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Clinical Physiology and Functional... Sep 2023The pupillary light reflex (PLR) is a method for measuring dynamic responses within the autonomic nervous system, and would have potential value as a point-of-care test...
The pupillary light reflex (PLR) is a method for measuring dynamic responses within the autonomic nervous system, and would have potential value as a point-of-care test in a psychiatry clinic if reproducible results could be obtained in a short period of time. We collected PLR from adult community volunteers and depressed outpatients with the purpose of demonstrating (1) that valid data could be obtained >90% of the time from both the community volunteers and the patients, and (2) that reproducible results could be obtained with repeated measurement over short periods of time. Valid data were captured for 90.3% of 76 participants, allowing for two attempts of the PLR per participant. Success rates were similar for depressed patients and community volunteers. Eighteen of these 76 participants provided repeated paired measurements after 5 and 10 min of dark adaptation, producing high correlations for maximum constriction velocity (MCV) between assay 1 and 2 (Pearson's r = 0.71, p < 0.001), but there was a significant 8% increase in velocity for MCV between assay 1 and 2 (∆ = 0.34 ± 0.59 mm/s, p < 0.05). In contrast, PLR measurements were stable when tested in a separate cohort of 21 additional participants at 10 and 15 min of dark adaptation with an MCV Pearson's correlation of r = 0.84, p < 0.001, with a nonsignificant 1% difference between the two time points. These findings indicate an acceptable rate of collecting valid and reproducible PLR data when contrasting two measurements of PLR after 10 or 15 min of dark adaptation in depressed and suicidal patients.
Topics: Adult; Humans; Reflex, Pupillary; Reproducibility of Results; Light; Volunteers; Outpatients
PubMed: 37190935
DOI: 10.1111/cpf.12834 -
Experimental Biology and Medicine... 2024This research aims to investigate the potential of using intrinsic optical signal (IOS) optoretinography (ORG) to objectively detect dark adaptation (DA) abnormalities...
This research aims to investigate the potential of using intrinsic optical signal (IOS) optoretinography (ORG) to objectively detect dark adaptation (DA) abnormalities related to rod photoreceptor degeneration. Functional optical coherence tomography (OCT) was employed in both wild-type (WT) and retinal degeneration 10 (rd10) mice to conduct this assessment. Dynamic OCT measurements captured the changes in retinal thickness and reflectance from light-to-dark transition. Comparative analysis revealed significant IOS alterations within the outer retina. Specifically, a reduction in thickness from external limiting membrane (ELM) peak to retinal pigment epithelium (RPE) peak was observed (WT: 1.13 ± 0.69 µm, 30 min DA; rd10: 2.64 ± 0.86 µm, 30 min DA), as well as a decrease in the intensity of the inner segment ellipsoid zone (EZ) in 30 min DA compared to light adaptation (LA). The reduction of relative EZ intensity was notable in rd10 after 5 min DA and in WT after 15 min DA, with a distinguishable difference between rd10 and WT after 10 min DA. Furthermore, our findings indicated a significant decrease in the relative intensity of the hypo-reflective band between EZ and RPE in rd10 retinas during DA, which primarily corresponds to the outer segment (OS) region. In conclusion, the observed DA-IOS abnormalities, including changes in ELM-RPE thickness, EZ, and OS intensity, hold promise as differentiators between WT and rd10 mice before noticeable morphological abnormalities occur. These findings suggest the potential of this non-invasive imaging technique for the early detection of dysfunction in retinal photoreceptors.
Topics: Mice; Animals; Retinal Degeneration; Dark Adaptation; Retina; Retinal Pigment Epithelium; Retinal Rod Photoreceptor Cells
PubMed: 38463390
DOI: 10.3389/ebm.2024.10024 -
Proceedings. Biological Sciences Nov 2023Convergent evolution is widely regarded as a signature of adaptation. However, testing the adaptive consequences of convergent phenotypes is challenging, making it...
Convergent evolution is widely regarded as a signature of adaptation. However, testing the adaptive consequences of convergent phenotypes is challenging, making it difficult to exclude non-adaptive explanations for convergence. Here, we combined feather reflectance spectra and phenotypic trajectory analyses with visual and thermoregulatory modelling to test the adaptive significance of dark plumage in songbirds of the California Channel Islands. By evolving dark dorsal plumage, island birds are generally less conspicuous to visual-hunting raptors in the island environment than mainland birds. Dark dorsal plumage also reduces the energetic demands associated with maintaining homeothermy in the cool island climate. We also found an unexpected pattern of convergence, wherein the most divergent island populations evolved greater reflectance of near-infrared radiation. However, our heat flux models indicate that elevated near-infrared reflectance is not adaptive. Analysis of feather microstructure suggests that mainland-island differences are related to coloration of feather barbs and barbules rather than their structure. Our results indicate that adaptive and non-adaptive mechanisms interact to drive plumage evolution in this system. This study sheds light on the mechanisms driving the association between dark colour and wet, cold environments across the tree of life, especially in island birds.
Topics: Animals; Songbirds; Feathers; Phenotype; Body Temperature Regulation; Channel Islands; Pigmentation; Islands
PubMed: 37964520
DOI: 10.1098/rspb.2023.1914 -
Investigative Ophthalmology & Visual... Oct 2023To assess the progression in functional and structural measures over a five-year period in patients with retinal dystrophy caused by RLBP1 gene mutation.
PURPOSE
To assess the progression in functional and structural measures over a five-year period in patients with retinal dystrophy caused by RLBP1 gene mutation.
METHODS
This prospective, noninterventional study included patients with biallelic RLBP1 mutations from two clinical sites in Sweden and Canada. Key assessments included ocular examinations, visual functional measures (best-corrected visual acuity [BCVA], contrast sensitivity [CS], dark-adaptation [DA] kinetics up to six hours for two wavelengths [450 and 632 nm], Humphrey visual fields [HVF], full-field flicker electroretinograms), and structural ocular assessments.
RESULTS
Of the 45 patients enrolled, 38 completed the full five years of follow-up. At baseline, patients had BCVA ranging from -0.2 to 1.3 logMAR, poor CS, HVF defects, and prominent thinning in central foveal thickness. All patients had extremely prolonged DA rod recovery of approximately six hours at both wavelengths. The test-retest repeatability was high across all anatomic and functional endpoints. Cross-sectionally, poorer VA was associated with older age (right eye, correlation coefficient [CC]: 0.606; left eye, CC: -0.578; P < 0.001) and HVF MD values decreased with age (right eye, CC: -0.672, left eye, CC: -0.654; P < 0.001). However, no major changes in functional or structural measures were noted longitudinally over the five-year period.
CONCLUSIONS
This natural history study, which is the first study to monitor patients with RLBP1 RD for five years, showed that severely delayed DA sensitivity recovery, a characteristic feature of this disease, was observed in all patients across all age groups (17-69 years), making it a potentially suitable efficacy assessment for gene therapy treatment in this patient population.
Topics: Humans; Adolescent; Young Adult; Adult; Middle Aged; Aged; Prospective Studies; Visual Fields; Visual Acuity; Retinitis Pigmentosa; Retinal Dystrophies
PubMed: 37883093
DOI: 10.1167/iovs.64.13.42 -
Plant Biotechnology Journal May 2024Higher-order chromatin structure is critical for regulation of gene expression. In plants, light profoundly affects the morphogenesis of emerging seedlings as well as...
Higher-order chromatin structure is critical for regulation of gene expression. In plants, light profoundly affects the morphogenesis of emerging seedlings as well as global gene expression to ensure optimal adaptation to environmental conditions. However, the changes and functional significance of chromatin organization in response to light during seedling development are not well documented. We constructed Hi-C contact maps for the cotyledon, apical hook and hypocotyl of soybean subjected to dark and light conditions. The resulting high-resolution Hi-C contact maps identified chromosome territories, A/B compartments, A/B sub-compartments, TADs (Topologically Associated Domains) and chromatin loops in each organ. We observed increased chromatin compaction under light and we found that domains that switched from B sub-compartments in darkness to A sub-compartments under light contained genes that were activated during photomorphogenesis. At the local scale, we identified a group of TADs constructed by gene clusters consisting of different numbers of Small Auxin-Upregulated RNAs (SAURs), which exhibited strict co-expression in the hook and hypocotyl in response to light stimulation. In the hypocotyl, RNA polymerase II (RNAPII) regulated the transcription of a SAURs cluster under light via TAD condensation. Our results suggest that the 3D genome is involved in the regulation of light-related gene expression in a tissue-specific manner.
PubMed: 38762905
DOI: 10.1111/pbi.14372 -
Ophthalmology. Retina Apr 2024To describe and quantify the structural and functional consequences of retinal vasculopathy with cerebral leukoencephalopathy (RVCL) on the neurosensory retina.
OBJECTIVE
To describe and quantify the structural and functional consequences of retinal vasculopathy with cerebral leukoencephalopathy (RVCL) on the neurosensory retina.
DESIGN
Cross sectional descriptive study from December 2021 to December 2022.
PARTICIPANTS
Retinal vasculopathy with cerebral leukoencephalopathy patients (n = 9, 18 eyes) recruited from the RVCL Research Center at Washington University in St. Louis.
METHODS
Retinal vasculopathy with cerebral leukoencephalopathy patients underwent comprehensive ophthalmological evaluation including OCT, OCT angiography (OCTA), ultrawidefield fundus imaging, retinal autofluorescence, dark adaptation, electroretinography (ERG), Goldmann kinetic perimetry, and fluorescein angiography (FA).
MAIN OUTCOME MEASURES
Comprehensive characterization from various modalities including best-corrected visual acuity, central subfield thickness (μm) from OCT, foveal avascular zone (mm) from OCTA, dark adaptation rod intercept (seconds), cone response in ERG, and presence or absence of vascular abnormalities, leakage, neovascularization, and nonperfusion on FA.
RESULTS
A total of 18 eyes from 9 individuals were included in this study. The best-corrected visual acuity ranged from 20/15 to 20/70. The mean central subfield thickness from OCT was 275.8 μm (range, 217-488 μm). The mean foveal avascular zone (FAZ) from OCTA was 0.65 (range, 0.18-1.76) mm. On dark adaptometry, the mean time was 5.02 (range, 2.9-6.5) minutes, and 1 individual had impaired dark adaptation. Electroretinography demonstrated mild cone response impairment in 4 eyes. On FA, there was evidence of macular and peripheral capillary nonperfusion in 16 of 18 eyes and notable areas of vascular leakage and retinal edema in 5 of the 18 eyes.
CONCLUSIONS
This study illustrates the phenotypic spectrum of disease and may be clinically valuable for aiding diagnosis, monitoring disease progression, and further elucidating the pathophysiology of RVCL to aid in the development of therapies.
FINANCIAL DISCLOSURE(S)
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
Topics: Humans; Male; Female; Cross-Sectional Studies; Tomography, Optical Coherence; Adult; Fluorescein Angiography; Visual Acuity; Electroretinography; Middle Aged; Multimodal Imaging; Leukoencephalopathies; Visual Fields; Retinal Diseases; Retinal Vessels; Young Adult; Fundus Oculi; Adolescent
PubMed: 38752998
DOI: 10.1016/j.oret.2023.10.013 -
The Journal of Experimental Biology Sep 2023Gymnotiformes are nocturnal fishes inhabiting the root mats of floating plants. They use their electric organ discharge (EOD) to explore the environment and to...
Gymnotiformes are nocturnal fishes inhabiting the root mats of floating plants. They use their electric organ discharge (EOD) to explore the environment and to communicate. Here, we show and describe tonic and phasic sensory-electromotor responses to light distinct from indirect effects depending on the light-induced endogenous circadian rhythm. In the dark, principally during the night, inter-EOD interval histograms are bimodal: the main peak corresponds to the basal rate and a secondary peak corresponds to high-frequency bouts. Light causes a twofold tonic but opposing effect on the EOD histogram: (i) decreasing the main mode and (ii) blocking the high-frequency bouts and consequently increasing the main peak at the expense of removal of the secondary one. Additionally, light evokes phasic responses whose amplitude increases with intensity but whose slow time course and poor adaptation differentiate from the so-called novelty responses evoked by abrupt changes in sensory stimuli of other modalities. We confirmed that Gymnotus omarorum tends to escape from light, suggesting that these phasic responses are probably part of a global 'light-avoidance response'. We interpret the data within an ecological context. Fish rest under the shade of aquatic plants during the day and light spots due to the sun's relative movement alert the fish to hide in shady zones to avoid macroptic predators and facilitate tracking the movement of floating plant islands by wind and/or water currents.
Topics: Animals; Electric Organ; Gymnotiformes; Movement; Electric Fish
PubMed: 37408509
DOI: 10.1242/jeb.245489 -
MedRxiv : the Preprint Server For... Sep 2023While intermediate and late age-Related Macular Degeneration (AMD) have been widely investigated, rare studies were focused on the pathophysiologic mechanism of early...
PURPOSE
While intermediate and late age-Related Macular Degeneration (AMD) have been widely investigated, rare studies were focused on the pathophysiologic mechanism of early AMD. Delayed rod-mediated dark adaptation (RMDA) is the first functional biomarker for incident early AMD. The status of outer retinal bands on optical coherence tomography (OCT) may be potential imaging biomarkers and the purpose is to investigate the hypothesis that the integrity of interdigitation zone (IZ) may provide insight into the health of photoreceptors and retinal pigment epithelium (RPE) in early AMD.
METHODS
We establish the structure-function relationship between ellipsoid zone (EZ) integrity and RMDA, and IZ integrity and RMDA in a large-scale OCT dataset from eyes with normal aging (n=237), early AMD (n=138), and intermediate AMD (n=101) by utilizing a novel deep-learning-derived algorithm with manual correction when needed to segment the EZ and IZ on OCT B-scans (57,596 B-scans), and utilizing the AdaptDx device to measure RMDA.
RESULTS
Our data demonstrates that slower RMDA is associated with less preserved EZ (r = -0.334; p<0.001) and IZ area (r = -0.591; p<0.001), and decreased IZ thickness (r = -0.434; p<0.001). These associations are not apparent when considering normal eyes alone.
CONCLUSIONS
The association with IZ area and RMDA in large-scale data is biologically plausible because retinoid availability and transfer at the interface attributed to IZ is rate-limiting for RMDA. This study supports the hypothesis that the IZ integrity provides insight into the health of photoreceptors and RPE in early AMD and is a potential new imaging biomarker.
PubMed: 37745353
DOI: 10.1101/2023.09.10.23295309 -
Eye (London, England) Mar 2024Visual fields under mesopic and scotopic lighting are increasingly being used for macular functional assessment. This review evaluates its statistical significance and... (Review)
Review
Visual fields under mesopic and scotopic lighting are increasingly being used for macular functional assessment. This review evaluates its statistical significance and clinical relevance, and the optimal testing protocol for early/intermediate age-related macular degeneration (AMD). PubMed and Embase were searched from inception to 14/05/2022. All quality assessments were performed according to GRADE guidelines. The primary outcome was global mean sensitivity (MS), further meta-analysed by: AMD classification scheme, device, test pattern, mesopic/scotopic lighting, stimuli size/chromaticity, pupil dilation, testing radius (area), background luminance, adaptation time, AMD severity, reticular pseudodrusen presence, and follow-up visit. From 1489 studies screened, 42 observational study results contributed to the primary meta-analysis. Supported by moderate GRADE certainty of the evidence, global MS was significantly reduced across all devices under mesopic and scotopic lighting with large effect size (-0.9 [-1.04, -0.75] Hedge's g, P < 0.0001). The device (P < 0.01) and lighting (P < 0.05) used were the only modifiable factors affecting global MS, whereby the mesopic MP-1 and MAIA produced the largest effect sizes and exceeded test-retest variabilities. Global MS was significantly affected by AMD severity (intermediate versus early AMD; -0.58 [-0.88, -0.29] Hedge's g or -2.55 [3.62, -1.47] MAIA-dB) and at follow-up visit (versus baseline; -0.62 [-0.84, -0.41] Hedge's g or -1.61[-2.69, -0.54] MAIA-dB). Magnitudes of retinal sensitivity changes in early/intermediate AMD are clinically relevant for the MP-1 and MAIA devices under mesopic lighting within the central 10° radius. Other factors including pupil dilation and dark adaptation did not significantly affect global MS in early/intermediate AMD.
PubMed: 38499857
DOI: 10.1038/s41433-024-03033-0 -
Quintessence International (Berlin,... Feb 2024To compare marginal gap width and depth with different cementation systems, excess removal, and after polishing.
OBJECTIVES
To compare marginal gap width and depth with different cementation systems, excess removal, and after polishing.
METHOD AND MATERIALS
In total, 80 composite crowns were milled, divided into ten groups, and cemented on identical artificial teeth. Eight crowns per group were fixed with (i) zinc phosphate cement (ZnOPh), (ii) glass-ionomer cement (GIC), (iii) resin-reinforced glass-ionomer cement (GIC mod), (iv) dual-curing adhesive composite (Comp dual), or (v) dual-curing self-adhesive composite (Comp SE dual). Excess removal was performed with a scaler after brief light-cure (tack-cure), final light-cure, during rubber or gel phase or by wiping with foam pellet. Curing was completed in chemical, dark cure, or light-curing modus. The specimens were polished and stored in water (37°C). The margins were digitized using a 3D laser-scanning microscope (VK-X100 series, Keyence). The width and the depth of the marginal gap were measured at 10 points between the crown margin and the preparation margin.
RESULTS
The width after excess removal varied between 65.1 ± 15.7 µm (Comp dual, wipe, with polishing) and 208.6 ± 266.7 µm (Comp SE dual, dark cure, without polishing). The depth varied between 29.8 ± 22.2 µm (Comp dual, wipe, with polishing) and 89.5 ± 45.2 µm (Comp SE dual, dark cure, without polishing). The impact on gap width and depth was detected for fixation material, excess removal, and polishing.
CONCLUSION
The gap depth and width depend on the luting material and the mode of access removal. Polishing can improve the gap quality, especially for GIC and resin-based systems.
Topics: Humans; Resin Cements; Surface Properties; Dental Cements; Glass Ionomer Cements; Cementation; Crowns; Materials Testing; Composite Resins
PubMed: 38108419
DOI: 10.3290/j.qi.b4780239