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Biomedical subjects

J H Sung

Publications and source records attributed to J H Sung.

At least 19 recordsLinked to original sources
PubMed2005

Comment on "Preparation and electrorheological property of rare earth modified amorphous Ba(x)Sr(1-x)TiO3 gel electrorheological fluid".

The comments on the recent results on electrorheological (ER) property of rare earth modified amorphous barium strontium titanate gel based ER fluid are given via analysis of its dynamic yield stress data as a function of applied electric field strengths. Using our previously reported universal yield stress equation, we obtained the critical electric field strength and collapsed their data onto a single curve.

Journal Article↗
PubMed2005

Delayed occurrence of intracranial supratentorial chondroma following compound depressed skull fracture.

We describe an exceptional case of a frontal convexity chondroma arising at the site of a compound depressed skull fracture operated on 12 years earlier. We conclude that intracranial chondroma should be included in the differential diagnosis of a calcified mass for the patients who had had a compound, depressed skull fracture along the suture line, especially in cases of dural laceration by the fragmented bone.

Adolescent↗
PubMed2005

Effects of Panax ginseng extract on exercise-induced oxidative stress.

AIM: This study was designed to study the effects of Panax ginseng extract (PGE) on lipid peroxidation and scavenger enzymes induced by an acute exhaustive exercise in sedentary humans. METHODS: Seven healthy male subjects performed 2 exhaustive incremental exercises on the treadmill before and after 8 weeks' PGE ingestion (2 g each time, 3 times a day) as the control and PGE exercise, respectively. VO2, HR, and exercise duration during exercise were measured. Blood samples were collected at rest, and immediately, 10 and 30 min after each test and used to measure malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD). RESULTS: PGE administration significantly increased exercise duration until exhaustion by 1.5 min (p<0.05). MDA was significantly elevated following both trials (p<0.01), however, it was attenuated after PGE administration (p<0.01). CAT and SOD activities following exercise were significantly elevated, but the activities following control exercise were much lower than those following PGE exercise. CONCLUSIONS: These results suggest that the elevation in CAT and SOD activities as scavenger enzymes after PGE administration result in decrease of MDA level as one of PGE action mechanisms and consequently, prolong exercise duration until exhaustion. These findings support scientific claims that ginseng has ergogenic properties in facilitating recovery from exhaustive exercise.

Adolescent↗
PubMed2003

Wave-front phase measurements of high-order harmonic beams by use of point-diffraction interferometry.

We report the wave-front phase measurement of high-order harmonics employing point-diffraction interferometry. The high-order harmonics generated in a gas-filled hollow tube showed excellent spatial coherence over nearly the whole cross section of the harmonic beams. Using this coherent harmonic source in the extreme-ultraviolet-soft-x-ray region, we have demonstrated the operation of a point-diffraction interferometer and measured the wave-front phase of high-order harmonics.

Journal Article↗
PubMed2001

Effects of the beta-amyloid and carboxyl-terminal fragment of Alzheimer's amyloid precursor protein on the production of the tumor necrosis factor-alpha and matrix metalloproteinase-9 by human monocytic THP-1.

To explore the direct role of beta-amyloid (Abeta) and carboxyl-terminal fragments of amyloid precursor protein in the inflammatory processes possibly linked to neurodegeneration associated with Alzheimer's disease, the effects of the 105-amino acid carboxyl-terminal fragment (CT(105)) of amyloid precursor protein on the production of tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase-9 (MMP-9) were examined in a human monocytic THP-1 cell line and compared with that of Abeta. CT(105) elicited a marked increase in TNF-alpha and MMP-9 production in the presence of interferon-gamma in a dose- and time-dependent manner. Similar patterns were obtained with Abeta despite its low magnitude of induction. Autocrine TNF-alpha is likely to be a main mediator of the induction of MMP-9 because the neutralizing antibody to TNF-alpha inhibits MMP-9 production. Genistein, a specific inhibitor of tyrosine kinase, dramatically diminished both TNF-alpha secretion and subsequent MMP-9 release in response to CT(105) or Abeta. Furthermore, PD98059 and SB202190, specific inhibitors of ERK or p38 MAPK respectively, efficiently suppressed CT(105)-induced effects whereas only PD98059 was effective at reducing Abeta-induced effects. Our results suggest that CT(105) in combination with interferon-gamma might serve as a more potent activator than Abeta in triggering inflammatory processes and that both tyrosine kinase and MAPK signaling pathways may represent potential therapeutic targets for the control of Alzheimer's disease progression.

Alzheimer Disease↗
PubMed2001

Protective effect of glutathione in HIV-1 lytic peptide 1-induced cell death in human neuronal cells.

To elucidate the pathogenic mechanisms involved in neurodegeneration in AIDS patients with cognitive deficits, we have examined the toxic effect of the lentivirus lytic peptide 1 (LLP-1) corresponding to the carboxyl terminus of HIV-1 transmembrane glycoprotein gp41 on human neuronal and glial cell lines. LLP-1 induced a significant lactate dehydrogenase (LDH, a marker of cell death) release from these cells in a concentration- and time-dependent manner, while the noncytolytic LLP-1 analog 2 had little effect. Application of LLP-1 to SH-SY5Y, a well-characterized human neuronal cell line, caused the decline of intracellular glutathione (GSH) content that appeared to occur before a significant LDH release. Furthermore, LLP-1 elicited a significant loss of mitochondrial function as measured by mitochondrial transmembrane potential (MTP). Among the reducing agents and antioxidants tested, GSH and a GSH prodrug N-acetylcysteine (NAC) provided protection against LLP-1-induced neuronal cell death, evidently by restoring the intracellular GSH levels and blocking the disruption of mitochondrial integrity. Thus, gp41-derived LLP-1 may be a potential neurotoxic agent capable of causing the intracellular GSH depletion and disturbing the mitochondrial function, possibly contributing to the neurodegenerative cascade as seen in HIV-1-associated dementia. Our data indicate that restoring both GSH concentration and mitochondrial function may hold promise as possible therapeutic strategies for slowing disease progression of dementia in AIDS patients.

AIDS Dementia Complex↗
PubMed2001

Effect of somatostatin on cholecystokinin-induced amylase release in rat pancreatic acini.

The effect of somatostatin on cholecystokinin-induced amylase release was investigated in isolated rat pancreatic acini. Acini were isolated by enzymatic digestion and incubated in a HEPES buffered Ringer's solution with testing reagents for 30 minutes at 37 degrees C. The activity of released amylase, cAMP, and inositol phosphate formation were measured. Intracellular calcium concentration ([Ca2+]i) was also checked. Somatostatin 14 and octreotide, a somatostatin analog, inhibited CCK-stimulated amylase release in a concentration-dependent manner. The inhibitory effect of octreotide on CCK-induced amylase release was not shown when the acini were treated with 8-Br-cAMP, irrespective of the presence of IBMX. Forskolin potentiated CCK-induced amylase release and this effect was blocked by octreotide treatment; although CCK-8 (3 x 10(-11) M) failed to stimulate cAMP formation, octreotide significantly inhibited basal cAMP formation in the acini. The increase of [Ca2+]i in response to CCK was inhibited by octreotide. However, CCK-induced inositol phosphate formation was not changed by 10(-9) M octreotide. Octreotide had no effect on CCK-stimulated tyrosine phosphorylation, and tyrosine phosphatase inhibitors (NaF and Na2WO4) did not influence the effect of octreotide on CCK-induced amylase release. From these results, we conclude that octreotide inhibits CCK-induced amylase release by inhibiting basal cAMP formation and decreasing the [Ca2+]i stimulated by CCK.

1-Methyl-3-isobutylxanthine↗
PubMed2001

Purification and characterization of ginsenoside Rb1-metabolizing beta-glucosidase from Fusobacterium K-60, a human intestinal anaerobic bacterium.

Fusobacterium K-60, a ginsenoside Rb1-metabolizing bacterium, was isolated from human intestinal feces. From this Fusodobacterium K-60, a ginsenoside Rb1-metabolizing enzyme, beta-glucosidase, has been purified. The enzyme was purified to apparent homogeneity by a combination of butyl-Toyopearl, hydroxyapatite ultragel, Q-Sepharose, and Sephacryl S-300 HR column chromatographies with a final specific activity of 1.52 micromol/min/mg. It had optimal activity at pH 7.0 and 40 degrees C. The molecular mass of this purified enzyme was 320 kDa, with 4 identical subunits (80 kDa). The purified enzyme activity was inhibited by Ba++, Fe++, and some agents that modify cysteine residues. This enzyme strongly hydrolyzed sophorose, followed by p-nitrophenyl beta-D-glucopyranoside, esculin, and ginsenoside Rb1. However, this enzyme did not change 20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol (IH-901) to 20(S)-protopanaxadiol, while it weakly changed ginsenoside Rb1 to IH-901. These findings suggest that the Fusobacterial beta-glucosidase is a novel enzyme transforming ginsenoside Rb1.

Fusobacterium↗
PubMed2000

Induction of apoptosis by a novel intestinal metabolite of ginseng saponin via cytochrome c-mediated activation of caspase-3 protease.

Ginseng saponins exert various important pharmacological effects with regard to the control of many diseases including cancer. The novel intestinal bacterial metabolites of ginseng protopanaxadiol saponins have recently been found and isolated after the oral administration of ginseng extract in human and rats. 20-O-(beta-D-Glucopyranosyl)-20(S)-protopanaxadiol (IH-901) formed from ginsenosides Rb1, Rb2, and Rc is of particular interest in cancer chemoprevention and treatment. We investigated the effects of IH-901 on the human myeloid leukemia cell line HL-60 in terms of inhibition of proliferation and induction of apoptosis. IH-901 showed a significant cytotoxic activity in HL-60 cells (IC(50) = 24. 3 microM) following a 96-hr incubation. Treatment of HL-60 cells with IH-901 resulted in the formation of internucleosomal DNA fragments. The dose- and time-dependent induction of apoptosis by IH-901 was demonstrated in sandwich enzyme immunoassay and the results were confirmed by flow cytometric analysis. Morphological examination of IH-901-treated samples showed cells with chromatin condensation, cell shrinkage, and nuclear fragmentation, all typical characteristics of apoptotic cells. The treatment of HL-60 cells with IH-901 caused activation of caspase-3 protease and subsequent proteolytic cleavage of poly(ADP-ribose) polymerase. IH-901 did not affect the expression of antiapoptotic protein Bcl-2 but did cause a release of mitochondrial cytochrome c into cytosol. In conclusion, our results demonstrate that IH-901 dramatically suppresses HL-60 cell growth by inducing programed cell death through activation of caspase-3 protease, which occurs via mitochondrial cytochrome c release independently of Bcl-2 modulation. These results may provide a pivotal mechanism for the use of IH-901 in the prevention and treatment of leukemia.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Inconsistency between severe substantia nigra degeneration with Lewy bodies and clinical parkinsonism in dementia patients: a cliniconeuropathological study.

In a retrospective cliniconeuropathological study, we reviewed all the cases received in our dementia brain bank during a 4-year period to determine if all patients with severe substantia nigra (SN) degeneration and SN Lewy bodies (LBs) exhibited prominent signs of parkinsonism and were treated for parkinsonism during the disease course. The SN of 426 cases were graded for microscopic degeneration using a semiquantitative five-tiered scale, with grade 0 indicating normal and grade 4 the most severe degeneration. Twenty-nine cases with grade 3 (16) or grade 4 (13) SN degeneration with SN LBs and clinical records were identified. Ten had been treated for parkinsonism (6 grade 3, 4 grade 4) and 19 had not. Whereas most of the patients had exhibited signs of end-stage parkinsonism during their last year, 1 grade 3 and 2 grade 4 patients apparently never exhibited prominent signs of parkinsonism during the course of their dementia. No clear neuropathological differences were noted between these patients that did not have prominent signs and a control group of six patients with clinical Parkinson's disease with dementia (parkinsonism onset at least 1 year before dementia onset). We conclude that in patients with dementia there is an inconsistent relationship between the expression of clinical parkinsonism during life and severe SN degeneration with LBs identified at necropsy.

Aged↗
PubMed2000

Assessing health-related quality of life in cataract patients: the relationship between utility and health-related quality of life measurement.

The relationship between health-related quality of life (HQL) measures and patient preference for their health status was studied. Study subjects consisted of 132 patients at four hospitals who were scheduled for cataract surgery. Generic and disease-specific health status measures were determined in study subjects. The Medical Outcomes Study Short-form 36 (SF-36) item health status instrument was used to measure generic health status and the Visual Function 14 (VF-14) item visual health status instrument was used as the disease-specific health measure. Preference for general health and visual health was measured by assessing utilities assigned by patients to certain health states. Utilities assigned for general health were correlated with all categories of the SF-36 and VF-14 scores. Utilities assigned for visual health were correlated with four categories of the SF-36 (role limitation due to emotional health, general health, physical functioning, and vitality) and VF-14 scores. Utilities assigned for visual health were more strongly correlated with VF-14 scores than generic measures of health. Verbal ratings for visual health were correlated with Snellen visual acuity (SVA) (r = 0.20), utilities assigned for visual health (r = 0.58), VF-14 scores (r = 0.74), all categories of the SF-36 (r values ranging from 0.21 to 0.28), utilities assigned for general health (r = 0.19), and verbal ratings for general health (r = 0.29). Utility measures and verbal ratings for general and visual health were shown to be appropriate HQL measures. These measures were strongly correlated with other established generic and disease-specific health measures and should be included in the array of health status measures.

Activities of Daily Living↗
PubMed1999

Antitumor activity of a novel ginseng saponin metabolite in human pulmonary adenocarcinoma cells resistant to cisplatin.

The in vitro antitumor activity of a novel ginseng saponin metabolite, 20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol (IH-901), was examined against four human cancer cell lines and one subline resistant to cisplatin (CDDP). The growth inhibitory activity of the compound was estimated by MTT tetrazolium assay. The mean concentrations of IH-901 needed to inhibit the proliferation of the cells by 50% (IC50) were 24.3, 25.9, 56.6 and 24.9 microM against human myeloid leukemia (HL-60), pulmonary adenocarcinoma (PC-14), gastric adenocarcinoma (MKN-45) and hepatoma (HepG2) cell lines, respectively. These values are higher than that of CDDP. In the CDDP-resistant PC/DDP cell line, the IC50 values of IH-901 and CDDP were 20.3 and 60.8 microM, respectively. These results suggest that IH-901 is not cross-resistant to CDDP in this cell line and could be a candidate for the treatment of CDDP resistant pulmonary cancer.

Adenocarcinoma↗
PubMed1999

Cytotoxic constituents from Solidago virga-aurea var. gigantea MIQ.

Activity-guided fractionation of the whole plant of Solidago virga-aurea var. gigantea M(IQ). (Compositae) has led to the isolation of three cytotoxic compounds, erythrodiol-3-acetate (1), alpha-tocopherol-quinone (2), and trans-phytol (3) from the hexane soluble fraction. It is the first report of those compounds from the genus.

Antineoplastic Agents↗
PubMed1999

Clinical parkinsonism in dementia patients with substantia nigra Lewy bodies.

In a retrospective clinicopathological study, we examined the substantia nigra (SN) of 48 dementia patients with SN Lewy bodies (LBs) to determine if the severity of degeneration correlated with either the occurrence of signs of parkinsonism at dementia presentation or with the frequency of treatment for parkinsonism during the disease course. The SN specimens were graded for microscopic degeneration using a semi-quantitative five-tiered scale. Whereas no correlation was found between the grade of degeneration and occurrence of signs at presentation (r = -0.16, p = 0.18), with 16 of 38 patients having had signs reported, a more severe grade was statistically correlated with an increased frequency of treatment during the course (r = 0.41, p = 0.004), with ten of 41 patients having been treated for parkinsonism. Contrary to our expectations, we found that fewer than half of the patients with the two most severe grades of degeneration presented with signs of parkinsonism or were ever treated for parkinsonism.

Aged↗
PubMed1998

In vitro antigenotoxic activity of novel ginseng saponin metabolites formed by intestinal bacteria.

Ginseng saponin metabolites produced by human intestinal bacteria were evaluated for antigenotoxic properties by testing their effects on benzo[a]pyrene (B[a]P)-induced mutagenicity and clastogenicity. They include 20-O-(beta-D-glucopyranosyl)-20(S)-protopanaxadiol (IH-901), 20-O-(alpha-D-arabinopyranosyl(1-->6)-beta-D-glucopyranosyl]- 20(S)-protopanaxadiol (IH-902) and 20-O-[alpha-D-arabinofuranosyl(1-->6)-beta-D-glucopyranosyl]-20(S)- protopanaxadiol (IH-903). IH-901, IH-902 and IH-903 inhibited the mutagenicity of B[a]P in a dose-dependent manner. In the chromosome aberration assay, IH-901 and IH-903 reduced the frequency of chromosome aberration induced by B[a]P. These results suggest that the ginseng saponin metabolites tested in the present study have potential as chemopreventive agents.

Animals↗
PubMed1997

Comparison of various expression plasmids for the induction of immune response by DNA immunization.

Intramuscular injection of plasmid DNA is an efficient method to introduce a foreign gene into a live animal. We investigated several factors affecting the gene transfer efficiency and the following immune response by intramuscular injection of plasmid DNA. When the strength of several highly efficient viral promoters was compared in muscle by using the chloramphenicol acetyltransferase (CAT) gene as an indicator, cytomegalovirus (CMV) immediate early promoter was found to be stronger than any other viral promoters including Rous sarcoma virus (RSV), murine leukemia virus (SL3-3) and simian virus 40 (SV40) early promoters. Inclusion of adenovirus tripartite leader (TPL) sequences and a synthetic intron in the 5' untranslated region of mRNA moderately stimulated the CAT expression. On the other hand, the expression of encephalomyocarditis virus (EMCV) VP1 gene was greatly enhanced by the TPL sequences and an intron. The level of humoral immune response by intramuscular injection of various VP1 expression plasmids was compared. The seroconversion rate was highly dependent on the strength of the expression vector. However, the ratio of IgG1 and IgG2a immune response was not significantly variable depending on the strength of the expression vector. Also, the efficiency of the sindbis virus-based DNA vector was examined for the gene expression and immune response. Although a high level of CAT expression was obtained in muscle by using this system, VP1 was not produced as much as the conventional expression vectors. Furthermore, little humoral immune response was elicited by intramuscular injection of VP1-expressing sindbis vector, suggesting that this system was not superior to the conventional vector for DNA immunization.

Animals↗