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Y Olsson

Publications and source records attributed to Y Olsson.

At least 55 records · Page 3Linked to original sources

The angiopathy of subcortical arteriosclerotic encephalopathy (Binswanger's disease): immunohistochemical studies using markers for components of extracellular matrix, smooth muscle actin and endothelial cells.

A pronounced obliterative microangiopathy of the deep cerebral white matter is one of the cardinal features in classical cases of Binswanger's encephalopathy. We have characterised the alterations taking place in the intima, media and adventitia of obliterated arterial vessels in seven autopsy cases of this encephalopathy. The adventitia of fibrosed vessels showed immunoreactive material indicating a marked deposition of normally occurring collagen types, i.e. I, III and V. Similar deposits occurred in degenerated parts of the media. Two of the cases had, in addition, signs of collagen type VI-immunoreactive material in the adventitia and media. The elastica of arteries was often split and formed multiple layers. The inner part of the blood vessel walls contained immunoreactivity to collagen type IV and laminin, indicating increased amounts of basal lamina components. Using actin immunostaining the fibrosed arterial vessels showed a severe reduction of smooth muscle cells of the media. However, many terminal arterioles presented a marked actin immunostaining, possibly indicating hypertrophy of smooth muscle cells. The endothelial cell layer did not show any changes with regard to expression of glucose transporter 1, factor VIII, Ulex europaeus agglutinin I and CD34. Degeneration of the media associated with depositions of collagens type I, III, IV, V and possibly type VI, as well as other components of extracellular matrix, will jeopardize the regulatory functions of the afflicted vessels. The maintenance of the endothelial lining of the obliterated vessels probably counteracts thrombosis in the vessels.

Adult↗

Expression of various TGF-beta isoforms and type I receptor in necrotizing human brain lesions.

It is known that transforming growth factor beta (TGF-beta) is involved in the modulation of cell growth, differentiation, and repair following injury. We performed an immunohistochemical study of human brain autopsy and biopsy material for the expression of TGF-beta isoforms beta 1, beta 2 and beta 3, and TGF-beta receptor (T beta R) type I in different cells of necrotizing lesions such as infarction and abscess, and compared them with controls. Various cell types, both inside and in the proximity of lesions, showed immunoreactivity indicating the presence of all three isoforms. Significant values of immunoreaction for various TGF-beta s and T beta R-I were observed in cells such as astrocytes, macrophages, neurons, microvascular endothelial cells, and granulocytes. In the control cases, comprising biopsy material without necrotizing lesions, a prominent TGF-beta 2 immunoreactivity was observed in glial cells and neurons. TGF-beta 1 and TGF-beta 3 reactivity in controls, when compared with TGF-beta 2, was less. T beta R-I antiserum showed clear and distinct signals in the same type of cells as for TGF-beta s in the necrotizing lesions with varying values of significance. Our findings suggest that TGF-beta s and their receptor type I are involved in reactive processes around necrotizing human brain lesions like glial and macrophage responses, angiogenesis, and deposition of extracellular matrix.

Adult↗

Up-regulation of intercellular adhesion molecule 1 in cerebral microvessels after cortical contusion trauma in a rat model.

A study was made on the expression of the intercellular adhesion molecule 1 (ICAM-1) in cerebral microvessels after cortical contusion trauma of the rat brain. The trauma was produced by a free-falling weight on the exposed dura of one fronto-parietal lobe. Immunohistochemistry was done on cryostat sections using a monoclonal antibody and the reaction product was visualized using the avidin-biotin-peroxidase complex method. Control and sham-operated rats showed immunostaining of some penetrating arteries of the cerebral cortex, the epithelial cells of the choroid plexus and occasional microvessels of the brain parenchyma. The same pattern of immunostaining was seen in rats that were subjected to trauma and killed after 30 min. All rats with contusion trauma that were allowed to survive for 6-72 h showed a substantial increase in the number of immunostained capillaries throughout the site of the lesion. The ipsilateral hippocampus showed a mild to moderate increase in the number of immunostained microvascular profiles. This phenomenon was also present in the lateral thalamus of some rats. The staining was seen as an uninterrupted line at the position of the endothelial cells, indicating an upregulation of this adhesion molecule after brain trauma. Up-regulation of ICAM-1 is a well-known phenomenon in inflammatory and ischemic lesions of the brain but has not previously been described in detail in traumatic brain injury. ICAM-1 may be involved in the production of several post-traumatic events such as leukocyte adhesion, microcirculatory disturbances and edema formation.

Animals↗

Hematogenous metastases of the human brain--characteristics of peritumoral brain changes: a review.

The brain is an important site of hematogenous metastases from malignant tumors in other organs. The effects on the brain is a combination of tissue destruction induced by invading tumor cells and reactive alterations occurring around the metastases. This review focuses on neuropathological changes around hematogenous metastases of the human brain. The peritumoral brain parenchyma shows structural and functional changes of the intracerebral microvessels and edema. The endothelial cells of peritumoral microvessels express glucose transporter protein (GLUT 1) in the same way as the normal brain. Reduction in immunostaining to GLUT 1 may occur in the microvessels located within the metastases. This would indicate abnormalities of the blood-brain barrier in tumor vessels but normal barrier function in the peritumoral region. Reactive astrocytes and activated microglial cells are both involved in the process of peritumoral gliosis. Activated glial cells produce numerous biological active compounds including endothelin-1 which after release from such cells can influence the structure and function of the peritumoral brain tissue. Lesions of oligodendrocytes and edema may be implicated in myelin degeneration. Finally, metastases will induce axonal and neuronal injuries as indicated by a recent study on expression of beta-amyloid precursor protein (beta APP) in reactive axonal swellings.

Axons↗

Pretreatment with alpha-phenyl-N-tert-butyl-nitrone (PBN) improves energy metabolism after spinal cord injury in rats.

We evaluated in rats, the effect of the spin trap alpha-phenyl-N-tert-butyl nitrone (PBN) on energy metabolism after severe spinal cord injury (SCI). A laminectomy of vertebrae Th7 and Th8 was made. A probe was inserted in a dorsal horn, and microdialysis was performed for 1.5 h before and 4 h after applying severe compression (4.5 g/mm2) for 5 min. Thirty minutes before trauma 30-mg/kg PBN or saline was given intravenously and a second dose of 10 mg/kg after 3 h. Microdialysis samples were collected at intervals of 10 min and analysed by high performance liquid chromatography. As reported previously there was a severalfold rise of lactate after trauma. The mean level of lactate was consistently lower in animals pretreated with PBN, but the difference was statistically significant between the groups only at 200 min after trauma. Lactate normalized more rapidly in PBN pretreated animals. In saline-treated rats, hypoxanthine quickly rose and reached a maximum 23 times above basal level 20 min after trauma, while the rise was 14 times in PBN pretreated rats. The increase of hypoxanthine was significantly lower and normalized more rapidly in PBN pretreated animals. This study suggests that PBN pretreatment attenuates lactic acidosis and improves energy metabolism after severe SCI. The effect may, at least partly, reflect amelioration of radical induced mitochondrial dysfunction.

Animals↗

Effects of moderate hypothermia on extracellular lactic acid and amino acids after severe compression injury of rat spinal cord.

We evaluated in rats, the effect of moderate hypothermia (30-31 degrees C) on extracellular levels of amino acids, with special emphasis on the excitatory amino acids (EAAs) glutamate and aspartate, lactate and pyruvate, after severe spinal cord compression. A laminectomy of Th7 and Th8 was made. A probe was inserted in a dorsal horn and microdialysis was performed for 1.5 h before and 4 h after applying severe compression for 5 min. Dialysate samples were collected at intervals of 10 min and analyzed by high-performance liquid chromatography. In normothermic (37.5 degrees C) animals there was a several-fold rise of glutamate that peaked in the first 10 min fraction after trauma. Hypothermic animals showed a similar increase after trauma, which was statistically significant until 20 min after injury. The level of glutamate was significantly higher in hypothermic animals from 20 to 70 min after injury, compared with normothermic animals. Aspartate also showed a marked increase following injury. The peak concentration was similar for both groups, whereas recovery was delayed in hypothermic animals. There was no significant difference between the normothermic and hypothermic animals for arginine, taurine, alanine, glutamine, histadine, glycine, threonine, tyrosine, and asparagine. No significant effect of hypothermia on lactate or lactate/pyruvate was noted. However, the mean level of lactate tended to be lower and recovery was quicker in hypothermic animals. The results of the present study suggest that moderate hypothermia does not attenuate extracellular accumulation of EAAs or markedly improve energy metabolism in our model. Instead, our findings raise the possibility that moderate hypothermia prolongs the duration of glutamate receptor overactivation. Since hypothermia effectively attenuates glutamate release in CNS and spinal cord ischemia models our results suggest different mechanisms of extracellular accumulation of EAAs in ischemia and trauma.

Acidosis, Lactic↗

Expression of the ubiquitin carboxyl-terminal hydrolase PGP 9.5 in axons following spinal cord compression trauma. An immunohistochemical study in the rat.

Protein gene product 9.5 (PGP 9.5) is a neuron-specific protein which acts as a ubiquitin carboxyl-terminal hydrolase. It facilitates the conversion of polyubiquitin to monoubiquitin, which can be reused for another catalytic cycle. Monoubiquitin plays an important role in degrading abnormal and denatured proteins. Previously, we have reported that ubiquitin-like immunoreactivity is expressed in axonal swellings following compression trauma to the rat thoracic cord. It was characterized by fast occurrence, progressive increase and gradual disappearance over a period of 9 days. The expression of PGP 9.5 has now been studied in the same material. Control rats showed a weak PGP 9.5 immunoreactivity in the nerve cell bodies of the cord. Except for the corticospinal tracts, the axons of other longitudinal tracts were weakly stained. Accumulation of PGP 9.5 immunoreactivity occurred in expanded axons at the site of compression already 4 h after trauma. They became more frequent in number 1 and 4 days after injury and remained so over the entire observation period of 9 days. The labelled axons were randomly distributed in the longitudinal tracts, but were never found in the corticospinal tracts. The extent of immunoreactivity was related to the degree of impact on the cord. Compression injury thus induces accumulation of both ubiquitin and PGP 9.5 immunoreactivity in axonal expansions. The injured axons may have a mechanism for degradation of proteins by the ubiquitin-mediated proteolytic pathway and another mechanism for effective ubiquitin regenerative cycling by the action of PGP 9.5.

Animals↗

Effects of alpha-phenyl-N-tert-butyl nitrone (PBN) on compression injury of rat spinal cord.

alpha-Phenyl-N-tert-butyl Nitrone (PBN) is a free radical scavenger which recently has proved to be neuroprotective in experimental studies on focal cerebral ischemia and infarction. We therefore studied the effect of this drug in a model of moderate compression injury to rat spinal cord at the midthoracic level. The compound was given intraperitoneally 0.5 h before (100 mg/kg b.w) and at 1.5 h (50 mg/kg b.w) and 3.5 h (50 mg/kg b.w) after compression. Treated animals and controls (vehicle alone) were allowed to survive for 1 or 9 days following trauma. The functional outcome was tested by the inclined plane method and the motor performance score. By using MAP2 immunostaining the number of nerve cell bodies in the ventral horn and the ratio of MAP2 immunostained area to area of whole section of the cord were assessed to detect loss of neurons and loss of dendrites in the compressed segment. beta APP and PGP9.5 immunostaining was used to demonstrate axonal lesions. Treated and control rats showed at day 1 when tested with the inclined plane method a marked reduction of the capacity angle. This abnormality recovered gradually over the following days and was normalized at day 9. The motor performance score showed a marked reduction at day 1 which almost normalized at day 9. There was no difference regarding the functional outcome between rats given PBN and controls in none one of these functional tests. The spinal cord of normal rats presented immunoreactivity to MAP2 in nerve cell bodies and dendrites but not in axons and other structures. Following compression there was at day 1 and 9 a marked loss of MAP2 immunoreactivity in dendrites and nerve cell bodies. We could not detect any difference between the PBN and the control rats regarding the degree of cell loss or degree of reduction of dendrite staining. No difference between the two groups was seen with the axonal immunostainings (beta APP and PGP9.5). In conclusion, our study did not reveal any neuroprotective effect of PBN on the functional outcome and morphology (immunostaining to MAP2, beta APP and PGP9.5) in this model of moderate compression trauma to rat spinal cord.

Amyloid beta-Protein Precursor↗

Changes in microtubule-associated protein 2 and amyloid precursor protein immunoreactivity following traumatic brain injury in rat: influence of MK-801 treatment.

We investigated by immunohistochemistry dendritic and axonal changes occurring in the rat brain after mild focal cortical trauma produced by the weight drop technique. One and 3 days after injury, nerve cell bodies and dendrites in the perimeter of the impact site displayed decreased microtubule-associated protein 2 (MAP2) immunoreactivity. Some dendrites in the immediate adjacent region were more intensely stained and distorted. The dentate hilar region of the hippocampus showed a reduction of immunoreactive nerve cell bodies and dendrites. Twenty-one days after injury the strongly stained cortical dendrites and the reduction of immunoreactivity in the hippocampus remained, whereas the reduced staining in the perimeter of the lesion had normalised. These results indicate that there is a long-lasting disturbed dendritic organisation implicating impaired neurotransmission after this type of mild brain trauma. beta-Amyloid precursor protein (APP) immunohistochemistry revealed numerous stained axons in the ipsilateral subcortical white matter and thalamus indicating local and remote axonal injuries with disturbed axonal transport. Twenty-one days after injury, numerous small immunostained profiles appeared in the neuropil of the cortical impact site and in the ipsilateral thalamus. The axonal changes indicate disturbed connectivity between the site of the impact and other brain regions, chiefly the thalamus. The presence of beta-amyloid was investigated 21 days after trauma. There were no signs of beta-amyloid depositions in the brain after injury. Finally, we tested if the non-competitive NMDA receptor antagonist dizocilpine maleate (MK-801) could influence the observed MAP2 and APP changes. Pretreatment with this compound did not affect the early MAP2 and APP alterations. Instead, an increased expression of the APP antigen in the thalamus was observed 21 days after trauma in the MK-801-treated animals. The cause of this phenomenon is not known but may be related to a delayed neurotoxic action of MK-801 treatment.

Amyloid beta-Protein Precursor↗

Muscle-nerve involvement in autosomal dominant progressive external ophthalmoplegia with hypogonadism.

Sixteen members of a family with a history of autosomal dominant progressive external ophthalmoplegia (adPEO) with hypogonadism were examined. The muscular involvement commenced cranially and descended in relation to increasing disease duration. The neuromuscular signs were PEO, dysarthria, dysphonia, limb muscle weakness with wasting, absence of Achilles tendon reflexes, and distal vibration sensory loss. The electromyogram (EMG) was myopathic in facial and proximal limb muscles. Neurogenic involvement was suspected in a few tibial anterior muscles. Neurography showed signs of axonal neuropathy correlated to clinical signs. F-responses were reduced in number or absent in peroneal nerves, and did not correlate to clinical signs or disease duration. Muscle biopsies in advanced cases had structural abnormalities of mitochondria, ragged-red fibers, and focal cytochrome c oxidase deficiency. A combination of muscle-nerve involvement with PEO, Achilles tendon areflexia, distal vibration sensory impairment, myopathic EMG, and abnormally low sural nerve responses seems to be typical of this type of mitochondrial disorder.

Adolescent↗

Increased expression of growth-associated protein 43 immunoreactivity in axons following compression trauma to rat spinal cord.

Growth-associated protein 43 (GAP43) is one compound used to indicate growth of axonal endings during development and regeneration, particularly of peripheral neurons. Using immunohistochemistry, we have studied the expression of GAP43 in the spinal cord of rats subjected to mild, moderate or severe compression injury and used neurofilament immunostaining to demonstrate axonal injuries. Samples removed from the compressed T8-9, the cranial T7 and the caudal T10 segments were studied at 4 h, 24 h, 4 days and 9 days after injury. Control rats showed a moderate immunostaining of neurons in dorsal root ganglia, weak staining of ventral motor neurons and, with the exception of the corticospinal tracts, a weak staining in some axons of the longitudinal tracts of the cord. Injury in the compressed region led to increased GAP43 immunoreactivity in axons of normal and expanded size. This occurred particularly 1-4 days after injury and normalized 9 days thereafter. More marked immunostaining was present in the cranial and caudal segments. The corticospinal tracts never showed such staining. The increase of GAP43 immunostaining is presumably caused by disturbed axonal transport from neurons with the capacity to synthesize and transport the GAP43 antigen. Transported material may thus be available for regeneration of axons, but this source of material may vary between different classes of axons within the cord.

Animals↗

Accumulation of beta-amyloid precursor protein and ubiquitin in axons after spinal cord trauma in humans: immunohistochemical observations on autopsy material.

We evaluated by immunohistochemistry the presence of beta-amyloid precursor protein (beta APP) and ubiquitin-like material which may accumulate in axons of the human spinal cord subjected to injury. Autopsy material was obtained from nine cases with different types of trauma: breech delivery with neonatal spinal injury, compression of the cord induced by fractures of the vertebral column, haematomas or intradural meningioma. The posttrauma period ranged from 10 days to several years. The spinal cord of six control cases without evidence of injury presented beta APP immunoreactivity in nerve cell bodies and in a few axonal profiles but not in dendrites. Seven of the nine cases with spinal cord trauma showed an accumulation of beta APP-immunoreactive material in axons of the longitudinal tracts at the site of the injury. Five cases presented similar axonal immunoreactivity in the grey matter of the cord. Ubiquitin-like immunoreactivity was present in expanded axons in cases with spinal cord injury. Cases with spinal cord trauma thus present beta APP-immunoreactive axons particularly of the longitudinal tracts in the same way as in trauma to rat spinal cord and in various brain injuries. The aggregation of beta APP-immunoreactive material indicates disturbed axonal transport of beta APP. Accumulation of ubiquitin-like immunoreactive material in expanded axons at the site of trauma may be one prerequisite for degradation of abnormal proteins by the ubiquitin-mediated proteolytic pathway.

Adolescent↗

Involvement of nitric oxide in acute spinal cord injury: an immunocytochemical study using light and electron microscopy in the rat.

The possibility that nitric oxide participates in the pathophysiology of spinal cord injury was examined using a constitutive isoform of neuronal nitric oxide synthase immunoreactivity in a rat model. Spinal cord trauma was produced by making an incision into the right dorsal horn of the T10-11 segments. Five h after trauma, a marked upregulation of NOS-immunostained neurons was seen in the perifocal T9 and T12 segments of the cord. The immunolabelling was most pronounced in the dorsal horn of the ipsilateral side. Topical application of an antiserum to nitric oxide synthase (NOS) 2 min after injury prevented the trauma-induced upregulation of NOS-immunoreactivity. In contrast, application of preabsorbed serum or L-NAME, an inhibitor to NOS, was ineffective in reducing the induction of NOS-immunoreactivity. Trauma caused a marked expansion of the cord and resulted in marked cell changes. This expansion and cell reaction was significantly reduced following application of NOS antiserum but it was not seen after application of preabsorbed antiserum or L-NAME. Our results for the first time show that a focal trauma to the spinal cord has the capacity to upregulate neuronal NOS immunoreactivity and that application of NOS antiserum has a neuro protective effect. This indicates that nitric oxide is somehow involved in the pathogenesis of secondary injuries after spinal cord trauma.

Amino Acid Sequence↗

Effects of methylprednisolone on extracellular lactic acidosis and amino acids after severe compression injury of rat spinal cord.

We evaluated in rats with severe spinal cord compression at T8-9 the influence of methylprednisolone (MP) on lactic acidosis and extracellular amino acids, which may cause secondary, perifocal injuries of the cord. MP (30 mg/kg) was given intravenously 30 min before compression and hourly thereafter (15 mg/kg). Other rats with compression, given saline, served as controls. Samples from the extracellular fluid of one dorsal hom were collected by microdialysis and analyzed by HPLC. Microdialysis was performed for 1.5 h to establish basal levels. Samples were collected for 3 h after compression. MP-treated rats showed a reduction of dialysate lactic acid and arginine levels during the first 1-2 h after trauma. The mean dialysate levels of glutamate in MP-treated rats were lower than those of the controls, but the difference was not statistically significant. MP treatment did not influence dialysate levels of aspartate, glutamine, histidine, glycine, threonine, taurine, alanine, GABA, and tyrosine. Our study shows that MP has several effects, including reduced lactic acid formation, reduced levels of arginine (the substrate for nitric oxide production), and a trend toward decreased extracellular accumulation of the excitotoxic amino acid glutamate. We conclude that MP has the capacity to change the composition of the extracellular edema fluid after trauma to the spinal cord. These changes may counteract free radical formation and may be important mechanisms by which MP exerts its beneficial actions.

Acidosis, Lactic↗

Changes of extracellular levels of amino acids after graded compression trauma to the spinal cord: an experimental study in the rat using microdialysis.

We evaluated in rats, the time course of changes in extracellular levels of amino acids, lactate and pyruvate, which ensued spinal cord compression of mild, moderate, and severe degrees. The neurochemical findings measured by HPLC were compared with known outcome measures of this model. A laminectomy of vertebrae Th7 and Th8 was made and a microdialysis probe was inserted in one dorsal horn. Fluid samples were collected at intervals of 10 min. Dialysate lactate and lactate/pyruvate ratios increased in proportion to the severity of injury, suggesting a progressive derangement of energy metabolism. Mild trauma, with no neurologic deficits, did not induce any remarkable change of amino acids, but taurine values were temporarily slightly elevated. Moderate trauma, leading to transient paraparesis, resulted in a transient rise of glutamate and taurine. Severe trauma resulting in paraplegia of the hind limbs induced profound changes of extracellular amino acids. Glutamate and aspartate rose 5-6 times above basal level. There were marked elevations of taurine, glycine, arginine, alanine, asparagine, histidine, serine, threonine, and tyrosine after this degree of trauma. Glutamate, aspartate, and taurine returned to the basal level within 50 min, whereas most of the other amino acids remained elevated throughout the experiment. Thus, we found profound disturbances of extracellular amino acids and energy metabolites. The elevations of glutamate and aspartate correlated with previously recorded data on neurological outcome. The composition of the early extracellular edema showed marked temporal changes related to the severity of impact. Future studies regarding treatment of traumatic edema should focus on its chemical composition as well as its volume since such edema is not uniform in composition.

Amino Acids↗

Apoptosis and expression of Bcl-2 after compression trauma to rat spinal cord.

We have evaluated by in situ nick-end labeling the presence of apoptotic cells in the spinal cord of rats with compression injury at the level of Th8-9 of mild, moderate, and severe degrees resulting in no neurologic deficit, reversible paraparesis, and paraplegia, respectively. Rats with compression injury surviving 4 or 9 days showed apoptotic glial cells in the longitudinal tracts of the Th8-9, the cranial Th7, and the caudal Th10 segments. The apoptotic cells were most frequently observed in Th7. They did not express glial fibrillar acidic protein (GFAP) and their morphology was compatible with that of oligodendrocytes. Neurons of the gray matter did not present signs of apoptosis. In addition, we studied the immunohistochemical expression of Bcl-2, an endogenous inhibitor of apoptosis. Compression induced Bcl-2 immunoreactivity in axons of the long tracts, particularly after moderate and severe compression and 1-day survival. Neurons of dorsal root ganglia were immunoreactive but the neurons of the spinal cord were unstained. The accumulation, presumably caused by arrested axonal transport in sensory pathways, was absent in rats surviving 9 days. In conclusion, compression trauma to rat spinal cord induces signs of apoptosis in glial cells, presumably oligodendrocytes of the long tracts. This may induce delayed myelin degeneration after trauma to the spinal cord. Bcl-2 does not seem to be upregulated in oligodendrocytes.

Animals↗

Fundamental pathological lesions in vascular dementia.

This review concerns the fundamental cerebral lesions in cases of vascular dementia. Extracerebral vascular alterations are dominated by atherosclerosis with or without thrombosis. In addition, occlusion of extracerebral arteries can be induced by thrombo-embolism and in rare cases by other vascular diseases, chiefly arteritis. Intracerebral microangiopathies are usually of arteriolosclerotic or hyalinotic types in which there is degeneration of smooth muscle cells of the media and deposition of components of extracellular matrix, chiefly collagens. Ageing, chronic hypertension, hyperlipidemias and diabetes are important factors inducing vascular lesions. The vascular lesions, often combined with systemic factors, may produce various ischemic and edematous alterations of the brain parenchyma. Occlusion and obliteration of arteries (macroangiopathy) are associated with large infarcts, whereas microangiopathy may cause lacunar infarcts and some forms of white matter degeneration. Cases of vascular dementia usually present many types of lesions in the brain parenchyma and its arterial supply. The extent and location of the injuries differ considerably from case to case. Location of the lesions, volume of destroyed tissue, multiplicity and bilateral occurrence are most important parameters underlying the clinical manifestations in vascular dementia. A strategic location of a small injury is in some cases of particular importance.

Aged↗