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At least 649 records · Page 36Linked to original sources
PubMed2006

Anaplastic lymphoma kinase is dynamically expressed on subsets of motor neurons and in the peripheral nervous system.

During embryonic development, complex events, such as cellular proliferation, differentiation, survival, and guidance of axons, are orchestrated and regulated by a variety of extracellular signals. Receptor tyrosine kinases mediate many of these events, with several playing critical roles in neuronal survival and axonal guidance. It is evident that not all the receptor tyrosine kinases that play key roles in regulating neuronal development have been identified. In this study, we have characterized the spatial-temporal expression profile of a recently identified receptor tyrosine kinase, anaplastic lymphoma kinase (ALK), in embryonic chick by means of whole-mount in situ hybridization in conjunction with immunohistochemistry. Our findings reveal that Alk is expressed in sympathetic and dorsal root ganglia as early as stage 19. In addition, mRNA is expressed from stage 23/24 (E4) to stage 39 (E13) in discrete motor neuron subsets of chick spinal cord along with a select group of muscles that are innervated by one of these particular motor neuron clusters. Expression within the spinal cord is coincident with the onset and duration of motor neuron programmed cell death and during the period of musculature innervation and synapse formation. Hence, the data presented here identify ALK as a novel candidate receptor for regulating critical events in the development of neurons in both the central and the peripheral nervous systems.

Anaplastic Lymphoma Kinase↗
PubMedDate not supplied

Application of the Cajal-De Castro method to the laser scanning confocal microscope in studying the peripheral nervous system.

We tested the Cajal-De Castro method with the Laser Scanning Confocal Microscope (LSCM). This method is a valid investigatory tool for anatomical-morphological study and for the tridimensional reconstruction of the structures of the peripheral nervous system. The combination technique makes it possible to exploit the properties of reflection and fluorescence of the deposited reduced silver. The quantity of which is dependent on the different tissue affinity. On the other hand, since scanning in fluorescence is not selective, both the nerve structures and the surrounding tissue are evidenced and the structures that demonstrate more specific affinity for silver salt are more prominent. Being able to study the preparations using both methods contemporaneously makes it possible to obtain very significant tridimensional images that abound in detail. The Cajal-De Castro method also offers interesting possibilities in the morphometric field and in image analysis.

Amphibians↗
PubMed1985

Activity of 2'3'-cyclic-nucleotide 3'-phosphodiesterase and content of PO protein in the peripheral nervous system of the dystrophic mouse and chicken.

To investigate whether various myelin markers could detect pathological changes in myelination, the activity of 2'-3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and the level of PO protein were compared in the peripheral nervous system (PNS) of the dystrophic mouse and chicken and their phenotypically normal siblings. The same comparison was made for subcellular fractions of these nerves. The level of PO protein and the activity of CNP were normal in the spinal roots of sciatic nerves of the 129B6F1/Jdy/dy strain of dystrophic mouse. These parameters were slightly but significantly lower in the spinal roots of the 129REJ/dy/dy strain of dystrophic mouse. These results suggest that the 129B6F1/Jdy/dy mutant and the 129REJ/dy/dy mutant mouse might not have the same type of biochemical abnormality in their PNS. The specific activity of CNP and the proportion of PO protein increased significantly in the various regions of the PNS of 1-day-old chicks when compared to that of the 18-day-old embryos. Subcellular fractionation of peripheral nerves indicated that these components were enriched in the crude myelin fraction. These results support the conclusion that PO protein and CNP are suitable markers of myelinogenesis in the PNS of the chick. These parameters were normal in the line 413 dystrophic chicken. These results do not support the conclusion of a systemic membrane defect in the PNS of the dystrophic mouse and chicken.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1996

Axonal transport and distribution of synaptobrevin I and II in the rat peripheral nervous system.

Synaptobrevin, a membrane protein of synaptic vesicles that plays a key role in exocytosis, occurs in two closely related isoforms, synaptobrevin I and II. We have analyzed the axonal transport of both isoforms in sciatic nerve and spinal roots. When fast axonal transport was interrupted by crushing, the proteins accumulated continuously proximal to the crush. Accumulation also was observed distal to the crush, but to a lesser extent (47 and 63% of the proximal accumulation for synaptobrevin I and II, respectively). Immunoelectron microscopy revealed that, proximal to the crush, synaptobrevin I and II were associated with small clear vesicles reminiscent of typical synaptic vesicles. Distal to the crush, membranes positive for synaptobrevin I or II were more heterogeneous, including larger membrane profiles that may represent endosomes. In spinal cord, synaptobrevin I and II were colocalized in many terminals. However, labeling for synaptobrevin I was more intense whereas labeling for synaptobrevin II was stronger in dorsal than in ventral horn terminals. Motor endplates contained only synaptobrevin I. In the sciatic nerve, synaptobrevin I was present predominantly in large, myelinated axons, whereas synoptobrevin II was virtually absent but abundant in small- and medium-sized axons. Lumbar sympathectomy, ventral rhizotomy, and double-labeling studies confirmed that synaptobrevin I is present predominantly in motor neurons whereas synaptobrevin II is present in adrenergic and sensory neurons. We conclude that synaptobrevin I and II are transported bidirectionally by fast axonal transport and are expressed heterogeneously in different neurons in the peripheral nervous system of the adult rat, suggesting that these isoforms have special functional roles in different sets of neurons.

Animals↗
PubMed1987

Induction and segregation of glial intermediate filament expression in the RT4 family of peripheral nervous system cell lines.

We have found glial fibrillary acidic protein (GFAP), the major component of astrocyte intermediate filaments, to be expressed in cell lines of the RT4 peripheral neurotumor family. The RT4 family is a "stem-cell-like" cell line, RT4-AC, that spontaneously undergoes differentiation in culture to three derivative cell types. This process, termed cell-type conversion, results in a segregation among the derivative cell types of parental cell phenotypes that have been described as neuronal-like or glial-like. We have identified a 50-kDa GFAP-immunoreactive cytoskeletal protein and GFAP mRNA in continuous RT4-AC and RT4-D (glial-type derivative) cell lines, but not in two presumptive neuronal-type cell lines. This result suggests that GFAP gene expression is coordinately coupled with the expression of other glial properties during cell-type conversion. In addition, the RT4-AC and RT4-D sublines were found to significantly express GFAP only at high cell densities and not during logarithmic growth and to express GFAP precociously during morphological differentiation following treatment with 1 mM N6, O2'-dibutyryladenosine 3',5'-cyclic monophosphate. These observations closely reflect reports of glial filament expression in astrocyte cultures, suggesting that a common regulatory mechanism is employed by central and peripheral nervous system glia.

Animals↗
PubMed1990

[Adverse effects of cyclosporin A with special reference to the peripheral nervous system].

Since the introduction of Cyclosporine A (CsA) in 1972, several studies have focused on its effects on experimental autologous peripheral nerve transplants. Although several studies have reported neurotoxicity of CsA in the central nervous system, no such data exist regarding the peripheral nervous system. The present study focuses on the effects of CsA in the therapeutic and toxic doses on axon regeneration, particularly the rate and quality of axon regeneration. Autologous nerve transplantation was performed in Lewis rats and axon regeneration evaluated clinically (motor function, body weight), electroneurographically and histologically. In transplanted nerves, even high doses of CsA (30 mg/kg bodyweight) did not lead to delayed or impaired axon regeneration. Long-term application in normal peripheral nerves did however cause axon degeneration with edema and vacuolisation of myelin sheaths, retraction of myelin sheaths from the node of Ranvier, and marked enhancement of the Schmidt-Lantermann incisures. As neurological side effects such as tremor and paresthesia have been reported under application of CsA in man, the above data might be of clinical relevance.

Animals↗
PubMed2004

Comparative genomic hybridization in central and peripheral nervous system tumors of childhood and adolescence.

Brain tumors amount to less than 2% of all malignant neoplasms. However, they account for approximately 20% of all childhood cancers and are the leading cause of cancer mortality among children. Recently, enormous progress has been achieved in the field of pediatric neuro-oncology regarding the classification of children's brain tumors, as well as the understanding of the genetic events involved in their pathogenesis; thus leading to an emerging role of molecular diagnostic approaches using novel tools. Comparative genomic hybridization (CGH) is a technique that has revolutionized cytogenetic knowledge in the past decade. It permits the detection of chromosomal copy number changes without the need for cell culturing and gives a global overview of chromosomal gains and losses throughout the whole genome of a tumor. A survey of CGH-related publications on central and peripheral nervous system tumors in the pediatric and adolescent population revealed 884 cases. The CNS tumor groups most frequently examined by CGH were embryonal tumors (268 cases/30.3%) and ependymomas (241/27.2%), followed by astrocytic (163/18.4%), peripheral nerve (73/8.2%), choroid plexus tumors (56/6.3%), and craniopharyngiomas (38/4.3%). The most common CNS tumor entities were medulloblastomas (238/26.9%), classic ependymomas (160/18.1%), anaplastic ependymomas (70/7.9%), pleomorphic xanthoastrocytomas (53/6.0%), and pilocytic astrocytomas (50/5.6%). This article provides a short review of the CGH technique and its pitfalls, summarizes the current CGH-related data on pediatric brain tumors and muses on the future of CGH.

Adolescent↗
PubMed1987

Inflammatory sensory polyradiculopathy and reactivated peripheral nervous system infection in a genital herpes model.

To study effects of herpesvirus reactivation on the nervous system, mice with latent genital herpes simplex virus type 2 (HSV-2) infections were immunosuppressed. Reactivated infection was detected by virus isolation or by antigen screening in histological sections of spines that contained cords, roots, and dorsal root ganglia. In ganglia, viral antigen was restricted to 2 distinct groups at T9-L2, and L6-S2 levels. In some ganglia, antigen was found in up to 4% of non-contiguous neurons, in their axons, and in endoneurial and satellite cells. Nerve roots distal to ganglia contained a few antigen-positive endoneurial cells and axons, but convincing antigen was not seen in proximal roots. Rare foci of anterior horn cells in the lower cord were the only central sites found to contain antigen. Comparison of antigen-containing ganglionic neuron counts to vaginal culture data indicate that peripheral virus shedding may depend on the number of neurons with reactivated infection. In non-immunosuppressed, latently infected mice, virus recovery was restricted to ganglionic explants from lower thoracic and lumbosacral regions; these ganglia contained no infectious virus in homogenates and no detectable antigen. These mice had an inflammatory polyradiculopathy in a similar distribution to virus found in latent and reactivated infection. The data show that genital HSV-2 infection can result in more extensive ganglionic latency and peripheral nervous system disease than has previously been recognized. Immunosuppression leads to reactivation and widespread, anatomically restricted antigen expression in many ganglia, consistent with the innervation of the genitourinary tract. Decalcified spine preparations provide a sensitive and simple way to detect virus reactivations and disease in these neural tissues.

Animals↗