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1.
Med Teach ; 45(4): 368-374, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36288746

RESUMEN

BACKGROUND: The ability of medical students to speak up before a medical error occurs is a timely and necessary interaction to prevent potential patient harm. As it may be crucial to improve patient safety, we explored how medical students react to a medical error and provided them appropriate training regarding speaking up about medical issues. METHODS: A quasi-experimental study was conducted in Taiwan involving 153 medical students who participated in a speaking-up simulation course. They were divided into two groups. The first group participated in a non-life-threatening scenario before the intervention, followed by a personalized debriefing session, then a life-threatening scenario after the intervention. The second group participated in a life-threatening scenario before the intervention, followed by a personalized debriefing session, then a non-life-threatening scenario after the intervention. Students also completed patient safety attitude survey. RESULTS: During the preintervention scenario, the overall medical students' speaking-up rate to medical error was 45.1%. The speaking-up rate of medical students in life-threatening scenario was significantly higher than the rate in non-life-threatening scenario before the intervention (64.6% vs 24.3%, p < 0.001). After personalized debriefing, the speaking-up rate to medical errors was significantly improved both in life-threatening scenarios (95.9%, p < 0.001) and in non-life-threatening scenarios (100%, p < 0.001). Male medical students had significantly higher speaking-up rates than female students in life-threatening scenario (76.2% vs 51.4%, p = 0.02). On post-intervention surveys, students provided several reasons for their likelihood of speaking up or remaining silent during a medical error event. CONCLUSIONS: Medical students' rate of speaking-up to medical error was higher in a simulated life-threatening scenario than in a simulated non-life-threatening scenario. Faculty-led personalized debriefing can facilitate medical students' adoption of communication strategies to speak up more in medical error events. Educators should also consider gender differences when they design effective assertive communication courses.[Box: see text].


Asunto(s)
Entrenamiento Simulado , Estudiantes de Medicina , Humanos , Masculino , Femenino , Errores Médicos/prevención & control , Comunicación , Seguridad del Paciente
2.
BMC Med Educ ; 22(1): 651, 2022 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-36042449

RESUMEN

BACKGROUND: Interprofessional collaborative practice is essential for meeting patients' needs and improving their health outcomes; thus, the effectiveness of interprofessional education (IPE) should be clearly identified. There is insufficient evidence in the literature to determine the outcomes of IPE compared to traditional single-profession education (SPE). This study aimed to compare the outcomes of IPE and SPE during a simulation training course. METHODS: The study design was a mixed-methods, incorporated cross-over design and a qualitative survey. A total of 54 students including 18 medical students and 36 nursing students were recruited from March to April 2019. The 4-week simulation course was designed based on Kolb's experimental learning theory and Bandura's social learning theory. Participants were evenly divided into group 1 (received IPE-learning followed by SPE-learning), and group 2 (received SPE-learning followed by IPE-learning). Students' medical task performance, team behavior performance, teamwork attitude, and patient safety attitude were collected at pretest, mid-test, and posttest. Descriptive statistics and repeated measures analysis of variance were used. End-of-study qualitative feedback was collected, and content analysis was performed. RESULTS: Both groups demonstrated moderate-to-large within-group improvements for multiple learning outcomes at mid-test. Group 1 students' medical task performance (F = 97.25; P < 0.001) and team behavior performance (F = 31.17; P < 0.001) improved significantly. Group 2 students' medical task performance (F = 77.77; P < 0.001), team behavior performance (F = 40.14; P < 0.001), and patient safety attitude (F = 6.82; P < 0.01) improved significantly. Outcome differences between groups were nonsignificant. Qualitative themes identified included: personal factor, professional factor, interprofessional relationship, and learning. The IPE program provided students with exposure to other professions and revealed differences in expertise and responsibilities. CONCLUSION: IPE-simulation and SPE-simulation were effective interventions that enabled medical and nursing students to develop critical medical management and team behavior performance. IPE-simulation provided more opportunities for improving competencies in interprofessional collaborative practice. In circumstances with limited teaching resources, SPE-simulation can be an acceptable alternative to IPE-simulation.


Asunto(s)
Estudiantes de Medicina , Estudiantes de Enfermería , Actitud del Personal de Salud , Humanos , Educación Interprofesional , Relaciones Interprofesionales , Aprendizaje
3.
J Formos Med Assoc ; 120(4): 1090-1099, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33183879

RESUMEN

BACKGROUND/PURPOSE: The evidence provided by syntheses of the preventative effects of gabexate mesilate against pancreatitis among patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) is limited and highly heterogeneous. To enhance the understanding of this topic, this study aimed to provide overview of gabexate mesilate on preventing post ERCP pancreatitis (PEP) by synthesizing all relevant randomized controlled trials (RCTs). METHODS: We searched three databases for relevant RCTs. Two authors independently extracted data of pancreatitis incidence after ERCP, abdominal pain within 48 hours, and hyperamylasemia for quality assessment and meta-analysis. RESULTS: Thirteen RCTs with 3718 patients undergoing ERCP met the eligibility criteria and were included. The results revealed that the use of gabexate mesilate led to lower PEP (Peto odds ratio: 0.66, 95% confidence interval [CI]: 0.49 to 0.89), especially in the subgroup of gabexate mesilate infusion starting more than 30 min (Risk ratio: 0.45, 95% CI: 0.29 to 0.72). CONCLUSION: The present synthesis found that gabexate mesilate could be an option of prophylactic treatment of pancreatitis for patients undergoing ERCP, and reveals that it is favorable to administer it starting 30 min before the ERCP. This evidence may improve the clinical prevention of PEP.


Asunto(s)
Colangiopancreatografia Retrógrada Endoscópica , Gabexato , Pancreatitis , Colangiopancreatografia Retrógrada Endoscópica/efectos adversos , Gabexato/uso terapéutico , Humanos , Pancreatitis/etiología , Pancreatitis/prevención & control , Ensayos Clínicos Controlados Aleatorios como Asunto , Somatostatina
4.
Proc Natl Acad Sci U S A ; 114(21): 5419-5424, 2017 05 23.
Artículo en Inglés | MEDLINE | ID: mdl-28484009

RESUMEN

Synthetic biomimetic matrices with osteoconductivity and osteoinductivity have been developed to regenerate bone tissues. However, whether such systems harbor donor marrow in vivo and support mixed chimerism remains unknown. We devised a strategy to engineer bone tissues with a functional bone marrow (BM) compartment in vivo by using a synthetic biomaterial with spatially differing cues. Specifically, we have developed a synthetic matrix recapitulating the dual-compartment structures by modular assembly of mineralized and nonmineralized macroporous structures. Our results show that these matrices incorporated with BM cells or BM flush transplanted into recipient mice matured into functional bone displaying the cardinal features of both skeletal and hematopoietic compartments similar to native bone tissue. The hematopoietic function of bone tissues was demonstrated by its support for a higher percentage of mixed chimerism compared with i.v. injection and donor hematopoietic cell mobilization in the circulation of nonirradiated recipients. Furthermore, hematopoietic cells sorted from the engineered bone tissues reconstituted the hematopoietic system when transplanted into lethally irradiated secondary recipients. Such engineered bone tissues could potentially be used as ectopic BM surrogates for treatment of nonmalignant BM diseases and as a tool to study hematopoiesis, donor-host cell dynamics, tumor tropism, and hematopoietic cell transplantation.


Asunto(s)
Trasplante de Médula Ósea/métodos , Huesos , Quimerismo , Trasplante de Células Madre Hematopoyéticas/métodos , Ingeniería de Tejidos , Animales , Ratones
5.
Small ; 12(27): 3658-66, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27254278

RESUMEN

To understand the inhomogeneity of cells in biological systems, there is a growing demand on the capability of characterizing the properties of individual single cells. Since single-cell studies require continuous monitoring of the cell behaviors, an effective single-cell assay that can support time lapsed studies in a high throughput manner is desired. Most currently available single-cell technologies cannot provide proper environments to sustain cell growth and, proliferation of single cells and convenient, noninvasive tests of single-cell behaviors from molecular markers. Here, a highly versatile single-cell assay is presented that can accommodate different cellular types, enable easy and efficient single-cell loading and culturing, and be suitable for the study of effects of in vitro environmental factors in combination with drug screening. One salient feature of the assay is the noninvasive collection and surveying of single-cell secretions at different time points, producing unprecedented insight of single-cell behaviors based on the biomarker signals from individual cells under given perturbations. Above all, the acquired information is quantitative, for example, measured by the number of exosomes each single-cell secretes for a given time period. Therefore, our single-cell assay provides a convenient, low-cost, and enabling tool for quantitative, time lapsed studies of single-cell properties.


Asunto(s)
Exosomas/metabolismo , Análisis de la Célula Individual/métodos , Línea Celular Tumoral , Humanos , Células MCF-7
6.
Analyst ; 141(13): 4142-50, 2016 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-27163941

RESUMEN

Although a flow cytometer, being one of the most popular research and clinical tools for biomedicine, can analyze cells based on the cell size, internal structures such as granularity, and molecular markers, it provides little information about the physical properties of cells such as cell stiffness and physical interactions between the cell membrane and fluid. In this paper, we propose a computational cell analysis technique using cells' different equilibrium positions in a laminar flow. This method utilizes a spatial coding technique to acquire the spatial position of the cell in a microfluidic channel and then uses mathematical algorithms to calculate the ratio of cell mixtures. Most uniquely, the invented computational cell analysis technique can unequivocally detect the subpopulation of each cell type without labeling even when the cell type shows a substantial overlap in the distribution plot with other cell types, a scenario limiting the use of conventional flow cytometers and machine learning techniques. To prove this concept, we have applied the computation method to distinguish live and fixed cancer cells without labeling, count neutrophils from human blood, and distinguish drug treated cells from untreated cells. Our work paves the way for using computation algorithms and fluidic dynamic properties for cell classification, a label-free method that can potentially classify over 200 types of human cells. Being a highly cost-effective cell analysis method complementary to flow cytometers, our method can offer orthogonal tests in companion with flow cytometers to provide crucial information for biomedical samples.


Asunto(s)
Citometría de Flujo , Técnicas Analíticas Microfluídicas , Algoritmos , Línea Celular Tumoral , Tamaño de la Célula , Humanos , Neutropenia/diagnóstico , Neutrófilos/citología
7.
Nurse Educ Today ; 126: 105831, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37121073

RESUMEN

BACKGROUND: Several authors have previously assessed the effects of assertive communication training for nurses to speak up in cases of medical errors. Inconsistent results regarding the nurses' attitudes, behaviors, and confidence levels were noticed. OBJECTIVE: To identify the effectiveness of assertive communication training on nurses' behaviors, attitudes, and confidence levels for speaking up in cases of medical errors and to identify vital components for success. DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed, ERIC, Embase, Scopus, and CINAHL were searched up for studies published from the inception of the database to December 16, 2022. METHODS: Two researchers independently performed a primary screening of titles and abstracts for relevant studies, followed by a review of full texts if the references met inclusion criteria and quality assessment. Data were retrieved for nurses and nursing students who received medical error-related assertive communication training for speaking up, and learning outcomes for attitudes, behaviors, and confidence levels were reported based on pooled data. Pooled estimates were calculated using a random-effects model. RESULTS: A total of eleven studies with 1299 participants were included in systematic review, and among them nine studies with 804 participants were analyzed in meta-analysis. From the pooled results, the intervention group, which received assertive communication training, exhibited substantially improved speaking-up behaviors compared with the control group (SMD = 0.58; 95 % CI, 0.14-1.03). Considerable differences were noted in the nurses' times of speaking up in cases of medical errors between pretest (38 %; 95 % CI, 0.14-0.68) and posttest (78 %; 95 %CI, 0.70-0.85) based on the pooled data. The nurses' attitudes and confidence levels for speaking up varied markedly between pretest and posttest. CONCLUSION: Structured assertive communication training may improve nurses' speaking-up behaviors in cases of medical errors. To conduct effective assertive communication training, nursing educators should incorporate multiple teaching approaches into structured training and ensure an adequate training duration.


Asunto(s)
Errores Médicos , Enfermeras y Enfermeros , Humanos , Comunicación , Aprendizaje , Asertividad
8.
Polymers (Basel) ; 14(10)2022 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-35631909

RESUMEN

Microfluidic platform technology has presented a new strategy to detect and analyze analytes and biological entities thanks to its reduced dimensions, which results in lower reagent consumption, fast reaction, multiplex, simplified procedure, and high portability. In addition, various forces, such as hydrodynamic force, electrokinetic force, and acoustic force, become available to manipulate particles to be focused and aligned, sorted, trapped, patterned, etc. To fabricate microfluidic chips, silicon was the first to be used as a substrate material because its processing is highly correlated to semiconductor fabrication techniques. Nevertheless, other materials, such as glass, polymers, ceramics, and metals, were also adopted during the emergence of microfluidics. Among numerous applications of microfluidics, where repeated short-time monitoring and one-time usage at an affordable price is required, polymer microfluidics has stood out to fulfill demand by making good use of its variety in material properties and processing techniques. In this paper, the primary fabrication techniques for polymer microfluidics were reviewed and classified into two categories, e.g., mold-based and non-mold-based approaches. For the mold-based approaches, micro-embossing, micro-injection molding, and casting were discussed. As for the non-mold-based approaches, CNC micromachining, laser micromachining, and 3D printing were discussed. This review provides researchers and the general audience with an overview of the fabrication techniques of polymer microfluidic devices, which could serve as a reference when one embarks on studies in this field and deals with polymer microfluidics.

9.
Nurse Educ Today ; 118: 105535, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36084448

RESUMEN

BACKGROUND: Use of interprofessional education has greatly expanded and is widely used to foster interprofessional collaborative practice competency in health professionals, especially during medical emergencies. Identifying the interprofessional education delivery mode that can maximize learning outcomes within available resources is crucial for achieving the sustainability of an interprofessional education program. OBJECTIVES: To examine the learning outcomes of simulation-based interprofessional education and video-enhanced interactive discussion interprofessional education modules and to analyze the variable costs between these two interprofessional education modules. DESIGN: A prospective quasi-experimental study. SETTING: A medical university in Northern Taiwan. PARTICIPANTS: 24 medical students and 48 nursing students enrolled in a 4-week simulation-based interprofessional education or video-enhanced interactive discussion interprofessional education program. METHODS: Students' medical task performance, critical medical task performance, team behavior performance, and interprofessional collaboration attitude were examined at the pretest and posttest by using an objective structured checklist and team performance rating scale with a hands-on simulation model and structured questionnaires. The variable costs for simulation-based interprofessional education and video-enhanced interactive discussion interprofessional education were estimated upon the completion of the course. RESULTS: All learning outcomes significantly improved for both the groups from the pretest to posttest. After the intervention, the simulation-based interprofessional education group exhibited significantly higher scores in medical task performance, critical medical task performance and team behavior performance than the video-enhanced interactive discussion interprofessional education group at the posttest. No significant difference was noted in interprofessional collaboration attitude between the groups. Cost analysis revealed that the simulation-based interprofessional education program was approximately two times more expensive in terms of staffing costs and required 1.3 times greater space charges than the video-enhanced interactive discussion interprofessional education program. CONCLUSION: Both simulation-based interprofessional education and video-enhanced interactive discussion interprofessional education modules effectively improved medical and nursing students' medical task performance, critical medical task performance and team behavior performance. The simulation-based interprofessional education group had more favorable learning outcomes, but the associated costs were higher. Educators should consider both learning outcomes and cost when choosing a design strategy simulation-based interprofessional education vs. video-enhanced interactive discussion interprofessional education for interprofessional education module development.


Asunto(s)
Estudiantes de Medicina , Estudiantes de Enfermería , Actitud del Personal de Salud , Humanos , Educación Interprofesional , Relaciones Interprofesionales , Estudios Prospectivos
10.
Commun Biol ; 4(1): 1130, 2021 09 24.
Artículo en Inglés | MEDLINE | ID: mdl-34561533

RESUMEN

Cellular circulating biomarkers from the primary tumor such as circulating tumor cells (CTCs) and circulating hybrid cells (CHCs) have been described to harbor tumor-like phenotype and genotype. CHCs are present in higher numbers than CTCs supporting their translational potential. Methods for isolation of CHCs do not exist and are restricted to low-throughput, time consuming, and biased methodologies. We report the development of a label-free dielectrophoretic microfluidic platform facilitating enrichment of CHCs in a high-throughput and rapid fashion by depleting healthy peripheral blood mononuclear cells (PBMCs). We demonstrated up to 96.5% depletion of PBMCs resulting in 18.6-fold enrichment of cancer cells. In PBMCs from pancreatic adenocarcinoma patients, the platform enriched neoplastic cells identified by their KRAS mutant status using droplet digital PCR with one hour of processing. Enrichment was achieved in 75% of the clinical samples analyzed, establishing this approach as a promising way to non-invasively analyze tumor cells from patients.


Asunto(s)
Biomarcadores de Tumor/análisis , Dispositivos Laboratorio en un Chip/estadística & datos numéricos , Leucocitos Mononucleares/química , Oncología Médica/métodos , Células Neoplásicas Circulantes/química , Diseño de Equipo , Humanos , Células MCF-7
11.
Sci Rep ; 11(1): 13630, 2021 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-34211050

RESUMEN

Metastatic progression defines the final stages of tumor evolution and underlies the majority of cancer-related deaths. The heterogeneity in disseminated tumor cell populations capable of seeding and growing in distant organ sites contributes to the development of treatment resistant disease. We recently reported the identification of a novel tumor-derived cell population, circulating hybrid cells (CHCs), harboring attributes from both macrophages and neoplastic cells, including functional characteristics important to metastatic spread. These disseminated hybrids outnumber conventionally defined circulating tumor cells (CTCs) in cancer patients. It is unknown if CHCs represent a generalized cancer mechanism for cell dissemination, or if this population is relevant to the metastatic cascade. Herein, we detect CHCs in the peripheral blood of patients with cancer in myriad disease sites encompassing epithelial and non-epithelial malignancies. Further, we demonstrate that in vivo-derived hybrid cells harbor tumor-initiating capacity in murine cancer models and that CHCs from human breast cancer patients express stem cell antigens, features consistent with the potential to seed and grow at metastatic sites. Finally, we reveal heterogeneity of CHC phenotypes reflect key tumor features, including oncogenic mutations and functional protein expression. Importantly, this novel population of disseminated neoplastic cells opens a new area in cancer biology and renewed opportunity for battling metastatic disease.


Asunto(s)
Células Híbridas/patología , Neoplasias/patología , Células Neoplásicas Circulantes/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Biomarcadores de Tumor/análisis , Biomarcadores de Tumor/sangre , Neoplasias de la Mama/sangre , Neoplasias de la Mama/patología , Células Cultivadas , Niño , Preescolar , Femenino , Humanos , Ratones , Persona de Mediana Edad , Invasividad Neoplásica/patología , Neoplasias/sangre
12.
J Clin Med ; 9(5)2020 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-32354170

RESUMEN

Both vasculature and myocardium in the heart are excessively damaged following myocardial infarction (MI), hence therapeutic strategies for treating MI hearts should concurrently aim for true cardiac repair by introducing new cardiomyocytes to replace lost or injured ones. Of them, mesenchymal stem cells (MSCs) have long been considered a promising candidate for cell-based therapy due to their unspecialized, proliferative differentiation potential to specific cell lineage and, most importantly, their capacity of secreting beneficial paracrine factors which further promote neovascularization, angiogenesis, and cell survival. As a consequence, the differentiated MSCs could multiply and replace the damaged tissues to and turn into tissue- or organ-specific cells with specialized functions. These cells are also known to release potent anti-fibrotic factors including matrix metalloproteinases, which inhibit the proliferation of cardiac fibroblasts, thereby attenuating fibrosis. To achieve the highest possible therapeutic efficacy of stem cells, the other interventions, including hydrogels, electrical stimulations, or platelet-derived biomaterials, have been supplemented, which have resulted in a narrow to broad range of outcomes. Therefore, this article comprehensively analyzed the progress made in stem cells and combinatorial therapies to rescue infarcted myocardium.

13.
Lab Chip ; 18(20): 3154-3162, 2018 10 09.
Artículo en Inglés | MEDLINE | ID: mdl-30179236

RESUMEN

Understanding biological heterogeneity at the single cell level is required for advancing insights into the complexity of human physiology and diseases. While advances in technological and analytical methods have afforded unprecedented glimpses of this heterogeneity, the information captured to date largely represents one-time "snap" shots of single cell physiology. To address the limits of existing methods and to accelerate discoveries from single cell studies, we developed a single-cell translocation and secretion assay (TransSeA) that supports time lapse analysis, enables molecular cargo analysis of secretions such as extracellular vesicles (EVs) from single cells, allows massively parallel single cell transfer according to user-defined cell selection criteria, and supports tracking of phenotypes between parental and progeny cells derived from single cells. To demonstrate the unique capabilities and efficiencies of the assay, we present unprecedented single cell studies related to cell secretions, EV cargos and cell intrinsic properties. Although used as examples to demonstrate the feasibility and versatility of the technology, the studies already provided insights into key unanswered questions such as the microRNAs carried by EVs, the relationships between EV secretion rates and gene expressions, and the spontaneous, trans-generational phenotypic changes in EV secretion between parental and progeny cells.


Asunto(s)
Análisis de la Célula Individual/instrumentación , Línea Celular Tumoral , Exosomas/metabolismo , Humanos , MicroARNs/metabolismo , Fenotipo
14.
Bio Protoc ; 7(4)2017 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-28603750

RESUMEN

To study the inhomogeneity within a cell population including exosomes properties such as exosome secretion rate of cells and surface markers carried by exosomes, we need to quantify and characterize those exosomes secreted by each individual cell. Here we develop a method to collect and analyze exosomes secreted by an array of single cells using antibody-modified glass slides that are position-registered to each single cell. After each collection, anti-body conjugated quantum dots are used to label exosomes to allow counting and analysis of exosome surface proteins. Detailed studies of exosome properties related to cell behaviors such as responses to drugs and stress at single cell resolution can be found in the publication (Chiu et al., 2016).

15.
Lab Chip ; 16(1): 153-62, 2016 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-26588203

RESUMEN

We present the development of three-dimensional (3D) cardiac microtissues within a microfluidic device with the ability to quantify real-time contractile stress measurements in situ. Using a 3D patterning technology that allows for the precise spatial distribution of cells within the device, we created an array of 3D cardiac microtissues from neonatal mouse cardiomyocytes. We integrated the 3D micropatterning technology with microfluidics to achieve perfused cell-laden structures. The cells were encapsulated within a degradable gelatin methacrylate hydrogel, which was sandwiched between two polyacrylamide hydrogels. The polyacrylamide hydrogels were used as "stress sensors" to acquire the contractile stresses generated by the beating cardiac cells. The cardiac-specific response of the engineered 3D system was examined by exposing it to epinephrine, an adrenergic neurotransmitter known to increase the magnitude and frequency of cardiac contractions. In response to exogenous epinephrine the engineered cardiac tissues exhibited an increased beating frequency and stress magnitude. Such cost-effective and easy-to-adapt 3D cardiac systems with real-time functional readout could be an attractive technological platform for drug discovery and development.


Asunto(s)
Técnicas Analíticas Microfluídicas , Contracción Miocárdica , Miocitos Cardíacos/citología , Estrés Mecánico , Animales , Hidrogeles/síntesis química , Hidrogeles/química , Metacrilatos/síntesis química , Metacrilatos/química , Ratones , Técnicas Analíticas Microfluídicas/instrumentación , Factores de Tiempo , Ingeniería de Tejidos
16.
ACS Nano ; 9(11): 10655-63, 2015 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-26435065

RESUMEN

Nucleic acid detection and quantification technologies have made remarkable progress in recent years. Among existing platforms, hybridization-based assays have the advantages of being amplification free, low instrument cost, and high throughput, but are generally less sensitive compared to sequencing and PCR assays. To bridge this performance gap, we developed a quantitative physical model for the hybridization-based assay to guide the experimental design, which leads to a pico-liter droplet environment with drastically enhanced performance and detection limit several order above any current microarray platform. The pico-liter droplet hybridization platform is further coupled with the on-chip enrichment technique to yield ultrahigh sensitivity both in terms of target concentration and copy number. Our physical model, taking into account of molecular transport, electrostatic intermolecular interactions, reaction kinetics, suggests that reducing liquid height and optimizing target concentration will maximize the hybridization efficiency, and both conditions can be satisfied in a highly parallel, self-assembled pico-liter droplet microarray that produces a detection limit as low as 570 copies and 50 aM. The pico-liter droplet array device is realized with a micropatterned superhydrophobic black silicon surface that allows enrichment of nucleic acid samples by position-defined evaporation. With on-chip enrichment and oil encapsulated pico-liter droplet arrays, we have demonstrated a record high sensitivity, wide dynamic range (6 orders of magnitude), and marked reduction of hybridization time from >10 h to <5 min in a highly repeatable fashion, benefiting from the physics-driven design and nanofeatures of the device. The design principle and technology can contribute to biomedical sensing and point-of-care clinical applications such as pathogen detection and cancer diagnosis and prognosis.


Asunto(s)
Ácidos Nucleicos/análisis , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , ADN/análisis , Hibridación de Ácido Nucleico , Factores de Tiempo
17.
Lab Chip ; 14(17): 3341-8, 2014 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-24989638

RESUMEN

The inner structure, especially the nuclear structure, of cells carries valuable information about disease and health conditions of a person. Here we demonstrate a label-free technique to enable direct observations and measurements of the size, shape and morphology of the cell nucleus. With a microfabricated lens and a commercial CMOS imager, we form a scanning light-sheet microscope to produce a dark-field optical scattering image of the cell nucleus that overlays with the bright-field image produced in a separate regime of the same CMOS sensor. We have used the device to detect nuclear features that characterize the life cycle of cells and have used the nucleus volume as a new parameter for cell classification. The device can be developed into a portable, low-cost, point-of-care device leveraging the capabilities of the CMOS imagers to be pervasive in mobile electronics.


Asunto(s)
Técnicas Biosensibles , Microcomputadores , Microscopía/métodos , Animales , Leucocitos
18.
Lab Chip ; 13(9): 1803-9, 2013 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-23493956

RESUMEN

We have demonstrated a microfluidic device that can not only achieve three-dimensional flow focusing but also confine particles to the center stream along the channel. The device has a sample channel of smaller height and two sheath flow channels of greater height, merged into the downstream main channel where 3D focusing effects occur. We have demonstrated that both beads and cells in our device display significantly lower CVs in velocity and position distributions as well as reduced probability of coincidental events than they do in conventional 2D-confined microfluidic channels. The improved particle confinement in the microfluidic channel is highly desirable for microfluidic flow cytometers and in fluorescence-activated cell sorting (FACS). We have also reported a novel method to measure the velocity of each individual particle in the microfluidic channel. The method is compatible with the flow cytometer setup and requires no sophisticated visualization equipment. The principles and methods of device design and characterization can be applicable to many types of microfluidic systems.


Asunto(s)
Citometría de Flujo/instrumentación , Microfluídica , Microfluídica/instrumentación , Microfluídica/métodos
19.
Nat Biotechnol ; 31(12): 1126-32, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24213699

RESUMEN

Genome sequencing of single cells has a variety of applications, including characterizing difficult-to-culture microorganisms and identifying somatic mutations in single cells from mammalian tissues. A major hurdle in this process is the bias in amplifying the genetic material from a single cell, a procedure known as polymerase cloning. Here we describe the microwell displacement amplification system (MIDAS), a massively parallel polymerase cloning method in which single cells are randomly distributed into hundreds to thousands of nanoliter wells and their genetic material is simultaneously amplified for shotgun sequencing. MIDAS reduces amplification bias because polymerase cloning occurs in physically separated, nanoliter-scale reactors, facilitating the de novo assembly of near-complete microbial genomes from single Escherichia coli cells. In addition, MIDAS allowed us to detect single-copy number changes in primary human adult neurons at 1- to 2-Mb resolution. MIDAS can potentially further the characterization of genomic diversity in many heterogeneous cell populations.


Asunto(s)
Separación Celular/instrumentación , Mapeo Cromosómico/instrumentación , Clonación Molecular/métodos , ADN Polimerasa Dirigida por ADN/genética , ADN/genética , Secuenciación de Nucleótidos de Alto Rendimiento/instrumentación , Nanotecnología/instrumentación , Diseño de Equipo , Análisis de Falla de Equipo , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Nanotecnología/métodos
20.
Kaohsiung J Med Sci ; 26(8): 448-55, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20705257

RESUMEN

In this report, we describe a 31-year-old man in whom acute pancreatitis was the initial feature of a subsequently diagnosed pancreatic adenocarcinoma with multiple metastases. He initially presented at our hospital with acute pancreatitis. Abdominal ultrasonography revealed a mildly dilated pancreatic duct and an enlarged pancreatic head. Although a follow-up abdominal ultrasonography revealed a progressively dilated pancreatic duct and a progressively enlarged pancreatic head, he refused further investigation and was lost to follow-up. Four months later, he returned to our hospital with relapsed acute pancreatitis. Obstructive jaundice was noted and drainage was performed. Because choledochoplasty with multiple balloon catheters was not fully effective, biliary tract bypass surgery was carried out. Intraoperative biopsy confirmed pancreatic adenocarcinoma with multiple metastases. The patient died of massive gastrointestinal bleeding a few weeks later. To our knowledge, this is the youngest case of pancreatic cancer with the uncommon initial presentation of acute pancreatitis reported in the literature. For a patient with acute pancreatitis, particularly recurrent episodes, but with no known risk factors for pancreatitis, a pancreatic neoplasm should be considered as a potential underlying cause, even in a young man.


Asunto(s)
Neoplasias Pancreáticas/diagnóstico , Pancreatitis/diagnóstico , Enfermedad Aguda/terapia , Adulto , Resultado Fatal , Humanos , Masculino , Neoplasias Pancreáticas/diagnóstico por imagen , Neoplasias Pancreáticas/cirugía , Pancreatitis/diagnóstico por imagen , Pancreatitis/patología , Recurrencia , Ultrasonografía
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