Purpose The effects of image doubling on logarithmic progression chart visual acuity were investigated by simulating diplopia on a computer monitor. Methods Ten participants (6M, 4F) aged 21–28 years (mean 22.4 ± 2.3) were assessed viewing with their left eye while wearing their best correction. Stimuli were eight rows of five Sloan letters, from 0.4 to −0.3 logMAR (6/15 to 6/3) arranged in logarithmic progression format, generated on an HD monitor. Stimuli were generated with different magnitudes of doubling, different directions of doubling, and different intensity ratios between the ghost image and main images. Results When the ghost image had the same intensity as the main image, there was a significant effect of doubling magnitude on visual acuity, with the mean acuity being −0.11 logMAR (6/4.7) for no doubling. Acuity thresholds (logMAR) increased when doubling exceeded 1 min of arc, reaching a level of 0.12 logMAR (6/7.9) for doubling of 16 min of arc. There were no significant effects of orientation on acuity, nor were there significant orientation‐doubling magnitude interaction effects of visual acuity. Image doubling magnitude level affected visual acuity differently for different ghost image intensities, with the highest acuity elevation occurring when ghost and main images were equal or nearly equal. For faint ghost image intensities (10% and 20%) image doubling did not significantly affect visual acuity. Conclusions Image doubling will degrade visual acuity if doubling is greater than 1 min of arc, and ghost images are sufficiently intense. However, even with very obvious visually‐disturbing image doubling, visual acuity remains only slightly reduced.
Purpose: Acute and persistent inflammation plays an important role in the establishment and progression of the pancreatic ductal adenocarcinoma (PDAC). Modified macrophages, tumour associated macrophages (TAMs) are key contributors to the survival, growth, and metastatic behaviour of the PDAC cells, by interacting with them. Central to the role of inflammation and TAMs, lies the NLRP3 inflammasome. The crosstalk between PDAC cells and TAMs has been postulated to regulate the NLRP3 inflammasome activity and the subsequent associated inflammation in the tumour microenvironment, which, in turn affects the crosstalk and the survival, proliferation and metastatic potential of PDAC cells. This study investigated the effects of LPS-stimulated inflammation on cell proliferation, levels of pro-inflammatory cytokines and the NLRP3 inflammasome pathway in a co-culture model using PDAC cells and macrophages, in the with or without MCC950, a NLRP3 specific inhibitor.Methods: The effects of LPS-stimulated inflammation were tested on two PDAC cell lines (Panc 10.05 and SW 1990) co-cultured with RAW 264.7 macrophages. Cell proliferation was determined using the MTT assay. Levels of pro-inflammatory cytokines, IL-1β and TNF-α were determined by ELISA. Western blot analyses were used to examine the expression of NLRP3 in both PDAC cells and macrophages.Results: The crosstalk between PDAC cell lines and macrophages under LPS-stimulation led to pro-inflammatory microenvironment, as evidenced by high levels of secreted IL-1β and TNF-α. The crosstalk was also responsible for regulating the NLRP3 expression in both PDAC cells and macrophages as well as promoting PDAC cell proliferation. Inhibition of the NLRP3 inflammasome by MCC950, counteracted the effects of LPS-stimulation on the crosstalk. However, MCC950 differentially modified the viability of the metastatic vs primary PDAC cells lines. Conclusion: The stimulation by LPS increased PDAC cells viability by modulating the crosstalk between PDAC cells and RAW 264.7 macrophages (in a co-culture model) that results in the activation of NLRP inflammasome. The specific inhibition of NLRP inflammasome by MCC950 effectively counteracted the LPS-stimulated inflammation.
Purpose This article aims to illustrate the principles of bearing fixing, a new computer‐controlled procedure for subjective determination of astigmatism, and to compare it with conventional clinician‐controlled Jackson crossed‐cylinder refraction. Methods The principles and method for bearing fixing are described. Astigmatism was measured using bearing fixing and Jackson cross‐cylinder twice on 20 visually normal participants aged between 18 and 34 years. After final sphere adjustment, acuity measurements were made with each refraction estimate. Results Bearing fixing results could be obtained for all participants. Mean bearing fixing cylinder magnitude was slightly higher than Jackson cross‐cylinder measures of cylinder magnitude, by 0.05D. Using vector analysis to take into account cylinder power and axis, mean bearing fixing astigmatism was not significantly different from cross‐cylinder astigmatism, but did have higher test‐retest variability (p < 0.05). Acuity with bearing fixing and cross‐cylinder corrections did not significantly differ in average value or repeatability. Conclusions Bearing fixing is a feasible method for subjective determination of astigmatism, and there are a number of potential improvements to the method which could make it faster and more precise.
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