Annika Haak

Ruhr-Universität Bochum | RUB · Central Unit for Ion beams and Radio nuclides

Biological samples for microscopical imaging are predominantly fixed with aldehydes such as paraformaldehyde (PFA), glutaraldehyde, or combinations of these. These fixatives cross link proteins with varying effectiveness, depending on the concentration, incubation time, temperature, and pH value. This can alter the cytoskeletal morphology, reduce m...

Biological samples prepared for microscopical investigations often undergo chemical fixation to preserve the sample. Most commonly aldehydes such as paraformaldehyde (PFA) or glutaraldehyde (GA) are used. However, these aldehydes have been known to disrupt cytoskeletal morphology, membrane integrity or epitopes. In order to conduct reproducible and...

Chemical fixation with aldehydes such as paraformaldehyde (PFA) is one of the most common approaches when preparing biological samples for microscopy. However, aldehyde treatment can drastically change the sample‘s morphology. An alternative method, which has been shown to better preserve the native structure of biological samples[1] , is cryofixat...

When preparing biological samples for microscopy, chemical fixation with aldehydes is one of the most common approaches. However, aldehyde treatment can drastically change cytoskeletal morphology, damage membrane integrity, or hinder epitope accessibility. Thus, it is advisable to switch from chemical fixation to cryofixation whenever possible as c...

Oligodendrocytes are responsible for axon myelination in the nervous system thereby enabling faster action potential propagation over long distances in neurons. Their progenitors, oligodendrocyte progenitor cells (OPCs), migrate from the ventricular zone of the brain and spinal cord towards their target cells located in all parts of the nervous sys...

Scientific studies need to be reproducible to yield reliable results. Replicability of studies quantifying cell numbers in images may suffer from biases and uncertainties introduced by cell identification. The aim of our investigation is to analyze the variance of cell counting results by comparing cell counts obtained from different individuals an...

The development of diffraction-unlimited fluorescence microscopy has paved the way for a detailed understanding of cellular dynamics since live-cell investigations with resolutions below 100 nm have become available. This allows studying labelled specimen such as proteins and their distribution within a cell at a new level of detail. However, exami...

Cell culture studies offer the unique possibility to investigate the influence of pharmacological treatments with quantified dosages applied for defined time durations on survival, morphological maturation, protein expression and function as well as the mutual interaction of various cell types. Cultures obtained from postnatal rat brain contain a s...

Primary cell cultures are preferable to neuronal cell lines because they preserve the receptor expression and signal transduction cascades and thus the developmental potential of native neurons and glial cells. One of the disadvantages of experiments involving primary cultures is the limited availability, limited life span and necessity to obtain c...

Brain inflammation may lead to both dizziness as well as epileptiform neuronal hyperactivity. In order to find out, whether inflammatory processes may lead to changes in neuronal excitability we previously investigated whether the activation of microglia by lipopolysaccharides (LPS) could influence Na+ current density in postnatal rat hippocampal n...