Biomedical subjects

Do-Hoon Kim

Publications and source records attributed to Do-Hoon Kim.

At least 19 recordsLinked to original sources

PubMed2006

Correlations between neuronal loss, decrease of memory, and decrease expression of brain-derived neurotrophic factor in the gerbil hippocampus during normal aging.

It is known that the hippocampus has vital functions in learning and memory, behavioral regulation, and activity-dependent synaptic plasticity, and that the hippocampus contains high levels of brain-derived neurotrophic factor (BDNF). In the present study, we followed age-dependent changes of BDNF immunoreactivity and protein level in the gerbil hippocampus to identify the correlation between BDNF and aging. BDNF immunoreactivity and its protein level significantly increased at postnatal month (PM) 12 in the hippocampus and thereafter reduced. At PM 24, BDNF immunoreactivity in the hippocampal CA1 region and dentate gyrus was similar to that in the PM 1 group, whereas BDNF immunoreactivity in the CA2/3 region at PM 24 was higher than that at PM 1. In the PM 24 group, an age-related neuronal loss and the decrease of reference and working memory were observed. In conclusion, our results suggest that observed reduction in BDNF and reference memory may be associated with age-dependent neuronal loss in the hippocampal CA1 region.

Aging↗

PubMed2006

Increased plasma nitric oxide metabolites in suicide attempters.

OBJECTIVE: To evaluate any correlation between plasma levels of nitric oxide metabolites (NO(x)) and suicide attempt. METHOD: Plasma NO(x) levels were measured in 53 patients who had recently attempted suicide, 58 non-suicidal psychiatric patients, and 75 normal controls. The severity of suicidal behaviors was evaluated using Weisman and Worden's Risk-Rescue Rating Scale. RESULTS: Plasma NO(x) levels were significantly higher in suicidal patients than non-suicidal psychiatric patients or normal control subjects (F=11.029, d.f.=2, 183, p<0.001). Among the patients with a diagnosis of major depression, suicidal depressive patients had significantly higher plasma NO(x) levels than non-suicidal depressive patients (t=-3.090, d.f.=84, p=0.003). CONCLUSION: Our study suggests that increased NO production in plasma is associated with suicide attempt, especially in depressive patients.

Adult↗

PubMed2005

The immunoreactivity and activity of adenylate cyclase type I are changed in the hippocampal CA1 region after transient forebrain ischemia in gerbils.

Adenylate cyclase (AC) has a specific sensitivity to Ca2+/calmodulin. AC-I, one of the mediator of learning and memory, plays an important role in signal transduction underlying learning and memory function. In the present study, we found ischemia-related changes of AC-I in the hippocampal CA1 region, but not in the CA2/3 region, after 5 min of transient forebrain ischemia in gerbils. In the sham-operated group, AC-I immunoreactive neurons were detected in pyramidal and non-pyramidal cells in the hippocampus proper. AC-I immunoreactivity was significantly increased at 3 h in the CA1 region after ischemic insult. Thereafter, AC-I immunoreactivity was gradually decreased. Four days after ischemic insult, AC-I-immunoreactive CA1 pyramidal cells in the stratum pyramidale were very few due to delayed neuronal death. The results of Western blot analysis showed that changes of AC-I protein contents were similar to immunohistochemical data after ischemic insult. Gpp(NH)p-dependent AC-I activity in hippocampal CA1 region was not changed in all groups, while Ca2+/calmodulin-dependent AC-I activity in hippocampal CA1 region was significantly decreased 24 h after ischemia-reperfusion. These results suggest that the decrease of AC-I activity may be associated with impairment of neurodevelopment and neuroplasticity including learning and memory although the AC-I immunoreactivity was maintained 24 h postischemic group compared to that of the sham-operated group.

Adenylyl Cyclases↗

PubMed2005

Antioxidant-like protein 1 is altered in non-pyramidal cells and expressed in astrocytes in the gerbil hippocampal CA1 region after transient forebrain ischemia.

In the present study, we observed chronological changes of antioxidant-like protein 1 (AOP-1) in the gerbil hippocampal CA1 region after 5 min of transient forebrain ischemia using immunohistochemistry and western blot. AOP-1 was significantly altered in the CA1 region after transient ischemia. In the sham-operated group, AOP-1 immunoreactivity was detected in pyramidal and non-pyramidal cells of the CA1 region. At 30 min after ischemic insult, AOP-1 immunoreactivity and protein level was decreased in the CA1 region. At 12 h after ischemic insult, AOP-1 immunoreactivity and protein level was highest in this region. At this time, after ischemia, AOP-1 immunoreactivity in non-pyramidal cells was high compared to the sham-operated group. Based on double immunofluorescence study, AOP-1-immunoreactive neurons were identified as GABAergic, which were stained with GAD or parvalbumin. Thereafter, AOP-1 immunoreactivity and protein levels were decreased time-dependently. From 4 days after ischemic insult, AOP 1 immunoreactivity was generally expressed in astrocytes. Five days after ischemic insult, AOP-1 immunoreactivity and protein level was increased again to 1.4 folds compared to that of the sham-operated group. In brief, AOP-1 immunoreactivity was increased in GABAergic non-pyramidal cells in the hippocampal CA1 region at early time after ischemic insult and was expressed in astrocytes at late time after ischemia. This result suggests that AOP-1 may be important role in homeostasis of GABAergic neurons because these neurons are resistant to ischemic damage.

Animals↗

PubMed2005

Inhibitory effects of long-term administration of ferulic acid on astrocyte activation induced by intracerebroventricular injection of beta-amyloid peptide (1-42) in mice.

Accumulating evidence indicates that glial cells are actively involved in the pathogenesis of Alzheimer's disease. We recently reported protective effects of long-term administration of ferulic acid against learning and memory deficit induced by centrally administered beta-amyloid peptide (Abeta)1-42 in mice. In that report, we found that the Abeta1-42-induced increases in immunoreactivities of glial fibrillary acidic protein, the astrocyte marker, and interleukin(IL)-1beta in the hippocampus are also suppressed by pretreatment with ferulic acid. In the present study, we aimed to further characterize the effect of long-term administration of ferulic acid on the centrally administered Abeta1-42-induced activation of glial cells in mice. Mice were allowed free access to drinking water (control) or water containing ferulic acid (0.006%) for 4 weeks, and then Abeta1-42 (410 pmol) was administered via intracerebroventricular injection. Intracerebroventricularly injected Abeta1-42 induced an increase in immunoreactivities of endothelial nitric oxide synthase (eNOS) and 3-nitrotyrosine (3-NT) in the activated astrocytes in the hippocampus. Pretreatment of ferulic acid for 4 weeks prevented the Abeta1-42-induced increase in eNOS and 3-NT immunoreactivities. Administration of ferulic acid per se induced a transient and slight increase in eNOS immunoreactivity in the hippocampus on day 14, which returned to basal levels on day 28. Intracerebroventricularly injected Abeta1-42 also increased interleukin-1alpha(IL-1alpha) immunoreactivity in the hippocampus, which was also suppressed by pretreatment with ferulic acid. These results demonstrate that long-term administration of ferulic acid induces suppression of the centrallly injected Abeta1-42-induced activation of astrocytes which is suggested to underlie the protective effect of ferulic acid against Abeta1-42 toxicity in vivo.

Amyloid beta-Peptides↗

PubMed2004

Effect of Zen Meditation on serum nitric oxide activity and lipid peroxidation.

This study was designed to investigate the effect of Zen Meditation on serum nitric oxide activity (NO) and oxidative stress (lipid peroxidation). The experimental group included 20 subjects who had practiced the Zen Meditation program in Meditation Center located in Seoul, South Korea. The control group included 20 subjects who did not practice any formal stress management technique and were age and sex matched with experimental group. To provide an assessment of nitric oxide production, the serum level of nitrate/nitrite was determined using the Griess reagent. Malondialdehyde (MDA) concentration was measured as a convenient index of lipid peroxidation by thiobarbituric acid (TBA) method. Meditation group showed a significant higher level of serum nitrate+nitrite concentration and a significant reduced level of serum malondialdehyde (MDA) than control group. A comprehensive randomized controlled trial should be performed to prove the causal relationship between meditation and level of nitric oxide or oxidative stress in reducing cardiovascular risk factors.

Case-Control Studies↗

PubMed2004

Correlates of quality of life after stroke.

The relationship between lesion location and quality of life (QOL) in stroke patients has not yet been clearly revealed. The present study was undertaken to investigate the clinical and anatomical correlates which can predict future QOL in stroke patients. The study subjects consisted of 69 consecutive patients with ischemic stroke who were followed up 2 months after the stroke event at the stroke unit. Quality of life was evaluated during the 2-month follow up period after the stroke. Baseline information or data including clinical and anatomical correlates (Beck Depression Inventory, Beck Anxiety Inventory, Barthel's Index, MRI data) at the time of the stroke event were collected by performing a review of each patient's chart and research data files. Severe subcortical gray matter lesion and depressive symptoms in the acute phase of stroke were of importance in predicting low QOL 2 months after stroke.

Activities of Daily Living↗

PubMed2004

Hepatoprotective and free radical scavenging activities of phenolic petrosins and flavonoids isolated from Equisetum arvense.

Hepatoprotective activity-guided fractionation of the MeOH extract of Equisetum arvense L. (Equisetaceae) resulted in the isolation of two phenolic petrosins, onitin (1) and onitin-9-O-glucoside (2), along with four flavonoids, apigenin (3), luteolin (4), kaempferol-3-O-glucoside (5), and quercetin-3-O-glucoside (6). Among these, compounds 1 and 4 exhibited hepatoprotective activities on tacrine-induced cytotoxicity in human liver-derived Hep G2 cells, displaying EC(50) values of 85.8 +/ -9.3 microM and 20.2 +/- 1.4 microM, respectively. Silybin, used as a positive control, showed the EC(50) value of 69.0 +/- 3.3 microM. Compounds 1 and 4 also showed superoxide scavenging effects (IC(50) = 35.3 +/- 0.2 microM and 5.9 +/- 0.3 microM, respectively) and DPPH free radical scavenging effect (IC(50) of 35.8 +/- 0.4 microM and 22.7 +/- 2.8 microM, respectively). These results support the use of this plant for the treatment of hepatitis in oriental traditional medicine.

Cell Line, Tumor↗

PubMed2004

Serum tumor necrosis factor-alpha levels and components of the metabolic syndrome in obese adolescents.

Tumor necrosis factor-alpha (TNF-alpha) seems to be increased in obese subjects, suggesting its role as a proinflammatory cytokine to insulin resistance and metabolic abnormalities in obesity. The aim of this study was to evaluate the relationship between serum TNF-alpha, soluble TNF-alpha receptor 1 (sTNF-R1), TNF-alpha receptor 2 (sTNF-R2), and metabolic syndrome (MS) components and anthropometric indices in obese and non-obese adolescents. A cross-sectional study was performed on obese and non-obese adolescents. We studied 71 adolescents (age, 15 to 16 years old); 39 were obese (obese group; 14 males and 25 females) and 32 were non-obese adolescents (non-obese lean group; 12 males and 20 females). The body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were determined in each subject. The serum TNF-alpha, sTNF-R1, sTNF-R2, fasting plasma glucose (FPG), and lipid profile were also measured. The mean serum TNF-alpha, sTNF-R1, and sTNF-R2 were significantly higher in the obese than the non-obese group (TNF-alpha, 18.15 v 5.88 pg/mL, P < .001; sTNF-R1, 2.01 v 1.40 ng/mL, P < .001; sTNF-R2, 6.06 v 3.70 pg/mL, P < .001). The serum TNF-alpha concentrations were positively correlated with the BMI (TNF-alpha, r = 0.346, P < .05; sTNF-R1, r = 0.624, P < .001; sTNF-R2, r = 0.482, P < .001, respectively) and WC (TNF-alpha, r = 0.525, P < .05; sTNF-R1, r = 0.700, P < .001; sTNF-R2, r = 0.669, P < .001, respectively). The serum TNF-alpha was positively correlated with triglyceride (TG) and DBP, and negatively with high-density lipoprotein-cholesterol (HDLC). The sTNF-R1 and sTNF-R2 were correlated with TG and DBP, and TG, respectively. Obese compared with non-obese adolescents exhibited higher concentrations of TNF-alpha and its soluble receptors, and the higher TNF-alpha concentrations were associated with several components of MS in obese adolescents.

Adolescent↗

PubMed2004

Protection against beta-amyloid peptide-induced memory impairment with long-term administration of extract of Angelica gigas or decursinol in mice.

We investigated the effect of long-term oral administration of ethanolic extract of Angelica gigas Nakai (Umbelliferae) (EAG) or decursinol, a coumarin isolated from A. gigas, on beta-amyloid peptide 1-42 (Abeta(1-42))-induced memory impairment in mice. Mice were allowed free access to drinking water (control) or water containing different concentrations of EAG. After 4 weeks, Abeta(1-42) (410 pmol) was administered via intracerebroventricular injection. Pretreatment of mice with EAG (0.1%) for 4 weeks significantly blocked the Abeta(1-42)-induced impairment in passive avoidance performance. Next, mice were fed with chow mixed with various doses of decursinol for 4 weeks before intracerebroventricular injection of Abeta(1-42) (410 pmol). Pretreatment of mice with decursinol (0.001%, 0.002%, and 0.004%) for 4 weeks significantly attenuated the Abeta(1-42)-induced impairment in passive avoidance performance. Decursinol (0.004%) also significantly blunted the Abeta(1-42)-induced decrease in alternation behavior (spatial working memory) in the Y-maze test without change in general locomotor activity. These findings suggest that EAG or decursinol may have preventive effect against memory impairment related with Abeta of Alzheimer's disease.

Amyloid beta-Peptides↗

PubMed2004

Inhibitory effects of long-term administration of ferulic acid on microglial activation induced by intracerebroventricular injection of beta-amyloid peptide (1-42) in mice.

Flavonoids and monophenolic compounds have been well described in recent years as antioxidants and scavengers of reactive oxygen and nitrogen species. In the present study, we aimed to characterize the effects of long-term administration of ferulic acid on the centrally administered beta-amyloid peptide (Abeta)(1-42)-induced activation of microglial cells in mice. Abeta(1-42) increased the immunoreactivity of OX-42, a microglial marker, and interferon-gamma in the hippocampus at 8 h after the intracerebroventricular injection. The effects were suppressed by long-term (4-week) pretreatment with ferulic acid. This inhibition of microglial cell activation may underlie the beneficial effects of long-term administration of ferulic acid on Abeta(1-42)-induced toxicity in vivo.

Amyloid beta-Peptides↗

PubMed2004

The effects of antidepressant treatment on serum cytokines and nutritional status in hemodialysis patients.

The aim of this study was to investigate the effects of antidepressant treatment on serum cytokines and nutritional status in hemodialysis patients. Twenty-eight hemodialysis patients with a depressed mood were given 20 mg of fluoxetine for 8 weeks. The degree of depressive symptoms, the serum levels of interleukin-1beta, interleukin-2, interleukin-6, tumor necrosis factor-alpha, c-reactive protein, and markers of nutritional status were assessed at baseline and after treatment. The outcome was assessed in terms of response to treatment (>50% reduction in the score of the Hamilton depression rating scale). Antidepressant treatment decreased the serum level of interleukin-beta1 in both response and nonresponse groups, and increased the serum level of interleukin-6 only in the response group. At baseline, the level of interleukin-6 in the response group was lower than in the nonresponse group. Antidepressant treatment also increased fat distribution significantly in the response group which might have slightly improved the nutritional status. This study suggests that antidepressant treatment improve depressive symptoms and may affect immunological functions and nutritional status in chronic hemodialysis patients with depression.

Adult↗

PubMed2003

The inhibitory effect of ginseng saponins on the stress-induced plasma interleukin-6 level in mice.

The effect of ginseng saponins on plasma interleukin-6 (IL-6) in non-stressed and immobilization-stressed mice were investigated. Ginseng total saponins, ginsenosides Rb2, Rg1 and Rd administered intraperitoneally attenuated the immobilization stress-induced increase in plasma IL-6 level. But, intracerebroventricular injection of each ginsenoside did not affect plasma IL-6 level induced by immobilization stress. Ginsenosides Rb2, Rd and Rg1 significantly decreased norepinephrine and/or epinephrine-induced increase of IL-6 level in macrophage cell line (RAW 264.7). Thus, it can be suggested that the inhibitory action of ginseng saponins against the immobilization stress-induced increase of plasma IL-6 level would be in periphery; at least in part, mediated by blocking norepinephrine- and/or epinephrine-induced increase of IL-6 level in macrophage rather than in the brain. Ginseng saponins might be proposed as a possible candidate in the research or therapeutic modulation of stress-related disorders.

Animals↗

PubMed2003

Elevation of Na+-K+ ATPase immunoreactivity in GABAergic neurons in gerbil CA1 region following transient forebrain ischemia.

In a previous study, we suggested that GABAergic neurons might be resistant to ischemic insult, because of the maintenance of the GABA shunt, which is one of the ATP synthetic pathways in neurons. In the present study, we identified Na(+)-K(+) ATPase immunoreactivity in the gerbil hippocampus in order to determine whether changes in Na(+)-K(+) ATPase immunoreactivity correlate with GABA shunt following ischemic insult. At 12 h after ischemia-reperfusion, Na(+)-K(+) ATPase immunoreactivity accumulated in some neurons in the CA1 region. However, the protein content of Na(+)-K(+) ATPase was not altered. Interestingly, the density of Na(+)-K(+) ATPase immunoreactivity in neurons and the protein content in the CA1 region was intensified in the 24 h post-ischemic group. As a result of double immunofluorescence study, Na(+)-K(+) ATPase immunoreactive neurons were identified with GABAergic neurons. Therefore, our findings suggest that the increase of Na(+)-K(+) ATPase in GABAergic neurons may be able to explain the resistance of these cells to ischemic insult, and support our previous hypothesis that GABA may play an important role as a metabolite in the survival of GABAergic neurons after ischemic insult.

Animals↗

PubMed2003

Antinociceptive mechanisms of orally administered decursinol in the mouse.

Antinociceptive profiles of decursinol were examined in ICR mice. Decursinol administered orally (from 5 to 200 mg/kg) showed an antinociceptive effect in a dose-dependent manner as measured by the tail-flick and hot-plate tests. In addition, decursinol attenuated dose-dependently the writhing numbers in the acetic acid-induced writhing test. Moreover, the cumulative response time of nociceptive behaviors induced by an intraplantar formalin injection was reduced by decursinol treatment during the both 1st and 2nd phases in a dose-dependent manner. Furthermore, the cumulative nociceptive response time for intrathecal (i.t.) injection of TNF-alpha (100 pg), IL-1 beta (100 pg), IFN-gamma (100 pg), substance P (0.7 microg) or glutamate (20 microg) was dose-dependently diminished by decursinol. Intraperitoneal (i.p.) pretreatment with yohimbine, methysergide, cyproheptadine, ranitidine, or 3,7-dimethyl-1-propargylxanthine (DMPX) attenuated inhibition of the tail-flick response induced by decursinol. However, naloxone, thioperamide, or 1,3-dipropyl-8-(2-amino-4-chloro-phenyl)-xanthine (PACPX) did not affect inhibition of the tail-flick response induced by decursinol. Our results suggests that decursinol shows an antinociceptive property in various pain models. Furthermore, antinociception of decursinol may be mediated by noradrenergic, serotonergic, adenosine A(2), histamine H(1) and H(2) receptors.

Administration, Oral↗

PubMed2003

Effects of ginseng saponin administered intraperitoneally on the hypothalamo-pituitary-adrenal axis in mice.

Intraperitoneal injection of ginseng total saponin (GTS; 5 and 20 mg/kg) raised plasma corticosterone levels in mice. However, interestingly, pretreatment of animals with the same doses of GTS (5 and 20 mg/kg) significantly attenuated the immobilization stress-induced increase in plasma corticosterone levels. Of the ginsenosides Rb(1), Rb(2), Rc, Rd, Re, Rf, Rg(1), 20(S)-Rg(3), and 20(R)-Rg(3) injected intraperitoneally at doses of 0.1-2 mg/kg, Rc (2 mg/kg) significantly inhibited the immobilization stress-induced increase in plasma corticosterone levels. GTS and Rc administered intraperitoneally did not affect the immobilization stress-induced elevation of plasma adrenocorticotropic hormone (ACTH) level. Pretreatment with GTS and Rc significantly attenuated the increase in plasma corticosterone levels induced by intraperitoneal injection of ACTH (30 microg/kg). These results suggest that GTS and Rc inhibit the immobilization stress-induced increase in plasma corticosterone levels by blocking ACTH action in the adrenal gland. Ginseng may be proposed to be useful for treatment of stress related disorders.

Adrenocorticotropic Hormone↗

PubMed2003

Lead and cadmium levels in daily foods, blood and urine in children and their mothers in Korea.

OBJECTIVES: The present study was initiated to examine the dietary intake, blood level and urinary concentration of lead (Pb) and cadmium (Cd) among children in Korea, in comparison with the findings in their mothers. METHODS: Peripheral blood, spot urine and 24-h food duplicate samples were collected in Busan, Korea, from 38 pairs of children (4-10 years of age) and their mothers (28-46 years, non-smoking, mostly housewives), who provided informed consent. Samples were wet-ashed by being heated in the presence of mineral acids, and Pb and Cd in the wet-ashed samples were analyzed by graphite furnace atomic absorption spectrometry. Pb and Cd in food (Pb-F, Cd-F), blood (Pb-B, Cd-B) and urine [observed value (Pb-Uob, Cd-Uob), and values corrected for creatinine (Pb-Ucr, Cd-Ucr) or a specific gravity (1.016; Pb-Usg, Cd-Usg)] were presented in terms of geometric mean (GM) and geometric standard deviation (GSD). RESULTS: Pb-F and Cd-F in the children were 0.337 microg Pb and 0.457 microg Cd/kg body weight per day as GM, respectively. Pb-B and Cd-B were 38.0 microg Pb and 1.51 microg Cd/l, and Pb-U and Cd-Uob were 5.44 microg Pb/l and 1.33 microg Cd/l, respectively. Pb-F and Pb-B for children were not significantly different from the values for their mothers. In contrast, Cd-F and Cd-B were significantly different between children and their mothers. Cd-F for children correlated with Cd-F for mothers, but no significant correlation was observed in Cd-B, Cd-U, Pb-F, Pb-B or Pb-U between children and their mothers. The dietary intake of Pb in total Pb intake (i.e., respiratory and dietary intake) accounted for 51.7 and 64.8% in children and their mothers, respectively, whereas the corresponding proportions were 97.8 and 98.2%, respectively, for Cd. CONCLUSION: Cd intake was exclusively from food, both in children and mothers. Dietary Cd intake of children significantly correlated with that of their mothers. Dietary Pb intake in children, however, did not correlate with that of their mothers. Pb uptake from ambient air tended to be higher in children than in their mothers.

Adult↗

PubMed2003

Secoiridoid glucosides with free radical scavenging activity from the leaves of Syringa dilatata.

Activity-guided fractionation of the EtOAc and MeOH extract of the leaves of Syringa dilatata NAKAI furnished one free radical scavenger, the secoiridoid glucoside oleuropein together with ligstroside and an iridoid glucoside, syringopicroside. Oleuropein interacted with the stable free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and showed an IC(50) value of 40.4 microM. L-Ascorbic acid as a positive control showed an IC(50) value of 50.3 microM.

Biphenyl Compounds↗