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Find video protocols related to scientific articles indexed in Pubmed.
Host cell protein testing by ELISAs and the use of orthogonal methods.
Biotechnol. Bioeng.
PUBLISHED: 04-10-2014
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Host cell proteins (HCPs) are among the process-related impurities monitored during recombinant protein pharmaceutical process development. The challenges of HCP detection include (1) low levels of residual HCPs present in large excess of product protein, (2) the assay must measure a large number of different protein analytes, and (3) the population of HCP species may change during process development. Suitable methods for measuring process-related impurities are needed to support process development, process validation, and control system testing. A multi-analyte enzyme-linked immunosorbent assay (ELISA) is the workhorse method for HCP testing due to its high throughput, sensitivity and selectivity. However, as the anti-HCP antibodies, the critical reagents for HCP ELISA, do not comprehensively recognize all the HCP species, it is especially important to ensure that weak and non-immunoreactive HCPs are not overlooked by the ELISA. In some cases limited amount of antibodies to HCP species or antigen excess causes dilution-dependent non-linearity with multi-product HCP ELISA. In our experience, correct interpretation of assay data can lead to isolation and identification of co-purifying HCP with the product in some cases. Moreover, even if the antibodies for a particular HCP are present in the reagent, the corresponding HCP may not be readily detected in the ELISA due to antibody/antigen binding conditions and availability of HCP epitopes. This report reviews the use of the HCP ELISA, discusses its limitations, and demonstrates the importance of orthogonal methods, including mass spectrometry, to complement the platform HCP ELISA for support of process development. In addition, risk and impact assessment for low-level HCPs is also outlined, with consideration of clinical information. Biotechnol. Bioeng. 2014;111: 2367-2379. © 2014 Wiley Periodicals, Inc.
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Does numeracy correlate with measures of health literacy in the emergency department?
Acad Emerg Med
PUBLISHED: 03-29-2014
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The objective was to quantify the correlation between general numeracy and health literacy in an emergency department (ED) setting.
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Feasibility and diagnostic accuracy of brief health literacy and numeracy screening instruments in an urban emergency department.
Acad Emerg Med
PUBLISHED: 03-29-2014
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The objective was to evaluate the diagnostic accuracy of five health literacy screening instruments in emergency department (ED) patients: the Rapid Evaluation of Adult Literacy in Medicine-Revised (REALM-R), the Newest Vital Sign (NVS), Single Item Literacy Screens (SILS), health numeracy, and physician gestalt. A secondary objective was to evaluate the feasibility of these instruments as measured by administration time, time on task, and interruptions during test administration.
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CT screening and follow-up of lung nodules: effects of tube current-time setting and nodule size and density on detectability and of tube current-time setting on apparent size.
AJR Am J Roentgenol
PUBLISHED: 08-25-2011
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The purpose of the study was to quantify and compare the effect of CT dose and of size and density of nodules on the detectability of lung nodules and to quantify the influence of CT dose on the size of the nodules.
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Diagnosing invasive fungal disease in critically ill patients.
Crit. Rev. Microbiol.
PUBLISHED: 07-13-2011
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Fungal infections are increasing, with a changing landscape of pathogens and emergence of new groups at risk for invasive disease. We review current diagnostic techniques, focusing on studies in critically ill patients. Microbiological cultures, the current "gold standard", demonstrate poor sensitivity, thus diagnosis of invasive disease in the critically ill is difficult. This diagnostic dilemma results in under- or over-treatment of patients, potentially contributing to poor outcomes and antifungal resistance. While other current diagnostic tests perform moderately well, many lack timeliness, efficacy, and are negatively affected by treatments common to critically ill patients. New nucleic acid-based research is promising.
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The association between dietary intake and cervical intraepithelial neoplasia grade 2 or higher among women in a high-risk rural area of China.
Arch. Gynecol. Obstet.
PUBLISHED: 06-29-2011
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To evaluate the relationship between dietary intake and risk of cervical intraepithelial neoplasia grade 2 or higher (CIN2+) while controlling for human papillomavirus (HPV) infection.
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An empirical analysis of overlap publication in Chinese language and English research manuscripts.
PLoS ONE
PUBLISHED: 06-18-2011
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There are a number of sound justifications for publishing nearly identical information in Chinese and English medical journals, assuming several conditions are met. Although overlap publication is perceived as undesirable and ethically questionable in Europe and North America, it may serve an important function in some regions where English is not the native tongue. There is no empirical data on the nature and degree of overlap publication in English and Chinese language journals.
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CT patterns of fungal pulmonary infections of the lung: comparison of standard-dose and simulated low-dose CT.
Eur J Radiol
PUBLISHED: 05-12-2011
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To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients.
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Performance of high-risk human papillomavirus DNA testing as a primary screen for cervical cancer: a pooled analysis of individual patient data from 17 population-based studies from China.
Lancet Oncol.
PUBLISHED: 11-11-2010
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Controversy remains over whether high-risk human papillomavirus (HPV) DNA testing should be used as a primary screen for cervical cancer. The aims of our study were to assess whether HPV DNA testing could be applied to cervical-cancer screening programmes in China, as well as other similar developing countries.
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Animal cells connected by nanotubes can be electrically coupled through interposed gap-junction channels.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 09-20-2010
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Tunneling nanotubes (TNTs) are recently discovered conduits for a previously unrecognized form of cell-to-cell communication. These nanoscale, F-actin-containing membrane tubes connect cells over long distances and facilitate the intercellular exchange of small molecules and organelles. Using optical membrane-potential measurements combined with mechanical stimulation and whole-cell patch-clamp recording, we demonstrate that TNTs mediate the bidirectional spread of electrical signals between TNT-connected normal rat kidney cells over distances of 10 to 70 ?m. Similar results were obtained for other cell types, suggesting that electrical coupling via TNTs may be a widespread characteristic of animal cells. Strength of electrical coupling depended on the length and number of TNT connections. Several lines of evidence implicate a role for gap junctions in this long-distance electrical coupling: punctate connexin 43 immunoreactivity was frequently detected at one end of TNTs, and electrical coupling was voltage-sensitive and inhibited by meclofenamic acid, a gap-junction blocker. Cell types lacking gap junctions did not show TNT-dependent electrical coupling, which suggests that TNT-mediated electrical signals are transmitted through gap junctions at a membrane interface between the TNT and one cell of the connected pair. Measurements of the fluorescent calcium indicator X-rhod-1 revealed that TNT-mediated depolarization elicited threshold-dependent, transient calcium signals in HEK293 cells. These signals were inhibited by the voltage-gated Ca(2+) channel blocker mibefradil, suggesting they were generated via influx of calcium through low voltage-gated Ca(2+) channels. Taken together, our data suggest a unique role for TNTs, whereby electrical synchronization between distant cells leads to activation of downstream target signaling.
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Freehand MRI-guided preoperative needle localization of breast lesions after MRI-guided vacuum-assisted core needle biopsy without marker placement.
J Magn Reson Imaging
PUBLISHED: 06-25-2010
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To evaluate the feasibility of magnetic resonance imaging (MRI)-guided preoperative needle localization (PNL) of breast lesions previously sampled by MRI-guided vacuum-assisted core needle biopsy (VACNB) without marker placement.
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Electrical coupling and passive membrane properties of AII amacrine cells.
J. Neurophysiol.
PUBLISHED: 01-20-2010
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AII amacrine cells in the mammalian retina are connected via electrical synapses to on-cone bipolar cells and to other AII amacrine cells. To understand synaptic integration in these interneurons, we need information about the junctional conductance (g(j)), the membrane resistance (r(m)), the membrane capacitance (C(m)), and the cytoplasmic resistivity (R(i)). Due to the extensive electrical coupling, it is difficult to obtain estimates of r(m), as well as the relative contribution of the junctional and nonjunctional conductances to the total input resistance of an AII amacrine cell. Here we used dual voltage-clamp recording of pairs of electrically coupled AII amacrine cells in an in vitro slice preparation from rat retina and applied meclofenamic acid (MFA) to block the electrical coupling and isolate single AII amacrines electrically. In the control condition, the input resistance (R(in)) was approximately 620 Mohms and the apparent r(m) was approximately 760 Mohms. After block of electrical coupling, determined by estimating g(j) in the dual recordings, R(in) and r(m) were approximately 4,400 Mohms, suggesting that the nongap junctional conductance of an AII amacrine cell is approximately 16% of the total input conductance. Control experiments with nucleated patches from AII amacrine cells suggested that MFA had no effect on the nongap junctional membrane of these cells. From morphological reconstructions of AII amacrine cells filled with biocytin, we obtained a surface area of approximately 900 microm(2) which, with a standard value for C(m) of 0.01 pF/microm(2), corresponds to an average capacitance of approximately 9 pF and a specific membrane resistance of approximately 41 kohms cm(2). Together with information concerning synaptic connectivity, these data will be important for developing realistic compartmental models of the network of AII amacrine cells.
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Accurate measurement of junctional conductance between electrically coupled cells with dual whole-cell voltage-clamp under conditions of high series resistance.
J. Neurosci. Methods
PUBLISHED: 01-14-2010
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Accurate measurement of the junctional conductance (G(j)) between electrically coupled cells can provide important information about the functional properties of coupling. With the development of tight-seal, whole-cell recording, it became possible to use dual, single-electrode voltage-clamp recording from pairs of small cells to measure G(j). Experiments that require reduced perturbation of the intracellular environment can be performed with high-resistance pipettes or the perforated-patch technique, but an accompanying increase in series resistance (R(s)) compromises voltage-clamp control and reduces the accuracy of G(j) measurements. Here, we present a detailed analysis of methodologies available for accurate determination of steady-state G(j) and related parameters under conditions of high R(s), using continuous or discontinuous single-electrode voltage-clamp (CSEVC or DSEVC) amplifiers to quantify the parameters of different equivalent electrical circuit model cells. Both types of amplifiers can provide accurate measurements of G(j), with errors less than 5% for a wide range of R(s) and G(j) values. However, CSEVC amplifiers need to be combined with R(s)-compensation or mathematical correction for the effects of nonzero R(s) and finite membrane resistance (R(m)). R(s)-compensation is difficult for higher values of R(s) and leads to instability that can damage the recorded cells. Mathematical correction for R(s) and R(m) yields highly accurate results, but depends on accurate estimates of R(s) throughout an experiment. DSEVC amplifiers display very accurate measurements over a larger range of R(s) values than CSEVC amplifiers and have the advantage that knowledge of R(s) is unnecessary, suggesting that they are preferable for long-duration experiments and/or recordings with high R(s).
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Meclofenamic acid blocks electrical synapses of retinal AII amacrine and on-cone bipolar cells.
J. Neurophysiol.
PUBLISHED: 03-11-2009
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Gap junction channels constitute specialized intercellular contacts that can serve as electrical synapses. In the rod pathway of the retina, electrical synapses between AII amacrine cells express connexin 36 (Cx36) and electrical synapses between AII amacrines and on-cone bipolar cells express Cx36 on the amacrine side and Cx36 or Cx45 on the bipolar side. For physiological investigations of the properties and functions of these electrical synapses, it is highly desirable to have access to potent pharmacological blockers with selective and reversible action. Here we use dual whole cell voltage-clamp recordings of pairs of AII amacrine cells and pairs of AII amacrine and on-cone bipolar cells in rat retinal slices to directly measure the junctional conductance (G(j)) between electrically coupled cells and to study the effect of the drug meclofenamic acid (MFA) on G(j). Consistent with previous tracer coupling studies, we found that MFA reversibly blocked the electrical synapse currents in a concentration-dependent manner, with complete block at 100 muM. Whereas MFA evoked a detectable decrease in G(j) within minutes of application, the time to complete block of G(j) was considerably longer, typically 20-40 min. After washout, G(j) recovered to 20-90% of the control level, but the time to maximum recovery was typically >1 h. These results suggest that MFA can be a useful drug to investigate the physiological functions of electrical synapses in the rod pathway, but that the slow kinetics of block and reversal might compromise interpretation of the results and that explicit monitoring of G(j) is desirable.
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Passive membrane properties and electrotonic signal processing in retinal rod bipolar cells.
J. Physiol. (Lond.)
PUBLISHED: 01-05-2009
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Rod bipolar cells transmit visual signals from their dendrites, where they receive input from rod photoreceptors, to their axon terminals, where they synapse onto amacrine cells. Little is known, however, about the transmission and possible transformation of these signals. We have combined axon terminal recording in retinal slices, quantitative, light-microscopic morphological reconstruction and computer modelling to obtain detailed compartmental models of rat rod bipolar cells. Passive cable properties were estimated by directly fitting the current responses of the models evoked by voltage pulses to the physiologically recorded responses. At a holding potential of -60 mV, the average best-fit parameters were 1.1 microF cm(-2) for specific membrane capacitance (C(m)), 130 Omega cm for cytoplasmic resistivity (R(i)), and 24 kOmega cm(2) for specific membrane resistance (R(m)). The passive integration of excitatory and inhibitory synaptic inputs was examined by computer modelling with physiologically realistic synaptic conductance waveforms. For both transient and steady-state synaptic inhibition, the inhibitory effect was relatively insensitive to the location of the inhibition. For transient synaptic inhibition, the time window of effective inhibition depended critically on the relative timing of inhibition and excitation. The passive signal transmission between soma and axon terminal was examined by the electrotonic transform and quantified as the frequency-dependent voltage attenuation of sinusoidal voltage waveforms. For the range of parameters explored (axon diameter and length, R(i)), the lowest cutoff frequency observed was approximately 300 Hz, suggesting that realistic scotopic visual signals will be faithfully transmitted from soma to axon terminal, with minimal passive attenuation along the axon.
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Electrical synapses between AII amacrine cells in the retina: Function and modulation.
Brain Res.
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Adaptation enables the visual system to operate across a large range of background light intensities. There is evidence that one component of this adaptation is mediated by modulation of gap junctions functioning as electrical synapses, thereby tuning and functionally optimizing specific retinal microcircuits and pathways. The AII amacrine cell is an interneuron found in most mammalian retinas and plays a crucial role for processing visual signals in starlight, twilight and daylight. AII amacrine cells are connected to each other by gap junctions, potentially serving as a substrate for signal averaging and noise reduction, and there is evidence that the strength of electrical coupling is modulated by the level of background light. Whereas there is extensive knowledge concerning the retinal microcircuits that involve the AII amacrine cell, it is less clear which signaling pathways and intracellular transduction mechanisms are involved in modulating the junctional conductance between electrically coupled AII amacrine cells. Here we review the current state of knowledge, with a focus on the recent evidence that suggests that the modulatory control involves activity-dependent changes in the phosphorylation of the gap junction channels between AII amacrine cells, potentially linked to their intracellular Ca(2+) dynamics. This article is part of a Special Issue entitled Electrical Synapses.
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Pooled analysis of a self-sampling HPV DNA Test as a cervical cancer primary screening method.
J. Natl. Cancer Inst.
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Worldwide, one-seventh of cervical cancers occur in China, which lacks a national screening program. By evaluating the diagnostic accuracy of self-collected cervicovaginal specimens tested for human papillomavirus (HPV) DNA (Self-HPV testing) in China, we sought to determine whether Self-HPV testing may serve as a primary cervical cancer screening method in low-resource settings.
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Age-specific human papillomavirus antibody and deoxyribonucleic acid prevalence: a global review.
J Adolesc Health
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Global data on human papillomavirus (HPV) serological and deoxyribonucleic acid (DNA) prevalence are essential to optimize HPV prophylactic vaccination strategies.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.