Biomedical subjects

R Müller-Velten

Publications and source records attributed to R Müller-Velten.

3 recordsLinked to original sources

PubMed2003

[Photodynamic therapy: extended indication].

OBJECTIVE: Evaluation of efficacy of photodynamic therapy (PDT) for classic choroidal neovascularization (CNV) beyond the common indication. METHODS: A group of 256 patients was treated with photodynamic therapy from January to December 2000. Ten of these patients had a predominantly classic CNV due to angioid streaks (5), parafoveal telangiectasia (2), or chorioretinitis (3). In two patients an idiopathic origin of the CNV was presumed. Another 21 patients showed a juxtafoveal classic membrane (12) or a recurrence after laser photocoagulation (9). Visual acuity was evaluated, also in correlation to age and CNV size. Continuous follow-up of CNV and leakage size was performed with fluorescein angiography. RESULTS: Overall 85% of the patients showed visual stabilization or improvement during an average observation period of 10.5 months. A correlation was found between age and visual improvement favoring younger patients; however, no correlation was found between visual improvement and CNV size. CNV and leakage size decreased moderately over the 9-month follow-up from 1.81/3.45 mm(2) to 1.61/2.60 mm(2). CONCLUSION: PDT shows efficacy for classic choroidal neovascularization beyond the common indication.

Choroidal Neovascularization↗

PubMed2001

The neuroprotective properties of gabapentin-lactam.

BACKGROUND: Gabapentin-lactam (GBP-L) is a derivative of the anti-convulsivant drug gabapentin. In vitro, GBP-L diminished the hypoxia-induced release of the neurotransmitter and excitotoxin glutamate. This effect could be reversed with glibenclamide, indicating that GBP-L acts as an opener of ATP-sensitive potassium channels. In vivo, GBP-L was neuroprotective in a rat model of acute retinal ischemia. In this study we investigated the time- and dose-effect relationship of this neuroprotection. METHODS: In each treatment group (n=9), retinal ischemia was induced in the left eye by pumping air into the anterior chamber to an intraocular pressure of 120 mmHg for 1 h. Two weeks later, neuronal damage in the ganglion cell layer was histologically quantified. Group 1 received vehicle only; group 2 received 75 mg/kg GBP-L i.p. at the beginning of ischemia; groups 3, 4, 5, 6, and 7 received the same dose at 1, 2, 3, 4, and 5 h after onset of reperfusion. Subgroups 5b and 5c received 50 and 25 mg/kg, respectively, 3 h after reperfusion. Each injection was repeated once after 6 h. RESULTS: The proportions of neurons that survived in groups 1 to 7 were 28%, 70%, 59%, 55%, 58%, 45%, and 37%, respectively. The proportions of neurons surviving in groups 5b and 5c were 49% and 39%, respectively. The difference in neuronal survival between group 1 and groups 2, 3, 4, 5, 5b, and 6 was statistically significant. CONCLUSION: GBP-L was neuroprotective in an animal model of acute retinal ischemia, even when given up to 4 h after reperfusion. GBP-L may prove useful in optic neuropathies such as glaucoma.

Animals↗

PubMed2000

[Measuring retinal circulation with the Heidelberg retinal flowmeter: reproducibility of data and no effect of metipranolol in normal probands].

PURPOSE: We wanted to know whether topical Metipranolol has any effect on ocular blood flow. Before starting this investigation using the Heidelberg Retina Flowmeter, we studied the reproducibility of this device. METHOD: Retinal blood flow was determined in 15 healthy volunteers. Altogether, each volunteer was measured 20 times (4 different days with 5 pictures each). Coefficients of variation were calculated for both, the short term fluctuation and the long term fluctuation. After that, the effect of metipranolol was tested in 14 of the 15 volunteers mentioned above. This was done in a randomized, placebo controlled, double masked and crossover designed study. RESULTS: The mean coefficients of variation were 21% for the short term fluctuation and 13% for the long term fluctuation. There was a significant effect of learning, i.e. coefficients of variation decreased with increasing experience of the investigator (MVR). Blood flow values did not differ significantly between metipranolol and placebo. CONCLUSIONS: 1. The reproducibility of blood flow values measured with the Heidelberg Retina flowmeter are sufficient, at least if the device is used in clinical studies. When performing those studies, the learning curve of the investigator should be taken into account. 2. The topical application of metipranolol does not alter the retinal blood flow in healthy volunteers.

Adult↗