scholarly journals Fourier-Domain OCT Imaging of the Ocular Surface and Tear Film Dynamics: A Review of the State of the Art and an Integrative Model of the Tear Behavior during the Inter-Blink Period and Visual Fixation

2020 ◽  
Vol 9 (3) ◽  
pp. 668 ◽  
Author(s):  
Pietro Emanuele Napoli ◽  
Matteo Nioi ◽  
Lorenzo Mangoni ◽  
Pietro Gentile ◽  
Mirco Braghiroli ◽  
...  
Keyword(s):  
Ocular Surface ◽  
State Of The Art ◽  
Tear Film ◽  
The State ◽  
Visual Fixation ◽  
Image Resolution ◽  
Integrative Model ◽  
Fourier Domain ◽  
Oct Imaging

In the last few decades, the ocular surface and the tear film have been noninvasively investigated in vivo, in a three-dimensional, high resolution, and real-time mode, by optical coherence tomography (OCT). Recently, OCT technology has made great strides in improving the acquisition speed and image resolution, thus increasing its impact in daily clinical practice and in the research setting. All these results have been achieved because of a transition from traditional time-domain (TD) to Fourier-domain (FD) technology. FD-OCT devices include a spectrometer in the receiver that analyzes the spectrum of reflected light on the retina or ocular surface and transforms it into information about the depth of the structures according to the Fourier principle. In this review, we summarize and provide the state-of-the-art in FD-OCT imaging of the ocular surface system, addressing specific aspects such as tear film dynamics and epithelial changes under physiologic and pathologic conditions. A theory on the dynamic nature of the tear film has been developed to explain the variations within the individual compartments. Moreover, an integrative model of tear film behavior during the inter-blink period and visual fixation is proposed.

Tocotrienols and Cancer: From the State of the Art to Promising Novel Patents

2019 ◽  
Vol 14 (1) ◽  
pp. 5-18 ◽  
Author(s):  
Fabrizio Fontana ◽  
Michela Raimondi ◽  
Monica Marzagalli ◽  
Roberta M. Moretti ◽  
Marina Montagnani Marelli ◽  
...  
Keyword(s):  
Cancer Prevention ◽  
State Of The Art ◽  
Synergistic Effects ◽  
The State ◽  
Therapeutic Interventions ◽  
Multiple Tumor ◽  
Anti Cancer ◽  
Important Health

Background: Tocotrienols (TTs) are vitamin E derivatives naturally occurring in several plants and vegetable oils. Like Tocopherols (TPs), they comprise four isoforms, α, β, γ and δ, but unlike TPs, they present an unsaturated isoprenoid chain. Recent studies indicate that TTs provide important health benefits, including neuroprotective, anti-inflammatory, anti-oxidant, cholesterol lowering and immunomodulatory effects. Moreover, they have been found to possess unique anti-cancer properties.Objective:The purpose of this review is to present an overview of the state of the art of TTs role in cancer prevention and treatment, as well as to describe recent patents proposing new methods for TTs isolation, chemical modification and use in cancer prevention and/or therapy.Methods:Recent literature and patents focusing on TTs anti-cancer applications have been identified and reviewed, with special regard to their scientific impact and novelty.Results:TTs have demonstrated significant anti-cancer activity in multiple tumor types, both in vitro and in vivo. Furthermore, they have shown synergistic effects when given in combination with standard anti-cancer agents or other anti-tumor natural compounds. Finally, new purification processes and transgenic sources have been designed in order to improve TTs production, and novel TTs formulations and synthetic derivatives have been developed to enhance their solubility and bioavailability.Conclusion:The promising anti-cancer effects shown by TTs in several preclinical studies may open new opportunities for therapeutic interventions in different tumors. Thus, clinical trials aimed at confirming TTs chemopreventive and tumor-suppressing activity, particularly in combination with standard therapies, are urgently needed.

scholarly journals Deep Compressed Sensing for Learning Submodular Functions

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2591 ◽  
Author(s):  
Yu-Chung Tsai ◽  
Kuo-Shih Tseng
Keyword(s):  
Compressed Sensing ◽  
Fourier Coefficients ◽  
State Of The Art ◽  
The State ◽  
Submodular Functions ◽  
Fourier Domain ◽  
3D Mapping ◽  
Target Search ◽  
Approach To Learning ◽  
Benchmark Approach

The AI community has been paying attention to submodular functions due to their various applications (e.g., target search and 3D mapping). Learning submodular functions is a challenge since the number of a function’s outcomes of N sets is 2 N . The state-of-the-art approach is based on compressed sensing techniques, which are to learn submodular functions in the Fourier domain and then recover the submodular functions in the spatial domain. However, the number of Fourier bases is relevant to the number of sets’ sensing overlapping. To overcome this issue, this research proposed a submodular deep compressed sensing (SDCS) approach to learning submodular functions. The algorithm consists of learning autoencoder networks and Fourier coefficients. The learned networks can be applied to predict 2 N values of submodular functions. Experiments conducted with this approach demonstrate that the algorithm is more efficient than the benchmark approach.

scholarly journals Role of ion channels in the functional response of conjunctival goblet cells to dry eye

2018 ◽  
Vol 315 (2) ◽  
pp. C236-C246 ◽  
Author(s):  
Donald G. Puro
Keyword(s):  
Ion Channels ◽  
Dry Eye ◽  
Ocular Surface ◽  
Adaptive Response ◽  
Tear Film ◽  
Goblet Cells ◽  
Cation Conductance ◽  
Conjunctival Goblet Cells

Optimal vision requires an ocular surface with a stable tear film whose many critical tasks include providing >70% of the eye’s refractive power. However, for millions, tear film instability produces uncomfortable sight-impairing dry eye. Despite the multitude of etiologies for dry eye, a universal hallmark is hyperosmolarity of the tear film. Presently, knowledge of how the ocular surface responds to hyperosmolarity remains incomplete with little understood about the role of ion channels. This bioelectric analysis focused on conjunctival goblet cells whose release of tear-stabilizing mucin is a key adaptive response to dry eye. In freshly excised rat conjunctiva, perforated-patch recordings demonstrated that a ≥10% rise in osmolarity triggers goblet cells to rapidly generate a ~15-mV hyperpolarization due to the oxidant-dependent activation of ATP-sensitive K+ (KATP) channels. High-resolution membrane capacitance measurements used to monitor exocytosis revealed that this hyperpolarization results in an approximately fourfold boost in exocytotic activity evoked by cholinergic input, which in vivo occurs via a neural reflex and depends chiefly on calcium influxing down its electro-gradient. We discovered that this adaptive response is transient. During 30–80 min of hyperosmolarity, development of a depolarizing nonspecific cation conductance fully counterbalances the KATP-driven hyperpolarization and thereby eliminates the exocytotic boost. We conclude that hyperosmotic-induced hyperpolarization is a previously unappreciated mechanism by which goblet cells respond to transient ocular dryness. Loss of this voltage increase during long-term dryness/hyperosmolarity may account for the clinical conundrum that goblet cells in chronically dry eyes can remain filled with mucin even though the tear film is hyperosmotic and mucin-deficient.

scholarly journals Triclosan in Toothpaste, Is There Any Real Risk for the Health?

2016 ◽  
Vol 18 (2) ◽  
pp. 41
Author(s):  
Gabriela García C.D. ◽  
Alejandra Sánchez C.D., M.C. ◽  
Edith Galindo C.D., M.C., PhD. ◽  
Bernardino Cerda C.D., M.C., PhD.
Keyword(s):  
Public Opinion ◽  
State Of The Art ◽  
Endocrine System ◽  
The State ◽  
Toxic Action ◽  
Toxic Effects ◽  
Cellular Mechanisms ◽  
Real Risk

Triclosan is an antimicrobial drug that is widely used in products for human hygiene, beauty and home cleanliness. It is a common compound in toothpaste that have showed efficacy on the control and treatment of gingivitis. However, during the last decade, the triclosan has been extensively investigated because of its cytotoxicity, its ability to disturb cellular mechanisms on endocrine-system cells, and because of its cancerogenic in vitro and in vivo properties. Moreover, public opinion has paid attention to the toxic action of the triclosan. Thus, the dentist should know the state of the art about the detrimental effects of triclosan on patients’ health. This review explores the triclosan on its cytotoxicity, in vitro and in vivo cancerogenic effects, absorption in humans, and the toxic effects caused by triclosan toothpaste.

scholarly journals Comparative characteristics of osmolarity, tear production and state of the corneal epithelium after instillations of the preparations Visomitin and hypromellose

2021 ◽  
pp. 249-255
Author(s):  
T. N. Safonova ◽  
Z. V. Surnina ◽  
G. V. Zaitseva
Keyword(s):  
Ocular Surface ◽  
Tear Film ◽  
Quantitative Composition ◽  
Blurred Vision ◽  
Ocular Symptoms ◽  
Increased Sensitivity ◽  
Corneal Staining ◽  
Positive Effect ◽  
Inflammatory Action

Introduction. Dry eye syndrome (DES) is a multifactorial disease of the ocular surface, characterized by changes in its homeostasis and accompanied by ocular symptoms, the etiology of which is associated with destabilization of the tear film, hyperosmolarity, inflammation, damage to the structures of the ocular surface and neurosensory disorders.Objective. To study the effect of a drug containing plastoquinonyldecyltriphenylphosphonium bromide (PDTP, SkQ1) on dynamics of osmolarity and reparative properties of the cornea.Materials and methods. The study included 23 patients (46 eyes) aged 23 to 49 years. All patients presented complaints of dryness, burning sensation, cramps and discomfort in the eyes, increased sensitivity with instillation of drops, periodic blurred vision. Patients underwent standard and special ophthalmic examinations. The patients were divided into two groups comparable in gender and quantitative composition.Results. Based on the results of the examination at the starting visit, all patients were diagnosed with DES mild or moderate study. After one week of therapy, a significant decrease in subjective complaints was noted patients who received the drug with PDTF. All patients tolerated the drug well. In the group of patients who received a tear replacement therapy with hypromellose, in most patients, while complaints of dryness persist, decreased a feeling of pain in the eyes. A month later, complaints persisted only in patients of this group, but their intensity was known significantly reduced compared to the visit after a week. Against the background of therapy with the drug with PDTP, significant improvement of the Schirmer test, Norn test and corneal staining, as well as with the help of a in vivo confocal microscopy shows a decrease in the number of Langerhans cells.Conclusion. The results obtained indicate a positive effect of PDTP on the structure of the ocular surface even with its short-term use due to its keratoprotective and anti-inflammatory action. 

scholarly journals Non-Equilibrium Living Polymers

2020 ◽  
Author(s):  
D. Michieletto
Keyword(s):  
Soft Matter ◽  
State Of The Art ◽  
The State ◽  
Synthetic Chemistry ◽  
Art Of Living ◽  
Living Polymers ◽  
Insight Into ◽  
Non Equilibrium

Systems of “living” polymers are ubiquitous in industry and are traditionally realised using surfactants. Here I review the state-of-the-art of living polymers and discuss non-equilibrium extensions that may be realised with advanced synthetic chemistry or DNA functionalised by proteins. These systems are not only interesting in order to realise novel “living” soft matter but can also shed insight into how genomes are (topologically) regulated in vivo.

scholarly journals In VivoLaser Scanning Confocal Microscopy of Human Meibomian Glands in Aging and Ocular Surface Diseases

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Vincenzo Fasanella ◽  
Luca Agnifili ◽  
Rodolfo Mastropasqua ◽  
Lorenza Brescia ◽  
Federico Di Staso ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Dry Eye ◽  
Ocular Surface ◽  
Tear Film ◽  
Response To Therapy ◽  
Tissue Response ◽  
Scanning Confocal Microscopy ◽  
Ocular Surface Diseases ◽  
Meibomian Glands

Meibomian glands (MGs) play a crucial role in the ocular surface homeostasis by providing lipids to the superficial tear film. Their dysfunction destabilizes the tear film leading to a progressive loss of the ocular surface equilibrium and increasing the risk for dry eye. In fact, nowadays, the meibomian gland dysfunction is one of the leading causes of dry eye. Over the past decades, MGs have been mainly studied by using meibography, which, however, cannot image the glandular structure at a cellular level. The diffusion of thein vivolaser scanning confocal microscopy (LSCM) provided a new approach for the structural assessment of MGs permitting a major step in the noninvasive evaluation of these structures. LSCM is capable of showing MGs modifications during aging and in the most diffuse ocular surface diseases such as dry eye, allergy, and autoimmune conditions and in the drug-induced ocular surface disease. On the other hand, LSCM may help clinicians in monitoring the tissue response to therapy. In this review, we summarized the current knowledge about the role ofin vivoLSCM in the assessment of MGs during aging and in the most diffuse ocular surface diseases.

scholarly journals Contribution of Mucins towards the Physical Properties of the Tear Film: A Modern Update

2019 ◽  
Vol 20 (24) ◽  
pp. 6132 ◽  
Author(s):  
Georgi As. Georgiev ◽  
Petar Eftimov ◽  
Norihiko Yokoi
Keyword(s):  
Ocular Surface ◽  
Tear Film ◽  
The Novel ◽  
Mucin Secretion ◽  
Lipid Layer ◽  
The Impact ◽  
Ophthalmic Disease

Instability of the tear film (TF) protecting the ocular surface results in dry eye syndrome (DES), the most prevalent public health ophthalmic disease affecting the quality of life of 10 to 30% of the human population worldwide. Although the impact of the tear film lipid layer (TFLL) and of the aqueous tears (AT) to the TF stability is extensively studied, in contrast the contribution of the secretory mucins (SM) and of the membrane-associated mucins (MAM), i.e., one of the most abundant molecular classes in AT and in the corneal epithelium respectively, remains poorly defined. However, it is well known that in DES both types of mucins are quantitatively or qualitatively deficient. Numerous studies since the 1990s until now have proposed direct involvement of SM and MAM in the material properties (viscoelasticity, hydration, and protection of the ocular surface; synergistic cooperation with the rest of the TF layers; etc.) and stability of TF. These theories will be reviewed here in the context of the classical and modern in vitro and in vivo results that allow their reappraisal and in view of the novel mucin secretion enhancing pharmaceuticals, which have opened innovative routes for the therapy of DES.

Fourier domain OCT imaging of the human eye in vivo

2002 ◽  
Author(s):  
Maciej Wojtkowski ◽  
Rainer Leitgeb ◽  
Andrzej Kowalczyk ◽  
Adolf F. Fercher
Keyword(s):  
Fourier Domain ◽  
Human Eye ◽  
Oct Imaging ◽  
Fourier Domain Oct
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