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Biomedical subjects

Y C Kim

Publications and source records attributed to Y C Kim.

At least 55 records · Page 3Linked to original sources
PubMed2001

Butein, a plant polyphenol, induces apoptosis concomitant with increased caspase-3 activity, decreased Bcl-2 expression and increased Bax expression in HL-60 cells.

In the present study we have investigated whether butein could induce apoptosis in human leukaemic HL-60 cells. The treatment of HL-60 cells with butein induced apoptotic cell death as determined by morphological and biochemical changes. Apoptotic DNA fragments in the butein-treated HL-60 cells were increased gradually as determined by flow cytometric analysis. The caspase-3 activity was increased during butein-induced apoptosis. However, caspase-3 inhibitor abrogated the butein-induced DNA fragmentation. Furthermore, the treatment of HL-60 cells with butein decreased the expression of Bcl-2 protein, but increased the expression of Bax protein. These results suggest that butein-induced apoptosis is mediated through the activation of caspase-3 and it is associated with changed expression of Bcl-2 and Bax proteins.

Apoptosis↗
PubMed2001

Benign glandular schwannoma.

Glandular schwannoma is a rare variant of schwannoma characterized by the presence of glands in an otherwise typical schwannoma. We report a patient with benign glandular schwannoma occurring on the scalp, a site not previously reported. Histologically, a well-defined, encapsulated oval nodule was observed in the subcutaneous tissue. The nodule was composed of a spindle cell component and glandular structures. The spindle cell component stained positively for S-100 protein. All of the glandular epithelium stained with CAM 5.2 and epithelial membrane antigen but not with S-100 protein. The glandular epithelium was focally positive for carcinoembryonic antigen. The histogenesis of the glandular elements in these tumours is still debated. The variable size of the glandular structures in our case was evidence against an entrapped normal sweat gland origin. The glandular epithelium did not stain with S-100 protein at all, but stained with CAM 5.2, which did not support a direct metaplastic origin of the epithelial elements from the schwannian component. A few scattered CAM 5.2-positive cells and microglandular structures in our case may be the initial differentiating epithelial elements possibly derived from pluripotential neural crest cells.

Adult↗
PubMed2001

Ecthyma gangrenosum without bacteraemia in a leukaemic patient.

Ecthyma gangrenosum is a well recognized cutaneous manifestation of Pseudomonas aeruginosa infections in immunocompromised patients. Most cases of ecthyma gangrenosum have been associated with concomitant septicaemia. However, ecthyma gangrenosum rarely develops due to Ps. aeruginosa in the absence of bacteraemia. We report a rare case of a nonsepticaemic form of ecthyma gangrenosum presenting as a large solitary necrotic ulcer in a patient with acute myelogenous leukaemia. A culture from the lesion revealed the presence of Ps. aeruginosa, but the results of repeated blood cultures were negative. Histological examination revealed numerous tiny eosinophilic bacilli in the dermis and panniculus with Gram's stain.

Acute Disease↗
PubMed2001

Neuroprotective dibenzylbutyrolactone lignans of Torreya nucifera.

The methanolic extract of the bark of Torreya nucifera Sieb. et Zucc. (Taxaceae) significantly protected primary cultures of rat cortical cells exposed to the excitotoxic amino acid, L-glutamate. (-)-Arctigenin (1), (-)-traxillagenin (2), arctiin (4), traxillaside (5), and a newly-reported compound 3 (-)-4'-demethyltraxillagenin [(2R,3R)-2-(4''-hydroxy-3''-methoxybenzyl)-3-(4'-hydroxy-3',5'-dimethoxybenzyl)-butyrolactone] were isolated by bioactivity-guided fractionation and further separation using chromatographic techniques. These lignans and their glycosides had significant neuroprotective activities against glutamate-induced toxicity in primary cultures of rat cortical cells at concentrations ranging from 0.01 microM to 10.0 microM.

Animals↗
PubMed2001

Effect of an extract of the root of Scutellaria baicalensis and its flavonoids on aflatoxin B1 oxidizing cytochrome P450 enzymes.

The inhibition of aflatoxin B1 (AFB1) metabolism by a water extract of the root of Scutellaria baicalensis and its flavonoids was examined in liver microsomes. AFB1 is known to be metabolized to aflatoxin M1 (AFM1), aflatoxin Q1 (AFQ1), and AFB1-8,9-epoxide (AFBO). The water extract potently inhibited the production of AFM1 by cytochrome P450 (CYP)1A1/2 and slightly reduced AFBO formation by CYP1A1/2, CYP2B1, CYP2C11 and CYP3A1/2 in TCDD-treated rat liver microsomes. IC50 values for AFM1 and AFBO formation were 6.8 and 122.4 microg/ml, respectively. Wogonin showed the highest inhibitory activity towards AFM1 formation among the flavonoids isolated from the extract. On the other hand, the extract had no effects on the formation of AFBO and AFQ1 in human liver microsomes, and on the activities of CYP2B1, CYP2C11 and CYP3A1/2 which were detected by hydroxylation patterns of testosterone. These results demonstrated that the extract of the root of Scutellaria baicalensis has a specific inhibitory effect on CYP1A1/2 among CYP enzymes involved in AFB1 metabolism by rat and human microsomes.

Aflatoxin B1↗
PubMed2001

Bakuchiol: a hepatoprotective compound of Psoralea corylifolia on tacrine-induced cytotoxicity in Hep G2 cells.

Bioassay-guided fractionation of the H(2)O extract of the seeds of Psoralea corylifolia furnished one hepatoprotective compound, bakuchiol (1), together with two moderately active compounds, bakuchicin (2) and psoralen (3), on tacrine-induced cytotoxicity in human liver-derived Hep G2 cells. The EC(50) values of compounds 1 - 3 are 1.0, 47.0, 50.0 microg/ml, respectively. Silymarin as a positive control showed the EC(50) value with 5.0 microg/ml.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Diarylheptanoids with free radical scavenging and hepatoprotective activity in vitro from Curcuma longa.

Assay-guided fractionation of the EtOAc soluble fraction of the rhizomes of Curcuma longa furnished three DPPH free radical scavenging diarylheptanoids, curcumin (1), demethoxycurcumin (2), and bisdemethoxycurcumin (3). Compounds 1-3 showed the DPPH radical scavenging effects with IC(50) values of 2.8, 39.2, 308.7 microM, respectively. L-Ascorbic acid and resveratrol as positive controls exhibited IC(50) values of 22.5 and 25.0 microM, respectively. Compounds 1-3 showed significant hepatoprotective effects on tacrine-induced cytotoxicity in human liver-derived Hep G2 cells. The EC(50) values of 1-3 are 86.9, 70.7, and 50.2 microM, respectively. Silybin (EC(50) = 69.0 microM) and silychristin (EC(50) = 82.7 microM) were used as positive controls.

Coumaric Acids↗
PubMed2001

Involvement of cyclic GMP in nitric-oxide-induced gastric relaxation Comparison of the actions of cyclic GMP and cyclic AMP.

BACKGROUND: Smooth muscle relaxation induced by various agents that increase the cellular levels of cyclic nucleotides (cAMP and cGMP) is accompanied by a decrease in intracellular Ca2+ concentration. However, little is known about the differences between the inhibitory effects of cAMP and cGMP on the contraction of smooth muscle. OBJECTIVE: To compare the effects and underlying mechanisms of cAMP and cGMP on the inhibition of gastric smooth muscle contraction, cyclic nucleotide promoting agents, as well as cell membrane permeable cyclic nucleotides were used. METHODS: Isometric contraction was measured from circular muscle strips prepared from the fundus of cat stomach in a cylinder-shaped chamber filled with Krebs-Ringer solution (pH 7.4, temperature 36 degrees C) bubbled with 5% CO2 in O2. The level of inositol phosphates (IPs) was measured. RESULTS: Forskolin and sodium nitroprusside significantly inhibited acetylcholine (ACh)-induced gastric smooth muscle contraction and increased the cellular levels of cAMP and cGMP, respectively. Direct application of 8-Br-cAMP and 8-Br-cGMP also significantly inhibited ACh-induced contraction. Both verapamil and TMB-8 inhibited ACh-induced contraction. The combined inhibitory effect of verapamil and TMB-8 was significantly greater than the effect of either one, separately. Forskolin or sodium nitroprusside similarly augmented the effect of verapamil. However, the inhibitory effect of TMB-8 was augmented only by 8-Br-cGMP or sodium nitroprusside but not by 8-BrcAMP or forskolin. Forskolin and 8-Br-cAMP significantly inhibited the formation of inositol phosphates stimulated by ACh. CONCLUSIONS: cAMP inhibits the contraction mechanism associated with intracellular Ca2+ mobilization as well as extracellular Ca2+ influx, while cGMP inhibits contraction by inhibiting the mechanism associated with extracellular Ca2+ influx.

Acetylcholine↗
PubMed2001

Signet ring cell basal cell carcinoma: a basal cell carcinoma with myoepithelial differentiation.

Basal cell carcinoma (BCC) can show a variety of routes of differentiation, but myoepithelial differentiation has rarely been described. We describe a case of BCC showing histologic and immunohistochemical features of myoepithelial differentiation. Histologically, the lesion showed well-demarcated tumor nodules composed of two different components. One component was typical of BCC, and the other component was composed of tumor cells containing abundant cytoplasm, eccentric nuclei, and no peripheral palisading, with scattered signet ring-shaped cells. Immunohistochemically, the tumor cells in the typical BCC component stained with CKAE1/AE3 and smooth muscle actin (SMA), but not with S-100 protein. They stained weakly with CAM5.2, epithelial membrane antigen, and glial fibrillary acidic protein (GFAP). The tumor cells in the other component stained strongly with CKAE1/AE3 and SMA, moderately with epithelial membrane antigen and GFAP, and weakly with CAM5.2. In a small area, the tumor cells stained with S-100 protein.

Aged↗
PubMed2001

Competitiveness in root colonization by Pseudomonas putida requires the rpoS gene.

The rpoS gene in Pseudomonas putida was essential for plant root colonization under competitive conditions from other microbes. The RpoS- mutant survived less well than the wild-type strain in culture medium, and unlike the wild-type, failed to colonize the roots in a peat matrix containing an established diverse microflora. The RpoS-deficient P. putida isolate was generated by insertion of a glucuronidase-npt cassette into the rpoS gene. The RpoS mutant had dose-dependent increased sensitivity to oxidative stress and produced Mn-superoxide dismutase activity earlier than the parent. While extracts from wild-type P. putida stationary-phase cells contained three isozymes of catalase (CatA, CatB, and CatC), the sigma38-deficient P. putida lacked CatB. These results are consistent with previous findings that CatB is induced in stationary-phase.

Bacterial Proteins↗
PubMed2001

New tetrahydrofuran-type sesquilignans of Saururus chinensis root.

Three new tetrahydrofuran-type sesquilignans, called saucerneol A, saucerneol B and saucerneol C were isolated from the underground parts of Saururus chinensis (Saururaceae), together with known lignans, di-O-methyltetrahydrofuriguaiacin B, machilin D and machilin D 4-methyl ether. Their structures were established from several spectral data.

Furans↗
PubMed2001

The properties of carbachol-activated nonselective cation channels at the single channel level in guinea pig gastric myocytes.

We investigated the properties of carbachol (CCh)-activated nonselective cation channels (NSC(CCh)) at the single channel level in the gastric myocytes of guinea pigs using a magnified whole-cell mode or an outside-out mode. The channel activity (NPo) recorded in a magnified whole-cell mode increased with depolarization (from -120 to -20 mV) and had the half activation potential of -81 mV under the symmetrical 140 mM Cs+ condition. The single channel conductance depended upon the extracellular monovalent cations with the order of Cs+ (35 pS) > Na+ (25 pS) > Li+ (21 pS). The channel activities markedly diminished or disappeared when external Cs+ was replaced with Na+ or N-methyl-D-glucamate (NMDG+). With Cs+ and Na+ as external cations, the channel showed a monotonic increase in NPo with the increased mole fraction of Cs+ over Na+, and it had an intermediate conductance value in solution containing 67% Cs+ with 33% Na+. These data suggested that the extracellular monovalent cations regulate the whole-cell current of NSC(CCh) by modulating both the open state probability and the unitary conductance, and there is one binding site for the extracellular cations within the pore.

Animals↗
PubMed2001

The relationship between microvessel count and the expression of vascular endothelial growth factor, p53, and K-ras in non-small cell lung cancer.

Using immunohistochemical staining, we studied the relationship between the microvessel count (MC) and the expression of K-ras, mutant p53 protein, and vascular endothelial growth factor (VEGF) in 61 surgically resected non-small cell lung cancers (NSCLC) (42 squamous cell carcinoma, 14 adenocarcinoma, 2 large cell carcinoma, 2 adenosquamous carcinoma, and 1 mucoepidermoid carcinoma). MC of the tumors with lymph node (LN) metastasis was significantly higher than that of tumors without LN metastasis (66.1+/-23.1 vs. 33.8+/-13.1, p<0.05). VEGF was positive in 54 patients (88.5%). MC was 58.1+/-25.2 (mean+/-S.D.) in a x200 field, and it was significantly higher in VEGF(+) tumors than in VEGF(-) tumors (61.4+/-23.7 vs. 32.9+/-23.8, p<0.05). VEGF expression was higher in K-ras-positive or mutant p53-positive tumors than in negative tumors (p<0.05). MC was significantly higher in K-ras(+) tumors than in K-ras(-) tumors, although it did not differ according to the level of mutant p53 protein expression. Survival did not differ with VEGF, mutant p53, or K-ras expression, or the level of MC. In conclusion, there is a flow of molecular alterations from K-ras and p53, to VEGF expression, leading to angiogenesis and ultimately lymph node metastasis. Correlations between variables in close approximation and the lack of prognostic significance of individual molecular alterations suggest that tumorigenesis and metastasis are multifactorial processes.

Adult↗
PubMed2001

Nurses' assessment of postoperative pain: can it be an alternative to patients' self-reports?

This study was designed to evaluate whether the nurses' assessment of postoperative pain can be an alternative to patients' self-reporting. We examined 187 patients receiving postoperative intravenous patient-controlled analgesia. The nurses assessed the patients' pain with three pain indices (therapeutic efficacy, pain intensity, and facial pain expression) 8 hr after operation. The patients recorded their resting and movement pain using 100-mm visual analog scales immediately following the nurses' assessment. There was an acceptable correlation between overall pain measurement assessed by patients and that assessed by nurses (canonical correlation coefficient=0.72, p=0.0001). The resting pain was more reliably reflected than the movement pain in overall measurement assessed both by nurses and by patients. Among the three pain indices assessed by nurses, the pain intensity most reliably reflected the patients' self-reports. The pain intensity assessed with a simple verbal descriptor scale therefore is believed to be an effective alternative to the patients' self-reports of postoperative pain at rest. However, it mirrored the patients' self-reports during movement less reliably. Therapeutic efficacy and facial pain expression indices were not effective alternatives to patients' self-reporting.

Analgesia, Patient-Controlled↗
PubMed2001

Lack of cytochrome P450 2E1 (CYP2E1) induction in the rat liver by starvation without coprophagy.

Starvation potentiates the hepatotoxicity of a variety of small molecules, including chlorinated hydrocarbons and nitrosamines, through the induction of CYP2E1. A change in CYP2E1 expression during starvation may also alter the pharmacokinetic profiles of xenobiotics. Northern blot and Western blot analyses revealed that hepatic CYP2E1 was not induced during starvation in rats placed in metabolic or wire-bottom cages in contrast to the induction of CYP2E1 in animals housed in solid-bottom cages. We studied the effect of coprophagy on the expression of hepatic CYP2E1 during starvation. The extent of coprophagy was 24% in fed rats. Fecal matter of starving rats was reduced to 14% of control and starving rats re-ingested ~1.6 g of feces per day. The effect of fecal matter on CYP2E1 expression (i.e., 1.6 g/kg/day for 3 days) was assessed in fed or starving rats. Starving rats gavaged with fecal matter for 3 days resulted in a 3.5-fold increase in the level of CYP2E1 mRNA, while fed rats gavaged with feces failed to show an increase in the mRNA. The increase in the CYP2E1 mRNA level accompanied the induction of CYP2E1. Starving rats gavaged with methanol extract of feces (500 mg/kg/day for 3 days) showed a 3.3-fold increase in CYP2E1 mRNA level in the liver. These results provide evidence that CYP2E1 is not induced by starvation without coprophagy, raising the contention that the mechanistic basis for CYP2E1 induction by starvation should be reevaluated.

Animals↗
PubMed2001

A lipogenic diet in mice with a disruption of the stearoyl-CoA desaturase 1 gene reveals a stringent requirement of endogenous monounsaturated fatty acids for triglyceride synthesis.

Stearoyl-CoA desaturase (SCD) catalyzes the de novo biosynthesis of oleate and palmitoleate, which are the major fatty acids found in triglycerides, cholesteryl esters, and phospholipids. A high carbohydrate (lipogenic) diet induces lipogenic gene expression by sterol regulatory element binding protein 1 (SREBP-1c)-mediated gene transcription, leading to an increase in the synthesis of triglycerides. The lipogenic diet fed to mice with a null mutation in the SCD1 gene (SCD-/-) fails to induce the synthesis of triglycerides in liver, despite the induction of expression of SREBP-1 and its target genes, fatty acid synthase and glycerol-3-phosphate acyltransferase. The lipogenic diet led to a decrease in the levels of triglyceride, but an increase in the level of cholesteryl esters of saturated fatty acids. Feeding a lipogenic diet supplemented with high levels of oleate to the SCD-/- mice resulted in incorporation of oleate in the liver of SCD-/- mice, but failed to restore triglycerides to the levels in the normal mouse. Triglyceride synthesis, as measured by the incorporation of [(3)H]glycerol, was dramatically reduced in the liver of SCD-/- mouse fed a lipogenic diet compared with the normal mouse. These observations demonstrate that induction of triglyceride synthesis is highly dependent on SCD1 gene expression.

Animals↗