Adding Sentence Types to a Model of Syntactic Category Acquisition

The acquisition of syntactic categories is a crucial step in the process of acquiring syntax. At this stage, before a full grammar is available, only surface cues are available to the learner. Previous computational models have demonstrated that local contexts are informative for syntactic categorization. However, local contexts are affected by sentence‐level structure. In this paper, we add sentence type as an observed feature to a model of syntactic category acquisition, based on experimental evidence showing that pre‐syntactic children are able to distinguish sentence type using prosody and other cues. The model, a Bayesian Hidden Markov Model, allows for adding sentence type in a few different ways; we find that sentence type can aid syntactic category acquisition if it is used to characterize the differences in word order between sentence types. In these models, knowledge of sentence type permits similar gains to those found by extending the local context.     

Effects of Pedunculopontine Area and Pallidal DBS on Gait Ignition in Parkinson's Disease

BackgroundFreezing of gait is a disabling feature of Parkinson's disease, and so far no established treatment exists. Deep brain stimulation of the pedunculopontine area has been proposed to treat refractory gait disorders, yet data on measurable effects, especially in combination with stimulation of other targets, are scarce.MethodsAcute effects of either low frequency pedunculopontine stimulation or high frequency stimulation of the posteroventral lateral globus pallidus internus and a combination of both in a 66-year-old man with advanced Parkinson's disease were assessed. Four weeks after the intervention, the gait was examined with patient blinded in each condition using computerized gait analysis.ResultsIsolated pedunculopontine or pallidal stimulation had a mild impact on gait ignition and freezing of gait, but combined stimulation had a marked effect.ConclusionsCombined multifocal stimulation may be a promising option for gait ignition and freezing of gait in advanced Parkinson's disease.     

Botulinum toxin type A treatment in neurogenetic syndromes

Purpose: To review the use of therapeutic botulinum toxin type A (BoNT-A) treatments in uncommon neurogenetic syndromes.

Method: A retrospective questionnaire and interview study of a selected case series to assess the efficacy and safety following initial BoNT-A treatment (50–400 units per subject) was conducted to determine the response of families to treatment. Twelve male and six female subjects with ages from 2–19 years were included. The reasons for treatments were based on both patient-related and caregiver-related objectives. Satisfaction with achievement of stated goals was assessed by follow-up interviews.

Results: Beneficial effects were reported in 56%, some effects in 22% and no to minimal effects in 22%. The duration of effect ranged from 10 days to 12 months with an average of 3.16 months. Ten families would repeat the injections as needed, four would not and four were not sure. Unanticipated effects of BoNT-A treatments were reported by some families. Adverse effects did not occur with the doses that were used.

Conclusions: The results suggest that obtaining family input may be useful when treating spasticity in unusual circumstances. The use of BTX-A in uncommon neurogenetic syndromes was supported by the majority of families interviewed.     

Alginate–lanthanide microspheres for MRI-guided embolotherapy

In cancer therapy, a promising treatment option to accomplish a high tumor-to-normal-tissue ratio is endovascular intervention with microsized particles, such as embolotherapy. In this study, alginate microspheres (ams) were prepared with the JetCutter technique, which is based on cutting a sodium alginate solution jet stream into small droplets of uniform size which are then cross-linked with different lanthanides or iron-III, resulting in microspheres of a predefined size which can be visualized by magnetic resonance imaging (MRI). The microspheres were investigated for their size and morphology (light microscopy and scanning electron microscopy analysis), cation content and MRI properties. The lanthanide-ams formulations, with a uniform size of 250 μm and a cation content between 0.72–0.94%, showed promising results for MR imaging. This was further demonstrated for Ho³⁺-cross-linked alginate microspheres (Ho³⁺-ams), the most potent microsphere formulation with respect to MR visualization, allowing single sphere detection and detailed microsphere distribution examination. Intravascular infusion of Ho³⁺-ams by catherization of ex vivo rabbit and porcine liver tissue and assessment of the procedure with MRI clearly showed accumulation and subsequently embolization of the targeted vessels, allowing accurate monitoring of the microsphere biodistribution throughout the tissue. Therefore, the different alginate–lanthanide microsphere formulations developed in this study show great potential for utilization as image-guided embolotherapy agents.     

Thermoresponsive Substrates used for the Expansion of Human Mesenchymal Stem Cells and the Preservation of Immunophenotype

The facile regeneration of undifferentiated human mesenchymal stem cells (hMSCs) from thermoresponsive surfaces facilitates the collection of stem cells avoiding the use of animal derived cell detachment agents commonly used in cell culture. This communication proposes a procedure to fabricate coatings from commercially available pNIPAm which is both affordable and a significant simplification on alternative approaches used elsewhere. Solvent casting was used to produce films in the micrometer range and successful cell adhesion and proliferation was highly dependent on the thickness of the coating produced with 1 μm thick coatings supporting cells to confluence. 3T3 cell sheets and hMSCs were successfully detached from the cast coatings upon temperature reduction. Furthermore, results indicate that the hMSCs remained undifferentiated as the surface receptor profile of hMSCs was not altered when cells were detached in this manner.     

Singleton–Merten syndrome: An autosomal dominant disorder with variable expression

In 1973, Singleton and Merten described two females with abnormal dentition, unique radiographic changes especially of the hands, and severe calcification and intimal weakening of the aortic arch and valve. Since then three additional cases with similar features have been reported and the diagnosis was suggested in another three individuals. We present an update of one case and the detailed clinical phenotype of six other cases with Singleton–Merten syndrome. The occurrence of the disorder in six members of two families and vertical male‐to‐male transmission indicate an autosomal dominant pattern of inheritance. Variability in phenotype, also within a single family, is significant. Core manifestations are marked aortic calcification, dental anomalies (delayed eruption and immature root formation of primarily the anterior permanent teeth, and early loss of permanent teeth due to short roots, acute root resorption, high caries, and aggressive alveolar bone loss), osteopenia and acro‐osteolysis, and to a lesser extend also glaucoma, psoriasis, muscle weakness, and joint laxity. Additional clinical characteristics described here include particular facial characteristics (high anterior hairline, broad forehead, smooth philtrum, thin upper vermillion) and abnormal joint and muscle ligaments. The cause and pathogenesis of this syndrome remain unknown. © 2013 Wiley Periodicals, Inc.     

Ageing and the small,non-coding RNA world

MicroRNAs, a class of small, non-coding RNAs, are now widely known for their importance in many aspects of biology. These small regulatory RNAs have critical functions in diverse biological events, including development and disease. Recent findings show that microRNAs are essential for lifespan determination in the model organisms, Caenorhabditis elegans and Drosophila, suggesting that microRNAs are also involved in the complex process of ageing. Further, short RNA fragments derived from longer parental RNAs, such as transfer RNA cleavage fragments, have now emerged as a novel class of regulatory RNAs that inhibit translation in response to stress. In addition, the RNA editing pathway is likely to act in the double-stranded RNA-mediated silencing machinery to suppress unfavorable RNA interference activity in the ageing process. These multiple, redundant layers in gene regulatory networks may make it possible to both stably and flexibly regulate genetic pathways in ensuring robustness of developmental and ageing processes.