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Nordgren J.,Linkoping University | Bucardo F.,Linkoping University | Bucardo F.,National Autonomous University of Nicaragua, Leon | Svensson L.,Linkoping University | Lindgren P.-E.,Linkoping University
Journal of Clinical Microbiology | Year: 2010

We have developed a light-upon-extension (LUX) real-time PCR assay for detection, quantification, and genogrouping of group A rotavirus (RV), the most common cause of acute gastroenteritis in children. The LUX system uses a fluorophore attached to one primer and having a self-quenching hairpin structure, making it cost-effective and specific. We designed genogroup-specific primers having different fluorophores, making it possible to differentiate between the two main genogroups of human group A RVs. The assay was applied on clinical stool specimens from Sweden and Central America (n = 196) and compared to immunological and conventional PCR assays. The genogrouping ability was further validated against a subset of clinical specimens, which had been genogrouped using monoclonal antibodies. Our real-time PCR assay detected and quantified all positive specimens (n = 145) and exhibited higher sensitivity than immunological assays and conventional PCR. The assay exhibited a wide dynamic range, detecting from 5 to >107 genes per PCR, resulting in a theoretical lower detection limit of <10,000 viruses per gram of stool. No cross-reaction was observed with specimens containing norovirus, sapovirus, astrovirus, or adenovirus. In total, 22 (15%) of the positive clinical specimens were identified as genogroup I, 122 (84%) were identified as genogroup II, and 1 specimen was found to contain a mix of both genogroups. All genogroup I-positive specimens were associated with capsid glycoprotein 2 (G2). No significant difference in viral load was found between genogroups or geographic region. The detection and quantification, combined with the genogrouping ability, make this assay a valuable tool both for diagnostics and for molecular epidemiological investigations. Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Peguero G.,National Autonomous University of Nicaragua, Leon | Peguero G.,Autonomous University of Barcelona | Espelta J.M.,Autonomous University of Barcelona
Journal of Tropical Ecology | Year: 2011

Many plant species in tropical dry forests partly base their ability to persist after disturbance on resprouting. Yet little is known if this ability can be affected by the intensity and seasonality of disturbance and whether the amount of resources (starch, N, P) stored in the taproot may constrain this response. We investigated resprouting after experimental clipping or burning, applied before or after the dry season and repeatedly in Acacia pennatula individuals in wooded rangelands of North-West Nicaragua. Each treatment was applied to 12 trees and replicated in six plots. One year after the onset of the experiment, survival and biomass recovery were significantly lower in burned than in clipped individuals (78% ± 4% and 75.3 ± 8.0 g vs. 94% ± 2% and 79.1 ± 6.8 g; mean ± SE). Whatever the disturbance applied, trees disturbed after the dry season significantly showed the lowest survival, growth and concentration of N and P. These results suggest that resprouting in dry tropical species may be constrained by intense disturbances (e.g. burning) but especially if they occur towards the end of the dry season. This phenological constraint could be due to the reduced availability of N and P as this dry season progresses. © 2011 Cambridge University Press.

Bucardo F.,National Autonomous University of Nicaragua, Leon | Nordgren J.,Linkoping University
Infection, Genetics and Evolution | Year: 2015

Despite high rotavirus (RV) vaccine coverage (~83%) and good effectiveness (~77%) against RV-diarrhea hospitalization, RV is still contributing to the burden of diarrhea that persists in hospital settings in several Latin American countries, where RV vaccination is being implemented. Due to the extensive genomic and antigenic diversity, among co-circulating human RV, a major concern has been that the introduction of RV vaccination could exert selection pressure leading to higher prevalence of strains not included in the vaccines and/or emergence of new strains, thus, reducing the efficacy of vaccination. Here we review the molecular epidemiology of RV in Latin America and explore issues of RV evolution and selection in light of vaccination. We further explore etiologies behind the large burden of diarrhea remaining after vaccination in some countries and discuss plausible reasons for vaccine failures. © 2015 Elsevier B.V.

Romero-Gonzalez R.,University of Almeria | Garrido Frenich A.,University of Almeria | Martinez Vidal J.L.,University of Almeria | Prestes O.D.,Federal University of Santa Maria | Grio S.L.,National Autonomous University of Nicaragua, Leon
Journal of Chromatography A | Year: 2011

A method for the simultaneous determination of pesticides, biopesticides and mycotoxins from organic products was developed. Extraction of more than 90 compounds was evaluated and performed by using a modified QuEChERS-based (acronym of Quick, Easy, Cheap, Effective, Rugged, and Safe) sample preparation procedure. The method was based on a single extraction with acidified acetonitrile, followed by partitioning with salts, avoiding any clean-up step prior the determination by ultra-high performance liquid chromatography/tandem quadrupole mass spectrometry (UHPLC-MS/MS). Validation studies were carried out in wheat, cucumber and red wine as representative matrixes. Recoveries of the spiked samples were in the range between 70 and 120% (with intra-day precision, expressed as relative standard deviation, lower than 20%) for most of the analysed compounds, except picloram and quinmerac. Inter-day precision, expressed as relative standard deviation, was lower than 24%. Limits of quantification were lower than 10μgkg-1 and the developed method was successfully applied to the analysis of organic food products, detecting analytes belonging to the three types of compounds. © 2011 Elsevier B.V.

Luna D.V.,National Autonomous University of Nicaragua, Leon
International Journal of Gynecological Pathology | Year: 2010

Liesegang rings (LRs) are laminated precipitation structures well recognized in the field of chemistry. I present a rare case of a 53-year-old female who consulted for pelvic pain and abnormal uterine bleeding. The pelvic ultrasound revealed intramural and submucous uterine leiomyomas, and she underwent hysterectomy and bilateral salpingo-oophorectomy. Gross examination showed several paratubal cysts, which contained multiple eosinophilic concentrically spherical and oval structures of variable size compatible with LRs. In the female genital tract only 8 cases with LRs have been reported. This is the first documented case of LRs appearing in paratubal cysts. LRs formation should be taken into account during the histopathologic examination of paratubal cysts and not be misdiagnosed as a parasitic infection or foreign material within the female genital tract. © 2010 International Society of Gynecological Pathologists.

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