In vitro and in vivo studies on exogenous polyamines and α-difluoromethylornithine to enhance bone formation and suppress osteoclast differentiation.

Exogenous polyamines, including putrescine (PUT), spermidine (SPD), and spermine (SPM), and the irreversible inhibitor of the rate-limiting enzyme ornithine decarboxylase (ODC) of polyamine biosynthesis, α-difluoromethylornithine (DFMO), are implicated as stimulants for bone formation. We demonstrate in this study the osteogenic potential of exogenous polyamines and DFMO in human osteoblasts (hOBs), murine monocyte cell line RAW 264.7, and an ovariectomized rat model.

Novel Aptamer-Based Small-Molecule Drug Screening Assay to Identify Potential Sclerostin Inhibitors against Osteoporosis.

A novel aptamer-based competitive drug screening platform for osteoporosis was devised in which fluorescence-labeled, sclerostin-specific aptamers compete with compounds from selected chemical libraries for the binding of immobilized recombinant human sclerostin to achieve high-throughput screening for potential small-molecule sclerostin inhibitors and to facilitate drug repurposing and drug discovery. Of the 96 selected inhibitors and FDA-approved drugs, six were shown to result in a significant decrease in the fluorescence intensity of the aptamer, suggesting a higher affinity toward sclerostin compared with that of the aptamer. The targets of these potential sclerostin inhibitors were correlated to lipid or bone metabolism, and several of the compounds have already been shown to be potential osteogenic activators, indicating that the aptamer-based competitive drug screening assay offered a potentially reliable strategy for the discovery of target-specific new drugs.

Suppression of Breast Cancer Cell Migration by Small Interfering RNA Delivered by Polyethylenimine-Functionalized Graphene Oxide.

The carbon-based nanomaterial graphene can be chemically modified to associate with various molecules such as chemicals and biomolecules and developed as novel carriers for drug and gene delivery. In this study, a nonviral gene transfection reagent was produced by functionalizing graphene oxide (GO) with a polycationic polymer, polyethylenimine (PEI), to increase the biocompatibility of GO and to transfect small interfering RNA (siRNA) against C-X-C chemokine receptor type 4 (CXCR4), a biomarker associated with cancer metastasis, into invasive breast cancer cells. PEI-functionalized GO (PEI-GO) was a homogeneous aqueous solution that remained in suspension during storage at 4 °C for at least 6 months.

Molecular and epidemiological study of enterovirus D68 in Taiwan.

Background/purpose: As an immunofluorescence assay for enterovirus D68 (EV-D68) is not available in the enteroviruses surveillance network in Taiwan, EV-D68 may be the actual pathogen of untypeable enterovirus-suspected isolates.

Methods: The untypeable isolates collected from 2007 through 2014 were identified by nucleic acid amplification-based methods and sequencing of the VP1 region to analyze the phylogeny and epidemiology of EV-D68 in Taiwan.

Results: Twenty-nine EV-D68 isolates were sequenced, including 15 Cluster 3 and 14 Cluster 1 viruses.

Molecular epidemiological analysis of Saffold cardiovirus genotype 3 from upper respiratory infection patients in Taiwan.

Background: Saffold cardiovirus (SAFV) belongs to the Cardiovirus genus of Picornaviridae family, and may be a relevant new human pathogen; Thus far, eleven genotypes have been identified. The SAFV type 3 (SAFV-3) is thought to be the major genotype and is detected relatively frequently in children with acute gastroenteritis and respiratory illness. The epidemiology and pathogenicity of SAFV-3 remain unclear.

Suppression of ornithine decarboxylase promotes osteogenic differentiation of human bone marrow-derived mesenchymal stem cells.

Ornithine decarboxylase (ODC) is the rate-limiting enzyme for polyamine biosynthesis. Suppression of ODC by its irreversible inhibitor, α-difluoromethylornithine (DFMO), or by RNA interference through siRNA, enhanced osteogenic gene expression and alkaline phosphatase activity, and accelerated matrix mineralization of human bone marrow-derived mesenchymal stem cells (hBMSCs). Besides, adipogenic gene expression and lipid accumulation was attenuated, indicating that the enhanced osteogenesis was accompanied by down-regulation of adipogenesis when ODC was suppressed.

Molecular and epidemiological study of human parechovirus infections in Taiwan, 2007-2012.

Background/purpose: As routine diagnostic assays for human parechoviruses (HPeVs) have not been included in the enteroviruses surveillance network in Taiwan, HPeVs may be the actual pathogens of hundreds of untypeable enteroviruses-suspected isolates.

Methods: In this study, these untypeable isolates collected from 2007 through 2012 were examined by reverse transcription-polymerase chain reaction (RT-PCR)-based methods to survey the epidemiology of HPeVs in Taiwan.

Results: Thirty-eight HPeV isolates were identified from 575 untypeable isolates, including 23 HPeV type1 (HPeV1), 13 HPeV3, and two HPeV6.

Antigenic and genetic diversity of human enterovirus 71 from 2009 to 2012, Taiwan.

Different subgenogroups of enterovirus 71 (EV-71) have caused numerous outbreaks of hand, foot, and mouth disease worldwide, especially in the Asia-Pacific region. During the development of a vaccine against EV-71, the genetic and antigenic diversities of EV-71 isolates from Taiwan were analyzed by phylogenetic analyses and neutralization tests. The results showed that the dominant genogroups had changed twice, from B to C and from C to B, between 2009 and 2012.

Phylogenetic analysis and development of an immunofluorescence assay for untypeable strains of coxsackievirus B3.

Background/purpose: In recent years, coxsackievirus B3 (CV-B3) has been determined as a dominant enterovirus serotype that may cause severe complications in patients. Since 2008 in Taiwan, some enterovirus isolates have been regarded as untypeable [by employing commercial immunofluorescence assay (IFA) kits]. In 2012, the number of isolates increased.

Exogenous polyamines promote osteogenic differentiation by reciprocally regulating osteogenic and adipogenic gene expression.

Polyamines are naturally occurring organic polycations that are ubiquitous in all organisms, and are essential for cell proliferation and differentiation. Although polyamines are involved in various cellular processes, their roles in stem cell differentiation are relatively unexplored. In this study, we found that exogenous polyamines, putrescine, spermidine, and spermine, promoted osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) without inducing cell death or apoptosis.

Delivery of small interfering RNAs in human cervical cancer cells by polyethylenimine-functionalized carbon nanotubes.

Carbon nanotubes are capable of penetrating the cell membrane and are widely considered as potential carriers for gene or drug delivery. Because the C-C and C=C bonds in carbon nanotubes are nonpolar, functionalization is required for carbon nanotubes to interact with genes or drugs as well as to improve their biocompatibility. In this study, polyethylenimine (PEI)-functionalized single-wall (PEI-NH-SWNTs) and multiwall carbon nanotubes (PEI-NH-MWNTs) were produced by direct amination method.

Characterization of oseltamivir-resistant influenza A(H1N1)pdm09 viruses in Taiwan in 2009-2011.

The early isolated swine-origin influenza A(H1N1)pdm09 viruses were susceptible to oseltamivir; however, there is a concern about whether oseltamivir-resistant influenza A(H1N1)pdm09 viruses will spread worldwide as did the oseltamivir-resistant seasonal influenza A(H1N1) viruses in 2007-2008. In this study, the frequency of oseltamivir resistance in influenza A(H1N1)pdm09 viruses was determined in Taiwan. From May 2009 to April 2011, 1,335 A(H1N1)pdm09-positive cases in Taiwan were tested for the H275Y mutation in the neuraminidase (NA) gene that confers resistance to oseltamivir.

Community outbreak of adenovirus, Taiwan, 2011.

In 2011, a large community outbreak of human adenovirus (HAdV) in Taiwan was detected by a nationwide surveillance system. The epidemic lasted from week 11 through week 41 of 2011 (March 14-October 16, 2011). Although HAdV-3 was the predominant strain detected (74%), an abrupt increase in the percentage of infections caused by HAdV-7 occurred, from 0.

Phylogenetic and evolutionary history of influenza B viruses, which caused a large epidemic in 2011-2012, Taiwan.

The annual recurrence of the influenza epidemic is considered to be primarily associated with immune escape due to changes to the virus. In 2011-2012, the influenza B epidemic in Taiwan was unusually large, and influenza B was predominant for a long time. To investigate the genetic dynamics of influenza B viruses during the 2011-2012 epidemic, we analyzed the sequences of 4,386 influenza B viruses collected in Taiwan from 2004 to 2012.

An outbreak of coxsackievirus A6 hand, foot, and mouth disease associated with onychomadesis in Taiwan, 2010.

Background: In 2010, an outbreak of coxsackievirus A6 (CA6) hand, foot and mouth disease (HFMD) occurred in Taiwan and some patients presented with onychomadesis and desquamation following HFMD. Therefore, we performed an epidemiological and molecular investigation to elucidate the characteristics of this outbreak.

Methods: Patients who had HFMD with positive enterovirus isolation results were enrolled.

New variants and age shift to high fatality groups contribute to severe successive waves in the 2009 influenza pandemic in Taiwan.

Past influenza pandemics have been characterized by the signature feature of multiple waves. However, the reasons for multiple waves in a pandemic are not understood. Successive waves in the 2009 influenza pandemic, with a sharp increase in hospitalized and fatal cases, occurred in Taiwan during the winter of 2010.

Reassortment and mutations associated with emergence and spread of oseltamivir-resistant seasonal influenza A/H1N1 viruses in 2005-2009.

A dramatic increase in the frequency of the H275Y mutation in the neuraminidase (NA), conferring resistance to oseltamivir, has been detected in human seasonal influenza A/H1N1 viruses since the influenza season of 2007-2008. The resistant viruses emerged in the ratio of 14.3% and quickly reached 100% in Taiwan from September to December 2008.

Genetic diversity and C2-like subgenogroup strains of enterovirus 71, Taiwan, 2008.

Background: Human enterovirus 71 (EV-71) is known of having caused numerous outbreaks of hand-foot-mouth disease, and other clinical manifestations globally. In 2008, 989 EV-71 strains were isolated in Taiwan.

Results: In this study, the genetic and antigenic properties of these strains were analyzed and the genetic diversity of EV-71 subgenogroups surfacing in Taiwan was depicted, which includes 3 previously reported subgenogroups of C5, B5, and C4, and one C2-like subgenogroup.

Early findings of oseltamivir-resistant pandemic (H1N1) 2009 influenza A viruses in Taiwan.

In this study, we investigated the frequency of oseltamivir resistance in pandemic (H1N1) 2009 influenza A viruses in Taiwan and characterized the resistant viruses. From May 2009 to January 2010, 1187 pandemic H1N1 virus-positive cases in Taiwan were tested for the H275Y substitution in the neuraminidase (NA) gene that confers resistance to oseltamivir. Among them, eight hospitalized cases were found to be infected with virus encoding the H275Y substitution in their original specimens collected after oseltamivir treatment.

A new antigenic variant of human influenza A (H3N2) virus isolated from airport and community surveillance in Taiwan in early 2009.

A new variant of influenza A H3N2 virus emerged in January 2009 and became the dominant strain in Taiwan in April 2009. The variant was also detected in imported cases from various regions, including East and Southeast Asia and North America, indicating that it has circulated globally. Compared to the 2009-2010 vaccine strain, A/Brisbane/10/2007, the hemagglutinin gene of this variant exhibited five substitutions, E62K, N144K, K158N, K173Q and N189K, which are located in the antigenic sites E, A, B, D and B respectively, and it was antigenically distinct from A/Brisbane/10/2007 with more than eight-fold titer reduction in the hemagglutination inhibition reaction.

Evolution of infectious bronchitis virus in Taiwan: characterisation of RNA recombination in the nucleocapsid gene.

Avian infectious bronchitis virus (IBV) belongs to the Coronaviridae family and causes significant economic loss in Taiwan (TW), even in flocks that have been extensively immunised with Massachusetts (Mass)-serotype vaccines. Phylogenetic analysis of all non-structural and most structural genes shows that TW IBV is genetically distinct from the US strain and more similar to Chinese (CH) IBV. In contrast, the nucleocapsid (N) gene of TW IBV presents phylogenetic incongruence.

Identification of Taiwan and China-like recombinant avian infectious bronchitis viruses in Taiwan.

Infectious bronchitis virus (IBV) infections in poultry cause great economic losses to the poultry industry worldwide. The emergence of viral variants complicates disease control. The IBV strains in Taiwan were clustered into two groups, Taiwan group I and Taiwan group II, based on the S1 gene.

The circulation of subgenogroups B5 and C5 of enterovirus 71 in Taiwan from 2006 to 2007.

Enteroviruses (EVs) are among the most common pathogens in humans. EV71 infections have caused devastating enterovirus-associated outcomes in children globally. In this study, eleven EV71 isolates in Taiwan during 2006-2007 were selected for N-terminal VP1 gene analysis.

Sequence changes of infectious bronchitis virus isolates in the 3' 7.3 kb of the genome after attenuating passage in embryonated eggs.

Attenuated infectious bronchitis virus (IBV) vaccines are available but the relationship between sequence and virulence is not clear. In this study, the sequences of the 3' 7.3 kb of the genome, amplified using reverse transcription-polymerase chain reaction before and after attenuation, were compared to study the relationship between virulence and the sequences of three IBV strains.