A quantitative study of the development of the nerves in the hind-limb of Eleutherodactylus martinicensis

Development ◽  
1965 ◽  
Vol 13 (1) ◽  
pp. 9-34
Author(s):  
Arthur Hughes
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Peripheral Nervous System ◽  
Quantitative Study ◽  
Hind Limb ◽  
The Caribbean

The present study is part of an attempt to collect information by different methods of approach to the development of the peripheral nervous system in the Caribbean Bufonid Eleutherodactylus martinicensis. Because of the small size and the rapidity of development of this animal, particular problems can be attempted with special and, in some instances, with unique facility. The present study is mainly concerned with changes in the number of constituent fibres in the nerves of the hind-limb during development. Here, where the number of fibres in any nerve never much exceeds a thousand, quantitative study is a less formidable task than in larger creatures. In other Anura, for instance, numbers would be at least five times greater. Although the fibres at particular sites of the adult nervous system have been counted, as for instance by Häggqvist (1936) in the spinal cord of man, and by Dunn (1902) in the limb nerves of the Frog, it does not seem that comparable studies on any developing animal have been undertaken.

Some effects of de-afferentation on the developing amphibian nervous system

Development ◽  
1965 ◽  
Vol 14 (1) ◽  
pp. 75-87
Author(s):  
Arthur Hughes
Keyword(s):  
Nervous System ◽  
Quantitative Study ◽  
Peripheral Nerves ◽  
Hind Limb ◽  
Sensory Input ◽  
Bufo Marinus ◽  
Degenerative Changes ◽  
Normal Embryo

An adult anuran can still walk or swim if the nerves supplying one or even two limbs are de-afferentated (Gray, 1950). However, in a developing amphibian, a limb at motile stages becomes paralysed when deprived of its sensory input. A sequence of degenerative changes then follow in the cord and in peripheral nerves. Tadpoles of Bufo marinus and late embryos of Eleutherodactylus martinicensis have been submitted to this experiment; in these tropical forms the subsequent events follow rapidly. Most attention has been paid to Eleutherodactylus, on which a quantitative study of the numbers of fibres in nerves to the hind limb during development has recently been published (Hughes, 1965a). This work, together with a study of the behaviour of the normal embryo (Hughes, 1965b) has been used as a basis for the present experimental observations. The source of the embryos of E. martinicensis and the methods of culturing and observing them remain the same as in previous studies (Hughes, 1962,1964a & b, 1965a & b).

scholarly journals The neuropathology of “typical” Friedreich's ataxia in Quebec

1984 ◽  
Vol 11 (S4) ◽  
pp. 592-600 ◽  
Author(s):  
J.B. Lamarche ◽  
B. Lemieux ◽  
H.B. Lieu
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Nervous System ◽  
Peripheral Nervous System ◽  
Diagnostic Criteria ◽  
Clinical Findings ◽  
Spinal Ganglia ◽  
Cooperative Study ◽  
Segmental Demyelination ◽  
Dying Back

AbstractWe present the pathological data from the autopsies performed on 6 Friedreich's disease patients since the start of the Quebec Cooperative Study. All patients met the strict diagnostic criteria of the QCSFA. The anatomical lesions found in the peripheral and central nervous system were similar in all 6 cases and do not differ from those described in the literature. The clinical findings correlate closely with the histological lesions found in the peripheral nervous system and spinal cord. The evidence of segmental demyelination and remyelination in the spinal ganglia and posterior roots further supports the dying-back axonopathy hypothesis.

scholarly journals Sampling and Evaluating the Peripheral Nervous System

2019 ◽  
Vol 48 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Mark T. Butt
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Sciatic Nerve ◽  
Peripheral Nervous System ◽  
Morphological Changes ◽  
Sampling Strategy ◽  
Mechanisms Of Toxicity ◽  
Test Article ◽  
Ganglion Neurons ◽  
The Brain

Many preclinical investigations limit the evaluation of the peripheral nervous system (PNS) to paraffin-embedded sections/hematoxylin and eosin–stained sections of the sciatic nerve. This limitation ignores several key mechanisms of toxicity and anatomic differences that may interfere with an accurate assessment of test article effects on the neurons/neurites peripheral to the brain and spinal cord. Ganglion neurons may be exposed to higher concentrations of the test article as compared to neurons in the brain or spinal cord due to differences in capillary permeability. Many peripheral neuropathies are length-dependent, meaning distal nerves may show morphological changes before they are evident in the mid-sciatic nerve. Paraffin-embedded nerves are not optimal to assess myelin changes, notably those leading to demyelination. Differentiating between axonal or myelin degeneration may not be possible from the examination of paraffin-embedded sections. A sampling strategy more consistent with known mechanisms of toxicity, atraumatic harvest of tissues, optimized fixation, and the use of resin and paraffin-embedded sections will greatly enhance the pathologist’s ability to observe and characterize effects in the PNS.

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