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Biomedical subjects

R E Bonyhady

Publications and source records attributed to R E Bonyhady.

7 recordsLinked to original sources
PubMed1985

An analysis of peripheral neuronal survival factors present in muscle.

Extracts of bovine heart, rat heart, and rat skeletal muscle were chromatographically separated and the fractions tested for their ability to maintain the survival of dissociated sympathetic, parasympathetic, and sensory neurones. Bovine heart contained at least five, rat heart at least six, and rat skeletal muscle at least four active components differing in their physicochemical properties and their target selectivity. Bovine and rat heart appeared to contain at least two components in common. The differences in active components found in the three tissues are consistent with a complex and perhaps tissue-specific system regulating neuronal survival.

Animals↗
PubMed1982

Reversible dissociation of a bovine cardiac factor that supports survival of avian ciliary ganglionic neurones.

The relationship has been studied between a high and a low molecular weight form of a bovine cardiac factor that supports the survival of avian ciliary ganglionic neurones in culture. Reversible dissociation of the high molecular weight form into identical or similarly sized subunits of apparent molecular weight in the range 15,000-30,000 has been demonstrated. In addition, other inactive high molecular weight components of cardiac extract were found to interact synergistically with both active forms of the factor.

Animals↗
PubMed1981

Interactions between developing autonomic neurons and their target tissues.

Neurons critically depend on contact with the correct target tissue in order to survive and mature. The number of neurons surviving in a nerve centre directly depends on the size of the peripheral field in innervates. It has been proposed that target tissues release a neurotrophic substance (retrophin) which is internalized by nerve terminals and retrogradely transported to the perikarya where its action results in the survival of appropriate neurons. In the sympathetic nervous system, nerve growth factor probably acts as a retrophin. Similar retrophins must exist for other neuronal systems. In order to identify a parasympathetic retrophin two approaches have been taken. One was to grow appropriate target tissues with radiolabelled amino acids and to determine whether the proteins synthesized and released by these target tissues were retrogradely transported by parasympathetic neurons in vivo. The other approach was to show that a purified neurotrophic factor for the chick ciliary ganglion could be retrogradely transported by parasympathetic neurons. The results have suggested that at least two retrophins are involved in the normal development of the autonomic nervous system: one, nerve growth factor, for the sympathetic nervous system and the other, as yet unnamed, for the parasympathetic system.

Afferent Pathways↗
PubMed1980

Characterization of a cardiac muscle factor required for the survival of cultured parasympathetic neurones.

A macromolecule from ox cardiac muscle which supports the survival of dissociated embryonic chick ciliary ganglionic neurones in culture has been partially purified and characterized. Gel filtration after ammonium sulphate fractionation separated two peaks of activity, a high molecular weight form (greater than 50,000) which dissociated to a lower molecular weight component (approximately 20,000). The high molecular weight form was retained by DEAE-cellulose at neutral pH and was eluted by 0.11-0.16 M NaCl. The isoelectric point of the factor was 6.2.

Animals↗
PubMedDate not supplied

Effects of haemin on neurones derived from the neural crest.

Haemin at high concentrations promoted the survival and neuritic outgrowth in vitro of dissociated sensory and parasympathetic neurones from 8-day-old chick embryos. Similar concentrations of haemin increased the activities of the neurotransmitter biosynthetic enzymes, tyrosine hydroxylase and choline acetyltransferase, in explant cultures of neonatal rat sympathetic ganglia, and in explant and dissociated 14-day-old embryonic chick parasympathethic ganglia, respectively. Enzyme activities of both dissociated neonatal rat sympathetic ganglia and explant and dissociated 8-day-old embryonic chick parasympathetic ganglia were not affected by haemin. Since the neurotrophic effects of haemin were small compared to those of tissue extracts, and were seen mainly at concentrations approaching the limits of its solubility, it is concluded that haemin resulting from the breakdown of haem proteins in tissue extracts is unlikely to contribute significantly to their effects.

Animals↗