposition for migration and measurement the radioactivity in food-simulating solution. The experimental conditions used were 10 days of exposure at 40 8C. The migration was studied for packagings of water and dairy products. The results indicated the migration of Co, Cr and Sb to the simulating solutions. The advantages of this methodology are no necessity of blank analysis, as well as the use of high purity simulants. Moreover, it is possible to evaluate the migration to the food contents, instead of simulants. The detection limits of migration indicated the high sensitivity of the radiometric method.

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Trace element contents in serum of healthy elderly population of metropolitan São Paulo area in Brazil

Journal of Trace Elements in Medicine and Biology, 2007

In this study, the elements Br, Ca, Cl, Fe, Na, Rb, Se and Zn were determined in serum of a healt... more In this study, the elements Br, Ca, Cl, Fe, Na, Rb, Se and Zn were determined in serum of a healthy elderly population residing in the Sa˜o Paulo Metropolitan area, using instrumental neutron activation analysis. Comparison studies indicated that only Se concentration was significantly lower in the elderly group aged 75-91 years than those obtained for the group aged 60-74 years. Between genders, males presented lower Br concentrations and, the females lower Fe. Mean concentrations obtained for most elements were within the values reported in the literature.

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Tradescantia pallida cv. purpurea Boom in the Characterization of Air Pollution by Accumulation of Trace Elements

Journal of the Air & Waste Management Association, 2003

Tradescantia pallida cv. purpurea, a plant species widely employed for ornamentation in Brazil, h... more Tradescantia pallida cv. purpurea, a plant species widely employed for ornamentation in Brazil, has been successfully used for monitoring the genotoxicity of various agents by the micronucleus assay. To amplify knowledge about its suitability as a bioindicator species, its capacity for accumulating trace elements from urban air pollution was evaluated. T. pallida was rooted using standardized soil, and the vases were distributed in two highly polluted sites of the urban area of Sao Paulo, Brazil (Cerqueira Cesar and Congonhas districts), and in one unpolluted control site situated approximately 50 km from downtown Sao Paulo (in Caucaia do Alto). Approximately six months after exposure to pollutants, adult leaves of this plant were collected monthly for 12 months. The leaves were washed with deionized water, dried, and ground for analyses. Characterization of element levels was carried out by neutron activation analysis. Powdered samples and standards were irradiated at the IEA-RI nuclear reactor for short and long periods, and concentrations of As,

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