RNA-seq reveals the pan-transcriptomic impact of attenuating the gliotoxin self-protection mechanism in Aspergillus fumigatus.

BACKGROUND: Aspergillus fumigatus produces a number of secondary metabolites, one of which, gliotoxin, has been shown to exhibit anti-fungal activity. Thus, A. fumigatus must be able to protect itself against gliotoxin. Indeed one of the genes in the gliotoxin biosynthetic gene cluster in A. fumigatus, gliT, is required for self-protection against the toxin- however the global self-protection mechanism deployed is unclear. RNA-seq was employed to identify genes differentially regulated upon exposure to gliotoxin in A. fumigatus wild-type and A. fumigatus ∆gliT, a strain that is hypersensitive to gliotoxin. RESULTS: Deletion of A. fumigatus gliT resulted in altered expression of 208 genes (log2 fold change of 1.5) when compared to A. fumigatus wild-type, of which 175 genes were up-regulated and 33 genes were down-regulated. Expression of 164 genes was differentially regulated (log2 fold change of 1.5) in A. fumigatus wild-type when exposed to gliotoxin, consisting of 101 genes with up-regulated expression and 63 genes with down-regulated expression. Interestingly, a much larger number of genes, 1700, were found to be differentially regulated (log2 fold change of 1.5) in A. fumigatus ∆gliT when challenged with gliotoxin. These consisted of 508 genes with up-regulated expression, and 1192 genes with down-regulated expression. Functional Catalogue (FunCat) classification of differentially regulated genes revealed an enrichment of genes involved in both primary metabolic functions and secondary metabolism. Specifically, genes involved in gliotoxin biosynthesis, helvolic acid biosynthesis, siderophore-iron transport genes and also nitrogen metabolism genes and ribosome biogenesis genes underwent altered expression. It was confirmed that gliotoxin biosynthesis is induced upon exposure to exogenous gliotoxin, production of unrelated secondary metabolites is attenuated in A. fumigatus ∆gliT, while quantitative proteomic analysis confirmed disrupted translation in A. fumigatus ∆gliT challenged with exogenous gliotoxin. CONCLUSIONS: This study presents the first global investigation of the transcriptional response to exogenous gliotoxin in A. fumigatus wild-type and the hyper-sensitive strain, ∆gliT. Our data highlight the global and extensive affects of exogenous gliotoxin on a sensitive strain devoid of a self-protection mechanism and infer that GliT functionality is required for the optimal biosynthesis of selected secondary metabolites in A. fumigatus

Optical Coherence Tomography Features of Active and Inactive Retinal Neovascularization in Proliferative Diabetic Retinopathy

PURPOSE: To describe spectral domain-optical coherence tomography features of retinal neovascularization in proliferative diabetic retinopathy and thus to identify novel signs of new vessel activity. METHODS: Retrospective, cross-sectional study. Data were collected over a 9-month period. Spectral domain optical coherence tomography scans were performed over areas of new vessel complexes (NVC) in both the disk and elsewhere, and were qualitatively graded by two masked observers. New vessel complexes activity was determined using clinical and angiographic criteria and correlated with spectral domain optical coherence tomography features. RESULTS: Forty-three eyes of 30 patients with proliferative diabetic retinopathy were included. Sixty-one NVC lesions (neovascularization of the disk—37.7%, neovascularization elsewhere—62.3%) were captured by spectral domain-optical coherence tomography and analyzed. Among them, 63.9% were classified as active and 36.1% as quiescent. Five distinctive features were identified as significantly different between active and quiescent NVC: the presence of vitreous hyperreflective dots in active NVC (P = 0.002) and the presence of epiretinal membrane (P = 0.04), inner retinal tissue contracture (P = 0.03), vitreous invasion (P = 0.02), and protrusion towards vitreous (P = 0.002) in quiescent NVC. CONCLUSION: In this exploratory study, the presence of vitreous hyperreflective dots, epiretinal membrane, inner retinal tissue contracture, vitreous invasion, and vitreous protrusion were identified as distinct signs of disease activity. Such parameters may be useful as a noninvasive imaging modality in eyes undergoing treatment for proliferative diabetic retinopathy

Low-energy electron scattering from methanol and ethanol

Measured and calculated differential cross sections for elastic (rotationally unresolved) electron scattering from two primary alcohols, methanol (CH3OH) and ethanol (C2H5OH), are reported. The measurements are obtained using the relative flow method with helium as the standard gas and a thin aperture as the collimating target gas source. The relative flow method is applied without the restriction imposed by the relative flow pressure conditions on helium and the unknown gas. The experimental data were taken at incident electron energies of 1, 2, 5, 10, 15, 20, 30, 50, and 100 eV and for scattering angles of 5°–130°. There are no previous reports of experimental electron scattering differential cross sections for CH3OH and C2H5OH in the literature. The calculated differential cross sections are obtained using two different implementations of the Schwinger multichannel method, one that takes all electrons into account and is adapted for parallel computers, and another that uses pseudopotentials and considers only the valence electrons. Comparison between theory and experiment shows that theory is able to describe low-energy electron scattering from these polyatomic targets quite well

Health Economic and Safety Considerations for Artificial Intelligence Applications in Diabetic Retinopathy Screening

Systematic screening for diabetic retinopathy (DR) has been widely recommended for early detection in patients with diabetes to address preventable vision loss. However, substantial manpower and financial resources are required to deploy opportunistic screening and transition to systematic DR screening programs. The advent of artificial intelligence (AI) technologies may improve access and reduce the financial burden for DR screening while maintaining comparable or enhanced clinical effectiveness. To deploy an AI-based DR screening program in a real-world setting, it is imperative that health economic assessment (HEA) and patient safety analyses are conducted to guide appropriate allocation of resources and design safe, reliable systems. Few studies published to date include these considerations when integrating AI-based solutions into DR screening programs. In this article, we provide an overview of the current state-of-the-art of AI technology (focusing on deep learning systems), followed by an appraisal of existing literature on the applications of AI in ophthalmology. We also discuss practical considerations that drive the development of a successful DR screening program, such as the implications of false-positive or false-negative results and image gradeability. Finally, we examine different plausible methods for HEA and safety analyses that can be used to assess concerns regarding AI-based screening

Assessment of retinal vascular calibres as a biomarker of disease activity in birdshot chorioretinopathy

Purpose Birdshot chorioretinopathy (BCR) is a potentially blinding ocular disorder involving the retinal vasculature and choroid without any systemic manifestations. The objective of the study was to describe vascular calibre changes in BCR and analyse the possibility of this optical biomarker for staging and monitoring disease activity in BCR. Methods This retrospective case–control study at a tertiary referral eye centre in the UK included 33 eyes from 21 patients with BCR and equal number of eyes from control subjects. Diagnosis of BCR was confirmed on fundus fluorescein and indocyanine green angiography. Vascular calibres were measured using validated semiautomated software. Results Patients with BCR had smaller retinal venular calibres central retinal venular equivalent (CRVE) than controls (211.3 versus 227.9 μm, p = 0.008). After adjusting for variables, the difference between the two groups for CRVE at baseline was statistically significant based on two different analysis methods. Central retinal venular equivalent (CRVE) was lower at the 6-month follow-up visit (206.2 versus 213.8 μm, p-value = 0.03), and arteriole-to-venule ratio was larger (0.74 versus 0.71, p = 0.04) in subjects with BCR. Arteriolar calibre (CRAE) remained the same. Conclusion This study provides novel insight into the pattern of vascular involvement in BCR. There was significant difference in the CRVE in patients with BCR. More studies are needed to correlate this data with visual function and treatment outcome and to validate the findings

Paracentral acute middle maculopathy after uneventful ocular surgery with local anaesthetic blocks

OBJECTIVE: To describe the role of local anaesthetic blocks as a potential cause of paracentral acute middle maculopathy (PAMM) after uneventful ocular surgery. METHODS: Retrospective, observational, international, multicentre case series. Nine cases of PAMM with associated visual loss following uneventful ocular surgery with local anaesthetic blocks were observed in a 9-year period (2011-2020). Demographic, ocular and systemic data, anaesthetic data and surgical details were collected. Visual acuity (VA), fundus photography, fluorescein angiography, optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images were reviewed. RESULTS: All nine cases were associated with decreased VA at 24 h postoperative check (ranging from hand movement to 20/200). A hyperreflective band within the middle retinal layers was observed in the structural OCT in the acute phase, evolving to thinning and atrophy of the inner retinal layers in sequential follow-up scans performed. Fluorescein angiography showed delayed perfusion in early arterial phase with normal perfusion in late venous phases. OCTA showed decreased perfusion in the deep capillary plexus. Visual recovery was variable between cases during follow-up (ranging from count fingers to 20/20). CONCLUSIONS: A combination of a vasoconstrictive effect of the anaesthetic agent, an intraocular pressure spike and a mechanical effect of the volume of anaesthetic injected may result in decreased retinal artery perfusion and be evidenced as PAMM in OCT scans. PAMM may present as a potential complication of local anaesthetic blocks in cases of unexpected visual loss after uneventful ocular surgery

Optimizing OCT acquisition parameters for assessments of vitreous haze for application in uveitis

Detection and evaluation of inflammatory activity in uveitis is essential to the management of the condition, and yet continues to be largely dependent on subjective clinical measures. Optical coherence tomography (OCT) measurement of vitreous activity is an alternative to clinical vitreous haze scoring and has passed a number of early validation studies. In this study we aimed to evaluate the impact of ‘operator factors’ on the variability of the technique as part of the validation process, and to help evaluate its suitability for ‘real world’ use. Vitreous haze index was calculated as a ratio between the reflectivity of the vitreous and of the outer retina in each scan. Different scanning conditions were tested and their effect on the measurement is reported. Our results show that the ‘quantitative imaging’ technique of OCT-measured vitreous activity had good reliability in normal subjects under a range of ‘real world’ conditions, such as when the operator changes the averaging value. The technique was however vulnerable to highly inaccurate focussing or abnormal downward displacement of the image. OCT-based quantification of vitreous activity is a promising alternative to current subjective clinical estimates, with sufficient ‘tolerance’ to be used in routine clinical practice as well as clinical trials

Political Self-characterization of U.S. Medical Students

BACKGROUND: There have been no prior studies of the political self-characterization of U.S. physicians-in-training, and little is known about physicians’ political leanings or the critical relationship between medical issues and political orientations of physicians and physicians-in-training. METHODS: All medical students in the class of 2003 at 16 nationally representative U.S. schools were eligible to complete three questionnaire administrations (at freshman orientation, entrance to wards, and senior year). RESULTS: Among these medical students, 5% self-characterized as politically very conservative, 21% conservative, 33% moderate, 31% liberal, and 9% as very liberal.” Being male, white, Protestant, intending to specialize in Surgery or anesthesiology/pathology/radiology, or currently or previously being married significantly (P ≤ .001) increased the likelihood that a student self-identified as very conservative or conservative. Disagreement or strong disagreement with the statements, “I’m glad I chose to become a physician” and “Access to care is a fundamental human right,” were also both associated with being very conservative or conservative. Being more liberal was reported by blacks and Hispanics; those intending to become ob-gyns, psychiatrists, and pediatric subspecialists; and atheists, Jews, and adherents of eastern religions. CONCLUSIONS: U.S. medical students are considerably more likely to be liberal than conservative and are more likely to be liberal than are other young U.S. adults. Future U.S. physicians may be more receptive to liberal messages than conservative ones, and their political orientation may profoundly affect their health system attitudes

COMPARING FUNDUS FLUORESCEIN ANGIOGRAPHY AND SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN THE EVALUATION OF DIABETIC MACULAR PERFUSION

PURPOSE: To compare fundus fluorescein angiography (FFA) and swept-source optical coherence tomography angiography (SS-OCTA) in the evaluation of macular perfusion in diabetic patients. METHODS: Forty-one eyes (21 diabetic patients) seen at Moorfields Eye Hospital (London) over a 1-month interval underwent color fundus photography, FFA, and SS-OCTA imaging of the capillary superficial plexus using 2 different protocols: 3 × 3 mm and 4.5 × 4.5 mm. Quantitative assessment (foveal avascular zone diameters and area), qualitative analysis (macroscopic and microscopic levels) and Early Treatment Diabetic Retinopathy Study diabetic macular ischemia grading were performed. Artifacts were recorded. Intraclass correlation coefficients and weighted kappa values were calculated. RESULTS: Mean (SD) foveal avascular zone area was 0.695 (0.52) mm on FFA, 0.627 (0.54) mm on SS-OCTA 3 × 3 and 0.701 (0.54) mm on SS-OCTA 4.5 × 4.5 protocol. Intraclass correlation coefficients showed good agreement between FFA and SS-OCTA for both vertical diameter and foveal avascular zone area measurements. The agreement between SS-OCTA 3 × 3 and 4.5 × 4.5 was good for all quantitative measurements. Weighted kappa for diabetic macular ischemia grading showed low to fair agreement between FFA and SS-OCTA, whereas the agreement was good between two different SS-OCTA protocols. CONCLUSION: Swept-source OCTA is a reproducible technique in the assessment of macular perfusion in diabetic patients with special regards to foveal avascular zone analysis. The agreement with FFA is limited especially for diabetic macular ischemia grading. Fundus fluorescein angiography is more sensitive in identifying microaneurysms

(Digital) tools as professional and generational identity badges in the Chinese creative industries

Animators, architects, designers, and others active in the Chinese creative industries are expert users of tools, both analog and digital. Performances of expert tool use (the wearing of professional identity badges) are strategic ways of signaling creativity understood as sets of skills and character traits essential for attracting work projects but also for professional identity formation. Analogue tools are generally associated with creative openness and fluidity whereas digital tools are discursively constructed as a technological other to the analogue. ‘Older’ creatives (born before 1980) tend to apply some of the media-inflected discourse around the balinghou generation (born 1980–1989) to their younger competitors, including an assumed affinity with digital media and technologies (the pinning on of a generational identity badge). Such generational assumptions can have the effect of reinforcing project hierarchies and denying expert users of digital tools their claims to creativity