Sequential loss of myelin proteins during Wallerian degeneration in the human spinal cord.

Axons undergo Wallerian degeneration (WD) distal to a point of injury. In the lesioned PNS, WD may be followed by successful axonal regeneration and functional recovery. However, in the lesioned mammalian CNS, there is no significant axonal regeneration.

Expression pattern of NOGO-A protein in the human nervous system.

The distribution pattern of NOGO-A protein, an important axon growth inhibitory molecule and member of the reticulon family, has been investigated in the adult human brain, spinal cord, retina and dorsal root ganglia. Intense NOGO-A immunoreactivity was detected in oligodendroglial cell bodies and their myelin sheaths in nerve fibre tracts of the central nervous system. Furthermore, numerous populations of neurons in the brain and spinal cord expressed NOGO-A to a variable extent in their cell bodies and neurites, suggesting additional, as-yet-unknown, functions of this protein.

Microsurgical therapy of symptomatic lumbar juxta facet cysts.

Objective: Symptomatic lumbar juxta facet cysts (ganglion and synovial cysts) (JFC) are uncommon lesions of the spine, causing radiculopathy and low back pain. The authors present their experiences with microsurgically treated JFC. This rare pathology is discussed with special focus on therapeutic concepts and long-term outcome.

Repetitive transcranial magnetic stimulation improves open field locomotor recovery after low but not high thoracic spinal cord compression-injury in adult rats.

Electromagnetic fields are able to promote axonal regeneration in vitro and in vivo. Repetitive transcranial magnetic stimulation (rTMS) is used routinely in neuropsychiatric conditions and as an atraumatic method to activate descending motor pathways. After spinal cord injury, these pathways are disconnected from the spinal locomotor generator, resulting in most of the functional deficit.

Identification of regeneration-associated genes after central and peripheral nerve injury in the adult rat.

Background: It is well known that neurons of the peripheral nervous system have the capacity to regenerate a severed axon leading to functional recovery, whereas neurons of the central nervous system do not regenerate successfully after injury. The underlying molecular programs initiated by axotomized peripheral and central nervous system neurons are not yet fully understood.

Results: To gain insight into the molecular mechanisms underlying the process of regeneration in the nervous system, differential display polymerase chain reaction has been used to identify differentially expressed genes following axotomy of peripheral and central nerve fibers.

Vocal cord palsy resulting from spontaneous carotid dissection.

Objectives/hypothesis: Vocal cord palsy has a variety of causes, such as malignant tumors of the thyroid, lung, or upper mediastinum, aortic aneurysm, surgery of the thyroid, and infectious diseases.

Study Design: Case report.

Methods: A 43-year-old biologist had a holocephalic headache and right-sided neck pain for 1 day.

Increased expression of the putative axon growth-repulsive extracellular matrix molecule, keratan sulphate proteoglycan, following traumatic injury of the adult rat spinal cord.

Keratan sulphate proteoglycan (KSPG) is a developmentally regulated barrier molecule, directing axonal growth during central nervous system (CNS) formation. The possible re-expression and functional significance of KSPG in preventing axon regeneration following spinal cord injury (SCI) is poorly understood. In the present investigation, the spatio-temporal expression of KSPG was studied following experimental SCI.

Columns of Schwann cells extruded into the CNS induce in-growth of astrocytes to form organized new glial pathways.

Our previous work showed that stereotaxic microextrusion of columns of purified peripheral nerve-derived Schwann cells into the thalamus of syngeneic adult rats induces host axons to grow into the column and form a new fiber tract. Here we describe the time course of cellular events that lead to the formation of this new tract. At 2 h postoperation, numerous OX42-positive microglia accumulated at the graft-host interface, after which donor columns became progressively and heavily infiltrated by microglia/macrophages that took on an elongated morphology in parallel with the highly orientated processes of the donor Schwann cells.

Major histocompatibility complex class II expression by activated microglia caudal to lesions of descending tracts in the human spinal cord is not associated with a T cell response.

Lesion-induced microglial/macrophage responses were investigated in post-mortem human spinal cord tissue of 20 patients who had died at a range of survival times after spinal trauma or brain infarction. Caudal to the spinal cord injury or brain infarction, a strong increase in the number of activated microglial cells was observed within the denervated intermediate grey matter and ventral horn of patients who died shortly after the insult (4-14 days). These cells were positive for the leucocyte common antigen (LCA) and for the major histocompatibility complex class II antigen (MHC II), with only a small proportion staining for the CD68 antigen.

Attempted endogenous tissue repair following experimental spinal cord injury in the rat: involvement of cell adhesion molecules L1 and NCAM?

It is widely accepted that the devastating consequences of spinal cord injury are due to the failure of lesioned CNS axons to regenerate. The current study of the spontaneous tissue repair processes following dorsal hemisection of the adult rat spinal cord demonstrates a phase of rapid and substantial nerve fibre in-growth into the lesion that was derived largely from both rostral and caudal spinal tissues. The response was characterized by increasing numbers of axons traversing the clearly defined interface between the lesion and the adjacent intact spinal cord, beginning by 5 days post operation (p.

5'-Nucleotidase activity of mossy fibers in the dentate gyrus of normal and epileptic rats.

Sprouting of mossy fibers in the hippocampus of rats that underwent limbic epileptogenesis by amygdala kindling or kainate injection was studied at the light microscopic and ultrastructural levels by cytochemical demonstration of the enzyme 5'-nucleotidase. This adenosine-producing ectoenzyme has previously been shown to characterize malleable terminals during brain development and lesion-induced synaptogenesis, but to be otherwise associated with glial membranes. At the light microscopic level, kainate-treated but not control or kindled rats showed 5'-nucleotidase activity in the CA3 region and in the inner molecular layer of the dentate gyrus.

GAP-43 (B-50) and C-Jun are up-regulated in axotomized neurons of Clarke's nucleus after spinal cord injury in the adult rat.

The growth-associated protein GAP-43 (B-50) and the transcription factor C-Jun are involved in regeneration of the injured nervous system. In this study, we investigated the possibility of the induction of GAP-43 and C-Jun in axotomized neurons of Clarke's nucleus (CN) in adult rats, of which a large population undergoes degeneration several weeks after a low thoracic lateral funiculotomy of the spinal cord. In situ hybridization and immunohistochemistry revealed a transient up-regulation of GAP-43 mRNA, C-Jun protein, and its activated, phosphorylated form, peaking around 7 days after injury in preferentially large diameter CN-neurons ipsilateral and caudal to the lesion.

Astrocytes re-express nestin in deafferented target territories of the adult rat hippocampus.

Up-regulation of the intermediate filament protein, nestin, is a sensitive indicator for the extent of astrocytic activation in regions of CNS close to the point of injury. However, it remains unclear whether activated astrocytes in distant, deafferented CNS territories are also capable of nestin re-expression. Here, we demonstrate that traumatic injury to the dentate gyrus is followed by the rapid but transient expression of nestin in astrocytes located in the stratum lucidum of field CA3.

Spontaneous longitudinally orientated axonal regeneration is associated with the Schwann cell framework within the lesion site following spinal cord compression injury of the rat.

Spontaneous cellular reorganisation at the lesion site has been investigated following massive spinal cord compression injury in adult rats. By 2 days post operation (p.o.

Distribution of B-50(GAP-43) mRNA and protein in the normal adult human spinal cord.

B-50(GAP-43) is a phosphoprotein mainly found in the nervous system which plays a major role in neurite growth during development and regeneration as well as in synaptic remodelling. In the mature intact central nervous system, intense B-50 immunoreactivity (B-50-IR) can still be detected in regions which maintain residual capacity for structural re-organization. B-50 expression has been studied extensively in laboratory animals; however, its distribution and regulation in the human spinal cord is largely unknown.

A novel early component of the cell body response in axotomized Clarke's nucleus neurons revealed by monoclonal antibody Py.

The monoclonal antibody Py was initially developed as a tool for the identification of subpopulations of hippocampal neurons. Recently it has also been demonstrated to be a useful marker for other populations of midbrain and spinal cord neurons in which the antigen showed a strong colocalization with cytoskeletal elements. To assess the possible usefulness of Py as a tool for studying lesion-induced cell body changes, densitometric analysis of altered Py-immunoreactivity (Py-IR) has been compared with that of microtubule-associated protein 2 (MAP2) in Clarke's nucleus following axotomy.

Axotomy-induced alterations in the red nucleus revealed by monoclonal antibody, Py, following a low thoracic spinal cord lesion in the adult rat.

The monoclonal antibody Py was previously developed as a tool for the identification of subpopulations of hippocampal neurons. Here, the differential distribution of Py immunoreactivity in the mid-brain is described showing that Py also serves as a useful marker for other populations of neurons. Medium to strong immunoreactivity was observed in the cell body and dendrites of neurons of the oculomotor nucleus, superior colliculus and substantia gelatinosa reticulata.

Differential distribution of immunoreactivity in the adult rat spinal cord revealed by the monoclonal antibody, Py: a light and electron microscopic study.

The monoclonal antibody Py has previously been shown to be a useful marker for subpopulations of neurons in the rat brain. However, the distribution of Py immunoreactivity in other regions of the CNS and PNS is not known. Here, we present a light and electron microscopic investigation into the distribution of Py immunoreactivity in the adult rat spinal cord, dorsal root ganglia, and peripheral nerves.

5'-nucleotidase enzyme cytochemistry as a tool for revealing activated glial cells and malleable synapses in CNS development and regeneration.

The demonstration of 5'-nucleotidase in neural tissue is achieved at both the light and electron microscopic levels by means of an enzyme cytochemical lead method, which is specific, sensitive and fast. By its activity this adenosine-producing ecto-enzyme (EC 3.1.

B-50 (GAP-43) in the rat spinal cord caudal to hemisection: lack of intraspinal sprouting by dorsal root axons.

The controversial hypothesis that intraspinal sprouting by dorsal root axons promotes reinnervation of partially denervated neurons caudal to a low thoracic cord hemisection was re-investigated in rats using quantitative immunohistochemical analysis of the neural specific growth-associated protein B-50 (GAP-43) at postoperative survival times of 3, 10, 21, 42, and 90 days. The lack of increase in B-50-immunoreactivity in all segments below the hemisection at all survival times does not support the concept of intraspinal sprouting following the removal of supraspinal descending pathways.

Evidence that 5'-nucleotidase is associated with malleable synapses--an enzyme cytochemical investigation of the olfactory bulb of adult rats.

The adenosine-producing ecto-enzyme 5'-nucleotidase has recently been assigned to malleable axon terminals in both the developing and regenerating adult nervous system, but is otherwise only glia-bound. Using a cytochemical lead method, we now show that 5'-nucleotidase activity is localized predominantly at glomerular and mitral synapses within the main olfactory bulb of normal, adult rats. As these terminals are prone to synaptic turnover even at maturity, the present findings favour the view that this enzyme constitutes a marker molecule for plastic synapses.

B-50 (GAP-43) in the spinal cord caudal to hemisection: indication for lack of intraspinal sprouting in dorsal root axons.

Sprouting of dorsal root axons has been suggested to occur in the mature cat spinal cord caudal to a hemisection at a low thoracic level sparing the dorsal columns. The lesion interrupts supraspinal descending projections, while leaving ascending collaterals of dorsal root axons intact. This hypothesis was re-evaluated by comparing the light and electron microscopic immunoreactivity of B-50 (GAP-43) on both sides of the postulated target regions for sprouting, the intermediate gray and the dorsal horn.

B-50 (GAP-43) in Onuf's nucleus of the adult cat.

The nucleus of Onuf in the sacral spinal cord contains motoneurons that innervate the pelvic floor muscles and possess somatic and autonomic characteristics. We show in this study that in the intact adult cat, the immunocytochemical labelling of the nervous tissue-specific growth-associated protein, B-50 (GAP-43), which persists in Onuf's nucleus, differs markedly from that in the remaining 'purely somatic' motor nuclei of the sacral spinal cord. At the light microscopic level, an intense B-50 (GAP-43) immunoreactivity (B-50-IR) in the neuropil of Onuf's nucleus contrasts with a faint staining in the other spinal motor nuclei.