Martin Hermel

Sterilization and preservation influence the biophysical properties of human amnion grafts

The introduction of amniotic membrane (AM) transplantation in ophthalmic surgery holds great promise and in many clinical situations it offers an alternative to existing management options. The purpose of this study was to examine the influence of established sterilization and preservation procedures on biophysical and histological properties of AM grafts. Amnion was sterilized by peracetic acid/ethanol sterilization [PES] and preserved by air-drying (sterile laminar flow) [AD] or in glycerol [GLYC]. Unsterilized AM were preserved at -80 degrees C [-80 degrees C] and served as an experimental control. Amnion allografts were characterized by the determination of their thickness, moisture vapour permeability (MVP), oxygen permeability (OPERM), tensile strength and sulphur content. Immunostaining for tissue-specific and basement membrane-related proteins was performed. Differences in biophysical parameters were found between the unsterilized allografts and the sterilized, air-dried or glycerol-preserved allografts. [PES/AD] showed the highest MVP and OPERM, the highest tensile strength and the lowest sulphur content and thickness. [PES/GLYC] exhibited the lowest OPERM and the highest thickness compared to [-80 degrees C] and [PES/AD]. Collagen types V and VII were preserved the best in the control group. Sterilization and preservation affect biophysical properties important for the use of AM as allogenic grafts. It has to be determined if any change, as noted, has a clinical impact.

Efficacy of Plasmin, Microplasmin, and Streptokinase-Plasmin Complex for the In Vitro Degradation of Fibronectin and Laminin- Implications for Vitreoretinal Surgery

Purpose: Plasmin enzyme generates vitreoretinal separation by degradation of laminin and fibronectin in the vitreoretinal interface. It can be activated from plasminogen by urokinase, tissue plasminogen activator, or by formation of a 1:1 complex with streptokinase. The latter is then converted into a streptokinase-plasmin-complex (SK-P), which displays fibrinolytic activity and can generate free plasmin by proteolysis of plasminogen. We compared the efficacy of SK-P, SK-P activated plasmin, urokinase activated plasmin (UK-P), and microplasmin, a truncated form of plasmin, in cleaving laminin and fibronectin. Methods: Streptokinase (SK) was added to human plasminogen in molar ratios between 1:100 and 2:1, generating SK-P at ratios > 1:1, and mixtures of SK-P and free plasmin (SK-P/plasmin) at lower ratios. SK-PL, SK-P/plasmin, UK-P, and microplasmin were added to laminin and fibronectin, incubated at 37°C for 30 min–22 hr and processed for SDS-PAGE. Results: Proteolysis using SK-activated plasminogen increased when the SK/plasminogen ratio was decreased, generating increasing amounts of free plasmin. Microplasmin and urokinase-activated plasmin displayed similar proteolysis of both laminin and fibronectin as SK/plasminogen at ratios of 1:10 or lower. Conclusion: The mode of plasminogen activation influences the efficacy of proteolysis for laminin and fibronectin and should be considered when plasmin is used in vitreoretinal surgery.

Changing Indications in Penetrating Keratoplasty: A Systematic Review of 34 Years of Global Reporting.

Background Penetrating keratoplasty (PK) ranks among the oldest and most common kinds of human tissue transplantation. Based on the hypothesis that reported indications for PK significantly vary between global regions and over time, the present systematic review aimed to provide a thorough overview of global PK indications as reported in peer-reviewed manuscripts. Methods A literature search of PubMed and MEDLINE was conducted to retrieve articles published from January 1980 to May 2014. Indications for PK within 7 global regions were compared using a modified classification system for PK indications and analyzed via multivariate regression. Results A total of 141 publications from 37 countries were included, recording 180 865 PK cases. Postcataract surgery edema was the predominant indication in North America (28.0%) and ranked second in Europe (20.6%), Australia (21.1%), the Middle East (13.6%), Asia (15.5%), and South America (18.6%). Keratoconus was the leading indication in Europe (24.2%), Australia (33.2%), the Middle East (32.8%), Africa (32.4%), and South America (22.8%). It ranked third in North America (14.2%). Keratitis was the primary indication in Asia (32.3%). Fuchs endothelial corneal dystrophy was the fourth most common indication in North America (12.9%) and Europe (10.2%) and fifth in South America (3.8%). Multivariate analysis supported these results and revealed individual regional changes over time. Conclusions Systematic analysis reveals characteristic chronological and regional differences in reported global PK indications. Leading reported indications for PK between 1980 and 2014 were keratoconus (Europe, Australia, the Middle East, Africa, and South America), pseudophakic bullous keratopathy/aphakic bullous keratopathy (North America), and keratitis (Asia).

New treatment option for adult-onset limbal xanthogranuloma.

Purpose: The purposes of this study are to report a case of adult-onset juvenile xanthogranuloma and suggest a new treatment option. Methods: A 35-year-old man presented with an isolated mass of the limbus. Biopsy revealed a histiocytic tumor with Toutons giant cells staining positive for CD68 and S-100 but negative for CD1a, consistent with JXG. Two intratumoral injections of triamcinolone acetonide 6 weeks apart were performed. The main outcome measure was 6-months follow up clinically and by ultrasound biomicroscopy. Results: The lesion regressed, and corneal thickness returned to normal 3 months after the first injection. An increase in intraocular pressure required topical treatment. No recurrence was seen throughout follow up. Conclusion: Limbal juvenile xanthogranuloma can be successfully treated with intralesional triamcinolone acetonide, thus avoiding a lamellar keratectomy approach.

Inhibitory effect of ascorbic acid on human retinal pigment epithelial cell proliferation compared to cytostatic drugs - influence of histamine

Surgery or trauma to the posterior segment of the eye frequently leads to misplacement of retinal pigment epithelial (RPE) cells into the vitreous cavity, generating proliferative membranes and seriously threatening vision. Ascorbic acid has been shown to elicit antiproliferative effects on fibroblasts of several species, bovine lens epithelial and guinea pig vascular smooth muscle cells via different mechanisms [1]. As this compound is abundant in ocular fluids of healthy eyes, whereas reduced levels were found in eyes with proliferative diseases [2], it might play a role in the control of intraocular cell proliferation. Histamine elicited receptorInflamm. res. 50, Supplement 2 (2001) S93–S95 1023-3830/01/02S93-03

Bitte um Einverständnis in eine Hornhautspende

1.50+0.20/0

Severe ulcerative keratitis in ocular cowpox infection.

INTRODUCTION Because of the gap between the high need for cornea tissue for transplantation and the current lower numbers of donors, there is high pressure to succeed in telephone calls to relatives of deceased for obtaining consent. Besides the attempt to increase the rate of donors, these telephone calls should be gentle for relatives and not overstrain professionals. This study assesses the need and expectations of physicians towards communication training in preparation for their task. METHODS In September-October 2009 a needs assessment for communication training among physicians who currently work or have worked for the eye bank took place. Personal data were recorded and their estimate of the perceived burden as well as needs and potential benefits from a specific communication training for obtaining consent for cornea donation by telephone were assessed using numeric rating scales between 1 (minimum) and 10 (maximum). Results were expressed as mean and range. RESULTS The participants felt only moderately prepared for the task regarding information content, their emotions and personal convictions. They considered a specific training to be highly meaningful, necessary and helpful. Their highest burden during telephone calls previously experienced was documented as 8.4 and the average burden as 6.3. Accordingly, their willingness to continue working at an eye bank after their rotation was moderate. DISCUSSION Physicians involved in obtaining consent for cornea donation by telephone feel highly stressed and only moderately prepared for fulfilling the task both for the information content and on the emotional level. Accordingly, specific communication training is perceived as highly meaningful, necessary and helpful. An educational program was developed to meet the needs and expectations of physicians.ZusammenfassungHintergrundDurch den hohen Bedarf und der deutlich geringeren Verfügbarkeit von Hornhäuten des Auges besteht eine große Hoffnung auf das Gelingen ärztlicher Akquisegespräche mit Angehörigen zum Einverständnis in eine Gewebespende. Neben der Steigerung des Erfolgs in der Spendergewinnung sollen Akquisegespräche schützend für Angehörige verlaufen und die Arbeitsbelastung des Fachpersonals gering gehalten werden. Diese Arbeit erfasst den Bedarf und Erwartungen an ein Kommunikationstraining zur Vorbereitung auf die Akquisetätigkeit.MethodeIm September und Oktober 2009 wurde unter allen Akquiseärzten, die in der Hornhautbank arbeiten bzw. gearbeitet haben, eine Bedarfanalyse für ein Kommunikationstraining vorgenommen. Auf 10-stufigen numerischen Rangskalen wurde das Ausmaß der fachlichen, emotionalen und persönlichen Vorbereitung, das Ausmaß der Einschätzung eines Kommunikationstrainings als sinnvoll, notwendig und hilfreich sowie die durchschnittliche und höchste Belastung und Bereitschaft zur Ausübung der Akquise erfragt.ErgebnisseDie Studienteilnehmer fühlten sich fachlich, emotional und in ihrer persönlichen Überzeugung nur mittelmäßig auf die Tätigkeit vorbereitet und erachteten ein Kommunikationstraining für in hohem Maß sinnvoll, notwendig und hilfreich. Bei mittlerer durchschnittlicher Arbeitsbelastung mit kurzfristigen Hochbelastungsphasen bestand nur eine moderate Bereitschaft zur weiteren Ausführung dieser Tätigkeit.DiskussionDurch klare Hinweise auf eine nicht als ausreichend empfundene Vorbereitung auf die Akquisetätigkeit und als hoch empfundene Arbeitsbelastung wurde ein Kommunikationsseminar mit einem spezifischen Training der Akquisetelefonate entwickelt. Dieses Training entspricht bedarfsgemäß sowohl den Wünschen und Erwartungen des ärztlichen Personals als auch den am ehesten beeinflussbaren Variablen im Hinblick auf die Erfolgsquote bei der Spendenakquise.AbstractIntroductionBecause of the gap between the high need for cornea tissue for transplantation and the current lower numbers of donors, there is high pressure to succeed in telephone calls to relatives of deceased for obtaining consent. Besides the attempt to increase the rate of donors, these telephone calls should be gentle for relatives and not overstrain professionals. This study assesses the need and expectations of physicians towards communication training in preparation for their task.MethodsIn September–October 2009 a needs assessment for communication training among physicians who currently work or have worked for the eye bank took place. Personal data were recorded and their estimate of the perceived burden as well as needs and potential benefits from a specific communication training for obtaining consent for cornea donation by telephone were assessed using numeric rating scales between 1 (minimum) and 10 (maximum). Results were expressed as mean and range.ResultsThe participants felt only moderately prepared for the task regarding information content, their emotions and personal convictions. They considered a specific training to be highly meaningful, necessary and helpful. Their highest burden during telephone calls previously experienced was documented as 8.4 and the average burden as 6.3. Accordingly, their willingness to continue working at an eye bank after their rotation was moderate.DiscussionPhysicians involved in obtaining consent for cornea donation by telephone feel highly stressed and only moderately prepared for fulfilling the task both for the information content and on the emotional level. Accordingly, specific communication training is perceived as highly meaningful, necessary and helpful. An educational program was developed to meet the needs and expectations of physicians.

Role of the Endothelial Layer in the Deswelling Process of Organ-Cultured Human Corneas Before Transplantation.

Dear Editor, In February 2009, a 40-year-old woman attended the Dept. of Ophthalmology of the RWTH Aachen University with red eye symptoms on the right side. Previous dermatological investigation revealed a cowpox skin lesion under the collarbone 1 week after exposure to a pet rat. The transmission via smear infection from the pet rat after multiple exposures was proven. Six days after the occurrence of the dermatological symptoms, ophthalmic examination was performed and revealed a phlycten-like conjunctival lesion with mild conjunctival injection. Despite topical anti-inflammatory and antibiotic therapy, conjunctival injection was progressive, with increasing chemosis of the nasal conjunctiva. Four weeks after the first ophthalmic examination, the cornea showed progressive infiltration. A swab for bacteriological examination showed an infection with Staphylococcus aureus. The corneal infiltrate resolved under systemic and topical antibiotic therapy in the following weeks, but the cornea showed progressive erosion and limbal ulceration tending to perforate (Fig. 1). A corneal swab was analysed for poxviruses by quantitative real-time PCR and sequencing of the entire open reading frame of the haemagglutinin gene (924 bp, Accession number JF330118) to confirm the diagnosis of ocular cowpox infection. During follow-up, the anterior chamber showed a slight inflammation with small endothelial corneal precipitates. To prevent further limbal ulceration of the cornea, in-house-produced kallikrein-inhibitory eye drops (i.e., aprotinin) were added. Four months after the appearance of ocular symptoms, another specimen of the cornea was taken, and the PCR for cowpox virus was negative. Then, topical steroid eye drops were added to suppress the immunological limbal and anterior chamber response. The following months presented severe persistent subtotal corneal erosion due to limbal stem cell insufficiency. Anterior chamber inflammation and corneal ulceration was under control (Fig. 2). Human cases of cowpox virus infections are commonly described after transmission from domestic cats and directly from rats [1]. A specific antiviral cowpox therapy is not known. There are some reports of the use of cidofovir, an inhibitor of viral DNA-polymerase, in severe systemic cowpox infections [2]. Cowpox infection typically is a selflimiting disease, resulting in scarring of the skin lesions. In 2008, a cluster of cowpox virus infections in humans was reported in Northern and Southern Germany [3, 4], being transmitted by pet rats. The authors assumed a potential further increase in infection rates in the future. The first case report of ocular cowpox infection in 1987 by Hall and Stevens referred to a 28-year-old veterinary

Conjunctival and intraocular swabs for the microbiological assessment of donor corneas

Purpose: Before corneal transplant surgery, a deswelling process of organ-cultured corneas is required. This study compares the deswelling kinetics of corneas with an intact endothelial cell layer and disrupted or removed endothelium by measuring central corneal thickness (CCT) over time using anterior segment spectral domain optical coherence tomography. Methods: Ten donor pairs were cultured in organ culture. The right and left corneas were alternately assigned to one of 2 deswelling groups. Deswelling in the first group [endothelial group (EG)] was induced using a medium with dextran 5%. Corneas of the second group [nonendothelial group (NEG)] were deprived of their endothelial cell layer by trypsinization and were then placed in the same deswelling medium. CCT (mean ± SD) was measured by anterior segment spectral domain optical coherence tomography before deswelling (0 hours) and after 1, 2, 3, 6, 12, 24, 48, 72, and 144 hours. Deswelling kinetics was analyzed through the nonlinear platform in SAS/JMP11 Pro. Results: Before deswelling, CCT was 1071.0 &mgr;m (±129.6 &mgr;m) and 1133.8 &mgr;m (±124.3 &mgr;m) in the EG and NEG, respectively. Minimum corneal thickness was obtained after 24 hours in the EG (531.9 ± 47.5 &mgr;m) and 6 hours in the NEG (645 ± 81.2 &mgr;m). CCT was significantly (P < 0.01) higher in the NEG than EG after more than 6 hours. Conclusions: Corneal dehydration after organ culture seems to be a multifactorial process, which not only depends on osmotic effects of the deswelling compound but also requires the presence of an intact endothelial cell layer.

The Role of Specifically Tailored Communication Training Among Factors Influencing Consent for Cornea Donation Requested Via Telephone.

In this study, we investigated the associations between conjunctival (co) and intraocular (io) swabs and their implications for the contamination rates of organ‐cultured corneas.