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H Aldskogius

Publications and source records attributed to H Aldskogius.

At least 109 records · Page 6Linked to original sources
PubMed1986

Collateral sprouting of sensory axons in the glabrous skin of the hindpaw after chronic sciatic nerve lesion in adult and neonatal rats: a morphological study.

The anterograde transport of wheat germ agglutinin-horseradish peroxidase conjugate was used to study the normal distribution of sensory nerve axons in the plantar skin of the rat hindlimb and at various times after chronic sciatic nerve injury in adult and neonatal rats. In adults, thin saphenous nerve axons were found in a small area laterally to the normal saphenous nerve territory 2-24 weeks after sciatic nerve lesion. In neonatal rats, at 6 and 10 weeks after sciatic nerve injury thin saphenous nerve axons were found almost or all over the sole of the foot, respectively, and in all 5 toes. At longer survival times, the area innervated by saphenous nerve axons became smaller. However, this area was now occupied by thin, as well as coarse axons. When adult animals were subjected to saphenous nerve crush simultaneously with the sciatic nerve lesion, thin, as well as coarse, nerve axons were found laterally to the normal saphenous nerve territory. The findings indicate that thin cutaneous sensory axons of adult mammals can extend collateral sprouts in glabrous skin for a short distance. This capacity appears to be greater in neonatally lesioned animals, where it is present for coarse cutaneous sensory axons as well. However, after neonatal nerve injury collateral sprouts seem to disappear from the initially most distally reinnervated area. Regenerating sensory axons in adult rats seem to have a greater capacity for collateral sprouting than intact axons. Coarse and thin cutaneous sensory axons could be found in this instance. In all instances a great part of the plantar skin remained denervated, suggesting that there is an upper limit for the territory which can be maintained by cutaneous sensory neurons reinnervating glabrous skin.

Age Factors↗
PubMed1986

Selective reinnervation of somatotopically appropriate muscles after facial nerve transection and regeneration in the neonatal rat.

The organization of the facial motor nucleus (FMN) has been examined after transection and regeneration of the facial nerve (FN) in neonatal and adult rats. In one series of experiments, horseradish peroxidase (HRP) was applied bilaterally to the superior or inferior buccal ramus 5 months after neonatal FN transection. In another series of experiments, wheat germ agglutinin-horseradish peroxidase conjugate was injected in selected vibrissae follicular muscles on both sides in animals surviving 5 months after FN transection at the neonatal or adult stage. The number and distribution of HRP-labeled cell bodies in the FMN after regeneration was compared with the contralateral side. On the uninjured side, labeled neurons were somatotopically organized. Ipsilateral to nerve injury the number of labeled cells was markedly reduced after neonatal nerve transection, but somatotopy was preserved. However, after nerve lesion at the adult stage, no significant loss of motoneurons occurred, but motor nucleus somatotopy was not maintained. Two alternative principal explanations are proposed for the re-establishment of the normal somatotopy after neonatal injury: that regenerating axons grow in a random fashion but inappropriate connections are subsequently eliminated or that regenerating axons of surviving neurons immediately follow a pathway leading to the appropriate muscle.

Aging↗
PubMed1986

Effect of axotomy on perineuronal glial cells in the hypoglossal and dorsal motor vagal nuclei of the cat.

An approximate twofold increase in microglial cell densities occurred in the hypoglossal and dorsal motor vagal nuclei of the cat after transection of their respective nerves. The densities of astrocytes and oligodendrocytes were unaffected. A significant loss of neurons was demonstrated in both nuclei. These findings indicate that a perineuronal microglial cell reaction occurs in craniomotor nuclei of the cat following nerve transection, but to a considerably lesser extent than in rats and rabbits. We suggest that the different glial response after nerve transection compared with nerve crush in the cat may be related to differences in the degree of axotomy-induced neuronal degeneration.

Animals↗
PubMed1986

Labeling of cutaneous sensory nerve endings with axonally transported horseradish peroxidase and wheat germ agglutinin-horseradish peroxidase conjugate: a methodological study in the rat.

Practical aspects on the use of horseradish peroxidase (HRP) and wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) to trace peripheral cutaneous nerve endings have been studied. The parameters studied included application site of the tracer, post-application survival time, tracer concentration and tracer volume. These parameters were examined in the glabrous skin of the rat hindpaw. The best results were obtained with injections of 1 microliter WGA-HRP (20 micrograms/microliter) in dorsal root ganglia innervating the examined cutaneous region and a postinjection survival time of 18-36 h. With this approach extensive and heavy labeling was achieved of epidermal nerve endings, nerve endings in Merkel cell-neurite complexes and Meissner corpuscles. Useful, but less extensive labeling of these types of peripheral nerve endings, was obtained with injections of HRP in the lumbar spinal cord dorsal horn.

Animals↗
PubMed1986

Primary sensory afferents in the inferior mesenteric ganglion and related nerves of the guinea pig. An experimental study with anterogradely transported wheat germ agglutinin-horseradish peroxidase conjugate.

Peripheral visceral afferents in the guinea pig were labeled by injections of wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) into the L2 and L3 dorsal root ganglia bilaterally. After anterograde transport of the tracer the following areas were examined for the presence of HRP-labeled fibers: the inferior mesenteric ganglion (IMG), the inferior mesenteric artery (IMA) with surrounding tissue, the hypogastric nerves, parts of the descending and sigmoid colon as well as the urinary bladder. Large numbers of heavily labeled fibers were found in the IMG, in the colonic nerves around the IMA and in the hypogastric nerves. In the IMG, profiles suggestive of being labeled axon terminals were observed. Labeled fibers were observed in the muscle layers of the colon and in the bladder wall. The results show that anterograde tracing with WGA-HRP can be used successfully in analyzing the morphology and structural organization of visceral afferents in the periphery.

Afferent Pathways↗
PubMed1985

A morphological study of glial cells in the hypoglossal nucleus of the cat during nerve regeneration.

The cat hypoglossal nerve and nucleus have been used as a model for the study of the occurrence and time course of modifications in the size and composition of the perineuronal glial cell population as they relate to cytological changes in the nerve cell body and the initiation and progress of axon regeneration. Animals were killed at 2, 5, 10, 20, 35, 65, and 115 days after crush injury to the hypoglossal nerve. At 5 days after surgery, growth cones and regenerating unmyelinated axons were present at the lesion site, but no conspicuous changes were apparent in the nerve cell bodies. At 10 days after surgery, the granular endoplasmic reticulum was disaggregated and depleted. The elongation phase appeared to be completed at 20 days, as judged by the bilateral retrograde labeling of the hypoglossal nuclei with horseradish peroxidase. By 35 days, the cytoarchitecture of the nerve cell bodies and maturation of axons, as determined by a comparison of the relative frequency distribution of cross sectional areas proximal and distal to the lesion, were completely restored. Comparative quantitative light microscopic examination of the hypoglossal nuclei of intact and experimental animals failed to reveal any statistically significant differences in the total number of glial cells, number of glial cells/unit area of neuropil, or relative proportions of glial cell types at any of the postoperative time intervals. Moreover, electron microscopic quantitation of the microglial cell population did not reveal any significant alterations in the number, density, location, or morphology of these cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

The effect of sciatic nerve transection on myelinated fibers in the L5 dorsal root and lumbar dorsal column. A Marchi study in the rat.

The occurrence of Marchi-positive structures (MPS) in the L5 dorsal root and lumbar dorsal column was examined 1-18 weeks after unilateral sciatic nerve transection in rats, and compared to the occurrence of MPS during Wallerian degeneration seen after transection of L4 and L5 dorsal roots. There was an increasing number of MPS centrally to the junction between the peripheral (PNS) and central nervous system (CNS) and in the lumbar dorsal column ipsilateral to sciatic nerve transection throughout the examined time period. In the portion of the root distal to the PNS-CNS junction MPS were rare before 12 weeks postoperatively after which time small groups of MPS appeared. At all stages the incidence of MPS was just a fraction of that seen during Wallerian degeneration. From these observations it is inferred that few ganglion cells with myelinated central processes undergo complete disintegration after peripheral nerve transection. In addition, some of the myelinated central ganglion cell processes appear to be more severely affected proximal to the PNS-CNS junction than distally to it.

Animals↗
PubMed1985

The reaction of primary sensory neurons to peripheral nerve injury with particular emphasis on transganglionic changes.

This paper reviews light- and electron microscopic, histochemical and physiological evidence which demonstrate that peripheral nerve injury in mammals is followed by profound structural and functional changes in the central terminals of the affected primary sensory neurons. Available evidence indicates that at least some of these so-called transganglionic changes are the result of ganglion cell degeneration and death, although other mechanisms are probably in effect as well. Existing data suggest that this ganglion cell death does not effect all types of ganglion cells equally, but do not permit a clearcut answer to the question of which kinds of ganglion cells are affected more than others. Results from studies with microtubule inhibitors and antibodies to nerve growth factor are compatible with the notion that depletion of retrogradely transported trophic factors is involved in the production of certain transganglionic changes. This issue needs further examination, however. Physiological studies indicate marked alterations in certain primary afferent synaptic connections after peripheral nerve lesions. So far, these changes have not been satisfactorily correlated with the structural changes induced by similar lesions. Further studies on the structural and functional response of primary sensory neurons to peripheral nerve injury are likely to contribute to the understanding of the frequent failure to regain normal sensory functions after peripheral nerve lesions in man, as well as of the basic aspects of lesion-induced changes in general in the peripheral and central nervous system.

Acid Phosphatase↗
PubMed1984

Evidence for a sympathetic component in motor branches of the facial nerve: a horseradish peroxidase study in the cat.

The retrograde transport of horseradish peroxidase (HRP) was used to examine the location of sympathetic ganglion cells with axons in facial motor branches of the cat. Large numbers of HRP-labeled neurons were observed in the rostro-anterior part of the superior cervical ganglion. In addition, some labeled neurons were found in the cervical sympathetic trunk, the accessory cervical, middle cervical and stellate ganglia.

Adrenergic Fibers↗
PubMed1984

Intercostal nerve transection and its effect on the dorsal root ganglion. A quantitative study on thoracic ganglion cell numbers and sizes in the rat.

The effect of intercostal nerve transection on the number and size distribution of thoracic spinal ganglion cells has been investigated and correlated with transganglionic degeneration (TGD) in the spinal cord dorsal horn. Unilateral transections were made of 3 or 11 consecutive intercostal nerves. Twenty to 180 days later the animals were perfused and relevant ganglia from both sides embedded in resin, serially sectioned and stained. Counts of neuronal nucleoli were made and perikaryal areas of ganglion cells measured. The number of neurons was significantly reduced on the operated side 20 days postoperatively. The cell loss increased slightly to about 35% with longer survival times. Analysis of cell size spectra showed a bilaterally symmetrical picture in normal animals. No distortions of the cell size spectrum were observed at 20 to 70 days after nerve transections. Transganglionic degeneration was found in the dorsal horn from 20 to 70 days postoperative survival, but not at 180 days. The findings indicate that TGD in the dorsal horn is related to a loss of ganglion cells in the corresponding spinal ganglion. There does not seem to be a preferential loss of any particular size class of cells.

Animals↗
PubMed1984

Effect of nerve section on perineuronal glial cells in the CNS of rat and cat.

The effect of axotomy on the numbers and density of perineuronal cell populations was evaluated in rats, cats and kittens. Cats were sacrificed at different postoperative time intervals two through 90 days after unilateral plexotomy. Kittens (6-10 weeks of age) were subjected to the same surgical procedure and sacrificed one through 28 days after surgery. Rats were sacrificed 10 and 15 days after unilateral section of the brachial plexus or at 7 or 10 days after section of the left hypoglossal nerve. A marked increase in the total number and density of perineuronal cells occurred in the rat ventral horn 10 and 15 days after axotomy. A similar response was noted in the rat hypoglossal nucleus 7 and 10 days after neurotomy. In contrast, no significant change in these parameters was observed in the ventral horns of cats and kittens at any of the postoperative time intervals. Although quantitatively demonstrable increases in the perineuronal cell populations occur in the ventral horns and hypoglossal nuclei of rats, similar modifications do not occur in the cat following axon injury. These findings suggest that evolutionary modifications may have occurred in how perineuronal glia respond to peripheral axon injury.

Animals↗
PubMed1984

Axon reaction in hypoglossal and dorsal motor vagal neurons of adult rat: incorporation of [3H]leucine.

Pairs of adult rats received [3H]leucine (i.p., 5 microCi/g body weight) 0.25, 1, and 16 h before killing and zero (unoperated control animals) and 1 to 164 days after unilateral cervical vagotomy and hypoglossal neurotomy. Grain counts and morphometric measurements were made on axotomized and uninjured neurons in histoautoradiographs of the medullary nuclei. Axotomized hypoglossal neurons, which largely survive the injury, both enlarged and incorporated increased amounts of tritiated leucine at each labeling interval, 3 through 28 days postoperatively. In the vagal dorsal motor nucleus (DMN), axotomized cells, which frequently die after neurotomy, enlarged slightly through 28 days postoperatively, then atrophied; DMN neurons increased amino acid uptake for a shorter period (days 7 through 14) than hypoglossal neurons. This increase achieved statistical significance only when the labeling intervals were 0.25 or 1.0 h. Neurons of the DMN contralateral to vagotomy also enlarged. Axotomized DMN neurons did not sustain increased protein synthesis as long as their hypoglossal counterparts and seemed to fail to increase synthesis of structural proteins with long half-lives (16-h labeling interval). The frequently necrobiotic response of axotomized DMN neurons may relate to these phenomena. From these and earlier results, we conclude that axon reaction appears to differ fundamentally in peripheral and central neurons. This difference may have significance for research on regeneration in the central nervous system.

Animals↗
PubMed1984

A procedure for studying the organization of peripheral nerves with horseradish peroxidase demonstrated on the facial and hypoglossal nerves in the rat.

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.

Animals↗
PubMed1983

Preferential loss of unmyelinated L7 dorsal root axons following sciatic nerve resection in kittens.

Some time following sciatic nerve resection in kittens the number of L7 spinal ganglion neurons appears to have decreased more than the number of L7 dorsal root axons, and the proportion of unmyelinated axons is unchanged. The present results show that removal of the sciatic neuroma results in a clearly subnormal proportion of unmyelinated axon profiles. This indicates that recurrent sprouts from the neuroma had entered the dorsal root and that spinal ganglion neurons with unmyelinated axons are preferentially lost after axotomy in kittens.

Animals↗
PubMed1983

Effects of sciatic nerve resection on L7 spinal roots and dorsal root ganglia in adult cats.

The size, distribution, and number of nerve fibers and neuronal perikarya in the L7 spinal roots and ganglia of adult cats were examined 35, 90, and 190 days after ipsilateral sciatic nerve resection. With increasing survival time the size spectra of myelinated ventral root nerve fibers showed a progressive flattening of the alpha peak. In the dorsal roots the myelinated fiber size distribution exhibited a marked shift toward smaller sizes. The reduction in the proportion of large myelinated axons was particularly evident in the dorsal roots. Less clearcut changes were found in the size distribution of spinal ganglion neuronal perikarya. No significant loss of axons could be detected in ventral or dorsal roots. There was, however, a marked reduction in the number of dorsal root ganglion neurons. This discrepancy suggested the possibility that an initial loss of dorsal root axons was concealed by recurrent sprouting of axons from the proximal nerve stump. However, neuroma excision 90 days after nerve resection did not lead to any reduction in dorsal root axon numbers. Thus, any ingrowth of new axons to the dorsal root should occur from levels proximal to the neuroma. In comparison with previous findings in kittens, peripheral nerve resection in adult cats had significantly smaller effects on sizes and numbers of spinal root nerve fibers as well as of dorsal root ganglion neurons. Therefore, the potential for restitution of the peripheral innervation by axon regeneration appeared to be basically greater in mature than in immature animals.

Animals↗
PubMed1983

Effects of sciatic nerve crush on the L7 spinal roots and dorsal root ganglia in kittens.

The number and size distribution of axons and neurons were examined in the L7 spinal roots and ganglia of kittens 14 to 220 days after early postnatal sciatic nerve crush. The results show that motoraxons in the ventral root as well as axons and perikarya of sensory neurons in the dorsal root remained growth-retarded throughout the examined period. This was most evident in the dorsal root. Both ventral and dorsal roots showed some loss of myelinated axons, but this was only half that previously observed after sciatic nerve resection. Whereas in the dorsal roots and dorsal root ganglia the loss seemed to be nonselective with respect to size, axons in the gamma range were primarily affected in the ventral roots. In the dorsal roots the proportion of unmyelinated axons was comparable with controls but in the ventral roots it was somewhat elevated. In most cases the loss of dorsal root ganglion neurons was relatively greater than the decrease of dorsal root axons.

Animals↗
PubMed1983

Uptake and transport of exogenous macromolecules from the tongue to the facial nerve complex in the rat.

According to a current theory about the pathogenesis of Bell's palsy, the motorfibers of the facial nerve are affected by a viral neuropathy, transmitted to the facial nerve via the axons of the chorda tympani nerve. We have used horseradish peroxidase (HRP) to test to what extent and under what conditions uptake and transport of macromolecules can take place from the tongue. When HRP was applied directly onto the mucosa, no labeling was observed. However, when applied to localized superficial lesions of the epithelium or injected into the tongue, HRP is transported retrogradely to the geniculate and trigeminal ganglia, superior salivatory and hypoglossal nuclei. Injection of HRP resulted in many more labelled cells as well as fiber labeling in the peripheral nerves, in the solitary and spinal trigeminal nuclei. The findings show that even after a minor-superficial lesion in the tongue, exogenous macromolecules are taken up and transported to the intratemporal portion of the facial nerve as well as other cranial nerves. These findings are compatible with the theory that Bell's palsy is a neuropathy caused by neurotropic viruses spread via the chorda tympani.

Animals↗