Dentre as diversas formas de se tratar o câncer de próstata, a braquiterapia com sementes de iodo-125 é uma opção que apresenta ótimos resultados e menor ocorrência de efeito colateral. No presente trabalho diferentes métodos de deposição de iodo radioativo em substrato de prata foram comparados com o propósito de eleger a alternativa mais adequada para a produção rotineira de sementes de iodo-125 do IPEN. A metodologia utilizada foi escolhida com base na infraestrutura disponível e na experiência dos pesquisadores presentes. Por essa razão, utilizou-se o iodo-131 para realização dos testes (mesmo comportamento do iodo-125). Quatro métodos foram selecionados: Método 1 (teste de eletrodeposição baseado no método desenvolvido por D. Kubiatowicz) com a eficiência de 65,16%; Método 2 (Reação química baseada no método desenvolvido por D. Kubiatowicz - HCl) com o resultado de 70,80% de eficiência; Método 3 (Reação química baseada no método desenvolvido pela Dra Maria Elisa Rostelato aquecimento/sulfeto) com 55,80% de eficiência; Método 4 (IQ-IPEN) apresentou o melhor resultado de eficiência, 99%. Como há mais fixação do material radioativo (que representa praticamente todo o custo da semente) por esse método, o preço final é o mais barato, sendo esse o método sugerido para ser implementado no laboratório de produção de fontes de braquiterapia do IPEN. Além disso o método é o mais rápido. / Among the different ways to treat prostate cancer, brachytherapy with iodine- 125 seeds is an option that provides good results and fewer side effects. In the present study several deposition methods of radioactive iodine in a silver substrate were compared in order to choose the most suitable alternative for the routine production to be implemented at IPENs laboratory. The methodology used was chosen based on the available infrastructure and experience of the researchers present. Therefore, the I131 was used for testing (same chemical behavior as I131). Four methods were selected: Method 1 (test based on electrodeposition method developed by D.Kubiatowicz) presented 65.16% efficiency; Method 2 (chemical reaction based on the method developed by D. Kubiatowicz - HCl) with the result of 70.80% efficiency; method 3 (chemical reaction based on the method developed by Dr. Maria Elisa Rostelato) with 55.80% efficiency; Method 4 (IQ-IPEN) resulted in 99% efficiency. Since this method has more radioactive material fixation (which represents virtually the entire cost of the seed), the final price is the cheapest. This method is the suggested one to be implemented in the IPENs laboratory for brachytherapy sources production. Besides, the method is the fasted one.

This reseach firstly investigated iodine-induced apoptotic effects and the underlying mechanism in thyroid cancer cells. Results indicated that apoptosis induced by iodine, especially at high dose of iodine (100 muM), was mitochondrial-mediated, with the loss of mitochondrial membrane potential, Bak up-regulation, caspase 3 activation and cytochrome C release from mitochondria. Iodine treatment decreased the level of mutant p53 including the R273H mutant that possesses anti-apoptotic features while increased the p21 level. The block of p21 significantly prevented iodine-induced apoptosis. High doses of iodine also stimulated the transient activation of the subfamily members of MAPKs (ERK1/2, p38 and JNK1/2). The results showed the three subfamily members of MAPKs all worked as anti-apoptotic factors. Surprisingly, high doses of iodine promoted instead of suppressed the expression of anti-apoptotic protein Bcl-xL expression. The increase of Bc1-xL was likely to compensate the damage induced by iodine since the inhibition of Bc1-xL accelerated iodine-mediated apoptosis. Collectively, iodine induced mitochondrial-mediated apoptosis in thyroid cancer cells. This apoptotic pathway was involved in the activation of MAPKs pathways, which may subsequently up-regulate p21, Bc1-xL, and down-regulate anti-apoptotic mutant p53 expression. The findings provide solid molecular evidence to explain the epidemiological observation that iodine insufficiency promotes the thyroid tumor development. It may also reveal some novel molecular targets for the treatment of thyroid cancer. / Thyroid cancer is the most common endocrine malignancy and exhibits the full range of malignant behaviors from the relatively indolent occult differentiated thyroid cancer to uniformly aggressive and lethal anaplastic thyroid cancer. Iodine is a well known key element in thyroid normal function maintenance and thyroid cancer development. However, the mechanisms of iodine in thyroid cancer cells development are limited. Recent researches have indicated that iodine could induce cancer cells apoptosis, staying clear from the dysfunction of iodide-specific transportation systems in thyroid cancer cells. Thus, iodine-induced apoptosis may be an effective pathway for iodine to affect thyroid cancer development, but we know little about them. / To further explore iodine on the apoptotic effects of chemotherapeutic agents in thyroid cancer, anaplastic thyroid cancer cell line ARO was used. Anaplastic thyroid cancer is lethal because of its rapid progression and poor response to chemotherapy and radioiodine therapy. The study examined the effect of moderate dose of iodine (50 muM) on the apoptosis of ARO cells treated with doxorubicin (Dox) and histone deacetylase inhibitor sodium butyrate (NaB). The cytotoxic effect of either Dox or NaB alone was limited, but co-administration of NaB and Dox (NaB-Dox) significantly increased mitochondrial-mediated apoptosis. The effects of iodine to apoptosis-induced by the two agents were diversified. Iodine reduced the apoptosis induced by Dox or NaB-Dox but promoted apoptosis induced by NaB. To explain this diversifying finding, the experiment found that iodine exaggerated NaB-mediated Bcl-xL down-regulation. In contrast, it reduced the effect of Dox on the decrease of Bcl-xL expression. Further experiments showed that iodine regulated the level of Bcl-xL in ERK- or/and p38-related pathways. The balance between ERK and p38 may determine the iodine-modulated Bcl-xL expression. The high ERK/p38 activity ratio up-regulated Bc1-xL and enabled the tumor cells to resist chemotherapy, whereas the low ERK/p38 down-regulated Bc1-xL and sensitized the tumor cells to chemotherapy. Taken together, iodine plays a critical role in apoptosis of thyroid cancer cells induced by chemotherapeutic agents. The balance between ERK and p38 may determine cell survival and death through modulating Bcl-xL expression in thyroid cancer cells. The findings provide some new insights into the roles of iodine in chemotherapeutic agents-induced apoptosis in thyroid cancer cells. / To summarize, iodine-induced apoptotic effects on thyroid cancer cells is a key pathway for iodine to influence thyroid cancer development and chemotherapy. Meanwhile MAPKs-related mutant p53, p21 and Bcl-xL expression are critical in deciding thyroid cancer cells survival and death. Moreover, iodine can influence chemotherapeutic agents-induced apoptosis through ERK/p38-mediated Bcl-xL expression. / Liu, Xiaohong. / "December 2009." / Adviser: Charles Andrew van Hasselt. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 111-146). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

129I is of major concern because of its biophilic nature, excessive inventory, long half-life (~16 million yrs), and high mobility in the natural environment that depends on its chemical speciation. Iodide (I-) has the highest mobility than iodate (IO3-) and is the predominant species in the terrestrial environment due to prevailing pH and Eh conditions. In order to transform I- to less mobile organo-iodine (OI), strong oxidants are necessary to activate the first electron transfer step from I- to reactive intermediates. The aim of this study was to determine the influence of naturally occurring aerobic bacteria isolated from an 129I contaminated aquifer (F-area of the Savannah River Site, SC) on I- oxidation and OI formation. It was demonstrated that 3 of 136 strains accumulated I- (0.2~2%) in the presence of H2O2, when incubated in the presence of an environmentally relevant concentration of I- (0.1 microM). The accumulation was likely through electrophilic substitution resulting in the iodination of cellular constituents. The results indicated that culturable I--accumulating bacteria are not directly responsible for the high fraction of oxidized iodine species (IO3- and OI, >50% of total I) present in the SRS F-area. Several bacterial strains were found to be capable of stimulating I- oxidation through excretion of oxidants and enzymes. Organic acids in spent liquid medium from 27 of 84 aerobic bacterial cultures enhanced H2O2-dependent I- oxidation 2-10 fold. Organic acids enhanced I- oxidation by (1) lowering the pH of the spent medium and (2) reacting with H2O2 to form peroxy carboxylic acids, which are strong oxidizing agents. In the absence of H2O2, spent medium from 44 of 84 bacteria cultures showed I- oxidizing capacities. One I- oxidizing bacterium was studied to characterize its extracellular I- oxidizing component(s). The I- oxidizing capability from the spent medium was inactive by treatments with heat and H2O2 and absent under anaerobic conditions. Conversely, NADH, NADPH and FMN additions stimulated I- oxidation in the spend medium. These results indicate an oxidase(s) catalyzed I- oxidation. Understanding the bacterial activities involved with I- oxidation and OI formation is expected to help reduce 129I mobility in water-soil systems.

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The main goal of my graduation thesis was to review the amount of iodine in raw milk and to consider how does the milk processing influence the changes of iodine{\crq}s content in the milk. This graduation thesis brings current information about the iodine{\crq}s content in raw milk in Czech Republic before its distribution to the market. The samples were extracted in the technology output line in the dairy works during two following years (2005 and 2006). On the whole there were taken 174 samples in which the content of iodine was set by Sandell - Kollthofa method. The average value of iodine in the market milk with 1,55% fat in the year 2005 was 534,9 {$\mu$}g . l-1 and in the year 2006 was 682,0 {$\mu$}g . l-1.

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Iodine-129 is a naturally and anthropogenically produced radioisotope (half-life: 15.7 million years) the majority of which is produced by nuclear fuel reprocessing. These releases have dispersed 129I throughout the environment making it possible to use 129I as a tracer. It is also of concern for the disposal of radioactive waste. This research develops a new laboratory method for 129I extraction and analysis, and explores the geochemical cycling and environmental fate of 129I in remote catchments following the Fukushima-Daiichi Nuclear Accident (FDNA). A new technique was developed to investigate 129I partitioning and quantitatively extract it from solid samples. Samples are combusted and volatilized iodine is trapped in solution. The efficiency is traced using the iodine isotope, 125I. This technique was proven using standard reference materials and is used in other chapters of this thesis. A baseline study of 129I in Yukon watersheds was undertaken to determine the impact of anthropogenic 129I emissions and identify possible sources. Using atmospheric back-trajectory modeling, sources of 129I from Fukushima, nuclear fuel reprocessing and marine volatilization were identified in remote watersheds. Peat moss samples showed significant retention of 129I in modern samples. Following the reconnaissance study, a catchment scale investigation of anthropogenic 129I cycling was undertaken through precipitation and runoff monitoring. 129I was found to be an excellent indicator of initial snowmelt contributions to discharge due to enrichment by dry deposition. Furthermore, water source transitions in discharge were recorded by 129I, 127I and the 129I/127I ratio showing iodine can be used as a tracer of hydrologic processes. A mass balance found that 77% of the 129I mass input accumulates annually, primarily in organic soils. Sampling of Vancouver, B.C. precipitation and groundwater was done following the FDNA to determine the fate of 129I and evaluate it as a tracer of groundwater recharge. Immediately following the FDNA the 129I concentration in precipitation increased 6 times above background. Groundwater samples also showed 129I increases consistent with expected recharge times indicating FDNA derived 129I was transported into groundwater with minimal retardation, likely via preferential flowpaths.

Iodine is an essential nutrient for humans, which is often not ingested through food in adequate quantities. Currently, Germany is once again one of the countries in which there is an iodine deficiency in the population. Women between the ages of 20 and 40 are particularly affected, a critical situation since pregnant and lactating women have an increased iodine requirement. Iodization of table salt is a widely used prophylactic measure. However, this method is not sufficient and may become less important in the future if further dietary salt reduction occurs, as nutritionists are demanding. Alternative approaches are therefore needed to improve the supply. One of these approaches is the agronomic biofortification of food crops. In this process, iodine is applied via fertilization measures during the cultivation of the plants. This gives the plants the ability to take up the mineral, which is only available in the soil to a very limited extent. In recent years, many studies have been published on the biofortification of vegetables and cereals. Foliar fertilization measures have proven to be significantly more efficient than soil fertilization measures. Nevertheless, up to now few results are available on the biofortification of fruit crops. However, fruit is also important for a healthy diet and the iodine supply of humans can only be improved if as many iodine-rich foods as possible are available. Therefore, the aim of this work was to investigate iodine biofortification of berry and tree fruit species in more detail. In order to be able to achieve this objective, trials were performed over several years with strawberries, apple and pear trees. In addition to suitable application methods, the aim was to determine the iodine form (iodide and iodate) and the necessary iodine quantity. On the one hand, the measured iodine contents in the fruit and leaf tissue allowed conclusions to be drawn about the translocation of iodine in the plant. On the other hand, this made it possible to evaluate the basic suitability for iodine biofortification of the fruit crops investigated. Since iodine has a phytotoxic effect above a certain amount, the plant compatibility should also be tested. In addition, common household processing methods, such as washing or peeling the fruit, as well as fruit storage over several months, should provide information on the extent to which such measures could reduce the iodine content. Another study parameter was the soluble solids content, as there is evidence that iodine can affect the sugar content of fruit. Furthermore, a combined application of potassium nitrate and selenium was carried out and their influence on iodine and sugar content was investigated. Selenium is also an essential trace element, which is usually inadequately absorbed through the diet. The results of the investigations showed that it was possible, in principle, to raise the iodine content of strawberries, apples and pears to a level of 50 to 100 µg iodine per 100 g fresh mass. In the case of strawberries, however, this was only feasible if the plants were in their first year of cultivation and the iodine was applied by foliar fertilization shortly before harvest. In the 2nd and 3rd year of cultivation, the plants had a very dense canopy, which prevented direct wetting of the fruit. However, direct wetting of the fruit surface with the iodine solution is imperative, as this was the only way to achieve a reliably high iodine content in the fruit mass. Soil fertilization proved to be completely unsuitable in trials with strawberries and apple trees. The translocation of iodine after soil fertilization occurred mainly via the xylem transport into the strongly transpiring leaves and not into the fruits. In addition, compared to a foliar application, a significantly higher iodine application rate was required. Furthermore, experiments with apple trees cultivated in a plastic tunnel, protected from precipitation, showed that the iodine transfer via the phloem into the fruits was only marginal. With regard to the phytotoxic effect of iodine application, no consistent difference was observed between potassium iodide and potassium iodate. Both forms of iodine did not affect yield or average individual fruit weight. Damage to fruit was not observed in any variant. However, with increasing iodine levels, significant damage to leaves was noticeable. Apple and pear trees also showed early leaf fall. Iodide generally led to significantly higher iodine contents in the plant mass after foliar application, but this was also associated with high fluctuations. With iodate, it was possible to reliably achieve the targeted iodine content in the fruit mass of apple and pear trees with an application rate of 1.5 kg iodine per hectare and meter canopy height. Washing the fruit reduced the iodine content of strawberries by up to 30%. For apples and pears, this value was about 14% at harvest and about 12% after 3 months of storage. Peeled apples and pears showed a significantly reduced iodine content. 51% of the iodine in apples was bound in the fruit peel or the cuticular waxes. A reduction of 73% was determined for pears. Cold storage for 3 months resulted in a significant loss of iodine in parts of the apple peel. At this point, the release of volatile iodine compounds is probably the cause of the reduction. However, this would still have to be confirmed by further investigations. Iodine application had a negative effect on the soluble solids content of strawberries above a certain level. It was not possible to observe significant changes for pome fruit in the trials conducted. However, the application of potassium nitrate (alone and in combination with iodine) resulted in an increase. Iodine uptake remained unaffected by the combined application of potassium nitrate and selenium. However, it was shown that selenium has a comparable uptake and translocation pattern to iodine and that a combined biofortification with both minerals is, in principle, possible. Accordingly, apple and pear trees are well suited for biofortification with iodine by foliar fertilization. However, further trials in commercial orchards are necessary to implement this process. In the future, appropriately fortified fruit could make an important contribution to the alimentary iodine supply for humans.