Search PubMed⌕ Search

Biomedical subjects

R Nishi

Publications and source records attributed to R Nishi.

71 records · Page 4Linked to original sources
PubMed1981

Two components from eye tissue that differentially stimulate the growth and development of ciliary ganglion neurons in cell culture.

Survival and development of chick ciliary ganglion neurons in vivo appear to depend on information from the embryonic eye structure that contains the postsynaptic targets of the neurons. We have tested embryonic eye extracts on ciliary ganglion neurons in dissociated cell culture for stimulation of growth and development. Control conditions were chosen that permitted the long term maintenance of the neurons in the absence of tissue extracts of conditioned medium. The conditions included coating the culture substratum with fibroblast material and increasing the K+ concentration in the culture medium to 25 mM. Neurons survived for at least 3 weeks in control conditions. Two major components were resolved in eye extracts that stimulated growth and development of the neurons above the basal levels obtained with control conditions. One component, with an apparent molecular weight of about 2 X 10(4) by gel filtration analysis, stimulated neuronal growth without increasing the levels of choline acetyltransferase activity per neuron. The second component, with an apparent molecular weight of about 5 X 10(4), increased development of choline acetyltransferase levels per neuron but had no effect on neuronal growth. Both components were effective in normal K+ as well as 25 mM K+. These components may represent mechanisms by which the postsynaptic target tissue acts in vivo to direct the growth and development of ciliary ganglion neurons.

Animals↗
PubMed1979

Treatment of Mooren's ulcer by conjunctival excision.

3 early Mooren's ulcers were successfully treated by only one-time conjunctival excision adjacent to the ulcer, while in 2 other chronic vascularized Mooren's ulcers, repeated conjunctival excision was required for a final remission. The clinical outcome of these 5 eyes was better than that of 7 other eyes treated by conjunctival flap procedure, lamellar keratoplasty, topical eye drops or systemic medications. Four fragments of excised conjunctival tissue were examined histopathologically; the substantia propria was found to be infiltrated with plasma cells.

Adult↗
PubMed1977

Dissociated ciliary ganglion neurons in vitro: survival and synapse formation.

Normally, about half of the ciliary ganglion neurons in 8-day-old chick embryos die before day 14 in ovo. However, when dissociated ciliary ganglion neurons were prepared from either 8- or 14-day-old embryos and grown in cell culture with skeletal myotubes, essentially all of the neurons survived for at least 3 weeks. Many of the neurons formed functional synapses on myotubes under these conditions; some neuromuscular synapses could be detected as early as 20 hr after addition of the ganglion cells to muscle cultures. In contrast, most neurons from 8-day embryos survived for only a few days when grown alone on either polyornithine- or collagen-coated dishes. These results suggest that neurons destined to die in ovo can be rescued when grown in cell culture with myotubes and that under these conditions the neurons develop and express differentiated properties.

Animals↗
PubMedDate not supplied

Ability of developing epithelia to attract neurite outgrowth in culture is not correlated with the appearance of laminin.

Using a new technique for organ explants that facilitates the visualization of developing epithelia, we tested the abilities of salivary gland and lung rudiments to support de novo axonal outgrowth from the embryonic submandibular ganglion. We confirmed that salivary gland epithelia, but not lung epithelia, are able to support axonal outgrowth. This neurite outgrowth is also supported by salivary gland epithelia that have been lightly fixed with paraformaldehyde. When given a choice of both salivary gland and lung epithelia as a substrate for axonal outgrowth, the submandibular ganglion neurons showed an absolute preference for the salivary gland. Immunohistochemical localization of laminin was performed on whole mounts of developing epithelia after growing neurites were localized with a histochemical stain for esterase. Areas of lung epithelium devoid of any neurite outgrowth contained substantial immunoreactivity for laminin. In addition, Western blot analyses of extracts of embryonic lung and salivary gland indicate that the same amount of laminin or more is present on a per protein basis in the lung as in the salivary gland. An antiserum directed against laminin and a monoclonal antibody that blocks axonal regeneration on basal laminae in vitro (INO) were unable to block the outgrowth of axons over fixed epithelia. This suggests that molecules other than laminin are responsible for the preferential growth of axons over the salivary gland epithelia.

Animals↗