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

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

Ectopic A-lattice seams destabilize microtubules

Natural microtubules typically include one A-lattice seam within an otherwise helically symmetric B-lattice tube. It is currently unclear how A-lattice seams influence microtubule dynamic instability. Here we find that including extra A-lattice seams in GMPCPP microtubules, structural analogues of the GTP caps of dynamic microtubules, destabilizes them, enhancing their median shrinkage rate by >20-fold. Dynamic microtubules nucleated by seeds containing extra A-lattice seams have growth rates similar to microtubules nucleated by B-lattice seeds, yet have increased catastrophe frequencies at both ends. Furthermore, binding B-lattice GDP microtubules to a rigor kinesin surface stabilizes them against shrinkage, whereas microtubules with extra A-lattice seams are stabilized only slightly. Our data suggest that introducing extra A-lattice seams into dynamic microtubules destabilizes them by destabilizing their GTP caps. On this basis, we propose that the single A-lattice seam of natural B-lattice MTs may act as a trigger point, and potentially a regulation point, for catastrophe

Histological evidence for a supraspinous ligament in sauropod dinosaurs

Supraspinous ossified rods have been reported in the sacra of some derived sauropod dinosaurs. Although different hypotheses have been proposed to explain the origin ofthis structure, histological evidence has never been provided to support or reject any of them. In order to establish its origin, we analyse and characterize the microstructure of thesupraspinous rod of two sauropod dinosaurs from the Upper Cretaceous of Argentina. The supraspinous ossified rod is almost entirely formed by dense Haversian bone. Remains ofprimary bone consist entirely of an avascular tissue composed of two types of fibre-like structures, which are coarse and longitudinally (parallel to the main axis of the element) oriented. These structures are differentiated on the basis of their optical properties under polarized light. Very thin fibrous strands are also observed in some regions. These small fibres are all oriented parallel to one another but perpendicular to the element main axis. Histological features of the primary bone tissue indicate that the sacral supraspinous rod corresponds to an ossified supraspinous ligament. The formation of this structure appears to have been a non-pathological metaplastic ossification, possibly induced by the continuous tensile forces applied to the element.Fil: Cerda, Ignacio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Universidad Nacional de Río Negro; ArgentinaFil: Casal, Gabriel. Universidad Nacional de la Patagonia; ArgentinaFil: Martínez, Rubén Darío. Universidad Nacional de la Patagonia ; ArgentinaFil: Ibiricu, Lucio Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Male reproductive health and environmental xenoestrogens

EHP is a publication of the U.S. government. Publication of EHP lies in the public domain and is therefore without copyright. Research articles from EHP may be used freely; however, articles from the News section of EHP may contain photographs or figures copyrighted by other commercial organizations and individuals that may not be used without obtaining prior approval from both the EHP editors and the holder of the copyright. Use of any materials published in EHP should be acknowledged (for example, "Reproduced with permission from Environmental Health Perspectives") and a reference provided for the article from which the material was reproduced.Male reproductive health has deteriorated in many countries during the last few decades. In the 1990s, declining semen quality has been reported from Belgium, Denmark, France, and Great Britain. The incidence of testicular cancer has increased during the same time incidences of hypospadias and cryptorchidism also appear to be increasing. Similar reproductive problems occur in many wildlife species. There are marked geographic differences in the prevalence of male reproductive disorders. While the reasons for these differences are currently unknown, both clinical and laboratory research suggest that the adverse changes may be inter-related and have a common origin in fetal life or childhood. Exposure of the male fetus to supranormal levels of estrogens, such as diethlylstilbestrol, can result in the above-mentioned reproductive defects. The growing number of reports demonstrating that common environmental contaminants and natural factors possess estrogenic activity presents the working hypothesis that the adverse trends in male reproductive health may be, at least in part, associated with exposure to estrogenic or other hormonally active (e.g., antiandrogenic) environmental chemicals during fetal and childhood development. An extensive research program is needed to understand the extent of the problem, its underlying etiology, and the development of a strategy for prevention and intervention.Supported by EU Contract BMH4-CT96-0314

AB-QTL analysis in winter wheat: II. Genetic analysis of seedling and field resistance against leaf rust in a wheat advanced backcross population

The present study aimed to localize exotic quantitative trait locus (QTL) alleles for the improvement of leaf rust (P.triticina) resistance in an advanced backcross (AB) population, B22, which is derived from a cross between the winter wheat cultivar Batis (Triticumaestivum) and the synthetic wheat accession Syn022L. The latter was developed from hybridization of T.turgidum ssp. dicoccoides and T.tauschii. Altogether, 250 BC2F3 lines of B22 were assessed for seedling resistance against the leaf rust isolate 77WxR under controlled conditions. In addition, field resistance against leaf rust was evaluated by assessing symptom severity under natural infestation across multiple environments. Simultaneously, population B22 was genotyped with a total of 97 SSR markers, distributed over the wheat A, B and D genomes. The phenotype and genotype data were subjected to QTL analysis by applying a 3-factorial mixed model analysis of variance including the marker genotype as a fixed effect and the environments, the lines and the marker by environment interactions as random effects. The QTL analysis revealed six putative QTLs for seedling resistance and seven for field resistance. For seedling resistance, the effects of exotic QTL alleles improved resistance at all detected loci. The maximum decrease of disease symptoms (−46.3%) was associated with marker locus Xbarc149 on chromosome 1D. For field resistance, two loci had stable main effects across environments and five loci exhibited marker by environment interaction effects. The strongest effects were detected at marker locus Xbarc149 on chromosome 1D, at which the exotic allele decreased seedling symptoms by 46.3% and field symptoms by 43.6%, respectively. Some of the detected QTLs co-localized with known resistance genes, while others appear to be as novel resistance loci. Our findings indicate, that the exotic wheat accession Syn022L may be useful for the improvement of leaf rust resistance in cultivated wheat

Wheat rusts never sleep but neither do sequencers: will pathogenomics transform the way plant diseases are managed?

Field pathogenomics adds highly informative data to surveillance surveys by enabling rapid evaluation of pathogen variability, population structure and host genotype