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Biomedical subjects

M Völcker

Publications and source records attributed to M Völcker.

5 recordsLinked to original sources
PubMed2006

[Early antiexudative response--OCT monitoring after intravitreal bevacizumab injection].

VEGF is more potent than histamine by a factor of 50,000 for inducing increased vessel permeability. Already in the first few minutes, hydraulic conductivity and diffusive permeability are significantly increased, followed by a longer-lasting, marked leakage over 20 h. Specific inhibition of the angiogenic, vasoactive, and permeability-inducing protein VEGF is now possible by new drugs, one of which is the first available (off-label) treatment in Germany for routine clinical use (Avastin). Retinal edema is composed of increased outflow of water and low molecular substances in the interstitial environment and is an important determinate of functional development in different ocular diseases. First experiences with the anti-hyperpermeability effect show early response and high potential in pathologic leakage. Future examinations have to assess when a permanent benefit can be achieved in respect to the other antiproliferative capabilities of the drug.

Angiogenesis Inhibitors↗
PubMed1998

Fluorescence cross-correlation: a new concept for polymerase chain reaction.

In this article we present a new concept for the detection of any specifically amplified target DNA sequences in multiple polymerase chain reactions (PCR) based on fluorescence correlation spectroscopy (FCS). The accumulation of double-stranded target DNA is monitored by the cross-correlated fluorescence signals provided by two amplification primers which are 5'-tagged with two different kinds of fluorophores (Rhodamine-Green and Cy5). Only the amplified target DNA sequence carrying both primers is observed. Its signal emerges from the background of non-incorporated or non-specifically incorporated primers. Down to 10-25 initial copy numbers of the template in the PCR compartment DNA can presently be detected. No external or internal standards are required for determining the size and the amplified copy number of specific DNA. The PCR amplification process is started with all ingredients in a single compartment (e.g. of a microtiter plate), in which amplification and measurement are performed. This eliminates the need for post-PCR purification steps. The homogeneous one-tube approach does not depend on fluorescence energy transfer between the fluorogenic dyes. Thus, it does not interfere with the enzymatic amplification reaction of PCR and allows the continued use of different conditions for amplifying DNA. The results exemplified by PCR-amplified 217-bp and 389-bp target DNA sequences demonstrate that the analysis based on two-color fluorescence cross-correlation is a powerful method for simplifying the identification of targets in PCR for medical use. For this purpose, an instrument optimized for two-color excitation and detection of two-color emission has been developed, incorporating the principle of confocal arrangement.

Base Sequence↗