Fundus Autofluorescence and RPE Lipofuscin in Age-Related Macular Degeneration

Genes that increase susceptibility to age-related macular degeneration (AMD) have been identified; however, since many individuals carrying these risk alleles do not develop disease, other contributors are involved. One additional factor, long implicated in the pathogenesis of AMD, is the lipofuscin of retinal pigment epithelium (RPE). The fluorophores that constitute RPE lipofuscin also serve as a source of autofluorescence (AF) that can be imaged by confocal laser ophthalmoscopy. The AF originating from lipofuscin is excited by the delivery of short wavelength (SW) light. A second autofluorescence is emitted from the melanin of RPE (and choroid) upon near-infrared (NIR-AF) excitation. SW-AF imaging is currently used in the clinical management of retinal disorders and the advantages of NIR-AF are increasingly recognized. Here we visit the damaging properties of RPE lipofuscin that could be significant when expressed on a background of genetic susceptibility. To advance interpretations of disease-related patterns of fundus AF in AMD, we also consider the photochemical and spectrophotometric features of the lipofuscin compounds responsible for generating the fluorescence emission

Quantifying Fundus Autofluorescence in Patients With Retinitis Pigmentosa

Purpose Using quantitative fundus autofluorescence (qAF), we analyzed short-wavelength autofluorescent (SW-AF) rings in RP. Methods: Short-wavelength autofluorescent images (486 nm excitation) of 40 patients with RP (69 eyes) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference. Mean qAF was measured in eight preset segments (qAF8) and in region of interest (ROI)-qAF (200–700 μm) within and external to the borders of the rings at superior, temporal, and inferior sites relative to the ring. For both groups, qAF in patients with RP was compared to age-similar and race/ethnicity-matched healthy eyes at equivalent retinal locations. Results: In 71% of eyes of RP patients, qAF8 acquired internal to the inner border of the ring, was within the 95% confidence interval (CI) for healthy eyes, while in the remaining RP eyes qAF8 was either higher or lower than the CI. Measured external to the ring, qAF8 values were within the CI in 47% of RP eyes with the other eyes being higher or lower. In 28% of sites measured by ROI-qAF within the SW-AF ring, values were above the 95% CI of healthy controls. Region of interest-qAF measured just external to the ring was within the CI of healthy eyes in 74% of locations. The average local elevation in qAF within the ring was approximately 15%. In SD-OCT scans, photoreceptor-attributable reflectivity bands were thinned within and external to the ring. Conclusions: Increased fluorophore production may be a factor in the formation of the SW-AF rings in RP

Risk for life-threatening arrhythmia in newly diagnosed peripartum cardiomyopathy with low ejection fraction: a German multi-centre analysis

Introduction Peripartum cardiomyopathy (PPCM) is a rare cardiomyopathy characterized by an acute reduction in left ventricular ejection fraction (LVEF). Sudden deaths during the course of PPCM are reported to be elevated, the underlying mechanisms remains unknown. The aim of the present multi-centre study was to evaluate the arrhythmia burden in a multi-centre approach in patients with PPCM using a wearable cardioverter/defibrillator (WCD). Methods and results Forty-nine patients from 16 German centres with newly diagnosed PPCM and LVEF <= 35% receiving a WCD were included in this retrospective analysis. Mean follow-up was 15 +/- 10 months. At diagnosis, mean age was 33 +/- 5 years, parity was 2.1 +/- 1.6, LVEF was 21 +/- 7%, NYHA functional class was 3.4 +/- 0.7. Mean wear time was 120 +/- 106 days, mean wear time per day was 21.4 +/- 3.3 h. Six (12%) patients presented eight ventricular tachyarrhythmias during WCD period: five episodes of VF, two sustained ventricular tachycardia (VT) and one non-sustained VT occurred. Conclusion This multicentre study underpins the elevated risk for ventricular tachyarrhythmias in patients with newly diagnosed PPCM and reduced LVEF. A WCD should be considered for 3-6 months in these patients to prevent sudden cardiac death from ventricular tachyarrhythmias

Quantitative Fundus Autofluorescence and Optical Coherence Tomography in ABCA4 Carriers

PURPOSE. To assess whether carriers of ABCA4 mutations have increased RPE lipofuscin levels based on quantitative fundus autofluorescence (qAF) and whether spectral-domain optical coherence tomography (SD-OCT) reveals structural abnormalities in this cohort. METHODS. Seventy-five individuals who are heterozygous for ABCA4 mutations (mean age, 47.3 years; range, 9-82 years) were recruited as family members of affected patients from 46 unrelated families. For comparison, 57 affected family members with biallelic ABCA4 mutations (mean age, 23.4 years; range, 6-67 years) and two noncarrier siblings were also enrolled. Autofluorescence images (308, 488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference. The gray levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density to yield qAF. Horizontal SD-OCT scans through the fovea were obtained and the thicknesses of the outer retinal layers were measured. RESULTS. In 60 of 65 carriers of ABCA4 mutations (age range, 9-60), qAF levels were within normal limits (95% confidence level) observed for healthy noncarrier subjects, while qAF levels of affected family members were significantly increased. Perifoveal fleck-like abnormalities were observed in fundus AF images in four carriers, and corresponding changes were detected in the outer retinal layers in SD-OCT scans. Thicknesses of the outer retinal layers were within the normal range. CONCLUSIONS. With few exceptions, individuals heterozygous for ABCA4 mutations and between the ages of 9 and 60 years do not present with elevated qAF. In a small number of carriers, perifoveal fleck-like changes were visible

Longer and better lives for patients with atrial fibrillation:the 9th AFNET/EHRA consensus conference

Aims: Recent trial data demonstrate beneficial effects of active rhythm management in patients with atrial fibrillation (AF) and support the concept that a low arrhythmia burden is associated with a low risk of AF-related complications. The aim of this document is to summarize the key outcomes of the 9th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA). Methods and results: Eighty-three international experts met in Münster for 2 days in September 2023. Key findings are as follows: (i) Active rhythm management should be part of the default initial treatment for all suitable patients with AF. (ii) Patients with device-detected AF have a low burden of AF and a low risk of stroke. Anticoagulation prevents some strokes and also increases major but non-lethal bleeding. (iii) More research is needed to improve stroke risk prediction in patients with AF, especially in those with a low AF burden. Biomolecules, genetics, and imaging can support this. (iv) The presence of AF should trigger systematic workup and comprehensive treatment of concomitant cardiovascular conditions. (v) Machine learning algorithms have been used to improve detection or likely development of AF. Cooperation between clinicians and data scientists is needed to leverage the potential of data science applications for patients with AF. Conclusions: Patients with AF and a low arrhythmia burden have a lower risk of stroke and other cardiovascular events than those with a high arrhythmia burden. Combining active rhythm control, anticoagulation, rate control, and therapy of concomitant cardiovascular conditions can improve the lives of patients with AF

Space-borne Bose-Einstein condensation for precision interferometry

Space offers virtually unlimited free-fall in gravity. Bose-Einstein condensation (BEC) enables ineffable low kinetic energies corresponding to pico- or even femtokelvins. The combination of both features makes atom interferometers with unprecedented sensitivity for inertial forces possible and opens a new era for quantum gas experiments. On January 23, 2017, we created Bose-Einstein condensates in space on the sounding rocket mission MAIUS-1 and conducted 110 experiments central to matter-wave interferometry. In particular, we have explored laser cooling and trapping in the presence of large accelerations as experienced during launch, and have studied the evolution, manipulation and interferometry employing Bragg scattering of BECs during the six-minute space flight. In this letter, we focus on the phase transition and the collective dynamics of BECs, whose impact is magnified by the extended free-fall time. Our experiments demonstrate a high reproducibility of the manipulation of BECs on the atom chip reflecting the exquisite control features and the robustness of our experiment. These properties are crucial to novel protocols for creating quantum matter with designed collective excitations at the lowest kinetic energy scales close to femtokelvins.Comment: 6 pages, 4 figure

Korrelationen zwischen Nah-Infrarot und kurzwelliger Autofluoreszenz und Spektral-Domänen optische Kohärenztomografie in Morbus Stargardt

Purpose: Short-wavelength (SW) fundus autofluorescence (AF) is considered to originate from lipofuscin in retinal pigment epithelium (RPE) and near- infrared (NIR) AF from melanin. In patients with recessive Stargardt disease (STGD1), we correlated SW-AF and NIR-AF with structural information obtained by spectral domain optical coherence tomography (SD-OCT). Methods: Twenty-four STGD1 patients (45 eyes; age 8 to 61 years) carrying confirmed disease- associated ABCA4 mutations were studied prospectively. SW-AF, NIR-AF and SD- OCT images were acquired. Results: Five phenotypes were identified according to features of the central lesion and extent of fundus change. Central zones of reduced NIR-AF were typically larger than areas of diminished SW-AF and reduced NIR-AF usually approximated areas of ellipsoid zone (EZ) loss identified by SD-OCT (group 1; r, 0.93, p<0.0001). In patients having a central lesion with overlapping parafoveal rings of increased NIR-AF and SW-AF (group 3), the extent of EZ loss was strongly correlated with the inner diameter of the NIR-AF ring (r, 0.89, p<0.0001) and the eccentricity of the outer border of the NIR-AF ring was greater than that of the SW-AF ring. Conclusions: Lesion areas were more completely delineated in NIR-AF images than with SW-AF. In most cases EZ loss was observed only at locations where NIR-AF was reduced or absent, indicating that RPE cell atrophy occurs in advance of photoreceptor cell degeneration. Since SW-AF was often increased within the central area of EZ disruption, degenerating photoreceptor cells may produce lipofuscin at accelerated levels. Consideration is given to mechanisms underlying hyper-NIR-AF in conjunction with increased SW-AF.Einleitung: Es wird davon ausgegangen, dass die kurzwellige Fundusautofluoreszenz (SW-AF) von Lipofuszin im retinalen Pigmentepithel (RPE) hervorgerufen wird und die Nahinfrarot-Fundusautofluoreszenz (NIR-AF) von Melanin. Bei Patienten mit Morbus Stargardt (STGD1) wurden SW-AF und NIR-AF mit durch optische Kohärenztomographie (SD-OCT) gewonnenen strukturellen Informationen korreliert. Methodik: Vierundzwanzig STGD1 Patienten (45 Augen; Alter: 8-61 Jahre) mit nachgewiesenen krankheits-assoziierten ABCA4 Mutationen wurden prospektiv untersucht. SW-AF, NIR-AF und SD-OCT Aufnahmen wurden generiert. Ergebnisse: Fünf Phänotypen wurden identifiziert basierend auf Charakteristika der zentralen Läsion und Ausdehnung der Fundusveränderungen. Zentrale Areale mit reduziertem NIR-AF Signal waren typischerweise größer als Areale mit reduziertem SW-AF Signal und das reduzierte NIR-AF Signal zeigte meistens Übereinstimmung mit Arealen in den SD-OCT Aufnahmen, in denen die ellipsoid zone (EZ) verloren gegangen war (Gruppe 1; r, 0.93, p<0.0001). Bei Patienten, die eine zentrale Läsion mit sich überlappenden parafovealen Ringen mit erhöhtem NIR-AF und SW-AF Signal haben (Gruppe 3), war der EZ Verlust stark korreliert mit dem inneren Durchmesser des NIR-AF Ringes (r, 0.89, p<0.0001) und der äußere Rand des NIR-AF Ringes lag weiter peripher als der äußere Rand des SW-AF Ringes. Schlussfolgerungen: Die Läsionsareale waren besser abgrenzbar in NIR-AF Aufnahmen als in SW-AF Aufnahmen. In den meisten Fällen zeigte sich ein EZ Verlust nur an Orten, wo NIR-AF vermindert oder erloschen war, was darauf hindeutet, dass es in der Pathogenese von STGD1 zuerst zur RPE Atrophie und dann zur Degeneration von Photorezeptoren kommt. Da innerhalb des zentralen Fundusareals mit EZ Verlust SW-AF häufig erhöht war, könnten degenerierende Photorezeptoren Lipofuszin beschleunigt produzieren. Es werden Mechanismen erörtert, die einem erhöhten NIR-AF Signal in Verbindung mit einem erhöhten SW-AF Signal zugrunde liegen könnten

За кадры. 1977. № 37 (2032)

Добро пожаловать на электроэнергетический факультет! / Н. Г. ВолковПриумножая традиции / Н. БанныхЭлектрические станции / И. Д. КутявинКибернетика электрических систем / Р. А. ВайнштейнЭлектрические системы / Н. БанныхТехника высоких напряжений / В. Я. УшаковЭлектроснабжение промышленных предприятий / М. А. МельниковМы - целине, целина - нам / Т. КуммерЗаботы профбюро / С. БалакинСильные, ловкие, смелые / Л. АзаренковаУсловия прием

Acute echocardiographic and electrocardiographic effects of triggered left ventricular pacing

Cardiac resynchronization therapy (CRT) is an essential pillar in the therapy of heart failure patients with reduced ejection fraction (HFrEF) presenting with broad left bundle branch block (LBBB) or pacemaker dependency. To achieve beneficial effects, CRT requires high bi-ventricular (BiV) pacing rates. Therefore, device-manufacturers designed pacing algorithms which maintain high BiV pacing rates by a left ventricular (LV) pacing stimulus immediately following a right ventricular sensed beat. However, data on clinical impact of these algorithms are sparse. We studied 17 patients implanted with a CRT device providing triggered left ventricular pacing (tLVp) in case of atrioventricular nodal conduction. Assessment of LV dyssynchrony was performed using echocardiographic and electrocardiographic examination while CRT-devices were set to three different settings: 1. Optimized bi-ventricular-stimulation (BiV); 2. Physiological AV nodal conduction (tLVp-off); 3. Physiological AV nodal conduction and tLVp-algorithm turned on (tLVp-on). QRS duration increased when the CRT-device was set to tLVp-off compared to BiV-Stim, while QRS duration was comparable to BiV-Stim with the tLVp-on setting. Echocardiographic analysis revealed higher dyssynchrony during tLVp-off compared to BiV-Stim. TLVp-on did not improve LV dyssynchrony compared to tLVp-off. QRS duration significantly decreased using tLVp-algorithms compared to physiological AV nodal conduction. However, echocardiographic examination could not show functional benefit from tLVp-algorithms, suggesting that these algorithms are inferior to regular biventricular pacing regarding cardiac resynchronization. Therefore, medical treatment and ablation procedures should be preferred, when biventricular pacing rates have to be increased. TLVp-algorithms can be used in addition to these treatment options