126 research outputs found
Relação entre infecção urinåria e problemas puerperais em porcas.
bitstream/CNPSA/15873/1/publicacao_v2v50v.pd
High-speed video and electromagnetic analysis of two natural bipolar cloud-to-ground lightning flashes
High-speed video records of two bipolar cloud-to-ground flashes were analyzed in detail.\ud
They both began with a single positive return stroke that was followed by more than one subsequent weak\ud
negative stroke. Due to the elevated cloud base height of its parent thunderstorm, the preparatory processes\ud
of each subsequent negative stroke were documented optically below cloud base. In the first event (Case 1) it\ud
was observed that all four subsequent negative strokes were initiated by recoil leaders that retraced one\ud
horizontal channel segment previously ionized by the positive leader. Those recoil leaders connected to the\ud
original vertical channel segment and propagated toward ground, producing four subsequent strokes that\ud
had the same ground contact point as the original positive discharge. The second event (Case 2), in contrast,\ud
presented 15 subsequent strokes that were initiated by recoil leaders that did not reach the original channel\ud
of the positive stroke. They diverged vertically toward ground, making contact approximately 11 km away\ud
from the original positive strike point. These results constitute the first optical evidence that both single- and\ud
multiple-channel bipolar flashes occur as a consequence of recoil leader activity in the branches of the initial\ud
positive return stroke. For both events their total channel length increased continuously at a rate of the order\ud
of 104 m s 1, comparable to speeds reported for typical positive leaders.FAPESP - 08/56711-4, 2010/01742-2FAPESP - CHUVA project - 2009/15235-8UNIVAP - Universidade do Vale do ParaĂb
TAT-Mediated Transduction of MafA Protein In Utero Results in Enhanced Pancreatic Insulin Expression and Changes in Islet Morphology
Alongside Pdx1 and Beta2/NeuroD, the transcription factor MafA has been shown to be instrumental in the maintenance of the beta cell phenotype. Indeed, a combination of MafA, Pdx1 and Ngn3 (an upstream regulator of Beta2/NeuroD) was recently reported to lead to the effective reprogramming of acinar cells into insulin-producing beta cells. These experiments set the stage for the development of new strategies to address the impairment of glycemic control in diabetic patients. However, the clinical applicability of reprogramming in this context is deemed to be poor due to the need to use viral vehicles for the delivery of the above factors. Here we describe a recombinant transducible version of the MafA protein (TAT-MafA) that penetrates across cell membranes with an efficiency of 100% and binds to the insulin promoter in vitro. When injected in utero into living mouse embryos, TAT-MafA significantly up-regulates target genes and induces enhanced insulin production as well as cytoarchitectural changes consistent with faster islet maturation. As the latest addition to our armamentarium of transducible proteins (which already includes Pdx1 and Ngn3), the purification and characterization of a functional TAT-MafA protein opens the door to prospective therapeutic uses that circumvent the use of viral delivery. To our knowledge, this is also the first report on the use of protein transduction in utero
Pig-to-Nonhuman Primates Pancreatic Islet Xenotransplantation: An Overview
The therapy of type 1 diabetes is an open challenging problem. The restoration of normoglycemia and insulin independence in immunosuppressed type 1 diabetic recipients of islet allotransplantation has shown the potential of a cell-based diabetes therapy. Even if successful, this approach poses a problem of scarce tissue supply. Xenotransplantation can be the answer to this limited donor availability and, among possible candidate tissues for xenotransplantation, porcine islets are the closest to a future clinical application. Xenotransplantation, with pigs as donors, offers the possibility of using healthy, living, and genetically modified islets from pathogen-free animals available in unlimited number of islets. Several studies in the pig-to-nonhuman primate model demonstrated the feasibility of successful preclinical islet xenotransplantation and have provided insights into the critical events and possible mechanisms of immune recognition and rejection of xenogeneic islet grafts. Particularly promising results in the achievement of prolonged insulin independence were obtained with newly developed, genetically modified pigs islets able to produce immunoregulatory products, using different implantation sites, and new immunotherapeutic strategies. Nonetheless, further efforts are needed to generate additional safety and efficacy data in nonhuman primate models to safely translate these findings into the clinic
- âŠ