Solid Phase Synthesis of a Functionalized Bis-Peptide Using …
Published 5/15/2012
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In JoVE (1)
Other Publications (4)
Articles by Toby A. Ferguson in JoVE
Reproducible Mouse Sciatic Nerve Crush and Subsequent Assessment of Regeneration by Whole Mount Muscle Analysis
Center for Neural Repair and Rehabilitation, Temple University
In this report we describe a method to crush mouse sciatic nerve. This method uses readily available hemostatic forceps and easily and reproducibly produces complete sciatic nerve crush. In addition, we describe a method to prepare muscle whole mounts suitable for analysis of nerve regeneration after sciatic nerve crush.
Other articles by Toby A. Ferguson on PubMed
Regeneration of Axons After Nerve Transection Repair is Enhanced by Degradation of Chondroitin Sulfate Proteoglycan
Our past work indicates that growth-inhibiting chondroitin sulfate proteoglycan (CSPG) is abundant in the peripheral nerve sheaths and interstitium. In this study we tested if degradation of CSPG by chondroitinase enhances axonal regeneration through the site of injury after (a) nerve crush and (b) nerve transection and coaptation. Adult rats received the same injury bilaterally to the sciatic nerves and then chondroitinase ABC was injected near the injury site on one side, and the contralateral nerve was injected with vehicle alone. Nerves were examined 2 days after injury in the nerve crush model and 4 days after injury in the nerve transection model. Chondroitinase-dependent neoepitope immunolabeling showed that CSPG was thoroughly degraded around the injury site in the chondroitinase-treated nerves. Axonal regeneration through the injury site and into the distal nerve was assessed by GAP-43 immunolabeling. Axonal regeneration after crush injury was similar in chondroitinase-treated and control nerves. In contrast, axonal regrowth through the coaptation of transected nerves was markedly accelerated and the ingress of axons into the distal segment was increased severalfold in nerves injected with chondroitinase. On the basis of these results we concluded that growth inhibition by CSPG contributes critically to the poor regenerative growth of axons in nerve transection repair. In addition, degradation of CSPG by injection of chondroitinase ABC at the site of nerve repair increased the ingress of axonal sprouts into basal laminae of the distal nerve segment, presumably by enabling more latitude in growth at the interface of coapted nerve. This suggests that chondroitinase application may be used clinically to improve the outcome of primary peripheral nerve repair.
Clinical Presentation and Diagnosis of Amyotrophic Lateral Sclerosis
Progressive loss of motor neurons causes Amyotrophic Lateral Sclerosis. Patients complain, most often, of progressive weakness in the distal limbs. However, weakness may manifest in any body segment (bulbar, cervical, thoracic, or lumbosacral). The diagnosis of ALS is suggested by clinical examination that reveals both upper and lower motor neuron failure. Formal diagnostic criteria have been developed and validated. Nerve conduction and electromyography studies improve diagnostic sensitivity and exclude some alternate, treatable diagnoses. Likewise, conventional imaging studies and laboratory evaluation refute other diseases that may masquerade as ALS. Experimental imaging and laboratory evaluations may improve ALS diagnosis in the future. The cause of motor neuron death is not known but inherited forms of motor neuron disease may suggest mechanisms. The goal of ALS treatment is control of the symptoms of progressive weakness, especially respiratory insufficiency and dysphagia and is best managed in an integrated clinic.
Missense Mutations in the Copper Transporter Gene ATP7A Cause X-linked Distal Hereditary Motor Neuropathy
Distal hereditary motor neuropathies comprise a clinically and genetically heterogeneous group of disorders. We recently mapped an X-linked form of this condition to chromosome Xq13.1-q21 in two large unrelated families. The region of genetic linkage included ATP7A, which encodes a copper-transporting P-type ATPase mutated in patients with Menkes disease, a severe infantile-onset neurodegenerative condition. We identified two unique ATP7A missense mutations (p.P1386S and p.T994I) in males with distal motor neuropathy in two families. These molecular alterations impact highly conserved amino acids in the carboxyl half of ATP7A and do not directly involve the copper transporter's known critical functional domains. Studies of p.P1386S revealed normal ATP7A mRNA and protein levels, a defect in ATP7A trafficking, and partial rescue of a S. cerevisiae copper transport knockout. Although ATP7A mutations are typically associated with severe Menkes disease or its milder allelic variant, occipital horn syndrome, we demonstrate here that certain missense mutations at this locus can cause a syndrome restricted to progressive distal motor neuropathy without overt signs of systemic copper deficiency. This previously unrecognized genotype-phenotype correlation suggests an important role of the ATP7A copper transporter in motor-neuron maintenance and function.
Extrinsic and Intrinsic Determinants of Nerve Regeneration
After central nervous system (CNS) injury axons fail to regenerate often leading to persistent neurologic deficit although injured peripheral nervous system (PNS) axons mount a robust regenerative response that may lead to functional recovery. Some of the failures of CNS regeneration arise from the many glial-based inhibitory molecules found in the injured CNS, whereas the intrinsic regenerative potential of some CNS neurons is actively curtailed during CNS maturation and limited after injury. In this review, the molecular basis for extrinsic and intrinsic modulation of axon regeneration within the nervous system is evaluated. A more complete understanding of the factors limiting axonal regeneration will provide a rational basis, which is used to develop improved treatments for nervous system injury.