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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Applications d'une modulation pharmacologique des dérives des formes réactives de l'oxygène pour une optimisation thérapeutique des patients traités par chimiothérapie / Applications of derivatives of pharmacological modulation of reactive oxygen species form for optimization of patients treated with chemotherapy

Coriat, Romain 16 November 2012 (has links)
Les formes réactives de l’oxygène (FRO) ont un rôle bien établi dans l’oncogénèse et le fonctionnement des cellules tumorales en augmentant les capacités de prolifération et d’invasion cellulaire. Les FRO présentent une moindre toxicité dans les cellules normales où le niveau de stress oxydant est bas et les systèmes d’oxydoréduction opérationnels. Une modulation pharmacologique de l’équilibre d’oxydoréduction permet d’améliorer l’efficacité des molécules cytotoxiques qui agissent sur les FRO. L’activité anti tumorale de la chimiothérapie étant médiée en partie par le stress oxydant, nous nous sommes dans un premier temps intéressé aux variations du stress oxydant lors d’un traitement par le sorafenib (Nexavar©), un inhibiteur de tyrosine kinases. Nous avons mis en évidence une activité anti tumorale du sorafenib liée à l’augmentation de la production d’anion superoxyde par les cellules. Ce phénomène nous a permis d’identifier un marqueur prédictif d’efficacité du sorafenib, le dosage des Produits d’Oxydation Avancée des Protéines (AOPP), dans le sérum des patients cirrhotiques développant un carcinome hépatocellulaire. Sachant que l’efficacité anti tumorale des chimiothérapies conventionnelles passe en partie par l’induction de FRO, nous nous sommes intéressés dans un deuxième temps au mangafodipir, un modulateur du stress oxydant, qui est connu pour augmenter l’index thérapeutique des agents cytotoxiques in vivo. Le mangafodipir diminue les effets toxiques du stress oxydatif dans des cellules non tumorales et potentialise l’activité anti tumorale de l’oxaliplatine. Ces données nous ont conduits à explorer in vivo et in vitro le mécanisme de la neurotoxicité induite par l’oxaliplatine et le rôle protecteur du mangafodipir. Nous avons ainsi observé dans un modèle murin que le mangafodipir prévient la neurotoxicité induite par l’oxaliplatine au niveau de la gaine de myéline. Nous avons confirmé ces résultats chez l’homme lors d’une étude de phase II. Compte tenu des taux plus élevés de FRO dans les cellules tumorales par rapport aux cellules normales, plusieurs stratégies ont été proposées pour cibler sélectivement les tumeurs sans endommager les tissus sains avec des modulateurs du stress oxydant. Notre troisième axe de travail a eu pour objectif d’identifier et de valider de nouvelles molécules liées à la modulation des FRO. Cette étude a été réalisée dans le cadre d’un projet du programme Européen Pierre et Marie Curie (International Training Network 7-FP7-2007-1-1-ITN201114), au sein du réseau REDCAT. Cette collaboration a permis de concevoir et de synthétiser de nouveaux agents thérapeutiques, les organochalcogenes. Nous avons mis en évidence in vitro et in vivo le potentiel anti tumoral de cette nouvelle classe thérapeutique et principalement celui du composé LAB027. Le LAB027 présente une activité anti tumorale seul ou associé à l’oxaliplatine. L’ensemble de ces travaux nous a permis d’envisager l’évaluation précoce de l’efficacité du sorafenib par un marqueur du stress oxydant, les AOPP, de mettre en évidence l’effet anti-neurotoxique d’un mimétique de la superoxyde dismutase, le mangafodipir et d’identifier une nouvelle classe médicamenteuse en oncologie, les organochalcogènes. Ces optimisations thérapeutiques permettent d’envisager une meilleure prise en charge des malades traités par chimiothérapie afin d’optimiser l’efficacité des traitements utilisés en oncologie. / Reactive oxygen species (ROS) forms have an established role in oncogenesis and tumor cell function by increasing the capacity of proliferation and cell invasion. ROS have a lower toxicity in normal cells where the level of oxidative stress is low and redox systems operational. Pharmacological modulation of redox balance enhances the effectiveness of cytotoxic molecules that act on the FRO. The anti-tumor activity of chemotherapy is mediated in part by oxidative stress, we initially interested in the changes of oxidative stress during treatment with sorafenib (Nexavar©), an inhibitor of tyrosine kinases. We have demonstrated anti-tumor activity of sorafenib due to increased production of superoxide anion by cells. This allowed us to identify a predictive marker of efficacy of sorafenib dosing Products Advanced Oxidation Protein (AOPP) in the serum of patients with cirrhosis develop hepatocellular carcinoma. Knowing that the antitumor efficacy of conventional chemotherapy is partly through the induction of ROS, we are interested in a second time mangafodipir, a modulator of oxidative stress, which is known to increase the therapeutic index of cytotoxic agents in vivo. Mangafodipir reduces the toxic effects of oxidative stress in non-tumor cells and potentiates the anti-tumor activity of oxaliplatin. These data led us to explore in vivo and in vitro the mechanism of neurotoxicity induced by oxaliplatin and the protective role of mangafodipir. We observed in a mouse model that mangafodipir prevents neurotoxicity induced by oxaliplatin in the myelin sheath. We confirmed these results in humans in a phase II study. Given the higher levels of ROS in tumor cells compared to normal cells, several strategies have been proposed to selectively target tumors without damaging healthy tissue with modulators of oxidative stress. Our third area of work has aimed to identify and validate novel molecules related to the modulation of ROS. This study was conducted as part of a project of the European Pierre et Marie Curie (International Training Network 7-FP7-2007-1-1-ITN201114) within the network REDCAT. This collaboration has led to the design and synthesis of new therapeutic agents, organochalcogenes. We have demonstrated in vitro and in vivo antitumor potential of this new therapeutic class and mainly composed of the LAB027. LAB027 the present anti-tumor activity alone or in combination with oxaliplatin. All of this work has allowed us to consider the early assessment of the effectiveness of sorafenib a marker of oxidative stress, the AOPP, highlight the anti-nerve of a superoxide dismutase mimetic, mangafodipir and identify a new class of drugs in oncology, organochalcogènes. These optimizations allow therapeutic consider better care of patients treated with chemotherapy to enhance the efficacy of treatments used in oncology.
2

AVALIAÇÃO DO ESTRESSE OXIDATIVO ATRAVÉS DA DETERMINAÇÃO DE PRODUTOS DA OXIDAÇÃO AVANÇADA DE PROTEÍNAS (AOPP) EM PACIENTES COM ANEMIA MICROCÍTICA E HIPOCRÔMICA / EVALUATION OF OXIDATIVE STRESS BY DETERMINATION OF ADVANCED OXIDATION PROTEIN PRODUCTS (AOPP) IN PATIENTS WITH ANEMIA MICROCYTIC AND HYPOCROMIC

Danieli, Karina 31 August 2011 (has links)
The etiology of anemia is characterized by abnormal hemoglobin synthesis. Iron deficiency is characterized by microcytic and hipochromic red cells and low serum ferritin, being the most prevalent nutritional deficiency worldwide, responsible for iron deficiency anemia (FA). Anemia of chronic disease (ACD) is considered a clinical syndrome associated with chronic inflammation, infectious disease, neoplastic or traumatic, being the second most frequent cause of anemia. The severity of anemia correlates with the degree of pathology. Both have functional iron deficiency. The objective of this study was to evaluate hematological and inflammatory, as well as the presence of oxidative stress in patients with anemia. The blood analyzer was done by the CBC, automated hematology analyzer processed, Sysmex® (Automated Hematology Analyzer). The quantitative determination of ferritin is serum was done in IMMULITE analyzer. Levels of CRP and AOPP were performed in serum by automated Cobas MIRA® (Roche Diagnostics). Statistical analysis was performed using GraphPad Prism 5. We analyzed 70 patients with microcytic and hypochromic anemia. Of these, 29 (41.43%) were diagnosed as iron deficiency anemia and 41 (58.57%) with anemia of chronic disease. As a control group, we used samples from 44 patients with hematological parameters, serum ferritin, CRP and AOPP normal. The values of MCV, MCH and MCHC significantly lower in iron deficiency anemia. Ferritin levels showed that it can be considered both a measure of iron store as an inflammatory marker. In ACD there is increased production of inflammatory cytokines, which, in turn, increases the concentration of C-reactive protein (CRP). The results indicate that AOPP in both groups with anemia showed increased levels of this marker, which indicates the presence of oxidative stress, probably caused by increased production of free radicals and decreases in enzyme activities of the antioxidant defense system of erythrocytes. / A etiologia das anemias caracteriza-se pela síntese anormal de hemoglobina. A deficiência de ferro é caracterizada por eritrócitos microcíticos e hipocrômicos e por ferritina sérica baixa, sendo a carência nutricional mais prevalente em todo o mundo, responsável pela Anemia Ferropriva (AF). A Anemia de Doença Crônica (ADC) é considerada uma síndrome clínica, associada à inflamação crônica, doença infecciosa, traumática ou neoplásica, sendo a segunda causa mais freqüente de anemia. Ambas apresentam deficiência funcional de ferro. O objetivo deste trabalho foi avaliar parâmetros hematológicos e inflamatórios, bem como a presença de estresse oxidativo em pacientes com anemia. A análise hematológica foi feita através do hemograma, processado em analisador hematológico automatizado, Sysmex® (Automated Hematology Analyzer). O doseamento quantitativo da ferritina no soro foi feito em analisador IMMULITE. A dosagem de Proteína C-Reativa (PCR) e de Produtos da Oxidação Avançada de Proteínas (AOPP) foram realizadas no soro através do sistema automatizado Cobas MIRA® (Roche Diagnostics). A análise estatística foi realizada através do programa GraphPad Prism 5. Foram analisados 70 pacientes portadores de anemia microcítica e hipocrômica. Destes, 29 (41,43%) foram diagnosticados como anemia ferropriva e 41 (58,57%) com anemia de doença crônica. Como grupo controle, foram utilizadas amostras de 44 indivíduos com parâmetros hematológicos, níveis de ferritina, PCR e AOPP dentro da normalidade. Os valores de VCM, HCM e CHCM foram significativamente menores na anemia ferropriva. Os níveis de ferritina revelaram que ela pode ser considerada tanto uma medida das reservas de ferro quanto um marcador inflamatório. Na ADC há aumento da produção de citocinas inflamatórias, que, por sua vez, aumenta também a concentração de PCR. Os resultados do AOPP indicam que ambos os grupos com anemia apresentaram níveis aumentados deste marcador, o que indica a presença de estresse oxidativo, provavelmente causado por aumento na produção de radicais livres e declínio das atividades das enzimas do sistema de defesa antioxidante dos eritrócitos.
3

Applications d'une modulation pharmacologique des dérives des formes réactives de l'oxygène pour une optimisation thérapeutique des patients traités par chimiothérapie

Coriat, Romain 16 November 2012 (has links) (PDF)
Les formes réactives de l'oxygène (FRO) ont un rôle bien établi dans l'oncogénèse et le fonctionnement des cellules tumorales en augmentant les capacités de prolifération et d'invasion cellulaire. Les FRO présentent une moindre toxicité dans les cellules normales où le niveau de stress oxydant est bas et les systèmes d'oxydoréduction opérationnels. Une modulation pharmacologique de l'équilibre d'oxydoréduction permet d'améliorer l'efficacité des molécules cytotoxiques qui agissent sur les FRO. L'activité anti tumorale de la chimiothérapie étant médiée en partie par le stress oxydant, nous nous sommes dans un premier temps intéressé aux variations du stress oxydant lors d'un traitement par le sorafenib (Nexavar©), un inhibiteur de tyrosine kinases. Nous avons mis en évidence une activité anti tumorale du sorafenib liée à l'augmentation de la production d'anion superoxyde par les cellules. Ce phénomène nous a permis d'identifier un marqueur prédictif d'efficacité du sorafenib, le dosage des Produits d'Oxydation Avancée des Protéines (AOPP), dans le sérum des patients cirrhotiques développant un carcinome hépatocellulaire. Sachant que l'efficacité anti tumorale des chimiothérapies conventionnelles passe en partie par l'induction de FRO, nous nous sommes intéressés dans un deuxième temps au mangafodipir, un modulateur du stress oxydant, qui est connu pour augmenter l'index thérapeutique des agents cytotoxiques in vivo. Le mangafodipir diminue les effets toxiques du stress oxydatif dans des cellules non tumorales et potentialise l'activité anti tumorale de l'oxaliplatine. Ces données nous ont conduits à explorer in vivo et in vitro le mécanisme de la neurotoxicité induite par l'oxaliplatine et le rôle protecteur du mangafodipir. Nous avons ainsi observé dans un modèle murin que le mangafodipir prévient la neurotoxicité induite par l'oxaliplatine au niveau de la gaine de myéline. Nous avons confirmé ces résultats chez l'homme lors d'une étude de phase II. Compte tenu des taux plus élevés de FRO dans les cellules tumorales par rapport aux cellules normales, plusieurs stratégies ont été proposées pour cibler sélectivement les tumeurs sans endommager les tissus sains avec des modulateurs du stress oxydant. Notre troisième axe de travail a eu pour objectif d'identifier et de valider de nouvelles molécules liées à la modulation des FRO. Cette étude a été réalisée dans le cadre d'un projet du programme Européen Pierre et Marie Curie (International Training Network 7-FP7-2007-1-1-ITN201114), au sein du réseau REDCAT. Cette collaboration a permis de concevoir et de synthétiser de nouveaux agents thérapeutiques, les organochalcogenes. Nous avons mis en évidence in vitro et in vivo le potentiel anti tumoral de cette nouvelle classe thérapeutique et principalement celui du composé LAB027. Le LAB027 présente une activité anti tumorale seul ou associé à l'oxaliplatine. L'ensemble de ces travaux nous a permis d'envisager l'évaluation précoce de l'efficacité du sorafenib par un marqueur du stress oxydant, les AOPP, de mettre en évidence l'effet anti-neurotoxique d'un mimétique de la superoxyde dismutase, le mangafodipir et d'identifier une nouvelle classe médicamenteuse en oncologie, les organochalcogènes. Ces optimisations thérapeutiques permettent d'envisager une meilleure prise en charge des malades traités par chimiothérapie afin d'optimiser l'efficacité des traitements utilisés en oncologie.
4

Associação entre metabolismo do ferro e estresse oxidativo em pacientes com doeça de Parkinson

Medeiros, Márcio Schneider January 2014 (has links)
Introdução: A fisiopatologia da doença de Parkinson está associada a lesões por estresse oxidativo/nitrosativo. O ferro encontra-se acumulado na substância negra (SN) de pacientes com DP e está relacionado com esse dano através das espécies reagentes de oxigênio (EROs) e de nitrogênio (ERNs) na reação de Fenton. EROs e ERNs são produzidas normalmente em processos celulares e inflamatórios, e controladas por sistemas antioxidantes. Objetivo: Avaliar níveis periféricos de ferro em pacientes com DP para determinar se acúmulo na SN está relacionado com níveis elevados no sangue. Determinar biomarcadores periféricos confiáveis de estresse oxidativo/nitrosativo Métodos: Selecionados 40 pacientes com DP e 46 indivíduos controles para comparar níveis séricos de ferro, ferritina e transferrina, e de biomarcadores de estresse oxidativo/nitrosativo: superóxido dismutase (SOD), catalase, óxido nítrico (NOx), substâncias reativas ao ácido tiobarbitúrico (TBARS), tióis não-proteicos, “advanced oxidation protein products” (AOPP), “ferric reducing ability of plasma” (FRAP), NTPDases, ecto-5’-nucleotidase, adenosina deaminase (ADA), mieloperoxidase, albumina modificada pela isquemia (IMA) e vitamina C. Resultados: Níveis de ferro estavam diminuídos em pacientes com DP, enquanto ferritina e transferrina não mostraram diferença. Os biomarcadores de estresse oxidativo como TBARS, AOPP, NTPDases, IMA, mieloperoxidase, FRAP, vitamina C e tiois não-proteicos encontraram-se significativamente aumentados na DP. SOD, catalase, ecto-5’-nucleotidase não foram diferentes entre os grupos e os marcadores NOx e ADA foram significativamente aumentados nos controles. Nenhuma correlação foi encontrada entre os biomarcadores e dados sociodemográficos e de características da doença. Conclusão: Níveis plasmáticos de ferro encontram-se diminuídos em pacientes com DP comparados com controles saudáveis. Os biomarcadores TBARS, AOPP, NTPDases, IMA e mieloperoxidase mostraram-se confiáveis para lesão oxidativa, enquanto tióis não-proteicos, FRAP e vitamina C demonstram diminuição da capacidade antioxidante na DP. / Background: Parkinson’s disease (PD) pathophysiology is associated with oxidative/nitrosative stress damage. Iron accumulates in the substantia nigra (SN) of PD patients and is related to this damage along with oxygen and nitrogen reactive species (ROS, RNS) through Fenton reaction. ROS and RNS are normally produced in cell and inflammatory processes, controlled by antioxidant systems. Objective: To determine peripheral levels of iron, ferritin and transferrin in PD patients to evaluate whether iron accumulation in the SN could be related to serum levels. To determine reliable peripheral biomarkers of oxidative/nitrative stress. Methods: Forty PD patients and 46 controls were selected to compared serum levels of iron, ferritin, transferrin and oxidative/nitrative stress biomarkers: superoxide dismutase (SOD), catalase, nitric oxide (NOx), thiobarbituric acid reactive substances (TBARS), non-protein thiols, advanced oxidation protein products (AOPP), ferric reducing ability of plasma (FRAP), NTPDases, ecto-5’-nucleotidase, adenosine deaminase (ADA), myeloperoxidase, ischemic-modified albumin (IMA) and vitamin C. Results: Iron levels were decreased in patients with PD, while ferritin and transferrin were not different. Oxidative stress biomarkers, TBARS, AOPP, NTPDases, IMA, myeloperoxidase, FRAP, vitamin C and non-proteic thiols were significantly higher in PD. SOD, catalase, ecto-5’-nucleotidase were not different between the groups and biomarkers NOx and ADA were significantly increased in the controls. No correlation was found between biomarkers and sociodemographic and disease data. Conclusion: Plasmatic levels of iron are decreased in patients with PD compared to healthy controls. Biomarkers TBARS, AOPP, NTPDases, IMA and myeloperoxidase presented as reliable to measure oxidative/nitrative damage, while non-proteic thiols, FRAP and vitamin C show a decrease in the antioxidant capacity in PD.
5

Associação entre metabolismo do ferro e estresse oxidativo em pacientes com doeça de Parkinson

Medeiros, Márcio Schneider January 2014 (has links)
Introdução: A fisiopatologia da doença de Parkinson está associada a lesões por estresse oxidativo/nitrosativo. O ferro encontra-se acumulado na substância negra (SN) de pacientes com DP e está relacionado com esse dano através das espécies reagentes de oxigênio (EROs) e de nitrogênio (ERNs) na reação de Fenton. EROs e ERNs são produzidas normalmente em processos celulares e inflamatórios, e controladas por sistemas antioxidantes. Objetivo: Avaliar níveis periféricos de ferro em pacientes com DP para determinar se acúmulo na SN está relacionado com níveis elevados no sangue. Determinar biomarcadores periféricos confiáveis de estresse oxidativo/nitrosativo Métodos: Selecionados 40 pacientes com DP e 46 indivíduos controles para comparar níveis séricos de ferro, ferritina e transferrina, e de biomarcadores de estresse oxidativo/nitrosativo: superóxido dismutase (SOD), catalase, óxido nítrico (NOx), substâncias reativas ao ácido tiobarbitúrico (TBARS), tióis não-proteicos, “advanced oxidation protein products” (AOPP), “ferric reducing ability of plasma” (FRAP), NTPDases, ecto-5’-nucleotidase, adenosina deaminase (ADA), mieloperoxidase, albumina modificada pela isquemia (IMA) e vitamina C. Resultados: Níveis de ferro estavam diminuídos em pacientes com DP, enquanto ferritina e transferrina não mostraram diferença. Os biomarcadores de estresse oxidativo como TBARS, AOPP, NTPDases, IMA, mieloperoxidase, FRAP, vitamina C e tiois não-proteicos encontraram-se significativamente aumentados na DP. SOD, catalase, ecto-5’-nucleotidase não foram diferentes entre os grupos e os marcadores NOx e ADA foram significativamente aumentados nos controles. Nenhuma correlação foi encontrada entre os biomarcadores e dados sociodemográficos e de características da doença. Conclusão: Níveis plasmáticos de ferro encontram-se diminuídos em pacientes com DP comparados com controles saudáveis. Os biomarcadores TBARS, AOPP, NTPDases, IMA e mieloperoxidase mostraram-se confiáveis para lesão oxidativa, enquanto tióis não-proteicos, FRAP e vitamina C demonstram diminuição da capacidade antioxidante na DP. / Background: Parkinson’s disease (PD) pathophysiology is associated with oxidative/nitrosative stress damage. Iron accumulates in the substantia nigra (SN) of PD patients and is related to this damage along with oxygen and nitrogen reactive species (ROS, RNS) through Fenton reaction. ROS and RNS are normally produced in cell and inflammatory processes, controlled by antioxidant systems. Objective: To determine peripheral levels of iron, ferritin and transferrin in PD patients to evaluate whether iron accumulation in the SN could be related to serum levels. To determine reliable peripheral biomarkers of oxidative/nitrative stress. Methods: Forty PD patients and 46 controls were selected to compared serum levels of iron, ferritin, transferrin and oxidative/nitrative stress biomarkers: superoxide dismutase (SOD), catalase, nitric oxide (NOx), thiobarbituric acid reactive substances (TBARS), non-protein thiols, advanced oxidation protein products (AOPP), ferric reducing ability of plasma (FRAP), NTPDases, ecto-5’-nucleotidase, adenosine deaminase (ADA), myeloperoxidase, ischemic-modified albumin (IMA) and vitamin C. Results: Iron levels were decreased in patients with PD, while ferritin and transferrin were not different. Oxidative stress biomarkers, TBARS, AOPP, NTPDases, IMA, myeloperoxidase, FRAP, vitamin C and non-proteic thiols were significantly higher in PD. SOD, catalase, ecto-5’-nucleotidase were not different between the groups and biomarkers NOx and ADA were significantly increased in the controls. No correlation was found between biomarkers and sociodemographic and disease data. Conclusion: Plasmatic levels of iron are decreased in patients with PD compared to healthy controls. Biomarkers TBARS, AOPP, NTPDases, IMA and myeloperoxidase presented as reliable to measure oxidative/nitrative damage, while non-proteic thiols, FRAP and vitamin C show a decrease in the antioxidant capacity in PD.
6

Associação entre metabolismo do ferro e estresse oxidativo em pacientes com doeça de Parkinson

Medeiros, Márcio Schneider January 2014 (has links)
Introdução: A fisiopatologia da doença de Parkinson está associada a lesões por estresse oxidativo/nitrosativo. O ferro encontra-se acumulado na substância negra (SN) de pacientes com DP e está relacionado com esse dano através das espécies reagentes de oxigênio (EROs) e de nitrogênio (ERNs) na reação de Fenton. EROs e ERNs são produzidas normalmente em processos celulares e inflamatórios, e controladas por sistemas antioxidantes. Objetivo: Avaliar níveis periféricos de ferro em pacientes com DP para determinar se acúmulo na SN está relacionado com níveis elevados no sangue. Determinar biomarcadores periféricos confiáveis de estresse oxidativo/nitrosativo Métodos: Selecionados 40 pacientes com DP e 46 indivíduos controles para comparar níveis séricos de ferro, ferritina e transferrina, e de biomarcadores de estresse oxidativo/nitrosativo: superóxido dismutase (SOD), catalase, óxido nítrico (NOx), substâncias reativas ao ácido tiobarbitúrico (TBARS), tióis não-proteicos, “advanced oxidation protein products” (AOPP), “ferric reducing ability of plasma” (FRAP), NTPDases, ecto-5’-nucleotidase, adenosina deaminase (ADA), mieloperoxidase, albumina modificada pela isquemia (IMA) e vitamina C. Resultados: Níveis de ferro estavam diminuídos em pacientes com DP, enquanto ferritina e transferrina não mostraram diferença. Os biomarcadores de estresse oxidativo como TBARS, AOPP, NTPDases, IMA, mieloperoxidase, FRAP, vitamina C e tiois não-proteicos encontraram-se significativamente aumentados na DP. SOD, catalase, ecto-5’-nucleotidase não foram diferentes entre os grupos e os marcadores NOx e ADA foram significativamente aumentados nos controles. Nenhuma correlação foi encontrada entre os biomarcadores e dados sociodemográficos e de características da doença. Conclusão: Níveis plasmáticos de ferro encontram-se diminuídos em pacientes com DP comparados com controles saudáveis. Os biomarcadores TBARS, AOPP, NTPDases, IMA e mieloperoxidase mostraram-se confiáveis para lesão oxidativa, enquanto tióis não-proteicos, FRAP e vitamina C demonstram diminuição da capacidade antioxidante na DP. / Background: Parkinson’s disease (PD) pathophysiology is associated with oxidative/nitrosative stress damage. Iron accumulates in the substantia nigra (SN) of PD patients and is related to this damage along with oxygen and nitrogen reactive species (ROS, RNS) through Fenton reaction. ROS and RNS are normally produced in cell and inflammatory processes, controlled by antioxidant systems. Objective: To determine peripheral levels of iron, ferritin and transferrin in PD patients to evaluate whether iron accumulation in the SN could be related to serum levels. To determine reliable peripheral biomarkers of oxidative/nitrative stress. Methods: Forty PD patients and 46 controls were selected to compared serum levels of iron, ferritin, transferrin and oxidative/nitrative stress biomarkers: superoxide dismutase (SOD), catalase, nitric oxide (NOx), thiobarbituric acid reactive substances (TBARS), non-protein thiols, advanced oxidation protein products (AOPP), ferric reducing ability of plasma (FRAP), NTPDases, ecto-5’-nucleotidase, adenosine deaminase (ADA), myeloperoxidase, ischemic-modified albumin (IMA) and vitamin C. Results: Iron levels were decreased in patients with PD, while ferritin and transferrin were not different. Oxidative stress biomarkers, TBARS, AOPP, NTPDases, IMA, myeloperoxidase, FRAP, vitamin C and non-proteic thiols were significantly higher in PD. SOD, catalase, ecto-5’-nucleotidase were not different between the groups and biomarkers NOx and ADA were significantly increased in the controls. No correlation was found between biomarkers and sociodemographic and disease data. Conclusion: Plasmatic levels of iron are decreased in patients with PD compared to healthy controls. Biomarkers TBARS, AOPP, NTPDases, IMA and myeloperoxidase presented as reliable to measure oxidative/nitrative damage, while non-proteic thiols, FRAP and vitamin C show a decrease in the antioxidant capacity in PD.
7

SOYBEAN PLANT POPULATIONS AND DIGITAL ASSESSMENTS

Richard M Smith (14279081), Shaun N. Casteel (10972050), Jason Ackerson (9749436), Keith Cherkauer (7890221), Melba Crawford (14279296) 20 December 2022 (has links)
<p> Soybean seed cost has dramatically increased in recent decades which has led to producer interest in lowering input cost through reductions in seeding rate. Fifty-eight seeding rate trials of soybean were conducted at field-scale in Indiana from 2010 to 2021 to update recommendations of seeding rates and plant population. The objectives were to determine the agronomic optimal seeding rate (AOSR) and plant population (AOPP) based on planting equipment, tillage practices, and planting date. Economic optimal seeding rate (EOSR) was also determined based on these field scenarios. Harvest AOPP was not influenced by planting equipment (~212,000 plants ha-1) or tillage (~239,000 plants ha-1), but AOSR varied. Soybean seeded with a row-crop planter optimized grain yield with 352,600 seeds ha-1; whereas, the grain drill required 75,200 more seeds ha-1. Soybean seeded into conventional tillage maximized grain yield at 380,400 seeds ha-1; whereas, under no-till conditions 41,400 more seeds ha-1 were required. Timely planting required 417,300 seeds ha-1 to optimize grain yield, which resulted in harvest AOPP of 216,700 plants ha-1. Conversely, late plantings required 102,800 fewer seeds ha-1 but 36,200 more plants ha-1 than timely planting. Depending on seed cost and soybean market price, seeding rates could be reduced 13,700 to 92,800 seeds ha-1 below AOSR to maximize profit.</p> <p>Secondly, digital imagery with high spatial resolution was collected with an unmanned aerial vehicle (UAV) to develop a simple and practical method to segment soybean from non-plant pixels. The best vegetation indices were selected to segment young soybean plants (VC to V6). Two field-scale trials of soybean were planted in 2020 with the agronomic trial design of two varieties x five seeding rates with three replications. The imagery was collected during this period as it coincides with the time for determining whether a soybean stand should be replanted. Five relative vegetative indices based on the red, green, and blue (RGB) imagery were evaluated: excess greenness index (ExG), excess redness index (ExR), green leaf index (GLI), normalized green-red difference index (NGRDI) and visible atmospheric resistance index (VARI). Both GLI and ExG were superior in overall accuracy compared to all other vegetative indices with very small soybean plants (VC to V1 growth stages). VARI and NGRDI had relatively poor overall accuracy at VC and V1, but had similar overall accuracy to GLI as soybean plants grew larger (V2 to V6 growth stages). Across all growth stages and locations, ExR performed the poorest. Moreover, GLI had consistent performance across the range of growth stages, suggesting its suitability for early soybean stand assessment methods.</p> <p>Six field-scale trials were established in 2020 and 2021 in Indiana with two varieties seeded from 123,000 to 618,000 seeds ha-1. Canopy cover was calculated using GLI to create binary segmentation of plant pixels and non-plant pixels. UAV-derived canopy cover measurements were correlated with plant population of soybean from VC to V4 and growing degree days (GDD) after planting. Yield potential (75, 80, 85, 90, 95, 100%) was correlated with canopy cover from VC to V4 and GDD after planting. Canopy cover of 2.1, 5.0, 8.9 and 13.8% by 150, 250, 350, and 450 GDD°C after planting, respectively, would maximize yield. Canopy cover for 75% yield potential was one-fourth as much as the 100% yield potential. Recommended threshold for replant decisions should be based on canopy cover to attain 95% yield potential. Field observations below a canopy cover of 1.8, 4.2, 7.4, and 11.5% canopy cover by 150, 250, 350, and 450 GDD°C after planting respectively, would consider replanting. </p>

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