Biomedical subjects

Y S Song

Publications and source records attributed to Y S Song.

At least 19 recordsLinked to original sources

PubMed2005

An efficient cryopreservation procedure for potato (Solanum tuberosum L.) utilizing the new ice blocking agent, Supercool X1000.

Cryopreservation has been recognized as a practical and efficient tool for long-term storage of vegetatively propagated plants. This study was conducted to investigate effects of modified vitrification techniques on cryopreservation of potato. In vitro plants of potato cultivars "Superior" and "Atlantic" were cold acclimated, and axillary buds were precultured, osmoprotected, exposed to PVS-2 solution, plunged into liquid nitrogen, thawed, and finally planted in the regeneration medium. In the modified vitrification technique an ice-blocking agent, Supercool X1000, was added with PVS-2 solution. Cold acclimation affected survival of cryopreserved shoot tips, and the highest survival (46.7%) was obtained after 3 weeks of acclimation at 10 degrees C. Shoot tips exposed to 2M glycerol plus 0.6M sucrose for 40 min gave 51.5% and 11.7% survival in "Atlantic" and "Superior" at 10 degrees C, respectively. Cold acclimated and osmoprotected shoot tips were dehydrated with PVS-2 containing different concentrations of Supercool X1000 prior to a plunge into liquid nitrogen. Treatments with 0.1% and 1% of Supercool X1000 significantly improved survival by 55% in "Superior" and 71.3% in "Atlantic", respectively. After cryopreservation, vitrified shoot tips resumed growth within a week in a medium (1 mg l(-1) GA(3), 0.5 mg l(-1) zeatin, and 0.1 mg l(-1) IAA) with a low level of Pluronic F-68 (0.005%) and survival was 33.7% higher in "Atlantic" and 14.7% higher in "Superior" than the control (without Pluronic F-68).

Cryopreservation↗

PubMed2005

Phospho-ser 15-p53 translocates into mitochondria and interacts with Bcl-2 and Bcl-xL in eugenol-induced apoptosis.

Our previous studies demonstrated that antiallergic effects of herbs such as clove and Magnoliae Flos (MF) resulted from the induction of apoptosis in mast cells. We here examined whether the antiallergic activity was caused by eugenol (4-allyl-2-methoxyphenol) which was one of major ingredients in the essential oils or extracts of numerous plants including clove and Magnoliae Flos. RBL-2H3 cells were treated with eugenol, and DNA electrophoresis, Western blotting, immunocytochemistry, confocal microscopy and immunoprecipitation were conducted. Effect of eugenol was tested using a rat anaphylaxis model. RBL-2H3 cells treated with eugenol showed typical apoptotic manifestations and translocation of p53 into mitochondria. Antisense p53 partially prevented the induction of apoptosis. Noticeably, we observed that p53 translocated into mitochondria was phosphorylated on ser 15. Phospho-ser 15-p53 physically interacted with Bcl-2 and Bcl-xL in mitochondria and its translocation into mitochondria preceded cytochrome c release and mitochondrial membrane potential (MMP) reduction. We also depicted that the survival of animals even after administration of the fatal dose of compound 48/80 might result from the decreased number of mast cells by eugenol pretreatment. In conclusion, eugenol induces apoptosis in mast cells via translocation of phospho-ser 15-p53 into mitochondria.

Animals↗

PubMed2004

Food technology: challenge for health promotion.

The food technology has brought countless benefits to today's food supply. Despite its many positive contributions, it has also brought unintended negative consequences. It is the time to mobilize the food technology to help the food supply more secure, safer and healthier, and here three possible approaches are foreseeable: First, we should continue to improve the conventional technologies. Many wholesome foods have been prepared and preserved using natural materials simply by fermentation. Second, we have to enhance the minimal processing as much as applicable. Third, new ingredients, intelligent packaging and functional foods should be explored to improve food supply and health. Today, consumer interest in the functional foods has been increased tremendously, and the future of food lies in the functional foods. However, the situations in the developing world are different from this. As food resource is limited in this region, food technology has to be emphasized to increase food supply. To help solve such complex problems, not only new technologies, but also conventional technologies have to be mobilized. Simultaneously, even higher technical capabilities have to be built up by applying new findings from the related disciplines to allow the food technology to play its vital role.

Food Handling↗

PubMed2004

Involvement of bone marrow-derived stem and progenitor cells in the pathogenesis of pterygium.

AIMS: To evaluate the involvement of multipotential stem and progenitor cells in the pathogenesis of pterygium. METHODS: Paraffin-embedded and snap-frozen primary pterygium (n = 10) were serially sectioned and analysed immunohistochemically to determine the expression level of AC133 (marker for the primitive haematopoietic progenitors), CD34 (marker for the haematopoietic progenitor cells and endothelium), c-Kit (marker for haematopoietic and stromal progenitor cells), and STRO-1 (a differentiation antigen present on bone marrow fibroblast cells and on various nonhaematopoietic progenitor cells). RESULTS: In all the primary pterygium, immunoreactivity of AC133 and STRO-1 was found in some of the epithelial and stromal cells, CD34 was observed in the vascular endothelium, and some scattered ovoidal cells were found in the subepithelial connective tissue. C-Kit was expressed mainly in the basal epithelium of the head portions, and some spindle-shaped stromal cells. There is no immunoreactivity of AC133, c-Kit, and STRO-1 in normal conjunctiva, whereas CD34 was mildly stained with vessel wall. CONCLUSION: Multipotential stem and progenitor cells may be involved in the pathogenesis of pterygium through its differentiation into fibroblasts and vascular endothelial cells.

AC133 Antigen↗

PubMed2003

Daeganghwal-tang inhibits the stem cell factor-induced migration and inflammatory cytokines secretion in mast cells.

Traditional Oriental medicinal prescription, Daeganghwal-tang (DGHT) has been used for the treatment of rheumatoid arthritis (RA) in Korea. However, its effect in experimental models remains unknown. Recent reports suggest that in patients with RA, synovial mast cells increase in number and show signs of activation and inflammatory cytokines secretion. Our results show that stem cell factor (SCF) is a potent chemotactic factor for the mast cells in vitro. The chemotactic response to SCF was blocked by DGHT. When DGHT (1mg/ml) was added, the secretion of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6 was inhibited by 60.1, 81.8, 72.5%, respectively in phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187-stimulated HMC-1 cells. In addition, the expression of TNF-alpha mRNA in HMC-1 cells was inhibited by DGHT (1mg/ml). These findings indicate that DGHT inhibits SCF-induced migration and PMA plus calcium ionophore-stimulated inflammatory cytokines secretion in mast cells.

Animals↗

PubMed2003

The natural history of hydronephrosis after radical hysterectomy with no intraoperatively recognisable injury to the ureter: a prospective study.

OBJECTIVE: To investigate, in a prospective study, the natural history of hydronephrosis of the urinary tract after radical hysterectomy. PATIENTS AND METHODS: From December 1997 to March 2001, 34 patients with localized cervical cancer underwent radical hysterectomy by one gynaecologist, with no intraoperatively identifiable injury to the ureter. Intravenous urography was used routinely before and at 2 and 4 weeks after surgery. The degree of hydronephrosis was graded I-IV. RESULTS: Urography before surgery showed no abnormal finding in any of the patients, except in one with a unilateral duplex kidney. Hydronephrosis was found in 10 units in the upper tract (grade II in eight, III in one and IV in one) in seven patients (21%) 2 weeks after surgery (one right, three left and three bilateral). All the ureteric narrowing was in the distal ureter. The hydronephrosis disappeared in four units in three patients, but became worse in two units in two patients with bilateral pathology in the fourth week. At 3 months after surgery no hydronephrosis had deteriorated and the hydronephrosis in all units had disappeared by 6 months. The presence of hydronephrosis was significantly correlated with pathological stage and age (P < 0.05). CONCLUSION: Hydronephrosis was detected after radical hysterectomy even with no intraoperatively recognisable injury to the ureter, but in most the hydronephrosis improved spontaneously and needed no ureteric stenting or surgical intervention.

Adult↗

PubMed2003

Effectiveness of polypropylene film as a barrier to migration from recycled paperboard packaging to fatty and high-moisture food.

The capability of a polypropylene (PP) film barrier to prevent migration of residual contaminants from recycled paperboard into food simulants was studied. Anthracene, benzophenone, methyl stearate and pentachlorophenol were chosen as chemical surrogates to represent classes of contaminants likely to be found in recycled paper/paperboard. Each surrogate was spiked into a test specimen made of seven thin virgin paper layers at concentrations of 1-50 mg kg(-1). Test specimen were dried, stacked and sandwiched with PP films, laminated with PP film and then subjected to migration experiments using a compression cell maintained at 100 degrees C for 2 h. The concentration of the surrogates in the test specimen and in 95% ethanol, isopropanol and 10% ethanol food-simulating solvents was determined by gas chromatography with flame ionization and electron capture detection. The results show that although the concentrations of the surrogates in the food simulants decreased with an increase in PP film thickness, they were still high and generally resulted in dietary concentrations >0.5 microg kg(-1), the level that US Food and Drug Administration would equate with negligible risk for a contaminant migrating from food packaging. Only at the lowest spiking level (1 mg kg(-1) benzophenone) did migration from the paperboard through a 0.127-mm PP film result in a dietary concentration of </=0.5 microg kg(-1). Therefore, it can be concluded that for an extended time at 100 degrees C, PP would not be an acceptable barrier to migration of contaminants that are expected to be in post-consumer paper/paperboard.

Conservation of Natural Resources↗

PubMed2003

Migration of volatile degradation products into ozonated water from plastic packaging materials.

Migration of volatile degradation products from poly(ethylene terephthalate) (PET) and high-density polyethylene (HDPE) bottles, polypropylene (PP) caps and ethyl vinyl acetate (EVA) liners into ozonated water was measured. Polymer strips were immersed in deionized and distilled water with ozone concentrations of 0.5, 2.5 and/or 5 mg kg(-1) inside 35-ml vials, which were clamp-sealed and stored at 40 degrees C for 10 days. A purge-and-trap unit was developed to extract volatile products from the ozonated water in vials. The extractables were trapped in an adsorbent tube and analysed using a GC-MS coupled with an automated thermal desorber (ATD). Mass spectra were interpreted by comparison with a NIST mass spectral library, and an internal standard method was used to quantify the extractables of interest. Several volatile compounds found in ozonated water that had been in contact with PP, EVA and HDPE polymers included butanal, pentanal, hexanal, heptanal, octanal, nonanal, 2,2-dimethyl propanal, 3-hexanone, 2-hexanone and heptanone. These compounds could cause off-taste and off-odour with a low organoleptic threshold. In general, the concentrations of these volatile compounds increased with an increased exposure to ozone. The highest concentration found was 14.1 +/- 0.6 microg kg(-1) for hexanal with a 5 mg kg(-1) ozone treatment of PP caps. Even at a treatment level of 5 mg kg(-1) ozone, which is greater than 10 times the current regulatory limits for bottled water, the extractables migrating from those polymers were within the levels permitted by the FDA. For the PET sample, no significant peaks were observed before or after ozonation. These results imply that PP caps containing EVA liners may be major sources of off-odour and taste in ozonated bottled water.

Disinfection↗

PubMed2003

An efficient algorithm for statistical multiple alignment on arbitrary phylogenetic trees.

We present an efficient algorithm for statistical multiple alignment based on the TKF91 model of Thorne, Kishino, and Felsenstein (1991) on an arbitrary k-leaved phylogenetic tree. The existing algorithms use a hidden Markov model approach, which requires at least O( radical 5(k)) states and leads to a time complexity of O(5(k)L(k)), where L is the geometric mean sequence length. Using a combinatorial technique reminiscent of inclusion/exclusion, we are able to sum away the states, thus improving the time complexity to O(2(k)L(k)) and considerably reducing memory requirements. This makes statistical multiple alignment under the TKF91 model a definite practical possibility in the case of a phylogenetic tree with a modest number of leaves.

Algorithms↗

PubMed2002

Common and differential mechanisms of gonadotropin receptors.

The gonadotropin receptors are G-protein-coupled receptors with unique structural and functional features, consisting of two halves. The N-terminal extracellular half (exodomain) binds the hormones, whereas the C-terminal membrane-associated half (endodomain) is responsible for receptor activation. In this review, the novel ternary interactions, contact points and mutual modulations among the exodomain, endodomain and hormone for hormone binding and signal generation are described based on the latest observations. This discussion is contrary to the yiew that the exodomain and endodomain are independent, at least functionally, and provides new insights into the receptor mechanisms for the gonadotropins and other G-protein-coupled receptors.

Amino Acid Sequence↗

PubMed2001

Two photon absorption properties of 1,3,5-tricyano-2,4,6-tris(styryl)benzene derivatives.

Two-photon absorption (TPA) properties of 1,3,5-tricyano-2,4,6-tris(styryl)benzene derivatives have been investigated. Comparison of the absorption and fluorescence spectra reveals that these compounds show large Stokes shifts, which increase gradually as the conjugation length increases. One-photon absorption and excitation spectra are similar except that the latter exhibit several peaks near lambda(max). It is also found that the one- and two-photon-induced fluorescence excitation spectra are quite similar, which indicates that the one- and two-photon allowed-excited states are the same. The peak TPA cross section values (delta(max)) measured with nanosecond pulses by the two-photon-induced fluorescence method are in the range (50-2620) x 10(-50) cm4 s/photon. The delta(max) value increases as the donor strength and conjugation length increase. A linear relationship is observed between delta(max) and beta, and this delta-beta relationship is found to serve as a useful synthetic strategy for the design of novel TPA dyes with the octupolar structure.

Journal Article↗

PubMed2001

Promoted expression of mast cell-specific proteases in IgE-dependent passive cutaneous anaphylaxis responses.

BACKGROUND: Various factors can influence the protease expression phenotype of mast cells. METHODS: In an effort to understand the potential role of the mast cell proteases in the IgE-dependent passive cutaneous anaphylaxis (PCA) responses of murine tissues, we studied the changes of proteases expression. The expressions of proteases were examined by Northern blotting and immunohistochemistry. RESULTS: Promoted expression phenotypes of mouse mast cell protease (mMCP)-4, and rat mast cell protease I were accompanied by initiation of anti-dinitrophenyl (DNP) IgE-induced PCA responses, suggesting that the induction of these proteases expression are associated with IgE-mediated anaphylaxis responses. Elevated level of the L-histidine decarboxylase (HDC) mRNA expression was also observed in the PCA tissues and the activated mast cells, compared with that of the corresponding control tissue and cells, due to the activation of mast cells. CONCLUSIONS: Promoted protease expression phenotype appears to be linked with the induction of HDC expression.

Animals↗

PubMed2001

Antiplatelet mechanism of 2-chloro-3-(4-hexylphenyl)-amino-1,4-naphthoquinone (NQ304), an antithrombotic agent.

The effects of 2-chloro-3-(4-hexylphenyl)-amino-1,4-naphthoquinone (NQ304), an antithrombotic agent, on aggregation, binding of fibrinogen to glycoprotein IIb/IIIa and intracellular signals were investigated using human platelets. NQ304 inhibited thrombin-, arachidonic acid- and thapsigargin-induced aggregation of washed human platelets with the IC50 values of 22.2+/-0.7, 6.5+/-0.2, and 7.6+/-0.1 microM, respectively. NQ304 significantly inhibited fluorescein isothiocyanate-conjugated fibrinogen binding to human platelet surface glycoprotein IIb/IIIa receptor by 75%, but failed to inhibit the fibrinogen binding to purified glycoprotein IIb/IIIa receptor. This result suggests that NQ304 inhibit platelet aggregation by suppression of an intracellular pathway that involves exposure of the glycoprotein IIb/IIIa receptor, rather than by direct inhibition of fibrinogen-glycoprotein IIb/IIIa binding. NQ304 significantly inhibited thrombin-induced increase in intracellular Ca2+ mobilization at the dose of 30 microM and ATP secretion in a dose-dependent manner. It also inhibited thrombin- and arachidonic acid-induced thromboxane A2 formation in human platelet dose-dependently. In conclusion, the antiplatelet mechanism of NQ304 may be due to the reduction of the thromboxane A2 formation, inhibition of adenosine triphosphate release and intracellular calcium mobilization.

Adenosine Triphosphate↗

PubMed2001

Is there a role of radial rigidity in the evaluation of erectile dysfunction?

RigiScan has been the most widely utilized device for measuring erectile rigidity. However, the use of the RigiScan in the evaluation of erectile dysfunction has questionable because the RigiScan device does not directly determine axial rigidity. The aim of this study is to clarify that radial rigidity measured by RigiScan reflects the intracorporeal pressure and erectile capability efficiently. From January 1998 to May 1999, a total of 23 patients with erectile dysfunction were involved in the study. They were evaluated by RigiScan and duplex ultrasonography after intracorporeal injection of prostaglandin E1. We investigated the relationship between radial rigidity and the resistance index. The results of radial rigidity were also compared with that of the degree of erection. For the entire group, significant correlations were found between radial rigidity and the resistance index (r=0.680, P<0.001 for tip rigidity; r=0.703, P<0.001 for base rigidity). In addition, for 12 patients whose tip rigidity exceeded 60% and for 10 whose base rigidity exceeded 60%, the correlations between radial rigidity and the resistance index remained (r=0.659, P=0.020 for tip rigidity; r=0.759, P=0.011 for base rigidity). Based on the response determined by patients, radial rigidity represented the degree of erection efficiently. Our findings suggest that RigiScan is a useful diagnostic tool. Radial rigidity represents the intracorporeal pressure efficiently and has an acceptable role in the evaluation of erectile dysfunction.

Adult↗

PubMed2001

Polymorphism of TP53 codon 72 and the risk of cervical cancer among Korean women.

OBJECTIVE: It has recently been suggested that white women who are homozygous for the allele of the gene for wild-type p53 protein (TP53) that encodes arginine at position 72 are more susceptible to human papillomavirus-associated cervical carcinoma than are women who are heterozygous for this polymorphism and women who are homozygous for the allele that encodes proline at that position. This study was undertaken to analyze whether the TP53 codon 72 single-nucleotide polymorphism might be correlated with the risk of cervical cancer among Korean women. STUDY DESIGN: Peripheral blood samples from patients with invasive cervical carcinoma yielding a positive result for human papillomavirus 16 (n = 100), patients with cervical intraepithelial neoplasia grade III (n = 134), and healthy control subjects (n = 100) were examined. The presence and genotype of human papillomavirus in cancerous cervical tissues were determined by E6, E7-based nested polymerase chain reaction. Germline genomic deoxyribonucleic acid was extracted from peripheral blood leukocytes and examined by polymerase chain reaction amplification of the specific allele assay as described by Storey et al. Deoxyribonucleic acid samples from patients whose TP53 sequences had been determined by direct sequencing were used as positive control preparations. RESULTS: The respective proportions of individuals who are homozygous for the arginine allele, homozygous for the proline allele, and heterozygous for the 2 alleles were 40%, 12%, and 48% among women with invasive cervical carcinoma, 52%, 9%, and 39% among women with cervical intraepithelial neoplasia grade III, and 52%, 11%, and 37% among the control group. No significant differences in the frequency of codon 72 alleles were found among the 3 groups (chi(2) = 4.414; P =.353; degrees of freedom = 4). CONCLUSION: This finding suggests that the risk of cervical cancer may not be increased for Korean women with the allele of TP53 encoding arginine at codon 72.

Antibodies, Viral↗

PubMed2001

Phosphatidylinositol 3-kinase regulates proliferation of RAW 264.7 macrophages.

Phosphatidylinositol 3-kinase (P13-kinase) is an enzyme that acts as a direct biochemical link between a novel phosphatidylinositol pathway and a number of proteins containing intrinsic or associated kinase activities. Here we demonstrate that wortmannin, P13-kinase inhibitor, decreases the proliferation of RAW 264.7 macrophages and that another structurally unrelated inhibitor of P13-kinase, LY294002. also inhibits the proliferation. These results indicate a possible involvement of P13-kinase in RAW 264.7 macrophages growth regulation. Wortmannin stimulation of RAW 264.7 macrophages is followed by sustained expression of the mRNA of c-fos and a transient expression of the mRNA of c-jun. We also show that the wortmannin and LY294002 induce a cell cycle arrest in asynchronously growing cells leading to an inhibition of cell proliferation after 12 h of treatment. In addition, wortmannin or LY294002 inhibited the phorbol 12-myristate 13-acetate-induced macrophages proliferation potently. These results suggest that P13-kinase plays an important role in growth regulation of RAW 264.7 macrophages and that protein kinase C is a down stream effector of P13-kinase.

Androstadienes↗

PubMed2000

Determination of amphetamine and methamphetamine in serum via headspace derivatization solid-phase microextraction-gas chromatography-mass spectrometry.

This study evaluates solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) to determine trace levels of amphetamine and methamphetamine in serum. Headspace post-derivatization in a laboratory-made design with heptafluorobutyric anhydride vapor following SPME was compared with that without derivatization SPME. The SPME experimental procedures to extract amphetamine and methamphetamine in serum were optimized with a relatively non-polar poly(dimethylsiloxane) coated fiber at pH 9.5, extraction time for 40 min and desorption at 260 degrees C for 2 min. Experimental results indicate that the concentration of the serum matrix diluted to a quarter of original (1:3) ratio by using one volume of buffer solution of boric acid mixed with sodium hydroxide and two volumes of water improves the extraction efficiency. Headspace derivatization following SPME was performed by using 6 microl 20% (v/v) heptafluorobutyric anhydride ethyl acetate solution at an oil bath temperature of 270 degrees C for 10 s. The precision was below 7% for analysis for without derivatization and below 17% for headspace derivatization. Detection limits were obtained at the ng/l level, one order better obtained in headspace derivatization than those achieved without derivatization. The feasibility of applying the methods to determine amphetamine and methamphetamine in real samples was examined by analyzing serum samples from methamphetamine abused suspects. Concentrations of the amphetamine and methamphetamine ranged from 6.0 microg/l (amphetamine) to 77 microg/l (methamphetamine) in serum.

Amphetamines↗

PubMed2000

The role of the hinge region of the luteinizing hormone receptor in hormone interaction and signal generation.

Luteinizing hormone receptor, a G protein-coupled receptor, consists of two halves, the N-terminal extracellular hormone binding domain (exodomain) and the C-terminal membrane-associated, signal-generating domain (endodomain). The exodomain has seven to nine Leu-rich repeats, which are generally thought to form a 1/3 donut-like structure and interact with human choriogonadotropin (hCG). The resulting hCG-exodomain complex adjusts the structure and its association with the endodomain, which results in signal generation in the endodomain. It is unclear whether the rigid 1/3 donut structure could provide the agility and versatility of this dynamic action. In addition, there is no clue as to where the endodomain contact point (the signal modulator) in the exodomain is. To address these issues, the exodomain was examined by Ala scan and multiple substitutions, while receptor peptides were used for photoaffinity labeling and affinity cross-linking. Our results show that the C-flanking sequence (hinge region), Thr(250)-Gln(268), of the Leu-rich repeats (LRRs) specifically interacts with hCG, preferentially hCGalpha. This interaction is inhibited by exoloop 2 of the endodomain but not by exoloops 1 and 3, suggesting an intimate relationship between Thr(250)-Gln(268), exoloop 2, and hCG. Taken together, our observations in this article suggest a new paradigm that the LRRs contact the front of hCG, while both flanking regions of the LRRs interact with the sides of hCG. This would trap hCG in the 1/3 donut structure of the LRRs and enhance the binding affinity. In addition, mutations of conserved Ser(255) in the sequence can constitutively activate the receptor. This provides a clue for the signal modulator in the exodomain. In contrast, a phenyl or phenolic group is necessary at conserved Tyr(253) for targeting the receptor to the surface.

Amino Acid Motifs↗