PubMed Health⌕ Search

Biomedical subjects

Key Chung Park

Publications and source records attributed to Key Chung Park.

8 recordsLinked to original sources
PubMed2006

Secondary mania in a patient with delayed anoxic encephalopathy after carbon monoxide intoxication.

Mania is a rare clinical manifestation of delayed anoxic encephalopathy (DAE). Prior case reports on mania after hypoxic injury involved patients with a previous history of mania or depression, potentially reflecting a recurrence of premorbid mood disorders after hypoxia rather than pure secondary mania. Herein, we report a 55-year-old woman with no past history of neurological or psychiatric illness, who developed mania as a symptom of DAE after carbon monoxide intoxication. Brain magnetic resonance imaging showed diffuse white matter lesions, particularly visible in the frontal white matter. This frontal lesion may have prevented frontal inhibition from being transmitted to the basotemporal limbic area, resulting in mania manifested as a burst of limbic activity.

Bipolar Disorder↗
PubMed2005

Micrographia on free writing versus copying tasks in idiopathic Parkinson's disease.

BACKGROUND: Only a few studies have reported on the frequency of micrographia in idiopathic Parkinson's disease (IPD), and the definition of micrographia in these studies was based simply on the visual inspection of the patients' free writing. OBJECTIVES: We investigated the frequency of consistent (CM) and progressive (PM) micrographia by quantifying the patients' copying of a target letter or figure. METHODS: Seventy-five IPD patients and 30 sex/age matched healthy controls were assigned the tasks of free writing and letter/figure copying. CM was defined by the average size of the letter or figure written or copied by the patients below the controls' mean-2SD. PM was defined by the slope of reduction in size as a function of the serial positioning of the letters/figures below the mean-2SD of the controls. RESULTS: In the free writing, of 75 patients, only one met the criteria for the definition of CM and two met the criteria for the definition of PM definition. In contrast, letter/figure copying tasks identified 33 (44%) patients with CM and 19 (25%) with PM. CONCLUSION: Our study suggests that the prior definition of CM or PM by visual inspection in free writing task is less valid, and that the definition of CM and PM, based on the letter/figure copying tasks rather than free writing tests, could be more objective.

Aged↗
PubMed2005

Left hemispatial visual neglect associated with a combined right occipital and splenial lesion: another disconnection syndrome.

Damage to the left occipital lobe and the splenium or forceps major is often associated with pure alexia, thought to be an occipital-temporoparietal disconnection syndrome. A patient with the parallel lesion, a combined right occipital and splenial lesion, showed severe left-sided visual spatial neglect, but no significant neglect in other sensory modalities. This visual neglect might be related to a disconnection between the visual information processed by the left occipital lobe and the right posterior temporal-inferior parietal areas that mediate attention in the left hemispace.

Aged↗
PubMed2004

Transglutaminase 2 induces nitric oxide synthesis in BV-2 microglia.

A hallmark of brain inflammation is the activation of microglia. Excessive production of nitric oxide (NO), as a consequence of increased inducible nitric oxide synthase (iNOS) in glia, contributes to neurodegeneration. Transglutaminase 2 (TGase 2) is a cross-linking enzyme, which is increased in neurodegeneration. TGase 2 is also considered to be a useful and reliable marker for activation levels in resident and inflammatory macrophages. Therefore, an increase of TGase 2 expression may contribute to activation of microglia. To test this hypothesis, we analyzed the expression of TGase 2 in BV-2 microglia activated with lipopolysaccharide (LPS). Total TGase activity was increased about 5-fold after 24h exposure to LPS. The increase of NO synthesis is correlated with increase of TGase 2 expression. Secretion of NO was reduced between 40 and 80% by TGase inhibition in a dose-dependent manner. This suggests that TGase 2 appears to control iNOS transcription.

Animals↗
PubMed2004

Mechanism of the closing-in phenomenon in a figure copying task in Alzheimer's disease patients.

The"closing-in phenomenon"in figure copying tasks refers to a tendency to copy near the target, or to overlap the target to be copied. The mechanisms underlying the closing-in phenomenon have not been fully elucidated. We posit that closing-in may be related to the patients'compensatory strategies to overcome visuospatial dysfunction or visuospatial working memory deficit. Thus, it is expected that as the complexity of the target figure or the distance from the target to the copying space is increased, the magnitude of closing-in will be increased. Thirteen patients with Alzheimer's disease (AD) who demonstrated closing-in on a screening test and 15 healthy controls participated in this study. Each subject copied figures in conditions that varied in terms of figure complexity and distance from the target to the copying space. Neither figure complexity nor distance between the target and copying space affected the degree of closing-in in normal subjects. In contrast, in AD patients, the magnitude of closing-in increased as a function of figure complexity; however closing-in was unchanged by varying the distance from the target to the copying space. Our results suggest that copying near the target figure might be the patients'strategy to compensate for their visuospatial dysfunction or visuospatial working memory deficits.

Aged↗
PubMed2004

Pseudoneglect in solid-line versus character-line bisection tasks: a test for attention dominance theory.

OBJECTIVE: Normal subjects tend to bisect lines slightly to the left of the true midpoint, a phenomenon termed pseudoneglect. To test whether pseudoneglect relates to the right hemisphere's dominance for spatial attention or to the hemispheric difference in processing global-local stimulus properties, we administered conventional solid-line (SBT) and novel character-line (CBT) bisection tasks to normal subjects of different ages. METHODS: Normal subjects, consisting of 40 young and 40 older individuals, received 3 experimental tasks, a standard SBT and 2 types of CBT. Each subject completed 10 consecutive trials of each task presented in counterbalanced order between subjects. RESULTS: Across age groups, deviations on CBT were further to the right than those of SBT, and the leftward bias (pseudoneglect) was significant only in SBT. CONCLUSION: These results indicate that the bisection errors in normal subjects depend on the characteristics demanded by the specific task. Thus, our findings argue against the attention dominance theory and support a "task specificity" theory for pseudoneglect.

Adult↗
PubMed2003

Microglial phagocytosis of dopamine neurons at early phases of apoptosis.

Transection of the medial forebrain bundle caused apoptosis of dopamine neurons in the rat substantia nigra. Immunohistochemical localization of activated microglia and tyrosine hydroxylase in the axotomized substantia nigra showed that activation of microglia was rapid and OX-6 (MHC-II marker)-positive and ED1 (lysosomal phagocytic marker)-positive microglia were apposed to structurally intact tyrosine hydroxylase-positive dopamine neurons, indicating microglial phagocytosis of degenerating dopamine neurons. The occurrence of microglial phagocytosis at early stages of apoptosis may indicate the evolution of apoptosis into an irreversible state. Alternatively, interventions that suppress early activation of microglia might lead to novel mechanisms for neuron protection.

Animals↗