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Biomedical subjects

R P Nuttall

Publications and source records attributed to R P Nuttall.

9 recordsLinked to original sources
PubMed1986

Age and cell type influences on nerve--non-nerve contact interactions.

Eight-day ciliary ganglion neurons respond in a significantly different fashion to contact with dorsal root ganglia non-neurons than do 8-day dorsal root neurons. The ciliary neuron-dorsal root non-neuron interactions result in contact inhibition of both cells, whereas in the dorsal root neuron-dorsal root non-neuron case no such inhibition is observed. In addition, contact of 8- and 14-day ciliary neurons with heart fibroblasts results in inhibition of locomotion. However, the response of the fibroblast to contact with these neurons of different ages varies in a predictable fashion.

Age Factors↗
PubMed1983

Differential response to contact during embryonic nerve-nonnerve cell interactions.

The outcome of contact interactions involving neurons and nonneurons varies depending on the cell types involved. When neuronal growth cones from either ciliary (motor) or dorsal root (sensory) ganglia directly contact the lamellipodium of an embryonic heart fibroblast, both neurite elongation and fibroblast locomotion are inhibited. This occurs in spite of the fact that cell-surface activity in both cells continues unabated. Such contact inhibition is not observed when homologous ganglionic nonneurons are involved in the interaction. In fact, these cells become intimately associated with growth cones and/or neuritic shafts as a result of the contact. The detailed nature of the response to contact exhibited by nerves and nonnerves varies not only with cell type but also with the portion of the cell involved in the contact. Growth cone filopodia tend to actively palpate the fibroblast surface, whereas spread regions, termed "veils," form areas of apposition with fibroblast lamellipodia. This latter situation resembles the "typical" contact inhibition of locomotion that occurs following embryonic heart fibroblast-fibroblast interactions. Growth cones also frequently exhibit contact guidance when interacting with nonruffling lateral surfaces of heart fibroblasts.

Animals↗
PubMed1980

Responses to cell contacts between growth cones, neurites and ganglionic non-neuronal cells.

The motility of growth cones of embryonic peripheral neurons is not inhibited by contact with the surfaces of neurites or of non-neuronal cells. Rather, growth cones and microspikes adhere to other cell surfaces and often respond with forward movement and elongation in contact with other cells, as they do on adhesive surfaces in vitro. Furthermore, non-neuronal cells do not display contact inhibition when they contact growth cones or neurites. If anything, surface motility and ruffling is stimulated by contact with a neuronal cell surface and some non-neuronal cells prefer to migrate along neurites rather than on the surface of the culture dish. These observations on the contact behaviour of cells from peripheral nerve ganglia imply that the surfaces of embryonic neurons differ from those of non-neuronal cells in that the neuronal surfaces do no elicit the typical contact inhibition response.

Animals↗
PubMed1976

Epithelial stratification in the developing chick cornea.

The process of epithelial stratification was studied in the embryonic chick corneal eipthelium between 10 and 21 days of incubation. Information was collected on the DNA synthetic activity occurring in individual cell layers, on cell density changes in the basal layer, and on mitotic spindle orientation in each cell layer before, during, and upon the completion of alyer formation. Prior to the initiation of stratification, mitotic spindles are oriented parallel to the basement membrane interface. This orientation changes to predominantly vertically directed spindles as layer formation proceeds. Later, the majority of the spindles are horizontally aligned once more. This pattern was observed as each successive cell layer formed. The possible relationship between the spindle data and that obtained on DNA synthetic activity and cell density changes is discussed in terms of the role these factors might play in layer formation in the cornea, as well as in other stratified epithelia.

Animals↗
PubMed1976

DNA synthesis during the development of the chick cornea.

The frequency and pattern of DNA synthesis were analysed autoradiographically in the developing chick cornea. Each cellular population was studied in time-sequence fashion from the time of its appearance until hatching. There is a sharp drop in the synthetic index (number of labeled cells/total number of cells) in the anterior corneal epithelium soon after its formation, corresponding in time to the secretion of extracellular matrix material by this tissue. A similar decrease does not occur in adjacent tissues. Continous labeling experiments show that about 20% of the corneal cells are not in the proliferative pool at this time while 100% of the cells in the underlying lens epithelium and the surrounding head epidermis and head mesenchyme are labeled. Cell cycle measurements indicate that the proliferative kinetics of both the corneal epithelium and the head epidermis are similar at this time even though the percentage of labeled cells in each region differs. The formation of the corneal endothelium and the movement of fibroblasts into the stromal region are events which involve extensive cellular migration. Labeled cells are observed at all stages of both endothelial and stromal fibroblast migration, indicating that DNA synthesis occurs during the course of cellular migration in the developing cornea.

Animals↗
PubMed1976

Differential labeling of the cell surface of single ciliary ganglion neurons in vitro.

Cationic ferritin binds in a time and concentration dependent manner to all surfaces of ciliary ganglion neurons in culture except "mounds" and "veils". In chase experiments, bound ferritin clears from the cells surfaces and forms larger and larger patches, even at low temperatures. Binding of cationic ferritin is inhibited by poly-L-lysine, potentiated by poly-L-glutamate, and not affected by neruaminidase (acylneuraminyl hydrolase, EC 3.2.1.18), hyaluronidase (hyaluronoglucosidase, hyaluronate 4-glycanhydrolase, EC 3.2.1.35), or chondroitin ABC lyase (EC 4.2.2.4).

Ammonium Chloride↗