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Search Results: 1 - 10 of 10125 matches for " Jong Park "
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Retinoid and Ethanol-Sensitive Benzo(α)Pyrene Induction of Cytochrome P450 in Human Keratinocytes  [PDF]
John J. Wille, Jong Y. Park
Journal of Cancer Therapy (JCT) , 2012, DOI: 10.4236/jct.2012.36141
Abstract: Polycyclic aromatic hydrocarbons (PAHs) induce cytochrome P-450 monoxygenase enzymes that catalyze the formation of DNA adducts. We investigated the effects benzo(α)pyrene (B[α]P) alone or in combination with ethanol on normal human keratinocyte (NHK) growth, induction of cytochrome P-4501A1 (CYP1A1), and modulation of these treatments by retinoic acid (RA) in a serum-free culture medium. Growth-arrested confluent NHK serum-free cultures were treated with B[α]P alone or in combination with ethanol and RA. The effects on CYP1A1 enzyme activity were investigated. B[α]P treatment alone was not toxic to post-confluent cells; sub-toxic ethanol stimulated cell growth regardless B[α]P treatment. No CYP1A1 activity was detected in control or ethanol-treated NHK cell cultures. B[α]P alone induced CYP1A1 activity, and B[α]P plus ethanol treatment further enhanced B[α]P-induced CYP1A1 activity. Pretreatment with all-trans-RA (t-RA) abolished ethanol enhancement of CYP1A1 activity. There is a synergistic action of ethanol in combination with PAH on induction of P-450 cytochrome enzymes. By contrast, RA reverses ethanol enhancement implying a role for retinoid therapy in counteracting the risk posed by combined alcohol and PAH exposure on epidermal cell carcinogenesis.
Cell Cycle Arrest Mediates Global DNA Methylation Patterns in Normal Human Keratinocytes, Epidermoid Carcinoma Cells and Murine Embryonic Fibroblasts  [PDF]
John J. Wille, Jong Y. Park
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.41030
Abstract:

The 5-methylationcytosine (5-MC) DNA content of murine embryonic fibroblasts arrested in G1 by four growth conditions (Gc, Gn, Gd, and Gs) were hypermethylated relative to rapidly growing (RG) fibroblasts. Normal human keratinocytes (NHK) arrested in G1 by suspension were hypermethylated relative to RG cultures. Four RG cultures of epidermoid carcinoma cells (ECC) were hypomethylated relative to RG NHK cultures, and two cultures (SCC25 and A431) were further hypomethylated by SUS-induced arrest. Linear regression analyses established a positive linear correlation between growth rate and 5-MC content for three murine fibroblasts lines, and a negative correlation for both NHK and ECC lines.

Effects of Okadaic Acid, Retinoic Acid, and Phorbol Myristate Acetate Tumor Promoter on Oncogene Expression  [PDF]
John J. Wille, Jong Y. Park
Journal of Cancer Therapy (JCT) , 2014, DOI: 10.4236/jct.2014.56068
Abstract:

The effect of okadaic acid (OA) on proto-oncogene protein expression of c-neu, c-myc, v-rasH, EGFR, and phosphotyrosine-containing phosphoproteins (P-Tyr) was investigated in rapidly growing (RG) normal human keratinocytes (NHK) and in SV-40 virally-transformed keratinocytes (SVK) cultured in a growth factor supplemented serum-free medium as assessed by indirect immunofluorescence microscopy. P-Tyr positively stains cell surface antigens (cytoplasm) diffusely at monopolar sites in RG NHK cultures. OA-treatment intensifies cytoplasmic P-Tyr staining at localized monopolar intercellular focal adhesion (IFA) sites with reduced cytoplasmic staining. P-Tyr expression was predominate at IFA sites with little cytoplasmic staining in RG SVK cultures. OA-treatment increased monopolar P-Tyr staining and cytoplasmic staining. OA-treatment in RG NHK cultures intensified cytoplasmic staining of c-myc and EGFR (epidermal growth factor receptor) expression. OA-treatment in RG NHK and SVK cultures intensified c-neu staining at monopolar IFA sites and intensified c-neu staining at both cytoplasmic and bipolar IFA sites in RG SVK cells. OA was especially cytotoxic for SVK cells. RA treatment decreased c-neu expression in RG NHK cultures while TPA treatment has a lesser effect on both cytoplasmic and IFA sites. RA treatment also decreased P-Tyr staining in both NHK and SVK cells. Again, TPA had a lesser inhibitory effect on P-Tyr staining pattern. RA-treatment had a similar effect on P-Tyr staining of RG cultures of a mouse fibroblast cell line. These results confirm the generality of OA, RA and TPA on the regulation of oncogene expression in both normal and malignantly transformed keratinocytes.

Induced Differentiation of Epithelioid Carcinoma Cell Lines: Evidence for Tumor Cell Quantal Mitosis  [PDF]
John J. Wille, Jong Y. Park
Journal of Cancer Therapy (JCT) , 2016, DOI: 10.4236/jct.2016.711080
Abstract: The effects of growth factors and calcium concentrations present in different culture media on induction of terminal differentiation were investigated for four different epidermoid carcinoma cell lines, Hela, KB, A431, and SCC-25, and their responses determined relative to those elicited by normal human keratinocytes subjected to these culture conditions. Differentiation status was determined cyto-chemically by a validated keratin protein staining method, and by autoradiographic analyses. Growth and differentiation promoting factors that influenced the direction of integrated control of growth and differentiation in normal human keratinocytes were found to be effective for some cell lines but not others. The factors examined were 1) high density arrest in serum-free and serum-containing media, 2) media shifts from high density culture in serum-containing media to low density growth factor-depleted or supplemented serum-free medium, and 3) the concentration of calcium in the media. The extent and degree of differentiation achieved varied among different cell lines depend on the presence or absence of serum, EGF and insulin protein growth factors. Certain growth media appear to sponsor keratin protein, cyto-chemically-detected differentiation, and evidence of quantal mitotic division in low density HeLa cell and SCC25 cell cultures. Epidermoid carcinoma cell lines retain limited capacity to commit to early stages of cell differentiation.
A Ground-Beetle, Chlaenius hamifer Chaudoir, New to Korea (Coleoptera: Carabidae)
Jong Kyun Park,Jinyoung Park
Animal Systematics, Evolution and Diversity , 2013, DOI: http://dx.doi.org/10.5635/ased.2013.29.2.188
Abstract: Chlaenius is a large and diverse genus of ground beetle. This colorful beetle recognized from its pubescent elytra and pungent defensive secretions. Subgenus Pachydinodes belonging to the genus Chlaenius were reported eight species from Palaearctic, among them four species, Chlaenius (Pachydinodes) abstersus Bates, C. (P.) pictus Chaudoir, C. (P.) tetragonoderus Chaudoir, C. (P.) virgulifer Chaudoir were reported in Korea up to now. In here, Chlaenius hamifer Chaudoir are report firstly in Korea. Description and photo of adult and aedeagus are provided.
Stability of the Cauchy-Jensen Functional Equation in C ¢ —-Algebras: A Fixed Point Approach
Choonkil Park,Jong Su An
Fixed Point Theory and Applications , 2008, DOI: 10.1155/2008/872190
Abstract: we prove the Hyers-Ulam-Rassias stability of C ¢ —-algebra homomorphisms and of generalized derivations on C ¢ —-algebras for the following Cauchy-Jensen functional equation 2f((x+y)/2+z)=f(x)+f(y)+2f(z), which was introduced and investigated by Baak (2006). The concept of Hyers-Ulam-Rassias stability originated from the stability theorem of Th. M. Rassias that appeared in (1978).
Quantifier Scope and Constituency
Jong C. Park
Computer Science , 1995,
Abstract: Traditional approaches to quantifier scope typically need stipulation to exclude readings that are unavailable to human understanders. This paper shows that quantifier scope phenomena can be precisely characterized by a semantic representation constrained by surface constituency, if the distinction between referential and quantificational NPs is properly observed. A CCG implementation is described and compared to other approaches.
Asymptotic behavior of almost-orbits of reversible semigroups of non-Lipschitzian mappings in Banach spaces
Jong Soo Jung,Jong Yeoul Park,Jong Seo Park
International Journal of Mathematics and Mathematical Sciences , 1997, DOI: 10.1155/s0161171297000094
Abstract: Let C be a nonempty closed convex subset of a uniformly convex Banach space E with a Fr chet differentiable norm, G a right reversible semitopological semigroup, and ° ’ ={S(t):t ¢ G} a continuous representation of G as mappings of asymptotically nonexpansive type of C into itself. The weak convergence of an almost-orbit {u(t):t ¢ G} of ° ’ ={S(t):t ¢ G} on C is established. Furthermore, it is shown that if P is the metric projection of E onto set F(S) of all common fixed points of ° ’ ={S(t):t ¢ G}, then the strong limit of the net {Pu(t):t ¢ G} exists.
Storing and Searching Metadata for Digital Broadcasting on Set-Top Box Environments  [PDF]
Jong-Hyun Park, Ji-Hoon Kang
Journal of Software Engineering and Applications (JSEA) , 2008, DOI: 10.4236/jsea.2008.11005
Abstract: Digital broadcasting is a novel paradigm for the next generation broadcasting. Its goal is to provide not only better quality of pictures but also a variety of services that is impossible in traditional airwaves broadcasting. One of the important factors for this new broadcasting environment is the interoperability among broadcasting applications since the environment is distributed. Therefore the broadcasting metadata becomes increasingly important and one of the metadata standards for a digital broadcasting is TV-Anytime metadata. TV-Anytime metadata is defined using XML schema, so its instances are XML data. In order to fulfill interoperability, a standard query language is also required and XQuery is a natural choice. There are some researches for dealing with broadcasting metadata. In our previous study, we have proposed the method for efficiently managing the broadcasting metadata in a service provider. However, the environment of a Set-Top Box for digital broadcasting is limited such as low-cost and low-setting. Therefore there are some considerations to apply general approaches for managing the metadata into the Set-Top Box. This paper proposes a method for efficiently managing the broadcasting metadata based on the Set-Top Box and a prototype of metadata management system for evaluating our method. Our system consists of a storage engine to store the metadata and an XQuery engine to search the stored metadata and uses special index for storing and searching. Our two engines are designed independently with hardware platform therefore these engines can be used in any low-cost applications to manage broadcasting metadata.
Cancer Chemopreventive Retinoids: Validation and Analysis of in Vivo and in Vitro Bioassay Results  [PDF]
John J. Wille, Jong Y. Park, Y. Fulmer Shealy
Journal of Cancer Therapy (JCT) , 2016, DOI: 10.4236/jct.2016.713098
Abstract: Several natural and synthetic retinoids (vitamin-A derived analogies) were examined for their potential anti-cancer activity in both in vivo animal models and a novel in vitro human keratinocyte clonal growth bioassay system. The natural retinoids included all-trans-retinoic (RA), 13-cis-retinoic acid, 4-oxoretinoic acid, and retinol. Among the synthetic retinoids tested were all trans N-(4-hydroxy(phenyl)retinamide, 3-substituted oxoretinoic acids, and 13 cis-N-ethylretinamide. The animal models employed were: 1) vitamin A-deficient hamster tracheal organ assay (HTOC); 2) the benzo(α)pyrene-induced squamous metaplasia in a hamster tracheal organ system (BP-HTOC); 3) the mouse skin tumor promoter (TPA)-induced ornithine decarboxylase enzyme assay(ODC); 4) the mouse skin papilloma (MPA) assay; and 5) a novel retinoid bioassay in which retinoids display IC50 values to inhibit clonal growth of NHK. All-trans-RA, 4-oxoretinoic acid and retinol were consistently more active than any of the synthetic derivatives in all bioassays tested. A statistical model was developed and significant positive correlations were found between: 1) ED50 values in the HTOC system and reduction in TPA-induced ODC enzyme activity; 2) tumors per animal in the MPA bioassay and suppression of TPA-induced ODC activity; and 3) a positive correlation between suppression of tumors per animal in the MPA assay, and retinoid inhibition of keratinocyte clonal growth. Test retinoids, were tested for their capacity to inhibit the clonal growth of a squamous carcinoma cell line (SCC-25), which were found to be 2
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