scholarly journals Substitutes and Colloidal System for Vitreous Replacement and Drug Delivery: Recent Progress and Future Prospective

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 121
Author(s):  
Minal Thacker ◽  
Ching-Li Tseng ◽  
Feng-Huei Lin
Keyword(s):  
Recent Progress ◽  
Silicone Oil ◽  
Vitreous Body ◽  
Colloidal System ◽  
Experimental Phase ◽  
Short Term ◽  
Vitreous Substitute ◽  
Pathological Conditions ◽  
Macular Holes

Vitreoretinal surgeries for ocular diseases such as complicated retinal detachment, diabetic retinopathy, macular holes and ocular trauma has led to the development of various tamponades over the years in search for an ideal vitreous substitute. Current clinically used tamponade agents such as air, perfluorocarbons, silicone oil and expansile gases serve only as a short-term solution and harbors various disadvantages. However, an ideal long-term substitute is yet to be discovered and recent research emphasizes on the potential of polymeric hydrogels as an ideal vitreous substitute. This review highlights the recent progress in the field of vitreous substitution. Suitability and adverse effects of various tamponade agents in present day clinical use and biomaterials in the experimental phase have been outlined and discussed. In addition, we introduced the anatomy and functions of the native vitreous body and the pathological conditions which require vitreous replacement.

Biomedical Materials to Repair Retinal Detachments

1985 ◽  
Vol 55 ◽  
Author(s):  
Miguel F. Refojo
Keyword(s):  
Retinal Detachment ◽  
Silicone Rubber ◽  
Methyl Acrylate ◽  
Silicone Oil ◽  
Vitreous Body ◽  
Light Sensitivity ◽  
Scleral Buckling ◽  
Intraocular Injection ◽  
Other Substances

ABSTRACTImplants are essential for the repair of retinal detachments. The implant buckles the wall of the eye and apposes the detached retina with the choroid, thus restoring light sensitivity to the retina. The scleral buckling also relieves traction on the retina from a shrinking vitreous body. The implant materials most commonly used are solid silicone rubber and silicone sponges, but both types have some disadvantages. A poly(hydroxyethyl acrylate-co-methyl acrylate) hydrogel implant with improved properties of softness and antibiotic absorption is also available for retinal detachment surgery. Proliferative vitreoretinopathy involves various conditions of retinal detachment complicated by vitreous fibrosis, which, after vitrectomy, may be treated with intraocular injection of fluids that support the retina against the choroid. For conditions requiring a long-term implant, silicone oil although controversial is the material of choice. Many other substances have been investigated but none better has yet been found.

scholarly journals Vitreous Substitutes: The Present and the Future

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Simone Donati ◽  
Simona Maria Caprani ◽  
Giulia Airaghi ◽  
Riccardo Vinciguerra ◽  
Luigi Bartalena ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Vitreous Body ◽  
Vitreoretinal Surgery ◽  
Inflammatory Reactions ◽  
Vitreous Substitute ◽  
The Past ◽  
The Future ◽  
Vitreous Substitutes ◽  
The Ideal

Vitreoretinal surgery has advanced in numerous directions during recent years. The removal of the vitreous body is one of the main characteristics of this surgical procedure. Several molecules have been tested in the past to fill the vitreous cavity and to mimic its functions. We here review the currently available vitreous substitutes, focusing on their molecular properties and functions, together with their adverse effects. Afterwards we describe the characteristics of the ideal vitreous substitute. The challenges facing every ophthalmology researcher are to reach a long-term intraocular permanence of vitreous substitute with total inertness of the molecule injected and the control of inflammatory reactions. We report new polymers with gelification characteristics and smart hydrogels representing the future of vitreoretinal surgery. Finally, we describe the current studies on vitreous regeneration and cell cultures to create new intraocular gels with optimal biocompatibility and rheological properties.

scholarly journals Thermal Treatment of Aerosol Deposited NiMn2O4 NTC Thermistors for Improved Aging Stability

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3982 ◽  
Author(s):  
Michaela Schubert ◽  
Christian Münch ◽  
Sophie Schuurman ◽  
Véronique Poulain ◽  
Jaroslaw Kita ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Electrode Materials ◽  
Silicone Oil ◽  
Negative Temperature ◽  
Aerosol Deposition ◽  
Short Term ◽  
Long Term Stability ◽  
High Temperature Xrd ◽  
Ntc Thermistor

This paper examines the influence of a short-term thermal treatment of aerosol deposited negative temperature coefficient (NTC) thermistor films on the NTCR characteristics and their long-term stability with different electrode materials. An aerosol deposition of a spinel-based NiMn2O4 powder on alumina substrates with screen-printed AgPd and Au interdigital electrode structures was performed. The manufactured components of the typical size of 1206 were tempered in a moderate temperature range of 200 °C to 800 °C and aged for 1000 h at 125 °C in air. Based on R-T measurements in a high-precision silicone oil thermostat bath and high temperature XRD analyses, the influence of the thermal treatment was analyzed and discussed. A 60-min tempering at 400 °C proved to be optimal, as both the NTCR parameters and their ageing stability could be significantly improved. The findings are explained.

scholarly journals Preliminary Study on Retinal Vascular and Oxygen-related Changes after Long-term Silicone Oil and Foldable Capsular Vitreous Body Tamponade

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Wei Yang ◽  
Yongguang Yuan ◽  
Yao Zong ◽  
Zhen Huang ◽  
Shuyi Mai ◽  
...  
Keyword(s):  
Silicone Oil ◽  
Vitreous Body ◽  
Preliminary Study

scholarly journals AN EXPERIMENTAL STUDY OF A NOVEL DOMESTIC VITREOUS SUBSTITUTE “VITREOLON” IN COMPARISON WITH SILICONE OIL IN SIMULATED RETINAL DETACHMENT IN RABBITS

Biomeditsina ◽  
2019 ◽  
pp. 78-89
Author(s):  
I. B. Alekseyev ◽  
A. R. Korigodskiy ◽  
E. N. Iomdina ◽  
A. A. Fedorov ◽  
V. E. Belkin ◽  
...  
Keyword(s):  
Experimental Study ◽  
Retinal Detachment ◽  
Silicone Oil ◽  
Physiological State ◽  
Vitreous Body ◽  
Ophthalmic Surgery ◽  
Experimental Animals ◽  
Clinical Conditions ◽  
Observation Period

This article presents the results of an experimental study of a new domestic preparation “Vitreolon”, an artifi cial vitreous body based on a weakly cross-linked hydrogel. The safety and effi cacy of this product for the treatment of retinal detachment in experimental animals was evaluated in comparison with silicone oil. The tamponade properties of each drug, their effect on the internal structure of the animal’s eye, convenience and safety of use in ophthalmic surgery were investigated. A base for conducting detailed preclinical and clinical trials was prepared.Rabbits of the gray chinchilla breed were chosen for the study, largely because the size of their eye is close to that of the human eye. This fact allowed us to study the effect of “Vitreolon” in an amount approximately equal to that used in clinical conditions. During the experiment, the indicators of ophthalmological examinations of experimental animals were recorded. The physiological state of the animals was controlled daily. The observation period ranged from 3 months (for rabbits with a silicone tamponade) to 6 months (for rabbits with a tamponade using the new hydrogel artificial vitreous body).It is found that “Vitreolon” is not inferior to silicone oil in terms of tamponade properties. Moreover, it boasts a number of signifi cant advantages, such as a lack of emulsifi cation, absence of migration to the anterior chamber of the eye, no effect on the exchange of intraocular fl uid, no effect on the intraocular pressure (IOP), long-term retention of the shape and transparency. The characteristics of the new hydrogel artifi cial vitreous body are close to those of the native vitreous body. The application of “Vitreolon” in ophthalmic surgery will increase the effi cacy of retinal detachment treatment by reducing the recovery time.

scholarly journals Foldable capsular vitreous body implantation for treatment of traumatic retinal detachment: two case reports

2021 ◽  
Vol 49 (2) ◽  
pp. 030006052199025
Author(s):  
Baihui Zeng ◽  
Qian Wang ◽  
Guiqin Sui ◽  
Mingxuan Wang ◽  
Wei Xie ◽  
...  
Keyword(s):  
Retinal Detachment ◽  
Large Scale ◽  
Silicone Oil ◽  
Case Reports ◽  
Vitreous Body ◽  
Clinical Applications ◽  
Current Evidence ◽  
Vitreoretinal Disease ◽  
Silicone Oil Tamponade

Retinal detachment caused by severe ocular trauma is a type of refractory vitreoretinal disease. Current treatment methods include vitrectomy combined with silicone oil tamponade. However, long-term use of silicone oil tamponade has various complications, including a risk of silicone oil dependence that eventually leads to eyeball atrophy and enucleation. Foldable capsular vitreous bodies (FCVBs) offer a good solution for these problems. However, FCVBs have not been used in large-scale clinical applications and few cases have been reported in the published literature. The main use of FCVBs, based on current evidence, is in the treatment of the relatively few (but important) patients whose eyes have no visual potential; the aim of treatment in these patients is globe preservation, rather than restoration of vision. Here, we describe two patients who underwent FCVB implantation. The findings in these patients indicated that FCVBs can effectively support the vitreous cavity and detached retina. FCVB implantation may thus offer a safe and effective method for treatment of severe retinal detachment, avoiding the inconvenience caused by silicone oil dependence and enucleation. To confirm its long-term usefulness in clinical applications, many additional case reports are needed.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

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