Elmar Willbold

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Müller cells are astrocyte-like radial glia cells which are formed exclusively in the retina. Here we present evidence that Müller cells are crucially involved in the development of the retina's architecture and circuitry. There is increasing evidence that Müller cells are present from the very early beginning of retinogenesis. We postulate the "gradual(More)
The reaggregate approach involves the regeneration of histotypical three-dimensional spheres from dispersed cells of a given tissue in suspension culture. Reaggregated spheres are used as tumour, genetic, toxicological, biohybrid and neurosphere models, and often replace animal experimentation. A particularly instructive example is the use of reaggregation(More)
It is well established that embryonic stem (ES) cells can differentiate into functional cardiomyocytes in vitro. ES-derived cardiomyocytes could be used for pharmaceutical and therapeutic applications, provided that they can be generated in sufficient quantity and with sufficient purity. To enable large-scale culture of ES-derived cells, we have developed a(More)
BACKGROUND The recent success in the derivation of differentiated cell types from stem cells has raised prospects for the application of regenerative cell therapy. In particular, embryonic stem cells are attractive sources for cell transplantation, due to their immortality and rapid growth. These cells, however, also possess tumorigenic properties, which(More)
Only two out of four major acetylcholinesterase (AChE) subbands in the inner plexiform layer (IPL) of vertebrate retinae correspond to sites of cholinergic synaptic transmission, as has been shown by the co-distribution of AChE and choline acetyltransferase (ChAT) staining. The function and molecular identity of AChE in non-cholinergic subbands is unknown.(More)
A central function of chicken photoreceptors is the rhythmic synthesis of the neurohormone melatonin; however, it is unclear how they can achieve--already before hatching (i.e. without light exposure)--a circadian pacemaker system. Here we studied melatonin synthesis and secretion in rosetted spheroids, which are de novo histotypic spheres, re-aggregated(More)
The capacities of retinal and pigmented cells to regenerate histotypic in-vitro-retinae (IVR) in rotary culture were investigated by dividing the eye cups of 6-day-old chicken embryos into a central and a peripheral part; they were cut along the ora serrata, and the retinal and the pigmented constituents of both parts were isolated. The 4 dissociated cell(More)
The phylo- and ontogenetically related enzymes butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) are expressed consecutively at the onset of avian neuronal differentiation. In order to investigate their possible co-regulation, we have studied the effect of highly selective inhibitors on each of the cholinesterases with respect to their expression(More)
During chicken neurogenesis, the sequential expression of butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) between final cell proliferation and differentiation is functionally not understood. Recently, cholinesterases have been shown to regulate neurite growth in vitro. Here, we investigated the effects of inhibition of BChE on laminar(More)