Rodrigo Viegas - Academia.edu (original) (raw)
Papers by Rodrigo Viegas
Animal Reproduction
Cryopreservation of equine semen is crucial to semen commercialization. However, it reduces sperm... more Cryopreservation of equine semen is crucial to semen commercialization. However, it reduces sperm motility and longevity. Thus, sperm selection methods and addition of motility-activating substances to sperm, such as caffeine, may improve sperm quality of equine frozen semen. The objective of the current work was to evaluate the effects of caffeine on recovery and quality parameters of frozen-thawed sperm subjected to swim-up selection to be used in intracytoplasmic sperm injection (ICSI) in assisted reproductive techniques. Stallion semen were frozen and after thawing different caffeine concentrations were added to the samples performing four treatments control (no caffeine), 3, 5, and 7.5 mM caffeine. Sperm kinematic and motility were assessed by computer-assisted sperm analysis (CASA). Then, the four treated samples were submitted to the swim-up sperm selection, and the number of recovered sperm and morphology were evaluated at four times 20, 40, 60, and 80 min. The swim-up increased the recovery proportion of normal morphology sperm without (80.1±1%) or with caffeine addition (3mM: 81.2±1%, 5mM: 79.9±1% and 7.5 mM 78.9±1%) compared to the thawed semen (70±2%). However, the addition of 5 mM caffeine induced an increase in sperm motility (38.9±2.8 vs. 32.6±3.4%, P<0.05), and sperm recovery after swim-up (7.9x10 6 vs. 3.4x10 6 sperm/ml, P<0.05) compared to the control. The addition of 5 mM caffeine to frozen-thawed equine semen before swim-up selection improved sperm motility and increased the sperm recovery rate while not decreasing the percentage of morphologically normal sperm. Thus, caffeine addition to frozen-thawed equine semen before swim-up selection has potential clinical application in improving sperm quality for use in ICSI.
Andrologia
The aim of this study was to improve the quality of frozen‐thawed equine sperm by the addition of... more The aim of this study was to improve the quality of frozen‐thawed equine sperm by the addition of caffeine to it. Semen from nine stallions was frozen and different concentrations of caffeine (3, 5 and 7.5 mM) were added to frozen‐thawed semen. The sperm kinetic parameters, membrane functionality and integrity, and acrosome integrity and spontaneous acrosome reacted sperm were evaluated with a computer‐assisted sperm analysis, a hypoosmotic swelling test and epifluorescent microscopy, respectively. Nitrite and hydroperoxide concentrations of frozen‐thawed semen were measured using spectrophotometry. Sperm fertility was evaluated by artificial insemination (AI) of 16 mares with thawed ejaculates (control and 5 mM caffeine‐treated groups). Compared to that in the control, the addition of 5 mM caffeine induced an increase in sperm motility (38.9 ± 2.8 versus 32.6 ± 3.4%), and a decrease in nitrite concentration (11.4 ± 2.1 versus 12.8 ± 2.9 µM/µg protein, p < .05). Moreover, the pregnancy rate from AI in the caffeine group was significantly higher (62.5%) than that in the control group (12.5%). These data suggest that caffeine reduced the nitrite concentration and enhanced sperm motility in thawed equine sperm, thus increasing the fertility rate in mares inseminated with caffeine‐treated equine semen.
Cuadernos de Geografía: Revista Colombiana de Geografía, 2022
El artículo presenta una síntesis de las discusiones realizadas durante tres eventos que tuvieron... more El artículo presenta una síntesis de las discusiones realizadas durante tres eventos que tuvieron por temael heterog éneo subcampo de la cartografía social en Brasil y en América Latina. Se buscó reflexionar sobre las problemáticas suscitadas por quien elabora, desarrolla y participa de estas experiencias cartográficas. Se hizo referencia a literatura relevante, no obstante, los aportes que se presentaron surgieron de diálogos que se llevaron a cabo durante estos eventos. Se pretende contribuir a la ampliación del debate cartográfico en Brasil y en América Latina, el cual involucra las distintas perspectivas acerca de dimensiones conceptuales, epistemológicas y metodológicas de experiencias de mapeo que integran crecientemente situaciones de disputas cartográficas que se están superponiendo a disputas territoriales.
Andrologia, 2021
The objective of this study was to enhance the in vitro sperm quality and in vivo fertility of fr... more The objective of this study was to enhance the in vitro sperm quality and in vivo fertility of frozen‐thawed equine semen by the addition of l‐carnitine (LC) to post‐thawed semen. Different concentrations of LC were added to thawed samples to obtain four treatments control and 0.5, 1 and 2 mM LC. In the in vitro experiments, sperm motility and kinematics, membrane integrity and intracellular calcium ion concentration ([Ca2+]i) were investigated, and the antioxidant bioactivity of LC was assessed by measuring hydrogen peroxide and nitrite concentrations (NO2 −). The fertility rate was assessed via the artificial insemination of mares. The treatment with 1 mM LC increased sperm [Ca2+]i (60.6 ± 0.05 AU), reduced nitrite concentration (39.1 ± 14.9 µM/µg protein), increased the sperm straightness percentage (STR: 78.3 ± 5.3%) and increased the pregnancy rate (75%) as compared to the control ([Ca2+]i 48.4 ± 0.05 AU, NO2 − concentration 63.1 ± 14.4 µM/µg protein, STR 67.5 ± 7.9%, 12.5% pregnancy rate, p < 0.05). These results suggest that 1 mM LC acts as an antioxidant and stimulator of sperm metabolism in post‐thawed equine semen, increasing the fertility rate. Thus, addition of LC might be an alternative to improve the fertility of poor quality post‐thawed equine semen.
Revista Brasileira de Ciências Sociais, 2019
No presente artigo pretendemos identificar as iniciativas realizadas na esfera legislativa para a... more No presente artigo pretendemos identificar as iniciativas realizadas na esfera legislativa para a consecução da reforma do sistema de Justiça, desenvolvida no Brasil a partir dos anos 1980. Buscamos demonstrar que tais iniciativas envolvem um processo – ao contrário de uma tendência ocorrida mundialmente de enxugamento das legislações – de expansão da legislação brasileira como forma de regulamentar órgãos, métodos e instrumentos extrajudiciais de tratamento dos conflitos. Ademais, procuramos evidenciar tal processo como resultado do esforço de certos “criadores de regras” que, ao criarem e imporem regras, buscam reconfigurar o que se entende por função “pacificadora” do Estado de tratar os conflitos, justificando suas ações por meio de discursos que reforçam a via extrajudicial como maneira de tornar mais “pacífico”, “consensual” e “célere” o tratamento dos conflitos.
Desenvolvimento e Meio Ambiente, 2009
O presente artigo discute a questão ambiental na perspectiva do conflito social. Aqui lutas socia... more O presente artigo discute a questão ambiental na perspectiva do conflito social. Aqui lutas sociais envol-vendo questões ambientais são consideradas como momentos da constituição de um “campo ambiental” onde se encontram em jogo as condições de apropriação material e simbólica de bases de recursos ter-ritorializados. A noção de “campo ambiental” como um campo de forças pretende exprimir a dinâmica relacional do mundo social, onde indivíduos ou grupos sociais ocupam deferentes posições num espaço social constituído por relações, nele travando embates que põem em questão a distribuição de poder tanto material como simbólico. Os conflitos ambientais instituem assim o meio ambiente como categoria em torno da qual as práticas sociais são classificadas segundo distintos níveis de legitimidade.
Animal Reproduction
Cryopreservation of equine semen is crucial to semen commercialization. However, it reduces sperm... more Cryopreservation of equine semen is crucial to semen commercialization. However, it reduces sperm motility and longevity. Thus, sperm selection methods and addition of motility-activating substances to sperm, such as caffeine, may improve sperm quality of equine frozen semen. The objective of the current work was to evaluate the effects of caffeine on recovery and quality parameters of frozen-thawed sperm subjected to swim-up selection to be used in intracytoplasmic sperm injection (ICSI) in assisted reproductive techniques. Stallion semen were frozen and after thawing different caffeine concentrations were added to the samples performing four treatments control (no caffeine), 3, 5, and 7.5 mM caffeine. Sperm kinematic and motility were assessed by computer-assisted sperm analysis (CASA). Then, the four treated samples were submitted to the swim-up sperm selection, and the number of recovered sperm and morphology were evaluated at four times 20, 40, 60, and 80 min. The swim-up increased the recovery proportion of normal morphology sperm without (80.1±1%) or with caffeine addition (3mM: 81.2±1%, 5mM: 79.9±1% and 7.5 mM 78.9±1%) compared to the thawed semen (70±2%). However, the addition of 5 mM caffeine induced an increase in sperm motility (38.9±2.8 vs. 32.6±3.4%, P<0.05), and sperm recovery after swim-up (7.9x10 6 vs. 3.4x10 6 sperm/ml, P<0.05) compared to the control. The addition of 5 mM caffeine to frozen-thawed equine semen before swim-up selection improved sperm motility and increased the sperm recovery rate while not decreasing the percentage of morphologically normal sperm. Thus, caffeine addition to frozen-thawed equine semen before swim-up selection has potential clinical application in improving sperm quality for use in ICSI.
Andrologia
The aim of this study was to improve the quality of frozen‐thawed equine sperm by the addition of... more The aim of this study was to improve the quality of frozen‐thawed equine sperm by the addition of caffeine to it. Semen from nine stallions was frozen and different concentrations of caffeine (3, 5 and 7.5 mM) were added to frozen‐thawed semen. The sperm kinetic parameters, membrane functionality and integrity, and acrosome integrity and spontaneous acrosome reacted sperm were evaluated with a computer‐assisted sperm analysis, a hypoosmotic swelling test and epifluorescent microscopy, respectively. Nitrite and hydroperoxide concentrations of frozen‐thawed semen were measured using spectrophotometry. Sperm fertility was evaluated by artificial insemination (AI) of 16 mares with thawed ejaculates (control and 5 mM caffeine‐treated groups). Compared to that in the control, the addition of 5 mM caffeine induced an increase in sperm motility (38.9 ± 2.8 versus 32.6 ± 3.4%), and a decrease in nitrite concentration (11.4 ± 2.1 versus 12.8 ± 2.9 µM/µg protein, p < .05). Moreover, the pregnancy rate from AI in the caffeine group was significantly higher (62.5%) than that in the control group (12.5%). These data suggest that caffeine reduced the nitrite concentration and enhanced sperm motility in thawed equine sperm, thus increasing the fertility rate in mares inseminated with caffeine‐treated equine semen.
Cuadernos de Geografía: Revista Colombiana de Geografía, 2022
El artículo presenta una síntesis de las discusiones realizadas durante tres eventos que tuvieron... more El artículo presenta una síntesis de las discusiones realizadas durante tres eventos que tuvieron por temael heterog éneo subcampo de la cartografía social en Brasil y en América Latina. Se buscó reflexionar sobre las problemáticas suscitadas por quien elabora, desarrolla y participa de estas experiencias cartográficas. Se hizo referencia a literatura relevante, no obstante, los aportes que se presentaron surgieron de diálogos que se llevaron a cabo durante estos eventos. Se pretende contribuir a la ampliación del debate cartográfico en Brasil y en América Latina, el cual involucra las distintas perspectivas acerca de dimensiones conceptuales, epistemológicas y metodológicas de experiencias de mapeo que integran crecientemente situaciones de disputas cartográficas que se están superponiendo a disputas territoriales.
Andrologia, 2021
The objective of this study was to enhance the in vitro sperm quality and in vivo fertility of fr... more The objective of this study was to enhance the in vitro sperm quality and in vivo fertility of frozen‐thawed equine semen by the addition of l‐carnitine (LC) to post‐thawed semen. Different concentrations of LC were added to thawed samples to obtain four treatments control and 0.5, 1 and 2 mM LC. In the in vitro experiments, sperm motility and kinematics, membrane integrity and intracellular calcium ion concentration ([Ca2+]i) were investigated, and the antioxidant bioactivity of LC was assessed by measuring hydrogen peroxide and nitrite concentrations (NO2 −). The fertility rate was assessed via the artificial insemination of mares. The treatment with 1 mM LC increased sperm [Ca2+]i (60.6 ± 0.05 AU), reduced nitrite concentration (39.1 ± 14.9 µM/µg protein), increased the sperm straightness percentage (STR: 78.3 ± 5.3%) and increased the pregnancy rate (75%) as compared to the control ([Ca2+]i 48.4 ± 0.05 AU, NO2 − concentration 63.1 ± 14.4 µM/µg protein, STR 67.5 ± 7.9%, 12.5% pregnancy rate, p < 0.05). These results suggest that 1 mM LC acts as an antioxidant and stimulator of sperm metabolism in post‐thawed equine semen, increasing the fertility rate. Thus, addition of LC might be an alternative to improve the fertility of poor quality post‐thawed equine semen.
Revista Brasileira de Ciências Sociais, 2019
No presente artigo pretendemos identificar as iniciativas realizadas na esfera legislativa para a... more No presente artigo pretendemos identificar as iniciativas realizadas na esfera legislativa para a consecução da reforma do sistema de Justiça, desenvolvida no Brasil a partir dos anos 1980. Buscamos demonstrar que tais iniciativas envolvem um processo – ao contrário de uma tendência ocorrida mundialmente de enxugamento das legislações – de expansão da legislação brasileira como forma de regulamentar órgãos, métodos e instrumentos extrajudiciais de tratamento dos conflitos. Ademais, procuramos evidenciar tal processo como resultado do esforço de certos “criadores de regras” que, ao criarem e imporem regras, buscam reconfigurar o que se entende por função “pacificadora” do Estado de tratar os conflitos, justificando suas ações por meio de discursos que reforçam a via extrajudicial como maneira de tornar mais “pacífico”, “consensual” e “célere” o tratamento dos conflitos.
Desenvolvimento e Meio Ambiente, 2009
O presente artigo discute a questão ambiental na perspectiva do conflito social. Aqui lutas socia... more O presente artigo discute a questão ambiental na perspectiva do conflito social. Aqui lutas sociais envol-vendo questões ambientais são consideradas como momentos da constituição de um “campo ambiental” onde se encontram em jogo as condições de apropriação material e simbólica de bases de recursos ter-ritorializados. A noção de “campo ambiental” como um campo de forças pretende exprimir a dinâmica relacional do mundo social, onde indivíduos ou grupos sociais ocupam deferentes posições num espaço social constituído por relações, nele travando embates que põem em questão a distribuição de poder tanto material como simbólico. Os conflitos ambientais instituem assim o meio ambiente como categoria em torno da qual as práticas sociais são classificadas segundo distintos níveis de legitimidade.