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Search Results: 1 - 10 of 28183 matches for " Sin Hang Lee "
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Detection of human papillomavirus L1 gene DNA fragments in postmortem blood and spleen after Gardasil® vaccination—A case report  [PDF]
Sin Hang Lee
Advances in Bioscience and Biotechnology (ABB) , 2012, DOI: 10.4236/abb.2012.38148
Abstract: A same-nested PCR was used to re-amplify the amplicon of a hypervariable region of the HPV-16 L1 gene DNA in the postmortem blood and splenic tissue obtained at autopsy of a formerly healthy teenage girl who suffered a sudden unexpected death in sleep 6 months after 3 intramuscular injections of a quadrivalent HPV vaccine, Gardasil?. A full autopsy analysis revealed no cause of death. The HPV-16 gene DNA detected in the postmortem materials was similar to the HPV-16 gene DNA fragments in Gardasil? in that both were in non-B-conformation, requiring nondegenerate GP6 and MY11 primers to re-amplify the PCR amplicon for detection and to generate a template useful for direct DNA sequencing. A sequence excised from the base-calling DNA sequencing electropherogram was analyzed by Basic Local Alignment Search Tool (BLAST) alignment and a 45 - 60 base sequence fully matched with a standard hypervariable region of the HPV-16 L1 gene retrieved from the National Center for Biotechnology Information database validated the correct genotyping for HPV- 16 L1 gene DNA. These naked non-proliferating HPV- 16 L1 gene DNA fragments appeared to be in the macrophages of the postmortem blood and spleen, and were protected from degradation by binding firmly to the particulate aluminum adjuvant used in vaccine formulation. The significance of these HPV DNA fragments of a vaccine origin found in post-mortem materials is not clear and warrants further investigation.
Topological conformational changes of human papillomavirus (HPV) DNA bound to an insoluble aluminum salt—A study by low temperature PCR  [PDF]
Sin Hang Lee
Advances in Biological Chemistry (ABC) , 2013, DOI: 10.4236/abc.2013.31010
Abstract:

A low temperature (LoTemp?) polymerase chain reaction (PCR), conducted at cycling temperatures not to exceed 85and catalyzed by a novel highly processive HiFi? DNA polymerase with proofreading function, was used to study the topological conformational changes of the human papillomavirus (HPV) L1 gene DNA fragments bound to the insoluble amorphous aluminum hydroxyphosphate sulfate (AAHS) adjuvant in the quadrivalent HPV vaccine, Gardasil?. L1 gene DNA fragments of HPV-11, HPV-18 and HPV-16 were detected in the AAHS particles by nested PCR, but all were lacking a region that was amplifiable by an MY09 degenerate primer. In addition, a pair of degenerate consensus GP6/MY11 primers was able to amplify a target segment of the HPV-11 L1 gene DNA and the HPV-18 L1 gene DNA bound to the AAHS particles as expected for any HPV DNA in the B-conformation. However, there was no co-amplification of the HPV-16 L1 gene DNA known to coexist in the same samples. The lack of co-amplification was verified by direct DNA sequencing of the PCR amplicons. The companion HPV-16 L1 gene DNA in the same sample required repeated PCRs with a pair of modified non-degenerate GP6/ MY11 primers for detection. This melting profile of the HPV-16 L1 gene DNA was similar to that of the HPV-16 L1 gene DNA recently discovered in the postmortem blood of a young woman who suffered a sudden unexpected death 6 months

A Novel Low Temperature PCR Assured High-Fidelity DNA Amplification
Guofan Hong,Sin Hang Lee,Shichao Ge,Shaoxia Zhou
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms140612853
Abstract: As previously reported, a novel low temperature (LoTemp) polymerase chain reaction (PCR) catalyzed by a moderately heat-resistant (MHR) DNA polymerase with a chemical-assisted denaturation temperature set at 85 °C instead of the conventional 94–96 °C can achieve high-fidelity DNA amplification of a target DNA, even after up to 120 PCR thermal cycles. Furthermore, such accurate amplification is not achievable with conventional PCR. Now, using a well-recognized L1 gene segment of the human papillomavirus (HPV) type 52 (HPV-52) as the template for experiments, we demonstrate that the LoTemp high-fidelity DNA amplification is attributed to an unusually high processivity and stability of the MHR DNA polymerase whose high fidelity in template-directed DNA synthesis is independent of non-existent 3'–5' exonuclease activity. Further studies and understanding of the characteristics of the LoTemp PCR technology may facilitate implementation of DNA sequencing-based diagnostics at the point of care in community hospital laboratories.
Molecular tests for human papillomavirus (HPV), Chlamydia trachomatis and Neisseria gonorrhoeae in liquid-based cytology specimen
Sin Lee, Veronica S Vigliotti, Suri Pappu
BMC Women's Health , 2009, DOI: 10.1186/1472-6874-9-8
Abstract: A crude proteinase K digestate of 5% of the cells collected in a liquid-based cervicovaginal cytology specimen was used for the detection of DNA molecules specific for HPV, C trachomatis and N gonorrhoeae, and for preparation of materials suitable for direct automated DNA sequencing. Several sets of commercially available polymerase chain reaction (PCR) primers were used to prepare nested PCR amplicons for direct DNA sequencing.Some variants of HPV-16 and HPV-31 were found to share an at least 34-base long sequence homology downstream of the GP5+ binding site, and all HPV-6 and HPV-11 variants shared an upstream 34-base sequence including part of the GP5+ primer. Accurate HPV genotyping frequently required more than 34-bases for sequence alignments to distinguish some of the HPV genotype variants with closely related sequences in this L1 gene hypervariable region. Using the automated Sanger DNA sequencing method for parallel comparative studies on split samples and to retest the residues of samples previously tested positive for C trachomatis and/or for N gonorrhoeae, we also found false-negative and false-positive results as reported by two commercial nucleic acid test kits.Identification of a signature DNA sequence by the automated Sanger method is useful for validation of HPV genotyping and for molecular testing of C trachomatis and N gonorrhoeae in liquid-based cervicovaginal Papanicolaou (Pap) cytology specimens for clinical laboratories with experience in molecular biology to increase the specificity of these DNA-based tests. However, even a highly specific test for high-risk HPV genotyping may have unacceptably low positive predictive values for precancer lesion in populations with a low cervical cancer prevalence rate.Human papillomavirus (HPV), Chlamydia trachomatis and Neisseria gonorrhoeae are the causative agents for the three most common sexually transmitted infections in women. Newly introduced laboratory diagnostic procedures for these infectious agen
Implications of the muon anomalous magnetic moment and Higgs-mediated flavor changing neutral currents
Sin Kyu Kang,Kang Young Lee
Physics , 2001, DOI: 10.1016/S0370-2693(01)01173-X
Abstract: In the light of the recent measurement of the muon anmalous magnetic moment $a_\mu$ by the Muon $(g-2)$ Collaboration, we examine the contribution to $a_\mu$ from the exchange of flavor changing scalars. Assuming that the heavier generations have larger flavor changing couplings, we obtain a bound on $\mu - \tau$ Yukawa coupling for a given scalar mass. Constraints on other flavor changing/conserving couplings are also obtained from the lepton flavor violating decays of muon and tau lepton, and bounds on the branching ratio of $\tau \to 3 e$, $\mu \to 3 e$ and $\tau \to e \mu e$ processes are predicted.
Duality in SU(N) x SU(N') Product Group from M theory
Julian Lee,Sang-Jin Sin
Physics , 1998, DOI: 10.1142/S0217732399000584
Abstract: We generalize the M-theoretic duality of Schmaltz and Sundrum to the product group SU(N) x SU(N') case. We show that the type IIA brane configurations for dual gauge theories are in fact two special limits of the same M-theory 5-brane, just as in the case of the simple SU(N) group.
Wilson Loop and Dimensional Reduction in Non-Commutative Gauge Theories
Sunggeun Lee,Sang-Jin Sin
Physics , 2001, DOI: 10.1103/PhysRevD.64.086002
Abstract: Using the AdS/CFT correspondence we study UV behavior of Wilson loops in various noncommutative gauge theories. We get an area law in most cases and try to identify its origin. In D3 case, we may identify the the origin as the D1 dominance over the D3: as we go to the boundary of the AdS space, the effect of the flux of the D3 charge is highly suppressed, while the flux due to the D1 charge is enhenced. So near the boundary the theory is more like a theory on D1 brane than that on D3 brane. This phenomena is closely related to the dimensional reduction due to the strong magnetic field in the charged particle in the magnetic field. The linear potential is not due to the confinement by IR effect but is the analogue of Coulomb's potential in 1+1 dimension.
Visualization Techniques in Smart Grid  [PDF]
Dao Viet Nga, Ong Hang See, Do Nguyet Quang, Chee Yung Xuen, Lai Lee Chee
Smart Grid and Renewable Energy (SGRE) , 2012, DOI: 10.4236/sgre.2012.33025
Abstract: Visualization is an established methodology in scientific computing. It has been used in many fields because of its strong capability in large data management and information display. However, its applications in power systems, especially in Smart Grid are still in infancy stage. Besides, while there were a lot of researches working on visualizing data in transmission power system, the study on displaying distribution power system data was limited. Therefore, in this paper, author proposed some techniques to visualize the Smart Grid data at distribution. They are classified in three categories, which are low dimensional techniques, multivariate high dimensional techniques and Geographical Information System (GIS) techniques.
1-Chloromethyl-6,7-dimethoxy-3,4-dihydro-1H-isoquinoline-2-sulfonic acid amide, a derivative of tetrahydroisoquinoline, induces granulocytic differentiation of the human leukemic HL-60 cells via G0/G1 phase arrest  [PDF]
Sung-Min Ju, Hyun-Ock Pae, Won-Sin Kim, Chai-Ho Lee, Byung-Hun Jeon
Health (Health) , 2013, DOI: 10.4236/health.2013.55A001
Abstract:

Tetrahydroisoquinolines are known to have various biological effects, including antitumor activity. This study investigated the effect of 1-chloromethyl-6, 7-dimethoxy-3, 4-dihydro-1H-isoquinoline-2-sulfonic acid amide (CDST), a newly synthesized anticancer agent, on cellular differentiation and proliferation in HL-60 cells. Differentiation and proliferation of HL-60 cells were determined through expression of CD11b and CD14 surface antigens using flow cytometry and nitroblue tetrazolium (NBT) assay, and through analysis of cell cycle using propidium iodide staining, western blot analysis and immunoprecipitation, respectively. CDST induced the differentiation of HL-60, as shown by increased expression of differentiation surface antigen CD11b (but no significant change in CD14 expression) and increased NBT-reducing functional activity. DNA flow cytometry analysis indicated that CDST markedly induced a G0/G1 phase arrest of HL-60 cells. Subsequently, we examined the expre-ssion of G0/G1 phase cell cycle-related proteins, including cyclin-dependent kinases (CDKs), cyclins and cyclin dependent kinase inhibitors (CKIs), during the differentiation of HL-60. The levels of CDK2, CDK6, cyclin E and cyclin A were decreased, whereas steady-state levels of CDK4 and cyclin D1 were unaffected. The expression of the p27Kip1 was markedly increased by CDST, but not p21WAF1/Cip1. Moreover, CDST markedly enhanced the binding of p27Kip1 with CDK2 and CDK6, resulting in the reduced activity of

The combination effect of sodium butyrate and 5-Aza-2'-deoxycytidine on radiosensitivity in RKO colorectal cancer and MCF-7 breast cancer cell lines
Hang Cho, Sin Kim, Kee Kim, Won Kang, Ji kim, Seong Oh, Jeong Kim, Chang An
World Journal of Surgical Oncology , 2009, DOI: 10.1186/1477-7819-7-49
Abstract: In this study, we used RKO colorectal cancer cell line and MCF-7 breast cancer cell lines and normal colon cell lines. On each of the cell lines, we used three different agents: the HDAC inhibitor sodium butyrate(SB), the demethylating agent 5-Aza-2'-deoxycytidine(5-aza-DC), and radiation. We then estimated the percentage of the cell survival using the XTT method and experimented to determine if there was an augmentation in the therapeutic effect by using different combinations of the two or three of the treatment methods.After treatment of each cell lines with 5-aza-DC, SB and 6 grays of radiation, we observed that the survival fraction was lower after the treatment with 5-aza-DC or SB than with radiation alone in RKO and MCF-7 cell lines(p < 0.001). The survival fraction was lowest when the two agents, 5-aza-DC and SB were combined with radiation in both RKO and MCF-cell lines.In conclusion, 5-aza-DC and SB can enhance radiosensitivity in both MCF-7 and RKO cell lines. The combination effect of a demethylating agent and an HDAC inhibitor is more effective than that of single agent treatment in both breast and colon cancer cell lines.Epigenetics is an important intracellular procedure that can change the genetic information of the cells that is transmitted during cell division without changing the sequences of the DNA bases [1]. Of the mechanisms of epigenetics, methylation of DNA and histone alteration are related to carcinogenesis.DNA methylation is carried out by DNMT (DNA methyltransferase), usually when a methyl group is added to the cytosine residue of a CpG island, which is a group of repeated CpG sequences [2]. Aberrant methylation of DNA has an important role in controlling genes and epithelial carcinogenesis. When methylation of the CpG island which is at the promoter region of the genetic sequence, occurs the transcription of the gene is suppressed. If hypermethylation occurs at the promoter region of the tumor suppressor genes, transcription is inhibite
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