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Biomedical subjects

N Y Kim

Publications and source records attributed to N Y Kim.

At least 37 records · Page 2Linked to original sources
PubMed2000

Inhibitory effects of butanol fraction of the aqueous extract of Forsythia koreana on the nitric oxide production by murine macrophage-like RAW 264.7 cells.

The aim of this study was to investigate the effect of butanol fraction of the aqueous extract of Forsythia koreana fruits on the nitric oxide (NO) production and inducible nitric oxide synthesis (iNOS) gene expression in murine macrophage-like RAW 264.7 cells. Butanol fraction alone affected neither NO production nor iNOS gene expression in macrophage-like RAW 264.7 cells. However, the butanol fraction inhibited NO production and iNOS gene expression in RAW 264. 7 cells stimulated with interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). These findings suggest that inhibition of NO production by this butanol fraction in RAW 264.7 cells stimulated with IFN-gamma plus LPS was due to the suppression of iNOS gene expression.

Analysis of Variance↗
PubMed2000

Antiproliferative effects of alkaloids from Sedum sarmentosum on murine and human hepatoma cell lines.

The whole plant of Sedum sarmentosum (SS) has been traditionally used for the treatment of chronic viral hepatitis in China and South Korea. Certain hepatitis virus causes acute and chronic hepatitis and induces hepatocellular carcinoma (HC). In the present study, we examined whether the crude alkaloid fraction (CAF) of SS had any anticancer effects on hepatoma cell lines. Murine hepatoma (BNL CL. 2) and human hepatoma (HepG2) cell lines were cultured in the presence of CAF of SS at various doses (50-150 microg/ml) for 24 or 48 h. CAF caused a dose-dependent inhibition of cell proliferation without necrosis or apoptosis. Antiproliferative effects of CAF of SS were associated with an increase in the number of cells in the G1 phase of cell cycle. This study suggests that SS may improve survival of hepatoma patients via the inhibition of excessive growth of tumor cells.

Alkaloids↗
PubMed2000

Sedative activity of two flavonol glycosides isolated from the flowers of Albizzia julibrissin Durazz.

The flowers of Albizzia julibrissin are used as a sedative in oriental traditional medicine. The phytochemical study of this plant allowed the isolation of two flavonol glycosides, quercitrin (1) and isoquercitrin (2). The sedative activity of these compounds was evaluated, and both compounds 1 and 2 increased pentobarbital-induced sleeping time in dose-dependent manner in mice. These results support the use of the flowers of this plant as a sedative agent.

Animals↗
PubMed2000

Lavandulylflavonoids: a new class of in vitro apoptogenic agents from Sophora flavescens.

The root of Sophora flavescens has been reported to possess antitumor activity in Sarcoma 180, lymphoid leukemia 1210 and melanotic melanoma. We have isolated four cytotoxic flavonoids with a lavandulyl side-chain at C8 and tested for their effects on human myeloid leukemia HL-60 cells and human hepatocarcinoma HepG2 cells, in terms of inhibition of proliferation and induction of apoptosis. They showed potent antiproliferative effects with IC(50) values from 11.3 microM to 18.5 microM in HL60 cells and from 13.3 microM to 36. 2 microM in HepG2 cells. Treatment of HL-60 cells with the lavandulylflavonoids induced apoptosis in a dose-dependent manner. Apoptosis was judged by the detection of DNA fragmentation by agarose gel electrophoresis and the degree of apoptosis was quantified by a sandwich enzyme immunoassay. The hydration of C4"'C5"' double bond with or without C3 hydroxylation caused a complete loss of cytotoxicity. These results suggest that the lavandulyl side-chain is essential for the activity of the flavonoids isolated from S. flavescens which may be used as cancer chemotherapeutic and chemopreventive agents.

Apoptosis↗
PubMed2000

Cytotoxic lavandulyl flavanones from Sophora flavescens.

Two new lavandulylated flavanones, (2S)-2'-methoxykurarinone (1) and (-)-kurarinone (2), were isolated from the root of Sophora flavescens, together with two known lavandulyl flavanones, sophoraflavanone G (3) and leachianone A (4), and two known isoflavonoids, formononetin and l-maakiain. The structures of 1 and 2 were determined on the basis of optical rotation and spectral evidence and by comparison with known compounds. Compounds 1-4 exhibited cytotoxic activity against human myeloid leukemia HL-60 cells.

Antineoplastic Agents↗
PubMed2000

Diarylheptanoids with in vitro inducible nitric oxide synthesis inhibitory activity from Alnus hirsuta.

Four diarylheptanoids were isolated from the leaf of Alnus hirsuta (Betulaceae) and have been assessed for nitric oxide (NO) production inhibitory effects in vitro. Oregonin (1) and hirsutanonol (2) were found to be potent inducible nitric oxide synthase (iNOS) inhibitors. Compounds 1 and 2 showed inhibition of NO synthesis in dose-dependent manners by murine macrophage-like RAW 264.7 cells stimulated with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS). Their 50% inhibitory concentrations (IC50) were 3.8 and 14.3 microM, respectively. The inhibitory effects of these compounds on NO synthesis were due to suppression of iNOS mRNA expression as determined by Northern blotting.

Animals↗
PubMed2000

Cyclic adenosine monophosphate inhibits quinolone alkaloid evocarpine-induced apoptosis via activation of protein kinase A in human leukaemic HL-60 cells.

Evocarpine, an isoquinolone alkaloid isolated from the fruit of Evodia rutaecarpa, was found to induce apoptotic cell death in promyelocytic leukaemia HL-60 cells in dose- and time-dependent manners. We investigated the involvement of protein kinase A during the evocarpine-induced apoptotic cell death. Evocarpine-induced apoptosis was markedly inhibited by treatment of the cells with dibutyryl-cyclic adenosine monophosphate. Similar results were obtained with other commonly used cyclic adenosine monophosphate analogues, chlorophenylthio-cyclic adenosine monophosphate and the intracellular cyclic adenosine monophosphate-elevating agent, forskolin. In contrast, pretreatment of HL-60 cells with KT5720, an inhibitor of cyclic adenosine monophosphate-dependent protein kinase A, abrogated the protective effects of cyclic adenosine monophosphate analogues and forskolin on evocrpine-induced apoptosis. These findings suggest that cyclic adenosine monophosphate-dependent activation of protein kinase A plays a crucial role in protecting HL-60 cells from the evocarpine-induced apoptotic cell death.

Apoptosis↗
PubMed2000

Interaction of porin from Yersinia pseudotuberculosis with lipopolysaccharides. Effect of ionic strength, pH, and divalent cations on the binding parameters.

Interaction of the pore-forming protein (porin) from Yersinia pseudotuberculosis with S- and R-forms of the endogenous lipopolysaccharide (LPS) was studied at various ionic strengths (20-600 mM NaCl), concentrations of divalent cations (5-100 mM CaCl2, MgCl2), and pH values from 3.0 to 9.0. The interaction of the R-LPS with porin has been shown in all experimental conditions to be in consensus with the model suggesting binding at independent sites of two types. S-LPS binds to interacting sites of relatively high affinity and to independent sites of low affinity at all pH values examined and at low NaCl concentration. The cooperative interaction of the S-LPS and porin is not observed at high ionic strength and in divalent cation-free medium. The number of binding sites of porin and association constants (Ka) for both LPS forms decrease significantly on increasing the solution ionic strength. The Ka values for the R- and S-LPS change oppositely on changing the pH: the Ka value for the R-LPS is maximal (Ka = 6.7 x 10(5) M-1), but that for S-LPS is minimal (Ka = 0.4 x 10(5) M(-1) at pH 5.0-5.5. The number of high-affinity and low-affinity binding sites for both LPS forms is maximal at pH 5.0-5.5. In this case, the numbers of high- and low-affinity sites for R-LPS are 3 and 10, respectively, and those for the S-LPS are 7 and 20, respectively. These data suggest an important role of electrostatic interactions on binding of LPS to porin. The contribution of conformational changes of the ligand and protein and hydrophobic interactions are discussed.

Binding Sites↗
PubMed2000

The comparison of toluene determination between headspace-solid phase microextraction and headspace methods in glue-sniffer's blood and urine samples.

An accurate and simple method was developed to determine the level of toluene in urine and blood quantitatively by using the gas chromatography/mass spectrometry (GC/MS) with headspace--solid phase microextraction (HS-SPME) technique. An assembly of SPME with a replaceable extraction fiber, coated with 100 microm polydimethylsiloxane, was used. The detection limit of toluene in blood and urine with HS-SPME technique was 10 times higher than that with headspace (HS) technique. To compare the HS-SPME with HS technique for the determination of toluene in biological fluids, blood and urine samples from glue sniffers were analyzed by both methods. The level of toluene by the two techniques was highly correlated: the correlation coefficient (r2) between the two sets of values were 0.98 and 0.96 in urine and blood, respectively.

Forensic Medicine↗
PubMed1999

Molecular analysis of rice plants harboring an Ac/Ds transposable element-mediated gene trapping system.

In rice, limited efforts have been made to identify genes by the use of insertional mutagens, especially heterologous transposons such as the maize Ac/Ds. We constructed Ac and gene trap Ds vectors and introduced them into the rice genome by Agrobacterium-mediated transformation. In this report, rice plants that contained single and simple insertions of T-DNA were analysed in order to evaluate the gene-tagging efficiency. The 3' end of Ds was examined for putative splicing donor sites. As observed in maize, three splice donor sites were identified at the 3' end of the Ds in rice. Nearly 80% of Ds elements were excised from the original T-DNA sites, when Ac cDNA was expressed under a CaMV 35S promoter. Repetitive ratoon culturing was performed to induce new transpositions of Ds in new plants derived from cuttings. About 30% of the plants carried at least one Ds which underwent secondary transposition in the later cultures. Eight per cent of transposed Ds elements expressed GUS in various tissues of rice panicles. With cloned DNA adjacent to Ds, the genomic complexities of the insertion sites were examined by Southern hybridization. Half of the Ds insertion sites showed simple hybridization patterns which could be easily utilized to locate the Ds. Our data demonstrate that the Ac/Ds-mediated gene trap system could prove an excellent tool for the analysis of functions of genes in rice. We discuss genetic strategies that could be employed in a large scale mutagenesis using a heterologous Ac/Ds family in rice.

Base Sequence↗
PubMed1999

A sesquiterpene, dehydrocostus lactone, inhibits the expression of inducible nitric oxide synthase and TNF-alpha in LPS-activated macrophages.

Nitric oxide (NO) and tumor necrosis factor alpha (TNF-alpha) are the major mediators produced in activated macrophages which contribute to the circulatory failure associated with septic shock. A sesquiterpene lactone compound (dehydrocostus lactone) isolated from the medicinal plant, Saussurea lappa, inhibited the production of NO in lipopolysaccharide (LPS)-activated RAW 264.7 cells by suppressing inducible nitric oxide synthase enzyme expression. This compound also decreased the TNF-alpha level in LPS-activated systems in vitro and in vivo. Thus, dehydrocostus lactone may be a possible candidate for the development of new drugs to treat endotoxemia accompanied by the overproduction of NO and TNF-alpha.

Animals↗
PubMed1999

In vitro inducible nitric oxide synthesis inhibitory active constituents from Fraxinus rhynchophylla.

Bioassay-guided fractionation of an H2O extract of the barks of Fraxinus rhynchophylla has furnished two inducible nitric oxide synthase (iNOS) inhibitory compounds, ferulaldehyde (1) and scopoletin (3) together with a coumarin, fraxidin (2). Compounds 1 and 3 showed inhibition of nitric oxide (NO) synthesis in a dose-dependent manner by murine macrophage-like RAW 264.7 cells stimulated with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS). The inhibition of NO synthesis of 1 was reflected in the decreased amount of iNOS protein, as determined by Western blotting.

Acrolein↗
PubMed1999

In vitro inducible nitric oxide synthesis inhibitors from Alismatis Rhizoma.

Bioassay-guided fractionation of an aqueous extract of Alismatis Rhizoma has furnished two inducible nitric oxide synthase (iNOS) inhibitory compounds, alismol (1) and alisol B monoacetate (2), together with an inactive triterpene, alisol C monoacetate (3). Compounds 1 and 2 inhibited nitric oxide (NO) synthesis in a dose-dependent manner in murine macrophage-like RAW 264.7 cells stimulated with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS). The inhibitory effects of 1 and 2 on NO synthesis were partly due to suppression of iNOS mRNA expression as determined by Northern blotting.

Animals↗
PubMed1998

Degradation of acharan sulfate and heparin by Bacteroides stercoris HJ-15, a human intestinal bacterium.

When glycosaminoglycan (GAG)-degrading enzymes were measured in normal human stool suspensions, all 5 tested different stools degraded titrable heparin and acharan sulfate. GAG-degrading bacteria were screened from the isolates of human stools. Among them, HJ-15 had the most potent activities of heparinases (GAGs-degrading enzymes). However, HJ-15 produced the enzyme even if in the media without heparin. Acharan sulfate lyase was induced by acharan sulfate and heparin. Heparinase production was also induced by these GAGs. These enzymes, acharan sulfate lyase and heparinase, were produced in exponential and stationary phase of HJ-15 growth, respectively. Optimal pHs of the acharan sulfate lyase and heparinase activities were 7.2 and 7.5, respectively. The biochemical properties of HJ-15 was similar to those of B. stercoris. However, difference from B. stercoris was utilization of raffinose. This HJ-15 also degraded chondroitin sulfates A and C.

Bacteroides↗
PubMed1998

Pigmentary diseases.

Abnormalities of pigmentation are common and frequently produce great concern in patients presenting to primary care physicians. Although many pigmentary changes arise as a consequence of inflammatory skin disorders, it is important to differentiate a primary skin disease from postinflammatory changes. Early recognition of a pigmentary disease allows the clinician to begin appropriate therapy at a stage when medical intervention may be more effective. Although many skin disorders are mainly of cosmetic concern, the condition may be devastating psychologically, requiring the clinician to be sensitive to the overall impact of the disorder and treat it accordingly.

Diagnosis, Differential↗
PubMed1997

Cardioversion dermatitis.

Dermatitis resulting from medical devices is common. The dermatologic hazards of transcutaneous electrical nerve stimulation, cardiac pacemakers, and electrocardiography electrodes are well described. We report a 70-year-old man who experienced contact dermatitis from direct current cardioversion. To our knowledge, this is the first report of cardioversion-associated dermatitis.

Aged↗