Biomedical subjects

Jong-Hyun Kim

Publications and source records attributed to Jong-Hyun Kim.

At least 19 recordsLinked to original sources

PubMed2006

Depletion of ATP and release of presynaptic inhibition in the CA1 region of hippocampal slices during hypoglycemic hypoxia.

Transient recovery (TR) of evoked synaptic potentials and ATP depletion during the late stage of hypoxic hypoglycemic insults were investigated in rat hippocampal slices. TR was observed not only in the late stage of insult, but also during recovery. The concentration of ATP corresponded to the appearance (27% of control) and disappearance (15% of control) of TR. Paired pulse studies showed the presynaptic nature of the release of inhibition of synaptic transmission during TR. Both N- and P/Q-type voltage-dependent calcium channels were involved in the appearance of TR. This evidence suggests that underlying mechanisms of TR appearance during hypoxic hypoglycemic insult might be related to ATP depletion and release of A1 adenosine receptor mediated inhibition of presynaptic voltage-dependent calcium channels.

Adenosine Triphosphate↗

PubMed2006

Internal carotid artery dorsal wall aneurysm with configurational change: Are they all false aneurysms?

BACKGROUND: Aneurysms arising from nonbranching sites of the ICA, so-called dorsal wall aneurysm, are rare entity, and present as blister type or saccular type. Occasionally configurational changes have been observed on serial cerebral angiography: a small blister-like bulge on ICA wall on initial angiography progressing to a saccular appearance within a few weeks. Such aneurysm showing configurational change has been regarded as a false aneurysm with fragile wall just like blister-type aneurysm, and direct surgical approach has been considered highly risky. CASE DESCRIPTION: A 42-year-old woman with a subarachnoid hemorrhage revealed small "blister-like" aneurysm at the medial wall of the ICA on initial angiography. After 12 days, the following angiograms demonstrated increased aneurysmal size and change of shape into a saccular configuration. Direct surgical approach was performed. The aneurysm had a relatively firm neck, and was successfully clipped without intraoperative rupture. The dome of aneurysm was resected after clipping and the histologic examination revealed it as a true aneurysm. CONCLUSIONS: This case suggests that all dorsal wall aneurysms with configurational change are not false aneurysms, and that angiographic findings do not always correlate with the nature of the aneurysmal wall; therefore, we should give more credence to direct surgical observation rather than preoperative angiographic findings when considering the most suitable surgical option.

Adult↗

PubMed2006

Comparison of alpha-synuclein immunoreactivity and protein levels in ischemic hippocampal CA1 region between adult and aged gerbils and correlation with Cu,Zn-superoxide dismutase.

In this study, we examined changes in the level and immunoreactivity of alpha-synuclein in the hippocampal CA1 region of adult (6 months old) and aged (24 months old) gerbils after 5 min of transient forebrain ischemia. The delayed neuronal death of CA1 pyramidal cells in adult gerbils was severer than that in aged gerbils 4 days after ischemia/reperfusion. Alpha-synuclein immunoreactivity in the CA1 region of adult and aged gerbils significantly changed after ischemia. In control animals, alpha-synuclein immunoreactivity and level in the aged-gerbil CA1 region were higher than those in the adult-gerbil CA1 region. In both adult and aged gerbils, alpha-synuclein immunoreactivity and level started to increase 3h after ischemia, and they were highest 1 day after ischemia. Thereafter, alpha-synuclein immunoreactivity and level decreased with time after ischemia. We also observed the effects of Cu,Zn-superoxide dismutase (SOD1) on ischemic damage using the Pep-1 transduction domain. Alpha-synuclein level in the CA1 region was lower in Pep-1-SOD1-treated adult and aged gerbils than in vehicle-treated adult and aged gerbils. We conclude that neuronal loss in the hippocampal CA1 region of adult gerbils was more prominent than that in aged gerbils 4 days after ischemia/reperfusion. The higher level of alpha-synuclein in the aged-gerbil CA1 region than that in the adult-gerbil CA1 region may be associated with the earlier induction of reactive oxygen species, and Pep-1-SOD1 potentially and reversibly inhibits the accumulation of alpha-synuclein in the CA1 region after transient ischemia.

Aging↗

PubMed2006

DPCPX-resistant hypoxic synaptic depression in the CA1 region of hippocampal slices: possible role of intracellular accumulation of monocarboxylates.

Adenosine plays the principal role in synaptic depression during various energy-depleted conditions. However, additional inhibitory factors not associated with A1 adenosine receptors appear to be involved in hypoxic insults. Monocarboxylate accumulation and consequent acidic changes during hypoxia may be responsible for this remaining depression in synaptic activity. Field evoked potentials were recorded in the CA1 region of rat hippocampal slices. Preincubation with 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) disclosed 43% of DPCPX-resistant synaptic depression (DRSD) during oxygen deprivation (OD). In contrast, no DRSD was detected in various conditions with limited glucose utilization, such as glucose deprivation and oxygen-glucose deprivation. Inhibition of anaerobic glycolysis (iodoacetate, sodium fluoride) abolished DRSD during OD, whereas blockade of monocarboxylate utilization with alpha-cyano-4-hydroxycinnamic acid (4-CIN) provoked DRSD in normoxic medium. These observations suggest that an intracellular accumulation of monocarboxylates is responsible for DRSD during hypoxia.

Action Potentials↗

PubMed2006

Comparative study on Cu,Zn-SOD immunoreactivity and protein levels in the adult and aged hippocampal CA1 region after ischemia-reperfusion.

In the present study, we investigated chronological changes in Cu,Zn-superoxide dismutase (SOD1) immunoreactivity and its protein levels in the hippocampal CA1 region of adult and aged gerbils after transient forebrain ischemia to compare ischemia-related changes in SOD1 in adult and aged gerbils. Delayed neuronal death in the CA1 region at 4 days after ischemic insult was prominent in adult gerbils compared to that in aged gerbils. In sham-operated gerbils, SOD1 immunoreactivity and protein level in the aged group were significantly higher than that in the adult group. At 12 h after ischemia-reperfusion, SOD1 immunoreactivity and protein level were increased in both the groups. At 1 day after ischemia, SOD1 immunoreactivity and protein level in the adult group were significantly increased: the SOD1 immunoreactivity was increased in non-pyramidal cells as well as pyramidal cells. At this time after ischemia, SOD1 immunoreactivity and protein level in the aged group were decreased: the immunoreactivity was decreased significantly in pyramidal cells. At 4 days after ischemia, SOD1 immunoreactivity was detected only in non-pyramidal cells of the CA1 region in both the groups. These results suggest that SOD1 in the gerbil hippocampal CA1 region is higher in sham-aged group than that in sham adult one, and that different changes in SOD1 in CA1 pyramidal cells after ischemia in adult and aged gerbils may indicate different processes in delayed neuronal death with time after ischemic insult.

Aging↗

PubMed2006

Alteration of the influences of HLA classes I and II alleles on the perinatal hepatitis B virus infection after immunoprophylaxis in Korean children.

Some HLA alleles are known to be associated with hepatitis B virus (HBV) persistence. In order to find out the relationship between HLA and perinatal HBV infection after prophylaxis, we typed HLA classes I and II in 38 HBeAg-positive mothers, their children (19 succeeded and 19 failed in prophylaxis) and 198 HBsAg-negative healthy controls. HLA-B35 (RR=2.8, p<0.03), Cw*07 (RR=2.7, p<0.02), DRB1*07 (RR=3.6, p<0.006), DQA1*02 (RR=3.6, p<0.02) and DQB1*02 (RR=2.4, p<0.05) alleles were higher and DRB1*13 (RR=0.3, p<0.03) and DPB1*0401 (RR=0.1, p<0.01) alleles were lower frequencies in HBeAg-positive mothers than in the control. In failed children to the perinatal HBV prophylaxis, HLA-Cw*0303 allele was significantly higher (p<0.05) and DPB1*0202 allele was lower (p<0.03) than in succeeded children. These results suggest the influences of certain HLA alleles on naturally acquired chronic HBV infection may be changed by perinatal HBV prophylaxis.

Journal Article↗

PubMed2006

Giant neurocysticercosis cyst in the cerebellar hemisphere.

A 67-year-old man presented with dizziness, nausea, and ataxia. Magnetic resonance imaging showed a large (5.5 x 4 x 4 cm) cystic lesion in the left cerebellar hemisphere with internal septation, a mural nodule, and thin rim enhancement. Cystic cerebellar tumor such as hemangioblastoma was initially suspected. Following surgery, the cyst was identified as cerebellar neurocysticercosis. Neurocysticercosis is the most common parasitic disease of the central nervous system but is occasionally misdiagnosed as tumor because of the varying neuroimaging presentation. This case shows that neurocysticercosis should be considered in the differential diagnosis of giant cystic lesions in the cerebellum as surgical intervention may be unnecessary.

Aged↗

PubMed2006

Combination treatment with temozolomide and thalidomide inhibits tumor growth and angiogenesis in an orthotopic glioma model.

The chemotherapeutic agent temozolomide (TMZ) and the anti-angiogenic agent thalidomide (THD) have both demonstrated anti-tumor activity in patients with recurrent malignant glioma. Combination treatment with TMZ and THD in patients with glioblastoma multiforme (GBM) appears to be more effective than treatment with either drug alone. To investigate the mechanism of this anti-tumor effect, we examined the combined effects of TMZ and THD in a rat glioma xenograft model. We found that combination treatment markedly inhibited the growth of tumors that were orthotopically implanted into rat brains. Using proliferating cell nuclear antigen (PCNA) staining, we observed a significant decrease in cell proliferation in these tumors. CD31 staining of the microvasculature revealed a significant decrease in angiogenesis. We also found increased apoptosis in treated tumors by terminal deoxynucleotidyl-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay. We further demonstrated that the expression of angiogenic factors, such as vascular endothelial cell growth factor (VEGF) and basic fibroblastic growth factor (bFGF), were inhibited by THD. THD also decreased the number of ED1-positive, activated macrophages or microglial cells, which produce pro-angiogenic molecules around the glioma. Taken together, these results suggest that combination treatment with TMZ and THD inhibits tumor growth via the induction of apoptosis and the inhibition of angiogenesis in a rat model and may be a promising therapy for malignant gliomas.

Angiogenesis Inhibitors↗

PubMed2006

Synergistic effect and condition of pegylated interferon alpha with paclitaxel on glioblastoma.

Glioblastomas are highly vascularized tumors and anti-angiogenic strategy is one of the most promising therapeutic approaches to treat brain tumors. Interferon alpha (IFN-alpha) as a single agent or combined with standard chemo-therapy has been shown to inhibit various tumors, but the effect of combination anti-angiogenic therapy on brain tumors has not been well studied. We determined the optimal dose and schedule of pegylated IFN-alpha (PEG-IFN-alpha) against U-87MG human glioblastoma cells growing orthotopically in nude mice, since several clinical trials reported that PEG-IFN-alpha administered at higher or lower doses was less effective. The group treated two times per week with injections of 10 KU of PEG-IFN-alpha for 4 weeks showed significant decreases in cell proliferation and angiogenesis. Moreover, the optimal dose and schedule of PEG-IFN-alpha determined in this study and combined with paclitaxel treatment potently inhibited tumor growth in vivo. The mechanisms of the significant therapeutic effects were most likely caused by directly inhibiting cell proliferation and angiogenesis, and rendering apoptosis increased. Specifically PEG-IFN-alpha/paclitaxel combination induced apoptosis of tumor-associated endothelial cells more than that of tumor cells. These results suggest that optimal biological dosage and scheduling of PEG-IFN-alpha and paclitaxel combination is a potent strategy for glioblastoma patients as a new synergistic anti-endothelial treatment.

Animals↗

PubMed2006

Surveillance of bacterial pathogens associated with acute diarrheal disease in the Republic of Korea during one year, 2003.

An epidemiological survey of human enterobacterial infections was conducted to determine the prevalence of enteropathogens in the Republic of Korea during one year, 2003. We tested for infectious diseases in 26,992 stool samples obtained from people who visited clinics located in six big cities and six rural provinces. From these samples, we isolated 1,291 cases of enteritis bacterial infection (4.8%). In the urban areas, 821 cases of bacterial infection (6.4%) were identified and, in the rural areas, 479 bacterial strains (3.3%) were isolated. Seasonal patterns were seen for diarrhea associated with S. aureus, E. coli and V. parahaemolyticus, while Salmonella and Shigella infections showed slight seasonal variation. We found that S. aureus and Salmonella were more frequently isolated from children and the elderly; however, the prevalence of E. coli, V. parahaemolyticus, and Shigella were similar in different age groups. Routine monitoring of these infections is considered a worthwhile means by which to elucidate their epidemiology and modes of transmission and ultimately to control them more effectively. Continuous laboratory-based surveillance for findings of enteritis bacterial infection should be emphasized in the prevention of these infections.

Acute Disease↗

PubMed2005

Exercise increased BDNF and trkB in the contralateral hemisphere of the ischemic rat brain.

Previous studies have suggested that brain-derived neurotrophic factor (BDNF) and trkB both have a role in plasticity following brain insults and exercise increases BDNF and trkB mRNA levels in the normal brain. We attempted to determine whether treadmill exercise improves motor function following experimental cerebral ischemia, and whether motor outcome is associated with BDNF and trkB expression. We subjected adult male Sprague-Dawley rats to a permanent ischemia, followed by either 12 days of treadmill exercise or non-exercise. In the exercise group, improvements in the motor behavior index were found and BDNF and trkB proteins in contralateral hemisphere were increased. This study suggests that after permanent brain ischemia, exercise improves motor performance and elevates BDNF and trkB proteins in the contralateral hemisphere.

Animals↗

PubMed2005

Susceptibility of cholangiocarcinoma cells to parthenolide-induced apoptosis.

Cholangiocarcinomas are intrahepatic bile duct carcinomas that are known to have a poor prognosis. Sesquiterpene lactone parthenolide, which is the principal active component in medicinal plants, has been used to treat tumors. Parthenolide effectively induced apoptosis in all four cholangiocarcinoma cell lines in a dose-dependent manner. However, the sarcomatous SCK cells were more sensitive to parthenolide than the other adenomatous cholangiocarcinoma cells. Therefore, this study investigated whether or not the expression of p53, the Fas/Fas ligand (FasL), Bcl-2/Bcl-X(L) determines the enhanced drug susceptibility of SCK cells. The results showed that Bcl-2 family molecules, such as Bid, Bak, and Bax, are involved in the parthenolide-induced apoptosis and that the defective expression of Bcl-X(L) might contribute to the higher parthenolide sensitivity in the SCK cells than in the other adenomatous cholangiocarcinoma cells. SCK cells, which stably express Bcl-X(L), were resistant to parthenolide, whereas Bcl-X(L)-positive Choi-CK cells transfected with the antisense Bcl-X(L) showed a higher parthenolide sensitivity than the vector control cells. Molecular dissection revealed that Bcl-X(L) inhibited the translocation of Bax to the mitochondria, decreased the generation of intracellular reactive oxygen species, reduced the mitochondrial transmembrane potential (deltapsi(m)), decreased the release of cytochrome c, decreased the cleavage of poly(ADP-ribose) polymerase, and eventually inhibited apoptotic cell death. These results suggest that parthenolide effectively induces oxidative stress-mediated apoptosis, and that the susceptibility to parthenolide in cholangiocarcinoma cells might be modulated by Bcl-X(L) expression in association with Bax translocation to the mitochondria.

Animals↗

PubMed2005

Identification of the genes involved in enhanced fenretinide-induced apoptosis by parthenolide in human hepatoma cells.

Fenretinide (N-4-hydroxyphenyl retinamide, 4HPR) is a synthetic anticancer retinoid that is a well-known apoptosis-inducing agent. Recently, we observed that the apoptosis induced by fenretinide could be effectively enhanced in hepatoma cells by a concomitant treatment with parthenolide, which is a known inhibitor of nuclear factor-kappaB (NF-kappaB). Furthermore, treatment with fenretinide triggered the activation of NF-kappaB during apoptosis, which could be substantially inhibited by parthenolide, suggesting that NF-kappaB activation during fenretinide-induced apoptosis has an antiapoptotic effect. This study investigated the molecular mechanism of this apoptotic potentiation by NF-kappaB inhibition. The genes involved in the enhanced fenretinide-induced apoptosis by parthenolide were identified using the differential display-PCR method and subsequent Northern blot or semiquantitative reverse transcriptase PCR analysis. This study identified 35 apoptosis-related genes including 12 unknown genes that were either up- or down-regulated by parthenolide. Interestingly, one up-regulated gene (HA1A2) was isolated and cloned from the liver cDNA, and was found to be identical to ANKRD1, which is also referred to as the CARP gene. Compared with controls treated with an empty vector or with antisense cDNA, the ectopic expression of ANKRD1 led to reduced colony formation and to enhanced apoptotic cell death in hepatoma cells. These results suggest that ANKRD1 and the other genes, whose expressions were substantially modulated by the parthenolide-mediated inhibition of NF-kappaB activation, play roles in the enhanced drug-induced apoptosis. In addition, this study suggests that those identified genes may be useful in anticancer strategies against hepatoma.

Amino Acid Sequence↗

PubMed2005

A retrospective analysis of 19,157 burns patients: 18-year experience from Hallym Burn Center in Seoul, Korea.

This is a retrospective, epidemiological study of 19,157 acute burn patients admitted to the Hallym Burn Centre, Hangang Sacred Heart Hospital, Seoul, Korea, during the period 1986-2003. The study was conducted to identify characteristics of burn patients that could lead to development of preventive programs to reduce both the frequency and mortality of burn injury. The majority of patients admitted had relatively minor burns, which were treated conservatively. Males predominated in all age groups with a summer peak seasonal variation. Typical burn in the children <5 years of age was a scald injury, occurring at home, affecting upper limbs and resulting in a relatively short hospital stay. Electrical burns due to steel chopsticks and steam burns due to electric rice cookers were also found in this age group. Adult burns, affecting upper and lower limbs, were caused by flames, hot liquids or electricity. Burns were sustained at the workplace and outdoors. Flame accidents in males were the leading cause of death with overall mortality of 8.2%. 13.9% of admissions needed intensive care and average length of hospital stay was 32.6 days. The annual number of patients undergoing burn related surgery has continuously increased reflecting a more aggressive surgical management. Our ongoing efforts are to promote prevention program and look for changes in the incidence of burn injury based on these epidemiologic features. Further study for implications of changes in management protocols and policies on treatment outcomes would improve the provision of appropriate care for the patients.

Accidents, Home↗

PubMed2005

Anatomic localization of motor points in gastrocnemius and soleus muscles.

OBJECTIVE: To identify the range of the terminal motor points of the triceps surae muscles in relation to bony landmarks. DESIGN: Eight limbs of four male cadavers were anatomically dissected. The range of terminal motor points from the tibial nerve to each triceps surae muscle was identified related to the bony landmarks. Bony landmarks were medial and lateral epicondyles of the femur and medial and lateral malleoli of the tibia. The length of the lower leg was defined as the distance from the intercondylar line of the femur to the intermalleolar line of the tibia. The locations of the motor points were expressed as the percentage of the length of the lower leg. RESULTS: The motor points of the medial gastrocnemius, lateral gastrocnemius, and soleus muscles were diffusely distributed along the muscle longitudinal bulk. The highest motor points of the medial gastrocnemius, lateral gastrocnemius, and soleus were located in 9.6% +/- 3.5%, 12.0% +/- 3.4%, and 20.5% +/- 3.9%, respectively, of the length of the lower leg. The lowest motor points were located in 37.5% +/- 5.5%, 37.9% +/- 2.3%, and 46.7% +/- 3.6%, respectively, of the length of the lower leg. CONCLUSIONS: The present study defined the longitudinal distribution pattern of terminal motor points in the triceps surae muscles. This concept can be helpful for further studies evaluating the effectiveness of the botulinum toxin injection method.

Cadaver↗

PubMed2005

Seroepidemiology of spotted fever group and typhus group rickettsioses in humans, South Korea.

The prevalence of spotted fever group (SFG) and typhus group (TG) rickettsioses was investigated in 3,362 sera by immunofluorescence assay. The serum samples were obtained from patients with acute febrile episodes in South Korea from December 1992 to November 1993. The number of polyvalent positive sera against SFG rickettsial agents at the level of 1: 40 dilution was 269 (8%) in Rickettsia sibirica, 482 (14.34%) in R. conorii, and 546 (16.24%) in R. akari. Many of the positive sera contained immunoglobulin (Ig) M antibodies rather than IgG antibodies. These results strongly suggest that SFG rickettsioses are prevalent in Korea. For TG rickettsial agents, the number of positive sera was 1,096 (32.60%) in R. typhi and 951 (28.29%) in R. prowazekii. Only a few epidemic typhus positive sera contained IgM antibodies. The result suggests that recent and/or primary infections of epidemic typhus were very rare in Korea during the said period. Among seven patients who had high titers (1:5,120) of IgG antibody to R. prowazekii, six were over 50 years old. The result suggests that Brill-Zinsser disease was prevalent in Korea.

Adolescent↗

PubMed2005

Role of the Nfa1 protein in pathogenic Naegleria fowleri cocultured with CHO target cells.

Naegleria fowleri, a free-living amoeba, exists as a virulent pathogen which causes fatal primary amoebic meningoencephalitis in experimental animals and humans. Using infected and immune mouse sera, we previously cloned an nfa1 gene from a cDNA library of N. fowleri by immunoscreening. The nfa1 gene (360 bp) produced a recombinant 13.1-kDa protein, and the Nfa1 protein showed pseudopodium-specific immunolocalization on a trophozoite of N. fowleri. In this study, the role of the Nfa1 protein as a cell contact mechanism of N. fowleri cocultured with target cells was observed by an immunofluorescence assay with an anti-Nfa1 polyclonal antibody. Using confocal microscopic findings, the Nfa1 protein was located on the pseudopodia of N. fowleri trophozoites. The Nfa1 protein in N. fowleri trophozoites cocultured with CHO target cells was also located on pseudopodia, as well as in a food cup formed as a phagocytic structure in close contact with target cells. The amount of nfa1 mRNA of N. fowleri was strongly increased 6 h after coculture.

Animals↗

PubMed2005

Gamma knife surgery for brain metastases in patients harboring four or more lesions: survival and prognostic factors.

OBJECT: This study was performed to evaluate the role of gamma knife surgery (GKS) in patients with a large number (four or more) of metastatic brain lesions. METHODS: The authors retrospectively reviewed the outcome in 130 patients who underwent GKS for metastatic lesions. Eighty-four patients presented with one to three lesions (Group A) and 46 presented with four or more lesions (Group B). The overall median survival time after GKS was 35 weeks. The median survival time in Group A (48 weeks) was significantly longer (p = 0.005) than the survival time in Group B (26 weeks). The recursive partitioning analysis (RPA) class was the only significant prognostic factor identified in multivariate analysis. The median survival for patients in RPA Classes I, II, and III was 72, 48, and 19 weeks, respectively, in Group A and 36 and 13 weeks for Classes II and III in Group B. The number of lesions, tumor volume, whole brain radiotherapy, primary tumor site, age, and sex did not affect survival significantly. CONCLUSIONS: It is suggested that GKS provides an increase in survival time even in patients with a large number (four or more) of metastatic lesions. Concerning the selection of patients for GKS, RPA class should be considered as the most important factor and multiplicity of the lesions alone should not be a reason for withholding GKS.

Adult↗