Biomedical subjects

Bum Sun Kwon

Publications and source records attributed to Bum Sun Kwon.

8 recordsLinked to original sources

PubMed2005

Age-related changes in microvillar cells of rat olfactory epithelium.

The nature and function of microvillar cells (MVCs) of the mammalian olfactory epithelium (OE) are little understood. Previous studies have examined MVC morphology in the developing and mature OE, but not in the aged OE. The present study investigated the effect of aging on MVCs of the OE in male Sprague-Dawley rats using histological and immunohistochemical methods. OE of aged rats contained MVCs with marked hypertrophy and swollen end-feet, which reached the basement membrane. Such MVC features were not observed in the young OE. These MVC changes were more conspicuous in proximity to severely degenerated olfactory receptor neurons (ORNs) and supporting cells. The ratio of the number of MVCs to that of supporting cells increased with aging; however, MVCs in the aged OE were not proliferating cell nuclear antigen-immunoreactive. In addition, the total cell population was decreased in the aged OE. Thus, our results suggest that MVCs are non-neuronal and that they are more resistant to aging compared to ORNs and supporting cells.

Age Factors↗

PubMed2005

Glial fibrillary acidic protein is expressed in the aged rat olfactory epithelium.

CONCLUSION: Our findings suggest that the aging process induces changes in the phenotype of olfactory supporting cells in the rat. OBJECTIVE: To investigate age-related changes in the expression of astroglial intermediate filament proteins in the olfactory supporting cells of the rat. MATERIAL AND METHODS: The expression of nestin and glial fibrillary acidic protein (GFAP) in the olfactory epithelium (OE) of young (3 months) and aged (25 months) Sprague-Dawley rats was compared using Western blotting and immunohistochemistry. RESULTS: Western blot analysis showed nestin expression only in the young OE, whereas GFAP was detected only in the aged OE. Immunohistochemistry showed that GFAP was localized in the olfactory supporting cells of the aged OE, with regional differences.

Age Factors↗

PubMed2004

A new method to measure caudal motor conduction time using magnetic stimulation.

Although central motor conduction time (CMCT) has been used for the diagnosis of lumbosacral spinal stenosis (LSSS), its diagnostic value is limited due to the short length of the involved segment compared to the long length of the total conduction distance. To overcome this, we introduce a new method to measure the caudal motor conduction time (caudal MCT) using magnetic stimulation. Magnetic stimulation was applied to the vertex and the T12 and S1 spinous processes for transcortical, thoracic, and sacral stimulation, respectively, and compound muscle action potentials were recorded simultaneously from the rectus abdominis (RA) and the right and left abductor hallucis (AH) muscles using three channels. CMCT was calculated by the latency difference in the AH response between transcortical and sacral stimulation, and between transcortical and thoracic stimulation for RA. Caudal MCT was calculated by subtracting CMCT for RA from that for AH. Caudal MCT was delayed in patients with LSSS compared to normal persons. We suggest that measuring caudal MCT may be useful for the diagnosis of LSSS, but its diagnostic sensitivity and specificity requires prospective study.

Adult↗

PubMed2004

Widespread scleredema accompanied with a monoclonal gammopathy in a patient with advanced ankylosing spondylitis.

Scleredema is a rare cutaneous mucinosis characterized by chronic diffuse induration of the skin, and it is occasionally associated with a monoclonal gammopathy (MG). Ankylosing spondylitis (AS) is noted to be another, chronic systemic inflammatory disorder of the axial skeleton that may accompany the MG. However, patients with scleredema and AS accompanied with a MG have not been reported in the literature. We here report a 40-yr-old man with scleredema and advanced AS accompanied with a MG of IgA-kappa protein. Widespread, long-standing scleredema has been developed over 10 yrs after the initial manifestation of AS. It is uncertain whether the coexistence of scleredema and AS is more than coincidental.

Adult↗

PubMed2003

Growth-associated protein-43 is elevated in the injured rat sciatic nerve after low power laser irradiation.

Low power laser irradiation (LPLI) has been used in the treatment of peripheral nerve injury. In this study, we verified its therapeutic effect on neuronal regeneration by finding elevated immunoreactivities (IRs) of growth-associated protein-43 (GAP-43), which is up-regulated during neuronal regeneration. Twenty Sprague-Dawley rats received a standardized crush injury of the sciatic nerve, mimicking the clinical situations accompanying partial axonotmesis. The injured nerve received calculated LPLI therapy immediately after injury and for 4 consecutive days thereafter. The walking movements of the animals were scored using the sciatic functional index (SFI). In the laser treated rats, the SFI level was higher in the laser treated animals at 3-4 weeks while the SFIs of the laser treated and untreated rats reached normal levels at 5 weeks after surgery. In immunocytochemical study, although GAP-43 IRs increased both in the untreated control and the LPLI treated groups after injury, the number of GAP-43 IR nerve fibers was much more increased in the LPLI group than those in the control group. The elevated numbers of GAP-43 IR nerve fibers reached a peak 3 weeks after injury, and then declined in both the untreated control and the LPLI groups at 5 weeks, with no differences in the numbers of GAP-43 IR nerve fibers of the two groups at this stage. This immunocytochemical study using GAP-43 antibody study shows for the first time that LPLI has an effect on the early stages of the nerve recovery process following sciatic nerve injury.

Animals↗

PubMed2003

The correspondence between the labeling patterns of antibody RT97, neurofilaments, microtubule associated protein 1B and tau varies with cell types and development stages of chicken retina.

The correspondence between the labeling patterns of antibody RT97, neurofilaments (NF-M and NF-H), microtubule associated protein 1B (MAP1B) and tau, were studied in the developing chicken. At embryonic day 3 (E3), intense RT97 immunoreactivity (IR) was found to be localized in cells in the region adjacent to the intraretinal space, which separates the inner and outer layers of the optic cup, and this was sustained at E8. However, this pattern changed dramatically at E12, as the intensities of RT97 IR increased in the inner retinal layer, while the outermost layers showed only weak IR. The adult stage retina showed RT97 IR within the nerve fibers of the ganglion cells, the processes of the amacrine cells and the photoreceptors. Additional immunostainings for NF-M, -H, MAP1B and tau showed that the observed changes in RT97 IRs were due to the different expressions of these proteins at different development stages.

Animals↗

PubMed2003

Caveolin-3 expression during early chicken development.

Caveolin-3, a protein that is correlated with caveolae, is found in muscle cells, especially during their differentiation. Although the distribution of caveolin-3 has been studied in cases such as adult and late embryonic mammalians, the expression of caveolin-3 has not been clearly defined during chicken development. In this study, we detected intense caveolin-3 immunoreactivity (IR) as early as embryonic day 4 (E4), most of the signals were localized within the neural tube and myotome. While IRs in the brain occurred in radial glia at E6, these intensities were reduced to an almost undetectable level at E8. In the case of muscle cells, the exclusive localization of caveolin-3 in the cytoplasmic membrane was detected even at E11, much earlier than in mammalian muscle tissues. Although the caveolin-3 IR pattern was similar to that reported by previous studies, we found some interesting mismatches in the case of avian tissues. Although we are unable to explain caveolin-3 expression patterns in the early embryonic stages, this study could provide a basis for further study on the function of caveolin-3 in avian embryogenesis.

Animals↗

PubMed2003

Ultramicroscopical immunolocalization of PAX6 in the adult chicken retina.

Cell type-specific PAX6 protein expression was examined in all retinal layers of the normal chicken retina. The most intense PAX6 immunostaining was found in the ganglion cell and inner nuclear layers, and in lower amounts in the optic nerve fiber, the inner plexiform and the photoreceptor layers. PAX6 immunostaining was variable in terms of its subcellular localization, even within one cell. PAX6 immunostaining was mainly localized in nuclear heterochromatin of the ganglion cell and inner nuclear layers whereas in the outer nuclear layer, PAX6 immunostaining was only observed in the intercellular space and the cytoplasm. In photoreceptors, the myoid portion of the inner segment showed PAX6 immunostaining, but the ellipsoid portion and the outer segment did not. The ultrastructural distribution pattern of PAX6 in the adult chicken retina suggests that normal expression of PAX6 is variable even in subcellular structures in the same cell type.

Animals↗