α-Actinin-4 regulates cancer stem cell properties and chemoresistance in cervical cancer.

Cancer stem cells (CSCs) initiate tumors and possess the properties of self-renewal and differentiation. Since they are responsible for chemoresistance, CSCs are known to be a key factor in cancer recurrence. α-Actinin-4 (ACTN4) is an actin-binding protein that is involved in muscle differentiation and cancer metastasis. It promotes epithelial to mesenchymal transition and cell cycle progression via ß-catenin stabilization in cervical cancer. In the present study, we investigated the role of ACTN4 in regulating cancer cell stemness and chemoresistance in cervical cancer. Results from the gene expression database analysis showed that ACTN4 mRNA expression was elevated in cancerous cervices when compared with normal cervices. Furthermore, ACTN4 knockdown suppressed sphere formation and CSC proliferation. It also decreased CSC size and CD44high/CD24low cell population. ACTN4-knockdown CSCs were sensitive to anticancer drugs, which was observed by down-regulation of the ATP-binding cassette family G2 involved in drug resistance. Finally, ACTN4-knockdown CSCs formed reduced tumors in vivo when compared with control CSCs. Overall, these findings suggest that ACTN4 regulates CSC properties and contributes to chemoresistance in cervical cancer.

Protopine isolated from Nandina domestica induces apoptosis and autophagy in colon cancer cells by stabilizing p53.

The tumor suppressor p53 plays essential roles in cellular protection mechanisms against a variety of stress stimuli and its activation induces apoptosis or autophagy in certain cancer cells. Here, we identified protopine, an isoquinoline alkaloid isolated from Nandina domestica, as an activator of the p53 pathway from cell-based natural compound screening based on p53-responsive transcription. Protopine increased the p53-mediated transcriptional activity and promoted p53 phosphorylation at the Ser15 residue, resulting in stabilization of p53 protein. Moreover, protopine up-regulated the expression of p21WAF1/CIP1 and BAX, downstream genes of p53, and inhibited the proliferation of HCT116 colon cancer cells. Apoptosis was elicited by protopine as indicated by caspase-3/7 activation, poly ADP ribose polymerase cleavage, and increased population of Annexin V-FITC-positive cells. Furthermore, protopine induced the formation of microtubule-associated protein 1 light chain 3 (LC3) puncta and LC3-II turnover, typical biochemical markers of autophagy, in HCT116 cells. Our findings suggest that protopine exerts its antiproliferative activity by stimulating the p53 pathway and may have potential as a chemopreventive agent for human colon cancer.

A centrifugally actuated point-of-care testing system for the surface acoustic wave immunosensing of cardiac troponin I.

A fully automated point-of-care testing (POCT) system with a surface acoustic wave (SAW) immunosensor was developed for rapid and sensitive detection of cardiac troponin I (cTnI) in body fluid (plasma and whole blood). The assay, based on gold nanoparticle sandwich immunoassay and subsequent gold staining, was performed on the SAW immunosensor packaged inside a disposable microfluidic cartridge. The entire fluidic process, including plasma separation, reagent transport, metering, and mixing, was carried out by controlling the centrifugal force acting on the rotating cartridge and laser-irradiated ferrowax microvalves. On investigation of sensor response to various cTnI concentrations, the system exhibited a high performance with a detection limit of 6.7 pg mL(-1), and the coefficient of variation was less than 10% over the entire test range (10 pg mL(-1) to 25 ng mL(-1)). On comparing this POCT system with a clinically utilized system in a physical laboratory (Centaur® XP; Siemens), a correlation coefficient of 0.998 was found, validating the diagnostic capability of the SAW immunosensor.

[Delirium Experience of the Intensive Care Unit Patients].

PURPOSE: The study aimed to understand the delirium experience of intensive care unit (ICU) patients. METHODS: We performed a qualitative study using Colaizzi's phenomenological method. Eleven patients, who experienced delirium according to the Confusion Assessment Method for ICU, participated after transferring to general wards from the ICU. Individual in-depth semi-structured interviews ranging from 30 minutes to 2 hours in length were conducted between November 2018 and August 2019. RESULTS: Nine themes and four theme clusters emerged. The four theme clusters were: 1) "Overwhelmed by fear," which describes the experience of a patient close to death and the feeling of difficulty in understanding disorganized thinking; 2) "Anxious about not understanding the situation," which means that patients' sense of time and space were disordered in the ICU; 3) "Being deserted," which indicates the feeling of being separated from others and yourself; and 4) "Resistance to protect my dignity," which indicates that the dignity and autonomy of an individual in the patient's position at the ICU, are ignored. CONCLUSION: Nursing interventions are needed that would enable patients to maintain orientation and self-esteem in the ICU. In addition, healthcare providers need to provide information about the unfamiliar environment in the ICU in advance.

Thermoresponsive pore structure of biopolymer microspheres for a smart drug carrier.

Triggering changes in surface porosity enabled the controlled release of biomolecules from elastin-like polypeptide (ELP) microspheres. The transition temperature (T(t)) of cross-linked microspheres was determined by differential scanning calorimetry, and T(t) was in agreement with the volume transition observed by changing the external temperature of the incubation media. The thermoresponsive pore structure of ELP microspheres and their surface morphology were examined by field-emission scanning electron microscopy. ELP microspheres were investigated as a smart drug carrier using model drug molecules, bovine serum albumin, and prednisone acetate. The release rate was accelerated by squeezing out the entrapped biomolecules as the temperature was increased above T(t) because of the development of micropores at the surface as well as in the bulk. In addition, the stepwise release confirmed that ELP microspheres could be progammed precisely to control the release of drugs by external stimuli.

Current issues and areas for improvement in the Korean Dental Hygienist National Licensing Examination: an expert Delphi survey among dental hygienists.

PURPOSE: This study aimed to investigate current issues and areas for improvement in the Korean Dental Hygienist National Licensing Examination (KDHNLE) through an expert Delphi survey. METHODS: A Delphi survey was conducted from May through August 2016 in Korea. This Delphi survey included 20 persons representing the field of dental hygiene (7 groups from various dental hygiene-related organizations). The Delphi survey was administered through e-mail as 3 rounds of questionnaire surveys regarding the issues facing the KDHNLE and potential solutions to those challenges. The primary Delphi survey was an open questionnaire. In each round, subjects' responses were categorized according to the detailed themes of their responses. The minimum value of the content validity ratio of the survey results was determined by the number of panels participating in the Delphi survey. RESULTS: Issues facing the KDHNLE were identified from the results of the Delphi survey. The following 4 items had an average importance score of 4.0 or higher and were considered as important by over 85% of the panels: the failure of the practical test to reflect actual clinical settings, the focus of the practical test on dental scaling, the gap between the items evaluated on the national examination and actual practical work, and insufficiency in strengthening the expertise of licensed dental hygienists. The following items were suggested for improvement: more rigorous rater training, adjustment of the difficulty of the licensing examination, the introduction of a specialized dental hygienist system, and more rigorous refresher training for licensed dental hygienists. CONCLUSION: Based on the above results, the KDHNLE should be improved according to the core competencies of dental hygienists, including on-site clinical practice experience.

Amphiphilic comblike polymers enhance the colloidal stability of Fe(3)O(4) nanoparticles.

Stable colloidal dispersions of magnetite (Fe(3)O(4)) nanoparticles (MNPs) were obtained with the inclusion of an amphiphilic comblike polyethylene glycol derivative (CL-PEG) as an amphiphilic polymeric surfactant. Both the size and morphology of the resulting CL-PEG-modified MNPs could be controlled and were characterized by transmission electron microscopy (TEM). The interaction between MNPs and CL-PEG was confirmed by the presence of characteristic infrared absorption peaks, and the colloidal stability of the nanoparticle dispersion in water was evaluated by long-term observation of the dispersion using UV-visible spectroscopy. SQUID measurements confirmed the magnetization of CL-PEG-modified MNPs. The zeta potential of the CL-PEG-modified MNPs showed a dramatic conversion from positive to negative in response to the pH of the surrounding aqueous medium due to the presence of carboxyl groups at the surface. These carboxyl groups can be used to functionalize the MNPs with biomolecules for biotechnological applications. However, regardless of surface electrostatics, the flexible, hydrophilic side chains of CL-PEG-modified MNPs prevented the approach of adjacent nanoparticles, thereby resisting aggregation and resulting in a stable aqueous colloid. The cytotoxicity of MNPs and CL-PEG-modified MNPs was evaluated by a MTT assay.

Simple fabrication of a smart microarray of polystyrene microbeads for immunoassay.

We describe a simple method to fabricate an array of polystyrene microbeads (PS microbeads) conjugated with an elastin-like polypeptide (ELP) on a glass surface using a removable polymer template (RPT). A thin layer of adhesive was spun-cast on glass and cured by UV radiation. Micropatterns of an RPT were then transferred onto the surface by microcontact printing. The adhesion of PS microbeads on the surface depended on the adhesion performance of the adhesive layer, which could be adjusted by irradiation time. An array of PS microbeads conjugated with ELP was used for a smart immunoassay of prostate-specific antigen (PSA), a cancer marker. By controlling the phase transition of ELP molecules, PSA molecules were selectively adhered or released from the bead surface. The selective and reversible binding of PSA molecules on the bead surface was characterized with fluorescence microscopy.

Polypeptide-mediated switchable microarray of bacteria.

This paper describes a feasible solution for the bacterial cell death and contamination from cell division that occurs in microfluidic applications. The method adopts a smart thermoresponsive surface, highly resolved micropatterns, and surface-functionalized bacteria tagged with thermoresponsive molecules. We developed a method for controllable bacterial attachment and detachment using an elastin-like polypeptide (ELP). To create a smart surface with switchable properties, the surface of a glass substrate was conjugated with thermoresponsive ELP molecules. The attachment of bacterial cells to the ELP surface was induced by the hydrophobic affinity of the ELPs on the glass surface to tagged ELPs on the bacterial surface. A cell-repellent polymer was micropatterned to create a highly resolved space for specific bacterial adhesion. Reversible bacterial attachment and detachment was achieved by controlling the thermoresponsive phase transition of ELP molecules. Five different types of bacteria were successfully conjugated with ELPs and arrayed on the surface. The viability of the bacteria that had attached to the surface was evaluated by determining colony forming units of released bacteria on an agar plate.

Enhanced surface plasmon resonance by Au nanoparticles immobilized on a dielectric SiO2 layer on a gold surface.

This paper introduces strategies for enhancement of a surface plasmon resonance (SPR) signal by adopting colloidal gold nanoparticles (AuNPs) and a SiO(2) layer on a gold surface. AuNPs on SiO(2) on a gold surface were compared with an unmodified gold surface and a SiO(2) layer on a gold surface with no AuNPs attached. The modified surfaces showed significant changes in SPR signal when biomolecules were attached to the surface as compared with an unmodified gold surface. The detection limit of AuNPs immobilized on a SPR chip was 0.1 ng mL(-1) for the prostate-specific antigen (PSA), a cancer marker, as measured with a spectrophotometer. Considering that the conventional ELISA method can detect approximately 10 ng mL(-1) of PSA, the strategy described here is much more sensitive (approximately 100 fold). The enhanced shift of the absorption curve resulted from the coupling of the surface and particle plasmons by the SiO(2) layer and the AuNPs on the gold surface.

A cell-repellent sulfonated PEG comb-like polymer for highly resolved cell micropatterns.

This paper investigates the chemical modification of a cell-repellent poly(ethylene glycol) (PEG)-based polymer to enhance its hydrophilicity with sulfonate groups, and its application in the fabrication of a cell microarray. First, a polymer comprised of a methyl methacrylate (MMA) backbone with PEG side-chains (PMMA-b-PEG) was synthesized from three monomers by radical polymerization and purified. Despite the hydrophilic side-groups in the amphiphilic polymer, the backbone structure's hydrophobicity allows for local adsorption of biomolecules in incubation media with or without serum. To enhance the hydrophilicity of the polymer, we tethered sulfonate groups to the hydroxyl groups on the PEG side chains (PMMA-b-PEG-SO3). The sulfate groups' physical and mechanical movement competitively repels biomolecules approaching the PMMA-b-PEG surface. Polymers modified with sulfonate were characterized by contact angle measurement, FT-IR, NMR, AFM and GPC. PMMA-b-PEG and PMMA-b-PEG-SO3 were successfully micropatterned on polystyrene and glass surfaces, and cell attachment was performed in either serum-free or serum-containing media, resulting in highly resolved cell micropatterns.

"Smart" biopolymer for a reversible stimuli-responsive platform in cell-based biochips.

The rapid response of a smart material surface to external stimuli is critical for application to cell-based biochips. The sharp and controllable phase transition of elastin-like polypeptide (ELP) enabled reversible cell adhesion on the surface by changing the temperature or salt concentration in the system. First, ELP micropatterns were prepared on a glass surface modified into aldehyde. The lysine-containing ELP (ELP-K) was genetically synthesized from E. coli for conjugation with the aldehyde on the glass surface. The phase transition of ELP was monitored in PBS and cell culture media using UV-visible spectroscopy, and a significant difference in transition temperature (Tt) was observed between the two solution systems. The micropatterning of ELP on the glass surface was performed by microcontact printing a removable polymeric template on the aldehyde-glass followed by incubation in ELP-K aqueous solution. The ELP micropatterns were imaged with atomic force microscopy and showed a monolayer thickness of approximately 4 nm. Imaging from time-of-flight secondary ion mass spectroscopy confirmed that the ELP molecules were successfully immobilized on the highly resolved micropatterns. Cell attachment and detachment could be reversibly controlled on the ELP surfaces by external stimuli. The hydrophobic phase above Tt resulted in the adhesion of fibroblasts, while the detachment of cells was induced by lowering the incubation temperature below Tt. The smart properties of ELP were reliable and reproducible, demonstrating potential applications in cell-based microdevices.

Polystyrene microbeads modified with an elastin-like biopolymer for stimuli-responsive immunodetection.

An efficient and controlled method for immunodetection, using polystyrene (PS) microbeads conjugated with an elastin-like polypeptide (ELP), was investigated. ELP is a temperature-sensitive polymer that exhibits a hydrophilic-hydrophobic phase transition at the lower critical solution temperature. To introduce amine groups, ELP was modified with lysine for conjugation with PS microbeads functionalized with carboxylic groups. Prostate-specific antigen (PSA), a cancer marker, was detected from a biomolecular mixture using ELP-conjugated PS microbeads and ELP-conjugated antiPSA. External stimuli were used to reversibly separate the PSA-antiPSA complex. The stimuli-responsiveness of the ELP provided a designable generic biosurface for diagnostic detection.

Polymeric optical microscreen for high-resolution surface plasmon resonance microarray imaging.

In this study, we demonstrate a simple method to fabricate surface plasmon resonance (SPR) imaging microarrays using polymer micropatterns. The use of a micrometer-scale polymeric optical screen (microPOS) passivates the region deposited with polymer by completely removing SPR signals or by saturating the SPR signal far beyond the detection range of SPR imaging. Two schemes were suggested to create a surface microPOS by either micropatterning a thick insulating layer before deposition of a metal layer (complete removal of SPR) or after deposition of a metal layer (saturation of SPR signal). The two schemes were successfully applied for the imaging of biological adsorption with a high imaging resolution of approximately 100 microm/pattern and 10 microm separation. The validity of the system was verified with a biotin-streptavidin system as a model for the systematic binding of biomolecules. Further, binding of prostate-specific antigen (PSA) onto the anti-PSA SPR microarray was demonstrated as a useful method for detecting a cancer marker.

Micropatterning of cell-repellent polymer on a glass substrate for the highly resolved virus microarray.

The development of a simple and easily accessible method to control cellular behavior under a spatially controlled surface is critical for fundamental studies in biotechnology. We fabricated a microarray of Spodoptera frugiperda 9 (Sf9) cells on a glass surface by microcontact printing cell-repellent polymeric molecules of poly(ethylene glycol)-branched-poly(methyl methacrylate) as a template for cell micropatterning. The polymer micropatterns enabled the stable confinement of Sf9 cells on the surface, resulting in the formation of a cell microarray. Subsequently, the patterned Sf9 cells were infected with recombinant baculovirus modified with green fluorescent protein (GFP) to form a virus microarray, and GFP expression in the virus microarray was verified with confocal fluorescence microscopy.

Rescue of Helicobacter pylori-induced cytotoxicity by red ginseng.

Helicobacter pylori has been known to provoke gastric inflammation, ulceration, and DNA damage, based on which WHO defined H. pylori as a class I carcinogen. Although ginseng, the root of Panax ginseng C.A. Meyer, has been reported to possess antiadhesion or antimicrobial activity against H. pylori, in this study, we examined the protective effect of red ginseng extracts (RGE) against H. pylori-induced cytotoxicity and DNA damage. RGE significantly attenuated both H. pylori-induced DNA damage assessed by comet assay and apoptosis measured by DNA fragmentation. Inactivation of ERK1/2 signaling and attenuation of caspase-3 activation and PARP cleavage were revealed with RGE against H. pylori infection. RGE decreased H. pylori-stimulated IL-8 gene expression, which resulted from the transcriptional regression of NF-kappaB. In conclusion, RGE showed significant gastroprotective effects against H. pylori-associated gastric mucosal cell damage, suggesting that red ginseng could be used as a medicinal phytonutrient against H. pylori infection.