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Biomedical subjects

S Y Park

Publications and source records attributed to S Y Park.

At least 19 recordsLinked to original sources
PubMed2006

FDG uptake and glucose transporter type 1 expression in lymph nodes of non-small cell lung cancer.

AIMS: FDG uptake in NSCLC is related to glucose transporter type 1 (Glut-1) expression. Here, we investigated the direct causal relationship between FDG uptake and Glut-1 expression to determine the role of Glut-1 in FDG uptake by malignant and benign lymph nodes (LNs). METHODS: Fifty-five curative lung resections in 53 NSCLC patients (male:female=36:17, age=62.0+/-11.8 years) were included. Maximum standardized uptake values (maxSUVs) of LNs in preoperative whole body FDG-PET and Glut-1 immunostaining results were compared. RESULTS: Of 316 pathologically confirmed LNs, 12.3% (39/316) were malignant, and in malignant LNs, FDG positive LNs were no different from FDG negative LNs in terms of size (15.0+/-6.7 mm vs 10.0+/-6.1mm, p>0.05), or in terms of the proportion of LNs occupied by tumor (60.0+/-28.8% vs 39.2+/-38.4%, p>0.05), but had greater percentages of Glut-1 positive cells in tumors (74.1+/-31.8% vs 22.7+/-18.7%, p<0.01), and Glut-1 staining intensities (3.4+/-0.9 vs 1.8+/-1.3, p<0.01). FDG negative malignant LNs featured cytoplasmic Glut-1 expression and adenocarcinoma. Glut-1 staining intensities were found to be significantly correlated with the maxSUVs of malignant LNs (rho=0.516, p<0.05), but the percentages of Glut-1 positive cells in tumors were not (r=0.2072, p>0.05). Analysis of FDG positive benign LNs showed that maxSUV was not correlated with degree of follicular hyperplasia, or Glut-1 expression (p>0.05). CONCLUSIONS: Intense Glut-1 immunoreactivity was found to be proportionally related to the degree of FDG uptake by malignant LNs in NSCLC. However, the finding that Glut-1 expression in lymphoid hyperplasia showed no correlation with FDG uptake in benign LNs requires further investigation.

Aged↗
PubMed2006

Hyperhydricity in apple: ultrastructural and physiological aspects.

We studied the effects of hyperhydricity on subcellular ultrastructure and physiology of leaves during in vitro regeneration of apple plants. Morphological, anatomical and ultrastructural differences between healthy leaf tissues obtained from greenhouse-grown plants and healthy and hyperhydric leaves obtained from shoots raised from nodal shoot explants in a bioreactor were investigated by electron microscopy and confocal laser scanning microscopy. Compared with healthy leaves, hyperhydric leaves showed abnormal, often discontinuous development of the epidermis and cuticle. Stomata were malformed. The leaf lamina appeared thickened and was characterized by poor differentiation between the palisade and spongy mesophyll tissue. Hyperhydric leaves had a significantly lower chloroplast number per cell and chloroplasts showed reduced thylakoid stacking compared with healthy leaves. Hyperhydricity resulted in a general decrease in concentrations of reduced and oxidized pyridine nucleotides, reflecting a reduction in metabolic activity. The activities of antioxidant enzymes, such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase were higher in hyperhydric leaves than in healthy leaves, indicating that hyperhydricity was associated with oxidative stress. Chlorophyll fluorescence measurements provided evidence of oxidative damage to the photosynthetic machinery in hyperhydric leaves: photochemical efficiency of photosystem II, effective quantum efficiency and photochemical quenching were all lower in hyperhydric leaves compared with healthy leaves.

Antioxidants↗
PubMed2006

Technical note: Improved extraction method with hexane for gas chromatographic analysis of conjugated linoleic acids.

Extraction properties of different solvents (chloroform/methanol, hexane/isopropanol, and hexane) were studied for the gas chromatographic analysis of conjugated linoleic acids (CLA) from probiotic bacteria grown in de Man, Rogosa, and Sharpe medium. As compared with chloroform/methanol and hexane/isopropanol, hexane showed comparable extraction efficiency for CLA from unspent de Man, Rogosa, and Sharpe medium, but showed minimal extraction of oleic acid originated from the emulsifier in broth. The extraction efficiency of CLA by hexane was influenced by the broth pH, showing the optimal pH of 7.0. Repeated extraction with hexane increased the yield. Extraction with hexane showed excellent recovery of spiked CLA from the spent broth with up to 97.2% (standard deviation of 1.74%). This represents the highest recovery of CLA from culture broth ever reported. The sample size was also successfully reduced to 0.5 mL to analyze CLA from the broth without impairment of analytical data. This smaller sample size in the 1.5-mL microcentrifuge tube using a small bench-top centrifuge reduced analytical time significantly.

2-Propanol↗
PubMed2005

Induction of MMP-13 expression by soluble human glucocorticoid-induced tumor necrosis factor receptor in fibroblast-like synovial cells.

OBJECTIVE: We tested the hypothesis that human glucocorticoid-induced tumor necrosis factor receptor (hGITR/TR11) expressed on the surface of activated CD4(+) T cells is responsible for up-regulating the production of matrix metalloproteinase (MMP)-13 by fibroblast-like synoviocytes (FLSs). METHODS: The level of MMP-13 was measured by Western blot and reverse transcriptase polymerase chain reaction (RT-PCR). Expressions of hGITR ligand (hGITRL) on the surface of FLSs and hGITR on the surface of human CD4(+) T cells were analyzed by flow cytometry and RT-PCR. Neutralizing antibodies (Abs) were used to block hGITRL and hGITR on the surface of FLSs and human CD4(+) T cells, respectively. Human CD4(+) T cells were cocultured with FLSs to facilitate interaction between hGITR on CD4(+) T cells and hGITRL on FLSs. RESULTS: Soluble hGITR (shGITR) stimulated FLSs to produce MMP-13, and blockade of hGITRL reduced this effect. Direct contact between activated CD4(+) T and FLSs also induced the production of MMP-13, and neutralization of hGITR on activated CD4(+) T cells during coculture decreased the amount of MMP-13 produced by FLSs. CONCLUSION: shGITR stimulated FLSs to produce MMP-13 via a signal through hGITRL. Direct contact between activated CD4(+) T cells and FLSs facilitated hGITR-hGITRL interaction, and resulted in inducing MMP-13. This effect may increase tissue destruction in chronic inflammation such as rheumatoid arthritis (RA).

Arthritis↗
PubMed2005

Effect of leptin on insulin resistance of muscle--direct or indirect?

We examined the effect of leptin on the insulin resistance in skeletal muscles by measuring glucose transport. Male Wistar rats were fed rat chow or high-fat diets for 30 days. Before sacrifice, rats fed high-fat diet were subcutaneously injected with leptin (1 mg/kg b.w.) for 3 days. The glucose transport in epitrochlearis and soleus muscles did not differ in the experimental groups under basal conditions, however these values decreased significantly in the rats fed high-fat diet under insulin stimulation (p<0.01). Leptin treatment recovered the decreased glucose transport in epitrochlearis (p<0.05) and soleus muscles (p=0.08). Triglyceride concentrations in soleus muscles were increased significantly in the rats fed high-fat diet as compared to rats fed chow diet (p<0.01), and were decreased significantly by leptin treatment (p<0.01). The glucose transport was measured under basal conditions and after 60 microU/ml of insulin treatment with or without 50 ng/ml of leptin. Leptin had no direct stimulatory effect on glucose transport under both basal and insulin-stimulated conditions in vitro. These results demonstrate that leptin injection to rats fed high-fat diet recovered impaired insulin responsiveness of skeletal muscles and muscle triglyceride concentrations. However, there was no direct stimulatory effect of leptin on insulin sensitivity of skeletal muscles in vitro.

Abdominal Fat↗
PubMed2005

New cold-adapted lipase from Photobacterium lipolyticum sp. nov. that is closely related to filamentous fungal lipases.

A Photobacterium strain, M37, showing lipolytic activity, was previously isolated from an intertidal flat of the Yellow Sea in Korea and identified as Photobacterium lipolyticum sp. nov. In the present study, the corresponding gene was cloned using the shotgun method. The amino acid sequence deduced from the nucleotide sequence (1,023 bp) corresponded to a protein of 340 amino acid residues with a molecular weight of 38,026. No sequence similarity was found with any known bacterial lipases/esterases; instead, the most similar enzymes were several filamentous fungal lipases. Although the similarity was very low (less than 16%), there were many conserved regions over the entire sequence and N-terminal oxyanion hole (RG) region, a signature sequence of filamentous fungal lipases. The novel protein M37 was produced in both a soluble and insoluble form when the Escherichia coli cells harboring the gene were cultured at 18 degrees C. The soluble protein exhibited lipase activity in a pH-stat assay using an olive oil emulsion. The M37 lipase also displayed a maximum activity at 25 degrees C and maintained its activity at a low temperature range (5-25 degrees C) with an activation energy (E(a)) of 2.07 kcal/mol. Accordingly, these results indicate that the M37 lipase from P. lipolyticum sp. nov. is a new cold-adapted enzyme.

Amino Acid Sequence↗
PubMed2005

Effect of PK11195, a peripheral benzodiazepine receptor agonist, on insulinoma cell death and insulin secretion.

Functional role of peripheral benzodiazepine receptor on mitochondrial membrane in apoptosis and insulin secretion from insulinoma cells was studied. A prototypic peripheral benzodiazepine receptor agonist PK11195 induced insulinoma cell apoptosis, while a central benzodiazepine receptor agonist did not. Death of insulinoma cells by PK11195 was inhibited by cyclosporin A, a blocker of mitochondrial permeability transition pore. Caspase inhibitors further inhibited MIN6N8 cell death. PK11195 induced dissipation of mitochondrial potential and cytochrome c translocation to cytoplasm. PK11195 induced an increase in cytoplasmic [Ca(2+)], which was reversed by cyclosporin A. Rhod-2 staining showed decreased mitochondrial [Ca(2+)] after PK11195 treatment. PK11195 potentiated glucose-induced insulin secretion probably due to the increased cytoplasmic [Ca(2+)]. Calpain was activated following Ca(2+) release, and calpain inhibitors attenuated death of insulinoma cells by PK11195. These results suggest that PK11195 induces mitochondrial potential loss, cytochrome c translocation, increased insulin secretion in conjunction with an increase in cytoplasmic [Ca(2+)] and calpain activation, which collectively leads to apoptosis of insulinoma cells.

Animals↗
PubMed2005

Morphometric studies on the testis of Korean ring-necked pheasant (Phasianus colchicus karpowi) during the breeding and non-breeding seasons.

The purpose of this study was to obtain detailed quantitative information on all cell types in the testis interstitium of Korean ring-necked pheasants and to combine these data with changes in the steroidogenic function of the testis during the breeding and non-breeding seasons. For animals collected during the breeding season, their testis weights, sperm production, serum testosterone levels and leuteinizing hormone (LH)-stimulated testosterone secretion were significantly (p < 0.01) increased compared to the non-breeding season. Testes of the pheasants during the non-breeding season displayed a 98% reduction in testis volume that was associated with a decrease in the absolute volume of seminiferous tubules (98% reduction), tubular lumen (100%), interstitium (90%), blood vessels (84%), lymphatic spaces (97%), Leydig cells (79%), mesenchymal cells (51%) and myoid cells (61%) compared to the breeding season. The numbers of Leydig cells, mesenchymal cells and myoid cells per testis in the breeding season were much higher than in the non-breeding season. Although the mean volume of a Leydig cell was 74% lower in the non-breeding season, the mean volumes of myoid and mesenchymal cells remained unchanged. These results demonstrate that there are striking differences in the testicular structure of the Korean ring-necked pheasant during the breeding and non-breeding seasons. Every structural parameter of the Leydig cell was positively correlated with both testosterone serum levels and LH-stimulated testosterone secretion. The correlation of changes in hormonal status with the morphometric alterations of Leydig cells suggests that the Korean-ring necked pheasant may be used as a model to study structure-function relationships in the avian testis.

Animals↗
PubMed2005

Awake nasotracheal intubation using fiberoptic bronchoscope in a pediatric patient with Freeman-Sheldon syndrome.

The Freeman-Sheldon syndrome is a congenital disease primarily affecting the facial, limb and respiratory muscles that give rise to classical clinical features including typical whistling face and short webbed neck associated with difficult intubation. We present successful awake nasotracheal intubation in a 6-year-old patient with typical clinical features of Freeman-Sheldon syndrome by using fiberoptic bronchoscope on two separate occasions.

Bronchoscopes↗
PubMed2005

The effects of apigenin-7-O-beta-D-glucuronopyranoside on reflux oesophagitis and gastritis in rats.

1. This study evaluated the inhibitory action of apigenin-7-O-beta-D-glucuronopyranoside (AGC), apigenin, and omeprazole on reflux oesophagitis and gastritis in rats. AGC was isolated from Clerodendron trichotomum leaves. 2. Oesophagitis and gastritis were induced by surgical procedure and the administration of indomethacin, respectively. The intraduodenal (i.d.) administration of AGC decreased the volume of gastric juice and increased the gastric pH compared with apigenin and omeprazole. The acid output was more inhibited by AGC in a dose-dependent manner than by apigenin and omeprazole. Compared with apigenin and omeprazole, AGC significantly decreased the size of gastric lesions, which were induced by exposure of the gastric mucosa to indomethacin. 3. Malondialdehyde (MDA) content, which is the end product of lipid peroxidation, was increased significantly after the induction of reflux oesophagitis. The MDA content was decreased by AGC (i.d. 3 mg kg(-1)), but not by either apigenin or omeprazole. This suggests that AGC has an antioxidative effect. In the oesophagitis group, the mucosal levels of glutathione (GSH) were significantly lower than that in the normal group. However, the GSH levels were preserved after administering the AGC, suggesting that AGC possesses scavenging activity. 4. In summary, AGC is more potent than apigenin and omeprazole at inhibiting reflux oesophagitis and gastritis and may therefore be a promising drug for their treatment.

Animals↗
PubMed2005

The effects of pulsatile versus non-pulsatile extracorporeal circulation on the pattern of coronary artery blood flow during cardiac arrest.

BACKGROUND: In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile versus non-pulsatile circulation to coronary artery flow and myocardial preservation in a cardiac arrest condition. METHODS: A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing 25-35 kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extracorporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the systemic arterial and coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of <0.05. RESULTS: The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p<0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p<0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p<0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the systemic and coronary sinus blood (p=NS). CONCLUSION: In the cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

Animals↗
PubMed2004

Mesenchymal progenitor cells in the human umbilical cord.

Mesenchymal progenitor or stem cells (MPCs) isolated from fetal blood, liver, and bone marrow are a population of multipotential cells that can proliferate and differentiate into multiple mesodermal tissues including bone, cartilage, muscle, ligament, tendon, fat, and stroma. The objective of this study was to isolate and characterize MPCs in the human umbilical cord. The suspensions of endothelial and subendothelial cells in cord vein were collected and cultured in M199 supplemented with 10% fetal bovine serum (FBS). Of 50 umbilical cord samples, 3 had numerous fibroblastoid cells morphologically distinguishable from endothelial cells. Fibroblastic cells displayed lack of expression of vWF, Flk-1, and PECAM-1, indicating the endothelial cell-specific marker. To investigate the differentiation potentials, the cells were cultured in adipogenic or osteogenic medium for 2 weeks. Fibroblast-like cells treated with adipogenic supplementation showed Oil red O-positive staining and expressed adipsin, FABP4, LPL, and PPARgamma2 genes by reverse transcriptase polymerase chain reaction (RT-PCR). In osteogenic differentiation, alkaline phosphatase activity and calcium accumulation were detected. RT-PCR studies determined that Cx43, osteopontin, and Runx2 genes were expressed in the osteogenic cultures. Among three cell lines cultured continuously for passage 10, two had normal karyotypes; however, one retained a karyotype of mos 46,XY[19]/47,XY,+mar[3]. These observations suggest that MPCs are present in human umbilical cord and possess several typical traits of MPCs.

Adipocytes↗
PubMed2004

Validation of the Korean version of the EORTC QLQ-C30.

This study evaluated the Korean version of the EORTC QLQ-C30 (version 3.0) in terms of psychometric properties and its validation. One hundred and seventy patients completed three questionnaires EORTC QLQ-C30, the Beck depression inventory (BDI), and a brief pain inventory (BPI). Multitrait scaling analyses demonstrated that all scales met multidimensional conceptualization criteria, in terms of convergence and discrimination validity. Cronbach's alpha coefficients for eight multiple-item scales were greater than 0.70, with the exception of cognitive functioning. All interscale correlations were statistically significant in the expected direction (p < 0.01). Multivariate analyses showed that physical and emotional functioning were significant explanatory variables for the global quality-of-life (QOL) scale (regression coefficients: 0.36, p < 0.001; and 0.37, p < 0.001; respectively). All scales were significantly associated with pain severity and interference of the BPI, and with the cognitive-affective and somatic scales of the BDI. The emotional-functioning scale was substantially correlated with the cognitive-affective scale and somatic scale of the BDI. These results demonstrate that the Korean version of the EORTC QLQ-C30 is a valid instrument for evaluating Korean-speaking patients with cancer, and can be used to distinguish clearly between subgroups of patients of differing performance status.

Adult↗
PubMed2004

The combination of zinc compounds and acidic pH limits aerobic growth of a Salmonella typhimurium poultry marker strain in rich and minimal media.

The objective of the present study was to examine the combined effects of zinc compounds with different acidic pH levels on the aerobic growth of a S. typhimurium poultry isolate in either rich or minimal media. When overall main effects of pH levels of medium or concentrations of Zn compounds were compared, growth rates of the S. typhimurium poultry isolate were significantly (p < 0.05) decreased by stepwise increase of pH levels of medium (pH 4, 5, 6, and 7) or concentrations (0.67, 3.35, and 6.03%) of Zn compounds (Zn acetate and Zn sulfate). In general growth rates of S. typhimurium poultry isolate appeared to be more reduced by Zn acetate than by Zn sulfate and more reduced in minimal media compared to rich media.

Animals↗
PubMed2004

Effects of high zinc diets using zinc propionate on molt induction, organs, and postmolt egg production and quality in laying hens.

This study was conducted to determine the ability of an alternative salt form of 1% Zn, Zn propionate, to induce molt in 66-wk-old hens. The hens were randomly assigned to 4 treatment groups of 27 or 28 birds each: a) molted conventionally by feed withdrawal, b) 1% Zn as Zn acetate, c) 1% Zn as Zn propionate, or d) nonmolted control for 9 d. Feed intake was (P < 0.05) depressed in Zn acetate and Zn propionate hens when compared with nonmolted control hens during the 9 d. Ovary weights of hens undergoing feed withdrawal, Zn acetate, or Zn propionate were not (P > 0.05) different from each other, but all were (P < 0.05) lighter than the ovary weights of nonmolted control hens. Zinc concentrations in the kidney and liver were (P < 0.05) increased in Zn acetate and Zn propionate molted hens when compared with nonmolted hens on the control diet or hens molted by feed withdrawal. Bone ash values were (P < 0.05) increased for Zn acetate and Zn propionate molted hens or nonmolted control hens as compared with molted hens on feed withdrawal. Over the entire 3-mo postmolt period, there were no significant differences in interior egg qualities, but egg weights from hens fed Zn propionate were (P < 0.05) heavier than those from hens on feed withdrawal. The data of the current study demonstrated that feeding a Zn propionate (1% zinc)-supplemented diet can induce molt.

Animal Feed↗
PubMed2004

Comparison of zinc acetate and propionate addition on gastrointestinal tract fermentation and susceptibility of laying hens to Salmonella enteritidis during forced molt.

Feed deprivation is the most common method used to induce molting and stimulate multiple egg-laying cycles in laying hens for commercial egg production. Unfortunately, an increased risk of Salmonella enteritidis (SE) colonization may result from the use of this method. Methods to stimulate multiple egg-laying cycles without increasing the risk of SE are needed. In each of 3 experiments, hens over 50 wk of age were divided into groups of 12 and placed in individual laying cages. One week before dietary changes, hens were put on an 8L:16D photoperiod that continued for the 9-d experimental period. Hens in all treatments were challenged orally with 10(4) cfu of SE on the fourth day. Treatments were full fed hens (nonmolted, NM), nonfed hens (molted, M), a zinc acetate diet (ZAC), and a zinc propionate diet (ZPR). The zinc diets contained 10,000 mg of zinc per kilogram of diet. Body weight losses were significantly higher in the M, ZPR, and ZAC treatments than in the NM treatment. Crop lactic acid decreased more in M, ZPR, and ZAC treatments than in NM hens in trial 2. Crop pH was significantly (P < 0.05) lower in NM hens than in M, ZAC, and ZPR hens in trial 2. Although cecal individual or total volatile fatty acids (VFA), and lactic acid were not significantly (P > 0.05) different between NM hens and M, ZAC and ZPR hens in trial 1, lactic acid was significantly (P < 0.05) higher in NM hens than in M, ZAC and ZPR hens (trial 2), and cecal total VFA were lower in M hens than in NM, ZAC and ZPR hens (trial 3). Colonization of SE in the crop and ceca was higher in the M and ZPR hens (trials 1 and 2). Liver, spleen, or ovary invasion by SE was higher in the M and ZPR hens (trials 1 and 2) than in NM hens. At the zinc concentration used in these studies, the zinc dietary regimens may be effective for reducing the risk of SE during induced molt.

Animals↗
PubMed2004

Anaesthesia in patients with Brugada syndrome.

Brugada syndrome is characterized by right bundle branch block, ST segment elevation in the precordial leads and sudden death caused by ventricular fibrillation. We present two successful anaesthetic management cases in patients with Brugada syndrome.

Adult↗