Biomedical subjects

Dong Hoon Shin

Publications and source records attributed to Dong Hoon Shin.

At least 37 records · Page 2Linked to original sources

PubMed2004

Distribution of heat shock protein 108 mRNA during the development of the chicken brain.

The developmental expression of heat shock protein 108 (HSP108) mRNA was mapped in chicken brain using in situ hybridization and reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR showed that HSP108 mRNA increased from embryonic day 5 (E5) to 13 (E13), significantly decreased from E17 to E21 and then increased again at the adult stage. In situ hybridization showed that while intense HSP108 positive (HSP108+) signals were localized in the cerebellum from E7 to E14, the intensities of these signals were significantly decreased at E17. However, at the adult stage, HSP108 expression increased in a cell type dependent manner. A decrease in HSP108 mRNA expression during differentiation was also observed in an in vitro study of brain cells treated with nerve growth factor (NGF).

Age Factors↗

PubMed2004

Subcellular localization of WD40 repeat 1 protein in PC12 rat pheochromocytoma cells.

The dynamics of actin filament protein is crucial for various physiological processes of the cells. Among the proteins correlating with actin dynamics, a novel 67-kDa WD40 repeat protein 1 (WDR1) was the vertebrate homologue of actin-interacting protein 1 (Aip1). Even though previous studies have provided the clues on the function of WDR1 in specific organs under pathological conditions, the exact subcellular localization of WDR1 is not known. Therefore, in the present study, we undertook to determine the distribution of WDR1 within PC12 pheochromocytoma cells (PC12 cells) using light and electron microscopic techniques. Double immunocytochemistry clearly showed that WDR1 immunoreactivities (IRs) were co-localized with anti-actin antibody, suggesting the involvement of WDR1 in actin dynamics. WDR1 immunoreactivities (IRs) in PC12 cells showed different distribution patterns as nerve growth factor (NGF) concentrations varied. During active proliferation, the distribution of WDR1 IRs seemed to be similar to those found in cortical actin patches, whereas WDR1 IR was observed in cytoplasmic actin cables after PC12 cells were induced to differentiate by treating with NGF. Though further studies are necessary to determine the function of WDR1, the current data represents a first step towards the in vitro study of WDR1 protein.

Actins↗

PubMed2004

The distribution of c-myb immunoreactivities in the adult mouse retina.

The myb gene family is composed of three different myb-related genes, A-, B- and c-myb. Among these, the presence of c-myb mRNA in developing and adult retina was previously reported. However, further study on the expression of c-myb in the retina is warranted because the previous study was only performed on developing retinal tissues by in situ hybridization technique. Therefore, in this study, we tried to perform immunohistochemical study, with a focus on the c-myb protein expression in adult retina. Although the cell types were unconfirmed, c-myb protein was likely to have been found in the ganglion, amacrine, horizontal and photoreceptor cells, judging from their locations and morphologies. The experimental data suggested that c-myb immunoreactivities were expressed by the cells in the neural retina, even in the adult stage, especially within some types of cells in specified retinal layers. This suggests that c-myb might play a role in the physiology of the retinal cells, not only in differentiation during retinal development.

Animals↗

PubMed2004

Potent Inhibitory effect of flavonoids in Scutellaria baicalensis on amyloid beta protein-induced neurotoxicity.

The free radical scavenging activities of two major flavonoids (baicalein and baicalin) in Scutellaria baicalensis were determined. The antioxidant capacities of baicalein and baicalin were determined by the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(*)(-) scavenging assay and showed about 110 and 70% vitamin C equivalent antioxidant capacity, respectively. Because amyloid beta (Abeta) protein is known to increase free radical production and lipid peroxidation in PC12 nerve cells, leading to apoptosis and cell death, treatment with baicalein and baicalin may result in the prevention of cellular damage by the Abeta-induced reactive oxygen species. We found that baicalein and baicalin resulted in a dose-dependent anti-Abeta toxicity by means of three different assays [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction, lactate dehydrogenase release, and trypan blue exclusion assays]. These results suggest that baicalein as well as baicalin can reduce the cytotoxicity of Abeta protein in PC12 cells, possibly by a reduction of oxidative stress, and these flavonoids may be useful in the chemoprevention of Alzheimer's disease.

Amyloid beta-Peptides↗

PubMed2004

Antimicrobial susceptibility patterns and macrolide resistance genes of viridans group streptococci from blood cultures in Korea.

OBJECTIVES: Our aim was to study the antimicrobial susceptibilities and macrolide resistance mechanisms of viridans group streptococci (VGS) in a Korean tertiary hospital. METHODS: MICs of five antimicrobials were determined for 106 VGS isolated from blood cultures. The macrolide resistance mechanisms of erythromycin non-susceptible isolates were studied by the double-disc test and PCR. RESULTS: In all, 42.4% of the isolates were susceptible to penicillin. Nine of 61 penicillin non-susceptible isolates were fully resistant (MIC >/= 4 mg/L). Rates of non-susceptibility to erythromycin, clindamycin and ceftriaxone were 33.9%, 17.9% and 9.4%, respectively. Twenty-two (61.1%) of 36 erythromycin non-susceptible isolates expressed constitutive resistance to macrolide-lincosamide-streptogramin B antibiotics (a constitutive MLS(B) phenotype); 13 isolates (36.1%) expressed an M phenotype; and one isolate, a Streptococcus bovis isolate, had an inducible MLS(B) resistance phenotype. erm(B) was found in isolates with constitutive/inducible MLS(B) phenotypes, and mef(A) in isolates with the M phenotype. In three isolates (two isolates with a constitutive MLS(B) phenotype and in one isolate with the M phenotype), none of erm(A), erm(B), erm(C) or mef(A) was detected by PCR. CONCLUSIONS: Penicillin non-susceptible VGS were more resistant to erythromycin, clindamycin and ceftriaxone than were penicillin-susceptible isolates. A constitutive MLS(B) phenotype associated with erm(B) was the predominant mechanism of macrolide resistance among erythromycin non-susceptible isolates from this Korean hospital.

Anti-Bacterial Agents↗

PubMed2004

Postnatal development and age-related changes in the distribution of nitric oxide synthase-immunoreactive neurons in the visual system of rats.

We have determined postnatal development and age-related changes in the distribution of neuronal nitric oxide synthase (nNOS) in the visual system including superior colliculus (SC), dorsal nucleus of lateral geniculate body (dLGB) and visual cortex of rats. In SC, the number and intensity of immunoreactive cells were increased until postnatal day 21 (P21), and were comparably decreased during the following days. Both neurons and neuropil were intensely stained in dLGB at P21, and the staining intensity was decreased in aged rats. The number of nNOS-immunoreactive cells was increased from P7 to P28 and was decreased in aged rats. The first demonstration of different staining patterns in SC, dLGB and visual cortex during the postnatal days and aging suggests that NO may mediate both postnatal refinement and age-associated visual deficits in some brain regions.

Aging↗

PubMed2004

Induction of transcription factor c-myb expression in reactive astrocytes following intracerebroventricular kainic acid injection in mouse hippocampus.

The transcription factor c-myb is known to play an important role in the regulation of cellular proliferation and differentiation. Recently, the constitutive and aberrant expression of c-myb in the normal and Cu/Zn SOD mutant mouse brain was reported. However, the expression of c-myb in the process of reactive gliosis is not known yet. Here we report the delayed and protracted induction of c-myb in the brain of mice following kainic acid (KA) induced seizure. Our western blot analysis revealed that the amount of c-myb was dramatically increased in the brain 3 days after KA treatment. The induction of c-myb was sustained for more than 7 days after KA treatment. The c-myb immunoreactivity (IR) was restricted to neurons of the hippocampus in control mice. Three days after KA treatment, a strong c-myb IR was found in reactive astrocytes in the whole areas of the CA3 region. Thereafter, c-myb IR astrocytes were gradually concentrated around the CA3 region undergoing selective neuronal loss. A few c-myb IR astrocytes were continuously persisted in the CA3 region 14 days after KA treatment. These findings suggest a role of c-myb signal pathway in reactive gliosis in mice with KA induced seizure.

Animals↗

PubMed2004

Reactive astrocytes express PARP in the central nervous system of SOD(G93A) transgenic mice.

In the present study, we used the transgenic mice expressing a human Cu/Zn SOD mutation (SOD1(G93A)) as an in vivo model of amyotrophic lateral sclerosis (ALS) and performed immunohistochemical studies to investigate the changes of poly(ADP-ribose) polymerase (PARP) in the central nervous system. In the spinal cord of symptomatic transgenic mice, immunohistochemistry showed intensely stained PARP-immunoreactive glial cells with the appearance of astrocytes, which were confirmed as astrocytes by double-immunofluorescences. In the brainstem and cerebellum, PARP-immunoreactive astrocytes were observed in the medullary and pontine reticular formation, hypoglossal nucleus, vestibular nucleus, cochlear nucleus and cerebellar nuclei. On the contrary, no PARP-immunoreactive glial cells were observed in control mice although PARP-immunoreactive motor neurons were found. In presymptomatic transgenic mice, a few moderately stained neurons were observed, whereas PARP-immunoreactive astrocytes were not detected. The present study provides the first evidence that PARP-immunoreactive astrocytes were found in the central nervous system of symptomatic SOD1(G93A) transgenic mice, suggesting that reactive astrocytes may play an important role in the pathogenesis and progress of ALS.

Animals↗

PubMed2004

Protective effect of growth hormone on neuronal apoptosis after hypoxia-ischemia in the neonatal rat brain.

Recent studies have shown that growth hormone (GH) can reduce neuronal loss after hypoxic-ischemic injury (HI) in neonatal and juvenile rat brains. Here, we investigated whether GH exerts its neuroprotective role through an anti-apoptotic effect in neonatal rat brains damaged by severe HI. Gross and histological observations showed that the extent of brain damage was found to be reduced in GH-treated brain at E7 after injury. In a terminal transferase-mediated dUTP nick-end-labeling (TUNEL) study, TUNEL-positive apoptotic cells were localized only at the damaged region in animals treated with saline, which was confirmed by an electron microscopy. In an immunohistochemical study with anti-bcl-2, -bax, -bad, -neuronal nitric oxide synthase (nNOS), -inducible NOS (iNOS) and -endothelial NOS (eNOS) antibodies, we observed that bax, bad, iNOS and eNOS were elevated in the saline-treated group. This study thus suggests that the protective role of GH against HI injury is mediated thorough an anti-apoptotic effect, which offers the possibility of a GH application for the treatment of neonatal HI encephalopathy.

Animals↗

PubMed2003

Immunohistochemical study on the distribution of insulin-like growth factor I (IGF-I) receptor in the central nervous system of SOD1(G93A) mutant transgenic mice.

In the present study, we used the SOD1(G93A) mutant transgenic mice as an in vivo model of ALS and performed immunohistochemical studies to investigate the changes of insulin-like growth factor I (IGF-I) receptor in the central nervous system. IGF-I receptor-immunoreactive astrocytes were detected in the spinal cord, brainstem, central gray and cerebellar nuclei of SOD1(G93A) transgenic mice. In contrast to transgenic mice, no IGF-I receptor-immunoreactive astrocytes were observed in any brain region of wtSOD1 transgenic mice although a few moderately stained neurons were observed. In the hippocampal formation of SOD1(G93A) transgenic mice, IGF-I receptor immunoreactivity was increased in the pyramidal cells of the CA1-3 regions and granule cells of the dentate gyrus. The present study provides the first evidence that IGF-I receptor immunoreactivity was increased in reactive astrocytes in the central nervous system of SOD(G93A) transgenic mice, suggesting that reactive astrocytes may play an important role in the pathogenesis and progress of ALS. The mechanisms underlying the increased immunoreactivity for IGF-I receptor, and the functional implications of these increases, require elucidation.

Amyotrophic Lateral Sclerosis↗

PubMed2003

Histological analysis on the medieval mummy in Korea.

Recently, there have been some reports on the mummies from the medieval tombs in Korea, which were not made on purpose. Although these mummies could be an invaluable source for the studies on the physical state of medieval Koreans, there were not any reports on this subject until now. In this study, we first tried to investigate the various tissues using light- and electron-microscopic techniques. In the organs we have examined, even though the collagen fibers were profusely found within all of them, some types of cells, such as red blood cells, chondrocytes, hepatocyte and muscle cells, were also visible in various tissues. The histological characteristics of the current case seemed to be well matched with the previous study in general even though there were also somewhat different findings from the previous reports on the mummies. Although the cause of the mummification in Korea was not completely explained, we think that the cause in this case could be correlated with cultural aspects--not with natural conditions--because the mummies were only found in cases where the lime-soil barrier was maintained until their discovery, and which separated the inner space of the coffins from the outer space. As similar cases are frequently reported nowadays, invaluable data on the physical status of the medieval Koreans could be attainable if systemic investigation could be performed on similar cases which are found in the future.

Bayes Theorem↗

PubMed2003

Immunocytochemical study on the distribution of c-myb in the central nervous system of the transgenic mice expressing a human copper/zinc superoxide dismutase mutation.

Although our previous study showed the constitutive expression of c-myb in neurons, suggesting that this gene might be involved in the normal function of these cells, there were no reports on the expression pattern of c-myb under pathological conditions. In the present study, we first investigated the changes in c-myb immunoreactivities (IRs) in the central nervous system of the transgenic mice expressing a human copper/zinc superoxide dismutase (Cu/Zn SOD) mutation. The distribution of c-myb was enhanced in the various brain regions of transgenic mice expressing a mutated human Cu/Zn SOD gene. Immunohistochemistry showed intensely stained c-myb IR glial cells with the appearance of astrocytes within the various brain regions of transgenic mice such as the gray matter of the midbrain, medulla oblongata and spinal cord. Even though the exact functions of c-myb in the normal and pathological states were not clearly revealed until now, we think that the increase in c-myb expression in the mutant mice could be due to the compensate mechanism of the astrocytes for the reduced defence against superoxide toxicity because the only known function of c-myb was its correlation with the prevention of programmed cell death, which could be deduced from the previous studies.

Animals↗

PubMed2003

Vasoactive intestinal peptide (VIP) and VIP mRNA decrease in the cerebral cortex of nNOS knock-out(-/-) mice.

Although there is much evidence showing that NO regulates the release of VIP in several areas, there is no report about the influence of NO on VIP in the cerebral cortex. We therefore examined changes in VIP expression in the cerebral cortex of nNOS knock-out(-/-) mice using immunohistochemistry and in situ hybridization. The nNOS((-/-)) mice had significantly fewer VIP-immunoreactive neurons than the control mice and the VIP mRNA as well as the VIP-immunoreactivity of the individual neuron was decreased in the nNOS((-/-)) mice. The first demonstration of decrease in VIP expression in the cerebral cortex of nNOS((-/-)) mice may provide useful data for investigating the relation between NO and VIP in the cerebral cortex and the mechanisms of many functions of these two neurotransmitters.

Animals↗

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

Heat shock protein 108 mRNA expression during chicken retina development.

In a developmental study on the expression of heat shock protein 108 (HSP108) mRNA in the chicken retina, we found different spatial and temporal expressions of HSP108 mRNA in each retinal layer. While intense HSP108 signals were found in the retina neuroblast layer at embryonic day 5 (E5), the ganglion cell population (GC), inner nuclear layer (IN) and pigment epithelium (PE) showed HSP108 expression at E9. At E14, HSP108 signals were reduced versus the previous stages even though signals were still detected in the GC, the IN, the outer nuclear layer and the PE. HSP108 signals were still detectable at the E21 stage, although each retinal layer showed a much differentiated morphology and diminished signal intensity. These results suggest that HSP108 expression might be developmentally regulated throughout eye organogenesis and that it plays a role in ocular development.

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

Glial cells in the chicken optic tectum.

We mapped the distribution of the three neuroglial cells, oligodendrocytes, astrocytes and microglia, in the chicken optic tectum using their specific markers, transferrin binding protein (TfBP), glial fibrillary acidic protein (GFAP), and Ricinus communis agglutinin-1 (RCA-1), respectively. Neuroglial cells showed distinct distribution according to their cell types. While the astrocytes were mainly found in the stratum opticum (SO), stratum album centrale (SAC) and stratum fibrosum periventriculare (SFP), with their processes extending throughout the entire optic tectum region, the oligodendrocytes were mainly scattered in the SO, stratum griseum centrale (SGC) and SAC. In the case of the microglia, ramified cells were found in nearly all the layers, with the majority being present in the SAC. This is the first report demonstrating the distribution of glial cells in the chicken optic tectum, and these findings may present a basis for further study.

Animals↗