Perilesional edema in radiation necrosis reflects axonal degeneration

BACKGROUND: Recently, we characterized a Gamma Knife® radiation necrosis mouse model with various magnetic resonance imaging (MRI) protocols to identify biomarkers useful in differentiation from tumors. Though the irradiation was focal to one hemisphere, a contralateral injury was observed that appeared to be localized in the white matter only. Interestingly, this injury was identifiable in T2-weighted images, apparent diffusion coefficient (ADC), and magnetization transfer ratio (MTR) maps, but not on post-contrast T1-weighted images. This observation of edema independent of vascular changes is akin to the perilesional edema seen in clinical radiation necrosis. FINDINGS: The pathology underlying the observed white-matter MRI changes was explored by performing immunohistochemistry for healthy axons and myelin. The presence of both healthy axons and myelin was reduced in the contralateral white-matter lesion. CONCLUSIONS: Based on our immunohistochemical findings, the contralateral white-matter injury is most likely due to axonal degeneration

A Measurement of Parity-Violating Neutron Transmission in Xenon

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Distinguishing tumor admixed in a radiation necrosis (RN) background: 1H and 2H MR with a novel mouse brain-tumor/RN model

PURPOSE: Distinguishing radiation necrosis (RN) from recurrent tumor remains a vexing clinical problem with important health-care consequences for neuro-oncology patients. Here, mouse models of pure tumor, pure RN, and admixed RN/tumor are employed to evaluate hydrogen ( MATERIALS AND METHODS: A pipeline of common quantitative RESULTS: Differences in quantitative CONCLUSIONS: These findings, employing a pipeline of quantitativ

A feasibility study to evaluate early treatment response of brain metastases one week after stereotactic radiosurgery using perfusion weighted imaging

BACKGROUND: To explore if early perfusion-weighted magnetic resonance imaging (PWI) may be a promising imaging biomarker to predict local recurrence (LR) of brain metastases after stereotactic radiosurgery (SRS). METHODS: This is a prospective pilot study of adult brain metastasis patients who were treated with SRS and imaged with PWI before and 1 week later. Relative cerebral blood volume (rCBV) parameter maps were calculated by normalizing to the mean value of the contralateral white matter on PWI. Cox regression was conducted to explore factors associated with time to LR, with Bonferroni adjusted p\u3c0.0006 for multiple testing correction. LR rates were estimated with the Kaplan-Meier method and compared using the log-rank test. RESULTS: Twenty-three patients were enrolled from 2013 through 2016, with 22 evaluable lesions from 16 patients. After a median follow-up of 13.1 months (range: 3.0-53.7), 5 lesions (21%) developed LR after a median of 3.4 months (range: 2.3-5.7). On univariable analysis, larger tumor volume (HR 1.48, 95% CI 1.02-2.15, p = 0.04), lower SRS dose (HR 0.45, 95% CI 0.21-0.97, p = 0.04), and higher rCBV at week 1 (HR 1.07, 95% CI 1.003-1.14, p = 0.04) had borderline association with shorter time to LR. Tumors \u3e2.0cm3 had significantly higher LR than if ≤2.0cm3: 54% vs 0% at 1 year, respectively, p = 0.008. A future study to confirm the association of early PWI and LR of the high-risk cohort of lesions \u3e2.0cm3 is estimated to require 258 patients. CONCLUSIONS: PWI at week 1 after SRS may have borderline association with LR. Tumors \u3c2.0cm3 have low risk of LR after SRS and may be low-yield for predictive biomarker studies. Information regarding sample size and potential challenges for future imaging biomarker studies may be gleaned from this pilot study

Neutron cross sections for He-3 at epithermal energies

High accuracy, absolute measurements of the neutron total cross section for He-3 are reported for incident neutron energies 0.1-400 eV. The measurements were performed at the LANSCE short-pulse neutron spallation source. Using the previously determined cross section for neutron elastic scattering, 3.367+/-0.019 b, we extract a new value for the energy dependence of the He-3(n,p)He-3 reaction cross section, sigma(np)=(849.77+/-0.14+/-1.02)E-1/2-(1.253+/-0.00+/-(+0.008)(-0.049))b, where the neutron energy is expressed in eV. The first uncertainty is statistical, the second systematic

Observation of a large parity nonconserving analyzing power in Xe

A large parity nonconserving longitudinal analyzing power was discovered in polarized-neutron transmission through Xe. An analyzing power of 4.3±0.2% was observed in a p-wave resonance at En=3.2 eV. The measurement was performed with a liquid Xe target of natural isotopic abundance that was placed in the polarized epithermal neutron beam, flight path 2, at the Manuel Lujan Neutron Science Center. This apparatus was constructed by the TRIPLE Collaboration, and has been used for studies of parity symmetry in compound nuclear resonances. Part of the motivation of the experiment was to discover a nucleus appropriate for a sensitive test of time-reversal invariance in polarized-neutron transmission. The large analyzing power of the observed resonance may make it possible to design a test of time reversal invariance using a polarized-Xe target

An international survey of speciality training in oral and maxillofacial pathology

BACKGROUND: Speciality training in oral and maxillofacial pathology (OMFP) across the world would be aided by guidance on a generic curriculum and training programme that all countries could use as a template. In order to facilitate this, we require an understanding of the various forms which OMFP training takes across the world. METHODS: We sent a questionnaire to OMF pathologists in the 42 countries represented in the IAOP membership, via their Regional Councillor. The questionnaire included detailed demographics, entry requirements, specialty training program and facilities/ resources. RESULTS: Replies were received from 22/42 countries (52%). OMFP is a dental/dental and medical speciality in 72%, and in 92% of those, this is recognised by a licensing board. Training was undertaken in an academic environment in 85% (with many offering a further academic qualification) and the median length of training was 4 years. General/anatomical pathology training is mandated in 85% of programs and a common core of general sub-specialities was identified. An end of training assessment was conducted in 80% of programs with most including written, practical and oral elements. Training program directors and educational supervisors were in place in 12/16 programs and, in most, Quality Assurance of training was externally monitored. In only one country was the number of trainees linked to workforce planning. CONCLUSIONS: Training in OMFP varies across the world. However, we feel there is sufficient commonality for the development of an agreed indicative framework on education and training in Oral and Maxillofacial Pathology, perhaps under the auspices of the IAOP.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1600-0714hb201