52 research outputs found
Microscopic Inner Retinal Hyper-reflective Phenotypes in Retinal and Neurologic Disease
Purpose.
We surveyed inner retinal microscopic features in retinal and neurologic disease using a reflectance confocal adaptive optics scanning light ophthalmoscope (AOSLO).
Methods.
Inner retinal images from 101 subjects affected by one of 38 retinal or neurologic conditions and 11 subjects with no known eye disease were examined for the presence of hyper-reflective features other than vasculature, retinal nerve fiber layer, and foveal pit reflex. The hyper-reflective features in the AOSLO images were grouped based on size, location, and subjective texture. Clinical imaging, including optical coherence tomography (OCT), scanning laser ophthalmoscopy, and fundus photography was analyzed for comparison.
Results.
Seven categories of hyper-reflective inner retinal structures were identified, namely punctate reflectivity, nummular (disc-shaped) reflectivity, granular membrane, waxy membrane, vessel-associated membrane, microcysts, and striate reflectivity. Punctate and nummular reflectivity also was found commonly in normal volunteers, but the features in the remaining five categories were found only in subjects with retinal or neurologic disease. Some of the features were found to change substantially between follow up imaging months apart.
Conclusions.
Confocal reflectance AOSLO imaging revealed a diverse spectrum of normal and pathologic hyper-reflective inner and epiretinal features, some of which were previously unreported. Notably, these features were not disease-specific, suggesting that they might correspond to common mechanisms of degeneration or repair in pathologic states. Although prospective studies with larger and better characterized populations, along with imaging of more extensive retinal areas are needed, the hyper-reflective structures reported here could be used as disease biomarkers, provided their specificity is studied further
Optical Coherence Tomography Findings After Childhood Lensectomy
Purpose: To explore the impact of childhood lensectomy on posterior segment development. /
Methods: Cross-sectional observational study at children's eye clinics at a tertiary referral center in London, UK. We included 45 children age 4 to 16 years with healthy eyes and 38 who had undergone lensectomy. We acquired posterior segment optical coherence tomography scans of both eyes. We used parametric and nonparametric tests in SPSS24 for the comparison of parameters between groups and within individuals; a P value less than 0.05 was considered significant. The main outcome measures were foveal pit depth and subfoveal choroidal thickness (CT). Secondary outcomes were inner and outer ring CT and photoreceptor layer parameters, macular and peripapillary retinal nerve fiber layer thickness. /
Results: Foveal pit depth and subfoveal CT are significantly reduced in eyes that have undergone lensectomy compared with nonoperated eyes. Inner ring CT and outer ring CT are reduced. Foveal inner retinal layer thickness is increased. Mean inner retinal and outer nuclear layer thickness are not affected. /
Conclusions: Childhood lensectomy is associated with a reduction in developmental foveal pit deepening and lack of developmental thickening of the posterior choroid. Mechanical and optical disruption of foveal and subfoveal choroidal development may affect structural foveal development after childhood lensectomy
Assessing Retinal Structure In Complete Congenital Stationary Night Blindness and Oguchi Disease
Purpose To examine retinal structure and changes in photoreceptor intensity after dark adaptation in patients with complete congenital stationary night blindness and Oguchi disease. Design Prospective, observational case series. Methods We recruited 3 patients with complete congenital stationary night blindness caused by mutations in GRM6, 2 brothers with Oguchi disease caused by mutations in GRK1, and 1 normal control. Retinal thickness was measured from optical coherence tomography images. Integrity of the rod and cone mosaic was assessed using adaptive optics scanning light ophthalmoscopy. We imaged 5 of the patients after a period of dark adaptation and examined layer reflectivity on optical coherence tomography in a patient with Oguchi disease under light- and dark-adapted conditions. Results Retinal thickness was reduced in the parafoveal region in patients with GRM6 mutations as a result of decreased thickness of the inner retinal layers. All patients had normal photoreceptor density at all locations analyzed. On removal from dark adaptation, the intensity of the rods (but not cones) in the patients with Oguchi disease gradually and significantly increased. In 1 Oguchi disease patient, the outer segment layer contrast on optical coherence tomography was 4-fold higher under dark-adapted versus light-adapted conditions. Conclusions The selective thinning of the inner retinal layers in patients with GRM6 mutations suggests either reduced bipolar or ganglion cell numbers or altered synaptic structure in the inner retina. Our finding that rods, but not cones, change intensity after dark adaptation suggests that fundus changes in Oguchi disease are the result of changes within the rods as opposed to changes at a different retinal locus
Structural and Functional Characteristics of Color Vision Changes in Choroideremia
Color vision is considered a marker of cone function and its assessment in patients with retinal pathology is complementary to the assessments of spatial vision [best-corrected visual acuity (BCVA)] and contrast detection (perimetry). Rod-cone and chorioretinal dystrophies—such as choroideremia—typically cause alterations to color vision, making its assessment a potential outcome measure in clinical trials. However, clinical evaluation of color vision may be compromised by pathological changes to spatial vision and the visual field. The low vision Cambridge Color Test (lvCCT) was developed specifically to address these latter issues. We used the trivector version of the lvCCT to quantify color discrimination in a cohort of 53 patients with choroideremia. This test enables rapid and precise characterization of color discrimination along protan, deutan, and tritan axes more reliably than the historically preferred test for clinical trials, namely the Farnsworth Munsell 100 Hue test. The lvCCT demonstrates that color vision defects—particularly along the tritan axis—are seen early in choroideremia, and that this occurs independent of changes in visual acuity, pattern electroretinography and ellipsoid zone area on optical coherence tomography (OCT). We argue that the selective loss of tritan color discrimination can be explained by our current understanding of the machinery of color vision and the pathophysiology of choroideremia
Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography
PURPOSE: Using optical coherence tomography angiography (OCTA) to investigate the area with flow in the superficial retinal vessel network (SVRN) and choriocapillaris (CC) layer among male subjects with choroideremia (CHM), female carriers, and normal controls to identify vascular changes. PATIENTS AND METHODS: Images of SRVN and CC layer were acquired in 9 affected males, 5 female carriers, and 14 age- and gender-matched controls using the Angiovue software of the RTVue XR Avanti. RESULTS: The mean age was 33 years for affected male CHM patients (median 30 years), 46 years for female carriers (median 53 years), and 39 years for controls (median 38.5). Mean SRVN area±SD in subjects with CHM was 12.93±2.06 mm², in carrier subjects 15.36±0.60 mm², and in controls 15.30±1.35 mm² (P<0.01). The mean CC area±SD with flow was 6.97±5.26 mm² in CHM subjects, 21.65±0.17 mm² in carriers and 21.36±0.76 mm² in controls (P<0.01). SRVN and CC area with flow showed a negative correlation in CHM subjects with the age (r=−0.86; P<0.003 and r=−0.77; P<0.01, respectively). CC area with flow had a positive correlation with SRVN (r=0.83, P<0.001). Overall, visual acuity had a negative correlation with SRVN and CC area with flow (r=−0.67, P<0.001 and r=−0.57, P<0.002, respectively). CONCLUSIONS: This is the first study to highlight changes in the SRVN in CHM subjects. OCTA detected a reduced area with flow in both retinal and choroidal circulations, and may be a useful tool for monitoring natural history and disease progression in forthcoming clinical trials
Repeatability of Foveal Measurements Using Spectralis Optical Coherence Tomography Segmentation Software
PURPOSE: To investigate repeatability and reproducibility of thickness of eight individual retinal layers at axial and lateral foveal locations, as well as foveal width, measured from Spectralis spectral domain optical coherence tomography (SD-OCT) scans using newly available retinal layer segmentation software.
METHODS: High-resolution SD-OCT scans were acquired for 40 eyes of 40 young healthy volunteers. Two scans were obtained in a single visit for each participant. Using new Spectralis segmentation software, two investigators independently obtained thickness of each of eight individual retinal layers at 0°, 2° and 5° eccentricities nasal and temporal to foveal centre, as well as foveal width measurements. Bland-Altman Coefficient of Repeatability (CoR) was calculated for inter-investigator and inter-scan agreement of all retinal measurements. Spearman's ρ indicated correlation of manually located central retinal thickness (RT0) with automated minimum foveal thickness (MFT) measurements. In addition, we investigated nasal-temporal symmetry of individual retinal layer thickness within the foveal pit.
RESULTS: Inter-scan CoR values ranged from 3.1μm for axial retinal nerve fibre layer thickness to 15.0μm for the ganglion cell layer at 5° eccentricity. Mean foveal width was 2550μm ± 322μm with a CoR of 13μm for inter-investigator and 40μm for inter-scan agreement. Correlation of RT0 and MFT was very good (ρ = 0.97, P 0.05); however this symmetry could not be found at 5° eccentricity.
CONCLUSIONS: We demonstrate excellent repeatability and reproducibility of each of eight individual retinal layer thickness measurements within the fovea as well as foveal width using Spectralis SD-OCT segmentation software in a young, healthy cohort. Thickness of all individual retinal layers were symmetrical at 2°, but not at 5° eccentricity away from the fovea
High-intensity exercise to promote accelerated improvements in cardiorespiratory fitness (HI-PACE): study protocol for a randomized controlled trial
Background:
African Americans have a disproportionate prevalence and incidence of type 2 diabetes compared with Caucasians. Recent evidence indicates that low cardiorespiratory fitness (CRF) level, an independent risk factor for type 2 diabetes, is also more prevalent in African Americans than Caucasians. Numerous studies in Caucasian populations suggest that vigorous exercise intensity may promote greater improvements in CRF and other type 2 diabetes risk factors (e.g., reduction of glucose/insulin levels, pulse wave velocity, and body fat) than moderate intensity. However, current evidence comparing health benefits of different aerobic exercise intensities on type 2 diabetes risk factors in African Americans is negligible. This is clinically important as African Americans have a greater risk for type 2 diabetes and are less likely to meet public health recommendations for physical activity than Caucasians. The purpose of the HI-PACE (High-Intensity exercise to Promote Accelerated improvements in CardiorEspiratory fitness) study is to evaluate whether high-intensity aerobic exercise elicits greater improvements in CRF, insulin action, and arterial stiffness than moderate-intensity exercise in African Americans.
Methods/Design:
A randomized controlled trial will be performed on overweight and obese (body mass index of 25–45 kg/m2) African Americans (35–65 years) (n = 60). Participants will be randomly assigned to moderate-intensity (MOD-INT) or high-intensity (HIGH-INT) aerobic exercise training or a non-exercise control group (CON) for 24 weeks. Supervised exercise will be performed at a heart rate associated with 45–55% and 70–80% of VO2 max in the MOD-INT and HIGH-INT groups, respectively, for an exercise dose of 600 metabolic equivalents of task (MET)-minutes per week (consistent with public health recommendations). The primary outcome is change in CRF. Secondary outcomes include change in insulin sensitivity (measured via an intravenous glucose tolerance test), skeletal muscle mitochondrial oxidative capacity (via near-infrared spectroscopy), skeletal muscle measurements (i.e., citrate synthase, COX IV, GLUT-4, CPT-1, and PGC1-α), arterial stiffness (via carotid-femoral pulse wave velocity), body fat, C-reactive protein, and psychological outcomes (quality of life/exercise enjoyment).
Discussion:
The anticipated results of the HI-PACE study will provide vital information on the health effects of high-intensity exercise in African Americans. This study will advance health disparity research and has the potential to influence future public health guidelines for physical activity
Nawożenie azotem a plon i jakość browarna jęczmienia jarego odmiany prestige
The aim of this study was to precisely quantify the effect of different level and
time of nitrogen application on the field and malting quality of spring barley grain of
cultivar Prestige. Source of results was the field experiment carried out in 2003-2005. The
experiment was carried out with the split-plot method in 4 replications. 8 fertilization
combinations were tested (0; 20; 40; 40 (20 + 20); 60; 60 (40 + 20); 80; 80 (60 + 20) kg
N·ha-1). It was found that in soil of the good wheat complex at content Nmin. = 55-77
kg·ha-1 in layer 0-90 cm in spring high grain yields are obtained already at fertilization
40-60 kg N·ha-1. Considerably higher productivity of these rates is obtained when they
were divided into two parts – presowing and that applied at 23 BBCH stage. Raw material
of the malting cultivar (Prestige) collected under different conditions of weather (year
with average total precipitation and wet year) and fertilization (N rates from 20 to 80 kg
N·ha-1) is characterized by small variability of main qualitative index values of grain, malt
and wort and comprehensive Q index according to EBC.Celem badań było szczegółowe skwantyfikowanie wpływu zróżnicowanego
poziomu i terminu aplikacji azotu na plon i wartość browarną ziarna jęczmienia
jarego odmiany Prestige. Źródłem wyników był eksperyment polowy przeprowadzony
w latach 2003-2005. W doświadczeniu prowadzonym metodą split-plot, w 4 replikacjach, testowano 8 kombinacji nawozowych (0; 20; 40; 40 (20 + 20); 60; 60 (40 + 20); 80; 80
(60 + 20) kg N·ha-1). Stwierdzono, że na glebie kompleksu pszennego dobrego przy
zawartości Nmin. = 55-77 kg·ha-1 w warstwie 0-90 cm wiosną uzyskuje się wysokie plony
ziarna już przy nawożeniu 40-60 kg N·ha-1. Wyraźnie większą produkcyjność tych dawek
osiąga się w przypadku ich podziału na dwie części – przedsiewną oraz zastosowaną
w stadium 23 BBCH. Surowiec odmiany browarnej (Prestige) zebrany w różnych
warunkach przyrodniczych (rok o przeciętnej sumie opadów i rok wilgotny) i nawozowych
(dawki N od 20 do 80 kg N·ha-1) charakteryzuje się małym zróżnicowaniem
wartości głównych wskaźników jakościowych ziarna, słodu i brzeczki oraz kompleksowym
wskaźnikiem Q według EBC
Basics of dental procedures – cephalogram
Zdjęcie cefalometryczne (cephalometric radiograph) jest zewnątrzustnym zdjęciem diagnostycznym obrazującym część twarzową czaszki (tkanki kostne i miękkie), służącym do pomiarów tych struktur. Zdjęcia cefalometryczne są wykonywane w dwóch projekcjach: 1. projekcja boczna (cefalometr boczny profilowy, LL z ang. latero-lateral projection, – wykonywana częściej; 2. projekcja tylno-przednia (cefalometr tylno-przedni, PA, z ang. postero-anterior projection, – wskazana do wykonania w przypadku asymetrii twarzy. Jest to podstawowe standardowe badanie w ortodoncji służące do oceny struktur kostnych, zębowych oraz ich relacji względem tkanek miękkich. Zdjęcia cefalometryczne są wykonywane ze wskazań ortodontycznych w celu zaplanowania leczenia oraz jego długofalowego monitorowania. Analiza cefalometryczna służy do oceny wzrostu i rozwoju kości i uzębienia u dzieci wymagających leczenia ortodontycznego
Yield and quality of winter wheat (Triticum aestivum L.) in response to different systems of foliar fertilization
Foliar fertilizers are increasingly used in agricultural practice to maximize the yield potential of T. aestivum. Foliar fertilization can effectively reverse nutritional deficiencies (macronutrients), and it can be used as the main method for supplying plants with the required micronutrients. The objective of this study was to determine the effect of various systems of foliar micronutrient and macronutrient fertilization on the yield and quality of wheat grain. A field experiment was carried out in 2012-2015, in the Agricultural Experiment Station in Bałcyny, owned by the University of Warmia and Mazury in Olsztyn. The highest grain yield (10.16 Mg ha-1) of winter wheat was noted in the treatment where foliar fertilizers were supplied in 5 applications. It was higher by 230-430 to 660 kg ha-1 than in plots where foliar fertilizers were supplied in 2 applications. Intensified foliar fertilization increased nitrogen (54%) and potassium (12%) concentrations, but decreased the magnesium (10%) content of winter wheat straw. The concentrations of phosphorus (0.34 g kg-1 dry matter (DM)), potassium (0.23 g kg-1 DM), calcium (0.40 g kg-1 DM) and sulfur (0.05 g kg-1 DM) in winter wheat grain increased in response to intensified foliar fertilization. Foliar application of liquid macronutrient and micronutrient fertilizers increased micronutrient concentrations in winter wheat straw (copper, zinc, manganese, iron), but decreased the micronutrient content of grain (copper, zinc, iron). Intensified foliar fertilization significantly reduced total protein content (1.1 g kg-1 DM) and gluten content (0.9%) and deteriorated protein quality. The influence of different foliar fertilization systems on the falling number was determined by precipitation levels during the heading and ripening of winter wheat. The rheological properties of dough (development, stability and softness) improved each year in response to intensified foliar fertilization with macronutrients and micronutrients
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