Growth factor restriction impedes progression of wound healing following cataract surgery: identification of VEGF as a putative therapeutic target

Secondary visual loss occurs in millions of patients due to a wound-healing response, known as posterior capsule opacification (PCO), following cataract surgery. An intraocular lens (IOL) is implanted into residual lens tissue, known as the capsular bag, following cataract removal. Standard IOLs allow the anterior and posterior capsules to become physically connected. This places pressure on the IOL and improves contact with the underlying posterior capsule. New open bag IOL designs separate the anterior capsule and posterior capsules and further reduce PCO incidence. It is hypothesised that this results from reduced cytokine availability due to greater irrigation of the bag. We therefore explored the role of growth factor restriction on PCO using human lens cell and tissue culture models. We demonstrate that cytokine dilution, by increasing medium volume, significantly reduced cell coverage in both closed and open capsular bag models. This coincided with reduced cell density and myofibroblast formation. A screen of 27 cytokines identified nine candidates whose expression profile correlated with growth. In particular, VEGF was found to regulate cell survival, growth and myofibroblast formation. VEGF provides a therapeutic target to further manage PCO development and will yield best results when used in conjunction with open bag IOL designs

Integration eines Kanalemulators in den Labormessplatz für die Bewertung von industriellen Funksystemen

Diese Arbeit befasst sich mit der Inbetriebnahme und Integration eines Kanalemulators in einen Versuchsaufbau zur Bewertung von industriellen Funksystemen. Hierzu wurde der Kanalemulator mithilfe definierter Kenngrößencharakterisiert, die Grenzen des Einsatzbereiches erfasst und darauf folgend einige Performancekenngrößen eines Funksystems mithilfe des Labormessplatzes gemessen.The bachelor thesis addresses the integration of a channel emulator into a test assembly for benchmarking industrial wireless systems. The channel emulator has been evaluated and an operating range has been defined. A few parameters of a wireless system were measured

A review of the surgical options for the correction of presbyopia

Presbyopia is an age-related eye condition where one of the signs is the reduction in the amplitude of accommodation, resulting in the loss of ability to change the eye's focus from far to near. It is the most common age-related ailments affecting everyone around their mid-40s. Methods for the correction of presbyopia include contact lens and spectacle options but the surgical correction of presbyopia still remains a significant challenge for refractive surgeons. Surgical strategies for dealing with presbyopia may be extraocular (corneal or scleral) or intraocular (removal and replacement of the crystalline lens or some type of treatment on the crystalline lens itself). There are however a number of limitations and considerations that have limited the widespread acceptance of surgical correction of presbyopia. Each surgical strategy presents its own unique set of advantages and disadvantages. For example, lens removal and replacement with an intraocular lens may not be preferable in a young patient with presbyopia without a refractive error. Similarly treatment on the crystalline lens may not be a suitable choice for a patient with early signs of cataract. This article is a review of the options available and those that are in development stages and are likely to be available in the near future for the surgical correction of presbyopia

Posterior capsule opacification: What's in the bag?

Cataract, a clouding of the lens, is the most common cause of blindness in the world. It has a marked impact on the wellbeing and productivity of individuals and has a major economic impact on healthcare providers. The only means of treating cataract is by surgical intervention. A modern cataract operation generates a capsular bag, which comprises a proportion of the anterior capsule and the entire posterior capsule. The bag remains in situ, partitions the aqueous and vitreous humours, and in the majority of cases, houses an intraocular lens (IOL). The production of a capsular bag following surgery permits a free passage of light along the visual axis through the transparent intraocular lens and thin acellular posterior capsule. Lens epithelial cells, however, remain attached to the anterior capsule, and in response to surgical trauma initiate a wound-healing response that ultimately leads to light scatter and a reduction in visual quality known as posterior capsule opacification (PCO). There are two commonly-described forms of PCO: fibrotic and regenerative. Fibrotic PCO follows classically defined fibrotic processes, namely hyperproliferation, matrix contraction, matrix deposition and epithelial cell trans-differentiation to a myofibroblast phenotype. Regenerative PCO is defined by lens fibre cell differentiation events that give rise to Soemmerring's ring and Elschnig's pearls and becomes evident at a later stage than the fibrotic form. Both fibrotic and regenerative forms of PCO contribute to a reduction in visual quality in patients. This review will highlight the wealth of tools available for PCO research, provide insight into our current knowledge of PCO and discuss putative management of PCO from IOL design to pharmacological interventions

Erstellung von Interferenzprofilen mithilfe einer Software Defined Radio Plattform

The experimental research on wireless technologies demands full access to all network layers. Pre-built hardware solutions offer, if any, only limited access to these layers. Alternative choices are software defined radios, which feature RF-hardware and reprogrammable components for a wide array of applications. In this thesis, the software defined radio USRP X310 from Ettus is used to emulate the occupation of the wireless transmission medium by communication systems like those specified by IEEE 802.11. Its ability to influence communication systems in a defined manner has been examined. Therefore, the occupation in frequency, time and transmission power has been tested and compared to the performance of a vector signal generator, which features designated hardware. The used hardware in the USRP X310 is designed for a wider range of applications. In comparison to the designated and more expensive hardware of the vector signal generator, this range comes with generally poorer RF-properties. A few aspects to regardare shown in this master thesis

Anterior chamber measurements using Pentacam rotating Scheimpflug camera.

PURPOSE: To investigate the mean values and standard deviations according to age, reliability, and correlation between different parameters of anterior chamber measurements using the Pentacam rotating Scheimpflug camera. SETTING: Heidelberg IOL and Refractive Surgery Research Group, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. METHODS: This prospective clinical study comprised 76 healthy volunteers (mean age 46.6 years +/- 16.8 [SD]). Three consecutive measurements were made of only 1 eye and anterior chamber depth (ACD), mean and minimum anterior chamber angle (ACA), and anterior chamber volume (ACV) were evaluated. RESULTS: Mean ACD was 2.93 +/- 0.36 mm, mean ACA was 34.81 +/- 5.05 degrees, minimum ACA was 29.99 +/- 5.53 degrees, and mean ACV was 160.3 +/- 36.81 mm3. Increasing age was associated with reduced ACD and ACV; however, mean and minimum ACAs were lowest in patients aged 40 to 59 years. Excellent correlation was found between ACD and ACV (R = 0.92). Anterior chamber depth and mean ACA correlated only moderately (R = 0.65). The correlation coefficient between ACD and minimum ACA was smaller (R = 0.58). There was no correlation between ACV and ACA (R = 0.37). Minor standard deviations were noted (ACD 0.02 +/- 0.02 mm, mean ACA 1.12 +/- 0.94 degrees, minimum ACA 2.04 +/- 2.67 degrees, and ACV 2.48 +/- 1.65 mm3). CONCLUSIONS: Using the Pentacam, it was possible to examine different parameters of the anterior chamber within a short period and with good reliability. The evaluation of the ACA in different positions can help to classify the potential risk for angle-closure glaucoma