Identification of markers linked with stem rust resistance genes Sr33 and Sr45

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Durable rust resistance in wheat is effective against multiple pathogens

Tese de doutoramento em Ciências da Saúde, no ramo de Medicina Dentária, apresentada à Faculdade de Medicina da Universidade de CoimbraA osteonecrose maxilar associada aos bifosfonatos, que se apresenta como uma lesão pós-cirúrgica associada a incapacidade de cicatrização, é um dos efeitos secundários mais frequentemente observados nos doentes submetidos a terapêutica com bifosfonatos nitrogenados. Assim, esta patologia é diagnosticada maioritariamente em doentes com metastização óssea, sob terapêutica com bifosfonatos nitrogenados intra-venosos. A fisiopatologia da osteonecrose maxilar associada aos bifosfonatos tem sido relacionada com a supressão da remodelação óssea, com a infeção local e com a toxicidade dos bifosfonatos nos tecidos envolventes, que mantém e perpetua a exposição óssea. Os fatores de risco da osteonecrose maxilar associada aos bifosfonatos foram categorizados em fatores relacionados com a terapêutica, que incluem a administração intravenosa em doenças oncológicas e a utilização do bifosfonato mais potente, o zoledronato; e factores locais, que incluem as exodontias, a colocação de implantes, a cirurgia periapical e a cirurgia periodontal que envolva os tecidos ósseos. No entanto, no caso da cirurgia periapical, não foram encontrados estudos que relacionem este procedimento com a osteonecrose maxilar. No contexto da toxicidade do zoledronato, uma vez que os compostos de fosfato de cálcio têm a capacidade de o adsorver, nomeadamente quando utilizados como sistemas transportadores de bifosfonatos, e são passíveis de aplicação nas locas cirúrgicas, constituindo substitutos ósseos adequados, colocou-se a hipótese de estes compostos poderem, potencialmente, ter um efeito protetor nos tecidos que envolvem as locas cirúrgicas. Assim, constituíram objetivos deste trabalho a avaliação da cirurgia periapical como desencadeadora de osteonecrose maxilar na presença de zoledronato e, paralelamente, a avaliação do potencial protetor da aplicação de compostos de fosfato de cálcio na loca cirúrgica. Para cumprir os objetivos propostos neste trabalho, realizaram-se estudos de química, estudos in vitro e estudos in vivo. No que respeita aos estudos de química, avaliou-se a reação entre o zoledronato e os compostos de fosfato de cálcio. Através de espetroscopia do visível e de análise elementar, verificou-se que o zoledronato é adsorvido, em solução aquosa, pelos compostos bifásicos de fosfato de cálcio. A etiologia da osteonecrose maxilar descreve um efeito deletério dos bifosfonatos nos tecidos moles, especialmente nos fibroblastos, que apresentam uma função insubstituível na cicatrização das lesões cirúrgicas orais. No contexto dos estudos in vitro, estabeleceram-se culturas primárias de fibroblastos gengivais humanos, que constituíram um modelo para avaliar a citotoxicidade na presença de zoledronato e na presença da associação zoledronato/compostos bifásicos de fosfato de cálcio. Avaliou-se a atividade metabólica dos fibroblastos gengivais humanos através do ensaio de MTT (brometo de 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazol), a sua viabilidade através do ensaio de SRB (ensaio da sulforrodamina B), os tipos de morte e o ciclo celular dos fibroblastos gengivais humanos através de citometria de fluxo e a capacidade de migração através do scratch assay. Verificou-se que o zoledronato apresentou um efeito citotóxico significativo nos fibroblastos gengivais humanos, com diminuição da atividade metabólica e da viabilidade, com aumento das populações celulares em morte por apoptose e por necrose e pela diminuição da capacidade de migração. Com a associação zoledronato/compostos bifásicos de fosfato de cálcio, foi possível diminuir, ou mesmo anular, a toxicidade do zoledronato, que se manifestou pela ausência de diferenças em relação aos grupos controlo. Nos estudos in vivo, foi utilizado um modelo experimental reprodutível já estudado, que relaciona diretamente a administração crónica de bifosfonatos com o desenvolvimento de osteonecrose maxilar após exodontia. Este modelo animal serviu como base ao desenvolvimento de um modelo de cirurgia apical com administração crónica de bifosfonatos. Os grupos de animais tratados foram submetidos a administração intra-peritoneal de zoledronato nas quatro semanas antecedentes à intervenção cirúrgica e nas duas ou três semanas seguintes. As mandíbulas foram avaliadas macroscopicamente, através da medicina nuclear, radiologia e histologia. No contexto da medicina nuclear, foi utilizado o radiofármaco 99mTc-zoledronato, que foi obtido após o desenvolvimento e a optimização de um procedimento de marcação radioquímica do zoledronato, e respetivo controlo de qualidade. Verificou-se que, nos animais submetidos à terapêutica com zoledronato, em que se desenvolveu a exodontia, existiu maior captação de 99mTc-zoledronato, menor densidade radiográfica e alterações histológicas compatíveis com cicatrização diminuída. Com a aplicação dos compostos bifásicos de fosfato de cálcio, não se observaram diferenças em relação aos animais controlo. No caso dos animais submetidos à cirurgia apical, não se verificaram alterações significativas em relação aos animais controlo, nos animais submetidos à terapêutica com zoledronato, tanto na presença como na ausência da aplicação de compostos bifásicos de fosfato de cálcio. Este trabalho de investigação permitiu elucidar acerca dos desígnios que deram origem a esta tese. No modelo animal de cirurgia periapical desenvolvido, não foi observado um atraso significativo da cicatrização nem sinais da osteonecrose maxilar, nos tempos avaliados, concluindo-se que a terapêutica com zoledronato poderá não constituir um fator de risco nesta intervenção cirúrgica. Pelo contrário, no modelo animal de exodontia confirmou-se que, efetivamente, o zoledronato constitui um fator de risco, e que os compostos bifásicos de fosfato de cálcio, apresentam potencial efeito protetor da toxicidade inerente aos bifosfonatos. Esta conclusão foi sustentada pelos estudos de química, em que se verificou a adsorção do zoledronato, corroborada por supressão da toxicidade nos estudos in vitro e cicatrização favorecida no modelo animal de exodontia com administração crónica de zoledronato.Bisphosphonate-associated osteonecrosis of the jaw, a post-surgical non-healing wound condition, is one of the most often seen side effects in patients treated with nitrogencontaining bisphosphonates. Therefore, this pathology is primarily diagnosed in patients with metastatic bone disease, receiving intravenous administration of nitrogen-containing bisphosphonates. Bisphosphonate-associated osteonecrosis of the jaw physiopathology has been related with suppression of bone turnover, local infections or soft tissue toxicity. Recent studies associate the physiopathological mechanisms of the osteonecrosis of the jaw with toxic effects of bisphosphonates on different cell types, besides osteoclast, being the most important cause of soft tissues toxicity that contributes for the maintenance of bone exposure. Bisphosphonate-associated osteonecrosis of the jaw risk factors were categorized as drug-related factors, including intravenous administration in oncological diseases and the use of the most potent bisphosphonate, zoledronate; and local factors including, dental extractions, dental implant placement, periapical surgery and periodontal surgery involving osseous injury. However, there are no studies that relate periapical surgery with osteonecrosis of the jaw. Considering zoledronate toxicity, since calcium phosphate compounds are able to adsorb it, namely when used as drug delivery vehicle, and are also used in surgical wounds, as a bone substitute, it was hypothesised this compounds had a potential protective effect to the soft tissues surrounding surgical osseous wounds. Thus, the aim of this study was to assess periapical surgery as a trigger of osteonecrosis of the jaw in the presence of zoledronate and also the potential protective effect of calcium phosphate compounds when applied in the surgical wound. To fulfil the proposed objectives of this work were carried out studies of chemistry, in vitro and in vivo studies. Regarding chemical studies, it was evaluated the chemical reaction between zoledronate and calcium phosphate compounds. Through ultraviolet-visible spectroscopy and elemental analysis it has been found that zoledronate, in aqueous solution, was adsorbed by biphasic calcium phosphate compounds. Bisphosphonate-associated osteonecrosis of the jaw aetiology describes a deleterious effect of bisphosphonates on soft tissues, especially on fibroblasts, which play an important role in oral wound healing. Considering in vitro studies it was established a primary culture of human gingival fibroblasts that constituted a model to evaluate the cytotoxicity in the presence of zoledronate and of zoledronate/biphasic calcium phosphate compounds association. It was investigated the metabolic activity of human gingival fibroblasts through MTT (3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, cell viability through SRB (sulforhodamine B) assay, types of cell death and cell cycle through flow cytometry and migration ability of human gingival fibroblasts through scratch assay. It was verified that zoledronate had a strong cytotoxic effect in the human gingival fibroblasts, by the reduction of metabolic activity, cell viability, increase of cells in apoptosis and reduction of migration. With the association zoledronate/biphasic calcium phosphate compounds it was possible to reduce or abolish zoledronate toxicity, as it was demonstrated by the absence of differences related to control. In the in vivo study it was used a reproducible experimental model that directly relates chronic bisphosphonate administration with the development of osteonecrosis of the jaw with tooth extraction. This animal model also served as basis to the development of a osteotomy in periapical surgery model with chronic bisphosphonate administration. The animals were treated with zoledronate intraperitoneally, during the four weeks that preceded the surgeries and in the following two and three weeks. The mandibles were macroscopic evaluated, examined by nuclear medicine, radiology and histologically analysed. Concerning nuclear medicine it was used the radiopharmaceutical 99mTc-zoledronate, which was obtained after the development and optimization of a procedure for zoledronate radiochemical labelling, and respective quality control. It has been found that the animals with zoledronate, submitted to tooth extraction, had a higher 99mTc-zoledronate uptake, lower radiological density and histologic images compatible with a decreased healing. With biphasic calcium phosphate compounds application, there were no differences related to controls. In the animals submitted to osteotomy in periapical surgery there were no significant differences related to the controls, in both animals with zoledronate, with and without biphasic calcium phosphate compounds application. This research work allowed the clarification of the goals that led to this thesis. In the created animal model of osteotomy in periapical surgery, it was not observed a significant delay in the wound healing, neither osteonecrosis of the jaw, in the evaluated periods, therefore it was conclude that zoledronate therapeutic may not constitute a risk factor in this surgical approach. Contrarily, in the tooth extraction animal model, it was confirmed that zoledronate therapeutic constitute a risk factor, and it was found that biphasic calcium phosphate compounds presents a potential protector effect from bisphosphonates toxicity. This conclusion was supported by the chemical studies, in which it was observed adsorption of zoledronate, corroborated by the lower toxicity in the in vitro studies and by the improved cicatrisation in the tooth extraction animal model with chronic bisphosphonates administration

Wyalkatchem reselections differentiate the adult plant resistance gene Yr29 in an Australian wheat background

Contains fulltext : 131342.pdf (publisher's version ) (Open Access)COGSCI, 23 juli 201

The inhibitor of Pm8 in certain 1BL.1RS wheat genotypes

INTRODUCTION: Nevirapine (NVP) induces cytochrome P450 3A4 by which rilpivirine (RPV) is metabolized. Switching NVP to RPV could result in decreased RPV exposure with subsequent virological failure and dyslipidemia because NVP is regarded as the least dyslipidemic, non-nucleoside, reverse transcriptase inhibitor. This trial evaluated the efficacy, pharmacokinetics, safety and cardiovascular risks of switching NVP to RPV. MATERIALS AND METHODS: Prospective open label controlled trial. HIV-1 patients with HIV-1 RNA <50 copies/mL on once daily NVP, emtricitabine/tenofovir (FTC/TDF) switched to single tablet RPV/FTC/TDF. Eligible patients on NVP, FTC/TDF were controls. Primary endpoint was week 12 HIV-1 RNA <50 copies/mL by intention to treat analysis. Secondary endpoints were week 24 HIV-1 RNA <50 copies/mL, NVP and RPV pharmacokinetics, safety and fasting lipids, Framingham risk scores (FRS) and Adult Treatment Panel III (ATP-III) lipid goals. RESULTS: Of 189 eligible patients, we included 50 RPV switchers and 139 NVP controls. Week 12 HIV-RNA was <50 copies/mL in 46/50 switchers (92.0%) which was not different from the hypothesized 90% week 12 suppression rate (p=.431). Forty-four of 50 switchers had week 24 HIV-1 RNA <50 copies/mL compared to 126/139 controls (difference: 2.6%, 95% CI -7.6% to 12.8%, p=.593). NVP plasma concentrations were below detection level in all at week 3. Mean week 1 RPV trough concentration was 0.083 mg/L and comparable to phase III trial data (p=0.747). Adverse events occurred in 36 switchers, the majority (82.0%) were grade one. Two switchers discontinued RPV for side effects. Significant changes over 24 weeks (p<0.001) were observed in switchers on total cholesterol (TC, -0.67 mmol/L, 95% CI -0.50 to 0.83), low density lipoprotein (LDL)-C (-0.36, 95% CI -0.21 to -0.51) and high density lipoprotein (HDL)-C (-0.28, 95% CI -0.20 to -0.35). The TC/HDL-C ratio increased 0.20 (95% CI 0.02 to 0.37; p=.029) and systolic blood pressure decreased 6.0 mmHg (95% CI -1.7 to -10.3; p=.007). The median FRS did not change over 24 weeks (8.4% vs. 7.7%; p=.119). More patients achieved LDL-C (+15%; p=.016) and TC (+25%; p<0.001) ATP-III treatment goals at week 24 on RPV. CONCLUSIONS: A NVP to RPV switch does not influence RPV exposure and results in adequate ongoing HIV-1 suppression. RPV could be an option for patients at risk for cardiovascular diseases