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S Kwak

Publications and source records attributed to S Kwak.

54 records · Page 3Linked to original sources
PubMed1991

Multicatalytic proteinase is present in Lewy bodies and neurofibrillary tangles in diffuse Lewy body disease brains.

A non-lysosomal multicatalytic proteinase (MCP) is immunohistochemically visualized in Lewy bodies and loosely arranged globose tangles but not in the majority of compact neurofibrillary tangles in brains with cortical diffuse Lewy body disease. Virtually all Lewy bodies are immunoreactive to MCP, exhibiting various staining patterns where they are moderately diffuse, intense in the central core or intense in the peripheral rim. MCP may be involved in the formation of these inclusions.

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PubMed1991

A case of adult onset pure pallidal degeneration. I. Clinical manifestations and neuropathological observations.

We present a case of adult onset progressive neurodegenerative disease with a selective involvement in the globus pallidus (GP). The main symptom was extreme slowness in motion without rigidity, which was distinct from akinesia of parkinsonism. Dystonic posture developed in neck and fingers and mild rigidospasticity appeared in a later stage. Neuropathological examination shows a selective neuronal loss with gliosis in GP and degeneration of the efferent fibers. Although the subthalamic nucleus is slightly atrophic with minimal gliosis, there is no neuronal loss in the nucleus. The rest of the structures are pathologically insignificant. Because the pathological change is confined to GP neurons and their efferent fibers, we think that the marked slowness in motion and dystonic posture are ascribable to the selective GP lesion. A degenerative neurological disorder preferentially involved in GP was reported as pure pallidal degeneration (PPD). The onset of the PPD was in the first or second decades and the main symptoms were choreoathetosis, torsion dystonia and progressive rigidity. These distinct clinical features seemed to distinguish the present case from the previously described PPD. Therefore, we would like to call our case "adult onset" PPD. Clinicopathological correlation is discussed.

Adult↗
PubMed1991

A case of adult onset pure pallidal degeneration. II. Analysis of neurotransmitter markers, with special reference to the termination of pallidothalamic tract in human brain.

We analyzed neurotransmitter markers in a brain of a very rare case of pathologically confirmed adult-onset pure pallidal degeneration (PPD) as compared with 16 controls. Neurotransmitter concentrations are significantly altered in the globus pallidus (GP), subthalamic nucleus (ST) and the thalamic nuclei. Concentrations of gamma-aminobutyric acid (GABA) in the external segment (GPe) and internal segment (GPi) of GP and ST are decreased to 62, 45 and 55% of the control mean, respectively. Concentrations of glutamic acid are increased in GPi (144%) and ST (134%). Choline acetyltransferase (ChAT) activities are increased in GPe (232%), GPi (218%), ST (161%), and ventroanterior (VA, 210%) and ventrolateral nucleus (VL, 193%) of the thalamus. Noradrenaline (NA) concentrations in GPe and GPi are 56 and 43% of the control mean, respectively. Dopaminergic and serotonergic systems show no remarkable change. The grid microdissection analysis demonstrates a patchy GABA distribution in the thalamus of 3 controls, whereas a small GABA-rich area in the ventro-oral nucleus (VO) according to the atlas of Hopf disappears in adult onset PPD. These results strongly suggest that (1) GP GABAergic neurons are selectively degenerated and striatopallidal GABAergic nerve terminals are hypoactive; (2) ChAT activities in GP, ST, VA and VL are increased; (3) the subthalamopallidal glutamatergic system is not hypoactive; (4) activity of the noradrenergic system in GP is decreased; and that (5) VO in the thalamus specifically receives GABAergic nerve terminals from GP in human brain.

Adult↗
PubMed1991

Systemic administration of acromelic acid induces selective neuron damage in the rat spinal cord.

A single systemic administration of acromelic acid A (ACRO), a novel kainate analogue (kainoid), induces a series of characteristic behavioral changes in association with selective damage of interneurons in the caudal spinal cord in adult rats. When ACRO (5 mg/kg) was systemically administered, rats displayed forced extension of hindlimbs followed by frequent cramps and generalized convulsion. Most rats died during the convulsions without neuropathological change. Two rats developed long-lasting spastic paraparesis which persisted at least 3 months. Neuropathological changes were observed only in the rats with persistent paraparesis, in which neuron damage was identified selectively in small interneurons in the lumbosacral cord. The regional difference between kainate- and ACRO-induced neuron damage suggests the existence of plural kinds of kainate receptor subtypes.

Animals↗
PubMed1990

[MRI pathology of the globus pallidus in a patient with oculogyric crisis and tremor].

A 24-year-old woman developed occasional attacks of oculogyric crisis at the age of 18. She also suffered from postural tremor, dystonic gait, pyramidal tract signs, and peripheral nerve damages. No history of encephalitis was elicited. Nerve conduction velocity revealed decreased velocity and amplitude. Needle electromyography showed a neurogenic pattern. Sural nerve biopsy showed marked Wallerian degenerations. Muscle biopsy revealed small grouped atrophies. It was unlikely that she suffered from juvenile Parkinsonism, and we failed to obtain an evidence of neuronal intranuclear inclusion disease. Recently, Furumoto et al. reported a similar case who developed oculogyric crisis at the age of 12. So far, some authors have reported about changes of MRI image in the putamen and the substantia nigra in extrapyramidal movement disorders. However, few have paid attention to the changes of the pallidum. The most characteristic finding in the present case was the restoration of signal intensity of the globus pallidus on T2 weighted high-field MRI. It is known that pallidal damages produce dystonic disorders. However, the exact role which the pallidum played in pathogenesis of our patient's signs and symptoms is unknown at now.

Adult↗
PubMed1989

Specific lesions of rat spinal interneurons induced by systemic administration of acromelic acid, a new potent kainate analogue.

A single systemic injection of acromelic acid, a potent kainate analogue, caused behavioral and pathological effects distinct from those seen after systemic kainate. There was an initial marked tonic extension of the rat hindlimb, followed often by convulsions and, in surviving rats, by a transient flaccid paralysis and, ultimately, a persistent spastic paraplegia. Pathological examination suggested specific lesions of interneurons in the lower spinal cord with little or no damage to the hippocampal neurons preferentially affected by systemic kainate.

Animals↗
PubMed1988

Denervation induces long-lasting changes in the distribution of microtubule proteins in hippocampal neurons.

The cellular distributions of tubulin and microtubule-associated protein 2 (MAP2) were examined in the dentate gyrus of the rat hippocampus after unilateral lesion of the entorhinal cortex, which destroys the major afferent pathway to dentate granule cells. Changes were observed in distribution of both tubulin and MAP2 in granule cell dendrites on the denervated side. After 24 h there was a noticeable increase in both anti-tubulin and anti-MAP2 staining in the outer two-thirds of the dentate molecular layer, corresponding to the area of denervation. This increased staining reached a maximum 1 week after the lesion. There was no change on the unlesioned side. During a subsequent second phase the region of increased anti-tubulin and anti-MAP2 staining became restricted, by 35 days after lesioning, to a narrow band mid-way through the molecular layer. This pattern remained the same until 6 months after the lesion, the longest time point examined. The results indicate that there is considerable plasticity in the microtubular cytoskeleton of dendrites in the adult brain and that rearrangements induced in it by axotomy can persist long after the immediate effects of denervation and subsequent re-innervation have subsided.

Animals↗
PubMed1988

Studies on neurotransmitter markers of the basal ganglia in Pick's disease, with special reference to dopamine reduction.

gamma-Aminobutyric acid (GABA), substance P and dopamine concentrations and choline acetyltransferase (ChAT) activity were measured in post-mortem cerebrocortical and basal ganglial areas of 14 controls and 4 patients with pathologically verified Pick's disease (1 classic case and 3 cases of the generalized form). GABA and substance P levels in the substantia nigra and the globus pallidus were generally decreased, corresponding to the moderate to severe loss of small neurones in the striatum. ChAT activities in the striatum varied from case to case, in proportion to various degrees of loss of large neurones in the striatum. These neurotransmitter abnormalities in Pick's disease were exactly the same as those in Huntington's disease. However, dopamine concentrations were markedly reduced in the striatum in Pick's disease, whereas striatal dopamine in Huntington's disease is reported to be increased. A dopamine reduction in the striatum of Pick's disease was more disproportionately prominent than expected for various degrees of nigral cell loss. This may be one of the important factors which prevents the generation of choreic movements in Pick's disease in spite of definite striatal atrophy similar to Huntington's disease.

Adult↗
PubMed1985

Studies on neurotransmitter markers and neuronal cell density in the cerebellar system in olivopontocerebellar atrophy and cortical cerebellar atrophy.

Glutamate, aspartate and gamma-aminobutyrate (GABA) concentrations and choline acetyltransferase (ChAT) activity were measured in postmortem cerebellar cortical areas and brainstem nuclei of 10 normal controls, 5 patients of olivopontocerebellar atrophy (OPCA) with multiple system atrophy (MSA) and 2 patients of cortical cerebellar atrophy (CCA). In addition, the neuronal cell density in the cerebellar cortex and the brainstem nuclei was determined, and the correlation between neurotransmitter markers and the neuronal cell densities were investigated. Glutamate and aspartate concentrations in the cerebellar cortical tissues were markedly varied from case to case of MSA (OPCA) and CCA patients. However, glutamate concentration in the anterior vermis showed a positive correlation coefficient with the density of granule cells (r = 0.554, 0.05 less than P less than 0.10) and, those in the posterior vermis and in the cerebellar hemisphere were positively correlated with cells in the inferior olive (r = 0.707 and 0.607, P less than 0.05, respectively). Aspartate concentration in the anterior vermis also has a positive correlation coefficient (r = 0.571, 0.05 less than P less than 0.10) with the density of cells in the inferior olive. GABA concentrations in the dentate nucleus were decreased in all cases of MSA (OPCA) and CCA, and were positively correlated with the degree of loss of Purkinje cells (r = 0.765, P less than 0.01). ChAT activities were decreased in certain cases of MSA (OPCA), but conversely, increased in CCA patients. ChAT activity in the posterior vermis has a positive correlation coefficient (r = 0.613, 0.05 less than P0.10) with the cell density in the pontine nucleus. A possibility of a compensatory increase of ChAT activity in CCA patients was discussed.

Adult↗
PubMed1984

Tridimensional distribution of markers of neurotransmitters within the "accumbens area" of normal human brains.

The distribution of glutamate decarboxylase and choline acetyltransferase in the accumbens area of five neurologically normal human brains was investigated. (1) For rostrocaudal distribution, frozen samples were taken by the punching method from several transverse sections (150 micron) of the accumbens area and the caudate-putamen were assayed. The glutamate decarboxylase activity was highest in the middle of the accumbens area. The choline acetyltransferase activity in the accumbens area was the same as that in the caudate-putamen at the rostral half and gradually decreased caudally, while the caudate-putaminal choline acetyltransferase remained unchanged throughout. (2) For a mapping of the distribution of both enzymes, a pair of transverse sections of the accumbens area was cut into 1 mm X 1 mm square blocks by the grid microdissection method. The glutamate decarboxylase activity was highest at the ventromedial part; the glutamate decarboxylase-rich area could be reconstructed as a confined ellipsoid zone deep in the accumbens area. The choline acetyltransferase activity was patchily distributed in the rostral half of the accumbens area. Although the demarcation of the human nucleus accumbens inferred from choline acetyltransferase and glutamate decarboxylase distribution is not precise, it is clear that the accumbens area which corresponds to the animal nucleus accumbens is separated from the remainder of the striatum.

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