Dosimetric evaluation of Gammamed High Dose Rate intraluminal brachytherapy applicators

BackgroundA survey of the literature on intraluminal brachytherapy reveals that even for a given tumour site, the dose prescribed varies considerably from one centre to another for multiple reasons: the treatment intent, the association with external beam therapy or not, the dose rate, the technique used and the point of dose specification. There is no common language in the literature as to how doses should be recorded and reported.AimThe purpose of this study was to dosimetrically evaluate various intraluminal brachytherapy applicators for the Gammamed high dose rate afterloading system.Materials/MethodsDosimetric evaluation was carried out for 8mm, 10mm, 12mm and 14mm diameter intraluminal applicators available with the Gammamed high dose rate after-loading system. Treatment planning for these applicators was carried out with the Abacus treatment planning system for active source length and 8cm, 10cm and 12cm. All evaluations were carried out for a prescription dose of 5Gy at the reference point of 1cm from the source axis. Reference volume length (RVL), treated volume (TV) and hyperdose sleeve radius (HSR) were noted down from the isodose plans. Iterative, geometric and equal times optimization routines were carried out for all evaluations with step size of 0.5cm.ResultsThe isodose curves showed tapering pattern towards the distal and proximal regions. The reference volume lengths were larger than active source lengths for 8mm and 10mm diameter applicators. Reference volume lengths were smaller than active source lengths for 12mm and 14mm diameter applicators hyperdose sleeve radius decreases with increase in diameter of the applicator. For 14mm diameter applicators, the hyperdose sleeve radius was smaller than the radius of the reference isodose. Iterative optimization routine gave a better average in terms of reference volume length for all four diameter applicators.ConclusionsWe evaluated the dosimetric parameters for various intraluminal applicators available with the Gammamed high dose rate remote afterloading system. The values of RVL and HSR were within acceptable limits for the four applicators considered in this study

TREM2 Lipid Sensing Sustains the Microglial Response in an Alzheimer’s Disease Model

SummaryTriggering receptor expressed on myeloid cells 2 (TREM2) is a microglial surface receptor that triggers intracellular protein tyrosine phosphorylation. Recent genome-wide association studies have shown that a rare R47H mutation of TREM2 correlates with a substantial increase in the risk of developing Alzheimer’s disease (AD). To address the basis for this genetic association, we studied TREM2 deficiency in the 5XFAD mouse model of AD. We found that TREM2 deficiency and haploinsufficiency augment β-amyloid (Aβ) accumulation due to a dysfunctional response of microglia, which fail to cluster around Aβ plaques and become apoptotic. We further demonstrate that TREM2 senses a broad array of anionic and zwitterionic lipids known to associate with fibrillar Aβ in lipid membranes and to be exposed on the surface of damaged neurons. Remarkably, the R47H mutation impairs TREM2 detection of lipid ligands. Thus, TREM2 detects damage-associated lipid patterns associated with neurodegeneration, sustaining the microglial response to Aβ accumulation

The plant pathogen enzyme AldC is a long-chain aliphatic aldehyde dehydrogenase.

Aldehyde dehydrogenases are versatile enzymes that serve a range of biochemical functions. Although traditionally considered metabolic housekeeping enzymes because of their ability to detoxify reactive aldehydes, like those generated from lipid peroxidation damage, the contributions of these enzymes to other biological processes are widespread. For example, the plant pathoge