Amyloid precursor protein of Alzheimer's disease: evidence for a stable, full-length, trans-membrane pool in primary neuronal cultures.

We and colleagues have shown that the amyloid protein precursor of Alzheimer's disease (APP) is distributed along the surface of neurites of fixed but nonpermeabilized neurons in primary culture in a segmental pattern, which shows colocalization with some markers of adhesion patches. This is in contrast to the diffuse pattern of immunoreactivity seen after permeabilization. We have also recently demonstrated that the APP in these surface patches is likely to be integral to the membrane rather than secreted and re-adsorbed, based on alkali stripping experiments and on soluble APP adsorption experiments.

Structural comparison of fibroblast growth factor-specific heparan sulfates derived from a growing or differentiating neuroepithelial cell line.

Heparan sulfate (HS) glycosaminoglycans are essential modulators of fibroblast growth factor (FGF) activity both in vivo and in vitro, and appear to act by cross-linking particular forms of FGF to appropriate FGF receptors. We have recently isolated and characterized two separate HS pools derived from immortalized embryonic day 10 mouse neuroepithelial 2.3D cells: one from cells in log growth phase, which greatly potentiates the activity of FGF-2, and the other from cells undergoing contact-inhibition and differentiation, which preferentially activates FGF-1.

Structural modification of fibroblast growth factor-binding heparan sulfate at a determinative stage of neural development.

Heparan sulfate (HS) glycosaminoglycans are essential modulators of fibroblast growth factor (FGF) activity and appear to act by coupling particular forms of FGF to appropriate FGF receptors. During neural development, one particular HS proteoglycan is able to rapidly switch its potentiating activity from FGF-2, as neural precursor cell proliferation occurs, to FGF-1, as neuronal differentiation occurs. Using various analytical techniques, including chemical and enzymatic cleavage, low pressure chromatography, and strong anion-exchange high performance liquid chromatography, we have analyzed the different HSs expressed during these crucial developmental stages.

Essential role of heparan sulfates in axon navigation and targeting in the developing visual system.

Heparan sulfate (HS) is abundant in the developing brain and is a required co-factor for many types of fibroblast growth factor (FGF) signaling in vitro. We report that some HSs, when added exogenously to the developing Xenopus optic pathway, severely disrupt target recognition causing axons from the retina to bypass their primary target, the optic tectum. Significantly, HS sidechains from a neuroepithelial perlecan variant that preferentially bind FGF-2, HS(FGF-2), cause aberrant targeting, whereas those that preferentially bind FGF-1 do not.

Videokeratography database of normal human corneas.

Aim: To form a database of videokeratography patterns and quantitative indices describing normal human corneas using the absolute scale.

Methods: Both eyes of 195 normal subjects were examined with a TMS-1 videokeratoscope. Videokeratographs were divided into 10 categories based on a classification scheme devised from the absolute scale and analysed with 10 quantitative indices devised to describe phenotypic features of keratoconus videokeratographs.

Heparan sulfates mediate the binding of basic fibroblast growth factor to a specific receptor on neural precursor cells.

Heparan sulfate proteoglycans are thought to be obligatory for receptor binding and subsequent mitogenic activity of basic fibroblast growth factor (FGF-2). In a previous study (Nurcombe V., Ford, M.