A. Nestler

A new instrument for the quantification of macular pigment density: first results in patients with AMD and healthy subjects.

Abstract Background. There is growing evidence that the development of age-related macular degeneration (AMD) is related to oxidative damage. This makes macular pigment (MP) an interesting target for research, as antioxidative quality is related to MP. As studies have shown that MP density (MPD) can be increased by dietary supplementation, MP may also offer a therapeutic or preventive approach to AMD. Methods. Using scanning laser techniques, we quantified MPD in healthy subjects and patients with dry AMD. We introduce a modified scanning laser ophthalmoscope (SLO) which includes several advantages for the use in the clinical routine compared to the standard SLO. Results. We examined 10 healthy subjects without ocular pathology and 10 patients with dry AMD (geographic atrophy). Eyes of patients with AMD had a significantly lower MPD (mean value 0.094±0.022 density units, DU) than healthy eyes (mean value 0.184±0.023 DU). Conclusions. It is possible to quantify MPD using a scanning laser ophthalmoscope in a clinical setting. The modified SLO offers several improvements with regard to the special requirements of the clinical situation. Using the new instrument, we were able to detect differences in MPD between patients with dry AMD and young healthy subjects. Further studies are needed to evaluate the reliability and reproducibility of the method.

Use of Piritramide for Analgesia and Sedation during Peribulbar Nerve Block for Cataract Surgery

Purpose: To investigate the effects of pre-block analgesia and sedation using piritramide on haemodynamic stability, endocrine stress response and patients’ pain perception. Methods: In a randomized, single-blinded, placebo-controlled study, 60 patients having cataract surgery with peribulbar block were randomly assigned into two groups: group A (n = 30) received 0.05 mg/kg piritramide (Dipidolor®) intravenously; group B received normal saline intravenously prior to peribulbar block. Mean arterial pressure, heart rate, respiratory rate and pulse oximetry were recorded perioperatively. Pain from peribulbar block was assessed using a verbal analogue scale. Urinary excretion of vanillylmandelic acid was measured to assess the endocrine stress response. Using a questionnaire, patients assessed their anxiety and back pain before and during surgery. Results: Mean arterial pressure remained near baseline in group A. In group B, a significant increase in mean arterial pressure after peribulbar block was found (p < 0.001). In addition, a significant increase in urinary excretion of vanillylmandelic acid was found in group B (p = 0.013). Pain scores (p < 0.001), anxiety before nerve block (p = 0.02) and during surgery (p < 0.001) and back pain (p = 0.003) were significantly lower in group A. Conclusion: The presented study suggests that using piritramide for analgesia and sedation prior to peribulbar block produces haemodynamic stability and reduces pain perception and endocrine stress response.

On-block UV light polymerization of LR gold-embedded flat-mounted tissue using low temperature modules

A problem associated with low temperature embedding is due to the fact that suitable resins have to be polymerized under oxygen-free atmosphere, thus making the complete filling and tight sealing of vials or capsules essential. Particularly with thin tissue sections or retinal flat-mounts it is rather difficult to obtain flat-embedded specimens under these conditions. To overcome this problem, we have designed a low temperature module (LTM) that allows the polymerization of flat tissue probes on faced resin blocks using UV light, thus instantly creating ready specimens with an almost planar surface. To test the device, vibratome sections of the rat superior colliculus were embedded in LR Gold and UV-cured in LTMs. Electron microscopy revealed a good preservation of the fine structure. The new UV light polymerization technique proved to be highly suitable to obtain ultrathin sections being cut parallel to the surface of the embedded material, an advantageous feature for applications which necessitate the examination of specifically oriented or laminated structures. Detailed and dimensioned drawings of the LTM can be downloaded as a PDF file at: http://www.uni-leipzig.de/-vetana.