3 resultados para CAV
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo
Resumo:
A recent molecular phylogenetic analysis (Schilling & Panero 2011) proposed to narrow the concept of the paraphyletic genus Viguiera Kunth (1818: 176; Asteraceae: Heliantheae) to embrace only the type, V. dentata (Cavanilles 1794: 10) Sprengel (1826: 615). Robinson (1977) emphasized the peculiarities of Viguiera dentata as the "distinctive and unique" presence of hairs on the filaments of the anther, the disk corollas throat less than twice as long as the lobes and densely scabrous below, a combination of features that differs from most member of the genus. During taxonomic studies of Viguiera and related genera, it was discovered that V. dentata has never been typified. The basionym, Helianthus dentatus, was described by Antonio Jose Cavanilles in Icones et Descriptiones Plantarum based on plants grown in the Real Jardin Botanico from seed sent by Martin Sesse from Mexico (Blanco 2000). Previous workers including Blake (1918) and Robinson (1977) have accepted the plate in Cavanilles as the type for Helianthus dentatus Cav.
Resumo:
Background: The in vitro production (IVP) of embryos by in vitro fertilization or cloning procedures has been known to cause epigenetic changes in the conceptus that in turn are associated with abnormalities in pre- and postnatal development. Handmade cloning (HMC) procedures and the culture of zona-free embryos in individual microwells provide excellent tools for studies in developmental biology, since embryo development and cell allocation patterns can be evaluated under a wide range of embryo reconstruction arrangements and in in vitro embryo culture conditions. As disturbances in embryonic cell allocation after in vitro embryo manipulations and unusual in vivo conditions during the first third of pregnancy appear to be associated with large offspring, embryo aggregation procedures may allow a compensation for epigenetic defects between aggregated embryos or even may influence more favorable cell allocation in embryonic lineages, favoring subsequent development. Thus, the aim of this study was to evaluate in vitro embryo developmental potential and the pattern of cell allocation in blastocysts developed after the aggregation of handmade cloned embryos produced using syngeneic wild type and/or transgenic somatic cells. Materials, Methods & Results: In vitro-matured bovine cumulus-oocyte complexes (COC) were manually bisected after cumulus and zona pellucida removal; then, two enucleated hemi-oocytes were paired and fused with either a wild type (WT) or a GFP-expressing (GFP) fetal skin cell at the 11th and 19th passages, respectively. Following chemical activation, reconstructed cloned embryos and zona-free parthenote embryos were in vitro-cultured in microwells, for 7 days, either individually (1 x 100%) or after the aggregation of two structures (2 x 100%) per microwell, as follows: (G1) one WT cloned embryo; (G2) two aggregated WT embryos; (G3) one GFP cloned embryo; (G4) two aggregated GFP embryos; (G5) aggregation of a WT embryo and a GFP embryo; (G6) one parthenote embryo; or (G7) two aggregated parthenote embryos. Fusion (clones), cleavage (Day 2), and blastocyst (Day 7) rates, and embryonic cell allocation were compared by the. 2 or Fisher tests. Total cell number (TCN) in blastocysts was analyzed by the Student's test (P < 0.05). Fusion and cleavage rates, and cell allocation were similar between groups. On a per WOW basis, development to the blastocyst stage was similar between groups, except for lower rates of development seen in G3. However, when based on number of embryos per group (one or two), blastocyst development was higher in G1 than all other groups, which were similar between one another. Cloned GFP embryos had lower in vitro development to the blastocyst stage than WT embryos, which had more TCN than parthenote or aggregated chimeric WT/GFP embryos. Aggregated GFP embryos had fewer cells than the other embryo groups. Discussion: The in vitro development of GFP cloned embryos was lower than WT embryos, with no effects on cell allocation in resulting blastocysts. Differences in blastocyst rate between groups were likely due to lower GFP-expressing cell viability, as GFP donor cells were at high population cell doublings when used for cloning. On a per embryo basis, embryo aggregation on Day 1 resulted in blastocyst development similar to non-aggregated embryos on Day 7, with no differences in cell proportion between groups. The use of GFP-expressing cells was proven a promising strategy for the study of cell allocation during embryo development, which may assist in the elucidation of mechanisms of abnormalities after in vitro embryo manipulations, leading to the development of improved protocols for the in vitro production (IVP) of bovine embryos.
Resumo:
Background. Chronic allograft vasculopathy (CAV) is an important cause of graft loss. Considering the immune inflammatory events involved in the development of CAV, therapeutic approaches to target this process are of relevance. Human amniotic fluid derived stem cells (hAFSCs), a class of fetal, pluripotent stem cells with intermediate characteristics between embryonic and adult stem cells, display immunomodulatory properties. hAFSCs express mesenchymal and embryonic markers, show high proliferation rates; however, they do not induce tumor formation, and their use does not raise ethical issues. Thus, we sought to investigate the effect of hAFSC on CAV in a model of aorta transplantation. Methods. Orthotopic aorta transplantation was performed using Fisher (F344) rats as donors and Lewis rats as recipients. Rats were divided into three groups: syngeneic (SYNG), untreated F344 receiving aorta from F344 (n = 8); allogeneic (ALLO), Lewis rats receiving allogeneic aorta from F344 (n = 8); and ALLO + hAFSC, ALLO rats treated with hAFSC (10(6) cells; n = 8). Histological analysis and immunohistochemistry were performed 30 days posttransplantation. Results. The ALLO group developed a robust aortic neointimal formation (208.7 +/- 25.4 gm) accompanied by a significant high number of ED1(+) (4845 +/- 841 cells/mm(2)) and CD43(+) cells (4064 +/- 563 cells/mm(2)), and enhanced expression of a-smooth muscle actin in the neointima (25 +/- 6%). Treatment with hAFSC diminished neointimal thickness (180.7 +/- 23.7 mu m) and induced a significant decrease of ED1(+) (1100 +/- 276 cells/mm(2)), CD43(+) cells (1080 +/- 309 cells/mu m(2)), and alpha-smooth muscle actin expression 8 +/- 3% in the neointima. Conclusions. These preliminary results showed that hAFSC suppressed inflammation and myofibroblast migration to the intima, which may contribute to ameliorate vascular changes in CAV.