N(omega)-nitro-L-arginine methyl ester (L-NAME) decreases the vasodilator effect of nitric oxide (NO) and induces pre-eclampsia in mouse. Sildenafil inhibits the degradation of nitric oxide and increases vasodilation. This study aimed to determine the effects of sildenafil citrate on angiogenesis and oxidative stress at the maternal foetal interface on pre-eclampsia-like mouse model induced by L-NAME. Twenty pregnant mice were divided into four groups: (i) vehicle control; (ii) L-NAME; (iii) sildenafil; (4) L-NAME+sildenafil. L-NAME was administered from day 7 of pregnancy and sildenafil from day 8 until day 16; animals were euthanized on day 17. Placental and foetal sizes and weights were measured; lipid peroxide levels and catalase activity in placental homogenates were determined, and placental vascular endothelia were identified by lectin-histochemistry using BSA-I lectin. Western blot analysis was used to determine VEGF expression in placental homogenates. No changes were seen in placental and foetal development in mice with normal pregnancies treated with sildenafil. Treatments with L-NAME reduced significantly the placental weight and average height and decreased the percentage of the endothelial surface. These alterations may be mediated by the reduction of NO levels in trophoblastic cells, due to the inhibitory effect of L-NAME on nitric oxide synthase (NOS) synthesis. This effect was offset by the treatment with sildenafil, with an increase in the percentage of the endothelial surface. In conclusion, our results indicate that treatment with sildenafil on pre-eclampsia mouse model can be used without adverse effects on the concept and its use in the treatment of pre-eclampsia is promising.

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The present work aimed to study the properties of a novel nanocomposite with promising biomedical applications. Nanocomposites were prepared by the addition of different concentrations of chitosan decorated carbon nanotubes to acrylamide-co-acrylic acid hydrogels. The nanocomposites chemical structure was characterized by Fourier Transform Infrared Spectroscopy (FT-IR). The FT-IR shows the typical bands due to the hydrogel and additionally the peaks at 1750 cm and 1450 cm that correspond to the carbon nanotubes incorporated into the polymer matrix. Mechanical properties and swelling measurements in different buffer solutions were also performed. The nanocomposites showed improved mechanical properties and a stronger pH-response. In order to evaluate antimicrobial activity, the growth and adhesion of Staphylococcus aureus to nanocomposites were studied. Cytocompatibility was also evaluated by MTT assay on MDCK and 3T3 cell lines. The nanocomposites were found to be cytocompatible and showed a reduced bacterial colonization.

The aim of this study was to perform a current molecular characterization of bovine pathogenic Escherichia coli strains isolated from random samplings in Argentinean dairy farms. Rectal swabs were obtained from 395 (63.7%) healthy and 225 (36.3%) diarrheic calves, belonging to 45 dairy farms in Cordoba Province, Argentina. E. coli isolates were examined for virulence genes (f5, f41, f17, sta, stb, lt, eae, vt) using PCR and the prevalence of E. coli virulence profiles was spatially described in terms of spatial distribution. A total of 30.1% isolates were found to be positive for at least one of the virulence genes. Depending on the different gene combinations present, 11 virulence profiles were found. Most of the isolates analyzed had a single gene, and no combination of fimbrial and enterotoxin gene was predominant. There was no association between the frequency and distribution of E. coli virulence genes and calf health status. Most of the virulence profiles were compatible with ETEC strains and showed a homogeneous distribution over the sampled area. A clustering pattern for E. coli virulence profiles could not be recognized. This work provides updated information on the molecular characterization of pathogenic E. coli strains from dairy herds in Cordoba, Argentina. These findings would be important to formulate prevention programs and effective therapies for diarrhea in calves caused by E. coli.

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