Causes that influence the detachment rate after Descemet membrane endothelial keratoplasty.

PURPOSE: To investigate Descemet graft (DG) detachment rate after Descemet membrane endothelial keratoplasty (DMEK) in relation to DG position. METHODS: A total of 175 consecutive pseudophakic eyes that underwent DMEK (175 eyes for Fuchs endothelial dystrophy) from September 2009 through February 2014 at the Tübingen Eye Hospital DG position were studied retrospectively by surgical video at the end of an operation. A group of 45 eyes showed a decentration of the DG with a stromal gap of ≥1.5 mm over at least 3 clock hours between the descematorhexis edge and the DG. DG detachment was documented at a mean follow-up of 13.9 ± 3.7 months after surgery. DG detachment was defined as a detachment of 20 % or more of the DG surface area. Various donor characteristics and patient characteristics were analyzed. RESULTS: The best spectacle-corrected visual acuity (BCVA) in the group of eyes with central well-positioned DG differed significantly from those of eyes with decentered DG. The preoperative BCVA in the central well-positioned DG group was 0.63 ± 0.40 logMAR, and in the decentered DG group 0.91 ± 0.51 logMAR (P < 0.001). The postoperative BCVA in the group of eyes with central well-positioned DG was 0.12 ± 0.11 logMAR, and in the group with decentered DG 0.23 ± 0.29 logMAR (P < 0.001). Endothelial cell density and patient characteristics such as age, gender, and intraocular pressure did not differ significantly between the two groups. The group of eyes with central well-positioned DG showed DG detachment in 12 %; the group with decentered DG findings had DG detachment in 87 % (P < 0.001) at the 12 month follow up. CONCLUSION: The present findings demonstrate the importance of central well-positioned DG and the relation of disease severity. Central well-positioned DG may reduce the incidence of DG detachment. Overlapping of the donor DG and the host Descemet membrane seems to be responsible for DG detachment. One possible way to enhance graft adhesion could be a larger descematorhexis, which avoids an overlapping. The second possible way could be not waiting too long for surgery to reduce disease severity.

[Using intracameral cefuroxime reduces postoperative endophthalmitis rate: 5 years experience at the University Eye Hospital Tübingen]. / Reduktion der postoperativen Endophthalmitisrate durch intrakamerale Cerfuroximgabe: Ergebnisse aus 5 Jahren Erfahrungen an der Universitäts-Augenklinik Tübingen.

BACKGROUND: Cataract surgery is the most commonly performed surgical procedure in developed countries. The annual number of cataract surgeries in Germany is about 600,000. Acute postoperative endophthalmitis is a very severe and the most dreaded complication of cataract surgery. Various operative and non-operative measures have been suggested to prevent this serious complication. The European Society of Cataract & Refractive Surgeons (ESCRS) study of intracameral cefuroxime was the first prospective, randomised and partially placebo-controlled clinical trial showing the efficacy of antibiotic prophylaxis to prevent endophthalmitis in 2007. The aim of this retrospective study is to investigate a possible reduction of intracameral cefuroxime to prevent postoperative endophthalmitis at the University Eye Hospital Tübingen. PATIENTS AND METHODS: During the period from January 2002 to August 2013, 2 time periods were determined based on the adoption of intracameral cefuroxime injections after cataract surgery. From January 2002 to May 2009 patients received at the end of cataract surgery a subconjunctival administration of 50 mg of mezlocillin and postoperative antibiotic eye drops (gentamicin) without intracameral injection. From June 2009 to August 2013, patients received an intracameral injection of cefuroxime while antibiotic drops (moxifloxacin) were used too. The rates of postoperative infectious endophthalmitis during these 2 periods were calculated. RESULTS: 31 cases of endophthalmitis occurred in 31,386 cataract surgeries. The overall cumulative incidence was 0.99 per 1000 patients. The incidence in the first period without intracameral cefuroxime injection was 1.38 (95 % confidence interval [CI]: 1.03-1.72) per 1000 patients and in the second period 0.44 (95 % CI: 0.34-0.54) per 1000 patients (p < 0.001). CONCLUSION: Intracameral injection of cefuroxime reduces the rate of postoperative infectious endophthalmitis in cataract surgery significantly.

Structure solution and refinement of beam-sensitive nano-crystals.

Radiation sensitive materials are among the most difficult materials to study, even more so if they exist only as nanometer-sized particles, where their size is either intentional because of enhanced properties at the nano-scale or it is unintentional because it is impossible to obtain bigger particles of the same structure. In both cases characterization methods need to be optimized to get the most information out of these particles before the radiation damages them to a point where their structure is altered. When the particles are crystallized, both characteristics, the small size and the beam sensitivity, call for electron diffraction as a privileged investigation tool. The strong interaction of electrons (as compared to X-rays) with matter allows single crystal diffraction experiments on nanometer-sized crystals and for the same amount of beam damage, electron diffraction yields more information than X-rays. These inherent advantages of electron diffraction are optimized in the recently developed low-dose electron diffraction tomography (LD-EDT) by minimizing the necessary dose for a complete data collection. In this contribution we show that in some cases even doses as low as 2 e-/Ų can induce damage in crystal structures that inhibit a correct structure refinement. However, by LD-EDT we can obtain data using extremely low doses that don't alter the structure which make it then possible not only to solve crystal structures but also to refine them using dynamical diffraction theory. Here a synthetic oxide containing volatile Na and a metal-organic framework are given as examples. A dynamical refinement of the structures is possible with data sets requiring a dose of less than 0.15 e-/Ų.

Genetic characterization of Fusarium graminearum and F. culmorum isolates from Turkey by using random-amplified polymorphic DNA.

Five Fusarium graminearum and 12 F. culmorum isolates, primarily pathogenic species of Fusarium head blight, were obtained from naturally infected wheat from various agro-ecological regions of Turkey. Genotyping of the isolates was carried out using random-amplified polymorphic DNA (RAPD). Sixty-five 10-mer oligonucleotide primers were used to amplify the RAPD markers. Among them, 50 primers produced strong and reproducible DNA amplicons. The remaining primers generated either insufficient or no amplification patterns. In total, 1200 fragments were scored, 311 of which were determined to be polymorphic and unique to the isolates. The produced RAPD markers ranged from 0.2 to 5 kb. The mean genetic similarity values of the F. graminearum and F. culmorum isolates were 61.5 and 65%, respectively. The similarity coefficient was 43 to 76.1% among F. graminearum isolates and 49 to 81.1% among F. culmorum isolates. Genetically, the most similar F. graminearum isolates were F6 and F7 (76.1%), which originated from the same agro-ecological region (Sakarya). The most similar F. culmorum isolates were F20 and F21 (81.1%), which were from different geographic regions (Bilecik and UÅYak, respectively). Moreover, interspecific variation between the two species was determined to be 86.3 to 93.3%. Cluster analysis generated two branched groups, each containing isolates of one species, except F13 of F. culmorum. The sequencing of stable and reproducible monomorphic and polymorphic RAPD markers indicated that the Fusarium genome shared high similarity (105-625 bit scores) with the genomes of other organisms as well as with the F. graminearum reference genome.

[Preservative-free triamcinolone versus purified triamcinolone preparations]. / Primär konservierungsmittelfreies Triamcinolon im Vergleich zu aufgereinigten Triamcinolonpräparaten.

BACKGROUND: Intravitreal injections of triamcinolone are not only an important therapeutic tool for a variety of vitreo-retinal disorders, but can also be employed for visualisation of the vitreous during pars plana vitrectomy. Triesence® is a preservative-free triamcinolone suspension that has been approved for visualisation during vitrectomy via intravitreal administration and as intravitreal therapy for certain rare ocular diseases. However, the differences between Triesence® and purified (and thus also preservative-free) triamcinolones such as Volon A® or Kenalog® are not well specified, although the manufacturer of Triesence® advertises the product as "specifically formulated for the eye". METHODS: The publicly available FDA application material and information provided by the manufacturer for Triesence®, Kenalog® and Volon A® were analysed with respect to the differences between Triesence® and older triamcinolone preparations. RESULTS: According to the publicly available FDA documents the approval of Triesence mainly was based on studies that have been conducted with the older triamcinolone preparations Kenalog® or purified Volon A®. Apart from the absence of preservative the differences between Triesence® and the "older" triamcinolone preparation seem marginal. Published experimental or clinical studies in respect to the possible advantages of Triesence® compared to Kenalog® or Volon A® are lacking. Triesence® has been approved for sympathetic ophthalmia, temporal arteriitis, uveitis unresponsive to topical corticosteroids and for enhancing tissue visualisation during vitrectomy. Recently, the manufacturer of Kenalog® added a warning label ("not for intraocular use") on each vial of Kenalog®. The motifs for this re-labelling of Kenalog® remain unclear. CONCLUSION: Apart from the intraoperative use during vitrectomy Triesence® has only been approved for sympathetic ophthalmia, temporal arteriitis, and ocular conditions unresponsive to topical steroids. Consequently, the use of Triesence® like the older triamcinolone preparations (Kenalog® or Volon A®) for diabetic macular oedema, for Irivine-Gass syndrome, for neovascular AMD or after retinal vein occlusion is off-label.

The effects of ranibizumab (Lucentis) on retinal function in isolated perfused vertebrate retina.

BACKGROUND: Intraocular ranibizumab (Lucentis, Novartis, Basel Switzerland) is the primary choice in the treatment of neovascular age-related macular degeneration (AMD). Vascular endothelial growth factor (VEGF) is known to be a survival factor for neuronal cells. Therefore, blockage of all VEGF isoforms by ranibizumab could induce retinal dysfunction. METHODS: Using isolated bovine retinas, the electroretinogram (ERG) was recorded as a transretinal potential using Ag/AgCl electrodes, while the retinas were perfused with an oxygen preincubated nutrient solution. For 45 min, ranibizumab was applied at a concentration of 0.2 mg/ml and alternatively the solvent carrier without the active agent. The ERG was monitored before, during and after exposure. RESULTS: The concentration of 0.2 mg/ml ranibizumab induced a non-significant b-wave reduction of 22.32% after exposure (p = 0.13). For the a-wave amplitude only a reduction of 4% was detected (p = 0.18). The solvent carrier induced no significant reduction of the a- and b-wave amplitudes (p = 0.30 and p = 0.979, respectively). CONCLUSION: In the ex vivo model, the isolated perfused vertebrate retina, ranibizumab has been proven to be a safe compound at the concentrations applied. The stability of the ERG-amplitudes rules out a considerable retinal dysfunction after an injection of up to 1 mg ranibizumab.