“Wet” transepithelial phototherapeutic keratectomy in the management of persistent epithelial defects in the graft

Sergei V Churashov,1 Elena V Kudryashova,1 Alexei N Kulikov,1 Ernest V Boiko,1–3 Valerii F Chernysh,1 Dmitrii S Maltsev1 1Department of Ophthalmology, Military Medical Academy, St Petersburg, Russia; 2St Petersburg Branch, The S Fyodorov Eye Microsurgery Federal State Institution, St Petersburg, Russia; 3Department of Ophthalmology, Mechnikov North-Western State Medical University, St Petersburg, Russia Purpose: This study aimed to evaluate the efficacy of “wet” transepithelial phototherapeutic keratectomy (TE-PTK) for treating persistent epithelial defects (PEDs) in the corneal graft following penetrating keratoplasty (PKP).Methods: This study describes a noncomparative, prospective interventional case series. Patients with post-PKP graft epithelial defects lasting >3 months despite previous treatments with extensive wear soft contact lenses, amniotic membrane transplantation, and tarsorrhaphy were treated with wet TE-PTK. A wet TE-PTK procedure including a “wet ablation” step was performed using the EC-5000 excimer laser. Follow-up visits were at post-PTK days 3, 5, 10, and 30, and at each month thereafter.Results: Eight patients (8 eyes; 5 men and 3 women; mean age, 51.3±14.3 years; mean follow-up period, 9.1±3.0 months) were included in this study. The mean best-corrected visual acuity was 1.76±0.28 log minimum angle of resolution (logMAR) at baseline and improved to 1.1±0.22 logMAR at 10 days postoperatively (p=0.0156; the improvement was significant). This effect remained stable throughout the remainder of the follow-up period. The mean time from wet TE-PTK to complete reepithelization was 4.3±1.3 days.Conclusion: Wet TE-PTK appears to be effective for patients with post-PKP PEDs in the corneal graft who have failed conservative measures or previous surgical interventions. Keywords: phototherapeutic keratectomy, persistent epithelial defects, penetrating keratoplasty, transepithelial phototherapeutic keratectomy, recurrent corneal erosio

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

This review covers all of the common methods for the syntheses of aromatic and heterocyclic perfluoroalkyl sulfides, a class of compounds which is finding increasing application as starting materials for the preparation of agrochemicals, pharmaceutical products and, more generally, fine chemicals. A systematic approach is taken depending on the mode of incorporation of the SRF groups and also on the type of reagents used

Liquid-crystalline dimers composed of bent-core mesogenic units RID E-1562-2011

Systematic studies on symmetric twin molecules composed of two bent-core mesogenic units are reported for the first time. It is shown that the formation of mesophases mainly depends on the chemical structure of the spacer. A sufficiently flexible spacer containing dimethylsiloxane units allows a decoupling of the mesogenic moieties; the related compounds exhibit a ferroelectric SmCP phase proved by electro-optical measurements. On the basis of X-ray data, a plausible structure model is presented. The connection of two bent-core mesogenic units by means of a tetraethylene glycol spacer results in dimers. which are able to form columnar phases. For twins containing a simple hydrocarbon chain as spacer, in most cases liquid-crystalline behavior could not be detected. These general tendencies remain valid if the bent-core unit is changed, e.g., by increasing the number of aromatic rings, by lateral substitution, and by inversion of the direction of one of the connecting groups between the aromatic rings, respectively. The mesophase behavior of the new dimers is compared with that of the corresponding single-unit compounds as well as a related dendrimer and a polymer. It is of interest that the antiferroelectric switching behavior found for the nonchiral '' monomeric '' compounds is changed to a ferroelectric behavior for the dimeric compounds