Chimeric DNA-templated silver nanoclusters as new fluorogenic probes for biosensing applications

Over a decade of research on DNA-templated silver nanoclusters (DNA-AgNCs), this material has now been recognised as an alternative to the conventional fluorescent probes (i.e. quantum dots and organic fluorophores). The DNA-AgNCs have been widely reported for biosensing application due to their design versatility and easy integration with functional DNA sequences. Notwithstanding, a good DNA-AgNCs design is crucial to generate a successful sensing result. Among all of the reported designs, chimeric DNA-AgNCs, i.e. placing AgNCs nucleation sequence and functional sequence in a single DNA strand, is relatively underexplored. This is because the chimeric DNA-AgNCs often exhibit fluorescence turn-off response whereby its accuracy could be affected by false results. However, the simplicity of the chimeric design deserves further investigation, considering it is more cost-effective and enables conclusive results on principles of detection. In this thesis, the principles of chimeric DNA-AgNCs were applied on two test models of distinctive sizes, i.e. adenosine (small analyte) and telomerase (macromolecule). For both studies, an identical AgNCs nucleation sequence, termed Ct9 was integrated with different functional sequences: (1) aptamer for specific recognition of adenosine; and (2) primer for telomerase binding. For adenosine study, the sensing performance of DNA-AgNCs was evaluated by systemically positioning the AgNCs nucleation sequence across the DNA template (i.e. 5’-end, 3’-end or in the middle of DNA template). Among the three formulations, only 5’-end design showed fluorescence enhancement upon binding to adenosine, which is attributable to the structural reformation of anti-parallel G-quadruplexes. In contrast, the 3’-end design showed fluorescence quenching. The reason behind this quenching effect is not fully understand. The study on detection of telomerase activity has indicated that parallel G-quadruplex conformation was able to induce a quenching effect. However, the microenvironment of complex buffer (e.g. TRAP buffer) is required to ensure a consistent turn-off signal, independent of the size of parallel G-quadruplex. In summary, these studies have provided an insight on the principles of detection using DNA-AgNCs. The basic guidelines from the findings not only enable improvement on the formulation of chimeric DNA-AgNCs-derived aptasensors, but also expand their possible biosensing applications

A retrospective study of magnetic resonance-guided focused ultrasound ablation for uterine myoma in Taiwan

AbstractObjectiveTo report our experiences with 40 patients who were treated with magnetic resonance-guided focused ultrasound surgery (MRgFUS) for uterine fibroids and their 6-month follow-up status.Materials and MethodsA total of 40 patients with uterine fibroids underwent MRgFUS from January 2009 to November 2011. The Uterine Fibroid Symptoms and Quality of Life Questionnaire was used to determine the patients' Symptom Severity Scores (SSS) prior to and 6 months after treatment. The nonperfused volume (NPV) values and NPV ratio were obtained immediately at the end of the treatment and at 6 months follow-up.ResultsNo procedure-related complications were noted throughout the 6-month follow-up period among the 40 patients who underwent MRgFUS for uterine fibroids. The mean reduction in SSS in our patients after 6 months was 43.7%, and the mean reduction of fibroid volume was 31.7%. In addition, the mean reduction of NPV and mean NPV ratio was 52.7% and 33.3%, respectively.ConclusionThe results obtained from this study demonstrated that MRgFUS can be safely and effectively used to ablate uterine fibroids to produce a significant decrease in mean fibroid volume and improve SSS for up to 6 months after treatment

Process development of chromatography-based purification on pandemic influenza virus-like particle based vaccines

Since 2013, the H7N9 avian influenza virus is considered a threat to global public health. The development of the H7N9 avian influenza vaccine is one of the most effective strategies to prevent influenza pandemics. Virus-like particles (VLPs) influenza vaccines is non-infectious viral structural proteins. Not only to retain the ability to produce neutralizing antibodies against to viral surface protein, but also safer than the conventional inactivated vaccines. In our previous study, we successfully expressed three structural proteins, hemagglutinin (HA), neuraminidase (NA) and matrix (M1) from influenza A / Taiwan / 1/2013 (H7N9) of the VLP in insect cells. In this study, we present a downstream purification method for the VLP platform. The purification process involves microfiltration, chromatography (using ion exchange, affinity and gel filtration combinations), concentration, diafiltration and sterile filtration steps. In this study, 600 ml of the harvest from the baculovirus expression system was used. The characteristics of VLP volume were examined by HA assay, SDS-PAGE and negative staining transmission electron microscopy (TEM). The overall recovery of HA protein was approximately 38%. In the evaluation of immunized mouse, such virus particles have been shown the HI titer \u3e256. This study demonstrated the chromatographic-based purification process can provide an effective VLP vaccine production for the preparation of the H7N9 influenza pandemic

Anti-AIDS agents 83. Efficient microwave-assisted one-pot preparation of angular 2,2-dimethyl-2H-chromone containing compounds

A novel and efficient microwave-assisted one-pot reaction was developed to synthesize angular 2,2-dimethyl-2H-chromone containing compounds, which is the first and key step in the synthesis of potent DCK and DCP anti-HIV agents. The newly developed microwave synthesis conditions dramatically shortened the reaction time from 2 days to 4 hours with improved yields

Antitumor Agents 286. Design, Synthesis, and Structure−Activity Relationships of 3′ R ,4′ R -Disubstituted-2′,2′-dimethyldihydropyrano[2,3- f ]chromone (DSP) Analogues as Potent Chemosensitizers to Overcome Multidrug Resistance

In this study, various 3′R,4′R-disubstituted-2′,2′-dimethydihydropyrano[2,3-f]chromone (DSP) derivatives were discovered as potent chemosensitizers in the treatment of multidrug resistant cancer cells. Twenty-four DSP analogs (5–28) were synthesized and evaluated against a multi-drug resistant (MDR) cell line (KB-Vin) with and without vincristine (VCR). All DSP analogs exhibited low intrinsic cytotoxicity. However, in combination treatment, most DSPs reversed resistance to VCR and lowered the GI50 value of VCR by 12–349-fold. At a concentration of 1μg/mL, three compounds, 11, 14 and 21, fully reversed resistance to VCR in KB-Vin cancer cells, a twofold increase compared to verapamil, a first generation chemosensitizer. Detailed structure-activity relationship (SAR) conclusions were established based on 3′ and 4′ substitutions. Moreover, a preliminary mechanism study indicated that the chemosensitizing activity of DSP analogs results from inhibition of P-glycoprotein (P-gp) over-expressed in MDR cancer cells.

cDNA Microarray Gene Expression Profiling of Hedgehog Signaling Pathway Inhibition in Human Colon Cancer Cells

Hedgehog (HH) signaling plays a critical role in normal cellular processes, in normal mammalian gastrointestinal development and differentiation, and in oncogenesis and maintenance of the malignant phenotype in a variety of human cancers. Increasing evidence further implicates the involvement of HH signaling in oncogenesis and metastatic behavior of colon cancers. However, genomic approaches to elucidate the role of HH signaling in cancers in general are lacking, and data derived on HH signaling in colon cancer is extremely limited.To identify unique downstream targets of the GLI genes, the transcriptional regulators of HH signaling, in the context of colon carcinoma, we employed a small molecule inhibitor of both GLI1 and GLI2, GANT61, in two human colon cancer cell lines, HT29 and GC3/c1. Cell cycle analysis demonstrated accumulation of GANT61-treated cells at the G1/S boundary. cDNA microarray gene expression profiling of 18,401 genes identified Differentially Expressed Genes (DEGs) both common and unique to HT29 and GC3/c1. Analyses using GenomeStudio (statistics), Matlab (heat map), Ingenuity (canonical pathway analysis), or by qRT-PCR, identified p21(Cip1) (CDKN1A) and p15(Ink4b) (CDKN2B), which play a role in the G1/S checkpoint, as up-regulated genes at the G1/S boundary. Genes that determine further cell cycle progression at G1/S including E2F2, CYCLIN E2 (CCNE2), CDC25A and CDK2, and genes that regulate passage of cells through G2/M (CYCLIN A2 [CCNA2], CDC25C, CYCLIN B2 [CCNB2], CDC20 and CDC2 [CDK1], were down-regulated. In addition, novel genes involved in stress response, DNA damage response, DNA replication and DNA repair were identified following inhibition of HH signaling.This study identifies genes that are involved in HH-dependent cellular proliferation in colon cancer cells, and following its inhibition, genes that regulate cell cycle progression and events downstream of the G1/S boundary

Mesenchymal Stromal Cell-Derived Interleukin-6 Promotes Epithelial–Mesenchymal Transition and Acquisition of Epithelial Stem-Like Cell Properties in Ameloblastoma Epithelial Cells

pithelial–mesenchymal transition (EMT), a biological process associated with cancer stem-like or cancer-initiating cell formation, contributes to the invasiveness, metastasis, drug resistance, and recurrence of the malignant tumors; it remains to be determined whether similar processes contribute to the pathogenesis and progression of ameloblastoma (AM), a benign but locally invasive odontogenic neoplasm. Here, we demonstrated that EMT- and stem cell-related genes were expressed in the epithelial islands of the most common histologic variant subtype, the follicular AM. Our results revealed elevated interleukin (IL)-6 signals that were differentially expressed in the stromal compartment of the follicular AM. To explore the stromal effect on tumor pathogenesis, we isolated and characterized both mesenchymal stromal cells (AM-MSCs) and epithelial cells (AM-EpiCs) from follicular AM and demonstrated that, in in vitro culture, AM-MSCs secreted a significantly higher level of IL-6 as compared to the counterpart AM-EpiCs. Furthermore, both in vitro and in vivo studies revealed that exogenous and AM-MSC-derived IL-6 induced the expression of EMT- and stem cell-related genes in AM-EpiCs, whereas such effects were significantly abrogated either by a specific inhibitor of STAT3 or ERK1/2, or by knockdown of Slug gene expression. These findings suggest that AM-MSC-derived IL-6 promotes tumor-stem like cell formation by inducing EMT process in AM-EpiCs through STAT3 and ERK1/2-mediated signaling pathways, implying a role in the etiology and progression of the benign but locally invasive neoplasm. Stem Cells 2017;35:2083–2094. © 2017 AlphaMed Pres