Periacetabular osteotomy through the pararectus approach: technical feasibility and control of fragment mobility by a validated surgical navigation system in a cadaver experiment

PURPOSE The pararectus approach has been validated for managing acetabular fractures. We hypothesised it might be an alternative approach for performing periacetabular osteotomy (PAO). METHODS Using four cadaver specimens, we randomly performed PAO through either the pararectus or a modified Smith-Petersen (SP) approach. We assessed technical feasibility and safety. Furthermore, we controlled fragment mobility using a surgical navigation system and compared mobility between approaches. The navigation system's accuracy was tested by cross-examination with validated preoperative planning software. RESULTS The pararectus approach is technically feasible, allowing for adequate exposure, safe osteotomies and excellent control of structures at risk. Fragment mobility is equal to that achieved through the SP approach. Validation of these measurements yielded a mean difference of less <1 mm without statistical significance. CONCLUSION Experimental data suggests the pararectus approach might be an alternative approach for performing PAO. Clinical validation is necessary to confirm these promising preliminary results.

A variationist approach to the examination of insertion and deletion of /h/ in Kosraean English

I report on language variation in the unresearched variety of English emerging on Kosrae, Federated States of Micronesia. English is spoken as the inter-island lingua franca throughout Micronesia and has been the official language of FSM since gaining its independence in 1986, though still retaining close ties with the US through and economic “compact” agreement. I present here an analysis of a corpus of over 90 Kosraean English speakers, compiled during a three month fieldwork trip to the island in the Western Pacific. The 45 minute sociolinguistically sensitive recordings are drawn from a corpus of old and young, with varying levels of education and occupations, and off-island experiences. In the paper I analyse two variables. The first variable is the realisation of /h/, often subject to deletion in both L1 and L2 varieties of English. Such occurrences are commonly associated with Cockney English, but also found in Caribbean English and the postcolonial English of Australia. For example:  Male, 31: yeah I build their house their local huts and they pay me /h/ deletion is frequent in Kosraean English, but, perhaps expectedly, occurs slightly less among people with higher contact with American English, through having spent longer periods off island. The second feature under scrutiny is the variable epenthesis of [h] to provide a consonantal onset to vowel-initial syllables.  Male, 31: that guy is really hold now This practice is also found beyond Kosraean English. Previous studies find h-epenthesis arising in L1 varieties including Newfoundland and Tristan de Cunha English, while similar manifestations are identified in Francophone L2 learners of English. My variationist statistical analysis has shown [h] insertion:  to disproportionately occur intervocalically;  to be constrained by both speaker gender and age: older males are much more likely to epenthesis [h] in their speech;  to be more likely in the onset of stressed as opposed to unstressed syllables. In light of the findings of my analysis, I consider the relationship between h-deletion and h-epenthesis, the plausibility of hypercorrection as a motivation for the variation, and the potential influence of the substrate language, alongside sociolinguistic factors such as attitudes towards the US based on mobility. The analysis sheds light on the extent to which different varieties share this characteristic and the comparability of them in terms of linguistic constraints and attributes. Clarke, S. (2010). Newfoundland and Labrador English. Edinburgh: Edinburgh University Press Hackert, S. (2004). Urban Bahamian Creole: System and Variation. Varieties of English Around the World G32. Amsterdam: Benjamins Milroy, J. (1983). On the Sociolinguistic History of H-dropping in English in Current topics in English historical linguistics: Odense UP

Impact of Different Illumination Conditions on Visual Caries Detection with ICDAS

The aim of this study was to test the influence of different degrees of additional illumination on visual caries detection using the International Caries Detection and Assessment System (ICDAS). Two calibrated examiners assessed 139 occlusal surfaces of extracted permanent molars using a standard operation lamp with or without an additional headlamp providing three default brightness intensities. Histology served as the gold standard. Pooled data showed no differences in sensitivities. Specificities were not influenced by additional light. The area under the curve for the Marthaler classification D3 threshold was significantly lower when an additional strong headlamp was used (0.59 compared to 0.69-0.72 when reduced illumination intensities were used). One of the two examiners also had a significantly lower sensitivity for the D1 threshold when an additional headlamp was used. The use of additional white light led to a reduced detection of dentine lesions.

Thyroid disruption in zebrafish (Danio rerio) larvae: Different molecular response patterns lead to impaired eye development and visual functions

The vertebrate thyroid system is important for multiple developmental processes, including eye development. Thus, its environmentally induced disruption may impact important fitness-related parameters like visual capacities and behaviour. The present study investigated the relation between molecular effects of thyroid disruption and morphological and physiological changes of eye development in zebrafish (Danio rerio). Two test compounds representing different molecular modes of thyroid disruption were used: propylthiouracil (PTU), which is an enzyme-inhibitor of thyroid hormone synthesis, and tetrabromobisphenol A (TBBPA), which interacts with the thyroid hormone receptors. Both chemicals significantly altered transcript levels of thyroid system-related genes (TRα, TRβ, TPO, TSH, DIO1, DIO2 and DIO3) in a compound-specific way. Despite these different molecular response patterns, both treatments resulted in similar pathological alterations of the eyes such as reduced size, RPE cell diameter and pigmentation, which were concentration-dependent. The morphological changes translated into impaired visual performance of the larvae: the optokinetic response was significantly and concentration-dependently decreased in both treatments, together with a significant increase of light preference of PTU-treated larvae. In addition, swimming activity was impacted. This study provides first evidence that different modes of molecular action of the thyroid disruptors can be associated with uniform apical responses. Furthermore, this study is the first to show that pathological eye development, as it can be induced by exposure to thyroid disruptors, indeed translates into impaired visual capacities of zebrafish early life stages.

Fluorescence Lifetime Imaging in Stargardt Disease: Potential Marker for Disease Progression.

PURPOSE The purpose of this study was to describe autofluorescence lifetime characteristics in Stargardt disease (STGD) using fluorescence lifetime imaging ophthalmoscopy (FLIO) and to investigate potential prognostic markers for disease activity and progression. METHODS Fluorescence lifetime data of 16 patients with STGD (mean age, 40 years; range, 22-56 years) and 15 age-matched controls were acquired using a fluorescence lifetime imaging ophthalmoscope based on a Heidelberg Engineering Spectralis system. Autofluorescence was excited with a 473-nm laser, and decay times were measured in a short (498-560 nm) and long (560-720 nm) spectral channel. Clinical features, autofluorescence lifetimes and intensity, and corresponding optical coherence tomography images were analyzed. One-year follow-up examination was performed in eight STGD patients. Acquired data were correlated with in vitro measured decay times of all-trans retinal and N-retinylidene-N-retinylethanolamine. RESULTS Patients with STGD displayed characteristic autofluorescence lifetimes within yellow flecks (446 ps) compared with 297 ps in unaffected areas. In 15% of the STGD eyes, some flecks showed very short fluorescence lifetimes (242 ps). Atrophic areas were characterized by long lifetimes (474 ps), with some remaining areas of normal to short lifetimes (322 ps) toward the macular center. CONCLUSIONS Patients with recent disease onset showed flecks with very short autofluorescence lifetimes, which is possible evidence of accumulation of retinoids deriving from the visual cycle. During the study period, many of these flecks changed to longer lifetimes, possibly due to accumulation of lipofuscin. Therefore, FLIO might serve as a useful tool for monitoring of disease progression. (ClinicalTrials.gov number, NCT01981148.).