Papers by Håkan Aldskogius
Experimental Neurology, Mar 1, 1993
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Journal of the autonomic nervous system, Feb 1, 1987
Preganglionic sympathetic neurons in the guinea pig were labeled by injections of wheat germ aggl... more Preganglionic sympathetic neurons in the guinea pig were labeled by injections of wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) into the L2 and L3 spinal cord segments. After anterograde transport of the tracer the following areas were examined for the presence of HRP-labeled fibers: the inferior mesenteric ganglion (IMG), the pelvic ganglia, the hypogastric and colonic nerves. In the ganglia labeling appeared predominantly as clusters of varicose-like profiles suggestive of being axon terminals. Particularly in the pelvic ganglia, these profiles appeared to surround the contours of some of the ganglion cell bodies. Numerous HRP-positive fibers were present in the hypogastric nerves, but only occasional fibers were observed in the colonic nerves. The pattern of labeling differed markedly from that described previously after anterograde transport of WGA-HRP in sensory fibers of the IMG, hypogastric and colonic nerves. Furthermore, the results from this and the previous study show that anterograde tracing with WGA-HRP can be a useful means for analyzing the structural organization of various fiber inputs to autonomic ganglia.
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Restorative Neurology and Neuroscience, 1992
Clinical and experimental observations have demonstrated that peripheral nerve transection genera... more Clinical and experimental observations have demonstrated that peripheral nerve transection generally results in lasting disturbed sensory discrimination whereas nerve crush is followed by more or less complete functional restoration. This has been explained by an increased misdirection of regenerating fibers after transection as compared to crush injury. In the present study, sequential double-labeling was used to investigate the relative proportions of peripherally misdirected sensory fibers in the sural and tibial nerve branches after crush or transection of the parent sciatic nerve in the rat. Control experiments showed that 0.21% ± 0.12 (mean ± S.D.) of all labeled tibial and sural neurons normally send axons to both nerves. After sciatic nerve crush or transection, 1.31% ± 0.78 and 3.79% ± 3.01, respectively, of all labeled tibial and sural axons were double-labeled indicating previously sural axons now having an axon in the tibial. Statistically significant differences in the percentages of bidirectional sciatic sensory neurons were found between the normal controls and after crush injury (P < 0.01) or transection injury (P < 0.001), respectively, but not between transection and crush (P > 0.05). The results indicate that the number of sensory neurons having an axon in two peripheral nerves is normally very small, that a substantial number of sensory axons become misdirected after both crush and transection with resuture, and that the number of misdirected fibers in the major sciatic branches after these types of injury is similar.
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Upsala Journal of Medical Sciences, 2007
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Molecular and Chemical Neuropathology, 1995
In a previous study, we found immunoreactivity for complement factors C3, C3d, and C4d, as well a... more In a previous study, we found immunoreactivity for complement factors C3, C3d, and C4d, as well as endogenous IgG in the hypoglossal nucleus following hypoglossal nerve transection, suggesting that activation of the complement cascade had taken place in the vicinity of the axotomized motorneurons. In the present study, we found increased immunoreactivity for complement factor C1 and C1q in reactive microglia, indicating an increased potential for initiation of the classical pathway by binding of IgG to C1q. Furthermore, we found immunoreactivity for C9, which contributes to the formation of C5b-9, the final lytic product of the complement cascade close to the axotomized neurons and perineuronal glia. In addition, immunoreactivity and mRNA labeling of sulfated glycoprotein (SGP-2), a putative complement inhibitor, was increased in a subpopulation of the axotomized motorneurons. SGP-2 immunoreactivity was also increased in astroglial cells ipsilateral to the nerve injury. The results lend further support to the hypothesis that the complement cascade is activated in the vicinity of axotomized neurons, which in turn may be protected by complement inhibitors. The balance between activation of complement and complement inhibitors might have an impact on the degenerative components of the axon reaction and, in particular, the events leading to nerve cell death.
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Lakartidningen, 2000
Disturbances in the normal homeostasis of the central nervous system induce a localized activatio... more Disturbances in the normal homeostasis of the central nervous system induce a localized activation of microglia. This activation serves to isolate pathological processes from surrounding, intact nervous tissue. Concomitantly, healthy or minimally damaged nerve cells nearby may be negatively influenced by potent molecules released by activated microglia. This situation appears to exist e.g. in ischemia, multiple sclerosis and Alzheimer's disease. Pharmacologic regulation of microglial activity is therefore a rational approach to treatment of many central nervous system disorders.
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Brain Damage and Repair, 2004
ABSTRACT Axonal disintegration is a major cause of neurological disease. Normal axonal integrity ... more ABSTRACT Axonal disintegration is a major cause of neurological disease. Normal axonal integrity is maintained by the combination of intrinsic metabolic activities, delivery of molecules via intra-axonal transport and support from external cellular and extracellular sources. Trauma, ischemia, toxic agents, metabolic disturbances, inflammatory conditions and inadequate axon-glial interactions result in axonal disintegration. This process is characterized by breakdown of the axonal cytoskeleton, mitochondrial failure, and the accumulation of abnormal proteins and protein complexes. Intra-axonal rise in calcium above physiological levels appears to be a key factor in initiating these events. Axonal dysfunction can be attenuated by administration of calcium blockers, a variety of growth factors, immune suppressants, anti-inflammatory agents, as well as free radical scavengers. The recent identification of a gene, which “protects” axons from undergoing degeneration, provides a basis for a genetic approach to the treatment of neurological disorders caused by axonal disease or trauma.
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ORL, 1984
The intraaxonal transport of horseradish peroxidase, applied to the proximal stump of different t... more The intraaxonal transport of horseradish peroxidase, applied to the proximal stump of different transected hypoglossal and facial nerve branches, was used to label fibers in the hypoglossal main trunk and in the intratemporal portion of the facial nerve in the rat. By using tetramethylbenzidine as a substrate, numerous heavily labeled fibers are obtained. In longitudinal sections the arrangement of fibers can be studied for long distances. From these sections, sites of specific interest can be further examined in transverse-like reconstructions of the nerve. Thus, the procedure described offers a convenient way of analyzing the intrinsic organization of peripheral nerves.
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Mechanoreceptors, 1988
Following injury to peripheral sensory nerves residual functional defects and abnormal sensations... more Following injury to peripheral sensory nerves residual functional defects and abnormal sensations are common consequences (Sunderland, 1978). An understanding of the mechanism(s) for these disturbances requires a detailed knowledge of how these nerve lesions affect the various components in the somatosensory system from receptor to cerebral cortex.
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Journal für Hirnforschung, 1989
Around 24 hours following neonatal lumbar dorsal root transections in kittens, the disintegration... more Around 24 hours following neonatal lumbar dorsal root transections in kittens, the disintegration of myelinated axons in the lumbar dorsal column was accompanied by the appearance of numerous pyknotic profiles. These profiles were found to represent glial cells in various stages of degeneration. At earlier and later postlesion survival times similar profiles were rare or absent. It is suggested that acute changes in the physical and/or chemical properties of myelinated axons undergoing Wallerian degeneration during a particular developmental period is incompatible with survival of certain types of glial cells. These cells may be oligodendrocytes and/or so-called type II astrocytes.
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Journal of the peripheral nervous system : JPNS, 1999
We have examined the role of complement component 5 (C5) in peripheral nerve fiber degeneration a... more We have examined the role of complement component 5 (C5) in peripheral nerve fiber degeneration and regeneration, as well as in glial and neuronal cell responses in the central nervous system (CNS). Adult congenic mice lacking C5 (C5(-)) and the corresponding normal strain (C5(+)) were used. Macrophage recruitment as well as axonal and myelin sheath elimination were delayed from 1 to 21 days postinjury in C5(-) mice compared to the C5(+) group after sciatic nerve crush. Despite this, recovery of motor function was not delayed. In the CNS, microglial cells and astrocytes responded in the same way from 3 to 21 days after sciatic nerve injury in C5(-) and C5(+) mice, and the extent of neuron death following hypoglossal nerve avulsion was the same in both groups. These findings suggest that C5 and/or its derivatives play an important role in initiating the recruitment of macrophages to the injured nerve and, probably indirectly, in early remyelination of regenerating axons, but does not...
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SpringerReference
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Teaching and Learning in Medicine, 1999
... Problem 7 Billy Rubin comes to your office. ... As part of your examination you try to palpat... more ... Problem 7 Billy Rubin comes to your office. ... As part of your examination you try to palpate BillyRubin's liver and gallbladder. (1p) Mark the projections of the liver and gall-bladder on the abdominal surface on the sketch of thebodyinFigure1[notincludedinthisarticle]. ...
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Neuroscience, 1995
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NeuroReport, 1994
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Neurobiology of Aging, 1996
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Journal of Neurotrauma, 1999
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Journal of Neuroscience Methods, 1986
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Journal of Comparative Neurology, 1981
The right/left ratio for the number of neurons in individual pairs as well as series of pairs of ... more The right/left ratio for the number of neurons in individual pairs as well as series of pairs of normal rat and guinea pig thoracic dorsal root ganglia have been investigated. After perfusion of the animals with aldehyde fixatives, the 13 pairs of thoracic ganglia were embedded in resin, serially sectioned, and stained with azur methylene blue. Counts of neuronal nucleoli (with correction for possible split nucleoli) were used as an indicator of the number of neurons in each ganglion. In individual pairs the right/left difference varied between 0 and 47% in the rat and 0 and 26% in the guinea pig. There appeared to be no particular level with a preference for large right/left differences. However, when the total number of neurons from the 13 ganglia on one side were compared with the corresponding figure from the other side, the right/left differences were reduced to less than 3% in the rat and less than 2% in the guinea pig. These results show that the organization of the thoracic ...
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Papers by Håkan Aldskogius