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Presidencia Roque Saenz Pena, Argentina

Catalano M.I.,National University of Buenos Aires Northeast Province | Paradell S.L.,National University of La Plata | Dietrich C.H.,University of Illinois at Urbana - Champaign
Zootaxa | Year: 2014

The Neotropical microleafhopper genera Paulomanus and Beamerana are redescribed based on study of type material and newly collected specimens. Paulomanus is recorded for the first time from Argentina and a new species, P. falciformis n. sp., is described. Detailed morphological description and illustration of the new species and a key to males of the known species of Paulomanus are provided. A key to genera of the New World Empoascini is also provided. Copyright © 2014 Magnolia Press.

Semeniuk M.B.,National University of La Plata | Merino M.L.,National University of Buenos Aires Northeast Province
Mammalia | Year: 2015

Pampas deer (Ozotoceros bezoarticus) is a medium-sized South American cervid associated with savannas and grasslands in Argentina, Brazil, Bolivia, Uruguay, and Paraguay. Currently, four isolated population nuclei occur in Argentina, with the largest one located in the semiarid grasslands of San Luis Province. The aim of this work was to describe the social organization of this local population and to determine and analyze the factors that influence it. The most frequent groups found were mixed groups (34.82%), followed by solitary males (18.64%), and solitary females (15.00%). Differences in group type occurrence were found in three periods: dry, early rainy, and late rainy seasons. Mixed groups were more frequent during the dry season. The sexual segregation-aggregation statistic showed statistically significant segregation only in January and November. In addition, we analyzed the social grouping patterns during an annual cycle; the mean group size was 2.49±0.46 and Jarman's typical group size was 3.84±1.08 (individuals/group). A mixed-model nested ANOVA showed marked differences in terms of group sizes between habitat types and seasons. The social organization of the Pampas deer in San Luis is similar to that of the other populations of this species, despite occupying a different environment type and exhibiting disparate feeding styles and density values. © 2015 by De Gruyter.

Luque G.M.,CONICET | Perez-Millan M.I.,CONICET | Ornstein A.M.,CONICET | Cristina C.,National University of Buenos Aires Northeast Province | Becu-Villalobos D.,CONICET
Journal of Pharmacology and Experimental Therapeutics | Year: 2011

Prolactin-secreting adenomas are the most frequent type among pituitary tumors, and pharmacological therapy with dopamine agonists remains the mainstay of treatment. But some adenomas are resistant, and a decrease in the number or function of dopamine D2 receptors (D2Rs) has been described in these cases. D2R knockout [Drd2(-/-)] mice have chronic hyperprolactinemia and pituitary hyperplasia and provide an experimental model for dopamine agonist-resistant prolactinomas. We described previously that disruption of D2Rs increases vascular endothelial growth factor (VEGF) expression. We therefore designed two strategies of antiangiogenesis using prolactinomas generated in Drd2(-/-) female mice: direct intra-adenoma mVEGF R1 (Flt-1)/Fc chimera (VEGF-TRAP) injection for 3 weeks [into subcutaneously transplanted pituitaries from Drd2(-/-) mice] and systemic VEGF neutralization with the specific monoclonal antibody G6-31. Both strategies resulted in substantial decrease of prolactin content and lactotrope area, and a reduction in tumor size was observed in in situ prolactinomas. There were significant decreases in vascularity, evaluated by cluster of differentiation molecule 31 vessel staining, and proliferation (proliferating cell nuclear antigen staining) in response to both anti-VEGF treatments. These data demonstrate that the antiangiogenic approach was effective in inhibiting the growth of in situ dopamine-resistant prolactinomas as well as in the transplanted adenomas. No differences in VEGF protein expression were observed after either anti-VEGF treatment, and, although serum VEGF was increased in G6-31-treated mice, pituitary activation of the VEGF receptor 2 signaling pathway was reduced. Our results indicate that, even though the role of angiogenesis in pituitary adenomas is contentious, VEGF might contribute to adequate vascular supply and represent a supplementary therapeutic target in dopamine agonist-resistant prolactinomas. Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics.

Darriba G.N.,National University of La Plata | Munoz E.L.,National University of La Plata | Errico L.A.,National University of La Plata | Errico L.A.,National University of Buenos Aires Northeast Province | Renteria M.,National University of La Plata
Journal of Physical Chemistry C | Year: 2014

A detailed theoretical first-principles study of structural, electronic, and hyperfine properties at Sn and Ta sites of undoped and Ta-doped rutile SnO2 is presented, using the Full-Potential Augmented Plane Wave plus local orbitals (FP-APW+lo) method. In the Ta-doped systems, we performed calculations for two different charge states. The predicted electric-field- gradient (EFG) tensor, the key magnitude in this study, for both charge states of the impurity result to be almost equal and in good agreement with Time-Differential Perturbed γ-γ Angular Correlation (TDPAC) results in 181Ta-doped SnO2 thin films. This study enables at present to discuss the origin of the EFG and the role played by the structural anisotropic contractions introduced by the Ta atom and the impurity charge state on the hyperfine properties. To determine the correct charge state of the impurity, we performed energetic studies, predicting the metallic behavior of degenerate semiconductors, in agreement with resistivity experimental results obtained in samples with the same Ta dilution. © 2014 American Chemical Society.

Sterkel M.,National University of La Plata | Urlaub H.,Max Planck Institute for Biophysical Chemistry | Rivera-Pomar R.,National University of La Plata | Rivera-Pomar R.,National University of Buenos Aires Northeast Province | Ons S.,National University of La Plata
Journal of Proteome Research | Year: 2011

In hematophagous insects, blood intake triggers a prompt response mediated by neuropeptides, which regulates a variety of physiological processes. Here we report a quantitative proteomic analysis of the postfeeding response in the central nervous system of Rhodnius prolixus, a vector of Chagas disease. The concentration of neuropeptides NVP-like, ITG-like, kinin-precursor peptide, and neuropeptide-like precursor 1 (NPLP1) significantly changes in response to blood intake. We also performed a neuropeptidomic analysis of other feeding-related organs, namely salivary glands and gut. We identified NPLP1 in salivary glands and myosuppressin in midgut. This is the first report suggesting a role for NPLP1, involving the peptides processed from this precursor in the hormonal control of the production and/or release of saliva. Our results contribute to the understanding of the postprandial neuroendocrine response in hematophagous and provide important information for physiological and pharmacological studies aimed to the design of next-generation insecticides such as peptidomimetics. © 2011 American Chemical Society.

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