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Resumen Introducción y objetivo: El apiñamiento se ha convertido en una de las primeras causas de morbilidad y de consulta en la odontología pediátrica, por esto el tratamiento temprano ha sido propuesto como una alternativa para interceptarlo, y así evitar que empeoren o se extiendan a la dentición permanente. Las Pistas Planas Directas (PPD) son aparatos de acción bimaxilar que están encaminadas a la rehabilitación neurooclusal en edades tempranas, con la finalidad de rehabilitar el movimiento lateral de la mandíbula y magnificar la alternancia en la función masticatoria. El objetivo de esta investigación fue evaluar los cambios dentoalveolares que ocurren en el plano transversal con el uso de PPD en pacientes clase I con apiñamiento anterior, entre los 4-5 años de edad con dentición decidua. Materiales y métodos: La muestra constó de 6 sujetos a los cuales se les realizaron modelos iníciales, montaje en gnatostato, elaboración y cementación de PPD y modelos 6 y 12 meses después, para observar diferencias. Resultados: Se encontraron diferencias estadísticamente significativas en la distancia intercanina maxilar, en la distancia intermolar maxilar y en el espacio requerido maxilar derecho, entre el modelo inicial, los 6 y 12 meses de instalada la terapéutica. Conclusión: Pacientes tratados tempranamente con PPD presentan mayor desarrollo transversal y disminución en el apiñamiento, cuando son comparados con estudios longitudinales en pacientes sin tratamiento.

Abstract Introduction and objective: Crowding has become one of the leading causes of morbidity and consultation in pediatric dentistry, early treatment has been proposed as the best alternative to intercept malocclusions, preventing these from getting worse or perpetuate to the permanent dentition. Planas Direct Tracks (PPD) are devices with bimaxillary action aimed at neurooclusal rehabilitation at an early age, in order to rehabilitate the laterals movements of the jaw and enhace the masticatory function alternation. The objective of this study is to evaluate the dentoalveolar changes occurring in the transverse plane using PPD in patients Class I with anterior crowding between 4-5 years old. Materials and methods: The sample consisted of 6 subjects were models were performed before mounting them in the gnatostato, preparation and cementation of PPD and models six and twelve months later, to observe differences. Results: Statistically significant differences were found in the maxillary intercanine width, in maxillary intermolar distance and right space required maxillary, between the initial model and after 6 and 12 months of installed the therapy. Conclusion: Patients treated early with PPD have higher transverse development and decreased crowding, when compared with longitudinal studies in untreated patients.

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Typical assays used to discover and analyze small molecules that inhibit the hepatitis C virus (HCV) NS3 helicase yield few hits and are often confounded by compound interference. Oligonucleotide binding assays are examined here as an alternative. After comparing fluorescence polarization (FP), homogeneous time-resolved fluorescence (HTRF®; Cisbio) and AlphaScreen® (Perkin Elmer) assays, an FP-based assay was chosen to screen Sigma's Library of Pharmacologically Active Compounds (LOPAC) for compounds that inhibit NS3-DNA complex formation. Four LOPAC compounds inhibited the FP-based assay: aurintricarboxylic acid (ATA) (IC50=1.4 µM), suramin sodium salt (IC50=3.6 µM), NF 023 hydrate (IC50=6.2 µM) and tyrphostin AG 538 (IC50=3.6 µM). All but AG 538 inhibited helicase-catalyzed strand separation, and all but NF 023 inhibited replication of subgenomic HCV replicons. A counterscreen using Escherichia coli single-stranded DNA binding protein (SSB) revealed that none of the new HCV helicase inhibitors were specific for NS3h. However, when the SSB-based assay was used to analyze derivatives of another non-specific helicase inhibitor, the main component of the dye primuline, it revealed that some primuline derivatives (e.g. PubChem CID50930730) are up to 30-fold more specific for HCV NS3h than similarly potent HCV helicase inhibitors.

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This chapter describes two types of FRET-based fluorescence assays that can be used to identify and analyze compounds that inhibit the helicase encoded by the hepatitis C virus (HCV). Both assays use a fluorescently labeled DNA or RNA oligonucleotide to monitor helicase-catalyzed strand separation, and they differ from other real-time helicase assays in that they do not require the presence of other nucleic acids to trap the reaction products. The first assay is a molecular beacon-based helicase assay (MBHA) that monitors helicase-catalyzed displacement of a hairpin-forming oligonucleotide with a fluorescent moiety on one end and a quencher on the other. DNA-based MBHAs have been used extensively for high-throughput screening (HTS), but RNA-based MBHAs are typically less useful because of poor signal to background ratios. In the second assay discussed, the fluorophore and quencher are split between two hairpin-forming oligonucleotides annealed in tandem to a third oligonucleotide. This split beacon helicase assay can be used for HTS with either DNA or RNA oligonucleotides. These assays should be useful to the many labs searching for HCV helicase inhibitors in order to develop new HCV therapies that are still desperately needed.

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