The distribution of the proteoglycan FORSE-1 in the developing mouse central nervous system.

Glycosylation is a major post-translational modification in which a carbohydrate known as a glycan is enzymatically attached to target proteins which regulate protein folding and stability. Glycans are strongly expressed in the developing nervous system where they play multiple roles during development. The importance of these glycan epitopes in neural development is highlighted by a group of conditions known as congenital disorders of glycosylation which lead to psychomotor difficulties, mental retardation, lissencephaly, microencephaly and epilepsy. One of these glycan epitopes, known as Lewis X, is recognised by the FORSE-1 antibody and is regionally expressed in the developing nervous system. In this study, we report the regional and temporal expression patterns of FORSE-1 immunolabelling during the periods of neurogenesis, gliogenesis and axonogenesis in developing mouse nervous system. We demonstrate the localisation of FORSE-1 on subsets of neuroepithelial cells and radial glial cells, and in compartments corresponding to axon tract formation. These spatial, temporal and regional expression patterns are suggestive of roles in the determination of different cell lineages and in the patterning of white matter during development, and help provide insights into the neuroanatomical regions affected by congenital disorders of glycosylation.

A cadaveric study of aortic arch variation in an Irish population.

AIM: The aim of this study is to investigate the incidence of variation in the branching pattern of aortic arch (AA) vessels in an Irish population. METHOD: A cadaveric study of 24 subjects was conducted. The vessels of the AA were identified, their branching patterns were noted and photographed and the following measurements were recorded: the angle of the AA to the coronal plane, the distance from the midline to the brachiocephalic trunk (BCT); the left common carotid artery (LCC) ; the left subclavian artery (LSC), the distance between the BCT and the right subclavian artery (RSC); the RSC and the right vertebral artery (RVA), and between the LSC and left vertebral artery (LVA). RESULTS: The 'normal' branching pattern (BCT, LCC, LSC) was observed in 79%. Thirteen percent had a two-branched AA (bovine variant), while the remainder had an aberrant left vertebral artery (LVA) originating from the AA. The mean distances from the midline to the BCT, LCC and LSC were 9.1, 10.8 and 21.4 mm, respectively. Mean distance from BCT to RSC was 34.09 mm. The mean distance from LSC to LVA was 39.79 mm, and the mean distance from RSC to RVA was 23.38 mm. The mean angle of the AA to the coronal plane was 59.02°. CONCLUSION: This is the first study documenting the rates of variation of the AA in Ireland. Variation of AA branching is of radiological and surgical significance, particularly in the diagnosis and treatment of thoracic and head and neck diseases. Awareness of these variations is particularly relevant for interventionalists who access these vessels during endovascular surgery.

Towards an understanding of semaphorin signalling in the spinal cord.

Semaphorins are a large family of proteins that are classically associated with axon guidance. These proteins and their interacting partners, the neuropilins and plexins are now known to be key mediators in a variety of processes throughout the nervous system ranging from synaptic refinement to the correct positioning of neuronal and glial cell bodies. Recently, much attention has been given to the roles semaphorins play in other body tissues including the immune and vascular systems. This review wishes to draw attention back to the nervous system, specifically focusing on the role of semaphorins in the development of the spinal cord and their proposed roles in the adult. In addition, their functions in spinal cord injury at the glial scar are also discussed.