Paulo Bayard Dias Gonçalves

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Because caspase-3 is considered a primary executioner of apoptosis and has been implicated as a mediator of luteal regression, we hypothesized that corpora lutea (CL) derived from caspase-3 null mice would exhibit a delayed onset of apoptosis during luteal regression, when compared with CL derived from wild-type (WT) mice. To test this hypothesis, ovulation(More)
There is evidence that the renin-angiotensin system plays an important role in ovulation in cattle. Using an in vivo model, we investigated the role of angiotensin (Ang) II in bovine ovulation by injecting Ang II receptor antagonists into ovulatory follicles. Animals (n = 102) were pre-synchronized and, when the follicles reached 12 mm, they were given the(More)
Angiotensin II (AngII) prevents the inhibitory effect of follicular cells on oocyte maturation, but its involvement in LH-induced meiotic resumption remains unknown. The aim of this study was to assess the involvement of AngII in LH-induced meiotic resumption and of prostaglandins (PGs) in the action of AngII. In the experiment I, seven cows were(More)
Oocytes were recovered by ovum pick up (OPU) from nine pairs of monozygotic twin German Simmental cows. The hypothesis was that there is less variability between identical twins versus among non-related individuals in the variation in the recovery of oocytes by OPU and in the efficiency of in vitro embryo production. Estrous cycles were synchronized with(More)
BACKGROUND Estradiol (E2) receptors mediate E2 effects on cell proliferation and apoptosis under normal and pathological conditions. However, the mechanisms involved in E2 signaling are not completely understood. The objectives in this study were to evaluate the expression of estrogen receptors (ESRs) during follicular selection in cattle, and the effect of(More)
OBJECTIVE To determine the behavior of isolated primordial follicles that were exposed to different concentrations of dimethyl sulfoxide (DMSO), ethylene glycol (EG), propylene glycol (PROH), and glycerol (GLY). DESIGN Isolated primordial follicles were exposed to the cryoprotectant (CPA) solution and photographed to calculate their volume at different(More)
Specific RIA systems were developed and used to measure pregnancy-associated glycoprotein (PAG) concentrations during gestation and the postpartum period in Azawak Zebu cows. Twelve females were palpated per rectum and diagnosed as pregnant. Blood samples were taken at 5-10-day intervals from approximately Week 8 of gestation until Week 10 postpartum (pp).(More)
Phosphorylated histone H2A.x (H2AX139ph) is a key factor for the repair of DNA double-strand breaks (DSBs) and the presence of H2AX139ph foci indicates the sites of DSBs. In this study, we characterized the presence of H2AX139ph during in vitro development of porcine embryos produced by IVF and somatic cell nuclear transfer (SCNT). Pronuclear stage embryos(More)
Cryopreservation of primordial follicles represents an opportunity to preserve female gametes, and consequently to protect the reproductive capacity of humans and animals, as well as to safeguard genetic material from endangered animal species or rare breeds. The aim of this work was to assess the toxicity of different concentrations of ethylene glycol (EG)(More)
Nitric oxide (NO) is a potential regulator of ovarian follicle growth, and ovarian granulosa cells reportedly generate NO in response to gonadotrophins, suggesting that the regulated form of nitric oxide synthase (iNOS) is present. The objectives of the present study were to gain insight into the expression and role of iNOS in the follicle. Messenger RNA(More)