Biomedical subjects

S Henke-Fahle

Publications and source records attributed to S Henke-Fahle.

22 records · Page 2Linked to original sources

PubMed1986

Brain induces the expression of an early cell surface marker for blood-brain barrier-specific endothelium.

Capillaries derived from the perineural vascular plexus invade brain tissue early in embryonic development. Considerably later they differentiate into blood-brain barrier (BBB)-forming blood vessels. In the chick, the BBB as defined by impermeability for the protein horseradish peroxidase develops around embryonic day 13. We have previously found that brain endothelial cells start to express a number of proteins at around the same time, suggesting that these proteins play a role in BBB function. Here we describe a 74 kd protein defined by the monoclonal antibody HT7 that is expressed on the surface of chick embryonic blood cells and brain endothelial but on no other endothelial cells. This protein is not detectable on early embryonic brain endothelium, but is expressed by these cells on embryonic day 10. It is absent in choroid plexus endothelial cells which represent permeable fenestrated endothelial cells. The antigen is expressed on choroid plexus epithelium which is the site of the blood-cerebrospinal fluid barrier. Since it is also found in basolateral membranes of kidney tubules, it may be involved in specific carrier mechanisms. Embryonic mouse brain tissue transplanted on the chick chorio-allantoic membrane induces the expression of this antigen on endothelial cells derived from the chorio-allantois. Brain tissue can therefore induce in endothelial cells in vivo the expression of a molecule characteristic of brain endothelium.

Animals↗

PubMed1985

Progenitor cells from embryonic chick dorsal root ganglia differentiate in vitro to neurons: biochemical and electrophysiological evidence.

We have analyzed the appearance of neurons and glial cells in chick dorsal root ganglia during development. Neurons were identified by the presence of polysialogangliosides recognized by tetanus toxin (GD1b, GT1) or by the monoclonal antibody Q211 directed against polysialogangliosides containing four, five and six sialic acid residues. Glial cells were identified by the presence of 04 antigen. A population of undifferentiated cells, i.e., cells which express neither neuronal nor glial cell surface antigens, present in dorsal root ganglia until embryonic day 7, was separated from the neuronal and glial population. This cell population contains neuronal progenitor cells which differentiate to neurons within 1 day in culture. This differentiation process is characterized by the appearance of neuronal morphology, of neuron-specific gangliosides and by the appearance of voltage-dependent sodium and calcium channels.

Animals↗

PubMed1985

Developmental expression of GD3 and polysialogangliosides in embryonic chicken nervous tissue reacting with monoclonal antiganglioside antibodies.

The appearance and developmental distribution of GD3 and polysialogangliosides was studied immunohistochemically by means of the monoclonal mouse antibodies AbR24 and Q211. Cryostat sections of chicken embryos from 1 to 5 days (E1-E5) of incubation (Hamburger and Hamilton, stages 9-26) were prepared. GD3, detected by AbR24, is expressed on E2 by proliferating neuroepithelial cells of all regions of the developing brain and spinal cord and by migrating neural crest cells. As development continues, GD3 drops to a much lower level in postmitotic neurons, but is still strongly expressed by cells of the mitotically active germinal zones. In non-neural tissues the antigen was found in much lower concentrations than in the neuroectoderm, with the exception of very early, heavily proliferating endodermal and mesodermal epithelia. In contrast, the antigen(s) of the monoclonal mouse antibody Q211, identified on TLC-plates in polysialoganglioside fractions, was found to be specific for central and peripheral derivatives of the neural ectoderm. In the CNS, these polysialogangliosides are absent in the proliferating neural epithelium and appear for the first time on cells of the developing peripheral mantle layers at E2.5 (stage 17). Sections from all brain areas, retina, optic stalk, spinal cord, and peripheral nerves and ganglia of later stages (E4-5) showed that the antigen(s) of Q211 is expressed by neuronal perikarya and cell processes. The data strongly suggest that the developmental appearance of these polysialogangliosides is synchronized with the withdrawal of proliferating precursor cells from the mitotic cycle and differentiation to neurons.

Animals↗

PubMedDate not supplied

Inhibition of axonal growth by a monoclonal antibody.

Little is known about factors which control the outgrowth of neurites in the central nervous system (CNS) during development, although in vitro studies with neurones from the peripheral nervous system have shown that neurites require an appropriate substrate and specific factors for growth. To investigate the role of cell-surface components in the development of the CNS, we have raised a series of monoclonal antibodies against membrane components of cells from the visual system of the chick embryo. We report here that one of these antibodies, T61/3/12, clearly inhibits axonal outgrowth from chick retinal explants but does not affect axon growth from the peripheral nervous system.

Animals↗