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Use of the temporary keratoprosthesis in ocular trauma repair
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Maurice B Landers III, Steven M Williams
The trephine is centered on the cornea whenever possible; this location is preferred even in the setting of a freshly closed corneal wound. Partial trephinization of the corneal button is performed with a handheld trephine. The corneal button then can be excised with a diamond knife and microcorneal scissors.
Gene Therapy for Retinal Disease
Published in Glenn J. Jaffe, Paul Ashton, P. Andrew Pearson, Intraocular Drug Delivery, 2006
Albert M. Maguire, Jean Bennett
Studies evaluating gene therapy approaches to various ocular conditions have largely involved in vivo application in laboratory animals. Although many ocular cell types such as RPE cells and photoreceptors can be maintained in culture, the biology of these cells in vitro may change in fundamental ways that do not reflect their behavior in vivo. Cell lines in culture often show entirely different expression patterns than the analogous cells in vivo. In addition, in vitro experiments cannot be used to evaluate other variables that may determine stability of gene expression and toxicity of therapy. For example, whereas adenoviral vectors cause minimal cytopathologic effects after in vitro transfection, immune-mediated inflammatory response can cause significant toxicity with in vivo gene therapy (33–35). In vivo experiments can reveal other potential interactions distant from the target tissue. In vivo transduction of ganglion cells has demonstrated that transgene product may appear anywhere along the axonal projections in the central nervous system, e.g., lateral geniculate body and superior colliculus (36). Such information cannot be established in vitro either in isolated cells in cell culture or even in a more complex microenvironment of tissue or organ culture. Ex vivo gene therapy has been explored for corneal diseases and as a way to achieve long-term delivery of exogenous growth factors. In the first instance, corneal buttons are treated in ex vivo conditions to achieve transduction of target cells, e.g., corneal endothelium (37,38). The gene therapy–treated corneal “button” is then transplanted to the animal recipient. The exposed corneal cells maintain expression of the novel gene after transplantation. This form of approach may be particularly well suited for treatment of donor tissue used in various anterior segment procedures such as penetrating keratoplasty. This sort of treatment may also be useful for delivering growth factors that may sustain diseased retinal tissue. Such an approach may ultimately be useful in the transplantation of RPE cells, from which primary cultures can be made with relative ease. RPE cells that have been genetically modified ex vivo have been successfully transplanted to recipient retinas in in vivo studies (39,40).
Chitosan-coated bovine serum albumin nanoparticles for topical tetrandrine delivery in glaucoma: in vitro and in vivo assessment
Published in Drug Delivery, 2022
Salma El-Sayed Radwan, Riham M. El-Moslemany, Radwa A. Mehanna, Eman H. Thabet, Elsayeda-Zeinab A. Abdelfattah, Amal El-Kamel
Isolation of corneal stromal fibroblasts from adult rats was done using a corneal explant protocol (Nagymihaly & Moe, 2020). Briefly the adult male rats were sacrificed, and the eyeballs were dissected out in a petri dish in PBS. The corneal-limbal junction was identified and the corneal button was carefully dissected out using sharp scissors. The corneal button was placed in dispase II solution consisting of 15 mg/ml dispase II, 100 mM Sorbitol, and 1% penicillin/streptomycin in DMEM high glucose basal medium, on ice. The dispase was washed out twice with PBS. In a culture dish, the corneal tissue was cut into 2 × 2 mm pieces and plated in a 12- well plate. Culture medium (DMEM high glucose, 10% FBS, 1% penicillin/streptomycin, Lonza, Basel, Switzerland) was added to the plate to cover the tissue explants (200–250 μL) and then incubated in 5% CO2 and 37 °C. After the first day, the culture medium was added up to 1–1.5 mL to the wells with the corneal explants. The media were refreshed every 3–4 days. Once spindle adherent cells from tissue explants reached 80-90% confluency, they were trypsinized using 0.25% trypsin EDTA (Lonza, Basel, Switzerland) and expanded in larger T75 cm2 flasks (Nagymihaly & Moe, 2020).
Systemic Miltefosine as an Adjunct Treatment of Progressive Acanthamoeba Keratitis
Published in Ocular Immunology and Inflammation, 2021
Andrea Naranjo, Jaime D. Martinez, Darlene Miller, Rahul Tonk, Guillermo Amescua
To the best of our knowledge, there are very few reports on the use of oral MLT in vivo.19 One case of disseminated Acanthamoeba infection after a heart transplant demonstrated MLT’s possible use in solid organ transplantation infections21 and one case of refractory AK reported the use of MLT to prevent the possibility of spread to optic nerve during enucleation.22 A recent publication demonstrated oral MLT was used on a patient with recurrence of AK after 2 therapeutic keratoplasties. No recurrence was seen after a third corneal graft and the removed corneal button was negative for micoorganisms.23 The purpose of this article is to report our experience with the first five patients we have treated with this novel medication for recalcitrant AK.
Factors Affecting Formation of Type-1 and Type-2 Big Bubble during Deep Anterior Lamellar Keratoplasty
Published in Current Eye Research, 2019
Jinyang Li, Wei Chen, Zelin Zhao, Haiou Wang, Qian Gui, Vishal Jhanji, Qinxiang Zheng
Following this procedure, one of the four previously mentioned bubble types would be seen. Corneal stromal separation was then performed for type-1 BB or mixed bubbles. In cases where a clear margin type-2 BB or failed BB occurred, additional deeper manual “wet-peeling” dissection was performed.10 Iris forceps (Iris Forceps 4-101s; Rumex Inc., Clearwater, USA, each tooth of iris forceps is 0.063 mm long) were used to deepen the trephination groove to approximately 80–90% depth. Next, a modified blunt-tipped iris spatula (Xiehe Medical Instruments Company, Suzhou, China; the narrow tip is 0.24*0.50 mm and the wide tip is 0.12*0.80 mm) was inserted carefully into the pocket using slow gliding movements. The separated partial-thickness lamella was excised using a pair of blunt-tipped scissors. Significant edema of residual stromal fibers was observed above the type-2 BB after irrigation with sterile hypotonic water. This facilitates the creation of another stromal pocket and subsequent dissection. The small bubbles in stroma or stromal emphysema indicate the residual corneal stroma. Further dissection was undertaken to remove the residual corneal stroma until there was no corneal emphysema to reach the pre-Descemetic stromal level. The type-2 BB was then expelled using a 15-degree knife or iris forceps. To conclude the procedure, a DM-off donor corneal button with a diameter 0.25 mm larger than the recipient bed was sutured on to the host bed using 10–0 nylon sutures.