Publications by authors named "Maira M Brito"

Uterine vascular alterations take place in pyometra bitches speculatively influenced by prostaglandin and nitric oxide pathways. However, no causative effect of nitric oxide on endometrial vascularization was proved elsewhere for medically treated pyometra bitches. This study aimed to identify the main in situ uterine artery vasodilation pathway in pyometra bitches medically treated with antigestagen solely or coupled with prostaglandin.

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In premature births, deficiency and/or inactivation of surfactant and incomplete development of lung occur, leading to pulmonary complications and greater need for ventilatory interventions. Prenatal corticosteroid therapy is used to improve neonatal lung function and, thus, may reduce mortality and lower incidence and severity of lung injury. Therefore, this study aimed to assess the need for ventilatory support in preterm lambs subjected or not to prenatal betamethasone treatment, and to evaluate the effectiveness on neonatal survival.

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The success of immediate adaptation to extrauterine life depends on appropriate lung function, however, elective cesarean section can increase the risk of respiratory distress as a result of reduced pulmonary fluid absorption. This study aimed to evaluate the influence of birth mode on pulmonary clearance and respiratory performance of canine neonates in the transition period. For this purpose, 37 neonates were selected according to the obstetric condition: Vaginal Eutocia (n = 17) and Elective C-section (n = 20).

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Increased fetal cortisol is associated with catecholamine release, a primary factor for neonatal adaptive responses. However, relationship between canine peripartum cortisol and catecholamine is unknown. We aimed to compare serum adrenaline, noradrenaline and cortisol during peripartum in bitches and neonates of distinct obstetric conditions and to assess amniotic fluid cortisol concentration.

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Benign Prostatic Hyperplasia (BPH) is a pathological condition that directly interferes with the reproductive potential of senile dogs, by leading to prostate enlargement and sperm injury, which in turn may compromise sperm freezeability. Moreover, albeit finasteride treatment reduces prostatic volume and blood supply and maintains seminal quality and testicular integrity, the effects of sperm samples submitted to cryopreservation after the finasteride treatment are still unknown. Thus, the aim of this study was to evaluate frozen-thawed semen of BPH dogs, as well as dogs subjected to BPH pharmacological treatment with finasteride.

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Challenges of the extrauterine environment can be life threatening for a premature fetus with inadequate fetal maturity. Maternal corticosteroids therapy is widely employed to induce fetal pulmonary maturation. Nevertheless, whenever therapeutic pregnancy interruption has to be performed in a time manner insufficient to treat the dam, postnatal corticotherapy can be considered an alternative.

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Background: The influence of birth mode on redox balance is unknown in dogs. We aimed to compare antioxidant activity and oxidative stress of puppies born by elective c-section or vaginal delivery.

Methods: Twenty-one bitches were elected for spontaneous vaginal delivery (n = 10) and elective cesarean section (n = 11) groups, considering only the first and last puppies born.

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Senescence leads to deleterious effects in testicular function, sperm quality and fertility in dogs. There, however, are no consistent results of vascular changes in the testes and epididymis during natural ageing in dogs. The aim of this study, therefore, was to compare testes and epididymis blood flow, biometry and echodensity between young and senile dogs.

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Cystic endometrial hyperplasia-pyometra complex is a canine endometrial disorder, considered the most common and important among uterine diseases. The treatment of choice is ovariohysterectomy, but medical treatments have become an alternative. However, no studies have been performed in order to evaluate uterine hemodynamic changes during medical treatment for pyometra bitches.

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Article Synopsis
  • Benign prostatic hyperplasia (BPH) is a common reproductive disorder in older dogs, and treatments like orchiectomy and finasteride aim to alleviate symptoms and reduce prostate size.
  • A study assessed the effects of BPH and short-term finasteride therapy on various parameters in dogs, using groups that were either affected by BPH or not, with and without finasteride treatment.
  • Results showed that while BPH led to hormonal changes and affected sperm quality, short-term finasteride treatment helped lower certain hormone levels and improved testicular blood flow without harming semen quality, indicating its potential as a therapeutic option for BPH in dogs.
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As a consequence of a hormonal imbalance, Prostatic Hyperplasia (PH) is characterized by increased prostate volume, along with higher local angiogenesis and vascularization. Orchiectomy is the common treatment for dogs, however it is not an option for breeding animals. Thus, finasteride arises as the drug of choice for stud dogs.

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Background: In newborns, exposure to the extrauterine environment with high oxygen tension and sudden pulmonary adaptation leads to an increase in reactive oxygen species (ROS). ROS have several physiological roles, which are essential for neonatal development, however, when unbalanced, these highly unstable molecules can cause cellular destabilisation, compromising vital processes.

Objectives: To characterise the oxidative status in healthy equine neonates, evaluating an indicator of lipid peroxidation and both enzymatic and nonenzymatic antioxidant systems, during the first week of life.

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In order to add information to physiology of sperm maturation and help to underline future antioxidant supplementation treatment to epididymal sperm, the aim of this study was to evaluate susceptibility of caput, corpus and cauda epididymal sperm to different reactive oxygen species (ROS) in dogs. Epididymal sperm was separately collected from each segment (caput, corpus and cauda) and subjected to 4 different ROS-challenges: superoxide anion, hydrogen peroxide, hydroxyl radical, malondialdehyde (MDA) or maintained as control. After 30 min of incubation in each ROS, sperm was evaluated for sperm kinetics, plasma and acrossomal membrane integrity, mitochondrial activity and resistance to oxidative stress.

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The aim of this study was to compare fresh and post-thaw sperm morphofunctionality of young and old dogs of a case trial study. Young dogs had higher libido and fresh semen motility, vigour and plasmatic membrane integrity. Conversely, senile dogs had higher percentage of major sperm defects (proximal droplets).

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The present research aimed to compare the hormonal profile, sperm quality and freezability of young and senile dogs. Dogs were assigned into Young Group ( = 11) and Senile Group ( = 11), additionally divided into Fresh Semen Group and Cryopreserved Semen Group. Males were evaluated for libido score and blood estrogen and testosterone assay.

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Taurine bulls are highly susceptible to heat stress, leading to increased oxidative stress (OS) and impaired sperm viability. Polyunsaturated fatty acids (PUFAs) supplementation can be an alternative to improve semen quality, which also results in more sperm susceptibility to lipid peroxidation. Moreover, this deleterious effect can be exacerbated in animals affected by heat stress.

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In addition to the existence of several cryopreservation protocols, no systematic research has been carried out in order to confirm the suitable protocol for canine sperm. This study aims to assess the effect of adding 5% glycerol during cryopreservation at 37°C (one-step) and 5°C (two-steps), in addition of testing two thawing protocols (37°C for 30 seconds, and 70°C for 8 seconds). We used 12 sperm samples divided into four experimental groups: Single-Step - Slow Thawing Group; Two-Step - Slow Thawing Group; Single-Step - Fast Thawing Group; and Two-Step - Fast Thawing Group.

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