scholarly journals Supramolecular Host–Guest Hydrogels for Corneal Regeneration

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 163
Author(s):  
Amy C. Madl ◽  
David Myung
Keyword(s):  
Vision Loss ◽  
Cross Reactivity ◽  
Promising Alternative ◽  
Donor Tissue ◽  
Corneal Regeneration ◽  
Stromal Tissue ◽  
Severe Vision Loss ◽  
High Rejection ◽  
Target Effects

Over 6.2 million people worldwide suffer from moderate to severe vision loss due to corneal disease. While transplantation with allogenic donor tissue is sight-restoring for many patients with corneal blindness, this treatment modality is limited by long waiting lists and high rejection rates, particularly in patients with severe tissue damage and ocular surface pathologies. Hydrogel biomaterials represent a promising alternative to donor tissue for scalable, nonimmunogenic corneal reconstruction. However, implanted hydrogel materials require invasive surgeries and do not precisely conform to tissue defects, increasing the risk of patient discomfort, infection, and visual distortions. Moreover, most hydrogel crosslinking chemistries for the in situ formation of hydrogels exhibit off-target effects such as cross-reactivity with biological structures and/or result in extractable solutes that can have an impact on wound-healing and inflammation. To address the need for cytocompatible, minimally invasive, injectable tissue substitutes, host–guest interactions have emerged as an important crosslinking strategy. This review provides an overview of host–guest hydrogels as injectable therapeutics and highlights the potential application of host–guest interactions in the design of corneal stromal tissue substitutes.

scholarly journals Engineered Phage Endolysin Eliminates Gardnerella Biofilm without Damaging Beneficial Bacteria in Bacterial Vaginosis Ex Vivo

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Christine Landlinger ◽  
Lenka Tisakova ◽  
Vera Oberbauer ◽  
Timo Schwebs ◽  
Abbas Muhammad ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Bactericidal Activity ◽  
High Selectivity ◽  
Ex Vivo ◽  
Vaginal Microbiome ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Promising Alternative ◽  
First Time

Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13–8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.

scholarly journals Effect of Cavity Disinfectants on Adhesion to Primary Teeth—A Systematic Review

2021 ◽  
Vol 22 (9) ◽  
pp. 4398
Author(s):  
Ana Coelho ◽  
Inês Amaro ◽  
Ana Apolónio ◽  
Anabela Paula ◽  
José Saraiva ◽  
...  
Keyword(s):  
Primary Teeth ◽  
Clinical Success ◽  
Dental Materials ◽  
In Vitro Study ◽  
In Vitro Studies ◽  
Cochrane Library ◽  
Promising Alternative

Some authors have been proposing the use of cavity disinfectants in order to reduce, or even eliminate, the effect of the microorganisms present in a dental cavity before a restoration is placed. The aim of this study was to evaluate the effect of different cavity disinfectants on bond strength and clinical success of composite and glass ionomer restorations on primary teeth. The research was conducted using Cochrane Library, PubMed/MEDLINE, SCOPUS, and Web of Science for articles published up to February 2021. The search was performed according to the PICO strategy. The evaluation of the methodological quality of each in vitro study was assessed using the CONSORT checklist for reporting in vitro studies on dental materials. Sixteen in vitro studies and one in situ study fulfilled the inclusion criteria and were analyzed. Chlorhexidine was the most studied cavity disinfectant, and its use does not compromise dentin bonding. Sodium hypochlorite is a promising alternative, but more research on its use is required to clearly state that it can safely be used as a cavity disinfectant for primary teeth. Although other disinfectants were studied, there is a low-level evidence attesting their effects on adhesion, therefore their use should be avoided.

scholarly journals Identification of abnormal tribological regimes using a microphone and semi-supervised machine-learning algorithm

Friction ◽  
2021 ◽  
Author(s):  
Vigneashwara Pandiyan ◽  
Josef Prost ◽  
Georg Vorlaufer ◽  
Markus Varga ◽  
Kilian Wasmer
Keyword(s):  
Machine Learning ◽  
Learning Algorithm ◽  
Industrial Applications ◽  
Supervised Machine Learning ◽  
Normal Operation ◽  
Promising Alternative ◽  
Wear And Tear ◽  
Validation Procedure ◽  
And Performance

AbstractFunctional surfaces in relative contact and motion are prone to wear and tear, resulting in loss of efficiency and performance of the workpieces/machines. Wear occurs in the form of adhesion, abrasion, scuffing, galling, and scoring between contacts. However, the rate of the wear phenomenon depends primarily on the physical properties and the surrounding environment. Monitoring the integrity of surfaces by offline inspections leads to significant wasted machine time. A potential alternate option to offline inspection currently practiced in industries is the analysis of sensors signatures capable of capturing the wear state and correlating it with the wear phenomenon, followed by in situ classification using a state-of-the-art machine learning (ML) algorithm. Though this technique is better than offline inspection, it possesses inherent disadvantages for training the ML models. Ideally, supervised training of ML models requires the datasets considered for the classification to be of equal weightage to avoid biasing. The collection of such a dataset is very cumbersome and expensive in practice, as in real industrial applications, the malfunction period is minimal compared to normal operation. Furthermore, classification models would not classify new wear phenomena from the normal regime if they are unfamiliar. As a promising alternative, in this work, we propose a methodology able to differentiate the abnormal regimes, i.e., wear phenomenon regimes, from the normal regime. This is carried out by familiarizing the ML algorithms only with the distribution of the acoustic emission (AE) signals captured using a microphone related to the normal regime. As a result, the ML algorithms would be able to detect whether some overlaps exist with the learnt distributions when a new, unseen signal arrives. To achieve this goal, a generative convolutional neural network (CNN) architecture based on variational auto encoder (VAE) is built and trained. During the validation procedure of the proposed CNN architectures, we were capable of identifying acoustics signals corresponding to the normal and abnormal wear regime with an accuracy of 97% and 80%. Hence, our approach shows very promising results for in situ and real-time condition monitoring or even wear prediction in tribological applications.

scholarly journals The Positive Legacy of Vision Loss: Pathways to Posttraumatic Growth

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 616-617
Author(s):  
Corinna Tanner ◽  
Michael Caserta ◽  
Jia-Wen Guo ◽  
Margaret Clayton ◽  
Paul Bernstein ◽  
...  
Keyword(s):  
Posttraumatic Growth ◽  
Cognitive Processing ◽  
Mixed Method ◽  
Vision Loss ◽  
Social Issues ◽  
Qualitative Interviews ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Severe Vision Loss ◽  
Age Range

Abstract This mixed method study describes posttraumatic growth (PTG) accruing form experience with vision loss caused by severe age related macular degeneration (AMD) and explores relationships between depression, social support, and cognitive processing, on the path to PTG. Research describing the psychological and social issues surrounding AMD has focused on negative outcomes. However, learning from highly challenging experiences, such as vision loss, can offer benefits. In this study, these included an increased sense of personal strength, increased spirituality, and empathy for others (all domains of PTG). 89 participants with severe vision loss (mean age = 85.3 years, age range = 74–98 years) completed the interviewer-administered composite questionnaire, which identified elements of Tedeschi and Calhoun’s model of PTG. Relationships between variables were examined using path analysis. Findings were contextualized with data from 15 qualitative interviews. Findings underscored the importance of supportive others and deliberate cognitive processing in the path to PTG.

scholarly journals Functional optical coherence tomography of retinal photoreceptors

2018 ◽  
Vol 243 (17-18) ◽  
pp. 1256-1264 ◽  
Author(s):  
Xincheng Yao ◽  
Taeyoon Son ◽  
Tae-Hoon Kim ◽  
Yiming Lu
Keyword(s):  
Vision Loss ◽  
Objective Assessment ◽  
Age Related Macular Degeneration ◽  
Retinal Stimulation ◽  
Age Related ◽  
Retinal Photoreceptors ◽  
Severe Vision Loss ◽  
Further Development

Age-related macular degeneration (AMD) is the leading cause of severe vision loss and legal blindness. It is known that retinal photoreceptors are the primary target of AMD. Therefore, a reliable method for objective assessment of photoreceptor function is needed for early detection and reliable treatment evaluation of AMD and other eye diseases such as retinitis pigmentosa that are known to cause photoreceptor dysfunctions. Stimulus-evoked intrinsic optical signal (IOS) changes promise a unique opportunity for objective assessment of physiological function of retinal photoreceptor and inner neurons. Instead of a comprehensive review, this mini-review is to provide a brief summary of our recent in vitro and in vivo optical coherence tomography (OCT) studies of stimulus-evoked IOS changes in animal retinas. By providing excellent axial resolution to differentiate individual retinal layers, depth-resolved OCT revealed rapid IOS response at the photoreceptor outer segment. The fast photoreceptor-IOS occurred almost right away (∼ 2 ms) after the onset of retinal stimulation, differentiating itself from slow IOS changes correlated with inner neural and hemodynamic changes. Further development of the functional IOS instruments and retinal stimulation protocols may provide a feasible solution to pursue clinical application of functional IOS imaging for objective assessment of human photoreceptors. Impact statement Retinal photoreceptors are the primary target of age-related macular degeneration (AMD) which is the leading cause of severe vision loss and legal blindness. An objective method for functional assessment of photoreceptor physiology can benefit early detection and better treatment evaluation of AMD and other eye diseases that are known to cause photoreceptor dysfunctions. This article summarizes in vitro study of IOS mechanisms and in vivo demonstration of IOS imaging of intact animals. Further development of the functional IOS imaging may provide a revolutionary solution to achieve objective assessment of human photoreceptors.

scholarly journals Introduction to the multi-author review on macular degeneration

2020 ◽  
Vol 77 (5) ◽  
pp. 779-780 ◽  
Author(s):  
Anu Kauppinen
Keyword(s):  
Macular Degeneration ◽  
Vision Loss ◽  
The Elderly ◽  
Developed Countries ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Severe Vision Loss ◽  
Author Review ◽  
Dry Amd ◽  
Endothelial Growth Factor

AbstractProlonged life expectancies contribute to the increasing prevalence of age-related macular degeneration (AMD) that is already the leading cause of severe vision loss among the elderly in developed countries. In dry AMD, the disease culminates into vast retinal atrophy, whereas the wet form is characterized by retinal edema and sudden vision loss due to neovascularization originating from the choroid beneath the Bruch’s membrane. There is no treatment for dry AMD and despite intravitreal injections of anti-vascular endothelial growth factor (VEGF) that suppress the neovessel formation, also wet AMD needs new therapies to prevent the disease progression and to serve patients lacking of positive response to current medicines. Knowledge on disease mechanisms is a prerequisite for the drug development, which is hindered by the multifactorial nature of AMD. Numerous distinguished publications have revealed AMD mechanisms at the cellular and molecular level and in this multi-author review, we take a bit broader look at the topic with some novel aspects.

Treatments Being Developed in Retinitis Pigmentosa

2021 ◽  
pp. 150-154
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Pigment Epithelial ◽  
Vision Loss ◽  
Platelet Rich Plasma ◽  
Retinal Pigment ◽  
Retinal Prostheses ◽  
Pigment Epithelial ◽  
Recent Developments ◽  
Severe Vision Loss ◽  
Experimental Approaches

Recent developments in understanding the pathophysiology of retinitis pigmentosa (RP) have shown that there have been new hopes in the treatment of this disease which can cause severe vision loss. Proven therapy for RP-associated photoreceptor loss and retinal pigment epithelial damage has not yet been reported. New or experimental approaches for the treatment of RP include platelet-rich plasma, gene therapy, transplantation of fetal retinal cells or stem cells, and electronic retinal prostheses.

Better visual outcome associated with early vitrectomy in the management of endophthalmitis

2021 ◽  
pp. bjophthalmol-2020-316846
Author(s):  
Sarah Welch ◽  
Riyaz Bhikoo ◽  
Nancy Wang ◽  
Martin J Siemerink ◽  
William Shew ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Vision Loss ◽  
Endogenous Endophthalmitis ◽  
Health Board ◽  
Surgical Trauma ◽  
District Health ◽  
Early Vitrectomy ◽  
Younger Age ◽  
Severe Vision Loss ◽  
Culture Positive

AimsTo examine the role of early vitrectomy in the management of endophthalmitis from all causes.MethodsRetrospective study of 290 consecutive subjects diagnosed with endophthalmitis at Auckland District Health Board between 1 January 2006 and 31 July 2019. Main outcome measure was visual acuity at 9-month follow-up and proportion of subjects with severe vision loss (≤20/200).ResultsMedian age at presentation was 70.4 years and 151 subjects (52.1%) were women. Cataract surgery was the most common cause of endophthalmitis in 92 subjects (31.7%) followed by intravitreal injection in 57 (19.7%), endogenous endophthalmitis in 48 subjects (16.6%), non-surgical trauma in 42 subjects (14.5%), glaucoma surgery in 24 subjects (8.3%), vitrectomy in 22 subjects (7.6%) and corneal in 5 subjects (1.7%). Culture was positive in 136 (46.9%) with gram-positive organisms most common (76.5%). Early vitrectomy was performed in 82 subjects (28.3%). Median visual acuity at 9 months was 20/100 (IQR 20/30 to light perception), and severe vision loss occurred in 100 (43.5%). Retinal detachment occurred in 35 eyes (12.1%) and 26 eyes were enucleated. On multivariate analysis, younger age, poor presenting visual acuity and culture-positive endophthalmitis were associated with worse outcomes, and early vitrectomy was associated with better outcomes.ConclusionsEarly vitrectomy (within 24 hours) is associated with better visual outcomes at 9 months, while younger age, poor presenting visual acuity and culture-positive endophthalmitis are associated with poorer visual acuity outcomes.

scholarly journals Case Report: Central Retinal Artery Occlusion in a COVID-19 Patient

2020 ◽  
Vol 11 ◽  
Author(s):  
Andrea Montesel ◽  
Claudio Bucolo ◽  
Victoria Mouvet ◽  
Emmanuelle Moret ◽  
Chiara M. Eandi
Keyword(s):  
Vision Loss ◽  
Previous History ◽  
Central Retinal Artery Occlusion ◽  
Retinal Artery Occlusion ◽  
Artery Occlusion ◽  
Central Retinal Artery ◽  
History Of ◽  
Severe Vision Loss ◽  
Retinal Artery ◽  
Vascular Occlusions

We report a case of central retinal artery occlusion (CRAO) in a patient with a previous history of severe COVID-19 disease. This disease has been associated with inflammatory-induced homeostasis changes leading to endothelial dysfunction and a procoagulant state with multi-organ involvement, but the burden of thromboembolic complications in COVID-19 patients is currently unknown. The pathogenesis of retinal artery occlusions is a multifactorial process where inflammation and hypercoagulation state are established risk factors. Even if our experience may represent a coincidental relationship, it is likely that COVID-19 patients could be at risk of developing retinal vascular occlusions. A focused ophthalmological surveillance is advisable to prevent and manage this possible cause of severe vision loss that has an important impact in health care system.

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