Tássia Medeiros - Academia.edu (original) (raw)

Papers by Tássia Medeiros

Research paper thumbnail of Coronary Artery Disease and Oxidative Stress

Research paper thumbnail of Comparison between the health-related quality of life of children/adolescents with asthma and that of their caregivers: a systematic review and meta-analysis

Jornal Brasileiro de Pneumologia

Research paper thumbnail of 18F-FDG PET/CT and whole-body MRI diagnostic performance in M staging for non–small cell lung cancer: a systematic review and meta-analysis

Research paper thumbnail of Mild therapeutic hypothermia decreases oxidative damage and increases glutathione levels in post-cardiac arrest patients

Free Radical Biology and Medicine

Research paper thumbnail of Virtual hysterosalpingography using computed tomography, the first experiments in Brazil

Human Reproduction Archives

Objectives: This article demonstrates the virtual hysterosalpingography using computed tomography... more Objectives: This article demonstrates the virtual hysterosalpingography using computed tomography method used to perform the evaluation of tubal patency and uterine morphological alterations, which was carried out for the first time in Brazil, and our experience in this area. The techniques advantages, benefits and disadvantages compared to the traditional method are illustrated in this manuscript. Methods: 185 patients were submitted to virtual hysterosalpingography using computed tomography by a physicians indication and the results of these tests were compiled and described. Results: The advantages of virtual hysterosalpingography over X-ray hysterosalpingography are: (a) the variety of technological features offered by multi-detector tomography, (b) the injection pump and the workstations with software that allow post-processing of high-fidelity clinical images, and (c) not pinching the uterine cervix. Conclusions: Virtual hysterosalpingography is a viable alternative for the evaluation of tubal and uterine infertility factors.

Research paper thumbnail of Fluorine 18–FDG PET/CT and Diffusion-weighted MRI for Malignant versus Benign Pulmonary Lesions: A Meta-Analysis

Research paper thumbnail of Mild Therapeutic Hypothermia Increases Glutathione Levels in Postcardiac Arrest Patients

Therapeutic hypothermia and temperature management, Jan 17, 2018

Ischemia-reperfusion (I/R)-induced oxidative stress is one of the main mechanisms of tissue injur... more Ischemia-reperfusion (I/R)-induced oxidative stress is one of the main mechanisms of tissue injury after cardiac arrest (CA). A decrease in antioxidant defenses may contribute to I/R injury. The present study aims to investigate the influence of mild therapeutic hypothermia (MTH) on levels of nonenzymatic antioxidants after CA. We investigated antioxidant levels at 6, 12, 36, and 72 hours after CA in central venous blood samples of patients admitted to intensive care. The sample consisted of 31 patients under controlled normothermia (36°C) and 11 patients treated with 24 hours of MTH (33°C). Erythrocyte glutathione (GSH) levels were elevated by MTH, increasing at 6, 12, 36, and 72 hours after CA in hypothermic patients (mean GSH levels in normothermic patients: 6 hours = 73.89, 12 hours = 56.45, 36 hours = 56.46, 72 hours = 61.80 vs. hypothermic patients: 6 hours = 176.89, 12 hours = 198.78, 36 hours = 186.96, and 72 hours = 173.68 μmol/g of protein). Vitamin C levels decreased sign...

Research paper thumbnail of Therapeutic Hypothermia Reduces Oxidative Damage and Alters Antioxidant Defenses after Cardiac Arrest

Oxidative medicine and cellular longevity, 2017

After cardiac arrest, organ damage consequent to ischemia-reperfusion has been attributed to oxid... more After cardiac arrest, organ damage consequent to ischemia-reperfusion has been attributed to oxidative stress. Mild therapeutic hypothermia has been applied to reduce this damage, and it may reduce oxidative damage as well. This study aimed to compare oxidative damage and antioxidant defenses in patients treated with controlled normothermia versus mild therapeutic hypothermia during postcardiac arrest syndrome. The sample consisted of 31 patients under controlled normothermia (36°C) and 11 patients treated with 24 h mild therapeutic hypothermia (33°C), victims of in- or out-of-hospital cardiac arrest. Parameters were assessed at 6, 12, 36, and 72 h after cardiac arrest in the central venous blood samples. Hypothermic and normothermic patients had similar S100B levels, a biomarker of brain injury. Xanthine oxidase activity is similar between hypothermic and normothermic patients; however, it decreases posthypothermia treatment. Xanthine oxidase activity is positively correlated with ...

Research paper thumbnail of Ostial and Proximal Coronary Stenosis in Right Coronary with Anomalous Origin and Course: Case Report and Literature Review

ARQUIVOS BRASILEIROS DE CARDIOLOGIA - IMAGEM CARDIOVASCULAR, 2015

Research paper thumbnail of Blood markers of oxidative stress predict weaning failure from mechanical ventilation

Journal of Cellular and Molecular Medicine, 2015

Patients undergoing mechanical ventilation (MV) often experience respiratory muscle dysfunction, ... more Patients undergoing mechanical ventilation (MV) often experience respiratory muscle dysfunction, which complicates the weaning process. There is no simple means to predict or diagnose respiratory muscle dysfunction because diagnosis depends on measurements in muscle diaphragmatic fibre. As oxidative stress is a key mechanism contributing to MV-induced respiratory muscle dysfunction, the aim of this study was to determine if differences in blood measures of oxidative stress in patients who had success and failure in a spontaneous breathing trial (SBT) could be used to predict the outcome of MV. This was a prospective analysis of MV-dependent patients (≥72 hrs; n = 34) undergoing a standard weaning protocol. Clinical, laboratory and oxidative stress analyses were performed. Measurements were made on blood samples taken at three time-points: immediately before the trial, 30 min. into the trial in weaning success (WS) patients, or immediately before return to MV in weaning failure (WF) patients, and 6 hrs after the trial. We found that blood measures of oxidative stress distinguished patients who would experience WF from patients who would experience WS. Before SBT, WF patients presented higher oxidative damage in lipids and higher antioxidant levels and decreased nitric oxide concentrations. The observed differences in measures between WF and WS patients persisted throughout and after the weaning trial. In conclusion, WF may be predicted based on higher malondialdehyde, higher vitamin C and lower nitric oxide concentration in plasma.

Research paper thumbnail of Serum ferritin levels may have a pro-atherosclerotic role in coronary artery disease patients with sleep disordered breathing

Journal of Applied Biomedicine, 2015

ABSTRACT Elevated ferritin levels may lead to oxidative stress, and are associated with coronary ... more ABSTRACT Elevated ferritin levels may lead to oxidative stress, and are associated with coronary artery disease (CAD). Sleep disordered breathing (SDB) is frequently present in atherosclerosis patients, and causes endothelial dysfunction leading to atherosclerotic plaque progression. Hypoxic conditions, such as SDB, may upregulate ferritin. The aim of this study was to evaluate ferritin levels in CAD patients and to correlate ferritin levels with parameters related to CAD progression, including SDB. We studied 27 patients with CAD (defined as >30% coronary narrowing) and 29 controls. We found that ferritin was increased in CAD patients, and was positively correlated with the apnea–hypopnea index (AHI), age, C-reactive protein (CRP), transferrin, hemoglobin, and testosterone levels, and was negatively correlated with O2 saturation. Nitrites and nitrates, an indirect measure of nitric oxide (NO) concentration, were lower in CAD patients, and were negatively correlated with ferritin. The increase in ferritin may be related to oxidative stress, suggesting a possible pro-atherosclerotic role of increased ferritin in CAD patients with SDB.

Research paper thumbnail of Response to Oxidative Stress in Eight Pathogenic Yeast Species of the Genus Candida

Mycopathologia, 2010

In the course of an infection, the formation of reactive oxygen species by phagocytes and the ant... more In the course of an infection, the formation of reactive oxygen species by phagocytes and the antioxidant defense mechanisms of microorganisms play a crucial role in pathogenesis. In this study, isolates representing 8 pathogenic Candida species-Candida albicans, Candida dubliniensis, Candida famata, Candida glabrata, Candida guilliermondii, Candida krusei, Candida parapsilosis and Candida tropicalis-were compared with regard to their resistance to oxidative stress in vitro. We evaluated degree of resistance, induction of oxidative damage, capacity to adapt, and induction of antioxidant enzymes. The species showed variable sensitivity to oxidative attack. C. albicans, C. glabrata, and C. krusei were more resistant to oxidative stress under the conditions tested; C. parapsilosis and C. tropicalis presented medium resistance; and C. dubliniensis, C. famata, and C. guilliermondii were more sensitive. The overall greater resistance to oxidative stress of C. albicans and C. glabrata may provide an advantage to these species, which are the major causative agents of candidiasis.

Research paper thumbnail of Carbonyl groups: Bridging the gap between sleep disordered breathing and coronary artery disease

Free Radical Research, 2010

Sleep disordered breathing (SDB) is related to coronary artery disease (CAD), but the mechanisms ... more Sleep disordered breathing (SDB) is related to coronary artery disease (CAD), but the mechanisms are uncertain. SDB is characterized by periods of intermittent hypoxia and free radical formation. This study tested the hypothesis that carbonylation can be the link between SDB and CAD. It included 14 cases with CAD and 33 controls with <50% coronary narrowing. CAD cases have higher erythrocyte carbonyl levels than controls (p = 0.012). Positive correlation was observed between apnea-hypopnea index (AHI) and erythrocyte carbonyl concentration (rho = 0.310; p = 0.027). To predict CAD, including as regressors: AHI, erythrocyte carbonyl, gender, age and body mass index, the significant variables in the Poisson multiple regression model were AHI and erythrocytes carbonyl. An increase of 1 pmol/gHb in erythrocyte carbonyl levels increases by 1.8% the risk of CAD and one unit of AHI increases by 3.8% the risk of CAD. The present findings represent the first evidence in humans that SDB may cause CAD through protein carbonylation.

Research paper thumbnail of Oxidative stress in the kidney of reproductive male rats during aging

Experimental Gerontology, 2011

Reproduction alters the male physiology. We performed a comprehensive examination of oxidative st... more Reproduction alters the male physiology. We performed a comprehensive examination of oxidative stress in the kidneys of male rats with (experienced) or without (naïve) reproductive activity during aging. Oxidative stress was assessed by measuring the activity of catalase, glutathione peroxidase, glutathione S-transferase, and superoxide dismutase, and by measuring protein carbonylation, lipid peroxidation, nitrite and nitrate levels, vitamin C levels, and glutathione (total, reduced, and oxidized forms) levels, and metabolism was accessed by aconitase activity in kidney tissue, as well as testosterone and estradiol levels in serum. Reproductively active animals exhibited increased testosterone levels and altered metabolism. Aging affects tissues and organs and contributes to their functional decline. Elderly naïve rats showed high nitrite and nitrate levels. The experienced rats had less damage in elderly ages, probably because they had higher antioxidant amount and antioxidant enzyme activities at earlier ages, which would have avoided oxidative damage seen in naïve group, and because of the metabolism decline. Glutathione increase in naïve elder rats probably was induced for direct protection against oxidative damage and indirect protection by higher glutathione peroxidase and glutathione S-transferase activities. Linear regression shows that lipid peroxidation levels explained vitamin C levels (B standardized value of 0.42), indicating that vitamin C was properly produced or recruited into kidneys to combat lipid peroxidation. Catalase activity reflected the protein carbonylation and lipid peroxidation levels (B standardized values of 0.28 and 0.48). These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.

Research paper thumbnail of Oxidative stress in the brain of reproductive male rats during aging

Experimental Gerontology, 2011

Reproduction alters the male physiology. We performed a comprehensive study to examine oxidative ... more Reproduction alters the male physiology. We performed a comprehensive study to examine oxidative stress in the brains of male rats with (experienced) or without (naïve) reproductive activity during aging. Oxidative stress was assessed by measuring the activity of catalase, glutathione peroxidase, superoxide dismutase, glutathione S-transferase, aconitase, and aconitase reactivated, and by measuring lipid peroxidation, protein carbonylation, nitrite and nitrate levels, vitamin C levels, and glutathione (total, reduced, oxidized forms) levels in brain tissue, as well as testosterone and estradiol levels in serum. Reproductively active animals exhibited increased testosterone levels and aconitase activity, suggesting an increased metabolism. Increased antioxidant enzyme activities and increased levels of antioxidant compounds were observed, yet damage to biomolecules was also observed in experienced rats. During aging changes in oxidative stress were observed. We found higher activities of antioxidant enzymes, higher amounts of antioxidants, and more damage at six months of age among experienced animals than among naïve animals. Similar antioxidant activities and levels, and damage were found between the groups at twenty-four months of age. These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.

Research paper thumbnail of Response to Oxidative Stress in Eight Pathogenic Yeast Species of the Genus Candida

Mycopathologia, 2010

In the course of an infection, the formation of reactive oxygen species by phagocytes and the ant... more In the course of an infection, the formation of reactive oxygen species by phagocytes and the antioxidant defense mechanisms of microorganisms play a crucial role in pathogenesis. In this study, isolates representing 8 pathogenic Candida species-Candida albicans, Candida dubliniensis, Candida famata, Candida glabrata, Candida guilliermondii, Candida krusei, Candida parapsilosis and Candida tropicalis-were compared with regard to their resistance to oxidative stress in vitro. We evaluated degree of resistance, induction of oxidative damage, capacity to adapt, and induction of antioxidant enzymes. The species showed variable sensitivity to oxidative attack. C. albicans, C. glabrata, and C. krusei were more resistant to oxidative stress under the conditions tested; C. parapsilosis and C. tropicalis presented medium resistance; and C. dubliniensis, C. famata, and C. guilliermondii were more sensitive. The overall greater resistance to oxidative stress of C. albicans and C. glabrata may provide an advantage to these species, which are the major causative agents of candidiasis.

Research paper thumbnail of Coronary Artery Disease and Oxidative Stress

Research paper thumbnail of Comparison between the health-related quality of life of children/adolescents with asthma and that of their caregivers: a systematic review and meta-analysis

Jornal Brasileiro de Pneumologia

Research paper thumbnail of 18F-FDG PET/CT and whole-body MRI diagnostic performance in M staging for non–small cell lung cancer: a systematic review and meta-analysis

Research paper thumbnail of Mild therapeutic hypothermia decreases oxidative damage and increases glutathione levels in post-cardiac arrest patients

Free Radical Biology and Medicine

Research paper thumbnail of Virtual hysterosalpingography using computed tomography, the first experiments in Brazil

Human Reproduction Archives

Objectives: This article demonstrates the virtual hysterosalpingography using computed tomography... more Objectives: This article demonstrates the virtual hysterosalpingography using computed tomography method used to perform the evaluation of tubal patency and uterine morphological alterations, which was carried out for the first time in Brazil, and our experience in this area. The techniques advantages, benefits and disadvantages compared to the traditional method are illustrated in this manuscript. Methods: 185 patients were submitted to virtual hysterosalpingography using computed tomography by a physicians indication and the results of these tests were compiled and described. Results: The advantages of virtual hysterosalpingography over X-ray hysterosalpingography are: (a) the variety of technological features offered by multi-detector tomography, (b) the injection pump and the workstations with software that allow post-processing of high-fidelity clinical images, and (c) not pinching the uterine cervix. Conclusions: Virtual hysterosalpingography is a viable alternative for the evaluation of tubal and uterine infertility factors.

Research paper thumbnail of Fluorine 18–FDG PET/CT and Diffusion-weighted MRI for Malignant versus Benign Pulmonary Lesions: A Meta-Analysis

Research paper thumbnail of Mild Therapeutic Hypothermia Increases Glutathione Levels in Postcardiac Arrest Patients

Therapeutic hypothermia and temperature management, Jan 17, 2018

Ischemia-reperfusion (I/R)-induced oxidative stress is one of the main mechanisms of tissue injur... more Ischemia-reperfusion (I/R)-induced oxidative stress is one of the main mechanisms of tissue injury after cardiac arrest (CA). A decrease in antioxidant defenses may contribute to I/R injury. The present study aims to investigate the influence of mild therapeutic hypothermia (MTH) on levels of nonenzymatic antioxidants after CA. We investigated antioxidant levels at 6, 12, 36, and 72 hours after CA in central venous blood samples of patients admitted to intensive care. The sample consisted of 31 patients under controlled normothermia (36°C) and 11 patients treated with 24 hours of MTH (33°C). Erythrocyte glutathione (GSH) levels were elevated by MTH, increasing at 6, 12, 36, and 72 hours after CA in hypothermic patients (mean GSH levels in normothermic patients: 6 hours = 73.89, 12 hours = 56.45, 36 hours = 56.46, 72 hours = 61.80 vs. hypothermic patients: 6 hours = 176.89, 12 hours = 198.78, 36 hours = 186.96, and 72 hours = 173.68 μmol/g of protein). Vitamin C levels decreased sign...

Research paper thumbnail of Therapeutic Hypothermia Reduces Oxidative Damage and Alters Antioxidant Defenses after Cardiac Arrest

Oxidative medicine and cellular longevity, 2017

After cardiac arrest, organ damage consequent to ischemia-reperfusion has been attributed to oxid... more After cardiac arrest, organ damage consequent to ischemia-reperfusion has been attributed to oxidative stress. Mild therapeutic hypothermia has been applied to reduce this damage, and it may reduce oxidative damage as well. This study aimed to compare oxidative damage and antioxidant defenses in patients treated with controlled normothermia versus mild therapeutic hypothermia during postcardiac arrest syndrome. The sample consisted of 31 patients under controlled normothermia (36°C) and 11 patients treated with 24 h mild therapeutic hypothermia (33°C), victims of in- or out-of-hospital cardiac arrest. Parameters were assessed at 6, 12, 36, and 72 h after cardiac arrest in the central venous blood samples. Hypothermic and normothermic patients had similar S100B levels, a biomarker of brain injury. Xanthine oxidase activity is similar between hypothermic and normothermic patients; however, it decreases posthypothermia treatment. Xanthine oxidase activity is positively correlated with ...

Research paper thumbnail of Ostial and Proximal Coronary Stenosis in Right Coronary with Anomalous Origin and Course: Case Report and Literature Review

ARQUIVOS BRASILEIROS DE CARDIOLOGIA - IMAGEM CARDIOVASCULAR, 2015

Research paper thumbnail of Blood markers of oxidative stress predict weaning failure from mechanical ventilation

Journal of Cellular and Molecular Medicine, 2015

Patients undergoing mechanical ventilation (MV) often experience respiratory muscle dysfunction, ... more Patients undergoing mechanical ventilation (MV) often experience respiratory muscle dysfunction, which complicates the weaning process. There is no simple means to predict or diagnose respiratory muscle dysfunction because diagnosis depends on measurements in muscle diaphragmatic fibre. As oxidative stress is a key mechanism contributing to MV-induced respiratory muscle dysfunction, the aim of this study was to determine if differences in blood measures of oxidative stress in patients who had success and failure in a spontaneous breathing trial (SBT) could be used to predict the outcome of MV. This was a prospective analysis of MV-dependent patients (≥72 hrs; n = 34) undergoing a standard weaning protocol. Clinical, laboratory and oxidative stress analyses were performed. Measurements were made on blood samples taken at three time-points: immediately before the trial, 30 min. into the trial in weaning success (WS) patients, or immediately before return to MV in weaning failure (WF) patients, and 6 hrs after the trial. We found that blood measures of oxidative stress distinguished patients who would experience WF from patients who would experience WS. Before SBT, WF patients presented higher oxidative damage in lipids and higher antioxidant levels and decreased nitric oxide concentrations. The observed differences in measures between WF and WS patients persisted throughout and after the weaning trial. In conclusion, WF may be predicted based on higher malondialdehyde, higher vitamin C and lower nitric oxide concentration in plasma.

Research paper thumbnail of Serum ferritin levels may have a pro-atherosclerotic role in coronary artery disease patients with sleep disordered breathing

Journal of Applied Biomedicine, 2015

ABSTRACT Elevated ferritin levels may lead to oxidative stress, and are associated with coronary ... more ABSTRACT Elevated ferritin levels may lead to oxidative stress, and are associated with coronary artery disease (CAD). Sleep disordered breathing (SDB) is frequently present in atherosclerosis patients, and causes endothelial dysfunction leading to atherosclerotic plaque progression. Hypoxic conditions, such as SDB, may upregulate ferritin. The aim of this study was to evaluate ferritin levels in CAD patients and to correlate ferritin levels with parameters related to CAD progression, including SDB. We studied 27 patients with CAD (defined as >30% coronary narrowing) and 29 controls. We found that ferritin was increased in CAD patients, and was positively correlated with the apnea–hypopnea index (AHI), age, C-reactive protein (CRP), transferrin, hemoglobin, and testosterone levels, and was negatively correlated with O2 saturation. Nitrites and nitrates, an indirect measure of nitric oxide (NO) concentration, were lower in CAD patients, and were negatively correlated with ferritin. The increase in ferritin may be related to oxidative stress, suggesting a possible pro-atherosclerotic role of increased ferritin in CAD patients with SDB.

Research paper thumbnail of Response to Oxidative Stress in Eight Pathogenic Yeast Species of the Genus Candida

Mycopathologia, 2010

In the course of an infection, the formation of reactive oxygen species by phagocytes and the ant... more In the course of an infection, the formation of reactive oxygen species by phagocytes and the antioxidant defense mechanisms of microorganisms play a crucial role in pathogenesis. In this study, isolates representing 8 pathogenic Candida species-Candida albicans, Candida dubliniensis, Candida famata, Candida glabrata, Candida guilliermondii, Candida krusei, Candida parapsilosis and Candida tropicalis-were compared with regard to their resistance to oxidative stress in vitro. We evaluated degree of resistance, induction of oxidative damage, capacity to adapt, and induction of antioxidant enzymes. The species showed variable sensitivity to oxidative attack. C. albicans, C. glabrata, and C. krusei were more resistant to oxidative stress under the conditions tested; C. parapsilosis and C. tropicalis presented medium resistance; and C. dubliniensis, C. famata, and C. guilliermondii were more sensitive. The overall greater resistance to oxidative stress of C. albicans and C. glabrata may provide an advantage to these species, which are the major causative agents of candidiasis.

Research paper thumbnail of Carbonyl groups: Bridging the gap between sleep disordered breathing and coronary artery disease

Free Radical Research, 2010

Sleep disordered breathing (SDB) is related to coronary artery disease (CAD), but the mechanisms ... more Sleep disordered breathing (SDB) is related to coronary artery disease (CAD), but the mechanisms are uncertain. SDB is characterized by periods of intermittent hypoxia and free radical formation. This study tested the hypothesis that carbonylation can be the link between SDB and CAD. It included 14 cases with CAD and 33 controls with <50% coronary narrowing. CAD cases have higher erythrocyte carbonyl levels than controls (p = 0.012). Positive correlation was observed between apnea-hypopnea index (AHI) and erythrocyte carbonyl concentration (rho = 0.310; p = 0.027). To predict CAD, including as regressors: AHI, erythrocyte carbonyl, gender, age and body mass index, the significant variables in the Poisson multiple regression model were AHI and erythrocytes carbonyl. An increase of 1 pmol/gHb in erythrocyte carbonyl levels increases by 1.8% the risk of CAD and one unit of AHI increases by 3.8% the risk of CAD. The present findings represent the first evidence in humans that SDB may cause CAD through protein carbonylation.

Research paper thumbnail of Oxidative stress in the kidney of reproductive male rats during aging

Experimental Gerontology, 2011

Reproduction alters the male physiology. We performed a comprehensive examination of oxidative st... more Reproduction alters the male physiology. We performed a comprehensive examination of oxidative stress in the kidneys of male rats with (experienced) or without (naïve) reproductive activity during aging. Oxidative stress was assessed by measuring the activity of catalase, glutathione peroxidase, glutathione S-transferase, and superoxide dismutase, and by measuring protein carbonylation, lipid peroxidation, nitrite and nitrate levels, vitamin C levels, and glutathione (total, reduced, and oxidized forms) levels, and metabolism was accessed by aconitase activity in kidney tissue, as well as testosterone and estradiol levels in serum. Reproductively active animals exhibited increased testosterone levels and altered metabolism. Aging affects tissues and organs and contributes to their functional decline. Elderly naïve rats showed high nitrite and nitrate levels. The experienced rats had less damage in elderly ages, probably because they had higher antioxidant amount and antioxidant enzyme activities at earlier ages, which would have avoided oxidative damage seen in naïve group, and because of the metabolism decline. Glutathione increase in naïve elder rats probably was induced for direct protection against oxidative damage and indirect protection by higher glutathione peroxidase and glutathione S-transferase activities. Linear regression shows that lipid peroxidation levels explained vitamin C levels (B standardized value of 0.42), indicating that vitamin C was properly produced or recruited into kidneys to combat lipid peroxidation. Catalase activity reflected the protein carbonylation and lipid peroxidation levels (B standardized values of 0.28 and 0.48). These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.

Research paper thumbnail of Oxidative stress in the brain of reproductive male rats during aging

Experimental Gerontology, 2011

Reproduction alters the male physiology. We performed a comprehensive study to examine oxidative ... more Reproduction alters the male physiology. We performed a comprehensive study to examine oxidative stress in the brains of male rats with (experienced) or without (naïve) reproductive activity during aging. Oxidative stress was assessed by measuring the activity of catalase, glutathione peroxidase, superoxide dismutase, glutathione S-transferase, aconitase, and aconitase reactivated, and by measuring lipid peroxidation, protein carbonylation, nitrite and nitrate levels, vitamin C levels, and glutathione (total, reduced, oxidized forms) levels in brain tissue, as well as testosterone and estradiol levels in serum. Reproductively active animals exhibited increased testosterone levels and aconitase activity, suggesting an increased metabolism. Increased antioxidant enzyme activities and increased levels of antioxidant compounds were observed, yet damage to biomolecules was also observed in experienced rats. During aging changes in oxidative stress were observed. We found higher activities of antioxidant enzymes, higher amounts of antioxidants, and more damage at six months of age among experienced animals than among naïve animals. Similar antioxidant activities and levels, and damage were found between the groups at twenty-four months of age. These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.

Research paper thumbnail of Response to Oxidative Stress in Eight Pathogenic Yeast Species of the Genus Candida

Mycopathologia, 2010

In the course of an infection, the formation of reactive oxygen species by phagocytes and the ant... more In the course of an infection, the formation of reactive oxygen species by phagocytes and the antioxidant defense mechanisms of microorganisms play a crucial role in pathogenesis. In this study, isolates representing 8 pathogenic Candida species-Candida albicans, Candida dubliniensis, Candida famata, Candida glabrata, Candida guilliermondii, Candida krusei, Candida parapsilosis and Candida tropicalis-were compared with regard to their resistance to oxidative stress in vitro. We evaluated degree of resistance, induction of oxidative damage, capacity to adapt, and induction of antioxidant enzymes. The species showed variable sensitivity to oxidative attack. C. albicans, C. glabrata, and C. krusei were more resistant to oxidative stress under the conditions tested; C. parapsilosis and C. tropicalis presented medium resistance; and C. dubliniensis, C. famata, and C. guilliermondii were more sensitive. The overall greater resistance to oxidative stress of C. albicans and C. glabrata may provide an advantage to these species, which are the major causative agents of candidiasis.