NUCLEAR REPROGRAMMING AND ITS EPIGENETIC CONSEQUENCES IN SOMATIC CELL NUCLEAR TRANSFER DERIVED ANIMALS

Somatic cell nuclear transfer (SCNT) is a powerful tool to understand the mechanisms driving the cellular reprogramming, as well as addressing fundamental questions on developmental biology. Hundreds of animals have already been generated through this technology, however its large-scale use is still hampered by the low efficiency and disrupted phenotypes reported in SCNT derived newborns. Therefore, this review aims to expose some of the consequences often seen in cloned animals, as well as to discuss and propose some possibilities and perspectives to avoid epigenetic failures during reprogramming

Ooplast-mediated developmental rescue of bovine oocytes exposed to ethidium bromide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Ooplasm transfer has been used successfully to treat infertility in women with ooplasmic insufficiency and has culminated in the birth of healthy babies. To investigate whether mitochondrial dysfunction is a factor in ooplasmic insufficiency, bovine oocytes were exposed to ethidium bromide, an inhibitor of mitochondrial DNA replication and transcription, during in-vitro maturation (IVM). Exposure of immature oocytes to ethidium bromide for 24 h during IVM hampered meiotic resumption and the migration of cortical granules. However, a briefer treatment with ethidium bromide during the last 4 h of IVM led to partial arrest of preimplantation development without affecting oocyte maturation. Ooplasm transfer was then performed to rescue the oocytes with impaired development. In spite of this developmental hindrance, transfer of normal ooplasm into ethidium bromide-treated oocytes resulted in a complete rescue of embryonic development and the birth of heteroplasmic calves. Although this study unable to determine whether developmental rescue occurred exclusively through introduction of unaffected mitochondria into ethidium bromide-damaged oocytes, e. g. ethidium bromide may also affect other ooplasm components, these results clearly demonstrate that ooplasm transfer can completely rescue developmentally compromised oocytes, supporting the potential use of ooplasm transfer in therapeutic applications. (C) 2010, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.222172183Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2002/05054-7, 2004/01841-0, 2006/03516-4, 2006/59074-0

Immediate breast reconstruction with expander in pregnant breast cancer patients

Background: Breast reconstruction after mastectomy is currently considered an essential component in managing breast cancer patients, particularly those diagnosed at a young age. However, no studies have been published on the feasibility of immediate breast reconstruction in patients diagnosed and operated during the course of gestation. Method: We retrospectively identified all breast cancer patients who were subjected to mastectomy and immediate breast reconstruction during pregnancy at the European Institute of Oncology between 2002 and 2012. Patient demographics, gestational age at surgery, tumor stage, adjuvant treatment, details of the surgical procedures, surgical outcomes and fetal outcomes were analyzed. Results: A total of 78 patients with breast cancer diagnosed during pregnancy were subjected to a surgical procedure during the course of gestation. Twenty-two patients had mastectomy; of whom 13 were subjected to immediate breast reconstruction. Twelve out of 13 patients had a two-stage procedure with tissue expander insertion. Median gestational age at surgery was 16 weeks. No major surgical complications were encountered. Only one patient elected to have an abortion, otherwise, no spontaneous abortions or pregnancy complications were reported. Median gestational age at delivery was 35 weeks (range: 32e40 weeks). No major congenital malformations were reported. At a median follow-up of 32 months, all patients are alive with no long-term surgical complications. Conclusions: This is the first study of immediate breast reconstruction in pregnant breast cancer patients. Tissue expander insertion appears to ensure a short operative time, and does not seem to be associated with considerable morbidity to the patient or the fetus. Hence, it could be considered in the multidisciplinary management of women diagnosed with breast cancer during pregnancy

Delivery of cloned offspring: experience in Zebu cattle (Bos indicus)

The production of a healthy cloned calf is dependent on a multitude of successful steps, including reprogramming mediated by the oocyte, the development of a functional placenta, adequate maternal-fetal interaction, the establishment of a physiological metabolic setting and the formation of a complete set of well-differentiated cells that will eventually result in well-characterised and fully competent tissues and organs. Although the efficiency of nuclear transfer has improved significantly since the first report of a somatic cell nuclear transfer-derived animal, there are many descriptions of anomalies concerning cloned calves leading to high perinatal morbidity and mortality. The present article discusses some our experience regarding perinatal and neonatal procedures for cloned Zebu cattle (B. indicus) that has led to improved survival rates in Nellore cloned calves following the application of such `labour-intensive technology`

Low levels of exosomal-miRNAs in maternal blood are associated with early pregnancy loss in cloned cattle

Abstract Nuclear reprogramming mediated by somatic cell nuclear transfer (SCNT) has many applications in medicine. However, animal clones show increased rates of abortion and reduced neonatal viability. Herein, we used exosomal-miRNA profiles as a non-invasive biomarker to identify pathological pregnancies. MiRNAs play important roles in cellular proliferation and differentiation during early mammalian development. Thus, the aim of this study was to identify exosomal-miRNAs in maternal blood at 21 days of gestation that could be used for diagnosis and prognosis during early clone pregnancies in cattle. Out of 40 bovine-specific miRNAs, 27 (67.5%) were with low abundance in the C-EPL (Clone - Early pregnancy loss) group compared with the C-LTP (Clone - Late pregnancy) and AI-LTP (Artificial Insemination - Late pregnancy) groups, which had similar miRNAs levels. Bioinformatics analysis of the predicted target genes demonstrated signaling pathways and functional annotation clusters associated with critical biological processes including cell proliferation, differentiation, apoptosis, angiogenesis and embryonic development. In conclusion, our results demonstrate decreased exosomal-miRNAs in maternal blood at 21 days of gestation in cloned cattle pregnancies that failed to reach term. Furthermore, the predicted target genes regulated by these 27 miRNAs are strongly associated with pregnancy establishment and in utero embryonic development

It looks easy! Heuristics for combinatorial optimization problems.

Human performance on instances of computationally intractable optimization problems, such as the travelling salesperson problem (TSP), can be excellent. We have proposed a boundary-following heuristic to account for this finding. We report three experiments with TSPs where the capacity to employ this heuristic was varied. In Experiment 1, participants free to use the heuristic produced solutions significantly closer to optimal than did those prevented from doing so. Experiments 2 and 3 together replicated this finding in larger problems and demonstrated that a potential confound had no effect. In all three experiments, performance was closely matched by a boundary-following model. The results implicate global rather than purely local processes. Humans may have access to simple, perceptually based, heuristics that are suited to some combinatorial optimization tasks