Assessment of smear layer removal protocols in curved root canals

This study sought to assess if the final rinse protocol interferes with the smear layer removal in the apical area of curved canals. Sixty‐four extracted human mandibular molars with curved mesial roots were instrumented with rotary files and divided into six experimental groups for final rinse: 1EDTA (syringe irrigation with 1 mL of 17% ethylenediaminetetraacetic acid (EDTA) ), 5EDTA (syringe irrigation with 5 mL of 17% EDTA), 1EDTA‐P (syringe irrigation with 1 mL of 17% EDTA + pumping with gutta‐percha point), 5EDTA‐P (syringe irrigation with 5 mL of 17% EDTA + pumping with gutta‐percha point), 1EDTA‐EA (syringe irrigation with 1 mL of 17% EDTA + EndoActivator) and 5EDTA‐EA (syringe irrigation with 5 mL of 17% EDTA + EndoActivator). Final rinsing was carried out over 3 min. The specimens were split lengthwise and observed under a scanning electron microscope using a score criterion. Comparison among the groups showed statistically significant difference only between the 5EDTA‐EA group and the other groups (Kruskal–Wallis and Dunn's post‐hoc tests, P < 0.05). The combination of 5 mL of 17% EDTA and 3 mL of 2.5% sodium hypochlorite (NaOCl) with the EndoActivator removed smear layer from the apical area of curved root canals more effectively than the other protocols used.     

Comparison of the verification performance and radiation dose between ExacTrac x-ray system and On-Board Imager—A phantom study

Recently, On-Board Imager (OBI) and ExacTrac x-ray 6 degree-of-freedom system (ExacTrac) are increasingly used verification systems in local radiotherapy centers. This study aimed to compare the differences between these two systems in terms of verification accuracy, organ doses, and verification time for head-and-neck (H&N) and pelvic cases. Rando anthropomorphic phantoms of H&N and pelvic regions were positioned with known set-up deviations from the reference position in the linear accelerator. x-Ray verification images were then acquired using both systems. Verification accuracy was evaluated based on the residual positioning error (δD) after image registration. Thermoluminescence dose meters (TLD-100s) were placed in specific locations of the phantoms for the measurement of imaging doses at the organs of interest. Besides, the verification time was also recorded for comparison. Most average detection errors for both systems were within 1?mm. The detection error of ExacTrac was significantly larger than OBI in the H&N region in all directions (p?<?0.05), but was significantly lower in the pelvis (p?<?0.05). The mean imaging doses to all organs of interest from ExacTrac were significantly lower than OBI (p?<?0.05). The mean verification time for ExacTrac was about 10 seconds, which was significantly shorter than the 100 seconds in OBI (p?<?0.001). Both verification systems achieved satisfactory performance in the H&N and pelvic regions despite ExacTrac being better in terms of verification time and organ dose. The verification accuracy of Exactrac was better in pelvic region than the H&N region when compared with OBI.     

Increased expression of tumor-associated antigens in pediatric and adult ependymomas: implication for vaccine therapy

Despite surgery and radiotherapy, as many as 50 % of children with ependymomas will suffer from tumor recurrences that will ultimately lead to death. Our group’s initial peptide-based glioma vaccine targeting EphA2, IL-13Rα2, and Survivin, which are overexpressed in pediatric gliomas, has shown promise in its initial phase of testing. We therefore investigated whether EphA2, IL-13Rα2, Survivin, and, additionally, Wilms’ Tumor 1 (WT1), are overexpressed in pediatric ependymomas to determine if a similar immunotherapy approach could be applicable. Immunohistochemistry was performed using antibodies specific for EphA2, IL-13Rα2, Survivin, and WT1 on paraffin-embedded specimens from 19 pediatric and 13 adult ependymomas. Normal brain and ependyma were used for background staining controls. Negative staining was defined as no staining or staining equaling the background intensity in normal brain tissues. In the 19 pediatric cases, 18 (95 %) demonstrated positive staining for EphA2, 16 (84 %) for IL-13Rα2, 18 (95 %) for Survivin, and only 7 (37 %) for WT1. Only 3 of 19 cases were positive for two or fewer tumor-associated antigens (TAAs); 16 of 19 cases were positive for three or more TAAs. In the 13 adult cases, all 13 demonstrated positive staining for EphA2, IL-13Rα2, and Survivin. Only 2 of 13 cases (15 %) demonstrated positive staining for WT1. All adult specimens were positive for three or more TAAs. Some ependymomas showed patchy variability in intensity. Pediatric and adult ependymomas frequently express EphA2, IL-13Rα2, and Survivin. This provides the basis for the utilization of an established multiple peptide vaccine for ependymoma in a clinical trial setting.     

Polygon-based image registration: a new approach for geo-referencing historical maps

This paper presents a new approach for geo-referencing historical maps using a polygon-based image registration technique. Since most historical maps lack long lasting point features to serve as control primitives for image registration, we explore the use of polygon features as control primitives that can be identified in both the map and the geo-referenced coordinate system based on matching the polygons’ shape context. A coordinate transformation model can be established using the matched vertices of the polygons, and the model coefficients are subsequently estimated using least-squares adjustment. The proposed method was tested on a digitized lithographic map of downtown Toronto, Ontario, Canada, created in 1857. The experimental work showed a good agreement for the image registration where the Dice similarity coefficient was 0.8 (i.e. 80% of overlap found between the two sets of polygons), regardless of using affine or polynomial model.     

Idiopathic blepharospasm does not lead to a parkinsonian syndrome: results of a questionnaire-based follow-up study

It has been suggested that a lesion in the dopaminergic neurons of the substantia nigra pars compacta combined with eye irritation is involved in the pathophysiology of idiopathic blepharospasm. If so, these patients might be prone to develop Parkinson’s disease or a parkinsonian syndrome. We therefore conducted a validated questionnaire-based follow-up study to estimate (a) the frequency of local eye disorders at onset and (b) frequency of development of parkinsonian symptoms in blepharospasm patients. Ninety-nine patients previously diagnosed with idiopathic blepharospasm were sent a two-part questionnaire to assess parkinsonian and other symptoms associated with their condition. The average period of follow-up was 12.7 years, ranging from 3 to 26 years, with an average age at onset of 53.5 years. Sixty-two patients reported other ocular symptoms prior to or at the onset of blepharospasm, and therefore ocular disease may act as a trigger to produce blepharospasm in those already predisposed. Only two patients had developed a score on the parkinsonism rating scale indicating possible Parkinson’s disease, but clinical examination confirmed this not to be the case. If a lesion in the dopaminergic neurons is involved in blepharospasm, it would appear to be relatively minor (and non-progressive), since patients with idiopathic blepharospasm do not seem prone to develop parkinsonian symptoms. Received: 14 April 1998 Received in revised form: 15 July 1998 Accepted: 4 August 1998